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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. 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…

  5. The chemistry of cyborgs--interfacing technical devices with organisms.

    PubMed

    Giselbrecht, Stefan; Rapp, Bastian E; Niemeyer, Christof M

    2013-12-23

    The term "cyborg" refers to a cybernetic organism, which characterizes the chimera of a living organism and a machine. Owing to the widespread application of intracorporeal medical devices, cyborgs are no longer exclusively a subject of science fiction novels, but technically they already exist in our society. In this review, we briefly summarize the development of modern prosthetics and the evolution of brain-machine interfaces, and discuss the latest technical developments of implantable devices, in particular, biocompatible integrated electronics and microfluidics used for communication and control of living organisms. Recent examples of animal cyborgs and their relevance to fundamental and applied biomedical research and bioethics in this novel and exciting field at the crossroads of chemistry, biomedicine, and the engineering sciences are presented. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. 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.

  7. Concurrent engineering technical interface process flow. Report of the CE Technical/Administrative Interface Task Group of the CALS/CE Industry Steering Group

    NASA Astrophysics Data System (ADS)

    1991-07-01

    A general guide to the components of the Department of Defense (DoD) and Industry needed to describe the technical interfaces required for implementing concurrent engineering is provided. These interfaces address the key components of design, manufacturing, and logistic support in an integrated environment. This document is intended to provide a transition structure for the other concurrent engineering task groups to build a more complete definition of the concurrent engineering process. The document addresses the technical interfaces of the government's acquisition process and does not attempt to define the business relationships or interfaces of administering the acquisition process.

  8. 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.

  9. United States Space Station technical and programmatic interfaces

    NASA Technical Reports Server (NTRS)

    Carlisle, Richard F.; Rice, William E.

    1987-01-01

    This paper describes the design of the U.S. Space Station and explains the control factors used for internal and external interfaces among the various government and contractor participants. It discusses the documentation of the U.S. Space Station Program including the Program Approval Document (PAD), the Program Plans (PPs), the Program Requirements Document (PRD), the Program Definition and Requirements Document (PDRD), the Level III project plans, and the Level III project design requirements documents. It discusses the relationship of Space Station documentation to the international Memoranda of Understanding (MOUs) and the Joint PP, PRD, and PDRD, the interrelationship of the Architectural Control Documents (ACDs), the Baseline Control Document (BCD), and the Interface Requirement Documents (IRDs) and Interface Control Documents (ICDs). Also included are the controlling functions of the various NASA and contractor participants and the international partners.

  10. 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…

  11. 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.

  12. Model study of protein unfolding by interfaces.

    PubMed

    Chakarova, S D; Carlsson, A E

    2004-02-01

    We study interface-induced protein unfolding on hydrophobic and polar interfaces by means of a two-dimensional lattice model and an exhaustive enumeration ground-state structure search, for a set of model proteins of length 20 residues. We compare the effects of the two types of interfaces, and search for criteria that influence the retention of a protein's native-state structure upon adsorption. We find that the unfolding proceeds by a large, sudden loss of native contacts. The unfolding at polar interfaces exhibits similar behavior to that at hydrophobic interfaces but with a much weaker interface coupling strength. Further, we find that the resistance of proteins to unfolding in our model is positively correlated with the magnitude of the folding energy in the native-state structure, the thermal stability (or energy gap) for that structure, and the interface energy for native-state adsorption. We find these factors to be of roughly equal importance.

  13. Model study of protein unfolding by interfaces

    NASA Astrophysics Data System (ADS)

    Chakarova, S. D.; Carlsson, A. E.

    2004-02-01

    We study interface-induced protein unfolding on hydrophobic and polar interfaces by means of a two-dimensional lattice model and an exhaustive enumeration ground-state structure search, for a set of model proteins of length 20 residues. We compare the effects of the two types of interfaces, and search for criteria that influence the retention of a protein’s native-state structure upon adsorption. We find that the unfolding proceeds by a large, sudden loss of native contacts. The unfolding at polar interfaces exhibits similar behavior to that at hydrophobic interfaces but with a much weaker interface coupling strength. Further, we find that the resistance of proteins to unfolding in our model is positively correlated with the magnitude of the folding energy in the native-state structure, the thermal stability (or energy gap) for that structure, and the interface energy for native-state adsorption. We find these factors to be of roughly equal importance.

  14. Technical design and first clinical application of the generic HIPIN HIS/RIS-PACS interface

    NASA Astrophysics Data System (ADS)

    Ottes, Fenno P.; Martens, Frans J.; Schulz, Carl A.; Toussaint, Pieter J.; van den Broeck, Renaat; Rechid, Renas; Bakker, Albert R.

    1994-05-01

    HIS/RIS-PACS interfaces are inevitably very complex due to the large differences between HIS/RIS and PACS. Furthermore, because of the high degree of mutual variation among HIS/RIS system and among PACS systems, the interface must be different for each combination of HIS/RIS with PACS. To solve this problem, a generic HIS/RIS-PACS interface has been designed and realized within the scope of the EurIPACS/HIPIN topic. The internal architecture of the HIPIN interface has been designed into a common part, which schedules and processes the messages, and specific adapters for each of the connected systems, which match the communication profile and the message syntax of the system to which it belongs. The applicability of this HIPIN interface both in technical and in clinical aspect is being demonstrated by testing and by using the HIPIN interface at two hospitals, namely the Free University Hospital in Brussels and the Philipps University Hospital in Marburg.

  15. Second harmonic studies of liquid interfaces

    SciTech Connect

    Ong, S.

    1992-12-31

    This thesis reports on experimental studies of kinetics and equilibria at liquid interfaces using the technique of Second Harmonic Generation (SHG). In the first part, SHG was used to study the kinetics of adsorption of p-nitrophenol at the air/water interface of a flowing liquid jet. Measurements of the SH signal strength and the polarization of the SH light at various distances (times) along the jet axis yield information about the development of the density and orientation of p-nitrophenol at the air/water interface. The kinetics of adsorption was interpreted in terms of the Langmuir theory and was found to be consistent with this model. The free energy of adsorption obtained from the jet experiments was found to be the same as that obtained from static (equilibrium) experiments. The orientation of p-nitrophenol at the jet air/solution interface was the same as for the static (equilibrium) interface,which indicates that orientational equilibrium was rapidly achieved. It was also found that adsorption of nitrophenol to the air/water interface is not diffusion controlled, but rather is kinetically controlled by a barrier. SHG was then used to probe the silica/water interface.

  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. 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

  18. 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.

  19. Vocational-Technical Education Interface with Ohio's High Technology Business and Industrial Sector. Final Report.

    ERIC Educational Resources Information Center

    McCormick, Robert W.

    This study explored the relationship of vocational-technical educational institutions in Ohio with business and industry using high-technology applications. The study attempted to determine what high-technology applications will be adopted by Ohio's business and industry in the next 5 years, what experience the schools have had in working with…

  20. 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.

  1. Solar thermochemical process interface study

    NASA Astrophysics Data System (ADS)

    1984-02-01

    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.

  2. Tape/head interface study

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Existing high energy tapes, high track density heads, and transport guidance techniques were evaluated and characterized to enable these technologies to be employed in future spacecraft recorders with high confidence. The results of these study efforts demonstrated tracking accuracy tape and head density that will support spacecraft recorders with data rates of a minimum of 150 Mbps and storage capacities ranging from 10 to the 10th to 10 to the 11th bits. Seven high energy tapes of either .25 in width, 1.00 in width, or both, were tested. All tapes were tested at the same speed (30 ips) and the same packing density (33 KBI). The performance of all 1 in tapes was considered superior.

  3. 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.

  4. TECHNICAL NOTE: Chemical analysis of bonded and debonded silicon-glass interfaces

    NASA Astrophysics Data System (ADS)

    Visser, M. M.; Plaza, J. A.; Wang, D. T.; Hanneborg, A. B.

    2001-09-01

    We report on the nature of the interface of anodically bonded glass wafers (Pyrex 7740, Hoya SD-2) and silicon wafers, after having reversed the voltage across the wafer couples. The reaction products and defects discovered at the interface of the wafers are studied with scanning electron microscopy, electron dispersive x-ray spectroscopy and with an electron microprobe. An accumulation, especially of sodium, is found to be closely related to the presence of defects appearing as brown/yellow-brown spots and cracks. Gradients in potassium and zinc concentrations are also observed in regions containing defects. Some of the processes that are believed to take place in the interface region are discussed. ane{abstract

  5. 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.

  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. '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.…

  8. 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…

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. Crew interface definition study, phase 1

    NASA Technical Reports Server (NTRS)

    Callihan, J. C.; Kraemer, J. W.; Alles, J. A.

    1971-01-01

    The timeline analysis of the Shuttle orbiter missions which was conducted in the Phase I Crew Interface Definition Study and the requirements for the man-in-the-loop simulation study are presented. Mission definitions and objectives are presented as they relate to various Shuttle Orbiter missions. The requirements for crew participation and the information required by the crew are discussed, and finally the rationale behind the display concept and calling procedures is given. The simulation objectives, the simulation mechanization, including a detailed presentation of the display and control concept, the simulator test plan and the results are discussed.

  14. Scanning tunneling microscopy and spectroscopy of ceramic interfaces. Technical report to the Department of Energy, Office of Basic Energy Sciences

    SciTech Connect

    Bonnell, Dawn A.

    2001-03-26

    This document reports advances made on the Penn DOE project focused on using scanning probe measurements at individual interfaces to relate nanometer scale property variation to behavior in ceramic systems. The report body summarizes annual technical accomplishments. (The details are provided in papers referenced in the appendix.) Related collaborative interactions are described, after which the project productivity is reported in terms of human resource development and publications.

  15. 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.

  16. Experimental Study of Electronic States at Interfaces.

    DTIC Science & Technology

    1987-01-01

    relaxation time of 4 to 20 conduction band back to the bound states is long nsec is obtained, inspection of the phonon density-of- enough then the Is...AiBI 929 EXPERIMENTAL STUDY OF ELECTRONIC STATES AT INTERFACES 1/1 STATE PNVSICS A J SIEVERS 1987 AFOSR-TR-87-0851 U LSIFIE D AFOSR-8885 - FG 2112 L...NAME OF MONITORING ORGANIZATION i (~able) AORN Cornell University 9 e) AFOSR/NE 6c. ADDRESS (City, State , and ZIP Code) 7b ADDRESS (City, State , and

  17. Femtosecond Studies of Electrons at Interfaces

    NASA Astrophysics Data System (ADS)

    Harris, Charles

    2000-03-01

    Binding energies and ultrafast relaxation dynamics of image electrons reflect the nature of the electronic interaction with both the substrate and the adsorbed layer[1,2]. We demonstrate that a positive(attractive) affinity materials, such as Xe overlayers, lead to quantum well states at the interface. Negative(repulsive) affinity materials, such a n-alkane overlayers, present a tunneling barrier that dominates the energies and lifetimes of the image electrons. With the time- and angle-resolved two-photon photoemission technique(TPPE), it is possible to directly observe the dynamics of interfacial electrons with specific energy and parallel momentum. Oscillation in the lifetime of image state electrons as a function of Xe layer thickness is attributed to a quantum size effect and the formation of quantum wells at the Xe/Ag(111) interface[3]. Binding energy measurements as a function of Xe layer thickness in combination with parallel dispersion measurements allow the mapping of the three dimensional electronic structure of bulk Xe. At the n-alkane/Ag(111) interface, image electrons become spatially localized and self-trap into a small polaron state within a few hundred femtosecond[4]. The energy dependence of the self-trapping rate has been modeled with a theory analogous to electron transfer theory. Finally, the immediate extension of this research to study other electron dynamic processes, such as two dimensional electron solvation at interfaces, will be discussed. [1] Fauster, T.; Steinmann, W. Two-Photon Photoemission Spectroscopy of Image States. In Photonic Probes of Surfaces; Halevi, P., Ed.; Elsevier: Amsterdam, 1995; pp. 346-411. [2] Harris, C.B.; Ge, N.-H.; Lingle, Jr., R.L.; McNeill, J.D.; Wong, C.M. Annu. Rev. Phys. Chem. 1997, 48, 711. [3] McNeill, J.D.; Lingle, R.L.,Jr.; Ge, N.-H.; Wong, C.M.; Jordan, R.E.; Harris, C.B. Phys. Rev. Lett. 1997, 79, 4645. [4] Ge, N.-H.; Wong, C.M.; Lingle, R.L., Jr.; McNeill, J.D.; Gaffney, K.J.; Harris, C.B. Science 1998

  18. 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.

  19. Study of Behavior of Sterols at Interfaces

    NASA Technical Reports Server (NTRS)

    Klein, P. D.; Knight, J. C.; Szczepanik, P. A.

    1968-01-01

    Behavior of sterols and sterol acetates on various types of interfaces indicates that the function of a sterol depends upon a surface orientation and surface energy of the interface. Column-chromatographic techniques determine the retention volume of various sterols under standard conditions.

  20. Study on Geoacoustics Interface Wave Scattering Characteristic

    NASA Astrophysics Data System (ADS)

    Guo, Xinyi; Ma, Li

    2010-09-01

    This paper introduces the propagation characterization of interface waves in elastic half space. In a layered medium, frequency dispersion exists and propagation models of interface waves can be researched using mode analysis. For a typical layered structure model, the propagation modes of interface waves can be calculated and the Green's function can be obtained using propagation modes. In practical problems, there are buried objects in the medium. An interface wave scattering integral equation is derived, and scattering interface wave fields can be simulated by computer. For checking this arithmetic, the scattering displacement field can be calculated using the first mode of an interface wave. The convergence rapidity of the method has been proved to be very high by some practical examples, and the scattering strength can be obtained simultaneously. Sometimes, there are multiple objects buried in the medium, and the interface wave scattering integral equation can be spread into calculation of a multi-objects scattering problem by the integral equation of the scattering elastic wave field associated with multi-inhomogeneities. In this paper, the high mode scattering of an interface wave can be calculated also. In order to achieve the detection buried objects using interface wave, there is an experiment for verifying this method. In this experiment, the interface wave signal extraction, propagation velocity, propagation attenuation, and several other aspects are analyzed. The time difference between direct wave and echo wave in the received signal can be obtained according to the geometric relationship of buried objects, source and geophone array locations. The echo signal exists in the received signal.

  1. [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).

  2. AD Hoc Study on Human Robot Interface Issues

    DTIC Science & Technology

    2002-09-01

    ARMY SCIENCE BOARD AD HOC STUDY ON HUMAN ROBOT INTERFACE ISSUES FINAL REPORT SEPTEMBER 2002 Distribution: Approved for...conclusions contained in this report are those of the 2002 Ad Hoc Study Panel on “Human- Robot Interface Issues” and do not necessarily reflect the official...DATES COVERED Army Science Board – 2002 Ad Hoc Study 4. TITLE AND SUBTITLE AD HOC STUDY ON HUMAN ROBOT INTERFACE ISSUES 6. AUTHOR(S) Study

  3. Web-Based Interactive Electronic Technical Manual (IETM) Common User Interface Style Guide, Version 2.0

    DTIC Science & Technology

    2003-07-01

    at various change levels: Chnglevel “delete” “add” Output 0 Look at the spoon 1 Spoon Look at the *** 2 Moon Look at the moon 3 Moon Loon ...Look at the loon 3-32 WEB-BASED INTERACTIVE ELECTRONIC TECHNICAL MANUAL COMMON USER INTERFACE STYLE GUIDE Version 2.0 July 2003 Example of...moon Look at the loon Look at the loon Look at the lagoon. 3.4.2 Re-purposing Data and Hardcopy Output The data within the IETM should be

  4. Hypervelocity Impact on Interfaces: A Molecular-Dynamics Simulations Study

    NASA Astrophysics Data System (ADS)

    Bachlechner, Martina E.; Owens, Eli T.; Leonard, Robert H.; Cockburn, Bronwyn C.

    2008-03-01

    Silicon/silicon nitride interfaces are found in micro electronics and solar cells. In either application the mechanical integrity of the interface is of great importance. Molecular-dynamics simulations are performed to study the failure of interface materials under the influence of hypervelocity impact. Silicon nitride plates impacting on silicon/silicon nitride interface targets of different thicknesses result in structural phase transformation and delamination at the interface. Detailed analyses of atomic velocities, bond lengths, and bond angles are used to qualitatively examine the respective failure mechanisms.

  5. Bachelor Studies in the Czech Technical Universities.

    ERIC Educational Resources Information Center

    Polak, Jaromir

    Universities are the highest level of the Czech school education system, as well as important scientific institutions that are granted full autonomy under the law. There are five technical universities and one military school with technical courses in the Czech Republic. Until the 1990s, the universities had provided only the five years magister…

  6. 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.

  7. 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.

  8. 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.

  9. 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…

  10. Space station resistojet system requirements and interface definition study

    NASA Technical Reports Server (NTRS)

    Heckert, Bruce J.

    1987-01-01

    Preliminary resistojet design requirements were established based on initial technical requirements imposed by the results of NASA and Rocketdyne studies. The requirements are directed toward long life, simplicity, flexibility, and commonality with other space station components. The resistojet assembly is comprised of eight resistojets, fluid components downstream of the waste fluid storage system, a power controller, structure, and shielding. It consists of two identical subassemblies, one of which is redundant. Each subassembly consists of four 500-W resistojets, series redundant latch values, a power controller, a water vaporizer, two pressure regulators, filters, check valves, disconnects, fluid tubing, and electrical cables. All components are packaged at the end of the stinger aft of the JEM and Columbus modules. Different flow and power control methods were studied. A constant inlet pressure and a two-power setting controller were tentatively selected based on simplicity and reasonably high specific impulse for the range of waste gas compositions that are anticipated. The constant pressure is supplied by pressure regulators. The two set point power control includes individual power supplies to each resistojet heater and water vaporizer. An embedded data processor, a multiplexer-demultiplexer, and a network interface unit that are standard space station components are included in the power controller. The total dry weight of the resistojet assembly is approximately 172 lb. The total cost for design, development, test, evaluation, qualification, and flight hardware is estimated to be $16 million.

  11. Space station resistojet system requirements and interface definition study

    NASA Technical Reports Server (NTRS)

    Heckert, Bruce J.

    1987-01-01

    Preliminary resistojet design requirements were established based on initial technical requirements imposed by the results of NASA and Rocketdyne studies. The requirements are directed toward long life, simplicity, flexibility, and commonality with other space station components. The resistojet assembly is comprised of eight resistojets, fluid components downstream of the waste fluid storage system, a power controller, structure, and shielding. It consists of two identical subassemblies, one of which is redundant. Each subassembly consists of four 500-W resistojets, series redundant latch values, a power controller, a water vaporizer, two pressure regulators, filters, check valves, disconnects, fluid tubing, and electrical cables. All components are packaged at the end of the stinger aft of the JEM and Columbus modules. Different flow and power control methods were studied. A constant inlet pressure and a two-power setting controller were tentatively selected based on simplicity and reasonably high specific impulse for the range of waste gas compositions that are anticipated. The constant pressure is supplied by pressure regulators. The two set point power control includes individual power supplies to each resistojet heater and water vaporizer. An embedded data processor, a multiplexer-demultiplexer, and a network interface unit that are standard space station components are included in the power controller. The total dry weight of the resistojet assembly is approximately 172 lb. The total cost for design, development, test, evaluation, qualification, and flight hardware is estimated to be $16 million.

  12. GUIDON-WATCH: A Graphic Interface for Viewing a Knowledge-Based System. Technical Report #14.

    ERIC Educational Resources Information Center

    Richer, Mark H.; Clancey, William J.

    This paper describes GUIDON-WATCH, a graphic interface that uses multiple windows and a mouse to allow a student to browse a knowledge base and view reasoning processes during diagnostic problem solving. The GUIDON project at Stanford University is investigating how knowledge-based systems can provide the basis for teaching programs, and this…

  13. 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.

  14. Numerical Modelling of Subduction Plate Interface, Technical Advances for Outstanding Questions

    NASA Astrophysics Data System (ADS)

    Le Pourhiet, L.; Ruh, J.; Pranger, C. C.; Zheng, L.; van Dinther, Y.; May, D.; Gerya, T.; Burov, E. B.

    2015-12-01

    The subduction zone interface is the place of the largest earthquakes on earth. Compared to the size of a subduction zone itself, it constitutes a very thin zone (few kilometers) with effective rheological behaviour that varies as a function of pressure, temperature, loading, nature of the material locally embedded within the interface as well as the amount of water, melts and CO2. Capturing the behaviour of this interface and its evolution in time is crucial, yet modelling it is not an easy task. In the last decade, thermo-mechanical models of subduction zone have flourished in the literature. They mostly focused on the long-term dynamics of the subduction; e.g. flat subduction, slab detachment or exhumation. The models were validated models against PTt path of exhumed material as well as topography. The models that could reproduce the data all included a mechanically weak subduction channel made of extremely weak and non cohesive material. While this subduction channel model is very convenient at large scale and might apply to some real subduction zones, it does not capture the many geological field evidences that point out the exhumation of very large slice of almost pristine oceanic crust along localised shear zone. Moreover, modelling of sismological and geodetic data using short term tectonic modelling approach also point out that large localised patches rupture within the subduction interface, which is in accordance with geological data but not with large-scale long-term tectonic models. I will present how high resolution models permit to produce slicing at the subduction interface and give clues on how the plate coupling and effective location of the plate interface vary over a few millions of year time scale. I will then discuss the implication of these new high-resolution long-term models of subduction zone on earthquake generation, report progress in the development of self-consistent thermomechanical codes which can handle large strain, high resolution

  15. 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.

  16. Ab Initio Studies of Surfaces and Interfaces

    NASA Astrophysics Data System (ADS)

    Garrity, Kevin F.

    2011-12-01

    Over the past 50 years, our ability to design and fabricate materials and devices with ever-smaller components has improved to the point that many technologies are crucially dependent on surfaces and interfaces. As this process continues, the atomic details of these surfaces and interfaces will take on increasing importance, both in understanding the behavior of existing structures as well as proposing and testing new materials and devices. First principles techniques are especially well-suited for exploring these systems, as they have the predictive capability required to understand the new phenomena which emerge at atomic length scales. In this work, we use first principles density functional theory to explore the properties of a variety of interesting surfaces and interfaces. First, we consider the thermodynamics and kinetics of Sr and La deposition on semiconductor surfaces, which is the first step in epitaxial oxide growth on semiconductors. Using this knowledge, we propose a method for growing LaAlO3 on epitaxially on Si. In addition, we explore the surface chemistry of a ferroelectric (PbTiO3) as a function a polarization in order to understand its applications to advanced catalysis. Finally, we investigate the coupling of phonons through an epitaxial interface between SrTiO3 and La 1-xSrxMnO 3, where an interfacial coupling of atomic motion is used to dynamically modulate the conductivity of a La1-xSr xMnO3 thin film.

  17. 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.

  18. Study of gelled LNG. Final technical report

    SciTech Connect

    Rudnicki, M I; Cabeal, J A; Hoffman, L C; Newton, R A; Schaplowsky, R K; Vander Wall, E M

    1980-01-01

    Research involved the characterization of gelled LNG (GELNG) with respect to process, flow, and use properties and an examination of the degree of safety enhancement attainable by gelation. The investigation included (1) an experimental examination of gel properties and gel safety characteristics as well as (2) an analytical study involving the economics and preliminary design of an industrial scale gelation system. The safety-related criterion for successful application of gelled LNG is the substantial reduction of the Maximum Distance to the Lower Flammability Limit, MDLFL. This will be achieved by first, gel-inhibition of the hydrodynamic pooling and spreading of the spill, and second, the suppressed thermal transport properties of the GELNG relative to those of LNG. The industrial scale gelation study evaluated a design capable of producing 11,000 gallons (LNG tank truck) of gel in two hours. The increased cost of gelation using this equipment was estimated at $0.23/10/sup 6/ Btu for plants with liquefaction facilities. The technical results of this study are supportive of the conclusion that gelation of LNG will reduce, relative to ungelled LNG, the hazard associated with a given size spill. Parameters of interest to the LNG facility operator (such as pumpability) are not significantly affected by gelation, and the impact on LNG delivery cost appears to be small, about 5%. Thus, the initial assumption that gelation would provide a practical means to enhance safety is supported by the results of this study. Larger scale, comparative spill tests of LNG and GELNG are now required to confirm the safety aspects of use of the gelled material.

  19. Analysis of the Data From a Technical Processing Cost Study.

    ERIC Educational Resources Information Center

    Rocke, Hans Joachim

    This study was conducted to analyze and summarize raw data obtained from a 1972 study: "Report on a Cost Study of Specific Technical Processing Activities of the California State University and College Libraries" with the hypothesis that the cost of technical processes increases as the production volume both rises above and falls below…

  20. Photovoltaic utility/customer interface study

    NASA Astrophysics Data System (ADS)

    Eichler, C. H.; Hayes, T. P.; Matthews, M. M.; Wilraker, V. F.

    1980-12-01

    The technical, economic, and legal and regulatory issues of interconnecting small, privately-owned, on-site photovoltaic generating systems to an electric utility are addressed. Baseline residential, commercial and industrial class photovoltaic systems were developed. Technical issues of concern affecting this interconnection were identified and included fault protection, undervoltage protection, lamp flicker, revenue metering, loss of synchromism, electrical safety, prevention of backfeeding a de-energized utility feeder, effects of on-site generation on utility relaying schemes, effects of power conditioner harmonic distortion on the electric utility, system isolation, electromagnetic interference and site power factor as seen by the utility. Typical interconnection wiring diagrams were developed for interconnecting each class of baseline photovoltaic generating system.

  1. 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.

  2. Study of the Al/graphite interface

    NASA Astrophysics Data System (ADS)

    Lu, Hua; Shen, Dian-hong; Deng, Xin-fa; Xue, Qi-kun; Froumin, N.; Polak, M.

    2001-09-01

    Thin Al films with a thickness of 20-30nm were prepared by ultra-high vacuum deposition of Al onto a graphite surface parallel to a (0001) basal plane. The samples were annealed up to 1070K. X-ray photoelectron spectroscopy analysis has shown that for temperatures just higher than 770K, a little carbide occurs in the Al film and only an Al-C phase is present at the Al/graphite interface. After annealing at 970K, the Al4C3 phase can be observed and the binding energy of the Al2p electrons increases continuously from 72.7 to 74.2eV with increasing temperature up to 1070K. Auger electron spectroscopy depth profiles are measured to investigate the phases existing in the Al film as well as at the Al/graphite interface. It is found that the Al4C3 phase at the interface is the final product of a series of Al carbides from the interfacial reaction between Al and graphite.

  3. Technical communication in aeronautics - Results of an exploratory study

    NASA Technical Reports Server (NTRS)

    Pinelli, Thomas E.; Glassman, Myron; Oliu, Walter E.; Barclay, Rebecca O.

    1989-01-01

    A study was undertaken that explored several aspects of technical communications in aeronautics. The study utilized survey research. A self-administered mail questionnaire was sent to 2,000 randomly selected members of the American Institute of Aeronautics and Astronautics (AIAA) in the U.S. with academic, government, or industrial affiliations. Six hundred and six (606) usable questionnaires were received. The findings add considerable information to the knowledge of technical communications among aeronautical engineers and scientists; reinforce some of the conventional wisdom about technical communications and question other widely-held notions; and hold significant implications for technical communicators, information managers, research and development managers, and curriculum developers.

  4. 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.

  5. Preliminary study of ceramic-metal interface in thermal boundaries

    NASA Astrophysics Data System (ADS)

    Tremouilles, G.; Derep, J. Luc

    1987-10-01

    The interface of yttrium doped zircon ceramic on NiCrAlY alloy is studied. The different phases in the zircon are examined with electron microscopy. The presence of alumina in the interface is demonstrated. The possibility of damaging the NiCrAlY substrate when using a plasma gun is discussed.

  6. 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…

  7. 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…

  8. 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…

  9. 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…

  10. Specialized Technical Assistance in Studies of Microgravity

    NASA Technical Reports Server (NTRS)

    Keshock, Edward G.

    1997-01-01

    Technical assistance was provided in connection with three projects, namely: (1) Capillary Heat Transfer (CHT) Glovebox Experiment, (2) Technological Evaluation of the Microgravity Isolation Mount (MIM) Glovebox Experiment, and (3) Two-Phase Annular Flow in Helical Coil Flow Channels in a Reduced Gravity Environment.

  11. 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.

  12. Technical communication: An initial evaluation of a novel anesthetic scavenging interface.

    PubMed

    Barwise, John A; Lancaster, Leland J; Michaels, Damon; Pope, Jason E; Berry, James M

    2011-11-01

    Waste anesthetic gas scavenging technology has not changed appreciably in the past 30 years. Open reservoir systems entrain high volumes of room air and dilute waste gases before emission into the atmosphere. This process requires a large vacuum pump, which is both costly to install and, although efficient, operates continuously and at near-full capacity. In an era of increasing energy costs and environmental awareness, carbon footprint reduction is a priority and a more efficient system of safely scavenging waste anesthetic gases is desirable. We tested a low-flow scavenger interface to evaluate the potential for cost and energy savings. The use of this interface in a suite of 4 operating rooms reduced scavenging flow from a constant 37 L/min to a value equal to the fresh gas flow (usually 2 L/min) for each anesthesia machine. Using the ventilator increased this flow by approximately 6 L/min because of the exhaust of ventilator drive gas into the scavenging circuit. Daytime workload of the central vacuum pump decreased from 92% to 12% (expressed as duty cycle). The new system produces energy savings and may increase vacuum pump lifespan.

  13. Tailored interfaces for metal-matrix composites-fundamental considerations. Final technical report, 1 October 1988-30 November 1992

    SciTech Connect

    Fine, M.E.; Weertman, J.R.

    1993-01-28

    The objective of this research was to investigate the interface properties of successful metal matrix composites. Thermodynamic stability of the interface and the phases in the composite, nature of the bonding across the interface, and the energy and structure of the interface were studied. With TiC dispersed in Al prepared by the XD process, atomic resolution electron microscopy showed a sharp interface with large areas of partial coherence. The Al-TiC composite is remarkably ductile even at 15 vol.% TiC loading. This attributed to the ability of the Al to recrystallize at the interface forming semicoherent boundaries and to a high level of metallic binding between Al and Ti in TiC. On holding at 640 C the kinetics of the reaction, 13Al + 3TiC - Al4C3 + 3Al3Ti, is rapid enough to be observed. This reaction leads to a substantial increase in strength and modulus but a reduction in ductility. Like steel, parts could be formed in the ductile state and then heat treated to increase hardness and modulus. At still higher temperatures, Al and TiC are the thermodynamically stable phases so no reaction occurs. Four Mg alloy matrix composites were received from Dow Chemical Corp.: Mg-6% Zn with SiC, Mg-3% Ce-l% Mn with SiC, Mg-9% Al-l% Zn with SiC, and Mg-9% Al-l% Zn with A2O3. All particle matrix interfaces appeared to be incoherent.

  14. 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…

  15. 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.…

  16. 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…

  17. 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.…

  18. Computational Studies of Protein-Protein Interface Designs

    NASA Astrophysics Data System (ADS)

    Gaines, Jennifer; O'Hern, Corey; Regan, Lynne

    We implement a hard-sphere model for amino acid structure to study natural and designed protein-protein interfaces. Current computational methods have found limited success in designing novel interfaces and resorted to implementing several rounds of experimental mutation and selection to achieve successful designs. Here, we show that the hard-sphere model can recapitulate the side chain dihedral angle distributions for amino acids at natural protein-protein interfaces. In addition, we calculate the packing fraction in naturally occurring interfaces and find that it is comparable to dense random packing in protein cores. We then evaluate a number of successful and unsuccessful prior computational designs in terms of the number of allowed side chain dihedral angle conformations and the packing fraction of residues at the interface.

  19. 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

  20. 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.

  1. 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.

  2. Assessing the Plasma-Liquid Interface Using Single Bubble Studies

    NASA Astrophysics Data System (ADS)

    Foster, John; Sagadevan, Athena; Gucker, Sarah

    2014-10-01

    Interaction physics and chemistry between a plasma in contact with liquid water occurs at the interface. Energy transport as well as radical species production occurs in this region. An understanding of the physical processes occurring in this region is key to elucidating the effect that plasma has on water chemistry well beyond the interface. Such an understanding has implications in application areas such as plasma medicine and water purification. Here, we present preliminary results from a 2-D system aimed at elucidating the plasma-liquid interface through the study of the interfacial response under the influence of plasma produced in a single, trapped bubble. The spatial extent and associated reactivity of this active layer associated with the interface region is interrogated with chemical probes and optical imaging. Results from these studies are presented. This work is supported by NSF CBET 1336375.

