Science.gov

Sample records for adjacent channel power

  1. Adjacent channel interference degradation with minimum shift keyed modulation

    NASA Technical Reports Server (NTRS)

    Ziemer, R. E.

    1981-01-01

    Computer simulation results for degradation in signal-to-noise ratio for various values of bit error probability are given for minimum shift-keyed-type signaling in the presence of adjacent channel interference. A serial modulator structure which utilizes spectral shaping is characterized in terms of envelope deviation and bandwidth efficiency. This serial generation technique is convenient for implementation at high data rates and results in signal spectra with lower sidelobe levels than conventional minimum shift-keyed modulation at the expense of moderate envelope deviation. Because of the lower sidelobe levels, the resulting spectra allow denser channel packing than does ideal MSK.

  2. Quaternary geology of the Channeled Scabland and adjacent areas

    NASA Technical Reports Server (NTRS)

    Baker, V. R.

    1978-01-01

    The quaternary history of the channeled scabland is characterized by discrete episodes of catastrophic flooding and prolonged periods of loess accumulation and soil formation. The loess sequence was correlated with Richmond's Rocky Mountain glacial chronology. At least five major catastrophic flood events occurred in the general vicinity of the channeled scabland. The earliest episode occurred prior to the extensive deposition of the Palouse formation. The last major episode of flooding occurred between about 18,000 and 13,000 years ago. It probably consisted of two outbursts from glacial Lake Missoula.

  3. Fouling assemblages on offshore wind power plants and adjacent substrata

    NASA Astrophysics Data System (ADS)

    Wilhelmsson, Dan; Malm, Torleif

    2008-09-01

    A significant expansion of offshore wind power is expected in the near future, with thousands of turbines in coastal waters, and various aspects of how this may influence the coastal ecology including disturbance effects from noise, shadows, electromagnetic fields, and changed hydrological conditions are accordingly of concern. Further, wind power plants constitute habitats for a number of organisms, and may locally alter assemblage composition and biomass of invertebrates, algae and fish. In this study, fouling assemblages on offshore wind turbines were compared to adjacent hard substrate. Influences of the structures on the seabed were also investigated. The turbines differed significantly from adjacent boulders in terms of assemblage composition of epibiota and motile invertebrates. Species number and Shannon-Wiener diversity were, also, significantly lower on the wind power plants. It was also indicated that the turbines might have affected assemblages of invertebrates and algae on adjacent boulders. Off shore wind power plant offer atypical substrates for fouling assemblages in terms of orientation, depth range, structure, and surface texture. Some potential ecological implications of the addition of these non-natural habitats for coastal ecology are discussed.

  4. Cochannel and Adjacent-Channel Interference in Nonlinear Minimum-Shift-Keyed Satellite System

    NASA Technical Reports Server (NTRS)

    Yu, John

    1995-01-01

    The interference susceptibility of a serial-minimum-shift-keyed (SMSK) modulation system to an interfering signal transmitted through a satellite link with cascaded nonlinear elements was investigated through computer simulation. The satellite link evaluated in this study represented NASA's Advanced Communications Technology Satellite (ACTS) system. Specifically, nonlinear characteristics were used that had specified amplitude-modulation to amplitude-modulation and amplitude-modulation to phase-modulation transfer characteristics obtained from the actual ACTS hardware. Two measurement scenarios were analyzed: degradation of an MSK satellite link from cochannel interference and from adjacent-channel interference. Interference was evaluated in terms of the probability of bit error rate (BER) versus energy per bit over noise power density Eb/No.

  5. Uplink scheduling and adjacent-channel coupling loss analysis for TD-LTE deployment.

    PubMed

    Yeo, Woon-Young; Moon, Sung Ho; Kim, Jae-Hoon

    2014-01-01

    TD-LTE, one of the two duplexing modes in LTE, operates in unpaired spectrum and has the advantages of TDD-based technologies. It is expected that TD-LTE will be more rapidly deployed in near future and most of WiMax operators will upgrade their networks to TD-LTE gradually. Before completely upgrading to TD-LTE, WiMax may coexist with TD-LTE in an adjacent frequency band. In addition, multiple TD-LTE operators may deploy their networks in adjacent bands. When more than one TDD network operates in adjacent frequency bands, severe interference may happen due to adjacent channel interference (ACI) and unsynchronized operations. In this paper, coexistence issues between TD-LTE and other systems are analyzed and coexistence requirements are provided. This paper has three research objectives. First, frame synchronization between TD-LTE and WiMax is discussed by investigating possible combinations of TD-LTE and WiMax configurations. Second, an uplink scheduling algorithm is proposed to utilize a leakage pattern of ACI in synchronized operations. Third, minimum requirements for coexistence in unsynchronized operations are analyzed by introducing a concept of adjacent-channel coupling loss. From the analysis and simulation results, we can see that coexistence of TD-LTE with other TDD systems is feasible if the two networks are synchronized. For the unsynchronized case, some special cell-site engineering techniques may be required to reduce the ACI. PMID:24707214

  6. Uplink scheduling and adjacent-channel coupling loss analysis for TD-LTE deployment.

    PubMed

    Yeo, Woon-Young; Moon, Sung Ho; Kim, Jae-Hoon

    2014-01-01

    TD-LTE, one of the two duplexing modes in LTE, operates in unpaired spectrum and has the advantages of TDD-based technologies. It is expected that TD-LTE will be more rapidly deployed in near future and most of WiMax operators will upgrade their networks to TD-LTE gradually. Before completely upgrading to TD-LTE, WiMax may coexist with TD-LTE in an adjacent frequency band. In addition, multiple TD-LTE operators may deploy their networks in adjacent bands. When more than one TDD network operates in adjacent frequency bands, severe interference may happen due to adjacent channel interference (ACI) and unsynchronized operations. In this paper, coexistence issues between TD-LTE and other systems are analyzed and coexistence requirements are provided. This paper has three research objectives. First, frame synchronization between TD-LTE and WiMax is discussed by investigating possible combinations of TD-LTE and WiMax configurations. Second, an uplink scheduling algorithm is proposed to utilize a leakage pattern of ACI in synchronized operations. Third, minimum requirements for coexistence in unsynchronized operations are analyzed by introducing a concept of adjacent-channel coupling loss. From the analysis and simulation results, we can see that coexistence of TD-LTE with other TDD systems is feasible if the two networks are synchronized. For the unsynchronized case, some special cell-site engineering techniques may be required to reduce the ACI.

  7. Uplink Scheduling and Adjacent-Channel Coupling Loss Analysis for TD-LTE Deployment

    PubMed Central

    Yeo, Woon-Young; Moon, Sung Ho

    2014-01-01

    TD-LTE, one of the two duplexing modes in LTE, operates in unpaired spectrum and has the advantages of TDD-based technologies. It is expected that TD-LTE will be more rapidly deployed in near future and most of WiMax operators will upgrade their networks to TD-LTE gradually. Before completely upgrading to TD-LTE, WiMax may coexist with TD-LTE in an adjacent frequency band. In addition, multiple TD-LTE operators may deploy their networks in adjacent bands. When more than one TDD network operates in adjacent frequency bands, severe interference may happen due to adjacent channel interference (ACI) and unsynchronized operations. In this paper, coexistence issues between TD-LTE and other systems are analyzed and coexistence requirements are provided. This paper has three research objectives. First, frame synchronization between TD-LTE and WiMax is discussed by investigating possible combinations of TD-LTE and WiMax configurations. Second, an uplink scheduling algorithm is proposed to utilize a leakage pattern of ACI in synchronized operations. Third, minimum requirements for coexistence in unsynchronized operations are analyzed by introducing a concept of adjacent-channel coupling loss. From the analysis and simulation results, we can see that coexistence of TD-LTE with other TDD systems is feasible if the two networks are synchronized. For the unsynchronized case, some special cell-site engineering techniques may be required to reduce the ACI. PMID:24707214

  8. A study on the co- and adjacent channel protection requirements for mobile satellite ACSSB modulation

    NASA Technical Reports Server (NTRS)

    Sydor, John T.

    1988-01-01

    Samples of speech modulated by narrowband frequency modulation (NBFM) (cellular) and amplitude companded single sideband (ACSSB) radios were subjected to simulated co- and adjacent channel interference environments typical of proposed frequency division multiple access (FDMA) mobile satellite systems. These samples were then listened to by a group of evaluators whose subjective responses to the samples were used to produce a series of graphs showing the relationship between subjective acceptability, carrier to noise density (C/No), carrier to interference ratio (C/I), and frequency offset. The results show that in a mobile satellite environment, ACSSB deteriorates more slowly than NBFM. The co- and adjacent channel protection ratios for both modulation techniques were roughly the same, even though the mechanism for signal deterioration is different.

  9. Suppression of adjacent-channel and cochannel FM interference via extended Kalman filtering

    SciTech Connect

    Bradley, J.N.

    1991-11-01

    A method is discussed for the problem of demodulating an FM signal in the presence of an adjacent-channel or cochannel interferer. State-space descriptions of the underlying message processes and the measurement process are presented which are then incorporated in an extended Kalman filter framework. The extended filter was necessary due to the nonlinearity of the measurement equation. The results of computer simulations are presented which demonstrate the system performance for various selections of the modulation index and signal separation. The derived system is contrasted to the previous state of the art in this area which involved maximum likelihood estimation. 5 refs.

  10. Floodtide pulses after low tides in shallow subembayments adjacent to deep channels

    USGS Publications Warehouse

    Warner, J.C.; Schoellhamer, D.H.; Ruhl, C.A.; Burau, J.R.

    2004-01-01

    In shallow waters surface gravity waves (tides) propagate with a speed proportional to the square root of water depth (c = ???g(h+??)). As the ratio of free surface displacement to mean depth (??/h) approaches unity the wave will travel noticeably faster at high tide than at low tide, creating asymmetries in the tidal form. This physical process is explained analytically by the increased significance of friction and the nonlinear terms in the continuity and momentum equations. In a tidal system comprising a shallow bay adjacent to a deeper channel, tidal asymmetries will be more prevalent in the shallow bay. Thus strong barotropic gradients can be generated between the two, producing rapid accelerations of currents into the bay (relative to other bay tidal processes) and create a maximum peak in the flood tide that we describe as a floodtide pulse. These floodtide pulses can promote a landward flux of suspended-sediment into the bay. In Grizzly Bay (part of northern San Francisco Bay, USA), field observations verify the occurrence of floodtide pulses during the lowest low tides of the year. No pulses were observed in neighboring Honker Bay, which has an average depth ???30 cm greater than Grizzly Bay. Numerical simulations of northern San Francisco Bay using realistic bathymetry demonstrated that floodtide pulses occurred in Grizzly Bay but not in Honker Bay, consistent with the observations. Both observations and numerical simulations show that floodtide pulses promote a landward flux of sediment into Grizzly Bay. Numerical simulations of an idealized bay-channel system quantify the importance of mean depth and friction in creating these floodtide pulses. ?? 2004 Elsevier Ltd. All rights reserved.

  11. Cohering and decohering power of quantum channels

    NASA Astrophysics Data System (ADS)

    Mani, Azam; Karimipour, Vahid

    2015-09-01

    We introduce the concepts of cohering and decohering power of quantum channels. Using the axiomatic definition of the coherence measure, we show that the optimization required for calculations of these measures can be restricted to pure input states and hence greatly simplified. We then use two examples of this measure, one based on the skew information and the other based on the l1 norm; we find the cohering and decohering measures of a number of one-, two-, and n -qubit channels. Contrary to the view at first glance, it is seen that quantum channels can have cohering power. It is also shown that a specific property of a qubit unitary map is that it has equal cohering and decohering power in any basis. Finally, we derive simple relations between cohering and decohering powers of unitary qubit gates and their tensor products, results which have physically interesting implications.

  12. Geomorphic data collected within and adjacent to Nebraska Public Power District's Cottonwood Ranch Property, Platte River, Nebraska, Water Year 2001

    USGS Publications Warehouse

    Kinzel, Paul; Parker, Randolph; Nelson, Johnathan; Burman, R.; Heckman, Aashley

    2003-01-01

    River-channel topographic surveys were conducted and bed-material samples were collected along transects across the Platte River during water year 2001 (October 1, 2000 to September 30, 2001). A total of 57 transect lines or cross sections were established within three study reaches located along the middle channel of the Platte River in a 2,650-acre parcel of land owned by the Nebraska Public Power District (NPPD), hereinafter referred to as the Cottonwood Ranch Property. Five additional cross sections were established downstream of the Cottonwood Ranch Property across the entire width of the Platte River as a component of a proposed future general monitoring program. A development and enhancement plan is proposed by NPPD on the Cottonwood Ranch Property to satisfy their Federal Energy Regulatory Commission (FERC) relicensing guidelines. The goal of the plan is to improve habitat along this reach for endangered species. The United States Geological Survey (USGS) designed a monitoring and research program to study and detect what effects, if any, these channel management actions have on channel morphology and sediment transport within and adjacent to the Cottonwood Ranch Property. This report presents the data-collection methods and summarizes the geomorphic data collected in support of the monitoring program for water year 2001.

  13. Power module assemblies with staggered coolant channels

    DOEpatents

    Herron, Nicholas Hayden; Mann, Brooks S; Korich, Mark D

    2013-07-16

    A manifold is provided for supporting a power module assembly with a plurality of power modules. The manifold includes a first manifold section. The first face of the first manifold section is configured to receive the first power module, and the second face of the first manifold section defines a first cavity with a first baseplate thermally coupled to the first power module. The first face of the second manifold section is configured to receive the second power module, and the second face of the second manifold section defines a second cavity with a second baseplate thermally coupled to the second power module. The second face of the first manifold section and the second face of the second manifold section are coupled together such that the first cavity and the second cavity form a coolant channel. The first cavity is at least partially staggered with respect to second cavity.

  14. Adjacency Matrix-Based Transmit Power Allocation Strategies in Wireless Sensor Networks

    PubMed Central

    Consolini, Luca; Medagliani, Paolo; Ferrari, Gianluigi

    2009-01-01

    In this paper, we present an innovative transmit power control scheme, based on optimization theory, for wireless sensor networks (WSNs) which use carrier sense multiple access (CSMA) with collision avoidance (CA) as medium access control (MAC) protocol. In particular, we focus on schemes where several remote nodes send data directly to a common access point (AP). Under the assumption of finite overall network transmit power and low traffic load, we derive the optimal transmit power allocation strategy that minimizes the packet error rate (PER) at the AP. This approach is based on modeling the CSMA/CA MAC protocol through a finite state machine and takes into account the network adjacency matrix, depending on the transmit power distribution and determining the network connectivity. It will be then shown that the transmit power allocation problem reduces to a convex constrained minimization problem. Our results show that, under the assumption of low traffic load, the power allocation strategy, which guarantees minimal delay, requires the maximization of network connectivity, which can be equivalently interpreted as the maximization of the number of non-zero entries of the adjacency matrix. The obtained theoretical results are confirmed by simulations for unslotted Zigbee WSNs. PMID:22346705

  15. 47 CFR 73.810 - Third adjacent channel complaint and license modification procedure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... the reception of the signal of a full power station to such affected full power station. (b) A full power station shall review all complaints it receives, either directly or indirectly, from listeners regarding alleged interference caused by the operations of an LPFM station. Such full power station...

  16. A low power Multi-Channel Analyzer

    SciTech Connect

    Anderson, G.A.; Brackenbush, L.W.

    1993-06-01

    The instrumentation used in nuclear spectroscopy is generally large, is not portable, and requires a lot of power. Key components of these counting systems are the computer and the Multi-Channel Analyzer (MCA). To assist in performing measurements requiring portable systems, a small, very low power MCA has been developed at Pacific Northwest Laboratory (PNL). This MCA is interfaced with a Hewlett Packard palm top computer for portable applications. The MCA can also be connected to an IBM/PC for data storage and analysis. In addition, a real-time time display mode allows the user to view the spectra as they are collected.

  17. 47 CFR 73.810 - Third adjacent channel complaint and license modification procedure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... located within the predicted 60 dBu contour of the affected full power station as such contour existed as... located within the 60 dBu contour of the affected full power station and not more than one kilometer...

  18. Tracing sources of organic matter in adjacent urban streams having different degrees of channel modification.

    PubMed

    Duan, Shuiwang; Amon, Rainer M W; Brinkmeyer, Robin L

    2014-07-01

    Urbanization and stream-channel modifications affect organic matter concentrations and quality in streams, by altering allochthonous organic matter input and in-stream transformation. This study uses multiple tracers (δ(13)C, δ(15)N, C/N ratio, and chlorophyll-a) to track sources of organic matter in two highly urbanized bayous in Houston (Texas, USA). Wastewater treatment plants (WWTPs) are located in headwaters of both bayous and contribute more than 75% to water flow. Low isotopic relatedness to natural end-members and enriched δ(15)N values suggest the influence of WWTPs on the composition of all organic matter fractions. The two bayous differ in degree of channel improvement resulting in different responses to hydrological conditions. During high flow conditions, the influence of terrestrial organic matter and sediment resuspension was much more pronounced in the Buffalo Bayou than in the concrete-lined White Oak Bayou. Particulate organic matter (POM) in White Oak Bayou had similar values of enriched δ(15)N in all subsegments, whereas in Buffalo Bayou, the degree of δ(15)N enrichment was less in the subsegments of the lower watershed. The difference in riparian zone contributions and interactions with sediments/soils was likely responsible for the compositional differences between the two bayous. Phytoplankton inputs were significantly higher in the bayous, especially in slow-flowing sections, relative to the reference sites, and elevated phytoplankton inputs accounted for the observed stable C isotope differences between FPOM and high molecular weight dissolved organic matter (HMW DOM). Relative to POM, HMW DOM in the bayous was similar to WWTP effluents and showed minor longitudinal variability in both streams suggesting that WWTPs contribute much of the DOM in the systems. Urbanization has a major influence on organic matter sources and quality in these urban water bodies and these changes seem further enhanced by stream channel modifications.

  19. The influence of paleo currents upon the Santaren Channel and the adjacent carbonate platforms, Bahamas.

    NASA Astrophysics Data System (ADS)

    Paulat, Marco; Lüdmann, Thomas; Betzler, Christian; Eberli, Gregor; Lindhorst, Sebastian

    2015-04-01

    The closure of the Central American Seaway and the reorganization of the ocean currents had a global impact on earth's climate. The sedimentation of the Great Bahama Bank (GBB) and the smaller Cay Sal Bank (CSB) are influenced by the Atlantic North Equatorial Current and the Florida Current. New high-resolution multichannel seismic data sets tied to the IODP leg 166 wells document that the shape of Bahama Banks and the sedimentation processes in the Santaren Channel (SC) between GBB and CSB are strongly related to changes in the strength of these currents. Since the Upper Miocene, the SC is filled up by a huge package of drift sediments, namely the Santaren Drift (SD). The buildup of the SD causes a local high in the recent bathymetry perpendicular to the surrounding steep platform slopes. The SD shows a typical mounded morphology and progrades northwards in direction of the Florida Channel. The SD was established during the late Miocene. Seismic facies and internal configuration indicate an environment of a stable north flowing current with a major depocenter related to the center of the SC. Additionally, a second depocenter at the central eastern flank of CSB established and preserved till early Pleistocene when the slope sedimentation starts to dominate. This depocenter points to a strengthened countercurrent component in the eastern SC. From the lower Pliocene to the upper Pleistocene the volume of the SD expanded, associated with an intensification of the current in the SC along its eastern flank, indicated by deep erosional channels parallel to the margin of GBB in the northern part of the survey area. This trend probably was initiated as a consequence of current reorganization due to the final closure of the Central American Seaway. Lower slope sediments from GBB are eroded or only minor parts are preserved from lower Pliocene to upper Pleistocene. With late Pliocene falling sea-level, gravitational slope sedimentation from GBB into the SC increased with

  20. Controls on bacterial gas accumulations in thick Tertiary coal beds and adjacent channel sandstones, Powder River basin, Wyoming and Montana

    SciTech Connect

    Rice, D.D.; Flores, R.M. )

    1991-03-01

    Coal beds, as much as 250 ft thick, and adjacent sandstones in the Paleocene Tongue River Member of the Fort Union Formation are reservoirs for coal-derived natural gas in the Powder River basin. The discontinuous coal beds were deposited in raised, ombrotrophic peat bogs about 3 mi{sup 2} in size, adjoining networks of fluvial channels infilled by sand. Coal-bed thickness was controlled by basin subsidence and depositional environments. The average maceral composition of the coals is 88% huminite (vitrinite), 5% liptinite, and 7% inertinite. The coals vary in rank from subbituminous C to A (R{sub o} values of 0.4 to 0.5%). Although the coals are relatively low rank, they display fracture systems. Natural gas desorbed and produced from the coal beds and adjacent sandstones is composed mainly of methane with lesser amount of Co{sub 2} ({lt}10%). The methane is isotopically light and enriched in deuterium. The gases are interpreted to be generated by bacterial processes and the fermentation pathway, prior to the main phase of thermogenic methane generation by devolatilization. Large amounts of bicarbonate water generated during early stages of coalification will have to be removed from the fracture porosity in the coal beds before desorption and commercial gas production can take place. Desorbed amounts of methane-rich, bacterial gas in the Powder River basin are relatively low ({lt}60 Scf/ton) compared to amounts of thermogenic coal-bed gases (hundreds of Scf/ton) from other Rocky Mountain basins. However, the total coal-bed gas resource in both the coal beds and the adjacent sandstones is considered to be large (as much as 40 Tcf) because of the vast coal resources (as much as 1.3 trillion tons).

  1. Power distribution in two-dimensional optical network channels

    NASA Astrophysics Data System (ADS)

    Wang, Dong-Xue; Karim, Mohammad A.

    1996-04-01

    The power distribution in two-dimensional optical network channels is analyzed. The maximum number of allowable channels as determined by the characteristics of optical detector is identified, in particular, for neural-network and wavelet-transform applications.

  2. Statistical power to detect change in a mangrove shoreline fish community adjacent to a nuclear power plant.

    PubMed

    Dolan, T E; Lynch, P D; Karazsia, J L; Serafy, J E

    2016-03-01

    An expansion is underway of a nuclear power plant on the shoreline of Biscayne Bay, Florida, USA. While the precise effects of its construction and operation are unknown, impacts on surrounding marine habitats and biota are considered by experts to be likely. The objective of the present study was to determine the adequacy of an ongoing monitoring survey of fish communities associated with mangrove habitats directly adjacent to the power plant to detect fish community changes, should they occur, at three spatial scales. Using seasonally resolved data recorded during 532 fish surveys over an 8-year period, power analyses were performed for four mangrove fish metrics (fish diversity, fish density, and the occurrence of two ecologically important fish species: gray snapper (Lutjanus griseus) and goldspotted killifish (Floridichthys carpio). Results indicated that the monitoring program at current sampling intensity allows for detection of <33% changes in fish density and diversity metrics in both the wet and the dry season in the two larger study areas. Sampling effort was found to be insufficient in either season to detect changes at this level (<33%) in species-specific occurrence metrics for the two fish species examined. The option of supplementing ongoing, biological monitoring programs for improved, focused change detection deserves consideration from both ecological and cost-benefit perspectives. PMID:26903208

  3. Statistical power to detect change in a mangrove shoreline fish community adjacent to a nuclear power plant.

    PubMed

    Dolan, T E; Lynch, P D; Karazsia, J L; Serafy, J E

    2016-03-01

    An expansion is underway of a nuclear power plant on the shoreline of Biscayne Bay, Florida, USA. While the precise effects of its construction and operation are unknown, impacts on surrounding marine habitats and biota are considered by experts to be likely. The objective of the present study was to determine the adequacy of an ongoing monitoring survey of fish communities associated with mangrove habitats directly adjacent to the power plant to detect fish community changes, should they occur, at three spatial scales. Using seasonally resolved data recorded during 532 fish surveys over an 8-year period, power analyses were performed for four mangrove fish metrics (fish diversity, fish density, and the occurrence of two ecologically important fish species: gray snapper (Lutjanus griseus) and goldspotted killifish (Floridichthys carpio). Results indicated that the monitoring program at current sampling intensity allows for detection of <33% changes in fish density and diversity metrics in both the wet and the dry season in the two larger study areas. Sampling effort was found to be insufficient in either season to detect changes at this level (<33%) in species-specific occurrence metrics for the two fish species examined. The option of supplementing ongoing, biological monitoring programs for improved, focused change detection deserves consideration from both ecological and cost-benefit perspectives.

  4. Flocculation on a muddy intertidal flat in Willapa Bay, Washington, Part II: Observations of suspended particle size in a secondary channel and adjacent flat

    NASA Astrophysics Data System (ADS)

    Hill, P. S.; Newgard, J. P.; Law, B. A.; Milligan, T. G.

    2013-06-01

    During the last week of February and first week of March in 2010, instruments for measuring current speed and suspended particle size and concentration were placed in a secondary channel and on an adjacent intertidal mudflat at the southern end of Willapa Bay on the Pacific coast of Washington State. Observations show that during spring tides, flood-tide velocity pulses occurred in the channel as water rose above the level of the banks. These pulses resuspended flocs from the channel and advected them over the adjacent flat. During transport, there was some evidence of aggregation of resuspended flocs into larger flocs. As current speeds decreased after the flood pulses, flocs that had advected over the flat deposited quickly. Freshly deposited flocs were resuspended as water levels fell over the flat, with suspended concentrations peaking as water from the flat drained back into the channel. Flocs returning to the channel deposited as currents waned after the ebb pulse. In the channel, the more energetic ebb pulses were strong enough to cause floc breakup. Resuspension and transport of flocs were reduced significantly during neap tides. During periods with high winds, seabed stresses generated by waves limited the deposition of flocs on the seabed. These observations indicate that the floors and flanks of secondary channels as well as the flats surrounding them are the sites of floc deposition and, therefore, are the most likely locations for low-strength, high-water-content muds that contain large fractions of silt and clay. The observations also provide a mechanistic explanation for why deposition rates are typically observed to be reduced at higher elevations on tidal flats and on areas of the flats remote from secondary channels.

  5. Evaluation of Dynamic Channel and Power Assignment for Cognitive Networks

    SciTech Connect

    Syed A. Ahmad; Umesh Shukla; Ryan E. Irwin; Luiz A. DaSilva; Allen B. MacKenzie

    2011-03-01

    In this paper, we develop a unifying optimization formulation to describe the Dynamic Channel and Power Assignment (DCPA) problem and evaluation method for comparing DCPA algorithms. DCPA refers to the allocation of transmit power and frequency channels to links in a cognitive network so as to maximize the total number of feasible links while minimizing the aggregate transmit power. We apply our evaluation method to five algorithms representative of DCPA used in literature. This comparison illustrates the tradeoffs between control modes (centralized versus distributed) and channel/power assignment techniques. We estimate the complexity of each algorithm. Through simulations, we evaluate the effectiveness of the algorithms in achieving feasible link allocations in the network, as well as their power efficiency. Our results indicate that, when few channels are available, the effectiveness of all algorithms is comparable and thus the one with smallest complexity should be selected. The Least Interfering Channel and Iterative Power Assignment (LICIPA) algorithm does not require cross-link gain information, has the overall lowest run time, and highest feasibility ratio of all the distributed algorithms; however, this comes at a cost of higher average power per link.

  6. Power formula for open-channel flow resistance

    USGS Publications Warehouse

    Chen, Cheng-lung

    1988-01-01

    This paper evaluates various power formulas for flow resistance in open channels. Unlike the logarithmic resistance equation that can be theoretically derived either from Prandtl's mixing-length hypothesis or von Karman's similarity hypothesis, the power formula has long had an appearance of empiricism. Nevertheless, the simplicity in the form of the power formula has made it popular among the many possible forms of flow resistance formulas. This paper reexamines the concept and rationale of the power formulation, thereby addressing some critical issues in the modeling of flow resistance.

  7. Economic analyses of alpha channeling in tokamak power plants.

    SciTech Connect

    Ehst, D.A.

    1998-09-17

    The hot-ion-mode of operation [1] has long been thought to offer optimized performance for long-pulse or steady-state magnetic fusion power plants. This concept was revived in recent years when theoretical considerations suggested that nonthermal fusion alpha particles could be made to channel their power density preferentially to the fuel ions [2,3]. This so-called anomalous alpha particle slowing down can create plasmas with fuel ion temperate T{sub i} somewhat larger than the electron temperature T{sub e}, which puts more of the beta-limited plasma pressure into the useful fuel species (rather than non-reacting electrons). As we show here, this perceived benefit may be negligible or nonexistent for tokamaks with steady state current drive. It has likewise been argued [2,3] that alpha channeling could be arranged such that little or no external power would be needed to generate the steady state toroidal current. Under optimistic assumptions we show that such alpha-channeling current drive would moderately improve the economic performance of a first stability tokamak like ARIES-I [4], however a reversed-shear (advanced equilibrium) tokamak would likely not benefit since traditional radio-wave (rf) electron-heating current drive power would already be quite small.

  8. Estimates of maximum trappable ion beam power in plasma channels

    NASA Astrophysics Data System (ADS)

    Watrous, J. J.; Olson, R. E.

    Conservation laws and solutions to the equations of motion for single particles have been used to obtained greatest lower bounds on the ion beam power that can be injected into and confined within plasma channels. These bounds are use in the evaluation of proposed light ion driven ICF experiments and reactor concepts. Simple estimates of trappable power based on conservation laws will be compared with estimates based on solutions to the equation of motion. Consequences of the results of these calculations to current design studies will be discussed.

  9. Channeling power across ecological systems: social regularities in community organizing.

    PubMed

    Christens, Brian D; Inzeo, Paula Tran; Faust, Victoria

    2014-06-01

    Relational and social network perspectives provide opportunities for more holistic conceptualizations of phenomena of interest in community psychology, including power and empowerment. In this article, we apply these tools to build on multilevel frameworks of empowerment by proposing that networks of relationships between individuals constitute the connective spaces between ecological systems. Drawing on an example of a model for grassroots community organizing practiced by WISDOM—a statewide federation supporting local community organizing initiatives in Wisconsin—we identify social regularities (i.e., relational and temporal patterns) that promote empowerment and the development and exercise of social power through building and altering relational ties. Through an emphasis on listening-focused one-to-one meetings, reflection, and social analysis, WISDOM organizing initiatives construct and reinforce social regularities that develop social power in the organizing initiatives and advance psychological empowerment among participant leaders in organizing. These patterns are established by organizationally driven brokerage and mobilization of interpersonal ties, some of which span ecological systems.Hence, elements of these power-focused social regularities can be conceptualized as cross-system channels through which micro-level empowerment processes feed into macro-level exercise of social power, and vice versa. We describe examples of these channels in action, and offer recommendations for theory and design of future action research [corrected] .

  10. Eelgrass Meadows in the California Channel Islands and Adjacent Coast Reveal a Mosaic of Two Species, Evidence for Introgression and Variable Clonality

    PubMed Central

    Coyer, J. A.; Miller, K. A.; Engle, J. M.; Veldsink, J.; Cabello-Pasini, A.; Stam, W. T.; Olsen, J. L.

    2008-01-01

    Background and Aims Seagrasses are important facilitator species in shallow, soft-bottom marine environments worldwide and, in many places, are threatened by coastal development and eutrophication. One narrow-leaved species (Zostera marina) and one wide-leaved species, variously designated as Z. marina, Z. pacifica or Z. asiatica, are found off the California Channel Islands and adjacent California–Mexico coast. The aim of the present study was to confirm species identification genetically and to link patterns of genetic diversity, connectivity and hybridization among and within the populations with historical sea levels (Ice Age) or the contemporary environment. Methods Samples (n = 11–100) were collected from 28 sites off five California Channel Islands and six sites off the adjacent coast of southern California and Baja California, Mexico. DNA polymorphisms of the rDNA-ITS (internal transcribed spacer) cistron (nuclear), the matK intron (chloroplast) and nine microsatellite loci (nuclear) were examined in a population genetic and phylogeographic context. Key Results All wide-leaved individuals were Z. pacifica, whereas narrow-leaved forms were Z. marina. Microsatellite genotypes were consistent with hybridization between the two species in three populations. The present distribution of Z. pacifica follows a glacial age land mass rather than present oceanographic regimes, but no link was observed between the present distribution of Z. marina and past or present environments. Island populations of Z. marina often were clonal and characterized by low genotypic diversity compared with populations along the Baja California coast. The high level of clonal connectivity around Santa Catalina Island indicated the importance of dispersal and subsequent re-establishment of vegetative fragments. Conclusions The pristine environmental conditions of offshore islands do not guarantee maximum genetic diversity. Future restoration and transplantation efforts of seagrasses

  11. Power take-off analysis for diagonally connected MHD channels

    SciTech Connect

    Pan, Y C; Doss, E D

    1980-01-01

    The electrical loading of the power take-off region of diagonally connected MHD channels is investigated by a two-dimensional model. The study examines the loading schemes typical of those proposed for the U-25 and U-25 Bypass channels. The model is applicable for the following four cases: (1) connection with diodes only, (2) connection with diodes and equal resistors, (3) connection with diodes and variable resistances to obtain a given current distribution, and (4) connection with diodes and variable resistors under changing load. The analysis is applicable for the power take-off regions of single or multiple-output systems. The general behaviors of the current and the potential distributions in all four cases are discussed. The analytical results are in good agreement with the experimental data. It is found possible to design the electrical circuit of the channel in the take-off region so as to achieve a fairly even load current output under changing total load current.

  12. MHD channel performance for potential early commercial MHD power plants

    NASA Technical Reports Server (NTRS)

    Swallom, D. W.

    1981-01-01

    The commercial viability of full and part load early commercial MHD power plants is examined. The load conditions comprise a mass flow of 472 kg/sec in the channel, Rosebud coal, 34% by volume oxygen in the oxidizer preheated to 922 K, and a one percent by mass seeding with K. The full load condition is discussed in terms of a combined cycle plant with optimized electrical output by the MHD channel. Various electrical load parameters, pressure ratios, and magnetic field profiles are considered for a baseload MHD generator, with a finding that a decelerating flow rate yields slightly higher electrical output than a constant flow rate. Nominal and part load conditions are explored, with a reduced gas mass flow rate and an enriched oxygen content. An enthalpy extraction of 24.6% and an isentropic efficiency of 74.2% is predicted for nominal operation of a 526 MWe MHD generator, with higher efficiencies for part load operation.

  13. A low-power, wireless, 8-channel EEG monitoring headset.

    PubMed

    Brown, Lindsay; van de Molengraft, Jef; Yazicioglu, Refet Firat; Torfs, Tom; Penders, Julien; Van Hoof, Chris

    2010-01-01

    Micro- and nano-technology has enabled development of smaller and smarter wearable devices for medical and lifestyle related applications. In particular, recent advances in EEG monitoring technologies pave the way for wearable, wireless EEG monitoring devices. Here, a low-power wireless EEG sensor platform that measures 8-channels of EEG, is described. The platform is integrated into a wearable headset for ambulatory monitoring of EEG. While using standard EEG electrodes without conductive gel, a first evaluation shows the wireless headset is comparable to the reference system when looking at alpha wave discrimination. This device combines low-noise, and low-power functionality into an easy-to-use wireless headset, providing a first step towards a fully integrated, fully functional wearable wireless EEG monitoring system.

  14. Tunable multi-channel terahertz wave power splitter

    NASA Astrophysics Data System (ADS)

    Jiu-Sheng, Li; Han, Liu; Le, Zhang

    2015-12-01

    The combination of terahertz technology and photonic crystal provides a new approach to realize compact terahertz wave devices. Relying on a conventional photonic crystal waveguide and photonic crystal surface-mode waveguides, a tunable multi-channel terahertz-wave power splitter is proposed. The mechanism of such a power splitter is further theoretically analyzed and numerically investigated with the aid of the plane-wave-expansion method and the finite-difference time-domain method. With an appropriate design, the proposed device can split the input terahertz wave energy equally into six output ports at the frequency of 0.6 THz. When changing the external magnetic field, the input terahertz wave can be equally divided into four output ports with the aid of a magnetic-sensitive material. Furthermore, the present device is very compact and the total size is of 4.4×6.0 mm2.

  15. Micro-channel-based high specific power lithium target

    NASA Astrophysics Data System (ADS)

    Mastinu, P.; Martın-Hernández, G.; Praena, J.; Gramegna, F.; Prete, G.; Agostini, P.; Aiello, A.; Phoenix, B.

    2016-11-01

    A micro-channel-based heat sink has been produced and tested. The device has been developed to be used as a Lithium target for the LENOS (Legnaro Neutron Source) facility and for the production of radioisotope. Nevertheless, applications of such device can span on many areas: cooling of electronic devices, diode laser array, automotive applications etc. The target has been tested using a proton beam of 2.8MeV energy and delivering total power shots from 100W to 1500W with beam spots varying from 5mm2 to 19mm2. Since the target has been designed to be used with a thin deposit of lithium and since lithium is a low-melting-point material, we have measured that, for such application, a specific power of about 3kW/cm2 can be delivered to the target, keeping the maximum surface temperature not exceeding 150° C.

  16. Radioecology of Vertebrate Animals in the Area Adjacent to the Chernobyl Nuclear Power Plant Site in 1986-2008

    NASA Astrophysics Data System (ADS)

    Farfan, E. B.; Gashchak, S. P.; Makliuk, Y. A.; Maksymenko, A. M.; Bondarkov, M. D.; Jannik, G. T.; Marra, J. C.

    2009-12-01

    A widespread environmental contamination of the areas adjacent to the Chernobyl Nuclear Power Plant (ChNPP) site attracted a great deal of publicity to the biological consequences of the ChNPP catastrophe. However, only a few studies focused on a detailed analysis of radioactive contamination of the local wild fauna and most of them were published in Eastern European languages, making them poorly accessible for Western scientists. In addition, evaluation of this information appears difficult due to significant differences in raw data acquisition and analysis methodologies and final data presentation formats. Using an integrated approach to assessment of all available information, the International Radioecology Laboratory scientists showed that the ChNPP accident had increased the average values of the animals 137Cs and 90Sr contamination by a factor of thousands, followed by its decrease by a factor of tens, primarily resulting from a decrease in the biological accessibility of the radionuclides. However, this trend depended on many factors. Plant and bottom feeding fish species were the first to reach the maximum contamination levels. No data are available on other vertebrates, but it can be assumed that the same trend was true for all plant feeding animals and animals searching for food on the soil surface. The most significant decrease of the average values occurred during the first 3-5 years after the accident and it was the most pronounced for elks and plant and plankton feeding fish. Their diet included elements “alienated” from the major radionuclide inventory; for example, upper soil layers and bottom deposits where the fallout that had originally precipitated on plants, water and soils gradually migrated. Further radionuclide penetration into deeper layers of soils and its bonding with their mineral components intensified decontamination of the fauna. It took a while for the contamination of predatory fish and mammals (wolves) to reach the maximum

  17. A Beacon Transmission Power Control Algorithm Based on Wireless Channel Load Forecasting in VANETs.

    PubMed

    Mo, Yuanfu; Yu, Dexin; Song, Jun; Zheng, Kun; Guo, Yajuan

    2015-01-01

    In a vehicular ad hoc network (VANET), the periodic exchange of single-hop status information broadcasts (beacon frames) produces channel loading, which causes channel congestion and induces information conflict problems. To guarantee fairness in beacon transmissions from each node and maximum network connectivity, adjustment of the beacon transmission power is an effective method for reducing and preventing channel congestion. In this study, the primary factors that influence wireless channel loading are selected to construct the KF-BCLF, which is a channel load forecasting algorithm based on a recursive Kalman filter and employs multiple regression equation. By pre-adjusting the transmission power based on the forecasted channel load, the channel load was kept within a predefined range; therefore, channel congestion was prevented. Based on this method, the CLF-BTPC, which is a transmission power control algorithm, is proposed. To verify KF-BCLF algorithm, a traffic survey method that involved the collection of floating car data along a major traffic road in Changchun City is employed. By comparing this forecast with the measured channel loads, the proposed KF-BCLF algorithm was proven to be effective. In addition, the CLF-BTPC algorithm is verified by simulating a section of eight-lane highway and a signal-controlled urban intersection. The results of the two verification process indicate that this distributed CLF-BTPC algorithm can effectively control channel load, prevent channel congestion, and enhance the stability and robustness of wireless beacon transmission in a vehicular network.

  18. A Beacon Transmission Power Control Algorithm Based on Wireless Channel Load Forecasting in VANETs.

    PubMed

    Mo, Yuanfu; Yu, Dexin; Song, Jun; Zheng, Kun; Guo, Yajuan

    2015-01-01

    In a vehicular ad hoc network (VANET), the periodic exchange of single-hop status information broadcasts (beacon frames) produces channel loading, which causes channel congestion and induces information conflict problems. To guarantee fairness in beacon transmissions from each node and maximum network connectivity, adjustment of the beacon transmission power is an effective method for reducing and preventing channel congestion. In this study, the primary factors that influence wireless channel loading are selected to construct the KF-BCLF, which is a channel load forecasting algorithm based on a recursive Kalman filter and employs multiple regression equation. By pre-adjusting the transmission power based on the forecasted channel load, the channel load was kept within a predefined range; therefore, channel congestion was prevented. Based on this method, the CLF-BTPC, which is a transmission power control algorithm, is proposed. To verify KF-BCLF algorithm, a traffic survey method that involved the collection of floating car data along a major traffic road in Changchun City is employed. By comparing this forecast with the measured channel loads, the proposed KF-BCLF algorithm was proven to be effective. In addition, the CLF-BTPC algorithm is verified by simulating a section of eight-lane highway and a signal-controlled urban intersection. The results of the two verification process indicate that this distributed CLF-BTPC algorithm can effectively control channel load, prevent channel congestion, and enhance the stability and robustness of wireless beacon transmission in a vehicular network. PMID:26571042

  19. A Beacon Transmission Power Control Algorithm Based on Wireless Channel Load Forecasting in VANETs

    PubMed Central

    Mo, Yuanfu; Yu, Dexin; Song, Jun; Zheng, Kun; Guo, Yajuan

    2015-01-01

    In a vehicular ad hoc network (VANET), the periodic exchange of single-hop status information broadcasts (beacon frames) produces channel loading, which causes channel congestion and induces information conflict problems. To guarantee fairness in beacon transmissions from each node and maximum network connectivity, adjustment of the beacon transmission power is an effective method for reducing and preventing channel congestion. In this study, the primary factors that influence wireless channel loading are selected to construct the KF-BCLF, which is a channel load forecasting algorithm based on a recursive Kalman filter and employs multiple regression equation. By pre-adjusting the transmission power based on the forecasted channel load, the channel load was kept within a predefined range; therefore, channel congestion was prevented. Based on this method, the CLF-BTPC, which is a transmission power control algorithm, is proposed. To verify KF-BCLF algorithm, a traffic survey method that involved the collection of floating car data along a major traffic road in Changchun City is employed. By comparing this forecast with the measured channel loads, the proposed KF-BCLF algorithm was proven to be effective. In addition, the CLF-BTPC algorithm is verified by simulating a section of eight-lane highway and a signal-controlled urban intersection. The results of the two verification process indicate that this distributed CLF-BTPC algorithm can effectively control channel load, prevent channel congestion, and enhance the stability and robustness of wireless beacon transmission in a vehicular network. PMID:26571042

  20. Creation of the relevant next: How living systems capture the power of the adjacent possible through sign use.

    PubMed

    Favareau, Donald F

    2015-12-01

    Stuart Kauffman's revolutionary notion of the Adjacent Possible as an organizing principle in nature shares much in common with logician Charles S. Peirce's understanding of the universe as an ever-unfolding 'process ontology' of possibility space that is brought about through the recursive interaction of genuine possibility, transiently actualized order, and emergent (but never fully deterministic) lawfulness. Proceeding from these three fundamental categories of becoming-as-being, Peirce developed a complimentary logic of sign relations that, along with Estonian biologist Jakob von Uexküll's action-as-meaning-imprinting Umwelt theory, informs the work that is currently being undertaken under the aegis of Biosemiotics. In this paper, I will highlight the deep affinities between Kauffman's notion of the Adjacent Possible and Biosemiotics' hybrid Peircean/Uexküllian "sign" concept, by which living systems - both as individuals and in the aggregate (i.e., as co-actors, communities and lineages) - "capture" relevant aspects of their relations with the immediately given Adjacent Possible and preserve those recipes for future interaction possibilities as biologically instantiated signs. By so doing, living systems move into the Adjacent Possible by "collapsing the wave function" of possibility not just probabilistically, but guided by system-internal values arising from previously captured sign relations that are biologically instantiated as replicable system biases and generative constraints. The influence of such valenced and end-directed action in the world introduces into the universe the phenomenon of the Relevant (and not just deterministic, or even stochastic) Next. My argument in this paper is that organisms live out their lives perpetually confronted with negotiating the omnipresent Relevant Next, and are informed by the biological capture of their (and their lineage's) previous engagements in doing so. And because that "capture" of previous agent

  1. Creation of the relevant next: How living systems capture the power of the adjacent possible through sign use.

    PubMed

    Favareau, Donald F

    2015-12-01

    Stuart Kauffman's revolutionary notion of the Adjacent Possible as an organizing principle in nature shares much in common with logician Charles S. Peirce's understanding of the universe as an ever-unfolding 'process ontology' of possibility space that is brought about through the recursive interaction of genuine possibility, transiently actualized order, and emergent (but never fully deterministic) lawfulness. Proceeding from these three fundamental categories of becoming-as-being, Peirce developed a complimentary logic of sign relations that, along with Estonian biologist Jakob von Uexküll's action-as-meaning-imprinting Umwelt theory, informs the work that is currently being undertaken under the aegis of Biosemiotics. In this paper, I will highlight the deep affinities between Kauffman's notion of the Adjacent Possible and Biosemiotics' hybrid Peircean/Uexküllian "sign" concept, by which living systems - both as individuals and in the aggregate (i.e., as co-actors, communities and lineages) - "capture" relevant aspects of their relations with the immediately given Adjacent Possible and preserve those recipes for future interaction possibilities as biologically instantiated signs. By so doing, living systems move into the Adjacent Possible by "collapsing the wave function" of possibility not just probabilistically, but guided by system-internal values arising from previously captured sign relations that are biologically instantiated as replicable system biases and generative constraints. The influence of such valenced and end-directed action in the world introduces into the universe the phenomenon of the Relevant (and not just deterministic, or even stochastic) Next. My argument in this paper is that organisms live out their lives perpetually confronted with negotiating the omnipresent Relevant Next, and are informed by the biological capture of their (and their lineage's) previous engagements in doing so. And because that "capture" of previous agent

  2. Estimating divergently routed nonlinearly interfering channel powers using cross phase modulation.

    PubMed

    Chin, Hou-Man; Thakur, Manoj P; Thomsen, Benn C; Savory, Seb J

    2014-10-20

    The deployment of coherent transceivers in legacy networks requires significant investment in installation. We propose a method enabling autonomous (re-)configuration of an optical channel, which would be advantageous in legacy networks and necessary in proposed future networks utilizing a flexible frequency grid and software defined components such as reconfigurable optical add drop multiplexers (ROADM). We consider potential interfering optical channels propagating with the prospective channel along part of the fiber link which are dropped before arrival at the receiver. The method uses a commercially available line card transmitting a 40Gbit/s polarization multiplexed quadrature phase shift keying (PM-QPSK) probe channel to characterize an optical channel. The power of the nearest neighboring channels is then inferred by examining its bit error rate (BER) which is impacted by cross phase modulation (XPM) from the aggressor channels. In a 4 node network with 2 ROADMs using up to 6 aggressor OOK channels, we successfully deduce the neighboring channel power down to -2 dBm, and an extra improvement down to -3.5 dBm is gained, by measuring at an offset to the international telecommunication union (ITU) grid which also reveals inequality in neighbor channel powers.

  3. Pressure effects on stopping power of solids for channeled ions

    NASA Astrophysics Data System (ADS)

    Pathak, A. P.; Cruz, S. A.; Soullard, J.

    2005-01-01

    Pressure effects on the energy loss of swift channeled ions through silicon are considered. This is accomplished by estimating the changes in orbital charge densities and the corresponding mean ionization potentials, induced by increasing pressure. The bulk density for the compressed material is obtained from available experimental information on the corresponding equation of state for pressures up to 11.3 GPa, beyond which a structural phase transformation occurs. The high pressure is simulated by first caging the individual Si atom in a small spherical volume V and estimated as P=-partial derivative E/partial derivative V, where E is the total electronic energy for a particular confinement volume. The energy is selfconsistently calculated through a recently developed shell-wise version of the Thomas-Fermi-Dirac-Weizsacker density functional, which compares favorably with ab initio calculations on the basis of a cluster model where the Si atom is surrounded by neon (helium) atoms (in a molecular scheme). The resulting individual electronic shell charge densities are then averaged along planar channels to find the effective charge densities needed in the channeling energy loss calculations for channeled ions. The position dependence of the energy loss in the channels for the free and high-pressure case is calculated for 5 Me V protons and alpha particles along the (110) planar channels.

  4. A method for designing a variable-channel high-power cavity combiner

    NASA Astrophysics Data System (ADS)

    Liu, Yong-Tao; Huang, Gui-Rong; Shang, Lei; Lin, Hong-Xiang; Du, Bai-Ting

    2016-08-01

    Cavity combiners have been put forward for high power combining due to their advantages of larger combining ability, variable input channels and less power loss. For a high power cavity combiner, it is better to keep the power loss ratio in a reasonable range, because large power loss would lead to strict requirements on the cooling system. A combiner with variable input channels is convenient for outputting different power levels according to practical demands. In this paper, a method for designing a variable-channel high-power cavity combiner is proposed, based on the relation between input and output coupling coefficients obtained by analyzing the equivalent circuit of the cavity combiner. This method can put the designed cavity combiner in a matching state and keep its power loss rate in a reasonable range as the number of input channels changes. As an example, a cavity combiner with 500 MHz and variable input channels from 16 to 64 is designed, and the simulation results show that our proposed method is feasible. Supported by National Natural Science Foundation of China (11079034)

  5. Analysis of stationary power/amplitude distributions for multiple channels of sampled FBGs.

    PubMed

    Xing, Ya; Zou, Xihua; Pan, Wei; Yan, Lianshan; Luo, Bin; Shao, Liyang

    2015-08-10

    Stationary power/amplitude distributions for multiple channels of the sampled fiber Bragg grating (SFBG) along the grating length are analyzed. Unlike a uniform FBG, the SFBG has multiple channels in the reflection spectrum, not a single channel. Thus, the stationary power/amplitude distributions for these multiple channels are analyzed by using two different theoretical models. In the first model, the SFBG is regarded as a set of grating sections and non-grating sections, which are alternately stacked. A step-like distribution is obtained for the corresponding power/amplitude of each channel along the grating length. While, in the second model, the SFBG is decomposed into multiple uniform "ghost" gratings, and a continuous distribution is obtained for each ghost grating (i.e., each channel). After a comparison, the distributions obtained in the two models are identical, and the equivalence between the two models is demonstrated. In addition, the impacts of the duty cycle on the power/amplitude distributions of multiple channels of SFBG are presented. PMID:26368375

  6. Power losses in diffuse ultraviolet optical communications channels.

    PubMed

    Raptis, Nikos; Pikasis, Evangelos; Syvridis, Dimitris

    2016-09-15

    One of the most critical parameters in free-space optical communications systems operating in a non-line-of-sight regime are the optical losses. In this Letter, we numerically calculate these losses taking into account the scattering effects using the Monte Carlo simulation technique. The obtained results are compared with experimentally obtained data at 265 nm (solar-blind UV regime). A large set of measurements at distances up to 20 m, for different elevation angles of the transmitter (UV-LEDs) and receiver (photomultiplier tube) and for different atmospheric conditions has been taken for the characterization of the optical communications channel in terms of its loss properties. PMID:27628413

  7. Power losses in diffuse ultraviolet optical communications channels.

    PubMed

    Raptis, Nikos; Pikasis, Evangelos; Syvridis, Dimitris

    2016-09-15

    One of the most critical parameters in free-space optical communications systems operating in a non-line-of-sight regime are the optical losses. In this Letter, we numerically calculate these losses taking into account the scattering effects using the Monte Carlo simulation technique. The obtained results are compared with experimentally obtained data at 265 nm (solar-blind UV regime). A large set of measurements at distances up to 20 m, for different elevation angles of the transmitter (UV-LEDs) and receiver (photomultiplier tube) and for different atmospheric conditions has been taken for the characterization of the optical communications channel in terms of its loss properties.

  8. Temperature dependence of single-event burnout in n-channel power MOSFETs

    NASA Astrophysics Data System (ADS)

    Johnson, Gregory H.; Schrimpf, Ronald D.; Galloway, Kenneth F.; Koga, Rocky

    1992-12-01

    The temperature dependence of single-event burnout (SEB) in n-channel power MOSFETs is investigated experimentally and analytically. Experimental data are presented which indicate that the SEB susceptibility of the power MOSFET decreases with increasing temperature. A previously reported analytical model that describes the SEB mechanism is updated to include temperature variations. This model is shown to agree with the experimental trends.

  9. High-power AlGaAs channeled substrate planar diode lasers for spaceborne communications

    NASA Technical Reports Server (NTRS)

    Connolly, J. C.; Goldstein, B.; Pultz, G. N.; Slavin, S. E.; Carlin, D. B.; Ettenberg, M.

    1988-01-01

    A high power channeled substrate planar AlGaAs diode laser with an emission wavelength of 8600 to 8800 A was developed. The optoelectronic behavior (power current, single spatial and spectral behavior, far field characteristics, modulation, and astigmatism properties) and results of computer modeling studies on the performance of the laser are discussed. Lifetest data on these devices at high output power levels is also included. In addition, a new type of channeled substrate planar laser utilizing a Bragg grating to stabilize the longitudinal mode was demonstrated. The fabrication procedures and optoelectronic properties of this new diode laser are described.

  10. High-power 0.87-micron channel substrate planar lasers for spaceborne communications

    NASA Technical Reports Server (NTRS)

    Connolly, J. C.; Stewart, T. R.; Gilbert, D. B.; Slavin, S. E.; Carlin, D. B.

    1988-01-01

    High-power single-mode channeled-substrate planar AlGaAs diode lasers are being developed for reliable high-power operation for use as sources in spaceborne optical communication systems. The CSP laser structure has been optimized for operation at an emission wavelength of 870 nm. Such devices have exhibited output powers in excess of 80 mW CW at an operating temperature of 80 C.

  11. The effect of thermal pollution on benthic foraminiferal assemblages in the Mediterranean shoreface adjacent to Hadera power plant (Israel).

    PubMed

    Arieli, Ruthie Nina; Almogi-Labin, Ahuva; Abramovich, Sigal; Herut, Barak

    2011-05-01

    The thermal pollution patch of Hadera power plant was used as a natural laboratory to evaluate the potential long-term effects of rise in Eastern Mediterranean SST on living benthic foraminifera. Their sensitivity to environmental changes makes foraminifera ideal for this study. Ten monthly sampling campaigns were performed in four stations located along a temperature gradient up to 10 °C from the discharge site of heated seawater to a control station. The SST along this transect varied between 25/18 °C in winter and 36/31 °C in summer. A significant negative correlation was found between SST in all stations and benthic foraminiferal abundance, species richness and diversity. The total foraminiferal abundance and species richness was particularly low at the thermally polluted stations especially during summer when SST exceeded 30 °C, but also throughout the entire year. This indicates that thermal pollution has a detrimental effect on benthic foraminifera, irrelevant to the natural seasonal changes in SST.

  12. Do the coarsest bed fractions and stream power record contemporary trends in steep headwater channels?

    NASA Astrophysics Data System (ADS)

    Galia, Tomáš; Škarpich, Václav

    2016-11-01

    Three stream channels that were devoid of evidence of past debris flows and one headwater channel that contained debris flow deposits in the flysch western Carpathians, Czech Republic were selected to test relationships between in-channel processes, bed sediments, and unit stream power calculated for bankfull and Q20 flows. Contemporary depositional or erosional trends in the examined headwaters were linked with bed sediments that were represented by the coarsest cobble and boulder fraction with a mean calculated from the five largest particles. The downstream trends of the unit stream power were derived for a bankfull discharge and a well-documented 20-year flood event. In addition, the flow competences during the discharges were calculated using indirect bedload transport measurements. Downstream fining of the cobble and boulder fraction was observed in all of the studied headwaters, and unique downstream variations of the unit stream power were calculated for the longitudinal profiles. The single-thread streams that were devoid of evidence of debris flow events exhibited direct relations between the coarsest sediment size and the unit stream power, especially as calculated for the 20-year flood event and for erosional/depositional trends of the channel. The downstream coarsening of the bed material that was accompanied by an increase in the unit stream power was usually observed in the case of deeply incised (> 0.5 m above the assumed bankfull depth) channel reaches. The calculated competence of the 20-year flow was up to twofold higher than that required to entrain the largest bed particle diameters in those channel reaches, and even the bankfull flow was potentially capable of transporting the coarsest bed particles in certain of the reaches. On the other hand, some depositional channel reaches evidently led to the disconnectivity of transport of the coarsest bed material even in the case of the 20-year flood event. The longitudinal profile of the channel that

  13. Gelled propellant flow: Boundary layer theory for power-law fluids in a converging planar channel

    NASA Astrophysics Data System (ADS)

    Kraynik, Andrew M.; Geller, A. S.; Glick, J. H.

    1989-10-01

    A boundary layer theory for the flow of power-law fluids in a converging planar channel has been developed. This theory suggests a Reynolds number for such flows, and following numerical integration, a boundary layer thickness. This boundary layer thickness has been used in the generation of a finite element mesh for the finite element code FIDAP. FIDAP was then used to simulate the flow of power-law fluids through a converging channel. Comparison of the analytic and finite element results shows the two to be in very good agreement in regions where entrance and exit effects (not considered in the boundary layer theory) can be neglected.

  14. A low-power 32-channel digitally programmable neural recording integrated circuit.

    PubMed

    Wattanapanitch, W; Sarpeshkar, R

    2011-12-01

    We report the design of an ultra-low-power 32-channel neural-recording integrated circuit (chip) in a 0.18 μ m CMOS technology. The chip consists of eight neural recording modules where each module contains four neural amplifiers, an analog multiplexer, an A/D converter, and a serial programming interface. Each amplifier can be programmed to record either spikes or LFPs with a programmable gain from 49-66 dB. To minimize the total power consumption, an adaptive-biasing scheme is utilized to adjust each amplifier's input-referred noise to suit the background noise at the recording site. The amplifier's input-referred noise can be adjusted from 11.2 μVrms (total power of 5.4 μW) down to 5.4 μVrms (total power of 20 μW) in the spike-recording setting. The ADC in each recording module digitizes the a.c. signal input to each amplifier at 8-bit precision with a sampling rate of 31.25 kS/s per channel, with an average power consumption of 483 nW per channel, and, because of a.c. coupling, allows d.c. operation over a wide dynamic range. It achieves an ENOB of 7.65, resulting in a net efficiency of 77 fJ/State, making it one of the most energy-efficient designs for neural recording applications. The presented chip was successfully tested in an in vivo wireless recording experiment from a behaving primate with an average power dissipation per channel of 10.1 μ W. The neural amplifier and the ADC occupy areas of 0.03 mm(2) and 0.02 mm(2) respectively, making our design simultaneously area efficient and power efficient, thus enabling scaling to high channel-count systems.

  15. Temperature dependence of single-event burnout in n-channel power MOSFET's

    NASA Astrophysics Data System (ADS)

    Johnson, G. H.; Schrimpf, R. D.; Galloway, K. F.; Koga, R.

    1994-03-01

    The temperature dependence of single-event burnout (SEB) in n-channel power metal-oxide-semiconductor field effect transistors (MOSFET's) is investigated experimentally and analytically. Experimental data are presented which indicate that the SEB susceptibility of the power MOSFET decreases with increasing temperature. A previously reported analytical model that describes the SEB mechanism is updated to include temperature variations. This model is shown to agree with the experimental trends.

  16. Development of Pneumatic Channel Wing Powered-Lift Advanced Super-STOL Aircraft

    NASA Technical Reports Server (NTRS)

    Englar, Robert J.; Campbell, Bryan A.

    2002-01-01

    The powered-lift Channel Wing concept has been combined with pneumatic Circulation Control aerodynamic and propulsive technology to generate a Pneumatic Channel Wing configuration intended to have Super-STOL or VSTOL capability while eliminating many of the operational problem areas of the original Channel Wing vehicle. A preliminary design study of this pneumatic vehicle based on previous wind-tunnel and flight-test data for the two technologies integrated into a simple Pneumatic Channel Wing (PCW) configuration showed very strong Super-STOL potential. Wind-tunnel development and evaluations of a PCW powered model conducted at Georgia Tech Research Institute (GTRI) have shown substantial lift capabilities for the blown configuration (C(sub L) values of 8.5 to 9.0). Variation in blowing of the channel was shown to be more efficient than variation in propeller thrust. Also revealed was the ability to operate unstalled at very high angles of attack of 40 deg-45 deg, or to achieve very high lift at much lower angle of attack to increase visibility and controllability. In order to provide greater flexibility in Super-STOL takeoffs and landings, the blown model also displayed the ability to interchange thrust and drag by varying blowing without any moving parts. This paper presents these experimental results, discusses variations in the configuration geometry under development, and extends this integrated technology to advanced design studies of PCW-type vehicles.

