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Sample records for accumulation mode range

  1. Comparison of flash and accumulation mode in range-gated active imaging

    NASA Astrophysics Data System (ADS)

    Christnacher, Frank; Laurenzis, Martin; Schertzer, Stéphane

    2013-10-01

    Range-gated active imaging has significantly been improved in the recent past. Due to the availability of high power laser diodes around 800-860 nm, it is now possible to find off-the-shelf systems working with very sensitive light intensifier and laser diodes. On the other hand, eye-safe systems working around 1.5 μm suffer from a lack of intensified sensor in the SWIR band. The only existing intensified sensors require the use of high power pulsed laser sources for the illumination. Consequently, the type of source (diode or solid-state laser) gives fundamental differences between the two types of system. The first technique which uses laser diodes, μchip or fiber lasers, is called "accumulation" imaging. These sources are characterized by a low-pulse power and high repetition rate, mostly around a few tens of kHz. Here, each image is the result of the accumulation of hundred of pulses during the frame time. The second technique which uses a solid-state laser illumination is called "flash" imaging. Here, each image is the result of a unique high power illumination of the scene at low repetition rate, mostly around the video rate. In this paper, we investigate the theoretical and practical differences between these two imaging modes and its influence on image quality, on sensitivity to day light or stray light, on fog penetration capacity, on its sensitivity to turbulences and on laser safety (NOHD). For comparative experimental purposes, we've built a range-gated active imaging system which allows the investigation of both methods. We've carried out precise comparative studies between the two acquisition methods.

  2. Analysis and comparison of rangerange positioning mode and hyperbolic positioning mode

    NASA Astrophysics Data System (ADS)

    Chen, Shi-Ru; Xu, Ding-Jie; Sun, Yao

    2002-06-01

    Three key factors are discussed, which affect positioning accuracy of rangerange positioning mode and hyperbolic positioning mode. Based on the error elliptical theory, the expressions of positioning error and of positioning geometric factor of rangerange positioning mode and hyperbolic positioning mode are derived, and the positioning error and the blind positioning area of two different positioning modes are analyzed. According to the requirement of navigation area, an optimum positional configuration among navigation stations of hyperbolic positioning mode is provided. Some considerable conclusions are obtained, and some graphs of distribution are presented, which are important to study and design a reasonable, precise radio navigation system.

  3. Germanium accumulation-mode charge-injection-device process

    NASA Technical Reports Server (NTRS)

    Moore, T. G.

    1981-01-01

    Gallium doped germanium is suitable for applications in the detection of far infrared radiation. Measurements were made on experimental photoconductors (PCs), accumulation mode charge injection devices (AMCIDs), and the SSPC (a switched, sampled PC alternative to the AMCID). The results indicate that the SSPC, which had a responsivity near 1.5 amp/watt, is desirable for use in two dimensional detector arrays.

  4. Screening for new accumulator plants in Andes Range mines

    NASA Astrophysics Data System (ADS)

    Bech, Jaume; Roca, Núria

    2016-04-01

    Toxic metal pollution of waters and soils is a major environmental problem, and most conventional remediation approaches do not provide acceptable solutions. The use of plants or plant products to restore or stabilize contaminated sites, collectively known as phytoremediation, takes advantage of the natural abilities of plants to take up, accumulate, store, or degrade organic and inorganic substances. Although not a new concept, phytoremediation is currently being re-examined as an environmentally friendly, cost-effective means of reducing metal contaminated soil. Plants growing on naturally metal-enriched soils are of particular interest in this regard, since they are genetically tolerant to high metal concentrations and have an excellent adaptation to this multi-stress environment. Processes include using plants that tolerate and accumulate metals at high levels (phytoextraction) and using plants that can grow under conditions that are toxic to other plants while preventing, for example, soil erosion (phytostabilization). Soil and plant samples were taken at polymetallic mines in Peru, Ecuador and Chile. It is suggested that Plantago orbignyana Steinheil is a Pb hyperaccumulator. Moreover, unusually elevated concentrations of Pb (over 1000 mg kg-1) and Translocation Factor (TF) greater than one were also detected in shoots of 6 different plants species (Ageratina sp., Achirodine alata, Cortaderia apalothica, Epilobium denticulatum, Taraxacum officinalis and Trifolium repens) of a Caroline mine in Perú. Among the grass species (Poaceae), the highest shoot As concentration were found in Paspalum sp. (>1000 μg g-1) and Eriochola ramose (460 μg g-1) from the Cu mine in Peru and in Holcus lanatus and Pennisetum clandestinum (>200 μg g-1) from the silver mine in Ecuador. The shoot accumulation of Zn was highest in Baccharis amdatensis (>1900 μg g-1) and in Rumex crispus (1300 μg g-1) from the Ag mine in Ecuador (Bech et al., 2002). Paspalum racemosum also

  5. Long-range surface modes supported by thin films

    NASA Astrophysics Data System (ADS)

    Yang, Fuzi; Sambles, J. R.; Bradberry, G. W.

    1991-09-01

    A detailed analysis of the surface modes of a thin slab of material of dielectric constant ɛ2 (=ɛr2-iɛi2) surrounded symmetrically by dielectric media is presented. Results show that in the thin-film limit, as well as the well-known long-range surface plasmon for a thin metal layer and the TM guided mode for a thin dielectric, a long-range surface mode exists for almost any value of ɛ2. This is even true if the imaginary part of ɛ2, ɛi2, is much larger than the real part ɛr2. We also find that a long-range surface mode may arise from the coupling between two surfaces which individually cannot support a surface mode. These are a pair of special coupled-surface modes which may exist below a certain critical film thickness and which have two separate propagation vectors each with the same field symmetry. It is also found that the inverse situation may pertain, that is for certain relative values of dielectric constants even though ordinary surface modes may exist, below a critical thickness the resulting coupled long-range mode no longer exists. The analysis has also been extended to practical situations with weakly absorbing surrounding media and to circumstances where the dielectric constants of the surrounding media are slightly different. Both of these effects modify the dispersion relations obtained for the simple case and introduce further limit thicknesses into the problem. Analytic formulas in the thin-film limit are presented for all the above situations and field distributions and energy flow (Poynting vector) profiles presented to illustrate as necessary the nature of the modes supported by these systems. Finally experimental results are presented which illustrate the rather sweeping conclusion that a long-range surface mode may exist on a thin film for almost all values of ɛr2 and ɛi2. This result paves the way for a range of optics experiments on absorbing structures.

  6. Density dependence of electron mobility in the accumulation mode for fully depleted SOI films

    SciTech Connect

    Naumova, O. V. Zaitseva, E. G.; Fomin, B. I.; Ilnitsky, M. A.; Popov, V. P.

    2015-10-15

    The electron mobility µ{sub eff} in the accumulation mode is investigated for undepleted and fully depleted double-gate n{sup +}–n–n{sup +} silicon-on-insulator (SOI) metal–oxide–semiconductor field-effect transistors (MOSFET). To determine the range of possible values of the mobility and the dominant scattering mechanisms in thin-film structures, it is proposed that the field dependence of the mobility µ{sub eff} be replaced with the dependence on the density N{sub e} of induced charge carriers. It is shown that the dependences µ{sub eff}(N{sub e}) can be approximated by the power functions µ{sub eff}(N{sub e}) ∝ N{sub e}{sup -n}, where the exponent n is determined by the chargecarrier scattering mechanism as in the mobility field dependence. The values of the exponent n in the dependences µ{sub eff}(N{sub e}) are determined when the SOI-film mode near one of its surfaces varies from inversion to accumulation. The obtained results are explained from the viewpoint of the electron-density redistribution over the SOI-film thickness and changes in the scattering mechanisms.

  7. The organic fraction of bubble-generated, accumulation mode Sea Spray Aerosol (SSA)

    NASA Astrophysics Data System (ADS)

    Modini, R. L.; Harris, B.; Ristovski, Z. D.

    2010-03-01

    Recent studies have detected a dominant accumulation mode (~100 nm) in the Sea Spray Aerosol (SSA) number distribution. There is evidence to suggest that particles in this mode are composed primarily of organics. To investigate this hypothesis we conducted experiments on NaCl, artificial SSA and natural SSA particles with a Volatility-Hygroscopicity-Tandem-Differential-Mobility-Analyser (VH-TDMA). NaCl particles were atomiser generated and a bubble generator was constructed to produce artificial and natural SSA particles. Natural seawater samples for use in the bubble generator were collected from biologically active, terrestrially-affected coastal water in Moreton Bay, Australia. Differences in the VH-TDMA-measured volatility curves of artificial and natural SSA particles were used to investigate and quantify the organic fraction of natural SSA particles. Hygroscopic Growth Factor (HGF) data, also obtained by the VH-TDMA, were used to confirm the conclusions drawn from the volatility data. Both datasets indicated that the organic fraction of our natural SSA particles evaporated in the VH-TDMA over the temperature range 170-200 °C. The organic volume fraction for 71-77 nm natural SSA particles was 8±6%. Organic volume fraction did not vary significantly with varying water residence time (40 s to 24 h) in the bubble generator or SSA particle diameter in the range 38-173 nm. At room temperature we measured shape- and Kelvin-corrected HGF at 90% RH of 2.46±0.02 for NaCl, 2.35±0.02 for artifical SSA and 2.26±0.02 for natural SSA particles. Overall, these results suggest that the natural accumulation mode SSA particles produced in these experiments contained only a minor organic fraction, which had little effect on hygroscopic growth. Our measurement of 8±6% is an order of magnitude below two previous measurements of the organic fraction in SSA particles of comparable sizes. We stress that our results were obtained using coastal seawater and they can't necessarily

  8. The organic fraction of bubble-generated, accumulation mode Sea Spray Aerosol (SSA)

    NASA Astrophysics Data System (ADS)

    Modini, R. L.; Harris, B.; Ristovski, Z. D.

    2009-10-01

    Recent studies have detected a dominant accumulation mode (~100 nm) in the Sea Spray Aerosol (SSA) number distribution. There is evidence to suggest that particles in this mode are composed primarily of organics. To investigate this hypothesis we conducted experiments on NaCl, artificial SSA and natural SSA particles with a Volatility-Hygroscopicity-Tandem-Differential-Mobility-Analyser (VH-TDMA). NaCl particles were atomiser generated and a bubble generator was constructed to produce artificial and natural SSA particles. Natural seawater samples for use in the bubble generator were collected from biologically active, terrestrially-affected coastal water in Moreton Bay, Australia. Differences in the VH-TDMA-measured volatility curves of artificial and natural SSA particles were used to investigate and quantify the organic fraction of natural SSA particles. Hygroscopic Growth Factor (HGF) data, also obtained by the VH-TDMA, were used to confirm the conclusions drawn from the volatility data. Both datasets indicated that the organic fraction of our natural SSA particles evaporated in the VH-TDMA over the temperature range 170-200°C. The organic volume fraction for 71-77 nm natural SSA particles was 8±6%. Organic volume fraction did not vary significantly with varying water residence time (40 s0 to 24 h) in the bubble generator or SSA particle diameter in the range 38-173 nm. At room temperature we measured shape- and Kelvin-corrected HGF at 90% RH of 2.46±0.02 for NaCl, 2.35±0.02 for artifical SSA and 2.26±0.02 for natural SSA particles. Overall, these results suggest that the natural accumulation mode SSA particles produced in these experiments contained only a minor organic fraction, which had little effect on hygroscopic growth. Our measurement of 8±6% is an order of magnitude below two previous measurements of the organic fraction in SSA particles of comparable sizes. Further studies with a variety of different seawaters are required to better quantify how

  9. Terahertz generation in GaN diodes in the limited space-charge accumulation mode

    NASA Astrophysics Data System (ADS)

    Barry, E. A.; Sokolov, V. N.; Kim, K. W.; Trew, R. J.

    2008-06-01

    The conditions for terahertz power generation are investigated theoretically in a nanoscale GaN-based diode coupled to an external resonant circuit for operation in the limited space-charge accumulation (LSA) mode under the high-field transport regime. The generation criteria are revisited in terms of a phase plane analysis of the diode high-field transport and circuit equations. Based on a Fourier series analysis, the waveforms of the diode voltage and current are examined and the generated power and conversion efficiencies are estimated at the fundamental and lowest harmonic frequencies. The advantages of group-III nitride LSA diodes are elucidated including their ability to simultaneously achieve large output powers (>10 mW) and high dc-to-rf conversion efficiencies (>1%) over a wide range of frequencies near 1 THz.

  10. Performances of accumulation-mode n- and p-MOSFETs on Si(110) wafers

    NASA Astrophysics Data System (ADS)

    Gaubert, Philippe; Teramoto, Akinobu; Sugawa, Shigetoshi

    2017-04-01

    In this study, we investigate the electrical and noise performances of accumulation-mode n- and p-MOSFETs on Si(110) wafers and compare them with conventional MOSFETs fabricated either on Si(100) or Si(110) wafers. With regard to electrical performances, accumulation-mode p-type MOSFETs are in every aspect superior. However, its n-type counterpart does not provide the best performances even though they are still superior to conventional transistors when fabricated on the same type of wafer. Conventional inversion-mode n-MOSFETs on Si(100) wafers still display the best performances. The simultaneous improvement and reduction in drivability respectively in the p- and n-type transistors make the accumulation-mode MOSFETs fabricated on Si(110) wafers extremely well suited for complementary technologies owing to their great balance in terms of drivability. With regard to noise evaluation, accumulation-mode MOSFETs on Si(110) wafers exhibit the highest noise level even though they compare relatively well with the inversion transistors on Si(110) wafers, especially for p-type ones. The lowest noise level is obtained for conventional inversion-mode MOSFETs on Si(100) wafers, and the type of wafer upon which transistors are fabricated is the reason. Indeed, the fabrication of high-quality Si/SiO2 interfaces is better achieved for silicon wafers with a (100) crystallographic orientation, leading to few interface defects and consequently less noise.

  11. Dual Mode NOx Sensor: Measuring Both the Accumulated Amount and Instantaneous Level at Low Concentrations

    PubMed Central

    Groß, Andrea; Beulertz, Gregor; Marr, Isabella; Kubinski, David J.; Visser, Jaco H.; Moos, Ralf

    2012-01-01

    The accumulating-type (or integrating-type) NOx sensor principle offers two operation modes to measure low levels of NOx: The direct signal gives the total amount dosed over a time interval and its derivative the instantaneous concentration. With a linear sensor response, no baseline drift, and both response times and recovery times in the range of the gas exchange time of the test bench (5 to 7 s), the integrating sensor is well suited to reliably detect low levels of NOx. Experimental results are presented demonstrating the sensor’s integrating properties for the total amount detection and its sensitivity to both NO and to NO2. We also show the correlation between the derivative of the sensor signal and the known gas concentration. The long-term detection of NOx in the sub-ppm range (e.g., for air quality measurements) is discussed. Additionally, a self-adaption of the measurement range taking advantage of the temperature dependency of the sensitivity is addressed. PMID:22736980

  12. Solid state long range surface plasmon polariton single mode lasers

    NASA Astrophysics Data System (ADS)

    Karami Keshmarzi, Elham; Tait, R. Niall; Berini, Pierre

    2013-10-01

    Incorporation of a solid-state gain medium in the cladding of a Long Range Surface Plasmon Polariton (LRSPP) waveguide in order to create a single-mode near-infrared laser source is proposed. LRSPP Bragg gratings based on stepping the width of the metal strip are used to form the laser's cavity. Three laser configurations are presented: The first 2 lasers employ DBRs (Distributed Bragg Reflectors) in ECL (External Cavity Laser) architecture while the third is based on the DFB (Distributed Feedback) configuration. All 3 configurations are thermally tunable by heating the gratings directly by injecting current. The lasers are convenient to fabricate leading to inexpensive sources that could be used in optical integrated circuits or waveguide biosensors.

  13. Long-range spin accumulation from heat injection in mesoscopic superconductors with Zeeman splitting.

    PubMed

    Silaev, M; Virtanen, P; Bergeret, F S; Heikkilä, T T

    2015-04-24

    We describe far-from-equilibrium nonlocal transport in a diffusive superconducting wire with a Zeeman splitting, taking into account different spin relaxation mechanisms. We demonstrate that due to the Zeeman splitting, an injection of current in a superconducting wire creates spin accumulation that can only relax via thermalization. This effect leads to a long-range spin accumulation detectable in the nonlocal signal. Our model gives a qualitative explanation and provides accurate fits of recent experimental results in terms of realistic parameters.

  14. Conduction Threshold in Accumulation-Mode InGaZnO Thin Film Transistors

    NASA Astrophysics Data System (ADS)

    Lee, Sungsik; Nathan, Arokia

    2016-03-01

    The onset of inversion in the metal-oxide-semiconductor field-effect transistor (MOSFET) takes place when the surface potential is approximately twice the bulk potential. In contrast, the conduction threshold in accumulation mode transistors, such as the oxide thin film transistor (TFT), has remained ambiguous in view of the complex density of states distribution in the mobility gap. This paper quantitatively describes the conduction threshold of accumulation-mode InGaZnO TFTs as the transition of the Fermi level from deep to tail states, which can be defined as the juxtaposition of linear and exponential dependencies of the accumulated carrier density on energy. Indeed, this permits direct extraction and visualization of the threshold voltage in terms of the second derivative of the drain current with respect to gate voltage.

  15. Conduction Threshold in Accumulation-Mode InGaZnO Thin Film Transistors

    PubMed Central

    Lee, Sungsik; Nathan, Arokia

    2016-01-01

    The onset of inversion in the metal-oxide-semiconductor field-effect transistor (MOSFET) takes place when the surface potential is approximately twice the bulk potential. In contrast, the conduction threshold in accumulation mode transistors, such as the oxide thin film transistor (TFT), has remained ambiguous in view of the complex density of states distribution in the mobility gap. This paper quantitatively describes the conduction threshold of accumulation-mode InGaZnO TFTs as the transition of the Fermi level from deep to tail states, which can be defined as the juxtaposition of linear and exponential dependencies of the accumulated carrier density on energy. Indeed, this permits direct extraction and visualization of the threshold voltage in terms of the second derivative of the drain current with respect to gate voltage. PMID:26932790

  16. Automatic dynamic range adjustment for ultrasound B-mode imaging.

    PubMed

    Lee, Yeonhwa; Kang, Jinbum; Yoo, Yangmo

    2015-02-01

    In medical ultrasound imaging, dynamic range (DR) is defined as the difference between the maximum and minimum values of the displayed signal to display and it is one of the most essential parameters that determine its image quality. Typically, DR is given with a fixed value and adjusted manually by operators, which leads to low clinical productivity and high user dependency. Furthermore, in 3D ultrasound imaging, DR values are unable to be adjusted during 3D data acquisition. A histogram matching method, which equalizes the histogram of an input image based on that from a reference image, can be applied to determine the DR value. However, it could be lead to an over contrasted image. In this paper, a new Automatic Dynamic Range Adjustment (ADRA) method is presented that adaptively adjusts the DR value by manipulating input images similar to a reference image. The proposed ADRA method uses the distance ratio between the log average and each extreme value of a reference image. To evaluate the performance of the ADRA method, the similarity between the reference and input images was measured by computing a correlation coefficient (CC). In in vivo experiments, the CC values were increased by applying the ADRA method from 0.6872 to 0.9870 and from 0.9274 to 0.9939 for kidney and liver data, respectively, compared to the fixed DR case. In addition, the proposed ADRA method showed to outperform the histogram matching method with in vivo liver and kidney data. When using 3D abdominal data with 70 frames, while the CC value from the ADRA method is slightly increased (i.e., 0.6%), the proposed method showed improved image quality in the c-plane compared to its fixed counterpart, which suffered from a shadow artifact. These results indicate that the proposed method can enhance image quality in 2D and 3D ultrasound B-mode imaging by improving the similarity between the reference and input images while eliminating unnecessary manual interaction by the user.

  17. Nutritional mode influences lipid accumulation in microalgae with the function of carbon sequestration and nutrient supplementation.

    PubMed

    Prathima Devi, M; Swamy, Y V; Venkata Mohan, S

    2013-08-01

    Effect of nutritional mode viz., photoautotrophic, photoheterotrophic and photomixotrophic on the biomass growth and lipid productivity of microalgae was studied. Experiments were designed and operated in biphasic mode i.e., growth phase (GP) followed by stress induced starvation phase (SP). Nutritional mode documented marked influence on biomass growth and subsequent lipid productivity. Mixotrophic mode of operation showed higher biomass growth (4.45 mg/ml) during growth phase while higher lipid productivity was observed with nitrogen deprived autotrophic mode (28.2%) followed by heterotrophic (26.1%) and mixotrophic (19.6%) operations. Relative increments in lipid productivities were noticed in SP operation from GP in mixotrophic operation (2.45) followed by autotrophic (2.2) and heterotrophic (2.14) mode of operations. Higher concentrations of chlorophyll b and presence of lipid accumulating species supported the lipid biosynthesis. Algal fatty acid composition varied with function of nutritional modes and depicted eighteen types of saturated (SFA) and unsaturated fatty acids (USFA) with wide fuel and food characteristics.

  18. Normativity in Fairy Tales: Scope, Range and Modes of Communication

    ERIC Educational Resources Information Center

    Hohr, Hansjörg

    2013-01-01

    The article studies in three steps how the fairy tale articulates its normative content and what the educational consequence of this kind of communication is. First, the articulation of normativity in fictional literature in general is discussed. Second, the specific mode in which the fairy tale articulates its normativity is studied according to…

  19. Accumulator

    NASA Technical Reports Server (NTRS)

    Fenwick, J. R.; Karigan, G. H. (Inventor)

    1977-01-01

    An accumulator particularly adapted for use in controlling the pressure of a stream of fluid in its liquid phase utilizing the fluid in its gaseous phase was designed. The accumulator is characterized by a shell defining a pressure chamber having an entry throat for a liquid and adapted to be connected in contiguous relation with a selected conduit having a stream of fluid flowing through the conduit in its liquid phase. A pressure and volume stabilization tube, including an array of pressure relief perforations is projected into the chamber with the perforations disposed adjacent to the entry throat for accommodating a discharge of the fluid in either gaseous or liquid phases, while a gas inlet and liquid to gas conversion system is provided, the chamber is connected with a source of the fluid for continuously pressuring the chamber for controlling the pressure of the stream of liquid.

  20. Particle simulations of mode conversion between slow mode and fast mode in lower hybrid range of frequencies

    SciTech Connect

    Jia, Guozhang; Xiang, Nong; Huang, Yueheng; Wang, Xueyi; Lin, Yu

    2016-01-15

    The propagation and mode conversion of lower hybrid waves in an inhomogeneous plasma are investigated by using the nonlinear δf algorithm in a two-dimensional particle-in-cell simulation code based on the gyrokinetic electron and fully kinetic ion (GeFi) scheme [Lin et al., Plasma Phys. Controlled Fusion 47, 657 (2005)]. The characteristics of the simulated waves, such as wavelength, frequency, phase, and group velocities, agree well with the linear theoretical analysis. It is shown that a significant reflection component emerges in the conversion process between the slow mode and the fast mode when the scale length of the density variation is comparable to the local wavelength. The dependences of the reflection coefficient on the scale length of the density variation are compared with the results based on the linear full wave model for cold plasmas. It is indicated that the mode conversion for the waves with a frequency of 2.45 GHz (ω ∼ 3ω{sub LH}, where ω{sub LH} represents the lower hybrid resonance) and within Tokamak relevant amplitudes can be well described in the linear scheme. As the frequency decreases, the modification due to the nonlinear term becomes important. For the low-frequency waves (ω ∼ 1.3ω{sub LH}), the generations of the high harmonic modes and sidebands through nonlinear mode-mode coupling provide new power channels and thus could reduce the reflection significantly.

  1. Particle simulations of mode conversion between slow mode and fast mode in lower hybrid range of frequencies

    NASA Astrophysics Data System (ADS)

    Jia, Guozhang; Xiang, Nong; Wang, Xueyi; Huang, Yueheng; Lin, Yu

    2016-01-01

    The propagation and mode conversion of lower hybrid waves in an inhomogeneous plasma are investigated by using the nonlinear δf algorithm in a two-dimensional particle-in-cell simulation code based on the gyrokinetic electron and fully kinetic ion (GeFi) scheme [Lin et al., Plasma Phys. Controlled Fusion 47, 657 (2005)]. The characteristics of the simulated waves, such as wavelength, frequency, phase, and group velocities, agree well with the linear theoretical analysis. It is shown that a significant reflection component emerges in the conversion process between the slow mode and the fast mode when the scale length of the density variation is comparable to the local wavelength. The dependences of the reflection coefficient on the scale length of the density variation are compared with the results based on the linear full wave model for cold plasmas. It is indicated that the mode conversion for the waves with a frequency of 2.45 GHz (ω ˜ 3ωLH, where ωLH represents the lower hybrid resonance) and within Tokamak relevant amplitudes can be well described in the linear scheme. As the frequency decreases, the modification due to the nonlinear term becomes important. For the low-frequency waves (ω ˜ 1.3ωLH), the generations of the high harmonic modes and sidebands through nonlinear mode-mode coupling provide new power channels and thus could reduce the reflection significantly.

  2. Coupled-mode sound propagation in a range-dependent, moving fluid

    NASA Astrophysics Data System (ADS)

    Godin, Oleg A.

    2002-05-01

    Full-field acoustic methods for current velocity inversion require accurate and efficient mathematical models of sound propagation in a range-dependent waveguide with flow. In this paper, an exact coupled-mode representation of the acoustic field is derived. To account for the physics of the problem, normal modes in a corresponding range-independent waveguide are chosen as the local basis. In the absence of currents, mode shape functions form a complete orthogonal basis. This property is heavily used in coupled-mode theories of sound propagation in motionless fluid. Unlike in the motionless case, however, vertical dependencies of acoustic pressure in individual normal modes are not orthogonal in the presence of currents. To overcome this difficulty, linearized equations of hydrodynamics are rewritten in terms of a state vector. Its five components are expressed in terms of acoustic pressure and particle displacement due to the wave. Orthogonality of the state vectors corresponding to individual normal modes is established. Coupled differential equations are derived for range-dependent mode amplitudes, leading to a remarkably simple result. The mode-coupling equations have the same form as those known for the motionless case, but of course the values of the mode-coupling coefficients differ as long as the range dependence of the flow velocity contributes to mode coupling in addition to the range dependence of sound speed and fluid density. The mode-coupling formulation is verified against known coupled-mode equations for certain limiting cases and an exact analytic solution of a benchmark problem.

  3. Microbial Community Composition of Polyhydroxyalkanoate-Accumulating Organisms in Full-Scale Wastewater Treatment Plants Operated in Fully Aerobic Mode

    PubMed Central

    Oshiki, Mamoru; Onuki, Motoharu; Satoh, Hiroyasu; Mino, Takashi

    2013-01-01

    The removal of biodegradable organic matter is one of the most important objectives in biological wastewater treatments. Polyhydroxyalkanoate (PHA)-accumulating organisms (PHAAOs) significantly contribute to the removal of biodegradable organic matter; however, their microbial community composition is mostly unknown. In the present study, the microbial community composition of PHAAOs was investigated at 8 full-scale wastewater treatment plants (WWTPs), operated in fully aerobic mode, by fluorescence in situ hybridization (FISH) analysis and post-FISH Nile blue A (NBA) staining techniques. Our results demonstrated that 1) PHAAOs were in the range of 11–18% in the total number of cells, and 2) the microbial community composition of PHAAOs was similar at the bacterial domain/phylum/class/order level among the 8 full-scale WWTPs, and dominant PHAAOs were members of the class Alphaproteobacteria and Betaproteobacteria. The microbial community composition of α- and β-proteobacterial PHAAOs was examined by 16S rRNA gene clone library analysis and further by applying a set of newly designed oligonucleotide probes targeting 16S rRNA gene sequences of α- or β-proteobacterial PHAAOs. The results demonstrated that the microbial community composition of PHAAOs differed in the class Alphaproteobacteria and Betaproteobacteria, which possibly resulted in a different PHA accumulation capacity among the WWTPs (8.5–38.2 mg-C g-VSS−1 h−1). The present study extended the knowledge of the microbial diversity of PHAAOs in full-scale WWTPs operated in fully aerobic mode. PMID:23257912

  4. Wide spectral range confocal microscope based on endlessly single-mode fiber.

    PubMed

    Hubbard, R; Ovchinnikov, Yu B; Hayes, J; Richardson, D J; Fu, Y J; Lin, S D; See, P; Sinclair, A G

    2010-08-30

    We report an endlessly single mode, fiber-optic confocal microscope, based on a large mode area photonic crystal fiber. The microscope confines a very broad spectral range of excitation and emission wavelengths to a single spatial mode in the fiber. Single-mode operation over an optical octave is feasible. At a magnification of 10 and λ = 900 nm, its resolution was measured to be 1.0 μm (lateral) and 2.5 μm (axial). The microscope's use is demonstrated by imaging single photons emitted by individual InAs quantum dots in a pillar microcavity.

  5. Observations of accumulation mode aerosol composition and soot carbon concentrations by means of a high-temperature volatility technique

    NASA Astrophysics Data System (ADS)

    Smith, Michael H.; O'Dowd, Colin D.

    1996-08-01

    A high-temperature volatility system has been deployed for the measurement of the composition and concentration of the accumulation mode aerosol (0.05 μm < r < 1 μm) within the atmospheric boundary layer. This instrumentation comprises a volatility system based around a Particle Measuring Systems ASASP-X optical particle counter, which was operated together with an aethalometer for the direct observation of soot carbon concentrations. By cycling the heater tube through a range of temperatures from near ambient to over 1000°C, size-differentiated information upon aerosol composition may be obtained. Furthermore, by careful selection of analysis temperatures, discrimination is possible between elemental carbon and the more volatile fractions of the soot carbon aerosol. Observations made over the North Sea near the Dutch coast and in the central United Kingdom are presented for differing environmental conditions with soot carbon concentrations ranging from about 100 to over 6000 ng m-3. For polluted conditions over the North Sea the volatility technique clearly showed the dominance of soot carbon particles over other aerosol components with a narrow carbon particle distribution of mode radius around 0.06 μm accounting for about 80% of all particles with radii below 0.1 μm. Under polluted conditions, only about 25% of the total soot carbon aerosol comprised elemental carbon (with the remainder consisting of more volatile material), whereas this proportion rose to around 50% in the lower carbon loadings found in a cleaner maritime air mass. The use of soot carbon loadings as a tracer of anthropogenic aerosol inputs to oceanic regions is explored on the basis of measurements from a NE Atlantic cruise.

  6. Silica uptake by Spartina-evidence of multiple modes of accumulation from salt marshes around the world.

    PubMed

    Carey, Joanna C; Fulweiler, Robinson W

    2014-01-01

    Silicon (Si) plays a critical role in plant functional ecology, protecting plants from multiple environmental stressors. While all terrestrial plants contain some Si, wetland grasses are frequently found to have the highest concentrations, although the mechanisms driving Si accumulation in wetland grasses remain in large part uncertain. For example, active Si accumulation is often assumed to be responsible for elevated Si concentrations found in wetland grasses. However, life stage and differences in Si availability in the surrounding environment also appear to be important variables controlling the Si concentrations of wetland grasses. Here we used original data from five North American salt marshes, as well as all known published literature values, to examine the primary drivers of Si accumulation in Spartina, a genus of prolific salt marsh grasses found worldwide. We found evidence of multiple modes of Si accumulation in Spartina, with passive accumulation observed in non-degraded marshes where Spartina was native, while rejective accumulation was found in regions where Spartina was invasive. Evidence of active accumulation was found in only one marsh where Spartina was native, but was also subjected to nutrient over-enrichment. We developed a conceptual model which hypothesizes that the mode of Si uptake by Spartina is dependent on local environmental factors and genetic origin, supporting the idea that plant species should be placed along a spectrum of Si accumulation. We hypothesize that Spartina exhibits previously unrecognized phenotypic plasticity with regard to Si accumulation, allowing these plants to respond to changes in marsh condition. These results provide new insight regarding how salt marsh ecosystems regulate Si exchange at the land-sea interface.

  7. Silica uptake by Spartina—evidence of multiple modes of accumulation from salt marshes around the world

    PubMed Central

    Carey, Joanna C.; Fulweiler, Robinson W.

    2014-01-01

    Silicon (Si) plays a critical role in plant functional ecology, protecting plants from multiple environmental stressors. While all terrestrial plants contain some Si, wetland grasses are frequently found to have the highest concentrations, although the mechanisms driving Si accumulation in wetland grasses remain in large part uncertain. For example, active Si accumulation is often assumed to be responsible for elevated Si concentrations found in wetland grasses. However, life stage and differences in Si availability in the surrounding environment also appear to be important variables controlling the Si concentrations of wetland grasses. Here we used original data from five North American salt marshes, as well as all known published literature values, to examine the primary drivers of Si accumulation in Spartina, a genus of prolific salt marsh grasses found worldwide. We found evidence of multiple modes of Si accumulation in Spartina, with passive accumulation observed in non-degraded marshes where Spartina was native, while rejective accumulation was found in regions where Spartina was invasive. Evidence of active accumulation was found in only one marsh where Spartina was native, but was also subjected to nutrient over-enrichment. We developed a conceptual model which hypothesizes that the mode of Si uptake by Spartina is dependent on local environmental factors and genetic origin, supporting the idea that plant species should be placed along a spectrum of Si accumulation. We hypothesize that Spartina exhibits previously unrecognized phenotypic plasticity with regard to Si accumulation, allowing these plants to respond to changes in marsh condition. These results provide new insight regarding how salt marsh ecosystems regulate Si exchange at the land-sea interface. PMID:24904599

  8. Modifications to JLab 12 GeV Refrigerator and Wide Range Mix Mode Performance Testing Results

    NASA Astrophysics Data System (ADS)

    Knudsen, P.; Ganni, V.; Hasan, N.; Dixon, K.; Norton, R.; Creel, J.

    2017-02-01

    Analysis of data obtained during the spring 2013 commissioning of the new 4.5 K refrigeration system at Jefferson Lab (JLab) for the 12 GeV upgrade indicated a wide capacity range with good efficiency and minimal operator interaction. Testing also showed that the refrigerator required higher liquid nitrogen (LN) consumption for its pre-cooler than anticipated by the design. This does not affect the capacity of the refrigerator, but it does result in an increased LN utility cost. During the summer of 2015 the modifications were implemented by the cold box manufacturer, according to a design similar to the JLab 12 GeV cold box specification. Subsequently, JLab recommissioned the cold box and performed extensive performance testing, ranging from 20% to 100% of the design maximum capacity, and in various modes of operation, ranging from pure refrigeration, pure liquefaction, half-and-half mix mode and at selected design modes using the Floating Pressure – Ganni Cycle. The testing demonstrated that the refrigerator system has a good and fairly constant performance over a wide capacity range and different modes of operation. It also demonstrated the modifications resulted in a LN consumption that met the design for the pure refrigeration mode (which is the most demanding) and was lower than the design for the nominal and maximum capacity modes. In addition, a pulsed-load test, similar to what is expected for cryogenic systems supporting fusion experiments, was conducted to observe the response using the Floating Pressure – Ganni Cycle, which was stable and robust. This paper will discuss the results and analysis of this testing pertaining to the LN consumption, the system efficiency over a wide range of capacity and different modes and the behaviour of the system to a pulsed load.

  9. Fractional activation of accumulation-mode particles in warm continental stratiform clouds

    SciTech Connect

    Gillani, N.V.; Daum, P.H.; Schwartz, S.E.; Leaitch, W.R.; Strapp, J.W.; Isaac, G.A.

    1991-07-01

    The degree of activation of accumulation-mode particles (AMP) in clouds has been studied using continuous (1 second average) aircraft measurements of the number concentrations of cloud droplets (N{sub cd}, 2 to 35 {mu}m diameter) and of unactivated AMP (N{sub amp}, 0.17 to 2.07 {mu}m diameter) in cloud interstitial air. The magnitude and spatial variation of the activated fraction (F) of all measured particles (defined as F {triple_bond} N{sub cd}/N{sub tot}, where N{sub tot} = N{sub cd} + N{sub amp}) are investigated, based on measurements made during ten aircraft flights in non-precipitating warm continental stratiform clouds near Syracuse NY in the fall of 1984. Based on instantaneous observations throughout the clouds, the spatial distribution of F was found to be quite nonuniform. In general, F was low in cloud edges and where total particle loading was high and/or cloud convective activity was low. In the interior of clouds, the value of F exceeded 0.9 for 36% of the data, but was below 0.6 for 28%. Factors influencing F the most were the total particle loading (N{sub tot}) and the thermal stability of the cloud layer. The dependence of F on N{sub tot} in cloud interior was characterized by two distinct regimes. For N{sub tot} < 600 cm{sup {minus}3}, F was generally close to unity and relatively insensitive to N{sub tot}. For N{sub tot} > 800 cm{sup {minus}3}, F tended to decrease with increasing N{sub tot}. This decrease was greatest in a stable stratus deck embedded in a warm moist airmass. The results suggest that, in warm continental stratiform clouds, the process of particle activation becomes nonlinear and self-limiting at high particle loading. The degree of this nonlinearity depends on cloud convective activity (thermal instability).

  10. Fractional activation of accumulation-mode particles in warm continental stratiform clouds

    SciTech Connect

    Gillani, N.V. Associates, Inc., St. Louis, MO ); Daum, P.H.; Schwartz, S.E. ); Leaitch, W.R.; Strapp, J.W.; Isaac, G.A. . Cloud Physics Research Div.)

    1991-07-01

    The degree of activation of accumulation-mode particles (AMP) in clouds has been studied using continuous (1 second average) aircraft measurements of the number concentrations of cloud droplets (N[sub cd], 2 to 35 [mu]m diameter) and of unactivated AMP (N[sub amp], 0.17 to 2.07 [mu]m diameter) in cloud interstitial air. The magnitude and spatial variation of the activated fraction (F) of all measured particles (defined as F [triple bond] N[sub cd]/N[sub tot], where N[sub tot] = N[sub cd] + N[sub amp]) are investigated, based on measurements made during ten aircraft flights in non-precipitating warm continental stratiform clouds near Syracuse NY in the fall of 1984. Based on instantaneous observations throughout the clouds, the spatial distribution of F was found to be quite nonuniform. In general, F was low in cloud edges and where total particle loading was high and/or cloud convective activity was low. In the interior of clouds, the value of F exceeded 0.9 for 36% of the data, but was below 0.6 for 28%. Factors influencing F the most were the total particle loading (N[sub tot]) and the thermal stability of the cloud layer. The dependence of F on N[sub tot] in cloud interior was characterized by two distinct regimes. For N[sub tot] < 600 cm[sup [minus]3], F was generally close to unity and relatively insensitive to N[sub tot]. For N[sub tot] > 800 cm[sup [minus]3], F tended to decrease with increasing N[sub tot]. This decrease was greatest in a stable stratus deck embedded in a warm moist airmass. The results suggest that, in warm continental stratiform clouds, the process of particle activation becomes nonlinear and self-limiting at high particle loading. The degree of this nonlinearity depends on cloud convective activity (thermal instability).

  11. Vibrational modes of GaN nanowires in the gigahertz range

    NASA Astrophysics Data System (ADS)

    Johnson, W. L.; Kim, S. A.; Geiss, R.; Flannery, C. M.; Bertness, K. A.; Heyliger, P. R.

    2012-12-01

    Brillouin-light-scattering measurements and finite-element modeling of vibrational spectra in the range of 5-40 GHz are presented for an array of monocrystalline GaN nanowires with hexagonal cross sections. Analysis of the spectra is substantially complicated by the presence of a distribution of nanowire diameters. The measurements and calculations reveal a variety of modes with simple flexural, higher-order flexural, approximately ‘plane-strain’, approximately longitudinal and torsional displacement patterns that are similar to the corresponding modes of isotropic cylinders. The largest peaks in the spectra with acoustic angular wavenumbers in the range of 4 to ˜15 μm-1 were determined to arise from modes with relatively large transverse displacements, consistent with inelastic light scattering arising predominantly from surface ripple. These dominant modes have finite frequencies in the limit of zero wavenumber, corresponding to transverse standing waves. At higher wavenumbers, the spectra provide evidence for increased scattering through elasto-optic coupling, especially with respect to the emergence of a peak from a mode analogous to the longitudinal guided modes of thin films. This manuscript is a contribution of the National Institute of Standards and Technology and is not subject to copyright in the United States.

  12. Pump power stability range of single-mode solid-state lasers with rod thermal lensing

    SciTech Connect

    De Silvestri, S.; La Porta, P.; Magni, V.

    1987-11-01

    The pump power stability range of solid-state laser resonators operating in the TEM/sub 00/ mode has been thoroughly investigated. It has been shown that, for a very general resonator containing intracavity optical systems, rod thermal lensing engenders a pump power stability range which is a characteristic parameter of laser material and pump cavity, but is independent of resonator configuration. Stability ranges have been calculated and critically discussed for Nd:YAG, Nd:Glasses, Nd:Cr:GSGG, and alexandrite. The independence of the pump power stability range from the resonator configuration has been experimentally demonstrated for a CW Nd:YAG laser.

  13. Carbon Nanotube Mode-Locked Thulium Fiber Laser With 200 nm Tuning Range.

    PubMed

    Meng, Yafei; Li, Yao; Xu, Yongbing; Wang, Fengqiu

    2017-03-21

    We demonstrated a mode-locked thulium/holmium (Tm/Ho) fiber laser continuously tunable across 200 nm (from 1860 nm to 2060 nm), which to the best of our knowledge represents the widest tuning range ever achieved for a passively mode-locked fiber laser oscillator. The combined use of a broadband carbon nanotube (CNT) saturable absorber and a diffraction grating mirror ensures ultra-broad tuning range, superb stability and repeatability, and makes the demonstrated laser a highly practical source for spectroscopy, imaging and optical communications. The laser emits <5 ps pulses with an optical spectral bandwidth of ∼3 nm across the full tuning range. Our results indicate that carbon nanotubes can be an excellent saturable absorber for achieving gain-bandwidth-limited tunable operation for 2 μm thulium fiber lasers.

  14. Carbon Nanotube Mode-Locked Thulium Fiber Laser With 200 nm Tuning Range

    NASA Astrophysics Data System (ADS)

    Meng, Yafei; Li, Yao; Xu, Yongbing; Wang, Fengqiu

    2017-03-01

    We demonstrated a mode-locked thulium/holmium (Tm/Ho) fiber laser continuously tunable across 200 nm (from 1860 nm to 2060 nm), which to the best of our knowledge represents the widest tuning range ever achieved for a passively mode-locked fiber laser oscillator. The combined use of a broadband carbon nanotube (CNT) saturable absorber and a diffraction grating mirror ensures ultra-broad tuning range, superb stability and repeatability, and makes the demonstrated laser a highly practical source for spectroscopy, imaging and optical communications. The laser emits <5 ps pulses with an optical spectral bandwidth of ∼3 nm across the full tuning range. Our results indicate that carbon nanotubes can be an excellent saturable absorber for achieving gain-bandwidth-limited tunable operation for 2 μm thulium fiber lasers.

  15. Carbon Nanotube Mode-Locked Thulium Fiber Laser With 200 nm Tuning Range

    PubMed Central

    Meng, Yafei; Li, Yao; Xu, Yongbing; Wang, Fengqiu

    2017-01-01

    We demonstrated a mode-locked thulium/holmium (Tm/Ho) fiber laser continuously tunable across 200 nm (from 1860 nm to 2060 nm), which to the best of our knowledge represents the widest tuning range ever achieved for a passively mode-locked fiber laser oscillator. The combined use of a broadband carbon nanotube (CNT) saturable absorber and a diffraction grating mirror ensures ultra-broad tuning range, superb stability and repeatability, and makes the demonstrated laser a highly practical source for spectroscopy, imaging and optical communications. The laser emits <5 ps pulses with an optical spectral bandwidth of ∼3 nm across the full tuning range. Our results indicate that carbon nanotubes can be an excellent saturable absorber for achieving gain-bandwidth-limited tunable operation for 2 μm thulium fiber lasers. PMID:28322327

  16. Multi-peak accumulation and coarse modes observed from AERONET retrieved aerosol volume size distribution in Beijing

    NASA Astrophysics Data System (ADS)

    Zhang, Ying; Li, Zhengqiang; Zhang, Yuhuan; Chen, Yu; Cuesta, Juan; Ma, Yan

    2016-08-01

    We present characteristic peaks of atmospheric columnar aerosol volume size distribution retrieved from the AErosol RObotic NETwork (AERONET) ground-based Sun-sky radiometer observation, and their correlations with aerosol optical properties and meteorological conditions in Beijing over 2013. The results show that the aerosol volume particle size distribution (VPSD) can be decomposed into up to four characteristic peaks, located in accumulation and coarse modes, respectively. The mean center radii of extra peaks in accumulation and coarse modes locate around 0.28 (±0.09) to 0.38 (±0.11) and 1.25 (±0.56) to 1.47 (±0.30) μm, respectively. The multi-peak size distributions are found in different aerosol loading conditions, with the mean aerosol optical depth (440 nm) of 0.58, 0.49, 1.18 and 1.04 for 2-, 3-I/II and 4-peak VPSD types, while the correspondingly mean relative humidity values are 58, 54, 72 and 67 %, respectively. The results also show the significant increase (from 0.25 to 0.40 μm) of the mean extra peak median radius in the accumulation mode for the 3-peak-II cases, which agrees with aerosol hygroscopic growth related to relative humidity and/or cloud or fog processing.

  17. [Effects of different nitrogen, phosphorous, and potassium fertilization modes on carbon- and nitrogen accumulation and allocation in rice plant].

    PubMed

    Feng, Lei; Tong, Cheng-li; Shi, Hui; Wu, Jin-shui; Chen, An-lei; Zhou, Ping

    2011-10-01

    Based on a 20-year field site-specific fertilization experiment in Taoyuan Experimental Station of Agriculture Ecosystems under Chinese Ecosystem Research Network (CERN), this paper studied the effects of different fertilization modes of N, P, and K on the accumulation and allocation of C and N in rice plant. The fertilization mode N-only showed the highest C and N contents (433 g kg(-1) and 18.9 g kg(-1), respectively) in rice grain, whereas the modes balanced fertilization of chemical N, P and K (NPK) and its combination with organic mature recycling (NPKC) showed the highest storage of C and N in rice plant. In treatments NPK and NPKC, the C storage in rice grain and in stem and leaf was 1960 kg hm(-2) and 2015 kg hm(-2), and 2002 kg hm(-2) and 2048 kg hm(-2), and the N storage in rice grain was 80.5 kg hm(-2) and 80.6 kg hm(-2), respectively. Treatment NPK had the highest N storage (59.3 kg hm(-2)) in stem and leaf. Balanced fertilization of chemical N, P, and K combined with organic manure recycling increased the accumulation of C and N in rice plant significantly. Comparing with applying N only, balanced fertilization of chemical N, P, and K was more favorable to the accumulation and allocation of C and N in rice plant during its growth period.

  18. Cramer-Rao lower bound on range error for LADARs with Geiger-mode avalanche photodiodes.

    PubMed

    Johnson, Steven E

    2010-08-20

    The Cramer-Rao lower bound (CRLB) on range error is calculated for laser detection and ranging (LADAR) systems using Geiger-mode avalanche photodiodes (GMAPDs) to detect reflected laser pulses. For the cases considered, the GMAPD range error CRLB is greater than the CRLB for a photon-counting device. It is also shown that the GMAPD range error CRLB is minimized when the mean energy in the received laser pulse is finite. Given typical LADAR system parameters, a Gaussian-envelope received pulse, and a noise detection rate of less than 4 MHz, the GMAPD range error CRLB is minimized when the quantum efficiency times the mean number of received laser pulse photons is between 2.2 and 2.3.

  19. Drift-insensitive distributed calibration of probe microscope scanner in nanometer range: Virtual mode

    NASA Astrophysics Data System (ADS)

    Lapshin, Rostislav V.

    2016-08-01

    A method of distributed calibration of a probe microscope scanner is suggested. The main idea consists in a search for a net of local calibration coefficients (LCCs) in the process of automatic measurement of a standard surface, whereby each point of the movement space of the scanner can be characterized by a unique set of scale factors. Feature-oriented scanning (FOS) methodology is used as a basis for implementation of the distributed calibration permitting to exclude in situ the negative influence of thermal drift, creep and hysteresis on the obtained results. Possessing the calibration database enables correcting in one procedure all the spatial systematic distortions caused by nonlinearity, nonorthogonality and spurious crosstalk couplings of the microscope scanner piezomanipulators. To provide high precision of spatial measurements in nanometer range, the calibration is carried out using natural standards - constants of crystal lattice. One of the useful modes of the developed calibration method is a virtual mode. In the virtual mode, instead of measurement of a real surface of the standard, the calibration program makes a surface image "measurement" of the standard, which was obtained earlier using conventional raster scanning. The application of the virtual mode permits simulation of the calibration process and detail analysis of raster distortions occurring in both conventional and counter surface scanning. Moreover, the mode allows to estimate the thermal drift and the creep velocities acting while surface scanning. Virtual calibration makes possible automatic characterization of a surface by the method of scanning probe microscopy (SPM).

  20. Are Ambient Ultrafine, Accumulation Mode, and Fine Particles Associated with Adverse Cardiac Responses in Patients Undergoing Cardiac Rehabilitation?

    PubMed Central

    Zareba, Wojciech; Beckett, William; Hopke, Philip K; Oakes, David; Frampton, Mark W; Bisognano, John; Chalupa, David; Bausch, Jan; O’Shea, Karen; Wang, Yungang; Utell, Mark J

    2012-01-01

    Background: Mechanisms underlying previously reported air pollution and cardiovascular (CV) morbidity associations remain poorly understood. Objectives: We examined associations between markers of pathways thought to underlie these air pollution and CV associations and ambient particle concentrations in postinfarction patients. Methods: We studied 76 patients, from June 2006 to November 2009, who participated in a 10-week cardiac rehabilitation program following a recent (within 3 months) myocardial infarction or unstable angina. Ambient ultrafine particle (UFP; 10–100 nm), accumulation mode particle (AMP; 100–500 nm), and fine particle concentrations (PM2.5; ≤ 2.5 μm in aerodynamic diameter) were monitored continuously. Continuous Holter electrocardiogram (ECG) recordings were made before and during supervised, graded, twice weekly, exercise sessions. A venous blood sample was collected and blood pressure was measured before sessions. Results: Using mixed effects models, we observed adverse changes in rMSSD [square root of the mean of the sum of the squared differences between adjacent normal-to-normal (NN) intervals], SDNN (standard deviation of all NN beat intervals), TpTe (time from peak to end of T-wave), heart rate turbulence, systolic and diastolic blood pressures, C-reactive protein, and fibrinogen associated with interquartile range increases in UFP, AMP, and PM2.5 at 1 or more lag times within the previous 5 days. Exposures were not associated with MeanNN, heart-rate–corrected QT interval duration (QTc), deceleration capacity, and white blood cell count was not associated with UFP, AMP, and PM2.5 at any lag time. Conclusions: In cardiac rehabilitation patients, particles were associated with subclinical decreases in parasympathetic modulation, prolongation of late repolarization duration, increased blood pressure, and systemic inflammation. It is possible that such changes could increase the risk of CV events in this susceptible population. PMID

  1. Potential effect of atmospheric warming on grapevine phenology and post-harvest heat accumulation across a range of climates

    NASA Astrophysics Data System (ADS)

    Hall, Andrew; Mathews, Adam J.; Holzapfel, Bruno P.

    2016-09-01

    Carbohydrates are accumulated within the perennial structure of grapevines when their production exceeds the requirements of reproduction and growth. The period between harvest and leaf-fall (the post-harvest period) is a key period for carbohydrate accumulation in relatively warmer grape-growing regions. The level of carbohydrate reserves available for utilisation in the following season has an important effect on canopy growth and yield potential and is therefore an important consideration in vineyard management. In a warming climate, the post-harvest period is lengthening and becoming warmer, evidenced through studies in wine regions worldwide that have correlated recent air temperature increases with changing grapevine phenology. Budbreak, flowering, veraison, and harvest have all been observed to be occurring earlier than in previous decades. Additionally, the final stage of the grapevine phenological cycle, leaf-fall, occurs later. This study explored the potential for increased post-harvest carbohydrate accumulation by modelling heat accumulation following harvest dates for the recent climate (1975-2004) and two warmer climate projections with mean temperature anomalies of +1.26 and +2.61 °C. Summaries of post-harvest heat accumulation between harvest and leaf-fall were produced for each of Australia's Geographical Indications (wine regions) to provide comparisons from the base temperatures to projected warmer conditions across a range of climates. The results indicate that for warmer conditions, all regions observe earlier occurring budbreak and harvest as well as increasing post-harvest growing degree days accumulation before leaf-fall. The level of increase varies depending upon starting climatic condition, with cooler regions experiencing the greatest change.

  2. Early Mode of Life and Hatchling Size in Cephalopod Molluscs: Influence on the Species Distributional Ranges

    PubMed Central

    Vidal, Erica A. G.; Fernández-Álvarez, Fernando Á.; Nabhitabhata, Jaruwat

    2016-01-01

    Cephalopods (nautiluses, cuttlefishes, squids and octopuses) exhibit direct development and display two major developmental modes: planktonic and benthic. Planktonic hatchlings are small and go through some degree of morphological changes during the planktonic phase, which can last from days to months, with ocean currents enhancing their dispersal capacity. Benthic hatchlings are usually large, miniature-like adults and have comparatively reduced dispersal potential. We examined the relationship between early developmental mode, hatchling size and species latitudinal distribution range of 110 species hatched in the laboratory, which represent 13% of the total number of live cephalopod species described to date. Results showed that species with planktonic hatchlings reach broader distributional ranges in comparison with species with benthic hatchlings. In addition, squids and octopods follow an inverse relationship between hatchling size and species latitudinal distribution. In both groups, species with smaller hatchlings have broader latitudinal distribution ranges. Thus, squid and octopod species with larger hatchlings have latitudinal distributions of comparatively minor extension. This pattern also emerges when all species are grouped by genus (n = 41), but was not detected for cuttlefishes, a group composed mainly of species with large and benthic hatchlings. However, when hatchling size was compared to adult size, it was observed that the smaller the hatchlings, the broader the latitudinal distributional range of the species for cuttlefishes, squids and octopuses. This was also valid for all cephalopod species with benthic hatchlings pooled together. Hatchling size and associated developmental mode and dispersal potential seem to be main influential factors in determining the distributional range of cephalopods. PMID:27829039

  3. Effects of range and mode on lifting capability and lifting time.

    PubMed

    Lee, Tzu-Hsien

    2012-01-01

    This study examined the effects of 3 lifting ranges and 3 lifting modes on maximum lifting capability and total lifting time. The results demonstrated that the maximum lifting capability for FK (from floor to knuckle height) was greater than that for KS (from knuckle height to shoulder height) or FS (from floor to shoulder height). Additionally, asymmetric lifting with initial trunk rotation decreased maximum lifting capability compared with symmetric lifting or asymmetric lifting with final trunk rotation. The difference in total lifting time between KS and FS was not significant, while FK increased total lifting time by ~20% compared with FS even though the travel distance was 50% shorter.

  4. Integrated photonic emitter with a wide switching range of orbital angular momentum modes

    PubMed Central

    Wang, Yu; Zhao, Peng; Feng, Xue; Xu, Yuntao; Cui, Kaiyu; Liu, Fang; Zhang, Wei; Huang, Yidong

    2016-01-01

    Due to the nature of infinite dimensionality, the orbital angular momentum (OAM) has been considered as a new degree of freedom of light and widely expanded the scopes of substantial optical applications such as optical telecommunication, quantum information, particle manipulation and imaging. In recent years, the integrated photonic OAM emitters have been actively investigated due to both compactness and tunability. Essentially, the number of available OAM modes by dynamic switching should be large enough so that the dimensionality of OAM could be explored as much as possible. In this work, an integrated photonic emitter with a wide switching range of OAM modes is theoretically developed, numerically simulated, and experimentally verified. The independence of the micro-ring cavity and the scattering unit provides the flexibility to design the device and optimize the performance. Specifically, the dynamic switching of nine OAM modes (l = −4 ~ 4) with azimuthal polarization has been demonstrated by electrically controlled thermo-optic effect. PMID:26936327

  5. Water filtration rate and infiltration/accumulation of low density lipoproteins in 3 different modes of endothelial/smooth muscle cell co-cultures.

    PubMed

    Ding, ZuFeng; Fan, YuBo; Deng, XiaoYan

    2009-11-01

    Using different endothelial/smooth muscle cell co-culture modes to simulate the intimal structure of blood vessels, the water filtration rate and the infiltration/accumulation of LDL of the cultured cell layers were studied. The three cell culture modes of the study were: (i) The endothelial cell monolayer (EC/Phi); (ii) endothelial cells directly co-cultured on the smooth muscle cell monolayer (EC-SMC); (iii) endothelial cells and smooth muscle cells cultured on different sides of a Millicell-CM membrane (EC/SMC). It was found that under the same condition, the water filtration rate was the lowest for the EC/SMC mode and the highest for the EC/Phi mode, while the infiltration/accumulation of DiI-LDLs was the lowest in the EC/Phi mode and the highest in the EC-SMC mode. It was also found that DiI-LDL infiltration/accumulation in the cultured cell layers increased with the increasing water filtration rate. The results from the in vitro model study therefore suggest that the infiltration/accumulation of the lipids within the arterial wall is positively correlated with concentration polarization of atherogenic lipids, and the integrity of the endothelium plays an important role in the penetration and accumulation of atherogenic lipids in blood vessel walls.

  6. Accumulation of Sb, Pb, Cu, Zn and Cd by various plants species on two different relocated military shooting range soils.

    PubMed

    Evangelou, Michael W H; Hockmann, Kerstin; Pokharel, Rasesh; Jakob, Alfred; Schulin, Rainer

    2012-10-15

    Annually, more than 400 t Pb and 10 t Sb enter Swiss soils at some 2000 military shooting ranges. After the decommission of military shooting ranges, heavily contaminated soils (>2000 mg kg(-1) Pb) are landfilled or processed by soil washing, whereas for soils with less contamination, alternate strategies are sought. Although the use of military shooting ranges for grazing in Switzerland is common practice, no assessment has been done about the uptake of Sb in plants and its subsequent potential intake by grazing animals. We determined the uptake of Sb, Pb, Cu, Zn and Cd in the aboveground biomass of nine plant species growing on a calcareous (Chur) and a weakly acidic (Losone) military shooting range soil in order to assess if grazing would be safe to employ on decommissioned military shooting ranges. The two soils did not differ in their total concentrations of Cu, Zn, Sb and Cd, they differed however in the total concentration of Pb. Additionally, their physical and chemical properties were significantly different. The accumulation of Zn, Cu, Cd and Pb in the shoots of all nine plant species remained below the Swiss tolerance values for fodder plants (150 mg kg(-1) Zn, 15-35 mg kg(-1) Cu, 40 mg kg(-1) Pb, and 1 mg kg(-1) Cd DW), with the only exception of Pb in Chenopodium album shoots which reached a concentration of 62 mg kg(-1) DW. Antimony concentrations were 1.5-2.6-fold higher in plants growing on the calcareous soil than on the weakly acidic soil. Considering Cu, Zn, Pb, Sb and Cd, all plants, with the exception C. album, would be suitable for grazing on similar shooting range soils.

  7. Effects of Trophic Modes, Carbon Sources, and Salinity on the Cell Growth and Lipid Accumulation of Tropic Ocean Oilgae Strain Desmodesmus sp. WC08.

    PubMed

    Zhao, Zhenyu; Ma, Shasha; Li, Ang; Liu, Pinghuai; Wang, Meng

    2016-10-01

    The effects of trophic modes, carbon sources, and salinity on the growth and lipid accumulation of a marine oilgae Desmodesmus sp. WC08 in different trophic cultures were assayed by single factor experiment based on the blue-green algae medium (BG-11). The results implied that biomass and lipid accumulation culture process were optimized depending on the tophic modes, sorts, and concentration of carbon sources and salinity in the cultivation. There was no significant difference in growth or lipid accumulation with Na2CO3 amendment or NaHCO3 amendment. However, Na2CO3 amendment did enhance the biomass and lipid accumulation to some extent. The highest Desmodesmus sp. WC08 biomass and lipid accumulation was achieved in the growth medium with photoautotrophic cultivation, 0.08 g L(-1) Na2CO3 amendment and 15 g L(-1) sea salt, respectively.

  8. Breakdown of long-range temporal dependence in default mode and attention networks during deep sleep

    PubMed Central

    Tagliazucchi, Enzo; von Wegner, Frederic; Morzelewski, Astrid; Brodbeck, Verena; Jahnke, Kolja; Laufs, Helmut

    2013-01-01

    The integration of segregated brain functional modules is a prerequisite for conscious awareness during wakeful rest. Here, we test the hypothesis that temporal integration, measured as long-term memory in the history of neural activity, is another important quality underlying conscious awareness. For this aim, we study the temporal memory of blood oxygen level-dependent signals across the human nonrapid eye movement sleep cycle. Results reveal that this property gradually decreases from wakefulness to deep nonrapid eye movement sleep and that such decreases affect areas identified with default mode and attention networks. Although blood oxygen level-dependent spontaneous fluctuations exhibit nontrivial spatial organization, even during deep sleep, they also display a decreased temporal complexity in specific brain regions. Conversely, this result suggests that long-range temporal dependence might be an attribute of the spontaneous conscious mentation performed during wakeful rest. PMID:24003146

  9. Joint Mode Selection and Resource Allocation for Cellular Controlled Short-Range Communication in OFDMA Networks

    NASA Astrophysics Data System (ADS)

    Deng, Hui; Tao, Xiaoming; Ge, Ning; Lu, Jianhua

    This letter studies cellular controlled short-range communication in OFDMA networks. The network needs to decide when to allow direct communication between a closely located device-to-device (D2D) pair instead of conveying data from one device to the other via the base station and when not to, in addition to subchannel and power allocation. Our goal is to maximize the total network throughput while guaranteeing the rate requirements of all users. For that purpose, we formulate an optimization problem subject to subchannel and power constraints. A scheme which combines a joint mode selection and subchannel allocation algorithm based on equal power allocation with a power reallocation scheme is proposed. Simulation results show that our proposed scheme can improve the network throughput and outage probability compared with other schemes.

  10. Ambulatory heart rate range predicts mode-specific mortality and hospitalisation in chronic heart failure

    PubMed Central

    Cubbon, Richard M; Ruff, Naomi; Groves, David; Eleuteri, Antonio; Denby, Christine; Kearney, Lorraine; Ali, Noman; Walker, Andrew M N; Jamil, Haqeel; Gierula, John; Gale, Chris P; Batin, Phillip D; Nolan, James; Shah, Ajay M; Fox, Keith A A; Sapsford, Robert J; Witte, Klaus K; Kearney, Mark T

    2016-01-01

    Objective We aimed to define the prognostic value of the heart rate range during a 24 h period in patients with chronic heart failure (CHF). Methods Prospective observational cohort study of 791 patients with CHF associated with left ventricular systolic dysfunction. Mode-specific mortality and hospitalisation were linked with ambulatory heart rate range (AHRR; calculated as maximum minus minimum heart rate using 24 h Holter monitor data, including paced and non-sinus complexes) in univariate and multivariate analyses. Findings were then corroborated in a validation cohort of 408 patients with CHF with preserved or reduced left ventricular ejection fraction. Results After a mean 4.1 years of follow-up, increasing AHRR was associated with reduced risk of all-cause, sudden, non-cardiovascular and progressive heart failure death in univariate analyses. After accounting for characteristics that differed between groups above and below median AHRR using multivariate analysis, AHRR remained strongly associated with all-cause mortality (HR 0.991/bpm increase in AHRR (95% CI 0.999 to 0.982); p=0.046). AHRR was not associated with the risk of any non-elective hospitalisation, but was associated with heart-failure-related hospitalisation. AHRR was modestly associated with the SD of normal-to-normal beats (R2=0.2; p<0.001) and with peak exercise-test heart rate (R2=0.33; p<0.001). Analysis of the validation cohort revealed AHRR to be associated with all-cause and mode-specific death as described in the derivation cohort. Conclusions AHRR is a novel and readily available prognosticator in patients with CHF, which may reflect autonomic tone and exercise capacity. PMID:26674986

  11. A uniform doping ultra-thin SOI LDMOS with accumulation-mode extended gate and back-side etching technology

    NASA Astrophysics Data System (ADS)

    Yan-Hui, Zhang; Jie, Wei; Chao, Yin; Qiao, Tan; Jian-Ping, Liu; Peng-Cheng, Li; Xiao-Rong, Luo

    2016-02-01

    A uniform doping ultra-thin silicon-on-insulator (SOI) lateral-double-diffused metal-oxide-semiconductor (LDMOS) with low specific on-resistance (Ron,sp) and high breakdown voltage (BV) is proposed and its mechanism is investigated. The proposed LDMOS features an accumulation-mode extended gate (AG) and back-side etching (BE). The extended gate consists of a P- region and two diodes in series. In the on-state with VGD > 0, an electron accumulation layer is formed along the drift region surface under the AG. It provides an ultra-low resistance current path along the whole drift region surface and thus the novel device obtains a low temperature distribution. The Ron,sp is nearly independent of the doping concentration of the drift region. In the off-state, the AG not only modulates the surface electric field distribution and improves the BV, but also brings in a charge compensation effect to further reduce the Ron,sp. Moreover, the BE avoids vertical premature breakdown to obtain high BV and allows a uniform doping in the drift region, which avoids the variable lateral doping (VLD) and the “hot-spot” caused by the VLD. Compared with the VLD SOI LDMOS, the proposed device simultaneously reduces the Ron,sp by 70.2% and increases the BV from 776 V to 818 V. Project supported by the National Natural Science Foundation of China (Grant Nos. 61176069 and 61376079).

