Science.gov

Sample records for interface studies technical

  1. Shuttle payload interface verification equipment study. Volume 2: Technical document, part 1

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The technical analysis is reported that was performed during the shuttle payload interface verification equipment study. It describes: (1) the background and intent of the study; (2) study approach and philosophy covering all facets of shuttle payload/cargo integration; (3)shuttle payload integration requirements; (4) preliminary design of the horizontal IVE; (5) vertical IVE concept; and (6) IVE program development plans, schedule and cost. Also included is a payload integration analysis task to identify potential uses in addition to payload interface verification.

  2. Shuttle payload interface verification equipment study. Volume 2: Technical document. Part 2: Appendices

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Appendices to the shuttle payload integration study provide for: (1) The interface verification equipment hardware utilization list; (2) the horizontal IVE in-field assembly procedure; and (3) payload integration baseline functional flow block diagrams and options.

  3. [Surface science instrumentation for the study of important catalytic and electrochemical interfaces]. Annual technical report

    SciTech Connect

    Not Available

    1992-12-31

    The equipment combines several standard surface science probes (uv photoelectron spectra, thermal desorption, AES) with a state-of-the art x-ray photoelectron spectrometer and integrates with a dry box and a custom electrochemical cell. After the LEED chamber was remachined, the instrument has been performing satisfactorily. Various studies using the instrument were conducted in cooperation with other groups. Si surfaces were studied before and after use as a photoanode in a photoelectrochemical cell.

  4. [Technical production and its interface with nursing].

    PubMed

    Mendes, Isabel Amélia; Leite, Joséte Luzia; Trevizan, Maria Auxiliadora; Trezza, Maria Cristina; dos Santos, Regina Maria

    2002-01-01

    This is a descriptive study which subject concerns the interfaces of technological production with nursing. Its objectives is to analyse the interface of technological production with nursing and to discuss that production on the following dimensions: instructional, instrumental and informatic. To develop this the summaries of the papers presented during the last three editions of the Congresso Brasileiro de Enfermagem--1998, 1999 and 2000 were used as a source of information. The inherent subjectivity of a study of summaries was considered a limitation, since it is possible that a miscomprehension between our understanding and the real idea of the author occur. This study showed that Nursing, even in an incipient manner, has been producing constitutive components of the technological production, on its daily work. PMID:12817540

  5. Software Engineering for User Interfaces. Technical Report.

    ERIC Educational Resources Information Center

    Draper, Stephen W.; Norman, Donald A.

    The discipline of software engineering can be extended in a natural way to deal with the issues raised by a systematic approach to the design of human-machine interfaces. The user should be treated as part of the system being designed and projects should be organized to take into account the current lack of a priori knowledge of user interface…

  6. Databases Improve Technical Studies

    ERIC Educational Resources Information Center

    Graube, Gabriele

    2004-01-01

    In Lower Saxony, technology studies as part of preparing technical education teachers for primary and partly for secondary education can be studied only at two universities--the Technical University of Brunswick and the University of Oldenburg. Technology education is not available at the Gymnasium (a type of secondary school leading to the…

  7. Cognitive Task Analysis, Interface Design, and Technical Troubleshooting.

    ERIC Educational Resources Information Center

    Steinberg, Linda S.; Gitomer, Drew H.

    A model of the interface design process is proposed that makes use of two interdependent levels of cognitive analysis: the study of the criterion task through an analysis of expert/novice differences and the evaluation of the working user interface design through the application of a practical interface analysis methodology (GOMS model). This dual…

  8. [Charge generation and separation at liquid interfaces]. Technical progress report

    SciTech Connect

    Eisenthal, K.B.

    1992-12-01

    The research is divided into 3 parts: (1)Sum Frequency Generation (SFG) and Monolayer Structure. Picosecond lasers are combined by difference frequency mixing in a nonlinear crystal to generate picosecond, tunable IR pulses, which are used to study orientation of C{double_bond}N and CD{sub 3} chromosphores (head group and tail) on lipid monolayers CD{sub 3}(CH{sub 2}){sub 21}CN at air/water interface. (2)Femtosecond Dynamics. The femtosecond colliding pulse mode locked laser is being modified to carry out pump-second harmonic (SH) probe studies at liquid interfaces. Picosecond SH knowhow of intermolecular energy transfer, excited state isomerization, and rotational motions at interfaces is now being applied to femtosecond scale. Aromatics adsorbed at air/water interface, generated changes in SH probe signal and their decay back to original value. If the laser is tightly focussed at interface, multiphoton absorption processes occur which destroy the sample; this effect will be exploited. (3)Interface Potential and Acid-Base Equilibria. The interface potential is a key to charge transport; using SHG, we plan to measure the pKa of organic acids at interfaces. In these studies at silica/aqueous interface, the water molecules extending from the interface into the bulk (about 50{Angstrom}) were strongly polarized by SiO{sup {minus}} charges at the interface. In summary, a new spectroscopic technique is being applied to study of neutral and charged lipid monolayers, interface pKa values, interface potential and orientational structure and vibrational spectroscopy of lipids.

  9. EUDISED: Technical Studies, 1971.

    ERIC Educational Resources Information Center

    Council of Europe, Strasbourg (France). Documentation Center for Education in Europe.

    This collection of technical studies concerning the European Documentation and Information System for Education (EUDISED) presents the problems of educational information, documentation, and dissemination in Europe. In the first report, transmitter-receiver relationships and the understanding of each other's roles and needs are discussed. The…

  10. Knowledge-based graphical interfaces for presenting technical information

    NASA Technical Reports Server (NTRS)

    Feiner, Steven

    1988-01-01

    Designing effective presentations of technical information is extremely difficult and time-consuming. Moreover, the combination of increasing task complexity and declining job skills makes the need for high-quality technical presentations especially urgent. We believe that this need can ultimately be met through the development of knowledge-based graphical interfaces that can design and present technical information. Since much material is most naturally communicated through pictures, our work has stressed the importance of well-designed graphics, concentrating on generating pictures and laying out displays containing them. We describe APEX, a testbed picture generation system that creates sequences of pictures that depict the performance of simple actions in a world of 3D objects. Our system supports rules for determining automatically the objects to be shown in a picture, the style and level of detail with which they should be rendered, the method by which the action itself should be indicated, and the picture's camera specification. We then describe work on GRIDS, an experimental display layout system that addresses some of the problems in designing displays containing these pictures, determining the position and size of the material to be presented.

  11. PHOTOS interface in C++. Technical and physics documentation

    NASA Astrophysics Data System (ADS)

    Davidson, N.; Przedzinski, T.; Was, Z.

    2016-02-01

    For five years now, PHOTOS Monte Carlo for bremsstrahlung in the decay of particles and resonances has been available with an interface to the C++ HepMC event record. The main purpose of the present paper is to document the technical aspects of the PHOTOS Monte Carlo installation and present version use. A multitude of test results and examples are distributed together with the program code. The PHOTOS C++ physics precision is better than its FORTRAN predecessor and more convenient steering options are also available. An algorithm for the event record interface necessary for process dependent photon emission kernel is implemented. It is used in Z and W decays for kernels of complete first order matrix elements of the decays. Additional emission of final state lepton pairs is also available. Physics assumptions used in the program and properties of the solution are reviewed. In particular, it is explained how the second order matrix elements were used in design and validation of the program iteration procedure. Also, it is explained that the phase space parameterization used in the program is exact.

  12. Methods for Improving the User-Computer Interface. Technical Report.

    ERIC Educational Resources Information Center

    McCann, Patrick H.

    This summary of methods for improving the user-computer interface is based on a review of the pertinent literature. Requirements of the personal computer user are identified and contrasted with computer designer perspectives towards the user. The user's psychological needs are described, so that the design of the user-computer interface may be…

  13. Improving SOLO's User-Interface: An Empirical Study of User Behavior and a Proposal for Cost Effectiveness Enhancements to SOLO. CAL Research Group Technical Report No. 7.

    ERIC Educational Resources Information Center

    Lewis, Matthew W.

    This report describes an in-depth analysis of the errors made by users of SOLO, a programming language written for Open University students studying cognitive psychology. The study was designed to (1) determine the effectiveness of SOLO's current error-handling routines by evaluating how often SOLO produced "sensible" messages or automatic…

  14. Interface between object-oriented systems. Technical report

    SciTech Connect

    Crowl, L.A.

    1987-04-01

    The Chrysalis operating system for the Butterfly Parallel Processor presents an object-oriented programming environment based on shared memory. However, because of Chrysalis's low-level orientation and its use of type-unsafe features of the C programming language, programs using the environment are difficult to program and highly error-prone. Using C as the primary programming language for the Butterfly does not fully realize the benefit of Chrysalis's object orientation. An object-oriented programming language is natural candidate for improving the Chrysalis environment. The C ++ programming language provides a number of advantages in developing such an interface. This paper reports the successes and problems encountered in the development of Chrysalis ++, a C ++ interface to Chrysalis ++ uncovered many strengths and weakness in C ++. Some apply to C ++ in general, others apply only to its adaptation to a parallel programming environment. It is important to note that C++ is a sequential language; it is use in a parallel programming environment is therefore outside the bounds of its design.

  15. Nonlinear optical studies of polymer interfaces

    SciTech Connect

    Shen, Y.R. |

    1993-11-01

    Second-order nonlinear optical processes can be used as effective surface probes. They can provide some unique opportunities for studies of polymer interfaces. Here the author describes two examples to illustrate the potential of the techniques. One is on the formation of metal/polymer interfaces. The other is on the alignment of liquid crystal films by mechanically rubbed polymer surfaces.

  16. High temperature ceramic interface study

    NASA Technical Reports Server (NTRS)

    Lindberg, L. J.

    1984-01-01

    Monolithic SiC and Si3N4 are susceptible to contact stress damage at static and sliding interfaces. Transformation-toughened zirconia (TTZ) was evaluated under sliding contact conditions to determine if the higher material fracture toughness would reduce the susceptibility to contact stress damage. Contact stress tests were conducted on four commercially available TTZ materials at normal loads ranging from 0.455 to 22.7 kg (1 to 50 pounds) at temperatures ranging from room temperature to 1204C (2200 F). Static and dynamic friction were measured as a function of temperature. Flexural strength measurements after these tests determined that the contact stress exposure did not reduce the strength of TTZ at contact loads of 0.455, 4.55, and 11.3 kg (1, 10, and 25 pounds). Prior testing with the lower toughness SiC and Si3N4 materials resulted in a substantial strength reduction at loads of only 4.55 and 11.3 kg (10 and 25 pounds). An increase in material toughness appears to improve ceramic material resistance to contact stress damage. Baseline material flexure strength was established and the stress rupture capability of TTZ was evaluated. Stress rupture tests determined that TTZ materials are susceptible to deformation due to creep and that aging of TTZ materials at elevated temperatures results in a reduction of material strength.

  17. FY07 Summary of System Interface and Support Systems R&D and Technical Issues Map

    SciTech Connect

    Steven R. Sherman

    2007-09-01

    This document provides a summary of research and development activities in the System Interface and Support Systems area of the DOE Nuclear Hydrogen Initiative in FY 2007. Project cost and performance data obtained from the PICS system, at least up through July 2007, are presented and analyzed. Brief summaries of accomplishments and references are provided. A mapping of System Interface and Support Systems technical issues versus the work performed is updated and presented. Lastly, near-term research plans are described, and recommendatioins are provided for additional research.

  18. Head Start Impact Study. Technical Report

    ERIC Educational Resources Information Center

    Puma, Michael; Bell, Stephen; Cook, Ronna; Heid, Camilla; Shapiro, Gary; Broene, Pam; Jenkins, Frank; Fletcher, Philip; Quinn, Liz; Friedman, Janet; Ciarico, Janet; Rohacek, Monica; Adams, Gina; Spier, Elizabeth

    2010-01-01

    This Technical Report is designed to provide technical detail to support the analysis and findings presented in the "Head Start Impact Study Final Report" (U.S. Department of Health and Human Services, January 2010). Chapter 1 provides an overview of the Head Start Impact Study and its findings. Chapter 2 provides technical information on the…

  19. Solar thermochemical process interface study

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The design and analyses of a subsystem of a hydrogen production process are described. The process is based on solar driven thermochemical reactions. The subject subsystem receives sulfuric acid of 60% concentration at 100 C, 1 atm pressure. The acid is further concentrated, vaporized, and decomposed (at a rate of 122 g moles/sec H2SO4) into SO2, O2, and water. The produce stream is cooled to 100 C. Three subsystem options, each being driven by direct solar energy, were designed and analyzed. The results are compared with a prior study case in which solar energy was provided indirectly through a helium loop.

  20. Insights from the study of high-temperature interface superconductivity.

    PubMed

    Pereiro, J; Bollinger, A T; Logvenov, G; Gozar, A; Panagopoulos, C; Bozović, I

    2012-10-28

    A brief overview is given of the studies of high-temperature interface superconductivity based on atomic-layer-by-layer molecular beam epitaxy (ALL-MBE). A number of difficult materials science and physics questions have been tackled, frequently at the expense of some technical tour de force, and sometimes even by introducing new techniques. ALL-MBE is especially suitable to address questions related to surface and interface physics. Using this technique, it has been demonstrated that high-temperature superconductivity can occur in a single copper oxide layer-the thinnest superconductor known. It has been shown that interface superconductivity in cuprates is a genuine electronic effect-it arises from charge transfer (electron depletion and accumulation) across the interface driven by the difference in chemical potentials rather than from cation diffusion and mixing. We have also understood the nature of the superconductor-insulator phase transition as a function of doping. However, a few important questions, such as the mechanism of interfacial enhancement of the critical temperature, are still outstanding. PMID:22987034

  1. Gas Gun Studies of Interface Wear Effects

    NASA Astrophysics Data System (ADS)

    Jackson, Tyler; Kennedy, Greg; Thadhani, Naresh

    2011-06-01

    The characteristics of interface wear were studied by performing gas gun experiments at velocities up to 1 km/s. The approach involved developing coefficients of constitutive strength models for Al 6061 and OFHC-Cu, then using those to design die geometry for interface wear gas gun experiments. Taylor rod-on-anvil impact experiments were performed to obtain coefficients of the Johnson-Cook constitutive strength model by correlating experimentally obtained deformed states of impacted samples with those predicted using ANSYS AUTODYN hydrocode. Simulations were used with validated strength models to design geometry involving acceleration of Al rods through a copper concentric cylindrical angular extrusion die. Experiments were conducted using 7.62 mm and 80 mm diameter gas guns. Differences in the microstructure of the interface layer and microhardness values illustrate that stress-strain conditions produced during acceleration of Al through the hollow concentric copper die, at velocities less than 800 m/s, result in formation of a layer via solid state alloying due to severe plastic deformation, while higher velocities produce an interface layer consisting of melted and re-solidified aluminum.

  2. Human-system Interfaces to Automatic Systems: Review Guidance and Technical Basis

    SciTech Connect

    OHara, J.M.; Higgins, J.C.

    2010-01-31

    Automation has become ubiquitous in modern complex systems and commercial nuclear power plants are no exception. Beyond the control of plant functions and systems, automation is applied to a wide range of additional functions including monitoring and detection, situation assessment, response planning, response implementation, and interface management. Automation has become a 'team player' supporting plant personnel in nearly all aspects of plant operation. In light of the increasing use and importance of automation in new and future plants, guidance is needed to enable the NRC staff to conduct safety reviews of the human factors engineering (HFE) aspects of modern automation. The objective of the research described in this report was to develop guidance for reviewing the operator's interface with automation. We first developed a characterization of the important HFE aspects of automation based on how it is implemented in current systems. The characterization included five dimensions: Level of automation, function of automation, modes of automation, flexibility of allocation, and reliability of automation. Next, we reviewed literature pertaining to the effects of these aspects of automation on human performance and the design of human-system interfaces (HSIs) for automation. Then, we used the technical basis established by the literature to develop design review guidance. The guidance is divided into the following seven topics: Automation displays, interaction and control, automation modes, automation levels, adaptive automation, error tolerance and failure management, and HSI integration. In addition, we identified insights into the automaton design process, operator training, and operations.

  3. Two-Fluid Interface Instability Being Studied

    NASA Technical Reports Server (NTRS)

    Niederhaus, Charles E.

    2003-01-01

    The interface between two fluids of different density can experience instability when gravity acts normal to the surface. The relatively well known Rayleigh-Taylor (RT) instability results when the gravity is constant with a heavy fluid over a light fluid. An impulsive acceleration applied to the fluids results in the Richtmyer-Meshkov (RM) instability. The RM instability occurs regardless of the relative orientation of the heavy and light fluids. In many systems, the passing of a shock wave through the interface provides the impulsive acceleration. Both the RT and RM instabilities result in mixing at the interface. These instabilities arise in a diverse array of circumstances, including supernovas, oceans, supersonic combustion, and inertial confinement fusion (ICF). The area with the greatest current interest in RT and RM instabilities is ICF, which is an attempt to produce fusion energy for nuclear reactors from BB-sized pellets of deuterium and tritium. In the ICF experiments conducted so far, RM and RT instabilities have prevented the generation of net-positive energy. The $4 billion National Ignition Facility at Lawrence Livermore National Laboratory is being constructed to study these instabilities and to attempt to achieve net-positive yield in an ICF experiment.

  4. Uranium(IV) Interaction with Aqueous/Solid Interfaces Studied by Nonlinear Optics

    SciTech Connect

    Geiger, Franz

    2015-03-27

    This is the Final Technical Report for "Uranium(IV) Interaction with Aqueous/Solid Interfaces Studied by Nonlinear Optics", by Franz M. Geiger, PI, from Northwestern University, IL, USA, Grant Number SC0004101 and/or DE-PS02-ER09-07.

  5. FAO-OIE-WHO Joint Technical Consultation on Avian Influenza at the Human-Animal Interface.

    PubMed

    Anderson, Tara; Capua, Ilaria; Dauphin, Gwenaëlle; Donis, Ruben; Fouchier, Ron; Mumford, Elizabeth; Peiris, Malik; Swayne, David; Thiermann, Alex

    2010-05-01

    For the past 10 years, animal health experts and human health experts have been gaining experience in the technical aspects of avian influenza in mostly separate fora. More recently, in 2006, in a meeting of the small WHO Working Group on Influenza Research at the Human Animal Interface (Meeting report available from: http://www.who.int/csr/resources/publications/influenza/WHO_CDS_EPR_GIP_2006_3/en/index.html) in Geneva allowed influenza experts from the animal and public health sectors to discuss together the most recent avian influenza research. Ad hoc bilateral discussions on specific technical issues as well as formal meetings such as the Technical Meeting on HPAI and Human H5N1 Infection (Rome, June, 2007; information available from: http://www.fao.org/avianflu/en/conferences/june2007/index.html) have increasingly brought the sectors together and broadened the understanding of the topics of concern to each sector. The sectors have also recently come together at the broad global level, and have developed a joint strategy document for working together on zoonotic diseases (Joint strategy available from: ftp://ftp.fao.org/docrep/fao/011/ajl37e/ajl37e00.pdf). The 2008 FAO-OIE-WHO Joint Technical Consultation on Avian Influenza at the Human Animal Interface described here was the first opportunity for a large group of influenza experts from the animal and public health sectors to gather and discuss purely technical topics of joint interest that exist at the human-animal interface. During the consultation, three influenza-specific sessions aimed to (1) identify virological characteristics of avian influenza viruses (AIVs) important for zoonotic and pandemic disease, (2) evaluate the factors affecting evolution and emergence of a pandemic influenza strain and identify existing monitoring systems, and (3) identify modes of transmission and exposure sources for human zoonotic influenza infection (including discussion of specific exposure risks by affected countries). A

  6. Technical development of PubMed Interact: an improved interface for MEDLINE/PubMed searches

    PubMed Central

    Muin, Michael; Fontelo, Paul

    2006-01-01

    Background The project aims to create an alternative search interface for MEDLINE/PubMed that may provide assistance to the novice user and added convenience to the advanced user. An earlier version of the project was the 'Slider Interface for MEDLINE/PubMed searches' (SLIM) which provided JavaScript slider bars to control search parameters. In this new version, recent developments in Web-based technologies were implemented. These changes may prove to be even more valuable in enhancing user interactivity through client-side manipulation and management of results. Results PubMed Interact is a Web-based MEDLINE/PubMed search application built with HTML, JavaScript and PHP. It is implemented on a Windows Server 2003 with Apache 2.0.52, PHP 4.4.1 and MySQL 4.1.18. PHP scripts provide the backend engine that connects with E-Utilities and parses XML files. JavaScript manages client-side functionalities and converts Web pages into interactive platforms using dynamic HTML (DHTML), Document Object Model (DOM) tree manipulation and Ajax methods. With PubMed Interact, users can limit searches with JavaScript slider bars, preview result counts, delete citations from the list, display and add related articles and create relevance lists. Many interactive features occur at client-side, which allow instant feedback without reloading or refreshing the page resulting in a more efficient user experience. Conclusion PubMed Interact is a highly interactive Web-based search application for MEDLINE/PubMed that explores recent trends in Web technologies like DOM tree manipulation and Ajax. It may become a valuable technical development for online medical search applications. PMID:17083729

  7. Photophysics and photoredox processes at polymer-water interfaces. Final technical report

    SciTech Connect

    Webber, S.E.

    1998-11-01

    The transduction of light into chemical potential has been actively studies via a variety of mechanisms. Perhaps the most actively pursued approach is via photoredox chemistry. In this project, the authors have used hydrophobic polymer-water interfaces to investigate mechanisms. The paper discusses results on the effect of adsorbing polymers onto latex particles and the use of diblock amphiphilic polymers with interfacial chromophores. It then evaluates the project from the point of view of solar energy conversion.

  8. Improved Management of the Technical Interfaces Between the Hanford Tank Farm Operator and the Hanford Waste Treatment Plant - 13383

    SciTech Connect

    Duncan, Garth M.; Saunders, Scott A.

    2013-07-01

    The Department of Energy (DOE) is constructing the Waste Treatment and Immobilization Plant (WTP) at the Hanford site in Washington to treat and immobilize approximately 114 million gallons of high level radioactive waste (after all retrievals are accomplished). In order for the WTP to be designed and operated successfully, close coordination between the WTP engineering, procurement, and construction contractor, Bechtel National, Inc. and the tank farms operating contractor (TOC), Washington River Protection Solutions, LLC, is necessary. To develop optimal solutions for DOE and for the treatment of the waste, it is important to deal with the fact that two different prime contractors, with somewhat differing contracts, are tasked with retrieving and delivering the waste and for treating and immobilizing that waste. The WTP and the TOC have over the years cooperated to manage the technical interface. To manage what is becoming a much more complicated interface as the WTP design progresses and new technical issues have been identified, an organizational change was made by WTP and TOC in November of 2011. This organizational change created a co-located integrated project team (IPT) to deal with mutual and interface issues. The Technical Organization within the One System IPT includes employees from both TOC and WTP. This team has worked on a variety of technical issues of mutual interest and concern. Technical issues currently being addressed include: - The waste acceptance criteria; - Waste feed delivery and the associated data quality objectives (DQO); - Evaluation of the effects of performing a riser cut on a single shell tank on WTP operations; - The disposition of secondary waste from both TOC and WTP; - The close coordination of the TOC double shell tank mixing and sampling program and the Large Scale Integrated Test (LSIT) program for pulse jet mixers at WTP along with the associated responses to the Defense Nuclear Facilities Safety Board (DNFSB) Recommendation

  9. 'Buildings in Use' Study. Technical Factors.

    ERIC Educational Resources Information Center

    Wisconsin Univ., Milwaukee. School of Architecture and Urban Planning.

    The second report of the 'Buildings in Use' study documents the results of over 100 field tests conducted at four elementary schools, as well as discussion of these results and relevant technical specifications and details. The procedural framework used in the Field Tests Manual is followed and test results are rated numerically wherever possible.…

  10. Occupational-Technical Curriculum Development TV Study.

    ERIC Educational Resources Information Center

    McClure, Lyndon

    Section I of this report provides a brief review of various experiments and studies conducted in the United States and abroad on the effectiveness of televised occupational-technical courses. Issues discussed include the packaging of televised instruction; the need for preproduction testing; the limitations of television teaching; teacher and…

  11. Technical Issues Map for the NHI System Interface and Support Systems Area: 1st Quarter FY 07

    SciTech Connect

    Steven R. Sherman

    2006-12-01

    This document provides a mapping of technical issues associated with development of the Next Generation Nuclear Plant (NGNP) intermediate heat transport loop and nuclear hydrogen plant support systems to the work that has been accomplished or is currently underway. The technical issues are ranked according to priority and by assumed resolution dates. Due to funding limitations, not all high-priority technical issues are under study at the present time, and more resources will need to be dedicated to tackling such issues in the future. This technical issues map is useful for understanding the relative importance of various technical challenges and will be used as a planning tool for future work package planning.

  12. Dynamics explorer: Interface definition study, volume 1

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Work done in response to the work statement wherein a specific deliverable was not identified but where design and analysis tasks were identified is reported. The summary and baseline change list is included along with design notes for the spacecraft system, thermal subsystem, power subsystem, communications subsystem, plasma wave instrument interface definition, and the structure.

  13. Advanced human-system interface design review guideline. General evaluation model, technical development, and guideline description

    SciTech Connect

    O`Hara, J.M.

    1994-07-01

    Advanced control rooms will use advanced human-system interface (HSI) technologies that may have significant implications for plant safety in that they will affect the operator`s overall role in the system, the method of information presentation, and the ways in which operators interact with the system. The U.S. Nuclear Regulatory Commission (NRC) reviews the HSI aspects of control rooms to ensure that they are designed to good human factors engineering principles and that operator performance and reliability are appropriately supported to protect public health and safety. The principal guidance available to the NRC, however, was developed more than ten years ago, well before these technological changes. Accordingly, the human factors guidance needs to be updated to serve as the basis for NRC review of these advanced designs. The purpose of this project was to develop a general approach to advanced HSI review and the human factors guidelines to support NRC safety reviews of advanced systems. This two-volume report provides the results of the project. Volume I describes the development of the Advanced HSI Design Review Guideline (DRG) including (1) its theoretical and technical foundation, (2) a general model for the review of advanced HSIs, (3) guideline development in both hard-copy and computer-based versions, and (4) the tests and evaluations performed to develop and validate the DRG. Volume I also includes a discussion of the gaps in available guidance and a methodology for addressing them. Volume 2 provides the guidelines to be used for advanced HSI review and the procedures for their use.

  14. Guide to the stand-damage model interface management system. Forest Service general technical report (Final)

    SciTech Connect

    Racin, G.; Colbert, J.J.

    1995-08-16

    Describes the Gypsy Moth Stand-Damage interface management system. Management of stand-damage data made it necessary to define structures to store data and provide the mechanisms to manipulate these data. The software is used to manipulate files, graph and manage outputs, and edit input data. The interface was built using pop-up windows, menuing systems, text editing and validation, mouse support, and context-sensitive help. The interface is written in the C language for DOS microcomputers.

  15. Micro-engineered cathode interface studies

    SciTech Connect

    Doshi, R.; Kueper, T.; Nagy, Z.; Krumpelt, M.

    1997-08-01

    The aim of this work is to increase the performance of the cathode in solid oxide fuel cells (SOFCs) operating at 1,000 C by decreasing the polarization resistance from 0.2 {Omega}-cm{sup 2} at 300 mA/cm{sup 2}. Decreased polarization resistance will allow operation at higher current densities. This work is in support of the Westinghouse tubular SOFC technology using YSZ electrolyte and strontium doped lanthanum manganite (LSM) cathode. As a result of work performed last year at Argonne National Laboratory and information derived from the literature, the limitations at the cathode/electrolyte interface can be classified into two main areas. First, the ionic conductivity of the LSM cathode material is low which limits the reaction zone to an area very close to the interface, while the rest of the cathode thickness acts essentially as current collector with channels for gas access. Second, the electronic conductivity in YSZ is very low which limits the reaction zone to areas that are the boundaries between LSM and YSZ rather than the YSZ surface away from LSM at the interface. Possible solutions to this problem being pursued are: (1) introducing an ionic conducting YSZ phase in LSM to form a porous two-phase mixture of LSM and YSZ; (2) applying a thin interlayer between the electrolyte and the cathode where the interlayer has high ionic and electronic conductivity and high catalytic activity for reduction of O{sub 2}; (3) increasing the ionic conductivity in the LSM by suitable doping; and (4) increasing the electronic conductivity in the electrolyte by doping or by depositing an appropriate mixed conducting layer on the YSZ before applying the cathode.

  16. [A new human machine interface in neurosurgery: The Leap Motion(®). Technical note regarding a new touchless interface].

    PubMed

    Di Tommaso, L; Aubry, S; Godard, J; Katranji, H; Pauchot, J

    2016-06-01

    Currently, cross-sectional imaging viewing is used in routine practice whereas the surgical procedure requires physical contact with an interface (mouse or touch-sensitive screen). This type of contact results in a risk of lack of aseptic control and causes loss of time. The recent appearance of devices such as the Leap Motion(®) (Leap Motion society, San Francisco, USA) a sensor which enables to interact with the computer without any physical contact is of major interest in the field of surgery. However, its configuration and ergonomics produce key challenges in order to adapt to the practitioner's requirements, the imaging software as well as the surgical environment. This article aims to suggest an easy configuration of the Leap Motion(®) in neurosurgery on a PC for an optimized utilization with Carestream(®) Vue PACS v11.3.4 (Carestream Health, Inc., Rochester, USA) using a plug-in (to download at: https://drive.google.com/?usp=chrome_app#folders/0B_F4eBeBQc3ybElEeEhqME5DQkU) and a video tutorial (https://www.youtube.com/watch?v=yVPTgxg-SIk). PMID:27234915

  17. Scientist/AMPS equipment interface study

    NASA Technical Reports Server (NTRS)

    Anderson, H. R.

    1977-01-01

    The principal objective was to determine for each experiment how the operating procedures and modes of equipment onboard shuttle can be managed in real-time or near-real-time to enhance the quality of results. As part of this determination the data and display devices that a man will need for real-time management are defined. The secondary objectives, as listed in the RFQ and technical proposal, were to: (1) determine what quantities are to be measured (2) determine permissible background levels (3) decide in what portions of space measurements are to be made (4) estimate bit rates (5) establish time-lines for operating the experiments on a mission or set of missions and (6) determine the minimum set of hardware needed for real-time display. Experiment descriptions and requirements were written. The requirements of the various experiments are combined and a minimal set of joint requirements are defined.

  18. The interface of CCD image line sensor ILX511 in technical spectrometer

    NASA Astrophysics Data System (ADS)

    BartonÄk, LudÄk.; Keprt, Jiri, Sr.

    2003-11-01

    This paper presents a way for practical use of the CCD linear image sensor for scanning of light in some optical applications (spectroscopy). Communication of the equipment (detector CCD) with computer is realized by the help of a parallel interface of a personal computer (PC) without additive interface card. In final part of this contribution is presented a realization of measuring circuit (enhanced parallel interface PC) for the sensor ILXS 1 1. The use of the line detector is demonstrated on detection of the optical spectrum of the mercury lamp.

  19. Context-aware brain-computer interfaces: exploring the information space of user, technical system and environment

    NASA Astrophysics Data System (ADS)

    Zander, T. O.; Jatzev, S.

    2012-02-01

    Brain-computer interface (BCI) systems are usually applied in highly controlled environments such as research laboratories or clinical setups. However, many BCI-based applications are implemented in more complex environments. For example, patients might want to use a BCI system at home, and users without disabilities could benefit from BCI systems in special working environments. In these contexts, it might be more difficult to reliably infer information about brain activity, because many intervening factors add up and disturb the BCI feature space. One solution for this problem would be adding context awareness to the system. We propose to augment the available information space with additional channels carrying information about the user state, the environment and the technical system. In particular, passive BCI systems seem to be capable of adding highly relevant context information—otherwise covert aspects of user state. In this paper, we present a theoretical framework based on general human-machine system research for adding context awareness to a BCI system. Building on that, we present results from a study on a passive BCI, which allows access to the covert aspect of user state related to the perceived loss of control. This study is a proof of concept and demonstrates that context awareness could beneficially be implemented in and combined with a BCI system or a general human-machine system. The EEG data from this experiment are available for public download at www.phypa.org. Parts of this work have already been presented in non-journal publications. This will be indicated specifically by appropriate references in the text.

  20. Experimental study of interface properties between layer and substrate

    NASA Astrophysics Data System (ADS)

    Ko, Ray T.; Nagy, Peter B.; Adler, Laszlo

    A meshed intervening layer technique which makes it possible to study the interface properties between layer and substrate is presented. It is argued that the bonding condition of the interface can be monitored through the variation of the phase velocity of the modified Rayleigh mode. The experimental setup of the measurement of the reflection of ultrasonic waves from a layered substrate specimen is shown, and the frequency spectra from three typical bonding cases - perfectly bonded, partially bonded, and completely misbonded - are illustrated.

  1. Magnetic multilayer interface anisotropy. Technical progress report, January 1, 1992--December 31, 1992

    SciTech Connect

    Pechan, M.J.

    1992-12-01

    Ni/Mo and Ni/V multilayer magnetic anisotropy has been investigated as a function of Ni layer thickness, frequency and temperature. Variable frequency ferromagnetic resonance (FMR) measurements show, for the first time, significant frequency dependence associated with the multilayer magnetic anisotropy. The thickness dependence allows one to extract the interface contribution from the total anisotropy. Temperature dependent FMR (9 GHz) and room temperature magnetization indicate that strain between Ni and the non-magnetic layers is contributing significantly to the source of the interface anisotropy and the state of the interfacial magnetization. In order to examine the interface properties of other transition metal multilayer systems, investigations on Fe/Cu are underway and CoCr/Ag is being proposed. ESR measurements have been reported on Gd substituted YBaCuO superconductors and a novel quasi-equilibrium method has been developed to determine quickly and precisely the ransition temperature.

  2. Study of GaAs-oxide interface by transient capacitance spectroscopy - Discrete energy interface states

    NASA Technical Reports Server (NTRS)

    Kamieniecki, E.; Kazior, T. E.; Lagowski, J.; Gatos, H. C.

    1980-01-01

    Interface states and bulk GaAs energy levels were simultaneously investigated in GaAs MOS structures prepared by anodic oxidation. These two types of energy levels were successfully distinguished by carrying out a comparative analysis of deep level transient capacitance spectra of the MOS structures and MS structures prepared on the same samples of epitaxially grown GaAs. The identification and study of the interface states and bulk levels was also performed by investigating the transient capacitance spectra as a function of the filling pulse magnitude. It was found that in the GaAs-anodic oxide interface there are states present with a discrete energy rather than with a continuous energy distribution. The value of the capture cross section of the interface states was found to be 10 to the 14th to 10 to the 15th/sq cm, which is more accurate than the extremely large values of 10 to the -8th to 10 to the -9th/sq cm reported on the basis of conductance measurements.

  3. Evaluation Study of VTAE Wood Technics Programs.

    ERIC Educational Resources Information Center

    Wisconsin State Board of Vocational, Technical, and Adult Education, Madison.

    A survey of former students of the Wisconsin Vocational, Technical, and Adult Education (VTAE) wood technics programs and employers in woodworking industries was conducted during spring of 1985. General objectives were to determine job classifications, types of businesses, and relative importance of tasks or duties in various woodworking-related…

  4. Space Weather Studies at Istanbul Technical University

    NASA Astrophysics Data System (ADS)

    Kaymaz, Zerefsan

    2016-07-01

    This presentation will introduce the Upper Atmosphere and Space Weather Laboratory of Istanbul Technical University (ITU). It has been established to support the educational needs of the Faculty of Aeronautics and Astronautics in 2011 to conduct scientific research in Space Weather, Space Environment, Space Environment-Spacecraft Interactions, Space instrumentation and Upper Atmospheric studies. Currently the laboratory has some essential infrastructure and the most instrumentation for ionospheric observations and ground induced currents from the magnetosphere. The laboratory has two subunits: SWIFT dealing with Space Weather Instrumentation and Forecasting unit and SWDPA dealing with Space Weather Data Processing and Analysis. The research area covers wide range of upper atmospheric and space science studies from ionosphere, ionosphere-magnetosphere coupling, magnetic storms and magnetospheric substorms, distant magnetotail, magnetopause and bow shock studies, as well as solar and solar wind disturbances and their interaction with the Earth's space environment. We also study the spacecraft environment interaction and novel plasma instrument design. Several scientific projects have been carried out in the laboratory. Operational objectives of our laboratory will be carried out with the collaboration of NASA's Space Weather Laboratory and the facilities are in the process of integration to their prediction services. Educational and research objectives, as well as the examples from the research carried out in our laboratory will be demonstrated in this presentation.

  5. Technical Aspects of Interfacing MUMPS to an External SQL Relational Database Management System

    PubMed Central

    Kuzmak, Peter M.; Walters, Richard F.; Penrod, Gail

    1988-01-01

    This paper describes an interface connecting InterSystems MUMPS (M/VX) to an external relational DBMS, the SYBASE Database Management System. The interface enables MUMPS to operate in a relational environment and gives the MUMPS language full access to a complete set of SQL commands. MUMPS generates SQL statements as ASCII text and sends them to the RDBMS. The RDBMS executes the statements and returns ASCII results to MUMPS. The interface suggests that the language features of MUMPS make it an attractive tool for use in the relational database environment. The approach described in this paper separates MUMPS from the relational database. Positioning the relational database outside of MUMPS promotes data sharing and permits a number of different options to be used for working with the data. Other languages like C, FORTRAN, and COBOL can access the RDBMS database. Advanced tools provided by the relational database vendor can also be used. SYBASE is an advanced high-performance transaction-oriented relational database management system for the VAX/VMS and UNIX operating systems. SYBASE is designed using a distributed open-systems architecture, and is relatively easy to interface with MUMPS.

  6. The Interface as a Working Environment: A Purpose for Physical Geography. Geographic Technical Paper Series.

    ERIC Educational Resources Information Center

    Carter, Douglas B.; And Others

    This technical paper offers an alternative method to the traditional physical geography course which has as its primary objective the knowing of approved body of knowledge. The premise is that a discipline of physical geography does not now exist and that traditional physical geography consists of nearly independent topics treated without common…

  7. Capital projects: Egypt case study. Technical report

    SciTech Connect

    Lieberson, J.; Stallard, J.

    1994-03-01

    This report assesses the US Agency for International Development`s (A.I.D.`s) capital assistance program in Egypt in terms of both its commercial benefits for the United States and its developmental benefits for Egypt. In regard to the first aspect, the study found that few A.I.D.-funded projects or studies generated either participation by other donors or follow-on sales for U.S. companies. The report places much of the blame for this on U.S. firms` failure to take advantage of a clear opportunity to develop the Egyptian commercial market. Findings regarding the developmental benefits of the projects are mixed. (1) The projects helped support strong private sector growth in Egypt through the 1980`s. Nonetheless, their economic and financial rates of return were generally disappointing. (2) The projects were built to a high technical standard, but their sustainability is in doubt. (3) The pursuit of commercial advantage for U.S. firms did not distort the developmental goals of the projects. Overall, the report attributes the disappointing economic results of A.I.D.`s capital assistance program to a poor policy environment, which the reforms pursued in connection with the program did little to change.

  8. Interfaces in polymer nanocomposites - An NMR study

    NASA Astrophysics Data System (ADS)

    Böhme, Ute; Scheler, Ulrich

    2016-03-01

    Nuclear Magnetic Resonance (NMR) is applied for the investigation of polymer nanocomposites. Solid-state NMR is applied to study the modification steps to compatibilize layered double hydroxides with non-polar polymers. 1H relaxation NMR gives insight on the polymer dynamics over a wide range of correlation times. For the polymer chain dynamics the transverse relaxation time T2 is most suited. In this presentation we report on two applications of T2 measurements under external mechanical stress. In a low-field system relaxation NMR studies are performed in-situ under uniaxial stress. High-temperature experiments in a Couette cell permit the investigation of the polymer dynamics in the melt under shear flow.

  9. Man-machine systems of the 1990 decade: cognitive factors and human interface issues. Technical report

    SciTech Connect

    Hoffman, P.J.

    1985-08-01

    The primary psychological concepts fundamental to the design of man-machine interfaces for intelligent systems of the 1990's are presented. These concepts embrace perception, learning motivation, and cognitive capacities of human operators, in systems that require a high degree of operator-machine interaction. The central role of feedback is emphasized through simple schematic examples, designed to provide an understanding of the reciprocity requirements in man-machine communication. Cognitive theory and recent experimental data form the basis for discussion of visual image storage, short-term memory, long-term memory, transfer rates and buffering of information being processed by the human operator, under control of a central processor with a cycle time of roughly 70 milliseconds. Systems of the 1990 era will provide increased capability for high-speed processing of data and will utilize increasing numbers of decision-aides, spreadsheets and AI tools. Users of these systems will be components of networks, linked via efficient communication systems to other users and other subsystems. These developments will lead to fundamental changes in the work place. Keywords: Interface; Artificial Intelligence; Systems; Feedback; Productivity; User Interface; Man-Machine; Cognitive.

  10. Hydrogen energy systems studies. Final technical report

    SciTech Connect

    Ogden, J.M.; Kreutz, T.; Kartha, S.; Iwan, L.

    1996-08-13

    The results of previous studies suggest that the use of hydrogen from natural gas might be an important first step toward a hydrogen economy based on renewables. Because of infrastructure considerations (the difficulty and cost of storing, transmitting and distributing hydrogen), hydrogen produced from natural gas at the end-user`s site could be a key feature in the early development of hydrogen energy systems. In the first chapter of this report, the authors assess the technical and economic prospects for small scale technologies for producing hydrogen from natural gas (steam reformers, autothermal reformers and partial oxidation systems), addressing the following questions: (1) What are the performance, cost and emissions of small scale steam reformer technology now on the market? How does this compare to partial oxidation and autothermal systems? (2) How do the performance and cost of reformer technologies depend on scale? What critical technologies limit cost and performance of small scale hydrogen production systems? What are the prospects for potential cost reductions and performance improvements as these technologies advance? (3) How would reductions in the reformer capital cost impact the delivered cost of hydrogen transportation fuel? In the second chapter of this report the authors estimate the potential demand for hydrogen transportation fuel in Southern California.

  11. Computer modelling studies of the bilayer/water interface.

    PubMed

    Pasenkiewicz-Gierula, Marta; Baczynski, Krzysztof; Markiewicz, Michal; Murzyn, Krzysztof

    2016-10-01

    This review summarises high resolution studies on the interface of lamellar lipid bilayers composed of the most typical lipid molecules which constitute the lipid matrix of biomembranes. The presented results were obtained predominantly by computer modelling methods. Whenever possible, the results were compared with experimental results obtained for similar systems. The first and main section of the review is concerned with the bilayer-water interface and is divided into four subsections. The first describes the simplest case, where the interface consists only of lipid head groups and water molecules and focuses on interactions between the lipid heads and water molecules; the second describes the interface containing also mono- and divalent ions and concentrates on lipid-ion interactions; the third describes direct inter-lipid interactions. These three subsections are followed by a discussion on the network of direct and indirect inter-lipid interactions at the bilayer interface. The second section summarises recent computer simulation studies on the interactions of antibacterial membrane active compounds with various models of the bacterial outer membrane. This article is part of a Special Issue entitled: Biosimulations edited by Ilpo Vattulainen and Tomasz Róg. PMID:26825705

  12. Electron Microscopy Studies of Solid Surfaces and Interfaces.

    NASA Astrophysics Data System (ADS)

    Gajdardziska-Josifovska, Marija

    1991-02-01

    Electron microscopy techniques for study of surfaces and interfaces have been investigated and applied to (100) and (111) surfaces of MgO and to interfaces of Mo/Si multilayers and CoSi_2/Si epitaxial films. MgO surfaces subjected to different annealing and chemical treatments have been characterized by reflection electron microscopy imaging, reflection high-energy electron diffraction (RHEED), and reflection electron energy-loss spectroscopy (REELS). An oxygen rich (sqrt {3} times sqrt{3})R 30^circ reconstruction was found on the polar (111) surface upon annealing in oxygen at temperatures higher than 1500 ^circC. Transformation of the surface topography and segregation of calcium were observed on the cleaved (100) surface due to annealing. RHEED resonance conditions have been employed and studied with geometrical constructions, rocking curves and REELS. These conditions are associated with parabolas in the Kikuchi (K) patterns whose nature had been subject of much controversy. The parabolas have been explained as K lines of two-dimensional (2D) lattices in a general scheme which describes the K pattern geometry in terms of intersections of Brillouin zone boundaries with a sphere of reflections. Full treatment of the cases of 2D and 1D real lattices has revealed previously unknown boundaries in the form of parabolic surfaces (2D) and paraboloids of revolution (1D). These boundaries have been applied to lines which arise from electron channeling in 3D crystals and to RHEED parabolas from 2D surface reconstructions. Nanodiffraction, low angle dark-field imaging, electron holography, high spatial resolution EELS, and shadow imaging have been evaluated as means for measuring interface abruptness and change in mean-inner potential and compared to other microscopy techniques. Refraction effects at interfaces were observed as streaking of the nanodiffraction disks which was found to depend on the crystalline nature of the interface. For polycrystalline

  13. Technical operations and data collection details of the in situ WIPP (Waste Isolation Pilot Plant) Materials Interface Interaction Test

    SciTech Connect

    Molecke, M.A.

    1988-01-01

    The WIPP Materials Interface Interaction Tests (MIIT) experiments involve the in situ testing of multiple ''pineapple-slice'' shaped samples of simulated (nonradioactive) waste glasses, potential canister and overpack metals, brine, and rock salt in the salt repository environment at WIPP. This series of experiments involves multiple emplacements of various US and foreign glass waste forms (all nonradioactive) in contact with/interacting with several container metals, rock salt, brine, etc., all maintained at approximately 90 /+-/ 5/degree/C. The focus of this paper is on the technical aspects and operations of the MIIT experimental program, including assorted repository-relevant observations and experience gathered after more than two years of in situ test operation. As such, this is primarily a descriptive ''hardware'' and test operations document; test data are presented in parallel documents. 12 refs., 1 fig.

  14. Where the lay and the technical meet: Using an anthropology of interfaces to explain persistent reproductive health disparities in West Africa.

    PubMed

    Jaffré, Yannick; Suh, Siri

    2016-05-01

    Despite impressive global investment in reproductive health programs in West Africa, maternal mortality remains unacceptably high and obstetric care is often inadequate. Fertility is among the highest in the world, while contraceptive prevalence remains among the lowest. This paper explores the social and technical dimensions of this situation. We argue that effective reproductive health programs require analyzing the interfaces between technical programs and the social logics and behaviors of health professionals and client populations. Significant gaps between health programs' goals and the behaviors of patients and health care professionals have been observed. While public health projects aim to manage reproduction, sexuality, fertility, and professional practices are regulated socially. Such projects may target technical practices, but access to care is greatly influenced by social norms and ethics. This paper shows how an empirical anthropology that investigates the social and technical interfaces of reproduction can contribute to improved global health. PMID:27043370

  15. Comprehensive Study of High-Tc Interface Superconductivity

    SciTech Connect

    Logvenov, G.; Gozar A.; Butko, V.Y.; Bollinger, A.T.; Bozovic, N.; Radovic, Z.; Bozovic, I.

    2010-08-01

    Using ALL-MBE technique, we have synthesized different heterostructures consisting of an insulator La{sub 2}CuO{sub 4} (I) and a metal La{sub 1.56}Sr{sub 0.44}CuO{sub 4} (M) layer neither of which is superconducting by itself. The M-I bilayers were superconducting with a critical temperature T{sub c} {approx} 30-36 K. This highly robust phenomenon is confined within 1-2 nm from the interface and is primarily caused by the redistribution of doped holes across the interface. In this paper, we present a comprehensive study of the interface superconductivity by a range of experimental techniques including transport measurements of superconducting properties.

  16. Programs of Study: Year 2 Joint Technical Report. Research Snapshot

    ERIC Educational Resources Information Center

    National Research Center for Career and Technical Education, 2010

    2010-01-01

    In January 2010, the National Research Center for Career and Technical Education (NRCCTE) issued a progress report on three studies being conducted by the Center that examine the implementation and outcomes of Programs of Study (POS), which were required in the 2006 reauthorization of the federal legislation for career and technical education…

  17. Maintenance support: case study for a multimodal mobile user interface

    NASA Astrophysics Data System (ADS)

    Fuchs, G.; Reichart, D.; Schumann, H.; Forbrig, P.

    2006-02-01

    Maintaining and repairing complex technical facilities such as generating plants requires comprehensive knowledge on subsystems, operational and safety procedures by the technician. Upgrades to the facility may mean that knowledge about these becomes outdated, raising the need for documentation at the working site. Today's commonplace availability of mobile devices motivates the use of digital, interactive manuals over printed ones. Such applications should provide high-quality illustrations and interaction techniques tailored for specific tasks, while at the same time allow flexible deployment of these components on a multitude of (mobile) hardware platforms. This includes the integration of multimodal interaction facilities like speech recognition into the user interface. To meet these demands, we propose a model-based approach that combines task, object and dialog models to specify platform-independent user interfaces. New concepts like relating tasks to domain objects and dialog views allow us to generate abstract canonical prototypes. Another focus is on the necessary adaptation of visual representations to the platform capabilities to remain effective and adequate, requiring tight coupling of the underlying model, the visualization, and alternative input/output modes. The above aspects have been addressed in a prototype for air-condition unit maintenance, presented on the CeBIT 2005 fair.

  18. The Oregon Career and Technical Education Study

    ERIC Educational Resources Information Center

    Klein, Steven; Richards, Amanda

    2008-01-01

    Oregon educators, policymakers, and business people are working together to increase the number and quality of Career and Technical Education (CTE) programs in secondary and postsecondary institutions. CTE is an integral component of Oregon's education and workforce development system and prepares students for careers in areas ranging from the…

  19. Technical Studies Lead to Dream Career

    ERIC Educational Resources Information Center

    Suraci, Gary

    2008-01-01

    Like many young men, Ty Kropp had no idea what he wanted to do when he graduated from high school. Courses he took as a computer design/manufacturing (CDM) technology student at the Ulster County Career and Technical Education center in Port Ewen, NY, gave him valuable skills that opened the door to his dream job at Orange County Choppers (OCC), a…

  20. BBN technical memorandum W1291 infrasound model feasibility study

    SciTech Connect

    Farrell, T., BBN Systems and Technologies

    1998-05-01

    The purpose of this study is to determine the need and level of effort required to add existing atmospheric databases and infrasound propagation models to the DOE`s Hydroacoustic Coverage Assessment Model (HydroCAM) [1,2]. The rationale for the study is that the performance of the infrasound monitoring network will be an important factor for both the International Monitoring System (IMS) and US national monitoring capability. Many of the technical issues affecting the design and performance of the infrasound network are directly related to the variability of the atmosphere and the corresponding uncertainties in infrasound propagation. It is clear that the study of these issues will be enhanced by the availability of software tools for easy manipulation and interfacing of various atmospheric databases and infrasound propagation models. In addition, since there are many similarities between propagation in the oceans and in the atmosphere, it is anticipated that much of the software infrastructure developed for hydroacoustic database manipulation and propagation modeling in HydroCAM will be directly extendible to an infrasound capability. The study approach was to talk to the acknowledged domain experts in the infrasound monitoring area to determine: 1. The major technical issues affecting infrasound monitoring network performance. 2. The need for an atmospheric database/infrasound propagation modeling capability similar to HydroCAM. 3. The state of existing infrasound propagation codes and atmospheric databases. 4. A recommended approach for developing the required capabilities. A list of the people who contributed information to this study is provided in Table 1. We also relied on our knowledge of oceanographic and meteorological data sources to determine the availability of atmospheric databases and the feasibility of incorporating this information into the existing HydroCAM geographic database software. This report presents a summary of the need for an integrated

  1. Airborne Precision Spacing for Dependent Parallel Operations Interface Study

    NASA Technical Reports Server (NTRS)

    Volk, Paul M.; Takallu, M. A.; Hoffler, Keith D.; Weiser, Jarold; Turner, Dexter

    2012-01-01

    This paper describes a usability study of proposed cockpit interfaces to support Airborne Precision Spacing (APS) operations for aircraft performing dependent parallel approaches (DPA). NASA has proposed an airborne system called Pair Dependent Speed (PDS) which uses their Airborne Spacing for Terminal Arrival Routes (ASTAR) algorithm to manage spacing intervals. Interface elements were designed to facilitate the input of APS-DPA spacing parameters to ASTAR, and to convey PDS system information to the crew deemed necessary and/or helpful to conduct the operation, including: target speed, guidance mode, target aircraft depiction, and spacing trend indication. In the study, subject pilots observed recorded simulations using the proposed interface elements in which the ownship managed assigned spacing intervals from two other arriving aircraft. Simulations were recorded using the Aircraft Simulation for Traffic Operations Research (ASTOR) platform, a medium-fidelity simulator based on a modern Boeing commercial glass cockpit. Various combinations of the interface elements were presented to subject pilots, and feedback was collected via structured questionnaires. The results of subject pilot evaluations show that the proposed design elements were acceptable, and that preferable combinations exist within this set of elements. The results also point to potential improvements to be considered for implementation in future experiments.

  2. Studying Quality beyond Technical Rationality: Political and Symbolic Perspectives

    ERIC Educational Resources Information Center

    Blanco Ramírez, Gerardo

    2013-01-01

    The underlying paradigms that influence research on quality have remained alarmingly under-researched; this article analyses the constraints that a technical-rational approach for the study of quality in higher education imposes. Technical rationality has been the dominant paradigm that shapes research on quality in higher education.…

  3. Selling Technology in Technical Advertisements: A Case Study.

    ERIC Educational Resources Information Center

    Guthrie, James R.

    1995-01-01

    Argues that, as the category of "technical products" has expanded and the public's enthusiasm for such products has lessened, marketing writers have begun to reconsider their approaches to technology in ads. Studies two technical ads in detail, and compares the ways in which they portray technology. (SR)

  4. Career and Technical Education at a Crossroads: A Delphi Study

    ERIC Educational Resources Information Center

    Cutright, Michael W.

    2011-01-01

    Career and technical education in the United States has reached a critical juncture. A three round Delphi method was used to determine a consensus on the future events of career and technical education to better inform educational decision makers. Forty-one individual experts in the field were invited to serve as panelists for the Delphi study and…

  5. Nonlinear optical studies of aqueous interfaces, polymers, and nanowires

    NASA Astrophysics Data System (ADS)

    Onorato, Robert Michael

    Understanding the structure and composition of aqueous interfaces is one of the most important current problems in modern science. Aqueous interfaces are ubiquitous in Nature, ranging from aerosols to cellular structures. Aerosol chemistry is presently the most significant unknown factor in predicting climate change, and an understanding of the chemistry that occurs at aerosol interfaces would significantly improve climate models. Similarly, the nature of aqueous biological interfaces has a profound effect on the structure and function of proteins and other biological structures. Despite the importance of these problems, aqueous interfaces remain incompletely understood due to the challenges of experimentally probing them. Recent experimental and theoretical results have firmly established the existence of enhanced concentrations of selected ions at the air/water interface. In this dissertation, I use an interface-specific technique, UV second harmonic generation (SHG), to further investigate the adsorption of ions to the air/water interface and to extend the study of ion adsorption towards more biologically relevant systems, alcohol/water interfaces. In Chapter 2, I describe resonant UV-SHG studies of the strongly chaotropic thiocyanate ion adsorbed to the interface formed by water and a monolayer of dodecanol, wherein the Gibbs free energy of adsorption was determined to be -6.7 +/- 1.1 and -6.3 +/- 1.8 kJ/mol for sodium and potassium thiocyanate, respectively, coincident with the value determined for thiocyanate at the air/water interface. Interestingly, at concentrations near and above 4 M, the resonant SHG signal increases discontinuously, indicating a structural change in the interfacial region. Recent experimental and theoretical work has demonstrated that the adsorption of bromide is particularly important for chemical reactions on atmospheric aerosols, including the depletion of ozone. In Chapter 3, UV-SHG resonant with the bromide charge

  6. Exploration studies technical report, FY1988 status. Volume 1: Technical summary

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The Office of Exploration (OEXP) at NASA Headquarters has been tasked with defining and recommending alternatives for an early 1990's nationaL decision on a focused program of human exploration of the solar system. The Mission Analysis and System Engineering (MASE) group, which is managed by the Exploration Studies Office at the Lyndon B. Johnson Space Center, is responsible for coordinating the technical studies necessary for accomplishing such a task. This technical report, produced by the MASE, describes the process that has been developed in a case study approach. The four case studies developed in FY88 include: (1) Human Expedition to Phobos; (2) Human Expedition to Mars; (3) Lunar Observatory; and (4) Lunar Outpost to Early Mars Evolution. The final outcome of this effort is a set of programmatic and technical conclusions and recommendations for the following year's work.

  7. Respiration gated radiotherapy treatment: a technical study

    NASA Astrophysics Data System (ADS)

    Kubo, Hideo D.; Hill, Bruce C.

    1996-01-01

    In order to optimize external-beam conformal radiotherapy, patient movement during treatment must be minimized. For treatment on the upper torso, the target organs are known to move substantially due to patient respiration. This paper deals with the technical aspects of gating the radiotherapy beam synchronously with respiration: the optimal respiration monitoring system, measurements of organ displacement and linear accelerator gating. Several respiration sensors including a thermistor, a thermocouple, a strain gauge and a pneumotachograph were examined to find the optimal sensor. The magnitude of breast, chest wall and lung motion were determined using playback of fluoroscopic x-ray images recorded on a VCR during routine radiotherapy simulation. Total dose, beam symmetry and beam uniformity were examined to determine any effects on the Varian 2100C linear accelerator due to gating.

  8. Experimental study of the oscillating interface of a falling drop

    NASA Astrophysics Data System (ADS)

    Choi, Suhwan; Ward, Thomas

    2012-11-01

    The drop interface oscillation generated from detachment from a nozzle due to gravity are experimentally studied. The fluids used in the experiments are glycerol-water mixtures with viscosities ranging from 0.005 to 0.410 Pa s, mineral oil having a viscosity of 0.0270 Pa s, and DI water with viscosity of 0.0009 Pa s. The drop oscillating is taken by fast camera to make observations. For large drops, where the interface relative to a polar angle may be measured, the periodic deformation is plotted as a function of time. For smaller drops we measure the deformation as switching between an oblate and prolate drop as a function of time. The phenomenon is clearly a function of the fluid viscosity but we seek to propose a pinch-off mechanism for understanding the source of the observed oscillations.

  9. X-Ray Studies of Thin Films and Interfaces.

    NASA Astrophysics Data System (ADS)

    Woronick, Steven Charles

    1990-01-01

    Presented here are a series of x-ray studies utilizing synchrotron radiation to investigate a variety of properties of thin films and interfaces in technologically important materials. By far the largest part of this dissertation is devoted to studies of x-ray reflectivity as a function of angle (mainly soft x rays), although some extended x -ray absorption fine structure (EXAFS) results are included as reprinted published papers (briefly discussed). The reflectivity discussion covers theory, experimental techniques, data analysis (by curve-fitting), and specific applications. The material systems studied by the x-ray reflectivity technique include: bulk silicon, GaAs, InAs, ~250 -A InAs layers deposited by molecular-beam epitaxy (MBE) on GaAs(100) substrates, four thicknesses (~ 126-1100 A) of SiO_2 /Si(100) produced by dry thermal oxidation, and ~250-A layers of CoSi_2 /Si(111) (two samples, one produced by MBE and one by solid-phase epitaxy). Results determined from the reflectivity measurements include: interfacial roughness parameters, refractive index of materials (in the energy range ~400-1100 eV), and overlayer thicknesses. It has been found for example that the indium -stabilized growth mode of InAs on GaAs(100) results in a smoother buried interface than the arsenic-stabilized growth mode, while the indium-stabilized growth mode on 2^circ-off GaAs(100) produces the smoothest buried interface (with typical roughness parameters in the range 10-19 A). Preliminary results indicate that growth of CoSi_2/Si(111) by MBE produces smoother buried interfaces than growth by solid-phase epitaxy. The roughness parameters have been explained in terms of growth conditions, lattice mismatch, and material inhomogeneity in the vicinity of the buried interface. The oxygen atomic scattering factor for photons in the range 400-800 eV (oxygen K edge ~ 540 eV) has also been deduced from a determination the Si and SiO_2 refractive indices. The EXAFS studies were used to

  10. Atomistic study on the FCC/BCC interface structure with {112}KS orientation

    SciTech Connect

    Kang, Keonwook; Beyerlein, Irene; Han, Weizhong; Wang, Jian; Mara, Nathan

    2011-09-23

    In this study, atomistic simulation is used to explore the atomic interface structure, the intrinsic defect network, and mechanism of twin formation from the {112}KS Cu-Nb interface. The interface structure of different material systems AI-Fe and AI-Nb are also compared with Cu-Nb interface.

  11. Propagation of Stream Interfaces: An LFM-helio Study

    NASA Astrophysics Data System (ADS)

    Pahud, D. M.; Hughes, W.; Merkin, V. G.; McGregor, S. L.

