Science.gov

Sample records for interface studies technical

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

    NASA Technical Reports Server (NTRS)

    1976-01-01

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

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

    NASA Technical Reports Server (NTRS)

    1976-01-01

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

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

    SciTech Connect

    Not Available

    1992-12-31

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

  4. 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.

  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. 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.

  8. 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.

  9. 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…

  10. 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.

  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. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

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

    PubMed

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

    2012-10-28

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

  1. 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…

  2. 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

  3. 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.

  4. '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.…

  5. 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…

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

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

    SciTech Connect

    O`Hara, J.M.

    1994-07-01

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

  14. 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

  15. 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.

  16. 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.

  17. [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).

  18. 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

  19. 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…

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Space Weather Studies at Istanbul Technical University

    NASA Astrophysics Data System (ADS)

    Kaymaz, Zerefsan

    2016-07-01

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

  5. 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.

  6. 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.

  7. 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.

  8. 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…

  9. 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.

  10. 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.

  11. 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…

  12. 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

  13. 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.

  14. 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.

  15. 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…

  16. 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…

  17. 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…

  18. 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.

  19. 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.

  20. 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.

  1. 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.…

  2. 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…

  3. 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.

  4. 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.

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

    DTIC Science & Technology

    1983-09-08

    Electronic Properties of the Si-Cr Interface," Phys. Rev. B 25, 4981-4993 (1982). - Y. Chahal, A. Franciosi, 3.1. Weaver, .1.E. Rove, and J.M. Posts...846 (1983). - A. Franciosi, D.C. OoNeill, and 3.31. Weaver, "Modulation of the Morphology and Electronic Properties of the Si(Ill)-Au Interface,* J...Vac. Sdi. Technol. 19 657-660 (1981)A9 - A. Franciosi, 0.3. Peteruan, J.H. Weaver, and V.L. Moruzzi, "Structural Morphology and Electronic Properties

  7. 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.

  8. 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.).

  9. 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.

  10. 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.

  11. 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.

  12. 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

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

    ERIC Educational Resources Information Center

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

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

  14. 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.

  15. 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.

  16. 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.

  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. 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…

  19. Si nanocrystals and nanocrystal interfaces studied by positron annihilation

    NASA Astrophysics Data System (ADS)

    Kujala, J.; Slotte, J.; Tuomisto, F.; Hiller, D.; Zacharias, M.

    2016-10-01

    Si nanocrystals embedded in a SiO 2 matrix were studied with positron annihilation and photoluminescence spectroscopies. Analysis of the S- and W-parameters for the sample annealed at 800 °C reveals a positron trap at the interface between the amorphous nanodots and the surrounding matrix. Another trap state is observed in the 1150 °C heat treated samples where nanodots are in a crystalline form. Positrons are most likely trapped to defects related to dangling bonds at the surface of the nanocrystals. Passivation of the samples results on one hand in the decrease of the S-parameter implying a decrease in the open volume of the interface state and, on the other hand, in the strengthening of the positron annihilation signal from the interface. The intensity of the photoluminescence signal increases with the formation of the nanocrystals. Passivation of samples strengthens the photoluminescence signal, further indicating a successful deactivation of luminescence quenching at the nanocrystal surface. Strengthening of the positron annihilation signal and an increase in the photoluminescence intensity in passivated silicon nanocrystals suggests that the positron trap at the interface does not contribute to a significant extent to the exciton recombination in the nanocrystals.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Space systems environmental interaction studies. Technical report

    SciTech Connect

    Morgan, M.A.; Huber, A.C.; McGarity, J.O.; Sperry, D.J.; Moran, S.J.

    1993-01-12

    A significant level of effort was expended during the report period, on Task 1 ( the Photovoltaic Array Space Power Plus Diagnostics PASP Plus experiment), and on Task 3 (the Space Wave Interactions with Plasmas Experiment SWIPE). A somewhat lower level of effort went into Task 2, the Charging Hazards and Wake Studies CHAWS program. Under Task 1, the APEX system, environmental and comprehensive performance tests were supported. In addition, the hardware and software design for the Ground Support Equipment (GSE) to support launch and on-orbit operations was finalized, assembled, tested and shipped to the satellite control center. On Task 3, hardware was designed and built for the upcoming SWIPE mission on the OEDIPUS-C rocket launch. A good deal of time went into writing instrument software as well. This work is still on-going. Task 2 efforts dealt largely with designing and procuring a state-of-the-art anode array for an enhanced capability instrument, to be used on a future flight opportunity.

  6. 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.

  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. 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.

  10. 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…

  11. 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…

  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. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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

  1. 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).

  2. 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.

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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…

  14. 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.

  15. 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.

  16. 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,…

  17. 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.

  18. 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).

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. 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…

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  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. 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.

  12. 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...

  13. 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.

  14. 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.

  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. 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.

  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. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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,…

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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…

  12. 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,

  13. 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.

  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. 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.

  17. 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.

  18. 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.

  19. 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…

  20. 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)…

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. [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.

  10. 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

  11. 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.

  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. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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…

  1. 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.

  2. 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

  3. 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

  4. 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.

  5. 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.

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

    NASA Technical Reports Server (NTRS)

    1972-01-01

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

  7. 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:…

  8. 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.

  9. 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.

  10. 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.

  11. 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.

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

    PubMed Central

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

    2016-01-01

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

  13. 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

  14. 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).

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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…

  20. 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.

  1. 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.

  2. 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…

  3. 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…

  4. 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…

  5. 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),…

  6. 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.

  7. 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.

  8. 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.

  9. 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…

  10. 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.…

  11. 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.

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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…

  17. 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)

  18. 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…

  19. 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.…

  20. 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…

  1. 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…

  2. 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.

  3. 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

  4. 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

  5. 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.

  6. 29 CFR 1607.14 - Technical standards for validity studies.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... determination of the number of persons necessary to permit the conduct of a meaningful criterion-related study.... These guidelines do not require a user to hire or promote persons for the purpose of making it possible... view of the possibility of bias in subjective evaluations, supervisory rating techniques...

  7. 29 CFR 1607.14 - Technical standards for validity studies.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... determination of the number of persons necessary to permit the conduct of a meaningful criterion-related study.... These guidelines do not require a user to hire or promote persons for the purpose of making it possible... view of the possibility of bias in subjective evaluations, supervisory rating techniques...

  8. 29 CFR 1607.14 - Technical standards for validity studies.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... determination of the number of persons necessary to permit the conduct of a meaningful criterion-related study.... These guidelines do not require a user to hire or promote persons for the purpose of making it possible... view of the possibility of bias in subjective evaluations, supervisory rating techniques...

  9. 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:…

  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. 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).

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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…

  9. 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…

  10. 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…

  11. 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)

  12. 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.…

  13. 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…

  14. 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…

  15. 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…

  16. 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…

  17. 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'…

  18. 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,…

  19. 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…

  20. 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,…

  1. 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.

  2. 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…

  3. 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.

  4. 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.

  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. 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.

  7. 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…

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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…

  2. 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…

  3. 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…

  4. 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.

  5. 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.

  6. 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).

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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

  18. 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.

  19. 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

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. 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…

  5. 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…

  6. 1991 Pacific Northwest Loads and Resources Study, Technical Appendix: Volume 1.

    SciTech Connect

    United States. Bonneville Power Administration.

    1992-03-01

    This publication provides detailed documentation of the load forecast scenarios and assumptions used in preparing BPA's 1991 Pacific Northwest Loads and Resources Study (the Study). This is one of two technical appendices to the Study; the other appendix details the utility-specific loads and resources used in the Study. The load forecasts and assumption were developed jointly by Bonneville Power Administration (BPA) and Northwest Power Planning Council (Council) staff. This forecast is also used in the Council's 1991 Northwest Conservation and Electric Power Plan (1991 Plan).

  7. 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}

  8. 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…

  9. 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.

  10. 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.

  11. 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(+).

  12. 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.

  13. 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

  14. 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).

  15. 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.

  16. 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.

  17. 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

  18. 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…

  19. 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.

  20. 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

  1. 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

  2. Linear and nonlinear impedance spectroscopy for the study of electrode/solution interfaces

    NASA Astrophysics Data System (ADS)

    Peck, John R.

    We develop and demonstrate techniques to produce stable, electrically nonlinear conditions at electrode/solution interfaces in the absence of charge-transfer (faradaic) reactions for application to electrochemical biosensors. We introduce random-pulse AC voltammetry for the study of interfacial nonlinearities, and apply the technique to studies of pH-active self-assembled monolayers (SAMs). These studies show that interfacial nonlinearities can be an order of magnitude more sensitive to the charge state of the surface than its linear properties. Furthermore, the use of these nonlinearities will allow isolation of the interface from a linear background due to fixture or equipment parasitics---a background that becomes severe as electrode sizes shrink for microarray applications. We make arguments for the use of radio frequencies in these systems, and present techniques to extend the use of conventional electrochemical equipment to these frequencies. Finally, we simulate the use of a slot antenna resonator for the detection of DNA hybridization at GHz frequencies, and find that shifts in the system resonances upon hybridization should be easily seen if the high frequency fields are confined to the surface region.

  3. 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.

  4. 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

  5. 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.

  6. Negative Feedback for Small Capacitive Touchscreen Interfaces: A Usability Study for Data Entry Tasks.

    PubMed

    Parikh, S P; Esposito, J M

    2012-01-01

    Touchscreen technology has become pervasive in the consumer product arena over the last decade, offering some distinct advantages such as software reconfigurable interfaces and the removal of space consuming mice and keyboards. However, there are significant drawbacks to these devices that have limited their adoption by some users. Most notably, standard touchscreens demand the user's visual attention and require them to look at the input device to avoid pressing the wrong button. This issue is particularly important for mobile, capacitive sensing, nonstylus devices, such as the iPhone where small button sizes can generate high error rates. While previous work has shown the benefits of augmenting such interfaces with audio or vibrotactile feedback, only positive feedback (confirmation of button presses) has been considered. In this paper, we present a simple prototype interface that provides negative vibrotactile feedback. By negative, we mean feedback is generated when an inactive or ambiguous part of the screen, such as the area between two buttons, is touched. First, we present a usability study comparing positive and negative vibrotactile feedback for a benchmark numerical data entry task. The difference in performance is not statistically significant, implying negative feedback provides comparable benefits. Next, based on the experimenter's observations and the users comments, we introduce a multimodal feedback strategy-combining complementary positive audio and negative vibrotactile signals. User tests on a text entry experiment show that, with multimodal feedback, users exhibit a (statistically significant) 24 percent reduction in corrective key presses, as compared to positive audio feedback alone. Exit survey comments indicate that users favor multimodal feedback.

  7. Study of the low-pressure chemical-vapor-deposited tungsten-silicon interface: Interfacial fluorine

    SciTech Connect

    Carlisle, J.A.; Chopra, D.R.; Dillingham, T.R.; Gnade, B.; Smith, G.

    1989-03-15

    Single-crystal silicon <100> substrates uniformly doped at approx. >12 ..cap omega.. cm with boron were deposited with approx.800 A of low-pressure chemically vapor deposited W in a hot-quartz-walled (Anicon) system at a deposition temperature of 300 /sup 0/C. The samples studied include an as-deposited sample and two others which were post-deposition annealed at 600 /sup 0/C in Ar for 15 min each. X-ray photoelectron spectroscopy (XPS) coupled with an Ar/sup +/ ion sputter profiling technique was employed to investigate these structures as a function of depth. Particular emphasis was placed on the depth distribution, content, and chemical state of the fluorine present. Rutherford backscattering spectrometry and x-ray diffraction were used to corroborate the XPS data. Results show that, for the as-deposited and 600 /sup 0/C annealed sample, the maximum concentration of fluorine (0.6--0.8 at. %) is observed, not at the W/Si interface, but rather at the W (H/sub 2/ reduction)/W (Si displacement) interface. For the sample annealed at 850 /sup 0/C, WSi/sub 2/ is formed in the overlayer, and the peak in the F profile corresponds to the position of the WSi/sub 2//Si interface. The maximum concentration of fluorine is reduced by approximately 75% to 0.23 at. % in this sample. From the XPS spectra of the F 1s region, the chemical species of fluorine present in these samples have been identified as WF/sub 6/, WF/sub 5/, and WF/sub 4/.

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    1985-04-01

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

  10. A Practical Study on the Design of a User-Interface Robot Application

    NASA Astrophysics Data System (ADS)

    Saerbeck, Martin; Bleuzé, Benoît; van Breemen, Albert

    People are striving for easy, natural interfaces. Robotic user interfaces aim at providing this kind of interface by using human like interaction modalities. However, many applications fail, not because of fundamental problems of addressing social interaction but due to an unbalanced design. In this paper we derive a balancing framework for designing robotic user interfaces that balances four key dimensions: user, application, interface and technology. We investigate applicability of the the framework by means of two experiments. The first experiment demonstrates that violations to the balancing framework can negate the efforts to improve an interface with natural interaction modalities. In the second experiment we present a real world application that adheres to the balancing concepts. Our results show that a balanced design is a key factor for the success or failure of a given robotic interface.

  11. 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.

  12. 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

  13. 1994 Pacific Northwest Loads and Resources Study, Technical Appendix: Volume 1.

    SciTech Connect

    United States. Bonneville Power Administration.

    1994-12-01

    The 1994 Pacific Northwest Loads and Resources Study establishes the Bonneville Power Administration`s (BPA) planning basis for supplying electricity t6 BPA customers. The Loads and Resources Study is presented in two documents: (1) this technical appendix detailing loads and resources for each major Pacific Northwest generating utility; and (2) a summary of Federal system and Pacific Northwest region loads and resources. This analysis updates the 1993 Pacific Northwest Loads and Resources Study Technical Appendix published in December 1993. This technical appendix provides utility specific information that BPA uses in its long-range planning. It incorporates the following for each utility: (1) electrical demand-firm loads; (2) generating resources; and (3) contracts both inside and outside the region. This document should be used in combination with the 1994 Pacific Northwest Loads and Resources Study, published in December 1994, because much of the information in that document is not duplicated here. This BPA planning document incorporates Pacific Northwest generating resources and the 1994 medium load forecast prepared by BPA. Each utility`s forecasted future firm loads are subtracted from its existing resources to determine whether it will be surplus or deficit. If a utility`s resources are greater than loads in any particular year or month, there is a surplus of energy and/or capacity, which the utility can sell to increase revenues. Conversely, if its firm loads exceed available resources, there is a deficit of energy and/or capacity, and additional conservation, contract purchases, or generating resources will be needed to meet the utility`s load.

  14. Experimental studies of metal/InP interfaces formed at room temperature and 77K

    NASA Astrophysics Data System (ADS)

    He, L.; Shi, Z. Q.; Anderson, W. A.

    1994-12-01

    Metal/InP interfaces were formed at room temperature (RT = 300K) and low temperature (LT = 77K). A high leakage current was observed for the RT processed metal/InP samples due to its low barrier height (0.35 0.55 eV). An extremely low leakage current and high barrier height (up to 0.96 eV) were achieved when Au and Pd Schottky contacts to n-InP were produced at low temperature. Photoluminescence spectroscopy, Auger electron spectroscopy (AES), electron spectroscopy for chemical analysis (ESCA), and secondary ion mass spectroscopy (SIMS) were used to study the metal/InP interfaces. Photoluminescence spectra showed that there was less surface state density in LT samples. The RT processed sample showed more O and C in the surface region of an Au/InP structure than the same sample processed at LT in the AES spectra. The phosphide out-diffusion was observed in RT processed samples by ESCA. A possible P:O layer on the metal side of the LT processed sample was found by SIMS. Extensive chemical and structural analysis indicated that LT process caused the metal film to be continuous at 50 Å, much better than in standard RT processing.

  15. Adsorption of cationic polyacrylamide at the cellulose-liquid interface: a neutron reflectometry study.

    PubMed

    Su, Jielong; Garvey, Christopher J; Holt, Stephen; Tabor, Rico F; Winther-Jensen, Bjorn; Batchelor, Warren; Garnier, Gil

    2015-06-15

    The layer thickness and density of high molecular weight cationic polyacrylamide (CPAM) adsorbed at the cellulose-water interface was quantified by neutron reflectometry. The thickness of a full monolayer of CPAM of constant molecular weight (13 MD) but different charge densities, adsorbed with or without NaCl (10(-3) M), was studied. Thin cellulose films (40±7 Å) of roughness <10 Å were produced by spin coating a cellulose acetate-acetone solution and regenerating by alkaline hydrolysis. Film smoothness was greatly improved by controlling the concentration of cellulose acetate (0.13 wt%) and the hydrolysis time in sodium methoxide. The adsorption thickness of CPAM (40% charge 13 MD) at the solid-D2O interface was 43±4 Å on cellulose and 13±2 Å on silicon, an order of magnitude smaller than the CPAM radius of gyration. At constant molecular weight, the thickness of the CPAM layer adsorbed on cellulose increases with polymer charge density (10±1 Å at 5%). Addition of 10(-3) M NaCl decreased the thickness of CPAM layer already adsorbed on cellulose. However, the adsorption layer on cellulose of a CPAM solution equilibrated in 10(-3) M NaCl is much thicker (89±11 Å for 40% CPAM). For high molecular weight CPAMs adsorbed from solution under constant conditions, the adsorption layer can be varied by 1 order of magnitude via control of the variables affecting electrostatic intra- and inter-polymer chain interactions.

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  17. Studies on behaviors of dipalmitoylposphatidylcholine and bilirubin in mixed monolayer at the air/water interface

    NASA Astrophysics Data System (ADS)

    Shen, Yuhua; Tang, Yufeng; Xie, Anjian; Zhu, Jinmiao; Li, Shikuo; Zhang, Yong

    2006-06-01

    Mixed monolayers of dipalmitoylposphatidylcholine (DPPC) and bilirubin (BR) were prepared on different subphases. The properties of DPPC/BR monolayer, such as collapse pressure ( πcoll), limiting area per molecule ( Alim), surface compressibility modulus, free energy (Δ Gmix) and excess free energy (Δ Gex), were investigated based on the analysis of the surface pressure-area isotherms on pure water. The results showed that DPPC and BR were miscible and formed non-ideal mixed monolayers at the air/water interface. With the molar fraction of BR ( XBR) increasing, the LE-LC coexistence region of DPPC monolayer was eliminated gradually. The DPPC/BR complex (M D-B) of 1:2 stoichiometry formed as a result of the strong hydrogen bonds between the polar groups of DPPC and BR. The studies of effects of pH values and calcium ions in subphase on the DPPC/BR monolayers showed that the mixed monolayer became expanded on alkali aqueous solution and on 1 mmol/L CaCl 2 aqueous solution. The orientation of DPPC and BR at air/water interface was also discussed.

  18. First-principles study of fcc-Ag/bcc-Fe interfaces

    NASA Astrophysics Data System (ADS)

    Lu, Song; Hu, Qing-Miao; Punkkinen, Marko P. J.; Johansson, Börje; Vitos, Levente

    2013-06-01

    Ab initio calculations are employed to determine the lower and upper bounds of the interfacial energy and work of separation of a fcc-Ag/bcc-Fe interface. The strain-free interfacial energy of the coherent interface is taken as the lower bound and the interfacial energy of the commensurate incoherent interface as the upper bound of the interfacial energy of a realistic semicoherent interface. The latter is estimated by applying an averaging scheme based on the interfacial energies obtained for the coherent interfaces. Similar calculations are performed for determining the bounds of the work of separation. We justify the use of the averaging scheme by carrying out large supercell calculations for a semicoherent interface. For a Fe(110)/Ag(111) semicoherent interface, we show that taking either Fe or Ag as the underlying lattice, our averaging scheme can yield a reasonable estimation of the work of separation of the semicoherent interface. However, when taking Ag as the underlying lattice, the averaged interfacial energy of the semicoherent interface is significantly underestimated due to the magnetism. The structure and magnetism at the coherent and semicoherent interfaces are discussed.

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

    SciTech Connect

    Perahia, Dvora

    2011-11-01

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

  20. Study of space utilization and technical approaches to heating in buildings with irregular occupancy. Final report. Volume 1

    SciTech Connect

    Not Available

    1984-05-01

    The study objective was to review, identify and recommend technical approaches to the heating of buildings with irregular occupancy including physiological and psychological parameters affecting comfort. Numerous optimal room treatments have been identified for each space type and climate zone.

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

    NASA Technical Reports Server (NTRS)

    Weber, Gary A.

    1991-01-01

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

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

    SciTech Connect

    Kerstein, Alan R.; Lignell, David O.; Gonzalez-Juez, Esteban Daniel

    2010-11-01

    The parameterization of the fluxes of heat and salt across double-diffusive interfaces is of interest in geophysics, astrophysics, and engineering. The present work is a parametric study of these fluxes using one-dimensional-turbulence (ODT) simulations. Its main distinction is that it considers a parameter space larger than previous studies. Specifically, this work considers the effect on the fluxes of the stability parameter R{sub {rho}}, Rayleigh number Ra, Prandtl number, Lewis number, and Richardson number. The ratio Ra/R{sub {rho}} is found to be a dominant parameter. Here Ra/R{sub {rho}} can be seen as a ratio of destabilizing and stabilizing effects. Trends predicted by the simulations are in good agreement with previous models and available measurements.

  3. 75 FR 71671 - Draft Report on the Technical Study of the Sofa Super Store Fire-South Carolina, June 18, 2007.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-24

    ... National Institute of Standards and Technology Draft Report on the Technical Study of the Sofa Super Store... and Technology (NIST) seeks public comments on the draft report of its Technical Study of the Sofa... fire growth and spread. NIST recently completed a draft report of their technical study and...