  12. Synchronized growth and neutral lipid accumulation in Chlorella sorokiniana FC6 IITG under continuous mode of operation.

    PubMed

    Kumar, Vikram; Muthuraj, Muthusivaramapandian; Palabhanvi, Basavaraj; Das, Debasish

    2016-01-01

    Synchronized growth and neutral lipid accumulation with high lipid productivity under mixotrophic growth of the strain Chlorella sorokiniana FC6 IITG was achieved via manipulation of substrates feeding mode and supplementation of lipid elicitors in the growth medium. Screening and optimization of lipid elicitors resulted in lipid productivity of 110.59mgL(-1)day(-1) under the combined effect of lipid inducers sodium acetate and sodium chloride. Fed-batch cultivation of the strain in bioreactor with intermittent feeding of limiting nutrients and lipid inducer resulted in maximum biomass and lipid productivity of 2.08 and 0.97gL(-1)day(-1) respectively. Further, continuous production of biomass with concomitant lipid accumulation was demonstrated via continuous feeding of BG11 media supplemented with lipid inducers sodium acetate and sodium chloride. The improved biomass and lipid productivity in chemostat was found to be 2.81 and 1.27gL(-1)day(-1) respectively operated at a dilution rate of 0.54day(-1).

  13. A comparative study of the effect of some nutritional medicinal plants effect on lead accumulation in the liver following different modes of administration

    PubMed Central

    Nwokocha, Chukwuemeka; Younger-Coleman, Novie; Nwokocha, Magdalene; Owu, Daniel; Iwuala, Moses

    2014-01-01

    Context and Objectives: Lead (Pb) toxicity leads to cell damage in many organs of the body. Using different treatment interventions and modes of administration we comparatively examined the protective ability of some medicinal plants on liver Pb accumulation. Materials and Methods: Rats were fed on either 7% w/w Zingiber officinale, 7% w/w Allium sativum, 10% w/w Lycopersicon esculentum, 5%, w/w Garcinia kola (all in rat chow), while Pb (100 ppm) was given in drinking water. The additives were administered together with (mode 1), a week after exposure to (mode 2) or a week before metal exposure to (mode 3) the metal for a period of 6 weeks. The metal accumulations in the liver were determined using atomic absorption spectrometry and compared using analysis of variance. Results: Some additives significantly (P < 0.05) reduced, while others enhanced Pb accumulation. Mode 2 yielded the highest mean % protection and mode 3 the lowest, no significant interaction between modes of administration and time of measurement in their relationships to percentage protection, but there was statistically significant (P < 0.05) interaction between modes of administration and additive used in their relationships to percentage protection. Conclusion: Protective effects of medicinal plants are varied and depend on the nature of lead exposure. PMID:25276068

  14. Ion beam generated modes in the lower hybrid frequency range in a laboratory magnetoplasma

    NASA Astrophysics Data System (ADS)

    van Compernolle, Bart; Tripathi, Shreekrishna Kp; Gekelman, Walter; Pribyl, Patrick; Colestock, Patrick

    2012-10-01

    The interaction of a fast ion beam with a low β plasma has been studied in the laboratory. Experiments were performed at the LArge Plasma Device (LAPD) at UCLA. The experiments were done in a Helium plasma (n ˜10^12 cm-3, B0 = 1000 G - 1800 G, fpe/fce˜1 - 5, Te= 0.25 eV, vtevA). The ion beam is a Helium beam with energies ranging from 5 keV to 18 keV. The fast ion velocity is on the order of the Alfv'en velocity. The beam is injected from the end of the machine, and spirals down the linear device. Waves were observed below fci in the shear Alfv'en wave regime, and in a broad spectrum above fci in the lower hybrid frequency range, the focus of this paper. The wave spectra have distinct peaks close to ion cyclotron harmonics, extending out to the 100th harmonic in some cases. The wave generation was studied for various plasma parameters, as well as for different beam energies and pitch angles. The waves were measured with 3-axis electric and magnetic probes. Detailed measurements of the perpendicular mode structure will be shown. Langmuir probes were used to measure density and temperature evolution due to the beam-plasma interaction. Retarding field energy analyzers captured the ion beam profiles.

  15. Ion beam generated modes in the lower hybrid frequency range in a laboratory magnetoplasma

    NASA Astrophysics Data System (ADS)

    van Compernolle, Bart; Tripathi, Shreekrishna; Gekelman, Walter; Pribyl, Patrick

    2013-10-01

    The interaction of a fast ion beam with a low β plasma has been studied in the laboratory. Experiments were performed at the LArge Plasma Device (LAPD) at UCLA. The experiments were done in a Helium plasma (n ~=1012cm-3 , B0 = 1000 G - 1800 G, fpe /fce ~= 1 - 5 , Te ~= 4eV , vte <ranging from 5 keV to 18 keV. The fast ion velocity is on the order of the Alfvén velocity. The beam is injected from the end of the machine, and spirals down the linear device. Waves were observed below fci in the shear Alfvén wave regime, and in a broad spectrum above fci in the lower hybrid frequency range. The wave generation was studied for various plasma parameters, as well as for different beam energies and pitch angles. The waves were measured with 3-axis electric and magnetic probes. Detailed measurements of the 2D perpendicular mode structure will be shown. Progress on a theoretical framework of the wave generation by the ion beam will be presented along with comparisons to the measured wave properties. The work was performed at the LArge Plasma Device at the Basic Plasma Science Facility (BaPSF) at UCLA, funded by DOE/NSF.

  16. Processes and rates of sediment and wood accumulation in headwater streams of the Oregon Coast Range, USA

    USGS Publications Warehouse

    May, Christine L.; Gresswell, Robert E.

    2003-01-01

    Channels that have been scoured to bedrock by debris flows provide unique opportunities to calculate the rate of sediment and wood accumulation in low-order streams, to understand the temporal succession of channel morphology following disturbance, and to make inferences about processes associated with input and transport of sediment. Dendrochronology was used to estimate the time since the previous debris flow and the time since the last stand-replacement fire in unlogged basins in the central Coast Range of Oregon. Debris flow activity increased 42 per cent above the background rate in the decades immediately following the last wildfire. Changes in wood and sediment storage were quantified for 13 streams that ranged from 4 to 144 years since the previous debris flow. The volume of wood and sediment in the channel, and the length of channel with exposed bedrock, were strongly correlated with the time since the previous debris flow. Wood increased the storage capacity of the channel and trapped the majority of the sediment in these steep headwater streams. In the absence of wood, channels that have been scoured to bedrock by a debris flow may lack the capacity to store sediment and could persist in a bedrock state for an extended period of time. With an adequate supply of wood, low-order channels have the potential of storing large volumes of sediment in the interval between debris flows and can function as one of the dominant storage reservoirs for sediment in mountainous terrain.

  17. Geomorphic controls on mercury accumulation in soils from a historically mined watershed, Central California Coast Range, USA

    USGS Publications Warehouse

    Holloway, J.M.; Goldhaber, M.B.; Morrison, J.M.

    2009-01-01

    Historic Hg mining in the Cache Creek watershed in the Central California Coast Range has contributed to the downstream transport of Hg to the San Francisco Bay-Delta. Different aspects of Hg mobilization in soils, including pedogenesis, fluvial redistribution of sediment, volatilization and eolian transport were considered. The greatest soil concentrations (>30 mg Hg kg-1) in Cache Creek are associated with mineralized serpentinite, the host rock for Hg deposits. Upland soils with non-mineralized serpentine and sedimentary parent material also had elevated concentrations (0.9-3.7 mg Hg kg-1) relative to the average concentration in the region and throughout the conterminous United States (0.06 mg kg-1). Erosion of soil and destabilized rock and mobilization of tailings and calcines into surrounding streams have contributed to Hg-rich alluvial soil forming in wetlands and floodplains. The concentration of Hg in floodplain sediment shows sediment dispersion from low-order catchments (5.6-9.6 mg Hg kg-1 in Sulphur Creek; 0.5-61 mg Hg kg-1 in Davis Creek) to Cache Creek (0.1-0.4 mg Hg kg-1). These sediments, deposited onto the floodplain during high-flow storm events, yield elevated Hg concentrations (0.2-55 mg Hg kg-1) in alluvial soils in upland watersheds. Alluvial soils within the Cache Creek watershed accumulate Hg from upstream mining areas, with concentrations between 0.06 and 0.22 mg Hg kg-1 measured in soils ~90 km downstream from Hg mining areas. Alluvial soils have accumulated Hg released through historic mining activities, remobilizing this Hg to streams as the soils erode.

  18. Accumulation of lead (Pb) in brown trout (Salmo trutta) from a lake downstream a former shooting range.

    PubMed

    Mariussen, Espen; Heier, Lene Sørlie; Teien, Hans Christian; Pettersen, Marit Nandrup; Holth, Tor Fredrik; Salbu, Brit; Rosseland, Bjørn Olav

    2017-01-01

    An environmental survey was performed in Lake Kyrtjønn, a small lake within an abandoned shooting range in the south of Norway. In Lake Kyrtjønn the total water concentrations of Pb (14µg/L), Cu (6.1µg/L) and Sb (1.3µg/L) were elevated compared to the nearby reference Lake Stitjønn, where the total concentrations of Pb, Cu and Sb were 0.76, 1.8 and 0.12µg/L, respectively. Brown trout (Salmo trutta) from Lake Kyrtjønn had very high levels of Pb in bone (104mg/kg w.w.), kidney (161mg/kg w.w.) and the gills (137mg/kg d.w), and a strong inhibition of the ALA-D enzyme activity were observed in the blood (24% of control). Dry fertilized brown trout eggs were placed in the small outlet streams from Lake Kyrtjønn and the reference lake for 6 months, and the concentrations of Pb and Cu in eggs from the Lake Kyrtjønn stream were significantly higher than in eggs from the reference. More than 90% of Pb accumulated in the egg shell, whereas more than 80% of the Cu and Zn accumulated in the egg interior. Pb in the lake sediments was elevated in the upper 2-5cm layer (410-2700mg/kg d.w), and was predominantly associated with redox sensitive fractions (e.g., organic materials, hydroxides) indicating low potential mobility and bioavailability of the deposited Pb. Only minor amounts of Cu and Sb were deposited in the sediments. The present work showed that the adult brown trout, as well as fertilized eggs and alevins, may be subjected to increased stress due to chronic exposure to Pb, whereas exposure to Cu, Zn and Sb were of less importance.

  19. Ion beam generated modes in the lower hybrid frequency range in a laboratory magnetoplasma

    NASA Astrophysics Data System (ADS)

    Van Compernolle, B.; Tripathi, S.; Gekelman, W. N.; Colestock, P. L.; Pribyl, P.

    2012-12-01

    The generation of waves by ion ring distributions is of great importance in many instances in space plasmas. They occur naturally in the magnetosphere through the interaction with substorms, or they can be man-made in ionospheric experiments by photo-ionization of neutral atoms injected perpendicular to the earth's magnetic field. The interaction of a fast ion beam with a low β plasma has been studied in the laboratory. Experiments were performed at the LArge Plasma Device (LAPD) at UCLA. The experiments were done in a Helium plasma (n ≃ 1012 \\ cm-3, B0 = 1000 G - 1800 G, fpe}/f{ce ≃ 1 - 5, Te = 0.25\\ eV, vte ≤ vA). The ion beam \\cite{Tripathi_ionbeam} is a Helium beam with energies ranging from 5 keV to 18 keV. The fast ion velocity is on the order of the Alfvén velocity. The beam is injected from the end of the machine, and spirals down the linear device. Waves were observed below fci in the shear Alfvén wave regime, and in a broad spectrum above fci in the lower hybrid frequency range, the focus of this paper. The wave spectra have distinct peaks close to ion cyclotron harmonics, extending out to the 100th harmonic in some cases. The wave generation was studied for various magnetic fields and background plasma densities, as well as for different beam energies and pitch angles. The waves were measured with 3-axis electric and magnetic probes. Detailed measurements of the perpendicular mode structure will be shown. Langmuir probes were used to measure density and temperature evolution due to the beam-plasma interaction. Retarding field energy analyzers captured the ion beam profiles. The work was performed at the LArge Plasma Device at the Basic Plasma Science Facility (BaPSF) at UCLA, funded by DOE/NSF.

  20. Second-order overtone and combination Raman modes of graphene layers in the range of 1690-2150 cm(-1).

    PubMed

    Cong, Chunxiao; Yu, Ting; Saito, Riichiro; Dresselhaus, Gene F; Dresselhaus, Mildred S

    2011-03-22

    Though graphene has been intensively studied by Raman spectroscopy, in this letter, we report a study of the second-order overtone and combination Raman modes in a mostly unexplored frequency range of 1690-2150 cm(-1) in nonsuspended commensurate (AB-stacked), incommensurate (folded) and suspended graphene layers. On the basis of the double resonance theory, four dominant modes in this range have been assigned to (i) the second order out-of-plane transverse mode (2oTO or M band), (ii) the combinational modes of in-plane transverse acoustic mode and longitudinal optical mode (iTA+LO), (iii) in-plane transverse optical mode and longitudinal acoustic mode (iTO+LA), and (iv) longitudinal optical mode and longitudinal acoustic mode (LO+LA). Differing from AB-stacked bilayer graphene or few layer graphene, single layer graphene shows the disappearance of the M band. Systematic analysis reveals that interlayer interaction is essential for the presence (or absence) of the M band, whereas the substrate has no effect on the presence (or absence) of the M band. Dispersive behaviors of these "new" Raman modes in graphene have been probed by laser excitation energy-dependent Raman spectroscopy. It is found that the appearance of the M band strictly depends on the AB stacking, which could be used as a fingerprint for AB-stacked bilayer graphene. This work expands upon the unique and powerful abilities of Raman spectroscopy to study graphene and provides another effective way to probe phonon dispersion, electron-phonon coupling, and to exploit the electronic band structure of graphene layers.

  1. Statistics of Fourier modes of velocity and vorticity in turbulent flows: intermittency and long-range correlations.

    PubMed

    Chevillard, L; Mazellier, N; Poulain, C; Gagne, Y; Baudet, C

    2005-11-11

    We perform a statistical analysis of experimental fully developed turbulence longitudinal velocity data in the Fourier space. We address the controversial issue of statistical intermittency of spatial Fourier modes by acting on the finite spectral resolution. We derive a link between velocity structure functions and the flatness of Fourier modes thanks to cascade models. Similar statistical behaviors are recovered in the analysis of spatial Fourier modes of vorticity obtained in an acoustic scattering experiment. We conclude that vorticity is long-range correlated and found more intermittent than longitudinal velocity.

  2. Extended Constant Power Speed Range of the Brushless DC Motor Through Dual Mode Inverter Control

    SciTech Connect

    Lawler, J.S.

    2000-06-23

    The trapezoidal back electromotive force (emf) brushless direct current (dc) motor (BDCM) with surface-mounted magnets has high-power density and efficiency especially when rare-earth magnet materials are used. Traction applications, such as electric vehicles, could benefit significantly from the use of such motors. Unfortunately, a practical means for driving the motor over a constant power speed ratio (CPSR) of 5:1 or more has not yet been developed. A key feature of these motors is that they have low internal inductance. The phase advance method is effective in controlling the motor power over such a speed range, but the current at high speed may be several times greater than that required at the base speed. The increase in current during high-speed operation is due to the low motor inductance and the action of the bypass diodes of the inverter. The use of such a control would require increased current rating of the inverter semiconductors and additional cooling for the inverter, where the conduction losses increase proportionally with current, and especially for the motor, where the losses increase with the square of the current. The high current problems of phase advance can be mitigated by adding series inductance; however, this reduces power density, requires significant increase in supply voltage, and leaves the CPSR performance of the system highly sensitive to variations in the available voltage. A new inverter topology and control scheme has been developed that can drive low-inductance BDCMs over the CPSR that would be required in electric vehicle applications. This new controller is called the dual-mode inverter control (DMIC). It is shown that the BDCM has an infinite CPSR when it is driven by the DMIC.

  3. Square-wave pulse with ultra-wide tuning range in a passively mode-locked fiber laser.

    PubMed

    Zhang, Xianming; Gu, Chun; Chen, Guoliang; Sun, Biao; Xu, Lixin; Wang, Anting; Ming, Hai

    2012-04-15

    We report the generation of ultrawide tunable square-wave pulse in an erbium-doped mode-locked fiber laser. The pulse width can be tuned in an ultrawide range of more than 1700 ns by simply increasing the pump power. The pulse-width tuning is 5.1 ns/mW. To the best of our knowledge, this is the widest pulse-width tuning range of any square-wave pulse in an all-fiber passively mode-locked fiber laser. Experimental results show that the fiber nonlinearity plays an important role in the tuning range of the output pulse width. The high nonlinearity helps to increase the tuning range of the pulse width.

  4. 100-Gbit/s PDM-QPSK coherent receiver with wide dynamic range and excellent common-mode rejection ratio.

    PubMed

    Murata, Koichi; Saida, Takashi; Sano, Kimikazu; Ogawa, Ikuo; Fukuyama, Hiroyuki; Kasahara, Ryoichi; Muramoto, Yoshifumi; Nosaka, Hideyuki; Tsunashima, Satoshi; Mizuno, Takayuki; Tanobe, Hiromasa; Hattori, Kuninori; Yoshimatsu, Toshihide; Kawakami, Hiroto; Yoshida, Eiji

    2011-12-12

    We report the design and fabrication of a hybrid-integration-type coherent receiver. We optimize the receiver building blocks, and achieve a -25-dB common-mode rejection ratio and a 20-dB signal input power dynamic range.

  5. Communication system features dual mode range acquisition plus time delay measurement

    NASA Technical Reports Server (NTRS)

    Atwood, S. W.; Kline, A. W., Jr.; Welter, N. E.

    1968-01-01

    Communication system combines range acquisition system and time measurement system for tracking high velocity aircraft and spacecraft. The range acquisition system uses a pseudonoise code to determine range and the time measurement system reduces uncontrolled phase variations in the demodulated signal.

  6. Blade tip clearance measurement of the turbine engines based on a multi-mode fiber coupled laser ranging system

    SciTech Connect

    Guo, Haotian; Duan, Fajie; Wu, Guoxiu; Zhang, Jilong

    2014-11-15

    The blade tip clearance is a parameter of great importance to guarantee the efficiency and safety of the turbine engines. In this article, a laser ranging system designed for blade tip clearance measurement is presented. Multi-mode fiber is utilized for optical transmission to guarantee that enough optical power is received by the sensor probe. The model of the tiny sensor probe is presented. The error brought by the optical path difference of different modes of the fiber is estimated and the length of the fiber is limited to reduce this error. The measurement range in which the optical power received by the probe remains essentially unchanged is analyzed. Calibration experiments and dynamic experiments are conducted. The results of the calibration experiments indicate that the resolution of the system is about 0.02 mm and the range of the system is about 9 mm.

  7. Large tensor mode, field range bound and consistency in generalized G-inflation

    SciTech Connect

    Kunimitsu, Taro; Suyama, Teruaki; Watanabe, Yuki; Yokoyama, Jun'ichi E-mail: suyama@resceu.s.u-tokyo.ac.jp E-mail: yokoyama@resceu.s.u-tokyo.ac.jp

    2015-08-01

    We systematically show that in potential driven generalized G-inflation models, quantum corrections coming from new physics at the strong coupling scale can be avoided, while producing observable tensor modes. The effective action can be approximated by the tree level action, and as a result, these models are internally consistent, despite the fact that we introduced new mass scales below the energy scale of inflation. Although observable tensor modes are produced with sub-strong coupling scale field excursions, this is not an evasion of the Lyth bound, since the models include higher-derivative non-canonical kinetic terms, and effective rescaling of the field would result in super-Planckian field excursions. We argue that the enhanced kinetic term of the inflaton screens the interactions with other fields, keeping the system weakly coupled during inflation.

  8. Comment on "Mode Conversion of Waves In The Ion-Cyclotron Frequency Range in Magnetospheric Plasmas"

    SciTech Connect

    Kim, Eun; Johnson, J. R.

    2014-02-01

    Recently, Kazakov and Fulop [1] studied mode conversion (MC) at the ion-ion hybrid (IIH) resonance in planetary magnetospheric plasmas by simplifying the dispersion relation of the fast wave (FW) modes to describe a cutoff-resonance (CR) pair near the IIH resonance, which can be reduced to a Budden problem. They suggested that when the IIH resonance frequency (ωS) approaches the crossover frequency (ωcr), and the parallel wavenumber (k∥) is close to the critical wavenumber k* ∥(ωS = ωcr), MC can be efficient for arbitrary heavy ion density ratios. In this Comment, we argue that (a) the FW dispersion relation cannot be simplified to the CR pair especially near ωcr because in many parameter regimes there is a cutoff-resonance-cutoff (CRC) triplet that completely changes the wave absorption; and (b) the maximum MC efficiency does not always occur near k∥ ≈ k*∥∥.

  9. Long-range optical binding in a hollow-core photonic crystal fiber using higher order modes

    NASA Astrophysics Data System (ADS)

    Bykov, Dmitry S.; Zeltner, Richard; Euser, Tijmen G.; Xie, Shangran; Russell, Philip St. J.

    2016-09-01

    We report long-range optical binding of multiple polystyrene nanoparticles (100-600 nm in diameter) at fixed interparticle distances that match multiples of the half-beat-lengths between the lowest order modes of a hollow-core photonic crystal fiber. Analysis suggests that each nanoparticle converts the incoming optical mode into a superposition of co-propagating modes, within the beat pattern of which further particles can become trapped. Strikingly, the entire particle arrangement can be moved over a distance of several cm, without changing the inter-particle spacing, by altering the ratio of backward-to-forward optical power. Potential applications are in multi-dimensional nanoparticle-based quantum optomechanical systems.

  10. Variational derivation of the dispersion relation of kinetic coherent modes in the acoustic frequency range in tokamaks

    SciTech Connect

    Nguyen, C.; Garbet, X.; Smolyakov, A. I.

    2008-11-15

    In the present paper, we compare two modes with frequencies belonging to the acoustic frequency range: the geodesic acoustic mode (GAM) and the Beta Alfven eigenmode (BAE). For this, a variational gyrokinetic energy principle coupled to a Fourier sidebands expansion is developed. High order finite Larmor radius and finite orbit width effects are kept. Their impact on the mode structures and on the Alfven spectrum is calculated and discussed. We show that in a local analysis, the degeneracy of the electrostatic GAM and the BAE dispersion relations is verified to a high order and based in particular on a local poloidal symmetry of the two modes. When a more global point of view is taken, and the full radial structures of the modes are computed, differences appear. The BAE structure is shown to have an enforced localization, and to possibly connect to a large magnetohydrodynamic structure. On the contrary, the GAM is seen to have a wavelike, nonlocalized structure, as long as standard slowly varying monotonic profiles are considered.

  11. Impact of major and minor mode on EEG frequency range activities of music processing as a function of expertise.

    PubMed

    Jenni, Raoul; Oechslin, Mathias S; James, Clara E

    2017-04-24

    Processing western tonal music may yield distinct brain responses depending on the mode of the musical compositions. Although subjective feelings in response to major and minor mode are well described, the underlying brain mechanisms and their development with increasing expertise have not been thoroughly examined. Using high-density electroencephalography, the present study investigated neuronal activities in the frequency domain in response to polyphone musical compositions in major and minor mode in non-musicians, amateurs and experts. During active listening decrease of theta- and gamma-frequency range activities occurred with increasing expertise in right posterior regions, possibly reflecting enhanced processing efficiency. Moreover, minor and major compositions distinctively modulated synchronization of neuronal activities in high frequency ranges (beta and gamma) in frontal regions, with increased activity in response to minor compositions in musicians and in experts in particular. These results suggest that high-frequency electroencephalographic (EEG) activities carry information about musical mode, showing gradual increase of processing efficiency and sensitivity with musical expertise.

  12. Diagnostics for Wave Mode Identification in the Dissipation Range of Solar Wind Turbulence: Kinetic Alfven Waves versus Whistlers

    NASA Astrophysics Data System (ADS)

    Salem, C. S.; Sundkvist, D. J.; Bale, S.; Howes, G. G.; Chaston, C. C.

    2011-12-01

    We analyze the effect of Doppler shift on Kinetic Alfven Waves (KAW) as well as compressional proton Whistler Waves at frequencies above the local ion cyclotron frequency into the so-called dissipation range of solar wind turbulence (0.1 < f/fci < 10). Prior studies have shown that wave modes in this frequency range become dispersive and are consistent with Kinetic Alfven Waves (KAW) under the assumption that Taylor's hypothesis is still valid at those frequencies. However, the proton whistler is another possible wave mode in the solar wind in this frequency range. The temporal fluctuations of this mode combined with a slight Doppler shift can lead to the same apparent properties in the spacecraft (s/c) frame as strongly Doppler-shifted KAW. First, we present a different approach to resolve this long-standing question regarding the nature of the electromagnetic fluctuations in the dissipation range of solar wind turbulence. Specifically, we determine, both analytically and numerically, the dispersive properties of the KAW and the whistler wave modes and estimate the electric to magnetic field (E/B) ratio in the plasma and the s/c frame to make direct comparisons with s/c data. We discuss the predicted, observable, parameters of both KAW and whistlers in the plasma and s/c frames. We show that the properties of both KAW and whistlers appear to be similar in the s/c frame, yet there are quantifiable differences that one can use to distinguish between both wave modes. Those differences are discussed. Finally, we revisit Cluster electric field and magnetic field data in the solar wind using this technique. We focus our analysis on several low-beta (β < 1) ambient solar wind intervals. We compare the predicted parameters from our technique to the data directly in the s/c frame, without the use of Taylor's hypothesis. We propose this technique as an efficient diagnostics for wave-mode identification in the dissipation (or dispersion) range of solar wind turbulence.

  13. Passive mode locking at harmonics of the free spectral range of the intracavity filter in a fiber ring laser.

    PubMed

    Zhang, Shumin; Lu, Fuyun; Dong, Xinyong; Shum, Ping; Yang, Xiufeng; Zhou, Xiaoqun; Gong, Yandong; Lu, Chao

    2005-11-01

    We report the passive mode-locking at harmonics of the free spectral range (FSR) of the intracavity multi-channel filter in a fiber ring laser. The laser uses a sampled fiber Bragg grating (SFBG) with a free spectral range (FSR) of 0.8 nm, or 99 GHz at 1555 nm, and a length of highly nonlinear photonic crystal fiber with low and flat dispersion. Stable picosecond soliton pulse trains with twofold to sevenfold enhancement in the repetition rate, relative to the FSR of the SFBG, have been achieved. The passive mode-locking mechanism that is at play in this laser relies on a dissipative four-wave mixing process and switching of repetition rate is realized simply by adjustment of the intracavity polarization controllers.

  14. Mode-locked Er:Yb-doped double-clad fiber laser with 75-nm tuning range.

    PubMed

    Meng, Yichang; Salhi, Mohamed; Niang, Alioune; Guesmi, Khmaies; Semaan, Georges; Sanchez, Francois

    2015-04-01

    We demonstrate a widely tunable Er:Yb-doped double-clad multiple-soliton fiber laser based on nonlinear polarization rotation (NPR). Based on both an artificial birefringent filtering effect of the cavity and population inversion related gain variation, the central wavelength can be continuously tuned over 75 nm range (1545-1620 nm). Wavelength tunability is achieved by controlling both the linear loss of the cavity and the polarization controllers (PCs). This is the widest tunable range yet reported in tunable passively mode-locked erbium-doped fiber lasers.

  15. Measurements of the Complex Permittivity of Liquid Helium-4 in the Millimeter Wave Range by a Whispering Gallery Mode Resonator

    NASA Astrophysics Data System (ADS)

    Smorodin, A. V.; Rybalko, A. S.; Konstantinov, D.

    2017-02-01

    We report an experimental study of the electrical properties of liquid helium-4 in the temperature range 1.2-3 K. The experiment is carried out in the millimeter wave range using a whispering gallery mode dielectric resonator, and the complex permittivity of liquid helium is extracted from the data using the resonant perturbation method. The results for the temperature dependence of the dielectric constant are consistent with the previous studies. In addition, we find strong enhancement of the loss tangent around the superfluid transition temperature.

  16. Population Structure, Diversity and Reproductive Mode of the Grape Phylloxera (Daktulosphaira vitifoliae) across Its Native Range

    PubMed Central

    Walker, M. Andrew

    2017-01-01

    Grape Phylloxera, Daktulosphaira vitifoliae, is a gall-forming insect that feeds on the leaves and roots of many Vitis species. The roots of the cultivated V. vinifera cultivars and hybrids are highly susceptible to grape phylloxera feeding damage. The native range of this insect covers most of North America, and it is particularly abundant in the eastern and central United States. Phylloxera was introduced from North America to almost all grape-growing regions across five of the temperate zone continents. It devastated vineyards in each of these regions causing large-scale disruptions to grape growers, wine makers and national economies. In order to understand the population diversity of grape phylloxera in its native range, more than 500 samples from 19 States and 34 samples from the introduced range (northern California, Europe and South America) were genotyped with 32 simple sequence repeat markers. STRUCTURE, a model based clustering method identified five populations within these samples. The five populations were confirmed by a neighbor-joining tree and principal coordinate analysis (PCoA). These populations were distinguished by their Vitis species hosts and their geographic locations. Samples collected from California, Europe and South America traced back to phylloxera sampled in the northeastern United States on V. riparia, with some influence from phylloxera collected along the Atlantic Coast and Central Plains on V. vulpina. Reproductive statistics conclusively confirmed that sexual reproduction is common in the native range and is combined with cyclical parthenogenesis. Native grape phylloxera populations were identified to be under Hardy-Weinberg equilibrium. The identification of admixed samples between many of these populations indicates that shared environments facilitate sexual reproduction between different host associated populations to create new genotypes of phylloxera. This study also found that assortative mating might occur across the

  17. The effects of oblique incidences on the XB mode conversion in the electron cyclotron range of frequency

    NASA Astrophysics Data System (ADS)

    Jia, Guozhang; Gao, Zhe

    2017-02-01

    The linear conversion from a fast extraordinary mode to a Bernstein mode (XB) in the electron cyclotron range of frequency is revisited numerically by using a simplified kinetic model. The corresponding wave equations are solved as a standard two-point boundary value problem, where the self-consistent boundary conditions are applied and the scattering coefficients are calculated accordingly. The numerical calculation of the XB conversion efficiency is compared with the analytical formula for the normal incidence (along the direction perpendicular to the equilibrium magnetic field and parallel to the density gradient), where a reasonable agreement is found. The effects of incident angles represented by refractive indexes on the conversion efficiency are analyzed. It is shown that as the incident angle deviates from the normal incidence, the efficiency of XB conversion decreases significantly. The results also indicate that the power loss in the XB process can be ascribed to the reflected fast extraordinary mode and the reflected-converted ordinary mode. The symmetry of the conversion efficiency about the incident angle is discussed, and the rigid restriction on the scale length of the density variation for effective XB conversions can be possibly alleviated through altering the injection direction in realistic experiments.

  18. Effects of Environmental Variability on Long-Range Underwater Sound Propagation: Mode Processing of LOAPEX

    DTIC Science & Technology

    2011-05-01

    existing theory to the environments with strong range dependence. In addition, a study of oceanic acoustic response to acidification has been made...implementation. The second paper is a study of ambient noise level change in the ocean due to acidification . Also two papers devoted to the modal analysis...addition, a study of oceanic acoustic response to acidification has been made. Two papers have been published during this study. The first paper focuses

  19. The Coupled-Mode Method for Transmission Loss Calculation in a Range- Dependent Oceanic Environment

    DTIC Science & Technology

    1989-02-27

    theory, with eigenray calculations to estimate the coupling coefficients, to simplify the solution to the propagation in a range-dependent...Then Equation (18) becomes V2p + k2p - V2U (24) which, in an unbounded medium, has a general homogeneous solution consisting of an outgoing and an...transform back using Equation (39) to obtain (r,z). The solution of this inhomogeneous equation can be written as the sum of the homogeneous solution and

  20. Optically stabilized Erbium fiber frequency comb with hybrid mode-locking and a broad tunable range of repetition rate.

    PubMed

    Yang, Honglei; Wu, Xuejian; Zhang, Hongyuan; Zhao, Shijie; Yang, Lijun; Wei, Haoyun; Li, Yan

    2016-12-01

    We present an optically stabilized Erbium fiber frequency comb with a broad repetition rate tuning range based on a hybrid mode-locked oscillator. We lock two comb modes to narrow-linewidth reference lasers in turn to investigate the best performance of control loops. The control bandwidth of fast and slow piezoelectric transducers reaches 70 kHz, while that of pump current modulation with phase-lead compensation is extended to 32 kHz, exceeding laser intrinsic response. Eventually, simultaneous lock of both loops is realized to totally phase-stabilize the comb, which will facilitate precision dual-comb spectroscopy, laser ranging, and timing distribution. In addition, a 1.8-MHz span of the repetition rate is achieved by an automatic optical delay line that is helpful in manufacturing a secondary comb with a similar repetition rate. The oscillator is housed in a homemade temperature-controlled box with an accuracy of ±0.02  K, which not only keeps high signal-to-noise ratio of the beat notes with reference lasers, but also guarantees self-starting at the same mode-locking every time.

  1. Analyses of kinetic glass transition in short-range attractive colloids based on time-convolutionless mode-coupling theory

    NASA Astrophysics Data System (ADS)

    Narumi, Takayuki; Tokuyama, Michio

    2017-03-01

    For short-range attractive colloids, the phase diagram of the kinetic glass transition is studied by time-convolutionless mode-coupling theory (TMCT). Using numerical calculations, TMCT is shown to recover all the remarkable features predicted by the mode-coupling theory for attractive colloids: the glass-liquid-glass reentrant, the glass-glass transition, and the higher-order singularities. It is also demonstrated through the comparisons with the results of molecular dynamics for the binary attractive colloids that TMCT improves the critical values of the volume fraction. In addition, a schematic model of three control parameters is investigated analytically. It is thus confirmed that TMCT can describe the glass-glass transition and higher-order singularities even in such a schematic model.

  2. Active accumulation of very diluted biomolecules by nano-dispensing for easy detection below the femtomolar range

    NASA Astrophysics Data System (ADS)

    Grilli, S.; Miccio, L.; Gennari, O.; Coppola, S.; Vespini, V.; Battista, L.; Orlando, P.; Ferraro, P.

    2014-11-01

    Highly sensitive detection of biomolecules is of paramount interest in many fields including biomedicine, safety and eco-pollution. Conventional analyses use well-established techniques with detection limits ~1 pM. Here we propose a pyro-concentrator able to accumulate biomolecules directly onto a conventional binding surface. The operation principle is relatively simple but very effective. Tiny droplets are drawn pyro-electro-dynamically and released onto a specific site, thus increasing the sensitivity. The reliability of the technique is demonstrated in case of labelled oligonucleotides diluted serially. The results show the possibility to detect very diluted oligonucleotides, down to a few hundreds of attomoles. Excellent results are shown also in case of a sample of clinical interest, the gliadin, where a 60-fold improved detection limit is reached, compared with standard ELISA. This method could open the way to a mass-based technology for sensing molecules at very low concentrations, in environmental as well as in diagnostics applications.

  3. Fine-tuning of whispering gallery modes in on-chip silica microdisk resonators within a full spectral range

    NASA Astrophysics Data System (ADS)

    Henze, Rico; Pyrlik, Christoph; Thies, Andreas; Ward, Jonathan M.; Wicht, Andreas; Benson, Oliver

    2013-01-01

    We investigate an efficient method for fine-tuning whispering gallery mode resonances in disk-type silica microresonators to reach an arbitrary frequency within the free spectral range of the system. This method is based on a post-production hydrofluoric acid etching process to precisely resize the radius of such microresonators. We show the effectiveness of this approach by tuning their resonance frequency within 10 GHz of specific hydrogen cyanide reference lines (P16, P18). This technique allows for simple and exact matching of narrow-linewidth lasers or spectroscopic lines with the high-Q resonances of on-chip silica microresonators.

  4. Dominant modes of variation in the annual progression of snow accumulation and melt in the Sierra Nevada

    NASA Astrophysics Data System (ADS)

    Montoya, E.; Meiring, W.; Dozier, J.

    2014-12-01

    Snow in the Sierra Nevada is an important source of water for California. Due to advances in technology, the environmental sciences are more commonly taking measurements from continuous processes, and sample measurements of snow water equivalent (SWE) from snow pillows are one such example. Snow pillows provide daily samples from the continuous SWE yearly profile if SWE measurements are viewed as a continuous function of time. We examine the dominant modes of variation in the timing of snowpack events using functional principal component analysis. Additionally, we examine the associations between the dominant modes of variation with large-scale climate indices and spatial location.

  5. Wide range local resistance imaging on fragile materials by conducting probe atomic force microscopy in intermittent contact mode

    NASA Astrophysics Data System (ADS)

    Vecchiola, Aymeric; Chrétien, Pascal; Delprat, Sophie; Bouzehouane, Karim; Schneegans, Olivier; Seneor, Pierre; Mattana, Richard; Tatay, Sergio; Geffroy, Bernard; Bonnassieux, Yvan; Mencaraglia, Denis; Houzé, Frédéric

    2016-06-01

    An imaging technique associating a slowly intermittent contact mode of atomic force microscopy (AFM) with a home-made multi-purpose resistance sensing device is presented. It aims at extending the widespread resistance measurements classically operated in contact mode AFM to broaden their application fields to soft materials (molecular electronics, biology) and fragile or weakly anchored nano-objects, for which nanoscale electrical characterization is highly demanded and often proves to be a challenging task in contact mode. Compared with the state of the art concerning less aggressive solutions for AFM electrical imaging, our technique brings a significantly wider range of resistance measurement (over 10 decades) without any manual switching, which is a major advantage for the characterization of materials with large on-sample resistance variations. After describing the basics of the set-up, we report on preliminary investigations focused on academic samples of self-assembled monolayers with various thicknesses as a demonstrator of the imaging capabilities of our instrument, from qualitative and semi-quantitative viewpoints. Then two application examples are presented, regarding an organic photovoltaic thin film and an array of individual vertical carbon nanotubes. Both attest the relevance of the technique for the control and optimization of technological processes.

  6. Long-range transported atmospheric pollutants in snowpacks accumulated at different altitudes in the Tatra Mountains (Slovakia).

    PubMed

    Arellano, Lourdes; Fernández, Pilar; Tatosova, Jolana; Stuchlik, Evzen; Grimalt, Joan O

    2011-11-01

    Persistent organic pollutants (POPs), including polychlorobiphenyls (PCB), endosulfans, hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), polybromodiphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs), were analyzed in snowpack samples collected along an altitudinal gradient (1683-2634 meters above sea level) in the High Tatra Mountains (Slovakia). All analyzed compounds were found at all altitudes, pointing to their global distribution. The presence of PBDEs, particularly BDE 209, in the snowpack samples is especially relevant, as it reflects the air transport capacity of this low volatile, very hydrophobic pollutant to remote mountain regions. The most abundant compounds at all altitudes were PAHs, with mean values ranging from 90 to 300 ngL(-1), 1 order of magnitude higher than concentrations of other compounds. PCBs (sum of PCB 28, 52, 101, 118, 153, 138, and 180) and BDE 209 were the dominant organohalogen pollutants, with concentrations from 550 to 1600 pg L(-1) and from 670 to 2000 pgL(-1), respectively. Low brominated PBDEs, endosulfans, HCHs and HCB were consistently found in all samples at lower concentrations. The concentrations of these compounds correlated positively with altitude (i.e., negatively with temperature), which is consistent with cold-trapping effects. The regression coefficients were positive and statistically significant (p < 0.05) for all compounds except BDE 209, endosulfan sulfate, HCB and α-HCH. Contrariwise, the concentrations of BDE 209 and endosulfan sulfate exhibited a statistically significant positive correlation with total particle amount, which agrees with long-range atmospheric transport associated to aerosols according to the physical-chemical properties of these compounds. Snow specific surface area, which determines the maximum amount of each organic compound that can be sorbed by snow, proved utile for describing the distribution of the more volatile compounds, namely α-HCB and HCB, in the snowpack.

  7. Wide wavelength range tunable one-dimensional silicon nitride nano-grating guided mode resonance filter based on azimuthal rotation

    NASA Astrophysics Data System (ADS)

    Yukino, Ryoji; Sahoo, Pankaj K.; Sharma, Jaiyam; Takamura, Tsukasa; Joseph, Joby; Sandhu, Adarsh

    2017-01-01

    We describe wavelength tuning in a one dimensional (1D) silicon nitride nano-grating guided mode resonance (GMR) structure under conical mounting configuration of the device. When the GMR structure is rotated about the axis perpendicular to the surface of the device (azimuthal rotation) for light incident at oblique angles, the conditions for resonance are different than for conventional GMR structures under classical mounting. These resonance conditions enable tuning of the GMR peak position over a wide range of wavelengths. We experimental demonstrate tuning over a range of 375 nm between 500 nm˜875 nm. We present a theoretical model to explain the resonance conditions observed in our experiments and predict the peak positions with show excellent agreement with experiments. Our method for tuning wavelengths is simpler and more efficient than conventional procedures that employ variations in the design parameters of structures or conical mounting of two-dimensional (2D) GMR structures and enables a single 1D GMR device to function as a high efficiency wavelength filter over a wide range of wavelengths. We expect tunable filters based on this technique to be applicable in a wide range of fields including astronomy and biomedical imaging.

  8. Potential lipid accumulation and growth characteristic of the green alga Chlorella with combination cultivation mode of nitrogen (N) and phosphorus (P).

    PubMed

    Li, Yuqin; Han, Fangxin; Xu, Hua; Mu, Jinxiu; Chen, Di; Feng, Bo; Zeng, Hongyan

    2014-12-01

    This study aimed to evaluate the potential lipid accumulation of an oleaginous Chlorella protothecoides by combination cultivation mode of nitrogen (N) and phosphorus (P). Under co-deficiency of N and P, the largest lipid content (55.8%) was accomplished in C. protothecoides, which was higher than either sole P-deficiency (32.77%) or N-deficiency (52.5%), or co-repletion of N and P (control) (22.17%). However, the highest lipid productivity (224.14mg/L/day) with combination mode of N-deficiency and P-repletion represented 1.19-3.70-fold more than that of control, P-deficiency/limitation, and co-deficiency of N and P, respectively. This indicating N-deficiency plus P-repletion was a promising lipid trigger to motivate lipid accumulation in C. protothecoides cells. Further, difference gel electrophoresis (DIGE)-based proteomics was employed to reveal the molecular pathways associated with lipid biosynthesis. These results provide the foundation to develop engineering strategies targeting lipid productivity for industrial production of microalgae-based biodiesel.

  9. Using the accumulation of CBD-extractable iron and clay content to estimate soil age on stable surfaces and nearby slopes, Front Range, Colorado

    NASA Astrophysics Data System (ADS)

    Dethier, David P.; Birkeland, Peter W.; McCarthy, James A.

    2012-11-01

    In many transport-limited environments, morphology, pedogenic iron and clay content provide a basis for estimating the exposure age of soils and associated landforms. We measured citrate-buffered dithionite (CBD)-extractable Fe (Fed) and clay concentration in fresh rock, saprolite, morainal and colluvial materials, and soil horizons from stable surfaces and hillslopes in the Colorado Front Range. Fresh igneous and high-grade metamorphic rocks contain < 1% Fed and 1 to 5% clay. As bedrock and surficial deposits age, Fed and clay accumulate from weathering and dustfall. Late Holocene regolith at warm, dry sites contains small amounts of Fed and clay, but relatively moist soils developed on early Holocene cirque deposits contain as much as 1.5% Fed and 8% clay. Concentrations and total profile accumulation of Fed and clay increase with age in soils developed on stable surfaces of glacial deposits as old as ~ 130 kyr. On stable sites, Fed and clay accumulation from weathering and dust is ~ 0.02 g cm- 2 kyr- 1 and ~ 0.2 g cm- 2 kyr- 1, respectively. We used the Fed and clay inventory in soil profiles at dated, stable Front Range surfaces to calculate accumulation functions, which allowed us to estimate soil age at hillslope sites. Heterogeneous parent material, particularly on hillslopes, and climate-related effects add to variability in measured relations. Mobile regolith in Gordon Gulch, one of the Boulder Creek Critical Zone Observatory (CZO) catchments, yields profile ages from about 0.5 to 5 × 104 yr, comparable to values measured using other techniques. Calculated profile ages are older on a north- vs. south-facing slope and increase from the drainage divide to the footslope. Ages calculated for stabilized colluvium and well-developed buried profiles at nearby hillslope sites (Lefthand, Ward and Rollinsville) suggest that these soils have stabilized over periods > 105 yr. In the absence of radiometric ages, the accumulation of Fed and clay in soils on stable

  10. A reconfigurable multi-mode multi-band transmitter with integrated frequency synthesizer for short-range wireless communication

    NASA Astrophysics Data System (ADS)

    Nan, Qi; Fan, Chen; Lingwei, Zhang; Xiaoman, Wang; Baoyong, Chi

    2013-09-01

    A reconfigurable multi-mode direct-conversion transmitter (TX) with integrated frequency synthesizer (FS) is presented. The TX as well as the FS is designed with a flexible architecture and frequency plan, which helps to support all the 433/868/915 MHz ISM band signals, with the reconfigurable bandwidth from 250 kHz to 2 MHz. In order to save power and chip area, only one 1.8 GHz VCO is adopted to cover the whole frequency range. All the operation modes can be regulated in real time by configuring the integrated register-bank through an SPI interface. Implemented in 180 nm CMOS, the FS achieves a frequency coverage of 320-460 MHz and 620-920 MHz. The lowest phase noise can be -107 dBc/Hz at a 100 kHz offset and -126 dBc/Hz at a 1 MHz offset. The transmitter features a + 10.2 dBm peak output power with a +9.5 dBm 1-dB-compression point and 250 kHz/500 kHz/1 MHz/2 MHz reconfigurable signal bandwidth.

  11. Lower hybrid current drive and ion cyclotron range of frequencies heating experiments in H-mode plasmas in Experimental Advanced Superconducting Tokomak

    SciTech Connect

    Zhang, X. J.; Wan, B. N. Zhao, Y. P.; Ding, B. J.; Xu, G. S.; Gong, X. Z.; Li, J. G.; Lin, Y.; Wukitch, S.; Taylor, G.; Noterdaeme, J. M.; Braun, F.; Magne, R.; Litaudon, X.; Kumazawa, R.; Kasahara, H.

    2014-06-15

    An ion cyclotron range of frequencies (ICRF) system with power up to 6.0 MW and a lower hybrid current drive (LHCD) system up to 4 MW have been applied for heating and current drive experiments in Experimental Advanced Superconducting Tokomak (EAST). Significant progress has been made with ICRF heating and LHCD for realizing the H-mode plasma operation in EAST. During 2010 and 2012 experimental campaigns, ICRF heating experiments were carried out at the fixed frequency of 27MHz, achieving effective ions and electrons heating with the H minority heating (H-MH) mode. The H-MH mode produced good plasma performance, and realized H-mode using ICRF power alone in 2012. In 2010, H-modes were generated and sustained by LHCD alone, where lithium coating and gas puffing near the mouth of the LH launcher were applied to improve the LHCD power coupling and penetration into the core plasmas of H-modes. In 2012, the combination of LHCD and ICRH power extended the H-mode duration up to over 30 s. H-modes with various types of edge localized modes (ELMs) have been achieved with H{sub IPB98}(y, 2) ranging from 0.7 to over unity. A brief overview of LHCD and ICRF Heating experiment and their application in achieving H-mode operation during these two campaigns will be presented.

  12. Evaluation of GAFCHROMIC EBT2 dosimetry for the low dose range using a flat-bed scanner with the reflection mode.

    PubMed

    Gotanda, Tatsuhiro; Katsuda, Toshizo; Akagawa, Takuya; Gotanda, Rumi; Tabuchi, Akihiko; Yamamoto, Kenyu; Kuwano, Tadao; Yatake, Hidetoshi; Yabunaka, Koichi; Takeda, Yoshihiro

    2013-03-01

    Recently developed radiochromic films can easily be used to measure absorbed doses because they do not need development processing and indicate a density change that depends on the absorbed dose. However, in GAFCHROMIC EBT2 dosimetry (GAF-EBT2) as a radiochromic film, the precision of the measurement was compromised, because of non-uniformity problems caused by image acquisition using a flat-bed scanner with a transmission mode. The purpose of this study was to improve the precision of the measurement using a flat-bed scanner with a reflection mode at the low absorbed dose dynamic range of GAF-EBT2. The calibration curves of the absorbed dose versus the film density for GAF-EBT2 were provided. X-rays were exposed in the range between ~0 and 120 mGy in increments of about 12 mGy. The results of the method using a flat-bed scanner with the transmission mode were compared with those of the method using the same scanner with the reflection mode. The results should that the determination coefficients (r (2) ) for the straight-line approximation of the calibration curve using the reflection mode were higher than 0.99, and the gradient using the reflection mode was about twice that of the one using the transmission mode. The non-uniformity error that is produced by a flat-bed scanner with the transmission mode setting could be almost eliminated by converting from the transmission mode to the reflection mode. In light of these findings, the method using a flat-bed scanner with the reflection mode (only using uniform white paper) improved the precision of the measurement for the low absorbed dose range.

  13. Effects of particle shape, hematite content and semi-external mixing with carbonaceous components on the optical properties of accumulation mode mineral dust

    NASA Astrophysics Data System (ADS)

    Mishra, S. K.; Tripathi, S. N.; Aggarwal, S. G.; Arola, A.

    2010-12-01

    The radiative forcing estimation of the polluted mineral dust is limited due to lack of morphological analysis, mixing state with the carbonaceous components and the hematite content in the pure dust. The accumulation mode mineral dust has been found to mix with anthropogenically produced black carbon, organic carbon and brown carbon during long range transport. The above features of the polluted dust are not well accounted in the optical models and lead the uncertainty in the numerical estimation of their radiative impact. The Semi-external mixing being a prominent mixing of dust and carbonaceous components has not been studied in details so for compared to core-shell, internal and external mixing studies. In present study, we consider the pure mineral dust composed of non-metallic components (such as Quartz, Feldspar, Mica and Calcite) and metalic component like hematite (Fe2O3). The hematite percentage in the pure mineral dust governs its absorbance. Based on this hematite variation, the hematite fraction in pure mineral dust has been constrained between 0-8%. The morphological and mineralogical characterization of the polluted dust led to consider the three sphere, two sphere and two spheroid model shapes for polluted dust particle system. The pollution gives rise to various light absorbing aerosol components like black carbon, brown carbon and organic carbon (comprising of HUmic-Like Substances, HULIS) in the atmosphere. The entire above discussed model shapes have been considered for the mineral dust getting polluted with (1) organic carbon (especially HULIS component) (2) Brown carbon and (3) black carbon by making a semi-external mixture with pure mineral dust. The optical properties (like Single Scattering Albedo, SSA; Asymmetry parameter, g and Extinction efficiency, Qext) of above model shapes for the polluted dust have been computed using Discrete Dipole Approximation, DDA code. For above model shapes, the SSA was found to vary depending on hematite

  14. From fine-scale foraging to home ranges: a semivariance approach to identifying movement modes across spatiotemporal scales.

    PubMed

    Fleming, Chris H; Calabrese, Justin M; Mueller, Thomas; Olson, Kirk A; Leimgruber, Peter; Fagan, William F

    2014-05-01

    Understanding animal movement is a key challenge in ecology and conservation biology. Relocation data often represent a complex mixture of different movement behaviors, and reliably decomposing this mix into its component parts is an unresolved problem in movement ecology. Traditional approaches, such as composite random walk models, require that the timescales characterizing the movement are all similar to the usually arbitrary data-sampling rate. Movement behaviors such as long-distance searching and fine-scale foraging, however, are often intermixed but operate on vastly different spatial and temporal scales. An approach that integrates the full sweep of movement behaviors across scales is currently lacking. Here we show how the semivariance function (SVF) of a stochastic movement process can both identify multiple movement modes and solve the sampling rate problem. We express a broad range of continuous-space, continuous-time stochastic movement models in terms of their SVFs, connect them to relocation data via variogram regression, and compare them using standard model selection techniques. We illustrate our approach using Mongolian gazelle relocation data and show that gazelle movement is characterized by ballistic foraging movements on a 6-h timescale, fast diffusive searching with a 10-week timescale, and asymptotic diffusion over longer timescales.

  15. Single mode operation with mid-IR hollow fibers in the range 5.1-10.5 µm.

    PubMed

    Sampaolo, Angelo; Patimisco, Pietro; Kriesel, Jason M; Tittel, Frank K; Scamarcio, Gaetano; Spagnolo, Vincenzo

    2015-01-12

    Single mode beam delivery in the mid-infrared spectral range 5.1-10.5 μm employing flexible hollow glass waveguides of 15 cm and 50 cm lengths, with metallic/dielectric internal layers and a bore diameter of 200 μm were demonstrated. Three quantum cascade lasers were coupled with the hollow core fibers. For a fiber length of 15 cm, we measured losses down to 1.55 dB at 5.4 μm and 0.9 dB at 10.5 μm. The influence of the launch conditions in the fiber on the propagation losses and on the beam profile at the waveguide exit was analyzed. At 10.5 µm laser wavelength we found near perfect agreement between measured and theoretical losses, while at ~5 µm and ~6 µm wavelengths the losses were higher than expected. This discrepancy can be explained considering an additional scattering loss effect, which scales as 1/λ(2) and is due to surface roughness of the metallic layer used to form the high-reflective internal layer structure of the hollow core waveguide.

  16. BRIEF COMMUNICATIONS: Single-mode laser amplifier operating in the 1.3 μm range and using a buried stripe heterostructure

    NASA Astrophysics Data System (ADS)

    Huy, Bui; Luc, Vu V.; Duraev, V. P.; Eliseev, P. G.; Man'ko, Margarita A.; Nedelin, E. T.; Thi Thanh Truong, Nguyên; Chyong Thong Nhat, Nguyên

    1989-08-01

    Single-mode laser amplifiers were developed for the 1.3 μm range. The radiation was coupled in and out of these amplifiers by single-mode fiber waveguides. Statistical characteristics of the amplification and the optoelectronic signal were investigated. An unsaturated gain of 10 dB was obtained for a small signal in a traveling-wave amplifier. The saturation power of the input signal was 16 μW.

  17. Tungsten divertor sourcing in DIII-D H-mode discharges and its impact on core impurity accumulation in different ELM regimes

    NASA Astrophysics Data System (ADS)

    Abrams, T.; Ding, R.; Guterl, J.; Briesemeister, A.; Unterberg, E. A.; Guo, H. Y.; Leonard, A. W.; Thomas, D. M.; McLean, A. G.; Victor, B.; Rudakov, D.; Grierson, B.; Watkins, J. G.; Elder, J. D.; Stangeby, P. C.

    2016-10-01

    Significant progress has been made understanding W sourcing during Type I ELMy H-mode on DIII-D using fast high-resolution measurements of W sourcing coupled with OEDGE/ERO and TRIM.SP modeling. ERO modeling of the inter-ELM phase, using a new OEDGE capability for charge state-resolved carbon ion fluxes and a material mixing model, shows measured W erosion is well explained by C- >W sputtering. Ion impact energies in the DIII-D divertor during ELMs, inferred from ratios of heat flux to ion flux, are 200-500 eV. Comparisons with TRIM.SP indicate C- >W sputtering dominates W sourcing during ELMs. This is in contrast to JET where ion impact energies are 3-5 keV during ELMs, predicted by the ``free streaming model,'' and D- >W sputtering strongly contributes to W sourcing. Fast measurements of W erosion dynamics during ELMs agree well with TRIM.SP-based sputtering models assuming C/W surface concentrations of 0.5-0.8 and a 2% C2+ ion flux fraction. Core W accumulation and SOL W density measurements made during the DIII-D high-Z tile array mini-campaign correlate with ELM frequency and W source rate. Supported by US DOE under DE-FC02-04ER54698.

  18. Modulation of TE propagation modes in rectangular metal waveguide with integrated graphene structure in the sub-terahertz frequency range

    NASA Astrophysics Data System (ADS)

    Shkerdin, Gennady; Guo-Qiang, HE; Alkorre, Hameda I.; Stiens, Johan H.

    2017-01-01

    The propagation of TE modes in a rectangular metal waveguide with an integrated structure of finite length containing a graphene monolayer was studied by a modal decomposition method. The modal decomposition method generates a number of linear algebraic equations related to waveguide modes taken into account. The system of linear algebraic equations for the amplitudes of all modes was derived taking into account the propagation as well as a number of local evanescent modes. Truncation errors in the function of the number of modes taken were quantified by using the discontinuities of the boundary conditions for the transverse electric and magnetic field components at the interface of the discontinuities of the structure. The transmitted and reflected TE01 mode amplitudes were calculated versus the graphene layer length, its position inside the waveguide cavity and the graphene electrons chemical potential. It was shown that the symmetrical positioning of the graphene layer inside the waveguide cavity is the most suitable to achieve the largest amplitude modulation, whereas an asymmetrical positioning is suitable to achieve a large phase modulation of the transmitted mode. It was shown that the phase modulation increases with a transmission coefficient modulation increase and decreases with a transmission coefficient increase. It was found that the phase modulation firstly increases almost proportionally with the graphene layer length for relatively short structures; however, after passing through a maximum, the phase modulation becomes almost constant and hence only weakly dependent on the graphene layer length. Typical phase modulation values turn out to be about 15-20 degrees for minimal transmission coefficients of about 0.6-0.4 however, the phase modulation reaches a value of about 45 degrees if the transmission coefficient modulation equals 50%.

  19. New Method to Study the Vibrational Modes of Biomolecules in the Terahertz Range Based on a Single-Stage Raman Spectrometer

    PubMed Central

    2017-01-01

    The low-frequency vibrational (LFV) modes of biomolecules reflect specific intramolecular and intermolecular thermally induced fluctuations that are driven by external perturbations, such as ligand binding, protein interaction, electron transfer, and enzymatic activity. Large efforts have been invested over the years to develop methods to access the LFV modes due to their importance in the studies of the mechanisms and biological functions of biomolecules. Here, we present a method to measure the LFV modes of biomolecules based on Raman spectroscopy that combines volume holographic filters with a single-stage spectrometer, to obtain high signal-to-noise-ratio spectra in short acquisition times. We show that this method enables LFV mode characterization of biomolecules even in a hydrated environment. The measured spectra exhibit distinct features originating from intra- and/or intermolecular collective motion and lattice modes. The observed modes are highly sensitive to the overall structure, size, long-range order, and configuration of the molecules, as well as to their environment. Thus, the LFV Raman spectrum acts as a fingerprint of the molecular structure and conformational state of a biomolecule. The comprehensive method we present here is widely applicable, thus enabling high-throughput study of LFV modes of biomolecules. PMID:28393138

  20. On the dispersion management of fluorite whispering-gallery mode resonators for Kerr optical frequency comb generation in the telecom and mid-infrared range.

    PubMed

    Lin, Guoping; Chembo, Yanne K

    2015-01-26

    Optical whispering gallery mode (WGM) resonators have been very attracting platforms for versatile Kerr frequency comb generations. We report a systematic study on the material dispersion of various optical materials that are capable of supporting quality factors above 109. Using an analytical approximation of WGM resonant frequencies in disk resonators, we investigate the effect of the geometry and transverse mode order on the total group-velocity dispersion (GVD). We demonstrate that the major radii and the radial mode indices play an important role in tailoring the GVD of WGM resonators. In particular, our study shows that in WGM disk-resonators, the polar families of modes have very similar GVD, while the radial families of modes feature dispersion values that can differ by up to several orders of magnitude. The effect of these giant dispersion shifts are experimentally evidenced in Kerr comb generation with magnesium fluoride. From a more general perspective, this critical feature enables to push the zero-dispersion wavelength of fluorite crystals towards the mid-infrared (mid-IR) range, thereby allowing for efficient Kerr comb generation in that spectral range. We show that barium fluoride is the most interesting crystal in this regard, due to its zero dispersion wavelength (ZDW) at 1.93 μm and an optimal dispersion profile in the mid-IR regime. We expect our results to facilitate the design of different platforms for Kerr frequency comb generations in both telecommunication and mid-IR spectral ranges.

  1. Accumulate repeat accumulate codes

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    In this paper we propose an innovative channel coding scheme called 'Accumulate Repeat Accumulate codes' (ARA). This class of codes can be viewed as serial turbo-like codes, or as a subclass of Low Density Parity Check (LDPC) codes, thus belief propagation can be used for iterative decoding of ARA codes on a graph. The structure of encoder for this class can be viewed as precoded Repeat Accumulate (RA) code or as precoded Irregular Repeat Accumulate (IRA) code, where simply an accumulator is chosen as a precoder. Thus ARA codes have simple, and very fast encoder structure when they representing LDPC codes. Based on density evolution for LDPC codes through some examples for ARA codes, we show that for maximum variable node degree 5 a minimum bit SNR as low as 0.08 dB from channel capacity for rate 1/2 can be achieved as the block size goes to infinity. Thus based on fixed low maximum variable node degree, its threshold outperforms not only the RA and IRA codes but also the best known LDPC codes with the dame maximum node degree. Furthermore by puncturing the accumulators any desired high rate codes close to code rate 1 can be obtained with thresholds that stay close to the channel capacity thresholds uniformly. Iterative decoding simulation results are provided. The ARA codes also have projected graph or protograph representation that allows for high speed decoder implementation.

  2. Theory of plasmonic femtosecond pulse generation by mode-locking of long-range surface plasmon polariton lasers.

    PubMed

    Kim, Kwang-Hyon; Husakou, Anton; Herrmann, Joachim

    2012-01-02

    We develop a semiclassical theory of passively mode-locked surface plasmon polariton (SPP) lasers based on a SPP Bragg resonator with a metal film deposited on a polymer host and adjacent layers of a slow saturable absorber and a slow saturable gain medium. The mode-locked laser dynamics is studied for the case that both the gain medium and the saturable absorber are solid-state dyes. The SPP laser pulse parameters are calculated in dependence on layer thicknesses of the metal film and pump parameters. We predict the possibility of SPP pulse generation with ∼ 100 fs pulse duration.

  3. Variation in sulfur and selenium accumulation is controlled by naturally occurring isoforms of the key sulfur assimilation enzyme ADENOSINE 5'-PHOSPHOSULFATE REDUCTASE2 across the Arabidopsis species range.

    PubMed

    Chao, Dai-Yin; Baraniecka, Patrycja; Danku, John; Koprivova, Anna; Lahner, Brett; Luo, Hongbing; Yakubova, Elena; Dilkes, Brian; Kopriva, Stanislav; Salt, David E

    2014-11-01

    Natural variation allows the investigation of both the fundamental functions of genes and their role in local adaptation. As one of the essential macronutrients, sulfur is vital for plant growth and development and also for crop yield and quality. Selenium and sulfur are assimilated by the same process, and although plants do not require selenium, plant-based selenium is an important source of this essential element for animals. Here, we report the use of linkage mapping in synthetic F2 populations and complementation to investigate the genetic architecture of variation in total leaf sulfur and selenium concentrations in a diverse set of Arabidopsis (Arabidopsis thaliana) accessions. We identify in accessions collected from Sweden and the Czech Republic two variants of the enzyme ADENOSINE 5'-PHOSPHOSULFATE REDUCTASE2 (APR2) with strongly diminished catalytic capacity. APR2 is a key enzyme in both sulfate and selenate reduction, and its reduced activity in the loss-of-function allele apr2-1 and the two Arabidopsis accessions Hodonín and Shahdara leads to a lowering of sulfur flux from sulfate into the reduced sulfur compounds, cysteine and glutathione, and into proteins, concomitant with an increase in the accumulation of sulfate in leaves. We conclude from our observation, and the previously identified weak allele of APR2 from the Shahdara accession collected in Tadjikistan, that the catalytic capacity of APR2 varies by 4 orders of magnitude across the Arabidopsis species range, driving significant differences in sulfur and selenium metabolism. The selective benefit, if any, of this large variation remains to be explored.

  4. Geomagnetic Investigation of Sandstone Dikes of the Colorado Front Range, for Determination of Age and Mode of Emplacement

    NASA Astrophysics Data System (ADS)

    Freedman, D.; Petronis, M. S.; Siddoway, C. S.

