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Sample records for materials sbir phase

  1. An Overview of 2014 SBIR Phase I and Phase II Materials Structures for Extreme Environments

    Science.gov (United States)

    Nguyen, Hung D.; Steele, Gynelle C.; Morris, Jessica R.

    2015-01-01

    NASA's Small Business Innovation Research (SBIR) program focuses on technological innovation by investing in development of innovative concepts and technologies to help NASA mission directorates address critical research needs for Agency programs. This report highlights nine of the innovative SBIR 2014 Phase I and Phase II projects that emphasize one of NASA Glenn Research Center's six core competencies-Materials and Structures for Extreme Environments. The technologies cover a wide spectrum of applications such as high temperature environmental barrier coating systems, deployable space structures, solid oxide fuel cells, and self-lubricating hard coatings for extreme temperatures. Each featured technology describes an innovation, technical objective, and highlights NASA commercial and industrial applications. This report provides an opportunity for NASA engineers, researchers, and program managers to learn how NASA SBIR technologies could help their programs and projects, and lead to collaborations and partnerships between the small SBIR companies and NASA that would benefit both.

  2. An Overview of SBIR Phase 2 Materials Structures for Extreme Environments

    Science.gov (United States)

    Nguyen, Hung D.; Steele, Gynelle C.

    2015-01-01

    Technological innovation is the overall focus of NASA's Small Business Innovation Research (SBIR) program. The program invests in the development of innovative concepts and technologies to help NASA's mission directorates address critical research and development needs for agency projects. This report highlights innovative SBIR Phase II projects from 2007-2012 specifically addressing Areas in Materials and Structures for Extreme Environments which is one of six core competencies at NASA Glenn Research Center. There are twenty three technologies featured with emphasis on a wide spectrum of applications such as fine-filament superconductor wire, composite oxide cathode materials, nano-composites, high radiation solar cell, wrapped multilayer insulation, thin aerogel, and much more. Each article in this booklet describes an innovation, technical objective, and highlights NASA commercial and industrial applications. This report serves as an opportunity for NASA personnel including engineers, researchers, and program managers to learn of NASA SBIR's capabilities that might be crosscutting into this technology area. As the result, it would cause collaborations and partnerships between the small companies and NASA Programs and Projects resulting in benefit to both SBIR companies and NASA.

  3. An Overview of Materials Structures for Extreme Environments Efforts for 2015 SBIR Phases I and II

    Science.gov (United States)

    Nguyen, Hung D.; Steele, Gynelle C.

    2017-01-01

    Technological innovation is the overall focus of NASA's Small Business Innovation Research (SBIR) program. The program invests in the development of innovative concepts and technologies to help NASA's mission directorates address critical research and development needs for Agency projects. This report highlights innovative SBIR 2015 Phase I and II projects that specifically address areas in Materials and Structures for Extreme Environments, one of six core competencies at NASA Glenn Research Center. Each article describes an innovation, defines its technical objective, and highlights NASA applications as well as commercial and industrial applications. Ten technologies are featured: metamaterials-inspired aerospace structures, metallic joining to advanced ceramic composites, multifunctional polyolefin matrix composite structures, integrated reacting fluid dynamics and predictive materials degradation models for propulsion system conditions, lightweight inflatable structural airlock (LISA), copolymer materials for fused deposition modeling 3-D printing of nonstandard plastics, Type II strained layer superlattice materials development for space-based focal plane array applications, hydrogenous polymer-regolith composites for radiation-shielding materials, a ceramic matrix composite environmental barrier coating durability model, and advanced composite truss printing for large solar array structures. This report serves as an opportunity for NASA engineers, researchers, program managers, and other personnel to learn about innovations in this technology area as well as possibilities for collaboration with innovative small businesses that could benefit NASA programs and projects.

  4. NASA SBIR abstracts of 1990 phase 1 projects

    Science.gov (United States)

    Schwenk, F. C.; Gilman, J. A.; Paige, J. B.

    1991-01-01

    The research objectives of the 280 projects placed under contract in the National Aeronautics and Space Administration (NASA) 1990 Small Business Innovation Research (SBIR) Phase 1 program are described. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses in response to NASA's 1990 SBIR Phase 1 Program Solicitation. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 280, in order of its appearance in the body of the report. The document also includes Appendixes to provide additional information about the SBIR program and permit cross-reference in the 1990 Phase 1 projects by company name, location by state, principal investigator, NASA field center responsible for management of each project, and NASA contract number.

  5. NASA SBIR abstracts of 1992, phase 1 projects

    Science.gov (United States)

    Schwenk, F. C.; Gilman, J. A.; Paige, J. B.; Sacknoff, S. M.

    1993-01-01

    The objectives of 346 projects placed under contract by the Small Business Innovation Research (SBIR) program of the National Aeronautics and Space Administration (NASA) are described. These projects were selected competitively from among proposals submitted to NASA in response to the 1992 SBIR Program Solicitation. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 346, in order of its appearance in the body of the report. Appendixes to provide additional information about the SBIR program and permit cross-reference of the 1992 Phase 1 projects by company name, location by state, principal investigator, NASA Field Center responsible for management of each project, and NASA contract number are included.

  6. NASA SBIR abstracts of 1991 phase 1 projects

    Science.gov (United States)

    Schwenk, F. Carl; Gilman, J. A.; Paige, J. B.

    1992-01-01

    The objectives of 301 projects placed under contract by the Small Business Innovation Research (SBIR) program of the National Aeronautics and Space Administration (NASA) are described. These projects were selected competitively from among proposals submitted to NASA in response to the 1991 SBIR Program Solicitation. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 301, in order of its appearance in the body of the report. Appendixes to provide additional information about the SBIR program and permit cross-reference of the 1991 Phase 1 projects by company name, location by state, principal investigator, NASA Field Center responsible for management of each project, and NASA contract number are included.

  7. Combinatorial Approach for the Discovery of New Scintillating Materials SBIR Phase I Final Report Report # DOE/ER/84310

    Energy Technology Data Exchange (ETDEWEB)

    Cronin, J P; Agrawal, A; Tonazzi, J C

    2006-08-22

    The combinatorial approach for the discovery of new scintillating materials has been investigated using the wet-chemical (sol-gel) synthesis methods. Known scintillating compounds Lu2SiO5 (LSO) and (LuAl)O3 (LAO) and solid solutions in the systems of Lu2O3 -Y2O3 – SiO2 (CeO2-doped) (LYSO) and Lu2O3 -Y2O3 – Al2O3 (CeO2 –doped) (LYAO) were synthesized from sol-gel precursors. Sol-gel precursors were formulated from alkoxides and nitrates and acetates of the cations. Sol-gel solution precursors were formulated for the printing of microdot arrays of different compositions in the above oxide systems. Microdot arrays were successfully printed on C-cut and R-cut sapphire substrates using Biodot printer at Los Alamos National Laboratory (LANL). The microdot arrays were adherent and stable after heat-treating at 1665oC and had an average thickness of around 2m. X-ray fluorescence elemental mapping showed the arrays to be of the correct chemical composition. Sintered microdots were found to be highly crystalline by microscopic observation and X-ray diffraction. Scintillation was not clearly detectable by visual observation under UV illumination and by video observation under the scanning electron beam of an SEM. The microdots were either poorly scintillating or not scintillating under the present synthesis and testing conditions. Further improvements in the synthesis and processing of the microdot arrays as well as extensive scintillation testing are needed.

  8. An Overview of SBIR Phase 2 Communications Technology and Development

    Science.gov (United States)

    Nguyen, Hung D.; Steele, Gynelle C.

    2015-01-01

    Technological innovation is the overall focus of NASA's Small Business Innovation Research (SBIR) program. The program invests in the development of innovative concepts and technologies to help NASA's mission directorates address critical research and development needs for agency projects. This report highlights innovative SBIR Phase II projects from 2007-2012 specifically addressing areas in Communications Technology and Development which is one of six core competencies at NASA Glenn Research Center. There are eighteen technologies featured with emphasis on a wide spectrum of applications such as with a security-enhanced autonomous network management, secure communications using on-demand single photons, cognitive software-defined radio, spacesuit audio systems, multiband photonic phased-array antenna, and much more. Each article in this booklet describes an innovation, technical objective, and highlights NASA commercial and industrial applications. This report serves as an opportunity for NASA personnel including engineers, researchers, and program managers to learn of NASA SBIR's capabilities that might be crosscutting into this technology area. As the result, it would cause collaborations and partnerships between the small companies and NASA Programs and Projects resulting in benefit to both SBIR companies and NASA.

  9. 78 FR 30951 - SBIR/STTR Phase I to Phase II Transition Benchmarks

    Science.gov (United States)

    2013-05-23

    ... ADMINISTRATION SBIR/STTR Phase I to Phase II Transition Benchmarks AGENCY: U.S. Small Business Administration...; Amended. SUMMARY: The Small Business Administration (SBA) is soliciting comments on proposed amendments to... Director, Office of Innovation, Small Business Administration, 409 Third Street SW., Washington, DC...

  10. An Overview of 2014 SBIR Phase 1 and Phase 2 Communications Technology and Development

    Science.gov (United States)

    Nguyen, Hung D.; Steele, Gynelle C.; Morris, Jessica R.

    2015-01-01

    NASA's Small Business Innovation Research (SBIR) program focuses on technological innovation by investing in development of innovative concepts and technologies to help NASA mission directorates address critical research needs for Agency programs. This report highlights eight of the innovative SBIR 2014 Phase I and Phase II projects that emphasize one of NASA Glenn Research Center's six core competencies-Communication Technology and Development. The technologies cover a wide spectrum of applications such as X-ray navigation, microsensor instrument for unmanned aerial vehicle airborne atmospheric measurements, 16-element graphene-based phased array antenna system, interferometric star tracker, ultralow power fast-response sensor, and integrated spacecraft navigation and communication. Each featured technology describes an innovation, technical objective, and highlights NASA commercial and industrial applications. This report provides an opportunity for NASA engineers, researchers, and program managers to learn how NASA SBIR technologies could help their programs and projects, and lead to collaborations and partnerships between the small SBIR companies and NASA that would benefit both.

  11. An Overview of 2014 SBIR Phase 1 and Phase 2 Air-Breathing Propulsion

    Science.gov (United States)

    Nguyen, Hung D.; Steele, Gynelle C.; Morris, Jessica R.

    2015-01-01

    NASA's Small Business Innovation Research (SBIR) program focuses on technological innovation by investing in development of innovative concepts and technologies to help NASA mission directorates address critical research needs for Agency programs. This report highlights nine of the innovative SBIR 2014 Phase I and Phase II projects that emphasize one of NASA Glenn Research Center's six core competencies-Air-Breathing Propulsion. The technologies cover a wide spectrum of applications such as development of X-ray computed tomography (CT) imaging method for the measurement of complex 3D ice shapes, phased array techniques for low signal-to-noise ratio wind tunnels, compact kinetic mechanisms for petroleum-derived and alternative aviation fuels, and hybrid electric propulsion systems for a multirotor aircraft. Each featured technology describes an innovation, technical objective, and highlights NASA commercial and industrial applications. This report provides as an opportunity for NASA engineers, researchers, and program managers to learn how NASA SBIR technologies could help their programs and projects, and lead to collaborations and partnerships between the small SBIR companies and NASA that would benefit both.

  12. An Overview of Power, Energy Storage, and Conversion Efforts for 2014 SBIR Phases I and II

    Science.gov (United States)

    Nguyen, Hung D.; Steele, Gynelle C.

    2016-01-01

    Technological innovation is the overall focus of NASA's Small Business Innovation Research (SBIR) program. The program invests in the development of innovative concepts and technologies to help NASA's mission directorates address critical research and development needs for agency projects. NASA's Small Business Innovation Research (SBIR) program focuses on technological innovation by investing in development of innovative concepts and technologies to help NASA mission directorates address critical research needs for Agency programs. This report highlights 15 of the innovative SBIR 2014 Phase I and II projects that focus on one of NASA Glenn Research Center's six core competencies-Power, Energy Storage and Conversion. The technologies cover a wide spectrum of applications such as high-radiation-tolerant ceramic voltage isolators, development of hermetic sealing glasses for solid oxide fuel cells, rechargeable lithium metal cells, high-efficiency direct methane solid oxide fuel cell systems, Li metal protection for high-energy space batteries, isolated bidirectional direct current converters for distributed battery energy applications, and high-efficiency rad-hard ultrathin Si photovoltaic cell technology for space. Each article describes an innovation and technical objective and highlights NASA commercial and industrial applications. This report provides an opportunity for NASA engineers, researchers, and program managers to learn how NASA SBIR technologies could help their programs and projects, and lead to collaborations and partnerships between the small SBIR companies and NASA that would benefit both.

  13. An Overview of SBIR Phase 2 In-Space Propulsion and Cryogenic Fluids Management

    Science.gov (United States)

    Nguyen, Hung D.; Steele, Gynelle C.

    2015-01-01

    Technological innovation is the overall focus of NASA's Small Business Innovation Research (SBIR) program. The program invests in the development of innovative concepts and technologies to help NASA's mission directorates address critical research and development needs for agency projects. This report highlights innovative SBIR Phase II projects from 2007-2012 specifically addressing Areas in In-Space Propulsion and Cryogenic Fluids Management which is one of six core competencies at NASA Glenn Research Center. There are nineteen technologies featured with emphasis on a wide spectrum of applications such as high-performance Hall thruster support system, thruster discharge power converter, high-performance combustion chamber, ion thruster design tool, green liquid monopropellant thruster, and much more. Each article in this booklet describes an innovation, technical objective, and highlights NASA commercial and industrial applications. This report serves as an opportunity for NASA personnel including engineers, researchers, and program managers to learn of NASA SBIR's capabilities that might be crosscutting into this technology area. As the result, it would cause collaborations and partnerships between the small companies and NASA Programs and Projects resulting in benefit to both SBIR companies and NASA.

  14. An Overview of Air-Breathing Propulsion Efforts for 2015 SBIR Phase I

    Science.gov (United States)

    Nguyen, Hung D.; Steele, Gynelle C.

    2016-01-01

    NASA's Small Business Innovation Research (SBIR) program focuses on technological innovation by investing in development of innovative concepts and technologies to help NASA mission directorates address critical research needs for Agency programs. This report highlights 24 of the innovative SBIR 2015 Phase I projects that emphasize one of NASA Glenn Research Center's six core competencies-Air-Breathing Propulsion. The technologies cover a wide spectrum of applications such as hybrid nanocomposites for efficient aerospace structures; plasma flow control for drag reduction; physics-based aeroanalysis methods for open rotor conceptual designs; vertical lift by series hybrid power; fast pressure-sensitive paint systems for production wind tunnel testing; rugged, compact, and inexpensive airborne fiber sensor interrogators based on monolithic tunable lasers; and high sensitivity semiconductor sensor skins for multi-axis surface pressure characterization. Each featured technology describes an innovation and technical objective and highlights NASA commercial and industrial applications. This report provides an opportunity for NASA engineers, researchers, and program managers to learn how NASA SBIR technologies could help their programs and projects, and lead to collaborations and partnerships between the small SBIR companies and NASA that would benefit both.

  15. An Overview of SBIR Phase 2 Physical Sciences and Biomedical Technologies in Space

    Science.gov (United States)

    Nguyen, Hung D.; Steele, Gynelle C.

    2015-01-01

    Technological innovation is the overall focus of NASA's Small Business Innovation Research (SBIR) program. The program invests in the development of innovative concepts and technologies to help NASA's mission directorates address critical research and development needs for agency projects. This report highlights innovative SBIR Phase II projects from 2007-2012 specifically addressing areas in physical sciences and biomedical technologies in space, which is one of six core competencies at NASA Glenn Research Center. There are twenty two technologies featured with emphasis on a wide spectrum of applications such as reusable handheld electrolyte, sensor for bone markers, wideband single crystal transducer, mini treadmill for musculoskeletal, and much more. Each article in this report describes an innovation, technical objective, and highlights NASA commercial and industrial applications. This report serves as an opportunity for NASA personnel including engineers, researchers, and program managers to learn of NASA SBIR's capabilities that might be crosscutting into this technology area. As the result, it would cause collaborations and partnerships between the small companies and NASA Programs and Projects resulting in benefit to both SBIR companies and NASA.

  16. How to Improve SBIR Phase 3 Technology Commercialization Effectiveness: A NASA Glenn Internal Assessment

    Science.gov (United States)

    Horsham, Gary A. P.

    1999-01-01

    Governmental departments and agencies with responsibilities for implementing the Small Business Innovative Research program under the auspices of the Small Business Administration, are now required to be more accountable for phase 3 performance. At NASA Glenn Research Center, internal, one-on-one interviews were conducted with seven contracting officer technical representatives who have managed one or more SBIR contracts through completion of phase 2. A questionnaire consisting of nineteen questions was formulated and used for the above purpose. This self-assessment produced several comments, conclusions, and recommendations for consideration and potential application.

  17. Subsurface Monitor for Dissolved Inorganic Carbon at Geological Sequestration Site Phase 1 SBIR Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Sheng Wu

    2012-08-03

    Phase I research of this SBIR contract has yielded anticipated results and enable us to develop a practical new instrument to measure the Dissolved Inorganic Carbons (DIC) as well as Supercritical (SC) CO2 in underground brine water at higher sensitivity, lower cost, higher frequency and longer period of time for the Monitoring, Verification & Accounting (MVA) of CO2 sequestration as well as Enhanced Oil Recovery (EOR). We show that reduced cost and improved performance are possible; both future and emerging market exist for the proposed new instrument.

  18. Ultra-secure RF Tags for Safeguards and Security - SBIR Phase II Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Twogood, Richard E [Dirac Solutions Inc., Pleasanton, CA (United States)

    2015-01-27

    This is the Final Report for the DOE Phase II SBIR project “Ultra-secure RF Tags for Safeguards and Security.” The topics covered herein include technical progress made, progress against the planned milestones and deliverables, project outcomes (results, collaborations, intellectual property, etc.), and a discussion on future expectations of deployment and impacts of the results of this work. In brief, all planned work for the project was successfully completed, on or ahead of schedule and on budget. The major accomplishment was the successful development of a very advanced passive ultra-secure RFID tag system with combined security features unmatched by any commercially available ones. These tags have high-level dynamic encrypted authentication, a novel tamper-proofing mechanism, system software including graphical user interfaces and networking, and integration with a fiber-optic seal mechanism. This is all accomplished passively (with no battery) by incorporating sophisticated hardware in the tag which harvests the energy from the RFID readers that are interrogating the tag. Based on initial feedback (and deployments) at DOE’s Lawrence Livermore National Laboratory (LLNL), it is anticipated these tags and their offspring will meet DOE and international community needs for highly secure RFID systems. Beyond the accomplishment of those original objectives for the ultra-secure RF tags, major new spin-off thrusts from the original work were identified and successfully pursued with the cognizance of the DOE sponsor office. In particular, new classes of less sophisticated RFID tags were developed whose lineage derives from the core R&D thrusts of this SBIR. These RF “tag variants” have some, but not necessarily all, of the advanced characteristics described above and can therefore be less expensive and meet far wider markets. With customer pull from the DOE and its national laboratories, new RFID tags and systems (including custom readers and software) for

  19. 77 FR 23228 - Notice of Submission for OMB Review; Small Business Innovation Research (SBIR) Program-Phase II...

    Science.gov (United States)

    2012-04-18

    ... Public Law 106-554, the ``Small Business Reauthorization Act of 2000, H.R. 5667'' enacted on December 21... Notice of Submission for OMB Review; Small Business Innovation Research (SBIR) Program--Phase II--Grant Application Package SUMMARY: This application package invites small business concerns to submit a Phase...

  20. 77 FR 23229 - Submission for OMB Review; Small Business Innovation Research (SBIR) Program-Phase I-Grant...

    Science.gov (United States)

    2012-04-18

    ... Law 106- 554, the ``Small Business Reauthorization Act of ] 2000, H.R. 5667'' enacted on December 21... Submission for OMB Review; Small Business Innovation Research (SBIR) Program--Phase I--Grant Application Package SUMMARY: This application package invites small business concerns to submit a Phase I...

  1. 77 FR 63410 - SBIR/STTR Phase I to Phase II Transition Benchmarks

    Science.gov (United States)

    2012-10-16

    .... ACTION: Notice of Small Business Innovation Research and Small Business Technology Transfer Programs... publishing the Small Business Innovation Research (SBIR) and the Small Business Technology Transfer (STTR...; telephone (202) 205-6450; email ( Technology@sba.gov ). FOR FURTHER INFORMATION CONTACT: Edsel Brown,...

  2. An Overview of In-Space Propulsion and Cryogenics Fluids Management Efforts for 2014 SBIR Phases I and II

    Science.gov (United States)

    Nguyen, Hung D.; Steele, Gynelle C.

    2016-01-01

    NASA's Small Business Innovation Research (SBIR) program focuses on technological innovation by investing in the development of innovative concepts and technologies to help NASA's mission directorates address critical research and development needs for Agency programs. This report highlights 11 of the innovative SBIR 2014 Phase I and II projects from 2010 to 2012 that focus on one of NASA Glenn Research Center's six core competencies-In-Space Propulsion and Cryogenic Fluids Management. The technologies cover a wide spectrum of applications such as divergent field annular ion engines, miniature nontoxic nitrous oxide-propane propulsion, noncatalytic ignition systems for high-performance advanced monopropellant thrusters, nontoxic storable liquid propulsion, and superconducting electric boost pumps for nuclear thermal propulsion. Each article describes an innovation and technical objective and highlights NASA commercial and industrial applications. This report provides an opportunity for NASA engineers, researchers, and program managers to learn how NASA SBIR technologies could help their programs and projects, and lead to collaborations and partnerships between the small SBIR companies and NASA that would benefit both.

  3. Turnable Semiconductor Laser Spectroscopy in Hollow Optical Waveguides, Phase II SBIR

    Energy Technology Data Exchange (ETDEWEB)

    Gregory J. Fetzer, Ph.D.

    2001-12-24

    In this study a novel optical trace gas sensor based on a perforated hollow waveguide (PHW) was proposed. The sensor has been given the acronym ESHOW for Environmental Sensor using Hollow Optical Waveguides. Realizations of the sensor have demonstrated rapid response time (<2s), low minimum detection limits (typically around 3 x 10-5 absorbance). Operation of the PHW technology has been demonstrated in the near-infrared (NIR) and mid0infrared (MIR) regions of the spectrum. Simulation of sensor performance provided in depth understanding of the signals and signal processing required to provide high sensitivity yet retain rapid response to gas changes. A dedicated sensor electronics and software foundation were developed during the course of the Phase II effort. Commercial applications of the sensor are ambient air and continuous emissions monitoring, industrial process control and hazardous waste site monitoring. There are numerous other applications for such a sensor including medical diagnosis and treatment, breath analysis for legal purposes, water quality assessment, combustion diagnostics, and chemical process control. The successful completion of Phase II resulted in additional funding of instrument development by the Nations Institute of Heath through a Phase I SBIR grant and a strategic teaming relationship with a commercial manufacture of medical instrumentation. The purpose of the NIH grant and teaming relationship is to further develop the sensor to monitor NO in exhaled breath for the purposes of asthma diagnosis.

  4. NASA SBIR product catalog, 1990

    Science.gov (United States)

    Schwenk, F. Carl; Gilman, J. A.

    1990-01-01

    Since 1983 the NASA Small Business Innovation Research (SBIR) program has benefitted both the agency and the high technology small business community. By making it possible for more small businesses to participate in NASA's research and development, SBIR also provides opportunities for these entrepreneurs to develop products which may also have significant commercial markets. Structured in three phases, the SBIR program uses Phase 1 to assess the technical feasibility of novel ideas proposed by small companies and Phase 2 to conduct research and development on the best concepts. Phase 3, not funded by SBIR, is the utilization and/or commercialization phase. A partial list of products of NASA SBIR projects which have advanced to some degree into Phase 3 are provided with a brief description.

  5. DOE SBIR Phase II Final Report: Distributed Relevance Ranking in Heterogeneous Document Collections

    Energy Technology Data Exchange (ETDEWEB)

    Abe Lederman

    2007-01-08

    This report contains the comprehensive summary of the work performed on the SBIR Phase II project (“Distributed Relevance Ranking in Heterogeneous Document Collections”) at Deep Web Technologies (http://www.deepwebtech.com). We have successfully completed all of the tasks defined in our SBIR Proposal work plan (See Table 1 - Phase II Tasks Status). The project was completed on schedule and we have successfully deployed an initial production release of the software architecture at DOE-OSTI for the Science.gov Alliance's search portal (http://www.science.gov). We have implemented a set of grid services that supports the extraction, filtering, aggregation, and presentation of search results from numerous heterogeneous document collections. Illustration 3 depicts the services required to perform QuickRank™ filtering of content as defined in our architecture documentation. Functionality that has been implemented is indicated by the services highlighted in green. We have successfully tested our implementation in a multi-node grid deployment both within the Deep Web Technologies offices, and in a heterogeneous geographically distributed grid environment. We have performed a series of load tests in which we successfully simulated 100 concurrent users submitting search requests to the system. This testing was performed on deployments of one, two, and three node grids with services distributed in a number of different configurations. The preliminary results from these tests indicate that our architecture will scale well across multi-node grid deployments, but more work will be needed, beyond the scope of this project, to perform testing and experimentation to determine scalability and resiliency requirements. We are pleased to report that a production quality version (1.4) of the science.gov Alliance's search portal based on our grid architecture was released in June of 2006. This demonstration portal is currently available at http://science.gov/search30

  6. DOE Phase II SBIR: Spectrally-Assisted Vehicle Tracking - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Villeneuve, Pierre V. [Space Computer Corporation

    2013-02-28

    The goal of this Phase II SBIR has been to develop a prototype software package to demonstrate spectrally-aided vehicle tracking. The primary application is to show improved target vehicle tracking performance in complex environments where traditional spatial tracker systems may show reduced performance. Examples include scenarios where the target vehicle is obscured by a large structure for an extended period of time, or where the target is engaging in extreme maneuvers amongst other civilian vehicles. The target information derived from spatial processing is unable to differentiate between the green versus the red vehicle. Spectral signature exploitation enables comparison of new candidate targets with existing track signatures. The ambiguity in this confusing scenario is resolved by folding spectral analysis results into each target nomination and association processes. The work performed over the two-year effort was divided into three general areas: algorithm refinement, software prototype development, and prototype performance demonstration. The tasks performed under this Phase II resulted in the completion of a software tool suitable for evaluation and testing of advanced tracking concepts.

  7. An Overview of Communications Technology and Development Efforts for 2015 SBIR Phase I

    Science.gov (United States)

    Nguyen, Hung D.; Steele, Gynelle C.

    2017-01-01

    This report highlights innovative SBIR 2015 Phase I projects specifically addressing areas in Communications Technology and Development which is one of six core competencies at NASA Glenn Research Center. There are fifteen technologies featured with emphasis on a wide spectrum of applications such as novel solid state lasers for space-based water vapor dial; wide temperature, high voltage and energy density capacitors for aerospace exploration; instrument for airborne measurement of carbonyl sulfide; high-power tunable seed laser for methane Lidar transmitter; ROC-rib deployable ka-band antenna for nanosatellites; a SIC-based microcontroller for high-temperature in-situ instruments and systems; improved yield, performance and reliability of high-actuator-count deformable mirrors; embedded multifunctional optical sensor system; switching electronics for space-based telescopes with advanced AO systems; integrated miniature DBR laser module for Lidar instruments; and much more. Each article in this booklet describes an innovation, technical objective, and highlights NASA commercial and industrial applications. space-based water vapor dial; wide temperature, high voltage and energy density capacitors foraerospace exploration; instrument for airborne measurement of carbonyl sulfide; high-power tunable seed laser formethane Lidar transmitter; ROC-rib deployable ka-band antenna for nanosatellites.

  8. Parallel tools GUI framework-DOE SBIR phase I final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Galarowicz, James [Argo Navis Technologies LLC., Annapolis, MD (United States)

    2013-12-05

    Many parallel performance, profiling, and debugging tools require a graphical way of displaying the very large datasets typically gathered from high performance computing (HPC) applications. Most tool projects create their graphical user interfaces (GUI) from scratch, many times spending their project resources on simply redeveloping commonly used infrastructure. Our goal was to create a multiplatform GUI framework, based on Nokia/Digia’s popular Qt libraries, which will specifically address the needs of these parallel tools. The Parallel Tools GUI Framework (PTGF) uses a plugin architecture facilitating rapid GUI development and reduced development costs for new and existing tool projects by allowing the reuse of many common GUI elements, called “widgets.” Widgets created include, 2D data visualizations, a source code viewer with syntax highlighting, and integrated help and welcome screens. Application programming interface (API) design was focused on minimizing the time to getting a functional tool working. Having a standard, unified, and userfriendly interface which operates on multiple platforms will benefit HPC application developers by reducing training time and allowing users to move between tools rapidly during a single session. However, Argo Navis Technologies LLC will not be submitting a DOE SBIR Phase II proposal and commercialization plan for the PTGF project. Our preliminary estimates for gross income over the next several years was based upon initial customer interest and income generated by similar projects. Unfortunately, as we further assessed the market during Phase I, we grew to realize that there was not enough demand to warrant such a large investment. While we do find that the project is worth our continued investment of time and money, we do not think it worthy of the DOE's investment at this time. We are grateful that the DOE has afforded us the opportunity to make this assessment, and come to this conclusion.

  9. Inductive resistivity logging in steel-cased boreholes. SBIR Phase 2 progress report

    Energy Technology Data Exchange (ETDEWEB)

    Wilt, M.

    1999-07-01

    SBIR Phase 2 project 40145-97-I calls for the design and construction of a prototype inductive logging device to measure formation resistivity from within a steel-cased borehole. The SCIL (Steel Casing Induction Logger) tool is intended for reservoir characterization and process monitoring in an oil field environment. This report summarizes findings from the initial project period. In this phase, bench model measurements were made to test casing compensation schemes, numerical models were calculated to optimize the tool configuration and associated formation sensitivity and the preliminary design of the tool was completed. The bench tests constitute fundamental research on determining the characteristics of steel well casing and on developing means of separating the effects of the casing and the formation. This technology is crucial to the success of the project and significant progress has been made towards the goal of recovering the formation resistivity from inside the casing. Next, a series of sensitivity and tool configuration studies have been completed through partner Dr. David Alumbaugh at Sandia National Laboratories. These numerical results help to optimize the tool configuration and allow one to calculate the expected formation sensitivity. These models are preliminary to data interpretation software to be developed in the next project period. The initial hardware design of the tool has been completed, and ordering parts has begun for later manufacture and assembly. The tool, which is designed for maximum flexibility of deployment, will have a powerful transmitter, an array of three component sensors and sufficient dynamic range to operate in standard oil field steel-cased boreholes.

  10. Defense Small Business Innovation Research Program (SBIR) Volume 2. Navy Abstracts of Phase 1 Awards, 1987

    Science.gov (United States)

    1988-04-01

    DYNAMICS, INCLUDING AUTOPILOT , AND AN ADEQUATE SIMULATED TERRAIN IMAGE FOR VEHICLES WITH ON-BOARD SMALL BUSINESS INNOVATION RESEARCH (SBIR) PROGRAM...ELECTRONICS DOES NOT EXCEED A FRACTION OF A VOLT, NOT LIKELY IF THE RATE OF CHANGE OF AXIAL FLUX DENSITY IS LESS THAN 2.5 TESLA /SEC. A UNIQUE

  11. Defense Small Business Innovation Research Program (SBIR). Volume 4. Defense Agency Projects, Abstracts of Phase 1 Awards from FY 1989 SBIR Solicitation

    Science.gov (United States)

    1990-04-01

    LABORATORY UNDER THE CODE NAME " DELPHI ", FOR THE OFFICE OF STRATEGIC DEFENSE; AND BETATRON RESEARCH CONDUCTED BY BOTH U.S. AND SOVIET SOURCES SUPPORTS THE...TITLE: HYPERGOLIC FUEL INJECTOR FEATURES INCREASED UTILITY FOR REMOTELY PILOTED VEHICLES (RPVs) INCREASED RANGE ENDURANCE PAYLOAD MULTI.. TOPIC# 20...OFFICE: PM/SBIR IDENT#: 33860 A HYPERGOLIC FUEL INJECTOR IS DESCRIBED THAT ENABLES MULTIFUEL OPERATION, LOWER FUEL CONSUMPTION, AND ENHANCED ALL WEATHER

  12. Digital active material processing platform effort (DAMPER), SBIR phase 2

    Science.gov (United States)

    Blackburn, John; Smith, Dennis

    1992-01-01

    Applied Technology Associates, Inc., (ATA) has demonstrated that inertial actuation can be employed effectively in digital, active vibration isolation systems. Inertial actuation involves the use of momentum exchange to produce corrective forces which act directly on the payload being actively isolated. In a typical active vibration isolation system, accelerometers are used to measure the inertial motion of the payload. The signals from the accelerometers are then used to calculate the corrective forces required to counteract, or 'cancel out' the payload motion. Active vibration isolation is common technology, but the use of inertial actuation in such systems is novel, and is the focus of the DAMPER project. A May 1991 report was completed which documented the successful demonstration of inertial actuation, employed in the control of vibration in a single axis. In the 1 degree-of-freedom (1DOF) experiment a set of air bearing rails was used to suspend the payload, simulating a microgravity environment in a single horizontal axis. Digital Signal Processor (DSP) technology was used to calculate in real time, the control law between the accelerometer signals and the inertial actuators. The data obtained from this experiment verified that as much as 20 dB of rejection could be realized by this type of system. A discussion is included of recent tests performed in which vibrations were actively controlled in three axes simultaneously. In the three degree-of-freedom (3DOF) system, the air bearings were designed in such a way that the payload is free to rotate about the azimuth axis, as well as translate in the two horizontal directions. The actuator developed for the DAMPER project has applications beyond payload isolation, including structural damping and source vibration isolation. This report includes a brief discussion of these applications, as well as a commercialization plan for the actuator.

  13. Simulation Tool for Dielectric Barrier Discharge Plasma Actuators at Atmospheric and Sub-Atmospheric Pressures: SBIR Phase I Final Report

    Science.gov (United States)

    Likhanskii, Alexandre

    2012-01-01

    This report is the final report of a SBIR Phase I project. It is identical to the final report submitted, after some proprietary information of administrative nature has been removed. The development of a numerical simulation tool for dielectric barrier discharge (DBD) plasma actuator is reported. The objectives of the project were to analyze and predict DBD operation at wide range of ambient gas pressures. It overcomes the limitations of traditional DBD codes which are limited to low-speed applications and have weak prediction capabilities. The software tool allows DBD actuator analysis and prediction for subsonic to hypersonic flow regime. The simulation tool is based on the VORPAL code developed by Tech-X Corporation. VORPAL's capability of modeling DBD plasma actuator at low pressures (0.1 to 10 torr) using kinetic plasma modeling approach, and at moderate to atmospheric pressures (1 to 10 atm) using hydrodynamic plasma modeling approach, were demonstrated. In addition, results of experiments with pulsed+bias DBD configuration that were performed for validation purposes are reported.

  14. Defense Small Business Innovation Research Program (SBIR). Abstracts of Phase 2 Awards 1992

    Science.gov (United States)

    1992-01-01

    helicopter pop-up ,cetiario lo , ecc can be achieved. Sietitlicant features include: Hl Operates on a short data collection tinec-line. 2i 1lispothesites all...a deposition scheme. In Phase II, Aerodyne Research will grow diamond in a self-limiting fashion. Both homo - and hetero-epitaxy will be explored using

  15. Defense Small Business Innovation Research Program (SBIR). Defense Agencies Abstracts of Phase 2 Awards 1993

    Science.gov (United States)

    1993-01-01

    switching network and active Rotman lens has been parametrically investigated in Phase I. Since the Rotman lens provides true time delay azimuth scan, the...network" will be fabricated and tested to demonstrate our unique Rotman lens input port combining scheme. A "polarization selection network" will also...database management system will then be developed using algebra operators. Selected multimedia database primitives will also be implemented and evaluated

  16. Defense Small Business Innovation Research Program (SBIR). Volume 1. Army Abstracts of Phase 1 Awards 1987.

    Science.gov (United States)

    1988-04-01

    DIMENSIONAL FLOW SOLUTIONS. HORINE ENGINEERS INC PO BOX 2027 LOS GATOS , CA 95031 CONTRACT NUMBER: DAAA21-87-C-0190 CARLTON L HORINE TITLE: p IMPROVED GASKET...AN UNPARALLELED OPPORTUNITY TO SCREEN BACTERIA , FUNGI AND ALGAE FROM THERMALLY STABLE OXIDASES AND PEROXIDASES. ONCE ISOLATED, AN ATTEMPT WILL BE MADE...PROGRAM - PHASE 1 PAGE 106 BY SERVICE FISCAL YEAR 1987 ARMY SUBMITTED BY • TO DEVELOP AND TEST A SYSTEM. LASER-GENICS CORP PO BOX 33010 LOS GATOS , CA

  17. Defense Small Business Innovation Research Program (SBIR). Volume 2. Navy Abstracts of Phase 1 Awards. 1990

    Science.gov (United States)

    1990-01-01

    TRAINING. DELFIN SYSTEMS 1349 MOFFETT PARK DR 78 SMALL BUSINESS INNOVATION RESEARCH PROGRAM - PHASE I NAVY Solicitation 90.1 SUNNYVALE, CA 94089 Program...MACHINE-INTERFACES (MMI). IMPLEMENTED MMI DESIGN SHOULD REFLECT HOW THE OPERATOR ACTUALLY USES AND INTERACTS WITH THE MACHINE. DELFIN WILL ANALYZE AND...DESIGN A GENERIC EXPERT SYSTEM MMI USEFUL IN ANY DEPLOYED ESM SYSTEM. DELFIN WILL GENERICALLY DEFINE CRYPTOLOGIC SYSTEMM USE AND TECHNICAL

  18. Defense Small Business Innovation Research Program (SBIR). Abstracts of Phase I Awards. 1986.

    Science.gov (United States)

    1986-01-01

    EMPHASIS OF ANY PHASE II WORK. ANAMET LABS INC AF $ 49,031 100 INDUSTRIAL WY SAN CARLOS, CA 94070 DANTON GUTIERREZ-LFMINI TITLE: COUPLED THERMOELASTIC...NATIONAL DR - STE 280 BURTONSVILLE, MD 20866 GEORGE MAHLER TITLE: THLL BASED SYMBOLIC DEBUG FACILITY FOR VAX/VMS T 104 OFFICE: NSWC THLL IS THE TRIDENT...VALLEY RD., SUITE 112 SAN DIEGO, CA 92121 GEORGE W WEBB , TITLE: MINIATURE CONDUCTORS FOR SENSORS T 3 OFFICE: WE DESCRIBE A FOUR PART RESEARCH PROGRAM

  19. Defense Small Business Innovation Research Program (SBIR). Volume 4. Defense Agencies Abstracts of Phase 1 Awards from FY 1988 SBIR Solicitation

    Science.gov (United States)

    1989-05-01

    CORP 11180 ROSELLE ST - STE G SAN DIEGO, CA 92121 CONTRACT NUMBER: NORBERT B ELSNER TITLE: ELECTRICAL CONDUCTORS FOR 1000-2000 DEGREES K OPERATION TOPIC...DIAGNOSTIC), AND INDUSTRIAL (MATERIAL PROCESSING) USES. FELTECH 639 ROMERO CANYON RD MONTECITO, CA 93108 CONTRACT NUMBER: DR LUIS R ELIAS TITLE: HIGH

  20. Defense Small Business Innovation Research Program (SBIR). Volume 3. Air Force Projects, Abstracts of Phase 1 Awards from FY 1989 SBIR Solicitation

    Science.gov (United States)

    1990-04-01

    ALEXANDRIA, VA 22311 CONTRACT NUMBER: F19628-89-C-0127 B J STRALSER TITLE: SPECIAL OPERATIONS COMMUNICATIONS SYSTEM ( SPOCS ) TOPIC# 31 OFFICE: ESD/AVP IDENT...THAT THERE MAY BE A SINGLE SOLUTION TO FULFILLING THOSE CRITICAL REQUIREMENTS. THE SPECIAL OPERATIONS COMMUNICATION SYSTEM ( SPOCS ), USES A PULSE STREAM...PROGRAM - PHASE 1 PAGE 344 BY SERVICE FISCAL YEAR 1989 AF SUBMITTED BY THIS PROPOSAL DESCRIBES THE STEPS NECESSARY TO DEVELOP AN ONLINE GAS

  1. Defense Small Business Innovation Research Program (SBIR). Volume 2. Navy Abstracts of Phase 1 Awards 1992

    Science.gov (United States)

    1992-01-01

    field/production environments. MIKROS SYSTEMS CORP. Topic#: 92-083 ID#: 92N32-122 3490 U S ROUTE NO 1 Office: NSWCDDWO PRINCETON, NJ 08540 Contract...92-171 MIDWEST RESEARCH TECHNOLOGIES, INC. DARPA Topic#: 92-030 SDIO Topict 92-013 SDIO Topic#: 92-015 MIKROS SYSTEMS CORP. MATERIALS ANALYSIS, INC...TECHNOLOGIES, INC, PRINCETON SCIENTIFIC INSTRUMENTS, INC. ARMY Topic#: 92-040 ARMY Topic#: 92-174 RADKOWSKI ASSOC. PRO -TECH ARMY Topic#: 92-173 AF Topic#: 92

  2. Superconducting magnetic bearings for machine tools. Phase 1, SBIR program. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Anastas, G.; Bennett, A.; Downer, J.; Hockney, R.

    1988-01-01

    The research was directed toward investigating the role of superconducting materials in a magnetic bearing system. Superconducting magnetic bearings are shown to offer the potential for vastly improved performance. These bearings are expected to be especially applicable to rotors which have extremely tight position tolerances. The development of superconducting magnetic bearing technology is also expected to allow a number of novel approaches in the development of machinery and systems. Researchers studied an alternative bearing design which employs a superconducting coil and eliminates all conventional magnetic structures. The study has resulted in a design definition and detailed analysis for a superconducting bearing system which is sized to roughly duplicate the air bearing system of an existing air-bearing spindle.

  3. Report on Performance of Prototype Dynatronix Power Supplies Developed Under a Phase I DOE SBIR

    Energy Technology Data Exchange (ETDEWEB)

    Hoppe, Eric W.; Merriman, Jason H.

    2011-03-01

    The purpose of this study is to evaluate the prototype power supplies fabricated by Dynatronix, Inc. This project supports the advancement of electroforming capabilities to produce ultra-high purity copper. Ultra-high purity copper is an essential material used for a range of current and future fundamental nuclear physics programs such as the MAJORANA DEMONSTRATOR. The Mach 30 power supplies are a new design built to the specifications from the requirements of Pacific Northwest National Laboratory (PNNL) with regard to timing, voltage, current output, and the required tolerances. The parameters used in these tests were developed empirically over a number of years based on a combination of thermodynamic and kinetics of the electroplating process. The power supplies were operated in a typical cleanroom environment for the production electroforming at PNNL. The units that were received by PNNL in July, 2010 have performed satisfactorily and have demonstrated short term durability.

  4. SBIR/STTR Programs

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA SBIR and STTR programs fund the research, development, and demonstration of innovative technologies that fulfill NASA needs as described in the annual...

  5. A Fire Safety Certification System for Board and Care Operators and Staff. SBIR Phase I: Final Report.

    Science.gov (United States)

    Walker, Bonnie L.

    This report describes the development and pilot testing of a fire safety certification system for board and care operators and staff who serve clients with developmental disabilities. During Phase 1, training materials were developed, including a trainer's manual, a participant's coursebook a videotape, an audiotape, and a pre-/post test which was…

  6. Defense Small Business Innovation Research Program (SBIR). Volume 4. Defense Agencies Abstracts of Phase 1 Awards 1987.

    Science.gov (United States)

    1988-04-01

    CHANNEL) . THE -0 SMALL BUSINESS INNOVATION RESEARCH ( SBR ) PROGRAM - PHASE I PAGE 628 0 BY SERVICE FISCAL YEAR 1987 DNA SJBMTTFD BY NATURE OF THE...OXYGEN CONTAMINATION. THEIR HIGH PYROLYSIS TEMPERATURES CAUSE PROBLEMS SUCH AS INABILITY TO CONTROL THE AS/P RATIO IN ALLOYS CONTAINING BOTH ELEMENTS...LUBRICITY. GRAPHITE FIBER GROWN FROM PYROLYSIS OF HYDROCARBON GAS, WHICH IS THEN PROCESSED TO YIELD USEFUL VALUES FOR ELECTRICAL CONDUCTIVITY, IS A MATERIAL

  7. Final Report: DoE SBIR Phase 2 Low-Cost Small Diameter NMR Technologies for In-Situ Subsurface Characterization and Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, David Oliver [Vista Clara Inc., Mukilteo, WA (United States)

    2010-09-03

    In this Phase 2 SBIR program, Vista Clara successfully developed and field-tested small diameter NNR logging tools for subsurface characterization and monitoring. This effort involved the design and development surface electronics, a winch with 470ft cable, and three interchangeable downhole probes: a 3.5â diameter borehole NMR probe, a 1.67â diameter borehole NMR probe, and a 2.5â diameter NMR probe that can be deployed using a Geoprobe direct push machine. The 3.5â probe was tested extensively over a 6 week period including 4â to 8â boreholes in Washington, Idaho, Nebraska, Colorado, Kansas, Connecticut and Massachusetts. The field test campaign was highly successful. The 1.67â probe was assembled, tested and calibrated in the laboratory. The 2.5â Geoprobe probe is in final assembly and testing at the time of this report. The completed Phase 2 R&D program has resulted in the first NMR logging tool that can be deployed in boreholes of 4â diameter, the first NMR logging tool that can be deployed in boreholes on 2â diameter, and the first NMR logging tool that can be deployed by a direct push machine. These small diameter tools make NMR logging technically and economically feasible, for the first time. Previously available NMR logging tools were developed for oilfield applications and are prohibitively large and expensive for the majority of near surface groundwater characterization problems.

  8. DOE SBIR Phase-1 Report on Hybrid CPU-GPU Parallel Development of the Eulerian-Lagrangian Barracuda Multiphase Program

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Dale M. Snider

    2011-02-28

    This report gives the result from the Phase-1 work on demonstrating greater than 10x speedup of the Barracuda computer program using parallel methods and GPU processors (General-Purpose Graphics Processing Unit or Graphics Processing Unit). Phase-1 demonstrated a 12x speedup on a typical Barracuda function using the GPU processor. The problem test case used about 5 million particles and 250,000 Eulerian grid cells. The relative speedup, compared to a single CPU, increases with increased number of particles giving greater than 12x speedup. Phase-1 work provided a path for reformatting data structure modifications to give good parallel performance while keeping a friendly environment for new physics development and code maintenance. The implementation of data structure changes will be in Phase-2. Phase-1 laid the ground work for the complete parallelization of Barracuda in Phase-2, with the caveat that implemented computer practices for parallel programming done in Phase-1 gives immediate speedup in the current Barracuda serial running code. The Phase-1 tasks were completed successfully laying the frame work for Phase-2. The detailed results of Phase-1 are within this document. In general, the speedup of one function would be expected to be higher than the speedup of the entire code because of I/O functions and communication between the algorithms. However, because one of the most difficult Barracuda algorithms was parallelized in Phase-1 and because advanced parallelization methods and proposed parallelization optimization techniques identified in Phase-1 will be used in Phase-2, an overall Barracuda code speedup (relative to a single CPU) is expected to be greater than 10x. This means that a job which takes 30 days to complete will be done in 3 days. Tasks completed in Phase-1 are: Task 1: Profile the entire Barracuda code and select which subroutines are to be parallelized (See Section Choosing a Function to Accelerate) Task 2: Select a GPU consultant company and

  9. Feasibility of an Integrated Expert Video Authoring Workstation for Low-Cost Teacher Produced CBI. SBIR Phase I: Final Report.

    Science.gov (United States)

    IntelliSys, Inc., Syracuse, NY.

    This was Phase I of a three-phased project. This phase of the project investigated the feasibility of a computer-based instruction (CBI) workstation, designed for use by teachers of handicapped students within a school structure. This station is to have as a major feature the ability to produce in-house full-motion video using one of the…

  10. A Fire Safety Certification System for Board and Care Operators and Staff. SBIR Phase II: Final Report.

    Science.gov (United States)

    Walker, Bonnie L.

    This report describes Phase II of a project which developed a system for delivering fire safety training to board and care providers who serve adults with developmental disabilities. Phase II focused on developing and pilot testing a "train the trainers" workshop for instructors and field testing the provider's workshop. Evaluation of the 2-day…

  11. Defense Small Business Innovation Research Program (SBIR). Volume 3. Air Force Abstracts of Phase 1 Awards 1993

    Science.gov (United States)

    1993-01-01

    Vapor Phase Epitaxy Abstract: Brimrose Corporation, Phase I objective is to use the in house developed " multipolar " low temperature/low energy, mixed...the number of neurons in the filter increases. All the three main formulations for the INS and GPS integration, namely the direct, indirect feed...INTELLIGENT NEURONS , INC. ARMY Topic#: 92-046 BMDO Topic#: 93-011 JC ASSOC. INTELLIGENT REASONING SYSTEMS BMDO Topic#: 93-013 ARMY Topic#: 92-172 BMDO

  12. Space Compatible Radar Absorbing Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase 1 project shall investigate novel radar absorbing materials (RAM) for use in space or simulated space environments. These materials are lightweight...

  13. Defense Small Business Innovation Research Program (SBIR). Volume 3. Air Force Abstracts of Phase 1 Awards 1991

    Science.gov (United States)

    1991-01-01

    computational faibility via implementation on massively parallel neural networks. The phase I investigation will asess the exten of exploitable spectral...feature extraction, including neural net based multiresolution classifiers. Overall system performance will be computed analytically and through...robustness of the gas bearing system in the tubo -compresor over the range of anticipated operation. CRYSTAL ASSOC., INC. Topic: 91-119 1.91WM 15

  14. Defense Small Business Innovation Research Program (SBIR). Volume 3. Air Force Abstracts of Phase 1 Awards 1987.

    Science.gov (United States)

    1988-04-01

    FEATURES. CARE WILL BE TAKEN SO THAT OPTIMIZATIONS ARE NOT SPECIFIC TO PARTI- - . CULAR TARGET MACHINES. TAU CORP 485 ALBERTO WY - BLDG D LOS GATOS , CA...CORPORATION’S INTEGRATED NAVIGATION SYSTEM SIMULATION. TAU CORP 485 ALBERTO WY - BLDG D LOS GATOS , CA 95030 CONTRACT NUMBER: F33615-87-C-0193 PATRICK CIGANER...PENETRATED BY BACTERIA AND SAFELY REMOVED FROM THE ALUMINUM AND TITANIUM ALLOYS AS WELL AS OTHER CARBON FIBER OR COMPOSITE MATERIALS. TECHNOCHEM CO PO BOX

  15. GRAIL-genQuest: A comprehensive computational system for DNA sequence analysis. Final report, DOE SBIR Phase II

    Energy Technology Data Exchange (ETDEWEB)

    Manning, Ruth Ann

    1999-01-05

    {trademark} Network Edition and ApoCom GRAIL{trademark} Personal Edition, have been developed to reach two diverse niche markets in the Phase III commercialization of this software. As a result of this project ApoCom GRAIL{trademark} can now be made available to the desktop (UNIX{reg_sign}, Windows{reg_sign} 95 and Windows NT{reg_sign}, or Mac{trademark} 0S) of any researcher who needs it.

  16. Directed reflectivity, long life AMTEC condenser (DRC). Final report of Phase II SBIR program[Alkali Metal ThermoElectric Converter

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, Thomas K.

    2001-09-10

    more effective than on the condenser end surface itself. The experimental work in Phase 2 was intended to incorporate a DRC into this cell design and use its measured performance to refine the state-of-the-art AMTEC analytical models. Because the analysis had indicated that the new radial converter design, which may be useful for systems at the {approx} 100 watt level was not much assisted by the DRC properties, this program was redirected toward the simpler cylindrical converter design with the corner cube surfaces on the side walls. The Phase II program was proposed and planned with a funding level substantially below the maximum potentially available for Phase II programs at that time. At the time, there were two other funded government sponsored programs at AMPS for which positive results of the analyses described in this report were expected to lead to incorporation of the DRC concept into converters scheduled to be built for these programs. The programs of interest were the Air Force program titled ''Radiation Tolerant, Eclipse Compatible, Solar AMTEC System'' (F29601-99-C-0132) and the DOE/NASA Advanced Radioisotope Power System (ARPS) program. Shortly after its start, the Air Force program was canceled due to elimination of AF SBIR funds at AFRL and the ARPS program was reduced to a level that could not support introduction of novel concept testing. As a result of these two circumstances, the direct testing of the DRC concept in a full up converter was not completed in the Phase II period.

  17. Moisture-resistant TPS Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed NASA Phase I SBIR will generate closed-cell foam thermal protection system materials which do not need waterproofing, and which can be applied as a...

  18. KSC SBIR/STTR 2004 Program Year Report

    Science.gov (United States)

    2005-01-01

    The Kennedy Space Center Level III SBIR/STTR management staff is under the Technology Transfer Office within the Spaceport Engineering and Technology Directorate. The SBIR and STTR programs provide an opportunity for small high technology companies and research institutions to participate in Government-sponsored research and development (R&D) programs in key technology areas. The SBIR program was established by Congress in 1982 to provide increased opportunities for small businesses to participate in R&D programs, increase employment, and improve U.S. competitiveness. The program's specific objectives are to stimulate U.S. technological innovation, use small businesses to meet Federal research and development needs, increase private sector commercialization of innovations, and foster and encourage participation by socially disadvantaged businesses. Legislation enacted in December 2000 reauthorized the program and strengthened emphasis on pursuing commercial applications of SBIR projects. An SBIR Phase I contract is the opportunity to establish the feasibility and technical merit of a proposed innovation. Selected competitively, the Phase I contract lasts for 6 months and is funded up to $70,000. SBIR Phase II contracts continue the most promising Phase I projects based on scientific! technical merit, expected value to NASA, company capability, and commercial potential. Phase II contracts are usually for a period of 24 months and may not exceed $600,000. NASA usually selects approximately 40 percent of Phase I projects to continue to the Phase II level. Phase III is the process of furthering the development of a product to make it commercially available. The STTR program awards contracts to small business concerns for cooperative R&D with a nonprofit research institution. Research institutions include nonprofit research organizations, Federal laboratories, or universities. The goal of the program established by Congress is to facilitate the transfer of technology

  19. Sputter-Resistant Materials for Electric Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase 2 project shall develop sputter-resistant materials for use in electric propulsion test facilities and for plume shields on spacecraft using electric...

  20. Nanoscale phase change memory materials.

    Science.gov (United States)

    Caldwell, Marissa A; Jeyasingh, Rakesh Gnana David; Wong, H-S Philip; Milliron, Delia J

    2012-08-01

    Phase change memory materials store information through their reversible transitions between crystalline and amorphous states. For typical metal chalcogenide compounds, their phase transition properties directly impact critical memory characteristics and the manipulation of these is a major focus in the field. Here, we discuss recent work that explores the tuning of such properties by scaling the materials to nanoscale dimensions, including fabrication and synthetic strategies used to produce nanoscale phase change memory materials. The trends that emerge are relevant to understanding how such memory technologies will function as they scale to ever smaller dimensions and also suggest new approaches to designing materials for phase change applications. Finally, the challenges and opportunities raised by integrating nanoscale phase change materials into switching devices are discussed.

  1. Next Generation , Lightweight, Durable Boot Materials to Provide Active & Passive Thermal Protection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this NASA Phase I SBIR program is to leverage lightweight, durable materials developed by NanoSonic for use within extra vehicular activity (EVA)...

  2. Next Generation Advanced Binder Chemistries for High Performance, Environmentally DurableThermal Control Material Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This innovative SBIR Phase II proposal will develop next generation products for Thermal Control Material Systems (TCMS) an adhesives based on the next generation...

  3. Wireless Sensor Needs Defined by SBIR Topics

    Science.gov (United States)

    Studor, George F.

    2010-01-01

    This slide presentation reviews the needs for wireless sensor technology from various U.S. government agencies as exhibited by an analysis of Small Business Innovation Research (SBIR) solicitations. It would appear that a multi-agency group looking at overlapping wireless sensor needs and technology projects is desired. Included in this presentation is a review of the NASA SBIR process, and an examination of some of the SBIR projects from NASA, and other agencies that involve wireless sensor development

  4. NASA Johnson Space Center SBIR STTR Program Technology Innovations

    Science.gov (United States)

    Krishen, Kumar

    2007-01-01

    The Small Business Innovation Research (SBIR) Program increases opportunities for small businesses to participate in research and development (R&D), increases employment, and improves U.S. competitiveness. Specifically the program stimulates U.S. technological innovation by using small businesses to meet federal R&D needs, increasing private-sector commercialization of innovations derived from federal R&D, and fostering and encouraging the participation of socially disadvantaged businesses. In 2000, the Small Business Technology Transfer (STTR) Program extended and strengthened the SBIR Program, increasing its emphasis on pursuing commercial applications by awarding contracts to small business concerns for cooperative R&D with a nonprofit research institution. Modeled after the SBIR Program, STTR is nevertheless a separately funded activity. Technologies that have resulted from the Johnson Space Center SBIR STTR Program include: a device for regenerating iodinated resin beds; laser-assisted in-situ keratomileusis or LASIK; a miniature physiological monitoring device capable of collecting and analyzing a multitude of real-time signals to transmit medical data from remote locations to medical centers for diagnosis and intervention; a new thermal management system for fibers and fabrics giving rise to new line of garments and thermal-enhancing environments; and a highly electropositive material that attracts and retains electronegative particles in water.

  5. Photometrical Observations "SBIRS GEO-2"

    Science.gov (United States)

    Sukhov, P. P.; Epishev, V. P.; Karpenko, G. F.; Sukhov, K. P.; Kudak, V. I.

    Photometrical observations GSS "SBIRS GEO 2" in B,V,R filters were carried near the equinoxes 2014-2015. Used velocity electrophotometer based on the FEU-79 in the pulse-counting mode. Received more than 25 light curves. From the known dimensions are defined; effective reflecting area - Sγλ, the spectral reflectance index - γλ, periods of light variation. Color-indices showed that in the reflected light flux from the GSS prevails "red" component. In the light curves are periodically dips and specular flash. This shows that GSS orbit is not in a static position specified triaxial orientation as in dynamic motion. Assumed following dynamics of the satellite "SBIRS GEO 2" in orbit. Helical scanning the Earth's surface visible infrared sensors satellite occurs with a period P1 = 15.66 sec. and swinging of the GSS about the direction of the motion vector of the satellite in an orbit with P2 = 62.64 sec., from the northern to the southern pole. Thus, during the period of swinging GSS going on 2 scan the visible part of the northern and southern hemispheres. In some dates observations dynamics work satellite in orbit changed.

  6. Space Based Infrared System High (SBIRS High)

    Science.gov (United States)

    2015-12-01

    Aviation Blvd Bldg 271 Los Angeles Air Force Base (LAAFB) El Segundo, CA 90245-2808 michael.guetlein@us.af.mil Phone: 310-653-3018 Fax: 310-653-4414 DSN...mission areas: Missile Warning , Missile Defense, Technical Intelligence and Battlespace Awareness. The constellation architecture for SBIRS High...Integrated Tactical Warning /Attack Assessment (ITW/AA) mission in November 2008 and technical intelligence mission in August 2009. The SBIRS GEO 1

  7. Polymers in phase change materials

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, M.C.; Brites, M.J.; Alexandre, J.H. [National Lab. for Energy and Geology, Lisbon (Portugal)

    2010-07-01

    Phase Change Materials (PCMs) which are the core of latent heat thermal energy storage systems are currently an area of investigation of increasing interest. Several substances differing in physical and chemical characteristics as well as in thermal behavior have been studied as PCMS{sup 1-3}. In order to meet the requisites of particular systems, auxiliary materials are often used with specific functions. This bibliographic survey shows that polymeric materials have been proposed either as the PCM itself in solid-liquid or solid-solid transitions or to perform auxiliary functions of shape stabilisation and microencapsulation for solid-liquid PCMs. The PCMs have an operating temperature ranging from around 0 C (for the system water/polyacrilamid) to around 127 C (for crosslinked HDPE). (orig.)

  8. Vapor Chamber with Phase Change Material-based Wick Structure for Thermal Control of Manned Spacecraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In response to NASA SBIR solicitation H3.01 "Thermal Control for Future Human Exploration", Advanced Cooling Technologies, Inc. (ACT) is proposing a novel Phase...

  9. Technology Development Report: CDDF, Dual Use Partnerships, SBIR/STTR: Fiscal Year 2003 Activities

    Science.gov (United States)

    Bailey, John W.