  17. Ultra-compact 1 × 8 Channel terahertz Wave Power Splitter

    NASA Astrophysics Data System (ADS)

    Hu, Jian-Rong; Li, Jiu-Sheng

    2016-08-01

    Relying on 1 × 2 photonic crystal waveguide and photonic crystal resonator, a compact eight-channel terahertz wave power splitter is proposed. The mechanism of such a device is further theoretically analyzed and numerically investigated with the aid of the plane wave expansion method and the finite-difference time-domain method. With an appropriate design, the proposed power splitter can split the input terahertz wave energy equally into eight output ports at the frequency of 0.667 THz. Furthermore, the total size of the present device is of 4.33 mm × 3.74 mm. Due to its small size, the multi-channel terahertz wave power splitter has practical applications in the terahertz wave integrated circuit fields.

  18. Design and realization of the low voltage power line carrier channel simulation platform

    NASA Astrophysics Data System (ADS)

    Zhang, Xuhui; Zhang, Liyong; Zou, Bing; Zhang, Xuhai

    2006-11-01

    Proposed a visualized modeling and simulating scheme on the basis of object-oriented software for the power line communication channels. Combined with the research on the theories about transmitting lines, applies a equivalent concentrated parameter model to replace the traditional distributed parameter model of the transmitting lines, and studied the realizing process of the simulation. Constructed the network topology model database, noise model database, typical load model database aiming at the low-voltage power line features. And developed a visual, easy-to-operate power line communication simulation platform under Windows operation system.

  19. Power Scaling of Uplink Massive MIMO Systems With Arbitrary-Rank Channel Means

    NASA Astrophysics Data System (ADS)

    Zhang, Qi; Jin, Shi; Wong, Kai-Kit; Zhu, Hongbo; Matthaiou, Michail

    2014-10-01

    This paper investigates the uplink achievable rates of massive multiple-input multiple-output (MIMO) antenna systems in Ricean fading channels, using maximal-ratio combining (MRC) and zero-forcing (ZF) receivers, assuming perfect and imperfect channel state information (CSI). In contrast to previous relevant works, the fast fading MIMO channel matrix is assumed to have an arbitrary-rank deterministic component as well as a Rayleigh-distributed random component. We derive tractable expressions for the achievable uplink rate in the large-antenna limit, along with approximating results that hold for any finite number of antennas. Based on these analytical results, we obtain the scaling law that the users' transmit power should satisfy, while maintaining a desirable quality of service. In particular, it is found that regardless of the Ricean $K$-factor, in the case of perfect CSI, the approximations converge to the same constant value as the exact results, as the number of base station antennas, $M$, grows large, while the transmit power of each user can be scaled down proportionally to $1/M$. If CSI is estimated with uncertainty, the same result holds true but only when the Ricean $K$-factor is non-zero. Otherwise, if the channel experiences Rayleigh fading, we can only cut the transmit power of each user proportionally to $1/\\sqrt M$. In addition, we show that with an increasing Ricean $K$-factor, the uplink rates will converge to fixed values for both MRC and ZF receivers.

  20. Zinc oxide integrated area efficient high output low power wavy channel thin film transistor

    SciTech Connect

    Hanna, A. N.; Ghoneim, M. T.; Bahabry, R. R.; Hussain, A. M.; Hussain, M. M.

    2013-11-25

    We report an atomic layer deposition based zinc oxide channel material integrated thin film transistor using wavy channel architecture allowing expansion of the transistor width in the vertical direction using the fin type features. The experimental devices show area efficiency, higher normalized output current, and relatively lower power consumption compared to the planar architecture. This performance gain is attributed to the increased device width and an enhanced applied electric field due to the architecture when compared to a back gated planar device with the same process conditions.

  1. Channel

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03693 Channel

    This channel is located south of Iani Chaos.

    Image information: VIS instrument. Latitude -10.9N, Longitude 345.5E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  2. Wirelessly powered micro-tracer enabled by miniaturized antenna and microfluidic channel

    NASA Astrophysics Data System (ADS)

    Duan, G.; Zhao, X.; Seren, H. R.; Chen, C.; Zhang, X.

    2015-12-01

    A miniaturized antenna, 380μm by 380μm in size, was fabricated and integrated with a commercialized passive RFID chip to form a micro-tracer, whose size was 2mm by 1mm in total. The micro-tracer was wirelessly powered and interrogated by a single layer spiral reader antenna through near field coupling. To maximize the working distance, the resonant frequency of micro-tracer and reader antenna were matched at 840MHz. Due to the ultra small size of the tracer antenna, power transfer efficiency decreased dramatically as the distance between tracer antenna and reader antenna increased, thus the working distance of the microtracer was limited within 1mm. To achieve massive operation of the micro-tracer, a microfluidic platform was fabricated with in channel focusing and separation. Acrylic sheets were laser cut to define the channel and cover structure, then bonded together layer by layer with a glass substrate, on which reader antenna was integrated. Pump oil was used as the fluidic media carrying the micro-tracer flowing inside the microfluidic channel. The wireless power transfer and real-time communication was demonstrated with the micro-tracer flowing above the reader antenna, as the ID of the micro-tracer was retrieved and displayed on a computer screen.

  3. Geomorphic effects, flood power, and channel competence of a catastrophic flood in confined and unconfined reaches of the upper Lockyer valley, southeast Queensland, Australia

    NASA Astrophysics Data System (ADS)

    Thompson, Chris; Croke, Jacky

    2013-09-01

    Flooding is a persistent natural hazard, and even modest changes in future climate are believed to lead to large increases in flood magnitude. Previous studies of extreme floods have reported a range of geomorphic responses from negligible change to catastrophic channel change. This paper provides an assessment of the geomorphic effects of a rare, high magnitude event that occurred in the Lockyer valley, southeast Queensland in January 2011. The average return interval of the resulting flood was ~ 2000 years in the upper catchment and decreased to ~ 30 years downstream. A multitemporal LiDAR-derived DEM of Difference (DoD) is used to quantify morphological change in two study reaches with contrasting valley settings (confined and unconfined). Differences in geomorphic response between reaches are examined in the context of changes in flood power, channel competence and degree of valley confinement using a combination of one-dimensional (1-D) and two-dimensional (2-D) hydraulic modelling. Flood power peaked at 9800 W m- 2 along the confined reach and was 2-3 times lower along the unconfined reach. Results from the DoD confirm that the confined reach was net erosional, exporting ~ 287,000 m3 of sediment whilst the unconfined reach was net depositional gaining ~ 209,000 m3 of sediment, 70% of the amount exported from the upstream, confined reach. The major sources of eroded sediment in the confined reach were within channel benches and macrochannel banks resulting in a significant increase of channel width. In the unconfined reach, the benches and floodplains were the major loci for deposition, whilst the inner channel exhibited minor width increases. The presence of high stream power values, and resultant high erosion rates, within the confined reach is a function of the higher energy gradient of the steeper channel that is associated with knickpoint development. Dramatic differences in geomorphic responses were observed between the two adjacent reaches of

  4. Open channel current noise analysis of S6 peptides from KvAP channel on bilayer lipid membrane shows bimodal power law scaling

    NASA Astrophysics Data System (ADS)

    Shrivastava, Rajan; Malik, Chetan; Ghosh, Subhendu

    2016-06-01

    Open channel current noise in synthetic peptide S6 of KvAP channel was investigated in a voltage clamp experiment on bilayer lipid membrane (BLM). It was observed that the power spectral density (PSD) of the component frequencies follows power law with different slopes in different frequency ranges. In order to know the origin of the slopes PSD analysis was done with signal filtering. It was found that the first slope in the noise profile follows 1 / f pattern which exists at lower frequencies and has high amplitude current noise, while the second slope corresponds to 1 /f 2 - 3 pattern which exists at higher frequencies with low amplitude current noise. In addition, white noise was observed at very large frequencies. It was concluded that the plausible reason for the multiple power-law scaling is the existence of different modes of non-equilibrium ion transport through the S6 channel.

  5. On-line calibration of process instrumentation channels in nuclear power plants

    SciTech Connect

    Hashemian, H.M.; Farmer, J.P.

    1995-04-01

    An on-line instrumentation monitoring system was developed and validated for use in nuclear power plants. This system continuously monitors the calibration status of instrument channels and determines whether or not they require manual calibrations. This is accomplished by comparing the output of each instrument channel to an estimate of the process it is monitoring. If the deviation of the instrument channel from the process estimate is greater than an allowable limit, then the instrument is said to be {open_quotes}out of calibration{close_quotes} and manual adjustments are made to correct the calibration. The success of the on-line monitoring system depends on the accuracy of the process estimation. The system described in this paper incorporates both simple intercomparison techniques as well as analytical approaches in the form of data-driven empirical modeling to estimate the process. On-line testing of the calibration of process instrumentation channels will reduce the number of manual calibrations currently performed, thereby reducing both costs to utilities and radiation exposure to plant personnel.

  6. PEALL4: a 4-channel, 12-bit, 40-MSPS, Power Efficient and Low Latency SAR ADC

    NASA Astrophysics Data System (ADS)

    Rarbi, F.; Dzahini, D.; Gallin-Martel, L.; Bouvier, J.; Zeloufi, M.; Trocme, B.; Gabaldon Ruiz, C.

    2015-01-01

    The PEALL4 chip is a Power Efficient And Low Latency 4-channels, 12-bit and 40-MSPS successive approximation register (SAR) ADC. It was designed featuring a very short latency time in the context of ATLAS Liquid Argon Calorimeter phase I upgrade. Moreover this design could be a good option for ATLAS phase II and other High Energy Physics (HEP) projects. The full functionality of the converter is achieved by an embedded high-speed clock frequency conversion generated by the ADC itself. The design and testing results of the PEALL4 chip implemented in a commercial 130nm CMOS process are presented. The size of this 4-channel ADC with embedded voltage references and sLVS output serializer is 2.8x3.4 mm2. The chip presents a short latency time less than 25 ns defined from the very beginning of the sampling to the last conversion bit made available. A total power consumption below 27mW per channel is measured including the reference buffer and the sLVS serializer.

  7. Simulating single-event burnout of n-channel power MOSFET's

    SciTech Connect

    Johnson, G.H.; Hohl, J.H.; Schrimpf, R.D.; Galloway, K.F. )

    1993-05-01

    Heavy ions are ubiquitous in a space environment. Single-event burnout of power MOSFET's is a sudden catastrophic failure mechanism that is initiated by the passage of a heavy ion through the device structure. The passage of the heavy ion generates a current filament that locally turns on a parasitic n-p-n transistor inherent to the power MOSFET. Subsequent high currents and high voltage in the device induce second breakdown of the parasitic bipolar transistor and hence meltdown of the device. This paper presents a model that can be used for simulating the burnout mechanism in order to gain insight into the significant device parameters that most influence the single-event burnout susceptibility of n-channel power MOSFET's.

  8. 47 CFR 74.710 - Digital low power TV and TV translator station protection.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... site within the protected contour of a co-channel or adjacent channel digital low power TV or TV... translator or TV booster station at the protected contour of a co-channel digital TV or TV translator station... the low power TV, TV translator or TV booster station at the protected contour of a digital low...

  9. 47 CFR 74.710 - Digital low power TV and TV translator station protection.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... site within the protected contour of a co-channel or adjacent channel digital low power TV or TV... translator or TV booster station at the protected contour of a co-channel digital TV or TV translator station... the low power TV, TV translator or TV booster station at the protected contour of a digital low...

  10. Design and analysis of large-core multitrench channel waveguide for high-power applications.

    PubMed

    Saini, Than Singh; Kumar, Ajeet; Sinha, Ravindra Kumar

    2015-07-01

    We present a multitrench leaky channel waveguide design that supports effective single-mode operation even with large-core size. The proposed waveguide structure has a uniform rectangular core and a geometrically shaped trench-assisted cladding in such a way that all the confined modes become leaky. The effective single-mode operation is achieved by choosing the appropriate geometrical parameters that introduce very large leakage losses for higher-order modes with very low leakage losses for fundamental mode. A power law profile for cladding geometry is considered to explore the effect of trenches on the effective single-mode operation. The finite element method is used to calculate the leakage losses of the modes. Our numerical results show that the waveguide ensures extended single-mode operation in the wavelength range of 1.25-2.0 μm with the rectangular core area as large as 100  μm2. Such a large-core-area waveguide structure efficiently suppresses unwanted nonlinear optical effects. A proposed channel waveguide structure with a large core size is suitable for high-power delivery devices such as high-power waveguide lasers and amplifiers.

  11. Constraining minimum-norm inverse by phase synchronization and signal power of the scalp EEG channels.

    PubMed

    Majumdar, Kaushik

    2009-04-01

    In this paper, the goal is to further improve the output of the scalp EEG source localization by the Euclidean minimum-norm (MN) inverse during single trials. Trials have been selected based on signal power at specific time intervals in specific locations. Then the source localization has been performed by MN. It has been observed that close to a dominant cortical source of EEG, as determined by the MN, both pairwise phase synchronization of a channel with its nearest neighbors and the cumulative signal power of the channels within that neighborhood become high (normalized values remain above certain thresholds). This has also been verified through simulations on the subject's real head model. The conclusion of our study is that only those sources are to be chosen for which MN inverse, and signal power and phase synchronization profile converge. A novel fast Fourier transform (FFT) based phase synchronization measuring algorithm between a pair of signals has been developed whose time complexity is no more than that of the FFT.

  12. Flow of power-law fluids in self-affine fracture channels.

    PubMed

    Yan, Yiguang; Koplik, Joel

    2008-03-01

    The two-dimensional pressure driven flow of non-Newtonian power-law fluids in self-affine fracture channels at finite Reynolds number is calculated. The channels have constant mean aperture and two values zeta=0.5 and 0.8 of the Hurst exponent are considered. The calculation is based on the lattice-Boltzmann method, using a different technique to obtain a power-law variation in viscosity, and the behavior of shear-thinning, Newtonian, and shear-thickening liquids is compared. Local aspects of the flow fields, such as maximum velocity and pressure fluctuations, are studied, and the non-Newtonian fluids are compared to the (previously studied) Newtonian case. We find a scaling relation between permeability and mean aperture in the low Reynolds number regime, generalizing an earlier result for Newtonian fluids. As the Reynolds number increases, we observe the same sequence of transitions to nonlinearity found in intergranular porous media. Furthermore, the permeability results may be collapsed into a master curve of friction factor vs Reynolds number, using a scaling similar to that employed for power-law fluids in porous media.

  13. High-power waveguide CO2 laser for formation of deep channels in biological tissue

    NASA Astrophysics Data System (ADS)

    Vasiltsov, Victor V.; Golubev, Vladimir S.; Dubrov, V. D.; Egorov, E. N.; Panchenko, Vladislav Y.; Zabelin, Alexandre M.; Zelenov, Evgenii V.; Kubyshkin, Alexander P.; Roshin, A. P.; Ulyanov, Valerii A.

    1998-06-01

    The paper presents the description of a high-power waveguide single-mode CO2 laser generating 800 W average beam power and up to 1 kW peak power at pulse duration from 2 to 100 ms. The diffusion-cooled active medium is excited by a capacitive AC discharge of sound frequency. The advantages of the laser are: high (>10%) technical efficiency, upgraded stability of beam parameters at the cost of the use of waveguide generation mode, extremely low (<1 nl/h) consumption of lasing mixture and possibility of operation in quasi-sealed-off regime; design simplicity, compactness and low cost. As an example of application of various capabilities of these lasers, a description of the developed medical system `Genom-4' used in the transmyocardial revascularization (TMR) procedure is presented. The system is equipped with devices which are necessary both to conducting biophysical experiments and to performing operations under clinical conditions; among them are computer control system, cardiograph for synchronization of laser pulse with ECG of the heart under operation, remote articulated mirror manipulator with optical hand-piece for performing operations. The results of biophysical experiments on drilling channels in organic materials and biological tissues in vitro, as well as the results of operations on patients, are presented. Verification of a possible negative influence of shock waves, which can be generated in biotissues during the TMR procedure, has been studied. It has been shown that the pressure excess due to laser action is lower than one bar. Thus, no destruction of biotissues surrounding the channel should be caused. The autodyne Doppler spectroscopy diagnostics of specifying the moment of keyhole punching in myocardium has been discussed. Other possible applications of the system for drilling deep channels in liver, lungs, etc. are mentioned.

  14. Implementation of a galvanically isolated low-noise power supply board for multi-channel headstage preamplifiers.

    PubMed

    Tóth, Attila; Máthé, Kálmán; Petykó, Zoltán; Szabó, Imre; Czurkó, András

    2008-06-15

    Custom made multi-channel headstage preamplifiers are traditionally powered by battery. By the use of an isolated unregulated DC/DC converter integrated circuit (DCP010512B from Texas Instruments Inc., TX, USA), here we describe the implementation of a galvanically isolated low-noise power supply board for multi-channel headstage preamplifiers. The implemented galvanically isolated power supply board provides the same quality noise free recording as the battery power supply. The non-isolated part of the power supply board is powered by standard 230 V AC/6 V DC wall mount adapter or USB cable. The described galvanically isolated power supply board can replace the batteries in preamplifier power supplies without any deterioration of the quality of recordings.

  15. Implementation of a galvanically isolated low-noise power supply board for multi-channel headstage preamplifiers.

    PubMed

    Tóth, Attila; Máthé, Kálmán; Petykó, Zoltán; Szabó, Imre; Czurkó, András

    2008-06-15

    Custom made multi-channel headstage preamplifiers are traditionally powered by battery. By the use of an isolated unregulated DC/DC converter integrated circuit (DCP010512B from Texas Instruments Inc., TX, USA), here we describe the implementation of a galvanically isolated low-noise power supply board for multi-channel headstage preamplifiers. The implemented galvanically isolated power supply board provides the same quality noise free recording as the battery power supply. The non-isolated part of the power supply board is powered by standard 230 V AC/6 V DC wall mount adapter or USB cable. The described galvanically isolated power supply board can replace the batteries in preamplifier power supplies without any deterioration of the quality of recordings. PMID:18372046

  16. Adjacent segment disease.

    PubMed

    Virk, Sohrab S; Niedermeier, Steven; Yu, Elizabeth; Khan, Safdar N

    2014-08-01

    EDUCATIONAL OBJECTIVES As a result of reading this article, physicians should be able to: 1. Understand the forces that predispose adjacent cervical segments to degeneration. 2. Understand the challenges of radiographic evaluation in the diagnosis of cervical and lumbar adjacent segment disease. 3. Describe the changes in biomechanical forces applied to adjacent segments of lumbar vertebrae with fusion. 4. Know the risk factors for adjacent segment disease in spinal fusion. Adjacent segment disease (ASD) is a broad term encompassing many complications of spinal fusion, including listhesis, instability, herniated nucleus pulposus, stenosis, hypertrophic facet arthritis, scoliosis, and vertebral compression fracture. The area of the cervical spine where most fusions occur (C3-C7) is adjacent to a highly mobile upper cervical region, and this contributes to the biomechanical stress put on the adjacent cervical segments postfusion. Studies have shown that after fusion surgery, there is increased load on adjacent segments. Definitive treatment of ASD is a topic of continuing research, but in general, treatment choices are dictated by patient age and degree of debilitation. Investigators have also studied the risk factors associated with spinal fusion that may predispose certain patients to ASD postfusion, and these data are invaluable for properly counseling patients considering spinal fusion surgery. Biomechanical studies have confirmed the added stress on adjacent segments in the cervical and lumbar spine. The diagnosis of cervical ASD is complicated given the imprecise correlation of radiographic and clinical findings. Although radiological and clinical diagnoses do not always correlate, radiographs and clinical examination dictate how a patient with prolonged pain is treated. Options for both cervical and lumbar spine ASD include fusion and/or decompression. Current studies are encouraging regarding the adoption of arthroplasty in spinal surgery, but more long

  17. JPL 2-to-the-20th-power channel 300 MHz bandwidth digital spectrum analyzer

    NASA Technical Reports Server (NTRS)

    Morris, G. A., Jr.; Wilck, H. C.

    1978-01-01

    A million (two to the 20th power) channel, 300 MHz bandwidth, digital spectrum analyzer was considered. The design, fabrication, and maintenance philosophy of the modular, pipelined, fast fourier transform (FFT) hardware are described. The spectrum analyzer will be used to examine the region from 1.4 GHz to 26 GHz for radio frequency interference which may be harmful to present and future tracking missions of the Deep Space Network. The design has application to the search for extraterrestrial intelligence signals and radio science phenomena.

  18. AlGaN Channel Transistors for Power Management and Distribution

    NASA Technical Reports Server (NTRS)

    VanHove, James M.

    1996-01-01

    Contained within is the Final report of a Phase 1 SBIR program to develop AlGaN channel junction field effect transistors (JFET). The report summarizes our work to design, deposit, and fabricate JFETS using molecular beam epitaxy growth AlGaN. Nitride growth is described using a RF atomic nitrogen plasma source. Processing steps needed to fabricate the device such as ohmic source-drain contacts, reactive ion etching, gate formation, and air bride fabrication are documented. SEM photographs of fabricated power FETS are shown. Recommendations are made to continue the effort in a Phase 2 Program.

  19. Highly reliable high-power superluminescent diodes with three single-mode active channels

    NASA Astrophysics Data System (ADS)

    Andreeva, E. V.; Il'chenko, S. N.; Kurnyavko, Yu V.; Luk'yanov, V. N.; Shidlovskii, V. R.; Yakubovich, S. D.

    2016-07-01

    We report superluminescent diodes (SLDs) with three ridged active channels, each having a width of 3.5 μm, based on one 'bulk' and two quantum-well heterostructures. At a cw output power greater than 100 mW, the emission spectra of these SLDs possess a quasi-Gaussian shape with centre wavelengths near 840, 860 and 1060 nm and widths about 15, 25 and 40 nm, respectively. In the above operating conditions, the median service life of the SLDs amounted to approximately 50000, 25000 and more than 60000 h, respectively.

  20. High-power, kilojoule class laser channeling in millimeter scale underdense plasma

    NASA Astrophysics Data System (ADS)

    Willingale, Louise

    2010-11-01

    The interaction of high-energy, relativistic laser pulses with underdense plasma is of fundamental interest relevant to laser propagation phenomena, particle acceleration, x-ray generation and blast wave studies. In particular, the hole-boring fast-ignition scheme for inertial confinement fusion requires an ignition pulse to channel through millimeter scale underdense plasma to reach the dense fuel core. Experiments were performed using the OMEGA EP facility 9 ps short-pulse laser, with pulse energy 750 ; J (corresponding to 90 TW power and focused peak intensity of 5 x10^19 ; Wcm-2) to investigate the interaction with a millimeter-scale, low-density plasma plume, generated by a long-pulse interaction with CH target. The second short-pulse beam generates a proton probe beam from a thin-foil target, which gives high-quality images of the electromagnetic fields generated in the interactions. The evolution and early time expansion of the channel is measured on a single shot using this method. At later times, the channel has evolved to show a strong instability. Plasmas up to near-critical density were also investigated by using low-density foam targets. Large-scale 2D particle-in-cell simulations using the OSIRIS code are performed to model the interactions and investigate the observed physical phenomenon. In collaboration with P. M. Nilson, A. G. R. Thomas, J. Cobble, R. S. Craxton, K. Flippo, A. Maksimchuk, W. Nazarov, P.A. Norreys, T. C. Sangster, R. H. H. Scott, C. Stoeckl, C. Zulick, and K. Krushelnick.

  1. 52. EASTSIDE PLANT: GENERAL VIEW OF GOVERNOR ADJACENT TO GENERATOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    52. EASTSIDE PLANT: GENERAL VIEW OF GOVERNOR ADJACENT TO GENERATOR - American Falls Water, Power & Light Company, Island Power Plant, Snake River, below American Falls Dam, American Falls, Power County, ID

  2. Peristaltic Creeping Flow of Power Law Physiological Fluids through a Nonuniform Channel with Slip Effect

    PubMed Central

    Chaube, M. K.; Tripathi, D.; Bég, O. Anwar; Sharma, Shashi; Pandey, V. S.

    2015-01-01

    A mathematical study on creeping flow of non-Newtonian fluids (power law model) through a nonuniform peristaltic channel, in which amplitude is varying across axial displacement, is presented, with slip effects included. The governing equations are simplified by employing the long wavelength and low Reynolds number approximations. The expressions for axial velocity, stream function, pressure gradient, and pressure difference are obtained. Computational and numerical results for velocity profile, pressure gradient, and trapping under the effects of slip parameter, fluid behavior index, angle between the walls, and wave number are discussed with the help of Mathematica graphs. The present model is applicable to study the behavior of intestinal flow (chyme movement from small intestine to large intestine). It is also relevant to simulations of biomimetic pumps conveying hazardous materials, polymers, and so forth. PMID:27057132

  3. Effect of the variable cross-section channel on performance of a cusped field thruster at low power

    NASA Astrophysics Data System (ADS)

    Liu, Hui; Chen, Pengbo; Mao, Wei; Yu, Daren; Wang, Chunsheng

    2015-09-01

    The cusped field thruster has drawn much attention from many institutions due to its wide thrust range, high impulse, and long lifetime. However, lots of experimental results reveal that the cusped field thruster at low power has a poor performance. A cusped field thruster with a variable cross-section channel by putting a ceramic spacer in the channel is introduced in this paper, aimed at improving the thruster performance at low power. The DSMC results validate that the upstream atom density can be increased by a spacer, especially near the wall. Based on simulated results, spacers are put into different positions of the channel. The experimental results show that a suitable spacer can enhance thruster performance at low power, which can be confirmed by the results that the anode efficiency can achieve 40% at 400 V anode voltage and 20 sccm gas flow rate by contrast to 35% without a spacer under the same condition.

  4. A computational analysis of natural convection in a vertical channel with a modified power law non-Newtonian fluid

    SciTech Connect

    Lee, S.R.; Irvine, T.F. Jr.; Greene, G.A.

    1998-04-01

    An implicit finite difference method was applied to analyze laminar natural convection in a vertical channel with a modified power law fluid. This fluid model was chosen because it describes the viscous properties of a pseudoplastic fluid over the entire shear rate range likely to be found in natural convection flows since it covers the shear rate range from Newtonian through transition to simple power law behavior. In addition, a dimensionless similarity parameter is identified which specifies in which of the three regions a particular system is operating. The results for the average channel velocity and average Nusselt number in the asymptotic Newtonian and power law regions are compared with numerical data in the literature. Also, graphical results are presented for the velocity and temperature fields and entrance lengths. The results of average channel velocity and Nusselt number are given in the three regions including developing and fully developed flows. As an example, a pseudoplastic fluid (carboxymethyl cellulose) was chosen to compare the different results of average channel velocity and Nusselt number between a modified power law fluid and the conventional power law model. The results show, depending upon the operating conditions, that if the correct model is not used, gross errors can result.

  5. Scaling of the power exhaust channel in Alcator C-Moda)

    NASA Astrophysics Data System (ADS)

    LaBombard, B.; Terry, J. L.; Hughes, J. W.; Brunner, D.; Payne, J.; Reinke, M. L.; Cziegler, I.; Granetz, R.; Greenwald, M.; Hutchinson, I. H.; Irby, J.; Lin, Y.; Lipschultz, B.; Ma, Y.; Marmar, E. S.; Rowan, W. L.; Tsujii, N.; Wallace, G.; Whyte, D. G.; Wolfe, S.; Wukitch, S.; Wurden, G.; Team, Alcator C-Mod

    2011-05-01

    Parametric dependences of the heat flux footprint on the outer divertor target plate are explored in EDA H-mode and ohmic L-mode plasmas over a wide range of parameters with attached plasma conditions. Heat flux profile shapes are found to be independent of toroidal field strength, independent of power flow along magnetic field lines and insensitive to x-point topology (single-null versus double-null). The magnitudes and widths closely follow that of the "upstream" pressure profile, which are correlated to plasma thermal energy content and plasma current. Heat flux decay lengths near the strike-point in H- and L-mode plasmas scale approximately with the inverse of plasma current, with a diminished dependence at high collisionality in L-mode. Consistent with previous studies, pressure gradients in the boundary scale with plasma current squared, holding the magnetohydrodynamic ballooning parameter approximately invariant at fixed collisionality—strong evidence that critical-gradient transport physics plays a key role in setting the power exhaust channel.

  6. Design and analysis of trench-assisted leaky channel waveguide for high power applications

    NASA Astrophysics Data System (ADS)

    Pandey, Himanshu; Saini, Than Singh; Kumar, Ajeet

    2016-05-01

    We purpose a leaky channel waveguide design that supports a single guided mode. The waveguide works on the principle of higher-order mode discrimination. The cladding of waveguide is formed by alternate low and high index regions, which helps to leak out of higher-order modes while retaining the fundamental mode over the entire length of the waveguide. The Structure is analysed by the finite element method 'Comsol Multiphysics' and the leakage losses of the modes along with effective mode area have been calculated. We show that a waveguide formed in silica with core width 6 µm can be designed to exhibit single mode operation at 1550 nm wavelength. The Fundamental loss E11 = 0.076 dB/mm and the higher order loss E21 = 11.4 dB/mm with the rectangular core area as large as 50 µm2. Such large-core-area waveguide structure efficiently suppresses unwanted non-linear optical effects and is suitable for high power devices such as high power Waveguide Laser and Amplifier.

  7. Low complexity interference alignment algorithms for desired signal power maximization problem of MIMO channels

    NASA Astrophysics Data System (ADS)

    Sun, Cong; Yang, Yunchuan; Yuan, Yaxiang

    2012-12-01

    In this article, we investigate the interference alignment (IA) solution for a K-user MIMO interference channel. Proper users' precoders and decoders are designed through a desired signal power maximization model with IA conditions as constraints, which forms a complex matrix optimization problem. We propose two low complexity algorithms, both of which apply the Courant penalty function technique to combine the leakage interference and the desired signal power together as the new objective function. The first proposed algorithm is the modified alternating minimization algorithm (MAMA), where each subproblem has closed-form solution with an eigenvalue decomposition. To further reduce algorithm complexity, we propose a hybrid algorithm which consists of two parts. As the first part, the algorithm iterates with Householder transformation to preserve the orthogonality of precoders and decoders. In each iteration, the matrix optimization problem is considered in a sequence of 2D subspaces, which leads to one dimensional optimization subproblems. From any initial point, this algorithm obtains precoders and decoders with low leakage interference in short time. In the second part, to exploit the advantage of MAMA, it continues to iterate to perfectly align the interference from the output point of the first part. Analysis shows that in one iteration generally both proposed two algorithms have lower computational complexity than the existed maximum signal power (MSP) algorithm, and the hybrid algorithm enjoys lower complexity than MAMA. Simulations reveal that both proposed algorithms achieve similar performances as the MSP algorithm with less executing time, and show better performances than the existed alternating minimization algorithm in terms of sum rate. Besides, from the view of convergence rate, simulation results show that the MAMA enjoys fastest speed with respect to a certain sum rate value, while hybrid algorithm converges fastest to eliminate interference.

  8. Development of Relations of Stream Stage to Channel Geometry and Discharge for Stream Segments Simulated with Hydrologic Simulation Program-Fortran (HSPF), Chesapeake Bay Watershed and Adjacent Parts of Virginia, Maryland, and Delaware

    USGS Publications Warehouse

    Moyer, Douglas; Bennett, Mark

    2007-01-01

    The U.S. Geological Survey (USGS), U.S. Environmental Protection Agency (USEPA), Chesapeake Bay Program (CBP), Interstate Commission for the Potomac River Basin (ICPRB), Maryland Department of the Environment (MDE), Virginia Department of Conservation and Recreation (VADCR), and University of Maryland (UMD) are collaborating to improve the resolution of the Chesapeake Bay Regional Watershed Model (CBRWM). This watershed model uses the Hydrologic Simulation Program-Fortran (HSPF) to simulate the fate and transport of nutrients and sediment throughout the Chesapeake Bay watershed and extended areas of Virginia, Maryland, and Delaware. Information from the CBRWM is used by the CBP and other watershed managers to assess the effectiveness of water-quality improvement efforts as well as guide future management activities. A critical step in the improvement of the CBRWM framework was the development of an HSPF function table (FTABLE) for each represented stream channel. The FTABLE is used to relate stage (water depth) in a particular stream channel to associated channel surface area, channel volume, and discharge (streamflow). The primary tool used to generate an FTABLE for each stream channel is the XSECT program, a computer program that requires nine input variables used to represent channel morphology. These input variables are reach length, upstream and downstream elevation, channel bottom width, channel bankfull width, channel bankfull stage, slope of the floodplain, and Manning's roughness coefficient for the channel and floodplain. For the purpose of this study, the nine input variables were grouped into three categories: channel geometry, Manning's roughness coefficient, and channel and floodplain slope. Values of channel geometry for every stream segment represented in CBRWM were obtained by first developing regional regression models that relate basin drainage area to observed values of bankfull width, bankfull depth, and bottom width at each of the 290 USGS

  9. Multi-channel programmable power supply with temperature compensation for silicon sensors

    NASA Astrophysics Data System (ADS)

    Shukla, R. A.; Achanta, V. G.; Dugad, S. R.; Freeman, J.; Garde, C. S.; Gupta, S. K.; Khandekar, P. D.; Kurup, A. M.; Lokhandwala, S. S.; Los, S.; Prabhu, S. S.; Rakshe, P. S.

    2016-01-01

    Silicon Photo-Multipliers (SiPMs) are increasingly becoming popular for discrete photon counting applications due to the wealth of advantages they offer over conventional photo-detectors such as photo-multiplier tubes and hybrid photo-diodes. SiPMs are used in variety of applications ranging from high energy physics and nuclear physics experiments to medical diagnostics. The gain of a SiPM is directly proportional to the difference between applied and breakdown voltage of the device. However, the breakdown voltage depends critically on the ambient temperature and has a large temperature co-efficient in the range of 40-60 mV/°C resulting in a typical gain variation of 3%-5%/°C [Dinu et al., in IEEE Nuclear Science Symposium, Medical Imaging Conference and 17th Room Temperature Semiconductor Detector Workshop (IEEE, 2010), p. 215]. We plan to use the SiPM as a replacement for PMT in the cosmic ray experiment (GRAPES-3) at Ooty [Gupta et al., Nucl. Instrum. Methods Phys. Res., Sect. A 540, 311 (2005)]. There the SiPMs will be operated in an outdoor environment subjected to temperature variation of about 15 °C over a day. A gain variation of more than 50% was observed for such large variations in the temperature. To stabilize the gain of the SiPM under such operating conditions, a low-cost, multi-channel programmable power supply (0-90 V) was designed that simultaneously provides the bias voltage to 16 SiPMs. The programmable power supply (PPS) was designed to automatically adjust the operating voltage for each channel with a built-in closed loop temperature feedback mechanism. The PPS provides bias voltage with a precision of 6 mV and measures the load current with a precision of 1 nA. Using this PPS, a gain stability of 0.5% for SiPM (Hamamatsu, S10931-050P) has been demonstrated over a wide temperature range of 15 °C. The design methodology of the PPS system, its validation, and the results of the tests carried out on the SiPM is presented in this article. The

  10. Multi-channel programmable power supply with temperature compensation for silicon sensors.

    PubMed

    Shukla, R A; Achanta, V G; Dugad, S R; Freeman, J; Garde, C S; Gupta, S K; Khandekar, P D; Kurup, A M; Lokhandwala, S S; Los, S; Prabhu, S S; Rakshe, P S

    2016-01-01

    Silicon Photo-Multipliers (SiPMs) are increasingly becoming popular for discrete photon counting applications due to the wealth of advantages they offer over conventional photo-detectors such as photo-multiplier tubes and hybrid photo-diodes. SiPMs are used in variety of applications ranging from high energy physics and nuclear physics experiments to medical diagnostics. The gain of a SiPM is directly proportional to the difference between applied and breakdown voltage of the device. However, the breakdown voltage depends critically on the ambient temperature and has a large temperature co-efficient in the range of 40-60 mV/°C resulting in a typical gain variation of 3%-5%/°C [Dinu et al., in IEEE Nuclear Science Symposium, Medical Imaging Conference and 17th Room Temperature Semiconductor Detector Workshop (IEEE, 2010), p. 215]. We plan to use the SiPM as a replacement for PMT in the cosmic ray experiment (GRAPES-3) at Ooty [Gupta et al., Nucl. Instrum. Methods Phys. Res., Sect. A 540, 311 (2005)]. There the SiPMs will be operated in an outdoor environment subjected to temperature variation of about 15 °C over a day. A gain variation of more than 50% was observed for such large variations in the temperature. To stabilize the gain of the SiPM under such operating conditions, a low-cost, multi-channel programmable power supply (0-90 V) was designed that simultaneously provides the bias voltage to 16 SiPMs. The programmable power supply (PPS) was designed to automatically adjust the operating voltage for each channel with a built-in closed loop temperature feedback mechanism. The PPS provides bias voltage with a precision of 6 mV and measures the load current with a precision of 1 nA. Using this PPS, a gain stability of 0.5% for SiPM (Hamamatsu, S10931-050P) has been demonstrated over a wide temperature range of 15 °C. The design methodology of the PPS system, its validation, and the results of the tests carried out on the SiPM is presented in this

  11. Vertical channel free convection for a power law fluid with a constant heat flux

    SciTech Connect

    Irvine, T.F. Jr.; Schneider, W.J.

    1984-08-08

    The development of free convection in a purely viscous non-newtonian fluid under the influence of a uniform wall heat flux is investigated. A finite difference solution is presented of the velocity and temperature profiles for the flow of an Ostwald-de Waele (power law) fluid between two symmetrically heated vertical plates. The flow, temperature and heat transfer characteristics of the channel are presented in a dimensionless manner as related to the generalized Grashof and Prandtl numbers and the fully developed flow range is established. The numerical solutions for the developing flow are shown to approach two classical asymptotes - fully developed duct free convection at low Rayleigh numbers and two independent vertical plates at high Rayleigh numbers. A comparison is made between the results of this theoretical investigation and previously published analytical and experimental work on newtonian and non-newtonian fluids. The results and their application to engineering problems are discussed. The changes caused by the addition of soluble substances to water cause significant variations in the mean flow between the plates and in the outlet temperature.

  12. Mapping Spatial Distributions of Stream Power and Channel Change along a Gravel-Bed River in Northern Yellowstone

    NASA Astrophysics Data System (ADS)

    Lea, D. M.; Legleiter, C. J.

    2014-12-01

    Stream power represents the rate of energy expenditure along a river and can be calculated using topographic data acquired via remote sensing. This study used remotely sensed data and field measurements to quantitatively relate temporal changes in the form of Soda Butte Creek, a gravel-bed river in northeastern Yellowstone National Park, to stream power gradients along an 8 km reach. Aerial photographs from 1994-2012 and cross-section surveys were used to assess lateral channel mobility and develop a morphologic sediment budget for quantifying net sediment flux for a series of budget cells. A drainage area-to-discharge relationship and digital elevation model (DEM) developed from LiDAR data were used to obtain the discharge and slope values, respectively, needed to calculate stream power. Local and lagged relationships between mean stream power gradient at median peak discharge and volumes of erosion, deposition, and net sediment flux were quantified via spatial cross-correlation analyses. Similarly, autocorrelations of locational probabilities and sediment fluxes were used to examine spatial patterns of channel mobility and sediment transfer. Energy expended above critical stream power was calculated for each time period to relate the magnitude and duration of peak flows to the total volume of sediment eroded or deposited during each time increment. Our results indicated a lack of strong correlation between stream power gradients and sediment flux, which we attributed to the geomorphic complexity of the Soda Butte Creek watershed and the inability of our relatively simple statistical approach to link sediment dynamics expressed at a sub-budget cell scale to larger-scale driving forces such as stream power gradients. Future studies should compare the moderate spatial resolution techniques used in this study to very-high resolution data acquired from new fluvial remote sensing technologies to better understand the amount of error associated with stream power

  13. Age of Martian channels

    NASA Technical Reports Server (NTRS)

    Malin, M. C.

    1976-01-01

    The ages of large Martian channels have been studied by determining the relative abundances of craters superimposed on channels and adjacent terrains and by examining superposition relationships between channels and plains and mantle materials. The channels are extremely old, are spatially confined and temporally related to the ancient cratered terrain, and in many cases are related to the as yet poorly understood genetic processes of fretting and chaos formation. No evidence is found for recent channel activity.

  14. Mirrored serpentine flow channels for fuel cell

    SciTech Connect

    Rock, Jeffrey Allan

    2000-08-08

    A PEM fuel cell having serpentine flow field channels wherein the input/inlet legs of each channel border the input/inlet legs of the next adjacent channels in the same flow field, and the output/exit legs of each channel border the output/exit legs of the next adjacent channels in the same flow field. The serpentine fuel flow channels may be longer, and may contain more medial legs, than the serpentine oxidant flow channels.

  15. Multi-channel Data Acquisition System for a 500 m DC HTS Power Cable in Ishikari

    NASA Astrophysics Data System (ADS)

    Ivanov, Yury V.; Chikumoto, Noriko; Watanabe, Hirofumi; Takano, Hirohisa; Inoue, Noriyuki; Yamaguchi, Satarou

    Reduction of heat penetrating into the cryogenic region is the important method of optimization of superconducting devices. In the cases of short-range power transmission lines and compact HTS devices like magnets, the heat leakage through current leads is relatively large. In order to decrease this contribution, current leads equipped with Peltier elements can be used. The mentioned technology is being actively developed in the Chubu University. Commercial samples of Peltier current leads are installed at the terminals of 500-meter DC HTS cable in Ishikari (Hokkaido). This cable is designed for 5 kA. The inner conducting layer consists of 37 DI-BSCCO HTS tapes from Sumitomo Electric Industries, Ltd. with a critical current of 180 A; and the outer one consists of 35 tapes of the same type. Each end of the cable's tape is connected to the individual Peltier current lead. Accordingly, each of the two terminals is equipped with 72 Peltier current leads, 144 pieces in total. In order to examine behavior of the current leads in detail, each piece is supplied with two thermocouples; there are also voltage taps on feedthrough and on HTS tape end. In addition, current through Peltier current lead can be measured by means of individual current transformer. The hardware part of the data acquisition system includes four Keithley 3706A multimeters equipped with 60-channel model 3724 FET multiplexer cards. Therefore, 144 data blocks are formed. Furthermore, there are 72 measurements of a voltage drop across HTS tape. Sampling period is set to be 3 s. The program part of the data acquisition system was written using LabVIEW software solution (National Instruments Corp.).

  16. High-power single spatial mode AlGaAs channeled-substrate-planar semiconductor diode lasers for spaceborne communications

    NASA Technical Reports Server (NTRS)

    Connolly, J. C.; Carlin, D. B.; Ettenberg, M.

    1989-01-01

    A high power single spatial mode channeled substrate planar AlGaAs semiconductor diode laser was developed. The emission wavelength was optimized at 860 to 880 nm. The operating characteristics (power current, single spatial mode behavior, far field radiation patterns, and spectral behavior) and results of computer modeling studies on the performance of the laser are discussed. Reliability assessment at high output levels is included. Performance results on a new type of channeled substrate planar diode laser incorporating current blocking layers, grown by metalorganic chemical vapor deposition, to more effectively focus the operational current to the lasing region was demonstrated. The optoelectronic behavior and fabrication procedures for this new diode laser are discussed. The highlights include single spatial mode devices with up to 160 mW output at 8600 A, and quantum efficiencies of 70 percent (1 W/amp) with demonstrated operating lifetimes of 10,000 h at 50 mW.

  17. Mapping spatial patterns of stream power and channel change along a gravel-bed river in northern Yellowstone

    NASA Astrophysics Data System (ADS)

    Lea, Devin M.; Legleiter, Carl J.

    2016-01-01

    Stream power represents the rate of energy expenditure along a river and can be calculated using topographic data acquired via remote sensing or field surveys. This study sought to quantitatively relate temporal changes in the form of Soda Butte Creek, a gravel-bed river in northeastern Yellowstone National Park, to stream power gradients along an 8-km reach. Aerial photographs from 1994 to 2012 and ground-based surveys were used to develop a locational probability map and morphologic sediment budget to assess lateral channel mobility and changes in net sediment flux. A drainage area-to-discharge relationship and DEM developed from LiDAR data were used to obtain the discharge and slope values needed to calculate stream power. Local and lagged relationships between mean stream power gradient at median peak discharge and volumes of erosion, deposition, and net sediment flux were quantified via spatial cross-correlation analyses. Similarly, autocorrelations of locational probabilities and sediment fluxes were used to examine spatial patterns of sediment sources and sinks. Energy expended above critical stream power was calculated for each time period to relate the magnitude and duration of peak flows to the total volumetric change in each time increment. Collectively, we refer to these methods as the stream power gradient (SPG) framework. The results of this study were compromised by methodological limitations of the SPG framework and revealed some complications likely to arise when applying this framework to small, wandering, gravel-bed rivers. Correlations between stream power gradients and sediment flux were generally weak, highlighting the inability of relatively simple statistical approaches to link sub-budget cell-scale sediment dynamics to larger-scale driving forces such as stream power gradients. Improving the moderate spatial resolution techniques used in this study and acquiring very-high resolution data from recently developed methods in fluvial remote

  18. Single-channel kinetics of BK (Slo1) channels

    PubMed Central

    Geng, Yanyan; Magleby, Karl L.

    2014-01-01

    Single-channel kinetics has proven a powerful tool to reveal information about the gating mechanisms that control the opening and closing of ion channels. This introductory review focuses on the gating of large conductance Ca2+- and voltage-activated K+ (BK or Slo1) channels at the single-channel level. It starts with single-channel current records and progresses to presentation and analysis of single-channel data and the development of gating mechanisms in terms of discrete state Markov (DSM) models. The DSM models are formulated in terms of the tetrameric modular structure of BK channels, consisting of a central transmembrane pore-gate domain (PGD) attached to four surrounding transmembrane voltage sensing domains (VSD) and a large intracellular cytosolic domain (CTD), also referred to as the gating ring. The modular structure and data analysis shows that the Ca2+ and voltage dependent gating considered separately can each be approximated by 10-state two-tiered models with five closed states on the upper tier and five open states on the lower tier. The modular structure and joint Ca2+ and voltage dependent gating are consistent with a 50 state two-tiered model with 25 closed states on the upper tier and 25 open states on the lower tier. Adding an additional tier of brief closed (flicker states) to the 10-state or 50-state models improved the description of the gating. For fixed experimental conditions a channel would gate in only a subset of the potential number of states. The detected number of states and the correlations between adjacent interval durations are consistent with the tiered models. The examined models can account for the single-channel kinetics and the bursting behavior of gating. Ca2+ and voltage activate BK channels by predominantly increasing the effective opening rate of the channel with a smaller decrease in the effective closing rate. Ca2+ and depolarization thus activate by mainly destabilizing the closed states. PMID:25653620

  19. A high-power low-temperature air plasma generator with a divergent channel of the output electrode

    NASA Astrophysics Data System (ADS)

    Gadzhiev, M. Kh.; Isakaev, E. Kh.; Tyuftyaev, A. S.; Yusupov, D. I.

    2016-01-01

    We have developed and studied a powerful high-enthalpy (H ≥ 20 kJ/g) air plasma jet generator with a divergent channel of the output electrode, which belongs to the class of dc plasmatrons with a thermionic cathode. The plasma generator possesses an efficiency of about 80% and ensures the formation of slightly divergent (2± = 12°) plasma jet with diameter D = 50 mm and a mass-average temperature of 6000-9000 K.

  20. Mapping spatial patterns of stream power and channel change along a gravel-bed river in northern Yellowstone

    NASA Astrophysics Data System (ADS)

    Lea, Devin M.

    Stream power represents the rate of energy expenditure along a river and can be calculated using topographic data acquired via remote sensing or field surveys. This study used remote sensing and GIS tools along with field data to quantitatively relate temporal changes in the form of Soda Butte Creek, a gravel-bed river in northeastern Yellowstone National Park, to stream power gradients along an 8 km reach. Aerial photographs from 1994-2012 and cross-section surveys were used to develop a locational probability map and morphologic sediment budget to assess lateral channel mobility and changes in net sediment flux. A drainage area-to-discharge relationship and digital elevation model (DEM) developed from light detection and ranging (LiDAR) data were used to obtain the discharge and slope values needed to calculate stream power. Local and lagged relationships between mean stream power gradient at median peak discharge and volumes of erosion, deposition, and net sediment flux were quantified via spatial cross-correlation analyses. Similarly, autocorrelations of locational probabilities and sediment fluxes were used to examine spatial patterns of sediment sources and sinks. Energy expended above critical stream power was calculated for each time period to relate the magnitude and duration of peak flows to the total volumetric change in each time increment. Results indicated a lack of strong correlation between stream power gradients and sediment response, highlighting the geomorphic complexity of Soda Butte Creek and the inability of relatively simple statistical approaches to link sub-budget cell-scale sediment dynamics to larger-scale driving forces such as stream power gradients. Improving the moderate spatial resolution techniques used in this study and acquiring very-high resolution data from recently developed methods in fluvial remote sensing could help improve understanding of the spatial organization of stream power, sediment transport, and channel change in

  1. An Inductively Powered Scalable 32-Channel Wireless Neural Recording System-on-a-Chip for Neuroscience Applications

    PubMed Central

    Lee, Seung Bae; Lee, Hyung-Min; Kiani, Mehdi; Jow, Uei-Ming; Ghovanloo, Maysam

    2014-01-01

    We present an inductively powered 32-channel wireless integrated neural recording (WINeR) system-on-a-chip (SoC) to be ultimately used for one or more small freely behaving animals. The inductive powering is intended to relieve the animals from carrying bulky batteries used in other wireless systems, and enables long recording sessions. The WINeR system uses time-division multiplexing along with a novel power scheduling method that reduces the current in unused low-noise amplifiers (LNAs) to cut the total SoC power consumption. In addition, an on-chip high-efficiency active rectifier with optimized coils help improve the overall system power efficiency, which is controlled in a closed loop to supply stable power to the WINeR regardless of the coil displacements. The WINeR SoC has been implemented in a 0.5-µm standard complementary metal–oxide semiconductor process, measuring 4.9 × 3.3 mm2 and consuming 5.85 mW at ± 1.5 V when 12 out of 32 LNAs are active at any time by power scheduling. Measured input-referred noise for the entire system, including the receiver located at 1.2 m, is 4.95 µVrms in the 1 Hz~10 kHz range when the system is inductively powered with 7-cm separation between aligned coils. PMID:23850753

  2. The calculation of adjacent satellite interference for direct broadcast satellite systems

    NASA Astrophysics Data System (ADS)

    Dewell, R.; Siddiqi, S.

    1987-10-01

    In order to coordinate present and future in-orbit broadcast satellite systems, orbital slots and operating frequency bands must be allocated in such a way that the available broadcast spectrum is fully used, while the lowest level of interference between systems is maintained. The considerations affecting system planning and the factors determining broadcast transmission quality are reviewed, and a practical broadcast satellite system example is described. Copolarized and cross-polarized interfering signals are discussed, and the evaluation of received, cross-polarized, interfering power is considered. The calculation of minimum and maximum interference levels is addressed, and the acceptance criterion for adjacent-channel interference is discussed.

  3. A novel sub 20 nm single gate tunnel field effect transistor with intrinsic channel for ultra low power applications

    NASA Astrophysics Data System (ADS)

    Asthana, Pranav Kumar; Goswami, Yogesh; Ghosh, Bahniman

    2016-05-01

    We propose a nanoscale single gate ultra thin body intrinsic channel tunnel field effect transistor using the charge plasma concept for ultra low power applications. The characteristics of TFETs (having low leakage) are improved by junctionless TFETs through blending advantages of Junctionless FETs (with high on current). We further improved the characteristics, simultaneously simplifying the structure at a very low power rating using an InAs channel. We found that the proposed device structure has reduced short channel effects and parasitics and provides high speed operation even at a very low supply voltage with low leakage. Simulations resulted in IOFF of ˜ 9 × 10-16 A/μm, ION of ˜20 μA/μm, ION/IOFF of ˜2 × 1010, threshold voltage of 0.057 V, subthreshold slope of 7 mV/dec and DIBL of 86 mV/V for PolyGate/HfO2/InAs TFET at a temperature of 300 K, gate length of 20 nm, oxide thickness of 2 nm, film thickness of 10 nm, low-k spacer thickness of 10 nm and VDD of 0.2 V.

  4. A novel sub 20 nm single gate tunnel field effect transistor with intrinsic channel for ultra low power applications

    NASA Astrophysics Data System (ADS)

    Asthana, Pranav Kumar; Goswami, Yogesh; Ghosh, Bahniman

    2016-05-01

    We propose a nanoscale single gate ultra thin body intrinsic channel tunnel field effect transistor using the charge plasma concept for ultra low power applications. The characteristics of TFETs (having low leakage) are improved by junctionless TFETs through blending advantages of Junctionless FETs (with high on current). We further improved the characteristics, simultaneously simplifying the structure at a very low power rating using an InAs channel. We found that the proposed device structure has reduced short channel effects and parasitics and provides high speed operation even at a very low supply voltage with low leakage. Simulations resulted in IOFF of ∼ 9 × 10‑16 A/μm, ION of ∼20 μA/μm, ION/IOFF of ∼2 × 1010, threshold voltage of 0.057 V, subthreshold slope of 7 mV/dec and DIBL of 86 mV/V for PolyGate/HfO2/InAs TFET at a temperature of 300 K, gate length of 20 nm, oxide thickness of 2 nm, film thickness of 10 nm, low-k spacer thickness of 10 nm and VDD of 0.2 V.

  5. How to resolve microsecond current fluctuations in single ion channels: the power of beta distributions.

    PubMed

    Schroeder, Indra

    2015-01-01

    A main ingredient for the understanding of structure/function correlates of ion channels is the quantitative description of single-channel gating and conductance. However, a wealth of information provided from fast current fluctuations beyond the temporal resolution of the recording system is often ignored, even though it is close to the time window accessible to molecular dynamics simulations. This kind of current fluctuations provide a special technical challenge, because individual opening/closing or blocking/unblocking events cannot be resolved, and the resulting averaging over undetected events decreases the single-channel current. Here, I briefly summarize the history of fast-current fluctuation analysis and focus on the so-called "beta distributions." This tool exploits characteristics of current fluctuation-induced excess noise on the current amplitude histograms to reconstruct the true single-channel current and kinetic parameters. A guideline for the analysis and recent applications demonstrate that a construction of theoretical beta distributions by Markov Model simulations offers maximum flexibility as compared to analytical solutions. PMID:26368656

  6. Designing Effective Persuasive Systems Utilizing the Power of Entanglement: Communication Channel, Strategy & Affect

    ERIC Educational Resources Information Center

    Li, Haiqing

    2010-01-01

    With rapid advancements in information and communication technologies, computer-mediated communication channels such as email, web, mobile smart-phones with SMS, social networking websites (Facebook), multimedia websites, and OEM devices provide users with multiple technology choices to seek information. However, no study has compared the…

  7. Ultralow power complementary inverter circuits using axially doped p- and n-channel Si nanowire field effect transistors

    NASA Astrophysics Data System (ADS)

    van, Ngoc Huynh; Lee, Jae-Hyun; Whang, Dongmok; Kang, Dae Joon

    2016-06-01

    We have successfully synthesized axially doped p- and n-type regions on a single Si nanowire (NW). Diodes and complementary metal-oxide-semiconductor (CMOS) inverter devices using single axial p- and n-channel Si NW field-effect transistors (FETs) were fabricated. We show that the threshold voltages of both p- and n-channel Si NW FETs can be lowered to nearly zero by effectively controlling the doping concentration. Because of the high performance of the p- and n-type Si NW channel FETs, especially with regard to the low threshold voltage, the fabricated NW CMOS inverters have a low operating voltage (<3 V) while maintaining a high voltage gain (~6) and ultralow static power dissipation (<=0.3 pW) at an input voltage of +/-3 V. This result offers a viable way for the fabrication of a high-performance high-density logic circuit using a low-temperature fabrication process, which makes it suitable for flexible electronics.We have successfully synthesized axially doped p- and n-type regions on a single Si nanowire (NW). Diodes and complementary metal-oxide-semiconductor (CMOS) inverter devices using single axial p- and n-channel Si NW field-effect transistors (FETs) were fabricated. We show that the threshold voltages of both p- and n-channel Si NW FETs can be lowered to nearly zero by effectively controlling the doping concentration. Because of the high performance of the p- and n-type Si NW channel FETs, especially with regard to the low threshold voltage, the fabricated NW CMOS inverters have a low operating voltage (<3 V) while maintaining a high voltage gain (~6) and ultralow static power dissipation (<=0.3 pW) at an input voltage of +/-3 V. This result offers a viable way for the fabrication of a high-performance high-density logic circuit using a low-temperature fabrication process, which makes it suitable for flexible electronics. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01040g

  8. A Power-Efficient Clustering Protocol for Coal Mine Face Monitoring with Wireless Sensor Networks Under Channel Fading Conditions.

    PubMed

    Ren, Peng; Qian, Jiansheng

    2016-01-01

    This study proposes a novel power-efficient and anti-fading clustering based on a cross-layer that is specific to the time-varying fading characteristics of channels in the monitoring of coal mine faces with wireless sensor networks. The number of active sensor nodes and a sliding window are set up such that the optimal number of cluster heads (CHs) is selected in each round. Based on a stable expected number of CHs, we explore the channel efficiency between nodes and the base station by using a probe frame and the joint surplus energy in assessing the CH selection. Moreover, the sending power of a node in different periods is regulated by the signal fade margin method. The simulation results demonstrate that compared with several common algorithms, the power-efficient and fading-aware clustering with a cross-layer (PEAFC-CL) protocol features a stable network topology and adaptability under signal time-varying fading, which effectively prolongs the lifetime of the network and reduces network packet loss, thus making it more applicable to the complex and variable environment characteristic of a coal mine face. PMID:27338380

  9. A Power-Efficient Clustering Protocol for Coal Mine Face Monitoring with Wireless Sensor Networks Under Channel Fading Conditions

    PubMed Central

    Ren, Peng; Qian, Jiansheng

    2016-01-01

    This study proposes a novel power-efficient and anti-fading clustering based on a cross-layer that is specific to the time-varying fading characteristics of channels in the monitoring of coal mine faces with wireless sensor networks. The number of active sensor nodes and a sliding window are set up such that the optimal number of cluster heads (CHs) is selected in each round. Based on a stable expected number of CHs, we explore the channel efficiency between nodes and the base station by using a probe frame and the joint surplus energy in assessing the CH selection. Moreover, the sending power of a node in different periods is regulated by the signal fade margin method. The simulation results demonstrate that compared with several common algorithms, the power-efficient and fading-aware clustering with a cross-layer (PEAFC-CL) protocol features a stable network topology and adaptability under signal time-varying fading, which effectively prolongs the lifetime of the network and reduces network packet loss, thus making it more applicable to the complex and variable environment characteristic of a coal mine face. PMID:27338380

  10. Flow tests of a single fuel element coolant channel for a compact fast reactor for space power

    NASA Technical Reports Server (NTRS)

    Springborn, R. H.

    1971-01-01

    Water flow tests were conducted on a single-fuel-element cooling channel for a nuclear concept to be used for space power. The tests established a method for measuring coolant flow rate which is applicable to water flow testing of a complete mockup of the reference reactor. The inlet plenum-to-outlet plenum pressure drop, which approximates the overall core pressure drop, was measured and correlated with flow rate. This information can be used for reactor coolant flow and heat transfer calculations. An analytical study of the flow characteristics was also conducted.

  11. 28. TOP VIEW OF CIRCUIT BREAKER ADJACENT TO BRIDGE, CATENARY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. TOP VIEW OF CIRCUIT BREAKER ADJACENT TO BRIDGE, CATENARY ANCHOR BRIDGE 310, COS COB POWER PLANT - New York, New Haven & Hartford Railroad, Automatic Signalization System, Long Island Sound shoreline between Stamford & New Haven, Stamford, Fairfield County, CT

  12. Design of a low power 10 bit 300 ksps multi-channel SAR ADC for wireless sensor network applications

    NASA Astrophysics Data System (ADS)

    Hui, Hong; Shiliang, Li; Tao, Zhou

    2015-04-01

    This paper presents a low power 10 bit 300 ksps successive approximation register analog-to-digital converter (SAR ADC) which is applied in wireless sensor network (WSN) applications. A single ended energy-saving split capacitor DAC array and a latch comparator with a rail to rail input stage are utilized to implement the ADC, which can reduce power dissipation while expanding the full scale input range and improve the signal-to-noise ratio (SNR). For power optimization the supply voltage of the SAR ADC is designed to be as low as 2 V. Four analog input channels are designed which make the ADC more suitable for WSN applications. The prototype circuit is fabricated using 3.3 V, 0.35 μm 2P4M CMOS technology and occupies an active chip area of 1.23 mm2. The test results show that the power dissipation is only 200 μW at a 2 V power supply and a sampling rate of 166 ksps. The calculated SNR is 58.25 dB, the ENOB is 9.38 bit and the FOM is 4.95 pJ/conversion-step. Project supported by the National Natural Science Foundation of China (No. 61107025) and the Key Innovation Team Project of Zhejiang Province (No. 2010R50010).