  3. 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.

  4. Do technical skills correlate with non-technical skills in crisis resource management: a simulation study.

    PubMed

    Riem, N; Boet, S; Bould, M D; Tavares, W; Naik, V N

    2012-11-01

    Both technical skills (TS) and non-technical skills (NTS) are key to ensuring patient safety in acute care practice and effective crisis management. These skills are often taught and assessed separately. We hypothesized that TS and NTS are not independent of each other, and we aimed to evaluate the relationship between TS and NTS during a simulated intraoperative crisis scenario. This study was a retrospective analysis of performances from a previously published work. After institutional ethics approval, 50 anaesthesiology residents managed a simulated crisis scenario of an intraoperative cardiac arrest secondary to a malignant arrhythmia. We used a modified Delphi approach to design a TS checklist, specific for the management of a malignant arrhythmia requiring defibrillation. All scenarios were recorded. Each performance was analysed by four independent experts. For each performance, two experts independently rated the technical performance using the TS checklist, and two other experts independently rated NTS using the Anaesthetists' Non-Technical Skills score. TS and NTS were significantly correlated to each other (r=0.45, P<0.05). During a simulated 5 min resuscitation requiring crisis resource management, our results indicate that TS and NTS are related to one another. This research provides the basis for future studies evaluating the nature of this relationship, the influence of NTS training on the performance of TS, and to determine whether NTS are generic and transferrable between crises that require different TS.

  5. WITHDRAWN: Axisymmetric Adaptive Drop/Interface Impacting Study

    NASA Astrophysics Data System (ADS)

    Zheng, Xiaoming; Lowengrub, John; Cristini, Vittorio

    2005-11-01

    The impact of a drop upon an interface is studied using an axisymmetric adaptive level-set/finite element method. Under certain conditions, the drop will rebound off the interface before breaking through. The drop fluid and the fluid below the interface are identical. We characterize the behavior in terms of the relevant nondimensional parameters: the Reynolds number, the Weber number, and the viscosity and density ratios of the fluid components. One of the primary difficulties in performing numerical simulations of such flows is the accurate resolution of the lubrication forces that arise in the near contact region between the drop and interface. To overcome this difficulty, we use a spatially and temporally adaptive mesh together with a new, stable and accurate projection method for the Navier-Stokes equations and a mass-conserving level-set algorithm for capturing the motion of the drop and interface (J. Comp. Phys., v. 208, 2005). We validate our algorithm by successfully matching the recent experimental results on drop/interface impact by Mohamed-Kassim and Longmire (Phys. Fluids, v. 15, 2003).

  6. Technical Note: Dose effects of 1.5 T transverse magnetic field on tissue interfaces in MRI-guided radiotherapy.

    PubMed

    Chen, Xinfeng; Prior, Phil; Chen, Guang-Pei; Schultz, Christopher J; Li, X Allen

    2016-08-01

    The integration of MRI with a linear accelerator (MR-linac) offers great potential for high-precision delivery of radiation therapy (RT). However, the electron deflection resulting from the presence of a transverse magnetic field (TMF) can affect the dose distribution, particularly the electron return effect (ERE) at tissue interfaces. The purpose of the study is to investigate the dose effects of ERE at air-tissue and lung-tissue interfaces during intensity-modulated radiation therapy (IMRT) planning. IMRT and volumetric modulated arc therapy (VMAT) plans for representative pancreas, lung, breast, and head and neck (HN) cases were generated following commonly used clinical dose volume (DV) criteria. In each case, three types of plans were generated: (1) the original plan generated without a TMF; (2) the reconstructed plan generated by recalculating the original plan with the presence of a TMF of 1.5 T (no optimization); and (3) the optimized plan generated by a full optimization with TMF = 1.5 T. These plans were compared using a variety of DV parameters, including V100%, D95%, DHI [dose heterogeneity index: (D20%-D80%)/Dprescription], Dmax, and D1cc in OARs (organs at risk) and tissue interface. All the optimizations and calculations in this work were performed on static data. The dose recalculation under TMF showed the presence of the 1.5 T TMF can slightly reduce V100% and D95% for PTV, with the differences being less than 4% for all but one lung case studied. The TMF results in considerable increases in Dmax and D1cc on the skin in all cases, mostly between 10% and 35%. The changes in Dmax and D1cc on air cavity walls are dependent upon site, geometry, and size, with changes ranging up to 15%. The VMAT plans lead to much smaller dose effects from ERE compared to fixed-beam IMRT in pancreas case. When the TMF is considered in the plan optimization, the dose effects of the TMF at tissue interfaces (e.g., air-cavity wall, lung-tissue interfaces, skin) are

  7. 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.

  8. Shuttle/typical payload interface study

    NASA Technical Reports Server (NTRS)

    Mansfield, J. M.

    1972-01-01

    Concept synthesis and preliminary design studies are summarized of support systems to implement the launch/refurbishment/retrieval with shuttle of a family of low cost earth observation satellites in low earth orbit. Shuttle constraints and issues are described.

  9. a Study of Some Metal-Semiconductor Interfaces.

    NASA Astrophysics Data System (ADS)

    Maani, Colette

    Available from UMI in association with The British Library. The aim of this study was to investigate a number of specific metal-semiconductor interfaces with the goal of understanding the mechanism responsible for Schottky barrier formation at these interfaces. Metal contacts of group III, gallium, and group V, antimony were evaporated onto the clean cleaved indium phosphide(110) surface. Techniques of low energy electron defraction, Auger electron spectroscopy, ultra violet and X-ray photoelectric spectroscopy, current-voltage and capacitance -voltage measurements were used to probe the structural, chemical and electronic nature of the metal-semiconductor interfaces formed. In addition metal contacts of Al, Ag, Au and Sn were evaporated onto the clean cleaved gallium phosphide(110) surface. Techniques of current-voltage, capacitance-voltage and photoresponse measurements were used in order to determine barrier height. The study of Ga and Sb on InP(110) was used to investigate the importance of chemical reactivity, growth mode, defect formation and interdiffusion at the interface. The investigation of a range of metals on GaP(110) was an attempt to understand metal-semiconductor Schottky barrier formation in terms of this wide band gap material. Both studies were used to test the relevance of various proposed models of Schottky barrier formation at metal-semiconductor interfaces. (Abstract shortened by UMI.).

  10. 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.

  11. 29 CFR 1607.14 - Technical standards for validity studies.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... validity studies. Users choosing to validate a selection procedure by a content validity strategy should... by this strategy should therefore take particular care to assure that the validity study meets the... 29 Labor 4 2014-07-01 2014-07-01 false Technical standards for validity studies. 1607.14 Section...

  12. 29 CFR 1607.14 - Technical standards for validity studies.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... validity studies. Users choosing to validate a selection procedure by a content validity strategy should... by this strategy should therefore take particular care to assure that the validity study meets the... 29 Labor 4 2010-07-01 2010-07-01 false Technical standards for validity studies. 1607.14 Section...

  13. 29 CFR 1607.14 - Technical standards for validity studies.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... validity studies. Users choosing to validate a selection procedure by a content validity strategy should... by this strategy should therefore take particular care to assure that the validity study meets the... 29 Labor 4 2011-07-01 2011-07-01 false Technical standards for validity studies. 1607.14 Section...

  14. 29 CFR 1607.14 - Technical standards for validity studies.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... validity studies. Users choosing to validate a selection procedure by a content validity strategy should... by this strategy should therefore take particular care to assure that the validity study meets the... 29 Labor 4 2012-07-01 2012-07-01 false Technical standards for validity studies. 1607.14 Section...

  15. Ab-initio study of metal-zirconia interfaces

    NASA Astrophysics Data System (ADS)

    Kulkova, S.; Bakulin, A.; Hocker, S.; Schmauder, S.

    2012-08-01

    A comparative theoretical study of metal-zirconia interfaces with BCC and FCC metals was performed using pseudopotential approach with LDA and GGA approximation for exchange-correlation functional. It was shown that the high adhesion can be achieved at the O-terminated Me/ZrO2(001) interface with BCC metals that is related to large charge transfer from metal film to substrate and increase of an ionic contribution in the chemical bonding. The structural and electronic factors which are responsible for decrease of adhesion at differently oriented metal-zirconia interfaces are discussed. The influence of CaO, MgO and Y2O3 doping on the work of separation (Wsep) at Me(001)/c-ZrO2(001) is analyzed.

  16. Technical considerations in radionuclide gastric emptying studies

    SciTech Connect

    Christian, P.E.; Datz, F.L.; Moore, J.G.

    1987-12-01

    This is the final article in a four-part Continuing Education series on quantitative imaging techniques. After studying this article, the reader should be able to: 1) identify proper use of radiopharmaceuticals and meal composition for gastric emptying studies; 2) discuss appropriate imaging techniques; and 3) discuss methods of data analysis.

  17. Technical Writing Redesign and Assessment: A Pilot Study

    ERIC Educational Resources Information Center

    Winter, Gaye Bush

    2010-01-01

    The purpose of this study was to compare scores on writing assignments from traditional, fully online courses in technical writing to pilot, hybrid courses at a southern university. A total of 232 students' assignments were compared in this study. All writing assignments were scored by six trained instructors of English using the same five point…

  18. Studies of Silicon-Refractory Metal Interfaces: Photoemission Study of Interface Formation and Compound Nucleation.

    DTIC Science & Technology

    1984-10-29

    Rev. B 28, 7000-7008 (1983). - J.H. Weaver, A. Franciosi, and V.L. Moruzzi, "Bonding in Metal Disilicides CaSi 2 through NiSi2 : Experiment and Theory...information about the elec- impurities and Dow Coming Si (resistivity of 1000 tronic and structural properties of interfaces as they 11 cm). The starting...bulk properties , in- growth. Analysis of the resulting C’Si2 ingot showed cluding stoichiometry, disorder, segregation, and chemical 48.02 wt

  19. 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…

  20. 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…

  1. EUDISED Technical Studies 1973-1974.

    ERIC Educational Resources Information Center

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

    Part of a larger effort in creating a computer-based European Documentation and Information System for Education (EUDISED), the present document contains four papers proposing specifications for procedures and formats to be incorporated in the documentation standards of EUSIDED. The first is a "Preliminary Study for the Design of a Coding…

  2. 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.

  3. 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.

  4. GMT azimuth bogie wheel-rail interface wear study

    NASA Astrophysics Data System (ADS)

    Teran, Jose; Lindh, Cory; Morgan, Chris; Manuel, Eric; Bigelow, Bruce C.; Burgett, William S.

    2016-07-01

    Performance of the GMT azimuth drive system is vital for the operation of the telescope and, as such, all components subject to wear at the drive interface merit a high level of scrutiny for achieving a proper balance between capital costs, maintenance costs, and the risk for downtime during planned and unplanned maintenance or replacement procedures. Of particular importance is the interface between the azimuth wheels and rail, as usage frequency is high, the full weight of the enclosure must be transferred through small patches of contact, and replacement of the rail would pose a greater logistical challenge than the replacement of smaller components such as bearings and gearmotors. This study investigates tradeoffs between various wheel-rail and roller-track interfaces, including performance, complexity, and anticipated wear considerations. First, a survey of railway and overhead crane industry literature is performed and general detailing recommendations are made to minimize wear and the risk of rolling contact fatigue. Second, Adams/VI-Rail is used to simulate lifetime wear of four specific configurations under consideration for the GMT azimuth wheel-rail interface; all studied configurations are shown to be viable, and their relative merits are discussed.

  5. 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.

  6. 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.

  7. Technical procedures for implementation of acoustics site studies, Deaf Smith County site, Texas: Environmental Field Program: Preliminary draft

    SciTech Connect

    Not Available

    1987-09-01

    The purpose and scope of the technical procedure for processing data from the tethered meteorological system are covered. Definitions, interfaces, and concurrent data needs are also addressed. This technical procedure describes how to control, organize, verify, and archive tethered meteorological system data. These data will be received at the processing location from the field measurement location and are part of the characterization of the Deaf Smith County Site, Texas for the salt repository program. These measurements will be made in support of the sound propagation study and are a result of environmental data requirements for acoustics. 6 refs., 15 figs., 5 tabs.

  8. 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…

  9. External wave launcher study. Final technical report

    SciTech Connect

    Moses, K.G.

    1986-06-26

    The overall purpose of this study is to explore the applicability of dielectric filled waveguide launchers to couple ion cyclotron resonant frequency (ICRF) power to magnetically confined plasma. The major advantage of dielectric filled launchers is that the geometrical dimensions of a waveguide launcher required to accommodate an electromagnetic wave of any given frequency can be reduced by the square root of the relative permittivity of the dielectric compared to air or vacuum waveguide dimensions. However, removal of the intense heat load deposited by 14 MeV neutrons in a solid dielectric filled waveguide heating system in close proximity to a fusion reactor presents several major problems: Heat is distributed throughout the volume of solid dielectric by energetic neutrons, which necessitates that a substantial fraction of the dielectric filled waveguide must be occupied by channels containing liquid coolant to remove the heat. The uniformity of the internal dielectric media of the waveguide is disrupted, and electromagnetic waves in the guide will be reflected and scattered at the discontinuities. It is highly questionable that a waveguide or waveguide launcher constructed in this manner will be an efficient means of transmitting ICRF power. This circumstance leads to employing liquid dielectrics which could satisfy both electromagnetic and coolant requirements of ICRF auxiliary launching systems simultaneously. Additionally, liquid dielectrics facilitate the motion of tuning structures through the media and preserve its dielectric uniformity in contrast to the tuning restrictions imposed by solid dielectrics in this regard.

  10. Process monitoring interface for studying the metamorphism in a design

    SciTech Connect

    Bayrak, C.

    1996-12-31

    The efforts to improve the system design methodology, which provides the designer with the ability to exercise the prototype at a high abstraction level and to delay the implementation level activity as far into the development activity as possible, have led us to study the process monitoring issue. Particularly we are interested in the three fundamental issues in process monitoring: the abstract sphere of the design, the practical sphere of the user interface, and the gap between these two spheres. Therefore, an integrated graphical user interface architecture, called Process Monitoring Interface (PMI), is introduced not only for the gap between the abstract spheres and practical affairs of building appropriate user-integrated interface but also for supervising the hierarchical human design notion of the abstract design exercised with more efficiency at the highest possible levels of the development. In using PMI, the user/developer can monitor evolution of highly abstract building blocks that are created at the very beginning of the design process and later be refined into different levels of the design, representing different levels of abstractions of a system.

  11. 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

  12. 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…

  13. 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.

  14. 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…

  15. Technical Guide for Implementing Content Standards: Social Studies, June 1999.

    ERIC Educational Resources Information Center

    South Dakota State Dept. of Education and Cultural Affairs, Pierre.

    This technical guide is a resource to help educators implement the adopted social studies standards for South Dakota. The guide to the standards includes the goals, indicators, benchmarks, and grade level standards. It is organized in grade level clusters according to benchmark levels: K-2, 3-5, 6-8, and 9-12. This format is provided as a…

  16. Workplace Skills in Practice. Case Studies of Technical Work.

    ERIC Educational Resources Information Center

    Stasz, Cathleen; And Others

    A study was conducted to explore skills and work-related dispositions in technical work. It used a sociocultural approach to examine skills in seven target jobs in worksites representing diverse industries--health care, traffic management, transportation, and semiconductor manufacturing. It explored employers' strategies for obtaining the skills…

  17. 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…

  18. 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…

  19. 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…

  20. Quantitative model studies for interfaces in organic electronic devices

    NASA Astrophysics Data System (ADS)

    Gottfried, J. Michael

    2016-11-01

    In organic light-emitting diodes and similar devices, organic semiconductors are typically contacted by metal electrodes. Because the resulting metal/organic interfaces have a large impact on the performance of these devices, their quantitative understanding is indispensable for the further rational development of organic electronics. A study by Kröger et al (2016 New J. Phys. 18 113022) of an important single-crystal based model interface provides detailed insight into its geometric and electronic structure and delivers valuable benchmark data for computational studies. In view of the differences between typical surface-science model systems and real devices, a ‘materials gap’ is identified that needs to be addressed by future research to make the knowledge obtained from fundamental studies even more beneficial for real-world applications.

  1. 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…

  2. 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.

  3. Study of a liquid bridge subjected to interface shear stresses

    NASA Astrophysics Data System (ADS)

    Gaponenko, Yu.; Glockner, S.; Mialdun, A.; Shevtsova, V.

    2011-08-01

    We report on numerical and experimental study of two-phase flows in a tall annulus. The geometry corresponds to a cylindrical liquid column co-axially placed into an outer cylinder with solid walls. The internal column consists of solid supports at the bottom and top, while the central part is a liquid zone filled with viscous liquid and kept in its position by surface tension. Gas enters into the annular duct and entrains initially quiescent liquid. The liquid bridge interface is deformed by gravity and by a co-axial gas flow which is co- and counter directed with respect to gravity. A new experimental set-up including an optical system for precise measurements of the interface displacement has been designed and developed. In the experiments silicone oil 5cSt was used as a test liquid and air as gas. On numerical side the dynamical response of an isothermal liquid bridge to a coaxial gas flow is examined by simulations of the Navier-Stokes equations. The attention is focused on the following points: time-dependent formation of the equilibrium shape of a liquid bridge in gravity conditions and its deformation by a gas flow, simulation of a flow pattern in a liquid/gas system with deformed free surface. The comparison of the numerical and experimental results for the interface deformation exhibits a satisfactory agreement.

  4. Market Assessment and Technical Feasibility Study of PFBC Ash Use

    SciTech Connect

    Bland, A.E.; Brown, T.H.; Georgiou, D.N.

    1995-03-01

    The commercial introduction of pressurized fluidized bed combustion (PFBC) has spurred evaluation of ash management options for this technology. The unique operating characteristics of PFBC compared to atmospheric fluidized bed combustion (AFBC) units indicate that PFBC ash will exhibit unique chemical and physical characteristics, and hence, unique ash use opportunities. Western Research Institute (WRI), under sponsorship of the Electric Power Research Institute (EPRI), Ahlstrom Pyropower, Inc., and the U.S. Department of Energy (DOE) Morgantown Energy Technology Center (METC), has initiated a study of the use properties of PFBC ashes involving both an assessment of the potential markets, as well as a technical feasibility study of specific use options. The market assessment is designed to address six applications, including: (1) structural fill, (2) road base construction, (3) supplementary cementing materials in portland cement, (4) bricks and blocks, (5) synthetic aggregate, and (6) agricultural/soil amendment applications. Ashes from the Ahlstrom circulating PFBC pilot facility in Caroler, Finland, combusting western U.S. low-sulfur subbituminous coal with limestone sorbent, were made available for the technical feasibility study. The technical feasibility study examined the use of PFBC ash in construction-related applications, including its use as a supplemental cementing material in concrete, fills and embankments, soil stabilization, and synthetic aggregate production. In addition, testing was conducted to determine the technical feasibility of PFBC ash as a soil amendment for agricultural and reclamation applications. PFBC ash does not meet the ASTM 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 set retardant. PFBC ash shows relatively high strength development, low expansion and low permeability properties that make its use in fills and

  5. Technical Feasibility Study for Zero Energy K-12 Schools

    SciTech Connect

    Bonnema, Eric; Goldwasser, David; Torcellini, Paul; Pless, Shanti; Studer, Daniel

    2016-11-01

    This technical feasibility study provides documentation and research results supporting a possible set of strategies to achieve source zero energy K-12 school buildings as defined by the U.S. Department of Energy (DOE) zero energy building (ZEB) definition (DOE 2015a). Under this definition, a ZEB is an energy-efficient building in which, on a source energy basis, the actual annual delivered energy is less than or equal to the on-site renewable exported energy.

  6. C-V and DLTS studies of radiation induced Si-SiO2 interface defects

    NASA Astrophysics Data System (ADS)

    Capan, I.; Janicki, V.; Jacimovic, R.; Pivac, B.

    2012-07-01

    Interface traps at the Si-SiO2 interface have been and will be an important performance limit in many (future) semiconductor devices. In this paper, we present a study of fast neutron radiation induced changes in the density of Si-SiO2 interface-related defects. Interface related defects (Pb centers) are detected before and upon the irradiation. The density of interface-related defects is increasing with the fast neutron fluence.

  7. First principles modeling of the metal-electrolyte interface: A novel approach to the study of the electrochemical interface

    SciTech Connect

    Fernandez-Serra, Maria Victoria

    2016-09-12

    The research objective of this proposal is the computational modeling of the metal-electrolyte interface purely from first principles. The accurate calculation of the electrostatic potential at electrically biased metal-electrolyte interfaces is a current challenge for periodic “ab-initio” simulations. It is also an essential requisite for predicting the correspondence between the macroscopic voltage and the microscopic interfacial charge distribution in electrochemical fuel cells. This interfacial charge distribution is the result of the chemical bonding between solute and metal atoms, and therefore cannot be accurately calculated with the use of semi-empirical classical force fields. The project aims to study in detail the structure and dynamics of aqueous electrolytes at metallic interfaces taking into account the effect of the electrode potential. Another side of the project is to produce an accurate method to simulate the water/metal interface. While both experimental and theoretical surface scientists have made a lot of progress on the understanding and characterization of both atomistic structures and reactions at the solid/vacuum interface, the theoretical description of electrochemical interfaces is still lacking behind. A reason for this is that a complete and accurate first principles description of both the liquid and the metal interfaces is still computationally too expensive and complex, since their characteristics are governed by the explicit atomic and electronic structure built at the interface as a response to environmental conditions. This project will characterize in detail how different theoretical levels of modeling describer the metal/water interface. In particular the role of van der Waals interactions will be carefully analyzed and prescriptions to perform accurate simulations will be produced.

  8. Technical Feasibility Study for Zero Energy K-12 Schools

    SciTech Connect

    Pless, Shanti D.; Torcellini, Paul A.; Bonnema, Eric; Goldwasser, David

    2016-08-26

    A simulation-based technical feasibility study was completed to show the types of technologies required to achieve ZEB status with this building type. These technologies are prioritized across the building's subsystem such that design teams can readily integrate the ideas. Energy use intensity (EUI) targets were established for U.S. climate zones such that K-12 schools can be zero-ready or can procure solar panels or other renewable energy production sources to meet the zero energy building definition. Results showed that it is possible for K-12 schools to achieve zero energy when the EUI is between 20 and 26 kBtu/ft2/yr. Temperate climates required a smaller percentage of solar panel coverage than very hot or very cold climates. The paper provides a foundation for technically achieving zero energy schools with a vision of transforming the school construction market to mainstream zero energy buildings within typical construction budgets.

  9. 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).

  10. Hydrogen release at metal-oxide interfaces: A first principle study of hydrogenated Al/SiO2 interfaces

    NASA Astrophysics Data System (ADS)

    Huang, Jianqiu; Tea, Eric; Li, Guanchen; Hin, Celine

    2017-06-01

    The Anode Hydrogen Release (AHR) mechanism at interfaces is responsible for the generation of defects, that traps charge carriers and can induce dielectric breakdown in Metal-Oxide-Semiconductor Field Effect Transistors. The AHR has been extensively studied at Si/SiO2 interfaces but its characteristics at metal-silica interfaces remain unclear. In this study, we performed Density Functional Theory (DFT) calculations to study the hydrogen release mechanism at the typical Al/SiO2 metal-oxide interface. We found that interstitial hydrogen atoms can break interfacial Alsbnd Si bonds, passivating a Si sp3 orbital. Interstitial hydrogen atoms can also break interfacial Alsbnd O bonds, or be adsorbed at the interface on aluminum, forming stable Alsbnd Hsbnd Al bridges. We showed that hydrogenated Osbnd H, Sisbnd H and Alsbnd H bonds at the Al/SiO2 interfaces are polarized. The resulting bond dipole weakens the Osbnd H and Sisbnd H bonds, but strengthens the Alsbnd H bond under the application of a positive bias at the metal gate. Our calculations indicate that Alsbnd H bonds and Osbnd H bonds are more important than Sisbnd H bonds for the hydrogen release process.

  11. The MedlinePlus public user interface: studies of design challenges and opportunities

    PubMed Central

    Marill, Jennifer L.; Miller, Naomi; Kitendaugh, Paula

    2006-01-01

    Question: What are the challenges involved in designing, modifying, and improving a major health information portal that serves over sixty million page views a month? Setting: MedlinePlus, the National Library of Medicine's (NLM's) consumer health Website, is examined. Method: Challenges are presented as six “studies,” which describe selected design issues and how NLM staff resolved them. Main Result: Improving MedlinePlus is an iterative process. Changes in the public user interface are ongoing, reflecting Web design trends, usability testing recommendations, user survey results, new technical requirements, and the need to grow the site in an orderly way. Conclusion: Testing and analysis should accompany Website design modifications. New technologies may enhance a site but also introduce problems. Further modifications to MedlinePlus will be informed by the experiences described here. PMID:16404467

  12. High temperature microelectrophoresis studies of the solid oxide/water interface

    NASA Astrophysics Data System (ADS)

    Fedkin, Mark Valentinovich

    Metal oxides are abundant components of geo-environmental systems and are widely used materials in industry. Many practical applications of oxide materials require the knowledge of their surface properties at both ambient and elevated temperatures. Due to substantial technical challenges associated with experimental studies of solid/water interfaces at elevated temperatures, consistent data on adsorption, surface charge, and zeta potential for most oxide materials are limited to temperatures less than 100°C. A high temperature microelectrophoresis technique, developed in this study, made it possible to extend the zeta potential measurements at the solid oxide/water interface to 200°C. The design of the high temperature electrophoresis cell allowed for the visual microscopic observation of the electrophoretic movement of suspended particles through pressure-tight sapphire windows. The electrophoretic mobilities of metal oxide particles suspended in aqueous solutions were measured in a DC electric field as a function of pH, ionic strength, and temperature. The experimental procedure and methods for evaluation of the main experimental parameters (electrophoretic mobility, electric field strength, high temperature pH, and cell constant) have been developed. Zeta potentials were calculated from the experimental data using O'Brien and White's (1978) numerical solution for electrophoretic mobility equation. Zeta potentials and isoelectric points (IEP) of the metal oxide/aqueous solution interface were experimentally determined for ZrO2, TiO 2(rutile), and alphaAl2O3 at 25, 120, and 200°C. The background solutions used for the preparation of suspensions were pure H2O, NaCl(aq) (10-4--10-2 mol.kg-1), and SrCl2 (10-4 mol.kg, for TiO2). For all studied materials, the IEPs were found to regularly decrease with increasing temperature, which agrees with available theoretical predictions. Thermodynamic functions, including Gibbs energy, enthalpy, and heat capacity, were

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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…

  19. 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…

  20. 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.

  1. Study of large flexible tunnel for shuttle/payload interface

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A theoretical and preliminary design study of a large flexible tunnel for use at the shuttle/payload interface is discussed. The theoretical study consisted of evaluating various design concepts and determining their adaptability to the tunnel requirements. The theoretical study culminated in the selection of one concept. The selected concept was documented with preliminary drawings of a full-scale ground test model. Supporting preliminary structural, thermal, micrometeoroid, material, and weight analyses were conducted. The specified tunnel requirements could be broadly grouped into two categories; environmental and performance. The environmental requirements were those ambient conditions and loads associated with ground, launch, space and reentry of the shuttle vehicle. Materials are presently available which will meet all these environmental requirements and can be designed into the structure to withstand the specified loads.

  2. 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.

  3. 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

  4. Mental practice enhances surgical technical skills: a randomized controlled study.

    PubMed

    Arora, Sonal; Aggarwal, Rajesh; Sirimanna, Pramudith; Moran, Aidan; Grantcharov, Teodor; Kneebone, Roger; Sevdalis, Nick; Darzi, Ara

    2011-02-01

    To assess the effects of mental practice on surgical performance. Increasing concerns for patient safety have highlighted a need for alternative training strategies outside the operating room. Mental practice (MP), "the cognitive rehearsal of a task before performance," has been successful in sport and music to enhance skill. This study investigates whether MP enhances performance in laparoscopic surgery. After baseline skills testing, 20 novice surgeons underwent training on an evidence-based virtual reality curriculum. After randomization using the closed envelope technique, all participants performed 5 Virtual Reality (VR) laparoscopic cholecystectomies (LC). Mental practice participants performed 30 minutes of MP before each LC; control participants viewed an online lecture. Technical performance was assessed using video Objective Structured Assessment of Technical Skills-based global ratings scale (scored from 7 to 35). Mental imagery was assessed using a previously validated Mental Imagery Questionnaire. Eighteen participants completed the study. There were no intergroup differences in baseline technical ability. Learning curves were demonstrated for both MP and control groups. Mental practice was superior to control (global ratings) for the first LC (median 20 vs 15, P = 0.005), second LC (20.5 vs 13.5, P = 0.001), third LC (24 vs 15.5, P < 0.001), fourth LC (25.5 vs 15.5, P < 0.001) and the fifth LC (27.5 vs 19.5, P = 0.00). The imagery for the MP group was also significantly superior to the control group across all sessions (P < 0.05). Improved imagery significantly correlated with better quality of performance (ρ 0.51–0.62, Ps < 0.05). This is the first randomized controlled study to show that MP enhances the quality of performance based on VR laparoscopic cholecystectomy. This may be a time- and cost-effective strategy to augment traditional training in the OR thus potentially improving patient care.

  5. Technical Reliability Studies. EOS/ESD Technology Abstracts

    DTIC Science & Technology

    1982-01-01

    FOR VOLTAGE TRANSIENT SUPPRESSORS (120 V, AC TYPE) 15773 TRANSIENT PROTECTION WITH ZNO VARISTORS : TECHNICAL CONSIDERATIONS 15469 KEY SUPPRESSION...SEMICONDUCTOR DEVICES 15773 TRANSIENT PROTECTION WITH ZNO VARISTORS : TECHNICAL CONSIDERATIONS 15725 ELECTRICAL OVERSTRESS FAILURE ANALYSIS IN HICROCIRCUITS...PROTECTION WITH ZNO VARISTORS : TECHNICAL CONSIDERATIONS 15469 KEY SUPPRESSION DEVICE PARAMETERS FOR EMP HARDENING 15204 EFFECT OF LEAD WIRE LENGTHS ON

  6. 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.

  7. Space station resistojet system requirements and interface definition study

    NASA Technical Reports Server (NTRS)

    Finden, L. E.

    1987-01-01

    A conceptual design study of the resistojet orbital replacement unit (ORU) was conducted. The ORU consists of four 500-W multipropellant resistojets, fluid components downstream of the waste fluid storage subsystem, a power controller, structure, and micrometeorite shielding. The fluid components include latch valves, a water vaporizer, two pressure regulators or flow control valves, filters, check valves, fluid tubing, and interface couplings. Separate fluid components are provided for oxidizing fluids, reducing fluids and water. Different flow and power control methods were studied. The most promising methods consist of a constant pressure/on-off power control and a constant power/variable pressure control. The closed-loop power control incorporates a feedback signal which is proportional to resistojet heater temperature.

  8. 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.

  9. Space Shuttle flight crew/computer interface simulation studies.

    NASA Technical Reports Server (NTRS)

    Callihan, J. C.; Rybarczyk, D. T.

    1972-01-01

    An approach to achieving an optimized set of crew/computer interface requirements on the Space Shuttle program is described. It consists of defining the mission phases and crew timelines, developing a functional description of the crew/computer interface displays and controls software, conducting real-time simulations using pilot evaluation of the interface displays and controls, and developing a set of crew/computer functional requirements specifications. The simulator is a two-man crew station which includes three CRTs with keyboards for simulating the crew/computer interface. The programs simulate the mission phases and the flight hardware, including the flight computer and CRT displays.

  10. 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,…

  11. 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,…

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

    SciTech Connect

    Mullin, Christopher Shane

    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.

  13. Technical-economic studies of geothermal projects: the Djibouti case

    SciTech Connect

    Abdallah, A.; Gandino, A.; Sommaruga, C.