    2004-01-01

    The FY2003 NASA John C. Stennis Stennis Space Center (SSC) Technology Development Report provides an integrated report of all technology development activities at SSC. This report actually combines three annual reports: the Center Director's Discretionary Fund (CDDF) Program Report, Dual Use Program Report, and the Small Business Innovation Research (SBIR)/Small Business Technology Transfer (STTR) Program Report. These reports are integrated in one document to summarize all technology development activities underway in support of the NASA missions assigned to SSC. The Dual Use Program Report provides a summary review of the results and status of the nine (9) Dual Use technology development partnership projects funded and managed at SSC during FY2003. The objective of these partnership projects is to develop or enhance technologies that will meet the technology needs of the two NASA SSC Mission Areas: Propulsion Test and Earth Science Applications. During FY2003, the TDTO managed twenty (20) SBIR Phase II Projects and two (2) STTR Phase II Projects. The SBIR contracts support low TRL technology development that supports both the Propulsion Test and the Earth Science Application missions. These projects are shown in the SBIR/STTR Report. In addition to the Phase II contracts, the TDTO managed ten (10) SBIR Phase I contracts which are fixed price, six month feasibility study contracts. These are not listed in this report. Together, the Dual Use Projects and the SBIR/STTR Projects constitute a technology development partnership approach that has demonstrated that success can be achieved through the identification of the technical needs of the NASA mission and using various available partnership techniques to maximize resource utilization to achieve mutual technology goals. Greater use of these partnership techniques and the resource leveraging they provide, is a goal of the TDTO, providing more support to meet the technology development needs of the mission areas at

  10. Phase change materials science and applications

    CERN Document Server

    Raoux, Simone

    2009-01-01

    ""Phase Change Materials: Science and Applications"" provides a unique introduction of this rapidly developing field. This clearly written volume describes the material science of these fascinating materials from a theoretical and experimental perspective.

  11. Database and Management Information Support for the U.S. Army SBIR program

    Science.gov (United States)

    1994-06-10

    144,206 autostereoscopic video ...................................................... 139 beam processing...SOLICITATION DATA 3a. Total Number of Phase I SBIR Solicitations Released 3b. Identification Number of the Solicitation 3c. Date of Solicitation Released 3d ...decision aids, touch screens, 3D visualizations, and virtual representations. The display included the ability to monitor missile tests of four missiles

  12. PCM Concrete. [Phase Change Materials

    Energy Technology Data Exchange (ETDEWEB)

    Juul Andersen, T. [Danish Technological Institute, Taastrup (Denmark); Poulsen, H.-H. [BASF A/S, Roedekro (Denmark); Passov, F. [Spaencom A/S, Hedehusene (Denmark); Heiselberg, P. [Aalborg Univ..Aalborg (Denmark)

    2013-04-01

    PCM-Concrete was a research and development project launched in 2009 and finished in 2012. The project, which was funded by The Danish National Advanced Technology Foundation, had a total budget of 1.7 million Euros and included 4 partners: Danish Technological Institute (project manager), Aalborg University, BASF A/S and Spaencom A/S. The overall vision of the project was to reduce energy consumption for heating and cooling in buildings by developing high-performance concrete structures microencapsulated Phase Change Materials (PCM). The PCM used in the project was Micronal produced by BASF A/S. Micronal is small capsules with an acrylic shell and inside a wax with a melting point at approx. 23 deg. C equal to a comfortable indoor temperature. During the melting process thermal energy is transferred to chemical reaction (melting/solidification) depending on PCM being heated up or cooled down. Adding Micronal to concrete would theoretically increase the thermal mass of the concrete and improve the diurnal heat capacity which is the amount of energy that can be stored and released during 24 hours. Nevertheless, it is a relatively new technology that has not received much attention, yet. In the PCM-Concrete project 5 main investigations were carried out: 1) Development of concrete mix design with PCM. 2) Investigation of thermal properties of the PCM concrete: thermal conductivity, specific heat capacity, density. 3) Up-scaling the research to industrial production of PCM-concrete structures. 4) Testing energy efficiency in full scale. 5) Confronting aesthetic and acoustic barriers to full exploitation of the potential of PCM-concrete structures. The results from the test program showed: 1) That the diurnal heat storage capacity is higher for all 4 hollow core decks with tiles attached compared to the reference hollow core deck. 2) The hollow core decks with concrete tiles without PCM performs slightly better than the tiles with PCM. 3) That is was impossible to

  13. Lightweight solar concentrator structures, phase 2

    Science.gov (United States)

    Williams, Brian E.; Kaplan, Richard B.

    1993-01-01

    This report summarizes the results of the program conducted by Ultramet under SBIR Phase 2 Contract NAS3-25418. The objective of this program was to develop lightweight materials and processes for advanced high accuracy Space Solar Concentrators using rigidized foam for the substrate structure with an integral optical surface.

  14. Research on microcapsules of phase change materials

    Institute of Scientific and Technical Information of China (English)

    DAI Xia; SHEN Xiaodong

    2006-01-01

    Microcapsule technology is a kind of technology wrapping the solid or liquid into minute-sized particles within the field of micrometer or millimeter with film forming materials. This thesis introduces microcapsule technology of phase change materials and its main functions and the structural composition, preparation methods and characterization technology of microcapsule of phase change materials. The microcapsule of phase change materials is small in size and its temperature remains unchanged during the process of heat absorption and heat release. It is of great value in research and application prospect due to these characteristics.

  15. Nuclear Concrete Materials Database Phase I Development

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Weiju [ORNL; Naus, Dan J [ORNL

    2012-05-01

    The FY 2011 accomplishments in Phase I development of the Nuclear Concrete Materials Database to support the Light Water Reactor Sustainability Program are summarized. The database has been developed using the ORNL materials database infrastructure established for the Gen IV Materials Handbook to achieve cost reduction and development efficiency. In this Phase I development, the database has been successfully designed and constructed to manage documents in the Portable Document Format generated from the Structural Materials Handbook that contains nuclear concrete materials data and related information. The completion of the Phase I database has established a solid foundation for Phase II development, in which a digital database will be designed and constructed to manage nuclear concrete materials data in various digitized formats to facilitate electronic and mathematical processing for analysis, modeling, and design applications.

  16. Photometrical research geostationary satellite "SBIRS GEO-2"

    Science.gov (United States)

    Sukhov, P. P.; Epishev, V. P; Sukhov, K. P; Kudak, V. I.

    The multicolor photometrical observations GSS "Sbirs Geo-2" were carried in B,V,R filters out during the autumn equinox 2014 and spring 2015 y. Periodic appearance of many light curves and dips of mirror reflections suggests that the GSS was not in orbit in a static position, predetermined three-axis orientation and in dynamic motion. On the basis of computer modeling suggests the following dynamics GSS "Sbirs Geo-2" in orbit. Helically scanning the visible Earth's surface infrared satellite sensors come with period P1 = 15.66 sec. and the rocking of the GSS about the direction of the motion vector of the satellite in orbit with P2 = 62.64 sec., most likely with the purpose to survey the greatest possible portion of the earth's surface.

  17. Heat transfer in multi-phase materials

    CERN Document Server

    Öchsner, Andreas

    2011-01-01

    This book provides a profound understanding, which physical processes and mechanisms cause the heat transfer in composite and cellular materials. It shows models for all important classes of composite materials and introduces into the latest advances. In three parts, the book covers Composite Materials (Part A), Porous and Cellular Materials (Part B) and the appearance of a conjoint solid phase and fluid aggregate (Part C).

  18. SBIR Final Report. Liquid Core Optical Scintillating Fibers

    Energy Technology Data Exchange (ETDEWEB)

    Beetz, C.P.; Steinbeck, J.; Buerstler, R.

    2000-05-16

    This Phase I SBIR project focused on developing flexible scintillating liquid core optical fibers, with potential uses in high-energy calorimetry, tracking, preradiators, active targets or other fast detectors. Progress on the six tasks of the project is summarized. The technical developments involve three technology components: (1) highly flexible capillaries or tubes of relatively low n (index of refraction) to serve as cladding and liquid core containment; (2) scintillator (and clear) fluids of relatively high n to serve as a core-- these fluids must have a high light transmission and, for some applications, radiation hardness; (3) optical end plugs, plug insertion, and plug-cladding tube sealing technology to contain the core fluids in the tubes, and to transmit the light.

  19. Phase transformations, stability, and materials interactions

    Energy Technology Data Exchange (ETDEWEB)

    Morris, J.W. Jr.; Brewer, L.; Cost, J.R.; Shewmon, P.

    1977-07-01

    The proceedings of the Materials Sciences Workshop on Phase Transformations, Stability, and Materials Interactions are divided into sections according to the following topics: (I) workshop scope and priorities; (II) study group reports--ERDA mission needs; (III) study group reports--technical area research priorities. (SDF)

  20. Small business innovation research. Abstracts of 1988 phase 1 awards

    Science.gov (United States)

    1990-01-01

    Non-proprietary proposal abstracts of Phase 1 Small Business Innovation Research (SBIR) projects supported by NASA are presented. Projects in the fields of aeronautical propulsion, aerodynamics, acoustics, aircraft systems, materials and structures, teleoperators and robots, computer sciences, information systems, data processing, spacecraft propulsion, bioastronautics, satellite communication, and space processing are covered.

  1. Thermal Energy Storage with Phase Change Material

    Directory of Open Access Journals (Sweden)

    Lavinia Gabriela SOCACIU

    2012-08-01

    Full Text Available Thermal energy storage (TES systems provide several alternatives for efficient energy use and conservation. Phase change materials (PCMs for TES are materials supplying thermal regulation at particular phase change temperatures by absorbing and emitting the heat of the medium. TES in general and PCMs in particular, have been a main topic in research for the last 30 years, but although the information is quantitatively enormous, it is also spread widely in the literature, and difficult to find. PCMs absorb energy during the heating process as phase change takes place and release energy to the environment in the phase change range during a reverse cooling process. PCMs possesses the ability of latent thermal energy change their state with a certain temperature. PCMs for TES are generally solid-liquid phase change materials and therefore they need encapsulation. TES systems using PCMs as a storage medium offers advantages such as high TES capacity, small unit size and isothermal behaviour during charging and discharging when compared to the sensible TES.

  2. Caloric materials near ferroic phase transitions

    Science.gov (United States)

    Moya, X.; Kar-Narayan, S.; Mathur, N. D.

    2014-05-01

    A magnetically, electrically or mechanically responsive material can undergo significant thermal changes near a ferroic phase transition when its order parameter is modified by the conjugate applied field. The resulting magnetocaloric, electrocaloric and mechanocaloric (elastocaloric or barocaloric) effects are compared here in terms of history, experimental method, performance and prospective cooling applications.

  3. Magnetocaloric materials and first order phase transitions

    DEFF Research Database (Denmark)

    Neves Bez, Henrique

    of the properties of such materials.The experimental characterization of these materials is done through various different methods, such as X-ray diffraction, magnetometry, calorimetry, direct measurements of entropy change, capacitance dilatometry, scanning electron microscopy,energy-dispersive X-ray spectrometry......This thesis studies the first order phase transitions of the magnetocaloric materials La0.67Ca0.33MnO3 and La(Fe,Mn,Si)13Hz trying to overcome challenges that these materials face when applied in active magnetic regenerators. The study is done through experimental characterization and modelling...... and magnetocaloric regenerative tests. The magnetic, thermal and structural properties obtained from such measurements are then evaluated through different models, i.e. the Curie-Weiss law, the Bean-Rodbell model, the free electron model and the Debye model.The measured magnetocaloric properties of La0.67Ca0.33MnO3...

  4. Transitional Phenomena on Phase Change Materials

    Directory of Open Access Journals (Sweden)

    Wójcik Tadeusz M.

    2014-03-01

    Full Text Available One of the most significant problem with technology development is transferring of large heat fluxes, which requires constant heat transfer temperature (in the specified temperature range. This problem concern mainly the nuclear energetics, space technologies, military technologies and most of all electronics containing integrated circuits with very large scale of integrations. Intensive heat transfer and thermal energy storage are possible by the use of phase change materials (PCMs. In the paper there are presented preliminary results of research on the use of liquid-gas (L-G PCMs and solid-solid phase change materials (S-S PCMs. For L-G PCMs the boiling characteristics were determined by increasing and decreasing the heat flux, which for certain sets of structural parameters of the heating surface and the physical properties of the liquid induce a variety of forms of transitional phenomena. Thermal energy storage is much more effective when using PCMs than sensible heat.

  5. Small business innovation research. Abstracts of completed 1987 phase 1 projects

    Science.gov (United States)

    1989-01-01

    Non-proprietary summaries of Phase 1 Small Business Innovation Research (SBIR) projects supported by NASA in the 1987 program year are given. Work in the areas of aeronautical propulsion, aerodynamics, acoustics, aircraft systems, materials and structures, teleoperators and robotics, computer sciences, information systems, spacecraft systems, spacecraft power supplies, spacecraft propulsion, bioastronautics, satellite communication, and space processing are covered.

  6. Phase change material thermal capacitor clothing

    Science.gov (United States)

    Buckley, Theresa M. (Inventor)

    2005-01-01

    An apparatus and method for metabolic cooling and insulation of a user in a cold environment. In its preferred embodiment the apparatus is a highly flexible composite material having a flexible matrix containing a phase change thermal storage material. The apparatus can be made to heat or cool the body or to act as a thermal buffer to protect the wearer from changing environmental conditions. The apparatus may also include an external thermal insulation layer and/or an internal thermal control layer to regulate the rate of heat exchange between the composite and the skin of the wearer. Other embodiments of the apparatus also provide 1) a path for evaporation or direct absorption of perspiration from the skin of the wearer for improved comfort and thermal control, 2) heat conductive pathways within the material for thermal equalization, 3) surface treatments for improved absorption or rejection of heat by the material, and 4) means for quickly regenerating the thermal storage capacity for reuse of the material. Applications of the composite materials are also described which take advantage of the composite's thermal characteristics. The examples described include a diver's wet suit, ski boot liners, thermal socks, gloves and a face mask for cold weather activities, and a metabolic heating or cooling blanket useful for treating hypothermia or fever patients in a medical setting and therapeutic heating or cooling orthopedic joint supports.

  7. Electrical transport in crystalline phase change materials

    Energy Technology Data Exchange (ETDEWEB)

    Woda, Michael

    2012-01-06

    In this thesis, the electrical transport properties of crystalline phase change materials are discussed. Phase change materials (PCM) are a special class of semiconducting and metallic thin film alloys, typically with a high amount of the group five element antimony or the group six element tellurium, such as Ge{sub 2}Sb{sub 2}Te{sub 5}. The unique property portfolio of this material class makes it suitable for memory applications. PCMs reveal fast switching between two stable room-temperature phases (amorphous and crystalline) realized by optical laser or electrical current pulses in memory devices. Additionally, a pronounced property contrast in form of optical reflectivity and electrical conductivity between the amorphous and crystalline phase is the characteristic fingerprint of PCMs. The emerging electrical solid state memory PCRAM is a very promising candidate to replace Flash memory in the near future or to even become a universal memory, which is non-volatile and shows the speed and cyclability of DRAM. One of the main technological challenges is the switching process into the amorphous state, which is the most power demanding step. In order to reduce the switching power, the crystalline resistivity needs to be increased at a given voltage. Thus understanding and tayloring of this property is mandatory. In this work, first the technological relevance, i.e. optical and electrical memory concepts based on PCMs are introduced. Subsequently a description of the physical properties of PCMs in four categories is given. Namely, structure, kinetics, optical properties and electrical properties are discussed. Then important recent developments such as the identification of resonant bonding in crystalline PCMs and a property predicting coordination scheme are briefly reviewed. The following chapter deals with the theoretical background of electrical transport, while the next chapter introduces the experimental techniques: Sputtering, XRR, XRD, DSC, thermal annealing

  8. Material Engineering for Phase Change Memory

    Science.gov (United States)

    Cabrera, David M.

    As semiconductor devices continue to scale downward, and portable consumer electronics become more prevalent there is a need to develop memory technology that will scale with devices and use less energy, while maintaining performance. One of the leading prototypical memories that is being investigated is phase change memory. Phase change memory (PCM) is a non-volatile memory composed of 1 transistor and 1 resistor. The resistive structure includes a memory material alloy which can change between amorphous and crystalline states repeatedly using current/voltage pulses of different lengths and magnitudes. The most widely studied PCM materials are chalcogenides - Germanium-Antimony-Tellerium (GST) with Ge2Sb2Te3 and Germanium-Tellerium (GeTe) being some of the most popular stochiometries. As these cells are scaled downward, the current/voltage needed to switch these materials becomes comparable to the voltage needed to sense the cell's state. The International Roadmap for Semiconductors aims to raise the threshold field of these devices from 66.6 V/mum to be at least 375 V/mum for the year 2024. These cells are also prone to resistance drift between states, leading to bit corruption and memory loss. Phase change material properties are known to influence PCM device performance such as crystallization temperature having an effect on data retention and litetime, while resistivity values in the amorphous and crystalline phases have an effect on the current/voltage needed to write/erase the cell. Addition of dopants is also known to modify the phase change material parameters. The materials G2S2T5, GeTe, with dopants - nitrogen, silicon, titanium, and aluminum oxide and undoped Gallium-Antimonide (GaSb) are studied for these desired characteristics. Thin films of these compositions are deposited via physical vapor deposition at IBM Watson Research Center. Crystallization temperatures are investigated using time resolved x-ray diffraction at Brookhaven National Laboratory

  9. Passive thermal management using phase change materials

    Science.gov (United States)

    Ganatra, Yash Yogesh

    The trend of enhanced functionality and reducing thickness of mobile devices has. led to a rapid increase in power density and a potential thermal bottleneck since. thermal limits of components remain unchanged. Active cooling mechanisms are not. feasible due to size, weight and cost constraints. This work explores the feasibility. of a passive cooling system based on Phase Change Materials (PCMs) for thermal. management of mobile devices. PCMs stabilize temperatures due to the latent heat. of phase change thus increasing the operating time of the device before threshold. temperatures are exceeded. The primary contribution of this work is the identification. of key parameters which influence the design of a PCM based thermal management. system from both the experiments and the numerical models. This work first identifies strategies for integrating PCMs in an electronic device. A. detailed review of past research, including experimental techniques and computational. models, yields key material properties and metrics to evaluate the performance of. PCMs. Subsequently, a miniaturized version of a conventional thermal conductivity. measurement technique is developed to characterize thermal resistance of PCMs. Further, latent heat and transition temperatures are also characterized for a wide. range of PCMs. In-situ measurements with PCMs placed on the processor indicate that some. PCMs can extend the operating time of the device by as much as a factor of 2.48. relative to baseline tests (with no PCMs). This increase in operating time is investigated. by computational thermal models that explore various integration locations, both at the package and device level.

  10. Phase Change Material Thermal Power Generator

    Science.gov (United States)

    Jones, Jack A.

    2013-01-01

    An innovative modification has been made to a previously patented design for the Phase Change Material (PCM) Thermal Generator, which works in water where ocean temperature alternatively melts wax in canisters, or allows the wax to re-solidify, causing high-pressure oil to flow through a hydraulic generator, thus creating electricity to charge a battery that powers the vehicle. In this modification, a similar thermal PCM device has been created that is heated and cooled by the air and solar radiation instead of using ocean temperature differences to change the PCM from solid to liquid. This innovation allows the device to use thermal energy to generate electricity on land, instead of just in the ocean.

  11. 77 FR 46909 - Small Business Innovation Research (SBIR) Program and Small Business Technology Transfer (STTR...

    Science.gov (United States)

    2012-08-06

    ... Innovation Research (SBIR) Program and Small Business Technology Transfer (STTR) Program Policy Directives... Small Business Innovation Research (SBIR) and Small Business Technology Transfer Program (STTR) Policy... technology@sba.gov . SUPPLEMENTARY INFORMATION: I. Background Information SBA is publishing Policy Directives...

  12. Interfacial Design of Composite Ablative Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research (SBIR) project proposes the development of a computational software package to provide NASA with advanced materials...

  13. Phase Change Material Heat Exchanger Life Test

    Science.gov (United States)

    Lillibridge, Sean; Stephan, Ryan

    2009-01-01

    Low Lunar Orbit (LLO) poses unique thermal challenges for the orbiting space craft, particularly regarding the performance of the radiators. The IR environment of the space craft varies drastically from the light side to the dark side of the moon. The result is a situation where a radiator sized for the maximal heat load in the most adverse situation is subject to freezing on the dark side of the orbit. One solution to this problem is to implement Phase Change Material (PCM) Heat Exchangers. PCM Heat Exchangers act as a "thermal capacitor," storing thermal energy when there is too much being produced by the space craft to reject to space, and then feeding that energy back into the thermal loop when conditions are more favorable. Because they do not use an expendable resource, such as the feed water used by sublimators and evaporators, PCM Heat Exchangers are ideal for long duration LLO missions. In order to validate the performance of PCM Heat Exchangers, a life test is being conducted on four n-Pentadecane, carbon filament heat exchangers. Fluid loop performance, repeatability, and measurement of performance degradation over 2500 melt-freeze cycles will be performed.

  14. Phase Change Fabrics Control Temperature

    Science.gov (United States)

    2009-01-01

    Originally featured in Spinoff in 1997, Outlast Technologies Inc. (formerly Gateway Technologies Inc.) has built its entire product line on microencapsulated phase change materials, developed in Small Business Innovation Research (SBIR) contracts with Johnson Space Center after initial development for the U.S. Air Force. The Boulder, Colorado-based company acquired the exclusive patent rights and now integrates these materials into textiles or onto finished apparel, providing temperature regulation in bedding materials and a full line of apparel for both ordinary and extreme conditions.

  15. Laboratory Evaluation of Nitrile Fuel Tank Materials (Phase 2)

    Science.gov (United States)

    2013-09-01

    Laboratory Evaluation of Nitrile Fuel Tank Materials (Phase II) by James M. Sloan, David Flanagan, Daniel DeSchepper, Paul Touchet, and...21005-5066 ARL-TR-6627 September 2013 Laboratory Evaluation of Nitrile Fuel Tank Materials (Phase II) James M. Sloan, David Flanagan, and...COVERED (From - To) October 2011–March 2013 4. TITLE AND SUBTITLE Laboratory Evaluation of Nitrile Fuel Tank Materials (Phase II) 5a. CONTRACT NUMBER

  16. Energy efficiency of buildings with phase-change materials

    Directory of Open Access Journals (Sweden)

    Lukić Predrag

    2012-01-01

    Full Text Available The construction of energy efficient buildings using innovative building materials such as phase change materials, in addition to improving indoor comfort, energy savings and costs, can be achieved by increasing their market value. Because of its ability to absorb and release energy at predictable temperatures, phase change materials are effective in controlling and maintaining the thermal environment in the building. The use of phase changing materials, materials stored latent energy storage is an effective form of heat. [Projekat Ministarstva nauke Republike Srbije, br. TR36016: Experimental and theoretical investigation of frames and plates with semi-rigid connections from the view of the second order theory and stability analysis

  17. PHASE CHANGE MATERIALS IN FLOOR TILES FOR THERMAL ENERGY STORAGE

    Energy Technology Data Exchange (ETDEWEB)

    Douglas C. Hittle

    2002-10-01

    Passive solar systems integrated into residential structures significantly reduce heating energy consumption. Taking advantage of latent heat storage has further increased energy savings. This is accomplished by the incorporation of phase change materials into building materials used in passive applications. Trombe walls, ceilings and floors can all be enhanced with phase change materials. Increasing the thermal storage of floor tile by the addition of encapsulated paraffin wax is the proposed topic of research. Latent heat storage of a phase change material (PCM) is obtained during a change in phase. Typical materials use the latent heat released when the material changes from a liquid to a solid. Paraffin wax and salt hydrates are examples of such materials. Other PCMs that have been recently investigated undergo a phase transition from one solid form to another. During this process they will release heat. These are known as solid-state phase change materials. All have large latent heats, which makes them ideal for passive solar applications. Easy incorporation into various building materials is must for these materials. This proposal will address the advantages and disadvantages of using these materials in floor tile. Prototype tile will be made from a mixture of quartz, binder and phase change material. The thermal and structural properties of the prototype tiles will be tested fully. It is expected that with the addition of the phase change material the structural properties will be compromised to some extent. The ratio of phase change material in the tile will have to be varied to determine the best mixture to provide significant thermal storage, while maintaining structural properties that meet the industry standards for floor tile.

  18. Stress-Induced Phase Transformation in Incompressible Materials and Stability of Multi-Phase Deformation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The stress-induced phase transformation in incompressible materials and the interfacial stability of multi-phase deformation were studied. The existence of multi-phase deformation was determined through exploring whether the material would lose the strong ellipticity at some deformation gradient.Then, according to the stability criterion which is based on a quasi-static approach, the stability of the multi-phase deformation in incompressible materials was investigated by studying the growth/decay behaviour of the interface in the undeformed configuration when it is perturbed. At last, the way to define multi-phase deformation in incompressible materials was concluded and testified by a corresponding numerical example.

  19. A New Kind of Shape-stabilized Phase Change Materials

    Institute of Scientific and Technical Information of China (English)

    XIAO Liguang; DING Rui; SUN Hao; WANG Fujun

    2011-01-01

    Based on the lowest melting point and Schroeder's theoretical calculation formula, nanomodified organic composite phase change materials (PCMs) were prepared. The phase transition temperature and the latent heat of the materials were 24 ℃ and 172 J/g, respectively. A new shape-stabilized phase change materials were prepared, using high density polyethylene as supporting material. The PCM kept the shape when temperature was higher than melting point. Thus, it can directly contact with heat transfer media. The structure,morphology and thermal behavior of PCM were analyzed by FTIR, SEM and DSC.

  20. Phase stress measurements in composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Akiniwa, Yoshiaki; Tanaka, Keisuke [Nagoya Univ. (Japan). School of Engineering

    1997-06-01

    Using an aluminum alloy composite containing 20 wt.% of SiC powder and an aluminum alloy itself, a phase stress under monoaxial tensile load was tested using x-ray and neutron methods, to compare both of them. For specimens, a 20 vol.% SiC powder reinforced aluminum alloy and an aluminum alloy itself were used. As a result, the following results could be obtained. Young`s modulus and Poisson ratio of the aluminum alloy itself using x-ray method were E=74.5 GPa and {nu}=0.312, respectively, and those using neutron method were E=75.3 GPa and {nu}=0.384, respectively. A relationship between loading stress and lattice strain of the aluminum alloy itself using neutron method was possible to approximate linearly by containing macroscopic plastic deformation region. The lattice strain of each phase in the composite increased proportionally with loading stress in its elastic region, but when remarkably increasing plastic deformation, the lattice strain decreased proportionally in aluminum phase and increased in SiC phase. (G.K.)

  1. Nonminimum Phase Behavior of Laser Material Processing

    NARCIS (Netherlands)

    Römer, G.R.B.E.; Weerkamp, N.P.; Meijer, J.; Postma, S.

    2001-01-01

    Optical sensors are increasingly applied in laser material processing to monitor and control the lasermaterial interaction zone. Dynamic models, relating the sensor signals (e.g. as temperature or molten area) to the process inputs (e.g. laser power or beam velocity), provide the basis for the desig

  2. Application of phase-change materials in memory taxonomy.

    Science.gov (United States)

    Wang, Lei; Tu, Liang; Wen, Jing

    2017-01-01

    Phase-change materials are suitable for data storage because they exhibit reversible transitions between crystalline and amorphous states that have distinguishable electrical and optical properties. Consequently, these materials find applications in diverse memory devices ranging from conventional optical discs to emerging nanophotonic devices. Current research efforts are mostly devoted to phase-change random access memory, whereas the applications of phase-change materials in other types of memory devices are rarely reported. Here we review the physical principles of phase-change materials and devices aiming to help researchers understand the concept of phase-change memory. We classify phase-change memory devices into phase-change optical disc, phase-change scanning probe memory, phase-change random access memory, and phase-change nanophotonic device, according to their locations in memory hierarchy. For each device type we discuss the physical principles in conjunction with merits and weakness for data storage applications. We also outline state-of-the-art technologies and future prospects.

  3. Single phase 3D phononic band gap material.

    Science.gov (United States)

    Warmuth, Franziska; Wormser, Maximilian; Körner, Carolin

    2017-06-19

    Phononic band gap materials are capable of prohibiting the propagation of mechanical waves in certain frequency ranges. Band gaps are produced by combining different phases with different properties within one material. In this paper, we present a novel cellular material consisting of only one phase with a phononic band gap. Different phases are modelled by lattice structure design based on eigenmode analysis. Test samples are built from a titanium alloy using selective electron beam melting. For the first time, the predicted phononic band gaps via FEM simulation are experimentally verified. In addition, it is shown how the position and extension of the band gaps can be tuned by utilizing knowledge-based design.

  4. Thin Film Composite Materials, Phase 2

    Science.gov (United States)

    1987-01-01

    were Kevlar coated with silicone, EPDM , or neoprene rubber, with the following results: 1. Tensile testing of coated Kevlar fabric is very difficult...materials. 2. A method was developed for measuring water vapor permeability. Neoprene and EPDM are promising as coatings with good water resistance; however...control the folding of the fabric, since the diameters of the spiral channel will be fixed. Because of the stability imparted by the channel, it is

  5. Confined crystals of the smallest phase-change material.

    Science.gov (United States)

    Giusca, Cristina E; Stolojan, Vlad; Sloan, Jeremy; Börrnert, Felix; Shiozawa, Hidetsugu; Sader, Kasim; Rümmeli, Mark H; Büchner, Bernd; Silva, S Ravi P

    2013-09-11

    The demand for high-density memory in tandem with limitations imposed by the minimum feature size of current storage devices has created a need for new materials that can store information in smaller volumes than currently possible. Successfully employed in commercial optical data storage products, phase-change materials, that can reversibly and rapidly change from an amorphous phase to a crystalline phase when subject to heating or cooling have been identified for the development of the next generation electronic memories. There are limitations to the miniaturization of these devices due to current synthesis and theoretical considerations that place a lower limit of 2 nm on the minimum bit size, below which the material does not transform in the structural phase. We show here that by using carbon nanotubes of less than 2 nm diameter as templates phase-change nanowires confined to their smallest conceivable scale are obtained. Contrary to previous experimental evidence and theoretical expectations, the nanowires are found to crystallize at this scale and display amorphous-to-crystalline phase changes, fulfilling an important prerequisite of a memory element. We show evidence for the smallest phase-change material, extending thus the size limit to explore phase-change memory devices at extreme scales.

  6. Next Generation Advanced Binder Chemistries for High Performance, Environmetally DurableThermal Control Material Systems. Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This innovative SBIR Phase I proposal will develop new binder systems through the systematic investigations to tailor required unique performance properties and...

  7. Perhydroazulene-based liquid-crystalline materials with smectic phases.

    Science.gov (United States)

    Hussain, Zakir; Hopf, Henning; Eichhorn, S Holger

    2012-01-01

    New liquid-crystalline materials with a perhydroazulene core were synthesized and the stereochemistry of these compounds was investigated. The mesomorphic properties of the new LC compounds were investigated by differential scanning colorimetry, polarizing optical microscopy and X-ray diffraction. We report here on the LC properties of nonchiral materials, which predominantly exhibit smectic phases and display nematic phases only within narrow temperature ranges. The dependence of the mesogenic behavior of the new materials on the stereochemistry of the core system was also investigated. All newly synthesized compounds were fully characterized by the usual spectroscopic and analytical methods.

  8. Perhydroazulene-based liquid-crystalline materials with smectic phases

    Directory of Open Access Journals (Sweden)

    Zakir Hussain

    2012-03-01

    Full Text Available New liquid-crystalline materials with a perhydroazulene core were synthesized and the stereochemistry of these compounds was investigated. The mesomorphic properties of the new LC compounds were investigated by differential scanning colorimetry, polarizing optical microscopy and X-ray diffraction. We report here on the LC properties of nonchiral materials, which predominantly exhibit smectic phases and display nematic phases only within narrow temperature ranges. The dependence of the mesogenic behavior of the new materials on the stereochemistry of the core system was also investigated. All newly synthesized compounds were fully characterized by the usual spectroscopic and analytical methods.

  9. SBIR Advanced Technologies in Aviation and Air Transportation System 2016

    Science.gov (United States)

    Nguyen, Hung D.; Steele, Gynelle C.; Kaszeta, Richard W.; Gold, Calman; Corke, Thomas C.; McGowan, Ryan; Matlis, Eric; Eichenlaub, Jesse; Davis, Joshua T.; Shah, Parthiv N.

    2017-01-01

    This report is intended to provide a broad knowledge of various topics associated with NASA's Aeronautics Research Mission Directorate (ARMD), with particular interest on the NASA SBIR contracts awarded from 2011-2012 executed by small companies. The content of this report focuses on the high-quality, cutting-edge research that will lead to revolutionary concepts, technologies, and capabilities that enable radical change to both the airspace system and the aircraft that fly within it, facilitating a safer, more environmentally friendly, and more efficient air transportation system.

  10. 48 CFR 227.7104 - Contracts under the Small Business Innovation Research (SBIR) Program.

    Science.gov (United States)

    2010-10-01

    ... Business Innovation Research (SBIR) Program. 227.7104 Section 227.7104 Federal Acquisition Regulations... Data and Computer Software—Small Business Innovation Research (SBIR) Program, when technical data or... PATENTS, DATA, AND COPYRIGHTS Rights in Technical Data 227.7104 Contracts under the Small...

  11. 77 FR 30227 - Small Business Size Regulations, Small Business Innovation Research (SBIR) Program and Small...

    Science.gov (United States)

    2012-05-22

    ... (SBIR) Program and Small Business Technology Transfer (STTR) Program AGENCY: U.S. Small Business... (SBIR) and Small Business Technology Transfer (STTR) Programs. The proposed rule would implement... technological constraints, participation is limited to 125 registrants for the Webinar. If demand...

  12. Modeling the Reactions of Energetic Materials in the Condensed Phase

    Energy Technology Data Exchange (ETDEWEB)

    Fried, L E; Manaa, M R; Lewis, J P

    2003-12-03

    High explosive (HE) materials are unique for having a strong exothermic reactivity, which has made them desirable for both military and commercial applications. Although the history of HE materials is long, condensed-phase properties are poorly understood. Understanding the condensed-phase properties of HE materials is important for determining stability and performance. Information regarding HE material properties (for example, the physical, chemical, and mechanical behaviors of the constituents in plastic-bonded explosive, or PBX, formulations) is necessary in efficiently building the next generation of explosives as the quest for more powerful energetic materials (in terms of energy per volume) moves forward. In addition, understanding the reaction mechanisms has important ramifications in disposing of such materials safely and cheaply, as there exist vast stockpiles of HE materials with corresponding contamination of earth and groundwater at these sites, as well as a military testing sites The ability to model chemical reaction processes in condensed phase energetic materials is rapidly progressing. Chemical equilibrium modeling is a mature technique with some limitations. Progress in this area continues, but is hampered by a lack of knowledge of condensed phase reaction mechanisms and rates. Atomistic modeling is much more computationally intensive, and is currently limited to very short time scales. Nonetheless, this methodology promises to yield the first reliable insights into the condensed phase processes responsible for high explosive detonation. Further work is necessary to extend the timescales involved in atomistic simulations. Recent work in implementing thermostat methods appropriate to shocks may promise to overcome some of these difficulties. Most current work on energetic material reactivity assumes that electronically adiabatic processes dominate. The role of excited states is becoming clearer, however. These states are not accessible in perfect

  13. Unconventional phase field simulations of transforming materials with evolving microstructures

    Institute of Scientific and Technical Information of China (English)

    Jiang-Yu Li; Chi-Hou Lei; Liang-Jun Li; Yi-Chung Shu; Yun-Ya Liu

    2012-01-01

    Transforming materials with evolving microstructures is one of the most important classes of smart materials that have many potential technological applications,and an unconventional phase field approach based on the characteristic functions of transforming variants has been developed to simulate the formation and evolution of their microstructures.This approach is advantageous in its explicit material symmetry and energy well structure,minimal number of material coefficients,and easiness in coupling multiple physical processes and order parameters,and has been applied successfully to study the microstructures and macroscopic properties of shape memory alloys,ferroelectrics,ferromagnetic shape memory alloys,and multiferroic magnetoelectric crystals and films with increased complexity.In this topical review,the formulation of this unconventional phase field approach will be introduced in details,and its applications to various transforming materials will be discussed.Some examples of specific microstructures will also be presented.

  14. Thermodynamics and Kinetics of Phase Transformations in Hydrogen Storage Materials

    Energy Technology Data Exchange (ETDEWEB)

    Ceder, Gerbrand; Marzari, Nicola

    2011-08-31

    The aim of this project is to develop and apply computational materials science tools to determine and predict critical properties of hydrogen storage materials. By better understanding the absorption/desorption mechanisms and characterizing their physical properties it is possible to explore and evaluate new directions for hydrogen storage materials. Particular emphasis is on the determination of the structure and thermodynamics of hydrogen storage materials, the investigation of microscopic mechanisms of hydrogen uptake and release in various materials and the role of catalysts in this process. As a team we have decided to focus on a single material, NaAlH{sub 4}, in order to fully be able to study the many aspects of hydrogen storage. We have focused on phase stability, mass transport and size-dependent reaction mechanisms in this material.

  15. Thermal energy storage using phase change materials fundamentals and applications

    CERN Document Server

    Fleischer, Amy S

    2015-01-01

    This book presents a comprehensive introduction to the use of solid‐liquid phase change materials to store significant amounts of energy in the latent heat of fusion. The proper selection of materials for different applications is covered in detail, as is the use of high conductivity additives to enhance thermal diffusivity. Dr. Fleischer explores how applications of PCMS have expanded over the past 10 years to include the development of high efficiency building materials to reduce heating and cooling needs, smart material design for clothing, portable electronic systems thermal management, solar thermal power plant design and many others. Additional future research directions and challenges are also discussed.

  16. LIGHT-WEIGHT NANOCRYSTALLINE HYDROGEN STORAGE MATERIALS

    Energy Technology Data Exchange (ETDEWEB)

    S. G. Sankar; B. Zande; R.T. Obermyer; S. Simizu

    2005-11-21

    During Phase I of this SBIR Program, Advanced Materials Corporation has addressed two key issues concerning hydrogen storage: 1. We have conducted preliminary studies on the effect of certain catalysts in modifying the hydrogen absorption characteristics of nanocrystalline magnesium. 2. We have also conducted proof-of-concept design and construction of a prototype instrument that would rapidly screen materials for hydrogen storage employing chemical combinatorial technique in combination with a Pressure-Composition Isotherm Measurement (PCI) instrument. 3. Preliminary results obtained in this study approach are described in this report.

  17. Multilayer Pressure Vessel Materials Testing and Analysis. Phase 1

    Science.gov (United States)

    Cardinal, Joseph W.; Popelar, Carl F.; Page, Richard A.

    2014-01-01

    To provide NASA a comprehensive suite of materials strength, fracture toughness and crack growth rate test results for use in remaining life calculations for aging multilayer pressure vessels, Southwest Research Institute (R) (SwRI) was contracted in two phases to obtain relevant material property data from a representative vessel. This report describes Phase 1 of this effort which includes a preliminary material property assessment as well as a fractographic, fracture mechanics and fatigue crack growth analyses of an induced flaw in the outer shell of a representative multilayer vessel that was subjected to cyclic pressure test. SwRI performed this Phase 1 effort under contract to the Digital Wave Corporation in support of their contract to Jacobs ATOM for the NASA Ames Research Center.

  18. Counterposition and negative phase velocity in uniformly moving dissipative materials

    Energy Technology Data Exchange (ETDEWEB)

    Mackay, Tom G [School of Mathematics and Maxwell Institute for Mathematical Sciences, University of Edinburgh, Edinburgh EH9 3JZ (United Kingdom); Lakhtakia, Akhlesh [NanoMM-Nanoengineered Metamaterials Group, Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802-6812 (United States)], E-mail: T.Mackay@ed.ac.uk, E-mail: akhlesh@psu.edu

    2009-10-16

    We considered the phenomena of counterposition and negative phase velocity, which are relevant to certain metamaterials and certain astrophysical scenarios. The Lorentz transformations of electric and magnetic fields were implemented to study (i) the refraction of linearly polarized plane waves into a half-space occupied by a uniformly moving material and (ii) the traversal of linearly polarized Gaussian beams through a uniformly moving slab. Motion was taken to occur tangentially to the interface(s) and in the plane of incidence. The moving materials were assumed to be isotropic, homogeneous and dissipative dielectric materials from the perspective of a co-moving observer. Two different moving materials were considered: from the perspective of a co-moving observer, material A supports planewave propagation with only positive phase velocity, whereas material B supports planewave propagation with both positive and negative phase velocity, depending on the polarization state. For both materials A and B, the sense of the phase velocity and whether or not counterposition occurred, as perceived by a non-co-moving observer, could be altered by varying the observer's velocity. Furthermore, the lateral position of a beam upon propagating through a uniformly moving slab made of material A, as perceived by a non-co-moving observer, could be controlled by varying the observer's velocity. In particular, at certain velocities, the transmitted beam emerged from the slab laterally displaced in the direction opposite to the direction of incident beam. The transmittances of a uniformly moving slab made of material B were very small and the energy density of the transmitted beam was largely concentrated in the direction normal to the slab, regardless of the observer's velocity.

  19. Thermal Performance of Microencapsulated Phase Change Material Survey

    Science.gov (United States)

    2008-03-01

    ER D C TR -0 8 -4 Basic Research/Military Construction Thermal Performance of Microencapsulated Phase Change Material Slurry Jorge L...distribution is unlimited. Basic Research/Military Construction ERDC TR-08-4 March 2008 Thermal Performance of Microencapsulated Phase Change... microencapsulated PCM (MPCM) slurries is enhanced significantly, even when using low volume fractions. MPCM slurries have potential to decrease costs and improve

  20. Thermal Performance of Microencapsulated Phase Change Material Slurry

    Science.gov (United States)

    2008-03-01

    ER D C TR -0 8 -4 Basic Research/Military Construction Thermal Performance of Microencapsulated Phase Change Material Slurry Jorge L...distribution is unlimited. Basic Research/Military Construction ERDC TR-08-4 March 2008 Thermal Performance of Microencapsulated Phase Change... microencapsulated PCM (MPCM) slurries is enhanced significantly, even when using low volume fractions. MPCM slurries have potential to decrease costs and improve

  1. Subthreshold electrical transport in amorphous phase-change materials

    Science.gov (United States)

    Le Gallo, Manuel; Kaes, Matthias; Sebastian, Abu; Krebs, Daniel

    2015-09-01

    Chalcogenide-based phase-change materials play a prominent role in information technology. In spite of decades of research, the details of electrical transport in these materials are still debated. In this article, we present a unified model based on multiple-trapping transport together with 3D Poole-Frenkel emission from a two-center Coulomb potential. With this model, we are able to explain electrical transport both in as-deposited phase-change material thin films, similar to experimental conditions in early work dating back to the 1970s, and in melt-quenched phase-change materials in nanometer-scale phase-change memory devices typically used in recent studies. Experimental measurements on two widely different device platforms show remarkable agreement with the proposed mechanism over a wide range of temperatures and electric fields. In addition, the proposed model is able to seamlessly capture the temporal evolution of the transport properties of the melt-quenched phase upon structural relaxation.

  2. Lightweight Phase-Change Material For Solar Power

    Science.gov (United States)

    Stark, Philip

    1993-01-01

    Lightweight panels containing phase-change materials developed for use as heat-storage elements of compact, lightweight, advanced solar dynamic power system. During high insolation, heat stored in panels via latent heat of fusion of phase-change material; during low insolation, heat withdrawn from panels. Storage elements consist mainly of porous carbon-fiber structures imbued with germanium. Developed for use aboard space station in orbit around Earth, also adapted to lightweight, compact, portable solar-power systems for use on Earth.

  3. Recent Advances on Neuromorphic Systems Using Phase-Change Materials

    Science.gov (United States)

    Wang, Lei; Lu, Shu-Ren; Wen, Jing

    2017-05-01

    Realization of brain-like computer has always been human's ultimate dream. Today, the possibility of having this dream come true has been significantly boosted due to the advent of several emerging non-volatile memory devices. Within these innovative technologies, phase-change memory device has been commonly regarded as the most promising candidate to imitate the biological brain, owing to its excellent scalability, fast switching speed, and low energy consumption. In this context, a detailed review concerning the physical principles of the neuromorphic circuit using phase-change materials as well as a comprehensive introduction of the currently available phase-change neuromorphic prototypes becomes imperative for scientists to continuously progress the technology of artificial neural networks. In this paper, we first present the biological mechanism of human brain, followed by a brief discussion about physical properties of phase-change materials that recently receive a widespread application on non-volatile memory field. We then survey recent research on different types of neuromorphic circuits using phase-change materials in terms of their respective geometrical architecture and physical schemes to reproduce the biological events of human brain, in particular for spike-time-dependent plasticity. The relevant virtues and limitations of these devices are also evaluated. Finally, the future prospect of the neuromorphic circuit based on phase-change technologies is envisioned.

  4. Optimization of a phase change material wallboard for building use

    Energy Technology Data Exchange (ETDEWEB)

    Kuznik, Frederic; Virgone, Joseph [Thermal Sciences Center of Lyon, CNRS, UMR 5008, INSA de Lyon, Universite Lyon 1, Bat Freyssinet, 40 Rue des Arts, 69621 Villeurbanne Cedex (France); Noel, Jean [Free-lance Scientific Software Developer, 15 Place Carnot, 69002 Lyon (France)

    2008-08-15

    In construction, the use of phase change materials (PCM) allows the storage/release of energy from the solar radiation and/or internal loads. The application of such materials for lightweight construction (e.g., a wood house) makes it possible to improve thermal comfort and reduce energy consumption. A wallboard composed of a new PCM material is investigated in this paper to enhance the thermal behavior of a lightweight internal partition wall. The paper focuses on the optimization of phase change material thickness. The in-house software CODYMUR is used to optimize the PCM wallboard by the means of numerical simulations. The results show that an optimal PCM thickness exists. The optimal PCM thickness value is then calculated for use in construction. (author)

  5. Temperature reduction due to the application of phase change materials

    Energy Technology Data Exchange (ETDEWEB)

    Voelker, Conrad; Kornadt, Oliver [Department of Building Physics, Bauhaus-University Weimar, Coudraystrasse 11a, 99423 Weimar (Germany); Ostry, Milan [Faculty of Civil Engineering, Brno University of Technology, Department of Building Structures, Veveri 95, 602 00 Brno (Czech Republic)

    2008-07-01

    Overheating is a major problem in many modern buildings due to the utilization of lightweight constructions with low heat storing capacity. A possible answer to this problem is the emplacement of phase change materials (PCM), thereby increasing the thermal mass of a building. These materials change their state of aggregation within a defined temperature range. Useful PCM for buildings show a phase transition from solid to liquid and vice versa. The thermal mass of the materials is increased by the latent heat. A modified gypsum plaster and a salt mixture were chosen as two materials for the study of their impact on room temperature reduction. For realistic investigations, test rooms were erected where measurements were carried out under different conditions such as temporary air change, alternate internal heat gains or clouding. The experimental data was finally reproduced by dint of a mathematical model. (author)

  6. A Gibbs Formulation for Reactive Materials with Phase Change

    Science.gov (United States)

    Stewart, D. Scott

    2015-11-01

    A large class of applications have pure, condensed phase constituents that come into contact, chemically react and simultaneously undergo phase change. Phase change in a given molecular material has often been considered to be separate from chemical reaction. Continuum modelers of phase change often use a phase field model whereby an indicator function is allowed to change from one value to another in regions of phase change, governed by evolutionary (Ginzburg-Landau) equations, whereas classic chemical kinetics literally count species concentrations and derive kinetics evolution equations based on species mass transport. We argue the latter is fundamental and is the same as the former, if all species, phase or chemical are treated as distinct chemical species. We pose a self-consistent continuum, thermo-mechanical model to account for significant energetic quantities with correct molecular and continuum limits in the mixture. A single stress tensor, and a single temperature is assumed for the mixture with specified Gibbs potentials for all relevant species, and interaction energies. We discuss recent examples of complex reactive material modeling, drawn from thermitic and propellant combustion that use this new model. DSS supported by DTRA, ONR and AFOSR.

  7. Phase change materials and the perception of wetness

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Kosters, N.D.; Kappers, A.M.L.; Daanen, H.A.M.

    2012-01-01

    Phase change materials (PCMs) are increasingly incorporated in textiles in order to serve as a thermal buffer when humans change from a hot to a cold environment and the reverse. Due to the absence of wetness sensors in the skin, cooling of the skin may be perceived as a sensation of wetness instead

  8. Preparation of Firefighting Hood for Cooling for Phase Change Materials

    Directory of Open Access Journals (Sweden)

    Shu Hwa Lin

    2016-10-01

    Full Text Available There are two types of Phase Change Materials (PCMs which have been developed and adopted in textiles: heat (energy released and cool (energy absorbed. This paper discusses current PCM applications and explores future applications in firefighting gear. Phase change materials are considered latent heat storage units because as they change phase from solid to liquid, liquid to gas and vice versa, energy in the form of heat is absorbed or released. The goal of PCM textiles is to create reusable energy to maintain body temperature, as well as to optimize the performance of protective wear such as hoods. When the wearer’s body temperature increases or decreases, the PCMs applied to the fabric will change state helping to regulate the wearer’s body temperature by providing warmth or cooling. Maintaining a stable body temperature can improve working conditions and comfort.

  9. Preparation of Firefighting Hood for Cooling For Phase Change Materials

    Directory of Open Access Journals (Sweden)

    Shu Hwa Lin

    2016-10-01

    Full Text Available There are two types of Phase Change Materials (PCMs which have been developed and adopted in textiles: heat (energy released and cool (energy absorbed. This paper discusses current PCM applications and explores future applications in firefighting gear. Phase change materials are considered latent heat storage units because as they change phase from solid to liquid, liquid to gas and vice versa, energy in the form of heat is absorbed or released. The goal of PCM textiles is to create reusable energy to maintain body temperature, as well as to optimize the performance of protective wear such as hoods. When the wearer’s body temperature increases or decreases, the PCMs applied to the fabric will change state helping to regulate the wearer’s body temperature by providing warmth or cooling. Maintaining a stable body temperature can improve working conditions and comfort.

  10. A single-component liquid-phase hydrogen storage material.

    Science.gov (United States)

    Luo, Wei; Campbell, Patrick G; Zakharov, Lev N; Liu, Shih-Yuan

    2011-12-07

    The current state-of-the-art for hydrogen storage is compressed H(2) at 700 bar. The development of a liquid-phase hydrogen storage material has the potential to take advantage of the existing liquid-based distribution infrastructure. We describe a liquid-phase hydrogen storage material that is a liquid under ambient conditions (i.e., at 20 °C and 1 atm pressure), air- and moisture-stable, and recyclable; releases H(2) controllably and cleanly at temperatures below or at the proton exchange membrane fuel cell waste-heat temperature of 80 °C; utilizes catalysts that are cheap and abundant for H(2) desorption; features reasonable gravimetric and volumetric storage capacity; and does not undergo a phase change upon H(2) desorption. © 2011 American Chemical Society

  11. Ultrafast response of phase-change memory materials

    Science.gov (United States)

    Lindenberg, Aaron

    2015-03-01

    We describe recent experiments probing the first steps in the amorphous-to-crystalline transition that underlies the behavior of phase-change materials, examining both electric-field-driven and optically-driven responses in GeSbTe and AgInSbTe alloys. First measurements using femtosecond x-ray pulses at the Linac Coherent Light Source will be described which enable direct snapshots of these transitions and associated intermediate states. We will also describe studies using single-cycle terahertz pulses as an all-optical means of biasing phase-change materials on femtosecond time-scales in order to examine the threshold-switching response on microscopically relevant time-scales. These studies indicate nonlinear scaling with the applied electric field and field-induced crystallization as evidenced by ultrafast optical reflectivity and conductivity measurements, from which a mechanistic understanding of these phase transitions can be obtained.

  12. Development of Latent Heat Storage Phase Change Material Containing Plaster

    Directory of Open Access Journals (Sweden)

    Diana BAJARE

    2016-05-01

    Full Text Available This paper reviews the development of latent heat storage Phase Change Material (PCM containing plaster as in passive application. Due to the phase change, these materials can store higher amounts of thermal energy than traditional building materials and can be used to add thermal inertia to lightweight constructions. It was shown that the use of PCMs have advantages stabilizing the room temperature variations during summer days, provided sufficient night ventilation is allowed. Another advantage of PCM usage is stabilized indoor temperature on the heating season. The goal of this study is to develop cement and lime based plaster containing microencapsulated PCM. The plaster is expected to be used for passive indoor applications and enhance the thermal properties of building envelope. The plaster was investigated under Scanning Electron Microscope and the mechanical, physical and thermal properties of created plaster samples were determined.

  13. Development of Latent Heat Storage Phase Change Material Containing Plaster

    Directory of Open Access Journals (Sweden)

    Diana BAJARE

    2016-05-01

    Full Text Available This paper reviews the development of latent heat storage Phase Change Material (PCM containing plaster as in passive application. Due to the phase change, these materials can store higher amounts of thermal energy than traditional building materials and can be used to add thermal inertia to lightweight constructions. It was shown that the use of PCMs have advantages stabilizing the room temperature variations during summer days, provided sufficient night ventilation is allowed. Another advantage of PCM usage is stabilized indoor temperature on the heating season. The goal of this study is to develop cement and lime based plaster containing microencapsulated PCM. The plaster is expected to be used for passive indoor applications and enhance the thermal properties of building envelope. The plaster was investigated under Scanning Electron Microscope and the mechanical, physical and thermal properties of created plaster samples were determined.

  14. Round-Robin Test of Paraffin Phase-Change Material

    Science.gov (United States)

    Vidi, S.; Mehling, H.; Hemberger, F.; Haussmann, Th.; Laube, A.

    2015-11-01

    A round-robin test between three institutes was performed on a paraffin phase-change material (PCM) in the context of the German quality association for phase-change materials. The aim of the quality association is to define quality and test specifications for PCMs and to award certificates for successfully tested materials. To ensure the reproducibility and comparability of the measurements performed at different institutes using different measuring methods, a round-robin test was performed. The sample was unknown. The four methods used by the three participating institutes in the round-robin test were differential scanning calorimetry, Calvet calorimetry and three-layer calorimetry. Additionally, T-history measurements were made. The aim of the measurements was the determination of the enthalpy as a function of temperature. The results achieved following defined test specifications are in excellent agreement.

  15. Piezoelectric properties of rhombohedral ferroelectric materials with phase transition

    Science.gov (United States)

    Zhao, Xiaofang; Soh, A. K.

    2015-12-01

    The temporal evolution of domain structure and its piezoelectric behavior of ferroelectric material BaTiO3 during the transition process from rhombohedral to tetragonal phase under an applied electric field have been studied by employing Landau-Ginzburg theory and the phase-field method. The results obtained show that, during the transformation process, the intermediate phase was monoclinic MA phase, and several peak values of piezoelectric coefficient appeared at the stage where obvious change of domain pattern occurred. In addition, by comparing the cases of applied electric field with different frequencies, it was found that the maximum piezoelectric coefficient obtained decreased with increasing frequency value. These results are of great significance in tuning the properties of engineering domains in ferroelectrics, and could provide more fundamentals to the design of ferroelectric devices.

  16. Vibration damping and heat transfer using material phase changes

    Science.gov (United States)

    Kloucek, Petr (Inventor); Reynolds, Daniel R. (Inventor)

    2009-01-01

    A method and apparatus wherein phase changes in a material can dampen vibrational energy, dampen noise and facilitate heat transfer. One embodiment includes a method for damping vibrational energy in a body. The method comprises attaching a material to the body, wherein the material comprises a substrate, a shape memory alloy layer, and a plurality of temperature change elements. The method further comprises sensing vibrations in the body. In addition, the method comprises indicating to at least a portion of the temperature change elements to provide a temperature change in the shape memory alloy layer, wherein the temperature change is sufficient to provide a phase change in at least a portion of the shape memory alloy layer, and further wherein the phase change consumes a sufficient amount of kinetic energy to dampen at least a portion of the vibrational energy in the body. In other embodiments, the shape memory alloy layer is a thin film. Additional embodiments include a sensor connected to the material.

  17. Investigating materials formation with liquid-phase and cryogenic TEM

    Science.gov (United States)

    de Yoreo, J. J.; N. A. J. M., Sommerdijk

    2016-08-01

    The recent advent of liquid-phase transmission electron microscopy (TEM) and advances in cryogenic TEM are transforming our understanding of the physical and chemical mechanisms underlying the formation of materials in synthetic, biological and geochemical systems. These techniques have been applied to study the dynamic processes of nucleation, self-assembly, crystal growth and coarsening for metallic and semiconductor nanoparticles, (bio)minerals, electrochemical systems, macromolecular complexes, and organic and inorganic self-assembling systems. New instrumentation and methodologies that are currently on the horizon promise new opportunities for advancing the science of materials synthesis.

  18. Kinetic Processes Crystal Growth, Diffusion, and Phase Transformations in Materials

    CERN Document Server

    Jackson, Kenneth A

    2004-01-01

    The formation of solids is governed by kinetic processes, which are closely related to the macroscopic behaviour of the resulting materials. With the main focus on ease of understanding, the author begins with the basic processes at the atomic level to illustrate their connections to material properties. Diffusion processes during crystal growth and phase transformations are examined in detail. Since the underlying mathematics are very complex, approximation methods typically used in practice are the prime choice of approach. Apart from metals and alloys, the book places special emphasis on th

  19. Defense Small Business Innovation Research Program (SBIR). Volume 2. Navy Abstracts of Phase 1 Awards from FY 1988 SBIR Solicitation.

    Science.gov (United States)

    1989-05-01

    RELATIVELY INEXPENSIVE, AND EASY TO APPLY. CENTRA TECHNOLOGY INC 3204 MONROE ST - STE 300 ROCKVILLE, MD 20852 CONTRACT NUMBER: ROBERT E BLASE TITLE: MULTIPATH...RESEARCH CORP 625 EAST ST FAIRPORT HARBOR, OH 44077 CONTRACT NUMBER: MARILYN J NIKSA TITLE: THE ALUMINUM/AIR FUEL CELL: AN ADVANCED POWER SOURCE FOR

  20. The role of phase change materials for the sustainable energy

    Directory of Open Access Journals (Sweden)

    Kuta Marta

    2016-01-01

    Full Text Available Unceasing global economic development leads to continuous increase of energy demand. Considering the limited conventional resources of energy as well as impact on the environment associated with its use, it is important to focus on the rational management of energy resources and on supporting the development of new technologies related to both conventional and renewable energy resources. In a number of cases the use of phase change materials (PCMs turns out to be a reasonable solution. This paper contains a summary of well-studied and known, previously used solutions based on phase change materials as well as novel possibilities, which are under development. It has been decided to investigate this topic due to the wide range of highly effective solutions. The review is focused on selected applications of PCMs for technologies which are designed to improve energy efficiency and on PCMs used in technologies based on renewable energy sources.

  1. Effect of phase transformations on microstructures in deep mantle materials

    Science.gov (United States)

    Merkel, Sébastien; Langrand, Christopher; Rosa, Angelika; Hilairet, Nadège

    2017-04-01

    Phase transformations induce microstructural changes in deep Earth materials, including changes in grain size and orientation distribution. The effect of phase transformations on mineral microstructures is usually studied using electron microscopy on quench products from high P/T experiments. The method allows for a precise evaluation of the microscopic mechanisms involved. It is limited, however, to samples that can be quenched to ambient conditions and allows for investigations at a single P/T point for each experiment. In recent years, we extended the use of multigrain crystallography to samples inside diamond anvil cells under mantle P/T conditions. The method allows for monitoring the orientations of hundreds of grains and grain size variations during various physical processes, such as plastic deformation and successions of phase transformations (Rosa et al 2015, Langrand et al 2017). Here, we will show results concerning hydrous Mg2SiO4 during the series of α-β-γ phase transformations up to 40 GPa and 850 °C. Such results are important to understand the descending behaviour of subducted slabs, observations of seismic anisotropy, and polarity changes for seismic waves reflected of deep Earth interfaces. The data is used to asses the effect of the transformation on grain orientation and grain sizes. In particular, we do not observe orientation relationships between the parent α-phase and the daughter β-phase phase, suggesting an incoherent growth. We also observe significant grain size reductions and only little grain growth within the newly formed phases (Rosa et al 2016). These new results are important for understanding the mechanical behavior of subducting slabs, seismic anisotropy in the Earth's mantle, and phase transformation mechanisms in olivine. Now that it is validated, the method can also be applied to other phases that can not be studied using electron microscopy, such as perovskite and post-perovskite. Langrand, Hilairet, Nisr, Roskosz, Rib

  2. A phenomenological approach of solidification of polymeric phase change materials

    Science.gov (United States)

    Bahrani, Seyed Amir; Royon, Laurent; Abou, Bérengère; Osipian, Rémy; Azzouz, Kamel; Bontemps, André

    2017-01-01

    Phase Change Materials (PCMs) are widely used in thermal energy storage and thermal management systems due to their small volume for a given stored energy and their capability for maintaining nearly constant temperatures. However, their performance is limited by their low thermal conductivity and possible leaks while in the liquid phase. One solution is to imprison the PCM inside a polymer mesh to create a Polymeric Phase Change Material (PPCM). In this work, we have studied the cooling and solidification of five PPCMs with different PCMs and polymer fractions. To understand the heat transfer mechanisms involved, we have carried out micro- and macrorheological measurements in which Brownian motion of tracers embedded in PPCMs has been depicted and viscoelastic moduli have been measured, respectively. Beyond a given polymer concentration, it was shown that the Brownian motion of the tracers is limited by the polymeric chains and that the material exhibits an elastic behavior. This would suggest that heat transfer essentially occurs by conduction, instead of convection. Experiments were conducted to measure temperature variation during cooling of the five samples, and a semi-empirical model based on a phenomenological approach was proposed as a practical tool to choose and size PPCMs.

