Effects of grasp compatibility on long-term memory for objects.

PubMed

Canits, Ivonne; Pecher, Diane; Zeelenberg, René

2018-01-01

Previous studies have shown action potentiation during conceptual processing of manipulable objects. In four experiments, we investigated whether these motor actions also play a role in long-term memory. Participants categorized objects that afforded either a power grasp or a precision grasp as natural or artifact by grasping cylinders with either a power grasp or a precision grasp. In all experiments, responses were faster when the affordance of the object was compatible with the type of grasp response. However, subsequent free recall and recognition memory tasks revealed no better memory for object pictures and object names for which the grasp affordance was compatible with the grasp response. The present results therefore do not support the hypothesis that motor actions play a role in long-term memory. Copyright © 2017 Elsevier B.V. All rights reserved.

Non-aqueous cleaning solvent substitution

NASA Technical Reports Server (NTRS)

Meier, Gerald J.

1994-01-01

A variety of environmental, safety, and health concerns exist over use of chlorinated and fluorinated cleaning solvents. Sandia National Laboratories, Lawrence Livermore National Laboratories, and the Kansas City Division of AlliedSignal have combined efforts to focus on finding alternative cleaning solvents and processes which are effective, environmentally safe, and compliant with local, state, and federal regulations. An alternative solvent has been identified, qualified, and implemented into production of complex electronic assemblies, where aqueous and semi-aqueous cleaning processes are not allowed. Extensive compatibility studies were performed with components, piece-parts, and materials. Electrical testing and accelerated aging were used to screen for detrimental, long-term effects. A terpene, d-limonene, was selected as the solvent of choice, and it was found to be compatible with the components and materials tested. A brief history of the overall project will be presented, along with representative cleaning efficiency results, compatibility results, and residual solvent data. The electronics industry is constantly searching for proven methods and environmentally-safe materials to use in manufacturing processes. The information in this presentation will provide another option to consider on future projects for applications requiring high levels of quality, reliability, and cleanliness from non-aqueous cleaning processes.

Evaluation and Validation of Organic Materials for Advanced Stirling Convertors (ASCs): Overview

NASA Technical Reports Server (NTRS)

Shin, Euy-Sik Eugene

2015-01-01

Various organic materials are used as essential parts in Stirling Convertors for their unique properties and functionalities such as bonding, potting, sealing, thread locking, insulation, and lubrication. More efficient Advanced Stirling Convertors (ASC) are being developed for future space applications especially with a long mission cycle, sometimes up to 17 years, such as deep space exploration or lunar surface power or Mars rovers, and others. Thus, performance, durability, and reliability of those organics should be critically evaluated in every possible material-process-fabrication-service environment relations based on their mission specifications. In general, thermal stability, radiation hardness, outgassing, and material compatibility of the selected organics have been systematically evaluated while their process and fabrication conditions and procedures were being optimized. Service environment-simulated long term aging tests up to 4 years were performed as a function of temperature for durability assessment of the most critical organic material systems.

Dye Sensitized Solar Cells for Economically Viable Photovoltaic Systems.

PubMed

Jung, Hyun Suk; Lee, Jung-Kun

2013-05-16

TiO2 nanoparticle-based dye sensitized solar cells (DSSCs) have attracted a significant level of scientific and technological interest for their potential as economically viable photovoltaic devices. While DSSCs have multiple benefits such as material abundance, a short energy payback period, constant power output, and compatibility with flexible applications, there are still several challenges that hold back large scale commercialization. Critical factors determining the future of DSSCs involve energy conversion efficiency, long-term stability, and production cost. Continuous advancement of their long-term stability suggests that state-of-the-art DSSCs will operate for over 20 years without a significant decrease in performance. Nevertheless, key questions remain in regards to energy conversion efficiency improvements and material cost reduction. In this Perspective, the present state of the field and the ongoing efforts to address the requirements of DSSCs are summarized with views on the future of DSSCs.

The Effects of Long Term Cure on Offgassed Products of Coatings

NASA Technical Reports Server (NTRS)

Engle, Ginger; Whitfield, Steve

1997-01-01

The Environmental Chemistry and Compatability Team at The Marshall Space Flight Center conducts toxic offgassing analysis on materials and flight hardware for use in habitable environments aboard the Space Shuttle and the International Space Station. As part of Research and Development, the Toxic Offgassing Laboratory conducted a long term cure study on four polyurethane coatings which are slated for potential use on Space Station. This study demonstrates the effects of cure time and temperature on the total tox value (sum T) and the maximum usage weight for each coating. All analysis was conducted according to test procedures outlined specifically for Space Station environments. Therefore, the ratings and weight limits generated for these materials are most applicable to space environments. However, this test does give some indication of time frames for solvent removal and is therefore of interest to, the environmental community as a whole.

Long term corrosion on T91 and AISI1 316L steel in flowing lead alloy and corrosion protection barrier development: Experiments and models

NASA Astrophysics Data System (ADS)

Weisenburger, A.; Schroer, C.; Jianu, A.; Heinzel, A.; Konys, J.; Steiner, H.; Müller, G.; Fazio, C.; Gessi, A.; Babayan, S.; Kobzova, A.; Martinelli, L.; Ginestar, K.; Balbaud-Célerier, F.; Martín-Muñoz, F. J.; Soler Crespo, L.

2011-08-01

Considering the status of knowledge on corrosion and corrosion protection and especially the need for long term compatibility data of structural materials in HLM a set of experiments to generate reliable long term data was defined and performed. The long term corrosion behaviour of the two structural materials foreseen in ADS, 316L and T91, was investigated in the design relevant temperature field, i.e. from 300 to 550 °C. The operational window of the two steels in this temperature range was identified and all oxidation data were used to develop and validate the models of oxide scale growth in PbBi. A mechanistic model capable to predict the oxidation rate applying some experimentally fitted parameters has been developed. This model assumes parabolic oxidation and might be used for design and safety relevant investigations in future. Studies on corrosion barrier development allowed to define the required Al content for the formation of thin alumina scales in LBE. These results as well as future steps and required improvements are discussed. Variation of experimental conditions clearly showed that specific care has to be taken with respect to local flow conditions and oxygen concentrations.

500 C Electronic Packaging and Dielectric Materials for High Temperature Applications

NASA Technical Reports Server (NTRS)

Chen, Liang-yu; Neudeck, Philip G.; Spry, David J.; Beheim, Glenn M.; Hunter, Gary W.

2016-01-01

High-temperature environment operable sensors and electronics are required for exploring the inner solar planets and distributed control of next generation aeronautical engines. Various silicon carbide (SiC) high temperature sensors, actuators, and electronics have been demonstrated at and above 500C. A compatible packaging system is essential for long-term testing and application of high temperature electronics and sensors. High temperature passive components are also necessary for high temperature electronic systems. This talk will discuss ceramic packaging systems developed for high temperature electronics, and related testing results of SiC circuits at 500C and silicon-on-insulator (SOI) integrated circuits at temperatures beyond commercial limit facilitated by these high temperature packaging technologies. Dielectric materials for high temperature multilayers capacitors will also be discussed. High-temperature environment operable sensors and electronics are required for probing the inner solar planets and distributed control of next generation aeronautical engines. Various silicon carbide (SiC) high temperature sensors, actuators, and electronics have been demonstrated at and above 500C. A compatible packaging system is essential for long-term testing and eventual applications of high temperature electronics and sensors. High temperature passive components are also necessary for high temperature electronic systems. This talk will discuss ceramic packaging systems developed for high electronics and related testing results of SiC circuits at 500C and silicon-on-insulator (SOI) integrated circuits at temperatures beyond commercial limit facilitated by high temperature packaging technologies. Dielectric materials for high temperature multilayers capacitors will also be discussed.

Aluminum-Scandium Alloys: Material Characterization, Friction Stir Welding, and Compatibility With Hydrogen Peroxide (MSFC Center Director's Discretionary Fund Final Report, Proj. No. 04-14)

NASA Technical Reports Server (NTRS)

Lee, J. A.; Chen, P. S.

2004-01-01

This Technical Memorandum describes the development of several high-strength aluminum (Al) alloys that are compatible with hydrogen peroxide (H2O2) propellant for NASA Hypersonic-X (Hyper-X) vehicles fuel tanks and structures. The yield strengths for some of these Al-magnesium-based alloys are more than 3 times stronger than the conventional 5254-H112 Al alloy, while maintaining excellent H2O2 compatibility similar to class 1 5254 alloy. The alloy development strategy is to add scandium, zirconium, and other transitional metals with unique electrochemical properties, which will not act as catalysts, to decompose the highly concentrated 90 percent H2O2. Test coupons are machined from sheet metals for H2O2 long-term exposure testing and mechanical properties testing. In addition, the ability to weld the new alloys using friction stir welding has also been explored. The new high-strength alloys could represent an enabling material technology for Hyper-X vehicles, where flight weight reduction is a critical requirement.

The Catastrophe Revisited

PubMed Central

Ratner, Buddy D.

2007-01-01

The biomaterials community has been unable to accurately assign the term “blood compatible” to a biomaterial in spite of 50 years of intensive research on the subject. There is no clear consensus as to which materials are “blood compatible.” There are no standardized methods to assess blood compatibility. Since we use millions of devices in contact with blood each year, it is imperative we give serious thought to this intellectual catastrophe. In this perspective, I consider five hypotheses as to why progress has been slow in evolving a clear understanding of blood compatibility: Hypothesis 1 -- It is impossible to make a blood compatible material. Hypothesis 2 -- We do not understand the biology behind blood compatibility. Hypothesis 3 -- We do not understand how to test for or evaluate blood compatibility. Hypothesis 4 -- Certain materials of natural origin seem to show better blood compatibility but we do not know how to exploit this concept. Hypothesis 5 -- We now have better blood compatible materials but the regulatory and economic climate prevent adoption in clinical practice. PMID:17689608

The design and fabrication of a prototype trash compacting unit. [for long duration space missions

NASA Technical Reports Server (NTRS)

1973-01-01

A prototype trash compactor, that is compatible with the anticipated requirements of future long-term space missions, is described. Preliminary problem definition studies were conducted to identify typical types and quantities of waste materials to be expected from a typical mission. Bench-scale compaction tests were then conducted on typical waste materials to determine force/compaction curves. These data were used to design a boilerplate compactor that was fabricated to prove the feasibility of the basic design concept. A final design was then prepared from which the deliverable unit was fabricated. Design concepts are presented for suggested further development of the compactor, including a version that is capable of handling wet biodegradable wastes.

Development of a Self-Assessment Tool to Facilitate Decision-Making in Choosing a Long Term Care Administration Major

ERIC Educational Resources Information Center

Johs-Artisensi, Jennifer L.; Olson, Douglas M.; Nahm, Abraham Y.

2016-01-01

Long term care administrators need a broad base of knowledge, skills, and interests to provide leadership and be successful in managing a fiscally responsible, quality long term care organization. Researchers developed a tool to help students assess whether a long term care administration major is a compatible fit. With input from professionals in…

Thermal Control Working Group report

NASA Technical Reports Server (NTRS)

Haslett, Robert; Mahefkey, E. Thomas

1986-01-01

The Thermal Control Working Group limited its evaluation to issues associated with Earth orbiting and planetary spacecraft with power levels up to 50 kW. It was concluded that the space station technology is a necessary precursor but does not meet S/C 2000 needs (life, high heat flux, long term cryogenics, and survivability). Additional basic and applied research are required (fluid/materials compatibility and two phase system modeling). Scaling, the key issue, must define accelerated life test criteria. The two phase systems require 0g to 1 g correlation. Additional ground test beds are required and combined space environment tests of materials.

Space thermal control development

NASA Technical Reports Server (NTRS)

Hoover, M. J.; Grodzka, P. G.; Oneill, M. J.

1971-01-01

The results of experimental investigations on a number of various phase change materials (PCMs) and PCMs in combination with metals and other materials are reported. The evaluations include the following PCM system performance characteristics: PCM and PCM/filler thermal diffusivities, the effects of long-term thermal cycling, PCM-container compatibility, and catalyst effectiveness and stability. Three PCMs demonstrated performance acceptable enough to be considered for use in prototype aluminum thermal control devices. These three PCMs are lithium nitrate trihydrate with zinc hydroxy nitrate catalyst, acetamide, and myristic acid. Of the fillers tested, aluminum honeycomb filler was found to offer the most increase in system thermal diffusivity.

Material Compatibility with Space Storable Propellants. Design Guidebook

NASA Technical Reports Server (NTRS)

Uney, P. E.; Fester, D. A.

1972-01-01

An important consideration in the design of spacecraft for interplanetary missions is the compatibility of storage materials with the propellants. Serious problems can arise because many propellants are either extremely reactive or subject to catalytic decomposition, making the selection of proper materials of construction for propellant containment and control a critical requirement for the long-life applications. To aid in selecting materials and designing and evaluating various propulsion subsystems, available information on the compatibility of spacecraft materials with propellants of interest was compiled from literature searches and personal contacts. The compatibility of both metals and nonmetals with hydrazine, monomethyl hydrazine, nitrated hydrazine, and diborance fuels and nitrogen tetroxide, fluorine, oxygen difluoride, and Flox oxidizers was surveyed. These fuels and oxidizers encompass the wide variety of problems encountered in propellant storage. As such, they present worst case situations of the propellant affecting the material and the material affecting the propellant. This includes material attack, propellant decomposition, and the formation of clogging materials.

A Systems Approach to Developing an Affordable Space Ground Transportation Architecture using a Commonality Approach

NASA Technical Reports Server (NTRS)

Garcia, Jerry L.; McCleskey, Carey M.; Bollo, Timothy R.; Rhodes, Russel E.; Robinson, John W.

2012-01-01

This paper presents a structured approach for achieving a compatible Ground System (GS) and Flight System (FS) architecture that is affordable, productive and sustainable. This paper is an extension of the paper titled "Approach to an Affordable and Productive Space Transportation System" by McCleskey et al. This paper integrates systems engineering concepts and operationally efficient propulsion system concepts into a structured framework for achieving GS and FS compatibility in the mid-term and long-term time frames. It also presents a functional and quantitative relationship for assessing system compatibility called the Architecture Complexity Index (ACI). This paper: (1) focuses on systems engineering fundamentals as it applies to improving GS and FS compatibility; (2) establishes mid-term and long-term spaceport goals; (3) presents an overview of transitioning a spaceport to an airport model; (4) establishes a framework for defining a ground system architecture; (5) presents the ACI concept; (6) demonstrates the approach by presenting a comparison of different GS architectures; and (7) presents a discussion on the benefits of using this approach with a focus on commonality.

Electrochemical, Polarization, and Crevice Corrosion Testing of Nitinol 60, A Supplement to the ECLSS Sustaining Materials Compatibility Study

NASA Technical Reports Server (NTRS)

Lee, R. E.

2016-01-01

In earlier trials, electrochemical test results were presented for six noble metals evaluated in test solutions representative of waste liquids processed in the Environmental Control and Life Support System (ECLSS) aboard the International Space Station (ISS). Subsequently, a seventh metal, Nitinol 60, was added for evaluation and subjected to the same test routines, data analysis, and theoretical methodologies. The previous six test metals included three titanium grades, (commercially pure, 6Al-4V alloy and 6Al-4V low interstitial alloy), two nickel-chromium alloys (Inconel(RegisteredTrademark) 625 and Hastelloy(RegisteredTrademark) C276), and one high-tier stainless steel (Cronidur(RegisteredTrademark) 30). The three titanium alloys gave the best results of all the metals, indicating superior corrosive nobility and galvanic protection properties. For this current effort, the results have clearly shown that Nitinol 60 is almost as noble as titanium, being very corrosion-resistant and galvanically compatible with the other six metals electrochemically and during long-term exposure. is also quite noble as it is very corrosion resistant and galvanically compatible with the other six metals from both an electrochemical perspective and long-term crevice corrosion scenario. This was clearly demonstrated utilizing the same techniques for linear, Tafel and cyclic polarization, and galvanic coupling of the metal candidate as was done for the previous study. The high nobility and low corrosion susceptibility for Nitinol 60 appear to be intermediate to the nickel/chromium alloys and the titanium metals with indications that are more reflective of the titanium metals in terms of general corrosion and pitting behavior.

Pt and Pd catalyzed oxidation of Li 2O 2 and DMSO during Li–O 2 battery charging

DOE PAGES

Gittleson, Forrest S.; Ryu, Won-Hee; Schwab, Mark; ...

2016-01-01

Rechargeable Li-O 2 and Li-air batteries require electrode and electrolyte materials that synergistcally promote long-term cell operation. We investigate the role of noble metals Pt and Pd as catalysts for the Li-O 2 oxidation process and their compatibility with a dimethyl sulfoxide (DMSO) based electrolyte. Lastly, we identify a basis for low potential Li 2O 2 evolution followed by oxidative decomposition of the electrolyte to form carbonate side products.

Design and preparation of novel polyarylene ether materials based on Diels-Alder reaction as the crosslinker for electrooptical modulators

NASA Astrophysics Data System (ADS)

Gao, Wu; Hou, Wenjun; Zhen, Zhen; Liu, Xinhou; Liu, Jialei; Fedorchuk, A. A.; Czaja, P.

2016-07-01

Novel crosslinkable organic linear electro-optical (EO) material based on polyarylene ether as the main chain host polymer was designed and prepared. The host polymer with rigid aromatic has demonstrated a good compatibility with the guest chromophore. Long side chain with anthracene ensured the crosslinkable reaction and appropriate glass transition temperature of the host polymer (55 °C). The EO r33 tensor coefficient for this novel EO material has been magnitude of 66 pm/V at 1310 nm and the excellent long term stability at 85 °C. These parameters permit to consider their application in fabrication of organic electro optical devices. The semi-empirical and DFT quantum chemical simulations were performed for 4 principal chromophores to clarify a role of cross-linker in the enhancement of the ground state dipole moments and effective hyperpolarizabilities.

An Overview of Long Duration Sodium Heat Pipe Tests

NASA Astrophysics Data System (ADS)

Rosenfeld, John H.; Ernst, Donald M.; Lindemuth, James E.; Sanzi, James L.; Geng, Steven M.; Zuo, Jon

2004-02-01

High temperature heat pipes are being evaluated for use in energy conversion applications such as fuel cells, gas turbine re-combustors, and Stirling cycle heat sources; with the resurgence of space nuclear power, additional applications include reactor heat removal elements and radiator elements. Long operating life and reliable performance are critical requirements for these applications. Accordingly long-term materials compatibility is being evaluated through the use of high temperature life test heat pipes. Thermacore, Inc. has carried out several sodium heat pipe life tests to establish long term operating reliability. Four sodium heat pipes have recently demonstrated favorable materials compatibility and heat transport characteristics at high operating temperatures in air over long time periods. A 316L stainless steel heat pipe with a sintered porous nickel wick structure and an integral brazed cartridge heater has successfully operated at 650C to 700C for over 115,000 hours without signs of failure. A second 316L stainless steel heat pipe with a specially-designed Inconel 601 rupture disk and a sintered nickel powder wick has demonstrated over 83,000 hours at 600C to 650C with similar success. A representative one-tenth segment Stirling Space Power Converter heat pipe with an Inconel 718 envelope and a stainless steel screen wick has operated for over 41,000 hours at nearly 700C. A hybrid (i.e. gas-fired and solar) heat pipe with a Haynes 230 envelope and a sintered porous nickel wick structure was operated for about 20,000 hours at nearly 700C without signs of degradation. These life test results collectively have demonstrated the potential for high temperature heat pipes to serve as reliable energy conversion system components for power applications that require long operating lifetime with high reliability. Detailed design specifications, operating history, and test results are described for each of these sodium heat pipes. Lessons learned and future life test plans are also discussed.

An Overview of Long Duration Sodium Heat Pipe Tests

NASA Technical Reports Server (NTRS)

Rosenfeld, John H.; Ernst, Donald M.; Lindemuth, James E.; Sanzi, James L.; Geng, Steven M.; Zuo, Jon

2004-01-01

High temperature heat pipes are being evaluated for use in energy conversion applications such as fuel cells, gas turbine re-combustors, and Stirling cycle heat sources; with the resurgence of space nuclear power, additional applications include reactor heat removal elements and radiator elements. Long operating life and reliable performance are critical requirements for these applications. Accordingly long-term materials compatibility is being evaluated through the use of high temperature life test heat pipes. Thermacore International, Inc., has carried out several sodium heat pipe life tests to establish long term operating reliability. Four sodium heat pipes have recently demonstrated favorable materials compatibility and heat transport characteristics at high operating temperatures in air over long time periods. A 3l6L stainless steel heat pipe with a sintered porous nickel wick structure and an integral brazed cartridge heater has successfully operated at 650 to 700 C for over 115,000 hours without signs of failure. A second 3l6L stainless steel heat pipe with a specially-designed Inconel 60 I rupture disk and a sintered nickel powder wick has demonstrated over 83,000 hours at 600 to 650 C with similar success. A representative one-tenth segment Stirling Space Power Converter heat pipe with an Inconel 718 envelope and a stainless steel screen wick has operated for over 41 ,000 hours at nearly 700 0c. A hybrid (i.e. gas-fired and solar) heat pipe with a Haynes 230 envelope and a sintered porous nickel wick structure was operated for about 20,000 hours at nearly 700 C without signs of degradation. These life test results collectively have demonstrated the potential for high temperature heat pipes to serve as reliable energy conversion system components for power applications that require long operating lifetime with high reliability, Detailed design specifications, operating hi story, and test results are described for each of these sodium heat pipes. Lessons learned and future life test plans are also discussed.

Demonstration of Synaptic Behaviors and Resistive Switching Characterizations by Proton Exchange Reactions in Silicon Oxide

PubMed Central

Chang, Yao-Feng; Fowler, Burt; Chen, Ying-Chen; Zhou, Fei; Pan, Chih-Hung; Chang, Ting-Chang; Lee, Jack C.

2016-01-01

We realize a device with biological synaptic behaviors by integrating silicon oxide (SiOx) resistive switching memory with Si diodes. Minimal synaptic power consumption due to sneak-path current is achieved and the capability for spike-induced synaptic behaviors is demonstrated, representing critical milestones for the use of SiO2–based materials in future neuromorphic computing applications. Biological synaptic behaviors such as long-term potentiation (LTP), long-term depression (LTD) and spike-timing dependent plasticity (STDP) are demonstrated systematically using a comprehensive analysis of spike-induced waveforms, and represent interesting potential applications for SiOx-based resistive switching materials. The resistive switching SET transition is modeled as hydrogen (proton) release from (SiH)2 to generate the hydrogen bridge defect, and the RESET transition is modeled as an electrochemical reaction (proton capture) that re-forms (SiH)2. The experimental results suggest a simple, robust approach to realize programmable neuromorphic chips compatible with large-scale CMOS manufacturing technology. PMID:26880381

Demonstration of Synaptic Behaviors and Resistive Switching Characterizations by Proton Exchange Reactions in Silicon Oxide

NASA Astrophysics Data System (ADS)

Chang, Yao-Feng; Fowler, Burt; Chen, Ying-Chen; Zhou, Fei; Pan, Chih-Hung; Chang, Ting-Chang; Lee, Jack C.

2016-02-01

We realize a device with biological synaptic behaviors by integrating silicon oxide (SiOx) resistive switching memory with Si diodes. Minimal synaptic power consumption due to sneak-path current is achieved and the capability for spike-induced synaptic behaviors is demonstrated, representing critical milestones for the use of SiO2-based materials in future neuromorphic computing applications. Biological synaptic behaviors such as long-term potentiation (LTP), long-term depression (LTD) and spike-timing dependent plasticity (STDP) are demonstrated systematically using a comprehensive analysis of spike-induced waveforms, and represent interesting potential applications for SiOx-based resistive switching materials. The resistive switching SET transition is modeled as hydrogen (proton) release from (SiH)2 to generate the hydrogen bridge defect, and the RESET transition is modeled as an electrochemical reaction (proton capture) that re-forms (SiH)2. The experimental results suggest a simple, robust approach to realize programmable neuromorphic chips compatible with large-scale CMOS manufacturing technology.

A synaptic device built in one diode-one resistor (1D-1R) architecture with intrinsic SiOx-based resistive switching memory

NASA Astrophysics Data System (ADS)

Chang, Yao-Feng; Fowler, Burt; Chen, Ying-Chen; Zhou, Fei; Pan, Chih-Hung; Chang, Kuan-Chang; Tsai, Tsung-Ming; Chang, Ting-Chang; Sze, Simon M.; Lee, Jack C.

2016-04-01

We realize a device with biological synaptic behaviors by integrating silicon oxide (SiOx) resistive switching memory with Si diodes to further minimize total synaptic power consumption due to sneak-path currents and demonstrate the capability for spike-induced synaptic behaviors, representing critical milestones for the use of SiO2-based materials in future neuromorphic computing applications. Biological synaptic behaviors such as long-term potentiation, long-term depression, and spike-timing dependent plasticity are demonstrated systemically with comprehensive investigation of spike waveform analyses and represent a potential application for SiOx-based resistive switching materials. The resistive switching SET transition is modeled as hydrogen (proton) release from the (SiH)2 defect to generate the hydrogenbridge defect, and the RESET transition is modeled as an electrochemical reaction (proton capture) that re-forms (SiH)2. The experimental results suggest a simple, robust approach to realize programmable neuromorphic chips compatible with largescale complementary metal-oxide semiconductor manufacturing technology.

Development of advanced fuel cell system, phase 2

NASA Technical Reports Server (NTRS)

Handley, L. M.; Meyer, A. P.; Bell, W. F.

1973-01-01

A multiple task research and development program was performed to improve the weight, life, and performance characteristics of hydrogen-oxygen alkaline fuel cells for advanced power systems. Development and characterization of a very stable gold alloy catalyst was continued from Phase I of the program. A polymer material for fabrication of cell structural components was identified and its long term compatibility with the fuel cell environment was demonstrated in cell tests. Full scale partial cell stacks, with advanced design closed cycle evaporative coolers, were tested. The characteristics demonstrated in these tests verified the feasibility of developing the engineering model system concept into an advanced lightweight long life powerplant.

Design and development of microbioreactors for long-term cell culture in controlled oxygen microenvironments.

PubMed

Abaci, Hasan E; Devendra, Raghavendra; Smith, Quinton; Gerecht, Sharon; Drazer, German

2012-02-01

The ability to control the oxygen level to which cells are exposed in tissue culture experiments is crucial for many applications. Here, we design, develop and test a microbioreactor (MBR) for long-term cell culture studies with the capability to accurately control and continuously monitor the dissolved oxygen (DO) level in the cell microenvironment. In addition, the DO level can be controlled independently from other cues, such as the viscous shear-stress acting on the cells. We first analyze the transport of oxygen in the proposed device and determine the materials and dimensions that are compatible with uniform oxygen tension and low shear-stress at the cell level. The device is also designed to culture a statistically significant number of cells. We use fully transparent materials and the overall design of the device is compatible with live-cell imaging. The proposed system includes real-time read-out of actual DO levels, is simple to fabricate at low cost, and can be easily expanded to control the concentration of other microenvironmental solutes. We performed control experiments in the absence of cells to demonstrate that the MBR can be used to accurately modulate DO levels ranging from atmospheric level to 1%, both under no flow and perfusion conditions. We also demonstrate cancer cell attachment and viability within the MBR. The proposed MBR offers the unprecedented capability to perform on-line measurement and analysis of DO levels in the microenvironment of adherent cultures and to correlate them with various cellular responses.

Dissociative adsorption of environment-friendly insulating medium C3F7CN on Cu(111) and Al(111) surface: A theoretical evaluation

NASA Astrophysics Data System (ADS)

Zhang, Xiaoxing; Li, Yi; Chen, Dachang; Xiao, Song; Tian, Shuangshuang; Tang, Ju; Wang, Dibo

2018-03-01

SF6 is extensively used in electrical applications because of its excellent insulation and arc extinguishing performance, but its strong greenhouse effect has negative impact on the atmosphere. The excellent performance of C3F7CN in greenhouse effect, insulation ability, safety, and thermal stability has been demonstrated, indicating that this compound can replace SF6 in electrical applications. However, little information is available on the compatibility of C3F7CN with metals, such as copper and aluminum, in devices. Material compatibility between new gas mixtures and materials used in Gas Insulated Switchgear (GIS) should be investigated to determine the long-term behavior of materials. In this paper, dissociative adsorption of C3F7CN on Cu (1 1 1) and Al (1 1 1) surfaces were analyzed based on density functional theory. Adsorption energy, charge transfer, density of states, and electron density difference of interaction between C3F7CN and two metals were analyzed. It was found that the adsorption energy of C3F7CN adsorbed on Cu (1 1 1) and Al (1 1 1) is both below 0.8 eV. This value indicates that the interaction between them is not very strong. In addition, the dissociation reaction path of gas molecules after adsorption requires certain activation energy. Therefore, C3F7CN and copper or aluminum have certain compatibility and the compatibility of C3F7CN with aluminum is better than that of copper. Related results provide a reference for predicting the aging mechanism of equipment and the selection or modification of major materials for equipment.

Stability of Gadolinium-Doped Liquid Organic Scintillators

NASA Astrophysics Data System (ADS)

Gromov, M. B.; Kuznetsov, D. S.; Murchenko, A. E.; Novikova, G. Ya.; Obinyakov, B. A.; Oralbaev, A. Yu.; Plakitina, K. V.; Skorokhvatov, M. D.; Sukhotin, S. V.; Chepurnov, A. S.; Etenko, A. V.

2018-03-01

The technology of preparing a linear-alkylbenzene-based gadolinium-doped liquid organic scintillator (Gd-LOS) as a target material in reactor antineutrino detectors has been developed. Results of longterm measurements of the light yield of Gd-LOS in contact with acryl and stainless steel are presented, which confirm the compatibility of Gd-LOS with these materials. The measurements were performed for two otherwise identical LOS detectors only differing in wall materials of the sensitive volume: acryl versus stainless steel. The results of measurements over about one year showed almost the same, relatively small decreases in the light yield of both detectors. It is concluded that both structural materials can be used in detector parts contacting with Gd-doped scintillator. Such a long-term parallel comparative test was carried out for the first time.

Opportunities and challenges for the biodegradable magnesium alloys as next-generation biomaterials

PubMed Central

Ding, Wenjiang

2016-01-01

In recent years, biodegradable magnesium alloys emerge as a new class of biomaterials for tissue engineering and medical devices. Deploying biodegradable magnesium-based materials not only avoids a second surgical intervention for implant removal but also circumvents the long-term foreign body effect of permanent implants. However, these materials are often subjected to an uncontrolled and fast degradation, acute toxic responses and rapid structural failure presumably due to a localized, too rapid corrosion process. The patented Mg–Nd–Zn–based alloys (JiaoDa BioMg [JDBM]) have been developed in Shanghai Jiao Tong University in recent years. The alloy series exhibit lower biodegradation rate and homogeneous nanophasic degradation patterns as compared with other biodegradable Mg alloys. The in vitro cytotoxicity tests using various types of cells indicate excellent biocompatibility of JDBM. Finally, bone implants using JDBM-1 alloy and cardiovascular stents using JDBM-2 alloy have been successfully fabricated and in vivo long-term assessment via implantation in animal model have been performed. The results confirmed the reduced degradation rate in vivo, excellent tissue compatibility and long-term structural and mechanical durability. Thus, this novel Mg-alloy series with highly uniform nanophasic biodegradation represent a major breakthrough in the field and a promising candidate for manufacturing the next generation biodegradable implants. PMID:27047673

Problems in the long-term storage of data obtained from scientific space experiments

NASA Technical Reports Server (NTRS)

Zlotin, G. N.; Khovanskiy, Y. D.

1975-01-01

It is shown that long-term data storage systems can be achieved when the system which organizes and conducts the scientific space experiments is equipped with a specialized subsystem: the information filing system. Its main functions are described along with the necessity of stage-by-stage development and compatibility with the data processing systems. The requirements for long-term data storage media are discussed.

Properties of indirect composites reinforced with monomer-impregnated glass fiber.

PubMed

Tanoue, Naomi; Sawase, Takashi; Matsumura, Hideo; McCabe, John F

2012-07-01

Sufficient flexural strength is required for long-term clinical use of fixed partial dentures made with fiber-reinforced composite. The flexural strengths of indirect composite materials reinforced with a monomer-preimpregnated glass fiber material were determined to evaluate the compatibility of the composites to glass fiber material. Four types (microhybrid, nanohybrid, microfilled, and minifilled) of indirect composites and a unidirectional long glass fiber material were selected for investigation. The composites were placed on a fiber plate and polymerized in accordance with the respective manufacturer's instructions. Rectangular bar fiber-composite specimens were machined and the flexural strength was calculated. The flexural strength of each indirect composite was also measured. The microfilled composite with the lowest filler content (70 wt%) exhibited the highest increase ratio using the fiber, although its strength without fiber reinforcement was the lowest (62.1 MPa). The fiber-microhybrid specimen demonstrated the highest mean strength (355.9 MPa), although the filler content of the microhybrid composite was comparatively low (73 wt%). The type of composite material should be considered for the selection of an optimal fiber-composite combination.

Hydrocarbon-fuel/combustion-chamber-liner materials compatibility

NASA Technical Reports Server (NTRS)

Gage, Mark L.

1990-01-01

Results of material compatibility experiments using hydrocarbon fuels in contact with copper-based combustion chamber liner materials are presented. Mil-Spec RP-1, n- dodecane, propane, and methane fuels were tested in contact with OFHC, NASA-Z, and ZrCu coppers. Two distinct test methods were employed. Static tests, in which copper coupons were exposed to fuel for long durations at constant temperature and pressure, provided compatibility data in a precisely controlled environment. Dynamic tests, using the Aerojet Carbothermal Test Facility, provided fuel and copper compatibility data under realistic booster engine service conditions. Tests were conducted using very pure grades of each fuel and fuels to which a contaminant, e.g., ethylene or methyl mercaptan, was added to define the role played by fuel impurities. Conclusions are reached as to degradation mechanisms and effects, methods for the elimination of these mechanisms, selection of copper alloy combustion chamber liners, and hydrocarbon fuel purchase specifications.

Titania nanotube arrays as interfaces for blood-contacting implantable devices: a study evaluating the nanotopography-associated activation and expression of blood plasma components.

PubMed

Smith, Barbara S; Popat, Ketul C

2012-08-01

The constant exposure of implantable biomaterials such as titanium and titanium alloys to blood-introducesserious and ongoing concerns regarding poor blood-material interactions. To date, all blood-contacting materials have been shown to initiate immunological events in the form of inflammation, thrombosis, fibrosis and infection; potentially leading to complete implant failure. Material surfaces that provide biomimetic cues such as nanoscale architectures have been shown to elicit improved cellular interaction; and thus, may provide possible solutions for enhancing blood-compatibility. However, limited information exists about the thrombogenicityof nanoscalesurface architectures. In this study, we have evaluated the efficacy of titania nanotube arrays as interfaces for blood contacting devices by investigating the thrombogenic effects using whole blood plasma. Thus, platelet/leukocyte adhesion, activation and interaction, morphology, complement activation, contact activation, platelet release reaction, fibrinogen expression and material cytotoxicity were evaluated to determine the in vitro thrombogenicity. The results presented here indicate a decrease in thrombogenic effects of titania nanotube arrays as compared to biomedical grade titanium after 2 hours of contact with whole blood plasma. This work shows the improved blood-compatibility of titania nanotube arrays, identifying this specific nanoarchitecture as a potentially optimal interface for promoting the long-term success of blood contacting biomaterials.

Candidate Materials Evaluated for a High-Temperature Stirling Convertor Heater Head

NASA Technical Reports Server (NTRS)

Bowman, Randy R.; Ritzert, Frank J.

2005-01-01

The Department of Energy and NASA have identified Stirling Radioisotope Generators (SRGs) as a candidate power system for use on long-duration, deep-space science missions and Mars rovers. One of the developments planned for an upgraded version of the current SRG design is to achieve higher efficiency by increasing the overall operating temperature of the system. Currently, the SRG operates with a heater head temperature of 650 C and is fabricated from the nickel-base superalloy 718. The current operating temperature is at the limit of alloy 718 s capability, and any planned increase in temperature will be contingent on identifying a more capable material from which to fabricate the heater head. To this end, personnel at the NASA Glenn Research Center are evaluating advanced materials for a high-temperature heater head to allow a higher convertor temperature ratio and, thus, increase the system efficiency. A generic list of properties that were used to screen the candidate materials follows: (1) creep, (2) fabricability, (3) helium gas containment, (4) long-term stability and compatibility, (5) ability to form a hermetical closeout seal, and (6) ductility and toughness.

Meta-Cresol Purple Reference Material® (RM) for Seawater pH Measurements

NASA Astrophysics Data System (ADS)

Easley, R. A.; Waters, J. F.; Place, B. J.; Pratt, K. W.

2016-02-01

The pH of seawater is a fundamental quantity that governs the carbon dioxide - carbonate system in the world's oceans. High quality pH measurements for long-term monitoring, shipboard studies, and shorter-term biological studies (mesocosm and field experiments) can be ensured through a reference material (RM) that is compatible with existing procedures and which is traceable to primary pH measurement metrology. High-precision spectrophotometric measurements of seawater pH using an indicator dye such as meta-cresol purple (mCP) are well established. However, traceability of these measurements to the International System of Units (SI) additionally requires characterizing the spectrophotometric pH response of the dye in multiple artificial seawater buffers that themselves are benchmarked via primary pH (Harned cell) measurements at a range of pH, salinity, and temperature. NIST is currently developing such a mCP pH RM using this approach. This material will also incorporate new procedures developed at NIST for assessing the purity and homogeneity of the mCP reagent itself. The resulting mCP will provide long-term (years) stability and ease of shipment compared to artificial seawater pH buffers. These efforts will provide the oceanographic user community with a NIST issued mCP (RM), characterized as to its molar absorptivity values and acid dissociation constants (pKa), with uncertainties that comply with the Guide to the Expression of Uncertainty in Measurement (GUM).

Ethanol-diesel fuel blends -- a review.

PubMed

Hansen, Alan C; Zhang, Qin; Lyne, Peter W L

2005-02-01

Ethanol is an attractive alternative fuel because it is a renewable bio-based resource and it is oxygenated, thereby providing the potential to reduce particulate emissions in compression-ignition engines. In this review the properties and specifications of ethanol blended with diesel fuel are discussed. Special emphasis is placed on the factors critical to the potential commercial use of these blends. These factors include blend properties such as stability, viscosity and lubricity, safety and materials compatibility. The effect of the fuel on engine performance, durability and emissions is also considered. The formulation of additives to correct certain key properties and maintain blend stability is suggested as a critical factor in ensuring fuel compatibility with engines. However, maintaining vehicle safety with these blends may entail fuel tank modifications. Further work is required in specifying acceptable fuel characteristics, confirming the long-term effects on engine durability, and ensuring safety in handling and storing ethanol-diesel blends.

Ferromagnetic, folded electrode composite as a soft interface to the skin for long-term electrophysiological recording.

PubMed

Jang, Kyung-In; Jung, Han Na; Lee, Jung Woo; Xu, Sheng; Liu, Yu Hao; Ma, Yinji; Jeong, Jae-Woong; Song, Young Min; Kim, Jeonghyun; Kim, Bong Hun; Banks, Anthony; Kwak, Jean Won; Yang, Yiyuan; Shi, Dawei; Wei, Zijun; Feng, Xue; Paik, Ungyu; Huang, Yonggang; Ghaffari, Roozbeh; Rogers, John A

2016-10-25

This paper introduces a class of ferromagnetic, folded, soft composite material for skin-interfaced electrodes with releasable interfaces to stretchable, wireless electronic measurement systems. These electrodes establish intimate, adhesive contacts to the skin, in dimensionally stable formats compatible with multiple days of continuous operation, with several key advantages over conventional hydrogel based alternatives. The reported studies focus on aspects ranging from ferromagnetic and mechanical behavior of the materials systems, to electrical properties associated with their skin interface, to system-level integration for advanced electrophysiological monitoring applications. The work combines experimental measurement and theoretical modeling to establish the key design considerations. These concepts have potential uses across a diverse set of skin-integrated electronic technologies.

Protective Coating

NASA Technical Reports Server (NTRS)

1984-01-01

Inorganic Coatings, Inc.'s K-Zinc 531 protective coating is water-based non-toxic, non-flammable and has no organic emissions. High ratio silicate formula bonds to steel, and in 30 minutes, creates a very hard ceramic finish with superior adhesion and abrasion resistance. Improved technology allows application over a minimal commercial sandblast, fast drying in high humidity conditions and compatibility with both solvent and water-based topcoats. Coating is easy to apply and provides long term protection with a single application. Zinc rich coating with water-based potassium silicate binder offers cost advantages in materials, labor hours per application, and fewer applications over a given time span.

Propellant/material compatibility program and results: Ten-year milestones

NASA Technical Reports Server (NTRS)

Moran, C.; Bjorkland, R.

1982-01-01

The analyses and results of a test program to establish the effects of long term (10 years or more) contact of materials with earth-storable propellants for the purpose of designing chemical propulsion system components which are used for current as well as future planetary spacecraft are described. The period from the publication of JPL TM 33-779 IN 1976 through the testing accomplished in 1981 is covered. The following propellants are reported herein: hydrazine, monomethylhydrazine and nitrogen tetroxide. Materials included the following: aluminum alloys, corrosion resistant steels and a titanium alloy. The results of the testing of more than 80 specimens are included. Material ratings relative to the ten year milepost were assigned. Some evidence of propellant decomposition was found. Titanium is rated as acceptable for ten year applications. Aluminum and stainless steel alloys are also rated as acceptable with few restrictions.

Compatibility of Niobium Alloys and Superalloys in a Flowing He-Xe Power Conversion System

NASA Technical Reports Server (NTRS)

Bowman, Cheryl L.; Ritzert, Frank J.; Smialek, James L.; Jaster, Mark L.; rker, Samuel P.

2004-01-01

Proposed concepts for an ambitious mission to explore Jupiter's three icy moons place significant demands on the various spacecraft systems. There are many challenges related to the high output power conversion systems being considered, and one example is the need to ensure system compatibility at all levels. The utilization of appropriate materials for component structures is important to ensuring long mission life. Refractory metal alloys have attractive high-temperature properties in inert environments, but these alloys are sometimes susceptible to contamination. Potential material compatibility issues exist between refractory metal candidates and more conventional alloys. Nb-1Zr has long been considered one of the most well characterized refractory alloys that is well suited for elevated-temperature use and liquid-metal compatibility. However, previous studies have suggested that niobium alloys can not co-exist in a closed system with traditional stainless steels or superalloys due to transport of contaminants. The relevance of this information to a proposed power conversion system is discussed. Also, experiments and fundamental calculations are being performed to determine contamination transport from candidate superalloys to Nb-1Zr in a closed system with an inert carrier gas. Potential protective schemes are explored to ensure system level compatibility between the refractory alloy Nb-1Zr and a nickel-based superalloy.

Examining ABO compatible donors in double lung transplants during the era of lung allocation score.

PubMed

Taghavi, Sharven; Jayarajan, Senthil N; Furuya, Yuka; Komaroff, Eugene; Shiose, Akira; Leotta, Eros; Hisamoto, Kazuhiro; Patel, Namrata; Cordova, Francis; Criner, Gerard; Guy, T Sloane; Toyoda, Yoshiya

2014-10-01

The short-term and long-term effect of using ABO compatible donors in the era of lung allocation score is unknown. This study determined if carefully selected ABO compatible donors could be used in double lung transplantation (DLT) with good outcomes. The United Network for Organ Sharing database was retrospectively reviewed for adult DLT from May 2005 to December 2011. Of 6,655 double lung transplants, 493 (7.4%) were with ABO compatible donors and 6,162 (92.6%) were with ABO identical donors. In multivariate analysis, use of ABO compatible donors was not associated with mortality at 30 days (HR, 1.16; 95% CI, 0.76 to 1.79, p = 0.49), 1 year (HR, 1.10; 95% CI, 0.86 to 1.42, p = 0.46), and 5 years (HR, 1.06; 95% CI, 0.83 to 1.34, p = 0.65). Variables associated with mortality at 5 years were donor female sex, donor age 60 years or greater, prolonged ischemic time, increasing recipient creatinine, recipient age, race mismatch, and mechanical ventilation or extracorporeal membrane oxygenation as a bridge to transplantation. Length of stay was longer in the ABO compatible group (30.9 vs 25.9 days, p = 0.001). Acute rejection episodes on index hospitalization (8.8 vs. 8.9%, p = 1.00), peak posttransplant forced expiratory volume in 1 second (FEV1) (82.7 vs 79.7%, p = 0.053), and decrement in FEV1 over time were not different (p = 0.13). Freedom from bronchiolitis obliterans syndrome was similar (1,475 vs 1,454 days, p = 0.17). The use of ABO compatible donors in the era of lung allocation score was not associated with short-term or long-term mortality and resulted in equivalent posttransplant lung function. A DLT with carefully selected ABO compatible donors can result in excellent outcomes. Copyright © 2014 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Recent progress in stabilizing hybrid perovskites for solar cell applications

NASA Astrophysics Data System (ADS)

Chen, Jianqing; Cai, Xin; Yang, Donghui; Song, Dan; Wang, Jiajia; Jiang, Jinghua; Ma, Aibin; Lv, Shiquan; Hu, Michael Z.; Ni, Chaoying

2017-07-01

Hybrid inorganic-organic perovskites have quickly evolved as a promising group of materials for solar cells and optoelectronic applications mainly owing to the inexpensive materials, relatively simple and versatile fabrication and high power conversion efficiency (PCE). The certified energy conversion efficiency for perovskite solar cell (PSC) has reached above 20%, which is compatible to the current best for commercial applications. However, long-term stabilities of the materials and devices remain to be the biggest challenging issue for realistic implementation of the PSCs. This article discusses the key issues related to the stability of perovskite absorbing layer including crystal structural stability, chemical stability under moisture, oxygen, illumination and interface reaction, effects of electron-transporting materials (ETM), hole-transporting materials (HTM), contact electrodes, ion migration and preparation conditions. Towards the end, prospective strategies for improving the stability of PSCs are also briefly discussed and summarized. We focus on recent understanding of the stability of materials and devices and our perspectives about the strategies for the stability improvement.

Oxygen Compatibility Assessment of Components and Systems

NASA Technical Reports Server (NTRS)

Stoltzfus, Joel; Sparks, Kyle

2010-01-01

Fire hazards are inherent in oxygen systems and a storied history of fires in rocket engine propulsion components exists. To detect and mitigate these fire hazards requires careful, detailed, and thorough analyses applied during the design process. The oxygen compatibility assessment (OCA) process designed by NASA Johnson Space Center (JSC) White Sands Test Facility (WSTF) can be used to determine the presence of fire hazards in oxygen systems and the likelihood of a fire. This process may be used as both a design guide and during the approval process to ensure proper design features and material selection. The procedure for performing an OCA is a structured step-by-step process to determine the most severe operating conditions; assess the flammability of the system materials at the use conditions; evaluate the presence and efficacy of ignition mechanisms; assess the potential for a fire to breach the system; and determine the reaction effect (the potential loss of life, mission, and system functionality as the result of a fire). This process should be performed for each component in a system. The results of each component assessment, and the overall system assessment, should be recorded in a report that can be used in the short term to communicate hazards and their mitigation and to aid in system/component development and, in the long term, to solve anomalies that occur during engine testing and operation.

An experimental study on the compatibility of acetone with aluminum flat-plate heat pipes

NASA Astrophysics Data System (ADS)

Hsieh, Jui-Ching; Lin, David T. W.; Huang, Hsin-Jung; Yang, Tzu-Wei

2014-04-01

This study investigates the compatibility of aluminum flat-plate heat pipes (FPHPs) used for filling acetone as a working fluid after long-term operation of and the non-condensable gas (NCG) exhausting process. The rate of NCG generation substantially decreased after conducting the NCG exhausting process, proving the compatibility of acetone with the aluminum FPHPs. However, the thermal resistance was not enhanced because hydroxide bayerite (Al(OH)3) was generated as a product of the reaction.

Diffusion, Thermal Properties and Chemical Compatibilities of Select MAX Phases with Materials For Advanced Nuclear Systems

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

Barsoum, Michel; Bentzel, Grady; Tallman, Darin J.

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 chosenmore » 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.« less

Adaptable Hydrogel Networks with Reversible Linkages for Tissue Engineering

PubMed Central

Wang, Huiyuan

2015-01-01

Adaptable hydrogels have recently emerged as a promising platform for three-dimensional (3D) cell encapsulation and culture. In conventional, covalently crosslinked hydrogels, degradation is typically required to allow complex cellular functions to occur, leading to bulk material degradation. In contrast, adaptable hydrogels are formed by reversible crosslinks. Through breaking and re-forming of the reversible linkages, adaptable hydrogels can be locally modified to permit complex cellular functions while maintaining their long-term integrity. In addition, these adaptable materials can have biomimetic viscoelastic properties that make them well suited for several biotechnology and medical applications. In this review, adaptable hydrogel design considerations and linkage selections are overviewed, with a focus on various cell compatible crosslinking mechanisms that can be exploited to form adaptable hydrogels for tissue engineering. PMID:25989348

An RFID-based on-lens sensor system for long-term IOP monitoring.

PubMed

Hsu, Shun-Hsi; Chiou, Jin-Chern; Liao, Yu-Te; Yang, Tzu-Sen; Kuei, Cheng-Kai; Wu, Tsung-Wei; Huang, Yu-Chieh

2015-01-01

In this paper, an RFID-based on-lens sensor system is proposed for noninvasive long-term intraocular pressure monitoring. The proposed sensor IC, fabricated in a 0.18um CMOS process, consists of capacitive sensor readout circuitry, RFID communication circuits, and digital processing units. The sensor IC is integrated with electroplating capacitive sensors and a receiving antenna on the contact lens. The sensor IC can be wirelessly powered, communicate with RFID compatible equipment, and perform IOP measurement using on-lens capacitive sensor continuously from a 2cm distance while the incident power from an RFID reader is 20 dBm. The proposed system is compatible to Gen2 RFID protocol, extending the flexibility and reducing the self-developed firmware efforts.

Preparation of Gd Loaded Liquid Scintillator for Daya Bay Neutrino Experiment

NASA Astrophysics Data System (ADS)

Ya-yun, Ding; Zhi-yong, Zhang

2010-05-01

Gadolinium loaded liquid scintillator (Gd-LS) is an excellent target material for reactor antineutrino experiments. Ideal Gd-LS should have long attenuation length, high light yield, long term stability, low toxicity, and should be compatible with the material used to build the detector. We have developed a new Gd-LS recipe in which carboxylic acid 3,5,5-trimethylhexanoic acid is used as the complexing ligand to gadolinium, 2,5-diphenyloxazole (PPO) and 1,4-bis[2-methylstyryl]benzene (bis-MSB) are used as primary fluor and wavelength shifter, respectively. The scintillator base is linear alkyl benzene (LAB). Eight hundred liters of Gd-LS has been synthesized and tested in a prototype detector. Results show that the Gd-LS has high quality and is suitable for underground experiments in large quantity. Large scale production facility has been built. A full batch production of 4 t Gd-LS has been produced and monitored for several months. The production of 180 t Gd-LS will be carried out in the near future.

Oxygen Compatibility of Brass-Filled PTFE Compared to Commonly Used Fluorinated Polymers for Oxygen Systems

NASA Technical Reports Server (NTRS)

Herald, Stephen D.; Frisby, Paul M.; Davis, Samuel Eddie

2009-01-01

Safe and reliable seal materials for high-pressure oxygen systems sometimes appear to be extinct species when sought out by oxygen systems designers. Materials that seal well are easy to find, but these materials are typically incompatible with oxygen, especially in cryogenic liquid form. This incompatibility can result in seals that leak, or much worse, seals that easily ignite and burn during use. Materials that are compatible with oxygen are easy to find, such as the long list of compatible metals, but these metallic materials are limiting as seal materials. A material that seals well and is oxygen compatible has been the big game in the designer's safari. Scientists at the Materials Combustion Research Facility (MCRF), part of NASA/Marshall Space Flight Center (MSFC), are constantly searching for better materials and processes to improve the safety of oxygen systems. One focus of this effort is improving the characteristics of polymers used in the presence of an oxygen enriched environment. Very few systems can be built which contain no polymeric materials; therefore, materials which have good impact resistance, low heat of combustion, high auto-ignition temperature and that maintain good mechanical properties are essential. The scientists and engineers at the Materials Combustion Research Facility, in cooperation with seal suppliers, are currently testing a new formulation of polytetrafluoroethylene (PTFE) with Brass filler. This Brass-filled PTFE is showing great promise as a seal and seat material for high pressure oxygen systems. Early research has demonstrated very encouraging results, which could rank this material as one of the best fluorinated polymers ever tested. This paper will compare the data obtained for Brass-filled PTFE with other fluorinated polymers, such as TFE-Teflon (PTFE) , Kel-F 81, Viton A, Viton A-500, Fluorel , and Algoflon . A similar metal filled fluorinated polymer, Salox-M , was tested in comparison to Brass-filled PTFE to demonstrate the importance of the metal chosen and relative percentage of filler. General conclusions on the oxygen compatibility of this formulation are drawn, with an emphasis on comparing and contrasting the materials performance to the performance of the current state-of-the-art oxygen compatible polymers.

Poly(hydroxyalkanoate)s-Based Hydrophobic Coatings for the Protection of Stone in Cultural Heritage

PubMed Central

Andreotti, Serena; Fabbri, Paola

2018-01-01

Reversibility is a mandatory requirement for materials used in heritage conservation, including hydrophobic protectives. Nevertheless, current protectives for stone are not actually reversible as they remain on the surfaces for a long time after their hydrophobicity is lost and can hardly be removed. Ineffective and aged coatings may jeopardise the stone re-treatability and further conservation interventions. This paper aims at investigating the performance of PHAs-based coatings for stone protection, their main potential being the ‘reversibility by biodegradation’ once water repellency ended. The biopolymer coatings were applied to three different kinds of stone, representative of lithotypes used in historic architecture: sandstone, limestone and marble. Spray, poultice and dip-coating were tested as coating techniques. The effectiveness and compatibility of the protectives were evaluated in terms of capillary water absorption, static and dynamic contact angles, water vapour diffusion, colour alteration and surface morphology. The stones’ wettability after application of two commercial protectives was investigated too, for comparison. Finally, samples were subjected to artificial ageing to investigate their solar light stability. Promising results in terms of efficacy and compatibility were obtained, although the PHAs-based formulations developed here still need improvement for increased durability and on-site applicability. PMID:29361721

Materials Compatibility Testing in Concentrated Hydrogen Peroxide

NASA Technical Reports Server (NTRS)

Boxwell, R.; Bromley, G.; Mason, D.; Crockett, D.; Martinez, L.; McNeal, C.; Lyles, G. (Technical Monitor)

2000-01-01

Materials test methods from the 1960's have been used as a starting point in evaluating materials for today's space launch vehicles. These established test methods have been modified to incorporate today's analytical laboratory equipment. The Orbital test objective was to test a wide range of materials to incorporate the revolution in polymer and composite materials that has occurred since the 1960's. Testing is accomplished in 3 stages from rough screening to detailed analytical tests. Several interesting test observations have been made during this testing and are included in the paper. A summary of the set-up, test and evaluation of long-term storage sub-scale tanks is also included. This sub-scale tank test lasted for a 7-month duration prior to being stopped due to a polar boss material breakdown. Chemical evaluations of the hydrogen peroxide and residue left on the polar boss surface identify the material breakdown quite clearly. The paper concludes with recommendations for future testing and a specific effort underway within the industry to standardize the test methods used in evaluating materials.

New advances in MR-compatible bioartificial liver

PubMed Central

Jeffries, Rex E.; Macdonald, Jeffrey M.

2015-01-01

MR-compatible bioartificial liver (BAL) studies have been performed for 30 years and are reviewed. There are two types of study: (i) metabolism and drug studies using multinuclear MRS; primarily short-term (< 8 h) studies; (ii) the use of multinuclear MRS and MRI to noninvasively define the features and functions of BAL systems for long-term liver tissue engineering. In the latter, these systems often undergo not only modification of the perfusion system, but also the construction of MR radiofrequency probes around the bioreactor. We present novel MR-compatible BALs and the use of multinuclear MRS (13C, 19F, 31P) for the noninvasive monitoring of their growth, metabolism and viability, as well as 1H MRI methods for the determination of flow profiles, diffusion, cell distribution, quality assurance and bioreactor integrity. Finally, a simple flexible coil design and circuit, and life support system, are described that can make almost any BAL MR-compatible. PMID:22351642

A practical approach to spectral calibration of short wavelength infrared hyper-spectral imaging systems

NASA Astrophysics Data System (ADS)

Bürmen, Miran; Pernuš, Franjo; Likar, Boštjan

2010-02-01

Near-infrared spectroscopy is a promising, rapidly developing, reliable and noninvasive technique, used extensively in the biomedicine and in pharmaceutical industry. With the introduction of acousto-optic tunable filters (AOTF) and highly sensitive InGaAs focal plane sensor arrays, real-time high resolution hyper-spectral imaging has become feasible for a number of new biomedical in vivo applications. However, due to the specificity of the AOTF technology and lack of spectral calibration standardization, maintaining long-term stability and compatibility of the acquired hyper-spectral images across different systems is still a challenging problem. Efficiently solving both is essential as the majority of methods for analysis of hyper-spectral images relay on a priori knowledge extracted from large spectral databases, serving as the basis for reliable qualitative or quantitative analysis of various biological samples. In this study, we propose and evaluate fast and reliable spectral calibration of hyper-spectral imaging systems in the short wavelength infrared spectral region. The proposed spectral calibration method is based on light sources or materials, exhibiting distinct spectral features, which enable robust non-rigid registration of the acquired spectra. The calibration accounts for all of the components of a typical hyper-spectral imaging system such as AOTF, light source, lens and optical fibers. The obtained results indicated that practical, fast and reliable spectral calibration of hyper-spectral imaging systems is possible, thereby assuring long-term stability and inter-system compatibility of the acquired hyper-spectral images.

Long-Term Stable Adhesion for Conducting Polymers in Biomedical Applications: IrOx and Nanostructured Platinum Solve the Chronic Challenge.

PubMed

Boehler, Christian; Oberueber, Felix; Schlabach, Sabine; Stieglitz, Thomas; Asplund, Maria

2017-01-11

Conducting polymers (CPs) have frequently been described as outstanding coating materials for neural microelectrodes, providing significantly reduced impedance or higher charge injection compared to pure metals. Usability has until now, however, been limited by poor adhesion of polymers like poly(3,4-ethylenedioxythiophene) (PEDOT) to metallic substrates, ultimately precluding long-term applications. The aim of this study was to overcome this weakness of CPs by introducing two novel adhesion improvement strategies that can easily be integrated with standard microelectrode fabrication processes. Iridium Oxide (IrOx) demonstrated exceptional stability for PEDOT coatings, resulting in polymer survival over 10 000 redox cycles and 110 days under accelerated aging conditions at 60 °C. Nanostructured Pt was furthermore introduced as a purely mechanical adhesion promoter providing 10-fold adhesion improvement compared to smooth Pt substrates by simply altering the morphology of Pt. This layer can be realized in a very simple process that is compatible with any electrode design, turning nanostructured Pt into a universal adhesion layer for CP coatings. By the introduction of these adhesion-promoting strategies, the weakness of CP-based neural probes can ultimately be eliminated and true long-term stable use of PEDOT on neural probes will be possible in future electrode generations.

Application of Laminar Flow Control Technology to Long-Range Transport Design

NASA Technical Reports Server (NTRS)

Gratzer, L. B.; George-Falvy, D.

1978-01-01

The impact of laminar flow control (LFC) technology on aircraft structural design concepts and systems was discussed and the corresponding benefits were shown in terms of performance and fuel economy. Specific topics discussed include: (1) recent advances in laminar boundary layer development and stability analysis techniques in terms of suction requirements and wing suction surface design; (2) validation of theory and realistic simulation of disturbances and off-design conditions by wind tunnel testing; (3) compatibility of aerodynamic design of airfoils and wings with LFC requirements; (4) structural alternatives involving advanced alloys or composites in combinations made possible by advanced materials processing and manufacturing techniques; (5) addition of suction compressor and drive units and their location on the aircraft; and (6) problems associated with operation of LFC aircraft, including accumulation of insects at low altitudes and environmental considerations.

Effect of hydrogen on the strength and microstructure of selected ceramics

NASA Technical Reports Server (NTRS)

Herbell, Thomas P.; Eckel, Andrew J.; Hull, David R.; Misra, Ajay K.

1990-01-01

Ceramics in monolithic form and as composite constituents in the form of fibers, matrices, and coatings are currently being considered for a variety of high-temperature applications in aeronautics and space. Many of these applications involve exposure to a hydrogen-containing environment. The compatibility of selected ceramics in gaseous high-temperature hydrogen is assessed. Environmental stability regimes for the long term use of ceramic materials are defined by the parameters of temperature, pressure, and moisture content. Thermodynamically predicted reactions between hydrogen and several monolithic ceramics are compared with actual performance in a controlled environment. Morphology of hydrogen attack and the corresponding strength degradation is reported for silicon carbide, silicon nitride, alumina, magnesia, and mullite.

Fatigue behaviour analysis for the durability prequalification of strengthening mortars

NASA Astrophysics Data System (ADS)

Bocca, P.; Grazzini, A.; Masera, D.

2011-07-01

An innovative laboratory procedure used as a preliminary design stage for the pre-qualification of strengthening mortars applied to historical masonry buildings is described. In the analysis of the behaviour of masonry structures and their constituent materials, increasing importance has been assumed by the study of the long-term evolution of deformation and mechanical characteristics, which may be affected by both loading and environmental conditions. Through static and fatigue tests on mixed specimens historical brick-reinforced mortar it has been possible to investigate the durability of strengthening materials, in order to select, from a range of alternatives, the most suitable for the historical masonry. Cyclic fatigue stress has been applied to accelerate the static creep and to forecast the corresponding creep behaviour of the historical brick-strengthening mortar system under static long-time loading. This methodology has proved useful in avoiding the errors associated with materials that are not mechanically compatible and guarantees the durability of strengthening work. The experimental procedure has been used effectively in the biggest restoration building site in Europe, the Royal Palace of Venaria, and it is in progress of carrying out at the Special Natural Reserve of the Sacro Monte di Varallo, in Piedmont (Italy).

Construction materials, monuments and environment

NASA Astrophysics Data System (ADS)

Prikryl, R.; Siegesmund, S.; Török, A.; Brimblecombe, P.; Gomez-Heras, M.

2012-04-01

Construction materials (natural stone, aggregates, bricks, cement, lime, mortar, etc.) form a wide and heterogeneous group both from the genetic and technological point of view. These materials deserve attention from the scientific community due to their long-term use, importance for society and sensitivity to the environment. Most geomaterials have also been used in important monuments designated as a part of the World Cultural Heritage and/or make part of national monuments. Despite of the wide-ranges of studies and our rapidly increasing understanding of material behaviour, our knowledge is still rather limited in many aspects. This concerns the characterisation of traditional raw materials, the knowledge of their processing and use, and/or durability and compatibility assessment. The exploitation and sustainable use of these materials are also new and emerging challenges in the modern society. The use of local materials for monuments can be considered as a part of our cultural and technological heritage, which has, however, significantly deteriorated during the past several decades. This paper summarizes the general topics related to a modern analysis of traditional construction materials derived from the Earth, and on the characteristic aspects of the behaviour of these materials on selected monuments.

Forum for discussion and debate

NASA Technical Reports Server (NTRS)

1981-01-01

The application of statistical methods to meteorological data for which there are long, compatible series, and where known trend changes took place were suggested. The effects of optical wedge deterioration, atmospheric aerosol variation, solar irradiance variations, etc., are evaluated. It is recommended that coupled satellite ground based observational system is required to determine global long term trends.