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

    PubMed Central

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

    2014-01-01

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

  5. Technical and Conceptual Considerations for Performing and Interpreting Functional MRI Studies in Awake Rats

    PubMed Central

    Febo, Marcelo

    2011-01-01

    Functional neuroimaging studies in rodents have the potential to provide insight into neurodevelopmental and psychiatric conditions. The strength of the technique lies in its non-invasive nature that can permit longitudinal functional studies in the same animal over its adult life. The relatively good spatial and temporal resolution and the ever-growing database on the biological and biophysical basis of the blood oxygen level dependent (BOLD) signal make it a unique technique in preclinical neuroscience research. Our laboratory has used imaging to investigate brain activation in awake rats following cocaine administration and during the presentation of lactation-associated sensory stimuli. Factors that deserve attention when planning functional magnetic resonance imaging studies in rats include technical issues, animal physiology and interpretability of the resulting data. The present review discusses the pros and cons of animal imaging with a particular focus on the technical aspects of studies with awake rats. Overall, the benefits of the technique outweigh its limitations and the rapidly evolving methods will open the way for more laboratories to employ the technique in neuroscience research. PMID:21808625

  6. Structuration in the Interface of Direct and Reversed Micelles of Sucrose Esters, Studied by Fluorescent Techniques

    PubMed Central

    Sandoval, Catalina; Ortega, Anakenna; Sanchez, Susana A.; Morales, Javier; Gunther, German

    2015-01-01

    Background Reactors found in nature can be described as micro-heterogeneous systems, where media involved in each micro-environment can behave in a markedly different way compared with the properties of the bulk solution. The presence of water molecules in micro-organized assemblies is of paramount importance for many chemical processes, ranging from biology to environmental science. Self-organized molecular assembled systems are frequently used to study dynamics of water molecules because are the simplest models mimicking biological membranes. The hydrogen bonds between sucrose and water molecules are described to be stronger (or more extensive) than the ones between water molecules themselves. In this work, we studied the capability of sucrose moiety, attached to alkyl chains of different length, as a surface blocking agent at the water-interface and we compared its properties with those of polyethylenglycol, a well-known agent used for this purposes. Published studies in this topic mainly refer to the micellization process and the stability of mixed surfactant systems using glycosides. We are interested in the effect induced by the presence of sucrose monoesters at the interface (direct and reverse micelles) and at the palisade (mixtures with Triton X-100). We believe that the different functional group (ester), the position of alkyl chain (6-O) and the huge capability of sucrose to interact with water will dramatically change the water structuration at the interface and at the palisade, generating new possibilities for technological applications of these systems. Results Our time resolved and steady state fluorescence experiments in pure SEs micelles show that sucrose moieties are able to interact with a high number of water molecules promoting water structuration and increased viscosity. These results also indicate that the barrier formed by sucrose moieties on the surface of pure micelles is more effective than the polyoxyethylene palisade of Triton X-100

  7. An optimization-based study of equivalent circuit models for representing recordings at the neuron-electrode interface.

    PubMed

    Thakore, V; Molnar, P; Hickman, J J

    2012-08-01

    Extracellular neuroelectronic interfacing is an emerging field with important applications in the fields of neural prosthetics, biological computation, and biosensors. Traditionally, neuron-electrode interfaces have been modeled as linear point or area contact equivalent circuits but it is now being increasingly realized that such models cannot explain the shapes and magnitudes of the observed extracellular signals. Here, results were compared and contrasted from an unprecedented optimization-based study of the point contact models for an extracellular "on-cell" neuron-patch electrode and a planar neuron-microelectrode interface. Concurrent electrophysiological recordings from a single neuron simultaneously interfaced to three distinct electrodes (intracellular, "on-cell" patch, and planar microelectrode) allowed novel insights into the mechanism of signal transduction at the neuron-electrode interface. After a systematic isolation of the nonlinear neuronal contribution to the extracellular signal, a consistent underestimation of the simulated suprathreshold extracellular signals compared to the experimentally recorded signals was observed. This conclusively demonstrated that the dynamics of the interfacial medium contribute nonlinearly to the process of signal transduction at the neuron-electrode interface. Further, an examination of the optimized model parameters for the experimental extracellular recordings from sub- and suprathreshold stimulations of the neuron-electrode junctions revealed that ionic transport at the "on-cell" neuron-patch electrode is dominated by diffusion whereas at the neuron-microelectrode interface the electric double layer (EDL) effects dominate. Based on this study, the limitations of the equivalent circuit models in their failure to account for the nonlinear EDL and ionic electrodiffusion effects occurring during signal transduction at the neuron-electrode interfaces are discussed.

  8. Earth Observatory Satellite system definition study. Report 2: Instrument constraints and interfaces

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The instrument constraints and interface specifications for the Earth Observatory Satellite (EOS) are discussed. The Land Use Classification Mission using a 7 band Thematic Mapper and a 4 band High Resolution Pointable Imager is stressed. The mission and performance of the instruments were reviewed and expanded to reflect the instrument as a part of the total remote sensing system. A preliminary EOS interface handbook is provided to describe the mission and system, to specify the spacecraft interfaces to potential instrument contractors, and to describe the instrument interface data required by the system integration contractor.

  9. Case study for the evaluation and selection of man-machine interface (MMI) software

    SciTech Connect

    Nekimken, H.; Pope, N.; Macdonald, J.; Bibeau, R.; Gomez, B.; Sellon, D.

    1996-06-01

    The authors evaluated three of the top man-machine interface (MMI) software systems. The main categories upon which they based their evaluation on were the following: operator interface; network and data distribution; input/output (I/O) interface; application development; alarms; real-time and historical trending; support, documentation, and training; processing tools (batch, recipe, logic); reports; custom interfacing; start-up/recovery; external database; and multimedia. They also present their MMI requirements and guidelines for the selection and evaluation of these MMI systems.

  10. Space shuttle/food system study. Volume 1: Technical volume, oven study

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The baseline space shuttle galley was designed to utilize lightweight rehydratable foods, to be prepared for consumption by rehydration with chilled or hot water. The impact is examined of an extension of food types to include thermostabilized food, at ambient temperature, and frozen foods on the baseline design of the shuttle galley. Weight, volume, and power penalities associated with heating thermostabilized and frozen foods by means of a hot air convection heating system and a conduction heating system are determined along with the impact on crew/galley interface and meal preparation.

  11. Neutron reflectivity studies on the DNA adsorption on lipid monolayers at the air liquid interface

    NASA Astrophysics Data System (ADS)

    Wu, Jui-Ching; Lin, Tsang-Lang; Jeng, U.-Ser; Torikai, Naoya

    2006-11-01

    In situ neutron reflectivity was used to study the DC-Chol and TC-Chol monolayers at the air-liquid interface in the presence and absence of DNA in the subphase. It was found that the DC-Chol is more effective in adsorbing the DNA than the TC-Chol. It was also found that a compact DNA layer formed beneath the DC-Chol monolayer with a DNA gap spacing around 20 Å and a less compact DNA layer adsorbed to the TC-Chol monolayer with a DNA spacing around 60 Å, as estimated from the determined neutron scattering length density. From the determined neutron scattering length density profiles, the adsorbed DNA somewhat penetrates into the head group region of the charged lipids.

  12. Moessbauer and adhesion study of ion beam-modified Fe-PTFE interfaces

    NASA Astrophysics Data System (ADS)

    Ingemarsson, P. Anders; Ericsson, Tore; Wappling, Roger; Possnert, Goran

    Conversion electron Moessbauer spectroscopy was used to study ion beam-induced effects at Fe-PTFE thin film interfaces and to relate these effects to accompanying modifications in adhesion. Irradiation with 16 MeV S-32(3+) ions to doses in the range between 5 x 10 to the 11th and 2 x 10 to the 14th ions/sq cm was carried out before or after deposition of thin Fe-57 layers. For both pre- and post-bombardment, a substantial adhesion enhancement was observed. Associated with this were significant changes in the Moessbauer spectra indicating the formation of Fe-C and Fe-F compounds. This compound formation can be associated with the observed improvement in thin film adhesion.

  13. Photoemission spectroscopy study of the lanthanum lutetium oxide/silicon interface

    SciTech Connect

    Nichau, A.; Schnee, M.; Schubert, J.; Bernardy, P.; Hollaender, B.; Buca, D.; Mantl, S.; Besmehn, A.; Breuer, U.; Rubio-Zuazo, J.; Castro, G. R.; Muecklich, A.; Borany, J. von

    2013-04-21

    Rare earth oxides are promising candidates for future integration into nano-electronics. A key property of these oxides is their ability to form silicates in order to replace the interfacial layer in Si-based complementary metal-oxide field effect transistors. In this work a detailed study of lanthanum lutetium oxide based gate stacks is presented. Special attention is given to the silicate formation at temperatures typical for CMOS processing. The experimental analysis is based on hard x-ray photoemission spectroscopy complemented by standard laboratory experiments as Rutherford backscattering spectrometry and high-resolution transmission electron microscopy. Homogenously distributed La silicate and Lu silicate at the Si interface are proven to form already during gate oxide deposition. During the thermal treatment Si atoms diffuse through the oxide layer towards the TiN metal gate. This mechanism is identified to be promoted via Lu-O bonds, whereby the diffusion of La was found to be less important.

  14. Photoemission study of the Cs$z.urule;GaP(110) interface at low temperatures

    NASA Astrophysics Data System (ADS)

    Chassé, Th.; Paggel, J.; Neuhold, G.; Theis, W.; Horn, K.

    1994-04-01

    The formation of the Cs⧸GaP(110) interface at low temperature has been studied using core and valence level photoemission. It is found that a nonmetallic first adsorption layer is followed by a transition to a metallic film. Valence level spectra show that Cs induces a new peak above the valence band maximum, which from the appearance of the core level spectra is assigned to adsorbate-substrate charge transfer. At higher coverages an intermediate species is identified on the basis of Cs 5p core level spectra. The metallic layer of Cs is characterised by metallic surface and bulk core level emission, the occurrence of plasmon satellites, and the emergence of a metallic Fermi edge. The relative separation of the different Cs core level line contributions are analysed through a Born-Haber cycle and qualitative arguments based on final state screening.

  15. Paired Associative Stimulation Using Brain-Computer Interfaces for Stroke Rehabilitation: A Pilot Study

    PubMed Central

    Cho, Woosang; Sabathiel, Nikolaus; Ortner, Rupert; Lechner, Alexander; Irimia, Danut C.; Allison, Brendan Z.; Edlinger, Guenter; Guger, Christoph

    2016-01-01

    Conventional therapies do not provide paralyzed patients with closed-loop sensorimotor integration for motor rehabilitation. Paired associative stimulation (PAS) uses brain-computer interface (BCI) technology to monitor patients’ movement imagery in real-time, and utilizes the information to control functional electrical stimulation (FES) and bar feedback for complete sensorimotor closed loop. To realize this approach, we introduce the recoveriX system, a hardware and software platform for PAS. After 10 sessions of recoveriX training, one stroke patient partially regained control of dorsiflexion in her paretic wrist. A controlled group study is planned with a new version of the recoveriX system, which will use a new FES system and an avatar instead of bar feedback. PMID:27990240

  16. [Study on the method of feature extraction for brain-computer interface using discriminative common vector].

    PubMed

    Wang, Jinjia; Hu, Bei

    2013-02-01

    Discriminative common vector (DCV) is an effective method that was proposed for the small sample size problems of face recognition. There is the same problem in brain-computer interface (BCI). Using directly the linear discriminative analysis (LDA) could result in errors because of the singularity of the within-class matrix of data. In our studies, we used the DCV method from the common vector theory in the within-class scatter matrix of data of all classes, and then applied eigenvalue decomposition to the common vectors to obtain the final projected vectors. Then we used kernel discriminative common vector (KDCV) with different kernel. Three data sets that include BCI Competition I data set, Competition II data set IV, and a data set collected by ourselves were used in the experiments. The experiment results of 93%, 77% and 97% showed that this feature extraction method could be used well in the classification of imagine data in BCI.

  17. Thermal study of interface between the Orbiter cold plate and typical Shuttle spacecraft payload flight electronics

    NASA Technical Reports Server (NTRS)

    Hwangbo, H.; Coyle, M. J.

    1979-01-01

    Spacelab provides a set of Freon line plumbing and cold plates for experiment equipments which are located in the Shuttle pallet and which need active thermal control. The reported study deals with the thermal problem of attaching a Command and Data Handling module with various electronic boxes whose combined footprints on the baseplate are much larger than the cold plate. A description of two modules and the cold plate assembly in the pallet is presented and a thermal model description is provided. The method employed in modeling heat pipes-honey-comb matrix is based upon an effective conductance between the heat pipe vapor and the walls of the heat pipe. The considered thermal models and a computer program are used to perform steady-state thermal analyses. The temperature gradients in the large module baseplate attached to the small cold plate are predicted as a function of the interface plate thickness.

  18. Paired Associative Stimulation Using Brain-Computer Interfaces for Stroke Rehabilitation: A Pilot Study.

    PubMed

    Cho, Woosang; Sabathiel, Nikolaus; Ortner, Rupert; Lechner, Alexander; Irimia, Danut C; Allison, Brendan Z; Edlinger, Guenter; Guger, Christoph

    2016-06-13

    Conventional therapies do not provide paralyzed patients with closed-loop sensorimotor integration for motor rehabilitation. Paired associative stimulation (PAS) uses brain-computer interface (BCI) technology to monitor patients' movement imagery in real-time, and utilizes the information to control functional electrical stimulation (FES) and bar feedback for complete sensorimotor closed loop. To realize this approach, we introduce the recoveriX system, a hardware and software platform for PAS. After 10 sessions of recoveriX training, one stroke patient partially regained control of dorsiflexion in her paretic wrist. A controlled group study is planned with a new version of the recoveriX system, which will use a new FES system and an avatar instead of bar feedback.

  19. Atomistic simulation study of linear alkylbenzene sulfonates at the water/air interface

    PubMed Central

    He, Xibing; Guvench, Olgun; MacKerell, Alexander D.; Klein, Michael L.

    2010-01-01

    Molecular Dynamics simulations with the CHARMM atomistic force field have been used to study monolayers of a series of linear alkylbenzene sulfonates (LAS) at the water/air interface. Both the numbers of carbon atoms in the LAS alkyl tail (1 to 11), and the position of attachment of the benzene ring on the alkyl chain have been varied. Totally 36 LAS homologues and isomers have been investigated. The surface tensions of the systems and the average tilt angles of the LAS molecules are found to be related to both the length and the degree of branching of the alkyl tails, whereas the solubility and mobility are mostly determined by the tail length. PMID:20614916

  20. Study of the electronic structure of the interfaces between 2-TNATA and MoOx.

    PubMed

    Lim, J T; Park, J W; Jhon, M S; Yeom, G Y

    2013-12-01

    In order to understand the characteristics of ohmic hole-contacts for the inverted/conventional organic light emitting devices, a hole-only device with all ohmic contacts, which is composed of glass/ITO/MoOx/4,4,4-tris[2-naphthyl-phenyl-amino]triphenylamine (2-TNATA)/MoOx/Al, the elements of the electronic structures of MoOx-on-2-TNATA interface and 2-TNATA-on-MoOx interface were investigated by photoemission spectroscopy, with regards to interface energetics, formative mechanism, and a potential charge carrier injection. The electronic structures revealed that the behavior of the interface between MoOx and 2-TNATA was different whether MoOx was deposited on (2-TNATA) or vice versa. The bottom interfaces of 2-TNATA-on-MoOx in this hole-only devices showed no hole-injecting barrier height (Phi(h)B) when the thickness of 2-TNATA was deposited in the range of 0.1 to 5.0 nm on the 10.0 nm-thick MoOx thin films. This has been explained to be attributed to both metal-induced gap states and a chemical reaction at the interfaces. The top interfaces of MoOx-on-2-TNATA in this hole-only device structure also showed no Phi(h)B when a hole was injected from the MoOx-on-2-TNATA interfaces to cathode. The hole-ohmic property in the top interfaces depends on interface dipole by the formation of charge transfer complexes as well as interdiffusion of MoOx into the 2-TNATA film in these interfaces.

  1. Computational Studies of [Bmim][PF6]/n-Alcohol Interfaces with Many-Body Potentials

    SciTech Connect

    Chang, Tsun-Mei; Dang, Liem X.

    2014-09-04

    In this paper, we present the results from molecular-dynamics simulations of the equilibrium properties of liquid/liquid interfaces of room temperature ionic liquid [bmim][PF6] and simple alcohols (i.e., methanol, 1-butanol, and 1-hexanol) at room temperature. Polarizable potential models are employed to describe the interactions among species. Results from our simulations show stable interfaces between the ionic liquid and n-alcohols, and we found that the interfacial widths decrease from methanol to 1-butanol systems, and then increase for 1-hexanol interfaces. Angular distribution analysis reveals that the interface induces a strong orientational order of [bmim] and n-alcohol molecules near the interface, with [bmim] extending its butyl group into the alcohol phase while the alcohol has the OH group pointing into the ion liquid region, which is consistent with the recent sum-frequency-generation experiments. We found the interface to have a significant influence on the dynamics of ionic liquids and n-alcohols. The orientational autocorrelation functions illustrate that [bmim] rotate more freely near the interface than in the bulk, while the rotation of n-alcohol is hindered at the interface. Additionally, the time scale associated with the diffusion along the interfacial direction is found to be faster for [bmim] but slowed down for n-alcohols approaching the interface. We also calculate the dipole moment of n-alcohols as a function of the distance normal to the interface. We found that, even though methanol and 1-butanol have different dipole moments in bulk phase, they reach a similar value at the interface. This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. Pacific Northwest National Laboratory is a multiprogram national laboratory operated for the Department of Energy by Battelle. The calculations were carried out using computer resources provided by the

  2. Study of interface state trap density on characteristics of MOS-HEMT

    NASA Astrophysics Data System (ADS)

    Tseng, Ming-Chun; Hung, Ming-Hsien; Wuu, Dong-Sing; Horng, Ray-Hua

    2015-03-01

    In this study, the effects of chemical treatment on the properties of MOS capacitors and metal-oxide-semiconductor high electron mobility transistor (MOS-HEMT) were studied. The structure consist of Al2O3/u-GaN/AlN buffer/ Si substrate and Al2O3 (10 nm)/u-AlGaN (25 nm)/u-GaN (2μm)/AlN buffer/Si substrate for MOS capacitor and MOS-HEMT device, respectively. There are four chemical treatment recipes, which consist of organic solvents, oxygen plasma, BCl3 plasma, dilute acidic solvent, hydrofluoric acid and RCA-like clean process to remove the metal ions, organic contamination and native oxide. Four different chemical treatment recipes treated the surface of u-GaN before Al2O3 was grown on the treated surface to reduce the interface state trap densities (Dit). The Dit value was calculated from measurement of C-V curve with 1M Hz frequency. The formation of interface state trap of u-GaN surface is modified by different chemical solution of varied chemical treatment recipe, which further influence the breakdown voltage (Vbk), on-resistance (Ron), threshold voltage (Vth) and drain current (Id) of MOS-HEMT. The Vth of MOS-HEMT with organic solvents clean treatment is -11.00V. The MOS-HEMT after BCl3 plasma and organic solvents clean treatment shows the lowest Vth of -9.55V. The electronic characteristics of MOS HEMT device with four different chemical treatment recipes were investigated in this article.

  3. Structural ordering at solid-liquid interfaces in Al-Sm system: A molecular-dynamics study

    DOE PAGES

    Sun, Yang; Zhang, Feng; Ye, Zhuo; ...

    2016-07-12

    The structural ordering at solid-liquid interfaces far from equilibrium is studied with molecular dynamics simulations for the Al-Sm system. Using the van-Hove self-correlation function as the criterion to identify attachment/detachment events that occur at the interface, we are able to determine the time-dependent interface position, and characterize the detailed interfacial structure ordering surrounding the attached atoms. For the interface between an undercooled Al90Sm10 liquid and a metastable cubic structure, the solid induces the crystalline order of the cubic phase in the liquid layers, promoting the continuous growth of the crystal phase. When the same liquid is put in contact withmore » f.c.c. Al, Sm from the liquid can still attach to the solid interface despite its insolubility in the Al lattice. Non-f.c.c. order is revealed surrounding the attached Sm atoms. Lastly, we show that the local structure ordering at interface is highly correlated to solid packing and liquid ordering.« less

  4. Structural ordering at solid-liquid interfaces in Al-Sm system: A molecular-dynamics study

    SciTech Connect

    Sun, Yang; Zhang, Feng; Ye, Zhuo; Ding, Zejun; Mendelev, Mikhail I.; Kramer, Matthew J.; Wang, Cai -Zhuang; Ho, Kai -Ming

    2016-07-12

    The structural ordering at solid-liquid interfaces far from equilibrium is studied with molecular dynamics simulations for the Al-Sm system. Using the van-Hove self-correlation function as the criterion to identify attachment/detachment events that occur at the interface, we are able to determine the time-dependent interface position, and characterize the detailed interfacial structure ordering surrounding the attached atoms. For the interface between an undercooled Al90Sm10 liquid and a metastable cubic structure, the solid induces the crystalline order of the cubic phase in the liquid layers, promoting the continuous growth of the crystal phase. When the same liquid is put in contact with f.c.c. Al, Sm from the liquid can still attach to the solid interface despite its insolubility in the Al lattice. Non-f.c.c. order is revealed surrounding the attached Sm atoms. Lastly, we show that the local structure ordering at interface is highly correlated to solid packing and liquid ordering.