  3. Diffraction phase microscopy: monitoring nanoscale dynamics in materials science [invited].

    Science.gov (United States)

    Edwards, Chris; Zhou, Renjie; Hwang, Suk-Won; McKeown, Steven J; Wang, Kaiyuan; Bhaduri, Basanta; Ganti, Raman; Yunker, Peter J; Yodh, Arjun G; Rogers, John A; Goddard, Lynford L; Popescu, Gabriel

    2014-09-20

    Quantitative phase imaging (QPI) utilizes the fact that the phase of an imaging field is much more sensitive than its amplitude. As fields from the source interact with the specimen, local variations in the phase front are produced, which provide structural information about the sample and can be used to reconstruct its topography with nanometer accuracy. QPI techniques do not require staining or coating of the specimen and are therefore nondestructive. Diffraction phase microscopy (DPM) combines many of the best attributes of current QPI methods; its compact configuration uses a common-path off-axis geometry which realizes the benefits of both low noise and single-shot imaging. This unique collection of features enables the DPM system to monitor, at the nanoscale, a wide variety of phenomena in their natural environments. Over the past decade, QPI techniques have become ubiquitous in biological studies and a recent effort has been made to extend QPI to materials science applications. We briefly review several recent studies which include real-time monitoring of wet etching, photochemical etching, surface wetting and evaporation, dissolution of biodegradable electronic materials, and the expansion and deformation of thin-films. We also discuss recent advances in semiconductor wafer defect detection using QPI.

  4. Scalability of Phase Change Materials in Nanostructure Template

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2015-01-01

    Full Text Available The scalability of In2Se3, one of the phase change materials, is investigated. By depositing the material onto a nanopatterned substrate, individual In2Se3 nanoclusters are confined in the nanosize pits with well-defined shape and dimension permitting the systematic study of the ultimate scaling limit of its use as a phase change memory element. In2Se3 of progressively smaller volume is heated inside a transmission electron microscope operating in diffraction mode. The volume at which the amorphous-crystalline transition can no longer be observed is taken as the ultimate scaling limit, which is approximately 5 nm3 for In2Se3. The physics for the existence of scaling limit is discussed. Using phase change memory elements in memory hierarchy is believed to reduce its energy consumption because they consume zero leakage power in memory cells. Therefore, the phase change memory applications are of great importance in terms of energy saving.

  5. Phase stability in nanoscale material systems: extension from bulk phase diagrams.

    Science.gov (United States)

    Bajaj, Saurabh; Haverty, Michael G; Arróyave, Raymundo; Goddard, William A; Shankar, Sadasivan

    2015-06-07

    Phase diagrams of multi-component systems are critical for the development and engineering of material alloys for all technological applications. At nano dimensions, surfaces (and interfaces) play a significant role in changing equilibrium thermodynamics and phase stability. In this work, it is shown that these surfaces at small dimensions affect the relative equilibrium thermodynamics of the different phases. The CALPHAD approach for material surfaces (also termed "nano-CALPHAD") is employed to investigate these changes in three binary systems by calculating their phase diagrams at nano dimensions and comparing them with their bulk counterparts. The surface energy contribution, which is the dominant factor in causing these changes, is evaluated using the spherical particle approximation. It is first validated with the Au-Si system for which experimental data on phase stability of spherical nano-sized particles is available, and then extended to calculate phase diagrams of similarly sized particles of Ge-Si and Al-Cu. Additionally, the surface energies of the associated compounds are calculated using DFT, and integrated into the thermodynamic model of the respective binary systems. In this work we found changes in miscibilities, reaction compositions of about 5 at%, and solubility temperatures ranging from 100-200 K for particles of sizes 5 nm, indicating the importance of phase equilibrium analysis at nano dimensions.

  6. Small Business Innovation Research, Post-Phase II Opportunity Assessment

    Science.gov (United States)

    Nguyen, Hung D.; Steele, Gynelle C.

    2015-01-01

    This report outlines current Small Business Innovation Research (SBIR) Post-Phase II opportunity contract award results for the SBIR technology program from 2007 to 2011 for NASA's Aeronautics Research Mission Directorate (ARMD), Human Exploration and Operations Mission Directorate (HEOMD), Science Mission Directorate (SMD), and Space Technology Mission Directorate (STMD). The report provides guidelines for incorporating SBIR technology into NASA programs and projects and provides a quantitative overview of the post-Phase II award patterns that correspond with each mission directorate at NASA Glenn Research Center (GRC). In recent years, one of NASA's goals has been to not only transfer SBIR technologies to commercial industries, but to ensure that NASA mission directorates incorporate SBIR technologies into their program and project activities. Before incorporating technologies into MD programs, it is important to understand each mission directorate structure because each directorate has different objectives and needs. The directorate program structures follow.

  7. Phase change thermal control materials, method and apparatus

    Science.gov (United States)

    Buckley, Theresa M. (Inventor)

    2001-01-01

    An apparatus and method for metabolic cooling and insulation of a user in a cold environment. In its preferred embodiment the apparatus is a highly flexible composite material having a flexible matrix containing a phase change thermal storage material. The apparatus can be made to heat or cool the body or to act as a thermal buffer to protect the wearer from changing environmental conditions. The apparatus may also include an external thermal insulation layer and/or an internal thermal control layer to regulate the rate of heat exchange between the composite and the skin of the wearer. Other embodiments of the apparatus also provide 1) a path for evaporation or direct absorption of perspiration from the skin of the wearer for improved comfort and thermal control, 2) heat conductive pathways within the material for thermal equalization, 3) surface treatments for improved absorption or rejection of heat by the material, and 4) means for quickly regenerating the thermal storage capacity for reuse of the material. Applications of the composite materials are also described which take advantage of the composite's thermal characteristics. The examples described include a diver's wet suit, ski boot liners, thermal socks, gloves and a face mask for cold weather activities, and a metabolic heating or cooling blanket useful for treating hypothermia or fever patients in a medical setting and therapeutic heating or cooling orthopedic joint supports.

  8. Ultrafast characterization of phase-change material crystallization properties in the melt-quenched amorphous phase.

    Science.gov (United States)

    Jeyasingh, Rakesh; Fong, Scott W; Lee, Jaeho; Li, Zijian; Chang, Kuo-Wei; Mantegazza, Davide; Asheghi, Mehdi; Goodson, Kenneth E; Wong, H-S Philip

    2014-06-11

    Phase change materials are widely considered for application in nonvolatile memories because of their ability to achieve phase transformation in the nanosecond time scale. However, the knowledge of fast crystallization dynamics in these materials is limited because of the lack of fast and accurate temperature control methods. In this work, we have developed an experimental methodology that enables ultrafast characterization of phase-change dynamics on a more technologically relevant melt-quenched amorphous phase using practical device structures. We have extracted the crystallization growth velocity (U) in a functional capped phase change memory (PCM) device over 8 orders of magnitude (10(-10) programmed PCM devices at very high heating rates (>10(8) K/s), which reveals the extreme fragility of Ge2Sb2Te5 in its supercooled liquid phase. Furthermore, these crystallization properties were studied as a function of device programming cycles, and the results show degradation in the cell retention properties due to elemental segregation. The above experiments are enabled by the use of an on-chip fast heater and thermometer called as microthermal stage (MTS) integrated with a vertical phase change memory (PCM) cell. The temperature at the PCM layer can be controlled up to 600 K using MTS and with a thermal time constant of 800 ns, leading to heating rates ∼10(8) K/s that are close to the typical device operating conditions during PCM programming. The MTS allows us to independently control the electrical and thermal aspects of phase transformation (inseparable in a conventional PCM cell) and extract the temperature dependence of key material properties in real PCM devices.

  9. Phase classification by mean shift clustering of multispectral materials images.

    Science.gov (United States)

    Martins, Diego Schmaedech; Josa, Victor M Galván; Castellano, Gustavo; da Costa, José A T Borges

    2013-10-01

    A mean-shift clustering (MSC) algorithm is introduced as a valuable alternative to perform materials phase classification from multispectral images. As opposed to other multivariate statistical techniques, such as factor analysis or principal component analysis (PCA), clustering techniques directly assign a class label to each pixel, so that their outputs are phase segmented images, i.e., there is no need for an additional segmentation algorithm. On the other hand, as compared to other clustering procedures and classification methods, such as segmentation by thresholding of multiple spectral components, MSC has the advantages of not requiring previous knowledge of the number of data clusters and not assuming any shape for these clusters, i.e., neither the number nor the composition of the phases must be previously known. This makes MSC a particularly useful tool for exploratory research, assisting phase identification of unknown samples. Visualization and interpretation of the results are also simplified, since the information content of the output image does not depend on the particular choice of the content of the color channels.We applied MSC to the analysis of two sets of X-ray maps acquired in scanning electron microscopes equipped with energy-dispersive detection systems. Our results indicate that MSC is capable of detecting additional phases, not clearly identified through PCA or multiple thresholding, with a very low empirical reject rate.

  10. Particle Rebound and Phase State of Secondary Organic Material

    Science.gov (United States)

    Bateman, A.; Bertram, A. K.; Martin, S. T.

    2014-12-01

    Secondary organic material (SOM) is produced in the atmosphere from the oxidation of volatile organic compounds emitted from anthropogenic and biogenic sources. Aerosol particles, composed in part of SOM, play important roles in climate and air quality by scattering/absorbing radiation and serving as cloud condensation nuclei (CCN). The magnitude of climate-relevant perturbations depends on particle chemical composition, hygroscopic growth, and phase state, among other factors. Herein, the hygroscopic influence on particle rebound and the phase state of particles composed of isoprene, toluene, and α-pinene secondary organic material (SOM) was studied. Particle rebound measurements were obtained from 5 to 95% RH using a three-arm impaction apparatus. The experimentally determined rebound fractions were compared with results from a model of the rebound process that took into account the particle kinetic energy, van der Waals forces, and RH-dependent capillary forces. Comparison of the experimental and modeled indicated particles softened due to water uptake. For low RH values, the model explained the rebound behavior for all studied SOMs. At higher RH values specific to each SOM, however, particle rebound was no longer observed, and the model did not capture this behavior. Calibration experiments using sucrose particles of variable known viscosities showed the transition from non-rebounding to rebounding particles occurred for viscosity values from 100 to 1 Pa s, corresponding to a transition from semisolid to liquid material. The implication of the differing RH-dependent behaviors among the SOMs is that each SOM has a specific and quantitatively different interaction with water. A linear correlation between rebound fraction and hygroscopic growth factor was demonstrated, implying that absorbed water volume is the governing factor of viscosity for the studied classes of SOM. The findings of this study suggest that both the chemical composition and the ambient

  11. Electric-field-assisted crystallisation in phase-change materials

    Energy Technology Data Exchange (ETDEWEB)

    Kohary, Krisztian; Diosdado, Jorge A.V.; Ashwin, Peter; Wright, C. David [College of Engineering, Mathematics, and Physical Sciences, University of Exeter (United Kingdom)

    2012-10-15

    Phase-change materials are of intense research interest due mainly to their use in phase-change memory (PCM) devices that are emerging as a promising technology for future non-volatile, solid-state, electrical storage. Electrically driven transitions from the amorphous to the crystalline phase in such devices exhibit characteristic threshold switching. Several alternative electronic explanations for the origins of this characteristic behaviour have been put forward, for example Poole-Frenkel effects, delocalisation of tail states, field emission processes and space charge limited currents [for a full discussion, see Radielli et al., J. Appl. Phys. 103, 111101 (2008) and Simon et al., MRS Proc. 1251, H01-H011 (2010)]. However, an alternative to these conventional electronic models of threshold switching is based on electric field induced lowering of the system free energy, leading to the field induced nucleation of conducting crystal filaments. In this paper we investigate this alternative view. We present a detailed kinetics study of crystallisation in the presence of an electric field for the phase-change material Ge{sub 2}Sb{sub 2}Te{sub 5}. We derive quantitative crystallisation maps to show the effects of both temperature and electric field on crystallisation and we identify field ranges and parameter values where the electric field might play a significant role. Then we carry out physically realistic simulations of the threshold switching process in typical phase-change device structures, both with and without electric field dependent energy contributions to the system free energy. Our results show that threshold switching can be obtained by a mechanism driven purely by electric field induced nucleation, but the fields so required are large, of the order of 300 MV m{sup -1}, and significantly larger than the experimentally measured threshold fields. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Sb-Te Phase-change Materials under Nanoscale Confinement

    Science.gov (United States)

    Ihalawela, Chandrasiri A.

    Size, speed and efficiency are the major challenges of next generation nonvolatile memory (NVM), and phase-change memory (PCM) has captured a great attention due to its promising features. The key for PCM is rapid and reversible switching between amorphous and crystalline phases with optical or electrical excitation. The structural transition is associated with significant contrast in material properties which can be utilized in optical (CD, DVD, BD) and electronic (PCRAM) memory applications. Importantly, both the functionality and the success of PCM technology significantly depend on the core material and its properties. So investigating PC materials is crucial for the development of PCM technology to realized enhanced solutions. In regards to PC materials, Sb-Te binary plays a significant role as a basis to the well-known Ge-Sb-Te system. Unlike the conventional deposition methods (sputtering, evaporation), electrochemical deposition method is used due to its multiple advantages, such as conformality, via filling capability, etc. First, the controllable synthesis of Sb-Te thin films was studied for a wide range of compositions using this novel deposition method. Secondly, the solid electrolytic nature of stoichiometric Sb2Te3 was studied with respect to precious metals. With the understanding of 2D thin film synthesis, Sb-Te 1D nanowires (18 - 220 nm) were synthesized using templated electrodeposition, where nanoporous anodic aluminum oxide (AAO) was used as a template for the growth of nanowires. In order to gain the controllability over the deposition in high aspect ratio structures, growth mechanisms of both the thin films and nanowires were investigated. Systematic understanding gained thorough previous studies helped to formulate the ultimate goal of this dissertation. In this dissertation, the main objective is to understand the size effect of PC materials on their phase transition properties. The reduction of effective memory cell size in conjunction with

  13. Microencapsulated Phase Change Composite Materials for Energy Efficient Buildings

    Science.gov (United States)

    Thiele, Alexander

    This study aims to elucidate how phase change material (PCM)-composite materials can be leveraged to reduce the energy consumption of buildings and to provide cost savings to ratepayers. Phase change materials (PCMs) can store thermal energy in the form of latent heat when subjected to temperatures exceeding their melting point by undergoing a phase transition from solid to liquid state. Reversibly, PCMs can release this thermal energy when the system temperature falls below their solidification point. The goal in implementing composite PCM walls is to significantly reduce and time-shift the maximum thermal load on the building in order to reduce and smooth out the electricity demand for heating and cooling. This Ph.D. thesis aims to develop a set of thermal design methods and tools for exploring the use of PCM-composite building envelopes and for providing design rules for their practical implementation. First, detailed numerical simulations were used to show that the effective thermal conductivity of core-shell-matrix composites depended only on the volume fraction and thermal conductivity of the constituent materials. The effective medium approximation reported by Felske (2004) was in very good agreement with numerical predictions of the effective thermal conductivity. Second, a carefully validated transient thermal model was used to simulate microencapsulated PCM-composite walls subjected to diurnal or annual outdoor temperature and solar radiation flux. It was established that adding microencapsulated PCM to concrete walls both substantially reduced and delayed the thermal load on the building. Several design rules were established, most notably, (i) increasing the volume fraction of microencapsulated PCM within the wall increases the energy savings but at the potential expense of mechanical properties [1], (ii) the phase change temperature leading to the maximum energy and cost savings should equal the desired indoor temperature regardless of the climate

  14. Artefacts in geometric phase analysis of compound materials

    Energy Technology Data Exchange (ETDEWEB)

    Peters, Jonathan J.P., E-mail: j.j.p.peters@warwick.ac.uk [Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL (United Kingdom); Beanland, Richard; Alexe, Marin [Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL (United Kingdom); Cockburn, John W.; Revin, Dmitry G.; Zhang, Shiyong Y. [Department of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield S3 7RH (United Kingdom); Sanchez, Ana M., E-mail: a.m.sanchez@warwick.ac.uk [Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL (United Kingdom)

    2015-10-15

    The geometric phase analysis (GPA) algorithm is known as a robust and straightforward technique that can be used to measure lattice strains in high resolution transmission electron microscope (TEM) images. It is also attractive for analysis of aberration-corrected scanning TEM (ac-STEM) images that resolve every atom column, since it uses Fourier transforms and does not require real-space peak detection and assignment to appropriate sublattices. Here it is demonstrated that, in ac-STEM images of compound materials with compositionally distinct atom columns, an additional geometric phase is present in the Fourier transform. If the structure changes from one area to another in the image (e.g. across an interface), the change in this additional phase will appear as a strain in conventional GPA, even if there is no lattice strain. Strategies to avoid this pitfall are outlined. - Highlights: • GPA is shown to produce incorrect strains when applied to images of compound materials. • A mathematical description is laid out for why GPA can produce artefacts. • The artefact is demonstrated using experimental and simulated data. • A ‘rule’ is set to avoid this artefact in GPA.

  15. Study of Phase Change Materials Applied to CPV Receivers

    Directory of Open Access Journals (Sweden)

    Zun-Hao Shih

    2015-01-01

    Full Text Available There are lots of factors which can directly affect output efficiency of photovoltaic device. One of them is high temperature which would cause adverse effect to solar cell. When solar cell is operated in high temperature, the cell’s output efficiency will become low. Therefore, improving thermal spreading of solar cell is an important issue. In this study, we focused on finding new materials to enhance the thermal dispreading and keep the temperature of solar cell as low as possible. The new materials are different from conventional metal ones; they are called “phase change materials (PCMs” which are mainly applied to green buildings. We chose two kinds of PSMs to study their thermal dispreading ability and to compare them with traditional aluminum material. These two kinds of PCMs are wax and lauric acid. We made three aluminum-based cuboids as heat sinking units and two of them were designed with hollow space to fill in the PCMs. We applied electric forward bias on solar cells to simulate the heat contributed from the concentrated sunlight. Then we observed the thermal distribution of these three kinds of thermal spreading materials. Two levels of forward biases were chosen to test the samples and analyze the experiment results.

  16. The Study of the Thermoelectric Properties of Phase Change Materials

    Science.gov (United States)

    Yin, Ming; Abdi, Mohammed; Noimande, Zibusisu; Mbamalu, Godwin; Alameeri, Dheyaa; Datta, Timir

    We study thermoelectric property that is electrical phenomena occurring in conjunction with the flow of heat of phase-change materials (PCM) in particular GeSbTe (GST225). From given sets of material parameters, COMSOL Multiphysics heat-transfer module is used to compute maps of temperature and voltage distribution in the PCM samples. These results are used to design an apparatus including the variable temperature sample holder set up. An Arbitrary/ Function generator and a circuit setup is also designed to control the alternation of heaters embedded on the sample holder in order to ensure sequential back and forward flow of heat current from both sides of the sample. Accurate values of potential differences and temperature distribution profiles are obtained in order to compute the Seebeck coefficient of the sample. The results of elemental analysis and imaging studies such as XRD, UV-VIS, EDEX and SEM of the sample are obtained. Factors affecting the thermoelectric properties of phase change memory are also discussed. NNSA/ DOD Consortium for Materials and Energy Studies.

  17. Thermal performance of sodium acetate trihydrate thickened with different materials as phase change energy storage material

    Energy Technology Data Exchange (ETDEWEB)

    Cabeza, L.F. [Universitat de Lleida (Spain); Svensson, G.; Hiebler, S.; Mehling, H. [ZAE Bayern, Garching (Germany)

    2003-09-01

    The use of phase change materials (PCMs) in energy storage has the advantage of high energy density and isothermal operation. Although the use of only non-segregating PCMs is a good commercial approach, some desirable PCM melting points do not seem attainable with non-segregating salt hydrates at a reasonable price. The addition of gellants and thickeners can avoid segregation of these materials. In this paper, sodium acetate trihydrate is successfully thickened with bentonite and starch. Cellulose gives an even better thickened PCM, but temperatures higher than 65 {sup o}C give phase separation. The mixtures would show a similar thermal behavior as the salt hydrate, with the same melting point and an enthalpy decrease between 20% and 35%, depending on the type and amount of thickening material used. (Author)

  18. Design of materials with extreme thermal expansion using a three-phase topology optimization method

    DEFF Research Database (Denmark)

    Sigmund, Ole; Torquato, S.

    1997-01-01

    Composites with extremal or unusual thermal expansion coefficients are designed using a three-phase topology optimization method. The composites are made of two different material phases and a void phase. The topology optimization method consists in finding the distribution of material phases...... materials having maximum directional thermal expansion (thermal actuators), zero isotropic thermal expansion, and negative isotropic thermal expansion. It is shown that materials with effective negative thermal expansion coefficients can be obtained by mixing two phases with positive thermal expansion...

  19. Phase I. Lanthanum-based Start Materials for Hydride Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Gschneidner, K. A. [Ames Lab., Ames, IA (United States); Schmidt, F. A. [Ames Lab., Ames, IA (United States); Frerichs, A. E. [Ames Lab., Ames, IA (United States); Ament, K. A. [Ames Lab., Ames, IA (United States)

    2013-08-20

    The purpose of Phase I of this work is to focus on developing a La-based start material for making nickel-metal (lanthanum)-hydride batteries based on our carbothermic-silicon process. The goal is to develop a protocol for the manufacture of (La1-xRx)(Ni1-yMy)(Siz), where R is a rare earth metal and M is a non-rare earth metal, to be utilized as the negative electrode in nickel-metal hydride (NiMH) rechargeable batteries.

  20. Phase Change Materials for Thermal Management of IC Packages

    Directory of Open Access Journals (Sweden)

    P. Fiala

    2007-06-01

    Full Text Available This paper deals with the application of phase change materials (PCM for thermal management of integrated circuits as a viable alternative to active forced convection cooling systems. The paper presents an analytical description and solution of heat transfer, melting and freezing process in 1D which is applied to inorganic crystalline salts. There are also results of numerical simulation of a real 3D model. These results were obtained by means of the finite element method (FEM. Results of 3D numerical solutions were verified experimentally.

  1. Electronic transport in amorphous phase-change materials

    Energy Technology Data Exchange (ETDEWEB)

    Luckas, Jennifer Maria

    2012-09-14

    Phase change materials combine a pronounced contrast in resistivity and reflectivity between their disordered amorphous and ordered crystalline state with very fast crystallization kinetics. Due to this exceptional combination of properties phase-change materials find broad application in non-volatile optical memories such as CD, DVD or Bluray Disc. Furthermore, this class of materials demonstrates remarkable electrical transport phenomena in their disordered state, which have shown to be crucial for their application in electronic storage devices. The threshold switching phenomenon denotes the sudden decrease in resistivity beyond a critical electrical threshold field. The threshold switching phenomenon facilitates the phase transitions at practical small voltages. Below this threshold the amorphous state resistivity is thermally activated and is observed to increase with time. This effect known as resistance drift seriously hampers the development of multi-level storage devices. Hence, understanding the physical origins of threshold switching and resistance drift phenomena is crucial to improve non-volatile phase-change memories. Even though both phenomena are often attributed to localized defect states in the band gap, the defect state density in amorphous phase-change materials has remained poorly studied. Starting from a brief introduction of the physics of phase-change materials this thesis summarizes the most important models behind electrical switching and resistance drift with the aim to discuss the role of localized defect states. The centerpiece of this thesis is the investigation of defects state densities in different amorphous phase-change materials and electrical switching chalcogenides. On the basis of Modulated Photo Current (MPC) Experiments and Photothermal Deflection Spectroscopy, a sophisticated band model for the disordered phase of the binary phase-change alloy GeTe has been developed. By this direct experimental approach the band-model for a

  2. Pickering Emulsification to Mass Produce Nanoencapsulated Phase-change-material

    Science.gov (United States)

    Wang, Xuezhen; Zhang, Lecheng; Yu, Yi-Hsien; Mannan, S. Sam; Chen, Ying; Cheng, Zhengdong; Cheng's Group Team, Dr.

    2015-03-01

    Phase changing materials (PCM) have useful applications in thermal management. However, mass production of micro and nano encapsulated PCM has been a challenge. Here, we present a simple and scalable method via a two-step Pickering emulsification method. We have developed interface active nanoplates by asymmetric modification of nanoplates of layered crystal materials. Nanoencapsulated PCM is realized with exfoliated monolayer nanoplates surfactants using very little energy input for emulsification. Further chemical reactions are performed to convert the emulsions into core-shell structures. The resulted capsules are submicron in size with remarkable uniformity in size distribution. DSC characterization showed that the capsulation efficiency of NEPCM was 58.58% and were thermal stable which was characterized by the DSC data for the sample after 200 thermal cycling.

  3. Review on phase change materials for building applications

    Directory of Open Access Journals (Sweden)

    Lavinia SOCACIU

    2014-11-01

    Full Text Available In nowadays, the Phase Change Material (PCM is a viable alternative for reducing the energy consumption and for increase the thermal comfort in buildings. The use of PCM in building applications provides the potential to increase the indoor thermal comfort for occupants due to the reduced indoor temperature fluctuations and lower global energy consumption. The possibility to incorporate the PCM into the material of construction for cooling and heating the buildings gained the interest of researchers from all the world because the PCM have a high heat of fusion, meaning it is capable to storing and release large amounts of energy in the form of heat during its melting and solidifying process at a specific temperature.

  4. Determining material parameters using phase-field simulations and experiments

    DEFF Research Database (Denmark)

    Zhang, Jin; Poulsen, Stefan O.; Gibbs, John W.

    2017-01-01

    A method to determine material parameters by comparing the evolution of experimentally determined 3D microstructures to simulated 3D microstructures is proposed. The temporal evolution of a dendritic solid-liquid mixture is acquired in situ using x-ray tomography. Using a time step from these dat...... variation of the best-fit parameters and the fidelity of the fitting. We find a liquid diffusion coefficient that is different from that measured using directional solidification....... as an initial condition in a phase-field simulation, the computed structure is compared to that measured experimentally at a later time. An optimization technique is used to find the material parameters that yield the best match of the simulated microstructure to the measured microstructure in a global manner...

  5. Research on phase-change material building mass applied in the air-conditioning field

    Institute of Scientific and Technical Information of China (English)

    YANQuanying

    2003-01-01

    Phase-change material building mass contains phase-change matenals. It can decrease air-conditioning load and indoor temperature fluctuations, and improve comfort degree in summer because of thermal storage property of phase-change material. Thereby, the scale, initial investment and operational cost of air-conditioning system decrease effectively. The indoor surroundings improve. In this paper, suitable phase-change material used in architecture and combination mode between phase change material and architectural material were studied. By considering the properties of materials, such as phase-change temperature, phase-change latent heat, thermal conductivity and expansion coefficient, phase-change materials were selected and evaluated. Combination mode between phase-change material and architectural material were provided. The influence of phase-change material structure on thermal performance in room and energy-saving effect were analyzed and compared with traditional structure without phase-change material. It is proved that phase-change material structure is feasible in the practical engineenng. These provide the basis for developing phase-change material building mass.

  6. Phase Change Material Heat Sink for an ISS Flight Experiment

    Science.gov (United States)

    Quinn, Gregory; Stieber, Jesse; Sheth, Rubik; Ahlstrom, Thomas

    2015-01-01

    A flight experiment is being constructed to utilize the persistent microgravity environment of the International Space Station (ISS) to prove out operation of a microgravity compatible phase change material (PCM) heat sink. A PCM heat sink can help to reduce the overall mass and volume of future exploration spacecraft thermal control systems (TCS). The program is characterizing a new PCM heat sink that incorporates a novel phase management approach to prevent high pressures and structural deformation that often occur with PCM heat sinks undergoing cyclic operation in microgravity. The PCM unit was made using brazed aluminum construction with paraffin wax as the fusible material. It is designed to be installed into a propylene glycol and water cooling loop, with scaling consistent with the conceptual designs for the Orion Multipurpose Crew Vehicle. This paper reports on the construction of the PCM heat sink and on initial ground test results conducted at UTC Aerospace Systems prior to delivery to NASA. The prototype will be tested later on the ground and in orbit via a self-contained experiment package developed by NASA Johnson Space Center to operate in an ISS EXPRESS rack.

  7. An investigation on phase change materials to reduce summer overheating

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, S.; Kornadt, O. [Bauhaus-University Weimar, Weimar (Germany). Dept. of Building Physics

    2006-07-01

    The overheating problem in office buildings can be partially attributed to modern architectural constructions with high glazing facades and light-weight constructions. One way to solve the problem is to use phase change materials (PCMs) which are heat accumulators that store and release heat during the phase change process. PCMs increase the thermal mass in buildings and help reduce peak temperatures during summer hot spells. This study examined the heat storing effect of PCMs and their potential use in the building sector. In particular, 2 PCMs were examined in full scale experiments at the Bauhaus-University Weimar. The study examined the effects of PCMs placed on the surface of inner partitioning, ceilings or floors that could be numerically treated as a separate layer with room-side heat transfer one side and heat conduction to the next layers on the other side. Experimental results led to the development of a numerical description of the phase change process with and without super-cooling. The numerical description was based on temperature dependent functions for heat capacity and thermal conductivity. This presentation described the validation, stability and accuracy of the model and proposed recommendations. Simulation results of PCM-plaster with micro-encapsulated paraffin show the potential of a marketable material. In addition to optimizing the melting temperature and layer thickness, an important criterion for PCM efficiency is the number of overheating hours that can be reduced. For a European climate, a 3 cm layer thick PCM plaster with optimized peak temperature can reduce overheating hours by 25 to 50 per cent. 15 refs., 1 tab., 8 figs.

  8. Analysis of microencapsulated phase change material slurries and phase change material emulsions as heat transfer fluid and thermal storage material

    OpenAIRE

    Delgado Gracia, Mónica; Zalba Nonay, Belen; Lázaro Fernández, Ana

    2013-01-01

    La presente tesis doctoral trata el análisis de suspensiones y emulsiones de materiales de cambio de fase para su uso como fluido caloportador y material de almacenamiento térmico. El interés de la tesis nace de la actual conyuntura energética. Dentro de la línea de búsqueda de un modelo energético sostenible, el almacenamiento térmico de energía contribuye a la utilización eficiente de la energía. Las aplicaciones del almacenamiento térmico de energía mediante cambio de fase sólido-líquido s...

  9. Micro-encapsulated phase-change materials integrated into construction materials

    Energy Technology Data Exchange (ETDEWEB)

    Schossig, P.; Henning, H.-M.; Gschwander, S. [Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstr. 2, 79110 Freiburg (Germany); Haussmann, T. [PSE GmbH-Forschung, Entwicklung, Marketing Solar Info Center, 79072 Freiburg (Germany)

    2005-11-15

    The idea of improving the thermal comfort of lightweight buildings by integrating phase-change materials (PCMs) into the building structure has been investigated in various research projects over several decades. Most of these attempts applied macro-capsules or direct immersion processes, which both turned out to present several drawbacks. Due to these problems, none of these PCM products was successful in the wider market. The new option to micro-encapsulate PCMs, a key technology which overcomes many of these problems, may make PCM products accessible for the building industry. This paper describes the work done at Fraunhofer ISE within a German government-funded project over the last 5 years, extending from building simulations to first measurements of full-size rooms equipped with PCM. The first products are now available on the market. (author) [Phase change material; Passive cooling; Energy efficient building; Microencapsulation].

  10. Electronic transport in amorphous phase-change materials

    Energy Technology Data Exchange (ETDEWEB)

    Luckas, Jennifer Maria

    2012-09-14

    Phase change materials combine a pronounced contrast in resistivity and reflectivity between their disordered amorphous and ordered crystalline state with very fast crystallization kinetics. Due to this exceptional combination of properties phase-change materials find broad application in non-volatile optical memories such as CD, DVD or Bluray Disc. Furthermore, this class of materials demonstrates remarkable electrical transport phenomena in their disordered state, which have shown to be crucial for their application in electronic storage devices. The threshold switching phenomenon denotes the sudden decrease in resistivity beyond a critical electrical threshold field. The threshold switching phenomenon facilitates the phase transitions at practical small voltages. Below this threshold the amorphous state resistivity is thermally activated and is observed to increase with time. This effect known as resistance drift seriously hampers the development of multi-level storage devices. Hence, understanding the physical origins of threshold switching and resistance drift phenomena is crucial to improve non-volatile phase-change memories. Even though both phenomena are often attributed to localized defect states in the band gap, the defect state density in amorphous phase-change materials has remained poorly studied. Starting from a brief introduction of the physics of phase-change materials this thesis summarizes the most important models behind electrical switching and resistance drift with the aim to discuss the role of localized defect states. The centerpiece of this thesis is the investigation of defects state densities in different amorphous phase-change materials and electrical switching chalcogenides. On the basis of Modulated Photo Current (MPC) Experiments and Photothermal Deflection Spectroscopy, a sophisticated band model for the disordered phase of the binary phase-change alloy GeTe has been developed. By this direct experimental approach the band-model for a

  11. Materials Research Society Symposia Proceedings, Volume 19. Alloy Phase Diagrams Held November 1982 in Boston, Massachusetts.

    Science.gov (United States)

    Alloys, * Phase diagrams , *Symposia, Stability, Thermodynamic properties, Models, Solidification, Chemical equilibrium, Microstructure, Metallurgy, Structural analysis, Research management, Materials

  12. Structure of covalently bonded materials: From the Peierls distortion to Phase-Change Materials

    Science.gov (United States)

    Gaspard, Jean-Pierre

    2016-03-01

    The relation between electronic structure and cohesion of materials has been a permanent quest of Jacques Friedel and his school. He developed simple models that are of great value as guidelines in conjunction with ab initio calculations. His local approach of bonding has both the advantages of a large field of applications including non-crystalline materials and a common language with chemists. Along this line, we review some fascinating behaviors of covalent materials, most of them showing a Peierls (symmetry breaking) instability mechanism, even in liquid and amorphous materials. We analyze the effect of external parameters such as pressure and temperature. In some temperature ranges, the Peierls distortion disappears and a negative thermal expansion is observed. In addition, the Peierls distortion plays a central role in Phase-Change Materials, which are very promising non-volatile memories. Son approche locale de la liaison chimique s'applique à un vaste champ de systèmes, incluant les matériaux non cristallins et permis un langage commun avec les chimistes. Dans cet axe nous passons en revue quelques comportements fascinants des matériaux covalents, la plupart d'entre eux présentant un mécanisme d'instabilité de Peierls (brisure de symétrie), même les liquides et les amorphes, étonnamment. Nous analysons aussi l'effet de parame'tres externes tels que la pression et la température. Dans un certain domaine de température, la distorsion de Peierls disparaît et une dilatation thermique négative est observée. Enfin, la distorsion de Peierls joue un rôle central dans les matériaux à changement de phase (PC materials), qui sont très prometteurs pour la réalisation de mémoires non volatiles.

  13. Plastic phase change material and articles made therefrom

    Science.gov (United States)

    Abhari, Ramin

    2016-04-19

    The present invention generally relates to a method for manufacturing phase change material (PCM) pellets. The method includes providing a melt composition, including paraffin and a polymer. The paraffin has a melt point of between about 10.degree. C. and about 50.degree. C., and more preferably between about 18.degree. C. and about 28.degree. C. In one embodiment, the melt composition includes various additives, such as a flame retardant. The method further includes forming the melt composition into PCM pellets. The method further may include the step of cooling the melt to increase the melt viscosity before pelletizing. Further, PCM compounds are provided having an organic PCM and a polymer. Methods are provided to convert the PCM compounds into various form-stable PCMs. A method of coating the PCMs is included to provide PCMs with substantially no paraffin seepage and with ignition resistance properties.

  14. Plastic phase change material and articles made therefrom

    Energy Technology Data Exchange (ETDEWEB)

    Abhari, Ramin

    2016-04-19

    The present invention generally relates to a method for manufacturing phase change material (PCM) pellets. The method includes providing a melt composition, including paraffin and a polymer. The paraffin has a melt point of between about 10.degree. C. and about 50.degree. C., and more preferably between about 18.degree. C. and about 28.degree. C. In one embodiment, the melt composition includes various additives, such as a flame retardant. The method further includes forming the melt composition into PCM pellets. The method further may include the step of cooling the melt to increase the melt viscosity before pelletizing. Further, PCM compounds are provided having an organic PCM and a polymer. Methods are provided to convert the PCM compounds into various form-stable PCMs. A method of coating the PCMs is included to provide PCMs with substantially no paraffin seepage and with ignition resistance properties.

  15. Cooling of mobile electronic devices using phase change materials

    Energy Technology Data Exchange (ETDEWEB)

    Tan, F.L.; Tso, C.P. [Nanyang Technological University (Singapore). School of Mechanical and Production Engineering

    2004-02-01

    An experimental study is conducted on the cooling of mobile electronic devices, such as personal digital assistants (PDAs) and wearable computers, using a heat storage unit (HSU) filled with the phase change material (PCM) of n-eicosane inside the device. The high latent heat of n-eicosane in the HSU absorbs the heat dissipation from the chips and can maintain the chip temperature below the allowable service temperature of 50{sup o}C for 2 h of transient operations of the PDA. The heat dissipation of the chips inside a PDA and the orientation of the HSU are experimentally investigated in this paper. It was found that different orientation of the HSU inside the PDA could affect significantly the temperature distribution. (author)

  16. Enhancing the performance of BICPV systems using phase change materials

    Science.gov (United States)

    Sharma, Shivangi; Sellami, Nazmi; Tahir, Asif; Reddy, K. S.; Mallick, Tapas K.

    2015-09-01

    Building Integrated Concentrated Photovoltaic (BICPV) systems have three main benefits for integration into built environments, namely, (i) generating electricity at the point of use (ii) allowing light efficacy within the building envelope and (iii) providing thermal management. In this work, to maintain solar cell operating temperature and improve its performance, a phase change material (PCM) container has been designed, developed and integrated with the BICPV system. Using highly collimated continuous light source, an indoor experiment was performed. The absolute electrical power conversion efficiency for the module without PCM cooling resulted in 7.82% while using PCM increased it to 9.07%, thus showing a relative increase by 15.9% as compared to a non- PCM system. A maximum temperature reduction of 5.2°C was also observed when the BICPV module was integrated with PCM containment as compared to the BICPV system without any PCM containment.

  17. Force law in material media, hidden momentum and quantum phases

    Energy Technology Data Exchange (ETDEWEB)

    Kholmetskii, Alexander L., E-mail: alkholmetskii@gmail.com [Belarusian State University, Minsk (Belarus); Missevitch, Oleg V. [Institute for Nuclear Problems, Belarusian State University, Minsk (Belarus); Yarman, T. [Okan University, Akfirat, Istanbul (Turkey); Savronik, Eskisehir (Turkey)

    2016-06-15

    We address to the force law in classical electrodynamics of material media, paying attention on the force term due to time variation of hidden momentum of magnetic dipoles. We highlight that the emergence of this force component is required by the general theorem, deriving zero total momentum for any static configuration of charges/currents. At the same time, we disclose the impossibility to add this force term covariantly to the Lorentz force law in material media. We further show that the adoption of the Einstein–Laub force law does not resolve the issue, because for a small electric/magnetic dipole, the density of Einstein–Laub force integrates exactly to the same equation, like the Lorentz force with the inclusion of hidden momentum contribution. Thus, none of the available expressions for the force on a moving dipole is compatible with the relativistic transformation of force, and we support this statement with a number of particular examples. In this respect, we suggest applying the Lagrangian approach to the derivation of the force law in a magnetized/polarized medium. In the framework of this approach we obtain the novel expression for the force on a small electric/magnetic dipole, with the novel expression for its generalized momentum. The latter expression implies two novel quantum effects with non-topological phases, when an electric dipole is moving in an electric field, and when a magnetic dipole is moving in a magnetic field. These phases, in general, are not related to dynamical effects, because they are not equal to zero, when the classical force on a dipole is vanishing. The implications of the obtained results are discussed.

  18. Analysis of wallboard containing a phase change material

    Science.gov (United States)

    Tomlinson, J. J.; Heberle, D. P.

    Phase change materials (PCMs) used on the interior of buildings hold the promise for improved thermal performance by reducing the energy requirements for space conditioning and by improving thermal comfort by reducing temperature swings inside the building. Efforts are underway to develop a gypsum wallboard containing a hydrocarbon PCM. With a phase change temperature in the room temperature range, the PCM wallboard adds substantially to the thermal mass of the building while serving the same architectural function as conventional wallboard. To determine the thermal and economic performance of this PCM wallboard, the Transient Systems Simulation Program (TRNSYS) was modified to accommodate walls that are covered with PCM plasterboard, and to apportion the direct beam solar radiation to interior surfaces of a building. The modified code was used to simulate the performance of conventional and direct-gain passive solar residential-sized buildings with and without PCM wallboard. Space heating energy savings were determined as a function of PCM wallboard characteristics. Thermal comfort improvements in buildings containing the PCM were qualified in terms of energy savings. The report concludes with a present worth economic analysis of these energy savings and arrives at system costs and economic payback based on current costs of PCMs under study for the wallboard application.

  19. Enabling tunable micromechanical bandpass filters through phase-change materials

    Science.gov (United States)

    Cao, Yunqi; Torres, David; Wang, Tongyu; Tan, Xiaobo; Sepúlveda, Nelson

    2017-08-01

    Vanadium dioxide (VO2), one of the most promising phase-change smart materials, has shown strong frequency tuning capabilities in MEMS resonators. In this paper, we demonstrate the potential use of VO2-based MEMS devices as second-order kilohertz (kHz) bandpass filters with tunable band selectivity and adjustable bandwidth (BW). Two identical on-chip micro resonators are actuated using mechanical excitation and measured using optical detection. One of the resonators is not actuated while the other is tuned by applying electric currents across an integrated resistive heater, which induces the phase transition of the VO2, and consequently a large stress to the mechanical structure. The responses of both MEMS resonators are combined, resulting in a resonant peak of tunable BW controlled by the input current. The BW can be extended to 2.62 times by using two bridges or 2.39 times by implementing one pair of cantilevers. The results for both devices are discussed.

  20. Subscale Water Based Phase Change Material Heat Exchanger Development

    Science.gov (United States)

    Sheth, Rubik; Hansen, Scott

    2016-01-01

    Supplemental heat rejection devices are required in many spacecraft as the radiators are not sized to meet the full heat rejection demand. One means of obtaining additional heat rejection is through the use of phase change material heat exchangers (PCM HX's). PCM HX's utilize phase change to store energy in unfavorable thermal environments (melting) and reject the energy in favorable environments (freezing). Traditionally, wax has been used as a PCM on spacecraft. However, water is an attractive alternative because it is capable of storing about 40% more energy per unit mass due to its higher latent heat of fusion. The significant problem in using water as a PCM is its expansion while freezing, leading to structural integrity concerns when housed in an enclosed heat exchanger volume. Significant investigation and development has taken place over the past five years to understand and overcome the problems associated with water PCM HX's. This paper reports on the final efforts by Johnson Space Center's Thermal Systems Branch to develop a water based PCM HX. The test article developed and reported on is a subscale version of the full-scale water-based PCM HX's constructed by Mezzo Technologies. The subscale unit was designed by applying prior research on freeze front propagation and previous full-scale water PCM HX development. Design modifications to the subscale unit included use of urethane bladder, decreased aspect ratio, perforated protection sheet, and use of additional mid-plates. Testing of the subscale unit was successful and 150 cycles were completed without fail.

  1. Pressure-induced phase transition in silicon nitride material

    Institute of Scientific and Technical Information of China (English)

    Chen Dong; Yu Ben-Hai

    2013-01-01

    The equilibrium crystal structures,lattice parameters,elastic constants,and elastic moduli of the polymorphs α-,β-,and γ-Si3N4,have been calculated by first-principles method.β-Si3N4 is ductile in nature and has an ionic bonding.γ-Si3N4 is found to be a brittle material and has covalent chemical bonds,especially at high pressures.The phase boundary of the β → γ transition is obtained and a positive slope is found.This indicates that at higher temperatures it requires higher pressures to synthesize γ-Si3N4.On the other hand,the α → γ phase boundary can be described as P =14.37198 + 3.27 × 10-3T-7.83911 × 10-7T2-3.13552 × 10-10T3.The phase transition from α-to γ-Si3N4 occurs at 16.1 GPa and 1700 K.Then,the dependencies of bulk modulus,heat capacity,and thermal expansion on the pressure P are obtained in the ranges of 0 GPa-30 GPa and 0 K-2000 K.Significant features in these properties are observed at high temperatures.It turns out that the thermal expansion of γ-Si3N4 is larger than that of α-Si3N4 over wide pressure and temperature ranges.The evolutions of the heat capacity with temperature for the Si3N4 polymorphs are close to each other,which are important for possible applications of Si3N4.

  2. NASA Johnson Space Center Small Business Innovation Research (SBIR) Successes, Infusion and Commercializations and Potential International Partnering Opportunities

    Science.gov (United States)

    Packard, Kathryn; Goodman, Doug; Whittington, James

    2016-01-01

    The NASA Small Business Innovation Research (SBIR) Program has served as a beneficial funding vehicle to both US small technology businesses and the Federal Agencies that participate in the program. This paper, to the extent possible, while observing Intellectual Property (IP) laws, will discuss the many SBIR and STTR (SBIR Technology Transfer) successes in the recent history of the NASA Johnson Space Center (JSC). Many of the participants of the International Conference on Environmental Systems (ICES) have based their research and papers on technologies that were made possible by SBIR/STTR awards and post award funding. Many SBIR/STTR successes have flown on Space Shuttle missions, Space X Dragons, and other spacecraft. SBIR/STTR technologies are currently infused on the International Space Station (ISS) and satellites, one of which was a NASA/JAXA (Japanese Space Agency) joint venture. Many of these companies have commercialized their technologies and grown as businesses while helping the economy through the creation of new jobs. In addition, this paper will explore the opportunity for international partnership with US SBIR/STTR companies as up to 49% of the makeup of the company is not required to be American owned. Although this paper will deal with technical achievements, it does not purport to be technical in nature. It will address the many requests for information on successes and opportunities within NASA SBIR and the virtually untapped potential of international partnering.

  3. Water Based Phase Change Material Heat Exchanger Development

    Science.gov (United States)

    Hansen, Scott W.; Sheth, Ribik B.; Atwell, Matt; Cheek, Ann; Agarwal, Muskan; Hong, Steven; Patel, Aashini,; Nguyen, Lisa; Posada, Luciano

    2014-01-01

    In a cyclical heat load environment such as low Lunar orbit, a spacecraft’s radiators are not sized to reject the full heat load requirement. Traditionally, a supplemental heat rejection device (SHReD) such as an evaporator or sublimator is used to act as a “topper” to meet the additional heat rejection demands. Utilizing a Phase Change Material (PCM) heat exchanger (HX) as a SHReD provides an attractive alternative to evaporators and sublimators as PCM HXs do not use a consumable, thereby leading to reduced launch mass and volume requirements. Studies conducted in this paper investigate utilizing water’s high latent heat of formation as a PCM, as opposed to traditional waxes, and corresponding complications surrounding freezing water in an enclosed volume. Work highlighted in this study is primarily visual and includes understanding ice formation, freeze front propagation, and the solidification process of water/ice. Various test coupons were constructed of copper to emulate the interstitial pin configuration (to aid in conduction) of the proposed water PCM HX design. Construction of a prototypic HX was also completed in which a flexible bladder material and interstitial pin configurations were tested. Additionally, a microgravity flight was conducted where three copper test articles were frozen continuously during microgravity and 2-g periods and individual water droplets were frozen during microgravity.

  4. High Pressure Materials Research: Novel Extended Phases of Molecular Triatomics

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, C

    2004-05-26

    Application of high pressure significantly alters the interatomic distance and thus the nature of intermolecular interaction, chemical bonding, molecular configuration, crystal structure, and stability of solid [1]. With modern advances in high-pressure technologies [2], it is feasible to achieve a large (often up to a several-fold) compression of lattice, at which condition material can be easily forced into a new physical and chemical configuration [3]. The high-pressure thus offers enhanced opportunities to discover new phases, both stable and metastable ones, and to tune exotic properties in a wide-range of atomistic length scale, substantially greater than (often being several orders of) those achieved by other thermal (varying temperatures) and chemical (varying composition or making alloys) means. Simple molecular solids like H{sub 2}, C, CO{sub 2}, N{sub 2}, O{sub 2}, H{sub 2}O, CO, NH{sub 3}, and CH{sub 4} are bounded by strong covalent intramolecular bonds, yet relatively weak intermolecular bonds of van der Waals and/or hydrogen bonds. The weak intermolecular bonds make these solids highly compressible (i.e., low bulk moduli typically less than 10 GPa), while the strong covalent bonds make them chemically inert at least initially at low pressures. Carbon-carbon single bonds, carbon-oxygen double bonds and nitrogen-nitrogen triple bonds, for example, are among the strongest. These molecular forms are, thus, often considered to remain stable in an extended region of high pressures and high temperatures. High stabilities of these covalent molecules are also the basis of which their mixtures are often presumed to be the major detonation products of energetic materials as well as the major constituents of giant planets. However, their physical/chemical stabilities are not truly understood at those extreme pressure-temperature conditions. In fact, an increasing amount of experimental evidences contradict the assumed stability of these materials at high

  5. Waveguide Phase Modulator for Integrated Planar Lightwave Circuits in KTP Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I effort proposes the development of a potassium titanyl phosphate (KTP) waveguide phase modulator for future integration into a Planar Lightwave...

  6. Design and Development of a compact and ruggest phase and flouresence microscope for space utilization Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this SBIR Phase 1 we propose to develop a novel microscope by integrating Fourier phase contrast microscopy (FPCM) and epi-fluorescence microscopy. In FPCM, the...

  7. 美国SBIRS-HEO卫星预警能力分析%Analysis on Early Warning Capability of USA’s SBIRS-HEO Satellite

    Institute of Scientific and Technical Information of China (English)

    毛艺帆; 张多林; 王路

    2014-01-01

    The space-based infrared system(SBIRS)is the most advanced space-based early warning system, and also in the midst of developing and perfecting constantly. The paper mainly studies the HEO (highly elliptical orbit), explores the modeling and simulation aiming at the coverage characteristic and the detecting capability, and analyses the work performance on orbit.%美国天基红外系统(SBIRS)是现今最先进的天基预警系统,并且还在不断地发展完善当中。重点研究 SBIRS-High 中的大椭圆轨道卫星,具体针对其覆盖范围和探测能力进行了建模及仿真,对其在轨工作性能进行了初步分析。

  8. Polymer Matrix Composite Materials for Lightning Strike Mitigation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this phase I SBIR program, a team led by Advanced Ceramics Research Inc. (ACR) propose a novel, low-cost manufacturing process for multi-functional polymer...

  9. Free-cooling of buildings with phase change materials

    Energy Technology Data Exchange (ETDEWEB)

    Zalba, B.; Marin, J.M. [Universidad de Zaragoza Maria de Luna (Spain). Departamento de Ingenieria Mecanica; Cabeza, L.F. [Universitat de Lleida (Spain). Departamento d' Informatica i Eng. Industrial; Mehling, H. [ZAE Bayern, Abt. 1 Energy Conversion and Storage, Garching (Germany)

    2004-12-01

    In this paper, the application of phase change materials (PCM) in free-cooling systems is studied. Free-cooling is understood as a means to store outdoors coolness during the night, to supply indoors cooling during the day. The use of PCMs is suitable because of the small temperature difference between day indoors and night outdoors. An installation that allows testing the performance of PCMs in such systems was designed and constructed. The main influence parameters like ratio of energy/volume in the encapsulates, load/unload rate of the storage, and cost of the installation were determined, and experiments were performed following the design of experiments strategy. The statistical analysis showed that the effects with significant influence in the solidification process are the thickness of the encapsulation, the inlet temperature of the air, the air flow, and the interaction thickness x temperature. For the melting process the same holds, but the inlet air temperature had a higher influence than the thickness of the encapsulation. With the empirical model developed in this work, a real free-cooling system was designed and economically evaluated. (author)

  10. Thermal analysis of a building brick containing phase change material

    Energy Technology Data Exchange (ETDEWEB)

    Alawadhi, E.M. [Kuwait Univ., Safat (Kuwait). Dept. of Mechanical Engineering

    2008-07-01

    This paper presents the thermal analysis of a building brick containing phase change material (PCM) to be used in hot climates. The objective of using the PCM is to utilize its high latent heat of fusion to reduce the heat gain by absorbing the heat in the bricks through the melting process before it reaches the indoor space. The considered model consists of bricks with cylindrical holes filled with PCM. The problem is solved in a two-dimensional space using the finite element method. The thermal effectiveness of the proposed brick-PCM system is evaluated by comparing the heat flux at the indoor surface to a wall without the PCM during typical working hours. A paramedic study is conducted to assess the effect of different design parameters, such as the PCM's quantity, type, and location in the brick. The results indicate that the heat gain is significantly reduced when the PCM is incorporated into the brick, and increasing the quantity of the PCM has a positive effect. PCM cylinders located at the centerline of the bricks shows the best performance. (author)

  11. Continued Water-Based Phase Change Material Heat Exchanger Development

    Science.gov (United States)

    Hansen, Scott W.; Sheth, Rubik B.; Poynot, Joe; Giglio, Tony; Ungar, Gene K.

    2015-01-01

    In a cyclical heat load environment such as low Lunar orbit, a spacecraft's radiators are not sized to meet the full heat rejection demands. Traditionally, a supplemental heat rejection device (SHReD) such as an evaporator or sublimator is used to act as a "topper" to meet the additional heat rejection demands. Utilizing a Phase Change Material (PCM) heat exchanger (HX) as a SHReD provides an attractive alternative to evaporators and sublimators as PCM HX's do not use a consumable, thereby leading to reduced launch mass and volume requirements. In continued pursuit of water PCM HX development two full-scale, Orion sized water-based PCM HX's were constructed by Mezzo Technologies. These HX's were designed by applying prior research on freeze front propagation to a full-scale design. Design options considered included bladder restraint and clamping mechanisms, bladder manufacturing, tube patterns, fill/drain methods, manifold dimensions, weight optimization, and midplate designs. Two units, Units A and B, were constructed and differed only in their midplate design. Both units failed multiple times during testing. This report highlights learning outcomes from these tests and are applied to a final sub-scale PCM HX which is slated to be tested on the ISS in early 2017.

  12. Experimental Investigation of Ice Phase Change Material Heat Exchangers

    Science.gov (United States)

    Leimkuehler, Thomas O.; Stephan, Ryan A.

    2012-01-01

    Phase change materials (PCM) may be useful for spacecraft thermal control systems that involve cyclical heat loads or cyclical thermal environments. Thermal energy can be stored in the PCM during peak heat loads or in adverse thermal environments. The stored thermal energy can then be released later during minimum heat loads or in more favorable thermal environments. This can result in a decreased turndown ratio for the radiator and a reduced system mass. The use of water as a PCM rather than the more traditional paraffin wax has the potential for significant mass reduction since the latent heat of formation of water is approximately 70% greater than that of wax. One of the potential drawbacks of using ice as a PCM is its potential to rupture its container as water expands upon freezing. In order to develop a space qualified ice PCM heat exchanger, failure mechanisms must first be understood. Therefore, a methodical experimental investigation has been undertaken to demonstrate and document specific failure mechanisms due to ice expansion in the PCM. A number of ice PCM heat exchangers were fabricated and tested. Additionally, methods for controlling void location in order to reduce the risk of damage due to ice expansion were investigated. This paper presents an overview of the results of this investigation from the past three years.

  13. Nano-scale spinning detonation in condensed phase energetic materials

    Science.gov (United States)

    Zhakhovsky, Vasily; Budzevich, Mikalai; Landerville, Aaron; White, Carter; Oleynik, Ivan

    2013-06-01

    Single- and multi-headed spinning detonation waves are observed in molecular dynamics simulations of a condensed phase detonation of an energetic material (EM) confined in round tubes of different radii. The EM is modeled using a modified AB Reactive Empirical Bond Order potential. The thermochemistry and reactive equation of state are varied by adjusting the barrier height for the exothermic reaction AB +B --> A +BB. This allows us to study the evolution of the detonation-wave structure as a function of physico-chemical properties of the AB explosive. The detonation wave is found to exhibit a pulsating planar front in a tube of 8 nm radius, which later collapses due to the development of longitudinal perturbations. Upon increase of the tube's radius to 16 nm, the detonation wave structure is stabilized through the development of a single-headed spinning detonation. The spinning detonation displays a four-wave configuration, including incident, oblique, transverse, and contact shock waves. The contact shock generated by a contact discontinuity is observed for the first time in our MD simulations. A multi-headed turbulent-like detonation structure develops within tubes of larger radii, and exhibit features similar to those observed in gases.

  14. 48 CFR 52.227-20 - Rights in Data-SBIR Program.

    Science.gov (United States)

    2010-10-01

    ... Data—SBIR Program (DEC 2007) (a) Definitions. As used in this clause— Computer database or database... financial, administrative, cost or pricing or management information. Form, fit, and function data means... include computer software or financial, administrative, cost or pricing, or management data or...

  15. 78 FR 11745 - Small Business Size Regulations, Small Business Innovation Research (SBIR) Program and Small...

    Science.gov (United States)

    2013-02-20

    ... / Wednesday, February 20, 2013 / Rules and Regulations#0;#0; ] SMALL BUSINESS ADMINISTRATION 13 CFR Part 121 RIN 3245-AG46 Small Business Size Regulations, Small Business Innovation Research (SBIR) Program and Small Business Technology Transfer (STTR) Program; Correction AGENCY: U.S. Small Business...

  16. 13 CFR 121.701 - What SBIR programs are subject to size determinations?

    Science.gov (United States)

    2010-01-01

    ... design, development, and improvement of prototypes and new processes to meet specific requirements. ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false What SBIR programs are subject to size determinations? 121.701 Section 121.701 Business Credit and Assistance SMALL BUSINESS...

  17. Funding Opportunities Available for Innovative SBIR Development - Office of Cancer Clinical Proteomics Research

    Science.gov (United States)

    Does your small business need early-stage financing to take its cancer research to the next level? The National Cancer Institute Small Business Innovation Research (NCI SBIR) Development Center has released $5 million for new contract funding opportunities to support cancer research and technology development in key emerging areas of need.

  18. 40 CFR 227.32 - Liquid, suspended particulate, and solid phases of a material.

    Science.gov (United States)

    2010-07-01

    ... MATERIALS Definitions § 227.32 Liquid, suspended particulate, and solid phases of a material. (a) For the... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Liquid, suspended particulate, and solid phases of a material. 227.32 Section 227.32 Protection of Environment ENVIRONMENTAL...

  19. Manufacture of Novel Cryogenic Thermal Protection Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Materials Technology, Inc (AMTI) responds to the NASA SBIR solicitation X8 "Space Cryogenic Systems" under subtopic X8.01, "Cryogenic Fluid Transfer and...

  20. Low Cost, Lightweight, Multifunctional Structural Shielding Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR involves the development of a lightweight innovative material for use as structure and radiation shielding in one. APS has assembled a uniquely qualified...

  1. Phase-change material as a thermal storage media

    Energy Technology Data Exchange (ETDEWEB)

    El Chazly, Nihad M; Khattab, Nagwa M [Dokki, Cairo (Egypt)

    2000-07-01

    Heat storage based on the sensible heating of media such as water, rock and earth represent the first generation of solar energy storage subsystems and technology for their utilization. However, recently the heat storage based on the latent heat associated with a change in phase of a material offers many advantages over sensible heat storage. The most important characteristic of such a subsystem is its a sufficient storage capacity. An idealized model visualizing a thermal capacitor using a phase change material is constructed and subjected to simulated solar system environmental conditions. The proposed model is of a flat plate geometry consisting of two panels compartments forming the body of the capacitor containing the paraffin, leaving at their inner surfaces a thin passage allowing the water flow. The whole structure was assumed to be insulated to minimize heat loss. An analysis of the model is conducted using Goodman technique to generate data about the temperature distribution, the melt thickness, and the heat stored in the PCM under conditions of: ( i ) constant mass flow rate tests for various water inlet temperatures and ( ii ) constant water inlet temperature for various mass flow rate. A FORTRAN computer program was constructed to perform the analysis. It was found the water outlet temperature increases with time until it becomes nearly equals to the inlet temperature. Increasing the mass flow rate for a given inlet temperature, decreases the time required for outlet temperature to reach a given value. Increasing inlet temperature for a given mass flow rate gives a very rapid decrease in the time required for the outlet water temperature to reach a given value. Instantaneous rate of heat storage was determined from the inlet-to- exit temperature differential and measured flow rate. This rate was then integrated numerically to determine the cumulative total energy stored as a function of time. It was found that the instantaneous rate of heat storage

  2. Balancing innovation with commercialization in NASA's Science Mission Directorate SBIR Program

    Science.gov (United States)

    Terrile, R. J.; Jackson, B. L.