Preparation of Gd Loaded Liquid Scintillator for Daya Bay Neutrino Experiment

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

Ding Yayun; Zhang Zhiyong

2010-05-12

Gadolinium loaded liquid scintillator (Gd-LS) is an excellent target material for reactor antineutrino experiments. Ideal Gd-LS should have long attenuation length, high light yield, long term stability, low toxicity, and should be compatible with the material used to build the detector. We have developed a new Gd-LS recipe in which carboxylic acid 3,5,5-trimethylhexanoic acid is used as the complexing ligand to gadolinium, 2,5-diphenyloxazole (PPO) and 1,4-bis[2-methylstyryl]benzene (bis-MSB) are used as primary fluor and wavelength shifter, respectively. The scintillator base is linear alkyl benzene (LAB). Eight hundred liters of Gd-LS has been synthesized and tested in a prototype detector. Results showmore » that the Gd-LS has high quality and is suitable for underground experiments in large quantity. Large scale production facility has been built. A full batch production of 4 t Gd-LS has been produced and monitored for several months. The production of 180 t Gd-LS will be carried out in the near future.« less

Is Ecosystem-Atmosphere Observation in Long-Term Networks actually Science?

NASA Astrophysics Data System (ADS)

Schmid, H. P. E.

2015-12-01

Science uses observations to build knowledge by testable explanations and predictions. The "scientific method" requires controlled systematic observation to examine questions, hypotheses and predictions. Thus, enquiry along the scientific method responds to questions of the type "what if …?" In contrast, long-term observation programs follow a different strategy: we commonly take great care to minimize our influence on the environment of our measurements, with the aim to maximize their external validity. We observe what we think are key variables for ecosystem-atmosphere exchange and ask questions such as "what happens next?" or "how did this happen?" This apparent deviation from the scientific method begs the question whether any explanations we come up with for the phenomena we observe are actually contributing to testable knowledge, or whether their value remains purely anecdotal. Here, we present examples to argue that, under certain conditions, data from long-term observations and observation networks can have equivalent or even higher scientific validity than controlled experiments. Internal validity is particularly enhanced if observations are combined with modeling. Long-term observations of ecosystem-atmosphere fluxes identify trends and temporal scales of variability. Observation networks reveal spatial patterns and variations, and long-term observation networks combine both aspects. A necessary condition for such observations to gain validity beyond the anecdotal is the requirement that the data are comparable: a comparison of two measured values, separated in time or space, must inform us objectively whether (e.g.) one value is larger than the other. In turn, a necessary condition for the comparability of data is the compatibility of the sensors and procedures used to generate them. Compatibility ensures that we compare "apples to apples": that measurements conducted in identical conditions give the same values (within suitable uncertainty intervals). In principle, a useful tool to achieve comparability and compatibility is the standardization of sensors and methods. However, due to the diversity of ecosystems and settings, standardization in ecosystem-atmosphere exchange is difficult. We discuss some of the challenges and pitfalls of standardization across networks.

Flat-plate solar array project. Volume 7: Module encapsulation

NASA Astrophysics Data System (ADS)

Cuddihy, E.; Coulbert, C.; Gupta, A.; Liang, R.

1986-10-01

The objective of the Encapsulation Task was to develop, demonstrate, and qualify photovoltaic (PV) module encapsulation systems that would provide 20 year (later decreased to 30 year) life expectancies in terrestrial environments, and which would be compatible with the cost and performance goals of the Flat-Plate Solar Array (FSA) Project. The scope of the Encapsulation Task included the identification, development, and evaluation of material systems and configurations required to support and protect the optically and electrically active solar cell circuit components in the PV module operating environment. Encapsulation material technologies summarized include the development of low cost ultraviolet protection techniques, stable low cost pottants, soiling resistant coatings, electrical isolation criteria, processes for optimum interface bonding, and analytical and experimental tools for evaluating the long term durability and structural adequacy of encapsulated modules. Field testing, accelerated stress testing, and design studies have demonstrated that encapsulation materials, processes, and configurations are available that meet the FSA cost and performance goals.

Flat-plate solar array project. Volume 7: Module encapsulation

NASA Technical Reports Server (NTRS)

Cuddihy, E.; Coulbert, C.; Gupta, A.; Liang, R.

1986-01-01

The objective of the Encapsulation Task was to develop, demonstrate, and qualify photovoltaic (PV) module encapsulation systems that would provide 20 year (later decreased to 30 year) life expectancies in terrestrial environments, and which would be compatible with the cost and performance goals of the Flat-Plate Solar Array (FSA) Project. The scope of the Encapsulation Task included the identification, development, and evaluation of material systems and configurations required to support and protect the optically and electrically active solar cell circuit components in the PV module operating environment. Encapsulation material technologies summarized include the development of low cost ultraviolet protection techniques, stable low cost pottants, soiling resistant coatings, electrical isolation criteria, processes for optimum interface bonding, and analytical and experimental tools for evaluating the long term durability and structural adequacy of encapsulated modules. Field testing, accelerated stress testing, and design studies have demonstrated that encapsulation materials, processes, and configurations are available that meet the FSA cost and performance goals.

The Blood Compatibilities of Blood Purification Membranes and Other Materials Developed in Japan

PubMed Central

Abe, Takaya; Kato, Karen; Fujioka, Tomoaki; Akizawa, Tadao

2011-01-01

The biocompatibilities in blood purification therapy are defined as “a concept to stipulate safety of blood purification therapy by an index based on interaction in the body arising from blood purification therapy itself.” The biocompatibilities are associated with not only materials to be used but also many factors such as sterilization method and eluted substance. It is often evaluated based on impacts on cellular pathways and on humoral pathways. Since the biocompatibilities of blood purification therapy in particular hemodialysis are not just a prognostic factor for dialysis patients but a contributory factor for long-term complications, it should be considered with adequate attention. It is important that blood purification therapy should be performed by consistently evaluating not only risks associated with these biocompatibilities but also the other advantages obtained from treatments. In this paper, the biocompatibilities of membrane and adsorption material based on Japanese original which are used for blood purification therapy are described. PMID:21969830

30 CFR 816.106 - Backfilling and grading: Previously mined areas.

Code of Federal Regulations, 2010 CFR

2010-07-01

... operation shall be included within the permit area. (2) The backfill shall be graded to a slope which is compatible with the approved postmining land use and which provides adequate drainage and long-term stability...

30 CFR 817.106 - Backfilling and grading: Previously mined areas.

Code of Federal Regulations, 2010 CFR

2010-07-01

... operation shall be included within the permit area. (2) The backfill shall be graded to a slope which is compatible with the approved postmining land use and which provides adequate drainage and long-term stability...

ICT use for information management in healthcare system for chronic disease patient

NASA Astrophysics Data System (ADS)

Wawrzyniak, Zbigniew M.; Lisiecka-Biełanowicz, Mira

2013-10-01

Modern healthcare systems are designed to fulfill needs of the patient, his system environment and other determinants of the treatment with proper support of technical aids. A whole system of care is compatible to the technical solutions and organizational framework based on legal rules. The purpose of this study is to present how can we use Information and Communication Technology (ICT) systemic tools in a new model of patient-oriented care, improving the effectiveness of healthcare for patients with chronic diseases. The study material is the long-term process of healthcare for patients with chronic illness. Basing on the knowledge of the whole circumstances of patient's ecosystem and his needs allow us to build a new ICT model of long term care. The method used is construction, modeling and constant improvement the efficient ICT layer for the patient-centered healthcare model. We present a new constructive approach to systemic process how to use ICT for information management in healthcare system for chronic disease patient. The use of ICT tools in the model for chronic disease can improve all aspects of data management and communication, and the effectiveness of long-term complex healthcare. In conclusion: ICT based model of healthcare can be constructed basing on the interactions of ecosystem's functional parts through information feedback and the provision of services and models as well as the knowledge of the patient itself. Systematic approach to the model of long term healthcare assisted functionally by ICT tools and data management methods will increase the effectiveness of patient care and organizational efficiency.

5th Annual Provider Software Buyer's Guide.

PubMed

1995-03-01

To help long term care providers find new ways to improve quality of care and efficiency, PROVIDER presents the fifth annual listing of software firms marketing computer programs for all areas of long term care operations. On the following five pages, more than 70 software firms display their wares, with programs such as minimum data set and care planning, dietary, accounting and financials, case mix, and medication administration records. The guide also charts compatible hardware, integration ability, telephone numbers, company contacts, and easy-to-use reader service numbers.

The coupling between the ionosphere and the protonosphere and its implications on the long term variations of ionospheric electron content

NASA Technical Reports Server (NTRS)

Waldman, H.

1971-01-01

The long-term variations in the daytime exchange flux are estimated with the use of model hydrogen concentrations based on the inverse relationship between the abundance of neutral hydrogen and the neutral temperature in the thermosphere. The results are found to be compatible with the observed long-term behavior of the ionospheric electron content at a midlatitude location, as revealed by Faraday observations using geostationary satellites. The basic processes occurring in the ionosphere are reviewed, with emphasis on the concepts of limiting velocity and limiting flux. An approach to the problem of numerical simulation of the ionosphere is also presented and discussed.

Titanium-alloy, metallic-fluid heat pipes for space service

NASA Technical Reports Server (NTRS)

Morris, J. F.

1979-01-01

Reactivities of titanium limit its long-term terrestrial use for unprotected heat-pipe envelopes to about 870 K (1100 F). But this external thermochemical limitation disappears when considerations shift to space applications. In such hard-vacuum utilization much higher operating temperatures are possible. Primary restrictions in space environment result from vaporization, thermal creep, and internal compatibilities. Unfortunately, a respected head-pipe reference indicates that titanium is compatible only with cesium from the alkali-metal working-fluid family. This problem and others are subjects of the present paper which advocates titanium-alloy, metallic-fluid heat pipes for long-lived, weight-effective space service between 500 and 1300 K (440 and 1880 F).

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

Everett, M.; Davis, P.

LLNL and Optiphase resarched fiber optic based fluorescence lifetime instrumentation which, through the incorporation of innovative technology supplied by Optiphase Inc., could lead to a reliable, simplified, and low-cost system mutually compatible with future interests of the company and the long-term stability requirements of ESP sensors.

Synthetic cornea: biocompatibility and optics

NASA Astrophysics Data System (ADS)

Parel, Jean-Marie A.; Kaminski, Stefan; Fernandez, Viviana; Alfonso, E.; Lamar, Peggy; Lacombe, Emmanuel; Duchesne, Bernard; Dubovy, Sander; Manns, Fabrice; Rol, Pascal O.

2002-06-01

Purpose. Experimentally find a method to provide a safe surgical technique and an inexpensive and long lasting mesoplant for the restoration of vision in patients with bilateral corneal blindness due to ocular surface and stromal diseases. Methods. Identify the least invasive and the safest surgical technique for synthetic cornea implantation. Identify the most compatible biomaterials and the optimal shape a synthetic cornea must have to last a long time when implanted in vivo. Results. Penetrating procedures were deemed too invasive, time consuming, difficult and prone to long term complications. Therefore a non-penetrating delamination technique with central trephination was developed to preserve the integrity of Descemet's membrane and the anterior segment. Even though this approach limits the number of indications, it is acceptable since the majority of patients only have opacities in the stroma. The prosthesis was designed to fit in the removed tissue plane with its skirt fitted under the delaminated stroma. To improve retention, the trephination wall was made conical with the smallest opening on the anterior surface and a hat-shaped mesoplant was made to fit. The skirt was perforated in its perimeter to allow passage of nutrients and tissues ingrowths. To simplify the fabrication procedure, the haptic and optic were made of the same polymer. The intrastromal biocompatibility of several hydrogels was found superior to current clinically used PMMA and PTFE materials. Monobloc mesoplants made of 4 different materials were implanted in rabbits and followed weekly until extrusion occurred. Some remained optically clear allowing for fundus photography. Conclusions. Hydrogel synthetic corneas can be made to survive for periods longer than 1 year. ArF excimer laser photoablation studies are needed to determine the refractive correction potential of these mesoplants. A pilot FDA clinical trial is needed to assess the mesoplant efficacy and very long-term stability.

Tailoring of the titanium surface by immobilization of heparin/fibronectin complexes for improving blood compatibility and endothelialization: an in vitro study.

PubMed

Li, Guicai; Yang, Ping; Liao, Yuzhen; Huang, Nan

2011-04-11

To improve the blood compatibility and endothelialization simultaneously and to ensure the long-term effectiveness of the cardiovascular implants, we developed a surface modification method, enabling the coimmobilization of biomolecules to metal surfaces. In the present study, a heparin and fibronectin mixture (Hep/Fn) covalently immobilized on a titanium (Ti) substrate for biocompatibility was investigated. Different systems [N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide and N-hydroxysuccinimide, electrostatic] were used for the formation of Hep/Fn layers. Atomic force microscopy (AFM) showed that the roughness of the silanized Ti surface decreased after the immobilization of Hep/Fn. Fourier transform infrared spectroscopy (FTIR), Toluidine Blue O (TBO) test, and immunochemistry assay showed that Hep/Fn mixture was successfully immobilized on Ti surface. Blood compatibility tests (hemolysis rate, APTT, platelet adhesion, fibrinogen conformational change) showed that the coimmobilized films of Hep/Fn mixture reduced blood hemolysis rate, prolonged blood coagulation time, reduced platelets activation and aggregation, and induced less fibrinogen conformational change compared with a bare Ti surface. Endothelial cell (EC) seeding showed more EC with better morphology on pH 4 samples than on pH 7 and EDC/NHS samples, which showed rounded and aggregated cells. Systematic evaluation showed that the pH 4 samples also had much better blood compatibility. All results suggest that the coimmobilized films of Hep/Fn can confer excellent antithrombotic properties and with good endothelialization. We envisage that this method will provide a potential and effective solution for the surface modification of cardiovascular implant materials.

Biomaterials for drug delivery systems.

PubMed

Buckles, R G

1983-01-01

Drug delivery systems have unusual materials requirements which derive mainly from their therapeutic role: to administer drugs over prolonged periods of time at rates that are independent of patient-to-patient variables. The chemical nature of the surfaces of such devices may stimulate biorejection processes which can be enhanced or suppressed by the simultaneous presence of the drug that is being administered. Selection of materials for such systems is further complicated by the need for compatibility with the drug contained within the system. A review of selected drug delivery systems is presented. This leads to a definition of the technologies required to develop successfully such systems as well as to categorize the classes of drug delivery systems available to the therapist. A summary of the applications of drug delivery systems will also be presented. There are five major challenges to the biomaterials scientist: (1) how to minimize the influence on delivery rate of the transient biological response that accompanies implantation of any object; (2) how to select a composition, size, shape, and flexibility that optimizes biocompatibility; (3) how to make an intravascular delivery system that will retain long-term functionality; (4) how to make a percutaneous lead for those delivery systems that cannot be implanted but which must retain functionality for extended periods; and (5) how to make biosensors of adequate compatibility and stability to use with the ultimate drug delivery system-a system that operates with feedback control.

Effects of Vaporized Decontamination Systems on Selected Building Interior Materials: Vaporized Hydrogen Peroxide

DTIC Science & Technology

2009-01-01

surfaces in buildings following a terrorist attack using CB agents. Vaporized hydrogen peroxide ( VHP ) and Cl02 are decontamination technologies that...decontaminant. The focus of this technical report is the evaluation of the building interior materials and the Steris VHP technology. 15. SUBJECT...TERMS Material Compatibility VHP vaporized hydrogen peroxide 16. SECURITY CLASSIFICATION OF: a. REPORT U b. ABSTRACT U c. THIS PAGE U 17

Designing optimized ultra-lightweighted mirror structures made of Cesic for space and ground based applications

NASA Astrophysics Data System (ADS)

Hofbauer, Peter; Krödel, Matthias R.

2010-07-01

Today's space applications increasingly utilize lightweighted construction concepts, motivated by the demands of manufacturing and functionality, and by economics. Particularly for space optics, mirror stability and stiffness need to be maximized, while mass needs to be minimized. Therefore, mirror materials must possess, besides high material strength and manufacturing versatility, high thermal conductivity combined with low heat capacity and long-term stability against varying thermal loads. Additionally, optical surfaces need to be compatible with reflective coating materials. In order to achieve these requirements, the interplay between material properties and mirror design on one hand, and budgetary constraints on the other must be considered. In this paper, we address these issues by presenting an FEM design study of open and closed-back mirror structures with extremely thin reinforcing ribs, with the goal of obtaining optimal physical and optical characteristics. Furthermore, we show that ECM's carbon-fiber reinforced SiC composite, Cesic®, and its newly developed, HB-Cesic® , with their low CTE, low density, and high stiffness, are not only excellent mirror materials, but allow the rapid manufacturing of complex monolithic optical structures at reasonable cost.

Over-expression of FT1 in plum (Prunus domestica) results in phenotypes compatible with spaceflight: a potential new candidate crop for bioregenerative life support systems

USDA-ARS?s Scientific Manuscript database

Tree fruits (e.g., apples, plums, cherries) are appealing constituents of a crew menu for long-duration exploration missions (i.e., Mars), both in terms of their nutritive and menu diversity contributions. Although appealing, tree fruit species have long been precluded as candidate crops for use in...

Novel Polyimide Battery Separator Imbibed with Room-Temperature Ionic Liquids

NASA Technical Reports Server (NTRS)

Viggiano, Rocco; Nguyen, Baochau; Wu, James; Dai, Liming; Meador, Mary Ann

2017-01-01

The journey to Mars will require advancements in many existing technologies, including space power and energy storage systems. According to the 2015 NASA Technology Roadmaps, energy storage is a critical technology area to develop for both terrestrial as well as future long-term space missions. Currently, batteries represent one of the major areas in need of advancement, both in terms of energy density as well as safety. Recently, concerns regarding the fire safety of commercial lithium-ion batteries have prompted efforts to produce nonflammable battery components, namely the electrolyte and separator. Commercial lithium-ion batteries utilize polyolefin separators imbibed with a lithium salt dissolved in cyclic carbonates. This separator/electrolyte combination imparts good ionic conductivities in the range of 10(exp -2) to 10(exp -3) S/cm. However, the cyclic carbonates and polyolefin separator are inherently flammable. Room-temperature ionic liquids (RTILs) appear to be a safer alternative to cyclic carbonates. They offer good ionic conductivities, similar to those observed in cyclic carbonates, but are inherently nonvolatile and nonflammable giving them a safety advantage. Many promising RTILs for battery electrolytes are not compatible with commercial polyolefin separator materials. Polyimide aerogels possess an open-porous, fibrillar network architecture which offers a high degree of porosity (typically greater than 85 porous), required for lithium ion conduction, as well as good mechanical properties. Furthermore, these materials are compatible with all tested RTILs. By creating a polyimide gel and imbibing the gel with a RTIL containing a lithium salt instead of super critically drying them to form aerogels, a nonflammable separator/electrolyte system with conductivities in the range of 1x10(exp -3) S/cm has been demonstrated.

An overview on cellulose-based material in tailoring bio-hybrid nanostructured photocatalysts for water treatment and renewable energy applications.

PubMed

Mohamed, Mohamad Azuwa; Abd Mutalib, Muhazri; Mohd Hir, Zul Adlan; M Zain, M F; Mohamad, Abu Bakar; Jeffery Minggu, Lorna; Awang, Nor Asikin; W Salleh, W N

2017-10-01

A combination between the nanostructured photocatalyst and cellulose-based materials promotes a new functionality of cellulose towards the development of new bio-hybrid materials for various applications especially in water treatment and renewable energy. The excellent compatibility and association between nanostructured photocatalyst and cellulose-based materials was induced by bio-combability and high hydrophilicity of the cellulose components. The electron rich hydroxyl group of celluloses helps to promote superior interaction with photocatalyst. The formation of bio-hybrid nanostructured are attaining huge interest nowadays due to the synergistic properties of individual cellulose-based material and photocatalyst nanoparticles. Therefore, in this review we introduce some cellulose-based material and discusses its compatibility with nanostructured photocatalyst in terms of physical and chemical properties. In addition, we gather information and evidence on the fabrication techniques of cellulose-based hybrid nanostructured photocatalyst and its recent application in the field of water treatment and renewable energy. Copyright © 2017 Elsevier B.V. All rights reserved.

Analysis of the Influence of HLA-A Matching Relative to HLA-B and -DR Matching on Heart Transplant Outcomes

PubMed Central

Ansari, David; Bućin, Dragan; Höglund, Peter; Ohlsson, Mattias; Andersson, Bodil; Nilsson, Johan

2015-01-01

Background There are conflicting reports on the effect of donor-recipient HLA matching on outcomes in heart transplantation. The objective of this study was to investigate the effects of HLA-A matching relative to HLA-B and -DR matching on long-term survival in heart transplantation. Methods A total of 25 583 patients transplanted between 1988 and 2011 were identified from the International Society for Heart and Lung Transplantation registry. Transplants were divided into 2 donor-recipient matching groups: HLA-A–compatible (no HLA-A mismatches) and HLA-A–incompatible (1-2 HLA-A mismatches). Primary outcome was all-cause mortality. Secondary outcomes were graft failure-, cardiovascular-, infection-, or malignancy-related deaths. Results The risk of all-cause mortality 15 years after transplantation was higher for HLA-A–compatible (vs HLA-A–incompatible) grafts in patients who had HLA-B–, HLA-DR–, or HLA-B,DR–incompatible grafts (P = 0.027, P = 0.007, and P = 0.002, respectively) but not in HLA-B– and/or HLA-DR–compatible grafts. This was confirmed in multivariable Cox regression analysis where HLA-A compatibility (vs HLA-A incompatibility) was associated with higher mortality in transplants incompatible for HLA-DR or HLA-B and -DR (hazard ratio [HR], 1.59; 95% confidence interval [95% CI], 1.11-2.28; P = 0.012 and HR, 1.69; 95% CI, 1.17-2.43; P = 0.005, respectively). In multivariable analysis, the largest compromise in survival for HLA-A compatibility (vs HLA-incompatibility) was for chronic rejection in HLA-B– and -DR–incompatible grafts (HR, 1.91; 95% CI, 1.22-3.01; P = 0.005). Conclusions Decreased long-term survival in heart transplantation was associated with HLA-A compatibility in HLA-B,DR–incompatible grafts. PMID:27500238

Age of Red Cells for Transfusion and Outcomes in Critically Ill Adults.

PubMed

Cooper, D James; McQuilten, Zoe K; Nichol, Alistair; Ady, Bridget; Aubron, Cécile; Bailey, Michael; Bellomo, Rinaldo; Gantner, Dashiell; Irving, David O; Kaukonen, Kirsi-Maija; McArthur, Colin; Murray, Lynne; Pettilä, Ville; French, Craig

2017-11-09

It is uncertain whether the duration of red-cell storage affects mortality after transfusion among critically ill adults. In an international, multicenter, randomized, double-blind trial, we assigned critically ill adults to receive either the freshest available, compatible, allogeneic red cells (short-term storage group) or standard-issue (oldest available), compatible, allogeneic red cells (long-term storage group). The primary outcome was 90-day mortality. From November 2012 through December 2016, at 59 centers in five countries, 4994 patients underwent randomization and 4919 (98.5%) were included in the primary analysis. Among the 2457 patients in the short-term storage group, the mean storage duration was 11.8 days. Among the 2462 patients in the long-term storage group, the mean storage duration was 22.4 days. At 90 days, there were 610 deaths (24.8%) in the short-term storage group and 594 (24.1%) in the long-term storage group (absolute risk difference, 0.7 percentage points; 95% confidence interval [CI], -1.7 to 3.1; P=0.57). At 180 days, the absolute risk difference was 0.4 percentage points (95% CI, -2.1 to 3.0; P=0.75). Most of the prespecified secondary measures showed no significant between-group differences in outcome. The age of transfused red cells did not affect 90-day mortality among critically ill adults. (Funded by the Australian National Health and Medical Research Council and others; TRANSFUSE Australian and New Zealand Clinical Trials Registry number, ACTRN12612000453886 ; ClinicalTrials.gov number, NCT01638416 .).

Transmission of wireless neural signals through a 0.18 µm CMOS low-power amplifier.

PubMed

Gazziro, M; Braga, C F R; Moreira, D A; Carvalho, A C P L F; Rodrigues, J F; Navarro, J S; Ardila, J C M; Mioni, D P; Pessatti, M; Fabbro, P; Freewin, C; Saddow, S E

2015-01-01

In the field of Brain Machine Interfaces (BMI) researchers still are not able to produce clinically viable solutions that meet the requirements of long-term operation without the use of wires or batteries. Another problem is neural compatibility with the electrode probes. One of the possible ways of approaching these problems is the use of semiconductor biocompatible materials (silicon carbide) combined with an integrated circuit designed to operate with low power consumption. This paper describes a low-power neural signal amplifier chip, named Cortex, fabricated using 0.18 μm CMOS process technology with all electronics integrated in an area of 0.40 mm(2). The chip has 4 channels, total power consumption of only 144 μW, and is impedance matched to silicon carbide biocompatible electrodes.

National Research and Development Plan for Aviation Safety, Security, Efficiency and Environmental Compatibility.

DOT National Transportation Integrated Search

1999-11-01

This plan describes coordinated long-term research initiatives to bring about advances in aviation that will be required in the opening decades of the next century. The White House Commission on Aviation Safety and Security and the National Civil Avi...

National Research and Development Plan For Aviation Safety, Security, Efficiency, and Environmental Compatibility

DOT National Transportation Integrated Search

1999-11-01

This plan describes coordinated long-term research initiatives to bring about advances in aviation that will be required in the opening decades of the next century. The White House Commission on Aviation Safety and Security and the National Civil Avi...

Short-term static corrosion tests in lead-bismuth

NASA Astrophysics Data System (ADS)

Soler Crespo, L.; Martín Muñoz, F. J.; Gómez Briceño, D.

2001-07-01

Martensitic steels have been proposed to be used as structural materials and as spallation target window in hybrid systems devoted to the transmutation of radioactive waste of long life and high activity. However, their compatibility with lead-bismuth in the operating conditions of these systems depends on the existence of a protective layer such as an oxide film. The feasibility of forming and maintaining an oxide layer or maintaining a pre-oxidised one has been studied. Martensitic steel F82Hmod. (8% Cr) has been tested in lead-bismuth under static and isothermal conditions at 400°C and 600°C. In order to study the first stages of the interaction between the steel and the eutectic, short-term tests (100 and 665 h) have been carried out. Pre-oxidised and as-received samples have been tested in atmospheres with different oxidant potential. For low oxygen concentration in lead-bismuth due to unexpected oxygen consumption in the experimental device, dissolution of as-received F82Hmod. occurs and pre-oxidation does not prevent the material dissolution. For high oxygen concentration, the pre-oxidation layer seems to improve the feasibility of protecting stainless steels controlling the oxygen potential of lead-bismuth with a gas phase.

Reactivity Studies of Inconel 625 with Sodium, and Lunar Regolith Stimulant

NASA Technical Reports Server (NTRS)

Gillies, Donald; Salvail, Pat; Reid, Bob; Colebaugh, James; Easterling, Greg

2008-01-01

In the event of the need for nuclear power in exploration, high flux heat pipes will be needed for heat transfer from space nuclear reactors to various energy conversion devices, and to safely dissipate excess heat. Successful habitation will necessitate continuous operation of alkali metal filled heat pipes for 10 or-more years in a hostile environment with little maintenance. They must be chemical and creep resistant in the high vacuum of space (lunar), and they must operate reliably in low gravity conditions with intermittent high radiation fluxes. One candidate material for the heat pipe shell, namely Inconel 625, has been tested to determine its compatibility with liquid sodium. Any reactivity could manifest itself as a problem over the long time periods anticipated. In addition, possible reactions with the lunar regolith will take place, as will evaporation of selected elements at the external surfaces of the heat pipes, and so there is a need for extensive long-term testing under simulated lunar conditions.

Characterizing the γ-ray long-term variability of PKS 2155-304 with H.E.S.S. and Fermi-LAT

NASA Astrophysics Data System (ADS)

H.E.S.S. Collaboration; Abdalla, H.; Abramowski, A.; Aharonian, F.; Ait Benkhali, F.; Akhperjanian, A. G.; Andersson, T.; Angüner, E. O.; Arrieta, M.; Aubert, P.; Backes, M.; Balzer, A.; Barnard, M.; Becherini, Y.; Becker Tjus, J.; Berge, D.; Bernhard, S.; Bernlöhr, K.; Blackwell, R.; Böttcher, M.; Boisson, C.; Bolmont, J.; Bordas, P.; Bregeon, J.; Brun, F.; Brun, P.; Bryan, M.; Bulik, T.; Capasso, M.; Carr, J.; Casanova, S.; Cerruti, M.; Chakraborty, N.; Chalme-Calvet, R.; Chaves, R. C. G.; Chen, A.; Chevalier, J.; Chrétien, M.; Colafrancesco, S.; Cologna, G.; Condon, B.; Conrad, J.; Cui, Y.; Davids, I. D.; Decock, J.; Degrange, B.; Deil, C.; Devin, J.; deWilt, P.; Dirson, L.; Djannati-Ataï, A.; Domainko, W.; Donath, A.; Drury, L. O.'C.; Dubus, G.; Dutson, K.; Dyks, J.; Edwards, T.; Egberts, K.; Eger, P.; Ernenwein, J.-P.; Eschbach, S.; Farnier, C.; Fegan, S.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Förster, A.; Funk, S.; Füßling, M.; Gabici, S.; Gajdus, M.; Gallant, Y. A.; Garrigoux, T.; Giavitto, G.; Giebels, B.; Glicenstein, J. F.; Gottschall, D.; Goyal, A.; Grondin, M.-H.; Hadasch, D.; Hahn, J.; Haupt, M.; Hawkes, J.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hervet, O.; Hinton, J. A.; Hofmann, W.; Hoischen, C.; Holler, M.; Horns, D.; Ivascenko, A.; Jacholkowska, A.; Jamrozy, M.; Janiak, M.; Jankowsky, D.; Jankowsky, F.; Jingo, M.; Jogler, T.; Jouvin, L.; Jung-Richardt, I.; Kastendieck, M. A.; Katarzyński, K.; Katz, U.; Kerszberg, D.; Khélifi, B.; Kieffer, M.; King, J.; Klepser, S.; Klochkov, D.; Kluźniak, W.; Kolitzus, D.; Komin, Nu.; Kosack, K.; Krakau, S.; Kraus, M.; Krayzel, F.; Krüger, P. P.; Laffon, H.; Lamanna, G.; Lau, J.; Lees, J.-P.; Lefaucheur, J.; Lefranc, V.; Lemière, A.; Lemoine-Goumard, M.; Lenain, J.-P.; Leser, E.; Lohse, T.; Lorentz, M.; Liu, R.; López-Coto, R.; Lypova, I.; Marandon, V.; Marcowith, A.; Mariaud, C.; Marx, R.; Maurin, G.; Maxted, N.; Mayer, M.; Meintjes, P. J.; Meyer, M.; Mitchell, A. M. W.; Moderski, R.; Mohamed, M.; Mohrmann, L.; Morå, K.; Moulin, E.; Murach, T.; de Naurois, M.; Niederwanger, F.; Niemiec, J.; Oakes, L.; O'Brien, P.; Odaka, H.; Öttl, S.; Ohm, S.; Ostrowski, M.; Oya, I.; Padovani, M.; Panter, M.; Parsons, R. D.; Pekeur, N. W.; Pelletier, G.; Perennes, C.; Petrucci, P.-O.; Peyaud, B.; Piel, Q.; Pita, S.; Poon, H.; Prokhorov, D.; Prokoph, H.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raab, S.; Reimer, A.; Reimer, O.; Renaud, M.; de los Reyes, R.; Rieger, F.; Romoli, C.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Sahakian, V.; Salek, D.; Sanchez, D. A.; Santangelo, A.; Sasaki, M.; Schlickeiser, R.; Schüssler, F.; Schulz, A.; Schwanke, U.; Schwemmer, S.; Settimo, M.; Seyffert, A. S.; Shafi, N.; Shilon, I.; Simoni, R.; Sol, H.; Spanier, F.; Spengler, G.; Spies, F.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Stycz, K.; Sushch, I.; Tavernet, J.-P.; Tavernier, T.; Taylor, A. M.; Terrier, R.; Tibaldo, L.; Tiziani, D.; Tluczykont, M.; Trichard, C.; Tuffs, R.; Uchiyama, Y.; van der Walt, D. J.; van Eldik, C.; van Rensburg, C.; van Soelen, B.; Vasileiadis, G.; Veh, J.; Venter, C.; Viana, A.; Vincent, P.; Vink, J.; Voisin, F.; Völk, H. J.; Vuillaume, T.; Wadiasingh, Z.; Wagner, S. J.; Wagner, P.; Wagner, R. M.; White, R.; Wierzcholska, A.; Willmann, P.; Wörnlein, A.; Wouters, D.; Yang, R.; Zabalza, V.; Zaborov, D.; Zacharias, M.; Zdziarski, A. A.; Zech, A.; Zefi, F.; Ziegler, A.; Żywucka, N.

2017-02-01

Studying the temporal variability of BL Lac objects at the highest energies provides unique insights into the extreme physical processes occurring in relativistic jets and in the vicinity of super-massive black holes. To this end, the long-term variability of the BL Lac object PKS 2155-304 is analyzed in the high (HE, 100 MeV < E < 300 GeV) and very high energy (VHE, E > 200 GeV) γ-ray domain. Over the course of 9 yr of H.E.S.S. observations the VHE light curve in the quiescent state is consistent with a log-normal behavior. The VHE variability in this state is well described by flicker noise (power-spectral-density index ) on timescales larger than one day. An analysis of 5.5 yr of HE Fermi-LAT data gives consistent results (, on timescales larger than 10 days) compatible with the VHE findings. The HE and VHE power spectral densities show a scale invariance across the probed time ranges. A direct linear correlation between the VHE and HE fluxes could neither be excluded nor firmly established. These long-term-variability properties are discussed and compared to the red noise behavior (β 2) seen on shorter timescales during VHE-flaring states. The difference in power spectral noise behavior at VHE energies during quiescent and flaring states provides evidence that these states are influenced by different physical processes, while the compatibility of the HE and VHE long-term results is suggestive of a common physical link as it might be introduced by an underlying jet-disk connection.

An Efficient Amphiphilic-Type Triphenylamine-Based Organic Hole Transport Material for High-Performance and Ambient-Stable Dopant-Free Perovskite and Organic Solar Cells.

PubMed

Reddy, Saripally Sudhaker; Park, Ho-Yeol; Kwon, Haeun; Shin, Jongmoon; Kim, Chang-Su; Song, Myungkwan; Jin, Sung-Ho

2018-04-25

A new set of simply structured triphenylamine-based small molecules are synthesized and evaluated as dopant-free hole transporting materials (HTMs) for high-performance perovskite solar cells (PSCs) and bulk heterojunction inverted organic solar cells (BHJ IOSCs). Surprisingly, the new amphiphilic-type HTM-1 (with internal hydrophilic groups and peripheral hydrophobic alkyl tails) showed better compatibility and performance than the actual target molecule, that is, HTM-2 in PSCs and BHJ IOSCs. Importantly, the HTM-1-based dopant-free PSCs and BHJ IOSCs exhibited high power conversion efficiencies (PCEs) of 11.45 % and 8.34 %, respectively. These performances are superior and comparable to those of standard HTMs Spiro-OMeTAD (2,2',7,7'-tetrakis(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene) and PEDOT:PSS (poly(3,4-ethylenedioxythiophene)/polystyrene sulfonate) in PSCs and BHJ IOSCs, respectively. The enhanced device performance of the HTM-1-based PSCs is ascribed to its strong affinity towards the perovskite, properly aligned energy levels with respect to the perovskite valence band, and excellent hole transporting behavior. In addition, the well-organized energy levels of the HTMs showed excellent compatibility in BHJ IOSCs. The new amphiphilic-type HTM-based photovoltaic devices also showed long-term air stability over 700 h. These promising results offer new and unexpected prospects for engineering the interface between the photoactive material and HTMs in PSCs and BHJ IOSCs. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Compatability of dispersion-strengthened platinum with resistojet propellants

NASA Technical Reports Server (NTRS)

Whalen, Margaret V.; Nathal, Michael V.

1987-01-01

Resistojets for the Space Station require long life and multipropellant capability. The choice of available materials to meet these requirements is limited. Dispersion-strengthened platinum was selected. Past results indicated that it should be suffieiently inert in candidate propellant environments and should be capable of operating at moderate temperatures for extended periods. A series of propellant compatibility tests was done with platinum strengthened with either yttria or zirconia. Data presented included the results of 1000-hr tests in CO2, H2, ammonia (NH3), N2, steam, hydrazine (N2H4), and methane (CH4); and 2000-hr tests in H2 and NH3. The platinum samples were tested at 1400 C in CO2, H2, NH3, N2, steam, and N2H4; at 500 C in CH4; and at 800 C in N2H4. The mass-loss results indicated material life, exptrapolated from experimental mass-loss data, in excess of 100 000 hr in all environments except steam and N2H4, where it was greater than or =45000 hr. Generally, on the basis of mass loss, there were no compatibility concerns in any of the environments considered. Optical and scanning electron microscopy were used to determine the effect of propellants on the material surface and to evaluate material stability.

Crew Exploration Vehicle Potable Water System Verification Description

NASA Technical Reports Server (NTRS)

Tuan, George; Peterson, Laurie J.; Vega, Leticia M.

2010-01-01

A stored water system on the crew exploration vehicle (CEV) will supply the crew with potable water for: drinking and food rehydration, hygiene, medical needs, sublimation, and various contingency situations. The current baseline biocide for the stored water system is ionic silver, similar in composition to the biocide used to maintain the quality of the water, transferred from the orbiter to the International Space Station, stored in contingency water containers. In the CEV water system, a depletion of the ionic silver biocide is expected due to ionic silver-plating onto the surfaces of materials within the CEV water system, thus negating its effectiveness as a biocide. Because this may be the first time NASA is considering a stored water system for long-term missions that do not maintain a residual biocide, a team of experts in materials compatibility, biofilms and point-of-use filters, surface treatment and coatings, and biocides has been created to pinpoint concerns and perform the testing that will help alleviate concerns related to the CEV water system.

Durability of symmetric-structured metal-supported solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Tucker, Michael C.

2017-11-01

Symmetric-structure metal-supported solid oxide fuel cells (MS-SOFC) with YSZ electrolyte are fabricated with porous YSZ backbone electrodes, stainless steel supports, and infiltrated catalysts on both anode and cathode side. Durability towards aggressive thermal and redox cycling, and long-term operation is assessed. Many sealing material candidates are screened for compatibility with the cell materials and operating conditions, and a commercial sealing glass, GM31107, is selected. LSM/SDCN cells are then subjected to 200 very fast thermal cycles and 20 complete redox cycles, with minimal impact to cell performance. LSM/SDCN and SDCN/SDCN cells are operated for more than 1200 h at 700 °C. The seal and cell hermeticity is maintained, and cell ohmic impedance does not change significantly during operation. Electrode polarization increases during operation, leading to significant degradation of the cell performance. In-operando EIS and post-mortem SEM/EDS analysis suggest that catalyst coarsening and cathode Cr deposition are the dominant degradation modes.

Long-term pavement performance project laboratory materials testing and handling guide

DOT National Transportation Integrated Search

2007-09-01

The Long Term Pavement Performance (LTPP) Laboratory Material Testing Guide was originally prepared for laboratory material handling and testing of material specimens and samples of asphalt materials, portland cement concrete, aggregates, and soils u...

High-Temperature Storage Testing of ACF Attached Sensor Structures

PubMed Central

Lahokallio, Sanna; Hoikkanen, Maija; Vuorinen, Jyrki; Frisk, Laura

2015-01-01

Several electronic applications must withstand elevated temperatures during their lifetime. Materials and packages for use in high temperatures have been designed, but they are often very expensive, have limited compatibility with materials, structures, and processing techniques, and are less readily available than traditional materials. Thus, there is an increasing interest in using low-cost polymer materials in high temperature applications. This paper studies the performance and reliability of sensor structures attached with anisotropically conductive adhesive film (ACF) on two different organic printed circuit board (PCB) materials: FR-4 and Rogers. The test samples were aged at 200 °C and 240 °C and monitored electrically during the test. Material characterization techniques were also used to analyze the behavior of the materials. Rogers PCB was observed to be more stable at high temperatures in spite of degradation observed, especially during the first 120 h of aging. The electrical reliability was very good with Rogers. At 200 °C, the failures occurred after 2000 h of testing, and even at 240 °C the interconnections were functional for 400 h. The study indicates that, even though these ACFs were not designed for use in high temperatures, with stable PCB material they are promising interconnection materials at elevated temperatures, especially at 200 °C. However, the fragility of the structure due to material degradation may cause reliability problems in long-term high temperature exposure. PMID:28793735

Design, fabrication, test, and evaluation of a prototype 150-foot long composite wind turbine blade

NASA Technical Reports Server (NTRS)

Gewehr, H. W.

1979-01-01

The design, fabrication, testing, and evaluation of a prototype 150 foot long composite wind turbine blade is described. The design approach and material selection, compatible with low cost fabrication methods and objectives, are highlighted. The operating characteristics of the blade during rotating and nonrotating conditions are presented. The tensile, compression, and shear properties of the blade are reported. The blade fabrication, tooling, and quality assurance are discussed.

Packaging Technology for SiC High Temperature Electronics

NASA Technical Reports Server (NTRS)

Chen, Liang-Yu; Neudeck, Philip G.; Spry, David J.; Meredith, Roger D.; Nakley, Leah M.; Beheim, Glenn M.; Hunter, Gary W.

2017-01-01

High-temperature environment operable sensors and electronics are required for long-term exploration of Venus and distributed control of next generation aeronautical engines. Various silicon carbide (SiC) high temperature sensors, actuators, and electronics have been demonstrated at and above 500 C. A compatible packaging system is essential for long-term testing and application of high temperature electronics and sensors in relevant environments. This talk will discuss a ceramic packaging system developed for high temperature electronics, and related testing results of SiC integrated circuits at 500 C facilitated by this high temperature packaging system, including the most recent progress.

A Preliminary Research Plan for Development of a Photosynthetic Link in a Closed Ecological Life Support System

NASA Technical Reports Server (NTRS)

Morgan, P. W.

1979-01-01

The use of higher plants in a closed ecological life support system for long duration space missions involving large numbers of people is considered. The approach to planning and developing both the habitat for a long term space mission and closed ecological life support systems are discussed with emphasis on environmental compatibility and integrated systems design. The requirements of photosynthetic processes are summarized and evaluated in terms of their availability within a closed ecological life support environment. Specific references are recommended as a data base for future research on this topic.

Development of Stable Liquid Glucagon Formulations for Use in Artificial Pancreas

PubMed Central

Li, Ming; Krasner, Alan; De Souza, Errol

2014-01-01

Background: A promising approach to treat diabetes is the development of fully automated artificial/bionic pancreas systems that use both insulin and glucagon to maintain euglycemia. A physically and chemically stable liquid formulation of glucagon does not currently exist. Our goal is to develop a glucagon formulation that is stable as a clear and gel-free solution, free of fibrils and that has the requisite long-term shelf life for storage in the supply chain, short-term stability for at least 7 days at 37°C, and pump compatibility for use in a bihormonal pump. Methods: We report the development of two distinct families of stable liquid glucagon formulations which utilize surfactant or surfactant-like excipients (LMPC and DDM) to “immobilize” the glucagon in solution potentially through the formation of micelles and prevention of interaction between glucagon molecules. Results: Data are presented that demonstrate long-term physical and chemical stability (~2 years) at 5°C, short-term stability (up to 1 month) under accelerated 37°C testing conditions, pump compatibility for up to 9 days, and adequate glucose responses in dogs and diabetic swine. Conclusions: These stable glucagon formulations show utility and promise for further development in artificial pancreas systems. PMID:25352634

Analysis of metallic traces from the biodegradation of endomedullary AZ31 alloy temporary implants in rat organs after long implantation times.

PubMed

Bodelón, O G; Iglesias, C; Garrido, J; Clemente, C; Garcia-Alonso, M C; Escudero, M L

2015-08-04

AZ31 alloy has been tested as a biodegradable material in the form of endomedullary implants in female Wistar rat femurs. In order to evaluate the accumulation of potentially toxic elements from the biodegradation of the implant, magnesium (Mg), aluminium (Al), zinc (Zn), manganese (Mn) and fluorine (F) levels have been measured in different organs such as kidneys, liver, lungs, spleen and brain. Several factors that may influence accumulation have been taken into account: how long the implant has been in place, whether or not the bone is fractured, and the presence of an MgF2 protective coating on the implant. The main conclusions and the clinical relevance of the study have been that AZ31 endomedullary implants have a degradation rate of about 60% after 13 months, which is fully compatible with fracture consolidation. Neither bone fracture nor an MgF2 coating seems to influence the accumulation of trace elements in the studied organs. Aluminium is the only alloying element in this study that requires special attention. The increase in Al recovered from the sampled organs represents 3.95% of the amount contained in the AZ31 implant. Al accumulates in a statistically significant way in all the organs except the brain. All of this suggests that in long-term tests AZ31 may be a suitable material for osteosynthesis.

Bonding Lexan and sapphire to form high-pressure, flame-resistant window

NASA Technical Reports Server (NTRS)

Richardson, William R.; Walker, Ernie D.

1987-01-01

Flammable materials have been studied in normal gravity and microgravity for many years. Photography plays a major role in the study of the combustion process giving a permanent visual record that can be analyzed. When these studies are extended to manned spacecraft, safety becomes a primary concern. The need for a high-pressure, flame-resistant, shatter-resistant window permitting photographic recording of combustion experiments in manned spacecraft prompted the development of a method for bonding Lexan and sapphire. Materials that resist shattering (e.g., Lexan) are not compatible with combustion experiments; the material loses strength at combustion temperatures. Sapphire is compatible with combustion temperatures in oxygen-enriched atmospheres but is subject to shattering. Combining the two materials results in a shatter-resistant, flame-resistant window. Combustion in microgravity produces a low-visibility flame; however, flame propagation and flame characteristics are readily visible as long as there is no deterioration of the image. Since an air gap between the Lexan and the sapphire would reduce transmission, a method was developed for bonding these unlike materials to minimize light loss.

Materials technology for an advanced space power nuclear reactor concept: Program summary

NASA Technical Reports Server (NTRS)

Gluyas, R. E.; Watson, G. K.

1975-01-01

The results of a materials technology program for a long-life (50,000 hr), high-temperature (950 C coolant outlet), lithium-cooled, nuclear space power reactor concept are reviewed and discussed. Fabrication methods and compatibility and property data were developed for candidate materials for fuel pins and, to a lesser extent, for potential control systems, reflectors, reactor vessel and piping, and other reactor structural materials. The effects of selected materials variables on fuel pin irradiation performance were determined. The most promising materials for fuel pins were found to be 85 percent dense uranium mononitride (UN) fuel clad with tungsten-lined T-111 (Ta-8W-2Hf).

Comparison of thermal compatibility between atomized and comminuted U{sub 3}Si dispersion fuels

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

Ryu, Woo-Seog; Park, Jong-Man; Kim, Chang-Kyu

1997-08-01

Thermal compatibility of atomized U{sub 3}Si dispersion fuels were evaluated up to 2600 hours in the temperature range from 250 to 500{degrees}C, and compared with that of comminuted U{sub 3}Si. Atomized U{sub 3}Si showed better performance in terms of volume expansion of fuel meats. The reaction zone of U{sub 3}Si and Al occurred along the grain boundaries and deformation bands in U{sub 3}Si particles. Pores around fuel particles appeared at high temperature or after long-term annealing tests to remain diffusion paths over the trench of the pores. The constraint effects of cladding on fuel rod suppressed the fuel meat, andmore » reduced the volume expansion.« less

Interface Reactions and Synthetic Reaction of Composite Systems

PubMed Central

Park, Joon Sik; Kim, Jeong Min

2010-01-01

Interface reactions in composite systems often determine their overall properties, since product phases usually formed at interfaces during composite fabrication processing make up a large portion of the composites. Since most composite materials represent a ternary or higher order materials system, many studies have focused on analyses of diffusion phenomena and kinetics in multicomponent systems. However, the understanding of the kinetic behavior increases the complexity, since the kinetics of each component during interdiffusion reactions need to be defined for interpreting composite behaviors. From this standpoint, it is important to clarify the interface reactions for producing compatible interfaces with desired product phases. A thermodynamic evaluation such as a chemical potential of involving components can provide an understanding of the diffusion reactions, which govern diffusion pathways and product phase formation. A strategic approach for designing compatible interfaces is discussed in terms of chemical potential diagrams and interface morphology, with some material examples.

A disposable flexible humidity sensor directly printed on paper for medical applications

NASA Astrophysics Data System (ADS)

Barmpakos, D.; Segkos, A.; Tsamis, C.; Kaltsas, G.

2017-11-01

The present study demonstrates an inkjet - printed interdigitated electrode array on paper substrate and its evaluation as humidity sensor. Inkjet droplet formation analysis has been performed in order to achieve repeatable results regarding generated droplets, based on the driving pulses applied on the inkjet piezoelectric element. Droplet formation has been monitored using stroboscopic effect. Three different paper substrates, namely high glossy inkjet photo paper, glossy inkjet photo and matte inkjet photo paper have been evaluated to investigate compatibility with the ink. Relative humidity measurements have been carried out in a controlled environment. Material degradation, long term response and memory effect are some of the aspects which were studied within the frame of the present work. The proposed sensor provides the opportunity for novel biomedical applications given the flexible substrate nature and the low - cost, single - step fabrication approach.

Long term storage test of titanium material with liquid fluorine propellant

NASA Technical Reports Server (NTRS)

Denson, J. R.; English, W. D.; Roth, J.; Toy, A.

1979-01-01

The compatibility of 6AL-4V Ti with propellant grade GF2 and LF2 at 77 K for up to 3 years was investigated. Titanium double coupons, annealed or heat treated, with 16 or 64 RMS finishes, were immersed in F2 in individual Pyrex capsules and stored under LN2 for 29 and 39 months. Pre and post immersion tests were performed on the propellant and coupons. Chemical analysis of the propellant did not reveal any significant changes due to titanium corrosion. Gravimetric, visual, microscopic, and metallurgical examination with pitting analysis did not reveal gross corrosion of the titanium although pitting appears to be greater after 39 months exposure. The increase in pit size and number raises the possibility of unpredictable crack propagation instability. Fracture toughness tests are necessary to define this possibility.

The effect of coimmobilizing heparin and fibronectin on titanium on hemocompatibility and endothelialization.

PubMed

Li, Guicai; Yang, Ping; Qin, Wei; Maitz, Manfred F; Zhou, Shuo; Huang, Nan

2011-07-01

Currently available cardiovascular implants, such as heart valves and stents, exhibit suboptimal biocompatibility because of the incomplete endothelialization and sequential thrombosis formation especially after a long-term implantation. To improve the blood compatibility and endothelialization simultaneously and ensure the long-term effect of the cardiovascular implants, a technique of combining electrostatic interaction and coimmobilization was developed to form heparin and fibronectin (Hep/Fn) films on aminosilanized titanium (Ti) surfaces. The Hep/Fn coimmobilized films were stable after immersion in PBS for five days, probed by wettability studies and by the release kinetics of heparin and fibronectin. Blood compatibility tests showed that the coimmobilized Hep/Fn films displayed lower hemolysis rate, prolonged blood coagulation time, higher AT III binding density, less platelets activation and aggregation, and less fibrinogen conformational change compared with Ti surface. Endothelial cells (ECs) seeding and fibronectin bioactivity results showed more attached and proliferated ECs and exposed cell-binding sites on the Hep/Fn immobilized samples than that on Ti surfaces. Thus, the Hep/Fn coimmobilized films kept excellent bioactivity even after immersion in PBS for five days. Systemic evaluation suggests that the coimmobilization of Hep/Fn complex improves the blood compatibility and promotes the endothelialization simultaneously. We envisage that this method will provide a potential and effective selection for biomaterials surface modification of cardiovascular implants. Copyright © 2011 Elsevier Ltd. All rights reserved.

Processing of fine grained AISI 304L austenitic stainless steel by cold rolling and high-temperature short-term annealing

NASA Astrophysics Data System (ADS)

Naghizadeh, Meysam; Mirzadeh, Hamed

2018-05-01

An advanced thermomechanical process based on the formation and reversion of deformation-induced martensite was used to refine the grain size and enhance the hardness of an AISI 304L austenitic stainless steel. Both low and high reversion annealing temperatures and also the repetition of the whole thermomechanical cycle were considered. While a microstructure with average austenite grain size of a few micrometers was achieved based on cold rolling and high-temperature short-term annealing, an extreme grain refinement up to submicrometer regime was obtained by cold rolling followed by low-temperature long-term annealing. However, the required annealing time was found to be much longer, which negates its appropriateness for industrial production. While a magnificent grain refinement was achieved by one pass of the high-temperature thermomechanical process, the reduction in grain size was negligible by the repetition of the whole cycle. It was found that the hardness of the thermomechanically processed material is much higher than that of the as-received material. The results of the present work were shown to be compatible with the general trend of grain size dependence of hardness for AISI 304L stainless steel based on the Hall-Petch relationship. The results were also discussed based on the X-ray evaluation of dislocation density by modified Williamson-Hall plots.

Long-time dynamic compatibility of elastomeric materials with hydrazine

NASA Technical Reports Server (NTRS)

Coulbert, C. D.; Cuddihy, E. F.; Fedors, R. F.

1973-01-01

The tensile property surfaces for two elastomeric materials, EPT-10 and AF-E-332, were generated in air and in liquid hydrazine environments using constant strain rate tensile tests over a range of temperatures and elongation rates. These results were used to predict the time-to-rupture for these materials in hydrazine as a function of temperature and amount of strain covering a span of operating times from less than a minute to twenty years. The results of limited sheet-folding tests and their relationship to the tensile failure boundary are presented and discussed.

Investigating the micromorphological differences of the implant-abutment junction and their clinical implications: a pilot study.

PubMed

Mattheos, Nikos; Li, Xiaona; Zampelis, Antonios; Ma, Li; Janda, Martin

2016-11-01

The aim of this pilot study was to investigate the morphological micro-features of three commercially available implant-abutment joints, using compatible and original prosthetic components. Furthermore, possible correlations between the micromorphology and potential functional complications were investigated with the use of finite element analysis. Three abutments (one original and two compatibles) were torqued on original Straumann RN implants, as according to each of the manufacturer's instructions. The implant-abutment units were sliced in the microtome and photographed under different magnifications (10×-500×) through a scanning electron microscope. Finite element analysis models were reconstructed for each of the implant-abutment units using the precise measurements from the SEM. Differences in stress, strain and deformation for the three different abutments were then calculated using ANSYS Workbench v13. Major dimensional differences were identified between all studied contact areas of the three units. The tight contact in the implant shoulder was similar in all three units, but engagement of the internal connection and, in particular, the anti-rotation elements was seriously compromised in the compatible abutments. One compatible abutment demonstrated compromised engagement of the abutment screw as well. Equivalent stress and strain in the FEA were much higher for the compatible abutments. An evaluation of the sequence of preload application revealed differences in the pattern of deformation between the original and compatible abutments, which can have serious clinical implications. Compatible abutments can present critical morphological differences from the original ones. The differences in the cross-sectional geometry result in large differences in the overall contact areas, both in terms of quality and quantity which could have serious implications for the long-term stability of the prosthesis. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Development of tungsten armor and bonding to copper for plasma-interactive components

NASA Astrophysics Data System (ADS)

Smid, I.; Akiba, M.; Vieider, G.; Plöchl, L.

1998-10-01

For the highest sputtering threshold of all possible candidates, tungsten will be the most likely armor material in highly loaded plasma-interactive components of commercially relevant fusion reactors. The development of new materials, as well as joining and coating techniques are needed to find the best balance in plasma compatibility, lifetime, reliability, neutron irradiation resistance, and safety. Further important issues for selection are availability, costs of machining and production, etc. Tungsten doped with lanthanum oxide is a commercially available W grade for electrodes, designed for low electron work function, higher recrystallization temperature, reduced secondary grain growth, and machinability at relatively low costs. W-Re and related tungsten base alloys are preferred for application at high temperatures, when high strength, high thermal shock and recrystallization resistance are required. Due to the high costs and limited global availability of Re, however, the amount of such alloys in a commercial reactor should be kept low. Newly measured material properties up to high temperatures are presented for lanthanated and W-Re alloys, and the impact on fusion application is discussed. Recently developed coatings of chemical vapor deposited tungsten (CVD-W) on copper substrates have proven to be resistant to repeated thermal and shock loading. Layers of more than 5 mm, as required for the International Thermonuclear Experimental Reactor (ITER), became available. Vacuum plasma sprayed tungsten (VPS-W) in particular is attractive for its lower costs, and the potential of in situ repair. However, the advantage of sacrificial plasma-interactive tungsten coatings in long-term fusion devices has yet to be demonstrated. A durable and reliable joining of bulk tungsten to copper is needed to achieve an acceptable component lifetime in a fusion environment. The material properties of the copper alloys proposed for ITER, and their impact on the quality of bonding to tungsten is discussed. Future materials R&D should concern issues such as plasma compatibility, and above all neutron irradiation damage of promising tungsten-copper joints.

Silicon Carbide Integrated Circuit Chip

NASA Image and Video Library

2015-02-17

A multilevel interconnect silicon carbide integrated circuit chip with co-fired ceramic package and circuit board recently developed at the NASA GRC Smart Sensors and Electronics Systems Branch for high temperature applications. High temperature silicon carbide electronics and compatible packaging technologies are elements of instrumentation for aerospace engine control and long term inner-solar planet explorations.

49 CFR 39.3 - What do the terms in this rule mean?

Code of Federal Regulations, 2012 CFR

2012-10-01

...; notetakers; real-time computer-aided transcription services; written materials; exchange of written notes... compatible with hearing aids; closed caption decoders; open and closed captioning, including real-time.... 225 and 611), as it may be amended from time to time. “Assistive device” means any piece of equipment...

49 CFR 39.3 - What do the terms in this rule mean?

Code of Federal Regulations, 2013 CFR

2013-10-01

...; notetakers; real-time computer-aided transcription services; written materials; exchange of written notes... compatible with hearing aids; closed caption decoders; open and closed captioning, including real-time.... 225 and 611), as it may be amended from time to time. “Assistive device” means any piece of equipment...

A reverse KAM method to estimate unknown mutual inclinations in exoplanetary systems

NASA Astrophysics Data System (ADS)

Volpi, Mara; Locatelli, Ugo; Sansottera, Marco

2018-05-01

The inclinations of exoplanets detected via radial velocity method are essentially unknown. We aim to provide estimations of the ranges of mutual inclinations that are compatible with the long-term stability of the system. Focusing on the skeleton of an extrasolar system, i.e. considering only the two most massive planets, we study the Hamiltonian of the three-body problem after the reduction of the angular momentum. Such a Hamiltonian is expanded both in Poincaré canonical variables and in the small parameter D_2, which represents the normalised angular momentum deficit. The value of the mutual inclination is deduced from D_2 and, thanks to the use of interval arithmetic, we are able to consider open sets of initial conditions instead of single values. Looking at the convergence radius of the Kolmogorov normal form, we develop a reverse KAM approach in order to estimate the ranges of mutual inclinations that are compatible with the long-term stability in a KAM sense. Our method is successfully applied to the extrasolar systems HD 141399, HD 143761 and HD 40307.

Titanium-nitride-oxide-coated coronary stents: insights from the available evidence.

PubMed

Karjalainen, Pasi P; Nammas, Wail

2017-06-01

Coating of stent surface with a biocompatible material is suggested to improve stent safety profile. A proprietary process was developed to coat titanium-nitride-oxide on the stent surface, based on plasma technology that uses the nano-synthesis of gas and metal. Preclinical in vitro and in vivo investigation confirmed blood compatibility of titanium (nitride-) oxide films. Titanium-nitride-oxide-coated stents demonstrated a better angiographic outcome, compared with bare-metal stents at mid-term follow-up; however, they failed to achieve non-inferiority for angiographic outcome versus second-generation drug-eluting stents. Observational studies showed adequate clinical outcome at mid-term follow-up. Non-randomized studies showed an outcome of titanium-nitride-oxide-coated stents comparable to - or better than - first-generation drug-eluting stents at long-term follow-up. Two randomized controlled trials demonstrated comparable efficacy outcome, and a better safety outcome of titanium-nitride-oxide-coated stents versus drug-eluting stents at long-term follow-up. Evaluation by optical coherence tomography at mid-term follow-up revealed better neointimal strut coverage associated with titanium-nitride-oxide-coated stents versus drug-eluting stents; yet, neointimal hyperplasia thickness was greater. Key messages Stents coated with titanium-nitride-oxide demonstrated biocompatibility in preclinical studies: they inhibit platelet and fibrin deposition, and reduce neointimal growth. In observational and non-randomized studies, titanium-nitride-oxide-coated stents were associated with adequate safety and efficacy outcome. In randomized trials of patients with acute coronary syndrome, titanium-nitride-oxide-coated stents were associated with a better safety outcome, compared with drug-eluting stents; efficacy outcome was comparable.

Incorporating Graphene Oxide into Alginate Polymer with a Cationic Intermediate To Strengthen Membrane Dehydration Performance.

PubMed

Guan, Kecheng; Liang, Feng; Zhu, Haipeng; Zhao, Jing; Jin, Wanqin

2018-04-25

Two-dimensional graphene oxide (GO) in hybrid membranes provides fast water transfer across its surface due to the abundant oxygenated functional groups to afford water sorption and the hydrophobic basal plane to create fast transporting pathways. To establish more compatible and efficient interactions for GO and sodium alginate (SA) polymer chains, cations sourced from lignin are employed to decorate GO (labeled as cation-functionalized GO (CG)) nanosheets via cation-π and π-π interactions, providing more interactive sites to confer synergetic benefits with polymer matrix. Cations from CG are also functional to partially interlock SA chains and intensify water diffusion. And with the aid of two-dimensional pathways of CG, fast selective water permeation can be realized through hybrid membranes with CG fillers. In dehydrating aqueous ethanol solution, the hybrid membrane exhibits considerable performance compared with bare SA polymer membrane (long-term stable permeation flux larger than 2500 g m -2 h -1 and water content larger than 99.7 wt %, with feed water content of 10 wt % under 70 °C). The effects of CG content in SA membrane were investigated, and the transport mechanism was correspondingly studied through varying operation conditions and membrane materials. In addition, such a membrane possesses long-term stability and almost unchanged high dehydration capability.

Thermodynamic analysis of chemical compatibility of several reinforcement materials with niobium aluminides

NASA Technical Reports Server (NTRS)

Misra, Ajay K.

1989-01-01

Chemical compatibility of several reinforcement materials with three niobium aluminides, Nb3Al, Nb2Al, and NbAl3, were examined from thermodynamic considerations. The reinforcement materials considered in this study include carbides, borides, nitrides, oxides, silicides, and Engel-Brewer compounds. Thermodynamics of the Nb-Al system were reviewed and activities of Nb and Al were derived at desired calculation temperatures. Criteria for chemical compatibility between the reinforcement material and Nb-Al compounds have been defined and several chemically compatible reinforcement materials have been identified.

Survival and engraftment of dopaminergic neurons manufactured by a Good Manufacturing Practice-compatible process.