  13. Designing Effective Persuasive Systems Utilizing the Power of Entanglement: Communication Channel, Strategy and Affect

    NASA Astrophysics Data System (ADS)

    Li, Haiqing; Chatterjee, Samir

    With rapid advances in information and communication technology, computer-mediated communication (CMC) technologies are utilizing multiple IT platforms such as email, websites, cell-phones/PDAs, social networking sites, and gaming environments. However, no studies have compared the effectiveness of a persuasive system using such alternative channels and various persuasive techniques. Moreover, how affective computing impacts the effectiveness of persuasive systems is not clear. This study proposes (1) persuasive technology channels in combination with persuasive strategies will have different persuasive effectiveness; (2) Adding positive emotion to a message that leads to a better overall user experience could increase persuasive effectiveness. The affective computing or emotion information was added to the experiment using emoticons. The initial results of a pilot study show that computer-mediated communication channels along with various persuasive strategies can affect the persuasive effectiveness to varying degrees. These results also shows that adding a positive emoticon to a message leads to a better user experience which increases the overall persuasive effectiveness of a system.

  14. Ultralow power complementary inverter circuits using axially doped p- and n-channel Si nanowire field effect transistors.

    PubMed

    Van, Ngoc Huynh; Lee, Jae-Hyun; Whang, Dongmok; Kang, Dae Joon

    2016-06-01

    We have successfully synthesized axially doped p- and n-type regions on a single Si nanowire (NW). Diodes and complementary metal-oxide-semiconductor (CMOS) inverter devices using single axial p- and n-channel Si NW field-effect transistors (FETs) were fabricated. We show that the threshold voltages of both p- and n-channel Si NW FETs can be lowered to nearly zero by effectively controlling the doping concentration. Because of the high performance of the p- and n-type Si NW channel FETs, especially with regard to the low threshold voltage, the fabricated NW CMOS inverters have a low operating voltage (<3 V) while maintaining a high voltage gain (∼6) and ultralow static power dissipation (≤0.3 pW) at an input voltage of ±3 V. This result offers a viable way for the fabrication of a high-performance high-density logic circuit using a low-temperature fabrication process, which makes it suitable for flexible electronics. PMID:27240692

  15. Fundamental studies on initiation and evolution of multi-channel discharges and their application to next generation pulsed power machines.

    SciTech Connect

    Schwarz, Jens; Savage, Mark E.; Lucero, Diego Jose; Jaramillo, Deanna M.; Seals, Kelly Gene; Pitts, Todd Alan; Hautzenroeder, Brenna M.; Laine, Mark Richard; Karelitz, David B.; Porter, John L.

    2014-09-01

    Future pulsed power systems may rely on linear transformer driver (LTD) technology. The LTD's will be the building blocks for a driver that can deliver higher current than the Z-Machine. The LTD's would require tens of thousands of low inductance ( %3C 85nH), high voltage (200 kV DC) switches with high reliability and long lifetime ( 10 4 shots). Sandia's Z-Machine employs 36 megavolt class switches that are laser triggered by a single channel discharge. This is feasible for tens of switches but the high inductance and short switch life- time associated with the single channel discharge are undesirable for future machines. Thus the fundamental problem is how to lower inductance and losses while increasing switch life- time and reliability. These goals can be achieved by increasing the number of current-carrying channels. The rail gap switch is ideal for this purpose. Although those switches have been extensively studied during the past decades, each effort has only characterized a particular switch. There is no comprehensive understanding of the underlying physics that would allow predictive capability for arbitrary switch geometry. We have studied rail gap switches via an extensive suite of advanced diagnostics in synergy with theoretical physics and advanced modeling capability. Design and topology of multichannel switches as they relate to discharge dynamics are investigated. This involves electrically and optically triggered rail gaps, as well as discrete multi-site switch concepts.

  16. A novel 2 T P-channel nano-crystal memory for low power/high speed embedded NVM applications

    NASA Astrophysics Data System (ADS)

    Junyu, Zhang; Yong, Wang; Jing, Liu; Manhong, Zhang; Zhongguang, Xu; Zongliang, Huo; Ming, Liu

    2012-08-01

    We introduce a novel 2 T P-channel nano-crystal memory structure for low power and high speed embedded non-volatile memory (NVM) applications. By using the band-to-band tunneling-induced hot-electron (BTBTIHE) injection scheme, both high-speed and low power programming can be achieved at the same time. Due to the use of a select transistor, the “erased states" can be set to below 0 V, so that the periphery HV circuit (high-voltage generating and management) and read-out circuit can be simplified. Good memory cell performance has also been achieved, including a fast program/erase (P/E) speed (a 1.15 V memory window under 10 μs program pulse), an excellent data retention (only 20% charge loss for 10 years). The data shows that the device has strong potential for future embedded NVM applications.

  17. MHD mixed convection analysis in an open channel by obstructed Poiseuille flow of non-Newtonian power law fluid

    NASA Astrophysics Data System (ADS)

    Rabbi, Khan Md.; Rakib, Tawfiqur; Das, Sourav; Mojumder, Satyajit; Saha, Sourav

    2016-07-01

    This paper demonstrates magneto-hydrodynamic (MHD) mixed convection flow through a channel with a rectangular obstacle at the entrance region using non-Newtonian power law fluid. The obstacle is kept at uniformly high temperature whereas the inlet and top wall of the channel are maintained at a temperature lower than obstacle temperature. Poiseuille flow is implemented as the inlet velocity boundary condition. Grid independency test and code validation are performed to justify the computational accuracy before solving the present problem. Galerkin weighted residual method has been appointed to solve the continuity, momentum and energy equations. The problem has been solved for wide range of pertinent parameters like Richardson number (Ri = 0.1 - 10) at a constant Reynolds number (Re = 100), Hartmann number (Ha = 0 - 100), power index (n = 0.6 - 1.6). The flow and thermal field have been thoroughly discussed through streamline and isothermal lines respectively. The heat transfer performance of the given study has been illustrated by average Nusselt number plots. It is observed that increment of Hartmann number (Ha) tends to decrease the heat transfer rate up to a critical value (Ha = 20) and then let increase the heat transfer performance. Thus maximum heat transfer rate has been recorded for higher Hartmann number and Rayleigh number in case of pseudo-plastic (n = 0.6) non-Newtonian fluid flow.

  18. Seabed drifter movement in San Diego Bay and adjacent waters

    NASA Astrophysics Data System (ADS)

    Hammond, Robert R.; Wallace, William J.

    1982-06-01

    The seabed drifter has been used successfully to provide valuable information in many estuarine and open sea environments. It was therefore selected for use in the San Diego area. Five hundred drifters were released in San Diego Bay and adjacent ocean waters to delineate bottom flow patterns. Four significant bottom drift regimes are differentiated: off-coastal, main bay channel, open and semi-enclosed docking basins. Mean residual bottom drift ranged between 0·17km day -1 off the coast to essentially zero in the docking basins. Off-coast drifter results (31% recovery) showed a persistent northmoving bottom current with shallow near-coast drift distances between 4 and 25 km. This nearshore north moving bottom current appears to cause a net bottom water inflow into the main San Diego Bay channel (44% recovery). In the open bay a reverse trend was observed from the 16% of the drifters recovered. At the head of the estuary, evaporative densification is believed to occur, with the heavier water sinking and moving outward, towards the estuary mouth, resulting in an area of opposing bottom water currents. In this area San Diego Gas and Electric power plant takes in an average 150 million gallons of cooling water daily which, discharged as warm surface water, is suggested as the surface divergence mode required to reconcile the observed flow. With the three San Diego Bay electric power plants utilizing more than 5% of the maximum tidal prism for cooling purposes, this flow may play a major role in the overall bay circulation and requires quantitative investigation.

  19. A high-efficiency, low-noise power solution for a dual-channel GNSS RF receiver

    NASA Astrophysics Data System (ADS)

    Jian, Shi; Taishan, Mo; Jianlian, Le; Yebing, Gan; Chengyan, Ma; Tianchun, Ye

    2012-08-01

    A high-efficiency low-noise power solution for a dual-channel GNSS RF receiver is presented. The power solution involves a DC—DC buck converter and a followed low-dropout regulator (LDO). The pulse-width-modulation (PWM) control method is adopted for better noise performance. An improved low-power high-frequency PWM control circuit is proposed, which halves the average quiescent current of the buck converter to 80 μA by periodically shutting down the OTA. The size of the output stage has also been optimized to achieve high efficiency under a light load condition. In addition, a novel soft-start circuit based on a current limiter has been implemented to avoid inrush current. Fabricated with commercial 180-nm CMOS technology, the DC—DC converter achieves a peak efficiency of 93.1% under a 2 MHz working frequency. The whole receiver consumes only 20.2 mA from a 3.3 V power supply and has a noise figure of 2.5 dB.

  20. A Novel Dynamic Channel Access Scheme Using Overlap FFT Filter-Bank for Cognitive Radio

    NASA Astrophysics Data System (ADS)

    Tanabe, Motohiro; Umehira, Masahiro; Ishihara, Koichi; Takatori, Yasushi

    An OFDMA based channel access scheme is proposed for dynamic spectrum access to utilize frequency spectrum efficiently. Though the OFDMA based scheme is flexible enough to change the bandwidth and channel of the transmitted signals, the OFDMA signal has large PAPR (Peak to Average Power Ratio). In addition, if the OFDMA receiver does not use a filter to extract sub-carriers before FFT (Fast Fourier Transform) processing, the designated sub-carriers suffer large interference from the adjacent channel signals in the FFT processing on the receiving side. To solve the problems such as PAPR and adjacent channel interference encountered in the OFDMA based scheme, this paper proposes a novel dynamic channel access scheme using overlap FFT filter-bank based on single carrier modulation. It also shows performance evaluation results of the proposed scheme by computer simulation.

  1. Characterization of annealing of Co-60 gamma-ray damage in N-channel power MOSFETs

    NASA Astrophysics Data System (ADS)

    Bendada, E.; Raïs, K.; Mialhe, P.

    The purpose of this work was to characterize the annealing of Gamma-ray damage in power MOSFETs. Parameters degradation for a dose rate of 103.8 rad min-1 are presented. Temperature annealing effects, at 100°C, are discussed and analyzed by the evolution of the density trapped oxide charges and trapped interface charges.

  2. Self-powered competitive immunosensor driven by biofuel cell based on hollow-channel paper analytical devices.

    PubMed

    Li, Shuai; Wang, Yanhu; Ge, Shenguang; Yu, Jinghua; Yan, Mei

    2015-09-15

    A mediator-less and compartment-less glucose/O2 enzymatic biofuel cell (BFC) was introduced into microfluidic paper-based analytical devices (μ-PADs) that relies on flow in hollow channels with silver nanoparticles/graphene modified paper electrode as the anodic and cathodic substrate, to implement self-powered sensitive carcinoembryonic antigen (CEA) detection. Glucose dehydrogenase (GDH)-gold nanoparticles bioconjugate modified with CEA acted as a biocatalyst for enhancing glucose oxidation in the bioanode, as well as the transducing enzyme for signaling magnification. Similarly, nanoporous PtNi/bilirubin oxidase (BOD) acted as a biocatalyst for enhancing O2 reduction in the biocathode. With an increase in the concentration of CEA, the amount of CEA-Au-GDH bioconjugate on bioanode decreases, thus leading to the lower output of the as-prepared BFC. This proposed BFC-based self-powered immunosensor for CEA possessed largely increased linear detection range from 1 pg mL(-1) to 0.5 μg mL(-)(1) with a detection limit of 0.7 pg mL(-)(1). The proposed BFC-based self-powered immunosensor shows high sensitivity, stability, and reproducibility and can become a promising platform for other protein detection.

  3. Self-powered competitive immunosensor driven by biofuel cell based on hollow-channel paper analytical devices.

    PubMed

    Li, Shuai; Wang, Yanhu; Ge, Shenguang; Yu, Jinghua; Yan, Mei

    2015-09-15

    A mediator-less and compartment-less glucose/O2 enzymatic biofuel cell (BFC) was introduced into microfluidic paper-based analytical devices (μ-PADs) that relies on flow in hollow channels with silver nanoparticles/graphene modified paper electrode as the anodic and cathodic substrate, to implement self-powered sensitive carcinoembryonic antigen (CEA) detection. Glucose dehydrogenase (GDH)-gold nanoparticles bioconjugate modified with CEA acted as a biocatalyst for enhancing glucose oxidation in the bioanode, as well as the transducing enzyme for signaling magnification. Similarly, nanoporous PtNi/bilirubin oxidase (BOD) acted as a biocatalyst for enhancing O2 reduction in the biocathode. With an increase in the concentration of CEA, the amount of CEA-Au-GDH bioconjugate on bioanode decreases, thus leading to the lower output of the as-prepared BFC. This proposed BFC-based self-powered immunosensor for CEA possessed largely increased linear detection range from 1 pg mL(-1) to 0.5 μg mL(-)(1) with a detection limit of 0.7 pg mL(-)(1). The proposed BFC-based self-powered immunosensor shows high sensitivity, stability, and reproducibility and can become a promising platform for other protein detection. PMID:25880834

  4. Propagation and amplification of microwave radiation in a plasma channel created in gas by a high-power femtosecond UV laser pulse

    NASA Astrophysics Data System (ADS)

    Bogatskaya, A. V.; Volkova, E. A.; Popov, A. M.; Smetanin, I. V.

    2016-02-01

    The time evolution of a nonequilibrium plasma channel created in a noble gas by a high-power femtosecond KrF laser pulse is investigated. It is shown that such a channel possesses specific electrodynamic properties and can be used as a waveguide for efficient transportation and amplification of microwave pulses. The propagation of microwave radiation in a plasma waveguide is analyzed by self-consistently solving (i) the Boltzmann kinetic equation for the electron energy distribution function at different spatial points and (ii) the wave equation in the parabolic approximation for a microwave pulse transported along the plasma channel.

  5. A simple packet retransmission strategy for throughput and delay enhancement on power line communication channels

    SciTech Connect

    Onunga, J.O. ); Donaldson, R.W. . Dept. of Electrical Engineering)

    1993-07-01

    A new, simple, and effective communication protocol is developed and evaluated for use on power line distribution networks. The protocol involves retransmission of unacknowledged packets, which are sent in either single or multiple (N) copies in accordance with estimates of communication link quality. Multiple packet copies can be code combined at the receiver, using majority voting on each bit position, to reduce packet error rates. Adaptive link quality estimates are based on the receipt or absence of positive acknowledgements. Information throughput efficiency is calculated and N optimized in terms of system variables. Performance benefits of code combining are clearly demonstrated. The algorithm was implemented and tested using a five-station intrabuilding power line communications network operating at 1.2, 2.4, 4.8 and 9.6 kbit/s data rate. Substantial throughput and delay improvement occurred on poor quality links, without degrading performance on good links.

  6. Performance enhancement using forward error correction on power line communication channels

    SciTech Connect

    Chan, M.H.L. ); Friedman, D.; Donaldson, R.W. )

    1994-04-01

    The use of forward error correction (FEC) coding is investigated, to enhance communication throughput and reliability on noisy power line networks. Rate one-half self-orthogonal convolutional codes are considered. These codes are known to be effective in other environments, and can be decoded inexpensively in real-time using majority logic decoders. Extensive bit and packet error rate tests were conducted on actual, noisy in-building power line links. Coding gains of 15 dB were observed at 10[sup [minus]3] decoded bit error rates. A self-orthogonal (2, 1, 6) convolutional code with interleaving to degree 7 was particularly effective, and was implemented as a VLSI microelectronic chip. Its use improved data throughput and packet error rates substantially, at data transmission rates of 9,600 bits/s.

  7. Channel Temperature Model for Microwave AlGaN/GaN HEMTs on SiC and Sapphire MMICs in High Power, High Efficiency SSPAs

    NASA Technical Reports Server (NTRS)

    Freeman, Jon C.

    2004-01-01

    A key parameter in the design trade-offs made during AlGaN/GaN HEMTs development for microwave power amplifiers is the channel temperature. An accurate determination can, in general, only be found using detailed software; however, a quick estimate is always helpful, as it speeds up the design cycle. This paper gives a simple technique to estimate the channel temperature of a generic microwave AlGaN/GaN HEMT on SiC or Sapphire, while incorporating the temperature dependence of the thermal conductivity. The procedure is validated by comparing its predictions with the experimentally measured temperatures in microwave devices presented in three recently published articles. The model predicts the temperature to within 5 to 10 percent of the true average channel temperature. The calculation strategy is extended to determine device temperature in power combining MMICs for solid-state power amplifiers (SSPAs).

  8. Vertical-channel free convection with a power-law fluid

    SciTech Connect

    Irvine, T.F. Jr.; Wu, K.C.; Schneider, W.J.

    1982-01-01

    A finite-difference solution is presented of the velocity and temperature fields for the flow of an Ostwald-de-Waele (power law) fluid between two vertical isothermal parallel plates under the influence of free convection. Two quantities are of particular interest: the total heat transferred from the plates and the average velocity between the plates. Although these quantities can be presented in a dimensionless manner as related to the generalized Grashof and Prandtl numbers, there is an important difference compared to the similar problem involving Newtonian fluids. In the present case, the generalized Prandtl number is not a fluid property but contains a geometric factor and thus the geometry of the system must be specified before the Prandtl number is fixed. The results and the manner in which they can be used are illustrated by a numerical example.

  9. On-line testing of calibration of process instrumentation channels in nuclear power plants. Phase 2, Final report

    SciTech Connect

    Hashemian, H.M.

    1995-11-01

    The nuclear industry is interested in automating the calibration of process instrumentation channels; this report provides key results of one of the sponsored projects to determine the validity of automated calibrations. Conclusion is that the normal outputs of instrument channels in nuclear plants can be monitored over a fuel cycle while the plant is operating to determine calibration drift in the field sensors and associated signal conversion and signal conditioning equipment. The procedure for on-line calibration tests involving calculating the deviation of each instrument channel from the best estimate of the process parameter that the instrument is measuring. Methods were evaluated for determining the best estimate. Deviation of each signal from the best estimate is updated frequently while the plant is operating and plotted vs time for entire fuel cycle, thereby providing time history plots that can reveal channel drift and other anomalies. Any instrument channel that exceeds allowable drift or channel accuracy band is then scheduled for calibration during a refueling outage or sooner. This provides calibration test results at the process operating point, one of the most critical points of the channel operation. This should suffice for most narrow-range instruments, although the calibration of some instruments can be verified at other points throughout their range. It should be pointed out that the calibration of some process signals such as the high pressure coolant injection flow in BWRs, which are normally off- scale during plant operation, can not be tested on-line.

  10. Design and characterization of electrically self-isolated GaN-on-Si junctionless fin-shaped-channel field-effect transistor with higher cost-effectiveness for low-power applications

    NASA Astrophysics Data System (ADS)

    Lee, Seongmin; Lee, Jeongmin; Cho, Seongjae

    2015-08-01

    A GaN-on-Si junctionless FET with a feasible structure is suggested and simulated. A silicon-on-insulator channel is replaced by a GaN-on-Si channel in the proposed device. The GaN-on-Si heterostructure forms an electrically self-isolated channel owing to its large band offset. Two- and three-dimensional (2D and 3D) device simulations were cooperatively performed to optimize the device in terms of gate length, channel thickness, channel doping concentration, and substrate concentration, targeting low-power applications.

  11. Erosion Control and Recultivation Measures at a Headrace Channel of a Hydroelectric Power Plant using Different Combined Soil Bioengineering Techniques

    NASA Astrophysics Data System (ADS)

    Obriejetan, M.; Florineth, F.; Rauch, H. P.

    2012-04-01

    vegetation properties are studied by setting up comparative test plots at a field study site located at a headrace channel of a hydroelectric power plant. Different vegetational parameters such as basal coverage, species richness, species composition, abundance/dominance values by using a refined Braun-Blanquet cover estimation scale were collected as well as local environmental properties. Results during the first vegetation period show distinct effects of geotextiles especially on overall vegetation coverage and grasses-herbs-ratio. Geotextile supported plots show 20% higher overall coverage but lower amount of herbs after three months of vegetation growth compared to control plots without installation of auxiliary materials. Furthermore coir blankets reveal higher penetration resistance for seed leaves of herbal plants compared to coir nettings. Hence technical erosion protection products, biological components and it's combination have to be closely coordinated in order to achieve specified revegetation objectives and meet long-term functionality.

  12. Modulation techniques for power and spectrally efficient SATCOM systems

    NASA Technical Reports Server (NTRS)

    Feher, Kamilo

    1992-01-01

    Research on modulation/demodulation (modem) techniques which leads to improved power and spectrally efficient digital satellite communications systems is proposed. A new family of digital modems, which enable satellite earth station and satellite transponder operation with fully saturated high power amplifiers (HPA) in an adjacent channel environment, having an optimized P(e) = f(E(sub b)/N(sub o)) performance will be introduced and analyzed.

  13. Impact-parameter dependent stopping powers for axially channeled and semichanneled MeV He ions in GaAs:Er

    SciTech Connect

    Kido, Y.; Ikeda, A.; Yamamoto, Y. ); Nakata, J. ); Yamaguchi, H.; Takahei, K. )

    1994-05-15

    We have investigated the impact-parameter dependence of stopping powers for axially channeled and semichanneled MeV He ions in Er-sheet-doped GaAs epitaxial layers grown by molecular-beam epitaxy. Ion channeling analysis using 2.0 MeV He[sup +] coupled with the observation by transmission-electron microscope has revealed the formation of fine ErAs clusters, whose lattice constant shrinks and coincides exactly with that of the GaAs host. Thus the Er atoms take the position corresponding to the tetrahedral interstitial site of the GaAs lattice. The Er peak energies in the backscattering spectra strongly depend on the impact-parameter dependent stopping powers, in particular for the incidence along [110] and the directions slightly tilted from [110] and [100]. We divide the stopping power into two parts---contributions from outer electrons and from inner electrons of GaAs. The former is calculated from the dielectric response theory. For the latter, we consider four types of stopping powers dependent upon impact parameter; (1) Dettmann-Robinson theory, (2) the binary-encounter model, (3) the binary encounter combined with the local-density approximation, and (4) the extended-local-electron-density model. The Er peak energies observed are well reproduced employing model (3).

  14. Electro-osmotic flow of power-law fluid and heat transfer in a micro-channel with effects of Joule heating and thermal radiation

    NASA Astrophysics Data System (ADS)

    Shit, G. C.; Mondal, A.; Sinha, A.; Kundu, P. K.

    2016-11-01

    A mathematical model has been developed for studying the electro-osmotic flow and heat transfer of bio-fluids in a micro-channel in the presence of Joule heating effects. The flow of bio-fluid is governed by the non-Newtonian power-law fluid model. The effects of thermal radiation and velocity slip condition have been examined in the case of hydrophobic channel. The Poisson-Boltzmann equation governing the electrical double layer field and a body force generated by the applied electric potential field are taken into consideration. The results presented here pertain to the case where the height of the channel is much greater than the thickness of electrical double layer comprising the Stern and diffuse layers. The expressions for flow characteristics such as velocity, temperature, shear stress and Nusselt number have been derived analytically under the purview of the present model. The results estimated on the basis of the data available in the existing scientific literatures are presented graphically. The effects of thermal radiation have an important bearing on the therapeutic procedure of hyperthermia, particularly in understanding the heat transfer in micro-channel in the presence of electric potential. The dimensionless Joule heating parameter has a reducing impact on Nusselt number for both pseudo-plastic and dilatant fluids, nevertheless its impact on Nusselt number is more pronounced for dilatant fluid. Furthermore, the effect of viscous dissipation has a significant role in controlling heat transfer and should not be neglected.

  15. One bit/s/Hz Spectrally Efficient Transmission for an Eight-Channel NRZ-Modulated DWDM System

    NASA Astrophysics Data System (ADS)

    Vij, Robin; Sharma, Neeraj

    2016-03-01

    The core of the global telecommunication network consists of wavelength-division multiplexed (WDM) optical transmission systems. WDM is the technology of choice as it allows for a high spectral efficiency. We propose an effective way to counter the nonlinearities like four-wave mixing and cross-phase modulation to achieve the spectral efficiency of 1 bit/s/Hz using non-return-to-zero (NRZ) modulation format. We use the concept of non-uniform channel spacing and non-uniform power assignment between adjacent channels of the WDM system. We have simulated an eight-channel WDM lightwave system with bit rates of 10 and 25 Gbit/s.

  16. Encoding of rat working memory by power of multi-channel local field potentials via sparse non-negative matrix factorization.

    PubMed

    Liu, Xu; Liu, Tiao-Tiao; Bai, Wen-Wen; Yi, Hu; Li, Shuang-Yan; Tian, Xin

    2013-06-01

    Working memory plays an important role in human cognition. This study investigated how working memory was encoded by the power of multi-channel local field potentials (LFPs) based on sparse nonnegative matrix factorization (SNMF). SNMF was used to extract features from LFPs recorded from the prefrontal cortex of four Sprague-Dawley rats during a memory task in a Y maze, with 10 trials for each rat. Then the power-increased LFP components were selected as working memory-related features and the other components were removed. After that, the inverse operation of SNMF was used to study the encoding of working memory in the time-frequency domain. We demonstrated that theta and gamma power increased significantly during the working memory task. The results suggested that postsynaptic activity was simulated well by the sparse activity model. The theta and gamma bands were meaningful for encoding working memory.

  17. First experimental demonstration of 6Gb/s real-time optical OFDM transceivers incorporating channel estimation and variable power loading.

    PubMed

    Giddings, R P; Jin, X Q; Tang, J M

    2009-10-26

    The fastest ever 6Gb/s real-time FPGA-based optical orthogonal frequency division multiplexing (OOFDM) transceivers utilizing channel estimation are experimentally demonstrated, for the first time, with variable power loading being incorporated to effectively compensate for the rapid system frequency response roll-off effect. The implemented transceivers are constructed entirely from off-the-shelf components and incorporate crucial functionalities of on-line performance monitoring and live optimization of key parameters including signal clipping, subcarrier power and operating conditions of directly modulated DFB lasers (DMLs). Real-time end-to-end transmission of a 6Gb/s 16-QAM-encoded OOFDM signal over 300m OM1 multi-mode fiber with a power penalty of 0.5dB is successfully achieved in an intensity-modulation and direct-detection system employing a DML. PMID:19997193

  18. First experimental demonstration of 6Gb/s real-time optical OFDM transceivers incorporating channel estimation and variable power loading.

    PubMed

    Giddings, R P; Jin, X Q; Tang, J M

    2009-10-26

    The fastest ever 6Gb/s real-time FPGA-based optical orthogonal frequency division multiplexing (OOFDM) transceivers utilizing channel estimation are experimentally demonstrated, for the first time, with variable power loading being incorporated to effectively compensate for the rapid system frequency response roll-off effect. The implemented transceivers are constructed entirely from off-the-shelf components and incorporate crucial functionalities of on-line performance monitoring and live optimization of key parameters including signal clipping, subcarrier power and operating conditions of directly modulated DFB lasers (DMLs). Real-time end-to-end transmission of a 6Gb/s 16-QAM-encoded OOFDM signal over 300m OM1 multi-mode fiber with a power penalty of 0.5dB is successfully achieved in an intensity-modulation and direct-detection system employing a DML.

  19. Detergent-free isolation, characterization, and functional reconstitution of a tetrameric K+ channel: The power of native nanodiscs

    PubMed Central

    Dörr, Jonas M.; Koorengevel, Martijn C.; Schäfer, Marre; Prokofyev, Alexander V.; Scheidelaar, Stefan; van der Cruijsen, Elwin A. W.; Dafforn, Timothy R.; Baldus, Marc; Killian, J. Antoinette

    2014-01-01

    A major obstacle in the study of membrane proteins is their solubilization in a stable and active conformation when using detergents. Here, we explored a detergent-free approach to isolating the tetrameric potassium channel KcsA directly from the membrane of Escherichia coli, using a styrene-maleic acid copolymer. This polymer self-inserts into membranes and is capable of extracting membrane patches in the form of nanosize discoidal proteolipid particles or “native nanodiscs.” Using circular dichroism and tryptophan fluorescence spectroscopy, we show that the conformation of KcsA in native nanodiscs is very similar to that in detergent micelles, but that the thermal stability of the protein is higher in the nanodiscs. Furthermore, as a promising new application, we show that quantitative analysis of the co-isolated lipids in purified KcsA-containing nanodiscs allows determination of preferential lipid–protein interactions. Thin-layer chromatography experiments revealed an enrichment of the anionic lipids cardiolipin and phosphatidylglycerol, indicating their close proximity to the channel in biological membranes and supporting their functional relevance. Finally, we demonstrate that KcsA can be reconstituted into planar lipid bilayers directly from native nanodiscs, which enables functional characterization of the channel by electrophysiology without first depriving the protein of its native environment. Together, these findings highlight the potential of the use of native nanodiscs as a tool in the study of ion channels, and of membrane proteins in general. PMID:25512535

  20. Channel Temperature Estimates for Microwave AlGaN/GaN Power HEMTS on SiC and Sapphire

    NASA Technical Reports Server (NTRS)

    Freeman, Jon C.

    2003-01-01

    A simple technique to estimate the channel temperature of a generic AlGaN/GaN HEMTs on SiC or Sapphire, while incorporating temperature dependence of the thermal conductivity is presented. The procedure is validated b y comparing it's predictions with the experimentally measured temperatures in devices presented in three recently published articles.

  1. A small-area low-power current readout circuit using two-stage conversion method for 64-channel CNT sensor arrays.

    PubMed

    Shin, Young-San; Lee, Seongsoo; Wee, Jae-Kyung; Song, Inchae

    2013-06-01

    In this paper, a small-area and low-power current readout circuit with a novel two-stage conversion method is presented for 64-channel CNT (carbon nanotube) sensor arrays. In the first stage, current of each CNT sensor is amplified by 64 active input current mirrors (AICMs). In the second stage, the amplified current is converted to a voltage level through the shared variable gain amplifier (S-VGA). Then the S-VGA output is digitalized by successive approximation register analog-to-digital converter (SAR-ADC). The proposed readout circuit significantly reduces chip area and power consumption, since VGA is shared over 64 channels and passive elements are used only in S-VGA. Fabricated chip area is 0.173 mm(2) in 0.13 μm CMOS technology. Measured power consumption and linearity error are 73.06 μW and 5.3%, respectively, at the input current range of 10 nA-10 μA and conversion rate of 640 samples/s. A prototype real-time CNT sensor system was implemented using the fabricated readout circuit, and successfully detected alcohol reaction.

  2. A small-area low-power current readout circuit using two-stage conversion method for 64-channel CNT sensor arrays.

    PubMed

    Shin, Young-San; Lee, Seongsoo; Wee, Jae-Kyung; Song, Inchae

    2013-06-01

    In this paper, a small-area and low-power current readout circuit with a novel two-stage conversion method is presented for 64-channel CNT (carbon nanotube) sensor arrays. In the first stage, current of each CNT sensor is amplified by 64 active input current mirrors (AICMs). In the second stage, the amplified current is converted to a voltage level through the shared variable gain amplifier (S-VGA). Then the S-VGA output is digitalized by successive approximation register analog-to-digital converter (SAR-ADC). The proposed readout circuit significantly reduces chip area and power consumption, since VGA is shared over 64 channels and passive elements are used only in S-VGA. Fabricated chip area is 0.173 mm(2) in 0.13 μm CMOS technology. Measured power consumption and linearity error are 73.06 μW and 5.3%, respectively, at the input current range of 10 nA-10 μA and conversion rate of 640 samples/s. A prototype real-time CNT sensor system was implemented using the fabricated readout circuit, and successfully detected alcohol reaction. PMID:23853327

  3. An 8 channel, 20 V output CMOS switching driver with 3.3 V power supply using triple-well biasing techniques for integrated MEMS device control

    NASA Astrophysics Data System (ADS)

    Takayasu, Motohiro; Shirane, Atsushi; Lee, Sangyeop; Yamane, Daisuke; Ito, Hiroyuki; Mi, Xiaoyu; Inoue, Hiroaki; Nakazawa, Fumihiko; Ueda, Satoshi; Ishihara, Noboru; Masu, Kazuya

    2014-01-01

    An 8 channel output switching driver has been implemented for integrated micro-electro-mechanical systems (MEMS) device control using the 0.18 µm CMOS process technology. The driver can output 20 V switching signals for 1 nF capacitive loads with a 3.3 V power supply. The switching time is less than 100 µs. To obtain a high output voltage that exceeds the transistors’ and capacitors’ breakdown voltages, a new charge pump and a discharge circuit, using optimal transistor-well-biasing techniques for triple-well-structured n-MOS transistors, were investigated, and the circuit parameters were also optimized to obtain high-speed switching.

  4. 38. VIEW OF COTTRELL MAGNETIC IMPULSE GENERATOR ADJACENT TO SIX ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    38. VIEW OF COTTRELL MAGNETIC IMPULSE GENERATOR ADJACENT TO SIX GAP ROTARY RECTIFIER. THIS UNIT GENERATED A MAGNETIC PULSE WHICH WAS TRANSMITTED TO THE COLLECTION PLATES IN THE ELECTROSTATIC PRECIPITATOR CHAMBER. THESE PERIODIC PULSES VIBRATE THE PLATES AND CAUSE PRECIPITATED ARTICLES OF SMOKE AND FLY ASH TO FALL TO THE BOTTOM OF THE PRECIPITATOR CHAMBER. - New York, New Haven & Hartford Railroad, Cos Cob Power Plant, Sound Shore Drive, Greenwich, Fairfield County, CT

  5. Comparative study of forced convection of a power-law fluid in a channel with a built-in square cylinder

    NASA Astrophysics Data System (ADS)

    Mohebbi, R.; Nazari, M.; Kayhani, M. H.

    2016-01-01

    A detailed comparison between the lattice Boltzmann method and the finite element method is presented for an incompressible steady laminar flow and heat transfer of a power-law fluid past a square cylinder between two parallel plates. Computations are performed for three different blockage ratios (ratios of the square side length to the channel width) and different values of the power-law index n covering both pseudo-plastic fluids ( n < 1) and dilatant fluids ( n > 1). The methodology is validated against the exact solution. The local and averaged Nusselt numbers are also presented. The results show that the relatively simple lattice Boltzmann method is a good alternative to the finite element method for analyzing non-Newtonian fluids.

  6. Co-integration of nano-scale vertical- and horizontal-channel metal-oxide-semiconductor field-effect transistors for low power CMOS technology.

    PubMed

    Sun, Min-Chul; Kim, Garam; Kim, Sang Wan; Kim, Hyun Woo; Kim, Hyungjin; Lee, Jong-Ho; Shin, Hyungcheol; Park, Byung-Gook

    2012-07-01

    In order to extend the conventional low power Si CMOS technology beyond the 20-nm node without SOI substrates, we propose a novel co-integration scheme to build horizontal- and vertical-channel MOSFETs together and verify the idea using TCAD simulations. From the fabrication viewpoint, it is highlighted that this scheme provides additional vertical devices with good scalability by adding a few steps to the conventional CMOS process flow for fin formation. In addition, the benefits of the co-integrated vertical devices are investigated using a TCAD device simulation. From this study, it is confirmed that the vertical device shows improved off-current control and a larger drive current when the body dimension is less than 20 nm, due to the electric field coupling effect at the double-gated channel. Finally, the benefits from the circuit design viewpoint, such as the larger midpoint gain and beta and lower power consumption, are confirmed by the mixed-mode circuit simulation study.

  7. Low-power bacteriorhodopsin-silicon n-channel metal-oxide field-effect transistor photoreceiver.

    PubMed

    Shin, Jonghyun; Bhattacharya, Pallab; Yuan, Hao-Chih; Ma, Zhenqiang; Váró, György

    2007-03-01

    A bacteriorhodopsin (bR)-silicon n-channel metal-oxide field-effect transistor (NMOSFET) monolithically integrated photoreceiver is demonstrated. The bR film is selectively formed on an external gate electrode of the transistor by electrophoretic deposition. A modified biasing circuit is incorporated, which helps to match the resistance of the bR film to the input impedance of the NMOSFET and to shift the operating point of the transistor to coincide with the maximum gain. The photoreceiver exhibits a responsivity of 4.7 mA/W. PMID:17392901

  8. Nonlinear channelizer.

    PubMed

    In, Visarath; Longhini, Patrick; Kho, Andy; Neff, Joseph D; Leung, Daniel; Liu, Norman; Meadows, Brian K; Gordon, Frank; Bulsara, Adi R; Palacios, Antonio

    2012-12-01

    The nonlinear channelizer is an integrated circuit made up of large parallel arrays of analog nonlinear oscillators, which, collectively, serve as a broad-spectrum analyzer with the ability to receive complex signals containing multiple frequencies and instantaneously lock-on or respond to a received signal in a few oscillation cycles. The concept is based on the generation of internal oscillations in coupled nonlinear systems that do not normally oscillate in the absence of coupling. In particular, the system consists of unidirectionally coupled bistable nonlinear elements, where the frequency and other dynamical characteristics of the emergent oscillations depend on the system's internal parameters and the received signal. These properties and characteristics are being employed to develop a system capable of locking onto any arbitrary input radio frequency signal. The system is efficient by eliminating the need for high-speed, high-accuracy analog-to-digital converters, and compact by making use of nonlinear coupled systems to act as a channelizer (frequency binning and channeling), a low noise amplifier, and a frequency down-converter in a single step which, in turn, will reduce the size, weight, power, and cost of the entire communication system. This paper covers the theory, numerical simulations, and some engineering details that validate the concept at the frequency band of 1-4 GHz.

  9. Performance of Reverse-Link Synchronous DS-CDMA System on a Frequency-Selective Multipath Fading Channel with Imperfect Power Control

    NASA Astrophysics Data System (ADS)

    Hwang, Seung-Hoon; Kim, Duk Kyung

    2002-12-01

    We analyze the performance for reverse-link synchronous DS-CDMA system in a frequency-selective Rayleigh fading channel with an imperfect power control scheme. The performance degradation due to power control error (PCE), which is approximated by a log-normally distributed random variable, is estimated as a function of the standard deviation of the PCE. In addition, we investigate the impacts of the multipath intensity profile (MIP) shape and the number of resolvable paths on the performance. Finally, the coded bit error performance is evaluated in order to estimate the system capacity. Comparing with the conventional CDMA system, we show an achievable gain of from 59% to 23% for reverse-link synchronous transmission technique (RLSTT) in the presence of imperfect power control over asynchronous transmission for[InlineEquation not available: see fulltext.]. As well, the effect of tradeoff between orthogonality and diversity can be seen according to the number of multipaths, and the tendency is kept even in the presence of PCE. We conclude that the capacity can be further improved via the RLSTT, because the DS-CDMA system is very sensitive to power control imperfections.

  10. Development, assembly, and validation of an SMA-actuated two-joint nozzle and six-channel power supply for use in a smart inhaler system

    NASA Astrophysics Data System (ADS)

    Furst, Stephen J.; Hangekar, Rohan; Seelecke, Stefan

    2010-04-01

    The Smart Inhaler design concept recently developed at NC State University has the potential to target the delivery of inhaled aerosol medication to specified locations within the lung system. This targeted delivery could help patients with pulmonary ailments by reducing the exposure of healthy lung tissue to potentially harmful medications. However, controlled delivery can only be accomplished if medication is injected at a precise location in an inhaled stream of properly conditioned laminar flow. In particular, the medication must be injected into the inhaled flow using a small nozzle that can be positioned without disturbing the flow. This paper outlines the procedure used to assemble and control a key component of the smart inhaler: a shape memory alloy (SMA) based dual-joint flexible nozzle that exploits the sensing and actuating capabilities of thermally activated SMA wires. A novel 6-channel power-supply is used to control input power and measure the resistance across the SMA. Since a practical fabrication process may result in SMA wires with different contact resistances, the power supply employs an initialization procedure to self-calibrate and provide normalized power distribution 6 SMA wires simultaneously. Furthermore, a robust control scheme is used to ensure that a constant current is provided to the wires. In validation tests, a LabVIEW-based video positioning system was used to measure the deflection of the nozzle tip and joint rotation. Results show that the carefully controlled assembly of a stream-lined nozzle can produce a practical smart structure, and joint rotation is predictable and repeatable when power input is also controlled. Future work will assess the use of the SMA-resistance measurement as position feedback and PID position control power as a measurement of the convective cooling that results from the moving airflow.

  11. Surface morphology and surface energy of anode materials influence power outputs in a multi-channel mediatorless bio-photovoltaic (BPV) system.

    PubMed

    Bombelli, Paolo; Zarrouati, Marie; Thorne, Rebecca J; Schneider, Kenneth; Rowden, Stephen J L; Ali, Akin; Yunus, Kamran; Cameron, Petra J; Fisher, Adrian C; Ian Wilson, D; Howe, Christopher J; McCormick, Alistair J

    2012-09-21

    Bio-photovoltaic cells (BPVs) are a new photo-bio-electrochemical technology for harnessing solar energy using the photosynthetic activity of autotrophic organisms. Currently power outputs from BPVs are generally low and suffer from low efficiencies. However, a better understanding of the electrochemical interactions between the microbes and conductive materials will be likely to lead to increased power yields. In the current study, the fresh-water, filamentous cyanobacterium Pseudanabaena limnetica (also known as Oscillatoria limnetica) was investigated for exoelectrogenic activity. Biofilms of P. limnetica showed a significant photo response during light-dark cycling in BPVs under mediatorless conditions. A multi-channel BPV device was developed to compare quantitatively the performance of photosynthetic biofilms of this species using a variety of different anodic conductive materials: indium tin oxide-coated polyethylene terephthalate (ITO), stainless steel (SS), glass coated with a conductive polymer (PANI), and carbon paper (CP). Although biofilm growth rates were generally comparable on all materials tested, the amplitude of the photo response and achievable maximum power outputs were significantly different. ITO and SS demonstrated the largest photo responses, whereas CP showed the lowest power outputs under both light and dark conditions. Furthermore, differences in the ratios of light : dark power outputs indicated that the electrochemical interactions between photosynthetic microbes and the anode may differ under light and dark conditions depending on the anodic material used. Comparisons between BPV performances and material characteristics revealed that surface roughness and surface energy, particularly the ratio of non-polar to polar interactions (the CQ ratio), may be more important than available surface area in determining biocompatibility and maximum power outputs in microbial electrochemical systems. Notably, CP was readily outperformed by all

  12. Raman Channel Temperature Measurement of SiC MESFET as a Function of Ambient Temperature and DC Power

    NASA Technical Reports Server (NTRS)

    Ponchak, George E.; Eldridge, Jeffrey J.; Krainsky, Isay L.

    2009-01-01

    Raman spectroscopy is used to measure the junction temperature of a Cree SiC MESFET as a function of the ambient temperature and DC power. The carrier temperature, which is approximately equal to the ambient temperature, is varied from 25 C to 450 C, and the transistor is biased with VDS=10V and IDS of 50 mA and 100 mA. It is shown that the junction temperature is approximately 52 and 100 C higher than the ambient temperature for the DC power of 500 and 1000 mW, respectively.

  13. Variable length adjacent partitioning for PTS based PAPR reduction of OFDM signal

    SciTech Connect

    Ibraheem, Zeyid T.; Rahman, Md. Mijanur; Yaakob, S. N.; Razalli, Mohammad Shahrazel; Kadhim, Rasim A.

    2015-05-15

    Peak-to-Average power ratio (PAPR) is a major drawback in OFDM communication. It leads the power amplifier into nonlinear region operation resulting into loss of data integrity. As such, there is a strong motivation to find techniques to reduce PAPR. Partial Transmit Sequence (PTS) is an attractive scheme for this purpose. Judicious partitioning the OFDM data frame into disjoint subsets is a pivotal component of any PTS scheme. Out of the existing partitioning techniques, adjacent partitioning is characterized by an attractive trade-off between cost and performance. With an aim of determining effects of length variability of adjacent partitions, we performed an investigation into the performances of a variable length adjacent partitioning (VL-AP) and fixed length adjacent partitioning in comparison with other partitioning schemes such as pseudorandom partitioning. Simulation results with different modulation and partitioning scenarios showed that fixed length adjacent partition had better performance compared to variable length adjacent partitioning. As expected, simulation results showed a slightly better performance of pseudorandom partitioning technique compared to fixed and variable adjacent partitioning schemes. However, as the pseudorandom technique incurs high computational complexities, adjacent partitioning schemes were still seen as favorable candidates for PAPR reduction.

  14. On the time-course of adjacent and non-adjacent transposed-letter priming

    PubMed Central

    Ktori, Maria; Kingma, Brechtsje; Hannagan, Thomas; Holcomb, Phillip J.; Grainger, Jonathan

    2014-01-01

    We compared effects of adjacent (e.g., atricle-ARTICLE) and non-adjacent (e.g., actirle-ARTICLE) transposed-letter (TL) primes in an ERP study using the sandwich priming technique. TL priming was measured relative to the standard double-substitution condition. We found significantly stronger priming effects for adjacent transpositions than non-adjacent transpositions (with 2 intervening letters) in behavioral responses (lexical decision latencies), and the adjacent priming effects emerged earlier in the ERP signal, at around 200 ms post-target onset. Non-adjacent priming effects emerged about 50 ms later and were short-lived, being significant only in the 250-300 ms time-window. Adjacent transpositions on the other hand continued to produce priming in the N400 time-window (300-500 ms post-target onset). This qualitatively different pattern of priming effects for adjacent and non-adjacent transpositions is discussed in the light of different accounts of letter transposition effects, and the utility of drawing a distinction between positional flexibility and positional noise. PMID:25364497

  15. An engineered dimeric protein pore that spans adjacent lipid bilayers

    PubMed Central

    Mantri, Shiksha; Sapra, K. Tanuj; Cheley, Stephen; Sharp, Thomas H.; Bayley, Hagan

    2013-01-01

    The bottom-up construction of artificial tissues is an underexplored area of synthetic biology. An important challenge is communication between constituent compartments of the engineered tissue and between the engineered tissue and additional compartments, including extracellular fluids, further engineered tissue and living cells. Here we present a dimeric transmembrane pore that can span two adjacent lipid bilayers and thereby allow aqueous compartments to communicate. Two heptameric staphylococcal α-hemolysin (αHL) pores were covalently linked in an aligned cap-to-cap orientation. The structure of the dimer, (α7)2, was confirmed by biochemical analysis, transmission electron microscopy (TEM) and single-channel electrical recording. We show that one of two β barrels of (α7)2 can insert into the lipid bilayer of a small unilamellar vesicle, while the other spans a planar lipid bilayer. (α7)2 pores spanning two bilayers were also observed by TEM. PMID:23591892

  16. Scalable high-power (>1kW/cm^2) diode laser stacks based on silicon monolithic micro-channel coolers

    NASA Astrophysics Data System (ADS)

    Reichert, Patrick; Fouksman, Michael; Zhou, Hailong; Nabors, David; Alcala, Jiro; Tolman, Sherry; Toivonen, Mika; Lehkonen, Sami; Haapamaa, Jouko

    2007-02-01

    We describe the performance and reliability of high power vertical diode stacks based on silicon monolithic microchannel coolers (SiMMs) operating at >1000W/cm2 CW at 808 and 940nm. The monolithic nature of these stacks makes them inherently robust and compact. Typical emitting dimensions for a 10-bar stack are ~8.8mm × 10mm with CW output power up to 1.5kW. Originally developed at Lawrence Livermore National Laboratory and now actively being developed for commercial applications at Coherent, this technology offers several advantages over current copper-based micro-channel coolers. These devices do not require use of DI water, strict monitoring and control of the pH level, careful control of the water velocity, or sealed cooling systems. The need for hydrostatic seals is also drastically reduced. A typical ten bar stack requires only 2 o-ring seals, compared to 20 such seals for a similar stack using copper microchannel cooling. Mature and readily available wet etching technology allows for cost effective batch fabrication of the sub-mount structure while achieving repeatable high precision components based on photolithographic fabrication processes.

  17. MINARETS WILDERNESS AND ADJACENT AREAS, CALIFORNIA.

    USGS Publications Warehouse

    Huber, N. King; Thurber, Horace K.

    1984-01-01

    A mineral survey of the Minarets Wilderness and adjacent areas in the central Sierra Nevada, California was conducted. The results of the survey indicate that the study area has a substantiated resource potential for small deposits of copper, silver, zinc, lead, and iron, and a probable mineral-resource potential for molybdenum. No energy-resource potential was identified in the study.

  18. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES CARRIAGE OF BULK SOLID MATERIALS... transporting a material that Table 148.10 of this part associates with a reference to this section, the following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  19. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES CARRIAGE OF BULK SOLID MATERIALS... transporting a material that Table 148.10 of this part associates with a reference to this section, the following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  20. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES CARRIAGE OF BULK SOLID MATERIALS... transporting a material that Table 148.10 of this part associates with a reference to this section, the following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  1. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES CARRIAGE OF BULK SOLID MATERIALS... transporting a material that Table 148.10 of this part associates with a reference to this section, the following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  2. A Unified Distortion Analysis of Nonlinear Power Amplifiers with Memory Effects for OFDM Signals

    NASA Astrophysics Data System (ADS)

    Zhang, Yitao; Araki, Kiyomichi

    Nonlinear distortions in power amplifiers (PAs) generate spectral regrowth at the output, which causes interference to adjacent channels and errors in digitally modulated signals. This paper presents a novel method to evaluate adjacent channel leakage power ratio (ACPR) and error vector magnitude (EVM) from the amplitude-to-amplitude (AM/AM) and amplitude-to-phase (AM/PM) characteristics. The transmitted signal is considered to be complex Gaussian distributed in orthogonal frequency-division multiplexing (OFDM) systems. We use the Mehler formula to derive closed-form expressions of the PAs output power spectral density (PSD), ACPR and EVM for memoryless PA and memory PA respectively. We inspect the derived relationships using an OFDM signal in the IEEE 802.11a WLAN standard. Simulation results show that the proposed method is appropriate to predict the ACPR and EVM values of the nonlinear PA output in OFDM systems, when the AM/AM and AM/PM characteristics are known.

  3. Optimal channels for channelized quadratic estimators.

    PubMed

    Kupinski, Meredith K; Clarkson, Eric

    2016-06-01

    We present a new method for computing optimized channels for estimation tasks that is feasible for high-dimensional image data. Maximum-likelihood (ML) parameter estimates are challenging to compute from high-dimensional likelihoods. The dimensionality reduction from M measurements to L channels is a critical advantage of channelized quadratic estimators (CQEs), since estimating likelihood moments from channelized data requires smaller sample sizes and inverting a smaller covariance matrix is easier. The channelized likelihood is then used to form ML estimates of the parameter(s). In this work we choose an imaging example in which the second-order statistics of the image data depend upon the parameter of interest: the correlation length. Correlation lengths are used to approximate background textures in many imaging applications, and in these cases an estimate of the correlation length is useful for pre-whitening. In a simulation study we compare the estimation performance, as measured by the root-mean-squared error (RMSE), of correlation length estimates from CQE and power spectral density (PSD) distribution fitting. To abide by the assumptions of the PSD method we simulate an ergodic, isotropic, stationary, and zero-mean random process. These assumptions are not part of the CQE formalism. The CQE method assumes a Gaussian channelized likelihood that can be a valid for non-Gaussian image data, since the channel outputs are formed from weighted sums of the image elements. We have shown that, for three or more channels, the RMSE of CQE estimates of correlation length is lower than conventional PSD estimates. We also show that computing CQE by using a standard nonlinear optimization method produces channels that yield RMSE within 2% of the analytic optimum. CQE estimates of anisotropic correlation length estimation are reported to demonstrate this technique on a two-parameter estimation problem. PMID:27409452

  4. Historical volcanoes of Armenia and adjacent areas: What is revisited?

    NASA Astrophysics Data System (ADS)

    Karakhanian, A.; Jrbashyan, R.; Trifonov, V.; Philip, H.; Arakelian, S.; Avagyan, A.; Baghdassaryan, H.; Davtian, V.

    2006-07-01

    The validity of some data in Karakhanian et al. [Karakhanian, A., Djrbashian, R., Trifonov V., Philip H., Arakelian S., Avagian, A., 2002. Holocene-historical volcanism and active faults as natural risk factor for Armenia and adjacent countries. Journal of Volcanology and Geothermal Research, 113, 1, 319-344; Karakhanian, A., Jrbashyan, R., Trifonov, V., Philip, H., Arakelian, S., Avagyan, A., Baghdassaryan, H., Davtian, V., Ghoukassyan, Yu., 2003. Volcanic hazards in the region of the Armenian nuclear power plant. Journal of Volcanology and Geothermal Research, 126/1-2, 31-62] that are revisited by R. Haroutiunian is considered. A conclusion is made that the revisions suggested by Haroutiunian concern unessential parts of the content of work by Karakhanian et al. [Karakhanian, A., Djrbashian, R., Trifonov V., Philip H., Arakelian S., Avagian, A., 2002. Holocene-historical volcanism and active faults as natural risk factor for Armenia and adjacent countries. Journal of Volcanology and Geothermal Research, 113, 1, 319-344; Karakhanian, A., Jrbashyan, R., Trifonov, V., Philip, H., Arakelian, S., Avagyan, A., Baghdassaryan, H., Davtian, V., Ghoukassyan, Yu., 2003. Volcanic hazards in the region of the Armenian nuclear power plant. Journal of Volcanology and Geothermal Research, 126/1-2, 31-62]. This article presents new evidence and re-proves the earlier conclusions that are disputed or revised by R. Haroutiunian.

  5. Adjacent Segment Pathology after Lumbar Spinal Fusion.

    PubMed

    Lee, Jae Chul; Choi, Sung-Woo

    2015-10-01

    One of the major clinical issues encountered after lumbar spinal fusion is the development of adjacent segment pathology (ASP) caused by increased mechanical stress at adjacent segments, and resulting in various radiographic changes and clinical symptoms. This condition may require surgical intervention. The incidence of ASP varies with both the definition and methodology adopted in individual studies; various risk factors for this condition have been identified, although a significant controversy still exists regarding their significance. Motion-preserving devices have been developed, and some studies have shown their efficacy of preventing ASP. Surgeons should be aware of the risk factors of ASP when planning a surgery, and accordingly counsel their patients preoperatively. PMID:26435804

  6. Adjacent Segment Pathology after Lumbar Spinal Fusion

    PubMed Central

    Lee, Jae Chul

    2015-01-01

    One of the major clinical issues encountered after lumbar spinal fusion is the development of adjacent segment pathology (ASP) caused by increased mechanical stress at adjacent segments, and resulting in various radiographic changes and clinical symptoms. This condition may require surgical intervention. The incidence of ASP varies with both the definition and methodology adopted in individual studies; various risk factors for this condition have been identified, although a significant controversy still exists regarding their significance. Motion-preserving devices have been developed, and some studies have shown their efficacy of preventing ASP. Surgeons should be aware of the risk factors of ASP when planning a surgery, and accordingly counsel their patients preoperatively. PMID:26435804

  7. Adjacent Segment Pathology after Anterior Cervical Fusion.

    PubMed

    Chung, Jae Yoon; Park, Jong-Beom; Seo, Hyoung-Yeon; Kim, Sung Kyu

    2016-06-01

    Anterior cervical fusion has become a standard of care for numerous pathologic conditions of the cervical spine. However, subsequent development of clinically significant disc disease at levels adjacent to fused discs is a serious long-term complication of this procedure. As more patients live longer after surgery, it is foreseeable that adjacent segment pathology (ASP) will develop in increasing numbers of patients. Also, ASP has been studied more intensively with the recent popularity of motion preservation technologies like total disc arthroplasty. The true nature and scope of ASP remains poorly understood. The etiology of ASP is most likely multifactorial. Various factors including altered biomechanical stresses, surgical disruption of soft tissue and the natural history of cervical disc disease contribute to the development of ASP. General factors associated with disc degeneration including gender, age, smoking and sports may play a role in the development of ASP. Postoperative sagittal alignment and type of surgery are also considered potential causes of ASP. Therefore, a spine surgeon must be particularly careful to avoid unnecessary disruption of the musculoligamentous structures, reduced risk of direct injury to the disc during dissection and maintain a safe margin between the plate edge and adjacent vertebrae during anterior cervical fusion.

  8. Adjacent Segment Pathology after Anterior Cervical Fusion

    PubMed Central

    Chung, Jae Yoon; Park, Jong-Beom; Seo, Hyoung-Yeon

    2016-01-01

    Anterior cervical fusion has become a standard of care for numerous pathologic conditions of the cervical spine. However, subsequent development of clinically significant disc disease at levels adjacent to fused discs is a serious long-term complication of this procedure. As more patients live longer after surgery, it is foreseeable that adjacent segment pathology (ASP) will develop in increasing numbers of patients. Also, ASP has been studied more intensively with the recent popularity of motion preservation technologies like total disc arthroplasty. The true nature and scope of ASP remains poorly understood. The etiology of ASP is most likely multifactorial. Various factors including altered biomechanical stresses, surgical disruption of soft tissue and the natural history of cervical disc disease contribute to the development of ASP. General factors associated with disc degeneration including gender, age, smoking and sports may play a role in the development of ASP. Postoperative sagittal alignment and type of surgery are also considered potential causes of ASP. Therefore, a spine surgeon must be particularly careful to avoid unnecessary disruption of the musculoligamentous structures, reduced risk of direct injury to the disc during dissection and maintain a safe margin between the plate edge and adjacent vertebrae during anterior cervical fusion. PMID:27340541

  9. Fractional channel multichannel analyzer

    DOEpatents

    Brackenbush, Larry W.; Anderson, Gordon A.

    1994-01-01

    A multichannel analyzer incorporating the features of the present invention obtains the effect of fractional channels thus greatly reducing the number of actual channels necessary to record complex line spectra. This is accomplished by using an analog-to-digital converter in the asynscronous mode, i.e., the gate pulse from the pulse height-to-pulse width converter is not synchronized with the signal from a clock oscillator. This saves power and reduces the number of components required on the board to achieve the effect of radically expanding the number of channels without changing the circuit board.

  10. Transport and deposition of river sediment in the Changjiang estuary and adjacent continental shelf

    USGS Publications Warehouse

    Milliman, John D.; Huang-ting, S.; Zuo-sheng, Y.; Mead, R.H.

    1985-01-01

    Hydrographic observations, suspended-sediment measurements, and historical data indicate transport paths and sinks for sediment within the Changjiang estuary and adjacent shelf. Most of the sediment transported by the Changjiang to the ocean is carried through the North Channel of the South Branch. Sediment transport is directly related to river stage, but tidal phase (spring vs neap tides) also plays an important role. An estimated 40% of the sediment load in the river is deposited in the estuary, mostly in and seaward of the South Channel. The remaining sediment is deposited directly offshore during flood seasons, but much is resuspended and carried southward by subsequent winter storms. ?? 1985.

  11. A Hot Knife Through Ice-Cream: Earthflow Response to Channel Incision (Or Channel Response to Earthflows?), Eel River Canyon, California

    NASA Astrophysics Data System (ADS)

    Mackey, B. H.; Roering, J. J.; McKean, J. A.

    2007-12-01

    Abundant glacier-like earthflow features are recognized as a primary erosional process in the highly erodable Franciscan Melange of the Eel River Basin, CA. Despite their prominence in this "melting ice-cream" topography, many questions regarding their effects on the long term sediment flux from this rapidly eroding basin remain unresolved. For example, does an earthflow's basal shear zone propagate vertically downwards with vertical river incision? What controls the upslope and lateral extent of individual earthflows? How does the erosive power of a river influence the rate of earthflow movement, or conversely do earthflow toe deposits regulate the rate of river incision? Here we present preliminary findings derived from study of 200km2 of lidar data (1m resolution) covering hillslopes adjacent to 30km of the Eel River. Lidar allows detailed analysis of the interaction between earthflows and the drainage network, and we document how inferred changes in local base level are propagated throughout adjacent hillslopes via earthflow movement. The most active earthflows (determined by field surveying and analysis of aerial photos rectified using lidar- generated digital topography) coincide with locally steep sections of channel, while downstream of the most active flows we frequently observe less-active or dormant earthflows. This observation supports the idea that the locations of the most active earthflows coincide with headward propagating knickpoints in the channel. The rate of earthflow movement appears to slow when an earthflow exhausts the upslope area of easily mobilized sediment. Earthflow toes can protrude directly into the channel, causing the channel to narrow and steepen, and even undercut the opposite bank. Large resistant boulders (>2m diameter) transported by the earthflow accumulate in the streambed and appear to both act as a check on further channel incision and earthflow movement. In contrast, areas adjacent to active earthflows exhibit smooth

  12. Interdigitated photovoltaic power conversion device

    DOEpatents

    Ward, James Scott; Wanlass, Mark Woodbury; Gessert, Timothy Arthur

    1999-01-01

    A photovoltaic power conversion device has a top surface adapted to receive impinging radiation. The device includes at least two adjacent, serially connected cells. Each cell includes a semi-insulating substrate and a lateral conductivity layer of a first doped electrical conductivity disposed on the substrate. A base layer is disposed on the lateral conductivity layer and has the same electrical charge conductivity thereof. An emitter layer of a second doped electrical conductivity of opposite electrical charge is disposed on the base layer and forms a p-n junction therebetween. A plurality of spaced channels are formed in the emitter and base layers to expose the lateral conductivity layer at the bottoms thereof. A front contact grid is positioned on the top surface of the emitter layer of each cell. A first current collector is positioned along one outside edge of at least one first cell. A back contact grid is positioned in the channels at the top surface of the device for engagement with the lateral conductivity layer. A second current collector is positioned along at least one outside edge of at least one oppositely disposed second cell. Finally, an interdigitation mechanism is provided for serially connecting the front contact grid of one cell to the back contact grid of an adjacent cell at the top surface of the device.

