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Sample records for cathode long-term stability

  1. Long-Term Stability of LSM-YSZ Based Cathodes

    DEFF Research Database (Denmark)

    Baqué, Laura; Jørgensen, Peter Stanley; Hansen, Karin Vels

    2013-01-01

    A transmission line based model was successfully applied to study the ageing effect in LSM-YSZ cathodes after being exposed to humidified air at 900 °C for up to 3000 h. A decrease in the YSZ conductivity was correlated with the formation of the less conducting monoclinic zirconia. The amount of La...

  2. OPTIMIZATION OF THE CATHODE LONG-TERM STABILITY IN MOLTEN CARBONATE FUEL CELLS: EXPERIMENTAL STUDY AND MATHEMATICAL MODELING

    Energy Technology Data Exchange (ETDEWEB)

    Hector Colonmer; Prabhu Ganesan; Nalini Subramanian; Dr. Bala Haran; Dr. Ralph E. White; Dr. Branko N. Popov

    2002-09-01

    This project focused on addressing the two main problems associated with state of art Molten Carbonate Fuel Cells, namely loss of cathode active material and stainless steel current collector deterioration due to corrosion. We followed a dual approach where in the first case we developed novel materials to replace the cathode and current collector currently used in molten carbonate fuel cells. In the second case we improved the performance of conventional cathode and current collectors through surface modification. States of art NiO cathode in MCFC undergo dissolution in the cathode melt thereby limiting the lifetime of the cell. To prevent this we deposited cobalt using an electroless deposition process. We also coated perovskite (La{sub 0.8}Sr{sub 0.2}CoO{sub 3}) in NiO thorough a sol-gel process. The electrochemical oxidation behavior of Co and perovskites coated electrodes is similar to that of the bare NiO cathode. Co and perovskite coatings on the surface decrease the dissolution of Ni into the melt and thereby stabilize the cathode. Both, cobalt and provskites coated nickel oxide, show a higher polarization compared to that of nickel oxide, which could be due to the reduced surface area. Cobalt substituted lithium nickel oxide (LiNi{sub 0.8}Co{sub 0.2}O{sub 2}) and lithium cobalt oxide were also studied. LiNi{sub x}Co{sub 1-x}O{sub 2} was synthesized by solid-state reaction procedure using lithium nitrate, nickel hydroxide and cobalt oxalate precursor. LiNi{sub x}Co{sub 1-x}O{sub 2} showed smaller dissolution of nickel than state of art nickel oxide cathode. The performance was comparable to that of nickel oxide. The corrosion of the current collector in the cathode side was also studied. The corrosion characteristics of both SS304 and SS304 coated with Co-Ni alloy were studied. This study confirms that surface modification of SS304 leads to the formation of complex scales with better barrier properties and better electronic conductivity at 650 C. A three

  3. Long term stability of power systems

    Energy Technology Data Exchange (ETDEWEB)

    Kundur, P.; Gao, B. [Powertech Labs. Inc., Surrey, BC (Canada)

    1994-12-31

    Power system long term stability is still a developing subject. In this paper we provide our perspectives and experiences related to long term stability. The paper begins with the description of the nature of the long term stability problem, followed by the discussion of issues related to the modeling and solution techniques of tools for long term stability analysis. Cases studies are presented to illustrate the voltage stability aspect and plant dynamics aspect of long term stability. (author) 20 refs., 11 figs.

  4. Long-Term Stability of Social Participation

    Science.gov (United States)

    Hyyppa, Markku T.; Maki, Juhani; Alanen, Erkki; Impivaara, Olli; Aromaa, Arpo

    2008-01-01

    The long-term stability of social participation was investigated in a representative urban population of 415 men and 579 women who had taken part in the nationwide Mini-Finland Health Survey in the years 1978-1980 and were re-examined 20 years later. Stability was assessed by means of the following tracking coefficients: kappa, proportion of…

  5. The long term stability of lidar calibrations

    DEFF Research Database (Denmark)

    Courtney, Michael; Gayle Nygaard, Nicolai

    Wind lidars are now used extensively for wind resource measurements. One of the requirements for the data to be accepted in support of project financing (so-called ‘banka-bility’) is to demonstrate the long-term stability of lidar cali-brations. Calibration results for six Leosphere WindCube li-dars......-ters pertaining in the different calibration periods. This is supported by sliding-window analyses of one lidar at one location where the same order of variation is observed as between pre-service and post-service calibrations....

  6. Long-Term Stability of Horseshoe Orbits

    CERN Document Server

    Ćuk, Matija; Holman, Matthew J

    2012-01-01

    Unlike Trojans, horseshoe coorbitals are not generally considered to be long-term stable (Dermott and Murray, 1981; Murray and Dermott, 1999). As the lifetime of Earth's and Venus's horseshoe coorbitals is expected to be about a Gyr, we investigated the possible contribution of late-escaping inner planet coorbitals to the lunar Late Heavy Bombardment. Contrary to analytical estimates, we do not find many horseshoe objects escaping after first 100 Myr. In order to understand this behaviour, we ran a second set of simulations featuring idealized planets on circular orbits with a range of masses. We find that horseshoe coorbitals are generally long lived (and potentially stable) for systems with primary-to-secondary mass ratios larger than about 1200. This is consistent with results of Laughlin and Chambers (2002) for equal-mass pairs or coorbital planets and the instability of Jupiter's horseshoe companions (Stacey and Connors, 2008). Horseshoe orbits at smaller mass ratios are unstable because they must approa...

  7. Long-term stability test of a triple GEM detector

    CERN Document Server

    Adak, R P; Das, S; Ghosal, D; Ghosh, S K; Mondal, A; Nag, D; Nayak, T K; Patra, R N; Prasad, S K; Raha, S; Sahu, P K; Sahu, S; Swain, S

    2016-01-01

    The main aim of the study is to perform the long-term stability test of gain of the single mask triple GEM detector. A simple method is used for this long- term stability test using a radioactive X-ray source with high activity. The test is continued till accumulation of charge per unit area > 12.0 mC/mm2. The details of the chamber fabrication, the test set-up, the method of measurement and the test results are presented in this paper.

  8. Long-term performance of activated carbon air cathodes with different diffusion layer porosities in microbial fuel cells

    KAUST Repository

    Zhang, Fang

    2011-08-01

    Activated carbon (AC) air-cathodes are inexpensive and useful alternatives to Pt-catalyzed electrodes in microbial fuel cells (MFCs), but information is needed on their long-term stability for oxygen reduction. AC cathodes were constructed with diffusion layers (DLs) with two different porosities (30% and 70%) to evaluate the effects of increased oxygen transfer on power. The 70% DL cathode initially produced a maximum power density of 1214±123mW/m 2 (cathode projected surface area; 35±4W/m 3 based on liquid volume), but it decreased by 40% after 1 year to 734±18mW/m 2. The 30% DL cathode initially produced less power than the 70% DL cathode, but it only decreased by 22% after 1 year (from 1014±2mW/m 2 to 789±68mW/m 2). Electrochemical tests were used to examine the reasons for the degraded performance. Diffusion resistance in the cathode was found to be the primary component of the internal resistance, and it increased over time. Replacing the cathode after 1 year completely restored the original power densities. These results suggest that the degradation in cathode performance was due to clogging of the AC micropores. These findings show that AC is a cost-effective material for oxygen reduction that can still produce ~750mW/m 2 after 1 year. © 2011 Elsevier B.V.

  9. A Long-term Mechanism Needed to Safeguard Financial Stability

    Institute of Scientific and Technical Information of China (English)

    何德旭

    2007-01-01

    In the post-WTO era, China has encountered new difficulties in maintaining financial stability. Quick fix and emergency measures can no longer be relied on in the long run, and therefore, a long-term mechanism of financial stability must be put in place. This article recommends that China should focus on furthering financial reform, accelerating financial innovation and improving the legal system to promote a strong and competitive finance industry that is less vulnerable to financial hazards.

  10. Long-term laser frequency stabilization using fiber interferometers

    CERN Document Server

    Kong, Jia; Jimenez-Martinez, Ricardo; Mitchell, Morgan W

    2014-01-01

    We report long-term laser frequency stabilization using only the target laser and a pair of 5 m fiber interferometers, one as a frequency reference and the second as a sensitive thermometer. When used to stabilize a distributed feedback laser at 795 nm, the frequency Allan deviation at 1000 s drops from 5.6*10^{-8} to 6.9*10^{-10}. The performance equals that of an offset lock employing a second laser and an atomic reference.

  11. Long-term laser frequency stabilization using fiber interferometers

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Jia, E-mail: jia.kong@icfo.es [ICFO – Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels, Barcelona (Spain); Quantum Institute for Light and Atoms, Department of Physics, State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062 (China); Lucivero, Vito Giovanni; Jiménez-Martínez, Ricardo [ICFO – Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels, Barcelona (Spain); Mitchell, Morgan W. [ICFO – Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels, Barcelona (Spain); ICREA – Institució Catalana de Recerca i Estudis Avançats, 08015 Barcelona (Spain)

    2015-07-15

    We report long-term laser frequency stabilization using only the target laser and a pair of 5 m fiber interferometers, one as a frequency reference and the second as a sensitive thermometer to stabilize the frequency reference. When used to stabilize a distributed feedback laser at 795 nm, the frequency Allan deviation at 1000 s drops from 5.6 × 10{sup −8} to 6.9 × 10{sup −10}. The performance equals that of an offset lock employing a second, atom-stabilized laser in the temperature control.

  12. Related Studies in Long Term Lithium Battery Stability

    Science.gov (United States)

    Horning, R. J.; Chua, D. L.

    1984-01-01

    The continuing growth of the use of lithium electrochemical systems in a wide variety of both military and industrial applications is primarily a result of the significant benefits associated with the technology such as high energy density, wide temperature operation and long term stability. The stability or long term storage capability of a battery is a function of several factors, each important to the overall storage life and, therefore, each potentially a problem area if not addressed during the design, development and evaluation phases of the product cycle. Design (e.g., reserve vs active), inherent material thermal stability, material compatibility and self-discharge characteristics are examples of factors key to the storability of a power source.

  13. Long-term stability of orbits in storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Warnock, R.L.; Ruth, R.D.

    1990-06-01

    We describe a numerical method to establish long-term bounds on nonlinear Hamiltonian motion. By bounding the change in a nearly constant action variable, uniformly in initial condition, one can predict stability for N turns by tracking many orbits for a member of turns of N{sub 0} much less than N. In a first application to a model sextupole lattice in a region of strong nonlinearity, we predict stability of betatron motion in two degrees of freedom for 10{sup 8} turns. 5 refs., 3 figs.

  14. Long Term Stability of Coriolis Flow Meters: DESY experience

    Science.gov (United States)

    Boeckmann, T.; Bozhko, Y.; Escherich, K.; Petersen, B.; Putselyk, S.; Schnautz, T.; Sellmann, D.; Zhirnov, A.

    2017-02-01

    The measurement of coolant flow is important operational parameter for reliable operation of cryogenic system with superconducting magnets or cavities as well as for the system diagnostics in case of non-steady-state operation, e.g. during cool-down/warm-up or other transients. Proper flowmeter is chosen according to the different parameters, e.g. turn-down, operating temperature range, leak-tightness, pressure losses, long-term stability, etc. For helium cryogenics, the Venturi tube or Orifice, as well as Coriolis flow meters are often applied. For the present time, the orifices are usually used due to their simplicity and low costs, however, low turn-down range, large pressure drop, restriction of flow area, susceptibility to thermoacoustic oscillations limit their useful operation range. Operational characteristics of Venturi tubes is substantially improved in comparison to orifices, however, relative high costs and susceptibility to thermoacoustic oscillations still limit their application to special cases. The Coriolis flow meters do not have typical drawbacks of Venturi tube and orifices, however long-term stability over many years was not demonstrated yet. This paper describes the long-term behaviour of Coriolis flow meters after many years of operation at AMTF and XMTS facilities.

  15. Long term stability of cannabis resin and cannabis extracts

    DEFF Research Database (Denmark)

    Lindholst, Christian

    2010-01-01

      The aim of the present study was to investigate the stability of cannabinoids in cannabis resin slabs and cannabis extracts upon long-term storage. The levels of tetrahydrocannabinol (THC), cannabinol (CBN), cannabidiol (CBD) and cannabigerol (CBG) on both neutral and acidic form were measured...... stored in extracted form at room temperature the degradation rate of acidic THC increased significantly relative to resin material with concentration halve-lives of 35 and 91 days in daylight and darkness, respectively. Once cannabis material is extracted into organic solvents, care should be taken...

  16. Assessing colloidal stability of long term MWCNT based nanofluids.

    Science.gov (United States)

    Lamas, Bruno; Abreu, Bruno; Fonseca, Alexandra; Martins, Nelson; Oliveira, Mónica

    2012-09-01

    This report presents an assessment on colloidal stability of functionalized multiwalled carbon nanotubes based nanofluids. To this end, an innovative technique that allows for measurement of settling velocity during centrifugation is applied. This method also enables measurements without dilution, inferring further accuracy to the experimental study. The results suggest that functionalization techniques enable the production of highly stable nanofluids. It is also found, that the colloidal stabilities of these nanofluids are characterized by hindered settling. The settling velocity decreases when the nanoparticles volume fraction rises from 0.25% to 1.50% due to the increase of interparticle interaction. Furthermore, a high aspect ratio of nanoparticles directly contributed to an increase in colloidal stability. It is expected that these results may significantly contribute to proper tailor of nanofluids engineering, ensuring a long term stable dispersion enhancing industrial application suitability.

  17. Effects of cathode electrolyte interfacial (CEI) layer on long term cycling of all-solid-state thin-film batteries

    Science.gov (United States)

    Wang, Ziying; Lee, Jungwoo Z.; Xin, Huolin L.; Han, Lili; Grillon, Nathanael; Guy-Bouyssou, Delphine; Bouyssou, Emilien; Proust, Marina; Meng, Ying Shirley

    2016-08-01

    All-solid-state lithium-ion batteries have the potential to not only push the current limits of energy density by utilizing Li metal, but also improve safety by avoiding flammable organic electrolyte. However, understanding the role of solid electrolyte - electrode interfaces will be critical to improve performance. In this study, we conducted long term cycling on commercially available lithium cobalt oxide (LCO)/lithium phosphorus oxynitride (LiPON)/lithium (Li) cells at elevated temperature to investigate the interfacial phenomena that lead to capacity decay. STEM-EELS analysis of samples revealed a previously unreported disordered layer between the LCO cathode and LiPON electrolyte. This electrochemically inactive layer grew in thickness leading to loss of capacity and increase of interfacial resistance when cycled at 80 °C. The stabilization of this layer through interfacial engineering is crucial to improve the long term performance of thin-film batteries especially under thermal stress.

  18. Examining the long-term stability of overgeneral autobiographical memory.

    Science.gov (United States)

    Sumner, Jennifer A; Mineka, Susan; Zinbarg, Richard E; Craske, Michelle G; Vrshek-Schallhorn, Suzanne; Epstein, Alyssa

    2014-01-01

    Overgeneral autobiographical memory (OGM) is a proposed trait-marker for vulnerability to depression, but relatively little work has examined its long-term stability. This study investigated the stability of OGM over several years in 271 late adolescents and young adults participating in a larger longitudinal study of risk for emotional disorders. The Autobiographical Memory Test (AMT) was administered twice, with test-retest intervals ranging from approximately 3 to 6 years. There was evidence of significant but modest stability in OGM over several years. Specifically, Spearman rank correlations (ρs) between the proportions of specific and categoric memories generated on the two AMTs were .31 and .32, respectively. We did not find evidence that the stability of OGM was moderated by the length of the test-retest interval. Furthermore, the stability coefficients for OGM for individuals with and without a lifetime history of major depressive disorder (MDD) were relatively similar in magnitude and not significantly different from one another (ρs=.34 and .42 for the proportions of specific and categoric memories for those with a history of MDD; ρs=.31 for both the proportions of specific and categoric memories for those without a history of MDD). Implications for the conceptualisation of OGM are discussed.

  19. Long-Term Physical Stability of Plasticized Hemicellulose Films

    Directory of Open Access Journals (Sweden)

    Susanna L. Heikkinen

    2013-12-01

    Full Text Available Oat spelt arabinoxylan (OsAX and spruce galactoglucomannan (GGM are hemicelluloses that can be extracted in large quantities from side-streams of the agriculture and forest industries. They both form self-standing films, making them potential future packaging materials. This systematic study focuses on the effect of long-term storage on the physical stability of hemicellulose-based films. OsAX and GGM films were plasticized with 40% (w/w of the polysaccharide of glycerol, sorbitol, or their blends, and their stability was followed for four months. Ageing especially affected the glycerol-containing films, in which the tensile strength and Young’s modulus increased and elongation at break decreased. Although the mechanical properties were altered, storage did not affect crystallinity of the films. Oxygen gas permeability (OP and water vapor permeability (WVP properties were monitored in OsAX films. Interestingly WVP decreased during storage; more than a 40% decrease was seen when plasticizer blends contained 50% or more glycerol. In contrast, there were no drastic changes in the OP during storage; all the OPs obtained were between 3.7 and 8.9 [cm3 µm/ (m2 d kPa].

  20. Long-term evolution and stability of planetary systems

    Science.gov (United States)

    Juric, Mario

    This dissertation studies the dynamical evolution and stability of planetary systems over long time spans (10 8 -10 9 years). I investigated the dynamical evolution of few-planet systems by simulating ensembles of systems consisting of hundreds to thousands of randomly constructed members. I looked at ways to classify the systems according to their dynamical activity, and found the median Hill separation of an ensemble to be a sufficiently good criterion for separation into active (those exhibiting frequent planetary close encounters, collisions or ejections) and inactive ensembles. I examined the evolution of dynamical parameters in active systems. I found that in ensembles of dynamically active (initially unstable) systems the eccentricity distribution evolves towards the same equilibrium form, irrespective of the distribution it began with. Furthermore, this equilibrium distribution is indistinguishable, within observational errors, from the distribution found in extrasolar planets. This is to my knowledge the first successful detailed theoretical reproduction of the form of observed exoplanet eccentricity distribution. I further looked for quantities that can be used as indicators of long-term stability of planetary systems, specifically the angular momentum deficit (AMD) as originally proposed by Laskar. I found that the quantity Q , defined as the ratio of minimum AMD required for a planetary collision to occur in secular theory and the total AMD of the system, may be used to predict the likelihood of decay of a planetary system. Qualitatively, the decay in systems having Q [Special characters omitted.] 1 is highly probable, while systems with Q [Special characters omitted.] 1 were found to be stable. To conduct the above investigations, I developed a new integrator package (VENUS), and the HYBRID/EE integration scheme designed for nearly-symplectic long-term integrations. VENUS implements integration algorithms for few-body planetary system integrations

  1. Long-term stability of the APS storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Friedsam, H.; Penicka, M.; Error, J.

    1999-10-26

    The Advanced Photon Source (APS), a third-generation synchrotrons light source, was commissioned in 1995 at Argonne ''National Laboratory and has been fully-operational for beamline users since 1997. The APS storage ring can accommodate up to 68 user beamlines; about 70% of the available beamlines are currently in use by various collaborative access teams (CATS). The 7-GeV synchrotrons light source produces light in the soft to hard x-ray range that is used for research in such areas as x-ray instrumentation; material, chemical and atomic sciences; biology; and geo/soil/ environmental sciences. For the successful operation of an x-ray light source such as the Advanced Photon Source, the long-term stability of the concrete floor supporting the beam components and user beamlines is crucial. Settlements impact the orbit and location of the x-ray source points as well as the position of the x-ray beamlines. This paper compares the results of two successive resurveys of the APS accelerator components performed in 1995 and 1998.

  2. Long-term stability of TES satellite radiance measurements

    Directory of Open Access Journals (Sweden)

    T. C. Connor

    2011-07-01

    Full Text Available The utilization of Tropospheric Emission Spectrometer (TES Level 2 (L2 retrieval products for the purpose of assessing long term changes in atmospheric trace gas composition requires knowledge of the overall radiometric stability of the Level 1B (L1B radiances. The purpose of this study is to evaluate the stability of the radiometric calibration of the TES instrument by analyzing the difference between measured and calculated brightness temperatures in selected window regions of the spectrum. The Global Modeling and Assimilation Office (GMAO profiles for temperature and water vapor and the Real-Time Global Sea Surface Temperature (RTGSST are used as input to the Optimal Spectral Sampling (OSS radiative transfer model to calculate the simulated spectra. The TES reference measurements selected cover a 4-year period of time from mid 2005 through mid 2009 with the selection criteria being; observation latitudes greater than −30° and less than 30°, over ocean, Global Survey mode (nadir view and retrieved cloud optical depth of less than or equal to 0.01. The TES cloud optical depth retrievals are used only for screening purposes and no effects of clouds on the radiances are included in the forward model. This initial screening results in over 55 000 potential reference spectra spanning the four year period. Presented is a trend analysis of the time series of the residuals (observation minus calculations in the TES 2B1, 1B2, 2A1, and 1A1 bands, with the standard deviation of the residuals being approximately equal to 0.6 K for bands 2B1, 1B2, 2A1, and 0.9 K for band 1A1. The analysis demonstrates that the trend in the residuals is not significantly different from zero over the 4-year period. This is one method used to demonstrate that the relative radiometric calibration is stable over time, which is very important for any longer term analysis of TES retrieved products (L2, particularly well-mixed species such as carbon dioxide and methane.

  3. Long-term Stability of 9- to 12 % Cr Steels

    DEFF Research Database (Denmark)

    Hald, John

    2004-01-01

    of Mo with 1.8 % W combined with a slight amount of Boron led to steel P 92. The creep rupture strength of these new alloys are now secured with long-term tests up to 100,000 hours, which demonstrate improvements of 50% (P 91), 75 % (E 911) and 100 % (P 92) in strength compared to X 20CrMoV12 1....... and pressures. Newly developed steam pipe steels are based on modifications of well-established steels like the X 20CrMoV12 1. Balanced addition of V, Nb and N to a 9Cr 1 Mo steel led to the Modified 9 Cr steel P 91. Addition of 1% W to a 9Cr 1 MoVNbN base composition led to steel E 911 and partial replacement......In the recent 25 years creep rupture strength of 9- to 12 %Cr steels for steam pipes and turbines has been doubled by development of new alloys. This development has formed a basis for improved efficiency of fossil fired steam power plants by introduction of advanced steam temperatures...

  4. The long-term stability of cement - Leaching tests

    Energy Technology Data Exchange (ETDEWEB)

    Engkvist, I.; Albinsson, Y.; Johansson Engkvist, W. [Chalmers Univ. of Technology, Goeteborg (Sweden)

    1996-06-01

    The concrete construction in the Swedish repository for long-lived low and intermediate level waste will give a stable chemical near field environment for 10{sup 5} years. The pH is expected to exceed 12 for the life time for most of the radionuclides in the repository in both saline and non-saline groundwaters. This is shown by static leaching experiments performed in saline and non-saline granitic groundwater conditions. Five gram portions of crushed ordinary Portland cement paste were equilibrated with 20 ml of synthetic saline or non-saline groundwater in a nitrogen atmosphere. Each week 12 ml (60%) of the water was replaced. The withdrawn water was used for chemical analyses and the results were used to monitor the degradation of the cement paste. After eighty weeks, some samples were analysed for mineral composition and compared with the original unleached paste. The results indicated no secondary ettringite or calcite formation. The results also supported the conclusion that the salinity of the contacting water is of minor importance for the long-term performance of the cement paste. 18 refs, 32 figs.

  5. Long-term optical stability of fluorescent solar concentrator plates

    NARCIS (Netherlands)

    Slooff, Lenneke H.; Bakker, Nicolaas J.; Sommeling, Paul M.; Büchtemann, Andreas; Wedel, Armin; Van Sark, Wilfried G J H M

    2014-01-01

    Fluorescent solar concentrators offer an alternative approach for low-cost photovoltaic energy conversion. For successful application, not only the power conversion efficiency and cost are important, but also lifetime or stability of the devices. As today's concentrator is made of polymer sheets con

  6. Long-term cathode performance and the microbial communities that develop in microbial fuel cells fed different fermentation endproducts

    KAUST Repository

    Kiely, Patrick D.

    2011-01-01

    To better understand how cathode performance and substrates affected communities that evolved in these reactors over long periods of time, microbial fuel cells were operated for more than 1year with individual endproducts of lignocellulose fermentation (acetic acid, formic acid, lactic acid, succinic acid, or ethanol). Large variations in reactor performance were primarily due to the specific substrates, with power densities ranging from 835±21 to 62±1mW/m3. Cathodes performance degraded over time, as shown by an increase in power of up to 26% when the cathode biofilm was removed, and 118% using new cathodes. Communities that developed on the anodes included exoelectrogenic families, such as Rhodobacteraceae, Geobacteraceae, and Peptococcaceae, with the Deltaproteobacteria dominating most reactors. Pelobacter propionicus was the predominant member in reactors fed acetic acid, and it was abundant in several other MFCs. These results provide valuable insights into the effects of long-term MFC operation on reactor performance. © 2010 Elsevier Ltd.

  7. Long-term stability of Cu surface nanotips

    Science.gov (United States)

    Jansson, V.; Baibuz, E.; Djurabekova, F.

    2016-07-01

    Sharp nanoscale tips on the metal surfaces of electrodes enhance locally applied electric fields. Strongly enhanced electric fields trigger electron field emission and atom evaporation from the apexes of nanotips. Together, these processes may explain electric discharges in the form of small local arcs observed near metal surfaces in the presence of electric fields, even in ultra-high vacuum conditions. In the present work, we investigate the stability of nanoscale tips by means of computer simulations of surface diffusion processes on copper, the main material used in high-voltage electronics. We study the stability and lifetime of thin copper (Cu) surface nanotips at different temperatures in terms of diffusion processes. For this purpose we have developed a surface kinetic Monte Carlo (KMC) model where the jump processes are described by tabulated precalculated energy barriers. We show that tall surface features with high aspect ratios can be fairly stable at room temperature. However, the stability was found to depend strongly on the temperature: 13 nm nanotips with the major axes in the crystallographic directions were found to flatten down to half of the original height in less than 100 ns at temperatures close to the melting point, whereas no significant change in the height of these nanotips was observed after 10 {{μ }}{{s}} at room temperature. Moreover, the nanotips built up along the crystallographic directions were found to be significantly more stable than those oriented in the or crystallographic directions. The proposed KMC model has been found to be well-suited for simulating atomic surface processes and was validated against molecular dynamics simulation results via the comparison of the flattening times obtained by both methods. We also note that the KMC simulations were two orders of magnitude computationally faster than the corresponding molecular dynamics calculations.

  8. Unprecedented High Long Term Frequency Stability with a Macroscopic Resonator Oscillator

    CERN Document Server

    Grop, Serge; Bourgeois, Pierre-Yves; Bazin, Nicolas; Kersalé, Yann; Oxborrow, Mark; Rubiola, Enrico; Giordano, Vincent

    2010-01-01

    This article reports on the long-term frequency stabilty characterisation of a new type of cryogenic sapphire oscillator using an autonomous pulse-tube cryocooler as its cold source. This new design enables a relative frequency stability of better than 4.5e-15 over one day of integration. This represents to our knowledge the best long-term frequency stability ever obtained with a signal source based on a macroscopic resonator.

  9. Liquid Crystal Formation from Sunflower Oil: Long Term Stability Studies.

    Science.gov (United States)

    da Rocha-Filho, Pedro Alves; Maruno, Mônica; Ferrari, Márcio; Topan, José Fernando

    2016-06-09

    The Brazilian biodiversity offers a multiplicity of raw materials with great potential in cosmetics industry applications. Some vegetable oils and fatty esters increase skin hydration by occlusivity, keeping the skin hydrated and with a shiny appearance. Sunflower (Helianthus annus L.) oil is widely employed in cosmetic emulsions in the form of soaps, creams, moisturizers and skin cleansers due to the presence of polyphenols and its high vitamin E content. Liquid crystals are systems with many applications in both pharmaceutical and cosmetic formulations and are easily detected by microscopy under polarized light due to their birefringence properties. The aim of this research was to develop emulsions from natural sunflower oil for topical uses. Sunflower oil (75.0% w/w) was combined with liquid vaseline (25.0% w/w) employing a natural self-emulsifying base (SEB) derivative. The high temperature of the emulsification process did not influence the antioxidant properties of sunflower oil. Fatty esters were added to cosmetic formulations and extended stability tests were performed to characterize the emulsions. Fatty esters like cetyl palmitate and cetyl ester increase the formation of anisotropic structures. O/W emulsions showed acidic pH values and pseudoplastic behavior. The presence of a lamellar phase was observed after a period of 90 days under different storage conditions.

  10. Liquid Crystal Formation from Sunflower Oil: Long Term Stability Studies

    Directory of Open Access Journals (Sweden)

    Pedro Alves da Rocha-Filho

    2016-06-01

    Full Text Available The Brazilian biodiversity offers a multiplicity of raw materials with great potential in cosmetics industry applications. Some vegetable oils and fatty esters increase skin hydration by occlusivity, keeping the skin hydrated and with a shiny appearance. Sunflower (Helianthus annus L. oil is widely employed in cosmetic emulsions in the form of soaps, creams, moisturizers and skin cleansers due to the presence of polyphenols and its high vitamin E content. Liquid crystals are systems with many applications in both pharmaceutical and cosmetic formulations and are easily detected by microscopy under polarized light due to their birefringence properties. The aim of this research was to develop emulsions from natural sunflower oil for topical uses. Sunflower oil (75.0% w/w was combined with liquid vaseline (25.0% w/w employing a natural self-emulsifying base (SEB derivative. The high temperature of the emulsification process did not influence the antioxidant properties of sunflower oil. Fatty esters were added to cosmetic formulations and extended stability tests were performed to characterize the emulsions. Fatty esters like cetyl palmitate and cetyl ester increase the formation of anisotropic structures. O/W emulsions showed acidic pH values and pseudoplastic behavior. The presence of a lamellar phase was observed after a period of 90 days under different storage conditions.

  11. Combination and long term stability of the IGS Reprocessing campaign

    Science.gov (United States)

    Booker, David; Clarke, Peter J.; Lavallée, David A.

    2010-05-01

    During the relatively short life of the Global Positioning System (GPS) there have been several changes to the analysis procedure, leading to inhomogeneous coordinate time series. Although they have reduced systematic errors in more recent solutions, these changes have modified the apparent periodic signals observed and led to spurious discontinuities. The International GNSS Service (IGS) reprocessing campaign uses the latest operational models and techniques to reprocess the back catalogue of GPS data to produce remove inconsistencies caused by the various model changes, thus producing a homogeneous time series of station coordinates and Earth Rotation Parameters (ERPs). Weekly coordinate and ERP solutions from up to 11 reprocessing analysis centres (ACs) have been aligned to the ITRF and combined using the TANYA software in a rigorous weighted least-squares solution. Analysis of the time series of station coordinates and Helmert transformation parameters between the combined solution and the ITRF shows a at least a 50 percent improvement in the stability of the reprocessed weekly solutions compared with earlier operational products. There is a gradual decrease in the weighted root mean square coordinate difference, both between the combined weekly solutions and the ITRF and between the individual AC solutions and their weekly combination, which reaches a minimum around the end of 2005 with a slight increase thereafter. We observe clear differences in the periodicity of Helmert transformation parameters between the individual AC solutions and the combined solution, which presumably result from variations in AC processing strategy. There is a clear annual or near annual periodic variation in the scale difference between the combined solution and the ITRF05 and some less clear variation between the translation parameters, which needs further analysis as to its cause. Keywords: GPS, ITRF, IGS reprocessing campaign, periodic errors

  12. "Enzyme Test Bench," a high-throughput enzyme characterization technique including the long-term stability.

    Science.gov (United States)

    Rachinskiy, Kirill; Schultze, Hergen; Boy, Matthias; Bornscheuer, Uwe; Büchs, Jochen

    2009-06-01

    A new high throughput technique for enzyme characterization with specific attention to the long term stability, called "Enzyme Test Bench," is presented. The concept of the Enzyme Test Bench consists of short term enzyme tests in 96-well microtiter plates under partly extreme conditions to predict the enzyme long term stability under moderate conditions. The technique is based on the mathematical modeling of temperature dependent enzyme activation and deactivation. Adapting the temperature profiles in sequential experiments by optimal non-linear experimental design, the long term deactivation effects can be purposefully accelerated and detected within hours. During the experiment the enzyme activity is measured online to estimate the model parameters from the obtained data. Thus, the enzyme activity and long term stability can be calculated as a function of temperature. The engineered instrumentation provides for simultaneous automated assaying by fluorescent measurements, mixing and homogenous temperature control in the range of 10-85 +/- 0.5 degrees C. A universal fluorescent assay for online acquisition of ester hydrolysis reactions by pH-shift is developed and established. The developed instrumentation and assay are applied to characterize two esterases. The results of the characterization, carried out in microtiter plates applying short term experiments of hours, are in good agreement with the results of long term experiments at different temperatures in 1 L stirred tank reactors of a week. Thus, the new technique allows for both: the enzyme screening with regard to the long term stability and the choice of the optimal process temperature regarding such process parameters as turn over number, space time yield or optimal process duration. The comparison of the temperature dependent behavior of both characterized enzymes clearly demonstrates that the frequently applied estimation of long term stability at moderate temperatures by simple activity measurements

  13. Long-term frequency stabilization system for external cavity diode laser based on mode boundary detection.

    Science.gov (United States)

    Xu, Zhouxiang; Huang, Kaikai; Jiang, Yunfeng; Lu, Xuanhui

    2011-12-01

    We have realized a long-term frequency stabilization system for external cavity diode laser (ECDL) based on mode boundary detection method. In this system, the saturated absorption spectroscopy was used. The current and the grating of the ECDL were controlled by a computer-based feedback control system. By checking if there are mode boundaries in the spectrum, the control system determined how to adjust current to avoid mode hopping. This procedure was executed periodically to ensure the long-term stabilization of ECDL in the absence of mode hops. This diode laser system with non-antireflection coating had operated in the condition of long-term mode-hop-free stabilization for almost 400 h, which is a significant improvement of ECDL frequency stabilization system.

  14. Long-Term Performance of Chemically and Physically Modified Activated Carbons in Air Cathodes of Microbial Fuel Cells

    KAUST Repository

    Zhang, Xiaoyuan

    2014-07-31

    © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Activated carbon (AC) is a low-cost and effective catalyst for oxygen reduction in air cathodes of microbial fuel cells (MFCs), but its performance must be maintained over time. AC was modified by three methods: 1)pyrolysis with iron ethylenediaminetetraacetic acid (AC-Fe), 2)heat treatment (AC-heat), and 3)mixing with carbon black (AC-CB). The maximum power densities after one month with these AC cathodes were 35% higher with AC-Fe (1410±50mW m-2) and AC-heat (1400±20mW m-2), and 16% higher with AC-CB (1210±30mW m-2) than for plain AC (1040±20mW m-2), versus 1270±50mW m-2 for a Pt control. After 16months, the Pt cathodes produced only 250±10mW m-2. However, the AC-heat and AC-CB cathodes still produced 960-970mW m-2, whereas plain AC produced 860±60mW m-2. The performance of the AC cathodes was restored to >85% of the initial maximum power densities by cleaning with a weak acid solution. Based on cost considerations among the AC materials, AC-CB appears to be the best choice for long-term performance.

  15. Analysis of long-term performance and microbial community structure in bio-cathode microbial desalination cells.

    Science.gov (United States)

    Zhang, Huichao; Wen, Qinxue; An, Zhongyi; Chen, Zhiqiang; Nan, Jun

    2016-03-01

    A microbial desalination cell (MDC) could desalinate salt water without energy consumption and simultaneously generate bioenergy. Compared with an abiotic cathode MDC, an aerobic bio-cathode MDC is more sustainable and is less expensive to operate. In this study, the long-term operation (5500 h) performance of a bio-cathode MDC was investigated in which the power density, Coulombic efficiency, and salt removal rate were decreased by 71, 44, and 27 %, respectively. The primary reason for the system performance decrease was biofouling on the membranes, which increased internal resistance and reduced the ionic transfer and energy conversion efficiency. Changing membranes was an effective method to recover the MDC performance. The microbial community diversity in the MDC anode was low compared with that of the reported microbial fuel cell (MFC), while the abundance of Proteobacteria was 30 % higher. The content of Planctomycetes in the cathode biofilm sample was much higher than that in biofouling on the cation exchange membrane (CEM), indicating that Planctomycetes were relevant to cathode oxygen reduction.

  16. Treatment results and long-term stability of anterior open bite malocclusion.

    NARCIS (Netherlands)

    Remmers, D.; Hullenaar, RW Van't; Bronkhorst, E.M.; Berge, S.J.; Katsaros, C.

    2008-01-01

    OBJECTIVES: To evaluate treatment results and long-term stability of anterior open bite malocclusion and to identify predictive factors for both treatment results and their stability. DESIGN: Retrospective study. SETTING AND SAMPLE POPULATION: The Department of Orthodontics and Oral Biology at the R

  17. Long-term stability of PEG-based antifouling surfaces in seawater

    DEFF Research Database (Denmark)

    Noguer, Albert Camós; Olsen, Stefan Møller; Hvilsted, Søren

    2016-01-01

    Poly(ethylene glycol) (PEG) is a hydrophilic polymer that has been extensively used in the biomedical and marine environment due to its antifouling properties. In the biomedical field, PEG has been successfully used to functionalize surfaces due to its resistance to cell and nonspecific protein...... adsorption. However, the long-term stability of PEG has limited its use in some areas. In the shipping industry, there is a great need for long-term solutions to keep the hulls of the ships fouling-free. The long-term stability of PEG in polydimethylsiloxane (PDMS) fouling-release coatings is studied here....... The influence of the chemistry of the PEG compounds, the chosen laboratory degrading agents, and the possible degradation pathways and products are discussed....

  18. Ni/YSZ microstructure optimization for long-term stability of solid oxide electrolysis cells

    DEFF Research Database (Denmark)

    Hauch, Anne; Brodersen, Karen; Karas, Filip;

    2014-01-01

    In the last decade there has been a renewed and increased interest in electrolysis using solid oxide cells (SOC). So far the vast majority of results reported on long-term durability of solid oxide electrolysis cells (SOEC) have been obtained using SOC produced and optimized for fuel cell operation......; i.e. solid oxide fuel cells (SOFC). However, previous long-term tests have shown that the stability behavior of the Ni/yttria-stabilized-zirconia (Ni/YSZ) fuel electrode may fall out quite differently depending on whether the cell is operated in fuel cell or electrolysis mode at otherwise similar...... test conditions. Initial work has shown significant microstructural changes of the Ni/YSZ electrode close to the electrolyte interface after long-term steam electrolysis test at -1 A/cm2 at 800 C. The results indicate that it will be advantageous to optimize the electrode structure with the aim...

  19. Statistical analysis for long-term stability studies with multiple storage conditions

    NARCIS (Netherlands)

    van den Heuvel, Edwin R.; Almalik, Osama; Nijhuis, Michiel B.; Warner, Edward I.

    2011-01-01

    To determine the shelf life of new medicinal products, long-term stability studies are conducted of at least three registration batches at multiple storage conditions. It is common practice to perform a statistical analysis on the resulting data separately for each storage condition. Although this i

  20. Development and Long-Term Stability of a Novel Microbial Fuel Cell BOD Sensor with MnO2 Catalyst

    Science.gov (United States)

    Kharkwal, Shailesh; Tan, Yi Chao; Lu, Min; Ng, How Yong

    2017-01-01

    A novel microbial fuel cell (MFC)-based biosensor was designed for continuous monitoring of biochemical oxygen demand (BOD) in real wastewater. To lower the material cost, manganese dioxide (MnO2) was tested as an innovative cathode catalyst for oxygen reduction in a single chamber air-cathode MFC, and two different crystalline structures obtained during synthesis of MnO2 (namely β- and γ-MnO2) were compared. The BOD sensor was studied in a comprehensive way, using both sodium acetate solution and real domestic wastewater (DWW). The optimal performance of the sensor was obtained with a β-MnO2 catalyst, with R2 values of 0.99 and 0.98 using sodium acetate solution and DWW, respectively. The BOD values predicted by the β-MnO2 biosensor for DWW were in agreement with the BOD5 values, determined according to standard methods, with slight variations in the range from 3% to 12%. Finally, the long-term stability of the BOD biosensor was evaluated over 1.5 years. To the best of our knowledge, this is the first report of an MFC BOD sensor using an MnO2 catalyst at the cathode; the feasibility of using a low-cost catalyst in an MFC for online measurement of BOD in real wastewater broadens the scope of applications for such devices. PMID:28134838

  1. Development and Long-Term Stability of a Novel Microbial Fuel Cell BOD Sensor with MnO₂ Catalyst.

    Science.gov (United States)

    Kharkwal, Shailesh; Tan, Yi Chao; Lu, Min; Ng, How Yong

    2017-01-28

    A novel microbial fuel cell (MFC)-based biosensor was designed for continuous monitoring of biochemical oxygen demand (BOD) in real wastewater. To lower the material cost, manganese dioxide (MnO₂) was tested as an innovative cathode catalyst for oxygen reduction in a single chamber air-cathode MFC, and two different crystalline structures obtained during synthesis of MnO₂ (namely β- and γ-MnO₂) were compared. The BOD sensor was studied in a comprehensive way, using both sodium acetate solution and real domestic wastewater (DWW). The optimal performance of the sensor was obtained with a β-MnO₂ catalyst, with R² values of 0.99 and 0.98 using sodium acetate solution and DWW, respectively. The BOD values predicted by the β-MnO₂ biosensor for DWW were in agreement with the BOD₅ values, determined according to standard methods, with slight variations in the range from 3% to 12%. Finally, the long-term stability of the BOD biosensor was evaluated over 1.5 years. To the best of our knowledge, this is the first report of an MFC BOD sensor using an MnO₂ catalyst at the cathode; the feasibility of using a low-cost catalyst in an MFC for online measurement of BOD in real wastewater broadens the scope of applications for such devices.

  2. Improvement of the long term stability in the high temperature solid oxide fuel cell using functional layers

    Energy Technology Data Exchange (ETDEWEB)

    Brueckner, B.; Guenther, C.; Ruckdaeschel, R. [Siemens AG, Erlangen (Germany)] [and others

    1996-12-31

    In the planar Siemens design of the solid oxide fuel cell a metallic interconnector is used to seperate the ceramic single cells. A disadvantage of the metallic bipolar plate which consists of a chromium alloy is the formation of high volatile Cr-oxides and hydroxides at the surface at the cathode side. The reaction products evaporate and are reduced at the cathode/electrolyte interface to form new crystalline phases. This process gives rise to long term cell degradation. Protective coatings might be successful in preventing the chromium oxide evaporation. The required properties of the protective layers are (I) high electrical conductivity, (II) similar coefficients of thermal expansion to the bipolar plate (III), chemical compatibility to the bipolar plate and cathode material, (IV) a low diffusion coefficient of Cr and (V) chemical stability up to 1223K under oxygen atmosphere. Furthermore, during operation at 1223K an electrical contact between the metallic plate and the electrodes has to be maintained. This problem could be solved using ceramic layer between the metallic plate and the single cells.

  3. Long-term orbital stability of exosolar planetary systems with highly eccentric orbits

    Science.gov (United States)

    Antoniadou, Kyriaki I.; Voyatzis, George

    2016-10-01

    Nowadays, many extrasolar planetary systems possessing at least one planet on a highly eccentric orbit have been discovered. In this work, we study the possible long-term stability of such systems. We consider the general three body problem as our model. Highly eccentric orbits are out of the Hill stability regions. However, mean motion resonances can provide phase protection and orbits with long-term stability exist. We construct maps of dynamical stability based on the computation of chaotic indicators and we figure out regions in phase space, where the long-term stability is guaranteed. We focus on regions where at least one planet is highly eccentric and attempt to associate them with the existence of stable periodic orbits. The values of the orbital elements, which are derived from observational data, are often given with very large deviations. Generally, phase space regions of high eccentricities are narrow and thus, our dynamical analysis may restrict considerably the valid domain of the system's location.

  4. Long-term orbital stability of exosolar planetary systems with highly eccentric orbits

    CERN Document Server

    Antoniadou, Kyriaki I

    2016-01-01

    Nowadays, many extrasolar planetary systems possessing at least one planet on a highly eccentric orbit have been discovered. In this work, we study the possible long-term stability of such systems. We consider the general three body problem as our model. Highly eccentric orbits are out of the Hill stability regions. However, mean motion resonances can provide phase protection and orbits with long-term stability exist. We construct maps of dynamical stability based on the computation of chaotic indicators and we figure out regions in phase space, where the long-term stability is guaranteed. We focus on regions where at least one planet is highly eccentric and attempt to associate them with the existence of stable periodic orbits. The values of the orbital elements, which are derived from observational data, are often given with very large deviations. Generally, phase space regions of high eccentricities are narrow and thus, our dynamical analysis may restrict considerably the valid domain of the system's locat...

  5. Long-term diagnostic stability and outcome in recent first-episode cohort studies of schizophrenia.

    Science.gov (United States)

    Bromet, Evelyn J; Naz, Bushra; Fochtmann, Laura J; Carlson, Gabrielle A; Tanenberg-Karant, Marsha

    2005-07-01

    Knowing the long-term outcomes of schizophrenia and stability of a schizophrenia diagnosis are important from a clinical standpoint as well as essential to future research on diagnostic classifications and outcome. As in prior research on schizophrenia, prospectively designed long-term studies over the past 30 years find that the predominant course of illness includes chronically poor functioning, with little evidence of long-term improvement. Mortality due to suicide is significant at about 10% over 10-year periods of follow-up. Within studies, outcome domains are interrelated, and the relatively consistent predictors of poorer outcome include family history of schizophrenia, insidious onset, poor premorbid functioning, severity of negative symptoms, and severity and duration of untreated psychosis. Residing in a developed rather than a developing country is also associated with a poorer long-term course. The diagnostic stability of schizophrenia is less well studied. The positive predictive value exceeds 90%, and preliminary findings from the 10-year follow-up of the Suffolk County Mental Health Project cohort have found that the agreement across time increased from k = .52 (baseline to 10 years) to k = .76 (6 or 24 months to 10 years). After discussing several limitations of the existing body of research, we suggest that future studies incorporate more "modifiable" risk factors into the assessment battery that could potentially be used as building blocks in experimental intervention designs.

  6. Long-term stability investigation of o/w cosmetic creams stabilized by mixed emulsifier

    Directory of Open Access Journals (Sweden)

    Đekić Ljiljana M.

    2012-01-01

    Full Text Available Polyglyceryl-3 Methylglucose Distearate (PMD, TEGO® Care 450, Evonik, Germanyis natural (vegetable, non-ionic, PEG-free emulsifier, suitable for the formulation of oil-in-water (o/w cosmetic creams and lotions. The oil phase components can be selected from mineral oils, vegetable oils and synthetic esters, which enable different variety of application profile of these emulsions. It is possible to prepare stable emulsions using low-level concentration of the PMD (2-3% if lotions contain 10-25%, and creams 20-40 % of oil phase. PMD forms liquid crystal structure in the presence of stearic acid, glyceryl stearate, fatty alcohols, or their combinations. The o/w type creams, stabilized by these mixed emulsifiers are complex, multiphase systems. The aim of this work was to formulate, prepare and investigate long-term stability of the o/w creams stabilized by mixed emulsifier polyglyceryl-3 methylglucose distearate/glyceryl stearate/stearyl alcohol, depending on concentration levels of PMD (2% or 3% and oil:water phase ratio (20:80 and 30:70. The samples were prepared using hot/hot procedure. Organoleptic inspection, centrifugation test, rheological measurements, electric conductivity and pH value measurements were performed 72 h, 1, 3, 12 and 30 months after preparation. The prepared samples were apparently white and homogenous creams. The consistency and homogeneity were preserved after centrifugation of the creams after 72 h, 1, 3, 12 and 30 months storage, and no phase separation could be detected. The pH values obtained are suitable for skin application. Conductivity values (25.2-63.7 μS cm1, 72 h after preparation were attributed to the multiple phase o/w emulsions with high percentages of fixed water. Results of the rheological measurements have shown that the investigated creams exhibited non-Newtonian thyxotropic behavior. The concentration of emulsifier PMD and oil phase content had an influence on the rheological parameters of investigated

  7. Long term stability analysis of cast iron shaft linings after Coal Mine closure and flooding

    Energy Technology Data Exchange (ETDEWEB)

    Hadj-Hassen, F. [Ecole des Mines de Paris - CGES, 77 - Fontainebleau (France); Bienvenu, Y. [Ecole des Mines de Paris, CM, 91 - Evry (France); Noirel, J.F. [Charbonnages de France, DTN, 57 - Freyming Merlebach (France); Metz, M. [charbonnages de France, ESA, 57 - Freyming Merlebach (France)

    2005-07-01

    This paper presents the results of a study conducted to analyse the long term stability of the cast iron shaft lining after coal mine closure and flooding. The attention is mainly focused on the behaviour during the critical phase of flooding as well as the phase corresponding to the disappearance of the water pressure and the stabilization of the environment. This pluri-disciplinary study was conducted by a team combining specialists in rock mechanics who identified the main risks and the conditions of stability of the lining and specialists in metallurgy who studied the composition of the cast iron and its corrosion behaviour after exposure to mine water. (authors)

  8. Note: Improving long-term stability of hot-wire anemometer sensors by means of annealing.

    Science.gov (United States)

    Lundström, H

    2015-08-01

    Annealing procedures for hot-wire sensors of platinum and platinum-plated tungsten have been investigated experimentally. It was discovered that the two investigated sensor metals behave quite differently during the annealing process, but for both types annealing may improve long-term stability considerably. Measured drift of sensors both without and with prior annealing is presented. Suggestions for suitable annealing temperatures and times are given.

  9. Note: Improving long-term stability of hot-wire anemometer sensors by means of annealing

    Energy Technology Data Exchange (ETDEWEB)

    Lundström, H., E-mail: hans.lundstrom@hig.se [Department of Building, Energy and Environmental Engineering, University of Gävle, SE-801 76 Gävle (Sweden)

    2015-08-15

    Annealing procedures for hot-wire sensors of platinum and platinum-plated tungsten have been investigated experimentally. It was discovered that the two investigated sensor metals behave quite differently during the annealing process, but for both types annealing may improve long-term stability considerably. Measured drift of sensors both without and with prior annealing is presented. Suggestions for suitable annealing temperatures and times are given.

  10. Note: Improving long-term stability of hot-wire anemometer sensors by means of annealing

    Science.gov (United States)

    Lundström, H.

    2015-08-01

    Annealing procedures for hot-wire sensors of platinum and platinum-plated tungsten have been investigated experimentally. It was discovered that the two investigated sensor metals behave quite differently during the annealing process, but for both types annealing may improve long-term stability considerably. Measured drift of sensors both without and with prior annealing is presented. Suggestions for suitable annealing temperatures and times are given.

  11. Long-term stability of contour augmentation in the esthetic zone

    DEFF Research Database (Denmark)

    Jensen, Simon S; Bosshardt, Dieter D; Gruber, Reinhard

    2014-01-01

    BACKGROUND: Contour augmentation around early-placed implants (Type 2 placement) using autogenous bone chips combined with deproteinized bovine bone mineral (DBBM) and a collagen barrier membrane has been documented to predictably provide esthetically satisfactory clinical outcomes. In addition...... study confirms previous findings that osseointegrated DBBM particles do not tend to undergo substitution over time. This low substitution rate may be the reason behind the clinically and radiographically documented long-term stability of contour augmentation using a combination of autogenous bone chips...

  12. Superior long-term stability of a glucose biosensor based on inserted barrel plating gold electrodes.

    Science.gov (United States)

    Hsu, Cheng-Teng; Hsiao, Hung-Chan; Fang, Mei-Yen; Zen, Jyh-Myng

    2009-10-15

    Disposable one shot usage blood glucose strips are routinely used in the diagnosis and management of diabetes mellitus and their performance can vary greatly. In this paper we critically evaluated the long-term stability of glucose strips made of barrel plating gold electrodes. Compared to other glucose biosensing platforms of vapor deposited palladium and screen printed carbon electrodes, the proposed glucose biosensor was found to show the best stability among the three biosensing platforms in thermal acceleration experiments at 40 degrees C for 6 months with an average bias of 3.4% at glucose concentrations of 5-20 mM. The precision test of this barrel plating gold glucose biosensor also showed the best performance (coefficients of variation in the range of 1.4-2.4%) in thermal acceleration experiments at 40 degrees C, 50 degrees C and 70 degrees C for 27 days. Error grid analysis revealed that all measurements fell in zone A and zone B. Regression analysis showed no significant difference between the proposed biosensor and the reference method at 99% confidence level. The amperometric glucose biosensor fabricated by inserting two barrel plating gold electrodes onto an injection-molding plastic base followed by immobilizing with a bio-reagent layer and membrane was very impressive with a long-term stability up to 2.5 years at 25 degrees C. Overall, these results indicated that the glucose oxidase/barrel plating gold biosensing platform is ideal for long-term accurate glycemic control.

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

    Science.gov (United States)

    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.

  14. Long-term stabilization of organic solar cells using hydroperoxide decomposers as additives

    Science.gov (United States)

    Turkovic, Vida; Engmann, Sebastian; Tsierkezos, Nikos; Hoppe, Harald; Madsen, Morten; Rubahn, Horst-Günter; Ritter, Uwe; Gobsch, Gerhard

    2016-03-01

    Stability of organic solar cells (OPV) remains a big problem on the way to their commercialization. Different approaches are being investigated: development of intrinsically more photochemically stable materials, optimization of encapsulation, and implementation of getter and UV blocking layers. In this study, we investigate stabilization of OPV devices using hydroperoxide decomposers as stabilizing additives. A set of five commercially available additives of organophosphorus, organosulfur, Ni chelate, and blocked thiol type are compared, ternary blended into the active layer, under exposure to aging under ISOS-3 degradation conditions. Improvements in long-term performance of OPV devices were observed upon stabilization with Advapak NEO-1120, lifetime was prolonged by a factor of 1.7, and accumulated power generation increased by a factor of 1.4. The stabilizing mechanisms are discussed using spectroscopic and microscopic measurements.

  15. Rheological Characteristics of Weak Rock Mass and Effects on the Long-Term Stability of Slopes

    Science.gov (United States)

    Yang, Tianhong; Xu, Tao; Liu, Hongyuan; Zhang, Chunming; Wang, Shanyong; Rui, Yongqin; Shen, Li

    2014-11-01

    The creep deformation behavior of the northern slope of an open-pit mine is introduced. Direct shear creep tests are then conducted for the samples taken from the northern slope to study the rheological characteristics of the rock mass. The experimental results are analyzed afterwards using an empirical method to develop a rheological model for the rock mass. The proposed rheological model is finally applied to understand the creep behavior of the northern slope, predict the long-term stability, and guide appropriate measures to be taken at suitable times to increase the factor of safety to ensure stability. Through this study, a failure criterion is proposed to predict the long-term stability of the slope based on the rheological characteristics of the rock mass and a critical deformation rate is adopted to determine when appropriate measures should be taken to ensure slope stability. The method has been successfully applied for stability analysis and engineering management of the toppling and slippage of the northern slope of the open-pit mine. This success in application indicates that it is theoretically accurate, practically feasible, and highly cost-effective.

  16. Long-term actuarial survivorship analysis of an interspinous stabilization system.

    Science.gov (United States)

    Sénégas, Jacques; Vital, Jean-Marc; Pointillart, Vincent; Mangione, Paolo

    2007-08-01

    In 1986, an interspinous dynamic stabilization system (the prototype of the current Wallis implant) was designed to stiffen unstable operated degenerate lumbar segments with a hard interspinous blocker to limit extension and a tension band around the spinous processes to secure the implant and limit flexion. Restoring physiological mechanical conditions to the treated level(s) while preserving some intervertebral mobility was intended to treat low-back pain related to degenerative instability without increasing stress forces in the adjacent segments. The procedure was easily reversible. If low back pain persisted or recurred, the device was removed and stability was achieved using fusion. The intermediate-term results were promising, but the long-term safety and efficacy of this dynamic interspinous stabilization device has not been previously documented. We retrospectively reviewed the hospital files of all the patients (n = 241) who had this dynamic stabilization system implanted between 1987 and 1995, contacting as many as possible to determine the actuarial survivorship of the system. In this manner, 142 of the 241 patients (58.9%) were contacted by telephone. The endpoints used for the survivorship analysis were 'any subsequent lumbar operation' and 'implant removal'. At 14 years follow-up, values of actuarial survivorship with 95% confidence interval were 75.9 +/- 8.3 and 81.3 +/- 6.8% for the endpoints 'any subsequent lumbar operation' and 'implant removal', respectively. There was no difference in survivorship of multiple-level implants with respect to single-level devices. Although the conclusions of the present study must be tempered by the 41% attrition rate, these findings support the long-term safety of this system, and possibly long-term protective action against adjacent-level degeneration by motion preservation. Outcomes at least equivalent to those of fusion were observed without the primary drawbacks of fusion.

  17. Long-term stabilization of the optical fiber phase control using dual PID

    Institute of Scientific and Technical Information of China (English)

    WU; Yue; CHEN; Guozhu; SHEN; Yong; ZOU; Hongxin

    2015-01-01

    We propose an approach of long-term stabilization of optical fiber phase by controlling a piezo-based phase modulator and a Peltier component attached to the fiber via a phase-locked loop( PLL) circuit w ith dual proportional-integral- derivative( PID) adjustment. With this approach,we can suppress the fast disturbance and slow drifting of optical fiber to satisfy the requirements of optical phase long-term locking. In theory,a mathematical model of an optical fiber phase control system is established. The disturbance term induced by environment influence is considered into the PLL model. The monotonous and continuous changing environment disturbance w ill cause a steady-state error in this theory model. The experimental results accords w ell w ith the theory. The steady-state performance,adjusting time,and overshoot can be improved by using the dual PID control. As a result,the long-term,highly stable and low noise fiber phase locking is realized experimentally.

  18. Long-term stability analysis of the left bank abutment slope at Jinping I hydropower station

    Institute of Scientific and Technical Information of China (English)

    Long Zhang; Qiang Yang; Yaoru Liu

    2016-01-01

    The time-dependent behavior of the left bank abutment slope at Jinping I hydropower station has a major influence on the normal operation and long-term safety of the hydropower station. To solve this problem, a geomechanical model containing various faults and weak structural planes is established, and numerical simulation is conducted under normal water load condition using FLAC3D, incorporating creep model proposed based on thermodynamics with internal state variables theory. The creep deformations of the left bank abutment slope are obtained, and the changes of principal stresses and deformations of the dam body are analyzed. The long-term stability of the left bank abutment slope is evaluated ac-cording to the integral curves of energy dissipation rate in domain and its derivative with respect to time, and the non-equilibrium evolution rules and the characteristic time can also be determined using these curves. Numerical results show that the left bank abutment slope tends to be stable in a global sense, and the stress concentration is released. It is also indicated that more attention should be paid to some weak regions within the slope in the long-term deformation process.

  19. Long-Term Stability of Residual Stress Improvement by Water Jet Peening Considering Working Processes.

    Science.gov (United States)

    Hashimoto, Tadafumi; Osawa, Yusuke; Itoh, Shinsuke; Mochizuki, Masahito; Nishimoto, Kazutoshi

    2013-06-01

    To prevent primary water stress corrosion cracking (PWSCC), water jet peening (WJP) has been used on the welds of Ni-based alloys in pressurized water reactors (PWRs). Before WJP, the welds are machined and buffed in order to conduct a penetrant test (PT) to verify the weld qualities to access, and microstructure evolution takes place in the target area due to the severe plastic deformation. The compressive residual stresses induced by WJP might be unstable under elevated temperatures because of the high dislocation density in the compressive stress layer. Therefore, the stability of the compressive residual stresses caused by WJP was investigated during long-term operation by considering the microstructure evolution due to the working processes. The following conclusions were made: The compressive residual stresses were slightly relaxed in the surface layers of the thermally aged specimens. There were no differences in the magnitude of the relaxation based on temperature or time. The compressive residual stresses induced by WJP were confirmed to remain stable under elevated temperatures. The stress relaxation at the surface followed the Johnson-Mehl equation, which states that stress relaxation can occur due to the recovery of severe plastic strain, since the estimated activation energy agrees very well with the self-diffusion energy for Ni. By utilizing the additivity rule, it was indicated that stress relaxation due to recovery is completed during the startup process. It was proposed that the long-term stability of WJP under elevated temperatures must be assessed based on compressive stresses with respect to the yield stress. Thermal elastic-plastic creep analysis was performed to predict the effect of creep strain. After 100 yr of simulated continuous operation at 80% capacity, there was little change in the WJP compressive stresses under an actual operating temperature of 623 K. Therefore, the long-term stability of WJP during actual operation was

  20. Long-term stability of fibre-optic transmission for multi-object spectroscopy

    CERN Document Server

    Sharp, R; Cannon, R D

    2012-01-01

    We present an analysis of the long-term stability of fibre-optic transmission properties for fibre optics in astronomy. Data from six years of operation of the AAOmega multi-object spectrograph at the Anglo-Australian Telescope is presented. We find no evidence for significant degradation in the bulk transmission properties of the 38 m optical fibre train. Significant losses (<20% relative, 4% absolute) are identified and associated with the end termination of the optical fibres in the focal plane. Improved monitoring and maintenance can rectify the majority of this performance degradation.

  1. The nekhoroshev theorem and long-term stabilities in the solar system

    Directory of Open Access Journals (Sweden)

    Guzzo M.

    2015-01-01

    Full Text Available The Nekhoroshev theorem has been often indicated in the last decades as the reference theorem for explaining the dynamics of several systems which are stable in the long-term. The Solar System dynamics provides a wide range of possible and useful applications. In fact, despite the complicated models which are used to numerically integrate realistic Solar System dynamics as accurately as possible, when the integrated solutions are chaotic the reliability of the numerical integrations is limited, and a theoretical long-term stability analysis is required. After the first formulation of Nekhoroshev’s theorem in 1977, many theoretical improvements have been achieved. On the one hand, alternative proofs of the theorem itself led to consistent improvements of the stability estimates; on the other hand, the extensions which were necessary to apply the theorem to the systems of interest for Solar System Dynamics, in particular concerning the removal of degeneracies and the implementation of computer assisted proofs, have been developed. In this review paper we discuss some of the motivations and the results which have made Nekhoroshev’s theorem a reference stability result for many applications in the Solar System dynamics.

  2. Long-term stability of self-assembled monolayers on 316L stainless steel.

    Science.gov (United States)

    Kaufmann, C R; Mani, G; Marton, D; Johnson, D M; Agrawal, C M

    2010-04-01

    316L stainless steel (316L SS) has been extensively used for making orthopedic, dental and cardiovascular implants. The use of phosphonic acid self-assembled monolayers (SAMs) on 316L SS has been previously explored for potential biomedical applications. In this study, we have investigated the long-term stability of methyl (-CH(3)) and carboxylic acid (-COOH)-terminated phosphonic acid SAMs on 316L under physiological conditions. The stability of SAMs on mechanically polished and electropolished 316L SS was also investigated as a part of this study. Well-ordered and uniform -CH(3)- and -COOH-terminated SAMs were coated on mechanically polished and electropolished 316L SS surfaces. The long-term stability of SAMs on 316L SS was investigated for up to 28 days in Tris-buffered saline (TBS) at 37 degrees C using x-ray photoelectron spectroscopy, atomic force microscopy and contact angle goniometry. A significant amount of phosphonic acid molecules was desorbed from the 316L SS surfaces within 1 to 7 days of TBS immersion followed by a slow desorption of molecules over the remaining days. The -COOH-terminated SAM was found to be more stable than the -CH(3)-terminated SAM on both mechanically and electropolished surfaces. No significant differences in the desorption behavior of SAMs were observed between mechanically and electropolished 316L SS surfaces.

  3. Film Grain-Size Related Long-Term Stability of Inverted Perovskite Solar Cells.

    Science.gov (United States)

    Chiang, Chien-Hung; Wu, Chun-Guey

    2016-09-22

    The power conversion efficiency (PCE) of the perovskite solar cell is high enough to be commercially viable. The next important issue is the stability of the device. This article discusses the effect of the perovskite grain-size on the long-term stability of inverted perovskite solar cells. Perovskite films composed of various sizes of grains were prepared by controlling the solvent annealing time. The grain-size related stability of the inverted cells was investigated both in ambient atmosphere at relative humidity of approximately 30-40 % and in a nitrogen filled glove box (H2 Osolar cell based on a perovskite film having the grain size larger than 1 μm (D-10) decreases less than 10 % with storage in a glove box and less than 15 % when it was stored under an ambient atmosphere for 30 days. However, the cell using the perovskite film composed of small (∼100 nm) perovskite grains (D-0) exhibits complete loss of PCE after storage under the ambient atmosphere for only 15 days and a PCE loss of up to 70 % with storage in the glove box for 30 days. These results suggest that, even under H2 O-free conditions, the chemical- and thermal-induced production of pin holes at the grain boundaries of the perovskite film could be the reason for long-term instability of inverted perovskite solar cells.

  4. Application of rheology for assessment and prediction of the long-term physical stability of emulsions.

    Science.gov (United States)

    Tadros, Tharwat

    2004-05-20

    This review deals with the use of rheology for assessment and prediction of the long-term physical stability of emulsions. It starts with an introduction, highlighting the importance of having accelerated test to predict emulsion stability. This is followed by a section on the stability/instability of emulsion systems, giving a brief summary of the driving force of each instability process and its prevention. The classical techniques that can be applied for assessment of creaming or sedimentation, flocculation, Ostwald ripening, coalescence and phase inversion are briefly described. This is followed by several sections on the application of rheological techniques to assess and predict each of these instabilities. This involves the use of steady state shear stress-shear rate measurements, constant stress (creep) measurements and dynamic (oscillatory) techniques. The last section gives an example of model emulsions to illustrate the correlation between the various break-down processes with the rheological characteristics of the system.

  5. Structural evolution and the capacity fade mechanism upon long-term cycling in Li-rich cathode material.

    Science.gov (United States)

    Song, Bohang; Liu, Zongwen; Lai, Man On; Lu, Li

    2012-10-01

    High capacity Li-rich layered cathode Li(Li(0.2)Mn(0.54)Ni(0.13)Co(0.13))O(2) and doped one are investigated to understand mechanisms of capacity fade as well as voltage decrease upon long-term cycling. Detailed electrochemical analysis reveals a phase-separation-like behavior with increase in the cycle number, which is responsible for gradual reduction in discharge voltage. X-ray photoelectron spectroscopy (XPS), transmission electron microscope coupled with energy dispersive X-ray spectroscopy (TEM-EDS) and inductively coupled plasma emission spectrometry (ICP) analysis results show increase in valence of transition metals on the surface of powder at a fully discharged state in addition to surface dissolution of Ni, leading to rapid capacity loss. High resolution transmission electron microscopy (HR-TEM) shows a phase transformation from original layered structure into spinel-like nano-domains in local structure. Though such an unexpected structural change is unfavorable because of lower output voltage, it is observed to be beneficial for high-rate performance.

  6. Long-term manure amendment increases organic C storage and stabilization in Loess soil

    Science.gov (United States)

    Liang, B.; Zhao, W.; Yang, X.; Zhou, J.

    2011-12-01

    Soil is the largest terrestrial pool for organic carbon in the biosphere. Therefore, sequestration of C in soils is often seen as a 'win-win' proposition. The long-term combined application of manure with chemical fertilizers had increased the accumulation of organic carbon in soil (SOC); and the results from the application of chemical fertilizers on the stock of SOC in soil were inconsistent. Furthermore, less studies have been conducted to evaluate the effect of different fertilization, especially the application of N fertilizer, on the stabilization of SOC in the different fertilized soils. In this study, we hypothesized that the long-term different fertilization not only affect organic C storage, but also its stabilization in soil. Therefore, we conducted an incubation experiment with the soils from a long-term fertilization trials. Soil samples were collected from the three fertilized plots, ((1) no fertilizer, NF soil, (2) inorganic NPK fertilizers, NPK soil; and (3) Manure + NPK fertilizers, MNPK soil) of a long-term fertilization experiment initiated in 1990 in Shaanxi, China. The soils were incubated at 28o C for 30 days with the different treatments, i.e., (1) control with no addition (CK), (2) added 200 mg N kg-1 soil (+ NH4-N), (3) added 1000 mg C kg-1 soil (+ glucose), and (4) added 200 mg N kg-1 soil + 1000 mg C kg-1 soil (+glucose + NH4-N). The evolved CO2 was determined by titration of the excess NaOH with 0.1 M HCl. Decomposition of SOC in the different soils was evaluate with the accumulation of released CO2-C based on dry soil (in mg C kg-1 soil), and the decomposition rate of SOC during the incubation (in % of total organic C in soil). Long-term different fertilization treatments (NPK, and MNPK soil) significantly increased the organic C storage in 0-100 cm soil profile. SOC storage in MNPK soil (83.0 t ha-1) was significantly higher than NPK soil (80.8 t ha-1), and both were significantly higher than the no fertilizer soil. The decomposition

  7. State-of-the-art MCT IR-modules with enhanced long term and cycle stability

    Science.gov (United States)

    Breiter, R.; Wendler, J.; Lutz, H.; Rutzinger, S.; Schallenberg, T.; Ziegler, J.; Rühlich, I.