PubMed

Peng, Jun; Liu, Qiuyue; Rao, Mahendra S; Zeng, Xianmin

2014-09-01

We have previously reported a Good Manufacturing Practice (GMP)-compatible process for generating authentic dopaminergic neurons in defined media from human pluripotent stem cells and determined the time point at which dopaminergic precursors/neurons (day 14 after neuronal stem cell [NSC] stage) can be frozen, shipped and thawed without compromising their viability and ability to mature in vitro. One important issue we wished to address is whether dopaminergic precursors/neurons manufactured by our GMP-compatible process can be cryopreserved and engrafted in animal Parkinson disease (PD) models. In this study, we evaluated the efficacy of freshly prepared and cryopreserved dopaminergic neurons in the 6-hydroxydopamine-lesioned rat PD model. We showed functional recovery up to 6 months post-transplantation in rats transplanted with our cells, whether freshly prepared or cryopreserved. In contrast, no motor improvement was observed in two control groups receiving either medium or cells at a slightly earlier stage (day 10 after NSC stage). Histologic analysis at the end point of the study (6 months post-transplantation) showed robust long-term survival of donor-derived tyrosine hydroxylase (TH)(+) dopaminergic neurons in rats transplanted with day 14 dopaminergic neurons. Moreover, TH(+) fibers emanated from the graft core into the surrounding host striatum. Consistent with the behavioral analysis, no or few TH(+) neurons were detected in animals receiving day 10 cells, although human cells were present in the graft. Importantly, no tumors were detected in any grafted rats, but long-term tumorigenic studies will need to determine the safety of our products. Dopaminergic neurons manufactured by a GMP-compatible process from human ESC survived and engrafted efficiently in the 6-OHDA PD rat model. Copyright © 2014 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Integrating river incision rates over timescales in the Ecuadorian Andes: from uplift history to current erosion rates

NASA Astrophysics Data System (ADS)

Campforts, Benjamin; Govers, Gerard; Vanacker, Veerle; Tenorio, Gustavo

2013-04-01

River profile development is studied at different timescales, from the response to uplift over millions of years over steady state erosion rates over millennia to the response to a single event, such as a major landslide. At present, few attempts have been made to compare data obtained over various timescales. Therefore we do not know to what extent data and model results are compatible: do long-term river profile development models yield erosion rates that are compatible with information obtained over shorter time spans, both in terms of absolute rates and spatial patterns or not? Such comparisons could provide crucial insights into the nature of river development and allow us to assess the confidence we may have when predicting river response at different timescales (e.g. Kirchner et al., 2001). A major issue hampering such comparison is the uncertainty involved in the calibration of long-term river profile development models. Furthermore, calibration data on different timescales are rarely available for a specific region. In this research, we set up a river profile development model similar to the one used by Roberts & White (2010) and successfully calibrated it for the northern Ecuadorian Andes using detailed uplift and sedimentological data. Subsequently we used the calibrated model to simulate river profile development in the southern Ecuadorian Andes. The calibrated model allows to reconstruct the Andean uplift history in southern Ecuador, which is characterized by a very strong uplift phase during the last 5 My. Erosion rates derived from the modeled river incision rates were then compared with 10Be derived basin-wide erosion rates for a series of basins within the study area. We found that the model-inferred erosion rates for the last millennia are broadly compatible with the cosmogenic derived denudation rates, both in terms of absolute erosion rates as well as in terms of their spatial distribution. Hence, a relatively simple river profile development model captures the essential controls on long-term landscape development in the studied landscapes. Kirchner, J., Finkel, R., and Riebe, C., 2001, Mountain erosion over 10 yr, 10 ky, and 10 my time scales: Geology, v. 29, no. 7, p. 591-594. Roberts, G., and White, N., 2010, Estimating uplift rate histories from river profiles using African examples: Journal of Geophysical Research, v. 115, p. 1-24.

Compatibility of segmented thermoelectric generators

NASA Technical Reports Server (NTRS)

Snyder, J.; Ursell, T.

2002-01-01

It is well known that power generation efficiency improves when materials with appropriate properties are combined either in a cascaded or segmented fashion across a temperature gradient. Past methods for determining materials used in segmentation weremainly concerned with materials that have the highest figure of merit in the temperature range. However, the example of SiGe segmented with Bi2Te3 and/or various skutterudites shows a marked decline in device efficiency even though SiGe has the highest figure of merit in the temperature range. The origin of the incompatibility of SiGe with other thermoelectric materials leads to a general definition of compatibility and intrinsic efficiency. The compatibility factor derived as = (Jl+zr - 1) a is a function of only intrinsic material properties and temperature, which is represented by a ratio of current to conduction heat. For maximum efficiency the compatibility factor should not change with temperature both within a single material, and in the segmented leg as a whole. This leads to a measure of compatibility not only between segments, but also within a segment. General temperature trends show that materials are more self compatible at higher temperatures, and segmentation is more difficult across a larger -T. The compatibility factor can be used as a quantitative guide for deciding whether a material is better suited for segmentation orcascading. Analysis of compatibility factors and intrinsic efficiency for optimal segmentation are discussed, with intent to predict optimal material properties, temperature interfaces, and/or currentheat ratios.

Pore structure modified diatomite-supported PEG composites for thermal energy storage

NASA Astrophysics Data System (ADS)

Qian, Tingting; Li, Jinhong; Deng, Yong

2016-09-01

A series of novel composite phase change materials (PCMs) were tailored by blending PEG and five kinds of diatomite via a vacuum impregnation method. To enlarge its pore size and specific surface area, different modification approaches including calcination, acid treatment, alkali leaching and nano-silica decoration on the microstructure of diatomite were outlined. Among them, 8 min of 5 wt% NaOH dissolution at 70 °C has been proven to be the most effective and facile. While PEG melted during phase transformation, the maximum load of PEG could reach 70 wt.%, which was 46% higher than that of the raw diatomite. The apparent activation energy of PEG in the composite was 1031.85 kJ·mol-1, which was twice higher than that of the pristine PEG. Moreover, using the nano-silica decorated diatomite as carrier, the maximum PEG load was 66 wt%. The composite PCM was stable in terms of thermal and chemical manners even after 200 cycles of melting and freezing. All results indicated that the obtained composite PCMs were promising candidate materials for building applications due to its large latent heat, suitable phase change temperature, excellent chemical compatibility, improved supercooling extent, high thermal stability and long-term reliability.

Pore structure modified diatomite-supported PEG composites for thermal energy storage

PubMed Central

Qian, Tingting; Li, Jinhong; Deng, Yong

2016-01-01

A series of novel composite phase change materials (PCMs) were tailored by blending PEG and five kinds of diatomite via a vacuum impregnation method. To enlarge its pore size and specific surface area, different modification approaches including calcination, acid treatment, alkali leaching and nano-silica decoration on the microstructure of diatomite were outlined. Among them, 8 min of 5 wt% NaOH dissolution at 70 °C has been proven to be the most effective and facile. While PEG melted during phase transformation, the maximum load of PEG could reach 70 wt.%, which was 46% higher than that of the raw diatomite. The apparent activation energy of PEG in the composite was 1031.85 kJ·mol−1, which was twice higher than that of the pristine PEG. Moreover, using the nano-silica decorated diatomite as carrier, the maximum PEG load was 66 wt%. The composite PCM was stable in terms of thermal and chemical manners even after 200 cycles of melting and freezing. All results indicated that the obtained composite PCMs were promising candidate materials for building applications due to its large latent heat, suitable phase change temperature, excellent chemical compatibility, improved supercooling extent, high thermal stability and long-term reliability. PMID:27580677

Pore structure modified diatomite-supported PEG composites for thermal energy storage.

PubMed

Qian, Tingting; Li, Jinhong; Deng, Yong

2016-09-01

A series of novel composite phase change materials (PCMs) were tailored by blending PEG and five kinds of diatomite via a vacuum impregnation method. To enlarge its pore size and specific surface area, different modification approaches including calcination, acid treatment, alkali leaching and nano-silica decoration on the microstructure of diatomite were outlined. Among them, 8 min of 5 wt% NaOH dissolution at 70 °C has been proven to be the most effective and facile. While PEG melted during phase transformation, the maximum load of PEG could reach 70 wt.%, which was 46% higher than that of the raw diatomite. The apparent activation energy of PEG in the composite was 1031.85 kJ·mol(-1), which was twice higher than that of the pristine PEG. Moreover, using the nano-silica decorated diatomite as carrier, the maximum PEG load was 66 wt%. The composite PCM was stable in terms of thermal and chemical manners even after 200 cycles of melting and freezing. All results indicated that the obtained composite PCMs were promising candidate materials for building applications due to its large latent heat, suitable phase change temperature, excellent chemical compatibility, improved supercooling extent, high thermal stability and long-term reliability.

Upper-Stage Flight Experiment

NASA Technical Reports Server (NTRS)

Anderson, W. E.; Boxwell, R.; Crockett, D. V.; Ross, R.; Lewis, T.; McNeal, C.; Verdarame, K.

1999-01-01

For propulsion applications that require that the propellants are storable for long periods, have a high density impulse, and are environmentally clean and non-toxic, the best choice is a combination of high-concentration hydrogen peroxide (High Test Peroxide, or HTP) and a liquid hydrocarbon (LHC) fuel. The HTP/LHC combination is suitable for low-cost launch vehicles, space taxi and space maneuvering vehicles, and kick stages. Orbital Sciences Corporation is under contract with the NASA Marshall Space Flight Center in cooperation with the Air Force Research Lab to design, develop and demonstrate a new low-cost liquid upper stage based on HTP and JP-8. The Upper Stage Flight Experiment (USFE) focuses on key technologies necessary to demonstrate the operation of an inherently simple propulsion system with an innovative, state-of-the-art structure. Two key low-cost vehicle elements will be demonstrated - a 10,000 lbf thrust engine and an integrated composite tank structure. The suborbital flight test of the USFE is scheduled for 2001. Preceding the flight tests are two major series of ground tests at NASA Stennis Space Center and a subscale tank development program to identify compatible composite materials and to verify their compatibility over long periods of time. The ground tests include a thrust chamber development test series and an integrated stage test. This paper summarizes the results from the first phase of the thrust chamber development tests and the results to date from the tank material compatibility tests. Engine and tank configurations that meet the goals of the program are described.

Cubesat in-situ degradation detector (CIDD)

NASA Astrophysics Data System (ADS)

Rievers, Benny; Milke, Alexander; Salden, Daniel

2015-07-01

The design of the thermal control and management system (TCS) is a central task in satellite design. In order to evaluate and dimensionize the properties of the TCS, material parameters specifying the conductive and radiative properties of the different TCS components have to be known including their respective variations within the mission lifetime. In particular the thermo-optical properties of the outer surfaces including critical TCS components such as radiators and thermal insulation are subject to degradation caused by interaction with the space environment. The evaluation of these material parameters by means of ground testing is a time-consuming and expensive endeavor. Long-term in-situ measurements on board the ISS or large satellites not only realize a better implementation of the influence of the space environment but also imply high costs. Motivated by this we propose the utilization of low-cost nano-satellite systems to realize material tests within space at a considerably reduced cost. We present a nanosat-scale degradation sensor concept which realizes low power consumption and data rates compatible with nanosat boundaries at UHF radio. By means of a predefined measurement and messaging cycle temperature curves are measured and evaluated on ground to extract the change of absorptivity and emissivity over mission lifetime.

Microfabrication for Drug Delivery

PubMed Central

Koch, Brendan; Rubino, Ilaria; Quan, Fu-Shi; Yoo, Bongyoung; Choi, Hyo-Jick

2016-01-01

This review is devoted to discussing the application of microfabrication technologies to target challenges encountered in life processes by the development of drug delivery systems. Recently, microfabrication has been largely applied to solve health and pharmaceutical science issues. In particular, fabrication methods along with compatible materials have been successfully designed to produce multifunctional, highly effective drug delivery systems. Microfabrication offers unique tools that can tackle problems in this field, such as ease of mass production with high quality control and low cost, complexity of architecture design and a broad range of materials. Presented is an overview of silicon- and polymer-based fabrication methods that are key in the production of microfabricated drug delivery systems. Moreover, the efforts focused on studying the biocompatibility of materials used in microfabrication are analyzed. Finally, this review discusses representative ways microfabrication has been employed to develop systems delivering drugs through the transdermal and oral route, and to improve drug eluting implants. Additionally, microfabricated vaccine delivery systems are presented due to the great impact they can have in obtaining a cold chain-free vaccine, with long-term stability. Microfabrication will continue to offer new, alternative solutions for the development of smart, advanced drug delivery systems. PMID:28773770

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

Mancini, Alessandro; Felice, Valeria; Natali Sora, Isabella

Chemical reactivity between cathodes and electrolytes is a crucial issue for long term SOFCs stability and performances. In this study, chemical reactivity between selected cathodic materials and the ionic conducting melilite La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25} has been extensively investigated by X-ray powder diffraction in a wide temperature range (up to 1573 K). Perovskite-type La{sub 0.8}Sr{sub 0.2}MnO{sub 3−d} and La{sub 0.8}Sr{sub 0.2}Fe{sub 0.8}Cu{sub 0.2}O{sub 3−d} and K{sub 2}NiF{sub 4}-type La{sub 2}NiO{sub 4+d} were selected as cathode materials. The results of this study allow identifying the most suitable electrode material to be used in combination with the melilite-type gallate electrolyte andmore » set the basis for future work on this novel system. - Graphical abstract: Chemical reactivity between cathodes and electrolytes is a crucial issue for long term SOFCs stability and performances. In this study, chemical reactivity between selected cathodic materials and the ionic conducting melilite La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25} has been extensively investigated by means of X-ray powder diffraction. - Highlights: • Chemical compatibility between melilite-type gallate and cathodes for SOFCs up to 1573 K. • No reactivity observed between La{sub 0.8}Sr{sub 0.2}Fe{sub 0.8}Cu{sub 0.2}O{sub 3−d} and La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25}. • Reactivity observed between La{sub 0.80}Sr{sub 0.20}MnO{sub 3−d} and La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25}. • Significant reactivity observed between La{sub 2}NiO{sub 4+d} and La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25}.« less

Cardio-PACs: a new opportunity

NASA Astrophysics Data System (ADS)

Heupler, Frederick A., Jr.; Thomas, James D.; Blume, Hartwig R.; Cecil, Robert A.; Heisler, Mary

2000-05-01

It is now possible to replace film-based image management in the cardiac catheterization laboratory with a Cardiology Picture Archiving and Communication System (Cardio-PACS) based on digital imaging technology. The first step in the conversion process is installation of a digital image acquisition system that is capable of generating high-quality DICOM-compatible images. The next three steps, which are the subject of this presentation, involve image display, distribution, and storage. Clinical requirements and associated cost considerations for these three steps are listed below: Image display: (1) Image quality equal to film, with DICOM format, lossless compression, image processing, desktop PC-based with color monitor, and physician-friendly imaging software; (2) Performance specifications include: acquire 30 frames/sec; replay 15 frames/sec; access to file server 5 seconds, and to archive 5 minutes; (3) Compatibility of image file, transmission, and processing formats; (4) Image manipulation: brightness, contrast, gray scale, zoom, biplane display, and quantification; (5) User-friendly control of image review. Image distribution: (1) Standard IP-based network between cardiac catheterization laboratories, file server, long-term archive, review stations, and remote sites; (2) Non-proprietary formats; (3) Bidirectional distribution. Image storage: (1) CD-ROM vs disk vs tape; (2) Verification of data integrity; (3) User-designated storage capacity for catheterization laboratory, file server, long-term archive. Costs: (1) Image acquisition equipment, file server, long-term archive; (2) Network infrastructure; (3) Review stations and software; (4) Maintenance and administration; (5) Future upgrades and expansion; (6) Personnel.

Evaluation and prediction of long-term environmental effects on nonmetallic materials

NASA Technical Reports Server (NTRS)

1982-01-01

Changes in functional properties of a broad spectrum of nonmetallic materials as a function of environment and exposure time were evaluated. Models for predicting long-term material performance are discussed. A literature search on specific materials in the space and simulated space environment was carried out and evaluated.

What Have We Learned From Decades of CRT, And Where Do We Go From Here?

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

Burnham, A K; Souers, P C; Gagliardi, F J

2006-09-11

The Chemical Reactivity Test, or CRT, has been the workhorse for determining short-to-medium term compatibility and thermal stability for energetic materials since the mid 1960s. The concept behind the CRT is quite simple. 0.25 g of material is heated in a 17 cm{sup 3} vessel for 22 hours at 80, 100, or 120 C, and the yield of gaseous products are analyzed by gas chromatography to determine its thermal stability. The instrumentation is shown in Figure 1, and the vessel configuration is shown in Figure 2. For compatibility purposes, two materials, normally 0.25 g of each, are analyzed as amore » mixture. Recently, data from the past 4 decades have been compiled in an Excel spreadsheet and inspected for reliability and internal consistency. The resulting processed data will be added this year to the LLNL HE Reference Guide. Also recently, we have begun to assess the suitability of the CRT to answer new compatibility issues, especially in view of more modern instrumentation now available commercially. One issue that needs to be addressed is the definition of thermal stability and compatibility from the CRT. Prokosch and Garcia (and the associated MIL-STD-1751A) state that the criterion for thermal stability is a gas yield of less than 4 cm{sup 3}/g for a single material for 22 hours at 120 C. The gases from energetic materials of interest ordinarily have an average molecular weight of about 36 g/mol, so this represents decomposition of 0.5-1.0% of the sample. This is a reasonable value, and a relatively unstable energetic material such as PETN has no problem passing. PBX 9404, which yields 1.5 to 2.0 cm{sup 3}/g historically, is used as a periodic check standard. This is interesting in itself, since the nitrocellulose in the 9404 is unstable and probably has partially decomposed over the decades. However, it is not clear whether this aging of the standard would lead to more or less gas, since the initial gaseous degradation products are captured by the DPA stabilizer. Clearly this is an issue that needs reconsideration. The criterion for compatibility is less clearly correct. Although some LLNL reports say that generation of gas in excess of the materials by themselves is an indication of incompatibility, LLNL reports invariably say that materials are compatible if they generate less than 1 cm{sup 3}/g of gas. There are two problems with this criterion. First, it is not stated whether the gas yield is per gram of energetic material or mixture. Second, a material that generates >2 cm{sup 3}/g by itself could never pass the compatibility tests as stated, because even a mixture of equal masses of that material with a completely inert material would generate >1 cm{sup 3}/g of gas per mixture. Furthermore, Prokosch states that a yield equal to or less than from the materials individually means that no reaction has occurred. Clearly, less gas can not be generated unless some type of interaction has occurred. An obvious example would be mixing CaO with a CO{sub 2}-generating energetic material. In the absence of any direct action of the CaO on the energetic material, the CO{sub 2} product would be captured by the CaO, thereby decreasing the gas yield and liberating considerable heat. In a large, closed volume, this could tip the balance to thermal runaway.« less

Long-term solar UV radiation reconstructed by Artificial Neural Networks (ANN)

NASA Astrophysics Data System (ADS)

Feister, U.; Junk, J.; Woldt, M.

2008-01-01

Artificial Neural Networks (ANN) are efficient tools to derive solar UV radiation from measured meteorological parameters such as global radiation, aerosol optical depths and atmospheric column ozone. The ANN model has been tested with different combinations of data from the two sites Potsdam and Lindenberg, and used to reconstruct solar UV radiation at eight European sites by more than 100 years into the past. Annual totals of UV radiation derived from reconstructed daily UV values reflect interannual variations and long-term patterns that are compatible with variabilities and changes of measured input data, in particular global dimming by about 1980-1990, subsequent global brightening, volcanic eruption effects such as that of Mt. Pinatubo, and the long-term ozone decline since the 1970s. Patterns of annual erythemal UV radiation are very similar at sites located at latitudes close to each other, but different patterns occur between UV radiation at sites in different latitude regions.

Extended rotations and culmination age of coast douglas-fir: Old studies speak to current issues. Forest Service research paper

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

Curtis, R.O.

1995-11-01

Trends of mean annual increment and periodic annual increment were examined in 17 long-term thinning studies in Douglas-fir (Pseuditsuga menziesii var. menziesii (Mirb.) Franco) in western Washington, western Oregon, and British Columbia. Problems in evaluating growth trends and culmination ages are discussed. None of the stands had clearly reached culmination of mean annual increment, although some seemed close. The observed trends seem generally consistent with some other recent comparisons. These comparisons indicate that rotations can be considerably extended without reducing long-term timber production; value production probably would increase. A major problem in such a strategy is design of thinning regimesmore » that can maintain a reasonable level of timber flow during the transition period while producing stand conditions compatible with other management objectives. The continuing value of long-term permanent plot studies is emphasized.« less

Bioconcrete: next generation of self-healing concrete.

PubMed

Seifan, Mostafa; Samani, Ali Khajeh; Berenjian, Aydin

2016-03-01

Concrete is one of the most widely used construction materials and has a high tendency to form cracks. These cracks lead to significant reduction in concrete service life and high replacement costs. Although it is not possible to prevent crack formation, various types of techniques are in place to heal the cracks. It has been shown that some of the current concrete treatment methods such as the application of chemicals and polymers are a source of health and environmental risks, and more importantly, they are effective only in the short term. Thus, treatment methods that are environmentally friendly and long-lasting are in high demand. A microbial self-healing approach is distinguished by its potential for long-lasting, rapid and active crack repair, while also being environmentally friendly. Furthermore, the microbial self-healing approach prevails the other treatment techniques due to the efficient bonding capacity and compatibility with concrete compositions. This study provides an overview of the microbial approaches to produce calcium carbonate (CaCO3). Prospective challenges in microbial crack treatment are discussed, and recommendations are also given for areas of future research.

Compatibility approach for the improvement of oxide thermoelectric converters for industrial heat recovery applications

NASA Astrophysics Data System (ADS)

Saucke, Gesine; Populoh, Sascha; Thiel, Philipp; Xie, Wenjie; Funahashi, Ryoji; Weidenkaff, Anke

2015-07-01

New ceramic Ca3Co3.9O9+δ /CaMn0.97W0.03O3-δ thermoelectric generators with different cross section areas A p and A n of the p- and the n-type leg are fabricated, characterized, and tested at high temperatures in long-term tests. The variation of the measured power output and the efficiency with changing A p / A n ratio is discussed and compared with calculations based on the measured material properties. The highest conversion efficiencies are reached for ratios close to the one predicted by the compatibility approach, whereas an improper choice of A p / A n leads to a strong reduction of the efficiency. A volume power density of 1.4 W/cm3 and an efficiency of 1.08% are found for the most promising generator (temperature difference Δ T = 734 K and A p / A n = 1.12). The results reveal the major importance of the A p / A n ratio for the conversion efficiency and subsequently cost and weight reduction issues, both crucial for a large scale application of thermoelectric converters. Additionally, the oxide generators proved to be very reliable, as after more than 110 h of high temperature energy conversion, no degradation is observable.

Composite-Material Tanks with Chemically Resistant Liners

NASA Technical Reports Server (NTRS)

DeLay, Thomas K.

2004-01-01

Lightweight composite-material tanks with chemically resistant liners have been developed for storage of chemically reactive and/or unstable fluids . especially hydrogen peroxide. These tanks are similar, in some respects, to the ones described in gLightweight Composite-Material Tanks for Cryogenic Liquids h (MFS-31379), NASA Tech Briefs, Vol. 25, No. 1 (January, 2001), page 58; however, the present tanks are fabricated by a different procedure and they do not incorporate insulation that would be needed to prevent boil-off of cryogenic fluids. The manufacture of a tank of this type begins with the fabrication of a reusable multisegmented aluminum mandrel in the shape and size of the desired interior volume. One or more segments of the mandrel can be aluminum bosses that will be incorporated into the tank as end fittings. The mandrel is coated with a mold-release material. The mandrel is then heated to a temperature of about 400 F (approximately equal to 200 C) and coated with a thermoplastic liner material to the desired thickness [typically approxiamtely equal to 15 mils (approximately equal to 0.38 mm)] by thermal spraying. In the thermal-spraying process, the liner material in powder form is sprayed and heated to the melting temperature by a propane torch and the molten particles land on the mandrel. The sprayed liner and mandrel are allowed to cool, then the outer surface of the liner is chemically and/or mechanically etched to enhance bonding of a composite overwrap. The etched liner is wrapped with multiple layers of an epoxy resin reinforced with graphite fibers; the wrapping can be done either by manual application of epoxy-impregnated graphite cloth or by winding of epoxy-impregnated filaments. The entire assembly is heated in an autoclave to cure the epoxy. After the curing process, the multisegmented mandrel is disassembled and removed from inside, leaving the finished tank. If the tank is to be used for storing hydrogen peroxide, then the liner material should be fluorinated ethylene/propylene (FEP), and one or more FEP O ring(s) should be used in the aluminum end fitting(s). This choice of materials is dictated by experimental observations that pure aluminum and FEP are the only materials suitable for long-term storage of hydrogen peroxide and that other materials tend to catalyze the decomposition of hydrogen peroxide to oxygen and water. Other thermoplastic liner materials that are suitable for some applications include nylon 6 and polyethylene. The processing temperatures for nylon 6 are lower than those for FEP. Nylon 6 is compatible with propane, natural gas, and other petroleum-based fuels. Polyethylene is compatible with petroleum- based products and can be used for short-term storage of hydrogen peroxide.

Effect of silver-loaded PMMA on Streptococcus mutans in a drip flow reactor.

PubMed

Williams, Dustin L; Epperson, Richard Tyler; DeGrauw, Jeffery P; Nielsen, Mattias B; Taylor, Nicholas B; Jolley, Ryan D

2017-09-01

Orthodontic retention has been proposed as a life-long commitment for patients who desire to maintain straight teeth. However, the presence of foreign material increases risk of bacterial colonization and caries formation, of which Streptococcus mutans is a key contributor. Multiple studies have assessed the ability of silver to be added to base plate material and resist attachment of S. mutans. However, it does not appear that long-term washout in connection with biofilm growth under physiologically relevant conditions has been taken into consideration. In this study, silver was added to base plate material and exposed to short- or long-term washout periods. Materials were then assessed for their ability to resist biofilm formation of S. mutans using a drip flow reactor that modeled the human oral environment. Data indicated that silver was able to resist biofilm formation following short-term washout, but long-term washout periods resulted in a lack of ability to resist biofilm formation. These data will be important for future development of base plate materials to achieve long-term antimicrobial efficacy to reduce risk of caries formation and benefit patients in the long term. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2632-2639, 2017. © 2017 Wiley Periodicals, Inc.

Outcome of ABO-incompatible adult living-donor liver transplantation for patients with hepatocellular carcinoma.

PubMed

Yoon, Young-In; Song, Gi-Won; Lee, Sung-Gyu; Hwang, Shin; Kim, Ki-Hun; Kim, Seok-Hwan; Kang, Woo-Hyoung; Cho, Hwui-Dong; Jwa, Eun-Kyoung; Kwon, Jae-Hyun; Tak, Eun-Young; Kirchner, Varvara A

2018-06-01

Living-donor liver transplantation (LDLT) can simultaneously cure hepatocellular carcinoma (HCC) and underlying liver cirrhosis, improving long-term results in patients with HCC. ABO-incompatible LDLT could expand the living-donor pool, reduce waiting times for deceased-donor liver transplantation, and improve long-term survival for some patients with HCC. We retrospectively reviewed the medical records of patients undergoing LDLT for HCC from November 2008 to December 2015 at a single institution in Korea. In total, 165 patients underwent ABO-incompatible and 753 patients underwent ABO-compatible LDLT for HCC. ABO-incompatible recipients underwent desensitization to overcome the ABO blood group barrier, including pretransplant plasma exchange and rituximab administration (300-375 mg/m 2 /body surface area). We performed 1:1 propensity score matching and included 165 patients in each group. 82.4% of ABO-incompatible and 83.0% of -compatible LDLT groups had HCC within conventional Milan criteria, respectively, and 92.1% and 92.7% of patients in each group had a Child-Pugh score of A or B. ABO-incompatible and -compatible LDLT groups were followed up for 48.0 and 48.7 months, respectively, with both groups showing comparable recurrence-free survival rates (hazard ratio [HR] 1.14; 95% CI 0.68-1.90; p = 0.630) and overall patient-survival outcomes (HR 1.10; 95% CI 0.60-2.00; p = 0.763). These findings suggested that ABO-incompatible liver transplantation is a feasible option for patients with HCC, especially for those with compensated cirrhosis with HCC within conventional Milan criteria. Despite hypothetical immunological concerns that the desensitization protocol for breaking through the ABO blood group barrier might have a negative impact on the recurrence of hepatocellular carcinoma, our experience demonstrated no significant differences in the long-term overall survival and recurrence-free survival rates between patients receiving ABO-compatible or ABO-incompatible liver transplantation. In conclusion, results from our institution indicated that ABO-incompatible living-donor liver transplantation constitutes a potentially feasible option for patients with hepatocellular carcinoma, especially those with compensated cirrhosis with hepatocellular carcinoma within conventional Milan criteria. Copyright © 2018 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Science-based strategic planning for hazardous fuel treatment.

Treesearch

D.L. Peterson; M.C. Johnson

2007-01-01

A scientific foundation coupled with technical support is needed to develop long-term strategic plans for fuel and vegetation treatments on public lands. These plans are developed at several spatial scales and are typically a component of fire management plans and other types of resource management plans. Such plans need to be compatible with national, regional, and...

Method of storing radioactive wastes using modified tobermorite

DOEpatents

Komarneni, Sridhar; Roy, Della M.

1985-01-01

A new cation exchanger is a modified tobermorite containing aluminum isomorphously substituted for silicon and containing sodium or potassium. The exchanger is selective for lead, rubidium, cobalt and cadmium and is selective for cesium over calcium or sodium. The tobermorites are compatable with cement and are useful for the long-term fixation and storage of radioactive nuclear wastes.

New York - New Jersey Highlands Regional Study: 2002 Update

Treesearch

Northeastern Area State and Private Forestry

2003-01-01

Stewardship Goals For The New York - New Jersey Highlands This 2002 Update of the 1992 New York - New Jersey Highlands Regional Study embodies the following goals for the long-term stewardship of the Highlands: 1. Manage future growth that is compatible with the region's ecological constraints; 2. Maintain an adequate surface and ground water supply that...

Arbitration between controlled and impulsive choices

PubMed Central

Economides, M.; Guitart-Masip, M.; Kurth-Nelson, Z.; Dolan, R.J.

2015-01-01

The impulse to act for immediate reward often conflicts with more deliberate evaluations that support long-term benefit. The neural architecture that negotiates this conflict remains unclear. One account proposes a single neural circuit that evaluates both immediate and delayed outcomes, while another outlines separate impulsive and patient systems that compete for behavioral control. Here we designed a task in which a complex payout structure divorces the immediate value of acting from the overall long-term value, within the same outcome modality. Using model-based fMRI in humans, we demonstrate separate neural representations of immediate and long-term values, with the former tracked in the anterior caudate (AC) and the latter in the ventromedial prefrontal cortex (vmPFC). Crucially, when subjects' choices were compatible with long-run consequences, value signals in AC were down-weighted and those in vmPFC were enhanced, while the opposite occurred when choice was impulsive. Thus, our data implicate a trade-off in value representation between AC and vmPFC as underlying controlled versus impulsive choice. PMID:25573670

SNAPSHOT: A MODERN, SUSTAINABLE HOLDUP MEASUREMENT SYSTEM

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

Rowe, Nathan C; Younkin, James R; Smith, Steven E

2016-01-01

SNAPSHOT is a software platform designed to eventually replace Holdup Measurement System 4 (HMS 4), which is the current state-of-the-art for acquisition and analysis of nondestructive assay measurement data for in situ nuclear materials, holdup, in support of criticality safety and material control and accounting. HMS 4 is over 10 years old and is currently unsustainable due to hardware and software incompatibilities that have arisen from advances in detector electronics, primarily updates to multi-channel analyzers (MCAs), and both computer and handheld operating systems. SNAPSHOT is a complete redesign of HMS 4 that addresses the issue of compatibility with modern MCAsmore » and operating systems and that is designed with a flexible architecture to support long-term sustainability. It also provides an updated and more user friendly interface and is being developed under an NQA 1 software quality assurance (SQA) program to facilitate site acceptance for safety-related applications. This paper provides an overview of the SNAPSHOT project including details of the software development process, the SQA program, and the architecture designed to support sustainability.« less

Efficiency and durability of a self-cleaning coating on concrete and stones under both natural and artificial ageing trials

NASA Astrophysics Data System (ADS)

Carmona-Quiroga, P. M.; Martínez-Ramírez, S.; Viles, H. A.

2018-03-01

This study aimed to test the performance under long-term working conditions of a commercial self-cleaning coating, a water-based TiO2 sol, on three building materials important in recent and older European heritage; Portland limestone, Woodkirk sandstone and concrete. First, the compatibility of the coating (effect on petrophysical properties) with the substrates was demonstrated by examining aesthetic properties and water vapour permeability of the building materials and secondly, the self-cleaning ability of the TiO2 nanoparticles in degrading artificial stain (rhodamine B) under UV light was evaluated. Finally, the durability (lasting performance) of photocatalytic activity was assessed during one year of outdoor exposure trial and 2000 h of accelerated ageing in a chamber with UV radiation and condensation cycles. Results showed that photocatalytic activity was unaltered on concrete, whereas on sandstone, particularly after artificial ageing, it was reduced due to the removal of nanoparticles from the surface. On limestone, a decrease of TiO2 content was observed but photodegradation efficiency (ability to perform as self-cleaner) seemed not to be affected.

Cellular compatibility of highly degradable bioactive ceramics for coating of metal implants.

PubMed

Radetzki, F; Wohlrab, D; Zeh, A; Delank, K S; Mendel, T; Berger, G; Syrowatka, F; Mayr, O; Bernstein, A

2011-01-01

Resorbable ceramics can promote the bony integration of implants. Their rate of degradation should ideally be synchronized with bone regeneration. This study examined the effect of rapidly resorbable calcium phosphate ceramics 602020, GB14, 305020 on adherence, proliferation and morphology of human bone-derived cells (HBDC) in comparison to β-TCP. The in vitro cytotoxicity was determined by the microculture tetrazolium (MTT) assay. HBDC were grown on the materials for 3, 7, 11, 15 and 19 days and counted. Cell morphology, cell attachment, cell spreading and the cytoskeletal organization of HBDC cultivated on the substrates were investigated using laser scanning microscopy and environmental scanning electron microscopy. All substrates supported sufficient cellular growth for 19 days and showed no cytotoxicity. On each material an identical cell colonisation of well communicating, polygonal, vital cells with strong focal contacts was verified. HBDC showed numerous well defined stress fibres which give proof of well spread and strongly anchored cells. Porous surfaces encouraged the attachment and spreading of HBDC. Further investigations regarding long term biomaterial/cell interactions in vitro and in vivo are required to confirm the utility of the new biomaterials.

Dry-air-stable lithium silicide-lithium oxide core-shell nanoparticles as high-capacity prelithiation reagents.

PubMed

Zhao, Jie; Lu, Zhenda; Liu, Nian; Lee, Hyun-Wook; McDowell, Matthew T; Cui, Yi

2014-10-03

Rapid progress has been made in realizing battery electrode materials with high capacity and long-term cyclability in the past decade. However, low first-cycle Coulombic efficiency as a result of the formation of a solid electrolyte interphase and Li trapping at the anodes, remains unresolved. Here we report LixSi-Li2O core-shell nanoparticles as an excellent prelithiation reagent with high specific capacity to compensate the first-cycle capacity loss. These nanoparticles are produced via a one-step thermal alloying process. LixSi-Li2O core-shell nanoparticles are processible in a slurry and exhibit high capacity under dry-air conditions with the protection of a Li2O passivation shell, indicating that these nanoparticles are potentially compatible with industrial battery fabrication processes. Both Si and graphite anodes are successfully prelithiated with these nanoparticles to achieve high first-cycle Coulombic efficiencies of 94% to >100%. The LixSi-Li2O core-shell nanoparticles enable the practical implementation of high-performance electrode materials in lithium-ion batteries.

Characterizing the biocompatibility and tumor-imaging capability of Cu2S nanocrystals in vivo

NASA Astrophysics Data System (ADS)

Poulose, Aby Cheruvathoor; Veeranarayanan, Srivani; Mohamed, M. Sheikh; Sakamoto, Yasushi; Hirosawa, Narumi; Suzuki, Yuko; Zhang, Minfang; Yudasaka, Masako; Radhakrishnan, Neelima; Maekawa, Toru; Mohanan, P. V.; Sakthi Kumar, D.

2015-07-01

Multifunctional nanomaterial-based probes have had key impacts on high-resolution and high-sensitivity bioimaging and therapeutics. Typically, NIR-absorbing metal sulfide-based nanocrystals (NCs) are highly assuring due to their unique optical properties. Yet, their in vivo behavior remains undetermined, which in turn undermines their potential bioapplications. Herein, we have examined the application of PEGylated Cu2S NCs as tumor contrast optical nanoprobes as well as investigated the short- and long-term in vivo compatibility focusing on anti-oxidant defense mechanism, genetic material, immune system, and vital organs. The studies revealed an overall safe profile of the NCs with no apparent toxicity even at longer exposure periods. The acquired observations culminate into a set of primary safety data of this nanomaterial and the use of PEGylated Cu2S NCs as promising optical nanoprobes with immense futuristic bioapplications.

Thrombotic Depositions on Right Impeller of Double-Ended Centrifugal Total Artificial Heart In Vivo.

PubMed

Karimov, Jamshid H; Horvath, David J; Okano, Shinji; Goodin, Mark; Sunagawa, Gengo; Byram, Nicole; Moazami, Nader; Golding, Leonard A R; Fukamachi, Kiyotaka

2017-05-01

The development of total artificial heart devices is a complex undertaking that includes chronic biocompatibility assessment of the device. It is considered particularly important to assess whether device design and features can be compatible long term in a biological environment. As part of the development program for the Cleveland Clinic continuous-flow total artificial heart (CFTAH), we evaluated the device for signs of thrombosis and biological material deposition in four animals that had achieved the intended 14-, 30-, or 90-day durations in each respective experiment. Explanted CFTAHs were analyzed for possible clot buildup at "susceptible" areas inside the pump, particularly the right pump impeller. Depositions of various consistency and shapes were observed. We here report our findings, along with macroscopic and microscopic analysis post explant, and provide computational fluid dynamics data with its potential implications for thrombus formation. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Refractory metals for ARPS AMTEC cells

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

Svedberg, R.C.; Sievers, R.C.

1998-07-01

Alkali Metal Thermal-to-Electric Converter (AMTEC) cells for the Advanced Radioisotope Power Systems (ARPS) program are being developed with refractory metals and alloys as the basic structural materials. AMTEC cell efficiency increases with cell operating temperature. For space applications, long term reliability and high efficiency are essential and refractory metals were selected because of their high temperature strength, low vapor pressure, and compatibility with sodium. However, refractory metals are sensitive to oxygen, nitrogen and hydrogen contamination and refractory metal cells cannot be processed in air. Because of this sensitivity, new manufacturing and processing techniques are being developed. In addition to structuralmore » elements, development of other refractory metal components for the AMTEC cells, such as the artery and evaporator wicks, pinchoff tubes and feedthroughs are required. Changes in cell fabrication techniques and processing procedures being implemented to manufacture refractory metal cells are discussed.« less

Chromium fractionation and speciation in natural waters.

PubMed

Pereira, Catarinie Diniz; Techy, João Gabriel; Ganzarolli, Edgard Moreira; Quináia, Sueli Pércio

2012-05-01

It is common for leather industries to dump chromium-contaminated effluent into rivers and other bodies of water. Thus, it is crucial to know the impacts caused by this practice to the environment. A study on chromium partitioning and speciation, with determination at trace levels, was carried out in a potentially contaminated creek. Chromium fractionation and speciation was performed using a flow-injection preconcentration system and detection by flame atomic absorption spectrometry. High levels of this element were found in the particulate material (449-9320 mg kg(-1)), which indicates its compatibility with this fraction. The concentration of Cr(iii) in the water samples collected ranged from 5.2-105.2 μg L(-1). Cr(vi) was always below of the DL (0.3 μg L(-1)). Chromium accumulation observed in the sediment (873-1691 mg kg(-1)) may confirm contamination due to the long term release of contaminated effluents in the creek.

Critical neural networks with short- and long-term plasticity.

PubMed

Michiels van Kessenich, L; Luković, M; de Arcangelis, L; Herrmann, H J

2018-03-01

In recent years self organized critical neuronal models have provided insights regarding the origin of the experimentally observed avalanching behavior of neuronal systems. It has been shown that dynamical synapses, as a form of short-term plasticity, can cause critical neuronal dynamics. Whereas long-term plasticity, such as Hebbian or activity dependent plasticity, have a crucial role in shaping the network structure and endowing neural systems with learning abilities. In this work we provide a model which combines both plasticity mechanisms, acting on two different time scales. The measured avalanche statistics are compatible with experimental results for both the avalanche size and duration distribution with biologically observed percentages of inhibitory neurons. The time series of neuronal activity exhibits temporal bursts leading to 1/f decay in the power spectrum. The presence of long-term plasticity gives the system the ability to learn binary rules such as xor, providing the foundation of future research on more complicated tasks such as pattern recognition.

Critical neural networks with short- and long-term plasticity

NASA Astrophysics Data System (ADS)

Michiels van Kessenich, L.; Luković, M.; de Arcangelis, L.; Herrmann, H. J.

2018-03-01

In recent years self organized critical neuronal models have provided insights regarding the origin of the experimentally observed avalanching behavior of neuronal systems. It has been shown that dynamical synapses, as a form of short-term plasticity, can cause critical neuronal dynamics. Whereas long-term plasticity, such as Hebbian or activity dependent plasticity, have a crucial role in shaping the network structure and endowing neural systems with learning abilities. In this work we provide a model which combines both plasticity mechanisms, acting on two different time scales. The measured avalanche statistics are compatible with experimental results for both the avalanche size and duration distribution with biologically observed percentages of inhibitory neurons. The time series of neuronal activity exhibits temporal bursts leading to 1 /f decay in the power spectrum. The presence of long-term plasticity gives the system the ability to learn binary rules such as xor, providing the foundation of future research on more complicated tasks such as pattern recognition.

Synthesis of Perfluorinated Polymers

NASA Technical Reports Server (NTRS)

Rosser, R. W.; Psarras, T.

1982-01-01

Long-chain perfluoropolyethers containing functional pendent groups were investigated as possible candidates for new sealants and elastomers that function in extreme environments. Of specific interest was development of materials exhibiting high thermal and oxidative stability at temperatures around 400 degrees C, low-temperature flexibility with glass transition at about 50 degrees C, and hydrolytic stability as well as compatibility with metals and resistance to fuels.

A United States perspective on long-term management of areas contaminated with radioactive materials.

PubMed

Jones, C Rick

2004-01-01

The US has far-reaching and extensive experience in the long-term management of areas contaminated with radioactive materials. This experience base includes the Department of Energy's continued follow-up with Hiroshima and Nagasaki from the 1940s at the Radiological Effects Research Foundation in Hiroshima, Japan, the long-term management of the Marshall Islands Programme, the clean-up of the US nuclear weapons complex and the ongoing management of accident sites such as in Palomares, Spain. This paper discusses the lessons learnt and best practices gained from this far-reaching and extensive experience in the long-term management of areas contaminated with radioactive materials. Copyright 2004 Oxford University Press

Thermodynamic Analysis of Compatibility of Several Reinforcement Materials with Beta Phase NiAl Alloys

NASA Technical Reports Server (NTRS)

Misra, Ajay K.

1988-01-01

Chemical compatibility of several reinforcement materials with beta phase NiAl alloys within the concentration range 40 to 50 at. percent Al have been analyzed from thermodynamic considerations at 1373 and 1573 K. The reinforcement materials considered in this study include carbides, borides, oxides, nitrides, beryllides, and silicides. Thermodynamic data for NiAl alloys have been reviewed and activity of Ni and Al in the beta phase have been derived at 1373 and 1573 K. Criteria for chemical compatibility between the reinforcement material and the matrix have been defined and several chemically compatible reinforcement materials have been defined.

RBC aggregation based system for long-term photoplethysmography (PPG): new prospects for PPG applications

NASA Astrophysics Data System (ADS)

Shvartsman, Leonid D.; Tverskoy, Boris

2015-03-01

We present system for long-term continuous PPG monitoring, and physical model for PPG analysis. The system is based on ideology of light scattering modulated by the process of RBC aggregation. OXIRATE's system works in reflection geometry. The sensor is tiny, completely mobile phone compatible, it can be placed nearly everywhere on the body surface. These technical features allow all-night comfortable PPG monitoring that was performed and analyzed. We can define various sleep stages on the basis of different reproducible time-behavior of PPG signal. Our system of PPG monitoring was used also for reflection pulse oximetry and for extreme PPG studies, such as diving.

10 CFR 40.28 - General license for custody and long-term care of uranium or thorium byproduct materials disposal...

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false General license for custody and long-term care of uranium... long-term care of uranium or thorium byproduct materials disposal sites. (a) A general license is... in this part for uranium or thorium mill tailings sites closed under title II of the Uranium Mill...

10 CFR 40.28 - General license for custody and long-term care of uranium or thorium byproduct materials disposal...

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false General license for custody and long-term care of uranium... long-term care of uranium or thorium byproduct materials disposal sites. (a) A general license is... in this part for uranium or thorium mill tailings sites closed under title II of the Uranium Mill...

10 CFR 40.28 - General license for custody and long-term care of uranium or thorium byproduct materials disposal...

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false General license for custody and long-term care of uranium... long-term care of uranium or thorium byproduct materials disposal sites. (a) A general license is... in this part for uranium or thorium mill tailings sites closed under title II of the Uranium Mill...

10 CFR 40.28 - General license for custody and long-term care of uranium or thorium byproduct materials disposal...

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false General license for custody and long-term care of uranium... long-term care of uranium or thorium byproduct materials disposal sites. (a) A general license is... in this part for uranium or thorium mill tailings sites closed under title II of the Uranium Mill...

The impact of experimental measurement errors on long-term viscoelastic predictions. [of structural materials

NASA Technical Reports Server (NTRS)

Tuttle, M. E.; Brinson, H. F.

1986-01-01

The impact of flight error in measured viscoelastic parameters on subsequent long-term viscoelastic predictions is numerically evaluated using the Schapery nonlinear viscoelastic model. Of the seven Schapery parameters, the results indicated that long-term predictions were most sensitive to errors in the power law parameter n. Although errors in the other parameters were significant as well, errors in n dominated all other factors at long times. The process of selecting an appropriate short-term test cycle so as to insure an accurate long-term prediction was considered, and a short-term test cycle was selected using material properties typical for T300/5208 graphite-epoxy at 149 C. The process of selection is described, and its individual steps are itemized.

High-Throughput Mechanobiology Screening Platform Using Micro- and Nanotopography.

PubMed

Hu, Junqiang; Gondarenko, Alexander A; Dang, Alex P; Bashour, Keenan T; O'Connor, Roddy S; Lee, Sunwoo; Liapis, Anastasia; Ghassemi, Saba; Milone, Michael C; Sheetz, Michael P; Dustin, Michael L; Kam, Lance C; Hone, James C

2016-04-13

We herein demonstrate the first 96-well plate platform to screen effects of micro- and nanotopographies on cell growth and proliferation. Existing high-throughput platforms test a limited number of factors and are not fully compatible with multiple types of testing and assays. This platform is compatible with high-throughput liquid handling, high-resolution imaging, and all multiwell plate-based instrumentation. We use the platform to screen for topographies and drug-topography combinations that have short- and long-term effects on T cell activation and proliferation. We coated nanofabricated "trench-grid" surfaces with anti-CD3 and anti-CD28 antibodies to activate T cells and assayed for interleukin 2 (IL-2) cytokine production. IL-2 secretion was enhanced at 200 nm trench width and >2.3 μm grating pitch; however, the secretion was suppressed at 100 nm width and <0.5 μm pitch. The enhancement on 200 nm grid trench was further amplified with the addition of blebbistatin to reduce contractility. The 200 nm grid pattern was found to triple the number of T cells in long-term expansion, a result with direct clinical applicability in adoptive immunotherapy.

Short- and Long-Term Outcomes of Student Field Research Experiences in Special Populations.

PubMed

Soliman, Amr S; Chamberlain, Robert M

2016-06-01

Global health education and training of biomedical students in international and minority health research is expending through U.S. academic institutions. This study addresses the short- and long-term outcomes of an NCI-funded R25 short-term summer field research training program. This program is designed for MPH and Ph.D. students in cancer epidemiology and related disciplines, in international and minority settings (special populations) in a recent 7-year period. Positive short-term outcome of 73 students was measured as publishing a manuscript from the field research data and having a job in special populations. Positive long-term outcome was measured as having a post-doc position, being in a doctoral program, and/or employment in special populations at least 3 years from finishing the program. Significant factors associated with both short- and long-term success included resourcefulness of the student and compatibility of personalities and interests between the student and the on-campus and off-campus mentors. Short-term-success of students who conducted international filed research was associated with visits of the on-campus mentor to the field site. Short-term success was also associated with extent of mentorship in the field site and with long-term success. Future studies should investigate how field research sites could enhance careers of students, appropriateness of the sites for specific training competencies, and how to maximize the learning experience of students in international and minority research sites.

Compatibility Studies of Hydrogen Peroxide and a New Hypergolic Fuel Blend

NASA Technical Reports Server (NTRS)

Baldridge, Jennifer; Villegas, Yvonne

2002-01-01

Several preliminary materials compatibility studies have been conducted to determine the practicality of a new hypergolic fuel system. Hypergolic fuel ignites spontaneously as the oxidizer decomposes and releases energy in the presence of the fuel. The bipropellant system tested consists of high-test hydrogen peroxide (HTP) and a liquid fuel blend consisting of a hydrocarbon fuel, an ignition enhancer and a transition metal catalyst. In order for further testing of the new fuel blend to take place, some basic materials compatibility and HTP decomposition studies must be accomplished. The thermal decomposition rate of HTP was tested using gas evolution and isothermal microcalorimetry (IMC). Materials were analyzed for compatibility with hydrogen peroxide including a study of the affect welding has on stainless steel elemental composition and its relation to HTP decomposition. Compatibility studies of valve materials in the fuel blend were performed to determine the corrosion resistance of the materials.

78 FR 34310 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Queen Conch Fishery of Puerto...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-07

...NMFS proposes regulations to implement Regulatory Amendment 2 to the Fishery Management Plan (FMP) for the Queen Conch Resources of Puerto Rico and the U.S. Virgin Islands (USVI) (Regulatory Amendment 2), as prepared by the Caribbean Fishery Management Council (Council). If implemented, this rule would revise the commercial trip limit for queen conch in the Caribbean exclusive economic zone (EEZ) to be compatible with the trip limit in USVI territorial waters. The purpose of this proposed rule is to improve the compatibility of Federal and USVI territorial regulations for queen conch in order to facilitate enforcement efforts while ensuring the long-term health of the queen conch resource.

Compatibility of the Radio Frequency Mass Gauge with Graphite-Epoxy Composite Tanks

NASA Technical Reports Server (NTRS)

Zimmerli, G. A.; Mueller, C. H.

2015-01-01

The radio frequency mass gauge (RFMG) is a low-gravity propellant quantity gauge being developed at NASA for possible use in long-duration space missions utilizing cryogenic propellants. As part of the RFMG technology development process, we evaluated the compatibility of the RFMG with a graphite-epoxy composite material used to construct propellant tanks. The key material property that can affect compatibility with the RFMG is the electrical conductivity. Using samples of 8552/IM7 graphite-epoxy composite, we characterized the resistivity and reflectivity over a range of frequencies. An RF impedance analyzer was used to characterize the out-of-plane electrical properties (along the sample thickness) in the frequency range 10 to 1800 MHZ. The resistivity value at 500 MHz was 4.8 ohm-cm. Microwave waveguide measurements of samples in the range 1.7 - 2.6 GHz, performed by inserting the samples into a WR-430 waveguide, showed reflectivity values above 98%. Together, these results suggested that a tank constructed from graphite/epoxy composite would produce good quality electromagnetic tank modes, which is needed for the RFMG. This was verified by room-temperature measurements of the electromagnetic modes of a 2.4 m diameter tank constructed by Boeing from similar graphite-epoxy composite material. The quality factor Q of the tank electromagnetic modes, measured via RF reflection measurements from an antenna mounted in the tank, was typically in the range 400 less than Q less than 3000. The good quality modes observed in the tank indicate that the RFMG is compatible with graphite-epoxy tanks, and thus the RFMG could be used as a low-gravity propellant quantity gauge in such tanks filled with cryogenic propellants.

Compatibility of the Radio Frequency Mass Gauge with Composite Tanks

NASA Technical Reports Server (NTRS)

Zimmerli, Greg; Mueller, Carl

2015-01-01

The radio frequency mass gauge (RFMG) is a low-gravity propellant quantity gauge being developed at NASA for possible use in long-duration space missions utilizing cryogenic propellants. As part of the RFMG technology development process, we evaluated the compatibility of the RFMG with a graphite-epoxy composite material used to construct propellant tanks. The key material property that can affect compatibility with the RFMG is the electrical conductivity. Using samples of 8552IM7 graphite-epoxy composite, we characterized the resistivity and reflectivity over a range of frequencies. An RF impedance analyzer was used to characterize the out-of-plane electrical properties (along the sample thickness) in the frequency range 10 to 1800 MHZ. The resistivity value at 500 MHz was 4.8 ohm-cm. Microwave waveguide measurements of samples in the range 1.7 2.6 GHz, performed by inserting the samples into a WR-430 waveguide, showed reflectivity values above 98. Together, these results suggested that a tank constructed from graphite-epoxy composite would produce good quality electromagnetic tank modes, which is needed for the RFMG. This was verified by room-temperature measurements of the electromagnetic modes of a 2.4 m diameter tank constructed by Boeing from similar graphite-epoxy composite material. The quality factor Q of the tank electromagnetic modes, measured via RF reflection measurements from an antenna mounted in the tank, was typically in the range 400 Q 3000. The good quality modes observed in the tank indicate that the RFMG is compatible with graphite-epoxy tanks, and thus the RFMG could be used as a low-gravity propellant quantity gauge in such tanks filled with cryogenic propellants.

Dynamic studies of small animals with a four-color diffuse optical tomography imager

NASA Astrophysics Data System (ADS)

Schmitz, Christoph H.; Graber, Harry L.; Pei, Yaling; Farber, Mark; Stewart, Mark; Levina, Rita D.; Levin, Mikhail B.; Xu, Yong; Barbour, Randall L.

2005-09-01

We present newly developed instrumentation for full-tomographic four-wavelength, continuous wave, diffuse optical tomography (DOT) imaging on small animals. A small-animal imaging stage was constructed, from materials compatible with in-magnet studies, which offers stereotaxic fixation of the animal and precise, stable probe positioning. Instrument performance, based on calibration and phantom studies, demonstrates excellent long-term signal stability. DOT measurements of the functional rat brain response to electric paw stimulation are presented, and these demonstrate high data quality and excellent sensitivity to hemodynamic changes. A general linear model analysis on individual trials is used to localize and quantify the occurrence of functional behavior associated with the different hemoglobin state responses. Statistical evaluation of outcomes of individual trials is employed to identify significant regional response variations for different stimulation sites. Image results reveal a diffuse cortical response and a strong reaction of the thalamus, both indicative of activation of pain pathways by the stimulation. In addition, a weaker lateralized functional component is observed in the brain response, suggesting presence of motor activation. An important outcome of the experiment is that it shows that reactions to individual provocations can be monitored, without having to resort to signal averaging. Thus the described technology may be useful for studies of long-term trends in hemodynamic response, as would occur, for example, in behavioral studies involving freely moving animals.

Standardizing flow cytometric assays in long-term population-based studies

NASA Astrophysics Data System (ADS)

Melzer, Susanne; Bocsi, Jozsef; Tárnok, Attila

2015-03-01

Quantification of leukocyte subpopulations and characterization of antigen-expression pattern on the cellular surface can play an important role in diagnostics. The state of cellular immunology on the single-cell level was analyzed by polychromatic flow cytometry in a recent comparative study within the average Leipzig population (LIFE - Leipzig Research Centre for Civilization Diseases). Data of 1699 subjects were recorded over a long-time period of three years (in a total of 1126 days). To ensure compatibility of such huge data sets, quality-controls on many levels (stability of instrumentation, low intra-laboratory variance and reader independent data analysis) are essential. The LIFE study aims to analyze various cytometric pattern to reveal the relationship between the life-style, the environmental effects and the individual health. We therefore present here a multi-step quality control procedure for long-term comparative studies.

Cibachrome testing. [photographic processing and printing materials

NASA Technical Reports Server (NTRS)

Weinstein, M. S.

1974-01-01

The use of Cibachrome products as a solution to problems encountered when contact printing Kodak film type SO-397 onto Kodak Ektrachrome color reversal paper type 1993 is investigated. A roll of aerial imagery consisting of Kodak film types SO-397 and 2443 was contact printed onto Cibachrome and Kodak materials and compared in terms of color quality, resolution, cost, and compatibility with existing equipment and techniques. Objective measurements are given in terms of resolution and sensitometric response. Comparison prints and transparencies were viewed and ranked according to overall quality and aesthetic appeal. It is recommended that Cibachrome Print material be used in place of Kodak Ektachrome paper because it is more easily processed, the cost is equivalent, and it provides improved resolution, color quality, and image fade resistance.

Materials for high-density electronic packaging and interconnection

NASA Technical Reports Server (NTRS)

1990-01-01

Electronic packaging and interconnections are the elements that today limit the ultimate performance of advanced electronic systems. Materials in use today and those becoming available are critically examined to ascertain what actions are needed for U.S. industry to compete favorably in the world market for advanced electronics. Materials and processes are discussed in terms of the final properties achievable and systems design compatibility. Weak points in the domestic industrial capability, including technical, industrial philosophy, and political, are identified. Recommendations are presented for actions that could help U.S. industry regain its former leadership position in advanced semiconductor systems production.

Compatibility of Space Nuclear Power Plant Materials in an Inert He/Xe Working Gas Containing Reactive Impurities

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

MM Hall

2006-01-31

A major materials selection and qualification issue identified in the Space Materials Plan is the potential for creating materials compatibility problems by combining dissimilar reactor core, Brayton Unit and other power conversion plant materials in a recirculating, inert He/Xe gas loop containing reactive impurity gases. Reported here are results of equilibrium thermochemical analyses that address the compatibility of space nuclear power plant (SNPP) materials in high temperature impure He gas environments. These studies provide early information regarding the constraints that exist for SNPP materials selection and provide guidance for establishing test objectives and environments for SNPP materials qualification testing.

Determination of the long-term release of metal(loid)s from construction materials using DGTs.

PubMed

Schmukat, A; Duester, L; Ecker, D; Heininger, P; Ternes, T A

2013-09-15

Long-term leaching experiments are crucial to estimate the potential release of dangerous substances from construction materials. The application of Diffuse Gradients in Thin film (DGT) in static-batch experiments was tested to study the long-term release of metal(loid)s from construction materials for hydraulic engineering, for half a year. Long-term release experiments are essential to improve calculations of the life-time release for this materials. DGTs in batch experiments were found to be a space and labour efficient application, which enabled (i) to study, in a non-invasive manner, the total release of nine metal(loid)s for half a year, (ii) to differentiate between release mechanisms and (iii) to study mechanisms which were contrary to the release or caused experimental artefacts in the batch experiments. For copper slag (test material) it was found that eight metal(loid)s were released over the whole time period of 184 d. Cu, Ni and Pb were found to be released, predominantly caused by (the) weathering of sulphide minerals. Only for Zn a surface depletion mechanism was identified. The results from the long-term batch experiments deliver new information on the release of metal(loid)s during the life cycle of construction materials with regard to river basin management objectives. Copyright © 2013 Elsevier B.V. All rights reserved.

Experimental Results of an Electrostatic Injector

DTIC Science & Technology

2014-10-01

is important especially in the realm of biofuels . In the long term, the United States Department of Defense (DOD) is interested in converting many...of their vehicles to biofuels . Both the U.S. Army and Navy have invested substantially into research pertaining to converting existing fleets to... biofuel compatibility. The recent work of Owkes and Desjardins has investigated the effects of electrostatic spray with biofuels [11]. They

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

P.E.D. Morgan; R.M. Housley; J.B. Davis

A very import, extremely-long-term, use for monazite as a radwaste encapsulant has been proposed. THe use of ceramic La-monazite for sequestering actinides (isolating them from the environment), especially plutonium and some other radioactive elements )e.g., fission-product rare earths), had been especially championed by Lynn Boatner of ORNL. Monazite may be used alone or, copying its compatibility with many other minerals in nature, may be used in diverse composite combinations.

Minerals and design of new waste forms for conditioning nuclear waste

NASA Astrophysics Data System (ADS)

Montel, Jean-Marc

2011-02-01

Safe storage of radioactive waste is a major challenge for the nuclear industry. Mineralogy is a good basis for designing ceramics, which could eventually replace nuclear glasses. This requires a new storage concept: separation-conditioning. Basic rules of crystal chemistry allow one to select the most suitable structures and natural occurrences allow assessing the long-term performance of ceramics in a geological environment. Three criteria are of special interest: compatibility with geological environment, resistance to natural fluids, and effects of self-irradiation. If mineralogical information is efficient for predicting the behaviour of common, well-known minerals, such as zircon, monazite or apatite, more research is needed to rationalize the long-term behaviour of uncommon waste form analogs.

The role of biotic forces in driving macroevolution: beyond the Red Queen

PubMed Central

Voje, Kjetil L.; Holen, Øistein H.; Liow, Lee Hsiang; Stenseth, Nils Chr.

2015-01-01

A multitude of hypotheses claim that abiotic factors are the main drivers of macroevolutionary change. By contrast, Van Valen's Red Queen hypothesis is often put forward as the sole representative of the view that biotic forcing is the main evolutionary driver. This imbalance of hypotheses does not reflect our current knowledge: theoretical work demonstrates the plausibility of biotically driven long-term evolution, whereas empirical work suggests a central role for biotic forcing in macroevolution. We call for a more pluralistic view of how biotic forces may drive long-term evolution that is compatible with both phenotypic stasis in the fossil record and with non-constant extinction rates. Promising avenues of research include contrasting predictions from relevant theories within ecology and macroevolution, as well as embracing both abiotic and biotic proxies while modelling long-term evolutionary data. By fitting models describing hypotheses of biotically driven macroevolution to data, we could dissect their predictions and transcend beyond pattern description, possibly narrowing the divide between our current understanding of micro- and macroevolution. PMID:25948685

Long-term Optical Activity of the Hard X-ray Flaring Star DG CVn

NASA Astrophysics Data System (ADS)

Šimon, V.

2017-04-01

DG CVn is a young late-type star which displayed an X-ray and optical superflare in 2014. This paper presents an analysis of the long-term activity of this object in the optical band. I used the photographic data from DASCH (Digital Access to a Sky Century @ Harvard). These measurements from the years 1895-1989 cover the blue spectral region. CCD V-band ASAS data were used for several UV Cet-type stars to place the activity of DG CVn in the context of flaring stars. I show that three large brightenings (flares) of DG CVn by more than 1 mag were detected on the DASCH plates. The character of the long-term activity (regarding the histogram of brightness) of DG CVn is compatible with those of flaring stars UV Cet and V371 Ori. The flares brighter than ˜ 0.4 mag represent less than 1 percent of the observed data in all three objects

10 CFR 40.27 - General license for custody and long-term care of residual radioactive material disposal sites.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false General license for custody and long-term care of residual... residual radioactive material disposal sites. (a) A general license is issued for the custody of and long... water characterization and any necessary ground water protection activities or strategies. This...

The STRATEGY project: decision tools to aid sustainable restoration and long-term management of contaminated agricultural ecosystems.

PubMed

Howard, B J; Beresford, N A; Nisbet, A; Cox, G; Oughton, D H; Hunt, J; Alvarez, B; Andersson, K G; Liland, A; Voigt, G

2005-01-01

The STRATEGY project (Sustainable Restoration and Long-Term Management of Contaminated Rural, Urban and Industrial Ecosystems) aimed to provide a holistic decision framework for the selection of optimal restoration strategies for the long-term sustainable management of contaminated areas in Western Europe. A critical evaluation was carried out of countermeasures and waste disposal options, from which compendia of state-of-the-art restoration methods were compiled. A decision support system capable of optimising spatially varying restoration strategies, that considered the level of averted dose, costs (including those of waste disposal) and environmental side effects was developed. Appropriate methods of estimating indirect costs associated with side effects and of communicating with stakeholders were identified. The importance of stakeholder consultation at a local level and of ensuring that any response is site and scenario specific were emphasised. A value matrix approach was suggested as a method of addressing social and ethical issues within the decision-making process, and was designed to be compatible with both the countermeasure compendia and the decision support system. The applicability and usefulness of STRATEGY outputs for food production systems in the medium to long term is assessed.

Long-Term Growth of Moss in Microfluidic Devices Enables Subcellular Studies in Development.

PubMed

Bascom, Carlisle S; Wu, Shu-Zon; Nelson, Katherine; Oakey, John; Bezanilla, Magdalena

2016-09-01

Key developmental processes that occur on the subcellular and cellular level or occur in occluded tissues are difficult to access, let alone image and analyze. Recently, culturing living samples within polydimethylsiloxane (PDMS) microfluidic devices has facilitated the study of hard-to-reach developmental events. Here, we show that an early diverging land plant, Physcomitrella patens, can be continuously cultured within PDMS microfluidic chambers. Because the PDMS chambers are bonded to a coverslip, it is possible to image P. patens development at high resolution over long time periods. Using PDMS chambers, we report that wild-type protonemal tissue grows at the same rate as previously reported for growth on solid medium. Using long-term imaging, we highlight key developmental events, demonstrate compatibility with high-resolution confocal microscopy, and obtain growth rates for a slow-growing mutant. By coupling the powerful genetic tools available to P. patens with long-term growth and imaging provided by PDMS microfluidic chambers, we demonstrate the capability to study cellular and subcellular developmental events in plants directly and in real time. © 2016 American Society of Plant Biologists. All rights reserved.