    1985-01-01

    Geothermal exploitation projects require very high initial investments and a relatively long recovery time. Before financing a project, a study must be made to determine its feasibility from technical and economic point of view. A study of this type performed in the Republic of Djibouti has demonstrated that a geothermal project for power production offers numerous economic advantages. Estimates have been made of the production cost of conventional power (diesel oil) and of geothermal power, based on the results o recent geothermal exploration in this country and on the current economic situation. Production costs hav been compared and an analysis performed on the economic feasibility of a geothermal program, including deep well drilling, installation of a 20 MW power plant and transmission line for production in Djibouti City of 130 GWh/year over a 25 year period. An evaluation has also been made of the prospects for integrated geothermal development (agriculture, stock breeding, mineral resources and hydrothermalism).

  14. 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.

  15. 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.

  16. 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…

  17. 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…

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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)…

  3. System Engineering Concept Demonstration, Interface Standards Studies. Volume 4

    DTIC Science & Technology

    1992-12-01

    standard operations, such as copy, delete , move, and store, and policies of the Common Programming Interface (CPI). As a central focus of the AD/Cycle...l to the tool. A number of system tools, such as mail, dir, copy, delete , conform to the SLCSE interface. A tool writer has the option of developing...elements can be accessed and deleted . Structure modifications are performed through structure editing. These operations are independent of the type of

  4. Analytical Transmission Electron Microscopy Studies on Copper-Alumina Interfaces.

    DTIC Science & Technology

    1999-06-01

    examine the data carefully in order to assess the interdependence, if any, between each aspect in relation to the interface microstructure. Finally, there...Eo = accelerating voltage (kV) Z = atomic number A = atomic weight t = thickness (cm) p = density (g cmŗ). b is related to d;, the initial beam...th ng, Proc. 4 Japan International SAMPE Trumble, K. P., Themodynamic Analysis of Aluminate formation at Fe/AhO^ and C14/AI2O3 Interfaces, Acta

  5. 75 FR 359 - Guidance on Simultaneous Transmission Import Limit Studies; Notice Allowing Post-Technical...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-05

    ... on Simultaneous Transmission Import Limit Studies; Notice Allowing Post-Technical Conference Comments... Simultaneous Transmission Import Limit (SIL) studies. All interested persons are invited to file written...

  6. Brain-computer interfacing under distraction: an evaluation study

    NASA Astrophysics Data System (ADS)

    Brandl, Stephanie; Frølich, Laura; Höhne, Johannes; Müller, Klaus-Robert; Samek, Wojciech

    2016-10-01

    Objective. While motor-imagery based brain-computer interfaces (BCIs) have been studied over many years by now, most of these studies have taken place in controlled lab settings. Bringing BCI technology into everyday life is still one of the main challenges in this field of research. Approach. This paper systematically investigates BCI performance under 6 types of distractions that mimic out-of-lab environments. Main results. We report results of 16 participants and show that the performance of the standard common spatial patterns (CSP) + regularized linear discriminant analysis classification pipeline drops significantly in this ‘simulated’ out-of-lab setting. We then investigate three methods for improving the performance: (1) artifact removal, (2) ensemble classification, and (3) a 2-step classification approach. While artifact removal does not enhance the BCI performance significantly, both ensemble classification and the 2-step classification combined with CSP significantly improve the performance compared to the standard procedure. Significance. Systematically analyzing out-of-lab scenarios is crucial when bringing BCI into everyday life. Algorithms must be adapted to overcome nonstationary environments in order to tackle real-world challenges.

  7. Flight 1 technical report for experiment 74-36: Thermal migration of bubbles and their interaction with solidification interfaces

    NASA Technical Reports Server (NTRS)

    Papazian, J. M.; Wilcox, W. R.

    1976-01-01

    Specimens of gas saturated carbon tetrabromide were directionally solidified in a transparent furnace using a gradient freeze technique. The original temperature gradient was 5 C/cm and the cooling rate was 40 C/h. Progress of the experiment was monitored photographically. Gas bubbles were generated at the advancing solidification front in each of the three specimens. The gas bubbles were observed to increase in size, coalesce, and eventually be grown into the solid specimen under low gravity conditions. No bubble detachment from the interface was observed. Identical specimens processed in the laboratory showed bubble nucleation, bubble growth, and eventual bubble detachment due to buoyancy forces. Examination of the specimens showed a significantly greater void content in the low gravity processed samples. The grain size was observed to be finer in the low gravity processed samples.

  8. 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

  9. Studies of the magnetic structure at the ferromagnet - antiferromagnet interface

    SciTech Connect

    Scholl, A.; Nolting, F.; Stohr, J.; Luning, J.; Seo, J.W.; Locquet, J.-P.; Anders, S.; Ohldag, H.; Padmore, H.A.

    2001-01-02

    Antiferromagnetic layers are a scientifically challenging component in magneto-electronic devices such as magnetic sensors in hard disk heads, or magnetic RAM elements. In this paper we show that photo-electron emission microscopy (PEEM) is capable of determining the magnetic structure at the interface of ferromagnets and antiferromagnets with high spatial resolution (down to 20 nm). Dichroism effects at the L edges of the magnetic 3d transition metals, using circularly or linearly polarized soft x-rays from a synchrotron source, give rise to a magnetic image contrast. Images, acquired with the PEEM2 experiment at the Advanced Light Source, show magnetic contrast for antiferromagnetic LaFeO{sub 3}, microscopically resolving the magnetic domain structure in an antiferromagnetically ordered thin film for the first time. Magnetic coupling between LaFeO{sub 3} and an adjacent Co layer results in a complete correlation of their magnetic domain structures. From field dependent measurements a unidirectional anisotropy resulting in a local exchange bias of up to 30 Oe in single domains could be deduced. The elemental specificity and the quantitative magnetic sensitivity render PEEM a perfect tool to study magnetic coupling effects in multi-layered thin film samples.

  10. 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).

  11. Basic research in nuclear test monitoring: Seismic wave scattering from irregular interfaces. Final technical report, 1 August 1992-31 July 1994

    SciTech Connect

    Schultz, C.A.; Dainty, A.M.; Toksoez, M.N.

    1994-12-16

    We report on two investigations of seismic wave scattering from irregular interfaces. The first is a laboratory study of the scattering of ultrasonic waves incident on a glass surface etched to produce a highly irregular 3-D interface. We find that 2-D numerical simulations predict the 3-D experimental results well at small incident angles. Both numerical and experimental results strongly support the presence of enhanced backscattering. The second study is an analysis of regional P wave coda observed from events recorded at the Scandinavian NORESS, FINESA, and ARCESS arrays and the New England NYNEX array. The F-K spectra of the P coda are dominated by on-azimuth energy with apparent velocities between Pn (or faster) and Lg. Following this analysis, reflection coefficients calculated with a boundary integral scheme are used to study the role irregular interfaces play in the creation of regional P coda. We find that observed crustal scattering in these regions is strikingly consistent with P-P and P-SV scattering from the 2-D irregular Moho and even more consistent with scattering from a 2-D irregular near surface interface.

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

    SciTech Connect

    Roberts, B.B.; Bland, D.

    1988-12-01

    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.

  13. 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.

  14. 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.

  15. Atomic and electronic structure of polar oxide interfaces: Electron microscopy and density functional theory study

    NASA Astrophysics Data System (ADS)

    Lazarov, Vlado

    Polar oxide interfaces are formed when two polar oxide surfaces join. The apparent presence of an electric dipole moment in the repeat unit parallel to the surface/interface closely relate the polar oxide interfaces instability to that of the of polar oxide surfaces. In this thesis, we combined Electron Microscopy and Density Functional Theory to study how the interface polarity affects the atomic and electronic structure of polar oxide interfaces, by using Fe3O4(111)/MgO(111) as a model system. The formation of Fe nanoinclusions found at the interface and within the polar Fe3 O4(111) film is proposed to be new stabilization mechanism for the magnetite film. High-resolution electron microscopy imaging of the interface together with first principle calculations suggest an atomically abrupt substrate-film interface determined with Fe monolayer in octahedral position (FeB). This interface stacking (O/Mg/O/3FeB/O) provides lowest total interface (system) energy and the most effectively screening of the MgO(111) substrate surface polarity. The results of our study suggest that surface polarity could be used as an additional growth parameter in creating novel material structures, such as metals in oxide matrices.

  16. The Work-Study Interface: Similarities and Differences between Ethnic Minority and Ethnic Majority Students

    ERIC Educational Resources Information Center

    Meeuwisse, Marieke; de Meijer, Lonneke A.; Born, Marise Ph.; Severiens, Sabine E.

    2017-01-01

    Given the poorer academic outcomes of non-Western ethnic minority students compared to ethnic majority students, we investigated whether differences exist in work-study interface between ethnic groups. We tested a work-study interface model, in which the work-related factors work-study congruence, job control, job demands, work hours, job…

  17. XPS study of the hematite-aqueous solution interface

    SciTech Connect

    Shchukarev, Andrei; Boily, Jean F.

    2008-04-01

    The electric double layer at the surface of micrometer-sized hematite platelets dominated by the basal {001} and the edge {012} planes was investigated using the cryogenic XPS technique. Thoroughly dialysed hematite suspensions revealed the presence of surface-bound sodium (2.2 at. %) and chloride (0.4 at. %). Suspensions in 10 mM and 100 mM NaCl revealed additional uptake of sodium and chloride. The Na/Cl atomic ratio follows the pH dependence found with previous studies of goethite, manganite and gibbsite. An excess of Cl- was demonstrated at positively charged hematite surface, and Na+ at negatively charged surfaces. The surface coverage of electrolyte ions was also shown to play an important role on the presence of water at the interface. At low ionic strength the water content was about of 10 at. %, yielding a water/counter-ions atomic ratio of about 3-6, depending on pH. At 100 mM NaCl, however, the large atomic concentrations of sodium and chloride resulted in a water content of about 25 at. %, nonetheless yielding a water/counter-ion atomic ratio about 1. The presence of 100 mM CsCl, on the other hand, yielded the same amount of surface-bound water as in 10 mM NaCl due to a lower surface coverage for Cs and to its weaker affinity for water. Finally, a non-equilibrated hematite sample at pH 4 enabled a description the formation of the electric double layer upon addition of 100 mM NaCl to an electrolyte-free suspension

  18. 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.

  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. Ellipsometric study of depletion at oil-water interfaces.

    PubMed

    Day, James P R; Bain, Colin D

    2007-10-01

    Ellipsometry is exquisitely sensitive to density variations across a fluid-fluid interface. The coefficient of ellipticity at the interface between water and a series of nonpolar and polar oils is the opposite sign to that predicted for an interface roughened by thermal capillary waves. For pure hydrocarbons, the coefficient of ellipticity is correlated with the refractive index of the oil, but is largely independent of the molecular architecture of the oil phase, ruling out molecular alignment at the interface as the major cause of the deviation from the capillary-wave model. The introduction of a "drying" layer between the oil and water can explain the experimental data. The thickness of the drying layer, modeled as a slab with a relative permittivity of unity, was only 0.3-0.4 A, which is close to that expected simply from the hard sphere repulsion of a hydrocarbon surface. For polar oils, the coefficient of ellipticity decreases as the interfacial tension decreases, consistent with the reduction in thickness of the hard-sphere exclusion region on account of the formation of hydrogen bonds to water.

  1. Ellipsometric study of depletion at oil-water interfaces

    NASA Astrophysics Data System (ADS)

    Day, James P. R.; Bain, Colin D.

    2007-10-01

    Ellipsometry is exquisitely sensitive to density variations across a fluid-fluid interface. The coefficient of ellipticity at the interface between water and a series of nonpolar and polar oils is the opposite sign to that predicted for an interface roughened by thermal capillary waves. For pure hydrocarbons, the coefficient of ellipticity is correlated with the refractive index of the oil, but is largely independent of the molecular architecture of the oil phase, ruling out molecular alignment at the interface as the major cause of the deviation from the capillary-wave model. The introduction of a “drying” layer between the oil and water can explain the experimental data. The thickness of the drying layer, modeled as a slab with a relative permittivity of unity, was only 0.3-0.4Å , which is close to that expected simply from the hard sphere repulsion of a hydrocarbon surface. For polar oils, the coefficient of ellipticity decreases as the interfacial tension decreases, consistent with the reduction in thickness of the hard-sphere exclusion region on account of the formation of hydrogen bonds to water.

  2. 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.

  3. 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.

  4. An Empirical Study on Operator Interface Design for Handheld Devices to Control Micro Aerial Vehicles

    DTIC Science & Technology

    2010-10-01

    An Empirical Study on Operator Interface Design for Handheld Devices to Control Micro Aerial Vehicles Ming Hou...Report DRDC Toronto TR 2010-075 October 2010 An Empirical Study on Operator Interface Design for Handheld Devices to...drives the need for a small and light controller which will not hinder a soldier carrying it. This requirement brings an issue of designing an

  5. 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.

  6. 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.

  7. 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.

  8. The study about the resistive switching based on graphene/NiO interfaces

    NASA Astrophysics Data System (ADS)

    Dai, Yuehua; Ma, Chengzhi; Zhang, Xu; Wang, Feifei; Lu, Wenjuan; Yang, Jin; Yang, Fei

    2017-08-01

    Six different interfaces namely, armchair Graphene (aGNR), zigzag Graphene (zGNR), and surface defect zigzag Graphene (zGNR1) nanoribbons with uni- and bi-laminar <001>-oriented NiO were studied. First, the Mulliken mean and difference populations, the interface energy, and the interface adhesion energy were calculated by the Cambridge sequential total energy package (CASTEP). The aGNR/NiO interface showed higher interface adhesion energy and Mulliken population mean as compared to the other interface structures (i.e., aGNR/NiO was more compact than the rest of interfaces). Moreover, the lowest interface energy and Mulliken difference population values along with the negligible aberration state clearly revealed aGNR/NiO to be the best interface among those studied herein. Subsequently, the current-voltage (I-V) curves indicate the aGNR/NiO/aGNR device presents memory effect while tracing the path back in the current data, but not switching between positive and negative voltages due to the device unipolar behavior. The mechanism of resistive switching is demonstrated by performing density functional tight binding and much more (DFTB+) dynamics.

  9. 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.

  10. A cylindrical converging shock tube for shock-interface studies.

    PubMed

    Luo, Xisheng; Si, Ting; Yang, Jiming; Zhai, Zhigang

    2014-01-01

    A shock tube facility for generating a cylindrical converging shock wave is developed in this work. Based on the shock dynamics theory, a specific wall profile is designed for the test section of the shock tube to transfer a planar shock into a cylindrical one. The shock front in the converging part obtained from experiment presents a perfect circular shape, which proves the feasibility and reliability of the method. The time variations of the shock strength obtained from numerical simulation, experiment, and theoretical estimation show the desired converging effect in the shock tube test section. Particular emphasis is then placed on the problem of shock-interface interaction induced by cylindrical converging shock waves. For this purpose, membrane-less gas cylinder is adopted to form the interface between two different fluids while the laser sheet technique to visualize the flow field. The result shows that it is convenient to perform such experiments in this facility.

  11. Nanoscale studies of ferroelectric domain walls as pinned elastic interfaces

    NASA Astrophysics Data System (ADS)

    Paruch, Patrycja; Guyonnet, Jill

    2013-10-01

    The competition between elasticity and pinning of an interface in a fluctuating potential energy landscape gives rise to characteristic self-affine roughening and a complex dynamic response to applied forces. This statistical physics approach provides a general framework in which the behaviour of systems as diverse as propagating fractures, wetting lines, burning fronts or surface growth can be described. Domain walls separating regions with different polarisation orientation in ferroelectric materials are another example of pinned elastic interfaces, and can serve as a particularly useful model system. Reciprocally, a better understanding of this fundamental physics allows key parameters controlling domain switching, growth, and stability to be determined, and used to improve the performance of ferroelectric materials in applications such as memories, sensors, and actuators. In this review, we focus on piezoresponse force microscopy measurements of individual ferroelectric domain walls, allowing their static configuration and dynamic response to be accessed with nanoscale resolution over multiple orders of length scale and velocity. Combined with precise control over the applied electric field, temperature, and strain, and the ability to influence the type and density of defects present in the sample, this experimental system has allowed not only a direct demonstration of creep motion and roughening, but provides an opportunity to test less-well-understood aspects of out-of-equilibrium behaviour, and the effects of greater complexity in the structure of both the interface and the disorder landscape pinning it.

  12. Feasibility, Efficacy, and Predictive Factors for the Technical Success of Endoscopic Nasogallbladder Drainage: A Prospective Study

    PubMed Central

    Yane, Kei; Maguchi, Hiroyuki; Katanuma, Akio; Takahashi, Kuniyuki; Osanai, Manabu; Kin, Toshifumi; Takaki, Ryo; Matsumoto, Kazuyuki; Gon, Katsushige; Matsumori, Tomoaki; Tomonari, Akiko; Nojima, Masanori

    2015-01-01

    Background/Aims Several studies have shown the usefulness of endoscopic nasogallbladder drainage (ENGBD) in patients with acute cholecystitis. However, the procedure is difficult, and factors that affect technical success have not yet been clarified. We conducted a prospective study to evaluate the technical feasibility, efficacy, and predictive factors for the technical success of ENGBD in patients with acute cholecystitis. Methods All patients with moderate or severe acute cholecystitis who were enrolled underwent ENGBD between April 2009 and April 2011. Patients with surgically altered anatomy or pancreatobiliary malignancies were excluded. The primary outcomes included technical success, clinical success, and complications. Factors that could affect the technical success were also examined. Results Of the 27 patients who underwent ENGBD during the study period, technical success was achieved in 21 (78%) and clinical improvement was achieved in 20 (95%). Early complications were encountered in four patients (15%). Gallbladder wall thickness (odds ratio [OR], 1.64; 95% confidence interval [CI], 1.08 to 2.47) and age (OR, 1.16; 95% CI, 1.00 to 1.35) were effective predictors of technical failure. Conclusions ENGBD was effective in resolving acute cholecystitis; however, this modality was technically challenging and had a limited success rate. Because of technical difficulties, ENGBD should be reserved for limited indications. PMID:25287172

  13. Feasibility, efficacy, and predictive factors for the technical success of endoscopic nasogallbladder drainage: a prospective study.

    PubMed

    Yane, Kei; Maguchi, Hiroyuki; Katanuma, Akio; Takahashi, Kuniyuki; Osanai, Manabu; Kin, Toshifumi; Takaki, Ryo; Matsumoto, Kazuyuki; Gon, Katsushige; Matsumori, Tomoaki; Tomonari, Akiko; Nojima, Masanori

    2015-03-01

    Several studies have shown the useful-ness of endoscopic nasogallbladder drainage (ENGBD) in patients with acute cholecystitis. However, the procedure is difficult, and factors that affect technical success have not yet been clarified. We conducted a prospective study to eval-uate the technical feasibility, efficacy, and predictive factors for the technical success of ENGBD in patients with acute cholecystitis. All patients with moderate or severe acute cholecystitis who were enrolled underwent ENGBD between April 2009 and April 2011. Patients with surgically altered anatomy or pancreatobiliary malignancies were ex-cluded. The primary outcomes included technical success, clinical success, and complications. Factors that could affect the technical success were also examined. Of the 27 patients who underwent ENGBD during the study period, technical success was achieved in 21 (78%) and clinical improvement was achieved in 20 (95%). Early complications were encountered in four patients (15%). Gallbladder wall thickness (odds ratio [OR], 1.64; 95% confidence interval [CI], 1.08 to 2.47) and age (OR, 1.16; 95% CI, 1.00 to 1.35) were effective predictors of technical failure. ENGBD was effective in resolving acute cholecystitis; however, this modality was technically challenging and had a limited suc-cess rate. Because of technical difficulties, ENGBD should be reserved for limited indications. (Gut Liver, 2015;9239-246).

  14. 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…

  15. 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.

  16. Educational Choice Regarding Technical Education: Research with Case Study

    ERIC Educational Resources Information Center

    Kacerauskas, Tomas; Šaparauskas, Jonas

    2017-01-01

    In first part, the models, theories, mechanisms and presumptions, as well as the ideas of educational choice discourse have been scrutinized. In the second part, the survey on educational choice at Vilnius Gediminas Technical University, Lithuania has been presented. The methodology used in this research is a survey of respondents and survey…

  17. Cohesive mechanism of the FeCr/Ni Interface: A first-principles study

    NASA Astrophysics Data System (ADS)

    Tan, Yong; Zheng, Haizhong; Li, Guifa; Xiong, Lingling; Peng, Ping

    2016-01-01

    Based on previous experimental results, a series of FeCr/Ni interface models have been constructed and analyzed using a first-principles pseudopotential plane-wave method. Several parameters, such as the ideal work of separation ( W), formation enthalpy (Δ H), cohesive energy (Δ E), and electronic structure were calculated in order to analyze the bonding performance and adhesion mechanisms of elements along an FeCr/Ni interface. The largest ideal work of separation was obtained for the Fe(100)/Ni(100) interface, which implies that this interface model presented the most stable structure among a series of crystal interface indices, e.g., (100), (110), and (111). With Cr doping, the W of the FeCr(100)/Ni(100) interface was increased by 101.571 mJ/m2. The corresponding ΔH and ΔE values also indicated that the FeCr(100)/Ni(100) interface model was strengthened by doping with chromium. Furthermore, the overlap population ratio, R LBOP ( R LBOP= 1.04), of FeCr(100)/Ni(100) was smaller than that of Fe(100)/Ni(100) ( R LBOP = 1.35), which implies that the toughness of the Fe(100)/Ni(100) interface can be improved by the presence of chromium impurities. Moreover, electronic structure analysis provided an understanding of the mechanical performance of the various Fe(Cr)/Ni interface models. Thus, our findings open a potential avenue for the comprehensive study of composite material designs.

  18. Dynamics of crack penetration vs. branching at a weak interface: An experimental study

    NASA Astrophysics Data System (ADS)

    Sundaram, Balamurugan M.; Tippur, Hareesh V.

    2016-11-01

    In this paper, the dynamic crack-interface interactions and the related mechanics of crack penetration vs. branching at a weak interface are studied experimentally. The interface is oriented perpendicular to the incoming mode-I crack in an otherwise homogeneous bilayer. The focus of this investigation is on the effect of interface location and the associated crack-tip parameters within the bilayer on the mechanics of the ensuing fracture behavior based on the optical methodologies laid down in Ref. Sundaram and Tippur (2016). Time-resolved optical measurement of crack-tip deformations, velocity and stress intensity factor histories in different bilayer configurations is performed using Digital Gradient Sensing (DGS) technique in conjunction with high-speed photography. The results show that the crack path selection at the interface and subsequently the second layer are greatly affected by the location of the interface within the geometry. Using optically measured fracture parameters, the mechanics of crack penetration and branching are explained. Counter to the intuition, a dynamically growing mode-I approaching a weak interface at a lower velocity and stress intensity factor penetrates the interface whereas a higher velocity and stress intensity factor counterpart gets trapped by the interface producing branched daughter cracks until they kink out into the next layer. An interesting empirical observation based on measured crack-tip parameters for crack penetration and branching is also made.

  19. A Study of Learning and Retention with a Web-Based IR Interface

    ERIC Educational Resources Information Center

    Ahmed, S. M. Zabed; McKnight, Cliff; Oppenheim, Charles

    2005-01-01

    This article reports on an empirical study on novices' learning and retention with the Web-based interface to the Web of Science. The aim was to evaluate the performance of novice searchers in initially learning to use the search interface and in later use. Their performance in both sessions was measured in terms of time taken to perform tasks,…

  20. Orbital operations study. Volume 2: Interfacing activities analyses. Part 3: Data management activity group

    NASA Technical Reports Server (NTRS)

    Mehrbach, E.; Turkel, S. H.

    1972-01-01

    A summary of the findings of the data management group of the orbital operations study is presented. Element interfaces, alternate approaches, design concepts, operational procedures, functional requirements, design influences, and approach selection are described. The following interfacing activities are considered: (1) communications, (2) rendezvous, (3) stationkeeping, and (4) detached element operations.

  1. 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.

  2. Payload/orbiter contamination control requirement study: Computer interface

    NASA Technical Reports Server (NTRS)

    Bareiss, L. E.; Hooper, V. W.; Ress, E. B.; Strange, D. A.

    1976-01-01

    A preliminary assessment of the computer interface requirements of the Spacelab configuration contamination computer model was conducted to determine the compatibility of the program, as presently formatted, with the computer facilities at MSFC. The necessary Spacelab model modifications are pointed out. The MSFC computer facilities and their future plans are described, and characteristics of the various computers as to availability and suitability for processing the contamination program are discussed. A listing of the CDC 6000 series and UNIVAC 1108 characteristics is presented so that programming requirements can be compared directly and differences noted.

  3. Experimental Study of Electronic States at Metal-Dielectric Interfaces.

    DTIC Science & Technology

    1985-12-23

    interface states but also to explore the magnetic field dependence of the energy levels in n-type InSb - NiSb eutectic. From past experience with donors...bare surface plasmon by an order of magnitude. C. p-type InSb - NiSb Eutectic (1) Spectroscopic Results To grow the two phase semiconductor crystal, one...starts with a eutectic mixture of InSb - NiSb heated above the melting point and then lowers it at constant velocity (e.g., 1 cm/hr) through a steep

  4. A Simulation Study of the Virtual Interface Architecture

    SciTech Connect

    Hu, Tan Chang; Stans, Leonard; Tarman, Thomas D.

    1999-05-18

    The Virtual Interface Architecture (VIA) is an emerging standard for interconnecting commodity computing nodes into a cluster. Since VIA protocol. operations are implemented outside the operating system kernel (often, entirely in hardware), VIA transfers can be performed at very low delay, high throughput, and minimal CPU overhead. This makes VIA ideal when building large clusters that perform complex simulations of physical events, However, the scaling properties of VIA are less clear. This paper describes the design and results of a simulation model developed in OPNET to investigate VIA's ability to scale to clusters of> 1000 nodes.

  5. 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,

  6. Theoretical study of Ge/ BaTiO 3 Interfaces

    NASA Astrophysics Data System (ADS)

    Fredrickson, Kurt; Demkov, Alexander

    2011-03-01

    It has been shown (McKee et al., Phys. Rev. Lett. 81, 3014 (1998), and R. McKee, et al., Science 293 , 468 (2001)) that perovskite oxides SrTi O3 and BaTi O3 (BTO) can be grown epitaxially on Si and Ge, respectively. It would be interesting to achieve the reverse, i.e. to grow for example, Ge on BTO. It is not clear, however, whether one can achieve wetting of BTO by Ge. Theoretically, the energy of the Ge (001) surface is estimated to be anywhere between 591 and 1700 erg/cm2 and the surface energy of BTO is in the range of 1083-1496 erg/cm2 depending on termination and environment. The missing piece of information is the energy of the Ge/BTO interface. We examine five possible Ge/BTO interface structures and calculate their energies using density functional theory to determine which one has the lowest energy, and whether wetting can be achieved.

  7. Repositioning the Facilities in Technical College Workshops for Efficiency: A Case Study of North Central Nigeria

    ERIC Educational Resources Information Center

    Umar, Ibrahim Y.; Ma'aji, Abdullahi S.

    2010-01-01

    This article focuses on assessing the facilities in Government Technical College workshops in the context of a developing country. A descriptive survey design was adopted. Two research questions and a hypothesis were formulated to guide the study. A 35-item questionnaire was developed based on the National Board for Technical Education (NBTE)…

  8. 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…

  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. 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.

  11. 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…

  12. Emergency Management Operations Process Mapping: Public Safety Technical Program Study

    DTIC Science & Technology

    2011-02-01

    contractor and the contents do not necessarily have the approval or endorsement of Defence R&D Canada. Defence Research Development Canada Centre for...further research in the area of emergency management. Using the products as templates, investigation with stakeholders will enable the capture of...authorities from all levels. As a research and analysis tool, it will be used to identify, situate and characterize key interface and decision-making

  13. Colloid and interface chemistry aspects of ceramics. Final technical report, 1 August 1985-31 August 1989

    SciTech Connect

    Matijevic, E.

    1989-11-29

    This comprehensive, long term, interdisciplinary program has a dual purpose: (a) To generate new or better defined dispersed solids as starting materials for controlled microstructures, with special emphasis on electrooptic ceramics, as well as composites that meet armor and antiarmor requirements. (b) To develop a better understanding of interfacial processes responsible for different properties of high performance ceramics. With respect to (a), several powders of simple and mixed composition have been prepared including zirconium, cerium, yttrium, gadolinium, europium, samarium, and terbium compounds. Furthermore, particles of internally mixed composition of Y(III)/Ce(III) and Zr(IV)/Y(III) basic carbonates and oxides in varying molar ratios have been synthesized. Finally, particles of different cores coated with other compounds have been obtained, such as oxides of chromium, iron, and titanium covered with alumina, or of iron oxide coated with zirconia or yttria. The powders so obtained were of narrow size distribution with particles of different morphologies, including spheres. These materials were characterized in terms of their various properties (porosity, optical, magnetic, electrokinetic, etc.). With respect to (b), the studies involved solid/solute and solid/solid interactions. The adsorption of chelating agents on iron oxides was used to affect the surface potential and dissolution of the finely dispersed solids.

  14. 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.

  15. 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.

  16. A numerical model study of the effect of interface shape on particle pushing

    NASA Astrophysics Data System (ADS)

    Agaliotis, Eliana M.; Schvezov, Carlos E.; Rosenberger, Mario R.; Ares, Alicia E.

    2012-09-01

    A numerical model using an axisymmetric approximation is developed to study particle pushing during solidification. The model is applied to determine the effect of different parameters on the predicted critical velocity for engulfment of the particle by the solidifying interface. The main parameters considered are particle radius, interface velocity and interface shape as obtained for different thermal conductivities between matrix and particle. The relative thermal conductivity is very important in the pushing/capture process in increasing or decreasing the critical velocity for pushing one order of magnitude, with respect to the critical velocity for a flat interface, depending on whether the interface is concave or convex. Moreover, the predicted critical velocities cover the span of measured values in agreement with the tendency given by the thermal conductivities and particle radius.

  17. Shape-anisotropic particles at curved fluid interfaces and role of Laplace pressure: a computational study.

    PubMed

    Cheng, Tian-Le; Wang, Yu U

    2013-07-15

    The self-assembly behavior of shape-anisotropic particles at curved fluid interfaces is computationally investigated by diffuse interface field approach (DIFA). A Gibbs-Duhem-type thermodynamic formalism is introduced to treat heterogeneous pressure within the phenomenological model, in agreement with Young-Laplace equation. Computer simulations are performed to study the effects of capillary forces (interfacial tension and Laplace pressure) on particle self-assembly at fluid interfaces in various two-dimensional cases. For isolated particles, it is found that the equilibrium liquid interface remains circular and particles of different shapes do not disturb the homogeneous curvature of liquid interface, while the equilibrium position, orientation and stability of a particle at the liquid interface depend on its shape and initial location with respect to the liquid interface. For interacting particles, the curvature of local liquid interfaces is different from the apparent curvature of the particle shell; nevertheless, irrespective of the particle shapes, a particle-coated droplet always tends to deform into a circular morphology under positive Laplace pressure, loses mechanical stability and collapses under negative Laplace pressure, while adapts to any morphology and stays in neutral equilibrium under zero Laplace pressure. Finally, the collective behaviors of particles and Laplace pressure evolution in bicontinuous interfacially jammed emulsion gels (bijels) are investigated. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Studies on refrigerator sensors and cooling section interface

    NASA Astrophysics Data System (ADS)

    Miyazaki, Yoshirou

    1993-03-01

    The results of a patents examination are outlined including the following items: (1) examination methods and their results concerning the cooling type photoelectric conversion devices; (2) the infrared ray receiver with cooler radiation detector; (3) cryogenic container; (4) the expansion cylinder device; (5) the vibration isolation device for cooling a focal plane; and (6) an infrared detector. The results of users' opinion survey for JEM (Japanese Experiment Module) utilization are summarized as follows: (1) the development of cryogenic (4 K) coolers are strongly desired; (2) pointing device is indispensable for observation system users; (3) vibration condition requirements range from ten micrometer to less than 1 micrometer; (4) miniaturization is strongly desired; and (5) cooler interface is not the image of direct cooling of the sensor but overall cooling of the system. This presentation is represented by viewgraphs only.

  19. Cadmium selenide interface states studied by electrochemical photocapacitance spectroscopy

    SciTech Connect

    Haak, R.; Tench, D.