    2012-12-01

    During the last solar minimum, the heliosphere was dominated by steady-state Stream Interaction Regions (SIRs). Carrington Rotation (CR) 2060, which occurred during this period, contained multiple SIRs and was free of transient phenomena which made it a good interval for the study of SIRs. We have used the Lyon-Fedder-Mobarry (LFM) heliospheric 3-D magnetohydrodynamic (MHD) model, the LFM-helio, to examine the radial evolution of SIRs, particularly the speed of the stream interface, from 0.1 AU to 2.0 AU. The LFM-helio is an adaptation of the magnetospheric LFM MHD code to heliospheric plasmas and fields. The ideal MHD equations are solved on a uniform spherical grid, excluding 10 degree cones centered at the poles. The inner boundary condition is obtained using the Wang-Sheeley-Arge (WSA) coronal model driven by photospheric magnetic field measurements for CR 2060. The global nature of the LFM-helio solution facilitates the study of the steepening of SIRs as well as their speed through the ambient plasma. For the SIR considered, the location of the stream interface is determined using multiple definitions, namely: the location of maximum total pressure, the location of maximum flow vorticity, the location of null azimuthal flow velocity and the location of steepest gradient of entropy. The speed of the plasma at these locations is compared to the mean speed of the interface to determine whether the interfaces are convected with the solar wind or propagate through it. In order to elucidate the physics of the evolution of the SIR, we also ran the LFM-helio using an idealized inner boundary condition. The idealized inner boundary specified the solar wind speed so as to ensure the presence of an SIR. Specifically, a source of fast wind was located at the same latitude as, and longitudinally near, a source of slow wind. The combined effect of radially outward plasma flow and rotation of the inner boundary align the fast wind behind the slow wind, creating an SIR. The

  12. 2008 ULTRASONIC BENCHMARK STUDIES OF INTERFACE CURVATURE--A SUMMARY

    SciTech Connect

    Schmerr, L. W.; Huang, R.; Raillon, R.; Mahaut, S.; Leymarie, N.; Lonne, S.; Spies, M.; Lupien, V.

    2009-03-03

    In the 2008 QNDE ultrasonic benchmark session researchers from five different institutions around the world examined the influence that the curvature of a cylindrical fluid-solid interface has on the measured NDE immersion pulse-echo response of a flat-bottom hole (FBH) reflector. This was a repeat of a study conducted in the 2007 benchmark to try to determine the sources of differences seen in 2007 between model-based predictions and experiments. Here, we will summarize the results obtained in 2008 and analyze the model-based results and the experiments.

  13. Video STM Studies of Adsorbate Diffusion at Electrochemical Interfaces

    NASA Astrophysics Data System (ADS)

    Tansel, T.; Magnussen, O. M.

    2006-01-01

    Direct in situ studies of the surface diffusion of isolated adsorbates at an electrochemical interface by high-speed scanning tunneling microscopy (video STM) are presented for sulfide adsorbates on Cu(100) in HCl solution. As revealed by a quantitative statistical analysis, the adsorbate motion can be described by thermally activated hopping between neighboring adsorption sites with an activation energy that increases linearly with electrode potential by 0.50 eV per V. This can be explained by changes in the adsorbate dipole moment during the hopping process and contributions from coadsorbates.

  14. Space station automation and robotics study. Operator-systems interface

    NASA Technical Reports Server (NTRS)

    1984-01-01

    This is the final report of a Space Station Automation and Robotics Planning Study, which was a joint project of the Boeing Aerospace Company, Boeing Commercial Airplane Company, and Boeing Computer Services Company. The study is in support of the Advanced Technology Advisory Committee established by NASA in accordance with a mandate by the U.S. Congress. Boeing support complements that provided to the NASA Contractor study team by four aerospace contractors, the Stanford Research Institute (SRI), and the California Space Institute. This study identifies automation and robotics (A&R) technologies that can be advanced by requirements levied by the Space Station Program. The methodology used in the study is to establish functional requirements for the operator system interface (OSI), establish the technologies needed to meet these requirements, and to forecast the availability of these technologies. The OSI would perform path planning, tracking and control, object recognition, fault detection and correction, and plan modifications in connection with extravehicular (EV) robot operations.

  15. Electrochemical impedance study of the hematite/water interface.

    PubMed

    Shimizu, Kenichi; Lasia, Andrzej; Boily, Jean-François

    2012-05-22

    Reactions taking place on hematite (α-Fe(2)O(3)) surfaces in contact with aqueous solutions are of paramount importance to environmental and technological processes. The electrochemical properties of the hematite/water interface are central to these processes and can be probed by open circuit potentials and cyclic voltammetric measurements of semiconducting electrodes. In this study, electrochemical impedance spectroscopy (EIS) was used to extract resistive and capacitive attributes of this interface on millimeter-sized single-body hematite electrodes. This was carried out by developing equivalent circuit models for impedance data collected on a semiconducting hematite specimen equilibrated in solutions of 0.1 M NaCl and NH(4)Cl at various pH values. These efforts produced distinct sets of capacitance values for the diffuse and compact layers of the interface. Diffuse layer capacitances shift in the pH 3-11 range from 2.32 to 2.50 μF·cm(-2) in NaCl and from 1.43 to 1.99 μF·cm(-2) in NH(4)Cl. Furthermore, these values reach a minimum capacitance at pH 9, near a probable point of zero charge for an undefined hematite surface exposing a variety of (hydr)oxo functional groups. Compact layer capacitances pertain to the transfer of ions (charge carriers) from the diffuse layer to surface hydroxyls and are independent of pH in NaCl, with values of 32.57 ± 0.49 μF·cm(-2)·s(-φ). However, they decrease with pH in NH(4)Cl from 33.77 at pH 3.5 to 21.02 μF·cm(-2)·s(-φ) at pH 10.6 because of the interactions of ammonium species with surface (hydr)oxo groups. Values of φ (0.71-0.73 in NaCl and 0.56-0.67 in NH(4)Cl) denote the nonideal behavior of this capacitor, which is treated here as a constant phase element. Because electrode-based techniques are generally not applicable to the commonly insulating metal (oxyhydr)oxides found in the environment, this study presents opportunities for exploring mineral/water interface chemistry by EIS studies of single

  16. Study of job burnout in technical writers and technical illustrators/designers at LLNL

    SciTech Connect

    Rice, J A

    1998-06-03

    According to the American Institute of Stress, job stress is estimated to cost American industry more than $200 billion a year. These costs are, in part, related to the estimated 1 million employees that will be absent on an average workday because of stress; 75 percent of visits to primary care physicians are for stress-related problems. California workers' compensation claims for stress cost $1 billion for medical and legal fees alone (Murphy, 1997). But, there is another dimension to stress that needs to be addressed. Job stress can be a precursor to job burnout. Burnout is a loss of motivation, and antidotes for job stress will not necessarily alleviate or stop job burnout. Job burnout is experienced as exhaustion on physical, emotional, and cognitive levels. Burnout can include withdrawal and decreasing involvement on the job, seriously affecting job satisfaction, turnover, absenteeism, and productivity (Dwyer & Ganster, 1991; Erickson & Gunderson, 1972; Spector & Jex, 1991). The research project described in this paper examined whether job burnout exists in the technical writer and technical illustrator/designer occupations in the Technical Information Department at Lawrence Livermore National Laboratory. This study also determined at what age and after how many years of service these employees were most likely to experience job burnout, whether it affects men or women most, and if writers in a technical organization experience job burnout more than illustrators/designers in that organization.

  17. 29 CFR 1607.14 - Technical standards for validity studies.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... study. Nothing in these guidelines is intended to preclude the development and use of other... technically feasible for a user to conduct a validity study, the user has the obligation otherwise to comply... information about the job. Any validity study should be based upon a review of information about the job...

  18. 29 CFR 1607.14 - Technical standards for validity studies.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... study. Nothing in these guidelines is intended to preclude the development and use of other... technically feasible for a user to conduct a validity study, the user has the obligation otherwise to comply... information about the job. Any validity study should be based upon a review of information about the job...

  19. 29 CFR 1607.14 - Technical standards for validity studies.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... study. Nothing in these guidelines is intended to preclude the development and use of other... technically feasible for a user to conduct a validity study, the user has the obligation otherwise to comply... information about the job. Any validity study should be based upon a review of information about the job...

  20. 29 CFR 1607.14 - Technical standards for validity studies.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... study. Nothing in these guidelines is intended to preclude the development and use of other... technically feasible for a user to conduct a validity study, the user has the obligation otherwise to comply... information about the job. Any validity study should be based upon a review of information about the job...

  1. 29 CFR 1607.14 - Technical standards for validity studies.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... study. Nothing in these guidelines is intended to preclude the development and use of other... technically feasible for a user to conduct a validity study, the user has the obligation otherwise to comply... information about the job. Any validity study should be based upon a review of information about the job...

  2. Ultrafast studies of electron dynamics at metal-dielectric interfaces

    SciTech Connect

    Ge, Nien-Hui

    1998-10-01

    Femtosecond time- and angle-resolved two-photon photoemission spectroscopy has been used to study fundamental aspects of excited electron dynamics at metal-dielectric interfaces, including layer-by-layer evolution of electronic structure and two-dimensional electron localization. On bare Ag(111), the lifetimes of image states are dominated by their position with respect to the projected bulk band structure. The n = 2 state has a shorter lifetime than the n = 1 state due to degeneracy with the bulk conduction band. As the parallel momentum of the n = 1 image electron increases, the lifetime decreases. With decreasing temperatures, the n = 1 image electrons, with zero or nonzero parallel momentum, all become longer lived. Adsorption of one to three layers of n-heptane results in an approximately exponential increase in lifetime as a function of layer thickness. This results from the formation of a tunneling barrier through which the interfacial electrons must decay, consistent with the repulsive bulk electron affinity of n-alkanes. The lifetimes of the higher quantum states indicate that the presence of the monolayer significantly reduces coupling of the image states to the bulk band structure. These results are compared with predictions of a dielectric continuum model. The study of electron lateral motion shows that optical excitation creates interfacial electrons in quasifree states for motion parallel to the n-heptane/Ag(111) interface. These initially delocalized electrons decay into a localized state within a few hundred femtoseconds. The localized electrons then decay back to the metal by tunneling through the adlayer potential barrier. The localization time depends strongly on the electron's initial parallel momentum and exhibits a non-Arrhenius temperature dependence. The experimental findings are consistent with a 2-D self-trapping process in which electrons become localized by interacting with the topmost plane of the alkane layer. The energy dependence of

  3. Elementary Staffing Study. Final Technical Report. Appendixes.

    ERIC Educational Resources Information Center

    Austin Independent School District, TX. Office of Research and Evaluation.

    The Elementary Staffing Study was conducted to develop a formula for determining the allocation of personnel positions and services for individual elementary school campuses in the Austin Independent School District. The 1981-82 study was meant to identify factors to be considered in personnel assignment, to "weight" each factor, and to use the…

  4. Vibrational spectroscopy of buried interfaces using nonlinear optics. Final technical report, July 7, 1986--February 29, 1996

    SciTech Connect

    Furtak, T.E.

    1996-05-30

    This DOE sponsored program has been dedicated to the understanding, development, and application of nontraditional methods for studying buried interfaces, particularly the electrolyte-solid system. Most of the work has dealt with optical techniques. The early research was directed toward revealing the mechanisms of surface enhanced Raman scattering (SERS). More recently the author has concentrated on surface nonlinear optical effects--second harmonic generation (SHG) and sum-frequency generation (SHG). Both of these techniques have the potential for selective interface sensitivity, and are produced through a higher order susceptibility than that which governs linear optical response. Optical SHG has the potential of providing more information about a buried interface than can be obtained by conventional optical spectroscopy. The author`s experiments have been designed to: (a) extract the second order optical susceptibility tensor associated with the surface of a metal electrode, and (b) discover how the electrochemical environment influences the nonlinear optical measurements. Recent contributions include quantitative comparison of the nonlinear response of single crystal silver to theoretical models for the effect. The author has provided the first detailed test of the time-dependent, local density functional prediction. Optical SHG bears a fundamental connection with the symmetry of the surface atoms. While investigating Ag(111) an anomalous effect was discovered that could not be explained by the known surface structure of Ag. The phenomenon was tentatively assigned to an adsorption induced surface reconstruction, since it behaved like a second order phase transition. In addition to the optical phenomena the author has designed, built, and operated an in situ quartz crystal microbalance (QCM) electrochemical cell.

  5. Supported Lipid Bilayer Technology for the Study of Cellular Interfaces

    PubMed Central

    Crites, Travis J.; Maddox, Michael; Padhan, Kartika; Muller, James; Eigsti, Calvin; Varma, Rajat

    2015-01-01

    Glass-supported lipid bilayers presenting freely diffusing proteins have served as a powerful tool for studying cell-cell interfaces, in particular, T cell–antigen presenting cell (APC) interactions, using optical microscopy. Here we expand upon existing protocols and describe the preparation of liposomes by an extrusion method, and describe how this system can be used to study immune synapse formation by Jurkat cells. We also present a method for forming such lipid bilayers on silica beads for the study of signaling responses by population methods, such as western blotting, flow cytometry, and gene-expression analysis. Finally, we describe how to design and prepare transmembrane-anchored protein-laden liposomes, following expression in suspension CHO (CHOs) cells, a mammalian expression system alternative to insect and bacterial cell lines, which do not produce mammalian glycosylation patterns. Such transmembrane-anchored proteins may have many novel applications in cell biology and immunology. PMID:26331983

  6. Cathode interface studies of polymer light emitting devices

    NASA Astrophysics Data System (ADS)

    Swiontek, Stephen; Tzolov, Marian

    2010-03-01

    Efficient injection of charge carriers is a key factor for successful operation of any electronic device and especially of devices with non-crystalline or wide band gap active material. Our study concentrates on the cathode interface of light emitting devices with a conjugated polymer as light emitter. We apply two principally different methods for the cathode deposition, physical and chemical, in order to fundamentally understand if in addition to the commonly accepted notion for the matching of the work functions also material modification takes place. The completed devices are studies by steady-state electrical measurements, impedance spectroscopy, current and emission lifetime measurements, and electroluminescence spectroscopy. The morphology of the cathodes is studied by Scanning Electron Microscopy and the formation of additional phases by Energy Dispersive X-ray Spectroscopy. The results help to define ways for more cost efficient fabrication of light emitting devices with applications in displays, electronic newspapers, room illumination, etc.

  7. Laser studies of chemical dynamics at the gas-solid interface

    NASA Astrophysics Data System (ADS)

    Cavanagh, Richard R.; King, David S.

    The DOE funded research program Laser Studies of Chemical Dynamics at the Gas-Solid Interface has taken a detailed, microscopic view of molecules desorbed from surfaces in order to gain an understanding of energy flow and interaction potentials and how these control chemical reactivity at interfaces. Successful completion of these experiments required technical expertise both in surface science and laser-based molecular dynamics, a collaborative situation that exists in the NIST center for Atomic, Molecular and Optical Physics. During the three year period covered by this progress report, our goal was to use state-resolved techniques to examine a single chemisorption system in detail, and to observe how changes in the interaction potential or method of surface excitation are manifest in the desorption dynamics. The system chosen was NO/Pt(111). Studies were undertaken in which the effects on the NO-Pt interaction potential of coadsorbates--both weakly (CO) and strongly (NH(sub 3)) interacting-- could be examined. In addition, attempts were to be made to study non- equilibrium dynamics by using pulsed laser heating.

  8. Body Machine Interfaces for Neuromotor Rehabilitation: a Case Study

    PubMed Central

    Pierella, Camilla; Abdollahi, Farnaz; Farshchiansadegh, Ali; Pedersen, Jessica; Chen, David; Mussa-Ivaldi, Ferdinando A.; Casadio, Maura

    2015-01-01

    High-level spinal cord injury (SCI) survivors face every day two related problems: recovering motor skills and regaining functional independence. Body machine interfaces (BoMIs) empower people with sever motor disabilities with the ability to control an external device, but they also offer the opportunity to focus concurrently on achieving rehabilitative goals. In this study we developed a portable, and low-cost BoMI that addresses both problems. The BoMI remaps the user’s residual upper body mobility to the two coordinates of a cursor on a computer monitor. By controlling the cursor, the user can perform functional tasks, such as entering text and playing games. This framework also allows the mapping between the body and the cursor space to be modified, gradually challenging the user to exercise more impaired movements. With this approach, we were able to change the behavior of our SCI subject, who initially used almost exclusively his less impaired degrees of freedom - on the left side - for controlling the BoMI. At the end of the few practice sessions he had restored symmetry between left and right side of the body, with an increase of mobility and strength of all the degrees of freedom involved in the control of the interface. This is the first proof of concept that our BoMI can be used to control assistive devices and reach specific rehabilitative goals simultaneously. PMID:25569980

  9. Body machine interfaces for neuromotor rehabilitation: a case study.

    PubMed

    Pierella, Camilla; Abdollahi, Farnaz; Farshchiansadegh, Ali; Pedersen, Jessica; Chen, David; Mussa-Ivaldi, Ferdinando A; Casadio, Maura

    2014-01-01

    High-level spinal cord injury (SCI) survivors face every day two related problems: recovering motor skills and regaining functional independence. Body machine interfaces (BoMIs) empower people with sever motor disabilities with the ability to control an external device, but they also offer the opportunity to focus concurrently on achieving rehabilitative goals. In this study we developed a portable, and low-cost BoMI that addresses both problems. The BoMI remaps the user's residual upper body mobility to the two coordinates of a cursor on a computer monitor. By controlling the cursor, the user can perform functional tasks, such as entering text and playing games. This framework also allows the mapping between the body and the cursor space to be modified, gradually challenging the user to exercise more impaired movements. With this approach, we were able to change the behavior of our SCI subject, who initially used almost exclusively his less impaired degrees of freedom - on the left side - for controlling the BoMI. At the end of the few practice sessions he had restored symmetry between left and right side of the body, with an increase of mobility and strength of all the degrees of freedom involved in the control of the interface. This is the first proof of concept that our BoMI can be used to control assistive devices and reach specific rehabilitative goals simultaneously. PMID:25569980

  10. Third International Mathematics and Science Study 1999 Video Study Technical Report: Volume 2--Science. Technical Report. NCES 2011-049

    ERIC Educational Resources Information Center

    Garnier, Helen E.; Lemmens, Meike; Druker, Stephen L.; Roth, Kathleen J.

    2011-01-01

    This second volume of the Third International Mathematics and Science Study (TIMSS) 1999 Video Study Technical Report focuses on every aspect of the planning, implementation, processing, analysis, and reporting of the science components of the TIMSS 1999 Video Study. The report is intended to serve as a record of the actions and documentation of…

  11. Third International Mathematics and Science Study 1999 Video Study Technical Report: Volume 1--Mathematics. Technical Report. NCES 2003-012

    ERIC Educational Resources Information Center

    Jacobs, Jennifer; Garnier, Helen; Gallimore, Ronald; Hollingsworth, Hilary; Givvin, Karen Bogard; Rust, Keith; Kawanaka, Takako; Smith, Margaret; Wearne, Diana; Manaster, Alfred; Etterbeek, Wallace; Hiebert, James; Stigler, James

    2003-01-01

    This first volume of the Third International Mathematics and Science Study (TIMSS) 1999 Video Study Technical Report focuses on every aspect of the planning, implementation, processing, analysis, and reporting of the mathematics components of the TIMSS 1999 Video Study. The report is intended to serve as a record of the actions and documentation…

  12. The CULTEX RFS: A Comprehensive Technical Approach for the In Vitro Exposure of Airway Epithelial Cells to the Particulate Matter at the Air-Liquid Interface

    PubMed Central

    Aufderheide, Michaela; Hochrainer, Dieter

    2013-01-01

    The EU Regulation on Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) demands the implementation of alternative methods for analyzing the hazardous effects of chemicals including particulate formulations. In the field of inhalation toxicology, a variety of in vitro models have been developed for such studies. To simulate the in vivo situation, an adequate exposure device is necessary for the direct exposure of cultivated lung cells at the air-liquid interface (ALI). The CULTEX RFS fulfills these requirements and has been optimized for the exposure of cells to atomized suspensions, gases, and volatile compounds as well as micro- and nanosized particles. This study provides information on the construction and functional aspects of the exposure device. By using the Computational Fluid Dynamics (CFD) analysis, the technical design was optimized to realize a stable, reproducible, and homogeneous deposition of particles. The efficiency of the exposure procedure is demonstrated by exposing A549 cells dose dependently to lactose monohydrate, copper(II) sulfate, copper(II) oxide, and micro- and nanoparticles. All copper compounds induced cytotoxic effects, most pronounced for soluble copper(II) sulfate. Micro- and nanosized copper(II) oxide also showed a dose-dependent decrease in the cell viability, whereby the nanosized particles decreased the metabolic activity of the cells more severely. PMID:23509768

  13. Closing the Gender Gap in Technical Disciplines: AN Investigative Study

    NASA Astrophysics Data System (ADS)

    Gokhale, Anu A.; Stier, Ken

    The goal of this study was to investigate the efficacy of curriculum and instructional techniques in a technical core course to create a more conducive learning environment for women. The technical core course introduced technology majors to mechanical systems, electronics, and fluid power principles through lectures and laboratory work. Female students already enrolled in the department and female alumnae of the program were surveyed. The students' responses to the survey showed that although the female participants in the study were pleased with the instructors, the curriculum, and the instruction they received, they had recommendations for modifying the instruction.

  14. Reusable Agena study. Volume 2: Technical

    NASA Technical Reports Server (NTRS)

    Carter, W. K.; Piper, J. E.; Douglass, D. A.; Waller, E. W.; Hopkins, C. V.; Fitzgerald, E. T.; Sagawa, S. S.; Carter, S. A.; Jensen, H. L.

    1974-01-01

    The application of the existing Agena vehicle as a reusable upper stage for the space shuttle is discussed. The primary objective of the study is to define those changes to the Agena required for it to function in the reusable mode in the 100 percent capture of the NASA-DOD mission model. This 100 percent capture is achieved without use of kick motors or stages by simply increasing the Agena propellant load by using optional strap-on-tanks. The required shuttle support equipment, launch and flight operations techniques, development program, and cost package are also defined.

  15. Adhesion at WC/diamond interfaces - A theoretical study

    SciTech Connect

    Padmanabhan, Haricharan; Rao, M. S. Ramachandra; Nanda, B. R. K.

    2015-06-24

    We investigate the adhesion at the interface of face-centered tungsten-carbide (001) and diamond (001) from density-functional calculations. Four high-symmetry model interfaces, representing different lattice orientations for either side of the interface, are constructed to incorporate different degrees of strain arising due to lattice mismatch. The adhesion, estimated from the ideal work of separation, is found to be in the range of 4 - 7 J m{sup −2} and is comparable to that of metal-carbide interfaces. Maximum adhesion occurs when WC and diamond slabs have the same orientation, even though such a growth induces large epitaxial strain at the interface. From electronic structure calculations, we attribute the adhesion to covalent interaction between carbon p-orbitals as well as partial ionic interaction between the tungsten d- and carbon p-orbitals across the interface.

  16. Space Tug Aerobraking Study. Volume 2: Technical

    NASA Technical Reports Server (NTRS)

    Corso, C. J.; Eyer, C. L.

    1972-01-01

    The feasibility and practicality of employing an aerobraking trajectory for return of the reusable Space Tug from geosynchronous and other high energy missions was investigated. The aerobraking return trajectory modes from high orbits employ transfer ellipses which have low perigee altitudes wherein the earth's sensible atmosphere provides drag to reduce the Tug descent delta velocity requirements and thus decrease the required return trip propulsive energy. An aerobraked Space Tug, sized to the Space Shuttle payload capability and dimensional constraints, can accomplish 95 percent of the geosynchronous missions with a single Shuttle/Tug launch per mission. Aerodynamics, aerothermodynamics, trajectory, quidance and control, configuration concepts, materials, weights and performance parameters were identified. Sensitivities to trajectory uncertainties, atmospheric anomalies and re-entry environments were determined. New technology requirements and future studies required to further enhance the aerobraking potential were identified.

  17. Drainage flows: A mountain-plains interface numerical case study

    SciTech Connect

    Poulos, G.S.; Bossert, J.E.

    1992-01-01

    In January/February, 1991 an intensive set of measurements was taken around Rocky Flats near Denver, CO, USA under the auspices of the Atmospheric Studies in Complex Terrain (ASCOT) program. This region of the country is known as the Front Range, and is characterized by a transition from the relatively flat terrain of the Great Plains to the highly varied terrain of the Rocky Mountains. The mountains are oriented north-south and rise from 1800m above mean sea level (MSL) to 3600m MSL at the Continental Divide. Numerous east-west oriented valleys begin in the mountains and end at the plains interface. This terrain makes the Front Range a challenging region to model. One of the more important flows created by this severe terrain are the highly-varying drainage flows found during stagnant, wintertime conditions. These flows can interact with larger-scale mountain and synoptic winds. One goal of the ASCOT 1991 program was to gain insight into multi-scale meteorological interaction by observing wintertime drainage conditions at the mountain-valley-plains interface. ASCOT data included surface and upper air measurements on approximately a 50km{sup 2} scale. Simultaneously, an SF{sub 6} tracer release study was being conducted around Rocky Flats, a nuclear materials production facility. Detailed surface concentration measurements were completed for the SF{sub 6} plume. This combination of meteorological and tracer concentration data provided a unique data set for comparisons of mesoscale and dispersion modeling results with observations and for evaluating our capability to predict pollutant transport. Our approach is to use the Regional Atmospheric Modeling System (RAMS) mesoscale model to simulate atmospheric conditions and the Lagrangian Particle Dispersion Model (LPDM) to model the dispersion of the SF{sub 6}.

  18. Drainage flows: A mountain-plains interface numerical case study

    SciTech Connect

    Poulos, G.S.; Bossert, J.E.

    1992-09-01

    In January/February, 1991 an intensive set of measurements was taken around Rocky Flats near Denver, CO, USA under the auspices of the Atmospheric Studies in Complex Terrain (ASCOT) program. This region of the country is known as the Front Range, and is characterized by a transition from the relatively flat terrain of the Great Plains to the highly varied terrain of the Rocky Mountains. The mountains are oriented north-south and rise from 1800m above mean sea level (MSL) to 3600m MSL at the Continental Divide. Numerous east-west oriented valleys begin in the mountains and end at the plains interface. This terrain makes the Front Range a challenging region to model. One of the more important flows created by this severe terrain are the highly-varying drainage flows found during stagnant, wintertime conditions. These flows can interact with larger-scale mountain and synoptic winds. One goal of the ASCOT 1991 program was to gain insight into multi-scale meteorological interaction by observing wintertime drainage conditions at the mountain-valley-plains interface. ASCOT data included surface and upper air measurements on approximately a 50km{sup 2} scale. Simultaneously, an SF{sub 6} tracer release study was being conducted around Rocky Flats, a nuclear materials production facility. Detailed surface concentration measurements were completed for the SF{sub 6} plume. This combination of meteorological and tracer concentration data provided a unique data set for comparisons of mesoscale and dispersion modeling results with observations and for evaluating our capability to predict pollutant transport. Our approach is to use the Regional Atmospheric Modeling System (RAMS) mesoscale model to simulate atmospheric conditions and the Lagrangian Particle Dispersion Model (LPDM) to model the dispersion of the SF{sub 6}.

  19. American Studies and the Technical Curriculum: Man and Technology.

    ERIC Educational Resources Information Center

    St. Germain, Amos

    An approach to teaching American studies at a Southern institute of engineering technology is described. The curriculum of this school is technically oriented to the professional engineer. Elective humanities courses must attract their own market and justify their places to both the students and the faculty. Two courses entitled "Man and…

  20. Management Studies Educational Knowledge: Technical, Elite or Political?

    ERIC Educational Resources Information Center

    Hordern, Jim

    2014-01-01

    This paper draws on the technical, elite and political interpretations of the purpose of management, to identify demands for particular forms of educational knowledge in the management studies curriculum. The varied character of this knowledge is discussed using Bernsteinian concepts of verticality, grammaticality, classification and framing, and…

  1. English Language Proficiency Study (ELPS), 1982 Microdata File. Technical Documentation.

    ERIC Educational Resources Information Center

    Bureau of the Census (DOC), Suitland, MD.

    This document consists of the printed technical documentation that accompanies the English Language Proficiency Study (ELPS) machine-readable data file when obtained from the Bureau of the Census. The ELPS was conducted by the United States Bureau of the Census for the Department of Education to provide materials with which the Department of…

  2. Western Wind and Solar Integration Study Phase 3: Technical Overview

    SciTech Connect

    2015-11-01

    Technical fact sheet outlining the key findings of Phase 3 of the Western Wind and Solar Integration Study (WWSIS-3). NREL and GE find that with good system planning, sound engineering practices, and commercially available technologies, the Western grid can maintain reliability and stability during the crucial first minute after grid disturbances with high penetrations of wind and solar power.

  3. New Training Technologies. Studies on Technical and Vocational Education 2.

    ERIC Educational Resources Information Center

    Herremans, Albert

    This book is the second in a series aiming to promote international exchange of ideas, experiences, and studies relating to technical and vocational education. Information provided is designed to help educators and trainers plan for an intelligent use of new training technologies (NTTs) to improve the access to basic and advanced lifelong learning…

  4. A Case Study on the Design of Learning Interfaces

    ERIC Educational Resources Information Center

    Perry, Gabriela Trindade; Schnaid, Fernando

    2012-01-01

    The design of educational software interfaces is a complex task, given its high domain dependency and multidisciplinary nature. It requires that teachers' knowledge and pedagogical beliefs be incorporated into the interface, posing a challenge to both teachers and designers, as they have to act as partners from the earliest phases of the process,…

  5. Studies of interfaces and vapors with Optical Second Harmonic Generation

    SciTech Connect

    Mullin, C. S.

    1993-12-01

    Optical Second Harmonic Generation (SHG) has been applied to the study of soap-like molecules adsorbed to the water-air interface. By calibrating the signal from a soluble monolayer with that of an insoluble homolog, absolute measurements of the surface density could be obtained and related to the bulk concentration and surface tension. We could then demonstrate that the soluble surfactant forms a single monolayer at the interface. Furthermore, it deviates significantly from the ideal case in that its activity coefficients are far from 1, yet those coefficients remain constant over a broad range of surface pressures. We present evidence of a first-order phase transition taking place during the adsorption of this soluble monolayer. We consider the effects of the non-ideal behavior and the phase transition on the microscopic model of adsorption, and formulate an alternative to the Langmuir picture of adsorption which is just as simple, yet it can more easily allow for non-ideal behavior. The second half of this thesis considers the problem of SHG in bulk metal vapors. The symmetry of the vapor forbids SHG, yet it has been observed. We consider several models whereby the symmetry of the vapor is broken by the presence of the laser and compare their predictions to new observations we have made using a few-picosecond laser pulse. The two-lobed output beam profile shows that it is the vapor-plus-beam combination whose symmetry is important. The dependence on vapor pressure demonstrates the coherent nature of the radiation, while the dependence on buffer gas pressure hints at a change of the symmetry in time. The time-dependence is measured directly with a preliminary pump-probe measurement. The magnitude and intensity dependence of the signal are also measured. All but one of the models are eliminated by this comparison.

  6. Technical Communications in Aeronautics: Results of an Exploratory Study. NASA Technical Memorandum 101534, Parts 1 and 2.

    ERIC Educational Resources Information Center

    Pinelli, Thomas E.; And Others

    An exploratory study investigated technical communications in aeronautics by surveying aeronautical engineers and scientists. The study had five specific objectives: to solicit the opinions of aeronautical engineers and scientists regarding the importance of technical communications to their profession; to determine their use and production of…

  7. A study of dilational rheological properties of polymers at interfaces.

    PubMed

    Cao, Xulong; Li, Yang; Jiang, Shengxiang; Sun, Huanquan; Cagna, Alain; Dou, Lixia

    2004-02-15

    Viscoelastic properties of two polymers, partially hydrolyzed polyacrylamide and partially hydrolyzed modified polyacrylamide, widely used in chemical flooding in the petroleum industry, were investigated at three interfaces, water-air, water-dodecane, and water-crude oil, by means of a dilational method provided by I.T. Concept, France, at 85 degrees C. Polymer solutions were prepared in brine with 10,000 mg/l sodium chloride and 2000 mg/l calcium chloride. It has been shown that the viscoelastic modulus increases with the increment of polymer concentration in the range of 0-1500 mg/l at the water-air interface. Each polymer shows different viscoelatic behavior at different interfaces. Generally speaking, values of the viscoelastic modulus (E), the real part (E'), and the imaginary part (E") at the crude oil-water interface for each polymer are lower than at the air-water or water-dodecane interface. The two polymers display different interfacial properties at the same interface. Polymer No. 2 gives more viscous interfaces than polymer No. 1. All the information obtained from this paper will be helpful in understanding the interfacial rheology of ultra-high-molecular-weight polymer solutions. PMID:14697692

  8. Ballistic Electron Emission Microscopy Studies of Ferromagnet - Semiconductor Interfaces

    NASA Astrophysics Data System (ADS)

    Mather, P. G.; Perrella, A. C.; Yurtsever, A.; Buhrman, R. A.

    2004-03-01

    Devices that employ spin as well as charge effects have been the subjects of extensive study recently. The magnetic tunneling transistor (1) is one important device that demonstrates an electrical means of injecting spin-polarized electrons into a semiconductor. A Schottky barrier lies at the heart of the device, and a high quality spatially homogenous and uniform barrier formed on GaAs is highly desirable. We have used ballistic electron emission microscopy (BEEM) to study CoFe, Fe and permalloy deposited on a GaAs substrate to give nanometer resolved evaluation of hot electron transport through the films and across the Schottky barrier. All films give a homogenous, uniform barrier as compared with evaporated Au/GaAs and Ag/GaAs interfaces. We will report on BEEM measurements of the hot electron transfer ratio across the Schottky barrier for the different ferromagnetic materials, and on the energy and spin-dependent hot electron attenuation lengths of the CoFe, Fe, and permalloy films. (1) Sebastiaan van Dijken, Xin Jiang, Stuart S. P. Parkin, APL, 80, 3364.

  9. Technical Communications in Aeronautics: Results of an Exploratory Study. An Analysis of Managers' and Nonmanagers' Responses. NASA Technical Memorandum 101625.

    ERIC Educational Resources Information Center

    Pinelli, Thomas E.; And Others

    Data collected from an exploratory study concerned with the technical communications practices of aerospace engineers and scientists were analyzed to test the primary assumption that aerospace managers and nonmanagers have different technical communications practices. Five secondary assumptions were established for the analysis: (1) that the…

  10. Experimental study of an isochorically heated heterogeneous interface. A progress report

    SciTech Connect

    Fernandez, Juan Carlos

    2015-08-20

    Outline of the presentation: Studying possible mix / interface motion between heterogeneous low/high Z interfaces driven by 2-fluid or kinetic plasma effects (Heated to few eV, Sharp (sub µm) interface); Isochoric heating to initialize interface done with Al quasimonoenergetic ion beams on Trident; Have measured isochoric heating in individual materials intended for compound targets; Fielded experiments on Trident to measure interface motion (Gold-diamond, tin-aluminium); Measured heated-sample temperature with streaked optical pyrometry (SOP) (UT Austin led (research contract), SOP tests → heating uniformity Vs thickness on Al foils. Results are being analyzed.

  11. High-energy photoemission studies of oxide interfaces

    NASA Astrophysics Data System (ADS)

    Claessen, Ralph

    2015-03-01

    The interfaces of complex oxide heterostructures can host novel quantum phases not existing in the bulk of the constituents, with the high-mobility 2D electron system (2DES) in LaAlO3/SrTiO3 (LAO/STO) representing a prominent example. Despite extensive research the origin of the 2DES and its unusual properties - including the supposed coexistence of superconductivity and ferromagnetism - are still a matter of intense debate. Photoelectron spectroscopy, recently extended into the soft (SX-ARPES) and hard (HAXPES) X-ray regime, is a powerful method to provide detailed insight into the electronic structure of these heterostructures and, in particular, of the buried interface. This includes the identification of the orbital character of the 2DES as well as the determination of vital band structure information, such as band alignment, band bending, and even k-resolved band dispersions and Fermi surface topology. Moreover, resonant photoemission at the Ti L-edge reveals the existence of two different species of Ti 3d states, localized and itinerant, which can be distinguished and identified by their different resonance behavior. The role of oxygen vacancies is studied by controlled in-situ oxidation, which allows us to vary the composition from fully stoichiometric to strongly O-deficient. By comparison to free STO surfaces we can thus demonstrate that the metallicity of the heteointerfaces is intrinsic, i . e . it persists even in the absence of O defects. I will discuss our photoemission results on LAO/STO heterostructures in both (100) and (111) orientation as well as on the related system γ-Al2O3/STO(100), which also hosts a 2DES with an even higher mobility. Work in collaboration with J. Mannhart (MPI-FKF, Stuttgart), N. Pryds (TU Denmark), G. Rijnders (U Twente), S. Suga (U Osaka), M. Giorgoi (BESSY, HZB), W. Drube (DESY Photon Science), V.N. Strocov (Swiss Light Source), J. Denlinger (Advanced Light Source, LBNL), and T.-L. Lee (Diamond Light Source). Support by

  12. Experimental Studies of Nanobubbles at Solid-Water Interfaces

    NASA Astrophysics Data System (ADS)

    Zhang, Xuehua

    2013-11-01

    When a hydrophobic substrate is in contact with water, gas bubbles thinner than 100 nm can form at the interface and stay for long time under ambient conditions. These nanobubbles have significant influence on a range of interfacial processes. For example, they give rise to hydrodynamic slip on the boundary, initiate the rupture of thin liquid films, facilitate the long-ranged interactions between hydrophobic surfaces, and enhance the attachment of a macroscopic bubble to the substrate. Experimentally, it is nontrivial to characterize such small fragile bubbles and unravel their fundamental physical properties. Based on our established procedure for the nanobubble formation, we have systematically studied the formation, stability and response of nanobubbles to external fields (e.g. sonication, pressure drop and temperature rise). By following the bubble morphology by atomic force microscopy, we show that the loss or gain of the nanobubble volume is achieved mainly by the change in the bubble height. The pinning on the three-phase boundary has significant implication on the properties of nanobubbles under various conditions. This talk will cover the effects of the substrate structures on the nanobubble formation, and the response of nanobubbles to the gas dissolution, the temperature increase, the extended gentle ultrasound or the substantial pressure drop in the environment. We acknowledge the support from Australian Research Council (FFT120100473).

  13. Ultrafast optical studies of surface reaction processes at semiconductor interfaces

    SciTech Connect

    Miller, R.J.D.

    1993-03-01

    Rectifying properties of semiconductor liquid junctions make them a simple system for converting and storing optical energy. However, interfacial electron or hole carrier transfer and competing non-radiative (energy loss) channels are not well understood at surfaces. This research has explored the use of three optical techniques, Surface Space Charge Electrooptic Sampling, Surface Restricted Transient Grating Spectroscopy, and Femtosecond Optical Kerr Spectroscopy (OKE) to obtain time evolution of the surface spatial distribution of photogenerated charge carriers, photocarrier population dynamics at semiconductor interfaces, and solvent modes responsible for charge localization and separation. These studies have shown that carriers arrive at GaAs(100) surfaces on the hundred femtosecond time scale. Improvements in time resolution, using surface grating spectroscopy, have shown interfacial hole transfer is occurring on the picosecond time scale. The OKE approach to solvent dynamics has determined the response of water to a field is multiexpontential with a major relaxation component of 100 femtoseconds. The observed interfacial hole transfer to Se[sup [minus]2] acceptors is occurring on this same time scale. This observation illustrates charge transfer processes can occur in the strong electronic coupling limit and can be competitive with carrier thermalization.

  14. Study of Composite Interface Fracture and Crack Growth Monitoring Using Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Bily, Mollie A.; Kwon, Young W.; Pollak, Randall D.

    2010-08-01

    Interface fracture of woven fabric composite layers was studied using Mode II fracture testing. Both carbon fiber and E-glass fiber composites were used with a vinyl ester resin. First, the single-step cured (i.e., co-cured) composite interface strength was compared to that of the two-step cured interface as used in the scarf joint technique. The results showed that the two-step cured interface was as strong as the co-cured interface. Carbon nanotubes were then applied to the composite interface using two-step curing, and then followed by Mode II fracture testing. The results indicated a significant improvement of the interface fracture toughness due to the dispersed carbon nanotube layer for both carbon fiber and E-glass fiber composites. The carbon nanotube layer was then evaluated as a means to monitor crack growth along the interface. Because carbon nanotubes have very high electrical conductivity, the electrical resistance was measured through the interface as a crack grew, thus disrupting the carbon nanotube network and increasing the resistance. The results showed a linear relationship between crack length and interface resistance for the carbon fiber composites, and allowed initial detection of failure in the E-glass fiber composites. This study demonstrated that the application of carbon nanotubes along a critical composite interface not only improves fracture properties but can also be used to detect and monitor interfacial damage.

  15. Discrete Element study of granular material - Bumpy wall interface behavior

    NASA Astrophysics Data System (ADS)

    El Cheikh, Khadija; Rémond, Sébastien; Pizette, Patrick; Vanhove, Yannick; Djelal, Chafika

    2016-09-01

    This paper presents a DEM study of a confined granular material sheared between two parallel bumpy walls. The granular material consists of packed dry spherical particles. The bumpiness is modeled by spheres of a given diameter glued on horizontal planes. Different bumpy surfaces are modeled by varying diameter or concentration of glued spheres. The material is sheared by moving the two bumpy walls at fixed velocity. During shear, the confining pressure applied on each bumpy wall is controlled. The effect of wall bumpiness on the effective friction coefficient and on the granular material behavior at the bumpy walls is reported for various shearing conditions. For given bumpiness and confining pressure that we have studied, it is found that the shear velocity does not affect the shear stress. However, the effective friction coefficient and the behavior of the granular material depend on the bumpiness. When the diameter of the glued spheres is larger than about the average grains diameter of the medium, the latter is uniformly sheared and the effective friction coefficient remains constant. For smaller diameters of the glued spheres, the effective friction coefficient increases with the diameter of glued spheres. The influence of glued spheres concentration is significant only for small glued spheres diameters, typically half of average particle diameter of the granular material. In this case, increasing the concentration of glued spheres leads to a decrease in effective friction coefficient and to shear localization at the interface. For different diameters and concentrations of glued spheres, we show that the effect of bumpiness on the effective friction coefficient can be characterized by the depth of interlocking.

  16. Positron annihilation lifetime study of interfaces in ternary polymer blends

    NASA Astrophysics Data System (ADS)

    Meghala, D.; Ramya, P.; Pasang, T.; Raj, J. M.; Ranganathaiah, C.; Williams, J. F.

    2013-06-01

    A new method based on positron lifetime spectroscopy is developed to characterize individual interfaces in ternary polymer blends and hence determine the composition dependent miscibility level. The method owes its origin to the Kirkwood-Risemann-Zimm (KRZ) model for the evaluation of the hydrodynamic interaction parameters (αij) which was used successfully for a binary blend with a single interface. The model was revised for the present work for ternary polymer blends to account for three interfaces. The efficacy of this method is shown for two ternary blends namely poly(styrene-co-acrylonitrile)/poly (ethylene-co-vinylacetate)/poly(vinyl chloride) (SAN/EVA/PVC) and polycaprolactone /poly(styrene-co-acrylonitrile)/poly(vinyl chloride) (PCL/SAN/PVC) at different compositions. An effective hydrodynamic interaction parameter, αeff, was introduced to predict the overall miscibility of ternary blends.

  17. Market assessment and technical feasibility study of PFBC ash use

    SciTech Connect

    Smith, V.E.; Bland, A.E.; Brown, T.H.; Georgiou, D.N.; Wheeldon, J.

    1994-10-01

    The overall objectives of this study are to determine the market potential and the technical feasibility of using PFBC ash in high volume ash use applications. The information will be of direct use to the utility industry in assessing the economics of PFBC power generation in light of ash disposal avoidance through ash marketing. In addition, the research is expected to result in the generation of generic data on the use of PFBC ash that could lead to novel processing options and procedures. The specific objectives of the proposed research and demonstration effort are: Define resent and future market potential of PFBC ash for a range of applications (Phase I); assess the technical feasibility of PFBC ash use in construction, civil engineering and agricultural applications (Phase II); and demonstrate the most promising of the market and ash use options in full-scale field demonstrations (Phase III).

  18. The Effects of Degraded Digital Instrumentation and Control Systems on Human-system Interfaces and Operator Performance: HFE Review Guidance and Technical Basis

    SciTech Connect

    O'Hara, J.M.; W. Gunther, G. Martinez-Guridi

    2010-02-26

    New and advanced reactors will use integrated digital instrumentation and control (I&C) systems to support operators in their monitoring and control functions. Even though digital systems are typically highly reliable, their potential for degradation or failure could significantly affect operator performance and, consequently, impact plant safety. The U.S. Nuclear Regulatory Commission (NRC) supported this research project to investigate the effects of degraded I&C systems on human performance and plant operations. The objective was to develop human factors engineering (HFE) review guidance addressing the detection and management of degraded digital I&C conditions by plant operators. We reviewed pertinent standards and guidelines, empirical studies, and plant operating experience. In addition, we conducted an evaluation of the potential effects of selected failure modes of the digital feedwater system on human-system interfaces (HSIs) and operator performance. The results indicated that I&C degradations are prevalent in plants employing digital systems and the overall effects on plant behavior can be significant, such as causing a reactor trip or causing equipment to operate unexpectedly. I&C degradations can impact the HSIs used by operators to monitor and control the plant. For example, sensor degradations can make displays difficult to interpret and can sometimes mislead operators by making it appear that a process disturbance has occurred. We used the information obtained as the technical basis upon which to develop HFE review guidance. The guidance addresses the treatment of degraded I&C conditions as part of the design process and the HSI features and functions that support operators to monitor I&C performance and manage I&C degradations when they occur. In addition, we identified topics for future research.

  19. Kinetic studies of the sucrose adsorption onto an alumina interface

    NASA Astrophysics Data System (ADS)

    Singh, Kaman; Mohan, Sudhanshu

    2004-01-01

    An account is given of an experimental kinetic study of adsorption of analar reagent sucrose (ARS) onto an alumina interface spectrometrically ( λmax=570 nm) at pH 8.0 and at room temperature. The adsorption isotherm is a typical Langmuirian isotherm (S-type) and adsorption parameters have been deduced according to the Langmuir's model. The adsorption coefficient evaluated from the Langmuir's equation was found to be 2.52×10 2 l mol -1. Adsorption mechanism has been interpreted on the basis of metal-saccharide interaction as found in organometallic compounds and interaction due to negatively charged ends on the disaccharide molecules and positively charge groups on the surface on alumina which depends on the pH value. The effects of variation in experimental conditions of the adsorption system have also been investigated. The adsorption exhibited a typical response to the pH effect and on going towards the PZC the net charge decreases and any reaction making dependence on charge and maximum adsorption (amount) was found near the isoelectric point of alumina (pH 9.0). The presence of ions like Cl -, SO 42- and PO 43- affect the adsorbed amount quantitatively and it seems that these anions compete with sucrose for the positively charged surface sites. The addition of similar concentration of cations was found to reduce the adsorbed amount. The temperature was found to have an inverse effect on adsorption. The additions of catonic and anionic detergents influence both the adsorbed amount and the adsorption rate. The thermodynamics of the titled adsorption model indicates the spontaneous and exothermic nature. The negative value of entropy is an indication of probability of favorable and complex nature of the adsorption.

  20. Study of lumineers' interfaces by means of optical coherence tomography

    NASA Astrophysics Data System (ADS)

    de Andrade Borges, Erica; Fernandes Cassimiro-Silva, Patrícia; Osório Fernandes, Luana; Leônidas Gomes, Anderson Stevens

    2015-06-01

    OCT has been used to evaluate dental materials, and is employed here to evaluate lumineers for the first time. Lumineers are used as esthetical indirect restoration, and after wearing and aging, several undesirable features such as gaps, bubbles and mismatch can appear in which would only be seen by invasive analysis. The OCT (spectral domain SD-OCT, 930nm central wavelength) was used to evaluate noninvasively the lumineer- cement-tooth interface. We analyzed 20 specimens of lumineers-teeth that were prepared in bovine teeth and randomly allocated in 4 experimental groups (n=5) with two different cementation techniques and two different types of cementing agent (RelyX U200 and RelyX Veneer, 3M ESPE, with the adhesive recommended by the manufacture). The lumineers were made of lithium disilicate and obtained using a vacuum injection technique. The analysis was performed by using 2D and 3D OCT images, obtained before and after cementing and the thermal cycling process to simulate thermal stress in a oral cavity. Initial measurements showed that the SD-OCT was able to see through the 500μm thick lumineer, as delivered by the fabricant, and internal stress was observed. Failures were found in the cementing process and also after ageing simulation by thermal cycling. The adhesive failures as bubbles, gaps and degradation of the cementation line are the natural precursors of other defects reported by several studies of clinical follow-up (detachments, fractures and cracks). Bubble dimensions ranging from 146 μm to 1427 μm were measured and the OCT was validated as an investigative and precise tool for evaluation of the lumineer-cement-tooth.

  1. Transport, Interfaces, and Modeling in Amorphous Silicon Based Solar Cells: Final Technical Report, 11 February 2002 - 30 September 2006

    SciTech Connect

    Schiff, E. A.

    2008-10-01

    Results for a-Si characteristics/modeling; photocarrier drift mobilities in a-Si;H, ..mu..c-Si:H, CIGS; hole-conducting polymers as p-layer for a-Si and c-Si; IR spectra of p/i and n/i interfaces in a-Si.

  2. Communication Platform Payload Definition (CPPD) study. Volume 2: Technical report

    NASA Technical Reports Server (NTRS)

    Hunter, E. M.; Driggers, T.; Jorasch, R.

    1986-01-01

    This is Volume 2 (Technical Report) of the Ford Aerospace & Communications Corporation Final Report for the Communication Platform Payload Definition (CPPD) Study program conducted for NASA Lewis Research Center under contract No. NAS3-24235. This report presents the results of the study effort leading to five potential platform payloads to service CONUS and WARC Region 2 traffic demand as projected to the year 2008. The report addresses establishing the data bases, developing service aggregation scenarios, selecting and developing 5 payload concepts, performing detailed definition of the 5 payloads, costing them, identifying critical technology, and finally comparing the payloads with each other and also with non-aggregated equivalent services.

  3. Technical Issues Map for the NHI System Interface and Support Systems Area: 2nd Quarter FY07

    SciTech Connect

    Steven R. Sherman

    2007-03-01

    This document provides a mapping of technical issues associated with development of the Next Generation Nuclear Plant (NGNP) intermediate heat transport loop and nuclear hydrogen plant support systems to the work that has been accomplished or is currently underway in the 2nd quarter of FY07.

  4. Student-Centered and Dynamic Interfaces that Enrich Technical Learning for Online Science Learners: A Review of the Literature

    ERIC Educational Resources Information Center

    Killian, Susan A.; Beck, Dennis E.; O'Bryan, Corliss A.; Jarvis, Nathan; Clausen, Edgar C.; Crandall, Philip G.

    2014-01-01

    Communicating complex scientific and technical information presents a challenge for food science educators. The most efficient learning occurs when all senses are engaged, one reason that many educators believe that scientific principles are best taught with hands-on laboratory experiences. Today there are many challenges to the continuation of…

  5. XPS Study of Oxide/GaAs and SiO2/Si Interfaces

    NASA Technical Reports Server (NTRS)

    Grunthaner, F. J.; Grunthaner, P. J.; Vasquez, R. P.; Lewis, B. F.; Maserjian, J.; Madhukar, A.

    1982-01-01

    Concepts developed in study of SiO2/Si interface applied to analysis of native oxide/GaAs interface. High-resolution X-ray photoelectron spectroscopy (XPS) has been combined with precise chemical-profiling technique and resolution-enhancement methods to study stoichiometry of transitional layer. Results are presented in report now available.

  6. Feasibility study for future implantable neural-silicon interface devices.

    PubMed

    Al-Armaghany, Allann; Yu, Bo; Mak, Terrence; Tong, Kin-Fai; Sun, Yihe

    2011-01-01

    The emerging neural-silicon interface devices bridge nerve systems with artificial systems and play a key role in neuro-prostheses and neuro-rehabilitation applications. Integrating neural signal collection, processing and transmission on a single device will make clinical applications more practical and feasible. This paper focuses on the wireless antenna part and real-time neural signal analysis part of implantable brain-machine interface (BMI) devices. We propose to use millimeter-wave for wireless connections between different areas of a brain. Various antenna, including microstrip patch, monopole antenna and substrate integrated waveguide antenna are considered for the intra-cortical proximity communication. A Hebbian eigenfilter based method is proposed for multi-channel neuronal spike sorting. Folding and parallel design techniques are employed to explore various structures and make a trade-off between area and power consumption. Field programmable logic arrays (FPGAs) are used to evaluate various structures. PMID:22254974

  7. TEM and XPS studies on CdS/CIGS interfaces

    NASA Astrophysics Data System (ADS)

    Han, Jun-feng; Liao, Cheng; Cha, Li-mei; Jiang, Tao; Xie, Hua-mu; Zhao, Kui; Besland, M.-P.

    2014-12-01

    Copper indium gallium selenide (CIGS) was deposited by metallic precursors sputtering and subsequently submitted to a selenization process. The upper CdS layers were deposited by chemical bath deposition (CBD) technique. The CdS/CIGS interfaces were investigated by Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). As checked by XPS analysis, the CIGS surface exhibited a hydroxide-terminated CdSe layer when treated with Cd Partial Electrolyte solution (Cd PE). Its thickness was roughly estimated to several nanometers. A 100 nm thick CdS layer was deposited onto CIGS surface. The TEM images revealed a clear and sharp interface between CdS and CIGS. XPS analysis showed a CIGS surface covered by a pinhole free and homogeneous CdS layer. XPS depth profile measurement of the CdS/CIGS interface did not evidence elemental inter-diffusion between the CIGS and CdS layers, in very good agreement with TEM observations.

  8. Interaction of monovalent ions with the water liquid-vapor interface - A molecular dynamics study

    NASA Technical Reports Server (NTRS)

    Wilson, Michael A.; Pohorille, Andrew

    1991-01-01

    Results of molecular dynamics calculations are presented for a series of ions at infinite dilution near the water liquid-vapor interface. The free energies of ion transfer from the bulk to the interface are discussed, as are the accompanying changes of water structure at the surface and ion mobilities as a function of their proximity to the interface. It is shown that simple dielectric models do not provide an accurate description of ions at the water surface. The results of the study should be useful in the development of better models incorporating the shape and molecular structure of the interface.

  9. First-principles study on oxidation of Ge and its interface electronic structures

    NASA Astrophysics Data System (ADS)

    Ono, Tomoya; Saito, Shoichiro; Iwase, Shigeru

    2016-08-01

    We review a series of first-principles studies on the defect generation mechanism and electronic structures of the Ge/GeO2 interface. Several experimental and theoretical studies proved that Si atoms at the Si/SiO2 interface are emitted to release interface stress. In contrast, total-energy calculation reveals that Ge atoms at the Ge/GeO2 interface are hardly emitted, resulting in the low trap density. Even if defects are generated, those at the Ge/GeO2 interface are found to behave differently from those at the Si/SiO2 interface. The states attributed to the dangling bonds at the Ge/GeO2 interface lie below the valence-band maximum of Ge, while those at the Si/SiO2 interface generate the defect state within the band gap of Si. First-principles electron-transport calculation elucidates that this characteristic behavior of the defect states is relevant to the difference in the leakage current through the Si/SiO2 and Ge/GeO2 interfaces.

  10. Advanced transportation system studies. Technical area 2: Heavy lift launch vehicle development. Volume 2; Technical Results

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Sections 10 to 13 of the Advanced Transportation System Studies final report are included in this volume. Section 10 contains a copy of an executive summary that was prepared by Lockheed Space Operations Company (LSOC) to document their support to the TA-2 contract during the first-year period of performance of the contract, May 1992 through May 1993. LSOC participated on the TA-2 contract as part of the concurrent engineering launch system definition team, and provided outstanding heavy lift launch vehicle (HLLV) ground operations requirements and concept assessments for Lockheed Missiles and Space Company (LMSC) through an intercompany work transfer as well as providing specific HLLV ground operations assessments at the direction of NASA KSC through KSC funding that was routed to the TA-2 contract. Section 11 contains a copy of a vehicle-independent, launch system health management requirements assessment. The purpose of the assessment was to define both health management requirements and the associated interfaces between a generic advanced transportation system launch vehicle and all related elements of the entire transportation system, including the ground segment. Section 12 presents the major TA-2 presentations provided to summarize the significant results and conclusions that were developed over the course of the contract. Finally, Section 13 presents the design and assessment report on the first lunar outpost heavy lift launch vehicle.

  11. Water at an electrochemical interface - a simulation study

    SciTech Connect

    Willard, Adam; Reed, Stewart; Madden, Paul; Chandler, David

    2008-08-22

    The results of molecular dynamics simulations of the properties of water in an aqueous ionic solution close to an interface with a model metallic electrode are described. In the simulations the electrode behaves as an ideally polarizable hydrophilic metal, supporting image charge interactions with charged species, and it is maintained at a constant electrical potential with respect to the solution so that the model is a textbook representation of an electrochemical interface through which no current is passing. We show how water is strongly attracted to and ordered at the electrode surface. This ordering is different to the structure that might be imagined from continuum models of electrode interfaces. Further, this ordering significantly affects the probability of ions reaching the surface. We describe the concomitant motion and configurations of the water and ions as functions of the electrode potential, and we analyze the length scales over which ionic atmospheres fluctuate. The statistics of these fluctuations depend upon surface structure and ionic strength. The fluctuations are large, sufficiently so that the mean ionic atmosphere is a poor descriptor of the aqueous environment near a metal surface. The importance of this finding for a description of electrochemical reactions is examined by calculating, directly from the simulation, Marcus free energy profiles for transfer of charge between the electrode and a redox species in the solution and comparing the results with the predictions of continuum theories. Significant departures from the electrochemical textbook descriptions of the phenomenon are found and their physical origins are characterized from the atomistic perspective of the simulations.

  12. Atomic-Scale Studies of Defect Interactions with Homo- and Heterophase Interfaces

    NASA Astrophysics Data System (ADS)

    Martínez, Enrique; Uberuaga, Blas P.; Beyerlein, Irene J.

    2016-04-01

    Interfaces are planar metastable defects with singular features capable of controlling diverse material properties, including mechanical response and the microstructure evolution in materials under irradiation. This ability of interfaces to dictate the material response resides inherently in their atomic structure, which controls the interactions of dislocations as well as point and defect clusters with the interface. We recently showed how dislocations nucleated from defect clusters interact with a heterophase interface in Cu-Nb layered composites. We also showed how the ability of the interface to absorb vacancy clusters depends on the atomic structure at the interface. Herein, we elaborate on the effect of the atomic structure on the ability of the interface to absorb dislocations as well as vacancy and self-interstitial defect clusters. We study a physical-vapor-deposited Kurdjumov-Sachs orientation in a Cu-Nb interface and an asymmetric Σ 11 grain boundary in pure Cu. On the one hand, the manner in which dislocations react with the interface depends on the misfit dislocation arrangement, which substantially differs between these two cases. On the other hand, vacancy and self-interstitial clusters are absorbed similarly upon interaction with both structures.

  13. Atomic-Scale Studies of Defect Interactions with Homo- and Heterophase Interfaces

    NASA Astrophysics Data System (ADS)

    Martínez, Enrique; Uberuaga, Blas P.; Beyerlein, Irene J.

    2016-06-01

    Interfaces are planar metastable defects with singular features capable of controlling diverse material properties, including mechanical response and the microstructure evolution in materials under irradiation. This ability of interfaces to dictate the material response resides inherently in their atomic structure, which controls the interactions of dislocations as well as point and defect clusters with the interface. We recently showed how dislocations nucleated from defect clusters interact with a heterophase interface in Cu-Nb layered composites. We also showed how the ability of the interface to absorb vacancy clusters depends on the atomic structure at the interface. Herein, we elaborate on the effect of the atomic structure on the ability of the interface to absorb dislocations as well as vacancy and self-interstitial defect clusters. We study a physical-vapor-deposited Kurdjumov-Sachs orientation in a Cu-Nb interface and an asymmetric Σ 11 grain boundary in pure Cu. On the one hand, the manner in which dislocations react with the interface depends on the misfit dislocation arrangement, which substantially differs between these two cases. On the other hand, vacancy and self-interstitial clusters are absorbed similarly upon interaction with both structures.

  14. Analysis of a display and control system man-machine interface concept. Volume 1: Final technical report

    NASA Technical Reports Server (NTRS)

    Karl, D. R.

    1972-01-01

    An evaluation was made of the feasibility of utilizing a simplified man machine interface concept to manage and control a complex space system involving multiple redundant computers that control multiple redundant subsystems. The concept involves the use of a CRT for display and a simple keyboard for control, with a tree-type control logic for accessing and controlling mission, systems, and subsystem elements. The concept was evaluated in terms of the Phase B space shuttle orbiter, to utilize the wide scope of data management and subsystem control inherent in the central data management subsystem provided by the Phase B design philosophy. Results of these investigations are reported in four volumes.