    2012-06-01

    Current trends on the enhancement of MCT FPA IR-modules are reduction of size, weight and power (SWaP), increase of resolution with large detector arrays, provision of staring LWIR or dual-band capability. This is achieved by reduction of pixel size, higher operating temperatures (HOT) or complex pixel structures together with the optimization of dewars, adapted cooling engines and proximity electronics. To meet these demands AIM is working on MCT single-band MWIR or LWIR modules with formats 640x512 or 1280x1024 in 15μm pitch and a dual-band MWIR/LWIR module 640x512 in 20μm pitch. As a first step high operating temperatures for MWIR 120K and LWIR 80K were demonstrated, development for MWIR >= 150K and LWIR >= 90K is ongoing. The modules are realized as integrated detector cooler assemblies (IDCA) with proximity electronics. The 640x512/15μm pitch modules are already available in application specific configurations e.g. having integral rotary or split linear cooling engines. Besides implementation of the above mentioned capabilities also improvement in long term and cycle stability of IRmodules has been achieved which is important to fully benefit from increased mission times and longer maintenance periods by HOT. Especially staring MCT LWIR modules so far required sophisticated non-uniformity correction (NUC) processing to provide acceptable long term image quality while former scanning systems usually used implemented temperature references for NUC update. For a thermal imager setup with the LWIR 640x512/15μm module two-point correction with factory calibrated gain coefficients together with a new offset calibration after every cool down cycle is used. The paper will present the results of AIM's current staring single-band MCT IR-modules in MWIR or LWIR configuration especially regarding to their long term and cycle stability.

  8. Long-term stability and temperature variability of Iris AO segmented MEMS deformable mirrors

    Science.gov (United States)

    Helmbrecht, M. A.; He, M.; Kempf, C. J.; Marchis, F.

    2016-07-01

    Long-term stability of deformable mirrors (DM) is a critical performance requirement for instruments requiring open-loop corrections. The effects of temperature changes in the DM performance are equally critical for such instruments. This paper investigates the long-term stability of three different Iris AO PTT111 DMs that were calibrated at different times ranging from 13 months to nearly 29 months prior to subsequent testing. Performance testing showed that only a small increase in positioning errors occurred from the initial calibration date to the test dates. The increases in errors ranged from as little as 1.38 nm rms after 18 months to 5.68 nm rms after 29 months. The paper also studies the effects of small temperature changes, up to 6.2°C around room temperature. For three different arrays, the errors ranged from 0.62-1.42 nm rms/°C. Removing the effects of packaging shows that errors are heated.

  9. Reflective point-diffraction microscopic interferometer with long-term stability (Invited Paper)

    Institute of Scientific and Technical Information of China (English)

    Rongli Guo; Baoli Yao; Peng Gao; Junwei Min; Juanjuan Zheng; Tong Ye

    2011-01-01

    An on-axis phase-shifting reflective point-diffraction microscopic interferometer for quantitative phase microscopy based on Michelson architecture is proposed.A cube beamsplitter splits the object wave spectrum into two copies within two arms.Reference wave is rebuilt in one arm by low-pass filtering on the object wave frequency spectrum with a pinhole-mask mirror,and interferes with the object wave from the other arm.Polarization phase-shifting is performed and phase imaging on microscale specimens is implemented.The experimental results demonstrate that the proposed scheme has the advantage of long-term stability due to its quasi common-path geometry with full use of laser energv.%An on-axis phase-shifting reflective point-diffraction microscopic interferometer for quantitative phase microscopy based on Michelson architecture is proposed. A cube beamsplitter splits the object wave spectrum into two copies within two arms. Reference wave is rebuilt in one arm by low-pass filtering on the object wave frequency spectrum with a pinhole-mask mirror, and interferes with the object wave from the other arm. Polarization phase-shifting is performed and phase imaging on microscale specimens is implemented. The experimental results demonstrate that the proposed scheme has the advantage of long-term stability due to its quasi common-path geometry with full use of laser energy.

  10. Long-term stability and temperature variability of Iris AO segmented MEMS deformable mirrors

    CERN Document Server

    Helmbrecht, M A; Kempf, C J; Marchis, F

    2016-01-01

    Long-term stability of deformable mirrors (DM) is a critical performance requirement for instruments requiring open-loop corrections. The effects of temperature changes in the DM performance are equally critical for such instruments. This paper investigates the long-term stability of three different Iris AO PTT111 DMs that were calibrated at different times ranging from 13 months to nearly 29 months prior to subsequent testing. Performance testing showed that only a small increase in positioning errors occurred from the initial calibration date to the test dates. The increases in errors ranged from as little as 1.38 nm rms after 18 months to 5.68 nm rms after 29 months. The paper also studies the effects of small temperature changes, up to 6.2{\\deg}C around room temperature. For three different arrays, the errors ranged from 0.62-1.42 nm rms/{\\deg}C. Removing the effects of packaging shows that errors are $\\le$0.50 nm rms/{\\deg}C. Finally, measured data showed that individual segments deformed $\\le$0.11 nm rm...

  11. Primate DNA suggests long-term stability of an African rainforest.

    Science.gov (United States)

    Allen, Julie M; Miyamoto, Michael M; Wu, Chieh-Hsi; E Carter, Tamar; Ungvari-Martin, Judit; Magrini, Kristin; Chapman, Colin A

    2012-11-01

    Red colobus monkeys, due to their sensitivity to environmental change, are indicator species of the overall health of their tropical rainforest habitats. As a result of habitat loss and overhunting, they are among the most endangered primates in the world, with very few viable populations remaining. Traditionally, extant indicator species have been used to signify the conditions of their current habitats, but they have also been employed to track past environmental conditions by detecting previous population fluctuations. Kibale National Park (KNP) in Uganda harbors the only remaining unthreatened large population of red colobus. We used microsatellite DNA to evaluate the historical demography of these red colobus and, therefore, the long-term stability of their habitat. We find that the red colobus population throughout KNP has been stable for at least ∼40,000 years. We interpret this result as evidence of long-term forest stability because a change in the available habitat or population movement would have elicited a corresponding change in population size. We conclude that the forest of what is now Kibale National Park may have served as a Late Pleistocene refuge for many East African species.

  12. Long-term stability of conservative orthodontic treatment in a patient with temporomandibular joint disorder

    Science.gov (United States)

    Mitsui, Silvia Naomi; Yasue, Akihiro; Kuroda, Shingo; Tanaka, Eiji

    2016-01-01

    This article reports the orthodontic treatment of a 20-year-old patient with dental crowding and temporomandibular joint disorders (TMDs). The patient presented moderate anterior crowding with a Class I molar relationship and masticatory disturbance in the mandibular position induced by previous splint therapy. Orthodontic treatment with multi-bracket appliance was initiated to correct the anterior crowding in both dental arches, after the extraction of first premolars and third molars, and also to maintain the splint-induced position of the condyles. After 26 months of treatment, an acceptable occlusion was achieved without any TMD symptoms. After 18-month retention, flattening on the right condyle was observed, possibly as an adaptative remodeling. After 16-year retention period, the occlusion was maintained without recurrence of any TMD symptoms, indicating a long-term stability of occlusion and temporomandibular joint (TMJ) components. Our results suggest the possibility of compromised treatment in patients with TMD to achieve a long-term stability in occlusion and TMJ function. PMID:27556023

  13. Long-term stability of conservative orthodontic treatment in a patient with temporomandibular joint disorder.

    Science.gov (United States)

    Mitsui, Silvia Naomi; Yasue, Akihiro; Kuroda, Shingo; Tanaka, Eiji

    2016-01-01

    This article reports the orthodontic treatment of a 20-year-old patient with dental crowding and temporomandibular joint disorders (TMDs). The patient presented moderate anterior crowding with a Class I molar relationship and masticatory disturbance in the mandibular position induced by previous splint therapy. Orthodontic treatment with multi-bracket appliance was initiated to correct the anterior crowding in both dental arches, after the extraction of first premolars and third molars, and also to maintain the splint-induced position of the condyles. After 26 months of treatment, an acceptable occlusion was achieved without any TMD symptoms. After 18-month retention, flattening on the right condyle was observed, possibly as an adaptative remodeling. After 16-year retention period, the occlusion was maintained without recurrence of any TMD symptoms, indicating a long-term stability of occlusion and temporomandibular joint (TMJ) components. Our results suggest the possibility of compromised treatment in patients with TMD to achieve a long-term stability in occlusion and TMJ function.

  14. LTP promotes a selective long-term stabilization and clustering of dendritic spines.

    Directory of Open Access Journals (Sweden)

    Mathias De Roo

    2008-09-01

    Full Text Available Dendritic spines are the main postsynaptic site of excitatory contacts between neurons in the central nervous system. On cortical neurons, spines undergo a continuous turnover regulated by development and sensory activity. However, the functional implications of this synaptic remodeling for network properties remain currently unknown. Using repetitive confocal imaging on hippocampal organotypic cultures, we find that learning-related patterns of activity that induce long-term potentiation act as a selection mechanism for the stabilization and localization of spines. Through a lasting N-methyl-D-aspartate receptor and protein synthesis-dependent increase in protrusion growth and turnover, induction of plasticity promotes a pruning and replacement of nonactivated spines by new ones together with a selective stabilization of activated synapses. Furthermore, most newly formed spines preferentially grow in close proximity to activated synapses and become functional within 24 h, leading to a clustering of functional synapses. Our results indicate that synaptic remodeling associated with induction of long-term potentiation favors the selection of inputs showing spatiotemporal interactions on a given neuron.

  15. Long-term stability of a torque-balance variometer with photoelectric converters in observatory practice

    Science.gov (United States)

    Jankowski, J.; Marianiuk, J.; Ruta, A.; Sucksdorff, C.; Kivinen, M.

    1984-07-01

    Conventional magnetometers of the Bobrov type were equipped with photoelectric converters and feedback loops having a feedback factor of 1000. Tests made at the Belsk and Nurmijärvi Observatories demonstrated that: (a) the long-term stability of the base-line values was the same or better than that in conventional magnetometers (e.g. at Nurmijärvi), i.e. the changes were less than 0.5 nT a month; (b) the short-term stability was the same as in the conventional magnetometers: (c) the reliability of the instrument was good, the time between failures in the instruments tested being more than a year: (d) the same instruments can be used simultaneously for normal recording and for recording magnetic pulsations.

  16. On the Long-Term Stability of Microwave Radiometers Using Noise Diodes for Calibration

    Science.gov (United States)

    Brown, Shannon T.; Desai, Shailen; Lu, Wenwen; Tanner, Alan B.

    2007-01-01

    Results are presented from the long-term monitoring and calibration of the National Aeronautics and Space Administration Jason Microwave Radiometer (JMR) on the Jason-1 ocean altimetry satellite and the ground-based Advanced Water Vapor Radiometers (AWVRs) developed for the Cassini Gravity Wave Experiment. Both radiometers retrieve the wet tropospheric path delay (PD) of the atmosphere and use internal noise diodes (NDs) for gain calibration. The JMR is the first radiometer to be flown in space that uses NDs for calibration. External calibration techniques are used to derive a time series of ND brightness for both instruments that is greater than four years. For the JMR, an optimal estimator is used to find the set of calibration coefficients that minimize the root-mean-square difference between the JMR brightness temperatures and the on-Earth hot and cold references. For the AWVR, continuous tip curves are used to derive the ND brightness. For the JMR and AWVR, both of which contain three redundant NDs per channel, it was observed that some NDs were very stable, whereas others experienced jumps and drifts in their effective brightness. Over the four-year time period, the ND stability ranged from 0.2% to 3% among the diodes for both instruments. The presented recalibration methodology demonstrates that long-term calibration stability can be achieved with frequent recalibration of the diodes using external calibration techniques. The JMR PD drift compared to ground truth over the four years since the launch was reduced from 3.9 to - 0.01 mm/year with the recalibrated ND time series. The JMR brightness temperature calibration stability is estimated to be 0.25 K over ten days.

  17. THE IMPACT OF THE FOREIGN CAPITAL BANKS ON ENSURING FINANCIAL STABILITY ON LONG TERM

    Directory of Open Access Journals (Sweden)

    Isac\tBORS

    2015-06-01

    Full Text Available The present study is focusing on analysing the role played by the foreign banks within the national and international banking system as well the impact the foreign banks have on the autochthon banking system, on the financial activity, on the real economy and on the financial stability on long terms. The research conducted highlights the fact that along the positive impact on the banking system and on the economy of the host country, generated by their quality as vectors of mobilizing and directioning the international financial flows towards the host country, there can also be considered a negative impact. The study shows that the impact of the negative effects, that have as main cause the reversibility of the international financial flows, depends, on a great extent, on the specific conditions of the host country, on the characteristics of the foreign banks, but mostly, by the share held by the foreign countries within the framework of the host banking system. Starting from the role played by the capitalization of the banking system to ensure financial stability, the research made on Romania’s case shows both, the positive effects generated by the presence of the foreign banks and also, their vulnerability in front of this excessive dependence on the foreign capital induced by this presence. The solution to reduce this dependence can only come from the autochthon capital direction whose mobilization may countervail the gap made by the foreign banks and, by surceasing the process of financial disintermediation, to ensure the maintenance of the financial stability on long term.

  18. Fast symplectic mapping and long-term stability near broad resonances

    Energy Technology Data Exchange (ETDEWEB)

    Warnock, R.L. [Stanford Linear Accelerator Center, CA (United States); Berg, J.S. [European Organization for High-Energy Physics (CERN), Geneva (Switzerland)

    1997-04-01

    Fast symplectic mapping, based on a canonical generator of the full-turn map in polar coordinates (I, {Phi}), is a powerful tool to study long-term stability in large hadron storage rings. Accurate maps for realistic lattices can be constructed in a few hours on a workstation computer, and can be iterated to follow orbits for 10{sup 7} turns in less than 4 hours. Orbits of the map can also be used in a non-perturbative construction of quasi-invariant actions. By bounding the small changes in quasi-invariants along many short orbits, one can derive conservative estimates of survival time for long orbits, for any initial condition in a region of phase space. A first quasi-invariant vector, J, arises from a canonical transformation (1, {Phi}) {r_arrow} (J, {Psi}), based on interpolation of invariant tori surrounding the origin. The variation of J is relatively large near a broad resonance. In such a region a second canonical transformation, associated with pendulum-like motion in appropriate variables, is required to produce a good quasi-invariant. This quasi-invariant is used to set a long-term bound on motion near a broad, large-amplitude resonance in a realistic model of the Large Hadron Collider (LHC). Interesting general properties of the pseudo-pendulum motion are studied.

  19. Fast symplectic mapping, quasi-invariants, and long-term stability in the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Warnock, R.L.; Berg, J.S.

    1996-01-01

    A systematic program to explore stability of orbits in hadron storage rings is based on the following steps: (a) beginning with a symplectic tracking code, construct the mixed-variable generator of the full-turn map in a Fourier-spline basis; (b) use the resulting fast mapping to follow long orbits and estimate the long-term dynamic aperture; (c) contruct quasi-invariants and examine their variation in time to set long-term bounds on the motion for any initial condition in a specified region. First results from an application of the program to the Large Hadron Collider (LHC) are reported. Maps can be constructed in a few hours and evaluated at a speed 60 times greater than that of one-turn tracking, on a workstation computer. Orbits of 10{sup 7} turns take 3.6 hours. The value of a ``stroboscopic`` view of the synchro-betatron motion is emphasized. On a Poincare section at multiples of the synchrotron period, one can study resonances and invariant surfaces in two dimensions, thereby taking advantage of techniques that have proved effective in treating pure betatron motion.

  20. Strategic improvement of the long-term stability of perovskite materials and perovskite solar cells.

    Science.gov (United States)

    Xu, Tingting; Chen, Lixin; Guo, Zhanhu; Ma, Tingli

    2016-10-05

    Perovskite solar cells (PSCs) have gained tremendous research interest in recent several years. To date the power conversion efficiency (PCE) of PSCs has been increased from 3.8% to over 22.1%, showing that they have a promising future as a renewable energy resource to compete with conventional silicon solar cells. However, a crucial challenge of PSCs currently is that perovskite materials and PSCs have limitations of easy degradation and inferior long-term stabilities, thus hampering their future commercial applications. In this review, the degradation mechanisms for instable perovskite materials and their corresponding solar cells are discussed. The stability study of perovskite materials and PSCs from the aspect of experimental tests and theoretical calculations is reviewed. The strategies for enhancing the stability of perovskite materials and PSCs are summarized from the viewpoints of perovskite material engineering, substituted organic and inorganic materials for hole transportation, alternative electrodes comprising mainly carbon and its relevant composites, interfacial modification, novel device structure construction and encapsulation, etc. Various approaches and outlooks on the future direction of perovskite materials and PSCs are highlighted. This review is expected to provide helpful insights for further enhancing the stability of perovskite materials and PSCs in this exciting field.

  1. Limitations of long term stability in a coherent population trapping Cs clock

    CERN Document Server

    Kozlova, Olga; Guérandel, Stéphane; de Clercq, Emeric

    2013-01-01

    Vapor cell atomic clocks exhibit reduced frequency stability for averaging time between about one hundred and a few thousand seconds. Here we report a study on the impact of the main parameters on the mid-to-long term instability of a buffer-gas vapor cell Cs clock, based on coherent population trapping (CPT). The CPT signal is observed on the Cs D1 line transmission, using a double $\\Lambda$ scheme and a Ramsey interrogation technique. The effects on the clock frequency of the magnetic field, the cell temperature, and the laser intensities are reported. We show in particular that the laser intensity shift is temperature dependent. Along with the laser intensity ratio and laser polarization properties, this is one of the most important parameters.

  2. The Performance and Long Term Stability of the D0 Run II Forward Muon Scintillation Counters

    Energy Technology Data Exchange (ETDEWEB)

    Bezzubov, V. [Serpukhov, IHEP; Denisov, D. [Fermilab; Evdokimov, V. [Serpukhov, IHEP; Lipaev, V. [Serpukhov, IHEP; Shchukin, A. [Serpukhov, IHEP; Vasilyev, I. [Serpukhov, IHEP

    2014-07-21

    The performance of the D0 experiment forward muon scintillation counters system during Run II of the Tevatron from 2001 to 2011 is described. The system consists of 4214 scintillation counters in six layers. The long term stability of the counters amplitude response determined using LED calibration system and muons produced in proton-antiproton collisions is presented. The average signal amplitude for counters of all layers has gradually decreased over ten years by 11%. The reference timing, determined using LED calibration, was stable within 0.26 ns. Average value of muon timing peak position was used for periodic D0 clock signal adjustments to compensate seasonal drift caused by temperature variations. Counters occupancy for different triggers in physics data collection runs and for minimum bias triggers are presented. The single muon yields versus time and the luminosity dependence of yields were stable for the forward muon system within 1% over 10 years.

  3. Long Term Stability of the LHC Superconducting Cryodipoles after Outdoor Storage

    CERN Document Server

    Seyvet, F; Bertarelli, A; Denis, O; El-Kallassi, P; Fernández-Cano, E D; Fessia, P; Ilie, S D; Jeanneret, J B; Letant, D; Poncet, A; Pugnat, P; Savary, F; Sgobba, Stefano; Siemko, A; Todesco, E; Tommasini, D; Veness, R; Vullierme, B; Wildner, E

    2006-01-01

    The main superconducting dipoles for the LHC are being stored outdoors for periods from a few weeks to several years after conditioning with dry nitrogen gas. Such a storage before installation in the 27 km circumference tunnel may affect not only the mechanical and cryogenic functionality of the cryodipoles but also their quench and field performance. A dedicated task force was established to study all aspects of long term behaviour of the stored cryodipoles, with particular emphasis on electrical and vacuum integrity, quench training behaviour, magnetic field quality, performance of the thermal insulation, mechanical stability of magnet shape and of the interface between cold mass and cryostat, degradation ofmaterials and welds. In particular, one specifically selected cryodipole stored outdoors for more than one year, was retested at cold. In addition, various tests have been carried out on the cryodipole assembly and on the most critical subcomponents to study aspects such as the hygrothermal behaviour of...

  4. Long-term stability improvement of light-emitting diode using highly transparent graphene oxide paste.

    Science.gov (United States)

    Lee, Seungae; Kim, Yun Ki; Jang, Jyongsik

    2016-10-14

    A highly transparent paste adhesive is successfully fabricated by introducing graphene oxide (GO) to silicone paste adhesive by using a solvent-exchange method. The GO incorporated in the paste adhesive has a significant role in improving thermal conductivity, transparency and adhesive strength. The GO-embedded silicone paste is applied as a die-attach paste to light-emitting diodes (LEDs) in order to enhance the optical quality of the LEDs. The presence of GO in the die-attach layer of the LEDs gives rise to the enhancement of luminous intensity, effective heat dissipation, improvement of moisture barrier property as well as high adhesive strength. Consequently, the LEDs with the GO-embedded die-attach paste exhibit enhanced long-term stability. This novel approach provides a feasible and effective strategy for improving LED performance.

  5. Analysis and research of long-term stability about the gob site in Northern Shaanxi Province

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi-pei; PENG Hui

    2011-01-01

    Based on the analysis of the basic characteristics for the gob site in Northern Shaanxi Province and the room and pillar mining way about coal mine, the variety rule of the coal beds below the site was studied by the using of FEM during the process of coal mining. The statuses of the stresses and strains and the varieties of the plastic area were simulated in the whole rock and coal pillars. The characters of stresses and deformation of the gob area of the coalmine were analyzed and evaluated after the site built in weathering. Moreover, the long-term stability of the gob area was predicted. As a result, the deformation of the gob area under the site is not been finished, and there is the danger that the gob site will collapsing as a whole; therefore,relative measures must be taken.

  6. Long-Term Physical Stability of PVP- and PVPVA-Amorphous Solid Dispersions.

    Science.gov (United States)

    Lehmkemper, Kristin; Kyeremateng, Samuel O; Heinzerling, Oliver; Degenhardt, Matthias; Sadowski, Gabriele

    2017-01-03

    The preparation of amorphous solid dispersion (ASD) formulations is a promising strategy to improve the bioavailability of an active pharmaceutical ingredient (API). By dissolving the API in a polymer it is stabilized in its amorphous form, which usually shows higher water solubility than its crystalline counterpart. To prevent recrystallization, the long-term physical stability of ASD formulations is of big interest. In this work, the solubility of the APIs acetaminophen and naproxen in the excipient polymers poly(vinylpyrrolidone) (PVP K25) and poly(vinylpyrrolidone-co-vinyl acetate) (PVPVA64) was calculated with three models: the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT), the Flory-Huggins model (FH), and an empirical model (Kyeremateng et al., J. Pharm. Sci, 2014, 103, 2847-2858). PC-SAFT and FH were further used to predict the influence of relative humidity (RH) on the API solubility in the polymers. The Gordon-Taylor equation was applied to model the glass-transition temperature of dry ASD and at humid conditions. The calculations were validated by 18 months-long stability studies at standardized storage conditions, 25 °C/0% RH, 25 °C/60% RH, and 40 °C/75% RH. The results of the three modeling approaches for the API solubility in polymers agreed with the experimental solubility data, which are only accessible at high temperatures in dry polymers. However, at room temperature FH resulted in a lower solubility of the APIs in the dry polymers than PC-SAFT and the empirical model. The impact of RH on the solubility of acetaminophen was predicted to be small, but naproxen solubility in the polymers was predicted to decrease with increasing RH with both, PC-SAFT and FH. At 25 °C/60% RH and 40 °C/75% RH, PC-SAFT is in agreement with all results of the long-term stability studies, while FH underestimates the acetaminophen solubility in PVP K25 and PVPVA64.

  7. Fundamental study on long-term stability of rock from the macroscopic point of view

    Energy Technology Data Exchange (ETDEWEB)

    Okubo, Seisuke [Tokyo Univ. (Japan). Faculty of Engineering

    1998-03-01

    In 1994, this project was started. A pneumatic creep testing machine was modified. Inada granite was purchased, and the preliminary tests were carried out. In 1995, a specimen of Tage tuff under water-saturated condition had been loaded in uniaxial condition in the pneumatic creep testing machine. The uniaxial compression and tension tests, and the short-term creep test of Inada granite were also carried out in the servo-controlled testing machines to obtain the complete stress-strain curves. In 1996, creep, compression and tension tests were carried out. Two types of pressure maintenance equipment (hydraulic and pneumatic types) were developed. In 1997, creep, compression and tension tests etc. were again carried out on the basis of the results heretofore. The experimental results of long-term creep testing of Tage tuff are, and of middle-term creep testing of Inada granite, are described. Two types of pressure maintenance equipment were developed and examined in 1996. One was hydraulic type and another was pneumatic type. The hydraulic type equipment modified for long-term creep testing especially in the measurement system to ensure durability and stability was found to be precise and reliable. The results of triaxial compression test are described. In 1997, a specimen was unloaded and re-loaded through a uniaxial tension test to obtain behaviour more precisely. A constitutive equation of variable compliance type was discussed based on the experimental results. Though the equation has relatively simple form, it can be applied beyond the strength failure point up to the post-failure region. The constitutive equation was implemented in two and three dimensional FEM programs. Preliminary evaluation of equipment and materials for pore-pressure controlled testing was described. (J.P.N.)

  8. Thermal stability of the French nuclear waste glass - long term behavior modeling; Etude de la stabilite thermique du verre nucleaire. Modelisation de son evolution a long terme

    Energy Technology Data Exchange (ETDEWEB)

    Orlhac, X

    2000-07-01

    The thermal stability of the French nuclear waste glass was investigated experimentally and by modeling to predict its long-term evolution at low temperature. The crystallization mechanisms were analyzed by studying devitrification in the supercooled liquid. Three main crystalline phases were characterized (CaMoO{sub 4}, CeCO{sub 2}, ZnCr{sub 2}O{sub 4}). Their crystallisation was TO 4.24 wt%, due to the low concentration of the constituent elements. The nucleation and growth curves showed that platinoid elements catalysed nucleation but did not affect growth, which was governed by volume diffusion. The criteria of classic nucleation theory were applied to determine the thermodynamic and diffusional activation energies. Viscosity measurements illustrate the analogy between the activation energy of viscous flow and diffusion, indicating control of crystallization by viscous flow phenomena. The combined action of nucleation and growth was assessed by TTT plots, revealing a crystallization equilibrium line that enables the crystallized fractions to be predicted over the long term. The authors show that hetero-genetics catalyze the transformation without modifying the maximum crystallized fraction. A kinetic model was developed to describe devitrification in the glass based on the nucleation and growth curves alone. The authors show that the low-temperature growth exhibits scale behavior (between time and temperature) similar to thermo-rheological simplicity. The analogy between the resulting activation energy and that of the viscosity was used to model growth on the basis of viscosity. After validation with a simplified (BaO{sub 2}SiO{sub 2}) glass, the model was applied to the containment glass. The result indicated that the glass remained completely vitreous after a cooling scenario with the one measured at the glass core. Under isothermal conditions, several million years would be required to reach the maximum theoretical crystallization fraction. (author)

  9. Short-term and long-term stability of surgically assisted rapid palatal expansion revisited

    Science.gov (United States)

    Chamberland, Sylvain; Proffit, William R.

    2014-01-01

    Introduction The purpose of this article is to present further longitudinal data for short-term and long-term stability, following up our previous article in the surgery literature with a larger sample and 2 years of stability data. Methods Data from 38 patients enrolled in this prospective study were collected before treatment, at maximum expansion, at removal of the expander 6 months later, before any second surgical phase, at the end of orthodontic treatment, and at the 2-year follow-up, by using posteroanterior cephalograms and dental casts. Results With surgically assisted rapid palatal expansion (SARPE), the mean maximum expansion at the first molar was 7.60 ± 1.57 mm, and the mean relapse was 1.83 ± 1.83 mm (24%). Modest relapse after completion of treatment was not statistically significant for all teeth except for the maxillary first molar (0.99 ± 1.1 mm). A significant relationship (P <0.0001) was observed between the amount of relapse after SARPE and the posttreatment observation. At maximum, a skeletal expansion of 3.58 ± 1.63 mm was obtained, and this was stable. Conclusions Skeletal changes with SARPE were modest but stable. Relapse in dental expansion was almost totally attributed to lingual movement of the posterior teeth; 64% of the patients had more than 2 mm of dental changes. Phase 2 surgery did not affect dental relapse. PMID:21640889

  10. Long-Term Stability of WC-C Peritectic Fixed Point

    Science.gov (United States)

    Khlevnoy, B. B.; Grigoryeva, I. A.

    2015-03-01

    The tungsten carbide-carbon peritectic (WC-C) melting transition is an attractive high-temperature fixed point with a temperature of . Earlier investigations showed high repeatability, small melting range, low sensitivity to impurities, and robustness of WC-C that makes it a prospective candidate for the highest fixed point of the temperature scale. This paper presents further study of the fixed point, namely the investigation of the long-term stability of the WC-C melting temperature. For this purpose, a new WC-C cell of the blackbody type was built using tungsten powder of 99.999 % purity. The stability of the cell was investigated during the cell aging for 50 h at the cell working temperature that tooks 140 melting/freezing cycles. The method of investigation was based on the comparison of the WC-C tested cell with a reference Re-C fixed-point cell that reduces an influence of the probable instability of a radiation thermometer. It was shown that after the aging period, the deviation of the WC-C cell melting temperature was with an uncertainty of.

  11. Long-term stability of the Tevatron by verified global optimization

    Science.gov (United States)

    Berz, Martin; Makino, Kyoko; Kim, Youn-Kyung

    2006-03-01

    The tools used to compute high-order transfer maps based on differential algebraic (DA) methods have recently been augmented by methods that also allow a rigorous computation of an interval bound for the remainder. In this paper we will show how such methods can also be used to determine rigorous bounds for the global extrema of functions in an efficient way. The method is used for the bounding of normal form defect functions, which allows rigorous stability estimates for repetitive particle accelerator. However, the method is also applicable to general lattice design problems and can enhance the commonly used local optimization with heuristic successive starting point modification. The global optimization approach studied rests on the ability of the method to suppress the so-called dependency problem common to validated computations, as well as effective polynomial bounding techniques. We review the linear dominated bounder (LDB) and the quadratic fast bounder (QFB) and study their performance for various example problems in global optimization. We observe that the method is superior to other global optimization approaches and can prove stability times similar to what is desired, without any need for expensive long-term tracking and in a fully rigorous way.

  12. Long-term thermal stability of group C meningococcal polysaccharide-tetanus toxoid conjugate vaccine.

    Science.gov (United States)

    Lee, Shwu-Maan; Petermann, Robert; Porte, Quallyna; Berezuk, Greg; Crowe, Brian; Shirtz, John

    2007-01-01

    The stability of vaccines during storage and handling is a prerequisite for optimal potency at the time of immunization. Meningococcal group C conjugate vaccines have been successfully incorporated in mass immunization programs, however, thus far no long-term real-time stability studies of these vaccines have been reported. Stability of de-O-acetylated group C meningococcal polysaccharide coupled to tetanus toxoid (GCMP-TT) was evaluated in real time on the basis of immunogenicity and physiochemical properties. The vaccine is formulated as a 0.5 mL suspension containing 10 mug GCMP conjugated to 10-20 mug of TT adsorbed on 0.5 mg aluminum in saline. The single dose syringes were stored under refrigeration (5 +/- 3 degrees C) and at room temperature (25 +/- 2 degrees C) for up to 42 months and at elevated temperature (40 +/- 2 degrees C) for up to 6 months. At both refrigerated and room temperatures, no time-dependent change in animal potency was detectable through 42 months. After the nine months maximum recommended storage period at room temperature, 96% of the baseline serum bactericidal antibody (SBA) titer was maintained. Time-dependent decreases in SBA level and anti-GCMP-TT IgG level were observed at 40 +/- 2 degrees C. No changes in GCMP-TT adsorption and pH occurred in all the studies. Loss of integrity increased over six months at 40 +/- 2 degrees C (p = 0.004). Free sugar content did not change over 36 months under refrigeration. GCMP-TT retained immunogenicity and physicochemical properties under refrigeration and at room temperature (25 +/- 2 degrees C) for up to 42 months.

  13. Long term stabilization of reaction center protein photochemistry by carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Magyar, Melinda; Hajdu, Kata; Szabo, Tibor; Nagy, Laszlo [Department of Medical Physics and Informatics, University of Szeged, 6720 Szeged (Hungary); Hernadi, Klara [Department of Applied and Environmental Chemistry, University of Szeged, 6720 Szeged (Hungary); Dombi, Andras [Institute of Material Sciences and Engineering, University of Szeged, 6701 Szeged (Hungary); Horvath, Endre; Magrez, Arnaud; Forro, Laszlo [Institute of Physics of Complex Matter, Ecole Polytechnique Federale de Lausanne, 1015 Lausanne (Switzerland)

    2011-11-15

    The long term stability and the redox interaction between single walled carbon nanotubes (SWNTs) and photosynthetic reaction center proteins (RCs) purified from purple bacterium Rhodobacter sphaeroides R-26 in the SWNT/RC complex has been investigated. The binding of SWNT to RC results in an accumulation of positive (the oxidized primary electron donor, P{sup +}) and negative (semiquinone forms, Q{sup -}{sub A} and Q{sup -}{sub B}, the reduced primary and secondary quinones, respectively) charges followed by slow reorganization of the protein structure after excitation. The photochemical activity of the SWNT/RC complexes remains stable for several weeks even in dried form. In the absence of SWNT the secondary quinone activity decays quickly as a function of time after drying the RC onto a glass surface. Polarography measurements substantiate the idea that there is an electronic interaction between the RCs and SWNTs after light excitation, which was suggested earlier by optical measurements. The special electronic properties of the SWNT/protein complexes open the possibility for several applications, e.g., in microelectronics, analytics, or energy conversion and storage. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Microstructure Stability of Inconel 740H Alloy After Long Term Exposure at 750℃

    Directory of Open Access Journals (Sweden)

    DANG Ying-ying

    2016-09-01

    Full Text Available Unstressed exposure tests of Inconel 740H alloy tube were carried out at 750℃ for 500-3000h. The microstructure evolution and microhardness were studied by means of thermodynamic simulation, OM, FEG-SEM and microhardness testing. The results show that the tube is qualified if both chemical composition and tensile properties of the as-received alloy meet the corresponding requirements of ASME. After long term exposure, the main precipitates are γ' and M23C6, and no η and σ phase. With the prolonging of exposure time, the coarsening of γ' becomes faster and the law of relationship between the radius of γ' and time accords with LSW Ostwald ripening law; meanwhile, the change in size of M23C6 is not so obvious. During the whole process, microhardness increases firstly and then decreases, but the fluctuation is slight. The changes of microstructure and hardness indicate that, after long time exposure, the domestic Inconel 740H has good stability and can be used for further carrying out the investigation on the mechanical property of creep-rupture.

  15. Amorphous iron–chromium oxide nanoparticles with long-term stability

    Energy Technology Data Exchange (ETDEWEB)

    Iacob, Mihail [“Petru Poni” Institute of Macromolecular Chemistry, Iasi 700487 (Romania); Institute of Chemistry of ASM, Academiei str. 3, Chisinau 2028, Republic of Moldova (Moldova, Republic of); Cazacu, Maria, E-mail: mcazacu@icmpp.ro [“Petru Poni” Institute of Macromolecular Chemistry, Iasi 700487 (Romania); Turta, Constantin [Institute of Chemistry of ASM, Academiei str. 3, Chisinau 2028, Republic of Moldova (Moldova, Republic of); Doroftei, Florica [“Petru Poni” Institute of Macromolecular Chemistry, Iasi 700487 (Romania); Botko, Martin; Čižmár, Erik; Zeleňáková, Adriana; Feher, Alexander [Institute of Physics, Faculty of Science, P.J. Šafárik University, Park Angelinum 9, SK-04154 Košice (Slovakia)

    2015-05-15

    Highlights: • Fe–Cr oxide nanoparticles with pre-established metals ratio were obtained. • The amorphous state and its long-term stability were highlighted by X-ray diffraction. • The average diameter of dried nanoparticles was 3.5 nm, as was estimated by TEM, AFM. • In hexane dispersion, nanoparticles with diameter in the range 2.33–4.85 nm were found. • Superparamagnetic state of NPs co-exists with diamagnetism of the organic layer. - Abstract: Iron–chromium nanoparticles (NPs) were obtained through the thermal decomposition of μ{sub 3}-oxo heterotrinuclear (FeCr{sub 2}O) acetate in the presence of sunflower oil and dodecylamine (DA) as surfactants. The average diameter of the NPs was 3.5 nm, as estimated on the basis of transmission electron microscopy and atomic force microscopy images. Both techniques revealed the formation of roughly approximated spheres with some irregularities and agglomerations in larger spherical assemblies of 50–100 nm. In hexane, NPs with diameters in the 2.33–4.85 nm range are individually dispersed, as emphasized by dynamic light scattering measurements. The amorphous nature of the product was emphasized by X-ray powder diffraction. The study of the magnetic properties shows the presence of superparamagnetic state of iron–chromium oxide NPs and the diamagnetic contribution from DA layer forming a shell of NPs.

  16. Long-term stability, biocompatibility and oral delivery potential of risperidone-loaded solid lipid nanoparticles.

    Science.gov (United States)

    Silva, A C; Kumar, A; Wild, W; Ferreira, D; Santos, D; Forbes, B

    2012-10-15

    A solid lipid nanoparticles (SLN) formulation to improve the oral delivery of risperidone (RISP), a poorly water-soluble drug, was designed and tested. Initially, lipid-RISP solubility was screened to select the best lipid for SLN preparation. Compritol(®)-based formulations were chosen and their long-term stability was assessed over two years of storage (at 25 °C and 4 °C) by means of particle size, polydispersity index (PI), zeta potential (ZP) and encapsulation efficiency (EE) measurements. SLN shape was observed by transmission electron microscopy (TEM) at the beginning and end of the study. The oxidative potential (OP) of the SLN was measured and their biocompatibility with Caco-2 cells was evaluated using the (4,5-dimethylthiazol-2-yl)2,5-dyphenyl-tetrazolium bromide (MTT) assay. In vitro drug release and transport studies were performed to predict the in vivo release profile and to evaluate the drug delivery potential of the SLN formulations, respectively. The RISP-loaded SLN systems were stable and had high EE and similar shape to the placebo formulations before and after storage. Classical Fickian diffusion was identified as the release mechanism for RISP from the SLN formulation. Biocompatibility and dose-dependent RISP transport across Caco-2 cells were observed for the prepared SLN formulations. The viability of SLN as formulations for oral delivery of poorly water-soluble drugs such as RISP was illustrated.

  17. Numerical investigation of long-term planform dynamics and stability of river meandering on fluvial floodplains

    Science.gov (United States)

    Xu, Dong; Bai, Yuchuan; Ma, Jianmin; Tan, Yan

    2011-09-01

    A mathematical model for river meandering and floodplain development is presented under the assumption of constant channel width, which combined Johanneson and Parker (1989) linear theory for flows in river bends and a conceptual depositional model from Howard (1992). A new bank erosion model is also developed, which takes into consideration of the nonlinearity in near-bank velocity and the outer bank height. Simulations reproduce the long-term behavior of river meandering and floodplain evolution in a way very similar to their natural processes. Based on the simulation results, stability of river meandering dynamics is discussed and the concept of filtration effect is introduced to highlight meandering rivers' capability to filter out arbitrarily applied planform disturbance. Simulations are also carried out to investigate the influence of the velocity nonlinearity and the outer bank height in bank erosion model, as well as their combinations. Results show that the consideration of velocity nonlinearity in bank erosion model leads to highly upstream-skewing geometry of fully developed river meanders, as well as a slower downstream migration of meander trains. The influence of nonlinearity in bank erosion model is much smaller than the influence of bank height, which reduces the bank migration rate exponentially in the newly introduced bank erosion model. The outer bank height consideration tends to decelerate the downstream migration rate of river meanders and accelerate lateral expansion of the floodplain as well. Consequently, a broader floodplain is generated compared with simulations without bank height considerations.

  18. Improved long-term stability of blood cocaine in evacuated collection tubes.

    Science.gov (United States)

    Baselt, R C; Yoshikawa, D; Chang, J; Li, J

    1993-07-01

    A study was undertaken to determine if a relatively minor modification of our existing specimen collection tubes could enhance the long-term stability of blood cocaine. We added cocaine, benzoylecgonine (BE) and ethanol to whole sheep blood in glass tubes that were prepared to contain one of several combinations of preservatives and anticoagulant. On day 1 and at intervals of up to one year, the drugs were measured by gas chromatography-mass spectrometry (cocaine and BE) or headspace gas chromatography (ethanol). Storage of blood containing 200 ng/mL cocaine at 4 degrees C for one year resulted in 100% loss of the drug using our normal 10 mL specimen collection tubes containing 100 mg sodium fluoride and 20 mg potassium oxalate. The substitution of oxalic acid for potassium oxalate reduced this loss to 76% without any significant effect on the benzoylecgonine or ethanol concentrations. Further addition of 10 mg echothiophate iodide, a quaternary ammonium compound, brought the cocaine loss down to 60% of the original concentration by one year. Further work will be required to determine if oxalic acid and/or echothiophate iodide could be used in blood collection vials intended for forensic toxicological purposes without any detrimental effect on other assays.

  19. Stabilization of soil hydraulic properties under a long term no-till system

    Directory of Open Access Journals (Sweden)

    Luis Alberto Lozano

    2014-08-01

    Full Text Available The area under the no-tillage system (NT has been increasing over the last few years. Some authors indicate that stabilization of soil physical properties is reached after some years under NT while other authors debate this. The objective of this study was to determine the effect of the last crop in the rotation sequence (1st year: maize, 2nd year: soybean, 3rd year: wheat/soybean on soil pore configuration and hydraulic properties in two different soils (site 1: loam, site 2: sandy loam from the Argentinean Pampas region under long-term NT treatments in order to determine if stabilization of soil physical properties is reached apart from a specific time in the crop sequence. In addition, we compared two procedures for evaluating water-conducting macroporosities, and evaluated the efficiency of the pedotransfer function ROSETTA in estimating the parameters of the van Genuchten-Mualem (VGM model in these soils. Soil pore configuration and hydraulic properties were not stable and changed according to the crop sequence and the last crop grown in both sites. For both sites, saturated hydraulic conductivity, K0, water-conducting macroporosity, εma, and flow-weighted mean pore radius, R0ma, increased from the 1st to the 2nd year of the crop sequence, and this was attributed to the creation of water-conducting macropores by the maize roots. The VGM model adequately described the water retention curve (WRC for these soils, but not the hydraulic conductivity (K vs tension (h curve. The ROSETTA function failed in the estimation of these parameters. In summary, mean values of K0 ranged from 0.74 to 3.88 cm h-1. In studies on NT effects on soil physical properties, the crop effect must be considered.

  20. Engineered Barrier System - Long-term Stability of Buffer and Backfill. Synthesis and extended abstracts

    Energy Technology Data Exchange (ETDEWEB)

    Apted, Mick; Arthur, Randy [Monitor Scientific LLC, Denver, CO (United States); Savage, Dave [Quintessa Ltd., Nottingham (GB)] (eds.)

    2005-09-15

    SKI is preparing to review the license applications being developed by the Swedish Nuclear Fuel and Waste Management Company (SKB) for an encapsulation plant and a deep repository for the geological disposal of spent nuclear fuel. As part of its preparation, SKI is conducting a series of technical workshops on key aspects of the Engineered Barrier System (EBS) of the repository. This workshop concerns the longterm stability of the buffer and the backfill. Previous workshops have addressed the overall concept for long-term integrity of the EBS, the manufacturing, testing and QA of the EBS and the performance confirmation for the EBS. The goal of this work is to achieve a comprehensive overview of all aspects of SKB's EBS work prior to the handling of forthcoming license applications. The reports from the EBS workshops will be used as one important basis in future review work. The workshops involve the gathering of a sufficient number of independent experts in different subjects of relevance to the particular aspect of EBS. A workshop starts with presentations and discussions among these experts. Following this, SKB presents recent results and responds to questions as part of an informal hearing. Finally, the independent experts and the SKI staff examine the SKB responses from different viewpoints. This report aims to summarise the issues discussed at the buffer and backfill workshop and to extract the essential viewpoints that have been expressed. The report is not a comprehensive record of the discussions and individual statements made by workshop participants should be regarded as opinions rather than proven facts. This reports includes apart from the workshop synthesis, questions to SKB identified prior or during the workshop, and extended abstracts for introductory presentations.

  1. Long-term stability of a TLD-based individual monitoring system.

    Science.gov (United States)

    Alves, J G; Abrantes, J N; Margo, O; Rangel, S; Santos, L

    2006-01-01

    The thermoluminescence dosemeter (TLD) system at the Individual Monitoring Service (IMS) of the Nuclear Technology Institute (ITN) at the Radiological Protection and Nuclear Safety Department (DPRSN) comprises two 6600 Harshaw readers and the Harshaw 8814 TL card and the holder containing two LiF:Mg,Ti (TLD-100) dosemeters for the evaluation of H(p)(10) and H(p)(0.07). The readers are calibrated on a monthly basis and as part of the quality assurance programme implemented at the IMS a set of dosemeters is issued monthly to the DPRSN's Standard Dosimetry Laboratory for linearity measurements. The results obtained since November 2001 are presented. Fading and sensitivity change experiments are carried out every month covering 8 week periods so that enough time is given to simulate issuing, integrating and receiving times and respective delays. A set of 96 dosemeters organised in eight subsets of 12 are used. In each subset, four dosemeters are irradiated and stored at room temperature (RT), four are not irradiated at all and the last four are irradiated after storage. The 12 dosemeters of each subset are readout at the same time, one per week, covering the 8 week period. The results from the sets irradiated and stored at different periods allowed for the evaluation of fading and sensitivity changes experienced over the whole monitoring period and respective preparation time and readout delays. Time evolution charts of the reader calibration factors, of the linearity parameters and of the evolution of the integrated area in the region of dosimetric interest with storage at RT were obtained. This paper aims to quantify the long-term stability of the TLD system in use at the IMS.

  2. Long-term stability for cobalt-based dye-sensitized solar cells obtained by electrolyte optimization.

    Science.gov (United States)

    Gao, Jiajia; Bhagavathi Achari, Muthuraaman; Kloo, Lars

    2014-06-14

    A significant improvement in the long-term stability for cobalt-based dye-sensitized solar cells (DSCs) under light-soaking conditions has been achieved by optimization of the composition of tris(2,2'-bipyridine) Co(ii)/Co(iii) electrolytes. The effects of component exchanges and changes were also studied during the optimization process.

  3. The Franck Test for Gender Identity: Correlation with Occupation and Long-Term Stability of Score in Normal Men.

    Science.gov (United States)

    Berg, Roland

    1985-01-01

    A correlation was found between high (independent) occupational positions and masculine scores on the Franck Drawing Completion Test (FDCT). Acceptable individual long-term stability was also evident. The FDCT appears to be useful in assessing gender identity. (Author/ABB)

  4. Surface shear rheology of hydrophobin adsorption layers: laws of viscoelastic behaviour with applications to long-term foam stability

    NARCIS (Netherlands)

    Danov, K.D.; Radulova, G.M.; Kralchevsky, P.A.; Golemanov, K.; Stoyanov, S.D.

    2012-01-01

    The long-term stabilization of foams by proteins for food applications is related to the ability of proteins to form dense and mechanically strong adsorption layers that cover the bubbles in the foams. The hydrophobins represent a class of proteins that form adsorption layers of extraordinary high s

  5. Mainstream partial nitritation and anammox: long-term process stability and effluent quality at low temperatures.

    Science.gov (United States)

    Laureni, Michele; Falås, Per; Robin, Orlane; Wick, Arne; Weissbrodt, David G; Nielsen, Jeppe Lund; Ternes, Thomas A; Morgenroth, Eberhard; Joss, Adriano

    2016-09-15

    The implementation of autotrophic anaerobic ammonium oxidation processes for the removal of nitrogen from municipal wastewater (known as "mainstream anammox") bears the potential to bring wastewater treatment plants close to energy autarky. The aim of the present work was to assess the long-term stability of partial nitritation/anammox (PN/A) processes operating at low temperatures and their reliability in meeting nitrogen concentrations in the range of typical discharge limits below 2  [Formula: see text] and 10 mgNtot·L(-1). Two main 12-L sequencing batch reactors were operated in parallel for PN/A on aerobically pre-treated municipal wastewater (21 ± 5 [Formula: see text] and residual 69 ± 19 mgCODtot·L(-1)) for more than one year, including over 5 months at 15 °C. The two systems consisted of a moving bed biofilm reactor (MBBR) and a hybrid MBBR (H-MBBR) with flocculent biomass. Operation at limiting oxygen concentrations (0.15-0.18 [Formula: see text] ) allowed stable suppression of the activity of nitrite-oxidizing bacteria at 15 °C with a production of nitrate over ammonium consumed as low as 16% in the MBBR. Promising nitrogen removal rates of 20-40 mgN·L(-1)·d(-1) were maintained at hydraulic retention times of 14 h. Stable ammonium and total nitrogen removal efficiencies over 90% and 70% respectively were achieved. Both reactors reached average concentrations of total nitrogen below 10 mgN·L(-1) in their effluents, even down to 6 mgN·L(-1) for the MBBR, with an ammonium concentration of 2 mgN·L(-1) (set as operational threshold to stop aeration). Furthermore, the two PN/A systems performed almost identically with respect to the biological removal of organic micropollutants and, importantly, to a similar extent as conventional treatments. A sudden temperature drop to 11 °C resulted in significant suppression of anammox activity, although this was rapidly recovered after the temperature was increased back to 15 °C. Analyses of 16S

  6. The resonant structure of Jupiter's Trojan asteroids - I. Long-term stability and diffusion

    Science.gov (United States)

    Robutel, P.; Gabern, F.

    2006-11-01

    We study the global dynamics of the jovian Trojan asteroids by means of the frequency map analysis. We find and classify the main resonant structures that serve as skeleton of the phase space near the Lagrangian points. These resonances organize and control the long-term dynamics of the Trojans. Besides the secondary and secular resonances, that have already been found in other asteroid sets in mean motion resonance (e.g. main belt, Kuiper belt), we identify a new type of resonance that involves secular frequencies and the frequency of the great inequality, but not the libration frequency. Moreover, this new family of resonances plays an important role in the slow transport mechanism that drives Trojans from the inner stable region to eventual ejections. Finally, we relate this global view of the dynamics with the observed Trojans, identify the asteroids that are close to these resonances and study their long-term behaviour.

  7. The long term effects of cathodic protection on corroding, pre-stressed concrete structures: Hydrogen embrittlement of the reinforcing steel

    Science.gov (United States)

    Enos, David George

    Assessment of the effect of cathodic protection on a chloride contaminated bridge pile involves the definition of the hydrogen embrittlement behavior of the pearlitic reinforcement combined with quantification of the local (i.e., at the steel/concrete interface) chemical and electrochemical conditions, both prior to and throughout the application of cathodic protection. The hydrogen embrittlement behavior of the reinforcement was assessed through a combination of Devanathan/Stachurski permeation experiments to quantify subsurface hydrogen concentrations, CsbH, as a function of the applied hydrogen overpotential, eta, and crack initiation tests for bluntly notched and fatigue pre-cracked tensile specimens employing elastic-plastic finite element analysis and linear elastic fracture mechanics, respectively. A threshold mobile lattice hydrogen concentration for embrittlement of 2×10sp{-7} mol/cmsp3 was established for bluntly notched and fatigue pre-cracked specimens. Crack initiation occurred by the formation of shear cracks oriented at an angle approaching 45sp° from the tensile axis, as proposed by Miller and Smith (Miller, 1970), in regions where both the longitudinal and shear stresses were maximized (i.e., near the notch root). These Miller cracks then triggered longitudinal splitting which continued until fast fracture of the remaining ligament occurred. Instrumented laboratory scale piles were constructed and partially immersed in ASTM artificial ocean water. With time, localized corrosion (crevicing) was initiated along the reinforcement, and was accompanied by an acidic shift in the pH of the occluded environment due to ferrous ion hydrolysis. Cathodic protection current densities from -0.1 muA/cmsp2 to -3.0 muA/cmsp2 were applied via a skirt anode located at the waterline. Current densities as low as 0.66 muA/cmsp2 were sufficient to deplete the dissolved oxygen concentration at the steel/concrete interface and result in the observance of hydrogen

  8. Highly Efficient Organic Hole Transporting Materials for Perovskite and Organic Solar Cells with Long-Term Stability.

    Science.gov (United States)

    Reddy, Saripally Sudhaker; Gunasekar, Kumarasamy; Heo, Jin Hyuck; Im, Sang Hyuk; Kim, Chang Su; Kim, Dong-Ho; Moon, Jong Hun; Lee, Jin Yong; Song, Myungkwan; Jin, Sung-Ho

    2016-01-27

    Small molecules based on N-atom-linked phenylcarbazole-fluorene as the main scaffold, end-capped with spirobifluorene derivatives, are developed as organic hole-transporting materials for highly efficient perovskite solar cells (PSCs) and bulk heterojunction (BHJ) inverted organic solar cells (IOSCs). The CzPAF-SBF-based devices show remarkable device performance with excellent long-term stability in PSCs and BHJ IOSCs with a maximum PCE of 17.21% and 7.93%, respectively.

  9. Long-Term Evolution of Email Networks: Statistical Regularities, Predictability and Stability of Social Behaviors.

    Science.gov (United States)

    Godoy-Lorite, Antonia; Guimerà, Roger; Sales-Pardo, Marta

    2016-01-01

    In social networks, individuals constantly drop ties and replace them by new ones in a highly unpredictable fashion. This highly dynamical nature of social ties has important implications for processes such as the spread of information or of epidemics. Several studies have demonstrated the influence of a number of factors on the intricate microscopic process of tie replacement, but the macroscopic long-term effects of such changes remain largely unexplored. Here we investigate whether, despite the inherent randomness at the microscopic level, there are macroscopic statistical regularities in the long-term evolution of social networks. In particular, we analyze the email network of a large organization with over 1,000 individuals throughout four consecutive years. We find that, although the evolution of individual ties is highly unpredictable, the macro-evolution of social communication networks follows well-defined statistical patterns, characterized by exponentially decaying log-variations of the weight of social ties and of individuals' social strength. At the same time, we find that individuals have social signatures and communication strategies that are remarkably stable over the scale of several years.

  10. Long-term stability of grafted polyethylene glycol surfaces for use with microstamped substrates in neuronal cell culture.

    Science.gov (United States)

    Branch, D W; Wheeler, B C; Brewer, G J; Leckband, D E

    2001-05-01

    Crucial to long-term stability of neuronal micropatterns is functional retention of the underlying substratum while exposed to cell culture conditions. We report on the ability of covalently bound PEG films in long-term cell culture to continually retard protein adhesion and cell growth. PDMS microstamps were used to create poly-d-lysine (PDL) substrates permissive to cell attachment and growth, and polyethylene glycol (PEG) substrates were used to minimize protein and cell adhesion. Film thickness was measured using null ellipsometry and atomic force microscopy (AFM). Organosilane film structure was examined using Fourier transform infrared (FT-IR) spectroscopy. Long-term film stability in cell culture conditions was tested by immersion in 0.1 M sodium phosphate buffer pH 7.4 for up to one month. Null ellipsometry and water contact measurements indicated that organosilane films were stable up to one month, whereas the PEG film thickness declined rapidly after day 25. Hippocampal cells plated at 200 cells/mm2 on uniform PEG substrates gave a steady increase in biofilm thickness on PEG films throughout the culture, possibly from proteins of neuronal origin. We found that all the layers in the cross-linking procedure were stable in cell culture conditions, with the exception of PEG, which degraded after day 25.

  11. Microstructural Stability of 316 Stainless Steel During Long Term Exposure to High Magnetic Fields at Cryogenic Temperatures

    Science.gov (United States)

    Nishimura, A.; Kakeshita, T.

    2004-06-01

    The effect of long term exposure to high magnetic fields at cryogenic temperatures on the microstructural stability of austenitic stainless steel was investigated. Three samples of SUS316 were prepared. One was as-machined, the second was solution heat-treated, and the last was solution heat-treated followed by a sensitization heat treatment. The samples were attached to the helical coil cover of the Large Helical Device, which is a large plasma experimental device operating with a superconducting magnet system. The maximum magnetic field the samples experienced was about 2.56 T for over 100 cycles during which time the temperature was kept at about 4.5 K for approximately 300 days. Before and after the exposure, the susceptibility was measured by a superconducting quantum interference device and it was confirmed that the austenitic phase was stable and did not produce any additional martensite by the long term exposure to the high magnetic fields at cryogenic temperatures.

  12. Macroregulation in all-around recovery:Maintain stability and orient to long-term priorities

    Institute of Scientific and Technical Information of China (English)

    陈东琪

    2009-01-01

    Since last October, loose monetary and credit policies and the stimulus package have produced desired results. The economy has entered into a "V-shaped" recovery in the second quarter of this year after hitting the bottom in the first quarter, with various economic indicators rising fast, rescue missions completed and short-term objectives basically met. In this context, the next step of macro-regulation should focus on long-term objectives, speed up institutional innovation and restructuring, control the intensity, pattern and pace of short-term policy loosening and prevent inflation and wild swings in the economy so as to achieve a new round of sustained and rapid economic growth.

  13. Biogeochemical Cycling and Environmental Stability of Pu Relevant to Long-Term Stewardship of DOE Sites

    Energy Technology Data Exchange (ETDEWEB)

    Honeyman, Bruce D.; Francis, A.J.; Gillow, Jeffrey B.; Dodge, Cleveland J.; Santschi, Peter H.; Chin-Chang Hung; Diaz, Angelique; Tinnacher, Ruth; Roberts, Kimberly; Schwehr, Kathy

    2006-04-05

    The overall objective of this research is to understand the biogeochemical cycling of Pu in environments of interest to long-term DOE stewardship issues. Central to Pu cycling (transport initiation and immobilization) is the role of microorganisms. The hypothesis underlying this work is that microbial activity is the causative agent in initiating the mobilization of Pu in near-surface environments: through the transformation of Pu associated with solid phases, production of extracellular polymeric substances (EPS) carrier phases and the creation of microenvironments. Also, microbial processes are central to the immobilization of Pu species, through the metabolism of organically complexed Pu species and Pu associated with extracellular carrier phases and the creation of environments favorable for Pu transport retardation.

  14. Biogeochemical Cycling and Environmental Stability of Pu Relevant to Long-Term Stewardship of DOE Sites

    Energy Technology Data Exchange (ETDEWEB)

    Francis, Arokiasamy J.; Santschi, Peter H.; Honeyman, Bruce D.

    2005-06-01

    The overall objective of this proposed research is to understand the biogeochemical cycling of Pu in environments of interest to long-term DOE stewardship issues. Central to Pu cycling (transport initiation to immobilization) is the role of microorganisms. The hypothesis underlying this proposal is that microbial activity is the causative agent in initiating the mobilization of Pu in near-surface environments: through the transformation of Pu associated with solid phases, production of extracellular polymeric substances (EPS) carrier phases, and the creation of microenvironments. Also, microbial processes are central to the immobilization of Pu species, through the metabolism of organically complexed Pu species and Pu associated with extracellular carrier phases and the creation of environments favorable for Pu transport retardation.

  15. The stability of hydrogen evolution activity and corrosion behavior of NiCu coatings with long-term electrolysis in alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Solmaz, Ramazan; Doener, Ali; Kardas, Guelfeza [Cukurova University, Science and Letters Faculty, Chemistry Department, 01330, Balcali, Adana (Turkey)

    2009-03-15

    In this study, NiCu composite coating was electrochemically deposited on a copper electrode (Cu/NiCu) and tested for hydrogen evolution reaction (HER) in 1 M KOH solution for long-term electrolysis with the help of cathodic current-potential curves and electrochemical impedance spectroscopy (EIS) techniques. The bulk and surface composition of the coating was determined using atomic absorption spectroscopy (AAS) and energy dispersive X-ray (EDX) analysis. The surface morphology was investigated by scanning electron microscopy (SEM). The effect of electrolysis on the corrosion behavior of the Cu/NiCu electrode was also reported. It was found that the NiCu coating had a compact and porous structure with good time stability. The HER activity of the coating was stable over 120 h electrolysis and the HER mechanism was not modified during the operation. The corrosion tests showed that the corrosion resistance of the Cu/NiCu electrode changed when a cathodic current was applied to the electrolysis system. (author)

  16. Water photolysis effect on the long-term stability of a fiber optic hydrogen sensor with Pt/WO3

    Science.gov (United States)

    Zhong, Xuexiang; Yang, Minghong; Huang, Chujia; Wang, Gaopeng; Dai, Jixiang; Bai, Wei

    2016-12-01

    One of the technological challenges for hydrogen sensors is long-term stability and reliability. In this article, the UV-light irradiation was introduced into the hydrogen sensing process based on water photolysis effect of Pt/WO3. Ascribing to that, fiber optic hydrogen sensor with Pt/WO3 nanosheets as the sensing element was demonstrated with significantly improved performance of stability. Under UV irradiation, the hydrogen sensor exhibits higher sensitivity and resolution together with a smaller error range than that without UV irradiation. The enhanced performance could be attributed to the effective decomposition of water produced in the hydrogen sensing process due to the water photolysis effect of Pt/WO3. The influence of the water on stability was evaluated using experimental results, and the UV irradiation to remove water was analysed by theoretical and FT-IR spectra. This work provides new strategy of UV-light irradiation to promote the long-term stability of hydrogen sensor using Pt/WO3 as the sensing element.

  17. Long-term stability of intracortical recordings using perforated and arrayed Parylene sheath electrodes

    Science.gov (United States)

    Hara, Seth A.; Kim, Brian J.; Kuo, Jonathan T. W.; Lee, Curtis D.; Meng, Ellis; Pikov, Victor

    2016-12-01

    . This study provided support for the importance of creating a supportive biological environment around the probes to promote the long-term electrophysiological performance of flexible probes in the cerebral cortex. In particular, we demonstrated beneficial effects of the Matrigel coating and the long-term expression of Caveolin-1. Furthermore, we provided support to an idea of using an artificial acellular tissue compartment as a way to counteract the walling-off effect of the astrocytic scar formation around the probes as a means of establishing a more intimate and stable neural interface.

  18. Reprogramming suppresses premature senescence phenotypes of Werner syndrome cells and maintains chromosomal stability over long-term culture.

    Directory of Open Access Journals (Sweden)

    Akira Shimamoto

    Full Text Available Werner syndrome (WS is a premature aging disorder characterized by chromosomal instability and cancer predisposition. Mutations in WRN are responsible for the disease and cause telomere dysfunction, resulting in accelerated aging. Recent studies have revealed that cells from WS patients can be successfully reprogrammed into induced pluripotent stem cells (iPSCs. In the present study, we describe the effects of long-term culture on WS iPSCs, which acquired and maintained infinite proliferative potential for self-renewal over 2 years. After long-term cultures, WS iPSCs exhibited stable undifferentiated states and differentiation capacity, and premature upregulation of senescence-associated genes in WS cells was completely suppressed in WS iPSCs despite WRN deficiency. WS iPSCs also showed recapitulation of the phenotypes during differentiation. Furthermore, karyotype analysis indicated that WS iPSCs were stable, and half of the descendant clones had chromosomal profiles that were similar to those of parental cells. These unexpected properties might be achieved by induced expression of endogenous telomerase gene during reprogramming, which trigger telomerase reactivation leading to suppression of both replicative senescence and telomere dysfunction in WS cells. These findings demonstrated that reprogramming suppressed premature senescence phenotypes in WS cells and WS iPSCs could lead to chromosomal stability over the long term. WS iPSCs will provide opportunities to identify affected lineages in WS and to develop a new strategy for the treatment of WS.

  19. FACT - Long-term stability and observations during strong Moon light

    CERN Document Server

    Knoetig, M L; Bretz, T; Buß, J; Dorner, D; Einecke, S; Eisenacher, D; Hildebrand, D; Krähenbühl, T; Lustermann, W; Mannheim, K; Meier, K; Neise, D; Overkemping, A -K; Paravac, A; Pauss, F; Rhode, W; Ribordy, M; Steinbring, T; Temme, F; Thaele, J; Vogler, P; Walter, R; Weitzel, Q; Zänglein, M

    2013-01-01

    The First G-APD Cherenkov Telescope (FACT) is the first Cherenkov telescope equipped with a camera made of silicon photon detectors (G-APD aka. SiPM). Since October 2011, it is regularly taking data on the Canary Island of La Palma. G-APDs are ideal detectors for Cherenkov telescopes as they are robust and stable. Furthermore, the insensitivity of G-APDs towards strong ambient light allows to conduct observations during bright Moon and twilight. This gain in observation time is essential for the long-term monitoring of bright TeV blazars. During the commissioning phase, hundreds of hours of data (including data from the the Crab Nebula) were taken in order to understand the performance and sensitivity of the instrument. The data cover a wide range of observation conditions including different weather conditions, different zenith angles and different light conditions (ranging from dark night to direct full Moon). We use a new parmetrisation of the Moon light background to enhance our scheduling and to monitor ...

  20. Long-term stability of normal condition data for novelty detection

    Science.gov (United States)

    Manson, Graeme; Pierce, S. Gareth; Worden, Keith; Monnier, Thomas; Guy, Philippe; Atherton, Kathryn

    2000-06-01

    As a technique of diagnosing failure in structures and systems, the method of novelty detection shows considerable merit. The basis of the approach is simple: given measured data from normal condition of the structure, the diagnostic system builds an internal representation of the system normal condition in such a way that subsequent departures from this condition can be identified with confidence in a robust manner. The success or failure of the method is contingent on the accuracy of the description of normal condition. In many cases, the normal condition data may have quite a complex structure: for example, an aircraft may experience a wide range of ambient temperatures in the course of a single flight. Also, the operational loads experienced by the craft as a result of flight manoeuvres may have wide-ranging effects on the measured states. The object of the current paper is to explore the normal condition space for a simple benchmark monitoring system. The said system uses Lamb-wave inspection to diagnose damage in a composite plate. Both short-term and long-term experiments are carried out in order to examine the variations in normal condition as a result of run-in of the instrumentation and variations in ambient temperature. The exercise is not purely academic as the fiber-optic monitoring system is a serious candidate for a practical diagnostic system.

  1. Seed-specific expression of spider silk protein multimers causes long-term stability

    Directory of Open Access Journals (Sweden)

    Nicola eWeichert

    2016-01-01

    Full Text Available Seeds enable plants to germinate and to grow in situations of limited availability of nutrients. The stable storage of different seed proteins is a remarkable presumption for successful germination and growth. These strategies have been adapted and used in several molecular farming projects. In this study, we explore the benefits of seed-based expression to produce the high molecular weight spider silk protein FLAG using intein-based trans-splicing. Multimers larger than 460 kDa in size are routinely produced, which is above the native size of the FLAG protein. The storage of seeds for eight weeks and one year at an ambient temperature of 15°C does not influence the accumulation level. Even the extended storage time does not influence the typical pattern of multimerized bands. These results show that seeds are the method of choice for stable accumulation of products of complex transgenes and have the capability for long-term storage at moderate conditions, an important feature for the development of suitable downstream processes.

  2. Functional stability of microbial communities from long-term stressed soils to additional disturbance

    NARCIS (Netherlands)

    Tobor-Kaplon, M.A.; Bloem, J.; Ruiter, de P.C.

    2006-01-01

    Functional stability, measured in terms of resistance and resilience of soil respiration rate and bacterial growth rate, was studied in soils from field plots that have been exposed to copper contamination and low pH for more than two decades. We tested whether functional stability follows patterns

  3. Long-term Properties of Accretion Disks in X-ray Binaries II. Stability of Radiation-Driven Warping

    CERN Document Server

    Clarkson, W I; Coe, M J; Laycock, S

    2003-01-01

    A significant number of X-ray binaries are now known to exhibit long-term ``superorbital'' periodicities on timescales of $\\sim$ 10 - 100 days. Several physical mechanisms have been proposed that give rise to such periodicities, in particular warping and/or precession of the accretion disk. Recent theoretical work predicts the stability to disk warping of X-ray binaries as a function of the mass ratio, binary radius, viscosity and accretion efficiency, and here we examine the constraints that can be placed on such models by current observations. In paper I we used a dynamic power spectrum (DPS) analysis of long-term X-ray datasets (CGRO, RXTE), focusing on the remarkable, smooth variations in the superorbital period exhibited by SMC X-1. Here we use a similar DPS analysis to investigate the stability of the superorbital periodicities in the neutron star X-ray binaries Cyg X-2, LMC X-4 and Her X-1, and thereby confront stability predictions with observation. We find that the period and nature of superorbital v...

  4. Stability of soil organic matter accumulated under long-term use as a rice paddy

    Science.gov (United States)

    Nakahara, Shiko; Zou, Ping; Ando, Ho; Fu, Jianrong; Cao, Zhihong; Nakamura, Toshio; Sugiura, Yuki; Watanabe, Akira

    2016-01-01

    To understand the mechanism responsible for the enhanced accumulation of soil organic matter (SOM) under long-term use as a rice paddy, soil samples from the plow layer from 16 fields that have been used for irrigated rice production from 5 to 2000 years in the Hangzhou Bay, China, were analyzed. The humin in silt/clay particles was isolated as a representative relatively stable SOM pool, and isotopic signatures (δ13C, δ15N, and 14C concentration), 13C nuclear magnetic resonance (NMR) spectra, and biodegradability in an incubation were examined. The amounts of C and N in the bulk soil, silt/clay, and silt/clay-humin increased with increasing period of use as a rice paddy within the east and west zones, respectively. The degree of humification determined for humic acids indicated that the progression of humification did not contribute to the accumulation of C beyond 100 years. The δ15N of silt/clay-humin suggested an increase in organic N derived from chemical fertilizer or recent biological fixation with increasing amount of this fraction. The 14C concentration showed a negative correlation with the amount of silt/clay-humin C. The structural property with regard to 13C NMR spectra and biodegradability of the silt/clay-humin remained constant with the length of use as a rice paddy or 14C concentration. These results suggest that the larger C or N accumulation in the soils with a longer rice paddy history can be attributed to an enhancement in the accumulation of recently generated SOM rather than the stable accumulation of humus over the years.