  5. Correlates of non-technical skills in surgery: a prospective study

    PubMed Central

    Gillespie, Brigid M; Harbeck, Emma; Steel, Catherine; Fairweather, Nicole; Chaboyer, Wendy

    2017-01-01

    Background Communication and teamwork failures have frequently been identified as the root cause of adverse events and complications in surgery. Few studies have examined contextual factors that influence teams’ non-technical skills (NTS) in surgery. The purpose of this prospective study was to identify and describe correlates of NTS. Methods We assessed NTS of teams and professional role at 2 hospitals using the revised 23-item Non-TECHnical Skills (NOTECHS) and its subscales (communication, situational awareness, team skills, leadership and decision-making). Over 6 months, 2 trained observers evaluated teams’ NTS using a structured form. Interobserver agreement across hospitals ranged from 86% to 95%. Multiple regression models were developed to describe associations between operative time, team membership, miscommunications, interruptions, and total NOTECHS and subscale scores. Results We observed 161 surgical procedures across 8 teams. The total amount of explained variance in NOTECHS and its 5 subscales ranged from 14% (adjusted R2 0.12, p<0.001) to 24% (adjusted R2 0.22, p<0.001). In all models, inverse relationships between the total number of miscommunications and total number of interruptions and teams’ NTS were observed. Conclusions Miscommunications and interruptions impact on team NTS performance. PMID:28137931

  6. Rupture dynamics along bimaterial interfaces: a parametric study of the shear-normal traction coupling

    NASA Astrophysics Data System (ADS)

    Scala, Antonio; Festa, Gaetano; Vilotte, Jean-Pierre

    2017-01-01

    Earthquake ruptures often develop along faults separating materials with dissimilar elastic properties. Due to the broken symmetry, the propagation of the rupture along the bimaterial interface is driven by the coupling between interfacial sliding and normal traction perturbations. We numerically investigate in-plane rupture growth along a planar interface, under slip weakening friction, separating two dissimilar isotropic linearly elastic half-spaces, and we perform a parametric study of the classical Prakash-Clifton regularisation, for different material contrasts. In particular the mesh-dependence and the regularisation-dependence of the numerical solutions are analysed in this parameter space. When the regularisation involves a slip-rate dependent relaxation time, a characteristic sliding distance is identified below which numerical solutions no longer depend on the regularisation parameter, i.e. they are physically well-posed solutions. Such regularisation provides an adaptive high-frequency filter of the slip-induced normal traction perturbations, following the dynamic shrinking of the dissipation zone during the acceleration phase. In contrast, a regularisation involving a constant relaxation time leads to numerical solutions that always depend on the regularisation parameter since it fails in adapting to the shrinking of the process zone. Dynamic regularisation is further investigated using a non-local regularisation based on a relaxation time that depends on the dynamic length of the dissipation zone. Such reformulation is shown to provide similar results as the dynamic time scale regularisation proposed by Prakash-Clifton when the slip rate is replaced by the maximum slip rate along the sliding interface. This leads to the identification of a dissipative length scale associated with the coupling between interfacial sliding and normal traction perturbations, together with a scaling law between the maximum slip rate and the dynamic size of the process zone

  7. Two Case Studies in the Phonetics-Phonology Interface: Evidence from Turkish Voicing and Norwegian Coalescence

    ERIC Educational Resources Information Center

    Feizollahi, Zhaleh

    2010-01-01

    The phonetics-phonology interface has long been debated; some linguists argue for a modular approach (Keating 1984, Pierrehumbert 1990, Zsiga 1997, Cohn 1998), while others argue that there is no interface, and that phonetics and phonology are one and the same (Browman & Goldstein 1989-1992, Ohala 1990). Recent proposals by Gafos (2002), and…

  8. A TEM Study of the Microstructure of Plasma-Sprayed YSZ Near Inter-splat Interfaces

    NASA Astrophysics Data System (ADS)

    Yang, Er-Juan; Luo, Xiao-Tao; Yang, Guan-Jun; Li, Cheng-Xin; Li, Chang-Jiu.

    2015-08-01

    The splat interface bonding state which changes heat transfer conditions and thus the cooling rate during splat cooling may influence the interface microstructure. In this paper, YSZ coating was deposited by atmospheric plasma spraying with substrate cooling during deposition. Subsequent characterization was implemented using high resolution transmission electron microscopy to examine the local microstructures near the interfaces at the bonded and unbonded zones. Selected area diffraction analyses of the splats across both the bonded interface and unbonded interface revealed that all bulk splats present a metastable tetragonal structure. Results showed that the size of columnar grains within a splat was significantly influenced by the interface bonding. At the unbonded region in the splat, large columnar grains form which can be attributed to poor thermal contact of melt to the underlying splat surface before its solidification. At the bonded zones, the splat presents a much fine columnar grain structure, which is attributed to good thermal contact of the melt to the underlying splat before solidification. Moreover, it is evident that the bonded interface region presents a distinct microstructure feature from the fine columnar grains suggesting the crystal defect of high density of dislocations at the interface.

  9. Study program for encapsulation materials interface for low-cost solar array

    NASA Technical Reports Server (NTRS)

    Kaelble, D. H.; Mansfeld, F. B.; Kendig, M.; Leung, C.

    1981-01-01

    The service integrity of the bonded interface in solar cell modules used in solar arrays is addressed. The development of AC impedance as a nondestructive evaluation (NDE) methodology for solar arrays is reported along with development of corrosion models and materials selection criteria for corrosion resistant interfaces.

  10. Study of Metal-NH[subscript 3] Interfaces (Metal= Cu, Ni, Ag) Using Potentiostatic Curves

    ERIC Educational Resources Information Center

    Nunes, Nelson; Martins, Angela; Leitao, Ruben Elvas

    2007-01-01

    Experiment is conducted to determine the kinetic parameters of metal-solution interfaces. During the experiment the kinetic parameters for the interfaces Cu-NH[subscript 3], Ag-NH[subscript 3] and Ni-NH[subscript 3] is easily determined.

  11. Interface Conditions on Postverbal Subjects: A Corpus Study of L2 English

    ERIC Educational Resources Information Center

    Lozano, Cristobal; Mendikoetxea, Amaya

    2010-01-01

    This paper investigates how syntactic knowledge interfaces with other cognitive systems by analysing the production of postverbal subjects, V(erb)-S(ubject) order, in an L1 Spanish-L2 English corpus and a comparable English native corpus. VS order in both native and L2 English is shown to be constrained by properties operating at three interfaces:…

  12. MARKET ASSESSMENT AND TECHNICAL FEASIBILITY STUDY OF PRESSURIZED FLUIDIZED BED COMBUSTION ASH USE

    SciTech Connect

    A.E. Bland; T.H. Brown

    1997-04-01

    Western Research Institute, in conjunction with the Electric Power Research Institute, Foster Wheeler International, Inc. and the US Department of Energy, has undertaken a research and demonstration program designed to examine the market potential and the technical feasibility of ash use options for PFBC ashes. Ashes from the Foster Wheeler Energia Oy pilot-scale circulating PFBC tests in Karhula, Finland, combusting (1) low-sulfur subbituminous and (2) high-sulfur bituminous coal, and ash from the AEP's high-sulfur bituminous coal-fired bubbling PFBC in Brilliant, Ohio, were evaluated in laboratory and pilot-scale ash use testing at WR1. The technical feasibility study examined the use of PFBC ash in construction-related applications, including its use as a cementing material in concrete and use in cement manufacturing, fill and embankment materials, soil stabilization agent, and use in synthetic aggregate production. Testing was also conducted to determine the technical feasibility of PFBC ash as a soil amendment for acidic and sodic problem soils and spoils encountered in agricultural and reclamation applications. The results of the technical feasibility testing indicated the following conclusions. PFBC ash does not meet the chemical requirements as a pozzolan for cement replacement. However, it does appear that potential may exist for its use in cement production as a pozzolan and/or as a set retardant. PFBC ash shows relatively high strength development, low expansion, and low permeability properties that make its use in fills and embankments promising. Testing has also indicated that PFBC ash, when mixed with low amounts of lime, develops high strengths, suitable for soil stabilization applications and synthetic aggregate production. Synthetic aggregate produced from PFBC ash is capable of meeting ASTM/AASHTO specifications for many construction applications. The residual calcium carbonate and calcium sulfate in the PFE3C ash has been shown to be of value in

  13. Study of organic-inorganic hetero-interfaces and electrical transport in semiconducting nanostructures

    NASA Astrophysics Data System (ADS)

    Wagner, Sean Robert

    As the electronics industry continues to evolve and move towards functional electronic devices with increasing complexity and functionality, it becomes important to explore materials outside the regime of conventional semiconductors. Organic semiconducting small molecules have received a large amount of attention due to their high degree of flexibility, the option to perform molecular synthesis to modify their electronic and magnetic properties, and their ability to organize into highly-ordered functionalized nanostructures and thin films. Being able to form complex nanostructures and thin films with molecular precision, while maintaining the ability to tune properties through modifications in the molecular chemistry could result in vast improvements in conventional device architectures. However, before this is realized, there still remains a significant lack of understanding regarding how these molecules interact with various substrate surfaces as well as their intermolecular interactions. The interplay between these interactions can produce drastic changes in the molecular orientation and ordering at the hetero-interface, which can affect the transport properties of the molecular thin film and ultimately modify the performance of the organic electronic device. This study first focuses on the growth dynamics, molecular ordering, and molecular orientation of metal phthalocyanine (MPc) molecules, particularly on Si, a substrate which is notoriously difficult to form an organized organic thin film on due to the surface dangling bonds. By deactivating these bonds, the formation of a highly ordered organic molecular thin film becomes possible. Combining scanning tunneling microscopy, scanning tunneling spectroscopy, low-energy electron diffraction, and density functional theory calculations, the growth evolution of MPc molecules ( M = Zn, Cu, Co) from the single molecule level to multilayered films on the deactivated Si(111)-B surface is investigated. Initial tests are

  14. Space tug/shuttle interface compatibility study. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Shuttle interfaces required for space tug accommodation are primarily involved with supporting and servicing the tug during launch countdown, flight, and postlanding; deploying and retrieving the tug on orbit; and maintaining control over the tug when it is in or near the orbiter. Each of these interface areas was investigated to determine the best physical and operational method of accomplishing the required functions, with an overriding goal of establishing simple and flexible orbiter interface requirements suitable for tug, tug payloads, IUS and other cargo. It is concluded the orbiter payload accommodations and the MSFC baseline tug are generally interface compatible. Specific minor changes to tug and orbiter interfaces were identified to provide full compatibility. A system concept for supporting and deploying tug from orbiter is described.

  15. Development of a teaching tool to encourage high school students to study aerospace technical subjects

    NASA Technical Reports Server (NTRS)

    Gale, Anita; Edwards, Dick

    1998-01-01

    This report details the efforts to develop a design competition aimed at high school students which will encourage them to study aerospace technical subjects. It has been shown that such competitions - based on an industry simulation game - are valuable ways to energize high school students to study in this area. Under the grant, a new competition scenario was developed, in keeping with NASA-Dryden's mission to develop aircraft and foster knowledge about aeronautics. Included are preliminary background materials and information which, if the grant is continued, would form the basis of a national competition for high school students, wherein they would design an Aerospaceport in a future year, taking into consideration the requirements of aircraft, spacecraft- ground transportation systems, passengers who use the facility, and employees who operate it. Many of the Competition methods were studied and tested during two existing local competitions in the disadvantaged communities of Lancaster and Victorville, California.

  16. A Computational Study of Dicationic Ionic Liquids/CO2 Interfaces

    SciTech Connect

    Li, Song; Zhao, Wei; Feng, Guang; Cummings, Peter T.

    2015-02-09

    Our recent studies on CO2 capture using dicationic ionic liquids (DILs) demonstrated that DILs are promising absorbents for CO2 uptake especially compared with monocationic ionic liquids (MILs) analogues, in which each cation carries single positive charge in contrast to two unit charges of a dication. However, DILs/CO2 interfacial properties at the molecular level are still unknown. This work investigated the CO2 absorption properties of representative DILs, 1-alkyl-3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide, [Cn(mim)2](Tf2N)2 (n = 3, 6, 12), using molecular dynamics (MD) simulations. The higher interfacial CO2 density at DIL than that at MIL interfaces suggests the increased CO2 interaction sites in DILs. The interfacial CO2 density also exhibits an alkyl chain length dependence which decreases with the elongation of alkyl chain and proportionally correlates with the content of fluorine atoms at interfaces. Different alkyl chain orientations in DILs were illustrated in contrast to those of MILs; both DILs and CO2 inside DILs exhibit lower diffusivity than MILs, in agreement with the stronger cation–anion binding energy of DILs. Moreover, DILs show a lower H2O and N2 uptake from flue gas compared with MILs, implicating the higher CO2/H2O and CO2/N2 selectivity.

  17. Scanning tunneling microscopy study of molecular order at liquid-solid interfaces

    NASA Astrophysics Data System (ADS)

    Magonov, S. N.; Wawkuschewski, A.; Cantow, H.-J.; Liang, W.; Whangbo, M.-H.

    1994-08-01

    Adsorbates of normal alkane C36H74, cycloalkanes (CH2)48 and (CH2)72, decanol C10H21OH, 4-hexyl-4'-CyanoBiphenyl (6CB) and 4-octyl-4t'-CyanoBiphenyl (8CB) on graphite and β-Nb3I8 were studied by Scanning Tunneling Microscopy (STM), and the molecular arrangements at the liquid-solid interface were examined. Large-scale STM images show that the adsorbates possess complex multilayered structures, and that molecular ordering at the liquid-solid interfaces occurs primarily in the immediate vicinity of the substrate. Molecular-scale STM images are primarily determined by the electronic contributions of the most protruded atoms of the topmost overlayer. The underlying overlayers and the substrate affect the images indirectly by perturbing the topography of the topmost overlayer. The STM images of the adsorbates on graphite show that the atomically flat surface of graphite leads organic molecules to form lamella-like structures, while on the grooved surface of β-Nb3I8, long chain-like molecules are trapped in the grooves. We were unable to image the cycloalkanes on β-Nb3I8, which suggests that the cycloalkanes cannot assemble on the grooved surface due to a mismatch between the molecular shape and surface topography. The layers of 6CB and 8CB adsorbed on β-Nb3I8 exhibit two types of domains, which may be related to how the grooves of the β-Nb3I8 surface are occupied by the organic molecules. The STM images of decanol adsorbed on β-Nb3I8 show two domains of different brightness. The relative brightness of these domains switches reversibly as the gap resistance is changed in the region around -60 MΩ.

  18. Atomistic studies of grain boundaries and heterophase interfaces in alloys and compounds. Final report, July 1987-August 1998

    SciTech Connect

    Vitek, Vaclav

    1998-08-01

    The overarching goal of the research supported by this grant was investigation of the structure and properties of interfaces in multicomponent systems by atomistic modeling. Initially, the research was devoted to studies of segregation to grain boundaries in binary disordered alloys. The next step was then studies of the structure and properties of grain boundaries in ordered compounds, specifically Ni3Al and NiAl, and grain boundary segregation in these compounds in the case of off-stoichiometry. Finally, the structure of Nb/sapphire interfaces, in particular the core configurations of the misfit dislocations, was studied.

  19. Study on feasible technical potential of coal to electricity in china

    NASA Astrophysics Data System (ADS)

    Jia, Dexiang; Tan, Xiandong

    2017-01-01

    The control of bulk coal is one of the important work of air pollution control in China’s future. Existing research mainly focuses on the adaptability, economy, construction and renovation plan, and operation optimization of specific energy substitution utilization, and lacks the strategy research of long-term layout of energy substitution utilization in large area. This paper puts forward a technical potential prediction method of coal to electricity based on the thermal equivalent method, which is based on the characteristics of regional coal consumption, and combined with the trend of adaptability and economy of energy substitution utilization. Also, the paper calculates the comprehensive benefit of coal to electricity according to the varieties of energy consumption and pollutant emission level of unit energy consumption in China’s future. The research result shows that the development technical potential of coal to electricity in China is huge, about 1.8 trillion kWh, including distributed electric heating, heat pump and electric heating boiler, mainly located in North China, East China, and Northeast China. The implementation of coal to electricity has remarkable comprehensive benefits in energy conservation and emission reduction, and improvement of energy consumption safety level. Case study shows the rationality of the proposed method.

  20. Technical Quality of Root Fillings Performed by Undergraduate Students: A Radiographic Study

    PubMed Central

    Blažić, Larisa; Kantardžić, Ivana

    2014-01-01

    Aim. The aim of this study was to evaluate the radiographic technical quality of endodontic treatment performed by undergraduate students at the School of Dentistry, Faculty of Medicine, University of Novi Sad, Serbia. Materials and Methods. Electronic records of 220 patients treated by final-year undergraduate students during the school year 2011/2012 were examined, and the final sample consisted of 212 patients, 322 teeth, and 565 root canals. The criteria for overall radiographic adequacy of root canal fillings were defined as the presence of adequate length and density and absence of iatrogenic errors (ledge, fractured instrument, untreated canal, and apical transportation). Chi-square test was used to determine statistical significance between different parameters. Results. Adequate root canal fillings were found in 74.22% of the teeth. The percentage of root fillings with adequate length and density was 89.73% and 92.6%, respectively. Fractured instruments and ledges were present in 16 root canals (2.8%), while the presence of missed canal and apical transportation was observed in 2 cases, each (0.3%). Conclusions. Overall, the technical quality of root canal fillings performed by undergraduate students was satisfactory. PMID:24672365

  1. A Model Study of Inclusions Deposition, Macroscopic Transport, and Dynamic Removal at Steel-Slag Interface for Different Tundish Designs

    NASA Astrophysics Data System (ADS)

    Chen, Chao; Ni, Peiyuan; Jonsson, Lage Tord Ingemar; Tilliander, Anders; Cheng, Guoguang; Jönsson, Pär Göran

    2016-06-01

    This paper presents computational fluid dynamics (CFD) simulation results of inclusions macroscopic transport as well as dynamic removal in tundishes. A novel treatment was implemented using the deposition velocity calculated by a revised unified Eulerian deposition model to replace the widely used Stokes rising velocity in the boundary conditions for inclusions removal at the steel-slag interface in tundishes. In this study, the dynamic removal for different size groups of inclusions at different steel-slag interfaces (smooth or rough) with different absorption conditions at the interface (partially or fully absorbed) in two tundish designs was studied. The results showed that the dynamic removal ratios were higher for larger inclusions than for smaller inclusions. Besides, the dynamic removal ratio was higher for rough interfaces than for smooth interfaces. On the other hand, regarding the cases when inclusions are partially or fully absorbed at a smooth steel-slag interface, the removal ratio values are proportional to the absorption proportion of inclusions at the steel-slag interface. Furthermore, the removal of inclusions in two tundish designs, i.e., with and without a weir and a dam were compared. Specifically, the tundish with a weir and a dam exhibited a better performance with respect to the removal of bigger inclusions (radii of 5, 7, and 9 μm) than that of the case without weir and dam. That was found to be due to the strong paralleling flow near the middle part of the top surface. However, the tundish without weir and dam showed a higher removal ratio of smaller inclusions (radius of 1 μm). The reason could be the presence of a paralleling flow near the inlet zone, where the inclusions deposition velocities were much higher than in other parts.

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

    ERIC Educational Resources Information Center

    Mishra, Arun K.

    Education has a place of high priority on India's development agenda. The technical/vocational education (TVE) system is multisectoral with each ministry responsible for labor force development in that sector. The TVE programs in the formal education system are either state delivered or financed. The higher secondary vocational education program…

  3. Case Study on Technical and Vocational Education in Japan. Case Studies on Technical and Vocational Education in Asia and the Pacific.

    ERIC Educational Resources Information Center

    Iwamoto, Muneharu

    In the course of Japan's economic progress, remarkable changes have occurred in the structure of industry and employment. Workers are in extremely short supply in such occupations as mining, manufacturing and construction, services, transportation and communication, sales, and professional and technical. On the basis of recommendations of the…

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

    ERIC Educational Resources Information Center

    Hee, Tieng Fok

    The economic profile of Malaysia has changed from an economy mainly based on agriculture and the production of tin ore to a more balanced economy with continuing growth in the manufacturing and industrial sectors. Educational programs need to be upgraded and improved, particularly the direction and development of technical and vocational education…

  5. A socio-technical systems approach to studying interruptions: understanding the interrupter's perspective.

    PubMed

    Rivera, A Joy

    2014-05-01

    The purpose of this study was to understand the cognitive processes underlying nurses' decision to interrupt other nurses. The Institute of Medicine (2000) reported that interruptions are likely contributors to medical errors. Unfortunately, the research to date has been quite homogenous, focusing only on the healthcare provider being interrupted, ignoring the true complexities of interruptions. This study took a socio-technical approach being the first to examine interruptions from the viewpoint of the interrupting nurse. Over 15 h of observations and 10 open-ended interviews with expert nurses in a Neuroscience Surgical Intensive Care Unit were conducted. It was found that nurses conduct a quick cost-benefit assessment to determine the interruptibility of other nurses and whether an interruption is value-added vs. non-value added. To complete the assessment, nurses consider several conditional factors related to the interruptee, the interrupter, and the nature of the interruption content, and different potential consequences of the interruption.

  6. Video-microscopic observation of ionic liquid/alcohol interface and the corresponding molecular simulation study

    NASA Astrophysics Data System (ADS)

    Zhu, Peixi

    This research is aimed at studying the ionic liquid/n-pentanol interface via video-microscopy and molecular dynamic simulations. Understanding the interfacial phenomena and interfacial transport between ionic liquids and other liquids is of interest to the development and application of ionic liquids in a number of areas. One such area is the biphasic hydroformylation of alkenes to obtain alcohol and aldehyde, in which case ionic liquid is the reaction medium where a catalyst resides. The dissolution of an ionic liquid into an alcohol was studied by microscopically observing and measuring the shrinking of a micropipette-produced droplet in real time. Although microscopic investigation of droplet dissolution has been studied before, no attempt had been made to measure the diffusion coefficient D of the droplet species in the surrounding medium. A key finding of this work is that the Epstein-Plesset mathematical model, which describes the dissolution of a droplet/bubble in another fluid medium, can be used to measure D. Other experimental studies of the ionic liquid/alcohol system include electrical conductivity and UV-visible spectroscopy measurements of solutions of 1-hexyl-3-methylimidazolium tetrafluoroborate in n-pentanol. Those experiments were done in order to understand the molecular state of the particular ionic liquid in n-pentanol, as well as obtaining the dissociation constant K of such weak electrolyte solution. The experimental results provide an entry to the assessment of ionic liquid interaction with n-pentanol at molecular scale. Subsequently, molecular dynamics simulation was implemented for the investigation of such interaction. The computation started with simulation of the bulk phase of 1-butyl-3-methylimidazolium tetrafluoroborate, an affine ionic liquid on which molecular simulations had already been reported. A generalized probability based on Fuoss approximation for the closest ion to a distinguished countercharge ion was developed. In

  7. Interface resistance

    NASA Astrophysics Data System (ADS)

    Sinkkonen, Juha

    1983-11-01

    Interface resistance is studied by using the Landauer formula which relates the resistance to the quantum mechanical transmission coefficient. A simple rederivation of the Landauer formula is given. Using a step-like potential barrier as a model for the metal-semiconductor contact an analytical expression for the effective Richardson constant is derived. As an other application the grain boundary resistance in polycrystalline semiconductors is studied. The short-range potential fluctuation associated with the grain boundary is described by a rectangular potential barrier. The results for the grain boundary limited mobility cover both the strong and weak scattering regimes.