    1984-06-01

    In this paper, the electrochemical photocapacitance spectroscopy (EPS) method, which involves measuring the differential capacitance for the reverse-biased semiconductor in an electrolyte as a function of incident subbandgap light, was applied to further elucidate the nature of interface states on n-CdSe. This method has been shown to be an unusually sensitive means for characterization of deep levels in various semiconductor materials (4). In aqueous electrolytes, the interfacial oxide structure might be expected to be similar to that formed in the ambient atmosphere. A key goal in the present work was to establish unequivocally the location of the state associated with oxygen adsorption. An alternate interpretation for previous data was that the observed states actually resided in the bulk and were rendered detectable by the enhanced thickness of the semiconductor space-charge layer resulting from the negative surface charge associated with adsorbed oxygen.

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

    NASA Astrophysics Data System (ADS)

    Bradley, D. A.; Kaabar, W.; Gundogdu, O.

    2012-02-01

    The techniques μProton-Induced X-and γ-ray Emission, μ-PIXE and μ-PIGE, were used to investigate trace and essential element distributions in sections of normal and osteoarthritic (OA) human femoral head. μ-PIGE yielded 2-D mappings of Na and F while Ca, Z, P and S were mapped by μ-PIXE. The concentration of chondroitin sulphate supporting functionality in healthy cartilage is significantly reduced in OA samples. Localised Zn points to osteoblastic/osteoclastic activity at the bone-cartilage interface. Small-angle X-ray scattering applied to decalcified OA-affected tissue showed spatial alterations of collagen fibres of decreased axial periodicity compared to normal collagen type I.

  1. Acquisition of a Circular Dichroism Spectrometer to Study Biological Molecules at Interfaces

    DTIC Science & Technology

    2016-02-10

    02-2016 15-Jul-2014 14-Jan-2016 Final Report: Acquisition of a Circular Dichroism Spectrometer to Study Biological Molecules at Interfaces The views...Circular Dichroism Spectrometer to Study Biological Molecules at Interfaces Report Title We have made substantial progress in the design, implementation, and...1 Grant Information Award Number W911NF-14-1-0413 Title of Research Acquisition of a Circular Dichroism (CD) Spectrometer to Study

  2. The FERMI @ Elettra Technical Optimization Study: PreliminaryParameter Set and Initial Studies

    SciTech Connect

    Byrd, John; Corlett, John; Doolittle, Larry; Fawley, William; Lidia, Steven; Penn, Gregory; Ratti, Alex; Staples, John; Wilcox,Russell; Wurtele, Jonathan; Zholents, Alexander

    2005-08-01

    The goal of the FERMI {at} Elettra Technical Optimization Study is to produce a machine design and layout consistent with user needs for radiation in the approximate ranges 100 nm to 40 nm, and 40 nm to 10 nm, using seeded FEL's. The Study will involve collaboration between Italian and US physicists and engineers, and will form the basis for the engineering design and the cost estimation.

  3. Technical efficiency analysis for oilseed sunflower farms: a case study in Erzurum, Turkey.

    PubMed

    Külekçi, Murat

    2010-07-01

    The main purpose of this study was to examine the technical efficiency of farms producing sunflower in Erzurum, Turkey and to identify factors that might be causing inefficiency. Stochastic frontier analysis was used to measure technical efficiency. One hundred and seventeen randomly selected farms were interviewed for farm-level data in the 2004-2005 production period. Results revealed that the mean technical efficiency for the sunflower farms, estimated by the stochastic production frontier, is 64%. At full technical efficiency, on average, the farmers could reduce their inputs by around 56% without reducing their sunflower production, simply by improving technical efficiency. In the inefficiency model the parameter estimates showed that older farmers, higher level of farmer's education, more experienced farmers, larger farm size and higher information score resulted in lower technical inefficiency, while bigger family size and more credit usage resulted in higher technical inefficiency. This study proposes strategies such as providing better extension services and farmer-training programmes, including more educated people in sunflower farming and also expanding the sunflower-growing area through provision of adequate facilities in order to increase technical efficiency.

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

    PubMed

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

    2014-12-01

    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. 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. 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. 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. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights

  5. 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

  6. 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.

  7. [A technic using MRI. A comparative study of 3 anesthetic technics of the inferior alveolar nerve].

    PubMed

    Libersa, P; Dujardin, S; Francke, J P; Libersa, J C; Pertuzon, B

    1999-01-01

    In our study we used M.R. sectional imaging in the axial and coronal planes to investigate three alveolar nerve anaesthesia techniques: Gow Gates, Akinosi and Classical techniques. Furthermore, anatomic sections were made using cadaveric specimens in axial and coronal planes to visualize anatomical relations of the anaesthetic drug. The present study showed the more or less important and quick spreading of the anaesthetic drug through the infra temporal area depending on the anaesthesia technique. Possible incidents are also discussed.

  8. 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.

  9. Energy Source Study Technical Report for Deployable Acoustic Projector System (DAPS)

    DTIC Science & Technology

    1988-12-23

    S SPARTON"- AD-A278 879 7097-0001-1192 ENERGY SOURCE STUDY TECHNICAL REPORT FOR DEPLOYABLE ACOUSTIC PROJECTOR SYSTEM (DAPS) Contract N62190-88-M...SUBTITLE 5. FUNDING NUMBERS Energy Source Study Technical Report for Deployable C:N62190-88-q+0755 Acoustic Projector System (DAPS) 6. AUTHOR(S) 7...Rev 2-89) P~IýAIppd by ill* 164 it- IJs IL- 3 Fst’ rPAITON OWiENSE mac vrroNcS r 7097-0001-1192 ENERGY SOURCE STUDY TECHNICAL REPORT I FOR DEPLOYABLE

  10. 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…

  11. 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.

  12. 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.

  13. Three phase interfaces at electrified metal-solid electrolyte systems I. study of the Pt(hkl)-Nafion interface.

    SciTech Connect

    Subbaraman, R.; Strmcnik, D.; Stamenkovic, V.; Markovic, N. M.

    2010-01-01

    A voltammetric fingerprinting approach has been used to probe the nature of Pt-Nafion three phase interfaces for Pt(hkl) and polycrystalline platinum surfaces. Nature of adsorbing species is identified as the sulfonate anions via CO charge displacement technique. The affinity for the sulfonate anions to adsorb on the electrode surface is investigated. Adsorption strength of the sulfonate anions with the electrode surface is compared with other strongly adsorbing anions such as (bi) sulfates and chlorides. Various factors that influence the adsorption properties of the sulfonate anions are studied. Nature and strength of the anion interaction with various surface geometries is also discussed. A physical model is presented to describe the observed phenomena.

  14. 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.

  15. 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.

  16. 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.

  17. A study of usability principles and interface design for mobile e-books.

    PubMed

    Wang, Chao-Ming; Huang, Ching-Hua

    2015-01-01

    This study examined usability principles and interface designs in order to understand the relationship between the intentions of mobile e-book interface designs and users' perceptions. First, this study summarised 4 usability principles and 16 interface attributes, in order to conduct usability testing and questionnaire survey by referring to Nielsen (1993), Norman (2002), and Yeh (2010), who proposed the usability principles. Second, this study used the interviews to explore the perceptions and behaviours of user operations through senior users of multi-touch prototype devices. The results of this study are as follows: (1) users' behaviour of operating an interactive interface is related to user prior experience; (2) users' rating of the visibility principle is related to users' subjective perception but not related to user prior experience; however, users' ratings of the ease, efficiency, and enjoyment principles are related to user prior experience; (3) the interview survey reveals that the key attributes affecting users' behaviour of operating an interface include aesthetics, achievement, and friendliness. This study conducts experiments to explore the effects of users’ prior multi-touch experience on users’ behaviour of operating a mobile e-book interface and users’ rating of usability principles. Both qualitative and quantitative data analyses were performed. By applying protocol analysis, key attributes affecting users’ behaviour of operation were determined.

  18. Spatial scanning spectroelectrochemistry. Study of the electrodeposition of Pd nanoparticles at the liquid/liquid interface.

    PubMed

    Izquierdo, Daniel; Martinez, Alberto; Heras, Aranzazu; Lopez-Palacios, Jesus; Ruiz, Virginia; Dryfe, Robert A W; Colina, Alvaro

    2012-07-03

    Spatial scanning spectroelectrochemistry is a new analytical technique that provides spectral information at different distances from an electrified liquid/liquid interface where an electrochemical process takes place. As a proof of concept, we have studied two different electrochemical processes at the electrified liquid/liquid interface: (1) Ru(bpy)(3)(2+) transfer through the water/1,2-dichloroethane interface and (2) electrodeposition of Pd nanoparticles at the water/1,2-dichloroethane interface. The instrumental setup developed consists of a movable slit for the light beam to sample at well-defined positions on both sides of the interface, providing important information about the chemical process occurring. If the slit is scanned at different distances from the interface during an electrochemical experiment, a complete picture of the reactions and equilibria in the diffusion layer can be obtained. For example, in the case of the Ru(bpy)(3)(2+), the experiments show clearly how the complex is transferred from one phase to the other. In the case of electrosynthesis of Pd nanoparticles, it is demonstrated that nanoparticles are not only deposited at the interface but diffuse to the aqueous bulk solution. These in situ observations were confirmed by ex situ experiments using transmission electron microscopy.

  19. Molecular theory on dielectric constant at interfaces: a molecular dynamics study of the water/vapor interface.

    PubMed

    Shiratori, Kazuya; Morita, Akihiro

    2011-06-21

    Though the local dielectric constant at interfaces is an important phenomenological parameter in the analysis of surface spectroscopy, its microscopic definition has been uncertain. Here, we present a full molecular theory on the local field at interfaces with the help of molecular dynamics simulation, and thereby provide microscopic basis for the local dielectric constant so as to be consistent to the phenomenological three-layer model of interface systems. To demonstrate its performance, we applied the theory to the water/vapor interface, and obtained the local field properties near the interface where the simple dielectric model breaks down. Some computational issues pertinent to Ewald calculations of the dielectric properties are also discussed. © 2011 American Institute of Physics

  20. Commingled uranium-tailings study. Volume II. Technical report

    SciTech Connect

    1982-06-30

    Public Law 96-540, Section 213, directs the Secretary of Energy to develop a plan for a cooperative program to provide assistance in the stabilization and management of defense-related uranium mill tailings commingled with other tailings. In developing the plan, the Secretary is further directed to: (1) establish the amount and condition of tailings generated under federal contracts; (2) examine appropriate methodologies for establishing the extent of federal assistance; and (3) consult with the owners and operators of each site. This technical report summarizes US Department of Energy (DOE) and contractor activities in pursuit of items (1), (2), and (3) above. Recommendations regarding policy and a cooperative plan for federal assistance are under separate cover as Volume I.

  1. Product functions: interfaces with ergonomic design.

    PubMed

    Campos, Lívia F de A; Lanutti, Jamille N de L; Paschoarelli, Luis Carlos

    2012-01-01

    In addition to technical quality, increasing emphasis is being placed on the importance of elements such as the appearance and meaning of products. To be successful, therefore, attention must be paid to the aesthetic and symbolic functions of objects as well as to reliability and physical quality. Study of the interfaces of these functions may provide a theoretical basis for the ergonomic design of products. The objective of this review is to attempt to establish the nature of these interfaces.

  2. A comparison study of visually stimulated brain-computer and eye-tracking interfaces.

    PubMed

    Suefusa, Kaori; Tanaka, Toshihisa

    2017-06-01

    Brain-computer interfacing (BCI) based on visual stimuli detects the target on a screen on which a user is focusing. The detection of the gazing target can be achieved by tracking gaze positions with a video camera, which is called eye-tracking or eye-tracking interfaces (ETIs). The two types of interface have been developed in different communities. Thus, little work on a comprehensive comparison between these two types of interface has been reported. This paper quantitatively compares the performance of these two interfaces on the same experimental platform. Specifically, our study is focused on two major paradigms of BCI and ETI: steady-state visual evoked potential-based BCIs and dwelling-based ETIs. Recognition accuracy and the information transfer rate were measured by giving subjects the task of selecting one of four targets by gazing at it. The targets were displayed in three different sizes (with sides 20, 40 and 60 mm long) to evaluate performance with respect to the target size. The experimental results showed that the BCI was comparable to the ETI in terms of accuracy and the information transfer rate. In particular, when the size of a target was relatively small, the BCI had significantly better performance than the ETI. The results on which of the two interfaces works better in different situations would not only enable us to improve the design of the interfaces but would also allow for the appropriate choice of interface based on the situation. Specifically, one can choose an interface based on the size of the screen that displays the targets.

  3. A comparison study of visually stimulated brain-computer and eye-tracking interfaces

    NASA Astrophysics Data System (ADS)

    Suefusa, Kaori; Tanaka, Toshihisa

    2017-06-01

    Objective. Brain-computer interfacing (BCI) based on visual stimuli detects the target on a screen on which a user is focusing. The detection of the gazing target can be achieved by tracking gaze positions with a video camera, which is called eye-tracking or eye-tracking interfaces (ETIs). The two types of interface have been developed in different communities. Thus, little work on a comprehensive comparison between these two types of interface has been reported. This paper quantitatively compares the performance of these two interfaces on the same experimental platform. Specifically, our study is focused on two major paradigms of BCI and ETI: steady-state visual evoked potential-based BCIs and dwelling-based ETIs. Approach. Recognition accuracy and the information transfer rate were measured by giving subjects the task of selecting one of four targets by gazing at it. The targets were displayed in three different sizes (with sides 20, 40 and 60 mm long) to evaluate performance with respect to the target size. Main results. The experimental results showed that the BCI was comparable to the ETI in terms of accuracy and the information transfer rate. In particular, when the size of a target was relatively small, the BCI had significantly better performance than the ETI. Significance. The results on which of the two interfaces works better in different situations would not only enable us to improve the design of the interfaces but would also allow for the appropriate choice of interface based on the situation. Specifically, one can choose an interface based on the size of the screen that displays the targets.

  4. Factors that influence the non-technical skills performance of scrub nurses: a prospective study.

    PubMed

    Kang, Evelyn; Massey, Debbie; Gillespie, Brigid M

    2015-12-01

    To identify and describe the factors that impact on the performance of scrub nurses' non-technical skills performance during the intra-operative phase of surgery. Non-technical skills have been identified as important precursors to errors in the operating room. However, few studies have investigated factors influencing non-technical skills of scrub nurses. Prospective observational study. Structured observations were performed on a sample of 182 surgical procedures across eight specialities by two trained observers from August 2012-April 2013 at two hospital sites. Participants were purposively selected scrub nurses. Bivariate correlations and a multiple linear regression model were used to identify associations among length of surgery, patients' acuity using the American Society of Anesthesiologists classification system, team familiarity, number of occasions scout nurses leave the operating room, change of scout nurse and the outcome, the non-technical skills performance of scrub nurses. Patient acuity and team familiarity were the strongest predictors of scrub nurses' non-technical skills performance at hospital site A. There were no correlations between the predictors and the performance of scrub nurses at hospital site B. A dedicated surgical team and patient acuity potentially influence the performance of scrub nurses' non-technical skills. Familiarity with team members foster advanced planning, thus minimizing distractions and interruptions that impact on scrub nurses' performance. Development of interventions aimed at improving non-technical skills has the potential to make a substantial difference and enhance patient care. © 2015 John Wiley & Sons Ltd.

  5. In vivo measurement of compression bandage interface pressures: the first study.

    PubMed

    Rimaud, D; Convert, R; Calmels, P

    2014-01-01

    Compression therapy has precise technical characteristics but in vivo pressures exerted by bandages are still poorly understood. To perform in vivo pressure measurements of different compression bandages bearing different technical characteristics with different application methods. Interface pressure was measured on the lower limb of 20 healthy women at 3 different points (B1, C and F) using 6 compression techniques (stockings, non-elastic bandage, elastic bandages with 2 technical characteristics and 3 application methods), and in 3 positions. All elastic compression bandages respected the principle of graduated pressure along the length of the limb (P<0.0001), but not the non-elastic bandage. The pressures increase significantly (P<0.0001) between the supine position and the sitting or standing position, especially with the non-elastic compression bandage. There is a marked variation in pressures between subjects for some bandages (non-elastic and elastic applied using the figure-of-eight technique). The pressure increases significantly with the number of bandage overlaps (P<0.01). Elastic and non-elastic bandages behave differently from one another, and non-elastic bandages not appearing to comply with medical recommendations concerning graduated pressure. There is a high level of variability between subjects for some compression bandages (non-elastic and figure-of-eight methods). Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  6. 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.

  7. The Development of Technical and Vocational Education in Indonesia--A Case Study in Quality Improvement. Case Studies on Technical and Vocational Education in Asia and the Pacific.

    ERIC Educational Resources Information Center

    Bakri, Mohamad

    After its independence in 1969, Indonesia studied and analyzed its previous colonial system of technical and vocational education (TVE) and took steps to overcome the shortcomings. TVE was required to provide expansion of work opportunities and industrial development to promote national development. Until 1989, attention was given to further…

  8. Mechanical Strength of Silicon/Silicon Nitride Interfaces: A Molecular-Dynamics Study

    NASA Astrophysics Data System (ADS)

    Bachlechner, Martina E.; Knudsen, Steven R.; Schiffbauer, Jarrod E.; Wang, Ye; Zhang, Jennifer; Korakakis, Dimitris

    2004-03-01

    Molecular-dynamics simulations are performed on parallel computers to investigate failure mechanisms of the crystalline Si(111)/Si_3N_4(0001) interface as strain is applied parallel to the interface. Comparisons between different rates of strain and temperatures were studied. Increased temperatures were found to have an adverse effect on the mechanical strength of the material, and increased rates of strain caused the system to fail later than those that were stretched more slowly.

  9. 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.

  10. Study of the P3HT/PCBM interface using photoemission yield spectroscopy

    NASA Astrophysics Data System (ADS)

    Grzibovskis, Raitis; Vembris, Aivars

    2016-04-01

    Photogeneration efficiency and charge carrier extraction from active layer are the parameters that determine the efficiency of organic photovoltaics (OPVs). Devices made of organic materials often consist of thin (up to 100nm) layers. At this thickness different interface effects become more pronounced. The electron affinity and ionization energy shift can affect the charge carrier transport across metal-organic interface which can affect the performance of the entire device. In the case of multilayer OPVs, energy level compatibility at the organic-organic interface is as important. Photoemission yield spectroscopy was used for organic-organic interface study by ionization energy measurements. In this work we studied "sandwich" type samples of two well-known organic photovoltaic materials- poly(3- hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM). Ionization energy changes at the P3HT/PCBM interface depending on PCBM layer thickness were studied. P3HT layer was obtained by spin-coating while PCBM was deposited on the P3HT by thermal evaporation in vacuum. No ionization energy shift of P3HT was observed. On the contrary, PCBM at the interface with P3HT created additional 0.40eV barrier for hole transport from PCBM to P3HT.

  11. 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

  12. Thermal conductivity study at CH/Be interface by refraction-enhanced x-ray radiography

    NASA Astrophysics Data System (ADS)

    Ping, Yuan; Landen, Otto; Koch, Jeff; Hicks, Damien; Wallace, Russel; Collins, Gilbert

    2012-10-01

    Transport properties near the fuel-ablator interface at the edge of an ICF capsule are important for modeling the growth of hydrodynamic instabilities, which determines the mix level in the fuel and is critical for successful ignition (Hammel, et al. HEDP 6, 671, 2010). A novel technique, time-resolved refraction-enhanced x-ray radiography, is developed to study thermal conductivity at the interface (Ping et al. J. Instru. 2011). Experiments using OMEGA laser have been carried out for CH/Be targets isochorically heated by x-rays to measure the evolution of the density gradient at the interface due to thermal conduction. The sensitivity of this radiographic technique to discontinuities enabled observation of shock/rarefraction waves propagating away from the interface. Comparison of data and simulation results using various conductivity models will be presented.

  13. 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.

  14. A study of the interface strength between protein and mineral in biological materials.

    PubMed

    Ji, Baohua

    2008-01-01

    Bone, tooth, mineralized tendon and sea shells are nanocomposites of protein and mineral with superior mechanical properties. As the mineral is so small at nanoscale, the volume fraction of the protein-mineral interface in the bulk materials can be enormously large; therefore, the mechanics of the interface should be critically important for the integrity of these biomaterials. Currently, people do not have a good understanding of the interface between protein and mineral, a hybrid interface between organic and inorganic constituents in biological materials. In this paper, a tension-shear chain (TSC) model is introduced into the Dugdale model for estimating the fracture energy of biomaterials. The strength of the hybrid interface is then studied with a "soft-hard" bi-layer fracture model, by which we find for the first time that the interface strength depends on both the size and geometry of the mineral crystal, and has been highly optimized through the miniaturization of mineral at nanoscale. This study may provide important insights into the mechanics of bone and tooth at small scale for tissue engineering in biomedical applications.

  15. 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.

  16. 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:…

  17. A Case Study in Locating the Architectural Roots of Technical Debt

    DTIC Science & Technology

    2015-01-16

    architects is that architectural technical debt is extremely common. Like rust, it never sleeps ; it just accumulates in projects, unless some conscious...A Case Study in Locating the Architectural Roots of Technical Debt Rick Kazman∗, Yuanfang Cai‡, Ran Mo‡, Qiong Feng‡, Lu Xiao‡, Serge Haziyev...shown that, in large-scale software systems, defective files seldom exist alone. They are usually architecturally connected, and their architectural struc

  18. Conditioning of Si-interfaces by wet-chemical oxidation: Electronic interface properties study by surface photovoltage measurements

    NASA Astrophysics Data System (ADS)

    Angermann, Heike

    2014-09-01

    The field-modulated surface photovoltage (SPV) method, a very surface sensitive technique, was utilized to determine electronic interface properties on wet-chemically oxidized and etched silicon (Si) interfaces. The influence of preparation-induced surface micro-roughness and un-stoichiometric oxides on the resulting the surface charge, energetic distribution Dit(E), and density Dit,min of rechargeable states was studied by simultaneous, spectroscopic ellipsometry (SE) measurements on polished Si(111) and Si(100) substrates. Based on previous findings and new research, a study of conventional and newly developed wet-chemical oxidation methods was established, correlating the interactions between involved oxidizing and etching solutions and the initial substrate morphology to the final surface conditioning. It is shown, which sequences of wet-chemical oxidation and oxide removal, have to be combined in order to achieve atomically smooth, hydrogen terminated surfaces, as well as ultra-thin oxide layers with low densities of rechargeable states on flat, saw damage etched, and textured Si substrates, as commonly applied in silicon device and solar cell manufacturing. These conventional strategies for wet-chemical pre-treatment are mainly based on concentrated solutions. Therefore, special attention was put on the development of more environmentally acceptable processes, utilizing e.g. hot pure water with low contents of oxygen or hydrochloric acid, and of ozone, working at ambient temperatures. According to our results, these methods could be a high quality and low cost alternative to current approaches with liquid chemicals for the preparation of hydrophobic Si substrate surfaces and ultra-thin passivating oxide layers. As demonstrated for selected examples, the effect of optimized wet-chemical pre-treatments can be preserved during subsequent soft plasma enhanced chemical vapor depositions of Si oxides (SiOx), or amorphous materials such as Si (a-Si:H), Si nitride (a

  19. 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

  20. Interface chemistry of CdZnTe films studied by a peel-off approach

    NASA Astrophysics Data System (ADS)

    Tao, Jun; Xu, Haitao; Zhang, Yuelu; Ji, Huanhuan; Xu, Run; Huang, Jian; Zhang, Jijun; Liang, Xiaoyan; Tang, Ke; Wang, Linjun

    2016-12-01

    CdZnTe films with thickness above 50 μm were deposited at temperatures of 200-500 °C by Close Space Sublimation method. A peel-off approach has been adopted to study the interface chemistry of CdZnTe thick films. For all the CdZnTe films, the scanning electron microscopy images show the small and round-like grains formed at interface in contrast to the large ordered grains at surface. For CdZnTe films grown at a low substrate temperature of 200 °C, the interface layer between CdZnTe and substrate is mixed with Te and CdTe, as evidenced by X-ray diffraction, Raman and X-ray photoelectron spectroscopy results. The thickness of the interface layer can be estimated to be 84 nm by depth profile using X-ray photoelectron spectroscopy. In contrast, a thin interface layer less than 14 nm is found at a high substrate temperature of 500 °C. The limited reaction of Te2 and Cd (Zn) to CdZnTe at a low growth temperature is responsible for the formation of the thick interface layer and a slow deposition rate at the nucleation stage.

  1. Analytical study of excitation and measurement of fluid-solid interface waves

    NASA Astrophysics Data System (ADS)

    Zhu, Jinying; Popovics, John S.

    2006-05-01

    Analytical analyses are performed to investigate the pressure and particle velocity responses in fluid/solid half spaces subject to impulsive sources. This study has significance for underwater seabed characterization efforts that use interface waves. Results show that pressure (e.g., measured by hydrophones) in the fluid is more sensitive for interface wave sensing than particle velocity (e.g., measured by geophones) at the fluid-solid interface. Both types of impulsive point wave sources, explosive action in fluid and mechanical action on solid, are investigated with regard to the excitability of interface waves. Analyses show that a mechanical load applied normal to the interface generates higher amplitude interface waves, relative to the acoustic wave amplitude, than an explosive load in the fluid. The effect of explosive source height is also investigated. Results show that Scholte wave amplitude is affected by the explosive source height, and decays quickly with increasing height. However, explosive source height has little effect on generated leaky Rayeligh wave amplitude.

  2. 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.

  3. 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…

  4. 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…

  5. Thinking ahead of the surgeon. An interview study to identify scrub nurses' non-technical skills.

    PubMed

    Mitchell, Lucy; Flin, Rhona; Yule, Steven; Mitchell, Janet; Coutts, Kathy; Youngson, George

    2011-07-01

    Efforts to reduce adverse event rates in healthcare have revealed the importance of identifying the essential non-technical (cognitive and social) skills for safe and effective performance. Previous research on non-technical skills for operating theatre staff has concentrated on doctors rather than nursing professionals. The aim of the study was to identify the critical non-technical skills that are essential for safe and effective performance as an operating theatre scrub nurse. Experienced scrub nurses (n = 25) and consultant surgeons (n = 9) from four Scottish hospitals were interviewed using a semi-structured format. The protocols were designed to identify the main social and cognitive skills required by scrub nurses. Interviews were digitally recorded, transcribed verbatim and independently coded to extract behaviours in order to produce a list of the main non-technical skills for safe and effective scrub nurse performance. The non-technical skills of situation awareness, communication, teamwork, task management and coping with stress were identified as key to successful scrub nurse task performance. Component sets of behaviours for each of these categories were also noted. The interviews with subject matter experts from scrub nursing and surgery produced preliminary evidence that situation awareness, communication, teamwork and coping with stress are the principal non-technical skills required for effective performance as a scrub nurse. Copyright © 2010 Elsevier Ltd. All rights reserved.

  6. 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.

  7. 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.

  8. 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.

  9. Use of technical skills and medical devices among new registered nurses: A questionnaire study.

    PubMed

    Ewertsson, Mona; Gustafsson, Margareta; Blomberg, Karin; Holmström, Inger K; Allvin, Renée

    2015-12-01

    One comprehensive part of nursing practice is performing technical skills and handling of medical equipment. This might be challenging for new registered nurses (RNs) to do in patient-safe way. The aim of this study was to describe and compare the extent to which new RNs perform various technical skills and handle medical devices in different settings, and to investigate their possibility for continued learning in this respect. A further aim was to describe their perceptions of incident reporting related to technical skills and medical devices. A cross-sectional study with descriptive and comparative design. RNs who recently graduated from a nursing programme at three Swedish universities and had worked as a RN for up to 1 year were included in the study (n=113, response rate 57%). Data were collected by means of a postal questionnaire. Half of the RNs reported that they performed several of the listed tasks every day or every week, regardless of workplace. These tasks were most frequently performed in surgical departments. The majority of the participants (76%) stated a need of continued practical training. However, less than half of them (48%) had access to a training environment. Several participants (43%) had been involved in incidents related to technical skills or medical devices, which were not always reported. Nearly a third of the participants (31%) did not use the existing guidelines when performing technical skills, and reflection on performance was uncommon. This study highlights the importance of shared responsibilities between nurse educators and health care employers to provide learning opportunities for new RNs in technical skills, to maintain patient safety. To increase the safety culture where nursing students and new RNs understand the importance of using evidence-based guidelines and taking a reflective approach in the performance of technical tasks is needed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Interfaces in polymer nanocomposites – An NMR study

    SciTech Connect

    Böhme, Ute; Scheler, Ulrich

    2016-03-09

    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. {sup 1}H relaxation NMR gives insight on the polymer dynamics over a wide range of correlation times. For the polymer chain dynamics the transverse relaxation time T{sub 2} is most suited. In this presentation we report on two applications of T{sub 2} 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.

  11. The Use of Infrared Methods to Study Polymer Interfaces.

    DTIC Science & Technology

    1982-12-09

    face species and thin films on metal surfaces are obtained by reflection from the metal surface. The RA technique was developed by Francis and Ellison...add little to the RA spectra of most coatings on metal substrates. RA spectroscopy can be used to study both thin films (monolayers and less) and...the sample is the film - substrate (metal) combination. For optimum conditions, it has been shown (26,36) that a reflection spectrum of a thin film can

  12. Model studies of Rayleigh instabilities via microdesigned interfaces

    SciTech Connect

    Glaeser, Andreas M.

    2000-10-17

    The energetic and kinetic properties of surfaces play a critical role in defining the microstructural changes that occur during sintering and high-temperature use of ceramics. Characterization of surface diffusion in ceramics is particularly difficult, and significant variations in reported values of surface diffusivities arise even in well-studied systems. Effects of impurities, surface energy anisotropy, and the onset of surface attachment limited kinetics (SALK) are believed to contribute to this variability. An overview of the use of Rayleigh instabilities as a means of characterizing surface diffusivities is presented. The development of models of morphological evolution that account for effects of surface energy anisotropy is reviewed, and the potential interplay between impurities and surface energy anisotropy is addressed. The status of experimental studies of Rayleigh instabilities in sapphire utilizing lithographically introduced pore channels of controlled geometry and crystallography is summarized. Results of model studies indicate that impurities can significantly influence both the spatial and temporal characteristics of Rayleigh instabilities; this is attributed at least in part to impurity effects on the surface energy anisotropy. Related model experiments indicate that the onset of SALK may also contribute significantly to apparent variations in surface diffusion coefficients.

  13. 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.

  14. A first principles study of adhesion and electronic structure at Fe (110)/graphite (0001) interface

    NASA Astrophysics Data System (ADS)

    Liu, Yangzhen; Xing, Jiandong; Li, Yefei; Sun, Liang; Wang, Yong

    2017-05-01

    Using first-principles calculations, we discuss the bulk properties of bcc Fe and graphite and that of the surface, the work of adhesion, and the electronic structure of Fe (110)/graphite (0001) interface. In this study, the experimental results of the bulk properties of bcc Fe and graphite reveal that our adopted parameters are reliable. Moreover, the results of surface energy demonstrate that nine atomic layers of graphite (0001) and five atomic layers of Fe (110) exhibit bulk-like interiors. The lattice mismatch of Fe (110)/graphite (0001) interface is about 6%. The results also exhibit that the Fe atom residing on top of the second layer of graphite slab (HCP structure) is the preferred stacking sequence. The work of adhesion (Wad) of the optimized Fe/graphite interface of HCP structure is 1.36 J/m2. Electronic structures indicate that the bonding characteristics are a mixture of covalent and ionic bonds in the HCP interface. Moreover, the magnetic moment of atoms at the interface was studied using the spin polarized density of states.

  15. 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.

  16. 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.

  17. Detector-accelerator interface studies at the Tevatron

    SciTech Connect

    Drozhdin, A.I.; Mokhov, N.V.

    1998-04-10

    A summary of studies is presented towards minimization of beam loss in the critical locations at the Fermilab Tevatron to reduce background rates in the collider detectors and to protect machine components. Based on detailed Monte-Carlo simulations, measures have been proposed and incorporated in the machine to reduce accelerator-related instantaneous and residual background levels in the D0 and CDF detectors. Measurements performed are in good agreement with the predictions. Most recent results on acceptance and background rates in the D0 and CDF forward detectors are presented and discussed in detail.