  5. The Critical Choice of PEDOT: PSS Additives for Long Term Stability of Roll‐to‐Roll Processed OPVs

    DEFF Research Database (Denmark)

    Roth, Bérenger; Benatto, Gisele Alves dos Reis; Corazza, Michael

    2015-01-01

    The impact of additives mixed with poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) on the stability of organic photovoltaic modules is investigated for fully ambient roll-to-roll (R2R) processed indium tin oxide free modules. Four different PEDOT:PSS inks from two different...... on organic photovoltaic stability (ISOS). For the harsh indoor test (ISOS-L-3) only a slight difference in stability is observed between the different modules. During both ISOS-L-3 and ISOS-D-3 one new failure mode is observed as a result of tiny air inclusions in the barrier foil and a R2R method...... is identified. The data are extended in an ongoing experiment where DMSO is used as additive for long-term outdoor testing in a solar park....

  6. Long-Term Morphological and Microarchitectural Stability of Tissue-Engineered, Patient-Specific Auricles In Vivo.

    Science.gov (United States)

    Cohen, Benjamin Peter; Hooper, Rachel C; Puetzer, Jennifer L; Nordberg, Rachel; Asanbe, Ope; Hernandez, Karina A; Spector, Jason A; Bonassar, Lawrence J

    2016-03-01

    Current techniques for autologous auricular reconstruction produce substandard ear morphologies with high levels of donor-site morbidity, whereas alloplastic implants demonstrate poor biocompatibility. Tissue engineering, in combination with noninvasive digital photogrammetry and computer-assisted design/computer-aided manufacturing technology, offers an alternative method of auricular reconstruction. Using this method, patient-specific ears composed of collagen scaffolds and auricular chondrocytes have generated auricular cartilage with great fidelity following 3 months of subcutaneous implantation, however, this short time frame may not portend long-term tissue stability. We hypothesized that constructs developed using this technique would undergo continued auricular cartilage maturation without degradation during long-term (6 month) implantation. Full-sized, juvenile human ear constructs were injection molded from high-density collagen hydrogels encapsulating juvenile bovine auricular chondrocytes and implanted subcutaneously on the backs of nude rats for 6 months. Upon explantation, constructs retained overall patient morphology and displayed no evidence of tissue necrosis. Limited contraction occurred in vivo, however, no significant change in size was observed beyond 1 month. Constructs at 6 months showed distinct auricular cartilage microstructure, featuring a self-assembled perichondrial layer, a proteoglycan-rich bulk, and rounded cellular lacunae. Verhoeff's staining also revealed a developing elastin network comparable to native tissue. Biochemical measurements for DNA, glycosaminoglycan, and hydroxyproline content and mechanical properties of aggregate modulus and hydraulic permeability showed engineered tissue to be similar to native cartilage at 6 months. Patient-specific auricular constructs demonstrated long-term stability and increased cartilage tissue development during extended implantation, and offer a potential tissue-engineered solution for

  7. Long-Term Stability of Core Language Skill in Children with Contrasting Language Skills

    Science.gov (United States)

    Bornstein, Marc H.; Hahn, Chun-Shin; Putnick, Diane L.

    2016-01-01

    This 4-wave longitudinal study evaluated stability of core language skill in 421 European American and African American children, half of whom were identified as low (n = 201) and half of whom were average-to-high (n = 220) in later language skill. Structural equation modeling supported loadings of multivariate age-appropriate multisource measures…

  8. Long term stability of mandibular advancement procedures : bilateral sagittal split osteotomy versus distraction osteogenesis

    NARCIS (Netherlands)

    Baas, E. M.; Pijpe, J.; de Lange, J.

    2012-01-01

    The aim of this study was to compare the postoperative stability of the mandible after a bilateral lengthening procedure, either by bilateral sagittal split osteotomy (BSSO) or distraction osteogenesis (DO). All patients who underwent mandibular advancement surgery between March 2001 and June 2004 w

  9. Sulfur Poisoning of Ni/stabilized-zirconia Anodes – Effect on Long-Term Durability

    DEFF Research Database (Denmark)

    Hauch, Anne; Hagen, Anke; Hjelm, Johan;

    2013-01-01

    -term galvanostatic operation in internal reforming gas mixture (CH4/H2O/H2:30/60/10), with 2 ppm H2S exposure to the anode, at different current densities. The aim was not only to investigate the well-known initial performance drop associated with adsorbed sulfur in the Ni/stabilized-zirconia anodes, but also...

  10. Long-term stability in children's frontal EEG alpha asymmetry between 14-months and 83-months

    NARCIS (Netherlands)

    Müller, B.C.N.; Kuhn-Popp, N.; Meinhardt, J.; Sodian, B.; Paulus, M.A.

    2015-01-01

    In the present study, we investigated the test-retest stability of resting state alpha asymmetry in 18 children (9 male and 9 female) in a longitudinal design. Children's resting state brain activation asymmetries were assessed by means of EEG first after 14 months of age, and again a second time at

  11. Long-term stability of thujone, fenchone, and pinocamphone in vintage preban absinthe.

    Science.gov (United States)

    Lachenmeier, Dirk W; Nathan-Maister, David; Breaux, Theodore A; Kuballa, Thomas

    2009-04-01

    Research was conducted to ascertain whether analyses of vintage absinthe samples represent their original composition in the early 1900s. Absinthe stored in traditional green glass bottles and irradiated with ultraviolet light for up to 200 h exhibited unchanged composition. Samples stored in clear glass exhibited an 18% reduction in beta-thujone content and a concurrent decoloration. These experiments indicate the stability of thujone in vintage absinthes, as these were stored in green glass bottles. The preserved color of the preban absinthes subjected to analysis indicates that no significant light exposure occurred throughout the duration of storage, and therefore provides indirect proof that no loss of terpenes occurred. The stability of absinthe was further demonstrated through the reanalysis of samples from 2001-2005, which exhibited no changes in thujone content as of 2008. A previous evaluation of preban absinthe was therefore valid and not confounded by significant thujone deterioration over time.

  12. Stabilization of Neem Oil Biodiesel with Corn Silk Extract during Long-term Storage.

    Science.gov (United States)

    Ali, Rehab Farouk M; El-Anany, Ayman M

    2017-02-01

    The current study aimed to evaluate the antioxidant efficiency of different extracts of corn silk. In addition, the impact of corn silk extract on oxidative stability of neem biodiesel during storage was studied. The highest phenolics, DPPH radical scavenging and reducing power activities were recorded for methanol-water extract. The longest oxidation stability (10 h) was observed for biodiesel samples blended with 1000 ppm of corn silk extract (CSE). At the end of storage period the induction time of biodiesel samples mixed with 1000 ppm of CSE or butylated hydroxytoluene (BHT) were about 6.72 and 5.63 times as high as in biodiesel samples without antioxidants. Biodiesel samples blended with 1000 ppm of CSE had the lowest acidity at the end of storage period. Peroxide value of biodiesel samples containing 1000 ppm of CSE was about 4.28 times as low as in control sample without antioxidants.

  13. Thermal and long-term freezing stability of ivermectin residues in sheep milk

    NARCIS (Netherlands)

    Cerkvenik, V.; Doganoc, D.Z.; Skubic, V.; Beek, W.M.J.; Keukens, H.J.

    2001-01-01

    The stability of ivermectin residues in sheep milk under conditions of pasteurization (74 °C, 40 s), high pasteurization (80 °C, 1 min), and boiling (100 °C, 10 s) based on residue content (at a level of concentration of about 2 ?g/kg and 30 ?g/kg of H2B1a) and sort of ingestion (in vitro, in vivo)

  14. Long term stability of paraoxonase-1 and high-density lipoprotein in human serum

    Directory of Open Access Journals (Sweden)

    Beekhof Piet K

    2012-05-01

    Full Text Available Abstract Background Paraoxonase-1 (PON1 is an enzyme with numerous functions and receives an increasing interest in clinical and epidemiological studies. Sometimes samples are stored for longer periods at a certain temperature. Therefore the stability of PON1 activity must be checked and retained upon storage for longer periods. Results In this study the stability of PON1 activity has been tested in human serum samples during storage up to 12 months at 3 commonly used temperatures, -20°C, -70°C and −196°C. It was found that the stability of the PON1 activity is constant during 12 months of storage at −70°C and −196°C. Storage at −20°C resulted in a small but statistically significant decrease after 6 months to about 94% of its original value. Nonetheless, the rank order between the samples at T = 0 and 12 months remained the same. The same temperature dependence was found for the associated high-density lipoprotein. Conclusions It can be concluded that −70°C is the right temperature for storage to maintain the PON1 activity for at least one year. Storage at a lower temperature in liquid nitrogen (−196°C is not necessary.

  15. Long-term stability of phase-separated Half-Heusler compounds

    OpenAIRE

    Krez, Julia; Balke, Benjamin; Felser, Claudia; Hermes, Wilfried; Schwind, Markus

    2015-01-01

    Half-Heusler (HH) compounds have shown high Figure of merits up to 1.5. The key to these high thermoelectric efficiencies is an intrinsic phase separation, which occurs in multicomponent Half-Heusler compounds and leads to an significantly reduction of the thermal conductivity. For commercial applications, compatible n- and p-type materials are essential and their thermal stability under operating conditions, e.g. for an automotive up to 873 K, needs to be guaranteed. For the first time, the ...

  16. Long-term stability of sensitivity to intracortical microstimulation of somatosensory cortex

    Science.gov (United States)

    Callier, Thierri; Schluter, Erik W.; Tabot, Gregg A.; Miller, Lee E.; Tenore, Francesco V.; Bensmaia, Sliman J.

    2015-10-01

    Objective. The dexterous manipulation of objects depends heavily on somatosensory signals from the limb. The development of anthropomorphic robotic arms and of algorithms to decode intended movements from neuronal signals has stimulated the need to restore somatosensation for use in upper-limb neuroprostheses. Without touch and proprioception, patients have difficulty controlling prosthetic limbs to a level that justifies the required invasive surgery. Intracortical microstimulation (ICMS) through chronically implanted electrode arrays has the potential to provide rich and intuitive sensory feedback. This approach to sensory restoration requires, however, that the evoked sensations remain stable over time. Approach. To investigate the stability of ICMS-evoked sensations, we measured the ability of non-human primates to detect ICMS over experimental sessions that spanned years. Main results. We found that the performance of the animals remained highly stable over time, even when they were tested with electrodes that had experienced extensive stimulation. Significance. Given the stability of the sensations that it evokes, ICMS may thus be a viable approach for sensory restoration.

  17. Urease immobilized polymer hydrogel: Long-term stability and enhancement of enzymatic activity.

    Science.gov (United States)

    Kutcherlapati, S N Raju; Yeole, Niranjan; Jana, Tushar

    2016-02-01

    A method has been developed in which an enzyme namely urease was immobilized inside hydrogel matrix to study the stability and enzymatic activity in room temperature (∼27-30°C). This urease coupled hydrogel (UCG) was obtained by amine-acid coupling reaction and this procedure is such that it ensured the wider opening of mobile flap of enzyme active site. A systematic comparison of urea-urease assay and the detailed kinetic data clearly revealed that the urease shows activity for more than a month when stored at ∼27-30°C in case of UCG whereas it becomes inactive in case of free urease (enzyme in buffer solution). The aqueous microenvironment inside the hydrogel, unusual morphological features and thermal behaviour were believed to be the reasons for unexpected behaviour. UCG displayed enzyme activity at basic pH and up to 60°C. UCG showed significant enhancement in activity against thermal degradation compared to free urease. In summary, this method is a suitable process to stabilize the biomacromolecules in standard room temperature for many practical uses.

  18. Long-term Stability of Planets in the α Centauri System

    Science.gov (United States)

    Quarles, B.; Lissauer, Jack J.

    2016-05-01

    We evaluate the extent of the regions within the α Centauri AB star system where small planets are able to orbit for billion-year timescales, and we calculate the positions on the sky plane where planets on stable orbits about either stellar component may appear. We confirm the qualitative results of Wiegert and Holman (AJ 113, 1445, 1997) regarding the approximate size of the regions of stable orbits, which are larger for retrograde orbits relative to the binary than for prograde orbits. Additionally, we find that mean motion resonances with the binary orbit leave an imprint on the limits of orbital stability, and the effects of the Lidov-Kozai mechanism are also readily apparent.

  19. Long-Term Stability of Planets in the $\\alpha$ Centauri System

    CERN Document Server

    Quarles, Billy

    2016-01-01

    We evaluate the extent of the regions within the $\\alpha$ Centauri AB star system where small planets are able to orbit for billion-year timescales, and we calculate the positions on the sky plane where planets on stable orbits about either stellar component may appear. We confirm the qualitative results of Wiegert and Holman (AJ 113, 1445, 1997) regarding the approximate size of the regions of stable orbits, which are larger for retrograde orbits relative to the binary than for prograde orbits. Additionally, we find that mean motion resonances with the binary orbit leave an imprint on the limits of orbital stability, and the effects of the Lidov-Kozai mechanism are also readily apparent.

  20. Mathematical model of thermal shields for long-term stability optical resonators

    CERN Document Server

    Sanjuan, Josep; Braxmaier, Claus

    2015-01-01

    Modern experiments aiming at tests of fundamental physics, like measuring gravitational waves or testing Lorentz Invariance with unprecedented accuracy, require thermal environments that are highly stable over long times. To achieve such a stability, the experiment including typically an optical resonator is nested in a thermal enclosure, which passively attenuates external temperature fluctuations to acceptable levels. These thermal shields are usually designed using tedious numerical simulations or with simple analytical models. In this paper, we propose an accurate analytical method to estimate the performance of passive thermal shields in the frequency domain, which allows for fast evaluation and optimization. The model analysis has also unveil interesting properties of the shields, such as dips in the transfer function for some frequencies under certain combinations of materials and geometries. We validate the results by comparing them to numerical simulations performed with commercial software based on ...

  1. Long-Term Stability of Planets in the Alpha Centauri System

    Science.gov (United States)

    Lissauer, Jack J.; Quarles, Billy L.

    2016-10-01

    The alpha Centauri star system contains the Solar Systems closest stellar neighbors. If an earthlike planet is present in the system, it could in principle be detected using a small space-based telescope (Belikov et al. 2105, Proc. SPIE 9605, 960518). The alpha Centauri system is billions of years old, so planets are only expected to be found in regions where their orbits are long-lived. We evaluate the extent of the regions within the alpha Centauri AB star system where small planets are able to orbit for billion-year timescales, and we map the positions in the sky plane where planets on stable orbits about either stellar component may appear. We confirm the qualitative results of Wiegert & Holman (Astron. J. 113, 1445, 1997) regarding the approximate size of the regions of stable orbits of a single planet, which are larger for retrograde orbits relative to the binary than for prograde orbits. Additionally, we find that mean motion resonances with the binary orbit leave an imprint on the limits of orbital stability, and the effects of the Lidov-Kozai mechanism are also readily apparent. Because the binary companion induces a forced eccentricity upon the orbits of planets in orbit around either star, appropriately-phased circumstellar orbits with small initial eccentricities are stable to somewhat larger initial semimajor axes than are initially circular orbits and the initial mean anomaly of planets is a factor in determining stability. Our results can guide observers designing instrumentation and search strategies to attempt to discover planets orbiting the nearest sunlike stars.

  2. Long-Term Stability of Underground Operated CZT Detectors Based on the Analysis of Intrinsic $^{113}$Cd \\beta$^{-}$-Decay

    CERN Document Server

    Ebert, J; Gehre, D; Hagner, C; Heidrich, N; Klingenberg, R; Kroeninger, K; Nitsch, C; Oldorf, C; Quante, T; Rajek, S; Rebber, H; Rohatsch, K; Tebruegge, J; Temminghoff, R; Theinert, R; Timm, J; Wonsak, B; Zatschler, S; Zuber, K

    2015-01-01

    The COBRA collaboration operates a demonstrator setup at the underground facility LNGS (Laboratori Nazionali del Gran Sasso, located in Italy) to prove the technological capabilities of this concept for the search for neutrinoless double beta-decay. The setup consists of 64 $(1\\times\\!1\\times\\!1)$ cm$^{3}$ CZT detectors in CPG configuration. One purpose of this demonstrator is to test if reliable long-term operation of CZT-CPG detectors in such a setup is possible. The demonstrator has been operated under ultra low-background conditions since more than three years and collected data corresponding to an exposure of 218 kg$\\cdot$days. The presented study focuses on the long-term stability of CZT detectors by analyzing the intrinsic, fourfold forbidden non-unique $^{113}$Cd single beta-decay. It can be shown that CZT detectors can be operated stably for long periods of time and that the $^{113}$Cd single beta-decay can be used as an internal monitor of the detector performance during the runtime of the experimen...

  3. Using the fluorescence red edge effect to assess the long-term stability of lyophilized protein formulations.

    Science.gov (United States)

    Qian, Ken K; Grobelny, Pawel J; Tyagi, Madhusudan; Cicerone, Marcus T

    2015-04-06

    Nanosecond relaxation processes in sugar matrices are causally linked through diffusional processes to protein stability in lyophilized formulations. Long-term protein degradation rates track mean-squared displacement (⟨u(2)⟩) of hydrogen atoms in sugar glasses, a parameter describing dynamics on a time scale of picoseconds to nanoseconds. However, measurements of ⟨u(2)⟩ are usually performed by neutron scattering, which is not conducive to rapid formulation screening in early development. Here, we present a benchtop technique to derive a ⟨u(2)⟩ surrogate based on the fluorescence red edge effect. Glycerol, lyophilized trehalose, and lyophilized sucrose were used as model systems. Samples containing 10(-6) mole fraction of rhodamine 6G, a fluorophore, were excited at either 532 nm (main peak) or 566 nm (red edge), and the ⟨u(2)⟩ surrogate was determined based the corresponding Stokes shifts. Results showed reasonable agreement between ⟨u(2)⟩ from neutron scattering and the surrogate from fluorescence, although deviations were observed at very low temperatures. We discuss the sources of the deviations and suggest technique improvements to ameliorate these. We expect that this method will be a valuable tool to evaluate lyophilized sugar matrices with respect to their ability to protect proteins from diffusion-limited degradation processes during long-term storage. Additionally, the method may have broader applications in amorphous pharmaceutical solids.

  4. Occlusal stabilization splint for patients with temporomandibular disorders: Meta-analysis of short and long term effects

    Science.gov (United States)

    Kuzmanovic Pficer, Jovana; Dodic, Slobodan; Lazic, Vojkan; Trajkovic, Goran

    2017-01-01

    Background Psychological discomfort, physical disability and functional limitations of the orofacial system have a major impact on everyday life of patients with temporomandibular disorders (TMDs). In this study we sought to determine short and long term effects of stabilization splint (SS) in treatment of TMDs, and to identify factors influencing its efficacy. Methods MEDLINE, Web of Science and EMBASE were searched for randomized controlled trials (RCTs) comparing SS to: non-occluding splint, occlusal oral appliances, physiotherapy, behavioral therapy, counseling and no treatment. Random effects method was used to summarize outcomes. The effect estimates were expressed as odds ratio (OR) or standardized mean difference (SMD) with 95% confidence interval. Subgroup analyses were carried out according to the use of Research Diagnostic Criteria (RDC/TMD) and TMDs origin. Strength of evidence was assessed by GRADE. Meta-regression was applied. Results Thirty three eligible RCTs were included in meta-analysis. In short term, SS presented positive overall effect on pain reduction (OR 2.08; p = 0.01) and pain intensity (SMD -0.33; p = 0.02). Subgroup analyses confirmed SS effect in studies used RDC/TMD and revealed its effect in patients with TMDs of muscular origin. Important decrease of muscle tenderness (OR 1.97; p = 0.03) and improvement of mouth opening (SMD -0.30; p = 0.04) were found. SS in comparison to oral appliances showed no difference (OR 0.74; p = 0.24). Meta-regression identified continuous use of SS during the day as a factor influencing efficacy (p = 0.01). Long term results showed no difference in observed outcomes between groups. Low quality of evidence was found for primary outcomes. Conclusion SS presented short term benefit for patients with TMDs. In long term follow up, the effect is equalized with other therapeutic modalities. Further studies based on appropriate use of standardized criteria for patient recruitment and outcomes under assessment

  5. Long-Term Stability of Planets in the Alpha Centauri System

    Science.gov (United States)

    Lissauer, Jack; Quarles, Billy

    2015-01-01

    The alpha Centauri system is billions of years old, so planets are only expected to be found in regions where their orbits are long-lived. We evaluate the extent of the regions within the alpha Centauri AB star system where small planets are able to orbit for billion-year timescales, and we map the positions in the sky plane where planets on stable orbits about either stellar component may appear. We confirm the qualitative results of Wiegert & Holman (Astron. J. 113, 1445, 1997) regarding the approximate size of the regions of stable orbits of a single planet, which are larger for retrograde orbits relative to the binary than for pro-grade orbits. Additionally, we find that mean motion resonances with the binary orbit leave an imprint on the limits of orbital stability, and the effects of the Lidov-Kozai mechanism are also readily apparent. Overall, orbits of a single planet in the habitable zones near the plane of the binary are stable, whereas high-inclination orbits are short-lived. However, even well within regions where single planets are stable, multiple planet systems must be significantly more widely-spaced than they need to be around an isolated star in order to be long-lived.

  6. Long-term stability of hydrogen isotope ratios in hydrated volcanic glass

    Science.gov (United States)

    Cassel, Elizabeth J.; Breecker, Daniel O.

    2017-03-01

    The advancement of conceptual and numerical geodynamic models necessitates quantitative, orogen-scale paleoelevation data. Felsic volcanic glasses, which record the hydrogen isotope compositions (δD) of meteoric water shortly after deposition, provide several advantages as a paleoelevation proxy. Questions remain, however, about the reliability of this relatively new proxy, including the effect of hydrofluoric (HF) acid abrasion in the preparation of glass shards for hydrogen isotope analysis and the stability of hydrogen isotope ratios in hydrated glass shards over geologic time (106-107 years). HF acid abrasion of natural ancient glass shards results in systematic shifts in glass δD values away from modern water δD values. To evaluate the effectiveness of HF acid abrasion, we treated 70-150 μm glass shards separated from various natural tephras with deuterium-labeled water (DLW; δD = +18,205‰) for up to 400 days. For all glasses, this treatment resulted in elevated δD values in comparison to untreated samples. HF acid abrasion after DLW exposure, however, removed this effect and restored glass shards to their original untreated δD values in samples older than 104 years. HF acid abrasion removes hydrous alteration precipitates at the glass surface without measurably changing the δD values of the underlying hydrated glass, regardless of abrasion duration or glass composition. Additionally, 45-34 Ma glasses record δD values that directly reflect their depositional environments as determined by stratigraphy: glasses from tuffs deposited in demonstrably evaporative lacustrine environments have relatively high δD values compared to glasses from contemporaneous tuffs deposited in nearby fluvial environments, which have much lower δD values. The preservation of δD values that systematically vary with original depositional environment, despite >30 Myr of post-hydration exposure to the same meteoric water, indicates that these volcanic glasses resisted

  7. Influence of Previous Crop on Durum Wheat Yield and Yield Stability in a Long-term Experiment

    Directory of Open Access Journals (Sweden)

    Anna Maria Stellacci

    2011-02-01

    Full Text Available Long-term experiments are leading indicators of sustainability and serve as an early warning system to detect problems that may compromise future productivity. So the stability of yield is an important parameter to be considered when judging the value of a cropping system relative to others. In a long-term rotation experiment set up in 1972 the influence of different crop sequences on the yields and on yield stability of durum wheat (Triticum durum Desf. was studied. The complete field experiment is a split-split plot in a randomized complete block design with two replications; the whole experiment considers three crop sequences: 1 three-year crop rotation: sugar-beet, wheat + catch crop, wheat; 2 one-year crop rotation: wheat + catch crop; 3 wheat continuous crop; the split treatments are two different crop residue managements; the split-split plot treatments are 18 different fertilization formulas. Each phase of every crop rotation occurred every year. In this paper only one crop residue management and only one fertilization treatment have been analized. Wheat crops in different rotations are coded as follows: F1: wheat after sugar-beet in three-year crop rotation; F2: wheat after wheat in three-year crop rotation; Fc+i: wheat in wheat + catch crop rotation; Fc: continuous wheat. The following two variables were analysed: grain yield and hectolitre weight. Repeated measures analyses of variance and stability analyses have been perfomed for the two variables. The stability analysis was conducted using: three variance methods, namely the coefficient of variability of Francis and Kannenberg, the ecovalence index of Wricke and the stability variance index of Shukla; the regression method of Eberhart and Russell; a method, proposed by Piepho, that computes the probability of one system outperforming another system. It has turned out that each of the stability methods used has enriched of information the simple variance analysis. The Piepho

  8. Long-Term Charge/Discharge Cycling Stability of MnO2 Aqueous Supercapacitor under Positive Polarization

    KAUST Repository

    Ataherian, Fatemeh

    2011-01-01

    The long-term charge/discharge cycling stability of MnO 2 electrode under positive polarization in aqueous KCl electrolyte has been studied over different potential windows spanning from the open circuit potential to varied higher-end potential limited by O 2 evolution. Cycling up to 1.2 V (vs Ag/AgCl (aq)) causes partial (35) capacitance fading to a plateau value within the initial cycles, accompanied by morphological reconstruction, reduction of surface Mn ions and oxygen evolution. The surface Mn-ion reduction has been attributed to a two-step oxidation-reduction mechanism involving OH oxidation in electrolyte, based on electrochemical analysis. When cycling potential extends to 1.4 V, extensive oxygen evolution takes place. The combination of surface passivation of current collector and extensive gas bubbling, which deteriorates electrical contact among the constituent particles within the electrode, results in further monotonic capacitance reduction. © 2011 The Electrochemical Society.

  9. Long term stability and reproducibility of magnetic colloids are key issues for steady values of Specific Power Absorption through time

    CERN Document Server

    Sanz, B; Cassinelli, N; Ibarra, M R; Goya, G F

    2016-01-01

    Virtually all clinical applications of magnetic nanoparticles (MNPs) require the formulation of biocompatible, water-based magnetic colloids. For magnetic hyperthermia, the requirements also include a high colloidal stability against precipitation and agglomeration of the constituent MNPs, in order to keep the heating efficiency of the ferrofluid in the long term. The specific power absorption (SPA) of single-domain MNPs depends critically on the average particle size and size distribution width, therefore first-rate reproducibility among different batches regarding these parameters are also needed. We have studied the evolution of the SPA of highly reproducible and stable water-based colloid composed of polymer coated $Fe_{3}O_{4}$ magnetic nanoparticles. By measuring the specific power absorption (SPA) values along one year as a function of field amplitude and frequencies ($H \\leq 24 kA/m$; $260 \\leq f \\leq 830 kHz$), we demonstrated that SPA in these samples can be made reproducible between successive synt...

  10. Long-term dispersion stability and adhesion promotion of aqueous Cu nano-ink for flexible printed electronics.

    Science.gov (United States)

    Seo, Yeong-Hui; Jeong, Sunho; Jo, Yejin; Choi, Youngmin; Ryu, Beyong-Hwan; Han, Gayoung; Lee, Minsu

    2013-08-01

    Aqueous Cu nanoparticles are synthesized using a reducing agent and surface capping molecule which prevents the interparticular agglomeration and surface oxidation. Aqueous conductive nano ink is prepared using the resulting Cu nanoparticles and conductive Cu layers are prepared via a wet coating process. The conductive Cu layers, metalized by annealing at 300 degrees C under vacuum atmosphere, exhibit excellent electrical resistivity, showing values as low as 12 microomega cm. The long-term dispersion stability for three months is monitored through an investigation on the rheological behavior of the conductive nano ink and the resistivity variation of the conductive Cu layer. The adhesion property of the conductive Cu layer is dramatically improved when using a primer-treated polyimide film, whereas the conductive Cu layer completely peels off on a pristine polyimide film. The epoxy-contained primer plays a critical role as an intermediary between the aqueous Cu nano ink and the polyimide film.

  11. A CSTR-hollow-fiber system for continuous hydrolysis of proteins. Factors affecting long-term stability of the reactor.

    Science.gov (United States)

    Deeslie, W D; Cheryan, M

    1982-01-01

    Factors affecting the long-term operational stability of a CSTR-hollow-fiber reactor for continuous hydrolysis of proteins were studied. The activity declined in a stepwise manner during a run. Declining from 92% conversion to 60% conversion in about ten hours at a space time of four minutes. Initial decay appears to be due to leakage of small active fragments of the enzyme mixture (Pronase) through the membrane, and later decay due to thermal degradation and loss of activators such as calcium through the membrane. The rate of buildup of unconverted substrate in the reaction vessel was controlled by operational variables, but did not appear to affect the reactor output or the operation of the reactor. The decay of the reactor could be partially compensated for by appropriate manipulation of the space-time variables.

  12. Long-term stability of CdSe/CdZnS quantum dot encapsulated in a multi-lamellar microcapsule

    Science.gov (United States)

    Park, Sang-Yul; Kim, Hyo-Sun; Yoo, Jeseung; Kwon, Suyong; Shin, Tae Joo; Kim, Kyungnam; Jeong, Sohee; Seo, Young-Soo

    2015-07-01

    We developed a novel and easy encapsulation method for quantum dots (QDs) using a partially oxidized semi-crystalline polymeric material which forms a micron-sized granule with a multi-lamellar structure from a dilute solution. The QDs were highly dispersed in the granule in such a way that they were adsorbed on the lamella with ˜12 nm spacing followed by lamellar stacking. The QDs were heavily loaded into the granule to 16.7 wt% without aggregation, a process which took only a few minutes. We found that the quantum yield of the QDs was not degraded after the encapsulation. The encapsulated QD-silicone composite exhibited excellent long-term photo- and thermal stability with its initial photoluminescence intensity maintained after blue LED light radiation for 67 days and storage at 85 °C and 85% relative humidity for 119 days.

  13. Freeze-dried nifedipine-lipid nanoparticles with long-term nano-dispersion stability after reconstitution.

    Science.gov (United States)

    Ohshima, Hiroyuki; Miyagishima, Atsuo; Kurita, Takurou; Makino, Yuji; Iwao, Yasunori; Sonobe, Takashi; Itai, Shigeru

    2009-07-30

    Nifedipine (NI) is a poorly water-soluble drug and its oral bioavailability is very low. To improve the water solubility, NI-lipid nanoparticle suspensions were prepared by a combination of co-grinding by a roll mill and high-pressure homogenization without any organic solvent. The mean particle size and zeta potential of the NI-lipid nanoparticle suspensions were about 52.6 nm and -61.8 mV, respectively, and each parameter remained extremely constant during a period of 4 months under 6 degrees C and dark conditions, suggesting that the negative charge of the phospholipid, dipalmitoyl phosphatidylglycerol, is very effective in preventing coagulation of the particles. In order to assure the nano-order particle size of the suspensions in view of long-term stability, a freeze-drying technique was applied to the NI-lipid nanoparticle suspensions. The mean particle size of freeze-dried NI-lipid nanoparticles after reconstitution was significantly increased in comparison to that of the preparations before freeze-drying. It was found, however, that the addition of sugars (glucose, fructose, maltose or sucrose) to the suspensions before freeze-drying inhibited the aggregation of nanoparticles, suggesting that the long-term stability storage of freeze-dried NI-lipid nanoparticles after reconstitution would be overcome. In addition, freeze-dried nanoparticles with 100mg sugar (glucose, fructose, maltose or sucrose) showed excellent solubility (>80%), whereas without sugar, as a control, showed low solubility (coagulation of NI nanoparticle suspensions, and reproduce the nanoparticle dispersion after reconstitution; and remarkably increase the apparent solubility of nifedipine.

  14. Wheat Grain Yield and Yield Stability in a Long-Term Fertilization Experiment on the Loess Plateau

    Institute of Scientific and Technical Information of China (English)

    HAO Ming-De; FAN Jun; WANG Quan-Jiu; DANG Ting-Hui; GUO Sheng-Li; WANG Ji-Jun

    2007-01-01

    To provide a scientific basis for sustainable land management,a 20-year fertility experiment Was conducted in Changwu County,Shaanxi Province,China to investigate the effects of long-term application of chemical fertilizers on wheat grain yield and yield stability on the Loess Plateau using regression and stability analysis.The experiment consisted of 17fertilizer treatments.containing the combinations of different N and P levels,with three replications arranged in a randomized complete block design.Nitrogen fertilizer was applied as urea,and P was applied as calcium superphosphate.Fertilizer rates had a large effect on the response of wheat yield to fertilization.Phosphorus,combined with N,increased yield significantly(P≤0.01).In the unfertilized control and the N or P sole application treatments,wheat yield had a declining trend although it was not statistically significant.Stability analysis combined with the trend analysis indicated that integrated use of fertilizer N and P was better than their sole application in increasing and sustaining the productivity of rainfed winter wheat.

  15. Long Term Quadrotor Stabilization

    Science.gov (United States)

    2011-03-01

    solutions since they offer greater mobility in these environments than fixed wing UAVs or unmanned ground vehicles. Quadrotors were selected over more...Technology ANT Advanced Navigation Techonology BEC Battery Eliminator Circuit DCM Direction Cosine Matrix ESC Electronic Speed Controller FPGA Field...degree of mobility . As a result, hovering unmanned air vehicles (UAVs) have been selected as the vehicles of choice in these environments. It is also

  16. Enhanced stability of multilayer graphene-supported catalysts for polymer electrolyte membrane fuel cell cathodes

    Science.gov (United States)

    Marinkas, A.; Hempelmann, R.; Heinzel, A.; Peinecke, V.; Radev, I.; Natter, H.

    2015-11-01

    One of the biggest challenges in the field of polymer electrolyte membrane fuel cells (PEMFC) is to enhance the lifetime and the long-term stability of PEMFC electrodes, especially of cathodes, furthermore, to reduce their platinum loading, which could lead to a cost reduction for efficient PEMFCs. These demands could be achieved with a new catalyst support architecture consisting of a composite of carbon structures with significant different morphologies. A highly porous cathode catalyst support layer is prepared by addition of various carbon types (carbon black particles, multi-walled carbon nanotubes (MWCNT)) to multilayer graphene (MLG). The reported optimized cathodes shows extremely high durability and similar performance to commercial standard cathodes but with 89% lower Pt loading. The accelerated aging protocol (AAP) on the membrane electrode assemblies (MEA) shows that the presence of MLG increases drastically the durability and the Pt-extended electrochemical surface area (ECSA). In fact, after the AAP slightly enhanced performance can be observed for the MLG-containing cathodes instead of a performance loss, which is typical for the commercial carbon-based cathodes. Furthermore, the presence of MLG drastically decreases the ECSA loss rate. The MLG-containing cathodes show up to 6.8 times higher mass-normalized Pt-extended ECSA compared to the commercial standard systems.

  17. Atomic-Scale Origin of Long-Term Stability and High Performance of p-GaN Nanowire Arrays for Photocatalytic Overall Pure Water Splitting.

    Science.gov (United States)

    Kibria, Md Golam; Qiao, Ruimin; Yang, Wanli; Boukahil, Idris; Kong, Xianghua; Chowdhury, Faqrul Alam; Trudeau, Michel L; Ji, Wei; Guo, Hong; Himpsel, F J; Vayssieres, Lionel; Mi, Zetian

    2016-10-01

    The atomic-scale origin of the unusually high performance and long-term stability of wurtzite p-GaN oriented nanowire arrays is revealed. Nitrogen termination of both the polar (0001¯) top face and the nonpolar (101¯0) side faces of the nanowires is essential for long-term stability and high efficiency. Such a distinct atomic configuration ensures not only stability against (photo) oxidation in air and in water/electrolyte but, as importantly, also provides the necessary overall reverse crystal polarization needed for efficient hole extraction in p-GaN.

  18. Long-term leaching behavior of phenol in cement/activated-carbon solidified/stabilized hazardous waste.

    Science.gov (United States)

    Liu, Jianguo; Nie, Xiaoqin; Zeng, Xianwei; Su, Zhaoji

    2013-01-30

    The long-term leaching behavior of phenol in solidified/stabilized (S/S) hazardous wastes cured for 28 d with different amounts of activated carbon (AC) was investigated using synthetic inorganic acid (H(2)SO(4):HNO(3) = 2:1, pH = 3.2), acetic acid buffer (HAc/NaAc, pH = 4.93), and deionized water as leachants to simulate the leaching of phenol in three exposure scenarios: acid-precipitation, co-disposal, and neutral-precipitation. Phenol immobilization was enhanced by AC adsorption and impaired by the growth of micropores with increasing amount of AC; thus the optimal added amount of AC to be to added S/S wastes was 2%. The leaching behavior of phenol in co-disposal scenario was unpredictable due to inadequate ionization of HAc in the HAc-NaAc buffer solution. The findings indicated that S/S products should be disposed of in hazardous waste landfills rather than municipal solid waste landfills.

  19. Field Supervisory Test of DREB-Transgenic Populus: Salt Tolerance, Long-Term Gene Stability and Horizontal Gene Transfer

    Directory of Open Access Journals (Sweden)

    Nan Lu

    2014-05-01

    Full Text Available Improving saline resistance may be useful for reducing environmental susceptibility and improving yields in poplar plantations. However, the instability of genetically engineered traits and gene transfer reduce their usefulness and commercial value. To investigate whether the foreign gene is still present in the genome of receptor plants after seven years (i.e., long-term foreign gene stability and gene transfer, we randomly analyzed ten field-grown transgenic hybrid Populus ((Populus tomentosa × Populus bolleana × P. tomentosa carrying the DREB1 gene from Atriplex hortensis. The results of PCR and tissue culture experiments showed that AhDREB1 was present in the transgenic trees and was still expressed. However, the transcriptional expression level had decreased compared with that four years earlier. The PCR results also indicated no foreign gene in the genomic DNA of microorganisms in the soil near the transgenic poplars, indicating that no significant gene transfer had occurred from the transgenic poplars to the microorganisms at seven years after planting.

  20. Characteristic microbial community of a dry thermophilic methanogenic digester: its long-term stability and change with feeding.

    Science.gov (United States)

    Tang, Yue-Qin; Ji, Pan; Hayashi, Junpei; Koike, Yoji; Wu, Xiao-Lei; Kida, Kenji

    2011-09-01

    Thermophilic dry anaerobic digestion of sludge for cellulose methanization was acclimated at 53 °C for nearly 5 years using a waste paper-based medium. The stability of the microbial community structure and the microbial community responsible for the cellulose methanization were studied by 16S rRNA gene-based clone library analysis. The microbial community structure remained stable during the long-term acclimation period. Hydrogenotrophic methanogens dominated in methanogens and Methanothermobacter, Methanobacterium, Methanoculleus, and Methanosarcina were responsible for the methane production. Bacteria showed relatively high diversity and distributed mainly in the phyla Firmicutes, Bacteroidetes, and Synergistetes. Ninety percent of operational taxonomic units (OTUs) were affiliated with the phylum Firmicutes, indicating the crucial roles of this phylum in the digestion. Relatives of Clostridium stercorarium, Clostridium thermocellum, and Halocella cellulosilytica were dominant cellulose degraders. The acclimated stable sludge was used to treat garbage stillage discharged from a fuel ethanol production process, and the shift of microbial communities with the change of feed was analyzed. Both archaeal and bacterial communities had obviously changed: Methanoculleus spp. and Methanothermobacter spp. and the protein- and fatty acid-degrading bacteria became dominant. Accumulation of ammonia as well as volatile fatty acids led to the inhibition of microbial activity and finally resulted in the deterioration of methane fermentation of the garbage stillage.

  1. A survey of short-term and long-term stability of tube parameters in a mammography unit

    Directory of Open Access Journals (Sweden)

    Praskalo Jovica Ž.

    2014-01-01

    Full Text Available In order to set up a successful mammography screening program in the Republic of Srpska, a Siemens Mammomat 1000 X-ray machine was selected for analysis as the said mammography system is widely used in clinical practice. The variations in tube parameters (specific air kerma, high-voltage accuracy and reproducibility, linearity between exposure and dose exposure time were monitored over a five-year period, from 2008 to 2012. In addition, due to observed daily fluctuations for chosen parameters, a series of measurements were performed three times a day within a single-month period (mainly October 2012. The goal of such an experimental set up is to assess short-term and long-term stability of tube parameters in the given mammography unit and to make a comparison between them. The present paper shows how an early detection of significant parameter fluctuations can help eliminate irregularities and optimize the performance of mammography systems. [Projekat Ministarstva nauke Republike Srbije, br. 171007

  2. Chiral HPLC versus chiral SFC: evaluation of long-term stability and selectivity of Chiralcel OD using various eluents.

    Science.gov (United States)

    Lynam, K G; Nicolas, E C

    1993-01-01

    The long-term stability of Chiralcel OD columns under varying HPLC and SFC conditions was evaluated. Two new columns from the same supplier lot were procured, and one was installed in an HPLC system, and the other was installed in an SFC system. Enantiomeric mixtures of trans-stilbene oxide and carbobenzyloxy phenylalaninol were repeatedly injected in both systems over several days. For HPLC, hexane was the primary solvent used, along with IPA, EtOH, MeOH/IPA, or EtOH/TFA modifier. Carbon dioxide was the primary SFC solvent, together with the similar modifiers as the HPLC. Column performance was monitored by measuring resolution, theoretical plate number, and alpha between enantiomeric peaks. It was observed that, when the eluent strengths were adjusted to provide comparable retention times, the Chiralcel OD gave superior enantiomeric resolution when used in the SFC than the HPLC. Equilibration in between solvents was faster with SFC. The columns were demonstrated to be quite stable in both systems.

  3. Long term response stability of a well-type ionization chamber used in calibration of high dose rate brachytherapy sources

    Directory of Open Access Journals (Sweden)

    Vandana S

    2010-01-01

    Full Text Available Well-type ionization chamber is often used to measure strength of brachytherapy sources. This study aims to check long term response stability of High Dose Rate (HDR -1000 Plus well-type ionization chamber in terms of reference air kerma rate (RAKR of a reference 137 Cs brachytherapy source and recommend an optimum frequency of recalibration. An HDR-1000 Plus well-type ionization chamber, a reference 137 Cs brachytherapy source (CDCSJ5, and a MAX-4000 electrometer were used in this study. The HDR-1000 Plus well-type chamber was calibrated in terms of reference air kerma rate by the Standards Laboratory of the International Atomic Energy Agency (IAEA, Vienna. The response of the chamber was verified at regular intervals over a period of eight years using the reference 137 Cs source. All required correction factors were applied in the calculation of the RAKR of the 137 Cs source. This study reveals that the response of the HDR-1000 Plus well-type chamber was well within ±0.5% for about three years after calibration/recalibration. However, it shows deviations larger than ±0.5% after three years of calibration/recalibration and the maximum variation in response of the chamber during an eight year period was 1.71%. The optimum frequency of recalibration of a high dose rate well-type chamber should be three years.

  4. Long term response stability of a well-type ionization chamber used in calibration of high dose rate brachytherapy sources.

    Science.gov (United States)

    Vandana, S; Sharma, S D

    2010-04-01

    Well-type ionization chamber is often used to measure strength of brachytherapy sources. This study aims to check long term response stability of High Dose Rate (HDR)-1000 Plus well-type ionization chamber in terms of reference air kerma rate (RAKR) of a reference (137)Cs brachytherapy source and recommend an optimum frequency of recalibration. An HDR-1000 Plus well-type ionization chamber, a reference (137)Cs brachytherapy source (CDCSJ5), and a MAX-4000 electrometer were used in this study. The HDR-1000 Plus well-type chamber was calibrated in terms of reference air kerma rate by the Standards Laboratory of the International Atomic Energy Agency (IAEA), Vienna. The response of the chamber was verified at regular intervals over a period of eight years using the reference (137)Cs source. All required correction factors were applied in the calculation of the RAKR of the (137)Cs source. This study reveals that the response of the HDR-1000 Plus well-type chamber was well within +/-0.5% for about three years after calibration/recalibration. However, it shows deviations larger than +/-0.5% after three years of calibration/recalibration and the maximum variation in response of the chamber during an eight year period was 1.71%. The optimum frequency of recalibration of a high dose rate well-type chamber should be three years.

  5. Long-term frequency and amplitude stability of a solid-nitrogen-cooled, continuous wave THz quantum cascade laser

    Science.gov (United States)

    Danylov, Andriy A.; Waldman, Jerry; Light, Alexander R.; Goyette, Thomas M.; Giles, Robert H.; Qian, Xifeng; Chandrayan, Neelima; Goodhue, William D.; Nixon, William E.

    2012-02-01

    Operational temperature increase of CW THz QCLs to 77 K has enabled us to employ solid nitrogen (SN2) as the cryogen. A roughing pump was used to solidify liquid nitrogen and when the residual vapor pressure in the nitrogen reservoir reached the pumping system's minimum pressure the temperature equilibrated and remained constant until all the nitrogen sublimated. The hold time compared to liquid helium has thereby increased approximately 70-fold, and at a greatly reduced cost. The milliwatt CW QCL was at a temperature of approximately 60 K, dissipating 5 W of electrical power. To measure the long-term frequency, current, and temperature stability, we heterodyned the free-running 2.31 THz QCL with a CO2 pumped far-infrared gas laser line in methanol (2.314 THz) in a corner-cube Schottky diode and recorded the IF frequency, current and temperature. Under these conditions the performance characteristics of the QCL, which will be reported, exceeded that of a device mounted in a mechanical cryocooler.

  6. Long-term Stability of Vancomycin Hydrochloride in Glucose 5% Polyolefin Bags: The Brand Name Versus a Generic Product.

    Science.gov (United States)

    Huvelle, Sophie; Godet, Marie; Hecq, Jean-Daniel; Gillet, Patricia; Jamart, Jacques; Galanti, Laurence M

    2016-01-01

    The objectives of this study were to determine if the preparation of vancomycin hydrochloride in advance of infusion could improve the quality of the drug, time management of drug delivery, cost savings of drug delivery, and to investigate the long-term stability of vancomycin hydrochloride (brand name Vancocin®) infusion in glucose 5% polyolefin bags versus the generic (Vancomycine®) at 5°C ± 3°C. Five bags of each infusion 1 g/100 mL vancomycin hydrochloride in 5% glucose (Vancocin ® and Vancomycine®) were stored up to 57 days at 5°C ± 3°C. A visual inspection and pH measurement were performed periodically during the storage, and the concentrations were measured by high-performance liquid chromatography-diode array detection. No color change or precipitation in the solution was observed throughout the study period. As recommended by the U.S. Food and Drug Administration, the lower confidence limit at 95% of the concentration for the solutions remained superior to 90% of the initial concentration up to 43 days for the brand vancomycin (Vancocin®) infusion (96% ± 2%) and up to 57 days for the generic (Vancomycine®) (95% ± 4%). The solutions prepared either from brand or generic vancomycin hydrochloride were chemically stable more than one month (43 days for the brand and 57 days for the generic solution) and could be prepared in advance in a centralized intravenous additive service facility.

  7. Long-term stability of organic carbon-stimulated chromatereduction in contaminated soils, and its relation to manganese redoxstatus

    Energy Technology Data Exchange (ETDEWEB)

    Tokunaga, Tetsu K.; Wan, Jiamin; Lanzirotti, Antonio; Sutton,Steve R.; Newville, Matthew; Rao, William

    2007-03-13

    In-situ reduction of toxic Cr(V1) to less hazardous Cr(II1)is becoming a popular strategy for remediating contaminated soils.However, the long term stability of reduced Cr remains to be understood,especially given the common presence of MnfIIIJV) oxides that reoxidizeCr(II1). This 4.6 year laboratory study tracked Cr and Mn redoxtransformations in soils contaminated with Cr(V1) which were then treatedwith different amounts of organic carbon (OC). Changes in Cr and Mnoxidation states within soils were directly and nondestructively measuredusing micro X-ray absorption near edge structure spectroscopy. Chromatereduction was roughly lst-order, and the extent of reduction was enhancedwith higher OC additions. However, significant Cr(||1) reoxidationoccurred in soils exposed to the highest Cr(V1) concentrations (2,560 mgkg"'). Transient Cr(II1) reoxidation up to 420 mg kg1 was measured at 1.1years after OC treatment, followed by further reduction. Chromateconcentrations increased by 220 mg kgm1a t the end of the study (4.6years) in one soil. The causal role that Mn oxidation state had inreoxidizing Cr was supported by trends in Mn K-edge energies. Theseresults provide strong evidence for longterm dependence of soil Croxidation states on balances between OC availability and Mn redoxstatus.

  8. Testing promotes long-term learning via stabilizing activation patterns in a large network of brain areas.

    Science.gov (United States)

    Keresztes, Attila; Kaiser, Daniel; Kovács, Gyula; Racsmány, Mihály

    2014-11-01

    The testing effect refers to the phenomenon that repeated retrieval of memories promotes better long-term retention than repeated study. To investigate the neural correlates of the testing effect, we used event-related functional magnetic resonance imaging methods while participants performed a cued recall task. Prior to the neuroimaging experiment, participants learned Swahili-German word pairs, then half of the word pairs were repeatedly studied, whereas the other half were repeatedly tested. For half of the participants, the neuroimaging experiment was performed immediately after the learning phase; a 1-week retention interval was inserted for the other half of the participants. We found that a large network of areas identified in a separate 2-back functional localizer scan were active during the final recall of the word pair associations. Importantly, the learning strategy (retest or restudy) of the word pairs determined the manner in which the retention interval affected the activations within this network. Recall of previously restudied memories was accompanied by reduced activation within this network at long retention intervals, but no reduction was observed for previously retested memories. We suggest that retrieval promotes learning via stabilizing cue-related activation patterns in a network of areas usually associated with cognitive and attentional control functions.

  9. Long-term spatiotemporal stability and dynamic changes in the haemoparasite community of bank voles (Myodes glareolus) in NE Poland.

    Science.gov (United States)

    Bajer, Anna; Welc-Falęciak, Renata; Bednarska, Małgorzata; Alsarraf, Mohammed; Behnke-Borowczyk, Jolanta; Siński, Edward; Behnke, Jerzy M

    2014-08-01

    Long-term field studies on parasite communities are rare but provide a powerful insight into the ecological and evolutionary processes shaping host-parasite interactions. The aim of our study was to identify the principal factors regulating long-term trends in the haemoparasite communities of bank voles, and to this end, we sampled three semi-isolated populations of bank voles (n = 880) in 1999, 2002, 2006 and 2010 in the Mazury lake district region of NE Poland. Overall, 90.8 % of the bank voles harboured at least one of the species of haemoparasites studied. Whilst overall prevalence (all species combined) did not vary significantly between the surveys, different temporal changes were detected among voles in each of the three sites. In voles from Urwitałt, prevalence increased consistently with successive surveys, whereas in Tałty, the peak years were 2002 and 2006, and in Pilchy, prevalence oscillated without a clear pattern. Across the study, bank voles harboured a mean of 1.75 ± 0.034 haemoparasite species, and species richness remained stable with no significant between-year fluctuations or trends. However, each of the five constituent species/genera showed a different pattern of spatio-temporal changes. The overall prevalence of Babesia microti was 4.9 %, but this varied significantly between years peaking in 2006 and declining again by 2010. For Bartonella spp., overall prevalence was 38.7 %, and this varied with year of study, but the temporal pattern of changes differed among the three sites. The overall prevalence of Haemobartonella (Mycoplasma) was 68.3 % with an increase in prevalence with year of study in all three sites. Hepatozoon erhardovae had an overall prevalence of 46.8 % but showed a marked reduction with each successive year of the study, and this was consistent in all three sites. The overall prevalence of Trypanosoma evotomys was 15.4 % varying significantly between sites, but showing temporal stability. While overall prevalence

  10. Integrated community profiling indicates long-term temporal stability of the predominant faecal microbiota in captive cheetahs.

    Science.gov (United States)

    Becker, Anne A M J; Janssens, Geert P J; Snauwaert, Cindy; Hesta, Myriam; Huys, Geert

    2015-01-01

    Understanding the symbiotic relationship between gut microbes and their animal host requires characterization of the core microbiota across populations and in time. Especially in captive populations of endangered wildlife species such as the cheetah (Acinonyx jubatus), this knowledge is a key element to enhance feeding strategies and reduce gastrointestinal disorders. In order to investigate the temporal stability of the intestinal microbiota in cheetahs under human care, we conducted a longitudinal study over a 3-year period with bimonthly faecal sampling of 5 cheetahs housed in two European zoos. For this purpose, an integrated 16S rRNA DGGE-clone library approach was used in combination with a series of real-time PCR assays. Our findings disclosed a stable faecal microbiota, beyond intestinal community variations that were detected between zoo sample sets or between animals. The core of this microbiota was dominated by members of Clostridium clusters I, XI and XIVa, with mean concentrations ranging from 7.5-9.2 log10 CFU/g faeces and with significant positive correlations between these clusters (Pcheetahs. The fifth animal in the study suffered from intermediate episodes of vomiting and diarrhea during the monitoring period and exhibited remarkably more change (39.4%). This observation may reflect the temporary impact of perturbations such as the animal's compromised health, antibiotic administration or a combination thereof, which temporarily altered the relative proportions of Clostridium clusters I and XIVa. In conclusion, this first long-term monitoring study of the faecal microbiota in feline strict carnivores not only reveals a remarkable compositional stability of this ecosystem, but also shows a qualitative and quantitative similarity in a defined set of faecal bacterial lineages across the five animals under study that may typify the core phylogenetic microbiome of cheetahs.

  11. Integrated community profiling indicates long-term temporal stability of the predominant faecal microbiota in captive cheetahs.

    Directory of Open Access Journals (Sweden)

    Anne A M J Becker

    Full Text Available Understanding the symbiotic relationship between gut microbes and their animal host requires characterization of the core microbiota across populations and in time. Especially in captive populations of endangered wildlife species such as the cheetah (Acinonyx jubatus, this knowledge is a key element to enhance feeding strategies and reduce gastrointestinal disorders. In order to investigate the temporal stability of the intestinal microbiota in cheetahs under human care, we conducted a longitudinal study over a 3-year period with bimonthly faecal sampling of 5 cheetahs housed in two European zoos. For this purpose, an integrated 16S rRNA DGGE-clone library approach was used in combination with a series of real-time PCR assays. Our findings disclosed a stable faecal microbiota, beyond intestinal community variations that were detected between zoo sample sets or between animals. The core of this microbiota was dominated by members of Clostridium clusters I, XI and XIVa, with mean concentrations ranging from 7.5-9.2 log10 CFU/g faeces and with significant positive correlations between these clusters (P<0.05, and by Lactobacillaceae. Moving window analysis of DGGE profiles revealed 23.3-25.6% change between consecutive samples for four of the cheetahs. The fifth animal in the study suffered from intermediate episodes of vomiting and diarrhea during the monitoring period and exhibited remarkably more change (39.4%. This observation may reflect the temporary impact of perturbations such as the animal's compromised health, antibiotic administration or a combination thereof, which temporarily altered the relative proportions of Clostridium clusters I and XIVa. In conclusion, this first long-term monitoring study of the faecal microbiota in feline strict carnivores not only reveals a remarkable compositional stability of this ecosystem, but also shows a qualitative and quantitative similarity in a defined set of faecal bacterial lineages across the five

  12. Enhancement of electron emission and long-term stability of tip-type carbon nanotube field emitters via lithium coating

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong-Pil [Health and Medical Equipment R and D Team, Samsung Electronics, Suwon, Gyeonggi-do 443-742 (Korea, Republic of); Chang, Han-Beet; Kim, Bu-Jong [Dept. of Electronic Systems Engineering, Hanyang University, Ansan, Gyeonggi-do 426-791 (Korea, Republic of); Park, Jin-Seok, E-mail: jinsp@hanyang.ac.kr [Dept. of Electronic Systems Engineering, Hanyang University, Ansan, Gyeonggi-do 426-791 (Korea, Republic of)

    2013-01-01

    Carbon nanotubes (CNTs) were deposited on conical tip-type substrates via electrophoresis and coated with lithium (Li) thin films with diverse thicknesses via electroplating. For the as-deposited (i.e., without Li coating) CNT, the turn-on (or triggering) electric field was 0.92 V/μm, and the emission current, which was generated at an applied field of 1.2 V/μm was 56 μA. In the case of the 4.7 nm-thick Li-coated CNT, the turn-on field decreased to 0.65 V/μm and the emission current at the same applied field increased more than ten times to 618 μA. The analysis based on the Kelvin probe measurement and Fowler–Nordheim theory indicated that the coating of Li caused a loss in the structural-aspect-ratio of the CNTs and it reduced their effective work functions from 5.36 eV to 4.90 eV, which led to a great improvement of their electron emission characteristics. The results obtained in this study also showed that the long-term emission stability could be enhanced by the coating of thin Li films on CNTs. - Highlights: ► CNTs are deposited via electrophoretic deposition (EPD). ► Thin films of Li are coated on CNTs via electroplating, without plasma damage. ► Li coating enhanced field emission properties and emission stability of CNTs. ► The effective work functions and field enhancement factors of CNTs are evaluated.

  13. Aspartame-stabilized gold-silver bimetallic biocompatible nanostructures with plasmonic photothermal properties, antibacterial activity, and long-term stability.

    Science.gov (United States)

    Fasciani, Chiara; Silvero, M Jazmin; Anghel, Maria Alexandra; Argüello, Gerardo A; Becerra, Maria Cecilia; Scaiano, Juan C

    2014-12-17

    Gold-silver core-shell nanoparticles stabilized with a common sweetener, aspartame (AuNP@Ag@Asm), combine the antimicrobial properties of silver with the photoinduced plasmon-mediated photothermal effects of gold. The particles were tested with several bacterial strains, while biocompatibility was verified with human dermal fibroblasts.

  14. Estimation of absorbed dose in clinical radiotherapy linear accelerator beams: Effect of ion chamber calibration and long-term stability.

    Science.gov (United States)

    Ravichandran, Ramamoorthy; Binukumar, Johnson Pichy; Davis, Cheriyathmanjiyil Antony

    2013-10-01

    The measured dose in water at reference point in phantom is a primary parameter for planning the treatment monitor units (MU); both in conventional and intensity modulated/image guided treatments. Traceability of dose accuracy therefore still depends mainly on the calibration factor of the ion chamber/dosimeter provided by the accredited Secondary Standard Dosimetry Laboratories (SSDLs), under International Atomic Energy Agency (IAEA) network of laboratories. The data related to Nd,water calibrations, thermoluminescent dosimetry (TLD) postal dose validation, inter-comparison of different dosimeter/electrometers, and validity of Nd,water calibrations obtained from different calibration laboratories were analyzed to find out the extent of accuracy achievable. Nd,w factors in Gray/Coulomb calibrated at IBA, GmBH, Germany showed a mean variation of about 0.2% increase per year in three Farmer chambers, in three subsequent calibrations. Another ion chamber calibrated in different accredited laboratory (PTW, Germany) showed consistent Nd,w for 9 years period. The Strontium-90 beta check source response indicated long-term stability of the ion chambers within 1% for three chambers. Results of IAEA postal TL "dose intercomparison" for three photon beams, 6 MV (two) and 15 MV (one), agreed well within our reported doses, with mean deviation of 0.03% (SD 0.87%) (n = 9). All the chamber/electrometer calibrated by a single SSDL realized absorbed doses in water within 0.13% standard deviations. However, about 1-2% differences in absorbed dose estimates observed when dosimeters calibrated from different calibration laboratories are compared in solid phantoms. Our data therefore imply that the dosimetry level maintained for clinical use of linear accelerator photon beams are within recommended levels of accuracy, and uncertainties are within reported values.

  15. Long-term-stability of relationship structure in family groups of common marmosets, and its link to proactive prosociality.

    Science.gov (United States)

    Finkenwirth, Christa; Burkart, Judith M

    2017-05-01

    Cooperatively breeding, group-living common marmosets show differentiated relationships, where more strongly bonded dyads within a group engage more in affiliative interactions than less strongly bonded ones. Intriguingly, recent results suggest that strong bonds do not only occur between breeding partners but between individuals from any sex or status, and that strong-bond partners exhibit correlated oxytocin fluctuations (dyadic oxytocin synchrony, OTS) over a period of six weeks. To date, it is unclear whether such relationships are stable over time and whether they are also reflected in higher partner-specific proactive prosociality. To assess the long-term stability of the relationship structure of common marmoset family groups, we investigated whether hormonal and behavioral markers of group structure (dyadic OTS, dyadic affiliation, and individual group integration) in common marmoset families remained stable over a period of six months. We collected baseline urinary OT and social behavior of 36 dyads from three family groups in a non-reproductive period (period A), and again six months later, around the birth of new infants (period B). Patterns of dyadic OTS, dyadic affiliation, and individual group integration were consistent between the two study periods. Oxytocin data from a fourth group (10 dyads), collected in two non-reproductive periods separated by a period of more than five years, could replicate this finding. Furthermore, OTS was also correlated with proactive prosociality that was assessed experimentally for 38 dyads during an earlier study. These results suggest that differentiated relationships are stable over time, even between group members other than the breeding pair, and that more strongly bonded partners also show higher levels of proactive prosociality. Future studies are necessary to identify whether these relationships have an adaptive function, perhaps with regard to positive consequences on cooperativeness.

  16. Long-term stability of neural prosthetic control signals from silicon cortical arrays in rhesus macaque motor cortex

    Science.gov (United States)

    Chestek, Cynthia A.; Gilja, Vikash; Nuyujukian, Paul; Foster, Justin D.; Fan, Joline M.; Kaufman, Matthew T.; Churchland, Mark M.; Rivera-Alvidrez, Zuley; Cunningham, John P.; Ryu, Stephen I.; Shenoy, Krishna V.

    2011-08-01

    Cortically-controlled prosthetic systems aim to help disabled patients by translating neural signals from the brain into control signals for guiding prosthetic devices. Recent reports have demonstrated reasonably high levels of performance and control of computer cursors and prosthetic limbs, but to achieve true clinical viability, the long-term operation of these systems must be better understood. In particular, the quality and stability of the electrically-recorded neural signals require further characterization. Here, we quantify action potential changes and offline neural decoder performance over 382 days of recording from four intracortical arrays in three animals. Action potential amplitude decreased by 2.4% per month on average over the course of 9.4, 10.4, and 31.7 months in three animals. During most time periods, decoder performance was not well correlated with action potential amplitude (p > 0.05 for three of four arrays). In two arrays from one animal, action potential amplitude declined by an average of 37% over the first 2 months after implant. However, when using simple threshold-crossing events rather than well-isolated action potentials, no corresponding performance loss was observed during this time using an offline decoder. One of these arrays was effectively used for online prosthetic experiments over the following year. Substantial short-term variations in waveforms were quantified using a wireless system for contiguous recording in one animal, and compared within and between days for all three animals. Overall, this study suggests that action potential amplitude declines more slowly than previously supposed, and performance can be maintained over the course of multiple years when decoding from threshold-crossing events rather than isolated action potentials. This suggests that neural prosthetic systems may provide high performance over multiple years in human clinical trials.

  17. Long-term Stability and Oceanic Mean State Simulated by the Coupled Model FGOALS-s2

    Institute of Scientific and Technical Information of China (English)

    LIN Pengfei; YU Yongqiang; LIU Hailong

    2013-01-01

    We describe the long-term stability and mean climatology of oceanic circulations simulated by version 2 of the Flexible Global Ocean-Atmosphere-Land System model (FGOALS-s2).Driven by pre-industrial forcing,the integration of FGOALS-s2 was found to have remained stable,with no obvious climate drift over 600 model years.The linear trends of sea SST and sea surface salinity (SSS) were-0.04℃ (100 yr)-1 and 0.01 psu (100 yr)-1,respectively.The simulations of oceanic temperatures,wind-driven circulation and thermohaline circulation in FGOALS-s2 were found to be comparable with observations,and have been substantially improved over previous FGOALS-s versions (1.0 and 1.1).However,significant SST biases (exceeding 3℃) were found around strong western boundary currents,in the East China Sea,the Sea of Japan and the Barents Sea.Along the eastern coasts in the Pacific and Atlantic Ocean,a warm bias (>3℃) was mainly due to overestimation of net surface shortwave radiation and weak oceanic upwelling.The difference of SST biases in the North Atlantic and Pacific was partly due to the errors of meridional heat transport.For SSS,biases exceeding 1.5 psu were located in the Arctic Ocean and around the Gulf Stream.In the tropics,freshwater biases dominated and were mainly caused by the excess of precipitation.Regarding the vertical dimension,the maximal biases of temperature and salinity were located north of 65°N at depths of greater than 600 m,and their values exceeded 4℃ and 2 psu,respectively.

  18. Understanding the long term ecosystem stability of a fen mire by analyzing subsurface geology, eco-hydrology and nutrient stoichiometry - Case study of the Rospuda valley (NE Poland)

    NARCIS (Netherlands)

    Jabłońska, Ewa; Falkowski, Tomasz; Chormański, Jarosław; Jarzombkowski, Filip; Kłosowski, Stanisław; Okruszko, Tomasz; Pawlikowski, Paweł; Theuerkauf, Martin; Wassen, Martin J.; Kotowski, Wiktor

    2014-01-01

    We explored the background of differences in long-term stability between two parts in an undisturbed mire system (Rospuda fen, NE Poland). We re-constructed the Holocene history of the mire and compared it with current vegetation, water level dynamics, water chemistry and nutrient availability in tw

  19. An investigation on the chemical stability and a novel strategy for long-term stabilization of diphenylalanine nanostructures in aqueous solution

    Directory of Open Access Journals (Sweden)

    H. Nezammahalleh

    2015-01-01

    Full Text Available The stability of diphenylalanine (FF microwires and microtubes in phosphate buffer solution was investigated and a novel strategy was developed for their chemical stabilization. This stability investigation was carried out by optical microscopy and by high performance liquid chromatography (HPLC. These microstructures dissolve in the solution depending upon their degree of FF saturation. The dissolution mechanisms of the structures in kinetically limited processes were found by accurately fitting the experimental dissolution data to a theoretical kinetic equation. The dissolution data were well fitted to the particular Avrami-Erofe’ev kinetic expression (R2 > 0.98. These findings suggest that the structures can be stabilized by a decrease in the hydration of the constituent molecules thorough a chemical conformational induced transition upon heat treatment. The stable microtubes were fabricated in a novel three step procedure consisting of the reduction of silver ions in unstable FF microtubes by a citrate reductant, the stabilization by chemical conformational induced transition upon heat treatment, and the consequent oxidation of the reduced silver by a persulfate oxidant. These materials were characterized by electron microscopy and powder X-ray diffraction techniques. The long-term stability of both structures was also confirmed by optical microscopy and HPLC.

  20. Studies on Stability of a Novel Cathode Material for MCFC

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The stability of NiO and oxidized nickel-niobium surface alloy electrode under various molten carbonate fuel cell(MCFC) cathode conditions were investigated by determination of equilibrium solubility of nickel ions in the carbonate melt of the two electrode materials.It is found that under MCFC cathode conditions the stability of NiO electrode is improved significantly by the deposition of niobium.As far as stability is concerned,oxidized nickel-niobium alloy electrode can be considered as a candidate for cathode material of MCFC.

  1. LONG-TERM STABILITY OF THE LOCAL GROUND CONTROL NETWORK AT THE CO-LOCATION SITE OF MEDICINA

    Science.gov (United States)

    Abbondanza, C.; Sarti, P.; Legrand, J.

    2009-12-01

    ITRF combinations rely on the availability of accurate tie vectors linking reference points of space geodetic techniques. Co-located instruments are assumed to move consistently and no local relative motion is taken into account. Instabilities may degrade the quality of the co-location itself and perturb the result of ITRF combinations. This work aims to determine the stability of the local ground control network at Medicina (Italy) with independent surveying methods. The observatory hosts a co-location between a VLBI telescope and two GPS antennas, MEDI and MSEL. It is located in the Po Plain where thick layers of clays are the prevalent soil characteristics. Hence, provision of long term stability of geodetic monuments is a challenge and monitoring their stability is an issue. MEDI and the VLBI station regularly contribute to the determination of ITRF, while MSEL is part of the EUREF network. A set of five tie vectors observations linking the VLBI and MEDI reference points was acquired between 2001 and 2007. It is our main tool for performing local deformation analysis. Additionally, the GPS time series of MEDI and MSEL were used to cross check and confirm the local instability detected by terrestrial methods. To achieve a rigorous and reliable investigation of the local stability, multi-epoch terrestrial observations were homogeneously processed according to common parameterizations in a consistent reference frame. Similarly, continuous GPS observations from MEDI and MSEL were analysed according to the new EPN reprocessing strategy in order to monitor the short baseline between MEDI and MSEL; to spotlight any change in its length. Both approaches confirm differential motions at the site which can be related to monument instabilities originated by the particularly unfavourable local geological setting and the inapt design of the monuments foundation. The monuments move non homogeneously at rates reaching up to 1.6 mm/year, this value being comparable to intra

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

    Science.gov (United States)

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

    2016-11-01

    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.

  3. Using the Sonoran Desert test site to monitor the long-term radiometric stability of the Landsat TM/ETM+ and Terra MODIS sensors

    Science.gov (United States)

    Angal, A.; Xiong, X.; Choi, T.; Chander, G.; Wu, A.

    2009-01-01

    Pseudo-invariant ground targets have been extensively used to monitor the long-term radiometric calibration stability of remote sensing instruments. The NASA MODIS Characterization Support Team (MCST), in collaboration with members from the U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center, has previously demonstrated the use of pseudo-invariant ground sites for the long-term stability monitoring of Terra MODIS and Landsat 7 ETM+ sensors. This paper focuses on the results derived from observations made over the Sonoran Desert. Additionally, Landsat 5 TM data over the Sonoran Desert site were used to evaluate the temporal stability of this site. Top-ofatmosphere (TOA) reflectances were computed for the closely matched TM, ETM+, and MODIS spectral bands over selected regions of interest. The impacts due to different viewing geometries, or the effect of test site Bi-directional Reflectance Distribution Function (BRDF), are also presented. ?? 2009 SPIE.