  8. Analysis of E-Mail Produced by Middle School Students with Disabilities Using Accessible Interfaces: An Exploratory Study

    ERIC Educational Resources Information Center

    Sohlberg, McKay Moore; Todis, Bonnie; Fickas, Stephen; Ehlhardt, Laurie

    2011-01-01

    The goal of this exploratory study was to investigate electronic communication as a potential method to enhance social communication in a range of students with disabilities. This study investigated the usability of an adapted e-mail interface, TeenMail, for 11 middle school students with significant learning and communication impairments who…

  9. A multievent study of the coincidence of heliospheric current sheet and stream interface

    NASA Astrophysics Data System (ADS)

    Huang, Jia; Liu, Yong C.-M.; Qi, Zhaohui; Klecker, Berndt; Marghitu, Octav; Galvin, Antoinette B.; Farrugia, Charles J.; Li, Xiaoyu

    2016-11-01

    Generally, the heliospheric current sheet (HCS) is separated from the stream interface (SI) at about 1 AU. A recent study found an event where the HCS coincides with the SI, and in which the HCS is separated from the true sector boundary (TSB), defined by the switch of suprathermal electron pitch angle distributions. We present a multievent study by using STEREO, ACE, and Wind data during 2007 to 2010 to investigate whether other classes of such coincidence cases exist, as well as their stability. We find coincidence cases related to ideal HCSs, separated TSB and HCS, or heat flux dropouts in the vicinity; therefore, we define them as types I, II, and III. Among the nine coincidence cases, there are seven type I, one type II, and one type III. For each type, a possible schematic origin is presented. We also compared the observations on different spacecraft. Only two out of nine cases are observed by several spacecraft with a large separation, indicating that the coincidence structures are usually unstable. The study also shows that the coincidence cases have a variable connection with pseudostreamers. Interchange reconnection and pseudostreamers could play a role in forming these coincidence cases and lead to different configurations in different situations.

  10. Evaluation of a new approach for modelling the screw-bone interface in a locking plate fixation: a corroboration study.

    PubMed

    Moazen, Mehran; Mak, Jonathan H; Jones, Alison C; Jin, Zhongmin; Wilcox, Ruth K; Tsiridis, Eleftherios

    2013-07-01

    Computational modelling of the screw-bone interface in fracture fixation constructs is challenging. While incorporating screw threads would be a more realistic representation of the physics, this approach can be computationally expensive. Several studies have instead suppressed the threads and modelled the screw shaft with fixed conditions assumed at the screw-bone interface. This study assessed the sensitivity of the computational results to modelling approaches at the screw-bone interface. A new approach for modelling this interface was proposed, and it was tested on two locking screw designs in a diaphyseal bridge plating configuration. Computational models of locked plating and far cortical locking constructs were generated and compared to in vitro models described in prior literature to corroborate the outcomes. The new approach led to closer agreement between the computational and the experimental stiffness data, while the fixed approach led to overestimation of the stiffness predictions. Using the new approach, the pattern of load distribution and the magnitude of the axial forces, experienced by each screw, were compared between the locked plating and far cortical locking constructs. The computational models suggested that under more severe loading conditions, far cortical locking screws might be under higher risk of screw pull-out than the locking screws. The proposed approach for modelling the screw-bone interface can be applied to any fixation involved application of screws.

  11. Technical program to study the benefits of nonlinear analysis methods in LWR component designs. Technical report TR-3723-1

    SciTech Connect

    Raju, P. P.

    1980-05-01

    This report summarizes the results of the study program to assess the benefits of nonlinear analysis methods in Light Water Reactor (LWR) component designs. The current study reveals that despite its increased cost and other complexities, nonlinear analysis is a practical and valuable tool for the design of LWR components, especially under ASME Level D service conditions (faulted conditions) and it will greatly assist in the evaluation of ductile fracture potential of pressure boundary components. Since the nonlinear behavior is generally a local phenomenon, the design of complex components can be accomplished through substructuring isolated localized regions and evaluating them in detail using nonlinear analysis methods.

  12. Transforming Further Education and Training in South Africa: A Case Study of Technical Colleges in KwaZulu-Natal. Volume One: Qualitative Findings and Analysis.

    ERIC Educational Resources Information Center

    Kraak, Andre; Hall, Graham

    This book contains eight papers from a detailed study of technical college provision in KwaZulu-Natal, South Africa, that raised the following four issues relevant to the transformation of technical colleges across South Africa: (1) the teaching and learning environment at technical colleges is suboptimal; (2) social relations at the technical…

  13. The Evaluation of the Effectiveness of ESP Courses in Enhancing Technical Translation Proficiency: A Case Study of ESP Course for Mechanical Engineering Students

    ERIC Educational Resources Information Center

    Hatam, Amir Hussein; Shafiei, Shilan

    2012-01-01

    The purpose of the present study was twofold. Firstly, it tried to investigate the relationship between the technical English proficiency of the students of Mechanical Engineering in the universities of Iran and their technical translation proficiency in translating technical texts of Mechanics. Secondly, it attempted to evaluate the effectiveness…

  14. Tunneling Spectroscopy Studies of Epitaxial Graphene on Silicon Carbide(0001) and Its Interfaces

    NASA Astrophysics Data System (ADS)

    Sandin, Andreas Axel Tomas

    A two dimensional network of sp2 bonded carbon atoms is defined as graphene. This novel material possesses remarkable electronic properties due to its unique band structure at the vicinity of the Fermi energy. The toughest challenge to bring use of graphene electronic properties in device geometries is that graphene is exceptionally sensitive to its electrical environment for integration into macroscopic system of electrical contacts and substrates. One of the most promising substrates for graphene is the polar surfaces of SiC for the reason it can be grown epitaxially by sublimating Si from the top-most SiC atomic layers. In this work, the interfaces of graphene grown on the Si-terminated polar surface SiC(0001) is studied in UHV using scanning tunneling microscopy (STM), scanning tunneling spectroscopy (STS), low energy electron diffraction (LEED) and auger electron Spectroscopy (AES). STM is used image the graphene surface and interfaces with the capability of atomic resolution. LEED is used to study surface atomic reciprocal ordering and AES is used to determine surface atomic composition during the graphene formation. Interfacial layer (Buffer layer), Single layer graphene and bilayer graphene are identified electronically by means of probing the first member of the image potential derived state. This state is found by dZ/dV spectroscopy in the high energy unoccupied states and is exceptionally sensitive to electrostatic changes to the surface which is detected by energy shifts of image potential states (IPS). This sensitivity is utilized to probe the graphene screening of external electric fields by varying the electric field in the tunneling junction and addresses the fact that charged impurity scattering is likely to be crucial for epitaxial graphene on SiC(0001) when it comes to transport parameters. Shifts of IPS energy position has also been used verify work function changes for identification of several Sodium Intercalation structures of epitaxial

  15. 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 sections in this report include: Single Stage to Orbit (SSTO) Design Ground-rules; Operations Issues and Lessons Learned; Vertical-Takeoff/Landing Versus Vertical-Takeoff/Horizontal-Landing; SSTO Design Results; SSTO Simulation Results; SSTO Assessment Results; SSTO Sizing Tool User's Guide; SSto Turnaround Assessment Report; Ground Operations Assessment First Year Executive Summary; Health Management System Definition Study; Major TA-2 Presentations; First Lunar Outpost Heavy Lift Launch Vehicle Design and Assessment; and the section, Russian Propulsion Technology Assessment Reports.

  16. In situ study of the initiation of hydrogen bubbles at the aluminium metal/oxide interface.

    PubMed

    Xie, De-Gang; Wang, Zhang-Jie; Sun, Jun; Li, Ju; Ma, Evan; Shan, Zhi-Wei

    2015-09-01

    The presence of excess hydrogen at the interface between a metal substrate and a protective oxide can cause blistering and spallation of the scale. However, it remains unclear how nanoscale bubbles manage to reach the critical size in the first place. Here, we perform in situ environmental transmission electron microscopy experiments of the aluminium metal/oxide interface under hydrogen exposure. It is found that once the interface is weakened by hydrogen segregation, surface diffusion of Al atoms initiates the formation of faceted cavities on the metal side, driven by Wulff reconstruction. The morphology and growth rate of these cavities are highly sensitive to the crystallographic orientation of the aluminium substrate. Once the cavities grow to a critical size, the internal gas pressure can become great enough to blister the oxide layer. Our findings have implications for understanding hydrogen damage of interfaces.

  17. Mission control communications interface requirements study, space transportation system, volume 1

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Communications traffic models required by the STS Operator to satisfy the operational requirements and concepts were developed. Detailed requirements for the ground system required for flight control of the STS and interface with Payload Operations Control Centers were constructed.

  18. Satellite studies of suspended matter and aquatic interfaces in Delaware Bay

    NASA Technical Reports Server (NTRS)

    Klemas, V. (Principal Investigator); Srna, R.; Treasure, W.

    1973-01-01

    The author has identified the following significant results. Three successful ERTS-1 satellite passes have produced synoptic imagery showing distribution of suspended matter and aquatic interfaces over Delaware Bay and adjacent Atlantic coastal regions. The interfaces are a major hydrographic feature in Delaware Bay and frequently include regions of high convergence. In the upper and middle bay the interfaces tend to align along the flow axis of the river and parallel to the shoreline. A correlation has been found between the concentration of sand particles in suspension and the depth, suggesting that most of the heavier particles are lifted into temporary suspension over shoals and shallow areas by currents and waves. The second type of interface is primarily a tidal intrusion of shelf water into the bay during incipient flood tide, with associated discontinuities in salinity and temperature. The convergence properties of such fronts attract heavy accumulations of foam which were found to contain strong concentrations of heavy metals and other toxic substances.

  19. An X-ray magnetic circular dichroism study of the interface Magnetism in titanate Heterostructures

    NASA Astrophysics Data System (ADS)

    Salluzzo, Marco; CNR-SPIN Team

    2014-03-01

    The 2D-electron system (2DES) created at the interface between LaAlO3 and SrTiO3 have attracted strong interest in recent years. This system shows an intriguing inversion the Ti3d bands hierarchy at the interface respect the bulk, and some reports even suggested coexistence between ferromagnetism and superconductivity. By using x-ray magnetic circular dichroism we show that oxygen vacancies induce magnetic interfacial localized Ti3 + states, which couple to the 2DES, with a negative exchange interaction. The magnetic dichroism signal is quenched in standard LAO/STO interfaces annealed in high oxygen pressure after the deposition and showing a homogeneous superconducting ground state, suggesting a decisive role of oxygen vacancies in the magnetism of these oxide interfaces.

  20. In situ study of the initiation of hydrogen bubbles at the aluminium metal/oxide interface

    NASA Astrophysics Data System (ADS)

    Xie, De-Gang; Wang, Zhang-Jie; Sun, Jun; Li, Ju; Ma, Evan; Shan, Zhi-Wei

    2015-09-01

    The presence of excess hydrogen at the interface between a metal substrate and a protective oxide can cause blistering and spallation of the scale. However, it remains unclear how nanoscale bubbles manage to reach the critical size in the first place. Here, we perform in situ environmental transmission electron microscopy experiments of the aluminium metal/oxide interface under hydrogen exposure. It is found that once the interface is weakened by hydrogen segregation, surface diffusion of Al atoms initiates the formation of faceted cavities on the metal side, driven by Wulff reconstruction. The morphology and growth rate of these cavities are highly sensitive to the crystallographic orientation of the aluminium substrate. Once the cavities grow to a critical size, the internal gas pressure can become great enough to blister the oxide layer. Our findings have implications for understanding hydrogen damage of interfaces.

  1. The power of a collaborative relationship between technical assistance providers and community prevention teams: A correlational and longitudinal study

    PubMed Central

    Chilenski, Sarah M.; Perkins, Daniel F.; Olson, Jonathan; Hoffman, Lesa; Feinberg, Mark E.; Greenberg, Mark; Welsh, Janet; Crowley, D. Max; Spoth, Richard

    2015-01-01

    Background Historically, effectiveness of community collaborative prevention efforts has been mixed. Consequently, research has been undertaken to better understand the factors that support their effectiveness; theory and some related empirical research suggests that the provision of technical assistance is one important supporting factor. The current study examines one aspect of technical assistance that may be important in supporting coalition effectiveness, the collaborative relationship between the technical assistance provider and site lead implementer. Methods Four and one-half years of data were collected from technical assistance providers and prevention team members from the 14 community prevention teams involved in the PROSPER project. Results Spearman correlation analyses with longitudinal data show that the levels of the collaborative relationship during one phase of collaborative team functioning associated with characteristics of internal team functioning in future phases. Conclusions Results suggest that community collaborative prevention work should consider the collaborative nature of the technical assistance provider – prevention community team relationship when designing and conducting technical assistance activities, and it may be important to continually assess these dynamics to support high quality implementation. PMID:26476860

  2. Wildland-Urban Interface Fires and Socioeconomic Conditions: A Case Study of a Northwestern Patagonia City

    NASA Astrophysics Data System (ADS)

    de Torres Curth, Monica; Biscayart, Carolina; Ghermandi, Luciana; Pfister, Gabriela

    2012-04-01

    In many regions of the world, fires are primarily of anthropogenic origin. In northwestern Patagonia, the number of fires is not correlated with meteorological variables, but is concentrated in urban areas. This study was conducted in the wildland-urban interface (WUI) area of San Carlos de Bariloche (Patagonia, Argentina), within the Nahuel Huapi National Park. WUI fires are particularly problematic because, besides people and goods, they represent a danger to protected areas. We studied the relationship between fire records and socioeconomic indicators within the WUI of San Carlos de Bariloche. We conducted a Multiple Correspondence Factorial Analysis and an Ascendant Hierarchical Classification of the city neighborhoods. The results show that the neighborhoods in Bariloche can be divided into three classes: High Socioeconomic Fire Risk neighborhoods, including neighborhoods with the highest fire rates, where people have low instruction level, high levels of unsatisfied basic needs and high unemployment levels; Low Socioeconomic Fire Risk neighborhoods, that groups neighborhoods which present the opposite characterization, and Moderate Socioeconomic Fire Risk neighborhoods, which are more heterogeneous. Once neighborhoods were classified, a Socioeconomic Fire Risk map was generated, supplementing the existing WUI Fire Danger map. Our results emphasize the relevance of socioeconomic variables to fire policies.

  3. Wildland-urban interface fires and socioeconomic conditions: a case study of a northwestern Patagonia city.

    PubMed

    de Torres Curth, Monica; Biscayart, Carolina; Ghermandi, Luciana; Pfister, Gabriela

    2012-04-01

    In many regions of the world, fires are primarily of anthropogenic origin. In northwestern Patagonia, the number of fires is not correlated with meteorological variables, but is concentrated in urban areas. This study was conducted in the wildland-urban interface (WUI) area of San Carlos de Bariloche (Patagonia, Argentina), within the Nahuel Huapi National Park. WUI fires are particularly problematic because, besides people and goods, they represent a danger to protected areas. We studied the relationship between fire records and socioeconomic indicators within the WUI of San Carlos de Bariloche. We conducted a Multiple Correspondence Factorial Analysis and an Ascendant Hierarchical Classification of the city neighborhoods. The results show that the neighborhoods in Bariloche can be divided into three classes: High Socioeconomic Fire Risk neighborhoods, including neighborhoods with the highest fire rates, where people have low instruction level, high levels of unsatisfied basic needs and high unemployment levels; Low Socioeconomic Fire Risk neighborhoods, that groups neighborhoods which present the opposite characterization, and Moderate Socioeconomic Fire Risk neighborhoods, which are more heterogeneous. Once neighborhoods were classified, a Socioeconomic Fire Risk map was generated, supplementing the existing WUI Fire Danger map. Our results emphasize the relevance of socioeconomic variables to fire policies.

  4. Dynamic modeling efforts for system interface studies for nuclear hydrogen production.

    SciTech Connect

    Vilim, R. B.; Nuclear Engineering Division

    2007-08-15

    System interface studies require not only identifying economically optimal equipment configurations, which involves studying mainly full power steady-state operation, but also assessing the operability of a design during load change and startup and assessing safety-related behavior during upset conditions. This latter task is performed with a dynamic simulation code. This report reviews the requirements of such a code. It considers the types of transients that will need to be simulated, the phenomena that will be present, the models best suited for representing the phenomena, and the type of numerical solution scheme for solving the models to obtain the dynamic response of the combined nuclear-hydrogen plant. Useful insight into plant transient behavior prior to running a dynamics code is obtained by some simple methods that take into account component time constants and energy capacitances. Methods for determining reactor stability, plant startup time, and temperature response during load change, and tripping of the reactor are described. Some preliminary results are presented.

  5. Evaluation of Different EEG Acquisition Systems Concerning Their Suitability for Building a Brain-Computer Interface: Case Studies.

    PubMed

    Pinegger, Andreas; Wriessnegger, Selina C; Faller, Josef; Müller-Putz, Gernot R

    2016-01-01

    One important aspect in non-invasive brain-computer interface (BCI) research is to acquire the electroencephalogram (EEG) in a proper way. From an end-user perspective, it means with maximum comfort and without any extra inconveniences (e.g., washing the hair), whereas from a technical perspective, the signal quality has to be optimal to make the BCI work effectively and efficiently. In this work, we evaluated three different commercially available EEG acquisition systems that differ in the type of electrodes (gel-, water-, and dry-based), the amplifier technique, and the data transmission method. Every system was tested regarding three different aspects, namely, technical, BCI effectiveness and efficiency (P300 communication and control), and user satisfaction (comfort). We found that water-based system had the lowest short circuit noise level, the hydrogel-based system had the highest P300 spelling accuracies, and the dry electrode-based system caused the least inconveniences. Therefore, building a reliable BCI is possible with all the evaluated systems, and it is on the user to decide which system meets the given requirements best.

  6. Evaluation of Different EEG Acquisition Systems Concerning Their Suitability for Building a Brain–Computer Interface: Case Studies

    PubMed Central

    Pinegger, Andreas; Wriessnegger, Selina C.; Faller, Josef; Müller-Putz, Gernot R.

    2016-01-01

    One important aspect in non-invasive brain–computer interface (BCI) research is to acquire the electroencephalogram (EEG) in a proper way. From an end-user perspective, it means with maximum comfort and without any extra inconveniences (e.g., washing the hair), whereas from a technical perspective, the signal quality has to be optimal to make the BCI work effectively and efficiently. In this work, we evaluated three different commercially available EEG acquisition systems that differ in the type of electrodes (gel-, water-, and dry-based), the amplifier technique, and the data transmission method. Every system was tested regarding three different aspects, namely, technical, BCI effectiveness and efficiency (P300 communication and control), and user satisfaction (comfort). We found that water-based system had the lowest short circuit noise level, the hydrogel-based system had the highest P300 spelling accuracies, and the dry electrode-based system caused the least inconveniences. Therefore, building a reliable BCI is possible with all the evaluated systems, and it is on the user to decide which system meets the given requirements best. PMID:27746714

  7. Instrument constraints and interface specifications. Earth Observatory Satellite system definition study (EOS)

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The equipment specifications for the thematic mapper and high resolution pointable imager for use on the Earth Observatory Satellite (EOS) are presented. The interface requirements of the systems are defined. The interface requirements are extracted from the equipment specifications and are intended as a summary to be used by the system and spacecraft designer. The appropriate documentation from which the specifications of the equipment are established are identified.

  8. X-ray scattering studies of the Si-SiO2 interface

    NASA Astrophysics Data System (ADS)

    Fuoss, P. H.; Norton, L. J.; Brennan, S.; Fischer-Colbrie, A.

    1988-02-01

    We report observation of microcrystalline interface phases at the SiO2-Si(001) interface. The crystallites have varying degrees of orientational order with respect to the substrate depending on preparation techniques. Most of the diffraction peaks from these phases can be indexed as due to the α-cristobalite structure. Data are presented for oxides prepared on Si(001) surfaces by thermal oxidation, by electron beam evaporation, and by native oxide formation.

  9. Human-machine interface (HMI) report for 241-SY-101 data acquisition [and control] system (DACS) upgrade study

    SciTech Connect

    Truitt, R.W.

    1997-10-22

    This report provides an independent evaluation of information for a Windows based Human Machine Interface (HMI) to replace the existing DOS based Iconics HMI currently used in the Data Acquisition and Control System (DACS) used at Tank 241-SY-101. A fundamental reason for this evaluation is because of the difficulty of maintaining the system with obsolete, unsupported software. The DACS uses a software operator interface (Genesis for DOS HMI) that is no longer supported by its manufacturer, Iconics. In addition to its obsolescence, it is complex and difficult to train additional personnel on. The FY 1997 budget allocated $40K for phase 1 of a software/hardware upgrade that would have allowed the old DOS based system to be replaced by a current Windows based system. Unfortunately, budget constraints during FY 1997 has prompted deferral of the upgrade. The upgrade needs to be performed at the earliest possible time, before other failures render the system useless. Once completed, the upgrade could alleviate other concerns: spare pump software may be able to be incorporated into the same software as the existing pump, thereby eliminating the parallel path dilemma; and the newer, less complex software should expedite training of future personnel, and in the process, require that less technical time be required to maintain the system.

  10. Physicochemical Study of Viral Nanoparticles at the Air/Water Interface.

    PubMed

    Torres-Salgado, Jose F; Comas-Garcia, Mauricio; Villagrana-Escareño, Maria V; Durán-Meza, Ana L; Ruiz-García, Jaime; Cadena-Nava, Ruben D

    2016-07-07

    The assembly of most single-stranded RNA (ssRNA) viruses into icosahedral nucleocapsids is a spontaneous process driven by protein-protein and RNA-protein interactions. The precise nature of these interactions results in the assembly of extremely monodisperse and structurally indistinguishable nucleocapsids. In this work, by using a ssRNA plant virus (cowpea chlorotic mottle virus [CCMV]) as a charged nanoparticle we show that the diffusion of these nanoparticles from the bulk solution to the air/water interface is an irreversible adsorption process. By using the Langmuir technique, we measured the diffusion and adsorption of viral nucleocapsids at the air/water interface at different pH conditions. The pH changes, and therefore in the net surface charge of the virions, have a great influence in the diffusion rate from the bulk solution to the air/water interface. Moreover, assembly of mesoscopic and microscopic viral aggregates at this interface depends on the net surface charge of the virions and the surface pressure. By using Brewster's angle microscopy we characterized these structures at the interface. Most common structures observed were clusters of virions and soap-frothlike micron-size structures. Furthermore, the CCMV films were compressed to form monolayers and multilayers from moderate to high surface pressures, respectively. After transferring the films from the air/water interface onto mica by using the Langmuir-Blodgett technique, their morphology was characterized by atomic force microscopy. These viral monolayers showed closed-packing nano- and microscopic arrangements.