A Novel MUMPs-compatible single-layer out-of-plane electrothermal actuator

NASA Astrophysics Data System (ADS)

Tang, Weider; Wu, Mingching; Ho, Yi-Ping; Yeh, Mau-Shium; Fang, Weileun

2002-11-01

Microactuator is one of the key components for the microelectromechanical systems (MEMS), and it can be categorized as out-of-plane and in-plane according to the motion types. Most of the existing out-of-plane thermal actuators are multi-layer structures. In this paper, a novel electrothermal single-layer out-of-plane actuator is provided and it characteristics and advantages of this device are stated as follows: (1) This actuator is consisted of only a single thin film material, therefore, it can prevent from delaminating after a long-term operation. Besides, owing to its symmetric geometric design, the inner-beams of this structure don"t have any current passed through them and the inner-beams also provide a geometric constraint to allow the two free ends of the structure to bend upwards symmetrically. (2) This device can be operated at a relative low voltage (<5 volt), and deflected upwards about 4 μm in the experiment test. Besides, the fabrication process is very simple and it is MUMPs(Multi-User MEMS Processes)-compatible. Presently, a prototype structure has been successfully fabricated and tested. This structure offers the potential applications in the adaptive optics systems, and Fabry-Perot filters, etc. Besides, it also provides an interface to cooperate with integrated circuits (IC) and various optical elements to construct an embedded-control optical system.

A silicon carbide array for electrocorticography and peripheral nerve recording.

PubMed

Diaz-Botia, C A; Luna, L E; Neely, R M; Chamanzar, M; Carraro, C; Carmena, J M; Sabes, P N; Maboudian, R; Maharbiz, M M

2017-10-01

Current neural probes have a limited device lifetime of a few years. Their common failure mode is the degradation of insulating films and/or the delamination of the conductor-insulator interfaces. We sought to develop a technology that does not suffer from such limitations and would be suitable for chronic applications with very long device lifetimes. We developed a fabrication method that integrates polycrystalline conductive silicon carbide with insulating silicon carbide. The technology employs amorphous silicon carbide as the insulator and conductive silicon carbide at the recording sites, resulting in a seamless transition between doped and amorphous regions of the same material, eliminating heterogeneous interfaces prone to delamination. Silicon carbide has outstanding chemical stability, is biocompatible, is an excellent molecular barrier and is compatible with standard microfabrication processes. We have fabricated silicon carbide electrode arrays using our novel fabrication method. We conducted in vivo experiments in which electrocorticography recordings from the primary visual cortex of a rat were obtained and were of similar quality to those of polymer based electrocorticography arrays. The silicon carbide electrode arrays were also used as a cuff electrode wrapped around the sciatic nerve of a rat to record the nerve response to electrical stimulation. Finally, we demonstrated the outstanding long term stability of our insulating silicon carbide films through accelerated aging tests. Clinical translation in neural engineering has been slowed in part due to the poor long term performance of current probes. Silicon carbide devices are a promising technology that may accelerate this transition by enabling truly chronic applications.

A silicon carbide array for electrocorticography and peripheral nerve recording

NASA Astrophysics Data System (ADS)

Diaz-Botia, C. A.; Luna, L. E.; Neely, R. M.; Chamanzar, M.; Carraro, C.; Carmena, J. M.; Sabes, P. N.; Maboudian, R.; Maharbiz, M. M.

2017-10-01

Objective. Current neural probes have a limited device lifetime of a few years. Their common failure mode is the degradation of insulating films and/or the delamination of the conductor-insulator interfaces. We sought to develop a technology that does not suffer from such limitations and would be suitable for chronic applications with very long device lifetimes. Approach. We developed a fabrication method that integrates polycrystalline conductive silicon carbide with insulating silicon carbide. The technology employs amorphous silicon carbide as the insulator and conductive silicon carbide at the recording sites, resulting in a seamless transition between doped and amorphous regions of the same material, eliminating heterogeneous interfaces prone to delamination. Silicon carbide has outstanding chemical stability, is biocompatible, is an excellent molecular barrier and is compatible with standard microfabrication processes. Main results. We have fabricated silicon carbide electrode arrays using our novel fabrication method. We conducted in vivo experiments in which electrocorticography recordings from the primary visual cortex of a rat were obtained and were of similar quality to those of polymer based electrocorticography arrays. The silicon carbide electrode arrays were also used as a cuff electrode wrapped around the sciatic nerve of a rat to record the nerve response to electrical stimulation. Finally, we demonstrated the outstanding long term stability of our insulating silicon carbide films through accelerated aging tests. Significance. Clinical translation in neural engineering has been slowed in part due to the poor long term performance of current probes. Silicon carbide devices are a promising technology that may accelerate this transition by enabling truly chronic applications.

GROUND WATER ISSUE: NONAQUEOUS PHASE LIQUIDS COMPATIBILITY WITH MATERIALS USED IN WELL CONSTRUCTION, SAMPLING, AND REMEDIATION.

EPA Science Inventory

This issue paper provides a comprehensive literature review regarding the compatibility of NAPLs with a wide variety of materials used at hazardous waste sites. A condensed reference table of compatibility data for 207 chemicals and 28 commonly used well construction and sampling...

A combined long-term recording system for single-unit activity and neurotransmitter efflux of a brain slice

NASA Astrophysics Data System (ADS)

Sheu, Y. H.; Young, M. S.

1998-04-01

A combined long-term measurement and recording system for neurotransmission research of brain slices is presented in this study. This system, based on the IBM PC or compatible computer, is capable of simultaneously measuring and recording both single-unit neural electropotential signals and the electrochemical signals of neurotransmitter efflux from the same neuron in a brain slice for long periods of time (time limited largely by hard disk capacity, 100 h or more not being unreasonable with contemporary hardware) using a single carbon microelectrode for both measurements. The combined long-term recording system uses a simple switching circuit to switch periodically the single microelectrode between two data acquisition subsystems, one for electrochemical data and one for electrophysiological data. The simple switching circuit separates the electrophysiological signals and electrochemical signals, overcoming the traditional interference problem caused by the two different measuring techniques. Software designed for the proposed system allows easy reconstruction of the full time course of the compressed measured data and easy, simultaneous display of both types of signals on the same time scale. On-line and recorded displays are available. Test results of a practical implementation of the proposed system verify that the combined long-term recording system meets actual requirements for electrophysiological and neurochemical research.

Amorphous selenium direct detection CMOS digital x-ray imager with 25 micron pixel pitch

NASA Astrophysics Data System (ADS)

Scott, Christopher C.; Abbaszadeh, Shiva; Ghanbarzadeh, Sina; Allan, Gary; Farrier, Michael; Cunningham, Ian A.; Karim, Karim S.

2014-03-01

We have developed a high resolution amorphous selenium (a-Se) direct detection imager using a large-area compatible back-end fabrication process on top of a CMOS active pixel sensor having 25 micron pixel pitch. Integration of a-Se with CMOS technology requires overcoming CMOS/a-Se interfacial strain, which initiates nucleation of crystalline selenium and results in high detector dark currents. A CMOS-compatible polyimide buffer layer was used to planarize the backplane and provide a low stress and thermally stable surface for a-Se. The buffer layer inhibits crystallization and provides detector stability that is not only a performance factor but also critical for favorable long term cost-benefit considerations in the application of CMOS digital x-ray imagers in medical practice. The detector structure is comprised of a polyimide (PI) buffer layer, the a-Se layer, and a gold (Au) top electrode. The PI layer is applied by spin-coating and is patterned using dry etching to open the backplane bond pads for wire bonding. Thermal evaporation is used to deposit the a-Se and Au layers, and the detector is operated in hole collection mode (i.e. a positive bias on the Au top electrode). High resolution a-Se diagnostic systems typically use 70 to 100 μm pixel pitch and have a pre-sampling modulation transfer function (MTF) that is significantly limited by the pixel aperture. Our results confirm that, for a densely integrated 25 μm pixel pitch CMOS array, the MTF approaches the fundamental material limit, i.e. where the MTF begins to be limited by the a-Se material properties and not the pixel aperture. Preliminary images demonstrating high spatial resolution have been obtained from a frst prototype imager.

Selection of an Alternate Biocide for the ISS Internal Thermal Control System Coolant, Phase 2

NASA Technical Reports Server (NTRS)

Wilson, Mark E.; Cole, Harold; Weir, Natalee; Oehler, Bill; Steele, John; Varsik, Jerry; Lukens, Clark

2004-01-01

The ISS (International Space Station) ITCS (Internal Thermal Control System) includes two internal coolant loops that utilize an aqueous based coolant for heat transfer. A silver salt biocide had previously been utilized as an additive in the coolant formulation to control the growth and proliferation of microorganisms within the coolant loops. Ground-based and in-flight testing demonstrated that the silver salt was rapidly depleted, and did not act as an effective long-term biocide. Efforts to select an optimal alternate biocide for the ITCS coolant application have been underway and are now in the final stages. An extensive evaluation of biocides was conducted to down-select to several candidates for test trials and was reported on previously. Criteria for that down-select included: the need for safe, non-intrusive implementation and operation in a functioning system; the ability to control existing planktonic and biofilm residing microorganisms; a negligible impact on system-wetted materials of construction; and a negligible reactivity with existing coolant additives. Candidate testing to provide data for the selection of an optimal alternate biocide is now in the final stages. That testing has included rapid biocide effectiveness screening using Biolog MT2 plates to determine minimum inhibitory concentration (amount that will inhibit visible growth of microorganisms), time kill studies to determine the exposure time required to completely eliminate organism growth, materials compatibility exposure evaluations, coolant compatibility studies, and bench-top simulated coolant testing. This paper reports the current status of the effort to select an alternate biocide for the ISS ITCS coolant. The results of various test results to select the optimal candidate are presented.

The effect of long-term working memory through personalization applied to free recall: uncurbing the primacy-effect enthusiasm.

PubMed

Guida, Alessandro; Gras, Doriane; Noel, Yvonnick; Le Bohec, Olivier; Quaireau, Christophe; Nicolas, Serge

2013-05-01

In this study, a personalization method (Guida, Tardieu, & Nicolas, European Journal of Cognitive Psychology, 21: 862-896 2009) was applied to a free-recall task. Fifteen pairs of words, composed of an object and a location, were presented to 93 participants, who had to mentally associate each pair and subsequently recall the objects. A 30-s delay was introduced on half of the trials, the presentation rate was manipulated (5 or 10 s per item), and verbal and visuospatial working memory tests were administered to test for their effects on the serial curve. Two groups were constituted: a personalized group, for whom the locations were well-known places on their university campus, and a nonpersonalized group, for whom the locations did not refer to known places. Since personalization putatively operationalizes long-term working memory (Ericsson & Kintsch, Psychological Review, 102: 211-245 1995)-namely, the capacity to store information reliably and rapidly in long-term memory-and if we take a dual-store approach to memory, the personalization advantage would be expected to be greater for pre-recency than for recency items. Overall, the results were compatible with long-term working memory theory. They contribute to validating the personalization method as a methodology to characterize the contribution of long-term memory storage to performance in working memory tasks.

Problems of equipment creation for hygienic treatment of textiles (underwear, garments, hygienic towels and napkins) for long-term space missions

NASA Astrophysics Data System (ADS)

Shumilina, I.

Impossibility of just in time stocks delivery to the International Space Station ISS because of Shuttle space flights absence has led to forced changing of standards of underwear garments and personal hygiene means using Therefore hygienic treatment of textiles underwear garments towels and napkins are necessary for long-term space flight missions Investigations into the ways of cosmonauts sanitary -- hygienic supply are prepared The resent equipment means and methods of cosmonauts sanitary -- hygienic supply were created for space flight conditions with an opportunity of stocks updating This investigations are confirm necessity of new generation system creation for cosmonauts sanitary -- hygienic supply and special designing of hygienic treatment laundry drying equipment and technologies for long-term space flights without an opportunity of stocks updating in particular for martian mission One from main requirements for equipment means and methods of cosmonauts sanitary -- hygienic supply is full safety for human organisms under systematic and long-term application in space flight conditions small energy consumption and combining with space Life-Support Systems Method and program of experimental investigations of textiles laundry with application of washing means for long-term space flight conditions are prepared It is necessary to estimate opportunity and efficiency of washing means application for textiles laundry for space flight missions also to estimate compatibility of washing means for textiles laundry and for washing

10 CFR 40.28 - General license for custody and long-term care of uranium or thorium byproduct materials disposal...

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false General license for custody and long-term care of uranium or thorium byproduct materials disposal sites. 40.28 Section 40.28 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF SOURCE MATERIAL General Licenses § 40.28 General license for custody and...

Chondritic late accretion to Mars and the nature of shergottite reservoirs

NASA Astrophysics Data System (ADS)

Tait, Kim T.; Day, James M. D.

2018-07-01

Mars is considered to have formed as a planetary embryo that experienced extensive differentiation early in its history. Shergottite meteorites preserve evidence for this history, and for late accretion events that affected their mantle sources within Mars. Here we report the first coupled 187Re-187Os, 87Sr/86Sr, highly siderophile element (HSE: Os, Ir, Ru, Pt, Pd, Re) and major element abundance dataset for martian shergottites that span a range of MgO contents, from 6.4 to 30.3 wt.%. The shergottites range from picro-basalt to basaltic-andesite compositions, have enriched to depleted incompatible trace-element compositions, and define fractional crystallization trends, enabling the determination of HSE compatibility for martian magmatism in the order: Os > Ir ≥ Ru ≫ Pt ≥ Pd ≥ Re. This order of compatibility is like that defined previously for Earth and the Moon, but the fractionation of strongly compatible Os, Ir and Ru appears to take place at higher MgO contents in martian magmas, due to early onset of sulfide fractionation. In general, enriched shergottites have lower MgO contents than intermediate or depleted shergottites and have fractionated HSE patterns (Re + Pd + Pt > Ru + Ir + Os) and more radiogenic measured 87Sr/86Sr (0.7127-0.7235) and 187Os/188Os (0.140-0.247) than intermediate or depleted shergottite meteorites (87Sr/86Sr = 0.7010-0.7132; 187Os/188Os = 0.127-0.141). Osmium isotope compositions, corrected for crystallization age, define compositions that are implausibly unradiogenic in some enriched shergottites, implying recent mobilization of Re in some samples. Filtering for the effects of alteration and high Re/Os through crystal-liquid fractionation leads to a positive correlation between age-corrected Sr and Os isotope compositions. Mixing between hypothetical martian crustal and mantle reservoirs are unable to generate the observed Sr-Os isotope compositions of shergottites, which require either distinct and discrete long-term incompatible-element depleted and enriched mantle sources, or originate from hybridized melting of deep melts with metasomatized martian lithosphere. Using MgO-regression methods, we obtain a modified estimate of the bulk silicate Mars HSE composition of (in ng g-1) 0.4 [Re], 7.4 [Pd], 9.6 [Pt], 6.2 [Ru], 3.7 [Ir], 4 [Os], and a long-term chondritic 187Os/188Os ratio (∼0.1312). This result does not permit existing models invoking high-pressure and temperature partitioning of the HSE. Instead, our estimate implies 0.6-0.7% by mass of late accretion of broadly chondritic material to Mars. Our results indicate that Mars could have accreted earlier than Earth, but that disproportional accretion of large bodies and a relative constant flux of accretion of available materials in the first 50-100 Ma of Solar System led to the broad similarity in HSE abundances between Earth and Mars.

Molecular cooperativity and compatibility via full atomistic simulation

NASA Astrophysics Data System (ADS)

Kwan Yang, Kenny

Civil engineering has customarily focused on problems from a large-scale perspective, encompassing structures such as bridges, dams, and infrastructure. However, present day challenges in conjunction with advances in nanotechnology have forced a re-focusing of expertise. The use of atomistic and molecular approaches to study material systems opens the door to significantly improve material properties. The understanding that material systems themselves are structures, where their assemblies can dictate design capacities and failure modes makes this problem well suited for those who possess expertise in structural engineering. At the same time, a focus has been given to the performance metrics of materials at the nanoscale, including strength, toughness, and transport properties (e.g., electrical, thermal). Little effort has been made in the systematic characterization of system compatibility -- e.g., how to make disparate material building blocks behave in unison. This research attempts to develop bottom-up molecular scale understanding of material behavior, with the global objective being the application of this understanding into material design/characterization at an ultimate functional scale. In particular, it addresses the subject of cooperativity at the nano-scale. This research aims to define the conditions which dictate when discrete molecules may behave as a single, functional unit, thereby facilitating homogenization and up-scaling approaches, setting bounds for assembly, and providing a transferable assessment tool across molecular systems. Following a macro-scale pattern where the compatibility of deformation plays a vital role in the structural design, novel geometrical cooperativity metrics based on the gyration tensor are derived with the intention to define nano-cooperativity in a generalized way. The metrics objectively describe the general size, shape and orientation of the structure. To validate the derived measures, a pair of ideal macromolecules, where the density of cross-linking dictates cooperativity, is used to gauge the effectiveness of the triumvirate of gyration metrics. The metrics are shown to identify the critical number of cross-links that allowed the pair to deform together. The next step involves looking at the cooperativity features on a real system. We investigate a representative collagen molecule (i.e., tropocollagen), where single point mutations are known to produce kinks that create local unfolding. The results indicate that the metrics are effective, serving as a validation of the cooperativity metrics in a palpable material system. Finally a preliminary study on a carbon nanotube and collagen composite is proposed with a long-term objective of understanding the interactions between them as a means to corroborate experimental efforts in reproducing a d-banded collagen fiber. The emerging needs for more robust and resilient structures, as well as sustainable are serving as motivation to think beyond the traditional design methods. The characterization of cooperativity is thus key in materiomics, an emerging field that focuses on developing a "nano-to-macro" synergistic platform, which provides the necessary tools and procedures to validate future structural models and other critical behavior in a holistic manner, from atoms to application.

25th anniversary article: progress in chemistry and applications of functional indigos for organic electronics.

PubMed

Głowacki, Eric Daniel; Voss, Gundula; Sariciftci, Niyazi Serdar

2013-12-17

Indigo and its derivatives are dyes and pigments with a long and distinguished history in organic chemistry. Recently, applications of this 'old' structure as a functional organic building block for organic electronics applications have renewed interest in these molecules and their remarkable chemical and physical properties. Natural-origin indigos have been processed in fully bio-compatible field effect transistors, operating with ambipolar mobilities up to 0.5 cm(2) /Vs and air-stability. The synthetic derivative isoindigo has emerged as one of the most successful building-blocks for semiconducting polymers for plastic solar cells with efficiencies > 5%. Another isomer of indigo, epindolidione, has also been shown to be one of the best reported organic transistor materials in terms of mobility (∼2 cm(2) /Vs) and stability. This progress report aims to review very recent applications of indigoids in organic electronics, but especially to logically bridge together the hereto independent research directions on indigo, isoindigo, and other materials inspired by historical dye chemistry: a field which was the root of the development of modern chemistry in the first place. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A novel albumin-based tissue scaffold for autogenic tissue engineering applications.

PubMed

Li, Pei-Shan; Lee, I-Liang; Yu, Wei-Lin; Sun, Jui-Sheng; Jane, Wann-Neng; Shen, Hsin-Hsin

2014-07-18

Tissue scaffolds provide a framework for living tissue regeneration. However, traditional tissue scaffolds are exogenous, composed of metals, ceramics, polymers, and animal tissues, and have a defined biocompatibility and application. This study presents a new method for obtaining a tissue scaffold from blood albumin, the major protein in mammalian blood. Human, bovine, and porcine albumin was polymerised into albumin polymers by microbial transglutaminase and was then cast by freeze-drying-based moulding to form albumin tissue scaffolds. Scanning electron microscopy and material testing analyses revealed that the albumin tissue scaffold possesses an extremely porous structure, moderate mechanical strength, and resilience. Using a culture of human mesenchymal stem cells (MSCs) as a model, we showed that MSCs can be seeded and grown in the albumin tissue scaffold. Furthermore, the albumin tissue scaffold can support the long-term osteogenic differentiation of MSCs. These results show that the albumin tissue scaffold exhibits favourable material properties and good compatibility with cells. We propose that this novel tissue scaffold can satisfy essential needs in tissue engineering as a general-purpose substrate. The use of this scaffold could lead to the development of new methods of artificial fabrication of autogenic tissue substitutes.

Aspects of bonding between resin luting cements and glass ceramic materials.

PubMed

Tian, Tian; Tsoi, James Kit-Hon; Matinlinna, Jukka P; Burrow, Michael F

2014-07-01

The bonding interface of glass ceramics and resin luting cements plays an important role in the long-term durability of ceramic restorations. The purpose of this systematic review is to discuss the various factors involved with the bond between glass ceramics and resin luting cements. An electronic Pubmed, Medline and Embase search was conducted to obtain laboratory studies on resin-ceramic bonding published in English and Chinese between 1972 and 2012. Eighty-three articles were included in this review. Various factors that have a possible impact on the bond between glass ceramics and resin cements were discussed, including ceramic type, ceramic crystal structure, resin luting cements, light curing, surface treatments, and laboratory test methodology. Resin-ceramic bonding has been improved substantially in the past few years. Hydrofluoric acid (HF) etching followed by silanizaiton has become the most widely accepted surface treatment for glass ceramics. However, further studies need to be undertaken to improve surface preparations without HF because of its toxicity. Laboratory test methods are also required to better simulate the actual oral environment for more clinically compatible testing. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Advanced Photonic Processes for Photovoltaic and Energy Storage Systems.

PubMed

Sygletou, Maria; Petridis, Constantinos; Kymakis, Emmanuel; Stratakis, Emmanuel

2017-10-01

Solar-energy harvesting through photovoltaic (PV) conversion is the most promising technology for long-term renewable energy production. At the same time, significant progress has been made in the development of energy-storage (ES) systems, which are essential components within the cycle of energy generation, transmission, and usage. Toward commercial applications, the enhancement of the performance and competitiveness of PV and ES systems requires the adoption of precise, but simple and low-cost manufacturing solutions, compatible with large-scale and high-throughput production lines. Photonic processes enable cost-efficient, noncontact, highly precise, and selective engineering of materials via photothermal, photochemical, or photophysical routes. Laser-based processes, in particular, provide access to a plethora of processing parameters that can be tuned with a remarkably high degree of precision to enable innovative processing routes that cannot be attained by conventional approaches. The focus here is on the application of advanced light-driven approaches for the fabrication, as well as the synthesis, of materials and components relevant to PV and ES systems. Besides presenting recent advances on recent achievements, the existing limitations are outlined and future possibilities and emerging prospects discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Selection of High Temperature Organic Materials for Future Stirling Convertors

NASA Technical Reports Server (NTRS)

Shin, Euy-Sik Eugene

2017-01-01

In the future higher temperature Stirling convertors for improved efficiency and performance, various high temperature organic materials have been demanded as essential components for their unique properties and functions such as bonding, potting, sealing, thread locking, insulation, and lubrication. The higher temperature capabilities would also allow current state-of-the-art (SOA) convertors to be used in additional missions, particularly those that require a Venus flyby for a gravity assist. Stirling convertor radioisotope generators have been developed for potential future space applications including Lunar/Mars surface power or a variety of spacecraft and vehicles, especially with a long mission cycle, sometimes up to 17 years, such as deep space exploration. Thus, performance, durability, and reliability of the organics should be critically evaluated in terms of comprehensive structure-process-service environment relations based on the potential mission specifications. The initial efforts in screening the high temperature candidates focused on the most susceptible organics, such as adhesive, potting compound, o-ring, shrink tubing, and thread locker materials in conjunction with commercially available materials. More systematic and practical test methodologies that were developed and optimized based on the extensive organic evaluations and validations performed for various Stirling convertor types were employed to determine thermal stability, outgassing, and material compatibility of the selected organic candidates against their functional requirements. Processing and fabrication conditions and procedures were also optimized. This paper presents results of the three-step candidate evaluation processes, their application limitations, and the final selection recommendations.

A tissue retrieval and postharvest processing regimen for rodent reproductive tissues compatible with long-term storage on the international space station and postflight biospecimen sharing program.

PubMed

Gupta, Vijayalaxmi; Holets-Bondar, Lesya; Roby, Katherine F; Enders, George; Tash, Joseph S

2015-01-01

Collection and processing of tissues to preserve space flight effects from animals after return to Earth is challenging. Specimens must be harvested with minimal time after landing to minimize postflight readaptation alterations in protein expression/translation, posttranslational modifications, and expression, as well as changes in gene expression and tissue histological degradation after euthanasia. We report the development of a widely applicable strategy for determining the window of optimal species-specific and tissue-specific posteuthanasia harvest that can be utilized to integrate into multi-investigator Biospecimen Sharing Programs. We also determined methods for ISS-compatible long-term tissue storage (10 months at -80°C) that yield recovery of high quality mRNA and protein for western analysis after sample return. Our focus was reproductive tissues. The time following euthanasia where tissues could be collected and histological integrity was maintained varied with tissue and species ranging between 1 and 3 hours. RNA quality was preserved in key reproductive tissues fixed in RNAlater up to 40 min after euthanasia. Postfixation processing was also standardized for safe shipment back to our laboratory. Our strategy can be adapted for other tissues under NASA's Biospecimen Sharing Program or similar multi-investigator tissue sharing opportunities.

Nanomaterial-Enabled Dry Electrodes for Electrophysiological Sensing: A Review

NASA Astrophysics Data System (ADS)

Yao, Shanshan; Zhu, Yong

2016-04-01

Long-term, continuous, and unsupervised tracking of physiological data is becoming increasingly attractive for health/wellness monitoring and ailment treatment. Nanomaterials have recently attracted extensive attention as building blocks for flexible/stretchable conductors and are thus promising candidates for electrophysiological electrodes. Here we provide a review on nanomaterial-enabled dry electrodes for electrophysiological sensing, focusing on electrocardiography (ECG). The dry electrodes can be classified into contact surface electrodes, contact-penetrating electrodes, and noncontact capacitive electrodes. Different types of electrodes including their corresponding equivalent electrode-skin interface models and the sources of the noise are first introduced, followed by a review on recent developments of dry ECG electrodes based on various nanomaterials, including metallic nanowires, metallic nanoparticles, carbon nanotubes, and graphene. Their fabrication processes and performances in terms of electrode-skin impedance, signal-to-noise ratio, resistance to motion artifacts, skin compatibility, and long-term stability are discussed.

Outcomes after ABO-incompatible heart transplantation in adults: A registry study.

PubMed

Bergenfeldt, Henrik; Andersson, Bodil; Bućin, Dragan; Stehlik, Josef; Edwards, Leah; Rådegran, Göran; Nilsson, Johan

2015-07-01

In the past, ABO incompatibility was considered an absolute contraindication to heart transplantation (HT) in adults. Advances in ABO-incompatible HT in pediatric patients and ABO-incompatible abdominal transplantation in adult patients have led to clinical exploration of intentional ABO-incompatible HT in adults. However, it is not well known how outcomes in ABO-incompatible adult heart transplant recipients compare with outcomes in ABO-compatible recipients. We analyzed International Society for Heart and Lung Transplantation transplant registry data from heart donors and recipients ≥18 years old at the time of transplant for HT performed between 1988 and 2011. We compared baseline characteristics and post-transplant outcomes in ABO-incompatible and ABO-compatible HT. Death or retransplantation was the composite primary end-point. Among 76,663 adult patients undergoing HT between 1988 and June 30, 2011, 94 ABO-incompatible heart transplants were performed. The incidence of death or retransplantation in the ABO-incompatible group was higher than in the ABO-compatible group: 21% vs 9% at 30 days (hazard ratio = 2.38, p < 0.001) and 36% vs 19% at 1 year after transplant. However, ABO-incompatible grafts surviving past the first year after transplant had a similar incidence of failure compared with the ABO-compatible group. After 2005, the rate ABO-incompatible HT in adults increased, likely as a result of planned, intentional (rather than accidental) ABO-incompatible HT. In this group of patients, short-term and long-term incidence of death or retransplantation was similar to ABO-compatible recipients (p = 0.822): 7% at 30 days and 19% at 1 year after transplantation. We found no difference in incidence of death or retransplantation between ABO-compatible and ABO-incompatible HT in patients who underwent transplantation after 2005. Copyright © 2015 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

A real-time measurement system for long-life flood monitoring and warning applications.

PubMed

Marin-Perez, Rafael; García-Pintado, Javier; Gómez, Antonio Skarmeta

2012-01-01

A flood warning system incorporates telemetered rainfall and flow/water level data measured at various locations in the catchment area. Real-time accurate data collection is required for this use, and sensor networks improve the system capabilities. However, existing sensor nodes struggle to satisfy the hydrological requirements in terms of autonomy, sensor hardware compatibility, reliability and long-range communication. We describe the design and development of a real-time measurement system for flood monitoring, and its deployment in a flash-flood prone 650 km(2) semiarid watershed in Southern Spain. A developed low-power and long-range communication device, so-called DatalogV1, provides automatic data gathering and reliable transmission. DatalogV1 incorporates self-monitoring for adapting measurement schedules for consumption management and to capture events of interest. Two tests are used to assess the success of the development. The results show an autonomous and robust monitoring system for long-term collection of water level data in many sparse locations during flood events.

A Real-Time Measurement System for Long-Life Flood Monitoring and Warning Applications

PubMed Central

Marin-Perez, Rafael; García-Pintado, Javier; Gómez, Antonio Skarmeta

2012-01-01

A flood warning system incorporates telemetered rainfall and flow/water level data measured at various locations in the catchment area. Real-time accurate data collection is required for this use, and sensor networks improve the system capabilities. However, existing sensor nodes struggle to satisfy the hydrological requirements in terms of autonomy, sensor hardware compatibility, reliability and long-range communication. We describe the design and development of a real-time measurement system for flood monitoring, and its deployment in a flash-flood prone 650 km2 semiarid watershed in Southern Spain. A developed low-power and long-range communication device, so-called DatalogV1, provides automatic data gathering and reliable transmission. DatalogV1 incorporates self-monitoring for adapting measurement schedules for consumption management and to capture events of interest. Two tests are used to assess the success of the development. The results show an autonomous and robust monitoring system for long-term collection of water level data in many sparse locations during flood events. PMID:22666028

Environmental compatibility of closed landfills - assessing future pollution hazards.

PubMed

Laner, David; Fellner, Johann; Brunner, Paul H

2011-01-01

Municipal solid waste landfills need to be managed after closure. This so-called aftercare comprises the treatment and monitoring of residual emissions as well as the maintenance and control of landfill elements. The measures can be terminated when a landfill does not pose a threat to the environment any more. Consequently, the evaluation of landfill environmental compatibility includes an estimation of future pollution hazards as well as an assessment of the vulnerability of the affected environment. An approach to assess future emission rates is presented and discussed in view of long-term environmental compatibility. The suggested method consists (a) of a continuous model to predict emissions under the assumption of constant landfill conditions, and (b) different scenarios to evaluate the effects of changing conditions within and around the landfill. The model takes into account the actual status of the landfill, hence different methods to gain information about landfill characteristics have to be applied. Finally, assumptions, uncertainties, and limitations of the methodology are discussed, and the need for future research is outlined.

Neural differences in the processing of true and false sentences: insights into the nature of 'truth' in language comprehension.

PubMed

Marques, J Frederico; Canessa, Nicola; Cappa, Stefano

2009-06-01

The inquiry on the nature of truth in language comprehension has a long history of opposite perspectives. These perspectives either consider that there are qualitative differences in the processing of true and false statements, or that these processes are fundamentally the same and only differ in quantitative terms. The present study evaluated the processing nature of true and false statements in terms of patterns of brain activity using event-related functional-Magnetic-Resonance-Imaging (fMRI). We show that when true and false concept-feature statements are controlled for relation strength/ambiguity, their processing is associated to qualitatively different processes. Verifying true statements activates the left inferior parietal cortex and the caudate nucleus, a neural correlate compatible with an extended search and matching process for particular stored information. In contrast, verifying false statements activates the fronto-polar cortex and is compatible with a reasoning process of finding and evaluating a contradiction between the sentence information and stored knowledge.

Stirling engine - Approach for long-term durability assessment

NASA Technical Reports Server (NTRS)

Tong, Michael T.; Bartolotta, Paul A.; Halford, Gary R.; Freed, Alan D.

1992-01-01

The approach employed by NASA Lewis for the long-term durability assessment of the Stirling engine hot-section components is summarized. The approach consists of: preliminary structural assessment; development of a viscoplastic constitutive model to accurately determine material behavior under high-temperature thermomechanical loads; an experimental program to characterize material constants for the viscoplastic constitutive model; finite-element thermal analysis and structural analysis using a viscoplastic constitutive model to obtain stress/strain/temperature at the critical location of the hot-section components for life assessment; and development of a life prediction model applicable for long-term durability assessment at high temperatures. The approach should aid in the provision of long-term structural durability and reliability of Stirling engines.

Application of DFT-Derived Relationships Between Chemical Environment and 29Si Nuclear Magnetic Resonance Spectroscopy to Determine Structure in Silicon Oxycarbide Ceramics

NASA Astrophysics Data System (ADS)

Nimmo, John Paul, II

Silicon oxycarbide (SiCO) is an amorphous ceramic material widely used in industrial applications, for its useful electronic and biologically-compatible properties. SiCO is resistant to crystallization, remaining amorphous even above temperatures at which amorphous SiO2 would crystallize. Though silica (SiO2) and silicon carbide (SiC) are almost immiscible, it is useful to consider the material as a phase composition of these along with carbon, according to the formula below. The first two terms in braces can be considered as being the "SiCO glass" into which a third term representing excess or "free" carbon is incorporated as graphite-like nano-flakes and bands.

12 CFR 390.384 - Financial statements for conversions, SEC filings, and offering circulars.

Code of Federal Regulations, 2012 CFR

2012-01-01

... balances against long- or short-term borrowing arrangements. This disclosure should include the provisions... long-term borrowings. Include interest on bonds, capital notes, debentures, mortgages on State savings... the exception of disclosure regarding material contingencies, long-term obligations, and guarantees...

Accelerated long-term assessment of thermal and chemical stability of bio-based phase change materials

USDA-ARS?s Scientific Manuscript database

Thermal energy storage (TES) systems incorporated with phase change materials (PCMs) have potential applications to control energy use by building envelopes. However, it is essential to evaluate long term performance of the PCMs and cost effectiveness prior to full scale implementation. For this rea...

[Testing methods for the characterization of catheter balloons and lumina].

PubMed

Werner, C; Rössler, K; Deckert, F

1995-10-01

The present paper reports on the characterization of catheter balloons and lumina on the basis of such known parameters as residual volume, compliance, burst pressure and flow rate, with the aim of developing standards, test methods and testing equipment as well as standards. These are becoming ever more important with the coming into force of the EC directive on medical products [7] and the law governing medical products in Germany [13], which requires manufacturers to specify the properties of their products. Our testing concept is based on a commercially available machine that subjects materials to alternating extension and compression forces over the long-term, to which we added a special hydraulic module. Using the multimedia technology we achieved a real time superimposition of the volume-diameter curve on the balloon. The function of the testing device and method is demonstrated on dilatation catheters. Our initial results reveal compatibility with the requirements of the 1% accuracy class. Use of this methodology for comparative testing of catheters and quality evaluation is recommended.

Surface acoustic wave devices as passive buried sensors

NASA Astrophysics Data System (ADS)

Friedt, J.-M.; Rétornaz, T.; Alzuaga, S.; Baron, T.; Martin, G.; Laroche, T.; Ballandras, S.; Griselin, M.; Simonnet, J.-P.

2011-02-01

Surface acoustic wave (SAW) devices are currently used as passive remote-controlled sensors for measuring various physical quantities through a wireless link. Among the two main classes of designs—resonator and delay line—the former has the advantage of providing narrow-band spectrum informations and hence appears compatible with an interrogation strategy complying with Industry-Scientific-Medical regulations in radio-frequency (rf) bands centered around 434, 866, or 915 MHz. Delay-line based sensors require larger bandwidths as they consists of a few interdigitated electrodes excited by short rf pulses with large instantaneous energy and short response delays but is compatible with existing equipment such as ground penetrating radar (GPR). We here demonstrate the measurement of temperature using the two configurations, particularly for long term monitoring using sensors buried in soil. Although we have demonstrated long term stability and robustness of packaged resonators and signal to noise ratio compatible with the expected application, the interrogation range (maximum 80 cm) is insufficient for most geology or geophysical purposes. We then focus on the use of delay lines, as the corresponding interrogation method is similar to the one used by GPR which allows for rf penetration distances ranging from a few meters to tens of meters and which operates in the lower rf range, depending on soil water content, permittivity, and conductivity. Assuming propagation losses in a pure dielectric medium with negligible conductivity (snow or ice), an interrogation distance of about 40 m is predicted, which overcomes the observed limits met when using interrogation methods specifically developed for wireless SAW sensors, and could partly comply with the above-mentioned applications. Although quite optimistic, this estimate is consistent with the signal to noise ratio observed during an experimental demonstration of the interrogation of a delay line buried at a depth of 5 m in snow.

RP-1 Thermal Stability and Copper Based Materials Compatibility Study

NASA Technical Reports Server (NTRS)

Stiegemeier, B. R.; Meyer, M. L.; Driscoll, E.

2005-01-01

A series of electrically heated tube tests was performed at the NASA Glenn Research Center s Heated Tube Facility to investigate the effect that sulfur content, test duration, and tube material play in the overall thermal stability and materials compatibility characteristics of RP-1. Scanning-electron microscopic (SEM) analysis in conjunction with energy dispersive spectroscopy (EDS) were used to characterize the condition of the tube inner wall surface and any carbon deposition or corrosion formed during these runs. Results of the parametric study indicate that tests with standard RP-1 (total sulfur -23 ppm) and pure copper tubing are characterized by a depostion/deposit shedding process producing local wall temperature swings as high as 500 F. The effect of this shedding is to keep total carbon deposition levels relatively constant for run times from 20 minutes up to 5 hours, though increasing tube pressure drops were observed in all runs. Reduction in the total sulfur content of the fuel from 23 ppm to less than 0.1 ppm resulted in the elimination of deposit shedding, local wall temperature variation, and the tube pressure drop increases that were observed in standard sulfur level RP-1 tests. The copper alloy GRCop-84, a copper alloy developed specifically for high heat flux applications, was found to exhibit higher carbon deposition levels compared to identical tests performed in pure copper tubes. Results of the study are consistent with previously published heated tube data which indicates that small changes in fuel total sulfur content can lead to significant differences in the thermal stability of kerosene type fuels and their compatibility with copper based materials. In conjunction with the existing thermal stability database, these findings give insight into the feasibility of cooling a long life, high performance, high-pressure liquid rocket combustor and nozzle with RP-1.

Long-term effect of lime-fly ash treated soils.

DOT National Transportation Integrated Search

2003-12-01

In October of 2000 MDOT initiated State Study No. 147, entitled "Long-Term Effect of Lime-Fly Ash Treated Soils." The purpose of this study : was to evaluate the long-term performance of LFA stabilized soil as a base course material. Part of the impe...

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

Natesan, K.; Momozaki, Y.; Li, M.

This report gives a description of the activities in design, fabrication, construction, and assembling of a pumped sodium loop for the sodium compatibility studies on advanced structural materials. The work is the Argonne National Laboratory (ANL) portion of the effort on the work project entitled, 'Sodium Compatibility of Advanced Fast Reactor Materials,' and is a part of Advanced Materials Development within the Reactor Campaign. The objective of this project is to develop information on sodium corrosion compatibility of advanced materials being considered for sodium reactor applications. This report gives the status of the sodium pumped loop at Argonne National Laboratory,more » the specimen details, and the technical approach to evaluate the sodium compatibility of advanced structural alloys. This report is a deliverable from ANL in FY2010 (M2GAN10SF050302) under the work package G-AN10SF0503 'Sodium Compatibility of Advanced Fast Reactor Materials.' Two reports were issued in 2009 (Natesan and Meimei Li 2009, Natesan et al. 2009) which examined the thermodynamic and kinetic factors involved in the purity of liquid sodium coolant for sodium reactor applications as well as the design specifications for the ANL pumped loop for testing advanced structural materials. Available information was presented on solubility of several metallic and nonmetallic elements along with a discussion of the possible mechanisms for the accumulation of impurities in sodium. That report concluded that the solubility of many metals in sodium is low (<1 part per million) in the temperature range of interest in sodium reactors and such trace amounts would not impact the mechanical integrity of structural materials and components. The earlier report also analyzed the solubility and transport mechanisms of nonmetallic elements such as oxygen, nitrogen, carbon, and hydrogen in laboratory sodium loops and in reactor systems such as Experimental Breeder Reactor-II, Fast Flux Test Facility, and Clinch River Breeder Reactor. Among the nonmetallic elements discussed, oxygen is deemed controllable and its concentration in sodium can be maintained in sodium for long reactor life by using cold-trap method. It was concluded that among the cold-trap and getter-trap methods, the use of cold trap is sufficient to achieve oxygen concentration of the order of 1 part per million. Under these oxygen conditions in sodium, the corrosion performance of structural materials such as austenitic stainless steels and ferritic steels will be acceptable at a maximum core outlet sodium temperature of {approx}550 C. In the current sodium compatibility studies, the oxygen concentration in sodium will be controlled and maintained at {approx}1 ppm by controlling the cold trap temperature. The oxygen concentration in sodium in the forced convection sodium loop will be controlled and monitored by maintaining the cold trap temperature in the range of 120-150 C, which would result in oxygen concentration in the range of 1-2 ppm. Uniaxial tensile specimens are being exposed to flowing sodium and will be retrieved and analyzed for corrosion and post-exposure tensile properties. Advanced materials for sodium exposure include austenitic alloy HT-UPS and ferritic-martensitic steels modified 9Cr-1Mo and NF616. Among the nonmetallic elements in sodium, carbon was assessed to have the most influence on structural materials since carbon, as an impurity, is not amenable to control and maintenance by any of the simple purification methods. The dynamic equilibrium value for carbon in sodium systems is dependent on several factors, details of which were discussed in the earlier report. The current sodium compatibility studies will examine the role of carbon concentration in sodium on the carburization-decarburization of advanced structural materials at temperatures up to 650 C. Carbon will be added to the sodium by exposure of carbon-filled iron tubes, which over time will enable carbon to diffuse through iron and dissolve into sodium. The method enables addition of dissolved carbon (without carbon particulates) in sodium that is of interest for materials compatibility evaluation. The removal of carbon from the sodium will be accomplished by exposing carbon-gettering alloys such as refractory metals that have a high partitioning coefficient for carbon and also precipitate carbides, thereby decreasing the carbon concentration in sodium.« less

Long-term corrosion evaluation of stainless steels in Space Shuttle iodinated resin and water

NASA Technical Reports Server (NTRS)

Krohn, Douglas D.

1992-01-01

The effects of stainless steel exposure to iodinated water is a concern in developing the Integrated Water System (IWS) for Space Station Freedom. The IWS has a life requirement of 30 years, but the effects of general and localized corrosion over such a long period have not been determined for the candidate materials. In 1978, Umpqua Research Center immersed stainless steel 316L, 321, and 347 specimens in a solution of deionized water and the Space Shuttle microbial check valve resin. In April 1990, the solution was chemically analyzed to determine the level of corrosion formed, and the surface of each specimen was examined with scanning electron microscopy and metallography to determine the extent of general and pitting corrosion. This examination showed that the attack on the stainless steels was negligible and never penetrated past the first grain boundary layer. Of the three alloys, 316L performed the best; however, all three materials proved to be compatible with an aqueous iodine environment. In addition to the specimens exposed to aqueous iodine, a stainless steel specimen (unspecified alloy) was exposed to moist microbial check valve resin and air for a comparable period. This environment allowed contact of the metal to the resin as well as to the iodine vapor. Since the particular stainless steel alloy was not known, energy dispersive spectroscopy was used to determine that this alloy was stainless steel 301. The intergranular corrosion found on the specimen was limited to the first grain boundary layer.

Thermal Performance Study of Composite Phase Change Material with Polyacrylicand Conformal Coating.

PubMed

Kee, Shin Yiing; Munusamy, Yamuna; Ong, Kok Seng; Cornelis Metselaar, Hendrik Simon; Chee, Swee Yong; Lai, Koon Chun

2017-07-28

The composite PCM was prepared by blending polymethyl methacrylate (PMMA) and myristic acid (MA) in different weight percentages. The MA and PMMA were selected as PCM and supporting material, respectively. As liquid MA may leak out during the phase transition, this study proposes the use of two coatings, namely a polyacrylic coating and a conformal coating to overcome the leakage problem. Both coatings were studied in terms of the leakage test, chemical compatibility, thermal stability, morphology, and reliability. No leakage was found in the PCMs with coatings compared to those without under the same proportions of MA/PMMA, thus justifying the use of coatings in the present study. The chemically compatibility was confirmed by FTIR spectra: the functional groups of PCMs were in accordance with those of coatings. DSC showed that the coatings did not significantly change the melting and freezing temperatures, however, they improved the thermal stability of composite PCMs as seen in TGA analysis. Furthermore, the composite PCMs demonstrated good thermal reliability after 1000 times thermal cycling. The latent heat of melting reduced by only 0.16% and 1.02% for the PCMs coated with conformal coating and polyacrylic coating, respectively. Therefore, the proposed coatings can be considered in preparing fatty acid/PMMA blends attributed to the good stability, compatibility and leakage prevention.

An in vitro investigation into the physical properties of irreversible hydrocolloid alternatives.

PubMed

Patel, Rishi D; Kattadiyil, Mathew T; Goodacre, Charles J; Winer, Myron S

2010-11-01

A number of manufacturers have introduced new products that are marketed as alternatives to irreversible hydrocolloid impression materials. However, there is a paucity of laboratory and clinical research on these products compared to traditional irreversible hydrocolloid. The purpose of this study was to evaluate the detail reproduction, gypsum compatibility, and linear dimensional change of 3 recently introduced impression materials designed as alternatives to irreversible hydrocolloid. The tested materials were Position Penta Quick, Silgimix, and AlgiNot. An irreversible hydrocolloid impression material, Jeltrate Plus Antimicrobial, served as the control. The parameters of detail reproduction, gypsum compatibility, and linear dimensional change were tested in accordance with ANSI/ADA Specifications No. 18 and 19. The gypsum compatibility was tested using a type III stone (Microstone Golden) and a type IV stone (Die-Keen Green). The data were analyzed using the Kruskal-Wallis rank test and the Mann-Whitney U test (α=.05). The test materials demonstrated significantly (P<.001) better detail reproduction than the control material. Silgimix exhibited the best compatibility with Microstone, whereas AlgiNot and Position Penta Quick exhibited the best gypsum compatibility with Die-Keen. An incompatibility was observed over time between the Jeltrate control material and the Microstone gypsum material. For linear dimensional change, the mean dimension of the control material most closely approximated the distance between the lines on the test die, but it exhibited the greatest variability in measurements. All of the test materials exhibited linear dimensional change within the ADA's accepted limit of 1.0%. The 3 new impression materials exhibited better detail reproduction and less variability in linear dimensional change than the irreversible hydrocolloid control. Gypsum compatibility varied with the brand of gypsum used, with an incompatibility identified between the control material (Jeltrate Plus Antimicrobial) and Microstone related to surface changes observed over time. Copyright © 2010 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Compatibility of the totally replaced hip. Reduction of wear by amorphous diamond coating.

PubMed

Santavirta, Seppo

2003-12-01

Particulate wear debris in totally replaced hips causes adverse local host reactions. The extreme form of such a reaction, aggressive granulomatosis, was found to be a distinct condition and different from simple aseptic loosening. Reactive and adaptive tissues around the totally replaced hip were made of proliferation of local fibroblast like cells and activated macrophages. Methylmethacrylate and high-molecular-weight polyethylene were shown to be essentially immunologically inert implant materials, but in small particulate form functioned as cellular irritants initiating local biological reactions leading to loosening of the implants. Chromium-cobalt-molybdenum is the most popular metallic implant material; it is hard and tough, and the bearings of this metal are partially self-polishing. In total hip implants, prerequisites for longevity of the replaced hip are good biocompatibility of the materials and sufficient tribological properties of the bearings. The third key issue is that the bearing must minimize frictional shear at the prosthetic bone-implant interface to be compatible with long-term survival. Some of the approaches to meet these demands are alumina-on-alumina and metal-on-metal designs, as well as the use of highly crosslinked polyethylene for the acetabular component. In order to avoid the wear-based deleterious properties of the conventional total hip prosthesis materials or coatings, the present work included biological and tribological testing of amorphous diamond. Previous experiments had demonstrated that a high adhesion of tetrahedral amorphous carbon coatings to a substrate can be achieved by using mixing layers or interlayers. Amorphous diamond was found to be biologically inert, and simulator testing indicated excellent wear properties for conventional total hip prostheses, in which either the ball or both bearing surfaces were coated with hydrogen-free tetrahedral amorphous diamond films. Simulator testing with such total hip prostheses showed no measurable wear or detectable delamination after 15,000,000 test cycles corresponding to 15 years of clinical use. The present work clearly shows that wear is one of the basic problems with totally replaced hips. Diamond coating of the bearing surfaces appears to be an attractive solution to improve longevity of the totally replaced hip.

Long-term performance of thermoplastic composite material with cotton burr and stem (CBS) as a partial filler

USDA-ARS?s Scientific Manuscript database

Rationale: Cotton burr and stem (CBS) fraction of cotton gin byproducts has shown promise as a fiber filler in thermoplastic composites, with physical and mechanical properties comparable to that made with wood fiber fillers. However, the long-term performance of this composite material is not known...

The Ships Below-Decks Electromagnetic Compatibility (EMC) Program. A compilation of Papers Presented at the 1987 IEEE International Symposium on EMC

DTIC Science & Technology

1987-09-30

were producing below-deck environ - such that after 24 hours the performance loss ranged mental levels exceeding the "normal" environmental from 13 to...SGA performance environmental EMI testing in the electromagnetically measurements b- made in the laboratory. However, it quiet laboratory environments ... Environmentally Sealed SGAs.................................... 1-1 Need for Long Term SGA Performance Evaluation .................... 1-2 Performance

Composite structural materials

NASA Technical Reports Server (NTRS)

Loewy, R.; Wiberley, S. E.

1986-01-01

Overall emphasis is on basic long-term research in the following categories: constituent materials, composite materials, generic structural elements, processing science technology; and maintaining long-term structural integrity. Research in basic composition, characteristics, and processing science of composite materials and their constituents is balanced against the mechanics, conceptual design, fabrication, and testing of generic structural elements typical of aerospace vehicles so as to encourage the discovery of unusual solutions to present and future problems. Detailed descriptions of the progress achieved in the various component parts of this comprehensive program are presented.

Army’s Evalution of Aviation Fuel Contaminants Using Electronic Sensors

DTIC Science & Technology

2012-04-13

and free water contamination challenges, testing of mechanical integrity in response to pressure and material compatibility. 15. SUBJECT TERMS 16...4406 • Turbidity/photometers used in beer/ wine industry • Challenge – Being able to determine both particulate and water contamination...looking at real-time methods for determining fuel cleanliness • Some “re-inventing of the wheel” occurred • Products went to the field without

Long-Term Monitoring of Pavement Maintenance Materials Test Sites

DOT National Transportation Integrated Search

1998-06-01

The Strategic Highway Research Program's {SHRP) H-106 pothole repair experiment was part of the most extensive pavement maintenance experiment ever conducted. Started under SHRP and continued under the Long-Term Pavement Performance program's Long-Te...

The influence of the Japanese waving cat on the joint spatial compatibility effect: A replication and extension of Dolk, Hommel, Prinz, and Liepelt (2013).

PubMed

Puffe, Lydia; Dittrich, Kerstin; Klauer, Karl Christoph

2017-01-01

In a joint go/no-go Simon task, each of two participants is to respond to one of two non-spatial stimulus features by means of a spatially lateralized response. Stimulus position varies horizontally and responses are faster and more accurate when response side and stimulus position match (compatible trial) than when they mismatch (incompatible trial), defining the social Simon effect or joint spatial compatibility effect. This effect was originally explained in terms of action/task co-representation, assuming that the co-actor's action is automatically co-represented. Recent research by Dolk, Hommel, Prinz, and Liepelt (2013) challenged this account by demonstrating joint spatial compatibility effects in a task-setting in which non-social objects like a Japanese waving cat were present, but no real co-actor. They postulated that every sufficiently salient object induces joint spatial compatibility effects. However, what makes an object sufficiently salient is so far not well defined. To scrutinize this open question, the current study manipulated auditory and/or visual attention-attracting cues of a Japanese waving cat within an auditory (Experiment 1) and a visual joint go/no-go Simon task (Experiment 2). Results revealed that joint spatial compatibility effects only occurred in an auditory Simon task when the cat provided auditory cues while no joint spatial compatibility effects were found in a visual Simon task. This demonstrates that it is not the sufficiently salient object alone that leads to joint spatial compatibility effects but instead, a complex interaction between features of the object and the stimulus material of the joint go/no-go Simon task.

Optical frequency locked loop for long-term stabilization of broad-line DFB laser frequency difference

NASA Astrophysics Data System (ADS)

Lipka, Michał; Parniak, Michał; Wasilewski, Wojciech

2017-09-01

We present an experimental realization of the optical frequency locked loop applied to long-term frequency difference stabilization of broad-line DFB lasers along with a new independent method to characterize relative phase fluctuations of two lasers. The presented design is based on a fast photodiode matched with an integrated phase-frequency detector chip. The locking setup is digitally tunable in real time, insensitive to environmental perturbations and compatible with commercially available laser current control modules. We present a simple model and a quick method to optimize the loop for a given hardware relying exclusively on simple measurements in time domain. Step response of the system as well as phase characteristics closely agree with the theoretical model. Finally, frequency stabilization for offsets within 4-15 GHz working range achieving <0.1 Hz long-term stability of the beat note frequency for 500 s averaging time period is demonstrated. For these measurements we employ an I/Q mixer that allows us to precisely and independently measure the full phase trace of the beat note signal.

Long-term solar UV radiation reconstructed by ANN modelling with emphasis on spatial characteristics of input data

NASA Astrophysics Data System (ADS)

Feister, U.; Junk, J.; Woldt, M.; Bais, A.; Helbig, A.; Janouch, M.; Josefsson, W.; Kazantzidis, A.; Lindfors, A.; den Outer, P. N.; Slaper, H.

2008-06-01

Artificial Neural Networks (ANN) are efficient tools to derive solar UV radiation from measured meteorological parameters such as global radiation, aerosol optical depths and atmospheric column ozone. The ANN model has been tested with different combinations of data from the two sites Potsdam and Lindenberg, and used to reconstruct solar UV radiation at eight European sites by more than 100 years into the past. Special emphasis will be given to the discussion of small-scale characteristics of input data to the ANN model. Annual totals of UV radiation derived from reconstructed daily UV values reflect interannual variations and long-term patterns that are compatible with variabilities and changes of measured input data, in particular global dimming by about 1980/1990, subsequent global brightening, volcanic eruption effects such as that of Mt. Pinatubo, and the long-term ozone decline since the 1970s. Patterns of annual erythemal UV radiation are very similar at sites located at latitudes close to each other, but different patterns occur between UV radiation at sites in different latitude regions.

Comparison of shrinkage related properties of various patch repair materials

NASA Astrophysics Data System (ADS)

Kristiawan, S. A.; Fitrianto, R. S.

2017-02-01

A patch repair material has been developed in the form of unsaturated polyester resin (UPR)-mortar. The performance and durability of this material are governed by its compatibility with the concrete being repaired. One of the compatibility issue that should be tackled is the dimensional compatibility as a result of differential shrinkage between the repair material and the concrete substrate. This research aims to evaluate such shrinkage related properties of UPR-mortar and to compare with those of other patch repair materials. The investigation includes the following aspects: free shrinkage, resistance to delamination and cracking. The results indicate that UPR-mortar poses a lower free shrinkage, lower risk of both delamination and cracking tendency in comparison to other repair materials.

Influence of long-term thermal aging on the microstructural evolution of nuclear reactor pressure vessel materials: An atom probe study

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

Pareige, P.; Russell, K.F.; Stoller, R.E.

1998-03-01

Atom probe field ion microscopy (APFIM) investigations of the microstructure of unaged (as-fabricated) and long-term thermally aged ({approximately} 100,000 h at 280 C) surveillance materials from commercial reactor pressure vessel steels were performed. This combination of materials and conditions permitted the investigation of potential thermal-aging effects. This microstructural study focused on the quantification of the compositions of the matrix and carbides. The APFIM results indicate that there was no significant microstructural evolution after a long-term thermal exposure in weld, plate, or forging materials. The matrix depletion of copper that was observed in weld materials was consistent with the copper concentrationmore » in the matrix after the stress-relief heat treatment. The compositions of cementite carbides aged for 100,000 h were compared with the Thermocalc{trademark} prediction. The APFIM comparisons of materials under these conditions are consistent with the measured change in mechanical properties such as the Charpy transition temperature.« less

Working memory, long-term memory, and medial temporal lobe function

PubMed Central

Jeneson, Annette; Squire, Larry R.

2012-01-01

Early studies of memory-impaired patients with medial temporal lobe (MTL) damage led to the view that the hippocampus and related MTL structures are involved in the formation of long-term memory and that immediate memory and working memory are independent of these structures. This traditional idea has recently been revisited. Impaired performance in patients with MTL lesions on tasks with short retention intervals, or no retention interval, and neuroimaging findings with similar tasks have been interpreted to mean that the MTL is sometimes needed for working memory and possibly even for visual perception itself. We present a reappraisal of this interpretation. Our main conclusion is that, if the material to be learned exceeds working memory capacity, if the material is difficult to rehearse, or if attention is diverted, performance depends on long-term memory even when the retention interval is brief. This fundamental notion is better captured by the terms subspan memory and supraspan memory than by the terms short-term memory and long-term memory. We propose methods for determining when performance on short-delay tasks must depend on long-term (supraspan) memory and suggest that MTL lesions impair performance only when immediate memory and working memory are insufficient to support performance. In neuroimaging studies, MTL activity during encoding is influenced by the memory load and correlates positively with long-term retention of the material that was presented. The most parsimonious and consistent interpretation of all the data is that subspan memoranda are supported by immediate memory and working memory and are independent of the MTL. PMID:22180053

Effects of physical aging on long-term creep of polymers and polymer matrix composites

NASA Technical Reports Server (NTRS)

Brinson, L. Catherine; Gates, Thomas S.

1994-01-01

For many polymeric materials in use below the glass transition temperature, the long term viscoelastic behavior is greatly affected by physical aging. To use polymer matrix composites as critical structural components in existing and novel technological applications, this long term behavior of the material system must be understood. Towards that end, this study applied the concepts governing the mechanics of physical aging in a consistent manner to the study of laminated composite systems. Even in fiber-dominated lay-ups the effects of physical aging are found to be important in the long-term behavior of the composite. The basic concepts describing physical aging of polymers are discussed. Several aspects of physical aging which have not been previously documented are also explored in this study, namely the effects of aging into equilibrium and a relationship to the time-temperature shift factor. The physical aging theory is then extended to develop the long-term compliance/modulus of a single lamina with varying fiber orientation. The latter is then built into classical lamination theory to predict long-time response of general oriented lamina and laminates. It is illustrated that the long term response can be counterintuitive, stressing the need for consistent modeling efforts to make long term predictions of laminates to be used in structural situations.

Blood Compatibility of Sulfonated Cladophora Nanocellulose Beads.

PubMed

Rocha, Igor; Lindh, Jonas; Hong, Jaan; Strømme, Maria; Mihranyan, Albert; Ferraz, Natalia

2018-03-07

Sulfonated cellulose beads were prepared by oxidation of Cladophora nanocellulose to 2,3-dialdehyde cellulose followed by sulfonation using bisulfite. The physicochemical properties of the sulfonated beads, i.e., high surface area, high degree of oxidation, spherical shape, and the possibility of tailoring the porosity, make them interesting candidates for the development of immunosorbent platforms, including their application in extracorporeal blood treatments. A desired property for materials used in such applications is blood compatibility; therefore in the present work, we investigate the hemocompatibility of the sulfonated cellulose beads using an in vitro whole blood model. Complement system activation (C3a and sC5b-9 levels), coagulation activation (thrombin-antithrombin (TAT) levels) and hemolysis were evaluated after whole blood contact with the sulfonated beads and the results were compared with the values obtained with the unmodified Cladophora nanocellulose. Results showed that neither of the cellulosic materials presented hemolytic activity. A marked decrease in TAT levels was observed after blood contact with the sulfonated beads, compared with Cladophora nanocellulose. However, the chemical modification did not promote an improvement in Cladophora nanocellulose hemocompatibility in terms of complement system activation. Even though the sulfonated beads presented a significant reduction in pro-coagulant activity compared with the unmodified material, further modification strategies need to be investigated to control the complement activation by the cellulosic materials.

Long-term stability and properties of zirconia ceramics for heavy duty diesel engine components

NASA Technical Reports Server (NTRS)

Larsen, D. C.; Adams, J. W.

1985-01-01

Physical, mechanical, and thermal properties of commercially available transformation-toughened zirconia are measured. Behavior is related to the material microstructure and phase assemblage. The stability of the materials is assessed after long-term exposure appropriate for diesel engine application. Properties measured included flexure strength, elastic modulus, fracture toughness, creep, thermal shock, thermal expansion, internal friction, and thermal diffusivity. Stability is assessed by measuring the residual property after 1000 hr/1000C static exposure. Additionally static fatigue and thermal fatigue testing is performed. Both yttria-stabilized and magnesia-stabilized materials are compared and contrasted. The major limitations of these materials are short term loss of properties with increasing temperature as the metastable tetragonal phase becomes more stable. Fine grain yttria-stabilized material (TZP) is higher strength and has a more stable microstructure with respect to overaging phenomena. The long-term limitation of Y-TZP is excessive creep deformation. Magnesia-stabilized PSZ has relatively poor stability at elevated temperature. Overaging, decomposition, and/or destabilization effects are observed. The major limitation of Mg-PSZ is controlling unwanted phase changes at elevated temperature.

Vital correspondence: Exploring tactile experience with resident-focused mandalas in long-term care (Innovative practice).

PubMed

Graham, Megan E; Fabricius, Andréa

2018-01-01

The materiality of long-term care and its relationship to a resident's identity is often overlooked. In response to the call for more attention to the meaningful aspects of doing art, the tactile experience of residents with dementia is considered in the context of a mandala project at a Canadian seniors' long-term care facility. The significance of making mandalas for residents is explored through three key themes: identity integration through gesture, the importance of artistic discernment and decision-making, and the value of corresponding with recalcitrant materials. Residents' experiences are analysed through a phenomenological lens.

Resistive switching phenomena of tungsten nitride thin films with excellent CMOS compatibility

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

Hong, Seok Man; Kim, Hee-Dong; An, Ho-Myoung

2013-12-15

Graphical abstract: - Highlights: • The resistive switching characteristics of WN{sub x} thin films. • Excellent CMOS compatibility WN{sub x} films as a resistive switching material. • Resistive switching mechanism revealed trap-controlled space charge limited conduction. • Good endurance and retention properties over 10{sup 5} cycles, and 10{sup 5} s, respectively - Abstract: We report the resistive switching (RS) characteristics of tungsten nitride (WN{sub x}) thin films with excellent complementary metal-oxide-semiconductor (CMOS) compatibility. A Ti/WN{sub x}/Pt memory cell clearly shows bipolar RS behaviors at a low voltage of approximately ±2.2 V. The dominant conduction mechanisms at low and high resistancemore » states were verified by Ohmic behavior and trap-controlled space-charge-limited conduction, respectively. A conducting filament model by a redox reaction explains the RS behavior in WN{sub x} films. We also demonstrate the memory characteristics during pulse operation, including a high endurance over >10{sup 5} cycles and a long retention time of >10{sup 5} s.« less

Synthesis of a novel biomedical poly(ester urethane) based on aliphatic uniform-size diisocyanate and the blood compatibility of PEG-grafted surfaces.