  13. Interdigitated photovoltaic power conversion device

    DOEpatents

    Ward, J.S.; Wanlass, M.W.; Gessert, T.A.

    1999-04-27

    A photovoltaic power conversion device has a top surface adapted to receive impinging radiation. The device includes at least two adjacent, serially connected cells. Each cell includes a semi-insulating substrate and a lateral conductivity layer of a first doped electrical conductivity disposed on the substrate. A base layer is disposed on the lateral conductivity layer and has the same electrical charge conductivity thereof. An emitter layer of a second doped electrical conductivity of opposite electrical charge is disposed on the base layer and forms a p-n junction therebetween. A plurality of spaced channels are formed in the emitter and base layers to expose the lateral conductivity layer at the bottoms thereof. A front contact grid is positioned on the top surface of the emitter layer of each cell. A first current collector is positioned along one outside edge of at least one first cell. A back contact grid is positioned in the channels at the top surface of the device for engagement with the lateral conductivity layer. A second current collector is positioned along at least one outside edge of at least one oppositely disposed second cell. Finally, an interdigitation mechanism is provided for serially connecting the front contact grid of one cell to the back contact grid of an adjacent cell at the top surface of the device. 15 figs.

  14. Exchange coupling between laterally adjacent nanomagnets

    NASA Astrophysics Data System (ADS)

    Dey, H.; Csaba, G.; Bernstein, G. H.; Porod, W.

    2016-09-01

    We experimentally demonstrate exchange-coupling between laterally adjacent nanomagnets. Our results show that two neighboring nanomagnets that are each antiferromagnetically exchange-coupled to a common ferromagnetic bottom layer can be brought into strong ferromagnetic interaction. Simulations show that interlayer exchange coupling effectively promotes ferromagnetic alignment between the two nanomagnets, as opposed to antiferromagnetic alignment due to dipole-coupling. In order to experimentally demonstrate the proposed scheme, we fabricated arrays of pairs of elongated, single-domain nanomagnets. Magnetic force microscopy measurements show that most of the pairs are ferromagnetically ordered. The results are in agreement with micromagnetic simulations. The presented scheme can achieve coupling strengths that are significantly stronger than dipole coupling, potentially enabling far-reaching applications in Nanomagnet Logic, spin-wave devices and three-dimensional storage and computing.

  15. Boundary Layers of Air Adjacent to Cylinders

    PubMed Central

    Nobel, Park S.

    1974-01-01

    Using existing heat transfer data, a relatively simple expression was developed for estimating the effective thickness of the boundary layer of air surrounding cylinders. For wind velocities from 10 to 1000 cm/second, the calculated boundary-layer thickness agreed with that determined for water vapor diffusion from a moistened cylindrical surface 2 cm in diameter. It correctly predicted the resistance for water vapor movement across the boundary layers adjacent to the (cylindrical) inflorescence stems of Xanthorrhoea australis R. Br. and Scirpus validus Vahl and the leaves of Allium cepa L. The boundary-layer thickness decreased as the turbulence intensity increased. For a turbulence intensity representative of field conditions (0.5) and for νwindd between 200 and 30,000 cm2/second (where νwind is the mean wind velocity and d is the cylinder diameter), the effective boundary-layer thickness in centimeters was equal to [Formula: see text]. PMID:16658855

  16. TRP Channels

    NASA Astrophysics Data System (ADS)

    Voets, Thomas; Owsianik, Grzegorz; Nilius, Bernd

    The TRP superfamily represents a highly diverse group of cation-permeable ion channels related to the product of the Drosophila trp (transient receptor potential) gene. The cloning and characterization of members of this cation channel family has experienced a remarkable growth during the last decade, uncovering a wealth of information concerning the role of TRP channels in a variety of cell types, tissues, and species. Initially, TRP channels were mainly considered as phospholipase C (PLC)-dependent and/or store-operated Ca2+-permeable cation channels. More recent research has highlighted the sensitivity of TRP channels to a broad array of chemical and physical stimuli, allowing them to function as dedicated biological sensors involved in processes ranging from vision to taste, tactile sensation, and hearing. Moreover, the tailored selectivity of certain TRP channels enables them to play key roles in the cellular uptake and/or transepithelial transport of Ca2+, Mg2+, and trace metal ions. In this chapter we give a brief overview of the TRP channel superfamily followed by a survey of current knowledge concerning their structure and activation mechanisms.

  17. 47 CFR 74.702 - Channel assignments.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.702 Channel assignments. (a) An applicant for a new low power TV or TV translator... standard VHF Channels (2 to 13 inclusive) may be assigned to a VHF low power TV or TV translator...

  18. 47 CFR 74.702 - Channel assignments.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.702 Channel assignments. (a) An applicant for a new low power TV or TV translator... standard VHF Channels (2 to 13 inclusive) may be assigned to a VHF low power TV or TV translator...

  19. 47 CFR 74.702 - Channel assignments.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.702 Channel assignments. (a) An applicant for a new low power TV or TV translator... standard VHF Channels (2 to 13 inclusive) may be assigned to a VHF low power TV or TV translator...

  20. 47 CFR 74.702 - Channel assignments.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.702 Channel assignments. (a) An applicant for a new low power TV or TV translator... standard VHF Channels (2 to 13 inclusive) may be assigned to a VHF low power TV or TV translator...

  1. 47 CFR 74.702 - Channel assignments.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.702 Channel assignments. (a) An applicant for a new low power TV or TV translator... standard VHF Channels (2 to 13 inclusive) may be assigned to a VHF low power TV or TV translator...

  2. 33 CFR 80.1395 - Puget Sound and adjacent waters.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Puget Sound and adjacent waters... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Thirteenth District § 80.1395 Puget Sound and adjacent waters. The 72 COLREGS shall apply on all waters of Puget Sound and adjacent waters, including Lake...

  3. 33 CFR 80.1395 - Puget Sound and adjacent waters.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Puget Sound and adjacent waters... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Thirteenth District § 80.1395 Puget Sound and adjacent waters. The 72 COLREGS shall apply on all waters of Puget Sound and adjacent waters, including Lake...

  4. 33 CFR 80.1395 - Puget Sound and adjacent waters.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Puget Sound and adjacent waters... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Thirteenth District § 80.1395 Puget Sound and adjacent waters. The 72 COLREGS shall apply on all waters of Puget Sound and adjacent waters, including Lake...

  5. 33 CFR 80.1395 - Puget Sound and adjacent waters.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Puget Sound and adjacent waters... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Thirteenth District § 80.1395 Puget Sound and adjacent waters. The 72 COLREGS shall apply on all waters of Puget Sound and adjacent waters, including Lake...

  6. 33 CFR 80.1395 - Puget Sound and adjacent waters.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Puget Sound and adjacent waters... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Thirteenth District § 80.1395 Puget Sound and adjacent waters. The 72 COLREGS shall apply on all waters of Puget Sound and adjacent waters, including Lake...

  7. Mass conservation: 1-D open channel flow equations

    USGS Publications Warehouse

    DeLong, Lewis L.

    1989-01-01

    Unsteady flow simulation in natural rivers is often complicated by meandering channels of compound section. Hydraulic properties and the length of the wetted channel may vary significantly as a meandering river inundates its adjacent floodplain. The one-dimensional, unsteady, open-channel flow equations can be extended to simulate floods in channels of compound section. It will be shown that equations derived from the addition of differential equations individually describing flow in main and overbank channels do not in general conserve mass when overbank and main channels are of different lengths.

  8. Optical Communications Channel Combiner

    NASA Technical Reports Server (NTRS)

    Quirk, Kevin J.; Quirk, Kevin J.; Nguyen, Danh H.; Nguyen, Huy

    2012-01-01

    NASA has identified deep-space optical communications links as an integral part of a unified space communication network in order to provide data rates in excess of 100 Mb/s. The distances and limited power inherent in a deep-space optical downlink necessitate the use of photon-counting detectors and a power-efficient modulation such as pulse position modulation (PPM). For the output of each photodetector, whether from a separate telescope or a portion of the detection area, a communication receiver estimates a log-likelihood ratio for each PPM slot. To realize the full effective aperture of these receivers, their outputs must be combined prior to information decoding. A channel combiner was developed to synchronize the log-likelihood ratio (LLR) sequences of multiple receivers, and then combines these into a single LLR sequence for information decoding. The channel combiner synchronizes the LLR sequences of up to three receivers and then combines these into a single LLR sequence for output. The channel combiner has three channel inputs, each of which takes as input a sequence of four-bit LLRs for each PPM slot in a codeword via a XAUI 10 Gb/s quad optical fiber interface. The cross-correlation between the channels LLR time series are calculated and used to synchronize the sequences prior to combining. The output of the channel combiner is a sequence of four-bit LLRs for each PPM slot in a codeword via a XAUI 10 Gb/s quad optical fiber interface. The unit is controlled through a 1 Gb/s Ethernet UDP/IP interface. A deep-space optical communication link has not yet been demonstrated. This ground-station channel combiner was developed to demonstrate this capability and is unique in its ability to process such a signal.

  9. 1. UPSTREAM VIEW OF THE SOUTH CHANNEL DAM, LOOKING EAST. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. UPSTREAM VIEW OF THE SOUTH CHANNEL DAM, LOOKING EAST. - Washington Water Power Company Post Falls Power Plant, South Channel Dam, West of intersection of Spokane & Fourth Streets, Post Falls, Kootenai County, ID

  10. 2. DOWNSTREAM VIEW OF THE SOUTH CHANNEL DAM, LOOKING WEST. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. DOWNSTREAM VIEW OF THE SOUTH CHANNEL DAM, LOOKING WEST. - Washington Water Power Company Post Falls Power Plant, South Channel Dam, West of intersection of Spokane & Fourth Streets, Post Falls, Kootenai County, ID

  11. Continuous equal channel angular pressing

    DOEpatents

    Zhu, Yuntian T.; Lowe, Terry C.; Valiev, Ruslan Z.; Raab, Georgy J.

    2006-12-26

    An apparatus that continuously processes a metal workpiece without substantially altering its cross section includes a wheel member having an endless circumferential groove, and a stationary constraint die that surrounds the wheel member, covers most of the length of the groove, and forms a passageway with the groove. The passageway has a rectangular shaped cross section. An abutment member projects from the die into the groove and blocks one end of the passageway. The wheel member rotates relative to the die in the direction toward the abutment member. An output channel in the die adjacent the abutment member has substantially the same cross section as the passageway. A metal workpiece is fed through an input channel into the passageway and carried in the groove by frictional drag in the direction towards the abutment member, and is extruded through the output channel without any substantial change in cross section.

  12. Dequantization Via Quantum Channels

    NASA Astrophysics Data System (ADS)

    Andersson, Andreas

    2016-08-01

    For a unital completely positive map {Φ} ("quantum channel") governing the time propagation of a quantum system, the Stinespring representation gives an enlarged system evolving unitarily. We argue that the Stinespring representations of each power {Φ^m} of the single map together encode the structure of the original quantum channel and provide an interaction-dependent model for the bath. The same bath model gives a "classical limit" at infinite time {mto∞} in the form of a noncommutative "manifold" determined by the channel. In this way, a simplified analysis of the system can be performed by making the large-m approximation. These constructions are based on a noncommutative generalization of Berezin quantization. The latter is shown to involve very fundamental aspects of quantum-information theory, which are thereby put in a completely new light.

  13. Dequantization Via Quantum Channels

    NASA Astrophysics Data System (ADS)

    Andersson, Andreas

    2016-10-01

    For a unital completely positive map {Φ} ("quantum channel") governing the time propagation of a quantum system, the Stinespring representation gives an enlarged system evolving unitarily. We argue that the Stinespring representations of each power {Φ^m} of the single map together encode the structure of the original quantum channel and provide an interaction-dependent model for the bath. The same bath model gives a "classical limit" at infinite time {mto∞} in the form of a noncommutative "manifold" determined by the channel. In this way, a simplified analysis of the system can be performed by making the large- m approximation. These constructions are based on a noncommutative generalization of Berezin quantization. The latter is shown to involve very fundamental aspects of quantum-information theory, which are thereby put in a completely new light.

  14. Entanglement-saving channels

    NASA Astrophysics Data System (ADS)

    Lami, L.; Giovannetti, V.

    2016-03-01

    The set of Entanglement Saving (ES) quantum channels is introduced and characterized. These are completely positive, trace preserving transformations which when acting locally on a bipartite quantum system initially prepared into a maximally entangled configuration, preserve its entanglement even when applied an arbitrary number of times. In other words, a quantum channel ψ is said to be ES if its powers ψn are not entanglement-breaking for all integers n. We also characterize the properties of the Asymptotic Entanglement Saving (AES) maps. These form a proper subset of the ES channels that is constituted by those maps that not only preserve entanglement for all finite n but which also sustain an explicitly not null level of entanglement in the asymptotic limit n → ∞. Structure theorems are provided for ES and for AES maps which yield an almost complete characterization of the former and a full characterization of the latter.

  15. Binaural unmasking with multiple adjacent masking electrodes in bilateral cochlear implant users

    PubMed Central

    Lu, Thomas; Litovsky, Ruth; Zeng, Fan-Gang

    2011-01-01

    Bilateral cochlear implant (BiCI) users gain an advantage in noisy situations from a second implant, but their bilateral performance falls short of normal hearing listeners. Channel interactions due to overlapping electrical fields between electrodes can impair speech perception, but its role in limiting binaural hearing performance has not been well characterized. To address the issue, binaural masking level differences (BMLD) for a 125 Hz tone in narrowband noise were measured using a pair of pitch-matched electrodes while simultaneously presenting the same masking noise to adjacent electrodes, representing a more realistic stimulation condition compared to prior studies that used only a single electrode pair. For five subjects, BMLDs averaged 8.9 ± 1.0 dB (mean ± s.e.) in single electrode pairs but dropped to 2.1 ± 0.4 dB when presenting noise on adjacent masking electrodes, demonstrating a negative impact of the additional maskers. Removing the masking noise from only the pitch-matched electrode pair not only lowered thresholds but also resulted in smaller BMLDs. The degree of channel interaction estimated from auditory nerve evoked potentials in three subjects was significantly and negatively correlated with BMLD. The data suggest that if the amount of channel interactions can be reduced, BiCI users may experience some performance improvements related to binaural hearing. PMID:21682415

  16. Comparison Between Eight- and Sixteen-Channel TEM Transceive Arrays for Body Imaging at 7 Tesla

    PubMed Central

    Snyder, CJ; DelaBarre, L; Moeller, S; Tian, J; Akgun, C; Van De Moortele, P-F; Bolan, PJ; Ugurbil, K; Vaughan, JT; Metzger, GJ

    2011-01-01

    Eight- and sixteen-channel transceive stripline/TEM body arrays were compared at 7 tesla (297 MHz) both in simulation and experimentally. Despite previous demonstrations of similar arrays for use in body applications, a quantitative comparison of the two configurations has not been undertaken to date. Results were obtained on a male pelvis for assessing transmit, SNR and parallel imaging performance and to evaluate local power deposition versus transmit B1 (B1+). All measurements and simulations were conducted after performing local B1+ phase shimming in the region of the prostate. Despite the additional challenges of decoupling immediately adjacent coils, the sixteen-channel array demonstrated improved or nearly equivalent performance to the eight-channel array based on the evaluation criteria. Experimentally, transmit performance and SNR were 22% higher for the sixteen-channel array while significantly increased reduction factors were achievable in the left-right direction for parallel imaging. Finite-difference time-domain simulations demonstrated similar results with respect to transmit and parallel imaging performance, however a higher transmit efficiency advantage of 33% was predicted. Simulations at both 3T and 7T verified the expected parallel imaging improvements with increasing field strength and showed that, for a specific B1+ shimming strategy employed, the sixteen-channel array exhibited lower local and global SAR for a given B1+. PMID:22102483

  17. Influences of channelization on discharge of suspended sediment and wetland vegetation in Kushiro Marsh, northern Japan

    NASA Astrophysics Data System (ADS)

    Nakamura, Futoshi; Sudo, Tadashi; Kameyama, Satoshi; Jitsu, Mieko

    1997-03-01

    The effects of wetlands on hydrology, water quality, and wildlife habitat are internationally recognized. Protecting the remaining wetlands is one of the most important environmental issues in many countries. However wetlands in Japan have been gradually shrinking due to agricultural development and urbanization, which generally lowers the groundwater level and introduces suspended sediment and sediment-associated nutrients into wetlands. We examined the influences of channelization on discharge of suspended sediment and wetland vegetation in Hokkaido, northern Japan. The impact of river channelization was confirmed not only by the sediment budgets but also by river aggradation or degradation after the channelization and by the resultant vegetational changes. The budgets of suspended sediment demonstrated that wash load was the predominant component accounting for 95% of the total suspended load delivered into the wetland. This suspended sediment was primarily transported into the wetland by flooding associated with heavy rainfall. Twenty-three percent of the wash load and 63% of the suspended bed material load were deposited in the channelized reach, which produced aggradation of about 2 m at the end of the reach. A shorting of the length of the channel, due to channelization of a meandering river, steepened the slope and enhanced the stream power to transport sediment. This steepening shifted the depositional zones of fine sediment 5 km downstream and aggraded the riverbed. Development of the watershed may increase not only the water discharge but also the amount of suspended sediments. The aggradation reduced the carrying capacity of the channel and caused sediment ladened water to flood over the wetlands. The fine sediment accumulated on the wetlands gradually altered the edaphic conditions and wetland vegetation. A low percentage (10 to 15%) of organic contents of wetlands' soil is more evidence indicating that the present condition is far different from

  18. English Channel

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The cloud covered earthscape of Northern Europe demonstrates the difficulty of photographing this elusive subject from space. The English Channel (51.0N, 1.5E) separating the British Islands from Europe is in the center of the scene. The white cliffs of Dover on the SE coast of the UK, the Thames River estuary and a partial view of the city of London can be seen on the north side of the Channel while the Normandy coast of France is to the south.

  19. Contrasting rainfall generated debris flows from adjacent watersheds at Forest Falls, southern California, USA

    USGS Publications Warehouse

    Morton, D.M.; Alvarez, R.M.; Ruppert, K.R.; Goforth, B.

    2008-01-01

    Debris flows are widespread and common in many steeply sloping areas of southern California. The San Bernardino Mountains community of Forest Falls is probably subject to the most frequently documented debris flows in southern California. Debris flows at Forest Falls are generated during short-duration high-intensity rains that mobilize surface material. Except for debris flows on two consecutive days in November 1965, all the documented historic debris flows have occurred during high-intensity summer rainfall, locally referred to as 'monsoon' or 'cloudburst' rains. Velocities of the moving debris range from about 5??km/h to about 90??km/h. Velocity of a moving flow appears to be essentially a function of the water content of the flow. Low velocity debris flows are characterized by steep snouts that, when stopped, have only small amounts of water draining from the flow. In marked contrast are high-velocity debris flows whose deposits more resemble fluvial deposits. In the Forest Falls area two adjacent drainage basins, Snow Creek and Rattlesnake Creek, have considerably different histories of debris flows. Snow Creek basin, with an area about three times as large as Rattlesnake Creek basin, has a well developed debris flow channel with broad levees. Most of the debris flows in Snow Creek have greater water content and attain higher velocities than those of Rattlesnake Creek. Most debris flows are in relative equilibrium with the geometry of the channel morphology. Exceptionally high-velocity flows, however, overshoot the channel walls at particularly tight channel curves. After overshooting the channel, the flows degrade the adjacent levee surface and remove trees and structures in the immediate path, before spreading out with decreasing velocity. As the velocity decreases the clasts in the debris flows pulverize the up-slope side of the trees and often imbed clasts in them. Debris flows in Rattlesnake Creek are relatively slow moving and commonly stop in the

  20. NOAA OTEC CWP (National Oceanic and Atmospheric Administration Ocean Thermal Energy Conversion Cold Water Pipe) at-sea test. Volume 3, part 1: Tabulation of the power spectra for selected channels

    NASA Astrophysics Data System (ADS)

    1983-11-01

    Data collected during the Ocean Thermal Energy Conversion (OTEC) Cold Water Pipe At-Sea Test was analyzed. Data presented included: (1)sensor factors and off sets and the data processing algorithms used to convert the recorded sensor measurements from electrical units to engineering units; (2) plots of the power spectra estimates obtained from a fast Fourier transform (FFT) analysis of selected channels; (3) plots of selected sensor measurements as a function of time; and (4) plots of bending strain along the pipe. The mean, root-mean-square (RMS) maximum, and minimum values at each depth are shown in each plot.

  1. Ius Chasma Tributary Valleys and Adjacent Plains

    NASA Technical Reports Server (NTRS)

    2006-01-01

    This image covers valley tributaries of Ius Chasma, as well as the plains adjacent to the valleys. Ius Chasma is one of several canyons that make up the Valles Marineris canyon system. Valles Marineris likely formed by extension associated with the growth of the large volcanoes and topographic high of Tharsis to the northwest. As the ground was pulled apart, large and deep gaps resulted in the valleys seen in the top and bottom of this HiRISE image. Ice that was once in the ground could have also melted to create additional removal of material in the formation of the valleys. HiRISE is able to see the rocks along the walls of both these valleys and also impact craters in the image. Rock layers that appear lower down in elevation appear rougher and are shedding boulders. Near the top of the walls and also seen in patches along the smooth plains are brighter layers. These brighter layers are not shedding boulders so they must represent a different kind of rock formed in a different kind of environment than those further down the walls. Because they are highest in elevation, the bright layers are youngest in age. HiRISE is able to see dozens of the bright layers, which are perhaps only a meter in thickness. Darker sand dunes and ripples cover most of the plains and fill the floors of impact craters.

    Image PSP_001351_1715 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on November 9, 2006. The complete image is centered at -8.3 degrees latitude, 275.4 degrees East longitude. The range to the target site was 254.3 km (158.9 miles). At this distance the image scale ranges from 25.4 cm/pixel (with 1 x 1 binning) to 101.8 cm/pixel (with 4 x 4 binning). The image shown here has been map-projected to 25 cm/pixel and north is up. The image was taken at a local Mars time of 3:32 PM and the scene is illuminated from the west with a solar incidence angle of 59 degrees, thus the sun was about

  2. Learning Non-Adjacent Regularities at Age 0 ; 7

    ERIC Educational Resources Information Center

    Gervain, Judit; Werker, Janet F.

    2013-01-01

    One important mechanism suggested to underlie the acquisition of grammar is rule learning. Indeed, infants aged 0 ; 7 are able to learn rules based on simple identity relations (adjacent repetitions, ABB: "wo fe fe" and non-adjacent repetitions, ABA: "wo fe wo", respectively; Marcus et al., 1999). One unexplored issue is…

  3. View of north side from exterior stairs of adjacent building, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of north side from exterior stairs of adjacent building, bottom cut off by fringed buildings, view facing south-southwest - U.S. Naval Base, Pearl Harbor, Industrial X-Ray Building, Off Sixth Street, adjacent to and south of Facility No. 11, Pearl City, Honolulu County, HI

  4. Delayed Acquisition of Non-Adjacent Vocalic Distributional Regularities

    ERIC Educational Resources Information Center

    Gonzalez-Gomez, Nayeli; Nazzi, Thierry

    2016-01-01

    The ability to compute non-adjacent regularities is key in the acquisition of a new language. In the domain of phonology/phonotactics, sensitivity to non-adjacent regularities between consonants has been found to appear between 7 and 10 months. The present study focuses on the emergence of a posterior-anterior (PA) bias, a regularity involving two…

  5. SPERTI Reactor Pit Building (PER605). Earth shielding protect adjacent Instrument ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    SPERT-I Reactor Pit Building (PER-605). Earth shielding protect adjacent Instrument Cell (PER-606). Security fencing surrounds complex, to which gate entry is provided next to Guard House (PER-607). Note gravel road leading to control area. Earth-covered conduit leads from instrument cell to terminal building out of view. Photographer: R.G. Larsen. Date: June 22, 1955. INEEL negative no. 55-1701 - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

  6. Solution structure of the potassium channel inhibitor agitoxin 2: caliper for probing channel geometry.

    PubMed Central

    Krezel, A. M.; Kasibhatla, C.; Hidalgo, P.; MacKinnon, R.; Wagner, G.

    1995-01-01

    The structure of the potassium channel blocker agitoxin 2 was solved by solution NMR methods. The structure consists of a triple-stranded antiparallel beta-sheet and a single helix covering one face of the beta-sheet. The cysteine side chains connecting the beta-sheet and the helix form the core of the molecule. One edge of the beta-sheet and the adjacent face of the helix form the interface with the Shaker K+ channel. The fold of agitoxin is homologous to the previously determined folds of scorpion venom toxins. However, agitoxin 2 differs significantly from the other channel blockers in the specificity of its interactions. This study was thus focused on a precise characterization of the surface residues at the face of the protein interacting with the Shaker K+ channel. The rigid toxin molecule can be used to estimate dimensions of the potassium channel. Surface-exposed residues, Arg24, Lys27, and Arg31 of the beta-sheet, have been identified from mutagenesis studies as functionally important for blocking the Shaker K+ channel. The sequential and spatial locations of Arg24 and Arg31 are not conserved among the homologous toxins. Knowledge on the details of the channel-binding sites of agitoxin 2 formed a basis for site-directed mutagenesis studies of the toxin and the K+ channel sequences. Observed interactions between mutated toxin and channel are being used to elucidate the channel structure and mechanisms of channel-toxin interactions. PMID:8520473

  7. The channels of Mars

    NASA Technical Reports Server (NTRS)

    Baker, Victor R.

    1988-01-01

    The geomorphology of Mars is discussed, focusing on the Martian channels. The great flood channels of Mars, the processes of channel erosion, and dendritic channel networks, are examined. The topography of the Channeled Scabland region of the northwestern U.S. is described and compared to the Martian channels. The importance of water in the evolution of the channel systems is considered.

  8. Measurement of brightness temperature of two-dimensional electron gas in channel of a high electron mobility transistor at ultralow dissipation power

    NASA Astrophysics Data System (ADS)

    Korolev, A. M.; Shulga, V. M.; Turutanov, O. G.; Shnyrkov, V. I.

    2016-07-01

    A technically simple and physically clear method is suggested for direct measurement of the brightness temperature of two-dimensional electron gas (2DEG) in the channel of a high electron mobility transistor (HEMT). The usage of the method was demonstrated with the pseudomorphic HEMT as a specimen. The optimal HEMT dc regime, from the point of view of the "back action" problem, was found to belong to the unsaturated area of the static characteristics possibly corresponding to the ballistic electron transport mode. The proposed method is believed to be a convenient tool to explore the ballistic transport, electron diffusion, 2DEG properties and other electrophysical processes in heterostructures.

  9. Research and development studies for MHD/coal power flow train components. Part II. Diagnostics and instrumentation MHD channel combutor. Progres report. [Flow calculations for combustors

    SciTech Connect

    Bloom, M.H.; Lederman, S.; Sforza, P.; Matalon, M.

    1980-01-01

    This is Part II of the Technical Progress Report on Tasks II-IV of the subject contract. It deals sequentially with Diagnostics and Instrumentation, the MHD Channel and the Combustor. During this period, a significant effort has gone into establishing a schematic design of a laser diagnostic system which can be applied to the flow-train of the MHD system, and to acquiring, assembling and shaking down a laboratory set-up upon which a prototype can be based. With further reference to the MHD Channel, a model analysis has been initiated of the two-dimensional MHD boundary layer between two electrodes in the limit of small magnetic Reynolds numbers with negligible effect of the flow on the applied magnetic field. An objective of this model study is the assessment of variations in initial conditions on the boundary layer behavior. Finally, the problem of combustion modeling has been studied on an initial basis. The open reports on this subject depict a high degree of empiricism, centering attention on global behavior mainly. A quasi-one-dimensional model code has been set-up to check some of the existing estimates. Also a code for equilibrium combustion has been activated.

  10. Trends in developed land cover adjacent to habitat for threatened salmon in Puget Sound, Washington, USA.

    PubMed

    Bartz, Krista K; Ford, Michael J; Beechie, Timothy J; Fresh, Kurt L; Pess, George R; Kennedy, Robert E; Rowse, Melinda L; Sheer, Mindi

    2015-01-01

    For widely distributed species at risk, such as Pacific salmon (Oncorhynchus spp.), habitat monitoring is both essential and challenging. Only recently have widespread monitoring programs been implemented for salmon habitat in the Pacific Northwest. Remote sensing data, such as Landsat images, are therefore a useful way to evaluate trends prior to the advent of species-specific habitat monitoring programs. We used annual (1986-2008) land cover maps created from Landsat images via automated algorithms (LandTrendr) to evaluate trends in developed (50-100% impervious) land cover in areas adjacent to five types of habitat utilized by Chinook salmon (O. tshawytscha) in the Puget Sound region of Washington State, U.S.A. For the region as a whole, we found significant increases in developed land cover adjacent to each of the habitat types evaluated (nearshore, estuary, mainstem channel, tributary channel, and floodplain), but the increases were small (<1% total increase from 1986 to 2008). For each habitat type, the increasing trend changed during the time series. In nearshore, mainstem, and floodplain areas, the rate of increase in developed land cover slowed in the latter portion of the time series, while the opposite occurred in estuary and tributary areas. Watersheds that were already highly developed in 1986 tended to have higher rates of development than initially less developed watersheds. Overall, our results suggest that developed land cover in areas adjacent to Puget Sound salmon habitat has increased only slightly since 1986 and that the rate of change has slowed near some key habitat types, although this has occurred within the context of a degraded baseline condition. PMID:25923327

  11. Trends in developed land cover adjacent to habitat for threatened salmon in Puget Sound, Washington, USA.

    PubMed

    Bartz, Krista K; Ford, Michael J; Beechie, Timothy J; Fresh, Kurt L; Pess, George R; Kennedy, Robert E; Rowse, Melinda L; Sheer, Mindi

    2015-01-01

    For widely distributed species at risk, such as Pacific salmon (Oncorhynchus spp.), habitat monitoring is both essential and challenging. Only recently have widespread monitoring programs been implemented for salmon habitat in the Pacific Northwest. Remote sensing data, such as Landsat images, are therefore a useful way to evaluate trends prior to the advent of species-specific habitat monitoring programs. We used annual (1986-2008) land cover maps created from Landsat images via automated algorithms (LandTrendr) to evaluate trends in developed (50-100% impervious) land cover in areas adjacent to five types of habitat utilized by Chinook salmon (O. tshawytscha) in the Puget Sound region of Washington State, U.S.A. For the region as a whole, we found significant increases in developed land cover adjacent to each of the habitat types evaluated (nearshore, estuary, mainstem channel, tributary channel, and floodplain), but the increases were small (<1% total increase from 1986 to 2008). For each habitat type, the increasing trend changed during the time series. In nearshore, mainstem, and floodplain areas, the rate of increase in developed land cover slowed in the latter portion of the time series, while the opposite occurred in estuary and tributary areas. Watersheds that were already highly developed in 1986 tended to have higher rates of development than initially less developed watersheds. Overall, our results suggest that developed land cover in areas adjacent to Puget Sound salmon habitat has increased only slightly since 1986 and that the rate of change has slowed near some key habitat types, although this has occurred within the context of a degraded baseline condition.

  12. Dynamics of relative entropy of coherence under Markovian channels

    NASA Astrophysics Data System (ADS)

    Situ, Haozhen; Hu, Xueyuan

    2016-08-01

    We study the relative entropy of coherence under the effect of certain one-qubit channels that are Markovian and noisy. The cohering power and decohering power of phase damping, amplitude damping, flip and depolarizing channels are analytically calculated. For phase damping channel, the decohering power on the x, y, and z bases is the same. The same phenomenon is observed for the flip and depolarizing channels. Further, we show that weak measurement and its reversal can be employed to suppress the decohering power of the amplitude damping channel.

  13. Fluid channeling system

    NASA Technical Reports Server (NTRS)

    Davis, Donald Y. (Inventor); Hitch, Bradley D. (Inventor)

    1994-01-01

    A fluid channeling system includes a fluid ejector, a heat exchanger, and a fluid pump disposed in series flow communication The ejector includes a primary inlet for receiving a primary fluid, and a secondary inlet for receiving a secondary fluid which is mixed with the primary fluid and discharged therefrom as ejector discharge. Heat is removed from the ejector discharge in the heat exchanger, and the heat exchanger discharge is compressed in the fluid pump and channeled to the ejector secondary inlet as the secondary fluid In an exemplary embodiment, the temperature of the primary fluid is greater than the maximum operating temperature of a fluid motor powering the fluid pump using a portion of the ejector discharge, with the secondary fluid being mixed with the primary fluid so that the ejector discharge temperature is equal to about the maximum operating temperature of the fluid motor.

  14. Lock 4 View east of lock wall and adjacent ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Lock 4 - View east of lock wall and adjacent roadway built atop tow path. The gate pocket can be seen at center. - Savannah & Ogeechee Barge Canal, Between Ogeechee & Savannah Rivers, Savannah, Chatham County, GA

  15. 14. Charles Acey Cobb standing adjacent to the fish screen ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. Charles Acey Cobb standing adjacent to the fish screen he designed and installed in the Congdon Canal, facing southeast. Photo dates ca. late 1920's. - Congdon Canal, Fish Screen, Naches River, Yakima, Yakima County, WA

  16. 3. View of north side of house facing from adjacent ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. View of north side of house facing from adjacent vacant property. Original wood lap siding and trim is covered by aluminum siding. Recessed side porch is in middle. - 645 South Eighteenth Street (House), Louisville, Jefferson County, KY

  17. View from water showing south facade and adjacent boat slips ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View from water showing south facade and adjacent boat slips (Facility Nos. S375 & S376) - U.S. Naval Base, Pearl Harbor, Boat House, Hornet Avenue at Independence Street, Pearl City, Honolulu County, HI

  18. OBLIQUE OF SOUTHWEST END AND SOUTHEAST SIDE, WITH ADJACENT FACILITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OBLIQUE OF SOUTHWEST END AND SOUTHEAST SIDE, WITH ADJACENT FACILITY 391 IN THE FOREGROUND. - U.S. Naval Base, Pearl Harbor, Joint Intelligence Center, Makalapa Drive in Makalapa Administration Area, Pearl City, Honolulu County, HI

  19. Interior building details of Building A, dungeon cell adjacent to ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior building details of Building A, dungeon cell adjacent to northwest cell: granite and brick threshold, poured concrete floors, plastered finished walls, vaulted veiling; northwesterly view - San Quentin State Prison, Building 22, Point San Quentin, San Quentin, Marin County, CA

  20. View of viaduct, looking SE from roof of adjacent parking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of viaduct, looking SE from roof of adjacent parking garage. - Mulberry Street Viaduct, Spanning Paxton Creek & Cameron Street (State Route 230) at Mulberry Street (State Route 3012), Harrisburg, Dauphin County, PA

  1. Cement Leakage into Adjacent Vertebral Body Following Percutaneous Vertebroplasty

    PubMed Central

    Park, Jae Hoo; Kim, Hyeun Sung

    2016-01-01

    Percutaneous vertebroplasty (PV) is a minimally invasive procedure for osteoporotic vertebral compression fractures that fail to respond to conventional conservative treatment. It significantly improves intolerable back pain within hours, and has a low complication rate. Although rare, PV is not free of complications, most of which are directly related to cement leakage. Because of its association with new adjacent fracture, the importance of cement leakage into the adjacent disc space is paramount. Here, we report an interesting case of cement leakage into the adjacent upper vertebral body as well as disc space following PV. To the best of our knowledge, there has been no report of cement leakage into the adjacent vertebral body following PV. This rare case is presented along with a review of the literature. PMID:27437018

  2. 2. DETAIL OF CONTROL GATE ADJACENT TO LIFT LOCK NO. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. DETAIL OF CONTROL GATE ADJACENT TO LIFT LOCK NO. 7; THIS CONTROL GATE IS A 1980s RECONSTRUCTION. - Illinois & Michigan Canal, Lift Lock No. 7 & Control Gate, East side of DuPage River, Channahon, Will County, IL

  3. 33. HISTORIC PLAQUE MARKING WHERE JOHNSTON DIED, ADJACENT TO PATHWAY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    33. HISTORIC PLAQUE MARKING WHERE JOHNSTON DIED, ADJACENT TO PATHWAY WITH CONCRETE CULVERT LEADING NORTH OUT OF RAVINE TOWARD JOHNSTON MEMORIAL SITE. VIEW NW. - Shiloh National Military Park Tour Roads, Shiloh, Hardin County, TN

  4. VIEW OF LAMP FIXTURE (EXTERIOR) ADJACENT TO ENTRANCE AT SOUTHWEST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF LAMP FIXTURE (EXTERIOR) ADJACENT TO ENTRANCE AT SOUTHWEST CORNER OF BUILDING 23, FACING NORTH - Roosevelt Base, Auditorium-Gymnasium, West Virginia Street between Richardson & Reeves Avenues, Long Beach, Los Angeles County, CA

  5. VIEW OF NORTHERN AND EASTERN SIDES FROM PARKING LOT ADJACENT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF NORTHERN AND EASTERN SIDES FROM PARKING LOT ADJACENT TO BUILDING 199 (POLICE STATION) - U.S. Naval Base, Pearl Harbor, Post Office, Avenue A near Eleventh Avenue, Pearl City, Honolulu County, HI

  6. 73. PASSAGE ADJACENT TO ROOM 232, EAST WING, SECOND FLOOR, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    73. PASSAGE ADJACENT TO ROOM 232, EAST WING, SECOND FLOOR, LOOKING WEST BY NORTHWEST, SHOWING EASTERNMOST ARCH OF FORMER GREAT HALL NORTH ARCADE - Smithsonian Institution Building, 1000 Jefferson Drive, between Ninth & Twelfth Streets, Southwest, Washington, District of Columbia, DC

  7. 1. A BRICK AND CONCRETE FAN HOUSING ADJACENT TO ONE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. A BRICK AND CONCRETE FAN HOUSING ADJACENT TO ONE OF THE ADIT OPENINGS (VIEW TO THE NORTH). - Foster Gulch Mine, Fan Housing, Bear Creek 1 mile Southwest of Town of Bear Creek, Red Lodge, Carbon County, MT

  8. GENERAL VIEW OF WAREHOUSE ADJACENT TO BATCH PLANT, LOOKING NORTHWEST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    GENERAL VIEW OF WAREHOUSE ADJACENT TO BATCH PLANT, LOOKING NORTHWEST FROM DREY STREET PLANT, INSIDE WELCOME WALL - Chambers Window Glass Company, Warehouse & Shipping, North of Drey (Nineteenth) Street, West of Constitution Boulevard, Arnold, Westmoreland County, PA

  9. 10. SLATE PATIO ADJACENT TO SOUTH PORCH OF HOUSE, FROM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. SLATE PATIO ADJACENT TO SOUTH PORCH OF HOUSE, FROM SOUTHEAST CORNER OF REAR PORCH. SHED IS VISIBLE IN BACKGROUND. - Butt Valley Dam, Gate Tender's House, Butt Valley Reservoir Road, Caribou, Plumas County, CA

  10. Detail of fire alarm boxes located adjacent to the entrance ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of fire alarm boxes located adjacent to the entrance of the northwest wing - Mare Island Naval Shipyard, Guard House & Barracks, Railroad Avenue near Eighteenth Street, Vallejo, Solano County, CA

  11. Detail exterior view looking north showing piping system adjacent to ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail exterior view looking north showing piping system adjacent to engine house. Gas cooling system is on far right. - Burnsville Natural Gas Pumping Station, Saratoga Avenue between Little Kanawha River & C&O Railroad line, Burnsville, Braxton County, WV

  12. 1. Ninth Street (west) facade. Adjacent on the north is ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Ninth Street (west) facade. Adjacent on the north is the 9th Street facade of 816 E Street. Both buildings were originally one property. - Riley Building, Rendezvous Adult Magazines & Films, 437 Ninth Street, Northwest, Washington, District of Columbia, DC

  13. 2. THREEQUARTER VIEW FROM ADJACENT ACCESS ROAD SHOWING THREE SPANS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. THREE-QUARTER VIEW FROM ADJACENT ACCESS ROAD SHOWING THREE SPANS AND NORTHWEST APPROACH SPANS, LOOKING SOUTHEAST - Red River Bridge, Spanning Red River at U.S. Highway 82, Garland, Miller County, AR

  14. 31. VAL, DETAIL OF LOADING PLATFORM ADJACENT TO LAUNCHER BRIDGE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. VAL, DETAIL OF LOADING PLATFORM ADJACENT TO LAUNCHER BRIDGE LOOKING WEST. - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  15. Basement, room 23, looking southwest into two adjacent offices with ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Basement, room 23, looking southwest into two adjacent offices with soundproof walls and pedestal flooring - March Air Force Base, Strategic Air Command, Combat Operations Center, 5220 Riverside Drive, Moreno Valley, Riverside County, CA

  16. 7. August, 1970 9 ORANGE STREET, ADJACENT TO UNITARIAN CHURCH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. August, 1970 9 ORANGE STREET, ADJACENT TO UNITARIAN CHURCH (NOT IN STUDY AREA) - Orange & Union Streets Neighborhood Study, 8-31 Orange Street, 9-21 Union Street & Stone Alley, Nantucket, Nantucket County, MA

  17. Brick incinerator structure located adjacent to "motor courts." This example ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Brick incinerator structure located adjacent to "motor courts." This example is located between Buildings 26 and 27. Facing northeast - Harbor Hills Housing Project, 26607 Western Avenue, Lomita, Los Angeles County, CA

  18. Carbon Monoxide Hazards from Small Gasoline Powered Engines

    MedlinePlus

    ... where he had been working with an 8-horse-power, gasoline-powered pump. Doors adjacent to the ... treated for CO poisoning after using two 8 horse-power, gasoline-powered, pressure washers in a poorly ...

  19. Arroyo channel head evolution in a flash-flood-dominated discontinuous ephemeral stream system

    USGS Publications Warehouse

    DeLong, Stephen B.; Johnson, Joel P.L.; Whipple, Kelin X.

    2014-01-01

    We study whether arroyo channel head retreat in dryland discontinuous ephemeral streams is driven by surface runoff, seepage erosion, mass wasting, or some combination of these hydrogeomorphic processes. We monitored precipitation, overland flow, soil moisture, and headcut migration over several seasonal cycles at two adjacent rangeland channel heads in southern Arizona. Erosion occurred by headward retreat of vertical to overhanging faces, driven dominantly by surface runoff. No evidence exists for erosion caused by shallow-groundwater–related processes, even though similar theater-headed morphologies are sometimes attributed to seepage erosion by emerging groundwater. At our field site, vertical variation in soil shear strength influenced the persistence of the characteristic theater-head form. The dominant processes of erosion included removal of grains and soil aggregates during even very shallow (1–3 cm) overland flow events by runoff on vertical to overhanging channel headwalls, plunge-pool erosion during higher-discharge runoff events, immediate postrunoff wet mass wasting, and minor intra-event dry mass wasting on soil tension fractures developing subparallel to the headwall. Multiple stepwise linear regression indicates that the migration rate is most strongly correlated with flow duration and total precipitation and is poorly correlated with peak flow depth or time-integrated flow depth. The studied channel heads migrated upslope with a self-similar morphologic form under a wide range of hydrological conditions, and the most powerful flash floods were not always responsible for the largest changes in landscape form in this environment. 

  20. Adjacent Segment Disease Perspective and Review of the Literature

    PubMed Central

    Saavedra-Pozo, Fanor M.; Deusdara, Renato A. M.; Benzel, Edward C.

    2014-01-01

    Background Adjacent segment disease has become a common topic in spine surgery circles because of the significant increase in fusion surgery in recent years and the development of motion preservation technologies that theoretically should lead to a decrease in this pathology. The purpose of this review is to organize the evidence available in the current literature on this subject. Methods For this literature review, a search was conducted in PubMed with the following keywords: adjacent segment degeneration and disease. Selection, review, and analysis of the literature were completed according to level of evidence. Results The PubMed search identified 850 articles, from which 41 articles were selected and reviewed. The incidence of adjacent segment disease in the cervical spine is close to 3% without a significant statistical difference between surgical techniques (fusion vs arthroplasty). Authors report the incidence of adjacent segment disease in the lumbar spine to range from 2% to 14%. Damage to the posterior ligamentous complex and sagittal imbalances are important risk factors for both degeneration and disease. Conclusion Insufficient evidence exists at this point to support the idea that total disc arthroplasty is superior to fusion procedures in minimizing the incidence of adjacent segment disease. The etiology is most likely multifactorial but it is becoming abundantly clear that adjacent segment disease is not caused by motion segment fusion alone. Fusion plus the presence of abnormal end-fusion alignment appears to be a major factor in creating end-fusion stresses that result in adjacent segment degeneration and subsequent disease. The data presented cast further doubt on previously established rationales for total disc arthroplasty, at least with regard to the effect of total disc arthroplasty on adjacent segment degeneration pathology. PMID:24688337

  1. GEOMORPHIC CONTROLS ON C AND N PROCESSING IN A RESTORED URBAN STREAM; POWER POINT PRESENTATION

    EPA Science Inventory

    Stream channel incision due to hydraulic alteration stemming from urbanization may cause a disconnection between the stream channel and the adjacent floodplain. This disconnection may inhibit removal of nitrate via denitrification and/or stimulate nitrate production through nitr...

  2. Analysis of adjacent segment reoperation after lumbar total disc replacement

    PubMed Central

    Rainey, Scott; Blumenthal, Scott L.; Zigler, Jack E.; Guyer, Richard D.; Ohnmeiss, Donna D.

    2012-01-01

    Background Fusion has long been used for treating chronic back pain unresponsive to nonoperative care. However, potential development of adjacent segment degeneration resulting in reoperation is a concern. Total disc replacement (TDR) has been proposed as a method for addressing back pain and preventing or reducing adjacent segment degeneration. The purpose of the study was to determine the reoperation rate at the segment adjacent to a level implanted with a lumbar TDR and to analyze the pre-TDR condition of the adjacent segment. Methods This study was based on a retrospective review of charts and radiographs from a consecutive series of 1000 TDR patients to identify those who underwent reoperation because of adjacent segment degeneration. Some of the patients were part of randomized studies comparing TDR with fusion. Adjacent segment reoperation data were also collected from 67 patients who were randomized to fusion in those studies. The condition of the adjacent segment before the index surgery was compared with its condition before reoperation based on radiographs, magnetic resonance imaging (MRI), and computed tomography. Results Of the 1000 TDR patients, 20 (2.0%) underwent reoperation. The mean length of time from arthroplasty to reoperation was 28.3 months (range, 0.5–85 months). Of the adjacent segments evaluated on preoperative MRI, 38.8% were normal, 38.8% were moderately diseased, and 22.2% were classified as having severe degeneration. None of these levels had a different grading at the time of reoperation compared with the pre-TDR MRI study. Reoperation for adjacent segment degeneration was performed in 4.5% of the fusion patients. Conclusions The 2.0% rate of adjacent segment degeneration resulting in reoperation in this study is similar to the 2.0% to 2.8% range in other studies and lower than the published rates of 7% to 18% after lumbar fusion. By carefully assessing the presence of pre-existing degenerative changes before performing arthroplasty

  3. Microbial Senses and Ion Channels

    NASA Astrophysics Data System (ADS)

    Kung, Ching; Zhou, Xin-Liang; Su, Zhen-Wei; Haynes, W. John; Loukin, Sephan H.; Saimi, Yoshiro

    The complexity of animals and plants is due largely to cellular arrangement. The structures and activities of macromolecules had, however, evolved in early microbes long before the appearance of this complexity. Among such molecules are those that sense light, heat, force, water, and ligands. Though historically and didactically associated with the nervous system, ion channels also have deep evolutionary roots. For example, force sensing with channels, which likely began as water sensing through membrane stretch generated by osmotic pressure, must be ancient and is universal in extant species. Extant microbial species, such as the model bacterium Escherichia coli and yeast Saccharomyces cerevisiae, are equipped with stretch-activated channels. The ion channel proteins MscL and MscS show clearly that these bacterial channels receive stretch forces from the lipid bilayer. TRPY1, the mechanosensitive channel in yeast, is being developed towards a similar basic understanding of channels of the TRP (transientreceptor- potential) superfamily. TRPY1 resides in the vacuolar membrane and releases Ca2+ from the vacuole to the cytoplasm upon hyperosmotic shock. Unlike in most TRP preparations from animals, the mechanosensitivity of TRPY1 can be examined directly under patch clamp in either whole-vacuole mode or excised patch mode. The combination of direct biophysical examination in vitro with powerful microbial genetics in vivo should complement the study of mechanosensations of complex animals and plants.

  4. Magnetohydrodynamic energy conversion by using convexly divergent channel

    SciTech Connect

    Murakami, Tomoyuki; Okuno, Yoshihiro

    2009-12-21

    We describe a magnetohydrodynamic (MHD) electrical power generator equipped with a convexly divergent channel, as determined through shock-tunnel-based experiments. The quality of MHD power-generating plasma and the energy conversion efficiency in the convexly divergent channel are compared with those from previous linearly divergent channel. The divergence enhancement in the channel upstream is effective for suppressing an excessive increase in static pressure, whereby notably high isentropic efficiency is achieved.

  5. Ion channeling revisited

    SciTech Connect

    Doyle, Barney Lee; Corona, Aldo; Nguyen, Anh

    2014-09-01

    A MS Excel program has been written that calculates accidental, or unintentional, ion channeling in cubic bcc, fcc and diamond lattice crystals or polycrystalline materials. This becomes an important issue when simulating the creation by energetic neutrons of point displacement damage and extended defects using beams of ions. All of the tables and graphs in the three Ion Beam Analysis Handbooks that previously had to be manually looked up and read from were programed into Excel in handy lookup tables, or parameterized, for the case of the graphs, using rather simple exponential functions with different powers of the argument. The program then offers an extremely convenient way to calculate axial and planar half-angles and minimum yield or dechanneling probabilities, effects on half-angles of amorphous overlayers, accidental channeling probabilities for randomly oriented crystals or crystallites, and finally a way to automatically generate stereographic projections of axial and planar channeling half-angles. The program can generate these projections and calculate these probabilities for axes and [hkl] planes up to (555).

  6. A Micromechanical RF Channelizer

    NASA Astrophysics Data System (ADS)

    Akgul, Mehmet

    The power consumption of a radio generally goes as the number and strength of the RF signals it must process. In particular, a radio receiver would consume much less power if the signal presented to its electronics contained only the desired signal in a tiny percent bandwidth frequency channel, rather than the typical mix of signals containing unwanted energy outside the desired channel. Unfortunately, a lack of filters capable of selecting single channel bandwidths at RF forces the front-ends of contemporary receivers to accept unwanted signals, and thus, to operate with sub-optimal efficiency. This dissertation focuses on the degree to which capacitive-gap transduced micromechanical resonators can achieve the aforementioned RF channel-selecting filters. It aims to first show theoretically that with appropriate scaling capacitive-gap transducers are strong enough to meet the needed coupling requirements; and second, to fully detail an architecture and design procedure needed to realize said filters. Finally, this dissertation provides an actual experimentally demonstrated RF channel-select filter designed using the developed procedures and confirming theoretical predictions. Specifically, this dissertation introduces four methods that make possible the design and fabrication of RF channel-select filters. The first of these introduces a small-signal equivalent circuit for parallel-plate capacitive-gap transduced micromechanical resonators that employs negative capacitance to model the dependence of resonance frequency on electrical stiffness in a way that facilitates the analysis of micromechanical circuits loaded with arbitrary electrical impedances. The new circuit model not only correctly predicts the dependence of electrical stiffness on the impedances loading the input and output electrodes of parallel-plate capacitive-gap transduced micromechanical device, but does so in a visually intuitive way that identifies current drive as most appropriate for

  7. 3. CREST OF THE SOUTH CHANNEL DAM, SHOWING BLOCK HOUSE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. CREST OF THE SOUTH CHANNEL DAM, SHOWING BLOCK HOUSE (NOT ORIGINAL) COVERING THE ELECTRICALLY POWERED GATE-LIFTING MECHANISM THAT REPLACED THE ORIGINAL HAND-OPERATED LIFTING DEVICE, LOOKING NORTH. - Washington Water Power Company Post Falls Power Plant, South Channel Dam, West of intersection of Spokane & Fourth Streets, Post Falls, Kootenai County, ID

  8. Influence of bathymetry on hydrography and circulation at the region between an estuary mouth and the adjacent continental shelf

    NASA Astrophysics Data System (ADS)

    Lee, Jungwoo; Valle-Levinson, Arnoldo

    2012-06-01

    Bathymetry effects on the flow field at the transition between idealized estuaries and the adjacent ocean are studied with the Regional Ocean Modeling System (ROMS). Estuary width, depth, and channel direction at the shelf are used to determine flow characteristics in and out of an idealized estuary. The idealized estuary connects to an upstream boundary, where freshwater discharges, and an offshore tidal boundary. Tidally averaged salinity and flow structures are examined at the estuary mouth. A recirculation feature directly affects flow at the estuary mouth, especially in shallow and wide estuarine systems. The recirculation retards the exchange flow near the edges of the estuary mouth and consequently allows strengthening of the flow in the middle. The geometric shape of the estuarine channel affects the strength of the residual flow at the estuary mouth. The presence of an extended submarine channel on the shelf enhances the baroclinic circulation and stratification, and maximizes the salinity intrusion length without additional external forces. The direction of this submarine channel affects the exchange flow structures at the estuary/ocean transition zone in such a way that the salinity intrusion length increases with a left-turning channel (in the Kelvin wave sense of the fresh water flow direction). This is attributed to the competition between centrifugal and Coriolis forces. Flow characteristics described by the Kelvin and Ekman number, which outline channel geometric effects, are similar to previous studies.

  9. Laplacian versus adjacency matrix in quantum walk search

    NASA Astrophysics Data System (ADS)

    Wong, Thomas G.; Tarrataca, Luís; Nahimov, Nikolay

    2016-10-01

    A quantum particle evolving by Schrödinger's equation contains, from the kinetic energy of the particle, a term in its Hamiltonian proportional to Laplace's operator. In discrete space, this is replaced by the discrete or graph Laplacian, which gives rise to a continuous-time quantum walk. Besides this natural definition, some quantum walk algorithms instead use the adjacency matrix to effect the walk. While this is equivalent to the Laplacian for regular graphs, it is different for non-regular graphs and is thus an inequivalent quantum walk. We algorithmically explore this distinction by analyzing search on the complete bipartite graph with multiple marked vertices, using both the Laplacian and adjacency matrix. The two walks differ qualitatively and quantitatively in their required jumping rate, runtime, sampling of marked vertices, and in what constitutes a natural initial state. Thus the choice of the Laplacian or adjacency matrix to effect the walk has important algorithmic consequences.

  10. Laplacian versus adjacency matrix in quantum walk search

    NASA Astrophysics Data System (ADS)

    Wong, Thomas G.; Tarrataca, Luís; Nahimov, Nikolay

    2016-06-01

    A quantum particle evolving by Schrödinger's equation contains, from the kinetic energy of the particle, a term in its Hamiltonian proportional to Laplace's operator. In discrete space, this is replaced by the discrete or graph Laplacian, which gives rise to a continuous-time quantum walk. Besides this natural definition, some quantum walk algorithms instead use the adjacency matrix to effect the walk. While this is equivalent to the Laplacian for regular graphs, it is different for non-regular graphs and is thus an inequivalent quantum walk. We algorithmically explore this distinction by analyzing search on the complete bipartite graph with multiple marked vertices, using both the Laplacian and adjacency matrix. The two walks differ qualitatively and quantitatively in their required jumping rate, runtime, sampling of marked vertices, and in what constitutes a natural initial state. Thus the choice of the Laplacian or adjacency matrix to effect the walk has important algorithmic consequences.

  11. On the Adjacent Eccentric Distance Sum Index of Graphs

    PubMed Central

    Qu, Hui; Cao, Shujuan

    2015-01-01

    For a given graph G, ε(v) and deg(v) denote the eccentricity and the degree of the vertex v in G, respectively. The adjacent eccentric distance sum index of a graph G is defined as ξsv(G)=∑v∈V(G)ε(v)D(v)deg(v), where D(v)=∑u∈V(G)d(u,v) is the sum of all distances from the vertex v. In this paper we derive some bounds for the adjacent eccentric distance sum index in terms of some graph parameters, such as independence number, covering number, vertex connectivity, chromatic number, diameter and some other graph topological indices. PMID:26091095

  12. Molecular disorganization of axons adjacent to human lacunar infarcts.

    PubMed

    Hinman, Jason D; Lee, Monica D; Tung, Spencer; Vinters, Harry V; Carmichael, S Thomas

    2015-03-01

    Cerebral microvascular disease predominantly affects brain white matter and deep grey matter, resulting in ischaemic damage that ranges from lacunar infarcts to white matter hyperintensities seen on magnetic resonance imaging. These lesions are common and result in both clinical stroke syndromes and accumulate over time, resulting in cognitive deficits and dementia. Magnetic resonance imaging studies suggest that these lesions progress over time, accumulate adjacent to prior lesions and have a penumbral region susceptible to further injury. The pathological correlates of this adjacent injury in surviving myelinated axons have not been previously defined. In this study, we sought to determine the molecular organization of axons in tissue adjacent to lacunar infarcts and in the regions surrounding microinfarcts, by determining critical elements in axonal function: the morphology and length of node of Ranvier segments and adjacent paranodal segments. We examined post-mortem brain tissue from six patients with lacunar infarcts and tissue from two patients with autosomal dominant retinal vasculopathy and cerebral leukoencephalopathy (previously known as hereditary endotheliopathy with retinopathy, nephropathy and stroke) who accumulate progressive white matter ischaemic lesions in the form of lacunar and microinfarcts. In axons adjacent to lacunar infarcts yet extending up to 150% of the infarct diameter away, both nodal and paranodal length increase by ∼20% and 80%, respectively, reflecting a loss of normal cell-cell adhesion and signalling between axons and oligodendrocytes. Using premorbid magnetic resonance images, brain regions from patients with retinal vasculopathy and cerebral leukoencephalopathy that harboured periventricular white matter hyperintensities were selected and the molecular organization of axons was determined within these regions. As in regions adjacent to lacunar infarcts, nodal and paranodal length in white matter of these patients is

  13. Molecular disorganization of axons adjacent to human lacunar infarcts

    PubMed Central

    Lee, Monica D.; Tung, Spencer; Vinters, Harry V.; Carmichael, S. Thomas

    2015-01-01

    Cerebral microvascular disease predominantly affects brain white matter and deep grey matter, resulting in ischaemic damage that ranges from lacunar infarcts to white matter hyperintensities seen on magnetic resonance imaging. These lesions are common and result in both clinical stroke syndromes and accumulate over time, resulting in cognitive deficits and dementia. Magnetic resonance imaging studies suggest that these lesions progress over time, accumulate adjacent to prior lesions and have a penumbral region susceptible to further injury. The pathological correlates of this adjacent injury in surviving myelinated axons have not been previously defined. In this study, we sought to determine the molecular organization of axons in tissue adjacent to lacunar infarcts and in the regions surrounding microinfarcts, by determining critical elements in axonal function: the morphology and length of node of Ranvier segments and adjacent paranodal segments. We examined post-mortem brain tissue from six patients with lacunar infarcts and tissue from two patients with autosomal dominant retinal vasculopathy and cerebral leukoencephalopathy (previously known as hereditary endotheliopathy with retinopathy, nephropathy and stroke) who accumulate progressive white matter ischaemic lesions in the form of lacunar and microinfarcts. In axons adjacent to lacunar infarcts yet extending up to 150% of the infarct diameter away, both nodal and paranodal length increase by ∼20% and 80%, respectively, reflecting a loss of normal cell-cell adhesion and signalling between axons and oligodendrocytes. Using premorbid magnetic resonance images, brain regions from patients with retinal vasculopathy and cerebral leukoencephalopathy that harboured periventricular white matter hyperintensities were selected and the molecular organization of axons was determined within these regions. As in regions adjacent to lacunar infarcts, nodal and paranodal length in white matter of these patients is

  14. Nonlinear spin wave coupling in adjacent magnonic crystals

    NASA Astrophysics Data System (ADS)

    Sadovnikov, A. V.; Beginin, E. N.; Morozova, M. A.; Sharaevskii, Yu. P.; Grishin, S. V.; Sheshukova, S. E.; Nikitov, S. A.