  11. Atomistic study of the structural and electronic properties of a-Si:H/c-Si interfaces.

    PubMed

    Santos, Iván; Cazzaniga, Marco; Onida, Giovanni; Colombo, Luciano

    2014-03-05

    We investigate the structural and electronic properties of the interface between hydrogenated amorphous silicon (a-Si:H) and crystalline silicon (c-Si) by combining tight-binding molecular dynamics and DFT ab initio electronic structure calculations. We focus on the c-Si(100)(1×1)/a-Si:H, c-Si(100)(2×1)/a-Si:H and c-Si(111)/a-Si:H interfaces, due to their technological relevance. The analysis of atomic rearrangements induced at the interface by the interaction between H and Si allowed us to identify the relevant steps that lead to the transformation from c-Si(100)(1×1)/a-Si:H to c-Si(100)(2×1)/a-Si:H. The interface electronic structure is found to be characterized by spatially localized mid-gap states. Through them we have identified the relevant atomic structures responsible for the interface defect states, namely: dangling-bonds, H bridges, and strained bonds. Our analysis contributes to a better understanding of the role of such defects in c-Si/a-Si:H interfaces.

  12. Adsorption and solvation of ethanol at the water liquid-vapor interface: a molecular dynamics study

    NASA Technical Reports Server (NTRS)

    Wilson, M. A.; Pohorille, A.

    1997-01-01

    The free energy profiles of methanol and ethanol at the water liquid-vapor interface at 310K were calculated using molecular dynamics computer simulations. Both alcohols exhibit a pronounced free energy minimum at the interface and, therefore, have positive adsorption at this interface. The surface excess was computed from the Gibbs adsorption isotherm and was found to be in good agreement with experimental results. Neither compound exhibits a free energy barrier between the bulk and the surface adsorbed state. Scattering calculations of ethanol molecules from a gas phase thermal distribution indicate that the mass accommodation coefficient is 0.98, and the molecules become thermalized within 10 ps of striking the interface. It was determined that the formation of the solvation structure around the ethanol molecule at the interface is not the rate-determining step in its uptake into water droplets. The motion of an ethanol molecule in a water lamella was followed for 30 ns. The time evolution of the probability distribution of finding an ethanol molecule that was initially located at the interface is very well described by the diffusion equation on the free energy surface.

  13. Numerical studies of the effects of jet-induced mixing on liquid-vapor interface condensation

    NASA Technical Reports Server (NTRS)

    Lin, Chin-Shun

    1989-01-01

    Numerical solutions of jet-induced mixing in a partially full cryogenic tank are presented. An axisymmetric laminar jet is discharged from the central part of the tank bottom toward the liquid-vapor interface. Liquid is withdrawn at the same volume flow rate from the outer part of the tank. The jet is at a temperature lower than the interface, which is maintained at a certain saturation temperature. The interface is assumed to be flat and shear-free and the condensation-induced velocity is assumed to be negligibly small compared with radial interface velocity. Finite-difference method is used to solve the nondimensional form of steady state continuity, momentum, and energy equations. Calculations are conducted for jet Reynolds numbers ranging from 150 to 600 and Prandtl numbers ranging from 0.85 to 2.65. The effects of above stated parameters on the condensation Nusselt and Stanton numbers which characterize the steady-state interface condensation process are investigated. Detailed analysis to gain a better understanding of the fundamentals of fluid mixing and interface condensation is performed.

  14. Simulation study on factors influencing the entrainment behavior of liquid steel as bubbles pass through the steel/slag interface

    NASA Astrophysics Data System (ADS)

    Li, Xiang; Bao, Yan-ping; Wang, Min; Lin, Lu

    2016-05-01

    In this study, a water/silicone oil interface was used to simulate the steel/slag interface in a converter. A high-speed camera was used to record the entrainment process of droplets when air bubbles were passed through the water/silicone oil interface. Motion parameters of the bubbles and droplets were obtained using particle kinematic analysis software, and the entrainment rate of the droplets was calculated. It was found that the entrainment rate decreased from 29.5% to 0 when the viscosity of the silicone oil was increased from 60 mPa·s to 820 mPa·s in the case of bubbles with a 5 mm equivalent diameter passing through the water/silicone oil interface. The results indicate that increasing the viscosity of the silicone oil is conducive to reducing the entrainment rate. The entrainment rate increased from 0 to 136.3% in the case of silicone oil with a viscosity of 60 mPa·s when the equivalent diameter of the bubbles was increased from 3 mm to 7 mm. We therefore conclude that small bubbles are also conductive to reducing the entrainment rate. The force analysis results for the water column indicate that the entrainment rate of droplets is affected by the velocity of the bubble passing through the water/silicone oil interface and that the entrainment rate decreases with the bubble velocity.

  15. A molecular-dynamics study of a model SN1 dissociation reaction at the water liquid/vapor interface

    NASA Astrophysics Data System (ADS)

    Winter, Nicole; Benjamin, Ilan

    2005-05-01

    The thermodynamics and dynamics of a model SN1 reaction: t-BuCl →t-Bu++Cl- is studied at the water liquid/vapor interface using molecular-dynamics computer simulations. The empirical valence bond approach is used to couple two diabatic states, covalent and ionic, in the electronically adiabatic limit. Umbrella sampling calculations are used to calculate the potential of mean force along the reaction coordinate (defined as the t-Bu to Cl distance) in bulk water and in several locations at the interface. We find a significant increase of the dissociation barrier height and of the reaction free energy at the interface relative to the bulk. This is shown to be due to the reduced polarity of the interface. Reactive flux correlation function calculations show significant deviation of the rate constant from the transition-state theory: The transmission coefficients range from 0.49 in the bulk to 0.05 above the Gibbs surface. The low transmission coefficient at the interface despite the lower friction is shown to be due to slow vibrational relaxation.

  16. A first principles thermodynamic study of Si-HfO2 and Pt-HfO2 interfaces

    NASA Astrophysics Data System (ADS)

    Zhu, Hong; Ramprasad, Rampi

    2012-02-01

    Atomic-level control of dielectric-semiconductor and dielectric-metal interfaces has become critical in determining the properties of the emerging high-k oxide-based MOSFETs. Using Si-HfO2 and Pt-HfO2 as an example, we investigate the evolution of these interface structures and electronic properties as a function of processing conditions by combining density functional theory results and statistical thermodynamics. Firstly, using first principles thermodynamics (FPTs), we determine the phase diagrams of Si-HfO2 and Pt-HfO2 interfaces. The vibrational and configurational entropic contributions to the free energies of the condensed phases are explicitly included. We demonstrate that the predictions of the FPT approach are in quantitative agreement with experiments for the interfaces considered. Secondly, a parameter-free methodology to determine the work function shift (or effective work function, EWF) of metal when interfaced with oxide is developed. This strategy is combined with statistical thermodynamics to predict the most probable EWF at given processing condition. The favorable agreement between the computed and experimental EWFs under generally adopted conditions is indicative of the usefulness of such full first-principles property-processing relationship studies.

  17. Studying bacterial hydrophobicity and biofilm formation at liquid-liquid interfaces through interfacial rheology and pendant drop tensiometry.

    PubMed

    Rühs, P A; Böcker, L; Inglis, R F; Fischer, P

    2014-05-01

    Bacterial adsorption to interfaces is a key factor in biofilm formation. One major limitation to understanding biofilm formation and development is the accurate measurement of bacterial cell adhesion to hydrophobic interfaces. With this study, bacterial attachment and biofilm growth over time at water-oil interface was monitored through interfacial rheology and tensiometry. Five model bacteria (Pseudomonas putida KT2442, Pseudomonas putida W2, Salmonella typhimurium, Escherichia coli, and Bacillus subtilis) were allowed to adsorb at the water-oil interface either in their non-growing or growing state. We found that we were able to observe the initial kinetics of bacterial attachment and the transient biofilm formation at the water-oil interface through interfacial rheology and tensiometry. Electrophoretic mobility measurements and bacterial adhesion to hydrocarbons (BATH) tests were performed to characterize the selected bacteria. To validate interfacial rheology and tensiometry measurements, we monitored biofilm formation utilizing both confocal laser scanning microscopy and light microscopy. Using this combination of techniques, we were able to observe the elasticity and tension development over time, from the first bacterial attachment up to biofilm formation.

  18. Structure and charging of hydrophobic material/water interfaces studied by phase-sensitive sum-frequency vibrational spectroscopy

    PubMed Central

    Tian, C. S.; Shen, Y. R.

    2009-01-01

    We have studied the hydrophobic water/octadecyltrichlorosilane (OTS) interface by using the phase-sensitive sum-frequency vibrational spectroscopy (PS-SFVS), and we obtained detailed structural information of the interface at the molecular level. Excess ions emerging at the interface were detected by changes of the surface vibrational spectrum induced by the surface field created by the excess ions. Both hydronium (H3O+) and hydroxide (OH−) ions were found to adsorb at the interface, and so did other negative ions such as Cl−. By varying the ion concentrations in the bulk water, their adsorption isotherms were measured. It was seen that among the three, OH− has the highest adsorption energy, and H3O+ has the lowest; OH− also has the highest saturation coverage, and Cl− has the lowest. The result shows that even the neat water/OTS interface is not neutral, but charged with OH− ions. The result also explains the surprising observation that the isoelectric point appeared at ∼3.0 when HCl was used to decrease the pH starting from neat water. PMID:19706483

  19. Studying the Cost and Value of Library Services: Final Report. Technical Report APLAB/94-3/1,2,3,4.

    ERIC Educational Resources Information Center

    Kantor, Paul B.; And Others

    This is the final technical report (in three parts) of a 15-month long project to study the costs and value of library functions at five major research libraries. Twenty-one services or service aspects were studied, and numerous measures of the importance or benefit of the service to the users were made. These measures were studied together to lay…

  20. Shuttle/Agena study. Volume 2, part 2: Agena tug configurations, Shuttle/Agena interface, performance, safety, cost

    NASA Technical Reports Server (NTRS)

    1972-01-01

    An evaluation of the compatibility of the space shuttle and Agena rocket vehicle was conducted. The Agena space tug configuration design is described in terms of the total vehicle system as well as the individual subsystems and major assemblies and components. The complete interface between the Agena space tug and the space shuttle orbiter is defined for in-flight and ground operations. The derivation and design of an evolutionary stage is also presented. This vehicle conforms to the same guidelines and interface requirements as the Agena space tug. Performance data developed for both vehicles for each of the three study baseline missions are included.

  1. Study of electronic structure and magnetism at the relaxed SrTiO3/LaAlO3 interface

    NASA Astrophysics Data System (ADS)

    Ghosh, Soham; Manousakis, Efstratios

    2013-03-01

    The SrTiO3/LaAlO3 interface has been found experimentally to be metallic and magnetic, with bandstructure calculations linking both phenomena to polar catastrophe and surface oxygen vacancies. In this work, we use LDA+U to study the properties of this interface, allowing the ionic structure to be fully relaxed, and investigate the 2-dimensional nature of the electron gas formed at the junction. We present an effort to understand the role of electron-electron correlation on the interfacial collective phenomena, by constructing extended Hubbard-like models based on bandstructure calculation.

  2. Vocational-Technical and Professional Studies' Academic Programs and Support Services Self-Study and Evaluation Visit by the New Mexico Department of Education's Vocational-Technical Programs (April 17-20, 1995).

    ERIC Educational Resources Information Center

    Cowen, Sonia S.

    This report presents results from an April 1995 self-study of academic programs and support services in the vocational-technical and professional studies division at New Mexico State University's two-year branch campus at Carlsbad. College activities and outcomes are described for the following 12 programs and centers: pre-business, the Career…

  3. Study of flow at the interface of a porous medium using particle image velocimetry

    NASA Astrophysics Data System (ADS)

    Shams Saryazdi, Masoud

    This thesis reports the results of an experimental study of the flow at the interface of a fibrous porous medium and a freely flowing fluid. The model for the porous medium was a square array of parallel rods, and arrays with three different solid volume fractions were tested; namely 2.5%, 5.2%, and 10%. The flow adjacent to the porous medium was a shear flow perpendicular to the interface. It was created by generating circular Couette flow in a narrow channel outside the porous medium. Comprehensive velocity measurements were made inside and outside the various porous media using a PIV system that was developed for the experiment. An adverse pressure gradient in the streamwise direction was found to exist between the rods for the media with solid volume fractions of 5.2% and 10%. However no such pressure gradient was found for the 2.5% medium. The fluid motion corresponding to the adverse pressure gradients inside the medium was circulatory. The slip coefficient proposed by Beavers and Joseph was found directly by measuring the local velocity near the boundary of the porous medium. The slip coefficient for the media tested was found to be approximately 3. Comparisons show that Brinkman's equation in its original form (with the same viscosity inside the porous medium mu* and outside mu) did not produce results that matched the measured velocity field. Furthermore, Brinkman's equation did not produce results that matched the experimental velocity fields using any value of the viscosity ratio, mu*/mu. The measurements show that the slip velocity is small, and that Brinkman's equation with mu*/mu ≈ 9 predicts slip velocities quite well. The shear penetration length decreases as the solid volume fraction increases, and for a porous medium with a solid volume fraction of around 10%, the penetration length is smaller than all length scales of the medium. Therefore, for the higher solid volume fractions tested, shear penetration is practically negligible. Penetration of

  4. A Study of Learning-Centered Leadership Skills of Principals in Career and Technical Education Schools

    ERIC Educational Resources Information Center

    Rodman, Mary E.

    2012-01-01

    Despite years of educational reform, secondary students have demonstrated only modest increases in achievement. Career and technical education students have not demonstrated the same level of performance as non-career and technical education students. Except for teachers, principals have the greatest influence over student achievement. What should…

  5. Methodology for Planning Technical Education: With a Case Study of Polytechnics in Bangladesh.

    ERIC Educational Resources Information Center

    Ritzen, Jozef M.; Balderston, Judith B.

    A product of research first begun by one of the authors in Bangladesh, this book develops a comprehensive set of methods for planning technical education. Wherever possible, the authors draw on existing tools, fitting them to the specific context of technical education. When faced with planning problems for which existing methods are ill suited…

  6. Strategic Management for Competitive Advantage: A Case Study of Higher Technical and Vocational Education in Taiwan

    ERIC Educational Resources Information Center

    Huang, Hsun-I; Lee, Cheng-Fei

    2012-01-01

    Higher technical and vocational education institutions in Taiwan face the pressure of an oversupply of student places and fierce competition from domestic and international institutions. To cope with these challenges, higher technical and vocational education institutions that are better equipped to respond to market requirements are expected to…

  7. Design Study for Project on Standard Operating Procedures for Technical Library Services.

    ERIC Educational Resources Information Center

    Libbey, Miles A.; And Others

    The overall objective of the Technical Information Support Activities (TISA) Project is the production of a "Post Commander's Handbook." The handbook will be instrumental in achieving greater utilization of available technical information resources to assist army scientists and engineers engaged in the support of army combat and other…

  8. Technical Objects between Categorisation and Learning: An Exploratory Case Study in French Middle School

    ERIC Educational Resources Information Center

    Impedovo, M. A.; Andreucci, C.; Delserieys-Pedregosa, A.; Coiffard, C.; Ginestié, J.

    2015-01-01

    In this article we present exploratory research carried out in order to understand how students (from 12 to 14 years old) relate to technical objects. It uses technical objects that are part of everyday life and mediated reality. A questionnaire was administered to 57 students in French classes. The questionnaire was composed of three parts: 1)…

  9. X-ray photoelectron spectroscopic study of the chemical vapor deposited W/Al interface

    NASA Astrophysics Data System (ADS)

    Ohshima, H.; Katayama, M.; Onoda, K.; Hattori, T.; Suzuki, H.; Tokuda, Y.

    1993-07-01

    The dependence of the amount of aluminum trifluoride (AlF3) piled up at the interface of chemical vapor deposited tungsten and the aluminum under layer on the deposition time and subsequent annealing in ultrahigh vacuum (UHV) or in monosilane (SiH4) gas has been studied. AlF3 is formed by the reaction of the aluminum under layer with tungsten hexafluoride (WF6) during the initial state of tungsten chemical vapor deposition. Tungsten was deposited on an Al layer under selective deposition conditions by SiH4 reduction at 250 °C. X-ray photoelectron spectroscopy measurement reveals that the amount of AlF3 decreases with an increase in the tungsten deposition time and that the reduction of AlF3 by volatilization of aluminum fluorides, which occurs at higher temperatures (≳400 °C) is not observed at low temperature (270 °C). Annealing in SiH4 gas after the tungsten deposition was effective to reduce the amount of AlF3 compared with annealing in UHV. This result and thermochemical data would suggest that the dependence of the amount of AlF3 on the tungsten deposition time is explained by the reduction of AlF3 with hydrogen atoms supplied from the dissociation of SiH4.

  10. Innovative Power Wheelchair Control Interface: A Proof-of-Concept Study.

    PubMed

    Winkler, Sandra L; Romero, Sergio; Prather, Emily; Ramroop, Marisa; Slaibe, Emmy; Christensen, Matthew

    2016-01-01

    Some people without independent mobility are candidates for powered mobility but are unable to use a traditional power wheelchair joystick. This proof-of-concept study tested and further developed an innovative method of driving power wheelchairs for people whose impairments prevent them from operating commercial wheelchair controls. Our concept, Self-referenced Personal Orthotic Omni-purpose Control Interface (SPOOCI), is distinguished by referencing the control sensor not to the wheelchair frame but instead to the adjacent proximal lower-extremity segment via a custom-formed orthosis. Using a descriptive case-series design, we compared the pre-post functional power wheelchair driving skill data of 4 participants, measured by the Power Mobility Program, using descriptive analyses. The intervention consisted of standard-care power wheelchair training during 12 outpatient occupational or physical therapy sessions. All 4 participants who completed the 12-wk intervention improved their functional power wheelchair driving skills using SPOOCI, but only 3 were deemed safe to continue with power wheelchair driving.

  11. [Time-resolved optical studies of charge relaxation and charge transfer at electrode interfaces

    SciTech Connect

    Not Available

    1992-01-01

    Key components were identified in a quantitative model of carrier relaxation in semiconductor electrodes: nonlinear aspects of nonradiative and radiative recombination, effect of space charge field on carrier dynamics, self-absorption effects in direct gas semiconductors, and influence of surface state population kinetics on charge carrier recombination. For CdSe, the first three are operative (no direct proof of the last one). A realistic kinetic model for carrier recombination in the bulk of CdSe was used which includes important nonlinear effects, both radiative and nonradiative. The change in interfacial recombination velocity with the chemical nature of the sinterface was studied (n-CdSe/silane interfaces). Temperature effect (278 to 328 K) on fluorescence decay of n-CdSe in contact with 0.5 M KOH was found to be weak. An analytical solution was obtained for time-resolved fluoresence from electrodes under potential bias, and is being tested. Fluorescence work on a different material, CdS, indicate different recombination kinetics; this material was used to directly pump an optical transition of a surface state.

  12. [Time-resolved optical studies of charge relaxation and charge transfer at electrode interfaces

    SciTech Connect

    Not Available

    1992-12-31

    Key components were identified in a quantitative model of carrier relaxation in semiconductor electrodes: nonlinear aspects of nonradiative and radiative recombination, effect of space charge field on carrier dynamics, self-absorption effects in direct gas semiconductors, and influence of surface state population kinetics on charge carrier recombination. For CdSe, the first three are operative (no direct proof of the last one). A realistic kinetic model for carrier recombination in the bulk of CdSe was used which includes important nonlinear effects, both radiative and nonradiative. The change in interfacial recombination velocity with the chemical nature of the sinterface was studied (n-CdSe/silane interfaces). Temperature effect (278 to 328 K) on fluorescence decay of n-CdSe in contact with 0.5 M KOH was found to be weak. An analytical solution was obtained for time-resolved fluoresence from electrodes under potential bias, and is being tested. Fluorescence work on a different material, CdS, indicate different recombination kinetics; this material was used to directly pump an optical transition of a surface state.

  13. Innovative Power Wheelchair Control Interface: A Proof-of-Concept Study

    PubMed Central

    Romero, Sergio; Prather, Emily; Ramroop, Marisa; Slaibe, Emmy; Christensen, Matthew

    2016-01-01

    Some people without independent mobility are candidates for powered mobility but are unable to use a traditional power wheelchair joystick. This proof-of-concept study tested and further developed an innovative method of driving power wheelchairs for people whose impairments prevent them from operating commercial wheelchair controls. Our concept, Self-referenced Personal Orthotic Omni-purpose Control Interface (SPOOCI), is distinguished by referencing the control sensor not to the wheelchair frame but instead to the adjacent proximal lower-extremity segment via a custom-formed orthosis. Using a descriptive case-series design, we compared the pre–post functional power wheelchair driving skill data of 4 participants, measured by the Power Mobility Program, using descriptive analyses. The intervention consisted of standard-care power wheelchair training during 12 outpatient occupational or physical therapy sessions. All 4 participants who completed the 12-wk intervention improved their functional power wheelchair driving skills using SPOOCI, but only 3 were deemed safe to continue with power wheelchair driving. PMID:26943118

  14. Photoemission Spectroscopy Studies of Methylammonium Lead Iodide Perovskite Thin Films and Interfaces

    NASA Astrophysics Data System (ADS)

    Thibau, Emmanuel S.

    Organometal halide perovskites have recently emerged as promising materials for fundamentally low-cost, high-performance optoelectronics. In this thesis, we utilize thermal co-evaporation of PbI2 and CH3NH 3 I to fabricate thin films of CH3NH3PbI 3. We first investigate the effect of stoichiometry on some of its structural, optical and electronic properties. Then, we study the energy level alignment of CH3NH3PbI3 with 6 organic semiconductors, revealing good agreement between the data and the theory of vacuum level alignment. Finally, the interface formed between CH3NH 3PbI3 and MoO3 is examined. The findings suggest migration of iodide species into the oxide layer, resulting in deterioration of its chemical and electronic properties. Insertion of an organic interlayer is shown to mitigate these undesirable effects. The results of this work could be of use in device engineering, where knowledge of such interfacial phenomena is of utmost importance in achieving optimized device structures.

  15. Interface between C60 and Ag on nanostructured plasmonic Ag gratings: A SERS study

    NASA Astrophysics Data System (ADS)

    Khosroabadi, Akram A.; Matz, Dallas L.; Gangopadhyay, Palash; Pemberton, Jeanne E.; Norwood, Robert A.