    The NASA Science Mission Directorate (SMD) administers a portion of the Small Business Innovative Research (SBIR) Program. One of the challenges of administrating this program is to balance the need to foster innovation in small businesses and the need to demonstrate commercialization by infusion into NASA. Because of the often risky nature of innovation, SBIR programs will tend to drift into a status that rewards proposals that promise to deliver a product that is exactly what was specified in the call. This often will satisfy the metric of providing a clear demonstration of infusion and thus also providing a publishable success story. However, another goal of the SBIR program is to foster innovation as a national asset. Even though data from commercially successful SMD SBIR tasks indicate a higher value for less innovative efforts, there are programmatic and national reasons to balance the program toward risking a portion of the portfolio on higher innovation tasks. Establishing this balance is made difficult because there is a reward metric for successful infusion and commercialization, but none for successful innovation. In general, the ultimate infusion and commercialization of innovative solutions has a lower probability than implementation of established ideas, but they can also have a much higher return on investment. If innovative ideas are valued and solicited in the SBIR program, then NASA technology requirements need to be specified in a way that defines the problem and possible solution, but will also allow for different approaches and unconventional methods. It may also be necessary to establish a guideline to risk a percentage of awards on these innovations.

  3. Study of improving the thermal response of a construction material containing a phase change material

    Science.gov (United States)

    Laaouatni, A.; Martaj, N.; Bennacer, R.; Elomari, M.; El Ganaoui, M.

    2016-09-01

    The use of phase change materials (PCMs) for improving the thermal comfort in buildings has become an attractive application. This solution contributes to increasing the thermal inertia of the building envelope and reducing power consumption. A building element filled with a PCM and equipped with ventilation tubes is proposed, both for increasing inertia and contributing to refreshing building envelope. A numerical simulation is conducted by the finite element method in COMSOL Multiphysics, which aims to test the thermal behaviour of the developed solution. An experimental study is carried out on a concrete block containing a PCM with ventilation tubes. The objective is to see the effect of PCM coupled with ventilation on increasing the inertia of the block. The results show the ability of this new solution to ensure an important thermal inertia of a building.

  4. Studies of cluster-assembled materials: From gas phase to condensed phase

    Science.gov (United States)

    Gao, Lin

    . After being mass gated in a reflectron equipped time-of-flight mass spectrometer (TOF-MS) and deposited onto TEM grids, the resultant specimens can be loaded onto high-resolution TEM investigation via electron diffraction. In conclusion, soft-landing of mass selected clusters has been shown to be a successful approach to obtain structural information on Zr-Met-Car cluster-assembled materials collected from the gas phase. TEM images indicate the richness of the morphologies associated with these cluster crystals. However, passivation methods are expected to be examined further to overcome the limited stabilities of these novel clusters. From this initial study, it's shown the promising opportunity to study other Met-Cars species and more cluster-based materials. Experimental results of reactions run with a solvothermal synthesis method obtained while searching for new Zr-C cluster assembled materials, are reported. One unexpected product in single crystal form was isolated and tentatively identified by X-ray diffraction to be [Zr6i O(OH)O12·2(Bu)4], with space group P2 1/n and lattice parameters of a = 12.44 A, b = 22.06 A, c = 18.40 A, alpha = 90°, beta = 105°, gamma = 90°, V = 4875 A3 and R 1 = 3.15% for the total observed data (I ≥ 2 sigma I) and oR2 = 2.82%. This novel hexanuclear Zr(IV)-oxo-hydroxide cluster anion may be the first member in polyoxometalates class with metal atoms from the IVB group and having Oh symmetry. Alternatively, it may be the first member in {[(Zr6Z)X 12]X6}m- class with halides replaced by oxo- and hydroxyl groups and with an increased oxidation state of Zr. It is predicted to bear application potentials directed by both families. This work could suggest a direction in which the preparation of Zr-C cluster-assembled materials in a liquid environment may be eventually fulfilled. 1,3-Bis(diethylphosphino)propane (depp) protected small gold clusters are studied via multiple techniques, including Electrospray Ionization Mass Spectrometry

  5. Ductile-Phase-Toughened Tungsten for Plasma-Facing Materials

    Science.gov (United States)

    Cunningham, Kevin Hawkins

    A variety of processing approaches were employed to fabricate ductile-phase-toughened (DPT) tungsten (W) composites. Mechanical testing and analytical modeling were used to guide composite development. This work provides a basis for further development of W composites to be used in structural divertor components of future fusion reactors. W wire was tested in tension, showing significant ductility and strength. Coatings of copper (Cu) or tungsten carbide (WC) were applied to the W wire via electrodeposition and carburization, respectively. Composites were fabricated using spark plasma sintering (SPS) to consolidate W powders together with each type of coated W wire. DPT behavior, e.g. crack arrest and crack bridging, was not observed in three-point bend testing of the sintered composites. A laminate was fabricated by hot pressing W and Cu foils together with W wires, and subsequently tested in tension. This laminate was bonded via hot pressing to thick W plate as a reinforcing layer, and the composite was tested in three-point bending. Crack arrest was observed along with some fiber pullout, but significant transverse cracking in the W plate confounded further fracture toughness analysis. The fracture toughness of thin W plate was measured in three-point bending. W plates were brazed with Cu foils to form a laminate. Crack arrest and crack bridging were observed in three-point bend tests of the laminate, and fracture resistance curves were successfully calculated for this DPT composite. An analytical model of crack bridging was developed using the basis described by Chao in previous work by the group. The model uses the specimen geometry, matrix properties, and the stress-displacement function of a ductile reinforcement ("bridging law") to calculate the fracture resistance curve (R-curve) and load-displacement curve (P-D curve) for any test specimen geometry. The code was also implemented to estimate the bridging law of an arbitrary composite using R-curve data

  6. The MAX Phases: Unique New Carbide and Nitride Materials

    Science.gov (United States)

    Barsoum, Michel W.; El-Raghy, Tamer

    2001-07-01

    One of the major challenges in engineering is the need for versatile materials to serve rapidly developing technologies. For durability and high performance in extreme environments, metals seem ideal: They are electrical and thermal conductors, damage-tolerant and able to withstand high temperatures. Ceramics offer a different set of qualities, being elastically rigid, lightweight, resistant to fatigue and oxidation and even better at enduring high temperatures. An ideal high-performance structural material for, say, jet engines would have all these qualities—and a new class of materials being explored by the authors meets the test. They are fabricating layered materials combining transition metals, carbon or nitrogen and silicon or a related material. The materials form a new class of solids, the nanolaminates, which exhibits new physics along with unusual machinability.

  7. Modeling of Impact Properties of Auxetic Materials: Phase 1

    Science.gov (United States)

    2013-08-01

    underlying metal substrate from impact damage will be determined, and compared to the effect of solid polymer coatings (containing no honeycomb shaped air...higher indentation resistance, higher fracture toughness and greater resistance to impact damage . These unique features of the auxetic materials make... Elastoplasticity of auxetic materials, Computational Material Science, in press. [24] Horrigan, E.J., Smith, C.W., Scarpa, F.L., Gaspar, N., Javadi, A.A

  8. Integrated Planar Lightwave Circuits for UV Generation and Phase Modulation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I effort proposes to establish the feasibility of developing a UV Planar Lightwave Circuit (PLC); a compact, highly efficient, waveguide-based...

  9. Waveguide Phase Modulator for Integrated Planar Lightwave Circuits in KTP Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase II effort proposes the development and integration of a Planar Lightwave Circuit (PLC) into an all fiber-based seed laser system used in high...

  10. The use of lipids as phase change materials for thermal energy storage

    Science.gov (United States)

    Phase change materials (PCMs) are substances capable of absorbing and releasing large 2 amounts of thermal energy (heat or cold) as latent heat over constant temperature as they 3 undergo a change in state of matter (phase transition), commonly, between solid and 4 liquid phases. Since the late 194...

  11. Phase relationships and materials design in the Ln-Si-Al-O-N system

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Subsolidus phase relationships in the system Ln2O3-Si3N4-AlN-Al2O3, where Ln represents Nd, Sm and Dy, were summarized, with emphasis on the region involving α-sialon, β-sialon and AlN-polytypoid phases. This information is further used in designing the compatible matrix phases of sialon materials with desirable properties. Examples were provided to illustrate the advantage of such a basic approach to materials design.

  12. Microchannel plate special nuclear materials sensor

    Energy Technology Data Exchange (ETDEWEB)

    Feller, W.B., E-mail: bfeller@novascientific.com [Nova Scientific Inc., 10 Picker Road, Sturbridge, MA 01566 (United States); White, P.L.; White, P.B. [Nova Scientific Inc., 10 Picker Road, Sturbridge, MA 01566 (United States); Siegmund, O.H.W.; Martin, A.P.; Vallerga, J.V. [Sensor Sciences, 3333 Vincent Road, Pleasant Hill, CA 94523 (United States)

    2011-10-01

    Nova Scientific Inc., is developing for the Domestic Nuclear Detection Office (DNDO SBIR no. HSHQDC-08-C-00190), a solid-state, high-efficiency neutron detection alternative to {sup 3}He gas tubes, using neutron-sensitive microchannel plates (MCPs) containing {sup 10}B and/or Gd. This work directly supports DNDO development of technologies designed to detect and interdict nuclear weapons or illicit nuclear materials. Neutron-sensitized MCPs have been shown theoretically and more recently experimentally, to be capable of thermal neutron detection efficiencies equivalent to {sup 3}He gas tubes. Although typical solid-state neutron detectors typically have an intrinsic gamma sensitivity orders of magnitude higher than that of {sup 3}He gas detectors, we dramatically reduce gamma sensitivity by combining a novel electronic coincidence rejection scheme, employing a separate but enveloping gamma scintillator. This has already resulted in a measured gamma rejection ratio equal to a small {sup 3}He tube, without in principle sacrificing neutron detection efficiency. Ongoing improvements to the MCP performance as well as the coincidence counting geometry will be described. Repeated testing and validation with a {sup 252}Cf source has been underway throughout the Phase II SBIR program, with ongoing comparisons to a small commercial {sup 3}He gas tube. Finally, further component improvements and efforts toward integration maturity are underway, with the goal of establishing functional prototypes for SNM field testing.

  13. Raman Mapping for the Investigation of Nano-phased Materials

    Science.gov (United States)

    Gouadec, G.; Bellot-Gurlet, L.; Baron, D.; Colomban, Ph.

    Nanosized and nanophased materials exhibit special properties. First they offer a good compromise between the high density of chemical bonds by unit volume, needed for good mechanical properties and the homogeneity of amorphous materials that prevents crack initiation. Second, interfaces are in very high concentration and they have a strong influence on many electrical and redox properties. The analysis of nanophased, low crystallinity materials is not straigtforward. The recording of Raman spectra with a geometric resolution close to 0.5 \\upmu {text{ m}^3} and the deep understanding of the Raman signature allow to locate the different nanophases and to predict the properties of the material. Case studies are discussed: advanced polymer fibres, ceramic fibres and composites, textured piezoelectric ceramics and corroded (ancient) steel.

  14. Nature of phase transitions in crystalline and amorphous GeTe-Sb2Te3 phase change materials.

    Science.gov (United States)

    Kalkan, B; Sen, S; Clark, S M

    2011-09-28

    The thermodynamic nature of phase stabilities and transformations are investigated in crystalline and amorphous Ge(1)Sb(2)Te(4) (GST124) phase change materials as a function of pressure and temperature using high-resolution synchrotron x-ray diffraction in a diamond anvil cell. The phase transformation sequences upon compression, for cubic and hexagonal GST124 phases are found to be: cubic → amorphous → orthorhombic → bcc and hexagonal → orthorhombic → bcc. The Clapeyron slopes for melting of the hexagonal and bcc phases are negative and positive, respectively, resulting in a pressure dependent minimum in the liquidus. When taken together, the phase equilibria relations are consistent with the presence of polyamorphism in this system with the as-deposited amorphous GST phase being the low entropy low-density amorphous phase and the laser melt-quenched and high-pressure amorphized GST being the high entropy high-density amorphous phase. The metastable phase boundary between these two polyamorphic phases is expected to have a negative Clapeyron slope. © 2011 American Institute of Physics

  15. Two-phase materials for high-temperature service

    CSIR Research Space (South Africa)

    Nabarro, FRN

    2000-09-01

    Full Text Available viewed on the scale of the precipitate particles The structure consists of cubes of the g0 phase, an ordered L12 structure based on Ni3Al, stacked in a simple cubic array in a matrix of g, a disordered face- centred cubic lattice, also nickel-based. The g... occurs in <110> directions on {111} planes. In the disordered g phase, with lattice parameter a, the repeat distance, which is the Bur- gers vector of a single dislocation, is 1/2 a <110>. In the ordered g0 structure, the repeat distance is a <110>. If a...

  16. Analysis of writing and erasing behaviours in phase change materials

    Energy Technology Data Exchange (ETDEWEB)

    Hyot, B. E-mail: bhyot@cea.fr; Poupinet, L.; Gehanno, V.; Desre, P.J

    2002-09-01

    An understanding of the process involved in writing and erasing of phase-change optical recording media is vital to the development of new, and the improvement of existing, products. The present work investigates both experimental and theoretical laser-induced fast structural transformations of GeSbTe thin films. Optical and microstructural changes are correlated using both a static tester and transmission electron microscopy. In the second part of this paper we try to elucidate the physics underlying the amorphous-to-crystalline phase transformation under short-pulse laser excitation. Both thermal and thermodynamical behaviours must be taken into account to illustrate real processes.

  17. Design of materials with extreme thermal expansion using a three-phase topology optimization method

    DEFF Research Database (Denmark)

    Sigmund, Ole; Torquato, S.

    1997-01-01

    We show how composites with extremal or unusual thermal expansion coefficients can be designed using a numerical topology optimization method. The composites are composed of two different material phases and void. The optimization method is illustrated by designing materials having maximum thermal...... expansion, zero thermal expansion, and negative thermal expansion. Assuming linear elasticity, it is shown that materials with effective negative thermal expansion coefficients can be obtained by mixing two phases with positive thermal expansion coefficients and void. We also show...

  18. Robust Engineered Thermal Control Material Systems for Crew Exploration Vehicle (CEV) and Prometheus Needs Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This innovative SBIR Phase II proposal plans to develop new multifunctional high temperature capable TCMS technologies based on the identified needs for the thermal...

  19. NASA's Management and Utilization of the Small Business Innovative Research (SBIR) Program

    Science.gov (United States)

    Mexcur, Winfield Paul

    2003-01-01

    The United Space Congress established the SBIR program in 1982 for the following purposes: ( 1) Stimulate technological innovation (2) Increase private-sector commercialization derived from federal R&D (3) Use small business to meet federal R&D needs (4) Foster and encourage participation by disadvantaged persons and women in technological innovation The STTR program was established in 1992 with the additional requirement of having a small business partner with a research institution (usually a university) for the purpose of transferring intellectual property from the research institution to the small business concern for enabling a government technical need and furthering the technological development for the purpose of developing commercial products. The government of Japan has established a program that models portions of the U.S. SBIR and STTR programs. They are very interested in how NASA has been so successful in fulfilling the Congressional objectives of these programs. In particular, they want to understand the management practices and incentives that are provided to enable partnerships between business enterprises, academia and government. The speech will also focus on some of the many successful technologies (on a conceptual level) that have been developed through NASA s SBIR and STTR programs and mechanisms used to promote cooperation between small businesses, large businesses, academia and government agencies within the United States. The speech is on a conceptual level, focusing on U.S. and NASA policies and management implementation practices. No enabling technical discussion will be held.

  20. NASA's Management and Utilization of the Small Business Innovative Research (SBIR) Program

    Science.gov (United States)

    Mexcur, Winfield Paul

    2003-01-01

    The United Space Congress established the SBIR program in 1982 for the following purposes: ( 1) Stimulate technological innovation (2) Increase private-sector commercialization derived from federal R&D (3) Use small business to meet federal R&D needs (4) Foster and encourage participation by disadvantaged persons and women in technological innovation The STTR program was established in 1992 with the additional requirement of having a small business partner with a research institution (usually a university) for the purpose of transferring intellectual property from the research institution to the small business concern for enabling a government technical need and furthering the technological development for the purpose of developing commercial products. The government of Japan has established a program that models portions of the U.S. SBIR and STTR programs. They are very interested in how NASA has been so successful in fulfilling the Congressional objectives of these programs. In particular, they want to understand the management practices and incentives that are provided to enable partnerships between business enterprises, academia and government. The speech will also focus on some of the many successful technologies (on a conceptual level) that have been developed through NASA s SBIR and STTR programs and mechanisms used to promote cooperation between small businesses, large businesses, academia and government agencies within the United States. The speech is on a conceptual level, focusing on U.S. and NASA policies and management implementation practices. No enabling technical discussion will be held.

  1. Tunable ferroelectric meta-material phase shifter embedded inside low temperature co-fired ceramics (LTCC)

    Science.gov (United States)

    Tork, Hossam S.

    This dissertation describes electrically tunable microwave devices utilizing low temperature co-fired ceramics (LTCC) and thick film via filled with the ferroelectric materials barium strontium titanate (BST) and barium zirconate titanate (BZT). Tunable ferroelectric capacitors, zero meta-material phase shifters, and tunable meta-material phase shifters are presented. Microwave phase shifters have many applications in microwave devices. They are essential components for active and passive phased array antennas and their most common use is in scanning phased array antennas. They are used in synthetic aperture radars (SAR), low earth orbit (LEO) communication satellites, collision warning radars, and intelligent vehicle highway systems (IVHS), in addition to various other applications. Tunable ferroelectric materials have been investigated, since they offer the possibility of lowering the total cost of phased arrays. Two of the most promising ferroelectric materials in microwave applications are BST and BZT. The proposed design and implementation in this research introduce new types of tunable meta-material phase shifters embedded inside LTCC, which use BST and BZT as capacitive tunable dielectric material controlled by changing the applied voltage. This phase shifter has the advantages of meta-material structures, which produce little phase error and compensation while having the simultaneous advantage of using LTCC technology for embedding passive components that improve signal integrity (several signal lines, power planes, and ground planes) by using different processes like via filling, screen printing, laminating and firing that can be produced in compact sizes at a low cost. The via filling technique was used to build tunable BST, BZT ferroelectric material capacitors to control phase shift. Finally, The use of the proposed ferroelectric meta-material phase shifter improves phase shifter performance by reducing insertion loss in both transmitting and receiving

  2. Promising Results from Three NASA SBIR Solar Array Technology Development Programs

    Science.gov (United States)

    Eskenazi, Mike; White, Steve; Spence, Brian; Douglas, Mark; Glick, Mike; Pavlick, Ariel; Murphy, David; O'Neill, Mark; McDanal, A. J.; Piszczor, Michael

    2005-01-01

    Results from three NASA SBIR solar array technology programs are presented. The programs discussed are: 1) Thin Film Photovoltaic UltraFlex Solar Array; 2) Low Cost/Mass Electrostatically Clean Solar Array (ESCA); and 3) Stretched Lens Array SquareRigger (SLASR). The purpose of the Thin Film UltraFlex (TFUF) Program is to mature and validate the use of advanced flexible thin film photovoltaics blankets as the electrical subsystem element within an UltraFlex solar array structural system. In this program operational prototype flexible array segments, using United Solar amorphous silicon cells, are being manufactured and tested for the flight qualified UltraFlex structure. In addition, large size (e.g. 10 kW GEO) TFUF wing systems are being designed and analyzed. Thermal cycle and electrical test and analysis results from the TFUF program are presented. The purpose of the second program entitled, Low Cost/Mass Electrostatically Clean Solar Array (ESCA) System, is to develop an Electrostatically Clean Solar Array meeting NASA s design requirements and ready this technology for commercialization and use on the NASA MMS and GED missions. The ESCA designs developed use flight proven materials and processes to create a ESCA system that yields low cost, low mass, high reliability, high power density, and is adaptable to any cell type and coverglass thickness. All program objectives, which included developing specifications, creating ESCA concepts, concept analysis and trade studies, producing detailed designs of the most promising ESCA treatments, manufacturing ESCA demonstration panels, and LEO (2,000 cycles) and GEO (1,350 cycles) thermal cycling testing of the down-selected designs were successfully achieved. The purpose of the third program entitled, "High Power Platform for the Stretched Lens Array," is to develop an extremely lightweight, high efficiency, high power, high voltage, and low stowed volume solar array suitable for very high power (multi-kW to MW

  3. Research data supporting "Determining pressure-temperature phase diagrams of materials"

    OpenAIRE

    Baldock, Robert J.N.; Partay, Livia B.; Bartok, Albert P.; Payne, Michael C.; Csanyi, Gabor

    2016-01-01

    Pressure-temperature phase diagrams of the Lennard-Jones system, aluminium and nickel titanium as reported in the paper "Determining pressure-temperature phase diagrams of materials", together with example nested sampling output for aluminium and nickel titanium calculations. This research data supports “Determining pressure-temperature phase diagrams of materials” which has been published in “Physical Review B”. Research data supporting “Determining pressure-temperature phase diagrams...

  4. ZnSe-material phase mask applied to athermalization of infrared imaging systems.

    Science.gov (United States)

    Feng, Bin; Shi, Zelin; Xu, Baoshu; Zhang, Chengshuo; Zhang, Xiaodong

    2016-07-20

    This paper reports a ZnSe-material phase mask that is applied to athermalization of a conventional infrared imaging system. Its principle, design, manufacture, measurement, and performance validation are successively discussed. This paper concludes that a ZnSe-material phase mask has a permissible manufacturing error 2.14 times as large as a Ge-material phase mask. By constructing and solving an optimization problem, the ZnSe-material phase mask is optimally designed. The optimal phase mask is manufactured and measured with a form manufacturing error of 1.370 μm and a surface roughness value of 9.926 nm. Experiments prove that the wavefront coding athermalized longwave infrared (LWIR) imaging system works well over the temperature range from -40°C to +60°C.

  5. The role of vacancies and local distortions in the design of new phase-change materials.

    Science.gov (United States)

    Wuttig, Matthias; Lüsebrink, Daniel; Wamwangi, Daniel; Wełnic, Wojciech; Gillessen, Michael; Dronskowski, Richard

    2007-02-01

    Phase-change materials are of tremendous technological importance ranging from optical data storage to electronic memories. Despite this interest, many fundamental properties of phase-change materials, such as the role of vacancies, remain poorly understood. 'GeSbTe'-based phase-change materials contain vacancy concentrations around 10% in their metastable crystalline structure. By using density-functional theory, the origin of these vacancies has been clarified and we show that the most stable crystalline phases with rocksalt-like structures are characterized by large vacancy concentrations and local distortions. The ease by which vacancies are formed is explained by the need to annihilate energetically unfavourable antibonding Ge-Te and Sb-Te interactions in the highest occupied bands. Understanding how the interplay between vacancies and local distortions lowers the total energy helps to design novel phase-change materials as evidenced by new experimental data.

  6. Emission energy control of semiconductor quantum dots using phase change material

    Science.gov (United States)

    Kanazawa, Shohei; Sato, Yu; Yamamura, Ariyoshi; Saiki, Toshiharu

    2015-03-01

    Semiconductor quantum dots have paid much attention as it is a promising candidate for quantum, optical devices, such as quantum computer and quantum dot laser. We propose a local emission energy control method of semiconductor quantum dots using applying strain by volume expansion of phase change material. Phase change material can change its phase crystalline to amorphous, and the volume expand by its phase change. This method can control energy shift direction and amount by amorphous religion and depth. Using this method, we matched emission energy of two InAs/InP quantum dots. This achievement can connect to observing superradiance phenomenon and quantum dot coupling effect.

  7. Materials for Spectral Hole Burning Research. Phase 1

    Science.gov (United States)

    1994-03-22

    furnace causing the furnace to melt. This problem occurs occassionally in the growth of other crystals . 4 Figure 2 Verneuil (Flame Fusion) I...SB1 1 ,1 11 ) Ia ght L tion r .9,Gi stributin uniitd Approved for public release; 13. ABSTRACT (Maximum 200 wordt)I Work on the crystal growth and...multiple hosts. In the work on this program, Scientific Materials Corporation grew crystals of the following compositions. Dopant Growth Method 1.0

  8. Temperature-driven topological quantum phase transitions in a phase-change material Ge2Sb2Te5

    Science.gov (United States)

    Eremeev, S. V.; Rusinov, I. P.; Echenique, P. M.; Chulkov, E. V.

    2016-12-01

    The Ge2Sb2Te5 is a phase-change material widely used in optical memory devices and is a leading candidate for next generation non-volatile random access memory devices which are key elements of various electronics and portable systems. Despite the compound is under intense investigation its electronic structure is currently not fully understood. The present work sheds new light on the electronic structure of the Ge2Sb2Te5 crystalline phases. We demonstrate by predicting from first-principles calculations that stable crystal structures of Ge2Sb2Te5 possess different topological quantum phases: a topological insulator phase is realized in low-temperature structure and Weyl semimetal phase is a characteristic of the high-temperature structure. Since the structural phase transitions are caused by the temperature the switching between different topologically non-trivial phases can be driven by variation of the temperature. The obtained results reveal the rich physics of the Ge2Sb2Te5 compound and open previously unexplored possibility for spintronics applications of this material, substantially expanding its application potential.

  9. Thermal performance of a pcm [phase change material] storage unit

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, K.A.R.; Goncalves, M.M. [Depto de Engenharia Termica e de Fluidos-FEM-UNICAMP (Brazil)

    1999-10-01

    This paper presents a two-dimensional model for the phase change, conduction based heat transfer problem around a tube immersed in the pcm. The energy equation is written in the enthalpy form, and the heat and flow problems are coupled by an energy balance on the fluid element flowing inside the tube. The numerical solution is based upon the average control volume technique and the ADI finite difference representation. The results obtained show the effects of the variation of the ratio of the radius of the inner to the outer tube, Biot number, Stefan number and the working fluid inlet temperature on the solidified mass fraction, NTU and effectiveness. (author)

  10. Defense Small Business Innovation Research Program (SBIR) FY 1983.

    Science.gov (United States)

    1983-05-31

    that within a repeater module, the battery would be the most expensive component. Present technology suggests the use of a lithium thionyl chloride ...mercial lithium -sulfur dioxide or lithium - thionyl chloride cells, and propose a change in the materials, configuration, production process, or...rechargeable lithium batteries . Intercalates wlll be described in terms of chemical content, structure, etc., in quantities of 100 grams each. ." i. Electron

  11. Materials Design of Microstructure in Grain Boundary and Second Phase Particles

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A concept of microstructure design for materials or materials microstructure engineering is proposed. The argument was suggested based on literature review and some our new research work on second phase strengthening mechanisms and mechanical property modeling of a particulate reinforced metal matrix composite. Due to development of computer technology, it is possible now for us to establish the relationship between microstructures and properties systematically and quantitatively by analytical and numerical modeling in the research scope of computerization materials. Discussions and examples on intellectual optimization of microstructure are presented on two aspects:grain boundary engineering and optimal geometry of particulate reinforcements in two-phase materials.

  12. Thermophysical properties and behavioral characteristics of phase-change materials

    Energy Technology Data Exchange (ETDEWEB)

    Cantor, S

    1977-01-01

    The primary and near-term objective of the project is to compile a handbook of compounds and mixtures that melt in the range of 90 to 250/sup 0/C and which are suitable for isothermal heat storage. Organic compounds have been screened according to bulk price, thermal stability, and safety. Compounds were selected for further consideration if they cost less than $1.10/kg and if encyclopedia articles or handbooks indicated that they were reasonably stable chemically and were not toxic or otherwise hazardous. Of seven compounds thus selected, four (urea, phthalimide, adipic acid, phthalic anhydride) have been examined by DSC and other methods. The differential scanning calorimeter was used with two fairly well-characterized PCM's to test its applicability for rapidly evaluating thermal decomposition and supercooling. With Na/sub 2/SO/sub 4/ . 10H/sub 2/O, DSC data indicated (a) decrease in heat of transition with thermal cycling, and (b) considerable supercooling; with 3 to 6 percent borax added, supercooling was greatly lessened but not entirely eliminated. Measurements with paraffin wax showed that this material does not supercool nor does it degrade in thermal performance with cycling. The DSC results with these two materials confirmed (and extended) thermal performance characteristics obtained by other means. However, studies of supercooling in urea and in phthalimide suggested that DSC techniques may magnify the extent of supercooling at elevated temperatures.

  13. Microencapsulation of butyl stearate as a phase change material by interfacial polycondensation in a polyurea system

    Energy Technology Data Exchange (ETDEWEB)

    Chen Liang [College of Material Science and Engineering, Nanjing University of Technology, Nanjing 210009 (China)], E-mail: doseng_1982@hotmail.com; Xu Lingling; Shang Hongbo; Zhang Zhibin [College of Material Science and Engineering, Nanjing University of Technology, Nanjing 210009 (China)

    2009-03-15

    For the last 20 years, microencapsulated phase change materials (MicroPCMs), which combine microencapsulation technology and phase change material, have been attracted more and more interest. By overcoming some limitations of the PCMs, the MicroPCMs improve the efficiency of PCMs and make it possible to apply PCMs in many areas. In this experiment, polyurea microcapsules containing phase change materials were prepared using interfacial polycondensation method. Toluene-2,4-diisocyanate (TDI) and ethylenediamine (EDA) were chosen as monomers. Butyl stearate was employed as a core material. The MicroPCMs' properties have been characterized by dry weight analysis, differential scanning calorimetry, Fourier transform IR spectra analysis and optical microscopy. The results show that the MicroPCMs were synthesized successfully and that, the phase change temperature was about 29 deg. C, the latent heat of fusion was about 80 J g{sup -1}, the particle diameter was 20-35 {mu}m.

  14. Microencapsulation of butyl stearate as a phase change material by interfacial polycondensation in a polyurea system

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Chen; Lingling, Xu; Hongbo, Shang; Zhibin, Zhang [College of Material Science and Engineering, Nanjing University of Technology, Nanjing 210009 (China)

    2009-03-15

    For the last 20 years, microencapsulated phase change materials (MicroPCMs), which combine microencapsulation technology and phase change material, have been attracted more and more interest. By overcoming some limitations of the PCMs, the MicroPCMs improve the efficiency of PCMs and make it possible to apply PCMs in many areas. In this experiment, polyurea microcapsules containing phase change materials were prepared using interfacial polycondensation method. Toluene-2,4-diisocyanate (TDI) and ethylenediamine (EDA) were chosen as monomers. Butyl stearate was employed as a core material. The MicroPCMs' properties have been characterized by dry weight analysis, differential scanning calorimetry, Fourier transform IR spectra analysis and optical microscopy. The results show that the MicroPCMs were synthesized successfully and that, the phase change temperature was about 29 C, the latent heat of fusion was about 80 J g{sup -1}, the particle diameter was 20-35 {mu}m. (author)

  15. Novel Elastomeric Closed Cell Foam - Nonwoven Fabric Composite Material (Phase III)

    Science.gov (United States)

    2008-10-01

    AFRL-RX-TY-TR-2009-4577 NOVEL ELASTOMERIC CLOSED CELL FOAM – NONWOVEN FABRIC COMPOSITE MATERIAL (PHASE III) Davis, Stephen C...07-OCT-2009 Novel Elastomeric Closed Cell Foam - Nonwoven Fabric Composite Material (Phase III) FA4819-07-D-0001 62102F 4347 D2 4347D23A Davis...develop novel closed cell foam- nonwoven fabric composites to commercial scale evaluation. Armacell tasks focused on foam optimization for commercial

  16. Field experiments on the use of phase changing materials, insulation materials and passive solar radiation in the built environment

    NARCIS (Netherlands)

    Entrop, A.G.; Brouwers, H.J.H.; Reinders, A.H.M.E.

    2008-01-01

    This paper describes the development of an experimental research facility to assess the effectiveness of Phase Change Materials (PCM), that can be used for passive solar heating. Four test boxes are constructed representing the conventional and future Dutch building practices regarding insulation an

  17. Structural properties of the metastable state of phase change materials investigated by synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Merkelbach, Philipp; Eijk, Julia van; Wuttig, Matthias [I. Phys. Institut (IA), RWTH Aachen, 52056 Aachen (Germany); Braun, Carolin [Institut fuer Anorg. Chemie, CAU Kiel, 24098 Kiel (Germany)

    2008-07-01

    Phase change alloys are among the most promising materials for novel data storage devices. Since several years Phase Change Materials based on Ge-Sb-Te- alloys have been used in optical data storage solutions like rewriteable CDs and DVDs. Recently these alloys have been explored as potential candidates for fast nonvolatile electrical data storage devices in Phase Change Random Access Memory (PCRAM). Besides attracting considerable interest from the commercial point of view phase change materials are very interesting also due to their remarkable physical properties. They have the ability to be reversibly switched within a few nanoseconds between the amorphous and the crystalline phase, while changing their physical properties such as optical reflectivity and electrical resistivity significantly. Even though the electronic properties show a drastical contrast such fast transitions can only be caused by small atomic rearrangements. This behavior calls for a deeper understanding of the structural properties of the alloys. We have performed powder diffraction measurements of the crystal phase of various GeSbTe alloys, to determine the structural similarities and differences of several alloys. Understanding the crystal structure of phase change materials is a key to a deeper insight into the properties of these promising materials.

  18. Bias dependent specic contact resistance of phase change material to metal contacts

    NARCIS (Netherlands)

    Roy, Deepu; in 't Zandt, Micha; Wolters, Robertus A.M.

    2010-01-01

    Knowledge of contact resistance of phase change materials (PCM) to metal electrodes is important for scaling, device modeling and optimization of phase change random access memory (PCRAM) cells. In this article, we report the systematic determination of the speci_c contact resistance (_c) with

  19. Speci﬿c contact resistance of phase change materials to metal electrode

    NARCIS (Netherlands)

    Roy, Deepu; in 't Zandt, Micha A.A.; Wolters, Robertus A.M.

    2010-01-01

    For phase change random access memory (PCRAM) cells, it is important to know the contact resistance of phase change materials (PCMs) to metal electrodes at the contacts. In this letter, we report the systematic determination of the speci﬿c contact resistance (Ͽc ) of doped Sb2Te and Ge2Sb2Te5 to TiW

  20. Accurate switching intensities and length scales in quasi-phase-matched materials

    DEFF Research Database (Denmark)

    Bang, Ole; Graversen, Torben Winther; Corney, Joel Frederick

    2001-01-01

    We consider unseeded typeI second-harmonic generation in quasi-phase-matched quadratic nonlinear materials and derive an accurate analytical expression for the evolution of the average intensity. The intensity- dependent nonlinear phase mismatch that is due to the cubic nonlinearity induced by qu...

  1. Bias dependent specic contact resistance of phase change material to metal contacts

    NARCIS (Netherlands)

    Roy, Deepu; in 't Zandt, Micha; Wolters, Robertus A.M.

    2010-01-01

    Knowledge of contact resistance of phase change materials (PCM) to metal electrodes is important for scaling, device modeling and optimization of phase change random access memory (PCRAM) cells. In this article, we report the systematic determination of the speci_c contact resistance (_c) with volta

  2. Effect of microencapsulated phase change material in sandwich panels

    Energy Technology Data Exchange (ETDEWEB)

    Castellon, Cecilia; Medrano, Marc; Roca, Joan; Cabeza, Luisa F. [GREA Innovacio Concurrent, Edifici CREA, Universitat de Lleida, Pere de Cabrera s/n, 25001 Lleida (Spain); Navarro, Maria E.; Fernandez, Ana I. [Departamento de Ciencias de los Materiales e Ingenieria Metalurgica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); Lazaro, Ana; Zalba, Belen [Instituto de Investigacion en Ingenieria de Aragon, I3A, Grupo de Ingenieria Termica y Sistemas Energeticos (GITSE), Dpto. Ingenieria Mecanica, Area de Maquinas y Motores Termicos, Universidad de Zaragoza, Campus Politecnico Rio Ebro, Edificio ' ' Agustin de Betancourt,' ' Maria de Luna s/n, 50018 Zaragoza (Spain)

    2010-10-15

    Sandwich panels are a good option as building materials, as they offer excellent characteristics in a modular system. The goal of this study was to demonstrate the feasibility of using the microencapsulated PCM (Micronal BASF) in sandwich panels to increase their thermal inertia and to reduce the energy demand of the final buildings. In this paper, to manufacture the sandwich panel with microencapsulated PCM three different methods were tested. In case 1, the PCM was added mixing the microencapsulated PCM with one of the components of the polyurethane. In the other two cases, the PCM was added either a step before (case 2) or a step after (case 3) to the addition of the polyurethane to the metal sheets. The results show that in case 1 the effect of PCM was overlapped by a possible increase in thermal conductivity, but an increase of thermal inertia was found in case 3. In case 2, different results were obtained due to the poor distribution of the PCM. Some samples showed the effect of the PCM (higher thermal inertia), and other samples results were similar to the conventional sandwich panel. In both cases (2 and 3), it is required to industrialize the process to improve the results. (author)

  3. SBIR Grant:No-Vibration Agile Cryogenic Optical Refrigerator

    Energy Technology Data Exchange (ETDEWEB)

    Epstein, Richard

    2013-04-09

    Optical refrigeration is currently the only all-solid-state cryocooling technology that has been demonstrated. Optical cryocoolers are devices that use laser light to cool small crystal or glass cooling elements. The cooling element absorbs the laser light and reradiates it at higher energy, an example of anti-Stokes fluorescence. The dif-ference between the energy of the outgoing and incoming light comes from the thermal energy of the cooling element, which in turn becomes colder. Entitled No-Vibration Agile Cryocoolers using Optical Refrigeration, this Phase I proposal directly addressed the continued development of the optical refrigerator components necessary to transition this scientific breakthrough into National Nu-clear Security Administration (NNSA) sensor applications in line with the objectives of topic 50b. ThermoDynamic Films LLC (TDF), in collaboration with the University of New Mexico (UNM), cooled an optical-refrigerator cooling element comprised of an ytterbium-doped yttrium lithium fluoride (Yb:YLF) crystal from room tempera-ture to 123 K with about 2% efficiency. This is the world record in optical refrigera-tion and an important step toward revolutionizing cryogenic systems for sensor ap-plications. During this period, they also designed and analyzed the crucial elements of a prototype optical refrigerator including the thermal link that connects the cool-ing element with the load.

  4. Interface Characterization of Metals and Metal-nitrides to Phase Change Materials

    NARCIS (Netherlands)

    Roy, Deepu; Wolters, Rob A.M.

    2011-01-01

    We have investigated the interfacial contact properties of the CMOS compatible electrode materials W, TiW, Ta, TaN and TiN to doped-Sb2Te phase change material (PCM). This interface is characterized both in the amorphous and in the crystalline state of the doped-Sb2Te. The electrical nature of the i

  5. Reflectance and reflection phase of photonic crystal with anisotropic left-handed materials

    Science.gov (United States)

    Kang, Yongqiang; Zhang, Chunmin; Yao, Baoli

    2016-11-01

    The reflectance and reflection phase properties of one dimensional photonic crystals with anisotropic left-handed materials is investigated by transfer matrix method. It is demonstrated that the width of zero- n band gap is influenced by the incident angle, polarization, the proportion of lattice and the ratio of thickness which is different from the zero- n band gap with isotropic left hand materials. The value of reflection phase is affected by incident angle and polarization and not affected by the proportion of lattice and the ratio of thickness. These characteristic may be useful for making photonic crystal phase compensators and the dispersion compensators.

  6. Phase field crystal study of deformation and plasticity in nanocrystalline materials.

    Science.gov (United States)

    Stefanovic, Peter; Haataja, Mikko; Provatas, Nikolas

    2009-10-01

    We introduce a modified phase field crystal (MPFC) technique that self-consistently incorporates rapid strain relaxation alongside the usual plastic deformation and multiple crystal orientations featured by the traditional phase field crystal (PFC) technique. Our MPFC formalism can be used to study a host of important phase transformation phenomena in material processing that require rapid strain relaxation. We apply the MPFC model to study elastic and plastic deformations in nanocrystalline materials, focusing on the "reverse" Hall-Petch effect. Finally, we introduce a multigrid algorithm for efficient numerical simulations of the MPFC model.

  7. EERE-SBIR technology transfer opportunity. H2 Safety Sensors for H2

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, Mariann R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-12-01

    The Office of Energy Efficiency and Renewable Energy’s Fuel Cell Technologies Office (FCTO) works in partnership with industry (including small businesses), academia, and DOE's national laboratories to establish fuel cell and hydrogen energy technologies as economically competitive contributors to U.S. transportation needs. The work that is envisioned between the SBIR/STTR grantee and Los Alamos National Laboratory would involve Technical Transfer of Los Alamos Intellectual Property (IP) on Thin-film Mixed Potential Sensor (U.S. Patent 7,264,700) and associated know-how for H2 sensor manufacturing and packaging.

  8. Deriving binary phase diagrams for chromonic materials in water mixtures via fluorescence spectroscopy: cromolyn and water.

    Science.gov (United States)

    Van Hecke, Gerald R; Karukstis, Kerry K; Rayermann, Scott

    2015-01-14

    We report here the first example of a new and novel method of determining the binary temperature-composition phase diagram of a chromonic material in water using its intrinsic fluorescence. Disodium cromoglycate, or cromolyn, is an anti-allergy medicine representative of a class of compounds known as the chromonics. We have discovered that cromolyn's fluorescence is very sensitive to the polarity, hence structure, of the phase it exhibits. The fluorescence signal shifts its wavelength maximum and its shape depending on whether the cromolyn is a single phase or in coexisting phases. Since the signal due to individual phases can be identified, the fluorescence signal can reveal the temperature-induced transitions between single phase and phase coexistence regions. By studying such fluorescence data for different compositions, an isobaric temperature-composition phase diagram may be constructed. We present here a phase diagram derived from fluorescence studies that is in agreement with previous determinations using other techniques. Our results suggest that the binary phase diagrams of other intrinsically fluorescent chromonic materials, such as perylene monoimide and bisimide derivatives used in organic optoelectronic devices, solar cells, and light-emitting diodes, can be studied in water using an analogous fluorescence approach.

  9. Review on thermal energy storage with phase change: materials, heat transfer analysis and applications

    Energy Technology Data Exchange (ETDEWEB)

    Zalba, Belen; Marin, Jose M. [Dpto. Ingenieria Mecanica, Campus Politecnico, Universidad de Zaragoza, EUITIZ ' EDIFICIO B.3' Maria de Luna 3 (Actur), 50015, Zaragoza (Spain); Cabeza, Luisa F. [Dpt.d' Informatica i Enginyeria Industrial, Escola, Universitaria Politecnica, Universitat de Lleida, CREA, Jaurne 11,69,25001, Lleida (Spain); Mehling, Harald [ZAE Bayem, Division 1: Energy Conversion and Storage, Walther-Meissner-Str. 6, 85748, Garching (Germany)

    2003-02-01

    Thermal energy storage in general, and phase change materials (PCMs) in particular, have been a main topic in research for the last 20 years, but although the information is quantitatively enormous, it is also spread widely in the literature, and difficult to find. In this work, a review has been carried out of the history of thermal energy storage with solid-liquid phase change. Three aspects have been the focus of this review: materials, heat transfer and applications. The paper contains listed over 150 materials used in research as PCMs, and about 45 commercially available PCMs. The paper lists over 230 references. (Author)

  10. First order magneto-structural transition in functional magnetic materials: phase-coexistence and metastability

    Indian Academy of Sciences (India)

    S B Roy; M K Chattopadhyay; M A Manekar; K J S Sokhey; P Chaddah

    2006-11-01

    First order magneto-structural transition plays an important role in the functionality of various magnetic materials of current interest like manganese oxide systems showing colossal magnetoresistance, Gd5(Ge, Si)4 alloys showing giant magnetocaloric effects and magnetic shape memory alloys. The key features of this magneto-structural transition are phase-coexistence and metastability. This generality is highlighted with experimental results obtained in a particular class of materials. A generalized framework of disorder influenced first order phase transition is introduced to understand the interesting experimental results which have some bearing on the functionality of the concerned materials.

  11. Importance of the gas phase role to the prediction of energetic material behavior: An experimental study

    Science.gov (United States)

    Ali, A. N.; Son, S. F.; Asay, B. W.; Sander, R. K.

    2005-03-01

    Various thermal (radiative, conductive, and convective) initiation experiments are performed to demonstrate the importance of the gas phase role in combustion modeling of energetic materials (EM). A previously published condensed phase model that includes a predicted critical irradiance above which ignition is not possible is compared to experimental laser ignition results for octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and 2,4,6-trinitrotoluene (TNT). Experimental results conflict with the predicted critical irradiance concept. The failure of the model is believed to result from a misconception about the role of the gas phase in the ignition process of energetic materials. The model assumes that ignition occurs at the surface and that evolution of gases inhibits ignition. High speed video of laser ignition, oven cook-off and hot wire ignition experiments captures the ignition of HMX and TNT in the gas phase. A laser ignition gap test is performed to further evaluate the effect of gas phase laser absorption and gas phase disruption on the ignition process. Results indicate that gas phase absorption of the laser energy is probably not the primary factor governing the gas phase ignition observations. It is discovered that a critical gap between an HMX pellet and a salt window of 6mm±0.4mm exists below which ignition by CO2 laser is not possible at the tested irradiances of 29W /cm2 and 38W/cm2 for HMX ignition. These observations demonstrate that a significant disruption of the gas phase, in certain scenarios, will inhibit ignition, independent of any condensed phase processes. These results underscore the importance of gas phase processes and illustrate that conditions can exist where simple condensed phase models are inadequate to accurately predict the behavior of energetic materials.

  12. Effective anisotropy and coercivity in nanocrystalline single-phase NdFeB permanent magnetic material

    Institute of Scientific and Technical Information of China (English)

    韩广兵; 高汝伟; 冯维存; 刘汉强; 王标; 张鹏; 陈伟; 李卫; 郭永权

    2003-01-01

    The effect of exchange-coupling interaction on the effective anisotropy and its varying tendency in nanocrystalline single-phase NdFeB permanent magnetic material have been investigated. The results show that the exchange-coupling interaction between grains makes the effective anisotropy of material, Keff, decrease with the reduction of grain size. The variation of Keff is basically the same as that of coercivity. The decrease in effective anisotropy is the main reason of the reduction of coercivity for nanocrystalline single-phase NdFeB permanent magnetic material. In order to get high anisotropy and coercivity in nanocrystalline single-phase NdFeB permanent material, the grain size should be larger than 35 nm.

  13. Summary of workshop on high temperature materials based on Laves phases

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-08-01

    The Offices of Fossil Energy and Basic Energy Sciences of the Department of Energy jointly sponsored the Workshop on High Temperature Materials Based on Laves Phases in conjunction with the Tenth Annual Conference on Fossil Energy Materials held at the Radisson Summit Hill Hotel in Knoxville, Tennessee on May 14-16, 1996. The objective of this workshop was to review the current status and to address critical issues in the development of new-generation high-temperature structural materials based on Laves phases. The one-day workshop included two sessions of overview presentations and a session of discussion on critical scientific and technological issues. The Laves phases represent an abundant class of intermetallic alloys with possible high-temperature structural applications. Laves phases form at or near the AB{sub 2} composition, and there are over 360 binary Laves phases. The ability of these alloys to dissolve considerable amounts of ternary alloying additions provides over 900 combined binary and ternary Laves phases. Many Laves phases have unique properties which make them attractive for high-temperature structural use. At half their homologous temperature, they retain >0.85 of their ambient yield strength, which is higher than all other intermetallics. Many of the Laves phases also have high melting temperatures, excellent creep properties, reasonably low densities, and for alloys containing Cr, Al, Si or Be, good oxidation resistance. Despite these useful properties, the tendency for low-temperature brittleness has limited the potential application of this large class of alloys.

  14. Microstructure-property relationships in digitally generated three-dimensional, two-phase, liquid phase sintered materials

    Science.gov (United States)

    Lee, Sukbin

    In studying microstructure-property relationships, it is of great interest to reveal the effect of individual microstructural parameters on the properties of the materials in all three dimensions. However, it is not easy to obtain experimentally samples in which the individual microstructural features are independently controlled. Even though one can prepare such samples, conventional materials characterization is based on the data obtained from two-dimensional plane sections of the samples. Since many problems related to the properties of materials are three-dimensional in nature, conventional two-dimensional characterization is not always sufficient to describe the microstructure quantitatively. Also, many property experiments are destructive and therefore one needs to repeat the process many times to map the properties as a function of the microstructural parameters. Considerable effort has been made to reconstruct three-dimensional microstructures using serial sectioning in recent years in order to determine three-dimensional microstructural features of two-phase composite materials directly. While this approach yields three-dimensional data on the size, shape, and spatial correlation of particles, it demands difficult and time-consuming steps. Thus, numerical reconstruction or synthesis methods can contribute significantly to modeling three-dimensional microstructures, especially two-phase composite microstructures for this project. One objective of this project is to introduce a procedure for generating three-dimensional digital microstructures representing two-phase composite materials containing isotropically coarsened particles in the surrounding matrix phase. In order to achieve the goal, a three-dimensional, Q-state Monte Carlo Potts model of isotropic particle coarsening in a system with full wetting of particles by matrix is introduced to investigate the coarsening kinetics and microstructures associated with this process. By imposing the condition of

  15. Experimental data showing the thermal behavior of a flat roof with phase change material

    Directory of Open Access Journals (Sweden)

    Ayça Tokuç

    2015-12-01

    Full Text Available The selection and configuration of building materials for optimal energy efficiency in a building require some assumptions and models for the thermal behavior of the utilized materials. Although the models for many materials can be considered acceptable for simulation and calculation purposes, the work for modeling the real time behavior of phase change materials is still under development. The data given in this article shows the thermal behavior of a flat roof element with a phase change material (PCM layer. The temperature and energy given to and taken from the building element are reported. In addition the solid–liquid behavior of the PCM is tracked through images. The resulting thermal behavior of the phase change material is discussed and simulated in [1] A. Tokuç, T. Başaran, S.C. Yesügey, An experimental and numerical investigation on the use of phase change materials in building elements: the case of a flat roof in Istanbul, Build. Energy, vol. 102, 2015, pp. 91–104.

  16. T-p phase diagrams and the barocaloric effect in materials with successive phase transitions

    Science.gov (United States)

    Gorev, M. V.; Bogdanov, E. V.; Flerov, I. N.

    2017-09-01

    An analysis of the extensive and intensive barocaloric effect (BCE) at successive structural phase transitions in some complex fluorides and oxyfluorides was performed. The high sensitivity of these compounds to a change in the chemical pressure allows one to vary the succession and parameters of the transformations (temperature, entropy, baric coefficient) over a wide range and obtain optimal values of the BCE. A comparison of different types of schematic T-p phase diagrams with the complicated T( p) dependences observed experimentally shows that in some ranges of temperature and pressure the BCE in compounds undergoing successive transformations can be increased due to a summation of caloric effects associated with distinct phase transitions. The maximum values of the extensive and intensive BCE in complex fluorides and oxyfluorides can be realized at rather low pressure (0.1-0.3 GPa). In a narrow temperature range around the triple points conversion from conventional BCE to inverse BCE is observed, which is followed by a gigantic change of both \\vertΔ S_BCE\\vert and \\vertΔ T_AD\\vert .

  17. Preparation of n-tetradecane-containing microcapsules with different shell materials by phase separation method

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Rui [Department of Chemical Engineering, Tsinghua University, Beijing (China); Zhang, Yan; Zhang, Qingwu [Department of Chemical Engineering, China University of Mining and Technology, Beijing (China); Wang, Xin; Zhang, Yinping [Department of Building Science, Tsinghua University, Beijing (China)

    2009-10-15

    Microcapsules for thermal energy storage and heat-transfer enhancement have attracted great attention. Microencapsulation of n-tetradecane with different shell materials was carried out by phase separation method in this paper. Acrylonitrile-styrene copolymer (AS), acrylonitrile-styrene-butadiene copolymer (ABS) and polycarbonate (PC) were used as the shell materials. The structures, morphologies and the thermal capacities of the microcapsules were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The ternary phase diagrams showed the potential encapsulation capabilities of the three shell materials. The effects of the shell/core ratio and the molecular weight of the shell material on the encapsulation efficiency and the thermal capacity of the microcapsules were also discussed. Microcapsules with melting enthalpy > 100 J/g, encapsulation efficiency 66-75%, particle size<1 {mu}m were obtained for all three shell materials. (author)

  18. Generalized thermoelastic interaction in functional graded material with fractional order three-phase lag heat transfer

    Institute of Scientific and Technical Information of China (English)

    Ibrahim A. Abbas

    2015-01-01

    The present work is concerned with the solution of a problem on thermoelastic interactions in a functional graded material due to thermal shock in the context of the fractional order three-phase lag model. The governing equations of fractional order generalized thermoelasticity with three-phase lag model for functionally graded materials (FGM) (i.e., material with spatially varying material properties) are established. The analytical solution in the transform domain is obtained by using the eigenvalue approach. The inversion of Laplace transform is done numerically. The graphical results indicate that the fractional parameter has significant effects on all the physical quantities. Thus, we can consider the theory of fractional order generalized thermoelasticity an improvement on studying elastic materials.

  19. Synthesis of the Novel MAX Phases for the Future Nuclear Fuel Cladding and Structural Materials

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Seung Hyeok [Kyunghee Univ., Yongin (Korea, Republic of); Kim, Taehee; Lee, Taegyu; Ryu, H. J. [KAIST, Daejeon (Korea, Republic of)

    2016-10-15

    With these properties, the MAX phases are expected to be used for the Accident Tolerant Fuel (ATF) cladding and oxidation/corrosion resistance materials. Especially, the MAX phase can be used for the Gen-IV, SFR and HTGR, component materials which have to possess the thermal and corrosion resistance. The zirconium has been used to the nuclear industry for fuel cladding because of the small thermal neutron cross-section. Zr-based MAX phase was discovered by group Lapauw et al. They observed the Zr{sub 2}AlC and Zr{sub 3}AlC{sub 2} with the X-ray diffraction (XRD) patterns and backscattered electron detector. Fabrication of the Zr-containing MAX phase was investigated for nuclear fuel cladding and structural materials applications. A MAX phase with the Zr{sub 3}AlC{sub 2} structure was synthesized by spark plasma sintering of a powder mixture targeting (Zr{sub 0.5}Cr{sub 0.5}){sub 4}AlC{sub 3}. The formation of MAX phases was confirmed by XRD and EDS of sintered samples. In the future work, the electron probe micro analyzer (EPMA) and transmission electron microscopy (TEM) are required to certain analyze the elements composition and formation of the MAX phase.

  20. Compositional phase stability of strongly correlated electron materials within DFT+U

    Science.gov (United States)

    Isaacs, Eric B.; Marianetti, Chris A.

    2017-01-01

    Predicting the compositional phase stability of strongly correlated electron materials is an outstanding challenge in condensed matter physics. In this work, we employ the density functional theory plus U (DFT +U ) formalism to address the effects of local correlations due to transition metal d electrons on compositional phase stability in the prototype phase stable and separating materials LixCoO2 and olivine LixFePO4 , respectively. We introduce a spectral decomposition of the DFT +U total energy, revealing the distinct roles of the filling and ordering of the d orbital correlated subspace. The on-site interaction U drives both of these very different materials systems towards phase separation, stemming from enhanced ordering of the d orbital occupancies in the x =0 and x =1 species, whereas changes in the overall filling of the d shell contribute negligibly. We show that DFT +U formation energies are qualitatively consistent with experiments for phase stable LixCoO2 , phase separating LixFePO4 , and phase stable LixCoPO4 . However, we find that charge ordering plays a critical role in the energetics at intermediate x , strongly dampening the tendency for the Hubbard U to drive phase separation. Most relevantly, the phase stability of Li1 /2CoO2 within DFT +U is qualitatively incorrect without allowing charge ordering, which is problematic given that neither charge ordering nor the band gap that it induces are observed in experiment. We demonstrate that charge ordering arises from the correlated subspace interaction energy as opposed to the double counting. Additionally, we predict the Li order-disorder transition temperature for Li1 /2CoO2 , demonstrating that the unphysical charge ordering within DFT +U renders the method problematic, often producing unrealistically large results. Our findings motivate the need for other advanced techniques, such as DFT plus dynamical mean-field theory, for total energies in strongly correlated materials.

  1. Dead lithium phase investigation of Sn-Zn alloy as anode materials for lithium ion battery

    Institute of Scientific and Technical Information of China (English)

    HUANG ZhaoWen; HU SheJun; HOU XianHua; RU Qiang; YU HongWen; ZHAO LingZhi; LI WeiShan

    2009-01-01

    In this work, based on First-principle plane wave pseudo-potential method, we have carried out an in-depth study on the possible dead lithium phase of Sn-Zn alloy as anode materials for lithium ion batteries. Through investigation, we found that the phases LixSn4Zn4(x = 2, 4, 6, 8) contributed to reversible capacity, while the phases LixSn4Zns-(x-4)(x = 4.74, 7.72) led to capacity loss due to high formation energy, namely, they were the dead lithium phases during the charge/discharge process. And we come up with a new idea that stable lithium alloy phase with high lithiation formation energy (dead lithium phase) can also result in high loss of active lithium ion, besides the traditional expression that the formation of solid electrolyte interface film leads to high capacity loss.

  2. Study on the Motion state of Powdery materials in Dense-phase Pneumatic Conveying Pipe

    Directory of Open Access Journals (Sweden)

    Lia Zhihua

    2016-01-01

    Full Text Available Using the method of computational fluid dynamics, a model is created about powdery materials flowing in the dense-phase pneumatic conveying pipe. the motion state powdery materials flowing in the horizontal and vertical pipe is simulated. It is found that in the horizontal pipe the powdery materials represent the flow of dune-like state, and continuously move forward in this form, the volume fraction of powdery materials at the pipe's bottom is large, the velocity is low; In the vertical pipe, the columnar solid-plug can form and scatter continuously, and the motion state is closer to fluidization.

  3. Sol-gel composite material characteristics caused by different dielectric constant sol-gel phases

    Science.gov (United States)

    Kimoto, Keisuke; Matsumoto, Makoto; Kaneko, Tsukasa; Kobayashi, Makiko

    2016-07-01

    Ultrasonic transducers prepared by a sol-gel composite method have been investigated in the field of nondestructive testing (NDT). Sol-gel composite materials could be ideal piezoelectric materials for ultrasonic transducer applications in the NDT field, and a new sol-gel composite with desirable characteristics has been developed. Three kinds of sol-gel composite materials composed of different dielectric constant sol-gel phases, Pb(Zr,Ti)O3 (PZT), Bi4Ti3O12 (BiT), and BaTiO3 (BT), and the same piezoelectric powder phase, PbTiO3 (PT), were fabricated and their properties were compared quantitatively. As a result, the PT/BT, sol-gel composite with the highest dielectric constant sol-gel phase showed the highest d 33 and signal strength. In addition, only PT/BT was successfully poled by room-temperature corona poling with reasonable signal strength.

  4. Nanocasting of Periodic Mesoporous Materials as an Effective Strategy to Prepare Mixed Phases of Titania

    Directory of Open Access Journals (Sweden)

    Luther Mahoney

    2015-12-01

    Full Text Available Mesoporous titanium dioxide materials were prepared using a nanocasting technique involving silica SBA-15 as the hard-template. At an optimal loading of titanium precursor, the hexagonal periodic array of pores in SBA-15 was retained. The phases of titanium dioxide could be easily varied by the number of impregnation cycles and the nature of titanium alkoxide employed. Low number of impregnation cycles produced mixed phases of anatase and TiO2(B. The mesoporous TiO2 materials were tested for solar hydrogen production, and the material consisting of 98% anatase and 2% TiO2(B exhibited the highest yield of hydrogen from the photocatalytic splitting of water. The periodicity of the pores was an important factor that influenced the photocatalytic activity. This study indicates that mixed phases of titania containing ordered array of pores can be prepared by using the nanocasting strategy.

  5. The solidification of two-phase heterogeneous materials: Theory versus experiment

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bin; KIM Tongbeum; LU TianJian

    2009-01-01

    The solidification behavior of two-phase heterogeneous materials such as close-celled aluminum foams was analytically studied. The proposed analytical model can precisely predict the location of solidification front as well as the full solidification time for a two-phase heterogeneous material composed of aluminum melt and non-conducting air pores. Experiments using distilled water simulating the aluminum melt to be solidified (frozen) were subsequently conducted to validate the analytical model for two selected porosities (ε), ε=0 and 0.5. Full numerical simulations with the method of finite difference were also performed to examine the influence of pore shape on solidification. The remarkable agreement between theory and experiment suggests that the delay of solidification in the two-phase heterogeneous material is mainly caused by the reduction of bulk thermal conductivity due to the presence of pores, as this is the sole mechanism accounted for by the analytical model for solidification in a porous medium.