    2016-07-01

    We have experimentally studied the coupling of spin waves in the adjacent magnonic crystals. Space- and time-resolved Brillouin light-scattering spectroscopy is used to demonstrate the frequency and intensity dependent spin-wave energy exchange between the side-coupled magnonic crystals. The experiments and the numerical simulation of spin wave propagation in the coupled periodic structures show that the nonlinear phase shift of spin wave in the adjacent magnonic crystals leads to the nonlinear switching regime at the frequencies near the forbidden magnonic gap. The proposed side-coupled magnonic crystals represent a significant advance towards the all-magnonic signal processing in the integrated magnonic circuits.

  15. Quad RF power meter

    SciTech Connect

    Stone, D.W.

    1987-09-01

    This report shows how to construct a four-channel RF power meter from circuit boards and components found in a Hewlett Packard Model 432A Power Meter. Included are descriptions of necessary modifications, electrical circuit diagrams, and a parts list. Each of the four power meters is compatible with a Hewlett Packard 432A Power Meter.

  16. Growth and decline of shoreline industry in Sydney estuary (Australia) and influence on adjacent estuarine sediments.

    PubMed

    Birch, G F; Lean, J; Gunns, T

    2015-06-01

    Sydney estuary (Australia), like many urbanised waterways, is degraded due to an extended history of anthropogenic activity. Two major sources of contamination to this estuary are discharge by former shoreline industries and historic and contemporary catchment stormwater. The objectives of the present study were to document changes in shoreline land use from European settlement to the present day and determine the influence of this trend on the metal content of adjacent estuarine sediments. Temporal analysis of land use for seven time horizons between 1788 and 2010 showed rapid expansion of industry along much of the Sydney estuary foreshore soon after European settlement due to the benefits of easy and inexpensive access and readily available water for cooling and power. Shoreline industry attained maximum development in 1978 (32-km length) and declined rapidly to the present-day (9-km length) through redevelopment of industrial sites into medium- to high-density, high-value residential housing. Cores taken adjacent to 11 long-term industrial sites showed that past industrial practices contributed significantly to contamination of estuarine sediment. Subsurface metal concentrations were up to 35 times that of present-day surface sediment and over 100 times greater than natural background concentrations. Sedimentation rates for areas adjacent to shoreline industry were between 0.6 and 2.5 cm/year, and relaxation times were estimated at 50 to 100 years. Natural relaxation and non-disturbance of sediments may be the best management practice in most locations.

  17. Denitrification in sediments from the hyporheic zone adjacent to a small forested stream

    USGS Publications Warehouse

    Duff, J.H.; Triska, F.J.

    1990-01-01

    Denitrifying potentials increased with increasing distance from the stream channel. Dissolved oxygen was 100% of the concentration expected in equilibrium with the atmosphere in water obtained from monitoring wells immediately adjacent to the stream but was as low as 7% of the expected value in water 11.4 m inland. Both nitrate and dissolved organic carbon decreased over summer in wells at the base of the alder-forested slope. A 48-h injection of nitrate-amended stream water into hyporheic water 8.4 m inland stimulated nitrous oxide production in the presence of acetylene. Nitrous oxide was generated as nitrate and acetylene were co-transported to a well 13 m down-gradient. Acetylene-block experiments coupled with the chemistry data suggest that denitrification can modify the chemistry of water during passage through the hyporheic zone. -from Authors

  18. Historic surface faulting in continental United States and adjacent parts of Mexico

    USGS Publications Warehouse

    Bonilla, M.G.

    1967-01-01

    This report summarizes geometric aspects of approximately 35 instances of historic faulting of the ground surface in the continental United States and adjacent parts of Mexico. This information is of immediate importance in the selection and evaluation of sites for vital structures such as nuclear power plants. The data are presented in a table and graphs which show the quantitative relations between various aspects of the faulting. Certain items in the table that are uncertain, poorly known, or not in the published literature are briefly described in the text.

  19. Agricultural intensification exacerbates spillover effects on soil biogeochemistry in adjacent forest remnants.

    PubMed

    Didham, Raphael K; Barker, Gary M; Bartlam, Scott; Deakin, Elizabeth L; Denmead, Lisa H; Fisk, Louise M; Peters, Jennifer M R; Tylianakis, Jason M; Wright, Hannah R; Schipper, Louis A

    2015-01-01

    Land-use intensification is a central element in proposed strategies to address global food security. One rationale for accepting the negative consequences of land-use intensification for farmland biodiversity is that it could 'spare' further expansion of agriculture into remaining natural habitats. However, in many regions of the world the only natural habitats that can be spared are fragments within landscapes dominated by agriculture. Therefore, land-sparing arguments hinge on land-use intensification having low spillover effects into adjacent protected areas, otherwise net conservation gains will diminish with increasing intensification. We test, for the first time, whether the degree of spillover from farmland into adjacent natural habitats scales in magnitude with increasing land-use intensity. We identified a continuous land-use intensity gradient across pastoral farming systems in New Zealand (based on 13 components of farmer input and soil biogeochemistry variables), and measured cumulative off-site spillover effects of fertilisers and livestock on soil biogeochemistry in 21 adjacent forest remnants. Ten of 11 measured soil properties differed significantly between remnants and intact-forest reference sites, for both fenced and unfenced remnants, at both edge and interior. For seven variables, the magnitude of effects scaled significantly with magnitude of surrounding land-use intensity, through complex interactions with fencing and edge effects. In particular, total C, total N, δ15N, total P and heavy-metal contaminants of phosphate fertilizers (Cd and U) increased significantly within remnants in response to increasing land-use intensity, and these effects were exacerbated in unfenced relative to fenced remnants. This suggests movement of livestock into surrounding natural habitats is a significant component of agricultural spillover, but pervasive changes in soil biogeochemistry still occur through nutrient spillover channels alone, even in fenced

  20. Agricultural Intensification Exacerbates Spillover Effects on Soil Biogeochemistry in Adjacent Forest Remnants

    PubMed Central

    Didham, Raphael K.; Barker, Gary M.; Bartlam, Scott; Deakin, Elizabeth L.; Denmead, Lisa H.; Fisk, Louise M.; Peters, Jennifer M. R.; Tylianakis, Jason M.; Wright, Hannah R.; Schipper, Louis A.

    2015-01-01

    Land-use intensification is a central element in proposed strategies to address global food security. One rationale for accepting the negative consequences of land-use intensification for farmland biodiversity is that it could ‘spare’ further expansion of agriculture into remaining natural habitats. However, in many regions of the world the only natural habitats that can be spared are fragments within landscapes dominated by agriculture. Therefore, land-sparing arguments hinge on land-use intensification having low spillover effects into adjacent protected areas, otherwise net conservation gains will diminish with increasing intensification. We test, for the first time, whether the degree of spillover from farmland into adjacent natural habitats scales in magnitude with increasing land-use intensity. We identified a continuous land-use intensity gradient across pastoral farming systems in New Zealand (based on 13 components of farmer input and soil biogeochemistry variables), and measured cumulative off-site spillover effects of fertilisers and livestock on soil biogeochemistry in 21 adjacent forest remnants. Ten of 11 measured soil properties differed significantly between remnants and intact-forest reference sites, for both fenced and unfenced remnants, at both edge and interior. For seven variables, the magnitude of effects scaled significantly with magnitude of surrounding land-use intensity, through complex interactions with fencing and edge effects. In particular, total C, total N, δ15N, total P and heavy-metal contaminants of phosphate fertilizers (Cd and U) increased significantly within remnants in response to increasing land-use intensity, and these effects were exacerbated in unfenced relative to fenced remnants. This suggests movement of livestock into surrounding natural habitats is a significant component of agricultural spillover, but pervasive changes in soil biogeochemistry still occur through nutrient spillover channels alone, even in fenced

  1. Solute uptake through the walls of a pulsating channel

    NASA Astrophysics Data System (ADS)

    Waters, S. L.

    2001-04-01

    We investigate the uptake of a passive solute through the walls of a pulsating, fluid-filled channel into an adjacent medium in which the solute diffuses and is consumed at a constant rate. One end of the channel is open to well-mixed fluid containing the solute. The channel walls oscillate periodically in time and this prescribed motion generates steady streaming within the channel. We determine how this flow enhances the overall solute consumption (i.e. the flux of solute into the channel), the solute dispersion along the channel and the quantity of solute in the adjacent medium. The solute disperses in the channel due to the interaction between advection and transverse diffusion. The time-mean solute distribution throughout the channel and the medium is determined for a wide range of parameters. The results are applied to a new surgical technique used to treat patients with severe coronary artery disease, in which narrow tubes are created within ischemic heart muscle in an attempt to reperfuse the area directly with oxygenated blood.

  2. Seepage from channeled flows as influenced by PAM and sediment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seepage from water streams into unlined channels determines the proportion of water distributed to adjacent soil for plant use or soil or groundwater recharge, or conveyed to downstream reaches. We conducted a laboratory study to determine how sediment type (none, clay, silt), sediment concentratio...

  3. Sediment and polyacrylamide effects on seepage losses from channeled flows

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seepage from water streams into unlined channels determines the proportion of water distributed to adjacent soil for plant use or soil or groundwater recharge, or conveyed to downstream reaches. We conducted a laboratory study to determine how inflow amendment and related factors, sediment type (no...

  4. 4. Elevation looking southwest from adjacent hills on northeast side ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. Elevation looking southwest from adjacent hills on northeast side of bridge, taken from river level. Note entire east side and substructure. - Presumpscot Falls Bridge, Spanning Presumptscot River at Allen Avenue extension, 0.75 mile west of U.S. Interstate 95, Falmouth, Cumberland County, ME

  5. 12. VIEW LOOKING WEST FROM THE PARKING LOT ADJACENT TO ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. VIEW LOOKING WEST FROM THE PARKING LOT ADJACENT TO THE STEEL PLANT OFFICES. BAR AND BILLET MILLS AND, IN THE DISTANCE, THE BASIC OXYGEN FURNACES MAY BE SEEN. - Corrigan, McKinney Steel Company, 3100 East Forty-fifth Street, Cleveland, Cuyahoga County, OH

  6. 8. Exterior view, showing tank and associated piping adjacent to ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Exterior view, showing tank and associated piping adjacent to Test Cell 6, Systems Integration Laboratory Building (T-28), looking south. - Air Force Plant PJKS, Systems Integration Laboratory, Systems Integration Laboratory Building, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

  7. 10. Detail and contextual view of bridge and adjacent farmstead ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. Detail and contextual view of bridge and adjacent farmstead setting. Note laced vertical compression members, latticed portal strut, decorative strut bracing, and lightness of diagonal and lateral tension members. View to southeast through southeast portal from truss mid-span. - Red Bank Creek Bridge, Spanning Red Bank Creek at Rawson Road, Red Bluff, Tehama County, CA

  8. 11. Interior detail, Boiler Room, fire door to the adjacent ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Interior detail, Boiler Room, fire door to the adjacent Blacksmith Shop, Roundhouse Machine Shop Extension, Southern Pacific Railroad Carlin Shops, view to southwest (90mm lens). - Southern Pacific Railroad, Carlin Shops, Roundhouse Machine Shop Extension, Foot of Sixth Street, Carlin, Elko County, NV

  9. 1. VIEW FROM SOUTHWEST SHOWING SOUTH (FRONT) ELEVATION, ADJACENT LOUGHRAN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. VIEW FROM SOUTHWEST SHOWING SOUTH (FRONT) ELEVATION, ADJACENT LOUGHRAN BUILDING (BASSIN'S RESTAURANT) (HABS No. DC-357), 501-511 14TH STREET (THE LOCKER ROOM) HABS No. DC-356) ON CORNER, AND MUNSEY BUILDING (HABS No. DC-358) - William J. Stone Building, 1345 E Street Northwest, Washington, District of Columbia, DC

  10. VIEW FROM ATOP ADJACENT RESIDENTIAL TOWER, SHOWING RECREATION AREA AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW FROM ATOP ADJACENT RESIDENTIAL TOWER, SHOWING RECREATION AREA AND ENTRY TO NEIGHBORHOOD. VIEW FACING SOUTHEAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  11. VIEW FROM ATOP ADJACENT RESIDENTIAL TOWER, SHOWING INTERSECTION OF ACACIA ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW FROM ATOP ADJACENT RESIDENTIAL TOWER, SHOWING INTERSECTION OF ACACIA ROAD WITH BIRCH CIRCLE. VIEW FACING NORTHEAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  12. VIEW FROM ATOP ADJACENT RESIDENTIAL TOWER, SHOWING RECREATION AREA ON ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW FROM ATOP ADJACENT RESIDENTIAL TOWER, SHOWING RECREATION AREA ON RIGHT, AND HOUSING AREA ON LEFT. VIEW FACING EAST/NORTHEAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  13. VIEW FROM ATOP ADJACENT RESIDENTIAL TOWER, SHOWING WESTERN SIDE OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW FROM ATOP ADJACENT RESIDENTIAL TOWER, SHOWING WESTERN SIDE OF NEIGHBORHOOD. VIEW FACING NORTHWEST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  14. 1. OVERVIEW SHOWING FIRING CONTROL BLOCKHOUSE 0502 AND ADJACENT OBSERVATION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. OVERVIEW SHOWING FIRING CONTROL BLOCKHOUSE 0502 AND ADJACENT OBSERVATION TOWER. WATER BRAKE TROUGH SEGMENT AT LOWER RIGHT. Looking north northeast. - Edwards Air Force Base, South Base Sled Track, Firing & Control Blockhouse for 10,000-foot Track, South of Sled Track at midpoint of 20,000-foot track, Lancaster, Los Angeles County, CA

  15. 22. Float located adjacent to entry stair in filtration bed. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    22. Float located adjacent to entry stair in filtration bed. The float actuates a valve that maintains water level over the bed. - Lake Whitney Water Filtration Plant, Filtration Plant, South side of Armory Street between Edgehill Road & Whitney Avenue, Hamden, New Haven County, CT

  16. 7. VIEW OF WATER TREATMENT PLANT, ADJACENT TO THE COAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. VIEW OF WATER TREATMENT PLANT, ADJACENT TO THE COAL CONVEYOR; IN THE DISTANCE IS THE FREQUENCY CHANGER HOUSE, WHICH IS ATTACHED TO SWITCH HOUSE NO. 1; LOOKING WEST. - Commonwealth Electric Company, Fisk Street Electrical Generating Station, 1111 West Cermak Avenue, Chicago, Cook County, IL

  17. 4. REAR ELEVATION, DETAIL OF CONSTRUCTION, ADJACENT CORNER POSTS BETWEEN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. REAR ELEVATION, DETAIL OF CONSTRUCTION, ADJACENT CORNER POSTS BETWEEN BUILDING PERIODS 1 AND 3. NOTE REUSED WOOD STRIP NAILED TO BUILDING PERIOD 1 POST INSCRIBED 'ST. LEONARD'. THERE ARE NO NAIL HOLES IN THE PERIOD 3 POST, THE FARRING STRIPS ADJUST FOR CLADDING - Charles' Gift, State Routes 2 & 4, Lusby, Calvert County, MD

  18. Biogeochemistry of hydrothermally and adjacent non-altered soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As a field/lab project, students in the Soil Biogeochemistry class of the University of Nevada, Reno described and characterized seven pedons, developed in hydrothermally and adjacent non-hydrothermally altered andesitic parent material near Reno, NV. Hydrothermally altered soils had considerably lo...

  19. 12. LOG FOUNDATION ELEMENTS OF THE SAWMILL ADJACENT TO THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. LOG FOUNDATION ELEMENTS OF THE SAWMILL ADJACENT TO THE CANAL, LOOKING EAST. BARREN AREA IN FOREGROUND IS DECOMPOSING SAWDUST. DIRT PILE IN BACKGROUND IS THE EDGE OF THE SUMMIT COUNTY LANDFILL. - Snake River Ditch, Headgate on north bank of Snake River, Dillon, Summit County, CO

  20. LEHR NO. 2 AND LEHR NO. 3 ADJACENT TO FURNACE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    LEHR NO. 2 AND LEHR NO. 3 ADJACENT TO FURNACE ROOM; THE PIPES AT THE BOTTOM ARE PART OF THE RADIANT HEATING SYSTEM USED FOR HEATING THE FACTORY DURING COLD WEATHER. - Westmoreland Glass Company, Seventh & Kier Streets, Grapeville, Westmoreland County, PA

  1. How subaerial salt extrusions influence water quality in adjacent aquifers

    NASA Astrophysics Data System (ADS)

    Mehdizadeh, Razieh; Zarei, Mehdi; Raeisi, Ezzat

    2015-12-01

    Brines supplied from salt extrusions cause significant groundwater salinization in arid and semi-arid regions where salt rock is exposed to dissolution by episodic rainfalls. Here we focus on 62 of the 122 diapirs of Hormuz salt emergent in the southern Iran. To consider managing the degradation effect that salt extrusions have on the quality of adjoining aquifers, it is first necessary to understand how they influence adjacent water resources. We evaluate here the impacts that these diapirs have on adjacent aquifers based on investigating their geomorphologies, geologies, hydrologies and hydrogeologies. The results indicate that 28/62 (45%) of our sample of salt diapirs have no significant impact on the quality of groundwater in adjoining aquifers (namely Type N), while the remaining 34/62 (55%) degrade nearby groundwater quality. We offer simple conceptual models that account for how brines flowing from each of these types of salt extrusions contaminate adjacent aquifers. We identify three main mechanisms that lead to contamination: surface impact (Type A), subsurface intrusion (Type B) and indirect infiltration (Type C). A combination of all these mechanisms degrades the water quality in nearby aquifers in 19/62 (31%) of the salt diapirs studied. Having characterized the mechanism(s) by which each diapir affects the adjacent aquifer, we suggest a few possible remediation strategies to be considered. For instance, engineering the surface runoff of diapirs Types A and C into nearby evaporation basins would improve groundwater quality.

  2. Wideband LTE power amplifier with integrated novel analog pre-distorter linearizer for mobile wireless communications.

    PubMed

    Uthirajoo, Eswaran; Ramiah, Harikrishnan; Kanesan, Jeevan; Reza, Ahmed Wasif

    2014-01-01

    For the first time, a new circuit to extend the linear operation bandwidth of a LTE (Long Term Evolution) power amplifier, while delivering a high efficiency is implemented in less than 1 mm2 chip area. The 950 µm × 900 µm monolithic microwave integrated circuit (MMIC) power amplifier (PA) is fabricated in a 2 µm InGaP/GaAs process. An on-chip analog pre-distorter (APD) is designed to improve the linearity of the PA, up to 20 MHz channel bandwidth. Intended for 1.95 GHz Band 1 LTE application, the PA satisfies adjacent channel leakage ratio (ACLR) and error vector magnitude (EVM) specifications for a wide LTE channel bandwidth of 20 MHz at a linear output power of 28 dBm with corresponding power added efficiency (PAE) of 52.3%. With a respective input and output return loss of 30 dB and 14 dB, the PA's power gain is measured to be 32.5 dB while exhibiting an unconditional stability characteristic from DC up to 5 GHz. The proposed APD technique serves to be a good solution to improve linearity of a PA without sacrificing other critical performance metrics.

  3. Wideband LTE Power Amplifier with Integrated Novel Analog Pre-Distorter Linearizer for Mobile Wireless Communications

    PubMed Central

    Uthirajoo, Eswaran; Ramiah, Harikrishnan; Kanesan, Jeevan; Reza, Ahmed Wasif

    2014-01-01

    For the first time, a new circuit to extend the linear operation bandwidth of a LTE (Long Term Evolution) power amplifier, while delivering a high efficiency is implemented in less than 1 mm2 chip area. The 950 µm × 900 µm monolithic microwave integrated circuit (MMIC) power amplifier (PA) is fabricated in a 2 µm InGaP/GaAs process. An on-chip analog pre-distorter (APD) is designed to improve the linearity of the PA, up to 20 MHz channel bandwidth. Intended for 1.95 GHz Band 1 LTE application, the PA satisfies adjacent channel leakage ratio (ACLR) and error vector magnitude (EVM) specifications for a wide LTE channel bandwidth of 20 MHz at a linear output power of 28 dBm with corresponding power added efficiency (PAE) of 52.3%. With a respective input and output return loss of 30 dB and 14 dB, the PA’s power gain is measured to be 32.5 dB while exhibiting an unconditional stability characteristic from DC up to 5 GHz. The proposed APD technique serves to be a good solution to improve linearity of a PA without sacrificing other critical performance metrics. PMID:25033049

  4. ECAP spread of excitation with virtual channels and physical electrodes.

    PubMed

    Hughes, Michelle L; Stille, Lisa J; Baudhuin, Jacquelyn L; Goehring, Jenny L

    2013-12-01

    The primary goal of this study was to evaluate physiological spatial excitation patterns for stimulation of adjacent physical electrodes and intermediate virtual channels. Two experiments were conducted that utilized electrically evoked compound action potential (ECAP) spread-of-excitation (SOE) functions obtained with the traditional forward-masking subtraction method. These two experiments examined spatial excitation patterns for virtual-channel maskers and probes, respectively. In Experiment 1, ECAP SOE patterns were obtained for maskers applied to physical electrodes and virtual channels to determine whether virtual-channel maskers yield SOE patterns similar to those predicted from physical electrodes. In Experiment 2, spatial separation of SOE functions was compared for two adjacent physical probe electrodes and the intermediate virtual channel to determine the extent to which ECAP SOE patterns for virtual-channel probes are spatially separate from those obtained with physical electrodes. Data were obtained for three electrode regions (basal, middle, apical) for 35 ears implanted with Cochlear (N = 16) or Advanced Bionics (N = 19) devices. Results from Experiment 1 showed no significant difference between predicted and measured ECAP amplitudes for Advanced Bionics subjects. Measured ECAP amplitudes for virtual-channel maskers were significantly larger than the predicted amplitudes for Cochlear subjects; however, the difference was <2 μV and thus is likely not clinically significant. Results from Experiment 2 showed that the probe set in the apical region demonstrated the least amount of spatial separation amongst SOE functions, which may be attributed to more uniform nerve survival patterns, closer electrode spacing, and/or the tapered geometry of the cochlea. As expected, adjacent physical probes demonstrated greater spatial separation than for comparisons between each physical probe and the intermediate virtual channel. Finally, the virtual-channel SOE

  5. TRPC channel activation by extracellular thioredoxin

    PubMed Central

    Xu, Shang-Zhong; Sukumar, Piruthivi; Zeng, Fanning; Li, Jing; Jairaman, Amit; English, Anne; Naylor, Jacqueline; Ciurtin, Coziana; Majeed, Yasser; Milligan, Carol J; Bahnasi, Yahya M; AL-Shawaf, Eman; Porter, Karen E; Jiang, Lin-Hua; Emery, Paul; Sivaprasadarao, Asipu; Beech, David J

    2009-01-01

    Mammalian homologues of Drosophila melanogaster transient receptor potential (TRP) are a large family of multimeric cation channels that act, or putatively act, as sensors of one or more chemical factor1,2. Major research objectives are the identification of endogenous activators and the determination of cellular and tissue functions of these novel channels. Here we show activation of TRPC5 homomultimeric and TRPC5-TRPC1 heteromultimeric channels3-5 by extracellular reduced thioredoxin acting by breaking a disulphide bridge in the predicted extracellular loop adjacent to the ion-selectivity filter of TRPC5. Thioredoxin is an endogenous redox protein with established intracellular functions, but it is also secreted and its extracellular targets are largely unknown6-9. Particularly high extracellular concentrations of thioredoxin are apparent in rheumatoid arthritis8,10-12, an inflammatory joint disease disabling millions of people world-wide13. We show that TRPC5 and TRPC1 are expressed in secretory fibroblast-like synoviocytes from patients with rheumatoid arthritis, endogenous TRPC5-TRPC1 channels of the cells are activated by reduced thioredoxin, and blockade of the channels enhances secretory activity and prevents suppression of secretion by thioredoxin. The data suggest a novel ion channel activation mechanism that couples extracellular thioredoxin to cell function. PMID:18172497

  6. Mutant Sodium Channel for Tumor Therapy

    PubMed Central

    Tannous, Bakhos A; Christensen, Adam P; Pike, Lisa; Wurdinger, Thomas; Perry, Katherine F; Saydam, Okay; Jacobs, Andreas H; García-Añoveros, Jaime; Weissleder, Ralph; Sena-Esteves, Miguel; Corey, David P; Breakefield, Xandra O

    2009-01-01

    Viral vectors have been used to deliver a wide range of therapeutic genes to tumors. In this study, a novel tumor therapy was achieved by the delivery of a mammalian brain sodium channel, ASIC2a, carrying a mutation that renders it constitutively open. This channel was delivered to tumor cells using a herpes simplex virus-1/Epstein–Barr virus (HSV/EBV) hybrid amplicon vector in which gene expression was controlled by a tetracycline regulatory system (tet-on) with silencer elements. Upon infection and doxycycline induction of mutant channel expression in tumor cells, the open channel led to amiloride-sensitive sodium influx as assessed by patch clamp recording and sodium imaging in culture. Within hours, tumor cells swelled and died. In addition to cells expressing the mutant channel, adjacent, noninfected cells connected by gap junctions also died. Intratumoral injection of HSV/EBV amplicon vector encoding the mutant sodium channel and systemic administration of doxycycline led to regression of subcutaneous tumors in nude mice as assessed by in vivo bioluminescence imaging. The advantage of this direct mode of tumor therapy is that all types of tumor cells become susceptible and death is rapid with no time for the tumor cells to become resistant. PMID:19259066

  7. One-dimensional pressure transfer models for acoustic-electric transmission channels

    NASA Astrophysics Data System (ADS)

    Wilt, K. R.; Lawry, T. J.; Scarton, H. A.; Saulnier, G. J.

    2015-09-01

    A method for modeling piezoelectric-based ultrasonic acoustic-electric power and data transmission channels is presented. These channels employ piezoelectric disk transducers to convey signals across a series of physical layers using ultrasonic waves. This model decomposes the mechanical pathway of the signal into individual ultrasonic propagation layers which are generally independent of the layer's adjacent domains. Each layer is represented by a two-by-two traveling pressure wave transfer matrix which relates the forward and reverse pressure waves on one side of the layer to the pressure waves on the opposite face, where each face is assumed to be in contact with a domain of arbitrary reference acoustic impedance. A rigorous implementation of ultrasonic beam spreading is introduced and implemented within applicable domains. Compatible pressure-wave models for piezoelectric transducers are given, which relate the electric voltage and current interface of the transducer to the pressure waves on one mechanical interface while also allowing for passive acoustic loading of the secondary mechanical interface. It is also shown that the piezoelectric model's electrical interface is compatible with transmission line parameters (ABCD-parameters), allowing for connection of electronic components and networks. The model is shown to be capable of reproducing the behavior of realistic physical channels.

  8. Propagation and deposition of stony debris flows at channel confluences

    NASA Astrophysics Data System (ADS)

    Stancanelli, L. M.; Lanzoni, S.; Foti, E.

    2015-07-01

    The fluid dynamics of stony debris flows generated in two small tributaries adjacent to each other and flowing into a main receiving channel was analyzed experimentally at a laboratory scale. The analysis on the propagation along the tributaries and deposition in the main channel provide information about sediment-water mobility, dangerous damming, and potential hazard. Debris flows were generated by releasing a preset water discharge over an erodible layer of saturated gravels material. As a consequence, the debris flow sediment concentration varied accordingly to the entrainment rate which, in turn, was strongly controlled by the tributary slope. The data collected by acoustic level sensors, pore fluid pressure transducers, and a load cell were used to characterize the evolution of bulk density and solid concentration of the sediment-water mixture. These two parameters were relevant to assess the stony debris flow mobility which contributes to determine the shape of sediment deposits in the main channel. The detailed bed topography surveys carried out in the main channel at the end of each experiment provided information on the morphology of these deposits and on the interplay of adjacent confluences. The influences of confluence angle, tributary slopes, and triggering conditions have been investigated, for a total of 18 different configurations. Within the investigated range of parameters, the slope angle was the parameter that mainly influences the stony debris flow mobility while, for adjacent confluences, the degree of obstruction within the receiving channel was strongly influenced by the triggering scenario.

  9. Ultrastructural observations reveal the presence of channels between cork cells.

    PubMed

    Teixeira, Rita Teresa; Pereira, Helena

    2009-12-01

    The ultrastructure of phellem cells of Quercus suber L. (cork oak) and Calotropis procera (Ait) R. Br. were analyzed using electron transmission microscopy to determine the presence or absence of plasmodesmata (PD). Different types of Q. suber cork samples were studied: one year shoots; virgin cork (first periderm), reproduction cork (traumatic periderm), and wet cork. The channel structures of PD were found in all the samples crossing adjacent cell walls through the suberin layer of the secondary wall. Calotropis phellem also showed PD crossing the cell walls of adjacent cells but in fewer numbers compared to Q. suber. In one year stems of cork oak, it was possible to follow the physiologically active PD with ribosomic accumulation next to the aperture of the channel seen in the phellogen cells to the completely obstructed channels in the dead cells that characterize the phellem tissue.

  10. Equalization in redundant channels

    NASA Technical Reports Server (NTRS)

    Tulpule, Bhalchandra R. (Inventor); Collins, Robert E. (Inventor); Cominelli, Donald F. (Inventor); O'Neill, Richard D. (Inventor)

    1988-01-01

    A miscomparison between a channel's configuration data base and a voted system configuration data base in a redundant channel system having identically operating, frame synchronous channels triggers autoequalization of the channel's historical signal data bases in a hierarchical, chronological manner with that of a correctly operating channel. After equalization, symmetrization of the channel's configuration data base with that of the system permits upgrading of the previously degraded channel to full redundancy. An externally provided equalization command, e.g., manually actuated, can also trigger equalization.

  11. New adjacent Bis-tetrahydrofuran Annonaceous acetogenins from Annona muricata.

    PubMed

    Chang, Fang-Rong; Liaw, Chih-Chuang; Lin, Chih-Yuan; Chou, Chi-Jung; Chiu, Hui-Fen; Wu, Yang-Chang

    2003-03-01

    Bioactivity-guided fractionation led to the isolation of two new Annonaceous acetogenins, annocatacin A ( 1). and annocatacin B ( 2). from the seeds and the leaves, respectively, of Annona muricata. Compounds 1 and 2 are the first examples where the adjacent bis-tetrahydrofuran ring system is located at C-15. The new structures were elucidated and characterized by spectral and chemical methods. Both Annonaceous acetogenins 1 and 2 showed significant in vitro cytotoxicity toward the human hepatoma cell lines, Hep G2 and 2,2,15, and were compared with the known adjacent bis-tetrahydrofuran acetogenins, neoannonin ( 3). desacetyluvaricin ( 4). bullatacin ( 5). asimicin ( 6). annoglaucin ( 7). squamocin ( 8). and rollimusin ( 9).

  12. A Micromechanical RF Channelizer

    NASA Astrophysics Data System (ADS)

    Akgul, Mehmet

    The power consumption of a radio generally goes as the number and strength of the RF signals it must process. In particular, a radio receiver would consume much less power if the signal presented to its electronics contained only the desired signal in a tiny percent bandwidth frequency channel, rather than the typical mix of signals containing unwanted energy outside the desired channel. Unfortunately, a lack of filters capable of selecting single channel bandwidths at RF forces the front-ends of contemporary receivers to accept unwanted signals, and thus, to operate with sub-optimal efficiency. This dissertation focuses on the degree to which capacitive-gap transduced micromechanical resonators can achieve the aforementioned RF channel-selecting filters. It aims to first show theoretically that with appropriate scaling capacitive-gap transducers are strong enough to meet the needed coupling requirements; and second, to fully detail an architecture and design procedure needed to realize said filters. Finally, this dissertation provides an actual experimentally demonstrated RF channel-select filter designed using the developed procedures and confirming theoretical predictions. Specifically, this dissertation introduces four methods that make possible the design and fabrication of RF channel-select filters. The first of these introduces a small-signal equivalent circuit for parallel-plate capacitive-gap transduced micromechanical resonators that employs negative capacitance to model the dependence of resonance frequency on electrical stiffness in a way that facilitates the analysis of micromechanical circuits loaded with arbitrary electrical impedances. The new circuit model not only correctly predicts the dependence of electrical stiffness on the impedances loading the input and output electrodes of parallel-plate capacitive-gap transduced micromechanical device, but does so in a visually intuitive way that identifies current drive as most appropriate for

  13. 20. Interior view of fuel storage pit or vault adjacent ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. Interior view of fuel storage pit or vault adjacent to Test Cell 9 in Component Test Laboratory (T-27), looking west. Photograph shows upgraded instrumentation, piping, tanks, and technological modifications installed in 1997-99 to accommodate component testing requirements for the Atlas V missile. - Air Force Plant PJKS, Systems Integration Laboratory, Components Test Laboratory, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

  14. Osmium complex binding to mismatched methylcytosine: effect of adjacent bases.

    PubMed

    Nomura, Akiko; Tainaka, Kazuki; Okamoto, Akimitsu

    2009-01-01

    We investigated the efficiency of osmium complex formation at 5-methylcytosine in mismatched DNA duplexes. Osmium complexation was not observed in fully matched duplexes, whereas the complexation site and efficiency in mismatched duplexes depended on the 5'-neighboring base of the 5-methylcytosine. In particular, when the base adjacent to the 5' side of the mismatched base pair was thymine, a unique side reaction was observed. However, the mismatched base pairs did not influence the selectivity of osmium complexation with methylated DNA.

  15. Jaw position uncertainty and adjacent fields in breast cancer radiotherapy.

    PubMed

    Hedin, Emma; Bäck, Anna; Chakarova, Roumiana

    2015-11-08

    Locoregional treatment of breast cancer involves adjacent, half blocked fields matched at isocenter. The objective of this work is to study the dosimetric effects of the uncertainties in jaw positioning for such a case, and how a treatment planning protocol including adjacent field overlap of 1 mm affects the dose distribution. A representative treatment plan, involving 6 and 15 photon beams, for a patient treated at our hospital is chosen. Monte Carlo method (EGSnrc/BEAMnrc) is used to simulate the treatment. Uncertainties in jaw positioning of ± 1 mm are addressed, which implies extremes in reality of 2 mm field gap/overlap when planning adjacent fields without overlap and 1 mm gap or 3 mm overlap for a planning protocol with 1 mm overlap. Dosimetric parameters for PTV, lung and body are analyzed. Treatment planning protocol with 1 mm overlap of the adjacent fields does not considerably counteract possible underdosage of the target in the case studied. PTV-V95% is for example reduced from 95% for perfectly aligned fields to 90% and 91% for 2 mm and 1 mm gap, respectively. However, the risk of overdosage in PTV and in healthy soft tissue is increased when following the protocol with 1 mm overlap. A 3 mm overlap compared to 2 mm overlap results in an increase in maximum dose to PTV, PTV-D2%, from 113% to 121%. V120% for 'Body-PTV' is also increased from 5 cm(3) to 14 cm(3). A treatment planning protocol with 1 mm overlap does not considerably improve the coverage of PTV in the case of erroneous jaw positions causing gap between fields, but increases the overdosage in PTV and doses to healthy tissue, in the case of overlapping fields, for the case investigated.

  16. Conference room 211, adjacent to commander's quarters, with vault door ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Conference room 211, adjacent to commander's quarters, with vault door at right. Projection area at center is equipped with automatic security drapes. Projection room uses a 45 degree mirror to reflect the image onto the frosted glass screen. Door on far left leads to display area senior battle staff viewing bridge, and the commander's quarters - March Air Force Base, Strategic Air Command, Combat Operations Center, 5220 Riverside Drive, Moreno Valley, Riverside County, CA

  17. Mutual Diffusional Interference Between Adjacent Stomata of a Leaf 1

    PubMed Central

    Cook, G. D.; Viskanta, R.

    1968-01-01

    The mutual diffusional interference between adjacent stomata in laminar flow over a leaf is shown to play a decisive role in determining overall transpiration. The magnitude of this interference varies with the interaction of the vapor diffusional shells forming above each stoma and the air flow over the leaf. The interference decreases with increasing incident radiation and wind velocity. The effect of interference on the stomatal resistance to diffusion plays a major role in the overall variations in transpiration. PMID:16656876

  18. Divergent viral presentation among human tumors and adjacent normal tissues

    PubMed Central

    Cao, Song; Wendl, Michael C.; Wyczalkowski, Matthew A.; Wylie, Kristine; Ye, Kai; Jayasinghe, Reyka; Xie, Mingchao; Wu, Song; Niu, Beifang; Grubb, Robert; Johnson, Kimberly J.; Gay, Hiram; Chen, Ken; Rader, Janet S.; Dipersio, John F.; Chen, Feng; Ding, Li

    2016-01-01

    We applied a newly developed bioinformatics system called VirusScan to investigate the viral basis of 6,813 human tumors and 559 adjacent normal samples across 23 cancer types and identified 505 virus positive samples with distinctive, organ system- and cancer type-specific distributions. We found that herpes viruses (e.g., subtypes HHV4, HHV5, and HHV6) that are highly prevalent across cancers of the digestive tract showed significantly higher abundances in tumor versus adjacent normal samples, supporting their association with these cancers. We also found three HPV16-positive samples in brain lower grade glioma (LGG). Further, recurrent HBV integration at the KMT2B locus is present in three liver tumors, but absent in their matched adjacent normal samples, indicating that viral integration induced host driver genetic alterations are required on top of viral oncogene expression for initiation and progression of liver hepatocellular carcinoma. Notably, viral integrations were found in many genes, including novel recurrent HPV integrations at PTPN13 in cervical cancer. Finally, we observed a set of HHV4 and HBV variants strongly associated with ethnic groups, likely due to viral sequence evolution under environmental influences. These findings provide important new insights into viral roles of tumor initiation and progression and potential new therapeutic targets. PMID:27339696

  19. Channel nut tool

    DOEpatents

    Olson, Marvin

    2016-01-12

    A method, system, and apparatus for installing channel nuts includes a shank, a handle formed on a first end of a shank, and an end piece with a threaded shaft configured to receive a channel nut formed on the second end of the shaft. The tool can be used to insert or remove a channel nut in a channel framing system and then removed from the channel nut.

  20. 18 CFR 1304.303 - Channel excavation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... within the flood control zone of a TVA reservoir requires TVA review and approval. (c) TVA shall... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Channel excavation. 1304.303 Section 1304.303 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY...

  1. 18 CFR 1304.303 - Channel excavation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... within the flood control zone of a TVA reservoir requires TVA review and approval. (c) TVA shall... 18 Conservation of Power and Water Resources 2 2011-04-01 2011-04-01 false Channel excavation. 1304.303 Section 1304.303 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY...

  2. Human-induced stream channel abandonment/capture and filling of floodplain channels within the Atchafalaya River Basin, Louisiana

    USGS Publications Warehouse

    Kroes, Daniel E.; Kraemer, Thomas F.

    2013-01-01

    The Atchafalaya River Basin is a distributary system of the Mississippi River containing the largest riparian area in the lower Mississippi River Valley and the largest remaining forested bottomland in North America. Reductions in the area of open water in the Atchafalaya have been occurring over the last 100 years, and many historical waterways are increasingly filled by sediment. This study examines two cases of swamp channels (3/s) that are filling and becoming unnavigable as a result of high sediment loads and slow water velocities. The water velocities in natural bayous are further reduced because of flow capture by channels constructed for access. Bathymetry, flow, suspended sediment, deposited bottom-material, isotopes, and photointerpretation were used to characterize the channel fill. On average, water flowing through these two channels lost 23% of the suspended sediment load in the studied reaches. Along one of the studied reaches, two constructed access channels diverted significant flow out of the primary channel and into the adjacent swamp. Immediately downstream of each of the two access channels, the cross-sectional area of the studied channel was reduced. Isotopic analyses of bottom-material cores indicate that bed filling has been rapid and occurred after detectable levels of Cesium-137 were no longer being deposited. Interpretation of aerial photography indicates that water is bypassing the primary channels in favor of the more hydraulically efficient access channels, resulting in low or no-velocity flow conditions in the primary channel. These swamp channel conditions are typical in the Atchafalaya River Basin where relict large channel dimensions result in flow velocities that are normally too low to carry fine-grained sediment. Constructed channels increase the rate of natural channel avulsion and abandonment as a result of flow capture.

  3. Interactions Between Hillslope Processes and Channel Form in a Logged Coastal Redwood Forest

    NASA Astrophysics Data System (ADS)

    Lisle, T. E.; Reid, L. M.; Hilton, S.

    2009-12-01

    Impacts of land-use activities can appear far downstream of the activity sites, introducing potentials for downstream impact accumulation and for lengthy time-lags between activity and impact. Consequently, attribution of particular downstream changes to specific upstream activities is often difficult. We conducted a series of hydrologic and geomorphic studies to evaluate pathways of influence between changes occurring on hillslopes and downstream channel responses at the Caspar Creek Experimental Watersheds in northwest California. About 39% of the second-growth redwood forest in the 473-ha North Fork Caspar Creek watershed was clearcut between 1989 and 1991. Stream gauges at the mouths of five logged subwatersheds showed increased average peakflow, runoff, and suspended sediment yield relative to three control watersheds. Modeling on the basis of rainfall interception measurements suggests that about 2/3 of the change in peakflow magnitudes results from altered interception after logging and 1/3 from reduced transpiration. Field surveys of erosion process distribution—including landslides, surface erosion, bank erosion, and gully erosion—suggest that in-channel erosion processes provided the dominant influence on sediment increases in the three years following logging. Changes in sediment load are most strongly correlated with runoff changes, but sediment increases at the mouth of the watershed are lower than predicted from sub-watershed outputs, suggesting deposition has occurred along the mainstem. Comparison of channel characteristics in logged and control watersheds indicates that networks expanded headward in the logged watersheds to a point that stream-power indices reflecting the altered hydrology are equivalent to those at channel heads before logging. In addition, channels are wider and deeper in reaches draining logged watersheds. Cross sections are resurveyed and woody debris tagged and remapped at approximately 2-year intervals along the North

  4. 1. CONTEXTUAL VIEW OF THE NORTH CHANNEL DAM FROM PUBLICLY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. CONTEXTUAL VIEW OF THE NORTH CHANNEL DAM FROM PUBLICLY RESTRICTED PROPERTY OF THE RECENTLY CLOSED LOUISIANA PACIFIC LUMBER MILL. THE NORTH CHANNEL DAM'S HOLDING RESERVOIR AND TAINTER GATES ARE IN THE FOREGROUND, AND THE ROLLING SECTOR GATE IS IN THE BACKGROUND, LOOKING EAST. - Washington Water Power Company Post Falls Power Plant, North Channel Dam, West of intersection of Spokane & Fourth Streets, Post Falls, Kootenai County, ID

  5. Microfluidic channel fabrication method

    DOEpatents

    Arnold, Don W.; Schoeniger, Joseph S.; Cardinale, Gregory F.

    2001-01-01

    A new channel structure for microfluidic systems and process for fabricating this structure. In contrast to the conventional practice of fabricating fluid channels as trenches or grooves in a substrate, fluid channels are fabricated as thin walled raised structures on a substrate. Microfluidic devices produced in accordance with the invention are a hybrid assembly generally consisting of three layers: 1) a substrate that can or cannot be an electrical insulator; 2) a middle layer, that is an electrically conducting material and preferably silicon, forms the channel walls whose height defines the channel height, joined to and extending from the substrate; and 3) a top layer, joined to the top of the channels, that forms a cover for the channels. The channels can be defined by photolithographic techniques and are produced by etching away the material around the channel walls.

  6. Gramicidin Channels: Versatile Tools

    NASA Astrophysics Data System (ADS)

    Andersen, Olaf S.; Koeppe, Roger E., II; Roux, Benoît

    Gramicidin channels are miniproteins in which two tryptophan-rich subunits associate by means of transbilayer dimerization to form the conducting channels. That is, in contrast to other ion channels, gramicidin channels do not open and close; they appear and disappear. Each subunit in the bilayer-spanning channel is tied to the bilayer/solution interface through hydrogen bonds that involve the indole NH groups as donors andwater or the phospholipid backbone as acceptors. The channel's permeability characteristics are well-defined: gramicidin channels are selective for monovalent cations, with no measurable permeability to anions or polyvalent cations; ions and water move through a pore whose wall is formed by the peptide backbone; and the single-channel conductance and cation selectivity vary when the amino acid sequence is varied, even though the permeating ions make no contact with the amino acid side chains. Given the plethora of available experimental information—for not only the wild-type channels but also for channels formed by amino acid-substituted gramicidin analogues—gramicidin channels continue to provide important insights into the microphysics of ion permeation through bilayer-spanning channels. For similar reasons, gramicidin channels constitute a system of choice for evaluating computational strategies for obtaining mechanistic insights into ion permeation through the more complex channels formed by integral membrane proteins.

  7. Channel Incision and Water-Table Decline Along a Recently Formed Proglacial Stream, Mendenhall Valley, Southeastern Alaska

    USGS Publications Warehouse

    Neal, Edward G.

    2009-01-01

    Retreat of the Mendenhall Glacier, in southeastern Alaska, resulted in the formation of Mendenhall Lake, which has reduced the supply of coarse sediment to the proglacial Mendenhall River. Channel geometry surveys conducted in 1969 and 1998 over a 5.3 km reach of the Mendenhall River revealed reductions in mean bed elevations ranging from 0.4 to 1.5 meters based on cross sections replicated at 7 locations. Channel incision in the Mendenhall River is believed to be the result of a combination of factors resulting from localized and region-wide glacial retreat. In addition to a reduction of river stage due to channel incision, a decline in water-table elevations of about 0.6 m during a 17-year period from 1984 to 2001 was identified in an observation well located 250 m from the incising stream channel. Water-table elevations 600 m from the incising channel in the adjacent alluvial outwash aquifer respond in phase to changes in river stage, indicating water-levels in the adjacent aquifer are declining in response to river-channel incision. This study suggests channel incision can rapidly lower water-table elevations for large distances in the adjacent aquifer, potentially modifying the hydrology to a degree capable of influencing adjacent surface-water features, such as off-channel wetlands and flood-plain side channels.

  8. Enhanced Phase Synchronization of Blood Flow Oscillations between Heated and Adjacent Non-heated Sacral Skin

    PubMed Central

    Liao, Fuyuan; Jan, Yih-Kuen

    2012-01-01

    The study of skin microcirculation may be used to assess risk for pressure ulcers. It is observed that local heating not only causes an increase in blood flow of the heated skin but also in the adjacent non-heated skin. The underlying physiological mechanism of this indirect vasodilation of the non-heated skin remains unclear. We hypothesized that blood flow oscillations (BFO) in the adjacent non-heated skin area synchronize with BFO in the heated skin, thus inducing a vasodilatory response. We investigated BFO in the heated and adjacent non-heated skin (12.1±1.2 cm distance) on the sacrum in 12 healthy participants. The ensemble empirical mode decomposition (EEMD) was used to decompose blood flow signals into a set of intrinsic mode functions (IMFs), and the IMFs with power spectra over the frequency range of 0.0095–0.02 Hz, 0.02–0.05 Hz, and 0.05–0.15 Hz were chosen as the characteristic components corresponding to metabolic, neurogenic, and myogenic regulations, respectively. Then, the instantaneous phase of the characteristic components was calculated using the Hilbert transform. From the time series of phase difference between a pair of characteristic components, the epochs of phase synchronization were detected. The results showed that myogenic and neurogenic BFO exhibit self-phase synchronization during the slower vasodilation of the heated skin. In the non-heated skin, the degree of synchronization of BFO is associated with the changes in blood flow. PMID:22936012

  9. Alteration-weakening leading to localized deformation in a damage aureole adjacent to a dormant shear zone

    NASA Astrophysics Data System (ADS)

    Backeberg, Nils R.; Rowe, Christie D.; Barshi, Naomi

    2016-09-01

    Deformation adjacent to faults and shear zones is traditionally thought to correlate with slip. Inherited structures may control damage geometry, localizing fluid flow and deformation in a damage aureole around structures, even after displacement has ceased. In this paper we document a post-shearing anastomosing foliation and fracture network that developed to one side of the Mesoarchean Marmion Shear Zone. This fracture network hosts the low-grade, disseminated Hammond Reef gold deposit. The shear zone juxtaposed a greenstone belt against tonalite gneiss and was locked by an intrusion that was emplaced during the final stages of suturing. After cessation of activity, fluids channeled along fault- and intrusion-related fractures led to the pervasive sericitization of feldspars. Foliated zones resulted from flattening in the weaker sericite-rich tonalite during progressive alteration without any change in the regional NW-SE shortening direction. The anastomosing pattern may have been inherited from an earlier ductile fabric, but sericite alteration and flattening fabrics all formed post-shearing. Thus, the apparent foliated fracture network adjacent to the Marmion Shear Zone is a second-order effect of shear-related damage, distinct in time from shear activity, adjacent to an effectively dormant shear zone. This phenomenon has implications for understanding the relative timing of fault zone activity, alteration and (in this case) gold mineralization related to long-term fault zone permeability.

  10. Design of a communications system for multiple telemetry data channels operating simultaneously with a coherent turn-around ranging channel

    NASA Technical Reports Server (NTRS)

    Nguyen, Tien M.; Hinedi, Sami M.; Gevargiz, John M.

    1991-01-01

    This paper presents a simple technique to design a phase-modulated residual carrier communications link for optimum performance. The emphasis is on two data channels which are operated simultaneously with a ranging signal. The data channels employ PCM/PM and PCM/PSK/PM modulation schemes for high and low data rate channels, respectively. The technique proposed here selects the optimum (1) subcarrier frequency to minimize the interference between the two data channels, and (2) modulation indices for optimum balance of power between the two telemetry data channels and the coherent turn around ranging channel. The selected set of optimum modulation indices will allow for the specified bit error rate (BER) degradations in the two data channels. Although this technique is proposed to optimize the performance degradation for two data channels, generalizations can be made for more than two data channels.

  11. Cholesterol and Ion Channels

    PubMed Central

    Levitan, Irena; Fang, Yun; Rosenhouse-Dantsker, Avia; Romanenko, Victor

    2010-01-01

    A variety of ion channels, including members of all major ion channel families, have been shown to be regulated by changes in the level of membrane cholesterol and partition into cholesterol-rich membrane domains. In general, several types of cholesterol effects have been described. The most common effect is suppression of channel activity by an increase in membrane cholesterol, an effect that was described for several types of inwardly-rectifying K+ channels, voltage-gated K+ channels, Ca+2 sensitive K+ channels, voltage-gated Na+ channels, N-type voltage-gated Ca+2 channels and volume-regulated anion channels. In contrast, several types of ion channels, such as epithelial amiloride-sensitive Na+ channels and Transient Receptor Potential channels, as well as some of the types of inwardly-rectifying and voltage-gated K+ channels were shown to be inhibited by cholesterol depletion. Cholesterol was also shown to alter the kinetic properties and current-voltage dependence of several voltage-gated channels. Finally, maintaining membrane cholesterol level is required for coupling ion channels to signalling cascades. In terms of the mechanisms, three general mechanisms have been proposed: (i) specific interactions between cholesterol and the channel protein, (ii) changes in the physical properties of the membrane bilayer and (iii) maintaining the scaffolds for protein-protein interactions. The goal of this review is to describe systematically the role of cholesterol in regulation of the major types of ion channels and to discuss these effects in the context of the models proposed. PMID:20213557

  12. Fading channel simulator

    SciTech Connect

    Argo, P.E.; Fitzgerald, T.J.

    1991-12-31

    This invention relates to high frequency (HF) radio signal propagation through fading channels and, more particularly, to simulation of fading channels in order to characterize HF radio system performance in transmitting and receiving signals through such fading channels. Fading channel effects on a transmitted communication signal are simulated with both frequency and time variations using a channel scattering function to affect the transmitted signal. A conventional channel scattering function is converted to a series of channel realizations by multiplying the square root of the channel scattering function by a complex number of which the real and imaginary parts are each independent variables. The two-dimensional inverse-FFT of this complex-valued channel realization yields a matrix of channel coefficients that provide a complete frequency-time description of the channel. The transmitted radio signal is segmented to provide a series of transmitted signal and each segment is subject to FFT to generate a series of signal coefficient matrices. The channel coefficient matrices and signal coefficient matrices are then multiplied and subjected to inverse-FFT to output a signal representing the received affected radio signal. A variety of channel scattering functions can be used to characterize the response of a transmitter-receiver system to such atmospheric effects.

  13. Ambiguities in the elastic scattering of 8 MeV neutrons from adjacent nuclei

    SciTech Connect

    Smith, A.B.; Lawson, R.D.; Guenther, P.T.

    1989-10-01

    Ratios of the cross sections for elastic scattering of 8 MeV neutrons from adjacent nuclei are measured over the angular range {approx}20{degree} {minus} 160{degree} for the target pairs {sup 51}V/Cr, {sup 59}Co/{sup 58}Ni, Cu/Zn, {sup 89}Y/{sup 93}Nb, {sup 89}Y/Zr, {sup 93}Nb/Zr, In/Cd and {sup 209}Bi/Pb. The observed ratios vary from unity by as much as a factor of {approx}2 at some angles for the lighter target pairs. Approximately half the measured ratios are reasonably explained by a simple spherical optical model, including size and isospin contributions. In all cases, the geometry of the real optical--model potential is essentially the same for neighboring nuclei, and the real--potential strengths are consistent with the Lane model. In contrast, it is found that the imaginary potential may be quite different for adjacent nuclei, and the nature of this difference is examined. It is shown that the spin--spin interaction has a negligible effect on the calculation of the elastic--scattering ratios, but that channel coupling, leading to a large reorientation of the target ground state, can be a consideration, particularly in the {sup 59}Co/{sup 58}Ni case. In the A {approx} 50--60 region the calculated ratios are sensitive to spin--orbit effects, but the exact nature of this interaction must await more definitive polarization measurements. The measured and calculated results suggest that the concept of a conventional global'' or even regional'' optical potential provides no more than a qualitative representation of the physical reality for a number of cases. 48 refs., 14 figs., 3 tabs.

  14. Synthesis of a Molecule with Four Different Adjacent Pnictogens.

    PubMed

    Hinz, Alexander; Schulz, Axel; Villinger, Alexander

    2016-08-22

    The synthesis of a molecule containing four adjacent different pnictogens was attempted by conversion of a Group 15 allyl analogue anion [Mes*NAsPMes*](-) (Mes*=2,4,6-tri-tert-butylphenyl) with antimony(III) chloride. A suitable precursor is Mes*N(H)AsPMes* (1) for which several syntheses were investigated. The anions afforded by deprotonation of Mes*N(H)AsPMes* were found to be labile and, therefore, salts could not be isolated. However, the in situ generated anions could be quenched with SbCl3 , yielding Mes*N(SbCl2 )AsPMes* (4). PMID:27377437

  15. CLOUD PEAK PRIMITIVE AREA AND ADJACENT AREAS, WYOMING.

    USGS Publications Warehouse

    Kiilsgaard, Thor H.; Patten, Lowell L.

    1984-01-01

    The results of a mineral survey of the Cloud Peak Primitive Area and adjacent areas in Wyoming indicated little promise for the occurrence of mineral resources. There are some prospect workings, particularly in the northern part of the area, but in none of them were there indications that ore had been mined. Samples from the workings, from nearby rocks and sediments from streams that drain the area did not yield any metal values of significance. The crystalline rocks that underlie the area do not contain oil and gas or coal, products that are extracted from the younger rocks that underlie basins on both sides of the study area.

  16. Interaction of Cracks Between Two Adjacent Indents in Glass

    NASA Technical Reports Server (NTRS)

    Choi, S. R.; Salem, J. A.

    1993-01-01

    Experimental observations of the interaction behavior of cracks between two adjacent indents were made using an indentation technique in soda-lime glass. It was specifically demonstrated how one indent crack initiates and propagates in the vicinity of another indent crack. Several types of crack interactions were examined by changing the orientation and distance of one indent relative to the other. It was found that the residual stress field produced by elastic/plastic indentation has a significant influence on controlling the mode of crack interaction. The interaction of an indent crack with a free surface was also investigated for glass and ceramic specimens.

  17. Retroperitoneal multilocular bronchogenic cyst adjacent to adrenal gland.

    PubMed

    Yang, S W; Linton, J A; Ryu, S J; Shin, D H; Park, C S

    1999-10-01

    Bronchogenic cysts are generally found in the mediastinum, particularly posterior to the carina, but they rarely occur in such unusual sites as the skin, subcutaneous tissue, pericardium, and even the retroperitoneum. A 30-year-old Korean man underwent surgery to remove a cystic adrenal mass incidentally discovered during routine physical checkup. At surgery, it proved to be a multilocular cyst located in the retroperitoneum adjacent to the left adrenal gland. Microscopically, the cyst was lined by respiratory epithelium over connective tissue with submucous glands, cartilage and smooth muscle, thereby histologically confirming bronchogenic cyst. This is the first reported case of retroperitoneal bronchogenic cyst in an adult without other congenital anomalies in Korea.

  18. Herbal Compounds and Toxins Modulating TRP Channels

    PubMed Central

    Vriens, Joris; Nilius, Bernd; Vennekens, Rudi

    2008-01-01

    Although the benefits are sometimes obvious, traditional or herbal medicine is regarded with skepticism, because the mechanism through which plant compounds exert their powers are largely elusive. Recent studies have shown however that many of these plant compounds interact with specific ion channels and thereby modulate the sensing mechanism of the human body. Especially members of the Transient Receptor Potential (TRP) channels have drawn large attention lately as the receptors for plant-derived compounds such as capsaicin and menthol. TRP channels constitute a large and diverse family of channel proteins that can serve as versatile sensors that allow individual cells and entire organisms to detect changes in their environment. For this family, a striking number of empirical views have turned into mechanism-based actions of natural compounds. In this review we will give an overview of herbal compounds and toxins, which modulate TRP channels. PMID:19305789

  19. Trends in Developed Land Cover Adjacent to Habitat for Threatened Salmon in Puget Sound, Washington, U.S.A.

    PubMed Central

    Bartz, Krista K.; Ford, Michael J.; Beechie, Timothy J.; Fresh, Kurt L.; Pess, George R.; Kennedy, Robert E.; Rowse, Melinda L.; Sheer, Mindi

    2015-01-01

    For widely distributed species at risk, such as Pacific salmon (Oncorhynchus spp.), habitat monitoring is both essential and challenging. Only recently have widespread monitoring programs been implemented for salmon habitat in the Pacific Northwest. Remote sensing data, such as Landsat images, are therefore a useful way to evaluate trends prior to the advent of species-specific habitat monitoring programs. We used annual (1986-2008) land cover maps created from Landsat images via automated algorithms (LandTrendr) to evaluate trends in developed (50-100% impervious) land cover in areas adjacent to five types of habitat utilized by Chinook salmon (O. tshawytscha) in the Puget Sound region of Washington State, U.S.A. For the region as a whole, we found significant increases in developed land cover adjacent to each of the habitat types evaluated (nearshore, estuary, mainstem channel, tributary channel, and floodplain), but the increases were small (<1% total increase from 1986 to 2008). For each habitat type, the increasing trend changed during the time series. In nearshore, mainstem, and floodplain areas, the rate of increase in developed land cover slowed in the latter portion of the time series, while the opposite occurred in estuary and tributary areas. Watersheds that were already highly developed in 1986 tended to have higher rates of development than initially less developed watersheds. Overall, our results suggest that developed land cover in areas adjacent to Puget Sound salmon habitat has increased only slightly since 1986 and that the rate of change has slowed near some key habitat types, although this has occurred within the context of a degraded baseline condition. PMID:25923327

  20. Stress Wave Interaction Between Two Adjacent Blast Holes

    NASA Astrophysics Data System (ADS)

    Yi, Changping; Johansson, Daniel; Nyberg, Ulf; Beyglou, Ali

    2016-05-01

    Rock fragmentation by blasting is determined by the level and state of stress in the rock mass subjected to blasting. With the application of electronic detonators, some researchers stated that it is possible to achieve improved fragmentation through stress wave superposition with very short delay times. This hypothesis was studied through theoretical analysis in the paper. First, the stress in rock mass induced by a single-hole shot was analyzed with the assumptions of infinite velocity of detonation and infinite charge length. Based on the stress analysis of a single-hole shot, the stress history and tensile stress distribution between two adjacent holes were presented for cases of simultaneous initiation and 1 ms delayed initiation via stress superposition. The results indicated that the stress wave interaction is local around the collision point. Then, the tensile stress distribution at the extended line of two adjacent blast holes was analyzed for a case of 2 ms delay. The analytical results showed that the tensile stress on the extended line increases due to the stress wave superposition under the assumption that the influence of neighboring blast hole on the stress wave propagation can be neglected. However, the numerical results indicated that this assumption is unreasonable and yields contrary results. The feasibility of improving fragmentation via stress wave interaction with precise initiation was also discussed. The analysis in this paper does not support that the interaction of stress waves improves the fragmentation.