    2013-09-01

    Nanostructured electrodes and interfaces can enhance light absorption in organic solar cells due to efficient light harvesting. Ultrathin films of an active layer (C60) deposited on nanostructured grating electrodes show more absorption as a result of increased light trapping. Plasmonic nanostructured electrodes with various geometries and dimensions have been fabricated on printed polyacrylonitrile (PAN) and subsequently characterized. Surface enhanced Raman scattering (SERS) measurements show significant signal enhancement (over two orders of magnitude) on nanostructured samples when compared to planar Ag substrates due to local electromagnetic field enhancement. Furthermore, conversion of PAN to graphitic carbon is evidenced in SERS spectra. The surface area was determined using underpotential deposition (UPD) of thallium and agrees with the geometric surface area calculated from SEM images. The FDTD simulated electric field distribution inside the samples confirms the experimental results. A 60 fold increase in the electric field results in three to four orders of magnitude enhancement in the SERS signal depending on the dimensions of the pillars and gratings. Further study of the interaction between a top organic layer (C60) and the Ag electrode will help us to understand the nanoscale charge transfer rate critical to optimization and design of efficient organic solar cells.

  16. Studies on the adsorption of Brij-35 and CTAB at the coal-water interface.

    PubMed

    Mishra, S K; Panda, D

    2005-03-15

    The adsorption behavior of polyoxyethylene (23) lauryl ether (Brij-35) and cetyl trimethyl ammonium bromide (CTAB) on coal sample has been studied. The adsorption process is found to be sensitive to pH, temperature, electrolyte concentration, and the amount of surface active agent. An attempt has been made to explain the adsorption behavior of the surfactants using the Langmuir equation. The extent of adsorption of Brij-35 on coal is found to be the highest at pH 2, which decreases with increase in pH and remains constant in the neutral and alkaline pH regions. But, the adsorption of CTAB exhibits the opposite behavior of that of Brij-35. Adsorption of any of the surfactant at the coal/water interface sharply decreases the apparent viscosity of 55 wt% coal-water slurry (CWS) at a shear rate of 100 s(-1). Electrostatic adsorption of the surfactants on the coal surface decreases the surface charge and renders the coal surface hydrophobic which is manifested in the form of high apparent viscosity of the coal-water slurry under the test conditions.

  17. [A study of brain-computer interface paradigm based on mental arithmetic].

    PubMed

    Wang, Luzhou; Wang, Suogang; Kuang, Guangtao

    2013-06-01

    In the traditional P300 brain-computer interface (BCI) system, the electroencephalogram (EEG) signals can only provide limited information with a low signal-to-noise ratio. A BCI paradigm under visual stimulus was proposed in our study aiming to effectively activate the related brain areas and response signal while dealing with specific cognitive task (mental arithmetic task), so as to enhance the EEG signals. The result was compared with the traditional P300 counting task paradigm. Then the collected EEG data were preprocessed including extracting signal features with coherent averaging method, and analyzing the influences of different experimental paradigms on main components of event related potential (ERP). In the improved paradigm experiments the average increasing rate of P300 amplitude was 6. 83MV (73. 94%). The brain activity from 400ms was more active and lasted longer. Besides, unlike traditional counting task, mental arithmetic task appeared to have apparent activation at 650ms. The results showed that the improved paradigm could activate the related brain areas better and enhance the characteristics of signal. This provides a new system paradigm for BCI.

  18. Molecular Dynamics Study of the Electrical Double Layer at Silver Chloride Electrolyte Interfaces

    SciTech Connect

    Zarzycki, Piotr P.; Kerisit, Sebastien N.; Rosso, Kevin M.

    2010-05-20

    Molecular dynamics simulations of the electrical double layer at AgCl/aqueous electrolyte (KCl) interfaces are presented, accompanied by a new force field and properties of bulk AgCl computed using planewave density functional theory. Long dynamics simulations were performed to estimate ion adsorption free energies at the AgCl surface. The simulations demonstrate formation of a bilayer hydration sheet composed of two sublayers of water molecules interconnected by hydrogen bonds. Potassium ions prefer to form an inner-sphere complex, whereas chloride ions prefer outer-sphere complexes. The adsorbed ions/water layers form a relatively rigid structure within the range of ionic strength considered, which confirms the applicability of the Helmholtz model in a high concentration regime. Profiles of the charge density, electric field and electrostatic potential across the simulation cell revealed that oscillations of water molecules govern these quantities. The electrostatic potential generated only by the electrolyte ions was used to study the quasi-Nernstian response of the silver chloride surface to the variation in the ionic strength.

  19. Study of interface mixing induced by Ar+ ion irradiation on Ag-Ge bilayer system

    NASA Astrophysics Data System (ADS)

    Nawash, J. M.; Masoud, N. M.; Al-Saleh, K. A.; Saleh, N. S.

    2009-11-01

    A 400 keV 40Ar+ ion beam was utilized to induce mixing between two thin layers of Ag and Ge. Rutherford Backscattering Spectrometry and Electrical Resistivity Measurements were employed as probes to investigate the kinetics of ion mixing. The intermixed region was studied at several fluences up to 1.7×1017 ions/cm2 at a constant flux of 0.25 μA/cm2. The “RUMP” simulation computer code was used to assist in the evaluation of the experimental results from the spectra. The analysis of the Rutherford Backscattering Spectrometry spectra shows that increasing the Ar+ fluence enhances the Ag-Ge intermixing. To describe the mixing process, mixing rate parameters were calculated and compared with the theoretical models’ predictions. Børgesen’s local thermal spike model was found to accurately predict the diffusion in the Ag-Ge interface. An increase in the electrical resistivity of the film was detected during irradiation.

  20. Study of dithiol monolayer as the interface for controlled deposition of gold nanoparticles

    SciTech Connect

    Cichomski, M.; Tomaszewska, E.; Kosla, K.; Kozlowski, W.; Grobelny, J.

    2011-03-15

    Self-assembled monolayer of dithiol molecules, deposited on polycrystalline Au (111), prepared at room atmosphere, was studied using scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). Dithiols were used as interface, which chemically bonds to the deposited gold nanoparticles through strong covalent bonds. The size and size distribution of the deposited nanoparticles were measured using dynamic light scattering (DLS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The AFM results showed that nanoparticles are immobilized and stable during scanning procedure and do not contaminate the AFM tip. The size of monodisperse nanoparticles obtained from the DLS measurements is slightly higher than that obtained from the AFM and SEM measurements. This is due to the fact that the DLS measures the hydrodynamic radius, dependent on the protective chemical layer on nanoparticles. - Research Highlights: {yields} Dithiols molecules create chemically bounded layers on a Au (111) surface. {yields} Gold nanoparticles can be chemically bounded to a self-assembled monolayer. {yields} Nanoparticles are stable during AFM probe interactions.

  1. Open, microfluidic flow cell for studies of interfacial processes at gas-liquid interfaces.

    PubMed

    Hoang, Khanh C; Malakhov, Dmitry; Momsen, William E; Brockman, Howard L

    2006-03-01

    Interfacial processes involving peripheral proteins depend on the composition and packing density of the interfacial lipid molecules. As a biological membrane model, lipid monolayers at the gas-liquid interface allow independent control of these parameters. However, measuring protein adsorption to monolayers has been difficult. To aid in this and other studies of the interfacial processes, we have developed an open, microfluidic flow cell with which surface physical properties can be controlled and monitored in well-defined lipid monolayers while varying aqueous-phase composition. Using this apparatus, we implement a recently described fluorescence method (Momsen, W. E.; Mizuno, N. K.; Lowe, M. E.; Brockman, H. L. Anal. Biochem. 2005, 346, 139-49) to characterize the adsorption/desorption of glucagon to 1,2-dioleoyl-sn-glycerol monolayers at 27 mN/m. Analysis of the data gives reasonable and self-consistent results for kinetic and thermodynamic constants. Varying the packing density of 1,2-dioleoyl-sn-glycerol does not alter the extent of glucagon adsorption, but comparable measurements with 1-steaoryl-2-oleoyl-sn-glycero-3-phosphocholine show a critical dependence. Because it allows a high degree of control of both lipid monolayer properties and aqueous-phase composition, this microfluidic flow cell should find wide applicability in many areas of research into interfacial processes.

  2. Density-Functional Study of the Two-Dimensional Electron Gas at the Perovskite Titanate Interface

    NASA Astrophysics Data System (ADS)

    Nanda, Ranjit; Popovic, Zoran; Thulasi, Sunita; Satpathy, Sashi

    2006-03-01

    Oxide superlattices and microstructures hold the promise for creating a new class of devices with unprecedented functionalities. Density-functional studies^1 of the recently fabricated, lattice-matched perovskite titanates^2 (SrTiO3)n/(LaTiO3)m reveal a classic wedge-shaped potential well for the monolayer structure, originating from the Coulomb potential of a charged La sheet. The potential in turn confines the electrons in the Airy-function-localized states. This resulting two-dimensional electron gas may be described in terms of the simplified jellium model^3 and it describes reasonably well the observed charge modulation of the Ti atoms near the interface. Concerning magnetism, it is suppressed for the monolayer LaTiO3 structure, while in structures with a thicker LaTiO3 part, bulk antiferromagnetism is recovered, with a narrow transition region separating the magnetic LaTiO3 and the non-magnetic SrTiO3. 1. Z. S. Popovic and S. Satpathy, Phys. Rev. Lett. 94, 176805 (2005) 2. A. Ohtomo et al., Nature 419, 378 (2002) 3. S. Thulasi and S. Satpathy, Phys. Rev. B (2006)

  3. Mutagenesis study to disrupt electrostatic interactions on the twofold symmetry interface of Escherichia coli bacterioferritin.

    PubMed

    Zhang, Yu; Wang, Lijun; Ardejani, Maziar S; Aris, Nur Fazlina; Li, Xun; Orner, Brendan P; Wang, Fei

    2015-12-01

    Ferritins and other cage proteins have been utilized as models to understand the fundamentals of protein folding and self-assembly. The bacterioferritin (BFR) from Escherichia coli, a maxi-ferritin made up of 24 subunits, was chosen as the basis for a mutagenesis study to investigate the role of electrostatic intermolecular interactions mediated through charged amino acids. Through structural and computational analyses, three charged amino acids R30, D56 and E60 which involved in an electrostatic interaction network were mutated to the opposite charge. Four mutants, R30D, D56R, E60H and D56R-E60H, were expressed, purified and characterized. All of the mutants fold into α-helical structures. Consistent with the computational prediction, they all show a lowered thermostability; double mutant D56R-E60H was found to be 16°C less stable than the wild type. Except for the mutant E60H, all the other mutations completely shut down the formation of protein cages to favour the dimer state in solution. The mutants, however, retain their ability to form cage-like nanostructures in the dried, surface immobilized conditions of transmission electron microscopy. Our findings confirm that even a single charge-inversion mutation at the 2-fold interface of BFR can affect the quaternary structure of its dimers and their ability to self-assemble into cage structures.

  4. Study of interface interactions in ZnO/Mesoporous silica nanocomposite

    NASA Astrophysics Data System (ADS)

    Reddy A, R. C.; Babu K, Sowri; Ch, Sujatha; Reddy K, V. G.

    2012-02-01

    The Photoluminescence (PL) properties of ZnO/Mesoporous silica (MPS) nanocomposite annealed under different temperatures were studied. A broad PL band at 395 nm has been observed in all samples and analysis was made by using Gaussian fitting. As the temperature increased, emission bands were blue shifted and the relative intensity ratio of the oxygen vacancies at ZnO-SiO2 interface to the oxygen vacancies in inner ZnO crystallites was increased. The emission peaks at 363 nm and 384 nm are attributed to the near band edge emission (NBE) and to the phonon replica emission. At 550C the exciton confinement effect disappears due to the large amount of surface effects. The influence of porosity of host media on Si-O-Zn cross linking bonds was also investigated. ZnO nanoparticles were loaded into nanocrystalline silica (NCS) and silica gel (SG). The surface area increases monotonously from NCS to MPS through SG. Si-O-Zn cross linking bonds were almost absent in the sample prepared with NCS. It exhibits NBE emission at 360 nm which was found to be absent in other samples prepared with SG and MPS. It was also found that the emission intensity of the samples decreases with aging. This is due to diffusion of oxygen atoms from the atmosphere to interior of the sample.

  5. Using minimal human-computer interfaces for studying the interactive development of social awareness

    PubMed Central

    Froese, Tom; Iizuka, Hiroyuki; Ikegami, Takashi

    2014-01-01

    According to the enactive approach to cognitive science, perception is essentially a skillful engagement with the world. Learning how to engage via a human-computer interface (HCI) can therefore be taken as an instance of developing a new mode of experiencing. Similarly, social perception is theorized to be primarily constituted by skillful engagement between people, which implies that it is possible to investigate the origins and development of social awareness using multi-user HCIs. We analyzed the trial-by-trial objective and subjective changes in sociality that took place during a perceptual crossing experiment in which embodied interaction between pairs of adults was mediated over a minimalist haptic HCI. Since that study required participants to implicitly relearn how to mutually engage so as to perceive each other's presence, we hypothesized that there would be indications that the initial developmental stages of social awareness were recapitulated. Preliminary results reveal that, despite the lack of explicit feedback about task performance, there was a trend for the clarity of social awareness to increase over time. We discuss the methodological challenges involved in evaluating whether this trend was characterized by distinct developmental stages of objective behavior and subjective experience. PMID:25309490

  6. Waste-to-energy plant for paper industry sludges disposal: technical-economic study.

    PubMed

    Caputo, A C; Pelagagge, P M

    2001-02-16

    In this work, a detailed technical-economic analysis of a fluidized bed based waste-to-energy system for disposal of paper manufacturing sludges has been carried out. Specific reference is made to a case study represented by the largest plant in Italy producing recycled paper, with a daily sludge output of about 52t. The adopted plant has been sized for a nominal capacity of 140t per day also allowing the progressive elimination of sludges accumulated in a previously utilized landfill, giving a nominal electrical power output of 3.5MW. The main plant sections have been described and the adopted technical solutions have been outlined. A detailed process and equipment characterization has been carried out leading to a thorough evaluation of capital investment, operating costs and revenues. A differential analysis has been performed with respect to the alternative solution represented by the disposal of untreated sludges in an external landfill in order to highlight the savings obtainable. The economic profitability of the investment has been evaluated regarding several performance indices. The economic evaluation has been completed by a sensitivity and risk analysis in order to assess the effects of uncertainties in the economically significant parameters. Adopting most probable values, the savings obtained with the considered waste-to-energy system are evaluated in the 15--20 million Euro range during the estimated plant life of 15 years with a foreseen pay back time of 4 years. Moreover, many environmental benefits result such as the remediation of existing landfill, the avoidance of new landfills opening and very low air pollutants emissions.

  7. A Case Study of the Usability Testing of the University of South Florida's Virtual Library Interface Design.

    ERIC Educational Resources Information Center

    Allen, Maryellen

    2002-01-01

    Discussion of usability testing of Web interfaces for virtual libraries focuses on a usability study conducted at the University of South Florida. Highlights include testing instruments; discrepancies between actual performance and perceived performance; and the need to use plainer language and less jargon. (LRW)

  8. An Exploratory Study of Video Browsing User Interface Designs and Research Methodologies: Effectiveness in Information Seeking Tasks.

    ERIC Educational Resources Information Center

    Tse, Tony; Vegh, Sandor; Shneiderman, Ben; Marchionini, Gary

    1999-01-01

    The purpose of this exploratory study was to develop research methods to compare the effectiveness of two video browsing interface designs, or surrogates--one static (storyboard) and one dynamic (slide show)--on two distinct information seeking tasks (gist determination and object recognition). (AEF)

  9. A Study of a Direct Interface of the Novice User To a Complex Batch Processed Computer Application.

    ERIC Educational Resources Information Center

    Link, Albert D.

    A research study investigated the validity of directly interfacing an uninitiated user with a complex, computerized batch processing system via a conversational, interactive language. A control group conducted mediated searches of the Educational Resources Information Center's (ERIC) files by consulting with an information specialist. Members of…

  10. Quartz crystal microbalance: a useful tool for studying thin polymer films and complex biomolecular systems at the solution-surface interface.

    PubMed

    Marx, Kenneth A

    2003-01-01

    The quartz crystal microbalance (QCM) is a simple, cost effective, high-resolution mass sensing technique, based upon the piezoelectric effect. As a methodology, the QCM evolved a solution measurement capability in largely analytical chemistry and electrochemistry applications due to its sensitive solution-surface interface measurement capability. The technique possesses a wide detection range. At the low mass end, it can detect monolayer surface coverage by small molecules or polymer films. At the upper end, it is capable of detecting much larger masses bound to the surface. These can be complex arrays of biopolymers and biomacromolecules, even whole cells. In addition, the QCM can provide information about the energy dissipating properties of the bound surface mass. Another important and unique feature of the technique is the ability to measure mass and energy dissipation properties of films while simultaneously carrying out electrochemistry on solution species or upon film systems bound to the upper electrode on the oscillating quartz crystal surface. These measurements can describe the course of electropolymerization of a film or can reveal ion or solute transport within a film during changes in the film environment or state, including the oxidation state for an electroactive film driven by the underlying surface potential. The past decade has witnessed an explosive growth in the application of the QCM technique to the study of a wide range of molecular systems at the solution-surface interface, in particular, biopolymer and biochemical systems. In this report, we start with a brief historical and technical overview. Then we discuss the application of the QCM technique to measurements involving micellar systems, self-assembling monolayers and their phase transition behavior, molecularly imprinted polymers, chemical sensors, films formed using the layer-by-layer assembly technique, and biopolymer films and point out the utility of the electrochemical

  11. Technical note: Detection of dimethylamine in the low pptv range using nitrate Chemical Ionization-Atmospheric Pressure interface-Time Of Flight (CI-APi-TOF) mass spectrometry

    NASA Astrophysics Data System (ADS)

    Simon, M.; Heinritzi, M.; Herzog, S.; Leiminger, M.; Bianchi, F.; Praplan, A.; Dommen, J.; Curtius, J.; Kürten, A.

    2015-12-01

    Amines are potentially important for atmospheric new particle formation and therefore the demand for highly sensitive gas phase amine measurements has emerged in the last several years. Nitrate Chemical Ionization Mass Spectrometry (CIMS) is routinely used for the measurement of gas phase-sulfuric acid in the sub-pptv range. Furthermore, Extremely Low Volatile Organic Compounds (ELVOCs) can be detected with a nitrate CIMS. In this study we demonstrate that a nitrate CIMS can also be used for the sensitive measurement of dimethylamine ((CH3)2NH, DMA) using the NO3-(HNO3)1-2(DMA) cluster ion signals. This observation was made at the CLOUD aerosol chamber, which was also used for calibration measurements. Good linearity between 0 and ~120 pptv of DMA as well as a sub-pptv detection limit of 0.7 pptv for a 10 min integration time are demonstrated at 278 K and 38 % RH.

  12. Technical Design and Optimization Study for the FERMI@Elettra FELPhotoinjector

    SciTech Connect

    Lidia, Steven M.; Penco, Giuseppe; Trovo', Mauro

    2006-06-30

    The FERMI {at} Elettra FEL project will provide a novel, x-ray free electron laser user facility at Sincrotrone Trieste based on seeded and cascade FEL techniques. The electron beam source and injector systems play a crucial role in the success of the facility by providing the highest quality electron beams to the linac and FEL undulators. This Technical Note examines the critical technology components that make up the injector system, and demonstrates optimum beam dynamics solutions to achieve the required high quality electron beams. Section 2 provides an overview of the various systems and subsystems that comprise the photoinjector. The different operating modes of the injector are described as they pertain to the different linac configurations driven by the FEL and experimental design. For each mode, the required electron beam parameters are given. Sections 3 and 4 describe the critical beamline elements in the injector complex: the photocathode and drive laser, and the RF gun. The required drive laser parameters are given at the end of Section 3. Additional details on the design of the photoinjector drive laser systems are presented in a separate Technical Note. Design considerations for the RF gun are extensively presented in Section 4. There, we describe the variation of the cavity geometry to optimize the efficiency of the energy transfer to the electron beam. A study of the power coupling into the various cavity modes that interact within the bandwidth of the RF drive pulse is presented, followed by a study of the transient cavity response under several models and, finally, the effects on extracted beam quality. Section 5 describes the initial design for the low energy, off-axis diagnostic beamline. Beam dynamics simulations using ASTRA, elegant, and MAD are presented. Section 6 presents the optimization studies for the beam dynamics in the various operating modes. The optimized baseline configurations for the beamline and incident drive laser pulse are

  13. Molecular Dynamics Studies on Liquid/vapor Interface Properties and Structures of 1-Ethyl-3-Methylimidazolium Dimethylphosphate-Water.

    PubMed

    Li, Tianyu; Zhao, Zongchang; Zhang, Xiaodong; Sun, Xican

    2017-03-20

    1-ethyl-3-methylimidazolium dimethylphosphate ([Emim][Dmp])-water binary solution is one of the promising new working-pairs for absorption heat pump and absorption chillers, which are widely used to recover industrial waste heat. In the absorption process, the mass and heat transfer at the interface greatly depend on interface microscopes structure. Therefore, in order to understand the absorption process, it is very important to study the interface microscopes structure. The liquid-vapor interface properties, as well as the orientation of [Emim]+, [Dmp]-, water at the interface and its aqueous solution with different water mole fraction, were studied using classical all-atom force field by molecular dynamic simulations. The simulated bulk mass density fitted by hyperbolic tangent function for each system was in good agreement with the experiment data, with the relative deviation between simulated and experimental value within 2%. The simulated results indicate that anion is always distributed at the outmost layer of the interface, followed by cation and water molecule. In [Emim][Dmp], the tilt angle of imidazolium rings to the surface normal is in the range of 0º<θ<12º; for most cation, their ethyl and methyl tilted towards gas phase and bulk respectively, but for a few cation, their ethyl and the methyl take the opposite orientation. For anion, one methyl prefers to turn towards gas phase and another methyl (PC vector from P atom to C atom) lie nearly parallel to the surface, while one PO vector (from P atom to O atom) turns towards liquid bulk and another PO vector is nearly parallel to the surface. In aqueous solution of [Emim][Dmp], the tilt angle of the imidazolium ring to the surface normal becomes larger (0º<θ<37º) at the interface, but almost all ethyl intend to tilt towards gas phase and the methyl tilt towards liquid bulk compared with pure [Emim][Dmp]. Two methyl in anion prefer to turn towards gas phase and its two PO vectors towards liquid bulk

  14. National Institute of Statistical Sciences Configuration and Data Integration for Longitudinal Studies Technical Panel. Final Report. NCES 2011-607

    ERIC Educational Resources Information Center

    Karr, Alan F.

