Sample records for rectangular navigation channel

  1. Bend losses in rectangular culverts.

    DOT National Transportation Integrated Search

    2008-09-01

    This study investigated bend losses for open channel flow in rectangular channels or culverts. Laboratory experiments were performed for sub-critical flow in rectangular channels with abrupt bends. Bend angles of approximately 30, 45, 60, 75 and 90 d...

  2. Insights from depth-averaged numerical simulation of flow at bridge abutments in compound channels.

    DOT National Transportation Integrated Search

    2011-07-01

    Two-dimensional, depth-averaged flow models are used to study the distribution of flow around spill-through abutments situated on floodplains in compound channels and rectangular channels (flow on very wide floodplains may be treated as rectangular c...

  3. The study and development of the empirical correlations equation of natural convection heat transfer on vertical rectangular sub-channels

    NASA Astrophysics Data System (ADS)

    Kamajaya, Ketut; Umar, Efrizon; Sudjatmi, K. S.

    2012-06-01

    This study focused on natural convection heat transfer using a vertical rectangular sub-channel and water as the coolant fluid. To conduct this study has been made pipe heaters are equipped with thermocouples. Each heater is equipped with five thermocouples along the heating pipes. The diameter of each heater is 2.54 cm and 45 cm in length. The distance between the central heating and the pitch is 29.5 cm. Test equipment is equipped with a primary cooling system, a secondary cooling system and a heat exchanger. The purpose of this study is to obtain new empirical correlations equations of the vertical rectangular sub-channel, especially for the natural convection heat transfer within a bundle of vertical cylinders rectangular arrangement sub-channels. The empirical correlation equation can support the thermo-hydraulic analysis of research nuclear reactors that utilize cylindrical fuel rods, and also can be used in designing of baffle-free vertical shell and tube heat exchangers. The results of this study that the empirical correlation equations of natural convection heat transfer coefficients with rectangular arrangement is Nu = 6.3357 (Ra.Dh/x)0.0740.

  4. Computational Investigations in Rectangular Convergent and Divergent Ribbed Channels

    NASA Astrophysics Data System (ADS)

    Sivakumar, Karthikeyan; Kulasekharan, N.; Natarajan, E.

    2018-05-01

    Computational investigations on the rib turbulated flow inside a convergent and divergent rectangular channel with square ribs of different rib heights and different Reynolds numbers (Re=20,000, 40,000 and 60,000). The ribs were arranged in a staggered fashion between the upper and lower surfaces of the test section. Computational investigations are carried out using computational fluid dynamic software ANSYS Fluent 14.0. Suitable solver settings like turbulence models were identified from the literature and the boundary conditions for the simulations on a solution of independent grid. Computations were carried out for both convergent and divergent channels with 0 (smooth duct), 1.5, 3, 6, 9 and 12 mm rib heights, to identify the ribbed channel with optimal performance, assessed using a thermo hydraulic performance parameter. The convergent and divergent rectangular channels show higher Nu values than the standard correlation values.

  5. Study of gas-water flow in horizontal rectangular channels

    NASA Astrophysics Data System (ADS)

    Chinnov, E. A.; Ron'shin, F. V.; Kabov, O. A.

    2015-09-01

    The two-phase flow in the narrow short horizontal rectangular channels 1 millimeter in height was studied experimentally. The features of formation of the two-phase flow were studied in detail. It is shown that with an increase in the channel width, the region of the churn and bubble regimes increases, compressing the area of the jet flow. The areas of the annular and stratified flow patterns vary insignificantly.

  6. Use of navigation channels by Lake Sturgeon: Does channelization increase vulnerability of fish to ship strikes?

    PubMed

    Hondorp, Darryl W; Bennion, David H; Roseman, Edward F; Holbrook, Christopher M; Boase, James C; Chiotti, Justin A; Thomas, Michael V; Wills, Todd C; Drouin, Richard G; Kessel, Steven T; Krueger, Charles C

    2017-01-01

    Channelization for navigation and flood control has altered the hydrology and bathymetry of many large rivers with unknown consequences for fish species that undergo riverine migrations. In this study, we investigated whether altered flow distributions and bathymetry associated with channelization attracted migrating Lake Sturgeon (Acipenser fulvescens) into commercial navigation channels, potentially increasing their exposure to ship strikes. To address this question, we quantified and compared Lake Sturgeon selection for navigation channels vs. alternative pathways in two multi-channel rivers differentially affected by channelization, but free of barriers to sturgeon movement. Acoustic telemetry was used to quantify Lake Sturgeon movements. Under the assumption that Lake Sturgeon navigate by following primary flow paths, acoustic-tagged Lake Sturgeon in the more-channelized lower Detroit River were expected to choose navigation channels over alternative pathways and to exhibit greater selection for navigation channels than conspecifics in the less-channelized lower St. Clair River. Consistent with these predictions, acoustic-tagged Lake Sturgeon in the more-channelized lower Detroit River selected the higher-flow and deeper navigation channels over alternative migration pathways, whereas in the less-channelized lower St. Clair River, individuals primarily used pathways alternative to navigation channels. Lake Sturgeon selection for navigation channels as migratory pathways also was significantly higher in the more-channelized lower Detroit River than in the less-channelized lower St. Clair River. We speculated that use of navigation channels over alternative pathways would increase the spatial overlap of commercial vessels and migrating Lake Sturgeon, potentially enhancing their vulnerability to ship strikes. Results of our study thus demonstrated an association between channelization and the path use of migrating Lake Sturgeon that could prove important for predicting sturgeon-vessel interactions in navigable rivers as well as for understanding how fish interact with their habitat in landscapes altered by human activity.

  7. Use of navigation channels by Lake Sturgeon: Does channelization increase vulnerability of fish to ship strikes?

    PubMed Central

    Bennion, David H.; Roseman, Edward F.; Holbrook, Christopher M.; Boase, James C.; Chiotti, Justin A.; Thomas, Michael V.; Wills, Todd C.; Drouin, Richard G.; Kessel, Steven T.; Krueger, Charles C.

    2017-01-01

    Channelization for navigation and flood control has altered the hydrology and bathymetry of many large rivers with unknown consequences for fish species that undergo riverine migrations. In this study, we investigated whether altered flow distributions and bathymetry associated with channelization attracted migrating Lake Sturgeon (Acipenser fulvescens) into commercial navigation channels, potentially increasing their exposure to ship strikes. To address this question, we quantified and compared Lake Sturgeon selection for navigation channels vs. alternative pathways in two multi-channel rivers differentially affected by channelization, but free of barriers to sturgeon movement. Acoustic telemetry was used to quantify Lake Sturgeon movements. Under the assumption that Lake Sturgeon navigate by following primary flow paths, acoustic-tagged Lake Sturgeon in the more-channelized lower Detroit River were expected to choose navigation channels over alternative pathways and to exhibit greater selection for navigation channels than conspecifics in the less-channelized lower St. Clair River. Consistent with these predictions, acoustic-tagged Lake Sturgeon in the more-channelized lower Detroit River selected the higher-flow and deeper navigation channels over alternative migration pathways, whereas in the less-channelized lower St. Clair River, individuals primarily used pathways alternative to navigation channels. Lake Sturgeon selection for navigation channels as migratory pathways also was significantly higher in the more-channelized lower Detroit River than in the less-channelized lower St. Clair River. We speculated that use of navigation channels over alternative pathways would increase the spatial overlap of commercial vessels and migrating Lake Sturgeon, potentially enhancing their vulnerability to ship strikes. Results of our study thus demonstrated an association between channelization and the path use of migrating Lake Sturgeon that could prove important for predicting sturgeon-vessel interactions in navigable rivers as well as for understanding how fish interact with their habitat in landscapes altered by human activity. PMID:28678798

  8. Regimes of Two-Phase Flow in Short Rectangular Channel

    NASA Astrophysics Data System (ADS)

    Chinnov, Evgeny A.; Guzanov, Vladimir V.; Cheverda, Vyacheslav; Markovich, Dmitry M.; Kabov, Oleg A.

    2009-08-01

    Experimental study of two-phase flow in the short rectangular horizontal channel with height 440 μm has been performed. Characteristics of liquid motion inside the channel have been registered and measured by the Laser Induced Fluorescence technique. New information has allowed determining more precisely the characteristics of churn regime and boundaries between different regimes of two-phase flow. It was shown that formation of some two-phase flow regimes and transitions between them are determined by instability of the flow in the lateral parts of the channel.

  9. 33 CFR 162.260 - Channel leading to San Juan Harbor, P.R.; use, administration, and navigation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Channel leading to San Juan Harbor, P.R.; use, administration, and navigation. 162.260 Section 162.260 Navigation and Navigable... WATERWAYS NAVIGATION REGULATIONS § 162.260 Channel leading to San Juan Harbor, P.R.; use, administration...

  10. 33 CFR 162.260 - Channel leading to San Juan Harbor, P.R.; use, administration, and navigation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Channel leading to San Juan Harbor, P.R.; use, administration, and navigation. 162.260 Section 162.260 Navigation and Navigable... WATERWAYS NAVIGATION REGULATIONS § 162.260 Channel leading to San Juan Harbor, P.R.; use, administration...

  11. Computational analysis of electrokinetically driven flow mixing in microchannels with patterned blocks

    NASA Astrophysics Data System (ADS)

    Chang, C.-C.; Yang, R.-J.

    2004-04-01

    Electroosmotic flow in microchannels is restricted to low Reynolds number regimes characterized by extremely weak inertia forces and laminar flow. Consequently, the mixing of different species occurs primarily through diffusion, and hence cannot readily be achieved within a short mixing channel. The current study presents a numerical investigation of electrokinetically driven flow mixing in microchannels with various numbers of incorporated patterned rectangular blocks. Furthermore, a novel approach is introduced which patterns heterogeneous surfaces on the upper faces of these rectangular blocks in order to enhance species mixing. The simulation results confirm that the introduction of rectangular blocks within the mixing channel slightly enhances species mixing by constricting the bulk flow, hence creating a stronger diffusion effect. However, it is noted that a large number of blocks and hence a long mixing channel are required if a complete mixing of the species is to be obtained. The results also indicate that patterning heterogeneous upper surfaces on the rectangular blocks is an effective means of enhancing the species mixing. It is shown that increasing the magnitude of the heterogeneous surface zeta potential enables a reduction in the mixing channel length and an improved degree of mixing efficiency.

  12. Rapid and efficient mixing in a slip-driven three-dimensional flow in a rectangular channel

    NASA Astrophysics Data System (ADS)

    Pacheco, J. Rafael; Ping Chen, Kang; Hayes, Mark A.

    2006-08-01

    A method for generating mixing in an electroosmotic flow of an electrolytic solution in a three-dimensional channel is proposed. When the width-to-height aspect ratio of the channel cross-section is large, mixing of a blob of a solute in a slip-driven three-dimensional flow in a rectangular channel can be used to model and assess the effectiveness of this method. It is demonstrated through numerical simulations that under certain operating conditions, rapid and efficient mixing can be achieved. Future investigation will include the solution of the exact equations and experimentation.

  13. Somersault of Paramecium in extremely confined environments.

    PubMed

    Jana, Saikat; Eddins, Aja; Spoon, Corrie; Jung, Sunghwan

    2015-08-19

    We investigate various swimming modes of Paramecium in geometric confinements and a non-swimming self-bending behavior like a somersault, which is quite different from the previously reported behaviors. We observe that Paramecia execute directional sinusoidal trajectories in thick fluid films, whereas Paramecia meander around a localized region and execute frequent turns due to collisions with adjacent walls in thin fluid films. When Paramecia are further constrained in rectangular channels narrower than the length of the cell body, a fraction of meandering Paramecia buckle their body by pushing on the channel walls. The bucking (self-bending) of the cell body allows the Paramecium to reorient its anterior end and explore a completely new direction in extremely confined spaces. Using force deflection method, we quantify the Young's modulus of the cell and estimate the swimming and bending powers exerted by Paramecium. The analysis shows that Paramecia can utilize a fraction of its swimming power to execute the self-bending maneuver within the confined channel and no extra power may be required for this new kind of self-bending behavior. This investigation sheds light on how micro-organisms can use the flexibility of the body to actively navigate within confined spaces.