  6. Defense Small Business Innovation Research Program (SBIR) Abstracts of Phase 2 Awards: Fiscal Year 1987 (ARMY)

    Science.gov (United States)

    1987-01-01

    AND SECONDARY STORAGE HAVE DROPPED DRAMATICALLY. AS A RESULT, THERE IS A RAPIDLY GROWING INTEREST IN GEOGRAPHIC INFORMATION SYSTEMS (GIS) BOTH WITHIN...MEASURING INSTRUMENTS. THE ELECTROCHEMICAL ACTIVITY OF MICRO-AREAS LOCATED AT THE INTERSECTION OF A WIRE- SEGEMENT COMBINATION IS THUS SCANNED UNDER...COMPUTER CONTROL. IONIC CURRENTS (WITH OR WITHOUT CATHODIC PROTECTION) TO INDIVIDUAL SEGEMENTS CAN ALSO BE DETERMINED BY APPROPRIATE SWITCHING. A

  7. 2007 Beyond SBIR Phase II: Bringing Technology Edge to the Warfighter

    Science.gov (United States)

    2007-08-23

    barriers to transition A Lean Six Sigma Kaizen Event will be scheduled in FY08 to develop the detailed processes for accomplishing these objectives. 4...productivity Lean Processes with Six Sigma capability throughout the enterprise and supply chain Lean Processes with Six Sig a capability throughout the

  8. Small Business Innovative Research (SBIR) Literacy Project Phase I. Final Report.

    Science.gov (United States)

    Comsis Corp., Silver Spring, MD.

    An assessment of the information needs of providers of literacy services examined whether these needs could be met through an electronic information and communications system (EICS). The needs assessment was sent to 300 literacy providers; 134 responded. Responses indicated that literacy providers would benefit from a central, easily accessible…

  9. Security Hardened Cyber Components for Nuclear Power Plants: Phase I SBIR Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Franusich, Michael D. [SpiralGen, Inc., Pittsburgh, PA (United States)

    2016-03-18

    SpiralGen, Inc. built a proof-of-concept toolkit for enhancing the cyber security of nuclear power plants and other critical infrastructure with high-assurance instrumentation and control code. The toolkit is based on technology from the DARPA High-Assurance Cyber Military Systems (HACMS) program, which has focused on applying the science of formal methods to the formidable set of problems involved in securing cyber physical systems. The primary challenges beyond HACMS in developing this toolkit were to make the new technology usable by control system engineers and compatible with the regulatory and commercial constraints of the nuclear power industry. The toolkit, packaged as a Simulink add-on, allows a system designer to assemble a high-assurance component from formally specified and proven blocks and generate provably correct control and monitor code for that subsystem.

  10. Faigue Avoidance Scheduling Tool (FAST) Phase II SBIR Final Report, Part 1

    Science.gov (United States)

    2006-05-01

    linearized with the proper regression coefficients it is seen that there are no systematic deviations that would obfuscate or distort the linear relationship...palate malformation, and missing digits. Primate studies have shown an association with spontaneous abortion (SAB), stillbirth, decreased weight gain and...Aleve)? Yes /No "* Ketoprofen (Orudis KT)? Yes /No "• Cortisone or other steroid medication? Yes /No "* Erythromycin? Yes / No "* Nifedipine? Yes

  11. Defense Small Business Innovation Research Program (SBIR). Volume 2. Navy Abstracts of Phase 1 Awards 1991

    Science.gov (United States)

    1991-01-01

    Phone: (408) 734-2400 PI: Dr. Paul Cowell Title: Tactical Cryptologic Exploitation of Over-TheHorizon (OTH) Radar Abstract: Navy combatant ships have a...ARLINGTON, VA 15 CoAntract . N60530-91-C-0283 Phone: (03) 751-3422 1: Philp A. Shaw M Title: Deformable Control Surfices with Shape Manory Alloy Aetuatoru...LABORATORIES, INC. DARPA 91-235 SDIO 91-004 SCIENCE AND APPLIED TECHNOLOGY, INC. RUDOLF, PAUL G. AI 91-090 AF 91-059 SCIENCE AND ENGINEERING ASSOC. S-TRON DNA 91

  12. Defense Small Business Innovation Research Program (SBIR) Abstracts of Phase I Awards 1984.

    Science.gov (United States)

    1985-04-16

    INTEGRATED BUILDING ENERGY EVALUATION PROGRAM, TO BE APPLIED TO LARGE BUILDINGS THAT DETERMINES THE OVERALL BUILDING ENERGY EFFICIENCY AND DIAGNOSES SPECIFIC...STANDARDS TO PROVIDE BUILDING ENERGY EFFICIENCY EVALUATION. MORE IMPORTANTLY, IT WILL INDICATE AREAS OF INEFFICIENCY TO BE IMPROVED. MANY DATA INPUTS TO

  13. Defense Small Business Innovation Research Program (SBIR). Volume 1. Army Abstracts of Phase 1 Awards 1991

    Science.gov (United States)

    1991-01-01

    CURRENTLY IS DEVELOPING SEVERAL NOVEL ENZYMES FOR INDUSTRIAL MARKETS USING NEWLY ISOLATED BACTERIA , INCLUDING ONE PROCESS IN PILOT SCALE PRODUCTION...THE PROPOSED EFFORT WILL EXTEND UPON THIS PREVIOUS WORK iN NON-METALLIC MINE DETECTION. PERCEPTUAL IMAGES Topic#: 91-139 wD. 91tED 15951 LOS GATOS ...BLVD, SUITE 7 Office: ETDL LOS GATOS , CA 95032 Contract #: Phone: (408) 356-4562 PI: JOHN L. MILLER Title: ANALYSIS OF A FLAT PANEL AUTOSTEREOSCOPIC

  14. Defense Small Business Innovation Research Program (SBIR) Abstracts of Phase 1 Awards 1983.

    Science.gov (United States)

    1984-04-06

    RESTORATIVE ALGORITHM TO RECOVER A SET OF IMAGES OF PARALLEL SURFACES WITHIN THE OBJECT. THE METHOD IS COMPLEMENTARY TO COMPUTED TOMOGRAPHY (CT); BUT...OUT- LINING VARIOUS PERIODONTAL AND ORAL SURGERY APPLICATIONS. WHILE NOT INTENDED TO COMPLETELY REPLACE RADIOGRAPHS, THE RESEARCH AS OUTLINED HEREIN...TITLE: APPLICATION OF COMPTON INTERACTION TOMOGRAPHY FOR NON- DESTRUCTIVE INSPECTION OF LAMINATED COMPOSITE STRUCTURES TOPIC: 99 OFFICE: NASC AN

  15. Computational Platform for Flux Analysis Using 13C-Label Tracing- Phase I SBIR Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Van Dien, Stephen J.

    2005-04-12

    Isotopic label tracing is a powerful experimental technique that can be combined with metabolic models to quantify metabolic fluxes in an organism under a particular set of growth conditions. In this work we constructed a genome-scale metabolic model of Methylobacterium extorquens, a facultative methylotroph with potential application in the production of useful chemicals from methanol. A series of labeling experiments were performed using 13C-methanol, and the resulting distribution of labeled carbon in the proteinogenic amino acids was determined by mass spectrometry. Algorithms were developed to analyze this data in context of the metabolic model, yielding flux distributions for wild-type and several engineered strains of M. extorquens. These fluxes were compared to those predicted by model simulation alone, and also integrated with microarray data to give an improved understanding of the metabolic physiology of this organism.

  16. Defense Small Business Innovation Research Program (SBIR). Abstracts of Phase 2 Awards. 1986

    Science.gov (United States)

    1986-01-01

    RANGE OF TACTILE, AUDIBLE AND VISUAL TEACHING SYSTEMS TO TEACH CHORDIC COMMANDS IN A TEN KEY HANDGRIP SYSTEM TO ALLOW FOR RAPID AND INSTINCTIVE DATA...ADVANCED RE-ENTRY BODY AND WAKE FLOW FIELD CODES, INCLUDING NON- EQUILIBRIUM THERMOCHEMISTRY , TO PREDICT THE EFFECT OF VARIOUS QUENCHANTS ON WAKE ELECTRON...ANALYZE ACTUAL SIMULATIONS THAT HAVE BEEN DESIGNED FOR A HIGH-TECHNOLOGY WEAPON SYSTEM. WE WILL DESIGN AND IMPLEMENT AN EXPERT TEACHER MODEL THAT TEACHES

  17. DOE SBIR Phase II Final Technical Report - Assessing Climate Change Effects on Wind Energy

    Energy Technology Data Exchange (ETDEWEB)

    Whiteman, Cameron [Vertum Partners LP, Los Angeles, CA (United States); Capps, Scott [Vertum Partners LP, Los Angeles, CA (United States)

    2014-11-05

    Specialized Vertum Partners software tools were prototyped, tested and commercialized to allow wind energy stakeholders to assess the uncertainties of climate change on wind power production and distribution. This project resulted in three commercially proven products and a marketing tool. The first was a Weather Research and Forecasting Model (WRF) based resource evaluation system. The second was a web-based service providing global 10m wind data from multiple sources to wind industry subscription customers. The third product addressed the needs of our utility clients looking at climate change effects on electricity distribution. For this we collaborated on the Santa Ana Wildfire Threat Index (SAWTi), which was released publicly last quarter. Finally to promote these products and educate potential users we released “Gust or Bust”, a graphic-novel styled marketing publication.

  18. Defense Small Business Innovation Research Program (SBIR). Abstracts of Phase II Awards. 1985.

    Science.gov (United States)

    1985-01-01

    8217 CAPABILITY TO ACCURATELY DETECT THESE TOXINS AT LEVELS WELL BELOW THOSE LETHAL TO HUMANS . ONE OF THE MOST COMMON GROUPS OF NATURALLY OCCURRING TOXINS IS THE... TRICHOTHECENE GROUP (E.G., T-2 TOXIN) WHICH CONSISTS OF HIGHLY TOXIC SECONDARY METABOLITE OF MOLDS THAT HAVE BEEN IDENTIFIED AS THE CAUSE OF TOXICOSES...IN HUMANS AND ANIMALS. THE U.S. ARMY HAS SPECU- LATED THAT T-2 TOXIN HAS BEEN USED AND THUS HAS SOUGHT ASSISTANCE IN DEVELOPING ANALYTICAL METHODS FOR

  19. Defense Small Business Innovation Research Program (SBIR). Volume 3. Air Force Abstracts of Phase 1 Awards

    Science.gov (United States)

    1990-01-01

    ROBOTS. KINOPHASE 14 HOLLY HILL DR AMHERST, NH 03031 Program Manager: GENE C KOCH Contract #: Title: LIQUID CRYSTAL SWITCHABLE KINOFORM LENSES FOR...NETWORKS WILL BE USED TO DEVELOP A REAL- CIME , MULTIMODALITY, NONINTRUSIVE PHYSIOLOGICAL METRIC OF MENTAL WORKLOAD. OUR METRIC WILL MEASURE MENTAL

  20. SBIR Phase II Final Report for Scalable Grid Technologies for Visualization Services

    Energy Technology Data Exchange (ETDEWEB)

    Sebastien Barre; Will Schroeder

    2006-10-15

    This project developed software tools for the automation of grid computing. In particular, the project focused in visualization and imaging tools (VTK, ParaView and ITK); i.e., we developed tools to automatically create Grid services from C++ programs implemented using the open-source VTK visualization and ITK segmentation and registration systems. This approach helps non-Grid experts to create applications using tools with which they are familiar, ultimately producing Grid services for visualization and image analysis by invocation of an automatic process.

  1. Phase II Final Project Report SBIR Project: "A High Efficiency PV to Hydrogen Energy System"

    Energy Technology Data Exchange (ETDEWEB)

    Slade, A; Turner, J; Stone, K; McConnell, R

    2008-09-02

    The innovative research conducted for this project contributed greatly to the understanding of generating low-cost hydrogen from solar energy. The project’s research identified two highly leveraging and complementary pathways. The first pathway is to dramatically increase the efficiency of converting sunlight into electricity. Improving solar electric conversion efficiency directly increases hydrogen production. This project produced a world record efficiency for silicon solar cells and contributed to another world record efficiency for a solar concentrator module using multijunction solar cells. The project’s literature review identified a second pathway in which wasted heat from the solar concentration process augments the electrolysis process generating hydrogen. One way to do this is to use a “heat mirror” that reflects the heat-producing infrared and transmits the visible spectrum to the solar cells; this also increases solar cell conversion efficiency. An economic analysis of this concept confirms that, if long-term concentrator photovoltaic (CPV) and solid-oxide electrolyzer cost goals can be achieved, hydrogen will be produced from solar energy cheaper than the cost of gasoline. The potential public benefits from this project are significant. The project has identified a potential energy source for the nation’s future electricity and transportation needs that is entirely “home grown” and carbon free. As CPV enter the nation’s utility markets, the opportunity for this approach to be successful is greatly increased. Amonix strongly recommends further exploration of this project’s findings.

  2. Defense Small Business Innovation Research Program (SBIR). Volume 1. Army Abstracts of Phase 1 Awards 1993

    Science.gov (United States)

    1993-01-01

    pressure, without any pulsations or flow noise. A pump operating off a vehicular battery could weigh less than 8 lb. with a size of less than I cubic ...pressure of oxygen is developed due to ion flow across a solid electrolyte (yttrium-doped zirconia ) in the presence of an electric potential. This pump...chemical reactions. Dehydrated food powders and particles are also used in "liquid meals" for dental patients. However, dehydrated foods traditionally

  3. An Atmospheric Boundary Layer Stability Estimator for Urban Areas. SBIR Phase 1 Feasibility Study

    Science.gov (United States)

    1992-12-01

    Scire S. R. Hanna Sigma Research Corporation 196 Baker Avenue Concord, MA 01742 Under Contract DAAD07-91-C-0135 Contract Monitor Frank V. Hansen ARL-CR...Sands Missile Range, NM 88003-5501 11. SUPPLEMENTARY NOTES Frank V. Hansen ( Contract Monitor) 12a. DISTRIBUTION /AVAILABILITY STATEMENT 12b. DISTRIBUTION...In the constant flux layer. Quart. J. Roy. Meteor. Soc., 96, 715-721. Gifford, F.A., Jr., 1976: Turbulent Diffusion--Typing schemes: A Review. Mucl

  4. Defense Small Business Innovation Research Program (SBIR). Volume 1. Army Abstracts of Phase 1 Awards 1990

    Science.gov (United States)

    1990-01-01

    HEADSET. IMAGING AND SENSING TECHNOLOGY CORPORATION , WITH COMPUTER SOFTWARE, ELECTRONIC DESIGN AND SPECIAL HEADSET DISPLAY EXPERTISE, ASSISTED BY ITS...PROJECT. WE HAVE IDENTIFIED THE COMMUNICATIN LINK, THE DISPLAY AND THE VOICE RECOGNITION UNIT AS CRITICAL SUBSYSTEMS, ND A NUMBER OF THE OFF-THE-SHELF...PHYSICAL OPTICS CORPORATION (POC) PROPOSES TO DEVELOP BROADBAND PASSIVE LASER FILTERS WHICH WILL OPERATE IN THE VISIBLE AND NEAR IR PORTION OF THE SPECTRUM

  5. National SBIR Phase III Commercialization Conference Held in Orlando, Florida on Jun 10 and 11, 1993

    Science.gov (United States)

    1993-06-01

    company goal Is to build a rapid software development technology using the latest proqrarrming and representation language innovations. Logistica M Is a...sirrpest level Logistica looks like Scheme it differs in two important ways: First. It allows symbols to be bound to any number of S "- , 2 1 values...straightforward lunctional programnvrng approach to the powerful and highly descnptive expression of alternative symbouic comrutptions Logistica pro- vides

  6. Phase 2 SBIR Final Report: An Ultra-Sensitive Optical Biosensor for Flood Safety

    Science.gov (United States)

    2007-11-02

    equipment includes an autoclave, incubator, an orbital shaker incubator, refrigerator, precision balance , and UV/Visible spectrophotometer for quantification...Layer # Materia l Growth Technique Thickness Thickness Uniformity over wafer Wafer-to- wafer Tolerance Index of Refraction at λ = 633 nm Index...continuity (mass balance ) of each diffusing species in the mixture. Consider the geometry of a microchannel shown in Figure 8-5. The channel has length L

  7. Defense Small Business Innovation Research Program (SBIR). Volume 2. Navy Abstracts of Phase 1 Awards 1993

    Science.gov (United States)

    1993-01-01

    Office: NCCOSC SAN DIEGO, CA 92108 Contract #: N66001-93-C-7008 Phone: (619) 281-3009 PI: NATHANIEL L. COHEN Title: Integrated Broadband Radar...automatic data quality checking and a simplified user interface. SYSTEMS TECHNOLOGY, INC. Topic#: 92-164 IlV 92PAIT-291 13766 S. HAWTHORNE BLVD Office...NAWCFTEG HAWTHORNE , CA 90250 Contract #: N00421-93-C-0108 Phone: (310) 679-2281 PI: WALTER A. JOHNSON Title: Use of Heads-up Displays in the E-2C Cockpit

  8. Defense Small Business Innovation Research Program (SBIR). Volume 1. Army Abstracts of Phase 1 Awards 1992

    Science.gov (United States)

    1992-01-01

    correlation of SERA test data to copper contamination levels in the solder plating bath; and the application of statistical process control techniques, real...earlier experience with the PAVE PILLAR avionics architecture, embedded expert system design. and fault-tolerant system analysis and simulation methods... Electroplate at 3 levels of current densities to get 1,3,and 6um thickness. (2) Hot tin dip coating using 3 different coating cycles to produce 1,3,and 6um

  9. 76 FR 77510 - Applications for New Awards; Small Business Innovation Research Program (SBIR)-Phase I

    Science.gov (United States)

    2011-12-13

    ... States economy and ensures that Federal agencies assist the private sector in its manufacturing... Sharing or Matching: This program does not require cost sharing or matching. 3. Other: The total of...

  10. Defense Small Business Innovation Research Program (SBIR). Abstracts of Phase I Awards. 1985.

    Science.gov (United States)

    1985-01-01

    34CANNED" PROGRAM. THE SYNERGY OF HELICAL SCAN AND CGI IS A TECHNICAL ADVANTAGE BY CON- CENTRATING THE PERCEIVED INFORMATION IN THE ROBOT PICK-UP RASTER...COUNT * NEEDED FOR THE CALCULATION. * NW SYSTEMS SDIO $ 0 36 PANORAMA TRAIL ROCHESTER, NY 14525 DR CAROL A NIZNIK TITLE: STRATEGIC DEFENSE DATA BASE

  11. Enabling universal memory by overcoming the contradictory speed and stability nature of phase-change materials.

    Science.gov (United States)

    Wang, Weijie; Loke, Desmond; Shi, Luping; Zhao, Rong; Yang, Hongxin; Law, Leong-Tat; Ng, Lung-Tat; Lim, Kian-Guan; Yeo, Yee-Chia; Chong, Tow-Chong; Lacaita, Andrea L

    2012-01-01

    The quest for universal memory is driving the rapid development of memories with superior all-round capabilities in non-volatility, high speed, high endurance and low power. Phase-change materials are highly promising in this respect. However, their contradictory speed and stability properties present a key challenge towards this ambition. We reveal that as the device size decreases, the phase-change mechanism changes from the material inherent crystallization mechanism (either nucleation- or growth-dominated), to the hetero-crystallization mechanism, which resulted in a significant increase in PCRAM speeds. Reducing the grain size can further increase the speed of phase-change. Such grain size effect on speed becomes increasingly significant at smaller device sizes. Together with the nano-thermal and electrical effects, fast phase-change, good stability and high endurance can be achieved. These findings lead to a feasible solution to achieve a universal memory.

  12. Green material composites from renewable resources: Polymorphic transitions and phase diagram of beeswax/rosin resin

    Energy Technology Data Exchange (ETDEWEB)

    Gaillard, Yves [Mines-ParisTech., CEMEF, UMR CNRS 7635, 1 rue Claude Daunesse 06904 Sophia Antipolis cedex (France); Mija, Alice [University of Nice-Sophia Antipolis, Thermokinetic Group, Laboratory of Chemistry of Organic and Metallic Materials C.M.O.M., 06108 Nice Cedex 2 (France); Burr, Alain; Darque-Ceretti, Evelyne; Felder, Eric [Mines-ParisTech., CEMEF, UMR CNRS 7635, 1 rue Claude Daunesse 06904 Sophia Antipolis cedex (France); Sbirrazzuoli, Nicolas, E-mail: sbirrazz@unice.fr [University of Nice-Sophia Antipolis, Thermokinetic Group, Laboratory of Chemistry of Organic and Metallic Materials C.M.O.M., 06108 Nice Cedex 2 (France)

    2011-07-10

    Highlights: {yields} Blends of Rosin and beeswax are studied by DSC, XRD, and optical microscopy. {yields} The first phase diagram beeswax/rosin is established. {yields} Polymorphic transitions are identified and appear to be highly related to rosin content. - Abstract: Rosin and beeswax are two complex natural materials presenting numerous applications in paints, adhesives, varnishes or inks. Melted, they are particularly interesting for their adhesion properties. This paper establishes the first phase diagram beeswax/rosin blends. A systematic approach using X-ray diffraction (XRD), differential scanning calorimetry (DSC) and polarised optical microscopy (POM) has been performed in order to describe the crystallographic structure and the thermal properties of two materials, beeswax and rosin, and their blends. Indeed, melting, softening and crystallisation temperatures, polymorphic transitions but also crystalline index has been investigated. The resulting phase diagram reveals a complex behaviour in terms of phase transformation and time-dependent phenomenon mainly representative of the complex composition of beeswax.

  13. Heat transfer characteristics of coconut oil as phase change material to room cooling application

    Science.gov (United States)

    Irsyad, M.; Harmen

    2017-03-01

    Thermal comfort in a room is one of human needs in the workplace and dwellings, so that the use of air conditioning system in tropical countries is inevitable. This equipment has an impact on the increase of energy consumption. One method of minimizing the energy use is by using the phase change material (PCM) as thermal energy storage. This material utilizes the temperature difference between day and night for the storage and release of thermal energy. PCM development on application as a material for air cooling inlet, partitioning and interior needs to be supported by the study of heat transfer characteristics when PCM absorbs heat from ambient temperature. This study was conducted to determine the heat transfer characteristics on coconut oil as a phase change material. There are three models of experiments performed in this research. Firstly, an experiment was conducted to analyze the time that was needed by material to phase change by varying the temperature. The second experiment analyzed the heat transfer characteristics of air to PCM naturally convection. The third experiment analyzed the forced convection heat transfer on the surface of the PCM container by varying the air velocity. The data of experimental showed that, increasing ambient air temperature resulted in shorter time for phase change. At temperatures of 30°C, the time for phase change of PCM with the thickness of 8 cm was 1700 min, and it was stable at temperatures of 27°C. Increasing air temperature accelerated the phase change in the material. While for the forced convection heat transfer, PCM could reduce the air temperature in the range of 30 to 35°C at about 1 to 2°C, with a velocity of 1-3 m/s.

  14. Defense Small Business Innovation Research Program (SBIR). Volume 3. Air Force Abstracts of Phase 1 Awards from FY 1988 SBIR Solicitation

    Science.gov (United States)

    1989-05-01

    MANAGEMENT APPLICATIONS. THIS AUTOSTEREOSCOPIC VIDEO DISPLAY (WVD) DOES NOT REQUIRE GLASSES OR GOGGLES, AND CAN PROVIDE FULL COLOR. IT IS CRT BASED...20747 CONTRACT NUMBER: DR THOMAS TSAO TITLE: A SPECIALIZED NEURAL NETWORK BASED ON LIE GROUP THEORY FOR EXTRACTING 3D MOTION AND 3D LAYOUT OF VISIBLE...CORRESPONDENCE BETWEEN 3D RIGID MOTION AND THE INDUCED COHERENT IMAGE TRANSFORMATIONS, THIS NEURAL NETWORK IS CAPABLE OF PICKING UP 3D MOTION AND ED LOCATION

  15. Defense Small Business Innovation Research Program (SBIR). Volume 2. Navy Projects, Abstracts of Phase 1 Awards from FY 1989 SBIR Solicitation

    Science.gov (United States)

    1990-04-01

    FOUND, FROM EXPERIENCE GAINED ON THE CRITICAL SEA TEST ( CZT ) AND THE LOW FREQUENCY ACOUSTICS (LFA) PROGRAMS, THAT THE ACOUSTIC ENVIRONMENT FOR LONG RANGE...CUSTOM "ROUTING- ASIC , THE IMAGINATION WORKS PROPOSLS A NEW AND INNOVATIVE SOLUTION TO THE HARDWARE/SOFTWARE BOUNDARY PROBLEM, ENABLING A COPROCESSOR TO...AND VLSI CHIPS, INCLUDING VHSIC AND ASIC . THE NUMBER OF WORK STATIONS, COMPUTERS, SOFTWARE PACKAGES, DATA FORMATS, FILE TRANSFER STANDARDS, PLOTTER

  16. Modeling Phase Change Material in Micro-Foam Under Constant Temperature Condition (Postprint)

    Science.gov (United States)

    2014-01-01

    capture the phase change process in PCM /micro-foam systems, with the effective thermal conductivity derived from direct simulations and expressed as a...in PCM /micro-foam systems, with the effective thermal conductivity derived from direct simulations and expressed as a power law of porosity. Published...by Elsevier Ltd.1. Introduction Metal or graphite foams [1] filled with phase change materials ( PCM ) are attractive for thermal energy storage (TES

  17. SBIR & STTR

    Science.gov (United States)

    2012-10-18

    Jll) ,oiii•:J.,~oll~o;’nltoA• " "’ ’ ... ~~ ~ •.oo:I .:Ut..: I!I CI• t(lil )t’l (.>eo’lt" 4𔃻\\fiO~ lol :’f"’ )• 1~00\\lll>’ I" I ••+! lii’I’O:IIIIf

  18. THE RATE-INDEPENDENT CONSTITUTIVE MODELING FOR POROUS AND MULTI-PHASE NANOCRYSTALLINE MATERIAL

    Institute of Scientific and Technical Information of China (English)

    Zhou Jianqiu; Li Yuanling; Zhang Zhenzhong

    2007-01-01

    To determine the time-independent constitutive modeling for porous and multiphase nanocrystalline materials and understand the effects of grain size and porosity on their mechanical behavior, each phase was treated as a mixture of grain interior and grain boundary, and pores were taken as a single phase, then Budiansky's self-consistent method was used to calculate the Young's modulus of porous, possible multi-phase, nanocrystalline materials, the prediction being in good agreement with the results in the literature. Further, the established method is extended tosimulate the constitutive relations of porous and possible multi-phase nanocrystalline materials with small plastic deformation in conjunction with the secant-moduli approach and iso-strain assumption. Comparisons between the experimental grain size and porosity dependent mechanical data and the corresponding predictions using the established model show that it appears to be capable of describing the time-independent mechanical behaviors for porous and multi-phase nanocrystalline materials in a small plastic strain range. Further discussion on the modification factor, the advantages and limitations of the model developed were present.

  19. Porous MgO material with ultrahigh surface area as the matrix for phase change composite

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Yonggan; Shao, Xiankun; Liu, Tongxuan [School of Materials Science and Engineering, Anhui University of Science and Technology, Huainan, Anhui 232001 (China); Li, Benxia, E-mail: libx@mail.ustc.edu.cn [School of Materials Science and Engineering, Anhui University of Science and Technology, Huainan, Anhui 232001 (China); Nie, Shibin, E-mail: nsb@mail.ustc.edu.cn [School of Energy Resources and Safety, Anhui University of Science and Technology, Huainan, Anhui 232001 (China)

    2015-03-20

    Highlights: • Porous MgO material with ultrahigh surface area was synthesized. • A composite PCM was prepared from PEG-1000 and the porous MgO. • The phase change temperatures and enthalpy of the composite were measured. • The composite PCM performed good shape-stabilized property. - Abstract: Mesoporous magnesium oxide (MgO) material was synthesized using an integration of the evaporation-induced surfactant assembly and magnesium nitrate pyrolysis. The as-prepared MgO material is well crystalline, and possesses three-dimensional interconnected mesopores and a surface area as high as 596 m{sup 2}/g. Using the porous MgO as a matrix and polyethylene glycol (PEG-1000) as the functional phase for heat energy storage, a shape-stabilized phase change composite of PEG/MgO was fabricated by an easy impregnation method. In the composite, mesoporous MgO material provides structural strength and prevents the leakage of the molten PEG during the phase change process. The compositions and microstructures of the PEG/MgO composite were determined by Fourier transformation infrared spectroscope (FT-IR), X-ray diffractometer (XRD), scanning electronic microscope (SEM) and thermogravimetric analyzer (TGA), respectively. The phase change properties of the PEG/MgO composite were determined by differential scanning calorimeter (DSC). The high heat-energy storage capability and good thermal stability of the composite enable it extensive applications in the future.

  20. Dynamically vulcanized biobased polylactide/natural rubber blend material with continuous cross-linked rubber phase.

    Science.gov (United States)

    Chen, Yukun; Yuan, Daosheng; Xu, Chuanhui

    2014-03-26

    We prepared a biobased material, dynamically vulcanized polylactide (PLA)/natural rubber (NR) blend in which the cross-linked NR phase owned a continuous network-like dispersion. This finding breaks the traditional concept of a sea-island morphology formed after dynamic vulcanization of the blends. The scan electron microscopy and dissolution/swell experiments provided the direct proof of the continuous cross-linked NR phase. This new biobased PLA/NR blend material with the novel structure is reported for the first time in the field of dynamic vulcanization and shows promise for development for various functional applications.

  1. Embedded binary eutectic alloy nanostructures: a new class of phase change materials.

    Science.gov (United States)

    Shin, S J; Guzman, J; Yuan, C-W; Liao, Christopher Y; Boswell-Koller, Cosima N; Stone, P R; Dubon, O D; Minor, A M; Watanabe, Masashi; Beeman, Jeffrey W; Yu, K M; Ager, J W; Chrzan, D C; Haller, E E

    2010-08-11

    Phase change materials are essential to a number of technologies ranging from optical data storage to energy storage and transport applications. This widespread interest has given rise to a substantial effort to develop bulk phase change materials well suited for desired applications. Here, we suggest a novel and complementary approach, the use of binary eutectic alloy nanoparticles embedded within a matrix. Using GeSn nanoparticles embedded in silica as an example, we establish that the presence of a nanoparticle/matrix interface enables one to stabilize both nanobicrystal and homogeneous alloy morphologies. Further, the kinetics of switching between the two morphologies can be tuned simply by altering the composition.

  2. Nanoelectronic programmable synapses based on phase change materials for brain-inspired computing.

    Science.gov (United States)

    Kuzum, Duygu; Jeyasingh, Rakesh G D; Lee, Byoungil; Wong, H-S Philip

    2012-05-09

    Brain-inspired computing is an emerging field, which aims to extend the capabilities of information technology beyond digital logic. A compact nanoscale device, emulating biological synapses, is needed as the building block for brain-like computational systems. Here, we report a new nanoscale electronic synapse based on technologically mature phase change materials employed in optical data storage and nonvolatile memory applications. We utilize continuous resistance transitions in phase change materials to mimic the analog nature of biological synapses, enabling the implementation of a synaptic learning rule. We demonstrate different forms of spike-timing-dependent plasticity using the same nanoscale synapse with picojoule level energy consumption.

  3. Development of phase change materials based microencapsulated technology for buildings: A review

    Energy Technology Data Exchange (ETDEWEB)

    Tyagi, V.V.; Kaushik, S.C. [Centre for Energy Studies, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016 (India); Tyagi, S.K. [School of Infrastructure Technology and Resource Management, Shri Mata Vaishno Devi University, Katra 182320, J and K (India); Akiyama, T. [Center for Advanced Research of Energy Conversion Materials, Hokkaido University, Kita 13, Nishi 8, Kita-ku, Sapporo 060-86283 (Japan)

    2011-02-15

    Thermal energy storage (TES) systems using phase change material (PCM) have been recognized as one of the most advanced energy technologies in enhancing the energy efficiency and sustainability of buildings. Now the research is focus on suitable method to incorporate PCMs with building. There are several methods to use phase change materials (PCMs) in thermal energy storage (TES) for different applications. Microencapsulation is one of the well known and advanced technologies for better utilization of PCMs with building parts, such as, wall, roof and floor besides, within the building materials. Phase change materials based microencapsulation for latent heat thermal storage (LHTS) systems for building application offers a challenging option to be employed as effective thermal energy storage and a retrieval device. Since the particular interest in using microencapsulation PCMs for concrete and wall/wallboards, the specific research efforts on both subjects are reviewed separately. This paper presents an overview of the previous research work on microencapsulation technology for thermal energy storage incorporating the phase change materials (PCMs) in the building applications, along with few useful conclusive remarks concluded from the available literature. (author)

  4. Characterization of a lime-pozzolan plaster containing phase change material

    Energy Technology Data Exchange (ETDEWEB)

    Pavlíková, Milena; Pavlík, Zbyšek; Trník, Anton; Pokorný, Jaroslav; Černý, Robert [Department of Materials Engineering and Chemistry, Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29 Prague (Czech Republic)

    2015-03-10

    A PCM (Phase Change Material) modified lime-pozzolan plaster for improvement of thermal energy storage of building envelopes is studied in the paper. The investigated plaster is composed of lime hydrate, pozzolan admixture based on metakaolin and mudstone, silica sand, water and paraffin wax encapsulated in polymer capsule. The reference plaster without PCM application is studied as well. The analyzed materials are characterized by bulk density, matrix density, total open porosity, compressive strength and pore size distribution. The temperature of phase change, heat of fusion and crystallization are studied using DSC (Difference Scanning Calorimetry) analysis performed in air atmosphere. In order to get information on materials hygrothermal performance, determination of thermal and hygric properties is done in laboratory conditions. Experimental data reveal a substantial improvement of heat storage capacity of PCM-modified plaster as compared to the reference material without PCM.

  5. Density functional theory study of phase stability and defect thermodynamics in iron-oxyhydroxide mineral materials

    Science.gov (United States)

    Pinney, Nathan Douglas

    Due to their high surface area and reactivity toward a variety of heavy metal and oxyanion species of environmental concern, Fe-(oxyhydr)oxide materials play an important role in the geochemical fate of natural and anthropogenic contaminants in soils, aquifers and surface water environments worldwide. In this research, ab initio simulations describe the bulk structure, magnetic properties, and relative phase stability of major Fe-(oxyhydr)oxide materials, including hematite, goethite, lepidocrocite, and ferrihydrite.These bulk models are employed in further studies of point defect and alloy/dopant thermodynamics in these materials, allowing construction of a phase stability model that better replicates the structure and composition of real materials. Li + adsorption at the predominant goethite (101) surface is simulated using ab initio methods, offering energetic and structural insight into the binding mechanisms of metal cations over a range of surface protonation conditions.

  6. Study on polyethylene glycol/epoxy resin composite as a form-stable phase change material

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Yutang; Kang, Huiying; Wang, Weilong; Liu, Hong; Gao, Xuenong [The Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education, South China University of Technology, Guangzhou 510640 (China)

    2010-12-15

    Form-stable polyethylene glycol (PEG)/epoxy resin (EP) composite as a novel phase change material (PCM) was prepared using casting molding method. In this new material, PEG acts as the latent heat storage material and EP polymer serves as the supporting material, which provides structural strength and prevents the leakage of the melted PEG. The structure and morphology of the novel composite were observed using Fourier transformation infrared spectroscope (FTIR) and scanning electronic microscope (SEM). The thermo-mechanical property and transition behavior were characterized by polarizing optical microscope (POM), static thermo-mechanical analysis (TMA) and differential scanning calorimeter (DSC). The experimental results show that, as a result of the physical tangled function of the epoxy resin carrier to the PEG segment, the composite macroscopically presents the solid-solid phase change characteristic. (author)

  7. Study on polyethylene glycol/epoxy resin composite as a form-stable phase change material

    Energy Technology Data Exchange (ETDEWEB)

    Fang Yutang, E-mail: ppytfang@scut.edu.c [Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education, South China University of Technology, Guangzhou 510640 (China); Kang Huiying; Wang Weilong; Liu Hong; Gao Xuenong [Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education, South China University of Technology, Guangzhou 510640 (China)

    2010-12-15

    Form-stable polyethylene glycol (PEG)/epoxy resin (EP) composite as a novel phase change material (PCM) was prepared using casting molding method. In this new material, PEG acts as the latent heat storage material and EP polymer serves as the supporting material, which provides structural strength and prevents the leakage of the melted PEG. The structure and morphology of the novel composite were observed using Fourier transformation infrared spectroscope (FTIR) and scanning electronic microscope (SEM). The thermo-mechanical property and transition behavior were characterized by polarizing optical microscope (POM), static thermo-mechanical analysis (TMA) and differential scanning calorimeter (DSC). The experimental results show that, as a result of the physical tangled function of the epoxy resin carrier to the PEG segment, the composite macroscopically presents the solid-solid phase change characteristic.

  8. Basic Principles and Utilization Possibilities’ of Ultrasonic Phased Array in Material Nondestructive Evaluation

    OpenAIRE

    Ivo Cap; Klara Capova; Dagmar Faktorova

    2004-01-01

    The paper deals with the basic principles of operation and with the utilization possibilities of phased array (PA) in materials nondestructive testing (NDT). The first part deals with description of PA arrangement modes, which enable to generate, focus and steer the ultrasonic beem. The second part deals with the description of electromagnetic acoustic transducer PA operation. The last part deals with the description of the utilization of PA in nondestructive testing of conductive materials a...

  9. Energy Storage Properties of Phase Change Materials Prepared from PEG/CPP

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    New kinds of solid-solid phase change materials have been prepared in our laboratory.In these materials, the rigid polymer chlorinated polypropylene is taken as skeletons and the flexible polymer polyethylene glycol 6000 and polyethylene glycol 10000 are taken as functional chains. Results show that chlorinated polypropylene grafted by polyethylene glycol 10000 has greater enthalpy than chlorinated polypropylene grafted by polyethylene glycol 6000.

  10. RIMS International Conference : Mathematical Challenges in a New Phase of Materials Science

    CERN Document Server

    Kotani, Motoko

    2016-01-01

    This volume comprises eight papers delivered at the RIMS International Conference "Mathematical Challenges in a New Phase of Materials Science", Kyoto, August 4–8, 2014. The contributions address subjects in defect dynamics, negatively curved carbon crystal, topological analysis of di-block copolymers, persistence modules, and fracture dynamics. These papers highlight the strong interaction between mathematics and materials science and also reflect the activity of WPI-AIMR at Tohoku University, in which collaborations between mathematicians and experimentalists are actively ongoing.

  11. Intergranular and inter-phased boundaries in the materials; Joints intergranulaires et interphases dans les materiaux

    Energy Technology Data Exchange (ETDEWEB)

    Aslanides, A. [Electricite de France, Dept. CIMA, 77 - Moret sur Loing (France); Backhaus-Ricoult, M. [Centre d' Etudes de Chimie metallurgique, 94 - Vitry-sur-Seine (France); Bayle-Guillemaud, P. [CEA Grenoble, Dept. de Recherche Fondamentale sur la Matiere Condensee, 38 (France)] [and others

    2000-07-01

    This document collects the abstracts of the talks presented during the colloquium J2IM on the intergranular and inter-phased boundaries in the materials. Around the themes of the interfaces behaviour and grain boundaries defects in materials, these days dealt with the microstructure behaviour in many domains such as the interfaces in batteries, the irradiation damages and the special case of the fuel-cladding interactions, the stressed interfaces, the alumina or silicon carbides substrates. (A.L.B.)

  12. A Review On Free Cooling Through Heat Pipe by Using Phase Change Materials

    Directory of Open Access Journals (Sweden)

    A.S.Futane ,

    2011-06-01

    Full Text Available Thermal energy storage is renewable source of energy to develop energy storage system, which minimize environmental impact such as ozone depletion and global warming. Thermal energy can be stored as latent heat which is latter use when substance changes from one phase to another phase by either freezing or melting. Now a days need of refrigeration and air conditioning has been increased, which can be achieved by free cooling, for this various substances are use, depending upon required temperature. Phase change materials are one of the substances having low temperature of melting and solidification.

  13. On entropy change measurements around first order phase transitions in caloric materials

    Science.gov (United States)

    Caron, Luana; Doan, Nguyen Ba; Ranno, Laurent

    2017-02-01

    In this work we discuss the measurement protocols for indirect determination of the isothermal entropy change associated with first order phase transitions in caloric materials. The magneto-structural phase transitions giving rise to giant magnetocaloric effects in Cu-doped MnAs and FeRh are used as case studies to exemplify how badly designed protocols may affect isothermal measurements and lead to incorrect entropy change estimations. Isothermal measurement protocols which allow correct assessment of the entropy change around first order phase transitions in both direct and inverse cases are presented.

  14. Nature of defects and gap states in GeTe model phase change materials

    Science.gov (United States)

    Huang, B.; Robertson, J.

    2012-03-01

    The electrical storage mechanism in GeSbTe phase change materials is discussed in terms of their gap states using GeTe as a model system. The lowest energy defect in crystalline rhombohedral GeTe phase is the Ge vacancy, because it reconstructs along the resonant bonding directions. The lowest energy in amorphous GeTe is the divalent Te atom, which creates overlapping band-tail states that pin Fermi level EF near midgap. In contrast, the lowest cost defect in disordered phase in GeSbTe superlattices is the Te interstitial whose negative correlation energy pins EF near midgap.

  15. Enhancing heat capacity of colloidal suspension using nanoscale encapsulated phase-change materials for heat transfer.

    Science.gov (United States)

    Hong, Yan; Ding, Shujiang; Wu, Wei; Hu, Jianjun; Voevodin, Andrey A; Gschwender, Lois; Snyder, Ed; Chow, Louis; Su, Ming

    2010-06-01

    This paper describes a new method to enhance the heat-transfer property of a single-phase liquid by adding encapsulated phase-change nanoparticles (nano-PCMs), which absorb thermal energy during solid-liquid phase changes. Silica-encapsulated indium nanoparticles and polymer-encapsulated paraffin (wax) nanoparticles have been made using colloid method, and suspended into poly-alpha-olefin (PAO) and water for potential high- and low-temperature applications, respectively. The shells prevent leakage and agglomeration of molten phase-change materials, and enhance the dielectric properties of indium nanoparticles. The heat-transfer coefficients of PAO containing indium nanoparticles (30% by mass) and water containing paraffin nanoparticles (10% by mass) are 1.6 and 1.75 times higher than those of corresponding single-phase fluids. The structural integrity of encapsulation allows repeated use of such nanoparticles for many cycles in high heat generating devices.

  16. PHASE I MATERIALS PROPERTY DATABASE DEVELOPMENT FOR ASME CODES AND STANDARDS

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Weiju [ORNL; Lin, Lianshan [ORNL

    2013-01-01

    To support the ASME Boiler and Pressure Vessel Codes and Standard (BPVC) in modern information era, development of a web-based materials property database is initiated under the supervision of ASME Committee on Materials. To achieve efficiency, the project heavily draws upon experience from development of the Gen IV Materials Handbook and the Nuclear System Materials Handbook. The effort is divided into two phases. Phase I is planned to deliver a materials data file warehouse that offers a depository for various files containing raw data and background information, and Phase II will provide a relational digital database that provides advanced features facilitating digital data processing and management. Population of the database will start with materials property data for nuclear applications and expand to data covering the entire ASME Code and Standards including the piping codes as the database structure is continuously optimized. The ultimate goal of the effort is to establish a sound cyber infrastructure that support ASME Codes and Standards development and maintenance.

  17. SBIR and STTR Program for Assistive Technology Device Development: Evaluation of Impact Using an ICF-Based Classification

    Science.gov (United States)

    Bauer, Stephen M.; Arthanat, Sajay

    2010-01-01

    The purpose of this paper was to evaluate the impact of Small Business Innovation Research (SBIR) and Small Business Technology Transfer Research (STTR) grant programs of 5 federal agencies National Institutes of Health (NIH), National Science Foundation (NSF), U.S. Department of Education (USDE), U.S. Department of Agriculture (USDA), and…

  18. Nanoscale Phase Immiscibility in High-ZT Bulk Lead Telluride Thermoelectric Materials

    Science.gov (United States)

    Girard, Steven Neal

    Renewable energy initiatives have increased interest in thermoelectric materials as an option for inexpensive and environmentally friendly waste heat-to-power generation. Unfortunately, low efficiencies have limited their wide-scale utilization. This work describes the synthesis and characterization of bulk nanostructured thermoelectric materials wherein natural phase immiscibility is manipulated to selectively generate nanoscale inclusions of a second phase that improve their efficiency through reductions in lattice thermal conductivity. The PbTe-PbS system exhibits natural phase separation by nucleation and growth or spinodal decomposition phase transformations depending on composition and temperature treatment. Through rapid quenching, nearly ideal solid solution alloys of PbTe-PbS are observed by powder X-ray diffraction. However, characterization by solid-state NMR and IR reflectivity show that solid solutions are obtained for rapidly quenched samples within the nucleation and growth region of the phase diagram, but samples within the spinodal decomposition region exhibit very slight phase immiscibility. We report the temperatures of phase separation using high temperature powder X-ray diffraction. Microscopy reveals that phase separation in PbTe-PbS naturally produces nanoinclusions. A decrease in lattice thermal conductivity is observed as a result of the solid solution-to-nanostructured phase transformation in this materials system, increasing thermoelectric figure of merit. Sn addition to PbTe-PbS produces a pseudobinary system of PbTe-PbSnS 2. This materials system produces microscale lamellae that effectively reduce lattice thermal conductivity. Unfortunately, the PbSnS2 inclusions also scatter electrons, reducing electrical conductivity and producing only a minimal increase in thermoelectric figure of merit. We additionally investigate PbSnS2 as prepared through Bridgman crystal growth. PbTe-PbS doped with Na appears to increase the kinetic rate of

  19. LIFE Materials: Phase Formation and Transformations in Transmutation Fuel Materials for the LIFE Engine Part I - Path Forward Volume 3

    Energy Technology Data Exchange (ETDEWEB)

    Turchi, P A; Kaufman, L; Fluss, M

    2008-12-19

    The current specifications of the LLNL fusion-fission hybrid proposal, namely LIFE, impose severe constraints on materials, and in particular on the nuclear fissile or fertile nuclear fuel and its immediate environment. This constitutes the focus of the present report with special emphasis on phase formation and phase transformations of the transmutation fuel and their consequences on particle and pebble thermal, chemical, and mechanical integrities. We first review the work that has been done in recent years to improve materials properties under the Gen-IV project, and with in particular applications to HTGR and MSR, and also under GNEP and AFCI in the USA. Our goal is to assess the nuclear fuel options that currently exist together with their issues. Among the options, it is worth mentioning TRISO, IMF, and molten salts. The later option will not be discussed in details since an entire report (Volume 8 - Molten-salt Fuels) is dedicated to it. Then, in a second part, with the specific LIFE specifications in mind, the various fuel options with their most critical issues are revisited with a path forward for each of them in terms of research, both experimental and theoretical. Since LIFE is applicable to very high burn-up of various fuels, distinctions will be made depending on the mission, i.e., energy production or incineration. Finally a few conclusions are drawn in terms of the specific needs for integrated materials modeling and the in depth knowledge on time-evolution thermo-chemistry that controls and drastically affects the performance of the nuclear materials and their immediate environment. Although LIFE demands materials that very likely have not yet been fully optimized, the challenges are not insurmountable, and a well concerted experimental-modeling effort should lead to dramatic advances that should well serve other fission programs such as Gen-IV, GNEP, AFCI as well as the international fusion program, ITER.

  20. Analysis of Phase Separation in High Performance PbTe–PbS Thermoelectric Materials

    Energy Technology Data Exchange (ETDEWEB)

    Girard, Steven N. [Northwestern University; Schmidt-Rohr, Klaus [Ames Laboratory; Chasapis, Thomas C. [Northwestern University; Hatzikraniotis, Euripides [Aristotle University of Thessaloniki; Njegic, B. [Ames Laboratory; Levin, E. M. [Ames Laboratory; Rawal, A. [Ames Laboratory; Paraskevopoulos, Konstantios M. [Aristotle University of Thessaloniki; Kanatzidis, Mercouri G. [Northwestern University

    2013-02-11

    Phase immiscibility in PbTe–based thermoelectric materials is an effective means of top-down synthesis of nanostructured composites exhibiting low lattice thermal conductivities. PbTe1-x Sx thermoelectric materials can be synthesized as metastable solid solution alloys through rapid quenching. Subsequent post-annealing induces phase separation at the nanometer scale, producing nanostructures that increase phonon scattering and reduce lattice thermal conductivity. However, there has yet to be any study investigating in detail the local chemical structure of both the solid solution and nanostructured variants of this material system. Herein, quenched and annealed (i.e., solid solution and phase-separated) samples of PbTe–PbS are analyzed by in situ high-resolution synchrotron powder X-ray diffraction, solid-state 125Te nuclear magnetic resonance (NMR), and infrared (IR) spectroscopy analysis. For high concentrations of PbS in PbTe, e.g., x >16%, NMR and IR analyses reveal that rapidly quenched samples exhibit incipient phase separation that is not detected by state-of-the-art synchrotron X-ray diffraction, providing an example of a PbTe thermoelectric “alloy” that is in fact phase inhomogeneous. Thermally-induced PbS phase separation in PbTe–PbS occurs close to 200 °C for all compositions studied, and the solubility of the PbS phase in PbTe at elevated temperatures >500 °C is reported. The findings of this study suggest that there may be a large number of thermoelectric alloy systems that are phase inhomogeneous or nanostructured despite adherence to Vegard's Law of alloys, highlighting the importance of careful chemical characterization to differentiate between thermoelectric alloys and composites.

  1. Energy Saving Potentials of Phase Change Materials Applied to Lightweight Building Envelopes

    Directory of Open Access Journals (Sweden)

    Yoon-Bok Seong

    2013-10-01

    Full Text Available Phase change materials (PCMs have been considered as an innovative technology that can reduce the peak loads and heating, ventilating and air conditioning (HVAC energy consumption in buildings. Basically they are substances capable of storing or releasing thermal energy as latent heat. Because the amount of latent heat absorbed or released is much larger than the sensible heat, the application of PCMs in buildings has significant potential to reduce energy consumption. However, because each PCM has its own phase change temperature, which is the temperature at which latent heat is absorbed or released, it is important to use an appropriate PCM for the purpose of building envelope design. Therefore, this paper aims to investigate the energy saving potentials in buildings when various PCMs with different phase change temperatures are applied to a lightweight building envelope by analyzing the thermal load characteristics. As results, the annual heating load increased at every phase change temperature, but the peak heating load decreased by 3.19% with heptadecane (phase change temperature 21 °C, and the lowest indoor temperature increased by 0.86 °C with heptadecane (phase change temperature 21 °C. The annual cooling load decreased by 1.05% with dodecanol (phase change temperature 24 °C, the peak cooling load decreased by 1.30% with octadecane (phase change temperature 29 °C, and the highest indoor temperature dropped by 0.50 °C with octadecane (phase change temperature 29 °C. When the night ventilation was applied to the building HVAC system for better passive cooling performance, the annual cooling load decreased by 9.28% with dodecanol (phase change temperature 24 °C, the peak load decreased by 11.33% with octadecane (phase change temperature 29 °C, and the highest indoor temperature dropped by 0.85 °C with octadecane (phase change temperature 29 °C.

  2. Basic Principles and Utilization Possibilities’ of Ultrasonic Phased Array in Material Nondestructive Evaluation

    Directory of Open Access Journals (Sweden)

    Dagmar Faktorova

    2004-01-01

    Full Text Available The paper deals with the basic principles of operation and with the utilization possibilities of phased array (PA in materials nondestructive testing (NDT. The first part deals with description of PA arrangement modes, which enable to generate, focus and steer the ultrasonic beem. The second part deals with the description of electromagnetic acoustic transducer PA operation. The last part deals with the description of the utilization of PA in nondestructive testing of conductive materials and the advantages of PA utilization in inhomogeneous materials NDT.

  3. Relation between bandgap and resistance drift in amorphous phase change materials.

    Science.gov (United States)

    Rütten, Martin; Kaes, Matthias; Albert, Andreas; Wuttig, Matthias; Salinga, Martin

    2015-12-01

    Memory based on phase change materials is currently the most promising candidate for bridging the gap in access time between memory and storage in traditional memory hierarchy. However, multilevel storage is still hindered by the so-called resistance drift commonly related to structural relaxation of the amorphous phase. Here, we present the temporal evolution of infrared spectra measured on amorphous thin films of the three phase change materials Ag4In3Sb67Te26, GeTe and the most popular Ge2Sb2Te5. A widening of the bandgap upon annealing accompanied by a decrease of the optical dielectric constant ε∞ is observed for all three materials. Quantitative comparison with experimental data for the apparent activation energy of conduction reveals that the temporal evolution of bandgap and activation energy can be decoupled. The case of Ag4In3Sb67Te26, where the increase of activation energy is significantly smaller than the bandgap widening, demonstrates the possibility to identify new phase change materials with reduced resistance drift.

  4. The behavior of self-compacting concrete containing micro-encapsulated Phase Change Materials

    NARCIS (Netherlands)

    Hunger, M.; Entrop, A.G.; Mandilaras, I.; Brouwers, H.J.H.; Founti, M.

    2009-01-01

    In order to come to a sustainable built environment the construction industry requires new energy saving concepts. One concept is to use Phase Change Materials (PCM), which have the ability to absorb and to release thermal energy at a specific temperature. This paper presents a set of experiments us

  5. Micromechanical Analyses of Debonding and Matrix Cracking in Dual-Phase Materials

    DEFF Research Database (Denmark)

    Legarth, Brian Nyvang; Yang, Qingda

    2016-01-01

    Failure in elastic dual-phase materials under transverse tension is studied numerically. Cohesive zones represent failure along the interface and the augmented finite element method (A-FEM) is used for matrix cracking. Matrix cracks are formed at an angle of 55 deg - 60 deg relative to the loading...

  6. Optimal design variable considerations in the use of phase change materials in indirect evaporative cooling

    Science.gov (United States)

    Chilakapaty, Ankit Paul

    The demand for sustainable, energy efficient and cost effective heating and cooling solutions is exponentially increasing with the rapid advancement of computation and information technology. Use of latent heat storage materials also known as phase change materials (PCMs) for load leveling is an innovative solution to the data center cooling demands. These materials are commercially available in the form of microcapsules dispersed in water, referred to as the microencapsulated phase change slurries and have higher heat capacity than water. The composition and physical properties of phase change slurries play significant role in energy efficiency of the cooling systems designed implementing these PCM slurries. Objective of this project is to study the effect of PCM particle size, shape and volumetric concentration on overall heat transfer potential of the cooling systems designed with PCM slurries as the heat transfer fluid (HTF). In this study uniform volume heat source model is developed for the simulation of heat transfer potential using phase change materials in the form of bulk temperature difference in a fully developed flow through a circular duct. Results indicate the heat transfer potential increases with PCM volumetric concentration with gradually diminishing returns. Also, spherical PCM particles offer greater heat transfer potential when compared to cylindrical particles. Results of this project will aid in efficient design of cooling systems based on PCM slurries.

  7. Nature of the first-order magnetic phase transition in giant-magnetocaloric materials

    NARCIS (Netherlands)

    Yibole

    2016-01-01

    This thesis reports on advanced characterizations of giant magnetocaloric materials that show a first order magnetic phase transition (FOMT). The results are of great interest not only for the design of new magnetic refrigerants, but also for a better understanding of the FOMT. This thesis paves the

  8. Structural semiconductor-to-semimetal phase transition in two-dimensional materials induced by electrostatic gating.

    Science.gov (United States)

    Li, Yao; Duerloo, Karel-Alexander N; Wauson, Kerry; Reed, Evan J

    2016-01-01

    Dynamic control of conductivity and optical properties via atomic structure changes is of technological importance in information storage. Energy consumption considerations provide a driving force towards employing thin materials in devices. Monolayer transition metal dichalcogenides are nearly atomically thin materials that can exist in multiple crystal structures, each with distinct electrical properties. By developing new density functional-based methods, we discover that electrostatic gating device configurations have the potential to drive structural semiconductor-to-semimetal phase transitions in some monolayer transition metal dichalcogenides. Here we show that the semiconductor-to-semimetal phase transition in monolayer MoTe2 can be driven by a gate voltage of several volts with appropriate choice of dielectric. We find that the transition gate voltage can be reduced arbitrarily by alloying, for example, for Mo(x)W(1-x)Te2 monolayers. Our findings identify a new physical mechanism, not existing in bulk materials, to dynamically control structural phase transitions in two-dimensional materials, enabling potential applications in phase-change electronic devices.

  9. Non-Toxic, Non-Flammable, -80 C Phase Change Materials

    Science.gov (United States)

    Cutbirth, J. Michael

    2013-01-01

    The objective of this effort was to develop a non-toxic, non-flammable, -80 C phase change material (PCM) to be used in NASA's ICEPAC capsules for biological sample preservation in flight to and from Earth orbit. A temperature of about -68 C or lower is a critical temperature for maintaining stable cell, tissue, and cell fragment storage.

  10. Non-binary Colour Modulation for Display Device Based on Phase Change Materials

    Science.gov (United States)

    Ji, Hong-Kai; Tong, Hao; Qian, Hang; Hui, Ya-Juan; Liu, Nian; Yan, Peng; Miao, Xiang-Shui

    2016-12-01

    A reflective-type display device based on phase change materials is attractive because of its ultrafast response time and high resolution compared with a conventional display device. This paper proposes and demonstrates a unique display device in which multicolour changing can be achieved on a single device by the selective crystallization of double layer phase change materials. The optical contrast is optimized by the availability of a variety of film thicknesses of two phase change layers. The device exhibits a low sensitivity to the angle of incidence, which is important for display and colour consistency. The non-binary colour rendering on a single device is demonstrated for the first time using optical excitation. The device shows the potential for ultrafast display applications.

  11. Preparation and Properties of Paraffin/TiO2/Active-carbon Composite Phase Change Materials

    Directory of Open Access Journals (Sweden)

    HAO Yong-gan

    2016-11-01

    Full Text Available A novel composite phase change materials (PCMs of paraffin/TiO2/active-carbon was prepared by a microemulsion method, where paraffin acted as a PCM and titanium dioxide (TiO2 as matrix material, and a small amount of active carbon was added to improve the thermal conductivity. The compositions, morphology and thermal properties of the paraffin/TiO2/active-carbon composite PCMs were characterized by XRD, SEM, TGA and DSC respectively. The shape stability during phase change process of this composite was also tested. The results show that paraffin is well encapsulated by TiO2 matrix, and thus exhibiting excellent shape-stabilized phase change feature. Besides, this composite PCM also presents superhydrophobic property. Therefore, these multifunctional features will endow PCMs with important application potential in energy efficient buildings.

  12. Penn gap rule in phase-change memory materials: No clear evidence for resonance bonds

    Science.gov (United States)

    Shimakawa, K.; Střižik, L.; Wagner, T.; Frumar, M.

    2015-04-01

    Although a proposal of resonance bonds in crystalline phase-change materials based on the GeSbTe system has been provided, we do not find any clear evidence in favor of the proposal. The ellipsometric study demonstrates that a change in the high frequency dielectric constant ɛ∞ between the amorphous and crystalline phases is only scaled by the average bandgap (the Penn gap rule). Even for a pure antimony film, regarded as a prototype resonance bonding material, ɛ∞ was found to follow the Penn gap rule. Experimentally, we did not find any evidence of a significant change in the optical transition matrix element during the phase change, which is necessary to support the idea of resonance bonds.

  13. Penn gap rule in phase-change memory materials: No clear evidence for resonance bonds

    Directory of Open Access Journals (Sweden)

    K. Shimakawa

    2015-04-01

    Full Text Available Although a proposal of resonance bonds in crystalline phase-change materials based on the GeSbTe system has been provided, we do not find any clear evidence in favor of the proposal. The ellipsometric study demonstrates that a change in the high frequency dielectric constant ε∞ between the amorphous and crystalline phases is only scaled by the average bandgap (the Penn gap rule. Even for a pure antimony film, regarded as a prototype resonance bonding material, ε∞ was found to follow the Penn gap rule. Experimentally, we did not find any evidence of a significant change in the optical transition matrix element during the phase change, which is necessary to support the idea of resonance bonds.