  4. Long-term evolution of techno-social networks: Statistical regularities, predictability and stability of social behaviors

    CERN Document Server

    Godoy-Lorite, Antonia; Sales-Pardo, Marta

    2016-01-01

    In social networks, individuals constantly drop ties and replace them by new ones in a highly unpredictable fashion. This highly dynamical nature of social ties has important implications for processes such as the spread of information or of epidemics. Several studies have demonstrated the influence of a number of factors on the intricate microscopic process of tie replacement, but the macroscopic long-term effects of such changes remain largely unexplored. Here we investigate whether, despite the inherent randomness at the microscopic level, there are macroscopic statistical regularities in the long-term evolution of social networks. In particular, we analyze the email network of a large organization with over 1,000 individuals throughout four consecutive years. We find that, although the evolution of individual ties is highly unpredictable, the macro-evolution of social communication networks follows well-defined statistical laws, characterized by exponentially decaying log-variations of the weight of socia...

  5. Development of a baseline-temperature correction methodology for electrochemical sensors and its implications for long-term stability

    Science.gov (United States)

    Popoola, Olalekan A. M.; Stewart, Gregor B.; Mead, Mohammed I.; Jones, Roderic L.

    2016-12-01

    Recent studies have shown that (three-electrode) electrochemical sensors can be utilised for air quality monitoring and exposure assessment. The long-term performance of these sensors is however, often limited by the effects of ambient meteorological parameters on the sensor baseline, in particular temperature. If electrochemical (EC) sensors are to be adopted for air quality measurement over extended periods (months), this effect must be accounted for. Recent long-term, ambient measurements of CO, NO and NO2 using EC sensors have revealed that temperature (and relative humidity (RH)) had an effect on the baseline which was more pronounced in the case of NO sensors with coefficient of determination, R2 of 0.9 when compared to CO and NO2 with R2 air quality gases at the parts per billion volume (ppb) mixing ratio level typical of ambient conditions in the urban environment.

  6. Investigation on Long-term Creep Rupture Properties and Microstructure Stability of Fe-Ni based Alloy Ni-23Cr-7W at 700°C

    DEFF Research Database (Denmark)

    Tokairin, Tsuyoshi; Dahl, Kristian Vinter; Danielsen, Hilmar Kjartansson

    2013-01-01

    Long-term creep rupture properties and microstructural stability of Fe–Ni based alloy Ni–23Cr–7W (HR6W, ASME Code Case 2684) were experimentally investigated. Crept specimens at 700 °C for durations up to 37,667 h were chosen, the microstructure evolution during creep was characterized. Besides...... for the main strengthening precipitate, Laves phase. The alloy was proven to have good microstructural stability without observable coarsening of strengthening precipitates during long-term creep up to around 37,667 h. It was also verified that the growth kinetics of Laves phase can be well described...... the MC and M23C6 carbides found in the as-received sample, the formation of α-W phase, α-Cr phase and Laves phase in crept samples were confirmed with scanning/transmission electron microscopes. Statistical quantitative image analysis was used to evaluate the precipitation behavior and growth kinetics...

  7. Long-term stability of FeSO4 and H2SO4 treated chromite ore processing residue (COPR): Importance of H(+) and SO4(2).

    Science.gov (United States)

    Wang, Xin; Zhang, Jingdong; Wang, Linling; Chen, Jing; Hou, Huijie; Yang, Jiakuan; Lu, Xiaohua

    2017-01-05

    In this study, the long-term stability of Cr(VI) in the FeSO4 and H2SO4 (FeSO4-H2SO4) treated chromite ore processing residue (COPR) after 400 curing days and the stabilization mechanisms were investigated. FeSO4-H2SO4 treatment significantly reduced toxicity characteristic leaching procedure (TCLP) and synthetic precipitation leaching procedure (SPLP) Cr(VI) concentrations to lower than the regulatory limit of 1.5mgL(-1) (HJ/T 301-2007, China EPA) even for the samples curing 400days, achieving an outstanding long-term stability. Our independent leaching tests revealed that H(+) and SO4(2-) have synergistic effect on promoting the release of Cr(VI), which would make Cr(VI) easier accessed by Fe(II) during stabilization. The contributions of H(+) and SO4(2-) to Cr(VI) release ratio were 25%-44% and 19%-38%, respectively, as 5mol H2SO4 per kg COPR was used. X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and alkaline digestion analyses were also employed to interpret the possible stabilization mechanism. Cr(VI) released from COPR solid was reduced to Cr(III) by Fe(II), and then formed stable FexCr(1-x)(OH)3 precipitate. This study provides a facile and reliable scheme for COPR stabilization, and verifies the excellent long-term stability of the FeSO4-H2SO4 treated COPR.

  8. Influence of Z-phase on long-term creep stability of martensitic 9-12% Cr steels

    Energy Technology Data Exchange (ETDEWEB)

    Danielsen, Hilmar K. [Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Mechanical Engineering; Hald, John [DONG Energy A/S (Denmark); Vattenfall (Denmark)

    2010-07-01

    The long-term creep strength of the new generation of martensitic creep resistant 9-12%Cr steels since the well-known steel Grade 91 relies strongly on particle strengthening by fine Mn nitrides based on V and Nb. During long-term high-temperature exposures the Mn nitrides may be replaced by the thermodynamically more stable Z-phases (Cr(V,Nb)N) causing a breakdown in creep strength. Cr contents above 10.5% strongly accelerate Z-phase precipitation, which explains the lack of success for all attempts to develop martensitic creep resistant steels with high Cr content for oxidation protection. However 9%Cr steels do not seem to be affected by the Z-phase. Careful control of the Z-phase precipitation process has led to the design of experimental 12%Cr martensitic steels strengthened by fine Z-phase nitrides based on Nb or Ta. Such steels may again enable the combination of high strength and oxidation resistance in the same alloy. This opens a new pathway for further alloy development of the heat resistant martensitic steels. (orig.)

  9. Long-Term Stability and Safety of Transgenic Cultured Epidermal Stem Cells in Gene Therapy of Junctional Epidermolysis Bullosa

    Directory of Open Access Journals (Sweden)

    Laura De Rosa

    2014-01-01

    Full Text Available We report a long-term follow-up (6.5 years of a phase I/II clinical trial envisaging the use of autologous genetically modified cultured epidermal stem cells for gene therapy of junctional epidermolysis bullosa, a devastating genetic skin disease. The critical goals of the trial were to evaluate the safety and long-term persistence of genetically modified epidermis. A normal epidermal-dermal junction was restored and the regenerated transgenic epidermis was found to be fully functional and virtually indistinguishable from a normal control. The epidermis was sustained by a discrete number of long-lasting, self-renewing transgenic epidermal stem cells that maintained the memory of the donor site, whereas the vast majority of transduced transit-amplifying progenitors were lost within the first few months after grafting. These data pave the way for the safe use of epidermal stem cells in combined cell and gene therapy for genetic skin diseases.

  10. Extent of copper tolerance and consequences for functional stability of the ammonia-oxidizing community in long-term copper-contaminated soils.

    Science.gov (United States)

    Mertens, Jelle; Wakelin, Steven A; Broos, Kris; McLaughlin, Mike J; Smolders, Erik

    2010-01-01

    Adaptation of soil microbial communities to elevated copper (Cu) concentrations has been well documented. However, effects of long-term Cu exposure on adaptation responses associated with functional stability and structural composition within the nitrifying community are still unknown. Soils were sampled in three field sites (Denmark, Thailand, and Australia) where Cu gradients had been established from 3 to 80 years prior to sampling. In each field site, the potential nitrification rate (PNR) decreased by over 50% with increasing soil Cu, irrespective of a 20 to >200-fold increase in Cu tolerance (at the highest soil Cu) among the nitrifying communities. This increased tolerance was associated with decreasing numbers (15-120-fold) of ammonia-oxidizing bacteria (AOB), except in the oldest contaminated field site, decreasing numbers of ammonia-oxidizing archaea (AOA; 10-130-fold) and differences in the operational taxonomic unit (OTU) composition of the AOB and, to a lesser extent, AOA communities. The sensitivity of nitrifying communities, previously under long-term Cu exposure, to additional stresses was assessed. Nitrification in soils from the three field sites was measured following acidification, pesticide addition, freeze-thaw cycles, and dry-rewetting cycles. Functional stability of the nitrification process was assessed immediately after stress application (resistance) and after an additional three weeks of incubation (resilience). No indications were found that long-term Cu exposure affected the sensitivity to the selected stressors, suggesting that resistance and resilience were unaffected. It was concluded that the nitrifying community changed structurally in all long-term Cu-exposed field sites and that these changes were associated with increased Cu tolerance but not with a loss of functional stability.

  11. Long-term stabilization by radiosurgery of a secondary focal anaplastic transformation in a surgically treated WHO grade II oligodendroglioma. A case report.

    Science.gov (United States)

    Yordanova, Y N; Rodriguez-Arribas, M-A; Duffau, H

    2015-02-01

    We report on a young woman with a left temporal diffuse low-grade glioma treated initially by a subtotal resection. A focal anaplastic area appeared 5years later and was treated by radiosurgery. A long-time stabilization was therefore obtained and lasted even after pregnancy, which is a known factor of faster tumour progression. This report shows that radiosurgery could be an option in the multimodal treatment of a selected group of patients with focal malignant transformation of diffuse low-grade glioma. It could permit long-term stabilization of the tumour without any other adjuvant treatment and without compromising the quality of life.

  12. A method to improve the stability and accuracy of ANN- and SVM-based time series models for long-term groundwater level predictions

    Science.gov (United States)

    Yoon, Heesung; Hyun, Yunjung; Ha, Kyoochul; Lee, Kang-Kun; Kim, Gyoo-Bum

    2016-05-01

    The prediction of long-term groundwater level fluctuations is necessary to effectively manage groundwater resources and to assess the effects of changes in rainfall patterns on groundwater resources. In the present study, a weighted error function approach was utilised to improve the performance of artificial neural network (ANN)- and support vector machine (SVM)-based recursive prediction models for the long-term prediction of groundwater levels in response to rainfall. The developed time series models were applied to groundwater level data from 5 groundwater-monitoring stations in South Korea. The results demonstrated that the weighted error function approach can improve the stability and accuracy of recursive prediction models, especially for ANN models. The comparison of the model performance showed that the recursive prediction performance of the SVM was superior to the performance of the ANN in this case study.

  13. Long-term effective population sizes, temporal stability of genetic composition and potential for local adaptation in anadromous brown trout ( Salmo trutta ) populations

    DEFF Research Database (Denmark)

    Hansen, Michael Møller; Ruzzante, D.E.; Eg Nielsen, Einar;

    2002-01-01

    (3 km) river showed Ne greater than or equal to 300. Assuming a stepping-stone model of gene flow we considered the relative roles of gene flow, random genetic drift and selection to assess the possibilities for local adaptation. The requirements for local adaptation were fulfilled, but only......We examined the long-term temporal (1910s to 1990s) genetic variation at eight microsatellite DNA loci in brown trout (Salmo trutta L) collected from five anadromous populations in Denmark to assess the long-term stability of genetic composition and to estimate effective population sizes (N......-e). Contemporary and historical samples consisted of tissue and archived scales, respectively. Pairwise Theta(ST) estimates, a hierarchical analysis of molecular variance (AMOVA) and multidimensional scaling analysis of pairwise genetic distances between samples revealed much closer genetic relationships among...

  14. [Stabilizing the social and health status of drug dependent patients with methadone. Long-term maintainance therapy--Vienna results].

    Science.gov (United States)

    Loimer, N; Werner, E; Hollerer, E; Pfersmann, V; Schmid-Siegel, B; Presslich, O

    1991-01-01

    On September 25th, 1987 methadone was legalized in Austria for therapeutic use in drug addiction treatment in case of: 1. Long-term drug addiction with intravenous application of the drug, and several unsuccessful withdrawal therapies and/or 2. opiate addiction through intravenous application of the drug along with an existing HIV-1 infection. Since than, 291 patients were treated with methadone at the drug-dependency outpatient clinic of the Psychiatric Clinic of the University of Vienna. In 1990, 96 patients treated for more than one year were investigated using a standardized questionnaire. The image in which crime, prostitution, poverty, ill health all merge was broken by this decriminalization. Methadone treatment offers a first step toward social rehabilitation for drug addicts who have been living as criminals on the fringe of society.

  15. Long-term stability of grazing lawns in a small protected area, the Mountain Zebra National Park

    Directory of Open Access Journals (Sweden)

    Peter Novellie

    2013-02-01

    Full Text Available We examined a heavily grazed plant community dominated by creeping grass species with the aim of, (1 determining its response to the exclusion of grazing and (2 its long-term persistence. This plant community was particularly favoured by wild ungulate species that prefer short grasses – blesbok (Damaliscus dorcas phillipsi, springbok (Antidorcas marsupialis and black wildebeest (Connochaetes gnou. Exclusion of grazing by large herbivores by means of fencing resulted in the virtual disappearance of the creeping grasses and their replacement by tall tufted species. On plots that remained unfenced, the plant species composition was found to be little changed after an interval of more than 20 years. The number large stock unit equivalents (LSU per ha carried by the plant community was used as a proxy for grazing intensity. Monitored for approximately 2 years at the start of the study, LSU per ha was found to greatly exceed levels recommended for commercial livestock production. This plant community conforms to a recently published definition of a grazing lawn, in that intense grazing promotes palatable, grazing-tolerant grass species.Conservation implications: The positive association between grazers and grazing-tolerant grass species evidently persisted for more than 20 years and there was no evidence of an increase in abundance of unpalatable plant species. Despite the small size of the park, which limited the extent of large herbivore movements, localised heavy grazing did not lead to range degradation.

  16. Long-term high-temperature and pH stability assessment of modern commercially available stationary phases by using retention factor analysis.

    Science.gov (United States)

    Haun, Jakob; Oeste, Katja; Teutenberg, Thorsten; Schmidt, Torsten C

    2012-11-09

    High-temperature liquid chromatography provides several advantages concerning HPLC method development and is needed to realize special hyphenation techniques. However, hardware limitations and stationary phase degradation can prevent the successful application of this technique. Therefore, column stability is of major importance. The presented study contains results of long-term high-temperature stability tests for eight modern commercially available HPLC stationary phases. Six of them were silica-based reversed-phase C18 columns tested according to an earlier reported procedure (Teutenberg, 2009 [12]). On the basis of the extended data set that covers a wide range of column technologies, a comparative approach using retention factor analysis was evaluated in order to categorize the columns according to their long-term high-temperature stability at 150 °C and changing pH value. This approach offers a more objective alternative to conventional listings in which temperature maxima are compared for columns tested under different conditions. Additionally, customized tests are presented for one promising polymer-based C18 stationary phase and an amide column for hydrophilic interaction liquid chromatography.

  17. Interphase FISH Demonstrates that Human Adipose Stromal Cells Maintain a High Level of Genomic Stability in Long-Term Culture

    OpenAIRE

    2008-01-01

    Human adipose stromal cells (ASCs) reside within the stromal-vascular fraction (SVF) in fat tissue, can be readily isolated, and include stem-like cells that may be useful for therapy. An important consideration for clinical application and functional studies of stem/progenitor cells is their capacity to maintain chromosome stability in culture. In this study, cultured ASC populations and ASC clones were evaluated at intervals for maintenance of chromosome stability. Uncultured SVF (uSVF) cel...

  18. A dense transparent polymeric single ion conductor for lithium ion batteries with remarkable long-term stability

    Science.gov (United States)

    Pan, Qiyun; Chen, Yazhou; Zhang, Yunfeng; Zeng, Danli; Sun, Yubao; Cheng, Hansong

    2016-12-01

    We report an outstanding electrochemical performance of a gel type lithium ion battery with long cycle life enabled by a dense transparent polymeric single ion conductor. The polymer electrolyte was synthesized by a side chain grafting method with 4-amino-4'-trifluoromethyl bis(benzene sulfonyl)imide grafted on side chains of poly(ethylene-alt-maleic anhydride) with a grafting ratio of 50%. Blending lithiated iononmers with poly(vinylidene fluoride-co-hexafluoropropylene) via a solution cast method results in a dense transparent film. The fabricated blend polymer electrolyte film has an ionic conductivity of 0.104 mS cm-1 at room temperature, a tensile strength of 15.5 MPa and percent elongation at break of 5%. A gel type single ion conductive polymeric lithium ion battery was assembled using the blend film as the separator as well as the electrolyte, LiFePO4/C mixed with ionomers as the cathode and a lithium foil as the anode. The battery delivers a reversible discharge capacity of 100 mAh g-1 at 1 C under room temperature for 1000 cycles without obvious decay. The stable cyclic imide and comb-like structure of the polymer is largely responsible for the excellent battery performance. The side chain grafted single ion conducting polymer electrolyte is well suited for large-scale production.

  19. Dynamic Relationship Between Biologically Active Soil Organic Carbon and Aggregate Stability in Long-Term Organically Fertilized Soils

    Institute of Scientific and Technical Information of China (English)

    LI Cheng-Liang; XU Jiang-Bing; HE Yuan-Qiu; LIU Yan-Li; FAN Jian-Bo

    2012-01-01

    Biologically active soil organic carbon (BASOC) is an important fraction of soil organic carbon (SOC),but our understanding of the correlation between BASOC and soil aggregate stability is limited.At an ecological experimental station (28° 04′-28° 37′ N,116°41′-117° 09′ E) in Yujiang County,Jiangxi Province,China,we analyzed the dynamic relationship between soil aggregate stability and BASOC content over time in the red soil (Udic Ferrosols) fertilized with a nitrogen-phosphorus-potassium chemical fertilizer (NPK)without manure or with NPK plus livestock manure or green manure.The dynamics of BASOC was evaluated using CO2 efflux,and soil aggregates were separated according to size using a wet-sieving technique.The soils fertilized with NPK plus livestock manure had a significantly higher content of BASOC and an improved aggregate stability compared to the soils fertilized with NPK plus green manure or NPK alone The BASOC contents in all fertilized soils decreased over time The contents of large aggregates (800-2000μm) dramatically decreased over the first 7 d of incubation,but the contents of small aggregates (< 800.μm) either remained the same or increased,depending on the incubation time and specific aggregate sizes.The aggregate stability did not differ significantly at the beginning and end of incubation,but the lowest stability inall fertilized soils occurred in the middle of the incubation,which implied that the soils had a strong resilience for aggregate stability.The change in BASOC content was only correlated with aggregate stability during the first 27 d of incubation.

  20. A new high-energy cathode for a Na-ion battery with ultrahigh stability.

    Science.gov (United States)

    Park, Young-Uk; Seo, Dong-Hwa; Kwon, Hyung-Soon; Kim, Byoungkook; Kim, Jongsoon; Kim, Haegyeom; Kim, Inkyung; Yoo, Han-Ill; Kang, Kisuk

    2013-09-18

    Large-scale electric energy storage is a key enabler for the use of renewable energy. Recently, the room-temperature Na-ion battery has been rehighlighted as an alternative low-cost technology for this application. However, significant challenges such as energy density and long-term stability must be addressed. Herein, we introduce a novel cathode material, Na1.5VPO4.8F0.7, for Na-ion batteries. This new material provides an energy density of ~600 Wh kg(-1), the highest value among cathodes, originating from both the multielectron redox reaction (1.2 e(-) per formula unit) and the high potential (~3.8 V vs Na(+)/Na) of the tailored vanadium redox couple (V(3.8+)/V(5+)). Furthermore, an outstanding cycle life (~95% capacity retention for 100 cycles and ~84% for extended 500 cycles) could be achieved, which we attribute to the small volume change (2.9%) upon cycling, the smallest volume change among known Na intercalation cathodes. The open crystal framework with two-dimensional Na diffusional pathways leads to low activation barriers for Na diffusion, enabling excellent rate capability. We believe that this new material can bring the low-cost room-temperature Na-ion battery a step closer to a sustainable large-scale energy storage system.

  1. Anthropogenic Charcoal Deposits: Analogues for the Long-Term Functioning and Stability of Biochar in European Soils?

    Science.gov (United States)

    Mugford, Ian; Street-Perrot, Alayne; Santín, Cristina; Denman, Huw

    2014-05-01

    Anthropogenic charcoal deposits, characterised by thick charcoal-rich soil horizons, offer an invaluable Late Quaternary record of pyrogenic carbon (PyC) additions to soils. A traditional source of archaeological, anthracological and palaeoecological data, the potential contribution of anthropogenic charcoal deposits to soil science and assessment of carbon (C) sequestration is often overlooked. If addition of biochar to soils is to form a key component of a low-C economy, crucial questions must be addressed relating to its longevity and behaviour in the soil environment. With rare exceptions, previous studies have focussed on short-term incubation experiments and field or pot trials, often neglecting important natural soil and environmental processes. This study addresses these issues by comparing the physicochemical properties of European anthropogenic charcoal-rich deposits, with 14C ages ranging from > 43 ka to Modern, to native soils (nearby control sites). We will present results from a study of 23 charcoal-rich soil cores, collected from a 'Pre-historic' ditch mound, a Bronze Age burnt mound, a Roman furnace, and post-mediaeval and Modern Meilers, situated along a climatic gradient from Mediterranean (Southern Italy) to Humid Temperate (South Wales). The ability of charcoal to alter fertility and retain plant-available nutrients was assessed by measuring soil cation- exchange capacity. Retention of refractory C by the charcoal deposits was evaluated from their total organic C (TOC) contents, atomic H:C and O:C ratios, and residues after acid- dichromate oxidation. Picked charcoal fragments were also compared with modern biochars and biomass using: 1) their thermogravimetric recalcitrance (R50) indices (Harvey et al. 2012); and 2) attenuated total reflectance (ATR) FT-IR data, to gauge the development of functional groups linked to the long-term oxidation of the particle surfaces. Radiocarbon dating was used to assess the ages of the deposits. Our study

  2. Long-term stabilization of a heterodyne metrology interferometer down to a noise level of 20 pm over an hour.

    Science.gov (United States)

    Niwa, Yoshito; Arai, Koji; Ueda, Akitoshi; Sakagami, Masaaki; Gouda, Naoteru; Kobayashi, Yukiyasu; Yamada, Yoshiyuki; Yano, Taihei

    2009-11-10

    A heterodyne metrology interferometer was stabilized down to a noise level of 20 picometers (pm) as a root-mean-square (RMS) value integrated between 0.3 mHz and 1 Hz. This noise level was achieved by employing active and passive interferometer stabilization techniques. The heterodyne interferometer was built on a 50 mm square ultralow expansion glass plate in order to reduce an optical path length change caused by temperature variation. An optical configuration of the interferometer is a Mach-Zehnder interferometer with a design as symmetric as possible so that a detection signal can be insensitive to homogeneous thermal expansion of the glass plate. The heterodyne frequency is actively controlled in order to suppress residual noises caused by optical path length changes outside of the glass plate as well as phase fluctuations of the heterodyne frequency source. Our stabilization scheme is considered useful in achieving the 20 pm noise level without a stable heterodyne frequency source, as well as temperature stabilization around a whole apparatus. This interferometer can be used in precise metrology applications, such as characterization of deformation for satellite optical components against thermal exposure.

  3. Long-term stability of frontal electroencephalographic asymmetry in adults with a history of depression and controls.

    Science.gov (United States)

    Vuga, Marike; Fox, Nathan A; Cohn, Jeffrey F; George, Charles J; Levenstein, Rachel M; Kovacs, Maria

    2006-02-01

    We investigated the stability in resting EEG across a 1- to 3-year interval in 49 adults (33 female and 16 male) with a history of unipolar depression (first onset prior to the age of 14) and 50 controls (33 female and 17 male) with no history of major psychopathology. Current depressive symptoms were quantified by self-report at both assessments. For the entire sample, EEG asymmetry in the alpha range was moderately stable (intraclass correlations between 0.39 and 0.61). Sex, history of depression, depressive symptom severity at Time 2, and change in symptom severity between Time 1 and Time 2 were unrelated to stability of EEG asymmetry. These findings support the view that resting frontal EEG asymmetry reflects a moderately stable individual difference in adults, irrespective of sex and history of depression.

  4. Achieving long-term stability of lipid nanoparticles: examining the effect of pH, temperature, and lyophilization

    Science.gov (United States)

    Ball, Rebecca L; Bajaj, Palak; Whitehead, Kathryn A

    2017-01-01

    The broadest clinical application of siRNA therapeutics will be facilitated by drug-loaded delivery systems that maintain stability and potency for long times under ambient conditions. In the present study, we seek to better understand the stability and effect of storage conditions on lipidoid nanoparticles (LNPs), which have been previously shown by our group and others to potently deliver RNA to various cell and organ targets both in vitro and in vivo. Specifically, this study evaluates the influence of pH, temperature, and lyophilization on LNP efficacy in HeLa cells. When stored under aqueous conditions, we found that refrigeration (2°C) kept LNPs the most stable over 150 days compared to storage in the −20°C freezer or at room temperature. Because the pH of the storage buffer was not found to influence stability, it is suggested that the LNPs be stored under physiologically appropriate conditions (pH 7) for ease of use. Although aggregation and loss of efficacy were observed when LNPs were subjected to freeze–thaw cycles, their stability was retained with the use of the cryoprotectants, trehalose, and sucrose. Initially, lyophilization of the LNPs followed by reconstitution in aqueous buffer also led to reductions in efficacy, most likely due to aggregation upon reconstitution. Although the addition of ethanol to the reconstitution buffer restored efficacy, this approach is not ideal, as LNP solutions would require dialysis prior to use. Fortunately, we found that the addition of trehalose or sucrose to LNP solutions prior to lyophilization facilitated room temperature storage and reconstitution in aqueous buffer without diminishing delivery potency. PMID:28115848

  5. Determination of genetic stability in long-term somatic embryogenic cultures and derived plantlets of cork oak using microsatellite markers.

    Science.gov (United States)

    Lopes, Tina; Pinto, Glória; Loureiro, João; Costa, Armando; Santos, Conceição

    2006-09-01

    Microsatellites were used to test genetic stability in somatic embryos (SE) of Quercus suber L. The SE were obtained by a simple somatic embryogenesis protocol: leaf explants from two adult plants (QsG0, QsG5) and from two juvenile plants (QsGM1, QsGM2) were inoculated on Murashige and Skoog (MS) medium with 2,4-dichlorophenoxyacetic acid and zeatin. Calluses with primary embryogenic structures were transferred to MSWH (MS medium without growth regulators) and SE proliferated by secondary somatic embryogenesis. High morphological heterogeneity was found among cotyledonary SE. However, converted plants looked morphologically normal with well-developed rooting systems and shoots. The genetic stability of the plant material during the somatic embryogenesis process was evaluated by using six to eight nuclear microsatellites transferred from Q. myrsinifolia Blume, Q. petraea (Matts.) Liebl. and Q. robur L. Five of eight microsatellites distinguished among the genotypes analyzed, and for QsG0, QsGM1 and QsGM2, uniform microsatellite patterns were generally observed within and between SE and the respective donor genotypes. For genotype QsG5, the same pattern was observed in all samples analyzed except one, where the mutation percentage was 2.5%. We conclude that microsatellite markers can be used to assess genetic stability of clonal materials and to determine genetic stability throughout the process of somatic embryogenesis. The simple somatic embryogenesis protocol described has potential for the commercial propagation of Q. suber because it results in a low percentage of mutations.

  6. Performance characteristics and long-term calibration stability of a beam monitor for a proton scanning gantry

    Energy Technology Data Exchange (ETDEWEB)

    Nichiporov, D.F., E-mail: nichipor@indiana.ed [Indiana University Cyclotron Facility, 2401 Milo B. Sampson Ln., Bloomington, IN 47408 (United States); Klyachko, A.V.; Solberg, K.A. [Indiana University Cyclotron Facility, 2401 Milo B. Sampson Ln., Bloomington, IN 47408 (United States); Zhao, Q. [Midwest Proton Radiotherapy Institute, 2425 Milo B. Sampson Ln., Bloomington, IN 47408 (United States)

    2011-02-15

    A monitor for a uniformly scanned beam was designed and constructed by the Indiana University Cyclotron Facility for use in a clinical proton gantry at the Midwest Proton Radiotherapy Institute. The beam monitor is a thin-walled, wide-aperture ionization chamber, which provides information about dose, beam size, symmetry, flatness, and position. Several characteristics of the monitor's performance were studied, including linearity in dose rate, reproducibility, recombination correction, and dependence on both radiation field size and gantry angle. Additionally, stability of the detector output was analyzed using daily monitor calibrations performed over a period of 21 months. The beam monitor was found to meet design requirements for linearity ({+-}1%), calibration stability ({+-}2%), and stability of response as a function of gantry angle ({+-}1%). Beam monitor calibration statistics also revealed a sine-like yearly trend with a {+-}2% maximum deviation from the average. These and other beam monitor test results are presented and discussed in the context of the detector design. Design changes aimed at further improving the detector's performance characteristics are proposed.

  7. Interfacial, mechanical properties of Al{sub 2}O{sub 3}-NiAl composites respective to long term thermal stability

    Energy Technology Data Exchange (ETDEWEB)

    Song, Jia; Hu, Weiping; Gottstein, Guenter [RWTH Aachen Univ. (Germany). Inst. of Physical Metallurgy and Metal Physics

    2010-07-01

    The long term thermal stability of NiAl-Al{sub 2}O{sub 3} composites was investigated. During annealing of the composites at 973 K and 1373 K for 2000 hours, the NiAl-Al{sub 2}O{sub 3} system showed excellent chemical stability. However, grain growth and embrittlement progressed in the polycrystalline NiAl matrix. The interfacial shear strength decreased from 222{+-}50 MPa for the as-fabricated sample to 197{+-}48 MPa and 150{+-}38 MPa for the samples annealed at 973 K and 1373 K, respectively. The microstructure change during annealing at 973K and 1373 K affected the tensile strength differently. The potential causes of microstructure and interface structure change and their impact on mechanical properties are discussed. (orig.)

  8. Theory, Investigation and Stability of Cathode Electrocatalytic Activity

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Dong; Liu, Mingfei; Lai, Samson; Blinn, Kevin; Liu, Meilin

    2012-09-30

    The main objective of this project is to systematically characterize the surface composition, morphology, and electro-catalytic properties of catalysts coated on LSCF, aiming to establish the scientific basis for rational design of high-performance cathodes by combining a porous backbone (such as LSCF) with a thin catalyst coating. The understanding gained will help us to optimize the composition and morphology of the catalyst layer and microstructure of the LSCF backbone for better performance. More specifically, the technical objectives include: (1) to characterize the surface composition, morphology, and electro-catalytic properties of catalysts coated on LSCF; (2) to characterize the microscopic details and stability of the LSCF-catalyst (e.g., LSM) interfaces; (3) to establish the scientific basis for rational design of high-performance cathodes by combining a porous backbone (such as LSCF) with a thin catalyst coating; and (4) to demonstrate that the performance and stability of porous LSCF cathodes can be enhanced by the application of a thin-film coating of LSM through a solution infiltration process in small homemade button cells and in commercially available cells of larger dimension. We have successfully developed dense, conformal LSM films with desired structure, composition, morphology, and thickness on the LSCF surfaces by two different infiltration processes: a non-aqueous and a water-based sol-gel process. It is demonstrated that the activity and stability of LSCF cathodes can be improved by the introduction of a thin-film LSM coating through an infiltration process. Surface and interface of the LSM-coated LSCF cathode were systematically characterized using advanced microscopy and spectroscopy techniques. TEM observation suggests that a layer of La and Sr oxide was formed on LSCF surfaces after annealing. With LSM infiltration, in contrast, we no longer observe such La/Sr oxide layer on the LSM-coated LSCF samples after annealing under similar

  9. Viscoelastic gels of guar and xanthan gum mixtures provide long-term stabilization of iron micro- and nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Xue Dingqi [Politecnico di Torino, Dipartimento Scienza Applicata e Tecnologia-DISAT and Dipartimento di Ingegneria dell' Ambiente, del Territorio e delle Infrastrutture-DIATI (Italy); Sethi, Rajandrea, E-mail: rajandrea.sethi@polito.it [Politecnico di Torino, Dipartimento di Ingegneria dell' Ambiente, del Territorio e delle Infrastrutture-DIATI (Italy)

    2012-11-15

    Iron micro- and nanoparticles used for groundwater remediation and medical applications are prone to fast aggregation and sedimentation. Diluted single biopolymer water solutions of guar gum (GG) or xanthan gum (XG) can stabilize these particles for few hours providing steric repulsion and by increasing the viscosity of the suspension. The goal of the study is to demonstrate that amending GG solutions with small amounts of XG (XG/GG weight ratio 1:19; 3 g/L of total biopolymer concentration) can significantly improve the capability of the biopolymer to stabilize highly concentrated iron micro- and nanoparticle suspensions. The synergistic effect between GG and XG generates a viscoelastic gel that can maintain 20 g/L iron particles suspended for over 24 h. This is attributed to (i) an increase in the static viscosity, (ii) a combined polymer structure the yield stress of which contrasts the downward stress exerted by the iron particles, and (iii) the adsorption of the polymers to the iron surface having an anchoring effect on the particles. The XG/GG viscoelastic gel is characterized by a marked shear thinning behavior. This property, coupled with the low biopolymer concentration, determines small viscosity values at high shear rates, facilitating the injection in porous media. Furthermore, the thermosensitivity of the soft elastic polymeric network promotes higher stability and longer storage times at low temperatures and rapid decrease of viscosity at higher temperatures. This feature can be exploited in order to improve the flowability and the delivery of the suspensions to the target as well as to effectively tune and control the release of the iron particles.

  10. Viscoelastic gels of guar and xanthan gum mixtures provide long-term stabilization of iron micro- and nanoparticles

    Science.gov (United States)

    Xue, Dingqi; Sethi, Rajandrea

    2012-11-01

    Iron micro- and nanoparticles used for groundwater remediation and medical applications are prone to fast aggregation and sedimentation. Diluted single biopolymer water solutions of guar gum (GG) or xanthan gum (XG) can stabilize these particles for few hours providing steric repulsion and by increasing the viscosity of the suspension. The goal of the study is to demonstrate that amending GG solutions with small amounts of XG (XG/GG weight ratio 1:19; 3 g/L of total biopolymer concentration) can significantly improve the capability of the biopolymer to stabilize highly concentrated iron micro- and nanoparticle suspensions. The synergistic effect between GG and XG generates a viscoelastic gel that can maintain 20 g/L iron particles suspended for over 24 h. This is attributed to (i) an increase in the static viscosity, (ii) a combined polymer structure the yield stress of which contrasts the downward stress exerted by the iron particles, and (iii) the adsorption of the polymers to the iron surface having an anchoring effect on the particles. The XG/GG viscoelastic gel is characterized by a marked shear thinning behavior. This property, coupled with the low biopolymer concentration, determines small viscosity values at high shear rates, facilitating the injection in porous media. Furthermore, the thermosensitivity of the soft elastic polymeric network promotes higher stability and longer storage times at low temperatures and rapid decrease of viscosity at higher temperatures. This feature can be exploited in order to improve the flowability and the delivery of the suspensions to the target as well as to effectively tune and control the release of the iron particles.

  11. Long-term stability and effective population size in North Sea and Baltic Sea cod ( Gadus morhua )

    DEFF Research Database (Denmark)

    Poulsen, Nina Aagaard; Eg Nielsen, Einar; Schierup, M.H.;

    2006-01-01

    DNA from archived otoliths was used to explore the temporal stability of the genetic composition of two cod populations, the Moray Firth (North Sea) sampled in 1965 and 2002, and the Bornholm Basin (Baltic Sea) sampled in 1928 and 1997. We found no significant changes in the allele frequencies...... for the Moray Firth population, while subtle but significant genetic changes over time were detected for the Bornholm Basin population. Estimates of the effective population size (N-e) generally exceeded 500 for both populations when employing a number of varieties of the temporal genetic method. However...

  12. Comparing the short and long term stability of biodegradable, ceramic and cation exchange membranes in microbial fuel cells.

    Science.gov (United States)

    Winfield, Jonathan; Chambers, Lily D; Rossiter, Jonathan; Ieropoulos, Ioannis

    2013-11-01

    The long and short-term stability of two porous dependent ion exchange materials; starch-based compostable bags (BioBag) and ceramic, were compared to commercially available cation exchange membrane (CEM) in microbial fuel cells. Using bi-directional polarisation methods, CEM exhibited power overshoot during the forward sweep followed by significant power decline over the reverse sweep (38%). The porous membranes displayed no power overshoot with comparably smaller drops in power during the reverse sweep (ceramic 8%, BioBag 5.5%). The total internal resistance at maximum power increased by 64% for CEM compared to 4% (ceramic) and 6% (BioBag). Under fixed external resistive loads, CEM exhibited steeper pH reductions than the porous membranes. Despite its limited lifetime, the BioBag proved an efficient material for a stable microbial environment until failing after 8 months, due to natural degradation. These findings highlight porous separators as ideal candidates for advancing MFC technology in terms of cost and operation stability.

  13. Long-term improvements to photoluminescence and dispersion stability by flowing SDS-SWNT suspensions through microfluidic channels.

    Science.gov (United States)

    Silvera-Batista, Carlos A; Weinberg, Philip; Butler, Jason E; Ziegler, Kirk J

    2009-09-09

    Shearing single-walled carbon nanotubes (SWNTs) coated with sodium dodecyl sulfate in microfluidic channels significantly increases the photoluminescence (PL) intensity and dispersion stability of SWNTs. The PL quantum yield (QY) of SWNTs improves by a factor of 3 for initially bright suspensions; on the other hand, SWNT QYs in a "poor" suspension improve by 2 orders of magnitude. In both cases, the QYs of the sheared suspensions are approximately 1%. The increases in PL intensity persist for months and are most prominent in larger diameter SWNTs. These improvements are attributed to surfactant reorganization rather than disaggregation of SWNTs bundles or shear-induced alignment. The results also highlight potential opportunities to eliminate discrepancies in the PL intensity of different suspensions and further improve the PL of SWNTs by tailoring the surfactant structure around SWNTs.

  14. Simulation of long-term debris flow sediment transport based on a slope stability and a debris flow routing model

    Science.gov (United States)

    Müller, T.; Hoffmann, T.

    2012-04-01

    Debris flows play a crucial role in the coupling of hillslope-sediment sources and channels in mountain environments. In most landscape evolution models (LEMs), the sediment transport by debris flows is (if at all) often represented by simple empirical rules. This generally results from the mismatch of the coarse resolution of the LEMs and the small scale impacts of debris flow processes. To extend the accuracy and predictive power of LEMs, either a higher resolution of LEMs in combination with process-based debris flow models or a better parametrisation of subpixel scale debris flow processes is necessary. Furthermore, the simulation of sediment transport by debris flows is complicated by their episodic nature and unknown factors controlling the frequency and magnitude of events. Here, we present first results using a slope stability model (SINMAP) and an event-based debris flow routing model (SCIDDICA-S4c) to simulate the effects of debris flows in LEMs. The model was implemented in the XULU modelling platform developed by the Department of Computer Science at the University of Bonn. The combination of the slope stability model and the event-based routing and mass balance model enables us to simulate the triggering and routing of debris flow material through the iteration of single events over several thousand years. Although a detailed calibration and validation remains to be done, the resulting debris flow-affected areas in a test elevation model correspond well with data gained from a geomorphological mapping of the corresponding area, justifying our approach. The increased computation speed allows to run high resolution LEM in convenient short time at relatively low cost. This should encourage the development of more detailed LEMs, in which process-based models should be incorporated.

  15. Long-term collections

    CERN Multimedia

    Collectes à long terme

    2007-01-01

    The Committee of the Long Term Collections (CLT) asks for your attention for the following message from a young Peruvian scientist, following the earthquake which devastated part of her country a month ago.

  16. Long-term stability of underground operated CZT detectors based on the analysis of intrinsic {sup 113}Cd β{sup −}-decay

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, J. [Universität Hamburg, Institut für Experimentalphysik, Luruper Chaussee 149, 22761 Hamburg (Germany); Gößling, C. [Technische Universität Dortmund, Lehrstuhl für Experimentelle Physik IV, Otto-Hahn-Str 4, 44221 Dortmund (Germany); Gehre, D., E-mail: daniel.gehre@tu-dresden.de [Technische Universität Dresden, Institut für Kern- und Teilchenphysik, Zellescher Weg 19, 01069 Dresden (Germany); Hagner, C.; Heidrich, N. [Universität Hamburg, Institut für Experimentalphysik, Luruper Chaussee 149, 22761 Hamburg (Germany); Klingenberg, R.; Kröninger, K.; Nitsch, C. [Technische Universität Dortmund, Lehrstuhl für Experimentelle Physik IV, Otto-Hahn-Str 4, 44221 Dortmund (Germany); Oldorf, C. [Universität Hamburg, Institut für Experimentalphysik, Luruper Chaussee 149, 22761 Hamburg (Germany); Quante, T.; Rajek, S. [Technische Universität Dortmund, Lehrstuhl für Experimentelle Physik IV, Otto-Hahn-Str 4, 44221 Dortmund (Germany); Rebber, H.; Rohatsch, K. [Universität Hamburg, Institut für Experimentalphysik, Luruper Chaussee 149, 22761 Hamburg (Germany); Tebrügge, J.; Temminghoff, R.; Theinert, R. [Technische Universität Dortmund, Lehrstuhl für Experimentelle Physik IV, Otto-Hahn-Str 4, 44221 Dortmund (Germany); and others

    2016-06-11

    The COBRA collaboration operates a demonstrator setup at the underground facility Laboratori Nazionali del Gran Sasso (LNGS, located in Italy) to prove the technological capabilities of this concept for the search for neutrinoless double beta-decay. The setup consists of 64 (1×1×1) cm{sup 3} Cadmium-Zinc-Telluride (CZT) detectors in Coplanar-Grid (CPG) configuration. One purpose of this demonstrator is to test if reliable long-term operation of CZT-CPG detectors in such a setup is possible. The demonstrator has been operated under ultra low-background conditions for more than three years and collected data corresponding to a total exposure of 218 kg days. The presented study focuses on the long-term stability of CZT detectors by analyzing the intrinsic, fourfold forbidden non-unique {sup 113}Cd single beta-decay. It can be shown that CZT detectors can be operated stably for long periods of time and that the {sup 113}Cd single beta-decay can be used as an internal monitor of the detector performance during the runtime of the experiment.

  17. Effect of mesogenic ligands on short and long-term spectral dynamics and stability of core-shell CdSe/ZnS quantum dots

    Science.gov (United States)

    Jussi Amaral, Jose; Betady, Edwin; Quint, Makiko T.; Martin, Denzal; Riahinasab, Sheida T.; Hirst, Linda S.; Ghosh, Sayantani

    2016-10-01

    Surface modification is a versatile and effective route towards improving functional and structural characteristics of chemically synthesized nanomaterials. In the specific case of semiconducting nanoparticles (quantum dots (QDs)) the photophysical properties are strongly tied to surface conditions. Therefore, a careful monitoring of photoluminescent (PL) behavior, both short and long term, is critical following alterations to their surface chemistry. We observe several noteworthy changes in the static and dynamic PL spectra of CdSe/ZnS core-shell QDs when the as-grown native ligands are exchanged with two different mesogenic ligands—rod-like molecules attached to the particle by a flexible alkyl chain. These include reduced inter-dot energy transfer, stable recombination rates and steady emission color over more than an hour of continuous photo-excitation, all effects being more prominent in the sample with the longer attachment chain. Temperature dependence of PL and recombination rates reveals further differences. Thermally activated PL recovery threshold is pushed to a higher temperature in the modified dots, while PL lifetime does not show the expected increase with decreasing temperature. Our results indicate that increased charge separation induced by the longer ligands is responsible for these effects, and this may be a route to fabricating QD films for specific applications demanding long term emission color stability.

  18. Artificial-enzyme gel membrane-based biosurveillance sensor with high reproducibility and long-term storage stability.

    Science.gov (United States)

    Ikeno, Shinya; Yoshida, Tetsuya; Haruyama, Tetsuya

    2009-02-01

    We propose that the most sophisticated strategy for primary biosurveillance is to exploit structural commonality through the detection of biologically relevant phosphoric substances. A novel assay, an artificial-enzyme membrane was designed and synthesized for sensor fabrication. This artificial-enzyme catalyzes the hydrolysis of the diphosphoric acid anhydride structure. This structure-selective, albeit not molecule-selective, catalytic hydrolysis was successfully coupled with amperometric detection. Since the catalytic reaction produces a dephosphorylation product (PO(4)(3-)), it can be reduced by an electrode potential of -250 mV vs. Ag/AgCl. Owing to the structural selectivity of the artificial-enzyme membrane, the sensor can detect biological phosphoric substances comprehensively that have the diphosphoric acid anhydride structure. The sensor successfully determined various biological phosphoric substances at concentrations in the micromolar (microM) to millimolar (mM) range, and it showed good functional stability and reproducibility in terms of sensor responses. This sensor was used to detect Escherichia coli lysed by heat treatment, and the response increased with increasing bacterial numbers. This unique technique for analyzing molecular commonality can be applied to the surveillance of biocontaminants, e.g. microorganisms, spores and viruses. Artificial-enzyme-based detection is a novel strategy for practical biosurveillance in the front line.

  19. Long-term reactive transport modelling of stabilized/solidified waste: from dynamic leaching tests to disposal scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Windt, Laurent de [Ecole des Mines de Paris, CG-Hydrodynamics and Reaction Group, 35 R. St-Honore, 77300 Fontainebleau (France)]. E-mail: laurent.dewindt@ensmp.fr; Badreddine, Rabia [INERIS, Direction des Risques Chroniques, Unite Dechets et Sites Pollues, Parc Technologique Alata BP 2, 60550 Verneuil-en-Halatte (France); Lagneau, Vincent [Ecole des Mines de Paris, CG-Hydrodynamics and Reaction Group, 35 R. St-Honore, 77300 Fontainebleau (France)

    2007-01-31

    Environmental impact assessment of hazardous waste disposal relies, among others, on standardized leaching tests characterized by a strong coupling between diffusion and chemical processes. In that respect, this study shows that reactive transport modelling is a useful tool to extrapolate laboratory results to site conditions characterized by lower solution/solid (L/S) ratios, site specific geometry, infiltration, etc. A cement solidified/stabilized (S/S) waste containing lead is investigated as a typical example. The reactive transport model developed in a previous study to simulate the initial state of the waste as well as laboratory batch and dynamic tests is first summarized. Using the same numerical code (HYTEC), this model is then integrated to a simplified waste disposal scenario assuming a defective cover and rain water infiltration. The coupled evolution of the S/S waste chemistry and the pollutant plume migration are modelled assessing the importance of the cracking state of the monolithic waste. The studied configurations correspond to an undamaged and fully sealed system, a few main fractures between undamaged monoliths and, finally, a dense crack-network in the monoliths. The model considers the potential effects of cracking, first the increase of rain water and carbon dioxide infiltration and, secondly, the increase of L/S ratio and reactive surfaces, using either explicit fracture representation or dual porosity approaches.

  20. Long-term spatiotemporal stability and dynamic changes in helminth infracommunities of bank voles (Myodes glareolus) in NE Poland.

    Science.gov (United States)

    Grzybek, Maciej; Bajer, Anna; Bednarska, Małgorzata; Al-Sarraf, Mohammed; Behnke-Borowczyk, Jolanta; Harris, Philip D; Price, Stephen J; Brown, Gabrielle S; Osborne, Sarah-Jane; Siński, Edward; Behnke, Jerzy M

    2015-12-01

    Parasites are considered to be an important selective force in host evolution but ecological studies of host-parasite systems are usually short-term providing only snap-shots of what may be dynamic systems. We have conducted four surveys of helminths of bank voles at three ecologically similar woodland sites in NE Poland, spaced over a period of 11 years, to assess the relative importance of temporal and spatial effects on helminth infracommunities. Some measures of infracommunity structure maintained relative stability: the rank order of prevalence and abundance of Heligmosomum mixtum, Heligmosomoides glareoli and Mastophorus muris changed little between the four surveys. Other measures changed markedly: dynamic changes were evident in Syphacia petrusewiczi which declined to local extinction, while the capillariid Aonchotheca annulosa first appeared in 2002 and then increased in prevalence and abundance over the remaining three surveys. Some species are therefore dynamic and both introductions and extinctions can be expected in ecological time. At higher taxonomic levels and for derived measures, year and host-age effects and their interactions with site are important. Our surveys emphasize that the site of capture is the major determinant of the species contributing to helminth community structure, providing some predictability in these systems.

  1. Long-term stability of mandibular setback surgery: a follow-up of 80 bilateral sagittal split osteotomy patients.

    Science.gov (United States)

    Mobarak, K A; Krogstad, O; Espeland, L; Lyberg, T

    2000-01-01

    The objective of this cephalometric study was to evaluate skeletal stability and time course of postoperative changes in 80 consecutive mandibular prognathism patients operated with bilateral sagittal split osteotomy (BSSO) and rigid fixation. Lateral cephalograms were taken on 6 occasions: immediately preoperative, immediately postoperative, 2 and 6 months postoperative, and 1 and 3 years postoperative. The results indicate that BSSO with rigid fixation for mandibular setback is a fairly stable clinical procedure. Three years after surgery, mean relapse at pogonion represented 26% of the surgical setback (19% at point B). Most of the relapse (72%) took place during the first 6 months after surgery. Clockwise rotation of the ascending ramus at surgery with lengthening of the elevator muscles, though evident in this study and apparently responsible for the early horizontal postoperative changes, does not seem to be associated with marked relapse. Changes occurring in some of the younger patients between 1 and 3 years postoperatively are likely to be manifestations of late mandibular growth.

  2. Improving the long-term stability of PBDTTPD polymer solar cells through material purification aimed at removing organic impurities

    KAUST Repository

    Mateker, William R.

    2013-01-01

    While bulk heterojunction (BHJ) solar cells fabricated from high M n PBDTTPD achieve power conversion efficiencies (PCE) as high as 7.3%, the short-circuit current density (JSC) of these devices can drop by 20% after seven days of storage in the dark and under inert conditions. This degradation is characterized by the appearance of S-shape features in the reverse bias region of current-voltage (J-V) curves that increase in amplitude over time. Conversely, BHJ solar cells fabricated from low Mn PBDTTPD do not develop S-shaped J-V curves. However, S-shapes identical to those observed in high Mn PBDTTPD solar cells can be induced in low M n devices through intentional contamination with the TPD monomer. Furthermore, when high Mn PBDTTPD is purified via size exclusion chromatography (SEC) to reduce the content of low molecular weight species, the JSC of polymer devices is significantly more stable over time. After 111 days of storage in the dark under inert conditions, the J-V curves do not develop S-shapes and the JSC degrades by only 6%. The S-shape degradation feature, symptomatic of low device lifetimes, appears to be linked to the presence of low molecular weight contaminants, which may be trapped within samples of high Mn polymer that have not been purified by SEC. Although these impurities do not affect initial device PCE, they significantly reduce device lifetime, and solar cell stability is improved by increasing the purity of the polymer materials. © 2013 The Royal Society of Chemistry.

  3. Dump stability and soil fertility of a coal mine spoil in Indian dry tropical environment: a long-term study.

    Science.gov (United States)

    Tripathi, Nimisha; Singh, Raj Shekhar; Chaulya, Swadesh K

    2012-10-01

    Plant available nitrogen, belowground (root) biomass, soil nitrogen (N) mineralization and microbial biomass N (MBN) were studied for 12 years at the interval of 2 years (0, 2, 4, 6, 8, 10 and 12 years) and mine dump stability at the intervals of 6 years (0, 6 and 12 years) after re-vegetation on coal mine spoil site. Plant available nitrogen in revegetated mine spoil ranged from 4.51 to 6.59 μg g(-1), net N-mineralization from 1.87 to 13.85 μg g(-1) month(-1), MBN from 10 to 22.63 μg g(-1), and root biomass from 28 to 566 g(-2). Mining activity has caused a change in soil characteristics including plant available nutrients like nitrate-N, ammonium-N and phosphate-P by 70, 67, and 76 %, respectively, N-mineralization by 93 %, root biomass values by 97 % and MBN values by 91 % compared to forest ecosystems. Revegetation of mine spoil produced increase in root biomass values by 1.3, 7.6 and 17.2 times, mineral N values by 1.22, 1.43 and 1.79 times, N-mineralization values by 1.8, 5.2 and 12.6 times and MBN values by 1.6, 2.0, and 3.4 times in 2, 6 and 12 years, respectively. Below ground biomass was highly co-related with microbial biomass and plant available nutrients. N-mineralization, plant available nutrients and the clay content were positively correlated with age of revegetation (P soil fertility status in mine spoil, where plant biomass and microbial biomass provide major contributions in ecological redevelopment of the mine spoil.

  4. Long-term stability assessment of AlGaN/GaN field effect transistors modified with peptides: Device characteristics vs. surface properties

    Energy Technology Data Exchange (ETDEWEB)

    Rohrbaugh, Nathaniel; Bryan, Isaac; Bryan, Zachary; Collazo, Ramon; Ivanisevic, Albena, E-mail: ivanisevic@ncsu.edu [Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695 (United States)

    2015-09-15

    AlGaN/GaN Field Effect Transistors (FETs) are promising biosensing devices. Functionalization of these devices is explored in this study using an in situ approach with phosphoric acid etchant and a phosphonic acid derivative. Devices are terminated on peptides and soaked in water for up to 168 hrs to examine FETs for both device responses and surface chemistry changes. Measurements demonstrated threshold voltage shifting after the functionalization and soaking processes, but demonstrated stable FET behavior throughout. X-ray photoelectron spectroscopy and atomic force microscopy confirmed peptides attachment to device surfaces before and after water soaking. Results of this work point to the stability of peptide coated functionalized AlGaN/GaN devices in solution and support further research of these devices as disposable, long term, in situ biosensors.

  5. Thermal stability and long term hydrogen/deuterium release from soft to hard amorphous carbon layers analyzed using in-situ Raman spectroscopy. Comparison with Tore Supra deposits

    CERN Document Server

    Pardanaud, C; Giacometti, G; Mellet, N; Pégourié, B; Roubin, P

    2015-01-01

    The thermal stability of 200 nm thick plasma enhanced chemical vapor deposited a-C:H and a-C:D layers ranging from soft to hard layers has been studied and compared to that of deposits collected on the Tore Supra tokamak plasma facing components by means of in-situ Raman spectroscopy. Linear ramp heating and long term isotherms (from several minutes to 21 days) have been performed and correlations between spectrometric parameters have been found. The information obtained on the sp 2 clustering has been investigated by comparing the G band shift and the 514 nm photon absorption evolution due to the thermal treatment of the layer. The effects of isotopic substitution have also been investigated.

  6. Ground-based assessment of the bias and long-term stability of 14 limb and occultation ozone profile data records

    Science.gov (United States)

    Hubert, Daan; Lambert, Jean-Christopher; Verhoelst, Tijl; Granville, José; Keppens, Arno; Baray, Jean-Luc; Bourassa, Adam E.; Cortesi, Ugo; Degenstein, Doug A.; Froidevaux, Lucien; Godin-Beekmann, Sophie; Hoppel, Karl W.; Johnson, Bryan J.; Kyrölä, Erkki; Leblanc, Thierry; Lichtenberg, Günter; Marchand, Marion; McElroy, C. Thomas; Murtagh, Donal; Nakane, Hideaki; Portafaix, Thierry; Querel, Richard; Russell, James M., III; Salvador, Jacobo; Smit, Herman G. J.; Stebel, Kerstin; Steinbrecht, Wolfgang; Strawbridge, Kevin B.; Stübi, René; Swart, Daan P. J.; Taha, Ghassan; Tarasick, David W.; Thompson, Anne M.; Urban, Joachim; van Gijsel, Joanna A. E.; Van Malderen, Roeland; von der Gathen, Peter; Walker, Kaley A.; Wolfram, Elian; Zawodny, Joseph M.

    2016-06-01

    profile records of a large number of limb and occultation satellite instruments are widely used to address several key questions in ozone research. Further progress in some domains depends on a more detailed understanding of these data sets, especially of their long-term stability and their mutual consistency. To this end, we made a systematic assessment of 14 limb and occultation sounders that, together, provide more than three decades of global ozone profile measurements. In particular, we considered the latest operational Level-2 records by SAGE II, SAGE III, HALOE, UARS MLS, Aura MLS, POAM II, POAM III, OSIRIS, SMR, GOMOS, MIPAS, SCIAMACHY, ACE-FTS and MAESTRO. Central to our work is a consistent and robust analysis of the comparisons against the ground-based ozonesonde and stratospheric ozone lidar networks. It allowed us to investigate, from the troposphere up to the stratopause, the following main aspects of satellite data quality: long-term stability, overall bias and short-term variability, together with their dependence on geophysical parameters and profile representation. In addition, it permitted us to quantify the overall consistency between the ozone profilers. Generally, we found that between 20 and 40 km the satellite ozone measurement biases are smaller than ±5 %, the short-term variabilities are less than 5-12 % and the drifts are at most ±5 % decade-1 (or even ±3 % decade-1 for a few records). The agreement with ground-based data degrades somewhat towards the stratopause and especially towards the tropopause where natural variability and low ozone abundances impede a more precise analysis. In part of the stratosphere a few records deviate from the preceding general conclusions; we identified biases of 10 % and more (POAM II and SCIAMACHY), markedly higher single-profile variability (SMR and SCIAMACHY) and significant long-term drifts (SCIAMACHY, OSIRIS, HALOE and possibly GOMOS and SMR as well). Furthermore, we reflected on the repercussions

  7. Long-term efficiency and stability of wetlands for treating wastewater of a lead/zinc mine and the concurrent ecosystem development

    Energy Technology Data Exchange (ETDEWEB)

    Yang, B. [School of Life Sciences, and State Key Laboratory of Biocontrol, Sun Yat-Sen (Zhongshan) University, Guangzhou 510275 (China); Lan, C.Y. [School of Life Sciences, and State Key Laboratory of Biocontrol, Sun Yat-Sen (Zhongshan) University, Guangzhou 510275 (China); Yang, C.S. [School of Life Sciences, and State Key Laboratory of Biocontrol, Sun Yat-Sen (Zhongshan) University, Guangzhou 510275 (China); College of Golf, Shenzhen University, Shenzhen 518060 (China); Liao, W.B. [School of Life Sciences, and State Key Laboratory of Biocontrol, Sun Yat-Sen (Zhongshan) University, Guangzhou 510275 (China); Chang, H. [School of Life Sciences, and State Key Laboratory of Biocontrol, Sun Yat-Sen (Zhongshan) University, Guangzhou 510275 (China); Shu, W.S. [School of Life Sciences, and State Key Laboratory of Biocontrol, Sun Yat-Sen (Zhongshan) University, Guangzhou 510275 (China)]. E-mail: ls53@zsu.edu.cn

    2006-10-15

    A constructed wetland system in Guangdong Province, South of China has been used for treating Pb/Zn mine discharge since 1985. The performance in the purification of the mine discharge and the concurrent ecosystem development within the system during the period of 1985-2000 has been studied. The untreated wastewater contained rather high concentrations of cadmium (Cd) (0.05 mg L{sup -1}), lead (Pb) (11.5 mg L{sup -1}), and zinc (Zn) (14.5 mg L{sup -1}), which greatly exceed the upper limits for industrial wastewater discharge in China. The constructed wetland system effectively removed Cd by 94.00%, Pb by 99.04%, Zn by 97.30%, and total suspended solids (TSS) by 98.95% from the mine discharge over a long period (over 16 years) leading to significant improvement in water quality; it was also found that there were no significantly annual or monthly variations in pH values, As, Cd, Hg, Pb, and Zn concentrations in water collected from the outlet of the wetland. Moreover, diversity and abundance of living organisms, including protozoan, higher plants, terrestrial animals, and birds, increased gradually. The 16-year monitoring results showed a reciprocal relationship, at a certain extent, between restoration of the wetland ecosystem, in other words, the maturity of the wetland, and the long-term efficiency and stability on purifying heavy metal-contaminated wastewater. - Relationship between the maturity of a constructed wetland and the long-term efficiency and stability of purifying heavy metal-contaminated wastewater.

  8. Investigation of ionic conductivity and long-term stability of a LiI and KI coupled diphenylamine quasi-solid-state dye-sensitized solar cell.

    Science.gov (United States)

    Agarwala, S; Peh, C K N; Ho, G W

    2011-07-01

    In this work, enhancement of ionic conductivity and long-term stability through the addition of diphenylamine (DPA) in poly(ethylene oxide) (PEO) is demonstrated. Potassium iodide (KI) is adopted as the crystal growth inhibitor, and DPA is used as a charge transport enhancer in the electrolyte. The modified electrolyte is used with titanium dioxide (TiO2) nanoparticles, which is systematically tuned to obtain high surface area. The dye-sensitized solar cell (DSSC) showed a photocurrent of 14 mAcm2 with a total conversion efficiency of 5.8% under one sun irradiation. DPA enhances the interaction of the TiO2 nanoparticle film and the I-/I3- electrolyte leading to high ionic conductivity (3.5 × 10-3 Scm-1), without compromising on the electrochemical and mechanical stability. Electrochemical impedance spectroscopy (EIS) studies show that electron transport and electron lifetime are enhanced in the DPA added electrolyte due to reduced sublimation of iodine. The most promising feature of the electrolyte is increased device stability with 89% of the overall efficiency preserved even after 40 days.

  9. Long-term rice cultivation stabilizes soil organic carbon and promotes soil microbial activity in a salt marsh derived soil chronosequence.

    Science.gov (United States)

    Wang, Ping; Liu, Yalong; Li, Lianqing; Cheng, Kun; Zheng, Jufeng; Zhang, Xuhui; Zheng, Jinwei; Joseph, Stephen; Pan, Genxing

    2015-10-27

    Soil organic carbon (SOC) sequestration with enhanced stable carbon storage has been widely accepted as a very important ecosystem property. Yet, the link between carbon stability and bio-activity for ecosystem functioning with OC accumulation in field soils has not been characterized. We assessed the changes in microbial activity versus carbon stability along a paddy soil chronosequence shifting from salt marsh in East China. We used mean weight diameter, normalized enzyme activity (NEA) and carbon gain from straw amendment for addressing soil aggregation, microbial biochemical activity and potential C sequestration, respectively. In addition, a response ratio was employed to infer the changes in all analyzed parameters with prolonged rice cultivation. While stable carbon pools varied with total SOC accumulation, soil respiration and both bacterial and fungal diversity were relatively constant in the rice soils. Bacterial abundance and NEA were positively but highly correlated to total SOC accumulation, indicating an enhanced bio-activity with carbon stabilization. This could be linked to an enhancement of particulate organic carbon pool due to physical protection with enhanced soil aggregation in the rice soils under long-term rice cultivation. However, the mechanism underpinning these changes should be explored in future studies in rice soils where dynamic redox conditions exist.

  10. Investigation of a methanol reformer concept considering the particular impact of dynamics and long-term stability for use in a fuel-cell-powered passenger car

    Science.gov (United States)

    Peters, R.; Düsterwald, H. G.; Höhlein, B.

    A methanol reformer concept including a reformer, a catalytic burner, a gas cleaning unit, a PEMFC and an electric motor for use in fuel-cell-powered passenger cars was investigated. Special emphasis was placed on the dynamics and the long-term stability of the reformer. Experiments on a laboratory scale were performed in a methanol steam reformer consisting of four different reactor tubes, which were separately balanced. Due to the endothermy of the steam reforming reaction of methanol, a sharp drop in the reaction temperature of about 50 K occurs at the beginning of the catalyst bed. This agrees well with the high catalytic activity at the entrance of the catalyst bed. Forty-five percent of the methanol was converted within the first 10 cm of the catalyst bed where 12.6 g of the CuO/ZnO catalyst was located. Furthermore, CO formation during methanol steam reforming strongly depends on methanol conversion. Long-term measurements for more than 700 h show that the active reaction zone moved through the catalyst bed. Calculations, on the basis of these experiments, revealed that 63 g of reforming catalyst was necessary for mobile PEMFC applications, in this case for 400 W el at a system efficiency of 42% and a theoretical specific hydrogen production of 5.2 m 3n/(h kg Cat). This amount of catalyst was assumed to maintain a hydrogen production of at least 80% of the original amount over an operating range of 3864 h. Cycled start-up and shut-down processes of the methanol steam reformer under nitrogen and hydrogen atmospheres did not harm the catalytic activity. The simulation of the breakdown of the heating system, in which a liquid water/methanol mixture was in close contact with the catalyst, did not reveal any deactivation of the catalytic activity.

  11. Long-Term Collections

    CERN Multimedia

    Comité des collectes à long terme

    2011-01-01

    It is the time of the year when our fireman colleagues go around the laboratory for their traditional calendars sale. A part of the money of the sales will be donated in favour of the long-term collections. We hope that you will welcome them warmly.

  12. Long-term cycle stability at a high current for nanocrystalline LiFePO4 coated with a conductive polymer

    Science.gov (United States)

    Dinh, Hung-Cuong; Lim, Hanjo; Park, Ki Dong; Yeo, In-Hyeong; Kang, Yongku; Mho, Sun-il

    2013-03-01

    Highly uniform hierarchical-microstructured LiFePO4 particles with dumbbell- and donut-shape and individual LiFePO4 nanocrystals were prepared by a hydrothermal method utilizing citric acid or a triblock copolymer (Pluronic P123) as a surfactant. The cathode composed of the individual nanocrystalline LiFePO4 particles exhibited higher specific capacity than the cathodes composed of the hierarchically assembled microparticles. Coating a conductive polymer, poly-3,4-ethylenedioxythiophene (PEDOT), on the surface of LiFePO4 particles improved the battery performances such as large specific capacities, high rate capability and an improved cycle stability. The nanocrystalline LiFePO4 particles coated with PEDOT (20 wt%) exhibited the highest discharge capacities of 175 and 136 mAh g-1 for the first battery cycle and 163 and 128 mAh g-1 after 500 battery cycles, with a degradation rate of 6-7%, at the rates of 1 and 10 C, respectively.

  13. The effect of microwave pretreatment of seeds on the stability and degradation kinetics of phenolic compounds in rapeseed oil during long-term storage.

    Science.gov (United States)

    Rękas, Agnieszka; Ścibisz, Iwona; Siger, Aleksander; Wroniak, Małgorzata

    2017-05-01

    Storage stability and degradation kinetics of phenolic compounds in rapeseed oil pressed from microwave treated seeds (0, 2, 4, 6, 8, 10min, 800W) during long-term storage (12months) at a temperature of 20°C was discussed in the current study. The dominant phenolic compound detected in rapeseed oil was canolol, followed by minor amounts of free phenolic acids and sinapine. The most pronounced effect of seeds microwaving was noted for canolol formation - after 10-min exposure the quantity of this compound was approximately 63-fold higher than in control oil. The degradation of phenolics during storage displayed pseudo first-order kinetics. Differences in the initial degradation rate (r0) demonstrated significant impact of the period of seeds microwave exposure on the degradation rates of phenolic compounds. Results of the half-life calculation (t1/2) showed that the storage stability of phenolic compounds was higher in oils produced from microwave treated rapeseeds than in control oil.

  14. Long-term environmental stability of residual stress of SiN{sub x}, SiO{sub x}, and Ge thin films prepared at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Martyniuk, M. [School of Electrical, Electronic and Computer Engineering, University of Western Australia, Crawley, WA 6009 (Australia)], E-mail: mariusz@ee.uwa.edu.au; Musca, C.A.; Dell, J.M.; Faraone, L. [School of Electrical, Electronic and Computer Engineering, University of Western Australia, Crawley, WA 6009 (Australia)

    2009-06-25

    Optical measurements of thin-film-stress-induced substrate bending have been employed in a characterization of long-term environmental stability of stress of low-temperature (<125 deg. C) plasma enhanced vapor deposited (PECVD) SiN{sub x}, as well as thermally evaporated SiO{sub x}, and Ge thin films for applications in micro-electro-mechanical systems (MEMS) fabricated on temperature sensitive, non-standard substrates. It has been found that in comparison to their stress values measured at atmospheric conditions, PECVD SiN{sub x} layers prepared below {approx}100 deg. C as well as layers of thermally evaporated Ge exhibit significantly more tensile (less compressive) stress values when measured in vacuum, which are reversible upon re-exposure to an atmospheric, dry nitrogen, helium, argon, or oxygen ambient. Raising the deposition temperature above {approx}100 deg. C results in PECVD SiN{sub x} stress being stable in vacuum and dry nitrogen storage, which is complemented by stress stability in laboratory atmosphere for films deposited above {approx}125 deg. C. Stress of thermally evaporated SiO{sub x} layers is stable in vacuum and undergoes compressive stress development in either dry nitrogen or laboratory air.

  15. A long-term frequency-stabilized erbium-fiber-laser-based optical frequency comb with an intra-cavity electro-optic modulator

    CERN Document Server

    Zhang, Y; Zhao, W; Meng, S; Fan, S; Zhang, L; Guo, G; Zhang, S; Jiang, H

    2014-01-01

    We demonstrate a home-made optical frequency comb based on an erbium-doped-fiber femtosecond laser with a ring cavity. The repetition rate of the laser is about 209 MHz determined by optical length of the laser cavity. By controlling an intra-cavity electro-optic modulator and a Piezo-transducer, the repetition rate can be stabilized with megahertz bandwidth in a range of 3 kilohertz, enabling long-term repetition rate phase-locking. The in-loop frequency instability of the repetition rate, limited by measurement system, is 1.3E-13 at 1 second integration time and inversely proportional to integration time for short terms. Using a common path f-2f interferometer, the carrier envelope offset (CEO) frequency of the frequency comb is obtained with a signal-to-noise ratio of 40 dB for 3 megahertz resolution spectrum. Stabilized CEO frequency exhibits a deviation of 0.6 milihertz at 1 second integration time.