  18. Integrating Virtual Worlds with Tangible User Interfaces for Teaching Mathematics: A Pilot Study

    PubMed Central

    Guerrero, Graciela; Ayala, Andrés; Mateu, Juan; Casades, Laura; Alamán, Xavier

    2016-01-01

    This article presents a pilot study of the use of two new tangible interfaces and virtual worlds for teaching geometry in a secondary school. The first tangible device allows the user to control a virtual object in six degrees of freedom. The second tangible device is used to modify virtual objects, changing attributes such as position, size, rotation and color. A pilot study on using these devices was carried out at the “Florida Secundaria” high school. A virtual world was built where students used the tangible interfaces to manipulate geometrical figures in order to learn different geometrical concepts. The pilot experiment results suggest that the use of tangible interfaces and virtual worlds allowed a more meaningful learning (concepts learnt were more durable). PMID:27792132

  19. Integrating Virtual Worlds with Tangible User Interfaces for Teaching Mathematics: A Pilot Study.

    PubMed

    Guerrero, Graciela; Ayala, Andrés; Mateu, Juan; Casades, Laura; Alamán, Xavier

    2016-10-25

    This article presents a pilot study of the use of two new tangible interfaces and virtual worlds for teaching geometry in a secondary school. The first tangible device allows the user to control a virtual object in six degrees of freedom. The second tangible device is used to modify virtual objects, changing attributes such as position, size, rotation and color. A pilot study on using these devices was carried out at the "Florida Secundaria" high school. A virtual world was built where students used the tangible interfaces to manipulate geometrical figures in order to learn different geometrical concepts. The pilot experiment results suggest that the use of tangible interfaces and virtual worlds allowed a more meaningful learning (concepts learnt were more durable).

  20. 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.

  1. A technical platform for environments for ageing--lessons learned from three field studies.

    PubMed

    Eichelberg, Marco; Büsching, Felix; Steen, Enno-Edzard; Helmer, Axel; Thiel, Andreas; Hein, Andreas; Wolf, Lars

    2014-01-01

    The Lower Saxony Research Network "Design of Environments for Ageing" (GAL) studied possible applications of assistive technology for enabling older adults to live longer and independent in their own home. As part of this work, a technical platform was developed as a common technical basis for all assistive systems in the project. This article presents an overview of the architecture and core functionality of the technical platform, which in the first generation was developed for use in a laboratory setting, and in a second generation was extended for use in the project's field studies, i.e. prototype installations in end-users homes. The field studies' primary objective was the evaluation of the assistive technologies, that were developed within the overall project. However, these studies also confirmed that the fundamental concept of the technical platform is valid, and the prototypes continuously worked 24 h a day for several months. However, there were some problems related to lack of infrastructure in the older adults' homes and human factors such as inadvertent placement of objects across sensors' field of view, acceptance problems due to aesthetical reasons or simply communication problems, which show that making complex technologies work for users with little technical experience is well possible, but requires a careful consideration of the complete service chain and related "soft factors".

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    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.

  3. 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

  4. 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…

  5. 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…

  6. Chinese/Japanese Input Feasibility Study. Final Technical Report.

    ERIC Educational Resources Information Center

    Desautels, John E.; And Others

    A study was conducted to determine the feasibility of developing an automatic Chinese/Japanese input device for a machine translation complex. A specific scanning technique to digitize Chinese/Japanese ideographs is recommended as a result of the study. Results of the study include specification of the resolution necessary to successfully digitize…

  7. Chinese/Japanese Input Feasibility Study. Final Technical Report.

    ERIC Educational Resources Information Center

    Desautels, John E.; And Others

    A study was conducted to determine the feasibility of developing an automatic Chinese/Japanese input device for a machine translation complex. A specific scanning technique to digitize Chinese/Japanese ideographs is recommended as a result of the study. Results of the study include specification of the resolution necessary to successfully digitize…

  8. 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),…

  9. 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.

  10. 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.

  11. Structural stability of characteristic interface for NiTi/Nb Nanowire: First-Principle study

    NASA Astrophysics Data System (ADS)

    Li, G. F.; Zheng, H. Z.; Shu, X. Y.; Peng, P.

    2016-01-01

    Compared with some other conventional interface models, the interface of NiTi(211)/Nb(220) in NiTiNb metal nanocomposite had been simulated and analyzed carefully. Results show that only several interface models, i.e., NiTi(100)/Nb(100)(Ni⃡Nb), NiTi(110)/Nb(110) and NiTi(211)/Nb(220), can be formed accordingly with their negative formation enthalpy. Therein the cohesive energy Δ E and Griffith rupture work W of NiTi(211)/Nb(220) interface model are the lowest among them. Density of states shows that there exists only one electronic bonding peak for NiTi(211)/Nb(220) interface model at -2.5 eV. Electron density difference of NiTi(211)/ Nb(220) shows that the Nb-Nb, Nb-Ti and Nb-Ni bonding characters seem like so peaceful as a fabric twisting every atom, which is different from conventional metallic bonding performance. Such appearance can be deduced that the metallic bonding between Nb-Nb, Nb-Ti and Nb-Ni in NiTi(211)/Nb(220) may be affected by its nanostructure called nanometer size effect. Thus, our findings open an avenue for detailed and comprehensive studies of nanocomposite.

  12. 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.

  13. 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.

  14. Four Studies on Attribution of Ability. Technical Report Number 281.

    ERIC Educational Resources Information Center

    Feldman, Robert S.; Allen, Vernon L.

    The four studies in this report consider the attribution of ability in the relationship of tutor to tutee among elementary level students. In each of the studies, the tutee displayed, or was represented as displaying, one of four learning sequences: success-success, failure-failure, failure-success, or success-failure. The results of the first…

  15. Personality Study of Hawaii Japanese Nonagenarians: Preliminary Findings. Technical Report.

    ERIC Educational Resources Information Center

    Izutsu, Satoru; Rose, Charles L.

    As part of a larger study of the demographics, family, household, health, diet, activity, functioning, and mental ability of older Japanese people living in Hawaii which will be compared to similar studies conducted in Japan, personality data were obtained from 101 noninstitutionalized Japanese with an average age of 92 years, residing in Hawaii.…

  16. Personality Study of Hawaii Japanese Nonagenarians: Preliminary Findings. Technical Report.

    ERIC Educational Resources Information Center

    Izutsu, Satoru; Rose, Charles L.

    As part of a larger study of the demographics, family, household, health, diet, activity, functioning, and mental ability of older Japanese people living in Hawaii which will be compared to similar studies conducted in Japan, personality data were obtained from 101 noninstitutionalized Japanese with an average age of 92 years, residing in Hawaii.…

  17. Technical design aspects of Feasibility Study-II

    SciTech Connect

    Zisman, Michael S.

    2001-08-15

    Feasibility Study-II examined a high-performance Neutrino Factory providing 1 x 10{sup 20} neutrinos per year aimed at a long-baseline detector. The Study was sponsored jointly by BNL and the Neutrino Factory and Muon Collider Collaboration ration (MC) and is based on a 1 MW proton driver operating at 24 GeV, i.e., an upgraded version of the AGS accelerator. Compared with the earlier FNAL-sponsored study (Feasibility Study-I), there is a sixfold improvement in performance. Here we describe details of the implementation of Study-II concepts and discuss their efficacy. Alternative approaches that will be pursued in follow-on R and D activities are also described briefly.

  18. In-Situ TEM Study of Interface Sliding and Migration in an Ultrafine Lamellar Structure

    SciTech Connect

    Hsiung, L M

    2005-12-06

    The instability of interfaces in an ultrafine TiAl-({gamma})/Ti{sub 3}Al-({alpha}{sub 2}) lamellar structure by straining at room temperature has been investigated using in-situ straining techniques performed in a transmission electron microscope. The purpose of this study is to obtain experimental evidence to support the creep mechanisms based upon the interface sliding in association with a cooperative movement of interfacial dislocations previously proposed to interpret the nearly linear creep behavior observed from ultrafine lamellar TiAl alloys. The results have revealed that both the sliding and migration of lamellar interfaces can take place simultaneously as a result of the cooperative movement of interfacial dislocations.

  19. Studies of molecular adsorbates at interfaces by optical second-harmonic generation. [p-nitrobenzoic acid

    SciTech Connect

    Tom, H.W.K.; Heinz, T.F.; Shen, Y.R.

    1982-12-01

    Optical second-harmonic generation (SHG) is surface-specific and has the sensitivity to detect submonolayers of molecules. It can be applied to study molecular adsorbates at the interface between any two centrosymmetric media. This has been demonstrated by using dye and p-nitrobenzoic acid (PNBA) molecules adsorbed on smooth fused quartz substrates as examples. With resonant SHG, the S/sub 0/ A..-->.. S/sub 2/ transition of the adsorbed dye molecules was measured. From the polarization dependence of the SHG, the orientation of PNBA at both the air/quartz and the ethanol/quartz interfaces was deduced. By varying the concentration of PNBA in ethanol, an adsorption isotherm for PNBA at the ethanol/quartz interfaces was also obtained.

  20. 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.

  1. Thermal annealing studies of GeTe-Sb2Te3 alloys with multiple interfaces

    NASA Astrophysics Data System (ADS)

    Bragaglia, Valeria; Mio, Antonio M.; Calarco, Raffaella

    2017-08-01

    A high degree of vacancy ordering is obtained by annealing amorphous GeTe-Sb2Te3 (GST) alloys deposited on a crystalline substrate, which acts as a template for the crystallization. Under annealing the material evolves from amorphous to disordered rocksalt, to ordered rocksalt with vacancies arranged into (111) oriented layers, and finally converts into the stable trigonal phase. The role of the interface in respect to the formation of an ordered crystalline phase is studied by comparing the transformation stages of crystalline GST with and without a capping layer. The capping layer offers another crystallization interface, which harms the overall crystalline quality.

  2. 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.

  3. Molecular Mobility of the Interface in a Model Composite: A NMR Study

    DTIC Science & Technology

    1992-07-15

    liquid recovered. This product was analyzed without separation by 1H and 13C NMR to be 2-(N’-butylamino)-N-methylmaleimide. The reaction in acetone...TITLE AND SUBTITLE 5. FUNDING NUMBERS Molecular Mbility of the Interface in a Model Composite: A NMR Study N00014-91-J-1274 6. AUTHOR(S) Joan E. Gamblgi...Maximum 200 worus) The interface of a model polymer composite has been probed using solid-state NMR techniques. The adsorption of aminoalkylsilane

  4. A new JAVA interface implementation of THESIAS: testing haplotype effects in association studies.

    PubMed

    Tregouet, D A; Garelle, V

    2007-04-15

    THESIAS (Testing Haplotype EffectS In Association Studies) is a popular software for carrying haplotype association analysis in unrelated individuals. In addition to the command line interface, a graphical JAVA interface is now proposed allowing one to run THESIAS in a user-friendly manner. Besides, new functionalities have been added to THESIAS including the possibility to analyze polychotomous phenotype and X-linked polymorphisms. The software package including documentation and example data files is freely available at http://genecanvas.ecgene.net. The source codes are also available upon request.

  5. Layered interfaces between immiscible liquids studied by density-functional theory and molecular-dynamics simulations

    NASA Astrophysics Data System (ADS)

    Geysermans, P.; Elyeznasni, N.; Russier, V.

    2005-11-01

    We present a study of the structure in the interface between two immiscible liquids by density-functional theory and molecular-dynamics calculations. The liquids are modeled by Lennard-Jones potentials, which achieve immiscibility by supressing the attractive interaction between unlike particles. The density profiles of the liquids display oscillations only in a limited part of the simple liquid-phase diagram (ρ,T). When approaching the liquid-vapor coexistence, a significant depletion appears while the layering behavior of the density profile vanishes. By analogy with the liquid-vapor interface and the analysis of the adsorption this behavior is suggested to be strongly related to the drying transition.

  6. Summer Leadership Study. Part 2. Technical Reports 4-6

    DTIC Science & Technology

    1979-01-01

    travel somewhat different paths to effectiveness. Before one begins work on elaborating separate models of leader effectiveness for male and female...that communication plays in the rela. tionship between leaders and followers. For the present study, we followed the model presented by Katz and Kahn...female behavior (see also the studies of OGr en and his associates- in their investigations of the Vertical Dyad Linkage Model . Cashman, Dansereau

  7. Summer Leadership Study. Part 1. Technical Reports 1-3

    DTIC Science & Technology

    1979-01-01

    elaborating separate models of leader effectiveness for male and female styles of leadership, however, the results of the present study must be verified...present study, we followed the model presented by Katz and Kahn (1978) to conceptualize the nature of upward and downward flow of communication. The...the Vertical Dyad Linkage Model : Cashman, Dansereau, Graen and Haga, 1976; Graen, 1976). Kanter suggests that women are more often found in low power

  8. Molecular structure and dynamics of water at the water-air interface studied with surface-specific vibrational spectroscopy.

    PubMed

    Bonn, Mischa; Nagata, Yuki; Backus, Ellen H G

    2015-05-04

    Water interfaces provide the platform for many important biological, chemical, and physical processes. The water-air interface is the most common and simple aqueous interface and serves as a model system for water at a hydrophobic surface. Unveiling the microscopic (<1 nm) structure and dynamics of interfacial water at the water-vapor interface is essential for understanding the processes occurring on the water surface. At the water interface the network of very strong intermolecular interactions, hydrogen-bonds, is interrupted and the density of water is reduced. A central question regarding water at interfaces is the extent to which the structure and dynamics of water molecules are influenced by the interruption of the hydrogen-bonded network and thus differ from those of bulk water. Herein, we discuss recent advances in the study of interfacial water at the water-air interface using laser-based surface-specific vibrational spectroscopy.

  9. A phenomenographic study of the ability to address complex socio-technical systems via variation theory

    NASA Astrophysics Data System (ADS)

    Mendoza Garcia, John A.

    Sometimes engineers fail when addressing the inherent complexity of socio-technical systems because they lack the ability to address the complexity of socio-technical systems. Teaching undergraduate engineering students how to address complex socio-technical systems, has been an educational endeavor at different levels ranging from kindergarten to post-graduate education. The literature presents different pedagogical strategies and content to reach this goal. However, there are no existing empirically-based assessments guided by a learning theory. This may be because at the same time explanations of how the skill is developed are scarce. My study bridges this gap, and I propose a developmental path for the ability to address the complex socio-technical systems via Variation Theory, and according to the conceptual framework provided by Variation Theory, my research question was "What are the various ways in which engineers address complex socio-technical systems?" I chose the research approach of phenomenography to answer my research question. I also chose to use a blended approach, Marton's approach for finding the dimensions of variation, and the developmental approach (Australian) for finding a hierarchical relationship between the dimensions. Accordingly, I recruited 25 participants with different levels of experience with addressing complex socio-technical systems and asked them all to address the same two tasks: A design of a system for a county, and a case study in a manufacturing firm. My outcome space is a nona-dimensional (nine) developmental path for the ability to address the complexity in socio-technical systems, and I propose 9 different ways of experiencing the complexity of a socio-technical system. The findings of this study suggest that the critical aspects that are needed to address the complexity of socio-technical systems are: being aware of the use of models, the ecosystem around, start recognizing different boundaries, being aware of time as a

  10. Exploring the Technical Expression of Academic Knowledge: The Science-in-CTE Pilot Study

    ERIC Educational Resources Information Center

    Pearson, Donna; Young, R. Brent; Richardson, George B.

    2013-01-01

    The Science-in-CTE pilot study tested a curriculum integration model that enhanced the science that oc-curs in CTE curricula. The study replicated the National Research Center for Career and Technical Ed-ucation's (NRCCTE) Math-in-CTE experimental research design (Stone, Alfeld, & Pearson, 2008) with applied science in secondary agricultural…

  11. Exploring Technical Vocational Education and Training Systems in Emerging Markets. A Case Study on Ghana

    ERIC Educational Resources Information Center

    Arthur-Mensah, Nana; Alagaraja, Meera

    2013-01-01

    Purpose: The purpose of this study was to explore trends and changes in technical vocational education and training (TVET) in emerging economies as a national human resource development (NHRD) approach and its practical applications using Ghana as an example. Design/methodology/approach: A case study approach was used to develop an in-depth…

  12. Construction of a Digital Video Library: A Socio-Technical Pilot Study on College Students' Attitudes

    ERIC Educational Resources Information Center

    Chen, Hsin-Liang; Choi, Gilok

    2005-01-01

    This study investigates socio-technical aspects of digital video libraries based on college students' learning experiences and perspectives. Forty-one students in biology classes were studied through a survey and individual interviews. Findings are presented by the students' knowledge of computer technology, experiences with AV materials, and…

  13. Exploring Technical Vocational Education and Training Systems in Emerging Markets. A Case Study on Ghana

    ERIC Educational Resources Information Center

    Arthur-Mensah, Nana; Alagaraja, Meera

    2013-01-01

    Purpose: The purpose of this study was to explore trends and changes in technical vocational education and training (TVET) in emerging economies as a national human resource development (NHRD) approach and its practical applications using Ghana as an example. Design/methodology/approach: A case study approach was used to develop an in-depth…

  14. 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.…

  15. The Standard Progressive Matrices: A Pilot Study in a Nigerian Technical College

    ERIC Educational Resources Information Center

    McCarthy, Maureen

    1974-01-01

    The purpose of the study reported was to introduce some basic principles of guidance and counseling into the Technical College at Ife, West Africa. Results indicate that the Standard Progressive Matrices test could help to select students suited for study centering around the building trades. (Author/PG)

  16. The Standard Progressive Matrices: A Pilot Study in a Nigerian Technical College

    ERIC Educational Resources Information Center

    McCarthy, Maureen

    1974-01-01

    The purpose of the study reported was to introduce some basic principles of guidance and counseling into the Technical College at Ife, West Africa. Results indicate that the Standard Progressive Matrices test could help to select students suited for study centering around the building trades. (Author/PG)

  17. Construction of a Digital Video Library: A Socio-Technical Pilot Study on College Students' Attitudes

    ERIC Educational Resources Information Center

    Chen, Hsin-Liang; Choi, Gilok

    2005-01-01

    This study investigates socio-technical aspects of digital video libraries based on college students' learning experiences and perspectives. Forty-one students in biology classes were studied through a survey and individual interviews. Findings are presented by the students' knowledge of computer technology, experiences with AV materials, and…

  18. 41 CFR 60-3.14 - Technical standards for validity studies.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... specific validation strategy used. B. Technical standards for criterion-related validity studies—(1...) Appropriateness of construct validity studies. Construct validity is a more complex strategy than either criterion... validity studies. 60-3.14 Section 60-3.14 Public Contracts and Property Management Other Provisions...

  19. 41 CFR 60-3.14 - Technical standards for validity studies.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... specific validation strategy used. B. Technical standards for criterion-related validity studies—(1...) Appropriateness of construct validity studies. Construct validity is a more complex strategy than either criterion... validity studies. 60-3.14 Section 60-3.14 Public Contracts and Property Management Other Provisions...

  20. 41 CFR 60-3.14 - Technical standards for validity studies.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... specific validation strategy used. B. Technical standards for criterion-related validity studies—(1...) Appropriateness of construct validity studies. Construct validity is a more complex strategy than either criterion... validity studies. 60-3.14 Section 60-3.14 Public Contracts and Property Management Other Provisions...

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

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... specific validation strategy used. B. Technical standards for criterion-related validity studies—(1...) Appropriateness of construct validity studies. Construct validity is a more complex strategy than either criterion... validity studies. 60-3.14 Section 60-3.14 Public Contracts and Property Management Other Provisions...

  2. 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…

  3. 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

  4. 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.

  5. Photovoltaic applications definition and photovoltaic system definition study in the agricultural sector. Volume II. Technical results

    SciTech Connect

    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 have been 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. (WHK)

  6. Expanding Student International Awareness Through Short-Term Study Abroad Courses With Substantial Engineering Technical Content

    NASA Astrophysics Data System (ADS)

    Jacobitz, Frank; Schubert, Thomas

    2012-11-01

    The efficacy of Compact International Experience (CIE) courses is assessed in this study. These courses were developed with the aim to raise student international awareness while retaining substantial engineering technical content. The courses were motivated by a strong student desire for engineering international studies as well as a drive by the home institution for internationalization of the curriculum. The experiences gained from delivering two distinct three-semester-unit engineering elective courses in three-week time frames in France and Australia are discussed. While the two courses, Topics in Fluid Mechanics and Advanced Electronic Circuit Design, focused on their technical content, the desire for student understanding of the cultural environment and the impact of engineering solutions from a global and societal viewpoint were strong driving factors for each. Assessment validates the hypothesis that CIE courses can successfully deliver substantial engineering technical content while providing an enriching international experience to students.

  7. A pilot study comparing mouse and mouse-emulating interface devices for graphic input.

    PubMed

    Kanny, E M; Anson, D K

    1991-01-01

    Adaptive interface devices make it possible for individuals with physical disabilities to use microcomputers and thus perform many tasks that they would otherwise be unable to accomplish. Special equipment is available that purports to allow functional access to the computer for users with disabilities. As technology moves from purely keyboard applications to include graphic input, it will be necessary for assistive interface devices to support graphics as well as text entry. Headpointing systems that emulate the mouse in combination with on-screen keyboards are of particular interest to persons with severe physical impairment such as high level quadriplegia. Two such systems currently on the market are the HeadMaster and the Free Wheel. The authors have conducted a pilot study comparing graphic input speed using the mouse and two headpointing interface systems on the Macintosh computer. The study used a single subject design with six able-bodied subjects, to establish a baseline for comparison with persons with severe disabilities. Results of these preliminary data indicated that the HeadMaster was nearly as effective as the mouse and that it was superior to the Free Wheel for graphics input. This pilot study, however, demonstrated several experimental design problems that need to be addressed to make the study more robust. It also demonstrated the need to include the evaluation of text input so that the effectiveness of the interface devices with text and graphic input could be compared.

  8. Orbital operations study. Volume 2: Interfacing activities analysis. Part 4: Support operations activity group

    NASA Technical Reports Server (NTRS)

    Steinwachs, W. L.; Patrick, J. W.; Galvin, D. M.; Turkel, S. H.

    1972-01-01

    The findings of the support operations activity group of the orbital operations study are presented. Element interfaces, alternate approaches, design concepts, operational procedures, functional requirements, design influences, and approach selection are presented. The following areas are considered: (1) crew transfer, (2) cargo transfer, (3) propellant transfer, (4) attached element operations, and (5) attached element transport.

  9. Orbital operations study. Volume 2: Interfacing activities analysis. Part 2: Structural and mechanical group

    NASA Technical Reports Server (NTRS)

    Mattson, H. L.; Gianformaggio, A.; Anderson, N. R.

    1972-01-01

    The activities of the structural and mechanical activity group of the orbital operations study project are discussed. Element interfaces, alternate approaches, design concepts, operational procedures, functional requirements, design influences, and approach selection are presented. The following areas are considered: (1) mating, (2) orbital assembly, (3) separation, EOS payload deployment, and EOS payload retraction.

  10. Orbital operation study. Volume 2: Interfacing activities analysis. Part 1: Introduction and summary

    NASA Technical Reports Server (NTRS)

    Anderson, N. R.

    1972-01-01

    The summary of the interfacing activity analyses for the orbital operations study is presented. The significant analyses are grouped into categories as follows: (1) structural and mechanical activity, (2) data management, and (3) support operations. Specific subjects concerning payload deployment, communications, rendezvous, and stationkeeping are discussed.

  11. Environmental DNA calibration study interim technical review report December 2014

    USGS Publications Warehouse

    Baerwaldt, Kelly; Bartron, Meredith; Schilling, Kurt; Lee, Debbie; Russo, Edmond; Estes, Trudy; Fischer, Richard; Fleming, Beth; Guilfoyle, Michael P.; Killgore, Jack; Lance, Richard; Perkins, Edward; Schultz, Martin; Smith, David; Amberg, Jon J.; Chapman, Duane C.; Gaikowski, Mark P.; Klymus, Katy E.; Richter, Cathy

    2015-01-01

    The Environmental DNA Calibration Study (ECALS) is a multi-year study to improve the understanding and interpretation of the detection of Asian carp DNA in environmental samples (eDNA) used in early detection monitoring. eDNA surveillance programs seek to detect the presence of genetic material (DNA in cells sloughed off in slime, feces, urine, etc.) extracted from water samples; the detection of genetic material is linked to the possible presence of Asian carp. The study involves collaboration between the U.S. Army Corps of Engineers, the U.S. Geological Survey, and the U.S. Fish and Wildlife Service. ECALS addresses three major Action Items from the Asian Carp Regional Coordinating Committee (ACRCC) Asian Carp Control Strategy Framework, of which results to date are presented below. Initial ECALS efforts focused on eDNA vectors whereas marker development and calibration experiments received greater attention in 2013.

  12. Local Assessment System Implementation Study (2003-2004): Technical Report.

    ERIC Educational Resources Information Center

    Maine Department of Education, 2004

    2004-01-01

    This document includes the results of Maine's 2003-2004 study examining actions taken by 18 school districts in response to the challenges of developing a Local Assessment System (LAS) using the principles and criteria set forth in the "LAS Guide" distributed to school districts in June, 2003. The report is organized into three parts:…

  13. Final Technical Report: Renewable Energy Feasibility Study and Resources Assessment

    SciTech Connect

    Rivero, Mariah

    2016-02-28

    In March 2011, the U.S. Department of Energy (DOE) awarded White Pine County, Nevada, a grant to assess the feasibility of renewable resource-related economic development activities in the area. The grant project included a public outreach and training component and was to include a demonstration project; however, the demonstration project was not completed due to lack of identification of an entity willing to locate a project in White Pine County. White Pine County completed the assessment of renewable resources and a feasibility study on the potential for a renewable energy-focused economic sector within the County. The feasibility study concluded "all resources studied were present and in sufficient quantity and quality to warrant consideration for development" and there were varying degrees of potential economic impact based on the resource type and project size. The feasibility study and its components were to be used as tools to attract potential developers and other business ventures to the local market. White Pine County also marketed the County’s resources to the renewable energy business community in an effort to develop contracts for demonstration projects. The County also worked to develop partnerships with local educational institutions, including the White Pine County School District, conducted outreach and training for the local community.

  14. TECHNICAL REPORT: Studies of ``Kapustinsky's'' light pulser timing characteristics

    NASA Astrophysics Data System (ADS)

    Lubsandorzhiev, B. K.; Vyatchin, Y. E.

    2006-06-01

    We present the results of studies of a nanosecond light pulser built following an original design of J.S. Kapustinsky et al and using bright InGaN/GaN ultraviolet and blue LEDs produced by Nichia Chemical. It is shown how timing characteristics of the pulser depend on the type of LED and the value of power supply voltage.

  15. Relation of Study Factors to Performance in Navy Technical Schools

    DTIC Science & Technology

    1992-08-01

    factors courses are effective In helping students improve their academic performance (Brozo, Schmelzer , & Thurber, 1982). High-risk and disadvantaged...students’ study skills. Journal of Reading, 31, 361-364. Brozo, W. G., Schmelzer , R. V., & Thurber, R. G. (1982). In the learning center: Differential

  16. 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.

  17. 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.

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

    PubMed

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

    2014-10-01

    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. 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). 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. 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. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  19. 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

  20. COMPARATIVE EFFECTIVENESS OF AN ADJUSTABLE TRANSFEMORAL PROSTHETIC INTERFACE ACCOMMODATING VOLUME FLUCTUATION: CASE STUDY

    PubMed Central

    Kahle, Jason T.; Klenow, Tyler D.; Highsmith, M. Jason

    2016-01-01

    The socket-limb interface is vital for functionality and provides stability and mobility for the amputee. Volume fluctuation can lead to compromised fit and function. Current socket technology does not accommodate for volume fluctuation. An adjustable interface may improve function and comfort by filling this technology gap. The purpose of this study was to compare the effectiveness of the standard of care (SOC) ischial ramus containment to an adjustable transfemoral prosthetic interface socket in the accommodation of volume fluctuation. A prospective experimental case study using repeated measures of subjective and performance outcome measures between socket conditions was employed. In the baseline volume condition, the adjustable socket improved subjective and performance measures 19% to 37% over SOC, whereas the two-minute walk test demonstrated equivalence. In the volume loss condition, the adjustable socket improved all subjective and performance measures 22% to 93%. All aggregated data improved 16% to 50% compared with the SOC. In simulated volume gain, the SOC socket failed, while the subject was able to complete the protocol using the adjustable socket. In this case study, the SOC socket was inferior to the comparative adjustable transfemoral amputation interface in subjective and performance outcomes. There is a lack of clinical trials and evidence comparing socket functional outcomes related to volume fluctuation. PMID:28066526

  1. COMPARATIVE EFFECTIVENESS OF AN ADJUSTABLE TRANSFEMORAL PROSTHETIC INTERFACE ACCOMMODATING VOLUME FLUCTUATION: CASE STUDY.

    PubMed

    Kahle, Jason T; Klenow, Tyler D; Highsmith, M Jason

    2016-09-01

    The socket-limb interface is vital for functionality and provides stability and mobility for the amputee. Volume fluctuation can lead to compromised fit and function. Current socket technology does not accommodate for volume fluctuation. An adjustable interface may improve function and comfort by filling this technology gap. The purpose of this study was to compare the effectiveness of the standard of care (SOC) ischial ramus containment to an adjustable transfemoral prosthetic interface socket in the accommodation of volume fluctuation. A prospective experimental case study using repeated measures of subjective and performance outcome measures between socket conditions was employed. In the baseline volume condition, the adjustable socket improved subjective and performance measures 19% to 37% over SOC, whereas the two-minute walk test demonstrated equivalence. In the volume loss condition, the adjustable socket improved all subjective and performance measures 22% to 93%. All aggregated data improved 16% to 50% compared with the SOC. In simulated volume gain, the SOC socket failed, while the subject was able to complete the protocol using the adjustable socket. In this case study, the SOC socket was inferior to the comparative adjustable transfemoral amputation interface in subjective and performance outcomes. There is a lack of clinical trials and evidence comparing socket functional outcomes related to volume fluctuation.

  2. Angle-resolved photoemission spectroscopy studies of metallic surface and interface states of oxide insulators.

    PubMed

    Plumb, Nicholas C; Radović, Milan

    2017-09-29

    Over the last decade, conducting states embedded in insulating transition metal oxides (TMOs) have served as gateways to discovering and probing surprising phenomena that can emerge in complex oxides, while also opening opportunities for engineering advanced devices. These states are commonly realized at thin film interfaces, such as the well-known case of LaAlO3 (LAO) grown on SrTiO3 (STO). In recent years, the use of angle-resolved photoemission spectroscopy (ARPES) to investigate the k-space electronic structure of such materials led to the discovery that metallic states can also be formed on the bare surfaces of certain TMOs. In this topical review, we report on recent studies of low-dimensional metallic states confined at insulating oxide surfaces and interfaces as seen from the perspective of ARPES, which provides a direct view of the occupied band structure. While offering a fairly broad survey of progress in the field, we draw particular attention to STO, whose surface is so far the best-studied, and whose electronic structure is probably of the most immediate interest, given the ubiquitous use of STO substrates as the basis for conducting oxide interfaces. The ARPES studies provide crucial insights into the electronic band structure, orbital character, dimensionality/confinement, spin structure, and collective excitations in STO surfaces and related oxide surface/interface systems. The obtained knowledge increases our understanding of these complex materials and gives new perspectives on how to manipulate their properties.

  3. Design and Technical Study of Neutrino Detector Spacecraft

    NASA Technical Reports Server (NTRS)

    Solomey, Niclolas

    2017-01-01

    A neutrino detector is proposed to be developed for use on a space probe in close orbit of the Sun. The detector will also be protected from radiation by a tungsten shield Sun shade, active veto array and passive cosmic shielding. With the intensity of solar neutrinos substantially greater in a close solar orbit than on the Earth only a small 250 kg detector is needed. It is expected that this detector and space probe studying the core of the Sun, its nuclear furnace and particle physics basic properties will bring new knowledge beyond what is currently possible for Earth bound solar neutrino detectors.

  4. Segregation of ions at the interface: molecular dynamics studies of the bulk and liquid-vapor interface structure of equimolar binary mixtures of ionic liquids.