  14. X-Ray Diffraction Phase Analyses for Granulated and Sintered Ceramic Materials

    Directory of Open Access Journals (Sweden)

    Suminar Pratapa

    2007-11-01

    Full Text Available One basic problematic aspect in x-ray diffraction phase analysis is microabsorption effect which may arise from the size of the crystallite phases. Complication of the problem may intensify in sintered ceramic materials where milling of the samples is not simple. We report the Rietveld x-ray diffraction phase analysis of MgO-α-Al2O3 powder mixtures with phase content ratio of 1:1 by weight and MgO-Y2O3 sintered ceramic composites with Y2O3 contents of 10%, 20% and 30% by weight. The mixtures were pre-sintered at 1000°C for 2 hours and then milled while the composites were sintered at 1550°C for 3 hours. The phase composition analysis was done using Rietica, a non-commercial Rietveld method-based software. Relative and absolute phase compositions were examined and results showed that there was a significant amount of phase composition bias resulted from the examination. For the powder mixture, milling can reduce microabsorption effect and hence the calculation bias. For the ceramic composite where milling is almost impossible, additional of Y2O3 caused smaller crystallite size of MgO, so that composition bias is smaller in composites with higher Y2O3 content. A mathematical model is proposed to provide more acceptable phase composition results.

  15. Advanced phase change materials and systems for solar passive heating and cooling of residential buildings

    Energy Technology Data Exchange (ETDEWEB)

    Salyer, I.O.; Sircar, A.K.; Dantiki, S.

    1988-01-01

    During the last three years under the sponsorship of the DOE Solar Passive Division, the University of Dayton Research Institute (UDRI) has investigated four phase change material (PCM) systems for utility in thermal energy storage for solar passive heating and cooling applications. From this research on the basis of cost, performance, containment, and environmental acceptability, we have selected as our current and most promising series of candidate phase change materials, C-15 to C-24 linear crystalline alkyl hydrocarbons. The major part of the research during this contract period was directed toward the following three objectives. Find, test, and develop low-cost effective phase change materials (PCM) that melt and freeze sharply in the comfort temperature range of 73--77{degree}F for use in solar passive heating and cooling of buildings. Define practical materials and processes for fire retarding plasterboard/PCM building products. Develop cost-effective methods for incorporating PCM into building construction materials (concrete, plasterboard, etc.) which will lead to the commercial manufacture and sale of PCM-containing products resulting in significant energy conservation.

  16. Electronic Structure and Spin Configuration Trends of Single Transition Metal Impurity in Phase Change Material

    Science.gov (United States)

    Li, H.; Pei, J.; Shi, L. P.

    2016-10-01

    Fe doped phase change material GexSbyTez has shown experimentally the ability to alter its magnetic properties by phase change. This engineered spin degree of freedom into the phase change material offers the possibility of logic devices or spintronic devices where they may enable fast manipulation of ferromagnetism by a phase change mechanism. The electronic structures and spin configurations of isolated transition metal dopant in phase change material (iTM-PCM) is important to understand the interaction between localized metal d states and the unique delocalized host states of phase change material. Identifying an impurity center that has, in isolation, a nonvanishing magnetic moment is the first step to study the collective magnetic ordering, which originates from the interaction among close enough individual impurities. Theoretical description of iTM-PCM is challenging. In this work, we use a screened exchange hybrid functional to study the single 3d transition metal impurity in crystalline GeTe and GeSb2Te4. By curing the problem of local density functional (LDA) such as over-delocalization of the 3d states, we find that Fe on the Ge/Sb site has its majority d states fully occupied while its minority d states are empty, which is different from the previously predicted electronic configuration by LDA. From early transition metal Cr to heavier Ni, the majority 3d states are gradually populated until fully occupied and then the minority 3d states begin to be filled. Interpretive orbital interaction pictures are presented for understanding the local and total magnetic moments.

  17. Microencapsulation of coco fatty acid mixture for thermal energy storage with phase change material

    Energy Technology Data Exchange (ETDEWEB)

    Ozonur, Y.; Mazman, M.; Paksoy, H.O.; Evilya, H. [Cukurova University, Adana (Turkey). Dept. of Chemistry

    2005-07-01

    Thermal energy storage systems provide several alternatives for efficient energy use and energy conservation. Microcapsules of natural coco fatty acid mixture were prepared to be used as phase change materials for thermal energy storage. The coacervation technique was used for the microencapsulation process. Several alternatives for the capsule wall material were tried. The microcapsules were characterized according to their geometric profiles, phase transition temperatures, mean particle sizes, chemical stabilities, and their thermal cycling. The diameters of microcapsules prepared in this study were about 1 mm. Coco fatty acid mixtures have kept their geometrical profiles even after 50 thermal cycles for melting and freezing operations in temperature range from 22 to 34{sup o}C. It was found that gelatin+gum Arabic mixture was the best wall material for microencapsulating coco fatty acid mixtures. (author)

  18. 美国天基红外系统(SBIRS)的发展现状

    Institute of Scientific and Technical Information of China (English)

    侯振宁

    2002-01-01

    天基红外系统(SBIRS)是由美国空军研制的下一代天基红外监视系统,也美国国家导弹防御系统的一个组成部分.该系统的任务是:战略和战区导弹预警;跟踪从初始助推阶段到飞行中段的导弹目标,为导弹防御指示目标提供技术情报,增进战场态势感知.SBIRS在21世纪将为美国部队提供更准确、更及时的弹道导弹预警.

  19. SBIR Technology Applications to Space Communications and Navigation (SCaN)

    Science.gov (United States)

    Liebrecht, Phil; Eblen, Pat; Rush, John; Tzinis, Irene

    2010-01-01

    This slide presentation reviews the mission of the Space Communications and Navigation (SCaN) Office with particular emphasis on opportunities for technology development with SBIR companies. The SCaN office manages NASA's space communications and navigation networks: the Near Earth Network (NEN), the Space Network (SN), and the Deep Space Network (DSN). The SCaN networks nodes are shown on a world wide map and the networks are described. Two types of technologies are described: Pull technology, and Push technologies. A listing of technology themes is presented, with a discussion on Software defined Radios, Optical Communications Technology, and Lunar Lasercom Space Terminal (LLST). Other technologies that are being investigated are some Game Changing Technologies (GCT) i.e., technologies that offer the potential for improving comm. or nav. performance to the point that radical new mission objectives are possible, such as Superconducting Quantum Interference Filters, Silicon Nanowire Optical Detectors, and Auto-Configuring Cognitive Communications

  20. Si1Sb2Te3 phase change material for chalcogenide random access memory

    Institute of Scientific and Technical Information of China (English)

    Zhang Ting; Song Zhi-Tang; Liu Bo; Liu Wei-Li; Feng Song-Lin; Chen Bomy

    2007-01-01

    This paper investigated phase change Si1Sb2Te3 material for application of chalcogenide random access memory.Current-voltage performance was conducted to determine threshold current of phase change from amorphous phase to polycrystalline phase.The film holds a threshold current about 0.155 mA,which is smaller than the value 0.31 mA of Ge2Sb2Te5 film.Amorphous Si1Sb2Te3 changes to face-centred-cubic structure at~180°C and changes to hexagonal structure at~270°C.Annealing temperature dependent electric resistivity of Si1Sb2Te3 film was studied by four-point probe method.Data retention of the films was characterized as well.

  1. Processing And Properties Of MAX Phases – Based Materials Using SHS Technique

    Directory of Open Access Journals (Sweden)

    Chlubny L.

    2015-06-01

    Full Text Available Authors present results of works on the interesting new group of advanced ceramics called MAX phases – Ti-based ternary carbides and nitrides. They have an original layered structure involved highly anisotropic properties laying between ceramics and metals, with high elastic modulus, low hardness, very high fracture toughness and high electrical and heat conductivity. Using Self-Propagating High-Temperature Synthesis (SHS in the combustion regime it is possible to prepare MAX phases-rich powders that can be used as the precursors for preparation of dense MAX polycrystals by presureless sintering or hot-pressing. Different novel Ti-based phases with layered structures, namely: Ti3AlC2 and Ti2AlC have been synthesized in a combustion regime. The possibility of controlling of combustion phenomena for obtaining near single-phase products is discussed in details as well as some of properties of the materials tested as structure and functional ceramics.

  2. A hybrid phenomenological model for ferroelectroelastic ceramics. Part I: Single phased materials

    Science.gov (United States)

    Stark, S.; Neumeister, P.; Balke, H.

    2016-10-01

    In this part I of a two part series, a rate-independent hybrid phenomenological constitutive model applicable for single phased polycrystalline ferroelectroelastic ceramics is presented. The term "hybrid" refers to the fact that features from macroscopic phenomenological models and micro-electromechanical phenomenological models are combined. In particular, functional forms for a switching function and the Helmholtz free energy are assumed as in many macroscopic phenomenological models; and the volume fractions of domain variants are used to describe the internal material state, which is a key feature of micro-electromechanical phenomenological models. The approach described in this paper is an attempt to combine the advantages of macroscopic and micro-electromechanical material models. Its potential is demonstrated by comparison with experimental data for barium titanate. Finally, it is shown that the model for single phased materials cannot reproduce the material behavior of morphotropic PZT ceramics based on a realistic choice for the material parameters. This serves as a motivation for part II of the series, which deals with the modeling of morphotropic PZT ceramics taking into account the micro-structural specifics of these materials.

  3. A Super Cooled, Non-toxic, Non-flammable Phase Change Material Thermal Pack for Portable Life Support Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The concept development and test of a water-based, advanced Phase Change Material (PCM) heat sink is proposed. Utilizing a novel material choice for both an...

  4. A Super Cooled, Non-toxic, Non-flammable Phase Change Material Thermal Pack for Portable Life Support Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The continuation of concept development and test of a water-based, advanced Phase Change Material (PCM) heat sink is proposed. Utilizing a novel material choice for...

  5. A new analytical model for thermal stresses in multi-phase materials and lifetime prediction methods

    Institute of Scientific and Technical Information of China (English)

    Ladislav Ceniga

    2008-01-01

    Based on the fundamental equations of the mechanics of solid continuum, the paper employs an ana-lytical model for determination of elastic thermal stresses in isotropic continuum represented by periodically distributed spherical particles with different distributions in an infinite matrix, imaginarily divided into identical cells with dimen-sions equal to inter-particle distances, containing a central spherical particle with or without a spherical envelope on the particle surface. Consequently, the multi-particle-(envelope)-matrix system, as a model system regarding the analytical modelling, is applicable to four types of multi-phase mate-rials. As functions of the particle volume fraction v, the inter-particle distances d1, d2, d3 along three mutually per-pendicular axes, and the particle and envelope radii, R1 and Re, respectively, the thermal stresses within the cell, are originated during a cooling process as a consequence of the difference in thermal expansion coefficients of phases rep-resented by the matrix, envelope and particle. Analytical-(experimental)-computational lifetime prediction methods for multi-phase materials are proposed, which can be used in engineering with appropriate values of parameters of real multi-phase materials.

  6. Nanoengineered materials for liquid-vapour phase-change heat transfer

    Science.gov (United States)

    Cho, H. Jeremy; Preston, Daniel J.; Zhu, Yangying; Wang, Evelyn N.

    2016-12-01

    Liquid-vapour phase change is a useful and efficient process to transfer energy in nature, as well as in numerous domestic and industrial applications. Relatively recent advances in altering surface chemistry, and in the formation of micro- and nanoscale features on surfaces, have led to exciting improvements in liquid-vapour phase-change performance and better understanding of the underlying science. In this Review, we present an overview of the surface, thermal and material science to illustrate how new materials and designs can improve boiling and condensation. There are many parallels between boiling and condensation, such as nucleation of a phase and its departure from a surface; however, the particular set of challenges associated with each phenomenon results in different material designs used in different manners. We also discuss alternative techniques, such as introducing heterogeneous surface chemistry or direct real-time manipulation of the phase-change process, which can offer further control of heat-transfer processes. Finally, long-term robustness is essential to ensure reliability and feasibility but remains a key challenge.

  7. Electrical properties of Cr-doped Sb2Te3 phase change material

    Science.gov (United States)

    Wang, Qing; Liu, Bo; Xia, Yangyang; Zheng, Yonghui; Song, Sannian; Cheng, Yan; Song, Zhitang; Feng, Songlin

    2016-10-01

    Phase Change Memory (PCM) is regarded as one of the most promising candidates for the next-generation nonvolatile memory. Its storage medium, phase change material, has attracted continuous exploration. Sb2Te3 is a high-speed phase change material matrix with low crystallization temperature. Cr-doped Sb2Te3 (CST) films with suitable composition have been studied and proved to be a promising novel phase change material with high speed and good thermal stability. In this paper, detailed Rs-T characteristics and Hall characteristics of the CST films are studied. We find that, when more parts of the film crystallizes into the ordered structure, the activation energy for electrical conduction (Eσ) decreases, indicating that the semiconductor property is weakened. And with the increase of Cr-dopants, Eσ of the As-deposited (As-de) amorphous CST films decreases, thus the thermal stability of resistance is improved. Hall results show that Sb2Te3 and CST films are all in P-type. For As-de amorphous films, with the increase of Cr-dopants, the carrier mobility decreases all along, while the carrier density decreases at first and then increases. For the crystalline films, with the increase of Cr-dopants, the carrier mobility decreases, while the carrier density increases.

  8. Phase Change Material on Augmentation of Fresh Water Production Using Pyramid Solar Still

    Directory of Open Access Journals (Sweden)

    S. Ravishankara

    2013-10-01

    Full Text Available The augmentation of fresh water and increase in the solar still efficiency of a triangular pyramid is added with phase change material (PCM on the basin. Experimental studies were conducted and the effects of production of fresh water with and without PCM were investigated. Using paraffin as the PCM material, performance of the solar still were conducted on a hot, humid climate of Chennai (13°5′ 2" North, 80°16′ 12"East, India. The use of paraffin wax increases the latent heat storage so that the energy is stored in the PCM and in the absence of solar radiation it rejects its stored heat into the basin for further evaporation of water from the basin. Temperatures of water, Tw, Temperature of phase change material, TPCM, Temperature of cover, Tc were measured using thermocouple. Results show that there is an increase of maximum 20%, in productivity of fresh water with PCM. Keywords: fresh water production; PCM; thermal energy storage; phase change material

  9. Nanoscale Structure of Self-Assembling Hybrid Materials of Inorganic and Electronically Active Organic Phases

    Energy Technology Data Exchange (ETDEWEB)

    Sofos, M.; Goswami, D.A. Stone D.K.; Okasinski, J.S.; Jin, H.; Bedzyk, M.J.; Stupp, S.I. (NWU)

    2008-10-06

    Hybrid materials with nanoscale structure that incorporates inorganic and organic phases with electronic properties offer potential in an extensive functional space that includes photovoltaics, light emission, and sensing. This work describes the nanoscale structure of model hybrid materials with phases of silica and electronically active bola-amphiphile assemblies containing either oligo(p-phenylene vinylene) or oligo(thiophene) segments. The hybrid materials studied here were synthesized by evaporation-induced self-assembly and characterized by X-ray scattering techniques. Grazing-incidence X-ray scattering studies of these materials revealed the formation of two-dimensional hexagonally packed cylindrical micelles of the organic molecules with diameters between 3.1 and 3.6 nm and cylindrical axes parallel to the surface. During the self-assembly process at low pH, the cylindrical aggregates of conjugated molecules become surrounded by silica giving rise to a hybrid structure with long-range order. Specular X-ray reflectivity confirmed the long-range periodicity of the hybrid films within a specific range of molar ratios of tetraethyl orthosilicate to cationic amphiphile. We did not observe any long-range ordering in fully organic analogues unless quaternary ammonium groups were replaced by tertiary amines. These observations suggest that charge screening in these biscationic conjugated molecules by the mineral phase is a key factor in the evolution of long range order in the self-assembling hybrids.

  10. Direct observation of titanium-centered octahedra in titanium-antimony-tellurium phase-change material.

    Science.gov (United States)

    Rao, Feng; Song, Zhitang; Cheng, Yan; Liu, Xiaosong; Xia, Mengjiao; Li, Wei; Ding, Keyuan; Feng, Xuefei; Zhu, Min; Feng, Songlin

    2015-11-27

    Phase-change memory based on Ti0.4Sb2Te3 material has one order of magnitude faster Set speed and as low as one-fifth of the Reset energy compared with the conventional Ge2Sb2Te5 based device. However, the phase-transition mechanism of the Ti0.4Sb2Te3 material remains inconclusive due to the lack of direct experimental evidence. Here we report a direct atom-by-atom chemical identification of titanium-centered octahedra in crystalline Ti0.4Sb2Te3 material with a state-of-the-art atomic mapping technology. Further, by using soft X-ray absorption spectroscopy and density function theory simulations, we identify in amorphous Ti0.4Sb2Te3 the titanium atoms preferably maintain the octahedral configuration. Our work may pave the way to more thorough understanding and tailoring of the nature of the Ti-Sb-Te material, for promoting the development of dynamic random access memory-like phase-change memory as an emerging storage-class memory to reform current memory hierarchy.

  11. Experimental investigation of performances of microcapsule phase change material for thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Li, H. [Department of Material Science and Engineering, Nanjing University, Nanjing (China); Liu, X.; Wu, S. [Department of Physics, Nanjing University, Nanjing (China); Fang, G.

    2010-02-15

    Performances of microcapsule phase change material (MPCM) for thermal energy storage are investigated. The MPCM for thermal energy storage is prepared by a complex coacervation method with gelatin and acacia as wall materials and paraffin as core material in an emulsion system. A scanning electron microscope (SEM) was used to study the microstructure of the MPCM. In thermal analysis, a differential scanning calorimeter (DSC) was employed to determine the melting temperature, melting latent heat, solidification temperature, and solidification latent heat of the MPCM for thermal energy storage. The SEM micrograph indicates that the MPCM has been successfully synthesized and that the particle size of the MPCM is about 81 {mu}m. The DSC output results show that the melting temperature of the MPCM is 52.05 C, the melting latent heat is 141.03 kJ/kg, the solidification temperature is 59.68 C, and the solidification latent heat is 121.59 kJ/kg. The results prove that the MPCM for thermal energy storage has a larger phase change latent heat and suitable phase change temperature, so it can be considered as an efficient thermal energy storage material for heat utilizing systems. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  12. Effect of water-ice phase change on thermal performance of building materials

    Science.gov (United States)

    Kočí, Václav; Černý, Robert

    2016-07-01

    The effect of water ice-phase change on thermal performance of integrated building material is investigated in this paper. As a characteristic construction, simple external wall made of aerated autoclaved concrete was assumed which was exposed to dynamic climatic condition of Šerák, Czech Republic. The computational modelling of hygrothermal performance was carried out using computer codes HEMOT and SIFEL that work on the basis of finite element method. The effect of phase change was taken into account by fixed-domain method, when experimentally determined effective specific heat capacity was used as a material parameter. It comprises also the effect of heat consumption and heat release that accompany the water-ice phase change. Comparing to the results with specific heat capacity, the effect of phase change on thermal performance could be quantified. The results showed that temperature fields can differ more than 6 °C. Additionally, the amount energy transported through the wall may be higher up to 4 %. This confirmed, that the effect water-ice phase change should be included in all the relevant energy calculations.

  13. In Situ Environmental TEM in Imaging Gas and Liquid Phase Chemical Reactions for Materials Research.

    Science.gov (United States)

    Wu, Jianbo; Shan, Hao; Chen, Wenlong; Gu, Xin; Tao, Peng; Song, Chengyi; Shang, Wen; Deng, Tao

    2016-11-01

    Gas and liquid phase chemical reactions cover a broad range of research areas in materials science and engineering, including the synthesis of nanomaterials and application of nanomaterials, for example, in the areas of sensing, energy storage and conversion, catalysis, and bio-related applications. Environmental transmission electron microscopy (ETEM) provides a unique opportunity for monitoring gas and liquid phase reactions because it enables the observation of those reactions at the ultra-high spatial resolution, which is not achievable through other techniques. Here, the fundamental science and technology developments of gas and liquid phase TEM that facilitate the mechanistic study of the gas and liquid phase chemical reactions are discussed. Combined with other characterization tools integrated in TEM, unprecedented material behaviors and reaction mechanisms are observed through the use of the in situ gas and liquid phase TEM. These observations and also the recent applications in this emerging area are described. The current challenges in the imaging process are also discussed, including the imaging speed, imaging resolution, and data management.

  14. An ultra-fast optical shutter exploiting total light absorption in a phase change material

    Science.gov (United States)

    Jafari, Mohsen; Guo, L. Jay; Rais-Zadeh, Mina

    2017-02-01

    In this paper, we present an ultra-fast and high-contrast optical shutter with applications in atomic clock assemblies, integrated photonic systems, communication hardware, etc. The shutter design exploits the total light absorption phenomenon in a thin phase change (PC) material placed over a metal layer. The shutter switches between ON and OFF states by changing PC material phase and thus its refractive index. The PC material used in this work is Germanium Telluride (GeTe), a group IV-VI chalcogenide compound, which exhibits good optical contrast when switching from amorphous to crystalline state and vice versa. The stable phase changing behavior and reliability of GeTe and GeSbTe (GST) have been verified in optical memories and RF switches. Here, GeTe is used as it has a lower extinction coefficient in near-IR regions compared to GST. GeTe can be thermally transitioned between two phases by applying electrical pulses to an integrated heater. The memory behavior of GeTe results in zero static power consumption which is useful in applications requiring long time periods between switching activities. We previously demonstrated a meta-surface employing GeTe in sub-wavelength slits with >14 dB isolation at 1.5 μm by exciting the surface plasmon polariton and localized slit resonances. In this work, strong interference effects in a thin layer of GeTe over a gold mirror result in near total light absorption of up to 40 dB (21 dB measured) in the amorphous phase of the shutter at 780 nm with much less fabrication complexity. The optical loss at the shutter ON state is less than 1.5 dB. A nickel chrome (NiCr) heater provides the Joule heating energy required to achieve the crystallographic phase change. The measured switching speed is 2 μs.

  15. On the Inhibition of Linear Absorption in Opaque Materials Using Phase-Locked Harmonic Generation

    CERN Document Server

    Centini, Marco; Fazio, Eugenio; Pettazzi, Federico; Sibilia, Concita; Haus, Joseph W; Foreman, John V; Akozbek, Neset; Bloemer, Mark J; Scalora, Michael

    2008-01-01

    We theoretically predict and experimentally demonstrate inhibition of linear absorption for phase and group velocity mismatched second and third harmonic generation in strongly absorbing materials, GaAs in particular, at frequencies above the absorption edge. A 100-fs pump pulse tuned to 1300nm generates 650nm and 435nm second and third harmonic pulses that propagate across a 450 micron-thick GaAs substrate without being absorbed. We attribute this to a phase-locking mechanism that causes the pump to trap the harmonics and to impress them with its dispersive properties.

  16. Review of Development Survey of Phase Change Material Models in Building Applications

    Directory of Open Access Journals (Sweden)

    Hussein J. Akeiber

    2014-01-01

    Full Text Available The application of phase change materials (PCMs in green buildings has been increasing rapidly. PCM applications in green buildings include several development models. This paper briefly surveys the recent research and development activities of PCM technology in building applications. Firstly, a basic description of phase change and their principles is provided; the classification and applications of PCMs are also included. Secondly, PCM models in buildings are reviewed and discussed according to the wall, roof, floor, and cooling systems. Finally, conclusions are presented based on the collected data.

  17. From rice husk to high performance shape stabilized phase change materials for thermal energy storage

    DEFF Research Database (Denmark)

    Mehrali, Mohammad; Latibari, Sara Tahan; Rosen, Marc A.

    2016-01-01

    exceptional phase change behavior, having a desirable latent heat storage capacity of 175 kJ kg(-1). When exposed to high solar radiation intensities, the composites can absorb and store the thermal energy. An FTIR analysis of the SSPCMs indicated that there was no chemical interaction between the palmitic...... and excellent reversibility. The prepared SSPCMs with enhanced heat transfer and phase change properties provide a beneficial option for building energy conservation and solar energy applications owing to the low cost of raw materials and the simple synthetic technique....

  18. CarbAl Heat Transfer Material

    Science.gov (United States)

    Fink, Richard

    2015-01-01

    The increasing use of power electronics, such as high-current semiconductor devices and modules, within space vehicles is driving the need to develop specialty thermal management materials in both the packaging of these discrete devices and the packaging of modules consisting of these device arrays. Developed by Applied Nanotech, Inc. (ANI), CarbAl heat transfer material is uniquely characterized by its low density, high thermal diffusivity, and high thermal conductivity. Its coefficient of thermal expansion (CTE) is similar to most power electronic materials, making it an effective base plate substrate for state-of-the-art silicon carbide (SiC) super junction transistors. The material currently is being used to optimize hybrid vehicle inverter packaging. Adapting CarbAl-based substrates to space applications was a major focus of the SBIR project work. In Phase I, ANI completed modeling and experimentation to validate its deployment in a space environment. Key parameters related to cryogenic temperature scaling of CTE, thermal conductivity, and mechanical strength. In Phase II, the company concentrated on improving heat sinks and thermally conductive circuit boards for power electronic applications.

  19. Effects of Microencapsulated Phase Change Material (MPCM) on Critical Heat Flux in Pool Boiling

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung Dae; Kim, Seong Man; Kang, Sarah; Lee, Seung Won; Seo, Han; Bang, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2011-10-15

    Thermal power is limited by critical heat flux (CHF) in the nuclear power plant. And the in-vessel retention by external reactor vessel cooling (IVR-ERVC) is applied in some nuclear power plants; AP600, AP1000, Loviisa and APR1400. The heat removal capacity of IVR-ERVC is also restricted by CHF. So, it is essential to get CHF margin to improve an economics and a safety of the plant. There are some typical approaches to enhance CHF: vibrating the heater or fluid, coating with porous media on the heater surface, applying an electric field. The recent study related to the CHF is focus on using the nanofluid. In this paper, the new approach was investigated by using the microencapsulated phase change material (MPCM). MPCM is the particles whose diameter is from 0.1{mu}m to 1000{mu}m. The MPCM consists of the core material and the shell material. The core material can be solid, liquid, gas or even the mixture. The solid paraffin is the best candidate as the core material due to its stable chemical and thermal properties. And the shell material is generally synthesized polymer of about several micrometers in thickness. The most interesting feature of the MPCM is that the latent heat associated with the solid-liquid phase change is related to the heat transfer. When the MPCM is dispersed into the carrier fluid, a kind of suspension named as microencapsulated phase change slurry (MPCS) is formed. The study on the MPCS was conducted in field of both the heat transfer fluids and energy storage media. It is inspired by the fact that the latent heat can serve distribution to the additional CHF margin. The purpose of this work is to confirm whether or not the CHF is enhanced

  20. Structures, phase stabilities, and electrical potentials of Li-Si battery anode materials

    KAUST Repository

    Tipton, William W.

    2013-05-28

    The Li-Si materials system holds promise for use as an anode in Li-ion battery applications. For this system, we determine the charge capacity, voltage profiles, and energy storage density solely by ab initio methods without any experimental input. We determine the energetics of the stable and metastable Li-Si phases likely to form during the charging and discharging of a battery. Ab initio molecular dynamics simulations are used to model the structure of amorphous Li-Si as a function of composition, and a genetic algorithm coupled to density-functional theory searches the Li-Si binary phase diagram for small-cell, metastable crystal structures. Calculations of the phonon densities of states using density-functional perturbation theory for selected structures determine the importance of vibrational, including zero-point, contributions to the free energies. The energetics and local structural motifs of these metastable Li-Si phases closely resemble those of the amorphous phases, making these small unit cell crystal phases good approximants of the amorphous phase for use in further studies. The charge capacity is estimated, and the electrical potential profiles and the energy density of Li-Si anodes are predicted. We find, in good agreement with experimental measurements, that the formation of amorphous Li-Si only slightly increases the anode potential. Additionally, the genetic algorithm identifies a previously unreported member of the Li-Si binary phase diagram with composition Li5Si2 which is stable at 0 K with respect to previously known phases. We discuss its relationship to the partially occupied Li7Si3 phase. © 2013 American Physical Society.

  1. Wettability in the liquid Cu-Ag alloy – fireproof material – gas phase system

    Directory of Open Access Journals (Sweden)

    G. Siwiec

    2013-07-01

    Full Text Available In the present paper, results of wettability studies on the liquid metal – fireproof material – gas phase system using copper and Cu-Ag alloys as well as typical fireproof materials, i.e. aluminium oxide, magnesium oxide and graphite, are presented. Contact angle measurements were conducted at 1 373–1 573 K by means of a high-temperature microscope coupled with a camera and a computer equipped with a program for recording and analysing images. For the measurements, the sessile drop method was used.

  2. Molecular dynamics simulations of disordered materials from network glasses to phase-change memory alloys

    CERN Document Server

    Massobrio, Carlo; Bernasconi, Marco; Salmon, Philip S

    2015-01-01

    This book is a unique reference work in the area of atomic-scale simulation of glasses. For the first time, a highly selected panel of about 20 researchers provides, in a single book, their views, methodologies and applications on the use of molecular dynamics as a tool to describe glassy materials. The book covers a wide range of systems covering ""traditional"" network glasses, such as chalcogenides and oxides, as well as glasses for applications in the area of phase change materials. The novelty of this work is the interplay between molecular dynamics methods (both at the classical and firs

  3. IFMIF (International Fusion Materials Irradiation Facility) key element technology phase interim report

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Hiroo; Ida, Mizuho; Sugimoto, Masayoshi; Takeuchi, Hiroshi; Yutani, Toshiaki (eds.) [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2002-03-01

    Activities of International Fusion Materials Irradiation Facility (IFMIF) have been performed under an IEA collaboration since 1995. IFMIF is an accelerator-based deuteron (D{sup +})-lithium (Li) neutron source designed to produce an intense neutron field (2 MW/m{sup 2}, 20 dpa/year for Fe) in a volume of 500 cm{sup 3} for testing candidate fusion materials. In 2000, a 3 year Key Element technology Phase (KEP) of IFMIF was started to reduce the key technology risk factors. This interim report summarizes the KEP activities until mid 2001 in the major project work-breakdown areas of accelerator, target, test facilities and design integration. (author)

  4. Preparation and characterization of phase change material for thermal energy storage in buildings

    Science.gov (United States)

    Lo, Tommy Y.

    2016-04-01

    The paper presents the developing of novel form-stable composite phase change material (PCM) by incorporation of paraffin into lightweight aggregate through vacuum impregnation. The macro-encapsulated Paraffin-lightweight aggregate is a chemical compatible, thermal stable and thermal reliable PCM material for thermal energy storage applications in buildings. The 28 days compressive strength of NWAC using PCM-LWA is 33 - 53 MPa, which has an opportunity for structural purpose. Scanning electronic microscopic images indicated the paraffin can be held inside the porous structure of the aggregate. Thermal performance test showed that the cement paste panel with composite PCM can reduce the indoor temperature.

  5. Melting of Nanoprticle-Enhanced Phase Change Material inside Shell and Tube Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Seiyed Mohammad Javad Hosseini

    2013-01-01

    Full Text Available This paper presents a numerical study of melting of Nanoprticle-Enhanced phase change material (NEPCM inside a shell and tube heat exchanger using RT50 and copper particles as base material and nanoparticle, respectively. In this study, the effects of nanoparticles dispersion (, 0.03, and 0.05 on melting time, liquid fraction, and penetration length are investigated. The results show that the melting time decreases to 14.6% and the penetration length increases to 146% with increasing volume fraction of nanoparticle up to .

  6. Mathematical Modeling and Simulations of Phase Change Materials in Basic Orthogonal Coordinate Systems

    Energy Technology Data Exchange (ETDEWEB)

    Rousse, Daniel; Dutil, Yvan; Ben Salah, Nizar; Lassue, Stephane

    2010-09-15

    Energy storage components improve the energy efficiency of systems by reducing the mismatch between supply and demand. Phase change materials are attractive since they provide a high energy storage density at constant temperatures. Nevertheless, the incorporation of such materials in a particular application often calls for numerical analyses due to the non-linear nature of the problem. The review of the mathematical models will include selected results to enable one to start his/her research with an exhaustive overview of the subject. This overview also stresses the need to match experimental investigations with recent numerical analyses.

  7. Numerical study of heat transfer from a wall incorporating a phase change material

    Directory of Open Access Journals (Sweden)

    Bouttout A.

    2013-03-01

    Full Text Available A numerical study of the thermal behavior of walls made up of construction materials used in Algeria and walls containing a phase change materials is presented. The model, based on the enthalpy formulation, is described by an equation of heat transfer. This equation is solved by an implicit method of finite differences and algorithm of Thomas. We analyzed the influence of the wall’s thickness and its composition on the evolution during the time of the temperature of the inside face of thewall.

  8. Investigating Processes of Materials Formation via Liquid Phase and Cryogenic TEM

    Energy Technology Data Exchange (ETDEWEB)

    De Yoreo, James J.; Sommerdijk, Nico

    2016-06-14

    The formation of materials in solutions is a widespread phenomenon in synthetic, biological and geochemical systems, occurring through dynamic processes of nucleation, self-assembly, crystal growth, and coarsening. The recent advent of liquid phase TEM and advances in cryogenic TEM are transforming our understanding of these phenomena by providing new insights into the underlying physical and chemical mechanisms. The techniques have been applied to metallic and semiconductor nanoparticles, geochemical and biological minerals, electrochemical systems, macromolecular complexes, and selfassembling systems, both organic and inorganic. New instrumentation and methodologies currently on the horizon promise new opportunities for advancing the science of materials synthesis.

  9. Hardening in Two-Phase Materials. II. Plastic Strain and Mean Stress Hardening Rate

    DEFF Research Database (Denmark)

    Lilholt, Hans

    1977-01-01

    The strain parameters which are relevant in a tensile experiment, are analysed and related to the geometry of deformation and to the mean stress of two-phase materials. The hardening rate of the mean stress with respect to plastic strain is found to be useful in comparison between experiments and...... and theories, and it allows theories to be probed over a range of strains. Previous experiments on the fibre-reinforced material of copper-tungsten are analysed in relation to the geometry of deformation....

  10. Frequency and phase swept holograms in spectral hole-burning materials.

    Science.gov (United States)

    Bernet, S; Altner, S B; Graf, F R; Maniloff, E S; Renn, A; Wild, U P

    1995-08-01

    A new hologram type in spectral hole-burning systems is presented. During exposure, the frequency of narrow-band laser light is swept over a spectral range that corresponds to a few homogeneous linewidths of the spectrally selective recording material. Simultaneously the phase of the hologram is adjusted as a function of frequency-the phase sweep function. Because of the phase-reconstructing properties of holography, this recording technique programs the sample as a spectral amplitude and phase filter. We call this hologram type frequency and phase swept (FPS) holograms. Their properties and applications are summarized, and a straightforward theory is presented that describes all the diffraction phenomena observed to date. Thin FPS holograms show strongly asymmetric diffraction into conjugated diffraction orders, which is an unusual behavior for thin transmission holograms. Investigations demonstrate the advantages of FPS holograms with respect to conventional cw recording techniques in freq ncymultiplexed data storage. By choosing appropriate phase sweep functions, various features of holographic data storage can be optimized. Examples for cross-talk reduction, highest diffraction efficiency, and maximal readout stability are demonstrated. The properties of these FPS hologram types are deduced from theoretical considerations and confirmed by experiments.

  11. High Temperature Phase Change Materials for Thermal Energy Storage Applications: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, J.; Glatzmaier, G. C.; Starace, A.; Turchi, C.; Ortega, J.

    2011-08-01

    To store thermal energy, sensible and latent heat storage materials are widely used. Latent heat thermal energy storage (TES) systems using phase change materials (PCM) are useful because of their ability to charge and discharge a large amount of heat from a small mass at constant temperature during a phase transformation. Molten salt PCM candidates for cascaded PCMs were evaluated for the temperatures near 320 degrees C, 350 degrees C, and 380 degrees C. These temperatures were selected to fill the 300 degrees C to 400 degrees C operating range typical for parabolic trough systems, that is, as one might employ in three-PCM cascaded thermal storage. Based on the results, the best candidate for temperatures near 320 degrees C was the molten salt KNO3-4.5wt%KCl. For the 350 degrees C and 380 degrees C temperatures, the evaluated molten salts are not good candidates because of the corrosiveness and the high vapor pressure of the chlorides.

  12. Ultrafast broadband tuning of resonant optical nanostructures using phase change materials

    CERN Document Server

    Rudé, Miquel; Cetin, Arif E; Miller, Timothy A; Carrilero, Albert; Wall, Simon; de Abajo, F Javier García; Altug, Hatice; Pruneri, Valerio

    2015-01-01

    The phenomenon of extraordinary optical transmission {EOT} through arrays of nanoholes patterned in a metallic film has emerged as a promising tool for a wide range of applications, including photovoltaics, nonlinear optics, and sensing. Designs and methods enabling the dynamic tuning of the optical resonances of these structures are essential to build efficient optical devices, including modulators, switches, filters, and biosensors. However, the efficient combination of EOT and dynamic tuning remains a challenge, mainly because of the lack of materials that can induce modulation over a broad spectral range at high speeds. Here, we demonstrate tuneable resonance wavelength shifts as large as 385 nm - an order of magnitude higher than previously reported - through the combination of phase change materials {PCMs}, which exhibit dramatic variations in optical properties upon transitions between amorphous and crystalline phases, with properly designed subwavelength nanohole metallic arrays. We further find throu...

  13. Thermal Response Of An Aerated Concrete Wall With Micro-Encapsulated Phase Change Material

    Directory of Open Access Journals (Sweden)

    Halúzová Dušana

    2015-06-01

    Full Text Available For many years Phase Change Materials (PCM have attracted attention due to their ability to store large amounts of thermal energy. This property makes them a candidate for the use of passive heat storage. In many applications, they are used to avoid the overheating of the temperature of an indoor environment. This paper describes the behavior of phase change materials that are inbuilt in aerated concrete blocks. Two building samples of an aerated concrete wall were measured in laboratory equipment called “twin-boxes”. The first box consists of a traditional aerated concrete wall; the second one has additional PCM micro-encapsulated in the wall. The heat flux through the wall was measured and compared to simulation results modeled in the ESP-r program. This experimental measurement provides a foundation for a model that can be used to analyze further building constructions.

  14. Using multi-shell phase change materials layers for cooling a lithium-ion battery

    Directory of Open Access Journals (Sweden)

    Nasehi Ramin

    2016-01-01

    Full Text Available One of the cooling methods in engineering systems is usage of phase change materials. Phase change materials or PCMs, which have high latent heats, are usually used where high energy absorption in a constant temperature is required. This work presents a numerical analysis of PCMs effects on cooling Li-ion batteries and their decrease in temperature levels during intense discharge. In this study, three PCM shells with different thermo-physical specifications located around a battery pack is examined. The results of each possible arrangement are compared together and the best arrangement leading to the lowest battery temperature during discharge is identified. In addition, the recovery time for the system which is the time required for the PCMs to refreeze is investigated.

  15. Empirical Validation of a Thermal Model of a Complex Roof Including Phase Change Materials

    CERN Document Server

    Guichard, Stéphane; Bigot, Dimitri; Malet-Damour, Bruno; Libelle, Teddy; Boyer, Harry

    2015-01-01

    This paper deals with the empirical validation of a building thermal model using a phase change material (PCM) in a complex roof. A mathematical model dedicated to phase change materials based on the heat apparent capacity method was implemented in a multi-zone building simulation code, the aim being to increase understanding of the thermal behavior of the whole building with PCM technologies. To empirically validate the model, the methodology is based both on numerical and experimental studies. A parametric sensitivity analysis was performed and a set of parameters of the thermal model have been identified for optimization. The use of a generic optimization program called GenOpt coupled to the building simulation code enabled to determine the set of adequate parameters. We first present the empirical validation methodology and main results of previous work. We then give an overview of GenOpt and its coupling with the building simulation code. Finally, once the optimization results are obtained, comparisons o...

  16. Heat Transfer Modeling of Phase Change Materials in Multiple Plates Heat Exchanger

    Directory of Open Access Journals (Sweden)

    M. Alipanah

    2013-12-01

    Full Text Available Nowadays, given the increasing importance of energy sources, the possibility of energy storage in the heat exchangers through the Phase Change Materials (PCM and releasing it when needed have been extremely essential. This study seeks to model the domestic water heat system in which the paraffin is as the phase change material and it stores the solar energy. The behavior of a PCM plate was studied by writing the governing equations and solving them as the one-dimensional, implicit method and through numerical calculation of the method equations. Given the confirmed accuracy of performed modeling by the results of similar studies for the complete melting and solidification of PCM, the application of this system seems appropriate for the solar domestic water heaters.

  17. A Family of Reference Hugoniots for Two-phase Porous Materials

    Science.gov (United States)

    2015-06-01

    material, which are the adiabatic compression of the gaseous phase and the heat due to plastic work generated from the deformation of particles. The...heating mechanisms mentioned in the literature [7] are cracking, adiabatic shear banding, cumulative jetting, etc. In addition, the flow from the... compression and adiabatic expansion of condensed substances, [in Russian], Sarov, Russian Federal Nuclear Centre - VNIIEF, 2nd ed., 2006. 13. van Thiel M

  18. Water solar distiller productivity enhancement using concentrating solar water heater and phase change material (PCM)

    OpenAIRE

    Miqdam T. Chaichan; Hussein A. Kazem

    2015-01-01

    This paper investigates usage of thermal energy storage extracted from concentrating solar heater for water distillation. Paraffin wax selected as a suitable phase change material, and it was used for storing thermal energy in two different insulated treasurers. The paraffin wax is receiving hot water from concentrating solar dish. This solar energy stored in PCM as latent heat energy. Solar energy stored in a day time with a large quantity, and some heat retrieved for later use. Water’s temp...

  19. Field Testing of Low-Cost Bio-Based Phase Change Material

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Kaushik [ORNL; Childs, Phillip W [ORNL; Atchley, Jerald Allen [ORNL

    2013-03-01

    A test wall built with phase change material (PCM)-enhanced loose-fill cavity insulation was monitored for a period of about a year in the warm-humid climate of Charleston, South Carolina. The test wall was divided into various sections, one of which contained only loose-fill insulation and served as a control for comparing and evaluating the wall sections with the PCM-enhanced insulation. This report summarizes the findings of the field test.

  20. Computational Design and Analysis of Core Material of Single-Phase Capacitor Run Induction Motor

    Directory of Open Access Journals (Sweden)

    Gurmeet Singh

    2014-07-01

    Full Text Available A Single-phase induction motor (SPIM has very crucial role in industrial, domestic and commercial sectors. So, the efficient SPIM is a foremost requirement of today's market. For efficient motors, many research methodologies and propositions have been given by researchers in past. Various parameters like as stator/rotor slot variation, size and shape of stator/rotor slots, stator/rotor winding configuration, choice of core material etc. have momentous impact on machine design. Core material influences the motor performance to a degree. Magnetic flux linkage and leakage preliminary depends upon the magnetic properties of core material and air gap. The analysis of effects of core material on the magnetic flux distribution and the performance of induction motor is of immense importance to meet out the desirable performance. An increase in the air gap length will result in the air gap performance characteristics deterioration and decrease in air gap length will lead to serious mechanical balancing concern. So possibility of much variation in air gap beyond the limits on both sides is not feasible. For the optimized performance of the induction motor the core material plays a significant role. Using higher magnetic flux density, reduction on a magnetizing reactance and leakage of flux can be achieved. In this thesis work the analysis of single phase induction motor has been carried out with different core materials. The four models have been simulated using Ansys Maxwell 15.0. Higher flux density selection for same machine dimensions result into huge amount of reduction in iron core losses and thereby improve the efficiency. In this paper 2% higher efficiency has been achieved with Steel_1010 as compared to the machine using conventional D23 material. Out of four models result reflected by the machine using steel_1010 and steel_1008 are found to be better.

  1. Numerical Model and Analysis of Peak Temperature Reduction in LiFePO4 Battery Packs Using Phase Change Materials

    DEFF Research Database (Denmark)

    Coman, Paul Tiberiu; Veje, Christian

    2013-01-01

    Numerical model and analysis of peak temperature reduction in LiFePO4 battery packs using phase change materials......Numerical model and analysis of peak temperature reduction in LiFePO4 battery packs using phase change materials...

  2. Numerical Model and Analysis of Peak Temperature Reduction in LiFePO4 Battery Packs Using Phase Change Materials

    DEFF Research Database (Denmark)

    Coman, Paul Tiberiu; Veje, Christian

    2013-01-01

    Numerical model and analysis of peak temperature reduction in LiFePO4 battery packs using phase change materials......Numerical model and analysis of peak temperature reduction in LiFePO4 battery packs using phase change materials...

  3. Logic computation in phase change materials by threshold and memory switching.

    Science.gov (United States)

    Cassinerio, M; Ciocchini, N; Ielmini, D

    2013-11-06

    Memristors, namely hysteretic devices capable of changing their resistance in response to applied electrical stimuli, may provide new opportunities for future memory and computation, thanks to their scalable size, low switching energy and nonvolatile nature. We have developed a functionally complete set of logic functions including NOR, NAND and NOT gates, each utilizing a single phase-change memristor (PCM) where resistance switching is due to the phase transformation of an active chalcogenide material. The logic operations are enabled by the high functionality of nanoscale phase change, featuring voltage comparison, additive crystallization and pulse-induced amorphization. The nonvolatile nature of memristive states provides the basis for developing reconfigurable hybrid logic/memory circuits featuring low-power and high-speed switching. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Computation material science of structural-phase transformation in casting aluminium alloys

    Science.gov (United States)

    Golod, V. M.; Dobosh, L. Yu

    2017-04-01

    Successive stages of computer simulation the formation of the casting microstructure under non-equilibrium conditions of crystallization of multicomponent aluminum alloys are presented. On the basis of computer thermodynamics and heat transfer during solidification of macroscale shaped castings are specified the boundary conditions of local heat exchange at mesoscale modeling of non-equilibrium formation the solid phase and of the component redistribution between phases during coalescence of secondary dendrite branches. Computer analysis of structural - phase transitions based on the principle of additive physico-chemical effect of the alloy components in the process of diffusional - capillary morphological evolution of the dendrite structure and the o of local dendrite heterogeneity which stochastic nature and extent are revealed under metallographic study and modeling by the Monte Carlo method. The integrated computational materials science tools at researches of alloys are focused and implemented on analysis the multiple-factor system of casting processes and prediction of casting microstructure.

  5. THERMAL ENERGY STORAGE PROPERTIES OF FORMSTABLE PARAFFIN/RECYCLE BLOCK CONCRETE COMPOSITE PHASE CHANGE MATERIAL

    Directory of Open Access Journals (Sweden)

    PATTARAPORN SUTTAPHAKDEE

    2017-01-01

    Full Text Available In this research, the form-stable composite phase change material was developed by incorporating paraffin on recycle block concrete (RB through the vacuum impregnation method. The compatibility and thermal properties of RB impregnated with paraffin ranging from 0-35 wt% were characterized by Fourier transform infrared spectroscopy (FTIR and differential scanning calorimetry (DSC. Results revealed that paraffin was uniformly absorbed in RB with a good physical compatibility. The optimum adsorption ratio of paraffin in RB was 25 wt% which produced phase transition temperature of 52.85 OC and latent heat of 30.98 J/g. The obtained form-stable paraffin/RB composite PCM had proper latent heat and phase transition temperature and can be applied for thermal energy storage applications such as solar heating and cooling in buildings.

  6. Ultrafast terahertz-induced response of GeSbTe phase-change materials

    Energy Technology Data Exchange (ETDEWEB)

    Shu, Michael J. [Department of Applied Physics, Stanford University, Stanford, California 94305 (United States); Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Zalden, Peter [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Chen, Frank [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Weems, Ben [Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Chatzakis, Ioannis [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Xiong, Feng; Jeyasingh, Rakesh; Pop, Eric; Philip Wong, H.-S. [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Hoffmann, Matthias C. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Wuttig, Matthias [I. Physikalisches Institut, RWTH Aachen University, 52056 Aachen (Germany); JARA–Fundamentals of Information Technology, RWTH Aachen University, 52056 Aachen (Germany); Lindenberg, Aaron M., E-mail: aaronl@stanford.edu [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States)

    2014-06-23

    The time-resolved ultrafast electric field-driven response of crystalline and amorphous GeSbTe films has been measured all-optically, pumping with single-cycle terahertz pulses as a means of biasing phase-change materials on a sub-picosecond time-scale. Utilizing the near-band-gap transmission as a probe of the electronic and structural response below the switching threshold, we observe a field-induced heating of the carrier system and resolve the picosecond-time-scale energy relaxation processes and their dependence on the sample annealing condition in the crystalline phase. In the amorphous phase, an instantaneous electroabsorption response is observed, quadratic in the terahertz field, followed by field-driven lattice heating, with Ohmic behavior up to 200 kV/cm.

  7. Ultrafast terahertz-induced response of GeSbTe phase-change materials

    Science.gov (United States)

    Shu, Michael J.; Zalden, Peter; Chen, Frank; Weems, Ben; Chatzakis, Ioannis; Xiong, Feng; Jeyasingh, Rakesh; Hoffmann, Matthias C.; Pop, Eric; Philip Wong, H.-S.; Wuttig, Matthias; Lindenberg, Aaron M.

    2014-06-01

    The time-resolved ultrafast electric field-driven response of crystalline and amorphous GeSbTe films has been measured all-optically, pumping with single-cycle terahertz pulses as a means of biasing phase-change materials on a sub-picosecond time-scale. Utilizing the near-band-gap transmission as a probe of the electronic and structural response below the switching threshold, we observe a field-induced heating of the carrier system and resolve the picosecond-time-scale energy relaxation processes and their dependence on the sample annealing condition in the crystalline phase. In the amorphous phase, an instantaneous electroabsorption response is observed, quadratic in the terahertz field, followed by field-driven lattice heating, with Ohmic behavior up to 200 kV/cm.

  8. Ultrafast optical manipulation of atomic motion in multilayer Ge-Sb-Te phase change materials

    Directory of Open Access Journals (Sweden)

    Fons P.

    2013-03-01

    Full Text Available Phase change random access memory devices have evolved dramatically with the recent development of superlattice structure of Ge-Sb-Te material (GST-SL in terms of its low power consumption. The phase change in GST-SL is mainly characterized by the displacement of Ge atoms. Here we examine a new phase change method, that is the manipulation of Ge-Te bonds using linearly-polarized femtosecond near-infrared optical pulses. As a result, we found that the p-polarized pump pulse is more effective in inducing the reversible and irreversible displacement of Ge atoms along [111] direction in the local structure. This structural change would be induced by the anisotropic carrier-phonon interaction along the [111] direction created by the p-polarized pulse.

  9. Crystallisation, melting, recrystallisation and polymorphism of n-eicosane for application as a phase change material

    Energy Technology Data Exchange (ETDEWEB)

    Genovese, A. [School of Applied Science, RMIT University, G.P.O. Box 2476V, Melbourne, Vic. 3001 (Australia); Amarasinghe, G. [School of Applied Science, RMIT University, G.P.O. Box 2476V, Melbourne, Vic. 3001 (Australia); Glewis, M. [School of Applied Science, RMIT University, G.P.O. Box 2476V, Melbourne, Vic. 3001 (Australia); Mainwaring, D. [School of Applied Science, RMIT University, G.P.O. Box 2476V, Melbourne, Vic. 3001 (Australia); Shanks, Robert A. [School of Applied Science, RMIT University, G.P.O. Box 2476V, Melbourne, Vic. 3001 (Australia)]. E-mail: robert.shanks@rmit.edu.au

    2006-04-15

    Phase change materials (PCM) provide thermoregulation originating from the latent heat exchanged during melting or crystallisation. Linear hydrocarbons have weak interactions, but high symmetry, providing an effective quantity of latent heat over the most acceptable temperature range for applications. The ability to both melt and crystallise over a narrow range is made complex by nucleation, polymorphism and the kinetic nature of these changes. Differential scanning calorimetry (DSC), optical microscopy and temperature modulated DSC (TMDSC) was used to study the melting of n-eicosane. This PCM has a low deg.ree of supercooling and conversion to the most stable crystalline state (triclinic) that occurs rapidly from a metastable phase (rotator) state on cooling. TMDSC revealed a small, yet similar deg.ree of thermodynamic reversibility in the melting of each of the crystalline phases.

  10. Meso-Scale Modeling of Spall in a Heterogeneous Two-Phase Material

    Energy Technology Data Exchange (ETDEWEB)

    Springer, Harry Keo [Univ. of California, Davis, CA (United States)

    2008-07-11

    The influence of the heterogeneous second-phase particle structure and applied loading conditions on the ductile spall response of a model two-phase material was investigated. Quantitative metallography, three-dimensional (3D) meso-scale simulations (MSS), and small-scale spall experiments provided the foundation for this study. Nodular ductile iron (NDI) was selected as the model two-phase material for this study because it contains a large and readily identifiable second- phase particle population. Second-phase particles serve as the primary void nucleation sites in NDI and are, therefore, central to its ductile spall response. A mathematical model was developed for the NDI second-phase volume fraction that accounted for the non-uniform particle size and spacing distributions within the framework of a length-scale dependent Gaussian probability distribution function (PDF). This model was based on novel multiscale sampling measurements. A methodology was also developed for the computer generation of representative particle structures based on their mathematical description, enabling 3D MSS. MSS were used to investigate the effects of second-phase particle volume fraction and particle size, loading conditions, and physical domain size of simulation on the ductile spall response of a model two-phase material. MSS results reinforce existing model predictions, where the spall strength metric (SSM) logarithmically decreases with increasing particle volume fraction. While SSM predictions are nearly independent of applied load conditions at lower loading rates, which is consistent with previous studies, loading dependencies are observed at higher loading rates. There is also a logarithmic decrease in SSM for increasing (initial) void size, as well. A model was developed to account for the effects of loading rate, particle size, matrix sound-speed, and, in the NDI-specific case, the probabilistic particle volume fraction model. Small-scale spall experiments were designed

  11. Numerical analysis of phase change materials for thermal control of power battery of high power dissipations

    Science.gov (United States)

    Xia, X.; Zhang, H. Y.; Deng, Y. C.

    2016-08-01

    Solid-fluid phase change materials have been of increasing interest in various applications due to their high latent heat with minimum volume change. In this work, numerical analysis of phase change materials is carried out for the purpose of thermal control of the cylindrical power battery cells for applications in electric vehicles. Uniform heat density is applied at the battery cell, which is surrounded by phase change material (PCM) of paraffin wax type and contained in a metal housing. A two-dimensional geometry model is considered due to the model symmetry. The effects of power densities, heat transfer coefficients and onset melting temperatures are examined for the battery temperature evolution. Temperature plateaus can be observed from the present numerical analysis for the pure PCM cases, with the temperature level depending on the power densities, heat transfer coefficients, and melting temperatures. In addition, the copper foam of high thermal conductivity is inserted into the copper foam to enhance the heat transfer. In the modeling, the local thermal non-equilibrium between the metal foam and the PCM is taken into account and the temperatures for the metal foam and PCM are obtained respectively.

  12. Phase Change Material Trade Study: A Comparison Between Wax and Water for Manned Spacecraft

    Science.gov (United States)

    Quinn, Gregory; Hodgson, Ed; Stephan, Ryan A,

    2011-01-01

    Phase change material heat sinks have been recognized as an important tool in optimizing thermal control systems for space exploration vehicles and habitats that must deal with widely varying thermal loads and environments. In order to better focus technology investment in this arena, NASA has supported a trade study with the objective of identifying where the best potential pay-off can be found among identified aqueous and paraffin wax phase change materials and phase change material heat sink design approaches. The study used a representative exploration mission with well understood parameters to support the trade. Additional sensitivity studies were performed to ensure the applicability of study results across varying systems and destinations. Results from the study indicate that replacing a wax PCM heat sink with a water ice PCM heat sink has the potential to decrease the equivalent system mass of the mission s vehicle through a combination of a smaller heat sink and a slight 5% increase in radiator size or the addition of a lightweight heat pump. An evaluation of existing and emerging PCM heat sink technologies indicates that further mass savings should be achievable through continued development of those technologies. The largest mass savings may be realized by eliminating the melting and freezing pressure of wax and water, respectively.

  13. High-Temperature Phase Change Materials (PCM) Candidates for Thermal Energy Storage (TES) Applications

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, J. C.

    2011-09-01

    It is clearly understood that lower overall costs are a key factor to make renewable energy technologies competitive with traditional energy sources. Energy storage technology is one path to increase the value and reduce the cost of all renewable energy supplies. Concentrating solar power (CSP) technologies have the ability to dispatch electrical output to match peak demand periods by employing thermal energy storage (TES). Energy storage technologies require efficient materials with high energy density. Latent heat TES systems using phase change material (PCM) are useful because of their ability to charge and discharge a large amount of heat from a small mass at constant temperature during a phase transformation like melting-solidification. PCM technology relies on the energy absorption/liberation of the latent heat during a physical transformation. The main objective of this report is to provide an assessment of molten salts and metallic alloys proposed as candidate PCMs for TES applications, particularly in solar parabolic trough electrical power plants at a temperature range from 300..deg..C to 500..deg.. C. The physical properties most relevant for PCMs service were reviewed from the candidate selection list. Some of the PCM candidates were characterized for: chemical stability with some container materials; phase change transformation temperatures; and latent heats.

  14. A review on phase-change materials: Mathematical modeling and simulations

    Energy Technology Data Exchange (ETDEWEB)

    Dutil, Yvan; Rousse, Daniel R. [Chaire de Recherche Industrielle T3E, Ecole de technologie superieure, Universite du Quebec, 801 Boul. Mgr, Bourget Levis, QC G6V 9V6 (Canada); Salah, Nizar Ben [Laboratoire MMP, Ecole Superieure des Sciences et Techniques de Tunis, 5 Avenue Taha Hussein, BP 56, Bab Manara, Tunis (Tunisia); Lassue, Stephane; Zalewski, Laurent [LAMTI, Faculte des sciences appliquees, Universite d' Artois, Technoparc Futura, 62400 Bethune (France)

    2011-01-15

    Energy storage components improve the energy efficiency of systems by reducing the mismatch between supply and demand. For this purpose, phase-change materials are particularly attractive since they provide a high-energy storage density at a constant temperature which corresponds to the phase transition temperature of the material. Nevertheless, the incorporation of phase-change materials (PCMs) in a particular application calls for an analysis that will enable the researcher to optimize performances of systems. Due to the non-linear nature of the problem, numerical analysis is generally required to obtain appropriate solutions for the thermal behavior of systems. Therefore, a large amount of research has been carried out on PCMs behavior predictions. The review will present models based on the first law and on the second law of thermodynamics. It shows selected results for several configurations, from numerous authors so as to enable one to start his/her research with an exhaustive overview of the subject. This overview stresses the need to match experimental investigations with recent numerical analyses since in recent years, models mostly rely on other models in their validation stages. (author)

  15. The solidification of two-phase heterogeneous materials:Theory versus experiment

    Institute of Scientific and Technical Information of China (English)

    KIM; Tongbeum

    2009-01-01

    The solidification behavior of two-phase heterogeneous materials such as close-celled aluminum foams was analytically studied.The proposed analytical model can precisely predict the location of solidification front as well as the full solidification time for a two-phase heterogeneous material composed of aluminum melt and non-conducting air pores.Experiments using distilled water simulating the aluminum melt to be solidified(frozen)were subsequently conducted to validate the analytical model for two selected porosities(ε),ε=0 and 0.5.Full numerical simulations with the method of finite difference were also performed to examine the influence of pore shape on solidification.The remarkable agreement between theory and experiment suggests that the delay of solidification in the two-phase heterogeneous material is mainly caused by the reduction of bulk thermal conductivity due to the presence of pores,as this is the sole mechanism accounted for by the analytical model for solidification in a porous medium.

  16. Application of phase diagram calculations to development of new ultra-high temperature structural materials

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In-situ refractory metal intermetallic composites(RMICs) based either on (Nb, Si) or (Mo, Si, B) are candidate materials for ultra-high temperature applications (> 1 400 ℃). To provide a balance of mechanical and environmental properties, Nb-Si composites are typically alloyed with Ti and Cr, and Mo-Si-B composites are alloyed with Ti. Phase diagrams of Nb-Cr-Ti-Si and Mo-Si-B-Ti, as prerequisite knowledge for advanced materials design and processing development, are critically needed. The phase diagrams in the metal-rich regions of multicomponent Nb-Cr-Ti-Si and Mo-Si-B-Ti were rapidly established using the Calphad(Calculation of phase diagram) approach coupled with key experiments. The calculated isotherms, isopleths, and solidification paths were validated by experimental work. The important heterogeneous multiphase equilibria in both quaternary systems identified will offer engineers the opportunity to develop materials with a balance of properties for high-temperature applications.