PubMed

Liu, Xiaolong; Xia, Yiran; Liu, Lulu; Zhang, Dongmei; Hou, Zhaosheng

2018-05-01

The purpose of this study is to offer a novel kind of polyurethane with improved surface blood compatibility for long-term implant biomaterials. In this work, the aliphatic poly(ester-urethane) (PEU) with uniform-size hard segments was prepared and the PEU surface was grafted with hydrophilic poly(ethylene glycol) (PEG). The PEU was obtained by chain-extension of poly(ɛ-caprolactone) (PCL) with isocyanate-terminated urethane triblock. Free amino groups were introduced onto the surface of PEU film via aminolysis with hexamethylenediamine, and then the NH 2 -grafted PEU surfaces (PEU-NH 2 ) were reacted with isocyanate-terminated monomethoxyl PEG (MPEG-NCO) to obtain the PEG-grafted PEU surfaces (PEU-PEG). Analysis by nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and gel permeation chromatography were performed to confirm the chemical structures of the chain extender, PCL, PEU, and PEU-PEG. Additionally, the influence of aminolysis on the physical-mechanical properties of PEU films was investigated. Two glass transition temperatures and a broad endothermic peak were observed in the differential scanning calorimetry curves of PEU, which demonstrated a microphase-separated and semicrystalline structure, respectively. The PEU-PEG film exhibited excellent mechanical properties with an ultimate stress of ∼39 MPa and an elongation at break of ∼1190%, which was slightly lower than that of PEU, indicating that the aminolysis has little influence on the tensile properties. Evaluation of the blood compatibility of the films by bovine serum albumin adsorption and the platelet adhesion test revealed that the PEG-grafted surface had improved resistance to protein adsorption and excellent resistance to platelet adhesion. In vitro degradation tests showed that the PEU-PEG film could maintain its mechanical properties for more than six months and only lost ∼25% weight after 18 months. Due to the excellent mechanical properties, good blood compatibility and slow degradability, this novel kind of polyurethane hold significant promise for long-term implant biomaterials, especially soft tissue augmentation and regeneration.

Physical effects of DCNQI derivatives doping as an N type organic semiconductor in organic photovoltaic cell performance.

PubMed

Lee, Joo Hyung; Oh, Se Young

2014-08-01

In the previous work, we have reported that organic photovoltaic (OPV) cells using DMDCNQI as an n-type second dopant material showed a high power conversion efficiency (PCE). In the present work, we have synthesized a novel DHDCNQI with long alkyl chains to improve the compatibility between the DHDCNQI dopant molecule and host P3HT polymer. We have fabricated OPV cells consisting of ITO/PEDOT:PSS/P3HT:PCBM:DHDCNQI/Al. We have investigated the characteristics of theses OPV cells using DCNQI derivative dopants from the measurements of the incident photon-to-current collection efficiency and photocurrent. The OPV cell using 3 wt% DHDCNQI exhibited a high PCE of 3.29% due to the high charge separation efficiency, good compatibility and low trap site effect.

High density grids

DOEpatents

Cohen, Aina E.; Baxter, Elizabeth L.

2018-01-16

An X-ray data collection grid device is provided that includes a magnetic base that is compatible with robotic sample mounting systems used at synchrotron beamlines, a grid element fixedly attached to the magnetic base, where the grid element includes at least one sealable sample window disposed through a planar synchrotron-compatible material, where the planar synchrotron-compatible material includes at least one automated X-ray positioning and fluid handling robot fiducial mark.

Integrating Agriculture and Conservation

USGS Publications Warehouse

Vandever, Mark W.

2010-01-01

The USGS produces the needed science-based information to guide management actions and policy decisions that support wildlife habitat and other environmental services compatible with USDA conservation goals and farm operations. The Policy Analysis and Science Assistance Branch of the Fort Collins Science Center (FORT) has conducted research involving a national landowner survey and numerous short- and long-term evaluations regarding vegetation responses to land management practices. This research helps land and resource managers to make informed decisions and resolve resource management conflicts.

Dissecting the long-term emission behaviour of the BL Lac object Mrk 421

NASA Astrophysics Data System (ADS)

Carnerero, M. I.; Raiteri, C. M.; Villata, M.; Acosta-Pulido, J. A.; Larionov, V. M.; Smith, P. S.; D'Ammando, F.; Agudo, I.; Arévalo, M. J.; Bachev, R.; Barnes, J.; Boeva, S.; Bozhilov, V.; Carosati, D.; Casadio, C.; Chen, W. P.; Damljanovic, G.; Eswaraiah, E.; Forné, E.; Gantchev, G.; Gómez, J. L.; González-Morales, P. A.; Griñón-Marín, A. B.; Grishina, T. S.; Holden, M.; Ibryamov, S.; Joner, M. D.; Jordan, B.; Jorstad, S. G.; Joshi, M.; Kopatskaya, E. N.; Koptelova, E.; Kurtanidze, O. M.; Kurtanidze, S. O.; Larionova, E. G.; Larionova, L. V.; Latev, G.; Lázaro, C.; Ligustri, R.; Lin, H. C.; Marscher, A. P.; Martínez-Lombilla, C.; McBreen, B.; Mihov, B.; Molina, S. N.; Moody, J. W.; Morozova, D. A.; Nikolashvili, M. G.; Nilsson, K.; Ovcharov, E.; Pace, C.; Panwar, N.; Pastor Yabar, A.; Pearson, R. L.; Pinna, F.; Protasio, C.; Rizzi, N.; Redondo-Lorenzo, F. J.; Rodríguez-Coira, G.; Ros, J. A.; Sadun, A. C.; Savchenko, S. S.; Semkov, E.; Slavcheva-Mihova, L.; Smith, N.; Strigachev, A.; Troitskaya, Yu. V.; Troitsky, I. S.; Vasilyev, A. A.; Vince, O.

2017-12-01

We report on long-term multiwavelength monitoring of blazar Mrk 421 by the GLAST-AGILE Support Program of the Whole Earth Blazar Telescope (GASP-WEBT) collaboration and Steward Observatory, and by the Swift and Fermi satellites. We study the source behaviour in the period 2007-2015, characterized by several extreme flares. The ratio between the optical, X-ray and γ-ray fluxes is very variable. The γ-ray flux variations show a fair correlation with the optical ones starting from 2012. We analyse spectropolarimetric data and find wavelength-dependence of the polarization degree (P), which is compatible with the presence of the host galaxy, and no wavelength dependence of the electric vector polarization angle (EVPA). Optical polarimetry shows a lack of simple correlation between P and flux and wide rotations of the EVPA. We build broad-band spectral energy distributions with simultaneous near-infrared and optical data from the GASP-WEBT and ultraviolet and X-ray data from the Swift satellite. They show strong variability in both flux and X-ray spectral shape and suggest a shift of the synchrotron peak up to a factor of ∼50 in frequency. The interpretation of the flux and spectral variability is compatible with jet models including at least two emitting regions that can change their orientation with respect to the line of sight.

A promising biodegradable magnesium alloy suitable for clinical vascular stent application

PubMed Central

Mao, Lin; shen, Li; Chen, Jiahui; Zhang, Xiaobo; Kwak, Minsuk; Wu, Yu; Fan, Rong; Zhang, Lei; Pei, Jia; Yuan, Guangyin; Song, Chengli; Ge, Junbo; Ding, Wenjiang

2017-01-01

We report a Mg alloy Mg-2.2Nd-0.1Zn-0.4Zr (wt.%, denoted as JDBM-2) showing great potential in clinical vascular stent application by integrating the advantages of traditional medical stainless steel and polymer. This alloy exhibits high yield strength and elongation of 276 ± 6 MPa and 34.3 ± 3.4% respectively. The JDBM-2 with a stable degradation surface results in a highly homogeneous degradation mechanism and long-term structural and mechanical durability. In vitro cytotoxicity test of the Mg extract via human vascular endothelial cells (HUVECs) indicates that the corrosion products are well tolerated by the tested cells and potentially negligible toxic effect on arterial vessel walls. This alloy also exhibits compromised foreign body response (FBR) determined by human peripheral blood derived macrophage adhesion, foreign body giant cell (FBGC) formation and inflammatory cytokine and chemokine secretion. Finally, vascular stents manufactured from the JDBM-2 were implanted into rabbits for long-term evaluation. The results confirm excellent tissue compatibility and up to 6-month structural and mechanical integrity of the stent in vivo. Thus, the JDBM-2 stent with up to 6-month structural and mechanical integrity and excellent tissue compatibility represents a major breakthrough in this field and a promising alternative to traditional medical stainless steel and polymer for the clinical application. PMID:28397881

Nanofibrous polymeric beads from aramid fibers for efficient bilirubin removal.

PubMed

Peng, Zihang; Yang, Ye; Luo, Jiyue; Nie, Chuanxiong; Ma, Lang; Cheng, Chong; Zhao, Changsheng

2016-08-16

Polymer based hemoperfusion has been developed as an effective therapy to remove the extra bilirubin from patients. However, the currently applied materials suffer from either low removal efficiency or poor blood compatibility. In this study, we report the development of a new class of nanofibrous absorbent that exhibited high bilirubin removal efficiency and good blood compatibility. The Kevlar nanofiber was prepared by dissolving micron-sized Kevlar fiber in proper solvent, and the beads were prepared by dropping Kevlar nanofiber solutions into ethanol. Owing to the nanofiborous structure of the Kevlar nanofiber, the beads displayed porous structures and large specific areas, which would facilitate the adsorption of toxins. In the adsorption test, it was noticed that the beads possessed an adsorption capacity higher than 40 mg g(-1) towards bilirubin. In plasma mimetic solutions, the beads still showed high bilirubin removal efficiency. Furthermore, after incorporating with carbon nanotubes, the beads were found to have increased adsorption capacity for human degradation waste. Moreover, the beads showed excellent blood compatibility in terms of a low hemolysis ratio, prolonged clotting times, suppressed coagulant activation, limited platelet activation, and inhibited blood related inflammatory activation. Additionally, the beads showed good compatibility with endothelial cells. In general, the Kevlar nanofiber beads, which integrated with high adsorption capacity, good blood compatibility and low cytotoxicity, may have great potential for hemoperfusion and some other applications in biomedical fields.

Malignant mesothelioma

MedlinePlus

... abdomen (peritoneum). It is due to long-term asbestos exposure. ... Long-term exposure to asbestos is the biggest risk factor. Asbestos is a fire-resistant material. It was once commonly found in insulation, ceiling and ...

Minimally invasive surgical techniques for stress incontinence surgery.

PubMed

Morley, Roland; Nethercliffe, Janine

2005-12-01

Minimally invasive techniques for surgical correction of stress incontinence date back to the late 1950s. Since that time there have been many developments to attempt to emulate the good results achieved by open surgery with less surgical morbidity. Needle suspensions have attempted to reposition the bladder neck in the same way as a colposuspension. However, although numerous variations have been described, they do not have the long-term outcomes of colposuspension. These variations, their complications and long-term outcome are discussed. Sling surgery, especially the tension-free vaginal tape (TVT), has probably had the largest impact on incontinence surgery in recent years, offering a procedure with low morbidity and, thus far in the medium term, outcomes comparable with those of more invasive procedures. This has led the TVT procedure to become the most common procedure performed worldwide for stress incontinence. With the benefit of lessons learnt from the use of synthetic material in the genitourinary tract, some worries remain with regard to the long-term complications of TVT. Other non-synthetic material should not be forgotten, and the advantages and disadvantages of various sling materials are compared. Injectables have an established place in the treatment of sphincter deficiency, though long-term results are poor compared to those of other procedures. Various materials used and the technique for their injection are discussed.

Oxygen Compatibility Testing of Composite Materials

NASA Technical Reports Server (NTRS)

Graf, Neil A.; Hudgins, Richard J.; McBain, Michael

2000-01-01

The development of polymer composite liquid oxygen LO2 tanks is a critical step in creating the next generation of launch vehicles. Future launch vehicles need to minimize the gross liftoff weight (GLOW), which is possible due to the 25%-40% reduction in weight that composite materials could provide over current aluminum technology. Although a composite LO2 tank makes these weight savings feasible, composite materials have not historically been viewed as "LO2 compatible." To be considered LO2 compatible, materials must be selected that will resist any type of detrimental, combustible reaction when exposed to usage environments. This is traditionally evaluated using a standard set of tests. However, materials that do not pass the standard tests can be shown to be safe for a particular application. This paper documents the approach and results of a joint NASA/Lockheed Martin program to select and verify LO2 compatible composite materials for liquid oxygen fuel tanks. The test approach developed included tests such as mechanical impact, particle impact, puncture, electrostatic discharge, friction, and pyrotechnic shock. These tests showed that composite liquid oxygen tanks are indeed feasible for future launch vehicles.

Compatibility of refrigerants and lubricants with motor materials. Volume 1, Final report

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

Doerr, R.; Kujak, S.

This volume contains the abstract, scope, discussion of results, charts of motor material compatibility, test procedures, material identifications, and 84 pages of data summary tables. Compatibility test results for 11 pure refrigerants and 17 refrigerant-lubricant combinations with 24 motor materials are included. The greatest effect on the motor materials was caused by adsorption followed by desorption of refrigerants at higher temperatures. High internal pressure of the adsorbed refrigerants and their tendency to evolve from the materials resulted in blisters, cracks, internal bubbles in the varnish, and delamination or bubbles in the sheet insulations. The second effect was extraction or dissolutionmore » of materials that lead to embrittlement of some sheet insulations. HCFC-22 and HCFC- 22/mineral oil had the most deleterious effects; the materials are expected to be reliable when used with most of the new refrigerants and lubricants. Tables.« less

Factors Affecting Long-Term Abstinence from Substances Use

ERIC Educational Resources Information Center

Elsheikh, Salah Elgaily

2008-01-01

Objective: The purpose of this study is to explore the attitudes of abstainers from drug use that relate to the factors leading to long-term abstinence. Materials and Methods: Cross-sectional study was carried out in Al-Amal Hospital to examine, which attitudes of abstainers related to long-term abstinence. A random survey was conducted on 62…

Thermodynamic analysis of chemical compatibility of several compounds with Fe-Cr-Al alloys

NASA Technical Reports Server (NTRS)

Misra, Ajay K.

1993-01-01

Chemical compatibility between Fe-19.8Cr-4.8Al (weight percent), which is the base composition for the commercial superalloy MA956, and several carbides, borides, nitrides, oxides, and silicides was analyzed from thermodynamic considerations. The effect of addition of minor alloying elements, such as Ti, Y, and Y2O3, to the Fe-Cr-Al alloy on chemical compatibility between the alloy and various compounds was also analyzed. Several chemically compatible compounds that can be potential reinforcement materials and/or interface coating materials for Fe-Cr-Al based composites were identified.

Gas production apparatus

DOEpatents

Winsche, Warren E.; Miles, Francis T.; Powell, James R.

1976-01-01

This invention relates generally to the production of gases, and more particularly to the production of tritium gas in a reliable long operating lifetime systems that employs solid lithium to overcome the heretofore known problems of material compatibility and corrosion, etc., with liquid metals. The solid lithium is irradiated by neutrons inside low activity means containing a positive (+) pressure gas stream for removing and separating the tritium from the solid lithium, and these means are contained in a low activity shell containing a thermal insulator and a neutron moderator.

In orbit degradation of EUV optical components in the wavelength range 10-40 nm AO 138-3

NASA Technical Reports Server (NTRS)

Delaboudiniere, J. P.; Carabetian, C.; Hochedez, J. F.

1993-01-01

A complement of EUV optical components, including mirrors and thin film filters, was flown as part of the Long Duration Exposure Facility (LDEF) AO 138-3. The most original amongst these components were multilayered interference reflectors for the 10-40 nm wavelength range. Very moderate degradation was observed for those components which were exposed to the sun. The degradation is compatible with the deposition of a few nanometers of absorbing material on the surface of the samples.

Distribution and Variation of Indole Glucosinolates in Woad (Isatis tinctoria L.) 1

PubMed Central

Elliott, Malcolm C.; Stowe, Bruce B.

1971-01-01

The exceptionally high levels in woad (Isatis tinctoria L.) of three indolic goitrogens, namely glucobrassicin, neoglucobrassicin, and glucobrassicin-1-sulfonate, permit the facile study of their distribution in the plant and their changes during its development. Woad seeds contain as much as 0.23% fresh weight of glucobrassicin but no other indole glucosinolate, while 1-week-old seedlings also contain substantial amounts of neoglucobrassicin and glucobrassicin-1-sulfonate in their shoots whether grown in the light or dark. The sulfonate is not found in roots, and light depresses neoglucobrassicin levels in shoots. Sterile root cultures synthesize glucobrassicin and neoglucobrassicin, and significant quantities of these were even found to be excreted by the roots of intact sterile seedlings in culture. This may explain the long known deleterious effect of woad and other cruciferous crops on subsequent plantings and the observation could be of ecological importance. Long term changes in levels of all three substances in the plant are similar and are compatible with earlier suggestions that the compounds could be auxin precursors at the time of flower stem elongation. Since sterile seedlings readily incorporate 35SO42− into indole glucosinolates and relative specific radioactivities suggest that glucobrassicin is the precursor of the other two compounds, pathways of goitrogen biosynthesis should be relatively easily determined in this material. PMID:16657825

Distribution and Variation of Indole Glucosinolates in Woad (Isatis tinctoria L.).

PubMed

Elliott, M C; Stowe, B B

1971-10-01

The exceptionally high levels in woad (Isatis tinctoria L.) of three indolic goitrogens, namely glucobrassicin, neoglucobrassicin, and glucobrassicin-1-sulfonate, permit the facile study of their distribution in the plant and their changes during its development. Woad seeds contain as much as 0.23% fresh weight of glucobrassicin but no other indole glucosinolate, while 1-week-old seedlings also contain substantial amounts of neoglucobrassicin and glucobrassicin-1-sulfonate in their shoots whether grown in the light or dark. The sulfonate is not found in roots, and light depresses neoglucobrassicin levels in shoots. Sterile root cultures synthesize glucobrassicin and neoglucobrassicin, and significant quantities of these were even found to be excreted by the roots of intact sterile seedlings in culture. This may explain the long known deleterious effect of woad and other cruciferous crops on subsequent plantings and the observation could be of ecological importance. Long term changes in levels of all three substances in the plant are similar and are compatible with earlier suggestions that the compounds could be auxin precursors at the time of flower stem elongation. Since sterile seedlings readily incorporate (35)SO(4) (2-) into indole glucosinolates and relative specific radioactivities suggest that glucobrassicin is the precursor of the other two compounds, pathways of goitrogen biosynthesis should be relatively easily determined in this material.

Bioglass: A novel biocompatible innovation.

PubMed

Krishnan, Vidya; Lakshmi, T

2013-04-01

Advancement of materials technology has been immense, especially in the past 30 years. Ceramics has not been new to dentistry. Porcelain crowns, silica fillers in composite resins, and glass ionomer cements have already been proved to be successful. Materials used in the replacement of tissues have come a long way from being inert, to compatible, and now regenerative. When hydroxyapatite was believed to be the best biocompatible replacement material, Larry Hench developed a material using silica (glass) as the host material, incorporated with calcium and phosphorous to fuse broken bones. This material mimics bone material and stimulates the regrowth of new bone material. Thus, due to its biocompatibility and osteogenic capacity it came to be known as "bioactive glass-bioglass." It is now encompassed, along with synthetic hydroxyapatite, in the field of biomaterials science known as "bioactive ceramics." The aim of this article is to give a bird's-eye view, of the various uses in dentistry, of this novel, miracle material which can bond, induce osteogenesis, and also regenerate bone.

Alternative Fuels Compatibility with Army Equipment Testing - Alternative Fuels Material Compatibility Analysis

DTIC Science & Technology

2012-02-21

Testing and Materials °C Celsius DiEGME Diethylene Glycol Monomethyl Ether EPDM Ethylene Propylene Diene Monomer FARE Forward Area Refueling...urethane class AU, polyether urethane class EU, EPDM , Viton®, fluorosilicone class FQ, polytetrafluoroethylene (PTFE), polyolefin and polyester...sleeve Material not provided AAFARS 4720-00-540-1368 Hose, nonmetallic Material not provided AAFARS 4720-01-218-6958 Hose, preformed Rubber

Thickness and character of regolith on mountain slopes in the vicinity of Mountain Lake, Virginia, as indicated by seismic refraction, and implications for hillslope evolution

NASA Astrophysics Data System (ADS)

Mills, Hugh H.

1990-06-01

Seismic refraction was used to determine the variation in thickness and seismic velocities of regolith on boulder-mantled mountain flanks underlain by shale in the Valley and Ridge province near Mountain Lake, southwestern Virginia. Emphasis was on cross-slope variations, particularly the difference between dells (hollows) and noses. Four types of material were distinguished on the basis of seismic velocity. Soil material within 1-2 m of the ground surface affected by pedogenesis had a velocity generally less than 400 m/s. Unconsolidated bouldery colluvium, up to 6 m thick, had a velocity of about 400-800 m/s. Old, weathered and consolidated colluvium had a velocity of 800-2000 m/s. Bedrock residuum and highly weathered bedrock showed similar velocities, however, so that all material in this range was collectively termed "weathered regolith." Its thickness exceeded 30 m in places. Relatively unweathered bedrock showed velocities of at least 2000 m/s. On average, seismic profiles showed regolith thicknesses in excess of 10 m, the greater part being residuum or weathered bedrock. This finding contrasts with one study near the glacial border in Pennsylvania, which showed that colluvium generally directly overlies bedrock. This difference may reflect less-intense Pleistocene periglacial erosion in Virginia than in Pennsylvania. Topography generally was not a good predictor of regolith thickness. Hollows showed greater thicknesses of ypung colluvium than did noses, but dells and noses showed little difference in total regolith thickness. Both dells and noses showed great variation in regolith thickness. The largest systematic difference was found between dell floors (or parts thereof) that seemed to be undergoing long-term downcutting and those that appeared to be relict features no longer associated with active drainageways. The former were underlain by a mean of 5.5 m of weathered regolith, whereas the latter were underlain by a mean of 14.0 m, indicative of a greater depth of weathering and therefore a greater antiquity. On three noses, closely spaced seismic profiles were used to demonstrate asymmetric distribution of regolith thickness in a direction transverse to nose axes. Findings are compatible with the concept that noses and dells on the boulder-mantled mountain slopes undergo topographic inversion during long-term retreat of the mountain front.

Double Retort System for Materials Compatibility Testing

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

V. Munne; EV Carelli

2006-02-23

With Naval Reactors (NR) approval of the Naval Reactors Prime Contractor Team (NRPCT) recommendation to develop a gas cooled reactor directly coupled to a Brayton power conversion system as the Space Nuclear Power Plant (SNPP) for Project Prometheus (References a and b) there was a need to investigate compatibility between the various materials to be used throughout the SNPP. Of particular interest was the transport of interstitial impurities from the nickel-base superalloys, which were leading candidates for most of the piping and turbine components to the refractory metal alloys planned for use in the reactor core. This kind of contaminationmore » has the potential to affect the lifetime of the core materials. This letter provides technical information regarding the assembly and operation of a double retort materials compatibility testing system and initial experimental results. The use of a double retort system to test materials compatibility through the transfer of impurities from a source to a sink material is described here. The system has independent temperature control for both materials and is far less complex than closed loops. The system is described in detail and the results of three experiments are presented.« less

Sealing Materials for Use in Vacuum at High Temperatures

NASA Technical Reports Server (NTRS)

Pettit, Donald R.; Camarda, Charles J.; Lee Vaughn, Wallace

2012-01-01

Sealing materials that can be applied and left in place in vacuum over a wide range of temperatures (especially temperatures of a few thousand degrees Celsius) have been conceived and investigated for potential utility in repairing thermal-protection tiles on the space shuttles in orbit before returning to Earth. These materials are also adaptable to numerous terrestrial applications that involve vacuum processing and/or repair of structures that must withstand high temperatures. These materials can be formulated to have mechanical handling characteristics ranging from almost freely flowing liquid-like consistency through paste-like consistency to stiff puttylike consistency, and to retain these characteristics in vacuum until heated to high curing temperatures. A sealing material of this type can be formulated to be used in any of several different ways for example, to be impregnated into a high-temperature-fabric patch, impregnated into a high-temperature-fabric gasket for sealing a patch, applied under a patch, or applied alone in the manner of putty or wallboard compound. The sealing material must be formulated to be compatible with, and adhere to, the structural material(s) to be repaired. In general, the material consists of a vacuum-compatible liquid containing one or more dissolved compound(s) and/or mixed with suspended solid particles. Depending on the intended application, the liquid can be chosen to be of a compound that can remain in place in vacuum for a time long enough to be useful, and/or to evaporate or decompose in a controlled way to leave a useful solid residue behind. The evaporation rate is determined by proper choice of vapor pressure, application of heat, and/or application of ultraviolet light or other optical radiation. The liquid chosen for the original space shuttle application is a commercial silicone vacuum-pump oil.

Enabling Dissimilar Material Joining Using Friction Stir Scribe Technology

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

Hovanski, Yuri; Upadyay, Piyush; Kleinbaum, Sarah

2017-04-05

One challenge in adapting welding processes to dissimilar material joining is the diversity of melting temperatures of the different materials. Although the use of mechanical fasteners and adhesives have mostly paved the way for near-term implementation of dissimilar material systems, these processes only accentuate the need for low-cost welding processes capable of joining dissimilar material components regardless of alloy, properties, or melting temperature. Friction stir scribe technology was developed to overcome the challenges of joining dissimilar material components where melting temperatures vary greatly, and properties and/or chemistry are not compatible with more traditional welding processes. Although the friction stir scribemore » process is capable of joining dissimilar metals and metal/polymer systems, a more detailed evaluation of several aluminum/steel joints is presented herein to demonstrate the ability to both chemically and mechanically join dissimilar materials.« less

Enabling Dissimilar Material Joining Using Friction Stir Scribe Technology

DOE PAGES

Hovanski, Yuri; Upadyay, Piyush; Kleinbaum, Sarah; ...

2017-04-05

One challenge in adapting welding processes to dissimilar material joining is the diversity of melting temperatures of the different materials. Although the use of mechanical fasteners and adhesives have mostly paved the way for near-term implementation of dissimilar material systems, these processes only accentuate the need for low-cost welding processes capable of impartially joining dissimilar material components regardless of alloy, properties, or melting temperature. Friction stir scribe technology was developed to overcome the challenges of joining dissimilar material components where melting temperatures vary greatly, and properties and/or chemistry are not compatible with more traditional welding processes. Finally, although the frictionmore » stir scribe process is capable of joining dissimilar metals and metal/polymer systems, a more detailed evaluation of several aluminum/steel joints is presented herein to demonstrate the ability to both chemically and mechanically join dissimilar materials.« less

Native fish conservation areas: A vision for large-scale conservation of native fish communities

USGS Publications Warehouse

Williams, Jack E.; Williams, Richard N.; Thurow, Russell F.; Elwell, Leah; Philipp, David P.; Harris, Fred A.; Kershner, Jeffrey L.; Martinez, Patrick J.; Miller, Dirk; Reeves, Gordon H.; Frissell, Christopher A.; Sedell, James R.

2011-01-01

The status of freshwater fishes continues to decline despite substantial conservation efforts to reverse this trend and recover threatened and endangered aquatic species. Lack of success is partially due to working at smaller spatial scales and focusing on habitats and species that are already degraded. Protecting entire watersheds and aquatic communities, which we term "native fish conservation areas" (NFCAs), would complement existing conservation efforts by protecting intact aquatic communities while allowing compatible uses. Four critical elements need to be met within a NFCA: (1) maintain processes that create habitat complexity, diversity, and connectivity; (2) nurture all of the life history stages of the fishes being protected; (3) include a long-term enough watershed to provide long-term persistence of native fish populations; and (4) provide management that is sustainable over time. We describe how a network of protected watersheds could be created that would anchor aquatic conservation needs in river basins across the country.

Compatibility tests of materials for a lithium-cooled space power reactor concept

NASA Technical Reports Server (NTRS)

Sinclair, J. H.

1973-01-01

Materials for a lithium-cooled space power reactor concept must be chemically compatible for up to 50,000 hr at high temperature. Capsule tests at 1040 C (1900 F) were made of material combinations of prime interest: T-111 in direct contact with uranium mononitride (UN), Un in vacuum separated from T-111 by tungsten wire, UN with various oxygen impurity levels enclosed in tungsten wire lithium-filled T-111 capsules, and TZM and lithium together in T-111 capsules. All combinations were compatible for over 2800 hr except for T-111 in direct contact with UN.

Selective hydrophilic modification of Parylene C films: a new approach to cell micro-patterning for synthetic biology applications.

PubMed

Trantidou, T; Rao, C; Barrett, H; Camelliti, P; Pinto, K; Yacoub, M H; Athanasiou, T; Toumazou, C; Terracciano, C M; Prodromakis, T

2014-06-01

We demonstrate a simple, accurate and versatile method to manipulate Parylene C, a material widely known for its high biocompatibility, and transform it to a substrate that can effectively control the cellular microenvironment and consequently affect the morphology and function of the cells in vitro. The Parylene C scaffolds are fabricated by selectively increasing the material's surface water affinity through lithography and oxygen plasma treatment, providing free bonds for attachment of hydrophilic biomolecules. The micro-engineered constructs were tested as culture scaffolds for rat ventricular fibroblasts and neonatal myocytes (NRVM), toward modeling the unique anisotropic architecture of native cardiac tissue. The scaffolds induced the patterning of extracellular matrix compounds and therefore of the cells, which demonstrated substantial alignment compared to typical unstructured cultures. Ca(2+) cycling properties of the NRVM measured at rates of stimulation 0.5-2 Hz were significantly modified with a shorter time to peak and time to 90% decay, and a larger fluorescence amplitude (p < 0.001). The proposed technique is compatible with standard cell culturing protocols and exhibits long-term pattern durability. Moreover, it allows the integration of monitoring modalities into the micro-engineered substrates for a comprehensive interrogation of physiological parameters.

Capillarity Guided Patterning of Microliquids.

PubMed

Kang, Myeongwoo; Park, Woohyun; Na, Sangcheol; Paik, Sang-Min; Lee, Hyunjae; Park, Jae Woo; Kim, Ho-Young; Jeon, Noo Li

2015-06-01

Soft lithography and other techniques have been developed to investigate biological and chemical phenomena as an alternative to photolithography-based patterning methods that have compatibility problems. Here, a simple approach for nonlithographic patterning of liquids and gels inside microchannels is described. Using a design that incorporates strategically placed microstructures inside the channel, microliquids or gels can be spontaneously trapped and patterned when the channel is drained. The ability to form microscale patterns inside microfluidic channels using simple fluid drain motion offers many advantages. This method is geometrically analyzed based on hydrodynamics and verified with simulation and experiments. Various materials (i.e., water, hydrogels, and other liquids) are successfully patterned with complex shapes that are isolated from each other. Multiple cell types are patterned within the gels. Capillarity guided patterning (CGP) is fast, simple, and robust. It is not limited by pattern shape, size, cell type, and material. In a simple three-step process, a 3D cancer model that mimics cell-cell and cell-extracellular matrix interactions is engineered. The simplicity and robustness of the CGP will be attractive for developing novel in vitro models of organ-on-a-chip and other biological experimental platforms amenable to long-term observation of dynamic events using advanced imaging and analytical techniques. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Exploring long-wave infrared transmitting materials with AxBy form: First-principles gene-like studies.

PubMed

Du, Jia-Ren; Chen, Nian-Ke; Li, Xian-Bin; Xie, Sheng-Yi; Tian, Wei Quan; Wang, Xian-Yin; Tu, Hai-Ling; Sun, Hong-Bo

2016-02-23

Long-wave infrared (8-12 μm) transmitting materials play critical roles in space science and electronic science. However, the paradox between their mechanical strength and infrared transmitting performance seriously prohibits their applications in harsh external environment. From the experimental view, searching a good window material compatible with both properties is a vast trail-and-error engineering project, which is not readily achieved efficiently. In this work, we propose a very simple and efficient method to explore potential infrared window materials with suitable mechanical property by first-principles gene-like searching. Two hundred and fifty-three potential materials are evaluated to find their bulk modulus (for mechanical performance) and phonon vibrational frequency (for optical performance). Seven new potential candidates are selected, namely TiSe, TiS, MgS, CdF2, HgF2, CdO, and SrO. Especially, the performances of TiS and CdF2 can be comparable to that of the most popular commercial ZnS at high temperature. Finally, we propose possible ranges of infrared transmission for halogen, chalcogen and nitrogen compounds respectively to guide further exploration. The present strategy to explore IR window materials can significantly speed up the new development progress. The same idea can be used for other material rapid searching towards special functions and applications.

A high resolution pneumatic stepping actuator for harsh reactor environments

NASA Astrophysics Data System (ADS)

Tippetts, Thomas B.; Evans, Paul S.; Riffle, George K.

1993-01-01

A reactivity control actuator for a high-power density nuclear propulsion reactor must be installed in close proximity to the reactor core. The energy input from radiation to the actuator structure could exceed hundreds of W/cc unless low-cross section, low-absorptivity materials are chosen. Also, for post-test handling and subsequent storage, materials should not be used that are activated into long half-life isotopes. Pneumatic actuators can be constructed from various reactor-compatible materials, but conventional pneumatic piston actuators generally lack the stiffness required for high resolution reactivity control unless electrical position sensors and compensated electronic control systems are used. To overcome these limitations, a pneumatic actuator is under development that positions an output shaft in response to a series of pneumatic pulses, comprising a pneumatic analog of an electrical stepping motor. The pneumatic pulses are generated remotely, beyond the strong radiation environment, and transmitted to the actuator through tubing. The mechanically simple actuator uses a nutating gear harmonic drive to convert motion of small pistons directly to high-resolution angular motion of the output shaft. The digital nature of this actuator is suitable for various reactor control algorithms but is especially compatible with the three bean salad algorithm discussed by Ball et al. (1991).

Bespoke analogue space-times: meta-material mimics

NASA Astrophysics Data System (ADS)

Schuster, Sebastian; Visser, Matt

2018-06-01

Modern meta-materials allow one to construct electromagnetic media with almost arbitrary bespoke permittivity, permeability, and magneto-electric tensors. If (and only if) the permittivity, permeability, and magneto-electric tensors satisfy certain stringent compatibility conditions, can the meta-material be fully described (at the wave optics level) in terms of an effective Lorentzian metric—an analogue spacetime. We shall consider some of the standard black-hole spacetimes of primary interest in general relativity, in various coordinate systems, and determine the equivalent meta-material susceptibility tensors in a laboratory setting. In static black hole spacetimes (Schwarzschild and the like) certain eigenvalues of the susceptibility tensors will be seen to diverge on the horizon. In stationary black hole spacetimes (Kerr and the like) certain eigenvalues of the susceptibility tensors will be seen to diverge on the ergo-surface.

Long-Term Durability of Pressure-Treated Wood in a Severe Test Site

Treesearch

Stan Lebow; Bessie Woodward; Grant Kirker; Patricia Lebow

2013-01-01

Improved estimates of the long-term durability of treated wood products are needed to guide choices about construction materials and allow estimates of design life. This report summarizes the long-term decay and insect resistance of treated wood post and lumber specimens placed in ground contact at a test site of the U.S. Department of Agriculture, Forest Service,...

76 FR 60935 - Notice of Application from ExxonMobil Corporation, Highland Uranium Mine and Millsite, To Amend...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-30

... and Extend the NRC Long-Term Surveillance Boundary With Respect to Materials License SUA-1139 AGENCY... concentration limits and to extend the NRC Long-Term Surveillance Boundary at its Highland Uranium Mine and Mill... wells and at the proposed POC well. The amendment also proposes to expand the Long-Term Surveillance...

Ceramic Borehole Seals for Nuclear Waste Disposal Applications

NASA Astrophysics Data System (ADS)

Lowry, B.; Coates, K.; Wohletz, K.; Dunn, S.; Patera, E.; Duguid, A.; Arnold, B.; Zyvoloski, G.; Groven, L.; Kuramyssova, K.

2015-12-01

Sealing plugs are critical features of the deep borehole system design. They serve as structural platforms to bear the weight of the backfill column, and as seals through their low fluid permeability and bond to the borehole or casing wall. High hydrostatic and lithostatic pressures, high mineral content water, and elevated temperature due to the waste packages and geothermal gradient challenge the long term performance of seal materials. Deep borehole nuclear waste disposal faces the added requirement of assuring performance for thousands of years in large boreholes, requiring very long term chemical and physical stability. A high performance plug system is being developed which capitalizes on the energy of solid phase reactions to form a ceramic plug in-situ. Thermites are a family of self-oxidized metal/oxide reactions with very high energy content and the ability to react under water. When combined with engineered additives the product exhibits attractive structural, sealing, and corrosion properties. In the initial phase of this research, exploratory and scaled tests demonstrated formulations that achieved controlled, fine grained, homogeneous, net shape plugs composed predominantly of ceramic material. Laboratory experiments produced plug cores with confined fluid permeability as low as 100 mDarcy, compressive strength as high as 70 MPa (three times the strength of conventional well cement), with the inherent corrosion resistance and service temperature of ceramic matrices. Numerical thermal and thermal/structural analyses predicted the in-situ thermal performance of the reacted plugs, showing that they cooled to ambient temperature (and design strength) within 24 to 48 hours. The current development effort is refining the reactant formulations to achieve desired performance characteristics, developing the system design and emplacement processes to be compatible with conventional well service practices, and understanding the thermal, fluid, and structural effects the plug will have on surrounding media. This paper will report on the state of the development effort and plans for a field demonstration in early 2016 in a cased well with traditional plug seal and strength measurements.

40 CFR 174.508 - Pesticidal substance from sexually compatible plant; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2014 CFR

2014-07-01

... the requirement of a tolerance if all the following conditions are met: (a) The genetic material that... plant that is sexually compatible with the recipient food plant. (b) The genetic material has never been...

Space environmental effects on materials

NASA Technical Reports Server (NTRS)

Schwinghmaer, R. J.

1980-01-01

The design of long life platforms and structures for space is discussed in terms of the space environmental effects on the materials used. Vacuum, ultraviolet radiation, and charged particle radiation are among the factors considered. Research oriented toward the acquisition of long term environmental effects data needed to support the design and development of large low Earth orbit and geosynchronous Earth orbit space platforms and systems is described.

When Does Retrieval Induce Forgetting and when Does It Induce Facilitation? Implications for Retrieval Inhibition, Testing Effect, and Text Processing

ERIC Educational Resources Information Center

Chan, Jason C. K.

2009-01-01

Retrieval practice can enhance long-term retention of the tested material (the testing effect), but it can also impair later recall of the nontested material--a phenomenon known as retrieval-induced forgetting (Anderson, M. C., Bjork, R. A., & Bjork, E. L. (1994). "Remembering can cause forgetting: retrieval dynamics in long-term memory." "Journal…

Screening of High Temperature Organic Materials for Future Stirling Convertors

NASA Technical Reports Server (NTRS)

Shin, Euy-sik E.; Scheiman, Daniel A.

2017-01-01

Along with major advancement of Stirling-based convertors, high temperature organics are needed to develop future higher temperature convertors for much improved efficiencies as well as to improve the margin of reliability for the current SOA (State-of-the-Art) convertors. The higher temperature capabilities would improve robustness of the convertors and also allow them to be used in additional missions, particularly ones that require a Venus flyby for a gravity assist. Various organic materials have been employed as essential components in the convertor for their unique properties and functions such as bonding, potting, sealing, thread locking, insulation, and lubrication. The Stirling convertor radioisotope generators have been developed for potential future space applications including Lunar/Mars surface power or a variety of spacecraft and vehicles, especially with a long mission cycle, sometimes up to 17 years, such as deep space exploration. Thus, performance, durability, and reliability of the organics should be critically evaluated in terms of every possible material structure-process-service environment relations based on the potential mission specifications. The initial efforts in screening the high temperature candidates focused on the most susceptible organics, such as adhesive, potting compound, O-ring, shrink tubing, and thread locker materials in conjunction with commercially available materials. More systematic and practical test methodologies that were developed and optimized based on the extensive organic evaluations and validations performed for various Stirling convertor types were employed to determine thermal stability, outgassing, and material compatibility of the selected organic candidates against their functional requirements. Processing and fabrication conditions and procedures were also optimized. This report presents results of the three-step candidate evaluation processes, their application limitations, and the final selection recommendations.

Effect of Time on Gypsum-Impression Material Compatibility

NASA Astrophysics Data System (ADS)

Won, John Boram

The purpose of this study was to evaluate the compatibility of dental gypsum with three recently introduced irreversible hydrocolloid (alginate) alternatives. The test materials were Alginot® (Kerr™), Position Penta Quick® (3M ESPE™) and Silgimix ® (Sultan Dental™). The irreversible hydrocolloid impression material, Jeltrate Plus antimicrobial® (Dentsply Caulk™) served as the control. Materials and Methods: Testing of materials was conducted in accordance with ANSI/ADA Specification No. 18 for Alginate Impression Materials. Statistical Analysis: The 3-Way ANOVA test was used to analyze measurements between different time points at a significance level of (p < 0.05). Outcome: It was found that there was greater compatibility between gypsum and the alternative materials over time than the traditional irreversible hydrocolloid material that was tested. A statistically significant amount of surface change/incompatibility was found over time with the combination of the dental gypsum products and the control impression material (Jeltrate Plus antimicrobial®).

Compositional Evolution of Saturn's Ring: Ice, Tholin, and 'CHIRON'-Dust

NASA Technical Reports Server (NTRS)

Cuzzi, Jeffrey N.; Estrada, P. R.; DeVincenzi, Donald L. (Technical Monitor)

1996-01-01

We address compositional evolution in planetary ring systems subsequent to meteoroid bombardment. The huge surface area to mass ratio of planetary rings ensures the importance of this process, given currently expected values of meteoroid flux. We developed a model which includes both direct deposition of extrinsic meteoritic 'pollutants', and ballistic transport of the increasingly polluted ring material as impact ejecta. Certain aspects of the observed regional variations in ring color and albedo can be understood in terms of such a process. We conclude that the regional scale color and albedo differences between the C ring and B ring can be understood if all ring material began with the same composition (primarily water ice, based on other data, but colored by tiny amounts of non-icy, reddish absorber) and then evolved entirely by addition and mixing of extrinsic, neutrally colored, highly absorbing material. This conclusion is readily extended to the Cassini Division and its surroundings as well. Typical silicates are unable to satisfy the ring color, spectroscopic, and microwave absorption constraints either as intrinsic or extrinsic non-icy constituents. However, 'Titan Tholin' provides a satisfactory match for the inferred refractive indices of the 'pre-pollution' nonicy ring material. The extrinsic bombarding material is compatible with the properties of Halley or Chiron, but not with the properties of other 'red' primitive objects such as Pholus. We further demonstrate that the detailed radial profile of color across the abrupt B ring - C ring boundary is quite compatible with such a 'pollution transport' process, and that the shape of the profile can constrain key parameters in the model. We use the model to estimate the 'exposure age' of Saturn's rings to extrinsic meteoroid flux. We obtain a geologically young 'age' which is compatible with timescales estimated independently based on the evolution of ring structure due to ballistic transport, and also with other 'short timescales' estimated on the grounds of gravitational torques.

Provider software buyer's guide.

PubMed

1994-03-01

To help long term care providers find new ways to improve quality of care and efficiency, Provider magazine presents the fourth annual listing of software firms marketing computer programs for all areas of nursing facility operations. On the following five pages, more than 80 software firms display their wares, with programs such as minimum data set and care planning, dietary, accounting and financials, case mix, and medication administration records. The guide also charts compatible hardware, integration ability, telephone numbers, company contacts, and easy-to-use reader service numbers.

Provider software buyer's guide.

PubMed

1993-03-01

To help long term care providers find new ways to improve quality of care and efficiency. Provider magazine presents the third annual listing of software firms marketing computer programs for all areas of nursing facility operations. On the following five pages, more than 80 software firms display their wares, with programs such as minimum data set and care planning, dietary, accounting and financials, case mix, and medication administration records. The guide also charts compatible hardware, integration ability, telephone numbers, company contacts, and easy-to-use reader service numbers.

Long-term pavement performance ancillary information management system (AIMS) reference guide.

DOT National Transportation Integrated Search

2012-11-01

This document provides information on the Long-Term Pavement Performance (LTPP) program ancillary information. : Ancillary information includes data, images, reference materials, resource documents, and other information that : support and extend the...

Satellite networks in the ISDN era

NASA Astrophysics Data System (ADS)

Amadesi, P.; Haines, P.; Patacchini, A.

1986-12-01

The development of an integrated service digital network (ISDN) capable of supporting a wide range of services using a small set of standard multipurpose user-network interfaces is examined. The ISDN environment is expected to consist of functional elements such as, circuit switching, packet switching, and common channel signaling. The use of satellites or fiber optics in the ISDN is evaluated. The relation between satellites and the ISDN in the short-, medium-, and long-terms is analyzed. The recommendations of the consultative committee, CCIR, concerning the definition of the hypothetical reference digital path and the required quality and availability for ISDN applications, and the proposed plans of Eutelsat and Intelsat for satellite systems compatible with an ISDN are discussed. The application of business satellite networks and packet satellite networks to an ISDN is studied. The long-term objectives for an ISDN is a wideband system that accommodates digital transmission on circuit and packet switched bases.

Long-term C. elegans immobilization enables high resolution developmental studies in vivo.

PubMed

Berger, Simon; Lattmann, Evelyn; Aegerter-Wilmsen, Tinri; Hengartner, Michael; Hajnal, Alex; deMello, Andrew; Casadevall I Solvas, Xavier

2018-05-01

Live-imaging of C. elegans is essential for the study of conserved cellular pathways (e.g. EGFR/Wnt signaling) and morphogenesis in vivo. However, the usefulness of live imaging as a research tool has been severely limited by the need to immobilize worms prior to and during imaging. Conventionally, immobilization is achieved by employing both physical and chemical interventions. These are known to significantly affect many physiological processes, and thus limit our understanding of dynamic developmental processes. Herein we present a novel, easy-to-use microfluidic platform for the long-term immobilization of viable, normally developing C. elegans, compatible with image acquisition at high resolution, thereby overcoming the limitations associated with conventional worm immobilization. The capabilities of the platform are demonstrated through the continuous assessment of anchor cell (AC) invasion and distal tip cell (DTC) migration in larval C. elegans and germ cell apoptosis in adult C. elegans in vivo for the first time.

Ultralow-power near-infrared excited neodymium-doped nanoparticles for long-term in vivo bioimaging.

PubMed

Qin, Qing-Song; Zhang, Pei-Zhi; Sun, Ling-Dong; Shi, Shuo; Chen, Nai-Xiu; Dong, Hao; Zheng, Xiao-Yu; Li, Le-Min; Yan, Chun-Hua

2017-04-06

Lanthanide-doped luminescent nanoparticles with both emission and excitation in the near-infrared (NIR-to-NIR) region hold great promise for bioimaging. Herein, core@shell structured LiLuF 4 :Nd@LiLuF 4 (named as Nd@Lu) nanoparticles (NPs) with highly efficient NIR emission were developed for high-performance in vivo bioimaging. Strikingly, the absolute quantum yield of Nd@Lu NPs reached as high as 32%. After coating with polyethylene glycol (PEG), the water-dispersible Nd@Lu NPs showed good bio-compatibility and low toxicity. With efficient NIR emission, the Nd@Lu NPs were clearly detectable in tissues at depths of up to 20 mm. In addition, long-term in vivo biodistribution with a high signal-to-noise ratio of 25.1 was distinctly tracked upon an ultralow-power-density excitation (10 mW cm -2 ) of 732 nm for the first time.

Biological induced corrosion of materials II: New test methods and experiences from mir station

NASA Astrophysics Data System (ADS)

Klintworth, R.; Reher, H. J.; Viktorov, A. N.; Bohle, D.

1999-09-01

During previous long-term manned missions, more than 100 species of microorganisms have been identified on surfaces of materials (bacteria and fungi). Among them were potentially pathogenic ones (saprophytes) which are capable of active growth on artificial substrates, as well as technophilic bacteria and fungi causing damages (destruction and degradation) to various materials (metals and polymers), resulting in failures and disruptions in the functioning of equipment and hardware. Aboard a space vehicle some microclimatic parameters are optimal for microorganism growth: the atmospheric fluid condensate with its specific composition, chemical and/or antropogenic contaminants (human metobolic products, etc.) all are stimulating factors for the development of bacteria and mould fungi on materials of the interior and equipment of an orbital station during its operational phase(s). Especially Russian long-term missions (SALJUT, MIR) have demonstrated that uncontrolled interactions of microorganisms with materials will ultimately lead to the appearence of technological and medical risks, significantly influencing safety and reliability characteristics of individual as well as whole systems and/ or subsystems. For a first conclusion, it could be summarized, that countermeasures and anti-strategies focussing on Microbial Contamination Management (MCM) for the International Space Station (ISS, next long-term manned mission) at least require a new materials test approach. Our respective concept includes a combined age-ing/biocorrosion test sequence. It is represented here, as well as current status of MCM program, e.g. continuous monitoring (microbiological analyses), long-term disinfection, frequent cleaning methods, mathematical modeling of ISS, etc.

First-principles screening of structural properties of intermetallic compounds on martensitic transformation

NASA Astrophysics Data System (ADS)

Lee, Joohwi; Ikeda, Yuji; Tanaka, Isao

2017-11-01

Martensitic transformation with good structural compatibility between parent and martensitic phases are required for shape memory alloys (SMAs) in terms of functional stability. In this study, first-principles-based materials screening is systematically performed to investigate the intermetallic compounds with the martensitic phases by focusing on energetic and dynamical stabilities as well as structural compatibility with the parent phase. The B2, D03, and L21 crystal structures are considered as the parent phases, and the 2H and 6M structures are considered as the martensitic phases. In total, 3384 binary and 3243 ternary alloys with stoichiometric composition ratios are investigated. It is found that 187 alloys survive after the screening. Some of the surviving alloys are constituted by the chemical elements already widely used in SMAs, but other various metallic elements are also found in the surviving alloys. The energetic stability of the surviving alloys is further analyzed by comparison with the data in Materials Project Database (MPD) to examine the alloys whose martensitic structures may cause further phase separation or transition to the other structures.

Metals production

NASA Technical Reports Server (NTRS)

Beck, Theodore S.

1992-01-01

Existing procedures for design of electrochemical plants can be used for design of lunar processes taking into consideration the differences in environmental conditions. These differences include: 1/6 Earth gravity, high vacuum, solar electrical and heat source, space radiation heat sink, long days and nights, and different availability and economics of materials, energy, and labor. Techniques have already been developed for operation of relatively small scale hydrogen-oxygen fuel cell systems used in the U.S. lunar landing program. Design and operation of lunar aqueous electrolytic process plants appears to be within the state-of-the-art. Finding or developing compatible materials for construction and designing of fused-magma metal winning cells will present a real engineering challenge.

COMPATIBILITY OF NAPLS AND OTHER ORGANIC COMPOUNDS WITH MATERIALS UED IN WELL CONSTRUCTION, SAMPLING, AND REMEDIATION

EPA Science Inventory

Structural integrity of well construction, sampling, and remediation materials may be compromised at many hazardous sites by nonaqueous phase liquids (NAPLs) and their dissolved constituents. A literature review of compatibility theory and qualitative field experiences are provid...

Nursing Assistants for Long-Term Care. Performance-Based Instructional Materials.

ERIC Educational Resources Information Center

Indiana Univ., Bloomington. Vocational Education Services.

This guide is intended to assist students enrolled in programs to train nursing assistants for employment in an Indiana long-term health care facility. The first part discusses human development (growth, aging, and dying); communication with residents; sexuality; legal, ethical, and professional responsibilities of nursing assistants in long-term…

Chemical compatibility and properties of suspension plasma-sprayed SrTiO3-based anodes for intermediate-temperature solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Zhang, Shan-Lin; Li, Cheng-Xin; Li, Chang-Jiu

2014-10-01

La-doped strontium titanate (LST) is a promising, redox-stable perovskite material for direct hydrocarbon oxidation anodes in intermediate-temperature solid oxide fuel cells (IT-SOFCs). In this study, nano-sized LST and Sm-doped ceria (SDC) powders are produced by the sol-gel and glycine-nitrate processes, respectively. The chemical compatibility between LST and electrolyte materials is studied. A LST-SDC composite anode is prepared by suspension plasma spraying (SPS). The effects of annealing conditions on the phase structure, microstructure, and chemical stability of the LST-SDC composite anode are investigated. The results indicate that the suspension plasma-sprayed LST-SDC anode has the same phase structure as the original powders. LST exhibits a good chemical compatibility with SDC and Mg/Sr-doped lanthanum gallate (LSGM). The anode has a porosity of ∼40% with a finely porous structure that provides high gas permeability and a long three-phase boundary for the anode reaction. Single cells assembled with the LST-SDC anode, La0.8Sr0.2Ga0.8Mg0.2O3 electrolyte, and La0.8Sr0.2CoO3-SDC cathode show a good performance at 650-800 °C. The annealing reduces the impedances due to the enhancement in the bonding between the particles in the anode and interface of anode and LSGM electrolyte, thus improving the output performance of the cell.

Materials research for high-speed civil transport and generic hypersonics: Composites durability

NASA Technical Reports Server (NTRS)

Allen-Lilly, Heather; Cregger, Eric; Hoffman, Daniel; Mccool, Jim

1995-01-01

This report covers a portion of an ongoing investigation of the durability of composites for the High Speed Civil Transport (HSCT) program. Candidate HSCT composites need to possess the high-temperature capability required for supersonic flight. This program was designed to initiate the design, analysis, fabrication, and testing of equipment intended for use in validating the long-term durability of materials for the HSCT. This equipment includes thermally actuated compression and tension fixtures, hydraulic-actuated reversible load fixtures, and thermal chambers. This equipment can be used for the durability evaluation of both composite and adhesive materials. Thermally actuated fixtures are recommended for fatigue cycling when long-term thermomechanical fatigue (TMF) data are required on coupon-sized tension or compression specimens. Long term durability testing plans for polymer matrix composite specimens are included.

Biogeography and organic matter removal shape long-term effects of timber harvesting on forest soil microbial communities

Treesearch

Roland C Wilhelm; Erick Cardenas; Kendra R Maas; Hilary Leung; Larisa McNeil; Shannon Berch; William Chapman; Graeme Hope; J M Kranabetter; Stephane Dubé; Matt Busse; Robert Fleming; Paul Hazlett; Kara L Webster; David Morris; D Andrew Scott; William W Mohn

2017-01-01

The growing demand for renewable, carbon-neutral materials and energy is leading to intensified forest land-use. The long-term ecological challenges associated with maintaining soil fertility in managed forests are not yet known, in part due to the complexity of soil microbial communities and the heterogeneity of forest soils. This study determined the long-term...

Depth of Ultra High Energy Cosmic Ray Induced Air Shower Maxima Measured by the Telescope Array Black Rock and Long Ridge FADC Fluorescence Detectors and Surface Array in Hybrid Mode

NASA Astrophysics Data System (ADS)

Abbasi, R. U.; Abe, M.; Abu-Zayyad, T.; Allen, M.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Cheon, B. G.; Chiba, J.; Chikawa, M.; di Matteo, A.; Fujii, T.; Fujita, K.; Fukushima, M.; Furlich, G.; Goto, T.; Hanlon, W.; Hayashi, M.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Honda, K.; Ikeda, D.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Jeong, H. M.; Jeong, S. M.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kawata, K.; Kido, E.; Kim, H. B.; Kim, J. H.; Kim, J. H.; Kishigami, S.; Kitamura, S.; Kitamura, Y.; Kuzmin, V.; Kuznetsov, M.; Kwon, Y. J.; Lee, K. H.; Lubsandorzhiev, B.; Lundquist, J. P.; Machida, K.; Martens, K.; Matsuyama, T.; Matthews, J. N.; Mayta, R.; Minamino, M.; Mukai, K.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, R.; Nakamura, T.; Nonaka, T.; Oda, H.; Ogio, S.; Ogura, J.; Ohnishi, M.; Ohoka, H.; Okuda, T.; Omura, Y.; Ono, M.; Onogi, R.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sahara, R.; Saito, K.; Saito, Y.; Sakaki, N.; Sakurai, N.; Scott, L. M.; Seki, T.; Sekino, K.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, H. S.; Smith, J. D.; Sokolsky, P.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzawa, T.; Takagi, Y.; Takahashi, Y.; Takamura, M.; Takeda, M.; Takeishi, R.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Uchihori, Y.; Udo, S.; Urban, F.; Wong, T.; Yamamoto, M.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yashiro, K.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zhezher, Y.; Zundel, Z.; Telescope Array Collaboration

2018-05-01

The Telescope Array (TA) observatory utilizes fluorescence detectors and surface detectors (SDs) to observe air showers produced by ultra high energy cosmic rays in Earth’s atmosphere. Cosmic-ray events observed in this way are termed hybrid data. The depth of air shower maximum is related to the mass of the primary particle that generates the shower. This paper reports on shower maxima data collected over 8.5 yr using the Black Rock Mesa and Long Ridge fluorescence detectors in conjunction with the array of SDs. We compare the means and standard deviations of the observed {X}\\max distributions with Monte Carlo {X}\\max distributions of unmixed protons, helium, nitrogen, and iron, all generated using the QGSJet II-04 hadronic model. We also perform an unbinned maximum likelihood test of the observed data, which is subjected to variable systematic shifting of the data {X}\\max distributions to allow us to test the full distributions, and compare them to the Monte Carlo to see which elements are not compatible with the observed data. For all energy bins, QGSJet II-04 protons are found to be compatible with TA hybrid data at the 95% confidence level after some systematic {X}\\max shifting of the data. Three other QGSJet II-04 elements are found to be compatible using the same test procedure in an energy range limited to the highest energies where data statistics are sparse.

Long-term bridge performance high priority bridge performance issues.

DOT National Transportation Integrated Search

2014-10-01

Bridge performance is a multifaceted issue involving performance of materials and protective systems, : performance of individual components of the bridge, and performance of the structural system as a whole. The : Long-Term Bridge Performance (LTBP)...

JSC Director's Discretionary Fund 1992 Annual Report

NASA Technical Reports Server (NTRS)

Jenkins, Lyle (Compiler)

1993-01-01

Annual report of the Johnson Space Center Director's Discretionary Fund documenting effective use of resources. The $1,694,000 funding for FY92 was distributed among 27 projects. The projects are an overall aid to the NASA mission, as well as providing development opportunities for the science and engineering staff with eventual spinoff to commercial uses. Projects described include space-based medical research such as the use of stable isotopes of deuterium and oxygen to measure crew energy use and techniques for noninvasive motion sickness medication. Recycling essentials for space crew support is conducted in the Regenerative Life Support and the Hybrid Regenerative Water Recovery test beds. Two-phase fluid flow simulated under low-gravity conditions, hypervelocity particle impact on open mesh bumpers, and microcalorimetry to measure the long-term hydrazine/material compatibility were investigated. A patent application was made on a shape-memory-alloy release nut. Computer estimate of crew accommodations for advanced concepts was demonstrated. Training techniques were evaluated using multimedia and virtual environment. Upgrades of an electronic still camera provide high resolution images from orbit are presented.

Long-term release of antibiotics by carbon nanotube-coated titanium alloy surfaces diminish biofilm formation by Staphylococcus epidermidis.

PubMed

Hirschfeld, Josefine; Akinoglu, Eser M; Wirtz, Dieter C; Hoerauf, Achim; Bekeredjian-Ding, Isabelle; Jepsen, Søren; Haddouti, El-Mustapha; Limmer, Andreas; Giersig, Michael

2017-05-01

Bacterial biofilms cause a considerable amount of prosthetic joint infections every year, resulting in morbidity and expensive revision surgery. To address this problem, surface modifications of implant materials such as carbon nanotube (CNT) coatings have been investigated in the past years. CNTs are biologically compatible and can be utilized as drug delivery systems. In this study, multi-walled carbon nanotube (MWCNT) coated TiAl6V4 titanium alloy discs were fabricated and impregnated with Rifampicin, and tested for their ability to prevent biofilm formation over a period of ten days. Agar plate-based assays were employed to assess the antimicrobial activity of these surfaces against Staphylococcus epidermidis. It was shown that vertically aligned MWCNTs were more stable against attrition on rough surfaces than on polished TiAl6V4 surfaces. Discs with coated surfaces caused a significant inhibition of biofilm formation for up to five days. Therefore, MWCNT-modified surfaces may be effective against pathogenic biofilm formation on endoprostheses. Copyright © 2017 Elsevier Inc. All rights reserved.

Debonding damage analysis in composite-masonry strengthening systems with polymer- and mortar-based matrix by means of the acoustic emission technique

NASA Astrophysics Data System (ADS)

Verstrynge, E.; Wevers, M.; Ghiassi, B.; Lourenço, P. B.

2016-01-01

Different types of strengthening systems, based on fiber reinforced materials, are under investigation for external strengthening of historic masonry structures. A full characterization of the bond behavior and of the short- and long-term failure mechanisms is crucial to ensure effective design, compatibility with the historic substrate and durability of the strengthening solution. Therein, non-destructive techniques are essential for bond characterization, durability assessment and on-site condition monitoring. In this paper, the acoustic emission (AE) technique is evaluated for debonding characterization and localization on fiber reinforced polymer (FRP) and steel reinforced grout-strengthened clay bricks. Both types of strengthening systems are subjected to accelerated ageing tests under thermal cycles and to single-lap shear bond tests. During the reported experimental campaign, AE data from the accelerated ageing tests demonstrated the thermal incompatibility between brick and epoxy-bonded FRP composites, and debonding damage was successfully detected, characterized and located. In addition, a qualitative comparison is made with digital image correlation and infrared thermography, in view of efficient on-site debonding detection.

Non-metallic nanomaterials in cancer theranostics: a review of silica- and carbon-based drug delivery systems

PubMed Central

Chen, Yu-Cheng; Huang, Xin-Chun; Luo, Yun-Ling; Chang, Yung-Chen; Hsieh, You-Zung; Hsu, Hsin-Yun

2013-01-01

The rapid development in nanomaterials has brought great opportunities to cancer theranostics, which aims to combine diagnostics and therapy for cancer treatment and thereby improve the healthcare of patients. In this review we focus on the recent progress of several cancer theranostic strategies using mesoporous silica nanoparticles and carbon-based nanomaterials. Silicon and carbon are both group IV elements; they have been the most abundant and significant non-metallic substances in human life. Their intrinsic physical/chemical properties are of critical importance in the fabrication of multifunctional drug delivery systems. Responsive nanocarriers constructed using these nanomaterials have been promising in cancer-specific theranostics during the past decade. In all cases, either a controlled texture or the chemical functionalization is coupled with adaptive properties, such as pH-, light-, redox- and magnetic field- triggered responses. Several studies in cells and mice models have implied their underlying therapeutic efficacy; however, detailed and long-term in vivo clinical evaluations are certainly required to make these bench-made materials compatible in real bedside circumstances. PMID:27877592

Carbon Budgets as a Guide to Deep Decarbonisation

NASA Astrophysics Data System (ADS)

Rogelj, J.

2017-12-01

Halting global mean temperature rise requires a limit on the cumulative amount of net CO2 disposed of in the atmosphere. Remaining within the limits of such carbon budgets over the 21st century will require a profound transformation of how our societies use and produce energy, crops, and materials. To understand the options available to stay within stringent carbon budget constraints, global transformation pathways are being devised with integrated models of the energy-economy-land system. This presentation will look at how the latest insights of such pathways affect carbon budgets. Estimates of carbon budgets compatible with a given temperature limit depend on the anticipated temperature contribution at peak warming of non-CO2 forcers. Integrated transformation pathways allow to understand the projected extend of these contributions, as well as estimate the maximum conceivable rate of emissions reductions over the coming decades. The latter directly informs the lower end of future cumulative CO2 emissions and can thus provide an estimate for minimum peak warming over the 21st century - a measure which can be compared to the ambitious long-term temperature goal of the UNFCCC Paris Agreement.

17 CFR 229.1108 - (Item 1108) Servicers.

Code of Federal Regulations, 2013 CFR

2013-04-01

... charged for such advances and terms of recovery by the servicer of such advances. To the extent material...) State how long the servicer has been servicing assets. Provide, to the extent material, a general... material terms of the servicing agreement and the servicer's duties regarding the asset-backed securities...

17 CFR 229.1108 - (Item 1108) Servicers.

Code of Federal Regulations, 2011 CFR

2011-04-01

... charged for such advances and terms of recovery by the servicer of such advances. To the extent material...) State how long the servicer has been servicing assets. Provide, to the extent material, a general... material terms of the servicing agreement and the servicer's duties regarding the asset-backed securities...