  14. Somersault of Paramecium in extremely confined environments

    PubMed Central

    Jana, Saikat; Eddins, Aja; Spoon, Corrie; Jung, Sunghwan

    2015-01-01

    We investigate various swimming modes of Paramecium in geometric confinements and a non-swimming self-bending behavior like a somersault, which is quite different from the previously reported behaviors. We observe that Paramecia execute directional sinusoidal trajectories in thick fluid films, whereas Paramecia meander around a localized region and execute frequent turns due to collisions with adjacent walls in thin fluid films. When Paramecia are further constrained in rectangular channels narrower than the length of the cell body, a fraction of meandering Paramecia buckle their body by pushing on the channel walls. The bucking (self-bending) of the cell body allows the Paramecium to reorient its anterior end and explore a completely new direction in extremely confined spaces. Using force deflection method, we quantify the Young’s modulus of the cell and estimate the swimming and bending powers exerted by Paramecium. The analysis shows that Paramecia can utilize a fraction of its swimming power to execute the self-bending maneuver within the confined channel and no extra power may be required for this new kind of self-bending behavior. This investigation sheds light on how micro-organisms can use the flexibility of the body to actively navigate within confined spaces. PMID:26286234

  15. Somersault of Paramecium in extremely confined environments

    NASA Astrophysics Data System (ADS)

    Jana, Saikat; Eddins, Aja; Spoon, Corrie; Jung, Sunghwan

    2015-08-01

    We investigate various swimming modes of Paramecium in geometric confinements and a non-swimming self-bending behavior like a somersault, which is quite different from the previously reported behaviors. We observe that Paramecia execute directional sinusoidal trajectories in thick fluid films, whereas Paramecia meander around a localized region and execute frequent turns due to collisions with adjacent walls in thin fluid films. When Paramecia are further constrained in rectangular channels narrower than the length of the cell body, a fraction of meandering Paramecia buckle their body by pushing on the channel walls. The bucking (self-bending) of the cell body allows the Paramecium to reorient its anterior end and explore a completely new direction in extremely confined spaces. Using force deflection method, we quantify the Young’s modulus of the cell and estimate the swimming and bending powers exerted by Paramecium. The analysis shows that Paramecia can utilize a fraction of its swimming power to execute the self-bending maneuver within the confined channel and no extra power may be required for this new kind of self-bending behavior. This investigation sheds light on how micro-organisms can use the flexibility of the body to actively navigate within confined spaces.

  16. One-dimensional acoustic standing waves in rectangular channels for flow cytometry.

    PubMed

    Austin Suthanthiraraj, Pearlson P; Piyasena, Menake E; Woods, Travis A; Naivar, Mark A; Lόpez, Gabriel P; Graves, Steven W

    2012-07-01

    Flow cytometry has become a powerful analytical tool for applications ranging from blood diagnostics to high throughput screening of molecular assemblies on microsphere arrays. However, instrument size, expense, throughput, and consumable use limit its use in resource poor areas of the world, as a component in environmental monitoring, and for detection of very rare cell populations. For these reasons, new technologies to improve the size and cost-to-performance ratio of flow cytometry are required. One such technology is the use of acoustic standing waves that efficiently concentrate cells and particles to the center of flow channels for analysis. The simplest form of this method uses one-dimensional acoustic standing waves to focus particles in rectangular channels. We have developed one-dimensional acoustic focusing flow channels that can be fabricated in simple capillary devices or easily microfabricated using photolithography and deep reactive ion etching. Image and video analysis demonstrates that these channels precisely focus single flowing streams of particles and cells for traditional flow cytometry analysis. Additionally, use of standing waves with increasing harmonics and in parallel microfabricated channels is shown to effectively create many parallel focused streams. Furthermore, we present the fabrication of an inexpensive optical platform for flow cytometry in rectangular channels and use of the system to provide precise analysis. The simplicity and low-cost of the acoustic focusing devices developed here promise to be effective for flow cytometers that have reduced size, cost, and consumable use. Finally, the straightforward path to parallel flow streams using one-dimensional multinode acoustic focusing, indicates that simple acoustic focusing in rectangular channels may also have a prominent role in high-throughput flow cytometry. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. Measurement of heat transfer and pressure drop in rectangular channels with turbulence promoters

    NASA Technical Reports Server (NTRS)

    Han, J. C.; Park, J. S.; Ibrahim, M. Y.

    1986-01-01

    Periodic rib turbulators were used in advanced turbine cooling designs to enhance the internal heat transfer. The objective of the present project was to investigate the combined effects of the rib angle of attack and the channel aspect ratio on the local heat transfer and pressure drop in rectangular channels with two opposite ribbed walls for Reynolds number varied from 10,000 to 60,000. The channel aspect ratio (W/H) was varied from 1 to 2 to 4. The rib angle of attack (alpha) was varied from 90 to 60 to 45 to 30 degree. The highly detailed heat transfer coefficient distribution on both the smooth side and the ribbed side walls from the channel sharp entrance to the downstream region were measured. The results showed that, in the square channel, the heat transfer for the slant ribs (alpha = 30 -45 deg) was about 30% higher that of the transverse ribs (alpha = 90 deg) for a constant pumping power. However, in the rectangular channels (W/H = 2 and 4, ribs on W side), the heat transfer at alpha = 30 -45 deg was only about 5% higher than 90 deg. The average heat transfer and friction correlations were developed to account for rib spacing, rib angle, and channel aspect ratio over the range of roughness Reynolds number.

  18. 33 CFR 334.260 - York River, Va.; naval restricted areas.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ....; naval restricted areas. (a) The areas—(1) Naval mine service-testing area (prohibited). A rectangular... 76°31′50″ W.; and thence along the shore line to the point of beginning. (2) Naval mine service... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false York River, Va.; naval restricted...

  19. 33 CFR 334.260 - York River, Va.; naval restricted areas.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ....; naval restricted areas. (a) The areas—(1) Naval mine service-testing area (prohibited). A rectangular... 76°31′50″ W.; and thence along the shore line to the point of beginning. (2) Naval mine service... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false York River, Va.; naval restricted...

  20. 33 CFR 334.260 - York River, Va.; naval restricted areas.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ....; naval restricted areas. (a) The areas—(1) Naval mine service-testing area (prohibited). A rectangular... 76°31′50″ W.; and thence along the shore line to the point of beginning. (2) Naval mine service... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false York River, Va.; naval restricted...

  1. National Dam Safety Program. Roxbury Dam (Inventory Number 788) Delaware River Basin, Delaware County, New York. Phase I Inspection Report,

    DTIC Science & Technology

    1980-05-21

    service spillway was analyzed as a sharp - crested weir with:.a discharge coefficient (c) of 3.1. The auxiliary spillway channel was analyzed as a broad ...upstream portion of this channel is a concrete structure which forms a 27.4 foot long rectangular weir . There is a 5 foot vertical drop beyond the crest ...I on 1.5 Crest Width (ft) 12 g. Service Spillway Type: Concrete channel-rectangular weir . Five foot vertical drop beyond crest . Masonry and laid up

  2. Two-phase flow in short horizontal rectangular microchannels with a height of 300 μm

    NASA Astrophysics Data System (ADS)

    Chinnov, E. A.; Ron'shin, F. V.; Kabov, O. A.

    2015-09-01

    The two-phase flow in a narrow short horizontal channel with a rectangular cross section is studied experimentally. The channel has a width of 10, 20, or 30 mm and a height of 300 μm. The specifics of formation of such two-phase flows are investigated. It is demonstrated that the regions of bubble and churn flow regimes grow and constrain the region of jet flow as the channel gets wider. The boundaries of the regions of annular and stratified flow regimes remain almost unaltered.

  3. 33 CFR 80.1122 - Channel Islands Harbor, CA.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1122 Channel Islands Harbor, CA. (a) A line drawn from Channel Islands Harbor South Jetty Light 2 to Channel Islands Harbor Breakwater... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Channel Islands Harbor, CA. 80...

  4. 33 CFR 80.1122 - Channel Islands Harbor, CA.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1122 Channel Islands Harbor, CA. (a) A line drawn from Channel Islands Harbor South Jetty Light 2 to Channel Islands Harbor Breakwater... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Channel Islands Harbor, CA. 80...

  5. 33 CFR 80.1122 - Channel Islands Harbor, CA.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1122 Channel Islands Harbor, CA. (a) A line drawn from Channel Islands Harbor South Jetty Light 2 to Channel Islands Harbor Breakwater... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Channel Islands Harbor, CA. 80...

  6. 33 CFR 80.1122 - Channel Islands Harbor, CA.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1122 Channel Islands Harbor, CA. (a) A line drawn from Channel Islands Harbor South Jetty Light 2 to Channel Islands Harbor Breakwater... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Channel Islands Harbor, CA. 80...

  7. 33 CFR 80.1122 - Channel Islands Harbor, CA.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1122 Channel Islands Harbor, CA. (a) A line drawn from Channel Islands Harbor South Jetty Light 2 to Channel Islands Harbor Breakwater... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Channel Islands Harbor, CA. 80...

  8. Polydisperse particle-driven gravity currents in non-rectangular cross section channels

    NASA Astrophysics Data System (ADS)

    Zemach, T.

    2018-01-01

    We consider a high-Reynolds-number gravity current generated by polydisperse suspension of n types of particles distributed in a fluid of density ρi. Each class of particles in suspension has a different settling velocity. The current propagates along a channel of non-rectangular cross section into an ambient fluid of constant density ρa. The bottom and top of the channel are at z = 0, H, and the cross section is given by the quite general form -f1(z) ≤ y ≤ f2(z) for 0 ≤ z ≤ H. The flow is modeled by the one-layer shallow-water equations obtained for the time-dependent motion. We solve the problem by a finite-difference numerical code to present typical height h, velocity u, and mass fractions of particle (concentrations) (ϕ( j), j = 1, …, n) profiles. The runout length of suspensions in channels of power-law cross sections is analytically predicted using a simplified depth-averaged "box" model. We demonstrate that any degree of polydispersivity adds to the runout length of the currents, relative to that of equivalent monodisperse currents with an average settling velocity. The theoretical predictions are supported by the available experimental data. The present approach is a significant generalization of the particle-driven gravity current problem: on the one hand, now the monodisperse current in non-rectangular channels is a particular case of n = 1. On the other hand, the classical formulation of polydisperse currents for a rectangular channel is now just a particular case, f(z) = const., in the wide domain of cross sections covered by this new model.

  9. 33 CFR 117.225 - Yellow Mill Channel.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Yellow Mill Channel. 117.225 Section 117.225 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Connecticut § 117.225 Yellow Mill Channel. The...

  10. 33 CFR 117.598 - Eel Pond Channel.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Eel Pond Channel. 117.598 Section 117.598 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.598 Eel Pond Channel. The...

  11. 33 CFR 117.598 - Eel Pond Channel.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Eel Pond Channel. 117.598 Section 117.598 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.598 Eel Pond Channel. The...

  12. 33 CFR 117.598 - Eel Pond Channel.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Eel Pond Channel. 117.598 Section 117.598 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.598 Eel Pond Channel. The...

  13. 33 CFR 117.598 - Eel Pond Channel.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Eel Pond Channel. 117.598 Section 117.598 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.598 Eel Pond Channel. The...

  14. 33 CFR 117.598 - Eel Pond Channel.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Eel Pond Channel. 117.598 Section 117.598 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.598 Eel Pond Channel. The...

  15. Intermediate view synthesis algorithm using mesh clustering for rectangular multiview camera system

    NASA Astrophysics Data System (ADS)

    Choi, Byeongho; Kim, Taewan; Oh, Kwan-Jung; Ho, Yo-Sung; Choi, Jong-Soo

    2010-02-01

    A multiview video-based three-dimensional (3-D) video system offers a realistic impression and a free view navigation to the user. The efficient compression and intermediate view synthesis are key technologies since 3-D video systems deal multiple views. We propose an intermediate view synthesis using a rectangular multiview camera system that is suitable to realize 3-D video systems. The rectangular multiview camera system not only can offer free view navigation both horizontally and vertically but also can employ three reference views such as left, right, and bottom for intermediate view synthesis. The proposed view synthesis method first represents the each reference view to meshes and then finds the best disparity for each mesh element by using the stereo matching between reference views. Before stereo matching, we separate the virtual image to be synthesized into several regions to enhance the accuracy of disparities. The mesh is classified into foreground and background groups by disparity values and then affine transformed. By experiments, we confirm that the proposed method synthesizes a high-quality image and is suitable for 3-D video systems.

  16. 33 CFR 118.90 - Bridges crossing channel obliquely.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Bridges crossing channel obliquely. 118.90 Section 118.90 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.90 Bridges crossing channel obliquely. Bridges...

  17. 33 CFR 118.90 - Bridges crossing channel obliquely.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Bridges crossing channel obliquely. 118.90 Section 118.90 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.90 Bridges crossing channel obliquely. Bridges...

  18. Jetting of a shear banding fluid in rectangular ducts

    PubMed Central

    Salipante, Paul F.; Little, Charles A. E.; Hudson, Steven D.

    2017-01-01

    Non-Newtonian fluids are susceptible to flow instabilities such as shear banding, in which the fluid may exhibit a markedly discontinuous viscosity at a critical stress. Here we report the characteristics and causes of a jetting flow instability of shear banding wormlike micelle solutions in microfluidic channels with rectangular cross sections over an intermediate volumetric flow regime. Particle-tracking methods are used to measure the three-dimensional flow field in channels of differing aspect ratios, sizes, and wall materials. When jetting occurs, it is self-contained within a portion of the channel where the flow velocity is greater than the surroundings. We observe that the instability forms in channels with aspect ratio greater than 5, and that the location of the high-velocity jet appears to be sensitive to stress localizations. Jetting is not observed in a lower concentration solution without shear banding. Simulations using the Johnson-Segalman viscoelastic model show a qualitatively similar behavior to the experimental observations and indicate that compressive normal stresses in the cross-stream directions support the development of the jetting flow. Our results show that nonuniform flow of shear thinning fluids can develop across the wide dimension in rectangular microfluidic channels, with implications for microfluidic rheometry. PMID:28691108

  19. Navigation by environmental geometry: the use of zebrafish as a model.

    PubMed

    Lee, Sang Ah; Vallortigara, Giorgio; Flore, Michele; Spelke, Elizabeth S; Sovrano, Valeria A

    2013-10-01

    Sensitivity to environmental shape in spatial navigation has been found, at both behavioural and neural levels, in virtually every species tested, starting early in development. Moreover, evidence that genetic deletions can cause selective deficits in such navigation behaviours suggests a genetic basis to navigation by environmental geometry. Nevertheless, the geometric computations underlying navigation have not been specified in any species. The present study teases apart the geometric components within the traditionally used rectangular enclosure and finds that zebrafish selectively represent distance and directional relationships between extended boundary surfaces. Similar behavioural results in geometric navigation tasks with human children provide prima facie evidence for similar underlying cognitive computations and open new doors for probing the genetic foundations that give rise to these computations.