  15. A Theoretical Study of Remobilizing Surfactant Retarded Fluid Particle Interfaces

    NASA Technical Reports Server (NTRS)

    Wang, Yanping; Papageorgiou, Dimitri; Maldarelli, Charles

    1996-01-01

    Microgravity processes must rely on mechanisms other than bouyancy to move bubbles or droplets from one region to another in a continuous liquid phase. One suggested method is thermocapillary migration in which a temperature gradient is applied to the continuous phase. When a fluid particle contacts this gradient, one pole of the particle becomes warmer than the opposing pole. The interfacial tension between the drop or bubble phase and the continuous phase usually decreases with temperature. Thus the cooler pole is of higher interfacial tension than the warmer pole, and the interface is tugged in the direction of the cooler end. This thermocapillary or thermally induced Marangoni surface stress causes a fluid streaming in the continuous phase from which develops a viscous shear traction and pressure gradient which together propel the particle in the direction of the warmer fluid. In this paper, we provide a theoretical basis for remobilizing surfactant retarded fluid particle interfaces in an effort to make viable the use of thermocapillary migrations for the management of bubbles and drops in microgravity,

  16. Neutral buoyancy methodology for studying satellite servicing EVA crewmember interfaces

    NASA Technical Reports Server (NTRS)

    Barnby, Mary E.; Griffin, Thomas J.; Lewis, Ruthan

    1989-01-01

    Current economic constraints indicate the need for incorporating the satellite servicing philosophy of commonality within the design of spacecraft subsytems. This philosophy is essential for conserving resources including hardware/software development and implementation costs, on-orbit and ground-based manpower, crew training/testing time, and documentation. In addition, spacecraft subsystem commonality may be coupled with standardization of operation procedures, and test and verification techniques for spacecraft design. Several spacecraft have adopted this practice, including Hubble Space Telescope, Space Station Freedom, and the Explorer Platform. As these and other programs continue and if effective crew interfaces and procedures are clearly and consistently defined, crew retraining for similar spacecraft subsystems will lessen, and procurement efforts will diminish. A relatively high fidelity zero-gravity simulation using water immersion is available to establish crew interfaces economically. The flexibility and utility of this space simulation medium for planning and assisting on-orbit operations was exemplified by astronaut evaluations of potential EVA electrical connectors. The testing was conducted at a NASA underwater neutral buoyancy training facility.

  17. Comparison of the Booster Interface Temperature in Stainless Steel (SS) V-Channel versus the Aluminum (Al) Y-Channel Primer Chamber Assemblies (PCAs). Volume 1; Technical Assessment Report

    NASA Technical Reports Server (NTRS)

    Garcia, Roberto; Saulsberry, Regor L.

    2011-01-01

    NASA's Technical Fellow for Propulsion, requested a technical assessment of the performance improvement achieved by the introduction of the stainless steel (SS) V-channel compared to the aluminum (Al) Y-channel Primer Chamber Assembly (PCA) design. The SS V-channel PCA was developed for NASA's Mars Science Laboratory (MSL) Project. The principle focus of the assessment was to measure the transient temperature at the booster interface with both designs. This document contains the findings of the assessment.

  18. Spin labelled polymers for composite interface studies: Synthesis and characterization

    SciTech Connect

    Snow, A.W.; Pace, M.D.

    1993-12-31

    For the purpose of investigating the epoxy resin composite interface, a series of spin labelled epoxy polymers and model compounds were synthesized and characterized. Linear epoxy polymers were prepared by reacting systematically varying quantities of 4-amino-2,2,6,6-tetramethylpiperid-1-yloxy and cyclohexyl amine with an equivalence bisphenol A diglycidyl ether. The adducts of phenylgylcidyl ether and 4-cumylphenylgylcidyl ether with 4-amino-2,2,6,6-tetramethylpiperid-1-yloxy were synthesized as model compounds. Characterization determined that the 125{degrees}C polymerization temperature did not cause significant decomposition of the nitroxyl free radical, magnetic dilution of the spin label in the epoxy polymer to 3% of the amine repeat units is sufficient for observation of unobscured nitroxyl hyperfine structure in the ESR spectrum of the labelled epoxy polymer in the solid state, and a polymer glass transition temperature of 66{degrees}C as not affected by variation in the amine composition.

  19. Structural and phonon transmission study of Ge-Au-Ge eutectically bonded interfaces

    SciTech Connect

    Knowlton, W.B. |

    1995-07-01

    This thesis presents a structural analysis and phonon transparency investigation of the Ge-Au-Ge eutectic bond interface. Interface development was intended to maximize the interfacial ballistic phonon transparency to enhance the detection of the dark matter candidate WIMPs. The process which was developed provides an interface which produces minimal stress, low amounts of impurities, and insures Ge lattice continuity through the interface. For initial Au thicknesses of greater than 1,000 {angstrom} Au per substrate side, eutectic epitaxial growth resulted in a Au dendritic structure with 95% cross sectional and 90% planar Au interfacial area coverages. In sections in which Ge bridged the interface, lattice continuity across the interface was apparent. Epitaxial solidification of the eutectic interface with initial Au thicknesses < 500 A per substrate side produced Au agglomerations thereby reducing the Au planar interfacial area coverage to as little as 30%. The mechanism for Au coalescence was attributed to lateral diffusion of Ge and Au in the liquid phase during solidification. Phonon transmission studies were performed on eutectic interfaces with initial Au thicknesses of 1,000 {angstrom}, 500 {angstrom}, and 300 {angstrom} per substrate side. Phonon imaging of eutectically bonded samples with initial Au thicknesses of 300 {angstrom}/side revealed reproducible interfacial percent phonon transmissions from 60% to 70%. Line scan phonon imaging verified the results. Phonon propagation TOF spectra distinctly showed the predominant phonon propagation mode was ballistic. This was substantiated by phonon focusing effects apparent in the phonon imaging data. The degree of interface transparency to phonons and resulting phonon propagation modes correlate with the structure of the interface following eutectic solidification. Structural studies of samples with initial Au thickness of 1,000 {angstrom}/side appear to correspond with the phonon transmission study.

  20. Numerical and experimental study of the nonlinear interaction between a shear wave and a frictional interface.

    PubMed

    Blanloeuil, Philippe; Croxford, Anthony J; Meziane, Anissa

    2014-04-01

    The nonlinear interaction of shear waves with a frictional interface are presented and modeled using simple Coulomb friction. Analytical and finite difference implementations are proposed with both in agreement and showing a unique trend in terms of the generated nonlinearity. A dimensionless parameter ξ is proposed to uniquely quantify the nonlinearity produced. The trends produced in the numerical study are then validated with good agreement experimentally. This is carried out loading an interface between two steel blocks and exciting this interface with different amplitude normal incidence shear waves. The experimental results are in good agreement with the numerical results, suggesting the simple friction model does a reasonable job of capturing the fundamental physics. The resulting approach offers a potential way to characterize a contacting interface; however, the difficulty in activating that interface may ultimately limit its applicability. PMID:25234971

  1. Exploring the Capability of Evaluating Technical Solutions: A Collaborative Study into the Primary Technology Classroom

    ERIC Educational Resources Information Center

    Björkholm, Eva

    2014-01-01

    Within the field of technology education, evaluating technical solutions is considered as an important topic. Research indicates that pupils have difficulties in evaluating technical solutions in terms of fitness for purpose, i.e. how effective a technical solution supports its intended function. By using the learning study, which is an iterative…

  2. North American Natural Gas Markets: Selected technical studies

    SciTech Connect

    Huntington, H.G.; Schuler, G.E.

    1989-04-01

    The Energy Modeling Forum (EMF) was established in 1976 at Stanford University to provide a structural framework within which energy experts, analysts, and policymakers could meet to improve their understanding of critical energy problems. The ninth EMF study, North American Natural Gas Markets, was conducted by a working group comprised of leading natural gas analysts and decision-makers from government, private companies, universities, and research and consulting organizations. The EMF 9 working group met five times from October 1986 through June 1988 to discuss key issues and analyze natural gas markets. This third volume includes technical papers that support many of the conclusions discussed in the EMF 9 summary report (Volume 1) and full working group report (Volume 2). These papers discuss the results from the individual models as well as some nonmodeling analysis related to US natural gas imports and industrial natural gas demand. Individual papers have been processed separately for inclusion in the Energy Science and Technology Database.

  3. North American Natural Gas Markets: Selected technical studies. Volume 3

    SciTech Connect

    Huntington, H.G.; Schuler, G.E.

    1989-04-01

    The Energy Modeling Forum (EMF) was established in 1976 at Stanford University to provide a structural framework within which energy experts, analysts, and policymakers could meet to improve their understanding of critical energy problems. The ninth EMF study, North American Natural Gas Markets, was conducted by a working group comprised of leading natural gas analysts and decision-makers from government, private companies, universities, and research and consulting organizations. The EMF 9 working group met five times from October 1986 through June 1988 to discuss key issues and analyze natural gas markets. This third volume includes technical papers that support many of the conclusions discussed in the EMF 9 summary report (Volume 1) and full working group report (Volume 2). These papers discuss the results from the individual models as well as some nonmodeling analysis related to US natural gas imports and industrial natural gas demand. Individual papers have been processed separately for inclusion in the Energy Science and Technology Database.

  4. Thermal boundary conductance enhancement using experimentally achievable nanostructured interfaces - analytical study combined with molecular dynamics simulation.

    PubMed

    Lee, Eungkyu; Zhang, Teng; Hu, Ming; Luo, Tengfei

    2016-06-22

    Interfacial thermal resistance presents great challenges to the thermal management of modern electronics. In this work, we perform an analytical study to enhance the thermal boundary conductance (TBC) of nanostructured interfaces with square-shape pillar arrays, extendable to the characteristic lengths that can be fabricated in practice. As a representative system, we investigate a SiC substrate with the square-shape pillar array combined with epitaxial GaN as the nanostructured interface. By applying a first-order ray tracing method and molecular dynamics simulations to analyze phonon incidence and transmission at the nanostructured interface, we systematically study the impact of the characteristic dimensions of the pillar array on the TBC. Based on the multi-scale analysis we provide a general guideline to optimize the nanostructured interfaces to achieve higher TBC, demonstrating that the optimized TBC value of the nanostructured SiC/GaN interfaces can be 42% higher than that of the planar SiC/GaN interfaces without nanostructures. The model used and results obtained in this study will guide the further experimental realization of nanostructured interfaces for better thermal management in microelectronics. PMID:27275647

  5. Descriptive analysis of context evaluation instrument for technical oral presentation skills evaluation: A case study in English technical communication course

    NASA Astrophysics Data System (ADS)

    Mohamed, Abdullah-Adnan; Asmawi, Adelina; Hamid, Mohd Rashid Ab; Mustafa, Zainol bin

    2015-02-01

    This paper reports a pilot study of Context Evaluation using a self-developed questionnaire distributed among engineering undergraduates at a university under study. The study aims to validate the self-developed questionnaires used in the Context evaluation, a component in the CIPP Model. The Context evaluation assesses background information for needs, assets, problems and opportunities relevant to beneficiaries of the study in a defined environment. Through the questionnaire, background information for the assessment of needs, assets and problems related to the engineering undergraduates' perceptions on the teaching and learning of technical oral presentation skills was collected and analysed. The questionnaire was developed using 5-points Likert scale to measure the constructs under study. They were distributed to 100 respondents with 79 returned. The respondents consisted of engineering undergraduates studied at various faculties at one technical university in Malaysia. The descriptive analysis of data for each item which makes up the construct for Context evaluation is found to be high. This implied that engineering undergraduates showed high interest in teaching and learning of technical oral presentation skills, thus their needs are met. Also, they agreed that assets and facilities are conducive to their learning. In conclusion, the context evaluation involving needs and assets factors are both considerably important; their needs are met and the assets and facilities do support their technical oral presentation skills learning experience.

  6. Florida Study of Career and Technical Education. Final Report

    ERIC Educational Resources Information Center

    Jacobson, Louis; Mokher, Christine

    2014-01-01

    A key goal of the "Carl D. Perkins Career and Technical Education Act of 2006" ("Perkins IV") is to ensure career and technical education (CTE) programs are widely available for preparing high school and college students for "high skill, high wage, or high demand occupations in current or emerging professions"…

  7. Case Study: Sussex Technical High School, Georgetown, Delaware.

    ERIC Educational Resources Information Center

    Southern Regional Education Board, Atlanta, GA.

    A vocational-technical center in Delaware, launched a massive restructuring effort in 1988. Educators used frameworks provided by the National Center for Research in Vocational Education and Southern Regional Educational Board and visited High Schools That Work sites. In 1991, Sussex Technical High School opened its doors as a newly designed…

  8. Technical Services Cost Studies in ARL Libraries. SPEC Kit 125.

    ERIC Educational Resources Information Center

    Hoerman, Heidi Lee

    Based on a survey of Association of Research Libraries (ARL) member libraries in February 1986, this kit is designed to illustrate a wide range of alternative approaches to analyzing the costs of technical services. The kit consists of the following unedited primary-source documents: (1) SPEC Technical Services Costs Survey (Three-Year Update)…

  9. Elemental and structural studies at the bone-cartilage interface

    NASA Astrophysics Data System (ADS)

    Kaabar, W.; Daar, E.; Bunk, O.; Farquharson, M. J.; Laklouk, A.; Bailey, M.; Jeynes, C.; Gundogdu, O.; Bradley, D. A.

    2011-10-01

    Micro-Proton Induced X-ray Emission (μ-PIXE) and Proton Induced Gamma-ray Emission (PIGE) techniques were employed in the investigation of trace and essential elements distribution in normal and diseased human femoral head sections affected by osteoarthritis (OA). PIGE was exploited in the determination of elements of low atomic number z<15 such as Na and F whereas elements with z>15 viz Ca, Z, P and S were determined by PIXE. Accumulations of key elements in the bone and cartilage sections were observed, significant S and Na concentrations being found in the cartilage region particularly in normal tissues. Zn showed enhanced concentrations at the bone-cartilage interface. At a synchrotron facility, small angle X-ray scattering (SAXS) was utilized on a decalcified human femoral head section affected by OA, direct measurements being made of spatial alterations of collagen fibres. The SAXS results showed a slight decrease in the axial periodicity between normal collagen type I and that in diseased tissue in various sites, in contrast with the findings of others.

  10. Adsorption of Bovine Serum Albumin (BSA) at the Oil/Water Interface: A Neutron Reflection Study.

    PubMed

    Campana, M; Hosking, S L; Petkov, J T; Tucker, I M; Webster, J R P; Zarbakhsh, A; Lu, J R

    2015-05-26

    The structure of the adsorbed protein layer at the oil/water interface is essential to the understanding of the role of proteins in emulsion stabilization, and it is important to glean the mechanistic events of protein adsorption at such buried interfaces. This article reports on a novel experimental methodology for probing protein adsorption at the buried oil/water interface. Neutron reflectivity was used with a carefully selected set of isotopic contrasts to study the adsorption of bovine serum albumin (BSA) at the hexadecane/water interface, and the results were compared to those for the air/water interface. The adsorption isotherm was determined at the isoelectric point, and the results showed that a higher degree of adsorption could be achieved at the more hydrophobic interface. The adsorbed BSA molecules formed a monolayer on the aqueous side of the interface. The molecules in this layer were partially denatured by the presence of oil, and once released from the spatial constraint by the globular framework they were free to establish more favorable interactions with the hydrophobic medium. Thus, a loose layer extending toward the oil phase was clearly observed, resulting in an overall broader interface. By analogy to the air/water interface, as the concentration of BSA increased to 1.0 mg mL(-1) a secondary layer extending toward the aqueous phase was observed, possibly resulting from the steric repulsion upon the saturation of the primary monolayer. Results clearly indicate a more compact arrangement of molecules at the oil/water interface: this must be caused by the loss of the globular structure as a consequence of the denaturing action of the hexadecane. PMID:25875917

  11. OEXP exploration studies technical report. Volume 3: Special reports, studies, and indepth systems assessments

    NASA Technical Reports Server (NTRS)

    Roberts, Barney B.; Bland, Dan

    1988-01-01

    The Office of Exploration (OEXP) at NASA has been tasked with defining and recommending alternatives for an early 1990's national decision on a focused program of manned exploration of the Solar System. The Mission analysis and System Engineering (MASE) group, which is managed by the Exploration Studies Office at the Johnson Space Center, is responsible for coordinating the technical studies necessary for accomplishing such a task. This technical report, produced by the MASE, describes the process used to conduct exploration studies and discusses the mission developed in a case study approach. The four case studies developed in FY88 include: (1) a manned expedition to PHOBOS; (2) a manned expedition to MARS; (3) a lunar surface observatory; and a lunar outpost to early Mars evolution. The final outcome of this effort is a set of programmatic and technical conclusions and recommendations for the following year's work.

  12. A multi-imaging approach to study the root–soil interface

    PubMed Central

    Rudolph-Mohr, Nicole; Vontobel, Peter; Oswald, Sascha E.

    2014-01-01

    Background and Aims Dynamic processes occurring at the soil–root interface crucially influence soil physical, chemical and biological properties at a local scale around the roots, and are technically challenging to capture in situ. This study presents a novel multi-imaging approach combining fluorescence and neutron radiography that is able to simultaneously monitor root growth, water content distribution, root respiration and root exudation. Methods Germinated seeds of white lupins (Lupinus albus) were planted in boron-free glass rhizotrons. After 11 d, the rhizotrons were wetted from the bottom and time series of fluorescence and neutron images were taken during the subsequent day and night cycles for 13 d. The following day (i.e. 25 d after planting) the rhizotrons were again wetted from the bottom and the measurements were repeated. Fluorescence sensor foils were attached to the inner sides of the glass and measurements of oxygen and pH were made on the basis of fluorescence intensity. The experimental set-up allowed for simultaneous fluorescence imaging and neutron radiography. Key Results The interrelated patterns of root growth and distribution in the soil, root respiration, exudation and water uptake could all be studied non-destructively and at high temporal and spatial resolution. The older parts of the root system with greater root-length density were associated with fast decreases of water content and rapid changes in oxygen concentration. pH values around the roots located in areas with low soil water content were significantly lower than the rest of the root system. Conclusions The results suggest that the combined imaging set-up developed here, incorporating fluorescence intensity measurements, is able to map important biogeochemical parameters in the soil around living plants with a spatial resolution that is sufficiently high enough to relate the patterns observed to the root system. PMID:25344936

  13. Hybrid density functional study of oligothiophene/ZnO interface for photovoltaics

    SciTech Connect

    Sai, Na; Leung, Kevin; Chelikowsky, James R.

    2011-03-21

    Organic-inorganic donor-acceptor interfaces are gaining growing attention in organic photovoltaic applications as each component of the interface offers unique attributes. Here we use hybrid density functional theory to examine the electronic structure of sexithiophene/ZnO interfaces. We find that interfacial molecular orientations strongly influence the adsorption energy, the energy level alignment, and the open-circuit voltage. We attribute the orientation dependence to the varied strength of electronic coupling between the molecule and the substrate. Our study suggests that photovoltaic performance can be optimized by controlling the interfacial design of molecular orientations.

  14. A Guide for Evaluation of Technical and Vocational Education Curricula. Studies on Technical and Vocational Education 3.

    ERIC Educational Resources Information Center

    Kenneke, Larry

    This book is the third in a series aiming to promote international exchange of ideas, experiences, and studies relating to technical and vocational education. Intended to assist educators in the evaluation of vocational education curricula, the guide is designed for both experienced evaluators and novices. Section I describes the purpose,…

  15. Computational Study of ions binding to the liquid interface of water

    SciTech Connect

    Dang, Liem X. )

    2002-08-12

    We have performed extensive classical molecular dynamics simulations to examine the molecular transport mechanisms of the I-, Br-, Cl- and Na+ ions across the liquid/vapor interface of water. The potentials of mean force were calculated using the constrained mean force approach and polarizable potential models were used to describe the interactions among the species. The simulated potentials of mean force were found to be different, depending on the type of anion. The larger I- and Br- anions bind more strongly to the liquid/vapor interface of water than did the smaller Cl-ion. It is important to note here that most of the gas phase and solution phase properties of the Br- anion are quite similar to that of the Cl- ion. At the interface, however, the interactions of the Br- and Cl- anions with the water interface appeared to be significantly different. We found that the anions approach the interface more closely do than cations. We have also studied the transport mechanism of an I- across the water/dichloromethane interface. The computed potential of mean force showed no well-defined minimum as in the liquid/vapor case, but a stabilization free energy of about?1 kcal/mol near the interface with respect to the bulk liquid was observed. The I- anion carried a water molecule with it as it crossed the interface. This result is in agreement with a recent experimental study on a similar system. Our work differs from earlier contributions in that our potential models have taken many-body effects into account, and in some cases, these effects cannot be neglected. To the best of our knowledge, this work significantly advances our understanding of molecular processes at the liquid interfaces.

  16. Computer Simulation study of polyhedral nanoparticle self-assembly at interfaces

    NASA Astrophysics Data System (ADS)

    Thapar, Vikram; Gupta, Unmukt; Escobedo, Fernando

    The self-assembly of polyhedral particles confined to a fluid-fluid interface is studied using Monte Carlo simulations. Several polyhedral shapes are studied, which are selected from a family of truncated cubes which include cubes, cuboctahedra, and octahedra. First we studied the case of hard particles pinned to the interface by restricting their movement in the direction perpendicular to it while allowing their free rotations. Our results suggest that the known solid phases and mesophases of these shapes in the 3D bulk are ``translated'' into variants in 2D space. These insights on 2D entropic self-assembly of polyhedral particles is a first step toward understanding the self-assembly of particles at fluid-fluid interfaces, which is driven by a complex interplay of entropic and enthalpic forces. As a second step we hence studied the particle-surface and particle-particle interactions associated with a fluid-fluid interface using both continuum and polybead models to assess the role of enthalpic interactions in determining the particle orientation behavior with respect to interface. We find that the thickness of the interface can introduce non-trivial effects on the preferential particle orientations.

  17. Office of Exploration: Exploration studies technical report. Volume 2: Studies approach and results

    NASA Technical Reports Server (NTRS)

    Roberts, Barney B.; Bland, Dan

    1988-01-01

    The NASA Office of Exploration has been tasked with defining and recommending alternatives for an early 1990's national decision on a focused program of human exploration of the solar system. The Mission Analysis and System Engineering (MASE) group, which is managed by the Exploration Studies Office at the Johnson Space Center, is responsible for coordinating the technical studies necessary for accomplishing such a task. This technical report describes the process that has been developed in a case study approach. The four case studies that were developed in FY88 include: (1) human expedition to Phobos; (2) human expeditions to Mars; (3) lunar observatory; and (4) lunar outpost to early Mars evolution. The final outcome of this effort is a set of programmatic and technical conclusions and recommendations for the following year's work. Volume 2 describes the case study process, the technical results of each of the case studies, and opportunities for additional study. Included in the discussion of each case study is a description of the mission key features and profile. Mission definition and manifesting are detailed, followed by a description of the mission architecture and infrastructure. Systems concepts for the required orbital nodes, transportation systems, and planetary surface systems are discussed. Prerequisite implementation plans resulting from the synthesized case studies are described and in-depth assessments are presented.

  18. Crew time utilisation and Habitat interface investigations for future planetary habitat definition studies: field tests at MDRS

    NASA Astrophysics Data System (ADS)

    Pletser, Vladimir

    To prepare future Lunar and Martian planetary exploration definition studies, the European Space Agency (ESA) has interests in gathering data on human aspects during long term space and planetary exploration missions, namely limited resources, limited social interactions, long term living and working in confined and isolated areas. To assess their impact on long term space missions and to attempt a general quantification, the environmental and technical condi-tions to which astronauts may be confronted need to be reproduced as closely as possible. Used since 2001 to conduct various types of simulation campaigns of planetary exploration missions, The Mars Society's `Mars Desert Research Station' (MDRS) in the Desert of Utah is one of the analogue facilities suited for this kind of human aspect investigations. In this frame, the ESA's Directorate of Human Space Flight was associated to the EuroGeoMars campaign conducted in February 2009 by the MDRS Crews 76 and 77. The EuroGeoMars campaign lasted five weeks and encompassed two groups of experiments, on human crew related aspects and field experiments in geology, biology and astronomy/astrophysics. The human crew related aspects covered evaluations of (a) the different functions and interfaces of a planetary habitat, (b) the crew time organization, (c) man-machine interfaces of science and technical equipment. The paper recalls the objectives of the human crew related experiments of the EuroGeoMars cam-paign and presents the results of these field investigations. Some recommendations and lessons learnt are presented and used as first inputs for future planetary habitat definition studies.

  19. Studies of the Si/SiO2 interface using synchrotron radiation

    NASA Technical Reports Server (NTRS)

    Hecht, M. H.; Grunthaner, F. J.

    1985-01-01

    Synchrotron radiation photoemission spectroscopy (SRPS) in the 1-4 KeV photon energy range is a useful tool for interface characterization. Results are presented of a series of studies of the near-interface region of Si/SiO2 which confirm that a bond strain gradient exists in the oxide as a result of lattice mismatch. These experiments include measurement of photoemission lineshape changes as a function of photon energy, corresponding changes in the electron escape depth near the interface, and surface extended X-ray absorption fine structure (SEXAFS) measurements directly indicating the shortening of the Si-Si second nearest neighbor distance in the near-interface region of the oxide.

  20. Advanced EVA system design requirements study: EVAS/space station system interface requirements

    NASA Technical Reports Server (NTRS)

    Woods, T. G.

    1985-01-01

    The definition of the Extravehicular Activity (EVA) systems interface requirements and accomodations for effective integration of a production EVA capability into the space station are contained. A description of the EVA systems for which the space station must provide the various interfaces and accomodations are provided. The discussion and analyses of the various space station areas in which the EVA interfaces are required and/or from which implications for EVA system design requirements are derived, are included. The rationale is provided for all EVAS mechanical, fluid, electrical, communications, and data system interfaces as well as exterior and interior requirements necessary to facilitate EVA operations. Results of the studies supporting these discussions are presented in the appendix.

  1. Additive Manufacturing in Production: A Study Case Applying Technical Requirements

    NASA Astrophysics Data System (ADS)

    Ituarte, Iñigo Flores; Coatanea, Eric; Salmi, Mika; Tuomi, Jukka; Partanen, Jouni

    Additive manufacturing (AM) is expanding the manufacturing capabilities. However, quality of AM produced parts is dependent on a number of machine, geometry and process parameters. The variability of these parameters affects the manufacturing drastically and therefore standardized processes and harmonized methodologies need to be developed to characterize the technology for end use applications and enable the technology for manufacturing. This research proposes a composite methodology integrating Taguchi Design of Experiments, multi-objective optimization and statistical process control, to optimize the manufacturing process and fulfil multiple requirements imposed to an arbitrary geometry. The proposed methodology aims to characterize AM technology depending upon manufacturing process variables as well as to perform a comparative assessment of three AM technologies (Selective Laser Sintering, Laser Stereolithography and Polyjet). Results indicate that only one machine, laser-based Stereolithography, was feasible to fulfil simultaneously macro and micro level geometrical requirements but mechanical properties were not at required level. Future research will study a single AM system at the time to characterize AM machine technical capabilities and stimulate pre-normative initiatives of the technology for end use applications.

  2. In-situ Studies of Structures and Processes at Model Battery Electrode/Electrolyte Interfaces

    NASA Astrophysics Data System (ADS)

    Fenter, Paul

    2015-03-01

    The ability to understand and control materials properties within electrochemical energy storage systems is a significant scientific and technical challenge. This is due, at least in part, to the extreme conditions present within these systems, and the significant structural and chemical changes that take place as lithium ions are incorporated in the active electrode material. In particular, the behavior of interfaces in such systems is poorly understood, notably the solid-liquid interface that separates the electrode and the liquid electrolyte. I will review our recent work in which we seek to isolate and understand the role of interfacial reactivity in these systems through in-situ, real-time, observations of electrochemically driven lithiation/delithation reactions. This is achieved by observing well-defined model electrode-electrolyte interfaces using X-ray reflectivity. These results reveal novel understandings of interfacial reactivity in conversion reactions (e.g., Si, SixCr, Ge, NiO) that can be used to control the complex reaction lithiation pathway through the use of thin-film and multilayer electrode structures. This work was supported by the Center for Electrochemical Energy Science, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, in collaboration with T. Fister, A. Gewirth, M.J. Bedzyk and others.

  3. A study of interface crack branching in dissimilar anisotropic bimaterial composites including thermal effects

    NASA Astrophysics Data System (ADS)

    Li, Renfu

    The interface crack branching phenomena, including thermal effects, has been investigated by using complex variable method and Stroh's dislocation theory, extended to thermo-elasticity in matrix notation. As one of the most catastrophic failure modes in structures like laminated and sandwich composites in aerospace and marine construction, thin film in electronic packaging, rotators in high speed engine of aircraft and reactor in nuclear power station, the study of interface crack branching has become a topic not only having theoretical importance, but also having practical significance. A unified approach is presented to address the thermoelastic interface crack problems in dissimilar anisotropic bimaterial composites, and a compact closed form solution is formulated by analytical continuation principle of complex analysis. Employing the contour integral method, an explicit solution to the interaction between the dislocations and the interface crack is obtained. By modeling the branched portion as a continuous distribution of the dislocations, the thermoelastic interface crack branching problem is then converted to a set of semi-coupled singular integral equations and solved by Gauss-Jacobi integration schemes. The influence of material property mismatches between the two constituents and the thermal loading effects on the interface crack branching are demonstrated by extensive numerical simulation. Some useful criteria for predicting the interface crack branching growth and guidance for optimal composites design are suggested. Further, a contact model to eliminate the overlapping between the two surfaces of an interface crack is also proposed and some new parameters which could influence the interpenetrating phenomena are also discovered. The technique to extend the current method to three dimensional problems is also outlined. Furthermore, the C++ source code has been implemented to manipulate the complicated complex operations for numerically solving the

  4. The composing process of technical writers: A preliminary study

    NASA Technical Reports Server (NTRS)

    Mair, D.; Roundy, N.

    1981-01-01

    The assumption that technical writers compose as do other writers is tested. The literature on the composing process, not limited to the pure or applied sciences, was reviewed, yielding three areas of general agreement. The composing process (1) consists of several stages, (2) is reflexive, and (3) may be mastered by means of strategies. Data on the ways technical writers compose were collected, and findings were related to the three areas of agreement. Questionnaires and interviews surveying 70 writers were used. The disciplines represented by these writers included civil, chemical, agricultural, geological, mechanical, electrical, and petroleum engineering, chemistry, hydrology, geology, and biology. Those providing consulting services, or performing research. No technical editors or professional writers were surveyed, only technicians, engineers, and researchers whose jobs involved composing reports. Three pedagogical implications are included.

  5. Shuttle payload interface verification equipment study. Volume 3: Specification data

    NASA Technical Reports Server (NTRS)

    1976-01-01

    A complete description is given of the IVE physical and performance design requirements as evolved in this study. The data are presented in a format to facilitate the development of an item specification. Data were used to support the development of the project plan data (schedules, cost, etc.) contained in Volume 4 of this report.

  6. Atmosphere explorer missions C, D, and E. Spacecraft experiment interface definition study

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The Atmosphere Explorer Missions C, D, & E Spacecraft/Experiment Interface Definition Study is discussed. The objectives of the study included an analysis of the accommodation requirements of the experiments for the three missions, an assessment of the overall effect of these requirements on the spacecraft system design and performance, and the detailed definition of all experiment/spacecraft electrical, mechanical, and environmental interfaces. In addition, the study included the identification and definition of system characteristics required to ensure compatibility with the consolidated STADAN and MSFN communications networks.

  7. Interstellar dust: interfacing laboratory, theoretical and observational studies

    NASA Astrophysics Data System (ADS)

    Jones, Anthony Peter

    2015-08-01

    In this talk I will consider how our understanding of interstellar dust can only be advanced through a combination of laboratory, theoretical and observational studies, which provide the critical framework for advancing our understanding. I will summarise what we currently know, or think we know, about the physical and compositional properties of dust and their evolution in interstellar media. Along the way I will question the utility of astronomical dust analogues and show, based on data from the laboratory, theoretical studies and from astronomical observations, that some of our prior interpretations need to be subjected to a critical re-evaluation. I will present interstellar dust modelling from a new vantage point and review ideas on the interpretation of observations within the framework of this model and its predictions for dust evolution within and between interstellar media. Finally, I will summarise some of the current outstanding issues and what we would like to learn in the future.

  8. On biomolecules and semiconductors: Analytical studies of interface dynamics

    NASA Astrophysics Data System (ADS)

    Slavin, John William Joseph

    The studies discussed here were undertaken to examine the use of III-V semiconducting materials as templates for biomolecules, to be applied in such technologies as Field-Effect Transistor (FET) and Light-emitting Diode (LED) biosensors. Materials application requires an informed analysis of interactions between chemical environments. Specific to surfaces, this means investigating the molecular interactions between the substrate and the bonding moieties. The analytical tools used to probe these interactions, and the changes that such communication causes on specific substrates are specifically discussed. Surface analysis tools included in this review are Atomic Force Microscopy (AFM), Nanoindentation, X-ray Photoelectron Spectroscopy (XPS), and Raman Microscopy. The interaction of biomolecules - deoxyribonucleic acid (DNA), proteins adhered to nanoparticles, and amino acids - on semiconductor surfaces is also examined. Proper investigation follows, as well, the methods of applying these biomolecular structures to the specified surfaces, through procedures such as solution phase transfer, as well as Dip-pen Nanolithography (DPN). The stretching and enzymatic cleavage of DNA, on silicon oxide surfaces, was studied to determine the recognition properties of dual-enzymatic systems on surfaces. Fundamental questions such as the interaction of functional groups with InAs(100) surfaces, the mechanical properties of protein modified systems, and the DPN application of biologically relevant linker molecules to InAs(100) surfaces were explored. These studies provide information applicable to the development of novel sensing platforms in the future.

  9. Interfacing anthropology and epidemiology: the Bedouin Arab Infant Feeding Study.

    PubMed

    Hundt, G A; Forman, M R

    1993-04-01

    This paper encapsulates a 10 year effort of multi-disciplinary research on the relationship between infant feeding, growth, and morbidity among the Negev Bedouin Arabs of Israel as they underwent a transition from semi-nomadism to urban settlement. The research team was multi-disciplinary including a nutritional epidemiologist and an anthropologist who both came to the study with previous experience in interdisciplinary work. The specific study objectives were (1) a description of infant feeding practices among Negev Bedouin Arab women at various stages of settlement, (2) an examination of the trend in these infant feeding practices, (3) a comparison of the extent to which different infant feeding practices are related to infant morbidity and growth after adjustment for exposure to social change and other covariates. The data collection took place in 1981-83 and the analysis from 1984-88. In this paper, two areas of the study are discussed in depth: the duration of exclusive breast feeding during the practice of the traditional postpartum 40 day rest period, and the development of a culture-specific scale of socioeconomic status. Through these examples, we highlight the use of ethnographic data and the merging of epidemiology and anthropology from hypothesis generation through data collection, data analysis and interpretation. PMID:8480241

  10. First principles study of band line up at defective metal-oxide interface: oxygen point defects at Al/SiO2 interface

    NASA Astrophysics Data System (ADS)

    Tea, Eric; Huang, Jianqiu; Hin, Celine

    2016-03-01

    The dielectric breakdown at metal-oxide interfaces is a critical electronic device failure mechanism. Electronic tunneling through dielectric layers is a well-accepted explanation for this phenomenon. Theoretical band alignment studies, providing information about tunneling, have already been conducted in the literature for metal-oxide interfaces. However, most of the time materials were assumed defect free. Oxygen vacancies being very common in oxides, their effect on band lineup is of prime importance in understanding electron tunneling in realistic materials and devices. This work explores the effect of oxygen vacancy and oxygen di-vacancy at the Al/SiO2 interface on the band line up within Density Functional Theory using PBE0 hybrid exchange and correlation functional. It is found that the presence of defects at the interface, and their charge state, strongly alters the band line up.

  11. A Qualitative Inquiry of Career Exploration in Highly Implemented Career and Technical Education Programs of Study

    ERIC Educational Resources Information Center

    Stipanovic, Natalie; Stringfield, Sam

    2013-01-01

    This qualitative study explores career counseling and guidance services as provided to students engaged in career and technical education programs at three sites in the United States. The sites, consisting of high schools and community colleges, were part of the National Research Center for Career and Technical Education's 5-year studies of…

  12. First-principles study of interface doping in ferroelectric junctions

    PubMed Central

    Wang, Pin-Zhi; Cai, Tian-Yi; Ju, Sheng; Wu, Yin-Zhong

    2016-01-01

    Effect of atomic monolayer insertion on the performance of ferroelectric tunneling junction is investigated in SrRuO3/BaTiO3/SrRuO3 heterostrucutures. Based on first-principles calculations, the atomic displacement, orbital occupancy, and ferroelectric polarization are studied. It is found that the ferroelectricity is enhanced when a (AlO2)− monolayer is inserted between the electrode SRO and the barrier BTO, where the relatively high mobility of doped holes effectively screen ferroelectric polarization. On the other hand, for the case of (LaO)+ inserted layer, the doped electrons resides at the both sides of middle ferroelectric barrier, making the ferroelectricity unfavorable. Our findings provide an alternative avenue to improve the performance of ferroelectric tunneling junctions. PMID:27063704

  13. Theoretical study of reactions at the electrode-electrolyte interface

    SciTech Connect

    Halley, J.W.

    1993-01-01

    Electron transfer rates are predicted by numerical methods, in a collaboration with Argonne National Laboratory . Emphasis is on electron transfer involving ions known to be important in enhancing stress corrosion cracking in light water reactors and on electron transfer at oxide surfaces. We have produced a new theory for description of the Jahn Teller effect in the solvation shell of the cuprous ion in aqueous solution, have implemented it in a molecular dynamics simulation and compared the results with experimental neutron scattering measurements on solutions containing the cuprous ion. A large amount of numerical data has been collected on the transition state of the ferrous ferric electron transfer reaction at an electrode. Work was completed on a polarizable and dissociable model of water for use in the electron transfer studies. New calculations of the conductivity in models of oxides have shown the existence of impurity conduction bands in such models for the first time.

  14. Wisconsin Indianhead Technical College Delphi Study. Final Report.

    ERIC Educational Resources Information Center

    Harkins, Arthur M.; Otto, Nelson R.

    A project was conducted to define positive, opportunity-focused methods to increase the percentage of high school students who are academically and personally prepared for enrollment in technical college directly after graduation. Objectives included determining how and why high school students choose to attend or not to attend vocational…

  15. Case Study: Randolph County Vocational Technical Center, Elkins, W. Va.

    ERIC Educational Resources Information Center

    Southern Regional Education Board, Atlanta, GA.

    Randolph County Vocational Technical Center, Elkins, West Virginia, received a grant in 1997 for a project that was part of the High Schools That Work (HSTW) initiative to improve academic skills of career-bound students. The superintendent and faculty knew that improving achievement meant reaching out to the three home high schools to bring them…

  16. Safety in earth orbit study. Volume 1: Technical summary

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A summary of the technical results and conclusions is presented of the hazards analyses of earth orbital operations in conjunction with the space shuttle program. The space shuttle orbiter and a variety of manned and unmanned payloads delivered to orbit by the shuttle are considered. The specific safety areas examined are hazardous payloads, docking, on-orbit survivability, tumbling spacecraft, and escape and rescue.

  17. Do Career and Technical Education Programs of Study Improve Student Achievement? Preliminary Analyses from a Rigorous Longitudinal Study

    ERIC Educational Resources Information Center

    Castellano, Marisa; Sundell, Kirsten; Overman, Laura T.; Aliaga, Oscar A.

    2012-01-01

    This longitudinal study examines the impact of programs of study on high school academic and technical achievement. Two districts are participating in experimental and quasi-experimental strands of the study. This article describes the sample selection, baseline characteristics, study design, career and technical education and academic achievement…

  18. An experimental study of recirculating flow through fluid sediment interfaces

    NASA Astrophysics Data System (ADS)

    Khalili, A.; Basu, A. J.; Pietrzyk, U.; Raffel, M.

    1999-03-01

    We report here visualizations and quantitative measurements of scalar transport, under the influence of rotation, through permeable sediments with an overlying fluid layer. The experimental set-up considered here is a stationary cylinder containing a fluid-saturated porous medium up to its midheight, with supernatant water on top. A rotating lid generates, in the upper fluid region, a flow that partially percolates into the porous layer below. The velocity field in the fluid layer is obtained using particle image velocimetry (PIV). Further, dye transport from the sediment is studied using two different techniques. The first one is positron emission tomography (PET), a non-invasive method which allowed us to ‘see’ through the opaque solid matrix, and to obtain full three-dimensional pictures of dye transport through the sediment. The second one is digital photographic visualization from outside, and subsequent image processing in order to obtain the near-wall dye-washout depth. The experimental data suggest that the temporal evolution of washout depth for different sediments follows near-logarithmic behaviour. This finding is of importance for the a priori estimation of the transport of fluid and other solute substances in sandy aquatic sediments.

  19. Iron oxide mineral-water interface reactions studied by AFM

    SciTech Connect

    Hawley, M.E.; Rogers, P.S.Z.

    1994-07-01

    Natural iron mineral surfaces have been examined in air by atomic force (AFM) and scanning tunneling (STM) microscopies. A number of different surface features were found to be characteristic of the native surface. Even surfaces freshly exposed by crushing larger crystals were found to have a pebbly surface texture caused by the presence of thin coatings of what might be surface precipitates. This finding is interpreted as evidence for previous exposure to water, probably through an extensive network of microfractures. Surface reactions on the goethite crystals were studied by AFM at size resolutions ranging from microns to atomic resolution before, during, and after reaction with distilled water and 0.lN HCl. Immediate and extensive surface reconfiguration occurred on contact with water. In one case, after equilibration with water for 3 days, surface reprecipitation, etching and pitting were observed. Atomic resolution images taken under water were found to be disordered. The result of surface reaction was generally to increase the surface area substantially through the extension of surface platelet arrays, present prior to reaction. This work is being done in support of the site characterization project at Yucca Mountain.

  20. Space shuttle/payload interface analysis (study 2.4). Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    Pritchard, E. I.

    1973-01-01

    The space shuttle/payload interface analysis is presented. The analysis consists of the following sections: (1) payload capture and cost analysis, (2) business risk and value of operations in space analysis, and (3) payload community analysis. The primary objective of the study was to furnish a method for tracing capture/cost analyses conducted by other study groups.

  1. Development of a submersible shadowgraph for the study of interfaces in salt-gradient solar ponds

    SciTech Connect

    Huacuz, J.M.; Sierra, F.; Venegas, C.; Ramos, C. )

    1989-01-01

    In this paper the processes of development and testing of a submersible shadowgraph are described. This instrument was devised as a tool for the study of interfaces in salt-gradient solar ponds. Tests were carried out in the solar pond of the University of Texas at El Paso. Photographs of interfaces inside the pond were taken for the first time. The submersible shadowgraph can be stationed inside the pond for time dependent studies of a given region, or it can be used to scan the pond depth.

  2. First principles studies of the stability and Shottky barriers of metal/CdTe(111) interfaces

    NASA Astrophysics Data System (ADS)

    Liu, Zhen; Miao, Masoehng; Kioussis, Nicholas; Aqariden, Fikri; Chang, Y.; Grein, Christoph

    CdZnTe and CdTe based semiconductor X-Ray and Gamma-Ray detectors have been intensively studied recently due to their promising potentials for achieving high-resolution, high signal-to-noise ratios and low leakage current, all are desirable features in applications ranging from medical diagnostics to homeland security. Using density functional calculations, we systematically studied the stability, the atomic and electronic structures of the interfaces between CdTe (111) surfaces (Cd- and Te-terminated) and the selected metals (Cu, Al Ni, Pd and Pt). We also calculated the Schottky barrier height (SBH) by aligning the electrostatic potentials in semiconductor and metal regions. Our calculations revealed significant differences between the Cd- and Te- terminated interfaces. While metals tend to deposit directly on reconstructed Te-terminated surfaces, they form a Te-metal alloy layer at the Cd-Terminated metal/CdTe interface. For both Te- and Cd- terminated interfaces, the Schottky barrier heights do not depend much on the choice of metals despite the large variation of the work functions. On the other hand, the interface structure is found to have large effect on the SBH, which is attributed to the metal induced states in the gap.

  3. Experimental Study of the Richtmyer-Meshkov Instability for a He -- SF6 Interface

    NASA Astrophysics Data System (ADS)

    Motl, Bradley; Ranjan, Devesh; Oakley, Jason; Anderson, Mark; Bonazza, Riccardo

    2007-11-01

    Results are presented from a series of experiments studying the Richtmyer-Meshkov (RM) instability for the case of a perturbed gas interface at the Wisconsin Shock Tube Laboratory. A membraneless interface is formed by the head-on flow of helium and sulfur-hexafluoride (seeded with smoke) which creates a stagnation surface. A sinusoidal interface is created at the gas stagnation plane in the test section by oscillating pistons that are initially flush with the shock tube walls. Flow visualization for the initial condition and post-shock images is carried out using Mie scattering from a planar laser sheet. The RM instability is studied for varying incident shock wave strengths (1.1 <=M <= 2), and results are reported in the form of experimental images and perturbation growth rates which are compared to several analytic models.

  4. Usefulness of O-18 and deuterium to study transport processes at aquatic interfaces

    NASA Astrophysics Data System (ADS)

    Lewandowski, Jörg; Pöschke, Franziska; Rudnick, Sebastian; Meinikmann, Karin; Périllon, Cécile

    2014-05-01

    Several different tracers are used in ecohydrology to study the manifold transport processes across groundwater-surface water interfaces. The stable isotopes of oxygen (O-18) and hydrogen (deuterium) as parts of the water molecule might be perfect tracers since their behavior in the environment is quite conservative. Isotope signatures of water differ due to origin of the water and can help to identify processes such as in- or exfiltration at groundwater-surface water interfaces. The recent development of cavity ring-down spectroscopy facilitates reliable measurements by far compared to the previously common method of mass spectroscopy. Nowadays, stable isotope measurements are orders of magnitude cheaper, faster and easier than five years ago. Based on that analytical progress, an increasing number of studies employ the stable isotopes O-18 and deuterium. Ecohydrological applications and their limitations are critically discussed in this contribution focusing on aquifer-lake interfaces.

  5. Experimental study on interface region of two-dimensional Si layers by forming gas annealing

    NASA Astrophysics Data System (ADS)

    Mizuno, Tomohisa; Suzuki, Yuhya; Kikuchi, Reika; Suzuki, Ayaka; Inoue, Ryohsuke; Yamanaka, Masahiro; Yokoyama, Miki; Nagamine, Yoshiki; Aoki, Takashi; Maeda, Tatsuro

    2016-04-01

    We experimentally studied the SiO2/Si and Si/buried oxide (BOX) interface regions of a two-dimensional (2D) Si layer, by forming gas annealing (FGA). A photoluminescence (PL) result measured at various lattice temperature, T L, values shows that the PL intensity I PL of the 2D-Si layer rapidly increases and then saturates with increasing FGA temperature, T A, and time, t A. I PL also increases with decreasing T L. A one-dimensional (1D) Schroedinger equation simulator indicates that some of the electrons in the 2D-Si layer generated by a PL excitation laser are quantum-mechanically transmitted into Si interface regions. Actually, we experimentally confirmed that the PL spectra of the 2D-Si layer can be fitted by the PL emission from two regions with different PL peak photon energy values, E PH, which consist of a typical 2D-Si and the interface regions of both the surface SiO2/Si and Si/BOX. Thus, this forming gas dependence is probably attributable to the improved lifetime τ of electrons in the surface interface region, because the Si surface is terminated by H atoms. Moreover, the E PH of the interface region is higher than that of the 2D-Si layer, because of the graded increased bandgap in the interface regions. However, the E PH of 2D-Si is independent of both T A and T L, and this T L independence does not agree with that of a 3D-Si layer. Consequently, we experimentally verified the larger impact of the Si interface on the performance of 2D-Si layer.

  6. First-principles study of Mg(0001)/MgO(1-11) interfaces

    NASA Astrophysics Data System (ADS)

    Song, Hong-Quan; Zhao, Ming; Li, Jian-Guo

    2016-06-01

    By means of first-principles density-functional calculations, we studied the surface energy of a nonstoichiometric MgO(1-11) slab, the interfacial energy and interfacial bonding characteristics of Mg-terminated and O-terminated Mg/MgO(1-11) interfaces with three stacking-site (TOP, HCP and FCC sites) models, and the effect of the thickness of Mg films on the O-terminated MgO(1-11) surface. The results indicate that the surface energies of the nonstoichiometric MgO(1-11) slab and interfacial energies of Mg/Mg(1-11) interface depend on Mg chemical potential. We found that the Mg-terminated MgO(1-11) surface is more stable than the O-terminated MgO(1-11) surface at high Mg chemical potential, and Mg/MgO(1-11) with FCC stacking-site model is the most stable configuration in the Mg/MgO(1-11) interfaces. The results of the electronic structure reveals that the interfacial bonding of Mg-terminated interface with FCC site model mainly consists of metallic bond and of the O-terminated interface with FCC site model is mainly ionic with a small degree of σ-type covalent bond. Although the interfacial energy of Mg-terminated Mg/MgO interface with FCC stacking-site model is slightly higher than that of O-terminated Mg/MgO interface, the molten Mg would epitaxially grow on the FCC sites of the Mg-terminated MgO(1-11) surface because of the high evaporation pressure of Mg at high temperature.

  7. Technical Work Plan for: Fracture and Lithophysal Studies

    SciTech Connect

    n

    2006-09-11

    The primary objective of the work scope described in this technical work plan (TWP) is to enhance the descriptions of fracture and lithophysal parameters for the repository host horizon (RHH) over the repository footprint utilizing a predictive model. This work is planned to address U.S. Nuclear Regulatory Commission (NRC) additional information needs (AINs) associated with the Structural Deformation and Seismicity (SDS) Key Technical Issues (KTI) agreement SDS 3.03 (Schlueter 2000 [DIRS 166615]). The results of the planned work are expected to enhance the technical basis and confirm the results of the fracture analyses presented in ''Drift Degradation Analysis'' (BSC 2004 [DIRS 166107], Section 6.1.6). This model is not intended to provide an alternative for the unsaturated zone and saturated zone flow and transport models currently used by the Yucca Mountain Project (YMP). Nor are the outputs of this model intended to address the SDS 3.03 AINs related to the unsaturated zone and saturated zone flow and transport models.

  8. 76 FR 72885 - FM Asymmetric Sideband Operation and Associated Technical Studies

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-28

    ... Documents in Rulemaking Proceedings, 63 FR 24121 (1998). Electronic Filers: Comments may be filed... COMMISSION 47 CFR Part 73 FM Asymmetric Sideband Operation and Associated Technical Studies AGENCY: Federal... for public comment on this request and on two related technical reports. DATES: Comments for...

  9. At-Risk Learner Preference in Engineering/Technical Graphics: An Exploratory Study

    ERIC Educational Resources Information Center

    Ernst, Jeremy V.

    2011-01-01

    This exploratory study investigated learner preferences of secondary Career and Technical Education (CTE) Engineering/Technical Graphics students using the VARK Questionnaire. The VARK Questionnaire is an instrument that assists in determining students' dominant preferred learning styles, whether visual, aural, reading, or kinesthetic. This study…

  10. Interviewing of Technical Communicators: A Field Study Method for Teacher Preparation.

    ERIC Educational Resources Information Center

    Goldstein, Jone Rymer

    The exploratory interview is one field method for studying how professionals write as part of their jobs that is also an effective device for preparing composition instructors to teach technical writing. This field research method is a loosely guided discussion in which the technical communicator ranges freely, widely, and in depth about personal…

  11. Michigan Technician Need Study. The Present and Projected Demand for Technically Trained People in Michigan.

    ERIC Educational Resources Information Center

    Ferris State Coll., Big Rapids, MI. Office of Administrative Studies.

    This study undertakes to determine (1) the extent of crucial manpower shortages in Michigan by technical area and skill, by the areas of occupation or industry, and whether these shortages will decrease or increase over the next few years, and (2) the opportunities for technical education now available or necessary to assure Michigan industry and…

  12. Thermodynamic Study of the Role of Interface Curvature on Multicomponent Vapor-Liquid Phase Equilibrium.

    PubMed

    Shardt, Nadia; Elliott, Janet A W

    2016-04-14

    The effect of interface curvature on phase equilibrium has been much more studied for single-component than multicomponent systems. We isolate the effect of curvature on multicomponent vapor-liquid equilibrium (VLE) phase envelopes and phase composition diagrams using the ideal system methanol/ethanol and the nonideal system ethanol/water as illustrative examples. An important finding is how nanoscale interface curvature shifts the azeotrope (equal volatility point) of nonideal systems. Understanding of the effect of curvature on VLE can be exploited in future nanoscale prediction and design. PMID:27028744

  13. Theoretical study of vibrational energy transfer of free OH groups at the water-air interface

    NASA Astrophysics Data System (ADS)

    Zheng, Renhui; Wei, Wenmei; Sun, Yuanyuan; Song, Kai; Shi, Qiang

    2016-04-01

    Recent experimental studies have shown that the vibrational dynamics of free OH groups at the water-air interface is significantly different from that in bulk water. In this work, by performing molecular dynamics simulations and mixed quantum/classical calculations, we investigate different vibrational energy transfer pathways of free OH groups at the water-air interface. The calculated intramolecular vibrational energy transfer rate constant and the free OH bond reorientation time scale agree well with the experiment. It is also found that, due to the small intermolecular vibrational couplings, the intermolecular vibrational energy transfer pathway that is very important in bulk water plays a much less significant role in the vibrational energy relaxation of the free OH groups at the water-air interface.

  14. A novel X-ray photoelectron spectroscopy study of the Al/SiO2 interface

    NASA Technical Reports Server (NTRS)

    Hecht, M. H.; Vasquez, R. P.; Grunthaner, F. J.; Zamani, N.; Maserjian, J.

    1985-01-01

    The nondestructive measurement of the chemical and physical characteristics of the interface between bulk SiO2 and thick aluminum films is reported. Both X-ray phototelectron spectroscopy (XPS) and electrical measurements of unannealed, resistively evaporated Al films on thermal SiO2 indicate an atomically abrupt interface. Post metallization annealing at 450 C induces reduction of the SiO2 by the aluminum, at a rate consistent with the bulk reaction rate. The XPS measurement is performed from the SiO2 side after the removal of the Si substrate with XeF2 gas and thinning of the SiO2 layer with HF:ETOH. This represents a powerful new approach to the study of metal-insulator and related interfaces.

  15. Theoretical study of vibrational energy transfer of free OH groups at the water-air interface.

    PubMed

    Zheng, Renhui; Wei, Wenmei; Sun, Yuanyuan; Song, Kai; Shi, Qiang

    2016-04-14

    Recent experimental studies have shown that the vibrational dynamics of free OH groups at the water-air interface is significantly different from that in bulk water. In this work, by performing molecular dynamics simulations and mixed quantum/classical calculations, we investigate different vibrational energy transfer pathways of free OH groups at the water-air interface. The calculated intramolecular vibrational energy transfer rate constant and the free OH bond reorientation time scale agree well with the experiment. It is also found that, due to the small intermolecular vibrational couplings, the intermolecular vibrational energy transfer pathway that is very important in bulk water plays a much less significant role in the vibrational energy relaxation of the free OH groups at the water-air interface. PMID:27083739

  16. Geochemical Insight from Nonlinear Optical Studies of Mineral-Water Interfaces

    NASA Astrophysics Data System (ADS)

    Covert, Paul A.; Hore, Dennis K.

    2016-05-01

    The physics and chemistry of mineral-water interfaces are complex, even in idealized systems. Our need to understand this complexity is driven by both pure and applied sciences, that is, by the need for basic understanding of earth systems and for the knowledge to mitigate our influences upon them. The second-order nonlinear optical techniques of second-harmonic generation and sum-frequency generation spectroscopy have proven adept at probing these types of interfaces. This review focuses on the contributions to geochemistry made by nonlinear optical methods. The types of questions probed have included a basic description of the structure adopted by water molecules at the mineral interface, how flow and porosity affect this structure, adsorption of trace metal and organic species, and dissolution mechanisms. We also discuss directions and challenges that lie ahead and the outlook for the continued use of nonlinear optical methods for studies of mineral-water boundaries.

  17. NiAl(110)/Cr(110) interface: A density functional theory study

    NASA Astrophysics Data System (ADS)

    Liu, W.; Li, J. C.; Zheng, W. T.; Jiang, Q.

    2006-05-01

    The optimal geometries, thermodynamic properties, and electronic structures of NiAl(110)/Cr(110) interface are studied using a first-principle density functional plane-wave ultrasoft pseudopotential method. Surface energies of different NiAl surfaces are compared with those obtained based on the classical broken-bond rule. Simulation results indicate that the structure of Ni and Al placed in the hollow sites of Cr atoms at the interface is more thermodynamically stable, and the NiCr bonding is dominated by 3d electrons of Ni and Cr. It is found that NiAl(110)/Cr(110) alloying could lower brittleness of NiAl compounds. With simulated values of adhesion work and interface energy for NiAl(110)/Cr(110) system, its mechanical and thermodynamic properties are also discussed.

  18. Atomic Scale Study of Interfaces Involved in Epitaxial Fe/MgO/Fe Magnetic Tunnel Junctions

    SciTech Connect

    Andrieu, S.; Serra, R.; Bonell, F.; Tiusan, C.; Calmels, L.; Snoeck, E.; Varela del Arco, Maria; Pennycook, Stephen J; Walls, M.; Colliex, C.

    2009-01-01

    Epitaxial Fe/MgO/Fe(001) magnetic tunnel junctions grown by Molecular Beam Epitaxy have been studied by using spatially resolved Electron Energy Loss Spectroscopy (EELS). The structure, the chemical composition as well as the bonding variations across the interfaces were investigated up to the atomic scale.

  19. An experimental study of liquid drop - interface coalescence in the presence of surfactants

    NASA Astrophysics Data System (ADS)

    Angeli, Panagiota; Chinaud, Maxime; Li, Kai; Wang, Wei; University College London Team; Beijing Key Laboratory of Urban Oil; Gas Distribution Technology Team

    2014-11-01

    Drop-interface coalescence has been the subject of many studies both theoretical and experimental. It is of particular interest for the oil industries particularly during the transportation of multiphase mixtures where coalescence rates can affect the stability and separation of dispersions. It is well-known that the presence of surfactants can significantly affect the coalescence rates. In this work a silicon oil -water system has been studied in a rectangular coalescence cell. Both rising oil drops and falling water drops coalescing with the water-oil interface have been investigated. A water soluble surfactant, SPAN 80, was used. High speed imaging has been performed to study the coalescence phenomenon and obtain the coalescence time of the drops with the interface with and without the presence of the surfactant. The velocity fields in the bulk fluid and in the liquid film forming between the drop and the interface were studied with shadowgraphy (bright field Particle Image Velocimetry). To increase the spatial resolution particularly in the liquid film microscope lenses were implemented. Results have been compared against existing literature.

  20. Does Interface Matter? A Study of Web Authoring and Editing by Inexperienced Web Writers

    ERIC Educational Resources Information Center

    Dick, Rodney F.

    2006-01-01

    This study explores the complicated nature of the interface as a mediational tool for inexperienced writers as they composed hypertext documents. Because technology can become so quickly and inextricably connected to people's everyday lives, it is essential to explore the effects on these technologies before they become invisible. Because…

  1. Final Technical Report for the Energy Frontier Research Center Understanding Charge Separation and Transfer at Interfaces in Energy Materials (EFRC:CST)

    SciTech Connect

    Vanden Bout, David A.

    2015-09-14

    Our EFRC was founded with the vision of creating a broadly collaborative and synergistic program that would lead to major breakthroughs in the molecular-level understanding of the critical interfacial charge separation and charge transfer (CST) processes that underpin the function of candidate materials for organic photovoltaic (OPV) and electrical-energy-storage (EES) applications. Research in these energy contexts shares an imposing challenge: How can we understand charge separation and transfer mechanisms in the presence of immense materials complexity that spans multiple length scales? To address this challenge, our 50-member Center undertook a total of 28 coordinated research projects aimed at unraveling the CST mechanisms that occur at interfaces in these nanostructured materials. This rigorous multi-year study of CST interfaces has greatly illuminated our understanding of early-timescale processes (e.g., exciton generation and dissociation dynamics at OPV heterojunctions; control of Li+-ion charging kinetics by surface chemistry) occurring in the immediate vicinity of interfaces. Program outcomes included: training of 72 graduate student and postdoctoral energy researchers at 5 institutions and spanning 7 academic disciplines in science and engineering; publication of 94 peer-reviewed journal articles; and dissemination of research outcomes via 340 conference, poster and other presentations. Major scientific outcomes included: implementation of a hierarchical strategy for understanding the electronic communication mechanisms and ultimate fate of charge carriers in bulk heterojunction OPV materials; systematic investigation of ion-coupled electron transfer processes in model Li-ion battery electrode/electrolyte systems; and the development and implementation of 14 unique technologies and instrumentation capabilities to aid in probing sub-ensemble charge separation and transfer mechanisms.

  2. Oxide surfaces and metal/oxide interfaces studied by grazing incidence X-ray scattering

    NASA Astrophysics Data System (ADS)

    Renaud, Gilles

    important physical properties such as superconductivity or magnetism is also briefly reviewed. The strengths and limitations of the technique, such as the need for single crystals and surfaces of high crystalline quality are discussed. Finally, an outlook of future prospects in the field is given, such as the study of more complex oxide surfaces, vicinal surfaces, reactive metal/oxide interfaces, metal oxidation processes, the use of surfactants to promote wetting of a metal deposited on an oxide surface or the study of oxide/liquid interfaces in a non-UHV environment.