17 CFR 229.1108 - (Item 1108) Servicers.

Code of Federal Regulations, 2014 CFR

2014-04-01

... charged for such advances and terms of recovery by the servicer of such advances. To the extent material...) State how long the servicer has been servicing assets. Provide, to the extent material, a general... material terms of the servicing agreement and the servicer's duties regarding the asset-backed securities...

17 CFR 229.1108 - (Item 1108) Servicers.

Code of Federal Regulations, 2012 CFR

2012-04-01

... charged for such advances and terms of recovery by the servicer of such advances. To the extent material...) State how long the servicer has been servicing assets. Provide, to the extent material, a general... material terms of the servicing agreement and the servicer's duties regarding the asset-backed securities...

Sexual satisfaction, sexual compatibility, and relationship adjustment in couples: the role of sexual behaviors, orgasm, and men's discernment of women's intercourse orgasm.

PubMed

Klapilová, Kateřina; Brody, Stuart; Krejčová, Lucie; Husárová, Barbara; Binter, Jakub

2015-03-01

Research indicated that (i) vaginal orgasm consistency is associated with indices of psychological, intimate relationship, and physiological functioning, and (ii) masturbation is adversely associated with some such measures. The aim of this study was to examine the association of various dyadic and masturbation behavior frequencies and percentage of female orgasms during these activities with: (i) measures of dyadic adjustment; (ii) sexual satisfaction; and (iii) compatibility perceived by both partners. In a sample of 85 Czech long-term couples (aged 20-40; mean relationship length 5.4 years), both partners provided details of recent sexual behaviors and completed sexual satisfaction, Spanier dyadic adjustment, and Hurlbert sexual compatibility measures. Multiple regression analyses were used. The association of sexual behaviors with dyadic adjustment, sexual compatibility, and satisfaction was analyzed. In multivariate analyses, women's dyadic adjustment is independently predicted by greater vaginal orgasm consistency and lower frequency of women's masturbation. For both sexes, sexual compatibility was independently predicted by higher frequency of penile-vaginal intercourse and greater vaginal orgasm consistency. Women's sexual satisfaction score was significantly predicted by greater vaginal orgasm consistency, frequency of partner genital stimulation, and negatively with masturbation. Men's sexual satisfaction score was significantly predicted by greater intercourse frequency and any vaginal orgasm of their female partners. Concordance of partner vaginal orgasm consistency estimates was associated with greater dyadic adjustment. The findings suggest that specifically penile-vaginal intercourse frequency and vaginal orgasm consistency are associated with indices of greater intimate relationship adjustment, satisfaction, and compatibility of both partners, and that women's masturbation is independently inversely associated with measures of dyadic and personal function. Results are discussed in light of previous research and an evolutionary theory of vaginal orgasm. © 2014 International Society for Sexual Medicine.

Does stress enhance or impair memory consolidation?

PubMed

Trammell, Janet P; Clore, Gerald L

2014-01-01

Three experiments examined the hypothesis that stress-induced arousal enhances long-term memory for experiences associated with arousing events. Contrary to expectations, in each experiment exposure to a stressor (arm immersion in ice water) interfered with, rather than enhanced, long-term memory for associated material. Despite varying the stimuli (words, pictures), their emotional value (positive, negative, neutral), the time between learning and stress inductions (0 to 1 minute), and opportunities for post-learning rehearsal, each experiment produced a significant reversal of the hypothesised effect. That is, in each experiment, exposure to a stressor interfered with, rather than enhanced, long-term memory for associated material. We conclude that the relationship between stress and memory consolidation is more bounded than previously believed.

Predictive aging results in radiation environments

NASA Astrophysics Data System (ADS)

Gillen, Kenneth T.; Clough, Roger L.

1993-06-01

We have previously derived a time-temperature-dose rate superposition methodology, which, when applicable, can be used to predict polymer degradation versus dose rate, temperature and exposure time. This methodology results in predictive capabilities at the low dose rates and long time periods appropriate, for instance, to ambient nuclear power plant environments. The methodology was successfully applied to several polymeric cable materials and then verified for two of the materials by comparisons of the model predictions with 12 year, low-dose-rate aging data on these materials from a nuclear environment. In this paper, we provide a more detailed discussion of the methodology and apply it to data obtained on a number of additional nuclear power plant cable insulation (a hypalon, a silicone rubber and two ethylene-tetrafluoroethylenes) and jacket (a hypalon) materials. We then show that the predicted, low-dose-rate results for our materials are in excellent agreement with long-term (7-9 year) low-dose-rate results recently obtained for the same material types actually aged under bnuclear power plant conditions. Based on a combination of the modelling and long-term results, we find indications of reasonably similar degradation responses among several different commercial formulations for each of the following "generic" materials: hypalon, ethylene-tetrafluoroethylene, silicone rubber and PVC. If such "generic" behavior can be further substantiated through modelling and long-term results on additional formulations, predictions of cable life for other commercial materials of the same generic types would be greatly facilitated.

A new dimension in space experimentation

NASA Technical Reports Server (NTRS)

1983-01-01

Space experimentation, cosmic origins, the long-term effects of the space environment on living things, the long-term effects of space environment on materials and hardware, seeds in space, power generation in space, experimentation with crystals, and thermal control are discussed.

Continuous and embedded solutions for SHM of concrete structures using changing electrical potential in self-sensing cement-based composites

NASA Astrophysics Data System (ADS)

Downey, Austin; Garcia-Macias, Enrique; D'Alessandro, Antonella; Laflamme, Simon; Castro-Triguero, Rafael; Ubertini, Filippo

2017-04-01

Interest in the concept of self-sensing structural materials has grown in recent years due to its potential to enable continuous low-cost monitoring of next-generation smart-structures. The development of cement-based smart sensors appears particularly well suited for monitoring applications due to their numerous possible field applications, their ease of use and long-term stability. Additionally, cement-based sensors offer a unique opportunity for structural health monitoring of civil structures because of their compatibility with new or existing infrastructure. Particularly, the addition of conductive carbon nanofillers into a cementitious matrix provides a self-sensing structural material with piezoresistive characteristics sensitive to deformations. The strain-sensing ability is achieved by correlating the external loads with the variation of specific electrical parameters, such as the electrical resistance or impedance. Selection of the correct electrical parameter for measurement to correlate with features of interest is required for the condition assessment task. In this paper, we investigate the potential of using altering electrical potential in cement-based materials doped with carbon nanotubes to measure strain and detect damage in concrete structures. Experimental validation is conducted on small-scale specimens including a steel-reinforced beam of conductive cement paste. Comparisons are made with constant electrical potential and current methods commonly found in the literature. Experimental results demonstrate the ability of the changing electrical potential at detecting features important for assessing the condition of a structure.

Feasibility of pig and human-derived aortic valve interstitial cells seeding on fixative-free decellularized animal pericardium.

PubMed

Santoro, Rosaria; Consolo, Filippo; Spiccia, Marco; Piola, Marco; Kassem, Samer; Prandi, Francesca; Vinci, Maria Cristina; Forti, Elisa; Polvani, Gianluca; Fiore, Gianfranco Beniamino; Soncini, Monica; Pesce, Maurizio

2016-02-01

Glutaraldehyde-fixed pericardium of animal origin is the elective material for the fabrication of bio-prosthetic valves for surgical replacement of insufficient/stenotic cardiac valves. However, the pericardial tissue employed to this aim undergoes severe calcification due to chronic inflammation resulting from a non-complete immunological compatibility of the animal-derived pericardial tissue resulting from failure to remove animal-derived xeno-antigens. In the mid/long-term, this leads to structural deterioration, mechanical failure, and prosthesis leaflets rupture, with consequent need for re-intervention. In the search for novel procedures to maximize biological compatibility of the pericardial tissue into immunocompetent background, we have recently devised a procedure to decellularize the human pericardium as an alternative to fixation with aldehydes. In the present contribution, we used this procedure to derive sheets of decellularized pig pericardium. The decellularized tissue was first tested for the presence of 1,3 α-galactose (αGal), one of the main xenoantigens involved in prosthetic valve rejection, as well as for mechanical tensile behavior and distensibility, and finally seeded with pig- and human-derived aortic valve interstitial cells. We demonstrate that the decellularization procedure removed the αGAL antigen, maintained the mechanical characteristics of the native pig pericardium, and ensured an efficient surface colonization of the tissue by animal- and human-derived aortic valve interstitial cells. This establishes, for the first time, the feasibility of fixative-free pericardial tissue seeding with valve competent cells for derivation of tissue engineered heart valve leaflets. © 2015 Wiley Periodicals, Inc.

Tailoring of TiO2 films by H2SO4 treatment and UV irradiation to improve anticoagulant ability and endothelial cell compatibility.

PubMed

Liao, Yuzhen; Li, Linhua; Chen, Jiang; Yang, Ping; Zhao, Ansha; Sun, Hong; Huang, Nan

2017-07-01

Surfaces with dual functions that simultaneously exhibit good anticoagulant ability and endothelial cell (EC) compatibility are desirable for blood contact materials. However, these dual functions have rarely been achieved by inorganic materials. In this study, titanium dioxide (TiO 2 ) films were treated by sulphuric acid (H 2 SO 4 ) and ultraviolet (UV) irradiation successively (TiO 2 H 2 SO 4 -UV), resulting in good anticoagulant ability and EC compatibility simultaneously. We found that UV irradiation improved the anticoagulant ability of TiO 2 films significantly while enhancing EC compatibility, though not significantly. The enhanced anticoagulant ability could be related to the oxidation of surface-adsorbed hydrocarbons and increased hydrophilicity. The H 2 SO 4 treatment improved the anticoagulant ability of TiO 2 films slightly, while UV irradiation improved the anticoagulant ability strongly. The enhanced EC compatibility could be related to the increased surface roughness and positive charges on the surface of the TiO 2 films. Furthermore, the time-dependent degradation of the enhanced EC compatibility and anticoagulant ability of TiO 2 H 2 SO 4 -UV was observed. In summary, TiO 2 H 2 SO 4 -UV expressed both excellent anticoagulant ability and good EC compatibility at the same time, which could be desirable for blood contact materials. However, the compatibility of TiO 2 H 2 SO 4 -UV with smooth muscle cells (SMCs) and macrophages was also improved. More effort is still needed to selectively improve EC compatibility on TiO 2 films for better re-endothelialization. Copyright © 2017 Elsevier B.V. All rights reserved.

Integrated Data Collection Analysis (IDCA) Program - Mixing Procedures and Materials Compatibility

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

Olinger, Becky D.; Sandstrom, Mary M.; Warner, Kirstin F.

Three mixing procedures have been standardized for the IDCA proficiency test—solid-solid, solid-liquid, and liquid-liquid. Due to the variety of precursors used in formulating the materials for the test, these three mixing methods have been designed to address all combinations of materials. Hand mixing is recommended for quantities less than 10 grams and Jar Mill mixing is recommended for quantities over 10 grams. Consideration must also be given to the type of container used for the mixing due to the wide range of chemical reactivity of the precursors and mixtures. Eight web site sources from container and chemical manufacturers have beenmore » consulted. Compatible materials have been compiled as a resource for selecting containers made of materials stable to the mixtures. In addition, container materials used in practice by the participating laboratories are discussed. Consulting chemical compatibility tables is highly recommended for each operation by each individual engaged in testing the materials in this proficiency test.« less

3D printed cellular solid outperforms traditional stochastic foam in long-term mechanical response

DOE PAGES

Maiti, A.; Small, W.; Lewicki, J.; ...

2016-04-27

3D printing of polymeric foams by direct-ink-write is a recent technological breakthrough that enables the creation of versatile compressible solids with programmable microstructure, customizable shapes, and tunable mechanical response including negative elastic modulus. However, in many applications the success of these 3D printed materials as a viable replacement for traditional stochastic foams critically depends on their mechanical performance and micro-architectural stability while deployed under long-term mechanical strain. To predict the long-term performance of the two types of foams we employed multi-year-long accelerated aging studies under compressive strain followed by a time-temperature-superposition analysis using a minimum-arc-length-based algorithm. The resulting master curvesmore » predict superior long-term performance of the 3D printed foam in terms of two different metrics, i.e., compression set and load retention. To gain deeper understanding, we imaged the microstructure of both foams using X-ray computed tomography, and performed finite-element analysis of the mechanical response within these microstructures. As a result, this indicates a wider stress variation in the stochastic foam with points of more extreme local stress as compared to the 3D printed material, which might explain the latter’s improved long-term stability and mechanical performance.« less

3D printed cellular solid outperforms traditional stochastic foam in long-term mechanical response

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

Maiti, A.; Small, W.; Lewicki, J.

3D printing of polymeric foams by direct-ink-write is a recent technological breakthrough that enables the creation of versatile compressible solids with programmable microstructure, customizable shapes, and tunable mechanical response including negative elastic modulus. However, in many applications the success of these 3D printed materials as a viable replacement for traditional stochastic foams critically depends on their mechanical performance and micro-architectural stability while deployed under long-term mechanical strain. To predict the long-term performance of the two types of foams we employed multi-year-long accelerated aging studies under compressive strain followed by a time-temperature-superposition analysis using a minimum-arc-length-based algorithm. The resulting master curvesmore » predict superior long-term performance of the 3D printed foam in terms of two different metrics, i.e., compression set and load retention. To gain deeper understanding, we imaged the microstructure of both foams using X-ray computed tomography, and performed finite-element analysis of the mechanical response within these microstructures. As a result, this indicates a wider stress variation in the stochastic foam with points of more extreme local stress as compared to the 3D printed material, which might explain the latter’s improved long-term stability and mechanical performance.« less

3D printed cellular solid outperforms traditional stochastic foam in long-term mechanical response

NASA Astrophysics Data System (ADS)

Maiti, A.; Small, W.; Lewicki, J. P.; Weisgraber, T. H.; Duoss, E. B.; Chinn, S. C.; Pearson, M. A.; Spadaccini, C. M.; Maxwell, R. S.; Wilson, T. S.

2016-04-01

3D printing of polymeric foams by direct-ink-write is a recent technological breakthrough that enables the creation of versatile compressible solids with programmable microstructure, customizable shapes, and tunable mechanical response including negative elastic modulus. However, in many applications the success of these 3D printed materials as a viable replacement for traditional stochastic foams critically depends on their mechanical performance and micro-architectural stability while deployed under long-term mechanical strain. To predict the long-term performance of the two types of foams we employed multi-year-long accelerated aging studies under compressive strain followed by a time-temperature-superposition analysis using a minimum-arc-length-based algorithm. The resulting master curves predict superior long-term performance of the 3D printed foam in terms of two different metrics, i.e., compression set and load retention. To gain deeper understanding, we imaged the microstructure of both foams using X-ray computed tomography, and performed finite-element analysis of the mechanical response within these microstructures. This indicates a wider stress variation in the stochastic foam with points of more extreme local stress as compared to the 3D printed material, which might explain the latter’s improved long-term stability and mechanical performance.

3D printed cellular solid outperforms traditional stochastic foam in long-term mechanical response

PubMed Central

Maiti, A.; Small, W.; Lewicki, J. P.; Weisgraber, T. H.; Duoss, E. B.; Chinn, S. C.; Pearson, M. A.; Spadaccini, C. M.; Maxwell, R. S.; Wilson, T. S.

2016-01-01

3D printing of polymeric foams by direct-ink-write is a recent technological breakthrough that enables the creation of versatile compressible solids with programmable microstructure, customizable shapes, and tunable mechanical response including negative elastic modulus. However, in many applications the success of these 3D printed materials as a viable replacement for traditional stochastic foams critically depends on their mechanical performance and micro-architectural stability while deployed under long-term mechanical strain. To predict the long-term performance of the two types of foams we employed multi-year-long accelerated aging studies under compressive strain followed by a time-temperature-superposition analysis using a minimum-arc-length-based algorithm. The resulting master curves predict superior long-term performance of the 3D printed foam in terms of two different metrics, i.e., compression set and load retention. To gain deeper understanding, we imaged the microstructure of both foams using X-ray computed tomography, and performed finite-element analysis of the mechanical response within these microstructures. This indicates a wider stress variation in the stochastic foam with points of more extreme local stress as compared to the 3D printed material, which might explain the latter’s improved long-term stability and mechanical performance. PMID:27117858

Compatibility of refractory materials for nuclear reactor poison control systems

NASA Technical Reports Server (NTRS)

Sinclair, J. H.

1974-01-01

Metal-clad poison rods have been considered for the control system of an advanced space power reactor concept studied at the NASA Lewis Research Center. Such control rods may be required to operate at temperatures of about 140O C. Selected poison materials (including boron carbide and the diborides of zirconium, hafnium, and tantalum) were subjected to 1000-hour screening tests in contact with candidate refractory metal cladding materials (including tungsten and alloys of tantalum, niobium, and molybdenum) to assess the compatibility of these materials combinations at the temperatures of interest. Zirconium and hafnium diborides were compatible with refractory metals at 1400 C, but boron carbide and tantalum diboride reacted with the refractory metals at this temperature. Zirconium diboride also showed promise as a reaction barrier between boron carbide and tungsten.

Central Cross-Talk in Task Switching : Evidence from Manipulating Input-Output Modality Compatibility

ERIC Educational Resources Information Center

Stephan, Denise Nadine; Koch, Iring

2010-01-01

Two experiments examined the role of compatibility of input and output (I-O) modality mappings in task switching. We define I-O modality compatibility in terms of similarity of stimulus modality and modality of response-related sensory consequences. Experiment 1 included switching between 2 compatible tasks (auditory-vocal vs. visual-manual) and…

75 FR 54497 - Ocean Dumping; Guam Ocean Dredged Material Disposal Site Designation

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-08

... of special scientific importance, and other legitimate uses of the ocean. Minor short-term... option available since 1997. EPA determined that there is a long-term need for an ocean disposal site... Guam and surrounding waters. This is based on the long-term need to support the Naval and commercial...

The bioink: A comprehensive review on bioprintable materials.

PubMed

Hospodiuk, Monika; Dey, Madhuri; Sosnoski, Donna; Ozbolat, Ibrahim T

This paper discusses "bioink", bioprintable materials used in three dimensional (3D) bioprinting processes, where cells and other biologics are deposited in a spatially controlled pattern to fabricate living tissues and organs. It presents the first comprehensive review of existing bioink types including hydrogels, cell aggregates, microcarriers and decellularized matrix components used in extrusion-, droplet- and laser-based bioprinting processes. A detailed comparison of these bioink materials is conducted in terms of supporting bioprinting modalities and bioprintability, cell viability and proliferation, biomimicry, resolution, affordability, scalability, practicality, mechanical and structural integrity, bioprinting and post-bioprinting maturation times, tissue fusion and formation post-implantation, degradation characteristics, commercial availability, immune-compatibility, and application areas. The paper then discusses current limitations of bioink materials and presents the future prospects to the reader. Copyright © 2017 Elsevier Inc. All rights reserved.

Advanced subsonic long-haul transport terminal area compatibility study. Volume 1: Compatibility assessment

NASA Technical Reports Server (NTRS)

1974-01-01

An analysis was made to identify airplane research and technology necessary to ensure advanced transport aircraft the capability of accommodating forecast traffic without adverse impact on airport communities. Projections were made of the delay, noise, and emissions impact of future aircraft fleets on typical large urban airport. Design requirements, based on these projections, were developed for an advanced technology, long-haul, subsonic transport. A baseline aircraft was modified to fulfill the design requirements for terminal area compatibility. Technical and economic comparisons were made between these and other aircraft configured to support the study.

Controlled CO2 injection into a shallow aquifer and leakage detection monitoring practices at the K-COSEM site, Korea

NASA Astrophysics Data System (ADS)

Lee, S. S.; Joun, W.; Ju, Y. J.; Ha, S. W.; Jun, S. C.; Lee, K. K.

2017-12-01

Artificial carbon dioxide injection into a shallow aquifer system was performed with two injection types imitating short- and long-term CO2 leakage events into a shallow aquifer. One is pulse type leakage of CO2 (6 hours) under a natural hydraulic gradient (0.02) and the other is long-term continuous injection (30 days) under a forced hydraulic gradient (0.2). Injection and monitoring tests were performed at the K-COSEM site in Eumseong, Korea where a specially designed well field had been installed for artificial CO2 release tests. CO2-infused and tracer gases dissolved groundwater was injected through a well below groundwater table and monitoring were conducted in both saturated and unsaturated zones. Real-time monitoring data on CO2 concentration and hydrochemical parameters, and periodical measurements of several gas tracers (He, Ar, Kr, SF6) were obtained. The pulse type short-term injection test was carried out prior to the long-term injection test. Results of the short-term injection test, under natural hydraulic gradient, showed that CO2 plume migrated along the preferential pathway identified through hydraulic interference tests. On the other hand, results of the long-term injection test indicated the CO2 plume migration path was aligned to the forced hydraulic gradient. Compared to the short-term test, the long-term injection formed detectable CO2 concentration change in unsaturated wellbores. Recovery data of tracer gases made breakthrough curves compatible to numerical simulation results. The monitoring results indicated that detection of CO2 leakage into groundwater was more effectively performed by using a pumping and monitoring method in order to capture by-passing plume. With this concept, an effective real-time monitoring method was proposed. Acknowledgement: Financial support was provided by the "R&D Project on Environmental Management of Geologic CO2storage" from the KEITI (Project number : 2014001810003)

LIPID11: A Modular Framework for Lipid Simulations using Amber

PubMed Central

Skjevik, Åge A.; Madej, Benjamin D.; Walker, Ross C.; eigen, Knut T

2013-01-01

Accurate simulation of complex lipid bilayers has long been a goal in condensed phase molecular dynamics (MD). Structure and function of membrane-bound proteins are highly dependent on the lipid bilayer environment and are challenging to study through experimental methods. Within Amber, there has been limited focus on lipid simulations, although some success has been seen with the use of the General Amber Force Field (GAFF). However, to date there are no dedicated Amber lipid force fields. In this paper we describe a new charge derivation strategy for lipids consistent with the Amber RESP approach, and a new atom and residue naming and type convention. In the first instance, we have combined this approach with GAFF parameters. The result is LIPID11, a flexible, modular framework for the simulation of lipids that is fully compatible with the existing Amber force fields. The charge derivation procedure, capping strategy and nomenclature for LIPID11, along with preliminary simulation results and a discussion of the planned long-term parameter development are presented here. Our findings suggest that Lipid11 is a modular framework feasible for phospholipids and a flexible starting point for the development of a comprehensive, Amber-compatible lipid force field. PMID:22916730

Short-Term and Long-Term Effects of Orthopedic Biodegradable Implants

PubMed Central

Amini, Ami R.; Wallace, James S.; Nukavarapu, Syam P.

2012-01-01

Presently, orthopedic and oral/maxillofacial implants represent a combined $2.8 billion market, a figure expected to experience significant and continued growth. Although traditional permanent implants have been proved clinically efficacious, they are also associated with several drawbacks, including secondary revision and removal surgeries. Non-permanent, biodegradable implants offer a promising alternative for patients, as they provide temporary support and degrade at a rate matching tissue formation, and thus, eliminate the need for secondary surgeries. These implants have been in clinical use for nearly 25 years, competing directly with, or maybe even exceeding, the performance of permanent implants. The initial implantation of biodegradable materials, as with permanent materials, mounts an acute host inflammatory response. Over time, the implant degradation profile and possible degradation product toxicity mediate long-term biodegradable implant-induced inflammation. However, unlike permanent implants, this inflammation is likely to cease once the material disappears. Implant-mediated inflammation is a critical determinant for implant success. Thus, for the development of a proactive biodegradable implant that has the ability to promote optimal bone regeneration and minimal detrimental inflammation, a thorough understanding of short- and long-term inflammatory events is required. Here, we discuss an array of biodegradable orthopedic implants, their associated short- and long- term inflammatory effects, and methods to mediate these inflammatory events. PMID:22043969

Materials compatibility issues related to thermal energy storage for a space solar dynamic power system

NASA Technical Reports Server (NTRS)

Faget, N. M.

1986-01-01

Attention is given to results obtained to date in developmental investigations of a thermal energy storage (TES) system for the projected NASA Space Station's solar dynamic power system; these tests have concentrated on issues related to materials compatibility for phase change materials (PCMs) and their containment vessels' materials. The five PCMs tested have melting temperatures that correspond to the operating temperatures of either the Brayton or Rankine heat engines, which were independently chosen for their high energy densities.

Material Compatibility for Historic Items Decontaminated with ...

EPA Pesticide Factsheets

Report This project continued research of the effects of decontamination methods for biological agents on materials identified as representative of types of irreplaceable objects or works of art found in museums and/or archive settings. In the previous research, surrogate materials were checked for compatibility with four decontamination methods: chlorine dioxide, hydrogen peroxide vapor, methyl bromide, and ethylene oxide gas. This project investigated the effects of gamma irradiation, which has also been shown to be an effective decontamination method for biological agents, on the surrogate test materials.

The evaluation of long-term effects of cinnamon bark and olive leaf on toxicity induced by streptozotocin administration to rats.

PubMed

Onderoglu, S; Sozer, S; Erbil, K M; Ortac, R; Lermioglu, F

1999-11-01

The effects of cinnamon bark and olive leaf have been investigated on streptozotocin-induced tissue injury, and some biochemical and haematological changes in rats. The effects on glycaemia were also evaluated. Long-term administration of olive leaf caused significant improvement in tissue injury induced by streptozotocin treatment; the effect of cinnamon bark was less extent. No effects on blood glucose levels were detected. However, significant decreases in some increased biochemical and haematological parameters of streptozotocin-treated rats were observed. Aspartate aminotransferase, urea and cholesterol levels were significantly decreased by treatment with both plant materials, and alanine aminotransferase by treatment with olive leaf. Cinnamon bark also caused a significant decrease in platelet counts. In addition, any visible toxicity, except decrease in body weight gain, attributable to the long-term use of plant materials was not established in normal rats. The data indicate that long-term use of olive leaf and cinnamon bark may provide benefit against diabetic conditions. Determination of underlying mechanism(s) of beneficial effects, toxicity to other systems and clinical assessments of related plant materials are major topics requiring further studies.

EVAHEART: an implantable centrifugal blood pump for long-term circulatory support.

PubMed

Yamazaki, Kenji; Kihara, Shinichiro; Akimoto, Takehide; Tagusari, Osamu; Kawai, Akihiko; Umezu, Mitsuo; Tomioka, Jun; Kormos, Robert L; Griffith, Bartley P; Kurosawa, Hiromi

2002-11-01

We developed "EVAHEART": a compact centrifugal blood pump system as an implantable left ventricular assist device for long-term circulatory support. The 55 x 64 mm pump is made from pure titanium, and weighs 370 g. The entire blood-contacting surface is covered with an anti-thrombogenic coating of diamond like carbon (DLC) or 2-methacryloyloxyethyl phosphorylcholine (MPC) to improve blood compatibility. Flows exceeding 12 L/min against 100 mmHg pressure at 2600 rpm was measured. A low-temperature mechanical seal with recirculating cooling system is used to seal the shaft. EVAHEART demonstrated an acceptably low hemolysis rate with normalized index of hemolysis of 0.005 +/- 0.002 g/100L. We evaluated the pump in long-term in-vivo experiments with seven calves. Via left thoracotomy, we conducted left ventricular apex-descending aorta bypass, placing the pump in the left thoracic cavity. Pump flow rates was maintained at 5-9 L/min, pump power consumption remained stable at 9-10 W in all cases, plasma free Hb levels were less than 15 mg/dl, and the seal system showed good seal capability throughout the experiments. The calves were sacrificed on schedule on postoperative day 200, 222, 142, 90, 151, 155, and 133. No thrombi formed on the blood contacting surface with either the DLC or MPC coating, and no major organ thromboembolisms occurred except for a few small renal infarcts. EVAHEART centrifugal blood pump demonstrated excellent performance in long-term in-vivo experiments.

Multicore-shell nanofiber architecture of polyimide/polyvinylidene fluoride blend for thermal and long-term stability of lithium ion battery separator.

PubMed

Park, Sejoon; Son, Chung Woo; Lee, Sungho; Kim, Dong Young; Park, Cheolmin; Eom, Kwang Sup; Fuller, Thomas F; Joh, Han-Ik; Jo, Seong Mu

2016-11-11

Li-ion battery, separator, multicoreshell structure, thermal stability, long-term stability. A nanofibrous membrane with multiple cores of polyimide (PI) in the shell of polyvinylidene fluoride (PVdF) was prepared using a facile one-pot electrospinning technique with a single nozzle. Unique multicore-shell (MCS) structure of the electrospun composite fibers was obtained, which resulted from electrospinning a phase-separated polymer composite solution. Multiple PI core fibrils with high molecular orientation were well-embedded across the cross-section and contributed remarkable thermal stabilities to the MCS membrane. Thus, no outbreaks were found in its dimension and ionic resistance up to 200 and 250 °C, respectively. Moreover, the MCS membrane (at ~200 °C), as a lithium ion battery (LIB) separator, showed superior thermal and electrochemical stabilities compared with a widely used commercial separator (~120 °C). The average capacity decay rate of LIB for 500 cycles was calculated to be approximately 0.030 mAh/g/cycle. This value demonstrated exceptional long-term stability compared with commercial LIBs and with two other types (single core-shell and co-electrospun separators incorporating with functionalized TiO 2 ) of PI/PVdF composite separators. The proper architecture and synergy effects of multiple PI nanofibrils as a thermally stable polymer in the PVdF shell as electrolyte compatible polymers are responsible for the superior thermal performance and long-term stability of the LIB.

Multicore-shell nanofiber architecture of polyimide/polyvinylidene fluoride blend for thermal and long-term stability of lithium ion battery separator

PubMed Central

Park, Sejoon; Son, Chung Woo; Lee, Sungho; Kim, Dong Young; Park, Cheolmin; Eom, Kwang Sup; Fuller, Thomas F.; Joh, Han-Ik; Jo, Seong Mu

2016-01-01

Li-ion battery, separator, multicoreshell structure, thermal stability, long-term stability. A nanofibrous membrane with multiple cores of polyimide (PI) in the shell of polyvinylidene fluoride (PVdF) was prepared using a facile one-pot electrospinning technique with a single nozzle. Unique multicore-shell (MCS) structure of the electrospun composite fibers was obtained, which resulted from electrospinning a phase-separated polymer composite solution. Multiple PI core fibrils with high molecular orientation were well-embedded across the cross-section and contributed remarkable thermal stabilities to the MCS membrane. Thus, no outbreaks were found in its dimension and ionic resistance up to 200 and 250 °C, respectively. Moreover, the MCS membrane (at ~200 °C), as a lithium ion battery (LIB) separator, showed superior thermal and electrochemical stabilities compared with a widely used commercial separator (~120 °C). The average capacity decay rate of LIB for 500 cycles was calculated to be approximately 0.030 mAh/g/cycle. This value demonstrated exceptional long-term stability compared with commercial LIBs and with two other types (single core-shell and co-electrospun separators incorporating with functionalized TiO2) of PI/PVdF composite separators. The proper architecture and synergy effects of multiple PI nanofibrils as a thermally stable polymer in the PVdF shell as electrolyte compatible polymers are responsible for the superior thermal performance and long-term stability of the LIB. PMID:27833132

Compatibility of molten salts with advanced solar dynamic receiver materials

NASA Technical Reports Server (NTRS)

Jaworske, D. A.; Perry, W. D.

1989-01-01

Metal-coated graphite fibers are being considered as a thermal conductivity enhancement filler material for molten salts in solar dynamic thermal energy storage systems. The successful metal coating chosen for this application must exhibit acceptable wettability and must be compatible with the molten salt environment. Contact angle values between molten lithium fluoride and several metal, metal fluoride, and metal oxide substrates have been determined at 892 C using a modification of the Wilhelmy plate technique. Reproducible contact angles with repeated exposure to the molten LiF indicated compatibility.

Flammability, Offgassing, and Compatibility Requirements and Test Procedures. Interim NASA Technical Standard

NASA Technical Reports Server (NTRS)

2009-01-01

This Interim Standard establishes requirements for evaluation, testing, and selection of materials that are intended for use in space vehicles, associated Ground Support Equipment (GSE), and facilities used during assembly, test, and flight operations. Included are requirements, criteria, and test methods for evaluating the flammability, offgassing, and compatibility of materials.

Iron-nickel alloys as canister material for radioactive waste disposal in underground repositories

NASA Astrophysics Data System (ADS)

Apps, J. A.

1982-09-01

Canisters containing high-level radioactive waste must retain their integrity in an underground waste repository for at least one thousand years after burial (Nuclear Regulatory Commission, 1981). Since no direct means of verifying canister integrity is plausible over such a long period, indirect methods must be chosen. A persuasive approach is to examine the natural environment and find a suitable material which is thermodynamically compatible with the host rock under the environmental conditions with the host rock under the environmental conditions expected in a waste repository. Several candidates have been proposed, among them being iron-nickel alloys that are known to occur naturally in altered ultramafic rocks. The following review of stability relations among iron-nickel alloys below 3500 C is the initial phase of a more detailed evaluation of these alloys as suitable canister materials.

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

None

Progress is reported on fundamental research in: crystal physics, reactions at metal surfaces, spectroscopy of ionic media, structure of metals, theory of alloying, physical properties, sintering, deformation of crystalline solids, x ray diffraction, metallurgy of superconducting materials, and electron microscope studies. Long-randge applied research studies were conducted for: zirconium metallurgy, materials compatibility, solid reactions, fuel element development, mechanical properties, non-destructive testing, and high-temperature materials. Reactor development support work was carried out for: gas-cooled reactor program, molten-salt reactor, high-flux isotope reactor, space-power program, thorium-utilization program, advanced-test reactor, Army Package Power Reactor, Enrico Fermi fast-breeder reactor, and water desalination program. Other programmore » activities, for which research was conducted, included: thermonuclear project, transuraniunn program, and post-irradiation examination laboratory. Separate abstracts were prepared for 30 sections of the report. (B.O.G.)« less

A new experimental method for the accelerated characterization of composite materials

NASA Technical Reports Server (NTRS)

Brinson, H. F.; Morris, D. H.; Yeow, Y. T.

1978-01-01

A method which permits the prediction of long-term properties of graphite/epoxy laminates on the basis of short-term (15 min) laboratory tests is described. Demonstration of delayed viscoelastic fracture in one laminate configuration, and data on the time and temperature response of a matrix-dominated unidirectional laminate contributed to a characterization of the viscoelastic process in the graphite/epoxy composites. Master curves from short-term tests of certain laminate configurations can be employed to generate long-term master curves. In addition, analytical predictions from short-term results can be used to predict long-term (25-hour) laminate properties.

Coherence time of over a second in a telecom-compatible quantum memory storage material

NASA Astrophysics Data System (ADS)

Rančić, Miloš; Hedges, Morgan P.; Ahlefeldt, Rose L.; Sellars, Matthew J.

2018-01-01

Quantum memories for light will be essential elements in future long-range quantum communication networks. These memories operate by reversibly mapping the quantum state of light onto the quantum transitions of a material system. For networks, the quantum coherence times of these transitions must be long compared to the network transmission times, approximately 100 ms for a global communication network. Due to a lack of a suitable storage material, a quantum memory that operates in the 1,550 nm optical fibre communication band with a storage time greater than 1 μs has not been demonstrated. Here we describe the spin dynamics of 167Er3+: Y2SiO5 in a high magnetic field and demonstrate that this material has the characteristics for a practical quantum memory in the 1,550 nm communication band. We observe a hyperfine coherence time of 1.3 s. We also demonstrate efficient spin pumping of the entire ensemble into a single hyperfine state, a requirement for broadband spin-wave storage. With an absorption of 70 dB cm-1 at 1,538 nm and Λ transitions enabling spin-wave storage, this material is the first candidate identified for an efficient, broadband quantum memory at telecommunication wavelengths.

Long-term behaviors of phosphate-based rapid repairing material for concrete shafts in coal mines.

PubMed

Lei, Feng; Zhen-Ya, Zhang; Xiao-Dong, Wen; Chao, Xin; Dong-Yuan, Hu

2018-04-01

Concrete structures in shaft linings are apt to deteriorate prematurely and therefore prompt restoration is required. In considering this, desulphurization fly ash and machine-made tuff sand are employed to fabricate a phosphate-based rapid repairing material. The long-term efficiency of the material is evaluated based on combined factors, so drying shrinkage, interfacial bonding strength, corrosion resistance, and combustibility of the specimens are tested and researched in this paper. Experimental results showed that, under a dry circumstance, the material goes through a minor expansion at an early stage. It goes into a stage of rapid contraction after one day and a stable contraction after seven days. After 28 days, the total deformation is 67 micro-strains. On the other hand, the fabricated material manifests an excellent mechanical property. The one hour bending strength and compressive strength were 9.2 MPa and 32.6 MPa, respectively. A long-term mine water flushing simulation demonstrates that only 10% bending strength is lost and the corrosion resistance coefficient stays above 0.8, so a very good corrosion resistance is thus achieved. What is more, this repairing material retains its stability even at a high temperature of 1000°C, revealing its good thermo-stability. All these prominent properties make it a good prospective material for real restoration applications.

Boat Hull Blisters: Repair Techniques and Long Term Effects on Hull Degradation

DTIC Science & Technology

1988-08-01

Swelling Stresses Produced by Diffusion; Long Term Damage by Water Absorption ; Effects of Gel Coat on Leaching of Water Soluble Material from...leinforcesents 5. Swelling Stresses Produced by Diffusion 6. Long Term Damage by Water Absorption 7. Effects of Gel Coat on Leaching of Water Soluble...the importance of bilge side water pick-up is emphasized. A second method for preventing blister formation is to eliminate or minimize the water soluble

Deficits in verbal long-term memory and learning in children with poor phonological short-term memory skills.

PubMed

Gathercole, Susan E; Briscoe, Josie; Thorn, Annabel; Tiffany, Claire

2008-03-01

Possible links between phonological short-term memory and both longer term memory and learning in 8-year-old children were investigated in this study. Performance on a range of tests of long-term memory and learning was compared for a group of 16 children with poor phonological short-term memory skills and a comparison group of children of the same age with matched nonverbal reasoning abilities but memory scores in the average range. The low-phonological-memory group were impaired on longer term memory and learning tasks that taxed memory for arbitrary verbal material such as names and nonwords. However, the two groups performed at comparable levels on tasks requiring the retention of visuo-spatial information and of meaningful material and at carrying out prospective memory tasks in which the children were asked to carry out actions at a future point in time. The results are consistent with the view that poor short-term memory function impairs the longer-term retention and ease of learning of novel verbal material.

Numerical simulation of gender differences in a long-term microgravity exposure

NASA Astrophysics Data System (ADS)

Perez-Poch, Antoni

The objective of this work is to analyse and simulate gender differences when individuals are exposed to long-term microgravity. Risk probability of a health impairment which may put in jeopardy a long-term mission is also evaluated. Computer simulations are becoming a promising research line of work, as physiological models become more and more sophisticated and reliable. Technological advances in state-of-the-art hardware technology and software allow nowadays for better and more accurate simulations of complex phenomena, such as the response of the human cardiovascular system to long-term exposure to microgravity. Experimental data for long-term missions are difficult to achieve and reproduce, therefore the predictions of computer simulations are of a major importance in this field. Our approach is based on a previous model developed and implemented in our laboratory (NELME: Numerical Evaluation of Long-term Microgravity Effects). The software simulates the behaviour of the cardiovascular system and different human organs, has a modular architecture, and allows to introduce perturbations such as physical exercise or countermeasures. The implementation is based on a complex electricallike model of this control system, using inexpensive software development frameworks, and has been tested and validated with the available experimental data. Gender differences have been implemented for this specific work, as an adjustment of a number of parameters that are included in the model. Women versus men physiological differences have been therefore taken into account, based upon estimations from the physiology bibliography. A number of simulations have been carried out for long-term exposure to microgravity. Gravity varying from Earth-based to zero, and time exposure are the two main variables involved in the construction of results, including responses to patterns of physical aerobical exercise, and also thermal stress simulating an extra-vehicular activity. Results show that significant differences appear between men and women physiological response after long-term exposure (more than three months) to microgravity. Risk evaluation for every gender, and specific risk thresholds are provided. Initial results are compatible with the existing data, and provide unique information regarding different patterns of microgravity exposure. We conclude that computer-based models such us NELME are a promising line of work to predict health risks in long-term missions. More experimental work is needed to adjust some parameters of the model. This work may be seen as another contribution to a better understanding of the underlying processes involved for both women in man adaptation to long-term microgravity.

On the role of numerical simulations in studies of reduced gravity-induced physiological effects in humans. Results from NELME.

NASA Astrophysics Data System (ADS)

Perez-Poch, Antoni

Computer simulations are becoming a promising research line of work, as physiological models become more and more sophisticated and reliable. Technological advances in state-of-the-art hardware technology and software allow nowadays for better and more accurate simulations of complex phenomena, such as the response of the human cardiovascular system to long-term exposure to microgravity. Experimental data for long-term missions are difficult to achieve and reproduce, therefore the predictions of computer simulations are of a major importance in this field. Our approach is based on a previous model developed and implemented in our laboratory (NELME: Numercial Evaluation of Long-term Microgravity Effects). The software simulates the behaviour of the cardiovascular system and different human organs, has a modular archi-tecture, and allows to introduce perturbations such as physical exercise or countermeasures. The implementation is based on a complex electrical-like model of this control system, using inexpensive development frameworks, and has been tested and validated with the available experimental data. The objective of this work is to analyse and simulate long-term effects and gender differences when individuals are exposed to long-term microgravity. Risk probability of a health impairement which may put in jeopardy a long-term mission is also evaluated. . Gender differences have been implemented for this specific work, as an adjustment of a number of parameters that are included in the model. Women versus men physiological differences have been therefore taken into account, based upon estimations from the physiology bibliography. A number of simulations have been carried out for long-term exposure to microgravity. Gravity varying continuosly from Earth-based to zero, and time exposure are the two main variables involved in the construction of results, including responses to patterns of physical aerobic ex-ercise and thermal stress simulating an extra-vehicular activity. Results show that significant differences appear between men and women physiological response after long-term exposure (more than three months) to microgravity. Risk evaluation for every gender, and specific risk thresholds are provided. Different scenarios like a long-term mission to Moon or Mars are evaluated, including countermeasures such as aerobic exercise. Initial results are compatible with the existing data, and provide useful insights regarding different patterns of microgravity exposure. We conclude that computer-based models such us NELME are a promising line of work to predict health risks in long-term missions.

Does Stress Enhance or Impair Memory Consolidation?

PubMed Central

Trammell, Janet P.; Clore, Gerald L.

2014-01-01

Three experiments examined the hypothesis that stress-induced arousal enhances long term memory for experiences associated with an arousing events. Contrary to expectations, in each experiment exposure to a stressor (arm immersion in ice water) interfered with, rather than enhanced, long term memory for associated material. Despite varying the stimuli (words, pictures), their emotional value (positive, negative, neutral), the time between learning and stress inductions (0 to 1 minute), and opportunities for post-learning rehearsal, each experiment produced a significant reversal of the hypothesized effect. That is, in each experiment, exposure to a stressor interfered with, rather than enhanced, long term memory for associated material. We conclude that the relationship between stress and memory consolidation is more bounded than previously believed. PMID:23895111

Technical reference for the use of the slow crack growth test for modeling and predicting the long-term performance of polyethylene gas pipes. Final report, March 1987-May 1992. Volume 2

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

Kanninen, M.F.; O'Donoghue, P.E.; Popelar, C.F.

1993-02-01

The project was undertaken for the purposes of quantifying the Battelle slow crack growth (SCG) test for predicting long-term performance of polyethylene gas distribution pipes, and of demonstrating the applicability of the methodology for use by the gas industry for accelerated characterization testing, thereby bringing the SCG test development effort to a closure. The work has revealed that the Battelle SCG test, and the linear fracture mechanics interpretation that it currently utilizes, is valid for a class of PE materials. The long-term performance of these materials in various operating conditions can therefore be effectively predicted.

Development of side-chain NLO polymer materials with high electro-optic activity and long-term stability

NASA Astrophysics Data System (ADS)

Huang, Diyun; Parker, Timothy; Guan, Hann Wen; Cong, Shuxin; Jin, Danliang; Dinu, Raluca; Chen, Baoquan; Tolstedt, Don; Wolf, Nick; Condon, Stephen

2005-01-01

The electro-optic coefficient and long-term dipole alignment stability are two major factors in the development of high performance NLO materials for the application of high-speed EO devices. We have developed a high performance non-linear organic chromophore and incorporated it into a crosslinkable side-chain polyimide system. The polymer was synthesized through stepwise grafting of the crosslinker followed by the chromophore onto the polyimide backbone via esterification. Different chromophore loading levels were achieved by adjusting the crosslinker/chromophore feeding ratio. The polyimides films were contact-poled with second-harmonic generation monitoring. A large EO coefficient value was obtained and good long-term thermal stability at 85°C was observed.

Characterization of adhesion at carbon fiber-fluorinated epoxy interface and effect of environmental degradation

NASA Astrophysics Data System (ADS)

Dasgupta, Suman

2011-12-01

Carbon fiber reinforced polymers are excellent candidates for aerospace, automobile and other mobile applications due to their high specific strength and modulus. The most prominent aerospace application of carbon fiber composites in recent times is the Boeing 787 Dreamliner, which is the world's first major commercial airliner to extensively use composite materials. The critical issue, which needs to be addressed hereby, is long-term safety. Hence, long-term durability of composite materials in such applications becomes a point of concern. Conventional polymer matrices, such as thermosetting resins, which are used as matrix material in carbon fiber composites, are susceptible to degradation in the form of chemical corrosion, UV degradation and moisture, in severe environmental conditions. Fluorinated polymers offer a viable alternative as matrix material, due to their reduced susceptibility to environmental degradation. The epoxy system used in this study is fluorinated Tetra-glycidyl methylene di-aniline (6F-TGMDA), which was developed by polymer scientists at NASA Langley Research Center. The hydrophobic nature of this epoxy makes it a potential matrix material in aerospace applications. However, its compatibility in carbon fiber-reinforced composites remains to be investigated. This study aims to characterize the interfacial properties in carbon fiber reinforced fluorinated epoxy composites. Typical interfacial characterization parameters, like interfacial shear strength, estimated from the microbond test, proved to be inadequate in accurately estimating adhesion since it assumes a uniform distribution of stresses along the embedded fiber length. Also, it does not account for any residual stresses present at the interface, which might arise due to thermal expansion differences and Poisson's ratio differences of the fiber and matrix. Hence, an analytical approach, which calculates adhesion pressure at the interface, was adopted. This required determination of the unknown mechanical and physical properties of the resin, the relaxation modulus (determined using nano-indentation) and coefficient of thermal expansion (determined using coherent gradient sensing). The adhesional pressure for 6F TGMDA-carbon fiber interface was found to be 135.48 MPa compared to 138.47 MPa for the Diamino diphenyl sulphone (DDS) cured TGMDA-carbon fiber interface. The fact that the adhesional pressure does not show significant decrease upon fluorination of the epoxy system is an advantage. The hydrophobicity of fluorine can be utilized to manufacture environmentally resistant composites while keeping the level of interfacial adhesion the same as in the case of conventional epoxy system, DDS cured TGMDA.

Interlayer toughening of fiber composite flywheel rotors

DOEpatents

Groves, Scott E.; Deteresa, Steven J.

1998-01-01

An interlayer toughening mechanism to mitigate the growth of damage in fiber composite flywheel rotors for long application. The interlayer toughening mechanism may comprise one or more tough layers composed of high-elongation fibers, high-strength fibers arranged in a woven pattern at a range from 0.degree. to 90.degree. to the rotor axis and bound by a ductile matrix material which adheres to and is compatible with the materials used for the bulk of the rotor. The number and spacing of the tough interlayers is a function of the design requirements and expected lifetime of the rotor. The mechanism has particular application in uninterruptable power supplies, electrical power grid reservoirs, and compulsators for electric guns, as well as electromechanical batteries for vehicles.

Interlayer toughening of fiber composite flywheel rotors

DOEpatents

Groves, S.E.; Deteresa, S.J.

1998-07-14

An interlayer toughening mechanism is described to mitigate the growth of damage in fiber composite flywheel rotors for long application. The interlayer toughening mechanism may comprise one or more tough layers composed of high-elongation fibers, high-strength fibers arranged in a woven pattern at a range from 0{degree} to 90{degree} to the rotor axis and bound by a ductile matrix material which adheres to and is compatible with the materials used for the bulk of the rotor. The number and spacing of the tough interlayers is a function of the design requirements and expected lifetime of the rotor. The mechanism has particular application in uninterruptable power supplies, electrical power grid reservoirs, and compulsators for electric guns, as well as electromechanical batteries for vehicles. 2 figs.

From photons to phonons and back: a THz optical memory in diamond.

PubMed

England, D G; Bustard, P J; Nunn, J; Lausten, R; Sussman, B J

2013-12-13

Optical quantum memories are vital for the scalability of future quantum technologies, enabling long-distance secure communication and local synchronization of quantum components. We demonstrate a THz-bandwidth memory for light using the optical phonon modes of a room temperature diamond. This large bandwidth makes the memory compatible with down-conversion-type photon sources. We demonstrate that four-wave mixing noise in this system is suppressed by material dispersion. The resulting noise floor is just 7×10(-3) photons per pulse, which establishes that the memory is capable of storing single quanta. We investigate the principle sources of noise in this system and demonstrate that high material dispersion can be used to suppress four-wave mixing noise in Λ-type systems.

The ENN project. ENN exploitation plan.

PubMed

Dekena, R; Rehm-Berbenni, C; Seyfried, K

2000-01-01

The objective of the ENN-European Neurologic Network project is to improve knowledge and treatment of sleep disorders, headache and epilepsy. The means to obtain this objective shall be certain software to be distributed to the appropriate users in the medical field and the collection of relevant cases, in order to set up a neurological database. It is intended that the distribution of the above mentioned software and access to the database, will be able to finance research projects in the neurological field. The outcome of the EU funded project have been six prototypes, which need further work in order to establish a system of compatible and linked products. A particular emphasis of this work should be put on making the products as process oriented as possible. At the time being there are already products available in the market, which would be competing with particular ENN prototypes, but there is no set of compatible and linked products, which would be comparable with the intended set of ENN neurological tools. Such set of tools therefore could be a unique selling proposition. Intellectual property rights and legal implications have to be taken into consideration for the marketing of the ENN products. It has to be made sure, that no third party can assert violation of its IPRs and that, a protection of the products can be attained by appropriate application for IPRs. In the legal field in particular the prescriptions of data protection legislation have to be observed e.g. by obtaining the written consent of patients, whose cases are reported. The marketing concept should be set up as a short-term, middle-term, long-term strategy. The short-term strategy should concentrate on carrying out a market validation study at European level and simultaneously the development from prototype to products. The middle-term strategy should be directed towards the market introduction of the ENN products in Europe. The long-term strategy should comprise marketing of the products in all potential markets worldwide. It is very important to create an ENN brand, which means a common label, a common layout and a common user interface.

Advanced composite structural concepts and materials technologies for primary aircraft structures: Advanced material concepts

NASA Technical Reports Server (NTRS)

Lau, Kreisler S. Y.; Landis, Abraham L.; Chow, Andrea W.; Hamlin, Richard D.

1993-01-01

To achieve acceptable performance and long-term durability at elevated temperatures (350 to 600 F) for high-speed transport systems, further improvements of the high-performance matrix materials will be necessary to achieve very long-term (60,000-120,000 service hours) retention of mechanical properties and damage tolerance. This report emphasizes isoimide modification as a complementary technique to semi-interpenetrating polymer networks (SIPN's) to achieve greater processibility, better curing dynamics, and possibly enhanced thermo-mechanical properties in composites. A key result is the demonstration of enhanced processibility of isoimide-modified linear and thermo-setting polyimide systems.

Emergency department management of patients internally contaminated with radioactive material

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

Kazzi, Ziad; Buzzell, Jennifer; Bertelli, Luiz

After a radiation emergency that involves the dispersal of radioactive material, patients can become externally and internally contaminated with one or more radionuclides. Internal contamination can lead to the delivery of harmful ionizing radiation doses to various organs and tissues or the whole body. The clinical consequences can range from acute radiation syndrome (ARS) to the long term development of cancer. Estimating the amount of radioactive material absorbed into the body can guide the management of patients. Treatment includes, in addition to supportive care and long term monitoring, certain medical countermeasures like Prussian blue, Calcium DTPA and Zinc DTPA.

Emergency department management of patients internally contaminated with radioactive material

DOE PAGES

Kazzi, Ziad; Buzzell, Jennifer; Bertelli, Luiz; ...

2014-11-15

After a radiation emergency that involves the dispersal of radioactive material, patients can become externally and internally contaminated with one or more radionuclides. Internal contamination can lead to the delivery of harmful ionizing radiation doses to various organs and tissues or the whole body. The clinical consequences can range from acute radiation syndrome (ARS) to the long term development of cancer. Estimating the amount of radioactive material absorbed into the body can guide the management of patients. Treatment includes, in addition to supportive care and long term monitoring, certain medical countermeasures like Prussian blue, Calcium DTPA and Zinc DTPA.

Toward a laminar-flow-control transport

NASA Technical Reports Server (NTRS)

Sturgeon, R. F.

1978-01-01

Analyses were conducted to define a practical design for an advanced technology laminar flow control (LRC) transport for initial passenger operation in the early 1990's. Mission requirements, appropriate design criteria, and level of technology for the study aircraft were defined. The characteristics of the selected configuration were established, aircraft and LFC subsystems compatible with the mission requirements were defined, and the aircraft was evaluated in terms of fuel efficiency. A wing design integrating the LFC ducting and metering system into advanced composite wing structure was developed, manufacturing procedures for the surface panel design were established, and environmental and structural testing of surface panel components were conducted. Test results revealed a requirement for relatively minor changes in the manufacturing procedures employed, but have shown the general compatibility of both the selected design and the use of composite materials with the requirements of LFC wing surface panels.

Sexually localized expression of pseudo-self compatibility (PSC) in Petunia X hybrida Hort : 2. Stylar inactivation.

PubMed

Dana, M N; Ascher, P D

1986-01-01

A previously identified S-linked stylar-inactivation PSC factor (Flaschenriem and Ascher 1979b) was studied for its location relative to S. Plants exhibiting complete stylar-inactivation PSC were those with higher multigenic PSC background level than plants with only S-linked partial stylar-inactivation PSC. A pollen-mediated pseudo-self compatibility (PMPSC) adjustment factor was offered as a device to focus on stylar-inactivation PSC by removing some male origin, multigenic PSC. The stylar inactivation factor was not tightly linked to S but affected expression of only the allele to which it was linked. A three part interacting association of genetic material governing self incompatibility (SI) is proposed. The parts of S are the SI identity gene, S-specific PSC genes and, finally, PSC genes which are not S-specific in action. The complete association is termed the SI-complex.

Chemical formation of soft metal electrodes for flexible and wearable electronics.

PubMed

Wang, Dongrui; Zhang, Yaokang; Lu, Xi; Ma, Zhijun; Xie, Chuan; Zheng, Zijian

2018-06-18

Flexible and wearable electronics is one major technology after smartphones. It shows remarkable application potential in displays and informatics, robotics, sports, energy harvesting and storage, and medicine. As an indispensable part and the cornerstone of these devices, soft metal electrodes (SMEs) are of great significance. Compared with conventional physical processes such as vacuum thermal deposition and sputtering, chemical approaches for preparing SMEs show significant advantages in terms of scalability, low-cost, and compatibility with the soft materials and substrates used for the devices. This review article provides a detailed overview on how to chemically fabricate SMEs, including the material preparation, fabrication technologies, methods to characterize their key properties, and representative studies on different wearable applications.

Ground support system methodology and architecture

NASA Technical Reports Server (NTRS)

Schoen, P. D.

1991-01-01

A synergistic approach to systems test and support is explored. A building block architecture provides transportability of data, procedures, and knowledge. The synergistic approach also lowers cost and risk for life cycle of a program. The determination of design errors at the earliest phase reduces cost of vehicle ownership. Distributed scaleable architecture is based on industry standards maximizing transparency and maintainability. Autonomous control structure provides for distributed and segmented systems. Control of interfaces maximizes compatibility and reuse, reducing long term program cost. Intelligent data management architecture also reduces analysis time and cost (automation).

Large space erectable structures - building block structures study

NASA Technical Reports Server (NTRS)

Armstrong, W. H.; Skoumal, D. E.; Straayer, J. W.

1977-01-01

A modular planar truss structure and a long slender boom concept identified as building block approaches to construction of large spacecraft configurations are described. The concepts are compatible in weight and volume goals with the Space Transportation System, use standard structural units, and represent high on-orbit productivity in terms of structural area or beam length. Results of structural trade studies involving static and dynamic analyses of a single module and rigid body deployment analyses to assess kinetics and kinematics of automatic deployment of the building block modules are presented.

The fabrication of a programmable via using phase-change material in CMOS-compatible technology.

PubMed

Chen, Kuan-Neng; Krusin-Elbaum, Lia

2010-04-02

We demonstrate an energy-efficient programmable via concept using indirectly heated phase-change material. This via structure has maximum phase-change volume to achieve a minimum on resistance for high performance logic applications. Process development and material investigations for this device structure are reported. The device concept is successfully demonstrated in a standard CMOS-compatible technology capable of multiple cycles between on/off states for reconfigurable applications.

The semantic-similarity effect in children: influence of long-term knowledge on verbal short-term memory.

PubMed

Monnier, Catherine; Bonthoux, Françoise

2011-11-01

The present research was designed to highlight the relation between children's categorical knowledge and their verbal short-term memory (STM) performance. To do this, we manipulated the categorical organization of the words composing lists to be memorized by 5- and 9-year-old children. Three types of word list were drawn up: semantically similar context-dependent (CD) lists, semantically similar context-independent (CI) lists, and semantically dissimilar lists. In line with the procedure used by Poirier and Saint-Aubin (1995), the dissimilar lists were produced using words from the semantically similar lists. Both 5- and 9-year-old children showed better recall for the semantically similar CD lists than they did for the unrelated lists. In the semantic similar CI condition, semantic similarity enhanced immediate serial recall only at age 9 but contributed to item information memory both at ages 5 and 9. These results, which indicate a semantic influence of long-term memory (LTM) on serial recall from age 5, are discussed in the light of current models of STM. Moreover, we suggest that differences between results at 5 and 9 years are compatible with pluralist models of development. ©2011 The British Psychological Society.

Long-Term Effectiveness, under a Mountain Environment, of a Novel Conservation Nanomaterial Applied on Limestone from a Roman Archaeological Site.

PubMed

Elhaddad, Farid; Carrascosa, Luis A M; Mosquera, Maria J

2018-04-28

A novel alkoxysilane-based product was applied on limestone samples from a Roman archaeological site. The study consisted of an initial phase to evaluate site environmental conditions in order to choose the most suitable product type to be applied. The decay that was produced in the site is mainly caused by natural action, with water being the main vehicle for the decay agents. Thus, the effectiveness of an innovative product with hydrophobic/consolidant properties and two commercial products (consolidant and hydrophobic agent) were evaluated on limestone from Acinipo site, under laboratory conditions. Next, the long-term effectiveness of the three products under study was evaluated by the exposure of limestone samples in the archaeological site for a period of three years. Since the recognized incompatibility between alkoxysilanes and pure carbonate stones, the interaction between the products and the limestones was widely investigated. The results that were obtained allow for it to be concluded that the innovative product presents adequate compatibility and adherence to the limestone under study, producing a long-term effective, homogeneous, and continuous coating with a depth of penetration of up to 10 mm. However, the commercial products produced discontinuous aggregates on the limestone surface, did not penetrate into its porous structure and it did not produce long-lasting effects.

San Francisco Bay Long Term Management Strategy for Dredging

EPA Pesticide Factsheets

The San Francisco Bay Long Term Management Strategy (LTMS) is a cooperative effort to develop a new approach to dredging and dredged material disposal in the San Francisco Bay area. The LTMS serves as the Regional Dredging Team for the San Francisco area.

Shifting to Medicaid-Managed Long-Term Care: Are Vulnerable Florida Beneficiaries Properly Informed?

PubMed

Peterson, Lindsay J; Hyer, Kathryn

2016-10-01

To examine and assess the adequacy of informational material provided to Florida long-term care beneficiaries being required to choose a managed care provider as part of a statewide, mandatory shift to Medicaid-managed long-term care (MMLTC). Informational materials provided by the state of Florida to 90,000 Medicaid long-term care beneficiaries via print mailings and a state website were examined using established content, usability, and readability criteria. Overall, the presentation minimized cognitive complexity, but the information was lacking in critical areas, such as providing clear explanations of the change taking place and the significance of beneficiaries' choices, and enabling beneficiaries to assess their own needs and preferences. A key feature of managed care is the users' choice of plans, but amid a significant policy shift toward MMLTC in Florida, vulnerable beneficiaries may not be receiving the information necessary to make choices that best meet their needs. Our analysis offers lessons to other states shifting to MMLTC. © The Author(s) 2015.

Photopatternable low loss polymer dielectric materials for IR metamaterial applications.

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

Rasberry, Roger D.; Sinclair, Michael B.; Lee, Yun-Ju

An overwhelming majority of metamaterial designs that have been proposed thus far rely on the use of metallic resonators to afford properties that are unprecedented in nature. Though well suited for applications at radio and microwave frequencies, metals experience severe ohmic losses at higher frequencies rendering their use at such frequencies impractical. Certainly the future of metamaterials lies in their implementation in the visible and long wavelength infrared (LWIR, 8-12 {micro}m). Thus, alternative design protocols and material components tailored specifically for these frequencies are highly attractive. Herein, we present low permittivity, low permeability polymer dielectric materials that are well suitedmore » substrates for LWIR-metamaterial applications. These materials lack vibrational absorption bands in the 8-12 {micro}m range are 3D fabrication compatible, photopatternable, and high temperature tolerant. Thus, these materials are ideal for fabrication of 3D metamaterial structures operating in the LWIR and can also serve as negative photoresists for contact lithography applications.« less

Predictive aging results for cable materials in nuclear power plants

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

Gillen, K.T.; Clough, R.L.

1990-11-01

In this report, we provide a detailed discussion of methodology of predicting cable degradation versus dose rate, temperature, and exposure time and its application to data obtained on a number of additional nuclear power plant cable insulation (a hypalon, a silicon rubber and two ethylenetetrafluoroethylenes) and jacket (a hypalon) materials. We then show that the predicted, low-dose-rate results for our materials are in excellent agreement with long-term (7 to 9 years), low dose-rate results recently obtained for the same material types actually aged under nuclear power plant conditions. Based on a combination of the modelling and long-term results, we findmore » indications of reasonably similar degradation responses among several different commercial formulations for each of the following generic'' materials: hypalon, ethylenetetrafluoroethylene, silicone rubber and PVC. If such generic'' behavior can be further substantiated through modelling and long-term results on additional formulations, predictions of cable life for other commercial materials of the same generic types would be greatly facilitated. Finally, to aid utilities in their cable life extension decisions, we utilize our modelling results to generate lifetime prediction curves for the materials modelled to data. These curves plot expected material lifetime versus dose rate and temperature down to the levels of interest to nuclear power plant aging. 18 refs., 30 figs., 3 tabs.« less

Results of studying creep and long-term strength of metals at the Institute of Mechanics at the Lomonosov Moscow State University (To Yu. N. Rabotnov's Anniversary)

NASA Astrophysics Data System (ADS)

Lokoshchenko, A. M.

2014-01-01

Basic results of experimental and theoretical research of creep processes and long-term strength of metals obtained by researchers of the Institute of Mechanics at the Lomonosov Moscow State University are presented. These results further develop and refine the kinetic theory of creep and long-duration strength proposed by Yu. N. Rabotnov. Some problems arising in formulating various types of kinetic equations and describing experimental data for materials that can be considered as statically homogeneous materials (in studying the process of deformation and rupture of such materials, there is no need to study the evolution of individual cracks) are considered. The main specific features of metal creep models at constant and variable stresses, in uniaxial and complex stress states, and with allowance for one or two damage parameters are described. Criterial and kinetic approaches used to determine long-term strength under conditions of a complex stress state are considered. Methods of modeling the metal behavior in an aggressive medium are described. A possibility of using these models for solving engineering problems is demonstrated.

Beyond Quarterly Earnings: Preparing the Business Community for Long-term Climate Risks

NASA Astrophysics Data System (ADS)

Carlson, C.; Goldman, G. T.