    2012-12-01

    In the Colorado Front Range, an array of sandstone dikes has intrigued geologists for over a century (Cross 1894,GSAB, 5, 525). Within their crystalline host, the dikes reach widths >7m and have a lateral extent of 70km along the Ute Pass Fault (UPF). The essential questions of sediment source, emplacement mode, and age of the dikes are unanswered. We present new paleomagnetic, rock magnetic, and anisotropy of magnetic susceptibility (AMS) results used to determine the age and emplacement behavior of the dikes. The eleven dikes selected for magnetic studies have sharp, planar margins, and share the systematic geometry of the NW striking subvertical dike array. They exhibit little or no overprint by brittle fracturing/shear associated with the UPF. Our approach involved the use of paleomagnetic techniques to isolate the characteristic remanent magnetization (ChRM), which we used to limit the age of the dikes' magnetization. Anisotropy of magnetic susceptibility (AMS),arising from alignment of detrital magnetite, serves as a proxy for the orientation of flow during dike emplacement. U-Pb detrital zircon ages, obtained previously, did not provide a useful constraint on emplacement age because the dominant age matches that of the prevalent host,1.03Ga Pikes Peak Granite. IRM acquisition experiments were performed to identify the principal magnetic phases as a mixture of Fe-Ti oxide phases, likely to be low-Ti magnetite and hematite. The sandstone consists of sub-rounded to rounded sand-sized quartz, angular feldspar (<5%), and detrital magnetite; selected samples have uniform grain size and uniform color arising from hematite cement. Although direct cover relationships are not preserved, a portion of the study sites are proximal to in situ near-horizontal sedimentary cover rocks that offer evidence against large tectonic rotation. Cores were collected using a gas-powered drill with a diamond bit and oriented using a sun compass. Where possible, cores were obtained on

  5. Indoor/outdoor relationships of quasi-ultrafine, accumulation and coarse mode particles in school environments in Barcelona: chemical composition and sources

    NASA Astrophysics Data System (ADS)

    Viana, M.; Rivas, I.; Querol, X.; Alastuey, A.; Sunyer, J.; Álvarez-Pedrerol, M.; Bouso, L.; Sioutas, C.

    2013-12-01

    The mass concentration, chemical composition and sources of quasi-ultrafine (quasi-UFP, PM0.25), accumulation (PM0.25-2.5) and coarse mode (PM2.5-10) particles were determined in indoor and outdoor air at 39 schools in Barcelona (Spain). Quasi-UFP mass concentrations measured (25.6 μg m-3 outdoors, 23.4 μg m-3 indoors) are significantly higher than those reported in other studies, and characterised by higher carbonaceous and mineral matter contents and a lower proportion of secondary inorganic ions. Results suggest that quasi-UFPs in Barcelona are affected by local sources in the schools, mainly human activity (e.g. organic material from textiles, etc.; contributing 23-46% to total quasi-UFP mass) and playgrounds (in the form of mineral matter, contributing about 9% to the quasi-UFP mass). The particle size distribution of toxicologically relevant metals and major aerosol components was characterised, displaying bimodal size distributions for most elements and components, and a unimodal distribution for inorganic salts (ammonium nitrate and sulphate) and elemental carbon (EC). Regarding metals, Ni and Cr were partitioned mainly in quasi-UFPs and could thus be of interest for epidemiological studies, given their high redox properties. Children exposure to quasi-UFP mass and chemical species was assessed by comparing the concentrations measured at urban background and traffic areas schools. Finally, three main indoor sources across all size fractions were identified by assessing indoor/outdoor ratios (I/O) of PM species used as their tracers: human activity (organic material), cleaning products, paints and plastics (Cl- source), and a metallic mixed source (comprising combinations of Cu, Zn, Co, Cd, Pb, As, V and Cr).

  6. Restraint of range walk error in a Geiger-mode avalanche photodiode lidar to acquire high-precision depth and intensity information.

    PubMed

    Xu, Lu; Zhang, Yu; Zhang, Yong; Yang, Chenghua; Yang, Xu; Zhao, Yuan

    2016-03-01

    There exists a range walk error in a Geiger-mode avalanche photodiode (Gm-APD) lidar because of the fluctuation in the number of signal photoelectrons. To restrain this range walk error, we propose a new returning-wave signal processing technique based on the Poisson probability response model and the Gaussian functions fitting method. High-precision depth and intensity information of the target at the distance of 5 m is obtained by a Gm-APD lidar using a 6 ns wide pulsed laser. The experiment results show that the range and intensity precisions are 1.2 cm and 0.015 photoelectrons, respectively.

  7. Differential responses to different light spectral ranges of violaxanthin de-epoxidation and accumulation of Cbr, an algal homologue of plant early light inducible proteins, in two strains of Dunaliella.

    PubMed

    Banet; Pick; Malkin; Zamir

    1999-11-01

    Unicellular green algae of the genus Dunaliella, similar to higher plants, respond to light stress by enhanced de-epoxidation of violaxanthin and accumulation of Cbr, a protein homologous to early light inducible proteins (Elips) in plants. These proteins belong to the superfamily of chlorophyll a/b binding proteins. Two Dunaliella strains, D. bardawil and D. salina, were compared for these two responses under light in the UVA, blue, green and red spectral ranges. In D. bardawil, the two stress responses were similarly induced under UVA, blue or red light and to a lesser extent under green light. In D. salina, a similar spectral range dependence was exhibited for violaxanthin de-epoxidation. However, Cbr accumulated only under UVA or blue light but not under green or red light. A strong synergistic effect of a low dose of blue light superimposed on red light resulted in Cbr accumulation. These results reveal strain-specific differences in spectral range requirements of the two light-stress responses. In the two strains, violaxanthin de-epoxidation is triggered under photosynthetically-active spectral ranges but at least in D. salina, Cbr accumulation appears to require a specific light signal additionally to a signal(s) generated by light stress.

  8. 1.55-μm mode-locked quantum-dot lasers with 300 MHz frequency tuning range

    SciTech Connect

    Sadeev, T. Arsenijević, D.; Bimberg, D.; Franke, D.; Kreissl, J.; Künzel, H.

    2015-01-19

    Passive mode-locking of two-section quantum-dot mode-locked lasers grown by metalorganic vapor phase epitaxy on InP is reported. 1250-μm long lasers exhibit a wide tuning range of 300 MHz around the fundamental mode-locking frequency of 33.48 GHz. The frequency tuning is achieved by varying the reverse bias of the saturable absorber from 0 to −2.2 V and the gain section current from 90 to 280 mA. 3 dB optical spectra width of 6–7 nm leads to ex-facet optical pulses with full-width half-maximum down to 3.7 ps. Single-section quantum-dot mode-locked lasers show 0.8 ps broad optical pulses after external fiber-based compression. Injection current tuning from 70 to 300 mA leads to 30 MHz frequency tuning.

  9. Hybrid-Mode-Assisted Long-Distance Excitation of Short-Range Surface Plasmons in a Nanotip-Enhanced Step-Index Fiber.

    PubMed

    Tuniz, Alessandro; Chemnitz, Mario; Dellith, Jan; Weidlich, Stefan; Schmidt, Markus A

    2017-02-08

    We propose and experimentally demonstrate a monolithic nanowire-enhanced fiber-based nanoprobe for the broadband delivery of light (550-730 nm) to a deep subwavelength scale using short-range surface plasmons. The geometry is formed by a step index fiber with an integrated gold nanowire in its core and a protruding gold nanotip with sub-10 nm apex radius. We present a novel coupling scheme to excite short-range surface plasmons, whereby the radially polarized hybrid mode propagating inside the nanowire section excites the plasmonic mode close to the fiber endface, which is in turn superfocused down to nanoscale dimensions at the tip apex. We show that in this all-integrated fiber-plasmonic coupling scheme the wire length can be orders of magnitude longer than the attenuation length of short-range plasmon polaritons, yielding a broadband plasmon excitation and reducing demands in fabrication. We observe that the scattered light in the far-field from the nanotip is axially polarized and preferentially excited by a radially polarized input, unambiguously revealing that it originates from a short-range plasmon propagating on the nanotip, in agreement with simulations. This novel excitation scheme will have important applications in near-field microscopy and nanophotonics and potentially offers significantly improved resolution compared to current delivery near-field probes.

  10. Liquid-phase epitaxy grown PbSnTe distributed feedback laser diodes with broad continuous single-mode tuning range

    NASA Technical Reports Server (NTRS)

    Hsieh, H.-H.; Fonstad, C. G.

    1980-01-01

    Distributed feedback (DFB) pulsed laser operation has been demonstrated in stripe geometry Pb(1-x)Sn(x)Te double-heterostructures grown by liquid-phase epitaxy. The grating structure of 0.79 micron periodicity operates in first order near 12.8 microns and was fabricated prior to the liquid-phase epitaxial growth using holographic exposure techniques. These DFB lasers had moderate thresholds, 3.6 kA/sq cm, and the output power versus current curves exhibited a sharp turn-on free of kinks. Clean, single-mode emission spectra, continuously tunable over a range in excess of 20 per cm, centered about 780 per cm (12.8 microns), and at an average rate of 1.2 per cm-K from 9 to 26 K, were observed. While weaker modes could at times be seen in the spectrum, substantially single-mode operation was obtained over the entire operating range and to over 10 times threshold.

  11. Impressive Transmission Mode Electromagnetic Interference Shielding Parameters of Graphene-like Nanocarbon/Polyurethane Nanocomposites for Short Range Tracking Countermeasures.

    PubMed

    Kumar, Arvind; Alegaonkar, Prashant S

    2015-07-15

    Shielding the microwave signature (8.2-12.4 GHz, X-band) of a locked in target is a tactically important electronic countermeasure. Herein, we report on mitigation in X-band transmission mode shielding parameters for polyurethane (PU), after incorporating graphene-like nanocarbon sheets (GNCs). Initially, PU and variable weight percent (1-25) GNCs/PU paste samples were subjected to Fourier transform infrared, Raman spectroscopy, and scanning electron microscopy. These samples were molded into toroidal shaped specimens by adiabatic hot-pressing technique, for microwave scattering measurements. Parameters, such as complex permittivity (ϵ'-jϵ″), alternating current (ac) conductivity, skin thickness, transmission (S21), effective transmission loss (SET), and shielding effectiveness were determined, in addition to direct current (dc) conductivity. The real and imaginary components are increased, respectively, by ∼5 and ∼30 times, whereas loss tangent, by ∼7, at 25 wt % loading of GNCs. The ac conductivity is enhanced from 0.248 (PU) to 7.288 S/m (25 wt %) by maximizing transmission loss to -26.45 dB (99.9%) and minimizing thickness to 1-2 mm. The dc percolation threshold is found to be low at ∼5 wt %, indicating superior dispersibility of GNCs, thereafter. In analysis, the atomic polarization (at ∼10 GHz) associated with the aromatic urethane amide rings acts as a backbone to engage incident electromagnetic field wiggles. The coupling occurs via charge transfer polarization currents at doubly bonded nitrogen, oxygen, and hydrosorpted sp3 carbon sites in GNCs. The field-matter interaction is dominant at the microvoid skin interface between GNCs and PU. Possible polarization mechanism is explained. The GNCs/PU nanocomposites are realized as an effective electromagnetic interference shielding block in the tracking band. The details are presented.

  12. Observation of ion cyclotron range of frequencies mode conversion plasma flow drive on Alcator C-Moda)

    NASA Astrophysics Data System (ADS)

    Lin, Y.; Rice, J. E.; Wukitch, S. J.; Greenwald, M. J.; Hubbard, A. E.; Ince-Cushman, A.; Lin, L.; Marmar, E. S.; Porkolab, M.; Reinke, M. L.; Tsujii, N.; Wright, J. C.; Alcator C-Mod Team

    2009-05-01

    At modest H3e levels (n3He/ne˜8%-12%), in relatively low density D(H3e) plasmas, n¯e≤1.3×1020 m-3, heated with 50 MHz rf power at Bt0˜5.1 T, strong (up to 90 km/s) toroidal rotation (Vϕ) in the cocurrent direction has been observed by high-resolution x-ray spectroscopy on Alcator C-Mod. The change in central Vϕ scales with the applied rf power (≤30 km s-1 MW-1), and is generally at least a factor of 2 higher than the empirically determined intrinsic plasma rotation scaling. The rotation in the inner plasma (r /a≤0.3) responds to the rf power more quickly than that of the outer region (r /a≥0.7), and the rotation profile is broadly peaked for r /a≤0.5. Localized poloidal rotation (0.3≤r/a≤0.6) in the ion diamagnetic drift direction (˜2 km/s at 3 MW) is also observed, and similarly increases with rf power. Changing the toroidal phase of the antenna does not affect the rotation direction, and it only weakly affects the rotation magnitude. The mode converted ion cyclotron wave (MC ICW) has been detected by a phase contrast imaging system and the MC process is confirmed by two-dimensional full wave TORIC simulations. The simulations also show that the MC ICW is strongly damped on H3e ions in the vicinity of the MC layer, approximately on the same flux surfaces where the rf driven flow is observed. The flow shear in our experiment is marginally sufficient for plasma confinement enhancement based on the comparison of the E ×B shearing rate and gyrokinetic linear stability analysis.

  13. Using tri-axial acceleration data to identify behavioral modes of free-ranging animals: general concepts and tools illustrated for griffon vultures.

    PubMed

    Nathan, Ran; Spiegel, Orr; Fortmann-Roe, Scott; Harel, Roi; Wikelski, Martin; Getz, Wayne M

    2012-03-15

    Integrating biomechanics, behavior and ecology requires a mechanistic understanding of the processes producing the movement of animals. This calls for contemporaneous biomechanical, behavioral and environmental data along movement pathways. A recently formulated unifying movement ecology paradigm facilitates the integration of existing biomechanics, optimality, cognitive and random paradigms for studying movement. We focus on the use of tri-axial acceleration (ACC) data to identify behavioral modes of GPS-tracked free-ranging wild animals and demonstrate its application to study the movements of griffon vultures (Gyps fulvus, Hablizl 1783). In particular, we explore a selection of nonlinear and decision tree methods that include support vector machines, classification and regression trees, random forest methods and artificial neural networks and compare them with linear discriminant analysis (LDA) as a baseline for classifying behavioral modes. Using a dataset of 1035 ground-truthed ACC segments, we found that all methods can accurately classify behavior (80-90%) and, as expected, all nonlinear methods outperformed LDA. We also illustrate how ACC-identified behavioral modes provide the means to examine how vulture flight is affected by environmental factors, hence facilitating the integration of behavioral, biomechanical and ecological data. Our analysis of just over three-quarters of a million GPS and ACC measurements obtained from 43 free-ranging vultures across 9783 vulture-days suggests that their annual breeding schedule might be selected primarily in response to seasonal conditions favoring rising-air columns (thermals) and that rare long-range forays of up to 1750 km from the home range are performed despite potentially heavy energetic costs and a low rate of food intake, presumably to explore new breeding, social and long-term resource location opportunities.

  14. Using tri-axial acceleration data to identify behavioral modes of free-ranging animals: general concepts and tools illustrated for griffon vultures

    PubMed Central

    Nathan, Ran; Spiegel, Orr; Fortmann-Roe, Scott; Harel, Roi; Wikelski, Martin; Getz, Wayne M.

    2012-01-01

    Summary Integrating biomechanics, behavior and ecology requires a mechanistic understanding of the processes producing the movement of animals. This calls for contemporaneous biomechanical, behavioral and environmental data along movement pathways. A recently formulated unifying movement ecology paradigm facilitates the integration of existing biomechanics, optimality, cognitive and random paradigms for studying movement. We focus on the use of tri-axial acceleration (ACC) data to identify behavioral modes of GPS-tracked free-ranging wild animals and demonstrate its application to study the movements of griffon vultures (Gyps fulvus, Hablizl 1783). In particular, we explore a selection of nonlinear and decision tree methods that include support vector machines, classification and regression trees, random forest methods and artificial neural networks and compare them with linear discriminant analysis (LDA) as a baseline for classifying behavioral modes. Using a dataset of 1035 ground-truthed ACC segments, we found that all methods can accurately classify behavior (80–90%) and, as expected, all nonlinear methods outperformed LDA. We also illustrate how ACC-identified behavioral modes provide the means to examine how vulture flight is affected by environmental factors, hence facilitating the integration of behavioral, biomechanical and ecological data. Our analysis of just over three-quarters of a million GPS and ACC measurements obtained from 43 free-ranging vultures across 9783 vulture-days suggests that their annual breeding schedule might be selected primarily in response to seasonal conditions favoring rising-air columns (thermals) and that rare long-range forays of up to 1750 km from the home range are performed despite potentially heavy energetic costs and a low rate of food intake, presumably to explore new breeding, social and long-term resource location opportunities. PMID:22357592

  15. Acute sensitivity of a broad range of freshwater mussels to chemicals with different modes of toxic action.

    PubMed

    Wang, Ning; Ivey, Christopher D; Ingersoll, Christopher G; Brumbaugh, William G; Alvarez, David; Hammer, Edward J; Bauer, Candice R; Augspurger, Tom; Raimondo, Sandy; Barnhart, M Christopher

    2017-03-01

    Freshwater mussels, one of the most imperiled groups of animals in the world, are generally underrepresented in toxicity databases used for the development of ambient water quality criteria and other environmental guidance values. Acute 96-h toxicity tests were conducted to evaluate the sensitivity of 5 species of juvenile mussels from 2 families and 4 tribes to 10 chemicals (ammonia, metals, major ions, and organic compounds) and to screen 10 additional chemicals (mainly organic compounds) with a commonly tested mussel species, fatmucket (Lampsilis siliquoidea). In the multi-species study, median effect concentrations (EC50s) among the 5 species differed by a factor of ≤2 for chloride, potassium, sulfate, and zinc; a factor of ≤5 for ammonia, chromium, copper, and nickel; and factors of 6 and 12 for metolachlor and alachlor, respectively, indicating that mussels representing different families or tribes had similar sensitivity to most of the tested chemicals, regardless of modes of action. There was a strong linear relationship between EC50s for fatmucket and the other 4 mussel species across the 10 chemicals (r(2)  = 0.97, slope close to 1.0), indicating that fatmucket was similar to other mussel species; thus, this commonly tested species can be a good surrogate for protecting other mussels in acute exposures. The sensitivity of juvenile fatmucket among different populations or cultured from larvae of wild adults and captive-cultured adults was also similar in acute exposures to copper or chloride, indicating captive-cultured adult mussels can reliably be used to reproduce juveniles for toxicity testing. In compiled databases for all freshwater species, 1 or more mussel species were among the 4 most sensitive species for alachlor, ammonia, chloride, potassium, sulfate, copper, nickel, and zinc; therefore, the development of water quality criteria and other environmental guidance values for these chemicals should reflect the sensitivity of mussels. In

  16. Acute sensitivity of a broad range of freshwater mussels to chemicals with different modes of toxic action

    USGS Publications Warehouse

    Wang, Ning; Ivey, Chris D.; Ingersoll, Christopher G.; Brumbaugh, William G.; Alvarez, David; Hammer, Edward J.; Bauer, Candice R.; Augspurger, Tom; Raimondo, Sandy; Barnhart, M.Christopher

    2017-01-01

    Freshwater mussels, one of the most imperiled groups of animals in the world, are generally underrepresented in toxicity databases used for the development of ambient water quality criteria and other environmental guidance values. Acute 96-h toxicity tests were conducted to evaluate the sensitivity of 5 species of juvenile mussels from 2 families and 4 tribes to 10 chemicals (ammonia, metals, major ions, and organic compounds) and to screen 10 additional chemicals (mainly organic compounds) with a commonly tested mussel species, fatmucket (Lampsilis siliquoidea). In the multi-species study, median effect concentrations (EC50s) among the 5 species differed by a factor of ≤2 for chloride, potassium, sulfate, and zinc; a factor of ≤5 for ammonia, chromium, copper, and nickel; and factors of 6 and 12 for metolachlor and alachlor, respectively, indicating that mussels representing different families or tribes had similar sensitivity to most of the tested chemicals, regardless of modes of action. There was a strong linear relationship between EC50s for fatmucket and the other 4 mussel species across the 10 chemicals (r2 = 0.97, slope close to 1.0), indicating that fatmucket was similar to other mussel species; thus, this commonly tested species can be a good surrogate for protecting other mussels in acute exposures. The sensitivity of juvenile fatmucket among different populations or cultured from larvae of wild adults and captive-cultured adults was also similar in acute exposures to copper or chloride, indicating captive-cultured adult mussels can reliably be used to reproduce juveniles for toxicity testing. In compiled databases for all freshwater species, 1 or more mussel species were among the 4 most sensitive species for alachlor, ammonia, chloride, potassium, sulfate, copper, nickel, and zinc; therefore, the development of water quality criteria and other environmental guidance values for these chemicals should reflect the sensitivity of mussels. In

  17. Accumulate-Repeat-Accumulate-Accumulate-Codes

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Dolinar, Sam; Thorpe, Jeremy

    2004-01-01

    Inspired by recently proposed Accumulate-Repeat-Accumulate (ARA) codes [15], in this paper we propose a channel coding scheme called Accumulate-Repeat-Accumulate-Accumulate (ARAA) codes. These codes can be seen as serial turbo-like codes or as a subclass of Low Density Parity Check (LDPC) codes, and they have a projected graph or protograph representation; this allows for a high-speed iterative decoder implementation using belief propagation. An ARAA code can be viewed as a precoded Repeat-and-Accumulate (RA) code with puncturing in concatenation with another accumulator, where simply an accumulator is chosen as the precoder; thus ARAA codes have a very fast encoder structure. Using density evolution on their associated protographs, we find examples of rate-lJ2 ARAA codes with maximum variable node degree 4 for which a minimum bit-SNR as low as 0.21 dB from the channel capacity limit can be achieved as the block size goes to infinity. Such a low threshold cannot be achieved by RA or Irregular RA (IRA) or unstructured irregular LDPC codes with the same constraint on the maximum variable node degree. Furthermore by puncturing the accumulators we can construct families of higher rate ARAA codes with thresholds that stay close to their respective channel capacity thresholds uniformly. Iterative decoding simulation results show comparable performance with the best-known LDPC codes but with very low error floor even at moderate block sizes.

  18. Validation of full-wave simulations for mode conversion of waves in the ion cyclotron range of frequencies with phase contrast imaging in Alcator C-Mod

    SciTech Connect

    Tsujii, N.; Porkolab, M.; Bonoli, P. T.; Edlund, E. M.; Ennever, P. C.; Lin, Y.; Wright, J. C.; Wukitch, S. J.; Jaeger, E. F.; Green, D. L.; Harvey, R. W.

    2015-08-15

    Mode conversion of fast waves in the ion cyclotron range of frequencies (ICRF) is known to result in current drive and flow drive under optimised conditions, which may be utilized to control plasma profiles and improve fusion plasma performance. To describe these processes accurately in a realistic toroidal geometry, numerical simulations are essential. Quantitative comparison of these simulations and the actual experimental measurements is important to validate their predictions and to evaluate their limitations. The phase contrast imaging (PCI) diagnostic has been used to directly detect the ICRF waves in the Alcator C-Mod tokamak. The measurements have been compared with full-wave simulations through a synthetic diagnostic technique. Recently, the frequency response of the PCI detector array on Alcator C-Mod was recalibrated, which greatly improved the comparison between the measurements and the simulations. In this study, mode converted waves for D-{sup 3}He and D-H plasmas with various ion species compositions were re-analyzed with the new calibration. For the minority heating cases, self-consistent electric fields and a minority ion distribution function were simulated by iterating a full-wave code and a Fokker-Planck code. The simulated mode converted wave intensity was in quite reasonable agreement with the measurements close to the antenna, but discrepancies remain for comparison at larger distances.

  19. Accumulate-Repeat-Accumulate-Accumulate Codes

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Dolinar, Samuel; Thorpe, Jeremy

    2007-01-01

    Accumulate-repeat-accumulate-accumulate (ARAA) codes have been proposed, inspired by the recently proposed accumulate-repeat-accumulate (ARA) codes. These are error-correcting codes suitable for use in a variety of wireless data-communication systems that include noisy channels. ARAA codes can be regarded as serial turbolike codes or as a subclass of low-density parity-check (LDPC) codes, and, like ARA codes they have projected graph or protograph representations; these characteristics make it possible to design high-speed iterative decoders that utilize belief-propagation algorithms. The objective in proposing ARAA codes as a subclass of ARA codes was to enhance the error-floor performance of ARA codes while maintaining simple encoding structures and low maximum variable node degree.

  20. A 10Gb/s APD-based linear burst-mode receiver with 31dB dynamic range for reach-extended PON systems.

    PubMed

    Yin, Xin; Moeneclaey, Bart; Qiu, Xing-Zhi; Verbrugghe, Jochen; Verheyen, Koen; Bauwelinck, Johan; Vandewege, Jan; Achouche, Mohand; Chang, Y

    2012-12-10

    We present for the first time a high performance APD-based linear burst-mode receiver (BM-RX) with a record wide dynamic range of 31 dB. The APD multiplication factor is controlled from burst to burst within 60 ns by an on-chip self-generated M-control signal. In the experiment, a total optical budget of 54 dB is achieved with a single SOA-based reach extender for 10 Gb/s upstream. With electronic dispersion compensation, the APD linear BM-RX with a wide dynamic range relaxes the requirement on optical components and lowers the system cost, especially at the optical network unit (ONU) side.

  1. DC-coupled burst-mode receiver with high sensitivity, wide dynamic range and short settling time for symmetric 10G-GPONs.

    PubMed

    Put, Jasmien; Yin, Xin; Qiu, Xing-Zhi; Gillis, Jan; Verbrugghe, Jochen; Bauwelinck, Johan; Vandewege, Jan; Blache, Fabrice; Lanteri, Delphine; Achouche, Mohand; Krimmel, Heinz-Georg; van Veen, Dora; Vetter, Peter

    2011-12-12

    This paper presents a high performance DC-coupled 10 Gbit/s APD-based optical burst-mode receiver (BM-RX) for symmetric 10G-GPONs. The BM-RX can handle upstream bursts with a loud/soft range wider than 24.0 dB, and the measured sensitivity is -30.0 dBm at BER = 10(-3) after a start of burst settling time no longer than 51 ns. This paper also investigates, for the first time, the inter-burst guard time required for a 10 Gbit/s BM-RX with auto-reset generation, while the PON operates upstream at a high raw BER and is using FEC.

  2. Pixel multiplexing technique for real-time three-dimensional-imaging laser detection and ranging system using four linear-mode avalanche photodiodes

    NASA Astrophysics Data System (ADS)

    Xu, Fan; Wang, Yuanqing; Li, Fenfang

    2016-03-01

    The avalanche-photodiode-array (APD-array) laser detection and ranging (LADAR) system has been continually developed owing to its superiority of nonscanning, large field of view, high sensitivity, and high precision. However, how to achieve higher-efficient detection and better integration of the LADAR system for real-time three-dimensional (3D) imaging continues to be a problem. In this study, a novel LADAR system using four linear mode APDs (LmAPDs) is developed for high-efficient detection by adopting a modulation and multiplexing technique. Furthermore, an automatic control system for the array LADAR system is proposed and designed by applying the virtual instrumentation technique. The control system aims to achieve four functions: synchronization of laser emission and rotating platform, multi-channel synchronous data acquisition, real-time Ethernet upper monitoring, and real-time signal processing and 3D visualization. The structure and principle of the complete system are described in the paper. The experimental results demonstrate that the LADAR system is capable of achieving real-time 3D imaging on an omnidirectional rotating platform under the control of the virtual instrumentation system. The automatic imaging LADAR system utilized only 4 LmAPDs to achieve 256-pixel-per-frame detection with by employing 64-bit demodulator. Moreover, the lateral resolution is ˜15 cm and range accuracy is ˜4 cm root-mean-square error at a distance of ˜40 m.

  3. Low threshold lasing of bubble-containing glass microspheres by non-whispering gallery mode excitation over a wide wavelength range

    SciTech Connect

    Kumagai, Tsutaru Kishi, Tetsuo; Yano, Tetsuji

    2015-03-21

    Bubble-containing Nd{sup 3+}-doped tellurite glass microspheres were fabricated by localized laser heating technique to investigate their optical properties for use as microresonators. Fluorescence and excitation spectra measurements were performed by pumping with a tunable CW-Ti:Sapphire laser. The excitation spectra manifested several sharp peaks due to the conventional whispering gallery mode (WGM) when the pumping laser was irradiated to the edge part of the microsphere. However, when the excitation light was irradiated on the bubble position inside the microsphere, “non-WGM excitation” was induced, giving rise to numerous peaks at a broad wavelength range in the excitation spectra. Thus, efficient excitation was achieved over a wide wavelength range. Lasing threshold excited at the bubble position was much lower than that for the excitation at the edges of the microsphere. The lowest value of the laser threshold was 34 μW for a 4 μm sphere containing a 0.5 μm bubble. Efficiency of the excitation at the bubble position with broadband light was calculated to be 5 times higher than that for the edge of the microsphere. The bubble-containing microsphere enables efficient utilization of broadband light excitation from light-emitting diodes and solar light.

  4. Higher growth temperatures decreased net carbon assimilation and biomass accumulation of northern red oak seedlings near the southern limit of the species range.

    PubMed

    Wertin, Timothy M; McGuire, Mary Anne; Teskey, Robert O

    2011-12-01

    increase in growth temperature, declining by 6% per 1 °C increase in mean growing season temperature. Our observations suggest that increases in air temperature above current ambient conditions will be detrimental to Q. rubra seedlings growing near the southern limit of the species range.

  5. Failure modes of electrospun nanofibers

    NASA Astrophysics Data System (ADS)

    Zussman, E.; Rittel, D.; Yarin, A. L.

    2003-06-01

    Failure modes of electrospun polymer nanofibers are reported. The nanofibers have diameters in the range of 80-400 nm and lengths greater then several centimeters. The nanofibers fail by a multiple necking mechanism, sometimes followed by the development of a fibriliar structure. This phenomenon is attributed to a strong stretching of solidified nanofibers by the tapered accumulating wheel (electrostatic lens), if its rotation speed becomes too high. Necking has not been observed in the nanofibers collected on a grounded plate.

  6. Operation of a New Half-Bridge Gate Driver for Enhancement - Mode GaN FETs, Type LM5113, Over a Wide Temperature Range

    NASA Technical Reports Server (NTRS)

    Patterson, Richard; Hammoud, Ahmad

    2011-01-01

    A new commercial-off-the-shelf (COTS) gate driver designed to drive both the high-side and the low-side enhancement-mode GaN FETs, National Semiconductor's type LM5113, was evaluated for operation at temperatures beyond its recommended specified limits of -40 C to +125 C. The effects of limited thermal cycling under the extended test temperature, which ranged from -194 C to +150 C, on the operation of this chip as well as restart capability at the extreme cryogenic and hot temperatures were also investigated. The driver circuit was able to maintain good operation throughout the entire test regime between -194 C and +150 C without undergoing any major changes in its outputs signals and characteristics. The limited thermal cycling performed on the device also had no effect on its performance, and the driver chip was able to successfully restart at each of the extreme temperatures of -194 C and +150 C. The plastic packaging of this device was also not affected by either the short extreme temperature exposure or the limited thermal cycling. These preliminary results indicate that this new commercial-off-the-shelf (COTS) halfbridge eGaN FET driver integrated circuit has the potential for use in space exploration missions under extreme temperature environments. Further testing is planned under long-term cycling to assess the reliability of these parts and to determine their suitability for extended use in the harsh environments of space.

  7. Effects of radio frequency fields in the lower hybrid range on temperature gradient driven drift-modes in tokamaks: Momentum and impurity transport

    NASA Astrophysics Data System (ADS)

    Das, Salil; Jhang, Hogun; Singh, R.; Nordman, H.

    2016-10-01

    The significant effect of impurities in radiation losses and plasma dilution, which result in lower fusion power, and the evaluation of the important effects of intrinsic rotation on transport barrier formation, determination of momentum pinch velocity and its theoretical basis, in tokamak performance is studied using the four-wave parametric process using an electrostatic, collisionless fluid model for ion-temperature-gradient and trapped-electron mode driven turbulence in the presence of radio frequency fields in the lower hybrid (LH) range of frequencies. The beating of the pump and the sidebands exert a ponderomotive force on electrons, modifying the eigenfrequency of the drift waves and influencing the growth rates and the turbulent transport properties. Explicit expressions for the non-linear growth rate and the associated ion thermal conductivity and effective impurity diffusivity are derived. The effects of the rf fields on the momentum and impurity transport coefficients are evaluated for key parameters like rf power, temperature gradients, and magnetic shear. Prince Georges Community College, Largo, Maryland 20774, USA.

  8. Insect-Specific Flaviviruses: A Systematic Review of Their Discovery, Host Range, Mode of Transmission, Superinfection Exclusion Potential and Genomic Organization

    PubMed Central

    Blitvich, Bradley J.; Firth, Andrew E.

    2015-01-01

    There has been a dramatic increase in the number of insect-specific flaviviruses (ISFs) discovered in the last decade. Historically, these viruses have generated limited interest due to their inability to infect vertebrate cells. This viewpoint has changed in recent years because some ISFs have been shown to enhance or suppress the replication of medically important flaviviruses in co-infected mosquito cells. Additionally, comparative studies between ISFs and medically important flaviviruses can provide a unique perspective as to why some flaviviruses possess the ability to infect and cause devastating disease in humans while others do not. ISFs have been isolated exclusively from mosquitoes in nature but the detection of ISF-like sequences in sandflies and chironomids indicates that they may also infect other dipterans. ISFs can be divided into two distinct phylogenetic groups. The first group currently consists of approximately 12 viruses and includes cell fusing agent virus, Kamiti River virus and Culex flavivirus. These viruses are phylogenetically distinct from all other known flaviviruses. The second group, which is apparently not monophyletic, currently consists of nine viruses and includes Chaoyang virus, Nounané virus and Lammi virus. These viruses phylogenetically affiliate with mosquito/vertebrate flaviviruses despite their apparent insect-restricted phenotype. This article provides a review of the discovery, host range, mode of transmission, superinfection exclusion ability and genomic organization of ISFs. This article also attempts to clarify the ISF nomenclature because some of these viruses have been assigned more than one name due to their simultaneous discoveries by independent research groups. PMID:25866904

  9. Accumulate Repeat Accumulate Coded Modulation

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    In this paper we propose an innovative coded modulation scheme called 'Accumulate Repeat Accumulate Coded Modulation' (ARA coded modulation). This class of codes can be viewed as serial turbo-like codes, or as a subclass of Low Density Parity Check (LDPC) codes that are combined with high level modulation. Thus at the decoder belief propagation can be used for iterative decoding of ARA coded modulation on a graph, provided a demapper transforms the received in-phase and quadrature samples to reliability of the bits.

  10. Low-Loss Coupling of Quantum Cascade Lasers into Hollow-Core Waveguides with Single-Mode Output in the 3.7-7.6 μm Spectral Range.

    PubMed

    Patimisco, Pietro; Sampaolo, Angelo; Mihai, Laura; Giglio, Marilena; Kriesel, Jason; Sporea, Dan; Scamarcio, Gaetano; Tittel, Frank K; Spagnolo, Vincenzo

    2016-04-13

    We demonstrated low-loss and single-mode laser beam delivery through hollow-core waveguides (HCWs) operating in the 3.7-7.6 μm spectral range. The employed HCWs have a circular cross section with a bore diameter of 200 μm and metallic/dielectric internal coatings deposited inside a glass capillary tube. The internal coatings have been produced to enhance the spectral response of the HCWs in the range 3.5-12 µm. We demonstrated Gaussian-like outputs throughout the 4.5-7.6 µm spectral range. A quasi single-mode output beam with only small beam distortions was achieved when the wavelength was reduced to 3.7 μm. With a 15-cm-long HCW and optimized coupling conditions, we measured coupling efficiencies of >88% and transmission losses of <1 dB in the investigated infrared spectral range.

  11. Low-Loss Coupling of Quantum Cascade Lasers into Hollow-Core Waveguides with Single-Mode Output in the 3.7–7.6 μm Spectral Range

    PubMed Central

    Patimisco, Pietro; Sampaolo, Angelo; Mihai, Laura; Giglio, Marilena; Kriesel, Jason; Sporea, Dan; Scamarcio, Gaetano; Tittel, Frank K.; Spagnolo, Vincenzo

    2016-01-01

    We demonstrated low-loss and single-mode laser beam delivery through hollow-core waveguides (HCWs) operating in the 3.7–7.6 μm spectral range. The employed HCWs have a circular cross section with a bore diameter of 200 μm and metallic/dielectric internal coatings deposited inside a glass capillary tube. The internal coatings have been produced to enhance the spectral response of the HCWs in the range 3.5–12 µm. We demonstrated Gaussian-like outputs throughout the 4.5–7.6 µm spectral range. A quasi single-mode output beam with only small beam distortions was achieved when the wavelength was reduced to 3.7 μm. With a 15-cm-long HCW and optimized coupling conditions, we measured coupling efficiencies of >88% and transmission losses of <1 dB in the investigated infrared spectral range. PMID:27089343

  12. Very large arrays of individually addressable high-power single-mode laser arrays in the 800- to 1000-nm wavelength range obtained by quantum well intermixing techniques

    NASA Astrophysics Data System (ADS)

    Najda, Stephen P.; Bacchin, Gianluca; Qiu, Bocang C.; Smith, Chris J. M.; Vassalli, O.; Toury, Marion; McDougall, Stewart D.; Hamilton, Craig J.; Marsh, John H.

    2005-04-01

    Quantum well intermixing (QWI) of the facet regions of a semiconductor laser can significantly improve the COD of the device giving high kink power and high reliability. A novel epitaxy design incorporating a graded 'V-profile' layer allows for a reduced vertical far-field and simultaneously suppresses higher order modes to give high power operation. Furthermore, the 'V-profile' layer provides a robust design to improve the ridge etch tolerance to give excellent device performance uniformity across an array. Very large arrays of individually addressable lasers (up to 100 elements) are reported with small pitch size (~100 μm), high single mode power (up to 300 mW) and high uniformity.

  13. Experimental demonstration of change of dynamical properties of a passively mode-locked semiconductor laser subject to dual optical feedback by dual full delay-range tuning.

    PubMed

    Nikiforov, O; Jaurigue, L; Drzewietzki, L; Lüdge, K; Breuer, S

    2016-06-27

    In this contribution we experimentally demonstrate the change and improvement of dynamical properties of a passively mode-locked semiconductor laser subject to optical feedback from two external cavities by coupling the feedback pulses back into the gain segment. Hereby, we tune the full delay-phase of the pulse-to-pulse period of both external cavities separately and demonstrate the change of the repetition rate, timing jitter, multi-pulse formation and side-band suppression for the first time for such a dual feedback configuration. In addition, we thereby confirm modeling predictions by achieving both a good qualitative and quantitative agreement of experimental and simulated results. Our findings suggest a path towards the realization of side-band free all-optical photonic oscillators based on mode-locked lasers.

  14. Different Mode of Afferents Determines the Frequency Range of High Frequency Activities in the Human Brain: Direct Electrocorticographic Comparison between Peripheral Nerve and Direct Cortical Stimulation

    PubMed Central

    Kobayashi, Katsuya; Matsumoto, Riki; Matsuhashi, Masao; Usami, Kiyohide; Shimotake, Akihiro; Kunieda, Takeharu; Kikuchi, Takayuki; Mikuni, Nobuhiro; Miyamoto, Susumu; Fukuyama, Hidenao; Takahashi, Ryosuke; Ikeda, Akio

    2015-01-01

    Physiological high frequency activities (HFA) are related to various brain functions. Factors, however, regulating its frequency have not been well elucidated in humans. To validate the hypothesis that different propagation modes (thalamo-cortical vs. cortico-coritcal projections), or different terminal layers (layer IV vs. layer II/III) affect its frequency, we, in the primary somatosensory cortex (SI), compared HFAs induced by median nerve stimulation with those induced by electrical stimulation of the cortex connecting to SI. We employed 6 patients who underwent chronic subdural electrode implantation for presurgical evaluation. We evaluated the HFA power values in reference to the baseline overriding N20 (earliest cortical response) and N80 (late response) of somatosensory evoked potentials (HFASEP(N20) and HFASEP(N80)) and compared those overriding N1 and N2 (first and second responses) of cortico-cortical evoked potentials (HFACCEP(N1) and HFACCEP(N2)). HFASEP(N20) showed the power peak in the frequency above 200 Hz, while HFACCEP(N1) had its power peak in the frequency below 200 Hz. Different propagation modes and/or different terminal layers seemed to determine HFA frequency. Since HFACCEP(N1) and HFA induced during various brain functions share a similar broadband profile of the power spectrum, cortico-coritcal horizontal propagation seems to represent common mode of neural transmission for processing these functions. PMID:26087042

  15. Different Mode of Afferents Determines the Frequency Range of High Frequency Activities in the Human Brain: Direct Electrocorticographic Comparison between Peripheral Nerve and Direct Cortical Stimulation.

    PubMed

    Kobayashi, Katsuya; Matsumoto, Riki; Matsuhashi, Masao; Usami, Kiyohide; Shimotake, Akihiro; Kunieda, Takeharu; Kikuchi, Takayuki; Mikuni, Nobuhiro; Miyamoto, Susumu; Fukuyama, Hidenao; Takahashi, Ryosuke; Ikeda, Akio

    2015-01-01

    Physiological high frequency activities (HFA) are related to various brain functions. Factors, however, regulating its frequency have not been well elucidated in humans. To validate the hypothesis that different propagation modes (thalamo-cortical vs. cortico-coritcal projections), or different terminal layers (layer IV vs. layer II/III) affect its frequency, we, in the primary somatosensory cortex (SI), compared HFAs induced by median nerve stimulation with those induced by electrical stimulation of the cortex connecting to SI. We employed 6 patients who underwent chronic subdural electrode implantation for presurgical evaluation. We evaluated the HFA power values in reference to the baseline overriding N20 (earliest cortical response) and N80 (late response) of somatosensory evoked potentials (HFA(SEP(N20)) and HFA(SEP(N80))) and compared those overriding N1 and N2 (first and second responses) of cortico-cortical evoked potentials (HFA(CCEP(N1)) and HFA(CCEP(N2))). HFA(SEP(N20)) showed the power peak in the frequency above 200 Hz, while HFA(CCEP(N1)) had its power peak in the frequency below 200 Hz. Different propagation modes and/or different terminal layers seemed to determine HFA frequency. Since HFA(CCEP(N1)) and HFA induced during various brain functions share a similar broadband profile of the power spectrum, cortico-coritcal horizontal propagation seems to represent common mode of neural transmission for processing these functions.

  16. Variation in Sulfur and Selenium Accumulation Is Controlled by Naturally Occurring Isoforms of the Key Sulfur Assimilation Enzyme ADENOSINE 5′-PHOSPHOSULFATE REDUCTASE2 across the Arabidopsis Species Range1[W][OPEN

    PubMed Central

    Chao, Dai-Yin; Baraniecka, Patrycja; Danku, John; Koprivova, Anna; Lahner, Brett; Luo, Hongbing; Yakubova, Elena; Dilkes, Brian; Kopriva, Stanislav; Salt, David E.

    2014-01-01

    Natural variation allows the investigation of both the fundamental functions of genes and their role in local adaptation. As one of the essential macronutrients, sulfur is vital for plant growth and development and also for crop yield and quality. Selenium and sulfur are assimilated by the same process, and although plants do not require selenium, plant-based selenium is an important source of this essential element for animals. Here, we report the use of linkage mapping in synthetic F2 populations and complementation to investigate the genetic architecture of variation in total leaf sulfur and selenium concentrations in a diverse set of Arabidopsis (Arabidopsis thaliana) accessions. We identify in accessions collected from Sweden and the Czech Republic two variants of the enzyme ADENOSINE 5′-PHOSPHOSULFATE REDUCTASE2 (APR2) with strongly diminished catalytic capacity. APR2 is a key enzyme in both sulfate and selenate reduction, and its reduced activity in the loss-of-function allele apr2-1 and the two Arabidopsis accessions Hodonín and Shahdara leads to a lowering of sulfur flux from sulfate into the reduced sulfur compounds, cysteine and glutathione, and into proteins, concomitant with an increase in the accumulation of sulfate in leaves. We conclude from our observation, and the previously identified weak allele of APR2 from the Shahdara accession collected in Tadjikistan, that the catalytic capacity of APR2 varies by 4 orders of magnitude across the Arabidopsis species range, driving significant differences in sulfur and selenium metabolism. The selective benefit, if any, of this large variation remains to be explored. PMID:25245030

  17. Coupling of Er light emissions to plasmon modes on In{sub 2}O{sub 3}: Sn nanoparticle sheets in the near-infrared range

    SciTech Connect

    Matsui, Hiroaki Tabata, Hitoshi; Badalawa, Wasanthamala; Nomura, Wataru; Yatsui, Takashi; Ohtsu, Motoichi; Hasebe, Takayuki; Furuta, Shinya

    2014-07-28

    Near-infrared Er photoluminescence (PL) is markedly modified using a plasmonic In{sub 2}O{sub 3}: Sn nanoparticle (NP) sheet. Modeling and optical measurements reveal the presence of different electric fields (E-field) in the NP sheet. The local E-field excited at the interface between the NP sheet and Er-emitting layer of ZnO contributes significantly towards the spectral modifications of Er PL due to matching with the photon energy of Er PL. We also determine the critical temperature for Er PL modifications, which is related to the energy transfer efficiency between Er transition dipoles in ZnO and the plasmon modes on the NP sheet.

  18. 3D models automatic reconstruction of selected close range objects. (Polish Title: Automatyczna rekonstrukcja modeli 3D małych obiektów bliskiego zasiegu)

    NASA Astrophysics Data System (ADS)

    Zaweiska, D.

    2013-12-01

    Reconstruction of three-dimensional, realistic models of objects from digital images has been the topic of research in many areas of science for many years. This development is stimulated by new technologies and tools, which appeared recently, such as digital photography, laser scanners, increase in the equipment efficiency and Internet. The objective of this paper is to present results of automatic modeling of selected close range objects, with the use of digital photographs acquired by the Hasselblad H4D50 camera. The author's software tool was utilized for calculations; it performs successive stages of the 3D model creation. The modeling process was presented as the complete process which starts from acquisition of images and which is completed by creation of a photorealistic 3D model in the same software environment. Experiments were performed for selected close range objects, with appropriately arranged image geometry, creating a ring around the measured object. The Area Base Matching (CC/LSM) method, the RANSAC algorithm, with the use of tensor calculus, were utilized form automatic matching of points detected with the SUSAN algorithm. Reconstruction of the surface of model generation is one of the important stages of 3D modeling. Reconstruction of precise surfaces, performed on the basis of a non-organized cloud of points, acquired from automatic processing of digital images, is a difficult task, which has not been finally solved. Creation of poly-angular models, which may meet high requirements concerning modeling and visualization is required in many applications. The polynomial method is usually the best way to precise representation of measurement results, and, at the same time, to achieving the optimum description of the surface. Three algorithm were tested: the volumetric method (VCG), the Poisson method and the Ball pivoting method. Those methods are mostly applied to modeling of uniform grids of points. Results of experiments proved that incorrect

  19. Comparison in gas media (absolute and gauge mode)in the range from 25 kPa TO 200 kPa (EURAMET.M.P-K8)

    NASA Astrophysics Data System (ADS)

    Wuethrich, C.; Alisic, S.; Altintas, A.; van Andel, I.; C, In­Mook; Eltawil, A. A.; Farár, P.; Hetherington, P.; Koçaş, I.; Lefkopoulos, A.; Otal, P.; Prazak, D.; Sabuga, W.; Salustiano, R.; Sandu, I.; Sardi, M.; Saxholm, S.; Setina, J.; Spohr, I.; Steindl, D.; Testa, N.; Vámossy, C.; Grgec Bermanec, L.

    2016-01-01

    It was decided at the EURAMET TC-M meeting in Torino in 2006 to realize a comparison in gauge and absolute pressure up to 200 kPa as it would allow a link to the CCM.P-K6 and CCM.P-K2 comparisons to be established. This project interested a lot of laboratories from the beginning with 23 participants, 22 of which have submitted results. The circulation of the transfer standard began in July 2009 and lasted until January 2012. No major problems occurred during the transport. The measurand of the comparison is the effective area of a piston-cylinder determined in gauge and absolute pressure from 25 kPa to 200 kPa with pressure steps of 25 kPa. The transfer standard is a gas lubricated tungsten carbide piston-cylinder with an effective area of ~9.8 cm2, fabricated by DH Instruments and compatible with a PG-7601 pressure balance. Some participants used their own pressure balance while a pressure balance with a reference vacuum sensor has been circulated for the participants not equipped with this system. One participant (SMU, Slovakia) has never provided the measurement results and another participant (FORCE Technology, Denmark) submitted a revised set of measurement results after the pilot laboratory mentioned that the equivalence was not met. After the determination of the reference value, all the 22 participants who delivered the results in gauge pressure demonstrated equivalence respective to the reference value on most of the range. In absolute pressure the equivalence is demonstrated, for all nominal pressures, by all 17 participants who submitted results. The comparison is linked to the CCM.P-K6 for gauge pressure and to CCM.P-K2 for absolute pressure. The link does not strongly affect the equivalence of the results and an excellent degree of equivalence is achieved in gauge and absolute pressure. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb

  20. Proline accumulation in plants: a review.

    PubMed

    Verbruggen, Nathalie; Hermans, Christian

    2008-11-01

    Proline (Pro) accumulation is a common physiological response in many plants in response to a wide range of biotic and abiotic stresses. Controversy has surrounded the possible role(s) of proline accumulation. In this review, knowledge on the regulation of Pro metabolism during development and stress, results of genetic manipulation of Pro metabolism and current debate on Pro toxicity in plants are presented.

  1. Experimental Study of Top Heat Mode Thermosyphon

    NASA Astrophysics Data System (ADS)

    Hirashima, Masao; Kimura, Kenichiro; Utsumi, Yoichi; Kimura, Kenichi; Negishi, Kanji

    The purpose of this study is to develop the top heat mode thermosyphon that is very attractive means, for example, to accumulate directly the summer solar energy into the underground soil for the winter season. In this case, it can exclude the complex piping and mechanical pump to circulate the hot water absorbed the solar energy through the piping system buried in the soil layer. The several ideas concerning the top heat thermosyphon had been proposed, however, there were few reports on the definite experiments. The authors have carried out the experimental study of the top heat mode thermosyphon, with a simple lifting pipe, which could draw the working liquid from the under condenser to the upper evaporator section. The improvement of the main construction parts such as evaporator, lifting pipe, liquid reservoir trap and vapour nozzle have been performed in the present experiment in order to obtain the optimum operation range.

  2. Interplay of growth mode and thermally induced spin accumulation in epitaxial Al/Co2TiSi/Al and Al/Co2TiGe/Al contacts

    NASA Astrophysics Data System (ADS)

    Geisler, Benjamin; Kratzer, Peter; Popescu, Voicu

    2014-05-01

    The feasibility of thermally driven spin injectors built from half-metallic Heusler alloys inserted between Al leads was investigated by means of ab initio calculations of the thermodynamic stability and electronic transport. We have focused on two main issues and found that (i) the interface between Al and the closely lattice-matched Heusler alloys of type Co2TiZ (Z = Si or Ge) is stable under various growth conditions; and (ii) the conventional and spin-dependent Seebeck coefficients in such heterojunctions exhibit a strong dependence on both the spacer and the atomic composition of the Al/Heusler interface. The latter quantity gives a measure of the spin accumulation and varies between +8 and -3 μV/K near 300 K, depending on whether a Ti-Ge or a Co-Co plane makes the contact between Al and Co2TiGe in the trilayer. Our results show that it is in principle possible to tailor the spin-caloric effects by a targeted growth control of the samples.

  3. Dual-Mode Combustor

    NASA Technical Reports Server (NTRS)

    Trefny, Charles J (Inventor); Dippold, Vance F (Inventor)

    2013-01-01

    A new dual-mode ramjet combustor used for operation over a wide flight Mach number range is described. Subsonic combustion mode is usable to lower flight Mach numbers than current dual-mode scramjets. High speed mode is characterized by supersonic combustion in a free-jet that traverses the subsonic combustion chamber to a variable nozzle throat. Although a variable combustor exit aperture is required, the need for fuel staging to accommodate the combustion process is eliminated. Local heating from shock-boundary-layer interactions on combustor walls is also eliminated.

  4. Integrated mode converter for mode division multiplexing

    NASA Astrophysics Data System (ADS)

    Perez-Galacho, Diego; Alonso-Ramos, Carlos Alberto; Marris-Morini, Delphine; Vakarin, Vladyslav; Le Roux, Xavier; Ortega-Moñux, Alejandro; Wangüemert-Perez, Juan Gonzalo; Vivien, Laurent

    2016-05-01

    The ever growing demands of bandwidth in optical communication systems are making traditional Wavelength Division Multiplexing (WDM) based systems to reach its limit. In order to cope with future bandwidth demand is necessary to use new levels of orthogonality, such as the waveguide mode or the polarization state. Mode Division Multiplexing (MDM) has recently attracted attention as a possible solution to increase aggregate bandwidth. In this work we discuss the proposition a of mode converter that can cover the whole C-Band of optical communications. The Mode Converter is based on two Multimode Interference (MMI) couplers and a phase shifter. Insertion loss (IL) below 0.2 dB and Extinction ratio (ER) higher than 20 dB in a broad bandwidth range of 1.5 μm to 1.6 μm have been estimated. The total length of the device is less than 30 μm.

  5. Connection between the Weakly Coherent Mode and particle transport across the LCFS in the I-mode

    NASA Astrophysics Data System (ADS)

    Dominguez, A.; Marmar, E. S.; Terry, J. L.; Labombard, B.; Greenwald, M.; Hubbard, A. E.; Hughes, J. W.; Kramer, G. J.; White, A. E.; Whyte, D. G.

    2012-10-01

    The I-mode regime is characterized by the formation of ion and electron temperature pedestals, while maintaining L-mode-like radial density profiles [1]. Changes in edge density, temperature and magnetic field fluctuations accompany the L-mode to I-mode transition with reduction of fluctuations in the 50-150kHz range as well as the appearance of a Weakly Coherent Mode (WCM) in the 150-300kHz range. Previous work[2] has established a connection between the midrange fluctuation reduction and a decrease in the effective thermal diffusivity in the pedestal region. The mechanism for maintaining sufficient particle transport to avoid impurity accumulation has been unclear. In this work, quantitative comparisons are made between particle transport measurements across the LCFS and the intensity of the WCM in the I-mode. The particle transport has been estimated using Dα profiles measured near the outboard midplane and the intensity of the WCM is obtained by spectral analysis of density fluctuations from reflectometry. The measurements show correlations between the particle transport and the WCM intensity, supporting evidence that the WCM causes enhanced transport.[4pt] [1] D.G. Whyte, et al., Nucl. Fusion 50 (2010)105005.[0pt] [2] A.E. Hubbard, et al., Phys. Plasmas 18(2011)056115

  6. Bacterial accumulation in viscosity gradients

    NASA Astrophysics Data System (ADS)

    Waisbord, Nicolas; Guasto, Jeffrey

    2016-11-01

    Cell motility is greatly modified by fluid rheology. In particular, the physical environments in which cells function, are often characterized by gradients of viscous biopolymers, such as mucus and extracellular matrix, which impact processes ranging from reproduction to digestion to biofilm formation. To understand how spatial heterogeneity of fluid rheology affects the motility and transport of swimming cells, we use hydrogel microfluidic devices to generate viscosity gradients in a simple, polymeric, Newtonian fluid. Using video microscopy, we characterize the random walk motility patterns of model bacteria (Bacillus subtilis), showing that both wild-type ('run-and-tumble') cells and smooth-swimming mutants accumulate in the viscous region of the fluid. Through statistical analysis of individual cell trajectories and body kinematics in both homogeneous and heterogeneous viscous environments, we discriminate passive, physical effects from active sensing processes to explain the observed cell accumulation at the ensemble level.

  7. A True Eddy Accumulation - Eddy Covariance hybrid for measurements of turbulent trace gas fluxes

    NASA Astrophysics Data System (ADS)

    Siebicke, Lukas

    2016-04-01

    Eddy covariance (EC) is state-of-the-art in directly and continuously measuring turbulent fluxes of carbon dioxide and water vapor. However, low signal-to-noise ratios, high flow rates and missing or complex gas analyzers limit it's application to few scalars. True eddy accumulation, based on conditional sampling ideas by Desjardins in 1972, requires no fast response analyzers and is therefore potentially applicable to a wider range of scalars. Recently we showed possibly the first successful implementation of True Eddy Accumulation (TEA) measuring net ecosystem exchange of carbon dioxide of a grassland. However, most accumulation systems share the complexity of having to store discrete air samples in physical containers representing entire flux averaging intervals. The current study investigates merging principles of eddy accumulation and eddy covariance, which we here refer to as "true eddy accumulation in transient mode" (TEA-TM). This direct flux method TEA-TM combines true eddy accumulation with continuous sampling. The TEA-TM setup is simpler than discrete accumulation methods while avoiding the need for fast response gas analyzers and high flow rates required for EC. We implemented the proposed TEA-TM method and measured fluxes of carbon dioxide (CO2), methane (CH4) and water vapor (H2O) above a mixed beech forest at the Hainich Fluxnet and ICOS site, Germany, using a G2301 laser spectrometer (Picarro Inc., USA). We further simulated a TEA-TM sampling system using measured high frequency CO2 time series from an open-path gas analyzer. We operated TEA-TM side-by-side with open-, enclosed- and closed-path EC flux systems for CO2, H2O and CH4 (LI-7500, LI-7200, LI-6262, LI-7700, Licor, USA, and FGGA LGR, USA). First results show that TEA-TM CO2 fluxes were similar to EC fluxes. Remaining differences were similar to those between the three eddy covariance setups (open-, enclosed- and closed-path gas analyzers). Measured TEA-TM CO2 fluxes from our physical

  8. Passive Ranging

    DTIC Science & Technology

    1988-08-01

    1981). 5. R. Courant and D. Hilbert, Methods of Mathematical Physics , Vol. I, English ed., * Interscience, New York, 1953. 32 32 APPENDIX A CALCULATION...K Courant and D. Hilbert, Methods of Mathematical Physics , Vol. I, English ed., * Interscience, New York, 1953. A-8 APPENDIX B * RANGING ACCURACY IN

  9. Comprehensive model of damage accumulation in silicon

    SciTech Connect

    Mok, K. R. C.; Benistant, F.; Jaraiz, M.; Rubio, J. E.; Castrillo, P.; Pinacho, R.; Srinivasan, M. P.

    2008-01-01

    Ion implantation induced damage accumulation is crucial to the simulation of silicon processing. We present a physically based damage accumulation model, implemented in a nonlattice atomistic kinetic Monte Carlo simulator, that can simulate a diverse range of interesting experimental observations. The model is able to reproduce the ion-mass dependent silicon amorphous-crystalline transition temperature of a range of ions from C to Xe, the amorphous layer thickness for a range of amorphizing implants, the superlinear increase in damage accumulation with dose, and the two-layered damage distribution observed along the path of a high-energy ion. In addition, this model is able to distinguish between dynamic annealing and post-cryogenic implantation annealing, whereby dynamic annealing is more effective in removing damage than post-cryogenic implantation annealing at the same temperature.

  10. Mixed Mode Stable Tearing of Thin Sheet Al 6061-T6 Specimens: Experimental Measurements and Finite Element Simulations using a Modified Mohr-Coulomb Fracture Criterion

    DTIC Science & Technology

    2010-11-01

    grounding. Oliver (1996a,b), Teng (2008) andXue (2007a) reported on successful application of contin- uum damage mechanics in simulating initiation and...the accumulated damage should reach the critical value and the load carrying capacity must vanish in the post-initiate range. It should be noted that...specimen using fracture coupled with damage plastic- ity approach. Different from Mode I, little thickness reduction is observed for Mode III loading, as

  11. Chimpanzee accumulative stone throwing.

    PubMed

    Kühl, Hjalmar S; Kalan, Ammie K; Arandjelovic, Mimi; Aubert, Floris; D'Auvergne, Lucy; Goedmakers, Annemarie; Jones, Sorrel; Kehoe, Laura; Regnaut, Sebastien; Tickle, Alexander; Ton, Els; van Schijndel, Joost; Abwe, Ekwoge E; Angedakin, Samuel; Agbor, Anthony; Ayimisin, Emmanuel Ayuk; Bailey, Emma; Bessone, Mattia; Bonnet, Matthieu; Brazolla, Gregory; Buh, Valentine Ebua; Chancellor, Rebecca; Cipoletta, Chloe; Cohen, Heather; Corogenes, Katherine; Coupland, Charlotte; Curran, Bryan; Deschner, Tobias; Dierks, Karsten; Dieguez, Paula; Dilambaka, Emmanuel; Diotoh, Orume; Dowd, Dervla; Dunn, Andrew; Eshuis, Henk; Fernandez, Rumen; Ginath, Yisa; Hart, John; Hedwig, Daniela; Ter Heegde, Martijn; Hicks, Thurston Cleveland; Imong, Inaoyom; Jeffery, Kathryn J; Junker, Jessica; Kadam, Parag; Kambi, Mohamed; Kienast, Ivonne; Kujirakwinja, Deo; Langergraber, Kevin; Lapeyre, Vincent; Lapuente, Juan; Lee, Kevin; Leinert, Vera; Meier, Amelia; Maretti, Giovanna; Marrocoli, Sergio; Mbi, Tanyi Julius; Mihindou, Vianet; Moebius, Yasmin; Morgan, David; Morgan, Bethan; Mulindahabi, Felix; Murai, Mizuki; Niyigabae, Protais; Normand, Emma; Ntare, Nicolas; Ormsby, Lucy Jayne; Piel, Alex; Pruetz, Jill; Rundus, Aaron; Sanz, Crickette; Sommer, Volker; Stewart, Fiona; Tagg, Nikki; Vanleeuwe, Hilde; Vergnes, Virginie; Willie, Jacob; Wittig, Roman M; Zuberbuehler, Klaus; Boesch, Christophe

    2016-02-29

    The study of the archaeological remains of fossil hominins must rely on reconstructions to elucidate the behaviour that may have resulted in particular stone tools and their accumulation. Comparatively, stone tool use among living primates has illuminated behaviours that are also amenable to archaeological examination, permitting direct observations of the behaviour leading to artefacts and their assemblages to be incorporated. Here, we describe newly discovered stone tool-use behaviour and stone accumulation sites in wild chimpanzees reminiscent of human cairns. In addition to data from 17 mid- to long-term chimpanzee research sites, we sampled a further 34 Pan troglodytes communities. We found four populations in West Africa where chimpanzees habitually bang and throw rocks against trees, or toss them into tree cavities, resulting in conspicuous stone accumulations at these sites. This represents the first record of repeated observations of individual chimpanzees exhibiting stone tool use for a purpose other than extractive foraging at what appear to be targeted trees. The ritualized behavioural display and collection of artefacts at particular locations observed in chimpanzee accumulative stone throwing may have implications for the inferences that can be drawn from archaeological stone assemblages and the origins of ritual sites.

  12. Accumulation of the planets

    NASA Technical Reports Server (NTRS)

    Wetherill, G. W.

    1987-01-01

    In modeling the accumulation of planetesimals into planets, it is appropriate to distinguish between two stages: an early stage, during which approximately 10 km diameter planetesimals accumulate locally to form bodies approximate 10 to the 25th g in mass; and a later stage in which the approximately 10 to the 25th g planetesimals accumulate into the final planets. In the terrestrial planet region, an initial planetesimal swarm corresponding to the critical mass of dust layer gravitational instabilities is considered. In order to better understand the accumulation history of Mercury-sized bodies, 19 Monte-Carlo simulations of terrestrial planet growth were calculated. A Monte Carlo technique was used to investigate the orbital evolution of asteroidal collision debris produced interior to 2.6 AU. It was found that there are two regions primarily responsible for production of Earth-crossing meteoritic material and Apollo objects. The same techniques were extended to include the origin of Earth-approaching asteroidal bodies. It is found that these same two resonant mechanisms predict a steady-state number of Apollo-Amor about 1/2 that estimated based on astronomical observations.

  13. Chimpanzee accumulative stone throwing

    PubMed Central

    Kühl, Hjalmar S.; Kalan, Ammie K.; Arandjelovic, Mimi; Aubert, Floris; D’Auvergne, Lucy; Goedmakers, Annemarie; Jones, Sorrel; Kehoe, Laura; Regnaut, Sebastien; Tickle, Alexander; Ton, Els; van Schijndel, Joost; Abwe, Ekwoge E.; Angedakin, Samuel; Agbor, Anthony; Ayimisin, Emmanuel Ayuk; Bailey, Emma; Bessone, Mattia; Bonnet, Matthieu; Brazolla, Gregory; Buh, Valentine Ebua; Chancellor, Rebecca; Cipoletta, Chloe; Cohen, Heather; Corogenes, Katherine; Coupland, Charlotte; Curran, Bryan; Deschner, Tobias; Dierks, Karsten; Dieguez, Paula; Dilambaka, Emmanuel; Diotoh, Orume; Dowd, Dervla; Dunn, Andrew; Eshuis, Henk; Fernandez, Rumen; Ginath, Yisa; Hart, John; Hedwig, Daniela; Ter Heegde, Martijn; Hicks, Thurston Cleveland; Imong, Inaoyom; Jeffery, Kathryn J.; Junker, Jessica; Kadam, Parag; Kambi, Mohamed; Kienast, Ivonne; Kujirakwinja, Deo; Langergraber, Kevin; Lapeyre, Vincent; Lapuente, Juan; Lee, Kevin; Leinert, Vera; Meier, Amelia; Maretti, Giovanna; Marrocoli, Sergio; Mbi, Tanyi Julius; Mihindou, Vianet; Moebius, Yasmin; Morgan, David; Morgan, Bethan; Mulindahabi, Felix; Murai, Mizuki; Niyigabae, Protais; Normand, Emma; Ntare, Nicolas; Ormsby, Lucy Jayne; Piel, Alex; Pruetz, Jill; Rundus, Aaron; Sanz, Crickette; Sommer, Volker; Stewart, Fiona; Tagg, Nikki; Vanleeuwe, Hilde; Vergnes, Virginie; Willie, Jacob; Wittig, Roman M.; Zuberbuehler, Klaus; Boesch, Christophe

    2016-01-01

    The study of the archaeological remains of fossil hominins must rely on reconstructions to elucidate the behaviour that may have resulted in particular stone tools and their accumulation. Comparatively, stone tool use among living primates has illuminated behaviours that are also amenable to archaeological examination, permitting direct observations of the behaviour leading to artefacts and their assemblages to be incorporated. Here, we describe newly discovered stone tool-use behaviour and stone accumulation sites in wild chimpanzees reminiscent of human cairns. In addition to data from 17 mid- to long-term chimpanzee research sites, we sampled a further 34 Pan troglodytes communities. We found four populations in West Africa where chimpanzees habitually bang and throw rocks against trees, or toss them into tree cavities, resulting in conspicuous stone accumulations at these sites. This represents the first record of repeated observations of individual chimpanzees exhibiting stone tool use for a purpose other than extractive foraging at what appear to be targeted trees. The ritualized behavioural display and collection of artefacts at particular locations observed in chimpanzee accumulative stone throwing may have implications for the inferences that can be drawn from archaeological stone assemblages and the origins of ritual sites. PMID:26923684

  14. The accumulation and structure of comets

    NASA Technical Reports Server (NTRS)

    Donn, Bertram

    1991-01-01

    The paper reviews evidence for the accumulation of the terrestrial planets and comets from solid grains, with emphasis on the various proposals for the formation of cometary nuclei. With three exceptions, all hypotheses conclude or imply that a single compact object forms. Several hypotheses start with Goldreich-Ward-type gravitational instabilities. The collapse for this case also occurs at low velocities in the cm/s to m/s range. Experiment and theory show that under these conditions, low-density, filamentary clusters form that are fractal aggregates with a fractal dimension approximately equal to 2. In order to form cometary nuclei, the initial temperature must be about 50 K and not undergo a significant temperature rise during the accumulation process. The calculations show that accumulation will occur at low temperatures. Models of cometary nuclei are reviewed, and a simple model of the structure that results fom the accumulation of fluffy aggregates is described.