  1. Adjacent flaps for lower lip reconstruction after mucocele resection.

    PubMed

    Ying, Binbin

    2012-03-01

    Mucocele forms because of salivary gland mucous extravasation or retention and is usually related to trauma in the area of the lower lip. It is a common benign lesion in the oral region. Although there are many conservative treatments such as the creation of a pouch (marsupialization), freezing (cryosurgery), micromarsupialization, and CO2 laser vaporization, surgical resection is the most commonly used means. Generally speaking, an elliptic incision was made to fully enucleate the lesion along with the overlying mucosa and the affected glands, then direct suturing is adequate. However, in some cases, direct suturing could cause lower lip deformity, and adjacent flaps for lower lip reconstruction after mucocele resection might be quite necessary. Based on our experience, adjacent mucosal flaps could be used when lesions were close to or even break through the vermilion border or their diameters were much more than 1 cm. A-T advancement flaps and transposition flaps were the mostly applied ones. Follow-up showed that all patients realized primary healing after 1 week postoperatively with satisfactory lower lip appearance, and there was no sign of increasing incidence of relapse. PMID:22421867

  2. Bacterial community structure in the Sulu Sea and adjacent areas

    NASA Astrophysics Data System (ADS)

    Yoshida, Akihiro; Nishimura, Masahiko; Kogure, Kazuhiro

    2007-01-01

    The deep waters of the Sulu Sea are characterized by relatively high and constant water temperatures and low oxygen concentrations. To examine the effect of these characteristics on the bacterial community structure, the culture-independent molecular method was applied to samples from the Sulu Sea and the adjacent areas. DNA was extracted from environmental samples, and the analysis was carried out on PCR-amplified 16S rDNA; fragments were analyzed by denaturing gradient gel electrophoresis (DGGE) and nonmetric multidimensional scaling analysis. Stations in the Sulu Sea and the adjacent areas showed much more prominent vertical stratification of bacterial community structures than horizontal variation. As predominant sequences, cyanobacteria and α-proteobacteria at 10 m depth, δ-proteobacteria at 100 m depth, and green nonsulfur bacteria below 1000 m depth were detected in all sampling areas. High temperatures and low oxygen concentrations are thought to be minor factors in controlling community structure; the quantity and quality of organic materials supplied by the sinking particles, and hydrostatic pressure are believed to be important.

  3. Ion channels and cancer.

    PubMed

    Kunzelmann, Karl

    2005-06-01

    Membrane ion channels are essential for cell proliferation and appear to have a role in the development of cancer. This has initially been demonstrated for potassium channels and is meanwhile also suggested for other cation channels and Cl- channels. For some of these channels, like voltage-gated ether à go-go and Ca2+-dependent potassium channels as well as calcium and chloride channels, a cell cycle-dependent function has been demonstrated. Along with other membrane conductances, these channels control the membrane voltage and Ca2+ signaling in proliferating cells. Homeostatic parameters, such as the intracellular ion concentration, cytosolic pH and cell volume, are also governed by the activity of ion channels. Thus it will be an essential task for future studies to unravel cell cycle-specific effects of ion channels and non-specific homeostatic functions. When studying the role of ion channels in cancer cells, it is indispensable to choose experimental conditions that come close to the in vivo situation. Thus, environmental parameters, such as low oxygen pressure, acidosis and exposure to serum proteins, have to be taken into account. In order to achieve clinical application, more studies on the original cancer tissue are required, and improved animal models. Finally, it will be essential to generate more potent and specific inhibitors of ion channels to overcome the shortcomings of some of the current approaches.

  4. Molecular dynamics of alamethicin transmembrane channels from open-channel current noise analysis.

    PubMed Central

    Mak, D O; Webb, W W

    1995-01-01

    Conductance noise measurement of the open states of alamethicin transmembrane channels reveals excess noise attributable to cooperative low-frequency molecular dynamics that can generate fluctuations approximately 1 A rms in the effective channel pore radius. Single-channel currents through both persistent and nonpersistent channels with multiple conductance states formed by purified polypeptide alamethicin in artificial phospholipid bilayers isolated onto micropipettes with gigaohm seals were recorded using a voltage-clamp technique with low background noise (rms noise < 3 pA up to 20 kHz). Current noise power spectra between 100 Hz and 20 kHz of each open channel state showed little frequency dependence. Noise from undetected conductance state transitions was insignificant. Johnson and shot noises were evaluated. Current noise caused by electrolyte concentration fluctuation via diffusion was isolated by its dependence on buffer concentration. After removing these contributions, significant current noise remains in all persistent channel states and increases in higher conductance states. In nonpersistent channels, remaining noise occurs primarily in the lowest two states. These fluctuations of channel conductance are attributed to thermal oscillations of the channel molecular conformation and are modeled as a Langevin translational oscillation of alamethicin molecules moving radially from the channel pore, damped mostly by lipid bilayer viscosity. PMID:8599640

  5. Conductive Channel for Energy Transmission

    NASA Astrophysics Data System (ADS)

    Apollonov, Victor V.

    2011-11-01

    For many years the attempts to create conductive channels of big length were taken in order to study the upper atmosphere and to settle special tasks, related to energy transmission. There upon the program of creation of "Impulsar" represents a great interest, as this program in a combination with high-voltage high repetition rate electrical source can be useful to solve the above mentioned problems (N. Tesla ideas for the days of high power lasers). The principle of conductive channel production can be shortly described as follows. The "Impulsar"—laser jet engine vehicle—propulsion take place under the influence of powerful high repetition rate pulse-periodic laser radiation. In the experiments the CO2—laser and solid state Nd:YAG laser systems had been used. Active impulse appears thanks to air breakdown (<30 km) or to the breakdown of ablated material on the board (>30 km), placed in the vicinity of the focusing mirror-acceptor of the breakdown waves. With each pulse of powerful laser the device rises up, leaving a bright and dense trace of products with high degree of ionization and metallization by conductive nano-particles due to ablation. Conductive dust plasma properties investigation in our experiments was produced by two very effective approaches: high power laser controlled ablation and by explosion of wire. Experimental and theoretical results of conductive canal modeling will be presented. The estimations show that with already experimentally demonstrated figures of specific thrust impulse the lower layers of the Ionosphere can be reached in several ten seconds that is enough to keep the high level of channel conductivity and stability with the help of high repetition rate high voltage generator. Some possible applications for new technology are highlighted.

  6. Conductive Channel for Energy Transmission

    SciTech Connect

    Apollonov, Victor V.

    2011-11-10

    For many years the attempts to create conductive channels of big length were taken in order to study the upper atmosphere and to settle special tasks, related to energy transmission. There upon the program of creation of 'Impulsar' represents a great interest, as this program in a combination with high-voltage high repetition rate electrical source can be useful to solve the above mentioned problems (N. Tesla ideas for the days of high power lasers). The principle of conductive channel production can be shortly described as follows. The 'Impulsar' - laser jet engine vehicle - propulsion take place under the influence of powerful high repetition rate pulse-periodic laser radiation. In the experiments the CO{sub 2}-laser and solid state Nd:YAG laser systems had been used. Active impulse appears thanks to air breakdown (<30 km) or to the breakdown of ablated material on the board (>30 km), placed in the vicinity of the focusing mirror-acceptor of the breakdown waves. With each pulse of powerful laser the device rises up, leaving a bright and dense trace of products with high degree of ionization and metallization by conductive nano-particles due to ablation. Conductive dust plasma properties investigation in our experiments was produced by two very effective approaches: high power laser controlled ablation and by explosion of wire. Experimental and theoretical results of conductive canal modeling will be presented. The estimations show that with already experimentally demonstrated figures of specific thrust impulse the lower layers of the Ionosphere can be reached in several ten seconds that is enough to keep the high level of channel conductivity and stability with the help of high repetition rate high voltage generator. Some possible applications for new technology are highlighted.

  7. Role of adjacency-matrix degeneracy in maximum-entropy-weighted network models

    NASA Astrophysics Data System (ADS)

    Sagarra, O.; Pérez Vicente, C. J.; Díaz-Guilera, A.

    2015-11-01

    Complex network null models based on entropy maximization are becoming a powerful tool to characterize and analyze data from real systems. However, it is not easy to extract good and unbiased information from these models: A proper understanding of the nature of the underlying events represented in them is crucial. In this paper we emphasize this fact stressing how an accurate counting of configurations compatible with given constraints is fundamental to build good null models for the case of networks with integer-valued adjacency matrices constructed from an aggregation of one or multiple layers. We show how different assumptions about the elements from which the networks are built give rise to distinctively different statistics, even when considering the same observables to match those of real data. We illustrate our findings by applying the formalism to three data sets using an open-source software package accompanying the present work and demonstrate how such differences are clearly seen when measuring network observables.

  8. MHD forced convection flow adjacent to a non-isothermal wedge

    SciTech Connect

    Yih, K.A.

    1999-08-01

    The problem of magnetohydrodynamic (MHD) incompressible viscous flow has many important engineering applications in devices such as MHD power generator and the cooling of reactors. In this analysis, the effects of viscous dissipation and stress work on the MHD forced convection adjacent to a non-isothermal wedge is numerically analyzed. These partial differential equations are transformed into the nonsimilar boundary layer equations and solved by the Keller box method. Numerical results for the local friction coefficient and the local Nusselt number are presented for the pressure gradient parameter m, the magnetic parameter {xi}, the Prandtl number Pr, and the Eckert number Ec. In general, increasing the pressure gradient parameter m or the magnetic parameter {xi} or the Prandtl number Pr or decreasing the Eckert number EC increases the local Nusselt number.

  9. Ion channels in plants

    PubMed Central

    Baluška, František; Mancuso, Stefano

    2013-01-01

    In his recent opus magnum review paper published in the October issue of Physiology Reviews, Rainer Hedrich summarized the field of plant ion channels.1 He started from the earliest electric recordings initiated by Charles Darwin of carnivorous Dionaea muscipula,1,2 known as Venus flytrap, and covered the topic extensively up to the most recent discoveries on Shaker-type potassium channels, anion channels of SLAC/SLAH families, and ligand-activated channels of glutamate receptor-like type (GLR) and cyclic nucleotide-gated channels (CNGC).1 PMID:23221742

  10. Cardiac ion channels

    PubMed Central

    Priest, Birgit T; McDermott, Jeff S

    2015-01-01

    Ion channels are critical for all aspects of cardiac function, including rhythmicity and contractility. Consequently, ion channels are key targets for therapeutics aimed at cardiac pathophysiologies such as atrial fibrillation or angina. At the same time, off-target interactions of drugs with cardiac ion channels can be the cause of unwanted side effects. This manuscript aims to review the physiology and pharmacology of key cardiac ion channels. The intent is to highlight recent developments for therapeutic development, as well as elucidate potential mechanisms for drug-induced cardiac side effects, rather than present an in-depth review of each channel subtype. PMID:26556552

  11. A large iris-like expansion of a mechanosensitive channel protein induced by membrane tension

    NASA Technical Reports Server (NTRS)

    Betanzos, Monica; Chiang, Chien-Sung; Guy, H. Robert; Sukharev, Sergei

    2002-01-01

    MscL, a bacterial mechanosensitive channel of large conductance, is the first structurally characterized mechanosensor protein. Molecular models of its gating mechanisms are tested here. Disulfide crosslinking shows that M1 transmembrane alpha-helices in MscL of resting Escherichia coli are arranged similarly to those in the crystal structure of MscL from Mycobacterium tuberculosis. An expanded conformation was trapped in osmotically shocked cells by the specific bridging between Cys 20 and Cys 36 of adjacent M1 helices. These bridges stabilized the open channel. Disulfide bonds engineered between the M1 and M2 helices of adjacent subunits (Cys 32-Cys 81) do not prevent channel gating. These findings support gating models in which interactions between M1 and M2 of adjacent subunits remain unaltered while their tilts simultaneously increase. The MscL barrel, therefore, undergoes a large concerted iris-like expansion and flattening when perturbed by membrane tension.

  12. SEISMIC RESPONSE PREDICTION OF NUPEC'S FIELD MODEL TESTS OF NPP STRUCTURES WITH ADJACENT BUILDING EFFECT.

    SciTech Connect

    XU,J.COSTANTINO,C.HOFMAYER,C.ALI,S.

    2004-03-04

    As part of a verification test program for seismic analysis computer codes for Nuclear Power Plant (NPP) structures, the Nuclear Power Engineering Corporation (NUPEC) of Japan has conducted a series of field model tests to address the dynamic cross interaction (DCI) effect on the seismic response of NPP structures built in close proximity to each other. The program provided field data to study the methodologies commonly associated with seismic analyses considering the DCI effect. As part of a collaborative program between the United States and Japan on seismic issues related to NPP applications, the U.S. Nuclear Regulatory Commission sponsored a program at Brookhaven National Laboratory (BNL) to perform independent seismic analyses which applied common analysis procedures to predict the building response to recorded earthquake events for the test models with DCI effect. In this study, two large-scale DCI test model configurations were analyzed: (1) twin reactor buildings in close proximity and (2) adjacent reactor and turbine buildings. This paper describes the NUPEC DCI test models, the BNL analysis using the SASSI 2000 program, and comparisons between the BNL analysis results and recorded field responses. To account for large variability in the soil properties, the conventional approach of computing seismic responses with the mean, mean plus and minus one-standard deviation soil profiles is adopted in the BNL analysis and the three sets of analysis results were used in the comparisons with the test data. A discussion is also provided in the paper to address (1) the capability of the analysis methods to capture the DCI effect, and (2) the conservatism of the practice for considering soil variability in seismic response analysis for adjacent NPP structures.

  13. Charged and Neutral Particles Channeling Phenomena Channeling 2008

    NASA Astrophysics Data System (ADS)

    Dabagov, Sultan B.; Palumbo, Luigi

    2010-04-01

    -- Probing channeling radiation influenced by ultrasound / W. Wagner ... [et al.] -- Radiation characteristics under electrons planar channeling and quasichanneling in complex crystals / L. Gevorgian -- Formation of relativistic positron atoms by axially channeled positrons and their decay on [symbol]-rays / A. Gevorkyan, A. R. Mkrtchyan and K. Oganesyan -- New features of diffracted channeling radiation from electrons in Si and LiF Crystals / K. B. Korotchenko, Yu. L. Pivovarov and T. A. Tukhfatullin -- Modulated particle beam in a crystal channel / A. Kostyuk ... [et al.] -- Computer simulations of resonant coherent excitation of heavy hydrogenlike ions under planar channeling / A. A. Babaev and Yu. L. Pivovarov -- Parametric x-ray and diffracted transition radiation of 4.5 GeV electrons in diamond / R. O. Avakian ... [et al.] -- Possible use of small accelerators in student laboratory for engineering education / I. Endo, M. Tanaka and T. Yoshimura.The Status of the SPARC Project / A. Cianchi -- Laser-plasma acceleration: first experimental results from the Plasmon-X Project / L. A. Gizzi ... [et al.] -- The powerful nanosecond duration electron beam effect on the crystalline tungsten target / Y. N. Adischev ... [et al.] -- "Shadowing" of the electromagnetic field of a relativistic electron / G. Naumenko ... [et al.] -- The acceleration of the charged particles in a low temperature acoustoplasma / A. S. Abrahamyan, A. R. Mkrtchyan and R. B. Kostanyan -- The experimental study of the surface current excitation by a relativistic electron electromagnetic field / G. A. Naumenko ... [et al.] -- Synchrotron radiation from a charge moving along helical orbit around a dielectric cylinder / A. A. Saharian and A. S. Kotanjyan -- Particle acceleration in a helical wave guide / X. Artru and C. Ray -- Effect of heavy ion charge fluctuations on Cherenkov radiation / V. S. Malyshevsky -- Hard photons powerful radiation of electron bunch interacting with plasma beat waves / A. Shamamian

  14. Contrasting Patterns of Fine Fluvial Sediment Delivery in Two Adjacent Upland Catchments

    NASA Astrophysics Data System (ADS)

    Perks, M.; Bracken, L.; Warburton, J.

    2010-12-01

    Quantifying patterns of fine suspended sediment transfer in UK upland rivers is of vital importance in combating the damaging effects of elevated fluxes of suspended sediment, and sediment associated transport of contaminants, on in-stream biota. In many catchments of the UK there is still a lack of catchment-wide understanding of both the spatial patterns and temporal variation in fine sediment delivery. This poster describes the spatial and temporal distribution of in-stream fine sediment delivery from a network of 44 time-integrated mass flux samplers (TIMs) in two adjacent upland catchments. The two catchments are the Esk (210 km2) and Upper Derwent (236 km2) which drain the North York Moors National Park. Annual suspended sediment loads in the Upper Derwent are 1273 t, whereas in the Esk catchment they are greater at 1778 t. Maximum yields of 22 t km-2 yr -1 were measured in the headwater tributaries of the Rye River (Derwent), whereas peak yields in the Esk are four times greater (98 t km-2 yr-1) on the Butter Beck subcatchment. Analysis of the within-storm sediment dynamics, indicates that the sediment sources within the Upper Derwent catchment are from distal locations possibly mobilised by hillslope runoff processes, whereas in the Esk, sediment sources are more proximal to the channel e.g. within channel stores or bank failures. These estimates of suspended sediment flux are compared with the diffuse pollution potential generated by a risk-based model of sediment transfer (SCIMAP) in order to assess the similarity between the model predictions and observed fluxes.

  15. C. elegans TRP channels.

    PubMed

    Xiao, Rui; Xu, X Z Shawn

    2011-01-01

    Transient receptor potential (TRP) channels represent a superfamily of cation channels found in all eukaryotes. The C. elegans genome encodes seventeen TRP channels covering all of the seven TRP subfamilies. Genetic analyses in C. elegans have implicated TRP channels in a wide spectrum of behavioral and physiological processes, ranging from sensory transduction (e.g. chemosensation, touch sensation, proprioception and osmosensation) to fertilization, drug dependence, organelle biogenesis, apoptosis, gene expression, and neurotransmitter/hormone release. Many C. elegans TRP channels share similar activation and regulatory mechanisms with their vertebrate counterparts. Studies in C. elegans have also revealed some previously unrecognized functions and regulatory mechanisms of TRP channels. C. elegans represents an excellent genetic model organism for the study of function and regulation of TRP channels in vivo. PMID:21290304

  16. Mechanically Activated Ion Channels

    PubMed Central

    Ranade, Sanjeev S.; Syeda, Ruhma; Patapoutian, Ardem

    2015-01-01

    Mechanotransduction, the conversion of physical forces into biochemical signals, is an essential component of numerous physiological processes including not only conscious senses of touch and hearing, but also unconscious senses such as blood pressure regulation. Mechanically activated (MA) ion channels have been proposed as sensors of physical force, but the identity of these channels and an understanding of how mechanical force is transduced has remained elusive. A number of recent studies on previously known ion channels along with the identification of novel MA ion channels have greatly transformed our understanding of touch and hearing in both vertebrates and invertebrates. Here, we present an updated review of eukaryotic ion channel families that have been implicated in mechanotransduction processes and evaluate the qualifications of the candidate genes according to specified criteria. We then discuss the proposed gating models for MA ion channels and highlight recent structural studies of mechanosensitive potassium channels. PMID:26402601

  17. C. elegans TRP channels

    PubMed Central

    Xiao, Rui; Xu, X.Z. Shawn

    2010-01-01

    TRP (transient receptor potential) channels represent a superfamily of cation channels found in all eukaryotes. The C. elegans genome encodes seventeen TRP channels covering all of the seven TRP subfamilies. Genetic analyses in C. elegans have implicated TRP channels in a wide spectrum of behavioral and physiological processes, ranging from sensory transduction (e.g. chemosensation, touch sensation, proprioception and osmosensation) to fertilization, drug dependence, organelle biogenesis, apoptosis, gene expression, and neurotransmitter/hormone release. Many C. elegans TRP channels share similar activation and regulatory mechanisms with their vertebrate counterparts. Studies in C. elegans have also revealed some previously unrecognized functions and regulatory mechanisms of TRP channels. C. elegans represents an excellent genetic model organism for the study of function and regulation of TRP channels in vivo. PMID:21290304

  18. GMSK co-channel demodulation

    NASA Astrophysics Data System (ADS)

    Nelson, D. J.; Hopkins, J. R.

    2009-08-01

    Gaussian Minimum Shift Keying (GMSK) is a modulation method used by GSM phone networks and the Automatic Identification System (AIS) used by commercial ships. Typically these systems transmit data in short bursts and accomodate a large number of users by time, frequency and power management. Co-channel interference is not a problem unless the system is heavily loaded. This system load is a function of the density of users and the footprint of the receiver. We consider the problem of demodulation of burst GMSK signals in the presence of severe noise and co-channel interference. We further examine the problem of signal detection and blind estimation and tracking of all of the parameters required in the demodulation process. These parameters include carrier frequency, carrier phase, baud rate, baud phase, modulation index and the start and duration of the signal.

  19. High Resolution Photogrammetric Digital Elevation Models Across Calving Fronts and Meltwater Channels in Greenland

    NASA Astrophysics Data System (ADS)

    Le Bel, D. A.; Brown, S.; Zappa, C. J.; Bell, R. E.; Frearson, N.; Tinto, K. J.

    2014-12-01

    Photogrammetric digital elevation models (DEMs) are a powerful approach for understanding elevation change and dynamics along the margins of the large ice sheets. The IcePod system, mounted on a New York Air National Guard LC-130, can measure high-resolution surface elevations with a Riegl VQ580 scanning laser altimeter and Imperx Bobcat IGV-B6620 color visible-wavelength camera (6600x4400 resolution); the surface temperature with a Sofradir IRE-640L infrared camera (spectral response 7.7-9.5 μm, 640x512 resolution); and the structure of snow and ice with two radar systems. We show the use of IcePod imagery to develop DEMs across calving fronts and meltwater channels in Greenland. Multiple over-flights of the Kangerlussaq Airport ramp have provided a test of the technique at a location with accurate, independently-determined elevation. Here the photogrammetric DEM of the airport, constrained by ground control measurements, is compared with the Lidar results. In July 2014 the IcePod ice-ocean imaging system surveyed the calving fronts of five outlet glaciers north of Jakobshavn Isbrae. We used Agisoft PhotoScan to develop a DEM of each calving front using imagery captured by the IcePod systems. Adjacent to the ice sheet, meltwater plumes foster mixing in the fjord, moving warm ocean water into contact with the front of the ice sheet where it can undercut the ice front and trigger calving. The five glaciers provide an opportunity to examine the calving front structure in relation to ocean temperature, fjord circulation, and spatial scale of the meltwater plumes. The combination of the accurate DEM of the calving front and the thermal imagery used to constrain the temperature and dynamics of the adjacent plume provides new insights into the ice-ocean interactions. Ice sheet margins provide insights into the connections between the surface meltwater and the fate of the water at the ice sheet base. Surface meltwater channels are visualized here for the first time using

  20. Laser ablation of human atherosclerotic plaque without adjacent tissue injury

    NASA Technical Reports Server (NTRS)

    Grundfest, W. S.; Litvack, F.; Forrester, J. S.; Goldenberg, T.; Swan, H. J. C.

    1985-01-01

    Seventy samples of human cadaver atherosclerotic aorta were irradiated in vitro using a 308 nm xenon chloride excimer laser. Energy per pulse, pulse duration and frequency were varied. For comparison, 60 segments were also irradiated with an argon ion and an Nd:YAG laser operated in the continuous mode. Tissue was fixed in formalin, sectioned and examined microscopically. The Nd:YAG and argon ion-irradiated tissue exhibited a central crater with irregular edges and concentric zones of thermal and blast injury. In contrast, the excimer laser-irradiated tissue had narrow deep incisions with minimal or no thermal injury. These preliminary experiments indicate that the excimer laser vaporizes tissue in a manner different from that of the continuous wave Nd:YAG or argon ion laser. The sharp incision margins and minimal damage to adjacent normal tissue suggest that the excimer laser is more desirable for general surgical and intravascular uses than are the conventionally used medical lasers.

  1. GOAT ROCKS WILDERNESS AND ADJACENT ROADLESS AREAS, WASHINGTON.

    USGS Publications Warehouse

    Church, S.E.; Close, T.J.

    1984-01-01

    The Goat Rocks Wilderness and adjacent roadless areas are a rugged, highly forested, scenic area located on the crest of the Cascade Range in south-central Washington. Several mineral claims have been staked in the area. Mineral surveys were conducted. Geochemical, geophysical, and geologic investigations indicate that three areas have probable mineral-resource potential for base metals in porphyry-type deposits. Available data are not adequate to permit definition of the potential for oil and gas. There is little likelihood for the occurrence of other kinds of energy resources in the area. Evaluation of resource potential in the three areas identified as having probable mineral-resource potential could be improved by more detailed geochemical studies and geologic mapping.

  2. Scolopendromorpha of New Guinea and adjacent islands (Myriapoda, Chilopoda).

    PubMed

    Schileyko, Arkady A; Stoev, Pavel E

    2016-01-01

    The centipede fauna of the second largest island in the world, New Guinea, and its adjacent islands, is poorly known, with most information deriving from the first half of the 20th century. Here we present new data on the order Scolopendromorpha based on material collected in the area in the last 40 years, mainly by Bulgarian and Latvian zoologists. The collections comprise eleven species of six genera and three families. The diagnosis of Cryptops (Trigonocryptops) is emended in the light of the recent findings. The old and doubtful record of Scolopendra multidens Newport, 1844 from New Guinea is referred to S. subspinipes Leach, 1815 and the species is here excluded from the present day list of New Guinean scolopendromorphs. Cryptops nepalensis Lewis, 1999 is here recorded from New Guinea for the first time. An annotated list and an identification key to the scolopendromorphs of the studied region are presented. PMID:27515618

  3. Geomorphology of portions of western Kentucky and adjacent areas

    SciTech Connect

    Dilamarter, R.C.

    1982-07-01

    The geomorphology of portions of western Kentucky and adjacent areas in Indiana, Illinois and Tennessee is presented as a background for interpreters evaluating the present land surface using remotely sensed imagery. Eight physiographic units were analyzed and are briefly discussed with reference to topography and surface deposits. Great diversity was found to be characteristic of the region, the result of different structural influences and geomorphic processes. The landscape bears the marks of fluvial, glacial, eolian, lacustrine and karstic environments, so a regional geomorphic history was compiled from the literature as an aid to understanding the land surface. Three smaller zones in Kentucky were analyzed in greater detail regarding topography and geomorphic development because of their potential importance in subsurface exploration.

  4. Configuration optimization of dampers for adjacent buildings under seismic excitations

    NASA Astrophysics Data System (ADS)

    Bigdeli, Kasra; Hare, Warren; Tesfamariam, Solomon

    2012-12-01

    Passive coupling of adjacent structures is known to be an effective method to reduce undesirable vibrations and structural pounding effects. Past results have shown that reducing the number of dampers can considerably decrease the cost of implementation and does not significantly decrease the efficiency of the system. The main objective of this study was to find the optimal arrangement of a limited number of dampers to minimize interstorey drift. Five approaches to solving the resulting bi-level optimization problem are introduced and examined (exhaustive search, inserting dampers, inserting floors, locations of maximum relative velocity and a genetic algorithm) and the numerical efficiency of each method is examined. The results reveal that the inserting damper method is the most efficient and reliable method, particularly for tall structures. It was also found that increasing the number of dampers does not necessarily increase the efficiency of the system. In fact, increasing the number of dampers can exacerbate the dynamic response of the system.

  5. Reconnaissance geologic map of Kodiak Island and adjacent islands, Alaska

    USGS Publications Warehouse

    Wilson, Frederic H.

    2013-01-01

    Kodiak Island and its adjacent islands, located on the west side of the Gulf of Alaska, contain one of the largest areas of exposure of the flysch and melange of the Chugach terrane of southern Alaska. However, in the past 25 years, only detailed mapping covering small areas in the archipelago has been done. This map and its associated digital files (Wilson and others, 2005) present the best available mapping compiled in an integrated fashion. The map and associated digital files represent part of a systematic effort to release geologic map data for the United States in a uniform manner. The geologic data have been compiled from a wide variety of sources, ranging from state and regional geologic maps to large-scale field mapping. The map data are presented for use at a nominal scale of 1:500,000, although individual datasets (see Wilson and others, 2005) may contain data suitable for use at larger scales.

  6. 38. METAL WORKING TOOLS AND MACHINES ADJACENT TO THE CIRCA ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    38. METAL WORKING TOOLS AND MACHINES ADJACENT TO THE CIRCA 1900 MICHIGAN MACHINERY MFG. CO. PUNCH PRESS NEAR THE CENTER OF THE FACTORY BUILDING. AT THE LEFT FOREGROUND IS A MOVABLE TIRE BENDER FOR SHAPING ELI WINDMILL WHEEL RIMS. AT THE CENTER IS A FLOOR-MOUNTED CIRCA 1900 SNAG GRINDER OF THE TYPE USED FOR SMOOTHING ROUGH CASTINGS. ON THE WHEELED WORK STATION IS A SUNNEN BUSHING GRINDER, BEHIND WHICH IS A TRIPOD CHAIN VICE. IN THE CENTER BACKGROUND IS A WOODEN CHEST OF DRAWERS WHICH CONTAINS A 'RAG DRAWER' STILL FILLED WITH CLOTH RAGS PLACED IN THE FACTORY BUILDING AT THE INSISTENCE OF LOUISE (MRS. ARTHUR) KREGEL FOR THE CONVENIENCE AND CLEANLINESS OF WORKERS. IN THE LEFT BACKGROUND IS A CIRCA 1900 CROSS-CUTOFF CIRCULAR SAW. - Kregel Windmill Company Factory, 1416 Central Avenue, Nebraska City, Otoe County, NE

  7. Air bubble-shock wave interaction adjacent to gelantine surface

    NASA Astrophysics Data System (ADS)

    Lush, P. A.; Tomita, Y.; Onodera, O.; Takayama, K.; Sanada, N.; Kuwahara, M.; Ioritani, N.; Kitayama, O.

    1990-07-01

    The interaction between a shock wave and an air bubble-adjacent to a gelatine surface is investigated in order to simulate human tissue damage resulting from extracorporeal shock wave lithotripsy. Using high speed cine photography it is found that a shock wave of strength 11 MPa causes 1-3 mm diameter bubbles to produce high velocity microjets with penetration rates of approximately 110 m/s and penetration depths approximately equal to twice the initial bubble diameter. Theoretical considerations for liquid impact on soft solid of similar density indicate that microjet velocities will be twice the penetration rate, i.e. 220 m/s in the present case. Such events are the probable cause of observed renal tissue damage.

  8. Effect of Fluoridated Sealants on Adjacent Tooth Surfaces

    PubMed Central

    Cagetti, M.G.; Carta, G.; Cocco, F.; Sale, S.; Congiu, G.; Mura, A.; Strohmenger, L.; Lingström, P.; Campus, G.

    2014-01-01

    A double-blind randomized clinical trial was performed in 6- to 7-yr-old schoolchildren to evaluate, in a 30-mo period, whether the caries increment on the distal surface of the second primary molars adjacent to permanent first molars sealed with fluoride release compounds would be lower with respect to those adjacent to permanent first molars sealed with a nonfluoridated sealant. In sum, 2,776 subjects were enrolled and randomly divided into 3 groups receiving sealants on sound first molars: high-viscosity glass ionomer cement (GIC group); resin-based sealant with fluoride (fluoride-RB group); and a resin-based sealant without fluoride (RB group). Caries (D1 – D3 level) was recorded on the distal surface of the second primary molar, considered the unit of analysis including only sound surfaces at the baseline. At baseline, no differences in caries prevalence were recorded in the 3 groups regarding the considered surfaces. At follow-up, the prevalence of an affected unit of analysis was statistically lower (p = .03) in the GIC and fluoride-RB groups (p = .04). In the GIC group, fewer new caries were observed in the unit of analysis respect to the other 2 groups. Incidence rate ratios (IRRs) were 0.70 (95% confidence interval: 0.50, 0.68; p < .01) for GIC vs. RB and 0.79 (95% confidence interval: 0.53, 1.04; p = .005) for fluoride-RB vs. RB. Caries incidence was significantly associated with low socioeconomic status (IRR = 1.18; 95% confidence interval: 1.10, 1.42; p = .05). Dental sealant high-viscosity GIC and fluoride-RB demonstrated protection against dental caries, and there was evidence that these materials afforded additional protection for the tooth nearest to the sealed tooth (clinical trial registration NCT01588210). PMID:24846910

  9. Subduction initiation adjacent to a relic island arc

    NASA Astrophysics Data System (ADS)

    Leng, W.; Gurnis, M.

    2013-12-01

    Although plate tectonics is well established, how subduction initiates over tectonic history has remained obscure. It has been proposed that passive margins may be a possible place for subduction initiation, but there is no obvious Cenozoic example of such a scenario, including along the passive margins of the Atlantic Ocean. With a computational method that follows the deformation of a visco-elasto-plastic medium, here we show that a favourable locale for subduction initiation is the juxtaposition of an old oceanic plate adjacent to a young, but relic arc. Significant density anomalies leading to subduction initiation arise from two major factors. One is the compositional difference between the relic arc crust and the oceanic lithospheric mantle; the other is the thermal difference due to the age offset between the two plates. With such a setup, we observe spontaneous subduction initiation if the oceanic crust is significantly weakened by pore fluid pressure. If the oceanic crust is relatively strong, a small amount of plate convergence is required to induce subduction. The evidence that Izu-Bonin-Mariana and Tonga-Kermedec subduction zones both initiate adjacent to a relic island arc support our conclusions. The initiation of both subduction zones at 51-52 Ma with commensurate compression on their respective overriding plates support a causal link between both subduction initiation events through a change in Pacific Plate motion. Our results provide an explanation for the rarity of subduction initiation at the passive margins. The continental lithosphere is typically old and cold. Consequently, the thermal effects cancel the compositional buoyancy contrast between the continental crust and the oceanic lithospheric mantle, making subduction initiation difficult at passive margins.

  10. Prevention of enamel demineralization adjacent to glass ionomer filling materials.

    PubMed

    Forss, H; Seppä, L

    1990-04-01

    In order to study the release of fluoride and prevention of enamel demineralization by different filling materials, standardized cavities were prepared in 80 extracted human molars. The cavities were filled as follows: 1. Fuji II F; 2. Ketac-Fil; 3. Ketac-Silver; 4. Silar. Twenty molars were used as controls (no filling). Enamel slabs with the fillings were subjected to 9 days of demineralization (30 min daily) and remineralization (artificial saliva, replaced daily). Fluoride release in the saliva was determined on days 1, 3, 5, and 9. Enamel fluoride content adjacent to the cavities was determined initially and after the de-remineralization using the acid etch technique. On day 1, the largest amount of fluoride in the saliva was released by Fuji, but on day 9 the largest amount was released by Ketac-Fil. Ketac-Silver released significantly less fluoride than Fuji and Ketac-Fil. The average initial fluoride content of enamel was 2200 ppm. After the test period, fluoride contents adjusted for biopsy depth were 1822, 1690, 1693, 1337, and 888 ppm in groups 1-5, respectively. The amounts of phosphorus dissolved by the second acid etch were 28.9 (SE 2.6), 30.2 (2.0), 34.4 (2.8), 44.1 (2.7), and 42.2 (2.4) micrograms, respectively. Softening of surface enamel during the test period was clearly reduced in teeth filled with Fuji and Ketac-Fil. The results show that glass ionomer materials release considerable amounts of fluoride and prevent demineralization of the adjacent enamel in vitro. Fuji and Ketac-Fil seem to be more effective than Ketac-Silver.

  11. 33 CFR 110.140 - Buzzards Bay, Nantucket Sound, and adjacent waters, Mass.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., and adjacent waters, Mass. 110.140 Section 110.140 Navigation and Navigable Waters COAST GUARD..., Nantucket Sound, and adjacent waters, Mass. Link to an amendment published at 76 FR 35744, June 20, 2011. (a... adjacent waters, Mass. (a) * * * (2) Anchorage B. All waters bounded by a line beginning at 41°36′42.3″...

  12. Channel stability of Turkey Creek, Nebraska

    USGS Publications Warehouse

    Rus, David L.; Soenksen, Philip J.

    1998-01-01

    Channelization on Turkey Creek and its receiving stream, the South Fork Big Nemaha River, has disturbed the equilibrium of Turkey Creek and has led to channel-stability problems, such as degradation and channel widening, which pose a threat to bridges and land adjacent to the stream. As part of a multiagency study, the U.S. Geological Survey assessed channel stability at two bridge sites on upper and middle portions of Turkey Creek by analyzing streambed-elevation data for gradation changes, comparing recent cross-section surveys and historic accounts, identifying bank-failure blocks, and analyzing tree-ring samples. These results were compared to gradation data and trend results for a U.S. Geological Survey streamflow-gaging station near the mouth of Turkey Creek from a previous study. Examination of data on streambed elevations reveals that degradation has occurred. The streambed elevation declined 0.5 m at the upper site from 1967-97. The streambed elevation declined by 3.2 m at the middle site from 1948-97 and exposed 2 m of the pilings of the Nebraska Highway 8 bridge. Channel widening could not be verified at the two sites from 1967-97, but a historic account indicates widening at the middle site to be two to three times that of the 1949 channel width. Small bank failures were evident at the upper site and a 4-m-wide bank failure occurred at the middle site in 1987 according to tree ring analyses. Examination of streambed-elevation data from a previous study at the lower site reveals a statistically significant aggrading trend from 1958-93. Further examination of these data suggests minor degradation occurred until 1975, followed by aggradation.

  13. Spatial and temporal variability in sedimentation rates associated with cutoff channel infill deposits: Ain River, France

    USGS Publications Warehouse

    Piegay, H.; Hupp, C.R.; Citterio, A.; Dufour, S.; Moulin, B.; Walling, D.E.

    2008-01-01

    Floodplain development is associated with lateral accretion along stable channel geometry. Along shifting rivers, the floodplain sedimentation is more complex because of changes in channel position but also cutoff channel presence, which exhibit specific overflow patterns. In this contribution, the spatial and temporal variability of sedimentation rates in cutoff channel infill deposits is related to channel changes of a shifting gravel bed river (Ain River, France). The sedimentation rates estimated from dendrogeomorphic analysis are compared between and within 14 cutoff channel infills. Detailed analyses along a single channel infill are performed to assess changes in the sedimentation rates through time by analyzing activity profiles of the fallout radionuclides 137Cs and unsupported 210Pb. Sedimentation rates are also compared within the channel infills with rates in other plots located in the adjacent floodplain. Sedimentation rates range between 0.65 and 2.4 cm a -1 over a period of 10 to 40 years. The data provide additional information on the role of distance from the bank, overbank flow frequency, and channel geometry in controlling the sedimentation rate. Channel infills, lower than adjacent floodplains, exhibit higher sedimentation rates and convey overbank sediment farther away within the floodplain. Additionally, channel degradation, aggradation, and bank erosion, which reduce or increase the distance between the main channel and the cutoff channel aquatic zone, affect local overbank flow magnitude and frequency and therefore sedimentation rates, thereby creating a complex mosaic of sedimentation zones within the floodplain and along the cutoff channel infills. Last, the dendrogeomorphic and 137Cs approaches are cross validated for estimating the sedimentation rate within a channel infill. Copyright 2008 by the American Geophysical Union.

  14. Methods of channeling simulation

    SciTech Connect

    Barrett, J.H.

    1989-06-01

    Many computer simulation programs have been used to interpret experiments almost since the first channeling measurements were made. Certain aspects of these programs are important in how accurately they simulate ions in crystals; among these are the manner in which the structure of the crystal is incorporated, how any quantity of interest is computed, what ion-atom potential is used, how deflections are computed from the potential, incorporation of thermal vibrations of the lattice atoms, correlations of thermal vibrations, and form of stopping power. Other aspects of the programs are included to improve the speed; among these are table lookup, importance sampling, and the multiparameter method. It is desirable for programs to facilitate incorporation of special features of interest in special situations; examples are relaxations and enhanced vibrations of surface atoms, easy substitution of an alternate potential for comparison, change of row directions from layer to layer in strained-layer lattices, and different vibration amplitudes for substitutional solute or impurity atoms. Ways of implementing all of these aspects and features and the consequences of them will be discussed. 30 refs., 3 figs.

  15. Late Quaternary history of the southwestern St. Lawrence Lowlands and adjacent Adirondack Highlands

    SciTech Connect

    Pair, D.L. . Dept. of Geology)

    1993-03-01

    The reconstruction of Late Wisconsinan ice retreat, proglacial lakes, and Champlain Sea history from the northwest Adirondack slope and adjacent St. Lawrence Lowlands is critical to the synthesis of a regional picture of deglacial events in the eastern Great Lakes region. Unfortunately, these same areas are well known for their limited exposures, landforms covered by thick forest, large tracts of land inaccessible to detailed field mapping, and the overall paucity of glacial materials preserved on upland surfaces. Despite these limitations, a model which utilizes multiple and field-truthed evidence has been used to designate areas where ice border deposits indicate a substantial recessional position. It employs the following criteria in this analysis: sedimentology and morphostratigraphy of morainal landform segments and related sediments; orientation and continuity of ice border drainage channels; and the relationship of ice borders and drainage systems to well documented local and regional water bodies which accompanied ice retreat. The results of this approach have provided a unique regional picture of deglaciation. Despite the inherent limitations of working in upland areas to reconstruct glacial events, detailed morphostratigraphic correlations based on multiple lines of evidence can yield important information. The positions of five former ice borders have been reconstructed from the available data. These ice margins correspond closely with those documented previously by others adjoining areas. This type of study, utilizing multiple and field-truthed lines of evidence, constitutes a tangible step towards understanding the nature and history of ice retreat along this portion of the Laurentide Ice Sheet.

  16. Fading channel simulator

    DOEpatents

    Argo, Paul E.; Fitzgerald, T. Joseph

    1993-01-01

    Fading channel effects on a transmitted communication signal are simulated with both frequency and time variations using a channel scattering function to affect the transmitted signal. A conventional channel scattering function is converted to a series of channel realizations by multiplying the square root of the channel scattering function by a complex number of which the real and imaginary parts are each independent variables. The two-dimensional inverse-FFT of this complex-valued channel realization yields a matrix of channel coefficients that provide a complete frequency-time description of the channel. The transmitted radio signal is segmented to provide a series of transmitted signal and each segment is subject to FFT to generate a series of signal coefficient matrices. The channel coefficient matrices and signal coefficient matrices are then multiplied and subjected to inverse-FFT to output a signal representing the received affected radio signal. A variety of channel scattering functions can be used to characterize the response of a transmitter-receiver system to such atmospheric effects.

  17. On-track and off-track distance properties of Class 4 partial response channels

    NASA Astrophysics Data System (ADS)

    Soljanin, Emina

    1995-12-01

    We consider Class 4 partial response (PR) channels, and examine off-track performance of maximum likelihood sequence estimators for these channels that ignore inter-track interference (ITI). We assume that the pulse response to the head from an adjacent track is the same Class 4 channel, and only its amplitude varies with the track-to-head distance, in a way not known to the receiver. For each of these channels, we find analytical expressions for off-track performance, as well as sets of sequences most susceptible to errors in the ITI environment. We also discuss how the problem of off-track error rate can be alleviated through coding.

  18. Piecewise uniform conduction-like flow channels and method therefor

    DOEpatents

    Cummings, Eric B.; Fiechtner, Gregory J.

    2006-02-28

    A low-dispersion methodology for designing microfabricated conduction channels for on-chip electrokinetic-based systems is presented. The technique relies on trigonometric relations that apply for ideal electrokinetic flows, allowing faceted channels to be designed on chips using common drafting software and a hand calculator. Flows are rotated and stretched along the abrupt interface between adjacent regions with differing permeability. Regions bounded by interfaces form flow "prisms" that can be combined with other designed prisms to obtain a wide range of turning angles and expansion ratios while minimizing dispersion. Designs are demonstrated using two-dimensional numerical solutions of the Laplace equation.

  19. HIGH POWER PULSED OSCILLATOR

    DOEpatents

    Singer, S.; Neher, L.K.

    1957-09-24

    A high powered, radio frequency pulse oscillator is described for generating trains of oscillations at the instant an input direct voltage is impressed, or immediately upon application of a light pulse. In one embodiment, the pulse oscillator comprises a photo-multiplier tube with the cathode connected to the first dynode by means of a resistor, and adjacent dynodes are connected to each other through adjustable resistors. The ohmage of the resistors progressively increases from a very low value for resistors adjacent the cathode to a high value adjacent the plate, the last dynode. Oscillation occurs with this circuit when a high negative voltage pulse is applied to the cathode and the photo cathode is bombarded. Another embodiment adds capacitors at the resistor connection points of the above circuit to increase the duration of the oscillator train.

  20. Markov modeling of ion channels: implications for understanding disease.

    PubMed

    Lampert, Angelika; Korngreen, Alon

    2014-01-01

    Ion channels are the bridge between the biochemical and electrical domains of our life. These membrane crossing proteins use the electric energy stored in transmembrane ion gradients, which are produced by biochemical activity to generate ionic currents. Each ion channel can be imagined as a small power plant similar to a hydroelectric power station, in which potential energy is converted into electric current. This current drives basically all physiological mechanisms of our body. It is clear that a functional blueprint of these amazing cellular power plants is essential for understanding the principle of all aspects of physiology, particularly neurophysiology. The golden path toward this blueprint starts with the biophysical investigation of ion channel activity and continues through detailed numerical modeling of these channels that will eventually lead to a full system-level description of cellular and organ physiology. Here, we discuss the first two stages of this process focusing on voltage-gated channels, particularly the voltage-gated sodium channel which is neurologically and pathologically important. We first detail the correlations between the known structure of the channel and its activity and describe some pathologies. We then provide a hands-on description of Markov modeling for voltage-gated channels. These two sections of the chapter highlight the dichotomy between the vast amounts of electrophysiological data available on voltage-gated channels and the relatively meager number of physiologically relevant models for these channels.

  1. How semantic biases in simple adjacencies affect learning a complex structure with non-adjacencies in AGL: a statistical account

    PubMed Central

    Poletiek, Fenna H.; Lai, Jun

    2012-01-01

    A major theoretical debate in language acquisition research regards the learnability of hierarchical structures. The artificial grammar learning methodology is increasingly influential in approaching this question. Studies using an artificial centre-embedded AnBn grammar without semantics draw conflicting conclusions. This study investigates the facilitating effect of distributional biases in simple AB adjacencies in the input sample—caused in natural languages, among others, by semantic biases—on learning a centre-embedded structure. A mathematical simulation of the linguistic input and the learning, comparing various distributional biases in AB pairs, suggests that strong distributional biases might help us to grasp the complex AnBn hierarchical structure in a later stage. This theoretical investigation might contribute to our understanding of how distributional features of the input—including those caused by semantic variation—help learning complex structures in natural languages. PMID:22688639

  2. Submicroscopic Ca2+ diffusion mediates inhibitory coupling between individual Ca2+ channels.

    PubMed

    Imredy, J P; Yue, D T

    1992-08-01

    Dihydropyridine-sensitive Ca2+ channels in heart demonstrate an important negative feedback property: they close, or inactivate, in response to prior Ca2+ entry. We now find that Ca2+ influx through one channel can selectively contribute to the inactivation of another adjacent channel, without a generalized elevation of bulk intracellular Ca2+ concentration. Intracellular application of the Ca2+ chelator BAPTA greatly diminishes such negative interactions within Ca2+ channel pairs. These findings demonstrate that Ca2+ currents are controlled not only by intrinsic channel properties, but also by local diffusive interactions among neighboring channels. Such inhibitory coupling among channels provides a concrete example of localized Ca2+ signaling, long proposed to exist on the basis of theoretical calculations. PMID:1323309

  3. Fuel cell plates with improved arrangement of process channels for enhanced pressure drop across the plates

    DOEpatents

    Spurrier, Francis R.; Pierce, Bill L.; Wright, Maynard K.

    1986-01-01

    A plate for a fuel cell has an arrangement of ribs defining an improved configuration of process gas channels and slots on a surface of the plate which provide a modified serpentine gas flow pattern across the plate surface. The channels are generally linear and arranged parallel to one another while the spaced slots allow cross channel flow of process gas in a staggered fashion which creates a plurality of generally mini-serpentine flow paths extending transverse to the longitudinal gas flow along the channels. Adjacent pairs of the channels are interconnected to one another in flow communication. Also, a bipolar plate has the aforementioned process gas channel configuration on one surface and another configuration on the opposite surface. In the other configuration, there are not slots and the gas flow channels have a generally serpentine configuration.

  4. Improvement in fusion reactor performance due to ion channeling

    SciTech Connect

    Emmert, G.A.; El-Guebaly, L.A.; Kulcinski, G.L.; Santarius, J.F.; Sviatoslavsky, I.N.; Meade, D.M.

    1994-11-01

    Ion channeling is a recent idea for improving the performance of fusion reactors by increasing the fraction of the fusion power deposited in the ions. In this paper the authors assess the effect of ion channeling on D-T and D-{sup 3}He reactors. The figures of merit used are the fusion power density and the cost of electricity. It is seen that significant ion channeling can lead to about a 50-65% increase in the fusion power density. For the Apollo D-{sup 3}He reactor concept the reduction in the cost of electricity can be as large as 30%.

  5. Jamming in Vertical Channels

    NASA Astrophysics Data System (ADS)

    Baxter, G. William; Steel, Fiona

    2011-03-01

    We study jamming of low aspect-ratio cylindrical Delrin grains in a vertical channel. Grain heights are less than their diameter so the grains resemble antacid tablets, coins, or poker chips. These grains are allowed to fall through a vertical channel with a square cross section where the channel width is greater than the diameter of a grain and constant throughout the length of the channel with no obstructions or constrictions. Grains are sometimes observed to form jams, stable structures supported by the channel walls with no support beneath them. The probability of jam occurrence and the strength or robustness of a jam is effected by grain and channel sizes. We will present experimental measurements of the jamming probability and jam strength in this system and discuss the relationship of these results to other experiments and theories. Supported by an Undergraduate Research Grant from Penn State Erie, The Behrend College.

  6. Mechanosensitive channels in microbes.

    PubMed

    Kung, Ching; Martinac, Boris; Sukharev, Sergei

    2010-01-01

    All cells, including microbes, detect and respond to mechanical forces, of which osmotic pressure is most ancient and universal. Channel proteins have evolved such that they can be directly stretched open when the membrane is under turgor pressure. Osmotic downshock, as in rain, opens bacterial mechanosensitive (MS) channels to jettison osmolytes, relieving pressure and preventing cell lysis. The ion flux through individual channel proteins can be observed directly with a patch clamp. MS channels of large and small conductance (MscL and MscS, respectively) have been cloned, crystallized, and subjected to biophysical and genetic analyses in depth. They are now models to scrutinize how membrane forces direct protein conformational changes. Eukaryotic microbes have homologs from animal sensory channels of the TRP superfamily. The MS channel in yeast is also directly sensitive to membrane stretch. This review examines the key concept that proteins embedded in the lipid bilayer can respond to the changes in the mechanical environment the lipid bilayer provides.

  7. Amyloid peptide channels.

    PubMed

    Kagan, B L; Azimov, R; Azimova, R

    2004-11-01

    At least 16 distinct clinical syndromes including Alzheimer's disease (AD), Parkinson's disease (PD), rheumatoid arthritis, type II diabetes mellitus (DM), and spongiform encephelopathies (prion diseases), are characterized by the deposition of amorphous, Congo red-staining deposits known as amyloid. These "misfolded" proteins adopt beta-sheet structures and aggregate spontaneously into similar extended fibrils despite their widely divergent primary sequences. Many, if not all, of these peptides are capable of forming ion-permeable channels in vitro and possibly in vivo. Common channel properties include irreversible, spontaneous insertion into membranes, relatively large, heterogeneous single-channel conductances, inhibition of channel formation by Congo red, and blockade of inserted channels by Zn2+. Physiologic effects of amyloid, including Ca2+ dysregulation, membrane depolarization, mitochondrial dysfunction, inhibition of long-term potentiation (LTP), and cytotoxicity, suggest that channel formation in plasma and intracellular membranes may play a key role in the pathophysiology of the amyloidoses. PMID:15702375

  8. HIPPI and Fibre Channel

    SciTech Connect

    Tolmie, D.E.

    1992-01-01

    The High-Performance Parallel Interface (HIPPI) and Fibre Channel are near-gigabit per second data communications interfaces being developed in ANSI standards Task Group X3T9.3. HIPPI is the current interface of choice in the high-end and supercomputer arena, and Fibre Channel is a follow-on effort. HIPPI came from a local area network background, and Fibre Channel came from a mainframe to peripheral interface background.

  9. Can Nonprivate Channels Transmit Quantum Information?

    NASA Astrophysics Data System (ADS)

    Smith, Graeme; Smolin, John A.

    2009-01-01

    We study the power of quantum channels with little or no capacity for private communication. Because privacy is a necessary condition for quantum communication, one might expect that such channels would be of little use for transmitting quantum states. Nevertheless, we find strong evidence that there are pairs of such channels that, when used together, can transmit far more quantum information than the sum of their individual private capacities. Because quantum transmissions are necessarily private, this would imply a large violation of additivity for the private capacity. Specifically, we present channels which display either (1) a large joint quantum capacity but very small individual private capacities or (2) a severe violation of additivity for the Holevo information.

  10. Symmetrization for redundant channels

    NASA Technical Reports Server (NTRS)

    Tulplue, Bhalchandra R. (Inventor); Collins, Robert E. (Inventor)

    1988-01-01

    A plurality of redundant channels in a system each contain a global image of all the configuration data bases in each of the channels in the system. Each global image is updated periodically from each of the other channels via cross channel data links. The global images of the local configuration data bases in each channel are separately symmetrized using a voting process to generate a system signal configuration data base which is not written into by any other routine and is available for indicating the status of the system within each channel. Equalization may be imposed on a suspect signal and a number of chances for that signal to heal itself are provided before excluding it from future votes. Reconfiguration is accomplished upon detecting a channel which is deemed invalid. A reset function is provided which permits an externally generated reset signal to permit a previously excluded channel to be reincluded within the system. The updating of global images and/or the symmetrization process may be accomplished at substantially the same time within a synchronized time frame common to all channels.

  11. Phosphoinositides regulate ion channels

    PubMed Central

    Hille, Bertil; Dickson, Eamonn J.; Kruse, Martin; Vivas, Oscar; Suh, Byung-Chang

    2014-01-01

    Phosphoinositides serve as signature motifs for different cellular membranes and often are required for the function of membrane proteins. Here, we summarize clear evidence supporting the concept that many ion channels are regulated by membrane phosphoinositides. We describe tools used to test their dependence on phosphoinositides, especially phosphatidylinositol 4,5-bisphosphate, and consider mechanisms and biological meanings of phosphoinositide regulation of ion channels. This lipid regulation can underlie changes of channel activity and electrical excitability in response to receptors. Since different intracellular membranes have different lipid compositions, the activity of ion channels still in transit towards their final destination membrane may be suppressed until they reach an optimal lipid environment. PMID:25241941

  12. IBEX channel formation

    SciTech Connect

    Jones, E.E.; Frost, C.A.; Freeman, J.R.; Jojola, J.M.

    1987-01-01

    Exploding wire experiments have been conducted to form a low-density channel for endoatmospheric channel-tracking experiments to be performed on the IBEX accelerator. Stainless steel and tungsten wires as small as six microns radius have been exploded using a 50 kJ, 200 kV fast capacitor bank designed and constructed for the purpose. Density channels have been produced. Preliminary results will be compared with a simple circuit model and hydrocode analysis. Efforts to diagnose the low-density channel are beginning. 5 refs.

  13. Entanglement in channel discrimination with restricted measurements

    SciTech Connect

    Matthews, William; Piani, Marco; Watrous, John

    2010-09-15

    We study the power of measurements implementable with local quantum operations and classical communication (LOCC) measurements in the setting of quantum channel discrimination. More precisely, we consider discrimination procedures that attempt to identify an unknown channel, chosen uniformly from two known alternatives, that take the following form: (i) the input to the unknown channel is prepared in a possibly entangled state with an ancillary system, (ii) the unknown channel is applied to the input system, and (iii) an LOCC measurement is performed on the output and ancillary systems, resulting in a guess for which of the two channels was given. The restriction of the measurement in such a procedure to be an LOCC measurement is of interest because it isolates the entanglement in the initial input-ancillary systems as a resource in the setting of channel discrimination. We prove that there exist channel discrimination problems for which restricted procedures of this sort can be at either of the two extremes: they may be optimal within the set of all discrimination procedures (and simultaneously outperform all strategies that make no use of entanglement), or they may be no better than unentangled strategies (and simultaneously suboptimal within the set of all discrimination procedures).

  14. Channel-facilitated diffusion boosted by particle binding at the channel entrance.

    PubMed

    Pagliara, Stefano; Dettmer, Simon L; Keyser, Ulrich F

    2014-07-25

    We investigate single-file diffusion of Brownian particles in arrays of closely confining microchannels permeated by a variety of attractive optical potentials and connecting two baths with equal particle concentration. We simultaneously test free diffusion in the channel, diffusion in optical traps coupled in the center of the channel, and diffusion in traps extending into the baths. We found that both classes of attractive optical potentials enhance the translocation rate through the channel with respect to free diffusion. Surprisingly, for the latter class of potentials we measure a 40-fold enhancement in the translocation rate with respect to free diffusion and find a sublinear power law dependence of the translocation rate on the average number of particles in the channel. Our results reveal the function of particle binding at the channel entrances for diffusive transport and open the way to a better understanding of membrane transport and design of synthetic membranes with enhanced diffusion rate. PMID:25105657

  15. Channel-Facilitated Diffusion Boosted by Particle Binding at the Channel Entrance

    NASA Astrophysics Data System (ADS)

    Pagliara, Stefano; Dettmer, Simon L.; Keyser, Ulrich F.

    2014-07-01

    We investigate single-file diffusion of Brownian particles in arrays of closely confining microchannels permeated by a variety of attractive optical potentials and connecting two baths with equal particle concentration. We simultaneously test free diffusion in the channel, diffusion in optical traps coupled in the center of the channel, and diffusion in traps extending into the baths. We found that both classes of attractive optical potentials enhance the translocation rate through the channel with respect to free diffusion. Surprisingly, for the latter class of potentials we measure a 40-fold enhancement in the translocation rate with respect to free diffusion and find a sublinear power law dependence of the translocation rate on the average number of particles in the channel. Our results reveal the function of particle binding at the channel entrances for diffusive transport and open the way to a better understanding of membrane transport and design of synthetic membranes with enhanced diffusion rate.

  16. Channel-facilitated diffusion boosted by particle binding at the channel entrance.

    PubMed

    Pagliara, Stefano; Dettmer, Simon L; Keyser, Ulrich F

    2014-07-25

    We investigate single-file diffusion of Brownian particles in arrays of closely confining microchannels permeated by a variety of attractive optical potentials and connecting two baths with equal particle concentration. We simultaneously test free diffusion in the channel, diffusion in optical traps coupled in the center of the channel, and diffusion in traps extending into the baths. We found that both classes of attractive optical potentials enhance the translocation rate through the channel with respect to free diffusion. Surprisingly, for the latter class of potentials we measure a 40-fold enhancement in the translocation rate with respect to free diffusion and find a sublinear power law dependence of the translocation rate on the average number of particles in the channel. Our results reveal the function of particle binding at the channel entrances for diffusive transport and open the way to a better understanding of membrane transport and design of synthetic membranes with enhanced diffusion rate.

  17. The simulation & improved design of tunable channel drop filter using hexagonal photonic crystal ring resonator

    NASA Astrophysics Data System (ADS)

    Chhipa, Mayur Kumar

    2014-10-01

    In this paper, we have proposed a new design of tunable two dimensional (2D) photonic crystal (PhC) channel drop filter (CDF) using ring resonators. The increasing interest in photonic integrated circuits (PIC's) and the increasing use of all-optical fiber networks as backbones for global communication systems have been based in large part on the extremely wide optical transmission bandwidth provided by dielectric materials. Based on the analysis we present novel photonic crystal channel drop filters. Simulations demonstrate that these filters exhibit ideal transfer characteristics. Channel dropping filters (CDF's) that access one channel of a wavelength division multiplexed (WDM) signal while leaving other channels undisturbed are essential components of PIC's and optical communication systems. In this paper we have investigated such parameters which have an effect on resonant wavelength in this Channel Drop Filter, such as dielectric constant of inner, coupling, adjacent and whole rods of the structure. The dimensions of these structures are taken as 20a×19a and the area of the proposed structure is about 125.6μm2; therefore this structure can be used in the future photonic integrated circuits. While using this design the dropping efficiency at the resonance of single ring are 100%. The spectrum of the power transmission is obtained with finite difference time domain (FDTD) method. FDTD method is the most famous method for PhC analysis. In this paper the dielectric rods have a dielectric constant of 10.65, so the refractive index is 3.26 and radius r=0.213a is located in air, where a is a lattice constant. In this we have used five scatter rods for obtaining more coupling efficiency; radius of scatter rods is set to 0.215a. The proposed structure is simulated with OptiFDTD.v.8.0 software, the different dielectric constant of rods equal to ɛr-0.4, ɛr and ɛr+0.4 at wavelength of 1570 nm.