  20. 33 CFR 162.30 - Channel of Tuckerton Creek, N.J.; navigation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Channel of Tuckerton Creek, N.J.; navigation. 162.30 Section 162.30 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Tuckerton Creek, N.J.; navigation. (a) Power boats or other vessels propelled by machinery shall not proceed...

  1. 33 CFR 334.680 - Gulf of Mexico, southeast of St. Andrew Bay East Entrance, small-arms firing range, Tyndall Air...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Gulf of Mexico, southeast of St... AND RESTRICTED AREA REGULATIONS § 334.680 Gulf of Mexico, southeast of St. Andrew Bay East Entrance... the Gulf of Mexico, southeast of St. Andrew Bay East Entrance within a rectangular area beginning at a...

  2. 33 CFR 334.680 - Gulf of Mexico, southeast of St. Andrew Bay East Entrance, small-arms firing range, Tyndall Air...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Gulf of Mexico, southeast of St... AND RESTRICTED AREA REGULATIONS § 334.680 Gulf of Mexico, southeast of St. Andrew Bay East Entrance... the Gulf of Mexico, southeast of St. Andrew Bay East Entrance within a rectangular area beginning at a...

  3. 33 CFR 334.680 - Gulf of Mexico, southeast of St. Andrew Bay East Entrance, small-arms firing range, Tyndall Air...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Gulf of Mexico, southeast of St... AND RESTRICTED AREA REGULATIONS § 334.680 Gulf of Mexico, southeast of St. Andrew Bay East Entrance... the Gulf of Mexico, southeast of St. Andrew Bay East Entrance within a rectangular area beginning at a...

  4. 33 CFR 334.680 - Gulf of Mexico, southeast of St. Andrew Bay East Entrance, small-arms firing range, Tyndall Air...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Gulf of Mexico, southeast of St... AND RESTRICTED AREA REGULATIONS § 334.680 Gulf of Mexico, southeast of St. Andrew Bay East Entrance... the Gulf of Mexico, southeast of St. Andrew Bay East Entrance within a rectangular area beginning at a...

  5. 33 CFR 334.680 - Gulf of Mexico, southeast of St. Andrew Bay East Entrance, small-arms firing range, Tyndall Air...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Gulf of Mexico, southeast of St... AND RESTRICTED AREA REGULATIONS § 334.680 Gulf of Mexico, southeast of St. Andrew Bay East Entrance... the Gulf of Mexico, southeast of St. Andrew Bay East Entrance within a rectangular area beginning at a...

  6. Capillary flow enhancement in rectangular polymer microchannels with a deformable wall.

    PubMed

    Anoop, R; Sen, A K

    2015-07-01

    We report the capillary flow enhancement in rectangular polymer microchannels, when one of the channel walls is a deformable polymer membrane. We provide detailed insight into the physics of elastocapillary interaction between the capillary flow and elastic membrane, which leads to significant improvements in capillary flow performance. As liquid flows by capillary action in such channels, the deformable wall deflects inwards due to the Young-Laplace pressure drop across the liquid meniscus. This, in turn, decreases the radius of curvature of the meniscus and increases the driving capillary pressure. A theoretical model is proposed to predict the resultant increase in filling speed and rise height, respectively, in deformable horizontal and vertical microchannels having large aspect ratios. A non-dimensional parameter J, which represents the ratio of the capillary force to the mechanical restoring force, is identified to quantify the elastocapillary effects in terms of the improvement in filling speed (for J>0.238) and the condition for channel collapse (J>1). The theoretical predictions show good agreement with experimental data obtained using deformable rectangular poly(dimethylsiloxane) microchannels. Both model predictions and experimental data show that over 15% improvement in the Washburn coefficient in horizontal channels, and over 30% improvement in capillary rise height in vertical channels, are possible prior to channel collapse. The proposed technique of using deformable membranes as channel walls is a viable method for capillary flow enhancement in microfluidic devices.

  7. Application of a soft computing technique in predicting the percentage of shear force carried by walls in a rectangular channel with non-homogeneous roughness.

    PubMed

    Khozani, Zohreh Sheikh; Bonakdari, Hossein; Zaji, Amir Hossein

    2016-01-01

    Two new soft computing models, namely genetic programming (GP) and genetic artificial algorithm (GAA) neural network (a combination of modified genetic algorithm and artificial neural network methods) were developed in order to predict the percentage of shear force in a rectangular channel with non-homogeneous roughness. The ability of these methods to estimate the percentage of shear force was investigated. Moreover, the independent parameters' effectiveness in predicting the percentage of shear force was determined using sensitivity analysis. According to the results, the GP model demonstrated superior performance to the GAA model. A comparison was also made between the GP program determined as the best model and five equations obtained in prior research. The GP model with the lowest error values (root mean square error ((RMSE) of 0.0515) had the best function compared with the other equations presented for rough and smooth channels as well as smooth ducts. The equation proposed for rectangular channels with rough boundaries (RMSE of 0.0642) outperformed the prior equations for smooth boundaries.

  8. 33 CFR 117.753 - Ship Channel, Great Egg Harbor Bay.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Ship Channel, Great Egg Harbor Bay. 117.753 Section 117.753 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND..., Great Egg Harbor Bay. The draw of the S52 (Ship Channel) bridge, mile 0.5 between Somers Point and Ocean...

  9. 33 CFR 117.753 - Ship Channel, Great Egg Harbor Bay.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Ship Channel, Great Egg Harbor Bay. 117.753 Section 117.753 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND..., Great Egg Harbor Bay. The draw of the S52 (Ship Channel) bridge, mile 0.5 between Somers Point and Ocean...

  10. Analytical Model of Advection and Erosion in a Rectangular Channel

    NASA Astrophysics Data System (ADS)

    Kaufman, Miron

    2007-03-01

    We consider the Boussinesq pressure driven creeping flow in a rectangular channel. We assume a particle to be made of primary fragments bound together. Particles are advected by the flow and they erode because of the shear stresses imparted by the fluid. The time evolution of the numbers of particles of different sizes is described by the Bateman equations of nuclear radioactivity. We find, by solving these differential equations, the numbers of particles of each possible size as functions of time.

  11. Application of the Wiener-Hopf method for describing the propagation of sound in cylindrical and rectangular channels with an impedance jump in the presence of a flow

    NASA Astrophysics Data System (ADS)

    Sobolev, A. F.; Yakovets, M. A.

    2017-11-01

    Exact solutions to problems of the propagation of acoustic modes in lined channels with an impedance jump in the presence of a uniform flow are constructed. Two problems that can be solved by the Wiener- Hopf method—the propagation of acoustic modes in an infinite cylindrical channel with a transverse impedance jump and the propagation of acoustic modes in a rectangular channel with an impedance jump on one of its walls—are considered. On the channel walls, the Ingard-Myers boundary conditions are imposed and, as an additional boundary condition in the vicinity of the junction of the linings, the condition expressing the finiteness of the acoustic energy. Analytical expressions for the amplitudes of the transmitted and reflected fields are obtained.

  12. Navigation by environmental geometry: the use of zebrafish as a model

    PubMed Central

    Lee, Sang Ah; Vallortigara, Giorgio; Flore, Michele; Spelke, Elizabeth S.; Sovrano, Valeria A.

    2013-01-01

    SUMMARY Sensitivity to environmental shape in spatial navigation has been found, at both behavioural and neural levels, in virtually every species tested, starting early in development. Moreover, evidence that genetic deletions can cause selective deficits in such navigation behaviours suggests a genetic basis to navigation by environmental geometry. Nevertheless, the geometric computations underlying navigation have not been specified in any species. The present study teases apart the geometric components within the traditionally used rectangular enclosure and finds that zebrafish selectively represent distance and directional relationships between extended boundary surfaces. Similar behavioural results in geometric navigation tasks with human children provide prima facie evidence for similar underlying cognitive computations and open new doors for probing the genetic foundations that give rise to these computations. PMID:23788708

  13. 33 CFR 165.1195 - Regulated Navigation Area; Humboldt Bay Bar Channel and Humboldt Bay Entrance Channel, Humboldt...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Navigation Area (RNA) includes all navigable waters of the Humboldt Bay Bar Channel and the Humboldt Bay Entrance Channel, Humboldt Bay, California. (b) Definitions. As used in this section— COTP means the Captain of the Port as defined in Title 33, Code of Federal Regulations, Section 1.01-30 and 3.55-20...

  14. 33 CFR 165.1195 - Regulated Navigation Area; Humboldt Bay Bar Channel and Humboldt Bay Entrance Channel, Humboldt...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Navigation Area (RNA) includes all navigable waters of the Humboldt Bay Bar Channel and the Humboldt Bay Entrance Channel, Humboldt Bay, California. (b) Definitions. As used in this section— COTP means the Captain of the Port as defined in Title 33, Code of Federal Regulations, Section 1.01-30 and 3.55-20...

  15. 33 CFR 165.1195 - Regulated Navigation Area; Humboldt Bay Bar Channel and Humboldt Bay Entrance Channel, Humboldt...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Navigation Area (RNA) includes all navigable waters of the Humboldt Bay Bar Channel and the Humboldt Bay Entrance Channel, Humboldt Bay, California. (b) Definitions. As used in this section— COTP means the Captain of the Port as defined in Title 33, Code of Federal Regulations, Section 1.01-30 and 3.55-20...

  16. 33 CFR 165.1195 - Regulated Navigation Area; Humboldt Bay Bar Channel and Humboldt Bay Entrance Channel, Humboldt...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Navigation Area (RNA) includes all navigable waters of the Humboldt Bay Bar Channel and the Humboldt Bay Entrance Channel, Humboldt Bay, California. (b) Definitions. As used in this section— COTP means the Captain of the Port as defined in Title 33, Code of Federal Regulations, Section 1.01-30 and 3.55-20...

  17. 33 CFR 165.1195 - Regulated Navigation Area; Humboldt Bay Bar Channel and Humboldt Bay Entrance Channel, Humboldt...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Navigation Area (RNA) includes all navigable waters of the Humboldt Bay Bar Channel and the Humboldt Bay Entrance Channel, Humboldt Bay, California. (b) Definitions. As used in this section— COTP means the Captain of the Port as defined in Title 33, Code of Federal Regulations, Section 1.01-30 and 3.55-20...

  18. Electroosmotic flow and ionic conductance in a pH-regulated rectangular nanochannel

    NASA Astrophysics Data System (ADS)

    Sadeghi, Morteza; Saidi, Mohammad Hassan; Sadeghi, Arman

    2017-06-01

    Infinite series solutions are obtained for electrical potential, electroosmotic velocity, ionic conductance, and surface physicochemical properties of long pH-regulated rectangular nanochannels of low surface potential utilizing the double finite Fourier transform method. Closed form expressions are also obtained for channels of large height to width ratio for which the depthwise variations vanish. Neglecting the Stern layer impact, the effects of EDL (Electric Double Layer) overlap, multiple ionic species, and association/dissociation reactions on the surface are all taken into account. Moreover, finite-element-based numerical simulations are conducted to account for the end effects as well as to validate the analytical solutions. We show that, with the exception of the migratory ionic conductivity, all the physicochemical parameters are strong functions of the channel aspect ratio. Accordingly, a slit geometry is not a good representative of a rectangular channel when the width is comparable to the height. It is also observed that the distribution of the electrical potential is not uniform over the surface of a charge-regulated channel. In addition, unlike ordinary channels for which an increase in the background salt concentration is always accompanied by higher flow rates, quite the opposite may be true for a pH-regulated duct at higher salt concentrations.

  19. The orientation of homing pigeons (Columba livia f.d.) with and without navigational experience in a two-dimensional environment.

    PubMed

    Mehlhorn, Julia; Rehkaemper, Gerd

    2017-01-01

    Homing pigeons are known for their excellent homing ability, and their brains seem to be functionally adapted to homing. It is known that pigeons with navigational experience show a larger hippocampus and also a more lateralised brain than pigeons without navigational experience. So we hypothesized that experience may have an influence also on orientation ability. We examined two groups of pigeons (11 with navigational experience and 17 without) in a standard operant chamber with a touch screen monitor showing a 2-D schematic of a rectangular environment (as "geometric" information) and one uniquely shaped and colored feature in each corner (as "landmark" information). Pigeons were trained first for pecking on one of these features and then we examined their ability to encode geometric and landmark information in four tests by modifying the rectangular environment. All tests were done under binocular and monocular viewing to test hemispheric dominance. The number of pecks was counted for analysis. Results show that generally both groups orientate on the basis of landmarks and the geometry of environment, but landmark information was preferred. Pigeons with navigational experience did not perform better on the tests but showed a better conjunction of the different kinds of information. Significant differences between monocular and binocular viewing were detected particularly in pigeons without navigational experience on two tests with reduced information. Our data suggest that the conjunction of geometric and landmark information might be integrated after processing separately in each hemisphere and that this process is influenced by experience.