    PubMed

    Palchowdhury, Sourav; Bhargava, B L

    2015-08-14

    The structures of three different equimolar binary ionic liquid mixtures and their liquid-vapor interface have been studied using atomistic molecular dynamics simulations. Two of these binary mixtures were composed of a common cation 1-n-butyl-3-methylimidazolium and varying anions (chloride and hexafluorophosphate in one of the mixtures and chloride and trifluoromethanesulfonate in the other) and the third binary mixture was composed of a common anion, trifluoromethanesulfonate and two imidazolium cations with ethyl and octyl side chains. Binary mixtures with common cations are found to be homogeneous. The anions are preferentially located near the ring hydrogen atoms due to H-bonding interactions. Segregation of ions is observed at the interface with an enrichment of the liquid-vapor interface layer by longer alkyl chains and bigger anions with a distributed charge. The surface composition is drastically different from that of the bulk composition, with the longer alkyl tail groups and bigger anions populating the outermost layer of the interface. The longer alkyl chains of the cations and trifluoromethanesulfonate anions with a smaller charge density show orientational ordering at the liquid-vapor interface.

  5. 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.

  6. 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.

  7. Study of Dose Perturbation at Bone-Tissue Interfaces in Megavoltage Photon Beam Therapy.

    NASA Astrophysics Data System (ADS)

    Das, Indra Jeet

    Dose perturbations during photon beam irradiation occur at interfaces between two dissimilar media due to the loss of electronic equilibrium. The human body contains many different types of interfaces between soft tissue and other media such as, air cavities, lungs, bones, and high atomic number (Z) materials. The dose to critical organs in the vicinity of high Z interfaces, is what leads to this project. This work describes the dose perturbation at high Z (from bone to lead) interfaces with soft tissue for clinically used megavoltage photon beams in the range of CO-60 gamma rays to 24 MV X-rays. It is divided into three main sections: (1) the dose outside the inhomogeneity in the direction of backscatter, (2) the dose inside the inhomogeneity, and (3) the dose on the photon transmission side of the inhomogeneity. Using different types of parallel plate ion chambers, TLD (powder and chip), and film as dosimeters, the dose perturbation is studied as a function of photon energy, thickness, width, and depth of inhomogeneity, distance from the interface and radiation field size. The concept of Bragg-Gray cavity theory is applied and verified for dose determination inside the inhomogeneity. A significant dose enhancement has been observed on the backscatter side for all photon energies. It is strongly dependent on the atomic number of the inhomogeneity and less dependent on the photon energy, thickness, depth, width, and field size. In the forward direction, a dose reduction occurs at the interface at beam energies lower than 10 MV, whereas a dose enhancement occurs for higher photon energies. The interface effect persists up to a few millimeters on the backscatter side but a distance equivalent to the secondary electron range for the particular photon beams in the forward direction. The dose perturbation is explained on the basis of production and transport of secondary electrons. Empirical functions are derived from the experimental data to predict the dose

  8. 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.

  9. First-principles study of alloy formation at Fe/GaAs interfaces

    NASA Astrophysics Data System (ADS)

    Zutic, Igor

    2005-03-01

    The combination of the high Curie temperature of Fe, high-quality epitaxial growth of Fe on GaAs, and demonstrated high-efficiency spin injection in GaAs, together make Fe/GaAs heterojunctions very attractive candidates for room-temperature spintronic applications. However, little is known about the structure of Fe/GaAs interfaces, and there is a range of conflicting experimental results describing them---including findings of magnetically dead layers [1], an intermediate FeGaAs phase [2], and bulk-like magnetic moments at the interface [3]. Motivated by these findings, we use density-functional theory to study the structural and magnetic properties of interfaces involving possible alloyed phases occurring between Fe and GaAs. From the calculation of interface formation energies we report results on the stability of various structural and magnetic configurations, and provide microscopic parameters which may be used in studies of spin transport to assess the device potential of these heterostructures. [1] J. J. Krebs, B. T. Jonker, and G. A. Prinz, J. Appl. Phys. 61, 2596 (1987). [2] J. Deputier, R. Guerin, B. Lepine, A. Guivarc'h, and G. Jezequel, J. Alloys Comp. 262, 416 (1997). [3] J. S. Claydon, Y. B. Hu, M. Tselepi, J. A. C. Bland, and G. van der Laan, Phys. Rev. Lett. 93, 037206 (2004).

  10. 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.

  11. 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.

  12. Density functional theory based study of chlorine doped WS{sub 2}-metal interface

    SciTech Connect

    Chanana, Anuja; Mahapatra, Santanu

    2016-03-07

    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 WS{sub 2} 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 WS{sub 2} 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 WS{sub 2}.

  13. 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.

  14. 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.

  15. 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…

  16. A Study of the Admissions Criteria of Connecticut's Regional Vocational Technical Schools. Phase III. Final Report.

    ERIC Educational Resources Information Center

    Whinfield, R.W.

    A 4-year study was conducted to determine whether the selection criteria for entrance into the 17 Regional Vocational Technical Schools of Connecticut were fair to all applicants of various races and both sexes and predictive of students' success in school programs. The evaluation process consisted of reviewing and applying students' grades and…

  17. 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…

  18. A 2015 Status Study of Career and Technical Education Programs in the United States

    ERIC Educational Resources Information Center

    Fletcher, Edward C., Jr.; Gordon, Howard R. D.; Asunda, Paul; Zirkle, Chris

    2015-01-01

    With the decline of Career and Technical Education (CTE) programs across the nation, there has been an interest in examining the status of these programs, particularly given the increased demand for CTE K-12 teachers. It has been 15 years since Bruening et al. (2001) conducted a similar national investigation. In this descriptive study, we…

  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. 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…

  1. Tactics for Building Images of Audience in Organizational Contexts: An Ethnographic Study of Technical Communicators.

    ERIC Educational Resources Information Center

    Hovde, Marjorie Rush

    2000-01-01

    Examines computer documentation writers' tactics for conceiving of their audiences. Describes and evaluates technical communicators' tactics for understanding audiences, constrained and supported by their organizations based on two ethnographic case studies and insights from activity theory. Discusses the advantages and limitations of each tactic,…

  2. 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…

  3. 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…

  4. 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…

  5. A Study on Technical High School Teachers' Views Concerning Corporal Punishment

    ERIC Educational Resources Information Center

    Tas, Said

    2016-01-01

    Corporal punishment is defined as inflicting pain on body of someone who presents undesired behavior or does not present expected behavior. In the developed world, experiencing information society, corporal punishment is still in the agenda in educational system in Turkey. In this study, it was aimed to determine technical high school teachers'…

  6. 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…

  7. 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.…

  8. 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…

  9. 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,…

  10. Study of Residential Vocational Technical Center(s) in Maryland: Part II. Final Report.

    ERIC Educational Resources Information Center

    McManis Associates, Inc., Washington, DC.

    Part 1 of the project aimed at determining unmet vocational-technical education needs in the State of Maryland which might be met through residential education; Part 2 was designed to study the possible alternatives for meeting the needs discovered and to make recommendations regarding how these could best be met. A summary of Part 1 of the…

  11. 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…

  12. 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,…

  13. 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…

  14. Technical Communication, Literary Theory, and English Studies: Stasis, Change, and the Problem of Meaning.

    ERIC Educational Resources Information Center

    Tebeaux, Elizabeth

    1991-01-01

    Maintains that technical communication curricula occupy valid theoretical positions within English studies. Advocates curricula which emphasize the connections between reading and writing, the historical-cultural contexts underlying communication, and a new rhetoric for technology-based communications and readers with global language skills. (SR)

  15. 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…

  16. 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…

  17. 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…

  18. Technical feasibility of integrating 7 T anatomical MRI in image-guided radiotherapy of glioblastoma: a preparatory study.

    PubMed

    Compter, Inge; Peerlings, Jurgen; Eekers, Daniëlle B P; Postma, Alida A; Ivanov, Dimo; Wiggins, Christopher J; Kubben, Pieter; Küsters, Benno; Wesseling, Pieter; Ackermans, Linda; Schijns, Olaf E M G; Lambin, Philippe; Hoffmann, Aswin L

    2016-06-01

    The use of 7 Tesla (T) magnetic resonance imaging (MRI) has recently shown great potential for high-resolution soft-tissue neuroimaging and visualization of microvascularization in glioblastoma (GBM). We have designed a clinical trial to explore the value of 7 T MRI in radiation treatment of GBM. For this aim we performed a preparatory study to investigate the technical feasibility of incorporating 7 T MR images into the neurosurgical navigation and radiotherapy treatment planning (RTP) systems via qualitative and quantitative assessment of the image quality. The MR images were acquired with a Siemens Magnetom 7 T whole-body scanner and a Nova Medical 32-channel head coil. The 7 T MRI pulse sequences included magnetization-prepared two rapid acquisition gradient echoes (MP2RAGE), T2-SPACE, SPACE-FLAIR and gradient echo sequences (GRE). A pilot study with three healthy volunteers and an anthropomorphic 3D phantom was used to assess image quality and geometrical image accuracy. The MRI scans were well tolerated by the volunteers. Susceptibility artefacts were observed in both the cortex and subcortical white matter at close proximity to air-tissue interfaces. Regional loss of signal and contrast could be minimized by the use of dielectric pads. Image transfer and processing did not degrade image quality. The system-related spatial uncertainty of geometrical distortion-corrected MP2RAGE pulse sequences was ≤2 mm. Integration of high-quality and geometrically-reliable 7 T MR images into neurosurgical navigation and RTP software is technically feasible and safe.

  19. DDC 10 Year Requirements and Planning Study. Volume II. Technical Discussion, Bibliography, and Glossary

    DTIC Science & Technology

    1976-06-12

    Technology of Information Procesoing (1978-1988) ........ .................. ... 39 2.2.3 Organizational Interface Between DDC and Other Information...Requirements and Planning Study: Expert Penal Review Report. December 31, 1975. (AUER-2325/2326-T-N5 AD-A022 303) TABLE 14 Evaluation of Technological

  20. Ab initio study of the BaTiO3/Ge interface

    NASA Astrophysics Data System (ADS)

    Dogan, Mehmet; Ismail-Beigi, Sohrab

    2017-08-01

    We present a comprehensive first-principles study of BaTiO3 ultrathin films epitaxially grown on Ge(001). We recently reported on the experimental realization of this system and analyzed the 2 ×1 structural distortions in the BTO thin film which may give rise to technologically relevant functional properties [D. P. Kumah et al., Phys. Rev. Lett. 116, 106101 (2016), 10.1103/PhysRevLett.116.106101]. In this work, we describe the structural and electronic properties of the experimentally observed interface configuration, as well as a distinct metastable interface configuration with a higher out-of-plane polarization. We show that these two distinct interface structures can be made energetically degenerate by choosing a top electrode with an appropriate work function, thus enabling, in principle, an epitaxial ferroelectric thin film oxide. We analyze the interface chemistry and electronic structure and show that in the two polarization states the bands align differently, indicating a strong ferroelectric field effect. We also show that, surprisingly, in the intrinsic limit for the semiconductor, switching the oxide polarization state can cause the dominant charge carrier to switch between electrons and holes. The coupling of ferroelectric switching in the oxide with charge carrier type modulation in the semiconductor may have novel technological applications.

  1. 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.

  2. Multi-Robot Interfaces and Operator Situational Awareness: Study of the Impact of Immersion and Prediction

    PubMed Central

    Peña-Tapia, Elena; Martín-Barrio, Andrés; Olivares-Méndez, Miguel A.

    2017-01-01

    Multi-robot missions are a challenge for operators in terms of workload and situational awareness. These operators have to receive data from the robots, extract information, understand the situation properly, make decisions, generate the adequate commands, and send them to the robots. The consequences of excessive workload and lack of awareness can vary from inefficiencies to accidents. This work focuses on the study of future operator interfaces of multi-robot systems, taking into account relevant issues such as multimodal interactions, immersive devices, predictive capabilities and adaptive displays. Specifically, four interfaces have been designed and developed: a conventional, a predictive conventional, a virtual reality and a predictive virtual reality interface. The four interfaces have been validated by the performance of twenty-four operators that supervised eight multi-robot missions of fire surveillance and extinguishing. The results of the workload and situational awareness tests show that virtual reality improves the situational awareness without increasing the workload of operators, whereas the effects of predictive components are not significant and depend on their implementation. PMID:28749407

  3. Structural changes of soy proteins at the oil-water interface studied by fluorescence spectroscopy.

    PubMed

    Keerati-u-rai, Maneephan; Miriani, Matteo; Iametti, Stefania; Bonomi, Francesco; Corredig, Milena

    2012-05-01

    Fluorescence spectroscopy was used to acquire information on the structural changes of proteins at the oil/water interface in emulsions prepared by using soy protein isolate, glycinin, and β-conglycinin rich fractions. Spectral changes occurring from differences in the exposure of tryptophan residues to the solvent were evaluated with respect to spectra of native, urea-denatured, and heat treated proteins. The fluorescence emission maxima of the emulsions showed a red shift with respect to those of native proteins, indicating that the tryptophan residues moved toward a more hydrophilic environment after adsorption at the interface. The heat-induced irreversible transitions were investigated using microcalorimetry. Fluorescence spectroscopy studies indicated that while the protein in solution underwent irreversible structural changes with heating at 75 and 95°C for 15 min, the interface-adsorbed proteins showed very little temperature-induced rearrangements. The smallest structural changes were observed in soy protein isolate, probably because of the higher extent of protein-protein interactions in this material, as compared to the β-conglycinin and to the glycinin fractions. This work brings new evidence of structural changes of soy proteins upon adsorption at the oil water interface, and provides some insights on the possible protein exchange events that may occur between adsorbed and unadsorbed proteins in the presence of oil droplets. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. In situ studies on ferroelectric BaTiO3 interface

    NASA Astrophysics Data System (ADS)

    Shin, Junsoo; Braun Nascimento, Von; Plummer, Ward; Zhang, Jiandi; Borisevich, Albina; Meunier, Vincent; Kalinin, Sergei; Baddorf, Arthur

    2012-02-01

    Ferroelectric phase stability in ferroelectric films is critically dependent on the surface and interface phenomena, especially governed by electrostatic depolarization energy. Predictions for the minimum critical film thickness for ferroelectricity have continuously decreased down to few unit cells. We have examined surface/interface atomic structures of ultrathin BaTiO3 (BTO) films grown on conductive SrRuO3 (SRO) and Nb-doped SrTiO3. The surface structure of BTO/SRO was refined using in-situ Low Energy Electron Diffraction (LEED) I-V, resulting to observation of polar distortion in ultrathin (>= 4 ML) BTO films. The in-situ Scanning Tunneling Microscopy (STM) has been performed prior and after BTO deposition on SRO. However, the unusual 2x2 reconstruction is observed for 1-2 ML BTO films and bare SRO by STM. The surface reconstruction of SRO bottom electrode is shown to affect the interface of films deposited subsequently which could be reflected in ultrathin film properties. The in-situ LEED I-V structural studies on 1-2 ML BTO interface have been performed without SRO layer, which kept ultrathin BTO films from the preclusion of reconstructed SRO films.

  5. External potential dynamic studies on the formation of interface in polydisperse polymer blends.

    PubMed

    Qi, Shuanhu; Zhang, Xinghua; Yan, Dadong

    2010-02-14

    The formation of interface from an initial sharp interface in polydisperse A/B blends is studied using the external potential dynamic method. The present model is a nonlocal coupling model as we take into account the correlation between segments in a single chain. The correlation is approximately expressed by Debye function and the diffusion dynamics are based on the Rouse chain model. The chain length distribution is described by the continuous Schulz distribution. Our numerical calculation indicates that for a wide range of the Flory-Huggins parameter the broadening of interface with respect to time obeys a power law at early time, and the power indices are the same for both monodisperse and polydisperse blends. The power index is larger than that in the local coupling model. However, there is no unified scaling form of the broadening of the interface width if only the interfacial width at equilibrium is taken into account as the characteristic length of the system, because the correlation makes an extra characteristic length in the system, and the polydispersity is related to this length.

  6. Study on user interface of pathology picture archiving and communication system.

    PubMed

    Kim, Dasueran; Kang, Peter; Yun, Jungmin; Park, Sung-Hye; Seo, Jeong-Wook; Park, Peom

    2014-01-01

    It is necessary to improve the pathology workflow. A workflow task analysis was performed using a pathology picture archiving and communication system (pathology PACS) in order to propose a user interface for the Pathology PACS considering user experience. An interface analysis of the Pathology PACS in Seoul National University Hospital and a task analysis of the pathology workflow were performed by observing recorded video. Based on obtained results, a user interface for the Pathology PACS was proposed. Hierarchical task analysis of Pathology PACS was classified into 17 tasks including 1) pre-operation, 2) text, 3) images, 4) medical record viewer, 5) screen transition, 6) pathology identification number input, 7) admission date input, 8) diagnosis doctor, 9) diagnosis code, 10) diagnosis, 11) pathology identification number check box, 12) presence or absence of images, 13) search, 14) clear, 15) Excel save, 16) search results, and 17) re-search. And frequently used menu items were identified and schematized. A user interface for the Pathology PACS considering user experience could be proposed as a preliminary step, and this study may contribute to the development of medical information systems based on user experience and usability.

  7. Deciphering β-Lactoglobulin Interactions at an Oil-Water Interface: A Molecular Dynamics Study.

    PubMed

    Zare, Davoud; McGrath, Kathryn M; Allison, Jane R

    2015-06-08

    Protein adsorption at liquid-liquid interfaces is of immense relevance to many biological processes and dairy-based functional foods. Due to experimental limitations, however, there is still a remarkable lack of understanding of the adsorption mechanism, particularly at a molecular level. In this study, atomistic molecular dynamics simulations were used to elucidate the approach and adsorption mechanism of β-lactoglobulin (β-LG) at a decane-water interface. Through multiple independent simulations starting from three representative initial orientations of β-LG relative to the decane surface the rate at which β-LG approaches the oil/water interface is found to be independent of its initial orientation, and largely stochastic in nature. While the residues that first make contact with the decane and the final orientation of β-LG upon adsorption are similar in all cases, the adsorption process is driven predominantly by structural rearrangements that preserve the secondary structure but expose hydrophobic residues to the decane surface. This detailed characterization of the adsorption of β-LG at an oil/water interface should inform the design and development of novel encapsulation and delivery systems in the food and pharmaceutical sciences.

  8. Direct Imaging and First Principles Studies of Si3N4/SiO2 Interface

    NASA Astrophysics Data System (ADS)

    Walkosz, Weronika; Klie, Robert; Ogut, Serdar; Mikijelj, Bilijana; Pennycook, Stephen; Idrobo, Juan C.

    2010-03-01

    It is well known that the composition of the integranular films (IGFs) in sintered polycrystalline silicon nitride (Si3N4) ceramics controls many of their physical and mechanical properties. A considerable effort has been made to characterize these films on the atomic scale using both experimental and theoretical methods. In this talk, we present results from a combined atomic-resolution Z-contrast and annular bright field imaging, electron energy-loss spectroscopy, as well as ab initio studies of the interface between β-Si3N4 (10-10) and SiO2 intergranular film. Our results show that O replaces N at the interface between the two materials in agreement with our theoretical calculations and that N is present in the SiO2 IGF. Moreover, they indicate the presence of atomic columns completing Si3N4 open rings, which have not been observed experimentally at the recently imaged Si3N4/rare-earth oxides interfaces, but have been predicted theoretically on bare Si3N4 surfaces. The structural and electronic variations at the Si3N4/SiO2 interface will be discussed in detail, focusing in particular on bonding characteristics.

  9. 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.

  10. Interface of graphane with copper: a van der Waals density-functional study

    NASA Astrophysics Data System (ADS)

    Buonocore, Francesco; Capasso, Andrea; Lisi, Nicola

    2014-03-01

    Various forms of hydrogenated graphene have been produced to date by several groups, while the synthesis of pure graphane has not been achieved yet. The study of the interface between graphane, in all its possible hydrogenation configurations, and catalyst metal surfaces can be pivotal to assess the feasibility of direct CVD growth methods for this material. We investigated the adhesion of graphane to a Cu(111) surface by adopting the vdW-DF2-C09 exchange-correlation functional, which is able to describe dispersion forces. The results are further compared with the PBE and the LDA exchange-correlation functionals. We calculated the most stable geometrical configurations of the slab/graphane interface and evaluated how graphane’s geometrical parameters are modified. We show that dispersion forces play an important role in the slab/graphane adhesion. Band structure calculations demonstrated that in the presence of the interaction with copper, the band gap of graphane is not only preserved, but also enlarged, and this increase can be attributed to the electronic charge accumulated at the interface. We calculated a substantial energy barrier at the interface, suggesting that CVD graphane films might act as reliable and stable insulating thin coatings, or also be used to form compound layers in conjunction with metals and semiconductors.

  11. 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.

  12. 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.

  13. Atomistic study of mixing at high Z / low Z interfaces at Warm Dense Matter Conditions

    NASA Astrophysics Data System (ADS)

    Haxhimali, Tomorr; Glosli, James; Rudd, Robert; Lawrence Livermore National Laboratory Team

    2016-10-01

    We use atomistic simulations to study different aspects of mixing occurring at an initially sharp interface of high Z and low Z plasmas in the Warm/Hot Dense Matter regime. We consider a system of Diamond (the low Z component) in contact with Ag (the high Z component), which undergoes rapid isochoric heating from room temperature up to 10 eV, rapidly changing the solids into warm dense matter at solid density. We simulate the motion of ions via the screened Coulomb potential. The electric field, the electron density and ionizations level are computed on the fly by solving Poisson equation. The spatially varying screening lengths computed from the electron cloud are included in this effective interaction; the electrons are not simulated explicitly. We compute the electric field generated at the Ag-C interface as well as the dynamics of the ions during the mixing process occurring at the plasma interface. Preliminary results indicate an anomalous transport of high Z ions (Ag) into the low Z component (C); a phenomenon that is partially related to the enhanced transport of ions due to the generated electric field. These results are in agreement with recent experimental observation on Au-diamond plasma interface. This work was performed under the auspices of the US Dept. of Energy by Lawrence Livermore National Security, LLC under Contract DE-AC52-07NA27344.

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

    PubMed

    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.

  17. 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.

  18. Adsorption of naphthalene and ozone on atmospheric air/ice interfaces coated with surfactants: a molecular simulation study.

    PubMed

    Liyana-Arachchi, Thilanga P; Valsaraj, Kalliat T; Hung, Francisco R

    2012-03-15

    The adsorption of gas-phase naphthalene and ozone molecules onto air/ice interfaces coated with different surfactant species (1-octanol, 1-hexadecanol, or 1-octanal) was investigated using classical molecular dynamics (MD) simulations. Naphthalene and ozone exhibit a strong preference to be adsorbed at the surfactant-coated air/ice interfaces, as opposed to either being dissolved into the bulk of the quasi-liquid layer (QLL) or being incorporated into the ice crystals. The QLL becomes thinner when the air/ice interface is coated with surfactant molecules. The adsorption of both naphthalene and ozone onto surfactant-coated air/ice interfaces is enhanced when compared to bare air/ice interface. Both naphthalene and ozone tend to stay dissolved in the surfactant layer and close to the QLL, rather than adsorbing on top of the surfactant molecules and close to the air region of our systems. Surfactants prefer to orient at a tilted angle with respect to the air/ice interface; the angular distribution and the most preferred angle vary depending on the hydrophilic end group, the length of the hydrophobic tail, and the surfactant concentration at the air/ice interface. Naphthalene prefers to have a flat orientation on the surfactant coated air/ice interface, except at high concentrations of 1-hexadecanol at the air/ice interface; the angular distribution of naphthalene depends on the specific surfactant and its concentration at the air/ice interface. The dynamics of naphthalene molecules at the surfactant-coated air/ice interface slow down as compared to those observed at bare air/ice interfaces. The presence of surfactants does not seem to affect the self-association of naphthalene molecules at the air/ice interface, at least for the specific surfactants and the range of concentrations considered in this study.

  19. Farmers' Training and Functional Literacy. A Pilot Evaluation Study of Functional Literacy Project in Lucknow District. Technical Report.

    ERIC Educational Resources Information Center

    Ministry of Education and Social Welfare, New Delhi (India).

    The technical report of the Pilot Evaluation Study of Functional Literacy Project in Lucknow District, Uttar Pradesh, India presents the research procedures and statistical analysis for the previously published non-technical report of the study. The main study objectives were to obtain qualitative and quantitative measurements of attainment and…

  20. Electrochemistry-mass spectrometry for mechanism study of oxygen reduction at water/oil interface

    NASA Astrophysics Data System (ADS)

    Liu, Shu-Juan; Yu, Zheng-Wei; Qiao, Liang; Liu, Bao-Hong

    2017-04-01

    Electrochemistry methods have been widely employed in the development of renewable energy, and involved in various processes, e.g. water splitting and oxygen reduction. Remarkable progress notwithstanding, there are still many challenges in further optimization of catalysts to achieve high performance. For this purpose, an in-depth understanding of reaction mechanism is needed. In this study, an electrochemistry-mass spectrometry method based on a Y-shaped dual-channel microchip as electrochemical cell and ionization device was demonstrated. Combined solutions of aqueous phase and oil phase were introduced into mass spectrometer directly when electrochemical reactions were happening to study the reduction of oxygen by decamethylferrocene or tetrathiafulvalene under the catalysis of a metal-free porphyrin, tetraphenylporphyrin, at water/1,2-dichloroethane interfaces. Monoprotonated and diprotonated tetraphenylporphyrin were detected by mass spectrometer, confirming the previously proposed mechanism of the oxygen reduction reaction. This work offers a new approach to study electrochemical reactions at liquid-liquid interface.

  1. Lattice boltzmann study on the contact angle and contact line dynamics of liquid-vapor interfaces.

    PubMed

    Zhang, Junfeng; Kwok, Daniel Y

    2004-09-14

    The moving contact line problem of liquid-vapor interfaces was studied using a mean-field free-energy lattice Boltzmann method recently proposed [Phys. Rev. E 2004, 69, 032602]. We have examined the static and dynamic interfacial behaviors by means of the bubble and capillary wave tests and found that both the Laplace equation of capillarity and the dispersion relation were satisfied. Dynamic contact angles followed the general trend of contact line velocity observed experimentally and can be described by Blake's theory. The velocity fields near the interface were also obtained and are in good agreement with fluid mechanics and molecular dynamics studies. Our simulations demonstrated that incorporating interfacial effects into the lattice Boltzmann model can be a valuable and powerful alternative in interfacial studies.

  2. 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…

  3. 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…

  4. 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.

  5. 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.

  6. 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

  7. Studies in RF power communication, SAR, and temperature elevation in wireless implantable neural interfaces.

    PubMed

    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.

  8. Role of Research, Planning and Resource Development Functions in Postsecondary Vocational Education. Report of a Study of Selected Community Colleges, Technical Colleges, and Technical Institutes.

    ERIC Educational Resources Information Center

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

    This study was conducted in Wisconsin to determine the current status of personnel within the vocational, technical and adult education (VTAE) districts responsible for research, planning, and development (RPD) activities, what activities were being performed by the districts, and the nature of involvement in the performance of these RPD…

  9. 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…

  10. Evaluating user interfaces in context: the ecological value of time-and-motion studies.

    PubMed

    Lindgaard, G

    1992-04-01

    Findings are summarized from a study which set out to identify cognitive stumbling blocks in the user interface of a large computer system used by telephone operators in Australia. Intermittent observations were made of operators' actions in the workplace over a period of eight months before, during and after system implementation. Numerous weaknesses were identified in the user interface, but the most interesting aspect of the study turned out to be the analysis of the overall jobs operators are required to do, as a by-product of the intended study. The insight into operator job demands led to changes in job selection criteria and training, which were found to match actual job demands quite poorly at the time the study was conducted. The paper describes the process by which the usability assessment of the user-system interface led to a comprehensive job analysis. Supporting quantitative data are presented, together with anecdotal examples which demonstrate the importance of conducting systems analysis in the working context, thereby maximizing the ecological value of the resulting research data.

  11. Surfactant-Mediated Growth of Ge/Si(001) Interface Studied by XPD

    NASA Astrophysics Data System (ADS)

    Gunnella, R.; Castrucci, P.; Pinto, N.; Cucculelli, P.; Davoli, I.; Sébilleau, D.; de Crescenzi, M.

    The influence of Sb as a surfactant on the formation of Si/Ge interface is studied by means of XPD (X-ray photoelectron diffraction) and AED (Auger electron diffraction) from Ge and Si core levels. The technique employed is particularly suitable for checking the film tetragonal distortion, the growth morphology and the sharpness of the interface. We found a layer by layer growth mode for 3 ML of Ge on Si(001) and related values of strain of the film close to the value predicted by the elastic theory which enforces the use of such a surfactant to obtain high quality and sharp heterostructures. In addition, studying the influence of 3 ML of the Si cap layer on the 3 ML Ge, we obtain no indication of Ge segregation into the Si cap layer. Finally, evidences of quality degradation after high temperature (T > 600°C) annealing are shown.

  12. Evaluation of a novel Conjunctive Exploratory Navigation Interface for consumer health information: a crowdsourced comparative study.

    PubMed

    Cui, Licong; Carter, Rebecca; Zhang, Guo-Qiang

    2014-02-10

    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. 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). 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. 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). Wilcoxon signed-rank test (one

  13. Learning health 'safety' within non-technical skills interprofessional simulation education: a qualitative study.

    PubMed

    Gordon, Morris; Fell, Christopher W R; Box, Helen; Farrell, Michael; Stewart, Alison

    2017-01-01

    Healthcare increasingly recognises and focusses on the phenomena of 'safe practice' and 'patient safety.' Success with non-technical skills (NTS) training in other industries has led to widespread transposition to healthcare education, with communication and teamwork skills central to NTS frameworks. This study set out to identify how the context of interprofessional simulation learning influences NTS acquisition and development of 'safety' amongst learners. Participants receiving a non-technical skills (NTS) safety focussed training package were invited to take part in a focus group interview which set out to explore communication, teamwork, and the phenomenon of safety in the context of the learning experiences they had within the training programme. The analysis was aligned with a constructivist paradigm and took an interactive methodological approach. The analysis proceeded through three stages, consisting of open, axial, and selective coding, with constant comparisons taking place throughout each phase. Each stage provided categories that could be used to explore the themes of the data. Additionally, to ensure thematic saturation, transcripts of observed simulated learning encounters were then analysed. Six themes were established at the axial coding level, i.e., analytical skills, personal behaviours, communication, teamwork, context, and pedagogy. Underlying these themes, two principal concepts emerged, namely: intergroup contact anxiety - as both a result of and determinant of communication - and teamwork, both of which must be considered in relation to context. These concepts have subsequently been used to propose a framework for NTS learning. This study highlights the role of intergroup contact anxiety and teamwork as factors in NTS behaviour and its dissipation through interprofessional simulation learning. Therefore, this should be a key consideration in NTS education. Future research is needed to consider the role of the affective non-technical

  14. 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.

  15. Factors Influencing the Pursuit of IT Certifications: A Study of Minnesota Public Community and Technical College Students

    ERIC Educational Resources Information Center

    Wilkens, Eric S.

    2013-01-01

    This quantitative study attempted to understand the factors that influence Minnesota community and technical college students to pursue Information Technology (IT) certification. The study investigated the problem of determining the factors that influence Minnesota community and technical college students to pursue IT certification along with…

  16. Factors Influencing the Pursuit of IT Certifications: A Study of Minnesota Public Community and Technical College Students

    ERIC Educational Resources Information Center

    Wilkens, Eric S.