    2011-01-01

    This is the final report of the National Institute of Statistical Sciences (NISS) Technical Panel on Configuration and Data Integration for Longitudinal Studies (hereafter, CDI). The principal recommendations regarding configuration are as follows: (1) The National Center for Education Statistics (NCES) should configure grades K-12 studies as a…

  15. Teacher Quality Partnership Novice Teacher Studies Technical Report NTS 10-01 Research Brief 2007-2009

    ERIC Educational Resources Information Center

    Kinnucan-Wesch, Kathryn; Franco, Suzanne; Hendricks, Martha S.

    2010-01-01

    The purpose of this technical report is to summarize the research methodology of the Novice Teacher Study (NTS) strand of the Teacher Quality Partnership (TQP) research. The Ohio TQP has embarked on a series of research studies to learn more about the characteristics of effective teachers and to identify the patterns of teacher performance in both…

  16. A Case Study of an Ameliorable Career/Technical School: An Exploration of Principal/Teacher Relationships

    ERIC Educational Resources Information Center

    Glover, Joan

    2012-01-01

    This participatory action research study explored principal/teacher relationships in an ameliorable career/technical school located in the mid-west United States. This study examined how teachers in this school perceive their relationship with the principal and how a principal perceives her relationship with the teachers. This empirical inquiry…

  17. Learning and Collaboration in Professional Development for Career and Technical Education Teachers: A Qualitative Multi-Case Study

    ERIC Educational Resources Information Center

    Sturko, Patricia A.; Gregson, James A.

    2009-01-01

    This multi-case study explored the learning and collaboration of six Career and Technical Education (CTE) teachers in two different types of professional development experiences: (a) a course on integrating reading, writing, and mathematics skills into CTE curricula, delivered by a master teacher; and (b) a small teacher study group that met…

  18. Milk whey proteins and xanthan gum interactions in solution and at the air-water interface: a rheokinetic study.

    PubMed

    Perez, Adrián A; Sánchez, Cecilio Carrera; Patino, Juan M Rodríguez; Rubiolo, Amelia C; Santiago, Liliana G

    2010-11-01

    In this contribution, we present experimental information about the effect of xanthan gum (XG) on the adsorption behaviour of two milk whey protein samples (MWP), beta-lactoglobulin (beta-LG) and whey protein concentrate (WPC), at the air-water interface. The MWP concentration studied corresponded to the protein bulk concentration which is able to saturate the air-water interface (1.0 wt%). Temperature, pH and ionic strength of aqueous systems were kept constant at 20 degrees C, pH 7 and 0.05 M, respectively, while the XG bulk concentration varied in the range 0.00-0.25 wt%. Biopolymer interactions in solution were analyzed by extrinsic fluorescence spectroscopy using 1-anilino-8-naphtalene sulphonic acid (ANS) as a protein fluorescence probe. Interfacial biopolymer interactions were evaluated by dynamic tensiometry and surface dilatational rheology. Adsorption behaviour was discussed from a rheokinetic point of view in terms of molecular diffusion, penetration and conformational rearrangement of adsorbed protein residues at the air-water interface. Differences in the interaction magnitude, both in solution and at the interface vicinity, and in the adsorption rheokinetic parameters were observed in MWP/XG mixed systems depending on the protein type (beta-LG or WPC) and biopolymer relative concentration. beta-LG adsorption in XG presence could be promoted by mechanisms based on biopolymer segregative interactions and thermodynamic incompatibility in the interface vicinity, resulting in better surface and viscoelastic properties. The same mechanism could be responsible of WPC interfacial adsorption in the presence of XG. The interfacial functionality of WPC was improved by the synergistic interactions with XG, although WPC chemical complexity might complicate the elucidation of molecular events that govern adsorption dynamics of WPC/XG mixed systems at the air-water interface.

  19. Precision of a needle localization technic in the lumbosacral multifidus muscles for segmental specific needle electromyographic study: a cadaveric study.

    PubMed

    Chinsethagij, Kosum; Wongphaet, Parit; Su-archawaratana, Siripim; Dangprasert, Tanyarat

    2003-08-01

    The authors studied 14 cadavers to evaluate the claimed precision of needle placement into segment specific multifidus fascicles when using the "paraspinal mapping" electromyographic technic. Injection of acrylic dye was made according to landmarks proposed by Haig. The dissection showed 86.6 per cent of the injected dye in the correct fascicles. Only 1.4 per cent of the dye was lost. Spinous process level misidentification was the cause of the other 11.8 per cent incorrect injection. The authors expected that in living humans, in which the spinous processes are move identificable than embalmed cadavers, the precisions may be as high as 98.5 per cent. This remains to be studied in a further "in vivo" study.

  20. Ultrafast optical studies of surface reaction processes at semiconductor interfaces. Progress report

    SciTech Connect

    Miller, R.J.D.

    1994-10-01

    The DOE funded research has focused on the development of novel non-linear optical methods for the in situ study of surface reaction dynamics. In particular, the work has concentrated on interfacial charge transfer processes as this is the simplest of all surface reactions, i.e., no bonds are broken and the reaction is derived from nuclear repolarization. Interfacial charge transfer forms the basis for a number of important solar energy conversion strategies. In these studies, semiconductor liquid junctions provide a convenient system in which the interfacial charge transfer can be optically initiated. The all-optical approach necessitates that the dynamics of the charge transfer event itself be put in the proper context of the operating photophysical processes at the surface. There are at least four dynamical processes that are coupled in determining the overall rate of electron flux across the interface. In the limit that interfacial charge transfer approaches strong coupling, the time scale for transport of even field accelerated carriers within the space charge region becomes comparable to the charge transfer dynamics. The transport component needs to be convolved to probes of the carrier population at the surface. The other two dynamical processes, carrier thermalization and surface state trapping, determine the states which ultimately serve as the donor levels to the solution acceptor distribution. In terms of the hot carrier model, these latter two processes compete with direct unthermalized charge transfer. There is a fifth dynamical process which also needs consideration: the solvent modes that are coupled to the reaction coordinate. Ultimately, the dynamics of solvent relaxation determine the upper limit to the charge transfer process. Different optical techniques have been developed to follow all the above dynamical processes in which a real time view of charge transfer dynamics at semiconductor surfaces is emerging. These results are discussed here.

  1. Wildfire risk in the wildland-urban interface: A simulation study in northwestern Wisconsin

    USGS Publications Warehouse

    Massada, Avi Bar; Radeloff, Volker C.; Stewart, Susan I.; Hawbaker, Todd J.

    2009-01-01

    The rapid growth of housing in and near the wildland–urban interface (WUI) increases wildfirerisk to lives and structures. To reduce fire risk, it is necessary to identify WUI housing areas that are more susceptible to wildfire. This is challenging, because wildfire patterns depend on fire behavior and spread, which in turn depend on ignition locations, weather conditions, the spatial arrangement of fuels, and topography. The goal of our study was to assess wildfirerisk to a 60,000 ha WUI area in northwesternWisconsin while accounting for all of these factors. We conducted 6000 simulations with two dynamic fire models: Fire Area Simulator (FARSITE) and Minimum Travel Time (MTT) in order to map the spatial pattern of burn probabilities. Simulations were run under normal and extreme weather conditions to assess the effect of weather on fire spread, burn probability, and risk to structures. The resulting burn probability maps were intersected with maps of structure locations and land cover types. The simulations revealed clear hotspots of wildfire activity and a large range of wildfirerisk to structures in the study area. As expected, the extreme weather conditions yielded higher burn probabilities over the entire landscape, as well as to different land cover classes and individual structures. Moreover, the spatial pattern of risk was significantly different between extreme and normal weather conditions. The results highlight the fact that extreme weather conditions not only produce higher fire risk than normal weather conditions, but also change the fine-scale locations of high risk areas in the landscape, which is of great importance for fire management in WUI areas. In addition, the choice of weather data may limit the potential for comparisons of risk maps for different areas and for extrapolating risk maps to future scenarios where weather conditions are unknown. Our approach to modeling wildfirerisk to structures can aid fire risk reduction management

  2. Alignment control and atomically-scaled heteroepitaxial interface study of GaN nanowires.

    PubMed

    Liu, Qingyun; Liu, Baodan; Yang, Wenjin; Yang, Bing; Zhang, Xinglai; Labbé, Christophe; Portier, Xavier; An, Vladimir; Jiang, Xin

    2017-04-11

    Well-aligned GaN nanowires are promising candidates for building high-performance optoelectronic nanodevices. In this work, we demonstrate the epitaxial growth of well-aligned GaN nanowires on a [0001]-oriented sapphire substrate in a simple catalyst-assisted chemical vapor deposition process and their alignment control. It is found that the ammonia flux plays a key role in dominating the initial nucleation of GaN nanocrystals and their orientation. Typically, significant improvement of the GaN nanowire alignment can be realized at a low NH3 flow rate. X-ray diffraction and cross-sectional scanning electron microscopy studies further verified the preferential orientation of GaN nanowires along the [0001] direction. The growth mechanism of GaN nanowire arrays is also well studied based on cross-sectional high-resolution transmission electron microscopy (HRTEM) characterization and it is observed that GaN nanowires have good epitaxial growth on the sapphire substrate following the crystallographic relationship between (0001)GaN∥(0001)sapphire and (101[combining macron]0)GaN∥(112[combining macron]0)sapphire. Most importantly, periodic misfit dislocations are also experimentally observed in the interface region due to the large lattice mismatch between the GaN nanowire and the sapphire substrate, and the formation of such dislocations will favor the release of structural strain in GaN nanowires. HRTEM analysis also finds the existence of "type I" stacking faults and voids inside the GaN nanowires. Optical investigation suggests that the GaN nanowire arrays have strong emission in the UV range, suggesting their crystalline nature and chemical purity. The achievement of aligned GaN nanowires will further promote the wide applications of GaN nanostructures toward diverse high-performance optoelectronic nanodevices including nano-LEDs, photovoltaic cells, photodetectors etc.

  3. Earth Observatory Satellite system definition study. Report no. 2: Instrument constraints and interface specifications

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The instruments to be flown on the Earth Observatory Satellite (EOS) system are defined. The instruments will be used to support the Land Resources Management (LRM) mission of the EOS. Program planning information and suggested acquisition activities for obtaining the instruments are presented. The subjects considered are as follows: (1) the performance and interface of the Thematic Mapper (TM) and the High Resolution Pointing Imager (HRPI), (2) procedure for interfacing the TM and HRPI with the EOS satellite, (3) a space vehicle integration plan suggesting the steps and sequence of events required to carry out the interface activities, and (4) suggested agreements between the contractors for providing timely and equitable solution of problems at minimum cost.

  4. Molecular Dynamics Studies of Structure and Functions of Water-Membrane Interfaces

    NASA Technical Reports Server (NTRS)

    Pohorille, Andrew; Wilson, Michael A.; DeVincenzi, Donald L. (Technical Monitor)

    2001-01-01

    A large number of essential cellular processes occur at the interfaces between water and membranes. The selectivity and dynamics of these processes are largely determined by the structural and electrical properties of the water-membrane interface. We investigate these properties by the molecular dynamics method. Over the time scales of the simulations, the membrane undergoes fluctuations described by the capillary wave model. These fluctuations produce occasional thinning defects in the membrane which provide effective pathways for passive transport of ions and small molecules across the membrane. Ions moving through the membrane markedly disrupt its structure and allow for significant water penetration into the membrane interior. Selectivity of transport, with respect to ionic charge, is determined by the interfacial electrostatic potential. Many small molecules. of potential significance in catalysis, bioenergetics and pharmacology, are shown to bind to the interface. The energetics and dynamics of this process will be discussed.

  5. Mössbauer study 57Fe in ultrathin trilayer films with sharp and rough interfaces

    NASA Astrophysics Data System (ADS)

    Pogorily, A. N.; Bondarkova, G. V.; Razumov, O. N.; Shypil, E. V.

    2011-04-01

    Trilayer thin films Py/57Fe/Gd and Gd/57Fe/Py (Py: Fe20Ni80 permalloy) have been prepared by electron-beam evaporation and investigated using conversion-electron Mössbauer spectroscopy (CEMS), scanning tunneling microscopy (STM), polar magneto-optical Kerr effect (PMOKE), and ferromagnetic resonance (FMR). It was shown that the films deposited in the same vacuum and temperature runs but with the reverse order of the layers gave a different quality of interfaces: sharp (Py/57Fe/Gd) and rough (Gd/57Fe/Py). Different distribution of atoms in sharp and rough interfaces results in different magnetic properties: the Mössbauer spectra, FMR, and PMOKE data show the appearance of perpendicular magnetic anisotropy (PMA) and enhancement of magnetization in the samples with the rough Gd/Py interface.

  6. Hetero-epitaxial EuO interfaces studied by analytic electron microscopy

    SciTech Connect

    Mundy, Julia A.; Hodash, Daniel; Melville, Alexander; Held, Rainer; Mairoser, Thomas; Schmehl, Andreas; Muller, David A.; Kourkoutis, Lena F.; Schlom, Darrell G.

    2014-03-03

    With nearly complete spin polarization, the ferromagnetic semiconductor europium monoxide could enable next-generation spintronic devices by providing efficient ohmic spin injection into silicon. Spin injection is greatly affected by the quality of the interface between the injector and silicon. Here, we use atomic-resolution scanning transmission electron microscopy in conjunction with electron energy loss spectroscopy to directly image and chemically characterize a series of EuO|Si and EuO|YAlO{sub 3} interfaces fabricated using different growth conditions. We identify the presence of europium silicides and regions of disorder at the EuO|Si interfaces, imperfections that could significantly reduce spin injection efficiencies via spin-flip scattering.

  7. The Interface between Gd and Monolayer MoS2: A First-Principles Study

    PubMed Central

    Zhang, Xuejing; Mi, Wenbo; Wang, Xiaocha; Cheng, Yingchun; Schwingenschlögl, Udo

    2014-01-01

    We analyze the electronic structure of interfaces between two-, four- and six-layer Gd(0001) and monolayer MoS2 by first-principles calculations. Strong chemical bonds shift the Fermi energy of MoS2 upwards into the conduction band. At the surface and interface the Gd f states shift to lower energy and new surface/interface Gd d states appear at the Fermi energy, which are strongly hybridized with the Mo 4d states and thus lead to a high spin-polarization (ferromagnetically ordered Mo magnetic moments of 0.15 μB). Gd therefore is an interesting candidate for spin injection into monolayer MoS2. PMID:25482498

  8. Computational study of ion distributions at the air/liquid methanol interface

    SciTech Connect

    Sun, Xiuquan; Wick, Collin D.; Dang, Liem X.

    2011-06-16

    Molecular dynamic simulations with polarizable potentials were performed to systematically investigate the distribution of NaCl, NaBr, NaI, and SrCl2 at the air/liquid methanol interface. The density profiles indicated that there is no substantial enhancement of anions at the interface for the NaX systems in contrast to what was observed at the air/aqueous interface. The surfactant-like shape of the larger more polarizable halide anions is compensated by the surfactant nature of methanol itself. As a result, methanol hydroxy groups strongly interacted with one side of polarizable anions, in which their induced dipole points, and methanol methyl groups were more likely to be found near the positive pole of anion induced dipoles. Furthermore, salts were found to disrupt the surface structure of methanol, reducing the observed enhancement of methyl groups at the outer edge of the air/liquid methanol interface. With the additional of salts to methanol, the computed surface potentials increased, which is in contrast to what is observed in corresponding aqueous systems, where the surface potential decreases with the addition of salts. Both of these trends have been indirectly observed with experiments. This was found to be due to the propensity of anions for the air/water interface that is not present at the air/liquid methanol interface. This work was supported by the US Department of Energy Basic Energy Sciences' Chemical Sciences, Geosciences & Biosciences Division. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

  9. Trace Element Speciation and Distribution Study at Shewanella oneidensis MR-1 Biofilm/Mineral/Water Interfaces

    NASA Astrophysics Data System (ADS)

    Gelabert, A.; Wang, Y.; Gescher, J.; Ha, J.; Cordova, C. D.; Singer, D. M.; Spormann, A. M.; Trainor, T. P.; Eng, P. J.; Brown, G. E.

    2006-12-01

    the interactions among biofilm, metal(loid)s, and mineral surfaces. The long-period X-ray Standing Wave- fluorescent yield (XSW-FY) method, performed on BL ID-13-C at the APS, was used to obtain quantitative in situ information on the partitioning of Zn(II), Pb(II), and As(V) at these interfaces as a function of pH and ion concentration. XSW-FY results show that S. oneidensis biofilms do not block reactive sites on the hematite or alumina surfaces under our experimental conditions, which is consistent with the conclusion of our previous studies on trace element distributions at Burkholderia cepacia/mineral/water interfaces. Comparison of the observed trace element partitioning measured by XSW-FY with theoretical predictions of partitioning through thermodynamic models (using binding constants of metal(loid)s with the biofilm determined in this study and published binding constants of metal(loid)s with mineral substrates) allows us to describe biofilm local microenvironments and to understand how the biofilm coatings affect the reactivity of mineral surfaces.

  10. Thin-film CdTe detector for microdosimetric study of radiation dose enhancement at gold-tissue interface.

    PubMed

    Paudel, Nava Raj; Shvydka, Diana; Parsai, E Ishmael

    2016-09-01

    Presence of interfaces between high and low atomic number (Z) materials, often encountered in diagnostic imaging and radiation therapy, leads to radiation dose perturbation. It is characterized by a very narrow region of sharp dose enhancement at the interface. A rapid falloff of the dose enhancement over a very short distance from the interface makes the experimental dosimetry nontrivial. We use an in-house-built inexpensive thin-film Cadmium Telluride (CdTe) photodetector to study this effect at the gold-tissue interface and verify our experimental results with Monte Carlo (MC) modeling. Three-micron thick thin-film CdTe photodetectors were fabricated in our lab. One-, ten- or one hundred-micron thick gold foils placed in a tissue-equivalent-phantom were irradiated with a clinical Ir-192 high-dose-rate (HDR) source and current measured with a CdTe detector in each case was compared with the current measured for all uniform tissue-equivalent phantom. Percentage signal enhancement (PSE) due to each gold foil was then compared against MC modeled percentage dose enhancement (PDE), obtained from the geometry mimicking the experimental setup. The experimental PSEs due to 1, 10, and 100 μm thick gold foils at the closest measured distance of 12.5 μm from the interface were 42.6±10.8, 137.0±11.9, and 203.0±15.4, respectively. The corresponding MC modeled PDEs were 38.1±1., 164±1, and 249±1, respectively. The experimental and MC modeled values showed a closer agreement at the larger distances from the interface. The dose enhancement in the vicinity of gold-tissue interface was successfully measured using an in-house-built, high-resolution CdTe-based photodetector and validated with MC simulations. A close agreement between experimental and the MC modeled results shows that CdTe detector can be utilized for mapping interface dose distribution encountered in the application of ionizing radiation. PACS number(s): 29.40.Wk, 73.50.Pz, 87.53.Jw, 87.55.K.

  11. Thin-film CdTe detector for microdosimetric study of radiation dose enhancement at gold-tissue interface.

    PubMed

    Paudel, Nava Raj; Shvydka, Diana; Parsai, E Ishmael

    2016-09-08

    Presence of interfaces between high and low atomic number (Z) materials, often encountered in diagnostic imaging and radiation therapy, leads to radiation dose perturbation. It is characterized by a very narrow region of sharp dose enhancement at the interface. A rapid falloff of dose enhancement over a very short distance from the interface makes the experimental dosimetry nontrivial. We use an in-house-built inexpensive thin-film Cadmium Telluride (CdTe) photodetector to study this effect at the gold-tissue interface and verify our experimental results with Monte Carlo (MC) modeling. Three-micron thick thin-film CdTe photodetectors were fabricated in our lab. One-, ten- or one hundred-micron thick gold foils placed in a tissue-equivalent-phantom were irradiated with a clinical Ir-192 high-dose-rate (HDR) source and current measured with a CdTe detector in each case was compared with the current measured for all uniform tissue-equivalent phantom. Percentage signal enhancement (PSE) due to each gold foil was then compared against MC modeled percentage dose enhancement (PDE), obtained from the geometry mimicking the experimental setup. The experimental PSEs due to 1, 10, and 100 μm thick gold foils at the closest measured distance of 12.5μm from the interface were 42.6 ± 10.8 , 137.0 ± 11.9, and 203.0 ± 15.4, respectively. The corresponding MC modeled PDEs were 38.1 ± 1, 164 ± 1, and 249 ± 1, respectively. The experimental and MC modeled values showed a closer agreement at the larger distances from the interface. The dose enhancement in the vicinity of gold-tissue interface was successfully measured using an in-house-built, high-resolution CdTe-based photodetector and validated with MC simulations. A close agreement between experimental and the MC modeled results shows that CdTe detector can be utilized for mapping interface dose distribution encountered in the application of ionizing radiation.

  12. In situ studies of nucleation and assembly at soft-hard interfaces

    SciTech Connect

    Dutta, Pulak

    2013-04-01

    The overall goal of this project was the exploration of new ways to make organic and hybrid (organic-inorganic) materials for energy-related applications. Towards this end, our research focused on the structure and behavior of molecular monolayers at interfaces (including floating monolayers, transferred Langmuir-Blodgett monolayers, and self-assembled monolayers), as well as the biomimetic nucleation of inorganic crystals at soft-hard interfaces. The project resulted in a number of 'firsts' and other notable achievements, which are described in the report.

  13. Study of orbiter/payload interface communications configuration control board directive from an operational perspective

    NASA Technical Reports Server (NTRS)

    Addis, A. W.; Tatosian, C. G.; Lidsey, J. F.

    1974-01-01

    Orbiter/payload data and communications interface was examined. It was found that the Configuration Control Board Directive (CCBD) greatly increases the capability of the orbiter to communicate with a wide variety of projected shuttle payloads. Rather than being derived from individual payload communication requirements, the CCBD appears to be based on an operational philosophy that requires the orbiter to duplicate or augment the ground network/payload communication links. It is suggested that the implementation of the CCBD be reviewed and compared with the Level 1 Program Requirements Document, differences reconciled, and interface characteristics defined.

  14. A comparative study of interface reconstruction methods for multi-material ALE simulations

    SciTech Connect

    Kucharik, Milan; Garimalla, Rao; Schofield, Samuel; Shashkov, Mikhail

    2009-01-01

    In this paper we compare the performance of different methods for reconstructing interfaces in multi-material compressible flow simulations. The methods compared are a material-order-dependent Volume-of-Fluid (VOF) method, a material-order-independent VOF method based on power diagram partitioning of cells and the Moment-of-Fluid method (MOF). We demonstrate that the MOF method provides the most accurate tracking of interfaces, followed by the VOF method with the right material ordering. The material-order-independent VOF method performs some-what worse than the above two while the solutions with VOF using the wrong material order are considerably worse.