  20. 33 CFR 209.325 - Navigation lights, aids to navigation, navigation charts, and related data policy, practices and...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE...), will report the channel conditions promptly, using standard tabular forms, to: Director, Defense... operations in important channels in tidal waters—either in progress and not already reported, or soon to be...

  1. Present Practice of Using Nautical Depth to Manage Navigation Channels in the Presence of Fluid Mud

    DTIC Science & Technology

    2017-05-01

    material surfaces cannot be interpreted reliably unless other correlating information is developed. Surveying of fluid mud properties. At some locations...depth to manage navigation channels and ports requires a mud property that determines a navigability criteria, a practical method for surveying that...for managing navigation channels, (3) issues related to conducting hydrographic surveying in waterways with fluid mud bottoms, (4) the newest

  2. Velocity-based analysis of sediment incipient deposition in rigid boundary open channels.

    PubMed

    Aksoy, Hafzullah; Safari, Mir Jafar Sadegh; Unal, Necati Erdem; Mohammadi, Mirali

    2017-11-01

    Drainage systems must be designed in a way to minimize undesired problems such as decrease in hydraulic capacity of the channel, blockage and transport of pollutants due to deposition of sediment. Channel design considering self-cleansing criteria are used to solve the sedimentation problem. Incipient deposition is one of the non-deposition self-cleansing design criteria that can be used as a conservative method for channel design. Experimental studies have been carried out in five different cross-section channels, namely trapezoidal, rectangular, circular, U-shape and V-bottom. Experiments were performed in a tilting flume using four different sizes of sands as sediment in nine different channel bed slopes. Two well-known methods, namely the Novak & Nalluri and Yang methods are considered for the analysis of sediment motion. Equations developed using experimental data are found to be in agreement with the literature. It is concluded that the design velocity depends on the shape of the channel cross-section. Rectangular and V-bottom channels need lower and higher incipient deposition velocities, respectively, in comparison with other channels.

  3. Numerical modelling of channel processes and analysis of possible channel improvement measures on the Lena River near city Yakutsk

    NASA Astrophysics Data System (ADS)

    Krylenko, Inna; Belikov, Vitaly; Zavadskii, Aleksander; Borisova, Natalya; Golovlyov, Pavel; Rumyantsev, Alexey

    2017-04-01

    City Yakutsk (administrative, culture and industrial center of the North East of Russia) situated on the left bank of large Russian river Lena last decades has faced with many problems, concerning intensive channel processes. Most dramatic among them are sediment accumulation near main water intake structure, supplying city Yakutsk by the drinking water, and deterioration in conditions of the navigation roots to the main city ports. Hydrodynamic modelling has been chosen as the main tool for analyses of the modern tendencies in channel processes and for the evaluation of possible channel improvement measures efficiency. STREAM_2D program complex (authors V. Belikov et al.), which is based on the numerical solution of two-dimensional Saint-Venant equations on a hybrid curvilinear quadrangular and rectangular mesh and take into account sediment transport, was used for the simulations. Detailed field data about water regime of the Lena river, bathymetry of the channels and topography of the floodplains was collected for model developing. Model area has covered 75 km of the Lena river valley including branched channels and wide floodplain from Tabaga to Kangalassy gauge cites. Data of these stations were used for model boundary conditions assigning. Data of gauge station city Yakutsk as well as measured during field campaign water levels and flow velocities was taken into account for model calibration and validation. Results of modelling has demonstrated close correspondence with observed water levels and discharges distribution between channel branches for different hydrological situations. Different combinations of hydrographs of 1, 10, 50% exceedance probability was used as input for modelling of channel deformations. Simulation results has shown that in future 10 years aligning of water discharges distribution between main Lena river branches near Yakutsk is possible, that is a positive tendency from the point of view of water supply of the city. More than 15 variants of channel improvement measures, including different dam constructions, river bed dredging, closing of some river branches were considered and included into modelling scenarios. Analyses of results of modelling has allowed to reveal, that more expensive big dams which are partitioning off a part the main channel are not so effective, because their construction lead to significant increasing of flow velocities and corresponding increasing in sediment transport. Local channel regulations measures (small dam at Ponomarev island near Yakutsk and bed dredging) can give some effect in a few years due to formation of the new line of the depths maximum near water intake structure and Yakutsk port. For improving of the navigation conditions near Ghatay port closing of the small channel branch Ghataiskaya can be effective.

  4. Critical heat flux for free convection boiling in thin rectangular channels

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

    Cheng, Lap Y.; Tichler, P.R.

    A review of the experimental data on free convection boiling critical heat flux (CHF) in vertical rectangular channels reveals three mechanisms of burnout. They are the pool boiling limit, the circulation limit, and the flooding limit associated with a transition in flow regime from churn to annular flow. The dominance of a particular mechanism depends on the dimensions of the channel. Analytical models were developed for each free convection boiling limit. Limited agreement with data is observed. A CHF correlation, which is valid for a wide range of gap sizes, was constructed from the CHFs calculated according to the threemore » mechanisms of burnout. 17 refs., 7 figs.« less

  5. Design of open rectangular and trapezoidal channels

    NASA Astrophysics Data System (ADS)

    González, C. P.; Vera, P. E.; Carrillo, G.; García, S.

    2018-04-01

    In this work, the results of designing open channels in rectangular and trapezoidal form are presented. For the development of the same important aspects were taken as determination of flows by means of formula of the rational method, area of the surface for its implementation, optimal form of the flow to meet the needs of that environment. In the design the parameter of the hydraulic radius expressed in terms of the hydraulic area and wet perimeter was determined, considering that the surface on which the fluid flows is the product of the perimeter of the section and the length of the channel and where shear is generated by the condition of no slippage.

  6. Performance analysis of SOI MOSFET with rectangular recessed channel

    NASA Astrophysics Data System (ADS)

    Singh, M.; Mishra, S.; Mohanty, S. S.; Mishra, G. P.

    2016-03-01

    In this paper a two dimensional (2D) rectangular recessed channel-silicon on insulator metal oxide semiconductor field effect transistor (RRC-SOI MOSFET), using the concept of groove between source and drain regions, which is one of the channel engineering technique to suppress the short channel effect (SCE). This suppression is mainly due to corner potential barrier of the groove and the simulation is carried out by using ATLAS 2D device simulator. To have further improvement of SCE in RRC-SOI MOSFET, three more devices are designed by using dual material gate (DMG) and gate dielectric technique, which results in formation of devices i.e. DMRRC-SOI,MLSMRRC-SOI, MLDMRRC-SOI MOSFET. The effect of different structures of RRC-SOI on AC and RF parameters are investigated and the importance of these devices over RRC MOSFET regarding short channel effect is analyzed.

  7. 33 CFR 165.808 - Corpus Christi Ship Channel, Corpus Christi, TX, safety zone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Corpus Christi Ship Channel, Corpus Christi, TX, safety zone. 165.808 Section 165.808 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY REGULATED NAVIGATION AREAS AND LIMITED ACCESS AREAS Specific Regulated Navigatio...

  8. 33 CFR 165.835 - Security Zone; Port of Mobile, Mobile Ship Channel, Mobile, AL.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone; Port of Mobile, Mobile Ship Channel, Mobile, AL. 165.835 Section 165.835 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY REGULATED NAVIGATION AREAS AND LIMITED ACCESS AREAS Specific Regulated...

  9. Channel Shoaling with Deepening of Houma Navigation Channel at Cat Island Pass, Louisiana

    DTIC Science & Technology

    2011-01-01

    is, Ac (m2)=6.992x10-4P0.86 (m3) (2) The minimum cross-sectional area for Cat Island Pass has increased through time, approximately 32,100...Journal of Coastal Research SI 59 256-265 West Palm Beach, Florida 2011 Channel Shoaling with Deepening of Houma Navigation Channel at Cat ...Deepening of Houma Navigation Channel at Cat Island Pass, Louisiana. In: Roberts, T.M., Rosati, J.D., and Wang, P. (eds.), Proceedings, Symposium to Honor

  10. 75 FR 18776 - Regulated Navigation Area; Galveston Channel, TX

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-13

    ... that the proposed regulated navigation area covers a small area and vessels are allowed to travel...-AA11 Regulated Navigation Area; Galveston Channel, TX AGENCY: Coast Guard, DHS. ACTION: Notice of proposed rulemaking. SUMMARY: The Coast Guard proposes to establish a regulated navigation area across the...

  11. 33 CFR 117.751 - Shark River (South Channel).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Shark River (South Channel). 117.751 Section 117.751 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.751 Shark River (South...

  12. 33 CFR 117.751 - Shark River (South Channel).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Shark River (South Channel). 117.751 Section 117.751 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.751 Shark River (South...

  13. 33 CFR 117.751 - Shark River (South Channel).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Shark River (South Channel). 117.751 Section 117.751 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.751 Shark River (South...

  14. 33 CFR 117.751 - Shark River (South Channel).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Shark River (South Channel). 117.751 Section 117.751 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.751 Shark River (South...

  15. 33 CFR 117.751 - Shark River (South Channel).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Shark River (South Channel). 117.751 Section 117.751 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.751 Shark River (South...

  16. Single step sequential polydimethylsiloxane wet etching to fabricate a microfluidic channel with various cross-sectional geometries

    NASA Astrophysics Data System (ADS)

    Wang, C.-K.; Liao, W.-H.; Wu, H.-M.; Lo, Y.-H.; Lin, T.-R.; Tung, Y.-C.

    2017-11-01

    Polydimethylsiloxane (PDMS) has become a widely used material to construct microfluidic devices for various biomedical and chemical applications due to its desirable material properties and manufacturability. PDMS microfluidic devices are usually fabricated using soft lithography replica molding methods with master molds made of photolithogrpahy patterned photoresist layers on silicon wafers. The fabricated microfluidic channels often have rectangular cross-sectional geometries with single or multiple heights. In this paper, we develop a single step sequential PDMS wet etching process that can be used to fabricate microfluidic channels with various cross-sectional geometries from single-layer PDMS microfluidic channels. The cross-sections of the fabricated channel can be non-rectangular, and varied along the flow direction. Furthermore, the fabricated cross-sectional geometries can be numerically simulated beforehand. In the experiments, we fabricate microfluidic channels with various cross-sectional geometries using the developed technique. In addition, we fabricate a microfluidic mixer with alternative mirrored cross-sectional geometries along the flow direction to demonstrate the practical usage of the developed technique.

  17. 33 CFR 207.640 - Sacramento Deep Water Ship Channel Barge Lock and Approach Canals; use, administration, and...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Sacramento Deep Water Ship... REGULATIONS § 207.640 Sacramento Deep Water Ship Channel Barge Lock and Approach Canals; use, administration, and navigation. (a) Sacramento Deep Water Ship Channel Barge Lock and Approach Canals; use...

  18. 33 CFR 207.640 - Sacramento Deep Water Ship Channel Barge Lock and Approach Canals; use, administration, and...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Sacramento Deep Water Ship... REGULATIONS § 207.640 Sacramento Deep Water Ship Channel Barge Lock and Approach Canals; use, administration, and navigation. (a) Sacramento Deep Water Ship Channel Barge Lock and Approach Canals; use...

  19. 33 CFR 207.640 - Sacramento Deep Water Ship Channel Barge Lock and Approach Canals; use, administration, and...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Sacramento Deep Water Ship... REGULATIONS § 207.640 Sacramento Deep Water Ship Channel Barge Lock and Approach Canals; use, administration, and navigation. (a) Sacramento Deep Water Ship Channel Barge Lock and Approach Canals; use...

  20. Transition regime analytical solution to gas mass flow rate in a rectangular micro channel

    NASA Astrophysics Data System (ADS)

    Dadzie, S. Kokou; Dongari, Nishanth

    2012-11-01

    We present an analytical model predicting the experimentally observed gas mass flow rate in rectangular micro channels over slip and transition regimes without the use of any fitting parameter. Previously, Sone reported a class of pure continuum regime flows that requires terms of Burnett order in constitutive equations of shear stress to be predicted appropriately. The corrective terms to the conventional Navier-Stokes equation were named the ghost effect. We demonstrate in this paper similarity between Sone ghost effect model and newly so-called 'volume diffusion hydrodynamic model'. A generic analytical solution to gas mass flow rate in a rectangular micro channel is then obtained. It is shown that the volume diffusion hydrodynamics allows to accurately predict the gas mass flow rate up to Knudsen number of 5. This can be achieved without necessitating the use of adjustable parameters in boundary conditions or parametric scaling laws for constitutive relations. The present model predicts the non-linear variation of pressure profile along the axial direction and also captures the change in curvature with increase in rarefaction.

  1. Static response of deformable microchannels

    NASA Astrophysics Data System (ADS)

    Christov, Ivan C.; Sidhore, Tanmay C.