  15. Light impurity transport in I-mode in Alcator C-Mod

    NASA Astrophysics Data System (ADS)

    Rowan, W. L.; Bespamyatnov, I. O.; Hatch, D. R.; Horton, W. L.; Liao, K. T.

    2014-10-01

    The I-mode hallmarks are H-mode-like electron temperature pedestal and energy confinement simultaneous with L-mode-like density pedestal and particle confinement. The I-mode is observed over a wide range of plasma parameters and is robust. As might be expected from the particle confinement observation, accumulation of naturally-occuring impurities is reduced compared to H-mode. Heavy impurity measurements confirm the observation of L-mode-like particle confinement. In the results reported here for light impurities, I-mode impurity profiles are compared with both H- and L- mode profiles for helium and boron with an emphasis on core confinement. We search for the dependence of the impurity density gradient scale lengths on the main ion density scale length and temperature scale length, the Zeff the collisionality, as well as on total radiation loss, stored energy, and global confinement. The results allow comparisons among discharge modes, as well as comparison to other devices, and turbulence predictions. The data analysis is compared with gyrokinetic simulations using the GENE code. Supported by USDoE award DE-FG03-96ER-54373.

  16. Control of helium accumulation

    SciTech Connect

    Varadarajan, V.; Miley, G.H.

    1990-01-01

    The fishbone like oscillations in ignited tokamaks are addressed in an exploratory manner. The effects of the strong m = 1 oscillations and the weak high-frequency oscillations are examined in order to explore the feasibility of utilizing these oscillations for alpha accumulation control. The prospects of achieving small scale continuous alpha removal from the plasma center by mild fishbone-like oscillations are examined.

  17. Selenium accumulation by plants

    PubMed Central

    White, Philip J.

    2016-01-01

    Background Selenium (Se) is an essential mineral element for animals and humans, which they acquire largely from plants. The Se concentration in edible plants is determined by the Se phytoavailability in soils. Selenium is not an essential element for plants, but excessive Se can be toxic. Thus, soil Se phytoavailability determines the ecology of plants. Most plants cannot grow on seleniferous soils. Most plants that grow on seleniferous soils accumulate <100 mg Se kg–1 dry matter and cannot tolerate greater tissue Se concentrations. However, some plant species have evolved tolerance to Se, and commonly accumulate tissue Se concentrations >100 mg Se kg–1 dry matter. These plants are considered to be Se accumulators. Some species can even accumulate Se concentrations of 1000–15 000 mg Se kg–1 dry matter and are called Se hyperaccumulators. Scope This article provides an overview of Se uptake, translocation and metabolism in plants and highlights the possible genetic basis of differences in these between and within plant species. The review focuses initially on adaptations allowing plants to tolerate large Se concentrations in their tissues and the evolutionary origin of species that hyperaccumulate Se. It then describes the variation in tissue Se concentrations between and within angiosperm species and identifies genes encoding enzymes limiting the rates of incorporation of Se into organic compounds and chromosomal loci that might enable the development of crops with greater Se concentrations in their edible portions. Finally, it discusses transgenic approaches enabling plants to tolerate greater Se concentrations in the rhizosphere and in their tissues. Conclusions The trait of Se hyperaccumulation has evolved several times in separate angiosperm clades. The ability to tolerate large tissue Se concentrations is primarily related to the ability to divert Se away from the accumulation of selenocysteine and selenomethionine, which might be incorporated

  18. Heat exchanger-accumulator

    DOEpatents

    Ecker, Amir L.

    1980-01-01

    What is disclosed is a heat exchanger-accumulator for vaporizing a refrigerant or the like, characterized by an upright pressure vessel having a top, bottom and side walls; an inlet conduit eccentrically and sealingly penetrating through the top; a tubular overflow chamber disposed within the vessel and sealingly connected with the bottom so as to define an annular outer volumetric chamber for receiving refrigerant; a heat transfer coil disposed in the outer volumetric chamber for vaporizing the liquid refrigerant that accumulates there; the heat transfer coil defining a passageway for circulating an externally supplied heat exchange fluid; transferring heat efficiently from the fluid; and freely allowing vaporized refrigerant to escape upwardly from the liquid refrigerant; and a refrigerant discharge conduit penetrating sealingly through the top and traversing substantially the length of the pressurized vessel downwardly and upwardly such that its inlet is near the top of the pressurized vessel so as to provide a means for transporting refrigerant vapor from the vessel. The refrigerant discharge conduit has metering orifices, or passageways, penetrating laterally through its walls near the bottom, communicating respectively interiorly and exteriorly of the overflow chamber for controllably carrying small amounts of liquid refrigerant and oil to the effluent stream of refrigerant gas.

  19. Adaptive mode control in few mode fibers and its applications

    NASA Astrophysics Data System (ADS)

    Ashry, Islam; Lu, Peng; Xu, Yong

    2016-10-01

    With the development of mode-division-multiplexing (MDM), few mode fibers (FMFs) have found a wide range of applications in optical sensing and communications. However, how to precisely control the mode composition of optical signals in FMFs remains a difficult challenge. In this paper, we present an adaptive mode control method that can selectively excite the linearly polarized (LP) mode within the FMF. The method is based on using optical pulses reflected by a fiber Bragg grating (FBG) for wavefront optimization. Two potential applications are discussed. First, we theoretically demonstrate the feasibility of large scale multiplexing of absorption based fiber optical sensors. Second, we discuss the possibility of using mode dependent loss to reconstruct the spatial distributions of absorptive chemicals diffused within a FMF.

  20. Volume accumulator design analysis computer codes

    NASA Technical Reports Server (NTRS)

    Whitaker, W. D.; Shimazaki, T. T.

    1973-01-01

    The computer codes, VANEP and VANES, were written and used to aid in the design and performance calculation of the volume accumulator units (VAU) for the 5-kwe reactor thermoelectric system. VANEP computes the VAU design which meets the primary coolant loop VAU volume and pressure performance requirements. VANES computes the performance of the VAU design, determined from the VANEP code, at the conditions of the secondary coolant loop. The codes can also compute the performance characteristics of the VAU's under conditions of possible modes of failure which still permit continued system operation.

  1. Solids Accumulation Scouting Studies

    SciTech Connect

    Duignan, M. R.; Steeper, T. J.; Steimke, J. L.

    2012-09-26

    The objective of Solids Accumulation activities was to perform scaled testing to understand the behavior of remaining solids in a Double Shell Tank (DST), specifically AW-105, at Hanford during multiple fill, mix, and transfer operations. It is important to know if fissionable materials can concentrate when waste is transferred from staging tanks prior to feeding waste treatment plants. Specifically, there is a concern that large, dense particles containing plutonium could accumulate in poorly mixed regions of a blend tank heel for tanks that employ mixing jet pumps. At the request of the DOE Hanford Tank Operations Contractor, Washington River Protection Solutions, the Engineering Development Laboratory of the Savannah River National Laboratory performed a scouting study in a 1/22-scale model of a waste staging tank to investigate this concern and to develop measurement techniques that could be applied in a more extensive study at a larger scale. Simulated waste tank solids: Gibbsite, Zirconia, Sand, and Stainless Steel, with stainless steel particles representing the heavier particles, e.g., plutonium, and supernatant were charged to the test tank and rotating liquid jets were used to mix most of the solids while the simulant was pumped out. Subsequently, the volume and shape of the mounds of residual solids and the spatial concentration profiles for the surrogate for heavier particles were measured. Several techniques were developed and equipment designed to accomplish the measurements needed and they included: 1. Magnetic particle separator to remove simulant stainless steel solids. A device was designed and built to capture these solids, which represent the heavier solids during a waste transfer from a staging tank. 2. Photographic equipment to determine the volume of the solids mounds. The mounds were photographed as they were exposed at different tank waste levels to develop a composite of topographical areas. 3. Laser rangefinders to determine the volume of

  2. Mode conversion in ITER

    NASA Astrophysics Data System (ADS)

    Jaeger, E. F.; Berry, L. A.; Myra, J. R.

    2006-10-01

    Fast magnetosonic waves in the ion cyclotron range of frequencies (ICRF) can convert to much shorter wavelength modes such as ion Bernstein waves (IBW) and ion cyclotron waves (ICW) [1]. These modes are potentially useful for plasma control through the generation of localized currents and sheared flows. As part of the SciDAC Center for Simulation of Wave-Plasma Interactions project, the AORSA global-wave solver [2] has been ported to the new, dual-core Cray XT-3 (Jaguar) at ORNL where it demonstrates excellent scaling with the number of processors. Preliminary calculations using 4096 processors have allowed the first full-wave simulations of mode conversion in ITER. Mode conversion from the fast wave to the ICW is observed in mixtures of deuterium, tritium and helium3 at 53 MHz. The resulting flow velocity and electric field shear will be calculated. [1] F.W. Perkins, Nucl. Fusion 17, 1197 (1977). [2] E.F. Jaeger, L.A. Berry, J.R. Myra, et al., Phys. Rev. Lett. 90, 195001-1 (2003).

  3. Vibrational modes of nanolines

    NASA Astrophysics Data System (ADS)

    Heyliger, Paul R.; Flannery, Colm M.; Johnson, Ward L.

    2008-04-01

    Brillouin-light-scattering spectra previously have been shown to provide information on acoustic modes of polymeric lines fabricated by nanoimprint lithography. Finite-element methods for modeling such modes are presented here. These methods provide a theoretical framework for determining elastic constants and dimensions of nanolines from measured spectra in the low gigahertz range. To make the calculations feasible for future incorporation in inversion algorithms, two approximations of the boundary conditions are employed in the calculations: the rigidity of the nanoline/substrate interface and sinusoidal variation of displacements along the nanoline length. The accuracy of these approximations is evaluated as a function of wavenumber and frequency. The great advantage of finite-element methods over other methods previously employed for nanolines is the ability to model any cross-sectional geometry. Dispersion curves and displacement patterns are calculated for modes of polymethyl methacrylate nanolines with cross-sectional dimensions of 65 nm × 140 nm and rectangular or semicircular tops. The vibrational displacements and dispersion curves are qualitatively similar for the two geometries and include a series of flexural, Rayleigh-like, and Sezawa-like modes. This paper is a contribution of the National Institute of Standards and Technology and is not subject to copyright in the United States.

  4. Mixed-Mode-Bending Delamination Apparatus

    NASA Technical Reports Server (NTRS)

    Crews, John H., Jr.; Reeder, James R.

    1991-01-01

    Mixed-mode-bending delamination apparatus generates two types of delamination stress simultaneously in specimen from single externally applied point load. In technique, indivial mode I and mode II contributions to delamination in specimen analyzed by use of simple beam-theory equations, eliminating need for time-consuming, difficult numerical analysis. Allows wider range of mode I/mode II ratios than possible with many other methods. Mixed-mode delamination testing of interest in all fields utilizing composite materials, used mostly in aerospace field, but also used in automobiles, lightweight armored military vehicles, boats, and sporting equipment. Useful in general lumber, plywood, and adhesive industries, as well.

  5. Heavy Particle Modes and I-mode Plasmas

    NASA Astrophysics Data System (ADS)

    Victora, M.; Coppi, B.; Zhou, T.

    2012-10-01

    The excitation of a heavy particle mode [1,2] at the plasma edge is considered as the signature of the I-Regime [3]. The mode phase velocity, predicted in the electron diamagnetic velocity direction, was confirmed by the experiments [4]. The outward impurity transport produced by this mode is consistent with the observation that impurities accumulate at the edge in the I-Regime, a feature not present in the EDA or Elmy H-Regime. The plasma spontaneous rotation in the ion diamagnetic velocity direction is also consistent with the mode phase velocity direction, according to the Accretion Theory [5] of this phenomenon. In accordance with our theory, the I-Regime exhibits a temperature pedestal at the edge but no density pedestal as the mode excitation involves large values of dTi/dni. A correlation of the values of the observed poloidal magnetic field fluctuations with those of the derived density fluctuations is provided by the same theory.[4pt] [1] B. Coppi et al., Phys. Rev. Lett. 17, 377 (1966).[0pt] [2] B. Coppi and T. Zhou, Phys. Lett. A 375, 2916 (2011); PoP 19, 012302 (2012).[0pt] [3] A. Hubbard et al., PoP 18, 056115 (2011).[0pt] [4] I. Cziegler (2010).[0pt] [5] B. Coppi, Nucl. Fusion 42, 1 (2002).

  6. Noise Reduction by Signal Accumulation

    ERIC Educational Resources Information Center

    Kraftmakher, Yaakov

    2006-01-01

    The aim of this paper is to show how the noise reduction by signal accumulation can be accomplished with a data acquisition system. This topic can be used for student projects. In many cases, the noise reduction is an unavoidable part of experimentation. Several techniques are known for this purpose, and among them the signal accumulation is the…

  7. Accumulated damage process of thermal sprayed coating under rolling contact by acoustic emission technique

    NASA Astrophysics Data System (ADS)

    Xu, Jia; Zhou, Zhen-yu; Piao, Zhong-yu

    2016-09-01

    The accumulated damage process of rolling contact fatigue (RCF) of plasma-sprayed coatings was investigated. The influences of surface roughness, loading condition, and stress cycle frequency on the accumulated damage status of the coatings were discussed. A ball-ondisc machine was employed to conduct RCF experiments. Acoustic emission (AE) technique was introduced to monitor the RCF process of the coatings. AE signal characteristics were investigated to reveal the accumulated damage process. Result showed that the polished coating would resist the asperity contact and remit accumulated damage. The RCF lifetime would then extend. Heavy load would aggravate the accumulated damage status and induce surface fracture. Wear became the main failure mode that reduced the RCF lifetime. Frequent stress cycle would aggravate the accumulated damage status and induce interface fracture. Fatigue then became the main failure mode that also reduced the RCF lifetime.

  8. The Long-Range Impact of Television.

    ERIC Educational Resources Information Center

    Comstock, George

    Long range effects may be of three varieties: those which are observable in the immediate period subsequent to exposure but are long range because of their continuing repetitive accumulation with each exposure; those which represent the cumulative or delayed impact on individuals of exposure to television; or those which represent the immediate…

  9. Detection of Solar Oscillations (g-modes)

    NASA Astrophysics Data System (ADS)

    Homayouni, Y.; Ajabshirizadeh, A.

    2011-07-01

    Solar gravity modes are the best probes to study solar interior and specifically the dynamics of solar core. Here we present an analytical solution to solar gravity modes using relativistic space curvature inside 0.4 fractional radius with the assumption of mass accumulation inside the solar core. Considering the radial effect of gravitation, in order to calculate the spherical harmonics we have set the value of l to zero. Furthermore, a modified geometry for the interior regions of the Sun is presented. Consequently, a relation of g-mode frequency with fractional radius is calculated.

  10. Study of Density Fluctuations and Particle Transport at the Edge of I-Mode Plasmas

    NASA Astrophysics Data System (ADS)

    Dominguez, Arturo

    The wide range of plasma parameters available on Alcator C-Mod has led to the accessibility of many regimes of operation. Since its commissioning, C-Mod has accessed the Linear ohmic confinement, Saturated ohmic confinement, L-Mode and ELM-free, ELMy and Enhanced Dalpha H-Mode regimes. Recently, another novel regime, the I-Mode, has been identified. I-modes feature the presence of steep H-Mode-like electron and ion temperature gradients at the edge of the plasma with L-Mode-like density profiles. The I-Mode, in contrast to the H-mode, shows very weak degradation of energy confinement with increased input power, and routinely reaches H 98 > 1 while operating at low edge collisionalities ( n*ped ˜0.1), making it a good candidate for reactor relevant tokamaks. Also relevant for reactors, this regime can be sustained in steady state for more than ˜15 energy confinement times without the need for ELMs to regulate particle and impurity confinement. Changes in edge density, temperature and magnetic field fluctuations accompany the L-mode to I-mode transition, with reduction of fluctuations in the 50--150kHz range as well as the appearance of a Weakly Coherent Mode (WCM) in the 200-300kHz range, analogous to the Quasi-Coherent Mode (QCM) characteristic of the Enhanced D alpha H-mode. Previous work has established a connection between the midrange fluctuation suppression and reduction in the effective thermal diffusivity, chi eff, in the pedestal region. The mechanism in I-mode for maintaining sufficient particle transport to avoid impurity accumulation and instabilities has been unclear. The O-mode reflectometry system has been extensively used for the characterization and detection of the I-mode and the WCM, in part, enhanced by upgrades to the system which enabled the broadband detection of density fluctuations at an array of cutoff locations at the edge of the plasma. Using a novel model, the autopower signals of reflectometry channels detecting the density

  11. Gypsum accumulation on carbonate stone

    USGS Publications Warehouse

    McGee, E.S.; Mossotti, V.G.

    1992-01-01

    The accumulation of gypsum on carbonate stone has been investigated through exposure of fresh samples of limestone and marble at monitored sites, through examination of alteration crusts from old buildings and through laboratory experiments. Several factors contribute to gypsum accumulation on carbonate stone. Marble or limestone that is sheltered from direct washing by rain in an urban environment with elevated pollution levels is likely to accumulate a gypsum crust. Crust development may be enhanced if the stone is porous or has an irregular surface area. Gypsum crusts are a surficial alteration feature; gypsum crystals form at the pore opening-air interface, where evaporation is greatest.

  12. Strain accumulation in quasicrystalline solids

    NASA Technical Reports Server (NTRS)

    Nori, Franco; Ronchetti, Marco; Elser, Veit

    1988-01-01

    The relaxation of two-dimensional quasicrystalline elastic networks when their constituent bonds are perturbed homogeneously is studied. Whereas ideal, quasi-periodic networks are stable against such perturbations, significant accumulations of strain in a class of disordered networks generated by a growth process are found. The grown networks are characterized by root mean square phason fluctuations which grow linearly with system size. The strain accumulation observed in these networks also grows linearly with system size. Finally, dependence of strain accumulation on cooling rate is found.

  13. Dynamics of alternative modes of RNA replication for positive-sense RNA viruses.

    PubMed

    Sardanyés, Josep; Martínez, Fernando; Daròs, José-Antonio; Elena, Santiago F

    2012-04-07

    We propose and study nonlinear mathematical models describing the intracellular time dynamics of viral RNA accumulation for positive-sense single-stranded RNA viruses. Our models consider different replication modes ranging between two extremes represented by the geometric replication (GR) and the linear stamping machine replication (SMR). We first analyse a model that quantitatively reproduced experimental data for the accumulation dynamics of both polarities of turnip mosaic potyvirus RNAs. We identify a non-degenerate transcritical bifurcation governing the extinction of both strands depending on three key parameters: the mode of replication (α), the replication rate (r) and the degradation rate (δ) of viral strands. Our results indicate that the bifurcation associated with α generically takes place when the replication mode is closer to the SMR, thus suggesting that GR may provide viral strands with an increased robustness against degradation. This transcritical bifurcation, which is responsible for the switching from an active to an absorbing regime, suggests a smooth (i.e. second-order), absorbing-state phase transition. Finally, we also analyse a simplified model that only incorporates asymmetry in replication tied to differential replication modes.

  14. Wide-range radiation dose monitor

    DOEpatents

    Kopp, Manfred K.

    1986-01-01

    A radiation dose-rate monitor is provided which operates in a conventional linear mode for radiation in the 0 to 0.5 R/h range and utilizes a nonlinear mode of operation for sensing radiation from 0.5 R/h to over 500 R/h. The nonlinear mode is achieved by a feedback circuit which adjusts the high voltage bias of the proportional counter, and hence its gas gain, in accordance with the amount of radiation being monitored. This allows compression of readout onto a single scale over the range of 0 to greater than 500 R/h without scale switching operations.

  15. Wide-range radiation dose monitor

    DOEpatents

    Kopp, M.K.

    1984-09-20

    A radiation dose-rate monitor is provided which operates in a conventional linear mode for radiation in the 0 to 0.5 R/h range and utilizes a nonlinear mode of operation for sensing radiation from 0.5 R/h to over 500 R/h. The nonlinear mode is achieved by a feedback circuit which adjusts the high voltage bias of the proportional counter, and hence its gas gain, in accordance with the amount of radiation being monitored. This allows compression of readout onto a single scale over the range of 0 to greater than 500 R/h without scale switching operations.

  16. Whispering Gallery Mode Thermometry

    PubMed Central

    Corbellini, Simone; Ramella, Chiara; Yu, Lili; Pirola, Marco; Fernicola, Vito

    2016-01-01

    This paper presents a state-of-the-art whispering gallery mode (WGM) thermometer system, which could replace platinum resistance thermometers currently used in many industrial applications, thus overcoming some of their well-known limitations and their potential for providing lower measurement uncertainty. The temperature-sensing element is a sapphire-crystal-based whispering gallery mode resonator with the main resonant modes between 10 GHz and 20 GHz. In particular, it was found that the WGM around 13.6 GHz maximizes measurement performance, affording sub-millikelvin resolution and temperature stability of better than 1 mK at 0 °C. The thermometer system was made portable and low-cost by developing an ad hoc interrogation system (hardware and software) able to achieve an accuracy in the order of a few parts in 109 in the determination of resonance frequencies. Herein we report the experimental assessment of the measurement stability, repeatability and resolution, and the calibration of the thermometer in the temperature range from −74 °C to 85 °C. The combined standard uncertainty for a single temperature calibration point is found to be within 5 mK (i.e., comparable with state-of-the-art for industrial thermometry), and is mainly due to the employed calibration setup. The uncertainty contribution of the WGM thermometer alone is within a millikelvin. PMID:27801868

  17. Manganese As a Metal Accumulator

    EPA Science Inventory

    Manganese deposits in water distribution systems accumulate metals, radionuclides and oxyanions by a combination of surface complexation, adsorption and solid substitution, as well as a combination of oxidation followed by manganese reduction and sorption of the oxidized constitu...

  18. Maximum thrust mode evaluation

    NASA Technical Reports Server (NTRS)

    Orme, John S.; Nobbs, Steven G.

    1995-01-01

    Measured reductions in acceleration times which resulted from the application of the F-15 performance seeking control (PSC) maximum thrust mode during the dual-engine test phase is presented as a function of power setting and flight condition. Data were collected at altitudes of 30,000 and 45,000 feet at military and maximum afterburning power settings. The time savings for the supersonic acceleration is less than at subsonic Mach numbers because of the increased modeling and control complexity. In addition, the propulsion system was designed to be optimized at the mid supersonic Mach number range. Recall that even though the engine is at maximum afterburner, PSC does not trim the afterburner for the maximum thrust mode. Subsonically at military power, time to accelerate from Mach 0.6 to 0.95 was cut by between 6 and 8 percent with a single engine application of PSC, and over 14 percent when both engines were optimized. At maximum afterburner, the level of thrust increases were similar in magnitude to the military power results, but because of higher thrust levels at maximum afterburner and higher aircraft drag at supersonic Mach numbers the percentage thrust increase and time to accelerate was less than for the supersonic accelerations. Savings in time to accelerate supersonically at maximum afterburner ranged from 4 to 7 percent. In general, the maximum thrust mode has performed well, demonstrating significant thrust increases at military and maximum afterburner power. Increases of up to 15 percent at typical combat-type flight conditions were identified. Thrust increases of this magnitude could be useful in a combat situation.

  19. Constant-Differential-Pressure Two-Fluid Accumulator

    NASA Technical Reports Server (NTRS)

    Piecuch, Benjamin; Dalton, Luke T.

    2010-01-01

    A two-fluid accumulator has been designed, built, and demonstrated to provide an acceptably close approximation to constant differential static pressure between two fluids over the full ranges of (1) accumulator stroke, (2) rates of flow of the fluids, and (3) common static pressure applied to the fluids. Prior differential- pressure two-fluid accumulators are generally not capable of maintaining acceptably close approximations to constant differential pressures. The inadequacies of a typical prior differential-pressure two-fluid accumulator can be summarized as follows: The static differential pressure is governed by the intrinsic spring rate (essentially, the stiffness) of an accumulator tank. The spring rate can be tailored through selection of the tank-wall thickness, selection of the number and/or shape of accumulator convolutions, and/or selection of accumulator material(s). Reliance on the intrinsic spring rate of the tank results in three severe limitations: (1) The spring rate and the expulsion efficiency tend to be inversely proportional to each other: that is to say, as the stiffness (and thus the differential pressure) is increased, the range of motion of the accumulator is reduced. (2) As the applied common static pressure increases, the differential pressure tends to decrease. An additional disadvantage, which may or may not be considered limiting, depending on the specific application, is that an increase in stiffness entails an increase in weight. (3) The additional weight required by a low expulsion efficiency accumulator eliminates the advantage given to such gas storage systems. The high expulsion efficiency provided by this two-fluid accumulator allows for a lightweight, tightly packaged system, which can be used in conjunction with a fuel cell-based system.

  20. Analysis of sucrose accumulation in the sugar cane culm on the basis of in vitro kinetic data.

    PubMed Central

    Rohwer, J M; Botha, F C

    2001-01-01

    Sucrose accumulation in developing sugar cane (Saccharum officinarum) is accompanied by a continuous synthesis and cleavage of sucrose in the storage tissues. Despite numerous studies, the factors affecting sucrose accumulation are still poorly understood, and no consistent pattern has emerged which pinpoints certain enzyme activities as important controlling steps. Here, we develop an approach based on pathway analysis and kinetic modelling to assess the biochemical control of sucrose accumulation and futile cycling in sugar cane. By using the concept of elementary flux modes, all possible routes of futile cycling of sucrose were enumerated in the metabolic system. The available kinetic data for the pathway enzymes were then collected and assembled in a kinetic model of sucrose accumulation in sugar cane culm tissue. Although no data were fitted, the model agreed well with independent experimental results: in no case was the difference between calculated and measured fluxes and concentrations greater than 2-fold. The model thus validated was then used to assess different enhancement strategies for increasing sucrose accumulation. First, the control coefficient of each enzyme in the system on futile cycling of sucrose was calculated. Secondly, the activities of those enzymes with the numerically largest control coefficients were varied over a 5-fold range to determine the effect on the degree of futile cycling, the conversion efficiency from hexoses into sucrose, and the net sucrose accumulation rate. In view of the modelling results, overexpression of the fructose or glucose transporter or the vacuolar sucrose import protein, as well as reduction of cytosolic neutral invertase levels, appear to be the most promising targets for genetic manipulation. This offers a more directed improvement strategy than cumbersome gene-by-gene manipulation. The kinetic model can be viewed and interrogated on the World Wide Web at http://jjj.biochem.sun.ac.za. PMID:11513743

  1. Atmospheric mercury accumulation and washoff processes on impervious urban surfaces

    USGS Publications Warehouse

    Eckley, C.S.; Branfireun, B.; Diamond, M.; Van Metre, P.C.; Heitmuller, F.

    2008-01-01

    The deposition and transport of mercury (Hg) has been studied extensively in rural environments but is less understood in urbanized catchments, where elevated atmospheric Hg concentrations and impervious surfaces may efficiently deliver Hg to waterways in stormwater runoff. We determined the rate at which atmospheric Hg accumulates on windows, identified the importance of washoff in removing accumulated Hg, and measured atmospheric Hg concentrations to help understand the relationship between deposition and surface accumulation. The main study location was Toronto, Ontario. Similar samples were also collected from Austin, Texas for comparison of Hg accumulation between cities. Windows provided a good sampling surface because they are ubiquitous in urban environments and are easy to clean/blank allowing the assessment of contemporary Hg accumulation. Hg Accumulation rates were spatially variable ranging from 0.82 to 2.7 ng m-2 d-1 in Toronto and showed similar variability in Austin. The highest accumulation rate in Toronto was at the city center and was 5?? higher than the rural comparison site (0.58 ng m-2 d-1). The atmospheric total gaseous mercury (TGM) concentrations were less than 2?? higher between the rural and urban locations (1.7 ?? 0.3 and 2.7 ?? 1.1 ng m-3, respectively). The atmospheric particulate bound fraction (HgP), however, was more than 3?? higher between the rural and urban sites, which may have contributed to the higher urban Hg accumulation rates. Windows exposed to precipitation had 73 ?? 9% lower accumulation rates than windows sheltered from precipitation. Runoff collected from simulated rain events confirmed that most Hg accumulated on windows was easily removed and that most of the Hg in washoff was HgP. Our results indicate that the Hg flux from urban catchments will respond rapidly to changes in atmospheric concentrations due to the mobilization of the majority of the surface accumulated Hg during precipitation events. ?? 2008 Elsevier

  2. Determining Greenland Ice Sheet Accumulation Rates from Radar Remote Sensing

    NASA Technical Reports Server (NTRS)

    Jezek, Kenneth C.

    2002-01-01

    An important component of NASA's Program for Arctic Regional Climate Assessment (PARCA) is a mass balance investigation of the Greenland Ice Sheet. The mass balance is calculated by taking the difference between the areally Integrated snow accumulation and the net ice discharge of the ice sheet. Uncertainties in this calculation Include the snow accumulation rate, which has traditionally been determined by interpolating data from ice core samples taken from isolated spots across the ice sheet. The sparse data associated with ice cores juxtaposed against the high spatial and temporal resolution provided by remote sensing , has motivated scientists to investigate relationships between accumulation rate and microwave observations as an option for obtaining spatially contiguous estimates. The objective of this PARCA continuation proposal was to complete an estimate of surface accumulation rate on the Greenland Ice Sheet derived from C-band radar backscatter data compiled in the ERS-1 SAR mosaic of data acquired during, September-November, 1992. An empirical equation, based on elevation and latitude, is used to determine the mean annual temperature. We examine the influence of accumulation rate, and mean annual temperature on C-band radar backscatter using a forward model, which incorporates snow metamorphosis and radar backscatter components. Our model is run over a range of accumulation and temperature conditions. Based on the model results, we generate a look-up table, which uniquely maps the measured radar backscatter, and mean annual temperature to accumulation rate. Our results compare favorably with in situ accumulation rate measurements falling within our study area.

  3. Anthocyanins facilitate tungsten accumulation in Brassica

    SciTech Connect

    Hale, K.L.

    2002-11-01

    Accumulation of molybdenum in Brassica was recently found to be correlated with anthocyanin content, involving the formation of a blue complex. Here the role of anthocyanins in tungsten sequestration was investigated using three species of Brassica: B. rapa (cv. Fast plants), B. juncea (Indian mustard) and B. oleracea (red cabbage). Seedlings of B. rapa and B. juncea turned blue when supplied with colourless tungstate. The blue compound co-localized with anthocyanins in the peripheral cell layers, and the degree of blueness was correlated with anthocyanin content. The direct involvement of anthocyanins in the blue coloration was evident when purified anthocyanins showed a colour change from pink to blue in vitro upon addition of tungstate, over a wide pH range. Anthocyanin production was upregulated 3-fold by W in B. juncea, possibly reflecting a function for anthocyanins in W tolerance or sequestration. The presence of anthocyanins facilitated W accumulation in B. rapa: anthocyanin-containing seedlings accumulated 3-fold more W than an anthocyaninless mutant. There was no correlation between anthocyanin content and W tolerance under these conditions. The nature of the interaction between anthocyanins and tungstate was investigated. X-ray absorption spectroscopy showed no change in the local chemical environment of Wupon uptake of tungstate by the plant; HPLC analysis of purified anthocyanin with or without tungstate showed no peak shift after metal treatment.

  4. Maximum likelihood decoding analysis of Accumulate-Repeat-Accumulate Codes

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    Repeat-Accumulate (RA) codes are the simplest turbo-like codes that achieve good performance. However, they cannot compete with Turbo codes or low-density parity check codes (LDPC) as far as performance is concerned. The Accumulate Repeat Accumulate (ARA) codes, as a subclass of LDPC codes, are obtained by adding a pre-coder in front of RA codes with puncturing where an accumulator is chosen as a precoder. These codes not only are very simple, but also achieve excellent performance with iterative decoding. In this paper, the performance of these codes with (ML) decoding are analyzed and compared to random codes by very tight bounds. The weight distribution of some simple ARA codes is obtained, and through existing tightest bounds we have shown the ML SNR threshold of ARA codes approaches very closely to the performance of random codes. We have shown that the use of precoder improves the SNR threshold but interleaving gain remains unchanged with respect to RA code with puncturing.

  5. Broadband radiation modes: estimation and active control.

    PubMed

    Berkhoff, Arthur P

    2002-03-01

    In this paper we give a formulation of the most efficiently radiating vibration patterns of a vibrating body, the radiation modes, in the time domain. The radiation modes can be used to arrive at efficient weighting schemes for an array of sensors in order to reduce the controller dimensionality. Because these particular radiation modes are optimum in a broadband sense, they are termed broadband radiation modes. Methods are given to obtain these modes from measured data. The broadband radiation modes are used for the design of an actuator array in a feedback control system to reduce the sound power radiated from a plate. Three methods for the design of the actuator are compared, taking into account the reduction of radiated sound power in the controlled frequency range, but also the possible increase of radiated sound power in the uncontrolled frequency range.

  6. Laser system of extended range

    NASA Technical Reports Server (NTRS)

    Lehr, C. G.

    1972-01-01

    A pulsed laser system was developed for range measurements from the earth to retroreflecting satellites at distances up to that of the moon. The system has a transportable transmitter unit that can be moved from one location to another. This unit consists of a 0.2 m coude refractor and a high radiance, neodymium-glass, frequency doubled laser that operates in a single transverse mode. It can be used for lunar or distant satellite ranging at any observatory that has a telescope with an aperture diameter of about 1.5 m for the detection of the laser return pulses. This telescope is utilized in the same manner customarily employed for the observation of celestial objects. A special photometric package and the associated electronics are provided for laser ranging.

  7. Multi-Mode Broadband Patch Antenna

    NASA Technical Reports Server (NTRS)

    Romanofsky, Robert R. (Inventor)

    2001-01-01

    A multi-mode broad band patch antenna is provided that allows for the same aperture to be used at independent frequencies such as reception at 19 GHz and transmission at 29 GHz. Furthermore, the multi-mode broadband patch antenna provides a ferroelectric film that allows for tuning capability of the multi-mode broadband patch antenna over a relatively large tuning range. The alternative use of a semiconductor substrate permits reduced control voltages since the semiconductor functions as a counter electrode.

  8. List mode multichannel analyzer

    DOEpatents

    Archer, Daniel E.; Luke, S. John; Mauger, G. Joseph; Riot, Vincent J.; Knapp, David A.

    2007-08-07

    A digital list mode multichannel analyzer (MCA) built around a programmable FPGA device for onboard data analysis and on-the-fly modification of system detection/operating parameters, and capable of collecting and processing data in very small time bins (<1 millisecond) when used in histogramming mode, or in list mode as a list mode MCA.

  9. A la Mode II.

    ERIC Educational Resources Information Center

    Stowe, Richard A.

    This paper describes two modes of educational decision-making: Mode I, in which the instructor makes such decisions as what to teach, to whom, when, in what order, at what pace, and at what complexity level; and Mode II, in which the learner makes the decisions. While Mode I comprises most of what is regarded as formal education, the learner in…

  10. Ultrasonic ranging for the oculometer

    NASA Technical Reports Server (NTRS)

    Guy, W. J.

    1981-01-01

    Ultrasonic tracking techniques are investigated for an oculometer. Two methods are reported in detail. The first is based on measurements of time from the start of a transmit burst to a received echo. Knowing the sound velocity, distance can be calculated. In the second method, a continuous signal is transmitted. Target movement causes phase shifting of the echo. By accumulating these phase shifts, tracking from a set point can be achieved. Both systems have problems with contoured targets, but work well on flat plates and the back of a human head. Also briefly reported is an evaluation of an ultrasonic ranging system. Interface circuits make this system compatible with the echo time design. While the system is consistently accurate, it has a beam too narrow for oculometer use. Finally, comments are provided on a tracking system using the Doppler frequency shift to give range data.

  11. Ion Trapping in the Accumulator

    SciTech Connect

    Marriner, J.

    1985-02-18

    The beam space charge (- for {bar p}'s) will attract positive ions. In the absence of additional fields (clearing electrodes, e.g.) these ions will be trapped in the beam potential well. The depth of this potential well has been calculated for some geometries relevant for the accumulator.

  12. Plasmonic wave propagation in silver nanowires: guiding modes or not?

    PubMed

    Li, Qiang; Qiu, Min

    2013-04-08

    Propagation modes and single-guiding-mode conditions of one-dimensional silver nanowires based surface plasmon polariton (SPP) waveguides versus the operating wavelength (500-2000 nm) are investigated. For silver nanowires immersed in a SiO(2) matrix, both short-range SPP (SRSPP)-like modes and long-range SPP (LRSPP)-like modes can be guided. However, only the LRSPP-like modes have cutoff radii. For silver nanowires on a SiO(2) substrate, the LRSPP-like modes cannot be supported due to asymmetry. While for the SRSPP-like guiding mode, it has a cutoff radius for wavelength longer than 615 nm. For wavelength shorter than 615 nm, there is no cutoff radius for the guiding modes due to the appearance of the interface modes and thus the single-guiding-mode operation is always satisfied.

  13. Trace element accumulation in lotic dragonfly nymphs: Genus matters

    PubMed Central

    Fletcher, Dean E.; Lindell, Angela H.; Stillings, Garrett K.; Blas, Susan A.; McArthur, J. Vaun

    2017-01-01

    Constituents of coal combustion waste (CCW) expose aquatic organisms to complex mixtures of potentially toxic metals and metalloids. Multi-element trace element analyses were used to distinguish patterns of accumulation among 8 genera of dragonfly nymphs collected from two sites on a CCW contaminated coastal plain stream. Dragonfly nymphs are exceptional for comparing trace element accumulation in syntopic macroinvertebrates that are all predators within the same order (Odonata) and suborder (Anisoptera), but differ vastly in habitat use and body form. Sixteen trace element (Be, V, Cr, Ni, Cu, Zn, As, Se, Sr, Cd, Sb, Cs, Ba, Hg, Tl, and Pb) were analyzed and trophic position and basal carbon sources assessed with stable isotope analyses (C and N). Trophic positions varied within relatively narrow ranges. Size did not appear to influence trophic position. Trophic position rarely influenced trace element accumulation within genera and did not consistently correlate with accumulation among genera. Patterns between δ13C and trace element accumulation were generally driven by differences between sites. An increase in trace element accumulation was associated with a divergence of carbon sources between sites in two genera. Higher trace element concentrations tended to accumulate in nymphs from the upstream site, closer to contaminant sources. Influences of factors such as body form and habitat use appeared more influential on trace element accumulation than phylogeny for several elements (Ni, Ba, Sr, V, Be, Cd, and Cr) as higher concentrations accumulated in sprawler and the climber-sprawler genera, irrespective of family. In contrast, As and Se accumulated variably higher in burrowers, but accumulation in sprawlers differed between sites. Greater variation between genera than within genera suggests genus as an acceptable unit of comparison in dragonfly nymphs. Overall, taxonomic differences in trace element accumulation can be substantial, often exceeding variation

  14. Trace element accumulation in lotic dragonfly nymphs: Genus matters.

    PubMed

    Fletcher, Dean E; Lindell, Angela H; Stillings, Garrett K; Blas, Susan A; McArthur, J Vaun

    2017-01-01

    Constituents of coal combustion waste (CCW) expose aquatic organisms to complex mixtures of potentially toxic metals and metalloids. Multi-element trace element analyses were used to distinguish patterns of accumulation among 8 genera of dragonfly nymphs collected from two sites on a CCW contaminated coastal plain stream. Dragonfly nymphs are exceptional for comparing trace element accumulation in syntopic macroinvertebrates that are all predators within the same order (Odonata) and suborder (Anisoptera), but differ vastly in habitat use and body form. Sixteen trace element (Be, V, Cr, Ni, Cu, Zn, As, Se, Sr, Cd, Sb, Cs, Ba, Hg, Tl, and Pb) were analyzed and trophic position and basal carbon sources assessed with stable isotope analyses (C and N). Trophic positions varied within relatively narrow ranges. Size did not appear to influence trophic position. Trophic position rarely influenced trace element accumulation within genera and did not consistently correlate with accumulation among genera. Patterns between δ13C and trace element accumulation were generally driven by differences between sites. An increase in trace element accumulation was associated with a divergence of carbon sources between sites in two genera. Higher trace element concentrations tended to accumulate in nymphs from the upstream site, closer to contaminant sources. Influences of factors such as body form and habitat use appeared more influential on trace element accumulation than phylogeny for several elements (Ni, Ba, Sr, V, Be, Cd, and Cr) as higher concentrations accumulated in sprawler and the climber-sprawler genera, irrespective of family. In contrast, As and Se accumulated variably higher in burrowers, but accumulation in sprawlers differed between sites. Greater variation between genera than within genera suggests genus as an acceptable unit of comparison in dragonfly nymphs. Overall, taxonomic differences in trace element accumulation can be substantial, often exceeding variation

  15. Minimum fuel mode evaluation

    NASA Technical Reports Server (NTRS)

    Orme, John S.; Nobbs, Steven G.

    1995-01-01

    The minimum fuel mode of the NASA F-15 research aircraft is designed to minimize fuel flow while maintaining constant net propulsive force (FNP), effectively reducing thrust specific fuel consumption (TSFC), during cruise flight conditions. The test maneuvers were at stabilized flight conditions. The aircraft test engine was allowed to stabilize at the cruise conditions before data collection initiated; data were then recorded with performance seeking control (PSC) not-engaged, then data were recorded with the PSC system engaged. The maneuvers were flown back-to-back to allow for direct comparisons by minimizing the effects of variations in the test day conditions. The minimum fuel mode was evaluated at subsonic and supersonic Mach numbers and focused on three altitudes: 15,000; 30,000; and 45,000 feet. Flight data were collected for part, military, partial, and maximum afterburning power conditions. The TSFC savings at supersonic Mach numbers, ranging from approximately 4% to nearly 10%, are in general much larger than at subsonic Mach numbers because of PSC trims to the afterburner.

  16. Mode conversion heating experiments on Tore Supra

    SciTech Connect

    Saoutic, B.; Becoulet, A.; Hutter, T.; Fraboulet, D.; Ram, A.K.; Bers, A.

    1996-02-01

    A new scenario for effeicient mode conversion heating, in the ion cyclotron range of frequency, is proposed. Experiments on Tore Supra demonstrate that this new scheme is quite efficient. A detailed analysis of thes mode conversion scenario is carried out, using a new complete 1-D model and the 3-D full wave code Alcyon. {copyright} {ital 1996 American Institute of Physics.}

  17. Mode conversion heating experiments on Tore Supra

    NASA Astrophysics Data System (ADS)

    Saoutic, B.; Bécoulet, A.; Hutter, T.; Fraboulet, D.; Ram, A. K.; Bers, A.

    1996-02-01

    A new scenario for effeicient mode conversion heating, in the ion cyclotron range of frequency, is proposed. Experiments on Tore Supra demonstrate that this new scheme is quite efficient. A detailed analysis of thes mode conversion scenario is carried out, using a new complete 1-D model and the 3-D full wave code Alcyon.

  18. Long Range Acoustic Communication in Deep Water

    DTIC Science & Technology

    2014-09-30

    Acoustic communication at long range in the ocean is challenging due to the substantial propagation loss, multipath delay spread , and channel...20 Hz in the upward refracting Arctic acoustic channel. However, the seafloor topography in the region of the Chukchi Plateau is very uneven over...which the depth was 600 m and thus the seafloor affected every mode of the ACOUS signal except for mode 1 which was confined to the upper 200 m. In April

  19. Fast range estimation based on active range-gated imaging for coastal surveillance

    NASA Astrophysics Data System (ADS)

    Kong, Qingshan; Cao, Yinan; Wang, Xinwei; Tong, Youwan; Zhou, Yan; Liu, Yuliang

    2012-11-01

    Coastal surveillance is very important because it is useful for search and rescue, illegal immigration, or harbor security and so on. Furthermore, range estimation is critical for precisely detecting the target. Range-gated laser imaging sensor is suitable for high accuracy range especially in night and no moonlight. Generally, before detecting the target, it is necessary to change delay time till the target is captured. There are two operating mode for range-gated imaging sensor, one is passive imaging mode, and the other is gate viewing mode. Firstly, the sensor is passive mode, only capturing scenes by ICCD, once the object appears in the range of monitoring area, we can obtain the course range of the target according to the imaging geometry/projecting transform. Then, the sensor is gate viewing mode, applying micro second laser pulses and sensor gate width, we can get the range of targets by at least two continuous images with trapezoid-shaped range intensity profile. This technique enables super-resolution depth mapping with a reduction of imaging data processing. Based on the first step, we can calculate the rough value and quickly fix delay time which the target is detected. This technique has overcome the depth resolution limitation for 3D active imaging and enables super-resolution depth mapping with a reduction of imaging data processing. By the two steps, we can quickly obtain the distance between the object and sensor.

  20. Mode coupling in hybrid square-rectangular lasers for single mode operation

    NASA Astrophysics Data System (ADS)

    Ma, Xiu-Wen; Huang, Yong-Zhen; Yang, Yue-De; Xiao, Jin-Long; Weng, Hai-Zhong; Xiao, Zhi-Xiong

    2016-08-01

    Mode coupling between a square microcavity and a Fabry-Pérot (FP) cavity is proposed and demonstrated for realizing single mode lasers. The modulations of the mode Q factor as simulation results are observed and single mode operation is obtained with a side mode suppression ratio of 46 dB and a single mode fiber coupling loss of 3.2 dB for an AlGaInAs/InP hybrid laser as a 300-μm-length and 1.5-μm-wide FP cavity connected to a vertex of a 10-μm-side square microcavity. Furthermore, tunable single mode operation is demonstrated with a continuous wavelength tuning range over 10 nm. The simple hybrid structure may shed light on practical applications of whispering-gallery mode microcavities in large-scale photonic integrated circuits and optical communication and interconnection.

  1. Patterns of sediment accumulation in the tidal marshes of Maine

    USGS Publications Warehouse

    Wood, M.E.; Kelley, J.T.; Belknap, D.F.

    1989-01-01

    One year's measurements of surficial sedimentation rates (1986-1987) for 26 Maine marsh sites were made over marker horizons of brick dust. Observed sediment accumulation rates, from 0 to 13 mm yr-1, were compared with marsh morphology, local relative sea-level rise rate, mean tidal range, and ice rafting activity. Marshes with four different morphologies (back-barrier, fluvial, bluff-toe, and transitional) showed distinctly different sediment accumulation rates. In general, back-barrier marshes had the highest accumulation rates and blufftoe marshes had the lowest rates, with intermediate values for transitional and fluvial marshes. No causal relationship between modern marsh sediment accumulation rate and relative sea-level rise rate (from tide gauge records) was observed. Marsh accretionary balance (sediment accumulation rate minus relative sea-level rise rate) did not correlate with mean tidal range for this meso- to macro-tidal area. Estimates of ice-rafted debris on marsh sites ranged from 0% to >100% of measured surficial sedimentation rates, indicating that ice transport of sediment may make a significant contribution to surficial sedimentation on Maine salt marshes. ?? 1989 Estuarine Research Federation.

  2. Raman spectroscopy of selected tsumcorite Pb(Zn,Fe3+)2(AsO4)2(OH,H2O) minerals--implications for arsenate accumulation.

    PubMed

    Frost, Ray L; Xi, Yunfei

    2012-02-01

    The presence of arsenic in the environment is a hazard. The accumulation of arsenate by a range of cations in the formation of minerals provides a mechanism for the accumulation of arsenate. The formation of the tsumcorite minerals is an example of a series of minerals which accumulate arsenate. There are about twelve examples in this mineral group. Raman spectroscopy offers a method for the analysis of these minerals. The structure of selected tsumcorite minerals with arsenate and sulphate anions were analysed by Raman spectroscopy. Isomorphic substitution of sulphate for arsenate is observed for gartrellite and thometzekite. A comparison is made with the sulphate bearing mineral natrochalcite. The position of the hydroxyl and water stretching vibrations are related to the strength of the hydrogen bond formed between the OH unit and the AsO(4)(3-) anion. Characteristic Raman spectra of the minerals enable the assignment of the bands to specific vibrational modes.

  3. Metal accumulating plants: Medium's role

    NASA Astrophysics Data System (ADS)

    Rabier, J.; Prudent, P.; Szymanska, B.; Mevy, J.-P.

    2003-05-01

    To evaluate phytoremediation potentialities by metal accumulation in tolerant plants, trials are carried out using in vitro cultures. Organie compounds influence on metal accumulation is studied with metals supplemented media. The tested compounds on zinc and lead absorption by Brassica juncea, are chelating agents (EDTA, citric acid) and soluble organic fractions of compost. EDTA seems to enhance the transfer of lead in plant but it is the opposite in the case of zinc. Citric acid stimulates root absorption for both zinc and lead. For the aqueous extracts of compost, variable effects are obtained according to the origin of compost (green wastes and food wastes). In'all tested conditions of cultures, zinc is mainly exported towards shoot while lead is stored in root.

  4. Multi-Channel Validation of Nonlinear Gyrokinetic Simulations in Alcator C-Mod I-mode Plasmas

    NASA Astrophysics Data System (ADS)

    Creely, A. J.

    2016-10-01

    New multi-channel validation of nonlinear gyrokinetic simulations (GYRO) is carried out for I-mode plasmas on Alcator C-Mod, utilizing heat fluxes, profile stiffness, and density and temperature fluctuations. I-mode plasmas are characterized by high energy confinement, similar to H-mode, but with L-mode-like particle confinement, making them favorable for reactors due to natural absence of ELMs, but without impurity accumulation [Whyte NF 2010]. At C-Mod, I-mode plasmas have been obtained across a wide range of plasma currents (Ip = 0.55-1.2MA) and magnetic fields (Bt = 2.8-8.0T). I-mode is also actively studied at ASDEX Upgrade, DIII-D and other tokamaks [Hubbard NF 2016]. Open questions remain regarding core transport in I-mode compared to L and H-mode, making validation studies in I-mode of great interest. Previous work at C-Mod found that ITG/TEM-scale GYRO simulations can match both electron and ion heat fluxes within error bars in I-mode [White PoP 2015], suggesting that multi-scale, cross-scale coupling effects [Howard PoP 2016] may be less important in I-mode than in L-mode. Adding the constraint of experimental perturbative heat diffusivity, however, revealed that ITG/TEM scale simulations do not adequately capture the high profile stiffness in I-mode [Creely NF 2016]. These results motivated more comprehensive comparisons of gyrokinetic simulations with I-mode plasmas. This talk expands upon past I-mode GYRO validation work to simultaneously constrain nonlinear gyrokinetic simulations with experimental electron and ion heat fluxes, electron temperature fluctuations measured with Correlation ECE, density fluctuations measured with Phase Contrast Imaging and reflectometry, and the temperature profile stiffness measured using partial sawtooth heat pulses. This work is supported by the US DOE under Grants DE-SC0006419 and DEFC02-99ER54512-CMOD.

  5. Mechanisms of intrahepatic triglyceride accumulation

    PubMed Central

    Ress, Claudia; Kaser, Susanne

    2016-01-01

    Hepatic steatosis defined as lipid accumulation in hepatocytes is very frequently found in adults and obese adolescents in the Western World. Etiologically, obesity and associated insulin resistance or excess alcohol intake are the most frequent causes of hepatic steatosis. However, steatosis also often occurs with chronic hepatitis C virus (HCV) infection and is also found in rare but potentially life-threatening liver diseases of pregnancy. Clinical significance and outcome of hepatic triglyceride accumulation are highly dependent on etiology and histological pattern of steatosis. This review summarizes current concepts of pathophysiology of common causes of hepatic steatosis, including non-alcoholic fatty liver disease (NAFLD), alcoholic fatty liver disease, chronic HCV infections, drug-induced forms of hepatic steatosis, and acute fatty liver of pregnancy. Regarding the pathophysiology of NAFLD, this work focuses on the close correlation between insulin resistance and hepatic triglyceride accumulation, highlighting the potential harmful effects of systemic insulin resistance on hepatic metabolism of fatty acids on the one side and the role of lipid intermediates on insulin signalling on the other side. Current studies on lipid droplet morphogenesis have identified novel candidate proteins and enzymes in NAFLD. PMID:26819531

  6. Simple dispersion estimate for single-section quantum-dash and quantum-dot mode-locked laser diodes.

    PubMed

    O Duill, Sean P; Murdoch, Stuart G; Watts, Regan T; Rosales, Ricardo; Ramdane, Abderrahim; Landais, Pascal; Barry, Liam P

    2016-12-15

    The optical outputs of single-section quantum-dash and quantum-dot mode-locked lasers (MLLs) are well known to exhibit strong group velocity dispersion. Based on careful measurements of the spectral phase of the pulses from these MLLs, we confirm that the difference in group delay between the modes at either end of the MLL spectrum equals the cavity round-trip time. This observation allows us to deduce an empirical formula relating the accumulated dispersion of the output pulse to the spectral extent and free-spectral range of the MLL. We find excellent agreement with previously reported dispersion measurements of both quantum-dash and quantum-dot MLLs over a wide range of operating conditions.

  7. Mixed-mode fracture of ceramics

    SciTech Connect

    Petrovic, J.J.

    1985-01-01

    The mixed-mode fracture behavior of ceramic materials is of importance for monolithic ceramics in order to predict the onset of fracture under generalized loading conditions and for ceramic composites to describe crack deflection toughening mechanisms. Experimental data on surface flaw mixed-mode fracture in various ceramics indicate that the flaw-plane normal stress at fracture decreases with increasing in-flaw-plane shear stress, although present data exhibit a fairly wide range in details of this sigma - tau relationship. Fracture from large cracks suggests that Mode II has a greater effect on Mode I fracture than Mode III. A comparison of surface flaw and large crack mixed-mode I-II fracture responses indicated that surface flaw behavior is influenced by shear resistance effects.

  8. OBSERVATIONS OF SAUSAGE MODES IN MAGNETIC PORES

    SciTech Connect

    Morton, R. J.; Erdelyi, R.; Jess, D. B.; Mathioudakis, M. E-mail: Robertus@sheffield.ac.uk

    2011-03-10

    We present here evidence for the observation of the magnetohydrodynamic (MHD) sausage modes in magnetic pores in the solar photosphere. Further evidence for the omnipresent nature of acoustic global modes is also found. The empirical decomposition method of wave analysis is used to identify the oscillations detected through a 4170 A 'blue continuum' filter observed with the Rapid Oscillations in the Solar Atmosphere (ROSA) instrument. Out of phase, periodic behavior in pore size and intensity is used as an indicator of the presence of magnetoacoustic sausage oscillations. Multiple signatures of the magnetoacoustic sausage mode are found in a number of pores. The periods range from as short as 30 s up to 450 s. A number of the magnetoacoustic sausage mode oscillations found have periods of 3 and 5 minutes, similar to the acoustic global modes of the solar interior. It is proposed that these global oscillations could be the driver of the sausage-type magnetoacoustic MHD wave modes in pores.

  9. Influencing factors on the mode transition in a dual-mode scramjet

    NASA Astrophysics Data System (ADS)

    Yan, Zhang; Bing, Chen; Gang, Liu; Baoxi, Wei; Xu, Xu

    2014-10-01

    An experimental investigation was performed to characterize the effects of fuel type, injector configuration, inflow total temperature and fuel injection distribution on the mode transition in a dual-mode scramjet combustor. High enthalpy vitiated air was heated to three total temperatures by the hydrogen-oxygen combustion, entering the isolator entrance at a Mach number of 2.0. Fuel was injected through a four-hole aero-ramp or transverse injector, and ignited by a gas-pilot flame. At an inflow stagnation condition of P0=0.85 MPa and T0=1200 K, three combustion modes, namely Pure Scram Mode, Dual-Mode Scram Mode and Dual-Mode Ram Mode, were classified through the wall pressure distributions, one-dimensional performance analysis, and optical visualization. Two critical fuel equivalence ratios were selected to divide three combustion modes. At the lower transition point, ERlc, the transition from Pure Scram Mode to Dual-Mode Scram Mode occurred corresponding to a normalized wall pressure at x/H=2.5 of 0.23; while at the upper transition point, ERuc, the transition from Dual-Mode Scram Mode to Dual-Mode Ram Mode occurred corresponding to a normalized wall pressure at x/H=2.5 of 0.34. The transition width, ERw, was defined as the difference of two transition points. In this limited range, the combustor was operating in the Dual-Mode Scram Mode. The ERuc was estimated based on the Rayleigh flow relation, and the applicability of the analytic equation was testified through a series of experiments with different boundary conditions. The experimental results showed that two transition points in the ethylene case were higher in ER than in the hydrogen case, and the measured ERuc of two fuels were all 2.5 times larger than the predicted values. However, two fuels had little difference on the transition width. Due to the angled injection, two transition points in the aero-ramp case were higher in ER than in the transverse injector case; while the influence of injector

  10. Large mode radius resonators

    NASA Technical Reports Server (NTRS)

    Harris, Michael R.

    1987-01-01

    Resonator configurations permitting operation with large mode radius while maintaining good transverse mode discrimination are considered. Stable resonators incorporating an intracavity telescope and unstable resonator geometries utilizing an output coupler with a Gaussian reflectivity profile are shown to enable large radius single mode laser operation. Results of heterodyne studies of pulsed CO2 lasers with large (11mm e sup-2 radius) fundamental mode sizes are presented demonstrating minimal frequency sweeping in accordance with the theory of laser-induced medium perturbations.

  11. Controls on pathogen species richness in plants introduced and native ranges: roles of residence time, range size and host traits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction of hosts to new geographic regions allows them to escape many pathogens, raising two questions. How quickly do introduced hosts accumulate pathogens? Do the same factors control pathogen accumulation as in the native range? We analyzed fungal and viral pathogen species richness on 124 p...

  12. Assessment of accumulated damage in circular tubes using nonlinear circumferential guided wave approach: A feasibility study.

    PubMed

    Deng, Mingxi; Gao, Guangjian; Xiang, Yanxun; Li, Mingliang

    2017-03-01

    The feasibility of using the nonlinear effect of primary Circumferential Guided Wave (CGW) propagation for assessing accumulated damage in circular tubes has been investigated. For a given circular tube, an appropriate mode pair of fundamental and double frequency CGWs is chosen to enable that the second harmonic of the primary wave mode can accumulate along the circumferential direction. After the given circular tube is subjected to compression-compression repeated loading for different numbers of loading cycles, the corresponding ultrasonic measurements are conducted. It is found that there is a direct correlation between the acoustic nonlinearity parameter measured with CGWs propagating through one full circumference and the level of accumulated damage in the circular tube. The experimental result obtained validates the feasibility for quantitative assessment of the accumulated damage in circular tubes using the effect of second-harmonic generation by CGW propagation.

  13. Few-mode fibers for mode division multiplexing transmission

    NASA Astrophysics Data System (ADS)

    Kubota, Hirokazu; Morioka, Toshio

    2012-01-01

    A study is presented of the fiber properties needed to achieve 10-mode multiplexing transmission. A combination of MIMO processing with optical LP mode separation is proposed to prevent the need for massive MIMO computation. The impact of mode crosstalk, differential mode delay, and the mode dependent loss of the few-mode fibers on mode multiplexing are discussed.

  14. Range Reference Notebook

    DTIC Science & Technology

    2006-10-15

    rifle grenade (inert), tin can lid, 15” tent peg 3 Table FRD-7. Fort Ritchie Sector 3 Representative Examples of Non-MEC Clutter Description 1/2...Appendix B—Indirect Fire Range Examples SITES ( ADI ) Adak Naval Air Facility, AK, Mitt Lake Mortar Range (FRI) Fort Ritchie...example range. B- ADI -1 Indirect-Fire Range,: Adak, AK, Mitt Lake Mortar Range Impact Area Site-Specific References – Adak NAF Foster Wheeler

  15. A Long-Range Precision Ranging System

    NASA Technical Reports Server (NTRS)

    Easterling, Mahlon

    1961-01-01

    A technique is presented that may be used for precision real-time continuous range measuring at long ranges. The technique uses a carrier that is phase modulated by a pseudo-random binary sequence. The characteristics of the sequence that make it acquirable are discussed. The general form of a receiver capable of tracking the carrier is given and is shown to be a kind of phase-locked loop. A two-loop system capable of tracking a pseudo-random sequence and its clock is given. The combination of the receiver and the sequence tracking system form a ranging receiver. The power division necessary between the carrier and the sidebands is shown to be determined by the noise bandwidths of the two tracking systems. The bandwidths necessary for tracking space probes and Earth satellites are given and some experiments in radar-tracking Earth satellites are described. Based on these experiments, estimates are made of the useful range of such a system in tracking space probes.

  16. Hardware test program for evaluation of baseline range/range rate sensor concept

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The Hardware Test Program for evaluation of the baseline range/range rate sensor concept was initiated 11 September 1984. This ninth report covers the period 12 May through 11 June 1885. A contract amendment adding a second phase has extended the Hardware Test Program through 10 December 1985. The objective of the added program phase is to establish range and range measurement accuracy and radar signature characteristics for a typical spacecraft target. Phase I of the Hardware Test Program was designed to reduce the risks associated with the Range/Range Rate (R/R) Sensor baseline design approach. These risks are associated with achieving the sensor performance required for the two modes of operation, the Interrupted CW (ICW) mode for initial acquisition and tracking to close-in ranges, and the CW mode, providing coverage during the final docking maneuver. The risks associated with these modes of operation have to do with the realization of adequate sensitivity to operate to their individual maximum ranges.

  17. The accumulation of nickel in human lungs

    SciTech Connect

    Edelman, D.A.; Roggli, V.L. )

    1989-05-01

    Using data from published studies, lung concentrations of nickel were compare for persons with and without occupational exposure to nickel. As expected, the concentrations were much higher for persons with occupational exposure. To estimate the effects of nickel-containing tobacco smoke and nickel in the ambient air on the amount of nickel accumulated in lungs over time, a model was derived that took into account various variables related to the deposition of nickel in lungs. The model predicted nickel concentrations that were in the range of those of persons without known nickel exposure. Nickel is a suspected carcinogen and has been associated with an increased risk of respiratory tract cancer among nickel workers. However, before the nickel content of cigarettes can be implicated in the etiology of lung cancer, further studies are needed to evaluate the independent effects of smoking and exposure to nickel.

  18. The accumulation of nickel in human lungs.

    PubMed Central

    Edelman, D A; Roggli, V L

    1989-01-01

    Using data from published studies, lung concentrations of nickel were compare for persons with and without occupational exposure to nickel. As expected, the concentrations were much higher for persons with occupational exposure. To estimate the effects of nickel-containing tobacco smoke and nickel in the ambient air on the amount of nickel accumulated in lungs over time, a model was derived that took into account various variables related to the deposition of nickel in lungs. The model predicted nickel concentrations that were in the range of those of persons without known nickel exposure. Nickel is a suspected carcinogen and has been associated with an increased risk of respiratory tract cancer among nickel workers. However, before the nickel content of cigarettes can be implicated in the etiology of lung cancer, further studies are needed to evaluate the independent effects of smoking and exposure to nickel. PMID:2759060

  19. Ablation of steel using picosecond laser pulses in burst mode

    NASA Astrophysics Data System (ADS)

    Lickschat, Peter; Demba, Alexander; Weissmantel, Steffen

    2017-02-01

    Results obtained in picosecond laser processing of steel applying the burst mode are presented. Using the burst mode, pulse trains, i.e., bursts, consisting of a number of picosecond pulses with an inter-pulse delay of 12.5 ns and 10 ps pulse duration are applied for material processing. Small cavities with sizes in the range of the laser beam diameter made by single-burst ablation are compared to quadratic cavities of 0.5 × 0.5 mm² produced by multiburst ablation and simultaneous scanning of the laser beam across the steel sample surface. The ablated volume per pulse within the burst was calculated either from the ablated volume per burst or from the ablation depth of the quadratic cavities. With the second to fourth pulses in the bursts, a reduction of the ablated volume per pulse in comparison with the first pulse in the bursts (i.e., to the use of single pulses) was found for both single- and multiburst ablation, which is assumed to be due to plasma shielding. By contrast, the ablated volume per pulse within the bursts increases for the fifth to eighth pulses. Heat accumulation effect and the influence of the heated plasma can be assumed to be the reason for these higher ablation rates. SEM micrographs also show that there is a higher melt ejection out of the laser processed area. This is indicated by the formation of bulges about the ablated area.