2014-12-01

The business community stands to be highly impacted by climate change. In both short and long-term timescales, climate change presents material and financial risks to companies in diverse economic sectors. How the private sector accounts for long-term risks while making short-term decisions about operations is a complex challenge. Companies are accountable to shareholders and must report performance to them on a quarterly basis. At the same time, company investors are exposed to long-term climate-related risks and face losses if companies fail to prepare for climate impacts. The US Securities and Exchange Commission (SEC) obligates publicly traded companies to discuss risks that might materially affect their business and since 2010, the agency recommends that companies consider and discuss any significant risks to their business from climate change. Some companies have complied with this guidance and comprehensively analyze potential climate change impacts, yet others fail to consider climate change at all. Such omissions leave companies without plans for addressing future risks and expose investors and the public to potential catastrophic events from climate change impacts. Climate risk projections can inform companies about the vulnerability of their facilities, supply chains, transportation pathways, and other assets. Such projections can help put climate-related risks in terms of material costs for companies and their investors. Focusing on the vulnerability of coastal facilities, we will use climate change impact projections to demonstrate the economic impacts of climate change faced by the private sector. These risks are then compared to company disclosures to the SEC to assess the degree to which companies have considered their vulnerability to climate change. Finally, we will discuss ways that companies can better assess and manage long-term climate risks.

Materials Compatibility Testing in RSRM ODC: Free Cleaner Selection

NASA Technical Reports Server (NTRS)

Keen, Jill M.; Sagers, Neil W.; McCool, Alex (Technical Monitor)

2001-01-01

Government regulations have mandated production phase-outs of a number of solvents, including 1,1,1-trichloroethane, an ozone-depleting chemical (ODC). This solvent was used extensively in the production of the Reusable Solid Rocket Motors (RSRMs) for the Space Shuttle. Many tests have been performed to identify replacement cleaners. One major area of concern in the selection of a new cleaner has been compatibility. Some specific areas considered included cleaner compatibility with non-metallic surfaces, painted surfaces, support materials such as gloves and wipers as well as corrosive properties of the cleaners on the alloys used on these motors. The intent of this paper is to summarize the test logic, methodology, and results acquired from testing the many cleaner and material combinations.

Effect of long-term exposure to Low Earth Orbit (LEO) space environment

NASA Technical Reports Server (NTRS)

Zimcik, D. G.

1987-01-01

Data obtained from components and materials from the Solar Maximum Mission satellite are presented and compared to data for similar materials obtained from the Advanced Composite Materials Exposure to Space Experiment (ACOMEX) flown on Shuttle mission STS-41G. In addition to evaluation of surface erosion and mass loss that may be of importance to very long-term missions, comparisons of solar absorptance and thermal emittance measurements for both long and short term exposures were made. Although the ratio of absorptance over emittance can be altered by proper choice of materials to ensure a proper operating environment for the spacecraft, once the thermal design is established, it is important that the material properties not change in order to maintain the operating environment for many payload and bus items such as electronics, batteries, fuel, etc. However, data presented show significant changes after short exposure in low Earth environment. Moreover, the measured changes are shown to differ according to the manner of exposure, i.e., normal or oblique, which also affects the resultant eroded surface morphology. These results identify constraints to be considered in development of flight experiments or laboratory testing.

Moving to Aqueous Binder: A Valid Approach to Achieving High‐Rate Capability and Long‐Term Durability for Sodium‐Ion Battery

PubMed Central

Zhao, Jing; Yang, Xu; Yao, Ye; Gao, Yu; Sui, Yongming; Zou, Bo; Ehrenberg, Helmut; Chen, Gang

2018-01-01

Abstract Polyanionic Na3V2(PO4)2F3 with a NASICON‐type structure is heralded as a promising cathode material for sodium‐ion batteries due to its fast ionic conduction, high working voltage, and favorable structural stability. However, a number of challenging issues remain regarding its rate capability and cycle life, which must be addressed to enable greater application compatibility. Here, a facile and effective approach that can be used to overcome these disadvantages by introducing an aqueous carboxymethyl cellulose (CMC) binder is reported. The resulting conductive network serves to accelerate the diffusion of Na+ ions across the interface as well as in the bulk. The strong binding force of the CMC and stable solid permeable interface protect the electrode from degradation, leading to an excellent capacity of 75 mA h g−1 at an ultrahigh rate of 70 C (1 C = 128 mA g−1) and a long lifespan of 3500 cycles at 30 C while sustaining 79% of the initial capacity value. A full cell based on this electrode material delivers an impressive energy density as high as 216 W h kg−1, indicating the potential for application of this straightforward and cost‐effective route for the future development of advanced battery technologies. PMID:29721423

Understanding the interdiffusion behavior and determining the long term stability of tungsten fiber reinforced niobium-base matrix composite systems

NASA Technical Reports Server (NTRS)

Tien, John K.

1990-01-01

The long term interdiffusional stability of tungsten fiber reinforced niobium alloy composites is addressed. The matrix alloy that is most promising for use as a high temperature structural material for reliable long-term space power generation is Nb1Zr. As an ancillary project to this program, efforts were made to assess the nature and kinetics of interphase reaction between selected beryllide intermetallics and nickel and iron aluminides.

On Software Compatibility.

ERIC Educational Resources Information Center

Ershov, Andrei P.

The problem of compatibility of software hampers the development of computer application. One solution lies in standardization of languages, terms, peripherais, operating systems and computer characteristics. (AB)

Proceedings of the Symposium on Long-Life Hardware for Space

NASA Technical Reports Server (NTRS)

1970-01-01

Two-volume edition of the papers of the symposium is described. It is divided into six sections - parts, materials, management, system testing, component design, and system test. Material presented focuses attention on problems created by the increased complexity of technology and long-term mission requirements.

Tapping Resources in Municipal Solid Waste

ERIC Educational Resources Information Center

Blum, S. L.

1976-01-01

Municipal solid waste disposal is becoming complex as costs, wastes, and environmental restrictions increase. Recovery and recycling of materials presents problems of financing, ownership, and operation, technology, and marketing. Energy and materials recovery offers long-term economic and environmental incentives in terms of growing shortages and…

[Cointegration test and variance decomposition for the relationship between economy and environment based on material flow analysis in Tangshan City Hebei China].

PubMed

2015-12-01

The material flow account of Tangshan City was established by material flow analysis (MFA) method to analyze the periodical characteristics of material input and output in the operation of economy-environment system, and the impact of material input and output intensities on economic development. Using econometric model, the long-term interaction mechanism and relationship among the indexes of gross domestic product (GDP) , direct material input (DMI), domestic processed output (DPO) were investigated after unit root hypothesis test, Johansen cointegration test, vector error correction model, impulse response function and variance decomposition. The results showed that during 1992-2011, DMI and DPO both increased, and the growth rate of DMI was higher than that of DPO. The input intensity of DMI increased, while the intensity of DPO fell in volatility. Long-term stable cointegration relationship existed between GDP, DMI and DPO. Their interaction relationship showed a trend from fluctuation to gradual ste adiness. DMI and DPO had strong, positive impacts on economic development in short-term, but the economy-environment system gradually weakened these effects by short-term dynamically adjusting indicators inside and outside of the system. Ultimately, the system showed a long-term equilibrium relationship. The effect of economic scale on economy was gradually increasing. After decomposing the contribution of each index to GDP, it was found that DMI's contribution grew, GDP's contribution declined, DPO's contribution changed little. On the whole, the economic development of Tangshan City has followed the traditional production path of resource-based city, mostly depending on the material input which caused high energy consumption and serous environmental pollution.

Chemical compatibility of cartridge materials

NASA Technical Reports Server (NTRS)

Wilcox, Roy C.; Zee, R. H.

1991-01-01

This twelve month progress report deals with the chemical compatibility of semiconductor crystals grown in zero gravity. Specifically, it studies the chemical compatibility between TZM, a molybdenum alloy containing titanium and zirconium, and WC 103, a titanium alloy containing Niobium and Hafnium, and Gallium arsenide (GaAs) and Cadmium Zinc Tellurite (CdZnTe). Due to the health hazards involved, three approaches were used to study the chemical compatibility between the semiconductor and cartridge materials: reaction retort, thermogravimetric analysis, and bulk cylindrical cartridge containers. A scanning electron microscope with an energy dispersive X-ray analyzer was used to examine all samples after testing. The first conclusion drawn is that reaction rates with TZM were not nearly as great as they were with WC 103. Second, the total reaction between GaAs and WC 103 was almost twice that with TZM. Therefore, even though WC 103 is easier to fabricate, at least half of the cartridge thickness will be degraded if contact is made with one of the semiconductor materials leading to a loss of strength properties.

Guide for Oxygen Compatibility Assessments on Oxygen Components and Systems

NASA Technical Reports Server (NTRS)

Rosales, Keisa R.; Shoffstall, Michael S.; Stoltzfus, Joel M.

2007-01-01

Understanding and preventing fire hazards is necessary when designing, maintaining, and operating oxygen systems. Ignition risks can be minimized by controlling heat sources and using materials that will not ignite or will not support burning in the end-use environment. Because certain materials are more susceptible to ignition in oxygen-enriched environments, a compatibility assessment should be performed before the component is introduced into an oxygen system. This document provides an overview of oxygen fire hazards and procedures that are consistent with the latest versions of American Society for Testing and Materials (ASTM) Standards G63 (1999) and G94 (2005) to address fire hazards associated with oxygen systems. This document supersedes the previous edition, NASA Technical Memorandum 104823, Guide for Oxygen Hazards Analyses on Components and Systems (1996). The step-by-step oxygen compatibility assessment method described herein (see Section 4) enables oxygen-system designers, system engineers, and facility managers to determine areas of concern with respect to oxygen compatibility and, ultimately, prevent damage to a system or injury to personnel.

Compatibility testing of vacuum seal materials

NASA Astrophysics Data System (ADS)

Foster, P. A.; Rodin, W. A.

1993-05-01

Small scale materials compatibility testing was conducted for three elastomers considered for use as vacuum seal materials: Adiprene MOCA-cured; Adiprene Cyanacured; and Sylgard silastic rubber. The tests were conducted using orthogonal array designed experiments for each of the elastomers placed in contact with three materials commonly used during weapon disassembly operations: Duxseal, Sylgard 186 grease, and 2-propyl alcohol. The test results indicated that only the 2-propyl alcohol had a significant effect on the elastomer hardness and physical properties. The alcohol had the largest effect on the two Adiprene materials, and the silastic rubber was the least affected.

Applications of Shape Memory Alloys for Neurology and Neuromuscular Rehabilitation

PubMed Central

Pittaccio, Simone; Garavaglia, Lorenzo; Ceriotti, Carlo; Passaretti, Francesca

2015-01-01

Shape memory alloys (SMAs) are a very promising class of metallic materials that display interesting nonlinear properties, such as pseudoelasticity (PE), shape memory effect (SME) and damping capacity, due to high mechanical hysteresis and internal friction. Our group has applied SMA in the field of neuromuscular rehabilitation, designing some new devices based on the mentioned SMA properties: in particular, a new type of orthosis for spastic limb repositioning, which allows residual voluntary movement of the impaired limb and has no predetermined final target position, but follows and supports muscular elongation in a dynamic and compliant way. Considering patients in the sub-acute phase after a neurological lesion, and possibly bedridden, the paper presents a mobiliser for the ankle joint, which is designed exploiting the SME to provide passive exercise to the paretic lower limb. Two different SMA-based applications in the field of neuroscience are then presented, a guide and a limb mobiliser specially designed to be compatible with diagnostic instrumentations that impose rigid constraints in terms of electromagnetic compatibility and noise distortion. Finally, the paper discusses possible uses of these materials in the treatment of movement disorders, such as dystonia or hyperkinesia, where their dynamic characteristics can be advantageous. PMID:26023790

Modeling of Slot Waveguide Sensors Based on Polymeric Materials

PubMed Central

Bettotti, Paolo; Pitanti, Alessandro; Rigo, Eveline; De Leonardis, Francesco; Passaro, Vittorio M. N.; Pavesi, Lorenzo

2011-01-01

Slot waveguides are very promising for optical sensing applications because of their peculiar spatial mode profile. In this paper we have carried out a detailed analysis of mode confinement properties in slot waveguides realized in very low refractive index materials. We show that the sensitivity of a slot waveguide is not directly related to the refractive index contrast of high and low materials forming the waveguide. Thus, a careful design of the structures allows the realization of high sensitivity devices even in very low refractive index materials (e.g., polymers) to be achieved. Advantages of low index dielectrics in terms of cost, functionalization and ease of fabrication are discussed while keeping both CMOS compatibility and integrable design schemes. Finally, applications of low index slot waveguides as substitute of bulky fiber capillary sensors or in ring resonator architectures are addressed. Theoretical results of this work are relevant to well established polymer technologies. PMID:22164020

Prediction of drug-packaging interactions via molecular dynamics (MD) simulations.

PubMed

Feenstra, Peter; Brunsteiner, Michael; Khinast, Johannes

2012-07-15

The interaction between packaging materials and drug products is an important issue for the pharmaceutical industry, since during manufacturing, processing and storage a drug product is continuously exposed to various packaging materials. The experimental investigation of a great variety of different packaging material-drug product combinations in terms of efficacy and safety can be a costly and time-consuming task. In our work we used molecular dynamics (MD) simulations in order to evaluate the applicability of such methods to pre-screening of the packaging material-solute compatibility. The solvation free energy and the free energy of adsorption of diverse solute/solvent/solid systems were estimated. The results of our simulations agree with experimental values previously published in the literature, which indicates that the methods in question can be used to semi-quantitatively reproduce the solid-liquid interactions of the investigated systems. Copyright © 2012 Elsevier B.V. All rights reserved.

A study of surface tension driven segregation in monotectic alloy systems

NASA Technical Reports Server (NTRS)

Andrews, J. Barry; Andrews, Rosalia N.; Gowens, Terrell F.

1988-01-01

The compatibilities of various monotectic alloy systems with several different crucible materials were evaluated. The study was carried out using small candidate alloy samples of compositions that produced fifty volume percent of each liquid phase at the monotectic temperature. Compatibility was based on the evaluation of the wetting tendency of the two immiscible phases with the crucible material in a one-g solidified sample. Three types of wetting phenomena were observed during the evaluation. Type 1 indicates an alloy-crucible combination where the L2 phase preferentially wets the crucible material. Since L2 is usually the minority phase in desirable alloys, this material combination would be difficult to process and is therefore considered incompatible. Type 2 behavior indicates an alloy-crucible combination where the L1 phase preferentially wets the crucible material. This type of combination is considered compatible since surface tension effects should aid in processing the alloy to a useful form. Type 3 indicates any combination that leads to major reactions between the alloy and crucible material, gas entrapment, or separation of the metal from the crucible wall. Additional compatibility evaluations would have to be carried out on combinations of this category. The five alloy systems studied included aluminum-bismuth, copper-lead, aluminum-indium, aluminum-lead and cadmium-gallium. The systems were combined with crucibles of alumina, boron nitride, mullite, quartz, silicon carbide and zirconia.

Blood compatibility--a perspective.

PubMed

Ratner, B D

2000-01-01

This perspective on blood- materials interactions is intended to introduce the set of papers stemming from the symposium, "Devices and Diagnostics in Contact with Blood: Issues in Blood Compatibility at the Close of the 20th Century," organized on August 4-6, 1999 at the University of Washington by the University of Washington Engineered Biomaterials (UWEB) Engineering Research Center. This article outlines some of the history of blood contacting materials, overviews the work that has originated at the University of Washington over the past 28 years, speculates on the origins of the controversies on blood compatibility and considers the issues that should be addressed in future studies.

Centennial impacts of fragmentation on the canopy structure of tropical montane forest

Treesearch

Nicholas Vaughn; Greg Asner; Christian Giardina

2014-01-01

Fragmentation poses one of the greatest threats to tropical forests with short-term changes to the structure of forest canopies affecting microclimate, tree mortality, and growth. Yet the long-term effects of fragmentation are poorly understood because (1) most effects require many decades to materialize, but long-term studies are very rare, (2) the effects of edges on...

77 FR 46058 - Utility Scale Wind Towers From the Socialist Republic of Vietnam: Preliminary Determination of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-02

... Sale, Comment 1. Sales during the POI were made pursuant to long-term contracts, and/or purchase orders..., the material terms appear to be fixed, pursuant to the long-term agreement, and are reflected in the...: Dynamic Random Access Memory Semiconductors of One Megabit and Above From the Republic of Korea, 57 FR...

Photothermal characterization of encapsulant materials for photovoltaic modules

NASA Technical Reports Server (NTRS)

Liang, R. H.; Gupta, A.; Distefano, S.

1982-01-01

A photothermal test matrix and a low cost testing apparatus for encapsulant materials of photovoltaic modules were defined. Photothermal studies were conducted to screen and rank existing as well as future encapsulant candidate materials and/or material formulations in terms of their long term physiochemical stability under accelerated photothermal aging conditions. Photothermal characterization of six candidate pottant materials and six candidate outer cover materials were carried out. Principal products of photothermal degradation are identified. Certain critical properties are also monitored as a function of photothermal aging.

Investigation of the Behavior of Hardening Masonry Exposed to Variable Stresses

PubMed Central

Šlivinskas, Tomas; Jonaitis, Bronius; Marčiukaitis, Jonas Gediminas

2018-01-01

This paper analyzes the behavior of masonry under variable loads during execution (construction stage). It specifies the creep coefficient for calcium silicate brick masonry, presenting the research data of masonry deformation under variable and constant long-term loads. The interaction of separate layers of composite material in masonry is introduced and the formulae for determining long-term deformations are offered. The research results of masonry’s compressive strength and deformation properties under variable and constant long-term loads are presented. These are then compared to calculated ones. According to the presented comparison, the calculated long-term deformations coincide quite well with those determined experimentally. PMID:29710802

Investigation of the Behavior of Hardening Masonry Exposed to Variable Stresses.

PubMed

Šlivinskas, Tomas; Jonaitis, Bronius; Marčiukaitis, Jonas Gediminas; Zavalis, Robertas

2018-04-28

This paper analyzes the behavior of masonry under variable loads during execution (construction stage). It specifies the creep coefficient for calcium silicate brick masonry, presenting the research data of masonry deformation under variable and constant long-term loads. The interaction of separate layers of composite material in masonry is introduced and the formulae for determining long-term deformations are offered. The research results of masonry’s compressive strength and deformation properties under variable and constant long-term loads are presented. These are then compared to calculated ones. According to the presented comparison, the calculated long-term deformations coincide quite well with those determined experimentally.

Seal Materials Compatible with the Electroplating Solvent Used in Constellation-X Mirrors

NASA Technical Reports Server (NTRS)

Pei, Xiong-Skiba

1999-01-01

The existing gasket seals used in electroplating of the Constellation-X mirrors are difficult to assemble, and the current seal material is hydrophobic and too thick. The combination of the above problems result in: 1) non-uniform plating; 2) defect sites such as pits on the mirror edges; 3) "bear claws" on the edges of the mandrels and mirrors causing difficulties in shell-mirror separations; and 4) leakage of the plating solution past the seals into the mandrel causing chemical etching of the mandrel interior. This paper reports the results of this summer study in searching for alternate seal materials chemically compatible with the electroplating solvent. Fifteen common elastomeric rubber seal materials made-by Parker Seals were investigated including butyl, ethylene propylene, fluorosilicone, nitrile, Viton fluorocarbon, and silicone. Test results showed that Viton fluorocarbon compounds as a group were superior to the other tested compounds for chemical compatibility with the plating bath.

Atmospheric-Pressure-Spray, Chemical- Vapor-Deposited Thin-Film Materials Being Developed for High Power-to- Weight-Ratio Space Photovoltaic Applications

NASA Technical Reports Server (NTRS)

Hepp, Aloysius F.; Harris, Jerry D.; Raffaelle, Ryne P.; Banger, Kulbinder K.; Smith, Mark A.; Cowen, Jonathan E.

2001-01-01

The key to achieving high specific power (watts per kilogram) space photovoltaic arrays is the development of high-efficiency thin-film solar cells that are fabricated on lightweight, space-qualified substrates such as Kapton (DuPont) or another polymer film. Cell efficiencies of 20 percent air mass zero (AM0) are required. One of the major obstacles to developing lightweight, flexible, thin-film solar cells is the unavailability of lightweight substrate or superstrate materials that are compatible with current deposition techniques. There are two solutions for working around this problem: (1) develop new substrate or superstrate materials that are compatible with current deposition techniques, or (2) develop new deposition techniques that are compatible with existing materials. The NASA Glenn Research Center has been focusing on the latter approach and has been developing a deposition technique for depositing thin-film absorbers at temperatures below 400 C.

Compatibility of structural materials with liquid bismuth, lead, and mercury

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

Weeks, J.R.

1996-06-01

During the 1950s and 1960s, a substantial program existed at Brookhaven National Laboratory as part of the Liquid Metal Fuel reactor program on the compatibility of bismuth, lead, and their alloys with structural materials. Subsequently, compatibility investigations of mercury with structural materials were performed in support of development of Rankine cycle mercury turbines for nuclear applications. The present talk will review present understanding of the corrosion/mass-transfer reactions of structural materials with these liquid metal coolants. Topics to be discussed include the basic solubility relationships of iron, chromium, nickel, and refractory metals in these liquid metals, the results of inhibition studies,more » the role of oxygen on the corrosion processes, and specialized topics such as cavitation-corrosion and liquid metal embrittlement. Emphasis will be placed on utilizing the understanding gained in this earlier work on the development of heavy liquid metal targets in spallation neutron sources.« less

Is Cu a stable electrode material in hybrid perovskite solar cells for a 30-year lifetime?

DOE PAGES

Zhao, Jingjing; Zheng, Xiaopeng; Deng, Yehao; ...

2016-10-28

One grand challenge for long-lived perovskite solar cells is that the common electrode materials in solar cells, such as silver and aluminum or even gold, strongly react with hybrid perovskites. Here we report the evaluation of the potential of copper (Cu) as the electrode material in perovskite solar cells for long-term stability. In encapsulated devices which limit exposure to oxygen and moisture, Cu in direct contact with CH 3NH 3PbI 3 showed no reaction at laboratory time scales, and is predicted to be stable for almost 170 years at room temperature and over 22 years at the nominal operating cellmore » temperature of 40 °C. No diffusion of Cu into CH 3NH 3PbI 3 has been observed after thermal annealing for over 100 hours at 80 °C, nor does Cu cause charge trap states in direct contact with CH 3NH 3PbI 3 after long-term thermal annealing or illumination. High performance devices with efficiency above 20% with Cu electrode retains 98% of the initial efficiency after 816 hours storage in ambient environment without encapsulation. Finally, the results indicate Cu is a promising low-cost electrode material for perovskite solar cells for long-term operation.« less

Trace-gas Spectroscopy of Methane on a Silicon Photonic Chip

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

Zhang, Eric; Xiong, Chi; Martin, Yves

Recent advances in hybrid integrated silicon photonic (SiPh) technologies are enabling the migration of conventional free-space optical spectroscopic sensors onto a compact on-chip platform [1-3]. In addition to the small spatial footprint and power efficiency, we envision such sensors to be scalably manufactured using existing CMOS-compatible foundry processes, thus providing disruptive SWaP-C (size, weight, power, and cost) benefits in contrast to commercially available optical sensors. Initial demonstration of evanescent TDLAS (tunable diode laser absorption spectroscopy) of methane (CH4) on a passive SiPh waveguide has indicated minimum fractional absorption of (αL)min = 3.3×10-5 Hz-1/2, which is on-par with state-of-art open-path TDLASmore » sensor systems [4]. Given the general recent movement toward cleaner fuels, CH4 fugitive emissions monitoring is of significant interest given the extremely high radiative forcing potential [5]. For a nominal waveguide length of 30 cm with Γ = 25 % evanescent exposure, this corresponds to ~ 10 ppmv detection sensitivity at 1 s integration time, and further sensitivity enhancement is expected with even longer waveguides, as the laser RIN typically dominates our measurements at nominal waveguide lengths. Despite the excellent sensitivities for short-term integration periods, long-term measurements (> 10 s) are potentially limited on a silicon platform due to the high material thermo-optic coefficient, resulting in significant susceptibility of Fabry-Perot etalons to drift in the presence of even small (~ 1 mK) thermal fluctuations. To this end, customized spectral fitting algorithms have played a significant role in both fringe drift mitigation and peak detection fidelity (e.g. in the presence of a passing CH4 plume), which are crucial for enhancing long-term stability without the need for frequent sensor recalibration. A variety of spectral algorithms have been designed for this purpose, and details will be presented at the meeting.« less

Compatibility Testing of Non-Metallic Materials for the Urine Processor Assembly (UPA) of International Space Station (ISS)

NASA Technical Reports Server (NTRS)

Wingard, Charles Doug; Munafo, Paul M. (Technical Monitor)

2001-01-01

In the International Space Station (ISS), astronauts will convert urine into potable water with the Urine Processor Assembly (UPA). The urine is distilled, with the concentrated form containing about 15% brine solids, and the dilute form as a blend of pre-treated urine/wastewater. Eighteen candidate non-metallic materials for use with the UPA were tested in 2000 for compatibility with the concentrated and dilute urine solutions for continuous times of at least 30 days, and at conditions of 0.5 psia pressure and 100 F, to simulate the working UPA environment. A primary screening test for each material (virgin and conditioned) was dynamic mechanical analysis (DMA) in the stress relaxation mode, with the test data used to predict material performance for a 10-year use in space. Data showed that most of the candidate materials passed the compatibility testing, although a few significant changes in stress relaxation modulus were observed.

Stimulus-response compatibility and psychological refractory period effects: implications for response selection

NASA Technical Reports Server (NTRS)

Lien, Mei-Ching; Proctor, Robert W.

2002-01-01

The purpose of this paper was to provide insight into the nature of response selection by reviewing the literature on stimulus-response compatibility (SRC) effects and the psychological refractory period (PRP) effect individually and jointly. The empirical findings and theoretical explanations of SRC effects that have been studied within a single-task context suggest that there are two response-selection routes-automatic activation and intentional translation. In contrast, all major PRP models reviewed in this paper have treated response selection as a single processing stage. In particular, the response-selection bottleneck (RSB) model assumes that the processing of Task 1 and Task 2 comprises two separate streams and that the PRP effect is due to a bottleneck located at response selection. Yet, considerable evidence from studies of SRC in the PRP paradigm shows that the processing of the two tasks is more interactive than is suggested by the RSB model and by most other models of the PRP effect. The major implication drawn from the studies of SRC effects in the PRP context is that response activation is a distinct process from final response selection. Response activation is based on both long-term and short-term task-defined S-R associations and occurs automatically and in parallel for the two tasks. The final response selection is an intentional act required even for highly compatible and practiced tasks and is restricted to processing one task at a time. Investigations of SRC effects and response-selection variables in dual-task contexts should be conducted more systematically because they provide significant insight into the nature of response-selection mechanisms.

Transfection in perfused microfluidic cell culture devices: A case study.

PubMed

Raimes, William; Rubi, Mathieu; Super, Alexandre; Marques, Marco P C; Veraitch, Farlan; Szita, Nicolas

2017-08-01

Automated microfluidic devices are a promising route towards a point-of-care autologous cell therapy. The initial steps of induced pluripotent stem cell (iPSC) derivation involve transfection and long term cell culture. Integration of these steps would help reduce the cost and footprint of micro-scale devices with applications in cell reprogramming or gene correction. Current examples of transfection integration focus on maximising efficiency rather than viable long-term culture. Here we look for whole process compatibility by integrating automated transfection with a perfused microfluidic device designed for homogeneous culture conditions. The injection process was characterised using fluorescein to establish a LabVIEW-based routine for user-defined automation. Proof-of-concept is demonstrated by chemically transfecting a GFP plasmid into mouse embryonic stem cells (mESCs). Cells transfected in the device showed an improvement in efficiency (34%, n = 3) compared with standard protocols (17.2%, n = 3). This represents a first step towards microfluidic processing systems for cell reprogramming or gene therapy.

Digital holographic microscopy long-term and real-time monitoring of cell division and changes under simulated zero gravity.

PubMed

Pan, Feng; Liu, Shuo; Wang, Zhe; Shang, Peng; Xiao, Wen

2012-05-07

The long-term and real-time monitoring the cell division and changes of osteoblasts under simulated zero gravity condition were succeed by combing a digital holographic microscopy (DHM) with a superconducting magnet (SM). The SM could generate different magnetic force fields in a cylindrical cavity, where the gravitational force of biological samples could be canceled at a special gravity position by a high magnetic force. Therefore the specimens were levitated and in a simulated zero gravity environment. The DHM was modified to fit with SM by using single mode optical fibers and a vertically-configured jig designed to hold specimens and integrate optical device in the magnet's bore. The results presented the first-phase images of living cells undergoing dynamic divisions and changes under simulated zero gravity environment for a period of 10 hours. The experiments demonstrated that the SM-compatible DHM setup could provide a highly efficient and versatile method for research on the effects of microgravity on biological samples.

Evaluation of new laser spectrometer techniques for in-situ carbon monoxide measurements

NASA Astrophysics Data System (ADS)

Zellweger, C.; Steinbacher, M.; Buchmann, B.

2012-10-01

Long-term time series of the atmospheric composition are essential for environmental research and thus require compatible, multi-decadal monitoring activities. The current data quality objectives of the World Meteorological Organization (WMO) for carbon monoxide (CO) in the atmosphere are very challenging to meet with the measurement techniques that have been used until recently. During the past few years, new spectroscopic techniques came to market with promising properties for trace gas analytics. The current study compares three instruments that have recently become commercially available (since 2011) with the best currently available technique (Vacuum UV Fluorescence) and provides a link to previous comparison studies. The instruments were investigated for their performance regarding repeatability, reproducibility, drift, temperature dependence, water vapour interference and linearity. Finally, all instruments were examined during a short measurement campaign to assess their applicability for long-term field measurements. It could be shown that the new techniques perform considerably better compared to previous techniques, although some issues, such as temperature influence and cross sensitivities, need further attention.

Evaluation of Long-Term Pavement Performance (LTTP) Climatic Data for Use in Mechanistic-Empirical Pavement Design Guide (MEPDG) Calibration and Other Pavement Analysis

DOT National Transportation Integrated Search

2015-05-01

Improvements in the Long-Term Pavement Performance (LTPP) Programs climate data are needed to support current and future research into climate effects on pavement materials, design, and performance. The calibration and enhancement of the Mechanist...

Self-Calibrating, Variable-Flow Pumping System

NASA Technical Reports Server (NTRS)

Walls, Joe T.

1994-01-01

Pumping system provides accurate, controlled flows of two chemical liquids mixed in spray head and react to form rigid or flexible polyurethane or polyisocyanurate foam. Compatible with currently used polyurethane-based coating materials and gas-bubble-forming agents (called "blowing agents" in industry) and expected to be compatible with materials that used in near future. Handles environmentally acceptable substitutes for chlorofluorocarbon foaming agents.

Could We Make Diverse Learning Materials Compatible with E-Readers Used in Classroom Learning Settings?

ERIC Educational Resources Information Center

Young, Shelley Shwu-Ching; Lin, Wei-Lin

2012-01-01

This study explores how to make diverse learning/instructional materials compatible with e-readers when the instructor pioneered to adopt e-readers into a course of the graduate level. What problems did the instructor encounter when she used the e-readers as a major tool to deliver learning contents, such as the process of converting the…

A 1-D evolutionary model for icy satellites, applied to Enceladus

NASA Astrophysics Data System (ADS)

Malamud, Uri; Prialnik, Dina

2016-04-01

We develop a long-term 1-D evolution model for icy satellites that couples multiple processes: water migration and differentiation, geochemical reactions and silicate phase transitions, compaction by self-gravity, and ablation. The model further considers the following energy sources and sinks: tidal heating, radiogenic heating, geochemical energy released by serpentinization or absorbed by mineral dehydration, gravitational energy and insolation, and heat transport by conduction, convection, and advection. We apply the model to Enceladus, by guessing the initial conditions that would render a structure compatible with present-day observations, assuming the initial structure to have been homogeneous. Assuming the satellite has been losing water continually along its evolution, we postulate that it was formed as a more massive, more icy and more porous satellite, and gradually transformed into its present day state due to sustained long-term tidal heating. We consider several initial compositions and evolution scenarios and follow the evolution for the age of the Solar System, testing the present day model results against the available observational constraints. Our model shows the present configuration to be differentiated into a pure icy mantle, several tens of km thick, overlying a rocky core, composed of dehydrated rock at the center and hydrated rock in the outer part. For Enceladus, it predicts a higher rock/ice mass ratio than previously assumed and a thinner ice mantle, compatible with recent estimates based on gravity field measurements. Although, obviously, the model cannot be used to explain local phenomena, it sheds light on the internal structure invoked in explanations of localized features and activities.

Long term thermoelectric module testing system.

PubMed

D'Angelo, Jonathan; Hogan, Timothy

2009-10-01

Thermoelectric generators can be used for converting waste heat into electric power. Significant interest in developing new materials in recent years has led to the discovery of several promising thermoelectrics, however, there can be considerable challenges in developing the materials into working devices. Testing and feedback is needed at each step to gain valuable information for identification of difficulties, quality of the materials and modules, repeatability in fabrication, and longevity of the devices. This paper describes a long-term module testing system for monitoring the output power of a module over extended testing times. To evaluate the system, we have tested commercially available thermoelectric modules over a one month time period.

Interim results of long-term environmental exposures of advanced composites for aircraft applications

NASA Technical Reports Server (NTRS)

Pride, R. A.

1978-01-01

Interim results from a number of ongoing, long-term environmental effects programs for composite materials are reported. The flight service experience is evaluated for 142 composite aircraft components after more than five years and one million successful component flight hours. Ground-based outdoor exposures of composite material coupons after 3 years of exposure at five sites have reached equilibrium levels of moisture pickup which are predictable. Solar ultraviolet-induced material loss is discussed for these same exposures. No significant degradation has been observed in residual strength for either stressed or unstressed specimens, or for exposures to aviation fuels and fluids.

Performance of sulphate- and selenium-reducing biochemical reactors using different ratios of labile to recalcitrant organic materials.

PubMed

Mirjafari, Parissa; Baldwin, Susan A

2015-01-01

Successful operation of sulphate-reducing bioreactors using complex organic materials depends on providing a balance between more easily degrading material that achieves reasonable kinetics and low hydraulic retention times, and more slowly decomposing material that sustains performance in the long term. In this study, two organic mixtures containing the same ingredients typical of bioreactors used at mine sites (woodchips, hay and cow manure) but with different ratios of wood (recalcitrant) to hay (labile) were tested in six continuous flow bioreactors treating synthetic mine-affected water containing 600 mg/L of sulphate and 15 μg/L of selenium. The reactors were operated for short (5-6 months) and long (435-450 days) periods of time at the same hydraulic retention time of 15 days. There were no differences in the performance of the bioreactors in terms of sulphate-reduction over the short term, but the wood-rich bioreactors experienced variable and sometimes unreliable sulphate-reduction over the long term. Presence of more hay in the organic mixture was able to better sustain reliable performance. Production of dissolved organic compounds due to biodegradation within the bioreactors was detected for the first 175-230 days, after which their depletion coincided with a crash phase observed in the wood-rich bioreactors only.

Intermediate Temperature Fluids Life Tests - Experiments

NASA Technical Reports Server (NTRS)

Anderson, William G.; Bonner, Richard W.; Dussinger, Peter M.; Hartenstine, John R.; Sarraf, David B.; Locci, Ivan E.

2007-01-01

There are a number of different applications that could use heat pipes or loop heat pipes (LHPs) in the intermediate temperature range of 450 to 725 K (170 to 450 C), including space nuclear power system radiators, fuel cells, and high temperature electronics cooling. Historically, water has been used in heat pipes at temperatures up to about 425 K (150 C). Recent life tests, updated below, demonstrate that titanium/water and Monel/water heat pipes can be used at temperatures up to 550 K (277 C), due to water's favorable transport properties. At temperatures above roughly 570 K (300 C), water is no longer a suitable fluid, due to high vapor pressure and low surface tension as the critical point is approached. At higher temperatures, another working fluid/envelope combination is required, either an organic or halide working fluid. An electromotive force method was used to predict the compatibility of halide working fluids with envelope materials. This procedure was used to reject aluminum and aluminum alloys as envelope materials, due to their high decomposition potential. Titanium and three corrosion resistant superalloys were chosen as envelope materials. Life tests were conducted with these envelopes and six different working fluids: AlBr3, GaCl3, SnCl4, TiCl4, TiBr4, and eutectic diphenyl/diphenyl oxide (Therminol VP-1/Dowtherm A). All of the life tests except for the GaCl3 are ongoing; the GaCl3 was incompatible. As the temperature approaches 725 K (450 C), cesium is a potential heat pipe working fluid. Life tests results are also presented for cesium/Monel 400 and cesium/70-30 copper/nickel heat pipes operating near 750 K (477 C). These materials are not suitable for long term operation, due to copper transport from the condenser to the evaporator.

Erosion and sediment transport in the Owens River near Bishop, California

USGS Publications Warehouse

Williams, Rhea P.

1975-01-01

Closure of Pleasant Valley Dam in 1954 has almost eliminated the supply of gravel to the 16-mile (25.7-kilometre) study reach of the Owens River. Because of armoring of the channel, scour has been limited to approximately 1 foot (0.3 metre) in the upper 2.3 miles (3.7 kilometres).This report presents information useful in determining long-term erosion effects below Pleasant Valley Dam, in assessing the feasibility of a proposed bypass channel versus retention of the main channel in its present state, and in determining man's influence on river morphology.Bedload transport is dependent on the hydraulics of a section and the availability of material. Ninety-eight percent by weight of the sampled bedload transported between sites 1 and 6 in the study reach was finer than 8 millimetres, although only 6 to 12 percent of the material in the bed available for transport was finer than 8 millimetres. Bank material, a prime source of new material for transport, is predominantly finer than 16 millimetres.Bank erosion is accelerated by wide ranges in flow release. The bank-erosion rates interpreted from aerial photographs indicate average annual erosion rates of 750 tons (680 tonnes) from 1947 to 1967, 1,970 tons (1,790 tonnes) from 1967 to 1968, and 2,020 tons (1,830 tonnes) from 1968 to 1971. These rates are compatible with the water discharge-sediment discharge relation developed from field data collected during 1972-73.Hydraulic geometry of the six sites indicates a shift in the river system regime since 1954. These changes have progressed downstream from the dam to a point between sites 4 and 5. Farther downstream channel changes will occur until the channel stabilizes.

LONG TERM OPERATION ISSUES FOR ELECTRICAL CABLE SYSTEMS IN NUCLEAR POWER PLANTS

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

Fifield, Dr Leonard S; Duckworth, Robert C; Glass III, Dr. Samuel W.

Nuclear power plants contain hundreds of kilometers of electrical cables including cables used for power, for instrumentation, and for control. It is essential that safety-related cable systems continue to perform following a design-basis event. Wholesale replacement of electrical cables in existing plants facing licensing period renewal is both impractical and cost-prohibitive. It is therefore important to understand the long term aging of cable materials to have confidence that aged cables will perform when needed. It is equally important in support of cable aging management to develop methods to evaluate the health of installed cables and inform selective cable replacement decisions.more » The most common insulation materials for electrical cables in nuclear power plants are cross-linked polyethylene and ethylene-propylene rubber. The mechanical properties of these materials degrade over time in the presence of environmental stresses including heat, gamma irradiation, and moisture. Mechanical degradation of cable insulation beyond a certain threshold is unacceptable because it can lead to insulation cracking, exposure of energized conductors, arcing and burning or loss of the ability of the cable system to function during a design-basis accident. While thermal-, radiation-, and moisture-related degradation of polymer insulation materials has been extensively studied over the last few decades, questions remain regarding the long-term performance of cable materials in nuclear plant-specific environments. Identified knowledge gaps include an understanding of the temperature-dependence of activation energies for thermal damage and an understanding of the synergistic effects of radiation and thermal stress on polymer degradation. Many of the outstanding questions in the aging behavior of cable materials relate to the necessity of predicting long-term field degradation using accelerated aging results from the laboratory. Materials degrade faster under more extreme conditions, but extension of behavior to long term degradation under more mild conditions, such as those experienced by most installed cables in nuclear power plants, is complicated by the fact that different degradation mechanisms may be involved in extreme and mild scenarios. The discrepancy in predicted results from short term, more extreme exposure and actual results from longer term, more mild exposures can be counter intuitive. For instance, due to the attenuation of oxidation penetration in material samples rapidly aged through exposure to high temperatures, the bulk of the samples may be artificially protected from thermal aging. In another example, simultaneous exposure of cable insulation material to heat and radiation may actually lead to less damage at higher temperatures than may be observed at lower temperatures. The Light Water Reactor Sustainability program of the United States (US) Department of Energy Office (DOE) of Nuclear Energy is funding research to increase the predictive understanding of electrical cable material aging and degradation in existing nuclear power plants in support of continued safe operation of plants beyond their initial license periods. This research includes the evaluation and development of methods to assess installed cable condition.« less

Pollinator limitation and the effect of breeding systems on plant reproduction in forest fragments

NASA Astrophysics Data System (ADS)

Nayak, K. Geetha; Davidar, Priya

2010-03-01

Reproduction of plants in fragmented habitats may be limited because of lower diversity or abundance of pollinators, and/or variation in local plant density. We assessed natural fruit set and pollinator limitation in ten species of woody plants in natural and restored fragments in the Pondicherry region of southern India, to see whether breeding system of plants (self-compatible and self-incompatible) affected fruit set. We tested whether the number of flowering individuals in the fragments affected the fruit set and further examined the adult and sapling densities of self-compatible (SC) and self-incompatible (SI) species. We measured the natural level of fruit set and pollinator limitation (calculated as the difference in fruit set between hand cross-pollinated and naturally pollinated flowers). Our results demonstrate that there was a higher level of pollinator limitation and hence lower levels of natural fruit set in self-incompatible species as compared to self-compatible species. However, the hand cross-pollinated flowers in SC and SI species produced similar levels of fruit set, further indicating that lower fruit set was due to pollinator limitation and not due to lack of cross-compatible individuals in the fragments. There was no significant relation between number of flowering individuals and the levels of natural fruit set, except for two species Derris ovalifolia, Ixora pavetta. In these species the natural fruit set decreased with increasing population size, again indicating pollinator limitation. The adult and sapling densities in self-compatible species were significantly higher than in self-incompatible species. These findings indicate that the low reproductive output in self-incompatible species may eventually lead to lower population sizes. Restoration of pollinator services along with plant species in fragmented habitats is important for the long-term conservation of biodiversity.

The flanker compatibility effect as a function of visual angle, attentional focus, visual transients, and perceptual load: a search for boundary conditions.

PubMed

Miller, J

1991-03-01

When subjects must respond to a relevant center letter and ignore irrelevant flanking letters, the identities of the flankers produce a response compatibility effect, indicating that they are processed semantically at least to some extent. Because this effect decreases as the separation between target and flankers increases, the effect appears to result from imperfect early selection (attenuation). In the present experiments, several features of the focused attention paradigm were examined, in order to determine whether they might produce the flanker compatibility effect by interfering with the operation of an early selective mechanism. Specifically, the effect might be produced because the paradigm requires subjects to (1) attend exclusively to stimuli within a very small visual angle, (2) maintain a long-term attentional focus on a constant display location, (3) focus attention on an empty display location, (4) exclude onset-transient flankers from semantic processing, or (5) ignore some of the few stimuli in an impoverished visual field. The results indicate that none of these task features is required for semantic processing of unattended stimuli to occur. In fact, visual angle is the only one of the task features that clearly has a strong influence on the size of the flanker compatibility effect. The invariance of the flanker compatibility effect across these conditions suggests that the mechanism for early selection rarely, if ever, completely excludes unattended stimuli from semantic analysis. In addition, it shows that selective mechanisms are relatively insensitive to several factors that might be expected to influence them, thereby supporting the view that spatial separation has a special status for visual selective attention.

Planetary quarantine

NASA Technical Reports Server (NTRS)

1971-01-01

Methods for presterilization cleaning or decontamination of spacecraft hardware to reduce microbial load, without harming materials or spacecraft components, are investigated. Three methods were considered: (1) chemicals in liquid form, relying on physical removal as well as bacterial or bacteriostatic action; (2) chemicals used in the gaseous phase, relying on bacterial activity; and (3) mechanical cleaning relying on physical removal of organisms. These methods were evaluated in terms of their effectiveness in microbial burden reduction and compatibility with spacecraft hardware. Results show chemical methods were effective against spore microorganisms but were harmful to spacecraft materials. Mechanical methods were also effective with the degree depending upon the type of instrument employed. Mechanical methods caused problems in handling the equipment, due to vacuum pressure damaging the very thin layered materials used for shielding, and the bristles used in the process caused streaks or abrasions on some spacecraft components.

Myocardial Adeno-Associated Virus Serotype 6–βARKct Gene Therapy Improves Cardiac Function and Normalizes the Neurohormonal Axis in Chronic Heart Failure

PubMed Central

Rengo, Giuseppe; Lymperopoulos, Anastasios; Zincarelli, Carmela; Donniacuo, Maria; Soltys, Stephen; Rabinowitz, Joseph E.; Koch, Walter J.

2009-01-01

Background The upregulation of G protein–coupled receptor kinase 2 in failing myocardium appears to contribute to dysfunctional β-adrenergic receptor (βAR) signaling and cardiac function. The peptide βARKct, which can inhibit the activation of G protein–coupled receptor kinase 2 and improve βAR signaling, has been shown in transgenic models and short-term gene transfer experiments to rescue heart failure (HF). This study was designed to evaluate long-term βARKct expression in HF with the use of stable myocardial gene delivery with adeno-associated virus serotype 6 (AAV6). Methods and Results In HF rats, we delivered βARKct or green fluorescent protein as a control via AAV6-mediated direct intramyocardial injection. We also treated groups with concurrent administration of the β-blocker metoprolol. We found robust and long-term transgene expression in the left ventricle at least 12 weeks after delivery. βARKct significantly improved cardiac contractility and reversed left ventricular remodeling, which was accompanied by a normalization of the neurohormonal (catecholamines and aldosterone) status of the chronic HF animals, including normalization of cardiac βAR signaling. Addition of metoprolol neither enhanced nor decreased βARKct-mediated beneficial effects, although metoprolol alone, despite not improving contractility, prevented further deterioration of the left ventricle. Conclusions Long-term cardiac AAV6-βARKct gene therapy in HF results in sustained improvement of global cardiac function and reversal of remodeling at least in part as a result of a normalization of the neurohormonal signaling axis. In addition, βARKct alone improves outcomes more than a β-blocker alone, whereas both treatments are compatible. These findings show that βARKct gene therapy can be of long-term therapeutic value in HF. PMID:19103992

Providing Extrinsic Reward for Test Performance Undermines Long-Term Memory Acquisition.

PubMed

Kuhbandner, Christof; Aslan, Alp; Emmerdinger, Kathrin; Murayama, Kou

2016-01-01

Based on numerous studies showing that testing studied material can improve long-term retention more than restudying the same material, it is often suggested that the number of tests in education should be increased to enhance knowledge acquisition. However, testing in real-life educational settings often entails a high degree of extrinsic motivation of learners due to the common practice of placing important consequences on the outcome of a test. Such an effect on the motivation of learners may undermine the beneficial effects of testing on long-term memory because it has been shown that extrinsic motivation can reduce the quality of learning. To examine this issue, participants learned foreign language vocabulary words, followed by an immediate test in which one-third of the words were tested and one-third restudied. To manipulate extrinsic motivation during immediate testing, participants received either monetary reward contingent on test performance or no reward. After 1 week, memory for all words was tested. In the immediate test, reward reduced correct recall and increased commission errors, indicating that reward reduced the number of items that can benefit from successful retrieval. The results in the delayed test revealed that reward additionally reduced the gain received from successful retrieval because memory for initially successfully retrieved words was lower in the reward condition. However, testing was still more effective than restudying under reward conditions because reward undermined long-term memory for concurrently restudied material as well. These findings indicate that providing performance-contingent reward in a test can undermine long-term knowledge acquisition.

Providing Extrinsic Reward for Test Performance Undermines Long-Term Memory Acquisition

PubMed Central

Kuhbandner, Christof; Aslan, Alp; Emmerdinger, Kathrin; Murayama, Kou

2016-01-01

Based on numerous studies showing that testing studied material can improve long-term retention more than restudying the same material, it is often suggested that the number of tests in education should be increased to enhance knowledge acquisition. However, testing in real-life educational settings often entails a high degree of extrinsic motivation of learners due to the common practice of placing important consequences on the outcome of a test. Such an effect on the motivation of learners may undermine the beneficial effects of testing on long-term memory because it has been shown that extrinsic motivation can reduce the quality of learning. To examine this issue, participants learned foreign language vocabulary words, followed by an immediate test in which one-third of the words were tested and one-third restudied. To manipulate extrinsic motivation during immediate testing, participants received either monetary reward contingent on test performance or no reward. After 1 week, memory for all words was tested. In the immediate test, reward reduced correct recall and increased commission errors, indicating that reward reduced the number of items that can benefit from successful retrieval. The results in the delayed test revealed that reward additionally reduced the gain received from successful retrieval because memory for initially successfully retrieved words was lower in the reward condition. However, testing was still more effective than restudying under reward conditions because reward undermined long-term memory for concurrently restudied material as well. These findings indicate that providing performance–contingent reward in a test can undermine long-term knowledge acquisition. PMID:26869978

[The Analysis of Traditional Lime Mortars from Zhejiang Province, China].

PubMed

Liu, Xiao-bin; Cui, Biao; Zhang, Bing-jian

2016-01-01

The components of ancient mortars have always been an important research field in historic building conservation. It has been well known that using traditional mortars in conservation projects have many advantages, such as compatibility and stability. So, developing new binding materials based on traditional mortar has become an international study hotspot. With China's economic development, the protection of ancient buildings also began to put on the agenda, but the understanding on Chinese traditional mortar is limited, and rare literatures are reported. In the present work, the authors investigate seven ancient city wall sites in Zhejiang Province in situ, and subsequently laboratory analysis were carried out on collected mortar samples. The characterizations of mortar samples were made by multi-density gauge, XRD, FTIR, TG-DSC and wet chemical analysis. The experimental results showed that: the main component of masonry mortars is calcium carbonate, the content between 75% - 90%, and they should be made from relatively pure lime mortar. The raw materials of mortar samples were mainly calcareous quick lime, and sample from Taizhou city also contained magnesium quick lime. There are four city walls were built by sticky-rice mortars. It suggests that the technology of adding the sticky rice soup into mortar was universal in the Ming Dynasties. These mortars have lower density between 1.2 and 1.9 g x cm(-3); this outcome should be the result of long-term natural erosion. We have also analyzed other chemical and physical characteristics of these masonry mortars. The results can afford the basic data for the future repairmen programs, development of new protective materials, and comparative study of mortars.

Hyperbaric Oxygen Therapy and Oxygen Compatibility of Skin and Wound Care Products

PubMed Central

Bernatchez, Stéphanie F.; Tucker, Joseph; Chiffoleau, Gwenael

2017-01-01

Objective: Use test methods to assess the oxygen compatibility of various wound care products. Approach: There are currently no standard test methods specifically for evaluating the oxygen compatibility and safety of materials under hyperbaric oxygen (HBO) conditions. However, tests such as the oxygen index (OI), oxygen exposure (OE), and autogenous ignition temperature (AIT) can provide useful information. Results: The OI test measures the minimum oxygen concentration that will support candle-like burning, and it was used to test 44 materials. All but two exhibited an OI equal to or greater (safer) than a control material commonly used in HBO. The OE test exposes each material to an oxygen-enriched atmosphere (>99.5% oxygen) to monitor temperature and pressure for an extended duration. The results of the OE testing indicated that none of the 44 articles tested with this method self-ignited within the 60°C, 3 atm pressurized oxygen atmosphere. The AIT test exposes materials to a rapid ramp up in temperature in HBO conditions at 3 atm until ignition occurs. Ten wound care materials and seven materials usually avoided in HBO chambers were tested. The AIT ranged from 138°C to 384°C for wound care products and from 146°C to 420°C for the other materials. Innovation: This work provides useful data and recommendations to help develop a new standard approach for evaluating the HBO compatibility of wound care products to ensure safety for patients and clinicians. Conclusion: The development of an additional test to measure the risk of electrostatic discharge of materials in HBO conditions is needed. PMID:29098113

47 CFR 20.19 - Hearing aid-compatible mobile handsets.

Code of Federal Regulations, 2014 CFR

2014-10-01

... required to include this language in the packaging material for handsets that incorporate a Wi-Fi air... aid compatibility with respect to Wi-Fi operation. (iii) Each manufacturer and service provider shall...

47 CFR 20.19 - Hearing aid-compatible mobile handsets.

Code of Federal Regulations, 2013 CFR

2013-10-01

... required to include this language in the packaging material for handsets that incorporate a Wi-Fi air... aid compatibility with respect to Wi-Fi operation. (iii) Each manufacturer and service provider shall...

47 CFR 20.19 - Hearing aid-compatible mobile handsets.

Code of Federal Regulations, 2012 CFR

2012-10-01

... required to include this language in the packaging material for handsets that incorporate a Wi-Fi air... aid compatibility with respect to Wi-Fi operation. (iii) Each manufacturer and service provider shall...

Enhanced Therapeutic and Long-Term Dynamic Vascularization Effects of Human Pluripotent Stem Cell-Derived Endothelial Cells Encapsulated in a Nanomatrix Gel.

PubMed

Lee, Shin-Jeong; Sohn, Young-Doug; Andukuri, Adinarayana; Kim, Sangsung; Byun, Jaemin; Han, Ji Woong; Park, In-Hyun; Jun, Ho-Wook; Yoon, Young-Sup

2017-11-14

Human pluripotent stem cell (hPSC)-derived endothelial cells (ECs) have limited clinical utility because of undefined components in the differentiation system and poor cell survival in vivo. Here, we aimed to develop a fully defined and clinically compatible system to differentiate hPSCs into ECs. Furthermore, we aimed to enhance cell survival, vessel formation, and therapeutic potential by encapsulating hPSC-ECs with a peptide amphiphile (PA) nanomatrix gel. We induced differentiation of hPSCs into the mesodermal lineage by culturing on collagen-coated plates with a glycogen synthase kinase 3β inhibitor. Next, vascular endothelial growth factor, endothelial growth factor, and basic fibroblast growth factor were added for endothelial lineage differentiation, followed by sorting for CDH5 (VE-cadherin). We constructed an extracellular matrix-mimicking PA nanomatrix gel (PA-RGDS) by incorporating the cell adhesive ligand Arg-Gly-Asp-Ser (RGDS) and a matrix metalloproteinase-2-degradable sequence. We then evaluated whether the encapsulation of hPSC-CDH5 + cells in PA-RGDS could enhance long-term cell survival and vascular regenerative effects in a hind-limb ischemia model with laser Doppler perfusion imaging, bioluminescence imaging, real-time reverse transcription-polymerase chain reaction, and histological analysis. The resultant hPSC-derived CDH5 + cells (hPSC-ECs) showed highly enriched and genuine EC characteristics and proangiogenic activities. When injected into ischemic hind limbs, hPSC-ECs showed better perfusion recovery and higher vessel-forming capacity compared with media-, PA-RGDS-, or human umbilical vein EC-injected groups. However, the group receiving the PA-RGDS-encapsulated hPSC-ECs showed better perfusion recovery, more robust and longer cell survival (> 10 months), and higher and prolonged angiogenic and vascular incorporation capabilities than the bare hPSC-EC-injected group. Surprisingly, the engrafted hPSC-ECs demonstrated previously unknown sustained and dynamic vessel-forming behavior: initial perivascular concentration, a guiding role for new vessel formation, and progressive incorporation into the vessels over 10 months. We generated highly enriched hPSC-ECs via a clinically compatible system. Furthermore, this study demonstrated that a biocompatible PA-RGDS nanomatrix gel substantially improved long-term survival of hPSC-ECs in an ischemic environment and improved neovascularization effects of hPSC-ECs via prolonged and unique angiogenic and vessel-forming properties. This PA-RGDS-mediated transplantation of hPSC-ECs can serve as a novel platform for cell-based therapy and investigation of long-term behavior of hPSC-ECs. © 2017 American Heart Association, Inc.

Development of Design Standards and Guidelines for Electromagnetic Compatibility and Lightning Protection for Spacecraft Utilizing Composite Materials

NASA Technical Reports Server (NTRS)

1996-01-01

Preliminary design guidelines necessary to assure electromagnetic compatibility (EMC) of spacecraft using composite materials, are presented. A database of electrical properties of composite materials which may have an effect on EMC is established. The guidelines concentrate on the composites that are conductive but may require enhancement to be adequate for EMC purposes. These composites are represented by graphite reinforced polymers. Methods for determining adequate conductivity levels for various EMC purposes are defined, along with the methods of design which increase conductivity of composite materials and joints to adequate levels.

Oxygen fires, materials compatibility and system contaminants

NASA Astrophysics Data System (ADS)

Barter, Simon A.; Hillen, Lance W.

An evaluation is made of aircraft fires initiated by oxygen systems, giving attention to such systems' mechanical design and materials-selection factors. While many oxygen compatibility tests are conducted on single components, operational systems become contaminated through frequent use and occasional abuse; it is therefore essential for the designer to have information about the oxygen compatibility of the entire spectrum of potential contaminants and their various combinations. Valve designs are noted to be especially sensitive to system contamination. Gaseous oxygen fire severity is fundamentally determined by the period of oxygen flow. There is a clear need for an automatic shut-off device which would operate when abnormal flow conditions occur.

The impact of subliminal effect images in voluntary vs. stimulus-driven actions.

PubMed

Le Bars, Solène; Hsu, Yi-Fang; Waszak, Florian

2016-11-01

According to the ideomotor theory, actions are represented in terms of their sensory effects. In the current study we tested whether subliminal effect images influence action control (1) at early and/or late preparatory stages of (2) voluntary actions or stimulus-driven actions (3) with or without Stimulus-Response (S-R) compatibility. In Experiment 1, participants were presented at random with 50% of S-R compatible stimulus-driven action trials and 50% of voluntary action trials. The actions' effects (i.e. up- or down-pointing arrows) were presented subliminally before each action (i.e. a keypress). In voluntary actions, participants selected more often the action congruent with the prime when it was presented at long intervals before the action. Moreover they responded faster in prime-congruent than in prime-incongruent trials when primes were presented at short intervals before the action. In Experiment 2, participants were only presented with stimulus-driven action trials, with or without S-R compatibility. In stimulus-driven action trials with S-R compatibility (e.g., left-pointing arrow signaling a left keypress), subliminal action-effects did not generate any significant effect on RTs or error rates. On the other hand, in stimulus-driven action trials without S-R compatibility (e.g., letter "H" signaling a left keypress), participants were significantly faster in prime-congruent trials when primes were presented at the shortest time interval before the action. These results suggest that subliminal effect images facilitate voluntary action preparation on an early and a late level. Stimulus-driven action preparation is influenced on a late level only, and only if there is no compatibility between the stimulus and the motor response, that is when the response is not automatically triggered by the common properties existing between the stimulus and the required action. Copyright © 2016 Elsevier B.V. All rights reserved.

Similar local order in disordered fluorite and aperiodic pyrochlore structures

DOE PAGES

Shamblin, Jacob; Tracy, Cameron; Palomares, Raul; ...

2017-10-01

A major challenge to understanding the response of materials to extreme environments (e.g., nuclear fuels/waste forms and fusion materials) is to unravel the processes by which a material can incorporate atomic-scale disorder, and at the same time, remain crystalline. While it has long been known that all condensed matter, even liquids and glasses, possess short-range order, the relation between fully-ordered, disordered, and aperiodic structures over multiple length scales is not well understood. For example, when defects are introduced (via pressure or irradiation) into materials adopting the pyrochlore structure, these complex oxides either disorder over specific crystallographic sites, remaining crystalline, ormore » become aperiodic. Here we present neutron total scattering results characterizing the irradiation response of two pyrochlores, one that is known to disorder (Er2Sn2O7) and the other to amorphize (Dy2Sn2O7) under ion irradiation. The results demonstrate that in both cases, the local pyrochlore structure is transformed into similar short range configurations that are best fit by the orthorhombic weberite structure, even though the two compositions have distinctly different structures, aperiodic vs. disordered-crystalline, at longer length scales. Thus, a material's resistance to amorphization may not depend primarily on local defect formation energies, but rather on the structure's compatibility with meso-scale modulations of the local order in a way that maintains long-range periodicity.« less

Release Properties and Electrochemical Characterization of Encapsulated Corrosion Inhibitors for Environmentally Friendly Smart Coatings

NASA Technical Reports Server (NTRS)

Pearman, B. P.; Calle, L. M.; Zhang, X.; Li, W.; Buhrow, J. W.; Johnsey, M. N.; Montgomery, E. L.; Fitzpatrick, L.; Surma, J. M.

2015-01-01

The NASA Kennedy Space Center's Corrosion Technology Lab at the Kennedy Space Center in Florida, U.S.A. has been developing multifunctional smart coatings based on the microencapsulation of environmentally friendly corrosion indicators, inhibitors and self-healing agents. This allows for the incorporation of autonomous corrosion control functionalities, such as corrosion detection and inhibition as well as the self-healing of mechanical damage, into coatings. This paper presents technical details on the characterization of inhibitor-containing particles and their corrosion inhibitive effects using electrochemical and mass loss methods. Three organic environmentally friendly corrosion inhibitors were encapsulated in organic microparticles that are compatible with desired coatings. The total inhibitor content and the release of one of the inhibitors from the microparticles in basic solution was measured. Particles with inhibitor contents of up 60 wt% were synthesized. Fast release, for immediate corrosion protection, as well as long-term release for continued protection, was observed. The inhibition efficacy of the inhibitors, both as the pure materials and in microparticles, on carbon steel was evaluated. Polarization curves and mass loss measurements showed that, in the case of 2MBT, its corrosion inhibition effectiveness was greater when it was delivered from microparticles.

The Electromagnetic Compatibility (EMC) Design Challenge for Scientific Spacecraft Powered by a Stirling Power Converter

NASA Technical Reports Server (NTRS)

Sargent, Noel B.

2001-01-01

A 55 We free-piston Stirling Technology Demonstration Convertor (TDC) has been tested as part of an evaluation to determine its feasibility as a means for significantly reducing the amount of radioactive material required compared to Radioisotope Thermoelectric Generators (RTGs) to support long-term space science missions. Measurements were made to quantify the low frequency magnetic and electric fields radiated from the Stirling's 80 Hertz (Hz) linear alternator and control electronics in order to determine the magnitude of reduction that will be required to protect sensitive field sensors aboard some science missions. One identified "Solar Probe" mission requires a 100 dB reduction in the low frequency magnetic field over typical military standard design limits, to protect its plasma wave sensor. This paper discusses the electromagnetic interference (EMI) control options relative to the physical design impacts for this power system, composed of 3 basic electrical elements. They are (1) the Stirling Power Convertor with its linear alternator, (2) the power switching and control electronics to convert the 90 V, 80 Hz alternator output to DC for the use of the spacecraft, and (3) the interconnecting wiring including any instrumentation to monitor and control items 1 and 2.

Cation-Deficient Spinel ZnMn2O4 Cathode in Zn(CF3SO3)2 Electrolyte for Rechargeable Aqueous Zn-Ion Battery.

PubMed

Zhang, Ning; Cheng, Fangyi; Liu, Yongchang; Zhao, Qing; Lei, Kaixiang; Chen, Chengcheng; Liu, Xiaosong; Chen, Jun

2016-10-05

Rechargeable aqueous Zn-ion batteries are attractive cheap, safe and green energy storage technologies but are bottlenecked by limitation in high-capacity cathode and compatible electrolyte to achieve satisfactory cyclability. Here we report the application of nonstoichiometric ZnMn 2 O 4 /carbon composite as a new Zn-insertion cathode material in aqueous Zn(CF 3 SO 3 ) 2 electrolyte. In 3 M Zn(CF 3 SO 3 ) 2 solution that enables ∼100% Zn plating/stripping efficiency with long-term stability and suppresses Mn dissolution, the spinel/carbon hybrid exhibits a reversible capacity of 150 mAh g -1 and a capacity retention of 94% over 500 cycles at a high rate of 500 mA g -1 . The remarkable electrode performance results from the facile charge transfer and Zn insertion in the structurally robust spinel featuring small particle size and abundant cation vacancies, as evidenced by combined electrochemical measurements, XRD, Raman, synchrotron X-ray absorption spectroscopy, FTIR, and NMR analysis. The results would enlighten and promote the use of cation-defective spinel compounds and trifluoromethanesulfonic electrolyte to develop high-performance rechargeable zinc batteries.