  15. A study of adhesion at the E-glass/FR4 interface

    SciTech Connect

    Kent, M.S.; Baca, P.; McNarama, W.F.; Jones, G.; Fein, D.; Wright, W.; Domeier, L.; Wu, W.L.; Wong, A.

    1995-11-01

    The majority of printed circuit boards are copper clad laminates composed of fiberglass cloth impregnated with FR4 epoxy. An important factor affecting the reliability of these assemblies is the integrity of the epoxy/glass fiber interface. The goal of this work is to investigate mechanisms for the loss of adhesive strength between E-glass and FR4 epoxy upon humidity and temperature conditioning. In this paper the authors discuss the distribution of moisture between the interface region and the bulk epoxy examined by neutron reflection, and the relationship of this data to adhesive strength.

  16. A comparative study of interface reconstruction methods for multi-material ALE simulations

    SciTech Connect

    Kucharik, Milan Garimella, Rao V. Schofield, Samuel P. Shashkov, Mikhail J.

    2010-04-01

    In this paper we compare the performance of different methods for reconstructing interfaces in multi-material compressible flow simulations. The methods compared are a material-order-dependent Volume-of-Fluid (VOF) method, a material-order-independent VOF method based on power diagram partitioning of cells and the Moment-of-Fluid method (MOF). We demonstrate that the MOF method provides the most accurate tracking of interfaces, followed by the VOF method with the right material ordering. The material-order-independent VOF method performs somewhat worse than the above two while the solutions with VOF using the wrong material order are considerably worse.

  17. Technical writing versus technical writing

    NASA Technical Reports Server (NTRS)

    Dillingham, J. W.

    1981-01-01

    Two terms, two job categories, 'technical writer' and 'technical author' are discussed in terms of industrial and business requirements and standards. A distinction between 'technical writing' and technical 'writing' is made. The term 'technical editor' is also considered. Problems inherent in the design of programs to prepare and train students for these jobs are discussed. A closer alliance between industry and academia is suggested as a means of preparing students with competent technical communication skills (especially writing and editing skills) and good technical skills.

  18. Diffuse interface methods for inverse problems: case study for an elliptic Cauchy problem

    NASA Astrophysics Data System (ADS)

    Burger, Martin; Løseth Elvetun, Ole; Schlottbom, Matthias

    2015-12-01

    Many inverse problems have to deal with complex, evolving and often not exactly known geometries, e.g. as domains of forward problems modeled by partial differential equations. This makes it desirable to use methods which are robust with respect to perturbed or not well resolved domains, and which allow for efficient discretizations not resolving any fine detail of those geometries. For forward problems in partial differential equations methods based on diffuse interface representations have gained strong attention in the last years, but so far they have not been considered systematically for inverse problems. In this work we introduce a diffuse domain method as a tool for the solution of variational inverse problems. As a particular example we study ECG inversion in further detail. ECG inversion is a linear inverse source problem with boundary measurements governed by an anisotropic diffusion equation, which naturally cries for solutions under changing geometries, namely the beating heart. We formulate a regularization strategy using Tikhonov regularization and, using standard source conditions, we prove convergence rates. A special property of our approach is that not only operator perturbations are introduced by the diffuse domain method, but more important we have to deal with topologies which depend on a parameter \\varepsilon in the diffuse domain method, i.e. we have to deal with \\varepsilon -dependent forward operators and \\varepsilon -dependent norms. In particular the appropriate function spaces for the unknown and the data depend on \\varepsilon . This prevents the application of some standard convergence techniques for inverse problems, in particular interpreting the perturbations as data errors in the original problem does not yield suitable results. We consequently develop a novel approach based on saddle-point problems. The numerical solution of the problem is discussed as well and results for several computational experiments are reported. In

  19. Using case studies to teach an engineering technology technical writing class

    NASA Technical Reports Server (NTRS)

    Green, M. M.

    1981-01-01

    The use of the case method in teaching various technical communication skills is described. Features of the method considered include: solving communication problems, identifying an audience, planning written communications, presenting written communications, and using visual aids.

  20. Promotion of Linkage between Technical and Vocational Education and the World of Work. UNEVOC Studies in Technical and Vocational Education, Number 10.

    ERIC Educational Resources Information Center

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

    This document contains seven papers about and from an international meeting on promoting linkage between technical and vocational education and the world of work. The first paper, a Final Report on the "International Expert Meeting on the Promotion of Linkage between Technical/Vocational Education and the World of Work (Tokyo, Japan, 3-6…

  1. Study on technical improvements for SOP of LINGAO 3 and 4 under construction in China

    SciTech Connect

    Ji, S.; Pechuzal, F.; Yan, L.; Yin, Z.; Wang, Z.; Zhou, H.

    2006-07-01

    This paper focuses on the emergency operating procedures planed to be design to manage the incidental and accidental situation of the NPPs on the LINGAO 3 and 4 nuclear plants project under construction in the South of China. Regarding the operation principles of the NPPs, the CNPEC Project management has launched two major improvements on the LAO 3 and 4 NPPs that are: Implementation of a Digital Control System (DCS) combined with a fully computerized MMI and backed-up with a conventional control mean (Back-up Panel) implementation of the state oriented procedures (SOP) for the incidental and accidental situations of the plant. Firstly, the domains covered with the SOP operating rules as well as the current technical development needed for the computerized-based SOP operating instructions design are detailed in this paper. Thus the structure of the SOP computerized operating instructions, the design of synthesis information and automatic diagnosis, the SOP operation in case of unavailability of the computerized MMI, are studied in the elaboration processing of the SOP. The availability of the NSSS functions and of the supply functions, as well as the fire action operating concerns are involved in this design activity. Finally, in the scope of these studies, the human factors considerations are considered in order to reduce the likelihood of human errors, to gain maximum benefit of the implemented technology and to increase the performance. (authors)

  2. Making fired bricks with spent equilibrium catalyst-a technical feasibility study

    USGS Publications Warehouse

    Chou, M.-L.; Chen, L.-M.; Lai, Y.-C.; Chou, S.-F.

    2009-01-01

    Fluid catalytic cracking in an oil refinery uses a catalyst, such as an alumino-silicate zeolite, in the conversion of heavy hydrocarbons to light hydrocarbons. A small fraction of the catalyst is continually replaced with fresh catalyst to maintain activity. In North America, more than 400 tons of spent alumino-silicate equilibrium catalyst (spent e-cat), and worldwide, more than 1,100 tons, are generated daily, most of which is disposed of in landfills (municipal and on-site facilities). In this study, three spent e-cat samples were tested in a value-added application that would utilize this waste in the manufacturing of fired bricks. The results of this study indicate that spent e-cat is a technically feasible raw material substitute for the clay and shale commonly used in fired brick production. Fired bricks produced with up to 30 wt% of spent e-cat showed good physical appearance and their water absorption properties met the ASTM C 62 specifications for building bricks of either the moderate-or severe-weathering grade.

  3. Technical Note: A Monte Carlo study of magnetic-field-induced radiation dose effects in mice

    PubMed Central

    Liao, Zhongxing; Melancon, Adam D.; Guindani, Michele; Followill, David S.; Tailor, Ramesh C.; Hazle, John D.; Court, Laurence E.

    2015-01-01

    Purpose: Magnetic fields are known to alter radiation dose deposition. Before patients receive treatment using an MRI-linear accelerator (MRI-Linac), preclinical studies are needed to understand the biological consequences of magnetic-field-induced dose effects. In the present study, the authors sought to identify a beam energy and magnetic field strength combination suitable for preclinical murine experiments. Methods: Magnetic field dose effects were simulated in a mouse lung phantom using various beam energies (225 kVp, 350 kVp, 662 keV [Cs-137], 2 MV, and 1.25 MeV [Co-60]) and magnetic field strengths (0.75, 1.5, and 3 T). The resulting dose distributions were compared with those in a simulated human lung phantom irradiated with a 6 or 8 MV beam and orthogonal 1.5 T magnetic field. Results: In the human lung phantom, the authors observed a dose increase of 45% and 54% at the soft-tissue-to-lung interface and a dose decrease of 41% and 48% at the lung-to-soft-tissue interface for the 6 and 8 MV beams, respectively. In the mouse simulations, the magnetic fields had no measurable effect on the 225 or 350 kVp dose distribution. The dose increases with the Cs-137 beam for the 0.75, 1.5, and 3 T magnetic fields were 9%, 29%, and 42%, respectively. The dose decreases were 9%, 21%, and 37%. For the 2 MV beam, the dose increases were 16%, 33%, and 31% and the dose decreases were 9%, 19%, and 30%. For the Co-60 beam, the dose increases were 19%, 54%, and 44%, and the dose decreases were 19%, 42%, and 40%. Conclusions: The magnetic field dose effects in the mouse phantom using a Cs-137, 3 T combination or a Co-60, 1.5 or 3 T combination most closely resemble those in simulated human treatments with a 6 MV, 1.5 T MRI-Linac. The effects with a Co-60, 1.5 T combination most closely resemble those in simulated human treatments with an 8 MV, 1.5 T MRI-Linac. PMID:26328998

  4. Technical Note: A Monte Carlo study of magnetic-field-induced radiation dose effects in mice

    SciTech Connect

    Rubinstein, Ashley E.; Liao, Zhongxing; Melancon, Adam D.; Followill, David S.; Tailor, Ramesh C.; Guindani, Michele; Hazle, John D.; Court, Laurence E.

    2015-09-15

    Purpose: Magnetic fields are known to alter radiation dose deposition. Before patients receive treatment using an MRI-linear accelerator (MRI-Linac), preclinical studies are needed to understand the biological consequences of magnetic-field-induced dose effects. In the present study, the authors sought to identify a beam energy and magnetic field strength combination suitable for preclinical murine experiments. Methods: Magnetic field dose effects were simulated in a mouse lung phantom using various beam energies (225 kVp, 350 kVp, 662 keV [Cs-137], 2 MV, and 1.25 MeV [Co-60]) and magnetic field strengths (0.75, 1.5, and 3 T). The resulting dose distributions were compared with those in a simulated human lung phantom irradiated with a 6 or 8 MV beam and orthogonal 1.5 T magnetic field. Results: In the human lung phantom, the authors observed a dose increase of 45% and 54% at the soft-tissue-to-lung interface and a dose decrease of 41% and 48% at the lung-to-soft-tissue interface for the 6 and 8 MV beams, respectively. In the mouse simulations, the magnetic fields had no measurable effect on the 225 or 350 kVp dose distribution. The dose increases with the Cs-137 beam for the 0.75, 1.5, and 3 T magnetic fields were 9%, 29%, and 42%, respectively. The dose decreases were 9%, 21%, and 37%. For the 2 MV beam, the dose increases were 16%, 33%, and 31% and the dose decreases were 9%, 19%, and 30%. For the Co-60 beam, the dose increases were 19%, 54%, and 44%, and the dose decreases were 19%, 42%, and 40%. Conclusions: The magnetic field dose effects in the mouse phantom using a Cs-137, 3 T combination or a Co-60, 1.5 or 3 T combination most closely resemble those in simulated human treatments with a 6 MV, 1.5 T MRI-Linac. The effects with a Co-60, 1.5 T combination most closely resemble those in simulated human treatments with an 8 MV, 1.5 T MRI-Linac.

  5. Quality management case studies in health service emergencies: SARS and wildland-urban interface fires.

    PubMed

    Lynch, Tim; Dauphinee, Wayne

    2005-01-01

    The province of British Columbia, Canada, experienced 2 major health emergency situations during 2003: severe acute respiratory syndrome (SARS) in early 2003 and wildland-urban interface fires during the summer of 2003. The interface fires occurred within the boundaries of the Interior Health Authority, 1 of 5 health authorities responsible for the delivery of health services in their respective areas of the province. The British Columbia Center for Disease Control (BCCDC) managed the SARS crisis in the province. Both organizations subsequently conducted quality management reviews of their handling of these emergency situations. This article reports on the quality management review of health services delivery during the interface fires and explores the role of physicians during regional emergencies. A similar report was published in the Spring 2004 edition of Quality Management in Health Care on the way SARS was managed at the BCCDC. This article also compares managing a foreseeable emergency situation, such as a wildland-urban interface fire, with managing the unknown, which describes the situation during the initial stages of SARS. The realities confronting the unknown, and the need to manage the situation such that learning and discovery environments are allowed to come into being and evolve rapidly, are discussed.

  6. A study of adhesion at the E-glass/FR4 interface

    SciTech Connect

    Kent, M.S.; Baca, P.; McNamara, W.F.

    1995-12-31

    The goal of this work is to investigate mechanisms for the loss of adhesive strength between E-glass and FR4 epoxy upon-humidity and temperature conditioning. In this paper we discuss the distribution of moisture between the interface region and the bulk epoxy examined by neutron reflection, and the relationship of this data to adhesive strength.

  7. A Chemical and Structural Study of the A1N-Si Interface

    NASA Technical Reports Server (NTRS)

    George, T.; Beye, R.

    1997-01-01

    Samples of A1N grown on silicon [111] subtrates were examined using electron enery loss spectroscopy (EELS) and selected area diffraction (SAD) with high-resolution transmission electron microscopy (TEM) to determine the source of out-of-place tilts and in-plane rotations of the A1N crystallites at the Si interface.

  8. Local/Global Cognitive Interfaces within Industrial Districts: An Italian Case Study

    ERIC Educational Resources Information Center

    Grandinetti, Roberto

    2011-01-01

    Purpose: With the advance of globalization the competitive chances of industrial districts depends increasingly on their ability to connect to the cognitive circuits of the global economy. This challenge demands the presence of local actors capable of acting as cognitive interfaces between the district context and the global environment. The paper…

  9. Using Multiple Dialog Modes in a User-System Interface to Accomodate Different Levels of User Experience: An Experimental Study.

    DTIC Science & Technology

    1986-01-01

    an expert has gained through studying and experience. Hayes’ [861 study of great painters and composers who are considered to be experts in their...Underlying Concepts: A great deal of flexibility exists in this component or dimension of a user-system interface but these concepts apply to all dialog...Total maximum points available for a raw performance score was 92. A subject’s raw score was then devided by the number of actions (23) to get the average

  10. Study of wetting on chemically soften interfaces by using combined solution thermodynamics and DFT calculations: forecasting effective softening elements.

    PubMed

    Shu, Guo Gang; Xu, Qiang; Wu, Ping

    2015-04-15

    Despite recent progress in understanding the wetting principles on soft solids, the roles of chemical bonding in the formation of interfaces have been largely ignored, because most of these studies are conducted at room temperatures. Here we propose a universal wetting principle from solution thermodynamics to account for the softening of both the solid and liquid surfaces (stable or metastable). Density functional theory (DFT) calculations are applied to evaluate the stability and electron transportation across the interfaces. We find that wetting is dominated by the system entropy changes involving not only the stable liquid alloy phase but also the metastable liquid oxide phases. The state-of-art multicomponent solution thermodynamic models and databases are applied to describe the entropy changes and predict the wetting behaviors. Our results show that by chemically softening either the liquid or the solid phase, the wetting angle reduces. And an effective soften agent/additive (either in the form of chemical elements or molecules) will weaken the bonds within the liquid (or solid) phase and promote new bonds at the interfaces, thus increasing the interface entropy. Subsequently, as an example, Ti and Zr are proposed as effective softening elements to improve the wetting of aluminum liquid on B6Si(s). This approach provides a concept and tool to advance research in catalytic chemistry, nucleation (growth), elastowetting, and cell-substrate interactions.

  11. Molecular dynamics study of the processes in the vicinity of the n-dodecane vapour/liquid interface

    NASA Astrophysics Data System (ADS)

    Xie, Jian-Fei; Sazhin, Sergei S.; Cao, Bing-Yang

    2011-11-01

    Molecular dynamics (MD) simulation is used to study the evaporation and condensation of n-dodecane (C12H26), the closest approximation to Diesel fuel. The interactions in chain-like molecular structures are modelled using an optimised potential for liquid simulation (OPLS). The thickness of the transition layer between the liquid and vapour phases at equilibrium is estimated. It is shown that molecules at the liquid surface need to obtain relatively large translational energy to evaporate. The vapour molecules with large translational energy can easily penetrate deeply into the transition layer and condense in the liquid phase. The evaporation/condensation coefficient is estimated and the results are shown to be compatible with the previous estimates based on the MD analysis and the estimate based on the transition state theory. The velocity distribution functions of molecules at the liquid-vapour equilibrium state are found in the liquid phase, interface, and the vapour phase. These functions in the liquid phase and at the interface are shown to be close to isotropic Maxwellian for all velocity components. The velocity distribution function in the vapour phase is shown to be close to bi-Maxwellian with the temperature for the distribution normal to the interface being larger than the one for the distribution parallel to the interface.

  12. The application of the symmetry properties of optical second harmonic generation to studies of interfaces and gases

    SciTech Connect

    Feller, M.B.

    1991-11-01

    Optical second harmonic generation has proven to be a powerful tool for studying interfaces. The symmetry properties of the process allow for surface sensitivity not available with other optical methods. In this thesis, we take advantage of these symmetry properties SHG to study a variety of interesting systems not previously studied with this technique. We show that optical second harmonic generation is an effective surface probe with a submonolayer sensitivity for media without inversion symmetry. We demonstrate the technique at a gallium arsenide surface, exploiting the different symmetry properties of the bulk and surface of the crystal to isolate the surface contribution. We also demonstrate that optical second harmonic generation can be used to determine the anisotropic orientational distribution of a surface monolayer of molecules. We apply the technique to study homogeneously aligned liquid crystal cells. To further explore the LC-polymer interface, we used SHG to study the surface memory effect. The surface memory effect is the rendering of an isotropic interface anisotropic by putting it in contact with an anisotropic bulk. Last, we describe some preliminary measurements of a time-resolved spectroscopic study of the phenomenon of second harmonic generation in a gas. The construction of a 500 microjoule pulsed, tunable laser source is described.

  13. [Experience of the development special medical technical laboratory for studies of effects caused by potent electromagnetic radiation in biologic objects].

    PubMed

    Gorodetsky, B N; Kalyada, T V; Petrov, S V

    2015-01-01

    This article covers topics of creating special medical technical laboratory for medial and biologic studies concerning influence of potent high-frequency elecromagnetic radiation on various biologic objects. The authors gave example of such laboratory, described its construction features, purpose and main characteristics of the included devices.

  14. Common Core State Standards for English Language Arts & Literacy in History/Social Studies, Science, and Technical Subjects

    ERIC Educational Resources Information Center

    Common Core State Standards Initiative, 2010

    2010-01-01

    The Common Core State Standards for English Language Arts & Literacy in History/Social Studies, Science, and Technical Subjects ("the Standards") are the culmination of an extended, broad-based effort to fulfill the charge issued by the states to create the next generation of K-12 standards in order to help ensure that all students…

  15. Communication and Collaboration in Library Technical Services: A Case Study of New York University in Abu Dhabi

    ERIC Educational Resources Information Center

    Parrott, Justin

    2016-01-01

    New York University Abu Dhabi Library has developed new strategies to increase efficiency in technical services processing between units based in New York and Abu Dhabi. This case study discusses the challenges specific to the international context and the methods used to overcome them, increase speed processing, and ultimately improve patron…

  16. Monitoring the Effect of Internet Use on Students Behavior Case Study: Technical Faculty Bor, University of Belgrade

    ERIC Educational Resources Information Center

    Niculovic, Milica; Zivkovic, Dragana; Manasijevic, Dragan; Strbac, Nada

    2012-01-01

    A large number of criteria for evaluating Internet addiction have been developed recently. The research of Internet addiction among students of the Technical faculty in Bor, University of Belgrade has been conducted and its results are presented in this paper. The study included 270 students using criteria of Young's Internet Addiction Test. In…

  17. Field Study: A Welding Survey of the Blackhawk Technical Institute Industries (Up-dating the Welding Curriculum).

    ERIC Educational Resources Information Center

    Lesch, Gerald E.

    In 1972, the welding department personnel at Blackhawk Technical Institute in Wisconsin undertook the project of updating the curriculum of their one-year welding degree program. A study was conducted of local welding industries to determine hiring policies, the tools and equipment a beginning welder should purchase, the types of welding processes…

  18. Interprofessional non-technical skills for surgeons in disaster response: a qualitative study of the Australian perspective.

    PubMed

    Willems, Anneliese; Waxman, Buce; Bacon, Andrew K; Smith, Julian; Peller, Jennifer; Kitto, Simon

    2013-03-01

    Interprofessional non-technical skills for surgeons in disaster response have not yet been developed. The aims of this study were to identify the non-technical skills required of surgeons in disaster response and training for disaster response and to explore the barriers and facilitators to interprofessional practice in surgical teams responding to disasters. Twenty health professionals, with prior experience in natural disaster response or education, participated in semi-structured in-depth interviews. A qualitative matrix analysis design was used to thematically analyze the data. Non-technical skills for surgeons in disaster response identified in this study included skills for austere environments, cognitive strategies and interprofessional skills. Skills for austere environments were physical self-care including survival skills, psychological self-care, flexibility, adaptability, innovation and improvisation. Cognitive strategies identified in this study were "big picture" thinking, situational awareness, critical thinking, problem solving and creativity. Interprofessional attributes include communication, team-player, sense of humor, cultural competency and conflict resolution skills. "Interprofessionalism" in disaster teams also emerged as a key factor in this study and incorporated elements of effective teamwork, clear leadership, role adjustment and conflict resolution. The majority of participants held the belief that surgeons needed training in non-technical skills in order to achieve best practice in disaster response. Surgeons considerring becoming involved in disaster management should be trained in these skills, and these skills should be incorporated into disaster preparation courses with an interprofessional focus.

  19. C2 Link Security for UAS: Technical Literature Study and Preliminary Functional Requirements. Version 0.9 (Working Draft)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This document provides a study of the technical literature related to Command and Control (C2) link security for Unmanned Aircraft Systems (UAS) for operation in the National Airspace System (NAS). Included is a preliminary set of functional requirements for C2 link security.

  20. The De-Facto Privatization of Secondary Education in Egypt: A Study of Private Tutoring in Technical and General Schools

    ERIC Educational Resources Information Center

    Sobhy, Hania

    2012-01-01

    Most secondary school students in Egypt enrol in private tutoring in almost all subjects throughout the school year. A large proportion of students have stopped attending school altogether due to their reliance on tutoring. This study of how educational markets are perpetuated at school level finds that in the technical track catering to the…