  17. Contributions of the Department of Defense Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR) Programs to Training and Education: FY1999-FY2004

    Science.gov (United States)

    2006-01-01

    allows visual tracking, free-floating Magnetic Levitation ( Maglev ) haptic feedback with real surgical tools and sce- nario-based training that can be...Defense Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR) Programs to Training and Education: FY1999–FY2004 J.D...Department of Defense Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR) Programs to Training and Education: FY1999

  18. An Analysis of Information Systems Technology Initiatives and Small Businesses in the DoD Small Business Innovation Research (SBIR) Program

    Science.gov (United States)

    2012-09-01

    which aimed at analyzing and evaluating the SBIR program through a survey and case study methodology. The report contained 10 academic articles...highlights the difficulty in any academic research that might attempt to estimate the return on investment of federal funding used in the SBIR...military training tools, knowledge management tools (i.e., “InfoTracker,” which can detect text overlaps and identify plagiarism ), as well as

  19. Interference of the Bloch phase in layered materials with stacking shifts

    Science.gov (United States)

    Akashi, Ryosuke; Iida, Yo; Yamamoto, Kohei; Yoshizawa, Kanako

    2017-06-01

    In periodic systems, electronic wave functions of the eigenstates exhibit the periodically modulated Bloch phases and are characterized by their wave numbers k . We theoretically address the effects of the Bloch phase in general layered materials with a stacking shift. When the interlayer shift and the Bloch wave vector k satisfy certain conditions, interlayer transitions of electrons are prohibited by the interference of the Bloch phase. We specify the manifolds in the k space where the hybridization of the Bloch states between the layers is suppressed in accord with the stacking shift. These manifolds, named stacking-adapted interference manifolds (SAIM), are obviously applicable to general layered materials regardless of a detailed atomic configuration within the unit cell. We demonstrate the robustness and usefulness of the SAIM with first-principles calculations for layered boron nitride, transition-metal dichalcogenide, graphite, and black phosphorus. We also apply the SAIM to general three-dimensional crystals to derive special k-point paths for the respective Bravais lattices, along which the Bloch-phase interference strongly suppresses the band dispersion. Our theory provides a general view on the anisotropic electronic motion intrinsic to the periodic-lattice structure.

  20. Using phase information to enhance speckle noise reduction in the ultrasonic NDE of coarse grain materials

    Science.gov (United States)

    Lardner, Timothy; Li, Minghui; Gachagan, Anthony

    2014-02-01

    Materials with a coarse grain structure are becoming increasingly prevalent in industry due to their resilience to stress and corrosion. These materials are difficult to inspect with ultrasound because reflections from the grains lead to high noise levels which hinder the echoes of interest. Spatially Averaged Sub-Aperture Correlation Imaging (SASACI) is an advanced array beamforming technique that uses the cross-correlation between images from array sub-apertures to generate an image weighting matrix, in order to reduce noise levels. This paper presents a method inspired by SASACI to further improve imaging using phase information to refine focusing and reduce noise. A-scans from adjacent array elements are cross-correlated using both signal amplitude and phase to refine delay laws and minimize phase aberration. The phase-based and amplitude-based corrected images are used as inputs to a two-dimensional cross-correlation algorithm that will output a weighting matrix that can be applied to any conventional image. This approach was validated experimentally using a 5MHz array a coarse grained Inconel 625 step wedge, and compared to the Total Focusing Method (TFM). Initial results have seen SNR improvements of over 20dB compared to TFM, and a resolution that is much higher.

  1. An investigation on the effects of phase change material on material components used for high temperature thermal energy storage system

    Science.gov (United States)

    Kim, Taeil; Singh, Dileep; Zhao, Weihuan; Yua, Wenhua; France, David M.

    2016-05-01

    The latent heat thermal energy storage (LHTES) systems for concentrated solar power (CSP) plants with advanced power cycle require high temperature phase change materials (PCMs), Graphite foams with high thermal conductivity to enhance the poor thermal conductivity of PCMs. Brazing of the graphite foams to the structural metals of the LHTES system could be a method to assemble the system and a method to protect the structural metals from the molten salts. In the present study, the LHTES prototype capsules using MgCl2-graphite foam composites were assembled by brazing and welding, and tested to investigate the corrosion attack of the PCM salt on the BNi-4 braze. The microstructural analysis showed that the BNi-4 braze alloy can be used not only for the joining of structure alloy to graphite foams but also for the protecting of structure alloy from the corrosion by PCM.

  2. Modeling the viscoplastic micromechanical response of two-phase materials using fast Fourier transforms

    Energy Technology Data Exchange (ETDEWEB)

    Lebensohn, Ricardo A [Los Alamos National Laboratory; Lee, Sukbin [CMU; Rollett, Anthony D [CMU

    2009-01-01

    A viscoplastic approach using the Fast Fourier Transform (FFT) method for obtaining local mechanical response is utilized to study microstructure-property relationships in composite materials. Specifically, three-dimensional, two-phase digital materials containing isotropically coarsened particles surrounded by a matrix phase, generated through a Kinetic Monte Carlo Potts model for Ostwald ripening, are used as instantiations in order to calculate the stress and strain rate fields under uniaxial tension. The effects of the morphology of the matrix phase, the volume fraction and the contiguity of particles, and the polycrystallinity of matrix phase, on the stress and strain rate fields under uniaxial tension are examined. It is found that the first moments of the stress and strain rate fields have a different dependence on the particle volume fraction and the particle contiguity from their second moments. The average stresses and average strain rates of both phases and of the overall composite have rather simple relationships with the particle volume fraction whereas their standard deviations vary strongly, especially when the particle volume fraction is high, and the contiguity of particles has a noticeable effect on the mechanical response. It is also found that the shape of stress distribution in the BCC hard particle phase evolves as the volume fraction of particles in the composite varies, such that it agrees with the stress field in the BCC polycrystal as the volume of particles approaches unity. Finally, it is observed that the stress and strain rate fields in the microstructures with a polycrystalline matrix are less sensitive to changes in volume fraction and contiguity of particles.

  3. 美军SBIRS GEO-1预警卫星探测预警能力分析%Analysis on infrared detecting and early warning capabilities of America's SBIRS GEO-1 satellite

    Institute of Scientific and Technical Information of China (English)

    李小将; 金山; 廖海玲; 王建华

    2013-01-01

    For effectively responding to the threats of ballistic missiles and protecting the US's national and allies' interests, the US army continually develops and consummates the space-based infrared early warning system. The paper introduces the status and development of US's space-based infrared system,explores the coverage characteristic of the first space-based infrared geosynchronous orbit satellite,builds the GEO-1 satellite's infrared detecting model and early warning model, analyzes the detecting and early warning efficiencies of SBIRS GEO-1 satellite.%为有效应对弹道导弹威胁,维护本土与盟国利益,美军不断发展完善其天基红外预警系统.介绍了美军天基红外系统的发展现状,分析了首颗天基红外系统静止轨道(SBIRS GEO-1)卫星的覆盖范围,建立了SBIRS GEO-1卫星的红外探测模型和弹道预警模型,对其在轨探测预警能力进行了初步仿真分析.

  4. Novel solid – solid phase change material based on polyethylene glycol and cellulose used for temperature stabilisation

    Directory of Open Access Journals (Sweden)

    Wojda Marta

    2014-01-01

    Full Text Available Thermal management is one of crucial issues in the development of modern electronic devices. In the recent years interest in phase change materials (PCMs as alternative cooling possibility has increased significantly. Preliminary results concerning the research into possibility of the use of solid-solid phase change materials (S-S PCMs for stabilisation temperature of electronic devices has been presented in the paper. Novel solid-solid phase change material based on polyethylene glycol and cellulose has been synthesized. Attempt to improve its thermal conductivity has been taken. Material has been synthesized for the purpose of stabilisation of temperature of electronic devices.

  5. New methodology developed for the differential scanning calorimetry analysis of polymeric matrixes incorporating phase change materials

    Science.gov (United States)

    Barreneche, Camila; Solé, Aran; Miró, Laia; Martorell, Ingrid; Inés Fernández, A.; Cabeza, Luisa F.

    2012-08-01

    Nowadays, thermal comfort needs in buildings have led to an increase in energy consumption of the residential and service sectors. For this reason, thermal energy storage is shown as an alternative to achieve reduction of this high consumption. Phase change materials (PCM) have been studied to store energy due to their high storage capacity. A polymeric material capable of macroencapsulating PCM was developed by the authors of this paper. However, difficulties were found while measuring the thermal properties of these materials by differential scanning calorimetry (DSC). The polymeric matrix interferes in the detection of PCM properties by DSC. To remove this interfering effect, a new methodology which replaces the conventional empty crucible used as a reference in the DSC analysis by crucibles composed of the polymeric matrix was developed. Thus, a clear signal from the PCM is obtained by subtracting the new full crucible signal from the sample signal.

  6. A numerical study of latent thermal energy storage in a phase change material/carbon panel

    Science.gov (United States)

    Mekaddem, Najoua; Ali, Samia Ben; Mazioud, Atef; Hannachi, Ahmed

    2016-07-01

    To reduce the energetic dependence of building, it has become necessary to explore and develop new materials promoting energy conservation. Because of their high storage capacity, phase change materials (PCMs) are efficient to store thermal energy. In this paper, a 3D model was studied for simulation of energy storing cycles to predict the performances of PCM loaded panels. Carbon was used as supporting material for the PCM. The simulation was based on the enthalpy method using Ansys Fluent software. The panel was exposed to a daily heat flow including the effects of convection and radiation. The results show that the temperature decreased of approximately 2.5°C with a time shift about 2 hours. The steady state was reached after four cycles. Thus, after four cycles the PCM showed its effects on the temperature conditioning.

  7. A numerical study of latent thermal energy storage in a phase change material/carbon panel

    Energy Technology Data Exchange (ETDEWEB)

    Mekaddem, Najoua, E-mail: mekaddem.najoua@gmail.com; Ali, Samia Ben, E-mail: samia.benali@enig.rnu.tn; Hannachi, Ahmed, E-mail: ahmed.hannachi@enig.rnu.tn [Research Laboratory of Process Engineering and Industrial Systems, National Engineering School of Gabes (Tunisia); Mazioud, Atef, E-mail: mazioud@u-pec.fr [IUT Senart, Department of Industrial Engineering and Maintenance, University Paris-Est (France)

    2016-07-25

    To reduce the energetic dependence of building, it has become necessary to explore and develop new materials promoting energy conservation. Because of their high storage capacity, phase change materials (PCMs) are efficient to store thermal energy. In this paper, a 3D model was studied for simulation of energy storing cycles to predict the performances of PCM loaded panels. Carbon was used as supporting material for the PCM. The simulation was based on the enthalpy method using Ansys Fluent software. The panel was exposed to a daily heat flow including the effects of convection and radiation. The results show that the temperature decreased of approximately 2.5°C with a time shift about 2 hours. The steady state was reached after four cycles. Thus, after four cycles the PCM showed its effects on the temperature conditioning.

  8. A Route for Phase Control in Metal Nanoparticles: A Potential Strategy to Create Advanced Materials.

    Science.gov (United States)

    Kusada, Kohei; Kitagawa, Hiroshi

    2016-02-10

    There is untapped potential for materials whose crystal structures are unobtainable in the bulk state. Several examples of such structures have been found in nanomaterials, and these materials exhibit unique properties that arise from their unique electronic states and surface structures. Here, recent developments in the syntheses of these nanomaterials and their unique properties, such as hydrogen-storage ability and catalytic activity, are summarized. Firstly, the syntheses and properties of novel solid-solution alloy nanoparticles in immiscible alloy systems such as Ag-Rh and Pd-Ru are introduced. Following this, the crystal structure control of nanoscale Ru is discussed. These unique alloy materials show enhanced properties and highlight the potential of phase control to be a new strategy for nanomaterial development. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Fast Atomic-Scale Chemical Imaging of Crystalline Materials and Dynamic Phase Transformations.

    Science.gov (United States)

    Lu, Ping; Yuan, Ren Liang; Ihlefeld, Jon F; Spoerke, Erik David; Pan, Wei; Zuo, Jian Min

    2016-04-13

    Atomic-scale phenomena fundamentally influence materials form and function that makes the ability to locally probe and study these processes critical to advancing our understanding and development of materials. Atomic-scale chemical imaging by scanning transmission electron microscopy (STEM) using energy-dispersive X-ray spectroscopy (EDS) is a powerful approach to investigate solid crystal structures. Inefficient X-ray emission and collection, however, require long acquisition times (typically hundreds of seconds), making the technique incompatible with electron-beam sensitive materials and study of dynamic material phenomena. Here we describe an atomic-scale STEM-EDS chemical imaging technique that decreases the acquisition time to as little as one second, a reduction of more than 100 times. We demonstrate this new approach using LaAlO3 single crystal and study dynamic phase transformation in beam-sensitive Li[Li0.2Ni0.2Mn0.6]O2 (LNMO) lithium ion battery cathode material. By capturing a series of time-lapsed chemical maps, we show for the first time clear atomic-scale evidence of preferred Ni-mobility in LNMO transformation, revealing new kinetic mechanisms. These examples highlight the potential of this approach toward temporal, atomic-scale mapping of crystal structure and chemistry for investigating dynamic material phenomena.

  10. Time-resolved lattice measurements of shock-induced phase transitions in polycrystalline materials

    Science.gov (United States)

    Milathianaki, Despina

    The response of materials under extreme temperature and pressure conditions is a topic of great significance because of its relevance in astrophysics, geophysics, and inertial confinement fusion. In recent years, environments exceeding several hundred gigapascals in pressure have been produced in the laboratory via laser-based dynamic loading techniques. Shock-loading is of particular interest as the shock provides a fiducial for measuring time-dependent processes in the lattice such as phase transitions. Time-resolved x-ray diffraction is the only technique that offers an insight into these shock-induced processes at the relevant spatial (atomic) and temporal scales. In this study, nanosecond resolution x-ray diffraction techniques were developed and implemented towards the study of shock-induced phase transitions in polycrystalline materials. More specifically, the capability of a focusing x-ray diffraction geometry in high-resolution in situ lattice measurements was demonstrated by probing shock-compressed Cu and amorphous metallic glass samples. In addition, simultaneous lattice and free surface velocity measurements of shock-compressed Mg in the ambient hexagonal close packed (hcp) and shock-induced body centered cubic (bcc) phases between 12 and 45 GPa were performed. These measurements revealed x-ray diffraction signals consistent with a compressed bcc lattice above a shock pressure of 26.2+/-1.3 GPa, thus capturing for the first time direct lattice evidence of a shock-induced hcp to bcc phase transition in Mg. Our measurement of the hcp-bcc phase boundary in Mg was found to be consistent with the calculated boundary from generalized pseudopotential theory in the pressure and temperature region intersected by the principal shock Hugoniot. Furthermore, the subnanosecond timescale of the phase transition implied by the shock-loading conditions was in agreement with the kinetics of a martensitic transformation. In conclusion, we report on the progress and

  11. Small Business Innovation Research (SBIR) Program, FY 1992. Program Solicitation 92.1, Closing Date: 10 January 1992

    Science.gov (United States)

    1991-01-01

    identified by DoD designed in part, to provide incentives for the conversion Components. The guidelines presented in this solicitation of federally...system distributed operating system, and provide detailed specification guidelines and a model specification meeting Navy guidelines for a combat...SBIR Program Manager) (505) 844-4565 Bldg 523, Rm 305 Norton AFB CA 92409-6468 (Della Hinesley, 714-382-5371) AF92-100 thru 108 WL/ AAOP Terry Rogers

  12. Abstracts of Phase 1 awards, (fiscal year) 1987

    Energy Technology Data Exchange (ETDEWEB)

    1987-01-01

    Contained in this booklet are abstracts of the Phase I awards made in Fiscal Year 1987 under the Small Business Innovation Research (SBIR) program in the Department of Energy (DOE). The program is designed for implementation in a three-phase process, with Phase I determining the scientific or technical merit and feasibility of ideas proposed for investigation. The period of performance in this initial phase is relatively brief, typically about 6 months, and the awards are limited to $50,000. Phase II is the principal research or research and development effort, and the awards are as high as $500,000 for work to be performed in periods of up to 2 years. Phase III is the commercial application. The 111 Phase I projects described were selected in a highly competitive process from a total of 942 proposals received in response to the 1987 Solicitation. They cover the fields of chemistry, materials, control systems, plant natural products, instrumentation, nuclear medicine, health and environmental effects, high energy physics, particle accelerators, nuclear physics, plasma diagnostics and confinement, fusion energy systems, robotics and remote systems, nuclear reactors, space nuclear power, fuel cycle, decontamination/decommissioning, commputers in nuclear plants, coal, enhanced oil recovery/tar sands, fossil energy, photovoltaics, solar thermal, ceramics for heat engines, and industrial separation, conversion and recovery processes. (DLC)

  13. X-ray phase contrast imaging of the breast: Analysis of tissue simulating materials

    Energy Technology Data Exchange (ETDEWEB)

    Vedantham, Srinivasan; Karellas, Andrew [Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655 (United States)

    2013-04-15

    Purpose: Phase contrast imaging, particularly of the breast, is being actively investigated. The purpose of this work is to investigate the x-ray phase contrast properties of breast tissues and commonly used breast tissue substitutes or phantom materials with an aim of determining the phantom materials best representative of breast tissues. Methods: Elemental compositions of breast tissues including adipose, fibroglandular, and skin were used to determine the refractive index, n= 1 -{delta}+i {beta}. The real part of the refractive index, specifically the refractive index decrement ({delta}), over the energy range of 5-50 keV were determined using XOP software (version 2.3, European Synchrotron Radiation Facility, France). Calcium oxalate and calcium hydroxyapatite were considered to represent the material compositions of microcalcifications in vivo. Nineteen tissue substitutes were considered as possible candidates to represent adipose tissue, fibroglandular tissue and skin, and four phantom materials were considered as possible candidates to represent microcalcifications. For each material, either the molecular formula, if available, or the elemental composition based on weight fraction, was used to determine {delta}. At each x-ray photon energy, the absolute percent difference in {delta} between the breast tissue and the substitute material was determined, from which three candidates were selected. From these candidate tissue substitutes, the material that minimized the absolute percent difference in linear attenuation coefficient {mu}, and hence {beta}, was considered to be best representative of that breast tissue. Results: Over the energy range of 5-50 keV, while the {delta} of CB3 and fibroglandular tissue-equivalent material were within 1% of that of fibroglandular tissue, the {mu} of fibroglandular tissue-equivalent material better approximated the fibroglandular tissue. While the {delta} of BR10 and adipose tissue-equivalent material were within 1% of

  14. Influence of the pore size of reversed phase materials on peptide purification processes.

    Science.gov (United States)

    Gétaz, David; Dogan, Nihan; Forrer, Nicola; Morbidelli, Massimo

    2011-05-20

    The influence of the pore size of a chromatographic reversed phase material on the adsorption equilibria and diffusion of two industrially relevant peptides (i.e. a small synthetic peptide and insulin) has been studied using seven different reversed phase HPLC materials having pore sizes ranging from 90 Å to 300 Å. The stationary phase pore size distribution was obtained by inverse size exclusion measurement (iSEC). The effect of the pore size on the mass transfer properties of the materials was evaluated from Van Deemter experiments. It has been shown that the lumped mass transfer coefficient increases linearly with the average pore size. The Henry coefficient and the impurity selectivity were determined in diluted conditions. The saturation capacity of the main peptides was determined in overloaded conditions using the inverse method (i.e. peak fitting). It was shown that the adsorption equilibria of the peptides on the seven materials is well described by a surface-specific adsorption isotherm. Based on this a lumped kinetic model has been developed to model the elution profile of the two peptides in overloaded conditions and to simulate the purification of the peptide from its crude mixture. It has been found that the separation of insulin from its main impurity (i.e. desamido-insulin) was not affected by the pore size. On the other hand, in the case of the synthetic peptide, it was found that the adsorption of the most significant impurity decreases with the pore size. This decrease is probably due to an increase in silanol activity with decreasing pore size.

  15. Heat Transfer Characteristics of Liquid-Gas Taylor Flows incorporating Microencapsulated Phase Change Materials

    Science.gov (United States)

    Howard, J. A.; Walsh, P. A.

    2014-07-01

    This paper presents an investigation on the heat transfer characteristics associated with liquid-gas Taylor flows in mini channels incorporating microencapsulated phase change materials (MPCM). Taylor flows have been shown to result in heat transfer enhancements due to the fluid recirculation experienced within liquid slugs which is attributable to the alternating liquid slug and gas bubble flow structure. Microencapsulated phase change materials (MPCM) also offer significant potential with increased thermal capacity due to the latent heat required to cause phase change. The primary aim of this work was to examine the overall heat transfer potential associated with combining these two novel liquid cooling technologies. By investigating the local heat transfer characteristics, the augmentation/degradation over single phase liquid cooling was quantified while examining the effects of dimensionless variables, including Reynolds number, liquid slug length and gas void fraction. An experimental test facility was developed which had a heated test section and allowed MPCM-air Taylor flows to be subjected to a constant heat flux boundary condition. Infrared thermography was used to record high resolution experimental wall temperature measurements and determine local heat transfer coefficients from the thermal entrance point. 30.2% mass particle concentration of the MPCM suspension fluid was examined as it provided the maximum latent heat for absorption. Results demonstrate a significant reduction in experimental wall temperatures associated with MPCM-air Taylor flows when compared with the Graetz solution for conventional single phase coolants. Total enhancement in the thermally developed region is observed to be a combination of the individual contributions due to recirculation within the liquid slugs and also absorption of latent heat. Overall, the study highlights the potential heat transfer enhancements that are attainable within heat exchange devices employing MPCM

  16. Review of high-throughput techniques for detecting solid phase Transformation from material libraries produced by combinatorial methods

    Science.gov (United States)

    Lee, Jonathan A.

    2005-01-01

    High-throughput measurement techniques are reviewed for solid phase transformation from materials produced by combinatorial methods, which are highly efficient concepts to fabricate large variety of material libraries with different compositional gradients on a single wafer. Combinatorial methods hold high potential for reducing the time and costs associated with the development of new materials, as compared to time-consuming and labor-intensive conventional methods that test large batches of material, one- composition at a time. These high-throughput techniques can be automated to rapidly capture and analyze data, using the entire material library on a single wafer, thereby accelerating the pace of materials discovery and knowledge generation for solid phase transformations. The review covers experimental techniques that are applicable to inorganic materials such as shape memory alloys, graded materials, metal hydrides, ferric materials, semiconductors and industrial alloys.

  17. Small Business Innovation Research. Abstracts of Phase II awards, 2000

    Energy Technology Data Exchange (ETDEWEB)

    None

    2000-12-01

    The SBIR program enables DOE to obtain effective, innovative solutions to important problems through the private sector, which has a commercial incentive to pursue the resulting technology and bring it to the marketplace. The growing number of awardees, many of them started in business in response to SBIR solicitations, is becoming a significant resource for the solution of high risk, high technology problems for the Department. As detailed below, this publication describes the technical efforts and commercialization possibilities for SBIR Phase II awards in Fiscal Year (FY) 2000. It is intended for the educated layman, and maybe of particular interest to potential investors who wish to get in on the ground floor of exciting opportunities.

  18. High-Capacity, High-Voltage Composite Oxide Cathode Materials

    Science.gov (United States)

    Hagh, Nader M.

    2015-01-01

    This SBIR project integrates theoretical and experimental work to enable a new generation of high-capacity, high-voltage cathode materials that will lead to high-performance, robust energy storage systems. At low operating temperatures, commercially available electrode materials for lithium-ion (Li-ion) batteries do not meet energy and power requirements for NASA's planned exploration activities. NEI Corporation, in partnership with the University of California, San Diego, has developed layered composite cathode materials that increase power and energy densities at temperatures as low as 0 degC and considerably reduce the overall volume and weight of battery packs. In Phase I of the project, through innovations in the structure and morphology of composite electrode particles, the partners successfully demonstrated an energy density exceeding 1,000 Wh/kg at 4 V at room temperature. In Phase II, the team enhanced the kinetics of Li-ion transport and electronic conductivity at 0 degC. An important feature of the composite cathode is that it has at least two components that are structurally integrated. The layered material is electrochemically inactive; however, upon structural integration with a spinel material, the layered material can be electrochemically activated and deliver a large amount of energy with stable cycling.

  19. Thermal analysis on organic phase change materials for heat storage applications

    Science.gov (United States)

    Lager, Daniel

    2016-07-01

    In this paper, methodologies based on thermal analysis to evaluate specific heat capacity, phase transition enthalpies, thermal cycling stability and thermal conductivity of organic phase change materials (PCMs) are discussed. Calibration routines for a disc type heat flow differential scanning calorimetry (hf-DSC) are compared and the applied heating rates are adapted due to the low thermal conductivity of the organic PCMs. An assessment of thermal conductivity measurements based on "Laser Flash Analysis" (LFA) and the "Transient Hot Bridge" method (THB) in solid and liquid state has been performed. It could be shown that a disc type hf-DSC is a useful method for measuring specific heat capacity, melting enthalpies and cycling stability of organic PCM if temperature and sensitivity calibration are adapted to the material and quantity to be measured. The LFA method shows repeatable and reproducible thermal diffusivity results in solid state and a high effort for sample preparation in comparison to THB in liquid state. Thermal conductivity results of the two applied methods show large deviations in liquid phase and have to be validated by further experiments.

  20. Melting of a phase change material in a horizontal annulus with discrete heat sources

    Directory of Open Access Journals (Sweden)

    Mirzaei Hooshyar

    2015-01-01

    Full Text Available Phase change materials have found many industrial applications such as cooling of electronic devices and thermal energy storage. This paper investigates numerically the melting process of a phase change material in a two-dimensional horizontal annulus with different arrangements of two discrete heat sources. The sources are positioned on the inner cylinder of the annulus and assumed as constant-temperature boundary conditions. The remaining portion of the inner cylinder wall as well as the outer cylinder wall is considered to be insulated. The emphasis is mainly on the effects of the arrangement of the heat source pair on the fluid flow and heat transfer features. The governing equations are solved on a non-uniform O type mesh using a pressure-based finite volume method with an enthalpy porosity technique to trace the solid and liquid interface. The results are obtained at Ra=104 and presented in terms of streamlines, isotherms, melting phase front, liquid fraction and dimensionless heat flux. It is observed that, depending on the arrangement of heat sources, the liquid fraction increases both linearly and non-linearly with time but will slow down at the end of the melting process. It can also be concluded that proper arrangement of discrete heat sources has the great potential in improving the energy storage system. For instance, the arrangement C3 where the heat sources are located on the bottom part of the inner cylinder wall can expedite the melting process as compared to the other arrangements.

  1. CONTACT MATERIALS FOR GaSb AND InSb: A PHASE DIAGRAM APPROACH

    Institute of Scientific and Technical Information of China (English)

    K.W. Richter; H. Ipser

    2002-01-01

    The development of well defined and thermally stable ohmic contacts for Ⅲ- Ⅴ semi-conductors like InSb and GaSb is still a challenging problem in semiconductor devicetechnology. As device processing usually includes the exposure to elevated tempera-tures, interface reactions often occur during metallization and further heat treatment.It is thus important to understand the respective phase equilibria of the involved el-ements. From the thermodynamic point of view, binary and ternary compounds inequilibrium with the respective compound semiconductor would be the best choice forcontact materials as these contacts will be stable even after long exposure to elevatedtemperatures. These possible candidates for contact materials may be directly obtainedfrom the phase diagrams.During the last years we investigated several phase diagrams of transition metals withGaSb and InSb. Experimental results in the systems Ga-Ni-Sb, Ga-Pd-Sb, Ga-Pt-Sb,In-Ni-Sb and In-Pd-Sb are summarized and are discussed in the context of contactchemistry.

  2. Enhanced reversibility and unusual microstructure of a phase-transforming material.

    Science.gov (United States)

    Song, Yintao; Chen, Xian; Dabade, Vivekanand; Shield, Thomas W; James, Richard D

    2013-10-01

    Materials undergoing reversible solid-to-solid martensitic phase transformations are desirable for applications in medical sensors and actuators, eco-friendly refrigerators and energy conversion devices. The ability to pass back and forth through the phase transformation many times without degradation of properties (termed 'reversibility') is critical for these applications. Materials tuned to satisfy a certain geometric compatibility condition have been shown to exhibit high reversibility, measured by low hysteresis and small migration of transformation temperature under cycling. Recently, stronger compatibility conditions called the 'cofactor conditions' have been proposed theoretically to achieve even better reversibility. Here we report the enhanced reversibility and unusual microstructure of the first martensitic material, Zn45Au30Cu25, that closely satisfies the cofactor conditions. We observe four striking properties of this material. (1) Despite a transformation strain of 8%, the transformation temperature shifts less than 0.5 °C after more than 16,000 thermal cycles. For comparison, the transformation temperature of the ubiquitous NiTi alloy shifts up to 20 °C in the first 20 cycles. (2) The hysteresis remains approximately 2 °C during this cycling. For comparison, the hysteresis of the NiTi alloy is up to 70 °C (refs 9, 12). (3) The alloy exhibits an unusual riverine microstructure of martensite not seen in other martensites. (4) Unlike that of typical polycrystal martensites, its microstructure changes drastically in consecutive transformation cycles, whereas macroscopic properties such as transformation temperature and latent heat are nearly reproducible. These results promise a concrete strategy for seeking ultra-reliable martensitic materials.

  3. Phase Formation and Transformations in Transmutation Fuel Materials for the LIFE Engine Part I - Path Forward

    Energy Technology Data Exchange (ETDEWEB)

    Turchi, P E; Kaufman, L; Fluss, M J

    2008-11-10

    The current specifications of the LLNL fusion-fission hybrid proposal, namely LIFE, impose severe constraints on materials, and in particular on the nuclear fissile or fertile nuclear fuel and its immediate environment. This constitutes the focus of the present report with special emphasis on phase formation and phase transformations of the transmutation fuel and their consequences on particle and pebble thermal, chemical and mechanical integrities. We first review the work that has been done in recent years to improve materials properties under the Gen-IV project, and with in particular applications to HTGR and MSR, and also under GNEP and AFCI in the USA. Our goal is to assess the nuclear fuel options that currently exist together with their issues. Among the options, it is worth mentioning TRISO, IMF, and molten salts. The later option will not be discussed in details since an entire report is dedicated to it. Then, in a second part, with the specific LIFE specifications in mind, the various fuel options with their most critical issues are revisited with a path forward for each of them in terms of research, both experimental and theoretical. Since LIFE is applicable to very high burn-up of various fuels, distinctions will be made depending on the mission, i.e., energy production or incineration. Finally a few conclusions are drawn in terms of the specific needs for integrated materials modeling and the in depth knowledge on time-evolution thermochemistry that controls and drastically affects the performance of the nuclear materials and their immediate environment. Although LIFE demands materials that very likely have not yet been fully optimized, the challenge are not insurmountable and a well concerted experimental-modeling effort should lead to dramatic advances that should well serve other fission programs such as Gen-IV, GNEP, AFCI as well as the international fusion program, ITER.

  4. Potential industrial applications for composite phase-change materials as thermal energy storage media

    Energy Technology Data Exchange (ETDEWEB)

    Spanner, G.E.; Wilfert, G.L.

    1989-07-01

    Considerable effort has been spent by the US Department of Energy and its contractors over the last few years to develop composite phase-change materials (CPCMs) for thermal energy storage (TES). This patented TES medium consists of a phase-change material (typically a salt or metal alloy) that is retained within the porous structure of a supporting material (typically a ceramic). The objectives of this study were to (1) introduce CPCMs to industries that may not otherwise be aware of them, (2) identify potentially attractive applications for CPCM in industry, (3) determine technical requirements that will affect the design of CPCM's for specific applications, and (4) generate interest among industrial firms for employing CPCM TES in their processes. The approach in this study was to examine a wide variety of industries using a series of screens to select those industries that would be most likely to adopt CPCM TES in their processes. The screens used in this study were process temperature, presence of time-varying energy flows, energy intensity of the industry, and economic growth prospects over the next 5 years. After identifying industries that passed all of the screens, representatives of each industry were interviewed by telephone to introduce them to CPCM TES, assess technical requirements for CPCM TES in their industry, and determine their interest in pursuing applications for CPCM TES. 11 refs., 4 tabs.

  5. Multi-phase flow effect on SRM nozzle flow field and thermal protection materials

    Institute of Scientific and Technical Information of China (English)

    SHAFQAT Wahab; XIE Kan; LIU Yu

    2009-01-01

    Multi-phase flow effect generated from the combustion of aluminum based com-posite propellant was performed on the thermal protection material of solid rocket motor (SRM) nozzle. Injection of alumina (Al2O3) particles from 5% to 10% was tried on SRM nozzle flow field to see the influence of multiphase flow on heat transfer computations. A coupled, time resolved CFD (computational fluid dynamics) approach was adopted to solve the conjugate problem of multi-phase fluid flow and heat transfer in the solid rocket motor nozzle. The governing equations are discretized by using the finite volume method. Spalart-Allmaras (S-A) turbulence model was employed. The computation was executed on the dif-ferent models selected for the analysis to validate the temperature variation in the throat in-serts and baking material of SRM nozzle. Comparison for temperatures variations were also carried out at different expansion ratios of nozzle. This paper also characterized the advanced SRM nozzle composites material for their high thermo stability and their high thermo me-chanical capabilities to make it more reliable simpler and lighter.

  6. Experimental and Numerical Investigations of Thermal Ignition of a Phase Changing Energetic Material

    Directory of Open Access Journals (Sweden)

    Priyanka Shukla

    2016-04-01

    Full Text Available Fortuitous exposure to high temperatures initiates reaction in energetic materials and possibilities of such event are of great concern in terms of the safe and controlled usage of explosive devices. Experimental and numerical investigations on time to explosion and location of ignition of a phase changing polymer bonded explosive material (80 per cent RDX and 20 per cent binder, contained in a metallic confinement subjected to controlled temperature build-up on its surface, are presented. An experimental setup was developed in which the polymer bonded explosive material filled in a cylindrical confinement was provided with a precise control of surface heating rate. Temperature at various radial locations was monitored till ignition. A computational model for solving two dimensional unsteady heat transfer with phase change and heat generation due to multi-step chemical reaction was developed. This model was implemented using a custom field function in the framework of a finite volume method based standard commercial solver. Numerical study could simulate the transient heat conduction, the melting pattern of the explosive within the charge and also the thermal runaway. Computed values of temperature evolution at various radial locations and the time to ignition were closely agreeing with those measured in experiment. Results are helpful both in predicting the possibility of thermal ignition during accidents as well as for the design of safety systems.

  7. Geopolymer encapsulation of a chloride salt phase change material for high temperature thermal energy storage

    Science.gov (United States)

    Jacob, Rhys; Trout, Neil; Raud, Ralf; Clarke, Stephen; Steinberg, Theodore A.; Saman, Wasim; Bruno, Frank

    2016-05-01

    In an effort to reduce the cost and increase the material compatibility of encapsulated phase change materials (EPCMs) a new encapsulated system has been proposed. In the current study a molten salt eutectic of barium chloride (53% wt.), potassium chloride (28% wt.) and sodium chloride (19% wt.) has been identified as a promising candidate for low cost EPCM storage systems. The latent heat, melting point and thermal stability of the phase change material (PCM) was determined by DSC and was found to be in good agreement with results published in the literature. To cope with the corrosive nature of the PCM, it was decided that a fly-ash based geopolymer met the thermal and economic constraints for encapsulation. The thermal stability of the geopolymer shell was also tested with several formulations proving to form a stable shell for the chosen PCM at 200°C and/or 600°C. Lastly several capsules of the geopolymer shell with a chloride PCM were fabricated using a variety of methods with several samples remaining stable after exposure to 600°C testing.

  8. Crystal growth of an organic non-linear optical material from the vapour phase

    CERN Document Server

    Hou, W

    1999-01-01

    Due to the potential applications of organic non-linear optical materials in the areas of optical processing and communication, the investigation of the crystal growth of new organic NLO materials has been an active field for the last 20 years. For such uses it is necessary to produce single crystals of high quality and perfection, free of strain and defects. When crystals are grown from the solution and the melt, solvent and the decomposition component in the melt can introduce impurities and imperfection to the as-grown crystals. For crystals grown from vapour phase, in the absence of the solvent, this cannot occur and the method promises to yield single crystals of higher quality. Despite this attraction, little attention has been paid to the vapour phase growth of organic NLO crystals. It was with this in mind that the following investigation was carried out. Using Methyl p-hydroxybenzoate (p-MHB), a potential organic NLO material, a comparison investigation was made of its crystal growth from both the va...

  9. Structural Phase Transition and Material Properties of Few-Layer Monochalcogenides

    Science.gov (United States)

    Mehboudi, Mehrshad; Fregoso, Benjamin M.; Yang, Yurong; Zhu, Wenjuan; van der Zande, Arend; Ferrer, Jaime; Bellaiche, L.; Kumar, Pradeep; Barraza-Lopez, Salvador

    2016-12-01

    GeSe and SnSe monochalcogenide monolayers and bilayers undergo a two-dimensional phase transition from a rectangular unit cell to a square unit cell at a critical temperature Tc well below the melting point. Its consequences on material properties are studied within the framework of Car-Parrinello molecular dynamics and density-functional theory. No in-gap states develop as the structural transition takes place, so that these phase-change materials remain semiconducting below and above Tc. As the in-plane lattice transforms from a rectangle into a square at Tc, the electronic, spin, optical, and piezoelectric properties dramatically depart from earlier predictions. Indeed, the Y and X points in the Brillouin zone become effectively equivalent at Tc, leading to a symmetric electronic structure. The spin polarization at the conduction valley edge vanishes, and the hole conductivity must display an anomalous thermal increase at Tc. The linear optical absorption band edge must change its polarization as well, making this structural and electronic evolution verifiable by optical means. Much excitement is drawn by theoretical predictions of giant piezoelectricity and ferroelectricity in these materials, and we estimate a pyroelectric response of about 3 ×10-12 C /K m here. These results uncover the fundamental role of temperature as a control knob for the physical properties of few-layer group-IV monochalcogenides.

  10. Microencapsulation of phase change materials with carbon nanotubes reinforced shell for enhancement of thermal conductivity

    Science.gov (United States)

    Cui, Weiwei; Xia, Yongpeng; Zhang, Huanzhi; Xu, Fen; Zou, Yongjin; Xiang, Cuili; Chu, Hailiang; Qiu, Shujun; Sun, Lixian

    2017-03-01

    Novel microencapsulated phase change materials (micro-PCMs) were synthesized via in-situ polymerization with modified carbon nanotubes(CNTs) reinforced melamine-formaldehyde resin as shell material and CNTs reinforced n-octadecane as PCMs core. DSC results confirm that the micro-PCMs possess good phase change behavior and excellent thermal cycling stability. Melting enthalpy of the micro-PCMs can achieve 133.1 J/g and has slight changes after 20 times of thermal cyclings. And the incorporation of CNTs supplies the micro-PCMs with fast thermal response rate which increases the crystallization temperature of the micro-PCMs. Moreover, the thermal conductivity of the micro-PCMs has been significantly enhanced by introducing CNTs into their shell and core materials. And the thermal conductivity of micro-PCMs with 1.67 wt.% CNTs can increase by 25%. These results exhibit that the obtained micro-PCMs have a good prospect in thermal energy storage applications.

  11. High-field electrical transport in amorphous phase-change materials

    Science.gov (United States)

    Kaes, Matthias; Le Gallo, Manuel; Sebastian, Abu; Salinga, Martin; Krebs, Daniel

    2015-10-01

    Electrical transport in chalcogenide-based phase change materials is an active area of research owing to the prominent role played by these materials in the field of information technology. Here, we present transport measurements (IV curves) obtained on line-cells of as-deposited amorphous phase change materials (Ge2Sb2Te5, GeTe, Ag4In3Sb66Te27) over a wide voltage and temperature range (300 K to 160 K). The well defined geometry of our devices enables a description of the transport behavior in terms of conductivity vs. electric field. At higher temperatures (300 K ≥ T ≥ 220 K) and low to intermediate fields (F Poole-Frenkel emission from a two-center Coulomb potential. Based on this model, we observe a temperature dependence of the inter-trap distance, which we can relate to a temperature dependence in the occupation of the defect creating the Coulomb potential governing Poole-Frenkel emission. At higher fields and lower temperatures, the dependency of the IV curve on the electric field can be described by ln(I/I0) = (F/Fc)2. By combining this contribution with that of the Poole-Frenkel emission, we can show that the slope at high fields, Fc, is independent of temperature. We argue that models based on direct tunneling or thermally assisted tunneling from a single defect into the valence band cannot explain the observed behavior quantitatively.

  12. Effect of DMMP on the pyrolysis products of polyurethane foam materials in the gaseous phase

    Science.gov (United States)

    Liu, W.; Li, F.; Ge, X. G.; Zhang, Z. J.; He, J.; Gao, N.

    2016-07-01

    Dimethyl methylphosphonate (DMMP) has been used as a flame retardant containing phosphorus to decrease the flammability of the polyurethane foam material (PUF). Flame retardancy and thermal degradation of PUF samples have been investigated by the LOI tests and thermal analysis. The results show that LOI values of all PUF/DMMP samples are higher than that of the neat PUF sample and the LOI value of the samples increases with both DMMP concentration and the %P value. Thermal analysis indicates that flame retardant PUF shows a dominant condensed flame retardant activity during combustion. Thermogravimetric analysis-infrared spectrometry (TG-FTIR) has been used to study the influence of DMMP on the pyrolysis products in the gaseous phase during the thermal degradation of the PUF sample. Fourier transform infrared spectrometry (FTIR) spectra of the PUF sample at the maximum evolution rates and the generated trends of water and the products containing -NCO have been examined to obtain more information about the pyrolysis product evolutions of the samples at high temperature. These results reveal that although DMMP could improve the thermal stability of PUF samples through the formation of the residual char layer between fire and the decomposed materials, the influence of DMMP on the gaseous phase can be also observed during the thermal degradation process of materials.

  13. Ballistic missile locating and forecasting precision analysis based on the SBIRS-HIGH satellites%SBIRS-HIGH对导弹上升段位置测量精度及中末段位置预报精度的分析

    Institute of Scientific and Technical Information of China (English)

    范宏深; 贾祥瑞; 曾洪祥; 佛显超

    2006-01-01

    根据目前的技术水平分析了高空天基红外系统(SBIRS-HIGH)的技术参数;理论上计算了SBIRS-HIGH对导弹上升段的位置测量精度以及中末段任意时刻飞行位置的预报精度;研究了SBIRS-HIGH对中段和末端导弹拦截系统的导引能力.

  14. Phase and microstructural stability of electrolyte matrix materials for molten carbonate fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Choi, H.J.; Lee, J.J. [School of Advanced Materials Science and Engineering, College of Engineering, Yonsei University, Seoul 120-749 (Korea); Lim, H.C. [KEPRI, Korea Electric Power Research Institute, Yuseong-gu, Daejeon 103-16, 305-380 (Korea); Hyun, S.H.

    2010-08-15

    LiAlO{sub 2} powder is used as a material for molten-carbonate fuel cell (MCFC) matrices. The physical and chemical stabilities of LiAlO{sub 2} powder during MCFC operation determine the performance and lifetimes of the cells. Change to the phase and particle size in the allotropic phase of LiAlO{sub 2} was examined with long-term stability tests on pure {alpha}-LiAlO{sub 2} matrix, Al-reinforced {alpha}-LiAlO{sub 2} matrix, Al-reinforced {gamma}-LiAlO{sub 2} matrix, aqueous {gamma}-LiAlO{sub 2} matrix and an {alpha}-/{beta}-LiAlO{sub 2} mixture powder in molten carbonate at 650 C in air. In the {gamma}-LiAlO{sub 2} and {alpha}-/{beta}-LiAlO{sub 2} mixture, the particle growth was continuous from the early stages of heat-treatment to 20,000 h. Crystalline phase transformation ({gamma}-LiAlO{sub 2} and {beta}-LiAlO{sub 2} to {alpha}-LiAlO{sub 2} and {gamma}-LiAlO{sub 2}, respectively) of these powders and matrices also occurred, and {gamma}-LiAlO{sub 2} made the third phase like LiAl{sub 5}O{sub 8}. By contrast, the sizes of these particles and the crystalline phase of {alpha}-LiAlO{sub 2} did not change during immersion tests. These results show that, among {alpha}-/{beta}- and {gamma}-LiAlO{sub 2}, {alpha}-LiAlO{sub 2} is the most stable phase in molten carbonate. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  15. Review of the use of phase change materials (PCMs in buildings with reinforced concrete structures

    Directory of Open Access Journals (Sweden)

    Pons, O.

    2014-09-01

    Full Text Available Phase change materials are capable of storing and releasing energy in the form of heat in determined temperature ranges, so to increase a building’s thermal inertia, stabilize its indoor temperatures and reduce its energetic demand. Therefore, if we used these materials we could have more energetically efficient buildings. Nevertheless, are these materials most appropriate to be used in buildings? Could the incorporation of phase change materials in buildings with concrete structures be generalized? This article aims to carry out a review of these phase change materials from construction professionals’ points of view, study their applications for buildings with reinforced concrete structures and the key points for these applications, draw conclusions and provide recommendations useful for all professionals within the sector who are considering the application of these materials.Los materiales de cambio de fase son capaces de almacenar y liberar energía en forma de calor en un determinando rango de temperaturas, y así aumentar la inercia térmica de un edificio, estabilizar las temperaturas en el interior y reducir la demanda energética. En consecuencia, si utilizáramos estos materiales podríamos tener un parque de edificios más eficientes energéticamente. No obstante, ¿estos materiales son apropiados para usarse en edificios? ¿Se podría generalizar la incorporación de materiales de cambio de fase en edificios con estructuras de hormigón? Este artículo tiene como objetivos hacer una revisión del estado del arte de estos materiales de cambio de fase desde el punto de vista de los profesionales de la construcción, estudiar las aplicaciones en edificios con estructuras de hormigón armado y los puntos clave para estas aplicaciones, extraer conclusiones y recomendaciones útiles para los profesionales del sector que se planteen la utilización de estos materiales.

  16. A Preisach approach to modeling partial phase transitions in the first order magnetocaloric material MnFe(P,As)

    DEFF Research Database (Denmark)

    von Moos, Lars; Bahl, C.R.H.; Nielsen, Kaspar Kirstein;

    2014-01-01

    . Such materials are potential candidates for application in magnetic refrigeration devices. However, the first order materials often have adverse properties such as hysteresis, making actual performance troublesome to quantify, a subject not thoroughly studied within this field.Here we investigate the behavior...... of MnFe(P,As) under partial phase transitions, which is similar to what materials experience in actual magnetic refrigeration devices. Partial phase transition curves, in the absence of a magnetic field, are measured using calorimetry and the experimental results are compared to simulations......Magnetic refrigeration is an emerging technology that could provide energy efficient and environmentally friendly cooling. Magnetocaloric materials in which a structural phase transition is found concurrently with the magnetic phase transition are often termed first order magnetocaloric materials...

  17. Microstructure and electrical properties of Sb2Te phase-change material

    Science.gov (United States)

    Liu, Guangyu; Wu, Liangcai; Li, Tao; Rao, Feng; Song, Sannian; Liu, Bo; Song, Zhitang

    2016-10-01

    Phase Change Memory (PCM) has great potential for commercial applications of next generation non-volatile memory (NVM) due to its high operation speed, high endurance and low power consumption. Sb2Te (ST) is a common phase-change material and has fast crystallization speed, while thermal stability is relatively poor and its crystallization temperature is about 142°C. According to the Arrhenius law, the extrapolated failure temperature is about 55°C for ten years. When heated above the crystallization temperature while below the melting point, its structure can be transformed from amorphous phase to hexagonal phase. Due to the growth-dominated crystallization mechanism, the grain size of ST film is large and the diameter of about 300 nm is too large compared with Ge2Sb2Te5 (GST), which may deteriorate the device performance. High resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) were employed to study the microstructures and the results indicate that the crystal plane is {110}. In addition, device cells were manufactured and their current-voltage (I-V) and resistance-voltage characteristics were tested, and the results reveal that the threshold voltage (Vth) of ST film is 0.87 V. By researching the basic properties of ST, we can understand its disadvantages and manage to improve its performance by doping or other proper methods. Finally, the improved ST can be a candidate for optical discs and PCM.

  18. Preparation of CMC-modified melamine resin spherical nano-phase change energy storage materials.

    Science.gov (United States)

    Hu, Xiaofeng; Huang, Zhanhua; Zhang, Yanhua

    2014-01-30

    A novel carboxymethyl cellulose (CMC)-modified melamine-formaldehyde (MF) phase change capsule with excellent encapsulation was prepared by in situ polymerization. Effects of CMC on the properties of the capsules were studied by Fourier transformation infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electronic microscopy (SEM), X-ray diffractometry (XRD), and thermogravimetric analysis (TGA). The results showed that the CMC-modified capsules had an average diameter of about 50nm and good uniformity. The phase change enthalpy of the capsules was increased and the cracking ratio decreased by incorporating a suitable amount of CMC. The optimum phase change enthalpy of the nanocapsules was 83.46J/g, and their paraffin content was 63.1%. The heat resistance of the capsule shells decreased after CMC modification. In addition, the nanocapsule cracking ratio of the nanocapsules was 11.0%, which is highly attractive for their application as nano phase change materials. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Dental materials. Amorphous intergranular phases control the properties of rodent tooth enamel.

    Science.gov (United States)

    Gordon, Lyle M; Cohen, Michael J; MacRenaris, Keith W; Pasteris, Jill D; Seda, Takele; Joester, Derk

    2015-02-13

    Dental enamel, a hierarchical material composed primarily of hydroxylapatite nanowires, is susceptible to degradation by plaque biofilm-derived acids. The solubility of enamel strongly depends on the presence of Mg(2+), F(-), and CO3(2-). However, determining the distribution of these minor ions is challenging. We show—using atom probe tomography, x-ray absorption spectroscopy, and correlative techniques—that in unpigmented rodent enamel, Mg(2+) is predominantly present at grain boundaries as an intergranular phase of Mg-substituted amorphous calcium phosphate (Mg-ACP). In the pigmented enamel, a mixture of ferrihydrite and amorphous iron-calcium phosphate replaces the more soluble Mg-ACP, rendering it both harder and more resistant to acid attack. These results demonstrate the presence of enduring amorphous phases with a dramatic influence on the physical and chemical properties of the mature mineralized tissue.

  20. Experimental Research of Electronic Devices Thermal Control Using Metallic Phase Change Materials

    Institute of Scientific and Technical Information of China (English)

    Ai-Gang Pan; Jun-Biao Wang; Xian-Jie Zhang; Xiao-Bao Cao

    2014-01-01

    A Phase-change thermal control unit ( PTCU) filled with metallic phase change material ( PCM) Bismuth alloy for electric devices thermal protection was developed and investigated experimentally. The PTCU filled with PCM was designed and manufactured. Resistance heating components ( RCHs) produced 1 W, 3 W, 5 W, 7W, and 10 W for simulating heat generation of electronic devices. At various heating power levels, the performance of PTCU were tested during heating period and one duty cycle period. The experimental results show that the PTCU delays RCH reaching the maximum operating temperature. Also, a numerical model was developed to enable interpretation of experimental results and to perform parametric studies. The results confirmed that the PTCU is suitable for electric devices thermal control.

  1. Metal - Insulator Transition Driven by Vacancy Ordering in GeSbTe Phase Change Materials

    Science.gov (United States)

    Bragaglia, Valeria; Arciprete, Fabrizio; Zhang, Wei; Mio, Antonio Massimiliano; Zallo, Eugenio; Perumal, Karthick; Giussani, Alessandro; Cecchi, Stefano; Boschker, Jos Emiel; Riechert, Henning; Privitera, Stefania; Rimini, Emanuele; Mazzarello, Riccardo; Calarco, Raffaella

    2016-04-01

    Phase Change Materials (PCMs) are unique compounds employed in non-volatile random access memory thanks to the rapid and reversible transformation between the amorphous and crystalline state that display large differences in electrical and optical properties. In addition to the amorphous-to-crystalline transition, experimental results on polycrystalline GeSbTe alloys (GST) films evidenced a Metal-Insulator Transition (MIT) attributed to disorder in the crystalline phase. Here we report on a fundamental advance in the fabrication of GST with out-of-plane stacking of ordered vacancy layers by means of three distinct methods: Molecular Beam Epitaxy, thermal annealing and application of femtosecond laser pulses. We assess the degree of vacancy ordering and explicitly correlate it with the MIT. We further tune the ordering in a controlled fashion attaining a large range of resistivity. Employing ordered GST might allow the realization of cells with larger programming windows.

  2. Programming margin enlargement by material engineering for multilevel storage in phase-change memory

    Science.gov (United States)

    Yin, You; Noguchi, Tomoyuki; Ohno, Hiroki; Hosaka, Sumio

    2009-09-01

    In this work, we investigate the effect of the material engineering on programming margin in the double-layered phase-change memory, which is the most important parameter for the stability of multilevel storage. Compared with the TiN/SbTeN cell, the TiSiN/GeSbTe double-layered cell exhibits the resistance ratio of the highest to lowest resistance levels up to two to three orders of magnitude, indicating much larger programming margin and thus higher stability and/or more available levels. Our calculation results show that the resistivities of the top heating layer and the phase-change layer have a significant effect on the programming margin.

  3. Gas-driven subharmonic waves in a vibrated two-phase granular material.

    Science.gov (United States)

    Matas, J-P; Uehara, J; Behringer, R P

    2008-04-01

    Vibrated powders exhibit striking phenomena: subharmonic waves, oscillons, convection, heaping, and even bubbling. We demonstrate novel rectangular profile subharmonic waves for vibrated granular material, that occur uniquely in the two-phase case of grains, and a fluid, such as air. These waves differ substantially from those for the gas-free case, exhibit different dispersion relations, and occur for specific shaking parameters and air pressure, understandable with gas-particle flow models. These waves occur when the gas diffusively penetrates the granular layer in a time comparable to the shaker period. As the pressure is lowered towards P =0, the granular-gas system exhibits a Knudsen regime. This instability provides an opportunity to quantitatively test models of two-phase flow.

  4. Mapping of the photo-induced metastable and hidden phases in 2D electronic materials

    Science.gov (United States)

    Zhou, Faran; Sun, Tianyin; Han, Tzong-Ru; Malliakas, Christos; Duxbury, Phillip; Mahanti, Subhendra; Kanatzidis, Mercouri; Ruan, Chong-Yu; MSU Team; NU Team

    Using the ultrafast electron imaging techniques, we studied the light-induced phase transitions in transition-metal dichalcogenide materials. A succession of different phases was introduced transiently using femtosecond mid-infrared pulses and the local atomic scale charge-density-wave dynamics and morphological evolution of the long-range textured domains were in situ characterized using the ultrashort coherent electron pulses. The various metastable and hidden states emerging under the controlled nonthermal, nonadiabatic driving highlight the interaction-driven nature of these transitions with limited involvement of lattice entropy. The methodology introduced here can be generally applied to survey the complex energy landscape in strongly correlated electron systems, avoiding the difficulty of electrostatic gating or confounding effects due to defects and/or disorder. In particular, the observation of robust non-thermal switching at meso-scales and at ultrafast timescales, provides a platform for designing high-speed low-energy consumption nano-photonics and electronics devices.

  5. Testing of the functional garments with microencapsulated phase-change material in simulated high temperature conditions

    Directory of Open Access Journals (Sweden)

    Jovanović Dalibor B.

    2016-01-01

    Full Text Available An organic Phase Change Material (PCM possesses the ability to absorb and release large quantity of latent heat during a phase change process over a certain temperature range. This paper presents results related to thermo-physiological efficiency of special underwear with organic PCM integrated in textile through microencapsulation process. The efficiency of PCM underwear was tested through physiological examinations in simulated high-temperature conditions, where test-subjects were voluntarily exposed to heat stress tests wearing NBC protective suit with PCM underwear (option "THERM" and without it (option "NoTHERM". It can be concluded that wearing a PCM textile clothes under NBC protective suit, during physical activity in high-tempearture conditions, reduces sweating and alleviates heat stress manifested by increased core and skin temperature and heart rate values. [Projekat Ministarstva nauke Republike Srbije, br. TR34034

  6. Small Business Innovation Research GRC Phase I, Phase II, and Post-Phase II Opportunity Assessment for 2015

    Science.gov (United States)

    Nguyen, Hung D.; Steele, Gynelle C.

    2016-01-01

    This report outlines the 2015 Small Business Innovation Research/Small Business Technology Transfer (SBIR/STTR) Phase I, Phase II, and Post-Phase II opportunity contract award results associated with NASA's Aeronautics Research Mission Directorate (ARMD), Human Exploration and Operations Mission Directorate (HEOMD), Science Mission Directorate (SMD), and Space Technology Mission Directorate (STMD) for NASA Glenn Research Center. The report also highlights the number of Phase I, Phase II, and Post-Phase II contracts awarded by mission directorate. The 2015 Phase I contract awards to companies in Ohio and their corresponding technologies are also discussed.

  7. Formation dynamics of femtosecond laser-induced phase objects in transparent materials

    Science.gov (United States)

    Mermillod-Blondin, A.; Rosenfeld, A.; Stoian, R.; Audouard, E.

    2012-01-01

    Ultrashort pulse lasers offer the possibility to structure the bulk of transparent materials on a microscale. As a result, the optical properties of the irradiated material are locally modified in a permanent fashion. Depending on the irradiation parameters, different types of laser-induced phase objects can be expected, from uniform voxels (that can exhibit higher or lower refractive index than the bulk) to self-organized nanoplanes. We study the physical mechanisms that lead to material restructuring, with a particular emphasis on events taking place on a sub picosecond to a microsecond timescale following laser excitation. Those timescales are particularly interesting as they correspond to the temporal distances between two consecutive laser pulses when performing multiple pulse irradiation: burst microprocessing usually involves picosecond separation times and high repetition rate systems operate in the MHz range. We employ a time-resolved microscopy technique based on a phase-contrast microscope setup extended into a pump-probe scheme. This methods enables a dynamic observation of the complex refractive index in the interaction region with a time resolution better than 300 fs. In optical transmission mode, the transient absorption coefficient can be measured for different illumination wavelengths (400 nm and 800 nm). The phase-contrast mode provides qualitative information about the real part of the transient refractive index. Based on the study of those transient optical properties, we observe the onset and relaxation of the laser-generated plasma into different channels such as defect creation, sample heating, and shockwave generation. The majority of our experiments were carried out with amorphous silica, but our method can be applied to the study of all transparent media.

  8. Ferromagnetism modulation by phase change in Mn-doped GeTe chalcogenide magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Adam, Adam Abdalla Elbashir [Huazhong University of Science and Technology, School of Optical and Electronic Information, Wuhan (China); Wuhan National Laboratory for Optoelectronics, Wuhan (China); Alneelain University, Faculty of Science and Technology, Khartoum (Sudan); Cheng, Xiaomin; Guan, Xiawei; Miao, Xiangshui [Huazhong University of Science and Technology, School of Optical and Electronic Information, Wuhan (China); Wuhan National Laboratory for Optoelectronics, Wuhan (China)

    2014-12-15

    In this work, an effective method to modulate the ferromagnetic properties of Mn-doped GeTe chalcogenide-based phase change materials is presented. The microstructure of the phase change magnetic material Ge{sub 1-x} Mn{sub x} Te thin films was studied. The X-ray diffraction results demonstrate that the as-deposited films are amorphous, and the crystalline films are formed after annealing at 350 C for 10 min. Crystallographic structure investigation shows the existence of some secondary magnetic phases. The lattice parameters of Ge{sub 1-x} Mn{sub x} Te (x = 0.04, 0.12 and 0.15) thin films are found to be slightly different with changes of Mn compositions. The structural analysis clearly indicates that all the films have a stable rhombohedral face-centered cubic polycrystalline structure. The magnetic properties of the amorphous and crystalline Ge{sub 0.96}Mn{sub 0.04}Te were investigated. The measurements of magnetization (M) as a function of the magnetic field (H) show that both amorphous and crystalline phases of Ge{sub 0.96}Mn{sub 0.04}Te thin film are ferromagnetic and there is drastic variation between amorphous and crystalline states. The temperature (T) dependence of magnetizations at zero field cooling (ZFC) and field cooling (FC) conditions of the crystalline Ge{sub 0.96}Mn{sub 0.04}Te thin film under different applied magnetic fields were performed. The measured data at 100 and 300 Oe applied magnetic fields show large bifurcations in the ZFC and FC curves while on the 5,000 Oe magnetic field there is no deviation. (orig.)

  9. First-principles computation of mantle materials in crystalline and amorphous phases

    Science.gov (United States)

    Karki, Bijaya B.

    2015-03-01

    First-principles methods based on density functional theory are used extensively in the investigation of the behavior and properties of mantle materials over broad ranges of pressure, temperature, and composition that are relevant. A review of computational results reported during the last couple of decades shows that essentially all properties including structure, phase transition, equation of state, thermodynamics, elasticity, alloying, conductivity, defects, interfaces, diffusivity, viscosity, and melting have been calculated from first principles. Using MgO, the second most abundant oxide of Earth's mantle, as a primary example and considering many other mantle materials in their crystalline and amorphous phases, we have found that most properties are strongly pressure dependent, sometimes varying non-monotonically and anomalously, with the effects of temperature being systematically suppressed with compression. The overall agreement with the available experimental data is excellent; it is remarkable that the early-calculated results such as shear wave velocities of two key phases, MgO and MgSiO3 perovskite, were subsequently reproduced by experimentation covering almost the entire mantle pressure regime. As covered in some detail, the defect formation and migration enthalpies of key mantle materials increase with pressure. The predicted trend is that partial MgO Schottky defects are energetically most favorable in Mg-silicates but their formation enthalpies are high. So, the diffusion in the mantle is likely to be in the extrinsic regime. Preliminary results on MgO and forsterite hint that the grain boundaries can accommodate point defects (including impurities) and enhance diffusion rates at all pressures. The structures are highly distorted in the close vicinity of the defects and at the interface with excess space. Recent simulations of MgO-SiO2 binary and other silicate melts have found that the melt self-diffusion and viscosity vary by several orders of

  10. Numerical computation of solar heat storage in phase change material/concrete wall

    Directory of Open Access Journals (Sweden)

    Mustapha Faraji

    2014-01-01

    Full Text Available A one-dimensional mathematical model was developed in order to analyze and optimize the latent heat storage wall. Two layers of phase change material (PCM are sandwiched within a concrete wall. The governing equations for energy transport were developed by using the enthalpy method and discretized with volume control scheme. A series of numerical investigations were conducted. The effect of the melting temperature on the possibility of increasing the energy performance of the proposed heating system was analyzed. Results are obtained for thermal gain and temperature fluctuation. The charging/discharging process was also presented and analyzed.