Long-term efficacy of wood dip-treated with multicomponent biocides

Treesearch

Carol A. Clausen; Vina W. Yang

2005-01-01

Biocides designed for prevention of indoor mold growth on wood-based materials need to provide long-term protection under conditions of high humidity. Specimens of kiln-dried southern pine and unseasoned southern pine, aspen, and Douglas-fir were dip-treated with borate-dimethylcocoamine (DMCA) supplemented with voriconazole, thiabendazole, or thujaplicin and evaluated...

Short- and Long-Term Effects of Cumulative Finals on Student Learning

ERIC Educational Resources Information Center

Khanna, Maya M.; Brack, Amy S. Badura; Finken, Laura L.

2013-01-01

In two experiments, we examined the benefits of cumulative and noncumulative finals on students' short- and long-term course material retention. In Experiment 1, we examined results from course content exams administered immediately after course finals. Course sections including cumulative finals had higher content exam scores than sections…

Long-Term Outcome of Social Skills Intervention Based on Interactive LEGO[C] Play

ERIC Educational Resources Information Center

Legoff, Daniel B.; Sherman, Michael

2006-01-01

LEGO[C] building materials have been adapted as a therapeutic modality for increasing motivation to participate in social skills intervention, and providing a medium through which children with social and communication handicaps can effectively interact. A 3 year retrospective study of long-term outcome for autistic spectrum children participating…

A Survey of Current Literature on Sampling, Sample Handling, and Long Term Storage for Environmental Materials.

ERIC Educational Resources Information Center

Maienthal, E. J.; Becker, D. A.

This report presents the results of an extensive literature survey undertaken to establish optimum sampling, sample handling and long-term storage techniques for a wide variety of environmental samples to retain sample integrity. The components of interest are trace elements, organics, pesticides, radionuclides and microbiologicals. A bibliography…

Automatic and Controlled Processing in Sentence Recall: The Role of Long-Term and Working Memory

ERIC Educational Resources Information Center

Jefferies, E.; Lambon Ralph, M.A.; Baddeley, A.D.

2004-01-01

Immediate serial recall is better for sentences than word lists presumably because of the additional support that meaningful material receives from long-term memory. This may occur automatically, without the involvement of attention, or may require additional attentionally demanding processing. For example, the episodic buffer model (Baddeley,…

Instructor Guides for Training Food Service Supervisors in Long Term Care Facilities.

ERIC Educational Resources Information Center

Eastern Iowa Community Coll. District, Davenport.

This final report describes a project to develop postsecondary teacher resource guides for supervisor courses in food service management, preparation and service of modified diets, and meal service in long-term care facilities in Iowa. Introductory material includes the following: project objective, a description of how the objective was met, the…

In vitro effect of a corrosive hostile ocular surface on candidate biomaterials for keratoprosthesis skirt

PubMed Central

Tan, Xiao Wei; Riau, Andri; Shi, Zhi Long; Tan, Anna C S; Neoh, Koon Gee; Khor, Khiam Aik; Beuerman, Roger W; Tan, Donald; Mehta, Jodhbir S

2012-01-01

Aim Keratoprosthesis (KPro) devices are prone to long-term corrosion and microbiological assault. The authors aimed to compare the inflammatory response and material dissolution properties of two candidate KPro skirt materials, hydroxyapatite (HA) and titania (TiO2) in a simulated in vitro cornea inflammation environment. Methods Lipopolysaccharide-stimulated cytokine secretions were evaluated with human corneal fibroblasts on both HA and TiO2. Material specimens were subjected to electrochemical and long-term incubation test with artificial tear fluid (ATF) of various acidities. Topography and surface roughness of material discs were analysed by scanning electron microscopy and atomic force microscopy. Results There were less cytokines secreted from human corneal fibroblasts seeded on TiO2 substrates as compared with HA. TiO2 was more resistant to the corrosion effect caused by acidic ATF in contrast to HA. Moreover, the elemental composition of TiO2 was more stable than HA after long-term incubation with ATF. Conclusions TiO2 is more resistant to inflammatory degradation and has a higher corrosion resistance as compared with HA, and in this regard may be a suitable material to replace HA as an osteo-odonto-keratoprosthesis skirt. This would reduce resorption rates for KPro surgery. PMID:22802307

Modeling Long-term Creep Performance for Welded Nickel-base Superalloy Structures for Power Generation Systems

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

Shen, Chen; Gupta, Vipul; Huang, Shenyan

The goal of this project is to model long-term creep performance for nickel-base superalloy weldments in high temperature power generation systems. The project uses physics-based modeling methodologies and algorithms for predicting alloy properties in heterogeneous material structures. The modeling methodology will be demonstrated on a gas turbine combustor liner weldment of Haynes 282 precipitate-strengthened nickel-base superalloy. The major developments are: (1) microstructure-property relationships under creep conditions and microstructure characterization (2) modeling inhomogeneous microstructure in superalloy weld (3) modeling mesoscale plastic deformation in superalloy weld and (4) a constitutive creep model that accounts for weld and base metal microstructure and theirmore » long term evolution. The developed modeling technology is aimed to provide a more efficient and accurate assessment of a material’s long-term performance compared with current testing and extrapolation methods. This modeling technology will also accelerate development and qualification of new materials in advanced power generation systems. This document is a final technical report for the project, covering efforts conducted from October 2014 to December 2016.« less

Density and composition of microorganisms during long-term (418 day) growth of potato using biologically reclaimed nutrients from inedible plant biomass

NASA Technical Reports Server (NTRS)

Garland, J. L.; Cook, K. L.; Johnson, M.; Sumner, R.; Fields, N.; Sager, J. C. (Principal Investigator)

1997-01-01

A study evaluating alternative methods for long term operation of biomass production systems was recently completed at the Kennedy Space Center (KSC). The 418-day study evaluated repeated batch versus mixed-aged production of potato grown on either standard 1/2-strength Hoagland's nutrient solution or solutions including nutrients recycled from inedible plant material. The long term effects of closure and recycling on microbial dynamics were evaluated by monitoring the microbial communities associated with various habitats within the plant growth system (i.e., plant roots, nutrient solution, biofilms within the hydroponic systems, atmosphere, and atmospheric condensate). Plate count methods were used to enumerate and characterize microorganisms. Microscopic staining methods were used to estunate total cell densities. The primary finding was that the density and composition of microbial communities associated with controlled environmental plant growth systems are stable during long term operation. Continuous production resulted in slightly greater stability. Nutrient recycling, despite the addition of soluble organic material from the waste processing system, did not significantly increase microbial density in any of the habitats.

Density and composition of microorganisms during long-term (418 day) growth of potato using biologically reclaimed nutrients from inedible plant biomass

NASA Astrophysics Data System (ADS)

Garland, J. L.; Cook, K. L.; Johnson, M.; Sumner, R.; Fields, N.

1997-01-01

A study evaluating alternative methods for long term operation of biomass production systems was recently completed at the Kennedy Space Center (KSC). The 418-day study evaluated repeated batch versus mixed-aged production of potato grown on either standard 1/2-strength Hoagland's nutrient solution or solutions including nutrients recycled from inedible plant material. The long term effects of closure and recycling on microbial dynamics were evaluated by monitoring the microbial communities associated with various habitats within the plant growth system (i.e., plant roots, nutrient solution, biofilms within the hydroponic systems, atmosphere, and atmospheric condensate). Plate count methods were used to enumerate and characterize microorganisms. Microscopic staining methods were used to estimate total cell densities. The primary finding was that the density and composition of microbial communities associated with controlled environmental plant growth systems are stable during long term operation. Continuous production resulted in slightly greater stability. Nutrient recycling, despite the addition of soluble organic material from the waste processing system, did not significantly increase microbial density in any of the habitats.

Density and composition of microorganisms during long-term (418 day) growth of potato using biologically reclaimed nutrients from inedible plant biomass

NASA Astrophysics Data System (ADS)

1997-01-01

A study evaluating alternative methods for long term operation of biomass production systems was recently completed at the Kennedy Space Center (KSC). The 418-day study evaluated repeated batch versus mixed-aged production of potato grown on either standard 12-strength Hoagland's nutrient solution or solutions including nutrients recycled from inedible plant material. The long term effects of closure and recycling on microbial dynamics were evaluated by monitoring the microbial communities associated with various habitats within the plant growth system (i.e., plant roots, nutrient solution, biofilms within the hydroponic systems, atmosphere, and atmospheric condensate). Plate count methods were used to enumerate and characterize microorganisms. Microscopic staining methods were used to estimate total cell densities. The primary finding was that the density and composition of microbial communities associated with controlled environmental plant growth systems are stable during long term operation. Continuous production resulted in slightly greater stability. Nutrient recycling, despite the addition of soluble organic material from the waste processing system, did not significantly increase microbial density in any of the habitats.

Investigation of Pb Li compatibility issues for the dual coolant blanket concept

NASA Astrophysics Data System (ADS)

Pint, B. A.; Moser, J. L.; Tortorelli, P. F.

2007-08-01

One proposed blanket concept uses advanced ferritic alloys and a SiC/SiC composite flow channel insert with both Pb-17 at.%Li and He coolants. As the first step in determining the long-term compatibility of SiC/SiC in Pb-Li, specimens of high-purity, chemical vapor deposited (CVD) SiC were exposed in capsules for up to 5000 h at 800 °C and 1000 h at 1200 °C. Dissolved Si was detected in the Pb-Li after the highest temperature exposures suggesting that SiC may be limited to <1100 °C in Pb-Li. Aluminide coatings are being considered for corrosion resistant coatings for the tubing between the first wall and the heat exchanger. Initial results indicate that, in Pb-Li at 700 °C, FeCrAl, Fe 3Al and NiAl form a protective alumina layer which reduces dissolution compared to type 316 stainless steel.

Emerging technologies for long-term antimicrobial device coatings: advantages and limitations

PubMed Central

Cyphert, Erika L

2017-01-01

Over the past 20 years, the field of antimicrobial medical device coatings has expanded nearly 30-fold with technologies shifting their focus from diffusion-only based (short-term antimicrobial eluting) coatings to long-term antimicrobial eluting and intrinsically antimicrobial functioning materials. A variety of emergent coatings have been developed with the goal of achieving long-term antimicrobial activity in order to mitigate the risk of implanted device failure. Specifically, the coatings can be grouped into two categories: those that use antibiotics in conjunction with a polymer coating and those that rely on the intrinsic properties of the material to kill or repel bacteria that come into contact with the surface. This review covers both long-term drug-eluting and non-eluting coatings and evaluates the inherent advantages and disadvantages of each type while providing an overview of variety applications that the coatings have been utilized in. Impact statement This work provides an overview, with advantages and limitations of the most recently developed antibacterial coating technologies, enabling other researchers in the field to more easily determine which technology is most advantageous for them to further develop and pursue. PMID:28110543

[Establishment of immortal lymphoblastoid cell bank of keloids pedigree].

PubMed

Song, Mei; Gao, Jian-hua; Yan, Xin; Liu, Xiao-jun; Chen, Yang

2006-11-01

To provide perpetual research materials for long term studies by establishing immortal lymphoblastoid cell bank of keloids pedigree. The immortal lymphoblastoid cell lines of keloids pedigree were established by Epstein-Barr virus transformation of peripheral blood B lymphocytes. 27 immortal lymphoblastoid cell lines of keloids pedigree were obtained successfully, all of the immortal lymphoblastoid cell lines were successfully revivificated after been frozen in liquid nitrogen. It is important to establish immortal lymphoblastoid cell bank of keloids pedigree and provide long-term DNA materials for deep study of keloids in the future.

CMOS compatible electrode materials selection in oxide-based memory devices

NASA Astrophysics Data System (ADS)

Zhuo, V. Y.-Q.; Li, M.; Guo, Y.; Wang, W.; Yang, Y.; Jiang, Y.; Robertson, J.

2016-07-01

Electrode materials selection guidelines for oxide-based memory devices are constructed from the combined knowledge of observed device operation characteristics, ab-initio calculations, and nano-material characterization. It is demonstrated that changing the top electrode material from Ge to Cr to Ta in the Ta2O5-based memory devices resulted in a reduction of the operation voltages and current. Energy Dispersed X-ray (EDX) Spectrometer analysis clearly shows that the different top electrode materials scavenge oxygen ions from the Ta2O5 memory layer at various degrees, leading to different oxygen vacancy concentrations within the Ta2O5, thus the observed trends in the device performance. Replacing the Pt bottom electrode material with CMOS compatible materials (Ru and Ir) further reduces the power consumption and can be attributed to the modification of the Schottky barrier height and oxygen vacancy concentration at the electrode/oxide interface. Both trends in the device performance and EDX results are corroborated by the ab-initio calculations which reveal that the electrode material tunes the oxygen vacancy concentration via the oxygen chemical potential and defect formation energy. This experimental-theoretical approach strongly suggests that the proper selection of CMOS compatible electrode materials will create the critical oxygen vacancy concentration to attain low power memory performance.

Material Science in Cervical Total Disc Replacement.

PubMed

Pham, Martin H; Mehta, Vivek A; Tuchman, Alexander; Hsieh, Patrick C

2015-01-01

Current cervical total disc replacement (TDR) designs incorporate a variety of different biomaterials including polyethylene, stainless steel, titanium (Ti), and cobalt-chrome (CoCr). These materials are most important in their utilization as bearing surfaces which allow for articular motion at the disc space. Long-term biological effects of implanted materials include wear debris, host inflammatory immune reactions, and osteolysis resulting in implant failure. We review here the most common materials used in cervical TDR prosthetic devices, examine their bearing surfaces, describe the construction of the seven current cervical TDR devices that are approved for use in the United States, and discuss known adverse biological effects associated with long-term implantation of these materials. It is important to appreciate and understand the variety of biomaterials available in the design and construction of these prosthetics and the considerations which guide their implementation.

Material Science in Cervical Total Disc Replacement

PubMed Central

Pham, Martin H.; Mehta, Vivek A.; Tuchman, Alexander; Hsieh, Patrick C.

2015-01-01

Current cervical total disc replacement (TDR) designs incorporate a variety of different biomaterials including polyethylene, stainless steel, titanium (Ti), and cobalt-chrome (CoCr). These materials are most important in their utilization as bearing surfaces which allow for articular motion at the disc space. Long-term biological effects of implanted materials include wear debris, host inflammatory immune reactions, and osteolysis resulting in implant failure. We review here the most common materials used in cervical TDR prosthetic devices, examine their bearing surfaces, describe the construction of the seven current cervical TDR devices that are approved for use in the United States, and discuss known adverse biological effects associated with long-term implantation of these materials. It is important to appreciate and understand the variety of biomaterials available in the design and construction of these prosthetics and the considerations which guide their implementation. PMID:26523281

Unique research challenges for high-speed civil transports

NASA Technical Reports Server (NTRS)

Jackson, Charlie M., Jr.; Morris, E. K., Jr.

1988-01-01

Market growth and technological advances are expected to lead to a generation of long-range transports that cruise at supersonic or even hypersonic speeds. Current NASA/industry studies will define the market windows in terms of time frame, Mach number, and technology requirements for these aircraft. Initial results indicate that, for the years 2000 to 2020, economically attractive vehicles could have a cruise speed up to Mach 6. The resulting research challenges are unique. They must be met with technologies that will produce commercially successful and environmentally compatible vehicles where none have existed. Several important areas of research were identified for the high-speed civil transports. Among these are sonic boom, takeoff noise, thermal management, lightweight structures with long life, unique propulsion concepts, unconventional fuels, and supersonic laminar flow.

Unique research challenges for high-speed civil transports

NASA Technical Reports Server (NTRS)

Jackson, Charlie M., Jr.; Morris, Charles E. K., Jr.

1987-01-01

Market growth and technological advances are expected to lead to a generation of long-range transports that cruise at supersonic or even hypersonic speeds. Current NASA/industry studies will define the market windows in terms of time frame, Mach number, and technology requirements for these aircraft. Initial results indicate that, for the years 2000 to 2020, economically attractive vehicles could have a cruise speed up to Mach 6. The resulting research challenges are unique. They must be met with technologies that will produce commercially successful and environmentally compatible vehicles where none have existed. Several important areas of research were identified for the high-speed civil transports. Among these are sonic boom, takeoff noise, thermal management, lightweight structures with long life, unique propulsion concepts, unconventional fuels, and supersonic laminar flow.

Electromagnetic Compatibility Design of the Computer Circuits

NASA Astrophysics Data System (ADS)

Zitai, Hong

2018-02-01

Computers and the Internet have gradually penetrated into every aspect of people’s daily work. But with the improvement of electronic equipment as well as electrical system, the electromagnetic environment becomes much more complex. Electromagnetic interference has become an important factor to hinder the normal operation of electronic equipment. In order to analyse the computer circuit compatible with the electromagnetic compatibility, this paper starts from the computer electromagnetic and the conception of electromagnetic compatibility. And then, through the analysis of the main circuit and system of computer electromagnetic compatibility problems, we can design the computer circuits in term of electromagnetic compatibility. Finally, the basic contents and methods of EMC test are expounded in order to ensure the electromagnetic compatibility of equipment.

Design and Fabrication of an MRI-Compatible, Autonomous Incubation System.

PubMed

Khalilzad-Sharghi, Vahid; Xu, Huihui

2015-10-01

Tissue engineers have long sought access to an autonomous, imaging-compatible tissue incubation system that, with minimum operator handling, can provide real-time visualization and quantification of cells, tissue constructs, and organs. This type of screening system, capable of operating noninvasively to validate tissue, can overcome current limitations like temperature shock, unsustainable cellular environments, sample contamination, and handling/stress. However, this type of system has been a major challenge, until now. Here, we describe the design, fabrication, and characterization of an innovative, autonomous incubation system that is compatible with a 9.4 T magnetic resonance imaging (MRI) scanner. Termed the e-incubator (patent pending; application number: 13/953,984), this microcontroller-based system is integrated into an MRI scanner and noninvasively screens cells and tissue cultures in an environment where temperature, pH, and media/gas handling are regulated. The 4-week study discussed herein details the continuous operation of the e-incubator for a tissue-engineered osteogenic construct, validated by LIVE/DEAD(®) cell assays and histology. The evolving MR quantitative parameters of the osteogenic construct were used as biomarkers for bone tissue engineering and to further validate the quality of the product noninvasively before harvesting. Importantly, the e-incubator reliably facilitates culturing cells and tissue constructs to create engineered tissues and/or investigate disease therapies.

Use of Tween Polymer To Enhance the Compatibility of the Li/Electrolyte Interface for the High-Performance and High-Safety Quasi-Solid-State Lithium-Sulfur Battery.

PubMed

Liu, Jie; Qian, Tao; Wang, Mengfan; Zhou, Jinqiu; Xu, Na; Yan, Chenglin

2018-06-07

Lithium metal batteries have attracted increasing attention recently due to their particular advantages in energy density. However, as for their practical application, the development of solid-state lithium metal batteries is restricted because of the poor Li/electrolyte interface, low Li-ion conductivity, and irregular growth of Li dendrites. To address the above issues, we herein report a high Li-ion conductivity and compatible polymeric interfacial layer by grafting tween-20 on active lithium metal. Sequential oxyethylene groups in tween-grafted Li (TG-Li) improve the ion conductivity and the compatibility of the Li/electrolyte interface, which enables low overpotentials and stable performance over 1000 cycles. Consequently, the poly(ethylene oxide)-based solid-state lithium-sulfur battery with TG-Li exhibits a high reversible capacity of 1051.2 mA h g -1 at 0.2 C (1 C = 1675 mA h g -1 ) and excellent stability for 500 cycles at 2 C. The decreasing concentration of the sulfur atom with increasing Ar + sputtering depth indicates that the polymer interfacial layer works well in suppressing polysulfide reduction to Li 2 S/Li 2 S 2 on the metallic Li surface even after long-term cycling.

Creep rupture testing of carbon fiber-reinforced epoxy composites

NASA Astrophysics Data System (ADS)

Burton, Kathryn Anne

Carbon fiber is becoming more prevalent in everyday life. As such, it is necessary to have a thorough understanding of, not solely general mechanical properties, but of long-term material behavior. Creep rupture testing of carbon fiber is very difficult due to high strength and low strain to rupture properties. Past efforts have included testing upon strands, single tows and overwrapped pressure vessels. In this study, 1 inch wide, [0°/90°]s laminated composite specimens were constructed from fabric supplied by T.D. Williamson Inc. Specimen fabrication methods and gripping techniques were investigated and a method was developed to collect long term creep rupture behavior data. An Instron 1321 servo-hydraulic material testing machine was used to execute static strength and short term creep rupture tests. A hanging dead-weight apparatus was designed to perform long-term creep rupture testing. The testing apparatus, specimens, and specimen grips functioned well. Collected data exhibited a power law distribution and therefore, a linear trend upon a log strength-log time plot. Statistical analysis indicated the material exhibited slow degradation behavior, similar to previous studies, and could maintain a 50 year carrying capacity at 62% of static strength, approximately 45.7 ksi.

Information processing. [in human performance

NASA Technical Reports Server (NTRS)

Wickens, Christopher D.; Flach, John M.

1988-01-01

Theoretical models of sensory-information processing by the human brain are reviewed from a human-factors perspective, with a focus on their implications for aircraft and avionics design. The topics addressed include perception (signal detection and selection), linguistic factors in perception (context provision, logical reversals, absence of cues, and order reversals), mental models, and working and long-term memory. Particular attention is given to decision-making problems such as situation assessment, decision formulation, decision quality, selection of action, the speed-accuracy tradeoff, stimulus-response compatibility, stimulus sequencing, dual-task performance, task difficulty and structure, and factors affecting multiple task performance (processing modalities, codes, and stages).

Implementation of the VGM Graphics System on the PDP-11/50 under the RSX-11M Operating System and Construction of a Compatible Software Driver for the Ramtek RM-9400.

DTIC Science & Technology

1982-06-01

no other. is the field of computer grapnIcs expanded, such limitations became a real liability. The inability to use one program at more tnan one...terms of these environmental factors. For example, some programs may be portable from one device to another as long as the computing environment is not...PemPOMMIN OROANI&ATIO NAMI AND A00RESS IQ. PROGRAM CLEMENT. PROJECT. TASK AREA a WORK UNiT muN9ERS Naval Postgraduate School Monterey, California 93940

Gene therapy for eye as regenerative medicine? Lessons from RPE65 gene therapy for Leber's Congenital Amaurosis.

PubMed

Rakoczy, Elizabeth P; Narfström, Kristina

2014-11-01

Recombinant virus mediated gene therapy of Leber's Congenital Amaurosis has provided a wide range of data on the utility of gene replacement therapy for recessive diseases. Studies to date demonstrate that gene therapy in the eye is safe and can result in long-term recovery of visual function, but they also highlight that further research is required to identify optimum intervention time-points, target populations and the compatibility of associate therapies. This article is part of a directed issue entitled: Regenerative Medicine: the challenge of translation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Alternate bearing design fabrication and test program, exhibit B

NASA Technical Reports Server (NTRS)

1978-01-01

A 50 ft-lb-sec (FPS) reaction wheel was modified with an ironless armature brushless dc motor and a magnetic bearing suspension. The purpose was to demonstrate the performance of an alternate bearing concept, i.e., a magnetic bearing suspension, which could be used in Skylab type CMG's to meet the attitude control requirements of long term space stations. A magnetic suspension was built, installed and tested in the 50 FPS reaction wheel. A secondary effort included the build and test of a compatible reaction wheel motor. Performance characteristics of both are presented and discussed.

Plasma-surface interaction in the Be/W environment: Conclusions drawn from the JET-ILW for ITER

NASA Astrophysics Data System (ADS)

Brezinsek, S.; JET-EFDA contributors

2015-08-01

The JET ITER-Like Wall experiment (JET-ILW) provides an ideal test bed to investigate plasma-surface interaction (PSI) and plasma operation with the ITER plasma-facing material selection employing beryllium in the main chamber and tungsten in the divertor. The main PSI processes: material erosion and migration, (b) fuel recycling and retention, (c) impurity concentration and radiation have be1en studied and compared between JET-C and JET-ILW. The current physics understanding of these key processes in the JET-ILW revealed that both interpretation of previously obtained carbon results (JET-C) and predictions to ITER need to be revisited. The impact of the first-wall material on the plasma was underestimated. Main observations are: (a) low primary erosion source in H-mode plasmas and reduction of the material migration from the main chamber to the divertor (factor 7) as well as within the divertor from plasma-facing to remote areas (factor 30 - 50). The energetic threshold for beryllium sputtering minimises the primary erosion source and inhibits multi-step re-erosion in the divertor. The physical sputtering yield of tungsten is low as 10-5 and determined by beryllium ions. (b) Reduction of the long-term fuel retention (factor 10 - 20) in JET-ILW with respect to JET-C. The remaining retention is caused by implantation and co-deposition with beryllium and residual impurities. Outgassing has gained importance and impacts on the recycling properties of beryllium and tungsten. (c) The low effective plasma charge (Zeff = 1.2) and low radiation capability of beryllium reveal the bare deuterium plasma physics. Moderate nitrogen seeding, reaching Zeff = 1.6 , restores in particular the confinement and the L-H threshold behaviour. ITER-compatible divertor conditions with stable semi-detachment were obtained owing to a higher density limit with ILW. Overall JET demonstrated successful plasma operation in the Be/W material combination and confirms its advantageous PSI behaviour and gives strong support to the ITER material selection.

A low-cost Mr compatible ergometer to assess post-exercise phosphocreatine recovery kinetics.

PubMed

Naimon, Niels D; Walczyk, Jerzy; Babb, James S; Khegai, Oleksandr; Che, Xuejiao; Alon, Leeor; Regatte, Ravinder R; Brown, Ryan; Parasoglou, Prodromos

2017-06-01

To develop a low-cost pedal ergometer compatible with ultrahigh (7 T) field MR systems to reliably quantify metabolic parameters in human lower leg muscle using phosphorus magnetic resonance spectroscopy. We constructed an MR compatible ergometer using commercially available materials and elastic bands that provide resistance to movement. We recruited ten healthy subjects (eight men and two women, mean age ± standard deviation: 32.8 ± 6.0 years, BMI: 24.1 ± 3.9 kg/m 2 ). All subjects were scanned on a 7 T whole-body magnet. Each subject was scanned on two visits and performed a 90 s plantar flexion exercise at 40% maximum voluntary contraction during each scan. During the first visit, each subject performed the exercise twice in order for us to estimate the intra-exam repeatability, and once during the second visit in order to estimate the inter-exam repeatability of the time constant of phosphocreatine recovery kinetics. We assessed the intra and inter-exam reliability in terms of the within-subject coefficient of variation (CV). We acquired reliable measurements of PCr recovery kinetics with an intra- and inter-exam CV of 7.9% and 5.7%, respectively. We constructed a low-cost pedal ergometer compatible with ultrahigh (7 T) field MR systems, which allowed us to quantify reliably PCr recovery kinetics in lower leg muscle using 31 P-MRS.

Diffusion tensor and volumetric magnetic resonance imaging using an MR-compatible hand-induced robotic device suggests training-induced neuroplasticity in patients with chronic stroke

PubMed Central

LAZARIDOU, ASIMINA; ASTRAKAS, LOUKAS; MINTZOPOULOS, DIONYSSIOS; KHANICHEH, AZADEH; SINGHAL, ANEESH B.; MOSKOWITZ, MICHAEL A.; ROSEN, BRUCE; TZIKA, ARIA A.

2013-01-01

Stroke is the third leading cause of mortality and a frequent cause of long-term adult impairment. Improved strategies to enhance motor function in individuals with chronic disability from stroke are thus required. Post-stroke therapy may improve rehabilitation and reduce long-term disability; however, objective methods for evaluating the specific impact of rehabilitation are rare. Brain imaging studies on patients with chronic stroke have shown evidence for reorganization of areas showing functional plasticity after a stroke. In this study, we hypothesized that brain mapping using a novel magnetic resonance (MR)-compatible hand device in conjunction with state-of-the-art magnetic resonance imaging (MRI) can serve as a novel biomarker for brain plasticity induced by rehabilitative motor training in patients with chronic stroke. This hypothesis is based on the premises that robotic devices, by stimulating brain plasticity, can assist in restoring movement compromised by stroke-induced pathological changes in the brain and that these changes can then be monitored by advanced MRI. We serially examined 15 healthy controls and 4 patients with chronic stroke. We employed a combination of diffusion tensor imaging (DTI) and volumetric MRI using a 3-tesla (3T) MRI system using a 12-channel Siemens Tim coil and a novel MR-compatible hand-induced robotic device. DTI data revealed that the number of fibers and the average tract length significantly increased after 8 weeks of hand training by 110% and 64%, respectively (p<0.001). New corticospinal tract (CST) fibers projecting progressively closer to the motor cortex appeared during training. Volumetric data analysis showed a statistically significant increase in the cortical thickness of the ventral postcentral gyrus areas of patients after training relative to pre-training cortical thickness (p<0.001). We suggest that rehabilitation is possible for a longer period of time after stroke than previously thought, showing that structural plasticity is possible even after 6 months due to retained neuroplasticity. Our study is an example of personalized medicine using advanced neuroimaging methods in conjunction with robotics in the molecular medicine era. PMID:23982596

A new experimental method for the accelerated characterization of composite materials

NASA Technical Reports Server (NTRS)

Yeow, Y. T.; Morris, D. H.; Brinson, H. F.

1978-01-01

The use of composite materials for a variety of practical structural applications is presented and the need for an accelerated characterization procedure is assessed. A new experimental and analytical method is presented which allows the prediction of long term properties from short term tests. Some preliminary experimental results are presented.

Worldwide flight and ground-based exposure of composite materials

NASA Technical Reports Server (NTRS)

Dexter, H. B.; Baker, D. J.

1984-01-01

The long-term durability of those advanced composite materials which are applicable to aircraft structures was discussed. The composite components of various military and commercial aircraft and helicopters were reviewed. Both ground exposure and flight service were assessed in terms of their impact upon composite structure durability. The ACEE Program is mentioned briefly.

Long term monitoring of the optical background in the Capo Passero deep-sea site with the NEMO tower prototype

NASA Astrophysics Data System (ADS)

Adrián-Martínez, S.; Aiello, S.; Ameli, F.; Anghinolfi, M.; Ardid, M.; Barbarino, G.; Barbarito, E.; Barbato, F. C. T.; Beverini, N.; Biagi, S.; Biagioni, A.; Bouhadef, B.; Bozza, C.; Cacopardo, G.; Calamai, M.; Calì, C.; Calvo, D.; Capone, A.; Caruso, F.; Ceres, A.; Chiarusi, T.; Circella, M.; Cocimano, R.; Coniglione, R.; Costa, M.; Cuttone, G.; D'Amato, C.; D'Amico, A.; De Bonis, G.; De Luca, V.; Deniskina, N.; De Rosa, G.; di Capua, F.; Distefano, C.; Enzenhöfer, A.; Fermani, P.; Ferrara, G.; Flaminio, V.; Fusco, L. A.; Garufi, F.; Giordano, V.; Gmerk, A.; Grasso, R.; Grella, G.; Hugon, C.; Imbesi, M.; Kulikovskiy, V.; Lahmann, R.; Larosa, G.; Lattuada, D.; Leismüller, K. P.; Leonora, E.; Litrico, P.; Llorens Alvarez, C. D.; Lonardo, A.; Longhitano, F.; Lo Presti, D.; Maccioni, E.; Margiotta, A.; Marinelli, A.; Martini, A.; Masullo, R.; Migliozzi, P.; Migneco, E.; Miraglia, A.; Mollo, C. M.; Mongelli, M.; Morganti, M.; Musico, P.; Musumeci, M.; Nicolau, C. A.; Orlando, A.; Orzelli, A.; Papaleo, R.; Pellegrino, C.; Pellegriti, M. G.; Perrina, C.; Piattelli, P.; Pugliatti, C.; Pulvirenti, S.; Raffaelli, F.; Randazzo, N.; Real, D.; Riccobene, G.; Rovelli, A.; Saldaña, M.; Sanguineti, M.; Sapienza, P.; Sciacca, V.; Sgura, I.; Simeone, F.; Sipala, V.; Speziale, F.; Spitaleri, A.; Spurio, M.; Stellacci, S. M.; Taiuti, M.; Terreni, G.; Trasatti, L.; Trovato, A.; Ventura, C.; Vicini, P.; Viola, S.; Vivolo, D.

2016-02-01

The NEMO Phase-2 tower is the first detector which was operated underwater for more than 1 year at the "record" depth of 3500 m. It was designed and built within the framework of the NEMO (NEutrino Mediterranean Observatory) project. The 380 m high tower was successfully installed in March 2013 80 km offshore Capo Passero (Italy). This is the first prototype operated on the site where the Italian node of the KM3NeT neutrino telescope will be built. The installation and operation of the NEMO Phase-2 tower has proven the functionality of the infrastructure and the operability at 3500 m depth. A more than 1 year long monitoring of the deep water characteristics of the site has been also provided. In this paper the infrastructure and the tower structure and instrumentation are described. The results of long term optical background measurements are presented. The rates show stable and low baseline values, compatible with the contribution of ^{40}K light emission, with a small percentage of light bursts due to bioluminescence. All these features confirm the stability and good optical properties of the site.

Chemical Retraction Agents - in vivo and in vitro Studies into their Physico-Chemical Properties, Biocompatibility with Gingival Margin Tissues and Compatibility with Elastomer Impression Materials.

PubMed

Nowakowska, Danuta; Saczko, Jolanta; Kulbacka, Julita; Wicckiewicz, Wlodzimierz

2017-01-01

Gingival margin retraction/displacement (GMR/D) is a commonly accepted procedure in restorative dentistry. Of the various retraction methods, the chemo-mechanical approach with retraction media and chemical retraction agents (ChRAs) is mostly used. Different local and/or systemic side effects were observed after "chemical attacks" from these retraction agents. Moreover, no consensus exists as to the compatibility of chemical agents with different impression materials. This paper reports the findings of in vivo and in vitro studies and we discuss the physico-chemical properties of chemical retraction agents, their undesirable clinical side effects, biological activity and compatibility with selected groups of elastomer impression materials. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

On the Use of Accelerated Test Methods for Characterization of Advanced Composite Materials

NASA Technical Reports Server (NTRS)

Gates, Thomas S.

2003-01-01

A rational approach to the problem of accelerated testing for material characterization of advanced polymer matrix composites is discussed. The experimental and analytical methods provided should be viewed as a set of tools useful in the screening of material systems for long-term engineering properties in aerospace applications. Consideration is given to long-term exposure in extreme environments that include elevated temperature, reduced temperature, moisture, oxygen, and mechanical load. Analytical formulations useful for predictive models that are based on the principles of time-based superposition are presented. The need for reproducible mechanisms, indicator properties, and real-time data are outlined as well as the methodologies for determining specific aging mechanisms.

Development of high temperature liquid metal test facilities for qualification of materials and investigations of thermoelectrical modules

NASA Astrophysics Data System (ADS)

Onea, A.; Hering, W.; Reiser, J.; Weisenburger, A.; Diez de los Rios Ramos, N.; Lux, M.; Ziegler, R.; Baumgärtner, S.; Stieglitz, R.

2017-07-01

Three classes of experimental liquid metal facilities have been completed during the LIMTECH project aiming the qualification of materials, investigation of thermoelectrical modules, investigation of sodium transitional regimes and fundamental thermo-dynamical flows in concentrating solar power (CSP) relevant geometries. ATEFA facility is dedicated to basic science investigation focussed on the alkali metal thermal-to-electric converter (AMTEC) technology. Three SOLTEC facilities are aimed to be used in different laboratories for long term material investigation sodium environment up to a 1000 K temperature and for long term tests of AMTEC modules. The medium scale integral facility KASOLA is planned as the backbone for CSP development and demonstration.

Durability of aircraft composite materials

NASA Technical Reports Server (NTRS)

Dextern, H. B.

1982-01-01

Confidence in the long term durability of advanced composites is developed through a series of flight service programs. Service experience is obtained by installing secondary and primary composite components on commercial and military transport aircraft and helicopters. Included are spoilers, rudders, elevators, ailerons, fairings and wing boxes on transport aircraft and doors, fairings, tail rotors, vertical fins, and horizontal stabilizers on helicopters. Materials included in the evaluation are boron/epoxy, Kevlar/epoxy, graphite/epoxy and boron/aluminum. Inspection, maintenance, and repair results for the components in service are reported. The effects of long term exposure to laboratory, flight, and outdoor environmental conditions are reported for various composite materials. Included are effects of moisture absorption, ultraviolet radiation, and aircraft fuels and fluids.

An Improved Approach for Analyzing the Oxygen Compatibility of Solvents and other Oxygen-Flammable Materials for Use in Oxygen Systems

NASA Technical Reports Server (NTRS)

Harper, Susan A.; Juarez, Alfredo; Peralta, Stephen F.; Stoltzfus, Joel; Arpin, Christina Pina; Beeson, Harold D.

2016-01-01

Solvents used to clean oxygen system components must be assessed for oxygen compatibility, as incompatible residue or fluid inadvertently left behind within an oxygen system can pose a flammability risk. The most recent approach focused on solvent ignition susceptibility to assess the flammability risk associated with these materials. Previous evaluations included Ambient Pressure Liquid Oxygen (LOX) Mechanical Impact Testing (ASTM G86) and Autogenous Ignition Temperature (AIT) Testing (ASTM G72). The goal in this approach was to identify a solvent material that was not flammable in oxygen. As environmental policies restrict the available options of acceptable solvents, it has proven difficult to identify one that is not flammable in oxygen. A more rigorous oxygen compatibility approach is needed in an effort to select a new solvent for NASA applications. NASA White Sands Test Facility proposed an approach that acknowledges oxygen flammability, yet selects solvent materials based on their relative oxygen compatibility ranking, similar to that described in ASTM G63-99. Solvents are selected based on their ranking with respect to minimal ignition susceptibility, damage and propagation potential, as well as their relative ranking when compared with other solvent materials that are successfully used in oxygen systems. Test methods used in this approach included ASTM G86 (Ambient Pressure LOX Mechanical Impact Testing and Pressurized Gaseous Oxygen (GOX) Mechanical Impact Testing), ASTM G72 (AIT Testing), and ASTM D240 (Heat of Combustion (HOC) Testing). Only four solvents were tested through the full battery of tests for evaluation of oxygen compatibility: AK-225G as a baseline comparison, Solstice PF, L-14780, and Vertrel MCA. Baseline solvent AK-225G exhibited the lowest HOC and highest AIT of solvents tested. Nonetheless, Solstice PF, L-14780, and Vertrel MCA HOCs all fell well within the range of properties that are associated with proven oxygen system materials. Tested AITs for these solvents fell only slightly lower than the AIT for the proven AK-225G solvent. Based on these comparisons in which solvents exhibited properties within those ranges seen with proven oxygen system materials, it is believed that Solstice PF, L-14780, and Vertrel MCA would perform well with respect to oxygen compatibility.

Parametric Methods for Determining the Characteristics of Long-Term Metal Strength

NASA Astrophysics Data System (ADS)

Nikitin, V. I.; Rybnikov, A. I.

2018-06-01

A large number of parametric methods were proposed to calculate the characteristics of the long-term strength of metals. All of them are based on the fact that temperature and time are mutually compensating factors in the processes of metal degradation at high temperature under the action of a constant stress. The analysis of the well-known Larson-Miller, Dorn-Shcherby, Menson-Haferd, Graham-Wallace, and Trunin parametric equations is performed. The widely used Larson-Miller parameter was subjected to a detailed analysis. The application of this parameter to the calculation of ultimate long-term strength for steels and alloys is substantiated provided that the laws of exponential dependence on temperature and power dependence on strength for the heat resistance are observed. It is established that the coefficient C in the Larson- Miller equation is a characteristic of the heat resistance and is different for each material. Therefore, the use of a universal constant C = 20 in parametric calculations, as well as an a priori presetting of numerical C values for each individual group of materials, is unacceptable. It is shown in what manner it is possible to determine an exact value of coefficient C for any material of interest as well as to obtain coefficient C depending on stress in case such a dependence is manifested. At present, the calculation of long-term strength characteristics can be performed to a sufficient accuracy using Larson-Miller's parameter and its refinements described therein as well as on the condition that a linear law in logσ- P dependence is observed and calculations in the interpolation range is performed. The use of the presented recommendations makes it possible to obtain a linear parametric logσ- P dependence, which makes it possible to determine to a sufficient accuracy the values of ultimate long-term strength for different materials.

Nursing Home Insurance: Exploiting Fear for Profit? (An Examination of an Emerging Long-Term Care Insurance Market.) A Briefing Report by the Chairman of the Subcommittee on Health and Long-Term Care of the Select Committee on Aging. U.S. House of Representatives, One Hundredth Congress, First Session.

ERIC Educational Resources Information Center

Pepper, Claude

This report describes the activities of the United States House of Representatives Subcommittee on Health and Long-Term Care in its effort to examine abuses in the sale of nursing home insurance. Earlier Congressional studies of abuses in the sale of health insurance to the elderly are discussed as background material for the present…

Crystal River 3 Cable Materials for Thermal and Gamma Radiation Aging

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

Fifield, Leonard S.; Correa, Miguel; Zwoster, Andy

The Expanded Materials Degradation Assessment Volume 5: Aging of Cables and Cable Systems (EMDA) summarizes the state of knowledge of materials, constructions, operating environments, and aging behavior of low voltage and medium cables in nuclear power plants (NPPs) and identifies potential knowledge gaps with regard to cable operation beyond 60 years. The greatest area of uncertainty relates to how well the accelerated aging used in the original equipment qualification (EQ) processes predicts the performance of cable materials in extended operation. General opinion and utility experience have indicated that actual operating environments of in-plant cables are not as severe, however, asmore » the operating and design basis environments used in the qualification process. Better understanding of the long term aging behavior of cable insulation materials in service conditions and the analysis of actual cable operating environments are the objectives of ongoing research to support subsequent license renewal activities in particular and long term cable aging management in general. A key component of the effort to better understand cable material aging behavior is the availability of representative samples of cables that have been installed in operating light water reactors and have experienced long term service. Unique access to long term service cables, including relatively rich information on cable identity and history, occurred in 2016 through the assistance of the Electric Power Research Institute (EPRI). EPRI facilitated DOE receipt of harvested cables from the decommissioned Crystal River Unit 3 (CR3) pressurized water reactor representing six of the nine most common low voltage cable manufacturers (EPRI 103841R1): Rockbestos, Anaconda Wire and Cable Company (Anaconda), Boston Insulated Wire (BIW), Brand-Rex, Kerite and Okonite. Cable samples received had been installed in the operating plant for durations ranging from 10 years to 36 years. These cables provide the opportunity to assess actual in-plant material aging and compare it to the expectations for service aging implied in original equipment qualification. The received samples are from cables manufactured as early as 1971 and as late as 1998. Of the original manufacturers, BIW, Anaconda and Kerite no longer supply low-voltage cables to the nuclear industry. Okonite, Rockbestos, and Brand-Rex do still supply nuclear-grade low-voltage cables, but most cable insulation formulations have changed over the years. Thus the availability of the CR3 samples representative of cables installed in existing U.S. NPPs also presents the opportunity for additional aging studies on the most relevant insulation and jacketing materials. This report describes the cables received from CR3 through EPRI assistance, some of the specific knowledge gaps that study of these cable materials can be used to address, and experimental plans for addressing those gaps using these materials. Harvested cables from CR3 and other NPPs that have experienced long term service, new old stock cables (manufactured before 2000, but never put in service), and relevant modern nuclear cables and materials from cable manufacturers are enabling research to address identified knowledge gaps and better understand long term aging behavior for cable materials currently installed in NPPs. This research, combined with refined understanding of actual service environments and conditions, will both support subsequent licensing activities and more efficient plant cable aging management.« less

Plasma Sterilization Technology for Spacecraft Applications

NASA Technical Reports Server (NTRS)

Fraser, S. J.; Olson, R. L.; Leavens, W. M.

1975-01-01

The application of plasma gas technology to sterilization and decontamination of spacecraft components is considered. Areas investigated include: effective sterilizing ranges of four separate gases; lethal constituents of a plasma environment; effectiveness of plasma against a diverse group of microorganisms; penetrating efficiency of plasmas for sterilization; and compatibility of spacecraft materials with plasma environments. Results demonstrated that plasma gas, specifically helium plasma, is a highly effective sterilant and is compatible with spacecraft materials.

DEVELOPMENT OF A PORTABLE SOFTWARE LANGUAGE FOR PHYSIOLOGICALLY-BASED PHARMACOKINETIC (PBPK) MODELS

EPA Science Inventory

The PBPK modeling community has had a long-standing problem with modeling software compatibility. The numerous software packages used for PBPK models are, at best, minimally compatible. This creates problems ranging from model obsolescence due to software support discontinuation...

Opportunities for the LWR ATF materials development program to contribute to the LBE-cooled ADS materials qualification program

NASA Astrophysics Data System (ADS)

Gong, Xing; Li, Rui; Sun, Maozhou; Ren, Qisen; Liu, Tong; Short, Michael P.

2016-12-01

Accelerator-driven systems (ADS) are a promising approach for nuclear waste disposal. Nevertheless, the principal candidate materials proposed for ADS construction, such as the ferritic/martensitic steel, T91, and austenitic stainless steels, 316L and 15-15Ti, are not fully compatible with the liquid lead-bismuth eutectic (LBE) coolant. Under some operating conditions, liquid metal embrittlement (LME) or liquid metal corrosion (LMC) may occur in these steels when exposed to LBE. These environmentally-induced material degradation effects pose a threat to ADS reactor safety, as failure of the materials could initiate a severe accident, in which fission products are released into the coolant. Meanwhile, parallel efforts to develop accident-tolerant fuels (ATF) in light water reactors (LWRs) could provide both general materials design philosophies and specific material solutions to the ADS program. In this paper, the potential contributions of the ATF materials development program to the ADS materials qualification program are evaluated and discussed in terms of service conditions and materials performance requirements. Several specific areas where coordinated development may benefit both programs, including composite materials and selected coatings, are discussed.

Europa Propulsion Valve Seat Material Testing

NASA Technical Reports Server (NTRS)

Addona, Brad M.

2017-01-01

The Europa mission and spacecraft design presented unique challenges for selection of valve seat materials that met the fluid compatibility requirements, and combined fluid compatibility and high radiation exposure level requirements. The Europa spacecraft pressurization system valves will be exposed to fully saturated propellant vapor for the duration of the mission. The effects of Nitrogen Tetroxide (NTO) and Monomethylhydrazine (MMH) propellant vapors on heritage valve seat materials, such as Vespel SP-1 and Polychlorotrifluoroethylene (PCTFE), were evaluated to determine if an alternate material is required. In liquid system applications, Teflon is the only available compatible valve seat material. Radiation exposure data for Teflon in an air or vacuum environment has been previously documented. Radiation exposure data for Teflon in an oxidizer environment such as NTO, was not available, and it was unknown whether the effects would be similar to those on air-exposed samples. Material testing was conducted by Marshall Space Flight Center (MSFC) and White Sands Test Facility (WSTF) to determine the effects of propellant vapor on heritage seat materials for pressurization valve applications, and the effects of combined radiation and NTO propellant exposure on Teflon. The results indicated that changes in heritage pressurization valve seat materials' properties rendered them unsuitable for the Europa application. The combined radiation and NTO exposure testing of Teflon produced results equivalent to combined radiation and air exposure results.

Detailed analysis of acidic compounds in Mayan gas oil and hydrotreated products

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

Sturm, G.P. Jr.; Green, J.B.; Grigsby, R.D.

1989-04-01

The present and future importance of heavy crude as a primary energy resource is widely recognized in spite of the current oversupply of crude oil. Along with coal and shale oil, heavy crudes and heavy ends of conventional crude produced by primary and enhanced oil recovery methods are considered important and dependable resources to meet their nation's long-term energy needs. Heavy crudes impose more severe requirements upon refining technology to produce end products meeting current specifications in terms of stability, compatibility, and corrosiveness. This study is based on the premise that knowledge of the problem components in the feedstocks, intermediatemore » process streams, and products can aid in the development of efficient and economical means of producing higher quality products.« less

Hydrazine-Compatible Elastomer

NASA Technical Reports Server (NTRS)

Markles, O., F.; Dye, T. G.

1982-01-01

Hydrazine hardly reacts with ethylene propylene diene monomer, even at high temperatures. According to report to tests, EPDM is most hydrazine-compatible material among elastomers. Has strong potential as valve-seat and O-ring seal with hydrazine, especially at high temperatures.

Fully CMOS-compatible titanium nitride nanoantennas

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

Briggs, Justin A., E-mail: jabriggs@stanford.edu; Department of Materials Science and Engineering, Stanford University, 496 Lomita Mall, Stanford, California 94305; Naik, Gururaj V.

CMOS-compatible fabrication of plasmonic materials and devices will accelerate the development of integrated nanophotonics for information processing applications. Using low-temperature plasma-enhanced atomic layer deposition (PEALD), we develop a recipe for fully CMOS-compatible titanium nitride (TiN) that is plasmonic in the visible and near infrared. Films are grown on silicon, silicon dioxide, and epitaxially on magnesium oxide substrates. By optimizing the plasma exposure per growth cycle during PEALD, carbon and oxygen contamination are reduced, lowering undesirable loss. We use electron beam lithography to pattern TiN nanopillars with varying diameters on silicon in large-area arrays. In the first reported single-particle measurements onmore » plasmonic TiN, we demonstrate size-tunable darkfield scattering spectroscopy in the visible and near infrared regimes. The optical properties of this CMOS-compatible material, combined with its high melting temperature and mechanical durability, comprise a step towards fully CMOS-integrated nanophotonic information processing.« less

Environmentally compatible hand wipe cleaning solvents

NASA Technical Reports Server (NTRS)

Clayton, Catherine P.; Kovach, Michael P.

1995-01-01

Several solvents of environmental concern have previously been used for hand wipe cleaning of SRB surfaces, including 1,1,1-trichloroethane, perchloroethylene, toluene, xylene, and MEK. USBI determined the major types of surfaces involved, and qualification requirements of replacement cleaning agents. Nineteen environmentally compatible candidates were tested on 33 material substrates with 26 types of potential surface contaminants, involving over 7,000 individual evaluations. In addition to the cleaning performance evaluation, bonding, compatibility, and corrosion tests were conducted. Results showed that one cleaner was not optimum for all surfaces. In most instances, some of the candidates cleaned better than the 1,1,1-trichloroethane baseline control. Aqueous cleaners generally cleaned better, and were more compatible with nonmetallic materials, such as paints, plastics, and elastomers. Organic base cleaners were better on metal surfaces. Five cleaners have been qualified and are now being implemented in SRB hand wipe cleaning operations.

Design of Composite Hip Prostheses Considering the Long-Term Behavior of the Femur

NASA Astrophysics Data System (ADS)

Lim, Jong Wan; Jeong, Jae Youn; Ha, Sung Kyu

A design method for the hip prosthesis is proposed which can alleviate problems associated with stress shielding, proximal loosening and the high stress of bone-implant interfaces after total hip replacement. The stress shielding which may lead to bone resorption, can cause a loosening of the stem and a fracture of femoral bone. Generally the composites were more suitable for hip prosthesis material in the long-term stability than metallic alloy because design cases of composite materials produced less stress shielding than titanium alloy. A bone remodeling algorithm was implemented in a nonlinear finite element program to predict the long-term performance of the hip prosthesis. The three neck shapes and three cross sections of composite hip were examined. It was found that the stress concentration in the distal region of the titanium stem which may cause the patient's thigh pains was reduced using composite material. The head neck shape was closely related with the cortical bone resorption and the cancellous bone apposition at proximal region whereas the cross-section was closely related with the relative micromotion between interfaces. The convex head neck type with the quadrangle cross-section produced less subsidence at proximal region on the medial side than the others. For all composite material cases, the cancellous bone apposition occurred at partial interfaces, which may result in a stable bio-fixation. The design performances of the convex neck head type with the hexagonal cross-section designed to insure the long-term stability were found to be more suitable than the others.

Crosslink Density and Molecular Weight Effects on the Viscoelastic Response of a Glassy High-Performance Polyimide

NASA Technical Reports Server (NTRS)

Nicholson, Lee M.; Whitley, Karen S.; Gates, Thomas S.

2001-01-01

Durability and long-term performance are among the primary concerns for the use of advanced polymer matrix composites (PMCs) in modern aerospace structural applications. For a PMC subJected to long-term exposure at elevated temperatures. the viscoelastic nature of the polymer matrix will contribute to macroscopic changes in composite stiffness, strength and fatigue life. Over time. changes in the polymer due to physical aging will have profound effects on tile viscoelastic compliance of the material, hence affecting its long-term durability. Thus, the ability to predict material performance using intrinsic properties, such as crosslink density and molecular weight, would greatly enhance the efficiency of design and development of PMCs. The objective of this paper is to discuss and present the results of an experimental study that considers the effects of crosslink density, molecular weight and temperature on the viscoelastic behavior including physical aging of an advanced polymer. Five distinct variations in crosslink density were used to evaluate the differences in mechanical performance of an advanced polyimide. The physical aging behavior was isolated by conducting sequenced, short-term isothermal creep compliance tests in tension. These tests were performed over a range of sub-glass transition temperatures. The material constants, material master curves and physical aging-related parameters were evaluated as a function of temperature crosslink density and molecular weight using time-temperature and time-aging time superposition techniques.

Georgia Long-Term Pavement Performance (GALTPP) Program – Maintaining Georgia’s Calibration Sites and Identifying the Potential for Using MEPDG for Characterization of Non-Standard Materials and Methods (Phase 1)

DOT National Transportation Integrated Search

2016-10-01

The Georgia Department of Transportation (GDOT) has initiated a Georgia Long-Term Pavement Performance (GALTPP) monitoring program 1) to provide data for calibrating the prediction models in the AASHTO Mechanistic-Empirical Pavement Design Guide (MEP...

Long-Term Experiences in Cash and Counseling for Young Adults with Intellectual Disabilities: Familial Programme Representative Descriptions

ERIC Educational Resources Information Center

Harry, Melissa L.; MacDonald, Lynn; McLuckie, Althea; Battista, Christina; Mahoney, Ellen K.; Mahoney, Kevin J.

2017-01-01

Background: Our aim was to explore previously unknown long-term outcomes of self-directed personal care services for young adults with intellectual disabilities and limitations in activities of daily living. Materials and Methods: The present authors utilized participatory action research and qualitative content analysis in interviewing 11 unpaid…

Alzheimer's Disease, Long-Term Care, and Health Policy: Who's Going To Pay the Bill?

ERIC Educational Resources Information Center

Monath, Jennifer

1997-01-01

Discusses the disparity in research funding for Alzheimer's Disease (AD), the future of health-care policy and the need for reform. Provides an annotated bibliography of sources related to AD, long-term care, and health policy. The types of documents covered include journals, government documents, and grey literature (material not readily…

Effective Instruction for STEM Disciplines: From Learning Theory to College Teaching

ERIC Educational Resources Information Center

Mastascusa, Edward J.; Snyder, William J.; Hoyt, Brian S.

2011-01-01

This groundbreaking book offers information on the most effective ways that students process material, store it in their long-term memories, and how that effects learning for long-term retention. It reveals how achieving different levels is important for "transfer" which refers to the learner's ability to use what is learned in different…

Comparison of continuous in-situ CO2 observations at Jungfraujoch using two different measurement techniques

NASA Astrophysics Data System (ADS)

Schibig, M. F.; Steinbacher, M.; Buchmann, B.; van der Laan-Luijkx, I. T.; van der Laan, S.; Ranjan, S.; Leuenberger, M. C.

2014-07-01

Since 2004, atmospheric carbon dioxide (CO2) is measured at the High Altitude Research Station Jungfraujoch by the division of Climate and Environmental Physics at the University of Bern (KUP) using a nondispersive infrared gas analyzer (NDIR) in combination with a paramagnetic O2 analyzer. In January 2010, CO2 measurements based on cavity ring down spectroscopy (CRDS) as part of the Swiss National Air Pollution Monitoring Network have been added by the Swiss Federal Laboratories for Materials Science and Technology (Empa). To ensure a smooth transition - a prerequisite when merging two datasets e.g. for trend determinations - the two measurement systems run in parallel for several years. Such a long-term intercomparison also allows identifying potential offsets between the two datasets and getting information about the compatibility of the two systems on different time scales. A good agreement of the seasonality as well as for the short-term variations was observed and to a lesser extent for trend calculations mainly due to the short common period. However, the comparison revealed some issues related to the stability of the calibration gases of the KUP system and their assigned CO2 mole fraction. It was possible to adapt an improved calibration strategy based on standard gas determinations, which lead to better agreement between the two data sets. By excluding periods with technical problems and bad calibration gas cylinders, the average hourly difference (CRDS - NDIR) of the two systems is -0.03 ppm ± 0.25 ppm. Although the difference of the two datasets is in line with the compatibility goal of ±0.1 ppm of the World Meteorological Organization (WMO), the standard deviation is still too high. A significant part of this uncertainty originates from the necessity to switch the KUP system frequently (every 12 min) for 6 min from ambient air to a working gas in order to correct short-term variations of the O2 measurement system. Allowing additionally for signal stabilization after switching the sample, an effective data coverage of only 1/6 for the KUP system is achieved while the Empa system has a nearly complete data coverage. Additionally, different internal volumes and flow rates between the two systems may affect observed differences.

Comparison of continuous in situ CO2 observations at Jungfraujoch using two different measurement techniques

NASA Astrophysics Data System (ADS)

Schibig, M. F.; Steinbacher, M.; Buchmann, B.; van der Laan-Luijkx, I. T.; van der Laan, S.; Ranjan, S.; Leuenberger, M. C.

2015-01-01

Since 2004, atmospheric carbon dioxide (CO2) is being measured at the High Altitude Research Station Jungfraujoch by the division of Climate and Environmental Physics at the University of Bern (KUP) using a nondispersive infrared gas analyzer (NDIR) in combination with a paramagnetic O2 analyzer. In January 2010, CO2 measurements based on cavity ring-down spectroscopy (CRDS) as part of the Swiss National Air Pollution Monitoring Network were added by the Swiss Federal Laboratories for Materials Science and Technology (Empa). To ensure a smooth transition - a prerequisite when merging two data sets, e.g., for trend determinations - the two measurement systems run in parallel for several years. Such a long-term intercomparison also allows the identification of potential offsets between the two data sets and the collection of information about the compatibility of the two systems on different time scales. A good agreement of the seasonality, short-term variations and, to a lesser extent mainly due to the short common period, trend calculations is observed. However, the comparison reveals some issues related to the stability of the calibration gases of the KUP system and their assigned CO2 mole fraction. It is possible to adapt an improved calibration strategy based on standard gas determinations, which leads to better agreement between the two data sets. By excluding periods with technical problems and bad calibration gas cylinders, the average hourly difference (CRDS - NDIR) of the two systems is -0.03 ppm ± 0.25 ppm. Although the difference of the two data sets is in line with the compatibility goal of ±0.1 ppm of the World Meteorological Organization (WMO), the standard deviation is still too high. A significant part of this uncertainty originates from the necessity to switch the KUP system frequently (every 12 min) for 6 min from ambient air to a working gas in order to correct short-term variations of the O2 measurement system. Allowing additional time for signal stabilization after switching the sample, an effective data coverage of only one-sixth for the KUP system is achieved while the Empa system has a nearly complete data coverage. Additionally, different internal volumes and flow rates may affect observed differences.

Long-term strength determination for cooled blades made of monocrystalline superalloys

NASA Astrophysics Data System (ADS)

Getsov, L. B.; Semenov, A. S.; Besschetnov, V. A.; Grishchenko, A. I.; Semenov, S. G.

2017-04-01

For the manufacture of blades for modern gas-turbine installations, monocrystalline alloys are used. Traditional methods for the calculation of stressed-deformed state and safety factors for these alloys developed and verified for polycrystalline materials need to be adjusted. This paper deals with methodological principles for an approach to the solving of the problem concerning a finite-element determination of the long-term static strength for cooled monocrystalline blades employed in gas-turbine installations based on the use of two different models (phenomenological and micromechanical) considering the inelastic deformation of monocrystalline superalloys. An analysis has been performed for the distribution of Schmid factors in the spherical triangle for primary and secondary octahedral and cubic slip systems. Calculations are performed using Larson-Miller's parametric dependences taking into account the crystallographic orientation of the material. A determination procedure for the anisotropy coefficients of long-term strength is described based on data for different orientations. A comparative analysis of the results of finite-element calculations made using phenomenological and micromechanical (crystallographic) creep models for the long-term static strength of cooled monocrystalline blades used in a gas-turbine engine has been performed. It is shown that the location of the most loaded sections of such a blade coincide with the results of calculations according to these models. It has been found that the micromechanical deformation model results in the obtaining of the most conservative estimate for the long-term strength of turbine blades made of monocrystalline alloys. It is shown that the calculations using models for materials with isotropic properties can produce considerable errors in determining the durability of the blades. The possibility is considered for using 1D-, 2D-, and 3D-models for turbine monocrystalline blades in the determination of their durability parameters.

Long-term monitoring of mechanical properties of FRP repair materials.

DOT National Transportation Integrated Search

2013-07-01

Fiber- reinforced polymer composites (FRP) are an attractive repair option for existing concrete structures. : CDOT has used this material on some projects, in particular the repair of the Castlewood Canyon Bridge in : 2003. Further use of the materi...

Long-term surveillance plan for the Green River, Utah, disposal site

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

NONE

1997-06-01

The long-term surveillance plan (LTSP) for the Green River, Utah, Uranium Mill Tailings Remedial Action (UMTRA) Project disposal site describes the surveillance activities for the Green River disposal cell. The U.S. Department of Energy (DOE) will carry out these activities to ensure that the disposal cell continues to function as designed. This final LTSP was prepared as a requirement for acceptance under the U.S. Nuclear Regulatory Commission (NRC) general license for custody and long-term care of residual radioactive materials (RRM). This LTSP documents whether the land and interests are owned by the United States or an Indian tribe and detailsmore » how the long-term care of the disposal site will be carried out. The Green River, Utah, LTSP is based on the DOE`s Guidance for Implementing the UMTRA Project Long-term Surveillance Program (DOE, 1992a).« less

A Comparison of Tension and Compression Creep in a Polymeric Composite and the Effects of Physical Aging on Creep Behavior

NASA Technical Reports Server (NTRS)

Gates, Thomas S.; Veazie, David R.; Brinson, L. Catherine

1996-01-01

Experimental and analytical methods were used to investigate the similarities and differences of the effects of physical aging on creep compliance of IM7/K3B composite loaded in tension and compression. Two matrix dominated loading modes, shear and transverse, were investigated for two load cases, tension and compression. The tests, run over a range of sub-glass transition temperatures, provided material constants, material master curves and aging related parameters. Comparing results from the short-term data indicated that although trends in the data with respect to aging time and aging temperature are similar, differences exist due to load direction and mode. The analytical model used for predicting long-term behavior using short-term data as input worked equally as well for the tension or compression loaded cases. Comparison of the loading modes indicated that the predictive model provided more accurate long term predictions for the shear mode as compared to the transverse mode. Parametric studies showed the usefulness of the predictive model as a tool for investigating long-term performance and compliance acceleration due to temperature.

Channel electron multiplier compatibility with Viton and Apiezon-L vacuum grease

NASA Astrophysics Data System (ADS)

McComas, D. J.; Baldonado, J. R.; Bame, S. J.; Barraclough, B. L.

1987-12-01

Clean Viton and Viton coated with Apiezon-L vacuum grease were tested for their noncontaminating compatibility with channel electron multipliers (CEMs). The test setup and procedure were the same as those used previously in conjunction with CEM compatibility tests of certain epoxies, solder, and fluorocarbon polymer materials useful for construction of spaceflight sensors. While some CEM gain degradation was noted during exposure to Viton and Apiezon-L, the present tests indicate that, at least over instrument lifetimes of about 2 x 10 to the 12th counts, these materials should be suitable for (1) preflight space sensor testing systems, (2) hermetic seals for CEM-based space sensors, and (3) terrestrial CEM-based instrumentation.