  16. Long-Term Stability of New Co-Amorphous Drug Binary Systems: Study of Glass Transitions as a Function of Composition and Shelf Time

    Directory of Open Access Journals (Sweden)

    Luz María Martínez

    2016-12-01

    Full Text Available The amorphous state is of particular interest in the pharmaceutical industry due to the higher solubility that amorphous active pharmaceutical ingredients show compared to their respective crystalline forms. Due to their thermodynamic instability, drugs in the amorphous state tend to recrystallize; in order to avoid crystallization, it has been a common strategy to add a second component to hinder the crystalline state and form a thermally stable co-amorphous system, that is to say, an amorphous binary system which retains its amorphous structure. The second component can be a small molecule excipient (such as a sugar or an aminoacid or a second drug, with the advantage that a second active pharmaceutical ingredient could be used for complementary or combined therapeutic purposes. In most cases, the compositions studied are limited to 1:1, 2:1 and 1:2 molar ratios, leaving a gap of information about phase transitions and stability on the amorphous state in a wider range of compositions. In the present work, a study of novel co–amorphous formulations in which the selection of the active pharmaceutical ingredients was made according to the therapeutic effect is presented. Resistance against crystallization and behavior of glass transition temperature ( T g were studied through calorimetric measurements as a function of composition and shelf time. It was found that binary formulations with T g temperatures higher than those of pure components presented long-term thermal stability. In addition, significant increments of T g values, of as much as 15 ∘ C, were detected as a result of glass relaxation at room temperature during storage time; this behavior of glass transition has not been previously reported for co-amorphous drugs. Based on these results, it can be concluded that monitoring behavior of T g and relaxation processes during the first weeks of storage leads to a more objective evaluation of the thermomechanical stability of an amorphous

  17. Long-Term Stability of New Co-Amorphous Drug Binary Systems: Study of Glass Transitions as a Function of Composition and Shelf Time.

    Science.gov (United States)

    Martínez, Luz María; Videa, Marcelo; Sosa, Nahida González; Ramírez, José Héctor; Castro, Samuel

    2016-12-14

    The amorphous state is of particular interest in the pharmaceutical industry due to the higher solubility that amorphous active pharmaceutical ingredients show compared to their respective crystalline forms. Due to their thermodynamic instability, drugs in the amorphous state tend to recrystallize; in order to avoid crystallization, it has been a common strategy to add a second component to hinder the crystalline state and form a thermally stable co-amorphous system, that is to say, an amorphous binary system which retains its amorphous structure. The second component can be a small molecule excipient (such as a sugar or an aminoacid) or a second drug, with the advantage that a second active pharmaceutical ingredient could be used for complementary or combined therapeutic purposes. In most cases, the compositions studied are limited to 1:1, 2:1 and 1:2 molar ratios, leaving a gap of information about phase transitions and stability on the amorphous state in a wider range of compositions. In the present work, a study of novel co-amorphous formulations in which the selection of the active pharmaceutical ingredients was made according to the therapeutic effect is presented. Resistance against crystallization and behavior of glass transition temperature ( T g were studied through calorimetric measurements as a function of composition and shelf time. It was found that binary formulations with T g temperatures higher than those of pure components presented long-term thermal stability. In addition, significant increments of T g values, of as much as 15 ∘ C, were detected as a result of glass relaxation at room temperature during storage time; this behavior of glass transition has not been previously reported for co-amorphous drugs. Based on these results, it can be concluded that monitoring behavior of T g and relaxation processes during the first weeks of storage leads to a more objective evaluation of the thermomechanical stability of an amorphous formulation.

  18. Quercetin and isorhamnetin glycosides in onion (Allium cepa L.): varietal comparison, physical distribution, coproduct evaluation, and long-term storage stability.

    Science.gov (United States)

    Lee, Jihyun; Mitchell, Alyson E

    2011-02-09

    During onion processing, the outer dried protective layer (outer paper layer) and first two fleshy leaf layers are removed. This coproduct material is a potential commercial source of flavonoids especially quercetin. In the following study, the flavonoid composition was determined in coproduct materials and the press cake (material generated after juice extraction) in several commercially important onion varieties grown in California. Flavonoids were characterized and quantified using LC-(ESI)MS/MS and HPLC. The long-term stability of quercetin glycosides was assessed in dried coproduct materials stored at 4 and 22 °C over a 12 month period. In all varieties, the predominant forms of quercetin were the quercetin 3,4'-O-glucoside and 4'-O-glucoside. The first layer had significantly higher levels of flavonoids than the outer paper, second, and inner flesh layers on a DW basis (p < 0.05). Allium cepa "Milestone" contained the highest levels (p < 0.05) of flavonoids (1703 mg/100 g on a dry weight basis (DW). Onion press cake had significantly higher levels of total quercetin as compared with fresh onions (p < 0.05). The levels of 4'-O-glucoside significantly decreased during the first month of storage and remained stable for 12 months of storage at either 4 or 22 °C (p < 0.05).

  19. Stability of Virgin Olive Oil Phenolic Compounds during Long-Term Storage (18 Months) at Temperatures of 5-50 °C.

    Science.gov (United States)

    Krichene, Dhouha; Salvador, María Desamparados; Fregapane, Giuseppe

    2015-08-05

    Virgin olive oil (VOO) phenolic compounds have high nutritional and biological properties. The purpose of this research was to study the stability of VOO phenolic compounds during long-term storage (18 months) at different temperatures (5, 15, 25, and 50 °C) and to verify the advantage of storing VOO at a temperature lower than the usual commercial conditions (20-25 °C). Four monovarietal VOOs that differed in their fatty acid profile and content of natural antioxidants were used in this study. The degradation of secoiridoid phenolics during storage displayed pseudo-first-order kinetics and depended on the initial content of phenolics related to olive oil variety. The initial degradation rate was similar at 5 and 15 °C but increased considerably at 25 °C and was even faster at 50 °C. Tyrosol derivatives were more stable than hydroxytyrosol compounds, especially in closed bottles with limited oxygen availability. The increase in the content of simple phenolics, the decrease of their secoiridoid derivatives, or the ratio of simple to secoiridoid phenolics could be used as indices of the oxidative and hydrolytic degradation of VOO phenolics. The shelf life of the studied VOO was considerably extended at reduced storage temperature (15 vs 25 °C). Moreover, storage conditions affected VOO phenolic content and therefore the expiration date of the health claim that olive oil polyphenols contribute to the protection of blood lipids from oxidative stress.

  20. [Effect of Long-term Fertilizer Application on the Stability of Organic Carbon in Particle Size Fractions of a Paddy Soil in Zhejiang Province, China].

    Science.gov (United States)

    Mao, Xia-li; Lu, Kou-ping; Sun, Tao; Zhang, Xiao-kai; He, Li-zhi; Wang, Hai-long

    2015-05-01

    Effects of chemical fertilizers and organic manure on the soil organic carbon (SOC) content in particle size fractions of paddy soil were investigated in a 17-year long-term fertilization field experiment in Zhejiang Province, China. The inherent chemical composition of silt- and clay-associated SOC was evaluated with solid-state 13C-NMR spectroscopy. Compared to CK (no fertilizer treatment), NPKRS (NPK fertilizers plus rice straw) , NPKOM (NPK fertilizers plus organic manure) , NPK (NPK fertilizers) and OM (organic manure alone) treatments significantly (P fertilizers alone, combined application of organic amendments and NPK fertilizers facilitated the storage of newly sequestered SOC in silt- and clay-sized fractions, which could be more conducive to the stability of SOC. Based on 13C-NMR spectra, both silt and clay fractions were composed of Alkyl-C, O-alkyl-C, Aromatic-C and carbonyl-C. Changes in the relative proportion of different C species were observed between silt and clay fractions: the clay fraction had relatively more Alkyl-C, carbonyl-C and less O-alkyl-C, Aromatic-C than those in the silt fraction. This might be ascribed to the fact that the organic matter complexed with clay was dominated by microbial products, whereas the silt appeared to be rich in aromatic residues derived from plants. The spectra also showed that the relative proportion of different C species was modified by fertilization practices. In comparison with organic amendments alone, the relative proportion of Alkyl-C was decreased by 9.1%-11.9% and 13.7%-19.9% under combined application of organic amendments and chemical fertilizers, for silt and clay, respectively, and that of O-alkyl-C was increased by 2.9%-6.3% and 13.4%-22.1%, respectively. These results indicated that NPKOM and NPKRS treatments reduced the decomposition rate of SOC. The aromaticity, hydrophobicity and, hence, chemical recalcitrance of silt- and clay-associated SOC in the NPK fertilizer treatments were lower than

  1. Long-Term Collections

    CERN Multimedia

    Staff Association

    2016-01-01

    45 years helping in developing countries! CERN personnel have been helping the least fortunate people on the planet since 1971. How? With the Long-Term Collections! Dear Colleagues, The Staff Association’s Long-Term Collections (LTC) Committee is delighted to share this important milestone in the life of our Laboratory with you. Indeed, whilst the name of CERN is known worldwide for scientific discoveries, it also shines in the many humanitarian projects which have been supported by the LTC since 1971. Several schools and clinics, far and wide, carry its logo... Over the past 45 years, 74 projects have been supported (9 of which are still ongoing). This all came from a group of colleagues who wanted to share a little of what life offered them here at CERN, in this haven of mutual understanding, peace and security, with those who were less fortunate elsewhere. Thus, the LTC were born... Since then, we have worked as a team to maintain the dream of these visionaries, with the help of regular donat...

  2. Long-Term Collection

    CERN Multimedia

    Staff Association

    2016-01-01

    Dear Colleagues, As previously announced in Echo (No. 254), your delegates took action to draw attention to the projects of the Long-Term Collections (LTC), the humanitarian body of the CERN Staff Association. On Tuesday, 11 October, at noon, small Z-Cards were widely distributed at the entrances of CERN restaurants and we thank you all for your interest. We hope to have achieved an important part of our goal, which was to inform you, convince you and find new supporters among you. We will find out in the next few days! An exhibition of the LTC was also set up in the Main Building for the entire week. The Staff Association wants to celebrate the occasion of the Long-Term Collection’s 45th anniversary at CERN because, ever since 1971, CERN personnel have showed great support in helping the least fortunate people on the planet in a variety of ways according to their needs. On a regular basis, joint fundraising appeals are made with the Directorate to help the victims of natural disasters around th...

  3. Collectes à long terme

    CERN Document Server

    Collectes à long terme

    2014-01-01

    En cette fin d’année 2014 qui approche à grands pas, le Comité des Collectes à Long Terme remercie chaleureusement ses fidèles donatrices et donateurs réguliers pour leurs contributions à nos actions en faveur des plus démunis de notre planète. C’est très important, pour notre Comité, de pouvoir compter sur l’appui assidu que vous nous apportez. Depuis plus de 40 ans maintenant, le modèle des CLT est basé principalement sur des actions à long terme (soit une aide pendant 4-5 ans par projet, mais plus parfois selon les circonstances), et sa planification demande une grande régularité de ses soutiens financiers. Grand MERCI à vous ! D’autres dons nous parviennent au cours de l’année, et ils sont aussi les bienvenus. En particulier, nous tenons à remercier...

  4. Setting a chronology for the basal ice at Dye-3 and GRIP: Implications for the long-term stability of the Greenland Ice Sheet

    Science.gov (United States)

    Yau, Audrey M.; Bender, Michael L.; Blunier, Thomas; Jouzel, Jean

    2016-10-01

    The long-term stability of the Greenland Ice Sheet (GIS) is an important issue in our understanding of the climate system. Limited data suggest that the northern and southern sections extend well back into the Pleistocene, but most age constraints do not definitively date the ice. Here, we re-examine the GRIP and Dye-3 ice cores to provide direct ice core observations as to whether the GIS survived previous interglacials known to be warmer (˜130 ka) or longer (˜430 ka) than the present interglacial. We present geochemical analyses of the basal ice from Dye-3 (1991-2035 m) and GRIP (3020-3026 m) that characterize and date the ice. We analyzed the elemental and isotopic composition of O2, N2, and Ar, of trapped air in these two cores to assess the origin of trapped gases in silty ice. Dating of the trapped air was then achieved by measuring the paleoatmospheric δ40Ar/38Ar and the 17O anomaly (17Δ) of O2. The resulting age is a lower limit because the trapped air may be contaminated with crustal radiogenic 40Ar. The oldest average age of replicates measured at various depths is 970 ± 140 ka for the GRIP ice core and 400 ka ± 170 ka for Dye-3. 17Δ data from Dye-3 also argue strongly that basal ice in this core predates the Eemian. This confirms that the Greenland Ice Sheet did not completely melt at Southern Greenland during the last interglacial, nor did it completely melt at Summit Greenland during the unusually long interglacial ˜430 kyr before present.

  5. Geologic processes in the RWMC area, Idaho National Engineering Laboratory: Implications for long term stability and soil erosion at the radioactive waste management complex

    Energy Technology Data Exchange (ETDEWEB)

    Hackett, W.R.; Tullis, J.A.; Smith, R.P. [and others

    1995-09-01

    The Radioactive Waste Management Complex (RWMC) is the disposal and storage facility for low-level radioactive waste at the Idaho National Engineering Laboratory (INEL). Transuranic waste and mixed wastes were also disposed at the RWMC until 1970. It is located in the southwestern part of the INEL about 80 km west of Idaho Falls, Idaho. The INEL occupies a portion of the Eastern Snake River Plain (ESRP), a low-relief, basalt, and sediment-floored basin within the northern Rocky Mountains and northeastern Basin and Range Province. It is a cool and semiarid, sagebrush steppe desert characterized by irregular, rolling terrain. The RWMC began disposal of INEL-generated wastes in 1952, and since 1954, wastes have been accepted from other Federal facilities. Much of the waste is buried in shallow trenches, pits, and soil vaults. Until about 1970, trenches and pits were excavated to the basalt surface, leaving no sediments between the waste and the top of the basalt. Since 1970, a layer of sediment (about 1 m) has been left between the waste and the basalt. The United States Department of Energy (DOE) has developed regulations specific to radioactive-waste disposal, including environmental standards and performance objectives. The regulation applicable to all DOE facilities is DOE Order 5820.2A (Radioactive Waste Management). An important consideration for the performance assessment of the RWMC is the long-term geomorphic stability of the site. Several investigators have identified geologic processes and events that could disrupt a radioactive waste disposal facility. Examples of these {open_quotes}geomorphic hazards{close_quotes} include changes in stream discharge, sediment load, and base level, which may result from climate change, tectonic processes, or magmatic processes. In the performance assessment, these hazards are incorporated into scenarios that may affect the future performance of the RWMC.

  6. Cluster-based comparison of the peptide mass fingerprint obtained by MALDI-TOF mass spectrometry. A case study: long-term stability of rituximab.

    Science.gov (United States)

    Villacorta, Pablo J; Salmerón-García, Antonio; Pelta, David A; Cabeza, José; Lario, Antonio; Navas, Natalia

    2015-03-07

    We evaluated the use of the peptide mass fingerprint (PMF) obtained by matrix assisted laser desorption and ionization (MALDI) time-of-flight mass spectrometry (TOF-MS) to track changes in the structure of a protein. The first problem we had to overcome was the inherent complexity of the PMF, which makes it difficult to compare. We dealt with this problem by developing a cluster-based comparison algorithm which takes into account the proportional error made by the mass spectrometer. This procedure involves grouping together similar masses in an intelligent manner, so that we can determine which data correspond to the same peptide (any slight differences can be explained as experimental errors), and which of them are too different and thus more likely to represent different peptides. The proposed algorithm was applied to track changes in a commercially available monoclonal antibody (mAb), namely rituximab (RTX), prepared under the usual hospital conditions and stored refrigerated (4 °C) and frozen (-20 °C) for a long term study. PMFs were obtained periodically over three months. For each checked time, five replicates of the PMFs were obtained in order to evaluate the similarities between them by means of the occurrences of the particular peptides (m/z). After applying the algorithm to the PMF, different approaches were used to analyse the results. Surprisingly, all of them suggested that there were no differences between the two storage conditions tested, i.e. the RTX samples were almost equally well preserved when stored refrigerated at 4 °C or frozen at -20 °C. The cluster-based methodology is new in protein mass spectrometry and could be useful as an easy test for major changes in proteins and biopharmaceutics for diverse applications in industry and other fields, and could provide additional stability data in relation to the practical use of anticancer drugs.

  7. Long-term skeletal stability after maxillary advancement with distraction osteogenesis using a rigid external distraction device in cleft maxillary deformities.

    Science.gov (United States)

    Figueroa, Alvaro A; Polley, John W; Friede, Hans; Ko, Ellen W

    2004-11-01

    Rigid external distraction is a highly effective technique for correction of maxillary hypoplasia in patients with orofacial clefts. The clinical results after correction of sagittal maxillary deformities in both the adult and pediatric age groups have been stable. The purpose of this retrospective longitudinal cephalometric study was to review the long-term stability of the repositioned maxilla in cleft patients who underwent maxillary advancement with rigid external distraction. Between April 1, 1995, and April 1, 1999, 17 consecutive patients with cleft maxillary hypoplasia underwent maxillary advancement using rigid external distraction. There were 13 male patients and four female patients, with ages ranging from 5.2 to 23.6 years (mean, 12.6 years). After a modified complete high Le Fort I osteotomy and a latency period of 3 to 5 days, patients underwent maxillary advancement with rigid external distraction until proper facial convexity and dental overjet and overbite were obtained. After active distraction, a 3- to 4-week period of rigid retention was undertaken; this was followed by removable elastic retention for 6 to 8 weeks using, during sleep time, an orthodontic protraction face mask. Cephalometric radiographs were obtained preoperatively, after distraction, at 1 year after distraction, and 2 or more years after distraction. The mean follow-up was 3.3 years (minimum, 2.1 years; maximum, 5.3 years). The following measurements were obtained in each cephalogram: three linear horizontal and two linear vertical maxillary measurements, two angular craniomaxillary measurements, and one craniomandibular measurement. Differences between the preoperative and postoperative cephalometric values were analyzed by paired t tests (p mandibular plane angle opened 1.2 degrees after surgery. After the 1- to 3-year follow-up period, the maxilla was stable in the sagittal plane. Minimal anteroposterior growth was observed in the maxilla compared with that exhibited in the

  8. Changes in carbon stability and microbial activity in size fractions of micro-aggregates in a rice soil chronosequence under long term rice cultivation

    Science.gov (United States)

    Pan, Genxing; Liu, Yalong; Wang, Ping; Li, Lianqinfg; Cheng, Kun; Zheng, Jufeng; Zhang, Xuhui; Zheng, Jinwei; Bian, Rongjun; Ding, Yuanjun; Ma, Chong

    2016-04-01

    higher in silt fraction than in other fractions for these rice soils. For the size fractions other than clay fraction, soil gene concentration, Archaeal gen abundance, normalized enzyme activity and carbon sequestration was seen increased but SOC- and gene- scaled soil respiration decreased, more or less with prolonged rice cultivation. As shown with regression analysis, SOC content was positively linearly correlated to recalcitrant carbon proportion but negatively linearly correlated to labile carbon, in both sand and clay fractions. However, soil respiration was found positively logarithmically correlated to total DNA contents and bacterial gen abundance in both sand and clay fractions. Total DNA content was found positively correlated to SOC and labile carbon content, recalcitrant carbon proportion and normalized enzyme activity but negatively to soil respiration, in sand fraction only. Our findings suggested that carbon accumulation and stabilization was prevalent in both sand and clay fraction, only the coarse sand fraction was found responsible for bioactivity dynamics in the rice soils. Thus, soil carbon sequestration was primarily by formation of the macro-aggregates, which again mediated carbon stability and bioactivity in the rice soils under long term rice cultivation.

  9. LONG TERM COLLECTIONS

    CERN Multimedia

    STAFF ASSOCIATION

    2010-01-01

    ACKNOWLEDGMENTS The Long-Term Collections (CLT) committee would like to warmly thank its faithful donors who, year after year, support our actions all over the world. Without you, all this would not be possible. We would like to thank, in particular, the CERN Firemen’s Association who donated 5000 CHF in the spring thanks to the sale of their traditional calendar, and the generosity of the CERN community. A huge thank you to the firemen for their devotion to our cause. And thank you to all those who have opened their door, their heart, and their purses! Similarly, we warmly thank the CERN Yoga Club once again for its wonderful donation of 2000 CHF we recently received. We would also like to tell you that all our projects are running well. Just to remind you, we are currently supporting the activities of the «Réflexe-Partage» Association in Mali; the training centre of «Education et Développement» in Abomey, Benin; and the orphanage and ...

  10. A short-term antihypertensive treatment-induced fall in glomerular filtration rate predicts long-term stability of renal function

    NARCIS (Netherlands)

    Apperloo, AJ; deZeeuw, D; deJong, PE

    1997-01-01

    In long-term intervention studies on renal function outcome an initial decline in the glomerular filtration rate (GFR) may occur after starting therapy. If this initial GFR decline is the result of a treatment-induced hemodynamic change reflecting a fall in intraglomerular pressure, it should be rev

  11. K-wire position in tension-band wiring technique affects stability of wires and long-term outcome in surgical treatment of olecranon fractures.

    NARCIS (Netherlands)

    Linden, S.C. van der; Kampen, A. van; Jaarsma, R.L.

    2012-01-01

    BACKGROUND: Tension-band wiring (TBW) has been accepted as the treatment of choice for displaced olecranon fractures. The aim of this study was to examine the effect of K-wire position on instability of the K-wires in relation to local complications and radiological and clinical long-term outcome. M

  12. The Adults in the Making Program: Long-Term Protective Stabilizing Effects on Alcohol Use and Substance Use Problems for Rural African American Emerging Adults

    Science.gov (United States)

    Brody, Gene H.; Yu, Tianyi; Chen, Yi-fu; Kogan, Steven M.; Smith, Karen

    2012-01-01

    Objective: This report addresses the long-term efficacy of the Adults in the Making (AIM) prevention program on deterring the escalation of alcohol use and development of substance use problems, particularly among rural African American emerging adults confronting high levels of contextual risk. Method: African American youths (M age, pretest =…

  13. Stability of Strength and Deformation Characteristics of Expanded Polystyrene (EPS within the Time of Long-Term Investigation of Creep Strain under Permanent Compressive Loading

    Directory of Open Access Journals (Sweden)

    Saulius VAITKUS

    2013-05-01

    Full Text Available The results of investigation of strength (s10 %, scr and deformability (E characteristics of expanded polystyrene specimens are presented. The results are based on the short-term compression in the organization of long-term creep study. For the experiments identical specimens stored 5 years at ambient temperature (23 ±2 °C and relative humidity (50 ±5 % as well specimens after removal long-term loading were used. There were established, that difference between experimental values of stress and initial modulus of tested expanded polystyrene specimens with confidence probability P = 90 % (on-sided test is negligible (random.DOI: http://dx.doi.org/10.5755/j01.ms.19.2.4442

  14. Poly-L-lysine-modified reduced graphene oxide stabilizes the copper nanoparticles with higher water-solubility and long-term additively antibacterial activity.

    Science.gov (United States)

    Ouyang, Yu; Cai, Xiang; Shi, QingShan; Liu, Lili; Wan, Dongliang; Tan, Shaozao; Ouyang, Yousheng

    2013-07-01

    In order to improve the water-solubility and long-term antibacterial activity of copper nanoparticles (CuNPs), a poly-L-lysine-modified reduced graphene oxide (PLL-rGO) was used as the carrier of CuNPs, and a poly-L-lysine/reduced graphene oxide/copper nanoparticles (PLL-rGO-CuNPs) hybrid was prepared by anchoring the CuNPs on the reduced graphene oxide surface. The novel PLL-rGO-CuNPs hybrid was characterized and the antibacterial activity of it on gram-negative Escherichia coli and Gram-positive Staphylococcus aureus was tested. Such a hybrid showed additively antibacterial activity, and the CuNPs on PLL-rGO were more stable than those on polyvinyl pyrrolidone, resulting in long-term additively antibacterial effect. Meanwhile, this hybrid showed excellent water-solubility, suggesting great potential application in microbial control.

  15. Significance Analysis of Building Long-term Mechanism of Social Stability in Ethnic Minority%构建少数民族地区社会稳定长效机制的战略意义

    Institute of Scientific and Technical Information of China (English)

    高翔

    2011-01-01

    构建少数民族地区社会稳定长效机制,是根据少数民族地区社会关系发展规律和维稳工作规律,探索维护少数民族地区社会稳定长期效应的工作机理及其制度体系的一项重要工作。对保持少数民族地区长治久安、民族团结、经济发展与社会和谐具有重要意义。%building a long-term mechanism of social stability in ethnic minority areas is an important work, and it has to explore the laws and long-term effects of social stability in accordance with social relations in the areas. Therefore, the research will be significant for maintaining long-term stability, national unity, economic development and social harmony in ethnic minority areas.

  16. Long term stability of rh-Cu/Zn-superoxide dismutase (SOD)-liposomes prepared by the cross-flow injection technique following International Conference on Harmonisation (ICH)-guidelines.

    Science.gov (United States)

    Vorauer-Uhl, Karola; Wagner, Andreas; Katinger, Hermann

    2002-07-01

    The current market position of liposomes as drug carriers is still being discussed with regard to large scale production, product characterisation and the stability of the dispersions. In this study, long term stability of liposomal suspensions with encapsulated rh-Cu/Zn-superoxide dismutase was tested according to the International Conference on Harmonisation (ICH) recommendations. The guidelines of the ICH provide general requirements for stability testing for registration and export in particular. The Institute of Applied Microbiology has examined a process to produce large amounts of pharmaceutical-grade liposomes for the treatment of inflammatory diseases by topical application. For the evaluation of its long-term storage stability, liposomal stability and protein stability were tested under appropriate conditions. Therefore, size alterations of the vesicles, protein release and protein activity were evaluated. During the observation period, neither significant alterations of the liposomes nor any protein degradation could be detected. In the light of these findings our liposomal formulations seem to provide chemical, physical and biological stability according to the definitions of the ICH. Appropriate lipid compounds and environmental factors, in combination with an optimised process and adequate storage conditions, facilitate the production of liposome dispersions suitable as drug carriers on the market.

  17. Sm0.5Sr0.5CoO3-δ-infiltrated cathodes for solid oxide fuel cells with improved oxygen reduction activity and stability

    Science.gov (United States)

    Wang, Fucun; Chen, Dengjie; Shao, Zongping

    2012-10-01

    Sm0.5Sr0.5CoO3-δ (SSC)-impregnated cathodes are fabricated by the solution infiltration of metal nitrates. The effects of complexing agents on the phase structure and the effects of pore formers on the porosity of the scaffold are examined and optimized. The thermal expansion behavior, electrical conductivities and electrochemical performance of the cathodes are characterized and optimized. A pure perovskite phase is formed after heating at 800 °C by adding a relatively small quantity of glycine as the complexing agent. Polyvinyl butyral is selected as the pore former for the preparation of porous Sm0.2Ce0.8O1.9 (SDC) scaffolds. The thermal expansion coefficient increases slightly from 12.74 × 10-6 K-1 to 13.28 × 10-6 K-1 after infiltrating 20 wt% SSC into the SDC scaffold. The infiltrated cathode with 20 wt% SSC + 80 wt% SDC shows the electrical conductivity of 15 S cm-1 at 700 °C. A well-connected SSC network is formed in the cathode after infiltrating 20 wt% SSC into the SDC scaffold. Cathode polarization resistance values as low as 0.05 Ω cm2, peak power density values as high as 936 mW cm-2 and stable performance throughout 325 h of operation at 700 °C suggest that the cathodes with the 20 wt% SSC-infiltrated SDC are suitable for practical application. However, for the SSC infiltrated into the 8 mol% yttria-stabilized zirconia scaffold, the interfacial reaction continues to occur during the stability test at 700 °C. SDC is preferred as a scaffold for the infiltration of SSC to ensure long-term operational stability.

  18. Long-term urethral catheterisation.

    Science.gov (United States)

    Turner, Bruce; Dickens, Nicola

    This article discusses long-term urethral catheterisation, focusing on the relevant anatomy and physiology, indications for the procedure, catheter selection and catheter care. It is important that nurses have a good working knowledge of long-term catheterisation as the need for this intervention will increase with the rise in chronic health conditions and the ageing population.

  19. Long-term performance and stability of a continuous granular airlift reactor treating a high-strength wastewater containing a mixture of aromatic compounds.

    Science.gov (United States)

    Ramos, Carlos; Suárez-Ojeda, María Eugenia; Carrera, Julián

    2016-02-13

    Continuous feeding operation of an airlift reactor and its inoculation with mature aerobic granules allowed the successful treatment of a mixture of aromatic compounds (p-nitrophenol, o-cresol and phenol). Complete biodegradation of p-nitrophenol, o-cresol, phenol and their metabolic intermediates was achieved at an organic loading rate of 0.61 g COD L(-1)d(-1). Stable granulation was obtained throughout the long-term operation (400 days) achieving an average granule size of 2.0 ± 1 mm and a sludge volumetric index of 26 ± 1 mL g(-1) TSS. The identified genera in the aerobic granular biomass were heterotrophic bacteria able to consume aromatic compounds. Therefore, the continuous feeding regimen and the exposure of aerobic granules to a mixture of aromatic compounds make possible to obtain good granulation and high removal efficiency.

  20. Long-Term IQ Stability Using the WISC-IV and WAIS-IV among a Sample of Special Education Students

    Science.gov (United States)

    Spector, Hayley

    2013-01-01

    The present study investigated the stability of scores on the WISC-IV and WAIS-IV over an approximate six-year period. Previous research using older versions of the WISC and WAIS have suggested that these scales demonstrate strong stability of scores. Since research that has compared the stability of scores between the WISC-IV and the WAIS-IV is…

  1. R&D of MCFC matrix for long term operation

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Takashi; Fujita, Yoji; Urushibata, Hiroaki; Sasaki, Akira [Mitsubishi Electric Corp., Hyogo (Japan)

    1996-12-31

    Long term operation is an essential subject in the commercialization of the Molten Carbonate Fuel Cell (MCFC). Material stability is important for the development of the MCFC. particularly for long term operation. In this paper, the specification and the stabilization of MCFC matrix arc investigated, with the aim of producing 40000 hours of operation. It is common knowledge that matrix thickness has a large influence on shorting time, as shorting is caused by the dissolution of the nickel oxide cathodes. Therefore, the optimum thickness of a matrix designed for 40000 hours operation without the nickel shorting was sought. The influences of different electrolytes and matrix specifications on the shorting time were measured with accelerated cell tests. The internal resistance of the matrix was also estimated. Gamma( {gamma} )-lithium aluminate (LiAlO{sub 2}) powder with a sub-micron particle diameter is commonly used for a raw material of matrix to retain molten carbonate electrolytes. This is because most researchers found that {gamma}-LiA1O{sub 2} was the most stable material in the MCFC environment among the three allotropic forms alpha ( {alpha} ), beta ( {beta} ), and {gamma}. However. two problems with the stability of {gamma} -LiAlO{sub 2} are being vigorously discussed. especially in Japan: particle growth causes decreasing electrolyte retention, and the transformation of {gamma} to {alpha}. This transformation contradicts the accepted opinion that {gamma} is the most stable form. In this paper, the particle growth and the phase transformation of LiAlO{sub 2} are examined with post-test analyses. The influence of matrix degradation on cell performance is also considered.

  2. 铂电阻温度计长期稳定性的试验研究%Study on the Long-term Stability Test for Platinum Resistance Thermometer

    Institute of Scientific and Technical Information of China (English)

    吴承汕

    2015-01-01

    基于铂电阻温度计作为国际温标量值传递的计量标准器具,其长期稳定性对计量性能的重要性,提出了考核长期稳定性的加速老化试验公式和试验方法.以标准铂电阻温度计为试验对象,与自然存放、实际使用情况下的考核方法一起对其长期稳定性进行了试验研究.结果表明,加速老化试验方法可用于铂电阻温度计和其他温度计的长期稳定性的考核试验.三种不同的试验方法所引起的Rtp变化差异较小,加速老化试验引起Wzn的变化最大,可达到10mK.%As measurement standard instruments of quantity value transfer for ITS-90, the long-term stability of platinum resistance thermometer (PRT) is very important.This paper presents accelerated aging test formula and test method.The long-term stability was studied on standard platinum resistance thermometer (SPRT) with using accelerated aging test, test methods of the natural storage and under the condition of the actual usage .The results show that, the accelerated aging test method can be used to test the long-term stability of PRT or other thermometer. TheRtp changes little between the three different test methods,but the change of WZn reached 10mK that caused by the accelerated aging test.

  3. Working Fluid Stability in Large-Scale Organic Rankine Cycle-Units Using Siloxanes—Long-Term Experiences and Fluid Recycling

    Directory of Open Access Journals (Sweden)

    Tobias G. Erhart

    2016-05-01

    Full Text Available The results in this work show the influence of long-term operation on the decomposition of working fluids in eight different organic rankine cycle (ORC power plants (both heat-led and electricity-led in a range of 900 kW el to 2 MW el . All case study plants are using octamethyltrisiloxane (MDM as a working fluid; the facilities are between six to 12 years old. Detailed analyses, including the fluid distribution throughout the cycle, are conducted on one system. All presented fluid samples are analyzed via head space gas chromatography mass spectrometry (HS-GC-MS. Besides the siloxane composition, the influence of contaminants, such as mineral oil-based lubricants (and their components, is examined. In most cases, the original working fluid degrades to fractions of siloxanes with a lower boiling point (low boilers and fractions with a higher boiling point (high boilers. As a consequence of the analyses, a new fluid recycling and management system was designed and tested in one case study plant (Case Study #8. Pre-post comparisons of fluid samples prove the effectiveness of the applied methods. The results show that the recovery of used working fluid offers an alternative to the purchase of fresh fluid, since operating costs can be significantly reduced. For large facilities, the prices for new fluid range from € 15 per liter (in 2006 to € 22 per liter (in 2013, which is a large reinvestment, especially in light of filling volumes of 4000 liters to 7000 liters per unit. Using the aforementioned method, a price of € 8 per liter of recovered MDM can be achieved.

  4. Electrodeposition, characterization and long term stability of NiW and NiWZn coatings on copper substrate in alkaline solution

    Science.gov (United States)

    Sürme, Yavuz; Gürten, A. Ali; Kayakırılmaz, Kadriye

    2013-07-01

    This paper describes the electrodeposition of Ni, NiW and NiWZn coatings onto copper surfaces from electrolyte solutions containing Na3C6H5O7, Na2WO4, NiSO4 and ZnSO4. The electrocatalytic effects of electrodeposited coatings were investigated for hydrogen evolution reactions in 1 M NaOH solution. Surface characterization studies were carried out by energy dispersive X-ray spectroscopy, scanning electron microscopy, atomic force microscopy and cross-section analysis. The effect of operating conditions on the chemical composition, microstructure and electrocatalytic properties of Ni-W coatings was studied. The Zn ions were used to improve the active surface area and catalytic activity of the electrodeposited surface. The electrocatalytic activity of NiW and NiWZn coated electrodes for the hydrogen evolution reaction in alkaline solution was compared with that of an electrodeposited Ni electrode and copper substrate by using cathodic polarization curves and electrochemical impedance spectroscopy techniques over 96 h of electrolysis. The results proved that the NiWZn coated electrode showed better electrocatalytic activity and durability than bare Cu, Ni and NiW coatings.

  5. 论少数民族地区社会稳定长效机制体系构建%On the Construction of Long-term Mechanism for the Social Stability of Ethnic Minority Areas

    Institute of Scientific and Technical Information of China (English)

    高翔

    2012-01-01

    The long-term mechanism for the social stability of ethnic minority areas is constituted by four mechanism systems: mechanism of stability promotion by national harmony, mechanism of stability promotion by development, mechanism of stability promotion by innovation of social management, and mechanism of sta- bility preservation by the rule of law. These mechanism systems are a series of comprehensive governancemechanisms that fundamentally addresses the main elements that affect the social stability ol the ethmc minori- ty areas, and important mechanisms that maintain the ethnic people's fundamental interests, ensure the long- term stability of ethnic areas and safeguard national security and border security. They can optimize the envi- ronmental function of economical and social development of ethnic areas for the long term and promote harmo- nious socialism construction of ethnic areas.%少数民族地区社会稳定长效机制体系由四个机制系统构成:一是以民族和谐促稳定机制,二是以发展促稳定机制,三是以社会管理创新促稳定机制,四是以法治保稳定机制。这一机制体系是从源头上、从根本上解决影响民族地区社会稳定的主要因素的综合治理机制,是维护民族地区人民群众根本利益和确保民族地区长治久安、维护国家安全以及边疆安全的重要机制,从而长期优化民族地区经济与社会发展环境功能、促进民族地区社会主义和谐社会建设。

  6. Genetic analyses of Per.C6 cell clones producing a therapeutic monoclonal antibody regarding productivity and long-term stability.

    Science.gov (United States)

    Tsuruta, Lilian Rumi; Lopes Dos Santos, Mariana; Yeda, Fernanda Perez; Okamoto, Oswaldo Keith; Moro, Ana Maria

    2016-12-01

    Genetic characterization of protein-producing clones represents additional value to cell line development. In the present study, ten Per.C6 clones producing a Rebmab100 monoclonal antibody were selected using two cloning methods: six clones originated from limiting dilution cloning and four by the automated colony picker ClonePix FL. A stability program was performed for 50 generations, including 4 batches distributed along the timeframe to determine specific productivity (Qp) maintenance. Four stable clones (two from limiting dilution and two from ClonePix FL) were further evaluated. The relative mRNA expression levels of both heavy chain (HC) and light chain (LC) genes were verified at generations 0, 30-35, and 50-55 of the stability program. At generations 0 and 30-35, LC gene expression level was higher than HC gene, whereas at generation 50-55, the opposite prevailed. A high correlation was observed between Qp and HC or LC mRNA expression level for all clones at each generation analyzed along the continuous culture. The mRNA stability study was performed at steady-state culture. The LC gene displayed a higher half-life and lower decay constant than HC gene, accounting for the higher observed expression level of LC mRNA in comparison to HC mRNA. Clone R6 was highlighted due its high Qp, mRNA expression levels, and mRNA stability. Besides the benefits of applying genetic characterization for the selection of stable and high-producing clones, the present study shows for the first time the correlation between Qp and HC or LC expression levels and also mRNA stability in clones derived from human cell line Per.C6(®).

  7. Excellent Long-Term Stability of Power Conversion Efficiency in Non-Fullerene-Based Polymer Solar Cells Bearing Tricyanovinylene-Functionalized n-Type Small Molecules.

    Science.gov (United States)

    Ko, Eun Yi; Park, Gi Eun; Lee, Ji Hyung; Kim, Hyung Jong; Lee, Dae Hee; Ahn, Hyungju; Uddin, Mohammad Afsar; Woo, Han Young; Cho, Min Ju; Choi, Dong Hoon

    2017-03-15

    New small molecules having modified acceptor strength and π-conjugation length and containing dicyanovinylene (DCV) and tricyanovinylene (TCV) as a strongly electron-accepting unit with indacenodithiophene, IDT(DCV)2, IDT(TCV)2, and IDTT(TCV)2, were synthesized and studied in terms of their applicability to polymer solar cells with PTB7-Th as an electron-donating polymer. Intriguingly, the blended films containing IDT(TCV)2 and IDTT(TCV)2 exhibited superior shelf life stabilities of more than 1000 h without any reduction in the initial power conversion efficiency. The low-lying lowest unoccupied molecular orbital energy levels and robust internal morphologies of small TCV-containing molecules could afford excellent shelf life stability.

  8. Site-Selective Controlled Dealloying Process of Gold-Silver Nanowire Array: a Simple Approach towards Long-Term Stability and Sensitivity Improvement of SERS Substrate

    Science.gov (United States)

    Wiriyakun, Natta; Pankhlueab, Karuna; Boonrungsiman, Suwimon; Laocharoensuk, Rawiwan

    2016-12-01

    Limitations of achieving highly sensitive and stable surface-enhanced Raman scattering (SERS) substrate greatly concern the suitable method for fabrication of large-area plasmonic nanostructures. Herein we report a simple approach using template-based synthesis to create a highly ordered two-dimensional array of gold-silver alloy nanowires, followed by the controlled dealloying process. This particular step of mild acid etching (15%v/v nitric acid for 5 min) allowed the formation of Raman hot spots on the nanowire tips while maintaining the integrity of highly active alloy composition and rigid nanowire array structure. Full consideration of SERS substrate performance was accomplished using 4-mercaptobenzoic acid (4-MBA) as a probe molecule. Exceedingly higher SERS signal (150-fold) can be achieved with respect to typical gold film substrate. Moreover, an excellent stability of SERS substrate was also determined for over 3 months storage time. In contrast to the previous studies which stability improvement was accomplished at a cost of sensitivity reduction, the simultaneous improvement of sensitivity and stability makes the controlled dealloying process an excellent choice of SERS substrate fabrication. In addition, uniformity and reproducibility studies indicated satisfactory results with the acceptable values of relative standard deviation.

  9. Paddy Soil Stability and Mechanical Properties as Affected by Long-Term Application of Chemical Fertilizer and Animal Manure in Subtropical China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Wet stability, penetration resistance (PR), and tensile strength (TS) of paddy soils under a fertilization experiment for 22 years were determined to elucidate the function of soil organic matter in paddy soil stabilization. The treatments included no fertilization (CK), normal chemical fertilization (NPK), double the NPK application rates (2NPK), and NPK mixed with organic manure (NPK+OM). Compared with CK, fertilization increased soil organic carbon (SOC) and soil porosity. The results of soil aggregate fragmentation degree (SAFD) showed that fast wetting by water was the key fragmentation mechanism. Among the treatments, the NPK+OM treatment had the largest size of water-stable aggregates and greatest normal mean weight diameter (NMWD) (P ≤ 0.05), but the lowest PR and TS in both cultivated horizon (Ap) and plow pan. The CK and 2NPK treatments were measured with PR > 2.0 MPa and friability index < 0.20,respectively, in the Ap horizon, suggesting that the soils was mechanically unfavourable to root growth and tillage. In the plow pan, the fertilization treatments had greater TS and PR than in CK. TS and PR of the tested soil aggregates were negatively correlated to SOC content and soil porosity. This study suggested that chemical fertilization could cause deterioration of mechanical properties while application of organic manure could improve soil stability and mechanical properties.

  10. Effect of Long-term Wearing Rigid Contact Lenses on the Stability of Tear Film%长期配戴硬性角膜接触镜对泪膜稳定性的影响

    Institute of Scientific and Technical Information of China (English)

    王俞方; 夏世刚; 罗洁; 陈磊; 燕建军

    2015-01-01

    Objective To investigate the effect of long-term wearing rigid contact lenses on the stability of tear film. Methods Eighty ( one hundred sixty eyes) patients were randomly divided into four groups:Group one,Long-term wearing RGP ( twenty patients,forty eyes);Group two,Long-term wearing orthokeratology lenses at night ( twenty-two patients,forty-four eyes);Group three,Long-term wearing soft contact lenses ( twenty patients,forty eyes); Normal control,low myopia patients without a history of wearing contact lenses (eighteen patients,thirty-six eyes). Patients’ vision,Schirmer I test, break-up time ( BUT) of tear film,conjunctival impression cytology ( CIC) ,and tear film fern experiments were performed before wearing lenses,wearing for one month,wearing for six month,wearing for one year,wearing for two years,respective-ly. Results The results of Schirmer I test and break-up time ( BUT) of tear film in each experimental group were re-duced as compared with normal control group. The difference was statistically significant (P<0. 05). After long-term wear-ing contact lenses,the conjunctival goblet cells was decreased in all experimental groups,and can not form a good ferning phenomenon. Conclusions Long-term wearing contact lenses can result in decreasing the stability of tear film and re-duce tear secretion.%目的:探讨长期配戴硬性角膜接触镜对泪膜稳定性的影响。方法选取80例(160眼)患者分成四组:硬性角膜接触镜( RGP组):长期配戴RGP (20例,40眼);角膜塑形镜组:长期夜间配戴角膜塑形镜(22例,44眼);软性接触镜组:长期配戴软性接触镜(20例,40眼);对照组:为无角膜接触镜配戴史的低度近视患者(18例,36眼),分别在戴镜前和戴镜后1个月、6个月、1年、2年检测视力,施墨(Schirmer I)试验检测泪腺分泌功能,泪膜破裂时间( BUT)测定泪膜破裂时间,结膜印迹细胞学( CIC)观察结膜表层细胞形态学改变及结膜杯状细胞数目,

  11. Long-term stability of human genomic and human papillomavirus DNA stored in BD SurePath and Hologic PreservCyt liquid-based cytology media.

    Science.gov (United States)

    Agreda, Patricia M; Beitman, Gerard H; Gutierrez, Erin C; Harris, James M; Koch, Kristopher R; LaViers, William D; Leitch, Sharon V; Maus, Courtney E; McMillian, Ray A; Nussbaumer, William A; Palmer, Marcus L R; Porter, Michael J; Richart, Gregory A; Schwab, Ryan J; Vaughan, Laurence M

    2013-08-01

    We evaluated the effect of storage at 2 to 8°C on the stability of human genomic and human papillomavirus (HPV) DNA stored in BD SurePath and Hologic PreservCyt liquid-based cytology media. DNA retained the ability to be extracted and PCR amplified for more than 2.5 years in both medium types. Prior inability to detect DNA in archived specimens may have been due to failure of the extraction method to isolate DNA from fixed cells.

  12. Characterization of the leaching behaviour of concrete mortars and of cement-stabilized wastes with different waste loading for long term environmental assessment.

    Science.gov (United States)

    van der Sloot, H A

    2002-01-01

    The leaching behaviour of cement-based products-both construction products and cement-stabilized wastes--have been shown to be similar after assessing the leaching characteristics by means of a pH dependence leaching test. This procedure is particularly suited to identifying the chemical speciation of materials. Geochemical modelling has shown a number of solubility controlling phases in this largely inorganic matrix, that can very well explain the observed leaching patterns as a function of pH. Understanding these relationships allows the prediction of leaching behaviour under other exposure conditions and to improve the ultimate quality of products, if so desired. The role of ettringite-type phases for the binding of oxyanions in the pH range above pH 12 has been identified before and confirmed in this work. The order of incorporation follows from the ratio between the maximum leachability at mildly alkaline pH and at high pH. Increased levels of sulfate negatively influence the binding of oxyanions in cement-stabilized waste through site competition.

  13. Long-term culture and cryopreservation does not affect the stability and functionality of human embryonic stem cell-derived hepatocyte-like cells.

    Science.gov (United States)

    Mandal, Arundhati; Raju, Sheena; Viswanathan, Chandra

    2016-02-01

    Human embryonic stem cells (hESCs) are predicted to be an unlimited source of hepatocytes which can pave the way for applications such as cell replacement therapies or as a model of human development or even to predict the hepatotoxicity of drug compounds. We have optimized a 23-d differentiation protocol to generate hepatocyte-like cells (HLCs) from hESCs, obtaining a relatively pure population which expresses the major hepatic markers and is functional and mature. The stability of the HLCs in terms of hepato-specific marker expression and functionality was found to be intact even after an extended period of in vitro culture and cryopreservation. The hESC-derived HLCs have shown the capability to display sensitivity and an alteration in the level of CYP enzyme upon drug induction. This illustrates the potential of such assays in predicting the hepatotoxicity of a drug compound leading to advancement of pharmacology.

  14. The long-term effects on aggregate stability (AS) from a forest fire of varying intensity in a Mediterranean environment (1994-2012).

    Science.gov (United States)

    Velasco, Antonio; Alcañiz, Meritxell; Úbeda, Xavier; Pereira, Paulo; Mataix-Solera, Jorge

    2013-04-01

    Forest fires can affect many soil properties and this fact is deeply connected with fire severity, intensity, soil type and many others factors. Aggregate stability (AS) indicates the soil structure resilience in response to external mechanical forces. AS is one of the factors that strongly affect on soil erodibility and infiltration. This property can be used as an indicator of the state of the soil structure and physical stability. The aim of this study is to analyze the soil AS of a determined area that suffered a wildfire in 1994 and compare them with a control area with the same characteristics. The study area is located in the Cadiretes Massif, in the northernmost zone of the Catalan Coastal Ranges, northeast Spain, at an altitude of around 190 - 250 m.a.m.s.l. The Cadiretes Massif is predominantly granite, although soils developed over Paleozoic metamorphic rocks such as schist and slates can also be found. In some areas metamorphic features underlie this relief. The massif is covered by dense Mediterranean vegetation, e.g. Quercus suber, Arbutus unedo, Erica arborea, and in some places Pinus pinaster plantations are found. This area receives about 700 - 800 mm of annual rainfall, with a fairly marked seasonal variability. The maximum is registered in autumn. Summer temperatures often surpass 25°C, while in winter temperatures are generally mild. The predominant soil type in Cadiretes is classified as a Lithic Xerept, with a 15 cm deep sandy-loam A horizon. In the control forest area, this horizon is protected by a 3 cm deep O horizon of moder humus. Three areas with different burnt intensity were identified in 1994 and they are the same plots that were chosen to sample in 2012. The 4 plots (Low intensity, Medium Intensity, High Intensity and Control) had the same orientation (S) and slope (5%). The TDI (Ten Drop Impact) test, that simulates rainfall impact on aggregates, was used to measure AS in the laboratory. Twenty samples were collected per plot. Ten

  15. Chemical stability of La2O3 in La2O3-Mo cathode materials

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Chemical stability of La2O3 in carbonized and uncarbonized La2O3-Mo cathodes was studied by in-situ XPS analysis. Experimental results show that chemical stability of La2O3 is not good enough. In vacuum and at high temperature, oxygen can be dissociated from the lattice of La2O3 in the uncarbonized La2O3-Mo cathode. Binding energy shifts of La?3d5/2 and La?3d3/2 core peaks, and obvious decrease of satellite peak intensity in La?3d doublet with increasing temperature show that metallic La appears at carbonized La2O3-Mo cathode surface at high temperature.

  16. 用自监测信息的卫星钟长稳特性评估软件设计%DESIGNING EVALUATION SOFTWARE FOR LONG-TERM STABILITY PERFORMANCE OF SATELLITE CLOCK USING AUTONOMOUS MONITORING INFORMATION

    Institute of Scientific and Technical Information of China (English)

    崔小准; 王璐; 毕少筠; 董海青

    2015-01-01

    利用卫星钟相位差的自监测信息进行在轨导航卫星星钟长稳性能估计的方法实现简单,能满足实际评估需要。由此开发了相应的软件。该软件读取地面接收机解调的卫星自监测信息,通过软件操作完成卫星钟各观察时段主备钟相位差计算,然后通过分析实现卫星钟长稳特性评估。软件具有卫星主备钟监测相位计满程刻度的修正功能和野值剔除功能,能修正由于各卫星钟实际频率与标称频率差异带来的相差计算误差,剔除小概率频率突变值,降低长稳特性评估的误差。软件界面友好,操作简单,在导航卫星在轨测试和在轨管理中得到应用。%The method of estimating long-term stability performance of on-board satellites clock using autonomous monitoring information of satellite’s phase difference for in-orbit navigation satellites is simple in implementation and can meet the requirement of actual assessment.Therefore the corresponding software has been developed.The software reads the self-monitoring information demodulated by ground receivers,completes the calculation of phase difference between master and slave clocks of satellite clock in each observation time period through software operation,and then realises the evaluation of long-term stability performance of satellite clock by analyses.The software has full scale correction function and outliers elimination function for phase meters of master and slave satellite clocks’monitoring, which can correct the calculation errors of phase differences brought about by the differences between actual frequency of each satellite clock and nominal frequency,and weed out mutated value of small probability frequency,as well as reduce the error of long-term stability performanceassessment.The software is friendly in interface,easy to operate,and has been applied in in-orbit testing and management of navigation satellites.

  17. Long-term stability of thermophilic co-digestion submerged anaerobic membrane reactor encountering high organic loading rate, persistent propionate and detectable hydrogen in biogas.

    Science.gov (United States)

    Qiao, Wei; Takayanagi, Kazuyuki; Niu, Qigui; Shofie, Mohammad; Li, Yu You

    2013-12-01

    The performance of thermophilic anaerobic co-digestion of coffee grounds and sludge using membrane reactor was investigated for 148 days, out of a total research duration of 263 days. The OLR was increased from 2.2 to 33.7 kg-COD/m(3)d and HRT was shortened from 70 to 7 days. A significant irreversible drop in pH confirmed the overload of reactor. Under a moderately high OLR of 23.6 kg-COD/m(3)d, and with HRT and influent total solids of 10 days and 150 g/L, respectively, the COD removal efficiency was 44.5%. Hydrogen in biogas was around 100-200 ppm, which resulted in the persistent propionate of 1.0-3.2g/L. The VFA consumed approximately 60% of the total alkalinity. NH4HCO3 was supplemented to maintain alkalinity. The stability of system relied on pH management under steady state. The 16SrDNA results showed that hydrogen-utilizing methanogens dominates the archaeal community. The propionate-oxidizing bacteria in bacterial community was insufficient.

  18. Phase behavior of fluorocarbon and hydrocarbon double-chain hydroxylated and galactosylated amphiphiles and bolaamphiphiles. Long-term shelf-stability of their liposomes.

    Science.gov (United States)

    Clary, L; Gadras, C; Greiner, J; Rolland, J P; Santaella, C; Vierling, P; Gulik, A

    1999-06-01

    This paper describes the morphological characterization, by freeze-fracture electron microscopy, and the thermotropic phase behavior, by differential scanning calorimetry and/or X-ray scattering, of aqueous dispersions of various hydroxylated and galactosylated double-chain amphiphiles and bolaamphiphiles, several of them containing one or two hydrophobic fluorocarbon chains. Colloidal systems are observed in water with the hydroxylated hydrocarbon or fluorocarbon bolaamphiphiles only when they are dispersed with a co-amphiphile such as rac-1,2-dimyristoylphosphatidylcholine (DMPC) or rac-1,2-distearoylphosphatidylcholine (DSPC). Liposomes are formed providing the relative content of bolaamphiphiles does not exceed 20% mol. Most of these liposomes can be thermally sterilized and stored at room temperature for several months without any significant modification of their size and size distribution. The hydrocarbon galactosylated bolaamphiphile HO[C24][C12]Gal forms in water a lamellar phase (the gel to liquid-crystal phase transition is complete at 45 degrees C) and a Im3m cubic phase above 47 degrees C. The fluorocarbon HO[C24][F6C5]Gal analog displays a more complex and metastable phase behavior. The fluorinated non-bolaform galactosylated [F8C7][C16]AEGal and SerGal amphiphiles form lamellar phases in water. Low amounts (10% molar ratio) of the HO[C24][F6C5]Gal or HO[C24][C12]Gal bolaamphiphiles or of the single-headed [F8C7][C16]AEGal improve substantially the shelf-stability of reference phospholipon/cholesterol 2/1 liposomes. These liposomes when co-formulated with a single-headed amphiphile from the SerGal series are by far less stable.

  19. In Situ Engineering of the Electrode-Electrolyte Interface for Stabilized Overlithiated Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Tyler [Department of Mechanical Engineering, University of Colorado at Boulder, Boulder CO 80309 USA; SiILion, Inc., Broomfield CO 80020 USA; Piper, Daniela Molina [SiILion, Inc., Broomfield CO 80020 USA; Sun, Huaxing [Department of Chemistry, University of Colorado at Boulder, Boulder CO 80309 USA; Porcelli, Timothy [Department of Chemistry, University of Colorado at Boulder, Boulder CO 80309 USA; Kim, Seul Cham [Department of Material Science and Engineering, Seoul National University, Seoul 151-742 South Korea; Han, Sang Sub [Department of Material Science and Engineering, Seoul National University, Seoul 151-742 South Korea; Choi, Yong Seok [Department of Material Science and Engineering, Seoul National University, Seoul 151-742 South Korea; Tian, Chixia [Energy Storage and Distributed Resources Division, Lawrence Berkeley National Laboratory, Berkeley CA 94720 USA; Nordlund, Dennis [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park CA 94025 USA; Doeff, Marca M. [Energy Storage and Distributed Resources Division, Lawrence Berkeley National Laboratory, Berkeley CA 94720 USA; Ban, Chunmei [Center of Chemical and Materials Science, National Renewable Energy Laboratory, Golden CO 80401 USA; Cho, Sung-Jin [Joint School of Nanoscience and Nanoengineering, North Carolina A& T State University, Greensboro NC 27411 USA; Oh, Kyu Hwan [Department of Material Science and Engineering, Seoul National University, Seoul 151-742 South Korea; Lee, Se-Hee [Department of Mechanical Engineering, University of Colorado at Boulder, Boulder CO 80309 USA

    2017-01-05

    The first-ever demonstration of stabilized Si/lithium-manganese-rich full cells, capable of retaining >90% energy over early cycling and >90% capacity over more than 750 cycles at the 1C rate (100% depth-of-discharge), is made through the utilization of a modified ionic liquid electrolyte capable of forming a favorable cathode-electrolyte interface.

  20. [{sup 131}I]Iodoazomycin arabinoside for low-dose-rate isotope radiotherapy: radiolabeling, stability, long-term whole-body clearance and radiation dosimetry estimates in mice

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Piyush [Department of Oncologic Imaging, Cross Cancer Institute, University of Alberta, Edmonton, Alberta, T6G 2N8 (Canada); McQuarrie, Steven A. [Department of Oncologic Imaging, Cross Cancer Institute, University of Alberta, Edmonton, Alberta, T6G 2N8 (Canada); Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, T6G 2N8 (Canada); Zhou, Aihya [Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, T6G 2N8 (Canada); McEwan, Alexander J.B. [Department of Oncologic Imaging, Cross Cancer Institute, University of Alberta, Edmonton, Alberta, T6G 2N8 (Canada); Wiebe, Leonard I. [Department of Oncologic Imaging, Cross Cancer Institute, University of Alberta, Edmonton, Alberta, T6G 2N8 (Canada) and Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, T6G 2N8 (Canada)]. E-mail: leonard.wiebe@ualberta.ca

    2005-08-01

    Background: The preliminary characterization of [{sup 131}I]iodoazomycin arabinoside ([{sup 131}I]IAZA) as a potential radiotherapeutic radiopharmaceutical is described. Methods: High-specific-activity [{sup 131}I]IAZA was prepared in therapeutic doses (up to 3 GBq per batch) by isotope exchange in pivalic acid melt and was purified on Sep-Pak cartridges. Stability in 15% ethanol in saline at 4 deg C was determined by high-performance liquid chromatography. IAZA cytotoxicity (IC{sub 50}, {approx}0.1 mM) against both murine (EMT-6) and human (143B, 143B-LTK) tumor cells determined by MTT test was in the range previously reported for EMT-6 cells using a clonogenic assay. Tissue radioactivity levels were measured in a murine tumor model for the 24- to 168-h postinjection period. Radiation dose estimates obtained from the tissue activity levels for this period were calculated from pharmacokinetic (WinNonlin) and dosimetry (MIRD and RAdiation Dose Assessment Resource) parameters. Results: The radioiodination efficiency was >90%, but with systematic losses during Sep-Pak purification, the recovered yields of [{sup 131}I]IAZA were {approx}75%. The product (specific activity, 4.6-6.4 GBq/{mu}mol) was stable for at least 2 weeks, with only {approx}6% degradation over this storage period. Extended biodistribution studies in Balb/c mice bearing implanted EMT-6 tumors showed that the highest tumor/blood radioactivity ratio (T/B; 4.8) occurred 24 h after dosing; the T/B ratio was {approx}1.5 at the end of the 7-day study. The 24- to 168-h tissue radioactivity data fit a one-compartment model except for liver data, which best fit a two-compartment model. Dosimetry estimates showed a tumor self-dose of 7.4 mGy/MBq, which is several-fold higher than for the liver or the kidney. Conclusions: [{sup 131}I]IAZA can be efficiently radiolabeled at high specific activity, purified by a simple Sep-Pak technique and stored with little radiolysis or chemical decomposition at these specific

  1. Sustainability of large-scale constructed stormwater treatment areas (STAs) in the Everglades basin: Long-term stability and phosphorus removal performance

    Science.gov (United States)

    Bhomia, R. K.; Reddy, R.

    2012-12-01

    Treatment wetlands are utilized globally to reduce the amount of nutrients discharged into downstream water bodies. Sustainability of these wetlands depend on accumulation of stable (non-reactive) forms of retained nutrients. Storage of such stable pools of nutrients is influenced by a range of environmental factors such as hydrology, temperature, vegetation and nutrient loading. Our focus was to characterize phosphorus (P) retained by treatment wetlands in the Everglades Agricultural Area Basin. Six stormwater treatment areas (STAs) covering approx. 18,000 ha area are currently operational in south Florida. To date STAs have removed over 1,400 mt of P. The importance of wetland vegetation in P removal is well documented, however limited information is available on the role of different vegetation types on stability of accreted P. Based on dominant vegetation species, existing cells of these STAs are designated and maintained as emergent aquatic vegetation (EAV) and submerged aquatic vegetation (SAV) cells. We characterized soil P into reactive and stable pools and compared these pools between SAV and EAV. By using operationally defined P fractionation scheme we determined inorganic, organic and residual P fractions, of which first two fractions constituted reactive forms, while residual P represented stable form. Intact soil cores were collected from 44 sites spanning STA-1W and STA-2. Soil cores were divided into 3 layers- floc, RAS and pre-STA soil. Floc and RAS accumulated after STA became operational, while underlying peat represented pre-STA soils. Across the sites, SAV and EAV cells did not differ significantly in relative proportion of reactive and stable P pools. Reactive P constituted 75% of TP in floc sections of EAV cells and 62% of TP in SAV cells. In RAS, the reactive P was 64% of TP for EAV and 67% of TP for SAV cells. However, floc and RAS sections of EAV cells showed higher organic P fractions (50% and 40% of TP) compared to SAV (23% and 37% of TP

  2. A single-mode external cavity diode laser using an intra-cavity atomic Faraday filter with short-term linewidth <400 kHz and long-term stability of <1 MHz

    Science.gov (United States)

    Keaveney, James; Hamlyn, William J.; Adams, Charles S.; Hughes, Ifan G.

    2016-09-01

    We report on the development of a diode laser system - the "Faraday laser" - using an atomic Faraday filter as the frequency-selective element. In contrast to typical external-cavity diode laser systems which offer tunable output frequency but require additional control systems in order to achieve a stable output frequency, our system only lases at a single frequency, set by the peak transmission frequency of the internal atomic Faraday filter. Our system has both short-term and long-term stability of less than 1 MHz, which is less than the natural linewidth of alkali-atomic D-lines, making similar systems suitable for use as a "turn-key" solution for laser-cooling experiments.

  3. A single-mode external cavity diode laser using an intra-cavity atomic Faraday filter with short-term linewidth $<400$ kHz and long-term stability of $<1$ MHz

    CERN Document Server

    Keaveney, James; Adams, Charles S; Hughes, Ifan G

    2016-01-01

    We report on the development of a diode laser system - the `Faraday laser' - using an atomic Faraday filter as the frequency-selective element. In contrast to typical external-cavity diode laser systems which offer tunable output frequency but require additional control systems in order to achieve a stable output frequency, our system only lases at a single frequency, set by the peak transmission frequency of the internal atomic Farady filter. Our system has both short-term and long-term stability of less than 1~MHz, which is less than the natural linewidth of alkali-atomic D-lines, making similar systems suitable for use as a `turn-key' solution for laser cooling experiments.

  4. A single-mode external cavity diode laser using an intra-cavity atomic Faraday filter with short-term linewidth <400 kHz and long-term stability of <1 MHz.

    Science.gov (United States)

    Keaveney, James; Hamlyn, William J; Adams, Charles S; Hughes, Ifan G

    2016-09-01

    We report on the development of a diode laser system - the "Faraday laser" - using an atomic Faraday filter as the frequency-selective element. In contrast to typical external-cavity diode laser systems which offer tunable output frequency but require additional control systems in order to achieve a stable output frequency, our system only lases at a single frequency, set by the peak transmission frequency of the internal atomic Faraday filter. Our system has both short-term and long-term stability of less than 1 MHz, which is less than the natural linewidth of alkali-atomic D-lines, making similar systems suitable for use as a "turn-key" solution for laser-cooling experiments.

  5. MIPAS IMK/IAA CFC-11 (CCl3F) and CFC-12 (CCl2F2) measurements: accuracy, precision and long-term stability

    Science.gov (United States)

    Eckert, E.; Laeng, A.; Lossow, S.; Kellmann, S.; Stiller, G.; von Clarmann, T.; Glatthor, N.; Höpfner, M.; Kiefer, M.; Oelhaf, H.; Orphal, J.; Funke, B.; Grabowski, U.; Haenel, F.; Linden, A.; Wetzel, G.; Woiwode, W.; Bernath, P. F.; Boone, C.; Dutton, G. S.; Elkins, J. W.; Engel, A.; Gille, J. C.; Kolonjari, F.; Sugita, T.; Toon, G. C.; Walker, K. A.

    2016-07-01

    the comparison of HATS and MIPAS measurements taken at 3 km below the tropopause mainly stay within 10-50 pptv (corresponding to ˜ 2-10 % for CFC-12) for the RR and the FR period. Between ˜ 15 and 30 km, most comparisons agree within 10-20 pptv (10-20 %), apart from ILAS-II, which shows large differences above ˜ 17 km. Overall, relative differences are usually smaller for CFC-12 than for CFC-11. For both species - CFC-11 and CFC-12 - we find that differences at the lower end of the profile tend to be larger at higher latitudes than in tropical and subtropical regions. In addition, MIPAS profiles have a maximum in their mixing ratio around the tropopause, which is most obvious in tropical mean profiles. Comparisons of the standard deviation in a quiescent atmosphere (polar summer) show that only the CFC-12 FR error budget can fully explain the observed variability, while for the other products (CFC-11 FR and RR and CFC-12 RR) only two-thirds to three-quarters can be explained. Investigations regarding the temporal stability show very small negative drifts in MIPAS CFC-11 measurements. These instrument drifts vary between ˜ 1 and 3 % decade-1. For CFC-12, the drifts are also negative and close to zero up to ˜ 30 km. Above that altitude, larger drifts of up to ˜ 50 % decade-1 appear which are negative up to ˜ 35 km and positive, but of a similar magnitude, above.

  6. Novel cathodes for low-temperature solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, M.; Xia, C. [Georgia Inst. of Tech., Atlanta, GA (United States). Center for Innovative Fuel Cell and Battery Technologies

    2002-04-04

    A solid-oxide fuel cell that operates at 500 C (instead of 600 C and higher), with lower material cost and better long-term stability, is presented. Its key piece is a cathode made of a silver/copper-doped bismuth vanadate (Ag-BI-CUVOX) composite, which reduces oxygen at lower temperatures and diminishes the resistance between the cathode and the electrolyte. (orig.)

  7. Experimental Researches on Long-Term Strength of Granite Gneiss

    Directory of Open Access Journals (Sweden)

    Lin Liu

    2015-01-01

    Full Text Available It is important to confirm the long-term strength of rock materials for the purpose of evaluating the long-term stability of rock engineering. In this study, a series of triaxial creep tests were conducted on granite gneiss under different pore pressures. Based on the test data, we proposed two new quantitative methods, tangent method and intersection method, to confirm the long-term strength of rock. Meanwhile, the isochronous stress-strain curve method was adopted to make sure of the accuracy and operability of the two new methods. It is concluded that the new methods are suitable for the study of the long-term strength of rock. The effect of pore pressure on the long-term strength of rock in triaxial creep tests is also discussed.

  8. Long-Term Dynamics of Autonomous Fractional Differential Equations

    Science.gov (United States)

    Liu, Tao; Xu, Wei; Xu, Yong; Han, Qun

    This paper aims to investigate long-term dynamic behaviors of autonomous fractional differential equations with effective numerical method. The long-term dynamic behaviors predict where systems are heading after long-term evolution. We make some modification and transplant cell mapping methods to autonomous fractional differential equations. The mapping time duration of cell mapping is enlarged to deal with the long memory effect. Three illustrative examples, i.e. fractional Lotka-Volterra equation, fractional van der Pol oscillator and fractional Duffing equation, are studied with our revised generalized cell mapping method. We obtain long-term dynamics, such as attractors, basins of attraction, and saddles. Compared with some existing stability and numerical results, the validity of our method is verified. Furthermore, we find that the fractional order has its effect on the long-term dynamics of autonomous fractional differential equations.

  9. Long-term stability of salivary cortisol

    DEFF Research Database (Denmark)

    Garde, A H; Hansen, Åse Marie

    2005-01-01

    The measurement of salivary cortisol provides a simple, non-invasive, and stress-free measure frequently used in studies of the hypothalamic-pituitary-adrenal axis activity. In research projects, samples are often required to be stored for longer periods of time either because of the protocol of ...