  11. Analysis of Phase Change Material in Glazing Systems in Future Zero-Energy-Buildings

    DEFF Research Database (Denmark)

    Winther, Frederik Vildbrad; Heiselberg, Per; Jensen, Rasmus Lund

    2016-01-01

    the thermal storage capacity of the glazed facade by using phase change material (PCM), in the glazing cavity, reduces the cooling demand. When wanting to use this technology under colder weather conditions, the pane can potentially reduce the heat loss of the pane thereby minimizing energy demand for heating.......When designing glazed constructions, this often results in thermally light constructions, with a low time constant. In order for these buildings to improve the redistribution of loads between night and day, solutions such as active slabs and exposed concrete cores are often used. However...

  12. Melting of nanoparticles-enhanced phase change material (NEPCM) in vertical semicircle enclosure: numerical study

    Energy Technology Data Exchange (ETDEWEB)

    Jourabian, Mahmoud [University of Trieste, Piazzale (Italy); Farhadi, Mousa [Babol Noshirvani University of Technology, Shariati Avenue (Iran, Islamic Republic of)

    2015-09-15

    Convection melting of ice as a Phase change material (PCM) dispersed with Cu nanoparticles, which is encapsulated in a semicircle enclosure is studied numerically. The enthalpy-based Lattice Boltzmann method (LBM) combined with a Double distribution function (DDF) model is used to solve the convection-diffusion equation. The increase in solid concentration of nanoparticles results in the enhancement of thermal conductivity of PCM and the decrease in the latent heat of fusion. By enhancing solid concentration of nanoparticles, the viscosity of nanofluid increases and convective heat transfer dwindles. For all Rayleigh numbers investigated in this study, the insertion of nanoparticles in PCM has no effect on the average Nusselt number.

  13. Re-utilization of Industrial CO2 for Algae Production Using a Phase Change Material

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, Brian

    2013-12-31

    This is the final report of a 36-month Phase II cooperative agreement. Under this project, Touchstone Research Laboratory (Touchstone) investigated the merits of incorporating a Phase Change Material (PCM) into an open-pond algae production system that can capture and re-use the CO2 from a coal-fired flue gas source located in Wooster, OH. The primary objective of the project was to design, construct, and operate a series of open algae ponds that accept a slipstream of flue gas from a coal-fired source and convert a significant portion of the CO2 to liquid biofuels, electricity, and specialty products, while demonstrating the merits of the PCM technology. Construction of the pilot facility and shakedown of the facility in Wooster, OH, was completed during the first two years, and the focus of the last year was on operations and the cultivation of algae. During this Phase II effort a large-scale algae concentration unit from OpenAlgae was installed and utilized to continuously harvest algae from indoor raceways. An Algae Lysing Unit and Oil Recovery Unit were also received and installed. Initial parameters for lysing nanochloropsis were tested. Conditions were established that showed the lysing operation was effective at killing the algae cells. Continuous harvesting activities yielded over 200 kg algae dry weight for Ponds 1, 2 and 4. Studies were conducted to determine the effect of anaerobic digestion effluent as a nutrient source and the resulting lipid productivity of the algae. Lipid content and total fatty acids were unaffected by culture system and nutrient source, indicating that open raceway ponds fed diluted anaerobic digestion effluent can obtain similar lipid productivities to open raceway ponds using commercial nutrients. Data were also collected with respect to the performance of the PCM material on the pilot-scale raceway ponds. Parameters such as evaporative water loss, temperature differences, and growth/productivity were tracked. The pond with the

  14. Simultaneous microscopic measurements of thermal and spectroscopic fields of a phase change material

    Science.gov (United States)

    Romano, M.; Ryu, M.; Morikawa, J.; Batsale, J. C.; Pradere, C.

    2016-05-01

    In this paper, simultaneous microscopic measurements of thermal and spectroscopic fields of a paraffin wax n-alkane phase change material are reported. Measurements collected using an original set-up are presented and discussed with emphasis on the ability to perform simultaneous characterization of the system when the proposed imaging process is used. Finally, this work reveals that the infrared wavelength contains two sets of important information. Furthermore, this versatile and flexible technique is well adapted to characterize many systems in which the mass and heat transfers effects are coupled.

  15. Random-phase approximation and its applications in computational chemistry and materials science

    Science.gov (United States)

    Ren, Xinguo; Rinke, Patrick; Joas, Christian; Scheffler, Matthias

    2012-11-01

    The random-phase approximation (RPA) as an approach for computing the electronic correlation energy is reviewed. After a brief account of its basic concept and historical development, the paper is devoted to the theoretical formulations of RPA, and its applications to realistic systems. With several illustrating applications, we discuss the implications of RPA for computational chemistry and materials science. The computational cost of RPA is also addressed which is critical for its widespread use in future applications. In addition, current correction schemes going beyond RPA and directions of further development will be discussed.

  16. Electro-optical properties of photochemically stable polymer-stabilized blue-phase material

    Energy Technology Data Exchange (ETDEWEB)

    Chojnowska, O., E-mail: ochojnowska@wat.edu.pl; Dąbrowski, R. [Institute of Chemistry, Military University of Technology, Warsaw 00-908 (Poland); Yan, J.; Chen, Y.; Wu, S. T. [College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816 (United States)

    2014-12-07

    Polymer-stabilized blue-phase liquid crystal (BPLC) comprising fluorinated compounds with high resistivity and photochemical stability is demonstrated. The Kerr constant, driving voltage, and response time of this BPLC are measured using an in-plane switching liquid crystal cell. At 20 °C, the measured total response time is faster than 0.7 ms and Kerr constant is 2 nm/V{sup 2}. This fluorinated BPLC material is a promising candidate for next-generation photonic and display devices, because it can be used in active matrix addressed devices.

  17. Low-power switching of phase-change materials with carbon nanotube electrodes.

    Science.gov (United States)

    Xiong, Feng; Liao, Albert D; Estrada, David; Pop, Eric

    2011-04-29

    Phase-change materials (PCMs) are promising candidates for nonvolatile data storage and reconfigurable electronics, but high programming currents have presented a challenge to realize low-power operation. We controlled PCM bits with single-wall and small-diameter multi-wall carbon nanotubes. This configuration achieves programming currents of 0.5 microampere (set) and 5 microamperes (reset), two orders of magnitude lower than present state-of-the-art devices. Pulsed measurements enable memory switching with very low energy consumption. Analysis of over 100 devices finds that the programming voltage and energy are highly scalable and could be below 1 volt and single femtojoules per bit, respectively.

  18. Impact-induced tensile waves in a kind of phase-transforming materials

    CERN Document Server

    Huang, Shou-Jun

    2010-01-01

    This paper concerns the global propagation of impact-induced tensile waves in a kind of phase-transforming materials. It is well-known that the governing system of partial differential equations is hyperbolic-elliptic and the initial-boundary value problem is not well-posed at all levels of loading. By making use of fully nonlinear stress-strain curve to model this material, Dai and Kong succeeded in constructing a physical solution of the above initial-boundary value problem. For the impact of intermediate range, they assumed that $\\beta<3\\alpha$ in the stress-response function for simplicity. In this paper, we revisit the impact problem and consider the propagation of impact-induced tensile waves for all values of the parameters $\\alpha$ and $\\beta$. The physical solutions for all levels of loading are obtained completely.

  19. Phase Change Material Based Accumulation Panels in Combination with Renewable Energy Sources and Thermoelectric Cooling

    Directory of Open Access Journals (Sweden)

    Jan Skovajsa

    2017-01-01

    Full Text Available The article deals with the use of modern materials and technologies that can improve the thermal comfort in buildings. The article describes the design and usage of a special accumulation device, which is composed of thermal panels based on phase change materials (PCMs. The thermal panels have an integrated tube heat exchanger and heating foils. The technology can be used as a passive or active system for heating and cooling. It is designed as a “green technology”, so it is able to use renewable energy sources, e.g., photovoltaic (PV panels, solar thermal collectors and heat pumps. Moreover, an interesting possibility is the ability to use thermoelectric coolers. In the research, measurements of the different operating modes were made, and the results are presented in the text. The measurement approves that the technology improves the thermal capacity of the building, and it is possible to use it for active heating and cooling.

  20. Feasibility of using phase change materials to control the heat of hydration in massive concrete structures.

    Science.gov (United States)

    Choi, Won-Chang; Khil, Bae-Soo; Chae, Young-Seok; Liang, Qi-Bo; Yun, Hyun-Do

    2014-01-01

    This paper presents experimental results that can be applied to select a possible phase change material (PCM), such as a latent heat material (LHM), to control the hydration heat in mass concrete structures. Five experimental tests (microconduction, simplified adiabatic temperature rise, heat, and compressive strength tests) were conducted to select the most desirable LHM out of seven types of inorganic PCM used in cement mortar and to determine the most suitable mix design. The results of these experimental tests were used to assess the feasibility of using PCM to reduce hydration heat in mass concrete that was examined. The experimental results show that cement mortar containing barium- [Ba(OH)2 · 8H2O] based PCM has the lowest amount of total hydration heat of the cement pastes. The barium-based PCM provides good latent heat properties that help to prevent volume change and microcracks caused by thermal stress in mass concrete.

  1. Diffusion, Thermal Properties and Chemical Compatibilities of Select MAX Phases with Materials For Advanced Nuclear Systems

    Energy Technology Data Exchange (ETDEWEB)

    Barsoum, Michel [Drexel Univ., Philadelphia, PA (United States); Bentzel, Grady [Drexel Univ., Philadelphia, PA (United States); Tallman, Darin J. [Drexel Univ., Philadelphia, PA (United States); Sindelar, Robert [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Garcia-Diaz, Brenda [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hoffman, Elizabeth [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-04-04

    The demands of Gen IV nuclear power plants for long service life under neutron irradiation at high temperature are severe. Advanced materials that would withstand high temperatures (up to 1000+ ºC) to high doses in a neutron field would be ideal for reactor internal structures and would add to the long service life and reliability of the reactors. The objective of this work is to investigate the chemical compatibility of select MAX with potential materials that are important for nuclear energy, as well as to measure the thermal transport properties as a function of neutron irradiation. The chemical counterparts chosen for this work are: pyrolytic carbon, SiC, U, Pd, FLiBe, Pb-Bi and Na, the latter 3 in the molten state. The thermal conductivities and heat capacities of non-irradiated MAX phases will be measured.

  2. IFMIF-KEP. International fusion materials irradiation facility key element technology phase report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-03-01

    The International Fusion Materials Irradiation Facility (IFMIF) is an accelerator-based D-Li neutron source designed to produce an intense neutron field that will simulate the neutron environment of a D-T fusion reactor. IFMIF will provide a neutron flux equivalent to 2 MW/m{sup 2}, 20 dpa/y in Fe, in a volume of 500 cm{sup 3} and will be used in the development and qualification of materials for fusion systems. The design activities of IFMIF are performed under an IEA collaboration which began in 1995. In 2000, a three-year Key Element Technology Phase (KEP) of IFMIF was undertaken to reduce the key technology risk factors. This KEP report describes the results of the three-year KEP activities in the major project areas of accelerator, target, test facilities and design integration. (author)

  3. Design of a Protection Thermal Energy Storage Using Phase Change Material Coupled to a Solar Receiver

    Science.gov (United States)

    Verdier, D.; Falcoz, Q.; Ferrière, A.

    2014-12-01

    Thermal Energy Storage (TES) is the key for a stable electricity production in future Concentrated Solar Power (CSP) plants. This work presents a study on the thermal protection of the central receiver of CSP plant using a tower which is subject to considerable thermal stresses in case of cloudy events. The very high temperatures, 800 °C at design point, impose the use of special materials which are able to resist at high temperature and high mechanical constraints and high level of concentrated solar flux. In this paper we investigate a TES coupling a metallic matrix drilled with tubes of Phase Change Material (PCM) in order to store a large amount of thermal energy and release it in a short time. A numerical model is developed to optimize the arrangement of tubes into the TES. Then a methodology is given, based from the need in terms of thermal capacity, in order to help the choice of the geometry.

  4. Feasibility of Using Phase Change Materials to Control the Heat of Hydration in Massive Concrete Structures

    Directory of Open Access Journals (Sweden)

    Won-Chang Choi

    2014-01-01

    Full Text Available This paper presents experimental results that can be applied to select a possible phase change material (PCM, such as a latent heat material (LHM, to control the hydration heat in mass concrete structures. Five experimental tests (microconduction, simplified adiabatic temperature rise, heat, and compressive strength tests were conducted to select the most desirable LHM out of seven types of inorganic PCM used in cement mortar and to determine the most suitable mix design. The results of these experimental tests were used to assess the feasibility of using PCM to reduce hydration heat in mass concrete that was examined. The experimental results show that cement mortar containing barium- [Ba(OH2·8H2O] based PCM has the lowest amount of total hydration heat of the cement pastes. The barium-based PCM provides good latent heat properties that help to prevent volume change and microcracks caused by thermal stress in mass concrete.

  5. Ternary mixture of fatty acids as phase change materials for thermal energy storage applications

    Directory of Open Access Journals (Sweden)

    Karunesh Kant

    2016-11-01

    Full Text Available The present study deals with the development of ternary mixtures of fatty acids for low temperature thermal energy storage applications. The commercial grade fatty acids such as Capric Acid (CA, Lauric Acid (LA, Palmitic Acid (PA and Stearic Acid (SA, have been used to prepare stable, solid–liquid phase change material (PCM for the same. In this regard, a series of ternary mixture i.e. CA–LA–SA (CLS and CA–PA–SA (CPS have been developed with different weight percentages. Thermal characteristics of these developed ternary mixture i.e. melting temperature and latent heat of fusion have been measured by using Differential Scanning Calorimeter (DSC technique. The synthesized materials are found to have melting temperature in the range of 14–21 °C (along with adequate amount of latent heat of fusion, which may be quite useful for several low temperature thermal energy storage applications.

  6. Photosynthetic Reaction Centers as Active Molecular Electronic Components. Phase I

    Science.gov (United States)

    1993-08-13

    SDS bring to 1 liter with H20, pH to 8.3 10% APS = 10% (w/v) Ammonium persulfate Assemble gel plates and spacers (how depends on apparatus). Mix up...the synthesis of polypyrrole microtubules in 12 Biological Components Corporation Phase I Final Report SBIR ARMY 92-103 commercially available

  7. Phase Change Materials (PCM) fabricated in vertical structures for reconfigurable and tunable circuits

    Science.gov (United States)

    Barajas, Eduardo; Coutu, Ronald A.

    2014-03-01

    Germanium Telluride (GeTe) can be described as a non-volatile (latching state) phase change material (PCM) in memory applications. GeTe also exhibits a volatile (reversible state) region when heated and cooled between 100-180 °C. At temperatures higher than 185 °C the material crystallizes and "latches" until a temperature near to its melting point (725 °C) is reached and cooled rapidly (quenching). Germanium Antimony Telluride (GeSbTe) or also known as GST has similar characteristics as GeTe. GST also exhibits a volatile (reversible state) region when heated and cooled between 100-150 °C. GST crystallizes at 155 °C and its melting point is 600 °C. This paper demonstrates the feasibility of fabricating radio frequency (RF) devices of phase change materials (PCM) and it also presents a comparison between amorphous and crystalline PCMs in the RF spectrum. Previous work focuses on exploiting GeTe and GST as nonvolatile materials in memory applications, and also on characterizing them for their electrical and mechanical properties. The approach here focuses on fabricating RF devices and analyzing their responses. A simulation with resistor-capacitor (RC) and resistor-inductor (RL) circuits is presented to represent the response of the RF devices under testing. The fabrication process includes two-layer and four-layer devices on the Si wafer. PCMs are sputtered and the test pads are deposited using electron beam evaporation. Results show that these RF devices alone can serve as a low pass filter with a cutoff frequency of 10 MHz.

  8. Polymer-coated fibrous materials as the stationary phase in packed capillary gas chromatography.

    Science.gov (United States)

    Saito, Yoshihiro; Tahara, Ai; Imaizumi, Motohiro; Takeichi, Tsutomu; Wada, Hiroo; Jinno, Kiyokatsu

    2003-10-15

    Synthetic polymer filaments have been introduced as the support material in packed capillary gas chromatography (GC). The filaments of the heat-resistant polymers, Zylon, Kevlar, Nomex, and Technora, were longitudinally packed into a short fused-silica capillary, followed by the conventional coating process for open-tubular GC columns. The separation of several test mixtures such as n-alkylbenzenes and n-alkanes was carried out with these polymer-coated fiber-packed capillary columns. With the coating by various polymeric materials on the surface of these filaments, the retentivity was significantly improved over the parent fiber-packed column (without polymer coating) as well as a conventional open-tubular capillary of the same length. The results demonstrated a good combination of Zylon as the support and poly(dimethylsiloxane)-based materials as the coating liquid-phase for the successful GC separation of n-alkanes and polycyclic aromatic hydrocarbons (PAHs), while successful applications for other separations such as poly(ethylene glycol) coating for the separation of alcohols were also obtained. From the results it has been suggested that the selectivity of the fiber-packed column could be tuned by selecting different coating materials, indicating the promising possibility for a novel usage of fine fibrous polymers as the support material that can be combined with newly synthesized coating materials specially designed for particular separations. Taking advantage of good thermal stability of the fibers, the column temperature could be elevated to higher than 350 degrees C with the combination of a short metallic capillary.

  9. Preparation of shape-stabilized phase change materials as temperature-adjusting powder

    Institute of Scientific and Technical Information of China (English)

    MIAO Chunyan; L(U) Gang; YAO Youwei; TANG Guoyi; WENG Duan

    2007-01-01

    The shape-stabilized phase change materials (PCMs)composed of paraffin wax and silica were prepared in O/W emulsion with cetyl trimethylamine bromide as emulsifier and n-pentanol as assist emulsifier.The paraffin wax(with melting temperature of 29℃,crystallizing temperature of 26℃ and latent heat of 142 J/g)served as latent heat storage material and the silica as supporting material,which prevented the leakage of the melted paraffin wax.Silica supporting material was formed in situ via hydrolysis and condensation from low-cost sodium silicate solution with chlorhydric acid and ammonium bicarbonate as neutralizing agent.The thermogravimetry(TG)curves show that the composite has a thermal stability superior to that of paraffin wax and that the content of paraffin wax in the composite is 65wt%.The maximum latent heat and its relevant melting point of composite are 95 J/g and 30℃,respectively.

  10. Preparation, characterization, and thermal properties of microencapsulated phase change material for thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Alkan, Cemil; Sari, Ahmet; Karaipekli, Ali [Department of Chemistry, Gaziosmanpasa University, 60240 Tokat (Turkey); Uzun, Orhan [Department of Physics, Gaziosmanpasa University, 60240 Tokat (Turkey)

    2009-01-15

    This study is focused on the preparation, characterization, and determination of thermal properties of microencapsulated docosane with polymethylmethacrylate (PMMA) as phase change material for thermal energy storage. Microencapsulation of docosane has been carried out by emulsion polymerization. The microencapsulated phase change material (MEPCM) was characterized using scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. Thermal properties and thermal stability of MEPCM were measured by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). DSC analysis indicated that the docosane in the microcapsules melts at 41.0 C and crystallizes at 40.6 C. It has latent heats of 54.6 and -48.7 J/g for melting and crystallization, respectively. TGA showed that the MEPCM degraded in three distinguishable steps and had good chemical stability. Accelerated thermal cycling tests also indicated that the MEPCM had good thermal reliability. Based on all these results, it can be concluded that the microencapsulated docosane as MEPCMs have good potential for thermal energy storage purposes such as solar space heating applications. (author)

  11. A novel quantitative imaging technique for material differentiation based on differential phase contrast CT

    Science.gov (United States)

    Qi, Zhihua; Zambelli, Joseph; Bevins, Nicholas; Chen, Guang-Hong

    2010-04-01

    Compared to single energy CT, which provides information only about the x-ray linear attenuation coefficients, dual energy CT is able to obtain the electron density and effective atomic number for different materials in a quantitative way. In this study, as an alternative to dual energy CT, a novel quantitative imaging method based on phase contrast CT is described. Rather than requiring two scans with different x-ray photon energies, diffraction grating-based phase contrast CT is capable of reconstructing images of both the linear attenuation and refractive index decrement from a single scan. From the two images, quantitative information of both the electron density and effective atomic number can be extracted. Experimental results demonstrate that: (1) electron density can be accurately determined from refractive index decrement through a linear relationship; and (2) effective atomic number can be explicitly derived from the ratio of linear attenuation to refractive index decrement, using a simple function, i.e., a power function plus a constant. The presented method will shed insight into the field of material separation and find its use in medical and non-medical applications.

  12. Influence of deformation on structural-phase state of weld material in St3 steel

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, Alexander, E-mail: galvas.kem@gmail.ru; Ababkov, Nicolay, E-mail: n.ababkov@rambler.ru; Ozhiganov, Yevgeniy, E-mail: zhigan84@mail.ru [Kuzbass State Technical University, 25-54, Krasnaya Str., 650000, Kemerovo (Russian Federation); LLC “Kuzbass Center of Welding and Control”, 33/2, Lenin Str., 650055, Kemerovo (Russian Federation); Kozlov, Eduard, E-mail: kozlov@tsuab.ru [Kuzbass State Technical University, 25-54, Krasnaya Str., 650000, Kemerovo (Russian Federation); Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); Popova, Natalya, E-mail: natalya-popova-44@mail.ru [Kuzbass State Technical University, 25-54, Krasnaya Str., 650000, Kemerovo (Russian Federation); Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); Institute of Strength Physics and Materials Science, SB RAS, 2/4, Akademicheskii Ave., 634021, Tomsk (Russian Federation); Nikonenko, Elena, E-mail: vilatomsk@mail.ru [Kuzbass State Technical University, 25-54, Krasnaya Str., 650000, Kemerovo (Russian Federation); Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); National Research Tomsk Polytechnic University, 30, Lenin Str., 634050, Tomsk (Russian Federation); Zboykova, Nadezhda, E-mail: tezaurusn@gmail.com; Koneva, Nina, E-mail: koneva@tsuab.ru [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation)

    2016-01-15

    The structural-phase condition of the weld material subjected to the plastic deformation was investigated using the translucent diffraction electron microscopy method. The investigations were carried out near the joint of the weld and the base metal. The seam was done by the method of manual arc welding without artificial defects. The St3 steel was taken as the welded material. Influence of the plastic deformation on morphology, phase composition, defect structure and its parameters of weld metal was revealed. All investigations were done at the distance of 0.5 mm from the joint of the weld and the base metal at the deformation degrees from 0 to 5% and after destruction of a sample. It was established that deformation of the sample did not lead to qualitative changes in the structure (the structure is still presented by ferrite-pearlite mixture) but changed the quantitative parameters of the structure, namely, with the increase of plastic deformation a part of the pearlite component becomes more and more imperfect. In the beginning it turns into the destroyed pearlite then into ferrite, the volume fraction of pearlite is decreased. The polarization of dislocation structure takes place but it doesn’t lead to the internal stresses that can destroy the sample.

  13. Reversible optical switching of highly confined phonon-polaritons with an ultrathin phase-change material

    Science.gov (United States)

    Li, Peining; Yang, Xiaosheng; Maß, Tobias W. W.; Hanss, Julian; Lewin, Martin; Michel, Ann-Katrin U.; Wuttig, Matthias; Taubner, Thomas

    2016-08-01

    Surface phonon-polaritons (SPhPs), collective excitations of photons coupled with phonons in polar crystals, enable strong light-matter interaction and numerous infrared nanophotonic applications. However, as the lattice vibrations are determined by the crystal structure, the dynamical control of SPhPs remains challenging. Here, we realize the all-optical, non-volatile, and reversible switching of SPhPs by controlling the structural phase of a phase-change material (PCM) employed as a switchable dielectric environment. We experimentally demonstrate optical switching of an ultrathin PCM film (down to 7 nm, detect ultra-confined SPhPs (polariton wavevector kp > 70k0, k0 = 2π/λ) in quartz. Our proof of concept allows the preparation of all-dielectric, rewritable SPhP resonators without the need for complex fabrication methods. With optimized materials and parallelized optical addressing we foresee application potential for switchable infrared nanophotonic elements, for example, imaging elements such as superlenses and hyperlenses, as well as reconfigurable metasurfaces and sensors.

  14. Investigation of Thermal Interface Materials Using Phase-Sensitive Transient Thermoreflectance Technique: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Feng, X.; King, C.; DeVoto, D.; Mihalic, M.; Narumanchi, S.

    2014-08-01

    With increasing power density in electronics packages/modules, thermal resistances at multiple interfaces are a bottleneck to efficient heat removal from the package. In this work, the performance of thermal interface materials such as grease, thermoplastic adhesives and diffusion-bonded interfaces are characterized using the phase-sensitive transient thermoreflectance technique. A multi-layer heat conduction model was constructed and theoretical solutions were derived to obtain the relation between phase lag and the thermal/physical properties. This technique enables simultaneous extraction of the contact resistance and bulk thermal conductivity of the TIMs. With the measurements, the bulk thermal conductivity of Dow TC-5022 thermal grease (70 to 75 um bondline thickness) was 3 to 5 W/(m-K) and the contact resistance was 5 to 10 mm2-K/W. For the Btech thermoplastic material (45 to 80 μm bondline thickness), the bulk thermal conductivity was 20 to 50 W/(m-K) and the contact resistance was 2 to 5 mm2-K/W. Measurements were also conducted to quantify the thermal performance of diffusion-bonded interface for power electronics applications. Results with the diffusion-bonded sample showed that the interfacial thermal resistance is more than one order of magnitude lower than those of traditional TIMs, suggesting potential pathways to efficient thermal management.

  15. CFD ANALYSIS FOR HEAT TRANSFER BETWEEN COPPER ENCAPSULATED PHASE CHANGE MATERIAL AND HEAT TRANSFER FLUID

    Directory of Open Access Journals (Sweden)

    M.Premkumar

    2013-03-01

    Full Text Available Heat transfer plays an important role in the enhancement of thermal energy storage in phase change material (PCM. The effective utilization of solar thermal energy can be obtained by proper storage of that energy. There are various techniques for the enhancement solar thermal storage in phase change material such as introductionof wire brushes, honey comb structure, fins and packed bed storage. In this study the analysis of heat transfer between PCM and heat transfer fluids (HTF with Spherical and cylindrical finned encapsulations made of copper are done using computational fluid dynamic (CFD analysis software GAMBIT and Fluent 6.2. The analysis is done in two modes as charging and discharging. During the charging mode the input is given in terms of temperature to the heat transfer fluid and the amount of heat transfer inside the PCM encapsulation is taken as output. During the discharging process the output temperature in the PCM is given as input and the amount of heat transferred to the heat transfer fluid is noted. The results from CFD analysis conclude that the heat transfer is more in finned encapsulations than that of without finned encapsulations and the copper sphere with fins is considered to be the best out of all other encapsulations.

  16. Phase inversion of particle-stabilized materials from foams to dry water.

    Science.gov (United States)

    Binks, Bernard P; Murakami, Ryo

    2006-11-01

    Small particles attached to liquid surfaces arise in many products and processes, including crude-oil emulsions and food foams and in flotation, and there is a revival of interest in studying their behaviour. Colloidal particles of suitable wettability adsorb strongly to liquid-liquid and liquid-vapour interfaces, and can be sole stabilizers of emulsions and foams, respectively. New materials, including colloidosomes, anisotropic particles and porous solids, have been prepared by assembling particles at such interfaces. Phase inversion of particle-stabilized emulsions from oil in water to water in oil can be achieved either by variation of the particle hydrophobicity (transitional) or by variation of the oil/water ratio (catastrophic). Here we describe the phase inversion of particle-stabilized air-water systems, from air-in-water foams to water-in-air powders and vice versa. This inversion can be driven either by a progressive change in silica-particle hydrophobicity at constant air/water ratio or by changing the air/water ratio at fixed particle wettability, and has not been observed in the corresponding systems stabilized by surfactants. The simplicity of the work is that this novel inversion is achieved in a single system. The resultant materials in which either air or water become encapsulated have potential applications in the food, pharmaceutical and cosmetics industries.

  17. Max Phase Materials And Coatings For High Temperature Heat Transfer Applications

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Rodriguez, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Garcia-Diaz, B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Olson, L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Fuentes, R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Sindelar, R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-19

    Molten salts have been used as heat transfer fluids in a variety of applications within proposed Gen IV nuclear designs and in advanced power system such as Concentrating Solar Power (CSP). However, operating at elevated temperatures can cause corrosion in many materials. This work developed coating technologies for MAX phase materials on Haynes-230 and characterized the corrosion of the coatings in the presence of commercial MgCl2-KCl molten salt. Cold spraying of Ti2AlC and physical vapor deposition (PVD) of Ti2AlC or Zr2AlC were tested to determine the most effective form of coating MAX phases on structural substrates. Corrosion testing at 850°C for 100 hrs showed that 3.9 μm Ti2AlC by PVD was slightly protective while 117 μm Ti2AlC by cold spray and 3.6 μm Zr2AlC by PVD were completely protective. None of the tests showed decomposition of the coating (Ti or Zr) into the salt

  18. Thermoelectric generators incorporating phase-change materials for waste heat recovery from engine exhaust

    Science.gov (United States)

    Meisner, Gregory P; Yang, Jihui

    2014-02-11

    Thermoelectric devices, intended for placement in the exhaust of a hydrocarbon fuelled combustion device and particularly suited for use in the exhaust gas stream of an internal combustion engine propelling a vehicle, are described. Exhaust gas passing through the device is in thermal communication with one side of a thermoelectric module while the other side of the thermoelectric module is in thermal communication with a lower temperature environment. The heat extracted from the exhaust gasses is converted to electrical energy by the thermoelectric module. The performance of the generator is enhanced by thermally coupling the hot and cold junctions of the thermoelectric modules to phase-change materials which transform at a temperature compatible with the preferred operating temperatures of the thermoelectric modules. In a second embodiment, a plurality of thermoelectric modules, each with a preferred operating temperature and each with a uniquely-matched phase-change material may be used to compensate for the progressive lowering of the exhaust gas temperature as it traverses the length of the exhaust pipe.

  19. Properties of Mechanically Alloyed W-Ti Materials with Dual Phase Particle Dispersion

    Directory of Open Access Journals (Sweden)

    František Lukáč

    2016-12-01

    Full Text Available W alloys are currently widely studied materials for their potential application in future fusion reactors. In the presented study, we report on the preparation and properties of mechanically alloyed W-Ti powders compacted by pulsed electric current sintering. Four different powder compositions of W-(3%–7%Ti with Hf or HfC were prepared. The alloys’ structure contains only high-melting-point phases, namely the W-Ti matrix, complex carbide (Ti,W,HfC and HfO2 particle dispersion; Ti in the form of a separate phase is not present. The bending strength of the alloys depends on the amount of Ti added. The addition of 3 wt. % Ti led to an increase whereas 7 wt. % Ti led to a major decrease in strength when compared to unalloyed tungsten sintered at similar conditions. The addition of Ti significantly lowered the room-temperature thermal conductivity of all prepared materials. However, unlike pure tungsten, the conductivity of the prepared alloys increased with the temperature. Thus, the thermal conductivity of the alloys at 1300 °C approached the value of the unalloyed tungsten.

  20. Phase inversion of particle-stabilized materials from foams to dry water

    Science.gov (United States)

    Binks, Bernard P.; Murakami, Ryo

    2006-11-01

    Small particles attached to liquid surfaces arise in many products and processes, including crude-oil emulsions and food foams and in flotation, and there is a revival of interest in studying their behaviour. Colloidal particles of suitable wettability adsorb strongly to liquid-liquid and liquid-vapour interfaces, and can be sole stabilizers of emulsions and foams, respectively. New materials, including colloidosomes, anisotropic particles and porous solids, have been prepared by assembling particles at such interfaces. Phase inversion of particle-stabilized emulsions from oil in water to water in oil can be achieved either by variation of the particle hydrophobicity (transitional) or by variation of the oil/water ratio (catastrophic). Here we describe the phase inversion of particle-stabilized air-water systems, from air-in-water foams to water-in-air powders and vice versa. This inversion can be driven either by a progressive change in silica-particle hydrophobicity at constant air/water ratio or by changing the air/water ratio at fixed particle wettability, and has not been observed in the corresponding systems stabilized by surfactants. The simplicity of the work is that this novel inversion is achieved in a single system. The resultant materials in which either air or water become encapsulated have potential applications in the food, pharmaceutical and cosmetics industries.

  1. OCV Hysteresis in Li-Ion Batteries including Two-Phase Transition Materials

    Directory of Open Access Journals (Sweden)

    Michael A. Roscher

    2011-01-01

    Full Text Available The relation between batteries' state of charge (SOC and open-circuit voltage (OCV is a specific feature of electrochemical energy storage devices. Especially NiMH batteries are well known to exhibit OCV hysteresis, and also several kinds of lithium-ion batteries show OCV hysteresis, which can be critical for reliable state estimation issues. Electrode potential hysteresis is known to result from thermodynamical entropic effects, mechanical stress, and microscopic distortions within the active electrode materials which perform a two-phase transition during lithium insertion/extraction. Hence, some Li-ion cells including two-phase transition active materials show pronounced hysteresis referring to their open-circuit voltage. This work points out how macroscopic effects, that is, diffusion limitations, superimpose the latte- mentioned microscopic mechanisms and lead to a shrinkage of OCV hysteresis, if cells are loaded with high current rates. To validate the mentioned interaction, Li-ion cells' state of charge is adjusted to 50% with various current rates, beginning from the fully charged and the discharged state, respectively. As a pronounced difference remains between the OCV after charge and discharge adjustment, obviously the hysteresis vanishes as the target SOC is adjusted with very high current rate.

  2. Shock-Driven Hydrodynamic Instability Growth Near Phase Boundaries and Material Property Transitions: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Peralta, Pedro [Arizona State Univ., Tempe, AZ (United States); Fortin, Elizabeth [Arizona State Univ., Tempe, AZ (United States); Opie, Saul [Arizona State Univ., Tempe, AZ (United States); Gautam, Sudrishti [Arizona State Univ., Tempe, AZ (United States); Gopalakrishnan, Ashish [Arizona State Univ., Tempe, AZ (United States); Lynch, Jenna [Arizona State Univ., Tempe, AZ (United States); Chen, Yan [Arizona State Univ., Tempe, AZ (United States); Loomis, Eric [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-01

    Activities for this grant included: 1) Development of dynamic impact experiments to probe strength and phase transition influence on dynamic deformation, 2) development of modern strength and phase aware simulation capabilities, 3) and post-processing of experimental data with simulation and closed form analytical techniques. Two different dynamic experiments were developed to probe material strengths in solid metals (largely copper and iron in this effort). In the first experiment a flyer plate impacts a flat target with an opposite rippled surface that is partially supported by a weaker window material. Post mortem analysis of the target sample showed a strong and repeatable residual plastic deformation dependence on grain orientation. Yield strengths for strain rates near 105 s-1 and plastic strains near ~50% were estimated to be around 180 to 240 MPa, varying in this range with grain orientation. Unfortunately dynamic real-time measurements were difficult with this setup due to diagnostic laser scattering; hence, an additional experimental setup was developed to complement these results. In the second set of experiments a rippled surface was ablated by a controlled laser pulsed, which launched a rippled shock front to an opposite initially flat diagnostic surface that was monitored in real-time with spatially resolved velocimetry techniques, e.g., line VISAR in addition to Transient Imaging Displacement Interferometry (TIDI) displacement measurements. This setup limited the displacements at the diagnostic surface to a reasonable level for TIDI measurements (~ less than one micrometer). These experiments coupled with analytical and numerical solutions provided evidence that viscous and elastic deviatoric strength affect shock front perturbation evolution in clearly different ways. Particularly, normalized shock front perturbation amplitudes evolve with viscosity (η) and perturbation wavelength (λ) as η/λ, such that increasing viscosity

  3. Heat Transfer of Heat Sinking Vest with Phase-change Material

    Institute of Scientific and Technical Information of China (English)

    QIU Yifen; JIANG Nan; WU Wei; ZHANG Guangwei; XIAO Baoliang

    2011-01-01

    To investigate thermal protection effects of heat sinking vest with phase-change material (PCM),human thermoregulation model is introduced,and a thermal mathematical model of heat transfer with phase change has been developed with the enthalpy method.The uniform energy equation is constructed for the whole domain,and the equation is implicitly discreted by control volume and finite difference method.Then the enthalpy in each node is solved by using chasing method to calculate the tridiagonal equations,and the inner surface temperature of PCM could be obtained.According to the human thermoregulation model of heat sinking vest,the dynamic temperature distribution and sweat of the body are solved.Calculation results indicate that the change of core temperature matches the experimental result,and the sweat difference is small.This thermal mathematical model of heat transfer with phase change is credible and appropriate.Through comparing the dynamic temperature distribution and sweat of the body wearing heat sinking vest to results of the body not wearing this clothing,it is evident that wearing heat sinking vest can reduce the body heat load significantly.

  4. Microstructure and magnetic behavior of Mn doped GeTe chalcogenide semiconductors based phase change materials

    Science.gov (United States)

    Adam, Adam Abdalla Elbashir; Cheng, Xiaomin; Abuelhassan, Hassan H.; Miao, Xiang Shui

    2017-06-01

    Phase-change materials (PCMs) are the most promising candidates to be used as an active media in the universal data storage and spintronic devices, due to their large differences in physical properties of the amorphous-crystalline phase transition behavior. In the present study, the microstructure, magnetic and electrical behaviors of Ge0.94Mn0.06Te thin film were investigated. The crystallographic structure of Ge0.94Mn0.06Te thin film was studied sing X-ray diffractometer (XRD) and High Resolution Transmission Electron Microscope (HR-TEM). The XRD pattern showed that the crystallization structure of the film was rhombohedral phase for GeTe with a preference (202) orientation. The HR-TEM image of the crystalline Ge0.94Mn0.06Te thin film demonstrated that, there were two large crystallites and small amorphous areas. The magnetization as a function of the magnetic field analyses of both amorphous and crystalline states showed the ferromagnetic hysteretic behaviors. Then, the hole carriers concentration of the film was measured and it found to be greater than 1021 cm-3 at room temperature. Moreover, the anomalous of Hall Effect (AHE) was clearly observed for the measuring temperatures 5, 10 and 50 K. The results demonstrated that the magnitude of AHE decreased when the temperature was increasing.

  5. Control over emissivity of zero-static-power thermal emitters based on phase changing material GST

    CERN Document Server

    Du, Kaikai; Lyu, Yanbiao; Ding, Jichao; Lu, Yue; Cheng, Zhiyuan; Qiu, Min

    2016-01-01

    Controlling the emissivity of a thermal emitter has attracted growing interest with a view towards a new generation of thermal emission devices. So far, all demonstrations have involved sustained external electric or thermal consumption to maintain a desired emissivity. Here control over the emissivity of a thermal emitter consisting of a phase changing material Ge2Sb2Te5 (GST) film on top of a metal film is demonstrated. This thermal emitter shows broad wavelength-selective spectral emissivity in the mid-infrared. The peak emissivity approaches the ideal blackbody maximum and a maximum extinction ratio of above 10dB is attainable by switching GST between the crystalline and amorphous phases. By controlling the intermediate phases, the emissivity can be continuously tuned. This switchable, tunable, wavelength-selective and thermally stable thermal emitter will pave the way towards the ultimate control of thermal emissivity in the field of fundamental science as well as for energy-harvesting and thermal contro...

  6. The ω-SQUIPT as a tool to phase-engineer Josephson topological materials

    Science.gov (United States)

    Strambini, E.; D'Ambrosio, S.; Vischi, F.; Bergeret, F. S.; Nazarov, Yu. V.; Giazotto, F.

    2016-12-01

    Multi-terminal superconducting Josephson junctions based on the proximity effect offer the opportunity to tailor non-trivial quantum states in nanoscale weak links. These structures can realize exotic topologies in several dimensions, for example, artificial topological superconductors that are able to support Majorana bound states, and pave the way to emerging quantum technologies and future quantum information schemes. Here we report the realization of a three-terminal Josephson interferometer based on a proximized nanosized weak link. Our tunnelling spectroscopy measurements reveal transitions between gapped (that is, insulating) and gapless (conducting) states that are controlled by the phase configuration of the three superconducting leads connected to the junction. We demonstrate the topological nature of these transitions: a gapless state necessarily occurs between two gapped states of different topological indices, in much the same way that the interface between two insulators of different topologies is necessarily conducting. The topological numbers that characterize such gapped states are given by superconducting phase windings over the two loops that form the Josephson interferometer. As these gapped states cannot be transformed to one another continuously without passing through a gapless condition, they are topologically protected. The same behaviour is found for all of the points of the weak link, confirming that this topology is a non-local property. Our observation of the gapless state is pivotal for enabling phase engineering of different and more sophisticated artificial topological materials.

  7. Integrity of the Pericentriolar Material Is Essential for Maintaining Centriole Association during M Phase.

    Directory of Open Access Journals (Sweden)

    Mi Young Seo

    Full Text Available A procentriole is assembled next to the mother centriole during S phase and remains associated until M phase. After functioning as a spindle pole during mitosis, the mother centriole and procentriole are separated at the end of mitosis. A close association of the centriole pair is regarded as an intrinsic block to the centriole reduplication. Therefore, deregulation of this process may cause a problem in the centriole number control, resulting in increased genomic instability. Despite its importance for faithful centriole duplication, the mechanism of centriole separation is not fully understood yet. Here, we report that centriole pairs are prematurely separated in cells whose cell cycle is arrested at M phase by STLC. Dispersal of the pericentriolar material (PCM was accompanied. This phenomenon was independent of the separase activity but needed the PLK1 activity. Nocodazole effectively inhibited centriole scattering in STLC-treated cells, possibly by reducing the microtubule pulling force around centrosomes. Inhibition of PLK1 also reduced the premature separation of centrioles and the PCM dispersal as well. These results revealed the importance of PCM integrity in centriole association. Therefore, we propose that PCM disassembly is one of the driving forces for centriole separation during mitotic exit.

  8. Transient Structures and Possible Limits of Data Recording in Phase-Change Materials.

    Science.gov (United States)

    Hu, Jianbo; Vanacore, Giovanni M; Yang, Zhe; Miao, Xiangshui; Zewail, Ahmed H

    2015-07-28

    Phase-change materials (PCMs) represent the leading candidates for universal data storage devices, which exploit the large difference in the physical properties of their transitional lattice structures. On a nanoscale, it is fundamental to determine their performance, which is ultimately controlled by the speed limit of transformation among the different structures involved. Here, we report observation with atomic-scale resolution of transient structures of nanofilms of crystalline germanium telluride, a prototypical PCM, using ultrafast electron crystallography. A nonthermal transformation from the initial rhombohedral phase to the cubic structure was found to occur in 12 ps. On a much longer time scale, hundreds of picoseconds, equilibrium heating of the nanofilm is reached, driving the system toward amorphization, provided that high excitation energy is invoked. These results elucidate the elementary steps defining the structural pathway in the transformation of crystalline-to-amorphous phase transitions and describe the essential atomic motions involved when driven by an ultrafast excitation. The establishment of the time scales of the different transient structures, as reported here, permits determination of the possible limit of performance, which is crucial for high-speed recording applications of PCMs.

  9. Modified T-history method for measuring thermophysical properties of phase change materials at high temperature

    Science.gov (United States)

    Omaraa, Ehsan; Saman, Wasim; Bruno, Frank; Liu, Ming

    2017-06-01

    Latent heat storage using phase change materials (PCMs) can be used to store large amounts of energy in a narrow temperature difference during phase transition. The thermophysical properties of PCMs such as latent heat, specific heat and melting and solidification temperature need to be defined at high precision for the design and estimating the cost of latent heat storage systems. The existing laboratory standard methods, such as differential thermal analysis (DTA) and differential scanning calorimetry (DSC), use a small sample size (1-10 mg) to measure thermophysical properties, which makes these methods suitable for homogeneous elements. In addition, this small amount of sample has different thermophysical properties when compared with the bulk sample and may have limitations for evaluating the properties of mixtures. To avoid the drawbacks in existing methods, the temperature - history (T-history) method can be used with bulk quantities of PCM salt mixtures to characterize PCMs. This paper presents a modified T-history setup, which was designed and built at the University of South Australia to measure the melting point, heat of fusion, specific heat, degree of supercooling and phase separation of salt mixtures for a temperature range between 200 °C and 400 °C. Sodium Nitrate (NaNO3) was used to verify the accuracy of the new setup.

  10. Mechanism of GeSbTe phase change materials: an ab initio molecular dynamics study

    Science.gov (United States)

    Raty, Jean-Yves; Otjacques, Céline; Gaspard, Jean-Pierre; Bichara, Christophe

    2008-03-01

    Among phase change materials, Ge2Sb2Te5 (225) is one of the most successfully used in applications. Accepted models are based on EXAFS spectra and suppose a complete reorganization of bonds during amorphization, with Ge changing from sixfold to tetrahedral coordination. We perform ab initio MD simulations of the (225), (124) and (415) liquid alloys. We show that the crystalline, liquid and amorphous structure of these systems are similar, with very little sp3 hybridization around Ge atoms and a majority of p-sigma bonds. Using a set of quenched liquid configurations we reproduce the EXAFS measurements on the (225) composition and explain how the static Debye Waller factor due to the vacancies in the crystal phase leads to a cancellation of individual neighbors contribution to the EXAFS signal while in the amorphous, a larger coherence occurs, enhancing the EXAFS signal. The computed electrical conductivities of the three phases (cubic solid, liquid and amorphous) prove to be very different, accordingly with the experiment.

  11. Study on BSTO/MgO Ferroelectric Materials for Phase Shift Doped with Rare Earth Oxides

    Institute of Scientific and Technical Information of China (English)

    Yang Chunxia; Zhou Hongqing; Liu Min; Wu Hongzhong

    2005-01-01

    Barium strontium titanate/magnesia (BSTO/MgO) ferroelectric materials for phase shift were prepared by traditional ceramic process-solid phase synthesis. The effects of various rare earth oxides of 0.5% on dielectric behaviors of BSTO/MgO composites were studied in terms of permittivity, loss tangent and tunability both at low and high frequencies. The dielectric constant of Y2O3 and Er2O3 doped samples decreases from 160 to 120, and the microwave loss of La2O3 and Er2O3 doped samples decreases from 8.2×10-3 to 6.8×10-3. Only La2O3 increases the tunability of BSTO/MgO system, from 13.6% to 14.8%. For the La2O3 doped sample, the value of tunability is more than 14% with the external DC field 4000 V*mm-1 and the microwave loss at 2.47 GHz is 6.77×10-3 and, hence, it can basically meet the requirements of phase shifters working at microwave frequencies. The influence mechanism was discussed preliminarily.

  12. Thermal buffering performance of composite phase change materials applied in low-temperature protective garments

    Science.gov (United States)

    Yang, Kai; Jiao, Mingli; Yu, Yuanyuan; Zhu, Xueying; Liu, Rangtong; Cao, Jian

    2017-07-01

    Phase change material (PCM) is increasingly being applied in the manufacturing of functional thermo-regulated textiles and garments. This paper investigated the thermal buffering performance of different composite PCMs which are suitable for the application in functional low-temperature protective garments. First, according to the criteria selecting PCM for functional textiles/garments, three kinds of pure PCM were selected as samples, which were n-hexadecane, n-octadecane and n-eicosane. To get the adjustable phase change temperature range and higher phase change enthalpy, three kinds of composite PCM were prepared using the above pure PCM. To evaluate the thermal buffering performance of different composite PCM samples, the simulated low-temperature experiments were performed in the climate chamber, and the skin temperature variation curves in three different low temperature conditions were obtained. Finally composite PCM samples’ thermal buffering time, thermal buffering capacity and thermal buffering efficiency were calculated. Results show that the comprehensive thermal buffering performance of n-octadecane and n-eicosane composite PCM is the best.

  13. Designing dual phase sensing materials from polyaniline filled styrene–isoprene–styrene composites

    Energy Technology Data Exchange (ETDEWEB)

    Sadasivuni, Kishor Kumar, E-mail: kishor_kumars@yahoo.com [Centre for Advanced Materials, Qatar University, Doha (Qatar); Ponnamma, Deepalekshmi [School of Chemical Sciences, Mahatma Gandhi University, Kottayam 686560, Kerala (India); Kasak, Peter; Krupa, Igor; Ali S A Al-Maadeed, Mariam [Centre for Advanced Materials, Qatar University, Doha (Qatar)

    2014-10-15

    The demand for developing oil detectors is ever increasing since the cleanup and recovery from oil spill usually take long time. Here we propose oil sensors made of polyaniline (PANI) filled poly(styrene–isoprene–styrene) (SIS) block copolymer composite films with good uniformity and dispersion. The changes in resistivity of the samples in presence of both oil and water media reveal the good sensing ability of SIS–PANI films towards oil in water (dual phase). The morphology and chemical composition of the developed products are characterized by scanning electron microscopy and Fourier transformation infrared spectroscopy. Swelling studies are performed to correlate the sensing response to the structural variations and based on it a mechanism is derived for the dual phase sensing. Contact angle measurements confirm the behavior further. The thermal properties and crystallinity of the composites are also addressed by the thermogravimetric and differential scanning calorimetric studies. The developed oil sensor material is able to withstand extreme temperature condition as well. - Highlights: • We model a dual phase sensor capable of detecting oil in water. • A mechanism is proposed to correlate sensing with diffusion. • In situ polymerization helps in the uniform distribution of filler. • Polymer composite sensor could be used as stickers on oil pipelines.

  14. Modelling of phase change materials in the Toronto SUI net zero energy house using TRNSYS

    Energy Technology Data Exchange (ETDEWEB)

    Siddiqui, O.; Fung, A.; Zhang, D. [Ryerson Polytechnic Univ., Toronto, ON (Canada). Dept. of Mechanical and Industrial Engineering

    2008-08-15

    In the context of building applications, phase change materials (PCM), can be defined as any heat storage material that can absorb a large amount of thermal energy while undergoing a change in phase, such as from a solid to a liquid phase. The incorporation of PCM into the building envelope can enhance occupant comfort through the reduction of indoor temperature fluctuations. It has also been shown to cause a decrease in the overall energy consumption associated with the heating and cooling of buildings. This paper extended the analysis of the impact of using PCM, which has traditionally focused on homes of ordinary construction, to incorporate low to zero energy homes using a model of the Toronto net zero energy house developed in TRNSYS. The paper provided a description of the TRNSYS model/methodology, with reference to the wall layer used in the net zero energy house, and model of the layout of the net zero energy house in TRYNSYS. The TRYNSYS/type 204 PCM component was also presented along with the simulation results in terms of the temperature profile of the third floor of the net zero energy house on a typical winter day with varying PCM concentrations; the temperature profile of the third floor of the net zero energy house on a typical summer day with varying PCM concentrations; yearly heating/cooling load requirements of the net zero energy house for a variety of thermal mass used; temperature profile of the third floor of the net zero energy house on a typical summer day when PCM and concrete slab was used; yearly temperature profile of the third floor of the net zero energy house, illustrating the impact of using PCM; and the yearly heating/cooling load of the net zero energy house as the concentration of PCM was varied. It was concluded that the use of building integrated PCM can reduce temperature fluctuations considerably in the summer but only slightly in the winter. 16 refs., 1 tab., 8 figs.

  15. Non-von Neumann computing using plasmon particles interacting with phase change materials (Conference Presentation)

    Science.gov (United States)

    Saiki, Toshiharu

    2016-09-01

    Control of localized surface plasmon resonance (LSPR) excited on metal nanostructures has drawn attention for applications in dynamic switching of plasmonic devices. As a reversible active media for LSPR control, chalcogenide phase-change materials (PCMs) such as GeSbTe (GST) are promising for high-contrast robust plasmonic switching. Owing to the plasticity and the threshold behavior during both amorphization and crystallization of PCMs, PCM-based LSPR switching elements possess a dual functionality of memory and processing. Integration of LSPR switching elements so that they interact with each other will allow us to build non-von-Neumann computing devices. As a specific demonstration, we discuss the implementation of a cellular automata (CA) algorithm into interacting LSPR switching elements. In the model we propose, PCM cells, which can be in one of two states (amorphous and crystalline), interact with each other by being linked by a AuNR, whose LSPR peak wavelength is determined by the phase of PCM cells on the both sides. The CA program proceeds by irradiating with a light pulse train. The local rule set is defined by the temperature rise in the PCM cells induced by the LSPR of the AuNR, which is subject to the intensity and wavelength of the irradiating pulse. We also investigate the possibility of solving a problem analogous to the spin-glass problem by using a coupled dipole system, in which the individual coupling strengths can be modified to optimize the system so that the exact solution can be easily reached. For this algorithm, we propose an implementation based on an idea that coupled plasmon particles can create long-range spatial correlations, and the interaction of this with a phase-change material allows the coupling strength to be modified.

  16. Three-dimensional simulations of microstructural evolution in polycrystalline dual-phase materials with constant volume fractions

    DEFF Research Database (Denmark)

    Poulsen, Stefan Othmar; Voorhees, P.W.; Lauridsen, Erik Mejdal

    2013-01-01

    The microstructural evolution of a polycrystalline dual-phase material with a constant volume fraction of the phases was investigated using large-scale three-dimensional phase-field simulations. All materials parameters are taken to be isotropic, and microstructures with volume fractions of 50....../50 and 40/60 were examined. After an initial transient, the number of grains decrease from ∼2600 to ∼500. It was found that the mean grain size of grains of both phases obeyed a power law with an exponent of 3, and the microstructural evolution was found to be controlled by diffusion. Steady...... with the topology of single-phase grain structures as determined by experiment and simulation. The evolution of size and number of faces for the minority and majority phase grains in the 40/60 volume fraction simulation is presented and discussed. Non-constant curvature across some interphase boundaries...

  17. Effect of expanded graphite on the phase change materials of high density polyethylene/wax blends

    Energy Technology Data Exchange (ETDEWEB)

    AlMaadeed, M.A., E-mail: m.alali@qu.edu.qa [Center for Advanced Materials, Qatar University, 2713 Doha (Qatar); Labidi, Sami [Center for Advanced Materials, Qatar University, 2713 Doha (Qatar); Krupa, Igor [QAPCO Polymer Chair, Center for Advanced Materials, Qatar University, P.O. Box 2713, Doha (Qatar); Karkri, Mustapha [Université Paris-Est CERTES, 61 avenue du Général de Gaulle, 94010 Créteil (France)

    2015-01-20

    Highlights: • Expanded graphite (EG) and low melting point (42.3 °C) wax were added to HDPE to form phase change material. • EG was well dispersed in the composites and did not affect the melting or crystallization of the HDPE matrix. • EG increased the thermal stability of the composites by reducing chain mobility and inhibiting degradation. • The addition of a relatively small quantity of EG enhances the heat conduction in the composite. • HDPE/40% RT42 that contained up to 15% EG demonstrated excellent mechanical and thermal properties and can be used as PCM. - Abstract: Phase change materials fabricated from high density polyethylene (HDPE) blended with 40 or 50 wt% commercial wax (melting point of 43.08 °C) and up to 15 wt% expanded graphite (EG) were studied. Techniques including scanning electron microscope (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and an experimental device to measure diffusivity and conductivity (DICO) were used to determine the microstructural, mechanical and thermal properties of the composites. The composites possessed good mechanical properties. Additionally, no leaching was observed during material processing or characterization. Although the Young’s modulus increased with the addition of EG, no significant changes in tensile strength were detected. The maximum Young’s modulus achieved was 650 MPa for the HDPE/40% wax composite with 15 wt% EG. The EG was well dispersed within the composites and did not affect the melting or crystallization of the HDPE matrix. The incorporation of EG increased the thermal stability of the composites by reducing chain mobility and inhibiting degradation. The intensification of thermal conductivity occurred with increasing fractions of EG, which was attributed to the high thermal conductivity of graphite. The maximum quantity of heat stored by latent heat was found for the HDPE/40% wax composite with EG. The addition of a relatively small quantity

  18. Novel dynamic thermal characterization of multifunctional concretes with microencapsulated phase change materials

    Science.gov (United States)

    Pisello, Anna Laura; Fabiani, Claudia; D'Alessandro, Antonella; Cabeza, Luisa F.; Ubertini, Filippo; Cotana, Franco

    2017-04-01

    Concrete is widely applied in the construction sector for its reliable mechanical performance, its easiness of use and low costs. It also appears promising for enhancing the thermal-energy behavior of buildings thanks to its capability to be doped with multifunctional fillers. In fact, key studies acknowledged the benefits of thermally insulated concretes for applications in ceilings and walls. At the same time, thermal capacity also represents a key property to be optimized, especially for lightweight constructions. In this view, Thermal-Energy Storage (TES) systems have been recently integrated into building envelopes for increasing thermal inertia. More in detail, numerical experimental investigations showed how Phase Change materials (PCMs), as an acknowledged passive TES strategy, can be effectively included in building envelope, with promising results in terms of thermal buffer potentiality. In particular, this work builds upon previous papers aimed at developing the new PCM-filled concretes for structural applications and optimized thermalenergy efficiency, and it is focused on the development of a new experimental method for testing such composite materials in thermal-energy dynamic conditions simulated in laboratory by exposing samples to environmentally controlled microclimate while measuring thermal conductivity and diffusivity by means of transient plane source techniques. The key findings show how the new composites are able to increasingly delay the thermal wave with increasing the PCM concentration and how the thermal conductivity varies during the course of the phase change, in both melting and solidification processes. The new analysis produces useful findings in proposing an effective method for testing composite materials with adaptive thermal performance, much needed by the scientific community willing to study building envelopes dynamics.

  19. A 4-D dataset for validation of crystal growth in a complex three-phase material, ice cream

    Science.gov (United States)

    Rockett, P.; Karagadde, S.; Guo, E.; Bent, J.; Hazekamp, J.; Kingsley, M.; Vila-Comamala, J.; Lee, P. D.

    2015-06-01

    Four dimensional (4D, or 3D plus time) X-ray tomographic imaging of phase changes in materials is quickly becoming an accepted tool for quantifying the development of microstructures to both inform and validate models. However, most of the systems studied have been relatively simple binary compositions with only two phases. In this study we present a quantitative dataset of the phase evolution in a complex three-phase material, ice cream. The microstructure of ice cream is an important parameter in terms of sensorial perception, and therefore quantification and modelling of the evolution of the microstructure with time and temperature is key to understanding its fabrication and storage. The microstructure consists of three phases, air cells, ice crystals, and unfrozen matrix. We perform in situ synchrotron X-ray imaging of ice cream samples using in-line phase contrast tomography, housed within a purpose built cold-stage (-40 to +20oC) with finely controlled variation in specimen temperature. The size and distribution of ice crystals and air cells during programmed temperature cycling are determined using 3D quantification. The microstructural evolution of three-phase materials has many other important applications ranging from biological to structural and functional material, hence this dataset can act as a validation case for numerical investigations on faceted and non-faceted crystal growth in a range of materials.

  20. Mineralogical composition and phase-to-phase relationships in natural hydraulic lime and/or natural cement - raw materials and burnt products revealed by scanning electron microscopy

    Science.gov (United States)

    Kozlovcev, Petr; Přikryl, Richard; Racek, Martin; Přikrylová, Jiřina

    2016-04-01

    In contrast to modern process of production of cement clinker, traditional burning of natural hydraulic lime below sintering temperature relied on the formation of new phases from ion migration between neighbouring mineral grains composing raw material. The importance of the mineralogical composition and spatial distribution of rock-forming minerals in impure limestones used as a raw material for natural hydraulic lime presents not well explored issue in the scientific literature. To fill this gap, the recent study focuses in detailed analysis of experimentally burnt impure limestones (mostly from Barrandian area, Bohemian Massif). The phase changes were documented by optical microscopy, X-ray diffraction, and scanning electron microscopy with an energy dispersive spectrometer (SEM-EDS) coupled with x-ray elemental mapping. The latest allowed for visualization of distribution of elements within raw materials and burnt products. SEM/EDS study brought valuable data on the presence of transitional and/or minor phases, which were poorly detectable by other methods.