  3. Design and usability study of an iconic user interface to ease information retrieval of medical guidelines

    PubMed Central

    Griffon, Nicolas; Kerdelhué, Gaétan; Hamek, Saliha; Hassler, Sylvain; Boog, César; Lamy, Jean-Baptiste; Duclos, Catherine; Venot, Alain; Darmoni, Stéfan J

    2014-01-01

    Background and objective Doc'CISMeF (DC) is a semantic search engine used to find resources in CISMeF-BP, a quality controlled health gateway, which gathers guidelines available on the internet in French. Visualization of Concepts in Medicine (VCM) is an iconic language that may ease information retrieval tasks. This study aimed to describe the creation and evaluation of an interface integrating VCM in DC in order to make this search engine much easier to use. Methods Focus groups were organized to suggest ways to enhance information retrieval tasks using VCM in DC. A VCM interface was created and improved using the ergonomic evaluation approach. 20 physicians were recruited to compare the VCM interface with the non-VCM one. Each evaluator answered two different clinical scenarios in each interface. The ability and time taken to select a relevant resource were recorded and compared. A usability analysis was performed using the System Usability Scale (SUS). Results The VCM interface contains a filter based on icons, and icons describing each resource according to focus group recommendations. Some ergonomic issues were resolved before evaluation. Use of VCM significantly increased the success of information retrieval tasks (OR=11; 95% CI 1.4 to 507). Nonetheless, it took significantly more time to find a relevant resource with VCM interface (101 vs 65 s; p=0.02). SUS revealed ‘good’ usability with an average score of 74/100. Conclusions VCM was successfully implemented in DC as an option. It increased the success rate of information retrieval tasks, despite requiring slightly more time, and was well accepted by end-users. PMID:24650636

  4. First principles studies of the stability and Shottky barriers of metal/CdTe(111) interfaces

    NASA Astrophysics Data System (ADS)

    Dorj, Odkhuu; Miao, M. S.; Kioussis, N.; Tari, S.; Aqariden, F.; Chang, Y.; Grein, C.

    2015-03-01

    CdZnTe and CdTe based semiconductor X-Ray and Gamma-Ray detectors have been intensively studied recently due to their promising potentials for achieving high-resolution, high signal-to-noise ratios and low leakage current, all are desirable features in applications ranging from medical diagnostics to homeland security. Understanding the atomic and electronic structures of the metal/semiconductor interfaces is essential for the further improvements of performance. Using density functional calculations, we systematically studied the stability, the atomic and electronic structures of the interfaces between Cd-terminated CdTe (111) surface and the selected metals. We also calculated the Schottky barrier height (SBH) by aligning the electrostatic potentials in semiconductor and metal regions. Our calculations revealed the importance of intermixing between semiconductor and metal layers and the formation of Te-metal alloys at the interface. The obtained SBH does not depend much on the choice of metals despite the large variation of the work functions. On the other hand, the interface structure is found to have large effect to the SBH, which is attributed to the metal induced states in the gap. The position of such states is insensitive to the metal work functions, as revealed by the analysis of the electronic structures.

  5. Reactive ZnO/Ti/ZnO interfaces studied by hard x-ray photoelectron spectroscopy

    SciTech Connect

    Knut, Ronny Lindblad, Rebecka; Rensmo, Håkan; Karis, Olof; Grachev, Sergey; Faou, Jean-Yvon; Søndergård, Elin

    2014-01-28

    The chemistry and intermixing at buried interfaces in sputter deposited ZnO/Ti/ZnO thin layers were studied by hard x-ray photoelectron spectroscopy. The long mean free path of the photoelectrons allowed for detailed studies of the oxidation state, band bending effects, and intrinsic doping of the buried interfaces. Oxidation of the Ti layer was observed when ZnO was deposited on top. When Ti is deposited onto ZnO, Zn Auger peaks acquire a metallic character indicating a strong reduction of ZnO at the interface. Annealing of the stack at 200 °C results in further reduction of ZnO and oxidation of Ti. Above 300 °C, oxygen transport from the bulk of the ZnO layer takes place, leading to re-oxidation of ZnO at the interface and further oxidation of Ti layer. Heating above 500 °C leads to an intermixing of the layers and the formation of a Zn{sub x}TiO{sub y} compound.

  6. Density functional theory based study of chlorine doped WS2-metal interface

    NASA Astrophysics Data System (ADS)

    Chanana, Anuja; Mahapatra, Santanu

    2016-03-01

    Investigation of a transition metal dichalcogenide (TMD)-metal interface is essential for the effective functioning of monolayer TMD based field effect transistors. In this work, we employ the Density Functional Theory calculations to analyze the modulation of the electronic structure of monolayer WS2 with chlorine doping and the relative changes in the contact properties when interfaced with gold and palladium. We initially examine the atomic and electronic structures of pure and doped monolayer WS2 supercell and explore the formation of midgap states with band splitting near the conduction band edge. Further, we analyze the contact nature of the pure supercell with Au and Pd. We find that while Au is physiosorbed and forms n-type contact, Pd is chemisorped and forms p-type contact with a higher valence electron density. Next, we study the interface formed between the Cl-doped supercell and metals and observe a reduction in the Schottky barrier height (SBH) in comparison to the pure supercell. This reduction found is higher for Pd in comparison to Au, which is further validated by examining the charge transfer occurring at the interface. Our study confirms that Cl doping is an efficient mechanism to reduce the n-SBH for both Au and Pd, which form different types of contact with WS2.

  7. A Study of Technical Engineering Peer Reviews at NASA

    NASA Technical Reports Server (NTRS)

    Chao, Lawrence P.; Tumer, Irem Y.; Bell, David G.

    2003-01-01

    This report describes the state of practices of design reviews at NASA and research into what can be done to improve peer review practices. There are many types of reviews at NASA: required and not, formalized and informal, programmatic and technical. Standing project formal reviews such as the Preliminary Design Review and Critical Design Review are a required part of every project and mission development. However, the technical, engineering peer reviews that support teams' work on such projects are informal, some times ad hoc, and inconsistent across the organization. The goal of this work is to identify best practices and lessons learned from NASA's experience, supported by academic research and methodologies to ultimately improve the process. This research has determined that the organization, composition, scope, and approach of the reviews impact their success. Failure Modes and Effects Analysis (FMEA) can identify key areas of concern before or in the reviews. Product definition tools like the Project Priority Matrix, engineering-focused Customer Value Chain Analysis (CVCA), and project or system-based Quality Function Deployment (QFD) help prioritize resources in reviews. The use of information technology and structured design methodologies can strengthen the engineering peer review process to help NASA work towards error-proofing the design process.

  8. Technical Communications in Aeronautics: Results of an Exploratory Study. An Analysis of Profit Managers' and Nonprofit Managers' Responses. NASA Technical Memorandum 101626.

    ERIC Educational Resources Information Center

    Pinelli, Thomas E.; And Others

    Data collected from an exploratory study concerned with the technical communications practices of aerospace engineers and scientists were analyzed to test the primary assumption that profit and nonprofit managers in the aerospace community have different technical communications practices. Profit and nonprofit managers were compared in five…

  9. A theoretical study of wave dispersion and thermal conduction for HMX/additive interfaces

    NASA Astrophysics Data System (ADS)

    Long, Yao; Chen, Jun

    2014-04-01

    The wave dispersion rule for non-uniform material is useful for ultrasonic inspection and engine life prediction, and also is key in achieving an understanding of the energy dissipation and thermal conduction properties of solid material. On the basis of linear response theory and molecular dynamics, we derive a set of formulas for calculating the wave dispersion rate of interface systems, and study four kinds of interfaces inside plastic bonded explosives: HMX/{HMX, TATB, F2312, F2313}. (HMX: octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine; TATB: 1,3,5-triamino-2,4,6-trinitrobenzene; F2312, F2313: fluoropolymers). The wave dispersion rate is obtained over a wide frequency range from kHz to PHz. We find that at low frequency, the rate is proportional to the square of the frequency, and at high frequency, the rate couples with the molecular vibration modes at the interface. By using the results, the thermal conductivities of HMX/additive interfaces are derived, and a physical model is built for describing the total thermal conductivity of mixture explosives, including HMX multi-particle systems and {TATB, F2312, F2313}-coated HMX.

  10. A Study of Fluid Interface Configurations in Exploration Vehicle Propellant Tanks

    NASA Technical Reports Server (NTRS)

    Zimmerli, Gregory A.; Asipauskas, Marius; Chen, Yongkang; Weislogel, Mark M.

    2010-01-01

    The equilibrium shape and location of fluid interfaces in spacecraft propellant tanks while in low-gravity is of interest to system designers, but can be challenging to predict. The propellant position can affect many aspects of the spacecraft such as the spacecraft center of mass, response to thruster firing due to sloshing, liquid acquisition, propellant mass gauging, and thermal control systems. We use Surface Evolver, a fluid interface energy minimizing algorithm, to investigate theoretical equilibrium liquid-vapor interfaces for spacecraft propellant tanks similar to those that have been considered for NASA's new class of Exploration vehicles. The choice of tank design parameters we consider are derived from the NASA Exploration Systems Architecture Study report. The local acceleration vector employed in the computations is determined by estimating low-Earth orbit (LEO) atmospheric drag effects and centrifugal forces due to a fixed spacecraft orientation with respect to the Earth or Moon, and rotisserie-type spacecraft rotation. Propellant/vapor interface positions are computed for the Earth Departure Stage and Altair lunar lander descent and ascent stage tanks for propellant loads applicable to LEO and low-lunar orbit. In some of the cases investigated the vapor ullage bubble is located at the drain end of the tank, where propellant management device hardware is often located.

  11. Study of natural convection and interface shape in directional solidification of succinonitrile

    NASA Technical Reports Server (NTRS)

    Kawaji, M.; Ojah, M.; Stojanovic, M.; De Groh, H. C.

    1992-01-01

    Flow visualization experiments in a Bridgman furnace at zero growth velocity have been performed. The experiments were intended to investigate if the photochromic dye activation method could be used in a crystal growth study. The results from this work have confirmed that with a carefully designed experimental setup, the photochromic-dye method permits qualitative and quantitative evaluation of the flow field near the interface in crystal growth experiments. For the horizontal orientation of a 6 mm x 6 mm ampoule and an axial temperature gradient of 26.5 C/cm, velocity profiles have been obtained accurately at various positions near the interface. The maximum velocity of 1.29 mm/sec was measured in the central vertical plane and the flow was symmetrical about that plane. A flow inversion point was also noted, above which the flow was towards the interface and below it, away from the interface. The results obtained are useful for validating 3-dimensional numerical models and establishing a link between the macroscopic processing conditions and the formation of crystalline defects.

  12. First principles study of Al/SrTiO3 interface formation

    NASA Astrophysics Data System (ADS)

    Hamze, Ali; Posadas, Agham; Kormondy, Kristy; Demkov, Alexander

    Two-dimensional electron gasses (2DEGs) at the interfaces of oxides have been the subject of much interest in recent years due to their relatively high carrier mobilities and potential for use in all-oxide devices. In particular, the γ-Al2O3 (γ-alumina)-SrTiO3 (STO) system has been the focus of much research. It exhibits a 2DEG at the interface with a carrier mobility ranging from 103-105 cm2V-1 s-1, depending on the thickness of the STO and how the γ-alumina film was grown. It is believed that Al atoms steal oxygen from the STO substrate at growth temperature and thus create a conductive channel in STO near the interface. We investigate the initial studies of the interface formation using density functional theory. The results of first principles calculations are compared with those of x-ray photoemission spectroscopy (XPS) performed in situ on thin Al films deposited on STO by molecular beam epitaxy. Analysis of the Al 2p XPS spectrum shows one layer of aluminum is fully oxidized during growth at 40°C and 4 layers of aluminum are fully oxidized during growth at 600°C. Furthermore, the Ti 2p XPS spectrum shows the titanium atoms are reduced, which is consistent with the presence of oxygen vacancies in STO.

  13. Experimental Study of the Richtmyer-Meshkov Instability on a Coupled Multimode and Inclined Interface Perturbation

    NASA Astrophysics Data System (ADS)

    Reilly, David; Creel, Skylar; McFarland, Jacob; Mitruka, Jatin; McDonald, Christopher; Ranjan, Devesh

    2013-11-01

    The inclined shock tube in the Texas A&M Shock Tube and Advanced Mixing Laboratory was used to study the effect of small amplitude, long wavelength multimode perturbations imposed on the inclined interface initial condition of the Richtmyer-Meshkov instability. The inclined interface is essentially a long wavelength, extremely large amplitude perturbation. Images of the shocked flow-field were captured with the angle of the shock tube with respect to the horizontal at 60° (η/ λ = √{ 3}/6). The modal content of the initial conditions was determined by taking the Fourier decomposition of the interface. This work is a proof of concept for creating a coupled multimode and inclined interface. Work that is currently underway will investigate the effect of these initial conditions on intermediate and late-time mixing as well as the transition to turbulence before reshock by using qualitative comparisons of Mie scattering images, mixing width measurements, and circulation from Particle Image Velocimetry (PIV). This research was funded by the Air Force Office of Scientific Research Young Investigator Research Program (AFOSR-YIP) grant.

  14. Molecular dynamics study on condensation/evaporation coefficients of chain molecules at liquid–vapor interface

    SciTech Connect

    Nagayama, Gyoko Takematsu, Masaki; Mizuguchi, Hirotaka; Tsuruta, Takaharu

    2015-07-07

    The structure and thermodynamic properties of the liquid–vapor interface are of fundamental interest for numerous technological implications. For simple molecules, e.g., argon and water, the molecular condensation/evaporation behavior depends strongly on their translational motion and the system temperature. Existing molecular dynamics (MD) results are consistent with the theoretical predictions based on the assumption that the liquid and vapor states in the vicinity of the liquid–vapor interface are isotropic. Additionally, similar molecular condensation/evaporation characteristics have been found for long-chain molecules, e.g., dodecane. It is unclear, however, whether the isotropic assumption is valid and whether the molecular orientation or the chain length of the molecules affects the condensation/evaporation behavior at the liquid–vapor interface. In this study, MD simulations were performed to study the molecular condensation/evaporation behavior of the straight-chain alkanes, i.e., butane, octane, and dodecane, at the liquid–vapor interface, and the effects of the molecular orientation and chain length were investigated in equilibrium systems. The results showed that the condensation/evaporation behavior of chain molecules primarily depends on the molecular translational energy and the surface temperature and is independent of the molecular chain length. Furthermore, the orientation at the liquid–vapor interface was disordered when the surface temperature was sufficiently higher than the triple point and had no significant effect on the molecular condensation/evaporation behavior. The validity of the isotropic assumption was confirmed, and we conclude that the condensation/evaporation coefficients can be predicted by the liquid-to-vapor translational length ratio, even for chain molecules.

  15. Molecular dynamics study on condensation/evaporation coefficients of chain molecules at liquid-vapor interface

    NASA Astrophysics Data System (ADS)

    Nagayama, Gyoko; Takematsu, Masaki; Mizuguchi, Hirotaka; Tsuruta, Takaharu

    2015-07-01

    The structure and thermodynamic properties of the liquid-vapor interface are of fundamental interest for numerous technological implications. For simple molecules, e.g., argon and water, the molecular condensation/evaporation behavior depends strongly on their translational motion and the system temperature. Existing molecular dynamics (MD) results are consistent with the theoretical predictions based on the assumption that the liquid and vapor states in the vicinity of the liquid-vapor interface are isotropic. Additionally, similar molecular condensation/evaporation characteristics have been found for long-chain molecules, e.g., dodecane. It is unclear, however, whether the isotropic assumption is valid and whether the molecular orientation or the chain length of the molecules affects the condensation/evaporation behavior at the liquid-vapor interface. In this study, MD simulations were performed to study the molecular condensation/evaporation behavior of the straight-chain alkanes, i.e., butane, octane, and dodecane, at the liquid-vapor interface, and the effects of the molecular orientation and chain length were investigated in equilibrium systems. The results showed that the condensation/evaporation behavior of chain molecules primarily depends on the molecular translational energy and the surface temperature and is independent of the molecular chain length. Furthermore, the orientation at the liquid-vapor interface was disordered when the surface temperature was sufficiently higher than the triple point and had no significant effect on the molecular condensation/evaporation behavior. The validity of the isotropic assumption was confirmed, and we conclude that the condensation/evaporation coefficients can be predicted by the liquid-to-vapor translational length ratio, even for chain molecules.

  16. Steel: Reducing BOF Hood Scrubber Energy Costs at a Steel Mill (Technical Case Study)

    SciTech Connect

    Ericksen, E.

    1999-01-27

    This OIT Technical Case Study reveals how Bethlehem Steel Corporation, by installing a variable-frequency drive and making associated equipment modifications, was able to save energy, reduce operational costs, and decrease system maintenance.

  17. Fort Hood solar cogeneration facility conceptual design study. Volume 1. Technical report. Final technical report

    SciTech Connect

    Not Available

    1981-08-01

    A central receiver cogeneration facility is studied for a Texas military facility. A solar-heated heat-transfer salt provides heat to a steam generator and providing space heating and air conditioning and hot water for the complex. The site and its climate are described briefly. Candidate site-specific system configurations, technology assessments, system sizing, and the results of numerous trade studies leading toward the selection of the preferred system configuration are presented. A system level conceptual design of the cogeneration facility is presented, and the conceptual design of the major subsystems (heliostats, receiver, tower, energy transport and storage, fossil energy subsystem, electric power generation subsystem, control, space conditioning and domestic hot water subsystem) are described. Results of the economic analysis of the cogeneration facility are presented, including a description of analysis methods used, assumptions and rationale, simulation models used, a brief summary of capital and operations and maintenance costs, fuel savings, results of the economic evaluations and an economic scenario for future applications. The results of the development planning are presented, including all major activities required during the detailed design, construction, and initial operational phases. An assessment of the proposed facility by the Department of the Army at Fort Hood is presented. (LEW)

  18. Advanced Risk Reduction Tool (ARRT) Special Case Study Report: Science and Engineering Technical Assessments (SETA) Program

    NASA Technical Reports Server (NTRS)

    Kirsch, Paul J.; Hayes, Jane; Zelinski, Lillian

    2000-01-01

    This special case study report presents the Science and Engineering Technical Assessments (SETA) team's findings for exploring the correlation between the underlying models of Advanced Risk Reduction Tool (ARRT) relative to how it identifies, estimates, and integrates Independent Verification & Validation (IV&V) activities. The special case study was conducted under the provisions of SETA Contract Task Order (CTO) 15 and the approved technical approach documented in the CTO-15 Modification #1 Task Project Plan.

  19. A New Socio-technical Model for Studying Health Information Technology in Complex Adaptive Healthcare Systems

    PubMed Central

    Sittig, Dean F.; Singh, Hardeep

    2011-01-01

    Conceptual models have been developed to address challenges inherent in studying health information technology (HIT). This manuscript introduces an 8-dimensional model specifically designed to address the socio-technical challenges involved in design, development, implementation, use, and evaluation of HIT within complex adaptive healthcare systems. The 8 dimensions are not independent, sequential, or hierarchical, but rather are interdependent and interrelated concepts similar to compositions of other complex adaptive systems. Hardware and software computing infrastructure refers to equipment and software used to power, support, and operate clinical applications and devices. Clinical content refers to textual or numeric data and images that constitute the “language” of clinical applications. The human computer interface includes all aspects of the computer that users can see, touch, or hear as they interact with it. People refers to everyone who interacts in some way with the system, from developer to end-user, including potential patient-users. Workflow and communication are the processes or steps involved in assuring that patient care tasks are carried out effectively. Two additional dimensions of the model are internal organizational features (e.g., policies, procedures, and culture) and external rules and regulations, both of which may facilitate or constrain many aspects of the preceding dimensions. The final dimension is measurement and monitoring, which refers to the process of measuring and evaluating both intended and unintended consequences of HIT implementation and use. We illustrate how our model has been successfully applied in real-world complex adaptive settings to understand and improve HIT applications at various stages of development and implementation. PMID:20959322

  20. Co-Evolution of User and Organizational Interfaces: A Longitudinal Case Study of WWW Dissemination of National Statistics.

    ERIC Educational Resources Information Center

    Marchionini, Gary

    2002-01-01

    Describes how user interfaces for the Bureau of Labor Statistics (BLS) web site evolved over a 5-year period along with the larger organizational interface and how this co-evolution has influenced the institution. Interviews with BLS staff and transaction log analysis are the foci of this study, as well as user information-seeking studies and user…

  1. Studies in RF Power Communication, SAR, and Temperature Elevation in Wireless Implantable Neural Interfaces

    PubMed Central

    Zhao, Yujuan; Tang, Lin; Rennaker, Robert; Hutchens, Chris; Ibrahim, Tamer S.

    2013-01-01

    Implantable neural interfaces are designed to provide a high spatial and temporal precision control signal implementing high degree of freedom real-time prosthetic systems. The development of a Radio Frequency (RF) wireless neural interface has the potential to expand the number of applications as well as extend the robustness and longevity compared to wired neural interfaces. However, it is well known that RF signal is absorbed by the body and can result in tissue heating. In this work, numerical studies with analytical validations are performed to provide an assessment of power, heating and specific absorption rate (SAR) associated with the wireless RF transmitting within the human head. The receiving antenna on the neural interface is designed with different geometries and modeled at a range of implanted depths within the brain in order to estimate the maximum receiving power without violating SAR and tissue temperature elevation safety regulations. Based on the size of the designed antenna, sets of frequencies between 1 GHz to 4 GHz have been investigated. As expected the simulations demonstrate that longer receiving antennas (dipole) and lower working frequencies result in greater power availability prior to violating SAR regulations. For a 15 mm dipole antenna operating at 1.24 GHz on the surface of the brain, 730 uW of power could be harvested at the Federal Communications Commission (FCC) SAR violation limit. At approximately 5 cm inside the head, this same antenna would receive 190 uW of power prior to violating SAR regulations. Finally, the 3-D bio-heat simulation results show that for all evaluated antennas and frequency combinations we reach FCC SAR limits well before 1 °C. It is clear that powering neural interfaces via RF is possible, but ultra-low power circuit designs combined with advanced simulation will be required to develop a functional antenna that meets all system requirements. PMID:24223123

  2. Interactions of anesthetics with the water-hexane interface. A molecular dynamics study

    NASA Technical Reports Server (NTRS)

    Chipot, C.; Wilson, M. A.; Pohorille, A.

    1997-01-01

    The free energy profiles characterizing the transfer of nine solutes across the liquid-vapor interfaces of water and hexane and across the water-hexane interface were calculated from molecular dynamics simulations. Among the solutes were n-butane and three of its halogenated derivatives, as well as three halogenated cyclobutanes. The two remaining molecules, dichlorodifluoromethane and 1,2-dichloroperfluoroethane, belong to series of halo-substituted methanes and ethanes, described in previous studies (J. Chem. Phys. 1996, 104, 3760; Chem. Phys. 1996, 204, 337). Each series of molecules contains structurally similar compounds that differ greatly in anesthetic potency. The accuracy of the simulations was tested by comparing the calculated and the experimental free energies of solvation of all nine compounds in water and in hexane. In addition. the calculated and the measured surface excess concentrations of n-butane at the water liquid-vapor interface were compared. In all cases, good agreement with experimental results was found. At the water-hexane interface, the free energy profiles for polar molecules exhibited significant interfacial minima, whereas the profiles for nonpolar molecules did not. The existence of these minima was interpreted in terms of a balance between the free energy contribution arising from solute-solvent interactions and the work to form a cavity that accommodates the solute. These two contributions change monotonically, but oppositely, across the interface. The interfacial solubilities of the solutes, obtained from the free energy profiles, correlate very well with their anesthetic potencies. This is the case even when the Meyer-Overton hypothesis, which predicts a correlation between anesthetic potency and solubility in oil, fails.

  3. Advanced Transportation System Studies Technical Area 2 (TA-2) Heavy Lift Launch Vehicle Development Contract. Volume 2; Technical Results

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The purpose of the Advanced Transportation System Studies (ATSS) Technical Area 2 (TA-2) Heavy Lift Launch Vehicle Development contract was to provide advanced launch vehicle concept definition and analysis to assist NASA in the identification of future launch vehicle requirements. Contracted analysis activities included vehicle sizing and performance analysis, subsystem concept definition, propulsion subsystem definition (foreign and domestic), ground operations and facilities analysis, and life cycle cost estimation. This document is Volume 2 of the final report for the contract. It provides documentation of selected technical results from various TA-2 analysis activities, including a detailed narrative description of the SSTO concept assessment results, a user's guide for the associated SSTO sizing tools, an SSTO turnaround assessment report, an executive summary of the ground operations assessments performed during the first year of the contract, a configuration-independent vehicle health management system requirements report, a copy of all major TA-2 contract presentations, a copy of the FLO launch vehicle final report, and references to Pratt & Whitney's TA-2 sponsored final reports regarding the identification of Russian main propulsion technologies.

  4. Evaluation of a Novel Conjunctive Exploratory Navigation Interface for Consumer Health Information: A Crowdsourced Comparative Study

    PubMed Central

    Cui, Licong; Carter, Rebecca

    2014-01-01

    Background Numerous consumer health information websites have been developed to provide consumers access to health information. However, lookup search is insufficient for consumers to take full advantage of these rich public information resources. Exploratory search is considered a promising complementary mechanism, but its efficacy has never before been rigorously evaluated for consumer health information retrieval interfaces. Objective This study aims to (1) introduce a novel Conjunctive Exploratory Navigation Interface (CENI) for supporting effective consumer health information retrieval and navigation, and (2) evaluate the effectiveness of CENI through a search-interface comparative evaluation using crowdsourcing with Amazon Mechanical Turk (AMT). Methods We collected over 60,000 consumer health questions from NetWellness, one of the first consumer health websites to provide high-quality health information. We designed and developed a novel conjunctive exploratory navigation interface to explore NetWellness health questions with health topics as dynamic and searchable menus. To investigate the effectiveness of CENI, we developed a second interface with keyword-based search only. A crowdsourcing comparative study was carefully designed to compare three search modes of interest: (A) the topic-navigation-based CENI, (B) the keyword-based lookup interface, and (C) either the most commonly available lookup search interface with Google, or the resident advanced search offered by NetWellness. To compare the effectiveness of the three search modes, 9 search tasks were designed with relevant health questions from NetWellness. Each task included a rating of difficulty level and questions for validating the quality of answers. Ninety anonymous and unique AMT workers were recruited as participants. Results Repeated-measures ANOVA analysis of the data showed the search modes A, B, and C had statistically significant differences among their levels of difficulty (P<.001

  5. XPS Study of SiO2 and the Si/SiO2 Interface

    NASA Technical Reports Server (NTRS)

    Grunthaner, F. J.; Grunthaner, P. J.; Vasquez, R. P.; Lewis, B. F.; Maserjian, J.; Madhukar, A.

    1982-01-01

    X-ray photoelectron spectroscopy (XPS) is analytical technique for understanding electronic structure of atoms close to surface in solids, in preference to bulk structure of material. Study found evidence for core-level chemical shifts arising from changes in local structural environment in amorphous SiO2 and at Si/SiO2 interface. Observed XPS spectra may be understood as sequential convolution of several functions, each with well-defined physical interpretation.

  6. Studies of the analyte-carrier interface in flow injection analysis

    SciTech Connect

    Brown, S.D.

    1992-01-01

    Chemical analysis in flowing solution is popular for automation of classical methods. However, most of the classical methods are not specific enough for direct multicomponent analysis of simple mixtures. This research project has the goals of study of rapid multicomponent analysis of transient species in flowing media, and investigations of chemical reactions at interfaces and of effects of competition on distribution of products from interfacial reaction. This report summarizes work done over the past 4.5 years; support has been terminated.

  7. Advanced space communications architecture study. Volume 2: Technical report

    NASA Technical Reports Server (NTRS)

    Horstein, Michael; Hadinger, Peter J.

    1987-01-01

    The technical feasibility and economic viability of satellite system architectures that are suitable for customer premise service (CPS) communications are investigated. System evaluation is performed at 30/20 GHz (Ka-band); however, the system architectures examined are equally applicable to 14/11 GHz (Ku-band). Emphasis is placed on systems that permit low-cost user terminals. Frequency division multiple access (FDMA) is used on the uplink, with typically 10,000 simultaneous accesses per satellite, each of 64 kbps. Bulk demodulators onboard the satellite, in combination with a baseband multiplexer, convert the many narrowband uplink signals into a small number of wideband data streams for downlink transmission. Single-hop network interconnectivity is accomplished via downlink scanning beams. Each satellite is estimated to weigh 5600 lb and consume 6850W of power; the corresponding payload totals are 1000 lb and 5000 W. Nonrecurring satellite cost is estimated at $110 million, with the first-unit cost at $113 million. In large quantities, the user terminal cost estimate is $25,000. For an assumed traffic profile, the required system revenue has been computed as a function of the internal rate of return (IRR) on invested capital. The equivalent user charge per-minute of 64-kbps channel service has also been determined.

  8. Storable droplet interface lipid bilayers for cell-free ion channel studies.

    PubMed

    Jung, Sung-Ho; Choi, Sangbaek; Kim, Young-Rok; Jeon, Tae-Joon

    2012-01-01

    An artificially created lipid bilayer is an important platform in studying ion channels and engineered biosensor applications. However, a lipid bilayer created using conventional techniques is fragile and short-lived, and the measurement of ion channels requires expertise and laborious procedures, precluding practical applications. Here, we demonstrate a storable droplet lipid bilayer precursor frozen with ion channels, resulting in a droplet interface bilayer upon thawing. A small vial with an aqueous droplet in organic solution was flash frozen in -80 °C methanol immediately after an aqueous droplet was introduced into the organic solution and gravity draws the droplet down to the interface upon thawing. A lipid bilayer created along the interface using this method had giga-ohm resistance and typical specific capacitance values. The noise level of this system is favorably comparable to the conventional system. The subsequent incorporation of ion channels, alpha-hemolysin and gramicidin A, showed typical conductance values consistent with those in previous literatures. This novel system to create a lipid bilayer as a whole can be automated from its manufacture to use and indefinitely stored when frozen. As a result, ion channel measurements can be carried out in any place, increasing the accessibility of ion channel studies as well as a number of applications, such as biosensors, ion channel drug screening, and biophysical studies. PMID:21909672

  9. Fermi-level pinning through defects at GaAs/oxide interfaces: A density functional study

    NASA Astrophysics Data System (ADS)

    Colleoni, Davide; Miceli, Giacomo; Pasquarello, Alfredo

    2015-09-01

    Using density functional calculations, we study a set of candidate defects for Fermi-level pinning at GaAs/oxide interfaces. The set of considered defects comprises both bulklike and interfacial defects, including As antisites, Ga and As dangling bonds, the As-As dimer/dangling bond defect, and several defect complexes. The defects are generated within atomistic model structures representing the GaAs /Al2O3 interface. Formation energies of bulklike defects are obtained and compared with those of corresponding bulk defects, while interfacial defects are studied through their relative defect energies. Finite-size corrections to the defect energies are applied through a scheme that accounts for the interfacial geometry of our models. Defect levels are defined as thermodynamic transition levels between different charge states and are calculated for all considered defects. Through an alignment procedure based on hybrid functional calculations, the defect levels are then positioned within the calculated band gap of GaAs that reproduces the experimental one, thereby enabling direct comparisons with the experimental density of defect states. Our study shows that several As-related defects show a similar amphoteric bistability between an As-As dimer state and a configuration with two doubly occupied As dangling bonds. The associated charge transition levels generally lie in the midgap region, in accord with experimental observations. This mechanism is proposed as the origin of the observed Fermi-level pinning at GaAs/oxide interfaces.

  10. Interaction between dimer interface residues of native and mutated SOD1 protein: a theoretical study.

    PubMed

    Keerthana, S P; Kolandaivel, P

    2015-04-01

    Cu-Zn superoxide dismutase 1 (SOD1) is a highly conserved bimetallic protein enzyme, used for the scavenging the superoxide radicals (O2 (-)) produced due to aerobic metabolism in the mitochondrial respiratory chain. Over 100 mutations have been identified and found to be in the homodimeric structure of SOD1. The enzyme has to be maintained in its dimeric state for the structural stability and enzymatic activity. From our investigation, we found that the mutations apart from the dimer interface residues are found to affect the dimer stability of protein and hence enhancing the aggregation and misfolding tendency of mutated protein. The homodimeric state of SOD1 is found to be held together by the non-covalent interactions. The molecular dynamics simulation has been used to study the hydrogen bond interactions between the dimer interface residues of the monomers in native and mutated forms of SOD1 in apo- and holo-states. The results obtained by this analysis reveal the fact that the loss of hydrogen bond interactions between the monomers of the dimer is responsible for the reduced stability of the apo- and holo-mutant forms of SOD1. The conformers with dimer interface residues in native and mutated protein obtained by the molecular dynamics simulation is subjected to quantum mechanical study using M052X/6-31G(d) level of theory. The charge transfer between N-H···O interactions in the dimer interface residues were studied. The weak interaction between the monomers of the dimer accounts for the reduced dimerization and enhanced deformation energy in the mutated SOD1 protein. PMID:25578810

  11. Advanced transportation system studies, technical area 3. Alternate propulsion subsystem concepts: J-2S restart study

    NASA Astrophysics Data System (ADS)

    Vilja, John; Levack, Daniel

    1993-04-01

    The objectives were to assess what design changes would be required to remit late production of the J-2S engine for use as a large high energy upper stage engine. The study assessed design changes required to perform per the J-2S model specification, manufacturing changes required due to obsolescence or improvements in state-of-the-practice, availability issues for supplier provided items, and provided cost and schedule estimates for this configuration. The confidence that J-2S production could be reinitiated within reasonable costs and schedules was provided. No significant technical issues were identified in either the producibility study or in the review of previous technical data. Areas of potential cost reduction were identified which could be quantified to a greater extent with further manufacturing planning. The proposed schedule can be met with no foreseeable impacts. The results of the study provided the necessary foundation for the detailed manufacturing and test plans and non-recurring and recurring cost estimates that are needed to complete the effort to reinitiate production of the J-2S engine system.

  12. Advanced transportation system studies, technical area 3. Alternate propulsion subsystem concepts: J-2S restart study

    NASA Technical Reports Server (NTRS)

    Vilja, John; Levack, Daniel

    1993-01-01

    The objectives were to assess what design changes would be required to remit late production of the J-2S engine for use as a large high energy upper stage engine. The study assessed design changes required to perform per the J-2S model specification, manufacturing changes required due to obsolescence or improvements in state-of-the-practice, availability issues for supplier provided items, and provided cost and schedule estimates for this configuration. The confidence that J-2S production could be reinitiated within reasonable costs and schedules was provided. No significant technical issues were identified in either the producibility study or in the review of previous technical data. Areas of potential cost reduction were identified which could be quantified to a greater extent with further manufacturing planning. The proposed schedule can be met with no foreseeable impacts. The results of the study provided the necessary foundation for the detailed manufacturing and test plans and non-recurring and recurring cost estimates that are needed to complete the effort to reinitiate production of the J-2S engine system.

  13. Technical Note: Groundwater flow modeling in coastal aquifers - the influence of submarine groundwater discharge on the position of the saltwater-freshwater interface

    NASA Astrophysics Data System (ADS)

    Shishaye, H. A.

    2015-04-01

    An investigation of the impact of submarine groundwater discharge on the position of saltwater-freshwater interface is presented in this manuscript. Two conceptualizations were considered and analyzed using both analytic and numerical techniques, for comparison purposes. The first conceptualization assumes that the tip of the saltwater-freshwater interface occurs at the shoreline, and the second conceptualization allows for the tip to extend off-shore. Analytic solutions exist for both conceptualizations, i.e., Strack (1976) for conceptualization 1 and Bakker (2006) for conceptualization 2. Results from both analytic and numeric analysis for the two conceptualizations are presented. Results from the first conceptualization were found to overestimate the inland distance to the interface toe, compared to the second conceptualization, for it ignores the influence of submarine groundwater discharge on the interface location. Moreover, results from the analytic solutions as a whole were found to overestimate the interface location compared to the numerical modeling results, for analytic solutions are based on the sharp interface approximations. Therefore, an empirically derived dispersion factor should be used to correct the analytic solution results so as to compare them with the numerically simulated values. Furthermore, offshore model extents should be incorporated when modeling coastal aquifer systems to include the influence of submarine groundwater discharge on the saltwater-freshwater interface position.

  14. Cr/B4C multilayer mirrors: Study of interfaces and X-ray reflectance

    DOE PAGESBeta

    Burcklen, C.; Soufli, R.; Gullikson, E.; Meltchakov, E.; Dennetiere, D.; Polack, F.; Capitanio, B.; Thomasset, M.; Jerome, A.; de Rossi, S.; et al

    2016-03-24

    Here, we present an experimental study of the effect of layer interfaces on the x-ray reflectance in Cr/B4C multilayer interference coatings with layer thicknesses ranging from 0.7 nm to 5.4 nm. The multilayers were deposited by magnetron sputtering and by ion beam sputtering. Grazing incidence x-ray reflectometry, soft x-ray reflectometry, and transmission electron microscopy reveal asymmetric multilayer structures with a larger B4C-on-Cr interface, which we modeled with a 1–1.5 nm thick interfacial layer. Reflectance measurements in the vicinity of the Cr L2,3 absorption edge demonstrate fine structure that is not predicted by simulations using the currently tabulated refractive index (opticalmore » constants) values for Cr.« less

  15. The Pt(111)/electrolyte interface under oxygen reduction reaction conditions: an electrochemical impedance spectroscopy study.

    PubMed

    Bondarenko, Alexander S; Stephens, Ifan E L; Hansen, Heine A; Pérez-Alonso, Francisco J; Tripkovic, Vladimir; Johansson, Tobias P; Rossmeisl, Jan; Nørskov, Jens K; Chorkendorff, Ib

    2011-03-01

    The Pt(111)/electrolyte interface has been characterized during the oxygen reduction reaction (ORR) in 0.1 M HClO(4) using electrochemical impedance spectroscopy. The surface was studied within the potential region where adsorption of OH* and O* species occur without significant place exchange between the adsorbate and Pt surface atoms (0.45-1.15 V vs RHE). An equivalent electric circuit is proposed to model the Pt(111)/electrolyte interface under ORR conditions within the selected potential window. This equivalent circuit reflects three processes with different time constants, which occur simultaneously during the ORR at Pt(111). Density functional theory (DFT) calculations were used to correlate and interpret the results of the measurements. The calculations indicate that the coadsorption of ClO(4)* and Cl* with OH* is unlikely. Our analysis suggests that the two-dimensional (2D) structures formed in O(2)-free solution are also formed under ORR conditions. PMID:21244087

  16. A comparative study of the thermal interface materials with graphene and boron nitride fillers

    NASA Astrophysics Data System (ADS)

    Kargar, F.; Salgado, R.; Legedza, S.; Renteria, J.; Balandin, A. A.

    2014-09-01

    We report the results of an experimental study that compares the performance of graphene and boron nitride flakes as fillers in the thermal interface materials. The thickness of both fillers varied from a single atomic plane to about a hundred. The measurements have been conducted using a standard TIM tester. Our results show that the addition of a small fraction of graphene (f=4 wt%) to a commercial thermal interface material increases the resulting apparent thermal conductivity substantially stronger than the addition of boron nitride. The obtained data suggest that graphene and fewlayer graphene flakes couple better to the matrix materials than the boron nitride fillers. A combination of both fillers can be used to increase the thermal conductivity while controlling the electrical conduction.

  17. X-ray absorption studies of Ti/polymer and Cr/polymer interfaces

    SciTech Connect

    Opila, R.L.; Konstadinidis, K.; Ibidunni, A.O; Davenport, A.J.; Isaacs, H.S.

    1993-11-01

    The interface formed between metals, Ti and Cr, and polymers, epoxy, and triazine, have been studied, non-destructively, using x-ray absorption spectroscopy. The metals were sputtered onto the polymer surfaces. Titanium reacts extensively, up to Ti thickness of 100 {Angstrom} while Cr remains primarily metallic. In situ heating at 200{degree}C increases the extent of reaction for both metals. Heating has a greater effect on metal/epoxy interfaces than metal/triazine. Titanium and Cr were ion implanted into the polymer in order to determine the interactions of isolated metal atoms with the polymer. Titanium and Cr appear to form oxides as the final reaction product, and the Ti is tetrahedrally coordinated.

  18. First-principles study of the Fe | MgO(0 0 1) interface: magnetic anisotropy.

    PubMed

    Bose, Thomas; Cuadrado, Ramon; Evans, Richard F L; Chepulskii, Roman V; Apalkov, Dmytro; Chantrell, Roy W

    2016-04-20

    We present a systematic first-principles study of Fe | MgO bilayer systems emphasizing the influence of the iron layer thickness on the geometry, the electronic structure and the magnetic properties. Our calculations ensure the unconstrained structural relaxation at scalar relativistic level for various numbers of iron layers placed on the magnesium oxide substrate. Our results show that due to the formation of the interface the electronic structure of the interface iron atoms is significantly modified involving charge transfer within the iron subsystem. In addition, we find that the magnetic anisotropy energy increases from 1.9 mJ m(-2) for 3 Fe layers up to 3.0 mJ m(-2) for 11 Fe layers. PMID:26987845

  19. Cr/B4C multilayer mirrors: Study of interfaces and X-ray reflectance

    NASA Astrophysics Data System (ADS)

    Burcklen, C.; Soufli, R.; Dennetiere, D.; Polack, F.; Capitanio, B.; Gullikson, E.; Meltchakov, E.; Thomasset, M.; Jérome, A.; de Rossi, S.; Delmotte, F.

    2016-03-01

    We present an experimental study of the effect of layer interfaces on the x-ray reflectance in Cr/B4C multilayer interference coatings with layer thicknesses ranging from 0.7 nm to 5.4 nm. The multilayers were deposited by magnetron sputtering and by ion beam sputtering. Grazing incidence x-ray reflectometry, soft x-ray reflectometry, and transmission electron microscopy reveal asymmetric multilayer structures with a larger B4C-on-Cr interface, which we modeled with a 1-1.5 nm thick interfacial layer. Reflectance measurements in the vicinity of the Cr L2,3 absorption edge demonstrate fine structure that is not predicted by simulations using the currently tabulated refractive index (optical constants) values for Cr.

  20. Application of Neutron Reflectivity for Studies of Biomolecular Structures and Functions at Interfaces

    SciTech Connect

    Johs, Alexander; Liang, Liyuan; Gu, Baohua; Ankner, John Francis; Wang, Wei

    2009-01-01

    Structures and functions of cell membranes are of central importance in understanding processes such as cell signaling, chemotaxis, redox transformation, biofilm formation, and mineralization occurring at interfaces. This chapter provides an overview of the application of neutron reflectivity (NR) as a unique tool for probing biomolecular structures and mechanisms as a first step toward understanding protein protein, protein lipid, and protein mineral interactions at the membrane substrate interfaces. Emphasis is given to the review of existing literature on the assembly of biomimetic membrane systems, such as supported membranes for NR studies, and demonstration of model calculations showing the potential of NR to elucidate molecular fundamentals of microbial cell mineral interactions and structure functional relationships of electron transport pathways. The increased neutron flux afforded by current and upcoming neutron sources holds promise for elucidating detailed processes such as phase separation, formation of microdomains, and membrane interactions with proteins and peptides in biological systems.

  1. Theoretical Study of Excess Si Emitted from Si-oxide/Si Interfaces

    NASA Astrophysics Data System (ADS)

    Kageshima, Hiroyuki; Uematsu, Masahi; Akagi, Kazuto; Tsuneyuki, Shinji; Akiyama, Toru; Shiraishi, Kenji

    2004-12-01

    The excess Si emitted from the Si-oxide/Si interface is studied using the first-principles calculations. It is shown that the excess Si can have many (meta-) stable positions around the interface. In addition, some positions in the oxide do not have any dangling bonds or floating bonds in contrast to those in the bulk crystalline Si. The results indicate that the emitted Si can be located in the oxide layer but they do not necessarily cause charge traps in the oxide. The emitted Si atoms are thought to just be oxidized and absorbed into the oxide while a portion of them cause the E' centers, the Pb centers or charge traps.

  2. Molecular dynamics study of two-dimensional sum frequency generation spectra at vapor/water interface

    SciTech Connect

    Ishiyama, Tatsuya; Morita, Akihiro; Tahara, Tahei

    2015-06-07

    Two-dimensional heterodyne-detected vibrational sum frequency generation (2D HD-VSFG) spectra at vapor/water interface were studied by molecular dynamics (MD) simulation with a classical flexible and nonpolarizable model. The present model well describes the spectral diffusion of 2D infrared spectrum of bulk water as well as 2D HD-VSFG at the interface. The effect of isotopic dilution on the 2D HD-VSFG was elucidated by comparing the normal (H{sub 2}O) water and HOD water. We further performed decomposition analysis of 2D HD-VSFG into the hydrogen-bonding and the dangling (or free) OH vibrations, and thereby disentangled the different spectral responses and spectral diffusion in the 2D HD-VSFG. The present MD simulation demonstrated the role of anharmonic coupling between these modes on the cross peak in the 2D HD-VSFG spectrum.

  3. Ti/CeOx(111) interfaces studied by XPS and STM

    NASA Astrophysics Data System (ADS)

    Zhou, Yinghui; Zhou, Jing

    2012-04-01

    Low coverage of Ti was deposited on the well-ordered CeOx(111) (1.5 < x < 2) thin films grown on Ru(0001) by physical vapor deposition at room temperature. The structure and interaction of Ti/ceria interfaces were investigated with X-ray photoelectron spectroscopy (XPS), low energy electron diffraction (LEED) and scanning tunneling microscopy (STM) techniques under ultrahigh vacuum conditions. XPS data indicate that the deposition of Ti on both oxidized and reduced ceria surfaces causes the partial reduction of Ce from + 4 to + 3 state. Ti is formally in the + 4 state. STM data show the formation of small atomic-like titania features at 300 K, which coalesce to form chain structures upon heating. It is demonstrated in the study that the deposition of Ti can form mixed metal oxides at the interface and modify both electronic and structural properties of the ceria support. The structural study of Ti/ceria interfaces can be a key for understanding the higher catalytic activity of the Ti-CeOx mixed oxide catalysts as compared with the individual pure oxides.

  4. Studies of ferroelectric heterostructure thin films and interfaces via in situ analytical techniques.

    SciTech Connect

    Auciello, O.; Dhote, A.; Gao, Y.; Gruen, D. M.; Im, J.; Irene, E. A.; Krauss, A. R.; Mueller, A. H.; Ramesh, R.

    1999-08-30

    The science and technology of ferroelectric thin films has experienced an explosive development during the last ten years. Low-density non-volatile ferroelectric random access memories (NVFRAMs) are now incorporated in commercial products such as ''smart cards'', while high permittivity capacitors are incorporated in cellular phones. However, substantial work is still needed to develop materials integration strategies for high-density memories. We have demonstrated that the implementation of complementary in situ characterization techniques is critical to understand film growth and interface processes, which play critical roles in film microstructure and properties. We are using uniquely integrated time of flight ion scattering and recoil spectroscopy (TOF-ISARS) and spectroscopic ellipsometry (SE) techniques to perform in situ, real-time studies of film growth processes in the high background gas pressure required to growth ferroelectric thin films. TOF-ISARS provides information on surface processes, while SE permits the investigation of buried interfaces as they are being formed. Recent studies on SrBi{sub 2}Ta{sub 2}O{sub 9} (SBT) and Ba{sub x}Sr{sub 1{minus}x}TiO{sub 3} (BST) film growth and interface processes are discussed.

  5. Single-crystal-silicon-based microinstrument to study friction and wear at MEMS sidewall interfaces

    NASA Astrophysics Data System (ADS)

    Ansari, N.; Ashurst, W. R.

    2012-02-01

    Since the advent of microelectromechanical systems (MEMS) technology, friction and wear are considered as key factors that determine the lifetime and reliability of MEMS devices that contain contacting interfaces. However, to date, our knowledge of the mechanisms that govern friction and wear in MEMS is insufficient. Therefore, systematically investigating friction and wear at MEMS scale is critical for the commercial success of many potential MEMS devices. Specifically, since many emerging MEMS devices contain more sidewall interfaces, which are topographically and chemically different from in-plane interfaces, studying the friction and wear characteristics of MEMS sidewall surfaces is important. The microinstruments that have been used to date to investigate the friction and wear characteristics of MEMS sidewall surfaces possess several limitations induced either by their design or the structural film used to fabricate them. Therefore, in this paper, we report on a single-crystal-silicon-based microinstrument to study the frictional and wear behavior of MEMS sidewalls, which not only addresses some of the limitations of other microinstruments but is also easy to fabricate. The design, modeling and fabrication of the microinstrument are described in this paper. Additionally, the coefficients of static and dynamic friction of octadecyltrichlorosilane-coated sidewall surfaces as well as sidewall surfaces with only native oxide on them are also reported in this paper.

  6. A Comparison Study of Conjunctiva Disorders in Technical and Administrative Sawmill Workers in Nigeria

    PubMed Central

    Njinaka, Itiyafa; Uhumwangho, Odarosa M; Edema, Omolabake T; Dawodu, Oseluese A; Omoti, Afekhide E

    2011-01-01

    Background: Workers in the sawmilling industry are at risk of various ocular hazards as a direct result of the sawmilling processes. The aim of this study was to determine the pattern of conjunctival disorders between technical and administrative sawmill workers in Benin, Nigeria. Methods: A cross-sectional study was performed on sawmill workers in Benin, Nigeria, between January and May 2009, with the aid of pre-tested questionnaires. Ocular examination was performed on all subjects. Data obtained were recorded and analysed using SPSS version 13. Results: A total of 553 sawmill workers were studied, among whom 449 (81.2%) and 104 (18.8%) were technical and administrative workers, respectively. There were 496 (89.7%) males and 57 (10.3%) females. The age range was 15–80 years, with a mean of 38.9 years (SD 12.8). Pingueculum was found in 127 (23%) workers, among whom 122 (27.2%) were technical workers and 5 (4.8%) were administrative workers. Pterygium was present in 65 (11.8%) workers, among whom 64 (14.3%) were technical workers and 1 (1%) was an administrative worker. Seven (1.6%) technical workers used protective eyewear; 2 (0.4%) wore this protective eyewear regularly. Conclusion: Technical sawmill workers are at risk of developing conjunctival disorders, which result from chronic ocular irritation. This can be prevented by the provision of protective eye devices in the workplace. PMID:22135600

  7. Theoretical study of binding and permeation of ether-based polymers through interfaces.

    PubMed

    Samanta, Susruta; Hezaveh, Samira; Roccatano, Danilo

    2013-11-27

    We present a molecular dynamics simulation study on the interactions of poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), and their ABA-type block copolymer, poloxamers, at water/n-heptane and 1,2-dimyristoyl-sn-glycero-3-phospatidycholine (DMPC) lipid bilayer/water interfaces. The partition coefficients in water/1-octanol of the linear polyethers up to three monomers were calculated. The partition coefficients evidenced a higher hydrophobicity of the PPO in comparison to PEO. At the water/n-heptane interface, the polymers tend to adopt elongated conformations in agreement with similar experimental ellipsometry studies of different poloxamers. In the case of the poloxamers at the n-heptane/water interface, the stronger preference of the PPO block for the hydrophobic phase resulted in bottle-brush-type polymer conformations. At lipid bilayer/water interface, the PEO polymers, as expected from their hydrophilic nature, are weakly adsorbed on the surface of the lipid bilayer and locate in the water phase close to the headgroups. The free energy barriers of permeation calculated for short polymer chains suggest a thermodynamics propensity for the water phase that increase with the chain length. The lower affinity of PEO for the hydrophobic interior of the lipid bilayer resulted in the spontaneous expulsion within the simulation time. On the contrary, PPO chains and poloxamers have a longer residence time inside the bilayer, and they tend to concentrate in the tail region of the bilayer near the polar headgroups. In addition, polymers with PPO unit length comparable to the thickness of the hydrophobic region of the bilayer tend to span across the bilayer. PMID:24219592

  8. Training of Teachers/Trainers in Technical and Vocational Education. UNEVOC Studies in Technical and Vocational Education, Number 11.

    ERIC Educational Resources Information Center

    United Nations Economic, Scientific, and Cultural Organization, Paris (France). Section for Technical and Vocational Education.

    This document contains nine papers about and from an international roundtable on the training of teachers in technical and vocational education. The first paper, a Final Report of the "International Round Table on Training of Teachers in Technical and Vocational Education (Curitiba, Brazil, 7-10 April 1997)," examines the following: sociopolitical…

  9. Synchrotron-radiation photoemission study of the ultrathin Ba/3C-SiC(111) interface

    NASA Astrophysics Data System (ADS)

    Kukushkin, S. A.; Benemanskaya, G. V.; Dementev, P. A.; Timoshnev, S. N.; Senkovskiy, B.

    2016-03-01

    Electronic structure of the Ba/3C-SiC(111) interface has been detailed studied in situ in an ultrahigh vacuum using synchrotron radiation photoemission spectroscopy with photon energies in the range of 100-450 eV. The 3C-SiC(111) samples were grown by a new method of epitaxy of low-defect unstressed nanoscaled silicon carbide films on silicon substrates. Valence band photoemission and both the Si 2p, C 1s core level spectra have been investigated as a function of Ba submonolayer coverage. Under Ba adsorption two induced surface bands are found at binding energies of 2 eV and 6 eV. It is obtained that Ba/3C-SiC(111) interface can be characterized as metallic-like. Modification of both the Si 2p and C 1s surface-related components were ascertained and shown to be provided by redistribution effect of electron density between Ba adatoms and both the Si surface and C interface atoms.

  10. First-Principles Study of Enhanced Magnetoelectric Effects at the Fe/MgO(001) Interface

    NASA Astrophysics Data System (ADS)

    Niranjan, M. K.; Jaswal, S. S.; Tsymbal, E. Y.; Duan, C.-G.

    2010-03-01

    The magnetoelectric effect allows affecting magnetic properties of materials by electric fields with potential for technological applications such as electrically controlled magnetic data storage. In this study we explore, using first-principles methods, the magnetoelectric effect at the Fe/MgO(001) interface^,1. By explicitly introducing an electric field in our density-functional calculations we demonstrate that the magnetic moment of Fe atoms at the interface changes linearly as a function of the applied electric field with the surface magnetoelectric coefficient being strongly enhanced as compared to that for the clean Fe(001) surface.^1 The effect originates from the increased screening charge associated with a large dielectric constant of MgO. The influence of electric field on relative occupancy of the Fe-3d orbitals leads to significant change in the surface magnetocrystalline anisotropy. These results are compared with the available experimental work.^2 Our results indicate that using high-k dielectrics at the interface with ferromagnetic metals may be very effective in controlling the magnetic properties by electric fields thereby leading to interesting device applications. ^1 C.-G. Duan et al., Phys. Rev. Lett. 101, 137201 (2008). ^2 T. Maruyama et al., Nat. Nanotech., 4, 158 (2009).

  11. A comparative study about electronic structures at rubrene/Ag and Ag/rubrene interfaces

    SciTech Connect

    Sinha, Sumona Mukherjee, M.

    2015-10-15

    The contact between the electrode and the organic semiconductor is one of the most crucial factors in determining the organic device performance. The development and production technology of different organic devices require the understanding of different types of metal/organic semiconducting thin film interfaces. Comparisons about the electronic structures at Rubrene/Ag and Ag/Rubrene interfaces have been studied using photoemission spectroscopy. The Ag on rubrene interfaces is found to show more interesting and complex natures than its counterpart. The vacuum level (VL) was shifted about 0.51 eV from push back effect for deposition of 5 Å rubrene onto Ag film whereas the electronic features of silver was only suppressed and no energy shift was resulted. While the deposition of 5 Å Ag onto rubrene film leads to the diffusion of the Ag atoms, as a cluster with quantum size effect, inside the film. Angle dependent XPS measurement indicates that diffused metal clusters were present at entire probed depth of the film. Moreover these clusters dope the uppermost surface of the rubrene film which consequences a shift of the electronic states of thick organic film towards higher binding energy. The VL was found to shift about 0.31 eV toward higher binding energy whereas the shift was around 0.21 eV for the electronic states of rubrene layer.

  12. XPS study of interface formation of CVD SiO2 on InSb

    NASA Astrophysics Data System (ADS)

    Vasquez, R. P.; Grunthaner, F. J.

    1981-10-01

    The interfacial chemistry of CVD SiO2 films deposited on thin native oxides grown on InSb substrates is examined using X-ray photoemission spectroscopy (XPS) and a relatively benign chemical etching technique for depth profiling. An intensity analysis of XPS spectra is used to derive the compositional structure of the interfaces obtained in the SiO2/native oxide/InSb system. Peak positions in these spectra are used to follow the change in substrate surface potential during the etch sequence, and to establish the chemical nature of the species formed during deposition and subsequent processing. Reaction of the substrate with oxygen resulted in an In-rich native oxide and 1-2 monolayers of excess elemental Sb at the native-oxide/substrate interface, incompletely oxidized silane reduced the native oxide, leaving less than 1 monolayer of elemental In at the SiO2/native oxide interface. Etch removal of this thin In-rich layer leads to a change in the substrate surface potential of 0.06 eV, corresponding to a net increase in positive charge. The results are consistent with simple thermodynamic considerations; they are also compared to previously reported studies of deposited dielectrics on III-V compound semiconductors.

  13. Spectroscopic studies of U(VI) sorption at the kaolinite-water interface. Final report

    SciTech Connect

    Thompson, H.A.; Parks, G.A.; Brown, G.E. Jr.

    1994-06-01

    Efficient use of U as a resource and safe handling, recycling and disposal of U-containing wastes require an understanding of the factors controlling the fate of U, where fate refers to the destination of U, typically expressed as an environmental medium or a process phase. The sorption process constitutes a change in elemental fate. Partitioning of an element from solution to a solid phase, or sorption, can be divided into three broad categories: adsorption, surface precipitation, and absorption. Extended X-ray absorption fine structure (EXAFS), a type of X-ray absorption spectroscopy (XAS), offers the possibility for distinguishing among different modes of sorption by characterizing the atomic environment of the sorbing element. In this study, the authors use EXAFS to determine the structure of U(VI) sorption complexes at the kaolinite-water interface. In Chapter One, they present an overview of selected aspects of U structural chemistry as a basis for considering the structural environment of U at the solid-water interface. To evaluate the utility of XAS for characterization of the structural environment of U(VI) at the solid-water interface, they have carried out an in-depth analysis of XAS data from U(VI)-containing solid and solution model compounds, which they describe in Chapter Two. In Chapter three, they consider sorption of U by kaolinite as a means of effecting the removal of U from surface collection pond waters on the Rocky Flats Plant site in northern Colorado.

  14. A technical description of enhancements to the front-end user interface for the Worldwide Household Goods Information System for Transportation Modernization (WHIST-MOD)

    SciTech Connect

    Loftis, J.P.; Spears, P.M. ); James, T.L. )

    1990-08-01

    The Directorate of Personal Property of the Military Traffic Management Command (MTMC) asked Oak Ridge National Laboratory (ORNL) to design a decision support system, the Worldwide Household Goods Information System for Transportation Modernization. This decision support system will automate tasks and provide analysis tools for evaluating the Personal Property Program, predicting impacts to the program, and planning modifications to the program to meet the evolving needs of military service members and the transportation industry. The system designed by ORNL consists of three application modules: system dictionary applications, data acquisition and administration applications, and user applications. The user applications module is divided into two phases: the data selection front-end interface and the postprocessing back-end interface. This paper describes the prototyped front-end interface using ORACLE SQL*Forms, part of the ORACLE Relational Database Management System (RDBMS) toolset. The focus of this paper is a discussion of the need for enhancements to the initial design of the interface and the coding techniques used to prototype the enhancements. These enhancements make the front-end interface more flexible and easier to use by giving users options for identifying data to be used by the back-end interface. This report is based on in-depth interviews of MTMC staff, prototype meetings with the users, and the research and design work conducted at ORNL.

  15. Second Information Technology in Education Study: SITES 2006 Technical Report

    ERIC Educational Resources Information Center

    Carstens, Ralph, Ed.; Pelgrum, Willem J., Ed.

    2009-01-01

    The International Association for the Evaluation of Educational Achievement (IEA) has been conducting comparative studies for 50 years. SITES 2006 is the fifth wave of surveys related to information and communication technology (ICT), a wave that IEA started with its Computers in Education Study (two studies with data collection in 1989 and 1992),…

  16. Communication Requirements of Employees of Business and Industry Represented by Areas of Technological Study at Southern Maine Vocational Technical Institute.

    ERIC Educational Resources Information Center

    Cary, Penny J.; Sweeney, Kevin F.