  18. The simulation and improved design of tunable channel drop filter using hexagonal photonic crystal ring resonator

    SciTech Connect

    Chhipa, Mayur Kumar

    2014-10-15

    In this paper, we have proposed a new design of tunable two dimensional (2D) photonic crystal (PhC) channel drop filter (CDF) using ring resonators. The increasing interest in photonic integrated circuits (PIC's) and the increasing use of all-optical fiber networks as backbones for global communication systems have been based in large part on the extremely wide optical transmission bandwidth provided by dielectric materials. Based on the analysis we present novel photonic crystal channel drop filters. Simulations demonstrate that these filters exhibit ideal transfer characteristics. Channel dropping filters (CDF's) that access one channel of a wavelength division multiplexed (WDM) signal while leaving other channels undisturbed are essential components of PIC's and optical communication systems. In this paper we have investigated such parameters which have an effect on resonant wavelength in this Channel Drop Filter, such as dielectric constant of inner, coupling, adjacent and whole rods of the structure. The dimensions of these structures are taken as 20a×19a and the area of the proposed structure is about 125.6μm{sup 2}; therefore this structure can be used in the future photonic integrated circuits. While using this design the dropping efficiency at the resonance of single ring are 100%. The spectrum of the power transmission is obtained with finite difference time domain (FDTD) method. FDTD method is the most famous method for PhC analysis. In this paper the dielectric rods have a dielectric constant of 10.65, so the refractive index is 3.26 and radius r=0.213a is located in air, where a is a lattice constant. In this we have used five scatter rods for obtaining more coupling efficiency; radius of scatter rods is set to 0.215a. The proposed structure is simulated with OptiFDTD.v.8.0 software, the different dielectric constant of rods equal to ε{sub r}−0.4, ε{sub r} and ε{sub r}+0.4 at wavelength of 1570 nm.

  19. Investigations of Particle Velocities in a Slurry Pump Using PIV. Part 1; The Tongue and Adjacent Channel Flow

    NASA Technical Reports Server (NTRS)

    Kadambi, Jaikrishnan R.; Charoenngam, Pathom; Subramanian, Amirthaganesh; Wernet, Mark P.; Sankovic, John M.; Addie, Graeme; Courtwright, Robert

    2004-01-01

    Transport of solid-liquid slurries in pipeline transport over short and medium distances is very important in many industries, including mining related processes. The particle image velocimetry technique was successfully utilized to investigate the velocities and kinetic energy fluctuations of slurry particles at the tongue region of an optically-clear centrifugal pump. The experiments were conducted using 500 micron glass beads at volumetric Concentrations of 2.5% and 5% and at pump speeds of 725 rpm and 1000 rpm. The fluctuation kinetic energy increased approximately 200% to 500% as the pump speed was increased from 725 rpm to IO00 rpm. The directional impingement mechanism is more significant at the pressure side of the blade, tongue and the casing. This mechanism becomes more important as the speed increases. This suggests that the impeller; tongue and the casing of the slurry pump can wear out quickly, especially with an increase in speed. In this paper the emphasis is on the tongue region. The random impingement mechanism caused by the fluctuation kinetic energy of the solids can play an important role on the erosion of the tongue area.

  20. Integrated p-channel MOS gyrator

    NASA Technical Reports Server (NTRS)

    Hochmair, E. S.

    1973-01-01

    Several circuits can be integrated into one chip for applications which require more than one gyrator. They can also be integrated with other p-channel MOS circuits to eliminate need for external connections. Devices can operate at economical low-power levels, because they use FET amplifiers that do not degrade with decreases in supply.

  1. Seismic responses of two adjacent buildings. I. Data and analyses

    USGS Publications Warehouse

    Celebi, Mehmet

    1993-01-01

    In this two-part paper, responses of two, adjacent, seven-story buildings in Norwalk, California, to the Whittier-Narrows, Calif, earthquake of Oct. 1, 1987 are studied. Building A, instrumented according to code recommendations, and building B, extensively instrumented, are offset by 16.3 m from one another. The data set includes motions from the superstructure of both buildings, from a downhole below the foundation of building B, and from three free-field sites. Part I of the paper includes descriptions of the buildings, site, instrumentation, and analysis of the data of each building. System identification and spectral analysis techniques are employed in part I. Building A has identical first-mode frequencies of 0.65 Hz for both building axes. The strong-motion response characteristics of building A are considerably different than those determined from low-amplitude tests. Building B has fundamental modes at 0.76 Hz and 0.83 Hz in the major and minor axes, respectively. Torsional and diaphragm effects in building B are negligible.

  2. Snow Distribution Patterns in Clearings and Adjacent Forest

    NASA Astrophysics Data System (ADS)

    Golding, Douglas L.; Swanson, Robert H.

    1986-12-01

    Snow accumulation patterns were determined for clearings and adjacent forest at Marmot Creek experimental watershed and James River, Alberta. At maximum accumulation snow water equivalent (SWE) was greater in clearings than in forest whether clearings were large, as in 8- to 13-ha blocks where SWE averaged 20% more than in the forest, or small as in the ¼ to 6-H (height) diameter circular clearings where SWE was 13-45% greater than in the forest. SWE was 42 to 52% less in north than in south sectors of 2-6 H clearings. These differences increased with clearing size and time since beginning of accumulation period and are caused by snow ablation (melt and evaporation), a function of direct solar radiation reaching the snowpack. In such situations the snow that has accumulated on the ground cannot be considered a measure of the snow that has actually fallen there. For water balances and hydrologic modeling, snow measurements in partially cleared watersheds must be adjusted for temporal and spatial factors specific to the watershed.

  3. Seismic responses of two adjacent buildings. II. Interaction

    USGS Publications Warehouse

    Celebi, Mehmet

    1993-01-01

    Presented in this part of the two-part paper is a study of the relations between earthquake motions recorded from two, adjacent, seven-story buildings, from a downhole below the foundation of one of the buildings and from three free-field sites, all within one city block. This unique data set was obtained during the Whittier-Narrows, Calif. earthquake of Oct. 1, 1987, Part I includes background information on the two buildings, the site, and the data set. Building response characteristics of a code-type instrumented building (A) and an extensively instrumented building (B) are also studied. In this part, spectral analysis techniques are used to study the relationships between the motions of the roofs and basements, the downhole and the free-field sites. It is asserted that there is building-soil-building interaction between the two buildings at a frequency of 2.35 Hz. Furthermore, the free-field motions are shown to be influenced by the presence of the buildings.

  4. Particulate Matter Levels in Ambient Air Adjacent to Industrial Area

    NASA Astrophysics Data System (ADS)

    Mohamed, R. M. S. R.; Nizam, N. M. S.; Al-Gheethi, A. A.; Lajis, A.; Kassim, A. H. M.

    2016-07-01

    Air quality in the residential areas adjacent to the industrial regions is of great concern due to the association with human health risks. In this work, the concentrations of particulate matter (PM10) in the ambient air of UTHM campus was investigated tostudy the air qualityand their compliance to the Malaysian Ambient Air Quality Guidelines (AAQG). The PM10 samples were taken over 24 hours from the most significant area at UTHM including Stadium, KolejKediamanTunDr. Ismail (KKTDI) and MakmalBahan. The meteorological parameters; temperature, relative humidity, wind speed and wind direction as well as particulate matterwere estimated by using E-Sampler Particulate Matter (PM10) Collector. The highest concentrations of PM10 (55.56 µg/m3) was recorded at MakmalBahan during the working and weekend days. However, these concentrations are less than 150 pg/m3. It can be concluded that although UTHM is surrounded by the industrial area, the air quality in the campus still within the standards limits.

  5. Repeated adjacent-segment degeneration after posterior lumbar interbody fusion.

    PubMed

    Okuda, Shinya; Oda, Takenori; Yamasaki, Ryoji; Maeno, Takafumi; Iwasaki, Motoki

    2014-05-01

    One of the most important sequelae affecting long-term results is adjacent-segment degeneration (ASD) after posterior lumbar interbody fusion (PLIF). Although several reports have described the incidence rate, there have been no reports of repeated ASD. The purpose of this report was to describe 1 case of repeated ASD after PLIF. A 62-year-old woman with L-4 degenerative spondylolisthesis underwent PLIF at L4-5. At the second operation, L3-4 PLIF was performed for L-3 degenerative spondylolisthesis 6 years after the primary operation. At the third operation, L2-3 PLIF was performed for L-2 degenerative spondylolisthesis 1.5 years after the primary operation. Vertebral collapse of L-1 was detected 1 year after the third operation, and the collapse had progressed. At the fourth operation, 3 years after the third operation, vertebral column resection of L-1 and replacement of titanium mesh cages with pedicle screw fixation between T-4 and L-5 was performed. Although the patient's symptoms resolved after each operation, the time between surgeries shortened. The sacral slope decreased gradually although each PLIF achieved local lordosis at the fused segment.

  6. Herbicide interchange between a stream and the adjacent alluvial aquifer

    USGS Publications Warehouse

    Wang, W.; Squillace, P.

    1994-01-01

    Herbicide interchange between a stream and the adjacent alluvial aquifer and quantification of herbicide bank storage during high streamflow were investigated at a research site on the Cedar River flood plain, 10 km southeast of Cedar Rapids, Iowa. During high streamflow in March 1990, alachlor, atrazine, and metolachlor were detected at concentrations above background in water from wells as distant as 20, 50, and 10 m from the river's edge, respectively. During high streamflow in May 1990, alachlor, atrazine, cyanazine, and metolachlor were detected at concentrations above background as distant as 20, 50, 10, and 20 m from the river's edge, respectively. Herbicide bank storage took place during high streamflow when hydraulic gradients were from the river to the alluvial aquifer and the laterally infiltrating river water contained herbicide concentrations larger than background concentrations in the aquifer. The herbicide bank storage can be quantified by multiplying herbicide concentration by the "effective area" that a well represented and an assumed porosity of 0.25. During March 1990, herbicide bank storage values were calculated to be 1.7,79, and 4.0 mg/m for alachlor, atrazine, and metolachlor, respectively. During May 1990, values were 7.1, 54, 11, and 19 mg/m for alachlor, atrazine, cyanazine, and metolachlor, respectively. ?? 1994 American Chemical Society.

  7. Preparation and properties of adjacency crosslinked polyurethane-urea elastomers

    NASA Astrophysics Data System (ADS)

    Wu, Yuan; Cao, Yu-Yang; Wu, Shou-Peng; Li, Zai-Feng

    2012-12-01

    Adjacency crosslinked polyurethane-urea (PUU) elastomers with different crosslinking density were prepared by using hydroxyl-terminated liquid butadiene-nitrile (HTBN), toluene diisocyanate (TDI) and chain extender 3,5-dimethyl thio-toluene diamine (DMTDA) as raw materials, dicumyl peroxide (DCP) as initiator, and N,N'-m-phenylene dimaleimide (HVA-2) as the crosslinking agent. The influences of the crosslinking density and temperature on the structure and properties of such elastomers were investigated. The crosslinking density of PUU elastomer was tested by the NMR method. It is found that when the content of HVA-2 is 1.5%, the mechanical properties of polyurethane elastomer achieve optimal performance. By testing thermal performance of PUU, compared with linear PUU, the thermal stability of the elastomers has a marked improvement. With the addition of HVA-2, the loss factor tan δ decreases. FT-IR spectral studies of PUU elastomer at various temperatures were performed. From this study, heat-resistance polyurethane could be prepared, and the properties of PUU at high temperature could be improved obviously.

  8. The Current Tectonics of the Yukon and Adjacent Area

    NASA Astrophysics Data System (ADS)

    Hyndman, R. D.; Leonard, L. J.

    2014-12-01

    The current tectonics across the Yukon and adjacent areas of western Northwest Territories (NWT) and northern British Columbia appear to be driven primarily by the Yakutat Terrane collision, an "indenter" in the corner of the Gulf of Alaska. GPS data show 1-10 mm/yr northward and eastward, decreasing inland. The rates from earthquake statistics are similar although there are important discrepancies. The eastern Cordillera earthquake mechanisms are mainly thrust in the Mackenzie Mountains of southwestern NWT where the Cordillera upper crust is overthrusting the craton. To the north, the mechanisms are mainly strike-slip in the Richardson Mountains that appear to lie along the edge of the craton. The deformation appears to be limited to the hot and weak Cordillera with the strong craton providing an irregular eastern boundary. For example, there is an eastward bow in the craton edge and the deformation in the Mackenzie Mountains. On the Beaufort Sea margin in the region of the Mackenzie Delta there appears to be a type of "subduction zone" with the continent very slowly overthrusting the oceanic plate, a process that has continued since at least the Cretaceous. A northward moving continental margin block is bounded by left lateral faulting in the west (Canning Displacement Zone of eastern Alaska) and right lateral faulting in the east (Richardson Mountains in eastern Yukon). There is almost no seismicity on this thrust belt but as for some other subduction zones such as Cascadia there is the potential for very infrequent great earthquakes.

  9. Adjacent level spondylodiscitis after anterior cervical decompression and fusion.

    PubMed

    Basu, Saumyajit; Sreeramalingam, Rathinavelu

    2012-05-01

    Postoperative spondylodiscitis after anterior cervical decompression and fusion (ACDF) is rare, but the same occurring at adjacent levels without disturbing the operated level is very rare. We report a case, with 5 year followup, who underwent ACDF from C5 to C7 for cervical spondylotic myelopathy. He showed neurological improvement after surgery but developed discharging sinus after 2 weeks, which healed with antibiotics. He improved on his preoperative symptoms well for the first 2 months. He started developing progressive neck pain and myelopathy after 3 months and investigations revealed spondylodiscitis at C3 and C4 with erosion, collapse, and kyphosis, without any evidence of implant failure or graft rejection at the operated level. He underwent reexploration and implant removal at the operated level (there was good fusion from C5 to C7) followed by debridement/decompression at C3, C4 along with iliac crest bone grafting and stabilization with plate and screws after maximum correction of kyphosis. The biopsy specimen grew Pseudomonas aeruginosa and appropriate sensitive antibiotics (gentamycin and ciprofloxacin) were given for 6 weeks. He was under regular followup for 5 years his myelopathy resolved completely and he is back to work. Complete decompression of the cord and fusion from C2 to C7 was demonstrable on postoperative imaging studies without any evidence of implant loosening or C1/C2 instability at the last followup. PMID:22719127

  10. The Thermomagnetic Instability in Superconducting Films with Adjacent Metal Layer

    NASA Astrophysics Data System (ADS)

    Vestgården, J. I.; Galperin, Y. M.; Johansen, T. H.

    2013-12-01

    Dendritic flux avalanches is a frequently encountered consequence of the thermomagnetic instability in type-II superconducting films. The avalanches, which are potentially harmful for superconductor-based devices, can be suppressed by an adjacent normal metal layer, even when the two layers are not in thermal contact. The suppression of the avalanches in this case is due to so-called magnetic braking, caused by eddy currents generated in the metal layer by propagating magnetic flux. We develop a theory of magnetic braking by analyzing coupled electrodynamics and heat flow in a superconductor-normal metal bilayer. The equations are solved by linearization and by numerical simulation of the avalanche dynamics. We find that in an uncoated superconductor, even a uniform thermomagnetic instability can develop into a dendritic flux avalanche. The mechanism is that a small non-uniformity caused by the electromagnetic non-locality induces a flux-flow hot spot at a random position. The hot spot quickly develops into a finger, which at high speeds penetrates into the superconductor, forming a branching structure. Magnetic braking slows the avalanches, and if the normal metal conductivity is sufficiently high, it can suppress the formation of the dendritic structure. During avalanches, the braking by the normal metal layer prevents the temperature from exceeding the transition temperature of the superconductor. Analytical criteria for the instability threshold are developed using the linear stability analysis. The criteria are found to match quantitatively the instability onsets obtained in simulations.

  11. Macrobenthos of Yenisei Bay and the adjacent Kara Sea shelf

    NASA Astrophysics Data System (ADS)

    Galkin, S. V.; Vedenin, A. A.

    2015-07-01

    Trawl samples were collected in the northern region of Yenisei Bay and adjacent parts of the Kara Sea shelf. A total of eight stations were taken. We found more than 200 species of benthic organisms. A consecutive replacement of benthic communities is observed when going to the north from the Ob and Yenisei estuaries to the open parts of the sea. We could distinguish four different species complexes in the investigated area: a brackish-water complex where Saduria entomon is dominant; an intermediate complex where S. sibirica, S. sabini and Portlandia aestuariorum are dominant; a transitional complex with P. arctica as a dominant species and with a small amount of Ophiocten sericeum; a marine complex where O. sericeum is dominant. When salinity increased, some brackish-water species were replaced by related euryhaline species. One such example was the replacement of brackish-water Saduria entomon isopods by two euryhaline species: S. sibirica and S. sabini. The consecutive replacement of benthic communities showed a break near Sverdrup Island. In this area the marine complex was replaced by a transitional complex with P. arctica.

  12. A linearization of quantum channels

    NASA Astrophysics Data System (ADS)

    Crowder, Tanner

    2015-06-01

    Because the quantum channels form a compact, convex set, we can express any quantum channel as a convex combination of extremal channels. We give a Euclidean representation for the channels whose inverses are also valid channels; these are a subset of the extreme points. They form a compact, connected Lie group, and we calculate its Lie algebra. Lastly, we calculate a maximal torus for the group and provide a constructive approach to decomposing any invertible channel into a product of elementary channels.

  13. Basaltic Lava Channels

    NASA Astrophysics Data System (ADS)

    Cashman, K. V.; Griffiths, R. W.; Kerr, R. C.

    2004-12-01

    In Hawaii, the mode of lava transport - through open channels or through insulating lava tubes - determines the thermal, rheological, and emplacement history of a lava flow. Most Hawaiian lavas are erupted at near-liquidus temperatures and are therefore crystal-poor; lava transport through open channels allows rapid cooling and consequent rapid increases in lava crystallinity. Solidified aa flows resulting from channelized flow are typically fine-grained throughout their thickness, indicating cooling of the entire flow thickness during transport. In contrast, transport of lava through insulating tubes permits flow over long distances with little cooling. Flows emerging from such tubes typically have pahoehoe flow surfaces with glassy crusts. Groundmass textures that coarsen from the flow rind to the interior reflect rates of post-emplacement, rather than syn-emplacement, cooling. To distinguish eruption conditions that result in lava channels from those that allow formation of lava tubes, we have performed a series of laboratory experiments involving injection of PEG 600 (a wax with a Newtonian rheology and freezing temperature of 19ºC) into cold water through both uniform and non-uniform sloping channels. In uniform channels, tube formation can be distinguished from open channel flow using a dimensionless parameter based on a solidification time scale, an advection time scale, and a Rayleigh number that describes convection by heat loss from crust-free shear zones. Theoretical analysis predicts that in the open channel regime, the width of the crust (dc) will vary with the channel width (W) as dc = W5/3. Crustal coverage of non-uniform channels in both laboratory experiments and field examples from Kilauea Volcano, Hawaii, is consistent with this prediction. However, experiments in non-uniform channels illustrate additional controls on the surface coverage of lava channels. Most important is crustal extension resulting from flow acceleration through constrictions

  14. Ion channels in microbes

    PubMed Central

    Martinac, Boris; Saimi, Yoshiro; Kung, Ching

    2008-01-01

    Summary Studies of ion channels have for long been dominated by the animalcentric, if not anthropocentric view of physiology. The structures and activities of ion channels had, however, evolved long before the appearance of complex multicellular organisms on Earth. The diversity of ion channels existing in cellular membranes of prokaryotes is a good example. Though at first it may appear as a paradox that most of what we know about the structure of eukaryotic ion channels is based on the structure of bacterial channels, this should not be surprising given the evolutionary relatedness of all living organisms and suitability of microbial cells for structural studies of biological macromolecules in a laboratory environment. Genome sequences of the human as well as various microbial, plant and animal organisms unambiguously established the evolutionary links, whereas crystallographic studies of the structures of major types of ion channels published over the last decade clearly demonstrated the advantage of using microbes as experimental organisms. The purpose of this review is not only to provide an account of acquired knowledge on microbial ion channels but also to show that the study of microbes and their ion channels may also hold a key to solving unresolved molecular mysteries in the future. PMID:18923187

  15. Valles Marineris and Chryse Outflow Channels

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A color image of Valles Marineris, the great canyon and the south Chryse basin-Valles Marineris outflow channels of Mars; north toward top. The scene shows the entire Valles Marineris canyon system, over 3,000 km long and averaging 8 km deep, extending from Noctis Labyrinthus, the arcuate system of graben to the west, to the chaotic terrain to the east and related outflow canyons that drain toward the Chryse basin. Eos and Capri Chasmata (south to north) are two canyons connected to Valles Marineris. Ganges Chasma lies directly north. The chaos in the southeast part of the image gives rise to several outflow channels, Shalbatana, Simud, Tiu, and Ares Valles (left to right), that drained north into the Chryse basin. The mouth of Ares Valles is the site of the Mars Pathfinder lander.

    This image is a composite of Viking medium-resolution images in black and white and low-resolution images in color; Mercator projection. The image roughly extends from latitude 20 degrees S. to 20 degrees N. and from longitude 15 degrees to 102.5 degrees.

    The connected chasma or valleys of Valles Marineris may have formed from a combination of erosional collapse and structural activity. Layers of material in the eastern canyons might consist of carbonates deposited in ancient lakes, eolian deposits, or volcanic materials. Huge ancient river channels began from Valles Marineris and from adjacent canyons and ran north. Many of the channels flowed north into Chryse Basin.

    The south Chryse outflow channels are cut an average of 1 km into the cratered highland terrain. This terrain is about 9 km above datum near Valles Marineris and steadily decreases in elevation to 1 km below datum in the Chryse basin. Shalbatana is relatively narrow (10 km wide) but can reach 3 km in depth. The channel begins at a 2- to 3-km-deep circular depression within a large impact crater, whose floor is partly covered by chaotic material, and ends in Simud Valles. Tiu and Simud Valles consist of a

  16. High transformer ratio of multi-channel dielectric wakefield structures

    NASA Astrophysics Data System (ADS)

    Shchelkunov, Sergey V.; Marshall, Thomas C.; Sotnikov, Gennadij V.; Hirshfield, Jay L.

    2016-09-01

    Dielectric wakefield (DWA) accelerator concepts are receiving attention on account of their promising performance, mechanical simplicity, and anticipated low cost. Interest in DWA physics directed toward an advanced high-gradient accelerator has been enhanced by a finding that some dielectrics can withstand very high fields (>1 GV/m) for the short times during the passage of charged bunches along dielectric-lined channels. In a two-channel structure, a drive bunch train propagates in a first channel, and in the second adjacent channel where a high gradient wakefield develops, a witness bunch is accelerated. Compared with single-channel DWA's, a two-beam accelerator delivers a high transformer ratio, and thereby reduces the number of drive beam sections needed to achieve a given final test beam energy. An overview of multi-channel DWA structures will be given, with an emphasis on two-channel structures, presenting their advantages and drawbacks, and potential impact on the field. Studies aimed to examine charging rate and charge distribution in a thin walled dielectric wakefield accelerator from a passing charge bunch and the physics of conductivity and discharge phenomena in dielectric materials useful for such accelerator applications are presented in a separate paper in the EAAC-2015 conference proceedings.

  17. 47 CFR 74.786 - Digital channel assignments.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Digital channel assignments. 74.786 Section 74... Translator, and TV Booster Stations § 74.786 Digital channel assignments. (a) An applicant for a new low power television or television translator digital station or for changes in the facilities of...

  18. Generalized channeled polarimetry.

    PubMed

    Alenin, Andrey S; Tyo, J Scott

    2014-05-01

    Channeled polarimeters measure polarization by modulating the measured intensity in order to create polarization-dependent channels that can be demodulated to reveal the desired polarization information. A number of channeled systems have been described in the past, but their proposed designs often unintentionally sacrifice optimality for ease of algebraic reconstruction. To obtain more optimal systems, a generalized treatment of channeled polarimeters is required. This paper describes methods that enable handling of multi-domain modulations and reconstruction of polarization information using linear algebra. We make practical choices regarding use of either Fourier or direct channels to make these methods more immediately useful. Employing the introduced concepts to optimize existing systems often results in superficial system changes, like changing the order, orientation, thickness, or spacing of polarization elements. For the two examples we consider, we were able to reduce noise in the reconstruction to 34.1% and 57.9% of the original design values. PMID:24979633

  19. Athermalized channeled spectropolarimeter enhancement.

    SciTech Connect

    Jones, Julia Craven; Way, Brandyn Michael; Mercier, Jeffrey Alan; Hunt, Jeffery P.

    2013-09-01

    Channeled spectropolarimetry can measure the complete polarization state of light as a function of wavelength. Typically, a channeled spectropolarimeter uses high order retarders made of uniaxial crystal to amplitude modulate the measured spectrum with the spectrally-dependent Stokes polarization information. A primary limitation of conventional channeled spectropolarimeters is related to the thermal variability of the retarders. Thermal variation often forces frequent system recalibration, particularly for field deployed systems. However, implementing thermally stable retarders, made of biaxial crystal, results in an athermal channeled spectropolarimeter that relieves the need for frequent recalibration. This report presents experimental results for an anthermalized channeled spectropolarimeter prototype produced using potassium titanyl phosphate. The results of this prototype are compared to the current thermal stabilization state of the art. Finally, the application of the technique to the thermal infrared is studied, and the athermalization concept is applied to an infrared imaging spectropolarimeter design.

  20. Jamming in Vertical Channels

    NASA Astrophysics Data System (ADS)

    Baxter, G. William; McCausland, Jeffrey; Steel, Fiona

    2010-03-01

    We experimentally study jamming of cylindrical grains in a vertical channel. The grains have a low aspect-ratio (height/diameter < 1) so their shape is like antacid tablets or poker chips. They are allowed to fall through a vertical channel with a square cross section. The channel width is greater than the diameter of a grain and constant throughout the length of the channel with no obstructions or constrictions. It is observed that grains sometimes jam in this apparatus. In a jam, grains form a stable structure from one side of the channel to the other with nothing beneath them. Jams may be strong enough to support additional grains above. The probability of a jam occurring is a function of the grain height and diameter. We will present experimental measurements of the jamming probability in this system and discuss the relationship of these results to other experiments and theories.

  1. Are historical pollution events on the Delaware River recorded as geochemical marker horizons in adjacent marsh sediments

    SciTech Connect

    Walsh, R.; Yemane, K. . Dept. of Geology Bryn Mawr Coll., PA . Geology Dept.)

    1993-03-01

    In the last two hundred years of massive population and industrial growth, the Delaware River has been subjected to several minor and major pollutions. For example, as recently as June 1989 the tanker Presidente Rivera spilled an estimated hundred thousand to million gallons of oil into the river. In the Lower Delaware Basin tides affect the river and its tributaries up to a hundred kilometers inland. The freshwater marshes adjacent to the creeks that empty into the Delaware River experience diurnal tidal sedimentation. It is thus expected that the pollutants in the waterway would be transported via the tidal channels into the adjacent wetlands. The high sedimentation rate, clay-rich sediments, accumulation of terrestrial organic matter, and the low energy environments in these marshes should ensure rapid burial which may preserve some of the contaminants transported into the marshes. To test this hypothesis the authors selected a freshwater marsh along the Raccoon Creek just south of Philadelphia in New Jersey, and collected a 2 m core from a relatively undisturbed portion of the marsh, about 15 m away from the tidal channels. The pH averages around 6.2, ranges from 5.5--6.8, but, is slightly higher in the middle part of the core. The bulk mineralogy comprises chlorite, illite, kaolinite, feldspars and quartz. Vivianite and vermiculite were observed at places lower in the core. Graminae dominates the pollen/spore taxa. The organic debris is unaltered throughout the core. The authors will measure heavy metals and toxic chemicals on < 2[mu]m clay fractions. Also pristane/phytane ratios, indicative of hydrocarbons (crude oils), will be determined on organic matter extracts. The authors will compare and correlate the results to historically documented events of chemical and petroleum spills on the Delaware River.

  2. Hydrogeologic characteristics of the alluvial aquifer and adjacent deposits of the Fountain Creek valley, El Paso County, Colorado

    USGS Publications Warehouse

    Radell, Mary Jo; Lewis, Michael E.; Watts, Kenneth R.

    1994-01-01

    The alluvial aquifer in Fountain Creek Valley between Colorado Springs and Widefield is the source for several public-supply systems. Because of the importance of this aquifer, defining aquifer boundaries, areas where underflow occurs, and where Fountain Creek is hydraulically connected to the aquifer will greatly add to the understanding of the alluvial aquifer and management of the public- supply systems. Bedrock altitude, water-table altitude for October 1991, saturated thickness for October 1991, selected hydrogeologic sections in the alluvial aquifer and adjacent deposits of the Fountain Creek Valley, and estimated underflow rates are mapped or tabulated for the area between Colorado Springs and Widefield, Colorado. Results from test drilling indicate that the bedrock surface is highly irregular and that several ridges and buried channels exist in the study area. These features affect the direction of ground-water flow on a local scale. In places, a shale ridge prevents exchange of water between Fountain Creek and the aquifer. Generally, ground water flowed toward Fountain Creek during the study (June 1991 to September 1992) in response to relatively high hydraulic heads in the aquifer and the steep gradients on the boundaries of the study area. Water levels, which were measured monthly, varied little during the study, except in areas near pumping wells or adjacent to Fountain Creek. Hydraulic-conductivity values, estimated from 30 bail tests in wells completed in the alluvial aquifer, were used to determine underflow across the saturated boundaries of the alluvial aquifer. Estimated hydraulic-conductivity values range from 1 to about 1,300 feet per day; the larger values occur in the buried channel of the alluvial aquifer and the smaller values occur near the boundaries of the saturated alluvium. Estimated underflow into the study area exceeded underflow out of the study area by about 10 times. Gain-loss investigations along Fountain Creek indicated that the

  3. 12. Photocopied August 1978. CHANNELING MACHINES, NOVEMBER 1898. THESE MACHINES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Photocopied August 1978. CHANNELING MACHINES, NOVEMBER 1898. THESE MACHINES BLOCKED OUT SECTIONS IN THE ROCK CUT IN PREPARATION FOR DRILLING AND BLASTING. (17) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

  4. 1. VIEW NORTHWEST, GENERAL VIEW OF GATE, DRAIN CHANNEL AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. VIEW NORTHWEST, GENERAL VIEW OF GATE, DRAIN CHANNEL AND BUILDING SHELTERING GATE OPERATING MECHANISM - Norwich Water Power Company, Canal Drain Gate, West bank of Shetucket River opposite Twelfth Street, Greenville section, Norwich, New London County, CT

  5. The theoretical limits of source and channel coding

    NASA Technical Reports Server (NTRS)

    Dolinar, S. J.; Pollara, F.

    1990-01-01

    The theoretical relationship among signal power, distortion, and bandwidth for several source and channel models is presented. The work is intended as a reference for the evaluation of the performance of specific data compression algorithms.

  6. Tidally influenced alongshore circulation at an inlet-adjacent shoreline

    USGS Publications Warehouse

    Hansen, Jeff E.; Elias, Edwin P.L.; List, Jeffrey H.; Erikson, Li H.; Barnard, Patrick L.

    2013-01-01

    The contribution of tidal forcing to alongshore circulation inside the surfzone is investigated at a 7 km long sandy beach adjacent to a large tidal inlet. Ocean Beach in San Francisco, CA (USA) is onshore of a ∼150 km2 ebb-tidal delta and directly south of the Golden Gate, the sole entrance to San Francisco Bay. Using a coupled flow-wave numerical model, we find that the tides modulate, and in some cases can reverse the direction of, surfzone alongshore flows through two separate mechanisms. First, tidal flow through the inlet results in a barotropic tidal pressure gradient that, when integrated across the surfzone, represents an important contribution to the surfzone alongshore force balance. Even during energetic wave conditions, the tidal pressure gradient can account for more than 30% of the total alongshore pressure gradient (wave and tidal components) and up to 55% during small waves. The wave driven component of the alongshore pressure gradient results from alongshore wave height and corresponding setup gradients induced by refraction over the ebb-tidal delta. Second, wave refraction patterns over the inner shelf are tidally modulated as a result of both tidal water depth changes and strong tidal flows (∼1 m/s), with the effect from currents being larger. These tidally induced changes in wave refraction result in corresponding variability of the alongshore radiation stress and pressure gradients within the surfzone. Our results indicate that tidal contributions to the surfzone force balance can be significant and important in determining the direction and magnitude of alongshore flow.

  7. Seismotectonics of Northeastern United States and adjacent Canada

    SciTech Connect

    Yang, J.; Aggarwal, Y.P.

    1981-06-10

    Data for local earthquakes recorded by a network of stations in northeastern United States and adjacent Canada were analyzed to study the seismicity, the relationship between earthquakes and known faults, the state of stress, and crustal and upper mantle velocity structure. In addition, portable seismographs were deployed in the field to study aftershocks. As a result, accurate locations for about 364 local earthquakes (2< or =m/sub b/< or =5) and 22 focal mechanism solutions were determined. A comparison of the spatial distribution of these events (1970--1979) with historical earthquakes (1534--1959) reveals that seismic activity in the northeast is relatively stationary in space: those areas that have had little or no seismicity historically are relatively aseismic today, whereas the historically active areas are also active today. The instrumental locations, historical seismicity, and focal mechanism solutions show an internal consistency that help us distinguish two distinct seismogenic provinces. (1) The Adirondack-western Quebec province is a northwesterly trending zone of seismic activity, about 200 km wide and at least 500 km long, extending from the SE Adirondacks into western Quebec, Canada. Thrust faulting on planes striking NNW to NW appears to predominate, and the inferred axis of maximum horizontal compression is largely uniform and trends WSW, nearly parallel to the calculated absolute plate motion of North America. Little or no seismicity is found where anorthosite outcrops at the surface. Correlations between gravity anomalies and earthquake locations suggest that seismic activity in this zone is localized to regions of steep NE or SW gradient in Bouguer anomalies. This zone does not appear to extend southeastward to Boston, as proposed by some workers. (2) The Appalachian province is a northeasterly trending zone of seismic activity extending from northern Virginia to New Brunswick, Canada.

  8. Adjacent level disease following lumbar spine surgery: A review

    PubMed Central

    Epstein, Nancy E.

    2015-01-01

    Background: Instrumented lumbar spine surgery is associated with an increased risk of adjacent segment disease (ASD). Multiple studies have explored the various risk factors contributing to ASD that include; fusion length (especially, three or more levels), sagittal malalignment, facet injury, advanced age, and prior cephalad degenerative disease. Methods: In this selective review of ASD, following predominantly instrumented fusions for lumbar degenerative disease, patients typically underwent open versus minimally invasive surgery (MIS), transforaminal lumbar interbody fusions (TLIFs), posterior lumbar interbody fusions (PLIFs), or rarely posterolateral lumbar instrumented or noninstrumented fusions (posterolateral lumbar fusion). Results: The incidence of ASD, following open or MI lumbar instrumented fusions, ranged up to 30%; notably, the addition of instrumentation in different series did not correlate with improved outcomes. Alternatively, in one series, at 164 postoperative months, noninstrumented lumbar fusions reduced the incidence of ASD to 5.6% versus 18.5% for ASD performed with instrumentation. Of interest, dynamic instrumented/stabilization techniques did not protect patients from ASD. Furthermore, in a series of 513 MIS TLIF, there was a 15.6% incidence of perioperative complications that included; a 5.1% frequency of durotomy and a 2.3% instrumentation failure rate. Conclusions: The incidence of postoperative ASD (up to 30%) is greater following either open or MIS instrumented lumbar fusions (e.g., TLIF/PLIF), while decompressions with noninstrumented fusions led to a much smaller 5.6% risk of ASD. Other findings included: MIS instrumented fusions contributed to higher perioperative complication rates, and dynamic stabilization did not protect against ASD. PMID:26693387

  9. Some characteristics of the international space channel

    NASA Technical Reports Server (NTRS)

    Noack, T. L.; Poland, W. B., Jr.

    1975-01-01

    Some physical characteristics of radio transmission links and the technology of PCM modulation combine with the Radio Regulations of the International Telecommunications Union to define a communications channel having a determinable channel capacity, error rate, and sensitivity to interference. These characteristics and the corresponding limitations on EIRP, power flux density, and power spectral density for space service applications are described. The ITU regulations create a critical height of 1027 km where some parameters of the limitation rules change. The nature of restraints on power spectral density are discussed and an approach to a standardized representation of Necessary Bandwidth for the Space Services is described. It is shown that, given the PFD (power flux density) and PSD (power spectral density) limitations of radio regulations, the channel performance is determined by the ratio of effective receiving antenna aperture to system noise temperature. Based on this approach, the method for a quantitative trade-off between spectrum spreading and system performance is presented. Finally, the effects of radio frequency interference between standard systems is analyzed.

  10. Fine Channel Networks

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A color image of fine channel networks on Mars; north toward top. The scene shows heavily cratered highlands dissected by dendritic open channel networks that dissect steep slopes of impact crater walls. This image is a composite of Viking high-resolution images in black and white and low-resolution images in color. The image extends from latitude 9 degrees S. to 5 degrees S. and from longitude 312 degrees to 320 degrees; Mercator projection. The dendritic pattern of the fine channels and their location on steep slopes leads to the interpretation that these are runoff channels. The restriction of these types of channels to ancient highland rocks suggests that these channels are old and date from a time on Mars when conditions existed for precipitation to actively erode rocks. After the channels reach a low plain, they appear to end. Termination may have resulted from burial by younger deposits or perhaps the flows percolated into the surface materials and continued underground.

  11. Why are Channels Sinuous?

    NASA Astrophysics Data System (ADS)

    Constantine, J. A.; Lazarus, E.

    2012-12-01

    Sinuosity is a ubiquitous property of channelized flow patterns on Earth and other planetary bodies. Sinuosity is typically discussed as an emergent consequence of migration processes in meandering rivers, but meandering rivers are only one type of sinuous channel: there are many examples that show little or no indication of meandering, such as bedrock river canyons, drainage channels in tidal mudflats, and volcanic rilles. In some of these patterns, sinuosity is described as "inherited" from a preexisting morphology, which elides an explanation for how the inherited sinuosity originated. Even in river meandering theory there is ongoing debate regarding how initial channel sinuosity arises. Comparing the results of a generalized flow-routing model to observations of natural flow patterns, we find that the ratio of floodplain resistance (R, representing topographic roughness, substrate erodibility, or vegetation density) relative to floodplain slope (m) produces a range of sinuous planforms with natural analogs. We offer a unifying theory for channel sinuosity in which this ratio of resistance to slope (R:m) exerts the primary landscape control on planform shape and predicts the range of sinuosity a floodplain may express. Resistance-dominated floodplains produce channels with higher sinuosity than those of slope-dominated floodplains because increased resistance impedes down-slope flow. Measurement of "relative resistance" (R:m) could inform how riparian restoration projects evaluate the floodplains of artificially straightened rivers. Our analysis suggests that if the sinuosity of a formerly natural channel derived from a high R:m, then even a channel redesigned to be sinuous will straighten if the relative resistance of its floodplain is suppressed or inherently low. (Alternatively, increasing floodplain resistance might foster a higher sinuosity than hydraulic geometry would forecast.) The explanation for sinuosity that we propose is universal enough to account

  12. Dependence of the bit error rate on the signal power and length of a single-channel coherent single-span communication line (100 Gbit s{sup -1}) with polarisation division multiplexing

    SciTech Connect

    Gurkin, N V; Konyshev, V A; Novikov, A G; Treshchikov, V N; Ubaydullaev, R R

    2015-01-31

    We have studied experimentally and using numerical simulations and a phenomenological analytical model the dependences of the bit error rate (BER) on the signal power and length of a coherent single-span communication line with transponders employing polarisation division multiplexing and four-level phase modulation (100 Gbit s{sup -1} DP-QPSK format). In comparing the data of the experiment, numerical simulations and theoretical analysis, we have found two optimal powers: the power at which the BER is minimal and the power at which the fade margin in the line is maximal. We have derived and analysed the dependences of the BER on the optical signal power at the fibre line input and the dependence of the admissible input signal power range for implementation of the communication lines with a length from 30 – 50 km up to a maximum length of 250 km. (optical transmission of information)

  13. Dependence of the bit error rate on the signal power and length of a single-channel coherent single-span communication line (100 Gbit s-1) with polarisation division multiplexing

    NASA Astrophysics Data System (ADS)

    Gurkin, N. V.; Konyshev, V. A.; Nanii, O. E.; Novikov, A. G.; Treshchikov, V. N.; Ubaydullaev, R. R.

    2015-01-01

    We have studied experimentally and using numerical simulations and a phenomenological analytical model the dependences of the bit error rate (BER) on the signal power and length of a coherent single-span communication line with transponders employing polarisation division multiplexing and four-level phase modulation (100 Gbit s-1 DP-QPSK format). In comparing the data of the experiment, numerical simulations and theoretical analysis, we have found two optimal powers: the power at which the BER is minimal and the power at which the fade margin in the line is maximal. We have derived and analysed the dependences of the BER on the optical signal power at the fibre line input and the dependence of the admissible input signal power range for implementation of the communication lines with a length from 30 - 50 km up to a maximum length of 250 km.

  14. Applying alpha-channeling to mirror machines

    SciTech Connect

    Zhmoginov, A. I.; Fisch, N. J.

    2012-05-15

    The {alpha}-channeling effect entails the use of radio-frequency waves to expel and cool high-energetic {alpha} particles born in a fusion reactor; the device reactivity can then be increased even further by redirecting the extracted energy to fuel ions. Originally proposed for tokamaks, this technique has also been shown to benefit open-ended fusion devices. Here, the fundamental theory and practical aspects of {alpha} channeling in mirror machines are reviewed, including the influence of magnetic field inhomogeneity and the effect of a finite wave region on the {alpha}-channeling mechanism. For practical implementation of the {alpha}-channeling effect in mirror geometry, suitable contained weakly damped modes are identified. In addition, the parameter space of candidate waves for implementing the {alpha}-channeling effect can be significantly extended through the introduction of a suitable minority ion species that has the catalytic effect of moderating the transfer of power from the {alpha}-channeling wave to the fuel ions.

  15. Voltage-gated proton channels: what' next?

    PubMed Central

    DeCoursey, Thomas E

    2008-01-01

    This review is an attempt to identify and place in context some of the many questions about voltage-gated proton channels that remain unsolved. As the gene was identified only 2 years ago, the situation is very different than in fields where the gene has been known for decades. For the proton channel, most of the obvious and less obvious structure–function questions are still wide open. Remarkably, the proton channel protein strongly resembles the voltage-sensing domain of many voltage-gated ion channels, and thus offers a novel approach to study gating mechanisms. Another surprise is that the proton channel appears to function as a dimer, with two separate conduction pathways. A number of significant biological questions remain in dispute, unanswered, or in some cases, not yet asked. This latter deficit is ascribable to the intrinsic difficulty in evaluating the importance of one component in a complex system, and in addition, to the lack, until recently, of a means of performing an unambiguous lesion experiment, that is, of selectively eliminating the molecule in question. We still lack a potent, selective pharmacological inhibitor, but the identification of the gene has allowed the development of powerful new tools including proton channel antibodies, siRNA and knockout mice. PMID:18801839

  16. Applying alpha-channeling to mirror machines

    NASA Astrophysics Data System (ADS)

    Zhmoginov, A. I.; Fisch, N. J.

    2012-05-01

    The α-channeling effect entails the use of radio-frequency waves to expel and cool high-energetic α particles born in a fusion reactor; the device reactivity can then be increased even further by redirecting the extracted energy to fuel ions. Originally proposed for tokamaks, this technique has also been shown to benefit open-ended fusion devices. Here, the fundamental theory and practical aspects of α channeling in mirror machines are reviewed, including the influence of magnetic field inhomogeneity and the effect of a finite wave region on the α-channeling mechanism. For practical implementation of the α-channeling effect in mirror geometry, suitable contained weakly damped modes are identified. In addition, the parameter space of candidate waves for implementing the α-channeling effect can be significantly extended through the introduction of a suitable minority ion species that has the catalytic effect of moderating the transfer of power from the α-channeling wave to the fuel ions.

  17. Channel Access in Erlang

    SciTech Connect

    Nicklaus, Dennis J.

    2013-10-13

    We have developed an Erlang language implementation of the Channel Access protocol. Included are low-level functions for encoding and decoding Channel Access protocol network packets as well as higher level functions for monitoring or setting EPICS process variables. This provides access to EPICS process variables for the Fermilab Acnet control system via our Erlang-based front-end architecture without having to interface to C/C++ programs and libraries. Erlang is a functional programming language originally developed for real-time telecommunications applications. Its network programming features and list management functions make it particularly well-suited for the task of managing multiple Channel Access circuits and PV monitors.

  18. Fish communities of a disturbed mangrove wetland and an adjacent tidal river in Palmar, Ecuador

    NASA Astrophysics Data System (ADS)

    Shervette, V. R.; Aguirre, W. E.; Blacio, E.; Cevallos, Rodrigo; Gonzalez, Marcelo; Pozo, Francisco; Gelwick, F.

    2007-03-01

    Coastal Ecuador has lost 20-30% of mangrove wetlands over the past 30 years. Such habitat loss can impair the ecological functions of wetlands. A paucity of information exists concerning mangrove fish communities of Ecuador. In this study we identify the fish community of the remaining mangrove wetland in Palmar, Ecuador. Fish were sampled in the dry season of 2003 and the wet season of 2004 by seining in mangrove creeks and Main channel of Rio Palmar. For comparison, an adjacent tidal river without mangroves, Rio Javita, was also sampled. We collected a total of 12,231 individuals comprising 36 species in 16 families from Rios Palmar and Javita. Gobiidae (7 species) was the most diverse family for mangrove sites followed by Gerreidae (5 species) and Engraulidae (4 species). A total of 34 species were collected in the mangrove wetland, 21 of which were exclusive to the mangroves including three species of juvenile snook (Centropomidae), indicating that the mangrove habitat of Palmar may provide nursery habitat for these economically valued species. In Rio Javita, Carangidae (3 species) was the most diverse family followed by Engraulidae and Gerreidae (2 species each). A total of 14 species were collected in the tidal river, only two of which were exclusive to the river. Multivariate analyses of fish community data indicated significant differences in community composition between the mangrove creeks and the tidal river and between seasons in both. Juvenile white mullet, Mugil curema, were collected in high relative abundance in both Rios Palmar and Javita, as was the tropical silverside Atherinella serrivomer an ecologically important species. Although Rios Palmar and Javita are characterized by relatively low fish species richness compared to other tropical estuarine systems, they appear to provide an important habitat for several economically and ecologically valued species.

  19. Tidal exchange of zooplankton between Lough Hyne and the adjacent coast

    NASA Astrophysics Data System (ADS)

    Rawlinson, K. A.; Davenport, J.; Barnes, D. K. A.

    2005-01-01

    Plankton samples collected in November 2002, February, May and August 2003 were used to examine seasonal variation in tidal exchange of zooplankton biomass, abundance and species composition between Lough Hyne Marine Nature Reserve and the adjacent Atlantic coast. Micro- to mesozooplankton were collected by pump over 24-h sampling periods during spring and neap tides from the narrow channel connecting the semi-enclosed water body to the Atlantic. Sample biomass (dry weight) and total zooplankton abundance peaked in the summer and were lowest in winter, showing a positive relationship with temperature. Zooplankton biomass, total abundance and numbers of holo- and meroplankton revealed import during some diel cycles and export in others. However, the tidal import of these planktonic components was generally dominant, especially during May. The greatest import of numbers of holoplankters and meroplanktonic larvae occurred during May and August, respectively. There was no significant variation in sample biomass between periods of light and dark, but some variation in zooplankton abundance could be explained by this diel periodicity. Significant differences in sample assemblage composition between flood and ebb tide samples were always observed, except during winter neap tides. There was a net import of the copepods Temora longicornis and Oithona helgolandica and the larval stages of Mytilus edulis during spring and summer. Proceraea cornuta and Capitellid trochophores were imported during winter, and a hydrozoan of the genus Obelia during the spring spring tides. Seasonal export from the lough was shown by Pseudopolydora pulchra larvae (autumn and spring), Serpulid trochophores (autumn) and veligers of the bivalve Anomia ephippium (summer). It is suggested that the direction of tidal exchange of meroplanktonic taxa is related to the distribution of the adult populations. Copepod naupliar stages dominated the assemblages except during May spring tides when the copepod

  20. Seasonal variations of transport time of freshwater exchanges between Changjiang Estuary and its adjacent regions

    NASA Astrophysics Data System (ADS)

    Wang, Ya; Shen, Jian; He, Qing; Zhu, Lei; Zhang, Dai

    2015-05-01

    Seasonal variations of transport time of freshwater between the Changjiang Estuary (CJE) and its adjacent regions, Hangzhou Bay (HZB) and Jiangsu Coast (JSC), are investigated. The freshwater exchange between the CJE and HZB is controlled by the strength of the secondary plume, which initiates from the South Passage of the southernmost waterway of CJE. The transport time varies seasonally and is modulated by spring-neap tides. The water exchange between CJE and HZB exhibits a high spatial variation. A large water age is observed in the region near the southern coast of the HZB, which corresponds to high pollutant deposition and low water quality conditions observed in the field. A large exchange occurs in summer between CJE and HZB. The freshwater transported into the HZB is accumulated in the deep channel near the western shoreline of the HZB and weak horizontal exchange occurs in the southern region near the southern shoreline, resulting in an increase of water age in the southern region. Due to the increase of northerly and northwesterly winds in winter and fall, more horizontal exchange occurs, resulting in a decrease of water age. The transport time from Xuliujing to the Hangzhou Bay ranges from 30 to 60 days near Jinshanwei, and ranges from 100 to 140 days in the southern region. The advective transport is the dominant transport mechanism to move water out of the HZB, while shear-induced exchange flow transports freshwater into the HZB. Net flux is out of HZB in winter and fall, but into the HZB in summer when Changjiang discharge is high. A weak transport of freshwater between the CJE and Subei Coast exists. A portion of a freshwater plume transports freshwater northward during summer and fall. It takes approximately 60-140 days for the freshwater from Xuliujing to be transported to the Subei Coast.

  1. Water quality in the lower Puyallup River valley and adjacent uplands, Pierce County, Washington

    USGS Publications Warehouse

    Ebbert, J.C.; Bortleson, Gilbert C.; Fuste, L.A.; Prych, E.A.

    1987-01-01

    The quality of most ground and surface water within and adjacent to the lower Puyallup River valley is suitable for most typical uses; however, some degradation of shallow groundwater quality has occurred. High concentrations of iron and manganese were found in groundwater, sampled at depths of < 40 ft, from wells tapping alluvial aquifers and in a few wells tapping deeper aquifers. Volatile and acid- and base/neutral-extractable organic compounds were not detected in either shallow or deep groundwater samples. The quality of shallow groundwater was generally poorer than that of deep water. Deep ground water (wells set below 100 ft) appears suitable as a supplementary water supply for fish-hatchery needs. Some degradation of water quality, was observed downstream from river mile 1.7 where a municipal wastewater-treatment plant discharges into the river. In the Puyallup River, the highest concentrations of most trace elements were found in bed sediments collected downstream from river mile 1.7. Median concentrations of arsenic, lead, and zinc were higher in bed sediments from small streams compared with those from the Puyallup River, possibly because the small stream drainages, which are almost entirely within developed areas, receive more urban runoff as a percentage of total flow. Total-recoverable trace-element concentrations exceeded water-quality criteria for acute toxicity in the Puyallup River and in some of the small streams. In most cases, high concentrations of total-recoverable trace elements occurred when suspended-sediment concentrations were high. Temperatures in all streams except Wapato Creek and Fife Dutch were within limits (18 C) for Washington State class A water. Minimum dissolved oxygen concentrations were relatively low at 5.6 and 2.0 mg/L, respectively, for Wapato Creek and Fife Dutch. The poorest surface-water quality, which can be characterized as generally unsuitable for fish, was in Fife Dutch, a manmade channel and therefore

  2. Channel patterns: Braided, anabranching, and single-thread

    NASA Astrophysics Data System (ADS)

    Eaton, B. C.; Millar, Robert G.; Davidson, Sarah

    2010-08-01

    A new channel pattern classification is presented based on theoretically derived channel pattern discriminant functions. The thresholds are formulated as power laws that relate the critical slope associated with a change in channel pattern to dimensionless discharge and relative bank strength. One threshold demarcates the boundary between stable single-thread channels (both straight and meandering) and stable multiple-thread channels (anabranching). Another threshold separates anabranching from braided channels, where braided channels are considered to be fundamentally unstable. The exponents of the thresholds are nearly identical to that in the threshold equation originally proposed by Leopold and Wolman (1957), and the coefficients are quite similar as well. An analysis of their data set using our dimensionless approach reveals that no fundamental difference exists between meandering and straight patterns, and thus data from both types are grouped together under the more general heading of single-thread channels. Furthermore, we demonstrate that over a limited range of conditions, an unstable single-thread channel can form stable multiple-threads; but that for systems far from the threshold bounding the single-thread channels, the number of divisions required to produce stable anabranches grows geometrically: this motivates a separation of multiple-thread channels into anabranching and braided types. Our theoretical thresholds are then compared against several large data sets of field data, and the results broadly confirm our proposed thresholds.

  3. Results of en bloc resection for hepatocellular carcinoma extending to adjacent organs

    PubMed Central

    Zhou, Yan-Ming; Sui, Cheng-Jun; Li, Bin; Xu, Feng; Kan, Tong; Yang, Jia-Mei

    2012-01-01

    Background To curatively resect hepatocellular carcinoma (HCC) with adjacent organ extension, the combined resection of these organs is inevitable. We analyzed the safety and effectiveness of en bloc resection for HCC extending to adjacent organs. Methods From December 2002 to May 2006, we compared the surgical outcomes of patients with HCC extending to adjacent organs with those of closely matched, randomly selected patients with HCC without adjacent organ extension. Results We included 42 patients whose HCC extended to adjacent organs and 126 patients whose HCC did not extend to adjacent organs. There was no significant difference in survival, operative morbidity or mortality between the groups. In patients with HCC extending to adjacent organs, histopathological examination of the specimen revealed true tumour invasion in 13 and adhesion in 29 patients. Those with tumour invasion were more likely to have a high incidence of capsule infiltration, microvascular invasion and early intrahepatic recurrence (≤ 1 yr after hepatectomy). The 5-year overall survival of patients with tumour invasion was 11.5%, whereas that of patients with tumour adhesion was 38.1% (p = 0.033). Conclusion En bloc resection is a safe and effective therapy for HCC extending to adjacent organs. Tumour invasion to adjacent organs exhibits a more aggressive clinical behaviour and is associated with worse survival than tumour adhesion. PMID:22617536

  4. [Difference of anti-fracture mechanical characteristics between lateral-root branches and adjacent upper straight roots of four plant species in vigorous growth period].

    PubMed

    Liu, Peng-fei; Liu, Jing; Zhu, Hong-hui; Zhang, Xin; Zhang, Ge; Li, You-fang; Su, Yu; Wang, Chen-jia

    2016-01-01

    Taking four plant species, Caragana korshinskii, Salix psammophila, Hippophae rhamnides and Artemisia sphaerocephala, which were 3-4 years old and in vigorous growth period, as test materials, the anti-fracture forces of lateral-root branches and adjacent upper straight roots were measured with the self-made fixture and the instrument of TY 8000. The lateral-root branches were vital and the diameters were 1-4 mm. The results showed that the anti-fracture force and anti-fracture strength of lateral-root branches were lesser than those of the adjacent upper straight roots even though the average diameter of lateral-root branches was greater. The ratios of anti-fracture strength of lateral-root branches to the adjacent upper straight roots were 71.5% for C. korshinskii, 62.9% for S. psammophila, 45.4% for H. rhamnides and 35.4% for A. sphaerocephala. For the four plants, the anti-fracture force positively correlated with the diameter in a power function, while the anti-fracture strength negatively correlated with diameter in a power function. The anti-fracture strengths of lateral-root branches and adjacent upper straight roots for the four species followed the sequence of C. korshinskii (33.66 and 47.06 MPa) > S. psammophila (17.31 and 27.54 MPa) > H. rhamnides (3.97 and 8.75 MPa) > A. sphaerphala (2.18 and 6.15 MPa).

  5. [Difference of anti-fracture mechanical characteristics between lateral-root branches and adjacent upper straight roots of four plant species in vigorous growth period].

    PubMed

    Liu, Peng-fei; Liu, Jing; Zhu, Hong-hui; Zhang, Xin; Zhang, Ge; Li, You-fang; Su, Yu; Wang, Chen-jia

    2016-01-01

    Taking four plant species, Caragana korshinskii, Salix psammophila, Hippophae rhamnides and Artemisia sphaerocephala, which were 3-4 years old and in vigorous growth period, as test materials, the anti-fracture forces of lateral-root branches and adjacent upper straight roots were measured with the self-made fixture and the instrument of TY 8000. The lateral-root branches were vital and the diameters were 1-4 mm. The results showed that the anti-fracture force and anti-fracture strength of lateral-root branches were lesser than those of the adjacent upper straight roots even though the average diameter of lateral-root branches was greater. The ratios of anti-fracture strength of lateral-root branches to the adjacent upper straight roots were 71.5% for C. korshinskii, 62.9% for S. psammophila, 45.4% for H. rhamnides and 35.4% for A. sphaerocephala. For the four plants, the anti-fracture force positively correlated with the diameter in a power function, while the anti-fracture strength negatively correlated with diameter in a power function. The anti-fracture strengths of lateral-root branches and adjacent upper straight roots for the four species followed the sequence of C. korshinskii (33.66 and 47.06 MPa) > S. psammophila (17.31 and 27.54 MPa) > H. rhamnides (3.97 and 8.75 MPa) > A. sphaerphala (2.18 and 6.15 MPa). PMID:27228590

  6. Mediative adjustment of river dynamics: The role of chute channels in tropical sand-bed meandering rivers

    NASA Astrophysics Data System (ADS)

    Grenfell, M. C.; Nicholas, A. P.; Aalto, R.

    2014-03-01

    This paper examines processes of chute channel formation in four tropical sand-bed meandering rivers; the Strickland and Ok Tedi in Papua New Guinea, the Beni in Bolivia, and the lower Paraguay on the Paraguay/Argentina border. Empirical planform analyses highlight an association between meander bend widening and chute initiation that is consistent with recent physics-based modelling work. GIS analyses indicate that bend widening may be driven by a variety of mechanisms, including scour and cutbank bench formation at sharply-curving bends, point bar erosion due to cutbank impingement against cohesive terrace material, rapid cutbank erosion at rapidly extending bends, and spontaneous mid-channel bar formation. Chute channel initiation is observed to be predominantly associated with two of these widening mechanisms; i) an imbalance between cutbank erosion and point bar deposition associated with rapid bend extension, and ii) bank erosion forced by spontaneous mid-channel bar development. The work extends previous empirical analyses, which highlighted the role of bend extension (elongation) in driving chute initiation, with the observation that the frequency of chute initiation increases once bend extension rates and/or widening ratios exceed a reach-scale threshold. A temporal pattern of increased chute initiation frequency on the Ok Tedi, in response to channel steepening and mid-channel bar development following the addition of mine tailings, mirrors the inter- and intra-reach spatial patterns of chute initiation frequency on the Paraguay, Strickland and Beni Rivers, where increased stream power and sediment load are associated with increased bend extension and chute initiation rates. The process of chute formation is shown to be rate-dependent, and the threshold values of bend extension and widening ratio for chute initiation are shown to scale with measures of river energy, reminiscent of slope-ratio thresholds in river avulsion. Furthermore, Delft3D simulations

  7. Seismotectonics of northeastern United States and adjacent Canada

    NASA Astrophysics Data System (ADS)

    Yang, Jih-Ping; Aggarwal, Yash Pal

    1981-06-01

    Data for local earthquakes recorded by a network of stations in northeastern United States and adjacent Canada were analyzed to study the seismicity, the relationship between earthquakes and known faults, the state of stress, and crustal and upper mantle velocity structure. In addition, portable seismographs were deployed in the field to study aftershocks. As a result, accurate locations for about 364 local earthquakes (2 ≤ mb ≤ 5) and 22 focal mechanism solutions were determined. A comparison of the spatial distribution of these events (1970-1979) with historical earthquakes (1534-1959) reveals that seismic activity in the northeast is relatively stationary in space: those areas that have had little or no seismicity historically are relatively aseismic today, whereas the historically active areas are also active today. The instrumental locations, historical seismicity, and focal mechanism solutions show an internal consistency that help us distinguish two distinct seismogenic provinces. (1) The Adirondack-western Quebec province is a northwesterly trending zone of seismic activity, about 200 km wide and at least 500 km long, extending from the SE Adirondacks into western Quebec, Canada. Thrust faulting on planes striking NNW to NW appears to predominate, and the inferred axis of maximum horizontal compression is largely uniform and trends WSW, nearly parallel to the calculated absolute plate motion of North America. Little or no seismicity is found where anorthosite outcrops at the surface. Correlations between gravity anomalies and earthquake locations suggest that seismic activity in this zone is localized to regions of steep NE or SW gradient in Bouguer anomalies. This zone does not appear to extend southeastward to Boston, as proposed by some workers. (2) The Appalachian province is a northeasterly trending zone of seismic activity extending from northern Virginia to New Brunswick, Canada. Highangle reverse or thrust faulting on N to NE trending planes

  8. Permeation in ion channels: the interplay of structure and theory.

    PubMed

    Miloshevsky, Gennady V; Jordan, Peter C

    2004-06-01

    Combined with high-resolution atomic-level crystal structures of channel forming peptides, theory has become a powerful tool for illuminating factors influencing permeation. Here, advantages and limitations of the more familiar continuum and molecular modeling techniques are briefly outlined. These methods are applied to issues of permeation in two different channel families: gramicidin and K(+) channels. Using structural data, theory provides verifiable atomic-level insights into permeation dynamics, channel conductance and molecular selectivity mechanisms. Not only can theory confirm experimental inference, it can also sometimes provide structural perspectives in advance of experiment.