    2017-11-01

    Microfluidic channels manufactured from PDMS are a key component of lab-on-a-chip devices. Experimentally, rectangular microchannels are found to deform into a non-rectangular cross-section due to fluid-structure interactions. Deformation affects the flow profile, which results in a nonlinear relationship between the volumetric flow rate and the pressure drop. We develop a framework, within the lubrication approximation (l >> w >> h), to self-consistently derive flow rate-pressure drop relations. Emphasis is placed on handling different types of elastic response: from pure plate-bending, to half-space deformation, to membrane stretching. The ``simplest'' model (Stokes flow in a 3D rectangular channel capped with a linearly elastic Kirchhoff-Love plate) agrees well with recent experiments. We also simulate the static response of such microfluidic channels under laminar flow conditions using ANSYSWorkbench. Simulations are calibrated using experimental flow rate-pressure drop data from the literature. The simulations provide highly resolved deformation profiles, which are difficult to measure experimentally. By comparing simulations, experiments and our theoretical models, we show good agreement in many flow/deformation regimes, without any fitting parameters.

  2. Flow regimes of adiabatic gas-liquid two-phase under rolling conditions

    NASA Astrophysics Data System (ADS)

    Yan, Chaoxing; Yan, Changqi; Sun, Licheng; Xing, Dianchuan; Wang, Yang; Tian, Daogui

    2013-07-01

    Characteristics of adiabatic air/water two-phase flow regimes under vertical and rolling motion conditions were investigated experimentally. Test sections are two rectangular ducts with the gaps of 1.41 and 10 mm, respectively, and a circular tube with 25 mm diameter. Flow regimes were recorded by a high speed CCD-camera and were identified by examining the video images. The experimental results indicate that the characteristics of flow patterns in 10 mm wide rectangular duct under vertical condition are very similar to those in circular tube, but different from the 1.41 mm wide rectangular duct. Channel size has a significant influence on flow pattern transition, boundary of which in rectangular channels tends asymptotically towards that in the circular tube with increasing the width of narrow side. Flow patterns in rolling channels are similar to each other, nevertheless, the effect of rolling motion on flow pattern transition are significantly various. Due to the remarkable influences of the friction shear stress and surface tension in the narrow gap duct, detailed flow pattern maps of which under vertical and rolling conditions are indistinguishable. While for the circular tube with 25 mm diameter, the transition from bubbly to slug flow occurs at a higher superficial liquid velocity and the churn flow covers more area on the flow regime map as the rolling period decreases.

  3. System and method for chromatography and electrophoresis using circular optical scanning

    DOEpatents

    Balch, Joseph W.; Brewer, Laurence R.; Davidson, James C.; Kimbrough, Joseph R.

    2001-01-01

    A system and method is disclosed for chromatography and electrophoresis using circular optical scanning. One or more rectangular microchannel plates or radial microchannel plates has a set of analysis channels for insertion of molecular samples. One or more scanning devices repeatedly pass over the analysis channels in one direction at a predetermined rotational velocity and with a predetermined rotational radius. The rotational radius may be dynamically varied so as to monitor the molecular sample at various positions along a analysis channel. Sample loading robots may also be used to input molecular samples into the analysis channels. Radial microchannel plates are built from a substrate whose analysis channels are disposed at a non-parallel angle with respect to each other. A first step in the method accesses either a rectangular or radial microchannel plate, having a set of analysis channels, and second step passes a scanning device repeatedly in one direction over the analysis channels. As a third step, the scanning device is passed over the analysis channels at dynamically varying distances from a centerpoint of the scanning device. As a fourth step, molecular samples are loaded into the analysis channels with a robot.

  4. Flow field induced particle accumulation inside droplets in rectangular channels.

    PubMed

    Hein, Michael; Moskopp, Michael; Seemann, Ralf

    2015-07-07

    Particle concentration is a basic operation needed to perform washing steps or to improve subsequent analysis in many (bio)-chemical assays. In this article we present field free, hydrodynamic accumulation of particles and cells in droplets flowing within rectangular micro-channels. Depending on droplet velocity, particles either accumulate at the rear of the droplet or are dispersed over the entire droplet cross-section. We show that the observed particle accumulation behavior can be understood by a coupling of particle sedimentation to the internal flow field of the droplet. The changing accumulation patterns are explained by a qualitative change of the internal flow field. The topological change of the internal flow field, however, is explained by the evolution of the droplet shape with increasing droplet velocity altering the friction with the channel walls. In addition, we demonstrate that accumulated particles can be concentrated, removing excess dispersed phase by splitting the droplet at a simple channel junction.

  5. The effect of nozzle-exit-channel shape on resultant fiber diameter in melt-electrospinning

    NASA Astrophysics Data System (ADS)

    Esmaeilirad, Ahmad; Ko, Junghyuk; Rukosuyev, Maxym V.; Lee, Jason K.; Lee, Patrick C.; Jun, Martin B. G.

    2017-01-01

    In recent decades, electrospinning using a molten poly (ε-caprolactone) resin has gained attention for creating fibrous tissue scaffolds. The topography and diameter control of such electrospun microfibers is an important issue for their different applications in tissue engineering. Charge density, initial nozzle-exit-channel cross-sectional area, nozzle to collector distance, viscosity, and processing temperature are the most important input parameters that affect the final electrospun fiber diameters. In this paper we will show that the effect of nozzle-exit-channel shape is as important as the other effective parameters in a resultant fiber diameter. However, to the best of our knowledge, the effect of nozzle-exit-channel shapes on a resultant fiber diameter have not been studied before. Comparing rectangular and circular nozzles with almost the same exit-channel cross-sectional areas in a similar processing condition showed that using a rectangular nozzle resulted in decreasing final fiber diameter up to 50%. Furthermore, the effect of processing temperature on the final fiber topography was investigated.

  6. Heat transfer in a compact heat exchanger containing rectangular channels and using helium gas

    NASA Technical Reports Server (NTRS)

    Olson, D. A.

    1991-01-01

    Development of a National Aerospace Plane (NASP), which will fly at hypersonic speeds, require novel cooling techniques to manage the anticipated high heat fluxes on various components. A compact heat exchanger was constructed consisting of 12 parallel, rectangular channels in a flat piece of commercially pure nickel. The channel specimen was radiatively heated on the top side at heat fluxes of up to 77 W/sq cm, insulated on the back side, and cooled with helium gas flowing in the channels at 3.5 to 7.0 MPa and Reynolds numbers of 1400 to 28,000. The measured friction factor was lower than that of the accepted correlation for fully developed turbulent flow, although the uncertainty was high due to uncertainty in the channel height and a high ratio of dynamic pressure to pressure drop. The measured Nusselt number, when modified to account for differences in fluid properties between the wall and the cooling fluid, agreed with past correlations for fully developed turbulent flow in channels. Flow nonuniformity from channel-to-channel was as high as 12 pct above and 19 pct below the mean flow.

  7. Transition between free, mixed and forced convection

    NASA Astrophysics Data System (ADS)

    Jaeger, W.; Trimborn, F.; Niemann, M.; Saini, V.; Hering, W.; Stieglitz, R.; Pritz, B.; Fröhlich, J.; Gabi, M.

    2017-07-01

    In this contribution, numerical methods are discussed to predict the heat transfer to liquid metal flowing in rectangular flow channels. A correct representation of the thermo-hydraulic behaviour is necessary, because these numerical methods are used to perform design and safety studies of components with rectangular channels. Hence, it must be proven that simulation results are an adequate representation of the real conditions. Up to now, the majority of simulations are related to forced convection of liquid metals flowing in circular pipes or rod bundle, because these geometries represent most of the components in process engineering (e.g. piping, heat exchanger). Open questions related to liquid metal heat transfer, among others, is the behaviour during the transition of the heat transfer regimes. Therefore, this contribution aims to provide useful information related to the transition from forced to mixed and free convection, with the focus on a rectangular flow channel. The assessment of the thermo-hydraulic behaviour under transitional heat transfer regimes is pursued by means of system code simulations, RANS CFD simulations, LES and DNS, and experimental investigations. Thereby, each of the results will compared to the others. The comparison of external experimental data, DNS data, RANS data and system code simulation results shows that the global heat transfer can be consistently represented for forced convection in rectangular flow channels by these means. Furthermore, LES data is in agreement with RANS CFD results for different Richardson numbers with respect to temperature and velocity distribution. The agreement of the simulation results among each other and the hopefully successful validation by means of experimental data will fosters the confidence in the predicting capabilities of numerical methods, which can be applied to engineering application.

  8. Numerical Simulation of Passage of a Neutrophil through a Rectangular Channel with a Moderate Constriction

    PubMed Central

    Shirai, Atsushi; Masuda, Sunao

    2013-01-01

    The authors have previously presented a mathematical model to predict transit time of a neutrophil through an alveolar capillary segment which was modeled as an axisymmetric arc-shaped constriction settled in a cylindrical straight pipe to investigate the influence of entrance curvature of a capillary on passage of the cell. The axially asymmetric cross section of a capillary also influences the transit time because it requires three-dimensional deformation of a cell when it passes through the capillary and could lead to plasma leakage between the cell surface and the capillary wall. In this study, a rectangular channel was introduced, the side walls of which were moderately constricted, as a representative of axially asymmetric capillaries. Dependence of transit time of a neutrophil passing through the constriction on the constriction geometry, i.e., channel height, throat width and curvature radius of the constriction, was numerically investigated, the transit time being compared with that through the axisymmetric model. It was found that the transit time is dominated by the throat hydraulic diameter and curvature radius of the constriction and that the throat aspect ratio little affects the transit time with a certain limitation, indicating that if an appropriate curvature radius is chosen, such a rectangular channel model can be substituted for an axisymmetric capillary model having the same throat hydraulic diameter in terms of the transit time by choosing an appropriate curvature radius. Thus, microchannels fabricated by the photolithography technique, whose cross section is generally rectangular, are expected to be applicable to in vitro model experiments of neutrophil retention and passage in the alveolar capillaries. PMID:23527190

  9. Mixed convection in a horizontal rectangular channel - Experimental and numerical velocity distributions

    NASA Technical Reports Server (NTRS)

    Nyce, Thomas A.; Quazzani, Jalil; Durand-Daubin, Arnaud; Rosenberger, Franz

    1992-01-01

    Mixed convection in a rectangular channel (width/height = 2) with bottom-heated and top-cooled sections is studied by laser Doppler anemometry in nitrogen at Ra = 22,200 and Re = 18.75, 36, and 54. At the lower Re values, symmetry breaking is observed in steady but spatially oscillating flows that prevail over a certain distance from the leading edge of the differentially heated section. Further downstream, unsteady flows are found even for Re = 18.75. Numerical models are used to investigate the effects of adiabatic, conducting (with a conductive-convective heat transfer coefficient), and perfectly conducting side walls; channel tilts and Prandtl number dependence. Good agreement between calculations and experiment is obtained for longitudinal convective roll velocities. The transverse velocities are found to be independent of Re.

  10. Propagation and switching of light in rectangular waveguiding structures

    NASA Astrophysics Data System (ADS)

    Sala, Anca L.

    1998-10-01

    In this dissertation, we investigate the conditions for the propagation and processing of temporal optical solitons in the rectangular geometry waveguides which are expected to play an important role as processing elements in optical communication systems. It is anticipated that the optical signals carrying information through optical fibers will be in the form of temporal soliton pulses, which can propagate undistorted for long distances under the condition that the dispersion is balanced by a nonlinearity in the optical fiber. An important parameter in the equation that governs temporal soliton propagation in a waveguide is the second derivative of the propagation vector with respect to the angular frequency, /omega, denoted by β/prime'. We evaluate β/prime' for rectangular waveguides using a channel model of the waveguide, which takes into account the two transverse dimensions of the rectangular channel. Significant differences are found in the values of β/prime' obtained from our model and those obtained from the more traditional, one dimensional slab model. A major additional effort in the present thesis relates to the development of a theory of temporal soliton switching in a planar geometry nonlinear directional coupler. The theory is formulated in terms of the supermodes of the total structure, and again accounts for the two transverse dimensions of the channels. To accurately determine the coupling length and switching power of the nonlinear coupler, we apply corrections to the propagation constants of the supermodes that account for the non-zero electromagnetic fields in the outer corner regions of the waveguide channels. It is shown for the case of a SiO2 based nonlinear directional coupler operating at the central wavelength of 1.55 μm, that these corrections have a significant effect on both the coupling length and the switching power. Finally, we develop the conditions under which single mode rectangular waveguides can have zero dispersion at the optical communications wavelengths 1.31 μm or 1.55 μm, and discuss the end-to-end coupling of rectangular waveguides to the standard optical fibers used in optical communications. Our results are expected to serve as a guide for the design of planar geometry based processing elements in a variety of optical communications devices.

  11. 33 CFR 66.10-15 - Aids to navigation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... solid colored buoy. A buoy which marks the left side of the channel viewed looking upstream or toward... channel, solid colored buoys shall be established in pairs, one on each side of the navigable channel... that the user should pass between the buoys. (c) On an irregularly defined channel, solid colored buoys...

  12. 33 CFR 66.10-15 - Aids to navigation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... solid colored buoy. A buoy which marks the left side of the channel viewed looking upstream or toward... channel, solid colored buoys shall be established in pairs, one on each side of the navigable channel... that the user should pass between the buoys. (c) On an irregularly defined channel, solid colored buoys...

  13. 33 CFR 66.10-15 - Aids to navigation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... solid colored buoy. A buoy which marks the left side of the channel viewed looking upstream or toward... channel, solid colored buoys shall be established in pairs, one on each side of the navigable channel... that the user should pass between the buoys. (c) On an irregularly defined channel, solid colored buoys...