    A study examined the need and demand for communication skills for employees in the technical fields for which Southern Maine Vocational Technical Institute offers programs of academic preparation. Two members of the Institute's English Department interviewed representatives of organizations that have hired technical program graduates. Further…

  17. Combining Academic and Technical Studies to Prepare Students for College and Careers

    ERIC Educational Resources Information Center

    Southern Regional Education Board (SREB), 2009

    2009-01-01

    Students preparing for college and careers need access to career-focused programs of study that combine challenging academic content and intellectually demanding career/technical (CT) studies. Schools wanting to raise student achievement can create career-focused programs of study that connect a solid academic core with a sequence of CT courses.…

  18. An Approach for Applying Cultural Study Theory to Technical Writing Research.

    ERIC Educational Resources Information Center

    Longo, Bernadette

    1998-01-01

    Contrasts ideas of culture in social constructionist and cultural study research designs, addressing how each type of design impacts issues that can be analyzed in research studies. Explores implications for objectivity and validity in speculative cultural study research. Suggests how technical writing can be constituted as an object of study…

  19. Theology Lectures as Lexical Environments: A Case Study of Technical Vocabulary Use

    ERIC Educational Resources Information Center

    Lessard-Clouston, Michael

    2010-01-01

    This article presents a descriptive case study on the use of technical vocabulary in the lectures of a first-year graduate theology course in Canada. It first contextualizes this research by noting four kinds of English vocabulary and the study of classrooms as lexical environments. Next it outlines the study's methodology, including the…

  20. The New Historicism and Studies in the History of Business and Technical Writing.

    ERIC Educational Resources Information Center

    Dillon, W. Tracy

    1997-01-01

    Argues that researchers can benefit as scholars/teachers by conducting studies in the history of business and technical writing within the framework of the new historicism. Discusses problems and features of historical studies literature. Explains the legitimizing effects of treating studies as the new historicism. Advocates teaching students to…

  1. 41 CFR 60-3.14 - Technical standards for validity studies.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... be met in conducting a validity study. Nothing in these guidelines is intended to preclude the... procedures. Where it is not technically feasible for a user to conduct a validity study, the user has the... should be based on review of information about the job. Any validity study should be based upon a...

  2. 41 CFR 60-3.14 - Technical standards for validity studies.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... be met in conducting a validity study. Nothing in these guidelines is intended to preclude the... procedures. Where it is not technically feasible for a user to conduct a validity study, the user has the... should be based on review of information about the job. Any validity study should be based upon a...

  3. 41 CFR 60-3.14 - Technical standards for validity studies.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... be met in conducting a validity study. Nothing in these guidelines is intended to preclude the... procedures. Where it is not technically feasible for a user to conduct a validity study, the user has the... should be based on review of information about the job. Any validity study should be based upon a...

  4. 41 CFR 60-3.14 - Technical standards for validity studies.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... be met in conducting a validity study. Nothing in these guidelines is intended to preclude the... procedures. Where it is not technically feasible for a user to conduct a validity study, the user has the... should be based on review of information about the job. Any validity study should be based upon a...

  5. 41 CFR 60-3.14 - Technical standards for validity studies.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... be met in conducting a validity study. Nothing in these guidelines is intended to preclude the... procedures. Where it is not technically feasible for a user to conduct a validity study, the user has the... should be based on review of information about the job. Any validity study should be based upon a...

  6. Information transfer satellite concept study. Volume 2: Technical

    NASA Technical Reports Server (NTRS)

    Bergin, P.; Kincade, C.; Kurpiewski, D.; Leinhaupel, F.; Millican, F.; Onstad, R.

    1971-01-01

    The ITS concept study is preceded by two requirements studies whose primary objectives are to identify viable demands and to develop the functional requirements associated with these demands. In addition to continuing this basic activity the ITS concept study objectives are to: (1) develop tools and techniques for planning advanced information transfer satellite communications systems, and to (2) select viable systems for further analysis both in their near-term and in the far-term aspects.

  7. Nonlinear vibrational spectroscopic studies of molecular interaction and charging behavior at solid/liquid interfaces

    NASA Astrophysics Data System (ADS)

    Zhang, Luning

    Solid-liquid interfaces have been the focus of different communities of scientists due to its importance in industrial applications and chemical processes in nature. Molecular interactions and surface charges affect the physicochemical properties of these interfaces and a thorough understanding is still lacking now. This thesis describes our work in studying several model solid-liquid interfaces using sum-frequency vibrational spectroscopy. Through the studies of interfacial vibrational spectra, we hope to gain better understanding of molecular interactions in competitive adsorption process and also surface charging behavior at different pH and salt concentrations. We start by studying alcohol-water mixture and the adsorption behavior at both hydrophilic and hydrophobic surfaces. In both cases, alcohol adsorbs preferentially from water. The tendency for water to form strong hydrogen-bonding network is the driving force for preferential adsorption of alcohol. We proposed two different interfacial molecular structures on hydrophilic and hydrophobic surfaces. We move on to study the interaction of pure water with a solid surface. Single crystal alumina is used as a model system. At different pH, the surface can undergo protonation and deprotonation reactions and accumulates surface charge. Both the hydrogen-bonding with water and the surface field created by surface charge can affect interfacial water structure. Combining the information obtained with intensity and phase spectra, we find water molecules have two types of bonding within the interfacial layer: weakly hydrogen-bonded species near 3450 cm-1 that does not flip with switching surface charge, and strongly hydrogen-bonded species at 3200 cm-1 that readily flips with switching surface field. One other system we have studied is nanoporous silica-water interface. We found that signal from interfacial water is reduced due to the porous nature of the film. The water spectral features tell us about the interfacial

  8. Background, Schooling, and Achievement. Sustaining Effects Study Technical Report 20.

    ERIC Educational Resources Information Center

    Won, Eugene Y. T.; And Others

    This report of a study on the influence of education on student achievement finds that while schooling does have some tangible effects, they are not enough to significantly counterbalance the effects of students' social backgrounds. The report is part of an extensive series of studies on compensatory education and its long-term effects. The study…

  9. An evaluation of selected NASA scientific and technical information products: Results of a pilot study

    NASA Technical Reports Server (NTRS)

    Pinelli, Thomas E.; Glassman, Myron

    1989-01-01

    A pilot study was conducted to evaluate selected NASA scientific and technical information (STI) products. The study, which utilized survey research in the form of a self-administered mail questionnaire, had a two-fold purpose -- to gather baseline data regarding the use and perceived usefulness of selected NASA STI products and to develop/validate questions that could be used in a future study concerned with the role of the U.S. government technical report in aeronautics. The sample frame consisted of 25,000 members of the American Institute of Aeronautics and Astronautics in the U.S. with academic, government or industrial affiliation. Simple random sampling was used to select 2000 individuals to participate in the study. Three hundred fifty-three usable questionnaires (17 percent response rate) were received by the established cutoff date. The findings indicate that: (1) NASA STI is used and is generally perceived as being important; (2) the use rate for NASA-authored conference/meeting papers, journal articles, and technical reports is fairly uniform; (3) a considerable number of respondents are unfamiliar with STAR (Scientific and Technical Aerospace Reports), IAA (International Aerospace Abstracts), SCAN (Selected Current Aerospace Notices), and the RECON on-line retrieval system; (4) a considerable number of respondents who are familiar with these media do not use them; and (5) the perceived quality of NASA-authored journal articles and technical reports is very good.

  10. Technical proposal: Groundwater development feasibility study of the Chisumbanje area, Zimbabwe. Export trade information

    SciTech Connect

    Not Available

    1986-02-01

    The document is the second volume of a final report for Phase II of a feasibility study conducted for the Regional Water Authority (RWA) of Zimbabwe. The report documents the second phase of a study to assess the feasibility of developing groundwater for irrigation of the Chisumbanje area. This phase of the study included installation of test boreholes in several locations. The volume encompasses the technical scope of work and addendum. The following subjects are discussed in the volume: geographic setting; concepts for successful location of groundwater; and technical approach to the project. A proposed scope of work, schedule and project liaison are presented.

  11. Eye-voice-controlled interface

    NASA Technical Reports Server (NTRS)

    Glenn, Floyd A., III; Iavecchia, Helene P.; Ross, Lorna V.; Stokes, James M.; Weiland, William J.

    1986-01-01

    The Ocular Attention-Sensing Interface System (OASIS) is an innovative human-computer interface which utilizes eye movement and voice commands to communicate messages between the operator and the system. This report initially describes some technical issues relevant to the development of such an interface. The results of preliminary experiments which evaluate alternative eye processing algorithms and feedback techniques are presented. Candidate interface applications are also discussed.

  12. Molecular interactions at the hexadecane/water interface in the presence of surfactants studied with second harmonic generation

    NASA Astrophysics Data System (ADS)

    Sang, Yajun; Yang, Fangyuan; Chen, Shunli; Xu, Hongbo; Zhang, Si; Yuan, Qunhui; Gan, Wei

    2015-06-01

    It is important to investigate the influence of surfactants on structures and physical/chemical properties of oil/water interfaces. This work reports a second harmonic generation study of the adsorption of malachite green (MG) on the surfaces of oil droplets in a hexadecane/water emulsion in the presence of surfactants including sodium dodecyl sulfate, polyoxyethylene-sorbitan monooleate (Tween80), and cetyltrimethyl ammonium bromide. It is revealed that surfactants with micromolar concentrations notably influence the adsorption of MG at the oil/water interface. Both competition adsorption and charge-charge interactions played very important roles in affecting the adsorption free energy and the surface density of MG at the oil/water interface. The sensitive detection of the changing oil/water interface with the adsorption of surfactants at such low concentrations provides more information for understanding the behavior of these surfactants at the oil/water interface.

  13. Molecular interactions at the hexadecane/water interface in the presence of surfactants studied with second harmonic generation.

    PubMed

    Sang, Yajun; Yang, Fangyuan; Chen, Shunli; Xu, Hongbo; Zhang, Si; Yuan, Qunhui; Gan, Wei

    2015-06-14

    It is important to investigate the influence of surfactants on structures and physical/chemical properties of oil/water interfaces. This work reports a second harmonic generation study of the adsorption of malachite green (MG) on the surfaces of oil droplets in a hexadecane/water emulsion in the presence of surfactants including sodium dodecyl sulfate, polyoxyethylene-sorbitan monooleate (Tween80), and cetyltrimethyl ammonium bromide. It is revealed that surfactants with micromolar concentrations notably influence the adsorption of MG at the oil/water interface. Both competition adsorption and charge-charge interactions played very important roles in affecting the adsorption free energy and the surface density of MG at the oil/water interface. The sensitive detection of the changing oil/water interface with the adsorption of surfactants at such low concentrations provides more information for understanding the behavior of these surfactants at the oil/water interface. PMID:26071724

  14. Atom-probe tomographic study of interfaces of Cu{sub 2}ZnSnS{sub 4} photovoltaic cells

    SciTech Connect

    Tajima, S. Asahi, R.; Itoh, T.; Hasegawa, M.; Ohishi, K.; Isheim, D.; Seidman, D. N.

    2014-09-01

    The heterophase interfaces between the CdS buffer layer and the Cu{sub 2}ZnSnS{sub 4} (CZTS) absorption layers are one of the main factors affecting photovoltaic performance of CZTS cells. We have studied the compositional distributions at heterophase interfaces in CZTS cells using three-dimensional atom-probe tomography. The results demonstrate: (a) diffusion of Cd into the CZTS layer; (b) segregation of Zn at the CdS/CZTS interface; and (c) a change of oxygen and hydrogen concentrations in the CdS layer depending on the heat treatment. Annealing at 573 K after deposition of CdS improves the photovoltaic properties of CZTS cells probably because of the formation of a heterophase epitaxial junction at the CdS/CZTS interface. Conversely, segregation of Zn at the CdS/CZTS interface after annealing at a higher temperature deteriorates the photovoltaic properties.

  15. Study on Orbital Liquid Transport and Interface Behavior in Vane Tank

    NASA Astrophysics Data System (ADS)

    Kang, Qi; Rui, Wei

    2016-07-01

    Liquid propellant tank is used to supply gas free liquid for spacecraft as an important part of propulsion system. The liquid behavior dominated by surface tension in microgravity is obviously different with that on the ground, which put forward a new challenge to the liquid transport and relocation. The experiments which are investigated at drop tower in National Microgravity Lab have concentrated on liquid relocation following thruster firing. Considered that the liquid located at the bottom in the direction of the acceleration vector, a sphere scale vane tank is used to study the liquid-gas interface behaviors with different acceleration vector and different filling independently and we obtain a series of stable equilibrium interface and relocation time. We find that there is an obvious sedimentation in the direction of acceleration vector when fill rate greater than 2% fill. Suggestions have been put forward that outer vanes transferring liquid to the outlet should be fixed and small holes should be dogged at the vane close to the center post to improve the liquid flow between different vanes when B0 is greater than 2.5. The research about liquid transport alone ribbon vanes is simulated though software Flow3D. The simulation process is verified by comparing the liquid lip and vapor-liquid interface obtained from drop tower experiment and simulation result when fill rate is 15%. Then the influence of fill rate, numbers of vanes and the gap between vane and wall is studied through the same simulate process. Vanes' configurations are also changed to study the effect on the lip and liquid volume below some section. Some suggestions are put forward for the design of vanes.

  16. First-principles study of point defects at a semicoherent interface

    PubMed Central

    Metsanurk, E.; Tamm, A.; Caro, A.; Aabloo, A.; Klintenberg, M.

    2014-01-01

    Most of the atomistic modeling of semicoherent metal-metal interfaces has so far been based on the use of semiempirical interatomic potentials. We show that key conclusions drawn from previous studies are in contradiction with more precise ab-initio calculations. In particular we find that single point defects do not delocalize, but remain compact near the interfacial plane in Cu-Nb multilayers. We give a simple qualitative explanation for this difference on the basis of the well known limited transferability of empirical potentials. PMID:25524061

  17. Dual-probe scanning tunneling microscope for study of nanoscale metal-semiconductor interfaces

    NASA Astrophysics Data System (ADS)

    Yi, W.; Kaya, I. I.; Altfeder, I. B.; Appelbaum, I.; Chen, D. M.; Narayanamurti, V.

    2005-06-01

    Using a dual-probe scanning tunneling microscope, we have performed three-terminal ballistic electron emission spectroscopy on Au /GaAs(100) by contacting the patterned metallic thin film with one tip and injecting ballistic electrons with another tip. The collector current spectra agree with a Monte-Carlo simulation based on modified planar tunneling theory. Our results suggest that it is possible to study nanoscale metal-semiconductor interfaces without the requirement of an externally-contacted continuous metal thin film.

  18. Ion Scattering Studies of Silicon Surfaces and Interfaces: Structure and Neutralization.

    NASA Astrophysics Data System (ADS)

    Haight, Richard Alan

    This thesis chronicles three experiments which represent the major thrust of studies performed during my tenure as a graduate student at the State University of New York at Albany. Chapter 1 introduces the fundamental considerations of the physics of ion scattering and its applications to studies of surfaces, interfaces and ion neutralization. Basic formula are stated and the two atom model using the Coulomb interaction potential is developed as an approximate prediction of the surface peak intensity. The second chapter discusses a study of the neutralization of 75-180 KeV He ions scattered from clean and Cs covered Si (100); an experiment performed at Bell Laboratories. It is shown that ion neutralization occurs at the surface of the solid; the ion retains no memory of its journey within the bulk. It is also observed that the ion fraction exhibits no dependence upon takeoff angle, a result which differs markedly from the exponential angular dependence observed at lower velocities. Changes in the Si scattered ion fraction upon cesiation of the Si surface are correlated with the work function change observed by other workers. A model is proposed, and developed in mathematical detail, which includes resonant transitions to the motionally broadened He n=2 quantum level and is compared with the experimental data. The third chapter discusses an ion scattering study of the interfacial structure of the Si-SiO(,2) interface. It is shown that the oxide is stoichiometric to within (TURN)1 monolayer of the interface. Measurements to determine the magnitude and direction of the Si atomic displacements at the interface were compared with Monte Carlo computer simulations and show small lateral and larger vertical displacements in two layers. A model, consistent with the data, is proposed and the effects of these displacements are related qualitatively with theory. The fourth chapter describes a thin Si (111) crystal transmission channeling experiment. In this experiment, the use

  19. First-principles study of point defects at a semicoherent interface

    DOE PAGESBeta

    Metsanurk, E.; Tamm, A.; Caro, A.; Aabloo, A.; Klintenberg, M.

    2014-12-19

    Most of the atomistic modeling of semicoherent metal-metal interfaces has so far been based on the use of semiempirical interatomic potentials. Here, we show that key conclusions drawn from previous studies are in contradiction with more precise ab-initio calculations. In particular we find that single point defects do not delocalize, but remain compact near the interfacial plane in Cu-Nb multilayers. Lastly, we give a simple qualitative explanation for this difference on the basis of the well known limited transferability of empirical potentials.

  20. Resonant photoemission study of the 4f spectral function of cerium in Ce/Fe(100) interfaces

    SciTech Connect

    Witkowski, N.; Bertran, F.; Gourieux, T.; Kierren, B.; Malterre, D.; Panaccione, G. |

    1997-11-01

    In this paper, we present a resonant photoemission study of the cerium 4f spectral function in Ce/Fe(100) interfaces. By covering cerium ultrathin films with lanthanum, we completely suppress the surface contribution of the spectra. Then we show that the cerium atoms at the interface are in an intermediate valent state, whereas the f{sup 1} configuration is stabilized in the top layer. This method allows us to obtain the genuine 4f spectral function of the interface, and could be extended to a study of Ce-based compounds. {copyright} {ital 1997} {ital The American Physical Society}

  1. Study on crystal-melt interface shape of sapphire crystal growth by the KY method

    NASA Astrophysics Data System (ADS)

    Liu, Weina; Lu, Jijun; Chen, Hongjian; Yan, Wenbo; Min, Chunhua; Lian, Qingqing; Wang, Yunman; Cheng, Peng; Liu, Caichi; Xu, Yongliang

    2015-12-01

    In this article, the influence of the flow field structure and temperature gradient of forefront interface on the shape of crystal-melt interface which may reflect the interface stability were analyzed through the method of numerical simulation by using CGSim software. In order to get a suitable interface shape and grow high-quality sapphire crystal, the heater arrangement should be adjusted during the KY process. The results indicate that the effect of Marangoni convection cannot be neglected at the last stage, the crystal-melt interface is governed by the flow field structure and the temperature gradient in melt at the crystal-melt interface. The phenomenon of shoulder concave appears at the stage of shoulder turning and interface inversion appears at the last stage during the crystal growth is discussed. Adjusting heater arrangement may effectively optimize the shape of crystal-melt interface.

  2. A Study of Ontario Farmers' Use of Selected Technical Publications.

    ERIC Educational Resources Information Center

    Bell, Ian C.; Blackburn, Donald J.

    This study sought to determine the extent to which selected publications of the Ontario Department of Agriculture and Food were received by farmers in the Province on Ontario, Canada. Investigations were made of relationships between various social and demographic characteristics of respondents, and their receipt of these publications. A…

  3. A STUDY OF RECOMMENDATIONS FOR TECHNICAL EDUCATION CURRICULA.

    ERIC Educational Resources Information Center

    ARNOLD, JOSEPH P.

    THE PRIMARY PURPOSE OF THIS STUDY WAS TO HAVE MANAGEMENT PERSONNEL AND TECHNICIANS IDENTIFY CORES OF SUBJECT MATTER RELATED TO TECHNICIAN JOB PERFORMANCE AND TO DIFFERENTIATE BETWEEN THEIR JUDGMENTS. FIFTY-TWO TECHNICIANS AND 116 MANAGEMENT PERSONNEL IN 52 ILLINOIS FIRMS EMPLOYING 200 OR MORE PERSONS PARTICIPATED. A 99-CARD CURRICULUM DECK,…

  4. Quantitative modeling and analysis in environmental studies. Technical report

    SciTech Connect

    Gaver, D.P.

    1994-10-01

    This paper reviews some of the many mathematical modeling and statistical data analysis problems that arise in environmental studies. It makes no claim to be comprehensive nor truly up-to-date. It will appear as a chapter in a book on ecotoxicology to be published by CRC Press, probably in 1995. Workshops leading to the book creation were sponsored by The Conte Foundation.

  5. A Study To Identify Academic Personnel Replacement Needs in SUNY Community Colleges and Technical Colleges.

    ERIC Educational Resources Information Center

    Winter, Gene M.; And Others

    In 1990, a study was conducted of full-time faculty, deans, chairpersons, and academic administrators at the State University of New York (SUNY) community and technical colleges. The purpose of the study was to profile these groups and to identify future academic personnel replacement needs. A survey questionnaire mailed to SUNY's 30 community…

  6. An Evaluation of Selected NASA Scientific and Technical Information Products: Results of a Pilot Study.

    ERIC Educational Resources Information Center

    Pinelli, Thomas E.; Glassman, Myron

    A pilot study was conducted to evaluate selected NASA (National Aeronautics and Space Administration) scientific and technical information (STI) products. The study, which utilized survey research in the form of a self-administered mail questionnaire, had a two-fold purpose--to gather baseline data on the use and perceived usefulness of selected…

  7. The 2005 High School Transcript Study User's Guide and Technical Report. NCES 2009-480

    ERIC Educational Resources Information Center

    Shettle, Carolyn; Cubell, Michele; Hoover, Katylee; Kastberg, David; Legum, Stan; Lyons, Marsha; Perkins, Robert; Rizzo, Lou; Roey, Stephen; Sickles, Diane

    2008-01-01

    This technical report documents the procedures used to collect and summarize data from the 2005 High School Transcript Study (HSTS 2005). The transcript studies serve as a barometer for changes in high school graduates' course-taking patterns; these patterns provide information about the rigor of high school curricula followed across the nation.…

  8. Consumer Rights and Accountability in Postsecondary Vocational-Technical Education: An Exploratory Study.

    ERIC Educational Resources Information Center

    Fitzgerald, Brian; Harmon, Lisa

    Beginning in October 1987, Pelavin Associates conducted an exploratory study of consumer rights and accountability in postsecondary vocational-technical (PVT) programs for the U.S. Department of Education. The study focused on how effectively the governance structure--accreditation and federal and state regulation--ensures that consumer rights are…

  9. Analysis of cementless implants using interface nonlinear friction--experimental and finite element studies.

    PubMed

    Dammak, M; Shirazi-Adl, A; Zukor, D J

    1997-02-01

    Measured interface nonlinear friction properties are used to develop models to study the short-term fixation response of smooth- and porous-surfaced posts, bone screws, and plates fixed with and without posts/screws. Experimental studies are carried out to validate the model predictions and identify the relative role of posts and screws in fixation of a plate on a polyurethane block under symmetric/eccentric axial compression loads. The idealized Coulomb's friction is also used for the sake of comparison. The incorporation of measured nonlinear, rather than the idealized Coulomb, friction is essential to compute realistic results. For plate fixation, the experimental and finite element results show that the screw fixation yields the stiffest response followed by the smooth- and then porous-coated post fixation. For example, under 1000 N eccentric axial compression, the edge of the plate opposite the loaded edge is measured to lift by 1147 +/- 72, 244 +/- 38, or 112 +/- 28 microns, respectively, for the cases with no fixation, with smooth-surfaced posts, or with screws. The corresponding models predict, respectively, values of 1538, 347, or 259 microns and also 556 microns for the plate fixed with porous coated posts. The satisfactory agreement between numerical and experimental results confirms the importance of proper interface modelling for the analysis of posts, screws, and complex fixation systems. This becomes further evident when considering cementless implants in which the bone-implant interface exhibits relatively large displacements as the maximum resistance force is reached. The developed models can be used to investigate the post-operative short-term stability of various cementless implant designs. PMID:9001932

  10. Superconducting gravity gradiometer mission. Volume 2: Study team technical report

    NASA Technical Reports Server (NTRS)

    Morgan, Samuel H. (Editor); Paik, Ho Jung (Editor)

    1988-01-01

    Scientific and engineering studies and developments performed or directed by a Study Team composed of various Federal and University activities involved with the development of a three-axis superconducting gravity gradiometer integrated with a six-axis superconducting accelerometer are examined. This instrument is being developed for a future orbital mission to make precise global gravity measurements. The scientific justification and requirements for such a mission are discussed. This includes geophysics, the primary mission objective, as well as secondary objective, such as navigation and feats of fundamental laws of physics, i.e., a null test of the inverse square law of gravitation and tests of general relativity. The instrument design and status along with mission analysis, engineering assessments, and preliminary spacecraft concepts are discussed. In addition, critical spacecraft systems and required technology advancements are examined. The mission requirements and an engineering assessment of a precursor flight test of the instrument are discussed.

  11. Development of instrumentation for surface, interface and thin film science at the Advanced Photon Source. Final Technical Report for period September 15, 1994 - September 14, 2000

    SciTech Connect

    Bedzyk, Michael J.

    2000-09-01

    The P.I. and his research term successfully used the funds from the DOE Instrumentation grant entitled ''Development of Instrumentation for Surface, Interface and Thin Film Science at the Advanced Photon Source'' to design, build, test, and commission a customized surface science x-ray scattering/spectroscopy chamber. This instrumentation, which is presently in use at an APS x-ray undulator beam line operated by the DuPont-Northwestern-Dow Collaborative Access Team, is used for x-ray measurements of surface, interface, thin film, and nano-structures.

  12. Studies of supported hydrodesulfurization catalysts. Final technical report

    SciTech Connect

    Hercules, D.M.

    1995-10-26

    This report describes a series of studies on the following: Mo/titania and Mo/alumina catalysts for thiophene hydrodesulfurization; absorption of metal oxyanion on alumina; particle size effects for Co/silica catalyst for CO hydrogenation; correlation of Mo oxidation states with benzene hydrogenation activity; factor analysis for curve fitting Mo ESCA spectra; and quantitative Raman and ESCA characterization of W/titania catalysts. 27 refs.

  13. Mechanical properties of the interface structure of nanodiamond composite films: First-principles studies

    NASA Astrophysics Data System (ADS)

    Zhang, Suhui; Liu, Xuejie; Jiang, Yongjun; Ren, Yuan; Li, Suozhi

    2016-02-01

    The elastic properties of the interface structure of nanodiamond composite films are investigated using first-principles calculations. The nanodiamond grains in the films are surrounded by a monolayer heterogeneous interface. The interface phase comprises B, Si, P, and Ge. The elastic constants, bulk, shear and Young's modulus of the interface structures are all obtained with first principle calculations. Calculated elastic constants of the diamond (0 0 1) interface are larger than those of the (1 1 1) interface. For the B, Si, P, and Ge interface structures, as the average atomic distance increases, the average Young's modulus decrease, which follows the sequence EbarB>EbarSi >EbarP > EbarGe , with corresponding values of 927.05, 843.841, 840.152, and 819.805 GPa. The ductility and plasticity, as well as the anisotropy values (A and AU) of the interface structures were discussed based on the obtained mechanical parameters. The results show that P interface structures demonstrate ductile property when stressed longitudinally, whereas the other interface structures are all brittle. Then the visualization of the directional dependence of the Young's modulus are also presented. These reflected an interesting results. For the B, Si, and Ge interface structures, whether they show isotropy or anisotropy depends on the crystal structure, while it depends on the direction of the applied strain for the P interface structures.

  14. Care Networking: A Study of Technical Mediations in a Home Telecare Service

    PubMed Central

    Correa, Gonzalo; Domènech, Miquel

    2013-01-01

    This article examines the processes of technical mediation within familial care networks based on a study of home telecare targeted at older people. Supported by contributions from the actor—network theory as part of the social psychology of science and technology, these processes of technical mediation are analyzed using a qualitative approach. The data were gathered through six focus groups and four in-depth interviews; the participants in the study included users, relatives and formal carers. Thematic analysis techniques encompassing the information were used, revealing the effects on the patterns of caring relationships. The results show the interplay between presence-absence made possible by the devices; the two-way direction of care between the older people and the artifacts; and the process of sustaining care using the technology. We conclude that care should be seen as a socio-technical network where technology plays an active role in sustaining family relationships. PMID:23880730

  15. Photovoltaic applications definition and photovoltaic system definition study in the agricultural sector. Volume 2: Technical results

    NASA Astrophysics Data System (ADS)

    Mengel, R. W.; Nadolski, T. P.; Sparks, D. C.; Young, S. K.; Yingst, A.

    1980-05-01

    This volume describes the technical results of the study of potential photovoltaic (P/V) applications in US agriculture. The results presented address all technical aspects of the program and include a summary of agricultural energy consumption. The objectives of the technical effort reported were to: (1) identify and characterize agricultural energy demands that can effectively use P/V power systems; (2) develop effective P/V system designs for the four most promising applications; (3) determine performance and cost estimates for the designs; and (4) recommend systems for early test and demonstration and critical issues requiring further systems studies. The farms chosen for conceptual design include; (1) poultry layer farm, (2) hog production farm, (3) beef feedlot, and (4) year round vegetable farm.

  16. Hydrogen production by supercritical water gasification of biomass. Phase 1 -- Technical and business feasibility study, technical progress report

    SciTech Connect

    1997-12-01

    The nine-month Phase 1 feasibility study was directed toward the application of supercritical water gasification (SCWG) for the economical production and end use of hydrogen from renewable energy sources such as sewage sludge, pulp waste, agricultural wastes, and ultimately the combustible portion of municipal solid waste. Unique in comparison to other gasifier systems, the properties of supercritical water (SCW) are ideal for processing biowastes with high moisture content or contain toxic or hazardous contaminants. During Phase I, an end-to-end SCWG system was evaluated. A range of process options was initially considered for each of the key subsystems. This was followed by tests of sewage sludge feed preparation, pumping and gasification in the SCW pilot plant facility. Based on the initial process review and successful pilot-scale testing, engineering evaluations were performed that defined a baseline system for the production, storage and end use of hydrogen. The results compare favorably with alternative biomass gasifiers currently being developed. The results were then discussed with regional wastewater treatment facility operators to gain their perspective on the proposed commercial SCWG systems and to help define the potential market. Finally, the technical and business plans were developed based on perceived market needs and the projected capital and operating costs of SCWG units. The result is a three-year plan for further development, culminating in a follow-on demonstration test of a 5 MT/day system at a local wastewater treatment plant.

  17. Space station automation study: satellite servicing. Volume II. Technical report

    SciTech Connect

    Meissinger, H.F.

    1984-12-20

    This study was conducted by TRW over the six month time frame from early June through November 1984. Three major tasks were completed: Servicing Requirements (Satellite and Space Station Elements) and the Role of Automation; Assessment of Automation Technology; and Conceptual Design of Servicing Facilities on the Space Station. It was found that many servicing functions could benefit from automation support; that certain research and development activities on automation technologies for servicing should start as soon as possible; and some advanced automation developments for orbital servicing could be effectively applied to US industrial ground based operations. 42 refs., 49 figs., 20 tabs.

  18. Orbit transfer vehicle engine study. Volume 2: Technical report

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The orbit transfer vehicle (OTV) engine study provided parametric performance, engine programmatic, and cost data on the complete propulsive spectrum that is available for a variety of high energy, space maneuvering missions. Candidate OTV engines from the near term RL 10 (and its derivatives) to advanced high performance expander and staged combustion cycle engines were examined. The RL 10/RL 10 derivative performance, cost and schedule data were updated and provisions defined which would be necessary to accommodate extended low thrust operation. Parametric performance, weight, envelope, and cost data were generated for advanced expander and staged combustion OTV engine concepts. A prepoint design study was conducted to optimize thrust chamber geometry and cooling, engine cycle variations, and controls for an advanced expander engine. Operation at low thrust was defined for the advanced expander engine and the feasibility and design impact of kitting was investigated. An analysis of crew safety and mission reliability was conducted for both the staged combustion and advanced expander OTV engine candidates.

  19. Monte Carlo study of the adsorption and aggregation of alkyltrimethylammonium chloride on the montmorillonite-water interface.

    PubMed

    Klebow, Birthe; Meleshyn, Artur

    2012-09-18

    Organically modified clays exhibit adsorption capacities for cations, anions, and nonpolar organic compounds, which make them valuable for various environmental technical applications. To improve the understanding of the adsorption processes, the molecular-scale characterization of the structures of organic aggregates assembled on the external basal surfaces of clay particles is essential. The focus of this Monte Carlo simulation study was on the effects of the surface coverage and the alkyl chain length n on the structures of alkyltrimethylammonium chloride ((C(n)TMA)Cl) aggregates assembled on the montmorillonite-water interface. We found that the amount of adsorbed C(n)TMA(+) ions is independent of the alkyl chain length and increases with the C(n)TMA(+) surface coverage. The C(n)TMA(+) ions predominantly adsorb as inner-sphere complexes; the fraction of outer-sphere adsorbed ions equals only about 10%. The conformational order of the C(n)TMA(+) alkyl chains substantially decreases with decreasing alkyl chain length. In agreement with previous experiments, the amount of C(n)TMA(+) ions that are aggregated at the mineral surface increases with increasing chain length. The maximum value of 0.66 C(n)TMA(+) adsorption complex per unit cell area of the clay surface considerably exceeds the amount of cations required to compensate the negative charge of the montmorillonite surface. Furthermore, in most of the studied systems, fractions of Na(+) surface cations remain adsorbed on montmorillonite. The resulting interfacial positive charge excess is counterbalanced by coadsorbed chloride ions forming ion pairs with both C(n)TMA(+) and Na(+). PMID:22894657

  20. First principles studies of interface dielectric properties of polymer/metal-oxide nanocomposites

    NASA Astrophysics Data System (ADS)

    Yu, Liping

    This thesis is devoted to studying interface dielectric properties of polymer nanocomposites from first principles. We aim to understand at atomic scale the role of interface effects and the dielectric finite size effects of nanoparticles in determining the effective dielectric properties of polymer nanocomposites. To study surface effects from first principles, we first investigate the two common methods, namely dipole correction and Coulomb cutoff, used to eliminate the artificial effects introduced by using the supercell approximation. We implement Coulomb cutoff technique in a plane-wave-based density functional theory code and compare it with dipole correction for the same system under the same conditions. By comparison, both methods are shown to be equivalent and able to remove the artificial effects of periodic images very accurately. We also find that a combination of these two methods offers an easy way to distinguish the localized bound states of interest from highly delocalized unoccupied states while using a relatively small supercell, and to ascertain the convergence of the results with respect to supercell size. To understand the dielectric properties at the atomic scale, we develop a new nanoscale averaging model to connect the macroscopic quantities to the corresponding microscopic ones. This model allows us to compute the spatially resolved local dielectric permittivity, including the critically important ionic contributions, for interfaces and other complex structures. In this model, a simple way of evaluating real-space decay length of the nonlocal dielectric functions is also proposed. By using the dipole correction and our averaging model in supercells, we calculate the optical and static local dielectric permittivity profiles for polymer (polypropylene)/metal-oxide (PbTiO3 and alumina) nanocomposites. Our ab-initio results show that metal-oxide/polymer interface effects are very localized and are mostly confined to the metal-oxide surface side

  1. A first-principles study on interaction of Mg/Ni interface and its hydrogen absorption characteristics

    NASA Astrophysics Data System (ADS)

    Chen, Yuying; Dai, Jianhong; Xie, Ruiwen; Song, Yan

    2016-07-01

    We have investigated the interaction of Mg/Ni interface and its hydrogen adsorption characteristics using first-principles calculations to obtain a better understanding of the Mg/Ni interface as a hydrogen storage material. The smallest work of adhesion of Mg/Ni interface is 4.28 J/m2 with AB stacking sequence in the studied systems. Hydrogen adsorption energy and electronic structures were evaluated to study the interaction characteristics between hydrogen and Mg/Ni interface. The hydrogen adsorption is energetically favored on all considered sites. The hydrogen atom prefers to adsorb on the tetrahedral site of the Ni side of the interface owning the lowest adsorption energy. The plane-averaged charge density and the density of states analysis indicate that the absorption of hydrogen could stabilize the Mg/Ni interface owing to the strongly bonding interactions between hydrogen atom and the host Mg and Ni atoms. Therefore, Mg/Ni interface provides a promising medium for hydrogen storage.

  2. New York Bight Study. Report 1. Hydrodynamic modeling. Technical report

    SciTech Connect

    Scheffner, N.W.; Vemulakonda, S.R.; Mark, D.J.; Butler, H.L.; Kim, K.W.

    1994-08-01

    As a part of the New York (NY) Bight Feasibility Study, a three-dimensional hydrodynamic model of the NY Bight was developed and applied by the Coastal Engineering R h Center of the U.S. Army Engineer Waterways Experiment Station. The study used the three-dimensional hydrodynamic model CH3D-WES for this purpose. A 76 x 45 cell boundary-fitted curvilinear grid was employed in the horizontal and five to ten sigma layers were used in the vertical. Steady-state and diagnostic tests were initially performed, using M, and mixed tides, cross-shelf gradients, winds, and freshwater flows in the Hudson River. All of the tests were successful in reproducing known circulation patterns of the NY Bight system. The model was next successfully calibrated and verified against prototype tidal elevations and currents measured during April and May 1976. As a demonstration of the feasibility of long-term modeling, the hydrodynamics, including salinity and temperature, were simulated for the period April-October 1976. Model results compared favorably with available prototype temperature measurements. Model output was furnished to a water quality model of the NY Bight, which successfully reproduced the hypoxic event of 1976. Model results also were used successfully to run particle tracking and oil spill models of the NY Bight. Finally, the model was demonstrated for the Long Island Sound and East River areas, for the period of May-July 1990. Computed results for elevation, velocity, salinity, and temperature in the Sound as well as net flux in the East River matched measurements reasonably.

  3. MHD modeling of atlas experiments to study transverse shear interface interactions

    SciTech Connect

    Cochran, F. L.; Hammerberg, J. E.; Keinigs, R. K.; Faehl, R. J.

    2001-01-01

    The transverse shear established at the interface of two solids moving at differential velocities on the order of the sound speed is being studied in experiments on the ATLAS capacitor bank at Los Alamos. The ATLAS bank has finished certification tests and has demonstrated peak currents of 27.5 MA into an inductive load with a risetime of 5 microseconds. One- and two-dimensional MHD calculations have been performed in support of these 'friction-like' ATLAS experiments. Current flowing along the outer surface of a thick aluminum liner, 10 mm thick at impact with the interaction target, accelerates the liner to velocities of {approx}1.0-1.5 km/s. This cylindrically imploding liner impacts a target assembly composed of alternating disks of high- and low-density materials. Different shock speeds in the two materials leads to a differential velocity along the interface. Shock heating, elastic-plastic flow, and stress transport are included in the calculations. Material strength properties are modeled with a Steinburg-Guinan treatment in these first studies. Various design configurations for the ATLAS experiments are now being considered and will be presented.

  4. Tunneling of electrons via rotor-stator molecular interfaces: Combined ab initio and model study

    NASA Astrophysics Data System (ADS)

    Petreska, Irina; Ohanesjan, Vladimir; Pejov, Ljupčo; Kocarev, Ljupčo

    2016-07-01

    Tunneling of electrons through rotor-stator anthracene aldehyde molecular interfaces is studied with a combined ab initio and model approach. Molecular electronic structure calculated from first principles is utilized to model different shapes of tunneling barriers. Together with a rectangular barrier, we also consider a sinusoidal shape that captures the effects of the molecular internal structure more realistically. Quasiclassical approach with the Simmons' formula for current density is implemented. Special attention is paid on conformational dependence of the tunneling current. Our results confirm that the presence of the side aldehyde group enhances the interesting electronic properties of the pure anthracene molecule, making it a bistable system with geometry dependent transport properties. We also investigate the transition voltage and we show that conformation-dependent field emission could be observed in these molecular interfaces at realistically low voltages. The present study accompanies our previous work where we investigated the coherent transport via strongly coupled delocalized orbital by application of Non-equilibrium Green's Function Formalism.

  5. Experimental study of the minority-carrier transport at the polysilicon-monosilicon interface

    NASA Astrophysics Data System (ADS)

    Neugroschel, A.; Arienzo, M.; Isaac, R. D.; Komem, Y.

    1985-04-01

    This paper presents the results of an experimental study designed to explore both qualitatively and quantitatively the mechanism of the improved current gain in bipolar transistors with polysilicon emitter contacts. Polysilicon contacts were deposited and heat treated at different conditions. The electrical properties were measured using p-n junction test structures that are much more sensitive to the contact properties than are bipolar transistors. A simple phenomenological model was used to correlate the structural properties with electrical measurements. Possible transport mechanisms are examined and estimates are made about upper bounds on transport parameters in the principal regions of the devices. The main conclusion of this study is that the minority-carrier transport in the polycrystalline silicon is dominated by a highly disordered layer at the polysilicon-monosilicon interface characterized by very low minority-carrier mobility. The effective recombination velocity at the n(+) polysilicon-n(+) monosilicon interface was found to be a strong function of fabrication conditions. The results indicate that the recombination velocity can be much smaller than 10,000 cm/s.

  6. The effect of copolymers on the interfaces in incompatible homopolymers blend: Molecular dynamics study

    NASA Astrophysics Data System (ADS)

    Ryu, Jiho; Lee, Won Bo

    2015-03-01

    Using molecular dynamics simulations the effect of copolymers as compatibilizer for reducing interfacial tension and enhancement of interfacial adhesion at the interface of thermodynamic unfavorable homopolymers blend is studied with block- and graft-copolymers. We have calculated local pressure tensor of system along the axis perpendicular to interface, varying bending potential energy of one part, which consist of just one kind of beads, of copolymer chain to examine the effect of stiffness of surfactin molecules. Here we consider symmetric diblock copolymer (f =1/2) having 1/2 N make of beads of type A and the other part made of beads of type B, and graft copolymer having backbone linear chain consist of 1/2 N beads of type of A and branched with two side-chain consist of 1/4 N beads of type B. All simulations were performed under the constant NPT ensemble at T* =1, ρ* ~0.85. Also we studied changes of effect of copolymers with increasing pairwise repulsive interaction potential between two beads of types A and B while homopolymers chain length are fixed, N =30. Chemical and Biomolecular Engineering, Sogang University, Seoul, South Korea.

  7. Dispersion of pollutants over land-water-land interface: Study using CALPUFF model

    NASA Astrophysics Data System (ADS)

    Indumati, S.; Oza, R. B.; Mayya, Y. S.; Puranik, V. D.; Kushwaha, H. S.

    The CALMET/CALPUFF modeling system is used to study atmospheric dispersion of pollutant over land-water-land interface. It is shown that the default scheme used by CALMET/CALPUFF to handle inhomogeneous surfaces does not take care of the different turbulence characteristics over such surfaces. An alternative method is suggested to incorporate different turbulent characteristics over inhomogeneous surfaces by using the appropriate atmospheric stability category over different surfaces. The results show that the presence of water body can increase the ground level concentration by a factor of up to 50 for the width of water body varying from 1 km to 5 km. It is also shown that the effect of water body on the ground level concentration decreases as the distance from the water body increases. The present study showed that for land-water interface, the realistic specification of turbulence characteristics over inhomogeneous surfaces significantly changes the estimation of ground level concentration as compared to the default scheme available in the CALMET/CALPUFF modeling system and is expected to give realistic results.

  8. Ab initio study of the epitaxial ZrO2 /Si interface

    NASA Astrophysics Data System (ADS)

    Dogan, Mehmet; Kumah, Divine; Ahn, Charles; Walker, Frederick; Ismail-Beigi, Sohrab

    2015-03-01

    Growing thin films of crystalline metal oxides on semiconductors has been of much scientific interest because of the potential applications of such systems in electronic devices. One particular research goal is to achieve ferroelectricity in a crystalline and thin oxide film that is epitaxial on a semiconductor. This would enable one to realize non-volatile field-effect transistors where the state of the system is encoded in the polarization direction of the oxide. In this work, we study oxides that are not ferroelectric in the bulk but become ferroelectric as an ultrathin film on a semiconductor such as silicon. Recent developments in epitaxial growth methods also permit fabrication of such systems. Here, we use density functional theory to study the interface between ZrO2 and Si. When the oxide is only 1 monolayer thick, we find a set of stable structures with a variety of positive and negative out-of-plane ferroelectric polarizations. We present an analysis of these structures as a function of oxide thickness and the size of interface unit cell. Furthermore, the ZrO2 can be used as a buffer layer to induce ferroelectricity in ultrathin perovskite oxides such as SrTiO3 on Si which can couple the oxide polarization to the silicon carrier density. This work is supported by the National Science Foundation through Grant MRSEC NSF DMR-1119826.

  9. NGNP Composites R&D Technical Issues Study

    SciTech Connect

    AREVA Federal Services

    2008-09-01

    This study identifies potential applications and design requirements for ceramic materials (CMs) and ceramic composite materials (CCMs) in the NGNP hightemperature gas-cooled reactor (HTGR) primary circuit. Components anticipated for fabrication from non-graphite CMs and CCMs are identified along with recommended normal and off-normal operating conditions. The evaluation defines required dimensions and material properties of the candidate materials for normal operating conditions (NOC), anticipated transients, abnormal events, and design basis events. The report also identifies additional activities required for codifying the selected materials. The activities include ASTM Standard and ASME Code development and other work to support NRC licensing of the plant. Evaluation of the NGNP baseline design indicates components requiring either CMs or CCMs depend upon the reactor operating temperatures. For a reactor outlet temperature of 900 oC, four of the five evaluated components would benefit from either CMs or CCMs. Although some thermal and mechanical data exist for most of the candidate materials, they all need additional irradiation, thermal, and mechanical testing. The codification process must take into account the type of material and the geometry of components using either CMs or CCMs. The process requires close integration of the design and the research and development (R&D) program, which has already started by using preliminary control rod component designs as the basis for establishing specimen geometry and test conditions. The remaining time and budget for completing the R&D program need further assessment.

  10. Combined sewer overflow: A management study. Technical report

    SciTech Connect

    Reilly, A.

    1988-01-01

    This project is part of the National Network for Environmental Management Studies under the auspices of the Office of Cooperative Environmental Management of the U.S. Environmental Protection Agency. In many older cities in the U.S., the capacity of the combined sewer is exceeded on a daily basis due to both-wet weather storm surges and increased volumes of waste generated by new development. As a result, billions of gallons of untreated sewage are discharged on an annual basis into the nation's marine bays and estuaries in episodes called 'combined sewer overflow.' There are two primary reasons for the increasing frequency and severity of overflow episodes: the population of cities in coastal areas are growing at rates that far exceed the ability of the sewer infrastructure to accommodate them; the built-in inefficiencies of the original design of the combined sewer are being exploited by many municipalities to compensate for the increased volumes of sewage associated with the growth in population. Because each combined sewer, the area that it drains, and the receiving water into which it discharges constitutes a unique system, a management strategy should be site-specific. The document proposes a framework within which a site-specific and cost-effective management strategy may be formulated. By necessity, the emphasis is on providing tools and methods rather than explicit solutions.

  11. Interdisciplinary study of reservoir compartments. Annual technical report

    SciTech Connect

    Van Kirk, C.W.

    1994-10-28

    This DOE research project was established to document the integrated team approach for solving reservoir engineering problems. The goal will be to provide tools and approaches that can be used to detect reservoir compartments, reach a better reserve estimate, and improve profits early in the life of a field. Field selection consumed nearly the first four months of the project. The choice was the Hambert Field area which is the field area being studied. During the remainder of the year, a significant portion of the data was gathered and entered into a data base. Cores have been described, log analysis performed on over 100 wells, and regional mapping and correlation of sedimentary packages completed. Compressional (P) and shear (S) wave velocity data was measured on 8 core plugs at various conditions and lithologies. The analysis of the 3D seismic data has been started and supports the interpretation that the structural component will be a significant factor for reservoir compartmentalization in this reservoir. The experimental permeability work completed includes the pressure decay profile permeability measurements on the cores. Relationships of porosity and permeability with net confining stress were developed. Core relative permeability measurements were also completed during the year. Additional experimental measurements completed include Young`s Modulus, Shear Modulus, Poisson`s ratio, and the bulk compressibility as a function of the effective stress. Preliminary engineering analysis of the pressure build-up data from two wells supports the conclusion that sealing faults may act as barriers to flow.

  12. A study of System Interface Sets (SIS) for the host, target and integration environments of the Space Station Program (SSP)

    NASA Technical Reports Server (NTRS)

    Mckay, Charles; Auty, David; Rogers, Kathy

    1987-01-01

    System interface sets (SIS) for large, complex, non-stop, distributed systems are examined. The SIS of the Space Station Program (SSP) was selected as the focus of this study because an appropriate virtual interface specification of the SIS is believed to have the most potential to free the project from four life cycle tyrannies which are rooted in a dependance on either a proprietary or particular instance of: operating systems, data management systems, communications systems, and instruction set architectures. The static perspective of the common Ada programming support environment interface set (CAIS) and the portable common execution environment (PCEE) activities are discussed. Also, the dynamic perspective of the PCEE is addressed.

  13. STEM integration in middle school career and technical education programs: A Delphi design study

    NASA Astrophysics Data System (ADS)

    Wu-Rorrer, Billy Ray

    The purpose of this qualitative method study with a Delphi research design sought to determine how STEM programs can be effectively integrated into middle school career and technical education programs by local, state, and national educators, administrators, directors, specialists, and curriculum writers. The significance of the study is to provide leaders in CTE with a greater awareness, insight, and strategies about how CTE programs can more effectively integrate academics into career and technical education programs through STEM-related programming. The findings will increase the limited amount of available literature providing best practice strategies for the integration of STEM curriculum into middle school CTE programs. One basic question has guided this research: How can STEM programs be effectively integrated into middle school career and technical education programs? A total of twelve strategies were identified. The strategies of real-world applications and administrative buy-in were the two predominant strategies consistently addressed throughout the review of literature and all three sub-questions in the research study. The Delphi design study consisted of pilot round and three rounds of data collection on barriers, strategies, and professional development for STEM integration in middle school career and technical education programs. Four panelists participated in the pilot round, and 16 panel members not involved in the pilot round participated in the three rounds of questioning and consensus building. In the future, more comprehensive studies can build upon this foundational investigation of middle school CTE programs.

  14. Design of a monochromatic ellipsometer for studies at the solid-liquid interface

    NASA Astrophysics Data System (ADS)

    Pai-Panandiker, R. S.; Dorgan, J. R.

    1995-02-01

    A new design for a monochromatic ellipsometer used for studies at the solid-liquid interface is described. The design of the ellipsometer incorporates two novel features—a special optical glass cell and a thermally controlled sample oven. The ellipsometer design allows for in situ kinetic studies through use of the optical glass cell. Furthermore, the apparatus is modified to allow thermal equilibration over a range of temperatures. The temperature response of the cell assembly is presented and the response time is seen to be approximately 1 h. Data on the adsorption of a diblock copolymer [poly(ethylene oxide)-block-polystyrene] are presented; the analyzed data agree with previous studies on the same system.

  15. Atmospheric, Magnetospheric and Plasmas in Space (AMPS) spacelab payload definition study. Volume 3: Interface control documents. Part 2: AMPS payload to spacelab ICD

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The AMPS to Spacelab Interface Control Document which is to be used as a guide for format and information content in generating specific AMPS Mission ICDs is presented. This document is meant to supplement the Spacelab Payload Accommodations Handbook in that it only defines interfaces which are not discussed in the handbook to the level required for design purposes. The AMPS Top Level Requirements Tree, illustrates this ICD by a shaded area and its relationship to the other AMPS technical documents. Other interface documents shown are the Level II, AMPS to Space Shuttle Vehicle ICD and the Level III, AMPS to Instruments ICD.

  16. A Multi-Experimental Study on the Use of Multimedia Instructional Materials to Teach Technical Subjects

    ERIC Educational Resources Information Center

    Mbarika, Victor; Bagarukayo, Emily; Hingorani, Vineeta; Stokes, Sandra; Kourouma, Mathieu; Sankar, Chetan

    2010-01-01

    A review of "social experiments" with adoption of multimedia-based technologies in Europe has been reported. But, there has been limited discussion on the value of multimedia instructional materials in technical disciplines. This study combines results from experiments carried out over a period of three years with multiple audiences--IT managers…

  17. Participation in Formal Technical and Vocational Education and Training Programmes Worldwide: An Initial Statistical Study

    ERIC Educational Resources Information Center

    UNESCO-UNEVOC International Centre for Technical and Vocational Education and Training, 2006

    2006-01-01

    There is a common perception that technical and vocational education and training (TVET) is diversifying and expanding in terms of its supply and demand. Practitioners and policymakers often believe that educational systems are offering a wider array of programmes at different levels and in various fields of study. They also assume that these…

  18. A Technical, User and Cost Comparison Study of Microfiche Duplicate Film Material. Final Report.

    ERIC Educational Resources Information Center

    Prevel, James J.

    A technical, user and cost comparison study was undertaken to provide the Educational Resources Information Clearinghouse (ERIC) staff with data on silver halide, diazo, and vesicular type films for microfiche duplication. This information will allow ERIC to determine if diazo and/or vesicular films should be considered in producing ERIC duplicate…

  19. Career and Technical Education Students Who Transition to Four-Year Institutions: An Exploratory Study

    ERIC Educational Resources Information Center

    Qi, Wen; Cole, James S.

    2011-01-01

    Each year more students with career and technical education (CTE) backgrounds are transitioning to four-year institutions. This exploratory study investigated differences between CTE, community college transfers and native (nontransfer) students at four-year institutions in regard to how they balance their time and their academic engagement…

  20. Challenge Study: A Project-Based Learning on a Wireless Communication System at Technical High School

    ERIC Educational Resources Information Center

    Terasawa, Ikuo

    2016-01-01

    The challenge study is a project based learning curriculum at Technical High School aimed at the construction of a wireless communication system. The first period was engineering issues in the construction of an artificial satellite and the second period was a positional locating system based on the general purpose wire-less device--ZigBee device.…

  1. Policies and Guidelines for Educational and Vocational Guidance. Studies on Technical and Vocational Education 1.

    ERIC Educational Resources Information Center

    Conger, D. Stuart

    This book is the first in a series aiming to promote international exchange of ideas, experiences, and studies relating to technical and vocational education. Recommendations for educational and vocational guidance policies and programs are given. Part 1 lists the goals of guidance: for students to know and appreciate themselves, to relate…

  2. Research Study on Planning for Connecticut Regional Vocational-Technical Schools. Final Report.

    ERIC Educational Resources Information Center

    University Research Inst. of Connecticut, Inc., Wallingford.

    To help determine the feasibility of establishing in any Connecticut town new regional vocational-technical schools that would not produce any adverse effects on existing schools, this research study presents a methodology and computerized program by which these assessments may be made. Part One discusses the need for this type of methodology and…

  3. Interpretive Discourse and Other Models from Communication Studies: Expanding the Values of Technical Communication

    ERIC Educational Resources Information Center

    Williams, Sean D.

    2010-01-01

    This article argues that in spite of some attempts to expand the diversity of approaches in Technical Communication, the field remains rooted in an expedient, managerial, techno-rational discourse, where discourse is understood as the values that guide research, practice, and teaching. The article draws on approaches from Communication Studies,…

  4. Situating Programs of Study within Current and Historical Career and Technical Educational Reform Efforts

    ERIC Educational Resources Information Center

    Stipanovic, Natalie; Lewis, Morgan V.; Stringfield, Sam

    2012-01-01

    This article provides a broad overview of the history of career-focused education in the United States and the reauthorization of the federal Carl D. Perkins Career and Technical Education Improvement Act of 2006. The Perkins act required that the recipients of its funding offer at least one program of study, and this reauthorization included four…

  5. Globalizing Writing Studies: The Case of U.S. Technical Communication Textbooks

    ERIC Educational Resources Information Center

    Matsuda, Aya; Matsuda, Paul Kei

    2011-01-01

    In an increasingly globalized world, writing courses, situated as they are in local institutional and rhetorical contexts, need to prepare writers for global writing situations. Taking introductory technical communication in the United States as a case study, this article describes how and to what extent global perspectives are incorporated into…

  6. Space station automation study: automation requirements derived from space manufacturing concepts. Volume II: final technical report

    SciTech Connect

    Not Available

    1984-11-27

    The purpose of the Space Station Automation Study is to develop informed technical guidance to NASA in the use of autonomy and autonomous systems to implement space station functions. Some topics discussed include mission selection, GaAs electroepitaxial crystal production, and the GaAs microelectronics chip facility.

  7. Predisposition Factors of Career and Technical Education Transfer Students: A Hermeneutic Phenomenology Study

    ERIC Educational Resources Information Center

    Hioki, Warren; Lester, Derek; Martinez, Mario

    2015-01-01

    Six college students, who were career and technical education (CTE) transfer students in the state of Nevada, were interviewed Spring Semester of 2009. The study used a hermeneutic phenomenology framework as the method to identify those predisposition variables that heavily influenced the students in their decision to transfer to a senior…

  8. A Study of Technical Signs in Science: Implications for Lexical Database Development

    ERIC Educational Resources Information Center

    Lang, Harry G.; Hupper, Mary LaPorta; Monte, Denise A.; Brown, Scott W.; Babb, Ivar; Scheifele, Pete M.

    2007-01-01

    Both classroom instruction and lexical database development stand to benefit from applied research on sign language, which takes into consideration American Sign Language rules, pedagogical issues, and teacher characteristics. In this study of technical science signs, teachers' experience with signing and, especially, knowledge of content, were…

  9. A Feasibility Study for Consolidating and/or Coordinating Technical Procedures in Beaver County Pennsylvania Libraries.

    ERIC Educational Resources Information Center

    Fry, James W.

    In 1977 the Public Library Commission, in conjunction with the State Library of Pennsylvania, received a Library Services and Construction Act, Title III Grant to conduct a feasibility study of technical service operations in various types of libraries within Beaver County. Its objectives were to: (1) analyze existing library materials purchasing…

  10. A Study of Student Persisters and Nonpersisters in the Community and Technical College.

    ERIC Educational Resources Information Center

    Smith, Alan D.

    1982-01-01

    Describes a study of factors related to student attrition at the University of Akron's General College and Community and Technical College. Analyzes data on persisters/nonpersisters, males/females, and traditional/nontraditional students with respect to major, full-/part-time status, time of attendance, goals, and satisfaction with the college.…

  11. Methodology in Seeking Stakeholder Perceptions of Effective Technical Oral Presentations: An Exploratory Pilot Study

    ERIC Educational Resources Information Center

    Bhattacharyya, Ena; Patil, Arun; Sargunan, Rajeswary Appacutty

    2010-01-01

    Engineering communication studies indicate the importance of oral presentations as an indispensable component of workplace oral communication activities; however, since there is limited literature regarding stakeholder perceptions of effective presentation skills and attributes in technical oral presentations or final year engineering project…

  12. Organising, Providing and Evaluating Technical Training for Early Career Researchers: A Case Study

    ERIC Educational Resources Information Center

    van Besouw, Rachel M.; Rogers, Katrine S.; Powles, Christopher J.; Papadopoulos, Timos; Ku, Emery M.

    2013-01-01

    This paper considers the importance of providing technical training opportunities for Early Career Researchers (ECRs) worldwide through the case study of a MATLAB training programme, which was proposed, organised, managed and evaluated by a team of five ECRs at the University of Southampton. The effectiveness of the programme in terms of the…

  13. Introduction: Policy and Technical Contexts of National Assessment of Educational Progress Validity Studies.

    ERIC Educational Resources Information Center

    Baker, Eva L.

    1996-01-01

    A series of studies by the Technical Review Panel (TRP) of the National Assessment of Educational Progress (NAEP) to improve the quality and utility of the NAEP is introduced, with a description of the NAEP, the creation of the TRP, the education policy issues that influenced the selection of research topics, and the relationship among the…

  14. Technical Manual for the Texas Successful Schools Study: Quality Education for Limited English Proficient Students.

    ERIC Educational Resources Information Center

    Texas Education Agency, Austin.

    The Texas Successful Schools Study examined the educational practices, school characteristics, and educator characteristics that contributed to the success of seven high-performing elementary schools with high proportions of limited-English-proficient (LEP) and economically disadvantaged students. This technical manual further elaborates the…

  15. Technical Training in the MNCs in Malaysia: A Case Study Analysis of the Petrochemical Industry

    ERIC Educational Resources Information Center

    Hooi, Lai Wan

    2010-01-01

    Purpose: The aim of this paper is to gain insight into some of the types of training and development practices that are carried out in the chemical industry for technical workers. A salient focus of the study is to make a comparative analysis of four MNCs, which were selected based on equity ownership, to ascertain whether T&D practices are…

  16. 1993 Pacific Northwest Loads and Resources Study, Technical Appendix: Volume 2, Book 1, Energy.

    SciTech Connect

    United States. Bonneville Power Administration.

    1993-12-01

    The 1993 Pacific Northwest Loads and Resources Study establishes the Bonneville Power Administration`s (BPA) planning basis for supplying electricity to BPA customers. The Loads and Resources Study is presented in three documents: (1) this technical appendix detailing loads and resources for each major Pacific and Northwest generating utility, (2) a summary of Federal system and Pacific Northwest region loads and resources, and (3) a technical appendix detailing forecasted Pacific Northwest economic trends and loads. This analysis updates the 1992 Pacific Northwest Loads and Resources Study Technical Appendix published in December 1992. This technical appendix provides utility-specific information that BPA uses in its long-range planning. It incorporates the following for each utility (1) Electrical demand firm loads; (2) Generating resources; and (3) Contracts both inside and outside the region. This document should be used in combination with the 1993 Pacific Northwest Loads and Resources Study, published in December 1993, because much of the information in that document is not duplicated here.

  17. Study of Au/TiO2 interface structure using Energy Density Method

    NASA Astrophysics Data System (ADS)

    Yu, Min; Trinkle, Dallas R.; Martin, Richard M.