  20. Rabbit blastocysts accumulate [3H]prostaglandins in vitro.

    PubMed

    Jones, M A; Harper, M J

    1984-08-01

    Rabbit blastocysts obtained on days 5, 6, and 6.8 of pregnancy were incubated in vitro in Tyrode's buffer with 3H-labeled prostaglandins (PGs). Accumulation of PGs was studied, using Whatman GF/F filters to separate bound and free ligands. The uptake and efflux of [3H]PGs were studied as a function of PG type, incubation time, temperature, and effect of metabolic inhibitors as well as age and number of blastocysts. Blastocysts of the same age accumulated approximately the same amount of [3H]PGE2 and [3H]PGF2 alpha from their environment; however, there was no apparent saturation over a PG concentration range of 1-1000 nM. Both the uptake and efflux of PG were age dependent, with older blastocysts accumulating more PGs. Approximately 90% of the [3H]PGs appear to be transported into the blastocoelic fluid, with little PG remaining in the blastomeres. PG accumulation was relatively insensitive to azide, ouabain, cyanide, or bromcresol green, but was affected by incubation at 0 C or the addition of indomethacin (10 micrograms/ml). No catabolism of the accumulated PGs was observed. The release of PGE2 in general did not differ from that of PGF2 alpha, except on day 6.8 of pregnancy when PGE2 was released more rapidly than on day 6. We conclude that rabbit blastocysts can accumulate PGs from their environment, which may imply a storage potential in the blastocyst and release before implantation.

  1. Copper accumulation by stickleback nests containing spiggin.

    PubMed

    Pinho, G L L; Martins, C M G; Barber, I

    2016-07-01

    The three-spined stickleback is a ubiquitous fish of marine, brackish and freshwater ecosystems across the Northern hemisphere that presents intermediate sensitivity to copper. Male sticklebacks display a range of elaborate reproductive behaviours that include nest construction. To build the nests, each male binds nesting material together using an endogenous glycoprotein nesting glue, known as 'spiggin'. Spiggin is a cysteine-rich protein and, therefore, potentially binds heavy metals present in the environment. The aim of this study was to investigate the capacity of stickleback nests to accumulate copper from environmental sources. Newly built nests, constructed by male fish from polyester threads in laboratory aquaria, were immersed in copper solutions ranging in concentration from 21.1-626.6 μg Cu L(-1). Bundles of polyester threads from aquaria without male fish were also immersed in the same copper solutions. After immersion, nests presented higher amounts of copper than the thread bundles, indicating a higher capacity of nests to bind this metal. A significant, positive correlation between the concentration of copper in the exposure solution and in the exposed nests was identified, but there was no such relationship for thread bundles. Since both spiggin synthesis and male courtship behaviour are under the control of circulating androgens, we predicted that males with high courtship scores would produce and secrete high levels of the spiggin protein. In the present study, nests built by high courtship score males accumulated more copper than those built by low courtship score males. Considering the potential of spiggin to bind metals, the positive relationship between fish courtship and spiggin secretion seems to explain the higher amount of copper on the nests from the fish showing high behaviour scores. Further work is now needed to determine the consequences of the copper binding potential of spiggin in stickleback nests for the health and survival of

  2. Passive infrared ranging

    NASA Astrophysics Data System (ADS)

    Leonpacher, N. K.

    1983-12-01

    The range of an infrared source was estimated by analyzing the atmospheric absorption by CO2 in several wavelength intervals of its spectrum. These bandpasses were located at the edge of the CO2 absorption band near 2300 1/cm (4.3 micron). A specific algorithm to predict range was determined based on numerous computer generated spectra. When tested with these spectra, range estimates within 0.8 km were obtained for ranges between 0 and 18 km. Accuracy decreased when actual source spectra were tested. Although actual spectra were available only for ranges to 5 km, 63% of these spectra resulted in range estimates that were within 1.6 km of the actual range. Specific spectral conditions that affected the range predictions were found. Methods to correct the deficiencies were discussed. Errors from atmospheric variations, and the effects of background noise, were also investigated. Limits on accuracy and range resolution were determined.

  3. Streaming tearing mode

    NASA Technical Reports Server (NTRS)

    Shigeta, M.; Sato, T.; Dasgupta, B.

    1985-01-01

    The magnetohydrodynamic stability of streaming tearing mode is investigated numerically. A bulk plasma flow parallel to the antiparallel magnetic field lines and localized in the neutral sheet excites a streaming tearing mode more strongly than the usual tearing mode, particularly for the wavelength of the order of the neutral sheet width (or smaller), which is stable for the usual tearing mode. Interestingly, examination of the eigenfunctions of the velocity perturbation and the magnetic field perturbation indicates that the streaming tearing mode carries more energy in terms of the kinetic energy rather than the magnetic energy. This suggests that the streaming tearing mode instability can be a more feasible mechanism of plasma acceleration than the usual tearing mode instability.

  4. Observation of impurity accumulation and concurrent impurity influx in PBX

    SciTech Connect

    Sesnic, S.S.; Fonck, R.J.; Ida, K.; Bol, K.; Couture, P.; Gammel, G.; Kaita, R.; Kaye, S.; Kugel, H.; LeBlanc, B.

    1986-07-01

    Impurity studies in L- and H-mode discharges in PBX have shown that both types of discharges can evolve into either an impurity accumulative or nonaccumulative case. In a typical accumulative discharge, Zeff peaks in the center to values of about 5. The central metallic densities can be high, n/sub met//n/sub e/ approx. = 0.01, resulting in central radiated power densities in excess of 1 W/cm/sup 3/, consistent with bolometric estimates. The radial profiles of metals obtained independently from the line radiation in the soft x-ray and the VUV regions are very peaked. Concurrent with the peaking, an increase in the impurity influx coming from the edge of the plasma is observed. At the beginning of the accumulation phase the inward particle flux for titanium has values of 6 x 10/sup 10/ and 10 x 10/sup 10/ particles/cm/sup 2/s at minor radii of 6 and 17 cm. At the end of the accumulation phase, this particle flux is strongly increased to values of 3 x 10/sup 12/ and 1 x 10/sup 12/ particles/cm/sup 2/s. This increased flux is mainly due to influx from the edge of the plasma and to a lesser extent due to increased convective transport. Using the measured particle flux, an estimate of the diffusion coefficient D and the convective velocity v is obtained.

  5. Dynamically accumulated dose and 4D accumulated dose for moving tumors

    SciTech Connect

    Li Heng; Li Yupeng; Zhang Xiaodong; Li Xiaoqiang; Liu Wei; Gillin, Michael T.; Zhu, X. Ronald

    2012-12-15

    Purpose: The purpose of this work was to investigate the relationship between dynamically accumulated dose (dynamic dose) and 4D accumulated dose (4D dose) for irradiation of moving tumors, and to quantify the dose uncertainty induced by tumor motion. Methods: The authors established that regardless of treatment modality and delivery properties, the dynamic dose will converge to the 4D dose, instead of the 3D static dose, after multiple deliveries. The bounds of dynamic dose, or the maximum estimation error using 4D or static dose, were established for the 4D and static doses, respectively. Numerical simulations were performed (1) to prove the principle that for each phase, after multiple deliveries, the average number of deliveries for any given time converges to the total number of fractions (K) over the number of phases (N); (2) to investigate the dose difference between the 4D and dynamic doses as a function of the number of deliveries for deliveries of a 'pulsed beam'; and (3) to investigate the dose difference between 4D dose and dynamic doses as a function of delivery time for deliveries of a 'continuous beam.' A Poisson model was developed to estimate the mean dose error as a function of number of deliveries or delivered time for both pulsed beam and continuous beam. Results: The numerical simulations confirmed that the number of deliveries for each phase converges to K/N, assuming a random starting phase. Simulations for the pulsed beam and continuous beam also suggested that the dose error is a strong function of the number of deliveries and/or total deliver time and could be a function of the breathing cycle, depending on the mode of delivery. The Poisson model agrees well with the simulation. Conclusions: Dynamically accumulated dose will converge to the 4D accumulated dose after multiple deliveries, regardless of treatment modality. Bounds of the dynamic dose could be determined using quantities derived from 4D doses, and the mean dose difference

  6. Fine mode aerosol chemistry over a rural atmosphere near the north-east coast of Bay of Bengal in India

    NASA Astrophysics Data System (ADS)

    Adak, Anandamay; Chatterjee, Abhijit; Ghosh, Sanjay; Raha, Sibaji; Roy, Arindam

    2016-07-01

    A study was conducted on the chemical characterization of fine mode aerosol or PM2.5 over a rural atmosphere near the coast of Bay of Bengal in eastern India. Samples were collected and analyzed during March 2013 - February 2014. The concentration of PM2.5 was found span over a wide range from as low as 3 µg m-3 to as high as 180 µg m-3. The average concentration of PM2.5 was 62 µg m-3. Maximum accumulation of fine mode aerosol was observed during winter whereas minimum was observed during monsoon. Water soluble ionic species of fine mode aerosol were characterized over this rural atmosphere. In spite of being situated near the coast of Bay of Bengal, we observed significantly higher concentrations for anthropogenic species like ammonium and sulphate. The concentrations of these two species were much higher than the sea-salt aerosols. Ammonium and sulphate contributed around 30 % to the total fine mode aerosols. Even dust aerosol species like calcium also showed higher concentrations. Chloride to sodium ratio was found to be much less than that in standard sea-water indicating strong interaction between sea-salt and anthropogenic aerosols. Use of fertilizers in various crop fields and human and animal wastes significantly increased ammonium in fine mode aerosols. Dust aerosol species were accumulated in the atmosphere which could be due to transport of finer dust species from nearby metropolis or locally generated. Non-sea-sulphate and nitrate showed significant contributions in fine mode aerosols having both local and transported sources. Source apportionment shows prominent emission sources of anthropogenic aerosols from local anthropogenic activities and transported from nearby Kolkata metropolis as well.

  7. Splice loss requirements in multi-mode fiber mode-division-multiplex transmission links.

    PubMed

    Warm, Stefan; Petermann, Klaus

    2013-01-14

    We investigate numerically the influence of fiber splices and fiber connectors to the statistics of mode dependent loss (MDL) and multiple-input multiple-output (MIMO) outage capacity in mode multiplexed multi-mode fiber links. Our results indicate required splice losses much lower than currently feasible to achieve a reasonable outage capacity in long-haul transmission systems. Splice losses as low as 0.03dB may effectively lead to an outage of MIMO channels after only a few hundred kilometers transmission length. In a first approximation, the relative capacity solely depends on the accumulated splice loss and should be less than ≈ 2dB to ensure a relative capacity of 90%. We also show that discrete mode permutation (mixing) within the transmission line may effectively increase the maximum transmission distance by a factor of 5 for conventional splice losses.

  8. Neurodegeneration with brain iron accumulation (NBIA)

    MedlinePlus

    ... gov/ency/article/001225.htm Neurodegeneration with brain iron accumulation (NBIA) To use the sharing features on this page, please enable JavaScript. Neurodegeneration with brain iron accumulation (NBIA) are a group of rare nervous ...

  9. Racial Differences in Patterns of Wealth Accumulation

    ERIC Educational Resources Information Center

    Gittleman, Maury; Wolff, Edward N.

    2004-01-01

    The race differences in patterns of asset accumulations were examined using PSD data for 1984, 1989 and 1994. The results indicate that inheritances led to wealth accumulations among whites as compared to the African Americans.

  10. RADIO RANGING DEVICE

    DOEpatents

    Nieset, R.T.

    1961-05-16

    A radio ranging device is described. It utilizes a super regenerative detector-oscillator in which echoes of transmitted pulses are received in proper phase to reduce noise energy at a selected range and also at multiples of the selected range.

  11. Tau ranging revisited

    NASA Technical Reports Server (NTRS)

    Tausworthe, R. C.

    1987-01-01

    It is shown that a ranging receiver with a sufficient and reasonable number of correlators is competitive with the current sequential component ranging system by some 1.5 to 2.5 dB. The optimum transmitter code, the optimum receiver, and a near-maximum-lilelihood range-estimation algorithm are presented.

  12. Long Range Technology Planning.

    ERIC Educational Resources Information Center

    Ambron, Sueann, Ed.

    1986-01-01

    This summary of a meeting of the Apple Education Advisory Council, on long range technology plans at the state, county, district, and school levels, includes highlights from group discussions on future planning, staff development, and curriculum. Three long range technology plans at the state level are provided: Long Range Educational Technology…

  13. Alfv'enic Modes in HSX Stellarator

    NASA Astrophysics Data System (ADS)

    Deng, C.; Brower, D. L.; Spong, D. A.; Breizman, B. N.; Almagri, A. F.; Anderson, D. T.; Anderson, F. S. B.; Guttenfelder, W.; Likin, K.; Lore, J.; Lu, J.; Oh, S.; Radder, J. W.; Schmitt, J.; Zhai, K.

    2007-11-01

    Coherent, global fluctuations in the range of 20-120 kHz are observed for quasi-helically-symmetric, 2^nd Harmonic X-mode ECRH produced plasmas in HSX (BT=0.5T). Measurements and theory indicate that the mode with helicity m/n=1/1 is likely a global Alfv'en eigenmode (GAE) driven by nonthermal electrons. Under certain conditions, a satellite mode of same helicity is observed with frequency ˜20 kHz higher than the primary mode. Radial structure of both the primary and satellite modes are obtained by inversion of interferometry data showing peaks at different spatial locations. Finite pressure effects, even at low plasma beta, distort the Alfven continuum and mode frequency for these low m,n modes. For HSX operation at BT=1T with first Harmonic O-mode ECRH, the fast electron population is reduced and the mode is no longer observed. *Supported by USDOE contracts DE-FG03-01ER54615 and DE-FG02-93EE54222.

  14. Single-Mode VCSELs

    NASA Astrophysics Data System (ADS)

    Larsson, Anders; Gustavsson, Johan S.

    The only active transverse mode in a truly single-mode VCSEL is the fundamental mode with a near Gaussian field distribution. A single-mode VCSEL produces a light beam of higher spectral purity, higher degree of coherence and lower divergence than a multimode VCSEL and the beam can be more precisely shaped and focused to a smaller spot. Such beam properties are required in many applications. In this chapter, after discussing applications of single-mode VCSELs, we introduce the basics of fields and modes in VCSELs and review designs implemented for single-mode emission from VCSELs in different materials and at different wavelengths. This includes VCSELs that are inherently single-mode as well as inherently multimode VCSELs where higher-order modes are suppressed by mode selective gain or loss. In each case we present the current state-of-the-art and discuss pros and cons. At the end, a specific example with experimental results is provided and, as a summary, the most promising designs based on current technologies are identified.

  15. 47 CFR 32.3100 - Accumulated depreciation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Accumulated depreciation. 32.3100 Section 32... Accumulated depreciation. (a) This account shall include the accumulated depreciation associated with the... with depreciation amounts concurrently charged to Account 6561, Depreciation...

  16. Density Gradient Dependent Helicon Modes

    NASA Astrophysics Data System (ADS)

    Panevsky, Martin; Bengtson, Roger

    2002-11-01

    Radially localized helicon modes have been proposed to provide a fuller description of helicon discharges over a wide span of operating conditions and gas types [1]. These plasma modes could be of vital importance to the VASIMR engine. They depend on a radial density gradient and appear to operate over a range of frequencies inaccessible to traditional helicon discharges. Our work focuses on confirming experimentally the existence and properties of these helicon modes in Argon, Helium, and Hydrogen. We investigate the density profile, power deposition, wavefields, and dispersion relation of the new helicon modes which differ substantially from the properties of the traditional helicon plasma. We are using a set of dual half-turn helical antennas driven at 13.56 MHz. Our diagnostics includes a system for monitoring the plasma impedance, a set of Langmuir probes, a set of magnetic probes, as well as sensors for monitoring the pressure and DC magnetic field. *Work supported in part by Advanced Space Propulsion Lab, Johnson Space Center, NASA [1] B. N. Breizman and A. V. Arefiev, Phys. Rev. 84, 3863 (2000)

  17. Microstructural effects on fracture toughness of polycrystalline ceramics in combined mode I and mode II loading

    NASA Technical Reports Server (NTRS)

    Singh, D.; Shetty, D. K.

    1988-01-01

    Fracture toughness of polycrystalline alumina and ceria partially-stabilized tetragonal zirconia (CeO2-TZP) ceramics were assessed in combined mode I and mode II loading using precracked disk specimens in diametral compression. Stress states ranging from pure mode I, combined mode I and mode II, and pure mode II were obtained by aligning the center crack at specific angles relative to the loading diameter. The resulting mixed-mode fracture toughness envelope showed significant deviation to higher fracture toughness in mode II relative to the predictions of the linear elastic fracture mechanics theory. Critical comparison with corresponding results on soda-lime glass and fracture surface observations showed that crack surface resistance arising from grain interlocking and abrasion was the main source of the increased fracture toughness in mode II loading of the polycrystalline ceramics. The normalized fracture toughness for pure mode II loading, (KII/KIc), increased with increasing grain size for the CeO2-TZP ceramics. Quantitative fractography confirmed an increased percentage of transgranular fracture of the grains in mode II loading.

  18. Telemetry Ranging: Signal Processing

    NASA Astrophysics Data System (ADS)

    Hamkins, J.; Kinman, P.; Xie, H.; Vilnrotter, V.; Dolinar, S.

    2016-02-01

    This article describes the details of the signal processing used in a telemetry ranging system in which timing information is extracted from the downlink telemetry signal in order to compute spacecraft range. A previous article describes telemetry ranging concepts and architecture, which are a slight variation of a scheme published earlier. As in that earlier work, the telemetry ranging concept eliminates the need for a dedicated downlink ranging signal to communicate the necessary timing information. The present article describes the operation and performance of the major receiver functions on the spacecraft and the ground --- many of which are standard tracking loops already in use in JPL's flight and ground radios --- and how they can be used to provide the relevant information for making a range measurement. It also describes the implementation of these functions in software, and performance of an end-to-end software simulation of the telemetry ranging system.

  19. Ectoine accumulation in Brevibacterium epidermis.

    PubMed

    Onraedt, Annelies; De Muynck, Cassandra; Walcarius, Bart; Soetaert, Wim; Vandamme, Erick

    2004-10-01

    As a halotolerant bacterial species, Brevibacterium epidermis DSM 20659 can grow at relatively high salinity, tolerating up to 2 M NaCl. It synthesizes ectoine and the intracellular content increases with the medium salinity, with a maximum of 0.14 g ectoine/g CDW at 1 M NaCl. Sugar-stressed cells do not synthesize ectoine. Ectoine synthesis is also affected by the presence of external osmolytes. Added betaine is taken up and completely replaced ectoine, while L-proline is only temporarily accumulated after which ectoine is synthesized. The strain can metabolize ectoine; L-glutamate is a better carbon source for ectoine synthesis than L-aspartate.

  20. Telemetry-Based Ranging

    NASA Technical Reports Server (NTRS)

    Hamkins, Jon; Vilnrotter, Victor A.; Andrews, Kenneth S.; Shambayati, Shervin

    2011-01-01

    A telemetry-based ranging scheme was developed in which the downlink ranging signal is eliminated, and the range is computed directly from the downlink telemetry signal. This is the first Deep Space Network (DSN) ranging technology that does not require the spacecraft to transmit a separate ranging signal. By contrast, the evolutionary ranging techniques used over the years by NASA missions, including sequential ranging (transmission of a sequence of sinusoids) and PN-ranging (transmission of a pseudo-noise sequence) whether regenerative (spacecraft acquires, then regenerates and retransmits a noise-free ranging signal) or transparent (spacecraft feeds the noisy demodulated uplink ranging signal into the downlink phase modulator) relied on spacecraft power and bandwidth to transmit an explicit ranging signal. The state of the art in ranging is described in an emerging CCSDS (Consultative Committee for Space Data Systems) standard, in which a pseudo-noise (PN) sequence is transmitted from the ground to the spacecraft, acquired onboard, and the PN sequence is coherently retransmitted back to the ground, where a delay measurement is made between the uplink and downlink signals. In this work, the telemetry signal is aligned with the uplink PN code epoch. The ground station computes the delay between the uplink signal transmission and the received downlink telemetry. Such a computation is feasible because symbol synchronizability is already an integral part of the telemetry design. Under existing technology, the telemetry signal cannot be used for ranging because its arrival-time information is not coherent with any Earth reference signal. By introducing this coherence, and performing joint telemetry detection and arrival-time estimation on the ground, a high-rate telemetry signal can provide all the precision necessary for spacecraft ranging.

  1. Whispering gallery mode sensors

    PubMed Central

    Foreman, Matthew R.; Swaim, Jon D.; Vollmer, Frank

    2015-01-01

    We present a comprehensive overview of sensor technology exploiting optical whispering gallery mode (WGM) resonances. After a short introduction we begin by detailing the fundamental principles and theory of WGMs in optical microcavities and the transduction mechanisms frequently employed for sensing purposes. Key recent theoretical contributions to the modeling and analysis of WGM systems are highlighted. Subsequently we review the state of the art of WGM sensors by outlining efforts made to date to improve current detection limits. Proposals in this vein are numerous and range, for example, from plasmonic enhancements and active cavities to hybrid optomechanical sensors, which are already working in the shot noise limited regime. In parallel to furthering WGM sensitivity, efforts to improve the time resolution are beginning to emerge. We therefore summarize the techniques being pursued in this vein. Ultimately WGM sensors aim for real-world applications, such as measurements of force and temperature, or alternatively gas and biosensing. Each such application is thus reviewed in turn, and important achievements are discussed. Finally, we adopt a more forward-looking perspective and discuss the outlook of WGM sensors within both a physical and biological context and consider how they may yet push the detection envelope further. PMID:26973759

  2. On-chip optical mode exchange using tapered directional coupler

    PubMed Central

    Zhang, Zhonglai; Hu, Xiao; Wang, Jian

    2015-01-01

    We present an on-chip optical mode exchange between two multiplexed modes by using tapered directional couplers on silicon-on-insulator platform. The device consisting of mode multiplexing and mode exchange is compact with relatively large fabrication error tolerance. The simulation results show efficient higher order mode excitation and mode exchange. A low excess loss less than 0.5 dB and high extinction ratio larger than 15 dB over 10 nm wavelength range from 1535 to 1545 nm are achieved. PMID:26530728

  3. Model for the incorporation of plant detritus within clastic accumulating interdistributary bays

    SciTech Connect

    Gastaldo, R.A.; McCarroll, S.M.; Douglass, D.P.

    1985-01-01

    Plant-bearing clastic lithologies interpreted as interdistributary bay deposits are reported from rocks Devonian to Holocene in age. Often, these strata preserve accumulations of discrete, laterally continuous leaf beds or coaly horizons. Investigations within two modern inter-distributary bays in the lower delta plain of the Mobile Delta, Alabama have provided insight into the phytotaphonomic processes responsible for the generation of carbonaceous lithologies, coaly horizons and laterally continuous leaf beds. Delvan and Chacalooche Bays lie adjacent to the Tensaw River distributary channel and differ in the mode of clastic and plant detrital accumulation. Delvan Bay, lying west of the distributary channel, is accumulating detritus solely by overbank deposition. Chacaloochee Bay, lying east of the channel, presently is accumulating detritus by active crevasse-splay activity. Plant detritus is accumulating as transported assemblages in both bays, but the mode of preservation differs. In Delvan Bay, the organic component is highly degraded and incorporated within the clastic component resulting in a carbonaceous silt. Little identifiable plant detritus can be recovered. On the other hand, the organic component in Chacaloochee Bay is accumulating in locally restricted allochthonous peat deposits up to 2 m in thickness, and discrete leaf beds generated by flooding events. In addition, autochthonous plant accumulations occur on subaerially and aerially exposed portions of the crevasse. The resultant distribution of plant remains is a complicated array of transported and non-transported organics.

  4. Revisiting Modes of energy generation in sulfate reducing bacteria

    SciTech Connect

    Joachimiak, Marcin; Chakraborty, Romy; Zhou, Aifen; Fortney, Julian; Geller, Jil; Wall, Judy; Zhou, Jizhong; Arkin, Adam; Hazen, Terry; Keasling, Jay; Chhabra, Swapnil

    2010-05-17

    Sulfate reducing bacteria (SRB) play an important role in global sulfur and carbon cycling through their ability to completely mineralize organic matter while respiring sulfate to hydrogen sulfide. They are ubiquitous in anaerobic environments and have the ability to reduce toxic metals like Cr(VI) and U(VI). While SRB have been studied for over three decades, bioenergetic modes of this group of microbes are poorly understood. Desulfovibrio vulgaris strain Hildenborough (DvH) has served as a model SRB over the last decade with the accumulation of transcriptomic, proteomic and metabolic data under a wide variety of stressors. To further investigate the three hypothesized modes of energy generation in this anaerobe we conducted a systematic study involving multiple electron donor and acceptor combinations for growth. DvH was grown at 37oC in a defined medium with (a) lactate + thiosulfate, (b) lactate + sulfite (c) lactate + sulfate, (d) pyruvate + sulfate, (e) H2 + acetate + sulfate, (f) formate + acetate + sulfate, g) formate + sulfate and (h) pyruvate fermentation. Cells were harvested at mid-log phase of growth for all conditions for transcriptomics, when the optical density at 600nm was in the range 0.42-0.5. Initial results indicate that cells grown on lactate do not appear to significantly differentiate their gene expression profiles when presented with different electron acceptors. These profiles however differ significantly from those observed during growth with other electron donors such as H2 and formate, as well as during fermentative growth. Together the gene expression changes in the presence of different electron donors provide insights into the ability of DvH to differentially reduce metals such as Cr(VI). Here we present revised modes of energy generation in DvH in light of this new transcriptomic evidence.

  5. Current Range Safety Capabilities

    DTIC Science & Technology

    1994-02-01

    mission objectives, to prevent personnel injury , to minimize property damage, and to preclude incidents having the potential for international... high -speed film cameras in 16 mm, 35 mm, and 70 mm formats. These cameras can operate at frame rates from 6 to 40,000 frames per second. * Bowen ribbon...90, 180, and 360 frames per second. * Ultra- high -speed cameras capable of rates up to 4,500,000 frames per second in the framing mode or write records

  6. Damage accumulation in neon implanted silicon

    SciTech Connect

    Oliviero, E.; Peripolli, S.; Amaral, L.; Fichtner, P. F. P.; Beaufort, M. F.; Barbot, J. F.; Donnelly, S. E.

    2006-08-15

    Damage accumulation in neon-implanted silicon with fluences ranging from 5x10{sup 14} to 5x10{sup 16} Ne cm{sup -2} has been studied in detail. As-implanted and annealed samples were investigated by Rutherford backscattering spectrometry under channeling conditions and by transmission electron microscopy in order to quantify and characterize the lattice damage. Wavelength dispersive spectrometry was used to obtain the relative neon content stored in the matrix. Implantation at room temperature leads to the amorphization of the silicon while a high density of nanosized bubbles is observed all along the ion distribution, forming a uniform and continuous layer for implantation temperatures higher than 250 deg.C. Clusters of interstitial defects are also present in the deeper part of the layer corresponding to the end of range of ions. After annealing, the samples implanted at temperatures below 250 deg.C present a polycrystalline structure with blisters at the surface while in the other samples coarsening of bubbles occurs and nanocavities are formed together with extended defects identified as (311) defects. The results are discussed in comparison to the case of helium-implanted silicon and in the light of radiation-enhanced diffusion.

  7. Ordinary electromagnetic mode instability

    NASA Technical Reports Server (NTRS)

    Cheng, C. Z.

    1974-01-01

    The instability of the ordinary electromagnetic mode propagating perpendicular to an external magnetic field is studied for a single-species plasma with ring velocity distribution. The marginal instability boundaries for both the purely growing mode and the propagating growing modes are calculated from the instability criteria. The dispersion characteristics for various sets of plasma parameters are also given. The typical growth rates are of the order of the cyclotron frequency.

  8. Guidelines for Waste Accumulation Areas (WAAs)

    SciTech Connect

    Not Available

    1991-07-01

    The purpose of this document is to set conditions for establishing and maintaining areas for the accumulation of hazardous waste at LBL. Areas designed for accumulation of these wastes in quantities greater than 100 kg (220 lb) per month of solid waste or 55 gallons per month of liquid waste are called Waste Accumulation Areas (WAAs). Areas designed for accumulation of wastes in smaller amounts are called Satellite Accumulation Areas (SAAs). This document provides guidelines for employee and organizational responsibilities for WAAs; constructing a WAA; storing waste in a WAA; operating and maintaining a WAA, and responding to spills in a WAA. 4 figs.

  9. Micron Accurate Absolute Ranging System: Range Extension

    NASA Technical Reports Server (NTRS)

    Smalley, Larry L.; Smith, Kely L.

    1999-01-01

    The purpose of this research is to investigate Fresnel diffraction as a means of obtaining absolute distance measurements with micron or greater accuracy. It is believed that such a system would prove useful to the Next Generation Space Telescope (NGST) as a non-intrusive, non-contact measuring system for use with secondary concentrator station-keeping systems. The present research attempts to validate past experiments and develop ways to apply the phenomena of Fresnel diffraction to micron accurate measurement. This report discusses past research on the phenomena, and the basis of the use Fresnel diffraction distance metrology. The apparatus used in the recent investigations, experimental procedures used, preliminary results are discussed in detail. Continued research and equipment requirements on the extension of the effective range of the Fresnel diffraction systems is also described.

  10. SAMPEX special pointing mode

    NASA Technical Reports Server (NTRS)

    Markley, F. Landis; Flatley, Thomas W.; Leoutsakos, Theodore

    1995-01-01

    A new pointing mode has been developed for the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) spacecraft. This pointing mode orients the instrument boresights perpendicular to the field lines of the Earth's magnetic field in regions of low field strength and parallel to the field lines in regions of high field strength, to allow better characterization of heavy ions trapped by the field. The new mode uses magnetometer signals and is algorithmically simpler than the previous control mode, but it requires increased momentum wheel activity. It was conceived, designed, tested, coded, uplinked to the spacecraft, and activated in less than seven months.

  11. Compressive laser ranging.

    PubMed

    Babbitt, Wm Randall; Barber, Zeb W; Renner, Christoffer

    2011-12-15

    Compressive sampling has been previously proposed as a technique for sampling radar returns and determining sparse range profiles with a reduced number of measurements compared to conventional techniques. By employing modulation on both transmission and reception, compressive sensing in ranging is extended to the direct measurement of range profiles without intermediate measurement of the return waveform. This compressive ranging approach enables the use of pseudorandom binary transmit waveforms and return modulation, along with low-bandwidth optical detectors to yield high-resolution ranging information. A proof-of-concept experiment is presented. With currently available compact, off-the-shelf electronics and photonics, such as high data rate binary pattern generators and high-bandwidth digital optical modulators, compressive laser ranging can readily achieve subcentimeter resolution in a compact, lightweight package.

  12. Improved ranging systems

    NASA Technical Reports Server (NTRS)

    Young, Larry E.

    1989-01-01

    Spacecraft range measurements have provided the most accurate tests, to date, of some relativistic gravitational parameters, even though the measurements were made with ranging systems having error budgets of about 10 meters. Technology is now available to allow an improvement of two orders of magnitude in the accuracy of spacecraft ranging. The largest gains in accuracy result from the replacement of unstable analog components with high speed digital circuits having precisely known delays and phase shifts.

  13. Automatic range selector

    DOEpatents

    McNeilly, Clyde E.

    1977-01-04

    A device is provided for automatically selecting from a plurality of ranges of a scale of values to which a meter may be made responsive, that range which encompasses the value of an unknown parameter. A meter relay indicates whether the unknown is of greater or lesser value than the range to which the meter is then responsive. The rotatable part of a stepping relay is rotated in one direction or the other in response to the indication from the meter relay. Various positions of the rotatable part are associated with particular scales. Switching means are sensitive to the position of the rotatable part to couple the associated range to the meter.

  14. 3-D Mixed Mode Delamination Fracture Criteria - An Experimentalist's Perspective

    NASA Technical Reports Server (NTRS)

    Reeder, James R.

    2006-01-01

    Many delamination failure criteria based on fracture toughness have been suggested over the past few decades, but most only covered the region containing mode I and mode II components of loading because that is where toughness data existed. With new analysis tools, more 3D analyses are being conducted that capture a mode III component of loading. This has increased the need for a fracture criterion that incorporates mode III loading. The introduction of a pure mode III fracture toughness test has also produced data on which to base a full 3D fracture criterion. In this paper, a new framework for visualizing 3D fracture criteria is introduced. The common 2D power law fracture criterion was evaluated to produce unexpected predictions with the introduction of mode III and did not perform well in the critical high mode I region. Another 2D criterion that has been shown to model a wide range of materials well was used as the basis for a new 3D criterion. The new criterion is based on assumptions that the relationship between mode I and mode III toughness is similar to the relation between mode I and mode II and that a linear interpolation can be used between mode II and mode III. Until mixed-mode data exists with a mode III component of loading, 3D fracture criteria cannot be properly evaluated, but these assumptions seem reasonable.

  15. Failure modes in surface micromachined microelectromechanical actuators

    SciTech Connect

    Miller, S.L.; Rodgers, M.S.; LaVigne, G.; Sniegowski, J.J.; Clews, P.; Tanner, D.M.; Peterson, K.A.

    1998-03-01

    In order for the rapidly emerging field of MicroElectroMechanical Systems (MEMS) to meet its extraordinary expectations regarding commercial impact, issues pertaining to how they fail must be understood. The authors identify failure modes common to a broad range of MEMS actuators, including adhesion (stiction) and friction induced failures caused by improper operational methods, mechanical instabilities, and electrical instabilities. Demonstrated methods to mitigate these failure modes include implementing optimized designs, model based operational methods, and chemical surface treatments.

  16. Agriculture, Forestry, Range Resources

    NASA Technical Reports Server (NTRS)

    Crea, W. J., Jr.

    1973-01-01

    Significant results obtained from ERTS-1 observations of agriculture, forestry, and range resources are summarized. Four major parts are covered: (1) crop classification and mensuration; (2) timber and range resources survey and classification; (3) soil survey and mapping; and (4) subdiscipline areas.

  17. Laser ranging data analysis

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Near real-time Lageos laser ranging data are analyzed in terms of range bias, time bias, and internal precision, and estimates for earth orientation parameters X(sub p), Y(sub p), and UT1 are obtained. The results of these analyses are reported in a variety of formats. Copies of monthly summaries from November, 1986 through November, 1987 are included.

  18. Long Range Facilities Planning

    DTIC Science & Technology

    1982-04-01

    Richard Muther range facilities Many alterna- analysis indi- cated that if NASSCO ever expected to surpass its output of the last several years, current...Marine Engineers (SNAME) SP-1 Panel Meeting. The Maritime Administration had Richard Muther (an authority on long range facility planning) address a

  19. Home range and travels

    USGS Publications Warehouse

    Stickel, L.F.; King, John A.

    1968-01-01

    The concept of home range was expressed by Seton (1909) in the term 'home region,' which Burr (1940, 1943) clarified with a definition of home range and exemplified in a definitive study of Peromyscus in the field. Burt pointed out the ever-changing characteristics of home-range area and the consequent absence of boundaries in the usual sense--a finding verified by investigators thereafter. In the studies summarized in this paper, sizes of home ranges of Peromyscus varied within two magnitudes, approximately from 0.1 acre to ten acres, in 34 studies conducted in a variety of habitats from the seaside dunes of Florida to the Alaskan forests. Variation in sizes of home ranges was correlated with both environmental and physiological factors; with habitat it was conspicuous, both in the same and different regions. Food supply also was related to size of home range, both seasonally and in relation to habitat. Home ranges generally were smallest in winter and largest in spring, at the onset of the breeding season. Activity and size also were affected by changes in weather. Activity was least when temperatures were low and nights were bright. Effects of rainfall were variable. Sizes varied according to sex and age; young mice remained in the parents' range until they approached maturity, when they began to travel more widely. Adult males commonly had larger home ranges than females, although there were a number of exceptions. An inverse relationship between population density and size of home range was shown in several studies and probably is the usual relationship. A basic need for activity and exploration also appeared to influence size of home range. Behavior within the home range was discussed in terms of travel patterns, travels in relation to home sites and refuges, territory, and stability of size of home range. Travels within the home range consisted of repeated use of well-worn trails to sites of food, shelter, and refuge, plus more random exploratory travels

  20. Terahertz normal mode relaxation in pentaerythritol tetranitrate.

    PubMed

    Pereverzev, Andrey; Sewell, Thomas D

    2011-01-07

    Normal vibrational modes for a three-dimensional defect-free crystal of the high explosive pentaerythritol tetranitrate were obtained in the framework of classical mechanics using a previously published unreactive potential-energy surface [J. Phys. Chem. B 112, 734 (2008)]. Using these results the vibrational density of states was obtained for the entire vibrational frequency range. Relaxation of selectively excited terahertz-active modes was studied using isochoric-isoergic (NVE) molecular dynamics simulations for energy and density conditions corresponding to room temperature and atmospheric pressure. Dependence of the relaxation time on the initial modal excitation was considered for five excitation energies between 10 and 500 kT and shown to be relatively weak. The terahertz absorption spectrum was constructed directly using linewidths obtained from the relaxation times of the excited modes for the case of 10 kT excitation. The spectrum shows reasonably good agreement with experimental results. Dynamics of redistribution of the excited mode energy among the other normal modes was also studied. The results indicate that, for the four terahertz-active initially excited modes considered, there is a small subset of zero wave vector (k = 0) modes that preferentially absorb the energy on a few-picosecond time scale. The majority of the excitation energy, however, is transferred nonspecifically to the bath modes of the system.

  1. Sequential biases in accumulating evidence

    PubMed Central

    Huggins, Richard; Dogo, Samson Henry

    2015-01-01

    Whilst it is common in clinical trials to use the results of tests at one phase to decide whether to continue to the next phase and to subsequently design the next phase, we show that this can lead to biased results in evidence synthesis. Two new kinds of bias associated with accumulating evidence, termed ‘sequential decision bias’ and ‘sequential design bias’, are identified. Both kinds of bias are the result of making decisions on the usefulness of a new study, or its design, based on the previous studies. Sequential decision bias is determined by the correlation between the value of the current estimated effect and the probability of conducting an additional study. Sequential design bias arises from using the estimated value instead of the clinically relevant value of an effect in sample size calculations. We considered both the fixed‐effect and the random‐effects models of meta‐analysis and demonstrated analytically and by simulations that in both settings the problems due to sequential biases are apparent. According to our simulations, the sequential biases increase with increased heterogeneity. Minimisation of sequential biases arises as a new and important research area necessary for successful evidence‐based approaches to the development of science. © 2015 The Authors. Research Synthesis Methods Published by John Wiley & Sons Ltd. PMID:26626562

  2. Natural radionuclide accumulation by raindrops

    NASA Astrophysics Data System (ADS)

    Gusev, Anatoly; Martin, Inacio; Shkevov, Rumen; Alves, Mauro

    2016-07-01

    The laboratory of environmental radiation of ITA (São José dos Campos, 23°11'11″S, 45°52'43″W, 650 MAMSL) performs simultaneous monitoring of a natural radiation background and meteorological parameters. A time resolution of up to 1 minute allows a detailed comparison of changes in meteorological parameters with those of a concentration of ambient radon progenies in the atmosphere. Results of a study of variation of a fallout of radon progenies ^{214}Pb and ^{214}Bi concomitanting rainfalls are present. The radionuclide fallout rate is reconstructed from the observed gamma rate through a simulation of the first kind Volterra integral equation with difference kernel, determined by ratio of precipitating rates of 214Pb and 214Bi and their decay half times. An original straightforward step-by-step procedure was used for the numerical solution of the equation. The radionuclide concentration in the rainwater is calculated as a ratio of the reconstructed fallout to the measured rainfall. It was observed that the radionuclide fallout rate increases as the rainfall one in approximately power 0.6, i.e. the same as the mean raindrop volume. The concentration thereafter decreases as the rainfall rate in power 0.4. A numerical simulation of the process of accumulation of the radionuclides during diffusion and coalescence drop growth and aerosol scavenging during a passage from a cloud to the ground was performed. The results of the simulations agree with the experimental data.

  3. Global mirror modes in the magnetosheath

    SciTech Connect

    Johnson, J.R.; Cheng, C.Z.

    1996-05-01

    A global stability analysis of mirror modes in the magnetosheath is presented. The analysis is based upon the kinetic-MHD formulation which includes relevant kinetic effects such as Landau resonance and gradient drift effects related to inhomogeneities in the background density, temperature, pressure and its anisotropy, magnetic field, and plasma flow velocity. Pressure anisotropy provides the free energy for the global mirror mode. The local theory of mirror modes predicts purely growing modes confined in the unstable magnetosheath region; however, the nonlocal theory that includes the effects of gradients and plasma flow predicts modes with real frequencies which propagate with the flow from the magnetosheath toward the magnetopause boundary. The real frequency is on the order of a combination of the diamagnetic drift frequency and the Doppler shift frequency associated with the plasma flow. The diamagnetic drift frequency provides a wave phase velocity in the direction of the magnetopause so that wave energy accumulates against the magnetopause boundary, and the amplitude is skewed in that direction. On the other hand, plasma flow also gives rise to a real phase velocity, but the phase velocity is smaller than the flow velocity. As a result, the wave amplitude is increased in the wake of the plasma flow and piles up against the bow shock boundary.

  4. Response times from ensembles of accumulators

    PubMed Central

    Zandbelt, Bram; Purcell, Braden A.; Palmeri, Thomas J.; Logan, Gordon D.; Schall, Jeffrey D.

    2014-01-01

    Decision-making is explained by psychologists through stochastic accumulator models and by neurophysiologists through the activity of neurons believed to instantiate these models. We investigated an overlooked scaling problem: How does a response time (RT) that can be explained by a single model accumulator arise from numerous, redundant accumulator neurons, each of which individually appears to explain the variability of RT? We explored this scaling problem by developing a unique ensemble model of RT, called e pluribus unum, which embodies the well-known dictum “out of many, one.” We used the e pluribus unum model to analyze the RTs produced by ensembles of redundant, idiosyncratic stochastic accumulators under various termination mechanisms and accumulation rate correlations in computer simulations of ensembles of varying size. We found that predicted RT distributions are largely invariant to ensemble size if the accumulators share at least modestly correlated accumulation rates and RT is not governed by the most extreme accumulators. Under these regimes the termination times of individual accumulators was predictive of ensemble RT. We also found that the threshold measured on individual accumulators, corresponding to the firing rate of neurons measured at RT, can be invariant with RT but is equivalent to the specified model threshold only when the rate correlation is very high. PMID:24550315

  5. Mode decomposition evolution equations

    PubMed Central

    Wang, Yang; Wei, Guo-Wei; Yang, Siyang

    2011-01-01

    Partial differential equation (PDE) based methods have become some of the most powerful tools for exploring the fundamental problems in signal processing, image processing, computer vision, machine vision and artificial intelligence in the past two decades. The advantages of PDE based approaches are that they can be made fully automatic, robust for the analysis of images, videos and high dimensional data. A fundamental question is whether one can use PDEs to perform all the basic tasks in the image processing. If one can devise PDEs to perform full-scale mode decomposition for signals and images, the modes thus generated would be very useful for secondary processing to meet the needs in various types of signal and image processing. Despite of great progress in PDE based image analysis in the past two decades, the basic roles of PDEs in image/signal analysis are only limited to PDE based low-pass filters, and their applications to noise removal, edge detection, segmentation, etc. At present, it is not clear how to construct PDE based methods for full-scale mode decomposition. The above-mentioned limitation of most current PDE based image/signal processing methods is addressed in the proposed work, in which we introduce a family of mode decomposition evolution equations (MoDEEs) for a vast variety of applications. The MoDEEs are constructed as an extension of a PDE based high-pass filter (Europhys. Lett., 59(6): 814, 2002) by using arbitrarily high order PDE based low-pass filters introduced by Wei (IEEE Signal Process. Lett., 6(7): 165, 1999). The use of arbitrarily high order PDEs is essential to the frequency localization in the mode decomposition. Similar to the wavelet transform, the present MoDEEs have a controllable time-frequency localization and allow a perfect reconstruction of the original function. Therefore, the MoDEE operation is also called a PDE transform. However, modes generated from the present approach are in the spatial or time domain and can be

  6. Excursions through KK modes

    NASA Astrophysics Data System (ADS)

    Furuuchi, Kazuyuki

    2016-07-01

    In this article we study Kaluza-Klein (KK) dimensional reduction of massive Abelian gauge theories with charged matter fields on a circle. Since local gauge transformations change position dependence of the charged fields, the decomposition of the charged matter fields into KK modes is gauge dependent. While whole KK mass spectrum is independent of the gauge choice, the mode number depends on the gauge. The masses of the KK modes also depend on the field value of the zero-mode of the extra dimensional component of the gauge field. In particular, one of the KK modes in the KK tower of each massless 5D charged field becomes massless at particular values of the extra-dimensional component of the gauge field. When the extra-dimensional component of the gauge field is identified with the inflaton, this structure leads to recursive cosmological particle productions.

  7. Zero-mode waveguides

    DOEpatents

    Levene, Michael J.; Korlach, Jonas; Turner, Stephen W.; Craighead, Harold G.; Webb, Watt W.

    2007-02-20

    The present invention is directed to a method and an apparatus for analysis of an analyte. The method involves providing a zero-mode waveguide which includes a cladding surrounding a core where the cladding is configured to preclude propagation of electromagnetic energy of a frequency less than a cutoff frequency longitudinally through the core of the zero-mode waveguide. The analyte is positioned in the core of the zero-mode waveguide and is then subjected, in the core of the zero-mode waveguide, to activating electromagnetic radiation of a frequency less than the cut-off frequency under conditions effective to permit analysis of the analyte in an effective observation volume which is more compact than if the analysis were carried out in the absence of the zero-mode waveguide.

  8. Excursions through KK modes

    SciTech Connect

    Furuuchi, Kazuyuki

    2016-07-07

    In this article we study Kaluza-Klein (KK) dimensional reduction of massive Abelian gauge theories with charged matter fields on a circle. Since local gauge transformations change position dependence of the charged fields, the decomposition of the charged matter fields into KK modes is gauge dependent. While whole KK mass spectrum is independent of the gauge choice, the mode number depends on the gauge. The masses of the KK modes also depend on the field value of the zero-mode of the extra dimensional component of the gauge field. In particular, one of the KK modes in the KK tower of each massless 5D charged field becomes massless at particular values of the extra-dimensional component of the gauge field. When the extra-dimensional component of the gauge field is identified with the inflaton, this structure leads to recursive cosmological particle productions.

  9. Accumulation boundaries: codimension-two accumulation of accumulations in phase diagrams of semiconductor lasers, electric circuits, atmospheric and chemical oscillators.

    PubMed

    Bonatto, Cristian; Gallas, Jason Alfredo Carlson

    2008-02-28

    We report high-resolution phase diagrams for several familiar dynamical systems described by sets of ordinary differential equations: semiconductor lasers; electric circuits; Lorenz-84 low-order atmospheric circulation model; and Rössler and chemical oscillators. All these systems contain chaotic phases with highly complicated and interesting accumulation boundaries, curves where networks of stable islands of regular oscillations with ever-increasing periodicities accumulate systematically. The experimental exploration of such codimension-two boundaries characterized by the presence of infinite accumulation of accumulations is feasible with existing technology for some of these systems.

  10. LANDSAT Range Resource Information System. [a user evaluation of green forage and rainfall accumulation maps

    NASA Technical Reports Server (NTRS)

    Boyd, W. E.; Harlan, J. C.

    1981-01-01

    A series of test products were developed from LANDSAT data sets for North Central Texas that paralleled the needs of ranchers, technical personnel, and the media. The products and evaluation questionnaires were mailed to approximately 150 ranchers who had reported an interest in evaluating the information systems. In addition to the rancher group, fourteen media people and a thirty-three member group in the agri business/technical community was also chosen to receive test products. The group responses are analyzed. Examples of the test products and associated questionnaires are included.

  11. Range Safety Systems

    NASA Technical Reports Server (NTRS)

    Schrock, Kenneth W.; Humphries, Ricky H. (Technical Monitor)

    2002-01-01

    The high kinetic and potential energy of a launch vehicle mandates there be a mechanism to minimize possible damage to provide adequate safety for the launch facilities, range, and, most importantly, the general public. The Range Safety System, sometimes called the Flight Termination System or Flight Safety System, provides the required level of safety. The Range Safety System section of the Avionics chapter will attempt to describe how adequate safety is provided, the system's design, operation, and it's interface with the rest of the launch vehicle.

  12. Transverse Effect due to Short-range Resistive Wall Wakefield

    SciTech Connect

    Juhao Wu; Alex Chao; Jean Delayen

    2007-06-18

    For accelerator designs with ultra short electron beams, beam dynamics study has to invoke the short-range wakefields. In this paper, we first obtain the short-range dipole mode resistive wall wakefield. Analytical approach is then developed to study the single bunch transverse beam dynamics due to this short-range resistive wall wake. The results are applied to the LCLS undulator.

  13. Transverse Effect Due to Short Range Resistive Wall Wakefield

    SciTech Connect

    Delayen, J.R.; Chao, Alexander Wu; Wu, J.; /SLAC

    2008-01-08

    For accelerator designs with ultra short electron beams, beam dynamics study has to invoke the short-range wakefields. In this paper, we first obtain the short-range dipole mode resistive wall wakefield. Analytical approach is then developed to study the single bunch transverse beam dynamics due to this short-range resistive wall wake. The results are applied to the LCLS undulator.

  14. Enhanced polyhydroxyalkanoates accumulation by Halomonas spp. in artificial biofilms of alginate beads.

    PubMed

    Berlanga, Mercedes; Miñana-Galbis, David; Domènech, Oscar; Guerrero, Ricardo

    2012-12-01

    Microbial mats are complex but stable, multi-layered and multi-functional biofilms, which are the most frequent bacterial formations in nature. The functional strategies and physiological versatility of the bacterial populations growing in microbial mats allow bacteria to resist changing conditions within their environment. One of these strategies is the accumulation of carbon- and energy-rich polymers that permit the recovery of metabolic activities when favorable conditions are restored. In the present study, we systematically screened microbial mats for bacteria able to accumulate large amounts of the ester carbon polymers polyhydroxyalkanoates (PHA). Several of these strains were isolated from Ebro Delta microbial mats and their ability to accumulate PHA up to 40-60% of their dry weight was confirmed. According to two identification approaches (16S rRNA and rpoD genes), these strains were identified as Halomonas alkaliphila (MAT-7, -13, -16), H. neptunia (MAT-17), and H. venusta (MAT-28). To determine the mode of growth yielding maximum PHA accumulation, these three different species were cultured in an artificial biofilm in which the cells were immobilized on alginate beads. PHA accumulation by cells that had detached from the biofilm was compared with that of their planktonic counterparts. Experiments in different culture media showed that PHA accumulation, measured as the relative fluorescence intensity after 48 h of incubation at 30 degrees C, was higher in immobilized than in planktonic cells, with the exception of cells growing in 5% NaCl, in which PHA accumulation was drastically lower in both. Therefore, for obtaining high PHA concentrations, the use of immobilized cells may be a good alternative to the PHA accumulation by bacteria growing in the classical, planktonic mode. From the ecological point of view, increased PHA accumulation in detached cells from biofilms would be a natural strategy to improve bacterial dispersion capacity and, consequently

  15. Preliminary error budget for an optical ranging system: Range, range rate, and differenced range observables

    NASA Technical Reports Server (NTRS)

    Folkner, W. M.; Finger, M. H.

    1990-01-01

    Future missions to the outer solar system or human exploration of Mars may use telemetry systems based on optical rather than radio transmitters. Pulsed laser transmission can be used to deliver telemetry rates of about 100 kbits/sec with an efficiency of several bits for each detected photon. Navigational observables that can be derived from timing pulsed laser signals are discussed. Error budgets are presented based on nominal ground stations and spacecraft-transceiver designs. Assuming a pulsed optical uplink signal, two-way range accuracy may approach the few centimeter level imposed by the troposphere uncertainty. Angular information can be achieved from differenced one-way range using two ground stations with the accuracy limited by the length of the available baseline and by clock synchronization and troposphere errors. A method of synchronizing the ground station clocks using optical ranging measurements is presented. This could allow differenced range accuracy to reach the few centimeter troposphere limit.

  16. No Accumulation of Transposable Elements in Asexual Arthropods.

    PubMed

    Bast, Jens; Schaefer, Ina; Schwander, Tanja; Maraun, Mark; Scheu, Stefan; Kraaijeveld, Ken

    2016-03-01

    Transposable elements (TEs) and other repetitive DNA can accumulate in the absence of recombination, a process contributing to the degeneration of Y-chromosomes and other nonrecombining genome portions. A similar accumulation of repetitive DNA is expected for asexually reproducing species, given their entire genome is effectively nonrecombining. We tested this expectation by comparing the whole-genome TE loads of five asexual arthropod lineages and their sexual relatives, including asexual and sexual lineages of crustaceans (Daphnia water fleas), insects (Leptopilina wasps), and mites (Oribatida). Surprisingly, there was no evidence for increased TE load in genomes of asexual as compared to sexual lineages, neither for all classes of repetitive elements combined nor for specific TE families. Our study therefore suggests that nonrecombining genomes do not accumulate TEs like nonrecombining genomic regions of sexual lineages. Even if a slight but undetected increase of TEs were caused by asexual reproduction, it appears to be negligible compared to variance between species caused by processes unrelated to reproductive mode. It remains to be determined if molecular mechanisms underlying genome regulation in asexuals hamper TE activity. Alternatively, the differences in TE dynamics between nonrecombining genomes in asexual lineages versus nonrecombining genome portions in sexual species might stem from selection for benign TEs in asexual lineages because of the lack of genetic conflict between TEs and their hosts and/or because asexual lineages may only arise from sexual ancestors with particularly low TE loads.

  17. High Precision Ranging and Range-Rate Measurements over Free-Space-Laser Communication Link

    NASA Technical Reports Server (NTRS)

    Yang, Guangning; Lu, Wei; Krainak, Michael; Sun, Xiaoli

    2016-01-01

    We present a high-precision ranging and range-rate measurement system via an optical-ranging or combined ranging-communication link. A complete bench-top optical communication system was built. It included a ground terminal and a space terminal. Ranging and range rate tests were conducted in two configurations. In the communication configuration with 622 data rate, we achieved a two-way range-rate error of 2 microns/s, or a modified Allan deviation of 9 x 10 (exp -15) with 10 second averaging time. Ranging and range-rate as a function of Bit Error Rate of the communication link is reported. They are not sensitive to the link error rate. In the single-frequency amplitude modulation mode, we report a two-way range rate error of 0.8 microns/s, or a modified Allan deviation of 2.6 x 10 (exp -15) with 10 second averaging time. We identified the major noise sources in the current system as the transmitter modulation injected noise and receiver electronics generated noise. A new improved system will be constructed to further improve the system performance for both operating modes.

  18. Subharmonic Fourier domain mode locking.

    PubMed

    Eigenwillig, Christoph M; Wieser, Wolfgang; Biedermann, Benjamin R; Huber, Robert

    2009-03-15

    We demonstrate a subharmonically Fourier domain mode-locked wavelength-swept laser source with a substantially reduced cavity fiber length. In contrast to a standard Fourier domain mode-locked configuration, light is recirculated repetitively in the delay line with the optical bandpass filter used as switch. The laser has a fundamental optical round trip frequency of 285 kHz and can be operated at integer fractions thereof (subharmonics). Sweep ranges up to 95 nm full width centred at 1317 nm are achieved at the 1/5th subharmonic. A maximum sensitivity of 116 dB and an axial resolution of 12 microm in air are measured at an average sweep power of 12 mW. A sensitivity roll-off of 11 dB over 4 mm and 25 dB over 10 mm is observed and optical coherence tomography imaging is demonstrated. Besides the advantage of a reduced fiber length, subharmonic Fourier domain mode locking (shFDML) enables simple scaling of the sweep speed by extracting light from the delay part of the resonator. A sweep rate of 570 kHz is achieved. Characteristic features of shFDML operation, such as power leakage during fly-back and cw breakthrough, are investigated.

  19. Evaluation of size segregation of elemental carbon emission in Europe: influence on atmospheric long-range transportation

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Cheng, Y. F.; Nordmann, S.; Birmili, W.; Denier van der Gon, H. A. C.; Ma, N.; Wolke, R.; Wehner, B.; Sun, J.; Spindler, G.; Mu, Q.; Pöschl, U.; Su, H.; Wiedensohler, A.

    2015-11-01

    Elemental Carbon (EC) has significant impact on human health and climate change. In order to evaluate the size segregation of EC emission and investigation of its influence on atmospheric transport processes in Europe, we used the fully coupled online Weather Research and Forecasting/Chemistry model (WRF-Chem) at a resolution of 2 km focusing on a region in Germany, in conjunction with a high-resolution EC emission inventory. The ground meteorology conditions, vertical structure and wind pattern were well reproduced by the model. The simulations of particle number/mass size distributions were evaluated by observations taken at the central European background site Melpitz. The fine mode aerosol was reasonably well simulated, but the coarse mode was substantially overestimated by the model. We found that it was mainly due to the nearby point source plume emitting a high amount of EC in the coarse mode. The comparisons between simulated EC and Multi-angle Absorption Photometers (MAAP) measurements at Melpitz, Leipzig-TROPOS and Bösel indicated that coarse mode EC (ECc) emission in the nearby point sources might be overestimated by a factor of 2-10. The emission fraction of EC in coarse mode was overestimated by about 10-30 % for Russian and 5-10 % for Eastern Europe (e.g.: Poland and Belarus), respectively. This overestimation in ECc emission fraction makes EC particles having less opportunity to accumulate in the atmosphere and participate to the long range transport, due to the shorter lifetime of coarse mode aerosol. The deposition concept model showed that the transported EC mass from Warsaw and Moskva to Melpitz may be reduced by 25-35 and 25-55 % respectively, due to the overestimation of ECc emission fraction. This may partly explain the underestimation of EC concentrations for Germany under eastern wind pattern in some other modelling research.

  20. Radar detection of surface oil accumulations

    NASA Technical Reports Server (NTRS)

    Estes, J. E.; Oneill, P.; Wilson, M.

    1980-01-01

    The United States Coast Guard is developing AIREYE, an all weather, day/night airborne surveillance system, for installation aboard future medium range surveillance aircraft. As part of this program, a series of controlled tests were conducted off southern California to evaluate the oil slick detection capabilities of two Motorola developed, side looking radars. The systems, a real aperture AN/APS-94D and a synthetic aperture coherent on receive (COR) were flown over the Santa Barbara Channel on May 19, 1976. Targets imaged during the coincident overflights included natural oil seepage, simulated oil spills, oil production platforms, piers, mooring buoys, commercial boats and barges at other targets. Based on an analysis of imagery from the coincident radar runs, COR provides better detection of natural and man made oil slicks, whereas the AN/APS-94D consistently exhibited higher surface target detection results. This and other tests have shown that active microwave systems have considerable potential for aiding in the detection and analysis of surface oil accumulations.

  1. Rabbit blastocysts accumulate (/sup 3/H)prostaglandins in vitro

    SciTech Connect

    Jones, M.A.; Harper, M.J.

    1984-08-01

    Rabbit blastocysts obtained on days 5, 6, and 6.8 of pregnancy were incubated in vitro in Tyrode's buffer with /sup 3/H-labeled prostaglandins (PGs). Accumulation of PGs was studied, using Whatman GF/F filters to separate bound and free ligands. The uptake and efflux of (/sup 3/H)PGs were studied as a function of PG type, incubation time, temperature, and effect of metabolic inhibitors as well as age and number of blastocysts. Blastocysts of the same age accumulated approximately the same amount of (/sup 3/H)PGE2 and (/sup 3/H)PGF2 alpha from their environment; however, there was no apparent saturation over a PG concentration range of 1-1000 nM. Both the uptake and efflux of PG were age dependent, with older blastocysts accumulating more PGs. Approximately 90% of the (/sup 3/H)PGs appear to be transported into the blastocoelic fluid, with little PG remaining in the blastomeres. PG accumulation was relatively insensitive to azide, ouabain, cyanide, or bromcresol green, but was affected by incubation at 0 C or the addition of indomethacin (10 micrograms/ml). No catabolism of the accumulated PGs was observed. The release of PGE2 in general did not differ from that of PGF2 alpha, except on day 6.8 of pregnancy when PGE2 was released more rapidly than on day 6. The authors conclude that rabbit blastocysts can accumulate PGs from their environment, which may imply a storage potential in the blastocyst and release before implantation.

  2. Limiter H-mode experiments on TFTR

    SciTech Connect

    Bush, C.E. ); Bretz, N.L.; Fredrickson, E.D.; McGuire, K.M.; Nazikian, R.; Park, H.K.; Schivell, J.; Taylor, G.; Bitter, M.; Budny, R.; Cohen, S.A.; Kilpatrick, S.J.; LeBlanc, B.; Manos, D.M.; Meade, D.; Paul, S.F.; Scott, S.D.; Stratton, B.C.; Synakowski, E.J.; Towner, H.H.; Wieland, R.M.; Arunasalam, V.; Bateman, G.; Bell, M.G.; Bell, R.; Boivin, R.; Cavallo, A.; Cheng, C.Z.; Chu, T.K.; Co

    1991-05-01

    Limiter H-modes with centrally peaked density profiles have been obtained in TFTR using a highly conditioned graphite limiter. The transition to these centrally peaked H-modes takes place from the supershot to the H-mode rather than the usual L- to H-mode transition observed on other tokamaks. Bidirectional beam heating is required to induce the transition. Density peaking factors, n{sub e}(0)/, greater than 2.3 are obtained and at the same time the H-mode characteristics are similar to those of limiter H-modes on other tokamaks, while the global confinement, {tau}{sub E}, can be >2.5 times L-mode scaling. The transport analysis of the data shows that transport in these H-modes is similar to that of supershots within the inner 0.6 m core of the plasma, but the stored electron energy (calculated using measured values of T{sub e} and n{sub e}) is higher for the H-mode at the plasma edge. Microwave scattering data for the edge plasma shows broad spectra at k = 5.5 cm{sup {minus}1} which begin at the drop in D{sub {alpha}} radiation and are strongly shifted in the electron diamagnetic drift direction. At the same time, beam emission spectroscopy (BES) shows a coherent mode near the boundary which propagates in the ion direction with m = 15--20 at 20--30 kHz. During the ELM event these apparent rotations cease and Mirnov fluctuations in the frequency range of 50--500 kHz increase in intensity. 16 refs., 8 figs.

  3. Ischaemic accumulation of succinate controls reperfusion injury through mitochondrial ROS

    PubMed Central

    Gaude, Edoardo; Aksentijević, Dunja; Sundier, Stephanie Y.; Robb, Ellen L.; Logan, Angela; Nadtochiy, Sergiy M.; Ord, Emily N. J.; Smith, Anthony C.; Eyassu, Filmon; Shirley, Rachel; Hu, Chou-Hui; Dare, Anna J.; James, Andrew M.; Rogatti, Sebastian; Hartley, Richard C.; Eaton, Simon; Costa, Ana S.H.; Brookes, Paul S.; Davidson, Sean M.; Duchen, Michael R.; Saeb-Parsy, Kourosh; Shattock, Michael J.; Robinson, Alan J.; Work, Lorraine M.; Frezza, Christian; Krieg, Thomas; Murphy, Michael P.

    2014-01-01

    Ischaemia-reperfusion (IR) injury occurs when blood supply to an organ is disrupted and then restored, and underlies many disorders, notably heart attack and stroke. While reperfusion of ischaemic tissue is essential for survival, it also initiates oxidative damage, cell death, and aberrant immune responses through generation of mitochondrial reactive oxygen species (ROS)1-5. Although mitochondrial ROS production in IR is established, it has generally been considered a non-specific response to reperfusion1,3. Here, we developed a comparative in vivo metabolomic analysis and unexpectedly identified widely conserved metabolic pathways responsible for mitochondrial ROS production during IR. We showed that selective accumulation of the citric acid cycle (CAC) intermediate succinate is a universal metabolic signature of ischaemia in a range of tissues and is responsible for mitochondrial ROS production during reperfusion. Ischaemic succinate accumulation arises from reversal of succinate dehydrogenase (SDH), which in turn is driven by fumarate overflow from purine nucleotide breakdown and partial reversal of the malate/aspartate shuttle. Upon reperfusion, the accumulated succinate is rapidly re-oxidised by SDH, driving extensive ROS generation by reverse electron transport (RET) at mitochondrial complex I. Decreasing ischaemic succinate accumulation by pharmacological inhibition is sufficient to ameliorate in vivo IR injury in murine models of heart attack and stroke. Thus, we have identified a conserved metabolic response of tissues to ischaemia and reperfusion that unifies many hitherto unconnected aspects of IR injury. Furthermore, these findings reveal a novel pathway for metabolic control of ROS production in vivo, while demonstrating that inhibition of ischaemic succinate accumulation and its oxidation upon subsequent reperfusion is a potential therapeutic target to decrease IR injury in a range of pathologies. PMID:25383517

  4. Assessment of gas accumulation and retention -- Tank 241-SY-101

    SciTech Connect

    Alleman, R.T.; Burke, T.M.; Reynolds, D.A.; Simpson, D.E.