  14. 33 CFR 117.753 - Ship Channel, Great Egg Harbor Bay.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Ship Channel, Great Egg Harbor... SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.753 Ship Channel, Great Egg Harbor Bay. The draw of the S52 (Ship Channel) bridge, mile 0.5 between Somers Point and Ocean...

  15. 33 CFR 117.753 - Ship Channel, Great Egg Harbor Bay.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Ship Channel, Great Egg Harbor... SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.753 Ship Channel, Great Egg Harbor Bay. The draw of the S52 (Ship Channel) bridge, mile 0.5 between Somers Point and Ocean...

  16. 33 CFR 117.721 - Grassy Sound Channel.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Grassy Sound Channel. 117.721... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.721 Grassy Sound Channel. The draw of the Grassy Sound Channel Bridge, mile 1.0 in Middle Township, shall open on signal from 6 a.m. to 8 p...

  17. 33 CFR 117.721 - Grassy Sound Channel.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Grassy Sound Channel. 117.721... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.721 Grassy Sound Channel. The draw of the Grassy Sound Channel Bridge, mile 1.0 in Middle Township, shall open on signal from 6 a.m. to 8 p...

  18. 33 CFR 117.721 - Grassy Sound Channel.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Grassy Sound Channel. 117.721... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.721 Grassy Sound Channel. The draw of the Grassy Sound Channel Bridge, mile 1.0 in Middle Township, shall open on signal from 6 a.m. to 8 p...

  19. 33 CFR 117.721 - Grassy Sound Channel.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Grassy Sound Channel. 117.721... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.721 Grassy Sound Channel. The draw of the Grassy Sound Channel Bridge, mile 1.0 in Middle Township, shall open on signal from 6 a.m. to 8 p...

  20. 33 CFR 117.721 - Grassy Sound Channel.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Grassy Sound Channel. 117.721... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.721 Grassy Sound Channel. The draw of the Grassy Sound Channel Bridge, mile 1.0 in Middle Township, shall open on signal from 6 a.m. to 8 p...

  1. Turbulent flow and heat transfer of Water/Al2O3 nanofluid inside a rectangular ribbed channel

    NASA Astrophysics Data System (ADS)

    Parsaiemehr, Mohammad; Pourfattah, Farzad; Akbari, Omid Ali; Toghraie, Davood; Sheikhzadeh, Ghanbarali

    2018-02-01

    In present study, the turbulent flow and heat transfer of Water/Al2O3 nanofluid inside a rectangular channel have been numerically simulated. The main purpose of present study is investigating the effect of attack angle of inclined rectangular rib, Reynolds number and volume fraction of nanoparticles on heat transfer enhancement. For this reason, the turbulent flow of nanofluid has been simulated at Reynolds numbers ranging from 15000 to 30000 and volume fractions of nanoparticles from 0 to 4%. The changes attack angle of ribs have been investigated ranging from 0 to 180°. The results show that, the changes of attack angle of ribs, due to the changes of flow pattern and created vortexes inside the channel, have significant effect on fluid mixing. Also, the maximum rate of heat transfer enhancement accomplishes in attack angle of 60°. In Reynolds numbers of 15000, 20000 and 30000 and attack angle of 60°, comparing to the attack angle of 0°, the amount of Nusselt number enhances to 2.37, 1.96 and 2 times, respectively. Also, it can be concluded that, in high Reynolds numbers, by using ribs and nanofluid, the performance evaluation criterion improves.

  2. Study of proton radiation effects among diamond and rectangular gate MOSFET layouts

    NASA Astrophysics Data System (ADS)

    Seixas, L. E., Jr.; Finco, S.; Silveira, M. A. G.; Medina, N. H.; Gimenez, S. P.

    2017-01-01

    This paper describes an experimental comparative study of proton ionizing radiation effects between the metal-oxide-semiconductor (MOS) Field Effect Transistors (MOSFETs) implemented with hexagonal gate shapes (diamond) and their respective counterparts designed with the classical rectangular ones, regarding the same gate areas, channel widths and geometrical ratios (W/L). The devices were manufactured by using the 350 nm bulk complementary MOS (CMOS) integrated circuits technology. The diamond MOSFET with α angles higher or equal to 90° tends to present a smaller vulnerability to the high doses ionizing radiation than those observed in the typical rectangular MOSFET counterparts.

  3. Electroosmotic flow in a rectangular channel with variable wall zeta-potential: comparison of numerical simulation with asymptotic theory.

    PubMed

    Datta, Subhra; Ghosal, Sandip; Patankar, Neelesh A

    2006-02-01

    Electroosmotic flow in a straight micro-channel of rectangular cross-section is computed numerically for several situations where the wall zeta-potential is not constant but has a specified spatial variation. The results of the computation are compared with an earlier published asymptotic theory based on the lubrication approximation: the assumption that any axial variations take place on a long length scale compared to a characteristic channel width. The computational results are found to be in excellent agreement with the theory even when the scale of axial variations is comparable to the channel width. In the opposite limit when the wavelength of fluctuations is much shorter than the channel width, the lubrication theory fails to describe the solution either qualitatively or quantitatively. In this short wave limit the solution is well described by Ajdari's theory for electroosmotic flow between infinite parallel plates (Ajdari, A., Phys. Rev. E 1996, 53, 4996-5005.) The infinitely thin electric double layer limit is assumed in the theory as well as in the simulation.

  4. Gas turbine row #1 steam cooled vane

    DOEpatents

    Cunha, Frank J.

    2000-01-01

    A design for a vane segment having a closed-loop steam cooling system is provided. The vane segment comprises an outer shroud, an inner shroud and an airfoil, each component having a target surface on the inside surface of its walls. A plurality of rectangular waffle structures are provided on the target surface to enhance heat transfer between each component and cooling steam. Channel systems are provided in the shrouds to improve the flow of steam through the shrouds. Insert legs located in cavities in the airfoil are also provided. Each insert leg comprises outer channels located on a perimeter of the leg, each outer channel having an outer wall and impingement holes on the outer wall for producing impingement jets of cooling steam to contact the airfoil's target surface. Each insert leg further comprises a plurality of substantially rectangular-shaped ribs located on the outer wall and a plurality of openings located between outer channels of the leg to minimize cross flow degradation.

  5. Flow reversal and thermal limit in a heated rectangular channel

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

    Cheng, L.Y.; Tichler, P.R.; Yang, B.W.

    The thermal limit in a vertical rectangular channel was determined in a series of experiments whereby the internal coolant underwent a change in flow direction from forced downflow to upward natural circulation. The tests were designed to simulate the flow reversal transient in the High Flux Beam Reactor. A number of parameters were varied in the flow reversal experiments to examine their effects on the thermal limit. Among the parameters varied were the rate of flow coastdown, inlet subcooling, water level in the upper plenum, bypass ratio (ratio of initial flow through the heated section to initial flow through themore » bypass orifice), and single- verses double-sided heating.« less

  6. 33 CFR 162.205 - Suisun Bay, San Joaquin River, Sacramento River, and connecting waters, CA.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., Sacramento River, and connecting waters, CA. 162.205 Section 162.205 Navigation and Navigable Waters COAST... NAVIGATION REGULATIONS § 162.205 Suisun Bay, San Joaquin River, Sacramento River, and connecting waters, CA. (a) San Joaquin River Deep Water Channel between Suisun Bay and the easterly end of the channel at...

  7. 33 CFR 162.205 - Suisun Bay, San Joaquin River, Sacramento River, and connecting waters, CA.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., Sacramento River, and connecting waters, CA. 162.205 Section 162.205 Navigation and Navigable Waters COAST... NAVIGATION REGULATIONS § 162.205 Suisun Bay, San Joaquin River, Sacramento River, and connecting waters, CA. (a) San Joaquin River Deep Water Channel between Suisun Bay and the easterly end of the channel at...

  8. 33 CFR 162.205 - Suisun Bay, San Joaquin River, Sacramento River, and connecting waters, CA.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., Sacramento River, and connecting waters, CA. 162.205 Section 162.205 Navigation and Navigable Waters COAST... NAVIGATION REGULATIONS § 162.205 Suisun Bay, San Joaquin River, Sacramento River, and connecting waters, CA. (a) San Joaquin River Deep Water Channel between Suisun Bay and the easterly end of the channel at...

  9. 33 CFR 165.821 - Ohio River at Cincinnati, OH; regulated navigation area.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... regulated navigation area (RNA)—The waters of the Ohio River between mile 466.0 and mile 473.0. (b.... (1) Transit through the RNA by all downbound vessels towing cargoes regulated by Title 46 Code of... navigation channel of the RNA. (3) All commercial vessels shall continually monitor VHF-FM channel 13 on...

  10. 33 CFR 165.821 - Ohio River at Cincinnati, OH; regulated navigation area.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... regulated navigation area (RNA)—The waters of the Ohio River between mile 466.0 and mile 473.0. (b.... (1) Transit through the RNA by all downbound vessels towing cargoes regulated by Title 46 Code of... navigation channel of the RNA. (3) All commercial vessels shall continually monitor VHF-FM channel 13 on...

  11. 33 CFR 165.821 - Ohio River at Cincinnati, OH; regulated navigation area.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... regulated navigation area (RNA)—The waters of the Ohio River between mile 466.0 and mile 473.0. (b.... (1) Transit through the RNA by all downbound vessels towing cargoes regulated by Title 46 Code of... navigation channel of the RNA. (3) All commercial vessels shall continually monitor VHF-FM channel 13 on...

  12. 33 CFR 165.821 - Ohio River at Cincinnati, OH; regulated navigation area.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... regulated navigation area (RNA)—The waters of the Ohio River between mile 466.0 and mile 473.0. (b.... (1) Transit through the RNA by all downbound vessels towing cargoes regulated by Title 46 Code of... navigation channel of the RNA. (3) All commercial vessels shall continually monitor VHF-FM channel 13 on...

  13. 33 CFR 165.821 - Ohio River at Cincinnati, OH; regulated navigation area.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... regulated navigation area (RNA)—The waters of the Ohio River between mile 466.0 and mile 473.0. (b.... (1) Transit through the RNA by all downbound vessels towing cargoes regulated by Title 46 Code of... navigation channel of the RNA. (3) All commercial vessels shall continually monitor VHF-FM channel 13 on...

  14. 33 CFR 148.215 - What if a port has plans for a deep draft channel and harbor?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... deep draft channel and harbor? 148.215 Section 148.215 Navigation and Navigable Waters COAST GUARD... General § 148.215 What if a port has plans for a deep draft channel and harbor? (a) If a State port will... draft channel and harbor, a representative of the port may request a determination under 33 U.S.C. 1503...

  15. 33 CFR 165.508 - Security Zone; Georgetown Channel, Potomac River, Washington, DC.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., Potomac River, Washington, DC. 165.508 Section 165.508 Navigation and Navigable Waters COAST GUARD... § 165.508 Security Zone; Georgetown Channel, Potomac River, Washington, DC. (a) Definitions. (1) The... zone: All waters of the Georgetown Channel of the Potomac River, from the surface to the bottom, 75...

  16. 33 CFR 165.508 - Security Zone; Georgetown Channel, Potomac River, Washington, DC.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., Potomac River, Washington, DC. 165.508 Section 165.508 Navigation and Navigable Waters COAST GUARD... § 165.508 Security Zone; Georgetown Channel, Potomac River, Washington, DC. (a) Definitions. (1) The... zone: All waters of the Georgetown Channel of the Potomac River, from the surface to the bottom, 75...

  17. 33 CFR 165.508 - Security Zone; Georgetown Channel, Potomac River, Washington, DC.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., Potomac River, Washington, DC. 165.508 Section 165.508 Navigation and Navigable Waters COAST GUARD... § 165.508 Security Zone; Georgetown Channel, Potomac River, Washington, DC. (a) Definitions. (1) The... zone: All waters of the Georgetown Channel of the Potomac River, from the surface to the bottom, 75...

  18. 33 CFR 165.508 - Security Zone; Georgetown Channel, Potomac River, Washington, DC.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., Potomac River, Washington, DC. 165.508 Section 165.508 Navigation and Navigable Waters COAST GUARD... § 165.508 Security Zone; Georgetown Channel, Potomac River, Washington, DC. (a) Definitions. (1) The... zone: All waters of the Georgetown Channel of the Potomac River, from the surface to the bottom, 75...

  19. 33 CFR 165.508 - Security Zone; Georgetown Channel, Potomac River, Washington, DC.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., Potomac River, Washington, DC. 165.508 Section 165.508 Navigation and Navigable Waters COAST GUARD... § 165.508 Security Zone; Georgetown Channel, Potomac River, Washington, DC. (a) Definitions. (1) The... zone: All waters of the Georgetown Channel of the Potomac River, from the surface to the bottom, 75...

  20. Is There a Geometric Module for Spatial Orientation? Insights from a Rodent Navigation Model

    ERIC Educational Resources Information Center

    Sheynikhovich, Denis; Chavarriaga, Ricardo; Strosslin, Thomas; Arleo, Angelo; Gerstner, Wulfram

    2009-01-01

    Modern psychological theories of spatial cognition postulate the existence of a geometric module for reorientation. This concept is derived from experimental data showing that in rectangular arenas with distinct landmarks in the corners, disoriented rats often make diagonal errors, suggesting their preference for the geometric (arena shape) over…

  1. Cognitive Effects of Language on Human Navigation

    ERIC Educational Resources Information Center

    Shusterman, Anna; Ah Lee, Sang; Spelke, Elizabeth S.