    2013-01-01

    This quantitative study attempted to understand the factors that influence Minnesota community and technical college students to pursue Information Technology (IT) certification. The study investigated the problem of determining the factors that influence Minnesota community and technical college students to pursue IT certification along with…

  17. Experimental study of the caprock / cement interface under CO2 geological storage conditions

    NASA Astrophysics Data System (ADS)

    Jobard, Emmanuel; Sterpenich, Jérôme; Pironon, Jacques; Randi, Aurélien; Caumon, Marie-Camille

    2013-04-01

    In the framework of CO2 geological storage, one of the critical point leading to possible massive CO2 leakages is the behavior of the interfaces crossed by the injection well. The lack of relevant data on the behavior of these interfaces (rock/well materials) in the presence of CO2 under high pressure and temperature conditions led to the development of a new experimental model called "Sandwich". These batch experiments consisted in putting a caprock (Callovo-Oxfordian claystone of the Paris Basin) in contact with cement (Portland class G) in the presence of supercritical CO2 with or without aqueous solution. The new experimental device was designed in order to follow the evolution of a clayey caprock, a Portland cement and their interface submitted to the acidic attack of carbonic acid through a study of the initial and final states. This model should help to document the behavior of interfaces in the proximal zone at the injection site. After one month of ageing at 80° C under 100 bar of CO2 pressure, the caprock, the cement and the interface between caprock and cement are investigated thanks to SEM, cathodoluminescence and Raman spectrometry. The main results reveal i) the influence of the presence of an aqueous solution since the carbonation mechanisms are quite different under dry and wet atmospheres, ii) the good cohesion of the different interfaces despite the carbonation of the cement, iii) the precipitation of different carbonate phases, which relates the changes in the chemistry of the solution to time, iv) the enrichment of silica in the cement phase submitted to the action of CO2 putting into evidence new mechanisms of in situ silica re-condensation, v) the very good behavior of the caprock despite the alkaline flux from cement and the acidic attack from the dissolved CO2. These experimental results will be compared to those obtained by geochemical simulations performed with PHREEQC. This study was financially supported by the French agency ANR (ANR-08

  18. Evaluation of a graphic interface to control a robotic grasping arm: a multicenter study.

    PubMed

    Laffont, Isabelle; Biard, Nicolas; Chalubert, Gérard; Delahoche, Laurent; Marhic, Bruno; Boyer, François C; Leroux, Christophe

    2009-10-01

    Laffont I, Biard N, Chalubert G, Delahoche L, Marhic B, Boyer FC, Leroux C. Evaluation of a graphic interface to control a robotic grasping arm: a multicenter study. Grasping robots are still difficult to use for persons with disabilities because of inadequate human-machine interfaces (HMIs). Our purpose was to evaluate the efficacy of a graphic interface enhanced by a panoramic camera to detect out-of-view objects and control a commercialized robotic grasping arm. Multicenter, open-label trial. Four French departments of physical and rehabilitation medicine. Control subjects (N=24; mean age, 33y) and 20 severely impaired patients (mean age, 44y; 5 with muscular dystrophies, 13 with traumatic tetraplegia, and 2 others) completed the study. None of these patients was able to grasp a 50-cL bottle without the robot. Participants were asked to grasp 6 objects scattered around their wheelchair using the robotic arm. They were able to select the desired object through the graphic interface available on their computer screen. Global success rate, time needed to select the object on the screen of the computer, number of clicks on the HMI, and satisfaction among users. We found a significantly lower success rate in patients (81.1% vs 88.7%; chi(2)P=.017). The duration of the task was significantly higher in patients (71.6s vs 39.1s; P<.001). We set a cut-off for the maximum duration at 79 seconds, representing twice the amount of time needed by the control subjects to complete the task. In these conditions, the success rate for the impaired participants was 65% versus 85.4% for control subjects. The mean number of clicks necessary to select the object with the HMI was very close in both groups: patients used (mean +/- SD) 7.99+/-6.07 clicks, whereas controls used 7.04+/-2.87 clicks. Considering the severity of patients' impairment, all these differences were considered tiny. Furthermore, a high satisfaction rate was reported for this population concerning the use of the

  19. 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.

  20. Characterizing complexity in socio-technical systems: a case study of a SAMU Medical Regulation Center.

    PubMed

    Righi, Angela Weber; Wachs, Priscila; Saurin, Tarcísio Abreu

    2012-01-01

    Complexity theory has been adopted by a number of studies as a benchmark to investigate the performance of socio-technical systems, especially those that are characterized by relevant cognitive work. However, there is little guidance on how to assess, systematically, the extent to which a system is complex. The main objective of this study is to carry out a systematic analysis of a SAMU (Mobile Emergency Medical Service) Medical Regulation Center in Brazil, based on the core characteristics of complex systems presented by previous studies. The assessment was based on direct observations and nine interviews: three of them with regulator of emergencies medical doctor, three with radio operators and three with telephone attendants. The results indicated that, to a great extent, the core characteristics of complexity are magnified) due to basic shortcomings in the design of the work system. Thus, some recommendations are put forward with a view to reducing unnecessary complexity that hinders the performance of the socio-technical system.

  1. How family carers engage with technical health procedures in the home: a grounded theory study.

    PubMed

    McDonald, Janet; McKinlay, Eileen; Keeling, Sally; Levack, William

    2015-07-06

    To explore the experiences of family carers who manage technical health procedures at home and describe their learning process. A qualitative study using grounded theory. 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. 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. 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. 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 behavioural responses to health technology during the training process

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

    DOE PAGES

    Burcklen, C.; Soufli, R.; Gullikson, E.; ...

    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

  3. 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.

  4. The Binding of Roxarsone at the Silica/Water Interface Studied with Second Harmonic Generation

    NASA Astrophysics Data System (ADS)

    Konek, Christopher; Ostrowski, David; Geiger, Franz

    2005-03-01

    Arsenic is a carcinogen that can also cause chronic poisoning when ingested via drinking water in quantities as low as 10 micrograms/L. In the US, organic arsenicals such as Roxarsone are commonly used as feed additives in the poultry industry. The use of poultry litter as fertilizer results in environmental arsenic deposition rates of up to 50 metric tons per year; the subsequent environmental fate of Roxarsone is unknown. We use second harmonic generation (SHG) to study the thermodynamics and kinetics of Roxarsone binding to environmentally relevant mineral oxide/water interfaces. Roxarsone binding to water/SiO2 interfaces is fully reversible, consistent with high Roxarsone mobility. Results from Langmuir isotherm measurements and surface SHG spectra are presented as well.

  5. 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.

  6. 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.

  7. 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.

  8. Studies of momentum and energy transfer across wavy gas-liquid interfaces. Final report

    SciTech Connect

    Dukler, A.E.

    1993-06-01

    Two phase gas-liquid flow and its associated interfaces exist in a wide variety of situations of importance to the Navy and this has prompted the study of the basic flow mechanics which underlie this complex process. The existence of wind-wave interactions over large bodies of water have long been recognized as a special case of two phase flow where the presence of the deformable interface plays a complex role in the generation of waves due to the action of the wind. Less well recognized, but of great importance, are situations of two phase flow which are found in components of power systems such as condensers, boilers refrigeration loops and cryogen lines. Here the characteristics of two phase flow are critical to the reliable design and safe operation of such systems.

  9. Cr/B{sub 4}C multilayer mirrors: Study of interfaces and X-ray reflectance

    SciTech Connect

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

    2016-03-28

    We present an experimental study of the effect of layer interfaces on the x-ray reflectance in Cr/B{sub 4}C 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 B{sub 4}C-on-Cr interface, which we modeled with a 1–1.5 nm thick interfacial layer. Reflectance measurements in the vicinity of the Cr L{sub 2,3} absorption edge demonstrate fine structure that is not predicted by simulations using the currently tabulated refractive index (optical constants) values for Cr.

  10. Iranian nurses' experience of essential technical competences in disaster response: A qualitative content analysis study.

    PubMed

    Aliakbari, Fatemeh; Bahrami, Masoud; Aein, Fereshteh; Khankeh, Hamidreza

    2014-11-01

    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. 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. 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. 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.

  11. 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

  12. 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.

  13. Thermal transport study across interface “nanostructured solid surface / fluid” by photoacoustic technique

    NASA Astrophysics Data System (ADS)

    Voitenko, K.; Isaiev, M.; Pastushenko, A.; Andrusenko, D.; Kuzmich, A.; Lysenko, V.; Burbelo, R.

    2017-01-01

    In the paper the experimental study of heat transport across the interface “porous silicon/liquid” by photoacoustic technique is reported. Two cases with and without liquid covering of porous silicon surface were considered. Thermal perturbations were excited at the surface of porous silicon as a result of absorption of the light with modulated intensity. The resulting thermal-elastic stresses arising in the system were registered with piezoelectric transducer. The amplitude-frequency dependencies of the voltage on the piezoelectric electrodes were measured. The presence of the liquid film leads to decreasing of the amplitude of photoacoustic signal as a result of the thermal energy evacuation from the porous silicon into the liquid. The experimental dependencies were fitted with the results of simulation that takes into account heat fluxes separation at the porous silicon/liquid interface. With the presented method one can precisely measure heat fluxes transferred from the solid into contacting fluid. Moreover, the presented approach can be easily adopted for the thermal conductivity study of the different nanofluids as well as thermal resistance at the interface nanostructured solid/fluid.

  14. Training to use a commercial brain-computer interface as access technology: a case study.

    PubMed

    Taherian, Sarvnaz; Selitskiy, Dmitry; Pau, James; Davies, T Claire; Owens, R Glynn

    2016-01-01

    This case study describes how an individual with spastic quadriplegic cerebral palsy was trained over a period of four weeks to use a commercial electroencephalography (EEG)-based brain-computer interface (BCI). The participant spent three sessions exploring the system, and seven sessions playing a game focused on EEG feedback training of left and right arm motor imagery and a customised, training game paradigm was employed. The participant showed improvement in the production of two distinct EEG patterns. The participant's performance was influenced by motivation, fatigue and concentration. Six weeks post-training the participant could still control the BCI and used this to type a sentence using an augmentative and alternative communication application on a wirelessly linked device. The results from this case study highlight the importance of creating a dynamic, relevant and engaging training environment for BCIs. Implications for Rehabilitation Customising a training paradigm to suit the users' interests can influence adherence to assistive technology training. Mood, fatigue, physical illness and motivation influence the usability of a brain-computer interface. Commercial brain-computer interfaces, which require little set up time, may be used as access technology for individuals with severe disabilities.

  15. Bulk and interface recombination in planar lead halide perovskite solar cells: A Drift-Diffusion study

    NASA Astrophysics Data System (ADS)

    Olyaeefar, Babak; Ahmadi-Kandjani, Sohrab; Asgari, Asghar

    2017-10-01

    A theoretical approach based on Drift-Diffusion equations is presented to study planar mixed lead halide perovskite solar cells. Updated physical parameters such as permittivity, mobility, effective density of states and doping density is employed in simulations. Current-voltage curve data for two experimental sample is imported and through fitting with the model, density of bulk and interface defects is calculated. We obtain the bulk defect density around 1016 cm-3 and surface recombination velocities in the range of 10 cm/s. These values which are in good agreement with experimental measurements and considerably deviated from previous theoretical studies, verify the model and adopted constants. Shockley-Queisser limit is also presented as the ideal device and the effect of bulk and interface defects are presented as loss factors that cause departure from this limit. Our simulations conclude that the overall efficiency of perovskite solar cells is mainly governed by the open-circuit voltage and also identify the interface defects as the major loss factor in these devices.

  16. Chlorhexidine stabilizes the adhesive interface: a 2 year in vitro study

    PubMed Central

    Breschi, Lorenzo; Mazzoni, Annalisa; Nato, Fernando; Carrilho, Marcela; Visintini, Erika; Tjäderhane, Leo; Ruggeri, Alessandra; Tay, Franklin R; De Stefano Dorigo, Elettra; Pashley, David H

    2013-01-01

    Objectives This study evaluated the role of endogenous dentin MMPs in auto-degradation of collagen fibrils within adhesive-bonded interfaces. The null hypotheses tested were that adhesive blends or chlorhexidine digluconate (CHX) application does not modify dentin MMPs activity and that CHX used as therapeutic primer does not improve the stability of adhesive interfaces over time. Methods Zymograms of protein extracts from human dentin powder incubated with Adper Scotchbond 1XT (SB1XT) on untreated or 0.2–2% CHX treated dentin were obtained to assay dentin MMPs activity. Microtensile bond strength and interfacial nanoleakage expression of SB1XT bonded interfaces (with or without CHX pre-treatment for 30s on the etched surface) were analyzed immediately and after 2 yr of storage in artificial saliva at 37°C. Results Zymograms showed that application of SB1XT to human dentin powder increases MMP-2 activity, while CHX pre-treatment inhibited all dentin gelatinolytic activity, irrespective from the tested concentration. CHX significantly lowered the loss of bond strength and nanoleakage seen in acid-etched resin-bonded dentin artificially aged for 2 yr. Significance The study demonstrates the active role of SB1XT in dentin MMP-2 activation and the efficacy of CHX inhibition of MMPs even if used at low concentration (0.2%). PMID:20045177

  17. A novel gas-vacuum interface for environmental molecular beam studies.

    PubMed

    Johansson, Sofia M; Kong, Xiangrui; Papagiannakopoulos, Panos; Thomson, Erik S; Pettersson, Jan B C

    2017-03-01

    Molecular beam techniques are commonly used to obtain detailed information about reaction dynamics and kinetics of gas-surface interactions. These experiments are traditionally performed in vacuum and the dynamic state of surfaces under ambient conditions is thereby excluded from detailed studies. Herein we describe the development and demonstration of a new vacuum-gas interface that increases the accessible pressure range in environmental molecular beam (EMB) experiments. The interface consists of a grating close to a macroscopically flat surface, which allows for experiments at pressures above 1 Pa including angularly resolved measurements of the emitted flux. The technique is successfully demonstrated using key molecular beam experiments including elastic helium and inelastic water scattering from graphite, helium and light scattering from condensed adlayers, and water interactions with a liquid 1-butanol surface. The method is concluded to extend the pressure range and flexibility in EMB studies with implications for investigations of high pressure interface phenomena in diverse fields including catalysis, nanotechnology, environmental science, and life science. Potential further improvements of the technique are discussed.

  18. A novel gas-vacuum interface for environmental molecular beam studies

    NASA Astrophysics Data System (ADS)

    Johansson, Sofia M.; Kong, Xiangrui; Papagiannakopoulos, Panos; Thomson, Erik S.; Pettersson, Jan B. C.

    2017-03-01

    Molecular beam techniques are commonly used to obtain detailed information about reaction dynamics and kinetics of gas-surface interactions. These experiments are traditionally performed in vacuum and the dynamic state of surfaces under ambient conditions is thereby excluded from detailed studies. Herein we describe the development and demonstration of a new vacuum-gas interface that increases the accessible pressure range in environmental molecular beam (EMB) experiments. The interface consists of a grating close to a macroscopically flat surface, which allows for experiments at pressures above 1 Pa including angularly resolved measurements of the emitted flux. The technique is successfully demonstrated using key molecular beam experiments including elastic helium and inelastic water scattering from graphite, helium and light scattering from condensed adlayers, and water interactions with a liquid 1-butanol surface. The method is concluded to extend the pressure range and flexibility in EMB studies with implications for investigations of high pressure interface phenomena in diverse fields including catalysis, nanotechnology, environmental science, and life science. Potential further improvements of the technique are discussed.

  19. Metal-ceramic interfaces studied with high-resolution transmission electron microscopy

    SciTech Connect

    De Hosson, J.T.M.; Groen, H.B.; Kooi, B.J.; Vitek, V.

    1999-11-12

    How the core structure of an interface dislocation network depends on both misfit and bond strength across the interface is investigated. It is shown that, in principle at least, it is possible to assess the bond strength by investigating the atomic structure of the dislocation cores. As examples, the misfit-dislocation structures at Ag/Mn{sub 3}O{sub 4}, Cu/MnO interfaces formed by parallel close-packed planes of Ag or Cu and O obtained by internal oxidation were studied using HRTEM and lattice static calculations. The lattice static calculations are instrumental in indicating the possible dislocation network and their results served as input for HRTEM image simulations which are then compared with experimental HRTEM images. In addition, the influence of dissolution of a segregating element (Sb) in these systems was also studied using HRTEM. The influence on Mn{sub 3}O{sub 4} precipitates in Ag is distinct, namely: (1) the initial precipitates, sharply facetted by solely {l{underscore}brace}111{r{underscore}brace}, are changed into a globular shape with sometimes also short {l{underscore}brace}220{r{underscore}brace} and (002) facets, and (2) a partial reduction of Mn{sub 3}O{sub 4} into MnO occurs for a part of the precipitates. Further Sb appeared to prevent Oswald ripening of the precipitates.

  20. A Molecular Dynamics Study on the Local Structure of Liquid-Vapor Interface of Water and L-J Fluid

    NASA Astrophysics Data System (ADS)

    Kikugawa, Gota; Takagi, Shu; Matsumoto, Yoichiro; Ohara, Taku

    Microscopic structures of a liquid-vapor interface are investigated by molecular dynamics simulations. In the previous studies, we proposed the local and instantaneous definition of the interface at the molecular level, which can capture the thermal fluctuation of the interface. By using this definition, the layering structure of water molecules at the interface was found, in other words, the structurization phenomena of water at the molecular level were clearly seen as usually found at the liquid-solid interface. In this study, we investigated the liquid-vapor interface of Lenard-Jones fluid. The effect of well depth of L-J potential parameter on the structure was also studied. Although the structurization was found at the L-J fluid as well as water, characteristic of this structure was clearly different from that of water. We consider that the difference is ascribed to the intrinsic structure of liquid and associative trend of molecules. We also discussed the anisotropic characteristics of the molecular diffusion at the interface. The anisotropy of the translational diffusion at the interface of water is stronger than that of the L-J fluid.

  1. 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.

  2. 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.

  3. Technical efficiency of public district hospitals and health centres in Ghana: a pilot study

    PubMed Central

    Osei, Daniel; d'Almeida, Selassi; George, Melvill O; Kirigia, Joses M; Mensah, Ayayi Omar; Kainyu, Lenity H

    2005-01-01

    Background The Government of Ghana has been implementing various health sector reforms (e.g. user fees in public health facilities, decentralization, sector-wide approaches to donor coordination) in a bid to improve efficiency in health care. However, to date, except for the pilot study reported in this paper, no attempt has been made to make an estimate of the efficiency of hospitals and/or health centres in Ghana. The objectives of this study, based on data collected in 2000, were: (i) to estimate the relative technical efficiency (TE) and scale efficiency (SE) of a sample of public hospitals and health centres in Ghana; and (ii) to demonstrate policy implications for health sector policy-makers. Methods The Data Envelopment Analysis (DEA) approach was used to estimate the efficiency of 17 district hospitals and 17 health centres. This was an exploratory study. Results Eight (47%) hospitals were technically inefficient, with an average TE score of 61% and a standard deviation (STD) of 12%. Ten (59%) hospitals were scale inefficient, manifesting an average SE of 81% (STD = 25%). Out of the 17 health centres, 3 (18%) were technically inefficient, with a mean TE score of 49% (STD = 27%). Eight health centres (47%) were scale inefficient, with an average SE score of 84% (STD = 16%). Conclusion This pilot study demonstrated to policy-makers the versatility of DEA in measuring inefficiencies among individual facilities and inputs. There is a need for the Planning and Budgeting Unit of the Ghana Health Services to continually monitor the productivity growth, allocative efficiency and technical efficiency of all its health facilities (hospitals and health centres) in the course of the implementation of health sector reforms. PMID:16188021

  4. A Preliminary Study: USMC Tactical Communications Technical Control Needs for the Landing Force Integrated Communications System.

    DTIC Science & Technology

    1985-09-01

    corrected thereby making the TSQ-111 a viable alternative choice for the long term . There is too little lead time and high acquisition risk (quantity...SaCUIWTY CLASSIFICATION OF THIS PAGE (hM 0a Emeee 20. long term (1991+) eras of service. Examined...are the technical control functional requirements for both the transitional near term and the eventual long term digital i systems. The study raises

  5. Synchrotron radiation photoemission study of the ultrathin Cs/InN interface

    NASA Astrophysics Data System (ADS)

    Benemanskaya, G. V.; Lapushkin, M. N.; Timoshnev, S. N.; Nelubov, A. V.

    2015-09-01

    Electronic structure of the ultrathin Cs/n-InN interface has been studied in situ via synchrotron-based photoemission spectroscopy by excitation in the energy range of 70-400 eV. Changes in the In 4d, Cs 4d, Cs 5p, N 2s core level spectra and in the surface state spectra have been revealed under different cesium coverages. The intrinsic surface state for the clean InN surface at binding energy of 2.5 eV (SS1) is found to attenuate during the Cs adsorption. Simultaneously the Cs induced surface state at binding energy of 0.9 eV (SS2) arises. For the Cs/InN interface, the In 4d peak displays the strong core level shift and the appearance of an additional In 4d peak originated from In-Cs interface bonding. Change in the surface electronic structure of the InN caused by Cs adsorption is found to originate predominantly from suppression of the intrinsic surface state concerned with the local interaction of In dangling bonds and Cs adatoms.

  6. Study of a new bone-targeting titanium implant–bone interface

    PubMed Central

    Liu, Xiangning; Zhang, Ye; Li, Shaobing; Wang, Yayu; Sun, Ting; Li, Zejian; Cai, Lizhao; Wang, Xiaogang; Zhou, Lei; Lai, Renfa

    2016-01-01

    New strategies involving bone-targeting titanium (Ti) implant–bone interface are required to enhance bone regeneration and osseointegration for orthopedic and dental implants, especially in osteoporotic subjects. In this study, a new dual-controlled, local, bone-targeting delivery system was successfully constructed by loading tetracycline-grafted simvastatin (SV)-loaded polymeric micelles in titania nanotube (TNT) arrays, and a bone-targeting Ti implant–bone interface was also successfully constructed by implanting the delivery system in vivo. The biological effects were evaluated both in vitro and in vivo. The results showed that Ti surfaces with TNT–bone-targeting micelles could promote cytoskeletal spreading, early adhesion, alkaline phosphatase activity, and extracellular osteocalcin concentrations of rat osteoblasts, with concomitant enhanced protein expression of bone morphogenetic protein (BMP)-2. A single-wall bone-defect implant model was established in normal and ovariectomized rats as postmenopausal osteoporosis models. Microcomputed tomography imaging and BMP-2 expression in vivo demonstrated that the implant with a TNT-targeting micelle surface was able to promote bone regeneration and osseointegration in both animal models. Therefore, beneficial biological effects were demonstrated both in vitro and in vivo, which indicated that the bone-targeting effects of micelles greatly enhance the bioavailability of SV on the implant–bone interface, and the provision of SV-loaded targeting micelles alone exhibits the potential for extensive application in improving local bone regeneration and osseointegration, especially in osteoporotic subjects. PMID:27932879

  7. Compressive osseointegration promotes viable bone at the endoprosthetic interface: retrieval study of Compress® implants

    PubMed Central

    Kramer, M. J.; Tanner, B. J.; Horvai, A. E.

    2007-01-01

    The Compress® implant (Biomet, Warsaw, IN) is an innovative device developed to enable massive endoprosthetic fixation through the application of compressive forces at the bone-implant interface. This design provides immediate, stable anchorage and helps to avoid the long-term complication of aseptic loosening secondary to stress shielding and particle-induced osteolysis seen in conventional, stemmed megaprostheses. The purpose of our study was to evaluate the in vivo biological effects of the high compressive forces attained. Twelve consecutive Compress® patients undergoing revision surgery for infection, periprosthetic fracture, or local tumour recurrence were reviewed in order to exclude the possibility of osteonecrosis at the prosthetic interface. Compressive forces ranged from 400–800 lb. Duration of implantation averaged 3.3 years (range 0.4–12.2 years). Two patients with infection demonstrated loosening at the bone-prosthetic interface; otherwise, there was no radiographic evidence of prosthetic failure in any of the patients. No patient demonstrated histological evidence of osteonecrosis. In fact, new woven bone and other findings consistent with viable bone were noted in all of the retrieved specimens. PMID:17576554

  8. A Comparative Study of the Effect of Surfactant and Temperature in Fluid Interfaces

    NASA Astrophysics Data System (ADS)

    Cortes-Estrada, Aldo H.; Ibarra-Bracamontes, Laura A.; Aguilar-Corona, Alicia; Viramontes-Gamboa, Gonzalo

    2016-11-01

    A fluid interface is the boundary region formed when two immiscible fluids come into contact. One of the most important properties of fluid interfaces is the interfacial tension. The interfacial tension between two fluids can be modified by the presence of surfactant. In addition, the temperature is a relevant factor that can also modify the interfacial properties. In this work the behavior of the interface formed by oil and water in the presence of surfactant at different temperatures is presented. Interfacial tension measurements were obtained by the Pendant Drop technique. Two types of surfactant were tested, Sodium Dodecyl Sulfate (SDS) as a hydrophilic surfactant, and Sorbitan Monooleate (Span 80) as a lipophilic surfactant. The range of variations in temperature was from 25 to 60 Celsius degree. Hexane or Dodecane was used as the oil phase. The main results showed that the lipophilic surfactant showed a greater efficiency with respect to the hydrophilic surfactant used. As the temperature increased in the range considered an exponential decay for the interfacial tension was observed. This decay was dominated by the surfactant concentration. This study was supported by the Mexican Council of Science and Technology (CONACyT) and by the Scientific Research Coordination of the University of Michoacan in Mexico.

  9. 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.

  10. Study of a new bone-targeting titanium implant-bone interface.

    PubMed

    Liu, Xiangning; Zhang, Ye; Li, Shaobing; Wang, Yayu; Sun, Ting; Li, Zejian; Cai, Lizhao; Wang, Xiaogang; Zhou, Lei; Lai, Renfa

    New strategies involving bone-targeting titanium (Ti) implant-bone interface are required to enhance bone regeneration and osseointegration for orthopedic and dental implants, especially in osteoporotic subjects. In this study, a new dual-controlled, local, bone-targeting delivery system was successfully constructed by loading tetracycline-grafted simvastatin (SV)-loaded polymeric micelles in titania nanotube (TNT) arrays, and a bone-targeting Ti implant-bone interface was also successfully constructed by implanting the delivery system in vivo. The biological effects were evaluated both in vitro and in vivo. The results showed that Ti surfaces with TNT-bone-targeting micelles could promote cytoskeletal spreading, early adhesion, alkaline phosphatase activity, and extracellular osteocalcin concentrations of rat osteoblasts, with concomitant enhanced protein expression of bone morphogenetic protein (BMP)-2. A single-wall bone-defect implant model was established in normal and ovariectomized rats as postmenopausal osteoporosis models. Microcomputed tomography imaging and BMP-2 expression in vivo demonstrated that the implant with a TNT-targeting micelle surface was able to promote bone regeneration and osseointegration in both animal models. Therefore, beneficial biological effects were demonstrated both in vitro and in vivo, which indicated that the bone-targeting effects of micelles greatly enhance the bioavailability of SV on the implant-bone interface, and the provision of SV-loaded targeting micelles alone exhibits the potential for extensive application in improving local bone regeneration and osseointegration, especially in osteoporotic subjects.

  11. Study on NiO/Fe interface with X-ray photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Feng, Chun; Zhang, Jing-Yan; Teng, Jiao; Wang, Fu-Ming

    2010-12-01

    Different monolayers (ML) of Fe atoms were deposited on NiO (001) substrates or NiO underlayers using molecular beam epitaxy (MBE), pulse laser deposition (PLD), and magnetron sputtering (MS). The magnetic properties and microstructure of the films were studied. The apparent magnetic dead layer (MDL) is found to exist at the NiO/Fe interfaces of the MBE sample (about 2 ML MDL), the PLD sample (about 3 ML MDL), and the MS sample (about 4 ML MDL). X-ray photoelectron spectroscopy indicates the presence of ionic Fe (Fe2+ or Fe3+) and metallic Ni at the NiO/Fe interfaces, which may be due to the chemical reactions between Fe and NiO layers. This also leads to the formation of MDL. The thickness of the MDL and the reaction products are related with the deposition energy of the atoms on the substrates. The interfacial reactions are effectively suppressed by inserting a thin Pt layer at the NiO/Fe interface.

  12. Studies of Athabasca asphaltene Langmuir films at air-water interface.

    PubMed

    Zhang, Li Yan; Lawrence, Steven; Xu, Zhenghe; Masliyah, Jacob H

    2003-08-01

    Asphaltenes are present in heavy oils and bitumen. They are a mixture of hydrocarbons having complex structures of polyaromatic rings and short side chains. In general, the high-molecular-weight asphaltene is the most aromatic fraction with the highest number of side chains and the low-molecular-weight asphaltene contains the lowest number of side chains, while the number of side chains of the whole asphaltene fraction lies in between. In this study, asphaltenes were extracted and/or fractionated from Athabasca oil sand bitumen. Subfractions of high and low molecular weight and the whole asphaltenes were characterized using a Langmuir trough and complementary techniques such as VPO, FTIR, AFM, and contact angle measurements. At an air-water interface, amphiphilic asphaltene molecules can form a monolayer. Various fractions (high, low, and whole) of the asphaltene molecules behave similarly at the air-water interface, characterized by close resemblance of their surface pressure-area, hysteresis, and relaxation isotherms. The high-molecular-weight asphaltene is the most expanded fraction, while the low-molecular-weight asphaltene fraction is the most condensed, with the whole asphaltene lying in between. At the air-water interface a monolayer of the low-molecular-weight asphaltene relaxes at a faster rate than one of the high-molecular-weight asphaltene.

  13. 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).

  14. Study of surface charge density on solid/liquid interfaces by modulating the electrical double layer

    NASA Astrophysics Data System (ADS)

    Pak, Hyuk Kyu; Moon, Jong Kyun

    2014-11-01

    A solid surface in contact with water or aqueous solution usually carries specific electric charges. These surface charges attract counter ions from the liquid side. Since the geometry of opposite charge distribution parallel to the solid/liquid interface is similar to that of a capacitor, it is called an electrical double layer capacitor (EDLC). Therefore, there is an electrical potential difference across an EDLC in equilibrium. When a liquid bridge is formed between two conducting plates, the system behaves as two serially connected EDLCs. In this work, we propose a new method for investigating the surface charge density on solid/liquid interfaces. By mechanically modulating the electrical double layers and simultaneously applying a DC bias voltage across the plates, an AC electric current can be generated. By measuring the voltage difference between the plates as a function of bias voltage, we can study the surface charge density on solid/liquid interfaces. Our experimental results agree very well with the simple equivalent circuit model proposed here. Furthermore, using this method, one can determine the polarity of the adsorbed state on the solid surface depending on the material used. This work was supported by Center for Soft and Living Matter through IBS program in Korea.

  15. 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.

  16. Uranyl adsorption at the muscovite (mica)/water interface studied by second harmonic generation.

    PubMed

    Saslow Gomez, Sarah A; Jordan, David S; Troiano, Julianne M; Geiger, Franz M

    2012-10-16

    Uranyl adsorption at the muscovite (mica)/water interface was studied by second harmonic generation (SHG). Using the nonresonant χ(3) technique and the Gouy-Chapman model, the initial surface charge density of the mica surface was determined to be -0.022(1) C/m(2) at pH 6 and in the presence of dissolved carbonate. Under these same conditions, uranyl adsorption isotherms collected using nonresonant χ(3) experiments and resonantly enhanced SHG experiments that probe the ligand-to-metal charge transfer bands of the uranyl cation yielded a uranyl binding constant of 3(1) × 10(7) M(-1), corresponding to a Gibbs free energy of adsorption of -52.6(8) kJ/mol, and a maximum surface charge density at monolayer uranyl coverage of 0.028(3) C/m(2). These results suggest favorable adsorption of uranyl ions to the mica interface through strong ion-dipole or hydrogen interactions, with a 1:1 uranyl ion to surface site ratio that is indicative of monovalent cations ((UO(2))(3)(OH)(5)(+), (UO(2))(4)(OH)(7)(+), UO(2)OH(+), UO(2)Cl(+), UO(2)(CH(3)COO(-))(+)) binding at the interface, in addition to neutral uranyl species (UO(2)(OH)(2) and UO(2)CO(3)). This work provides benchmark measurements to be used in the improvement of contaminant transport modeling.

  17. Study of the dynamical approach to the interface localization delocalization transition of the confined Ising model

    NASA Astrophysics Data System (ADS)

    Albano, Ezequiel V.; DeVirgiliis, Andres; Müller, Marcus; Binder, Kurt

    2004-06-01

    Confined magnetic Ising films in a L × D geometry (L \\ll D ), with short-range competing magnetic fields (h) acting at opposite walls along the D-direction, exhibit a slightly rounded localization-delocalization transition of the interface between domains of different orientations that runs parallel to the walls. This transition is the precursor of a wetting transition that occurs in the limit of infinite film thickness (L \\to \\infty ) at the critical curve Tw(h). For TTw(h)) such an interface is bounded (unbounded) to the walls, while right at Tw(h) the interface is freely fluctuating around the centre of the film. Starting from disordered configurations, corresponding to T=\\infty , we quench to the wetting critical temperature and study the dynamics of the approach to the stationary regime by means of extensive Monte Carlo simulations. It is found that for all layers parallel to the wall (rows), the row magnetizations exhibit a peak at a time \\tau _{\\max } \\propto L^{2} and subsequently relax to the stationary, equilibrium behaviour. The characteristic time for such a relaxation scales as \\tau_{\\mathrm {R}} \\propto L^{4} , as expected from theoretical arguments, that are discussed in detail.