  9. Calcium Channel Signaling Complexes with Receptors and Channels.

    PubMed

    Zamponi, Gerald W

    2015-01-01

    Voltage-gated calcium channels are not only mediators of cell signalling events, but also are recipients of signalling inputs from G protein coupled receptors (GPCRs) and their associated second messenger pathways. The coupling of GPCRs to calcium channels is optimized through the formation of receptor-channel complexes. In addition, this provides a mechanism for receptorchannel co-trafficking to and from the plasma membrane. On the other hand, voltage-gated calcium channel activity affects other types of ion channels such as voltage-and calcium-activated potassium channels. Coupling efficiency between these two families of channels is also enhanced through the formation of channel-channel complexes. This review provides a concise overview of the current state of knowledge on the physical interactions between voltage-gated calcium channels and members of the GPCR family, and with other types of ion channels.

  10. Channel in Kasei

    NASA Technical Reports Server (NTRS)

    2004-01-01

    14 November 2004 The Kasei Valles are a suite of very large, ancient outflow channels. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of the youngest channel system in the Kasei Valles. Torrents of mud, rocks, and water carved this channel as flow was constricted through a narrow portion of the valley. Layers exposed by the erosion that created the channel can be seen in its walls. This 1.4 meters (5 feet) per pixel image is located near 21.1oN, 72.6oW. The picture covers an area approximately 3 km (1.9 mi) across. Sunlight illuminates the scene from the lower left.

  11. Chondrocyte channel transcriptomics

    PubMed Central

    Lewis, Rebecca; May, Hannah; Mobasheri, Ali; Barrett-Jolley, Richard

    2013-01-01

    To date, a range of ion channels have been identified in chondrocytes using a number of different techniques, predominantly electrophysiological and/or biomolecular; each of these has its advantages and disadvantages. Here we aim to compare and contrast the data available from biophysical and microarray experiments. This letter analyses recent transcriptomics datasets from chondrocytes, accessible from the European Bioinformatics Institute (EBI). We discuss whether such bioinformatic analysis of microarray datasets can potentially accelerate identification and discovery of ion channels in chondrocytes. The ion channels which appear most frequently across these microarray datasets are discussed, along with their possible functions. We discuss whether functional or protein data exist which support the microarray data. A microarray experiment comparing gene expression in osteoarthritis and healthy cartilage is also discussed and we verify the differential expression of 2 of these genes, namely the genes encoding large calcium-activated potassium (BK) and aquaporin channels. PMID:23995703

  12. Proton channel models

    PubMed Central

    Pupo, Amaury; Baez-Nieto, David; Martínez, Agustín; Latorre, Ramón; González, Carlos

    2014-01-01

    Voltage-gated proton channels are integral membrane proteins with the capacity to permeate elementary particles in a voltage and pH dependent manner. These proteins have been found in several species and are involved in various physiological processes. Although their primary topology is known, lack of details regarding their structures in the open conformation has limited analyses toward a deeper understanding of the molecular determinants of their function and regulation. Consequently, the function-structure relationships have been inferred based on homology models. In the present work, we review the existing proton channel models, their assumptions, predictions and the experimental facts that support them. Modeling proton channels is not a trivial task due to the lack of a close homolog template. Hence, there are important differences between published models. This work attempts to critically review existing proton channel models toward the aim of contributing to a better understanding of the structural features of these proteins. PMID:24755912

  13. Calcium channel blocker overdose

    MedlinePlus

    ... Goldschlager N. Cardiovascular toxicology. In: Shannon MW, Borron SW, Burns MJ, eds. Haddad and Winchester's Clinical Management ... SD. Calcium channel antagonists. In: Shannon MW, Borron SW, Burns MJ, eds. Haddad and Winchester's Clinical Management ...

  14. TRP channels in disease.

    PubMed

    Jordt, S E; Ehrlich, B E

    2007-01-01

    The transient receptor potential (TRP) channels are a large family of proteins with six main subfamilies termed the TRPC (canonical), TRPV (vanilloid), TRPM (melastatin), TRPP (polycystin), TRPML (mucolipin), and TRPA (ankyrin) groups. The sheer number of different TRPs with distinct functions supports the statement that these channels are involved in a wide range of processes ranging from sensing of thermal and chemical signals to reloading intracellular stores after responding to an extracellular stimulus. Mutations in TRPs are linked to pathophysiology and specific diseases. An understanding of the role of TRPs in normal physiology is just beginning; the progression from mutations in TRPs to pathophysiology and disease will follow. In this review, we focus on two distinct aspects of TRP channel physiology, the role of TRP channels in intracellular Ca2+ homeostasis, and their role in the transduction of painful stimuli in sensory neurons. PMID:18193640

  15. A Simple Water Channel

    ERIC Educational Resources Information Center

    White, A. S.

    1976-01-01

    Describes a simple water channel, for use with an overhead projector. It is run from a water tap and may be used for flow visualization experiments, including the effect of streamlining and elementary building aerodynamics. (MLH)

  16. Ion Channels in Epithelial Cells

    NASA Astrophysics Data System (ADS)

    Palmer, Lawrence G.

    Ion channels in epithelial cells serve to move ions, and in some cases fluid, between compartments of the body. This function of the transfer of material is fundamentally different from that of the transfer of information, which is the main job of most channels in excitable cells. Nevertheless the basic construction of the channels is similar in many respects in the two tissue types. This chapter reviews the nature of channels in epithelia and discusses how their functions have evolved to accomplish the basic tasks for which they are responsible. I will focus on three channel types: epithelial Na+ channels, inward-rectifier K+ channels, and CFTR Cl- channels.

  17. Channel-tunnels.

    PubMed

    Koronakis, V; Andersen, C; Hughes, C

    2001-08-01

    TolC and its many homologues comprise an alpha-helical transperiplasmic tunnel embedded in the bacterial outer membrane by a contiguous beta-barrel channel, providing a large exit duct for diverse substrates. The 'channel-tunnel' is closed at its periplasmic entrance, but can be opened by an 'iris-like' mechanism when recruited by substrate-engaged proteins in the cytosolic membrane.

  18. Coexistence of continuous variable QKD with intense DWDM classical channels

    NASA Astrophysics Data System (ADS)

    Kumar, Rupesh; Qin, Hao; Alléaume, Romain

    2015-04-01

    We demonstrate experimentally the feasibility of continuous variable quantum key distribution (CV-QKD) in dense-wavelength-division multiplexing networks (DWDM), where QKD will typically have to coexist with several co-propagating (forward or backward) C-band classical channels whose launch power is around 0 dBm. We have conducted experimental tests of the coexistence of CV-QKD multiplexed with an intense classical channel, for different input powers and different DWDM wavelengths. Over a 25 km fiber, a CV-QKD operated over the 1530.12 nm channel can tolerate the noise arising from up to 11.5 dBm classical channel at 1550.12 nm in the forward direction (9.7 dBm in backward). A positive key rate (0.49 kbits s-1) can be obtained at 75 km with classical channel power of respectively -3 and -9 dBm in forward and backward. Based on these measurements, we have also simulated the excess noise and optimized channel allocation for the integration of CV-QKD in some access networks. We have, for example, shown that CV-QKD could coexist with five pairs of channels (with nominal input powers: 2 dBm forward and 1 dBm backward) over a 25 km WDM-PON network. The obtained results demonstrate the outstanding capacity of CV-QKD to coexist with classical signals of realistic intensity in optical networks.

  19. Base of the thumb domain modulates epithelial sodium channel gating.

    PubMed

    Shi, Shujie; Ghosh, D Dipon; Okumura, Sora; Carattino, Marcelo D; Kashlan, Ossama B; Sheng, Shaohu; Kleyman, Thomas R

    2011-04-29

    The activity of the epithelial sodium channel (ENaC) is modulated by multiple external factors, including proteases, cations, anions and shear stress. The resolved crystal structure of acid-sensing ion channel 1 (ASIC1), a structurally related ion channel, and mutagenesis studies suggest that the large extracellular region is involved in recognizing external signals that regulate channel gating. The thumb domain in the extracellular region of ASIC1 has a cylinder-like structure with a loop at its base that is in proximity to the tract connecting the extracellular region to the transmembrane domains. This loop has been proposed to have a role in transmitting proton-induced conformational changes within the extracellular region to the gate. We examined whether loops at the base of the thumb domains within ENaC subunits have a similar role in transmitting conformational changes induced by external Na(+) and shear stress. Mutations at selected sites within this loop in each of the subunits altered channel responses to both external Na(+) and shear stress. The most robust changes were observed at the site adjacent to a conserved Tyr residue. In the context of channels that have a low open probability due to retention of an inhibitory tract, mutations in the loop activated channels in a subunit-specific manner. Our data suggest that this loop has a role in modulating channel gating in response to external stimuli, and are consistent with the hypothesis that external signals trigger movements within the extracellular regions of ENaC subunits that are transmitted to the channel gate. PMID:21367859

  20. Kv Channel S1-S2 Linker Working as a Binding Site of Human β-Defensin 2 for Channel Activation Modulation.

    PubMed

    Feng, Jing; Yang, Weishan; Xie, Zili; Xiang, Fang; Cao, Zhijian; Li, Wenxin; Hu, Hongzhen; Chen, Zongyun; Wu, Yingliang

    2015-06-19

    Among the three extracellular domains of the tetrameric voltage-gated K(+) (Kv) channels consisting of six membrane-spanning helical segments named S1-S6, the functional role of the S1-S2 linker still remains unclear because of the lack of a peptide ligand. In this study, the Kv1.3 channel S1-S2 linker was reported as a novel receptor site for human β-defensin 2 (hBD2). hBD2 shifts the conductance-voltage relationship curve of the human Kv1.3 channel in a positive direction by nearly 10.5 mV and increases the activation time constant for the channel. Unlike classical gating modifiers of toxin peptides from animal venoms, which generally bind to the Kv channel S3-S4 linker, hBD2 only targets residues in both the N and C termini of the S1-S2 linker to influence channel gating and inhibit channel currents. The increment and decrement of the basic residue number in a positively charged S4 sensor of Kv1.3 channel yields conductance-voltage relationship curves in the positive direction by ∼31.2 mV and 2-4 mV, which suggests that positively charged hBD2 is anchored in the channel S1-S2 linker and is modulating channel activation through electrostatic repulsion with an adjacent S4 helix. Together, these findings reveal a novel peptide ligand that binds with the Kv channel S1-S2 linker to modulate channel activation. These findings also highlight the functional importance of the Kv channel S1-S2 linker in ligand recognition and modification of channel activation.

  1. Electronic Power Switch for Fault-Tolerant Networks

    NASA Technical Reports Server (NTRS)

    Volp, J.

    1987-01-01

    Power field-effect transistors reduce energy waste and simplify interconnections. Current switch containing power field-effect transistor (PFET) placed in series with each load in fault-tolerant power-distribution system. If system includes several loads and supplies, switches placed in series with adjacent loads and supplies. System of switches protects against overloads and losses of individual power sources.

  2. Late Pleistocene channel-levee development on Monterey submarine fan, central California

    USGS Publications Warehouse

    Normark, W.R.

    1999-01-01

    Much of the modern upper (proximal) Monterey fan is a channel-levee complex, the Upper Turbidite Sequence (UTS), that was deeply eroded after the channel breached a volcanic ridge to reach a deeper base level. Ages of sediment samples collected with the ALVIN submersible from the deepest outcrop within the channel-levee system, 390 m below the adjacent western levee crest, indicate that the UTS deposits accumulated at ???1 m ka-1 during the last 500 ka. Neogene and Early Pleistocene sediment accumulation on the fan prior to the UTS was much slower (<0.03 m ka-1), and underlying turbidite systems(?) had substantially different morphologic expression(s).

  3. Integrated microchip incorporating atomic magnetometer and microfluidic channel for NMR and MRI

    DOEpatents

    Ledbetter, Micah P.; Savukov, Igor M.; Budker, Dmitry; Shah, Vishal K.; Knappe, Svenja; Kitching, John; Michalak, David J.; Xu, Shoujun; Pines, Alexander

    2011-08-09

    An integral microfluidic device includes an alkali vapor cell and microfluidic channel, which can be used to detect magnetism for nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI). Small magnetic fields in the vicinity of the vapor cell can be measured by optically polarizing and probing the spin precession in the small magnetic field. This can then be used to detect the magnetic field of in encoded analyte in the adjacent microfluidic channel. The magnetism in the microfluidic channel can be modulated by applying an appropriate series of radio or audio frequency pulses upstream from the microfluidic chip (the remote detection modality) to yield a sensitive means of detecting NMR and MRI.

  4. Charge Fluctuations and Boundary Conditions of Biological Ion Channels: Effect on the Ionic Transition Rate

    NASA Astrophysics Data System (ADS)

    Tindjong, R.; Luchinsky, D. G.; McClintock, P. V. E.; Kaufman, I.; Eisenberg, R. S.

    2009-04-01

    A self-consistent solution is derived for the Poisson-Nernst-Planck (PNP) equation, valid both inside a biological ion channel and in the adjacent bulk fluid. An iterative procedure is used to match the two solutions together at the channel mouth. Charge fluctuations at the mouth are modeled as shot noise flipping the height of the potential barrier at the selectivity site. The resultant estimates of the conductivity of the ion channel are in good agreement with Gramicidin experimental measurements and they reproduce the observed current saturation with increasing concentration.

  5. Charge Fluctuations and Boundary Conditions of Biological Ion Channels: Effect on the Ionic Transition Rate

    SciTech Connect

    Tindjong, R.; McClintock, P. V. E.; Luchinsky, D. G.; Kaufman, I.; Eisenberg, R. S.

    2009-04-23

    A self-consistent solution is derived for the Poisson-Nernst-Planck (PNP) equation, valid both inside a biological ion channel and in the adjacent bulk fluid. An iterative procedure is used to match the two solutions together at the channel mouth. Charge fluctuations at the mouth are modeled as shot noise flipping the height of the potential barrier at the selectivity site. The resultant estimates of the conductivity of the ion channel are in good agreement with Gramicidin experimental measurements and they reproduce the observed current saturation with increasing concentration.

  6. A 6 μW per channel analog biomimetic cochlear implant processor filterbank architecture with across channels AGC.

    PubMed

    Yang, Guang; Lyon, Richard F; Drakakis, Emmanuel M

    2015-02-01

    A new analog cochlear implant processor filterbank architecture of increased biofidelity, enhanced across-channel contrast and very low power consumption has been designed and prototyped. Each channel implements a biomimetic, asymmetric bandpass-like One-Zero-Gammatone-Filter (OZGF) transfer function, using class-AB log-domain techniques. Each channel's quality factor and suppression are controlled by means of a new low power Automatic Gain Control (AGC) scheme which is coupled across the neighboring channels and emulates lateral inhibition (LI) phenomena in the auditory system. Detailed measurements from a five-channel silicon IC prototype fabricated in a 0.35 μm AMS technology confirm the operation of the coupled AGC scheme and its ability to enhance contrast among channel outputs. The prototype is characterized by an input dynamic range of 92 dB while consuming only 28 μW of power in total ( ∼ 6 μW per channel) under a 1.8 V power supply. The architecture is well-suited for fully-implantable cochlear implants.

  7. LED lamp power management system and method

    DOEpatents

    Gaines, James; Clauberg, Bernd; Van Erp, Josephus A. M.

    2013-03-19

    An LED lamp power management system and method including an LED lamp having an LED controller 58; a plurality of LED channels 60 operably connected to the LED controller 58, each of the plurality of LED channels 60 having a channel switch 62 in series with at least one shunted LED circuit 83, the shunted LED circuit 83 having a shunt switch 68 in parallel with an LED source 80. The LED controller 58 reduces power loss in one of the channel switch 62 and the shunt switch 68 when LED lamp electronics power loss (P.sub.loss) exceeds an LED lamp electronics power loss limit (P.sub.lim); and each of the channel switches 62 receives a channel switch control signal 63 from the LED controller 58 and each of the shunt switches 68 receives a shunt switch control signal 69 from the LED controller 58.

  8. Morphodynamics of Floodplain Chute Channels

    NASA Astrophysics Data System (ADS)

    David, S. R.; Edmonds, D. A.

    2015-12-01

    Floodplain chute channel formation is a key process that can enable rivers to transition from single-thread to multi-thread planform geometries. Floodplain chute channels are usually incisional channels connecting topographic lows across point bars and in the floodplain. Surprisingly, it is still not clear what conditions promote chute channel formation and what governs their morphodynamic behavior. Towards this end we have initiated an empirical and theoretical study of floodplain chute channels in Indiana, USA. Using elevation models and satellite imagery we mapped 3064 km2 of floodplain in Indiana, and find that 37.3% of mapped floodplains in Indiana have extensive chute channel networks. These chute channel networks consist of two types of channel segments: meander cutoffs of the main channel and chute channels linking the cutoffs together. To understand how these chute channels link meander cutoffs together and eventually create floodplain channel networks we use Delft3D to explore floodplain morphodynamics. Our first modeling experiment starts from a generic floodplain prepopulated with meander cutoffs to test under what conditions chute channels form.We find that chute channel formation is optimized at an intermediate flood discharge. If the flood discharge is too large the meander cutoffs erosively diffuse, whereas if the floodwave is too small the cutoffs fill with sediment. A moderately sized floodwave reworks the sediment surrounding the topographic lows, enhancing the development of floodplain chute channels. Our second modeling experiments explore how floodplain chute channels evolve on the West Fork of the White River, Indiana, USA. We find that the floodplain chute channels are capable of conveying the entire 10 yr floodwave (Q=1330m3/s) leaving the inter-channel areas dry. Moreover, the chute channels can incise into the floodplain while the margins of channels are aggrading, creating levees. Our results suggest that under the right conditions

  9. 33 CFR 162.215 - Lake Tahoe, Nev.; restricted area adjacent to Nevada Beach.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Lake Tahoe, Nev.; restricted area adjacent to Nevada Beach. 162.215 Section 162.215 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... § 162.215 Lake Tahoe, Nev.; restricted area adjacent to Nevada Beach. (a) The restricted area....

  10. 33 CFR 162.215 - Lake Tahoe, Nev.; restricted area adjacent to Nevada Beach.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Lake Tahoe, Nev.; restricted area adjacent to Nevada Beach. 162.215 Section 162.215 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... § 162.215 Lake Tahoe, Nev.; restricted area adjacent to Nevada Beach. (a) The restricted area....

  11. 33 CFR 162.215 - Lake Tahoe, Nev.; restricted area adjacent to Nevada Beach.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Lake Tahoe, Nev.; restricted area adjacent to Nevada Beach. 162.215 Section 162.215 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... § 162.215 Lake Tahoe, Nev.; restricted area adjacent to Nevada Beach. (a) The restricted area....

  12. 33 CFR 162.215 - Lake Tahoe, Nev.; restricted area adjacent to Nevada Beach.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Lake Tahoe, Nev.; restricted area adjacent to Nevada Beach. 162.215 Section 162.215 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... § 162.215 Lake Tahoe, Nev.; restricted area adjacent to Nevada Beach. (a) The restricted area....

  13. 33 CFR 162.215 - Lake Tahoe, Nev.; restricted area adjacent to Nevada Beach.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Lake Tahoe, Nev.; restricted area adjacent to Nevada Beach. 162.215 Section 162.215 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... § 162.215 Lake Tahoe, Nev.; restricted area adjacent to Nevada Beach. (a) The restricted area....

  14. 30 CFR 282.6 - Disclosure of data and information to an adjacent State.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 2 2011-07-01 2011-07-01 false Disclosure of data and information to an adjacent State. 282.6 Section 282.6 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND... THAN OIL, GAS, AND SULPHUR General § 282.6 Disclosure of data and information to an adjacent State....

  15. Large subarticular cysts (geodes) adjacent to the knee-joint in rheumatoid arthritis.

    PubMed

    Carter, A R; Liyanage, S P

    1975-10-01

    Two patients with rheumatoid arthritis are described, who developed very large bone cysts or geodes adjacent to the knee-joint. The existence of cysts adjacent to joints involved by rheumatoid arthritis is well recognised, but the occurrence of very large cysts is unusual and may present diagnostic difficulties. Possible aetiological factors are discussed.

  16. Learning at a Distance: I. Statistical Learning of Non-Adjacent Dependencies

    ERIC Educational Resources Information Center

    Newport, Elissa L.; Aslin, Richard N.

    2004-01-01

    In earlier work we have shown that adults, young children, and infants are capable of computing transitional probabilities among adjacent syllables in rapidly presented streams of speech, and of using these statistics to group adjacent syllables into word-like units. In the present experiments we ask whether adult learners are also capable of such…

  17. 33 CFR 110.140 - Buzzards Bay, Nantucket Sound, and adjacent waters, Mass.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Buzzards Bay, Nantucket Sound, and adjacent waters, Mass. 110.140 Section 110.140 Navigation and Navigable Waters COAST GUARD..., Nantucket Sound, and adjacent waters, Mass. (a) New Bedford Outer Harbor—(1) Anchorage A. West of...

  18. 33 CFR 165.1303 - Puget Sound and adjacent waters, WA-regulated navigation area.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Puget Sound and adjacent waters... § 165.1303 Puget Sound and adjacent waters, WA—regulated navigation area. (a) The following is a... Light to New Dungeness Light and all points in the Puget Sound area north and south of these lights....

  19. 33 CFR 165.1303 - Puget Sound and adjacent waters, WA-regulated navigation area.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Puget Sound and adjacent waters... § 165.1303 Puget Sound and adjacent waters, WA—regulated navigation area. (a) The following is a... Light to New Dungeness Light and all points in the Puget Sound area north and south of these lights....

  20. 33 CFR 165.1303 - Puget Sound and adjacent waters, WA-regulated navigation area.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Puget Sound and adjacent waters... § 165.1303 Puget Sound and adjacent waters, WA—regulated navigation area. (a) The following is a... Light to New Dungeness Light and all points in the Puget Sound area north and south of these lights....

  1. 33 CFR 165.1303 - Puget Sound and adjacent waters, WA-regulated navigation area.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Puget Sound and adjacent waters... § 165.1303 Puget Sound and adjacent waters, WA—regulated navigation area. (a) The following is a... Light to New Dungeness Light and all points in the Puget Sound area north and south of these lights....

  2. 33 CFR 165.1303 - Puget Sound and adjacent waters, WA-regulated navigation area.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Puget Sound and adjacent waters... § 165.1303 Puget Sound and adjacent waters, WA—regulated navigation area. (a) The following is a... Light to New Dungeness Light and all points in the Puget Sound area north and south of these lights....

  3. Precipitation patterns during channel flow

    NASA Astrophysics Data System (ADS)

    Jamtveit, B.; Hawkins, C.; Benning, L. G.; Meier, D.; Hammer, O.; Angheluta, L.

    2013-12-01

    Mineral precipitation during channelized fluid flow is widespread in a wide variety of geological systems. It is also a common and costly phenomenon in many industrial processes that involve fluid flow in pipelines. It is often referred to as scale formation and encountered in a large number of industries, including paper production, chemical manufacturing, cement operations, food processing, as well as non-renewable (i.e. oil and gas) and renewable (i.e. geothermal) energy production. We have studied the incipient stages of growth of amorphous silica on steel plates emplaced into the central areas of the ca. 1 meter in diameter sized pipelines used at the hydrothermal power plant at Hellisheidi, Iceland (with a capacity of ca 300 MW electricity and 100 MW hot water). Silica precipitation takes place over a period of ca. 2 months at approximately 120°C and a flow rate around 1 m/s. The growth produces asymmetric ca. 1mm high dendritic structures ';leaning' towards the incoming fluid flow. A novel phase-field model combined with the lattice Boltzmann method is introduced to study how the growth morphologies vary under different hydrodynamic conditions, including non-laminar systems with turbulent mixing. The model accurately predicts the observed morphologies and is directly relevant for understanding the more general problem of precipitation influenced by turbulent mixing during flow in channels with rough walls and even for porous flow. Reference: Hawkins, C., Angheluta, L., Hammer, Ø., and Jamtveit, B., Precipitation dendrites in channel flow. Europhysics Letters, 102, 54001

  4. Assessment of heavy metal levels in surface sediments of estuaries and adjacent coastal areas in China

    NASA Astrophysics Data System (ADS)

    Liu, Xianbin; Li, Deliang; Song, Guisheng

    2016-05-01

    This article investigates the variations of contamination levels of heavy metals such as copper, lead, chromium, cadmium, zinc, arsenic, and mercury over time in surface sediments of the Changjiang River Estuary (CRE), Yellow River Estuary (YRE), Pearl River Estuary (PRE), and their adjacent coastal areas in China. The contamination factor (CF), pollution load index (PLI), and geoaccumulation index (I geo) are used to evaluate the quality of the surface sediments in the study areas. The results showed that the CRE, YRE, and their adjacent coastal areas were at a low risk of contamination in terms of heavy metals, while the PRE and its adjacent coastal area were at a moderate level. By comparison, the concentrations of heavy metals in the surface sediments of the YRE and its adjacent coastal area were relatively lower than those in the CRE, PRE, and their adjacent coastal areas.

  5. Structural and Dynamic Mechanisms for the Function and Inhibition of the M2 Proton Channel From Influenza A Virus

    PubMed Central

    Wang, Jun; Qiu, Jade Xiaoyan; Soto, Cinque; DeGrado, William F.

    2011-01-01

    The M2 proton channel from influenza A virus, a prototype for a class of viral ion channels known as viroporins, conducts protons along a chain of water molecules and ionizable side chains, including His37. Recent studies highlight a delicate interplay between protein folding, proton binding and proton conduction through the channel. Drugs inhibit proton conduction by binding to an aqueous cavity adjacent to M2’s proton-selective filter, thereby blocking access of proton to the filter, and altering the energetic landscape of the channel and the energetics of proton-binding to His37. PMID:21247754

  6. A CAFE Delta Building Model With Channel Networks

    NASA Astrophysics Data System (ADS)

    Liang, M.; Voller, V. R.; Paola, C.; Edmonds, D.

    2009-12-01

    Mass balance sediment transport models based on the Exner equation are excellent at predicting the overall growth of river deltas, such as the position of the shoreline or the total area of delta as a function of time. The detailed evolution of delta growth, however, is dependent on the structure of the channel network which distributes the sediments. For example, vegetation dynamics along channel edges plays an important role in land building process. Therefore, to fully resolve the key delta growth processes, models must be able to evolve and track the channels on its surface. Current attempts to resolve channel networks in delta building models cover a wide range of scales. At small scales, solvers that resolve the three-dimensional flow field successfully simulate the formation of river mouth bar and channel bifurcation, but due to their computational demand they cannot be used to model a whole delta. At large scales, two-dimensional cellular models can crudely incorporate self-channelization but do not resolve the full channel network. In the middle, the coupling of Cellular Automata rules for channel evolution with Finite Element models of sediment transport (CAFE models) shows promise of providing physically and computationally feasible models. Here we borrow recent ideas from diffusion models of dendritic crystal structures, to develop a CAFE delta building model. We use an unstructured mesh of Delaunay triangulation with vertex nodes and two sets of rules are introduced as “building” and “aging” rules. Building rules describe the diffusional flux between adjacent nodes, essentially equivalent to a discrete solution of the PDE system describing diffusion of sediment in a fluvial delta. Channels are developed by selecting nodes in which sediment flux exceeds a given threshold. Interestingly bifurcations emerge at the shoreline, even though no rules specify their creation. Aging rules are applied to the cellular structure of channel networks to

  7. Organellar Channels and Transporters

    PubMed Central

    Xu, Haoxing; Martinoia, Enrico; Szabo, Ildiko

    2015-01-01

    Decades of intensive research has led to the discovery of most plasma membrane ion channels and transporters and the characterization of their physiological functions. In contrast, although over 80% of transport processes occur inside the cells, the ion flux mechanisms across intracellular membranes (the endoplasmic reticulum, Golgi apparatus, endosomes, lysosomes, mitochondria, chloroplasts, and vacuoles) are difficult to investigate and remain poorly understood. Recent technical advances in super-resolution microscopy, organellar electrophysiology, organelle-targeted fluorescence imaging, and organelle proteomics have pushed a large step forward in the research of intracellular ion transport. Many new organellar channels are molecularly identified and electrophysiologically characterized. Additionally, molecular identification of many of these ion channels/transporters has made it possible to study their physiological functions by genetic and pharmacological means. For example, organellar channels have been shown to regulate important cellular processes such as programmed cell death and photosynthesis, and are involved in many different pathologies. This Special Issue (SI) on Organellar Channels and Transporters aims to provide a forum to discuss the recent advances and to define the standard and open questions in this exciting and rapidly-developing field. Along this line, a new Gordon Research Conference dedicated to the multidisciplinary study of intracellular membrane transport proteins will be launched this coming summer. PMID:25795199

  8. TRP Channels and Analgesia

    PubMed Central

    Premkumar, Louis S.; Abooj, Mruvil

    2013-01-01

    Since cloning and characterizing the first nociceptive ion channel Transient Receptor Potential (TRP) Vanilloid 1 (TRPV1), other TRP channels involved in nociception have been cloned and characterized, which include TRP Vanilloid 2 (TRPV2), TRP Vanilloid 3 (TRPV3), TRP Vanilloid 4 (TRPV4), TRP Ankyrin 1 (TRPA1) and TRP Melastatin 8 (TRPM8), more recently TRP Canonical 1, 5, 6 (TRPC1, 5, 6), TRP Melastatin 2 (TRPM2) and TRP Melastatin 3 (TRPM3). These channels are predominantly expressed in C and Aδ nociceptors and transmit noxious thermal, mechanical and chemical sensitivities. TRP channels are modulated by pro-inflammatory mediators, neuropeptides and cytokines. Significant advances have been made targeting these receptors either by antagonists or agonists to treat painful conditions. In this review, we will discuss TRP channels as targets for next generation analgesics and the side effects that may ensue as a result of blocking/activating these receptors, because they are also involved in physiological functions such as release of vasoactive neuropeptides and regulation of vascular tone, maintenance of the body temperature, gastrointestinal motility, urinary bladder control etc. PMID:22910182

  9. MEMS in microfluidic channels.

    SciTech Connect

    Ashby, Carol Iris Hill; Okandan, Murat; Michalske, Terry A.; Sounart, Thomas L.; Matzke, Carolyn M.

    2004-03-01

    Microelectromechanical systems (MEMS) comprise a new class of devices that include various forms of sensors and actuators. Recent studies have shown that microscale cantilever structures are able to detect a wide range of chemicals, biomolecules or even single bacterial cells. In this approach, cantilever deflection replaces optical fluorescence detection thereby eliminating complex chemical tagging steps that are difficult to achieve with chip-based architectures. A key challenge to utilizing this new detection scheme is the incorporation of functionalized MEMS structures within complex microfluidic channel architectures. The ability to accomplish this integration is currently limited by the processing approaches used to seal lids on pre-etched microfluidic channels. This report describes Sandia's first construction of MEMS instrumented microfluidic chips, which were fabricated by combining our leading capabilities in MEMS processing with our low-temperature photolithographic method for fabricating microfluidic channels. We have explored in-situ cantilevers and other similar passive MEMS devices as a new approach to directly sense fluid transport, and have successfully monitored local flow rates and viscosities within microfluidic channels. Actuated MEMS structures have also been incorporated into microfluidic channels, and the electrical requirements for actuation in liquids have been quantified with an elegant theory. Electrostatic actuation in water has been accomplished, and a novel technique for monitoring local electrical conductivities has been invented.

  10. Channel Identification Machines

    PubMed Central

    Lazar, Aurel A.; Slutskiy, Yevgeniy B.

    2012-01-01

    We present a formal methodology for identifying a channel in a system consisting of a communication channel in cascade with an asynchronous sampler. The channel is modeled as a multidimensional filter, while models of asynchronous samplers are taken from neuroscience and communications and include integrate-and-fire neurons, asynchronous sigma/delta modulators and general oscillators in cascade with zero-crossing detectors. We devise channel identification algorithms that recover a projection of the filter(s) onto a space of input signals loss-free for both scalar and vector-valued test signals. The test signals are modeled as elements of a reproducing kernel Hilbert space (RKHS) with a Dirichlet kernel. Under appropriate limiting conditions on the bandwidth and the order of the test signal space, the filter projection converges to the impulse response of the filter. We show that our results hold for a wide class of RKHSs, including the space of finite-energy bandlimited signals. We also extend our channel identification results to noisy circuits. PMID:23227035

  11. Sound radiation in turbulent channel flows

    NASA Astrophysics Data System (ADS)

    Hu, Zhiwei; Morfey, Christopher L.; Sandham, Neil D.

    2003-01-01

    Lighthill’s acoustic analogy is formulated for turbulent channel flow with pressure as the acoustic variable, and integrated over the channel width to produce a two-dimensional inhomogeneous wave equation. The equivalent sources consist of a dipole distribution related to the sum of the viscous shear stresses on the two walls, together with monopole and quadrupole distributions related to the unsteady turbulent dissipation and Reynolds stresses respectively. Using a rigid-boundary Green function, an expression is found for the power spectrum of the far-field pressure radiated per unit channel area. Direct numerical simulations (DNS) of turbulent plane Poiseuille and Couette flow have been performed in large computational domains in order to obtain good resolution of the low-wavenumber source behaviour. Analysis of the DNS databases for all sound radiation sources shows that their wavenumber frequency spectra have non-zero limits at low wavenumber. The sound power per unit channel area radiated by the dipole distribution is proportional to Mach number squared, while the monopole and quadrupole contributions are proportional to the fourth power of Mach number. Below a particular Mach number determined by the frequency and radiation direction, the dipole radiation due to the wall shear stress dominates the far field. The quadrupole takes over at Mach numbers above about 0.1, while the monopole is always the smallest term. The resultant acoustic field at any point in the channel consists of a statistically diffuse assembly of plane waves, with spectrum limited by damping to a value that is independent of Mach number in the low-M limit.

  12. Water and sediment transport of channel-flat systems in a mesotidal mudflat: Willapa Bay, Washington

    NASA Astrophysics Data System (ADS)

    Nowacki, Daniel J.; Ogston, Andrea S.

    2013-06-01

    The muddy tidal flats of southern Willapa Bay, Washington are tidally dominated and receive little direct freshwater input. We use data from instruments deployed in channels of different size and on their adjacent flats to investigate the hydrodynamics and sediment dynamics of each morphological setting under a range of seasonal and meteorological conditions, including rain and wind events. Interaction between the morphology of the channel/flat complex and tidal water-level variations produces well-defined velocity pulses during both flooding and ebbing tides. These pulses represent about 27% of the total along-channel water transport and 35% of the suspended-sediment transport of the system. Maintenance of continuity produces the velocity pulse, and pulse magnitude is determined by tidal range. Wind alters the flow regime in channels and on the flat, enhancing over-flat ebb flow in this study location while decreasing ebb-pulse intensity. Wind speed was positively correlated with minimum suspended-sediment concentration. Precipitation falling directly on flats was found to erode flat sediment, which subsequently formed a temporary deposit in the adjacent channel. Residual along-channel water transport in channels and on nearby flats was flood dominant under all seasonal conditions sampled, and sediment flux was flood dominant during winter and spring deployments.

  13. Quantum steganography with noisy quantum channels

    NASA Astrophysics Data System (ADS)

    Shaw, Bilal A.; Brun, Todd A.

    2011-02-01

    Steganography is the technique of hiding secret information by embedding it in a seemingly “innocent” message. We present protocols for hiding quantum information by disguising it as noise in a codeword of a quantum error-correcting code. The sender (Alice) swaps quantum information into the codeword and applies a random choice of unitary operation, drawing on a secret random key she shares with the receiver (Bob). Using the key, Bob can retrieve the information, but an eavesdropper (Eve) with the power to monitor the channel, but without the secret key, cannot distinguish the message from channel noise. We consider two types of protocols: one in which the hidden quantum information is stored locally in the codeword, and another in which it is embedded in the space of error syndromes. We analyze how difficult it is for Eve to detect the presence of secret messages, and estimate rates of steganographic communication and secret key consumption for specific protocols and examples of error channels. We consider both the case where there is no actual noise in the channel (so that all errors in the codeword result from the deliberate actions of Alice), and the case where the channel is noisy and not controlled by Alice and Bob.

  14. Quantum steganography with noisy quantum channels

    SciTech Connect

    Shaw, Bilal A.; Brun, Todd A.

    2011-02-15

    Steganography is the technique of hiding secret information by embedding it in a seemingly ''innocent'' message. We present protocols for hiding quantum information by disguising it as noise in a codeword of a quantum error-correcting code. The sender (Alice) swaps quantum information into the codeword and applies a random choice of unitary operation, drawing on a secret random key she shares with the receiver (Bob). Using the key, Bob can retrieve the information, but an eavesdropper (Eve) with the power to monitor the channel, but without the secret key, cannot distinguish the message from channel noise. We consider two types of protocols: one in which the hidden quantum information is stored locally in the codeword, and another in which it is embedded in the space of error syndromes. We analyze how difficult it is for Eve to detect the presence of secret messages, and estimate rates of steganographic communication and secret key consumption for specific protocols and examples of error channels. We consider both the case where there is no actual noise in the channel (so that all errors in the codeword result from the deliberate actions of Alice), and the case where the channel is noisy and not controlled by Alice and Bob.

  15. Chaos in quantum channels

    NASA Astrophysics Data System (ADS)

    Hosur, Pavan; Qi, Xiao-Liang; Roberts, Daniel A.; Yoshida, Beni

    2016-02-01

    We study chaos and scrambling in unitary channels by considering their entanglement properties as states. Using out-of-time-order correlation functions to diagnose chaos, we characterize the ability of a channel to process quantum information. We show that the generic decay of such correlators implies that any input subsystem must have near vanishing mutual information with almost all partitions of the output. Additionally, we propose the negativity of the tripartite information of the channel as a general diagnostic of scrambling. This measures the delocalization of information and is closely related to the decay of out-of-time-order correlators. We back up our results with numerics in two non-integrable models and analytic results in a perfect tensor network model of chaotic time evolution. These results show that the butterfly effect in quantum systems implies the information-theoretic definition of scrambling.

  16. Chaos in quantum channels

    DOE PAGES

    Hosur, Pavan; Qi, Xiao-Liang; Roberts, Daniel A.; Yoshida, Beni

    2016-02-01

    For this research, we study chaos and scrambling in unitary channels by considering their entanglement properties as states. Using out-of-time-order correlation functions to diagnose chaos, we characterize the ability of a channel to process quantum information. We show that the generic decay of such correlators implies that any input subsystem must have near vanishing mutual information with almost all partitions of the output. Additionally, we propose the negativity of the tripartite information of the channel as a general diagnostic of scrambling. This measures the delocalization of information and is closely related to the decay of out-of-time-order correlators. We back upmore » our results with numerics in two non-integrable models and analytic results in a perfect tensor network model of chaotic time evolution. In conclusion, these results show that the butterfly effect in quantum systems implies the information-theoretic definition of scrambling.« less

  17. Channel plate for DNA sequencing

    DOEpatents

    Douthart, R.J.; Crowell, S.L.

    1998-01-13

    This invention is a channel plate that facilitates data compaction in DNA sequencing. The channel plate has a length, a width and a thickness, and further has a plurality of channels that are parallel. Each channel has a depth partially through the thickness of the channel plate. Additionally an interface edge permits electrical communication across an interface through a buffer to a deposition membrane surface. 15 figs.

  18. Channel plate for DNA sequencing

    DOEpatents

    Douthart, Richard J.; Crowell, Shannon L.

    1998-01-01

    This invention is a channel plate that facilitates data compaction in DNA sequencing. The channel plate has a length, a width and a thickness, and further has a plurality of channels that are parallel. Each channel has a depth partially through the thickness of the channel plate. Additionally an interface edge permits electrical communication across an interface through a buffer to a deposition membrane surface.

  19. Bargaining and the MISO Interference Channel

    NASA Astrophysics Data System (ADS)

    Nokleby, Matthew; Swindlehurst, A. Lee

    2009-12-01

    We examine the MISO interference channel under cooperative bargaining theory. Bargaining approaches such as the Nash and Kalai-Smorodinsky solutions have previously been used in wireless networks to strike a balance between max-sum efficiency and max-min equity in users' rates. However, cooperative bargaining for the MISO interference channel has only been studied extensively for the two-user case. We present an algorithm that finds the optimal Kalai-Smorodinsky beamformers for an arbitrary number of users. We also consider joint scheduling and beamformer selection, using gradient ascent to find a stationary point of the Kalai-Smorodinsky objective function. When interference is strong, the flexibility allowed by scheduling compensates for the performance loss due to local optimization. Finally, we explore the benefits of power control, showing that power control provides nontrivial throughput gains when the number of transmitter/receiver pairs is greater than the number of transmit antennas.

  20. Limits to Tidal Power

    NASA Astrophysics Data System (ADS)

    Garrett, C.

    2008-12-01

    Ocean tides have been proposed as a source of renewable energy, though the maximum available power may be shown to be only a fraction of the present dissipation rate of 3.5 TW, which is small compared with global insolation (nearly 105 TW), wind dissipation (103 TW), and even human power usage of 15 TW. Nonetheless, tidal power could be a useful contributor in some locations. Traditional use of tidal power, involving the trapping of water behind a barrage at high tide, can produce an average power proportional to the area of the headpond and the square of the tidal range; the power density is approximately 6 W per square meter for a tidal range of 10 m. Capital costs and fears of environmental damage have put barrage schemes in disfavor, with interest turning to the exploitation of strong tidal currents, using turbines in a manner similar to wind turbines. There is a limit to the available power, however, as adding turbines reduces the flow, ultimately reducing the power. For sinusoidal forcing of flow in a channel connecting two large open basins, the maximum available power may be shown to be given approximately by 0.2ρ g a Q_max, where ρ is the water density, g gravity, a the amplitude of the tidal sea level difference along the channel, and Q_max is the maximum volume flux in the natural state. The same formula applies if the channel is the entrance to a semi-enclosed basin, with a now the amplitude of the external tide. A flow reduction of approximately 40% is typically associated with the maximum power extraction. The power would be reduced if only smaller environmental changes are acceptable, and reduced further by drag on supporting structures, dissipation in turbine wakes, and internal inefficiencies. It can be suggested that the best use of strong, cold, tidal currents is to provide cooling water for nuclear reactors.

  1. Informational power of quantum measurements

    SciTech Connect

    Dall'Arno, Michele; D'Ariano, Giacomo Mauro; Sacchi, Massimiliano F.

    2011-06-15

    We introduce the informational power of a quantum measurement as the maximum amount of classical information that the measurement can extract from any ensemble of quantum states. We prove the additivity by showing that the informational power corresponds to the classical capacity of a quantum-classical channel. We restate the problem of evaluating the informational power as the maximization of the accessible information of a suitable ensemble. We provide a numerical algorithm to find an optimal ensemble and quantify the informational power.

  2. MOS-transistor power switches

    NASA Astrophysics Data System (ADS)

    Konev, Iu. I.; Mashukov, E. V.

    The output characteristics of vertical-channel MOS power transistors are analyzed. It is shown that it is possible to remove the basic energy and weight-volume constraints associated with the nonlinearity of the characeristics of devices with carrier injection (i.e., diodes, transistors, and thyristors). This makes it possible to increase the specific power of all types of power switches. The discussion covers switches for ac and dc power circuits, low-voltage rectifiers, and switches with pulse width modulation.

  3. Sodium channels and pain.

    PubMed

    Habib, Abdella M; Wood, John N; Cox, James J

    2015-01-01

    Human and mouse genetic studies have led to significant advances in our understanding of the role of voltage-gated sodium channels in pain pathways. In this chapter, we focus on Nav1.7, Nav1.8, Nav1.9 and Nav1.3 and describe the insights gained from the detailed analyses of global and conditional transgenic Nav knockout mice in terms of pain behaviour. The spectrum of human disorders caused by mutations in these channels is also outlined, concluding with a summary of recent progress in the development of selective Nav1.7 inhibitors for the treatment of pain. PMID:25846613

  4. Zeolites: Exploring Molecular Channels

    SciTech Connect

    Arslan, Ilke; Derewinski, Mirek

    2015-05-22

    Synthetic zeolites contain microscopic channels, sort of like a sponge. They have many uses, such as helping laundry detergent lather, absorbing liquid in kitty litter, and as catalysts to produce fuel. Of the hundreds of types of zeolites, only about 15 are used for catalysis. PNNL catalysis scientists Ilke Arslan and Mirek Derewinksi are studying these zeolites to understand what make them special. By exploring the mystery of these microscopic channels, their fundamental findings will help design better catalysts for applications such as biofuel production.

  5. Multi-channel nonlinearity compensation of PDM-QPSK signals in dispersion-managed transmission using dispersion-folded digital backward propagation.

    PubMed

    Xia, Cen; Liu, Xiang; Chandrasekhar, S; Fontaine, N K; Zhu, Likai; Li, G

    2014-03-10

    We demonstrate nonlinearity compensation of 37.5-GHz-spaced 128-Gb/s PDM-QPSK signals using dispersion-folded digital-backward-propagation and a spectrally-sliced receiver that simultaneously receives three WDM signals, showing mitigation of intra-channel and inter-channel nonlinear effects in a 2560-km dispersion-managed TWRS-fiber link. Intra-channel and adjacent inter-channel nonlinear compensation gains when WDM channels are fully populated in the C-band are estimated based on the GN-model. PMID:24663923

  6. Multi-channel nonlinearity compensation of PDM-QPSK signals in dispersion-managed transmission using dispersion-folded digital backward propagation.

    PubMed

    Xia, Cen; Liu, Xiang; Chandrasekhar, S; Fontaine, N K; Zhu, Likai; Li, G

    2014-03-10

    We demonstrate nonlinearity compensation of 37.5-GHz-spaced 128-Gb/s PDM-QPSK signals using dispersion-folded digital-backward-propagation and a spectrally-sliced receiver that simultaneously receives three WDM signals, showing mitigation of intra-channel and inter-channel nonlinear effects in a 2560-km dispersion-managed TWRS-fiber link. Intra-channel and adjacent inter-channel nonlinear compensation gains when WDM channels are fully populated in the C-band are estimated based on the GN-model.

  7. Narrowband land mobile satellite channel modeling

    NASA Technical Reports Server (NTRS)

    Kanatas, A. G.; Kanderakis, E. C.; Constantinou, P.

    1995-01-01

    The subject of this paper is the development of a generalized analog model for the narrowband Land Mobile Satellite Channel (LMSC). It is based on the model proposed by Lutz, the 3-dimensional scattering model of Aulin and the multipath interference simulation method proposed by Jakes. Statistical tests of the simulated data show excellent agreement with the expected distributions whereas the power spectrum predicted by Aulin is duplicated in a discrete manner.

  8. Radiologic Changes of Operated and Adjacent Segments after Anterior Cervical Microforaminotomy

    PubMed Central

    Ahn, Jang Ho; Park, Moon Sun; Kim, Seong Min; Chung, Seung Young; Lee, Do Sung

    2016-01-01

    Objective Anterior cervical microforaminotomy (ACMF) is a motion-preserving surgical procedure. The purpose of this study is to assess radiologic changes of operated and adjacent segments after ACMF. Methods We retrospectively reviewed 52 patients who underwent ACMF between 1998 and 2008. From X-ray film-based changes, disc height and sagittal range of motion (ROM) of operated and adjacent segments were compared at preoperative and last follow-up periods. Radiological degeneration of both segments was analyzed as well. Results The mean follow-up period was 48.2 months. There were 78 operated, 52 upper adjacent, and 38 lower adjacent segments. There were statistically significant differences in the ROM and disc height of operated segment between preoperative and last follow-up periods. However, there were no statistically significant differences in the ROM and disc height of adjacent segment between both periods. Radiological degenerative changes of operated segments were observed in 30%. That of adjacent segments was observed in 11 and 11% at upper and lower segments, respectively. Conclusion After mean 4-year follow-up periods, there were degenerative changes of operated segments. However, ACMF preserved motion and prevented degenerative changes of adjacent segments. PMID:27799993

  9. A modern analog for carbonate source-to-sink sedimentary systems: the Glorieuses archipelago and adjacent basin (SW Indian Ocean)

    NASA Astrophysics Data System (ADS)

    Jorry, S.; Jouet, G.; Prat, S.; Courgeon, S.; Le Roy, P.; Camoin, G.; Caline, B.

    2014-12-01

    This study presents the geomorphological and sedimentological analysis of a modern carbonate source-to-sink system located north of Madagascar (SW Indian Ocean). The sedimentary system is composed of an isolated carbonate platform sited on top of a seamount rising steeply from the seabed located at 3000 m water depth. The slope of the seamount is incised by canyons, and meandering channels occur above lobbed sedimentary bodies at the foot of the slope. The dataset consists of dredges, sediment piston cores, swath bathymetry and seismic (sparker and 2D high-resolution) lines collected from inner platform (less than 5 m deep) to the adjacent deep sedimentary basin. Particle size analysis and composition of carbonate grains are used to characterize the distribution and heterogeneity of sands accumulated on the archipelago. Main results show that composition of carbonate sediments is dominated by segments of Halimeda, large benthic foraminifera, coral debris, molluscs, echinoderms, bryozoans and sponges. According to the shape and the position of sandwaves and intertidal sandbars developed in the back-barrier reef, the present organization of these well-sorted fine-sand accumulations appears to be strongly influenced by flood tidal currents. Seismic lines acquired from semi-enclosed to open lagoon demonstrate that most of the sediment is exported and accumulated along the leeward margin of the platform, which is connected to a canyon network incising the outer slope. Following the concept of highstand shedding of carbonate platforms (Schlager et al., 1994), excess sediment is exported by plumes and gravity flows to the adjacent deep sea where it feeds a carbonate deep-sea fan. Combined observations from platform to basin allow to explain how the Glorieuses carbonate source to sink system has evolved under the influence of climate and of relative sea-level changes since the last interglacial.

  10. Channels of Propaganda.

    ERIC Educational Resources Information Center

    Sproule, J. Michael

    Defining propaganda as "efforts by special interests to win over the public covertly by infiltrating messages into various channels of public expression ordinarily viewed as politically neutral," this book argues that propaganda has become pervasive in American life. Pointing out that the 1990s society is inundated with propaganda from numerous…

  11. Learning in Tactile Channels

    ERIC Educational Resources Information Center

    Gescheider, George A.; Wright, John H.

    2012-01-01

    Vibrotactile intensity-discrimination thresholds for sinusoidal stimuli applied to the thenar eminence of the hand declined as a function of practice. However, improvement was confined to the tactile information-processing channel in which learning had occurred. Specifically, improvements in performance with training within the Pacinian-corpuscle…

  12. SK channels and calmodulin.

    PubMed

    Adelman, John P

    2016-01-01

    Calcium ions are Nature's most widely used signaling mechanism, mediating communication between pathways at virtually every physiological level. Ion channels are no exception, as the activities of a wide range of ion channels are intricately shaped by fluctuations in intracellular Ca(2+) levels. Mirroring the importance and the breadth of Ca(2+) signaling, free Ca(2+) levels are tightly controlled, and a myriad of Ca(2+) binding proteins transduce Ca(2+) signals, each with its own nuance, comprising a constantly changing symphony of metabolic activity. The founding member of Ca(2+) binding proteins is calmodulin (CaM), a small, acidic, modular protein endowed with gymnastic-like flexibility and E-F hand motifs that chelate Ca(2+) ions. In this review, I will trace the history that led to the realization that CaM serves as the Ca(2+)-gating cue for SK channels, the experiments that revealed that CaM is an intrinsic subunit of SK channels, and itself a target of regulation. PMID:25942650

  13. Chemistry in Microfluidic Channels

    ERIC Educational Resources Information Center

    Chia, Matthew C.; Sweeney, Christina M.; Odom, Teri W.

    2011-01-01

    General chemistry introduces principles such as acid-base chemistry, mixing, and precipitation that are usually demonstrated in bulk solutions. In this laboratory experiment, we describe how chemical reactions can be performed in a microfluidic channel to show advanced concepts such as laminar fluid flow and controlled precipitation. Three sets of…

  14. Developments in relativistic channeling

    SciTech Connect

    Carrigan, R.A. Jr.

    1996-10-01

    The possibility of using channeling as a tool for high energy accelerator applications and particle physics has now been extensively investigated. Bent crystals have been used for accelerator extraction and for particle deflection. Applications as accelerating devices have been discussed but have not yet been tried. 61 refs., 1 fig.

  15. Single- and multi-channel underwater acoustic communication channel capacity: a computational study.

    PubMed

    Hayward, Thomas J; Yang, T C

    2007-09-01

    Acoustic communication channel capacity determines the maximum data rate that can be supported by an acoustic channel for a given source power and source/receiver configuration. In this paper, broadband acoustic propagation modeling is applied to estimate the channel capacity for a time-invariant shallow-water waveguide for a single source-receiver pair and for vertical source and receiver arrays. Without bandwidth constraints, estimated single-input, single-output (SISO) capacities approach 10 megabitss at 1 km range, but beyond 2 km range they decay at a rate consistent with previous estimates by Peloquin and Leinhos (unpublished, 1997), which were based on a sonar equation calculation. Channel capacities subject to source bandwidth constraints are approximately 30-90% lower than for the unconstrained case, and exhibit a significant wind speed dependence. Channel capacity is investigated for single-input, multi-output (SIMO) and multi-input, multi-output (MIMO) systems, both for finite arrays and in the limit of a dense array spanning the entire water column. The limiting values of the SIMO and MIMO channel capacities for the modeled environment are found to be about four times higher and up to 200-400 times higher, respectively, than for the SISO case. Implications for underwater acoustic communication systems are discussed.

  16. The land mobile satellite communication channel - Recording, statistics, and channel model

    NASA Astrophysics Data System (ADS)

    Lutz, Erich; Cygan, Daniel; Dippold, Michael; Dolainsky, Frank; Papke, Wolfgang

    1991-05-01

    The communication channel between the MARECS satellite at 26 deg W and a cruising van was measured and recorded in European areas exhibiting satellite elevations from 13 to 43 deg. Different environments and mobile antennas were tested. Results of an extensive statistical evaluation include spectra of the fading amplitude, probability density, and distribution of the received signal power as well as the percentage of time for fade and nonfade periods. Based on the physical phenomena of multipath fading and signal shadowing, an analog model of the land mobile satellite channel which can readily be used for software and hardware fading simulation is developed. The most important parameter of this model is the time-share of shadowing, A, ranging from less than 1 percent on southern highways to 89 percent in the city of Stockholm. The Rice factor, c, which characterizes the channel during unshadowed periods, can vary from 3.9 to 18.1 dB. For analytical purposes, the land mobile satellite channel can be represented by a digital two-state Gilbert-Elliott model. For DPSK (differential phase-shift keying) modulation with a 10-dB signal-to-noise ratio in the satellite link, the mean bit error probability in the unshadowed channel state is typically in the range of 0.0001-0.01, while it is around 0.3 in the shadowed channel state. With regard to data transmission, block error probability density, error gap distribution, and block error probability are discussed.

  17. Conversion of borehole Stoneley waves to channel waves in coal

    SciTech Connect

    Johnson, P.A.; Albright, J.N.

    1987-01-01

    Evidence for the mode conversion of borehole Stoneley waves to stratigraphically guided channel waves was discovered in data from a crosswell acoustic experiment conducted between wells penetrating thin coal strata located near Rifle, Colorado. Traveltime moveout observations show that borehole Stoneley waves, excited by a transmitter positioned at substantial distances in one well above and below a coal stratum at 2025 m depth, underwent partial conversion to a channel wave propagating away from the well through the coal. In an adjacent well the channel wave was detected at receiver locations within the coal, and borehole Stoneley waves, arising from a second partial conversion of channel waves, were detected at locations above and below the coal. The observed channel wave is inferred to be the third-higher Rayleigh mode based on comparison of the measured group velocity with theoretically derived dispersion curves. The identification of the mode conversion between borehole and stratigraphically guided waves is significant because coal penetrated by multiple wells may be detected without placing an acoustic transmitter or receiver within the waveguide. 13 refs., 6 figs., 1 tab.

  18. Surface-directed boundary flow in microfluidic channels.

    PubMed

    Huang, Tom T; Taylor, David G; Lim, Kwan Seop; Sedlak, Miroslav; Bashir, Rashid; Mosier, Nathan S; Ladisch, Michael R

    2006-07-01

    Channel geometry combined with surface chemistry enables a stable liquid boundary flow to be attained along the surfaces of a 12 microm diameter hydrophilic glass fiber in a closed semi-elliptical channel. Surface free energies and triangular corners formed by PDMS/glass fiber or OTS/glass fiber surfaces are shown to be responsible for the experimentally observed wetting phenomena and formation of liquid boundary layers that are 20-50 microm wide and 12 microm high. Viewing this stream through a 20 microm slit results in a virtual optical window with a 5 pL liquid volume suitable for cell counting and pathogen detection. The geometry that leads to the boundary layer is a closed channel that forms triangular corners where glass fiber and the OTS coated glass slide or PDMS touch. The contact angles and surfaces direct positioning of the fluid next to the fiber. Preferential wetting of corner regions initiates the boundary flow, while the elliptical cross-section of the channel stabilizes the microfluidic flow. The Young-Laplace equation, solved using fluid dynamic simulation software, shows contact angles that exceed 105 degrees will direct the aqueous fluid to a boundary layer next to a hydrophilic fiber with a contact angle of 5 degrees. We believe this is the first time that an explanation has been offered for the case of a boundary layer formation in a closed channel directed by a triangular geometry with two hydrophobic wetting edges adjacent to a hydrophilic surface. PMID:16800710

  19. Channeling through Bent Crystals

    SciTech Connect

    Mack, Stephanie; /Ottawa U. /SLAC

    2012-09-07

    Bent crystals have demonstrated potential for use in beam collimation. A process called channeling is when accelerated particle beams are trapped by the nuclear potentials in the atomic planes within a crystal lattice. If the crystal is bent then the particles can follow the bending angle of the crystal. There are several different effects that are observed when particles travel through a bent crystal including dechanneling, volume capture, volume reflection and channeling. With a crystal placed at the edge of a particle beam, part of the fringe of the beam can be deflected away towards a detector or beam dump, thus helping collimate the beam. There is currently FORTRAN code by Igor Yazynin that has been used to model the passage of particles through a bent crystal. Using this code, the effects mentioned were explored for beam energy that would be seen at the Facility for Advanced Accelerator Experimental Tests (FACET) at a range of crystal orientations with respect to the incoming beam. After propagating 5 meters in vacuum space past the crystal the channeled particles were observed to separate from most of the beam with some noise due to dechanneled particles. Progressively smaller bending radii, with corresponding shorter crystal lengths, were compared and it was seen that multiple scattering decreases with the length of the crystal therefore allowing for cleaner detection of the channeled particles. The input beam was then modified and only a portion of the beam sent through the crystal. With the majority of the beam not affected by the crystal, most particles were not deflected and after propagation the channeled particles were seen to be deflected approximately 5mm. After a portion of the beam travels through the crystal, the entire beam was then sent through a quadrupole magnet, which increased the separation of the channeled particles from the remainder of the beam to a distance of around 20mm. A different code, which was developed at SLAC, was used to

  20. Channel pattern and river-floodplain dynamics in forested mountain river systems

    NASA Astrophysics Data System (ADS)

    Beechie, Timothy J.; Liermann, Martin; Pollock, Michael M.; Baker, Sarah; Davies, Jeremy

    2006-08-01

    Channel pattern effectively stratifies the dynamics of rivers and floodplains in forested mountain river systems of the Pacific Northwest, USA. Straight channels are least dynamic, with relatively slow floodplain turnover and floodplains dominated by old surfaces. Braided channels are most dynamic, with floodplain turnover as low as 25 years and predominantly young floodplain surfaces. Island-braided and meandering channels have intermediate dynamics, with moderately frequent disturbances (erosion of floodplain patches) maintaining a mix of old and young surfaces. Return intervals for the erosion of floodplains increase in the order of braided, island-braided, meandering, and straight (8, 33, 60, and 89 years, respectively). A threshold for the lateral migration of a channel occurs at a bankfull width of 15-20 m. The most likely mechanism underlying this threshold is that larger channels are deep enough to erode below the rooting zone of bank vegetation. Above this threshold, channels not confined between valley walls exhibit channel patterns distinguishable by slope and discharge, and slope-discharge domains can be used to predict channel patterns. Meandering and braided patterns are most consistently identified by the model, and prediction errors are largely associated with indistinct transitions among channel patterns that are adjacent in plots of slope against discharge. Locations of straight channels are difficult to identify accurately with the current model. The predicted spatial distribution of channel patterns reflects a downstream decline in channel slope, which is likely correlated with a declining ratio of bed load to suspended load. Ecological theory suggests that biological diversity should be highest where the intermediate disturbance regime of island-braided channels sustains high diversity of habitat and successional states through time.