    2011-01-01

    Language has been linked to spatial representation and behavior in humans, but the nature of this effect is debated. Here, we test whether simple verbal expressions improve 4-year-old children's performance in a disoriented search task in a small rectangular room with a single red landmark wall. Disoriented children's landmark-guided search for a…

  2. High Quality Facade Segmentation Based on Structured Random Forest, Region Proposal Network and Rectangular Fitting

    NASA Astrophysics Data System (ADS)

    Rahmani, K.; Mayer, H.

    2018-05-01

    In this paper we present a pipeline for high quality semantic segmentation of building facades using Structured Random Forest (SRF), Region Proposal Network (RPN) based on a Convolutional Neural Network (CNN) as well as rectangular fitting optimization. Our main contribution is that we employ features created by the RPN as channels in the SRF.We empirically show that this is very effective especially for doors and windows. Our pipeline is evaluated on two datasets where we outperform current state-of-the-art methods. Additionally, we quantify the contribution of the RPN and the rectangular fitting optimization on the accuracy of the result.

  3. New model for burnout prediction in channels of various cross-section

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

    Bobkov, V.P.; Kozina, N.V.; Vinogrado, V.N.

    1995-09-01

    The model developed to predict a critical heat flux (CHF) in various channels is presented together with the results of data analysis. A model is the realization of relative method of CHF describing based on the data for round tube and on the system of correction factors. The results of data description presented here are for rectangular and triangular channels, annuli and rod bundles.

  4. Neutronic reactor

    DOEpatents

    Lewis, Warren R.

    1978-05-30

    A graphite-moderated, water-cooled nuclear reactor including a plurality of rectangular graphite blocks stacked in abutting relationship in layers, alternate layers having axes which are normal to one another, alternate rows of blocks in alternate layers being provided with a channel extending through the blocks, said channeled blocks being provided with concave sides and having smaller vertical dimensions than adjacent blocks in the same layer, there being nuclear fuel in the channels.

  5. Aquatic habitat change in the Arkansas river after the development of a lock-and-dam commercial navigation system

    USGS Publications Warehouse

    Schramm, H.L.; Minnis, R.B.; Spencer, A.B.; Theel, R.T.

    2008-01-01

    The McClellan-Kerr Arkansas River Navigation System (MKARNS), completed in 1971, required the construction of 17 locks and dams and associated navigation works to make the Arkansas and Verdigris Rivers navigable for barge traffic from the Mississippi River to Catoosa, Oklahoma. We used a Geographic Information System to assess habitat changes in the 477-km portion of this system within Arkansas from 1973 to 1999. Total aquatic area declined by 9% from 42 404 to 38 655 ha. Aquatic habitat losses were 1-17% among pools. Greatest habitat losses occurred in diked secondary channels (former secondary channels with flow reduced by rock dikes) and backwaters adjacent to the main channel. Most of the area of dike pools (aquatic habitat downstream of rock dikes), diked secondary channels and adjacent backwaters were <0.9 m deep. Copyright ?? 2008 John Wiley & Sons, Ltd.

  6. 33 CFR 110.84 - Black Rock Channel opposite foot of Porter Avenue, Buffalo, N.Y.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Black Rock Channel opposite foot..., DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.84 Black Rock Channel opposite foot of Porter Avenue, Buffalo, N.Y. An area extending northwesterly between Black Rock...

  7. 33 CFR 110.84 - Black Rock Channel opposite foot of Porter Avenue, Buffalo, N.Y.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Black Rock Channel opposite foot..., DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.84 Black Rock Channel opposite foot of Porter Avenue, Buffalo, N.Y. An area extending northwesterly between Black Rock...

  8. 33 CFR 110.84 - Black Rock Channel opposite foot of Porter Avenue, Buffalo, N.Y.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Black Rock Channel opposite foot..., DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.84 Black Rock Channel opposite foot of Porter Avenue, Buffalo, N.Y. An area extending northwesterly between Black Rock...

  9. 33 CFR 110.84 - Black Rock Channel opposite foot of Porter Avenue, Buffalo, N.Y.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Black Rock Channel opposite foot..., DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.84 Black Rock Channel opposite foot of Porter Avenue, Buffalo, N.Y. An area extending northwesterly between Black Rock...

  10. 33 CFR 165.731 - Safety/Security Zone: Cumberland Sound, Georgia and St. Marys River Entrance Channel.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Sound, Georgia and St. Marys River Entrance Channel. 165.731 Section 165.731 Navigation and Navigable... Seventh Coast Guard District § 165.731 Safety/Security Zone: Cumberland Sound, Georgia and St. Marys River... waters and land from bank to bank within Cumberland Sound and the St. Marys Entrance Channel: the...

  11. 33 CFR 165.835 - Security Zone; Port of Mobile, Mobile Ship Channel, Mobile, AL.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., Mobile Ship Channel, Mobile, AL. 165.835 Section 165.835 Navigation and Navigable Waters COAST GUARD... § 165.835 Security Zone; Port of Mobile, Mobile Ship Channel, Mobile, AL. (a) Definition. As used in this section— Cruise ship means a passenger vessel over 100 gross tons, carrying more than 12...

  12. 33 CFR 165.835 - Security Zone; Port of Mobile, Mobile Ship Channel, Mobile, AL.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., Mobile Ship Channel, Mobile, AL. 165.835 Section 165.835 Navigation and Navigable Waters COAST GUARD... § 165.835 Security Zone; Port of Mobile, Mobile Ship Channel, Mobile, AL. (a) Definition. As used in this section— Cruise ship means a passenger vessel over 100 gross tons, carrying more than 12...

  13. 33 CFR 165.835 - Security Zone; Port of Mobile, Mobile Ship Channel, Mobile, AL.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., Mobile Ship Channel, Mobile, AL. 165.835 Section 165.835 Navigation and Navigable Waters COAST GUARD... § 165.835 Security Zone; Port of Mobile, Mobile Ship Channel, Mobile, AL. (a) Definition. As used in this section— Cruise ship means a passenger vessel over 100 gross tons, carrying more than 12...

  14. 33 CFR 165.835 - Security Zone; Port of Mobile, Mobile Ship Channel, Mobile, AL.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., Mobile Ship Channel, Mobile, AL. 165.835 Section 165.835 Navigation and Navigable Waters COAST GUARD... § 165.835 Security Zone; Port of Mobile, Mobile Ship Channel, Mobile, AL. (a) Definition. As used in this section— Cruise ship means a passenger vessel over 100 gross tons, carrying more than 12...

  15. 33 CFR 162.260 - Channel leading to San Juan Harbor, P.R.; use, administration, and navigation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., and navigation. (a) Steamers passing dredge engaged in improving the channel shall not have a speed... dredge anchors. (b) Vessels using the channel shall pass the dredge on the side designated from the dredge by the signals prescribed in paragraph (c) of this section. (c) Dredge shall display the red flag...

  16. 33 CFR 162.260 - Channel leading to San Juan Harbor, P.R.; use, administration, and navigation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., and navigation. (a) Steamers passing dredge engaged in improving the channel shall not have a speed... dredge anchors. (b) Vessels using the channel shall pass the dredge on the side designated from the dredge by the signals prescribed in paragraph (c) of this section. (c) Dredge shall display the red flag...

  17. Spontaneous rise in open rectangular channels under gravity.

    PubMed

    Thammanna Gurumurthy, Vignesh; Roisman, Ilia V; Tropea, Cameron; Garoff, Stephen

    2018-05-17

    Fluid movement in microfluidic devices, porous media, and textured surfaces involves coupled flows over the faces and corners of the media. Spontaneous wetting of simple grooved surfaces provides a model system to probe these flows. This numerical study investigates the spontaneous rise of a liquid in an array of open rectangular channels under gravity, using the Volume-of-Fluid method with adaptive mesh refinement. The rise is characterized by the meniscus height at the channel center, outer face and the interior and exterior corners. At lower contact angles and higher channel aspect ratios, the statics and dynamics of the rise in the channel center show little deviation with the classical model for capillarity, which ignores the existence of corners. For contact angles smaller than 45°, rivulets are formed in the interior corners and a cusp at the exterior corner. The rivulets at long times obey the one-third power law in time, with a weak dependence on the geometry. The cusp behaviour at the exterior corner transforms into a smooth meniscus when the capillary force is higher in the channel, even for contact angles smaller than 45°. The width of the outer face does not influence the capillary rise inside the channel, and the channel size does not influence the rise on the outer face. Copyright © 2018 Elsevier Inc. All rights reserved.

  18. Sediment Transport into the Swinomish Navigation Channel, Puget Sound—Habitat Restoration versus Navigation Maintenance Needs

    DOE PAGES

    Khangaonkar, Tarang; Nugraha, Adi; Hinton, Steve; ...

    2017-04-21

    The 11 mile (1.6 km) Swinomish Federal Navigation Channel provides a safe and short passage to fishing and recreational craft in and out of Northern Puget Sound by connecting Skagit and Padilla Bays, US State abbrev., USA. A network of dikes and jetties were constructed through the Swinomish corridor between 1893 and 1936 to improve navigation functionality. Over the years, these river training dikes and jetties designed to minimize sedimentation in the channel have deteriorated, resulting in reduced protection of the channel. The need to repair or modify dikes/jetties for channel maintenance, however, may conflict with salmon habitat restoration goalsmore » aimed at improving access, connectivity and brackish water habitat. Several restoration projects have been proposed in the Skagit delta involving breaching, lowering, or removal of dikes. To assess relative merits of the available alternatives, a hydrodynamic model of the Skagit River estuary was developed using the Finite Volume Community Ocean Model (FVCOM). Here, in this paper, we present the refinement and calibration of the model using oceanographic data collected from the years 2006 and 2009 with a focus on the sediment and brackish water transport from the river and Skagit Bay tide flats to the Swinomish Channel. The model was applied to assess the feasibility of achieving the desired dual outcome of (a) reducing sedimentation and shoaling in the Swinomish Channel and (b) providing a direct migration pathway and improved conveyance of freshwater into the Swinomish Channel. Finally, the potential reduction in shoaling through site-specific structure repairs is evaluated. Similarly, the potential to significantly improve of brackish water habitat through dike breach restoration actions using the McGlinn Causeway project example, along with its impacts on sediment deposition in the Swinomish Navigation Channel, is examined« less

  19. Sediment Transport into the Swinomish Navigation Channel, Puget Sound—Habitat Restoration versus Navigation Maintenance Needs

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

    Khangaonkar, Tarang; Nugraha, Adi; Hinton, Steve

    The 11 mile (1.6 km) Swinomish Federal Navigation Channel provides a safe and short passage to fishing and recreational craft in and out of Northern Puget Sound by connecting Skagit and Padilla Bays, US State abbrev., USA. A network of dikes and jetties were constructed through the Swinomish corridor between 1893 and 1936 to improve navigation functionality. Over the years, these river training dikes and jetties designed to minimize sedimentation in the channel have deteriorated, resulting in reduced protection of the channel. The need to repair or modify dikes/jetties for channel maintenance, however, may conflict with salmon habitat restoration goalsmore » aimed at improving access, connectivity and brackish water habitat. Several restoration projects have been proposed in the Skagit delta involving breaching, lowering, or removal of dikes. To assess relative merits of the available alternatives, a hydrodynamic model of the Skagit River estuary was developed using the Finite Volume Community Ocean Model (FVCOM). Here, in this paper, we present the refinement and calibration of the model using oceanographic data collected from the years 2006 and 2009 with a focus on the sediment and brackish water transport from the river and Skagit Bay tide flats to the Swinomish Channel. The model was applied to assess the feasibility of achieving the desired dual outcome of (a) reducing sedimentation and shoaling in the Swinomish Channel and (b) providing a direct migration pathway and improved conveyance of freshwater into the Swinomish Channel. Finally, the potential reduction in shoaling through site-specific structure repairs is evaluated. Similarly, the potential to significantly improve of brackish water habitat through dike breach restoration actions using the McGlinn Causeway project example, along with its impacts on sediment deposition in the Swinomish Navigation Channel, is examined« less

  20. 33 CFR 66.10-1 - General.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS..., the Uniform State Waterway Marking System's (USWMS) aids to navigation provisions for marking channels... waters for private aids to navigation and in those internal waters that are non-navigable waters of the U...

  1. 33 CFR 165.827 - Regulated Navigation Area; Galveston Channel, TX.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Regulated Navigation Area... HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY REGULATED NAVIGATION AREAS AND LIMITED ACCESS AREAS Specific Regulated Navigation Areas and Limited Access Areas Eighth Coast Guard District § 165.827...

  2. 33 CFR 165.827 - Regulated Navigation Area; Galveston Channel, TX.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Regulated Navigation Area... HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY REGULATED NAVIGATION AREAS AND LIMITED ACCESS AREAS Specific Regulated Navigation Areas and Limited Access Areas Eighth Coast Guard District § 165.827...

  3. 33 CFR 66.10-1 - General.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS..., the Uniform State Waterway Marking System's (USWMS) aids to navigation provisions for marking channels... waters for private aids to navigation and in those internal waters that are non-navigable waters of the U...