    1993-03-01

    An approximate analysis has been carried out to assess and estimate the maximum quantity of gas that is likely to be accumulated within waste tank 241-SY-101, and the maximum quantity which is likely to be retained after gas release events (GRE). According to the phenomenological models used for this assessment, based on interpretation of current and recent operational data, the estimated gas generation rate in the tank is approximately 4 m{sup 3}/day (147 ft{sup 3}/day). About half of this gas is released as it is generated, which is (essentially) continuously. The remainder is accumulated within the slurry layer of settled solids at the bottom of the tank, and released episodically in GREs, known as ``burps,`` that are induced by unstable buoyant conditions which develop when sufficient gas accumulates in the slurry. Calculations based on gas volumes to cause neutral buoyancy in the slurry predict the following: the maximum gas accumulation (at 1 atm pressure) that can occur without triggering a GRE is in the range of 606 to 1,039 m{sup 3} (21,400 to 36,700 ft{sup 3}); and the maximum gas retention immediately after a GRE is equal to the maximum accumulation minus the gas released in the GRE. GREs do not necessarily involve all of the slurry. In the largest GREs, which are assumed to involve all of the slurry, the minimum gas release (at 1 atm pressure) is calculated to be in the range of 193 to 328 m{sup 3} (6,800 to 11,600 ft{sup 3}). The corresponding maximum gas retention would be 413 to 711 m{sup 3} (14,600 to 25,100 ft{sup 3}).

  5. Critical configurations (determinantal loci) for range and range difference satellite networks

    NASA Technical Reports Server (NTRS)

    Tsimis, E.

    1973-01-01

    The observational modes of Geometric Satellite Geodesy are discussed. The geometrical analysis of the problem yielded a regression model for the adjustment of the observations along with a suitable and convenient metric for the least-squares criterion. The determinantal loci (critical configurations) for range networks are analyzed. An attempt is made to apply elements of the theory of variants for this purpose. The use of continuously measured range differences for loci determination is proposed.

  6. Laser Ranging Simulation Program

    NASA Technical Reports Server (NTRS)

    Piazolla, Sabino; Hemmati, Hamid; Tratt, David

    2003-01-01

    Laser Ranging Simulation Program (LRSP) is a computer program that predicts selected aspects of the performances of a laser altimeter or other laser ranging or remote-sensing systems and is especially applicable to a laser-based system used to map terrain from a distance of several kilometers. Designed to run in a more recent version (5 or higher) of the MATLAB programming language, LRSP exploits the numerical and graphical capabilities of MATLAB. LRSP generates a graphical user interface that includes a pop-up menu that prompts the user for the input of data that determine the performance of a laser ranging system. Examples of input data include duration and energy of the laser pulse, the laser wavelength, the width of the laser beam, and several parameters that characterize the transmitting and receiving optics, the receiving electronic circuitry, and the optical properties of the atmosphere and the terrain. When the input data have been entered, LRSP computes the signal-to-noise ratio as a function of range, signal and noise currents, and ranging and pointing errors.

  7. Mode II fatigue crack propagation.

    NASA Technical Reports Server (NTRS)

    Roberts, R.; Kibler, J. J.

    1971-01-01

    Fatigue crack propagation rates were obtained for 2024-T3 bare aluminum plates subjected to in-plane, mode I, extensional loads and transverse, mode II, bending loads. These results were compared to the results of Iida and Kobayashi for in-plane mode I-mode II extensional loads. The engineering significance of mode I-mode II fatigue crack growth is considered in view of the present results. A fatigue crack growth equation for handling mode I-mode II fatigue crack growth rates from existing mode I data is also discussed.

  8. Holographic thermalization with initial long range correlation

    DOE PAGES

    Lin, Shu

    2016-01-19

    Here, we studied the evolution of the Wightman correlator in a thermalizing state modeled by AdS3-Vaidya background. A prescription was given for calculating the Wightman correlator in coordinate space without using any approximation. For equal-time correlator , we obtained an enhancement factor v2 due to long range correlation present in the initial state. This was missed by previous studies based on geodesic approximation. Moreover, we found that the long range correlation in initial state does not lead to significant modification to thermalization time as compared to known results with generic initial state. We also studied the spatially integrated Wightman correlatormore » and showed evidence on the distinction between long distance and small momentum physics for an out-of-equilibrium state. We also calculated the radiation spectrum of particles weakly coupled to O and found that lower frequency mode approaches thermal spectrum faster than high frequency mode.« less

  9. Supersymmetric mode converters

    NASA Astrophysics Data System (ADS)

    Heinrich, Matthias; Miri, Mohammad-Ali; Stützer, Simon; Nolte, Stefan; Szameit, Alexander; Christodoulides, Demetrios N.

    2015-08-01

    In recent years, the ever-increasing demand for high-capacity transmission systems has driven remarkable advances in technologies that encode information on an optical signal. Mode-division multiplexing makes use of individual modes supported by an optical waveguide as mutually orthogonal channels. The key requirement in this approach is the capability to selectively populate and extract specific modes. Optical supersymmetry (SUSY) has recently been proposed as a particularly elegant way to resolve this design challenge in a manner that is inherently scalable, and at the same time maintains compatibility with existing multiplexing strategies. Supersymmetric partners of multimode waveguides are characterized by the fact that they share all of their effective indices with the original waveguide. The crucial exception is the fundamental mode, which is absent from the spectrum of the partner waveguide. Here, we demonstrate experimentally how this global phase-matching property can be exploited for efficient mode conversion. Multimode structures and their superpartners are experimentally realized in coupled networks of femtosecond laser-written waveguides, and the corresponding light dynamics are directly observed by means of fluorescence microscopy. We show that SUSY transformations can readily facilitate the removal of the fundamental mode from multimode optical structures. In turn, hierarchical sequences of such SUSY partners naturally implement the conversion between modes of adjacent order. Our experiments illustrate just one of the many possibilities of how SUSY may serve as a building block for integrated mode-division multiplexing arrangements. Supersymmetric notions may enrich and expand integrated photonics by versatile optical components and desirable, yet previously unattainable, functionalities.

  10. Satellite Laser Ranging operations

    NASA Technical Reports Server (NTRS)

    Pearlman, Michael R.

    1994-01-01

    Satellite Laser Ranging (SLR) is currently providing precision orbit determination for measurements of: 1) Ocean surface topography from satellite borne radar altimetry, 2) Spatial and temporal variations of the gravity field, 3) Earth and ocean tides, 4) Plate tectonic and regional deformation, 5) Post-glacial uplift and subsidence, 6) Variations in the Earth's center-of-mass, and 7) Variations in Earth rotation. SLR also supports specialized programs in time transfer and classical geodetic positioning, and will soon provide precision ranging to support experiments in relativity.

  11. Broad host range plasmids.

    PubMed

    Jain, Aayushi; Srivastava, Preeti

    2013-11-01

    Plasmids are and will remain important cloning vehicles for biotechnology. They have also been associated with the spread of a number of diseases and therefore are a subject of environmental concern. With the advent of sequencing technologies, the database of plasmids is increasing. It will be of immense importance to identify the various bacterial hosts in which the plasmid can replicate. The present review article describes the features that confer broad host range to the plasmids, the molecular basis of plasmid host range evolution, and applications in recombinant DNA technology and environment.

  12. Western Aeronautical Test Range

    NASA Technical Reports Server (NTRS)

    Sakahara, Robert D.

    2008-01-01

    This viewgraph presentation reviews the work of the Western Aeronautical Test Range (WATR). NASA's Western Aeronautical Test Range is a network of facilities used to support aeronautical research, science missions, exploration system concepts, and space operations. The WATR resides at NASA's Dryden Flight Research Center located at Edwards Air Force Base, California. The WATR is a part of NASA's Corporate Management of Aeronautical Facilities and funded by the Strategic Capability Asset Program (SCAP). Maps show the general location of the WATR area that is used for aeronautical testing and evaluation. The products, services and facilities of WATR are discussed,

  13. Entanglement generation between two atoms via surface modes

    SciTech Connect

    Xu Jingping; Yang Yaping; Al-Amri, M.; Zhu Shiyao; Zubairy, M. Suhail

    2011-09-15

    We discuss the coupling of two identical atoms, separated by a metal or metamaterial slab, through surface modes. We show that the coupling through the surface modes can induce entanglement. We discuss how to control the coupling for the metal or metamaterial slab by adjusting the symmetrical and antisymmetrical property of the surface modes. We analyze the dispersion relation of the surface modes and study the parameter ranges that support the surface modes with the same properties. Our results have potential applications in quantum communication and quantum computation.

  14. Effect of Trapped Energetic Particles on the Resistive Wall Mode

    SciTech Connect

    Hao, G. Z.; Wang, A. K.; Qiu, X. M.; Liu, Y. Q.

    2011-07-01

    A stability analysis for the resistive wall mode is studied in the presence of trapped energetic particles (EPs). When the EPs' beta exceeds a critical value, a fishbonelike bursting mode (FLM) with an external kink eigenstructure can exist. This offers the first analytic interpretation of the experimental observations [Phys. Rev. Lett. 103, 045001 (2009)]. The mode-particle resonances for the FLM and the q=1 fishbone occur in different regimes of the precession frequency of EPs. In certain ranges of the plasma rotation speed and the EPs' beta, a mode conversion can occur between the resistive wall mode and FLM.

  15. Mode identification of whistler mode, Z-mode, and Langmuir/Upper Hybrid mode waves observed in an auroral sounding rocket experiment

    NASA Astrophysics Data System (ADS)

    Colpitts, C. A.; Labelle, J.

    2008-04-01

    The SIERRA (Sounding of the Ion Energization Region - Resolving Ambiguities) rocket was launched to 735 km over an active auroral substorm from Poker Flat, Alaska, on 14 January 2002. A wealth of wave modes at frequencies from below 100 kHz to above 2000 kHz were detected with a dipole electric field antenna that was alternately parallel and perpendicular to Earth's magnetic field. At least two types of whistler mode waves were detected: unstructured broadband whistler waves commonly referred to as auroral hiss occurring at frequencies from <100 kHz up to 1000 kHz, and structured narrowband features in the whistler mode at frequencies of 100 kHz to 600 kHz (Samara and LaBelle, 2006a). Other waves detected in the frequency range 1200 to 2000 kHz were interpreted as Langmuir-upper hybrid waves and Z-mode waves. For the unstructured whistler mode waves, comparison of the observed spin dependence of the wave electric fields with Monte Carlo simulations of the expected spin dependence for various polarizations suggests that these waves propagate on or near the resonance cone, which is consistent with previous measurements. Similar analyses of the presumed Langmuir and Z-mode waves show their electric fields are preferentially parallel and perpendicular to the ambient magnetic field, respectively. These characteristics, together with the relation of the wave frequencies to the Z cutoff frequency, serve to confirm the mode identification of these waves.

  16. Observation of pedestal turbulence in edge localized mode-free H-mode on experimental advanced superconducting tokamak

    SciTech Connect

    Han, X. Zhang, T.; Zhang, S. B.; Wang, Y. M.; Shi, T. H.; Liu, Z. X.; Kong, D. F.; Qu, H.; Gao, X.

    2014-10-15

    Two different pedestal turbulence structures have been observed in edge localized mode-free phase of H-mode heated by lower hybrid wave and RF wave in ion cyclotron range of frequencies (ICRF) on experimental advanced superconducting tokamak. When the fraction of ICRF power P{sub ICRF}/P{sub total} exceeds 0.7, coherent mode is observed. The mode is identified as an electromagnetic mode, rotating in electron diamagnetic direction with a frequency around 50 kHz and toroidal mode number n = −3. Whereas when P{sub ICRF}/P{sub total} is less than 0.7, harmonic mode with frequency f = 40–300 kHz appears instead. The characteristics of these two modes are demonstrated preliminarily. The threshold value of heating power and also the plasma parameters are distinct.

  17. 46 CFR 58.30-25 - Accumulators.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... RELATED SYSTEMS Fluid Power and Control Systems § 58.30-25 Accumulators. (a) An accumulator is an unfired pressure vessel in which energy is stored under high pressure in the form of a gas or a gas and hydraulic... result in contamination of the hydraulic fluid and loss of gas through absorption. (c) Each...

  18. 46 CFR 58.30-25 - Accumulators.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... RELATED SYSTEMS Fluid Power and Control Systems § 58.30-25 Accumulators. (a) An accumulator is an unfired pressure vessel in which energy is stored under high pressure in the form of a gas or a gas and hydraulic... result in contamination of the hydraulic fluid and loss of gas through absorption. (c) Each...

  19. 40 CFR 262.34 - Accumulation time.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) STANDARDS APPLICABLE TO GENERATORS OF HAZARDOUS WASTE Pre-Transport Requirements § 262.34 Accumulation time. (a) Except as provided in paragraphs (d), (e), and (f) of this section, a generator may accumulate...: (1) The waste is placed: (i) In containers and the generator complies with the...

  20. 40 CFR 262.34 - Accumulation time.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) STANDARDS APPLICABLE TO GENERATORS OF HAZARDOUS WASTE Pre-Transport Requirements § 262.34 Accumulation time. (a) Except as provided in paragraphs (d), (e), and (f) of this section, a generator may accumulate...: (1) The waste is placed: (i) In containers and the generator complies with the...

  1. 40 CFR 262.34 - Accumulation time.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) STANDARDS APPLICABLE TO GENERATORS OF HAZARDOUS WASTE Pre-Transport Requirements § 262.34 Accumulation time. (a) Except as provided in paragraphs (d), (e), and (f) of this section, a generator may accumulate...: (1) The waste is placed: (i) In containers and the generator complies with the...

  2. 40 CFR 262.34 - Accumulation time.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) STANDARDS APPLICABLE TO GENERATORS OF HAZARDOUS WASTE Pre-Transport Requirements § 262.34 Accumulation time. (a) Except as provided in paragraphs (d), (e), and (f) of this section, a generator may accumulate...: (1) The waste is placed: (i) In containers and the generator complies with the...

  3. 40 CFR 262.34 - Accumulation time.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) STANDARDS APPLICABLE TO GENERATORS OF HAZARDOUS WASTE Pre-Transport Requirements § 262.34 Accumulation time. (a) Except as provided in paragraphs (d), (e), and (f) of this section, a generator may accumulate...: (1) The waste is placed: (i) In containers and the generator complies with the...

  4. 19 CFR 10.2017 - Accumulation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 1 2014-04-01 2014-04-01 false Accumulation. 10.2017 Section 10.2017 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY... Rules of Origin § 10.2017 Accumulation. (a) Originating materials from the territory of a Party that...

  5. Accumulation and hyperaccumulation of copper in plants

    NASA Astrophysics Data System (ADS)

    Adam, V.; Trnkova, L.; Huska, D.; Babula, P.; Kizek, R.

    2009-04-01

    Copper is natural component of our environment. Flow of copper(II) ions in the environment depends on solubility of compounds containing this metal. Mobile ion coming from soil and rocks due to volcanic activity, rains and others are then distributed to water. Bio-availability of copper is substantially lower than its concentration in the aquatic environment. Copper present in the water reacts with other compounds and creates a complex, not available for organisms. The availability of copper varies depending on the environment, but moving around within the range from 5 to 25 % of total copper. Thus copper is stored in the sediments and the rest is transported to the seas and oceans. It is common knowledge that copper is essential element for most living organisms. For this reason this element is actively accumulated in the tissues. The total quantity of copper in soil ranges from 2 to 250 mg / kg, the average concentration is 30 mg / kg. Certain activities related to agriculture (the use of fungicides), possibly with the metallurgical industry and mining, tend to increase the total quantity of copper in the soil. This amount of copper in the soil is a problem particularly for agricultural production of food. The lack of copper causes a decrease in revenue and reduction in quality of production. In Europe, shows the low level of copper in total 18 million hectares of farmland. To remedy this adverse situation is the increasing use of copper fertilizers in agricultural soils. It is known that copper compounds are used in plant protection against various illnesses and pests. Mining of minerals is for the development of human society a key economic activity. An important site where the copper is mined in the Slovakia is nearby Smolníka. Due to long time mining in his area (more than 700 years) there are places with extremely high concentrations of various metals including copper. Besides copper, there are also detected iron, zinc and arsenic. Various plant species

  6. Agriculture, forestry, range resources

    NASA Technical Reports Server (NTRS)

    Crea, W. J.

    1974-01-01

    In the area of crop specie identification, it has been found that temporal data analysis, preliminary stratification, and unequal probability analysis were several of the factors that contributed to high identification accuracies. Single data set accuracies on fields of greater than 80,000 sq m (20 acres) are in the 70- to 90-percent range; however, with the use of temporal data, accuracies of 95 percent have been reported. Identification accuracy drops off significantly on areas of less than 80,000 sq m (20 acres) as does measurement accuracy. Forest stratification into coniferous and deciduous areas has been accomplished to a 90- to 95-percent accuracy level. Using multistage sampling techniques, the timber volume of a national forest district has been estimated to a confidence level and standard deviation acceptable to the Forest Service at a very favorable cost-benefit time ratio. Range specie/plant community vegetation mapping has been accomplished at various levels of success (69- to 90-percent accuracy). However, several investigators have obtained encouraging initial results in range biomass (forage production) estimation and range readiness predictions. Soil association map correction and soil association mapping in new area appear to have been proven feasible on large areas; however, testing in a complex soil area should be undertaken.

  7. Agriculture, forestry, range resources

    NASA Technical Reports Server (NTRS)

    Macdonald, R. B.

    1974-01-01

    The necessary elements to perform global inventories of agriculture, forestry, and range resources are being brought together through the use of satellites, sensors, computers, mathematics, and phenomenology. Results of ERTS-1 applications in these areas, as well as soil mapping, are described.

  8. Front Range Branch Officers

    NASA Astrophysics Data System (ADS)

    The Front Range Branch of AGU has installed officers for 1990: Ray Noble, National Center for Atmospheric Research, chair; Sherry Oaks, U.S. Geological Survey, chair-elect; Howard Garcia, NOAA, treasurer; Catharine Skokan, Colorado School of Mines, secretary. JoAnn Joselyn of NOAA is past chair. Members at large are Wallace Campbell, NOAA; William Neff, USGS; and Stephen Schneider, NCAR.

  9. Nonscanning confocal ranging system

    NASA Astrophysics Data System (ADS)

    Sun, P. C.; Arons, E.

    1995-03-01

    We demonstrate a nonscanning confocal ranging system based on spatially incoherent interferometry. Such a system has significant advantages over the conventional confocal imaging system and other interferometric systems. We develop the theory in terms of coherence cells and demonstrate the equivalence of our method to the conventional confocal methods. Experimental results are also provided.

  10. Electric vehicles: Driving range

    NASA Astrophysics Data System (ADS)

    Kempton, Willett

    2016-09-01

    For uptake of electric vehicles to increase, consumers' driving-range needs must be fulfilled. Analysis of the driving patterns of personal vehicles in the US now shows that today's electric vehicles can meet all travel needs on almost 90% of days from a single overnight charge.

  11. RADIO RANGING DEVICE

    DOEpatents

    Bogle, R.W.

    1960-11-22

    A description is given of a super-regenerative oscillator ranging device provided with radiating and receiving means and being capable of indicating the occurrence of that distance between itself and a reflecting object which so phases the received echo of energy of a preceding emitted oscillation that the intervals between oscillations become uniform.

  12. Long Range Plan.

    ERIC Educational Resources Information Center

    Jefferson Coll., Hillsboro, MO.

    This document presents Jefferson College's "Long Range Plan," which is intended to provide the College's governing board, administration, and faculty and staff with a task-oriented blueprint for maximizing the delivery of higher education services to students and the community in a predictable, programmatic, and fiscally sound manner.…

  13. STDN ranging equipment

    NASA Technical Reports Server (NTRS)

    Jones, C. E.

    1975-01-01

    Final results of the Spaceflight Tracking and Data Network (STDN) Ranging Equipment program are summarized. Basic design concepts and final design approaches are described. Theoretical analyses which define requirements and support the design approaches are presented. Design verification criteria are delineated and verification test results are specified.

  14. Agriculture, forest, and range

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The findings and recommendations of the panel for developing a satellite remote-sensing global information system in the next decade are reported. User requirements were identified in five categories: (1) cultivated crops, (2) land resources, (3)water resources, (4)forest management, and (5) range management. The benefits from the applications of satellite data are discussed.

  15. Fact Sheet: Range Complex

    NASA Technical Reports Server (NTRS)

    Cornelson, C.; Fretter, E.

    2004-01-01

    NASA Ames has a long tradition in leadership with the use of ballistic ranges and shock tubes for the purpose of studying the physics and phenomena associated with hypervelocity flight. Cutting-edge areas of research run the gamut from aerodynamics, to impact physics, to flow-field structure and chemistry. This legacy of testing began in the NACA era of the 1940's with the Supersonic Free Flight Tunnel, and evolved dramatically up through the late 1950s with the pioneering work in the Ames Hypersonic Ballistic Range. The tradition continued in the mid-60s with the commissioning of the three newest facilities: the Ames Vertical Gun Range (AVGR) in 1964, the Hypervelocity Free Flight Facility (HFFF) in 1965 and the Electric Arc Shock Tube (EAST) in 1966. Today the Range Complex continues to provide unique and critical testing in support of the Nation's programs for planetary geology and geophysics; exobiology; solar system origins; earth atmospheric entry, planetary entry, and aerobraking vehicles; and various configurations for supersonic and hypersonic aircraft.

  16. Fault core and damage zone fracture attributes vary along strike owing to interaction of fracture growth, quartz accumulation, and differing sandstone composition

    NASA Astrophysics Data System (ADS)

    Laubach, S. E.; Eichhubl, P.; Hargrove, P.; Ellis, M. A.; Hooker, J. N.

    2014-11-01

    Small, meter-to decimeter-displacement oblique-slip faults cut latest Precambrian lithic arkose to feldspathic litharenite and Cambrian quartz arenite sandstones in NW Scotland. Despite common slip and thermal histories during faulting, the two sandstone units have different fault-core and damage-zone attributes, including fracture length and aperture distributions, and location of quartz deposits. Fault cores are narrow (less than 1 m), low-porosity cataclasite in lithic arkose/feldspathic litharenites. Damage zone-parallel opening-mode fractures are long (meters or more) with narrow ranges of lengths and apertures, are mostly isolated, have sparse quartz cement, and are open. In contrast, quartz arenites, despite abundant quartz cement, have fault cores that contain porous breccia and dense, striated slip zones. Damage-zone fractures have lengths ranging from meters to centimeters or less, but with distributions skewed to short fractures, and have power-law aperture distributions. Owing to extensive quartz cement, they tend to be sealed. These attributes reflect inhibited authigenic quartz accumulation on feldspar and lithic grains, which are unfavorable precipitation substrates, and favored accumulation on detrital quartz. In quartz breccia, macropores >0.04 mm wide persist where surrounded by slow-growing euhedral quartz. Differences in quartz occurrence and size distributions are compatible with the hypothesis that cement deposits modify the probability of fracture reactivation. Existing fractures readily reactivate in focused growth where quartz accumulation is low and porosity high. Only some existing, partly cemented fractures reactivate and some deformation is manifest in new fracture formation in partitioned growth where quartz accumulation is high. Consequences include along-strike differences in permeability and locus of fluid flow between cores and damage zones and fault strength.

  17. Experimental Investigation and Analysis of an Annular Pogo Accumulator

    NASA Technical Reports Server (NTRS)

    Peugeot, John; Schwarz, Jordan; Yang, H. Q.; Zoladz, Tom

    2011-01-01

    An experimental investigation was conducted on a scaled annular pogo accumulator for the Ares I Upper Stage. The test article was representative of the LO2 feedline and preliminary accumulator design, and included multiple designs of a perforated ring connecting the accumulator to the core feedline flow. The system was pulse tested in water over a range of pulse frequency and flow rates. Time dependent measurements of pressure at various locations in the test article were used to extract system compliance, inertance, and resistance. Preliminary results indicated a significant deviation from standard orifice flow theory and suggest a strong dependence on feedline average velocity. In addition, several CFD analyses were conducted to investigate the details of the time variant flow field. Both two-dimensional and three-dimensional simulations were performed with time varying boundary conditions used to represent system pulsing. The CFD results compared well with the sub-scale results and demonstrated the influence of feedline average velocity on the flow into and out of the accumulator. This paper presents updated results of the investigation including a parametric design space for determining resistance characteristics. Using the updated experimental results a new scaling relationship has been defined for shear flow over a cavity. A comparison of sub-scale and full scale CFD simulations provided early verification of the scaling of the fluid flowfield and resistance characteristics.

  18. Accumulation of heavy metals in the earthworm Eisenia foetida

    SciTech Connect

    Hartenstein, R.; Neuhauser, E.F.; Collier, J.

    1980-01-01

    Conversion of waste-activated sludge into egesta by the earthworm Eisenia foetida resulted in neither an increase nor decrease of 0.1 N HCl-extractable cadmium, copper, nickel, lead, or zinc. The addition of 2500 ppM copper as copper sulfate to activated sludge caused 100% mortality whthin 1 week, though feeding upon nonamended activated sludges with up to 1500 ppM copper over several months was innocuous. Amendment of sludge with 10, 50, and 100 ppM Cd as CdSO/sub 4/ resulted in 3.90-, 2.04-, and 1.44-fold concentrations in the earthworm over the quantities present in the sludge, with a range of 118 to 170 ppM being found on exposure to the highest level for periods of 1 to 5 weeks at 25/sup 0/C. In field trials with nonamended sludge, however, containing 12 to 27 ppM Cd, biweekly sampling for 28 weeks revealed accumulations in E. foetida ranging from 8 to 46 ppM; control earthworms not exposed to culture media with easily measurable Cd levels contained 0.3 to 2 ppM Cd. Upwards to about 50 ppM Ni, 325 ppM Pb, and 250 ppM Zn accumulated from sludges amended with ionic soluble forms of these metals. In the field, where these metals ranged from 2 to 46, 1 to 53, and 68 to 210 ppM, respectively, an upper concentration of about 50 ppM Ni, 55 ppM Pb, and 250 ppM Zn were found in the earthworm. Distinctions were made between accumulable and concentratable and a discussion is provided to show that each of the most problematic heavy metals, Cd, Zn, Ni, Pb, and Cu, may accumulate or concentrate in the earthworm.

  19. Hardware test program for evaluation of baseline range-range rate sensor concept

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The baseline range/range rate sensor concept was evaluated. The Interrupted CW (ICW) mode of operation continued with emphasis on establishing the sensitivity of the video portion of the receiver was 7 dB less than the theoretical value. This departs from test results of previous implementations in which achieved sensitivity was within 1.5 to 2 dB of the theoretical value. Several potential causes of this discrepancy in performance were identified and are scheduled for further investigation. Results indicate that a cost savings in both per unit and program costs are realizable by eliminating one of the modes of operation. An acquisition (total program) cost savings of approximately 10% is projected by eliminating the CW mode of operation. The modified R/R sensor would operate in the ICW mode only and would provide coverage from initial acquisition at 12 nmi to within a few hundred feet of the OMV. If the ICW mode only were selected, then an accompanying sensor would be required to provide coverage from a few hundred feet to docking.

  20. Verification of International Space Station Component Leak Rates by Helium Accumulation Method

    NASA Technical Reports Server (NTRS)

    Underwood, Steve D.; Smith, Sherry L.

    2003-01-01

    Discovery of leakage on several International Space Station U.S. Laboratory Module ammonia system quick disconnects (QDs) led to the need for a process to quantify total leakage without removing the QDs from the system. An innovative solution was proposed allowing quantitative leak rate measurement at ambient external pressure without QD removal. The method utilizes a helium mass spectrometer configured in the detector probe mode to determine helium leak rates inside a containment hood installed on the test component. The method was validated through extensive developmental testing. Test results showed the method was viable, accurate and repeatable for a wide range of leak rates. The accumulation method has been accepted by NASA and is currently being used by Boeing Huntsville, Boeing Kennedy Space Center and Boeing Johnson Space Center to test welds and valves and will be used by Alenia to test the Cupola. The method has been used in place of more expensive vacuum chamber testing which requires removing the test component from the system.

  1. Range expansion of mutualists

    NASA Astrophysics Data System (ADS)

    Muller, Melanie J. I.; Korolev, Kirill S.; Murray, Andrew W.; Nelson, David R.

    2012-02-01

    The expansion of a species into new territory is often strongly influenced by the presence of other species. This effect is particularly striking for the case of mutualistic species that enhance each other's proliferation. Examples range from major events in evolutionary history, such as the spread and diversification of flowering plants due to their mutualism with pollen-dispersing insects, to modern examples like the surface colonisation of multi-species microbial biofilms. Here, we investigate the spread of cross-feeding strains of the budding yeast Saccharomyces cerevisiae on an agar surface as a model system for expanding mutualists. Depending on the degree of mutualism, the two strains form distinctive spatial patterns during their range expansion. This change in spatial patterns can be understood as a phase transition within a stepping stone model generalized to two mutualistic species.

  2. Long Range Materials Research

    DTIC Science & Technology

    1974-12-31

    India, also called bulat steels, are known to have high carbon contents, commonly 1.5 to 2.0% carbon. The high quality of these steels is well...gamma-cementite range, essentially all of the cementite is converted to the spheroidized form. However, during transformation...plus additional cementite In non-spheroldlzed form, typically l>iates. As set forth above, It is Important that essentially

  3. Light beam range finder

    DOEpatents

    McEwan, Thomas E.

    1998-01-01

    A "laser tape measure" for measuring distance which includes a transmitter such as a laser diode which transmits a sequence of electromagnetic pulses in response to a transmit timing signal. A receiver samples reflections from objects within the field of the sequence of visible electromagnetic pulses with controlled timing, in response to a receive timing signal. The receiver generates a sample signal in response to the samples which indicates distance to the object causing the reflections. The timing circuit supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver. The receive timing signal causes the receiver to sample the reflection such that the time between transmission of pulses in the sequence in sampling by the receiver sweeps over a range of delays. The transmit timing signal causes the transmitter to transmit the sequence of electromagnetic pulses at a pulse repetition rate, and the received timing signal sweeps over the range of delays in a sweep cycle such that reflections are sampled at the pulse repetition rate and with different delays in the range of delays, such that the sample signal represents received reflections in equivalent time. The receiver according to one aspect of the invention includes an avalanche photodiode and a sampling gate coupled to the photodiode which is responsive to the received timing signal. The transmitter includes a laser diode which supplies a sequence of visible electromagnetic pulses. A bright spot projected on to the target clearly indicates the point that is being measured, and the user can read the range to that point with precision of better than 0.1%.

  4. Light beam range finder

    DOEpatents

    McEwan, T.E.

    1998-06-16

    A ``laser tape measure`` for measuring distance is disclosed which includes a transmitter such as a laser diode which transmits a sequence of electromagnetic pulses in response to a transmit timing signal. A receiver samples reflections from objects within the field of the sequence of visible electromagnetic pulses with controlled timing, in response to a receive timing signal. The receiver generates a sample signal in response to the samples which indicates distance to the object causing the reflections. The timing circuit supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver. The receive timing signal causes the receiver to sample the reflection such that the time between transmission of pulses in the sequence in sampling by the receiver sweeps over a range of delays. The transmit timing signal causes the transmitter to transmit the sequence of electromagnetic pulses at a pulse repetition rate, and the received timing signal sweeps over the range of delays in a sweep cycle such that reflections are sampled at the pulse repetition rate and with different delays in the range of delays, such that the sample signal represents received reflections in equivalent time. The receiver according to one aspect of the invention includes an avalanche photodiode and a sampling gate coupled to the photodiode which is responsive to the received timing signal. The transmitter includes a laser diode which supplies a sequence of visible electromagnetic pulses. A bright spot projected on to the target clearly indicates the point that is being measured, and the user can read the range to that point with precision of better than 0.1%. 7 figs.

  5. Long range chromatin organization

    PubMed Central

    Acuña, Luciana I Gómez; Kornblihtt, Alberto R

    2014-01-01

    Splicing is a predominantly co-transcriptional process that has been shown to be tightly coupled to transcription. Chromatin structure is a key factor that mediates this functional coupling. In light of recent evidence that shows the importance of higher order chromatin organization in the coordination and regulation of gene expression, we discuss here the possible roles of long-range chromatin organization in splicing and alternative splicing regulation. PMID:25764333

  6. Photometric Passive Range Sensor

    NASA Astrophysics Data System (ADS)

    Argueta-Diaz, Victor; García-Valenzuela, Augusto

    2008-04-01

    In this paper we present a passive optical ranging method that consists of taking several photometric measurements from the light radiated by an object and deriving the range from these measurements. This passive ranging device uses an iris of radius a, a lens of radius larger than a, and a photodetector of radius p

  7. Front Range Report, Abstracts

    NASA Astrophysics Data System (ADS)

    Spence, William

    The second regional conference of the Front Range Branch, AGU, was attended by more than 80 professionals and some 20 outstanding high school students. The conference included 2 days of interdisciplinary talks, and lots of discussion, that primarily were keyed to geophysical studies of Colorado, Wyoming, and New Mexico. Other talks reported on nonregional, and sometimes global, studies being done by geophypsicists of the Front Range region.Topics included tectonics of the Front Range and the Colorado Plateau, pollution of the Arkansas and Mississippi rivers, and a supreme polluting event that caused the late-Cretaceous extinctions. Other notable talks were on toxic cleanup, microburst (wind shear) detection at U.S. airports, and other meteorological studies. Several talks treated the audience to the excitement of new work and surprise discoveries. The meeting was multimedia, including the playing of two videos through a projection TV and the playing of a fascinating tape between an airport control tower and incoming pilots during a severe microburst event.

  8. Extended parametric gain range in photonic crystal fibers with strongly frequency-dependent field distributions.

    PubMed

    Petersen, Sidsel R; Alkeskjold, Thomas T; Olausson, Christina B; Lægsgaard, Jesper

    2014-08-15

    The parametric gain range of a degenerate four-wave mixing process is determined in the undepleted pump regime. The gain range is considered with and without taking the mode field distributions of the four-wave mixing components into account. It is found that the mode field distributions have to be included to evaluate the parametric gain correctly in dispersion-tailored speciality fibers and that mode profile engineering can provide a way to increase the parametric gain range.

  9. Tunable single-mode slot waveguide quantum cascade lasers

    SciTech Connect

    Meng, Bo; Tao, Jin; Quan Zeng, Yong; Wu, Sheng; Jie Wang, Qi

    2014-05-19

    We report experimental demonstration of tunable, monolithic, single-mode quantum cascade lasers (QCLs) at ∼10 μm with a two-section etched slot structure. A single-mode tuning range of 77 cm{sup −1} (785 nm), corresponding to ∼7.8% of the relative tuning range, was realized with a ∼20 dB side mode suppression ratio within the whole tuning range. Compared with integrated distributed feedback QCLs, our devices have the advantages of easy fabrication and a broader tuning range. Further theoretical analyses and numerical simulations show that it is possible to achieve a broad continuous tuning range by optimizing the slot structures. The proposed slot-waveguide design could provide an alternative but simple approach to the existing tuning schemes for realizing broadly continuous tunable single-mode QCLs.

  10. Global warming precipitation accumulation increases above the current-climate cutoff scale

    PubMed Central

    Sahany, Sandeep; Stechmann, Samuel N.; Bernstein, Diana N.

    2017-01-01

    Precipitation accumulations, integrated over rainfall events, can be affected by both intensity and duration of the storm event. Thus, although precipitation intensity is widely projected to increase under global warming, a clear framework for predicting accumulation changes has been lacking, despite the importance of accumulations for societal impacts. Theory for changes in the probability density function (pdf) of precipitation accumulations is presented with an evaluation of these changes in global climate model simulations. We show that a simple set of conditions implies roughly exponential increases in the frequency of the very largest accumulations above a physical cutoff scale, increasing with event size. The pdf exhibits an approximately power-law range where probability density drops slowly with each order of magnitude size increase, up to a cutoff at large accumulations that limits the largest events experienced in current climate. The theory predicts that the cutoff scale, controlled by the interplay of moisture convergence variance and precipitation loss, tends to increase under global warming. Thus, precisely the large accumulations above the cutoff that are currently rare will exhibit increases in the warmer climate as this cutoff is extended. This indeed occurs in the full climate model, with a 3 °C end-of-century global-average warming yielding regional increases of hundreds of percent to >1,000% in the probability density of the largest accumulations that have historical precedents. The probabilities of unprecedented accumulations are also consistent with the extension of the cutoff. PMID:28115693

  11. Global warming precipitation accumulation increases above the current-climate cutoff scale

    NASA Astrophysics Data System (ADS)

    Neelin, J. David; Sahany, Sandeep; Stechmann, Samuel N.; Bernstein, Diana N.

    2017-02-01

    Precipitation accumulations, integrated over rainfall events, can be affected by both intensity and duration of the storm event. Thus, although precipitation intensity is widely projected to increase under global warming, a clear framework for predicting accumulation changes has been lacking, despite the importance of accumulations for societal impacts. Theory for changes in the probability density function (pdf) of precipitation accumulations is presented with an evaluation of these changes in global climate model simulations. We show that a simple set of conditions implies roughly exponential increases in the frequency of the very largest accumulations above a physical cutoff scale, increasing with event size. The pdf exhibits an approximately power-law range where probability density drops slowly with each order of magnitude size increase, up to a cutoff at large accumulations that limits the largest events experienced in current climate. The theory predicts that the cutoff scale, controlled by the interplay of moisture convergence variance and precipitation loss, tends to increase under global warming. Thus, precisely the large accumulations above the cutoff that are currently rare will exhibit increases in the warmer climate as this cutoff is extended. This indeed occurs in the full climate model, with a 3 °C end-of-century global-average warming yielding regional increases of hundreds of percent to >1,000% in the probability density of the largest accumulations that have historical precedents. The probabilities of unprecedented accumulations are also consistent with the extension of the cutoff.

  12. Global warming precipitation accumulation increases above the current-climate cutoff scale.

    PubMed

    Neelin, J David; Sahany, Sandeep; Stechmann, Samuel N; Bernstein, Diana N

    2017-02-07

    Precipitation accumulations, integrated over rainfall events, can be affected by both intensity and duration of the storm event. Thus, although precipitation intensity is widely projected to increase under global warming, a clear framework for predicting accumulation changes has been lacking, despite the importance of accumulations for societal impacts. Theory for changes in the probability density function (pdf) of precipitation accumulations is presented with an evaluation of these changes in global climate model simulations. We show that a simple set of conditions implies roughly exponential increases in the frequency of the very largest accumulations above a physical cutoff scale, increasing with event size. The pdf exhibits an approximately power-law range where probability density drops slowly with each order of magnitude size increase, up to a cutoff at large accumulations that limits the largest events experienced in current climate. The theory predicts that the cutoff scale, controlled by the interplay of moisture convergence variance and precipitation loss, tends to increase under global warming. Thus, precisely the large accumulations above the cutoff that are currently rare will exhibit increases in the warmer climate as this cutoff is extended. This indeed occurs in the full climate model, with a 3 °C end-of-century global-average warming yielding regional increases of hundreds of percent to >1,000% in the probability density of the largest accumulations that have historical precedents. The probabilities of unprecedented accumulations are also consistent with the extension of the cutoff.

  13. Whispering-mode waveguide

    NASA Astrophysics Data System (ADS)

    Kurnit, N. A.

    Properties of a relatively new type of waveguide structure of potential use of confining infrared radiation to a small mode volume over long path lengths are reviewed. A single guiding surface with curvature radius rho and band radius R allows propagation of a near-grazing incidence whispering mode of transverse width approximately (lambda square root of rho R/pi) sup 1/2 and radial width approximately 1/2 (sq lambda R)/sup 1/3. For sufficiently large rho, the loss per revolution for TE mode propagation is approximately pi A/sub N/, where A/sub N/ is the normal-incidence reflection loss. Results on a number of prototype structures in general agreement with these considerations are described.

  14. Violin plate modes.

    PubMed

    Gough, Colin

    2015-01-01

    As the first step toward developing a generic model for the acoustically radiating vibrational modes of the violin and related instruments, the modes of both freely supported and edge-constrained top and back plates have been investigated as functions of shape, arching height, elastic anisotropy, the f-holes and associated island area, thickness graduations, and the additional boundary constraints of the ribs, soundpost, and bass-bar present in the assembled instrument. Comsol shell structure finite element software has been used as a quasi-experimental tool, with physical and geometric properties varied smoothly, often over several orders of magnitude, allowing the development of the plate modes to be followed continuously from those of an initially square plate to those of doubly-arched, guitar-shaped, orthotropic plates and their dependence on all the above factors.

  15. Whispering Bloch modes

    PubMed Central

    Craster, R. V.

    2016-01-01

    We investigate eigenvalue problems for the planar Helmholtz equation in open systems with a high order of rotational symmetry. The resulting solutions have similarities with the whispering gallery modes exploited in photonic micro-resonators and elsewhere, but unlike these do not necessarily require a surrounding material boundary, with confinement instead resulting from the geometry of a series of inclusions arranged in a ring. The corresponding fields exhibit angular quasi-periodicity reminiscent of Bloch waves, and hence we refer to them as whispering Bloch modes (WBMs). We show that if the geometry of the system is slightly perturbed such that the rotational symmetry is broken, modes with asymmetric field patterns can be observed, resulting in field enhancement and other potentially desirable effects. We investigate the WBMs of two specific geometries first using expansion methods and then by applying a two-scale asymptotic scheme. PMID:27493564

  16. Infernal Fishbone Mode

    SciTech Connect

    Ya.I. Kolesnichenko; V.S. Marchenko; R.B. White

    2003-02-11

    A new kind of fishbone instability associated with circulating energetic ions is predicted. The considered instability is essentially the energetic particle mode; it is characterized by m/n not equal to 1 (m and n are the poloidal and toroidal mode numbers, respectively). The mode is localized inside the flux surface where the safety factor (q) is q* = m/n, its amplitude being maximum near q*. The instability arises in plasmas with small shear inside the q* surface and q(0) > 1. A possibility to explain recent experimental observations of the m = 2 fishbone oscillations accompanied by strong changes of the neutron emission during tangential neutral-beam injection in the National Spherical Torus Experiment [M. Ono, et al., Nucl. Fusion 40 (2000) 557] is shown.

  17. Geochemistry Model Validation Report: External Accumulation Model

    SciTech Connect

    K. Zarrabi

    2001-09-27

    The purpose of this Analysis and Modeling Report (AMR) is to validate the External Accumulation Model that predicts accumulation of fissile materials in fractures and lithophysae in the rock beneath a degrading waste package (WP) in the potential monitored geologic repository at Yucca Mountain. (Lithophysae are voids in the rock having concentric shells of finely crystalline alkali feldspar, quartz, and other materials that were formed due to entrapped gas that later escaped, DOE 1998, p. A-25.) The intended use of this model is to estimate the quantities of external accumulation of fissile material for use in external criticality risk assessments for different types of degrading WPs: U.S. Department of Energy (DOE) Spent Nuclear Fuel (SNF) codisposed with High Level Waste (HLW) glass, commercial SNF, and Immobilized Plutonium Ceramic (Pu-ceramic) codisposed with HLW glass. The scope of the model validation is to (1) describe the model and the parameters used to develop the model, (2) provide rationale for selection of the parameters by comparisons with measured values, and (3) demonstrate that the parameters chosen are the most conservative selection for external criticality risk calculations. To demonstrate the applicability of the model, a Pu-ceramic WP is used as an example. The model begins with a source term from separately documented EQ6 calculations; where the source term is defined as the composition versus time of the water flowing out of a breached waste package (WP). Next, PHREEQC, is used to simulate the transport and interaction of the source term with the resident water and fractured tuff below the repository. In these simulations the primary mechanism for accumulation is mixing of the high pH, actinide-laden source term with resident water; thus lowering the pH values sufficiently for fissile minerals to become insoluble and precipitate. In the final section of the model, the outputs from PHREEQC, are processed to produce mass of accumulation

  18. Microbial accumulation of uranium, radium, and cesium

    SciTech Connect

    Strandberg, G.W.; Shumate, S.E. II; Parrott, J.R. Jr.; North, S.E.

    1981-05-01

    Diverse microbial species varied considerably in their ability to accumulate uranium, cesium, and radium. Mechanistic differences in uranium uptake by Saccharomyces cerevisiae and Pseudomonas aeruginosa were indicated. S. serevisiae exhibited a slow (hours) surface accumulation of uranium which was subject to environmental factors, while P. aeruginosa accumulated uranium rapidly (minutes) as dense intracellular deposits and did not appear to be affected by environmental parameters. Metabolism was not required for uranium uptake by either organism. Cesium and radium were concentrated to a considerably lesser extent than uranium by the several species tested.

  19. Metal accumulation in wild-caught opossum.

    PubMed

    Lockhart, J Mitchell; Siddiqui, Samreen; Loughry, W J; Bielmyer-Fraser, Gretchen K

    2016-06-01

    The Virginia opossum (Didelphis virginiana) is widespread in the USA, ranging south through Latin America. The ecology of opossums is such that they are in frequent contact with soils, suggesting that they may function as a valuable bioindicator for chemical contamination in terrestrial environments. Surprisingly, there have been virtually no toxicology studies on opossums. Here, we provide the first analysis of metal contaminants in opossum liver tissues. Liver samples were obtained from 471 opossums, collected from 2003 to 2006, at four sites in North Florida and South Georgia, USA, and concentrations of copper, lead, nickel, selenium, and zinc were measured. We found little evidence of age differences in the concentration of any of the metals. However, there were at least some significant differences between years, males and females, and between sites for each metal, although the pattern of these differences was not always consistent across metals. Concentrations of metals in liver tissue were positively correlated with one another, primarily of each metal (except Pb) with zinc. Reference levels of metal contaminants are not available for opossums, but concentrations of Cu, Ni, Pb, and Zn in our samples were for the most part significantly higher than those reported from liver tissues of nine-banded armadillos (Dasypus novemcinctus) collected at the same sites and in the same years. Data from other small mammals studied elsewhere further indicate that metal concentrations in opossums were high, but at this time, it is not possible to determine if these elevated levels generated toxicity. The substantial temporal and spatial variation we found in metal concentrations suggests that determination of baseline levels for opossums may not be straightforward. Nonetheless, this is the first study quantifying metal accumulation in the livers of Didelphis virginiana and, as such, provides an important starting point for future research.

  20. Strip mode processing of spotlight aperture radar data

    NASA Astrophysics Data System (ADS)

    di Cenzo, Alan

    1988-05-01

    The author shows how to process deramped (e.g., typical spotlight mode) synthetic-aperture-radar (SAR) data using mode processors, with no restrictions on antenna pointing. The basis of the approach is that although the deramped data does not contain a spatially invariant two-dimensional response to a point target, the range-compressed deramped data does. Range compression of the deramped data is performed simply by Fourier transforming each range line. The method greatly increases the flexibility of current strip mode processors by extending their domain to a previously unsuitable class of data.

  1. Laser range profiling for small target recognition

    NASA Astrophysics Data System (ADS)

    Steinvall, Ove; Tulldahl, Michael

    2016-05-01

    The detection and classification of small surface and airborne targets at long ranges is a growing need for naval security. Long range ID or ID at closer range of small targets has its limitations in imaging due to the demand on very high transverse sensor resolution. It is therefore motivated to look for 1D laser techniques for target ID. These include vibrometry, and laser range profiling. Vibrometry can give good results but is also sensitive to certain vibrating parts on the target being in the field of view. Laser range profiling is attractive because the maximum range can be substantial, especially for a small laser beam width. A range profiler can also be used in a scanning mode to detect targets within a certain sector. The same laser can also be used for active imaging when the target comes closer and is angular resolved. The present paper will show both experimental and simulated results for laser range profiling of small boats out to 6-7 km range and a UAV mockup at close range (1.3 km). We obtained good results with the profiling system both for target detection and recognition. Comparison of experimental and simulated range waveforms based on CAD models of the target support the idea of having a profiling system as a first recognition sensor and thus narrowing the search space for the automatic target recognition based on imaging at close ranges. The naval experiments took place in the Baltic Sea with many other active and passive EO sensors beside the profiling system. Discussion of data fusion between laser profiling and imaging systems will be given. The UAV experiments were made from the rooftop laboratory at FOI.

  2. Laser Range Camera Modeling

    SciTech Connect

    Storjohann, K.

    1990-01-01

    This paper describes an imaging model that was derived for use with a laser range camera (LRC) developed by the Advanced Intelligent Machines Division of Odetics. However, this model could be applied to any comparable imaging system. Both the derivation of the model and the determination of the LRC's intrinsic parameters are explained. For the purpose of evaluating the LRC's extrinsic parameters, i.e., its external orientation, a transformation of the LRC's imaging model into a standard camera's (SC) pinhole model is derived. By virtue of this transformation, the evaluation of the LRC's external orientation can be found by applying any SC calibration technique.

  3. Adenovirus type 2 nuclear RNA accumulating during productive infection.

    PubMed Central

    Bachenheimer, S L

    1977-01-01

    The viral-specific nuclear RNA which accumulates early and late during productive infection of HeLa cells by adenovirus-type 2 (Ad2) has been characterized with respect to its size and stability after denaturation by Me2SO. Early nuclear transcripts, under nondenaturing conditions, sediment in the range 28 to 45S, but treatment with Me2SO prior to sedimentation results in a shift to about 20S. Later nuclear RNA accumulates as a composite of two populations of molecules: one with a broad size distribution centering on 45S under nondenaturing conditions and less than 32S after denaturation and a second having a narrow size distribution around 35S which is quite stable to Me2SO. Analysis of late RNA by hybridization to Sma fragments of Ad2 DNA suggests that the 35S RNA species is derived from a limited portion of the left half of the viral genome. PMID:864839

  4. Fast Particle Resonant Modes on MST*

    NASA Astrophysics Data System (ADS)

    Koliner, J. J.; Forest, C. B.; Sarff, J. S.; Anderson, J. K.; Lin, L.; Ding, W. X.; Brower, D. L.; Spong, D. A.

    2011-10-01

    The interaction between fast particles and Alfvén eigenmodes (AE's) is an important process critical to magnetically confined fusion plasmas. An effort is in progress to understand AE's through theory and experiment on MST, a reversed-field pinch. Coupling of energetic particle dynamics to one or more continuum modes can introduce undamped AE's. This coupling can drive modes unstable, a condition pertinent to NBI on MST and fusion alpha particles in future RFP devices. Computational studies for MST have predicted toroidal AE's with frequencies in the 200-300 kHz range and global structure. Alfvén-wave-frequency modes have been observed with up to 1 MW of NBI. Toroidal and poloidal arrays of magnetic loops are utilized to find edge amplitudes, frequencies and mode numbers. Frequencies are in the 60-150 kHz range with n=4 and n=5, m=1. The strongest coherent activity scales inversely with density, as expected for AE's, but does not scale with magnetic field strength. Additional experiments to investigate resonance conditions and beam energy scaling have been performed. An FIR interferometer-polarimeter has been used to find internal structure of the detected modes through correlation analysis. *Supported by USDoE and NSF.

  5. Creating optical vortex modes with a single cylinder lens

    NASA Astrophysics Data System (ADS)

    Sridhar, Hamsa; Cohen, Martin G.; Noé, John W.

    2010-02-01

    Optical vortex (Laguerre-Gauss) modes can be created by introducing a π/2 phase shift between orthogonal components of Hermite-Gauss (HG) modes. The well-known astigmatic mode converter design described by M.W. Beijersbergen et al. [Optics Communications 96 pgs. 123 132, 1993] achieves this condition by manipulating the differing Gouy phases along orthogonal axes between a matched pair of cylinder lenses. Apparently not well known is that quite useful mode conversions can easily be achieved with a single cylinder lens. We explain the operating principle of such a single lens mode converter, and describe and illustrate how to match the input HG mode to the required Rayleigh range zΗ = fcyl with one additional spherical lens. Setting up and optimizing such a simplified mode converter is an excellent exercise for undergraduate students, and the resulting optical vortex beams can be used for a variety of instructional experiments.

  6. Mode Locking of Lasers with Atomic Layer Graphene

    DTIC Science & Technology

    2012-07-01

    saturable absorption of the atomic layer graphene different forms of passive laser mode lockers were fabricated. These are the fiber pigtailed...ranging from 1m to 2m. The vector solitons operation of a graphene mode locked erbium fiber laser was experimentally investigated. 1...or fiber lasers; d) to use the modern material fabrication techniques to improve the performance of the graphene -based mode lockers. 3

  7. Lifetimes of Hydrogen and Deuterium Related Vibrational Modes in Silicon

    SciTech Connect

    Budde, M.; Luepke, G.; Chen, E; Zhang, X.; Tolk, N. H.; Feldman, L. C.; Tarhan, E.; Ramdas, A. K.; Stavola, M.

    2001-10-01

    Lifetimes of hydrogen and deuterium related stretch modes in Si are measured by high-resolution infrared absorption spectroscopy and transient bleaching spectroscopy. The lifetimes are found to be extremely dependent on the defect structure, ranging from 2 to 295 ps. Against conventional wisdom, we find that lifetimes of Si-D modes typically are longer than for the corresponding Si-H modes. The potential implications of the results on the physics of electronic device degradation are discussed.

  8. Temperature-dependent accumulation mode particle and cloud nuclei concentrations from biogenic sources during WACS 2010

    NASA Astrophysics Data System (ADS)

    Ahlm, L.; Shakya, K. M.; Russell, L. M.; Schroder, J. C.; Wong, J. P. S.; Sjostedt, S. J.; Hayden, K. L.; Liggio, J.; Wentzell, J. J. B.; Wiebe, H. A.; Mihele, C.; Leaitch, W. R.; Macdonald, A. M.

    2013-03-01

    Submicron aerosol particles collected simultaneously at the mountain peak (2182 m a.s.l.) and at a forested mid-mountain site (1300 m a.s.l.) on Whistler Mountain, British Columbia, Canada, during June and July 2010 were analyzed by Fourier transform infrared (FTIR) spectroscopy for quantification of organic functional groups. Positive matrix factorization (PMF) was applied to the FTIR spectra. Three PMF factors associated with (1) combustion, (2) biogenics, and (3) vegetative detritus were identified at both sites. The biogenic factor was correlated with both temperature and several volatile organic compounds (VOCs). The combustion factor dominated the submicron particle mass during the beginning of the campaign, when the temperature was lower and advection was from the Vancouver area, but as the temperature started to rise in early July, the biogenic factor came to dominate as a result of increased emissions of biogenic VOCs, and thereby increased formation of secondary organic aerosol (SOA). On average, the biogenic factor represented 69% and 49% of the submicron organic particle mass at Whistler Peak and at the mid-mountain site, respectively. The lower fraction at the mid-mountain site was a result of more vegetative detritus there, and also higher influence from local combustion sources. The biogenic factor was strongly correlated (r~0.9) to number concentration of particles with diameter (Dp)> 100 nm, whereas the combustion factor was better correlated to number concentration of particles with Dp<100 nm (r~0.4). The number concentration of cloud condensation nuclei (CCN) was correlated (r~0.7) to the biogenic factor for supersaturations (S) of 0.2% or higher, which indicates that particle condensational growth from biogenic vapors was an important factor in controlling the CCN concentration for clouds where S≥0.2%. Both the number concentration of particles with Dp>100 nm and numbers of CCN for S≥0.2% were correlated to temperature. Considering the biogenic influence, these results indicate that temperature was a primary factor controlling these CCN concentrations at 0.2% supersaturation.

  9. Temperature-dependent accumulation mode particle and cloud nuclei concentrations from biogenic sources during WACS 2010

    NASA Astrophysics Data System (ADS)

    Ahlm, L.; Shakya, K. M.; Russel, L. M.; Schroder, J. C.; Wong, J. P. S.; Sjostedt, S. J.; Hayden, K. L.; Liggio, J.; Wentzell, J. J. B.; Wiebe, H. A.; Mihele, C.; Leaitch, W. R.; Macdonald, A. M.

    2012-10-01

    Submicron aerosol particles collected simultaneously at the mountain peak (2182 m a.s.l.) and at a forested mid-mountain site (1300 m a.s.l.) on Whistler Mountain, British Columbia, Canada, during June and July 2010 were analyzed by Fourier transform infrared (FTIR) spectroscopy for quantification of organic functional groups. Positive matrix factorization (PMF) was applied to the FTIR spectra. Three PMF factors associated with (1) combustion, (2) biogenics, and (3) vegetative detritus, were identified at both sites. The biogenic factor was correlated with both temperature and several volatile organic compounds (VOCs). The combustion factor dominated the submicron particle mass during the beginning of the campaign when the temperature was lower and advection was from the Vancouver area, but as the temperature started to rise in early July the biogenic factor came to dominate as a result of increased emissions of biogenic VOCs and thereby increased formation of secondary organic aerosol (SOA). On average, the biogenic factor represented 69% and 49% of the submicron organic particle mass at Whistler Peak and at the mid-mountain site, respectively. The lower fraction at the mid-mountain site was a result of more vegetative detritus there, and also higher influence from local combustion sources. The biogenic factor was strongly correlated (r ~ 0.9) to number concentration of particles with diameter (Dp)> 100 nm, whereas the combustion factor was better correlated to number concentration of particles with Dp < 100 nm (r~ 0.4). The number concentration of cloud condensation nuclei (CCN) was correlated (r ~ 0.7) to the biogenic factor for supersaturations (S) of 0.2% or higher, which indicates that particle condensational growth from biogenic vapors was an important factor in controlling the CCN concentration for clouds where S≥0.2%. Both the number concentration of particles with Dp > 100 nm and numbers of CCN for S≥0.2% were correlated to temperature. Considering the biogenic influence, these results indicate that temperature was a primary factor controlling these CCN concentrations at 0.2% supersaturation.

  10. MiniAERCam Ranging

    NASA Technical Reports Server (NTRS)

    Talley, Tom

    2003-01-01

    Johnson Space Center (JSC) is designing a small, remotely controlled vehicle that will carry two color and one black and white video cameras in space. The device will launch and retrieve from the Space Vehicle and be used for remote viewing. Off the shelf cellular technology is being used as the basis for communication system design. Existing plans include using multiple antennas to make simultaneous estimates of the azimuth of the MiniAERCam from several sites on the Space Station and use triangulation to find the location of the device. Adding range detection capability to each of the nodes on the Space Vehicle would allow an estimate of the location of the MiniAERCam to be made at each Communication And Telemetry Box (CATBox) independent of all the other communication nodes. This project will investigate the techniques used by the Global Positioning System (GPS) to achieve accurate positioning information and adapt those strategies that are appropriate to the design of the CATBox range determination system.

  11. Range Process Simulation Tool

    NASA Technical Reports Server (NTRS)

    Phillips, Dave; Haas, William; Barth, Tim; Benjamin, Perakath; Graul, Michael; Bagatourova, Olga

    2005-01-01

    Range Process Simulation Tool (RPST) is a computer program that assists managers in rapidly predicting and quantitatively assessing the operational effects of proposed technological additions to, and/or upgrades of, complex facilities and engineering systems such as the Eastern Test Range. Originally designed for application to space transportation systems, RPST is also suitable for assessing effects of proposed changes in industrial facilities and large organizations. RPST follows a model-based approach that includes finite-capacity schedule analysis and discrete-event process simulation. A component-based, scalable, open architecture makes RPST easily and rapidly tailorable for diverse applications. Specific RPST functions include: (1) definition of analysis objectives and performance metrics; (2) selection of process templates from a processtemplate library; (3) configuration of process models for detailed simulation and schedule analysis; (4) design of operations- analysis experiments; (5) schedule and simulation-based process analysis; and (6) optimization of performance by use of genetic algorithms and simulated annealing. The main benefits afforded by RPST are provision of information that can be used to reduce costs of operation and maintenance, and the capability for affordable, accurate, and reliable prediction and exploration of the consequences of many alternative proposed decisions.

  12. Western Aeronautical Test Range

    NASA Technical Reports Server (NTRS)

    Sakahara, Robert D.

    2008-01-01

    NASA's Western Aeronautical Test Range (WATR) is a network of facilities used to support aeronautical research, science missions, exploration system concepts, and space operations. The WATR resides at NASA's Dryden Flight Research Center located at Edwards Air Force Base, California. The WATR is a part of NASA's Corporate Management of Aeronautical Facilities and funded by the Strategic Capability Asset Program (SCAP). It is managed by the Aeronautics Test Program (ATP) of the Aeronautics Research Mission Directorate (ARMD) to provide the right facility at the right time. NASA is a tenant on Edwards Air Force Base and has an agreement with the Air Force Flight Test Center to use the land and airspace controlled by the Department of Defense (DoD). The topics include: 1) The WATR supports a variety of vehicles; 2) Dryden shares airspace with the AFFTC; 3) Restricted airspace, corridors, and special use areas are available for experimental aircraft; 4) WATR Products and Services; 5) WATR Support Configuration; 6) Telemetry Tracking; 7) Time Space Positioning; 8) Video; 9) Voice Communication; 10) Mobile Operations Facilities; 11) Data Processing; 12) Mission Control Center; 13) Real-Time Data Analysis; and 14) Range Safety.

  13. 40 CFR 94.220 - Service accumulation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... accumulation. (a) Each test emission data engine in the test fleet may be operated with all emission control systems operating properly for a period, up to 125 hours of operation, that is sufficient to...

  14. Waste tank ventilation system waste material accumulations

    SciTech Connect

    Van Vleet, R.J., Westinghouse Hanford

    1996-08-06

    This paper calculates the amount of material that accumulates in the ventilation systems of various Tank Waste Remediation System facilities and estimates the amount of material that could be released due to a rapid pressurization.

  15. Accumulation of nickel in transgenic tobacco

    NASA Astrophysics Data System (ADS)

    Sidik, Nik Marzuki; Othman, Noor Farhan

    2013-11-01

    The accumulation of heavy metal Ni in the roots and leaves of four T1 transgenic lines of tobacco (T(1)20E, T(1)24C, T(1)18B1 and T(1)20B) expressing eiMT1 from E.indica was assessed. The aim of the study was to investigate the level of Ni accumulation in the leaves and roots of each transgenic lines and to evaluate the eligibility of the plants to be classified as a phytoremediation agent. All of the transgenic lines showed different ability in accumulating different metals and has translocation factor (TF) less than 1 (TF<1) at all levels of metal treatment. Among the 4 transgenic lines, transgenic line T(1)24C showed the highest accumulation of Ni (251.9 ± 0.014 mg/kg) and the lowest TF value (TFT(1)24C=0.0875) at 60 ppm Ni.

  16. 19 CFR 10.534 - Accumulation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Singapore Free Trade Agreement Rules of Origin § 10.534 Accumulation. (a) Originating materials of Singapore or the United States...

  17. 19 CFR 10.534 - Accumulation.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Singapore Free Trade Agreement Rules of Origin § 10.534 Accumulation. (a) Originating materials of Singapore or the United States...

  18. 19 CFR 10.534 - Accumulation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Singapore Free Trade Agreement Rules of Origin § 10.534 Accumulation. (a) Originating materials of Singapore or the United States...

  19. 19 CFR 10.534 - Accumulation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Singapore Free Trade Agreement Rules of Origin § 10.534 Accumulation. (a) Originating materials of Singapore or the United States...

  20. 19 CFR 10.534 - Accumulation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Singapore Free Trade Agreement Rules of Origin § 10.534 Accumulation. (a) Originating materials of Singapore or the United States...

  1. Novel filtration mode for fouling limitation in membrane bioreactors.

    PubMed

    Wu, Jinling; Le-Clech, Pierre; Stuetz, Richard M; Fane, Anthony G; Chen, Vicki

    2008-08-01

    A novel filtration mode is presented to reduce fouling propensity in membrane bioreactors (MBR). During this mode, an elevated high instantaneous flux (60Lm(-2)h(-1)) is initially applied for a short time (120s), followed by a longer filtration (290s) at lower flux (10.3Lm(-2)h(-1)) and a backwash in each filtration cycle. The mixed mode is expected to limit irreversible fouling as the reversible fouling created during the initial stage appears to protect the membrane. Hydraulic performance and the components of foulants were analyzed and compared with conventional continuous and backwash modes. It was found that the mixed mode featured lower trans-membrane pressure (TMP) after 24h of filtration when compared to other modes. The mixed mode was effective in preventing soluble microbial products (SMP) attaching directly onto the membrane surface, keeping the cake layer weakly compressed, and reducing the mixed liquor suspended solids (MLSS) accumulation on the membrane. This strategy reduced the resistances of both the cake layer and the gel layer. A factorial experimental design was carried out for eight runs with different conditions to identify the major operational parameters affecting the hydraulic performances. The results showed that the value of the flux in the initial high-flux period had the most effect on the performance of the mixed mode: high initial flux (60Lm(-2)h(-1)) led to improved performance.