    2010-03-01

    We propose a way to decompose the total energy in a material into the contribution associated with each of the atoms, using the first principles energy density formalism[1]. Although the energy density function is non-unique up to a gauge transformation, we show that unique defect energies can be found by defining volumes for each atoms using the Bader charge analysis[2]. The methods are applied to gold nanoclusters supported on rutile titanium dioxide, which are commonly used as catalysts for chemical reactions. The variation in structure and chemistry of the interface may affect catalytic acticity. In this work, we study four model interfaces; Au(111)//TiO2(110) and Au(100)//TiO2(110), with and without bridging oxygen. Calculations are performed using the projector augmented wave method implemented in the Vienna ab initio simulation package[3], and the energy density method computes the interfacial energies to determine the equlibrium interfacial structure. [1]Phys. Rev. B 45, 6074 (1992) [2]Comput. Mater. Sci. 36, 254 (2006) [3]Phys. Rev. B 59, 1758 (1999)

  18. A comparative experimental study on structural and interface damping approaches for vibration suppression purposes

    NASA Astrophysics Data System (ADS)

    Liu, Yi; Sanchez, Alberto; Zogg, Markus; Ermanni, Paolo

    2010-04-01

    Dynamic loadings in automotive structures may lead to reduction of driving comfort and even to failure of the components. Damping treatments are applied in order to attenuate the vibrations and improve the long term fatigue behavior of the structures. This experimental study is targeting applications in floor panels that are mounted to the loadcarrying primary structure of the vehicle. The objective is to reach outstanding damping performance considering the stringent weight and cost requirement in the automotive industry. An experimental setup has been developed and validated for the determination of the damping properties of structural specimens also considering interface damping effects. This contribution is structured in three main parts: test rig design, experimental results and discussion. Reliable and easy-to-use devices for the characterization of the damping properties of specimens between 200×40 mm2 and 400×400 mm2 are not available "on the shelf". In this context, we present a flexible experimental set-up which has been realized to (1) support the development of novel damping solutions for multi-functional composite structures; (2) characterize the loss-factor of the different damping concepts, including boundary effects. A variety of novel passive and active damping treatments have been investigated including viscoelastic, coulomb, magnetorheological (MR), particle, magnetic and eddy current damping. The particle, interface as well as active damping systems show promising performance in comparison to the classical viscoelastic treatments.

  19. A control volume study of the pressure tensor across a liquid-vapour interface

    NASA Astrophysics Data System (ADS)

    Braga, Carlos; Yatsyshin, Petr; Smith, Edward; Nold, Andreas; Goddard, Benjamin; Savva, Nikos; Schmuck, Markus; Duncan, Andrew; Sibley, David; Kalliadasis, Serafim

    2015-11-01

    The presence of an interface renders the properties of the system position dependent. The pressure tensor will no longer be uniform nor isotropic giving rise to the surface tension. The theory of Kirkwood-Buff gives a formal description of the surface tension based on the analysis of the local pressure tensor while capillary wave theory assumes the existence of an instantaneous intrinsic surface separating the liquid and vapour. Analysis of its Fourier components gives both structural and dynamical routes to compute the surface based on hydrodynamic theory. The defining equation of a capillary surface is given by the stress balance between the pressure tensors and the surface tension. Here, we employ the instantaneous interface as a representative surface across which we compute the local pressures following the seminal work of Irving and Kirkwood. The control volume approach to the Irving-Kirkwood expressions provides an exact balance between the stress and momentum transfer across the surface element allowing the study of the surface tension from a mechanical standpoint. We acknowledge financial support from European Research Council via Advanced Grant No. 247031.

  20. A novel tribological study on DLC-coated micro-dimpled orthopedics implant interface.

    PubMed

    Choudhury, Dipankar; Urban, Filip; Vrbka, Martin; Hartl, Martin; Krupka, Ivan

    2015-05-01

    This study investigates a tribological performance of diamond like carbon (DLC) coated micro dimpled prosthesis heads against ceramic cups in a novel pendulum hip joint simulator. The simulator enables determining friction coefficient and viscous effects of a concave shaped specimen interface (conformal contact). Two types of DLC such as hydrogenated amorphous carbon (a-C:H) and tetrahedral amorphous carbon (Ta-C) and one set of micro dimple (diameter of 300µm, depth of 70µm, and pitch of 900µm) were fabricated on metallic prosthesis heads. The experiment results reveal a significant friction coefficient reduction to the 'dimpled a-C:H/ceramic' prosthesis compared to a 'Metal (CoCr)/ceramic' prosthesis because of their improved material and surface properties and viscous effect. The post-experiment surface analysis displays that the dimpled a-C:H yielded a minor change in the surface roughness, and generated a larger sizes of wear debris (40-200nm sized, equivalent diameter), a size which could be certainly stored in the dimple, thus likely to reducing their possible third body abrasive wear rate. Thus, dimpled a:C-H can be used as a 'metal on ceramic hip joint interface', whereas the simulator can be utilized as an advanced bio-tribometer. PMID:25704181

  1. Study of Hydrophobic and Ionizable Hydrophilic Copolymers at Polymer/Solid and Polymer/Liquid Interfaces

    SciTech Connect

    Perahia, Dvora

    2011-11-01

    Joint experimental-computational efforts were set to characterize the interfacial effects on the structure and dynamics of polymers consisting of highly rigid hydrophilic-ionizable and hydrophobic sub-units within one polymeric chain casted into thin films of several molecular dimensions. Focusing on the ultra thin film region we separate out the interfacial effects from bulk characteristics. Specifically, the study sought to: identify the parameters that control the formation of a stable polymer-solid interface. The study consists of two components, experimental investigations and computational efforts. The experimental component was designed to derive empirical trends that can be used to correlate the set of coupled polymer molecular parameters with the interfacial characteristics of these polymers, and their response to presence of solvents. The computational study was designed to provide molecular insight into the ensemble averages provided by the experimental efforts on multiple length scales from molecular dimensions, to the nanometer lengths to a macroscopic understanding of solvent interactions with structured polymers. With the ultimate goal of correlating molecular parameters to structure, dynamics and properties of ionic polymers, the first stage of the research began with the study of two systems, one which allowed tailoring the flexibility of the backbone without the presence of ionic groups, but with a potential to sulfonate groups at a later stage, and a polymer whose backbone is rigid and the density of the ionic group can be varied. The combined experimental and computational studies significantly extended the understanding of polymers at interfaces from model systems to polydispersed copolymers with blocks of varying nature and complexity. This new insight directly affects the design of polymers for sustainable energy applications from batteries and fuel cells to solar energy.

  2. Space transfer vehicle concepts and requirements study. Volume 2, book 3: STV system interfaces

    NASA Technical Reports Server (NTRS)

    Weber, Gary A.

    1991-01-01

    This report presents the results of systems analyses and conceptual design of space transfer vehicles (STV). The missions examined included piloted and unpiloted lunar outpost support and spacecraft servicing, and unpiloted payload delivery to various earth and solar orbits. The study goal was to examine the mission requirements and provide a decision data base for future programmatic development plans. The final lunar transfer vehicles provided a wide range of capabilities and interface requirements while maintaining a constant payload mission model. Launch vehicle and space station sensitivity was examined, with the final vehicles as point design covering the range of possible options. Development programs were defined and technology readiness levels for different options were determined. Volume 1 presents the executive summary, volume 2 provides the study results, and volume 3 the cost and WBS data.

  3. Gas transfer - A gas tension method for studying equilibration across a gas-water interface

    NASA Astrophysics Data System (ADS)

    Anderson, Meredith L.; Johnson, Bruce D.

    1992-11-01

    New strategies are required in the study of gas exchange under energetic and changeable conditions where current techniques are limited, especially in their ability to represent the contribution of injected bubbles. We have developed a gas tension device (GTD) that uses a solid-state differential pressure sensor to make continuous in situ measurements of the difference between pressure of dissolved gas (gas tension, for succinctness) and pressure of gas in the gas phase above a water parcel. This information allows the determination of the rate of approach to a dynamic equilibrium and of the degree of water phase saturation at steady state. The method is demonstrated in the lab by following the invasion of CO2 into seawater with bubble injection. The GTD introduces a new and versatile measurement method for the study of gas transfer across air-water interfaces, one which avoids many of the sampling and bias problems of traditional approaches.

  4. Fluxes across double-diffusive interfaces: a one-dimensional-turbulence study

    NASA Astrophysics Data System (ADS)

    Gonzalez, E.; Kerstein, A.; Lignell, D.

    2010-12-01

    Double-diffusive convection in the diffusive regime is believed to occur, for example, in the Arctic and Southern Oceans, in geothermally-heated salty lakes, and in massive stars and giant planets. It is of interest in all these systems to know the parametrization of the fluxes of heat and salt across double-diffusive interfaces. The present work is a parametric study of these fluxes using one-dimensional-turbulence (ODT) simulations. Its main distinction is that it considers a parameter space larger than previous studies, which includes the effect of background shear. Specifically, this work considers the effect on the fluxes of the stability parameter, Rayleigh number, Prandtl number, Lewis number, and Richardson number. The ratio of the Rayleigh number and the stability parameter is found to be a dominant parameter. This parameter can be seen as a ratio of destabilizing and stabilizing effects. Trends predicted by the simulations are in good agreement with previous models and available measurements.

  5. Brewster Angle Microscopy Study of Model Stratum Corneum Lipid Monolayers at the Air-Water Interface

    NASA Astrophysics Data System (ADS)

    Adams, Ellen; Champagne, Alex; William, Joseph; Allen, Heather

    2012-04-01

    As the first and last barrier in the body, the stratum corneum (SC) is essential to life. Understanding the interactions and organization of lipids within the SC provides insight into essential physiological processes, including water loss prevention and the adsorption of substances from the environment. Langmuir monolayers have long been used to study complex systems, such as biological membranes and marine aerosols, due to their ability to shed light on intermolecular interactions. In this study, lipid mixtures with varying cholesterol and cerebroside ratios were investigated at the air/water interface. Surface tension measurements along with Brewster angle microscopy (BAM) images were used to examine the lipid phase transitions. Results indicate that cholesterol and cerebrosides form miscible monolayers, exhibiting ideal behavior. BAM images of a singular, uniform collapse phase also suggest formation of a miscible monolayer.

  6. Effect of Single-Electron Interface Trapping in Decanano MOSFETs: A 3D Atomistic Simulation Study

    NASA Technical Reports Server (NTRS)

    Asenov, Asen; Balasubramaniam, R.; Brown, A. R.; Davies, J. H.

    2000-01-01

    We study the effect of trapping/detrapping of a single-electron in interface states in the channel of n-type MOSFETs with decanano dimensions using 3D atomistic simulation techniques. In order to highlight the basic dependencies, the simulations are carried out initially assuming continuous doping charge, and discrete localized charge only for the trapped electron. The dependence of the random telegraph signal (RTS) amplitudes on the device dimensions and on the position of the trapped charge in the channel are studied in detail. Later, in full-scale, atomistic simulations assuming discrete charge for both randomly placed dopants and the trapped electron, we highlight the importance of current percolation and of traps with strategic position where the trapped electron blocks a dominant current path.

  7. Neuromechanism study of insect-machine interface: flight control by neural electrical stimulation.

    PubMed

    Zhao, Huixia; Zheng, Nenggan; Ribi, Willi A; Zheng, Huoqing; Xue, Lei; Gong, Fan; Zheng, Xiaoxiang; Hu, Fuliang

    2014-01-01

    The insect-machine interface (IMI) is a novel approach developed for man-made air vehicles, which directly controls insect flight by either neuromuscular or neural stimulation. In our previous study of IMI, we induced flight initiation and cessation reproducibly in restrained honeybees (Apis mellifera L.) via electrical stimulation of the bilateral optic lobes. To explore the neuromechanism underlying IMI, we applied electrical stimulation to seven subregions of the honeybee brain with the aid of a new method for localizing brain regions. Results showed that the success rate for initiating honeybee flight decreased in the order: α-lobe (or β-lobe), ellipsoid body, lobula, medulla and antennal lobe. Based on a comparison with other neurobiological studies in honeybees, we propose that there is a cluster of descending neurons in the honeybee brain that transmits neural excitation from stimulated brain areas to the thoracic ganglia, leading to flight behavior. This neural circuit may involve the higher-order integration center, the primary visual processing center and the suboesophageal ganglion, which is also associated with a possible learning and memory pathway. By pharmacologically manipulating the electrically stimulated honeybee brain, we have shown that octopamine, rather than dopamine, serotonin and acetylcholine, plays a part in the circuit underlying electrically elicited honeybee flight. Our study presents a new brain stimulation protocol for the honeybee-machine interface and has solved one of the questions with regard to understanding which functional divisions of the insect brain participate in flight control. It will support further studies to uncover the involved neurons inside specific brain areas and to test the hypothesized involvement of a visual learning and memory pathway in IMI flight control. PMID:25409523

  8. Neuromechanism Study of Insect–Machine Interface: Flight Control by Neural Electrical Stimulation

    PubMed Central

    Zhao, Huixia; Zheng, Nenggan; Ribi, Willi A.; Zheng, Huoqing; Xue, Lei; Gong, Fan; Zheng, Xiaoxiang; Hu, Fuliang

    2014-01-01

    The insect–machine interface (IMI) is a novel approach developed for man-made air vehicles, which directly controls insect flight by either neuromuscular or neural stimulation. In our previous study of IMI, we induced flight initiation and cessation reproducibly in restrained honeybees (Apis mellifera L.) via electrical stimulation of the bilateral optic lobes. To explore the neuromechanism underlying IMI, we applied electrical stimulation to seven subregions of the honeybee brain with the aid of a new method for localizing brain regions. Results showed that the success rate for initiating honeybee flight decreased in the order: α-lobe (or β-lobe), ellipsoid body, lobula, medulla and antennal lobe. Based on a comparison with other neurobiological studies in honeybees, we propose that there is a cluster of descending neurons in the honeybee brain that transmits neural excitation from stimulated brain areas to the thoracic ganglia, leading to flight behavior. This neural circuit may involve the higher-order integration center, the primary visual processing center and the suboesophageal ganglion, which is also associated with a possible learning and memory pathway. By pharmacologically manipulating the electrically stimulated honeybee brain, we have shown that octopamine, rather than dopamine, serotonin and acetylcholine, plays a part in the circuit underlying electrically elicited honeybee flight. Our study presents a new brain stimulation protocol for the honeybee–machine interface and has solved one of the questions with regard to understanding which functional divisions of the insect brain participate in flight control. It will support further studies to uncover the involved neurons inside specific brain areas and to test the hypothesized involvement of a visual learning and memory pathway in IMI flight control. PMID:25409523

  9. X-ray studies of III-V native oxide/gallium arsenide interface

    NASA Astrophysics Data System (ADS)

    Cheong, Seong-Kyun

    Three x-ray techniques have been employed to study wet-thermal native oxides of AlGaAs on GaAs. For these materials, a knowledge of the role of As at the interface is important for understanding Fermi-level pinning and is a central issue in efforts to develop high performance III-V MOSFET devices. This study is focused on how the As is incorporated at the interface, the interfacial strain, and related local structural parameters. X-ray absorption fine-structure spectroscopy (XAFS) was used to determine the site of residual As in wet-oxidized Al0.96Ga0.04As. In a ˜0.5 mum oxide film removed from its GaAs substrate, the remaining As atoms were found to be coordinated with oxygen in the form of amorphous As oxides, with a mixture of ˜80% As3+ and ˜20% As 5+ sites. These two sites are locally similar to As2O 3 and As2O5. Through this measurement, no evidence of interstitial or substitutional As, As precipitates, or GaAs was seen, implying that less than 10% of the As atoms are in these forms. To characterize the oxide structure in both the oxide film and the interfacial region, x-ray reflectivity and reflection-mode XAFS experiments were performed for a thin (300 A) oxidized AlxGa1-xAs (x = 0.96) film grown on GaAs. X-ray reflectivity studies showed that the composition of the surface oxidized film is not homogeneous as a function of depth. Reflection-mode XAFS, which uses the total external reflection of x-rays to confine an x-ray beam to the interfacial region, provided details of the local environment of As atoms at the interface of the oxide/GaAs. Analysis through this technique revealed that As atoms are in the form of mixed As oxides, with the local environment appearing to resemble As2O3 and As 2O5 in the interfacial region, which is consistent with the above observation from the isolated oxide film.

  10. Electronic and magnetic properties at rough alloyed interfaces of Fe/Co on Au substrates: An augmented space study

    NASA Astrophysics Data System (ADS)

    Priyadarshini, Parida; Biplab, Ganguli

    2016-05-01

    We studied the interface electronic and magnetic properties of Fe/Co deposited on Au substrate and researched the effects of roughness at the interfaces within augmented space formalism (ASF). The full calculation is carried out by recursion and tight-binding linear muffin tin orbital (TB-LMTO) methods. The amount of roughness is different at different atomic layers. The formalism is also applied to sharp interface, when interdiffusion of atoms is negligible. Our results of one monolayer transition metal agree with other reported results. A realistic rough interface is also modeled with three and four monolayers of transition metals, deposited on Au substrates. Project supported by the INSPIRE Program Division, Department of Science and Technology, India.

  11. Case study for the evaluation and selection of man-machine interface (MMI) software

    SciTech Connect

    Nekimken, H.; Pope, N.; Macdonald, J.; Bibeau, R.; Gomez, B.; Sellon, D.

    1996-06-01

    The authors evaluated three of the top man-machine interface (MMI) software systems. The main categories upon which they based their evaluation on were the following: operator interface; network and data distribution; input/output (I/O) interface; application development; alarms; real-time and historical trending; support, documentation, and training; processing tools (batch, recipe, logic); reports; custom interfacing; start-up/recovery; external database; and multimedia. They also present their MMI requirements and guidelines for the selection and evaluation of these MMI systems.

  12. Earth Observatory Satellite system definition study. Report 2: Instrument constraints and interfaces

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The instrument constraints and interface specifications for the Earth Observatory Satellite (EOS) are discussed. The Land Use Classification Mission using a 7 band Thematic Mapper and a 4 band High Resolution Pointable Imager is stressed. The mission and performance of the instruments were reviewed and expanded to reflect the instrument as a part of the total remote sensing system. A preliminary EOS interface handbook is provided to describe the mission and system, to specify the spacecraft interfaces to potential instrument contractors, and to describe the instrument interface data required by the system integration contractor.

  13. Poisson-Boltzmann study of the effective electrostatic interaction between colloids at an electrolyte interface

    NASA Astrophysics Data System (ADS)

    Majee, Arghya; Bier, Markus; Dietrich, S.

    2016-08-01

    The effective electrostatic interaction between a pair of colloids, both of them located close to each other at an electrolyte interface, is studied by employing the full, nonlinear Poisson-Boltzmann (PB) theory within classical density functional theory. Using a simplified yet appropriate model, all contributions to the effective interaction are obtained exactly, albeit numerically. The comparison between our results and those obtained within linearized PB theory reveals that the latter overestimates these contributions significantly at short inter-particle separations. Whereas the surface contributions to the linear and the nonlinear PB results differ only quantitatively, the line contributions show qualitative differences at short separations. Moreover, a dependence of the line contribution on the solvation properties of the two adjacent fluids is found, which is absent within the linear theory. Our results are expected to enrich the understanding of effective interfacial interactions between colloids.

  14. Impact of Participatory Design for Drug-Drug Interaction Alerts. A Comparison Study Between Two Interfaces.

    PubMed

    Luna, Daniel; Otero, Carlos; Risk, Marcelo; Stanziola, Enrique; González Bernaldo de Quirós, Fernán

    2016-01-01

    Decision support systems for alert drug-drug interactions have been shown as valid strategy to reduce medical error. Even so the use of these systems has not been as expected, probably due to the lack of a suitable design. This study compares two interfaces, one of them developed using participatory design techniques (based on user centered design processes). This work showed that the use of these techniques improves satisfaction, effectiveness and efficiency in an alert system for drug-drug interactions, a fact that was evident in specific situations such as the decrease of errors to meet the specified task, the time, the workload optimization and users overall satisfaction with the system. PMID:27577343

  15. Studies on electronic structure of interfaces between Ag and gelatin for stabilization of Ag nanoparticles

    NASA Astrophysics Data System (ADS)

    Tani, Tadaaki; Uchida, Takayuki

    2015-06-01

    Extremely high stability of Ag nanoparticles in photographic materials has forced us to study the electronic structures of the interfaces between thin layers of Ag, Au, and Pt and their surface membranes in ambient atmosphere by photoelectron yield spectroscopy in air and Kelvin probe method. Owing to the Fermi level equalization between a metal layer and a membrane coming from air, the electron transfer took place from the membrane to Pt and Au layers and from an Ag layer to the membrane, giving the reason for poor stability of Ag nanoparticles in air. The control of the Fermi level of an Ag layer with respect to that of a gelatin membrane in air could be widely made according to Nernst’s equation by changing the pH and pAg values of an aqueous gelatin solution used to form the membrane, and thus available to stabilize Ag nanoparticles in a gelatin matrix.

  16. Thermal study of interface between the Orbiter cold plate and typical Shuttle spacecraft payload flight electronics

    NASA Technical Reports Server (NTRS)

    Hwangbo, H.; Coyle, M. J.

    1979-01-01

    Spacelab provides a set of Freon line plumbing and cold plates for experiment equipments which are located in the Shuttle pallet and which need active thermal control. The reported study deals with the thermal problem of attaching a Command and Data Handling module with various electronic boxes whose combined footprints on the baseplate are much larger than the cold plate. A description of two modules and the cold plate assembly in the pallet is presented and a thermal model description is provided. The method employed in modeling heat pipes-honey-comb matrix is based upon an effective conductance between the heat pipe vapor and the walls of the heat pipe. The considered thermal models and a computer program are used to perform steady-state thermal analyses. The temperature gradients in the large module baseplate attached to the small cold plate are predicted as a function of the interface plate thickness.

  17. Density-functional study of the nematic-isotropic interface of hard spherocylinders.

    PubMed

    Velasco, E; Mederos, L; Sullivan, D E

    2002-08-01

    The Somoza-Tarazona density-functional theory is applied to the isotropic-nematic interface of hard spherocylinders with length (L)-to-diameter (D) ratios in the range L/D=5-20. Properties such as the density and orientational order-parameter profiles and the variation of interfacial tension with bulk nematic tilt angle agree qualitatively with results of previous studies at larger values of L/D using both computer simulation and the Onsager second-virial approximation. The minimum interfacial tension is obtained at a tilt angle of 90 degrees. For values of L/D approximately 5, it is found that the Onsager approximation predicts a spurious minimum in the interfacial tension at small tilt angles. PMID:12241197

  18. Photoemission spectroscopy study of the lanthanum lutetium oxide/silicon interface

    SciTech Connect

    Nichau, A.; Schnee, M.; Schubert, J.; Bernardy, P.; Hollaender, B.; Buca, D.; Mantl, S.; Besmehn, A.; Breuer, U.; Rubio-Zuazo, J.; Castro, G. R.; Muecklich, A.; Borany, J. von

    2013-04-21

    Rare earth oxides are promising candidates for future integration into nano-electronics. A key property of these oxides is their ability to form silicates in order to replace the interfacial layer in Si-based complementary metal-oxide field effect transistors. In this work a detailed study of lanthanum lutetium oxide based gate stacks is presented. Special attention is given to the silicate formation at temperatures typical for CMOS processing. The experimental analysis is based on hard x-ray photoemission spectroscopy complemented by standard laboratory experiments as Rutherford backscattering spectrometry and high-resolution transmission electron microscopy. Homogenously distributed La silicate and Lu silicate at the Si interface are proven to form already during gate oxide deposition. During the thermal treatment Si atoms diffuse through the oxide layer towards the TiN metal gate. This mechanism is identified to be promoted via Lu-O bonds, whereby the diffusion of La was found to be less important.

  19. Computational Studies of [Bmim][PF6]/n-Alcohol Interfaces with Many-Body Potentials

    SciTech Connect

    Chang, Tsun-Mei; Dang, Liem X.

    2014-09-04

    In this paper, we present the results from molecular-dynamics simulations of the equilibrium properties of liquid/liquid interfaces of room temperature ionic liquid [bmim][PF6] and simple alcohols (i.e., methanol, 1-butanol, and 1-hexanol) at room temperature. Polarizable potential models are employed to describe the interactions among species. Results from our simulations show stable interfaces between the ionic liquid and n-alcohols, and we found that the interfacial widths decrease from methanol to 1-butanol systems, and then increase for 1-hexanol interfaces. Angular distribution analysis reveals that the interface induces a strong orientational order of [bmim] and n-alcohol molecules near the interface, with [bmim] extending its butyl group into the alcohol phase while the alcohol has the OH group pointing into the ion liquid region, which is consistent with the recent sum-frequency-generation experiments. We found the interface to have a significant influence on the dynamics of ionic liquids and n-alcohols. The orientational autocorrelation functions illustrate that [bmim] rotate more freely near the interface than in the bulk, while the rotation of n-alcohol is hindered at the interface. Additionally, the time scale associated with the diffusion along the interfacial direction is found to be faster for [bmim] but slowed down for n-alcohols approaching the interface. We also calculate the dipole moment of n-alcohols as a function of the distance normal to the interface. We found that, even though methanol and 1-butanol have different dipole moments in bulk phase, they reach a similar value at the interface. This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. Pacific Northwest National Laboratory is a multiprogram national laboratory operated for the Department of Energy by Battelle. The calculations were carried out using computer resources provided by the

  20. A Study of Minority Group Student Access to Vocational-Technical Schools in the Boston and Springfield Metropolitan Areas.

    ERIC Educational Resources Information Center

    Massachusetts Advisory Council on Vocational-Technical Education, Boston.

    The express purpose of the study reported here is to examine whether minority group students (including female students) have equal access to vocational-technical schools. The study assessed whether or not such access, as measured through enrollment in vocational-technical school programs, currently exists. The kinds of information gathered and…

  1. Structural ordering at solid-liquid interfaces in Al-Sm system: A molecular-dynamics study

    DOE PAGESBeta

    Sun, Yang; Zhang, Feng; Ye, Zhuo; Ding, Zejun; Mendelev, Mikhail I.; Kramer, Matthew J.; Wang, Cai -Zhuang; Ho, Kai -Ming

    2016-07-12

    The structural ordering at solid-liquid interfaces far from equilibrium is studied with molecular dynamics simulations for the Al-Sm system. Using the van-Hove self-correlation function as the criterion to identify attachment/detachment events that occur at the interface, we are able to determine the time-dependent interface position, and characterize the detailed interfacial structure ordering surrounding the attached atoms. For the interface between an undercooled Al90Sm10 liquid and a metastable cubic structure, the solid induces the crystalline order of the cubic phase in the liquid layers, promoting the continuous growth of the crystal phase. When the same liquid is put in contact withmore » f.c.c. Al, Sm from the liquid can still attach to the solid interface despite its insolubility in the Al lattice. Non-f.c.c. order is revealed surrounding the attached Sm atoms. Lastly, we show that the local structure ordering at interface is highly correlated to solid packing and liquid ordering.« less

  2. A TEM Study of the Microstructure of Plasma-Sprayed YSZ Near Inter-splat Interfaces

    NASA Astrophysics Data System (ADS)

    Yang, Er-Juan; Luo, Xiao-Tao; Yang, Guan-Jun; Li, Cheng-Xin; Li, Chang-Jiu.

    2015-08-01

    The splat interface bonding state which changes heat transfer conditions and thus the cooling rate during splat cooling may influence the interface microstructure. In this paper, YSZ coating was deposited by atmospheric plasma spraying with substrate cooling during deposition. Subsequent characterization was implemented using high resolution transmission electron microscopy to examine the local microstructures near the interfaces at the bonded and unbonded zones. Selected area diffraction analyses of the splats across both the bonded interface and unbonded interface revealed that all bulk splats present a metastable tetragonal structure. Results showed that the size of columnar grains within a splat was significantly influenced by the interface bonding. At the unbonded region in the splat, large columnar grains form which can be attributed to poor thermal contact of melt to the underlying splat surface before its solidification. At the bonded zones, the splat presents a much fine columnar grain structure, which is attributed to good thermal contact of the melt to the underlying splat before solidification. Moreover, it is evident that the bonded interface region presents a distinct microstructure feature from the fine columnar grains suggesting the crystal defect of high density of dislocations at the interface.

  3. Study program for encapsulation materials interface for low-cost solar array

    NASA Technical Reports Server (NTRS)

    Kaelble, D. H.; Mansfeld, F. B.; Kendig, M.; Leung, C.

    1981-01-01

    The service integrity of the bonded interface in solar cell modules used in solar arrays is addressed. The development of AC impedance as a nondestructive evaluation (NDE) methodology for solar arrays is reported along with development of corrosion models and materials selection criteria for corrosion resistant interfaces.

  4. Two Case Studies in the Phonetics-Phonology Interface: Evidence from Turkish Voicing and Norwegian Coalescence

    ERIC Educational Resources Information Center

    Feizollahi, Zhaleh

    2010-01-01

    The phonetics-phonology interface has long been debated; some linguists argue for a modular approach (Keating 1984, Pierrehumbert 1990, Zsiga 1997, Cohn 1998), while others argue that there is no interface, and that phonetics and phonology are one and the same (Browman & Goldstein 1989-1992, Ohala 1990). Recent proposals by Gafos (2002), and…

  5. Study of organic-inorganic hetero-interfaces and electrical transport in semiconducting nanostructures

    NASA Astrophysics Data System (ADS)

    Wagner, Sean Robert

    As the electronics industry continues to evolve and move towards functional electronic devices with increasing complexity and functionality, it becomes important to explore materials outside the regime of conventional semiconductors. Organic semiconducting small molecules have received a large amount of attention due to their high degree of flexibility, the option to perform molecular synthesis to modify their electronic and magnetic properties, and their ability to organize into highly-ordered functionalized nanostructures and thin films. Being able to form complex nanostructures and thin films with molecular precision, while maintaining the ability to tune properties through modifications in the molecular chemistry could result in vast improvements in conventional device architectures. However, before this is realized, there still remains a significant lack of understanding regarding how these molecules interact with various substrate surfaces as well as their intermolecular interactions. The interplay between these interactions can produce drastic changes in the molecular orientation and ordering at the hetero-interface, which can affect the transport properties of the molecular thin film and ultimately modify the performance of the organic electronic device. This study first focuses on the growth dynamics, molecular ordering, and molecular orientation of metal phthalocyanine (MPc) molecules, particularly on Si, a substrate which is notoriously difficult to form an organized organic thin film on due to the surface dangling bonds. By deactivating these bonds, the formation of a highly ordered organic molecular thin film becomes possible. Combining scanning tunneling microscopy, scanning tunneling spectroscopy, low-energy electron diffraction, and density functional theory calculations, the growth evolution of MPc molecules ( M = Zn, Cu, Co) from the single molecule level to multilayered films on the deactivated Si(111)-B surface is investigated. Initial tests are

  6. Smart nanogels at the air/water interface: structural studies by neutron reflectivity.

    PubMed

    Zielińska, Katarzyna; Sun, Huihui; Campbell, Richard A; Zarbakhsh, Ali; Resmini, Marina

    2016-03-01

    The development of effective transdermal drug delivery systems based on nanosized polymers requires a better understanding of the behaviour of such nanomaterials at interfaces. N-Isopropylacrylamide-based nanogels synthesized with different percentages of N,N'-methylenebisacrylamide as cross-linker, ranging from 10 to 30%, were characterized at physiological temperature at the air/water interface, using neutron reflectivity (NR), with isotopic contrast variation, and surface tension measurements; this allowed us to resolve the adsorbed amount and the volume fraction of nanogels at the interface. A large conformational change for the nanogels results in strong deformations at the interface. As the percentage of cross-linker incorporated in the nanogels becomes higher, more rigid matrices are obtained, although less deformed, and the amount of adsorbed nanogels is increased. The data provide the first experimental evidence of structural changes of nanogels as a function of the degree of cross-linking at the air/water interface. PMID:26697736

  7. Space tug/shuttle interface compatibility study. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Shuttle interfaces required for space tug accommodation are primarily involved with supporting and servicing the tug during launch countdown, flight, and postlanding; deploying and retrieving the tug on orbit; and maintaining control over the tug when it is in or near the orbiter. Each of these interface areas was investigated to determine the best physical and operational method of accomplishing the required functions, with an overriding goal of establishing simple and flexible orbiter interface requirements suitable for tug, tug payloads, IUS and other cargo. It is concluded the orbiter payload accommodations and the MSFC baseline tug are generally interface compatible. Specific minor changes to tug and orbiter interfaces were identified to provide full compatibility. A system concept for supporting and deploying tug from orbiter is described.

  8. First-Principles Studies of Hydrogen Adsorption at Pd-SiO2 Interfaces

    PubMed Central

    Irokawa, Yoshihiro; Usami, Mamoru

    2015-01-01

    The interaction of hydrogen with Pd-SiO2 interfaces has been investigated for the first time using first-principles calculations based on density functional theory. The hydrogen-induced polarization at the Pd-SiO2 interfaces was evaluated using Pd-SiO2 interface supercells. As a result, the potential change induced by interfacial hydrogen atoms was not observed even for hydrogen concentration of ~1.3 × 1015 cm−2 at the Pd-SiO2 interface. This result implies that hydrogen does not create an electric double layer at the Pd-SiO2 interface but change the property of the SiO2 region, resulting in the hydrogen sensitivity of the devices. PMID:26110410

  9. Graphene-coated surface plasmon resonance interfaces for studying the interactions between bacteria and surfaces.

    PubMed

    Subramanian, Palaniappan; Barka-Bouaifel, Fatiha; Bouckaert, Julie; Yamakawa, Nao; Boukherroub, Rabah; Szunerits, Sabine

    2014-04-23

    A variety of physical and chemical parameters are of importance for adhesion of bacteria to surfaces. In the colonization of mammalian organisms for example, bacterial fimbriae and their adhesins not only seek particular glycan sequences exposed on diverse epithelial linings, they also enable the bacteria to overcome electrostatic repulsion exerted by their selected surfaces. In this work, we present a new technique based on simplified model systems for studying the adhesion strength of different Escherichia coli strains. For this purpose, gold-based surface plasmon resonance (SPR) interfaces were coated with thin films of reduced graphene oxide (rGO) through electrophoretic deposition. The rGO matrix was post-modified with polyethyleneimine (PEI), poly(sodium 4-styrenesulfonate) (PSS), mannose, and lactose through π-stacking and/or electrostatic interactions by simple immersion of the SPR interface into their respective aqueous solutions. The adhesion behaviors of one uropathogenic and two enterotoxigenic Escherichia coli clinical isolates, that each express structurally characterized fimbrial adhesins, were investigated. It was found that the UTI89 cystitis isolate that carries the mannose-binding FimH adhesin was most attracted to the PEI- and mannose-modified surfaces, whereas the att25 diarrhoeal strain with the N-acetylglucosamine-specific F17a-G adhesin disintegrated the lactose-modified rGO. The highly virulent 107/86 strain interacted strongly with the PSS-modified graphene oxide, in agreement with the polybasic surroundings of the ABH blood group-binding site of the FedF adhesin, and showed a linear SPR response in a concentration range between 1 × 10(2) and 1 × 10(9) cfu/mL. PMID:24433135

  10. Interface between platinum(111) and liquid isopropanol (2-propanol): A model for molecular dynamics studies

    NASA Astrophysics Data System (ADS)

    Tarmyshov, Konstantin B.; Müller-Plathe, Florian

    2007-02-01

    A molecular dynamics model and its parametrization procedure are devised and used to study adsorption of isopropanol on platinum(111) (Pt(111)) surface in unsaturated and oversaturated coverages regimes. Static and dynamic properties of the interface between Pt(111) and liquid isopropanol are also investigated. The magnitude of the adsorption energy at unsaturated level increases at higher coverages. At the oversaturated coverage (multilayer adsorption) the adsorption energy reduces, which coincides with findings by Panja et al. in their temperature-programed desorption experiment [Surf. Sci. 395, 248 (1998)]. The density analysis showed a strong packing of molecules at the interface followed by a depletion layer and then by an oscillating density profile up to 3nm. The distribution of individual atom types showed that the first adsorbed layer forms a hydrophobic methyl "brush." This brush then determines the distributions further from the surface. In the second layer methyl and methine groups are closer to the surface and followed by the hydroxyl groups; the third layer has exactly the inverted distribution. The alternating pattern extends up to about 2nm from the surface. The orientational structure of molecules as a function of distance of molecules is determined by the atom distribution and surprisingly does not depend on the electrostatic or chemical interactions of isopropanol with the metal surface. However, possible formation of hydrogen bonds in the first layer is notably influenced by these interactions. The surface-adsorbate interactions influence the mobility of isopropanol molecules only in the first layer. Mobility in the higher layers is independent of these interactions.

  11. Femtosecond studies of electron dynamics and structure at metal-molecular interfaces

    SciTech Connect

    Miller, Andre D.

    2002-07-15

    Femtosecond angle resolved two photon photoemission spectroscopy is used to study the electronic structure and electron dynamics at interfaces. At interfaces of thiolates chemisorbed on Ag(111), the adsorbate molecular electronic orbitals are observed to be nondispersive at low coverages and become dispersive at higher coverages. This is attributed to a phase transition of the layer. The molecules initially adsorb with their chains parallel to the surface. As the coverage is increased, the molecules order into a layer with the chains standing up from the surface. This closer packing results in a larger overlap between neighboring molecular orbitals and a dispersive electronic state. The lack of a change in the n=1 image potential state electron lifetimes as a function of chain length indicate that the electrons reside in the layer. The n=2 and 3 image potential state electron lifetimes decrease as the chain length is increased. This is attributed to the repulsive potential of the alkyl chains pushing the electron density into the sulfur portion of the layer. At a layer of acetonitrile molecules adsorbed on Ag(111), the image potential state electrons interact strongly with the adsorbate molecular dipoles. The dipoles rotate to solvate the electron, resulting in a decrease of the observed photoemitted electron kinetic energy as a function of time delay between population and photoemission. This is attributed to a change in the local work function resulting from the reorganization of the adsorbate layer molecules. For two layers of acetonitrile adsorbed on the Ag(111) substrate, dynamic electron localization is also observed.

  12. Adsorption of cationic polyacrylamide at the cellulose-liquid interface: a neutron reflectometry study.

    PubMed

    Su, Jielong; Garvey, Christopher J; Holt, Stephen; Tabor, Rico F; Winther-Jensen, Bjorn; Batchelor, Warren; Garnier, Gil

    2015-06-15

    The layer thickness and density of high molecular weight cationic polyacrylamide (CPAM) adsorbed at the cellulose-water interface was quantified by neutron reflectometry. The thickness of a full monolayer of CPAM of constant molecular weight (13 MD) but different charge densities, adsorbed with or without NaCl (10(-3) M), was studied. Thin cellulose films (40±7 Å) of roughness <10 Å were produced by spin coating a cellulose acetate-acetone solution and regenerating by alkaline hydrolysis. Film smoothness was greatly improved by controlling the concentration of cellulose acetate (0.13 wt%) and the hydrolysis time in sodium methoxide. The adsorption thickness of CPAM (40% charge 13 MD) at the solid-D2O interface was 43±4 Å on cellulose and 13±2 Å on silicon, an order of magnitude smaller than the CPAM radius of gyration. At constant molecular weight, the thickness of the CPAM layer adsorbed on cellulose increases with polymer charge density (10±1 Å at 5%). Addition of 10(-3) M NaCl decreased the thickness of CPAM layer already adsorbed on cellulose. However, the adsorption layer on cellulose of a CPAM solution equilibrated in 10(-3) M NaCl is much thicker (89±11 Å for 40% CPAM). For high molecular weight CPAMs adsorbed from solution under constant conditions, the adsorption layer can be varied by 1 order of magnitude via control of the variables affecting electrostatic intra- and inter-polymer chain interactions. PMID:25723785

  13. Air Conditioning and Refrigeration. Volume XXVI. 1975 Edition of Course of Study Outlines. Middlesex County Vocational and Technical High Schools and Middlesex County Adult Technical Schools.

    ERIC Educational Resources Information Center

    Capizzi, James

    The two courses of study described and outlined here are offered at Burr D. Coe Vocational and Technical High School in East Brunswick, New Jersey, for students wishing to prepare for a career in air conditioning and refrigeration. Section 1 deals with a 4-year high school course, Section 2 with a 1-year course for those who have completed high…

  14. Iranian nurses’ experience of essential technical competences in disaster response: A qualitative content analysis study

    PubMed Central

    Aliakbari, Fatemeh; Bahrami, Masoud; Aein, Fereshteh; Khankeh, Hamidreza

    2014-01-01

    Background: Today disasters are a part of many people's lives. Iran has a long history of disaster events and nurses are one of the most significant groups within the Iranian disaster relief operations, providing immediate and long-term care for those affected by the disaster. However, the technical competence of Iranian nurses and their training for this work has received little attention. This article presents the results of a study that aims to explore this context. Materials and Methods: A qualitative study was conducted using in-depth interviews to collect data from 30 nurses, who were deliberately selected from the health centers affiliated to the Isfahan University of Medical Sciences. Themes were identified using the conventional qualitative content analysis. The trustworthiness of the study was supported by considering the auditability, neutrality, consistency, and transferability. The study lasted from 2011 to 2012. Results: Data analysis undertaken for the qualitative study resulted in the identification of five main themes, which included: (1) Management competences, (2) ethical and legal competences, (3) team working, and (4) personal abilities and the specific technical competences presented in this report. Conclusions: This report presents an overview of the nursing technical capabilities required for Iranian nurses during disaster relief. It is argued that additional competencies are required for nurses who care in high-risk situations, including disasters. Nurses need to prepare themselves more effectively to be responsible and effective in nursing care. PMID:25558255

  15. Smart nanogels at the air/water interface: structural studies by neutron reflectivity

    NASA Astrophysics Data System (ADS)

    Zielińska, Katarzyna; Sun, Huihui; Campbell, Richard A.; Zarbakhsh, Ali; Resmini, Marina

    2016-02-01

    The development of effective transdermal drug delivery systems based on nanosized polymers requires a better understanding of the behaviour of such nanomaterials at interfaces. N-Isopropylacrylamide-based nanogels synthesized with different percentages of N,N'-methylenebisacrylamide as cross-linker, ranging from 10 to 30%, were characterized at physiological temperature at the air/water interface, using neutron reflectivity (NR), with isotopic contrast variation, and surface tension measurements; this allowed us to resolve the adsorbed amount and the volume fraction of nanogels at the interface. A large conformational change for the nanogels results in strong deformations at the interface. As the percentage of cross-linker incorporated in the nanogels becomes higher, more rigid matrices are obtained, although less deformed, and the amount of adsorbed nanogels is increased. The data provide the first experimental evidence of structural changes of nanogels as a function of the degree of cross-linking at the air/water interface.The development of effective transdermal drug delivery systems based on nanosized polymers requires a better understanding of the behaviour of such nanomaterials at interfaces. N-Isopropylacrylamide-based nanogels synthesized with different percentages of N,N'-methylenebisacrylamide as cross-linker, ranging from 10 to 30%, were characterized at physiological temperature at the air/water interface, using neutron reflectivity (NR), with isotopic contrast variation, and surface tension measurements; this allowed us to resolve the adsorbed amount and the volume fraction of nanogels at the interface. A large conformational change for the nanogels results in strong deformations at the interface. As the percentage of cross-linker incorporated in the nanogels becomes higher, more rigid matrices are obtained, although less deformed, and the amount of adsorbed nanogels is increased. The data provide the first experimental evidence of structural changes

  16. Atomistic studies of grain boundaries and heterophase interfaces in alloys and compounds. Final report, July 1987-August 1998

    SciTech Connect

    Vitek, Vaclav

    1998-08-01

    The overarching goal of the research supported by this grant was investigation of the structure and properties of interfaces in multicomponent systems by atomistic modeling. Initially, the research was devoted to studies of segregation to grain boundaries in binary disordered alloys. The next step was then studies of the structure and properties of grain boundaries in ordered compounds, specifically Ni3Al and NiAl, and grain boundary segregation in these compounds in the case of off-stoichiometry. Finally, the structure of Nb/sapphire interfaces, in particular the core configurations of the misfit dislocations, was studied.

  17. Urban water interfaces

    NASA Astrophysics Data System (ADS)

    Gessner, M. O.; Hinkelmann, R.; Nützmann, G.; Jekel, M.; Singer, G.; Lewandowski, J.; Nehls, T.; Barjenbruch, M.

    2014-06-01

    Urban water systems consist of large-scale technical systems and both natural and man-made water bodies. The technical systems are essential components of urban infrastructure for water collection, treatment, storage and distribution, as well as for wastewater and runoff collection and subsequent treatment. Urban aquatic ecosystems are typically subject to strong human influences, which impair the quality of surface and ground waters, often with far-reaching impacts on downstream aquatic ecosystems and water users. The various surface and subsurface water bodies in urban environments can be viewed as interconnected compartments that are also extensively intertwined with a range of technical compartments of the urban water system. As a result, urban water systems are characterized by fluxes of water, solutes, gases and energy between contrasting compartments of a technical, natural or hybrid nature. Referred to as urban water interfaces, boundaries between and within these compartments are often specific to urban water systems. Urban water interfaces are generally characterized by steep physical and biogeochemical gradients, which promote high reaction rates. We hypothesize that they act as key sites of processes and fluxes with notable effects on overall system behaviour. By their very nature, urban water interfaces are heterogeneous and dynamic. Therefore, they increase spatial heterogeneity in urban areas and are also expected to contribute notably to the temporal dynamics of urban water systems, which often involve non-linear interactions and feedback mechanisms. Processes at and fluxes across urban water interfaces are complex and less well understood than within well-defined, homogeneous compartments, requiring both empirical investigations and new modelling approaches at both the process and system level. We advocate an integrative conceptual framework of the urban water system that considers interfaces as a key component to improve our fundamental

  18. The High School Transcript Study: The 2000 High School Transcript Study User's Guide and Technical Report. NCES 2005-483

    ERIC Educational Resources Information Center

    Roey, Stephen; Caldwell, Nancy; Rust, Keith; Hicks, Lloyd; Lee, Janice; Perkins, Robert; Blumstein, Eyal; Brown, Janis

    2005-01-01

    This technical report documents the procedures used to collect and summarize data from the 2000 High School Transcript Study (HSTS 2000). Chapters in the report detail the sampling of schools and students (chapters 2 and 3), data collection procedures (chapter 4), data processing procedures (chapter 5), and weighting procedures (chapter 6).…

  19. Video-microscopic observation of ionic liquid/alcohol interface and the corresponding molecular simulation study

    NASA Astrophysics Data System (ADS)

    Zhu, Peixi

    This research is aimed at studying the ionic liquid/n-pentanol interface via video-microscopy and molecular dynamic simulations. Understanding the interfacial phenomena and interfacial transport between ionic liquids and other liquids is of interest to the development and application of ionic liquids in a number of areas. One such area is the biphasic hydroformylation of alkenes to obtain alcohol and aldehyde, in which case ionic liquid is the reaction medium where a catalyst resides. The dissolution of an ionic liquid into an alcohol was studied by microscopically observing and measuring the shrinking of a micropipette-produced droplet in real time. Although microscopic investigation of droplet dissolution has been studied before, no attempt had been made to measure the diffusion coefficient D of the droplet species in the surrounding medium. A key finding of this work is that the Epstein-Plesset mathematical model, which describes the dissolution of a droplet/bubble in another fluid medium, can be used to measure D. Other experimental studies of the ionic liquid/alcohol system include electrical conductivity and UV-visible spectroscopy measurements of solutions of 1-hexyl-3-methylimidazolium tetrafluoroborate in n-pentanol. Those experiments were done in order to understand the molecular state of the particular ionic liquid in n-pentanol, as well as obtaining the dissociation constant K of such weak electrolyte solution. The experimental results provide an entry to the assessment of ionic liquid interaction with n-pentanol at molecular scale. Subsequently, molecular dynamics simulation was implemented for the investigation of such interaction. The computation started with simulation of the bulk phase of 1-butyl-3-methylimidazolium tetrafluoroborate, an affine ionic liquid on which molecular simulations had already been reported. A generalized probability based on Fuoss approximation for the closest ion to a distinguished countercharge ion was developed. In

  20. A Model Study of Inclusions Deposition, Macroscopic Transport, and Dynamic Removal at Steel-Slag Interface for Different Tundish Designs

    NASA Astrophysics Data System (ADS)

    Chen, Chao; Ni, Peiyuan; Jonsson, Lage Tord Ingemar; Tilliander, Anders; Cheng, Guoguang; Jönsson, Pär Göran

    2016-06-01

    This paper presents computational fluid dynamics (CFD) simulation results of inclusions macroscopic transport as well as dynamic removal in tundishes. A novel treatment was implemented using the deposition velocity calculated by a revised unified Eulerian deposition model to replace the widely used Stokes rising velocity in the boundary conditions for inclusions removal at the steel-slag interface in tundishes. In this study, the dynamic removal for different size groups of inclusions at different steel-slag interfaces (smooth or rough) with different absorption conditions at the interface (partially or fully absorbed) in two tundish designs was studied. The results showed that the dynamic removal ratios were higher for larger inclusions than for smaller inclusions. Besides, the dynamic removal ratio was higher for rough interfaces than for smooth interfaces. On the other hand, regarding the cases when inclusions are partially or fully absorbed at a smooth steel-slag interface, the removal ratio values are proportional to the absorption proportion of inclusions at the steel-slag interface. Furthermore, the removal of inclusions in two tundish designs, i.e., with and without a weir and a dam were compared. Specifically, the tundish with a weir and a dam exhibited a better performance with respect to the removal of bigger inclusions (radii of 5, 7, and 9 μm) than that of the case without weir and dam. That was found to be due to the strong paralleling flow near the middle part of the top surface. However, the tundish without weir and dam showed a higher removal ratio of smaller inclusions (radius of 1 μm). The reason could be the presence of a paralleling flow near the inlet zone, where the inclusions deposition velocities were much higher than in other parts.

  1. A Model Study of Inclusions Deposition, Macroscopic Transport, and Dynamic Removal at Steel-Slag Interface for Different Tundish Designs

    NASA Astrophysics Data System (ADS)

    Chen, Chao; Ni, Peiyuan; Jonsson, Lage Tord Ingemar; Tilliander, Anders; Cheng, Guoguang; Jönsson, Pär Göran

    2016-03-01

    This paper presents computational fluid dynamics (CFD) simulation results of inclusions macroscopic transport as well as dynamic removal in tundishes. A novel treatment was implemented using the deposition velocity calculated by a revised unified Eulerian deposition model to replace the widely used Stokes rising velocity in the boundary conditions for inclusions removal at the steel-slag interface in tundishes. In this study, the dynamic removal for different size groups of inclusions at different steel-slag interfaces (smooth or rough) with different absorption conditions at the interface (partially or fully absorbed) in two tundish designs was studied. The results showed that the dynamic removal ratios were higher for larger inclusions than for smaller inclusions. Besides, the dynamic removal ratio was higher for rough interfaces than for smooth interfaces. On the other hand, regarding the cases when inclusions are partially or fully absorbed at a smooth steel-slag interface, the removal ratio values are proportional to the absorption proportion of inclusions at the steel-slag interface. Furthermore, the removal of inclusions in two tundish designs, i.e., with and without a weir and a dam were compared. Specifically, the tundish with a weir and a dam exhibited a better performance with respect to the removal of bigger inclusions (radii of 5, 7, and 9 μm) than that of the case without weir and dam. That was found to be due to the strong paralleling flow near the middle part of the top surface. However, the tundish without weir and dam showed a higher removal ratio of smaller inclusions (radius of 1 μm). The reason could be the presence of a paralleling flow near the inlet zone, where the inclusions deposition velocities were much higher than in other parts.

  2. Fluorescent DNA probes at liquid/liquid interfaces studied by surface second harmonic generation.

    PubMed

    Licari, Giuseppe; Brevet, Pierre-François; Vauthey, Eric

    2016-01-28

    The properties of a series of oxazole yellow dyes, including the dicationic YOPRO-1 and its homodimeric parent YOYO-1 and two monocationic dyes (YOSAC-1 and YOSAC-3), have been investigated at the dodecane/water interface using stationary and time-resolved surface second harmonic generation (SSHG) combined with quantum chemical calculations. Whereas YOYO-1 exists predominantly as a H-dimer in aqueous solution, the stationary SSHG spectra reveal that such dimers are not formed at the interface. No significant H-aggregation was observed with YOPRO-1, neither in solution nor at the interface. In the case of the monocationic YOSAC dyes, a distinct SSHG band due to H-aggregates was measured at the interface, whereas only weak aggregation was found in solution. These distinct aggregation behaviors can be explained by the different orientations of the dyes at the interface, as revealed from the analysis of polarization-resolved experiments, the doubly-charged dyes lying more flat on the interface than the singly charged ones. Although YOYO-1 and YOPRO-1 do not form H-dimer/aggregates at the interface, time-resolved SSHG measurements point to the occurrence of intra- and intermolecular interactions, respectively, which inhibit the ultrafast non-radiative decay of the excited dyes via large amplitude motion, and lead to a nanosecond excited-state lifetime. The distinct behavior evidenced here for YOYO-1 and YOSAC dyes points to their potential use as fluorescent or SHG interfacial probes. PMID:26740332

  3. Nuclear magnetic resonance studies of granular flows: Technical progress report, quarter ending 09/30/93

    SciTech Connect

    Not Available

    1993-10-27

    This Technical Progress Report for the quarter ending 09/30/93 describes work on two tasks which are part of nuclear magnetic resonance studies of granular flows. (1) Research has been directed toward improving concentration measurements under reasonably fast conditions. (2) The process continues of obtaining comprehensive velocity, concentration, and diffusion information at several angular velocities of the cylinder for seeds (mustard, sesame, and sunflower seeds) flowing in a half-filled cylinder.

  4. Effects of different seat cushions on interface pressure distribution: a pilot study.

    PubMed

    Lee, Sang-Heon; Park, Ji-Su; Jung, Bong-Keun; Lee, Sung-A

    2016-01-01

    [Purpose] The purpose of this study was to evaluate pressure redistribution on the supporting area of healthy volunteers when using different cushions. [Subjects and Methods] Twenty healthy individuals ranging in age from 19-23 years old and 20 older adults age 60 or above participated in the study. All participants lived in urban communities in South Korea. Group differences according to gender, age, and cushion types were analyzed with one-way analysis of variance and post-hoc analysis. [Results] Statistically significant differences in peak pressure and mean pressure were identified between age, gender, and cushion types. Peak pressure and mean pressure were higher on firm surfaces and on the air cushion than other cushion types. The pressure ratio was lower when an air cushion was used in the buttock area and was higher when it was used under the thighs compared to that in other conditions. [Conclusion] This study showed that interface pressure can be distributed differently depending on what cushions are used. Therefore, when using seat cushions, individuals should seek advice to help them choose the appropriate cushion for their needs. PMID:26957763

  5. Effects of different seat cushions on interface pressure distribution: a pilot study

    PubMed Central

    Lee, Sang-Heon; Park, Ji-Su; Jung, Bong-Keun; Lee, Sung-A

    2016-01-01

    [Purpose] The purpose of this study was to evaluate pressure redistribution on the supporting area of healthy volunteers when using different cushions. [Subjects and Methods] Twenty healthy individuals ranging in age from 19–23 years old and 20 older adults age 60 or above participated in the study. All participants lived in urban communities in South Korea. Group differences according to gender, age, and cushion types were analyzed with one-way analysis of variance and post-hoc analysis. [Results] Statistically significant differences in peak pressure and mean pressure were identified between age, gender, and cushion types. Peak pressure and mean pressure were higher on firm surfaces and on the air cushion than other cushion types. The pressure ratio was lower when an air cushion was used in the buttock area and was higher when it was used under the thighs compared to that in other conditions. [Conclusion] This study showed that interface pressure can be distributed differently depending on what cushions are used. Therefore, when using seat cushions, individuals should seek advice to help them choose the appropriate cushion for their needs. PMID:26957763

  6. 1991 Pacific Northwest Loads and Resources Study, Technical Appendix: Volume 1.

    SciTech Connect

    United States. Bonneville Power Administration.

    1992-03-01

    This publication provides detailed documentation of the load forecast scenarios and assumptions used in preparing BPA's 1991 Pacific Northwest Loads and Resources Study (the Study). This is one of two technical appendices to the Study; the other appendix details the utility-specific loads and resources used in the Study. The load forecasts and assumption were developed jointly by Bonneville Power Administration (BPA) and Northwest Power Planning Council (Council) staff. This forecast is also used in the Council's 1991 Northwest Conservation and Electric Power Plan (1991 Plan).

  7. Analysis of E-Mail Produced by Middle School Students with Disabilities Using Accessible Interfaces: An Exploratory Study

    ERIC Educational Resources Information Center

    Sohlberg, McKay Moore; Todis, Bonnie; Fickas, Stephen; Ehlhardt, Laurie

    2011-01-01

    The goal of this exploratory study was to investigate electronic communication as a potential method to enhance social communication in a range of students with disabilities. This study investigated the usability of an adapted e-mail interface, TeenMail, for 11 middle school students with significant learning and communication impairments who…

  8. Earth Observatory Satellite system definition study. Report 6: Space shuttle interfaces/utilization

    NASA Technical Reports Server (NTRS)

    1974-01-01

    An analysis was conducted to determine the compatibility of the Earth Observatory Satellite (EOS) with the space shuttle. The mechanical interfaces and provisions required for a launch or retrieval of the EOS by the space shuttle are summarized. The space shuttle flight support equipment required for the operation is defined. Diagrams of the space shuttle in various configurations are provised to show the mission capability with the EOS. The subjects considered are as follows: (1) structural and mechanical interfaces, (2) spacecraft retention and deployment, (3) spacecraft retrieval, (4) electrical interfaces, (5) payload shuttle operations, (6) shuttle mode cost analysis, (7) shuttle orbit trades, and (8) safety considerations.

  9. Space Station Furnace Facility Core. Requirements definition and conceptual design study. Volume 2: Technical report. Appendix 6: Technical summary reports

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The Space Station Furnace Facility (SSFF) is a modular facility for materials research in the microgravity environment of the Space Station Freedom (SSF). The SSFF is designed for crystal growth and solidification research in the fields of electronic and photonic materials, metals and alloys, and glasses and ceramics and will allow for experimental determination of the role of gravitational forces in the solidification process. The facility will provide a capability for basic scientific research and will evaluate the commercial viability of low-gravity processing of selected technologically important materials. The facility is designed to support a complement of furnace modules as outlined in the Science Capabilities Requirements Document (SCRD). The SSFF is a three rack facility that provides the functions, interfaces, and equipment necessary for the processing of the furnaces and consists of two main parts: the SSFF Core Rack and the two Experiment Racks. The facility is designed to accommodate two experimenter-provided furnace modules housed within the two experiment racks, and is designed to operate these two furnace modules simultaneously. The SCRD specifies a wide range of furnace requirements and serves as the basis for the SSFF conceptual design. SSFF will support automated processing during the man-tended operations and is also designed for crew interface during the permanently manned configuration. The facility is modular in design and facilitates changes as required, so the SSFF is adept to modifications, maintenance, reconfiguration, and technology evolution.

  10. Evaluation of a new approach for modelling the screw-bone interface in a locking plate fixation: a corroboration study.

    PubMed

    Moazen, Mehran; Mak, Jonathan H; Jones, Alison C; Jin, Zhongmin; Wilcox, Ruth K; Tsiridis, Eleftherios

    2013-07-01

    Computational modelling of the screw-bone interface in fracture fixation constructs is challenging. While incorporating screw threads would be a more realistic representation of the physics, this approach can be computationally expensive. Several studies have instead suppressed the threads and modelled the screw shaft with fixed conditions assumed at the screw-bone interface. This study assessed the sensitivity of the computational results to modelling approaches at the screw-bone interface. A new approach for modelling this interface was proposed, and it was tested on two locking screw designs in a diaphyseal bridge plating configuration. Computational models of locked plating and far cortical locking constructs were generated and compared to in vitro models described in prior literature to corroborate the outcomes. The new approach led to closer agreement between the computational and the experimental stiffness data, while the fixed approach led to overestimation of the stiffness predictions. Using the new approach, the pattern of load distribution and the magnitude of the axial forces, experienced by each screw, were compared between the locked plating and far cortical locking constructs. The computational models suggested that under more severe loading conditions, far cortical locking screws might be under higher risk of screw pull-out than the locking screws. The proposed approach for modelling the screw-bone interface can be applied to any fixation involved application of screws. PMID:23636756

  11. The Effective Use of Scientific and Technical Information in Industrial and Non-Profit Settings: A Study of Managerial Interventions.