  10. Long-term stability of arch support and bedrock of Daning River Bridge%大宁河特大拱桥拱座-基岩长期稳定性研究

    Institute of Scientific and Technical Information of China (English)

    杨建平; 陈卫忠; 于洪丹; 谭贤君

    2011-01-01

    The arch support at Wushan end of Daning River Bridge is constructed on weathered solution-collapse breccias,which is soft and prone to creep.Evaluation of long-term stability of arch support and breccias is of great importance for the security of service of Daning River Bridge.Based on the laboratory creep test results of weathered solution-collapse breccias,a creep constitutive model is established and the parameters are proposed.Using the creep model,the long-term evolution of stress and deformation of the arch support and breccias is analyzed by means of the 3D finite element method(FEM).The openings and shear stress between the contact surface of arch support and breccias are studied.Numerical results show that:(1) the creep of breccias can cause local tensile stress concentration on thrust resistance piles;(2) the arch support and bedrock show compatible deformation during long-term creep,and the opening of the contact surface is very small.In addition,the shear stress in most part of the contact surface is less than 0.1 MPa.This study may be helpful for the design of arch support and long-term maintenance of the slope.%大宁河特大拱桥巫山端拱座建造在弱风化溶崩角砾岩基岩上,拱座–基岩的长期稳定性是桥梁安全运营的关键。依据弱风化溶崩角砾岩蠕变试验得到的幂函数形式蠕变方程,建立了三维拱座–基岩接触面有限元模型,通过数值仿真研究了桥梁长期运营过程中弱风化溶崩角砾岩基岩的应力特征、变形特征、拱座的应力分布变化规律、拱座–基岩接触面剪切应力分布及张开度变化等特性,研究成果表明:①基岩长期蠕变导致应力调整,拱座抗推桩会出现拉应力集中;②长期蠕变过程中拱座–基岩协调变形,接触面张开度很小,拱座–基岩接触面上顺桥向剪切应力也较小。研究成

  11. 西南某水电站坝肩抗力体长期稳定性分析%NUMERICAL LONG-TERM STABILITY OF DAM ABUTMENT RESISTANCE BODY FOR A HYDROPOWER STATION IN SOUTHWEST CHINA

    Institute of Scientific and Technical Information of China (English)

    杨根兰; 黄润秋

    2011-01-01

    Long-term stability of dam abutment resistance body is very important for a hydropower station. The a-butment resistance body stability of complex rock mass dam under the action of water thrust is particularly important. There are widely altered rocks in the dam abutment of a hydropower station in Southwest China. On the basis of altered rock rheological property and its viscous-elastic-plastic constitutive model, the stress and deformation fields characteristics in the resistance body slope have been simulated with 3D numerical method during the reservoir operation period. The study results show that te third stress field is formed after 6months of water storage. The dam abutment resistance body is in the most dangerous situation. Local destruction between altered rock and fault may appear. According to the simulated deformation value and plastic zones after 5 years of water storage,the abutment resistance body of the whole dam is in a long-term stable state.%水电工程对坝肩抗力体长期稳定性要求极高,因此,对于复杂岩土体坝肩抗力体在水推力作用下的稳定性评价显得尤为重要.西南某水电工程坝肩岩体普遍发育有蚀变岩,因此需对其抗力体长期稳定性进行评价.根据考虑蚀变岩体流变特性的黏-弹-塑性本构模型,对水库蓄水运行期抗力体边坡应力、形变场等特征进行了三维数值模拟研究.研究表明,坝肩抗力体在蓄水6个月后“三次应力场”基本形成,即此时抗力体处于最危险状态,可能会出现蚀变岩带与断层交叉部位的局部破坏;通过对蓄水5a后模拟得到的变形值及塑性区变化情况分析,得出坝肩抗力体整体上是长期稳定的.

  12. 商业银行负债稳定性与长期流动性管理%The Stability of Commercial Bank Deposits and Long-term Liquidity Management

    Institute of Scientific and Technical Information of China (English)

    苗晓宇

    2013-01-01

    稳定(核心)存款是存款总额中长期稳定的部分,具有成本低、利率敏感性低且稳定性高的特点。稳定存款的测算对于商业银行的流动性管理具有重要的意义。本文使用HP滤波法估算出商业银行的稳定存款,通过借鉴国际先进银行普遍采用的流动性缺口模型法,计算了各期的流动性缺口并将其应用到样本银行的长期流动性管理工作。结果表明该方法操作简便易于计算,测量结果与银行实际经营情况相符,对现阶段我国商业银行流动性管理实践具有较强的指导意义。%Stable deposits is the long-term stability part of total deposits, it has the characteristics of low cost, low interest rate sensitivity and high stability. Estimating stable deposits has the important significance of liquidity management for the commercial banks. In this paper, we used the HP filter method to estimate banks' stable deposits, and we used the liquidity gap method which was generally adopted by many international advanced banks, X bank as an example, to estimate the liq-uidity gap in each stage .In the end, we did an empirical research on the application of stable deposits on long-term liquidity management. The results show that the method is simple and the result is consistent with banks' actual operation situation, which has strong practical significance to the management of liquidity at the present stage of China's commercial banks.

  13. Effects of enhancing soil organic carbon sequestration in the topsoil by fertilization on crop productivity and stability: Evidence from long-term experiments with wheat-maize cropping systems in China.

    Science.gov (United States)

    Zhang, Xubo; Sun, Nan; Wu, Lianhai; Xu, Minggang; Bingham, Ian J; Li, Zhongfang

    2016-08-15

    Although organic carbon sequestration in agricultural soils has been recommended as a 'win-win strategy' for mitigating climate change and ensuring food security, great uncertainty still remains in identifying the relationships between soil organic carbon (SOC) sequestration and crop productivity. Using data from 17 long-term experiments in China we determined the effects of fertilization strategies on SOC stocks at 0-20cm depth in the North, North East, North West and South. The impacts of changes in topsoil SOC stocks on the yield and yield stability of winter wheat (Triticum aestivum L.) and maize (Zea mays L.) were determined. Results showed that application of inorganic fertilizers (NPK) plus animal manure over 20-30years significantly increased SOC stocks to 20-cm depth by 32-87% whilst NPK plus wheat/maize straw application increased it by 26-38% compared to controls. The efficiency of SOC sequestration differed between regions with 7.4-13.1% of annual C input into the topsoil being retained as SOC over the study periods. In the northern regions, application of manure had little additional effect on yield compared to NPK over a wide range of topsoil SOC stocks (18->50MgCha(-1)). In the South, average yield from manure applied treatments was 2.5 times greater than that from NPK treatments. Moreover, the yield with NPK plus manure increased until SOC stocks (20-cm depth) increased to ~35MgCha(-1). In the northern regions, yield stability was not increased by application of NPK plus manure compared to NPK, whereas in the South there was a significant improvement. We conclude that manure application and straw incorporation could potentially lead to SOC sequestration in topsoil in China, but beneficial effects of this increase in SOC stocks to 20-cm depth on crop yield and yield stability may only be achieved in the South.

  14. Asthma Medicines: Long-Term Control

    Science.gov (United States)

    ... Size Email Print Share Asthma Medicines: Long-term Control Page Content Article Body Corticosteroids Synthetic versions of ... form, they are used exclusively for long-term control; they are not very effective for acute symptoms. ...

  15. Long term testing of PSI-membranes

    Energy Technology Data Exchange (ETDEWEB)

    Huslage, J.; Brack, H.P.; Geiger, F.; Buechi, F.N.; Tsukada, A.; Scherer, G.G. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Long term tests of PSI membranes based on radiation-grafted FEP and ETFE films were carried out and FEP-based membranes were evaluated by monitoring the in-situ membrane area resistance measured by a current pulse method. By modifying our irradiation procedure and using the double crosslinking concept we obtain reproducible membrane cell lifetimes (in term of in-situ membrane resistance) of greater than 5000 hours at 60-65{sup o}C. Preliminary tests at 80-85{sup o}C with lifetimes of greater than 2500 demonstrate the potential long term stability of PSI proton exchange membranes based on FEP over the whole operating temperature range of low-temperature polymer electrolyte fuel cells. Radiation grafted PSI membranes based on ETFE have better mechanical properties than those of the FEP membranes. Mechanical properties are particularly important in large area cells and fuel cell stacks. ETFE membranes have been tested successfully for approximately 1000 h in a 2-cell stack (100 cm{sup 2} active area each cell). (author) 4 figs., 4 refs.

  16. Gratitude in Long Term Care

    Directory of Open Access Journals (Sweden)

    Brooke Abrams Sunding

    2015-04-01

    Full Text Available An exploratory study was conducted to examine the effectiveness of a group gratitude intervention with 29 permanent residents at a long term care/skilled nursing facility in improving elder mood, behavior and well- being over a 3 week time period. The sample included individuals diagnosed with dementia, other cognitive impairment, major depressive disorder, insomnia and generalized anxiety disorder. The gratitude intervention consisted of asking elders to share what they are thankful for at the dinner table each day. Measures included the Elder Well Being Scale and The Dinner Rating Scale. On both measures, higher scores indicated better functioning. To test the hypothesis that post treatment elder well-being will be significantly higher than pretreatment elder well-being ratings, a one-way ANOVA was conducted. Post-hoc tests revealed a statistically significant increase in Elder Well Being Scale scores. An ANOVA of comparing Dinner Ratings demonstrated a nonsignificant increase over the 3 week experiment. Implications are discussed.

  17. THE EFFECT OF A-SITE STOICHIOMETRY ON LSCF CATHODE PERFORMANCE AND STABILITY

    Energy Technology Data Exchange (ETDEWEB)

    Templeton, Jared W.; Hardy, John S.; Lu, Zigui; Stevenson, Jeffry W.

    2011-11-01

    Anode-supported solid oxide fuel cells (SOFCs) were prepared and tested identically except for variations in the A-site stoichiometry of the LSCF cathode. A commercial supplier provided lanthanum strontium cobalt ferrite (LSCF) powders that were stoichiometric [La0.6Sr0.4Co0.2Fe0.8O3-δ], A-site deficient [(La0.6Sr0.4)1-xCo0.2Fe0.8O3-δ], and Sr-deficient [La0.6Sr0.4-xCo0.2Fe0.8O3-δ], in which the imposed deficiency (x) was 0.02, 0.05, and 0.1 in the non-stoichiometric cases. Multiple 1,000 hour tests were run using each LSCF cathode composition. The performance and stability of the cells will be discussed.

  18. Stability of long term facilitation and expression of zif268 and Arc in the spinal cord dorsal horn is modulated by conditioning stimulation within the physiological frequency range of primary afferent fibers.

    Science.gov (United States)

    Haugan, F; Wibrand, K; Fiskå, A; Bramham, C R; Tjølsen, A

    2008-07-17

    Long term facilitation (LTF) of C-fiber-evoked firing of wide dynamic range neurons in the spinal dorsal horn in response to conditioning stimulation (CS) of afferent fibers is a widely studied cellular model of spinal nociceptive sensitization. Although 100 Hz CS of primary afferent fibers is commonly used to induce spinal cord LTF, this frequency exceeds the physiological firing range. Here, we examined the effects of electrical stimulation of the sciatic nerve within the physiological frequency range on the magnitude and stability of the C-fiber-evoked responses of wide dynamic range neurons and the expression of immediate early genes (c-fos, zif268, and Arc) in anesthetized rats. Stimulation frequencies of 3, 30 and 100 Hz all induced facilitation of similar magnitude as recorded at 1 h post-CS. Strikingly, however, 3 Hz-induced potentiation of the C-fiber responses was decremental, whereas both 30 and 100 Hz stimulation resulted in stable, non-decremental facilitation over 3 h of recording. The number of dorsal horn neurons expressing c-fos, but not zif268 or Arc, was significantly elevated after 3 Hz CS and increased proportionally with stimulation rate. In contrast, a stable LTF of C-fiber responses was obtained at 30 and 100 Hz CS, and at these frequencies there was a sharp increase in zif268 expression and appearance of Arc-positive neurons. The results show that response facilitation can be induced by stimulation frequencies in the physiological range (3 and 30 Hz). Three hertz stimulation induced the early phase of LTF, but the responses were decremental. Arc and zif268, two genes previously coupled to LTP of synaptic transmission in the adult brain, are upregulated at the same frequencies that give stable LTF (30 and 100 Hz). This frequency-dependence is important for understanding how the afferent firing pattern affects neuronal plasticity and nociception in the spinal dorsal horn.

  19. 长期培养的黄瓜毛状根中外源基因遗传稳定性分析%Genetic Stability Analysis of Exogenous Gene in Long-term Cultured Cucumber Hairy Roots

    Institute of Scientific and Technical Information of China (English)

    曹庆丰; 向太和; 孟莎莎; 王沙沙; 陆文怡

    2012-01-01

    In this study, it was investigated that the genetic stability ofgfp gene in the cucumber hairy roots that had been cultured on solid medium for 3 years. The analysis of PCR for gfp and rol (root loci) genes, qRT-PCR for gfp gene and Western blot for GFP protein were conducted, while green fluorescence was checked on hairy roots. The results showed that the expression of gfp driven by constitutive promoter 35S was relatively stable at both mRNA and protein levels. Furthermore, the morphology-related rol genes of the hairy roots after 3-year culturing can be amplified. Overall, this study provided important experimental supports for using hairy roots in the long-term industrial production of proteins and active ingredients of medicinal plants.%对在固体培养基上培养3年的黄瓜转gfp基因毛状根进行gfp和rol位点系列基因的PCR扩增、gfp的荧光定量PCR、Westernblot杂交以及荧光观察分析。结果显示,由组成型启动子35S驱动的g章在转录水平上能正常表达,而且能够翻译出编码蛋白;此外,培养3年后的毛状根,能扩增出与毛状根形态构成有关的rol系列基因。本研究结果表明长期培养的毛状根能保持其遗传稳定性,这为利用毛状根长期工厂化生产外源基因表达的蛋白产物和药用植物的活性成分提供了理论依据。

  20. Enhanced cycling stability of lithium sulfur batteries using sulfur-polyaniline-graphene nanoribbon composite cathodes.

    Science.gov (United States)

    Li, Lei; Ruan, Gedeng; Peng, Zhiwei; Yang, Yang; Fei, Huilong; Raji, Abdul-Rahman O; Samuel, Errol L G; Tour, James M

    2014-09-10

    A hierarchical nanocomposite material of graphene nanoribbons combined with polyaniline and sulfur using an inexpensive, simple method has been developed. The resulting composite, characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron microscopy, and X-ray diffraction analysis, has a good rate performance and excellent cycling stability. The synergistic combination of electrically conductive graphene nanoribbons, polyaniline, and sulfur produces a composite with high performance. The method developed here is practical for the large-scale development of cathode materials for lithium sulfur batteries.

  1. Stabilization of a cold cathode electron beam glow discharge for surface treatment

    Energy Technology Data Exchange (ETDEWEB)

    Mingolo, N.; Gonzalez, C.R. [Lab. de Haces Dirigidos, Depto. de Fisica, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, 1063 Buenos Aires (Argentina); Martinez, O.E. [Lab. de Electronica Cuantica, Depto. de Fisica, Universidad de Buenos Aires, Pabellon 1, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Rocca, J.J. [Department of Electrical Engineering, Colorado State University, Fort Collins, Colorado 80523 (United States)

    1997-10-01

    We have demonstrated that the reproducibility of electron beam pulses generated by a high power, cold cathode glow discharge is greatly improved by adding a small continuous keep-alive discharge current. A current of the order of 200 {mu}A was found to limit the shot to shot current variation to within 1.5{percent}. This stabilization in turn reduces by an order of magnitude the fluctuations of the energy density deposited on the target, demonstrating a reliable energy source for surface treatment. {copyright} {ital 1997 American Institute of Physics.}

  2. HOME LONG-TERM CARE IN POLAND

    Directory of Open Access Journals (Sweden)

    Ewa Kułagowska

    2011-06-01

    Full Text Available The considerable proportion of the elderly, the chronically ill and the disabled in community is an economic and organizational challenge for the state social policy. It requires a large, steadily increasing financing from the public funds and creating an optional care model to fulfill the needs of citizens and guarantee high quality services. Development of the long-term care is one of the problems to be solved. This paper presents: – a long-term care forms, organization and tasks; – a role of long-term care but particularly home longterm care to protect health in Poland; – problems related with home long-term care functioning.

  3. Thermionic Electron Emission Stability of Mo-La2O3 Cathode

    Institute of Scientific and Technical Information of China (English)

    周文元; 张久兴; 刘燕琴; 万小峰; 周美玲; 左铁镛

    2004-01-01

    The carbonizing process and its influence on the thermionic electron emission properties of Mo-La2O3 cathode materials were investigated. The carbonized temperature, carbonized time and the pressure of C6H6 are key factors of the carbonizing process. The carbonized ratio of Mo-La2O3 cathode increases with the increase of carbonizing temperature at low temperature. The highest carbonized ratio is 19.7% obtained at 1723 K, then the carbonized ratio decreases rapidly if temperature increases further. The carbonized ratio increases with the prolongation of carbonizing time during the process of first 6 min., after that the carbonization ratio changes little with the time increase, and the carbonized ratio increases with the increase of the C6H6 pressure when the pressure is low, the maximum carbonized ratio reaches 19.7% at 1.5×10-2 Pa, then the carbonized ratio goes down sharply when the C6H6 pressure is over 1.5×10-2 Pa. The emission properties at different operated temperatures and the emission current stability of FU-6051 tubes equipped with Mo-La2O3 cathodes were also studied in the article. The study results indicate that the emission can keep stable only when the operating temperature is from 1700 to 1800 K and the carbonized layer must be composed by Mo2C only. The FU-6051 tubes equipped with Mo-La2O3 cathodes have excellent stable emission current and the lifetime exceeds 3000 h when the cathode′s carbonized ratio is 19.7% operated at 1773 K.

  4. Preliminary Results of Field Emission Cathode Tests

    Science.gov (United States)

    Sovey, James S.; Kovaleski, Scott D.

    2001-01-01

    Preliminary screening tests of field emission cathodes such as chemical vapor deposited (CVD) diamond, textured pyrolytic graphite, and textured copper were conducted at background pressures typical of electric thruster test facilities to assess cathode performance and stability. Very low power electric thrusters which provide tens to hundreds micronewtons of thrust may need field emission neutralizers that have a capability of tens to hundreds of microamperes. From current voltage characteristics, it was found that the CVD diamond and textured metals cathodes clearly satisfied the Fowler-Nordheim emission relation. The CVD diamond and a textured copper cathode had average current densities of 270 and 380 mA/sq cm, respectively, at the beginning-of-life. After a few hours of operation the cathode emission currents degraded by 40 to 75% at background pressures in the 10(exp -5) Pa to 10(exp -4) Pa range. The textured pyrolytic graphite had a modest current density at beginning-of-life of 84 mA/sq cm, but this cathode was the most stable of all. Extended testing of the most promising cathodes is warranted to determine if current degradation is a burn-in effect or whether it is a long-term degradation process. Preliminary experiments with ferroelectric emission cathodes, which are ceramics with spontaneous electric polarization, were conducted. Peak current densities of 30 to 120 mA/sq cm were obtained for pulse durations of about 500 ns in the 10(exp -4) Pa pressure range.

  5. Thermodynamic stability of perovskite and lanthanum nickelate-type cathode materials for solid oxide fuel cells

    Science.gov (United States)

    Cetin, Deniz

    The need for cleaner and more efficient alternative energy sources is becoming urgent as concerns mount about climate change wrought by greenhouse gas emissions. Solid oxide fuel cells (SOFCs) are one of the most efficient options if the goal is to reduce emissions while still operating on fossil energy resources. One of the foremost problems in SOFCs that causes efficiency loss is the polarization resistance associated with the oxygen reduction reaction(ORR) at the cathodes. Hence, improving the cathode design will greatly enhance the overall performance of SOFCs. Lanthanum nickelate, La2NiO4+delta (LNO), is a mixed ionic and electronic conductor that has competitive surface oxygen exchange and transport properties and excellent electrical conductivity compared to perovskite-type oxides. This makes it an excellent candidate for solid oxide fuel cell (SOFC) applications. It has been previously shown that composites of LNO with Sm0.2Ce0.8O2-delta (SDC20) as cathode materials lead to higher performance than standalone LNO. However, in contact with lanthanide-doped ceria, LNO decomposes resulting in free NiO and ceria with higher lanthanide dopant concentration. In this study, the aforementioned instability of LNO has been addressed by compositional tailoring of LNO: lanthanide doped ceria (LnxCe 1-xO2,LnDC)composite. By increasing the lanthanide dopant concentration in the ceria phase close to its solubility limit, the LNO phase has been stabilized in the LNO:LnDC composites. Electrical conductivity of the composites as a function of LNO volume fraction and temperature has been measured, and analyzed using a resistive network model which allows the identification of a percolation threshold for the LNO phase. The thermomechanical compatibility of these composites has been investigated with SOFC systems through measurement of the coefficients of thermal expansion. LNO:LDC40 composites containing LNO lower than 50 vol%and higher than 40 vol% were identified as being

  6. Long-term survival after perforated diverticulitis

    NARCIS (Netherlands)

    J. Vermeulen (Jan); M.P. Gosselink (Martijn Pieter); W.C.J. Hop (Wim); E. van der Harst (Erwin); B.E. Hansen (Bettina); G.H.H. Mannaerts (Guido); P-P. Coene (Peter Paul); W.F. Weidema (Wibo); J.F. Lange (Johan)

    2011-01-01

    textabstractAim: Short-term survival after emergency surgery for perforated diverticulitis is poor. Less is known about long-term survival. The aims of this study were to evaluate long-term survival after discharge from hospital and to identify factors associated with prognosis. Method: All patients

  7. Virtual Models of Long-Term Care

    Science.gov (United States)

    Phenice, Lillian A.; Griffore, Robert J.

    2012-01-01

    Nursing homes, assisted living facilities and home-care organizations, use web sites to describe their services to potential consumers. This virtual ethnographic study developed models representing how potential consumers may understand this information using data from web sites of 69 long-term-care providers. The content of long-term-care web…

  8. Long term results of mandibular distraction

    Directory of Open Access Journals (Sweden)

    Batra Puneet

    2006-03-01

    Full Text Available Mandibular distraction osteogenesis has become a popular surgical modality due to its many advantages over conventional orthognathic surgical procedures. However, in spite of the technique having been used for over 15 years, no concrete long term results are available regarding the stability of results. We discuss the various studies which have reported either in favour or against the stablility of results after distraction. We report a series of 6 cases (3 unilateral and 3 bilateral distraction where distraction was carried out before puberty and followed them up to seven years after removal of distractors. This case series shows that results achieved by distraction osteogenesis are unstable or best unpredictable with respect to producing a permanent size increase in the mandible. The role of the distraction osteogenesis in overcoming the pterygomassetric sling is questionable. We suggest a multicenter study with adequate patient numbers treated with a similar protocol and documented after growth cessation to have meaningful conclusions on the debate of distraction osteogenesis versus orthognathic surgery.

  9. Long-Term Soft Denture Lining Materials

    Directory of Open Access Journals (Sweden)

    Grzegorz Chladek

    2014-08-01

    Full Text Available Long-term soft denture lining (LTSDL materials are used to alleviate the trauma associated with wearing complete dentures. Despite their established clinical efficacy, the use of LTSDLs has been limited due to the unfavorable effects of the oral environment on some of their mechanical and performance characteristics. The unresolved issue of LTSDL colonization by Candida albicans is particularly problematic. Silicone-based LTSDL (SLTSDL materials, which are characterized by more stable hardness, sorption and solubility than acrylic-based LTSDLs (ALTSDLs, are currently the most commonly used LTSDLs. However, SLTSDLs are more prone to debonding from the denture base. Moreover, due to their limitations, the available methods for determining bond strength do not fully reflect the actual stability of these materials under clinical conditions. SLTSDL materials exhibit favorable viscoelastic properties compared with ALTSDLs. Furthermore, all of the lining materials exhibit an aging solution-specific tendency toward discoloration, and the available cleansers are not fully effective and can alter the mechanical properties of LTSDLs. Future studies are needed to improve the microbiological resistance of LTSDLs, as well as some of their performance characteristics.

  10. Tunable frequency-stabilization of UV laser using a Hallow-Cathode Lamp of atomic thallium

    CERN Document Server

    Chen, Tzu-Ling; Shy, Jow-Tsong; Liu, Yi-Wei

    2013-01-01

    A frequency-stabilized ultraviolet laser system, locked to the thallium resonant transition of 377.5 nm, was demonstrated using a novel bichromatic spectroscopy technique for tuning the zero-crossing laser-lock point. The atomic thallium system is a promising candidate in atomic parity violation and permanent electric dipole moment experiments, and its 377.5 nm 6P1/2->7S1/2 transition is important for thallium laser cooling and trapping experiment. The pressure shift, owing to the high pressure bu?er gas of the hollow-cathode lamp, was observed using an atomic beam resonance as reference. Such a shift was corrected by adjusting the peak ratio of the two Doppler-free saturation pro?les resulted from two pumping beams with a 130 MHz frequency di?erence. The resulted frequency stability of the ultraviolet laser is ?0.5 MHz at 0.1 sec integration time. This scheme is compact and versatile for stabilizing UV laser systems, which acquire a sub-MHz stability and frequency tunability.

  11. Long-term outcome of meniscectomy

    DEFF Research Database (Denmark)

    Roos, Ewa M.; Ostenberg, A; Roos, H;

    2001-01-01

    To describe the long-term influence of meniscectomy on pain, functional limitations, and muscular performance. To assess the effects of radiographic osteoarthritis (OA), gender and age on these outcomes in patients with meniscectomy....

  12. Long Term Care Minimum Data Set (MDS)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Long-Term Care Minimum Data Set (MDS) is a standardized, primary screening and assessment tool of health status that forms the foundation of the comprehensive...

  13. Long-Term Care Ombudsman Program

    Science.gov (United States)

    ... Strategic Plan Federal Initiatives Career Opportunities Contact Us Administration on Aging (AoA) Long-Term Care Ombudsman Program ( ... Prevention HIV/AIDS Nutrition Services Oral Health Elder Justice & Adult Protective Services Elder Justice Coordinating Council Prevention ...

  14. Long-Term Ownership by Industrial Foundations

    DEFF Research Database (Denmark)

    Børsting, Christa Winther; Kuhn, Johan Moritz; Poulsen, Thomas

    2016-01-01

    Short-termism has become a serious concern for businesses and policy makers and this has inspired a search for governance arrangement to promote long term decision making. In this paper we study a particularly long-term ownership structure, which is fairly common in Northern Europe, particularly...... in Denmark. Industrial foundations are independent legal entities without owners or members typically with the dual objective of preserving the company and using excess profits for charity. We use a unique Danish data set to examine the governance of foundation-owned companies. We show that they are long-term...... in several respects. Foundations hold on to their shares for longer. Foundation-owned companies replace managers less frequently. They have more conservative capital structures with less leverage. Their companies survive longer. Their business decisions appear to be more long term. This paper supports...

  15. Pituitary diseases : long-term clinical consequences

    NARCIS (Netherlands)

    Klaauw, Agatha Apolonia van der

    2008-01-01

    This thesis describes various studies during the long-term follow-up of patients after treatment for pituitary diseases. The focus of this thesis is acromegaly, growth hormone deficiency, sleep and quality of life. Various aspects are described.

  16. Strategies to curb structural changes of lithium/transition metal oxide cathode materials & the changes’ effects on thermal & cycling stability

    Science.gov (United States)

    Xiqian, Yu; Enyuan, Hu; Seongmin, Bak; Yong-Ning, Zhou; Xiao-Qing, Yang

    2016-01-01

    Structural transformation behaviors of several typical oxide cathode materials during a heating process are reviewed in detail to provide in-depth understanding of the key factors governing the thermal stability of these materials. We also discuss applying the information about heat induced structural evolution in the study of electrochemically induced structural changes. All these discussions are expected to provide valuable insights for designing oxide cathode materials with significantly improved structural stability for safe, long-life lithium ion batteries, as the safety of lithium-ion batteries is a critical issue; it is widely accepted that the thermal instability of the cathodes is one of the most critical factors in thermal runaway and related safety problems. Project supported by the U.S. Department of Energy, the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies (Grant No. DE-SC0012704).

  17. Anticipating Long-Term Stock Market Volatility

    OpenAIRE

    Conrad, Christian; Loch, Karin

    2012-01-01

    We investigate the relationship between long-term U.S. stock market risks and the macroeconomic environment using a two component GARCH-MIDAS model. Our results provide strong evidence in favor of counter-cyclical behavior of long-term stock market volatility. Among the various macro variables in our dataset the term spread, housing starts, corporate profits and the unemployment rate have the highest predictive ability for stock market volatility . While the term spread and housing starts are...

  18. Long-term outcomes after severe shock.

    Science.gov (United States)

    Pratt, Cristina M; Hirshberg, Eliotte L; Jones, Jason P; Kuttler, Kathryn G; Lanspa, Michael J; Wilson, Emily L; Hopkins, Ramona O; Brown, Samuel M

    2015-02-01

    Severe shock is a life-threatening condition with very high short-term mortality. Whether the long-term outcomes among survivors of severe shock are similar to long-term outcomes of other critical illness survivors is unknown. We therefore sought to assess long-term survival and functional outcomes among 90-day survivors of severe shock and determine whether clinical predictors were associated with outcomes. Seventy-six patients who were alive 90 days after severe shock (received ≥1 μg/kg per minute of norepinephrine equivalent) were eligible for the study. We measured 3-year survival and long-term functional outcomes using the Medical Outcomes Study 36-Item Short-Form Health Survey, the EuroQOL 5-D-3L, the Hospital Anxiety and Depression Scale, the Impact of Event Scale-Revised, and an employment instrument. We also assessed the relationship between in-hospital predictors and long-term outcomes. The mean long-term survival was 5.1 years; 82% (62 of 76) of patients survived, of whom 49 were eligible for follow-up. Patients who died were older than patients who survived. Thirty-six patients completed a telephone interview a mean of 5 years after hospital admission. The patients' Physical Functioning scores were below U.S. population norms (P shock had a high 3-year survival rate. Patients' long-term physical and psychological outcomes were similar to those reported for cohorts of less severely ill intensive care unit survivors. Anxiety and depression were relatively common, but only a few patients had symptoms of posttraumatic stress disorder. This study supports the observation that acute illness severity does not determine long-term outcomes. Even extremely critically ill patients have similar outcomes to general intensive care unit survivor populations.

  19. Effect of Long-Term Different Fertilization on Maize Yield Stability in the Northeast Black Soil Region%长期不同施肥对东北黑土区玉米产量稳定性的影响

    Institute of Scientific and Technical Information of China (English)

    高洪军; 彭畅; 张秀芝; 李强; 朱平

    2015-01-01

    [Objective]This research was conducted to reveal the stability difference and dynamic of maize yield in the Northeast Black Soil region of China, and to provide scientific references for establishing the optimal fertilization pattern and promoting the sustainable production of maize.[Method]Based on the long-term experiment on Black Soil fertility and fertilizer efficiency in Gongzhuling city of Jilin province, the respond of maize yield and soil nutrient to eight fertilization patterns were analyzed: non-fertilization (CK), application of single chemical NP (NP), application of single chemical NK (NK), application of single chemical PK (PK), application of single chemical NPK (NPK), mixed application of low amounts of chemical fertilizer and manure (M1NPK), chemical fertilizer plus maize straw (SNPK), and mixed application of high amount chemical fertilizer and manure M2NPK).[Result]It was discovered that maize yield in chemical fertilizer plus organic manure treatments showed a significant increasing trend. There were no significant differences in average yields among the M1NPK, SNPK, and NPK treatments, in which the same N amounts were applied. The NPK treatment had a higher maize yield than the M1NPKand SNPK treatments in the first eleven years, but the result was the opposite in the recent fourteen years. Maize average yields of chemical fertilizer treatments showed an order of NPK>NP>NK>PK and CK during a 25 year period. The yield effects of chemical fertilizers N, P, and K were 33.0, 16.2, and 5.3 kg·kg-1 respectively. The application of organic fertilizer and chemical fertilizer had a higher sustainable yield index (SYI) from 0.712 to 0.798, but theSYI was very low in imbalance fertilization and no fertilizer treatments. The coefficient variation (CV) of maize yield was greater in the CK, PK, or NK treatments, which ranged from 18.5% to 34.7%, while the organic and inorganic fertilizer treatments had a lower CV of between 10.8%-13.0%. The average

  20. Investigating the stability of cathode materials for rechargeable lithium ion batteries

    Science.gov (United States)

    Huang, Yiqing

    Lithium ion batteries are widely used in portable electronic devices and electric vehicles. However, safety is one of the most important issues for the Li-ion batteries' use. Some cathode materials, such as LiCoO 2, are thermally unstable in the charged state. Upon decomposition these cathode materials release O2, which could react with organic electrolyte, leading to a thermal runaway. Thus understanding the stability of the cathode materials is critical to the safety of lithium ion batteries. Olivine-type LiMnPO4 is a promising cathode material for lithium ion batteries because of its high energy density. We have revealed the critical role of carbon in the stability and thermal behaviour of olivine MnPO 4 obtained by chemical delithiation of LiMnPO4. (Li)MnPO 4 samples with various particle sizes and carbon contents were studied. Carbon-free LiMnPO4 obtained by solid state synthesis in O 2 becomes amorphous upon delithiation. Small amounts of carbon (0.3 wt.%) help to stabilize the olivine structure, so that completely delithiated crystalline olivine MnPO4 can be obtained. Larger amount of carbon (2 wt.%) prevents full delithiation. Heating in air, O2, or N 2 results in structural disorder (< 300 °C), formation of an intermediate sarcopside Mn3(PO4)2 phase (350 -- 450 °C), and complete decomposition to Mn2P2O 7 on extended heating at 400 °C. Carbon protects MnPO4 from reacting with environmental water, which is detrimental to its structural stability. We not only studied the crystalline olivine MnPO4, but also investigated the amorphous products obtained from carbon-free LiMnPO 4. We have revealed the Mn dissolution phenomenon during chemical delithiation of LiMnPO4, which causes the amorphization of olivine MnPO 4. Properties of crystalline-MnPO4 obtained from carbon-coated LiMnPO4 and of amorphous product resulting from the delithiation of pure LiMnPO4 were studied and compared. The P-rich amorphous phases in the latter are considered to be MnHP2O7 and MnH2P

  1. Long-term follow-up study and long-term care of childhood cancer survivors

    Directory of Open Access Journals (Sweden)

    Hyeon Jin Park

    2010-04-01

    Full Text Available The number of long-term survivors is increasing in the western countries due to remarkable improvements in the treatment of childhood cancer. The long-term complications of childhood cancer survivors in these countries were brought to light by the childhood cancer survivor studies. In Korea, the 5-year survival rate of childhood cancer patients is approaching 70%; therefore, it is extremely important to undertake similar long-term follow-up studies and comprehensive long-term care for our population. On the basis of the experiences of childhood cancer survivorship care of the western countries and the current Korean status of childhood cancer survivors, long-term follow-up study and long-term care systems need to be established in Korea in the near future. This system might contribute to the improvement of the quality of life of childhood cancer survivors through effective intervention strategies.

  2. Long-term Multiwavelength Observations of Polars

    Science.gov (United States)

    Santana, Joshua; Mason, Paul A.

    2016-06-01

    Polars are cataclysmic variables with the highest magnetic field strengths (10-250 MG). Matter is accreted after being funneled by the strong magnetic field of the white dwarf. We perform a meta-study of multi-wavelength data of polars. Many polars have been observed in surveys, such as SDSS, 2MASS, ROSAT, just to name a few. Some polars have now been detected by the JVLA, part of an expanding class of radio CVs. A large subset of polars have long-term optical light curves from CRTS and AAVSO. We suggest that the long term light curves of polars display a variety of signature behaviors and may be grouped accordingly. Additional characteristics such a binary period, magnetic field strengths, X-ray properties, and distance estimates are examined in context with long-term observations.

  3. Thermal Stability and Reactivity of Cathode Materials for Li-Ion Batteries.

    Science.gov (United States)

    Huang, Yiqing; Lin, Yuh-Chieh; Jenkins, David M; Chernova, Natasha A; Chung, Youngmin; Radhakrishnan, Balachandran; Chu, Iek-Heng; Fang, Jin; Wang, Qi; Omenya, Fredrick; Ong, Shyue Ping; Whittingham, M Stanley

    2016-03-23

    The thermal stability of electrochemically delithiated Li0.1Ni0.8Co0.15Al0.05O2 (NCA), FePO4 (FP), Mn0.8Fe0.2PO4 (MFP), hydrothermally synthesized VOPO4, LiVOPO4, and electrochemically lithiated Li2VOPO4 is investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis, coupled with mass spectrometry (TGA-MS). The thermal stability of the delithiated materials is found to be in the order of NCA thermal run-away phenomenon in batteries at elevated temperature and so is inherently safer. The lithiated materials LiVOPO4, Li2VOPO4, and LiNi0.8Co0.15Al0.05O2 are found to be stable in the presence of electrolyte, but sealed-capsule high-pressure experiments show a phase transformation of VOPO4 → HVOPO4 → H2VOPO4 when VOPO4 reacts with electrolyte (1 M LiPF6 in EC/DMC = 1:1) between 200 and 300 °C. Using first-principles calculations, we confirm that the charged VOPO4 cathode is indeed predicted to be marginally less stable than FP but significantly more stable than NCA in the absence of electrolyte. An analysis of the reaction equilibria between VOPO4 and EC using a multicomponent phase diagram approach yields products and reaction enthalpies that are highly consistent with the experiment results.

  4. Keratoprosthesis: a long-term review.

    Science.gov (United States)

    Barnham, J J; Roper-Hall, M J

    1983-07-01

    A keratoprosthesis (KP), is an artificial cornea which is inserted into an opacified cornea in an attempt to restore useful vision or, less commonly, to make the eye comfortable in painful keratopathy. Results o a retrospective study of 35 patients, with 55 KP insertions, are reviewed with regard to visual acuity, length of time vision is maintained, retention time, and complication. Overall there were a number of long-term real successes, eith retention of the KP and maintenance of improved vision in eyes not amenable to conventional treatment. Careful long-term follow-up was needed, with further surgical procedures often being necessary.

  5. [Fetal pain: immediate and long term consequences].

    Science.gov (United States)

    Houfflin Debarge, Véronique; Dutriez, Isabelle; Pusniak, Benoit; Delarue, Eléonore; Storme, Laurent

    2010-06-01

    Several situations are potentially painful for fetuses, such as malformations and invasive procedures. Nociceptive pathways are known to be functional at 26 weeks. Even if it is not possible to evaluate the fetal experience of pain, it is essential to examine its immediate and long-term consequences. As early as the beginning of the second trimester, hemodynamic and hormonal responses are observed following fetal nociceptive stimulation, In experimental studies, long-term changes have been noted in the corticotrop axis, subsequent responses to pain, and behavior after perinatal nociceptive stimulation.

  6. Long-term home care scheduling

    DEFF Research Database (Denmark)

    Gamst, Mette; Jensen, Thomas Sejr

    In several countries, home care is provided for certain citizens living at home. The long-term home care scheduling problem is to generate work plans spanning several days such that a high quality of service is maintained and the overall cost is kept as low as possible. A solution to the problem...... provides detailed information on visits and visit times for each employee on each of the covered days. We propose a branch-and-price algorithm for the long-term home care scheduling problem. The pricing problem generates one-day plans for an employee, and the master problem merges the plans with respect...

  7. Pressurized air cathodes for enhanced stability and power generation by microbial fuel cells

    Science.gov (United States)

    He, Weihua; Yang, Wulin; Tian, Yushi; Zhu, Xiuping; Liu, Jia; Feng, Yujie; Logan, Bruce E.

    2016-11-01

    Large differences between the water and air pressure in microbial fuel cells (MFCs) can deform and damage cathodes. To avoid deformation, the cathode air pressure was controlled to balance pressure differences between the air and water. Raising the air pressures from 0 to 10 kPa at a set cathode potential of -0.3 V (versus Ag/AgCl) enhanced cathode performance by 17%, but pressures ≥25 kPa decreased current and resulted in air leakage into the solution. Matching the air pressure with the water pressure avoided cathode deformation and improved performance. The maximum power density increased by 15%, from 1070 ± 20 to 1230 ± 70 mW m-2, with balanced air and water pressures of 10-25 kPa. Oxygen partial pressures ≥12.5 kPa in the cathode compartment maintained the oxygen reduction rate to be within 92 ± 1% of that in ambient air. The use of pressurized air flow through the cathode compartments can enable closer spacing of the cathodes compared to passive gas transfer systems, which could make the reactor design more compact. The energy cost of pressurizing the cathodes was estimated to be smaller than the increase in power that resulted from the use of pressurized cathodes.

  8. 长期施肥下水稻土有机碳固持形态与特征%Characteristics of Organic Carbon Stabilization in Paddy Soil Under Long-term Different Fertilization

    Institute of Scientific and Technical Information of China (English)

    徐香茹; 蔡岸冬; 徐明岗; 汪景宽; 张文菊

    2015-01-01

    Understanding the mechanisms of soil organic carbon(SOC)stabilization would help improve soil carbon sequestration in paddy soil. In this paper, we obtained paddy soils from a 30 year experimental field under five different fertilization, including no fertilizer(con-trol), mineral nitrogen(N)-phosphorus(P)-potassium(K)fertilizers(NPK), 70%mineral N+30%organic N plus PK(NPKM7/3), 50%mineral N+50%organic N plus PK(NPKM5/5), and 30%mineral N+70%organic N plus PK(NPKM3/7). Organic N was provided from green manure and pig manure. The soils were subjected to separating unprotected, and physically, chemically, bio-chemically, physical-chemically, and physical-biochemically protected SOC fractions by a physical-chemical combined fractionation method. Except the unpro-tected light fraction and the occluded silt and clay-sized fraction, the mass proportion of all other SOC factions was significantly different be-tween the treatments. Compared with non-fertilization(CK)treatment, chemical fertilizers mixed with organic manure(NPKM7/3、NPKM5/5 and NPKM3/7)significantly increased the content of total SOC(19.1~25.0 g·kg-1), unprotected coarse particulate organic carbon(cPOM) (8.41~12.7 g·kg-1), and physically protected aggregate(μagg)organic carbon(6.41~6.62 g·kg-1)in red paddy soil(P﹤0.05). There were no significant differences for the chemically, biochemically, physical-chemically and physical-biochemically protected fractions between the five treatments. These results indicated that the unprotected cPOM and the physically protected μagg fractions were the most sensitive ones in long-term fertilization. There was a linear positive correlation between total SOC and tcPOM, physically protected μagg, and oc-cluded POM inside theμagg(iPOM)fraction(P﹤0.05), and their response efficiency to total SOC accumulation(the slope of the regression) was 0.5, 0.12, and 0.12 respectively. However, the response efficiency of non-hydrolysis clay and physic-chemically protected silt

  9. Microstructure and long-term creep properties of 9–12% Cr steels

    DEFF Research Database (Denmark)

    Hald, John

    2008-01-01

    Advanced microstructure characterisation and microstructure modelling has demonstrated that long-term microstructure stability in 9–12% Cr steels under technical loading conditions is equivalent to precipitate stability. Mo and W can have a positive influence on long-term creep strength of 9–12% Cr...... steels by Laves phase precipitation hardening. Unexpected breakdown of long-term creep stability of a number of alloys is caused by precipitation of the complex Z-phase nitride, which may completely dissolve fine V and Nb containing MX nitrides. High Cr contents of 10% and above in the steels accelerate...

  10. Stability of Conductive Carbon Additives for High-voltage Li-ion Battery Cathodes

    OpenAIRE

    Nilssen, Benedicte Eikeland

    2014-01-01

    Conductive carbon additives are important constituents of the current state-of-the-art Li-ion battery cathodes, as the traditional active cathode materials are characterized by too low electronic conductivities. In high-voltage Li-ion batteries, these additives are subject for anion intercalation and electrolyte oxidation, which might cause changes in the conductive carbon network in the cathode, and hence the overall cycling performance of the electrode. This thesis has focused on study the ...

  11. The long term characteristics of greenschist

    Science.gov (United States)

    Jang, Bo-An

    2016-04-01

    The greenschist in the Jinping II Hydropower Station in southwest China exhibits continuous creep behaviour because of the geological conditions in the region. This phenomenon illustrates the time-dependent deformation and progressive damage that occurs after excavation. In this study, the responses of greenschist to stress over time were determined in a series of laboratory tests on samples collected from the access tunnel walls at the construction site. The results showed that the greenschist presented time-dependent behaviour under long-term loading. The samples generally experienced two stages: transient creep and steady creep, but no accelerating creep. The periods of transient creep and steady creep increased with increasing stress levels. The long-term strength of the greenschist was identified based on the variation of creep strain and creep rate. The ratio of long-term strength to conventional strength was around 80% and did not vary much with confining pressures. A quantitative method for predicting the failure period of greenschist, based on analysis of the stress-strain curve, is presented and implemented. At a confining pressure of 40 MPa, greenschist was predicted to fail in 5000 days under a stress of 290 MPa and to fail in 85 days under the stress of 320 MPa, indicating that the long-term strength identified by the creep rate and creep strain is a reliable estimate.

  12. Long Term Transfer Effect of Metaphoric Allusion.

    Science.gov (United States)

    Hayes, David A.; Mateja, John A.

    A study was conducted to investigate the long term transfer effect of metaphoric allusion used to clarify unfamiliar subject matter. Forty-nine high school students were given unfamiliar prose materials variously augmented by metaphoric allusion. The subjects' immediate performance on a transfer task was compared to their performance on an…

  13. Consequences of long-term hyperparathyroidism

    NARCIS (Netherlands)

    Graal, M B; Wolffenbuttel, B H

    1998-01-01

    We describe a young woman with long-term untreated hyperparathyroidism with a superimposed vitamin D deficiency and an extremely decreased bone mineral density that was complicated by a vertebral fracture. Despite pretreatment with intravenous pamidronate and short-term vitamin D supplementation, se

  14. Cathodic micro-arc electrodeposition of yttrium stabilized zirconia (YSZ) coatings on FeCrAl alloy

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The formation of ceramic coatings on metal substrate by cathodic electrolytic deposition (CELD) has received more attention in recent years. But only thin films can be prepared via CELD. Yttrium stabilized zirconia (YSZ) ceramic coatings were deposited on FeCrAl alloy by a novel technique--cathodic micro-arc electrodeposition (CMED). The result shows that, when a high pulse electric field is applied to the cathode which was pre-deposited with a thin YSZ film, dielectric breakdown occurs and micro-arc discharges appear. Coatings with reasonably thickness of ~300μm and crystalline structure can be deposited on the cathode by utilizing the energy of the micro-arc. The thickness of the as-deposited coating is dominated by the voltage and the frequency. Y2O3 is co-deposited with ZrO2 when Y(NO3)3 was added to the electrolyte, which stabilize t-phase, t′- phase and c-phase of ZrO2 at room temperature. The amount of the m-ZrO2 in the coating is diminished by increasing the concentration of Y(NO3)3 in the electrolyte. This report describes the processing of CMED and studies the microstructure of the deposited YSZ coatings.

  15. Enhanced Oxygen and Hydroxide Transport in a Cathode Interface by Efficient Antibacterial Property of a Silver Nanoparticle-Modified, Activated Carbon Cathode in Microbial Fuel Cells.

    Science.gov (United States)

    Li, Da; Qu, Youpeng; Liu, Jia; Liu, Guohong; Zhang, Jie; Feng, Yujie

    2016-08-17

    A biofilm growing on an air cathode is responsible for the decreased performance of microbial fuel cells (MFCs). For the undesired biofilm to be minimized, silver nanoparticles were synthesized on activated carbon as the cathodic catalyst (Ag/AC) in MFCs. Ag/AC enhanced maximum power density by 14.6% compared to that of a bare activated carbon cathode (AC) due to the additional silver catalysis. After operating MFCs over five months, protein content on the Ag/AC cathode was only 38.3% of that on the AC cathode, which resulted in a higher oxygen concentration diffusing through the Ag/AC cathode. In addition, a lower pH increment (0.2 units) was obtained near the Ag/AC catalyst surface after biofouling compared to 0.8 units of the AC cathode, indicating that less biofilm on the Ag/AC cathode had a minor resistance on hydroxide transported from the catalyst layer interfaces to the bulk solution. Therefore, less decrements of the Ag/AC activity and MFC performance were obtained. This result indicated that accelerated transport of oxygen and hydroxide, benefitting from the antibacterial property of the cathode, could efficiently maintain higher cathode stability during long-term operation.

  16. Strategies for Stabilizing Nitrogenous Compounds in ECLSS Wastewater: Top-Down System Design and Unit Operation Selection with Focus on Bio-Regenerative Processes for Short and Long Term Scenarios

    Science.gov (United States)

    Lunn, Griffin M.

    2011-01-01

    Water recycling and eventual nutrient recovery is crucial for surviving in or past low earth orbit. New approaches and syste.m architecture considerations need to be addressed to meet current and future system requirements. This paper proposes a flexible system architecture that breaks down pretreatment , steps into discrete areas where multiple unit operations can be considered. An overview focusing on the urea and ammonia conversion steps allows an analysis on each process's strengths and weaknesses and synergy with upstream and downstream processing. Process technologies to be covered include chemical pretreatment, biological urea hydrolysis, chemical urea hydrolysis, combined nitrification-denitrification, nitrate nitrification, anammox denitrification, and regenerative ammonia absorption through struvite formation. Biological processes are considered mainly for their ability to both maximize water recovery and to produce nutrients for future plant systems. Unit operations can be considered for traditional equivalent system mass requirements in the near term or what they can provide downstream in the form of usable chemicals or nutrients for the long term closed-loop ecological control and life support system. Optimally this would allow a system to meet the former but to support the latter without major modification.

  17. A technique for long term continent gastrostomy.

    Science.gov (United States)

    Locker, D L; Foster, J E; Craun, M L; Torma, M J

    1985-01-01

    The use of the continent gastrostomy described herein offers several advantages: 1, the elimination of an indwelling catheter; 2, prevention of soiling at skin level; 3, long term access to the normal gastrointestinal track for alimentation without fear of tube erosion; 4, little compromise to gastric volume, and 5, ease of stoma care. We recommend this operation in instances when long term tube feedings are indicated either because of damage to the central nervous system or as a palliative treatment for patients with higher obstructing gastrointestinal malignant disease. The procedure may also be useful for patients in whom esophagogastric continuity has been interrupted (surgically or traumatically) and in whom reconstruction of the gastrointestinal tract would not seem feasible within a three to six month interval.

  18. Case presentation: long-term treatment.

    Science.gov (United States)

    Glucksman, Myron L

    2013-01-01

    The long-term (14 years) psychodynamic psychotherapy and pharmacotherapy of a depressed, suicidal, self-mutilating female patient is described. Her diagnoses included Chronic Posttraumatic Stress Disorder, Borderline Personality Disorder, and Recurrent Major Depression. Treatment was punctuated with repeated hospitalizations for self-mutilation (cutting) and suicidal ideation. A major determinant for her psychopathology was sexual abuse by her father from ages 6 to 14. This resulted in feelings of guilt and rage that she repressed and acted out through self-mutilating and suicidal behavior. A prolonged negative transference gradually became ambivalent, then positive. This was associated with her internalization of the healing qualities of the therapeutic relationship. She also gained insight into the reasons for her need to punish herself. Her initial self-representation as unworthy and bad was transformed into perceiving herself as a worthwhile, loving person. This case illustrates the role of long-term treatment for a complex, life-threatening, psychiatric disorder.

  19. Aligned Li(+) Tunnels in Core-Shell Li(NixMnyCoz)O2@LiFePO4 Enhances Its High Voltage Cycling Stability as Li-ion Battery Cathode.

    Science.gov (United States)

    Wu, Zhongzhen; Ji, Shunping; Liu, Tongchao; Duan, Yandong; Xiao, Shu; Lin, Yuan; Xu, Kang; Pan, Feng

    2016-10-12

    Layered transition-metal oxides (Li[NixMnyCoz]O2, NMC, or NMCxyz) due to their poor stability when cycled at a high operating voltage (>4.5 V) have limited their practical applications in industry. Earlier researches have identified Mn(II)-dissolution and some parasitic reactions between NMC surface and electrolyte, especially when NMC is charged to a high potential, as primarily factors responsible for the fading. In our previous work, we have achieved a capacity of NMC active material close to theoretical value and optimized its cycling performance by a depolarized carbon nanotubes (CNTs) network and an unique "pre-lithiation process" that generates an in situ organic coating (∼40 nm) to prevent Mn(II) dissolution and minimize the parasitic reactions. Unfortunately, this organic coating is not durable enough during a long-term cycling when the cathode operates at a high potential (>4.5 V). This work attempts to improve the surface protection of the NMC532 particles by applying an active inorganic coating consisting of nanosized- and crystal-orientated LiFePO4 (LFP) (about 50 nm, exposed (010) face) to generate a core-shell nanostructure of Li(NixMnyCoz)O2@LiFePO4. Transmission electron microscopy (TEM) and etching X-ray photoelectron spectroscopy have confirmed an intimate contact coating (about 50 nm) between the original structure of NMC and LFP single-particle with atomic interdiffusion at the core-shell interface, and an array of interconnected aligned Li(+) tunnels are observed at the interface by cross-sectional high-resolution TEM, which were formed by ball-milling and then strictly controlling the temperature below 100 °C. Batteries based on this modified NMC cathode material show a high reversible capacity when cycled between 3.0 and 4.6 V during a long-term cycling.

  20. Cutaneous oxalosis after long-term hemodialysis.

    Science.gov (United States)

    Abuelo, J G; Schwartz, S T; Reginato, A J

    1992-07-01

    A 27-year-old woman undergoing long-term hemodialysis developed cutaneous calcifications on her fingers. A skin biopsy specimen showed that the deposits were calcium oxalate. To our knowledge, only one previous article has reported pathologic and crystallographic studies on calcifications of the skin resulting from dialysis oxalosis. We speculate that vitamin C supplements, liberal tea consumption, an increased serum ionized calcium concentration, and the long duration of hemodialysis contributed to the production of these deposits.

  1. Long term evolution 4G and beyond

    CERN Document Server

    Yacoub, Michel; Figueiredo, Fabrício; Tronco, Tania

    2016-01-01

    This book focus on Long Term Evolution (LTE) and beyond. The chapters describe different aspects of research and development in LTE, LTE-Advanced (4G systems) and LTE-450 MHz such as telecommunications regulatory framework, voice over LTE, link adaptation, power control, interference mitigation mechanisms, performance evaluation for different types of antennas, cognitive mesh network, integration of LTE network and satellite, test environment, power amplifiers and so on. It is useful for researchers in the field of mobile communications.

  2. Consequences of long-term hyperparathyroidism.

    Science.gov (United States)

    Graal, M B; Wolffenbuttel, B H

    1998-07-01

    We describe a young woman with long-term untreated hyperparathyroidism with a superimposed vitamin D deficiency and an extremely decreased bone mineral density that was complicated by a vertebral fracture. Despite pretreatment with intravenous pamidronate and short-term vitamin D supplementation, severe and long-standing hypocalcaemia ('hungry bone syndrome') developed after parathyroidectomy. We discuss the consequences of hyperparathyroidism, especially the effects on bone, the complications of parathyroidectomy and the possibilities of preoperative treatment with bisphosphonates.

  3. Timber joints under long-term loading

    DEFF Research Database (Denmark)

    Feldborg, T.; Johansen, M.

    This report describes tests and results from stiffness and strength testing of splice joints under long-term loading. During two years of loading the spicimens were exposed to cyclically changing relative humidity. After the loading period the specimens were short-term tested. The connectors were...... integral nail-plates and nailed steel and plywood gussets. The report is intended for designers and researchers in timber engineering....

  4. Long-term behaviour of GRP pipes

    OpenAIRE

    Faria, H; A Vieira; Reis, J; Marques, A. T.; Guedes, R.M.; Ferreira, A. J. M.

    2005-01-01

    The main objective of the research programme /1/ described is the study of creep and relaxation behaviour of glass-rein forced thermosetting (GRP) pipes, in order to find alternative methods to predict the long-term properties, rendering a considerable reduction of the time needed for testing and assuring, as far as possible, equivalent reliability when compared to the existing methods. Experimental procedures were performed and are presented here, together with discussion of results, as well...

  5. Long term economic relationships from cointegration maps

    Science.gov (United States)

    Vicente, Renato; Pereira, Carlos de B.; Leite, Vitor B. P.; Caticha, Nestor

    2007-07-01

    We employ the Bayesian framework to define a cointegration measure aimed to represent long term relationships between time series. For visualization of these relationships we introduce a dissimilarity matrix and a map based on the sorting points into neighborhoods (SPIN) technique, which has been previously used to analyze large data sets from DNA arrays. We exemplify the technique in three data sets: US interest rates (USIR), monthly inflation rates and gross domestic product (GDP) growth rates.

  6. Early Life Environments and Long Term Outcomes

    OpenAIRE

    Bolbocean, Corneliu

    2015-01-01

    A large literature has linked “in utero” environment to health and socio-economic outcomes in adulthood. We consider the effect of early life environments on health and skill formation outcomes. We first evaluate the impact of perinatal-neonatal level of technology at birth, which varies across delivery institutions, on the long-term neurodevelopmental outcomes of children with Cerebral Palsy. The level of technology at delivery determines the type of therapy newborns receive immediately afte...

  7. Liquid-type cathode enabled by 3D sponge-like carbon nanotubes for high energy density and long cycling life of Li-S batteries.

    Science.gov (United States)

    Pu, Xiong; Yang, Gang; Yu, Choongho

    2014-11-26

    High energy density and long-term stability of Li-S batteries are achieved by employing a 3D sponge-like carbon nanotube cathode and a liquid-type polysulfide catholyte. Carbon nanotubes not only provide excellent electron pathways and polysulfide reservoirs, but they can also be used as a standalone cathode without current collectors, which greatly alleviates problems arising from insulating sulfur and polysulfide shuttles as well as remarkably increasing the energy density.

  8. 对文莱能长期保持政治社会稳定的几点看法%My Views on Brunei's Long - term Perseverance of its Political and Social Stability

    Institute of Scientific and Technical Information of China (English)

    王云娇

    2005-01-01

    Brunei has its unique features in its politics and society. With this in view, this article tries, from the sociological perspective, to state some views on how it is able to sustain its stability in those two fields.

  9. Variance and invariance of neuronal long-term representations

    Science.gov (United States)

    Clopath, Claudia; Bonhoeffer, Tobias; Hübener, Mark

    2017-01-01

    The brain extracts behaviourally relevant sensory input to produce appropriate motor output. On the one hand, our constantly changing environment requires this transformation to be plastic. On the other hand, plasticity is thought to be balanced by mechanisms ensuring constancy of neuronal representations in order to achieve stable behavioural performance. Yet, prominent changes in synaptic strength and connectivity also occur during normal sensory experience, indicating a certain degree of constitutive plasticity. This raises the question of how stable neuronal representations are on the population level and also on the single neuron level. Here, we review recent data from longitudinal electrophysiological and optical recordings of single-cell activity that assess the long-term stability of neuronal stimulus selectivities under conditions of constant sensory experience, during learning, and after reversible modification of sensory input. The emerging picture is that neuronal representations are stabilized by behavioural relevance and that the degree of long-term tuning stability and perturbation resistance directly relates to the functional role of the respective neurons, cell types and circuits. Using a ‘toy’ model, we show that stable baseline representations and precise recovery from perturbations in visual cortex could arise from a ‘backbone’ of strong recurrent connectivity between similarly tuned cells together with a small number of ‘anchor’ neurons exempt from plastic changes. This article is part of the themed issue ‘Integrating Hebbian and homeostatic plasticity’. PMID:28093555

  10. Long-term policy on gas composition

    Energy Technology Data Exchange (ETDEWEB)

    Verhagen, M.J.M.

    2012-03-13

    This letter sets out the policy of the Dutch cabinet on the long-term change to the composition of low calorific gas that is distributed via the public gas grid. The title of a separate attachment to this letter is 'The composition of low calorific gas in the more distant future and the requirements for gas appliances covered by the Gas Appliances Directive'. The attachment sets out the composition of low calorific gas as network operators can distribute it via the public gas grid from 2021 (or from a later date). This relates to the changes in the 'exit specification' of the gas.

  11. Long-Term Wind Power Variability

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Y. H.

    2012-01-01

    The National Renewable Energy Laboratory started collecting wind power data from large commercial wind power plants (WPPs) in southwest Minnesota with dedicated dataloggers and communication links in the spring of 2000. Over the years, additional WPPs in other areas were added to and removed from the data collection effort. The longest data stream of actual wind plant output is more than 10 years. The resulting data have been used to analyze wind power fluctuations, frequency distribution of changes, the effects of spatial diversity, and wind power ancillary services. This report uses the multi-year wind power data to examine long-term wind power variability.

  12. Long-term effects of sibling incest.

    Science.gov (United States)

    Daie, N; Witztum, E; Eleff, M

    1989-11-01

    Although sexual abuse of children is recognized as a serious problem, sibling incest has received relatively little attention. A distinction has been made between power-oriented sibling incest and nurturance-oriented incest. The authors review the relevant literature and present four clinical examples. The cases illustrate the broad range of sibling incest and demonstrate its effects, including the long-term consequences for the perpetrator. Lasting difficulties in establishing and maintaining close relationships, especially sexual ones, are prominent features of each case. Without denying the occurrences of benign sex-play between siblings, the authors emphasize exploitation and abuse as pathogenic aspects of sibling incest.

  13. Safety of long-term PPI therapy

    DEFF Research Database (Denmark)

    Reimer, Christina

    2013-01-01

    Proton pump inhibitors have become the mainstay of medical treatment of acid-related disorders. Long-term use is becoming increasingly common, in some cases without a proper indication. A large number of mainly observational studies on a very wide range of possible associations have been published...... is based on a relevant indication. The concern for complications should primarily be directed at elderly, malnourished with significant co-morbidity. In this population an increased risk for enteric infections, fractures and nutritional deficiencies might have clinical consequences and should lead...

  14. Long Term Analysis for the BAM device

    Science.gov (United States)

    Bonino, D.; Gardiol, D.

    2011-02-01

    Algorithms aimed at the evaluation of critical quantities are based on models with many parameters, which values are estimated from data. The knowledge, with high accuracy, of these values and the control of their temporal evolution are important features. In this work, we focus on the latter subject, and we show a proposed pipeline for the BAM (Basic Angle Monitoring) Long Term Analysis, aimed at the study of the calibration parameters of the BAM device and of the Basic Angle variation, searching for unwanted trends, cyclic features, or other potential unexpected behaviours.

  15. Long-term space flights - personal impressions

    Science.gov (United States)

    Polyakov, V. V.

    During a final 4-month stage of a 1-year space flight of cosmonauts Titov and Manarov, a physician, Valery Polyakov was included on a crew for the purpose of evaluating their health, correcting physical status to prepare for the spacecraft reentry and landing operations. The complex program of scientific investigations and experiments performed by the physician included an evaluation of adaptation reactions of the human body at different stages of space mission using clinicophysiological and biochemical methods; testing of alternative regimes of exercise and new countermeasures to prevent an unfavourable effect of long-term weightlessness.

  16. Reaction mechanism and thermal stability study on cathode materials for rechargeable lithium ion batteries

    Science.gov (United States)

    Fang, Jin

    Olivine-type lithium iron phosphate has been a very promising cathode material since it was proposed by Padhi in 1997, low-cost, environmental friendly and stable structure ensure the commercialization of LiFePO 4. In LiFePO4, during charge and discharge process, Li ions are transferred between two phases, Li-poor LialphaFePO 4 and Li-rich Li1-betaFePO4, which implies a significant energy barrier for the new phase nucleation and interface growth, contrary to the fast reaction kinetics experimentally observed. The understanding of the lithiation and delithiation mechanism of this material has spurred a lot of research interests. Many theory models have been proposed to explain the reaction mechanism of LiFePO4, among them, the single phase model claims that the reaction goes through a metastable single phase, and the over potential required to form this single phase is about 30mV, so we studied the driving force to transport lithium ions between Lialpha FePO4 and Li1-betaFePO4 phases and compared the particle sizes effect. Experiment results shows that, the nano-sized (30nm) LiFePO4 has wider solid solution range, lower solid solution formation temperature and faster kinetics than normal LiFePO4 (150nm). Also a 20mV over potential was observed in both samples, either after relaxing the FePO4/LiFePO4 system to equilibrium or transport lithium from one side to the other side, the experiment result is corresponding to theoretical calculation; indicates the reaction might go through single-phase reaction mechanism. The energy and power density of lithium ion battery largely depend on cathode materials. Mn substituted LiFePO4 has a higher voltage than LiFePO4, which results a higher theoretical energy density. Safety issue is one of the most important criterions for batteries, since cathode materials need to maintain stable structure during hundreds of charge and discharge cycles and ranges of application conditions. We have reported that iron-rich compound o-Fe1-yMnyPO4

  17. Long-term environmental behaviour of radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Brechignac, F.; Moberg, L.; Suomela, M

    2000-04-01

    The radioactive pollution of the environment results from the atmospheric nuclear weapons testing (during the mid-years of twentieth century), from the development of the civilian nuclear industry and from accidents such as Chernobyl. Assessing the resulting radiation that humans might receive requires a good understanding of the long-term behaviour of radionuclides in the environment. This document reports on a joint European effort to advance this understanding, 3 multinational projects have been coordinated: PEACE, EPORA and LANDSCAPE. This report proposes an overview of the results obtained and they are presented in 6 different themes: (i) redistribution in the soil-plant system, (ii) modelling, (iii) countermeasures, (iv) runoff (v) spatial variations, and (vi) dose assessment. The long term behaviour of the radionuclides {sup 137}Cs, {sup 90}Sr and {sup 239-240}Pu is studied through various approaches, these approaches range from in-situ experiments designed to exploit past contamination events to laboratory simulations. A broad scope of different ecosystems ranging from arctic and boreal regions down to mediterranean ones has been considered. (A.C.)

  18. Pediatric HIV Long-Term Nonprogressors

    Directory of Open Access Journals (Sweden)

    B. H. Rimawi

    2014-01-01

    Full Text Available Patients infected with HIV are best categorized along a continuum from rapid progressors to HIV long-term nonprogressors. Long-term nonprogressors (LTNPs are those in which AIDS develop many years after being infected with HIV, often beyond the 10-year mark, and represent 15–20% of the HIV infected patients. Many of these patients are able to control their infection and maintain undetectable viral loads for long periods of time without antiretroviral therapy. After a comprehensive literature search, we found extensive data related to HIV LTNPs in the adult population; however, very limited data was available related to LTNPs within the pediatric population. We present a case of pediatric HIV LTNPs, perinatally infected patient with undetectable viral loads, despite never receiving ART. Although there are not many instances of LTNPs among children, this child may be one, though she had intermittent viremia. She has continued to manifest serologic evidence of infection, with yearly ELISA and western blot positive tests. Based on the viral fitness studies that were performed, this case exemplifies an adolescent LTNP.

  19. Long Term Changes in the Polar Vortices

    Science.gov (United States)

    Braathen, Geir O.

    2016-04-01

    As the amount of halogens in the stratosphere is slowly declining and the ozone layer slowly recovers it is of interest to see how the meteorological conditions in the vortex develop over the long term since such changes might alter the foreseen ozone recovery. In conjunction with the publication of the WMO Antarctic and Arctic Ozone Bulletins, WMO has acquired the ERA Interim global reanalysis data set for several meteorological parameters. This data set goes from 1979 - present. These long time series of data can be used for several useful studies of the long term development of the polar vortices. Several "environmental indicators" for vortex change have been calculated, and a climatology, as well as trends, for these parameters will be presented. These indicators can act as yardsticks and will be useful for understanding past and future changes in the polar vortices and how these changes affect polar ozone depletion. Examples of indicators are: vortex mean temperature, vortex minimum temperature, vortex mean PV, vortex "importance" (PV*area), vortex break-up time, mean and maximum wind speed. Data for both the north and south polar vortices have been analysed at several isentropic levels from 350 to 850 K. A possible link between changes in PV and sudden stratospheric warmings will be investigated, and the results presented. The unusual meteorological conditions of the 2015 south polar vortex and the 2010/11 and 2015/16 north polar vortices will be compared to other recent years.

  20. Long term effects of Escherichia coli mastitis.

    Science.gov (United States)

    Blum, Shlomo E; Heller, Elimelech D; Leitner, Gabriel

    2014-07-01

    Escherichia coli is one of the most frequently diagnosed causes of bovine mastitis, and is typically associated with acute, clinical mastitis. The objective of the present study was to evaluate the long term effects of intramammary infections by E. coli on milk yield and quality, especially milk coagulation. Twenty-four Israeli Holstein cows diagnosed with clinical mastitis due to intramammary infection by E. coli were used in this study. Mean lactation number, days in milk (DIM) and daily milk yield (DMY) at the time of infection was 3.3 ± 1.3, 131.7 days ± 78.6 and 45.7 L ± 8.4, respectively. DMY, milk constituents, somatic cells count (SCC), differential leukocytes count and coagulation parameters were subsequently assessed. Two patterns of inflammation were identified: 'short inflammation', characterized by 15% decrease in DMY and >30 days to reach a new maximum DMY (n = 19). The estimated mean loss of marketable milk during the study was 200 L/cow for 'short inflammation' cases, and 1,500 L/cow for 'long inflammation' ones. Significant differences between 'short' and 'long inflammation' effects were found in almost all parameters studied. Long-term detrimental effects on milk quality were found regardless of clinical or bacteriological cure of affected glands.

  1. Sleep facilitates long-term face adaptation.

    Science.gov (United States)

    Ditye, Thomas; Javadi, Amir Homayoun; Carbon, Claus-Christian; Walsh, Vincent

    2013-10-22

    Adaptation is an automatic neural mechanism supporting the optimization of visual processing on the basis of previous experiences. While the short-term effects of adaptation on behaviour and physiology have been studied extensively, perceptual long-term changes associated with adaptation are still poorly understood. Here, we show that the integration of adaptation-dependent long-term shifts in neural function is facilitated by sleep. Perceptual shifts induced by adaptation to a distorted image of a famous person were larger in a group of participants who had slept (experiment 1) or merely napped for 90 min (experiment 2) during the interval between adaptation and test compared with controls who stayed awake. Participants' individual rapid eye movement sleep duration predicted the size of post-sleep behavioural adaptation effects. Our data suggest that sleep prevented decay of adaptation in a way that is qualitatively different from the effects of reduced visual interference known as 'storage'. In the light of the well-established link between sleep and memory consolidation, our findings link the perceptual mechanisms of sensory adaptation--which are usually not considered to play a relevant role in mnemonic processes--with learning and memory, and at the same time reveal a new function of sleep in cognition.

  2. Climate Predictability and Long Term Memory

    Science.gov (United States)

    Zhu, X.; Blender, R.; Fraedrich, K.; Liu, Z.