  2. Long range electrostatic forces in ionic liquids.

    PubMed

    Gebbie, Matthew A; Smith, Alexander M; Dobbs, Howard A; Lee, Alpha A; Warr, Gregory G; Banquy, Xavier; Valtiner, Markus; Rutland, Mark W; Israelachvili, Jacob N; Perkin, Susan; Atkin, Rob

    2017-01-19

    Ionic liquids are pure salts that are liquid under ambient conditions. As liquids composed solely of ions, the scientific consensus has been that ionic liquids have exceedingly high ionic strengths and thus very short Debye screening lengths. However, several recent experiments from laboratories around the world have reported data for the approach of two surfaces separated by ionic liquids which revealed remarkable long range forces that appear to be electrostatic in origin. Evidence has accumulated demonstrating long range surface forces for several different combinations of ionic liquids and electrically charged surfaces, as well as for concentrated mixtures of inorganic salts in solvent. The original interpretation of these forces, that ionic liquids could be envisioned as "dilute electrolytes," was controversial, and the origin of long range forces in ionic liquids remains the subject of discussion. Here we seek to collate and examine the evidence for long range surface forces in ionic liquids, identify key outstanding questions, and explore possible mechanisms underlying the origin of these long range forces. Long range surface forces in ionic liquids and other highly concentrated electrolytes hold diverse implications from designing ionic liquids for energy storage applications to rationalizing electrostatic correlations in biological self-assembly.

  3. Identification of three relationships linking cadmium accumulation to cadmium tolerance and zinc and citrate accumulation in lettuce.

    PubMed

    Zorrig, Walid; Rouached, Aïda; Shahzad, Zaigham; Abdelly, Chedly; Davidian, Jean-Claude; Berthomieu, Pierre

    2010-10-15

    Lettuce (Lactuca sativa) is a plant species that shows high accumulation of cadmium, a toxic heavy metal. Lettuce is therefore a good model both for identifying determinants controlling cadmium accumulation in plant tissues and for developing breeding strategies aimed at limiting cadmium accumulation in edible tissues. In this work, 14-day-old plants from three lettuce varieties were grown for 8 days on media supplemented with cadmium concentrations ranging from 0 to 50 microM. Growth, as well as Cd(2+), Zn(2+), K(+), Ca(2+), NO(3)(-), SO(4)(2-), Cl(-), phosphate, malate and citrate root an shoot contents were analyzed. The three lettuce varieties Paris Island Cos, Red Salad Bowl and Kordaat displayed differential abilities to accumulate cadmium in roots and shoots, Paris Island Cos displaying the lowest cadmium content and Kordaat the highest. From the global analysis of the three varieties, three main trends were identified. First, a common negative correlation linked cadmium tissue content and relative dry weight reduction in response to cadmium treatments in the three varieties. Second, increasing cadmium concentration in the culture medium resulted in a parallel increase in zinc tissue content in all lettuce varieties. A common strong positive correlation between cadmium and zinc contents was observed for all varieties. This suggested that systems enabling zinc and cadmium transport were induced by cadmium. Finally, the cadmium treatments had a contrasting effect on anion contents in tissues. Interestingly, citrate content in shoots was correlated with cadmium translocation from roots to shoots, suggesting that citrate might play a role in cadmium transport in the xylem vessels. Altogether, these results shed light on three main strategies developed by lettuce to cope with cadmium, which could help to develop breeding strategies aimed at limiting cadmium accumulation in lettuce.

  4. Stable Modes in Saturation of Instability-Driven Plasma Turbulence

    NASA Astrophysics Data System (ADS)

    Terry, P. W.

    2016-10-01

    Saturation of instability-driven plasma turbulence, apart from cases with quasilinear flattening, has been treated almost universally as an energy-transfer or wavenumber scattering process, with the Kolmogorov cascade as the idealized paradigm. This view is being modified by the realization that for a broad parameter range wavenumber transfer is subjected to heavy damping at the same scales as the instability through transfer to a separate space of stable modes. The densely populated, nonlinearly driven stable-mode space can be represented by roots of the linear dielectric or empirically extracted modes of a singular value decomposition. This new understanding of instability-driven turbulence brings to light fluctuation characteristics, transport processes, and saturation mechanisms that cannot be anticipated solely from analysis of the linear instability or the related quasilinear transport approximation. This tutorial describes key aspects of the new paradigm, including characterization of stable modes, quantitative measures of the branching ratio between wavenumber transfer and transfer to stable modes, simultaneity of transfer to stable modes as contrasted to wavenumber cascades, equipartition of energy dissipation rate among stable modes, and zonal-flow regulation of ion temperature gradient (ITG) turbulence by catalyzing transfer to stable modes. It is shown that ballooning-parity ITG turbulence creates a stochastic magnetic field by exciting a stable microtearing mode and that zonal-flow catalyzed transfer to stable modes yields a turbulence level proportional to zonal flow damping. In stellarator trapped electron mode turbulence, stable ion modes become energy driving sources via cross correlations between non orthogonal modes. Stable mode effects are shown to arise for a range of fusion plasmas systems and for astrophysically relevant Kelvin-Helmholtz instability. Supported by USDOE.

  5. An evaluation of mixed-mode delamination failure criteria

    NASA Technical Reports Server (NTRS)

    Reeder, J. R.

    1992-01-01

    Many different failure criteria have been suggested for mixed mode delamination toughness, but few sets of mixed mode data exist that are consistent over the full mode I opening to mode II shear load range. The mixed mode bending (MMB) test was used to measure the delamination toughness of a brittle epoxy composite, a state of the art toughened epoxy composite, and a tough thermoplastic composite over the full mixed mode range. To gain insight into the different failure responses of the different materials, the delamination fracture surfaces were also examined. An evaluation of several failure criteria which have been reported in the literature was performed, and the range of responses modeled by each criterion was analyzed. A new bilinear failure criterion was analyzed. A new bilinear failure criterion was developed based on a change in the failure mechanism observed from the delamination surfaces. The different criteria were compared to the failure criterion. The failure response of the tough thermoplastic composite could be modeled well with the bilinear criterion but could also be modeled with the more simple linear failure criterion. Since the materials differed in their mixed mode failure response, mixed mode delamination testing will be needed to characterize a composite material. A critical evaluation is provided of the mixed mode failure criteria and should provide general guidance for selecting an appropriate criterion for other materials.

  6. Pad-mode-induced instantaneous mode instability for simple models of brake systems

    NASA Astrophysics Data System (ADS)

    Oberst, S.; Lai, J. C. S.

    2015-10-01

    Automotive disc brake squeal is fugitive, transient and remains difficult to predict. In particular, instantaneous mode squeal observed experimentally does not seem to be associated with mode coupling and its mechanism is not clear. The effects of contact pressures, friction coefficients as well as material properties (pressure and temperature dependency and anisotropy) for brake squeal propensity have not been systematically explored. By analysing a finite element model of an isotropic pad sliding on a plate similar to that of a previously reported experimental study, pad modes have been identified and found to be stable using conventional complex eigenvalue analysis. However, by subjecting the model to contact pressure harmonic excitation for a range of pressures and friction coefficients, a forced response analysis reveals that the dissipated energy for pad modes is negative and becomes more negative with increasing contact pressures and friction coefficients, indicating the potential for instabilities. The frequency of the pad mode in the sliding direction is within the range of squeal frequencies observed experimentally. Nonlinear time series analysis of the vibration velocity also confirms the evolution of instabilities induced by pad modes as the friction coefficient increases. By extending this analysis to a more realistic but simple brake model in the form of a pad-on-disc system, in-plane pad-modes, which a complex eigenvalue analysis predicts to be stable, have also been identified by negative dissipated energy for both isotropic and anisotropic pad material properties. The influence of contact pressures on potential instabilities has been found to be more dominant than changes in material properties owing to changes in pressure or temperature. Results here suggest that instantaneous mode squeal is likely caused by in-plane pad-mode instabilities.

  7. Study Mode Negotiation.

    ERIC Educational Resources Information Center

    Vasan, Mani Le; Sargunan, Rajeswary

    This paper outlines a model of study mode negotiation between clients and English Language Training providers that has been developed at the University of Malaya, specifically related to English language writing skills as taught to corporate clients. Negotiation is used to reach decisions concerning the goals and methodology of learning to ensure…

  8. Two Modes of Sexuality.

    ERIC Educational Resources Information Center

    Firestone, Robert W.

    This paper describes the essential difference between two modes of sexual relating: (1) a personal, outward style of interaction that is the natural extension of affection, tenderness, and companionship between two people; and (2) an impersonal, inward, more masturbatory expression in which sex is used primarily as a narcotic. The origins of…

  9. Theories and Modes

    ERIC Educational Resources Information Center

    Apsche, Jack A.

    2005-01-01

    In his work on the Theory of Modes, Beck (1996) suggested that there were flaws with his cognitive theory. He suggested that though there are shortcomings to his cognitive theory, there were not similar shortcomings to the practice of Cognitive Therapy. The author suggests that if there are shortcomings to cognitive theory the same shortcomings…

  10. Thermodynamics of Radiation Modes

    ERIC Educational Resources Information Center

    Pina, Eduardo; de la Selva, Sara Maria Teresa

    2010-01-01

    We study the equilibrium thermodynamics of the electromagnetic radiation in a cavity of a given volume and temperature. We found three levels of description, the thermodynamics of one mode, the thermodynamics of the distribution of frequencies in a band by summing over the frequencies in it and the global thermodynamics by summing over all the…

  11. Synthesize Modes and Correlate

    SciTech Connect

    Mayes, Randall Lee; Hensley, Daniel P.

    2005-10-01

    SMAC is an automated experimental modal parameter extraction package which determines the natural frequencies of vibration, viscous damping ratios and mode shapes from experimental accelerance frequency response functions (FRFs). It is written in the MATLAB interpretive matrix language and has a graphical user interface.

  12. List-mode likelihood

    PubMed Central

    Barrett, Harrison H.; White, Timothy; Parra, Lucas C.

    2010-01-01

    As photon-counting imaging systems become more complex, there is a trend toward measuring more attributes of each individual event. In various imaging systems the attributes can include several position variables, time variables, and energies. If more than about four attributes are measured for each event, it is not practical to record the data in an image matrix. Instead it is more efficient to use a simple list where every attribute is stored for every event. It is the purpose of this paper to discuss the concept of likelihood for such list-mode data. We present expressions for list-mode likelihood with an arbitrary number of attributes per photon and for both preset counts and preset time. Maximization of this likelihood can lead to a practical reconstruction algorithm with list-mode data, but that aspect is covered in a separate paper [IEEE Trans. Med. Imaging (to be published)]. An expression for lesion detectability for list-mode data is also derived and compared with the corresponding expression for conventional binned data. PMID:9379247

  13. Long-range surface plasmons in electrode structures

    NASA Technical Reports Server (NTRS)

    Stegeman, G. I.; Burke, J. J.

    1983-01-01

    Surface polaritons guided by symmetric double metal film structures are analyzed, with particular attention given to the attenuation of the two long-range modes that occur. It is found that long-range surface plasmon polariton modes do exist for double electrode structures over a limited range of material parameters. Guided by thin metal electrodes, surface plasmon polaritons can achieve millimeter plus propagation distances in the near infrared. It is pointed out that if the slab is electrooptic, then very low voltages will be needed to manipulate the waves. The fact that long-range modes exist simultaneously with junction tunnel plasmons may be of use in providing directional radiation from light-emitting junctions or the inverse process of light to electrical energy conversion.

  14. Sodium accumulation in Atriplex. Final report

    SciTech Connect

    Norton, J.A.; Caldwell, M.M.; Richardson, S.G.

    1984-09-01

    This study was undertaken to determine the ecological significance and the significance to arid land reclamation of sodium accumulation and nonaccumulation in Atriplex. There was a continuum in the genetic tendency of Atriplex canescens to accumulate sodium, from populations which accumulated almost no sodium to populations which accumulated up to 7% in the leaves. There were also substantial differences in sodium uptake between populations of A. tridentata, A. falcata and A. gardneri, with some populations having less than 0.1% leaf sodium and other populations having up to 5 or 6%. In three experiments (a field study, a greenhouse pot study and a hydroponics study) there were no significant differences in salinity tolerance between sodium accumulating and nonaccumulating A. canescens: both genotypes were highly salt tolerant. There was a significant buildup of sodium in the soil beneath sodium accumulating Atriplex plants, both in natural populations and on revegetated oil shale study plots. The sodium buildup was not sufficient to be detrimental to the growth or establishment of most herbaceous species, but with older Atriplex plants or with more saline soil, the buildup could potentially be detrimental. 14 references, 42 figures, 3 tables.

  15. Range imaging laser radar

    DOEpatents

    Scott, M.W.

    1990-06-19

    A laser source is operated continuously and modulated periodically (typically sinusoidally). A receiver imposes another periodic modulation on the received optical signal, the modulated signal being detected by an array of detectors of the integrating type. Range to the target determined by measuring the phase shift of the intensity modulation on the received optical beam relative to a reference. The receiver comprises a photoemitter for converting the reflected, periodically modulated, return beam to an accordingly modulated electron stream. The electron stream is modulated by a local demodulation signal source and subsequently converted back to a photon stream by a detector. A charge coupled device (CCD) array then averages and samples the photon stream to provide an electrical signal in accordance with the photon stream. 2 figs.

  16. Range imaging laser radar

    DOEpatents

    Scott, Marion W.

    1990-01-01

    A laser source is operated continuously and modulated periodically (typicy sinusoidally). A receiver imposes another periodic modulation on the received optical signal, the modulated signal being detected by an array of detectors of the integrating type. Range to the target determined by measuring the phase shift of the intensity modulation on the received optical beam relative to a reference. The receiver comprises a photoemitter for converting the reflected, periodically modulated, return beam to an accordingly modulated electron stream. The electron stream is modulated by a local demodulation signal source and subsequently converted back to a photon stream by a detector. A charge coupled device (CCD) array then averages and samples the photon stream to provide an electrical signal in accordance with the photon stream.

  17. Variation in copper and zinc tolerance and accumulation in 12 willow clones: implications for phytoextraction.

    PubMed

    Yang, Wei-dong; Wang, Yu-yan; Zhao, Feng-liang; Ding, Zhe-li; Zhang, Xin-cheng; Zhu, Zhi-qiang; Yang, Xiao-e

    2014-09-01

    Willows (Salix spp.) have shown high potential for the phytoextraction of heavy metals. This study compares variations in copper (Cu) and zinc (Zn) tolerance and accumulation potential among 12 willow clones grown in a nutrient solution treated with 50 μmol/L of Cu or Zn, respectively. The results showed differences in the tolerance and accumulation of Cu and Zn with respect to different species/clones. The biomass variation among clones in response to Cu or Zn exposure ranged from the stimulation of growth to inhibition, and all of the clones tested showed higher tolerance to Cu than to Zn. The clones exhibited less variation in Cu accumulation but larger variation in Zn accumulation. Based on translocation factors, it was found that most of the Cu was retained in the roots and that Zn was more mobile than Cu for all clones. It is concluded that most willow clones are good accumulators of Zn and Cu.

  18. Variation in copper and zinc tolerance and accumulation in 12 willow clones: implications for phytoextraction*

    PubMed Central

    Yang, Wei-dong; Wang, Yu-yan; Zhao, Feng-liang; Ding, Zhe-li; Zhang, Xin-cheng; Zhu, Zhi-qiang; Yang, Xiao-e

    2014-01-01

    Willows (Salix spp.) have shown high potential for the phytoextraction of heavy metals. This study compares variations in copper (Cu) and zinc (Zn) tolerance and accumulation potential among 12 willow clones grown in a nutrient solution treated with 50 μmol/L of Cu or Zn, respectively. The results showed differences in the tolerance and accumulation of Cu and Zn with respect to different species/clones. The biomass variation among clones in response to Cu or Zn exposure ranged from the stimulation of growth to inhibition, and all of the clones tested showed higher tolerance to Cu than to Zn. The clones exhibited less variation in Cu accumulation but larger variation in Zn accumulation. Based on translocation factors, it was found that most of the Cu was retained in the roots and that Zn was more mobile than Cu for all clones. It is concluded that most willow clones are good accumulators of Zn and Cu. PMID:25183033

  19. Spin-wave modes of ferromagnetic films

    NASA Astrophysics Data System (ADS)

    Arias, R. E.

    2016-10-01

    The spin-wave modes of ferromagnetic films have been studied for a long time experimentally as well as theoretically, either in the magnetostatic approximation or also considering the exchange interaction. A theoretical method is presented that allows one to determine with ease the exact frequency dispersion relations of dipole-exchange modes under general conditions: an obliquely applied magnetic field, and surface boundary conditions that allow for partial pinning, which may be of different origins. The method is a generalization of Green's theorem to the problem of solving the linear dynamics of ferromagnetic spin-wave modes. Convolution integral equations for the magnetization and the magnetostatic potential of the modes are derived on the surfaces of the film. For the translation-invariant film these become simple local algebraic equations at each in-plane wave vector. Eigenfrequencies result from imposing a 6 ×6 determinant to be null, and spin-wave modes follow everywhere through solving linear 6 ×6 inhomogeneous systems. An interpretation of the results is that the Green's functions represent six independent plane-wave solutions to the equations of motion, with six associated complex perpendicular wave vectors: volume modes correspond to the cases in which two of these are purely real at a given frequency. Furthermore, the convolution extinction equations enforce the boundary conditions: this is possible at specific eigenfrequencies for a given in-plane wave vector. Magnetostatic modes may also be obtained in detail. At low frequencies and for some obliquely applied magnetic fields, magnetostatic and dipole-exchange volume modes may have forward or backward character depending on the frequency range.

  20. Whispering Gallery Mode Optomechanical Resonator

    NASA Technical Reports Server (NTRS)

    Aveline, David C.; Strekalov, Dmitry V.; Yu, Nan; Yee, Karl Y.

    2012-01-01

    Great progress has been made in both micromechanical resonators and micro-optical resonators over the past decade, and a new field has recently emerged combining these mechanical and optical systems. In such optomechanical systems, the two resonators are strongly coupled with one influencing the other, and their interaction can yield detectable optical signals that are highly sensitive to the mechanical motion. A particularly high-Q optical system is the whispering gallery mode (WGM) resonator, which has many applications ranging from stable oscillators to inertial sensor devices. There is, however, limited coupling between the optical mode and the resonator s external environment. In order to overcome this limitation, a novel type of optomechanical sensor has been developed, offering great potential for measurements of displacement, acceleration, and mass sensitivity. The proposed hybrid device combines the advantages of all-solid optical WGM resonators with high-quality micro-machined cantilevers. For direct access to the WGM inside the resonator, the idea is to radially cut precise gaps into the perimeter, fabricating a mechanical resonator within the WGM. Also, a strategy to reduce losses has been developed with optimized design of the cantilever geometry and positions of gap surfaces.

  1. Localized vibrational modes in diamond

    NASA Astrophysics Data System (ADS)

    Murzaev, R. T.; Bachurin, D. V.; Korznikova, E. A.; Dmitriev, S. V.

    2017-03-01

    Discrete breather (DB) or, synonymously, intrinsic localized mode (ILM) is a spatially localized and time-periodic vibrational mode in a defect-free nonlinear lattice, e.g., in a crystal lattice. Standing DB and DB clusters (double and triple) are studied in diamond using molecular dynamics method with the AIREBO interatomic potentials. Single DB can be easily excited by applying initial shifts, A0, to a pair of nearest atoms along the valence bond in the opposite directions. Admissible excitation amplitudes are 0.09 ≤A0 /a0 ≤ 0.12, where a0 is the equilibrium interatomic distance. The core of a DB is a pair of nearest carbon atoms oscillating out-of-phase, while the neighboring atoms oscillate with one order of magnitude lower amplitudes. DB frequency is above the top of the phonon spectrum and increases with the oscillation amplitude. DB lives for more than 100 oscillation periods which approximately corresponds to 2 ps. The range of initial amplitudes and other conditions necessary for the excitation of double and triple DB clusters as well as their lifetime are investigated in detail. Two different mechanisms of energy exchange between DBs in the DB clusters are revealed, which is the main result of the present study. Our results contribute to a deeper understanding of the nonlinear lattice dynamics of diamond.

  2. Financial Management of Distance Learning in Dual-Mode Institutions

    ERIC Educational Resources Information Center

    Rumble, Greville

    2012-01-01

    Dual-mode universities operating in a tough economic environment need to be able to answer a range of questions concerning their use of different teaching modes accurately and with confidence. Only an activity-based costing approach will provide them with this tool. Cost studies of other distance learning projects may provide benchmarks against…

  3. SERIES - Satellite Emission Range Inferred Earth Surveying

    NASA Technical Reports Server (NTRS)

    Macdoran, P. F.; Spitzmesser, D. J.; Buennagel, L. A.

    1983-01-01

    The Satellite Emission Range Inferred Earth Surveying (SERIES) concept is based on the utilization of NAVSTAR Global Positioning System (GPS) radio transmissions without any satellite modifications and in a totally passive mode. The SERIES stations are equipped with lightweight 1.5 m diameter dish antennas mounted on trailers. A series baseline measurement accuracy demonstration is considered, taking into account a 100 meter baseline estimation from approximately one hour of differential Doppler data. It is planned to conduct the next phase of experiments on a 150 m baseline. Attention is given to details regarding future baseline measurement accuracy demonstrations, aspects of ionospheric calibration in connection with subdecimeter baseline accuracy requirements of geodesy, and advantages related to the use of the differential Doppler or pseudoranging mode.

  4. Long Range Surface Plasmon Fluorescence Spectroscopy

    NASA Astrophysics Data System (ADS)

    Kasry, Amal; Knoll, Wolfgang

    2007-03-01

    Surface plasmon modes, excited at the two sides of a thin metal layer surrounded by two (nearly) identical dielectric media interact via the overlap of their electromagnetic fields. This overlap results in two new-coupled modes, a short and a long-range surface plasmon (LRSP). We demonstrate that combining the LRSP optics with fluorescence spectroscopy can result in a huge enhancement of the fluorescence signal due to the enhanced optical field of the LRSP at the metal dielectric interface, and to its increased evanescent depth into the analyte. This was demonstrated for the detection of the fluorescence intensity of chromophore labeled protein bound to the surface sensor. Beside that, some fundamentals were studied leading to some interesting difference between SPFS and LRSPFS.

  5. Radio frequency-power and the ring-mode to red-mode transition in an inductively coupled plasma

    SciTech Connect

    Coffer, J. G.; Camparo, J. C.

    2012-04-15

    The optical output of an alkali-metal inductively coupled plasma (alkali-ICP) plays an important role in both atomic magnetometers and atomic clocks, producing these devices' atomic signals through optical pumping. Unfortunately, though the alkali-ICP's optical pumping efficiency grows exponentially with temperature, at relatively high temperatures ({approx}140 deg. C) the discharge transitions from ''ring mode'' to ''red mode'', which is a spectral change in the plasma's output that corresponds broadly to a transition from ''good emission'' for optical pumping to ''poor emission.'' Recently, evidence has accumulated pointing to radiation trapping as the mechanism driving the ring-mode to red-mode transition, suggesting that the phenomenon is primarily linked to the alkali vapor's temperature. However, observations of the transition made in the 1960 s, demonstrating that the ICP temperature associated with the transition depended on rf-power, would appear to cast doubt on this mechanism. Here, we carefully investigate the influence of rf-power on the ring-mode to red-mode transition, finding that rf-power only affects the transition through discharge heating. Thus, the present work shows that the primary effect of rf-power on the ring-mode to red-mode transition can be understood in terms of the radiation trapping mechanism.

  6. High dynamic range infrared radiometry and imaging

    NASA Technical Reports Server (NTRS)

    Coon, Darryl D.; Karunasiri, R. P. G.; Bandara, K. M. S. V.

    1988-01-01

    The use is described of cryogenically cooled, extrinsic silicon infrared detectors in an unconventional mode of operation which offers an unusually large dynamic range. The system performs intensity-to-frequency conversion at the focal plane via simple circuits with very low power consumption. The incident IR intensity controls the repetition rate of short duration output pulses over a pulse rate dynamic range of about 10(6). Theory indicates the possibility of monotonic and approx. linear response over the full dynamic range. A comparison between the theoretical and the experimental results shows that the model provides a reasonably good description of experimental data. Some measurements of survivability with a very intense IR source were made on these devices and found to be very encouraging. Evidence continues to indicate that some variations in interpulse time intervals are deterministic rather than probabilistic.

  7. Geometric design of microfluidic chambers: platelet adhesion versus accumulation.

    PubMed

    Casa, Lauren D C; Ku, David N

    2014-02-01

    Arterial, platelet-rich thrombosis depends on shear rates and integrin binding to either a collagen surface or to the growing thrombus, which are mechanistically different. In general, small microfluidic test sections may favor platelet-surface adhesion without testing for the primary mode of intra-arterial thrombosis, i.e. platelet-platelet bonding and accumulation. In the present report, the ratio of platelet-platelet to platelet-surface interactions, R, and the percentage of platelet-platelet interactions, P, are estimated using an analytical approach for circular and rectangular test sections. Results show that the test section geometry strongly affects both R and P, with test section height in low-aspect ratio channels or diameter greater than 90 μm dominated by platelet-platelet interactions (R >10). Increasing rectangular test section aspect ratio decreases the required height. R increases linearly while P approaches 100 % asymptotically with increasing channel dimension. Analysis of platelet shape shows that the assumption of spherical platelets has a small effect on R compared to discoid platelets adhering flat against test section wall. However, an increase in average platelet volume resulted in a large decrease in R. Nonetheless, Monte Carlo simulations of a typical distribution of human platelet sizes show intrasubject variation in platelet size has only a 10 % net effect on R. Finally, experiments of thrombus formation show that platelet-surface lag times and platelet-platelet accumulation are similar for rectangular microfluidic test sections and round test sections when R >10. The findings show that the size of a microfluidic test section should be carefully considered in studies of cell-cell accumulation versus cell-surface adhesion.

  8. Neutron range spectrometer

    DOEpatents

    Manglos, Stephen H.

    1989-06-06

    A neutron range spectrometer and method for determining the neutron energy spectrum of a neutron emitting source are disclosed. Neutrons from the source are collimnated along a collimation axis and a position sensitive neutron counter is disposed in the path of the collimated neutron beam. The counter determines positions along the collimation axis of interactions between the neutrons in the neutron beam and a neutron-absorbing material in the counter. From the interaction positions, a computer analyzes the data and determines the neutron energy spectrum of the neutron beam. The counter is preferably shielded and a suitable neutron-absorbing material is He-3. The computer solves the following equation in the analysis: ##EQU1## where: N(x).DELTA.x=the number of neutron interactions measured between a position x and x+.DELTA.x, A.sub.i (E.sub.i).DELTA.E.sub.i =the number of incident neutrons with energy between E.sub.i and E.sub.i +.DELTA.E.sub.i, and C=C(E.sub.i)=N .sigma.(E.sub.i) where N=the number density of absorbing atoms in the position sensitive counter means and .sigma. (E.sub.i)=the average cross section of the absorbing interaction between E.sub.i and E.sub.i +.DELTA.E.sub.i.

  9. Impact of new aircraft observations Mode-S MRAR in a mesoscale NWP model

    NASA Astrophysics Data System (ADS)

    Strajnar, B.; Žagar, N.; Berre, L.

    2015-05-01

    The impact of recently available high-resolution Mode-S Meteorological Routine Air Report (MRAR) wind and temperature observations is evaluated in the mesoscale numerical weather prediction (NWP) model Aire Limitée Adaptation dynamique Développement InterNational (ALADIN). Data available from the airspace communicating with the Ljubljana Airport in Slovenia are assimilated by using the three-dimensional variational assimilation procedure on top of all other observations assimilated operationally. A data selection method based on aircraft type was shown to be important for the first application of the new observations in ALADIN. The evaluation of Mode-S MRAR impact included both winter and summer periods. In both seasons a clear improvement of wind and temperature forecasts was found for in the short forecast range, 1-3 h. The impact in the 24 h forecast range depends on season, with a consistent positive improvement of the boundary layer temperature forecasts obtained for the stable anticyclonic winter situations. In summer, the impact was mixed and it was found to be sensitive to the multivariate aspects of the moisture analysis. Overall presented results suggest that the new aircraft-derived observations Mode-S MRAR have a significant potential for mesoscale NWP and improved data assimilation modeling.

  10. Acoustic mode coupling induced by nonlinear internal waves: evaluation of the mode coupling matrices and applications.

    PubMed

    Yang, T C

    2014-02-01

    This paper applies the mode coupling equation to calculate the mode-coupling matrix for nonlinear internal waves appearing as a train of solitons. The calculation is applied to an individual soliton up to second order expansion in sound speed perturbation in the Dyson series. The expansion is valid so long as the fractional sound speed change due to a single soliton, integrated over range and depth, times the wavenumber is smaller than unity. Scattering between the solitons are included by coupling the mode coupling matrices between the solitons. Acoustic fields calculated using this mode-coupling matrix formulation are compared with that obtained using a parabolic equation (PE) code. The results agree very well in terms of the depth integrated acoustic energy at the receivers for moving solitary internal waves. The advantages of using the proposed approach are: (1) The effects of mode coupling can be studied as a function of range and time as the solitons travel along the propagation path, and (2) it allows speedy calculations of sound propagation through a packet or packets of solitons saving orders of magnitude computations compared with the PE code. The mode coupling theory is applied to at-sea data to illustrate the underlying physics.

  11. The effect of line-tying on tearing modes

    SciTech Connect

    Delzanno, Gian Luca; Finn, John M.

    2008-03-15

    Cylindrical magnetohydrodynamic (MHD) constant-{psi} or nonconstant-{psi} tearing modes that are linearly unstable with periodic axial boundary conditions are studied in a line-tied cylinder. Examples of these two respective classes of modes, with m=1 and m=2 (m being the azimuthal mode number), are studied. With a suitable MHD equilibrium, the former modes are marginally stable in ideal MHD for periodic axial boundary conditions, and occur as fast tearing modes (resistive kinks) in the presence of resistivity {eta}. The latter modes are stable in ideal MHD for periodic axial boundary conditions, and with resistivity occur as constant-{psi} tearing modes, unstable in a range of parameters. In both cases, the results for the line-tied modes show the expected tearing scaling with {eta} for very long plasmas, but the scaling becomes {gamma}{proportional_to}{eta} for smaller cylinder lengths L. These results are consistent with the following interpretation: For L{yields}{infinity}, the modes have a tearing width characteristic of tearing, leading to characteristic tearing mode growth. As L decreases, the modes develop a geometric width, which increases as L decreases; the {gamma}{proportional_to}{eta} scaling occurs when L is small enough that the geometric width exceeds the tearing width.

  12. The Burst Mode of Protostellar Accretion

    NASA Astrophysics Data System (ADS)

    Vorobyov, E. I.; Basu, Shantanu

    2006-10-01

    We present new numerical simulations in the thin disk approximation that characterize the burst mode of protostellar accretion. The burst mode begins upon the formation of a centrifugally balanced disk around a newly formed protostar. It comprises prolonged quiescent periods of low accretion rate (typically <~10-7 Msolar yr-1) that are punctuated by intense bursts of accretion (typically >~10-4 Msolar yr-1, with duration <~100 yr) during which most of the protostellar mass is accumulated. The accretion bursts are associated with the formation of dense protostellar/protoplanetary embryos, which are later driven onto the protostar by the gravitational torques that develop in the disk. Gravitational instability in the disk, driven by continuing infall from the envelope, is shown to be an effective means of transporting angular momentum outward and mass inward to the protostar. We show that the disk mass always remains significantly less than the central protostar's mass throughout this process. The burst phenomenon is robust enough to occur for a variety of initial values of rotation rate and frozen-in (supercritical) magnetic field and a variety of density-temperature relations. Even in cases where the bursts are nearly entirely suppressed, a moderate increase in cloud size or rotation rate can lead to vigorous burst activity. We conclude that most (if not all) protostars undergo a burst mode of evolution during their early accretion history, as inferred empirically from observations of FU Orionis variables.

  13. Accumulated versus continuous exercise for health benefit: a review of empirical studies.

    PubMed

    Murphy, Marie H; Blair, Steven N; Murtagh, Elaine M

    2009-01-01

    Current physical activity guidelines endorse the notion that the recommended amount of daily physical activity can be accumulated in short bouts performed over the course of a day. Although intuitively appealing, the evidence for the efficacy of accumulated exercise is not plentiful. The purpose of this review was to compare the effects of similar amounts of exercise performed in either one continuous or two or more accumulated bouts on a range of health outcomes. Sixteen studies met the selection criteria for inclusion in the review, in which at least one outcome known to affect health was measured before and after continuous and accumulated exercise training interventions. Where improvements in cardiovascular fitness were noted, most studies reported no difference in the alterations between accumulated and continuous patterns of exercise. In the few studies where a normalization of blood pressure was observed from baseline to post-intervention, there appear to be no differences between accumulated and continuous exercise in the magnitude of this effect. For other health outcomes such as adiposity, blood lipids and psychological well-being, there is insufficient evidence to determine whether accumulated exercise is as effective as the more traditional continuous approach. Seven short-term studies in which at least one health-related outcome was measured during the 0- to 48-hour period after a single continuous bout of exercise and a number of short bouts of equivalent total duration were included in the review. Many of the studies of such short-term effects considered the plasma triglyceride response to a meal following either accumulated short or continuous bouts of exercise. Collectively, these studies suggest that accumulated exercise may be as effective at reducing postprandial lipaemia. Further research is required to determine if even shorter bouts of accumulated exercise (<10 minutes) confer a health benefit and whether an accumulated approach to physical

  14. Radiation accumulation of F{sub 2} color centers in LiF crystal

    SciTech Connect

    Lisitsyna, L. A.

    2016-01-15

    The paper presents the results of the research of the F{sub 2} centers accumulation dose dependences in the LiF crystals, the kinetics of absorption relaxation initiated by exposure to a single electron pulse in the band maxima of different electron centers obtained by time-resolved spectrometry with nanosecond resolution. An analytical description of the F{sub 2} center accumulation in an absorbed dose range ≤10{sup 3} Gy is provided.

  15. Glucose-6-phosphate Reduces Calcium Accumulation in Rat Brain Endoplasmic Reticulum

    DTIC Science & Technology

    2012-04-01

    low millimolar range. Most Ca2+ is sequestered within organelles , including the endoplasmic reticulum (ER), Golgi, mitochondria , and nucleus (Carafoli...G6P and thapsigargin caused generalized reduction in Ca2+ accumulation in remarkably similar patterns with no apparent gray matter regional...with glucose-6-phosphate (10 mM) or thapsigargin (1 µM), revealed very similar pattern of generalized reduction in 45Ca2+ accumulation in gray and

  16. Neurodegeneration with Brain Iron Accumulation: Diagnosis and Management

    PubMed Central

    Hogarth, Penelope

    2015-01-01

    Neurodegeneration with brain iron accumulation (NBIA) encompasses a group of inherited disorders that share the clinical features of an extrapyramidal movement disorder accompanied by varying degrees of intellectual disability and abnormal iron deposition in the basal ganglia. The genetic basis of ten forms of NBIA is now known. The clinical features of NBIA range from rapid global neurodevelopmental regression in infancy to mild parkinsonism with minimal cognitive impairment in adulthood, with wide variation seen between and within the specific NBIA sub-type. This review describes the clinical presentations, imaging findings, pathologic features, and treatment considerations for this heterogeneous group of disorders. PMID:25614780

  17. Investigation of coherent modes and their role in intermittent oscillations using empirical mode decomposition

    NASA Astrophysics Data System (ADS)

    Shaw, Pankaj Kumar; Ghosh, Sabuj; Saha, Debajyoti; Janaki, M. S.; Iyengar, A. N. Sekar

    2016-11-01

    The paper presents an application of empirical mode decomposition (EMD) for the analysis of intermittent chaotic fluctuations from a glow discharge plasma. Here, the nature of the oscillations changes from an initial relaxation oscillation to a final chaotic oscillatory state via intermittent chaos. The time series data have been decomposed into several intrinsic mode functions (IMFs) using EMD. Furthermore, the estimation of the variance of the IMFs and the correlation of these IMFs with the original time series help us to identify the presence of coherent modes in the fluctuations. Through this analysis, we could clearly observe that initially during the relaxation oscillations the system was dominated by one type of coherent mode, whereas in the final chaotic state, it was dominated by another coherent mode. In the intermediate case, i.e., intermittent chaotic state, both the coherent modes are seen to be present. We have also used rescaled range ( R / S ) statistical method to identify the coherent modes and corroborate with the results obtained using EMD. The Hilbert Huang spectrum of the fluctuations clearly suggests the intermittent change in the frequency with time.

  18. Translating 'Asian' Modes of Healing and Biomedicine.

    PubMed

    Sleeboom-Faulkner, Margaret

    2015-01-01

    This review article discusses the 'translation of Asian modes of healing and medicine' in six recently published books by raising seven questions. They serve both to review the volumes and to ask how we have moved from understanding systems of healing in terms of tradition and modernity, science and nonscience, globalization and locality, innovation and cultural heritage, to translating them in terms of assemblages, products, modes of resistance, social (dis-)harmony, and ecological balance. The questions span subjects ranging from the meaning of 'Asian' in Asian modes of healing, the object of healing and classifications of systems of healing to their relation with 'biomedicine,' modernization and the state, the extents to which communities share healing tradition, and their existential meaning in context.

  19. On the preferred mode of jet instability

    NASA Technical Reports Server (NTRS)

    Petersen, R. A.; Samet, M. M.

    1988-01-01

    The preferred mode of instability was investigated in an axisymmetric air jet of moderate Reynolds number. Natural instabilities are shown to scale with local shear-layer thickness and the preferred mode is shown to be a shear-layer instability. The spatial evolution of the preferred mode was examined by exciting the flow acoustically and then mapping the phase-locked velocity fluctuations. Throughout the potential core region the phase-locked profiles are shown to agree with the eigensolutions of the Orr-Sommerfeld stability equations provided the calculations are based on measured, mean velocity profiles. The excitation intensity was varied from low levels, where the flow was merely tagged, to high levels where the mean flow was substantially distorted, and over that range of excitation there was no apparent deterioration in the agreement with stability predictions.

  20. Surface charge accumulation of particles containing radionuclides in open air.

    PubMed

    Kim, Yong-ha; Yiacoumi, Sotira; Tsouris, Costas

    2015-05-01

    Radioactivity can induce charge accumulation on radioactive particles. However, electrostatic interactions caused by radioactivity are typically neglected in transport modeling of radioactive plumes because it is assumed that ionizing radiation leads to charge neutralization. The assumption that electrostatic interactions caused by radioactivity are negligible is evaluated here by examining charge accumulation and neutralization on particles containing radionuclides in open air. A charge-balance model is employed to predict charge accumulation on radioactive particles. It is shown that particles containing short-lived radionuclides can be charged with multiple elementary charges through radioactive decay. The presence of radioactive particles can significantly modify the particle charge distribution in open air and yield an asymmetric bimodal charge distribution, suggesting that strong electrostatic particle interactions may occur during short- and long-range transport of radioactive particles. Possible effects of transported radioactive particles on electrical properties of the local atmosphere are reported. The study offers insight into transport characteristics of airborne radionuclides. Results are useful in atmospheric transport modeling of radioactive plumes.

  1. Surface charge accumulation of particles containing radionuclides in open air

    SciTech Connect

    Kim, Yong-ha; Yiacoumi, Sotira; Tsouris, Costas

    2015-05-01

    Radioactivity can induce charge accumulation on radioactive particles. But, electrostatic interactions caused by radioactivity are typically neglected in transport modeling of radioactive plumes because it is assumed that ionizing radiation leads to charge neutralization. The assumption that electrostatic interactions caused by radioactivity are negligible is evaluated here by examining charge accumulation and neutralization on particles containing radionuclides in open air. Moreover, a charge-balance model is employed to predict charge accumulation on radioactive particles. It is shown that particles containing short-lived radionuclides can be charged with multiple elementary charges through radioactive decay. The presence of radioactive particles can significantly modify the particle charge distribution in open air and yield an asymmetric bimodal charge distribution, suggesting that strong electrostatic particle interactions may occur during short- and long-range transport of radioactive particles. Possible effects of transported radioactive particles on electrical properties of the local atmosphere are reported. Our study offers insight into transport characteristics of airborne radionuclides. Results are useful in atmospheric transport modeling of radioactive plumes.

  2. Surface charge accumulation of particles containing radionuclides in open air

    DOE PAGES

    Kim, Yong-ha; Yiacoumi, Sotira; Tsouris, Costas

    2015-05-01

    Radioactivity can induce charge accumulation on radioactive particles. But, electrostatic interactions caused by radioactivity are typically neglected in transport modeling of radioactive plumes because it is assumed that ionizing radiation leads to charge neutralization. The assumption that electrostatic interactions caused by radioactivity are negligible is evaluated here by examining charge accumulation and neutralization on particles containing radionuclides in open air. Moreover, a charge-balance model is employed to predict charge accumulation on radioactive particles. It is shown that particles containing short-lived radionuclides can be charged with multiple elementary charges through radioactive decay. The presence of radioactive particles can significantly modify themore » particle charge distribution in open air and yield an asymmetric bimodal charge distribution, suggesting that strong electrostatic particle interactions may occur during short- and long-range transport of radioactive particles. Possible effects of transported radioactive particles on electrical properties of the local atmosphere are reported. Our study offers insight into transport characteristics of airborne radionuclides. Results are useful in atmospheric transport modeling of radioactive plumes.« less

  3. Cadmium uptake and accumulation by the decapod crustacean Penaeus indicus.

    PubMed

    Nuñez-Nogueira, Gabriel; Rainbow, Philip S

    2005-09-01

    Juveniles of the dendrobranchiate decapod Penaeus indicus take up radiolabelled cadmium from solution over the exposure concentration range of 1.8-31.5 microg L(-1), with an uptake rate constant of 0.090 L g(-1)d(-1) at 15 salinity and 25 degrees C. New cadmium taken up is added to the existing cadmium content of the prawn with no significant excretion, and the rate of accumulation of radiolabelled cadmium is a measure of the absolute cadmium uptake rate from solution. Moulting had no significant effect on the accumulation of cadmium. Newly accumulated cadmium is distributed to all organs with the highest proportions of body content being found in the hepatopancreas, exoskeleton, gills and remaining soft tissues, the hepatopancreas and gills containing the highest labelled cadmium concentrations. Like other crustaceans, penaeid prawns inhabiting anthropogenically contaminated coastal waters with raised cadmium bioavailabilities can be expected to contain raised body concentrations of cadmium. Cadmium concentrations of most field-collected adult penaeids are relatively low, as a probable consequence of the growth dilution of their cadmium contents as a result of the rapid growth rates of penaeid prawns.

  4. MONOX: a characterization tool for the X-UV range

    NASA Astrophysics Data System (ADS)

    André, J.-M.; Avila, A.; Barchewitz, R.; Benbalagh, R.; Delaunay, R.; Druart, D.; Jonnard, P.; Ringuenet, H.

    2005-08-01

    A new laboratory apparatus devoted to the characterization of various devices for the X-UV range (100 5000eV), such as mirrors, diffraction gratings, spectrometers or detectors is described. The apparatus includes open X-ray tubes as X-ray sources, a two-crystal monochromator for wavelength selection and a goniometer. Various examples of its use are presented: dispersive mode where the radiation coming from the X-ray tube is dispersed by the two-crystal monochromator, spectrometric mode where the goniometer is used as a plane X-ray spectrometer and reflectometric mode where a selected wavelength is used to perform absolute reflectivity measurements.

  5. Dual mode laser velocimeter

    NASA Technical Reports Server (NTRS)

    Gunter, William D., Jr. (Inventor); Donaldson, Ralph W. (Inventor); Anderson, Alma G., Jr. (Inventor)

    1987-01-01

    Described is a laser Doppler velocimeter (LDV) which is capable of operating with a small focus diameter for analyzing fluid flows at low velocity with high spatial resolution, or with a larger focus diameter to measure fluid flows at higher velocities accurately. More particularly, this is an LDV in which a simple reversal of a lens pair will allow it to operate in the two focus diameter modes.

  6. Geomorphic control of landscape carbon accumulation

    USGS Publications Warehouse

    Rosenbloom, N.A.; Harden, J.W.; Neff, J.C.; Schimel, D.S.

    2006-01-01

    We use the CREEP process-response model to simulate soil organic carbon accumulation in an undisturbed prairie site in Iowa. Our primary objectives are to identify spatial patterns of carbon accumulation, and explore the effect of erosion on basin-scale C accumulation. Our results point to two general findings. First, redistribution of soil carbon by erosion results in a net increase in basin-wide carbon storage relative to a noneroding environment. Landscape-average mean residence times are increased in an eroding landscape owing to the burial/preservation of otherwise labile C. Second, field observations taken along a slope transect may overlook significant intraslope variations in carbon accumulation. Spatial patterns of modeled deep C accumulation are complex. While surface carbon with its relatively short equilibration time is predictable from surface properties, deep carbon is strongly influenced by the landscape's geomorphic and climatic history, resulting in wide spatial variability. Convergence and divergence associated with upland swales and interfluves result in bimodal carbon distributions in upper and mid slopes; variability in carbon storage within modeled mid slopes was as high as simulated differences between erosional shoulders and depositional valley bottoms. The bimodality of mid-slope C variability in the model suggests that a three-dimensional sampling strategy is preferable over the traditional two-dimensional analog or "catena" approach. Copyright 2006 by the American Geophysical Union.

  7. Pulsation modes of long-period variables in the period-luminosity plane

    SciTech Connect

    Soszyński, I.; Udalski, A.; Wood, P. R. E-mail: udalski@astrouw.edu.pl

    2013-12-20

    We present a phenomenological analysis of long-period variables (LPVs) in the Large Magellanic Cloud with the aim of detecting pulsation modes associated with different period-luminosity (PL) relations. Among brighter LPVs, we discover a group of triple-mode semi-regular variables with the fundamental, first-overtone, and second-overtone modes simultaneously excited, which fall on PL sequences C, C', and B, respectively. The mode identification in the fainter red giants is more complicated. We demonstrate that the fundamental-mode pulsators partly overlap with the first-overtone modes. We show a possible range of fundamental mode and first overtone periods in the PL diagram.

  8. Combined mode I and mode II fracture of monolithic ceramics

    NASA Technical Reports Server (NTRS)

    Tikare, Veena; Choi, Sung R.

    1993-01-01

    The mode I, mode II, and combined mode I-mode II fracture behaviors of a coarse-grained silicon nitride, a fine-grained silicon nitride, and an alumina were investigated. These ceramics were fractured from two types of fracture initiating flaws: small surface flaws and large single edge precracks. The small surface flaws were introduced by Knoop indentation in flexural samples at various angles to the tensile stress direction and fractured in four-point bending. The samples with large precracks were fractured in the asymmetric four-point-bend geometry. The mixed-mode fracture toughness values obtained from the two flaw configurations were in good agreement with each other. All three ceramics displayed very similar mixed-mode fracture behavior, although their microstructures were not similar. Comparison of experimental data to mixed-mode fracture theories revealed that the minimum strain energy density theory best described the mixed-mode fracture behavior of all three ceramics.

  9. Probing plasmonic breathing modes optically

    SciTech Connect

    Krug, Markus K. Reisecker, Michael; Hohenau, Andreas; Ditlbacher, Harald; Trügler, Andreas; Hohenester, Ulrich; Krenn, Joachim R.

    2014-10-27

    The confinement of surface plasmon modes in flat nanoparticles gives rise to plasmonic breathing modes. With a vanishing net dipole moment, breathing modes do not radiate, i.e., they are optically dark. Having thus escaped optical detection, breathing modes were only recently revealed in silver nanodisks with electron energy loss spectroscopy in an electron microscope. We show that for disk diameters >200 nm, retardation induced by oblique optical illumination relaxes the optically dark character. This makes breathing modes and thus the full plasmonic mode spectrum accessible to optical spectroscopy. The experimental spectroscopy data are in excellent agreement with numerical simulations.

  10. Hippocampal pyramidal neurons switch from a multipolar migration mode to a novel "climbing" migration mode during development.

    PubMed

    Kitazawa, Ayako; Kubo, Ken-ichiro; Hayashi, Kanehiro; Matsunaga, Yuki; Ishii, Kazuhiro; Nakajima, Kazunori

    2014-01-22

    The hippocampus plays important roles in brain functions. Despite the importance of hippocampal functions, recent analyses of neuronal migration have mainly been performed on the cerebral neocortex, and the cellular mechanisms responsible for the formation of the hippocampus are not yet completely understood. Moreover, why a prolonged time is required for hippocampal neurons to complete their migration has been unexplainable for several decades. We analyzed the migratory profile of neurons in the developing mouse hippocampal CA1 region and found that the hippocampal pyramidal neurons generated near the ventricle became postmitotic multipolar cells and accumulated in the multipolar cell accumulation zone (MAZ) in the late stage of development. The hippocampal neurons passed through the pyramidal layer by a unique mode of migration. Their leading processes were highly branched and made contact with many radial fibers. Time-lapse imaging revealed that the migrating cells changed their scaffolds from the original radial fibers to other radial fibers, and as a result they proceed in a zigzag manner, with long intervals. The migrating cells in the hippocampus reminded us of "rock climbers" that instead of using their hands to pull up their bodies were using their leading processes to pull up their cell bodies. Because this mode of migration had never been described, we called it the "climbing" mode. The change from the "climbing" mode in the hippocampus to the "locomotion" mode in the neocortex may have contributed to the brain expansion during evolution.

  11. Fiber optical ranging sensor for proximity fuse

    NASA Astrophysics Data System (ADS)

    Du, Fang; Chi, Zeying; You, Mingjun; Chen, Wenjian

    1996-09-01

    A fiber optical ranging sensor used in laser proximity fuze is described in this paper. In the fuze, pulse laser diode (LD) is used as light source and trigger signal is generated by comparing the reflected light pulses with the reference pulses by a correlator after they were converted into electric signals by PIN photodiodes. Multi-mode fibers and integrated optical devices are used in the system so that the structure can be more compact. Optical fiber delay line is used to offer precise delay time for reference channel.

  12. Neoclassical Tearing Modes characterization in JET ILW operation

    NASA Astrophysics Data System (ADS)

    Baruzzo, Matteo; Alper, Barry; Angioni, Clemente; Baranov, Yuriy; Buratti, Paolo; Casson, Francis; Hender, Tim; Mantica, Paola; Marchetto, Chiara; Lauro Taroni, Laura; Valisa, Marco; JET-EFDA Contributors Team

    2014-10-01

    After several years of operation with the ITER Like Wall a comprehensive evidence on the effect of Neoclassical Tearing Modes on discharge stability and confinement has been collected. NTMs appearance is coincident with a flattening of the electron temperature profile within the island (the effect with the C-wall), but it is sometimes correlated with enhanced core plasma radiation and eventually radiative collapse. A mechanism for W accumulation in presence of magnetic island has been outlined in, where the island is responsible of connecting two radial regions characterized by different transport regimes. In this work the statistics of W accumulation measured with bolometry and Soft X-ray will be correlated with the island radial position and island width as measured by fast Electron Cyclotron Emission for different toroidal mode numbers and in different tokamak operational scenarios. JET-EFDA, Culham Science Centre, Abingdon, OX14 3DB, UK.

  13. Constraining primordial vector mode from B-mode polarization

    SciTech Connect

    Saga, Shohei; Ichiki, Kiyotomo; Shiraishi, Maresuke E-mail: maresuke.shiraishi@pd.infn.it

    2014-10-01

    The B-mode polarization spectrum of the Cosmic Microwave Background (CMB) may be the smoking gun of not only the primordial tensor mode but also of the primordial vector mode. If there exist nonzero vector-mode metric perturbations in the early Universe, they are known to be supported by anisotropic stress fluctuations of free-streaming particles such as neutrinos, and to create characteristic signatures on both the CMB temperature, E-mode, and B-mode polarization anisotropies. We place constraints on the properties of the primordial vector mode characterized by the vector-to-scalar ratio r{sub v} and the spectral index n{sub v} of the vector-shear power spectrum, from the Planck and BICEP2 B-mode data. We find that, for scale-invariant initial spectra, the ΛCDM model including the vector mode fits the data better than the model including the tensor mode. The difference in χ{sup 2} between the vector and tensor models is Δχ{sup 2} = 3.294, because, on large scales the vector mode generates smaller temperature fluctuations than the tensor mode, which is preferred for the data. In contrast, the tensor mode can fit the data set equally well if we allow a significantly blue-tilted spectrum. We find that the best-fitting tensor mode has a large blue tilt and leads to an indistinct reionization bump on larger angular scales. The slightly red-tilted vector mode supported by the current data set can also create O(10{sup -22})-Gauss magnetic fields at cosmological recombination. Our constraints should motivate research that considers models of the early Universe that involve the vector mode.

  14. Constraining primordial vector mode from B-mode polarization

    NASA Astrophysics Data System (ADS)

    Saga, Shohei; Shiraishi, Maresuke; Ichiki, Kiyotomo

    2014-10-01

    The B-mode polarization spectrum of the Cosmic Microwave Background (CMB) may be the smoking gun of not only the primordial tensor mode but also of the primordial vector mode. If there exist nonzero vector-mode metric perturbations in the early Universe, they are known to be supported by anisotropic stress fluctuations of free-streaming particles such as neutrinos, and to create characteristic signatures on both the CMB temperature, E-mode, and B-mode polarization anisotropies. We place constraints on the properties of the primordial vector mode characterized by the vector-to-scalar ratio rv and the spectral index nv of the vector-shear power spectrum, from the Planck and BICEP2 B-mode data. We find that, for scale-invariant initial spectra, the ΛCDM model including the vector mode fits the data better than the model including the tensor mode. The difference in χ2 between the vector and tensor models is Δχ2 = 3.294, because, on large scales the vector mode generates smaller temperature fluctuations than the tensor mode, which is preferred for the data. In contrast, the tensor mode can fit the data set equally well if we allow a significantly blue-tilted spectrum. We find that the best-fitting tensor mode has a large blue tilt and leads to an indistinct reionization bump on larger angular scales. The slightly red-tilted vector mode supported by the current data set can also create Script O(10-22)-Gauss magnetic fields at cosmological recombination. Our constraints should motivate research that considers models of the early Universe that involve the vector mode.

  15. Cohabitation history, marriage, and wealth accumulation.

    PubMed

    Vespa, Jonathan; Painter, Matthew A

    2011-08-01

    This study extends research on the relationship between wealth accumulation and union experiences, such as marriage and cohabitation. Using data from the National Longitudinal Survey of Youth 1979, we explore the wealth trajectories of married individuals in light of their premarital cohabitation histories. Over time, marriage positively correlates with wealth accumulation. Most married persons with a premarital cohabitation history have wealth trajectories that are indistinguishable from those without cohabitation experience, with one exception: individuals who marry their one and only cohabiting partner experience a wealth premium that is twice as large as that for married individuals who never cohabited prior to marrying. Results remain robust over time despite cohabiters' selection out of marriage, yet vary by race/ethnicity. We conclude that relationship history may shape long-term wealth accumulation, and contrary to existing literature, individuals who marry their only cohabiting partners experience a beneficial marital outcome. It is therefore important to understand the diversity of cohabitation experiences among the married.

  16. Ordinary differential equation for local accumulation time.

    PubMed

    Berezhkovskii, Alexander M

    2011-08-21

    Cell differentiation in a developing tissue is controlled by the concentration fields of signaling molecules called morphogens. Formation of these concentration fields can be described by the reaction-diffusion mechanism in which locally produced molecules diffuse through the patterned tissue and are degraded. The formation kinetics at a given point of the patterned tissue can be characterized by the local accumulation time, defined in terms of the local relaxation function. Here, we show that this time satisfies an ordinary differential equation. Using this equation one can straightforwardly determine the local accumulation time, i.e., without preliminary calculation of the relaxation function by solving the partial differential equation, as was done in previous studies. We derive this ordinary differential equation together with the accompanying boundary conditions and demonstrate that the earlier obtained results for the local accumulation time can be recovered by solving this equation.

  17. Ionizing radiation increases systemic nanoparticle tumor accumulation

    PubMed Central

    Giustini, A.J.; Petryk, A.A.; Hoopes, P.J.

    2012-01-01

    Nanoparticle-based therapies are currently being explored for both the imaging and treatment of primary and metastatic cancers. Effective nanoparticle cancer therapy requires significant accumulations of nanoparticles within the tumor environment. Various techniques have been used to improve tumor nanoparticle uptake and biodistribution. Most notable of these techniques are the use of tumor-specific-peptide-conjugated nanoparticles and chemical modification of the nanoparticles with immune-evading polymers. Another strategy for improving the tumor uptake of the nanoparticles is modification of the tumor microenvironment with a goal of enhancing the enhanced permeability and retention effect inherent to solid tumors. We demonstrate a two-fold increase in the tumor accumulation of systemically delivered iron oxide nanoparticles following a single, 15 Gy radiation dose in a syngeneic mouse breast tumor model. This increase in nanoparticle tumor accumulation correlates with a radiation-induced decrease in tumor interstitial pressure and a subsequent increase in vascular permeability. PMID:22633900

  18. Quasiperfect absorption by subwavelength acoustic panels in transmission using accumulation of resonances due to slow sound

    NASA Astrophysics Data System (ADS)

    Jiménez, Noé; Romero-García, Vicent; Pagneux, Vincent; Groby, Jean-Philippe

    2017-01-01

    We theoretically and experimentally report subwavelength resonant panels for low-frequency quasiperfect sound absorption including transmission by using the accumulation of cavity resonances due to the slow sound phenomenon. The subwavelength panel is composed of periodic horizontal slits loaded by identical Helmholtz resonators (HRs). Due to the presence of the HRs, the propagation inside each slit is strongly dispersive, with near-zero phase velocity close to the resonance of the HRs. In this slow sound regime, the frequencies of the cavity modes inside the slit are down-shifted and the slit behaves as a subwavelength resonator. Moreover, due to strong dispersion, the cavity resonances accumulate at the limit of the band gap below the resonance frequency of the HRs. Near this accumulation frequency, simultaneously symmetric and antisymmetric quasicritical coupling can be achieved. In this way, using only monopolar resonators quasiperfect absorption can be obtained in a material including transmission.

  19. Landscape Evolution and Carbon Accumulation: Uniformitarianism Revisited

    NASA Astrophysics Data System (ADS)

    Rosenbloom, N. A.; Harden, J. W.; Neff, J. C.; Schimel, D. S.

    2003-12-01

    What is the role of hillslope transport in long-term carbon accumulation in soils? How do parent material, climate, and landform interact to produce the landscapes we observe today and to what extent can we use present day conditions to infer the dominant processes of the past? We use the CREEP [Rosenbloom, N.A. et al., 2001] process-response model to ask these questions, exploring the time-evolution of landscape form, soil distribution, and carbon accumulation in an undisturbed prairie site in western Iowa [Harden, J.W. et al., 2002]. The CREEP model simulates differential transport of soil particles, blanket deposition of atmospheric 10Be with eolian dust, and passive advection of soil carbon and 10Be, enabling the preferential enrichment and burial of rapidly moving soil constituents. By comparing landscape-wide average accumulations of 10Be to borehole observations at three hillslope positions, we conclude that the distribution of clay-adsorbed 10Be cannot be explained by co-transport with clay particles alone. Rather, 10Be appears to behave as a more complex tracer than originally assumed, requiring an explicit, independent parameterization of wet deposition and transport. By comparison, model carbon accumulation strongly reflects patterns of clay redistribution indicating that in situ carbon turnover is faster than redistribution. Observed vertical distributions of soil properties, including 10Be, could only be explained by assuming variations in deposition and erosion rates, specifically periods of accumulation, followed by periods of transport. This effect might not be apparent if only landform shape, geometry, and soil depth were considered and vertical distributions of soil properties were not explicitly simulated. The current landscape reflects a history of strong shifts in erosion and accumulation rates that cannot be simulated using a uniform parameterization of long-term landscape-evolution processes.

  20. Solar p-Modes Modulated by Interior g-Modes

    NASA Astrophysics Data System (ADS)

    Lou, Yu-Qing

    2001-08-01

    The process by which frequency modulations of solar p-modes with shorter periods (~5 minutes) occur because of the presence of solar interior g-modes with longer periods (greater than a few hours approximately) is studied. The key results of a model analysis are given. In addition to the effects of stochastic excitation, this modulation by g-modes would give rise to fine spectral structures in the form of frequency sideband peaks closely packed around individual p-modes (with narrow frequency intervals on the order of g-mode frequencies) rather than of separate g-mode spectral power peaks in the low-frequency bands. For those p-modes of low degree that penetrate deep into the solar interior, this effect of frequency modulation by interior g-modes (if they exist) should be more pronounced. Observationally, individual p-modes usually contain numerous fine peaks that have to be somehow modeled (or smoothed) in order to estimate p-mode frequencies, amplitudes, and line widths, etc. By carefully weeding out noises of various origins in high-resolution p-mode frequency spectra, one might be able to extract the desired signals of g-modes trapped in the solar interior that have so far evaded the scrutiny of advanced helioseismological experiments.

  1. A racetrack mode-locked silicon evanescent laser.

    PubMed

    Fang, Alexander W; Koch, Brian R; Gan, Kian-Giap; Park, Hyundai; Jones, Richard; Cohen, Oded; Paniccia, Mario J; Blumenthal, Daniel J; Bowers, John E

    2008-01-21

    By utilizing a racetrack resonator topography, an on-chip mode locked silicon evanescent laser (ML-SEL) is realized that is independent of facet polishing. This enables integration with other devices on silicon and precise control of the ML-SEL's repetition rate through lithographic definition of the cavity length. Both passive and hybrid mode-locking have been achieved with transform limited, 7 ps pulses emitted at a repetition rate of 30 GHz. Jitter and locking range are measured under hybrid mode locking with a minimum absolute jitter and maximum locking range of 364 fs, and 50 MHz, respectively.

  2. Exploring the Cellular Accumulation of Metal Complexes

    PubMed Central

    Puckett, Cindy A.; Ernst, Russell J.; Barton, Jacqueline K.

    2010-01-01

    Transition metal complexes offer great potential as diagnostic and therapeutic agents, and a growing number of biological applications have been explored. To be effective, these complexes must reach their intended target inside the cell. Here we review the cellular accumulation of metal complexes, including their uptake, localization, and efflux. Metal complexes are taken up inside cells through various mechanisms, including passive diffusion and entry through organic and metal transporters. Emphasis is placed on the methods used to examine cellular accumulation, to identify the mechanism(s) of uptake, and to monitor possible efflux. Conjugation strategies that have been employed to improve the cellular uptake characteristics of metal complexes are also described. PMID:20104335

  3. Gyrokinetic Stability Studies of the Microtearing Mode in the National Spherical Torus Experiment H-mode

    SciTech Connect

    Baumgaertel, J. A.; Redi, M. H.; Budny, R. V.; Rewoldt, G.; Dorland, W.

    2005-10-19

    Insight into plasma microturbulence and transport is being sought using linear simulations of drift waves on the National Spherical Torus Experiment (NSTX), following a study of drift wave modes on the Alcator C-Mod Tokamak. Microturbulence is likely generated by instabilities of drift waves, which cause transport of heat and particles. Understanding this transport is important because the containment of heat and particles is required for the achievement of practical nuclear fusion. Microtearing modes may cause high heat transport through high electron thermal conductivity. It is hoped that microtearing will be stable along with good electron transport in the proposed low collisionality International Thermonuclear Experimental Reactor (ITER). Stability of the microtearing mode is investigated for conditions at mid-radius in a high density NSTX high performance (H-mode) plasma, which is compared to the proposed ITER plasmas. The microtearing mode is driven by the electron temperature gradient, and believed to be mediated by ion collisions and magnetic shear. Calculations are based on input files produced by TRXPL following TRANSP (a time-dependent transport analysis code) analysis. The variability of unstable mode growth rates is examined as a function of ion and electron collisionalities using the parallel gyrokinetic computational code GS2. Results show the microtearing mode stability dependence for a range of plasma collisionalities. Computation verifies analytic predictions that higher collisionalities than in the NSTX experiment increase microtearing instability growth rates, but that the modes are stabilized at the highest values. There is a transition of the dominant mode in the collisionality scan to ion temperature gradient character at both high and low collisionalities. The calculations suggest that plasma electron thermal confinement may be greatly improved in the low-collisionality ITER.

  4. Minimizing Modes for Smart Selection in Sketching/Drawing Interfaces

    NASA Astrophysics Data System (ADS)

    Saund, Eric; Lank, Edward

    User interface modes are ubiquitous in both mouse-keyboard and pen-based user interfaces, but the requirement for prior setting of a user interface mode before performing an action imposes a persistent drag on system usability. This chapter reviews our research in approaches to avoiding prior deliberate mode setting while still allowing overloading of fundamental tap and gesture operations. We analyze the human-machine dynamics of UI protocols through a graphical notation called the Interaction Flow Diagram. Our framework offers a pyramid of methods ranging from simple UI design techniques, through recognition of gestures and canvas content, to modeling of user knowledge and goals. These are represented in four methods: Overloaded Loop Selection to infer rectangle versus lasso selection mode; the Inferred Mode Protocol for Inferring Draw/Select Mode; the Sloppy Selection method for inferring intended content of an ambiguous selection; and the Cycle Tap Selection Method for exploiting structure recognition.

  5. Gyrokinetic Theory for Arbitrary Wavelength Electromagnetic Modes in Tokamaks

    SciTech Connect

    Qin, H.; Rewoldt, G.; Tang, W.M.

    1997-10-01

    A linear gyrokinetic system for arbitrary wavelength electromagnetic modes is developed. A wide range of modes in inhomogeneous plasmas, such as the internal kink modes, the toroidal Alfvén eigenmode (TAE) modes, and the drift modes, can be recovered from this system. The inclusion of most of the interesting physical factors into a single framework enables us to look at many familiar modes simultaneously and thus to study the modifications of and the interactions between them in a systematic way. Especially, we are able to investigate self-consistently the kinetic MHD phenomena entirely from the kinetic side. Phase space Lagrangian Lie perturbation methods and a newly developed computer algebra package for vector analysis in general coordinate system are utilized in the analytical derivation. In tokamak geometries, a 2D finite element code has been developed and tested. In this paper, we present the basic theoretical formalism and some of the preliminary results.