    ERIC Educational Resources Information Center

    Shapero, Albert; And Others

    A study conducted in a non profit research and development organization and the technical development department of a profit corporation was designed to develop and implement interventions that would modify the information-communication behaviors of the technical professionals in these organizations, and to measure and analyze the effects of the…

  12. Are We "There" Yet? the Treatment of Gender and Feminism in Technical, Business, and Workplace Writing Studies

    ERIC Educational Resources Information Center

    White, Kate; Rumsey, Suzanne Kesler; Amidon, Stevens

    2016-01-01

    This article reexamines the treatment of gender and feminism in technical, business, and workplace writing studies--areas in which the three of us teach. Surprisingly, the published discourse of our field seems to implicitly minimize the gendered nature of business and technical writing workplaces and classrooms. To understand this apparent lack…

  13. Electronic Structure of C60/Phthalocyanine/ITO Interfaces Studied using Soft X-ray Spectroscopies

    SciTech Connect

    Cho, S.; Piper, L; DeMasi, A; Preston, A; Smith, K; Chauhan, K; Sullivan, P; Hatton, R; Jones, T

    2010-01-01

    The interface electronic structure of a bilayer heterojunction of C{sub 60} and three different phthalocyanines grown on indium tin oxide (ITO) has been studied using synchrotron radiation-excited photoelectron spectroscopy. The energy difference between the highest occupied molecular orbital level of the phthalocyanine (donor) layer and the lowest unoccupied molecular orbital level of the C{sub 60} (acceptor) layer (E{sub HOMO}{sup D} - E{sub LUMO}{sup A}) was determined. The E{sub HOMO}{sup D} - E{sub LUMO}{sup A} of a heterojunction with boron subphthalocyanine chloride (SubPc) was found to be much larger than those of copper phthalocyanine (CuPc) and chloro-aluminum phthalocyanine (ClAlPc). This observation is discussed in terms of the difference of the ionization energy of each donor material. Additionally, we have studied the molecular orientation of the phthalocyanine films on ITO using angle-dependent X-ray absorption spectroscopy. We found that the SubPc films showed significant disorder compared to the CuPc and ClAlPc films and also found that E{sub HOMO}{sup D} - E{sub LUMO}{sup A} varied with the orientation of the ClAlPc molecules relative to the ITO substrate. This orientation could be controlled by varying the ClAlPc deposition rate.

  14. Wildland-Urban Interface Fires and Socioeconomic Conditions: A Case Study of a Northwestern Patagonia City

    NASA Astrophysics Data System (ADS)

    de Torres Curth, Monica; Biscayart, Carolina; Ghermandi, Luciana; Pfister, Gabriela

    2012-04-01

    In many regions of the world, fires are primarily of anthropogenic origin. In northwestern Patagonia, the number of fires is not correlated with meteorological variables, but is concentrated in urban areas. This study was conducted in the wildland-urban interface (WUI) area of San Carlos de Bariloche (Patagonia, Argentina), within the Nahuel Huapi National Park. WUI fires are particularly problematic because, besides people and goods, they represent a danger to protected areas. We studied the relationship between fire records and socioeconomic indicators within the WUI of San Carlos de Bariloche. We conducted a Multiple Correspondence Factorial Analysis and an Ascendant Hierarchical Classification of the city neighborhoods. The results show that the neighborhoods in Bariloche can be divided into three classes: High Socioeconomic Fire Risk neighborhoods, including neighborhoods with the highest fire rates, where people have low instruction level, high levels of unsatisfied basic needs and high unemployment levels; Low Socioeconomic Fire Risk neighborhoods, that groups neighborhoods which present the opposite characterization, and Moderate Socioeconomic Fire Risk neighborhoods, which are more heterogeneous. Once neighborhoods were classified, a Socioeconomic Fire Risk map was generated, supplementing the existing WUI Fire Danger map. Our results emphasize the relevance of socioeconomic variables to fire policies.

  15. Dynamic modeling efforts for system interface studies for nuclear hydrogen production.

    SciTech Connect

    Vilim, R. B.; Nuclear Engineering Division

    2007-08-15

    System interface studies require not only identifying economically optimal equipment configurations, which involves studying mainly full power steady-state operation, but also assessing the operability of a design during load change and startup and assessing safety-related behavior during upset conditions. This latter task is performed with a dynamic simulation code. This report reviews the requirements of such a code. It considers the types of transients that will need to be simulated, the phenomena that will be present, the models best suited for representing the phenomena, and the type of numerical solution scheme for solving the models to obtain the dynamic response of the combined nuclear-hydrogen plant. Useful insight into plant transient behavior prior to running a dynamics code is obtained by some simple methods that take into account component time constants and energy capacitances. Methods for determining reactor stability, plant startup time, and temperature response during load change, and tripping of the reactor are described. Some preliminary results are presented.

  16. In situ study of the initiation of hydrogen bubbles at the aluminium metal/oxide interface

    NASA Astrophysics Data System (ADS)

    Xie, De-Gang; Wang, Zhang-Jie; Sun, Jun; Li, Ju; Ma, Evan; Shan, Zhi-Wei

    2015-09-01

    The presence of excess hydrogen at the interface between a metal substrate and a protective oxide can cause blistering and spallation of the scale. However, it remains unclear how nanoscale bubbles manage to reach the critical size in the first place. Here, we perform in situ environmental transmission electron microscopy experiments of the aluminium metal/oxide interface under hydrogen exposure. It is found that once the interface is weakened by hydrogen segregation, surface diffusion of Al atoms initiates the formation of faceted cavities on the metal side, driven by Wulff reconstruction. The morphology and growth rate of these cavities are highly sensitive to the crystallographic orientation of the aluminium substrate. Once the cavities grow to a critical size, the internal gas pressure can become great enough to blister the oxide layer. Our findings have implications for understanding hydrogen damage of interfaces.

  17. Ab initio study on the dynamics of furfural at the liquid-solid interfaces

    NASA Astrophysics Data System (ADS)

    Dang, Hongli; Xue, Wenhua; Shields, Darwin; Liu, Yingdi; Jentoft, Friederike; Resasco, Daniel; Wang, Sanwu

    2013-03-01

    Catalytic biomass conversion sometimes occurs at the liquid-solid interfaces. We report ab initio molecular dynamics simulations at finite temperatures for the catalytic reactions involving furfural at the water-Pd and water-Cu interfaces. We found that, during the dynamic process, the furan ring of furfural prefers to be parallel to the Pd surface and the aldehyde group tends to be away from the Pd surface. On the other hand, at the water-Cu(111) interface, furfural prefers to be tilted to the Cu surface while the aldehyde group is bonded to the surface. In both cases, interaction of liquid water and furfural is identified. The difference of dynamic process of furfural at the two interfaces suggests different catalytic reaction mechanisms for the conversion of furfural, consistent with the experimental investigations. Supported by DOE (DE-SC0004600). Simulations and calculations were performed on XSED's and NERSC's supercomputers

  18. In situ study of the initiation of hydrogen bubbles at the aluminium metal/oxide interface.

    PubMed

    Xie, De-Gang; Wang, Zhang-Jie; Sun, Jun; Li, Ju; Ma, Evan; Shan, Zhi-Wei

    2015-09-01

    The presence of excess hydrogen at the interface between a metal substrate and a protective oxide can cause blistering and spallation of the scale. However, it remains unclear how nanoscale bubbles manage to reach the critical size in the first place. Here, we perform in situ environmental transmission electron microscopy experiments of the aluminium metal/oxide interface under hydrogen exposure. It is found that once the interface is weakened by hydrogen segregation, surface diffusion of Al atoms initiates the formation of faceted cavities on the metal side, driven by Wulff reconstruction. The morphology and growth rate of these cavities are highly sensitive to the crystallographic orientation of the aluminium substrate. Once the cavities grow to a critical size, the internal gas pressure can become great enough to blister the oxide layer. Our findings have implications for understanding hydrogen damage of interfaces. PMID:26121306

  19. Relational Study of Technical Education in Scotland and Nigeria for Sustainable Skill Development

    ERIC Educational Resources Information Center

    Umunadi, E. Kennedy

    2014-01-01

    This paper was designed to look at technical education curriculum and mode of implementation in Scotland in order to adopt the advantageous attributes of the Scottish technical education in Nigeria. The paper x-rayed the staff perceptions of technical education and its roles in Scotland; history of technical education before the advent of British…

  20. Instrument constraints and interface specifications. Earth Observatory Satellite system definition study (EOS)

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The equipment specifications for the thematic mapper and high resolution pointable imager for use on the Earth Observatory Satellite (EOS) are presented. The interface requirements of the systems are defined. The interface requirements are extracted from the equipment specifications and are intended as a summary to be used by the system and spacecraft designer. The appropriate documentation from which the specifications of the equipment are established are identified.

  1. A theoretical study of the sum frequency vibrational spectroscopy of the carbon tetrachloride/water interface

    NASA Astrophysics Data System (ADS)

    Green, Anthony J.; Perry, Angela; Moore, Preston B.; Space, Brian

    2012-03-01

    Theoretical approximations to the sum frequency vibrational spectroscopy (SFVS) of the carbon tetrachloride/water interface are constructed using the quantum-corrected time correlation functions (TCF) to aid in interpretation of experimental data and to predict novel vibrational modes. Instantaneous normal mode (INM) methods are used to characterize the observed modes leading to the TCF signal, thus providing molecular resolution of the vibrational lineshapes. Detailed comparisons of the theoretical signals are made with those obtained experimentally and show excellent agreement for the spectral peaks in the O-H stretching region of water. An intermolecular mode, unique to the interface, at 848 cm-1 is also identifiable, similar to the one seen for the water/vapor interface. INM analysis reveals the resonance is due to a wagging mode (hindered rotation) that was previously identified (Perry et al 2005 J. Chem. Phys. 123 144705) as localized on a single water molecule with both hydrogens displaced normal to the interface—generally it is found that the symmetry breaking at the interface leads to hindered translations and rotations at hydrophilic/hydrophobic interfaces that assume finite vibrational frequencies due to anchoring at the aqueous interface. Additionally, examination of the real and imaginary parts of the theoretical SFVS spectra reveal the spectroscopic species attributed the resonances and possible subspecies in the O-H region; these results are consistent with extant experimental data and associated analysis.

  2. VISTA (Vertical Integration of Science, Technology, and Applications) user interface software study

    SciTech Connect

    Chin, G.

    1990-04-01

    The Vertical Integration of Science, Technology, and Applications (VISTA) project is an initiative to employ modern information and communications technology for rapid and effective application of basic research results by end users. Developed by the Pacific Northwest Laboratory, VISTA's purpose is to develop and deploy information systems (software or software/hardware products) to broad segments of various markets. Inherent in these products would be mechanisms for accessing PNL-resident information about the problem. A goal of VISTA is to incorporate existing, commercially available user interface technology into the VISTA UIMS. Commercial systems are generally more complete, reliable, and cost-effective than software developed in-house. The objective of this report is to examine the current state of commercial user interface software and discuss the implications of selections thereof. This report begins by describing the functionality of the user interface as it applies to users and application developers. Next, a reference model is presented defining the various operational software layers of a graphical user interface. The main body follows which examines current user interface technology by sampling a number of commercial systems. Both the window system and user interface toolkit markets are surveyed. A summary of the current technology concludes this report. 15 refs., 3 figs., 1 tab.

  3. Surface enhanced Raman spectroscopic studies of the metal-semiconductor interface in organic field effect transistors

    NASA Astrophysics Data System (ADS)

    Adil, Danish; Guha, Suchi

    2012-02-01

    The performance of organic field-effect transistors (FETs) largely depends on the nature of interfaces of dissimilar materials. Metal-semiconductor interfaces, in particular, play a critical role in the charge injection process. Here, Raman spectroscopy is used to investigate the nature of the Au-semiconductor interface in pentacene based FETs. A large enhancement in the Raman intensity (SERS) is observed from the pentacene film under the Au layer. The enhancement is evidence of a nano-scale roughness in the morphology of the interface, which is further confirmed by electron microscopy images. The morphology of the interface is investigated by SERS as a function of the pentacene layer thickness and the Au layer thickness. The Raman spectra are found to be extremely sensitive in detecting small changes in the morphology of the interface in the sub-nanometer range. Changes in the Raman spectra are further tracked after biasing and ageing the devices. Evolution of these Raman spectra is correlated with degradation in device performance. Finally, FETs based on other donor-acceptor semiconductors are probed by Raman scattering and contrasted with those of the pentacene-based devices.

  4. STM study of the superconducting proximity effect at 60 mK: influence of interface transparency.

    NASA Astrophysics Data System (ADS)

    Courtois, H.; Gupta, A. K.; Cretinon, L.; Moussy, N.; Pannetier, B.

    2002-03-01

    Proximity effect of a superconductor on a normal metal has a renewed interest recently. The effort, so far, has been to make the N-S interface as transparent and clean as possible to enhance the proximity effects. Here, we investigate the influence of interface transparency on the superconducting proximity effect of niobium on gold by probing the local density of states (DOS) at the surface of a thin gold layer deposited on a thick niobium film. This is achieved by measuring the tunneling spectra with a home-made STM operating in a upside-down dilution fridge at 60mK temperature footnote[1]N. Moussy, H. Courtois, and B. Pannetier, Rev. Sci. Instrum. 72, 128 (2001).. We observe BCS like spectra for the transparent interface since the gold layer thickness is much smaller than the coherence length. The interface transparency is adjusted by in situ argon etching of the Nb surface before depositing the gold layer. As a result of this semi-transparent interface, the BCS-like spectra evolve into a depression in the DOS near the Fermi energy (E_F) with a reduced energy scale as compared to the superconducting gap (Δ) together with some remnant features near Δ. We discuss the dependence of these two features on the interface transparency and the gold layer thickness and its possible implications.

  5. Adsorption and solvation of ethanol at the water liquid-vapor interface: a molecular dynamics study

    NASA Technical Reports Server (NTRS)

    Wilson, M. A.; Pohorille, A.

    1997-01-01

    The free energy profiles of methanol and ethanol at the water liquid-vapor interface at 310K were calculated using molecular dynamics computer simulations. Both alcohols exhibit a pronounced free energy minimum at the interface and, therefore, have positive adsorption at this interface. The surface excess was computed from the Gibbs adsorption isotherm and was found to be in good agreement with experimental results. Neither compound exhibits a free energy barrier between the bulk and the surface adsorbed state. Scattering calculations of ethanol molecules from a gas phase thermal distribution indicate that the mass accommodation coefficient is 0.98, and the molecules become thermalized within 10 ps of striking the interface. It was determined that the formation of the solvation structure around the ethanol molecule at the interface is not the rate-determining step in its uptake into water droplets. The motion of an ethanol molecule in a water lamella was followed for 30 ns. The time evolution of the probability distribution of finding an ethanol molecule that was initially located at the interface is very well described by the diffusion equation on the free energy surface.

  6. Review of Technical Studies in the United States in Support of Burnup Credit Regulatory Guidance

    SciTech Connect

    Wagner, John C; Parks, Cecil V; Mueller, Don; Gauld, Ian C

    2010-01-01

    Taking credit for the reduction in reactivity associated with fuel depletion can enable more cost-effective, higher-density storage, transport, disposal, and reprocessing of spent nuclear fuel (SNF) while maintaining sufficient subcritical margin to establish an adequate safety basis. Consequently, there continues to be considerable interest in the United States (U.S.), as well as internationally, in the increased use of burnup credit in SNF operations, particularly related to storage, transport, and disposal of commercial SNF. This interest has motivated numerous technical studies related to the application of burnup credit, both domestically and internationally, as well as the design of SNF storage, transport and disposal systems that rely on burnup credit for maintaining subcriticality. Responding to industry requests and needs, the U.S. Nuclear Regulatory Commission (NRC) initiated a burnup credit research program in 1999, with support from the Oak Ridge National Laboratory (ORNL), to develop regulatory guidance and the supporting technical bases for allowing and expanding the use of burnup credit in pressurized-water reactor SNF storage and transport applications. Although this NRC research program has not been continuous since its inception, considerable progress has been achieved in many key areas in terms of increased understanding of relevant phenomena and issues, availability of relevant information and data, and subsequently updated regulatory guidance for expanded use of burnup credit. This paper reviews technical studies performed by ORNL for the U.S. NRC burnup credit research program. Examples of topics include reactivity effects associated with reactor operating characteristics, fuel assembly characteristics, burnable absorbers, control rods, spatial burnup distributions, cooling time, and assembly misloading; methods and data for validation of isotopic composition predictions; methods and data for validation of criticality calculations; and

  7. Fatigue creep damage at the cement-bone interface: an experimental and a micro-mechanical finite element study

    PubMed Central

    Waanders, Daan; Janssen, Dennis; Miller, Mark A.; Mann, Kenneth A.; Verdonschot, Nico

    2009-01-01

    The goal of this study was to quantify the micromechanics of the cement-bone interface under tensile fatigue loading using finite element analysis (FEA) and to understand the underlying mechanisms that play a role in the fatigue behavior of this interface. Laboratory cement-bone specimens were subjected to a tensile fatigue load, while local displacements and crack growth on the specimen's surface were monitored. FEA models were created from these specimens based upon micro-computed tomography data. To accurately model interfacial gaps at the interface between the bone and cement, a custom-written erosion algorithm was applied to the bone model. A fatigue load was simulated in the FEA models while monitoring the local displacements and crack propagation. The results showed the FEA models were able to capture the general experimental creep damage behavior and creep stages of the interface. Consistent with the experiments, the majority of the deformation took place at the contact interface. Additionally, the FEA models predicted fatigue crack patterns similar to experimental findings. Experimental surface cracks correlated moderately with FEA surface cracks (r2=0.43), but did not correlate with the simulated crack volume fraction (r2=0.06). Although there was no relationship between experimental surface cracks and experimental creep damage displacement (r2=0.07), there was a strong relationship between the FEA crack volume fraction and the FEA creep damage displacement (r2=0.76). This study shows the additional value of FEA of the cement-bone interface relative to experimental studies and can therefore be used to optimize its mechanical properties. PMID:19682690

  8. Structure and charging of hydrophobic material/water interfaces studied by phase-sensitive sum-frequency vibrational spectroscopy

    PubMed Central

    Tian, C. S.; Shen, Y. R.

    2009-01-01

    We have studied the hydrophobic water/octadecyltrichlorosilane (OTS) interface by using the phase-sensitive sum-frequency vibrational spectroscopy (PS-SFVS), and we obtained detailed structural information of the interface at the molecular level. Excess ions emerging at the interface were detected by changes of the surface vibrational spectrum induced by the surface field created by the excess ions. Both hydronium (H3O+) and hydroxide (OH−) ions were found to adsorb at the interface, and so did other negative ions such as Cl−. By varying the ion concentrations in the bulk water, their adsorption isotherms were measured. It was seen that among the three, OH− has the highest adsorption energy, and H3O+ has the lowest; OH− also has the highest saturation coverage, and Cl− has the lowest. The result shows that even the neat water/OTS interface is not neutral, but charged with OH− ions. The result also explains the surprising observation that the isoelectric point appeared at ∼3.0 when HCl was used to decrease the pH starting from neat water. PMID:19706483

  9. Simulation study on factors influencing the entrainment behavior of liquid steel as bubbles pass through the steel/slag interface

    NASA Astrophysics Data System (ADS)

    Li, Xiang; Bao, Yan-ping; Wang, Min; Lin, Lu

    2016-05-01

    In this study, a water/silicone oil interface was used to simulate the steel/slag interface in a converter. A high-speed camera was used to record the entrainment process of droplets when air bubbles were passed through the water/silicone oil interface. Motion parameters of the bubbles and droplets were obtained using particle kinematic analysis software, and the entrainment rate of the droplets was calculated. It was found that the entrainment rate decreased from 29.5% to 0 when the viscosity of the silicone oil was increased from 60 mPa·s to 820 mPa·s in the case of bubbles with a 5 mm equivalent diameter passing through the water/silicone oil interface. The results indicate that increasing the viscosity of the silicone oil is conducive to reducing the entrainment rate. The entrainment rate increased from 0 to 136.3% in the case of silicone oil with a viscosity of 60 mPa·s when the equivalent diameter of the bubbles was increased from 3 mm to 7 mm. We therefore conclude that small bubbles are also conductive to reducing the entrainment rate. The force analysis results for the water column indicate that the entrainment rate of droplets is affected by the velocity of the bubble passing through the water/silicone oil interface and that the entrainment rate decreases with the bubble velocity.

  10. Electrical and Optical Studies of Interfaces Between Electrolyte Solutions and Semiconductors or Metals

    NASA Astrophysics Data System (ADS)

    Dollard, William Joseph

    In Part I, experimental studies of the time-resolved bandgap emission of CdSe are used to probe the attributes required in a theoretical model for the carrier dynamics of semiconductor electrodes. The experimental results show that the details of bulk recombination, the effects of self-absorption and the influence of the space charge field are quite important factors for the carrier dynamics. Simulation results show that the detailed kinetics of the interfacial recombination can also have important consequences for the carrier relaxation. Five different silane compounds are used to chemically modify the CdSe interface and change the surface recombination velocity. A general trend of increasing recombination velocity with increasing ionization potential of the silane is observed. In Part II, the desirability of resolving the activities of solutions of electrolytes into the individual ionic contributions is discussed. In this work we follow an approach pioneered by Parsons involving measurement in the jet (Kenrick) cell of outer-potential differences between solutions of the same electrolyte in two solvents. These potential differences provide the "real" free energies of transfer of individual ions which, in turn, differ from the usual Gibbs energies of transfer by the work required to transfer the ion through the dipolar layers at the two solvent-gas interfaces. The new extrathermodynamic assumption is now that the difference between the surface potentials of the two solvents can be estimated. One objective of this work was to improve the reliability of "real" free energy of transfer measurements, which are experimentally demanding, to within ca. 0.5 kJ mol^{ -1} in order to match typical uncertainties in Gibbs transfer energies of electrolytes. This goal was met, in most instances, by careful evaluation of experimental parameters (particularly jet pressure) influencing the measurement of outer-potential differences. A major improvement over previous measurements

  11. Study of flow at the interface of a porous medium using particle image velocimetry

    NASA Astrophysics Data System (ADS)

    Shams Saryazdi, Masoud

    This thesis reports the results of an experimental study of the flow at the interface of a fibrous porous medium and a freely flowing fluid. The model for the porous medium was a square array of parallel rods, and arrays with three different solid volume fractions were tested; namely 2.5%, 5.2%, and 10%. The flow adjacent to the porous medium was a shear flow perpendicular to the interface. It was created by generating circular Couette flow in a narrow channel outside the porous medium. Comprehensive velocity measurements were made inside and outside the various porous media using a PIV system that was developed for the experiment. An adverse pressure gradient in the streamwise direction was found to exist between the rods for the media with solid volume fractions of 5.2% and 10%. However no such pressure gradient was found for the 2.5% medium. The fluid motion corresponding to the adverse pressure gradients inside the medium was circulatory. The slip coefficient proposed by Beavers and Joseph was found directly by measuring the local velocity near the boundary of the porous medium. The slip coefficient for the media tested was found to be approximately 3. Comparisons show that Brinkman's equation in its original form (with the same viscosity inside the porous medium mu* and outside mu) did not produce results that matched the measured velocity field. Furthermore, Brinkman's equation did not produce results that matched the experimental velocity fields using any value of the viscosity ratio, mu*/mu. The measurements show that the slip velocity is small, and that Brinkman's equation with mu*/mu ≈ 9 predicts slip velocities quite well. The shear penetration length decreases as the solid volume fraction increases, and for a porous medium with a solid volume fraction of around 10%, the penetration length is smaller than all length scales of the medium. Therefore, for the higher solid volume fractions tested, shear penetration is practically negligible. Penetration of

  12. EPR and rheological study of hybrid interfaces in gold-clay-epoxy nanocomposites.

    PubMed

    Angelov, Verislav; Velichkova, Hristiana; Ivanov, Evgeni; Kotsilkova, Rumiana; Delville, Marie-Hélène; Cangiotti, Michela; Fattori, Alberto; Ottaviani, Maria Francesca

    2014-11-11

    obtained from this study is applicable to understand the role of interfaces in ternary nanocomposites with different combinations of nanofillers. PMID:25330464

  13. [Time-resolved optical studies of charge relaxation and charge transfer at electrode interfaces

    SciTech Connect

    Not Available

    1992-12-31

    Key components were identified in a quantitative model of carrier relaxation in semiconductor electrodes: nonlinear aspects of nonradiative and radiative recombination, effect of space charge field on carrier dynamics, self-absorption effects in direct gas semiconductors, and influence of surface state population kinetics on charge carrier recombination. For CdSe, the first three are operative (no direct proof of the last one). A realistic kinetic model for carrier recombination in the bulk of CdSe was used which includes important nonlinear effects, both radiative and nonradiative. The change in interfacial recombination velocity with the chemical nature of the sinterface was studied (n-CdSe/silane interfaces). Temperature effect (278 to 328 K) on fluorescence decay of n-CdSe in contact with 0.5 M KOH was found to be weak. An analytical solution was obtained for time-resolved fluoresence from electrodes under potential bias, and is being tested. Fluorescence work on a different material, CdS, indicate different recombination kinetics; this material was used to directly pump an optical transition of a surface state.

  14. [Time-resolved optical studies of charge relaxation and charge transfer at electrode interfaces

    SciTech Connect

    Not Available

    1992-01-01

    Key components were identified in a quantitative model of carrier relaxation in semiconductor electrodes: nonlinear aspects of nonradiative and radiative recombination, effect of space charge field on carrier dynamics, self-absorption effects in direct gas semiconductors, and influence of surface state population kinetics on charge carrier recombination. For CdSe, the first three are operative (no direct proof of the last one). A realistic kinetic model for carrier recombination in the bulk of CdSe was used which includes important nonlinear effects, both radiative and nonradiative. The change in interfacial recombination velocity with the chemical nature of the sinterface was studied (n-CdSe/silane interfaces). Temperature effect (278 to 328 K) on fluorescence decay of n-CdSe in contact with 0.5 M KOH was found to be weak. An analytical solution was obtained for time-resolved fluoresence from electrodes under potential bias, and is being tested. Fluorescence work on a different material, CdS, indicate different recombination kinetics; this material was used to directly pump an optical transition of a surface state.

  15. Innovative Power Wheelchair Control Interface: A Proof-of-Concept Study.

    PubMed

    Winkler, Sandra L; Romero, Sergio; Prather, Emily; Ramroop, Marisa; Slaibe, Emmy; Christensen, Matthew

    2016-01-01

    Some people without independent mobility are candidates for powered mobility but are unable to use a traditional power wheelchair joystick. This proof-of-concept study tested and further developed an innovative method of driving power wheelchairs for people whose impairments prevent them from operating commercial wheelchair controls. Our concept, Self-referenced Personal Orthotic Omni-purpose Control Interface (SPOOCI), is distinguished by referencing the control sensor not to the wheelchair frame but instead to the adjacent proximal lower-extremity segment via a custom-formed orthosis. Using a descriptive case-series design, we compared the pre-post functional power wheelchair driving skill data of 4 participants, measured by the Power Mobility Program, using descriptive analyses. The intervention consisted of standard-care power wheelchair training during 12 outpatient occupational or physical therapy sessions. All 4 participants who completed the 12-wk intervention improved their functional power wheelchair driving skills using SPOOCI, but only 3 were deemed safe to continue with power wheelchair driving. PMID:26943118

  16. Using minimal human-computer interfaces for studying the interactive development of social awareness

    PubMed Central

    Froese, Tom; Iizuka, Hiroyuki; Ikegami, Takashi

    2014-01-01

    According to the enactive approach to cognitive science, perception is essentially a skillful engagement with the world. Learning how to engage via a human-computer interface (HCI) can therefore be taken as an instance of developing a new mode of experiencing. Similarly, social perception is theorized to be primarily constituted by skillful engagement between people, which implies that it is possible to investigate the origins and development of social awareness using multi-user HCIs. We analyzed the trial-by-trial objective and subjective changes in sociality that took place during a perceptual crossing experiment in which embodied interaction between pairs of adults was mediated over a minimalist haptic HCI. Since that study required participants to implicitly relearn how to mutually engage so as to perceive each other's presence, we hypothesized that there would be indications that the initial developmental stages of social awareness were recapitulated. Preliminary results reveal that, despite the lack of explicit feedback about task performance, there was a trend for the clarity of social awareness to increase over time. We discuss the methodological challenges involved in evaluating whether this trend was characterized by distinct developmental stages of objective behavior and subjective experience. PMID:25309490

  17. Study of interface interactions in ZnO/Mesoporous silica nanocomposite

    NASA Astrophysics Data System (ADS)

    Reddy A, R. C.; Babu K, Sowri; Ch, Sujatha; Reddy K, V. G.

    2012-02-01

    The Photoluminescence (PL) properties of ZnO/Mesoporous silica (MPS) nanocomposite annealed under different temperatures were studied. A broad PL band at 395 nm has been observed in all samples and analysis was made by using Gaussian fitting. As the temperature increased, emission bands were blue shifted and the relative intensity ratio of the oxygen vacancies at ZnO-SiO2 interface to the oxygen vacancies in inner ZnO crystallites was increased. The emission peaks at 363 nm and 384 nm are attributed to the near band edge emission (NBE) and to the phonon replica emission. At 550C the exciton confinement effect disappears due to the large amount of surface effects. The influence of porosity of host media on Si-O-Zn cross linking bonds was also investigated. ZnO nanoparticles were loaded into nanocrystalline silica (NCS) and silica gel (SG). The surface area increases monotonously from NCS to MPS through SG. Si-O-Zn cross linking bonds were almost absent in the sample prepared with NCS. It exhibits NBE emission at 360 nm which was found to be absent in other samples prepared with SG and MPS. It was also found that the emission intensity of the samples decreases with aging. This is due to diffusion of oxygen atoms from the atmosphere to interior of the sample.

  18. Molecular Dynamics Study of the Electrical Double Layer at Silver Chloride Electrolyte Interfaces

    SciTech Connect

    Zarzycki, Piotr P.; Kerisit, Sebastien N.; Rosso, Kevin M.

    2010-05-20

    Molecular dynamics simulations of the electrical double layer at AgCl/aqueous electrolyte (KCl) interfaces are presented, accompanied by a new force field and properties of bulk AgCl computed using planewave density functional theory. Long dynamics simulations were performed to estimate ion adsorption free energies at the AgCl surface. The simulations demonstrate formation of a bilayer hydration sheet composed of two sublayers of water molecules interconnected by hydrogen bonds. Potassium ions prefer to form an inner-sphere complex, whereas chloride ions prefer outer-sphere complexes. The adsorbed ions/water layers form a relatively rigid structure within the range of ionic strength considered, which confirms the applicability of the Helmholtz model in a high concentration regime. Profiles of the charge density, electric field and electrostatic potential across the simulation cell revealed that oscillations of water molecules govern these quantities. The electrostatic potential generated only by the electrolyte ions was used to study the quasi-Nernstian response of the silver chloride surface to the variation in the ionic strength.

  19. A Study of Various Feature Extraction Methods on a Motor Imagery Based Brain Computer Interface System

    PubMed Central

    Resalat, Seyed Navid; Saba, Valiallah

    2016-01-01

    Introduction: Brain Computer Interface (BCI) systems based on Movement Imagination (MI) are widely used in recent decades. Separate feature extraction methods are employed in the MI data sets and classified in Virtual Reality (VR) environments for real-time applications. Methods: This study applied wide variety of features on the recorded data using Linear Discriminant Analysis (LDA) classifier to select the best feature sets in the offline mode. The data set was recorded in 3-class tasks of the left hand, the right hand, and the foot motor imagery. Results: The experimental results showed that Auto-Regressive (AR), Mean Absolute Value (MAV), and Band Power (BP) features have higher accuracy values,75% more than those for the other features. Discussion: These features were selected for the designed real-time navigation. The corresponding results revealed the subject-specific nature of the MI-based BCI system; however, the Power Spectral Density (PSD) based α-BP feature had the highest averaged accuracy. PMID:27303595

  20. Study of dithiol monolayer as the interface for controlled deposition of gold nanoparticles

    SciTech Connect

    Cichomski, M.; Tomaszewska, E.; Kosla, K.; Kozlowski, W.; Grobelny, J.

    2011-03-15

    Self-assembled monolayer of dithiol molecules, deposited on polycrystalline Au (111), prepared at room atmosphere, was studied using scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). Dithiols were used as interface, which chemically bonds to the deposited gold nanoparticles through strong covalent bonds. The size and size distribution of the deposited nanoparticles were measured using dynamic light scattering (DLS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The AFM results showed that nanoparticles are immobilized and stable during scanning procedure and do not contaminate the AFM tip. The size of monodisperse nanoparticles obtained from the DLS measurements is slightly higher than that obtained from the AFM and SEM measurements. This is due to the fact that the DLS measures the hydrodynamic radius, dependent on the protective chemical layer on nanoparticles. - Research Highlights: {yields} Dithiols molecules create chemically bounded layers on a Au (111) surface. {yields} Gold nanoparticles can be chemically bounded to a self-assembled monolayer. {yields} Nanoparticles are stable during AFM probe interactions.

  1. Microarray study of temperature-dependent sensitivity and selectivity of metal/oxide sensing interfaces

    NASA Astrophysics Data System (ADS)

    Tiffany, Jason; Cavicchi, Richard E.; Semancik, Stephen

    2001-02-01

    Conductometric gas microsensors offer the benefits of ppm-level sensitivity, real-time data, simple interfacing to electronics hardware, and low power consumption. The type of device we have been exploring consists of a sensor film deposited on a "microhotplate"- a 100 micron platform with built-in heating (to activate reactions on the sensing surface) and thermometry. We have been using combinatorial studies of 36-element arrays to characterize the relationship between sensor film composition, operating temperature, and response, as measured by the device's sensitivity and selectivity. Gases that have been tested on these arrays include methanol, ethanol, dichloromethane, propane, methane, acetone, benzene, hydrogen, and carbon monoxide, and are of interest in the management of environmental waste sites. These experiments compare tin oxide films modified by catalyst overlayers, and ultrathin metal seed layers. The seed layers are used as part of a chemical vapor deposition process that uses each array element's microheater to activate the deposition of SnO2, and control its microstructure. Low coverage (20 Ê) catalytic metals (Pd, Cu, Cr, In, Au) are deposited on the oxides by masked evaporation or sputtering. This presentation demonstrates the value of an array-based approach for developing film processing methods, measuring performance characteristics, and establishing reproducibility. It also illustrates how temperature-dependent response data for varied metal/oxide compositions can be used to tailor a microsensor array for a given application.

  2. A Metaproteomic Approach to Study Human-Microbial Ecosystems at the Mucosal Luminal Interface

    PubMed Central

    Li, Xiaoxiao; LeBlanc, James; Truong, Allison; Vuthoori, Ravi; Chen, Sharon S.; Lustgarten, Jonathan L.; Roth, Bennett; Allard, Jeff; Ippoliti, Andrew; Presley, Laura L.; Borneman, James; Bigbee, William L.; Gopalakrishnan, Vanathi; Graeber, Thomas G.; Elashoff, David

    2011-01-01

    Aberrant interactions between the host and the intestinal bacteria are thought to contribute to the pathogenesis of many digestive diseases. However, studying the complex ecosystem at the human mucosal-luminal interface (MLI) is challenging and requires an integrative systems biology approach. Therefore, we developed a novel method integrating lavage sampling of the human mucosal surface, high-throughput proteomics, and a unique suite of bioinformatic and statistical analyses. Shotgun proteomic analysis of secreted proteins recovered from the MLI confirmed the presence of both human and bacterial components. To profile the MLI metaproteome, we collected 205 mucosal lavage samples from 38 healthy subjects, and subjected them to high-throughput proteomics. The spectral data were subjected to a rigorous data processing pipeline to optimize suitability for quantitation and analysis, and then were evaluated using a set of biostatistical tools. Compared to the mucosal transcriptome, the MLI metaproteome was enriched for extracellular proteins involved in response to stimulus and immune system processes. Analysis of the metaproteome revealed significant individual-related as well as anatomic region-related (biogeographic) features. Quantitative shotgun proteomics established the identity and confirmed the biogeographic association of 49 proteins (including 3 functional protein networks) demarcating the proximal and distal colon. This robust and integrated proteomic approach is thus effective for identifying functional features of the human mucosal ecosystem, and a fresh understanding of the basic biology and disease processes at the MLI. PMID:22132074

  3. A computational study of interfaces in WC-Co cemented carbides

    NASA Astrophysics Data System (ADS)

    Petisme, Martin V. G.; Johansson, Sven A. E.; Wahnström, Göran

    2015-06-01

    Interfaces in WC-Co cemented carbides have been investigated using the density functional theory (DFT). Six different model WC/WC grain boundaries are considered, together with the corresponding WC surfaces and WC/Co phase boundaries. The contribution to the grain boundary energies arising from misfit is estimated using an analytical bond order potential (ABOP) and the effect of magnetism is investigated using spinpolarized and non-spinpolarized calculations. A systematic study of adsorption of Co to WC surfaces, Co segregation to WC/WC grain boundaries and Co substitution at WC/Co phase boundaries has been carried out. Adsorption of Co to most WC surfaces is predicted, and result in a monolayer coverage of Co and sometimes a mixed Co/W or Co/W monolayer. The WC surfaces will become prewetted with Co as soon as the atoms become mobile at finite temperatures. Co substitutional segregation is predicted to all model WC/WC grain boundaries in 0.5 monolayer proportion. The segregation of Co to grain boundaries stabilizes the continuous skeleton network of hard WC grains in cemented carbides. Using the obtained interfacial energies, the wetting and the driving force for cobalt grain boundary infiltration are discussed. A dependence on the wetting efficiency on the carbon chemical potential is predicted, which could be an explanation for the better wetting observed experimentally under W-rich conditions.

  4. Innovative Power Wheelchair Control Interface: A Proof-of-Concept Study

    PubMed Central

    Romero, Sergio; Prather, Emily; Ramroop, Marisa; Slaibe, Emmy; Christensen, Matthew

    2016-01-01

    Some people without independent mobility are candidates for powered mobility but are unable to use a traditional power wheelchair joystick. This proof-of-concept study tested and further developed an innovative method of driving power wheelchairs for people whose impairments prevent them from operating commercial wheelchair controls. Our concept, Self-referenced Personal Orthotic Omni-purpose Control Interface (SPOOCI), is distinguished by referencing the control sensor not to the wheelchair frame but instead to the adjacent proximal lower-extremity segment via a custom-formed orthosis. Using a descriptive case-series design, we compared the pre–post functional power wheelchair driving skill data of 4 participants, measured by the Power Mobility Program, using descriptive analyses. The intervention consisted of standard-care power wheelchair training during 12 outpatient occupational or physical therapy sessions. All 4 participants who completed the 12-wk intervention improved their functional power wheelchair driving skills using SPOOCI, but only 3 were deemed safe to continue with power wheelchair driving. PMID:26943118

  5. Shuttle/Agena study. Volume 2, part 2: Agena tug configurations, Shuttle/Agena interface, performance, safety, cost

    NASA Technical Reports Server (NTRS)

    1972-01-01

    An evaluation of the compatibility of the space shuttle and Agena rocket vehicle was conducted. The Agena space tug configuration design is described in terms of the total vehicle system as well as the individual subsystems and major assemblies and components. The complete interface between the Agena space tug and the space shuttle orbiter is defined for in-flight and ground operations. The derivation and design of an evolutionary stage is also presented. This vehicle conforms to the same guidelines and interface requirements as the Agena space tug. Performance data developed for both vehicles for each of the three study baseline missions are included.

  6. Combining situated Cognitive Engineering with a novel testing method in a case study comparing two infusion pump interfaces.

    PubMed

    Schnittker, R; Schmettow, M; Verhoeven, F; Schraagen, J M C

    2016-07-01

    We validated the usability of a new infusion pump interface designed with a situated Cognitive Engineering approach by comparing it to a reference interface using a novel testing method employing repeated measurements and process measures, in addition to traditional outcome measures. The sample consisted of 25 nurses who performed eight critical tasks three times. Performance measures consisted of number and type of errors, deviations from a pre-established normative path solution, task completion times, number of keystrokes, mental effort and preferences in use. Results showed that interaction with the new interface resulted in 18% fewer errors, 90% fewer normative path deviations, 42% lower task completion times, 40% fewer keystrokes, 39% lower mental effort and 76% more subjective preferences in use. These outcomes suggest that within the scope of this case study, combining the situated Cognitive Engineering approach with a novel testing method addresses various shortcomings of earlier testing methods. PMID:26995032

  7. XPS study of the Al/SiO2 interface viewed from the SiO2 side

    NASA Technical Reports Server (NTRS)

    Hecht, M. H.; Grunthaner, F. J.; Maserjian, J.

    1984-01-01

    The first nondestructive measurement of the chemical and physical characteristics of the interface between bulk SiO2 and thick aluminum films is presented. Both X-ray photoelectron spectroscopy (XPS) and electrical measurements of unannealed resistively evaporated Al films on thermal SiO2 indicate an atomically abrupt interface. Postmetallization annealing (PMA) at 450 C induces reduction of the SiO2 by the aluminum, resulting in the layer ordering SiO2/Al2O3/Si/Al. The XPS measurement is performed from the SiO2 side after removal of the Si substrate after etching with XeF2 gas and thinning of the SiO2 layer with HF:ETOH. This represents a powerful new approach to the study of metal-insulator and other interfaces.

  8. Human-machine interface (HMI) report for 241-SY-101 data acquisition [and control] system (DACS) upgrade study

    SciTech Connect

    Truitt, R.W.

    1997-10-22

    This report provides an independent evaluation of information for a Windows based Human Machine Interface (HMI) to replace the existing DOS based Iconics HMI currently used in the Data Acquisition and Control System (DACS) used at Tank 241-SY-101. A fundamental reason for this evaluation is because of the difficulty of maintaining the system with obsolete, unsupported software. The DACS uses a software operator interface (Genesis for DOS HMI) that is no longer supported by its manufacturer, Iconics. In addition to its obsolescence, it is complex and difficult to train additional personnel on. The FY 1997 budget allocated $40K for phase 1 of a software/hardware upgrade that would have allowed the old DOS based system to be replaced by a current Windows based system. Unfortunately, budget constraints during FY 1997 has prompted deferral of the upgrade. The upgrade needs to be performed at the earliest possible time, before other failures render the system useless. Once completed, the upgrade could alleviate other concerns: spare pump software may be able to be incorporated into the same software as the existing pump, thereby eliminating the parallel path dilemma; and the newer, less complex software should expedite training of future personnel, and in the process, require that less technical time be required to maintain the system.

  9. How family carers engage with technical health procedures in the home: a grounded theory study

    PubMed Central

    McDonald, Janet; McKinlay, Eileen; Keeling, Sally; Levack, William

    2015-01-01

    Objectives To explore the experiences of family carers who manage technical health procedures at home and describe their learning process. Design A qualitative study using grounded theory. Participants New Zealand family carers (21 women, 5 men) who managed technical health procedures such as enteral feeding, peritoneal dialysis, tracheostomy care, a central venous line or urinary catheter. In addition, 15 health professionals involved in teaching carers were interviewed. Methods Semistructured interviews were coded soon after completion and preliminary analysis influenced subsequent interviews. Additional data were compared with existing material and as analysis proceeded, initial codes were grouped into higher order concepts until a core concept was described. Interviewing continued until no new ideas emerged and concepts were well defined. Results The response of carers to the role of managing technical health procedures in the home is presented in terms of five dispositions: (1) Embracing care, (2) Resisting, (3) Reluctant acceptance, (4) Relinquishing and (5) Being overwhelmed. These dispositions were not static and carers commonly changed between them. Embracing care included cognitive understanding of the purpose and benefits of a procedure; accepting a ‘technical’ solution; practical management; and an emotional response. Accepting embrace is primarily motivated by perceived benefits for the recipient. It may also be driven by a lack of alternatives. Resisting or reluctant acceptance results from a lack of understanding about the procedure or willingness to manage it. Carers need adequate support to avoid becoming overwhelmed, and there are times when it is appropriate to encourage them to relinquish care for the sake of their own needs. Conclusions The concept of embracing care encourages health professionals to extend their attention beyond simply the practical aspects of technical procedures to assessing and addressing carers’ emotional and

  10. A Study of a Direct Interface of the Novice User To a Complex Batch Processed Computer Application.

    ERIC Educational Resources Information Center

    Link, Albert D.

    A research study investigated the validity of directly interfacing an uninitiated user with a complex, computerized batch processing system via a conversational, interactive language. A control group conducted mediated searches of the Educational Resources Information Center's (ERIC) files by consulting with an information specialist. Members of…

  11. A Case Study of the Usability Testing of the University of South Florida's Virtual Library Interface Design.

    ERIC Educational Resources Information Center

    Allen, Maryellen

    2002-01-01

    Discussion of usability testing of Web interfaces for virtual libraries focuses on a usability study conducted at the University of South Florida. Highlights include testing instruments; discrepancies between actual performance and perceived performance; and the need to use plainer language and less jargon. (LRW)

  12. Technical specification for the Sandia Management Restructure Study Team (MRST) Prototype Information System

    SciTech Connect

    Wyatt, T.R.; Hall, R.C.; Davis, L.T.; Klamerus, E.J.; Thurston, I.

    1992-01-01

    This document contains implementation details for the Sandia Management Restructure Study Team (MRST) Prototype Information System, which resides on a Sun SPARC II workstation employing the INGRES RDBMS. The INGRES/Windows 4GL application editor was used to define the components of the two user applications which comprise the system. These specifications together with the MRST information model and corresponding database definition constitute the MRST Prototype Information System technical specification and implementation description presented herein. The MRST Prototype Information System represents a completed software product which has been presented to the Management Restructure Study Team to support the management restructing processes at Sandia National Laboratories.

  13. FRET study of G-quadruplex forming fluorescent oligonucleotide probes at the lipid monolayer interface

    NASA Astrophysics Data System (ADS)

    Swiatkowska, Angelika; Kosman, Joanna; Juskowiak, Bernard

    2016-01-01

    Spectral properties and G-quadruplex folding ability of fluorescent oligonucleotide probes at the cationic dioctadecyldimethylammonium bromide (DODAB) monolayer interface are reported. Two oligonucleotides, a 19-mer bearing thrombin binding aptamer sequence and a 21-mer with human telomeric sequence, were end-labeled with fluorescent groups (FAM and TAMRA) to give FRET probes F19T and F21T, respectively. The probes exhibited abilities to fold into a quadruplex structure and to bind metal cations (Na+ and K+). Fluorescence spectra of G-quadruplex FRET probes at the monolayer interface are reported for the first time. Investigations included film balance measurements (π-A isotherms) and fluorescence spectra recording using a fiber optic accessory interfaced with a spectrofluorimeter. The effect of the presence of DODAB monolayer, metal cations and the surface pressure of monolayer on spectral behavior of FRET probes were examined. Adsorption of probe at the cationic monolayer interface resulted in the FRET signal enhancement even in the absence of metal cations. Variation in the monolayer surface pressure exerted rather modest effect on the spectral properties of probes. The fluorescence energy transfer efficiency of monolayer adsorbed probes increased significantly in the presence of sodium or potassium ion in subphase, which indicated that the probes retained their cation binding properties when adsorbed at the monolayer interface.

  14. Interface structure and mechanics between graphene and metal substrates: a first-principles study

    NASA Astrophysics Data System (ADS)

    Xu, Zhiping; Buehler, Markus J.

    2010-12-01

    Graphene is a fascinating material not only for technological applications, but also as a test bed for fundamental insights into condensed matter physics due to its unique two-dimensional structure. One of the most intriguing issues is the understanding of the properties of graphene and various substrate materials. In particular, the interfaces between graphene and metal substrates are of critical importance in applications of graphene in integrated electronics, as thermal materials, and in electromechanical devices. Here we investigate the structure and mechanical interactions at a graphene-metal interface through density functional theory (DFT)-based calculations. We focus on copper (111) and nickel (111) surfaces adhered to a monolayer of graphene, and find that their cohesive energy, strength and electronic structure correlate directly with their atomic geometry. Due to the strong coupling between open d-orbitals, the nickel-graphene interface has a much stronger cohesive energy with graphene than copper. We also find that the interface cohesive energy profile features a well-and-shoulder shape that cannot be captured by simple pair-wise models such as the Lennard-Jones potential. Our results provide a detailed understanding of the interfacial properties of graphene-metal systems, and help to predict the performance of graphene-based nanoelectronics and nanocomposites. The availability of structural and energetic data of graphene-metal interfaces could also be useful for the development of empirical force fields for molecular dynamics simulations.

  15. Wildfire risk in the wildland-urban interface: A simulation study in northwestern Wisconsin

    USGS Publications Warehouse

    Massada, Avi Bar; Radeloff, Volker C.; Stewart, Susan I.; Hawbaker, Todd J.

    2009-01-01

    The rapid growth of housing in and near the wildland–urban interface (WUI) increases wildfirerisk to lives and structures. To reduce fire risk, it is necessary to identify WUI housing areas that are more susceptible to wildfire. This is challenging, because wildfire patterns depend on fire behavior and spread, which in turn depend on ignition locations, weather conditions, the spatial arrangement of fuels, and topography. The goal of our study was to assess wildfirerisk to a 60,000 ha WUI area in northwesternWisconsin while accounting for all of these factors. We conducted 6000 simulations with two dynamic fire models: Fire Area Simulator (FARSITE) and Minimum Travel Time (MTT) in order to map the spatial pattern of burn probabilities. Simulations were run under normal and extreme weather conditions to assess the effect of weather on fire spread, burn probability, and risk to structures. The resulting burn probability maps were intersected with maps of structure locations and land cover types. The simulations revealed clear hotspots of wildfire activity and a large range of wildfirerisk to structures in the study area. As expected, the extreme weather conditions yielded higher burn probabilities over the entire landscape, as well as to different land cover classes and individual structures. Moreover, the spatial pattern of risk was significantly different between extreme and normal weather conditions. The results highlight the fact that extreme weather conditions not only produce higher fire risk than normal weather conditions, but also change the fine-scale locations of high risk areas in the landscape, which is of great importance for fire management in WUI areas. In addition, the choice of weather data may limit the potential for comparisons of risk maps for different areas and for extrapolating risk maps to future scenarios where weather conditions are unknown. Our approach to modeling wildfirerisk to structures can aid fire risk reduction management

  16. Ultrafast optical studies of surface reaction processes at semiconductor interfaces. Progress report

    SciTech Connect

    Miller, R.J.D.

    1994-10-01

    The DOE funded research has focused on the development of novel non-linear optical methods for the in situ study of surface reaction dynamics. In particular, the work has concentrated on interfacial charge transfer processes as this is the simplest of all surface reactions, i.e., no bonds are broken and the reaction is derived from nuclear repolarization. Interfacial charge transfer forms the basis for a number of important solar energy conversion strategies. In these studies, semiconductor liquid junctions provide a convenient system in which the interfacial charge transfer can be optically initiated. The all-optical approach necessitates that the dynamics of the charge transfer event itself be put in the proper context of the operating photophysical processes at the surface. There are at least four dynamical processes that are coupled in determining the overall rate of electron flux across the interface. In the limit that interfacial charge transfer approaches strong coupling, the time scale for transport of even field accelerated carriers within the space charge region becomes comparable to the charge transfer dynamics. The transport component needs to be convolved to probes of the carrier population at the surface. The other two dynamical processes, carrier thermalization and surface state trapping, determine the states which ultimately serve as the donor levels to the solution acceptor distribution. In terms of the hot carrier model, these latter two processes compete with direct unthermalized charge transfer. There is a fifth dynamical process which also needs consideration: the solvent modes that are coupled to the reaction coordinate. Ultimately, the dynamics of solvent relaxation determine the upper limit to the charge transfer process. Different optical techniques have been developed to follow all the above dynamical processes in which a real time view of charge transfer dynamics at semiconductor surfaces is emerging. These results are discussed here.

  17. 1994 Pacific Northwest Loads and Resources Study, Technical Appendix: Volume 1.

    SciTech Connect

    United States. Bonneville Power Administration.

    1994-12-01

    The 1994 Pacific Northwest Loads and Resources Study establishes the Bonneville Power Administration`s (BPA) planning basis for supplying electricity t6 BPA customers. The Loads and Resources Study is presented in two documents: (1) this technical appendix detailing loads and resources for each major Pacific Northwest generating utility; and (2) a summary of Federal system and Pacific Northwest region loads and resources. This analysis updates the 1993 Pacific Northwest Loads and Resources Study Technical Appendix published in December 1993. This technical appendix provides utility specific information that BPA uses in its long-range planning. It incorporates the following for each utility: (1) electrical demand-firm loads; (2) generating resources; and (3) contracts both inside and outside the region. This document should be used in combination with the 1994 Pacific Northwest Loads and Resources Study, published in December 1994, because much of the information in that document is not duplicated here. This BPA planning document incorporates Pacific Northwest generating resources and the 1994 medium load forecast prepared by BPA. Each utility`s forecasted future firm loads are subtracted from its existing resources to determine whether it will be surplus or deficit. If a utility`s resources are greater than loads in any particular year or month, there is a surplus of energy and/or capacity, which the utility can sell to increase revenues. Conversely, if its firm loads exceed available resources, there is a deficit of energy and/or capacity, and additional conservation, contract purchases, or generating resources will be needed to meet the utility`s load.

  18. Milk whey proteins and xanthan gum interactions in solution and at the air-water interface: a rheokinetic study.

    PubMed

    Perez, Adrián A; Sánchez, Cecilio Carrera; Patino, Juan M Rodríguez; Rubiolo, Amelia C; Santiago, Liliana G

    2010-11-01

    In this contribution, we present experimental information about the effect of xanthan gum (XG) on the adsorption behaviour of two milk whey protein samples (MWP), beta-lactoglobulin (beta-LG) and whey protein concentrate (WPC), at the air-water interface. The MWP concentration studied corresponded to the protein bulk concentration which is able to saturate the air-water interface (1.0 wt%). Temperature, pH and ionic strength of aqueous systems were kept constant at 20 degrees C, pH 7 and 0.05 M, respectively, while the XG bulk concentration varied in the range 0.00-0.25 wt%. Biopolymer interactions in solution were analyzed by extrinsic fluorescence spectroscopy using 1-anilino-8-naphtalene sulphonic acid (ANS) as a protein fluorescence probe. Interfacial biopolymer interactions were evaluated by dynamic tensiometry and surface dilatational rheology. Adsorption behaviour was discussed from a rheokinetic point of view in terms of molecular diffusion, penetration and conformational rearrangement of adsorbed protein residues at the air-water interface. Differences in the interaction magnitude, both in solution and at the interface vicinity, and in the adsorption rheokinetic parameters were observed in MWP/XG mixed systems depending on the protein type (beta-LG or WPC) and biopolymer relative concentration. beta-LG adsorption in XG presence could be promoted by mechanisms based on biopolymer segregative interactions and thermodynamic incompatibility in the interface vicinity, resulting in better surface and viscoelastic properties. The same mechanism could be responsible of WPC interfacial adsorption in the presence of XG. The interfacial functionality of WPC was improved by the synergistic interactions with XG, although WPC chemical complexity might complicate the elucidation of molecular events that govern adsorption dynamics of WPC/XG mixed systems at the air-water interface. PMID:20692133

  19. The Interface between Gd and Monolayer MoS2: A First-Principles Study

    PubMed Central

    Zhang, Xuejing; Mi, Wenbo; Wang, Xiaocha; Cheng, Yingchun; Schwingenschlögl, Udo

    2014-01-01

    We analyze the electronic structure of interfaces between two-, four- and six-layer Gd(0001) and monolayer MoS2 by first-principles calculations. Strong chemical bonds shift the Fermi energy of MoS2 upwards into the conduction band. At the surface and interface the Gd f states shift to lower energy and new surface/interface Gd d states appear at the Fermi energy, which are strongly hybridized with the Mo 4d states and thus lead to a high spin-polarization (ferromagnetically ordered Mo magnetic moments of 0.15 μB). Gd therefore is an interesting candidate for spin injection into monolayer MoS2. PMID:25482498

  20. Micropipes and voids at β¨SiC/Si(100) interfaces: an electron microscopy study

    NASA Astrophysics Data System (ADS)

    Scholz, R.; Gösele, U.; Niemann, E.; Wischmeyer, F.

    The microstructure of β-SiC/Si(100) interfaces generated by carbonization and subsequent growth in a chemical vapor deposition (CVD) reactor was investigated by transmission electron microscopy (TEM). Differently prepared cross section and planar specimens allowed a detailed characterization of interface defects. Besides pyramidal voids, which were frequently reported to appear at SiC/Si interfaces within the substrate, recently discovered micropipes are of special interest. Both kinds of defects form by outdiffusion of silicon during the carbonization process. In contrast to voids. which initially remain empty, micropipes develop by simultaneous ingrowth of SiC. The area densities of micropipes were found to be orders of magnitude higher than those of voids. Micropipe formation may be due to a high density of SiC nuclei preexisting on the substrate surfaces after pretreatments. The simultaneous development of voids and micropipes is discussed on the basis of results obtained from a short-time carbonization experiment.

  1. Computational Study of the Richtmyer-Meshkov Instability for a He-SF6 Interface

    NASA Astrophysics Data System (ADS)

    Weber, Christopher; Haehn, Nicholas; Motl, Bradley; Oakley, Jason; Anderson, Mark; Bonazza, Riccardo; Greenough, Jeffrey

    2007-11-01

    Computational simulations of the Richtmyer-Meshkov (RM) instability are performed using the 2D Eulerian AMR code Raptor (LLNL) for a perturbed gas interface of helium over sulfur-hexafluoride. The interfacial modal content of the initial conditions for these simulations are directly obtained from the recent experiments carried out at the University of Wisconsin Shock Tube Laboratory. In the simulation, performed at a resolution of 128 grid points per wavelength, the interface is accelerated by a planar shock wave of varying strength (1.1 < M < 2). These very high Atwood number (A=0.95) interfaces result in asymmetrical bubble/sphere growth in the early stages of the RM instability development and a near pinch-off of the heavy fluid located at the spike tip in the very late stages. The computed solutions are compared to experimental results and several analytic models.

  2. Earth Observatory Satellite system definition study. Report no. 2: Instrument constraints and interface specifications

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The instruments to be flown on the Earth Observatory Satellite (EOS) system are defined. The instruments will be used to support the Land Resources Management (LRM) mission of the EOS. Program planning information and suggested acquisition activities for obtaining the instruments are presented. The subjects considered are as follows: (1) the performance and interface of the Thematic Mapper (TM) and the High Resolution Pointing Imager (HRPI), (2) procedure for interfacing the TM and HRPI with the EOS satellite, (3) a space vehicle integration plan suggesting the steps and sequence of events required to carry out the interface activities, and (4) suggested agreements between the contractors for providing timely and equitable solution of problems at minimum cost.

  3. X-ray photoelectron spectroscopy study of catalyzed aluminum carbide formation at aluminum-carbon interfaces

    NASA Technical Reports Server (NTRS)

    Rabenberg, L.; Maruyama, Benji

    1990-01-01

    Aluminum carbide may form at aluminum-graphite interfaces during the high-temperature processing of graphite fiber-reinforced aluminum metal matrix composites. The chemical interactions leading to the formation of the aluminum carbide in the solid state involve the breaking of the carbon-carbon bonds within the graphite, the transport of the carbon atoms across the interface, and the reaction with the aluminum to form Al4C3. The aluminum carbide formation process has been followed using X-ray photoelectron spectroscopy of model, thin-film, reaction couples. The overall reaction is shown to be catalyzed by the presence of water vapor. Water at the interface increases reaction kinetics by apparently weakening the bonds between the surface carbon atoms and their substrate. This result is in general agreement with what is known to occur during the oxidation of graphite in air.

  4. Molecular Dynamics Studies of Structure and Functions of Water-Membrane Interfaces

    NASA Technical Reports Server (NTRS)

    Pohorille, Andrew; Wilson, Michael A.; DeVincenzi, Donald L. (Technical Monitor)

    2001-01-01

    A large number of essential cellular processes occur at the interfaces between water and membranes. The selectivity and dynamics of these processes are largely determined by the structural and electrical properties of the water-membrane interface. We investigate these properties by the molecular dynamics method. Over the time scales of the simulations, the membrane undergoes fluctuations described by the capillary wave model. These fluctuations produce occasional thinning defects in the membrane which provide effective pathways for passive transport of ions and small molecules across the membrane. Ions moving through the membrane markedly disrupt its structure and allow for significant water penetration into the membrane interior. Selectivity of transport, with respect to ionic charge, is determined by the interfacial electrostatic potential. Many small molecules. of potential significance in catalysis, bioenergetics and pharmacology, are shown to bind to the interface. The energetics and dynamics of this process will be discussed.

  5. Theoretical and experimental studies of electrified interfaces relevant to energy storage.

    SciTech Connect

    Templeton, Jeremy Alan; Jones, Reese E.; Lee, Jonathan W.; Mandadapu, Kranthi Kiran; Kliewer, Christopher Jesse; Sasaki, Darryl Yoshio; Kane, Marie C.; Reyes, Karla Rosa; Hayden, Carl C.

    2013-12-01

    Advances in technology for electrochemical energy storage require increased understanding of electrolyte/electrode interfaces, including the electric double layer structure, and processes involved in charging of the interface, and the incorporation of this understanding into quantitative models. Simplified models such as Helmholtz's electric double-layer (EDL) concept don't account for the molecular nature of ion distributions, solvents, and electrode surfaces and therefore cannot be used in predictive, high-fidelity simulations for device design. This report presents theoretical results from models that explicitly include the molecular nature of the electrical double layer and predict critical electrochemical quantities such as interfacial capacitance. It also describes development of experimental tools for probing molecular properties of electrochemical interfaces through optical spectroscopy. These optical experimental methods are designed to test our new theoretical models that provide descriptions of the electric double layer in unprecedented detail.