    2010-09-01

    The benefit of climate Long Term Memory (LTM) for long term prediction is assessed using data from a millennium control simulation with the atmosphere ocean general circulation model ECHAM5/MPIOM. The forecast skills are evaluated for surface temperature time series at individual grid points. LTM is characterised by the Hurst exponent in the power-law scaling of the fluctuation function which is determined by detrended fluctuation analysis (DFA). LTM with a Hurst exponent close to 0.9 occurs mainly in high latitude oceans, which are also characterized by high potential predictability. Climate predictability is diagnosed in terms of potentially predictable variance fractions. Explicit prediction experiments for various time steps are conducted on a grid point basis using an auto-correlation (AR1) predictor: in regions with LTM, prediction skills are beyond that expected from red noise persistence; exceptions occur in some areas in the southern oceans and over the northern hemisphere continents. Extending the predictability analysis to the fully forced simulation shows large improvement in prediction skills.

  3. Long term perfusion system supporting adipogenesis.

    Science.gov (United States)

    Abbott, Rosalyn D; Raja, Waseem K; Wang, Rebecca Y; Stinson, Jordan A; Glettig, Dean L; Burke, Kelly A; Kaplan, David L

    2015-08-01

    Adipose tissue engineered models are needed to enhance our understanding of disease mechanisms and for soft tissue regenerative strategies. Perfusion systems generate more physiologically relevant and sustainable adipose tissue models, however adipocytes have unique properties that make culturing them in a perfusion environment challenging. In this paper we describe the methods involved in the development of two perfusion culture systems (2D and 3D) to test their applicability for long term in vitro adipogenic cultures. It was hypothesized that a silk protein biomaterial scaffold would provide a 3D framework, in combination with perfusion flow, to generate a more physiologically relevant sustainable adipose tissue engineered model than 2D cell culture. Consistent with other studies evaluating 2D and 3D culture systems for adipogenesis we found that both systems successfully model adipogenesis, however 3D culture systems were more robust, providing the mechanical structure required to contain the large, fragile adipocytes that were lost in 2D perfused culture systems. 3D perfusion also stimulated greater lipogenesis and lipolysis and resulted in decreased secretion of LDH compared to 2D perfusion. Regardless of culture configuration (2D or 3D) greater glycerol was secreted with the increased nutritional supply provided by perfusion of fresh media. These results are promising for adipose tissue engineering applications including long term cultures for studying disease mechanisms and regenerative approaches, where both acute (days to weeks) and chronic (weeks to months) cultivation are critical for useful insight.

  4. La2NiO4+δ Infiltration of Plasma-Sprayed LSCF Coating for Cathode Performance Improvement

    Science.gov (United States)

    Li, Ying; Zhang, Shan-Lin; Li, Cheng-Xin; Wei, Tao; Yang, Guan-Jun; Li, Chang-Jiu; Liu, Meilin

    2016-01-01

    Perovskite-structured (La0.6Sr0.4Co0.2Fe0.8O3) LSCF has been widely studied as a cathode material for intermediate-temperature solid oxide fuel cells. However, the application of LSCF cathode is likely to be limited by its sluggish surface catalytic properties and long-term stability issues. Oxygen hyper-stoichiometric La2NiO4+δ with K2NiF4 structure exhibits higher catalytic properties, ionic conductivity, and stability in comparison with LSCF cathode. Due to the good chemical compatibility of these two cathode materials, it is possible to prepare a composite cathode by the infiltration of La2NiO4+δ in the porous LSCF. This composite structure fully utilizes the advantages of the two cathodes and enhances the LSCF cathode performance. In this study, the LSCF cathode was deposited by using an atmospheric plasma spray technique, and the porous LSCF cathode was then infiltrated by La2NiO4+δ. The atmospheric plasma spray technique was used to reduce the SOFC manufacturing cost. The microstructure of coatings was characterized by SEM and EDS. The cathode polarization resistance was found to decrease by ~40% after the La2NiO4+δ infiltration. Also, the activation energy decreased from 1.53 to 1.40 eV.

  5. A validated analytical method to study the long-term stability of natural and synthetic glucocorticoids in livestock urine using ultra-high performance liquid chromatography coupled to Orbitrap-high resolution mass spectrometry.

    Science.gov (United States)

    De Clercq, Nathalie; Julie, Vanden Bussche; Croubels, Siska; Delahaut, Philippe; Vanhaecke, Lynn

    2013-08-01

    Due to their growth-promoting effects, the use of synthetic glucocorticoids is strictly regulated in the European Union (Council Directive 2003/74/EC). In the frame of the national control plans, which should ensure the absence of residues in food products of animal origin, in recent years, a higher frequency of prednisolone positive bovine urines has been observed. This has raised questions with respect to the stability of natural corticoids in the respective urine samples and their potential to be transformed into synthetic analogs. In this study, a ultra high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) methodology was developed to examine the stability of glucocorticoids in bovine urine under various storage conditions (up to 20 weeks) and to define suitable conditions for sample handling and storage, using an Orbitrap Exactive™. To this end, an extraction procedure was optimized using a Plackett-Burman experimental design to determine the key conditions for optimal extraction of glucocorticoids from urine. Next, the analytical method was successfully validated according to the guidelines of CD 2002/657/EC. Decision limits and detection capabilities for prednisolone, prednisone and methylprednisolone ranged, respectively, from 0.1 to 0.5μgL(-1) and from 0.3 to 0.8μgL(-1). For the natural glucocorticoids limits of detection and limits of quantification for dihydrocortisone, cortisol and cortisone ranged, respectively, from 0.1 to 0.2μgL(-1) and from 0.3 to 0.8μgL(-1). The stability study demonstrated that filter-sterilization of urine, storage at -80°C, and acidic conditions (pH 3) were optimal for preservation of glucocorticoids in urine and able to significantly limit degradation up to 20 weeks.

  6. Emotional behavior in long-term marriage.

    Science.gov (United States)

    Carstensen, L L; Gottman, J M; Levenson, R W

    1995-03-01

    In exploring the emotional climate of long-term marriages, this study used an observational coding system to identify specific emotional behaviors expressed by middle-aged and older spouses during discussions of a marital problem. One hundred and fifty-six couples differing in age and marital satisfaction were studied. Emotional behaviors expressed by couples differed as a function of age, gender, and marital satisfaction. In older couples, the resolution of conflict was less emotionally negative and more affectionate than in middle-aged marriages. Differences between husbands and wives and between happy and unhappy marriages were also found. Wives were more affectively negative than husbands, whereas husbands were more defensive than wives, and unhappy marriages involved greater exchange of negative affect than happy marriages.

  7. [Enteral nutrition through long-term jejunostomy].

    Science.gov (United States)

    Fernández, T; Neira, P; Enríquez, C

    2008-01-01

    We present the case of a female patient suffering a peritonitis episode after subtotal gastrectomy due to gastric neoplasm in relation to lesser curvature necrosis extending to the anterior esophageal wall. This an uncommon andsevere complication that made mandatory further aggressive surgery: transection of the abdominal esophagus, transection of the gastric stump, and cervical esophagostomy with creation of a jejunostomy with a needle catheter for feeding. This digestive tube access technique is generally used during major abdominal post-surgery until oral intake is reestablished. Our patient has been 187 days with this therapy since reconstruction of the GI tract was ruled out due to tumoral infiltration of the colon and tumor recurrence at the gastrohepatic omentum. To date, there has been no complication from permanence and/or long-term use of this technique.

  8. Long-term variations of solar activity

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Using the Lomb-Scargle periodogram we analyzed two sunspot series: the one over the past 11000 years at the 10-year interval based upon the survey data of 14C concentration in tree-rings, reconstructed by Solanki et al.; and the sunspot number over the past 7000 years, derived from geomagnetic variations by Usoskin et al. We found the periods and quasi-periods in solar activity, such as about 225, 352, 441, 522 and 561 a, and near 1000 and 2000 a. An approach of wavelet transform was applied to check the two sunspot time series, with emphasis on investigating time-varying characteristics in the long-term fluctuations of solar activity. The results show that the lengths and amplitudes of the periods have changed with time, and large variations have taken place during some periods.

  9. Technology for long-term care.

    Science.gov (United States)

    Tak, Sunghee H; Benefield, Lazelle E; Mahoney, Diane Feeney

    2010-01-01

    Severe staff shortages in long-term care (LTC) make it difficult to meet the demands of the growing aging population. Further, technology-savvy Baby Boomers are expected to reshape the current institutional environments toward gaining more freedom and control in their care and lives. Voices from business, academia, research, advocacy organizations, and government bodies suggest that innovative technological approaches are the linchpin that may prepare society to cope with these projected demands. In this article, we review the current state of aging-related technology, identify potential areas for efficacy testing on improving the quality of life of LTC residents in future research, and discuss barriers to implementation of LTC technology. Finally, we present a vision of future technology use that could transform current care practices.

  10. [Femoral angioplasty. Long-term results].

    Science.gov (United States)

    Foucart, H; Carlier, C; Baudrillard, J C; Joffre, F; Cécile, J P

    1990-01-01

    A study on the long-term efficacy of femoral-popliteal angioplasty was carried out on 185 angioplasty cases over a 5 year follow-up period. A classification of data according to the type of lesion treated, revealed that results were favorable in case of stenosis (87%), short obstruction (70%) and long obstruction (35%). A special study of the outcome of treatments for stage IV arteritis was carried out. After comparing results with those obtained by other teams, the authors list the complications encountered, hematomas, and thromboses, and show their current tendency for regression. Lastly, the authors stress the advantages of angioscopy, which permits to identify the nature of the treated lesions and to predict possible complications, which are usually underrated by angiography.

  11. Autobiographical reasoning in long-term fandom

    Directory of Open Access Journals (Sweden)

    C. Lee Harrington

    2010-09-01

    Full Text Available We explore the social psychological processes through which fan-based experiences become situated in fans' larger life narratives. Drawing on original survey data with long-term U.S. soap opera fans, we examine how the psychological mechanism of autobiographical reasoning functions in fans' construction of self-narratives over time. The case study presented here is a subset of a larger investigation into the age-related structure of fans' activities, identities, and interpretive capacities. Situated at the intersections of gerontological (life span/life course theory and contemporary fan studies, our project mines relatively uninvestigated theoretical terrain. We conclude with a brief discussion of implications for future fan studies.

  12. Brodie's abscess. A long-term review.

    Science.gov (United States)

    Stephens, M M; MacAuley, P

    1988-09-01

    In 20 patients with 21 Brodie's abscesses, a long-term review revealed that 13 occurred in the second decade of life. All had local symptoms for six weeks or more. The tibia was involved in 11 cases and seven of these were in the proximal metaphysis. The erythrocyte sedimentation rate (ESR) was elevated in only six cases. When the ESR was more than 40 mm per hour, recurrence was more likely. Staphylococcus aureus was cultured from 11 abscesses. Curettage and antibiotics for six weeks were adequate for treatment in most cases. However, lesions larger than 3 cm in diameter should be grafted, and patients with an elevated ESR require more aggressive decompression and prolonged antibiotic therapy. Lesions within the neck of the femur pose particular anatomic problems and should not be approached laterally. All cases were followed to full bone maturity. No significant leg length inequality was clinically or roentgenologically apparent. If an abscess was juxtaphyseal, deformity of the epiphysis could develop.

  13. Long term results of pneumatic retinopexy

    Directory of Open Access Journals (Sweden)

    Ellakwa AF

    2012-01-01

    Full Text Available Amin F EllakwaMenoufiya University, Shibin el Kom, Al-Menoufiya, EgyptBackground: Rhegmatogenous retinal detachment is a commonly encountered retinal problem where rapid treatment can prevent irreversible vision loss. Pneumatic retinopexy (PR is a simple, minimally invasive procedure for retinal reattachment.Purpose: This study aimed to assess the long-term anatomical and functional outcome of pneumatic retinopexy in primary rhegmatogenous retinal detachment.Patients and methods: A prospective interventional study was performed. Subjects with rhegmatogenous retinal detachment who underwent pneumatic retinopexy from May 2006 to May 2007 at Menoufiya University Hospital were included in this study with at least 3 years follow-up.Results: A total of 40 cases were included in the study. The mean age of patients was 44.25 ± 10.85 years. Reattachment of the retina was achieved in 100% of cases. In 75% of cases, the primary intervention was successful. However, the retina redetached in 20% of these during the first 6 months, requiring reinjection or another procedure. Three years after the first intervention, follow-up measurement of the mean visual acuity of the eyes without reoperation was 0.40 ± 0.21 while the mean visual acuity of the eyes which needed additional operations was 0.22 ± 0.13.Conclusion: Sixty percent of the cases obtained long-term retinal reattachment with a single operation success (SOS, with good visual recovery and less morbidity than other more invasive procedures like scleral buckling or pars plana vitrectomy, translating to higher productivity for the patient. This procedure, being quicker than the alternatives, also saves the surgeon's time, making PR a good choice for managing primary rhegmatogenous retinal detachment in developing countries.Keywords: pneumatic, retinopexy, rhegmatogenous, retinal detachment

  14. Long-term reductions in tinnitus severity

    Directory of Open Access Journals (Sweden)

    Folmer Robert L

    2002-09-01

    Full Text Available Abstract Background This study was undertaken to assess long-term changes in tinnitus severity exhibited by patients who completed a comprehensive tinnitus management program; to identify factors that contributed to changes in tinnitus severity within this population; to contribute to the development and refinement of effective assessment and management procedures for tinnitus. Methods Detailed questionnaires were mailed to 300 consecutive patients prior to their initial appointment at the Oregon Health & Science University Tinnitus Clinic. All patients were then evaluated and treated within a comprehensive tinnitus management program. Follow-up questionnaires were mailed to the same 300 patients 6 to 36 months after their initial tinnitus clinic appointment. Results One hundred ninety patients (133 males, 57 females; mean age 57 years returned follow-up questionnaires 6 to 36 months (mean = 22 months after their initial tinnitus clinic appointment. This group of patients exhibited significant long-term reductions in self-rated tinnitus loudness, Tinnitus Severity Index scores, tinnitus-related anxiety and prevalence of current depression. Patients who improved their sleep patterns or Beck Depression Inventory scores exhibited greater reductions of tinnitus severity scores than patients who continued to experience insomnia and depression at follow-up. Conclusions Individualized tinnitus management programs that were designed for each patient contributed to overall reductions in tinnitus severity exhibited on follow-up questionnaires. Identification and treatment of patients experiencing anxiety, insomnia or depression are vital components of an effective tinnitus management program. Utilization of acoustic therapy also contributed to improvements exhibited by these patients.

  15. Radionuclide Incorporation and Long Term Performance of Apatite Waste Forms

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jianwei [Louisiana State Univ., Baton Rouge, LA (United States); Lian, Jie [Rensselaer Polytechnic Inst., Troy, NY (United States); Gao, Fei [Univ. of Michigan, Ann Arbor, MI (United States)

    2016-01-04

    This project aims to combines state-of-the-art experimental and characterization techniques with atomistic simulations based on density functional theory (DFT) and molecular dynamics (MD) simulations. With an initial focus on long-lived I-129 and other radionuclides such as Cs, Sr in apatite structure, specific research objectives include the atomic scale understanding of: (1) incorporation behavior of the radionuclides and their effects on the crystal chemistry and phase stability; (2) stability and microstructure evolution of designed waste forms under coupled temperature and radiation environments; (3) incorporation and migration energetics of radionuclides and release behaviors as probed by DFT and molecular dynamics (MD) simulations; and (4) chemical durability as measured in dissolution experiments for long term performance evaluation and model validation.

  16. Mechanistic Enhancement of SOFC Cathode Durability

    Energy Technology Data Exchange (ETDEWEB)

    Wachsman, Eric [Univ. of Maryland, College Park, MD (United States)

    2016-02-01

    Durability of solid oxide fuel cells (SOFC) under “real world” conditions is an issue for commercial deployment. In particular cathode exposure to moisture, CO2, Cr vapor (from interconnects and BOP), and particulates results in long-term performance degradation issues. Here, we have conducted a multi-faceted fundamental investigation of the effect of these contaminants on cathode performance degradation mechanisms in order to establish cathode composition/structures and operational conditions to enhance cathode durability.

  17. Apinhamento ântero-superior: revisão e análise crítica da literatura Maxillary crowding and long-term stability: a review of literature

    Directory of Open Access Journals (Sweden)

    Patrícia Paschoal Martins

    2007-04-01

    Full Text Available INTRODUÇÃO: o tratamento do apinhamento dentário da região anterior superior e inferior é comumente acometido pela recidiva, entretanto a maior parte dos estudos aborda apenas a estabilidade do tratamento do arco dentário inferior. OBJETIVO: este artigo propõe uma revisão e análise crítica da literatura, enfatizando os fatores etiológicos do apinhamento dentário, as diversas formas de tratamento e a recidiva no arco superior, considerando o plano de tratamento, os fatores periodontais e a expansão rápida da maxila. CONCLUSÕES: a severidade inicial da má oclusão, as alterações dimensionais dos arcos dentários e as alterações na fisiologia do ligamento periodontal são os principais fatores etiológicos de recidiva. O estudo da etiologia da recidiva permite ao ortodontista o correto planejamento dos casos clínicos e a previsibilidade da estabilidade pós-contenção.INTRODUCTION: The treatment of crowding of maxillary and mandibular anterior teeth commonly suffers relapse. Therefore, major studies focus only on stability of mandibular anterior segment. OBJECTIVE: This article propose a review and critical analysis of the literature, emphasizing the etiologic factors of incisors crowding, the various treatment plans and the relapse of the maxillary anterior segment, considering the treatment protocols, the periodontal factors and the rapid maxillary expansion. CONCLUSIONS: The main factors influencing the relapse are the severity of the initial malocclusion, the changes in arch dimensions and the changes in physiology of periodontal tissue. The study of the causes of relapse is important to help in achieving a correct treatment planning and to predict the postretention stability.

  18. Long-term Stability of Cocaine Hydrochloride Aqueous Solution 50 mg/mL (5%) at Room Temperature and at 5°C ± 3°C in Glass Bottles.

    Science.gov (United States)

    Dewulf, Joseph; Hecq, Jean-Daniel; Huvelle, Sophie; Godet, Marie; Gillet, Patricia; Jamart, Jacques; Galanti, Laurence M

    2015-01-01

    The objective of this study was to investigate the stability of cocaine hydrochloride 50 mg/mL (5%) aqueous solution stored in glass bottles at 5°C ± 3°C or at room temperature. Ten bottles of cocaine hydrochloride 50 mg/mL were prepared under aseptic conditions. Five were stored at 5°C ± 3°C and five at room temperature. pH measurements, optic density measurements at different wave-lengths, and optic microscopic observations were performed periodically during the storage. A forced-degradation test with hydrochloric acid 12M and NaOH 5M with and without heating at 100°C was also performed. The concentrations were measured by high-pressure liquid chromatography with photodiode-array detection. Stability of the solutions was defined as the period for which the one-sided 95% confidence interval of the common regression line remains superior to 90% of the initial concentration as recommended by the U.S. Food and Drug Administration. The forced-degradation tests did not influence the chromatographic peaks of the studied component. No significant change of optic density was seen and no crystals were observed with the optic microscope during the study. The solutions stored at 5°C ± 3°C or at room temperature maintained 90% of their concentration after 24 days. During this period, the pH of the solution decreased from 5.39 to 4.34 at 5°C ± 3°C and from 5.37 to 3.44 at room temperature. In order to alleviate adverse reactions to the eye with too low pH, we propose a period of validity of 15 days at 5°C ± 3°C and 48 hours at room temperature. During this period, the degradation of the preparation was lower than 10%, and the values of pH were higher than 4.0.

  19. Long-term potentiation and long-term depression: a clinical perspective

    Directory of Open Access Journals (Sweden)

    Timothy V.P. Bliss

    2011-01-01

    Full Text Available Long-term potentiation and long-term depression are enduring changes in synaptic strength, induced by specific patterns of synaptic activity, that have received much attention as cellular models of information storage in the central nervous system. Work in a number of brain regions, from the spinal cord to the cerebral cortex, and in many animal species, ranging from invertebrates to humans, has demonstrated a reliable capacity for chemical synapses to undergo lasting changes in efficacy in response to a variety of induction protocols. In addition to their physiological relevance, long-term potentiation and depression may have important clinical applications. A growing insight into the molecular mechanisms underlying these processes, and technological advances in non-invasive manipulation of brain activity, now puts us at the threshold of harnessing long-term potentiation and depression and other forms of synaptic, cellular and circuit plasticity to manipulate synaptic strength in the human nervous system. Drugs may be used to erase or treat pathological synaptic states and non-invasive stimulation devices may be used to artificially induce synaptic plasticity to ameliorate conditions arising from disrupted synaptic drive. These approaches hold promise for the treatment of a variety of neurological conditions, including neuropathic pain, epilepsy, depression, amblyopia, tinnitus and stroke.

  20. Fundamental Investigations and Rational Design of Durable High-Performance SOFC Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu [Georgia Inst. of Technology, Atlanta, GA (United States); Ding, Dong [Georgia Inst. of Technology, Atlanta, GA (United States); Wei, Tao [Georgia Inst. of Technology, Atlanta, GA (United States); Liu, Meilin [Georgia Inst. of Technology, Atlanta, GA (United States)

    2016-03-31

    The main objective of this project is to unravel the degradation mechanism of LSCF cathodes under realistic operating conditions with different types of contaminants, aiming towards the rational design of cathodes with high-performance and enhanced durability by combining a porous backbone (such as LSCF) with a thin catalyst coating. The mechanistic understanding will help us to optimize the composition and morphology of the catalyst layer and microstructure of the LSCF backbone for better performance and durability. More specifically, the technical objectives include: (1) to unravel the degradation mechanism of LSCF cathodes under realistic operating conditions with different types of contaminants using in situ and ex situ measurements performed on specially-designed cathodes; (2) to examine the microstructural and compositional evolution of LSCF cathodes as well as the cathode/electrolyte interfaces under realistic operating conditions; (3) to correlate the fuel cell performance instability and degradation with the microstructural and morphological evolution and surface chemistry change of the cathode under realistic operating conditions; (4) to explore new catalyst materials and electrode structures to enhance the stability of the LSCF cathode under realistic operating conditions; and (5) to validate the long term stability of the modified LSCF cathode in commercially available cells under realistic operating conditions. We have systematically evaluated LSCF cathodes in symmetrical cells and anode supported cells under realistic conditions with different types of contaminants such as humidity, CO2, and Cr. Electrochemical models for the design of test cells and understanding of mechanisms have been developed for the exploration of fundamental properties of electrode materials. It is demonstrated that the activity and stability of LSCF cathodes can be degraded by the introduction of contaminants. The microstructural and compositional evolution of LSCF

  1. LONG-TERM MONITORING SENSOR NETWORK

    Energy Technology Data Exchange (ETDEWEB)

    Stephen P. Farrington; John W. Haas; Neal Van Wyck

    2003-10-16

    Long-term monitoring (LTM) associated with subsurface contamination sites is a key element of Long Term Stewardship and Legacy Management across the Department of Energy (DOE) complex. However, both within the DOE and elsewhere, LTM is an expensive endeavor, often exceeding the costs of the remediation phase of a clean-up project. The primary contributors to LTM costs are associated with labor. Sample collection, storage, preparation, analysis, and reporting can add a significant financial burden to project expense when extended over many years. Development of unattended, in situ monitoring networks capable of providing quantitative data satisfactory to regulatory concerns has the potential to significantly reduce LTM costs. But survival and dependable operation in a difficult environment is a common obstacle to widespread use across the DOE complex or elsewhere. Deploying almost any sensor in the subsurface for extended periods of time will expose it to chemical and microbial degradation. Over the time-scales required for in situ LTM, even the most advanced sensor systems may be rendered useless. Frequent replacement or servicing (cleaning) of sensors is expensive and labor intensive, offsetting most, if not all, of the cost savings realized with unattended, in situ sensors. To enable facile, remote monitoring of contaminants and other subsurface parameters over prolonged periods, Applied Research Associates, Inc has been working to develop an advanced LTM sensor network consisting of three key elements: (1) an anti-fouling sensor chamber that can accommodate a variety of chemical and physical measurement devices based on electrochemical, optical and other techniques; (2) two rapid, cost effective, and gentle means of emplacing sensor packages either at precise locations directly in the subsurface or in pre-existing monitoring wells; and (3) a web browser-based data acquisition and control system (WebDACS) utilizing field-networked microprocessor-controlled smart

  2. Elevated rheumatoid factor and long term risk of rheumatoid arthritis

    DEFF Research Database (Denmark)

    Nielsen, Sune F; Bojesen, Stig E; Schnohr, Peter;

    2012-01-01

    To test whether elevated concentration of rheumatoid factor is associated with long term development of rheumatoid arthritis.......To test whether elevated concentration of rheumatoid factor is associated with long term development of rheumatoid arthritis....

  3. Preparation, characterization and application of alkaline leached CuNiZn ternary coatings for long-term electrolysis in alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Solmaz, Ramazan [Bingoel University, Science and Letters Faculty, Chemistry Department, 12000 Bingoel (Turkey); Doener, Ali; Kardas, Guelfeza [Cukurova University, Science and Letters Faculty, Chemistry Department, 01330 Balcali Adana (Turkey)

    2010-10-15

    The NiCuZn ternary coating was electrochemically deposited on a copper electrode. Then, it was etched in a concentrated alkaline solution (30% NaOH) to produce a porous and electrocatalytic surface suitable for use in the hydrogen evolution reaction (HER). The surface composition of coating before and after alkaline leaching was determined by energy dispersive X-ray (EDX) analysis. The surface morphologies were investigated by scanning electron microscopy (SEM). The long-term stability of electrode prepared for alkaline water electrolysis was investigated in 1 M KOH solution with the help of cathodic current-potential curves and electrochemical impedance spectroscopy (EIS) techniques. It was found that, the NiCuZn coating has a compact and porous structure with good physical stability. Alkaline leaching process further improved the activity of NiCuZn coating in comparison with binary NiCu deposit for the HER. The long-term operation at -100 mA cm{sup -2} showed good electrochemical stability over 120 h. (author)

  4. Synthesis on the spent fuel long term evolution

    Energy Technology Data Exchange (ETDEWEB)

    Ferry, C.; Poinssot, Ch.; Lovera, P.; Poulesquen, A. [CEA Saclay, Dept. de Physico-Chimie (DEN/DPC), 91 - Gif sur Yvette (France); Broudic, V. [CEA Cadarache, Direction des Reacteurs Nucleaires (DRN), 13 - Saint Paul lez Durance (France); Cappelaere, Ch. [CEA Saclay, Dept. des Materiaux pour le Nucleaire(DMN), 91 - Gif-sur-Yvette (France); Desgranges, L. [CEA Cadarache, Direction des Reacteurs Nucleaires (DRN), 13 - Saint-Paul-lez-Durance (France); Garcia, Ph. [CEA Cadarache, Dept. d' Etudes des Combustibles (DEC), 13 - Saint Paul lez Durance (France); Jegou, Ch.; Roudil, D. [CEA Valrho, Dir. de l' Energie Nucleaire (DEN), 30 - Marcoule (France); Lovera, P.; Poulesquen, A. [CEA Saclay, Dept. de Physico-Chimie (DPC), 91 - Gif sur Yvette (France); Marimbeau, P. [CEA Cadarache, Dir. de l' Energie Nucleaire (DEN), 13 - Saint-Paul-lez-Durance (France); Gras, J.M.; Bouffioux, P. [Electricite de France (EDF), 75 - Paris (France)

    2005-07-01

    The French research on spent fuel long term evolution has been performed by CEA (Commissariat a l'Energie Atomique) since 1999 in the PRECCI project with the support of EDF (Electricite de France). These studies focused on the spent fuel behaviour under various conditions encountered in dry storage or in deep geological disposal. Three main types of conditions were discerned: - The evolution in a closed system which corresponds to the normal scenario in storage and to the first confinement phase in disposal; - The evolution in air which corresponds to an incidental loss of confinement during storage or to a rupture of the canister before the site re-saturation in geological disposal; - The evolution in water which corresponds to the normal scenario after the breaching of the canister in repository conditions. This document produced in the frame of the PRECCI project is an overview of the state of knowledge in 2004 concerning the long-term behavior of spent fuel under these various conditions. The state of the art was derived from the results obtained under the PRECCI project as well as from a review of the literature and of data acquired under the European project on Spent Fuel Stability under Repository Conditions. The main results issued from the French research are underlined. (authors)

  5. CERN Services for Long Term Data Preservation

    CERN Document Server

    Shiers, Jamie; Blomer, Jakob; Ganis, Gerardo; Dallmeier-Tiessen, Sunje; Simko, Tibor; Cancio Melia, German; CERN. Geneva. IT Department

    2016-01-01

    In this paper we describe the services that are offered by CERN for Long Term preservation of High Energy Physics (HEP) data, with the Large Hadron Collider (LHC) as a key use case. Data preservation is a strategic goal for European High Energy Physics (HEP), as well as for the HEP community worldwide and we position our work in this global content. Specifically, we target the preservation of the scientific data, together with the software, documentation and computing environment needed to process, (re-)analyse or otherwise (re-)use the data. The target data volumes range from hundreds of petabytes (PB – 10^15 bytes) to hundreds of exabytes (EB – 10^18 bytes) for a target duration of several decades. The Use Cases driving data preservation are presented together with metrics that allow us to measure how close we are to meeting our goals, including the possibility for formal certification for at least part of this work. Almost all of the services that we describe are fully generic – the exception being A...

  6. Downlink Scheduling in Long Term Evolution

    Directory of Open Access Journals (Sweden)

    Anwar Hossain

    2015-06-01

    Full Text Available This is an investigated research article on resource block scheduling of Long Term Evolution (LTE. LTE is one of the evolutions of the Universal Mobile Telecommunication System (UMTS. It provides internet access to mobile users through smart phone, laptop and other android devices. LTE offers a high speed data and multimedia services. It supports data rates up to 100 Mbps in the downlink and 50 Mbps in the uplink transmission. Our research investigation was aim to the downlink scheduling. We have considered The Best CQI scheduling algorithm and the Round Robin scheduling algorithm. The implementation, analysis and comparison of these scheduling algorithms have been performed through MATLAB simulator. We have analyzed the impact of the scheduling schemes on the throughput and the fairness of both scheduling schemes. Here we have proposed a new scheduling algorithm that achieves a compromise between the throughput and the fairness. Orthogonal Frequency Division Multiplexing (OFDM has been adopted as the downlink transmission scheme. We have considered the impact of the channel delay on the throughput. In addition, MIMO transceiver systems have been implemented to increase the throughput

  7. Long Term Evolution of Plasma Wakefields

    CERN Document Server

    Sahai, Aakash A; Tsung, F S; Mori, W B

    2014-01-01

    We study the long-term evolution (LTE) of plasma wakefields over multiple plasma-electron periods and few plasma-ion periods, much less than a recombination time. The evolution and relaxation of such a wakefield-perturbed plasma over these timescales has important implications for the upper limits of repetition-rates in plasma colliders. Intense fields in relativistic lasers (or intense beams) create plasma wakefields (modes around {\\omega}pe) by transferring energy to the plasma electrons. Charged-particle beams in the right phase may be accelerated with acceleration/focusing gradients of tens of GeV/m. However, wakefields leave behind a plasma not in equilibrium, with a relaxation time of multiple plasma-electron periods. Ion motion over ion timescales, caused by energy transfer from the driven plasma-electrons to the plasma-ions can create interesting plasma states. Eventually during LTE, the dynamics of plasma de-coheres (multiple modes through instability driven mixing), thermalizing into random motion (...

  8. Long-term data storage in diamond

    Science.gov (United States)

    Dhomkar, Siddharth; Henshaw, Jacob; Jayakumar, Harishankar; Meriles, Carlos A.

    2016-01-01

    The negatively charged nitrogen vacancy (NV−) center in diamond is the focus of widespread attention for applications ranging from quantum information processing to nanoscale metrology. Although most work so far has focused on the NV− optical and spin properties, control of the charge state promises complementary opportunities. One intriguing possibility is the long-term storage of information, a notion we hereby introduce using NV-rich, type 1b diamond. As a proof of principle, we use multicolor optical microscopy to read, write, and reset arbitrary data sets with two-dimensional (2D) binary bit density comparable to present digital-video-disk (DVD) technology. Leveraging on the singular dynamics of NV− ionization, we encode information on different planes of the diamond crystal with no cross-talk, hence extending the storage capacity to three dimensions. Furthermore, we correlate the center’s charge state and the nuclear spin polarization of the nitrogen host and show that the latter is robust to a cycle of NV− ionization and recharge. In combination with super-resolution microscopy techniques, these observations provide a route toward subdiffraction NV charge control, a regime where the storage capacity could exceed present technologies.

  9. Long-term predictions using natural analogues

    Energy Technology Data Exchange (ETDEWEB)

    Ewing, R.C. [Univ. of New Mexico, Albuquerque, NM (United States)

    1995-09-01

    One of the unique and scientifically most challenging aspects of nuclear waste isolation is the extrapolation of short-term laboratory data (hours to years) to the long time periods (10{sup 3}-10{sup 5} years) required by regulatory agencies for performance assessment. The direct validation of these extrapolations is not possible, but methods must be developed to demonstrate compliance with government regulations and to satisfy the lay public that there is a demonstrable and reasonable basis for accepting the long-term extrapolations. Natural systems (e.g., {open_quotes}natural analogues{close_quotes}) provide perhaps the only means of partial {open_quotes}validation,{close_quotes} as well as data that may be used directly in the models that are used in the extrapolation. Natural systems provide data on very large spatial (nm to km) and temporal (10{sup 3}-10{sup 8} years) scales and in highly complex terranes in which unknown synergisms may affect radionuclide migration. This paper reviews the application (and most importantly, the limitations) of data from natural analogue systems to the {open_quotes}validation{close_quotes} of performance assessments.

  10. Long-term outcome of neuroparacoccidioidomycosis treatment

    Directory of Open Access Journals (Sweden)

    Fabio Francesconi

    2011-02-01

    Full Text Available INTRODUCTION: Neuroparacoccidioidomycosis (NPCM is a term used to describe the invasion of the central nervous system by the pathogenic fungus Paracoccidioides brasiliensis. NPCM has been described sporadically in some case reports and small case series, with little or no focus on treatment outcome and long-term follow-up. METHODS: All patients with NPCM from January 1991 to December 2006 were analyzed and were followed until December 2009. RESULTS: Fourteen (3.8% cases of NPCM were identified out of 367 patients with paracoccidioidomycosis (PCM. A combination of oral fluconazole and sulfamethoxazole/trimethoprim (SMZ/TMP was the regimen of choice, with no documented death due to Paracoccidioides brasiliensis infection. Residual neurological deficits were observed in 8 patients. Residual calcification was a common finding in neuroimaging follow-up. CONCLUSIONS: All the patients in this study responded positively to the association of oral fluconazole and sulfamethoxazole/trimethoprim, a regimen that should be considered a treatment option in cases of NPCM. Neurological sequela was a relatively common finding. For proper management of these patients, anticonvulsant treatment and physical therapy support were also needed.

  11. Long-term corrosion testing pan.

    Energy Technology Data Exchange (ETDEWEB)

    Wall, Frederick Douglas; Brown, Neil R. (Los Alamos National Laboratory, Los Alamos, NM)

    2008-08-01

    This document describes the testing and facility requirements to support the Yucca Mountain Project long-term corrosion testing needs. The purpose of this document is to describe a corrosion testing program that will (a) reduce model uncertainty and variability, (b) reduce the reliance upon overly conservative assumptions, and (c) improve model defensibility. Test matrices were developed for 17 topical areas (tasks): each matrix corresponds to a specific test activity that is a subset of the total work performed in a task. A future document will identify which of these activities are considered to be performance confirmation activities. Detailed matrices are provided for FY08, FY09 and FY10 and rough order estimates are provided for FY11-17. Criteria for the selection of appropriate test facilities were developed through a meeting of Lead Lab and DOE personnel on October 16-17, 2007. These criteria were applied to the testing activities and recommendations were made for the facility types appropriate to carry out each activity. The facility requirements for each activity were assessed and activities were identified that can not be performed with currently available facilities. Based on this assessment, a total of approximately 10,000 square feet of facility space is recommended to meet all future testing needs, given that all testing is consolidated to a single location. This report is a revision to SAND2007-7027 to address DOE comments and add a series of tests to address NWTRB recommendations.

  12. Long-term corrosion testing plan.

    Energy Technology Data Exchange (ETDEWEB)

    Wall, Frederick Douglas; Brown, Neil R. (Los Alamos National Laboratory, Los Alamos, NM)

    2009-02-01

    This document describes the testing and facility requirements to support the Yucca Mountain Project long-term corrosion testing program. The purpose of this document is to describe a corrosion testing program that will (a) reduce model uncertainty and variability, (b) reduce the reliance upon overly conservative assumptions, and (c) improve model defensibility. Test matrices were developed for 17 topical areas (tasks): each matrix corresponds to a specific test activity that is a subset of the total work performed in a task. A future document will identify which of these activities are considered to be performance confirmation activities. Detailed matrices are provided for FY08, FY09 and FY10 and rough order estimates are provided for FY11-17. Criteria for the selection of appropriate test facilities were developed through a meeting of Lead Lab and DOE personnel on October 16-17, 2007. These criteria were applied to the testing activities and recommendations were made for the facility types appropriate to carry out each activity. The facility requirements for each activity were assessed and activities were identified that can not be performed with currently available facilities. Based on this assessment, a total of approximately 10,000 square feet of facility space is recommended to accommodate all future testing, given that all testing is consolidated to a single location. This report is a revision to SAND2008-4922 to address DOE comments.

  13. DIFFERENTIAL DIAGNOSIS OF LONG TERM TONGUE ULCERS

    Directory of Open Access Journals (Sweden)

    Hegde Nidarsh D.

    2012-08-01

    Full Text Available Oral ulcers is a very common disorder of the oral mucosa. Patients with signs or symptoms of oral ulcers are sometimes referred to gastroenterology clinics, however, in most instances the ulcers does not reflect gastrointestinal disease, some with a chronic non- healing ulcer are advised biopsy. Indeed, a spectrum of disorders can give rise to oral mucosal ulcers ranging from minor local trauma to significant local disease such as malignancy or systemic illness. Lesions of the tongue have a broad differential diagnosis ranging from benign idiopathic processes to infections, cancers, and infiltrative disorders. This article will focus on common ulcerative disorders of the tongue in aspects of their clinical features and differential diagnosis, two case reports with the diagnosis and conservative management for long-term chronic ulcers. The two cases which are reported in this article had a differential diagnosis of Squamous cell carcinoma of the tongue. The clinical picture was craterlike lesion, having a velvety-red base and a rolled, indurated border and most important painless in both cases. Removal of the irritant which was the tooth, rehabilitation of the oral mucosa by lubrication with Cocus Nucifera resulted in the healing of the ulcers. Functional components of Cocus Nucifera are Squaline, tocopherol, phytosterols and other sterols which are all plant steroids.

  14. CHARACTERISTICS OF LONG-TERM UNEMPLOYMENT SPELLS IN ROMANIA

    OpenAIRE

    Daniela-Emanuela Danacica; Raluca Mazilescu

    2012-01-01

    The aim of this paper is to analyze characteristics of long-term unemployment spells in Romania and to estimate the effect of factors influencing long-term unemployment spells. The study period is in between January 1st 2008 and December 31st 2010. 468159 long-term spells registered in the specified period at the National Agency of Employment are analyzed.

  15. TIA and Stroke: the long-term perspective

    NARCIS (Netherlands)

    Wijk, I. van

    2006-01-01

    Background Survival after stroke has improved, but little is known about the long-term risk of new vascular events and the functioning of long-term survivors. The main objective of this thesis was to evaluate the long-term perspective of these patients. Methods Two longitudinal studies were carried

  16. Clinical and research progress on the treatment effect and the long term stability of cleft lip and palate patients with maxillary hypoplasia during prepuberty%青春期早期唇腭裂继发上颌发育不足的治疗及其长期稳定性的临床研究进展

    Institute of Scientific and Technical Information of China (English)

    胡心怡

    2011-01-01

    Maxillary protraction and distraction osteogenesis are commonly used in cleft lip and palate patients with maxillary hypoplasia during prepuberty. The effect of the former one is dealing with the timing and the appliance selected while the latter one is associated with the types of distraction osteogenesis including face mask distraction, rigid external distraction and internal distraction. The long term stability of both treatment techniques is still under controversy. This paper reviews the effect and long term stability of the maxillary protraction and distraction osteogenesis.%上颌前方牵引技术和牵张成骨技术前移上颌骨,是目前常用的治疗青春期早期唇腭裂继发上颌发育不足患者的2种方法.上颌前方牵引技术的疗效主要与其牵引时机、牵引装置相关,而关于其治疗后的长期稳定性尚存在争议.牵张成骨技术的疗效主要与其不同的牵张方式有关,包括面罩式牵引、坚固外固定牵引和内置式牵引3种,而有关该治疗技术的长期稳定性也与其牵张方式相关.现本文就这2种常用治疗技术的疗效及其长期稳定性的临床研究进展作一综述.

  17. Scientific Understanding from Long Term Observations: Insights from the Long Term Ecological Research (LTER) Program

    Science.gov (United States)

    Gosz, J.

    2001-12-01

    The network dedicated to Long Term Ecological Research (LTER) in the United States has grown to 24 sites since it was formed in 1980. Long-term research and monitoring are performed on parameters thatare basic to all ecosystems and are required to understand patterns, processes, and relationship to change. Collectively, the sites in the LTER Network provide opportunities to contrast marine, coastal, and continental regions, the full range of climatic gradients existing in North America, and aquatic and terrestrial habitats in a range of ecosystem types. The combination of common core areas and long-term research and monitoring in many habitats have allowed unprecedented abilities to understand and compare complex temporal and spatial dynamics associated with issues like climate change, effects of pollution, biodiversity and landuse. For example, McMurdo Dry Valley in the Antarctic has demonstrated an increase in glacier mass since 1993 which coincides with a period of cooler than normal summers and more than average snowfall. In contrast, the Bonanza Creek and Toolik Lake sites in Alaska have recorded a warming period unprecedented in the past 200 years. Nitrogen deposition effects have been identified through long-term watershed studies on biogeochemical cycles, especially at Coweeta Hydrological Lab, Harvard Forest, and the Hubbard Brook Experimental Forest. In aquatic systems, such as the Northern Temperate Lakes site, long-term data revealed time lags in effects of invaders and disturbance on lake communities. Biological recovery from an effect such as lake acidification was shown to lag behind chemical recovery. The long-term changes documented over 2 decades have been instrumental in influencing management practices in many of the LTER areas. In Puerto Rico, the Luquillo LTER demonstrated that dams obstruct migrations of fish and freshwater shrimp and water abstraction at low flows can completely obliterate downstream migration of juveniles and damage

  18. Electrodeposited synthesis of self-supported Ni-P cathode for efficient electrocatalytic hydrogen generation

    Institute of Scientific and Technical Information of China (English)

    Ruixian Wu; Yuming Dong n; Pingping Jiang; Guangli Wang; Yanmei Chen; Xiuming Wu

    2016-01-01

    One of the key challenges for electrochemical water splitting is the development of low-cost and efficient hydrogen evolution cathode. In this work, a self-supported Ni-P cathode was synthesized by a facile electrodeposition method. The composition and morphology were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. The Ni-P cathode performed low onset over-potential, good catalytic activity and long-term stability under neutral and alkaline conditions. The mechanism of Ni-P electrode for hydrogen production was discussed by electrochemical impedance spectroscopy. The excellent performance of Ni-P cathode was mainly attributed to the synergistic effect of phosphate anions and the self-supported feature.

  19. Electrodeposited synthesis of self-supported Ni-P cathode for efficient electrocatalytic hydrogen generation

    Directory of Open Access Journals (Sweden)

    Ruixian Wu

    2016-06-01

    Full Text Available One of the key challenges for electrochemical water splitting is the development of low-cost and efficient hydrogen evolution cathode. In this work, a self-supported Ni-P cathode was synthesized by a facile electrodeposition method. The composition and morphology were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. The Ni-P cathode performed low onset over-potential, good catalytic activity and long-term stability under neutral and alkaline conditions. The mechanism of Ni-P electrode for hydrogen production was discussed by electrochemical impedance spectroscopy. The excellent performance of Ni-P cathode was mainly attributed to the synergistic effect of phosphate anions and the self-supported feature.

  20. Long-term Durability of Cement-based Materials with Very Low w/b

    Institute of Scientific and Technical Information of China (English)

    XIE Youjun; LIU Yunhua; LONG Guangeheng

    2008-01-01

    To investigate the durability, especially the long-term stability of cement-based materials with very low w/b, the air permeability test, carbonation test, capillary absorption rate test and dilation Dotential test were adopted under long-term heat treatment condition. Microstructure of these materials is also analyzed by scannmg electronic microscopy (SEM) and mercury intrusion porosimeter (MIP) in order to further unveil its mechanism and interrelation between microstructure and its properties. The results indicate that in the area investigated, cement-based material with w/b 0.17, like RPC, possesses low porosity and excellent durability. Moreover, its porosity will further decrease under long-term heat treatment compared with normal heat treatment. Its long-term durability is much superior to that of other cement-based materials with w/b 0.25 or 0.35 as high strength concrete (HSC).

  1. Nutritional deficit and Long Term Potentiation alterations

    Directory of Open Access Journals (Sweden)

    M. Petrosino

    2009-01-01

    Full Text Available In the present work we examined the ability of prenatally malnourished offspring to produce and maintain long-term potentiation (LTP of the perforant path/dentate granule cell synapse in freely moving rats at 15,30, and 90 days of age. Population spike amplitude (PSA was calculated from dentate field potential recordings prior to and at 15, 30, 60 min. and 3, 5, 18 and 24 h following tetanization of the perforant pathway. All animals of both malnourished and well-nourished diet groups at 15 days of age showed potentiation of PSA measures but the measures obtained from 15-day-old prenatally malnourished animals were significantly less than that of age-matched, well-nourished controls. At 30 days of age, remarkable effect of tetanization was likely observed from PSA measures for this age group followed much the same pattern. At 90 days of age, PSA measures obtained from malnourished animals decreased from pretetanization levels immediately following tetanization. At this age, however, at three hours time recordings, this measure growing up to a level which did not differ significantly from that of the control group. These results indicate that the width of tetanization induced enhancement of dentate granule cell response in preweanling rats (15-day-old animals is signifacantly affected fromgestational protein malnutrition and this trend is kept in animals tested at 30 and 90 days of age. The fact, however, that considerable limitation in LTP generation was gained from prenatally malnourished animals at 90 days of age, implying that dietary rehabilitation starting at birth is an intervention strategy not capable to imbrove the effects of the gestational stress.

  2. Long term cultivation of larger benthic Foraminifera

    Science.gov (United States)

    Wöger, Julia; Eder, Wolfgang; Kinoshita, Shunichi; Antonino, Briguglio; Carles, Ferrandes-Cañadell; Hohenegger, Johann

    2015-04-01

    Benthic Foraminifera are used in a variety of applications employing numerous different methods, i.e. ecological monitoring, studying the effects of ocean acidification, reconstructing palaeo-bathymetry or investigating palaeo-salinity and palaeo-temperature to name only a few. To refine our understanding of ecological influences on larger benthic foraminiferal biology and to review inferences from field observations, culture experiments have become an indispensable tool. While culture experiments on smaller benthic foraminifera have become increasingly frequent in the past century, reports of the cultivation of symbiont bearing larger Foraminifera are rare. Generally, cultivation experiments can be divided into two groups: Culturing of populations and cultivation of single specimens allowing individual investigation. The latter differ form the former by several restrictions resulting from the need to limit individual motility without abridging microenvironmental conditions in the Foraminiferans artificial habitat, necessary to enable the individual to development as unfettered as possible. In this study we present first experiences and preliminary results of the long-term cultivation of larger benthic Foraminifera conducted at the 'Tropical Biosphere Research Station Sesoko Island, University of the Ryukyus', Japan, trying to reproduce natural conditions as closely as possible. Individuals of three species of larger benthic Foraminifera (Heterostegina depressa, Palaeonummulites venosus and Operculina complanata) have been cultured since April 2014. At the time of the general assembly the cultivation experiments will have been going on for more than one year, with the aim to investigate growth rates, longevities and reproduction strategies for comparison with results statistically inferred from application of the of the 'natural laboratory' method. The most important factor influencing foraminiferal health and development was found to be light intensity and light

  3. Hormonal changes during long-term isolation.

    Science.gov (United States)

    Custaud, M A; Belin de Chantemele, E; Larina, I M; Nichiporuk, I A; Grigoriev, A; Duvareille, M; Gharib, C; Gauquelin-Koch, G

    2004-05-01

    Confinement and inactivity induce considerable psychological and physiological modifications through social and sensory deprivation. The aim of the SFINCSS-99 experiment was to determine the cardiovascular and hormonal pattern of blood volume regulation during long-term isolation and confinement. Simulation experiments were performed in pressurized chambers similar in size to the volumes of modern space vehicles. Group I consisted of four Russian male volunteers, who spent 240 days in a 100-m(3 )chamber. Group II included four males (one German and three Russians) who spent 110 days in isolation (200-m(3) module). The blood samples, taken before, during and after the isolation period, were used to determine haematocrit (Ht), growth hormone (GH), active renin, aldosterone, and osmolality levels. From the urine samples, electrolytes, osmolality, nitrites, nitrates, cortisol, antidiuretic hormone (ADH), aldosterone, normetanephrine and metanephrine levels were determined. The increase in plasma volume (PV) that is associated with a tendency for a decrease in plasma active renin is likely to be due to decreased sympathetic activity, and concords with the changes in urinary catecholamine levels during confinement. Urinary catecholamine levels were significantly higher during the recovery period than during confinement. This suggests that the sympathoadrenal system was activated, and concords with the increase in heart rate. Vascular resistance is determined by not only the vasoconstrictor but also vasodilator systems. The ratio of nitrite/nitrate in urine, as an indicator of nitric oxide release, did not reveal any significant changes. Analysis of data suggests that the duration of the isolation was a main factor involved in the regulation of hormones.

  4. Perinatal respiratory infections and long term consequences

    Directory of Open Access Journals (Sweden)

    Luciana Indinnimeo

    2015-10-01

    Full Text Available Respiratory syncytial virus (RSV is the most important pathogen in the etiology of respiratory infections in early life. 50% of children are affected by RSV within the first year of age, and almost all children become infected within two years. Numerous retrospective and prospective studies linking RSV and chronic respiratory morbidity show that RSV bronchiolitis in infancy is followed by recurrent wheezing after the acute episod. According to some authors a greater risk of wheezing in children with a history of RSV bronchiolitis would be limited to childhood, while according to others this risk would be extended into adolescence and adulthood. To explain the relationship between RSV infection and the development of bronchial asthma or the clinical pathogenetic patterns related to a state of bronchial hyperreactivity, it has been suggested that RSV may cause alterations in the response of the immune system (immunogenic hypothesis, activating directly mast cells and basophils and changing the pattern of differentiation of immune cells present in the bronchial tree as receptors and inflammatory cytokines. It was also suggested that RSV infection can cause bronchial hyperreactivity altering nervous airway modulation, acting on nerve fibers present in the airways (neurogenic hypothesis.The benefits of passive immunoprophylaxis with palivizumab, which seems to represent an effective approach in reducing the sequelae of RSV infection in the short- and long-term period, strengthen the implementation of prevention programs with this drug, as recommended by the national guidelines of the Italian Society of Neonatology. Proceedings of the 11th International Workshop on Neonatology and Satellite Meetings · Cagliari (Italy · October 26th-31st, 2015 · From the womb to the adultGuest Editors: Vassilios Fanos (Cagliari, Italy, Michele Mussap (Genoa, Italy, Antonio Del Vecchio (Bari, Italy, Bo Sun (Shanghai, China, Dorret I. Boomsma (Amsterdam, the

  5. A new long-term care manifesto.

    Science.gov (United States)

    Kane, Robert L

    2015-04-01

    This article argues for a fresh look at how we provide long-term care (LTC) for older persons. Essentially, LTC offers a compensatory service that responds to frailty. Policy debate around LTC centers on costs, but we are paying for something we really don't want. Building societal enthusiasm (or even support) for LTC will require re-inventing and re-branding. LTC has three basic components: personal care, housing, and health care (primarily chronic disease management). They can be delivered in a variety of settings. It is rare to find all three done well simultaneously. Personal care (PC) needs to be both competent and compassionate. Housing must provide at least minimal amenities and foster autonomy; when travel time for PC raises costs dramatically, some form of clustered housing may be needed. Health care must be proactive, aimed at preventing exacerbations of chronic disease and resultant hospitalizations. Enhancing preferences means allowing taking informed risks. Payment incentives should reward both quality of care and quality of life, but positive outcomes must be defined as slowing decline. Paying for services but not for housing under Medicaid would automatically level the playing field between nursing homes (NH) and community-based services. Regulations should achieve greater parity between NH and community care and include both positive and negative feedback. Providing post-acute care should be separate from LTC. Using the tripartite LTC framework, we can create innovative flexible approaches to providing needed services for frail older persons in formats that are both desirable and affordable. Such care will be more socially desirable and hence worth paying for.

  6. Vertebral sarcoidosis: long-term follow-up with MRI

    Energy Technology Data Exchange (ETDEWEB)

    Lefere, M. [University Hospitals Gasthuisberg, Department of Radiology, Leuven (Belgium); Larbi, A.; Malghem, J.; Vande Berg, B.; Dallaudiere, B. [University Hospitals St Luc, Department of Radiology, Brussels (Belgium)

    2014-08-15

    Vertebral involvement in sarcoidosis is rare and its clinical and imaging features are non-specific. Indeed, because the lesions are hard to differentiate from metastatic disease based on imaging alone, a histological confirmation is advised. Fatty replacement is a well-known finding indicating stabilization and healing in both benign and malignant conditions. It can be used as an indicator of a favorable disease course and response to treatment. We report the case of a 43-year-old woman with multifocal vertebral sarcoidosis lesions and long-term follow-up showing progressive and gradual fatty involution on magnetic resonance imaging (MRI) during 4 years of steroid treatment with a final favorable outcome. (orig.)

  7. A long-term degradation study of power generation characteristics of anode-supported solid oxide fuel cells using LaNi(Fe)O{sub 3} electrode

    Energy Technology Data Exchange (ETDEWEB)

    Komatsu, Takeshi; Watanabe, Kimitaka; Arakawa, Masayasu; Arai, Hajime [NTT Corporation, NTT Energy and Environment Systems Laboratories, Morinosato-Wakamiya 3-1, Atsugi-shi, Kanagawa 243-0198 (Japan)

    2009-09-05

    The long-term operation of an anode-supported solid oxide fuel cell was examined to study the degradation factor. The cell was constructed using LaNi{sub 0.6}Fe{sub 0.4}O{sub 3} (LNF), alumina-doped scandia stabilized zirconia (SASZ), and NiO-SASZ as the cathode, electrolyte, and anode respectively. The cell had Pt current collectors and was operated for 6500 h. The test was carried out at 1073 K with a constant load of 0.4 A cm{sup -2} and included thermal cycling. The cell voltage degradation rate was below 0.86%/1000 h when the cell was operated for up to 5200 h. Changes in the resistance of the cells during the experiments were analyzed by impedance spectroscopy. The cathode polarization resistance and ohmic resistance increased with time. The elements (Si and B) contained in the water condensed from the cathode exhaust gas were identified using inductively coupled plasma (ICP). (author)

  8. Long term stability of rat sleep quantified by microcomputer analysis.

    Science.gov (United States)

    Vivaldi, E A; Pastel, R H; Fernstrom, J D; Hobson, J A

    1984-09-01

    An inexpensive microcomputer system is described for the direct recording of electrographic data from animals. Using this system, electrographic data can be recorded continuously on a polygraph and simultaneously quantitated by the computer, for days or weeks. Our system quantifies the amounts of delta waves, spindle bursts, hippocampal RSA activity and movement spikes for 15 sec epochs. These electrographic data are stored by the computer and subsequently can be used to score sleep stages. We find that the computer reliably counts waves; using these data, it can then score sleep stages off-line with about 90% accuracy. With this system, we find that the minutes/hour of both SWS and REM are remarkably stable from day to day. The absolute number of delta waves, spindle bursts, trains of RSA and movement counts/hour also remain stable from day to day. This type of system should find significant application in situations where quantitation of longterm effects of drugs, diets and other environmental inputs on sleep states or EEG wave bands are of interest.

  9. SLHCV3.0: layout, optics and long term stability

    CERN Document Server

    De Maria, R

    2010-01-01

    SLHCV3.0 is a proof-of-principle scenario for upgrading the luminosity of the LHC. It represents an attempt to overcome the limitations of the Phase I upgrade project proposed layout (corre- sponding to SLHCV2.0) and it aims at a substantial luminosity improvement with a minimum set of hardware changes. In this paper we describe the implementation details of SLHCV3.0, the required changes with respect to the nominal LHC, and the expected performance in terms of chromatic aberrations and dynamic aperture.

  10. Long-Term Stability of Planets in Binary Systems

    CERN Document Server

    Holman, M; Holman, Matthew; Wiegert, Paul

    1999-01-01

    A simple question of celestial mechanics is investigated: in what regions of phase space near a binary system can planets persist for long times? The planets are taken to be test particles moving in the field of an eccentric binary system. A range of values of the binary eccentricity and mass ratio is studied, and both the case of planets orbiting close to one of the stars, and that of planets outside the binary orbiting the system's center of mass, are examined. From the results, empirical expressions are developed for both 1) the largest orbit around each of the stars, and 2) the smallest orbit around the binary system as a whole, in which test particles survive the length of the integration (10^4 binary periods). The empirical expressions developed, which are roughly linear in both the mass ratio mu and the binary eccentricity e, are determined for the range 0.0 <= e <= 0.7-0.8 and 0.1 <= mu <= 0.9 in both regions, and can be used to guide searches for planets in binary systems. After consideri...

  11. Stability of Schmallenberg virus during long-term storage.

    Science.gov (United States)

    Wernike, Kerstin; Beer, Martin

    2016-01-01

    Schmallenberg virus (SBV), a novel insect-transmitted orthobunyavirus that infects ruminants, caused a large epidemic in European livestock since its emergence in 2011. For the in vitro characterization of this hitherto unknown virus as well as for antibody detection tests like indirect immunofluorescence and neutralization test infectious virus is necessary. To determine the most suitable storage temperature, culture-grown SBV was kept at 37°C, 28°C, 4°C, -20°C and -70°C for up to one year. A storage at 37°C led to a complete loss of infectivity within days and at 28°C within a few weeks. When stored at 4°C the infectious titer decreased dependent on the starting quantity, whereas the viral titer was almost constant for a month at -20°C and remained constant for the study period when stored at -70°C. Consequently, SBV should be kept at -70°C, if retention of infectivity is required.

  12. Investigation of long term stability in metal hydrides

    Science.gov (United States)

    Marmaro, Roger W.; Lynch, Franklin E.; Chandra, Dhanesh; Lambert, Steve; Sharma, Archana

    1991-01-01

    It is apparent from the literature and the results of this study that cyclic degradation of AB(5) type metal hydrides varies widely according to the details of how the specimens are cycled. The Rapid Cycle Apparatus (RCA) used produced less degradation in 5000 to 10000 cycles than earlier work with a Slow Cycle Apparatus (SCA) produced in 1500 cycles. Evidence is presented that the 453 K (356 F) Thermal Aging (TA) time spent in the saturated condition causes hydride degradation. But increasing the cooling (saturation) period in the RCA did not greatly increase the rate of degradation. It appears that TA type degradation is secondary at low temperatures to another degradation mechanism. If rapid cycles are less damaging than slow cycles when the saturation time is equal, the rate of hydriding/dehydriding may be an important factor. The peak temperatures in the RCA were about 30 C lower than the SCA. The difference in peak cycle temperatures (125 C in the SCA, 95 C in RCA) cannot explain the differences in degradation. TA type degradation is similar to cyclic degradation in that nickel peaks and line broadening are observed in X ray diffraction patterns after either form of degradation.

  13. Evaluation of Long Term Performance of Continuously Running Atomic Fountains

    CERN Document Server

    Peil, Steven; Swanson, Thomas B; Taylor, Jennifer; Ekstrom, Christopher R

    2014-01-01

    An ensemble of rubidium atomic fountain clocks has been put into operation at the U.S. Naval Observatory (USNO). These fountains are used as continuous clocks in the manner of commercial cesium beams and hydrogen masers for the purpose of improved timing applications. Four fountains have been in operation for more than two years and are included in the ensemble used to generate the USNO master clock. Individual fountain performance is characterized by a white-frequency noise level below $2\\times 10^{-13}$ and fractional-frequency stability routinely reaching the low $10^{-16}$s. The highest performing pair of fountains exhibits stability consistent with each fountain integrating as white frequency noise, with Allan deviation surpassing $6\\times 10^{-17}$ at $10^7$~s, and with no relative drift between the fountains at the level of $7.5 \\times 10^{-19}$/day. As an ensemble, the fountains generate a timescale with white-frequency noise level of $1\\times 10^{-13}$ and long-term frequency stability consistent wit...

  14. LONG-TERM OUTCOMES OF FENESTRATED DISCECTOMY FOR LUMBAR DISC

    Institute of Scientific and Technical Information of China (English)

    PAN Yu-tao; CAO Peng; LIANG Yu; GONG Yao-cheng; ZHENG Tao; ZHANG Xing-kai; WU Wen-jian

    2008-01-01

    Objective To evaluate the long-term outcomes of fenestrated discectomy for lumbar disc herniation and analyze the correlative influence factors.Methods Eighty-two cases of lumbar disc herniation, from February 1996 to May 1999, were retrospectively studied. All patients were treated with simple fenestrated discectomy. The average follow-up time was 8 years and 7 months (from 7 years to10 years and 3months). There were 13, 38 and 31 cases at L3-L4, L4-L5 and L5-S1 level, respectively.Results The average scales before operation were as following: Japanes Orthopaedics Association (JOA) scale 6.5 (5-9), visual analysis scale (VAS) of low back pain 4.8 (0-8), and VAS of sciatica 7.2 (4-10). At the final follow-up, the above parameters were 13.2 (10-14), 1.8 (0-10) and 1.2 (0-7), respectively. The average increase ratio of JOA scale was 78.8%. The average disc-vertebra height ratio (Mochida method) was 80.2%. At the final follow-up, 7 cases reoccurred disc herniation. The final clinical satisfaction rate was 80% (modified Macnab method).Conclusion With appropriate surgical indications, the successful long-term outcomes could be expected with fenestrated discectomy. Discectomy improves sciatica to a greater extent than low back pain. The occurrence of low back pain is related to intervertebral disc height, segment stability, disc degeneration, and lumbar muscle disability.

  15. Short and long-term strength of shale rocks

    Science.gov (United States)

    Rybacki, Erik; Dresen, Georg

    2016-04-01

    Stimulation of oil and gas bearing shales commonly utilizes advanced hydraulic fracturing techniques to enhance the production rate. Successful hydrofrac campaigns depend on the geomechanical properties of the reservoir. For example, the short term strength and brittleness may control the hydraulic breakdown pressure and borehole stability. The long term creep properties may determine the closure rate of hydraulically induced fractures, for example by proppant embedment. We performed a series of mechanical tests on shales with different mineral content, porosity and maturity. Cylindrical samples of 1-5 cm in diameter and 2-10 cm in length were deformed at confining pressures of 0.1 - 400 MPa and temperatures of 25°-400°C in constant strain rate and constant stress mode in order to evaluate the influence of loading conditions and composition on their strength and ductility. Short-term constant strain rate tests show that, at fixed loading direction with respect to bedding orientation, the peak strength and Young's modulus vary with mineral content, humidity and porosity, but depend also on applied pressure, temperature and strain rate. The (porosity-corrected) variation of peak strength and Young's modulus with composition can be roughly estimated from the mechanical behavior of all components at given pressure-temperature conditions and their volumetric proportion. Samples deforming in the brittle-semibrittle regime may be characterized by empirical brittleness indices based on their deformation behavior, Young's modulus, or bulk composition. These indices are correlated at low pressure-temperature conditions (corresponding to long-term deformation experiments at constant load show transient viscoplastic creep behavior. The associated strain rates increase with increasing differential stress, increasing temperature and decreasing pressure, accompanied by slight porosity reduction. Therefore, estimates of fracture healing rates by proppant embedment require to

  16. Electrocatalytic Activity and Stability of M-Fe Catalysts Synthesized by Polymer Complex Method for PEFC Cathode

    KAUST Repository

    Ou, Yiwei

    2011-11-01

    The polymerized complex (PC) method was used to synthesize highly dispersed iron-based catalysts for the oxygen reduction reaction (ORR). The catalysts were prepared with an addition of 1,10-phenanthroline (Phen) and transition metals (M), such as Ta, Ti, and W, in an attempt to enhance the ORR activity and durability of the catalysts. The composition and properties of the catalysts were characterized by thermogravimetric analysis, X-ray diffraction, and X-ray photoelectron spectroscopy. The catalyst components, after extensive dissolution in a strong acid solution, were characterized by inductively coupled plasma mass spectroscopy and ultraviolet-visible spectroscopy. It was found that the Ti-Fe catalyst showed improved ORR performance, and the Ta-Fe catalyst showed enhanced stability towards ORR in acidic solution. The catalytic activity and stability for ORR was observed by adding Ti or Ta into the catalyst formulation, suggesting that the interaction between added hetero-ions (Ti and Ta) and ionic Fe active sites was beneficial for the ORR. A single-cell test with the synthesized catalyst in the cathode initially generated a high power density, but the low stability remains an issue to be solved.

  17. Long term behaviour of singularly perturbed parabolic degenerated equation

    CERN Document Server

    Faye, Ibrahima; Seck, Diaraf

    2011-01-01

    In this paper we consider models for short-term, mean-term and long-term morphodynamics of dunes and megariples. We give an existence and uniqueness result for long term dynamics of dunes. This result is based on a time-space periodic solution existence result for degenerated parabolic equation that we set out. Finally the mean-term and long-term models are homogenized.

  18. CHARACTERISTICS OF LONG-TERM UNEMPLOYMENT SPELLS IN ROMANIA

    Directory of Open Access Journals (Sweden)

    Daniela-Emanuela Dănăcică

    2012-12-01

    Full Text Available The aim of this paper is to analyze characteristics of long-term unemployment spells in Romania and to estimate the effect of factors influencing long-term unemployment spells. The study period is in between January 1st 2008 and December 31st 2010. 468159 long-term spells registered in the specified period at the National Agency of Employment are analyzed.

  19. Quantification of long term emission potential from landfills

    OpenAIRE

    Heimovaara, T.J.

    2011-01-01

    Novel approaches for the after-care of Municipal Solid Waste (MSW) landfills are based on technological measures to reduce the long term emission potential in a short time period. Biological degradation in landfills is a means to significantly reduce the long term emission potential. Leachate emission to the groundwater is considered to be one of the largest long-term impacts related to landfilling. Currently we are starting up a research program, partly subsidized by the Dutch Technology fou...

  20. Long term behaviour of singularly perturbed parabolic degenerated equation

    Directory of Open Access Journals (Sweden)

    Ibrahima Faye

    2016-12-01

    Full Text Available In this paper we consider models built in [4] for short-term, mean-term and long-term morphodynamics of dunes and megariples. We give an existence and uniqueness result for long term dynamics of dunes. This result is based on a periodic-in-time-and-space solution existence result for degenerated parabolic equation that we set out. Finally the mean-term and long-term models are homogenized.

  1. Chromium poisoning in (La,Sr)MnO3 cathode: Three-dimensional simulation of a solid oxide fuel cell

    Science.gov (United States)

    Miyoshi, Kota; Iwai, Hiroshi; Kishimoto, Masashi; Saito, Motohiro; Yoshida, Hideo

    2016-09-01

    A three-dimensional numerical model of a single solid oxide fuel cell (SOFC) considering chromium poisoning on the cathode side has been developed to investigate the evolution of the SOFC performance over long-term operation. The degradation model applied in the simulation describes the loss of the cathode electrochemical activity as a decrease in the active triple-phase boundary (TPB) length. The calculations are conducted for two types of cell: lanthanum strontium manganite (LSM)/yttria-stabilized zirconia (YSZ)/Ni-YSZ and LSM-YSZ/YSZ/Ni-YSZ. Their electrode microstructures are acquired by imaging with a focused ion beam scanning-electron microscope (FIB-SEM). The simulation results qualitatively reproduce the trends of chromium poisoning reported in the literature. It has been revealed that the performance degradation by chromium is primarily due to an increase in the cathode activation overpotential. In addition, in the LSM-YSZ composite cathode, TPBs in the vicinity of the cathode-electrolyte interface preferentially deteriorate, shifting the active reaction site towards the cathode surface. This also results in an increase in the cathode ohmic loss associated with oxide ion conduction through the YSZ phase. The effects of the cell temperature, the partial pressure of steam at the chromium source, the cathode microstructure, and the cathode thickness on chromium poisoning are also discussed.

  2. Consider long-term care as service alternative.

    Science.gov (United States)

    Loria, L S

    1987-04-01

    The increasing demand for elderly care services, pressures on inpatient average length of stay and payment levels, and potential financial rewards from providing additional services, makes long-term care look attractive to hospitals. Long-term care, however, is not for every hospital. Before deciding to establish long-term care services, management should examine how the service fits within the hospital's strategic plan. The action plan below provides guidance in evaluating a decision to use hospital facilities for long-term care. Examine how long-term care services fit within the hospital's strategic plan. Study area demographics and competitors to assess the need and supply of long-term care services. Survey the medical staff, consumers and payers to determine attitudes, perceptions and interests regarding long-term care services. Develop a facility plan that identifies areas of excess capacity that can be most easily converted into long-term care with minimal effects on hospital operations. Prepare a financial feasibility analysis of the contribution margin and return on investment attributable to long-term care services. Include an impact analysis on hospital operations. Establish a management task force to develop a detailed implementation plan including assigned individual responsibilities and related timetable. Develop an effective marketing plan designed to generate increased patient market share.