  6. Mode Tracker for Mode-Hop-Free Operation of a Laser

    NASA Technical Reports Server (NTRS)

    Wysocki, Gerard; Tittel, Frank K.; Curl, Robert F.

    2010-01-01

    A mode-tracking system that includes a mode-controlling subsystem has been incorporated into an external-cavity (EC) quantum cascade laser that operates in a mid-infrared wavelength range. The mode-tracking system makes it possible to perform mode-hop-free wavelength scans, as needed for high-resolution spectroscopy and detection of trace gases. The laser includes a gain chip, a beam-collimating lens, and a diffraction grating. The grating is mounted on a platform, the position of which can be varied to effect independent control of the EC length and the grating angle. The position actuators include a piezoelectric stage for translation control and a motorized stage for coarse rotation control equipped with a piezoelectric actuator for fine rotation control. Together, these actuators enable control of the EC length over a range of about 90 m with a resolution of 0.9 nm, and control of the grating angle over a coarse-tuning range of +/-6.3deg and a fine-tuning range of +/-520 microrad with a resolution of 10 nrad. A mirror mounted on the platform with the grating assures always the same direction of the output laser beam.

  7. MODE: Structural Test Article (STA)

    NASA Technical Reports Server (NTRS)

    Crawley, Edward F.; Masters, Brett

    1992-01-01

    Viewgraphs on the Middeck 0-gravity Dynamics Experiment (MODE): Structural Test Article (STA) are presented. Topics covered include: MODE: structural test article motivation; hardware; sensors and actuators; experimental support module; data; preliminary results; supporting analysis program; and modeling approach.

  8. I-mode for ITER?

    NASA Astrophysics Data System (ADS)

    Whyte, D. G.; Marmar, E.; Hubbard, A.; Hughes, J.; Dominguez, A.; Greenwald, M.

    2011-10-01

    I-mode is a recently explored confinement regime that features a temperature pedestal and H-mode energy confinement, yet with L-mode particle confinement and no density pedestal nor large ELMs. Experiments on Alcator C-Mod and ASDEX-Upgrade show this leads to a stationary collisionless pedestal that inherently does not require ELMs for core impurity and particle control, possibly making I-mode an attractive operating regime for ITER where ELM heat pulses are expected to surpass material limits. We speculate as to how I-mode could be obtained, maintained and exploited for the ITER burning plasma physics mission. Issues examined include I-mode topology and power threshold requirements, pedestal formation, density control, avoiding H-mode, and the response of I-mode to alpha self-heating. Key uncertainties requiring further investigation are identified. Supported by the US DOE Cooperative Agreement DE-FC02-99ER54512.

  9. MODE: Structural Test Article (STA)

    NASA Astrophysics Data System (ADS)

    Crawley, Edward F.; Masters, Brett

    Viewgraphs on the Middeck 0-gravity Dynamics Experiment (MODE): Structural Test Article (STA) are presented. Topics covered include: MODE: structural test article motivation; hardware; sensors and actuators; experimental support module; data; preliminary results; supporting analysis program; and modeling approach.

  10. A bilinear failure criterion for mixed-mode delamination

    NASA Technical Reports Server (NTRS)

    Reeder, James R.

    1993-01-01

    Many different failure criteria have been suggested for mixed-mode delamination toughness, but few sets of mixed-mode data exist that are consistent over the full range of Mode 1 opening load to Mode 2 shear load range. The mixed-mode bending (MMB) test was used to measure the delamination toughness of a brittle epoxy composite, a state-of-the-art toughened epoxy composite, and a tough thermoplastic composite over the full mixed-mode range. To gain insight into the different failure responses of the different materials, the delamination fracture surfaces were also examined. An evaluation of several failure criteria that have been reported in the literature was performed, and the range of responses modeled by each criterion was analyzed. A bilinear failure criterion was introduced based on a change in the failure mechanism observed from the delamination surfaces. The different criteria were compared to the failure response of the three materials tested. The responses of the two epoxies were best modeled with the new bilinear failure criterion. The failure response of the tough thermoplastic composite could be modeled well with the bilinear criterion but could also be modeled with the more simple linear failure criterion. Since the materials differed in their mixed-mode failure response, mixed-mode delamination testing will be needed to characterize a composite material. This paper presents consistent sets of mixed-mode data, provides a critical evaluation of the mixed-mode failure criteria, and should provide general guidance for selecting an appropriate criterion for other materials.

  11. Exact order reduction in mode conversion

    NASA Astrophysics Data System (ADS)

    Swanson, D. G.

    1997-11-01

    The Exact Order Reduction method(S. Johnston, D. G. Swanson, Bull. Am. Phys. Soc. 41), 1425., which solves the mode conversion equations obtained from the Vlasov equations with high accuracy is shown to work over a broad range of parameters. The results for the scattering parameters are close to the corresponding results from the dispersion relation method, typically within a few percent. The technique is both faster and more robust (converging over a broader range of parameters), as well as solving the most highly accurate set of mode conversion equations. Results both with k_y=3D0 (incidence in midplane) and k_yne0 (oblique incidence) will be presented. abstract.

  12. Final Environmental Impact Statement for Proposed Barry M. Goldwater Range East Range Enhancements (Including First and Second Record of Decision)

    DTIC Science & Technology

    2010-10-01

    Resources Geology The mountain ranges are formed of Precambrian to Tertiary-aged igneous , metamorphic, and sedimentary rocks . Valley fill...main rock types— igneous , metamorphic, and sedimentary. All or portions of seven named mountain ranges are found in the vicinity of BMGR East. The BMGR...actions. Desert pavement is a flat surface covered with a complete layer of tightly spaced pebbles, gravel, or rocks varnished by a slow accumulation

  13. Attenuation of free spheroidal oscillations of the Earth after the M = 9 Earthquake in Sumatra and the super-deep Earthquake in the Sea of Okhotsk: I. the Admissible Q-factor range for the fundamental mode and overtones of the free spheroidal oscillations

    NASA Astrophysics Data System (ADS)

    Molodenskii, S. M.; Molodenskaya, M. S.

    2015-11-01

    The problem of reconstructing the depth distribution of density and the depth and frequency dependences of the mechanical Q-factor in the Earth's mantle from the entire set of the present-day seismic and astrometric data on the travel times and periods of seismic waves and the amplitudes and phases of forced nutations is considered. The solution of the problem is refined by including the new data about the attenuation of the free oscillations of the Earth excited by the Sumatra earthquake ( M = 9) and super-deep earthquake in the Sea of Okhotsk. The actual accuracy of the Q-factor is studied in the first part of the paper. To this end, we analyze (1) the convergence of the Q-factor estimated from the time series of different length shifted along the time axis and (2) the convergence of the results based on the different data. Since the accuracy of identifying all the periods and attenuation factors for the free oscillations from the Sumatra earthquake is significantly higher than for the earthquake with M = 9 in Japan, the data are only compared for the Sumatra and Okhotsk events. The signal-to-noise ratio (SNR) is analyzed based on the records from different Global Seismographic Network (GSN) stations including the station in Obninsk, the Kurchatov station in Kazakhstan, and the main ERM and MAJO stations in Japan. It is found that the highest SNR was observed in Obninsk. The inverse problem of reconstructing the density and Q-factor is solved for the frequency dependent real parts of the shear moduli with allowance for the most accurate data about the attenuation factors for the fundamental spheroidal modes of the free oscillations of the Earth.

  14. Triple mode Cepheid masses

    NASA Technical Reports Server (NTRS)

    King, D. S.; Cox, A. N.; Hodson, S. W.

    1980-01-01

    Unconventional composition structures are proposed to explain the periods of the triple mode Cepheid aC And. A strong Cepheid wind appears to enrich helium in the convection zones down to about 60,000 K or 70,000 K. Then some downward partial mixing occurs to the bottom of a layer with about 1-q = .0005 of the stellar mass. It was found that AC And was not unlike anomalous Cepheids. However, masses of betwen one and two solar masses are suggested and the population is more likely a type two.

  15. Shear mode grinding

    SciTech Connect

    Brown, N.J.; Fuchs, B.A.

    1989-04-24

    The thesis of this paper is that shear mode grinding of glass (1) occurs with abrasive particle sizes less than 1/mu/m, (2) that it is the mechanical limit of the the more common mechanical-chemical glass polishing, and (3) that the debris is insufficient in size to perform the function of eroding the binder in the grinding wheel and thus necessitates the addition of an abrasive and/or chemical additions to the coolant to effect wheel-dressing. 13 refs.

  16. Damage mechanics - failure modes

    SciTech Connect

    Krajcinovic, D.; Vujosevic, M.

    1996-12-31

    The present study summarizes the results of the DOE sponsored research program focused on the brittle failure of solids with disordered microstructure. The failure is related to the stochastic processes on the microstructural scale; namely, the nucleation and growth of microcracks. The intrinsic failure modes, such as the percolation, localization and creep rupture, are studied by emphasizing the effect of the micro-structural disorder. A rich spectrum of physical phenomena and new concepts that emerges from this research demonstrates the reasons behind the limitations of traditional, deterministic, and local continuum models.

  17. Dual mode warhead

    SciTech Connect

    Obrsky, J.; Alexander, A.A.; Griffen, O.H.; Foster, J.S.; Shamblen, M.

    1980-12-31

    A dual mode warhead is provided for use against both soft and hard targets and capable of sensing which type of target has been struck comprising a casing made of a ductile material containing an explosive charge and a fuze assembly. The ductile warhead casing will mushroom and later split upon striking a hard target while still confining the explosive. Proper ductility and confinement are necessary for fuze sensing. The fuze assembly contains a pair of parallel firing trains, one initiated only by high and one by low impact deceleration. The firing train actuated by low impact deceleration contains a pyrotechnic delay to allow penetration of soft targets.

  18. ACCA College English Teaching Mode

    ERIC Educational Resources Information Center

    Ding, Renlun

    2008-01-01

    This paper elucidates a new college English teaching mode--"ACCA" (Autonomous Cooperative Class-teaching All-round College English Teaching Mode). Integrated theories such as autonomous learning and cooperative learning into one teaching mode, "ACCA", which is being developed and advanced in practice as well, is the achievement…

  19. Standardization of Keyword Search Mode

    ERIC Educational Resources Information Center

    Su, Di

    2010-01-01

    In spite of its popularity, keyword search mode has not been standardized. Though information professionals are quick to adapt to various presentations of keyword search mode, novice end-users may find keyword search confusing. This article compares keyword search mode in some major reference databases and calls for standardization. (Contains 3…

  20. Accumulation of contaminants in fish from wastewater treatment wetlands

    USGS Publications Warehouse

    Barber, L.B.; Keefe, S.H.; Antweiler, R.C.; Taylor, H.E.; Wass, R.D.

    2006-01-01

    Increasing demands on water resources in arid environments make reclamation and reuse of municipal wastewater an important component of the water budget. Treatment wetlands can be an integral part of the water-reuse cycle providing both water-quality enhancement and habitat functions. When used for habitat, the bioaccumulation potential of contaminants in the wastewater is a critical consideration. Water and fish samples collected from the Tres Rios Demonstration Constructed Wetlands near Phoenix, Arizona, which uses secondary-treated wastewater to maintain an aquatic ecosystem in a desert environment, were analyzed for hydrophobic organic compounds (HOC) and trace elements. Semipermeable membrane devices (SPMD) were deployed to investigate uptake of HOC. The wetlands effectively removed HOC, and concentrations of herbicides, pesticides, and organic wastewater contaminants decreased 40-99% between inlet and outlet. Analysis of Tilapia mossambica and Gambusia affinis indicated accumulation of HOC, including p,p???-DDE and trans-nonachlor. The SPMD accumulated the HOC detected in the fish tissue as well as additional compounds. Trace-element concentrations in whole-fish tissue were highly variable, but were similar between the two species. Concentrations of HOC and trace elements varied in different fish tissue compartments, and concentrations in Tilapia liver tissue were greater than those in the whole organism or filet tissue. Bioconcentration factors for the trace elements ranged from 5 to 58 000 and for the HOC ranged from 530 to 150 000. ?? 2006 American Chemical Society.

  1. Kinetics of a chlorate-accumulating, perchlorate-reducing bacterium.

    PubMed

    Dudley, Margaret; Salamone, Anna; Nerenberg, Robert

    2008-05-01

    Kinetics parameters for perchlorate and chlorate reduction were determined for Dechlorosoma sp. HCAP-C, also known as Dechlorosoma sp. PCC, a novel perchlorate-reducing bacterium (PCRB) that accumulates significant amounts of chlorate during perchlorate reduction. This is the first report of such behavior, and we hypothesized the perchlorate reduction kinetics would be markedly different from other PCRB. In batch tests with initial perchlorate concentrations ranging from 200 to around 1400 mg/L, maximum chlorate accumulation ranged from 41 to 279 mg/L, and were consistently around 20% of the initial perchlorate concentration. For perchlorate, parameters were determined using a competitive inhibition model. The maximum specific substrate degradation rate qmaxP was 11.5mgClO4-/mgdry weight (DW)-d, and the half-maximum rate constant KP was 193 mgClO4-/L. For chlorate, the qmaxC was 8.3 mgClO3-/mgDW-d and the KC was 58.3 mgClO3-/L. The high KP values relative to conventional PCRB, values suggests that HCAP-C does not play a significant role at low perchlorate concentrations. However, the relatively high qmaxP, and the potential for syntrophic relationships with chlorate-reducing bacteria that relieve the effects of chlorate inhibition, suggest that HCAP-C could play a significant role at high perchlorate concentrations.

  2. Nonlinear excitation of long-wavelength modes in Hall plasmas

    NASA Astrophysics Data System (ADS)

    Lakhin, V. P.; Ilgisonis, V. I.; Smolyakov, A. I.; Sorokina, E. A.

    2016-10-01

    Hall plasmas with magnetized electrons and unmagnetized ions exhibit a wide range of small scale fluctuations in the lower-hybrid frequency range as well as low-frequency large scale modes. Modulational instability of lower-hybrid frequency modes is investigated in this work for typical conditions in Hall plasma devices such as magnetrons and Hall thrusters. In these conditions, the dispersion of the waves in the lower-hybrid frequency range propagating perpendicular to the external magnetic field is due to the gradients of the magnetic field and the plasma density. It is shown that such lower-hybrid modes are unstable with respect to the secondary instability of the large scale quasimode perturbations. It is suggested that the large scale slow coherent modes observed in a number of Hall plasma devices may be explained as a result of such secondary instabilities.

  3. RF SYSTEM FOR THE SNS ACCUMULATOR RING.

    SciTech Connect

    BLASKIEWICZ, M.; BRENNAN, J.M.; BRODOWSKI, J.; DELONG, J.; METH, M.; SMITH, K.; ZALTSMAN, A.

    2001-06-18

    During accumulation the RF beam current in the spallation neutron source ring rises from 0 to 50 amperes. A clean, 250 nanosecond gap is needed for the extraction kicker risetime. Large momentum spread and small peak current are needed to prevent instabilities and stopband related losses. A robust RF system meeting these requirements has been designed.

  4. Plastic accumulation in the Mediterranean sea.

    PubMed

    Cózar, Andrés; Sanz-Martín, Marina; Martí, Elisa; González-Gordillo, J Ignacio; Ubeda, Bárbara; Gálvez, José Á; Irigoien, Xabier; Duarte, Carlos M

    2015-01-01

    Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2), as well as its frequency of occurrence (100% of the sites sampled), are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by millimeter-sized fragments, but showed a higher proportion of large plastic objects than that present in oceanic gyres, reflecting the closer connection with pollution sources. The accumulation of floating plastic in the Mediterranean Sea (between 1,000 and 3,000 tons) is likely related to the high human pressure together with the hydrodynamics of this semi-enclosed basin, with outflow mainly occurring through a deep water layer. Given the biological richness and concentration of economic activities in the Mediterranean Sea, the affects of plastic pollution on marine and human life are expected to be particularly frequent in this plastic accumulation region.

  5. 19 CFR 10.917 - Accumulation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 1 2012-04-01 2012-04-01 false Accumulation. 10.917 Section 10.917 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Peru Trade Promotion...

  6. 19 CFR 10.917 - Accumulation.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 1 2013-04-01 2013-04-01 false Accumulation. 10.917 Section 10.917 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Peru Trade Promotion...

  7. 19 CFR 10.917 - Accumulation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 1 2014-04-01 2014-04-01 false Accumulation. 10.917 Section 10.917 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Peru Trade Promotion...

  8. 19 CFR 10.1017 - Accumulation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 1 2012-04-01 2012-04-01 false Accumulation. 10.1017 Section 10.1017 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Korea Free Trade Agreement...

  9. 19 CFR 10.1017 - Accumulation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 1 2014-04-01 2014-04-01 false Accumulation. 10.1017 Section 10.1017 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Korea Free Trade Agreement...

  10. 19 CFR 10.1017 - Accumulation.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 1 2013-04-01 2013-04-01 false Accumulation. 10.1017 Section 10.1017 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Korea Free Trade Agreement...

  11. 19 CFR 10.597 - Accumulation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Accumulation. 10.597 Section 10.597 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. Dominican Republic-Central...

  12. 19 CFR 10.772 - Accumulation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Accumulation. 10.772 Section 10.772 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Morocco Free Trade...

  13. Plastic Accumulation in the Mediterranean Sea

    PubMed Central

    Cózar, Andrés; Sanz-Martín, Marina; Martí, Elisa; González-Gordillo, J. Ignacio; Ubeda, Bárbara; Gálvez, José Á.; Irigoien, Xabier; Duarte, Carlos M.

    2015-01-01

    Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2), as well as its frequency of occurrence (100% of the sites sampled), are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by millimeter-sized fragments, but showed a higher proportion of large plastic objects than that present in oceanic gyres, reflecting the closer connection with pollution sources. The accumulation of floating plastic in the Mediterranean Sea (between 1,000 and 3,000 tons) is likely related to the high human pressure together with the hydrodynamics of this semi-enclosed basin, with outflow mainly occurring through a deep water layer. Given the biological richness and concentration of economic activities in the Mediterranean Sea, the affects of plastic pollution on marine and human life are expected to be particularly frequent in this plastic accumulation region. PMID:25831129

  14. Genetics Home Reference: actin-accumulation myopathy

    MedlinePlus

    ... fibers and are important for muscle contraction. Attachment (binding) and release of the overlapping thick and thin filaments allows them to move relative to each other so that the muscles can contract. ACTA1 gene mutations that cause actin-accumulation myopathy ...

  15. 19 CFR 10.772 - Accumulation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 1 2011-04-01 2011-04-01 false Accumulation. 10.772 Section 10.772 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Morocco Free Trade...

  16. 19 CFR 10.772 - Accumulation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 1 2014-04-01 2014-04-01 false Accumulation. 10.772 Section 10.772 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Morocco Free Trade...

  17. 19 CFR 10.772 - Accumulation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 1 2012-04-01 2012-04-01 false Accumulation. 10.772 Section 10.772 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Morocco Free Trade...

  18. 19 CFR 10.772 - Accumulation.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 1 2013-04-01 2013-04-01 false Accumulation. 10.772 Section 10.772 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Morocco Free Trade...

  19. Hippocampal Networks Habituate as Novelty Accumulates

    ERIC Educational Resources Information Center

    Murty, Vishnu P.; Ballard, Ian C.; Macduffie, Katherine E.; Krebs, Ruth M.; Adcock, R. Alison

    2013-01-01

    Novelty detection, a critical computation within the medial temporal lobe (MTL) memory system, necessarily depends on prior experience. The current study used functional magnetic resonance imaging (fMRI) in humans to investigate dynamic changes in MTL activation and functional connectivity as experience with novelty accumulates. fMRI data were…

  20. 19 CFR 10.458 - Accumulation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Chile Free Trade Agreement Rules of Origin § 10.458 Accumulation. (a) Originating goods or materials of Chile or the United States... of Chile, the United States, or both, by one or more producers, will be considered as an...

  1. Copper accumulation in the crayfish (Orconectes rusticus)

    SciTech Connect

    Evans, M.L.

    1980-06-01

    The purpose of this study was to determine whether or not the crayfish, O. rusticus could fulfill Nehring's (1976) criteria for a good biological monitor of heavy metal pollution. Since there is some evidence that the cupric ion is the most toxic form of aqueous copper, crayfish-accumulated copper was compared to both total and cupric copper in the culture water.

  2. Enhanced default mode network connectivity with ventral striatum in Subthreshold depression individuals

    PubMed Central

    Hwang, J.W.; Xin, S.C.; Ou, Y.M.; Zhang, W.Y.; Liang, Y.L.; Chen, J.; Yang, X.Q.; Chen, X.Y.; Guo, T.W.; Yang, X.J.; Ma, W.H.; Li, J.; Zhao, B.C.; Tu, Y.; Kong, J.

    2016-01-01

    Subthreshold depression (StD) is a highly prevalent condition associated with increased service utilization and social morbidity. Nevertheless, due to limitations in current diagnostic systems that set the boundary for major depressive disorder (MDD), very few brain imaging studies on the neurobiology of StD have been carried out, and its underlying neurobiological mechanism remains unclear. In recent years, accumulating evidence suggests that the disruption of the default mode network (DMN), a network involved in self-referential processing, affective cognition, and emotion regulation, is involved in major depressive disorder. Using independent component analysis, we investigated resting-state default mode network (DMN) functional connectivity (FC) changes in two cohorts of StD patients with different age ranges (young and middle-aged, n= 57) as well as matched controls (n=79). We found significant FC increase between the DMN and ventral striatum (key region in the reward network), in both cohorts of StD patients in comparison with controls. In addition, we also found the FC between the DMN and ventral striatum was positively and significantly associated with scores on the Center for Epidemiologic Studies Depression Scale (CES-D), a measurement of depressive symptomatology. We speculate that this enhanced FC between the DMN and the ventral striatum may reflect a self-compensation to the lowered reward function. PMID:26922247

  3. Lipid Accumulation in Hypoxic Tissue Culture Cells

    PubMed Central

    Gordon, Gerald B.; Barcza, Maureen A.; Bush, Marilyn E.

    1977-01-01

    Lipid droplets have long been recognized by light microscopy to accumulate in hypoxic cells both in vivo and in vitro. In the present tissue culture experiments, correlative electron microscopic observations and lipid analyses were performed to determine the nature and significance of lipid accumulation in hypoxia. Strain L mouse fibroblasts were grown in suspension culture, both aerobically and under severe oxygen restriction obtained by gassing cultures daily with an 8% CO2-92% nitrogen mixture. After 48 hours, hypoxic cells showed an increase in total lipid/protein ratio of 42% over control cells. Most of this increase was accounted for by an elevation in the level of cellular triglyceride from 12.3 ± 0.9 μg/mg cell protein in aerobic cultures to 41.9 ± 0.7 in the hypoxic cultures, an increase of 240%. Levels of cellular free fatty acids (FFA) were 96% higher in the hypoxic cultures. No significant changes in the levels of cellular phospholipid or cholesterol were noted. Electron microscopic examination revealed the accumulation of homogeneous cytoplasmic droplets. The hypoxic changes were reversible upon transferring the cultures to aerobic atmospheres with disappearance of the lipid. These experiments indicate that hypoxic injury initially results in triglyceride and FFA accumulation from an inability to oxidize fatty acids taken up from the media and not from autophagic processes, as described in other types of cell injury associated with the sequestration of membranous residues and intracellular cholesterol and phospholipid accumulation. ImagesFigure 3Figure 4Figure 5Figure 6Figure 7Figure 1Figure 2 PMID:196505

  4. Tear film MMP accumulation and corneal disease

    PubMed Central

    Smith, V; Rishmawi, H; Hussein, H; Easty, D

    2001-01-01

    BACKGROUND/AIMS—Matrix metalloproteinases (MMPs) accumulate in the tears of patients with active peripheral ulcerative keratitis (PUK) but it is unknown whether these enzymes have a central role in disease progression. The aims of the present investigation were to determine the source of these enzymes and to ascertain whether their accumulation in tears is a phenomenon specific to PUK or a general feature of other anterior segment diseases.
METHODS—The experimental samples were obtained from the culture media of conjunctival and corneal epithelial cells, from fractionated blood plasma and leucocytes of healthy subjects and patients with rheumatoid arthritis, and from the tears of healthy subjects and patients with a variety of anterior segment diseases. The MMPs of all samples were visualised by zymography and tear samples were assayed using nitrophenol acetate and an MMP-9 susceptible quenched fluorescent peptide as substrate.
RESULTS—The major MMPs that accumulate in the tears of patients with rheumatoid arthritis with active ocular disease are MMP-9 and a species of Mr 116 000. By comparing the zymographic activity profiles of the gelatinases present in the samples obtained, it was deduced that the main source of these MMPs was granulocytes. Their accumulation in tears was not unique to patients with PUK; detectable amounts of the enzymes also occurred in the tears of patients with keratoconus with associated atopic disease, patients undergoing treatment for herpetic eye disease, and patients with systemic and non-systemic dry eye disease.
CONCLUSION—The MMPs that accumulate in tears are mainly derived from granulocytes. This may be effected by autoimmune diseases that involve ocular tissue or by ocular diseases that induce an inflammatory response.

 PMID:11159476

  5. Holographic thermalization with initial long range correlation

    SciTech Connect

    Lin, Shu

    2016-01-19

    Here, we studied the evolution of the Wightman correlator in a thermalizing state modeled by AdS3-Vaidya background. A prescription was given for calculating the Wightman correlator in coordinate space without using any approximation. For equal-time correlator , we obtained an enhancement factor v2 due to long range correlation present in the initial state. This was missed by previous studies based on geodesic approximation. Moreover, we found that the long range correlation in initial state does not lead to significant modification to thermalization time as compared to known results with generic initial state. We also studied the spatially integrated Wightman correlator and showed evidence on the distinction between long distance and small momentum physics for an out-of-equilibrium state. We also calculated the radiation spectrum of particles weakly coupled to O and found that lower frequency mode approaches thermal spectrum faster than high frequency mode.

  6. Improved feedback control of wall stabilized kink modes with different plasma-wall couplings and mode rotation

    NASA Astrophysics Data System (ADS)

    Peng, Q.; Levesque, J. P.; Stoafer, C. C.; Bialek, J.; Byrne, P.; Hughes, P. E.; Mauel, M. E.; Navratil, G. A.; Rhodes, D. J.

    2016-04-01

    A new algorithm for feedback control of rotating, wall-stabilized kink modes in the High Beta Tokamak-Extended Pulse (HBT-EP) device maintains an accurate phase shift between the perturbation and the measured rotating mode through current control, with control power emphasizing fast rotation and phase jumps over fast amplitude changes. In HBT-EP, wall-stabilized kink modes become unstable above the ideal wall stability limit, and feedback suppression is aimed at delaying the onset of discharge disruption through reduction of the kink mode amplitude. Performance of the new feedback algorithm is tested under different experimental conditions, including variation of the plasma-wall coupling, insertion of a ferritic wall, changing mode rotation frequency over the range of 4-8 kHz using an internal biased electrode, and adjusting the feedback phase-angle to accelerate, amplify, or suppress the mode. We find the previously reported excitation of the slowly rotating mode at high feedback gain in HBT-EP is mitigated by the current control scheme. We also find good agreement between the observed and predicted changes to the mode rotation frequency and amplitude. When ferritic material is introduced, or the plasma-wall coupling becomes weaker as the walls are retracted from plasma, the feedback gain needs to be increased to achieve the same level of suppression. When mode rotation is slowed by a biased electrode, the feedback system still achieves mode suppression, and demonstrates wide bandwidth effectiveness.

  7. The Aerosol Coarse Mode Initiative

    NASA Astrophysics Data System (ADS)

    Arnott, W. P.; Adhikari, N.; Air, D.; Kassianov, E.; Barnard, J.

    2014-12-01

    Many areas of the world show an aerosol volume distribution with a significant coarse mode and sometimes a dominant coarse mode. The large coarse mode is usually due to dust, but sea salt aerosol can also play an important role. However, in many field campaigns, the coarse mode tends to be ignored, because it is difficult to measure. This lack of measurements leads directly to a concomitant "lack of analysis" of this mode. Because, coarse mode aerosols can have significant effects on radiative forcing, both in the shortwave and longwave spectrum, the coarse mode -- and these forcings -- should be accounted for in atmospheric models. Forcings based only on fine mode aerosols have the potential to be misleading. In this paper we describe examples of large coarse modes that occur in areas of large aerosol loading (Mexico City, Barnard et al., 2010) as well as small loadings (Sacramento, CA; Kassianov et al., 2012; and Reno, NV). We then demonstrate that: (1) the coarse mode can contribute significantly to radiative forcing, relative to the fine mode, and (2) neglecting the coarse mode may result in poor comparisons between measurements and models. Next we describe -- in general terms -- the limitations of instrumentation to measure the coarse mode. Finally, we suggest a new initiative aimed at examining coarse mode aerosol generation mechanisms; transport and deposition; chemical composition; visible and thermal IR refractive indices; morphology; microphysical behavior when deposited on snow and ice; and specific instrumentation needs. Barnard, J. C., J. D. Fast, G. Paredes-Miranda, W. P. Arnott, and A. Laskin, 2010: Technical Note: Evaluation of the WRF-Chem "Aerosol Chemical to Aerosol Optical Properties" Module using data from the MILAGRO campaign, Atmospheric Chemistry and Physics, 10, 7325-7340. Kassianov, E. I., M. S. Pekour, and J. C. Barnard, 2012: Aerosols in Central California: Unexpectedly large contribution of coarse mode to aerosol radiative forcing

  8. SAMPEX Spin Stabilized Mode

    NASA Technical Reports Server (NTRS)

    Tsai, Dean C.; Markley, F. Landis; Watson, Todd P.

    2008-01-01

    The Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX), the first of the Small Explorer series of spacecraft, was launched on July 3, 1992 into an 82' inclination orbit with an apogee of 670 km and a perigee of 520 km and a mission lifetime goal of 3 years. After more than 15 years of continuous operation, the reaction wheel began to fail on August 18,2007. With a set of three magnetic torquer bars being the only remaining attitude actuator, the SAMPEX recovery team decided to deviate from its original attitude control system design and put the spacecraft into a spin stabilized mode. The necessary operations had not been used for many years, which posed a challenge. However, on September 25, 2007, the spacecraft was successfully spun up to 1.0 rpm about its pitch axis, which points at the sun. This paper describes the diagnosis of the anomaly, the analysis of flight data, the simulation of the spacecraft dynamics, and the procedures used to recover the spacecraft to spin stabilized mode.

  9. Modes of fossil preservation

    USGS Publications Warehouse

    Schopf, J.M.

    1975-01-01

    The processes of geologic preservation are important for understanding the organisms represented by fossils. Some fossil differences are due to basic differences in organization of animals and plants, but the interpretation of fossils has also tended to be influenced by modes of preservation. Four modes of preservation generally can be distinguished: (1) Cellular permineralization ("petrifaction") preserves anatomical detail, and, occasionally, even cytologic structures. (2) Coalified compression, best illustrated by structures from coal but characteristic of many plant fossils in shale, preserves anatomical details in distorted form and produces surface replicas (impressions) on enclosing matrix. (3) Authigenic preservation replicates surface form or outline (molds and casts) prior to distortion by compression and, depending on cementation and timing, may intergrade with fossils that have been subject to compression. (4) Duripartic (hard part) preservation is characteristic of fossil skeletal remains, predominantly animal. Molds, pseudomorphs, or casts may form as bulk replacements following dissolution of the original fossil material, usually by leaching. Classification of the kinds of preservation in fossils will aid in identifying the processes responsible for modifying the fossil remains of both animals and plants. ?? 1975.

  10. Single-Mode VISAR

    SciTech Connect

    Krauter, Kerry

    2007-11-28

    High energy-density physics (HEDP) experiments examine the properties of materials under extreme conditions. These experiments rely on the measurement of one or two velocities. These velocities are used to obtain Hugoniot relationships and thermodynamic equations of state. This methodology is referred to as 'velocimetry' and an instrument used to measure the shock wave is called a 'velocimeter' or a '(velocity) diagnostic'. The two most-widely used existing velocity diagnostics are; photonic Doppler velocimetry (PDV) and velocity interferometer system for any reflector (VISAR). PDV's advantages are a fast rise-time and ease of implementation but PDV has an upper velocity limit. Traditional implementations of VISAR have a rise time 10 times slower than PDV and are not easily implemented but are capable of measuring any velocity produced during HEDP experiments. This thesis describes a novel method of combining the positive attributes of PDV and VISAR into a more cost effective diagnostic called a Single-Mode VISAR (SMV). The new diagnostic will consist of PDV parts in a VISAR configuration. This configuration will enable the measurement of any velocity produced during shock physics experiments while the components used to build the diagnostic will give the diagnostic a fast rise time and make it easy to use. This thesis describes the process of building and testing the first single-mode VISAR. The tests include verifying the performance of the components and the diagnostic as a whole.

  11. A Wide Dynamic Range Tapped Linear Array Image Sensor

    NASA Astrophysics Data System (ADS)

    Washkurak, William D.; Chamberlain, Savvas G.; Prince, N. Daryl

    1988-08-01

    Detectors for acousto-optic signal processing applications require fast transient response as well as wide dynamic range. There are two major choices of detectors: conductive or integration mode. Conductive mode detectors have an initial transient period before they reach then' i equilibrium state. The duration of 1 his period is dependent on light level as well as detector capacitance. At low light levels a conductive mode detector is very slow; response time is typically on the order of milliseconds. Generally. to obtain fast transient response an integrating mode detector is preferred. With integrating mode detectors. the dynamic range is determined by the charge storage capability of the tran-sport shift registers and the noise level of the image sensor. The conventional net hod used to improve dynamic range is to increase the shift register charge storage capability. To achieve a dynamic range of fifty thousand assuming two hundred noise equivalent electrons, a charge storage capability of ten million electrons would be required. In order to accommodate this amount of charge. unrealistic shift registers widths would be required. Therefore, with an integrating mode detector it is difficult to achieve a dynamic range of over four orders of magnitude of input light intensity. Another alternative is to solve the problem at the photodetector aml not the shift, register. DALSA's wide dynamic range detector utilizes an optimized, ion implant doped, profiled MOSFET photodetector specifically designed for wide dynamic range. When this new detector operates at high speed and at low light levels the photons are collected and stored in an integrating fashion. However. at bright light levels where transient periods are short, the detector switches into a conductive mode. The light intensity is logarithmically compressed into small charge packets, easily carried by the CCD shift register. As a result of the logarithmic conversion, dynamic ranges of over six orders of

  12. Drift mode accelerometry for spaceborne gravity measurements

    NASA Astrophysics Data System (ADS)

    Conklin, John W.

    2015-11-01

    A drift mode accelerometer is a precision instrument for spacecraft that overcomes much of the acceleration noise and readout dynamic range limitations of traditional electrostatic accelerometers. It has the potential of achieving acceleration noise performance similar to that of drag-free systems over a restricted frequency band without the need for external drag-free control or continuous spacecraft propulsion. Like traditional accelerometers, the drift mode accelerometer contains a high-density test mass surrounded by an electrode housing, which can control and sense all six degrees of freedom of the test mass. Unlike traditional accelerometers, the suspension system is operated with a low duty cycle so that the limiting suspension force noise only acts over brief, known time intervals, which can be neglected in the data analysis. The readout is performed using a laser interferometer which is immune to the dynamic range limitations of even the best voltage references typically used to determine the inertial acceleration of electrostatic accelerometers. The drift mode accelerometer is a novel offshoot of the like-named operational mode of the LISA Pathfinder spacecraft, in which its test mass suspension system is cycled on and off to estimate the acceleration noise associated with the front-end electronics. This paper presents the concept of a drift mode accelerometer, describes the operation of such a device, develops models for its performance with respect to non-drag-free satellite geodesy and gravitational wave missions, and discusses plans for testing the performance of a prototype sensor in the laboratory using torsion pendula.

  13. Long-term accumulation and transport of anthropogenic phosphorus in world river basins

    NASA Astrophysics Data System (ADS)

    Powers, S. M.

    2015-12-01

    Global food production crucially depends on phosphorus (P). In agricultural and urban landscapes, much P is anthropogenic, entering via trade, and then can be transported by a combination of fluvial and human processes. To date there have been few long-term, large-scale analyses combining both fluvial and human modes of P transport. Here we present reconstructed historical records of anthropogenic P entering and leaving soils and aquatic systems via a combination of trade, infrastructure, food waste, and fluvial fluxes. We then report the net annual P inputs, and the mass of P that has accumulated over the long-term, for entire river basins. Our analyses reveal rapid historical P accumulation for two mixed agricultural-urban landscapes (Thames Basin, UK, Yangtze Basin, China), and one rural agricultural landscape (Maumee Basin, USA). We also show that the human P fluxes massively dominate over the fluvial fluxes in these large basins. For Thames and Maumee Basins, recently there has been modest P depletion/drawdown of the massive P pool accumulated in prior decades, whereas the Yangtze Basin has consistently and rapidly accumulated P since 1980. These first estimates of the magnitude of historical P accumulation in contrasting settings illustrate the scope of management challenges surrounding the storage, fate, exploitation, and reactivation of legacy P that is currently present in the Earth's critical zone.

  14. Expanded mode lasers for telecommunications applications

    NASA Astrophysics Data System (ADS)

    Lealman, Ian F.

    This thesis describes the development of a long wavelength (1.55 μm) expanded mode semiconductor laser. The increased spot size of the laser improves both the coupling efficiency to cleaved fibre and fibre alignment tolerances and reduces packaging cost. In this type of device the strength of the waveguide is gradually reduced towards the front facet allowing the mode to adiabatically expand so that the laser mode is better matched in size to that of a cleaved fibre. This can be achieved by either reducing the refractive index of the guide or reducing the amount of material in the core. The structure chosen was a buried heterostructure laser that utilised a twin guide consisting of an upper higher refractive index guide (the active region of the laser) above a weak passive guide. The width of the active region was reduced along part of the device allowing the mode to expand into the weak underlying guide. The guide structure was optimised using a variable grid finite difference mode solver, and the taper length calculated by an approximation to Love's method. Detailed results are presented for the measured light-current characteristic, farfield and coupling loss to cleaved fibre. These coupling losses were compared to the calculated data thus allowing the waveguide design to be optimised. Several iterations in the design of the device were undertaken, with the aim of reducing the coupling loss to cleaved single mode fibre without significantly compromising the laser performance. The final device design had extremely low coupling losses as low as 1.2 dB to cleaved fibre. Finally, the positive impact this device had on passive alignment using a silicon motherboard is examined, and the application this technology to a range of other optoelectronic components is discussed.

  15. Surface vibrational modes in disk-shaped resonators.

    PubMed

    Dmitriev, A V; Gritsenko, D S; Mitrofanov, V P

    2014-03-01

    The natural frequencies and distributions of displacement components for the surface vibrational modes in thin isotropic elastic disks are calculated. In particular, the research is focused on even solutions for low-lying resonant vibrations with large angular wave numbers. Several families of modes are found which are interpreted as modified surface modes of an infinitely long cylinder and Lamb modes of a plate. The results of calculation are compared with the results of the experimental measurements of vibrational modes generated by means of resonant excitation in duraluminum disk with radius of ≈90 mm and thickness of 16 mm in the frequency range of 130-200 kHz. An excellent agreement between the calculated and measured frequencies is found. Measurements of the structure of the resonant peaks show splitting of some modes. About a half of the measured modes has splitting Δfsplit/fmode at the level of the order of 10(-5). The Q-factors of all modes measured in vacuum lie in the interval (2…3)×10(5). This value is typical for duraluminum mechanical resonators in the ultrasonic frequency range.

  16. Vlasov equation for long-range interactions on a lattice.

    PubMed

    Bachelard, R; Dauxois, T; De Ninno, G; Ruffo, S; Staniscia, F

    2011-06-01

    We show that, in the continuum limit, the dynamics of Hamiltonian systems defined on a lattice with long-range couplings is well described by the Vlasov equation. This equation can be linearized around the homogeneous state, and a dispersion relation, which depends explicitly on the Fourier modes of the lattice, can be derived. This allows one to compute the stability thresholds of the homogeneous state, which turns out to depend on the mode number. When this state is unstable, the growth rates are also functions of the mode number. Explicit calculations are performed for the α-Hamiltonian mean field model with 0≤α<1, for which the mean-field mode is always found to dominate the exponential growth. The theoretical predictions are successfully compared with numerical simulations performed on a finite lattice.

  17. Robust single-mode all-solid multi-trench fiber with large effective mode area.

    PubMed

    Jain, Deepak; Jung, Yongmin; Kim, Jaesun; Sahu, Jayanta K

    2014-09-01

    We experimentally demonstrate all-solid 30 and 90 μm core diameter multi-trench fibers. Measurements ensure an effective single-mode operation over a wide range of bend radius in the case of 30 μm core fiber, making it suitable for applications like beam delivery and compact fiber lasers. On the other hand, a 90 μm core fiber ensures an effective single-mode operation and shows good potential for rod-type fiber laser applications. Both fibers were fabricated by the conventional modified chemical vapor deposition process in conjunction with the rod-in-tube technique, hence making them suitable for mass production.

  18. Alcohol sensor based on single-mode-multimode-single-mode fiber structure

    NASA Astrophysics Data System (ADS)

    Mefina Yulias, R.; Hatta, A. M.; Sekartedjo, Sekartedjo

    2016-11-01

    Alcohol sensor based on Single-mode -Multimode-Single-mode (SMS) fiber structure is being proposed to sense alcohol concentration in alcohol-water mixtures. This proposed sensor uses refractive index sensing as its sensing principle. Fabricated SMS fiber structure had 40 m of multimode length. With power input -6 dBm and wavelength 1550 nm, the proposed sensor showed good response with sensitivity 1,983 dB per % v/v with measurement range 05 % v/v and measurement span 0,5% v/v.

  19. Accumulation of radionuclides by plants as a monitor system.

    PubMed Central

    Koranda, J J; Robison, W L

    1978-01-01

    The accumulation of radionuclides by plants acting as a monitoring system in the environment may occur by two modes; foliar absorption by the leaves and shoot of the plant, or by root uptake from the soil. Data on plant accumulation of radionuclides may be obtained from studies of fission product radionuclides deposited as worldwide fallout, and from tracer studies of plant physiology. The epidermal features of plant foliage may exert an effect upon particle retention by leaves, and subsequent uptake of radionuclides from the surface. The transport of radionuclides across the cuticle and epidermis of plant leaves is determined in part by the anatomy of the leaf, and by physiological factors. The foliar uptake of fallout radionuclides, 99Sr, 131I, and 137Cs, is described with examples from the scientific literature. The environmental half-life of 131I, for example, is considerably shorter than its physical half-life because of physical and biological factors which may produce a half-life as short as 0.23/day. 99Sr and 137Cs are readily taken up by the leaf, but 137Cs undergoes more translocation into fruit and seeds than 99Sr which tends to remain in the plant part in which it was initially absorbed. Soil-root uptake is conditioned primarily by soil chemical and physical factors which may selectively retain a radionuclide, such as 137Cs. The presence of organic matter, inorganic colloids (clay), and competing elements will strongly affect the uptake of 99Sr and 137Cs by plants from the soil. The role of plants as monitors of radionuclides is twofold: as monitors of recent atmospheric releases of radionuclides; and as indicators of the long-term behavior of aged deposits of radionuclides in the soil. PMID:367767

  20. 26 CFR 1.535-3 - Accumulated earnings credit.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 7 2013-04-01 2013-04-01 false Accumulated earnings credit. 1.535-3 Section 1... Accumulated earnings credit. (a) In general. As provided in section 535(a) and § 1.535-1, the accumulated earnings credit, provided by section 535(c), reduces taxable income in computing accumulated taxable...

  1. 26 CFR 1.535-3 - Accumulated earnings credit.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 7 2010-04-01 2010-04-01 true Accumulated earnings credit. 1.535-3 Section 1... Accumulated earnings credit. (a) In general. As provided in section 535(a) and § 1.535-1, the accumulated earnings credit, provided by section 535(c), reduces taxable income in computing accumulated taxable...

  2. 26 CFR 1.535-3 - Accumulated earnings credit.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 7 2012-04-01 2012-04-01 false Accumulated earnings credit. 1.535-3 Section 1... Accumulated earnings credit. (a) In general. As provided in section 535(a) and § 1.535-1, the accumulated earnings credit, provided by section 535(c), reduces taxable income in computing accumulated taxable...

  3. 26 CFR 1.535-3 - Accumulated earnings credit.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 7 2011-04-01 2009-04-01 true Accumulated earnings credit. 1.535-3 Section 1... Accumulated earnings credit. (a) In general. As provided in section 535(a) and § 1.535-1, the accumulated earnings credit, provided by section 535(c), reduces taxable income in computing accumulated taxable...

  4. Geometric Effects on the Amplification of First Mode Instability Waves

    NASA Technical Reports Server (NTRS)

    Kirk, Lindsay C.; Candler, Graham V.

    2013-01-01

    The effects of geometric changes on the amplification of first mode instability waves in an external supersonic boundary layer were investigated using numerical techniques. Boundary layer stability was analyzed at Mach 6 conditions similar to freestream conditions obtained in quiet ground test facilities so that results obtained in this study may be applied to future test article design to measure first mode instability waves. The DAKOTA optimization software package was used to optimize an axisymmetric geometry to maximize the amplification of the waves at first mode frequencies as computed by the 2D STABL hypersonic boundary layer stability analysis tool. First, geometric parameters such as nose radius, cone half angle, vehicle length, and surface curvature were examined separately to determine the individual effects on the first mode amplification. Finally, all geometric parameters were allowed to vary to produce a shape optimized to maximize the amplification of first mode instability waves while minimizing the amplification of second mode instability waves. Since first mode waves are known to be most unstable in the form of oblique wave, the geometries were optimized using a broad range of wave frequencies as well as a wide range of oblique wave angles to determine the geometry that most amplifies the first mode waves. Since first mode waves are seen most often in flows with low Mach numbers at the edge of the boundary layer, the edge Mach number for each geometry was recorded to determine any relationship between edge Mach number and the stability of first mode waves. Results indicate that an axisymmetric cone with a sharp nose and a slight flare at the aft end under the Mach 6 freestream conditions used here will lower the Mach number at the edge of the boundary layer to less than 4, and the corresponding stability analysis showed maximum first mode N factors of 3.

  5. Stability of organic carbon accumulating in Spartina alterniflora-dominated salt marshes of the Mid-Atlantic U.S.

    NASA Astrophysics Data System (ADS)

    Unger, Viktoria; Elsey-Quirk, Tracy; Sommerfield, Christopher; Velinsky, David

    2016-12-01

    Organic carbon sequestration in salt marsh soils is a function of factors that influence both spatial variability and chemical stability of accumulating carbon. Refractory carbon (slowly decomposed) may be the most important in terms of long-term sequestration and is widely referred to in models of carbon storage; however, little information exists about the quantity and variability of refractory carbon accumulation in marshes. In this study, total (CT), labile (CL) and refractory (CR) organic carbon accumulation rates were measured for Spartina alterniflora-dominated marshes representing different geomorphological settings with a range of vertical accretion rates. Three 50-cm long cores were collected in each of three marshes in Barnegat Bay and three marshes in Delaware Estuary, USA. Rates of C accumulation were calculated using Cesium-137 dating and the relative stability of soil organic carbon was quantified using acid-hydrolysis. CT accumulation ranged over fourfold among marshes from 72 to 346 g m-2 yr-1. CT and CL accumulation increased with increasing mineral sediment accumulation, while CR accumulation was uniform across cores averaging 78 ± 5 g m-2 yr-1. Similar rates of CR accumulation across marsh areas with different accretion and mineral sediment accumulation rates was associated with a decline in the CR:CL density ratio as mineral volume increased. Our results suggest that carbon accumulation is higher in salt marshes with higher mineral sedimentation due, primarily, to the burial of labile carbon, and that there is a limit on the rate of chemically recalcitrant carbon accumulation in marsh soils.

  6. Selenoprotein P Inhibits Radiation-Induced Late Reactive Oxygen Species Accumulation and Normal Cell Injury

    SciTech Connect

    Eckers, Jaimee C.; Kalen, Amanda L.; Xiao, Wusheng; Sarsour, Ehab H.; Goswami, Prabhat C.

    2013-11-01

    Purpose: Radiation is a common mode of cancer therapy whose outcome is often limited because of normal tissue toxicity. We have shown previously that the accumulation of radiation-induced late reactive oxygen species (ROS) precedes cell death, suggesting that metabolic oxidative stress could regulate cellular radiation response. The purpose of this study was to investigate whether selenoprotein P (SEPP1), a major supplier of selenium to tissues and an antioxidant, regulates late ROS accumulation and toxicity in irradiated normal human fibroblasts (NHFs). Methods and Materials: Flow cytometry analysis of cell viability, cell cycle phase distribution, and dihydroethidium oxidation, along with clonogenic assays, were used to measure oxidative stress and toxicity. Human antioxidant mechanisms array and quantitative real-time polymerase chain reaction assays were used to measure gene expression during late ROS accumulation in irradiated NHFs. Sodium selenite addition and SEPP1 overexpression were used to determine the causality of SEPP1 regulating late ROS accumulation and toxicity in irradiated NHFs. Results: Irradiated NHFs showed late ROS accumulation (4.5-fold increase from control; P<.05) that occurs after activation of the cell cycle checkpoint pathways and precedes cell death. The mRNA levels of CuZn- and Mn-superoxide dismutase, catalase, peroxiredoxin 3, and thioredoxin reductase 1 increased approximately 2- to 3-fold, whereas mRNA levels of cold shock domain containing E1 and SEPP1 increased more than 6-fold (P<.05). The addition of sodium selenite before the radiation treatment suppressed toxicity (45%; P<.05). SEPP1 overexpression suppressed radiation-induced late ROS accumulation (35%; P<.05) and protected NHFs from radiation-induced toxicity (58%; P<.05). Conclusion: SEPP1 mitigates radiation-induced late ROS accumulation and normal cell injury.

  7. Mixed Mode Matrix Multiplication

    SciTech Connect

    Meng-Shiou Wu; Srinivas Aluru; Ricky A. Kendall

    2004-09-30

    In modern clustering environments where the memory hierarchy has many layers (distributed memory, shared memory layer, cache,...), an important question is how to fully utilize all available resources and identify the most dominant layer in certain computations. When combining algorithms on all layers together, what would be the best method to get the best performance out of all the resources we have? Mixed mode programming model that uses thread programming on the shared memory layer and message passing programming on the distributed memory layer is a method that many researchers are using to utilize the memory resources. In this paper, they take an algorithmic approach that uses matrix multiplication as a tool to show how cache algorithms affect the performance of both shared memory and distributed memory algorithms. They show that with good underlying cache algorithm, overall performance is stable. When underlying cache algorithm is bad, superlinear speedup may occur, and an increasing number of threads may also improve performance.

  8. Dual-Mode Combustion

    NASA Technical Reports Server (NTRS)

    Goyne, Christopher P.; McDaniel, James C.

    2002-01-01

    The Department of Mechanical and Aerospace Engineering at the University of Virginia has conducted an investigation of the mixing and combustion processes in a hydrogen fueled dual-mode scramjet combustor. The experiment essentially consisted of the "direct connect" continuous operation of a Mach 2 rectangular combustor with a single unswept ramp fuel injector. The stagnation enthalpy of the test flow simulated a flight Mach number of 5. Measurements were obtained using conventional wall instrumentation and laser based diagnostics. These diagnostics included, pressure and wall temperature measurements, Fuel Plume Imaging (FPI) and Particle Image Velocimetry (PIV). A schematic of the combustor configuration and a summary of the measurements obtained are presented. The experimental work at UVa was parallel by Computational Fluid Dynamics (CFD) work at NASA Langley. The numerical and experiment results are compared in this document.

  9. Mode-mode fiber interferometer with impact localization ability

    NASA Astrophysics Data System (ADS)

    Kotov, Oleg; Chapalo, Ivan

    2016-04-01

    In this publication we investigate distributed mode-mode fiber interferometer (MFI) with ability of external impact localization. It is based on bidirectional continuous selective excitation of multimode fiber (MMF) with increasing of launched modes quantity along the MMF from excitation point to the opposite end of fiber. Two photo detection systems register output signals from both directions. MFI output signal characteristics such as amplitude and spectrum width depend on excited modes quantity at the point of perturbation. Thus, every fiber point is characterized by two opposite direction signal parameters. Calculating these parameters' values makes it possible to localize the segment subjected by external impact. Experimental MFI setup include 3 MMF segments with 2 mode controllers among them which increase excited modes number from segment to segment. During the experiment, every MMF segment was subjected by arbitrary external perturbations and output signals were analyzed. Obtained results confirmed the ability of localization.

  10. Multidecadal time series of satellite-detected accumulations of cyanobacteria in the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Kahru, M.; Elmgren, R.

    2014-07-01

    Cyanobacteria, primarily of the species Nodularia spumigena, form extensive surface accumulations in the Baltic Sea in July and August, ranging from diffuse flakes to dense surface scums. The area of these accumulations can reach ~ 200 000 km2. We describe the compilation of a 35-year-long time series (1979-2013) of cyanobacteria surface accumulations in the Baltic Sea using multiple satellite sensors. This appears to be one of the longest satellite-based time series in biological oceanography. The satellite algorithm is based on remote sensing reflectance of the water in the red band, a measure of turbidity. Validation of the satellite algorithm using horizontal transects from a ship of opportunity showed the strongest relationship with phycocyanin fluorescence (an indicator of cyanobacteria), followed by turbidity and then by chlorophyll a fluorescence. The areal fraction with cyanobacteria accumulations (FCA) and the total accumulated area affected (TA) were used to characterize the intensity and extent of the accumulations. The fraction with cyanobacteria accumulations was calculated as the ratio of the number of detected accumulations to the number of cloud-free sea-surface views per pixel during the season (July-August). The total accumulated area affected was calculated by adding the area of pixels where accumulations were detected at least once during the season. The fraction with cyanobacteria accumulations and TA were correlated (R2 = 0.55) and both showed large interannual and decadal-scale variations. The average FCA was significantly higher for the second half of the time series (13.8%, 1997-2013) than for the first half (8.6%, 1979-1996). However, that does not seem to represent a long-term trend but decadal-scale oscillations. Cyanobacteria accumulations were common in the 1970s and early 1980s (FCA between 11-17%), but rare (FCA below 4%) during 1985-1990; they increased again starting in 1991 and particularly in 1999, reaching maxima in FCA (~ 25

  11. Laser range profile of cones

    NASA Astrophysics Data System (ADS)

    Zhou, Wenzhen; Gong, Yanjun; Wang, Mingjun; Gong, Lei

    2016-10-01

    technology. Laser one-dimensional range profile can reflect the characteristics of the target shape and surface material. These techniques were motivated by applications of laser radar to target discrimination in ballistic missile defense. The radar equation of pulse laser about cone is given in this paper. This paper demonstrates the analytical model of laser one-dimensional range profile of cone based on the radar equation of the pulse laser. Simulations results of laser one-dimensional range profiles of some cones are given. Laser one-dimensional range profiles of cone, whose surface material with diffuse lambertian reflectance, is given in this paper. Laser one-dimensional range profiles of cone, whose surface mater with diffuse materials whose retroreflectance can be modeled closely with an exponential term that decays with increasing incidence angles, is given in this paper. Laser one-dimensional range profiles of different pulse width of cone is given in this paper. The influences of surface material, pulse width, attitude on the one-dimensional range are analyzed. The laser two-dimensional range profile is two-dimensional scattering imaging of pulse laser of target. The two-dimensional range profile of roughness target can provide range resolved information. An analytical model of two-dimensional laser range profile of cone is proposed. The simulations of two-dimensional laser range profiles of some cones are given. Laser two-dimensional range profiles of cone, whose surface mater with diffuse lambertian reflectance, is given in this paper. Laser two-dimensional range profiles of cone, whose surface mater with diffuse materials whose retroreflectance can be modeled closely with an exponential term that decays with increasing incidence angles, is given in this paper. The influence of pulse width, surface material on laser two-dimensional range profile is analyzed. Laser one-dimensional range profile and laser two-dimensional range profile are called as laser

  12. The Integrated Mode Management Interface

    NASA Technical Reports Server (NTRS)

    Hutchins, Edwin

    1996-01-01

    Mode management is the processes of understanding the character and consequences of autoflight modes, planning and selecting the engagement, disengagement and transitions between modes, and anticipating automatic mode transitions made by the autoflight system itself. The state of the art is represented by the latest designs produced by each of the major airframe manufacturers, the Boeing 747-400, the Boeing 777, the McDonnell Douglas MD-11, and the Airbus A320/A340 family of airplanes. In these airplanes autoflight modes are selected by manipulating switches on the control panel. The state of the autoflight system is displayed on the flight mode annunciators. The integrated mode management interface (IMMI) is a graphical interface to autoflight mode management systems for aircraft equipped with flight management computer systems (FMCS). The interface consists of a vertical mode manager and a lateral mode manager. Autoflight modes are depicted by icons on a graphical display. Mode selection is accomplished by touching (or mousing) the appropriate icon. The IMMI provides flight crews with an integrated interface to autoflight systems for aircraft equipped with flight management computer systems (FMCS). The current version is modeled on the Boeing glass-cockpit airplanes (747-400, 757/767). It runs on the SGI Indigo workstation. A working prototype of this graphics-based crew interface to the autoflight mode management tasks of glass cockpit airplanes has been installed in the Advanced Concepts Flight Simulator of the CSSRF of NASA Ames Research Center. This IMMI replaces the devices in FMCS equipped airplanes currently known as mode control panel (Boeing), flight guidance control panel (McDonnell Douglas), and flight control unit (Airbus). It also augments the functions of the flight mode annunciators. All glass cockpit airplanes are sufficiently similar that the IMMI could be tailored to the mode management system of any modern cockpit. The IMMI does not replace the

  13. Clinical issues of mucus accumulation in COPD

    PubMed Central

    Ramos, Frederick L; Krahnke, Jason S; Kim, Victor

    2014-01-01

    Airway mucus is part of the lung’s native immune function that traps particulates and microorganisms, enabling their clearance from the lung by ciliary transport and cough. Mucus hypersecretion and chronic productive cough are the features of the chronic bronchitis and chronic obstructive pulmonary disease (COPD). Overproduction and hypersecretion by goblet cells and the decreased elimination of mucus are the primary mechanisms responsible for excessive mucus in chronic bronchitis. Mucus accumulation in COPD patients affects several important outcomes such as lung function, health-related quality of life, COPD exacerbations, hospitalizations, and mortality. Nonpharmacologic options for the treatment of mucus accumulation in COPD are smoking cessation and physical measures used to promote mucus clearance. Pharmacologic therapies include expectorants, mucolytics, methylxanthines, beta-adrenergic receptor agonists, anticholinergics, glucocorticoids, phosphodiesterase-4 inhibitors, antioxidants, and antibiotics. PMID:24493923

  14. Accumulative Tritium Transfer from Water into Biosystems

    SciTech Connect

    Baumgaertner, Franz

    2005-07-15

    The energy balance of hydrogen isotopes in H bonds of water and biomolecules results in accumulative tritium transfer from water into biomolecules. Tests of DNA dissolved in tritiated water and of maize or barley hydroponically grown in tritiated water confirm the increase. The primary hydration shell of DNA shows an accumulation factor of {approx}1.4, and the exchangeable hydrogens inside DNA show {approx}2. Logistic growth analyses of maize and barley reveal the intrinsic growth rates of tritium 1.3 and 1.2 times larger than that of hydrogen. The higher rate of tritium than hydrogen incorporation in solid biomatter is caused by the hydration shells, which constitute an intrinsic component of biomolecules.

  15. Plaque accumulations caused by interdental stripping.

    PubMed

    Radlanski, R J; Jäger, A; Schwestka, R; Bertzbach, F

    1988-11-01

    Human enamel surfaces were stripped with orthodontic grinding and finishing materials, and evaluated with the scanning electron microscope (SEM). Even under in vitro conditions with the finest finishing strips, it was not possible to produce an enamel surface free of the furrows that result from the initial abrasion caused by the coarse strip. Enamel surfaces stripped gradually from coarse to superfine were left in the mouths of patients for 12 weeks and evaluated with the SEM. The edges of the furrows were found to be smoother but the furrows remained wide and deep enough to facilitate more plaque accumulations than those on untreated surfaces. The use of dental floss did not result in prevention of plaque accumulations along the bottom of the furrows.

  16. Heat accumulation during pulsed laser materials processing.

    PubMed

    Weber, Rudolf; Graf, Thomas; Berger, Peter; Onuseit, Volkher; Wiedenmann, Margit; Freitag, Christian; Feuer, Anne

    2014-05-05

    Laser materials processing with ultra-short pulses allows very precise and high quality results with a minimum extent of the thermally affected zone. However, with increasing average laser power and repetition rates the so-called heat accumulation effect becomes a considerable issue. The following discussion presents a comprehensive analytical treatment of multi-pulse processing and reveals the basic mechanisms of heat accumulation and its consequence for the resulting processing quality. The theoretical findings can explain the experimental results achieved when drilling microholes in CrNi-steel and for cutting of CFRP. As a consequence of the presented considerations, an estimate for the maximum applicable average power for ultra-shorts pulsed laser materials processing for a given pulse repetition rate is derived.

  17. Solar-Panel Dust Accumulation and Cleanings

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Air-fall dust accumulates on the solar panels of NASA's Mars Exploration Rovers, reducing the amount of sunlight reaching the solar arrays. Pre-launch models predicted steady dust accumulation. However, the rovers have been blessed with occasional wind events that clear significant amounts of dust from the solar panels.

    This graph shows the effects of those panel-cleaning events on the amount of electricity generated by Spirit's solar panels. The horizontal scale is the number of Martian days (sols) after Spirit's Jan. 4, 2005, (Universal Time) landing on Mars. The vertical scale indicates output from the rover's solar panels as a fraction of the amount produced when the clean panels first opened. Note that the gradual declines are interrupted by occasional sharp increases, such as a dust-cleaning event on sol 420.

  18. Higher order microfibre modes for dielectric particle trapping and propulsion.

    PubMed

    Maimaiti, Aili; Truong, Viet Giang; Sergides, Marios; Gusachenko, Ivan; Nic Chormaic, Síle

    2015-03-13

    Optical manipulation in the vicinity of optical micro- and nanofibres has shown potential across several fields in recent years, including microparticle control, and cold atom probing and trapping. To date, most work has focussed on the propagation of the fundamental mode through the fibre. However, along the maximum mode intensity axis, higher order modes have a longer evanescent field extension and larger field amplitude at the fibre waist compared to the fundamental mode, opening up new possibilities for optical manipulation and particle trapping. We demonstrate a microfibre/optical tweezers compact system for trapping and propelling dielectric particles based on the excitation of the first group of higher order modes at the fibre waist. Speed enhancement of polystyrene particle propulsion was observed for the higher order modes compared to the fundamental mode for particles ranging from 1 μm to 5 μm in diameter. The optical propelling velocity of a single, 3 μm polystyrene particle was found to be 8 times faster under the higher order mode than the fundamental mode field for a waist power of 25 mW. Experimental data are supported by theoretical calculations. This work can be extended to trapping and manipulation of laser-cooled atoms with potential for quantum networks.

  19. Higher order microfibre modes for dielectric particle trapping and propulsion

    PubMed Central

    Maimaiti, Aili; Truong, Viet Giang; Sergides, Marios; Gusachenko, Ivan; Nic Chormaic, Síle

    2015-01-01

    Optical manipulation in the vicinity of optical micro- and nanofibres has shown potential across several fields in recent years, including microparticle control, and cold atom probing and trapping. To date, most work has focussed on the propagation of the fundamental mode through the fibre. However, along the maximum mode intensity axis, higher order modes have a longer evanescent field extension and larger field amplitude at the fibre waist compared to the fundamental mode, opening up new possibilities for optical manipulation and particle trapping. We demonstrate a microfibre/optical tweezers compact system for trapping and propelling dielectric particles based on the excitation of the first group of higher order modes at the fibre waist. Speed enhancement of polystyrene particle propulsion was observed for the higher order modes compared to the fundamental mode for particles ranging from 1 μm to 5 μm in diameter. The optical propelling velocity of a single, 3 μm polystyrene particle was found to be 8 times faster under the higher order mode than the fundamental mode field for a waist power of 25 mW. Experimental data are supported by theoretical calculations. This work can be extended to trapping and manipulation of laser-cooled atoms with potential for quantum networks. PMID:25766925

  20. Optimization of few-mode-fiber based mode converter for mode division multiplexing transmission

    NASA Astrophysics Data System (ADS)

    Xie, Yiwei; Fu, Songnian; Zhang, Minming; Tang, M.; Shum, P.; Liu, Deming

    2013-10-01

    Few-mode-fiber (FMF) based mode division multiplexing (MDM) is a promising technique to further increase the transmission capacity of single mode fibers. We propose and numerically investigate a fiber-optical mode converter (MC) using long period gratings (LPGs) fabricated on the FMF by point-by-point CO2 laser inscription technique. In order to precisely excite three modes (LP01, LP11, and LP02), both untilted LPG and tilted LPG are comprehensively optimized through the length, index modulation depth, and tilt angle of the LPG in order to achieve a mode contrast ratio (MCR) of more than 20 dB with less wavelength dependence. It is found that the proposed MCs have obvious advantages of high MCR, low mode crosstalk, easy fabrication and maintenance, and compact size.