  6. Trace Element Speciation and Distribution Study at Shewanella oneidensis MR-1 Biofilm/Mineral/Water Interfaces

    NASA Astrophysics Data System (ADS)

    Gelabert, A.; Wang, Y.; Gescher, J.; Ha, J.; Cordova, C. D.; Singer, D. M.; Spormann, A. M.; Trainor, T. P.; Eng, P. J.; Brown, G. E.

    2006-12-01

    the interactions among biofilm, metal(loid)s, and mineral surfaces. The long-period X-ray Standing Wave- fluorescent yield (XSW-FY) method, performed on BL ID-13-C at the APS, was used to obtain quantitative in situ information on the partitioning of Zn(II), Pb(II), and As(V) at these interfaces as a function of pH and ion concentration. XSW-FY results show that S. oneidensis biofilms do not block reactive sites on the hematite or alumina surfaces under our experimental conditions, which is consistent with the conclusion of our previous studies on trace element distributions at Burkholderia cepacia/mineral/water interfaces. Comparison of the observed trace element partitioning measured by XSW-FY with theoretical predictions of partitioning through thermodynamic models (using binding constants of metal(loid)s with the biofilm determined in this study and published binding constants of metal(loid)s with mineral substrates) allows us to describe biofilm local microenvironments and to understand how the biofilm coatings affect the reactivity of mineral surfaces.

  7. Space shuttle/food system study. Volume 1: Technical volume, oven study

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The baseline space shuttle galley was designed to utilize lightweight rehydratable foods, to be prepared for consumption by rehydration with chilled or hot water. The impact is examined of an extension of food types to include thermostabilized food, at ambient temperature, and frozen foods on the baseline design of the shuttle galley. Weight, volume, and power penalities associated with heating thermostabilized and frozen foods by means of a hot air convection heating system and a conduction heating system are determined along with the impact on crew/galley interface and meal preparation.

  8. Physicochemical Study of Viral Nanoparticles at the Air/Water Interface.

    PubMed

    Torres-Salgado, Jose F; Comas-Garcia, Mauricio; Villagrana-Escareño, Maria V; Durán-Meza, Ana L; Ruiz-García, Jaime; Cadena-Nava, Ruben D

    2016-07-01

    The assembly of most single-stranded RNA (ssRNA) viruses into icosahedral nucleocapsids is a spontaneous process driven by protein-protein and RNA-protein interactions. The precise nature of these interactions results in the assembly of extremely monodisperse and structurally indistinguishable nucleocapsids. In this work, by using a ssRNA plant virus (cowpea chlorotic mottle virus [CCMV]) as a charged nanoparticle we show that the diffusion of these nanoparticles from the bulk solution to the air/water interface is an irreversible adsorption process. By using the Langmuir technique, we measured the diffusion and adsorption of viral nucleocapsids at the air/water interface at different pH conditions. The pH changes, and therefore in the net surface charge of the virions, have a great influence in the diffusion rate from the bulk solution to the air/water interface. Moreover, assembly of mesoscopic and microscopic viral aggregates at this interface depends on the net surface charge of the virions and the surface pressure. By using Brewster's angle microscopy we characterized these structures at the interface. Most common structures observed were clusters of virions and soap-frothlike micron-size structures. Furthermore, the CCMV films were compressed to form monolayers and multilayers from moderate to high surface pressures, respectively. After transferring the films from the air/water interface onto mica by using the Langmuir-Blodgett technique, their morphology was characterized by atomic force microscopy. These viral monolayers showed closed-packing nano- and microscopic arrangements. PMID:26999022

  9. Study of orbiter/payload interface communications configuration control board directive from an operational perspective

    NASA Technical Reports Server (NTRS)

    Addis, A. W.; Tatosian, C. G.; Lidsey, J. F.

    1974-01-01

    Orbiter/payload data and communications interface was examined. It was found that the Configuration Control Board Directive (CCBD) greatly increases the capability of the orbiter to communicate with a wide variety of projected shuttle payloads. Rather than being derived from individual payload communication requirements, the CCBD appears to be based on an operational philosophy that requires the orbiter to duplicate or augment the ground network/payload communication links. It is suggested that the implementation of the CCBD be reviewed and compared with the Level 1 Program Requirements Document, differences reconciled, and interface characteristics defined.

  10. A study of adhesion at the E-glass/FR4 interface

    SciTech Connect

    Kent, M.S.; Baca, P.; McNarama, W.F.; Jones, G.; Fein, D.; Wright, W.; Domeier, L.; Wu, W.L.; Wong, A.

    1995-11-01

    The majority of printed circuit boards are copper clad laminates composed of fiberglass cloth impregnated with FR4 epoxy. An important factor affecting the reliability of these assemblies is the integrity of the epoxy/glass fiber interface. The goal of this work is to investigate mechanisms for the loss of adhesive strength between E-glass and FR4 epoxy upon humidity and temperature conditioning. In this paper the authors discuss the distribution of moisture between the interface region and the bulk epoxy examined by neutron reflection, and the relationship of this data to adhesive strength.

  11. A comparative study of interface reconstruction methods for multi-material ALE simulations

    SciTech Connect

    Kucharik, Milan; Garimalla, Rao; Schofield, Samuel; Shashkov, Mikhail

    2009-01-01

    In this paper we compare the performance of different methods for reconstructing interfaces in multi-material compressible flow simulations. The methods compared are a material-order-dependent Volume-of-Fluid (VOF) method, a material-order-independent VOF method based on power diagram partitioning of cells and the Moment-of-Fluid method (MOF). We demonstrate that the MOF method provides the most accurate tracking of interfaces, followed by the VOF method with the right material ordering. The material-order-independent VOF method performs some-what worse than the above two while the solutions with VOF using the wrong material order are considerably worse.

  12. Experimental study on mechanical behavior of fiber/matrix interface in metal matrix composite

    SciTech Connect

    Wang, Q.; Chiang, F.P.

    1994-12-31

    The technique SIEM(Speckle Interferometry with Electron Microscopy) was employed to quantitatively measure the deformation on the fiber/matrix interface in SCS-6/Ti-6-4 composite at a microscale level. The displacement field within the fiber/matrix interphase zone was determined by in-situ observation with sensitivity of 0.003({micro}m). The macro-mechanical properties were compared with micro-mechanical behavior. It is shown that the strength in the interphase zone is weaker than the matrix tensile strength. The deformation process can be characterized by the uniform deformation, interface strain concentration and debond, and matrix plastic deformation.

  13. Technical and Conceptual Considerations for Performing and Interpreting Functional MRI Studies in Awake Rats

    PubMed Central

    Febo, Marcelo

    2011-01-01

    Functional neuroimaging studies in rodents have the potential to provide insight into neurodevelopmental and psychiatric conditions. The strength of the technique lies in its non-invasive nature that can permit longitudinal functional studies in the same animal over its adult life. The relatively good spatial and temporal resolution and the ever-growing database on the biological and biophysical basis of the blood oxygen level dependent (BOLD) signal make it a unique technique in preclinical neuroscience research. Our laboratory has used imaging to investigate brain activation in awake rats following cocaine administration and during the presentation of lactation-associated sensory stimuli. Factors that deserve attention when planning functional magnetic resonance imaging studies in rats include technical issues, animal physiology and interpretability of the resulting data. The present review discusses the pros and cons of animal imaging with a particular focus on the technical aspects of studies with awake rats. Overall, the benefits of the technique outweigh its limitations and the rapidly evolving methods will open the way for more laboratories to employ the technique in neuroscience research. PMID:21808625

  14. Experimental studies on irreversibility of electrostatic adsorption of silica nanoparticles at solid-liquid interface.

    PubMed

    Li, Xue; Niitsoo, Olivia; Couzis, Alexander

    2014-04-15

    Adsorption of colloidal nanoparticles (NPs) at solid-liquid interface is a scientifically interesting and technologically important phenomenon due to its fundamental importance in many industrial, environmental, and biological processes, such as wastewater treatment, printing, coating of surfaces, chromatography, papermaking, or biocompatibility. The process is well understood theoretically by the random sequential adsorption (RSA) model, based on the assumption of irreversible adsorption. Irreversible adsorption is defined as a process in which, once adsorbed, a particle can neither desorb, nor to move laterally on the surface. However, published experimental data that verifies the irreversibility of particle adsorption are very limited. In this study, we demonstrate the irreversibility of electrostatically driven nanoparticle adsorption utilizing a carefully selected set of experiments. A simple method was employed by uniquely introducing Ag@SiO2 core/shell NPs to perform exchange adsorptions experiments. Stöber SiO2 NPs with a diameter of 50-80 nm were initially electrostatically adsorbed onto amino-functionalized silicon wafer substrates followed by the subsequent adsorption of Ag@SiO2 NPs. The Ag@SiO2 NPs have the same surface chemistry as the neat SiO2 NPs. For the second step the adsorption time was varied from 1 min to 1 week so as to get a thorough understanding of the process irreversibility. Surface coverage quantification has shown that the surface coverage of the initially adsorbed SiO2 NPs stays the same independent of the duration of the second step adsorption using the Ag@SiO2 core/shell NPs. This observation directly confirms the irreversibility of electrostatic adsorption of NPs. PMID:24559699

  15. Diffuse interface methods for inverse problems: case study for an elliptic Cauchy problem

    NASA Astrophysics Data System (ADS)

    Burger, Martin; Løseth Elvetun, Ole; Schlottbom, Matthias

    2015-12-01

    Many inverse problems have to deal with complex, evolving and often not exactly known geometries, e.g. as domains of forward problems modeled by partial differential equations. This makes it desirable to use methods which are robust with respect to perturbed or not well resolved domains, and which allow for efficient discretizations not resolving any fine detail of those geometries. For forward problems in partial differential equations methods based on diffuse interface representations have gained strong attention in the last years, but so far they have not been considered systematically for inverse problems. In this work we introduce a diffuse domain method as a tool for the solution of variational inverse problems. As a particular example we study ECG inversion in further detail. ECG inversion is a linear inverse source problem with boundary measurements governed by an anisotropic diffusion equation, which naturally cries for solutions under changing geometries, namely the beating heart. We formulate a regularization strategy using Tikhonov regularization and, using standard source conditions, we prove convergence rates. A special property of our approach is that not only operator perturbations are introduced by the diffuse domain method, but more important we have to deal with topologies which depend on a parameter \\varepsilon in the diffuse domain method, i.e. we have to deal with \\varepsilon -dependent forward operators and \\varepsilon -dependent norms. In particular the appropriate function spaces for the unknown and the data depend on \\varepsilon . This prevents the application of some standard convergence techniques for inverse problems, in particular interpreting the perturbations as data errors in the original problem does not yield suitable results. We consequently develop a novel approach based on saddle-point problems. The numerical solution of the problem is discussed as well and results for several computational experiments are reported. In

  16. Musculoskeletal clinical assessment and treatment services at the primary-secondary care interface: an observational study

    PubMed Central

    Roddy, Edward; Zwierska, Irena; Jordan, Kelvin P; Dawes, Peter; Hider, Samantha L; Packham, Jon; Stevenson, Kay; Hay, Elaine M

    2013-01-01

    Background Management of musculoskeletal conditions in the UK is increasingly delivered in multidisciplinary clinical assessment and treatment services (CATS) at the primary–secondary care interface. However, there is little evidence concerning the characteristics and management of patients attending CATS. Aim To describe the characteristics, investigation, and treatment of adults attending a musculoskeletal CATS. Design and setting Cross-sectional analysis of cohort study baseline data from a musculoskeletal CATS in Stoke-on-Trent Primary Care Trust, UK. Method All patients referred from primary care between February 2008 and June 2009 were mailed a pre-consultation questionnaire concerning pain duration, general health status, anxiety, depression, employment status, and work absence due to musculoskeletal problems. At the consultation, clinical diagnoses, body region(s) affected, investigations, and treatment were recorded. Result A total of 2166 (73%) completed questionnaires were received. Chronic pain duration >1 year (55%), major physical limitation (76%), anxiety (49%), and depression (37%) were common. Of those currently employed, 516 (45%) had taken time off work in the last 6 months because of their musculoskeletal problem; 325 (29%) were unable to do their usual job. The most frequent investigations were X-rays (23%), magnetic resonance imaging (18%), and blood tests (14%): 1012 (48%) received no investigations. Injections were performed in 282 (13%) and 492 (23%) were referred to physiotherapy. Conclusion Although most patients presented with musculoskeletal problems suitable for CATS, chronic pain, physical limitation, anxiety, depression, and work disability were commonplace, highlighting the need for a biopsychosocial model of care that addresses psychological, social, and work-related needs, as well as pain and physical disability. PMID:23561693

  17. Brain-Machine-Interface in Chronic Stroke Rehabilitation: A Controlled Study

    PubMed Central

    Ramos-Murguialday, Ander; Broetz, Doris; Rea, Massimiliano; Läer, Leonhard; Yilmaz, Özge; Brasil, Fabricio L; Liberati, Giulia; Curado, Marco R; Garcia-Cossio, Eliana; Vyziotis, Alexandros; Cho, Woosang; Agostini, Manuel; Soares, Ernesto; Soekadar, Surjo; Caria, Andrea; Cohen, Leonardo G; Birbaumer, Niels

    2013-01-01

    Objective Chronic stroke patients with severe hand weakness, respond poorly to rehabilitation efforts. Here, we evaluated efficacy of daily brain-machine-interface training to increase the hypothesized beneficial effects of physiotherapy alone in patients with severe paresis in a double blind sham-controlled design proof of concept study. Methods 32 chronic stroke patients with severe hand weakness, were randomly assigned to two matched groups and participated in 17.8 ± 1.4 days of training rewarding desynchronization of ipsilesional oscillatory sensorimotor rhythms (SMR) with contingent online movements of hand and arm orthoses (experimental group , n=16). In the control group (sham group, n=16) movements of the orthoses occurred randomly. Both groups received identical behavioral physiotherapy immediately following BMI training or the control intervention. Upper limb motor function scores, electromyography from arm and hand muscles, placebo-expectancy effects and functional magnetic resonance imaging (MRI) blood oxygenation level dependent activity were assessed before and after intervention. Results A significant group × time interaction in upper limb Fugl-Meyer motor (cFMA) scores was found. cFMA scores improved more in the experimental than in the control group, presenting a significant improvement of cFMA scores (3.41±0.563 points difference, p=0.018) reflecting a clinically meaningful change from no activity to some in paretic muscles. cFMA improvements in the experimental group correlated with changes in functional MRI laterality index and with paretic hand electromyography activity. Placebo-expectancy scores were comparable for both groups. Interpretation The addition of BMI training to behaviorally oriented physiotherapy can be used to induce functional improvements in motor function in chronic stroke patients without residual finger movements and may open a new door in stroke neurorehabilitation. PMID:23494615

  18. Atomic force microscopy study of nitrogen molecule self-assembly at the HOPG-water interface

    NASA Astrophysics Data System (ADS)

    Lu, Yi-Hsien; Yang, Chih-Wen; Hwang, Ing-Shouh

    2014-06-01

    In this work, we investigated the evolution of the graphite-water interface in a nitrogen atmosphere by using frequency-modulation atomic force microscopy (FM-AFM). A highly ordered pyrolytic graphite (HOPG) sample was immersed in pre-degassed water and subsequently placed in the nitrogen environment. The dissolved nitrogen molecules diffused in water and self-assembled into ordered row-like structural domains at the interface. Nucleation and growth processes of the domains were observed. When the coverage of the ordered structure surpassed 50%, small clusters began to appear on the ordered structure. The number density of the clusters increases as the coverage of the ordered structures increases and these clusters may hop on the ordered structures. A model is proposed to explain the evolution of the nitrogen molecule self-assembly process at the interface. The observation of nitrogen clusters may shed light on the nature and nucleation of the so-called nanobubbles at hydrophobic-water interfaces.

  19. A Chemical and Structural Study of the A1N-Si Interface

    NASA Technical Reports Server (NTRS)

    George, T.; Beye, R.

    1997-01-01

    Samples of A1N grown on silicon [111] subtrates were examined using electron enery loss spectroscopy (EELS) and selected area diffraction (SAD) with high-resolution transmission electron microscopy (TEM) to determine the source of out-of-place tilts and in-plane rotations of the A1N crystallites at the Si interface.

  20. The behavior of NaOH at the air-water interface, a computational study

    SciTech Connect

    Wick, Collin D.; Dang, Liem X.

    2010-07-14

    Molecular dynamics simulations with a polarizable multi-state empirical valence bond model were carried out to investigate NaOH dissociation and pairing in water bulk and at the air-water interface. It was found that NaOH readily dissociates in the bulk, and the effect of the air-water interface on NaOH dissociation is fairly minor. Also, NaOH complexes were found to be strongly repelled from the air-water interface, which is consistent with surface tension measurements. At the same time, a very strong preference for the hydroxide anion to be oriented towards the air was found that persisted a few angstroms towards the liquid from the Gibbs dividing surface of the air-water interface. This was due to a preference for the hydroxide anion to have its hydrogen pointing towards the air, and the fact that the sodium ion was more likely to be found near the hydroxide oxygen than hydrogen. As a consequence, the simulation results show that surfaces of NaOH solutions should be negatively charged, in agreement with experimental observations, but also that the hydroxide has little surface affinity. This provides the possibility that the surface of water can be devoid of hydroxide anions, but still have a strong negative charge. This work was supported by the US Department of Energy Basic Energy Sciences' Chemical Sciences, Geosciences & Biosciences Division. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

  1. A study of adhesion at the E-glass/FR4 interface

    SciTech Connect

    Kent, M.S.; Baca, P.; McNamara, W.F.

    1995-12-31

    The goal of this work is to investigate mechanisms for the loss of adhesive strength between E-glass and FR4 epoxy upon-humidity and temperature conditioning. In this paper we discuss the distribution of moisture between the interface region and the bulk epoxy examined by neutron reflection, and the relationship of this data to adhesive strength.

  2. Scanning capacitance microscope study of a SiO2/Si interface modified by charge injection

    NASA Astrophysics Data System (ADS)

    Tomiye, H.; Yao, T.

    We have investigated the local electrical properties of an SiO2/Si structure using a scanning capacitance microscope (SCaM) combined with an atomic force and a scanning tunneling microscope (AFM and STM). The electrical properties of the Si substrate and the SiO2/Si interface vary with position. In this experiment we have injected charge into the SiO2 and investigated the nature of charge storage at the SiO2/Si interface. We have used the combined microscope to apply a pulse to the SiO2/Si sample, causing charge to be trapped in the SiO2/Si interface. We could clearly detect the local variation of interface charge in a non-destructive manner using the SCaM and simultaneously by capacitance-voltage (C-V) characterization. The volume of the C-V curve shift along the voltage axis due to trapped charges is dependent upon the density of the trapped charges. In doing this experiment we show one of the many possible applications of the combined SCaM/AFM/STM.

  3. A self-consistent field study of a hydrocarbon droplet at the air-water interface.

    PubMed

    Hilz, Emilia; Leermakers, Frans A M; Vermeer, Arnoldus W P

    2012-04-14

    A molecularly detailed self-consistent field (SCF) approach is applied to describe a sessile hydrocarbon droplet placed at the air-water interface. Predictions of the contact angle for macroscopic droplets follow from using Neumann's equation, wherein the macroscopic interfacial tensions are computed from one-gradient calculations for flat interfaces. A two-gradient cylindrical coordinate system with mirror-like boundary conditions is used to analyse the three dimensional shape of the nano-scale oil droplet at the air-water interface. These small droplets have a finite value of the Laplace pressure and concomitant line tension. It has been calculated that the oil-water and oil-vapour interfacial tensions are curvature dependent and increase slightly with increasing interfacial curvature. In contrast, the line tension tends to decrease with curvature. In all cases there is only a weak influence of the line tension on the droplet shape. We therefore argue that the nano-scale droplets, which are described in the SCF approach, are representative for macroscopic droplets and that the method can be used to efficiently generate accurate information on the spreading of oil droplets at the air-water interface in molecularly more complex situations. As an example, non-ionic surfactants have been included in the system to illustrate how a molecularly more complex situation will change the wetting properties of the sessile drop. This short forecast is aimed to outline and to stress the potential of the method. PMID:22395192

  4. Local/Global Cognitive Interfaces within Industrial Districts: An Italian Case Study

    ERIC Educational Resources Information Center

    Grandinetti, Roberto

    2011-01-01

    Purpose: With the advance of globalization the competitive chances of industrial districts depends increasingly on their ability to connect to the cognitive circuits of the global economy. This challenge demands the presence of local actors capable of acting as cognitive interfaces between the district context and the global environment. The paper…

  5. Functional Literacy, Workplace Literacy and Technical and Vocational Education: Interfaces and Policy Perspectives. UNEVOC Studies in Technical and Vocational Education 5.

    ERIC Educational Resources Information Center

    Bhola, H. S.

    To achieve the intergenerational social reproduction of labor, all societies develop suitable institutional arrangements for the delivery of "Education and Training for Work" (ETW). Three programs together constitute the bulk of ETW initiatives in almost every country on the globe: functional literacy (FL), workplace literacy (WPL), and technical…

  6. Developing Human Resources for the Technical Workforce: A Comparative Study of Korea and Thailand

    ERIC Educational Resources Information Center

    Hawley, Joshua D.; Paek, Jeeyon

    2005-01-01

    Asian countries face significant and growing shortages of technically skilled workers. Vocational-technical systems are key components of national human resource development. Using labor market data from Thailand and Korea, this paper analyzes the economic payoff for individual investment in vocational-technical education, and subsequent…

  7. Structure of alkylimidazolium-based ionic liquids at the interface with vacuum and water--a molecular dynamics study.

    PubMed

    Konieczny, Jan K; Szefczyk, Borys

    2015-03-01

    Ionic liquid (IL) interfaces with vacuum and water are studied by means of classical molecular dynamics simulations. Five ILs are compared: [C2mim][TfO], [C12mim][TfO], [C2mim][NTf2], [C8mim][NTf2] and [C12mim][NTf2], where [C2mim], [C8mim] and [C12mim] stand for 1-ethyl-, 1-octyl- and 1-dodecyl-3-methylimidazolium cation. Physical properties-density, thermal expansion coefficient, compressibility, surface tension, heat of vaporization, self-diffusion coefficient, electric conductivity and viscosity-are calculated and validated against experimental values. The structure of the interfaces is compared in terms of the orientation of the molecules and segregation into layers. It is observed that ILs with short alkyl chains orient at the surface; however, there is no single preferred orientation. ILs with longer chains, on the other hand, orient with alkyl chains protruding into the vacuum at the IL/vacuum interface and into the bulk IL, at the IL/water interface. Anions and water molecules tend to associate with polar imidazolium groups. PMID:25674908

  8. Numerical studies of the scattering of light from a two-dimensional randomly rough interface between two dielectric media

    NASA Astrophysics Data System (ADS)

    Hetland, Ø. S.; Maradudin, A. A.; Nordam, T.; Simonsen, I.

    2016-05-01

    The scattering of polarized light incident from one dielectric medium on its two-dimensional randomly rough interface with a second dielectric medium is studied. A reduced Rayleigh equation for the scattering amplitudes is derived for the case where p- or s-polarized light is incident on this interface, with no assumptions being made regarding the dielectric functions of the media. Rigorous, purely numerical, nonperturbative solutions of this equation are obtained. They are used to calculate the reflectivity and reflectance of the interface, the mean differential reflection coefficient, and the full angular distribution of the intensity of the scattered light. These results are obtained for both the case where the medium of incidence is the optically less dense medium and in the case where it is the optically more dense medium. Optical analogs of the Yoneda peaks observed in the scattering of x rays from metal surfaces are present in the results obtained in the latter case. Brewster scattering angles for diffuse scattering are investigated, reminiscent of the Brewster angle for flat-interface reflection, but strongly dependent on the angle of incidence. When the contribution from the transmitted field is added to that from the scattered field it is found that the results of these calculations satisfy unitarity with an error smaller than 10-4.

  9. Study of wetting on chemically soften interfaces by using combined solution thermodynamics and DFT calculations: forecasting effective softening elements.

    PubMed

    Shu, Guo Gang; Xu, Qiang; Wu, Ping

    2015-04-15

    Despite recent progress in understanding the wetting principles on soft solids, the roles of chemical bonding in the formation of interfaces have been largely ignored, because most of these studies are conducted at room temperatures. Here we propose a universal wetting principle from solution thermodynamics to account for the softening of both the solid and liquid surfaces (stable or metastable). Density functional theory (DFT) calculations are applied to evaluate the stability and electron transportation across the interfaces. We find that wetting is dominated by the system entropy changes involving not only the stable liquid alloy phase but also the metastable liquid oxide phases. The state-of-art multicomponent solution thermodynamic models and databases are applied to describe the entropy changes and predict the wetting behaviors. Our results show that by chemically softening either the liquid or the solid phase, the wetting angle reduces. And an effective soften agent/additive (either in the form of chemical elements or molecules) will weaken the bonds within the liquid (or solid) phase and promote new bonds at the interfaces, thus increasing the interface entropy. Subsequently, as an example, Ti and Zr are proposed as effective softening elements to improve the wetting of aluminum liquid on B6Si(s). This approach provides a concept and tool to advance research in catalytic chemistry, nucleation (growth), elastowetting, and cell-substrate interactions. PMID:25844936

  10. The application of the symmetry properties of optical second harmonic generation to studies of interfaces and gases

    SciTech Connect

    Feller, M.B.

    1991-11-01

    Optical second harmonic generation has proven to be a powerful tool for studying interfaces. The symmetry properties of the process allow for surface sensitivity not available with other optical methods. In this thesis, we take advantage of these symmetry properties SHG to study a variety of interesting systems not previously studied with this technique. We show that optical second harmonic generation is an effective surface probe with a submonolayer sensitivity for media without inversion symmetry. We demonstrate the technique at a gallium arsenide surface, exploiting the different symmetry properties of the bulk and surface of the crystal to isolate the surface contribution. We also demonstrate that optical second harmonic generation can be used to determine the anisotropic orientational distribution of a surface monolayer of molecules. We apply the technique to study homogeneously aligned liquid crystal cells. To further explore the LC-polymer interface, we used SHG to study the surface memory effect. The surface memory effect is the rendering of an isotropic interface anisotropic by putting it in contact with an anisotropic bulk. Last, we describe some preliminary measurements of a time-resolved spectroscopic study of the phenomenon of second harmonic generation in a gas. The construction of a 500 microjoule pulsed, tunable laser source is described.

  11. Wildfire risk in the wildland-urban interface: A simulation study in northwestern Wisconsin

    USGS Publications Warehouse

    Bar-Massada, A.; Radeloff, V.C.; Stewart, S.I.; Hawbaker, T.J.

    2009-01-01

    The rapid growth of housing in and near the wildland-urban interface (WUI) increases wildfire risk to lives and structures. To reduce fire risk, it is necessary to identify WUI housing areas that are more susceptible to wildfire. This is challenging, because wildfire patterns depend on fire behavior and spread, which in turn depend on ignition locations, weather conditions, the spatial arrangement of fuels, and topography. The goal of our study was to assess wildfire risk to a 60,000 ha WUI area in northwestern Wisconsin while accounting for all of these factors. We conducted 6000 simulations with two dynamic fire models: Fire Area Simulator (FARSITE) and Minimum Travel Time (MTT) in order to map the spatial pattern of burn probabilities. Simulations were run under normal and extreme weather conditions to assess the effect of weather on fire spread, burn probability, and risk to structures. The resulting burn probability maps were intersected with maps of structure locations and land cover types. The simulations revealed clear hotspots of wildfire activity and a large range of wildfire risk to structures in the study area. As expected, the extreme weather conditions yielded higher burn probabilities over the entire landscape, as well as to different land cover classes and individual structures. Moreover, the spatial pattern of risk was significantly different between extreme and normal weather conditions. The results highlight the fact that extreme weather conditions not only produce higher fire risk than normal weather conditions, but also change the fine-scale locations of high risk areas in the landscape, which is of great importance for fire management in WUI areas. In addition, the choice of weather data may limit the potential for comparisons of risk maps for different areas and for extrapolating risk maps to future scenarios where weather conditions are unknown. Our approach to modeling wildfire risk to structures can aid fire risk reduction management

  12. Why standard brain-computer interface (BCI) training protocols should be changed: an experimental study

    NASA Astrophysics Data System (ADS)

    Jeunet, Camille; Jahanpour, Emilie; Lotte, Fabien

    2016-06-01

    Objective. While promising, electroencephaloraphy based brain–computer interfaces (BCIs) are barely used due to their lack of reliability: 15% to 30% of users are unable to control a BCI. Standard training protocols may be partly responsible as they do not satisfy recommendations from psychology. Our main objective was to determine in practice to what extent standard training protocols impact users’ motor imagery based BCI (MI-BCI) control performance. Approach. We performed two experiments. The first consisted in evaluating the efficiency of a standard BCI training protocol for the acquisition of non-BCI related skills in a BCI-free context, which enabled us to rule out the possible impact of BCIs on the training outcome. Thus, participants (N = 54) were asked to perform simple motor tasks. The second experiment was aimed at measuring the correlations between motor tasks and MI-BCI performance. The ten best and ten worst performers of the first study were recruited for an MI-BCI experiment during which they had to learn to perform two MI tasks. We also assessed users’ spatial ability and pre-training μ rhythm amplitude, as both have been related to MI-BCI performance in the literature. Main results. Around 17% of the participants were unable to learn to perform the motor tasks, which is close to the BCI illiteracy rate. This suggests that standard training protocols are suboptimal for skill teaching. No correlation was found between motor tasks and MI-BCI performance. However, spatial ability played an important role in MI-BCI performance. In addition, once the spatial ability covariable had been controlled for, using an ANCOVA, it appeared that participants who faced difficulty during the first experiment improved during the second while the others did not. Significance. These studies suggest that (1) standard MI-BCI training protocols are suboptimal for skill teaching, (2) spatial ability is confirmed as impacting on MI-BCI performance, and (3) when faced

  13. In Vitro Multitissue Interface Model Supports Rapid Vasculogenesis and Mechanistic Study of Vascularization across Tissue Compartments.

    PubMed

    Buno, Kevin P; Chen, Xuemei; Weibel, Justin A; Thiede, Stephanie N; Garimella, Suresh V; Yoder, Mervin C; Voytik-Harbin, Sherry L

    2016-08-31

    A significant challenge facing tissue engineers is the design and development of complex multitissue systems, including vascularized tissue-tissue interfaces. While conventional in vitro models focus on either vasculogenesis (de novo formation of blood vessels) or angiogenesis (vessels sprouting from existing vessels or endothelial monolayers), successful therapeutic vascularization strategies will likely rely on coordinated integration of both processes. To address this challenge, we developed a novel in vitro multitissue interface model in which human endothelial colony forming cell (ECFC)-encapsulated tissue spheres are embedded within a surrounding tissue microenvironment. This highly reproducible approach exploits biphilic surfaces (nanostructured surfaces with distinct superhydrophobic and hydrophilic regions) to (i) support tissue compartments with user-specified matrix composition and physical properties as well as cell type and density and (ii) introduce boundary conditions that prevent the cell-mediated tissue contraction routinely observed with conventional three-dimensional monodispersion cultures. This multitissue interface model was applied to test the hypothesis that independent control of cell-extracellular matrix (ECM) and cell-cell interactions would affect vascularization within the tissue sphere as well as across the tissue-tissue interface. We found that high-cell-density tissue spheres containing 5 × 10(6) ECFCs/mL exhibit rapid and robust vasculogenesis, forming highly interconnected, stable (as indicated by type IV collagen deposition) vessel networks within only 3 days. Addition of adipose-derived stromal cells (ASCs) in the surrounding tissue further enhanced vasculogenesis within the sphere as well as angiogenic vessel elongation across the tissue-tissue boundary, with both effects being dependent on the ASC density. Overall, results show that the ECFC density and ECFC-ASC crosstalk, in terms of paracrine and mechanophysical signaling

  14. Development of a teaching tool to encourage high school students to study aerospace technical subjects

    NASA Technical Reports Server (NTRS)

    Gale, Anita; Edwards, Dick

    1998-01-01

    This report details the efforts to develop a design competition aimed at high school students which will encourage them to study aerospace technical subjects. It has been shown that such competitions - based on an industry simulation game - are valuable ways to energize high school students to study in this area. Under the grant, a new competition scenario was developed, in keeping with NASA-Dryden's mission to develop aircraft and foster knowledge about aeronautics. Included are preliminary background materials and information which, if the grant is continued, would form the basis of a national competition for high school students, wherein they would design an Aerospaceport in a future year, taking into consideration the requirements of aircraft, spacecraft- ground transportation systems, passengers who use the facility, and employees who operate it. Many of the Competition methods were studied and tested during two existing local competitions in the disadvantaged communities of Lancaster and Victorville, California.

  15. Mechanistic Studies at the Interface Between Organometallic Chemistry and Homogeneous Catalysis

    SciTech Connect

    Casey, Charles P

    2012-11-14

    Mechanistic Studies at the Interface Between Organometallic Chemistry and Homogeneous Catalysis Charles P. Casey, Principal Investigator Department of Chemistry, University of Wisconsin - Madison, Madison, Wisconsin 53706 Phone 608-262-0584 FAX: 608-262-7144 Email: casey@chem.wisc.edu http://www.chem.wisc.edu/main/people/faculty/casey.html Executive Summary. Our goal was to learn the intimate mechanistic details of reactions involved in homogeneous catalysis and to use the insight we gain to develop new and improved catalysts. Our work centered on the hydrogenation of polar functional groups such as aldehydes and ketones and on hydroformylation. Specifically, we concentrated on catalysts capable of simultaneously transferring hydride from a metal center and a proton from an acidic oxygen or nitrogen center to an aldehyde or ketone. An economical iron based catalyst was developed and patented. Better understanding of fundamental organometallic reactions and catalytic processes enabled design of energy and material efficient chemical processes. Our work contributed to the development of catalysts for the selective and mild hydrogenation of ketones and aldehydes; this will provide a modern green alternative to reductions by LiAlH4 and NaBH4, which require extensive work-up procedures and produce waste streams. (C5R4OH)Ru(CO)2H Hydrogenation Catalysts. Youval Shvo described a remarkable catalytic system in which the key intermediate (C5R4OH)Ru(CO)2H (1) has an electronically coupled acidic OH unit and a hydridic RuH unit. Our efforts centered on understanding and improving upon this important catalyst for reduction of aldehydes and ketones. Our mechanistic studies established that the reduction of aldehydes by 1 to produce alcohols and a diruthenium bridging hydride species occurs much more rapidly than regeneration of the ruthenium hydride from the diruthenium bridging hydride species. Our mechanistic studies require simultaneous transfer of hydride from ruthenium to

  16. Neutron reflectometry study on an interface of octane and D 2O at low surfactant (C 10E 4) concentration

    NASA Astrophysics Data System (ADS)

    Jeng, U.; Esibov, L.; Crow, M. L.; Steyerl, A.

    1996-02-01

    We study the surface and interface roughness of a two-liquid film system using neutron reflectometry. The middle phase and bottom phase are extracted from a three-phase microemulsion containing 2 wt% non-ionic surfactant C 10E 4, 81 wt% D 2O and 17 wt% octane (C 8H 18). The system is formed by spreading a few drops of the middle phase of the microemulsion on the bottom phase of the microemulsion. The middle phase does not wet the bottom phase, but demixes to form a top octane-water mixture layer with a thickness of ∼ 580 Å. The mean surface roughness of the system is found to be 7 Å but the data are insensitive to interface roughness. An extended capillary wave model for a two-liquid-film system is derived to account for the coupling between the surface and interface. The dispersion relation yields two fundamental modes. In a calculation of mean-square roughness (< ζ2> 1/2) a high- k-cutoff is needed to account for non-linear terms in the Navier-Stokes equation. A low- k cutoff is also needed to avoid a “slip phenomenon” at the interface, which characterizes one of the modes. It turns out that for the parameters of our experiment the narrowing of k region is so significant that the mode causing the slip is strongly suppressed. As a consequence, the calculated interface roughness is much smaller than that derived from ordinary capillary wave theory.

  17. MARKET ASSESSMENT AND TECHNICAL FEASIBILITY STUDY OF PRESSURIZED FLUIDIZED BED COMBUSTION ASH USE

    SciTech Connect

    A.E. Bland; T.H. Brown

    1997-04-01

    Western Research Institute, in conjunction with the Electric Power Research Institute, Foster Wheeler International, Inc. and the US Department of Energy, has undertaken a research and demonstration program designed to examine the market potential and the technical feasibility of ash use options for PFBC ashes. Ashes from the Foster Wheeler Energia Oy pilot-scale circulating PFBC tests in Karhula, Finland, combusting (1) low-sulfur subbituminous and (2) high-sulfur bituminous coal, and ash from the AEP's high-sulfur bituminous coal-fired bubbling PFBC in Brilliant, Ohio, were evaluated in laboratory and pilot-scale ash use testing at WR1. The technical feasibility study examined the use of PFBC ash in construction-related applications, including its use as a cementing material in concrete and use in cement manufacturing, fill and embankment materials, soil stabilization agent, and use in synthetic aggregate production. Testing was also conducted to determine the technical feasibility of PFBC ash as a soil amendment for acidic and sodic problem soils and spoils encountered in agricultural and reclamation applications. The results of the technical feasibility testing indicated the following conclusions. PFBC ash does not meet the chemical requirements as a pozzolan for cement replacement. However, it does appear that potential may exist for its use in cement production as a pozzolan and/or as a set retardant. PFBC ash shows relatively high strength development, low expansion, and low permeability properties that make its use in fills and embankments promising. Testing has also indicated that PFBC ash, when mixed with low amounts of lime, develops high strengths, suitable for soil stabilization applications and synthetic aggregate production. Synthetic aggregate produced from PFBC ash is capable of meeting ASTM/AASHTO specifications for many construction applications. The residual calcium carbonate and calcium sulfate in the PFE3C ash has been shown to be of value in

  18. TOOKUIL: A case study in user interface development for safety code application

    SciTech Connect

    Gray, D.L.; Harkins, C.K.; Hoole, J.G.; Peebles, R.C.; Smith, R.J.

    1996-11-01

    Traditionally, there has been a very high learning curve associated with using nuclear power plant (NPP) analysis codes. Even for seasoned plant analysts and engineers, the process of building or modifying an input model for present day NPP analysis codes is tedious, error prone, and time consuming. Current cost constraints and performance demands place an additional burden on today`s safety analysis community. Advances in graphical user interface (GUI) technology have been applied to obtain significant productivity and quality assurance improvements for the Transient Reactor Analysis Code (TRAC) input model development. KAPL Inc. has developed an X Windows-based graphical user interface named TOOKUIL which supports the design and analysis process, acting as a preprocessor, runtime editor, help system, and post processor for TRAC. This paper summarizes the objectives of the project, the GUI development process and experiences, and the resulting end product, TOOKUIL.

  19. Sum-frequency vibrational spectroscopic studies of water/vapor interfaces

    NASA Astrophysics Data System (ADS)

    Tian, C. S.; Shen, Y. R.

    2009-02-01

    Phase-sensitive sum-frequency vibrational spectroscopy was used to obtain the OH and OD stretch spectra of the imaginary part of the nonlinear susceptibility, ImχS(2)(ωIR), for H 2O/vapor, D 2O/vapor, and 2:1 H 2O-D 2O/vapor interfaces that explicitly characterize their resonances. They all exhibit a positive and a negative resonance band in the bonded-OH region, clearly different from those deduced from fitting of the |χS(2)(ωIR)|2 spectra, and from MD simulations. The broad continuum is characteristic of inhomogeneously broadened resonances associated with interfacial water species of various hydrogen-bonding geometries and strengths. Spectral changes due to excess ions at the interfaces support the picture.

  20. Protein Folding at the Air-Water Interface Studied with X-Ray Reflectivity

    NASA Astrophysics Data System (ADS)

    Gidalevitz, David; Huang, Zhengqing; Rice, Stuart A.

    1999-03-01

    We report the results of x-ray reflectivity measurements of thin films formed by different water-soluble proteins at the air-aqueous solution interface. It is demonstrated that glucose oxidase, alcohol dehydrogenase, and urease molecules denaturate at the air-aqueous solution interface to form 8- to 14- angstrom -thick peptide sheets. X-ray reflectivity data indicate that the spreading of a lipid monolayer at the aqueous solution surface before protein injection does not prevent proteins from unfolding. On the other hand, crosslinking of proteins results in intact enzyme layers at the subphase surface. A model that involves interaction of glucose oxidase molecules with a phospholipid monolayer is proposed. In this model, an observed decrease of the lipid electron density in the protein presence is explained in terms of "holes" in the monolayer film caused by protein molecule adsorption.

  1. TOOKUIL: A case study in user interface development for safety code application

    SciTech Connect

    Gray, D.L.; Harkins, C.K.; Hoole, J.G.

    1997-07-01

    Traditionally, there has been a very high learning curve associated with using nuclear power plant (NPP) analysis codes. Even for seasoned plant analysts and engineers, the process of building or modifying an input model for present day NPP analysis codes is tedious, error prone, and time consuming. Current cost constraints and performance demands place an additional burden on today`s safety analysis community. Advances in graphical user interface (GUI) technology have been applied to obtain significant productivity and quality assurance improvements for the Transient Reactor Analysis Code (TRAC) input model development. KAPL Inc. has developed an X Windows-based graphical user interface named TOOKUIL which supports the design and analysis process, acting as a preprocessor, runtime editor, help system, and post processor for TRAC. This paper summarizes the objectives of the project, the GUI development process and experiences, and the resulting end product, TOOKUIL.

  2. Application of Laser-Generated Ion Beams for Isochoric Heating to Study Plasma Mix at Interfaces

    NASA Astrophysics Data System (ADS)

    Albright, B. J.; Fernández, J. C.; Bang, W.; Bradley, P. A.; Gautier, D. C.; Hamilton, C. E.; Palaniyappan, S.; Santiago Cordoba, M. A.; Vold, E. L.; Yin, L.; Hegelich, B. M.; Dyer, G.; Roycroft, R.

    2015-11-01

    The evolution and mixing of high-Z/low-Z interfaces in plasma media is of profound importance to high energy density physics and inertial fusion experiments. Recent experiments performed at the LANL Trident laser facility as part of the Plasma Interfacial Mix project have applied novel, laser-generated ion beams created under conditions of relativistic induced transparency to the heating of solid-density, multi-material targets isochorically and uniformly (over a few tens of ps), attaining plasma temperatures of several eV. Measurements have been made of the evolving plasma, including location of the material interface and the time-history of the temperature of the medium. Recent data and associated radiation hydrodynamic modeling from our Trident campaigns will be reported. Complementary kinetic simulations of interface evolution, showing anomalously rapid atomic mixing under conditions relevant to ICF experiments, will also be discussed. Work performed under the auspices of the U.S. DOE by the LANS, LLC, Los Alamos National Laboratory under Contract No. DE-AC52-06NA25396. Funding provided by the Los Alamos National Laboratory Directed Research and Development Program.

  3. First Principles Study on the Electronic Structure and Interface Stability of Hybrid Silicene/Fluorosilicene Nanoribbons

    NASA Astrophysics Data System (ADS)

    Jiang, Q. G.; Zhang, J. F.; Ao, Z. M.; Wu, Y. P.

    2015-10-01

    The interface stability of hybrid silicene/fluorosilicene nanoribbons (SFNRs) has been investigated by using density functional theory calculations, where fluorosilicene is the fully fluorinated silicene. It is found that the diffusion of F atoms at the zigzag and armchair interfaces of SFNRs is endothermic, and the corresponding minimum energy barriers are respectively 1.66 and 1.56 eV, which are remarkably higher than the minimum diffusion energy barrier of one F atom and two F atoms on pristine silicene 1.00 and 1.29 eV, respectively. Therefore, the thermal stability of SFNRs can be significantly enhanced by increasing the F diffusion barriers through silicene/fluorosilicene interface engineering. In addition, the electronic and magnetic properties of SFNRs are also investigated. It is found that the armchair SFNRs are nonmagnetic semiconductors, and the band gap of armchair SFNRs presents oscillatory behavior when the width of silicene part changing. For the zigzag SFNRs, the antiferromagnetic semiconducting state is the most stable one. This work provides fundamental insights for the applications of SFNRs in electronic devices.

  4. First Principles Study on the Electronic Structure and Interface Stability of Hybrid Silicene/Fluorosilicene Nanoribbons

    PubMed Central

    Jiang, Q. G.; Zhang, J. F.; Ao, Z. M.; Wu, Y. P.

    2015-01-01

    The interface stability of hybrid silicene/fluorosilicene nanoribbons (SFNRs) has been investigated by using density functional theory calculations, where fluorosilicene is the fully fluorinated silicene. It is found that the diffusion of F atoms at the zigzag and armchair interfaces of SFNRs is endothermic, and the corresponding minimum energy barriers are respectively 1.66 and 1.56 eV, which are remarkably higher than the minimum diffusion energy barrier of one F atom and two F atoms on pristine silicene 1.00 and 1.29 eV, respectively. Therefore, the thermal stability of SFNRs can be significantly enhanced by increasing the F diffusion barriers through silicene/fluorosilicene interface engineering. In addition, the electronic and magnetic properties of SFNRs are also investigated. It is found that the armchair SFNRs are nonmagnetic semiconductors, and the band gap of armchair SFNRs presents oscillatory behavior when the width of silicene part changing. For the zigzag SFNRs, the antiferromagnetic semiconducting state is the most stable one. This work provides fundamental insights for the applications of SFNRs in electronic devices. PMID:26496976

  5. Computational study of effect of water finger on ion transport through water-oil interface

    NASA Astrophysics Data System (ADS)

    Kikkawa, Nobuaki; Wang, Lingjian; Morita, Akihiro

    2016-07-01

    When an ion transports from water to oil through water-oil interface, it accompanies hydrated water molecules and transiently forms a chain of water, called "water finger." We thoroughly investigated the role of the water finger in chloride ion transport through water-dichloromethane interface by using molecular dynamics technique. We developed a proper coordinate w to describe the water finger structure and calculated the free energy landscape and the friction for the ion transport as a function of ion position z and the water finger coordinate w. It is clearly shown that the formation and break of water finger accompanies an activation barrier for the ion transport, which has been overlooked in the conventional free energy curve along the ion position z. The present analysis of the friction does not support the hypothesis of augmented local friction (reduced local diffusion coefficient) at the interface. These results mean that the experimentally observed rate constants of interfacial ion transfer are reduced from the diffusion-limited one because of the activation barrier associated to the water finger, not the anomalous local diffusion. We also found that the nascent ion just after the break of water finger has excessive hydration water than that in the oil phase.

  6. Computational study of effect of water finger on ion transport through water-oil interface.

    PubMed

    Kikkawa, Nobuaki; Wang, Lingjian; Morita, Akihiro

    2016-07-01

    When an ion transports from water to oil through water-oil interface, it accompanies hydrated water molecules and transiently forms a chain of water, called "water finger." We thoroughly investigated the role of the water finger in chloride ion transport through water-dichloromethane interface by using molecular dynamics technique. We developed a proper coordinate w to describe the water finger structure and calculated the free energy landscape and the friction for the ion transport as a function of ion position z and the water finger coordinate w. It is clearly shown that the formation and break of water finger accompanies an activation barrier for the ion transport, which has been overlooked in the conventional free energy curve along the ion position z. The present analysis of the friction does not support the hypothesis of augmented local friction (reduced local diffusion coefficient) at the interface. These results mean that the experimentally observed rate constants of interfacial ion transfer are reduced from the diffusion-limited one because of the activation barrier associated to the water finger, not the anomalous local diffusion. We also found that the nascent ion just after the break of water finger has excessive hydration water than that in the oil phase. PMID:27394116

  7. First Principles Study on the Electronic Structure and Interface Stability of Hybrid Silicene/Fluorosilicene Nanoribbons.

    PubMed

    Jiang, Q G; Zhang, J F; Ao, Z M; Wu, Y P

    2015-01-01

    The interface stability of hybrid silicene/fluorosilicene nanoribbons (SFNRs) has been investigated by using density functional theory calculations, where fluorosilicene is the fully fluorinated silicene. It is found that the diffusion of F atoms at the zigzag and armchair interfaces of SFNRs is endothermic, and the corresponding minimum energy barriers are respectively 1.66 and 1.56 eV, which are remarkably higher than the minimum diffusion energy barrier of one F atom and two F atoms on pristine silicene 1.00 and 1.29 eV, respectively. Therefore, the thermal stability of SFNRs can be significantly enhanced by increasing the F diffusion barriers through silicene/fluorosilicene interface engineering. In addition, the electronic and magnetic properties of SFNRs are also investigated. It is found that the armchair SFNRs are nonmagnetic semiconductors, and the band gap of armchair SFNRs presents oscillatory behavior when the width of silicene part changing. For the zigzag SFNRs, the antiferromagnetic semiconducting state is the most stable one. This work provides fundamental insights for the applications of SFNRs in electronic devices. PMID:26496976

  8. Eliminating unwanted nanobubbles from hydrophobic solid/liquid interfaces: a case study using magnetoelastic sensors.

    PubMed

    Feng, Xinjian; Roy, Somnath C; Grimes, Craig A

    2008-04-15

    Air bubbles are known to form at the liquid/solid interface of hydrophobic materials upon immersion in a liquid (Holmberg, M.; Kdühle, A.; Garnaes, J.; Mørch, K. A.; Boisen, A. Langmuir 2003, 19, 10510-10513). In the case of gravimetric sensors, air bubbles that randomly form at the liquid-solid interface result in poor sensor-to-sensor reproducibility. Herein a superhydrophilic ZnO nanorod film is applied to the originally hydrophobic surface of a resonance-based magnetoelastic sensor. The superhydrophilic coating results in the liquid completely spreading across the surface, removing unwanted air bubbles from the liquid/sensor interface. The resonance amplitude of uncoated (bare) and ZnO-modified sensors are measured in air and then when immersed in saline solution, ethylene glycol, or bovine blood. In comparison to the bare, hydrophobic sensors, we find that the standard deviation of the resonance amplitudes of the liquid-immersed ZnO-nanorod-modified sensors decreases substantially, ranging from a 27% decrease for bovine blood to a 67% decrease for saline. The strategy of using a superhydrophilic coating can be applied to other systems having similar interfacial problems. PMID:18307368

  9. Technical challenges in metatranscriptomic studies applied to the bacterial communities of freshwater ecosystems.

    PubMed

    Pascault, Noémie; Loux, Valentin; Derozier, Sandra; Martin, Véronique; Debroas, Didier; Maloufi, Selma; Humbert, Jean-François; Leloup, Julie

    2015-04-01

    Metatranscriptome analysis relates to the transcriptome of microbial communities directly sampled in the environment. Accessing the mRNA pool in natural bacterial communities presents some technical challenges such as the RNA extraction, rRNA depletion, and the choice of the high-throughput sequencing technique. The lack of technical details in scientific articles is a major problem to correctly obtained mRNA from a microbial community and thus the corresponding sequencing data. In our study, we present the methodological procedure that was developed in order to access to the metatranscriptome of the microbial communities during two cyanobacterial blooms successively occurring in a freshwater eutrophic lake. Each procedure step was detailed and discussed with regard to the choices and difficulties encountered and to the recent literature. Finally, the two major limits for metatranscriptomic approaches targeting bacterial communities from natural environments were (i) the removal of rRNA in order to increase the putative mRNA reads number after sequencing, and (ii) for most of the bacterial communities living in natural environments, the lack of reference genomes in databases that leads to the non-assignation of numerous reads. Once these challenges overcome, we managed to access putative mRNA of dominant species, i.e. cyanobacteria (from 6 to 72 % of mRNA assigned), and of the surrounding bacteria (from 1 to 5 % of mRNA assigned). PMID:25216965

  10. Effects of kinesthetic versus visual imagery practice on two technical dance movements: a pilot study.

    PubMed

    Girón, Elizabeth Coker; McIsaac, Tara; Nilsen, Dawn

    2012-03-01

    Motor imagery is a type of mental practice that involves imagining the body performing a movement in the absence of motor output. Dance training traditionally incorporates mental practice techniques, but quantitative effects of motor imagery on the performance of dance movements are largely unknown. This pilot study compared the effects of two different imagery modalities, external visual imagery and kinesthetic imagery, on pelvis and hip kinematics during two technical dance movements, plié and sauté. Each of three female dance students (mean age = 19.7 years, mean years of training = 10.7) was assigned to use a type of imagery practice: visual imagery, kinesthetic imagery, or no imagery. Effects of motor imagery on peak external hip rotation varied by both modality and task. Kinesthetic imagery increased peak external hip rotation for pliés, while visual imagery increased peak external hip rotation for sautés. Findings suggest that the success of motor imagery in improving performance may be task-specific. Dancers may benefit from matching imagery modality to technical tasks in order to improve alignment and thereby avoid chronic injury. PMID:22390952

  11. Analytical study of acousto/optical holography-interfacing methods for acoustical and optical holography NDT research

    NASA Technical Reports Server (NTRS)

    El-Sum, H. M. A.

    1976-01-01

    The international status of the art of acousto optical imaging techniques adaptable to nondestructive testing and, interfacing methods for acoustical and optical holography in nondestructive testing research are studied. Evaluation of 20 different techniques encompassed investigation of varieties of detectors and detection schemes, all of which are described and summarized. Related investigation is reported in an Appendix. Important remarks on image quality, factors to be considered in designing a particular system, and conclusions and recommendations are presented. Three bibliographies are included.

  12. Studies of the analyte-carrier interface in flow injection analysis. Final report, June 1, 1987--January 31, 1992

    SciTech Connect

    Brown, S.D.

    1992-12-31

    Chemical analysis in flowing solution is popular for automation of classical methods. However, most of the classical methods are not specific enough for direct multicomponent analysis of simple mixtures. This research project has the goals of study of rapid multicomponent analysis of transient species in flowing media, and investigations of chemical reactions at interfaces and of effects of competition on distribution of products from interfacial reaction. This report summarizes work done over the past 4.5 years; support has been terminated.

  13. A Phenomenological Study of the Metal-Oxide Interface: The Role of Catalysis in Hydrogen Production from Renewable Resources

    SciTech Connect

    Idriss, H.; Llorca, J; Chan, S; Blackford, M; Pas, S; Hill, A; Alamgir, F; Rettew, R; Petersburg, C; Barteau, M

    2008-01-01

    The truth about Cats: The metal-oxide interface of a Pd-Rh/CeO{sub 2} catalyst was studied in the context of developing active, selective and durable solid catalytic materials for the production of hydrogen from renewables. The presence of a stable contact between finely dispersed transition-metal clusters (Pd and Rh) on the nanoparticles of the CeO{sub 2} support leads to a highly active and stable catalyst for the steam reforming of ethanol.

  14. Case Study on Technical and Vocational Education in Japan. Case Studies on Technical and Vocational Education in Asia and the Pacific.

    ERIC Educational Resources Information Center

    Iwamoto, Muneharu

    In the course of Japan's economic progress, remarkable changes have occurred in the structure of industry and employment. Workers are in extremely short supply in such occupations as mining, manufacturing and construction, services, transportation and communication, sales, and professional and technical. On the basis of recommendations of the…

  15. The Development of Technical and Vocational Education for Vietnam--A Case Study in Quality Improvement. Case Studies on Technical and Vocational Education in Asia and the Pacific.

    ERIC Educational Resources Information Center

    Nguyen, Duong

    This report provides a general overview of technical and vocational education in Vietnam, with information on the country's economy, climate, population, and culture. It summarizes the history and present practices of these types of education in the country, and suggests measures to improve the quality of teachers and instructors. Some of the…

  16. The Development of Technical and Vocational Education in Malaysia--A Case Study in Quality Improvement. Case Studies on Technical and Vocational Education in Asia and the Pacific.

    ERIC Educational Resources Information Center

    Hee, Tieng Fok

    The economic profile of Malaysia has changed from an economy mainly based on agriculture and the production of tin ore to a more balanced economy with continuing growth in the manufacturing and industrial sectors. Educational programs need to be upgraded and improved, particularly the direction and development of technical and vocational education…

  17. Loofah sponge as an interface dressing material in negative pressure wound therapy: results of an in vivo study.

    PubMed

    Tuncel, Umut; Turan, Aydin; Markoc, Fatma; Erkorkmaz, Unal; Elmas, Cigdem; Kostakoglu, Naci

    2014-03-01

    Since the introduction of negative pressure wound therapy (NPWT), the physiological effects of various interface dressing materials have been studied. The purpose of this experimental study was to compare the use of loofah sponge to standard polyurethane foam or a cotton gauze sponge. Three wounds, each measuring 3 cm x 3 cm, were created by full-thickness skin excision on the dorsal sides of 24 New Zealand adult white rabbits. The rabbits were randomly divided into four groups of six rabbits each. In group 1 (control), conventional saline-moistened gauze dressing was provided and changed at daily intervals. The remaining groups were provided NPWT dressings at -125 mm Hg continuous pressure. This dressing was changed every 3 days for 9 days; group 2 was provided polyurethane foam, group 3 had conventional saline-soaked antimicrobial gauze, and group 4 had loofah sponge. Wound area measurements and histological findings (inflammation, granulation tissue, neovascularization, and reepithelialization) were analyzed on days 3, 6, and 9. Wound area measurements at these intervals were significantly different between the control group and study groups (P<0.05). Granulation and neovascularization scores were also significantly different between the control and treatment groups at day 3 (P=0.002). No differences in any of the healing variables studied were observed between the other three dressing materials. According to scanning electron microscopy analysis of the three interface materials, the mean pore size diameter of foam and gauze interface materials was 415.80±217.58 μm and 912.33±116.88 μm, respectively. The pore architecture of foam was much more regular than that of gauze. The average pore size diameter of loofah sponge was 736.83±23.01 μm; pores were hierarchically located--ie, the smaller ones were usually peripheral and larger ones werecentral. For this study, the central part of loofah sponge was discarded to achieve a more homogenous structure of

  18. WindPACT Turbine Design Scaling Studies Technical Area 1-Composite Blades for 80- to 120-Meter Rotor

    SciTech Connect

    Griffin, D.A.

    2001-04-30

    The United States Department of Energy (DOE) through the National Renewable Energy Laboratory (NREL) implemented the Wind Partnership for Advanced Component Technologies (WindPACT) program. As part of the WindPACT program, Global Energy Concepts, LLC (GEC), was awarded contract number YAM-0-30203-01 to examine Technical Area 1-Blade Scaling, Technical Area 2-Turbine Rotor and Blade Logistics, and Technical Area 3-Self-Erecting Towers. This report documents the results of GEC's Technical Area 1-Blade Scaling. The primary objectives of the Blade-Scaling Study are to assess the scaling of current materials and manufacturing technologies for blades of 40 to 60 meters in length, and to develop scaling curves of estimated cost and mass for rotor blades in that size range.

  19. Technical note: Detection of dimethylamine in the low pptv range using nitrate Chemical Ionization-Atmospheric Pressure interface-Time Of Flight (CI-APi-TOF) mass spectrometry

    NASA Astrophysics Data System (ADS)

    Simon, M.; Heinritzi, M.; Herzog, S.; Leiminger, M.; Bianchi, F.; Praplan, A.; Dommen, J.; Curtius, J.; Kürten, A.

    2015-12-01

    Amines are potentially important for atmospheric new particle formation and therefore the demand for highly sensitive gas phase amine measurements has emerged in the last several years. Nitrate Chemical Ionization Mass Spectrometry (CIMS) is routinely used for the measurement of gas phase-sulfuric acid in the sub-pptv range. Furthermore, Extremely Low Volatile Organic Compounds (ELVOCs) can be detected with a nitrate CIMS. In this study we demonstrate that a nitrate CIMS can also be used for the sensitive measurement of dimethylamine ((CH3)2NH, DMA) using the NO3-(HNO3)1-2(DMA) cluster ion signals. This observation was made at the CLOUD aerosol chamber, which was also used for calibration measurements. Good linearity between 0 and ~120 pptv of DMA as well as a sub-pptv detection limit of 0.7 pptv for a 10 min integration time are demonstrated at 278 K and 38 % RH.

  20. Georadar Study For Investigation of Hydro Technical Objects In Permafrost Area

    NASA Astrophysics Data System (ADS)

    Velikin, S. A.; Snegirev, A. M.

    The hydro technical engineering objects (HTIO) which are carried up in permafrost zone like Western Yakutia, are exposed to action of a different sort of the negative factors step-by-step resulting some of them in a labile state, down to catastrophic. To such negative factors it is necessary to refer abusing, refusals in operation of congeal- ing systems and error of design solutions based on poor bulk and quality of indis- pensable surveys in design and building phase. Owing to these circumstances for last 5-8 years on a number of hydro technical objects of Western Yakutia are observed thawing-filtration processes, are found out local filtration zones posing under threat their secure exploitation. The development of respective design solutions on security of stability requires conducting analysis of these objects. In these requirements the special significance is gained all-up geophysical monitoring studies permitting to trace a spatially - temporal variability of physical fields, reflecting variation of the structure and state of the basement of HTIO. and the more and more relevant role in these studies is gained with a georadar study. The georadar observations were carried out on Mirnii region ( Sakha-Yakutia) in a complex with electric-prospecting observations (NF) and temperature logging. The georadar SIR 2000 (production of the company GSSI, USA) with antennas 40, 200 MHz was applied. The data were processed with software packages RADAN (GSSI, USA) and RadExPro + (GSD Production, Russia). As a result of these observations the quite good correlation between applied geophysi- cal methods was established. The most interesting results of observations documented by excavation and visual observations will be presented in the report.