  3. Long term characterization of voltage references

    CERN Document Server

    Halloin, Hubert; Brossard, Julien

    2013-01-01

    We report here the characterization (temperature coefficients and noise level) of selected voltage references in the frequency range from 10^(-5) to 10 Hz. The goal of this work is to update previous studies, with a characterization at lower frequencies, and find voltage references that may be suitable for the space-based interferometry mission eLISA. The requirements of relative output stability of 1 ppm/$\\sqrt{\\text{Hz}}$ down to 0.1 mHz were not met by any of the tested devices, but 4 references approaches the objective : the AD587UQ, the MAX6126AASA50, the LT1021-BCN8-5 and the LT6655BHM. While the first three were already identified as potential devices in previous studies, the later is a new promising candidate using a different technology (bandgap).

  4. The long-term effect of the timing of fertility decline on population size

    NARCIS (Netherlands)

    O'Neill, BC; Scherbov, S; Lutz, W

    1999-01-01

    Existing long-range population projections imply that the timing of the fertility transition has a relatively unimportant effect on long-term population size when compared with the impact of the level at which fertility is assumed eventually to stabilize. However, this note shows that the effect of

  5. Nanoporous silver cathode surface treated by atomic layer deposition of CeO(x) for low-temperature solid oxide fuel cells.

    Science.gov (United States)

    Neoh, Ke Chean; Han, Gwon Deok; Kim, Manjin; Kim, Jun Woo; Choi, Hyung Jong; Park, Suk Won; Shim, Joon Hyung

    2016-05-06

    We evaluated the performance of solid oxide fuel cells (SOFCs) with a 50 nm thin silver (Ag) cathode surface treated with cerium oxide (CeO(x)) by atomic layer deposition (ALD). The performances of bare and ALD-treated Ag cathodes were evaluated on gadolinia-doped ceria (GDC) electrolyte supporting cells with a platinum (Pt) anode over 300 °C-450 °C. Our work confirms that ALD CeO(x) treatment enhances cathodic performance and thermal stability of the Ag cathode. The performance difference between cells using a Ag cathode optimally treated with an ALD CeO(x) surface and a reference Pt cathode is about 50% at 450 °C in terms of fuel cell power output in our experiment. The bare Ag cathode completely agglomerated into islands during fuel cell operation at 450 °C, while the ALD CeO(x) treatment effectively protects the porosity of the cathode. We also discuss the long-term stability of ALD CeO(x)-treated Ag cathodes related to the microstructure of the layers.

  6. The Effect of Modality on Long-Term Recognition Memory.

    Science.gov (United States)

    Dean, Raymond S.; And Others

    1988-01-01

    The effects of visual and auditory modes of input on long-term memory were examined in two experiments, each with 40 and 80 undergraduates, respectively. In both experiments, visual stimulus attributes were a more salient dimension than were auditory features in the long-term encoding and retrieval process. (SLD)

  7. Factors associated with long-term mortality in acute pancreatitis

    DEFF Research Database (Denmark)

    Nøjgaard, Camilla; Matzen, Peter; Bendtsen, Flemming

    2011-01-01

    Knowledge of the long-term prognosis of acute pancreatitis (AP) is limited. The aims were to investigate: (1) prognostic factors associated with long-term mortality in patients with AP; (2) whether or not the level of serum (S-)amylase at admission had an impact on the prognosis; (3) causes...

  8. Determinants and consequences of long-term benzodiazepine use

    NARCIS (Netherlands)

    Manthey, Leonie

    2012-01-01

    The main objective of this thesis is to describe the epidemiology of long term BZD use as well as its long term consequences. This thesis is structured into three sections: In section one, the correlates of BZD use, new use, chronic use, inappropriate use, and BZD dependence severity are investigate

  9. Pediatric polytrauma : Short-term and long-term outcomes

    NARCIS (Netherlands)

    vanderSluis, CK; Kingma, J; Eisma, WH; tenDuis, HJ

    1997-01-01

    Objective: To assess the short-term and long-term outcomes of pediatric polytrauma patients and to analyze the extent to which short-term outcomes can predict long-term outcomes. Materials and Methods: Ail pediatric polytrauma patients (Injury Severity Score of greater than or equal to 16, less than

  10. Standards for Psychological Services in Long-Term Care Facilities.

    Science.gov (United States)

    Morrow-Howell, Nancy; Lichtenberg, Peter A.; Smith, Michael; Frazer, Deborah; Molinari, Victor; Rosowsky, Erlene; Crose, Royda; Stillwell, Nick; Kramer, Nanette; Hartman-Stein, Paula; Qualls, Sara; Salamon, Michael; Duffy, Michael; Parr, Joyce; Gallagher-Thompson, Dolores

    1998-01-01

    Describes the development of standards for psychological practice in long-term care facilities. The standards, which were developed by Psychologists in Long-Term Care, address provider characteristics, methods of referral, assessment practices, treatment, and ethical issues. Offers suggestions for use of the standards. (MKA)

  11. IPO-related organizational change and long-term performance

    NARCIS (Netherlands)

    Eije, J.H. von; Witte, M.C. de; Zwaan, A.H. van der

    2000-01-01

    Mainstream literature on long-term performance of initial public offerings focuses on long-term underperformance. Because underperformance is an anomalous phenomenon, many authors search for explanations based on financial market imperfections. More recently, however, the attention shifts from under

  12. Psychological symptoms as long-term consequences of war experiences

    NARCIS (Netherlands)

    S. Priebe; J. Jankovic Gavrilovic; S. Bremner; D. Ajdukovic; T. Franciskovic; G.M. Galeazzi; A. Kucukalic; D. Lecic-Tosevski; N. Morina; M. Popovski; M. Schützwohl; M. Bogic

    2012-01-01

    Background/Aims: War experiences can affect mental health, but large-scale studies on the long-term impact are rare. We aimed to assess long-term mental health consequences of war in both people who stayed in the conflict area and refugees. Method: On average 8 years after the war in former Yugoslav

  13. Bacteremia is associated with excess long-term mortality

    DEFF Research Database (Denmark)

    Nielsen, Stig Lønberg; Lassen, Annmarie Touborg; Gradel, Kim Oren;

    2015-01-01

    OBJECTIVES: Little is known about long-term outcomes following bacteremia. We investigated long-term mortality and causes of death among bacteremia patients compared with population controls. METHODS: Population-based cohort study of bacteremia patients and population controls matched on sex, yea...

  14. Long Term Incentives for Residential Customers Using Dynamic Tariff

    DEFF Research Database (Denmark)

    Huang, Shaojun; Wu, Qiuwei; Nielsen, Arne Hejde;

    2015-01-01

    This paper reviews several grid tariff schemes, including flat tariff, time-of-use, time-varying tariff, demand charge and dynamic tariff (DT), from the perspective of the long term incentives. The long term incentives can motivate the owners of flexible demands to change their energy consumption...

  15. Quantification of long term emission potential from landfills

    NARCIS (Netherlands)

    Heimovaara, T.J.

    2011-01-01

    Novel approaches for the after-care of Municipal Solid Waste (MSW) landfills are based on technological measures to reduce the long term emission potential in a short time period. Biological degradation in landfills is a means to significantly reduce the long term emission potential. Leachate emissi

  16. [Developing the core competencies of long-term care professionals].

    Science.gov (United States)

    Chen, Huey-Tzy; Lee, Kuang-Ting

    2012-12-01

    Longer average life expectancies and an ageing society have made long-term care an urgent and important issue in Taiwan. Although the implementation of Long-Term Care Ten-year Project four years ago has begun showing success in terms of assessing Taiwan's needs in terms of long-term care services and resources, there has been little forward progress in terms of training, recruiting and maintaining more competent professionals in the long-term care sector. This paper explores the current state of long-term care competency in Taiwan and educational strategies in place to improve the competency of long-term care professionals. Results indicate that the term geriatric competency embraces sub-competencies in direct care, communication, assessment, teamwork, cultural sensitivities and career care competencies. The term long-term care competency embraces the sub-competencies of supervision, management, information technology, resource management, and organizational skill. As a main contributor to effective long-term care, the nursing profession must employ effective strategies to develop competency-based education. Also, the profession must have an adequate supply of competent manpower to effectively respond to Taiwan's aging society.

  17. Long-term effects of a preoperative smoking cessation programme

    DEFF Research Database (Denmark)

    Villebro, Nete Munk; Pedersen, Tom; Møller, Ann M;

    2008-01-01

    Preoperative smoking intervention programmes reduce post-operative complications in smokers. Little is known about the long-term effect upon smoking cessation.......Preoperative smoking intervention programmes reduce post-operative complications in smokers. Little is known about the long-term effect upon smoking cessation....

  18. A new image for long-term care.

    Science.gov (United States)

    Wager, Richard; Creelman, William

    2004-04-01

    To counter widely held negative images of long-term care, managers in the industry should implement quality-improvement initiatives that include six key strategies: Manage the expectations of residents and their families. Address customers' concerns early. Build long-term customer satisfaction. Allocate resources to achieve exceptional outcomes in key areas. Respond to adverse events with compassion. Reinforce the facility's credibility.

  19. A perspective on coatings to stabilize high-voltage cathodes: LiMn1.5Ni0.5O4 with subnanometer Lipon cycled with LiPF6 electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yoongu [ORNL; Dudney, Nancy J [ORNL; Chi, Miaofang [ORNL; Martha, Surendra K [ORNL; Nanda, Jagjit [ORNL; Veith, Gabriel M [ORNL; Liang, Chengdu [ORNL

    2013-01-01

    High voltage Li-ion cathodes push the limits of stability for both cathode and electrolyte. Here subnanometer coatings of an amorphous thin film electrolyte (Lipon) improved the room temperature and 60 C cycling stability of a LiMn1.5Ni0.5O4 spinel cathode when charged to 4.9V with a standard LiPF6 carbonate electrolyte. The cathodes delivered superior C-rate performances up to a 5C discharge, when compared to the uncoated cathodes. Enhanced performance extended for at least 100 cycles. Electrochemical impedance spectroscopy indicates that Lipon slows the increase of interface resistance. Thicker 1-3nm Lipon coatings are sufficiently insulating as to block electronic transport to the cathode particles. Thick coatings also slow Mn dissolution. Results suggest that Lipon may act to scavenge impurities or block active sites that promote electrolyte decomposition. While greatly improved by the Lipon coating, this cathode is not sufficiently stable for long cycle life applications. Further work is needed to assess if and what surface coatings will ultimately stabilize the high voltage cathodes. Comments include insight from other studies of Lipon coated cathodes and directions for future research.

  20. 棘突间动态稳定装置Wallis治疗腰椎退行性疾病中长期随访效果分析%Intermediate and long-term follow-up evaluation of posterior dynamic lumbar stabilization in lumbar degenerative disease

    Institute of Scientific and Technical Information of China (English)

    徐林; 俞兴; 毕连涌; 柳根哲; 李鹏洋; 曲弋; 焦勇

    2012-01-01

    目的 探讨棘突间动态稳定装置Wallis治疗腰椎退行性疾病的中长期效果.方法 回顾性分析2007年8月至2010年1月采用Wallis或结合固定融合方法治疗腰椎退行性疾病并有2年以上随访的96例患者资料,其中男性51例,女性45例;年龄21 ~ 68岁,平均41.5岁.采用疼痛视觉模拟量表(VAS)1 00分法和中华医学会骨科分会脊柱外科学组腰椎手术疗效标准评估手术短期和中长期疗效,测量分析术前、术后3个月和末次随访时Wallis植入节段椎间盘终板高度,随访有无Wallis相关并发症及患者对手术的满意度,部分患者MRI检查分析Wallis植入节段术后椎间盘影像学变化.结果 术前、术后3个月及末次随访疼痛VAS评分分别为78 ±24、28±16和14±12,采用配对t检验,术后3个月及末次随访疼痛VAS评分较术前明显下降(t=2.634和2.653,P<0.01);末次随访疼痛VAS评分较术后3个月也有下降(t=2.147,P<0.05).术后末次随访功能恢复优良率为91.7%,患者手术整体满意率为95.8%,术前、术后3个月和末次随访时Wallis植入节段椎间盘终板高度分别为(8.2±3.7)、(10.4±2.6)和(10.1±1.9) mm,MRI检查未发现植入节段间盘退变加速、部分患者可见椎间盘水化.结论 棘突间动态稳定装置Wallis或结合固定融合方法治疗腰椎退行性疾病简便安全,2年以上中长期随访疗效良好,为腰椎退行性疾病的手术治疗增加了一种新的选择.%Objective To evaluate the intermediate and long-term follow-up effect of posterior dynamic lumbar stabilization in lumbar degenerative disease.Methods The clinical outcomes of 96 patients (male 51,female 45,age from 21 to 68 years,mean 41.5 years) whose follow-up time were more than 2 years with lumbar degenerative disease treated by posterior decompression with Wallis posterior dynamic lumbar stabilization implant or combined with posterior lumbar fusion from August 2007 to January 2010 were

  1. Synaptic scaling enables dynamically distinct short- and long-term memory formation.

    Directory of Open Access Journals (Sweden)

    Christian Tetzlaff

    2013-10-01

    Full Text Available Memory storage in the brain relies on mechanisms acting on time scales from minutes, for long-term synaptic potentiation, to days, for memory consolidation. During such processes, neural circuits distinguish synapses relevant for forming a long-term storage, which are consolidated, from synapses of short-term storage, which fade. How time scale integration and synaptic differentiation is simultaneously achieved remains unclear. Here we show that synaptic scaling - a slow process usually associated with the maintenance of activity homeostasis - combined with synaptic plasticity may simultaneously achieve both, thereby providing a natural separation of short- from long-term storage. The interaction between plasticity and scaling provides also an explanation for an established paradox where memory consolidation critically depends on the exact order of learning and recall. These results indicate that scaling may be fundamental for stabilizing memories, providing a dynamic link between early and late memory formation processes.

  2. Long-term stable microwave signal extraction from mode-locked lasers

    Science.gov (United States)

    Kim, J.; Ludwig, F.; Felber, M.; Kärtner, F. X.

    2007-07-01

    Long-term synchronization between two 10.225 GHz microwave signals at +10 dBm power level, locked to a 44.26 MHz repetition rate passively mode-locked fiber laser, is demonstrated using balanced optical-microwave phase detectors. The out-of-loop measurement result shows 12.8 fs relative timing jitter integrated from 10 Hz to 10 MHz. Long-term timing drift measurement shows 48 fs maximum deviation over one hour, mainly limited by drift of the out-of-loop characterization setup itself. To the best of our knowledge, this is the first time to demonstrate long-term (>1 hour) 3 mrad-level phase stability of a 10.225 GHz microwave signal extracted from a mode-locked laser.

  3. Benefits from Long-Term Treatment in Irritable Bowel Syndrome

    Directory of Open Access Journals (Sweden)

    Stefano Evangelista

    2012-01-01

    Full Text Available It is known that irritable bowel syndrome (IBS is a chronic disease of cyclic nature characterized by recurrent symptoms. IBS patients should receive, as initial therapeutic approach a short course of treatment which, if effective, has the additional value of confirming the diagnosis. Long-term treatment should be reserved to diagnosed IBS patients with recurrent symptoms. Clinical trials with stabilized therapies and new active treatments showed an improvement of the symptoms over placebo that is often time-dependent but with high relapse rates (around 40%–50% when stopping treatment. Relapse is not always immediate after stopping treatment and the recent data from OBIS trial with otilonium bromide or with psychotherapy, showed that due to different chemico-physical characteristics of the drugs or the psychosomatic impact to the disease not all treatment gave the same relapsing rate if compared to placebo. Results of IBS clinical trials with different therapies tailored to the patient needs indicate that a cyclic treatment therapy is advisable to counteract the nature of the disease.

  4. Long-term forecast: key to groundwater protection.

    Science.gov (United States)

    Gerth, Joachim; Förstner, Ulrich

    2004-01-01

    Groundwater resources are at risk from pollution, climate change and land-management practices. Long-term forecast is a tool to demonstrate future development and to support decisions on measures which can be implemented, controlled and eventually corrected. As the basis for preventive action, a forecast can be viewed as a key to groundwater protection. The soil zone plays a vital role in groundwater protection. Research on soil and groundwater trends, as affected by change of climate and/or land-management practices, is on the agenda. Integrated research is necessary to develop numerical soil-water system models reflecting all relevant transport processes at various scales. Even relatively simple problems like forecasting pollutant release from contaminated materials are difficult to resolve. Batch tests may be sufficient in low-risk cases. At higher risk when contaminated substrates are chosen for deposition on a large scale, a thorough characterization of the materials is necessary covering all aspects of stability and possible changes of the environment.

  5. Long-term corrosion of rebars embedded in aerial and hydraulic binders - Parametric study and first step of modelling

    Energy Technology Data Exchange (ETDEWEB)

    Chitty, Walter-John [CEA, DSM, IRAMIS, Laboratoire Pierre Suee, F-91191 Gif-sur-Yvette cedex (France); Dillmann, Philippe [CEA, DSM, IRAMIS, Laboratoire Pierre Suee, F-91191 Gif-sur-Yvette cedex (France); Institut de Recherches sur les Archeomateriaux, LMC UMR5060 CNRS (France)], E-mail: philippe.dillmann@cea.fr; L' Hostis, Valerie [CEA, DEN, DPC, SCCME, Laboratoire d' Etude du Comportement des Betons et des Argiles, F-91191 Gif-sur-Yvette (France); Millard, Alain [CEA, DEN, DM2S, SEMT, Laboratoire de Modelisation, Systemes et Simulation, F-91191 Gif-sur-Yvette (France)

    2008-11-15

    The prediction of long-term behaviour of reinforced concrete structures involved in the nuclear industry requires a phenomenological modelling of the rebars corrosion processes. Previous analytical characterisation of archaeological artefacts allowed to identify a typical layout constituted of four layers (the metal, the dense product layer, the transformed medium and the binder). Additional experiments leaded to identify the long-term corrosion mechanisms. Following these results, this paper proposes an analytical model of long-term corrosion of rebars embedded in concrete. This modelling is considering the kinetic of oxygen diffusion through the system and its consumption at the metal/dense product layer interface as a function of concrete water saturation degree. Corrosion products thicknesses estimated with the model are then compared to corrosion product thicknesses measured on archaeological artefacts. A parametric study is performed and demonstrates that the oxygen diffusivity and the kinetic constant of the cathodic reaction affect in a wide range the model results.

  6. A Long-Term View on Perovskite Optoelectronics.

    Science.gov (United States)

    Docampo, Pablo; Bein, Thomas

    2016-02-16

    Recently, metal halide perovskite materials have become an exciting topic of research for scientists of a wide variety of backgrounds. Perovskites have found application in many fields, starting from photovoltaics and now also making an impact in light-emitting applications. This new class of materials has proven so interesting since it can be easily solution processed while exhibiting materials properties approaching the best inorganic optoelectronic materials such as GaAs and Si. In photovoltaics, in only 3 years, efficiencies have rapidly increased from an initial value of 3.8% to over 20% in recent reports for the commonly employed methylammonium lead iodide (MAPI) perovskite. The first light emitting diodes and light-emitting electrochemical cells have been developed already exhibiting internal quantum efficiencies exceeding 15% for the former and tunable light emission spectra. Despite their processing advantages, perovskite optoelectronic materials suffer from several drawbacks that need to be overcome before the technology becomes industrially relevant and hence achieve long-term application. Chief among these are the sensitivity of the structure toward moisture and crystal phase transitions in the device operation regime, unreliable device performance dictated by the operation history of the device, that is, hysteresis, the inherent toxicity of the structure, and the high cost of the employed charge selective contacts. In this Account, we highlight recent advances toward the long-term viability of perovskite photovoltaics. We identify material decomposition routes and suggest strategies to prevent damage to the structure. In particular, we focus on the effect of moisture upon the structure and stabilization of the material to avoid phase transitions in the solar cell operating range. Furthermore, we show strategies to achieve low-cost chemistries for the development of hole transporters for perovskite solar cells, necessary to be able to compete with other

  7. The long term stability of skeletal class III malocclusion after orthodontic-surgery:A meta-analysis%正畸正颌联合矫治骨性 III 类错牙合软硬组织稳定性的 Meta 分析

    Institute of Scientific and Technical Information of China (English)

    白洋; 邓梦旋; 袁小平

    2015-01-01

    目的:采用 Meta 分析方法评价正畸正颌联合矫治骨性 III 类错�软硬组织的稳定性。方法:计算机检索 Cochrane Library、PubMed、Medline、CNKI、万方等中外文数据库中符合要求的随机对照试验、半随机对照试验、临床病例对照试验的文献,检索日期截止2013-12-31。按照纳入、排除标准,由2名经过系统评价专业培训的研究者对纳入文献进行严格的质量评价,提取中、高等质量文献的数据资料。然后采用 RevMan 5.2软件进行 Meta 分析。结果:最终纳入4篇文献,共178例患者,均为临床病例对照试验(CCT)。Meta 分析结果示:硬组织稳定性:SNA(WMD =-0.58,95%CI[-1.18,0.02])、SNB (WMD =0.25,95%CI[-0.42,0.91])、ANB(WMD =-0.70,95%CI[-1.44,0.04])、MP-SN(WMD =0.39,95%CI [-0.25,1.04]),术后与术后3年差异无统计学意义,A 点保持相对稳定位置,B 点较术后有复发;软组织稳定性:术后与术后3年患者的软组织总体上保持稳定,仅下唇突度术后3年有所增大,显示其有一定的复发。结论:骨性 III 类错�患者经正畸联合双颌手术治疗后,软硬组织基本保持了长期的稳定性,仅下颌有一定的向前复发,下唇突度有所增大。%Objective:To analyze the long term stability of the hard and soft tissues of the skeletal class III malocclusion after ortho-dontic-surgery by Meta-analysis.Methods:The randomized controlled trials(RCT),quasi-randomized controlled trials and clinical case-control trials(CCT)about the long-term stability of skeletal class III malocclusion after orthodontic-surgery was collected from Co-chrane Library,PubMed,Medline,CNKI,VIP and Wanfang databases from inception to December 31,2013 by literature search.Two professionally trained reviewers evaluated the quality of the screened literatures,scored literatures with the NOS

  8. Inhibition of microbial growth on air cathodes of single chamber microbial fuel cells by incorporating enrofloxacin into the catalyst layer.

    Science.gov (United States)

    Liu, Weifeng; Cheng, Shaoan; Sun, Dan; Huang, Haobin; Chen, Jie; Cen, Kefa

    2015-10-15

    The inevitable growth of aerobic bacteria on the surface of air cathodes is an important factor reducing the performance stability of air cathode single-chamber membrane-free microbial fuel cells (MFCs). Thus searching for effective methods to inhibit the cathodic microbial growth is critical for the practical application of MFCs. In this study, enrofloxacin (ENR), a broad spectrum fluoroquinolone antibiotic, was incorporated into the catalyst layer of activated carbon air cathodes (ACACs) to inhibit the cathodic microbial growth. The biomass content on ACACs was substantially reduced by 60.2% with ENR treatment after 91 days of MFCs operation. As a result of the inhibited microbial growth, the oxygen reduction catalytic performance of the ENR treated ACACs was much stable compared to the fast performance decline of the untreated control. Consequently, a quite stable electricity production was obtained for the MFCs with the ENR treated ACACs, in contrast with a 22.5% decrease in maximum power density of the MFCs with the untreated cathode. ENR treatment of ACACs showed minimal effects on the anode performance. These results indicate that incorporating antibiotics into ACACs should be a simple and effective strategy to inhibit the microbial growth and improve the long-term stability of the performance of air cathode and the electricity production of MFCs.

  9. Sulfur loaded in micropore-rich carbon aerogel as cathode of lithium-sulfur battery with improved cyclic stability

    Science.gov (United States)

    Li, Zihao; Li, Xiaogang; Liao, Youhao; Li, Xiaoping; Li, Weishan

    2016-12-01

    We report a novel composite of sulfur loaded in micropore-rich carbon aerogel (CA-S), as cathode of lithium-sulfur battery. Carbon aerogel (CA) is synthesized through phenol-formaldehyde reaction with a low catalyst concentration and carbonization under high temperature, and loaded with sulfur via chemical deposition and heat treatment. The physical properties of the resulting CA and the electrochemical performances of the resulting CA-S are investigated by scanning electron microscopy, thermal gravimetric analysis, Brunauer-Emmett-Teller characterization, electrochemical impedance spectroscopy, and galvanostatic discharge/charge test, with a comparison of a common carbon material, acetylene black (AB), and sulfur loaded in AB (AB-S). It is found that the CA is micropore-rich with micropore volume over 66% of total pore volume, and the CA-S exhibits significantly improved cyclic stability compared with AB-S. The improved performance of CA-S is attributed to the confinement of the micropores in CA to small sulfur allotropes and corresponding lithium sulfides.

  10. Improving cyclic stability of lithium nickel manganese oxide cathode at elevated temperature by using dimethyl phenylphosphonite as electrolyte additive

    Science.gov (United States)

    Mai, Shaowei; Xu, Mengqing; Liao, Xiaolin; Xing, Lidan; Li, Weishan

    2015-01-01

    A novel electrolyte additive, dimethyl phenylphosphonite (DMPP), is reported in this paper to be able to improve significantly the cyclic stability of LiNi0.5Mn1.5O4 cathode of high voltage lithium ion battery at elevated temperature. When experiencing charge/discharge cycling at 50 °C with 1C (1C = 146.7 mAh g-1) rate in a standard (STD) electrolyte (1.0 M LiPF6 in ethylene carbonate (EC)/dimethyl carbonate (DMC), EC/DMC = 1/2 in volume), LiNi0.5Mn1.5O4 suffers serious discharge capacity decaying, with a capacity retention of 42% after 100 cycles. With adding 0.5% DMPP into the STD electrolyte, the capacity retention is increased to 91%. This improvement can be ascribed to the preferential oxidation of DMPP to the STD electrolyte and the subsequent formation of a protective film on LiNi0.5Mn1.5O4, which suppresses the electrolyte decomposition and protects LiNi0.5Mn1.5O4 from destruction. Theoretical calculations together with voltammetric analyses demonstrate the preferential oxidation of DMPP and the consequent suppression of electrolyte decomposition, while the observations from scanning electron microscopy, X-ray photoelectronic spectroscopy and Fourier transform infrared spectroscopy confirm the protection that DMPP provides for LiNi0.5Mn1.5O4.

  11. The market for long-term care services.

    Science.gov (United States)

    Grabowski, David C

    2008-01-01

    Although a large literature has established the importance of market and regulatory forces within the long-term care sector, current research in this field is limited by a series of data, measurement, and methodological issues. This paper provides a comprehensive review of these issues with an emphasis on identifying initiatives that will increase the volume and quality of long-term care research. Recommendations include: the construction of standard measures of long-term care market boundaries, the broader dissemination of market and regulatory data, the linkage of survey-based data with market measures, the encouragement of further market-based studies of noninstitutional long-term care settings, and the standardization of Medicaid cost data.

  12. Managerial Long-Term Responsibility in Family-Controlled Firms

    Directory of Open Access Journals (Sweden)

    Dietmar Sternad

    2013-01-01

    Full Text Available Evidence suggests that long-term orientation (LTO as a dominantstrategic logic contributes to the sustainable performance offamily-controlled firms (FCFS. Combining a review of the literatureon lto with stewardship theory and upper echelons theoryreasoning, this article presents a typology of managerial responsibilityand introduces the concept of long-term responsibility as amanagerial characteristic constituting a major driving force behindcreating lto. The antecedents of long-term responsibilityunder family firm-specific conditions (stemming from the familysystem, the governance system, and family-firm managers’ personalcharacteristics are also identified and presented in an integratedmodel. The paper contributes to a more comprehensiveunderstanding of intertemporal choice in fcfs and explains whythey tend to be more long-term oriented than other types of firms.

  13. Office of Disability, Aging and Long-Term Care Policy

    Science.gov (United States)

    ... Publications Data and Tools Evaluation Database Office of Disability, Aging and Long-Term Care Policy (DALTCP) Home About Offices Disability, Aging, and Long-Te... DALTCP provides leadership on ...

  14. Biogeochemistry: Long-term effects of permafrost thaw

    Science.gov (United States)

    Zona, Donatella

    2016-09-01

    Carbon emissions from the Arctic tundra could increase drastically as global warming thaws permafrost. Clues now obtained about the long-term effects of such thawing on carbon dioxide emissions highlight the need for more data.

  15. Long-term memory, sleep, and the spacing effect.

    Science.gov (United States)

    Bell, Matthew C; Kawadri, Nader; Simone, Patricia M; Wiseheart, Melody

    2014-01-01

    Many studies have shown that memory is enhanced when study sessions are spaced apart rather than massed. This spacing effect has been shown to have a lasting benefit to long-term memory when the study phase session follows the encoding session by 24 hours. Using a spacing paradigm we examined the impact of sleep and spacing gaps on long-term declarative memory for Swahili-English word pairs by including four spacing delay gaps (massed, 12 hours same-day, 12 hours overnight, and 24 hours). Results showed that a 12-hour spacing gap that includes sleep promotes long-term memory retention similar to the 24-hour gap. The findings support the importance of sleep to the long-term benefit of the spacing effect.

  16. Long-term monitoring for nanomedicine implants and drugs

    Science.gov (United States)

    Kendall, Michaela; Lynch, Iseult

    2016-03-01

    Increasing globalization means that traditional occupational epidemiological approaches may no longer apply, suggesting a need for an alternative model to assess the long-term impact of nanomaterial exposure on health.

  17. Assisted Living Facilities - MO 2010 Long Term Care Facilities (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Long Term Care facilities (nursing homes) in Missouri - Data will not be made available for download via MSDIS. Interested parties should send an email inquiry to...

  18. Long-term intrathecal administration of midazolam and clonidine

    NARCIS (Netherlands)

    Borg, PAJ; Krijnen, HJ

    1996-01-01

    Objective: To determine the clinical usefulness of the long-term intrathecal administration of midazolam and clonidine in patients with refractory neurogenic and musculoskeletal pain. Setting: Pain Centre, Academic Hospital Groningen, Groningen, The Netherlands. Patients: Four patients with chronic

  19. Long-term patient survival in ANCA-associated vasculitis

    NARCIS (Netherlands)

    Flossmann, Oliver; Berden, Annelies; de Groot, Kirsten; Hagen, Chris; Harper, Lorraine; Heijl, Caroline; Hoglund, Peter; Jayne, David; Luqmani, Raashid; Mahr, Alfred; Mukhtyar, Chetan; Pusey, Charles; Rasmussen, Niels; Stegeman, Coen; Walsh, Michael; Westman, Kerstin

    2011-01-01

    Background Wegener's granulomatosis and microscopic polyangiitis are antineutrophil cytoplasm antibodies (ANCA)-associated vasculitides with significant morbidity and mortality. The long-term survival of patients with ANCA associated vasculitis treated with current regimens is uncertain. Objective T

  20. Long-term Outcomes of Childhood Onset Nephrotic Syndrome.

    Science.gov (United States)

    Hjorten, Rebecca; Anwar, Zohra; Reidy, Kimberly Jean

    2016-01-01

    There are limited studies on long-term outcomes of childhood onset nephrotic syndrome (NS). A majority of children with NS have steroid-sensitive nephrotic syndrome (SSNS). Steroid-resistant nephrotic syndrome (SRNS) is associated with a high risk of developing end-stage renal disease. Biomarkers and analysis of genetic mutations may provide new information for prognosis in SRNS. Frequently relapsing and steroid-dependent NS is associated with long-term complications, including dyslipidemia, cataracts, osteoporosis and fractures, obesity, impaired growth, and infertility. Long-term complications of SSNS are likely to be under-recognized. There remain many gaps in our knowledge of long-term outcomes of childhood NS, and further study is indicated.

  1. Kids' Mild Brain Injury Can Have Long-Term Effects

    Science.gov (United States)

    ... Brain Injury Can Have Long-Term Effects Early head trauma linked to psychiatric, financial issues as adults, study ... HealthDay News) -- Young people who suffer even mild head trauma are more likely to have serious issues later ...

  2. Long-Term Ecological Monitoring Field Sampling Plan for 2007

    Energy Technology Data Exchange (ETDEWEB)

    T. Haney

    2007-07-31

    This field sampling plan describes the field investigations planned for the Long-Term Ecological Monitoring Project at the Idaho National Laboratory Site in 2007. This plan and the Quality Assurance Project Plan for Waste Area Groups 1, 2, 3, 4, 5, 6, 7, 10, and Removal Actions constitute the sampling and analysis plan supporting long-term ecological monitoring sampling in 2007. The data collected under this plan will become part of the long-term ecological monitoring data set that is being collected annually. The data will be used t determine the requirements for the subsequent long-term ecological monitoring. This plan guides the 2007 investigations, including sampling, quality assurance, quality control, analytical procedures, and data management. As such, this plan will help to ensure that the resulting monitoring data will be scientifically valid, defensible, and of known and acceptable quality.

  3. Sensitivity of train stochastic dynamics to long-term evolution of track irregularities

    Science.gov (United States)

    Lestoille, N.; Soize, C.; Funfschilling, C.

    2016-05-01

    The influence of the track geometry on the dynamic response of the train is of great concern for the railway companies, because they have to guarantee the safety of the train passengers in ensuring the stability of the train. In this paper, the long-term evolution of the dynamic response of the train on a stretch of the railway track is studied with respect to the long-term evolution of the track geometry. The characterisation of the long-term evolution of the train response allows the railway companies to start off maintenance operations of the track at the best moment. The study is performed using measurements of the track geometry, which are carried out very regularly by a measuring train. A stochastic model of the studied stretch of track is created in order to take into account the measurement uncertainties in the track geometry. The dynamic response of the train is simulated with a multibody software. A noise is added in output of the simulation to consider the uncertainties in the computational model of the train dynamics. Indicators on the dynamic response of the train are defined, allowing to visualize the long-term evolution of the stability and the comfort of the train, when the track geometry deteriorates.

  4. 3D printed cellular solid outperforms traditional stochastic foam in long-term mechanical response

    Science.gov (United States)

    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.

  5. Long-term mortality after Staphylococcus aureus spondylodiscitis

    DEFF Research Database (Denmark)

    Aagaard, Theis; Larsen, Anders R; Roed-Petersen, Casper;

    2014-01-01

    Patients diagnosed with Staphylococcus aureus spondylodiscitis have increased long-term mortality compared with the background population mainly due to infectious, endocrine, cardiovascular, gastrointestinal and alcohol and drug abuse-related diseases.......Patients diagnosed with Staphylococcus aureus spondylodiscitis have increased long-term mortality compared with the background population mainly due to infectious, endocrine, cardiovascular, gastrointestinal and alcohol and drug abuse-related diseases....

  6. Comparison of Long-term World Energy Studies

    OpenAIRE

    Schade, Burkhard; WIESENTHAL TOBIAS

    2007-01-01

    The POLES (Prospective Outlook for the Long-term Energy System) model is a global sectoral simulation model for the development of long-term energy supply and demand scenarios until 2050. The model is used to calculate global energy scenarios, such as the World Energy, Technology and Climate Policy Outlook (WETO) and the WETO-H2 update. In addition, dedicated greenhouse gas emission reduction scenarios are increasingly produced to support the assessment of climate change policies and measures...

  7. Cyclical Long-term Unemployment, Skill Loss, and Monetary Policy

    OpenAIRE

    2012-01-01

    Movements in long-term unemployment (LTU) exhibit a substantial cyclical component. I develop a business cycle model featuring labor market frictions and skill loss during unemployment to capture various stylized facts about the cyclical behavior of long-term unemployment. I find that the skill loss mechanism helps reproduce negative duration dependence, high persistence in unemployment and output, volatility patterns across macroeconomic variables and the behavior of the incidence of LTU aro...

  8. Long-term plasticity in interneurons of the dentate gyrus

    OpenAIRE

    Ross, Stephen T.; Soltesz, Ivan

    2001-01-01

    Single interneurons influence thousands of postsynaptic principal cells, and the control of interneuronal excitability is an important regulator of the computational properties of the hippocampus. However, the mechanisms underlying long-term alterations in the input–output functions of interneurons are not fully understood. We report a mechanism of interneuronal plasticity that leads to the functional enhancement of the gain of glutamatergic inputs in the absence of long-term potentiation of ...

  9. Long-term care: a substantive factor in financial planning.

    Science.gov (United States)

    Willis, D A

    2000-01-01

    More than 50 percent of women will enter a nursing home at some point in their lives. About one-third of men living to age 65 will also need nursing home care. Planning for long-term care is even more important since Medicare covers very little of the cost of such care. The Indiana Partnership Plan is one program designed to help fund the long-term care costs while allowing individuals protect other financial assets.

  10. Long-term Outcomes of Childhood Onset Nephrotic Syndrome

    OpenAIRE

    Hjorten, Rebecca; Anwar, Zohra; Reidy, Kimberly Jean

    2016-01-01

    There are limited studies on long-term outcomes of childhood onset nephrotic syndrome (NS). A majority of children with NS have steroid-sensitive nephrotic syndrome (SSNS). Steroid-resistant nephrotic syndrome (SRNS) is associated with a high risk of developing end-stage renal disease. Biomarkers and analysis of genetic mutations may provide new information for prognosis in SRNS. Frequently relapsing and steroid-dependent NS is associated with long-term complications, including dyslipidemia, ...

  11. Preclinical rodent toxicity studies for long term use of ceftriaxone

    Directory of Open Access Journals (Sweden)

    Elena Ratti

    2015-01-01

    Ceftriaxone showed rapid absorption with half-life values ranging between 1 and 1.5 h. Additionally, there was no evidence of accumulation and a virtually complete elimination by 16 h after the last dose. Overall there were no toxicologically meaningful drug-related animal findings associated with the long-term administration (6 months of ceftriaxone. These results support safety of long-term use of ceftriaxone in human clinical trials.

  12. Seamless Long Term Learning in Agile Teams for Sustainable Leadership

    CERN Document Server

    Qureshi, M R J

    2012-01-01

    Seamless and continuous support for long term organizational learning needs is essential for long lasting progress of the organization. Agile process model provides an excellent opportunity to cater that specific problem and also helps in motivation, satisfaction, coordination, presentation and technical skills enhancement of agile teams. This long term learning process makes organization to sustain their current successes and lead both organization and team members to successful and dynamic market leaders.

  13. Teacher Cultural Competency and Long-Term English Language Learners

    OpenAIRE

    Wilson, Jannis

    2015-01-01

    Students that have been designated English Language Learners for five or more years are Long-Term English Learners. The literature review addresses some typical characteristics and experiences of students that are Long- Term English Language Learners, and the need for culturally responsive practices to meet their needs. Teacher attitudes, perceptions about English Language Learners, positionality, and opportunities to learn are integrated into the review. The author discusses linguistic aware...

  14. Commentary: The Broader Context of Long-Term Care Ethics.

    Science.gov (United States)

    Lesandrini, Jason; O'Connell, Carol

    2016-07-01

    Ethical issues in long-term care settings, although having received attention in the literature, have not in our opinion received the appropriate level they require. Thus, we applaud the Cambridge Quarterly for publishing this case. We can attest to the significance of ethical issues arising in long-term care facilities, as Mr. Hope's case is all too familiar to those practicing in these settings. What is unique about this case is that an actual ethics consult was made in a long-term care setting. We have seen very little in the published literature on the use of ethics structures in long-term care populations. Our experience is that these healthcare settings are ripe for ethical concerns and that providers, patients, families, and staff need/desire ethics resources to actively and preventively address ethical concerns. The popular press has begun to recognize the ethical issues involved in long-term care settings and the need for ethics structures. Recently, in California a nurse refused to initiate CPR for an elderly patient in a senior residence. In that case, the nurse was quoted as saying that the facility had a policy that nurses were not to start CPR for elderly patients. 1 Although this case is not exactly the same as that of Mr. Hope, it highlights the need for developing robust ethics program infrastructures in long-term care settings that work toward addressing ethical issues through policy, education, and active consultation.

  15. Planning long-term vegetation studies at landscape scales

    Science.gov (United States)

    Stohlgren, Thomas J.

    1995-01-01

    Long-term ecological research is receiving more attention now than ever before. Two recent books, Long-term Studies in Ecology: Approaches and Alternatives, edited by Gene Likens (1989), and Long-term Ecological Research: An International Perspective, edited by Paul Risser (1991), prompt the question, “Why are these books so thin?” Except for data from paleoecological, retrospective studies (see below), there are exceptionally few long-term data sets in terrestrial ecology (Strayer et al. 1986; Tilman 1989; this volume). In a sample of 749 papers published in Ecology, Tilman (1989) found that only 1.7% of the studies lasted at least five field seasons. Only one chapter in each of the review books dealt specifically with expanding both the temporal and the spatial scales of ecological research (Berkowitz et al. 1989; Magnuson et al. 1991). Judging by the growing number of landscape-scale long-term studies, however, such as the Long-Term Ecological Research (LTER) Program (Callahan 1991), the U.S. Environmental Protection Agency’s Environmental Monitoring and Assessment Program (EMAP; Palmer et al. 1991), the U.S. Army’s Land Condition-Trend Analysis (LCTA) Program (Diersing et al. 1992), and various agencies’ global change research programs (CEES 1993), there is a growing interest to expand ecological research both temporally and spatially.

  16. Development of cryopreservation methods for long-term preservation of cyanobacterial strains in the BCCM/ULC collection

    OpenAIRE

    Crahay, Charlotte; Renard, Marine; Mari, Maud; Day, John G.; Wilmotte, Annick

    2015-01-01

    Long-term genetic and functional stability is a fundamental requirement for the maintenance of microorganisms and cryopreservation is the preferred method for the long-term storage of many micro-organisms, including cyanobacteria. The BCCM/ULC collection currently holds 200 cyanobacterial strains, but only 62 are cryo-preserved. The main limiting factors are the low levels of survival of some strains and the long periods required to recover from cryopreservation, and thus the inability to del...

  17. Brines as Sources of Long-term Subsurface Contamination

    Science.gov (United States)

    Flowers, T. C.; Hunt, J. R.

    2004-12-01

    Concentrated salt solutions, i.e. brines, are source terms for environmental contaminants released into surface waters and groundwaters. Brines arise from both natural and industrial processes such as natural salt deposits, solid rocket fuel production, landfill leachates, nuclear fuel reprocessing, and acid rock drainage. Additionally, many of the in-situ remediation fluids that have been implemented at the pilot or the field scale are also classified as brines. While brines are miscible with water, mixing processes are slow in the subsurface and this constrains the dilution of contaminants present within brines and the delivery of remediation fluids to sites where reactions are needed. The mixing of brines during their vertical migration through aquifers is determined by aquifer permeability as well as differences in density and viscosity between the brine and the ambient groundwater. The stability criterion for brine displacement was predicted in 1952 by Hill and the resulting dispersion at the mixing front is quantified by a compilation of literature data and the acquisition of new experimental data. As brines sink through aquifers, they become emplaced in less accessible locations where mass transfer models predict that contaminants within brines are slowly released into flowing groundwater. For radioactive wastes and environmental contaminants with very low acceptable concentrations, groundwater quality can be impacted for decades. Field data from a cooling water disposal site suggest that a dense brine is likely still present as a source term 40 years after waste disposal was stopped. Overall, analysis of pollution sources, quantification of transport processes, generalization of laboratory data, and limited evaluation of field data indicate that brines represent long-term sources of groundwater contamination and that source control has not been seriously addressed.

  18. Stabilization of carbon-fiber cold field-emission cathodes with a dielectric coating.

    Science.gov (United States)

    Mousa, M S; Kelly, T F

    2003-01-01

    A comprehensive investigation has been carried out to determine the source of an inherent temporal instability in the spatial distribution and the electron emission current obtained from field-emitting carbon fiber tips. These instability effects were successfully overcome by coating the tip with a sub-micron layer of dielectric epoxy resin coating. The influence of the coating thickness was studied and an optimum thickness of 0.2-0.3 microm that produced high emission stability was found. A large reduction in the intensity fluctuations of the emission image, at this coating thickness is demonstrated by using chart recorder traces in addition to slow scans of an optically monitored screen signal. The current-voltage (I-V) characteristics were obtained at a threshold field that is a few times lower than that of the uncoated tip. At low emission current levels linear F-N plots were obtained with a slope value lower than that of the uncoated emitter. The spatial distribution consisted of a very bright spot without any internal structure. The total energy distribution of the emitted electrons demonstrated a non-metallic behavior. The spectra obtained consisted of a single peak for low currents and a double peak for higher currents. The electron energy was measured relative to the Fermi level of tungsten and a spectral shift was shown to be a function of the current. Experiments have shown that the coated tips are not affected by the variations of pressure conditions down to 10(-6) mbar. These results suggest that a resin coated fiber tip offers superior performance to tungsten as a cold field emission electron source. Numerous improvements in the performance are underway. This includes a variety of polymeric coatings and more emissive carbon fibers.

  19. Long-term greenhouse gas measurements from aircraft

    Directory of Open Access Journals (Sweden)

    A. Karion

    2012-10-01

    Full Text Available In March 2009 the NOAA/ESRL/GMD Carbon Cycle and Greenhouse Gases Group collaborated with the US Coast Guard (USCG to establish the Alaska Coast Guard (ACG sampling site, a unique addition to NOAA's atmospheric monitoring network. This collaboration takes advantage of USCG bi-weekly Arctic Domain Awareness (ADA flights, conducted with Hercules C-130 aircraft from March to November each year. NOAA has installed window-replacement inlet plates on two USCG C-130 aircraft and deploys a pallet with NOAA instrumentation on each ADA flight. Flights typically last 8 h and cover a very large area, traveling from Kodiak, AK in the south up to Barrow, AK in the north, and making altitude profiles near the coast as well as in the interior. NOAA instrumentation on each flight includes: a flask sampling system, a continuous CO2/CH4/CO/H2O analyzer, a continuous ozone analyzer, and an ambient temperature and humidity sensor. GPS time and location from the aircraft's navigation system are also collected. Air samples collected in flight are analyzed at NOAA/ESRL for the major greenhouse gases and a variety of halocarbons and hydrocarbons that influence climate, stratospheric ozone, and air quality. Instruments on this aircraft are designed and deployed to be able to collect air samples and data autonomously, so that NOAA personnel visit the site only for installation at the beginning of each season. We present an assessment of the cavity ring-down spectroscopy (CRDS CO2/CH4/CO/H2O analyzer performance operating on an aircraft over a three-year period. We describe the overall system for making accurate greenhouse gas measurements using a CRDS analyzer on an aircraft with minimal operator interaction. Short and long-term stability of the CRDS analyzer over a seven-month deployment period is better than 0.15 ppm, 2 ppb, and 5 ppb for CO2, CH4, CO respectively, considering

  20. Short- and long-term (trophic) purinergic signalling.

    Science.gov (United States)

    Burnstock, Geoffrey

    2016-08-05

    There is long-term (trophic) purinergic signalling involving cell proliferation, differentiation, motility and death in the development and regeneration of most systems of the body, in addition to fast purinergic signalling in neurotransmission, neuromodulation and secretion. It is not always easy to distinguish between short- and long-term signalling. For example, adenosine triphosphate (ATP) can sometimes act as a short-term trigger for long-term trophic events that become evident days or even weeks after the original challenge. Examples of short-term purinergic signalling during sympathetic, parasympathetic and enteric neuromuscular transmission and in synaptic transmission in ganglia and in the central nervous system are described, as well as in neuromodulation and secretion. Long-term trophic signalling is described in the immune/defence system, stratified epithelia in visceral organs and skin, embryological development, bone formation and resorption and in cancer. It is likely that the increase in intracellular Ca(2+) in response to both P2X and P2Y purinoceptor activation participates in many short- and long-term physiological effects.This article is part of the themed issue 'Evolution brings Ca(2+) and ATP together to control life and death'.

  1. Method for Water Management Considering Long-term Probabilistic Forecasts

    Science.gov (United States)

    Hwang, J.; Kang, J.; Suh, A. S.

    2015-12-01

    This research is aimed at predicting the monthly inflow of the Andong-dam basin in South Korea using long-term probabilistic forecasts to apply long-term forecasts to water management. Forecasted Cumulative Distribution Functions (CDFs) of monthly precipitation are plotted by combining the range of monthly precipitation based on proper Probability Density Function (PDF) in past data with probabilistic forecasts in each category. Ensembles of inflow are estimated by entering generated ensembles of precipitation based on the CDFs into the 'abcd' water budget model. The bias and RMSE between averages in past data and observed inflow are compared to them in forecasted ensembles. In our results, the bias and RMSE of average precipitation in the forecasted ensemble are bigger than in past data, whereas the average inflow in the forecasted ensemble is smaller than in past data. This result could be used for reference data to apply long-term forecasts to water management, because of the limit in the number of forecasted data for verification and differences between the Andong-dam basin and the forecasted regions. This research has significance by suggesting a method of applying probabilistic information in climate variables from long-term forecasts to water management in Korea. Original data of a climate model, which produces long-term probabilistic forecasts should be verified directly as input data of a water budget model in the future, so that a more scientific response in water management against uncertainty of climate change could be reached.

  2. Child maltreatment: pathway to chronic and long-term conditions?

    Science.gov (United States)

    Taylor, Julie; Bradbury-Jones, Caroline; Lazenbatt, Anne; Soliman, Francesca

    2016-09-01

    The manifesto Start Well, Live Better by the UK Faculty of Public Health (Start Well, Live Better-A Manifesto for the Public's Health. London: UK Faculty of Public Health, 2014) sets out 12 compelling priorities for the protection of people's health. The focus of this document is preventative, calling for a comprehensive strategy to target a wide-ranging set of challenges to public health; however, it fails to mention child maltreatment and its negative impact on long-term health outcomes. In this article, we explore the long-term negative consequences of child maltreatment and how these can be conceptually aligned with four different characteristics of long-term health conditions. We suggest that situating child maltreatment within a long-term conditions framework could have significant advantages and implications for practice, policy and research, by strengthening a commitment across disciplines to apply evidence-based principles linked with policy and evaluation and recognizing the chronic effects of maltreatment to concentrate public, professional and government awareness of the extent and impact of the issue. We argue that a public health approach is the most effective way of focusing preventative efforts on the long-term sequelae of child maltreatment and to foster cooperation in promoting children's rights to grow and develop in a safe and caring environment free from violence and abuse.

  3. Long-Term Stewardship Program Science and Technology Requirements

    Energy Technology Data Exchange (ETDEWEB)

    Joan McDonald

    2002-09-01

    Many of the United States’ hazardous and radioactively contaminated waste sites will not be sufficiently remediated to allow unrestricted land use because funding and technology limitations preclude cleanup to pristine conditions. This means that after cleanup is completed, the Department of Energy will have long-term stewardship responsibilities to monitor and safeguard more than 100 sites that still contain residual contamination. Long-term stewardship encompasses all physical and institutional controls, institutions, information, and other mechanisms required to protect human health and the environment from the hazards remaining. The Department of Energy Long-Term Stewardship National Program is in the early stages of development, so considerable planning is still required to identify all the specific roles and responsibilities, policies, and activities needed over the next few years to support the program’s mission. The Idaho National Engineering and Environmental Laboratory was tasked with leading the development of Science and Technology within the Long-Term Stewardship National Program. As part of that role, a task was undertaken to identify the existing science and technology related requirements, identify gaps and conflicts that exist, and make recommendations to the Department of Energy for future requirements related to science and technology requirements for long-term stewardship. This work is summarized in this document.

  4. Mesozoic long-term eustatic cycles and their uncertain hierarchy

    Institute of Scientific and Technical Information of China (English)

    Dmitry A.Ruban

    2015-01-01

    Global sea-level has changed in a cyclic manner through geologic history, but the regularities of these changes are yet to be fully understood. Despite certain (and sometimes significant) differences, the available Mesozoic eustatic curves permit the outlining of long-term eustatic cycles, which are provi-sionally defined as cycles recognizable at the stage level and higher. Interpretation of the Triassic eustatic curves indicates two orders of long-term cycles and a 1st-order sea-level rise throughout the entire period. The Jurassic eustatic curves imply cyclicity of one or two orders, and a 1st-order eustatic rise during the entire period is also evident. Most challenges are interpretations for the Cretaceous; two to four orders of long-term eustatic cycles can be established for this period. Generally, the hierarchy of the long-term eustatic cycles might have changed through the Mesozoic. If so, and if one considers differ-ences of cycles of the same order between the periods of this era, it is difficult to apply “standard”hi-erarchical classifications to the documented cycles. The hypothetical uncertainty of the hierarchy of the Mesozoic long-term eustatic cycles is an important challenge for modern researchers.

  5. Study on Wheat Yield Stability in Huaibei Lime Concretion Black Soil Area Based on Long-Term Fertilization Experiment%长期施肥下淮北砂姜黑土区小麦产量稳定性研究

    Institute of Scientific and Technical Information of China (English)

    陈欢; 曹承富; 孔令聪; 张存岭; 李玮; 乔玉强; 杜世州; 赵竹

    2014-01-01

    Objective The research was conducted to explore the responsive mechanism of wheat yield stability to long-term fertilization. [Method] Based on long-term fertilization experiment in Yangliu village of Anhui province, the trend of change in wheat average yield, annual fluctuation of wheat yield and soil nutrients content in 5 fertilization patterns were investigated:non-fertilization (CK), application of single chemical fertilizer (NPK), application of single organic fertilizer (M), mixed application of organic and chemical fertilizer with the same amount of nitrogen (MNPK), mixed application of organic and chemical fertilizer with the larger amount of nitrogen (HMNPK).[Result]It was discovered that wheat yield in CK showed a declining trend by 5.81 kg·hm-2·a-1, while fluctuated increasing emerged in fertilization treatments. Wheat yield trend line of HMNPK was in the first place, but MPK had been chasing after by 9.75 kg·hm-2·a-1. Wheat yield trend line of NPK was higher than M in the earlier stage of experiment, whereas it was caught up by M after 22 years. In respect of wheat average yield of 32 years, HMNPK and MNPK were higher than other fertilization treatments, with 5 544.3 kg·hm-2 and 5 200.6 kg·hm-2, respectively; NPK took the third place, by increasing 614.6% of that in the non-fertilization treatment; wheat yield increasing of M was the lowest, however, no obvious difference was found between M and NPK. The contribution of soil capacity in lime concretion black soil had been decreasing in early 10 years then stopped and kept stable at 10%;the contribution ratio of fertilizer had been increasing in early 10 years, and then maintained dynamic balance at the level of 80%-90%. It enhanced the coefficient of variation (CV) and reduced sustainable yield index (SYI) without fertilization, which made yield stability the worst;the wheat yield stability of HMNPK and MNPK was better than NPK which was better than M. Compared with CK, fertilizer application

  6. Attenuated long-term Arc expression in the aged fascia dentata

    OpenAIRE

    2010-01-01

    One prominent component of aging is a defect in memory stabilization. To understand how the formation of enduring memories is altered in the aged brain, long-term markers of the biological events that may mediate memory consolidation were used to examine the activity dynamics of hippocampal circuits over extended intervals. The immediate-early gene Arc, which is implicated in both durable memory and synaptic plasticity, is expressed in the fascia dentata (FD) for long periods following behavi...

  7. Long-term soil transplant simulating climate change with latitude significantly alters microbial temporal turnover

    OpenAIRE

    2015-01-01

    To understand soil microbial community stability and temporal turnover in response to climate change, a long-term soil transplant experiment was conducted in three agricultural experiment stations over large transects from a warm temperate zone (Fengqiu station in central China) to a subtropical zone (Yingtan station in southern China) and a cold temperate zone (Hailun station in northern China). Annual soil samples were collected from these three stations from 2005 to 2011, and microbial com...

  8. Long-term flow monitoring of submarine gas emanations

    Science.gov (United States)

    Spickenbom, K.; Faber, E.; Poggenburg, J.; Seeger, C.

    2009-04-01

    One of the Carbon Capture and Storage (CCS) strategies currently under study is the sequestration of CO2 in sub-seabed geological formations. Even after a thorough review of the geological setting, there is the possibility of leaks from the reservoirs. As part of the EU-financed project CO2ReMoVe (Research, Monitoring, Verification), which aims to develop innovative research and technologies for monitoring and verification of carbon dioxide geological storage, we are working on the development of submarine long-term gas flow monitoring systems. Technically, however, these systems are not limited to CO2 but can be used for monitoring of any free gas emission (bubbles) on the seafloor. The basic design of the gas flow sensor system was derived from former prototypes developed for monitoring CO2 and CH4 on mud volcanoes in Azerbaijan. This design was composed of a raft floating on the surface above the gas vent to collect the bubbles. Sensors for CO2 flux and concentration and electronics for data storage and transmission were mounted on the raft, together with battery-buffered solar panels for power supply. The system was modified for installation in open sea by using a buoy instead of a raft and a funnel on the seafloor to collect the gas, which is then guided above water level through a flexible tube. Besides some technical problems (condensed water in the tube, movement of the buoys due to waves leading to biased measurement of flow rates), this setup provides a cost-effective solution for shallow waters. However, a buoy interferes with ship traffic, and it is also difficult to adapt this design to greater water depths. These requirements can best be complied by a completely submersed system. To allow unattended long-term monitoring in a submarine environment, such a system has to be extremely durable. Therefore, we focussed on developing a mechanically and electrically as simple setup as possible, which has the additional advantage of low cost. The system

  9. Abrupt vegetation transitions characterise long-term Amazonian peatland development

    Science.gov (United States)

    Roucoux, K. H.; Baker, T. R.; Gosling, W. D.; Honorio Coronado, E.; Jones, T. D.; Lahteenoja, O.; Lawson, I. T.

    2012-04-01

    Recent investigations of wetlands in western Amazonia have revealed the presence of extensive peatlands with peat deposits of up to 8 m-thick developing under a variety of vegetation types (Lähteenoja et al. 2012). Estimated to cover 150,000 km2 (Schulman et al. 1999), these peatlands make a valuable contribution to landscape and biological diversity and represent globally important carbon stores. In order to understand the processes leading to peat formation, and the sensitivity of these environments to future climatic change, it is necessary to understand their long-term history. The extent to which peatland vegetation changes over time, the stability of particular communities, the controls on transitions between vegetation types and how these factors relate to the accumulation of organic matter are not yet known. We report the first attempt to establish the long-term (millennial scale) vegetation history of a recently-described peatland site: Quistococha, a palm swamp, or aguajal, close to Iquitos in northern Peru. The vegetation is dominated by Mauritia flexuosa and Mauritiella armata and occupies a basin which is thought to be an abandoned channel of the River Amazon. We obtained a 4 m-long peat sequence from the deepest part of the basin. AMS-radiocarbon dating yielded a maximum age of 2,212 cal yr BP for the base of the peat, giving an average accumulation rate of 18 cm per century. Below the peat are 2 m of uniform, largely inorganic pale grey clays of lacustrine origin, which are underlain by an unknown thickness of inorganic sandy-silty clay of fluvial origin. Pollen analysis, carried out at c. 88-year intervals, shows the last 2,212 years to be characterised by the development of at least four distinct vegetation communities, with peat accumulating throughout. The main phases were: (1) Formation of Cyperaceae (sedge) fen coincident with peat initiation; (2) A short-lived phase of local Mauritia/Mauritiella development; (3) Development of mixed wet

  10. Experience with long-term use of certolizumab pegol (Cimzia

    Directory of Open Access Journals (Sweden)

    Karine Arnoldovna Lytkina

    2013-01-01

    /week as DMARD therapy. One patient with a maximum DAS28 score of 3.16 by the end of the protocol continued to be treated with CZP (200 mg subcutaneously once two weekly. Another female patient with moderate RA activity at the end of therapy herself completed the treatment with a TNF-α inhibitor.  Following a year, 2 patients remained in sustained RA remission and did not need a GEBA. RA activity increased in a female patient who had stopped treatment; she was recommended to resume therapy with the TNF-α inhibitor. Another female patient was stated to have a low RA activity and her follow-up was continued Conclusion. The findings are evidence in favor of the fact that long-term combination therapy with a TNF-α inhibitor in combination with MTX may lead to not only sustained RA remission, but also its maintenance even after a GEBA was discontinued. The use of CZP for 6.5 years induced remission and promoted stability in some patients during a year after drug discontinuation.

  11. Experience with long-term use of certolizumab pegol (Cimzia

    Directory of Open Access Journals (Sweden)

    Karine Arnoldovna Lytkina

    2013-10-01

    /week as DMARD therapy. One patient with a maximum DAS28 score of 3.16 by the end of the protocol continued to be treated with CZP (200 mg subcutaneously once two weekly. Another female patient with moderate RA activity at the end of therapy herself completed the treatment with a TNF-α inhibitor.  Following a year, 2 patients remained in sustained RA remission and did not need a GEBA. RA activity increased in a female patient who had stopped treatment; she was recommended to resume therapy with the TNF-α inhibitor. Another female patient was stated to have a low RA activity and her follow-up was continued Conclusion. The findings are evidence in favor of the fact that long-term combination therapy with a TNF-α inhibitor in combination with MTX may lead to not only sustained RA remission, but also its maintenance even after a GEBA was discontinued. The use of CZP for 6.5 years induced remission and promoted stability in some patients during a year after drug discontinuation.

  12. Conversion of short-term to long-term memory in the novel object recognition paradigm.

    Science.gov (United States)

    Moore, Shannon J; Deshpande, Kaivalya; Stinnett, Gwen S; Seasholtz, Audrey F; Murphy, Geoffrey G

    2013-10-01

    It is well-known that stress can significantly impact learning; however, whether this effect facilitates or impairs the resultant memory depends on the characteristics of the stressor. Investigation of these dynamics can be confounded by the role of the stressor in motivating performance in a task. Positing a cohesive model of the effect of stress on learning and memory necessitates elucidating the consequences of stressful stimuli independently from task-specific functions. Therefore, the goal of this study was to examine the effect of manipulating a task-independent stressor (elevated light level) on short-term and long-term memory in the novel object recognition paradigm. Short-term memory was elicited in both low light and high light conditions, but long-term memory specifically required high light conditions during the acquisition phase (familiarization trial) and was independent of the light level during retrieval (test trial). Additionally, long-term memory appeared to be independent of stress-mediated glucocorticoid release, as both low and high light produced similar levels of plasma corticosterone, which further did not correlate with subsequent memory performance. Finally, both short-term and long-term memory showed no savings between repeated experiments suggesting that this novel object recognition paradigm may be useful for longitudinal studies, particularly when investigating treatments to stabilize or enhance weak memories in neurodegenerative diseases or during age-related cognitive decline.

  13. LONG-TERM EFFECT OF HOMOHARRINGTONINE ON CHRONIC GRANULOCYTIC LEUKEMIA

    Institute of Scientific and Technical Information of China (English)

    LI Yu-feng; ZHU Jia-bin; WANG Chun-ling; DING Bang-he; LI Yuan-yuan; XUAN Heng-bao; QIAN Mo-sheng

    2005-01-01

    Objective: To observe the long-term effect of homoharringtonine (HHT) on chronic granulocytic leukemia (CGL) and its pharmacological mechanism. Methods: 76 patients with newly diagnosed early chronic phase CGL received treatment of merely 1.5 mg/m2 daily HHT for induction remission and long-term maintenance treatment. The apoptosis rate of bone marrow CD34+ cells induced by HHT was assayed with flow cytometer. Results: 86.8% patients achieved CHR, 13.2% patients PHR and 31.8% patients got cytogenetic response in HHT treatment group, which was longer than 31 (8-54) months in hydroxyurea (HU) group (P<0.05). The effect of apoptosis induction HHT was stronger on CGL-CP patients bone marrow CD34+ cells than on normal person bone marrow CD34+ cells. Conclusion: HHT is a very effective drug for remission induction and long-term maintenance treatment in early chronic phase CGL patients.

  14. Using long-term transit timing to detect terrestrial planets

    CERN Document Server

    Heyl, J S; Heyl, Jeremy S.; Gladman, Brett J.

    2006-01-01

    We propose that the presence of additional planets in extrasolar planetary systems can be detected by long-term transit timing studies. If a transiting planet is on an eccentric orbit then the presence of another planet causes a secular advance of the transiting planet's pericenter over and above the effect of general relativity. Although this secular effect is impractical to detect over a small number of orbits, it causes long-term differences in when future transits occur, much like the long-term decay observed in pulsars. Measuring this transit-timing delay would thus allow the detection of either one or more additional planets in the system or the first measurements of non-zero oblateness ($J_2$) of the central stars.

  15. Long-term impact of sales promotion on brand image

    Directory of Open Access Journals (Sweden)

    Danijela Mandić

    2009-12-01

    Full Text Available Sales promotion (SP is an inevitable tool in the marketing communications mix, especially in the FMCG markets, due to pressures such as retailers’ growing demands and increasing competition. This has proven to be an issue for many companies, especially those with a premium brand positioning and those concerned about the impact that SP might have on the long-term image of the company. Despite the fact that literature is replete with research on SP, it seems to be vastly generalized and mostly focused on price reductions. Thus, this paper aims to analyze and discuss the issue of the long-term impact that SP has on companies, especially on premium brands in the FMCG markets. It concludes that, when used properly and strategically, SP may have a positive long-term impact on brands.

  16. Long-term drought severity variations in Morocco

    Science.gov (United States)

    Esper, Jan; Frank, David; Büntgen, Ulf; Verstege, Anne; Luterbacher, Jürg; Xoplaki, Elena

    2007-09-01

    Cedrus atlantica ring width data are used to reconstruct long-term changes in the Palmer Drought Severity Index (PDSI) over the past 953 years in Morocco, NW Africa. The reconstruction captures the dry conditions since the 1980s well and places this extreme period within a millennium-long context. PDSI values were above average for most of the 1450-1980 period, which let recent drought appear exceptional. However, our results also indicate that this pluvial episode of the past millennium was preceded by generally drier conditions back to 1049. Comparison of PDSI estimates with large-scale pressure field reconstructions revealed steady synoptic patterns for drought conditions over the past 350 years. The long-term changes from initially dry to pluvial to recent dry conditions are similar to PDSI trends reported from N America, and we suggest that they are related to long-term temperature changes, potentially teleconnected with ENSO variability and forced by solar irradiance changes.

  17. Being a long-term user of nicotine replacement therapy

    DEFF Research Database (Denmark)

    Borup, Gitte; Nørgaard, Lotte Stig; Tønnesen, Philip;

    Background During recent years a gradual shift in the application of nicotine replacement therapy (NRT) has taken place from NRT-products only being recommended to achieve smoking cessation, to now including smoking reduction, and long-term substitution of tobacco with NRT has taken place. This has...... been promoted as a way of achieving harm-reduction in highly nicotine dependent smokers who are unwilling or incapable of quitting all nicotine products, as continued use of NRT is widely accepted as being far less hazardous than continued smoking. To our knowledge no previous research has been done......, regarding long-term NRT users’ experiences with continuing the use of NRT. Results from a survey study among long-term NRT-users, who had used NRT for 12 months or more, found that out of 92 former smokers 88 % wished to quit using NRT. The primary causes stated for wishing to quit were being tired...

  18. Marijuana effects on long-term memory assessment and retrieval.

    Science.gov (United States)

    Darley, C F; Tinklenberg, J R; Roth, W T; Vernon, S; Kopell, B S

    1977-05-01

    The ability of 16 college-educated male subjects to recall from long-term memory a series of common facts was tested during intoxication with marijuana extract calibrated to 0.3 mg/kg delta-9-tetrahydrocannabinol and during placebo conditions. The subjects' ability to assess their memory capabilities was then determined by measuring how certain they were about the accuracy of their recall performance and by having them predict their performance on a subsequent recognition test involving the same recall items. Marijuana had no effect on recall or recognition performance. These results do not support the view that marijuana provides access to facts in long-term storage which are inaccessible during non-intoxication. During both marijuana and placebo conditions, subjects could accurately predict their recognition memory performance. Hence, marijuana did not alter the subjects' ability to accurately assess what information resides in long-term memory even though they did not have complete access to that information.

  19. Long-term visual tracking based on correlation filters

    Science.gov (United States)

    Wei, Quanlu; Lao, Songyang; Bai, Liang

    2017-03-01

    In order to accomplish the long term visual tracking task in complex scenes, solve problems of scale variation, appearance variation and tracking failure, a long term tracking algorithm is given based on the framework of collaborative correlation tracking. Firstly, we integrate several powerful features to boost the represent ability based on the kernel correlation filter, and extend the filter by embedding a scale factor into the kernelized matrix to handle the scale variation. Then, we use the Peak-Sidelobe Ratio to decide whether the object is tracked successfully, and a CUR filter for re-detection the object in case of tracking failure is learnt with random sampling. Corresponding experiment is performed on 17 challenging benchmark video sequences. Compared with the 8 existing state-of-the-art algorithms based on discriminative learning method, the results show that the proposed algorithm improves the tracking performance on several indexes, and is robust to complex scenes for long term visual tracking.

  20. Sexuality and Physical Intimacy in Long Term Care

    Science.gov (United States)

    Lichtenberg, Peter A.

    2015-01-01

    Sexuality and sexual needs in older adults remains a neglected area of clinical intervention, particularly so in long term care settings. Because older adults in medical rehabilitation and long term care beds present with significant frailties, and often significant neurocognitive disorders it makes it difficult for occupational therapists and other staff to evaluate the capacity of an older adult resident to participate in sexual relationships. The current paper reviews the current literature on sexuality and aging, examines some of the clinical practices and guidelines regarding sexual expression in long term care and presents two case examples. A semi-structured interview and decision tree is presented to assist therapists in making careful and informed decisions and thereby balancing needs for protection with needs for autonomy. PMID:24354331