  18. 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…

  19. 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…

  20. Technical Services on the Net: Where Are We Now? A Comparative Study of Sixty Web Sites of Academic Libraries

    ERIC Educational Resources Information Center

    Wang, Jianrong; Gao, Vera

    2004-01-01

    This study examines sixty academic libraries' Web sites and finds that 80 percent of them do not have a technical services' homepage. Data reveal that institution's status might be a factor in whether a library has such a page. Further content analysis suggests there is an appropriate and useful public service role that technical services…

  1. 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…

  2. Experimental study of the seismoelectric interface response in wedge and cavity models

    NASA Astrophysics Data System (ADS)

    Peng, Rong; Di, Bangrang; Wei, Jianxin; Ding, Pinbo; Zhao, Jianguo; Pan, Xiao; Liu, Zichun

    2017-09-01

    We have built an experimental device and performed seismoelectric physical modelling experiments on sandstone rock models with different geometries. Our aims are (1) to gain insight into the interface response behaviour of rock models with different geometry, (2) to illustrate the amplitude characteristics of the interface responses induced by incident waves and reflections of multiple interfaces and (3) to investigate the polarity reversal of the interface responses generated at different interfaces. For experimental preciseness, we conducted a series of control measurements on sandstone to confirm that we indeed measured the seismoelectric conversion, and gained insight on the influence of the surface wave coseismic signals and the P-wave coseismic signals. The seismoelectric results of wedge model verify that a thin layer structure can enhance the seismoelectric signal. The strength differences between the incident-wave-induced signals and the reflection-induced signals have significant effects on the interpretation of underground structures and interfaces. The incident-wave-induced signals at the lower interface may be neglected easily for its small amplitude, while the reflection-induced signals at the upper interface with a longer traveltime may be regarded as a new event of a lower interface for its large amplitude. Therefore, the depth of interfaces is likely to be misinterpreted. Our experiments show that the polarity reversal of interface responses is affected by receiver positions. For a given interface measured with electrodes at different depths in a borehole, seismoelectric interface responses recorded by electrodes on two sides of an interface have the opposite polarity. For multiple interfaces measured with one electrode, the polarity of the interface responses from the interfaces above the electrode reverses with that from the interfaces below the electrode. The variation characteristics of the polarity reversal can help to correct the polarity

  3. 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).

  4. The Development of Technical and Vocational Education in Bangladesh--A Case Study in Quality Improvement. Case Studies on Technical and Vocational Education in Asia and the Pacific.

    ERIC Educational Resources Information Center

    Rafique, A.

    The National Council for Skill Development and Training and the Bangladesh Technical Education Board (BTEB) determine the technical vocational education and training (TVET) policy guidelines and implementation strategies. The TVET programs run by the government agencies, nongovernmental agencies, and private institutions are nonstandard and…

  5. Interfacing biological macromolecules with carbon nanotubes and silicon surfaces: a computer modelling and dynamic simulation study

    NASA Astrophysics Data System (ADS)

    Tatke, S. S.; Renugopalakrishnan, V.; Prabhakaran, M.

    2004-10-01

    Proteins are naturally occurring nanosystems, optimized by the process of evolution. Biotechnology of protein based nanostructures offers vast opportunities to re-engineer and combine them with other nanomaterials for technological applications. Our primary interest is to interface proteins like bacteriorhodopsin (bR) with carbon nanotubes and silicon surfaces for application in storage devices and biosensors. We have carried out extensive computer simulations to study the dynamics of carbon nanotubes and their interaction with proteins. The immobilization of the protein on the carbon nanotubes is carried out by either covalent bonding or aromatic pgr stacking. Our simulation studies reveal the difference between the pgr stacking and covalent bonding.

  6. A preliminary study on characterisation of finger interface kinetics using a pressure and shear sensor system.

    PubMed

    Hale, Nicholas; Valero, Maria; Tang, Jinghua; Moser, David; Jiang, Liudi

    2017-08-01

    Our hands constantly handle objects throughout our lives, where a crucial component of this interaction is the detection of grasping (pressure) and slipping (shear) of the object. While there have been a large amount of studies using pressure sensors for grasping detection, synchronised pressure and shear detection at the finger/object interface is still needed. This study aims to assess the feasibility of a sensor system designed to detect both pressure and shear at the fingertip/object interface via a single subject test. Descriptive study, proof of concept. One healthy subject participated in the study and was asked to perform a single finger test protocol and a simple hand test protocol. The corresponding multidirectional loads at the fingertip/object interface were measured in real time using a pressure and shear sensor system. Results from the finger test protocol show peak values of up to approximately 50 kPa (5 N) and 30 kPa (3 N) of pressure for each test, respectively. Results from the hand test protocol show a pressure and shear profile that shows a large increase in grip force during the initial grasping of the object, with a peak pressure of approximately 50 kPa (5 N). The pressure and shear profile demonstrates that the load is not evenly distributed across all digits. This study provides evidence that the reported sensor system has sufficient resolution, dynamic response and load capability to capture biomechanical information during basic protocols and hand-grasping tasks. Clinical relevance The presented sensor system could be potentially used as a tool for measuring and evaluating hand function and could be incorporated into a prosthetic hand as a tactile feedback system.

  7. 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.

  8. 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.

  9. The effect of multiple layers of linens on surface interface pressure: results of a laboratory study.

    PubMed

    Williamson, Rachel; Lachenbruch, Charlie; Vangilder, Catherine

    2013-06-01

    Underpads and layers of linens are frequently placed under patients who are incontinent, have other moisture-related issues, and/or are immobile and cannot reposition independently. Many of these patients are also at risk for pressure ulcers and placed on pressure-redistribution surfaces. The purpose of this study was to measure the effects of linens and incontinence pads on interface pressure. Interface sacral pressures were measured (mm Hg) using a mannequinlike pelvic indenter that has pressure transducers integrated into the unit and is covered with a soft flesh-like elastomer. The indenter was loaded to simulate a median-weight male (80 kg/176 lb), and the testing was performed at head-of bed (HOB) angles of 0°, 30°, and 45°. Two different surfaces, a high performance low-air-loss support (LAL) surface and a standard foam support surface, were used and covered with a fitted sheet (FS) only or a combination of the FS and various incontinence pads and transfer sheets. Linen combinations typically used for relatively immobile patients (n = 4), moisture management (n = 4), and moisture management and immobility (n = 1) were tested, as was the heavy use of linens/pads (nine layers, n = 1). All combinations were tested 10 times at HOB angles of 0°, 30°, and 45°. The highest pressure observed was recorded (peak pressure). Ninety five percent (95%) confidence interval (CI) surrounding the mean of the 10 trials for each combination was calculated using the t-distribution; differences between means for all surface combinations were determined using one-way ANOVA with follow-up Fisher Hayter test. Results indicated that each incontinence pad, transfer sheet, or combination of linens significantly increased the mean peak sacral pressure when compared to a single FS on both the low-air-loss surface and the foam surface, regardless of the head-of-bed angle. The magnitude of peak sacral interface pressure increase for the LAL surface at 30° head-of-bed angle was 20

  10. 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

  11. Technical Reproducibility of Genotyping SNP Arrays Used in Genome-Wide Association Studies

    PubMed Central

    Hong, Huixiao; Xu, Lei; Liu, Jie; Jones, Wendell D.; Su, Zhenqiang; Ning, Baitang; Perkins, Roger; Ge, Weigong; Miclaus, Kelci; Zhang, Li; Park, Kyunghee; Green, Bridgett; Han, Tao; Fang, Hong; Lambert, Christophe G.; Vega, Silvia C.; Lin, Simon M.; Jafari, Nadereh; Czika, Wendy; Wolfinger, Russell D.; Goodsaid, Federico; Tong, Weida; Shi, Leming

    2012-01-01

    During the last several years, high-density genotyping SNP arrays have facilitated genome-wide association studies (GWAS) that successfully identified common genetic variants associated with a variety of phenotypes. However, each of the identified genetic variants only explains a very small fraction of the underlying genetic contribution to the studied phenotypic trait. Moreover, discordance observed in results between independent GWAS indicates the potential for Type I and II errors. High reliability of genotyping technology is needed to have confidence in using SNP data and interpreting GWAS results. Therefore, reproducibility of two widely genotyping technology platforms from Affymetrix and Illumina was assessed by analyzing four technical replicates from each of the six individuals in five laboratories. Genotype concordance of 99.40% to 99.87% within a laboratory for the sample platform, 98.59% to 99.86% across laboratories for the same platform, and 98.80% across genotyping platforms was observed. Moreover, arrays with low quality data were detected when comparing genotyping data from technical replicates, but they could not be detected according to venders’ quality control (QC) suggestions. Our results demonstrated the technical reliability of currently available genotyping platforms but also indicated the importance of incorporating some technical replicates for genotyping QC in order to improve the reliability of GWAS results. The impact of discordant genotypes on association analysis results was simulated and could explain, at least in part, the irreproducibility of some GWAS findings when the effect size (i.e. the odds ratio) and the minor allele frequencies are low. PMID:22970228

  12. Study of laser-generated interfacial waves and their interaction with a defect at solid-fluid interface

    NASA Astrophysics Data System (ADS)

    Yan, Zhao; Bixing, Zhang; Liping, Xue

    2016-01-01

    The analysis of the pulsed laser generation of interfacial waves propagating along a plane solid-fluid interface and their interaction with a defect (notch) on the interface are presented. The solid-fluid interface motion due to laser-generated interfacial waves including leaky Rayleigh and Scholte wave is simulated by finite element method for two configurations, one is "hard solid-fluid" interface, like steel-water, the other one is "soft solid-fluid" interface, like Plexiglas-water. And then their interaction with a notch-like defect in the interface has also been studied. Two series defects are introduced into the interface. One is with same width but different depth, and the other one with the same depth but different width. For hard and soft solid-fluid configurations, leaky Rayleigh and Scholte wave is severely affected by the notch, respectively. In contrast, Scholte and leaky Rayleigh wave experiences almost no influence for hard and soft solid-fluid interface. The results may lead to an application for defect identification and nondestructive materials characterization.

  13. Technical report submitted to the Department of Energy, Washington, DC on determination of net CO/sub 2/ flux across air-sea interface

    SciTech Connect

    Takahashi, T.; Chipman, D.; Smethie, W. Jr.

    1983-07-08

    The net CO/sub 2/ flux across the air-sea interface has been determined in December, 1982, in the Caribbean Sea and the tropical North Atlantic Ocean using the pCO/sub 2/ and radon-222 methods. The thermodynamic driving force for CO/sub 2/ gas transfer has been characterized in terms of the difference between the CO/sub 2/ partial pressures, pCO/sub 2/, in the surface ocean water and the overlying atmosphere, and the gas exchange coefficient (expressed in terms of the piston velocity) has been estimated on the basis of the vertical distribution of radon-222 gas in the upper 200 meters of water column. The net CO/sub 2/ flux across the air-sea interface has been computed using these two quantities. The areas north of the 10/sup 0/N parallel are a CO/sub 2/ sink area, where a net CO/sub 2/ flux ranging from 0 to about 1 mole CO/sub 2//m/sup 2/ y (from air to sea) has been observed. This compares with the global mean net CO/sub 2/ flux of about 0.6 mole CO/sub 2//m/sup 2/ y (from air to sea). On the other hand, the areas south of 10/sup 0/N are a CO/sub 2/ source area. The sea-to-air net flux of as high as 3 moles CO/sub 2//m/sup 2/ y has been observed east of the mouth of the Amazon River. Although the equatorial surface water exhibited high pCO/sub 2/ values, the gas exchange piston velocity was small particularly in the doldrum, and hence the net CO/sub 2/ flux values ranging between 1 and 2 moles CO/sub 2//m/sup 2/ y were observed.

  14. Water Dynamics at Protein-Protein Interfaces: Molecular Dynamics Study of Virus-Host Receptor Complexes.

    PubMed

    Dutta, Priyanka; Botlani, Mohsen; Varma, Sameer

    2014-12-26

    The dynamical properties of water at protein-water interfaces are unlike those in the bulk. Here we utilize molecular dynamics simulations to study water dynamics in interstitial regions between two proteins. We consider two natural protein-protein complexes, one in which the Nipah virus G protein binds to cellular ephrin B2 and the other in which the same G protein binds to ephrin B3. While the two complexes are structurally similar, the two ephrins share only a modest sequence identity of ∼50%. X-ray crystallography also suggests that these interfaces are fairly extensive and contain exceptionally large amounts of waters. We find that while the interstitial waters tend to occupy crystallographic sites, almost all waters exhibit residence times of less than hundred picoseconds in the interstitial region. We also find that while the differences in the sequence of the two ephrins result in quantitative differences in the dynamics of interstitial waters, the trends in the shifts with respect to bulk values are similar. Despite the high wetness of the protein-protein interfaces, the dynamics of interstitial waters are considerably slower compared to the bulk-the interstitial waters diffuse an order of magnitude slower and have 2-3 fold longer hydrogen bond lifetimes and 2-1000 fold slower dipole relaxation rates. To understand the role of interstitial waters, we examine how implicit solvent models compare against explicit solvent models in producing ephrin-induced shifts in the G conformational density. Ephrin-induced shifts in the G conformational density are critical to the allosteric activation of another viral protein that mediates fusion. We find that in comparison with the explicit solvent model, the implicit solvent model predicts a more compact G-B2 interface, presumably because of the absence of discrete waters at the G-B2 interface. Simultaneously, we find that the two models yield strikingly different induced changes in the G conformational density, even

  15. High Spatial Resolution Study of Microbe-Carbonate-Silicate Interfaces by FIB and TEM

    NASA Astrophysics Data System (ADS)

    Benzerara, K.; Menguy, N.; Guyot, F.; Vanni, C.; Gillet, P.

    2003-12-01

    High resolution transmission electron microscopy (HRTEM), chemical micro-analysis (EDX) and electron energy loss spectroscopy (EELS) are among the most powerful analytical techniques for studying microbe-mineral interactions, allowing to observe the microbe-mineral interface at almost the angstrom scale, to evidence transformations of the mineral structure and chemical alterations at the nanometer scale. However, the samples must be very thin and only a small area can be investigated. A key limitation for using this technique is thus to prepare natural geomicrobiological samples which combine hard minerals, preventing use of ultramicrotomy, with soft organic matter inadequate to ion milling procedures. Additionaly the areas of interest are usually restricted to few micrometer large areas which have to be selected from macroscopic samples. In this study we present two procedures : micromanipulation and FIB (Focused Ion Beam) which allow the study of microbe-mineral interfaces with TEM. The micromanipulation procedure has been presented in Benzerara et al (2003, PNAS). We have evidenced nannobacteria-like objects at the surface of the Tatahouine orthopyroxenite meteorite fallen in the tunisian desert in 1931. SEM observations suggest a complex interaction pattern between the nannobacteria-like objects, the pyroxene and microorganisms which have colonized the surface of the meteorite during its seventy years of residence on Earth. The TEM study on the very same area shows that the nannobacteria-like rods are actually well-crystallized nanometric calcite single crystals surrounded by an amorphous layer of carbonate composition. Those morphologies and structures are unusual for calcite single crystals. We discuss these observations in regard to the criteria of biogenicity i.e. biosignatures. Moreover, we examine the implications for carbonate production associated to silicate bio-weathering under aridic conditions. This work is relevant both to astrobiological and

  16. 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.

  17. 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(+).

  18. 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}

  19. European Contribution to Human Aspect Investigations for Future Planetary Habitat Definition Studies: Field Tests at MDRS on Crew Time Utilisation and Habitat Interfaces

    NASA Astrophysics Data System (ADS)

    Pletser, Vladimir; Foing, Bernard

    2011-02-01

    Human factors are a dominant aspect in space missions, which may strongly influence work results and efficiency. To assess their impact on future long term space missions and to attempt a general quantification, the environmental and technical conditions to which astronauts may be confronted need to be reproduced as closely as possible. Among the stressors that occur during space missions, limited resources, limited social interactions, long term living and working in confined and isolated areas are among the most important for future planetary exploration. The European Space Agency (ESA) has a strong interest in obtaining data and insights in human aspects to prepare for future studies on the definition of future Lunar and Martian planetary habitats. In this frame, ESA's Directorate of Human Space Flight was associated to the EuroGeoMars campaign conducted by the Crews 76 and 77 in February 2009 in The Mars Society's `Mars Desert Research Station' (MDRS) in the Desert of Utah. The EuroGeoMars Campaign lasted 5 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 (1) crew time organization in a planetary habitat, (2) an evaluation of the different functions and interfaces of this habitat, (3) an evaluation of man-machine interfaces of science and technical equipment. Several forms and questionnaires were filled in by all crew members: time and location evaluation sheets and two series of questionnaires. In addition, the crew participated in another on-going food study where the type of food was imposed and crew impressions were collected via questionnaires. The paper recalls the objectives of the human crew related experiments of the EuroGeoMars project and presents the first results of these field investigations. Some recommendations and lessons learnt will be presented and used as first inputs for future planetary habitat

  20. 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

  1. 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.

  2. Computational parametric study of a Richtmyer-Meshkov instability for an inclined interface.

    PubMed

    McFarland, Jacob A; Greenough, Jeffrey A; Ranjan, Devesh

    2011-08-01

    A computational study of the Richtmyer-Meshkov instability for an inclined interface is presented. The study covers experiments to be performed in the Texas A&M University inclined shock tube facility. Incident shock wave Mach numbers from 1.2 to 2.5, inclination angles from 30° to 60°, and gas pair Atwood numbers of ∼0.67 and ∼0.95 are used in this parametric study containing 15 unique combinations of these parameters. Qualitative results are examined through a time series of density plots for multiple combinations of these parameters, and the qualitative effects of each of the parameters are discussed. Pressure, density, and vorticity fields are presented in animations available online to supplement the discussion of the qualitative results. These density plots show the evolution of two main regions in the flow field: a mixing region containing driver and test gas that is dominated by large vortical structures, and a more homogeneous region of unmixed fluid which can separate away from the mixing region in some cases. The interface mixing width is determined for various combinations of the parameters listed at the beginning of the Abstract. A scaling method for the mixing width is proposed using the interface geometry and wave velocities calculated using one-dimensional gas dynamic equations. This model uses the transmitted wave velocity for the characteristic velocity and an initial offset time based on the travel time of strong reflected waves. It is compared to an adapted Richtmyer impulsive model scaling and shown to scale the initial mixing width growth rate more effectively for fixed Atwood number.

  3. The phase diagrams of a finite superlattice with disordered interface: A Monte Carlo study

    NASA Astrophysics Data System (ADS)

    Boughrara, M.; Kerouad, M.; Zaim, A.

    2009-06-01

    Monte Carlo Simulation (MCS) has been used to study critical and compensation behavior of a ferrimagnetic superlattice on a simple cubic lattice. The superlattice consists of k unit cells, where the unit cell contains L layers of spin -1/2 A atoms, L layers of spin -1 B atoms and a disordered interface in between that is characterized by a random arrangement of A and B atoms of ApB type and a negative A- B coupling. We investigate the finite and the infinite superlattices and we found that the existence and the number of the compensation points depend strongly on the thickness of the superlattice (number of unit cells).

  4. Interface behavior study of WC92-Co8 coating produced by electrospark deposition

    NASA Astrophysics Data System (ADS)

    Ruijun, Wang; Yiyu, Qian; Jun, Liu

    2005-02-01

    WC92-Co8 coating produced by electrospark deposition effectively improves the surface performance of the substrate. The behavior of the interface between the WC92-Co8 coating and the substrate is studied in this paper. The high-melting-point WC92-Co8 was deposited onto the surface of Ti alloy, and the coating was usually more than 50 μm thick. The surface of the coating is mainly composed of TiC and W 2C besides a small amount of W, and its micro hardness reaches HV1129. The coating dramatically improves the performance of the substrate.

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

    SciTech Connect

    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.

  6. Time resolved study of hydroxyl radical oxidation of oleic acid at the air-water interface

    NASA Astrophysics Data System (ADS)

    Zhang, Xinxing; Barraza, Kevin M.; Upton, Kathleen T.; Beauchamp, J. L.

    2017-09-01

    The ubiquity of oleic acid (OA) renders it a poster child for laboratory investigations of environmental oxidation chemistry. In the current study, mechanistic details of the oxidation of OA by hydroxyl radicals at the air-water interface are investigated using field-induced droplet ionization mass spectrometry (FIDI-MS). Products from OH oxidation of both unsaturated and saturated carbon atoms are identified, and mechanisms for both types of oxidation processes are proposed. Uptake of oxygen in the interfacial layer increases linearly with time, consistent with Langmuir-Hinshelwood reaction kinetics. These results provide fundamental knowledge relating to OH initiated degradation of fatty acids in atmospheric aerosols.

  7. 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

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

    DOE PAGES

    Metsanurk, E.; Tamm, A.; Caro, A.; ...

    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.

  9. 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.

  10. Study of interface influence on bending performance of CFRP with embedded optical fibers

    NASA Astrophysics Data System (ADS)

    Liu, Rong-mei; Liang, Da-kai

    2008-11-01

    Studies showed that the bending strength of composite would be affected by embedded optical fibers. Interface strength between the embedded optical fiber and the matrix was studied in this paper. Based on the single fiber pull out tests, the interfacial shear strength between the coating and the clad is the weakest. The shear strength of the optical fiber used in this study is near to 0.8MPa. In order to study the interfacial effect on bending property of generic smart structure, a quasi-isotropic composite laminates were produced from Toray T300C/ epoxy prepreg. Optical fibers were embedded within different orientation plies of the plates, with the optical fibers embedded in the same direction. Accordingly, five different types of plates were produced. Impact tests were carried out on the 5 different plate types. It is shown that when the fiber was embedded at the upper layer, the bending strength drops mostly. The bending normal stress on material arrives at the maximum. So does the normal stress applied on the optical fiber at the surface. Therefore, destructions could originate at the interface between the coating and the clad foremost. The ultimate strength of the smart structure will be affected furthest.

  11. Learning health ‘safety’ within non-technical skills interprofessional simulation education: a qualitative study

    PubMed Central

    Gordon, Morris; Fell, Christopher W. R.; Box, Helen; Farrell, Michael; Stewart, Alison

    2017-01-01

    ABSTRACT Background: Healthcare increasingly recognises and focusses on the phenomena of ‘safe practice’ and ‘patient safety.’ Success with non-technical skills (NTS) training in other industries has led to widespread transposition to healthcare education, with communication and teamwork skills central to NTS frameworks. Objective: This study set out to identify how the context of interprofessional simulation learning influences NTS acquisition and development of ‘safety’ amongst learners. Methods: Participants receiving a non-technical skills (NTS) safety focussed training package were invited to take part in a focus group interview which set out to explore communication, teamwork, and the phenomenon of safety in the context of the learning experiences they had within the training programme. The analysis was aligned with a constructivist paradigm and took an interactive methodological approach. The analysis proceeded through three stages, consisting of open, axial, and selective coding, with constant comparisons taking place throughout each phase. Each stage provided categories that could be used to explore the themes of the data. Additionally, to ensure thematic saturation, transcripts of observed simulated learning encounters were then analysed. Results: Six themes were established at the axial coding level, i.e., analytical skills, personal behaviours, communication, teamwork, context, and pedagogy. Underlying these themes, two principal concepts emerged, namely: intergroup contact anxiety – as both a result of and determinant of communication – and teamwork, both of which must be considered in relation to context. These concepts have subsequently been used to propose a framework for NTS learning. Conclusions: This study highlights the role of intergroup contact anxiety and teamwork as factors in NTS behaviour and its dissipation through interprofessional simulation learning. Therefore, this should be a key consideration in NTS education. Future

  12. In vitro study of the biological interface of Bio-Oss: implications of the experimental setup.

    PubMed

    Mladenović, Živko; Sahlin-Platt, Annika; Andersson, Britta; Johansson, Anders; Björn, Erik; Ransjö, Maria

    2013-03-01

    To systematically investigate the biological interface of Bio-Oss by analysing dissolution-precipitation behaviour and osteogenic responses using in vitro experimental systems. Different concentrations (1-100 mg/ml) of Bio-Oss were incubated in cell culture medium for 24 h before elemental concentrations for calcium, phosphorus and silicon in the medium were analysed with inductive coupled plasma-optical emission spectroscopy. Radioactive calcium-45 isotope labelling technique was used to study possible precipitation of calcium on the Bio-Oss particle. Biological interface of Bio-Oss was studied in osteogenic experiments using mineralization medium and three different sources of cells (primary mouse bone marrow stromal cells, primary rat calvarial cells and MC3T3-E1 mouse pre-osteoblast cell line). Cells were fixed and stained with Toulidine blue, von Kossa or Alizarin Red staining for confirmation of extracellular matrix mineralization. Elemental analysis of the cell culture medium demonstrated a significant decrease of calcium and phosphorus and a dose-dependent release of silicon to the medium after incubation with Bio-Oss. A significant decrease of calcium and phosphorus in the medium occurred even at low concentrations of Bio-Oss. Uptake of calcium on the Bio-Oss particle was confirmed with radioactive calcium-45 isotope labelling technique. In osteogenic experiments with Bio-Oss (<1 mg/ml), matrix mineralization around the Bio-Oss particles were demonstrated in all three cell types with von Kossa and Alizarin Red staining. Dissolution-precipitation reactions occur at the surface of Bio-Oss, and osteogenic responses are seen at the biological interface. The concentration of Bio-Oss is a key factor for the experimental in vitro results, and may also have implications for the clinic. © 2011 John Wiley & Sons A/S.

  13. 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.

  14. A study of technical signs in science: implications for lexical database development.

    PubMed

    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 found to be essential for the identification of signs appropriate for instruction. The results of this study also indicate a need for a systematic approach to examine both sign selection and its impact on learning by deaf students. Recommendations are made for the development of lexical databases and areas of research for optimizing the use of sign language in instruction.

  15. A versatile instrument for structural studies of interfaces in ultrahigh vacuum (abstract)

    NASA Astrophysics Data System (ADS)

    Clausnitzer, M.; Pauly, T.; Materlik, G.

    1989-07-01

    Structural studies of interfaces with synchrotron x-radiation (SXR) are presently carried out with several different methods which were developed in connection with SXR over the past decade: dynamical x-ray diffraction using standing wavefields (XSW), kinematical surface diffraction (KSD), Fresnel reflection (FR), and absorption spectroscopy (SEXAFS, SXANES). These methods can determine different, and often complementary parameters of a system such as short-/long-range order, relaxation relative to bulk, structure normal/parallel to surface, valence state of surface atoms, roughness of a buried interface, etc. Accordingly, these different principles have also been combined to form new methods such as diffraction of evanescent x rays during total external reflection (DEXTER) and reflection EXAFS (REFLEXAFS). It is, therefore, highly desirable to have the opportunity to study the same interface system with different methods. On the other hand, preparation of a system in ultrahigh vacuum requires in most cases expensive bulky equipment and time consuming techniques. These considerations call for a setup which provides different experimental options. We have, therefore, installed at the beamline ROEMO I at HASYLAB a versatile UHV system for interface studies. A sample can either be prepared inside a chamber with three Knudsen cells for MBE growth and standard equipment for cleaning, heating and surface characterization by RHEED, or inside a chamber for aggressive gases. The first one is installed outside the interlock area providing access also when the ROEMO beam is on and the second one inside the interlock area. From either chamber the sample can be transferred into an analysis chamber at the ROEMO I station or into a transportable baby chamber. The analysis chamber can be used for measurements with standing waves, absorption spectroscopy and reflectivity measurements. Electrons are detected with a spherical analyzer and photons outside the vacuum through Be windows

  16. Interface pressure mapping pilot study to select surfaces that effectively redistribute pediatric occipital pressure.

    PubMed

    Higer, Samantha; James, Thomas

    2016-02-01

    The aim of this pilot study was to better inform clinical decisions to prevent pediatric occipital pressure ulcers with quantitative data to choose an appropriate reactive support surface. A commercially available capacitive pressure mapping system (XSENSOR, X3 Medical Seat System, Calgary, Canada) was used to evaluate a standard pediatric mattress and four commercially available pressure-redistributing support surfaces. The pressure mapping system was validated for use in the pediatric population through studies on sensitivity, accuracy, creep, and repeatability. Then, a pilot pressure mapping study on healthy children under 6 years old (n = 22) was performed to determine interface pressure and pressure distribution between the occipital region of the skull and each surface: standard mattress, gel, foam, air and fluidized. The sensor was adequate to measure pressure generated by pediatric occipital loading, with 0.5-9% error in accuracy in the 25-95 mmHg range. The air surface had the lowest mean interface pressure (p < .005) and lowest peak pressure index (PPI), defined as the peak pressure averaged over four sensels, (p < .005). Mean interface pressure for mattress, foam, fluidized, gel, and air materials were 24.8 ± 4.42, 24.1 ± 1.89, 19.4 ± 3.25, 17.9 ± 3.10, and 14.2 ± 1.41 mmHg, respectively. The air surface also had the most homogenous pressure distribution, with the highest mean to PPI ratio (p < .005) and relatively high contact area compared to the other surfaces (p < .005). The air surface was the most effective pressure-redistributing material for pediatric occipital pressure as it had the lowest interface pressure and a homogeneous pressure distribution. This implies effective envelopment of the bony prominence of the occiput and increasing contact area to decrease peak pressure points. Copyright © 2015 Tissue Viability Society. Published by Elsevier Ltd. All rights reserved.

  17. 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.

  18. Synchrotron X-ray scattering studies of nanostructure-formation at interfaces

    NASA Astrophysics Data System (ADS)

    Sanyal, Milan K.

    2013-02-01

    We shall discuss results of a series of synchrotron x-ray scattering studies to understand the ordering of nanostructured materials formed at interfaces. In particular we shall discuss formation of germanium quantum-dots at the MBE grown silicon-germanium super-lattice structure and reversible crystallization of monolayer of Polyhedral Oligomeric SilSesquioxane (POSS) on water surface. The consistent analysis of the x-ray reflectivity and diffraction data collected in the Indian Beamline at Photon Factory Synchrotron, KEK, Japan have allowed determination of electron density and strain profile as a function of depth. The electron density profile obtained from the reflectivity and elemental profile obtained from SIMS measurements were effectively used to calculate diffraction data that provided strain and compositional profiles. The behaviour of amphiphilic Silsesquioxane POSS molecules under in-plane pressure in a Langmuir trough was studied at the ChemMatCARS, Sector 15, Advanced Photon Source, USA. We observe clear evidence of reversible crystallization of the POSS monolayers at the air-water interface - at higher pressure sharp diffraction spots are observed and as the pressure is withdrawn typical monolayer scattering comes back. Results of AFM studies of the lifted films in these two extreme phases were found to be consistent with the x-ray data.

  19. A fundamental study of the manganese dioxide-graphitic carbon interface

    NASA Astrophysics Data System (ADS)

    Corso, Brad L.

    Graphitic carbons are ubiquitous in electrochemical applications because of their high conductivity and chemical inertness under harsh electrochemical conditions. For pseudocapacitors, the graphitic carbon often acts merely as a supporting, conductive substrate or additive for a pseudocapacitive transition metal oxide to achieve a high energy and power density. However, for thick metal oxide films the power can still be limited by ionic diffusion through the pores, low conductivity in the metal oxide itself, or slow electron transfer across the heterogeneous interface. Nanostructures overcome the first two of these power limitations because intrinsic nano-scale diffusion lengths make ionic diffusion and metal oxide resistance negligible. However, nano-scale thickness of the metal oxide does not improve the poor electron transfer at the graphitic carbon / metal oxide interface. Harsh oxidation (activation) of the graphitic carbon before depositing the metal oxide layer has been shown to improve the electrochemical performance of pseudocapacitors in bulk due to the electron transfer enhancing properties of the induced defects; however, little is known about the contributions of any single defect type because of the difficulty in precisely controlling the oxidation. In this paper an individual single-walled carbon nanotube (SWNT) - Manganese Oxide (MnO 2) nanostructure is used to study the graphitic carbon / metal oxide interface. An individual SWNT gives precise control of sidewall defects, and provides an opportunity to study a pristine and single-defect interface. This paper reports only on a pristine SWNT-MnO2 interface. First, a pulsed deposition method is demonstrated; it consists of a single nucleation pulse and multiple deposition pulses that give a conformal coating of MnO 2 on the pristine sidewall of the SWNT. These films have a minimum thickness of 10-40 nm, dependent on the duration of the nucleation pulse (10-100 ms), and they show a linear dependence in

  20. 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.