  4. Emancipating traditional channel network types: quantification of topology and geometry, and relation to geologic boundary conditions

    NASA Astrophysics Data System (ADS)

    Temme, A.; Langston, A. L.

    2017-12-01

    Traditional classification of channel networks is helpful for qualitative geologic and geomorphic inference. For instance, a dendritic network indicates no strong lithological control on where channels flow. However, an approach where channel network structure is quantified, is required to be able to indicate for instance how increasing levels of lithological control lead, gradually or suddenly, to a trellis-type drainage network Our contribution aims to aid this transition to a quantitative analysis of channel networks. First, to establish the range of typically occurring channel network properties, we selected 30 examples of traditional drainage network types from around the world. For each of these, we calculated a set of topological and geometric properties, such as total drainage length, average length of a channel segment and the average angle of intersection of channel segments. A decision tree was used to formalize the relation between these newly quantified properties on the one hand, and traditional network types on the other hand. Then, to explore how variations in lithological and geomorphic boundary conditions affect channel network structure, we ran a set of experiments with landscape evolution model Landlab. For each simulated channel network, the same set of topological and geometric properties was calculated as for the 30 real-world channel networks. The latter were used for a first, visual evaluation to find out whether a simulated network that looked, for instance, rectangular, also had the same set of properties as real-world rectangular channel networks. Ultimately, the relation between these properties and the imposed lithological and geomorphic boundary conditions was explored using simple bivariate statistics.

  5. Electro-osmotic flow in a rotating rectangular microchannel

    PubMed Central

    Ng, Chiu-On; Qi, Cheng

    2015-01-01

    An analytical model is presented for low-Rossby-number electro-osmotic flow in a rectangular channel rotating about an axis perpendicular to its own. The flow is driven under the combined action of Coriolis, pressure, viscous and electric forces. Analytical solutions in the form of eigenfunction expansions are developed for the problem, which is controlled by the rotation parameter (or the inverse Ekman number), the Debye parameter, the aspect ratio of the channel and the distribution of zeta potentials on the channel walls. Under the conditions of fast rotation and a thin electric double layer (EDL), an Ekman–EDL develops on the horizontal walls. This is essentially an Ekman layer subjected to electrokinetic effects. The flow structure of this boundary layer as a function of the Ekman layer thickness normalized by the Debye length is investigated in detail in this study. It is also shown that the channel rotation may have qualitatively different effects on the flow rate, depending on the channel width and the zeta potential distributions. Axial and secondary flows are examined in detail to reveal how the development of a geostrophic core may lead to a rise or fall of the mean flow. PMID:26345088

  6. Study of design and technology factors influencing gas turbine blade cooling

    NASA Astrophysics Data System (ADS)

    Shevchenko, I. V.; Garanin, I. V.; Rogalev, A. N.; Kindra, V. O.; Khudyakova, V. P.

    2017-11-01

    The knowledge of aerodynamic and thermal parameters of turbulators used in order to design an efficient blade cooling system. However, all experimental tests of the hydraulic and thermal characteristics of the turbulators were conducted on the rectangular shape channels with a strongly defined air flow direction. The actual blades have geometry of the channels that essentially differs from the rectangular shape. Specifically, the air flow in the back cavity of a blade with one and half-pass cooling channel changes its direction throughout the feather height. In most cases the ribs and pins are made with a tilt to the channel walls, which is determined by the moving element design of a mould for the ceramic rod element fabrication. All of the factors described above may result in the blade thermohydraulic model being developed failing to fully simulate the air flow and the heat exchange processes in some sections of the cooling path. Hence, the design temperature field will differ from the temperature field of an actual blade. This article studied the numerical data of design and technology factors influencing heat transfer in the cooling channels. The results obtained showed their substantial impact on the blade cooling efficiency.

  7. 33 CFR 66.10-1 - General.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS... Marking System's (USWMS) aids to navigation provisions for marking channels and obstructions (see § 66.10... private aids to navigation and in those internal waters that are non-navigable waters of the U.S. All...

  8. 33 CFR 66.10-1 - General.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS... Marking System's (USWMS) aids to navigation provisions for marking channels and obstructions (see § 66.10... private aids to navigation and in those internal waters that are non-navigable waters of the U.S. All...

  9. 33 CFR 66.10-1 - General.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS... Marking System's (USWMS) aids to navigation provisions for marking channels and obstructions (see § 66.10... private aids to navigation and in those internal waters that are non-navigable waters of the U.S. All...

  10. Numerical Investigation of Heat Transfer Enhancement in a Rectangular Heated Pipe for Turbulent Nanofluid

    PubMed Central

    Kazi, Salim Newaz; Sadeghinezhad, Emad

    2014-01-01

    Thermal characteristics of turbulent nanofluid flow in a rectangular pipe have been investigated numerically. The continuity, momentum, and energy equations were solved by means of a finite volume method (FVM). The symmetrical rectangular channel is heated at the top and bottom at a constant heat flux while the sides walls are insulated. Four different types of nanoparticles Al2O3, ZnO, CuO, and SiO2 at different volume fractions of nanofluids in the range of 1% to 5% are considered in the present investigation. In this paper, effect of different Reynolds numbers in the range of 5000 < Re < 25000 on heat transfer characteristics of nanofluids flowing through the channel is investigated. The numerical results indicate that SiO2-water has the highest Nusselt number compared to other nanofluids while it has the lowest heat transfer coefficient due to low thermal conductivity. The Nusselt number increases with the increase of the Reynolds number and the volume fraction of nanoparticles. The results of simulation show a good agreement with the existing experimental correlations. PMID:25254236

  11. Numerical investigation of heat transfer enhancement in a rectangular heated pipe for turbulent nanofluid.

    PubMed

    Yarmand, Hooman; Gharehkhani, Samira; Kazi, Salim Newaz; Sadeghinezhad, Emad; Safaei, Mohammad Reza

    2014-01-01

    Thermal characteristics of turbulent nanofluid flow in a rectangular pipe have been investigated numerically. The continuity, momentum, and energy equations were solved by means of a finite volume method (FVM). The symmetrical rectangular channel is heated at the top and bottom at a constant heat flux while the sides walls are insulated. Four different types of nanoparticles Al2O3, ZnO, CuO, and SiO2 at different volume fractions of nanofluids in the range of 1% to 5% are considered in the present investigation. In this paper, effect of different Reynolds numbers in the range of 5000 < Re < 25000 on heat transfer characteristics of nanofluids flowing through the channel is investigated. The numerical results indicate that SiO2-water has the highest Nusselt number compared to other nanofluids while it has the lowest heat transfer coefficient due to low thermal conductivity. The Nusselt number increases with the increase of the Reynolds number and the volume fraction of nanoparticles. The results of simulation show a good agreement with the existing experimental correlations.

  12. Transformation formulas relating geodetic coordinates to a tangent to Earth, plane coordinate system

    NASA Technical Reports Server (NTRS)

    Credeur, L.

    1981-01-01

    Formulas and their approximation were developed to map geodetic position to an Earth tangent plane with an airport centered rectangular coordinate system. The transformations were developed for use in a terminal area air traffic model with deterministic aircraft traffic. The exact configured vehicle's approximation equations used in their precision microwave landing system navigation experiments.

  13. Effect of the angle of attack of a rectangular wing on the heat transfer enhancement in channel flow at low Reynolds number

    NASA Astrophysics Data System (ADS)

    Khanjian, Assadour; Habchi, Charbel; Russeil, Serge; Bougeard, Daniel; Lemenand, Thierry

    2018-05-01

    Convective heat transfer enhancement can be achieved by generating secondary flow structures that are added to the main flow to intensify the fluid exchange between hot and cold regions. One method involves the use of vortex generators to produce streamwise and transverse vortices superimposed to the main flow. This study presents numerical computation results of laminar convection heat transfer in a rectangular channel whose bottom wall is equipped with one row of rectangular wing vortex generators. The governing equations are solved using finite volume method by considering steady state, laminar regime and incompressible flow. Three-dimensional numerical simulations are performed to study the effect of the angle of attack α of the wing on heat transfer and pressure drop. Different values are taken into consideration within the range 0° < α < 30 °. For all of these geometrical configurations the Reynolds number is maintained to Re = 456 . To assess the effect of the angle of attack on the heat transfer enhancement, Nusselt number and the friction factor are studied on both local and global perspectives. Also, the location of the generated vortices within the channel is studied, as well as their effect on the heat transfer enhancement throughout the channel for all α values . Based on both local and global analysis, our results show that the angle of attack α has a direct impact on the heat transfer enhancement. By increasing its value, it leads to better enhancement until an optimal value is reached, beyond which the thermal performances decrease.

  14. Boiling Visualization and Critical Heat Flux Phenomena In Narrow Rectangular Gap

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

    J. J. Kim; Y. H. Kim; S. J. Kim

    2004-12-01

    An experimental study was performed to investifate the pool boling critical hear flux (CHF) on one-dimensional inclined rectangular channels with narrow gaps by changing the orientation of a copper test heater assembly. In a pool of saturated water at atmospheric pressure, the test parameters include the gap sizes of 1,2,5, and 10 mm, andthe surface orientation angles from the downward facing position (180 degrees) to the vertical position (90 degress) respectively.

  15. Experimental investigation of the two-phase flow regimes and pressure drop in horizontal mini-size rectangular test section

    NASA Astrophysics Data System (ADS)

    Elazhary, Amr Mohamed; Soliman, Hassan M.

    2012-10-01

    An experimental study was conducted in order to investigate two-phase flow regimes and fully developed pressure drop in a mini-size, horizontal rectangular channel. The test section was machined in the form of an impacting tee junction in an acrylic block (in order to facilitate visualization) with a rectangular cross-section of 1.87-mm height on 20-mm width on the inlet and outlet sides. Pressure drop measurement and flow regime identification were performed on all three sides of the junction. Air-water mixtures at 200 kPa (abs) and room temperature were used as the test fluids. Four flow regimes were identified visually: bubbly, plug, churn, and annular over the ranges of gas and liquid superficial velocities of 0.04 ≤ JG ≤ 10 m/s and 0.02 ≤ JL ≤ 0.7 m/s, respectively, and a flow regime map was developed. Accuracy of the pressure-measurement technique was validated with single-phase, laminar and turbulent, fully developed data. Two-phase experiments were conducted for eight different inlet conditions and various mass splits at the junction. Comparisons were conducted between the present data and former correlations for the fully developed two-phase pressure drop in rectangular channels with similar sizes. Wide deviations were found among these correlations, and the correlations that agreed best with the present data were identified.

  16. Inertial migrations of cylindrical particles in rectangular microchannels: Variations of equilibrium positions and equivalent diameters

    NASA Astrophysics Data System (ADS)

    Su, Jinghong; Chen, Xiaodong; Hu, Guoqing

    2018-03-01

    Inertial migration has emerged as an efficient tool for manipulating both biological and engineered particles that commonly exist with non-spherical shapes in microfluidic devices. There have been numerous studies on the inertial migration of spherical particles, whereas the non-spherical particles are still largely unexplored. Here, we conduct three-dimensional direct numerical simulations to study the inertial migration of rigid cylindrical particles in rectangular microchannels with different width/height ratios under the channel Reynolds numbers (Re) varying from 50 to 400. Cylindrical particles with different length/diameter ratios and blockage ratios are also concerned. Distributions of surface force with the change of rotation angle show that surface stresses acting on the particle end near the wall are the major contributors to the particle rotation. We obtain lift forces experienced by cylindrical particles at different lateral positions on cross sections of two types of microchannels at various Re. It is found that there are always four stable equilibrium positions on the cross section of a square channel, while the stable positions are two or four in a rectangular channel, depending on Re. By comparing the equilibrium positions of cylindrical particles and spherical particles, we demonstrate that the equivalent diameter of cylindrical particles monotonously increases with Re. Our work indicates the influence of a non-spherical shape on the inertial migration and can be useful for the precise manipulation of non-spherical particles.

  17. 33 CFR 148.215 - What if a port has plans for a deep draft channel and harbor?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... General § 148.215 What if a port has plans for a deep draft channel and harbor? (a) If a State port will be directly connected by pipeline to a proposed deepwater port, and has existing plans for a deep... deep draft channel and harbor? 148.215 Section 148.215 Navigation and Navigable Waters COAST GUARD...

  18. Inertial focusing of spherical particles in rectangular microchannels over a wide range of Reynolds numbers.

    PubMed

    Liu, Chao; Hu, Guoqing; Jiang, Xingyu; Sun, Jiashu

    2015-02-21

    Inertial microfluidics has emerged as an important tool for manipulating particles and cells. For a better design of inertial microfluidic devices, we conduct 3D direct numerical simulations (DNS) and experiments to determine the complicated dependence of focusing behaviour on the particle size, channel aspect ratio, and channel Reynolds number. We find that the well-known focusing of the particles at the two centers of the long channel walls occurs at a relatively low Reynolds number, whereas additional stable equilibrium positions emerge close to the short walls with increasing Reynolds number. Based on the numerically calculated trajectories of particles, we propose a two-stage particle migration which is consistent with experimental observations. We further present a general criterion to secure good focusing of particles for high flow rates. This work thus provides physical insight into the multiplex focusing of particles in rectangular microchannels with different geometries and Reynolds numbers, and paves the way for efficiently designing inertial microfluidic devices.

  19. Aspect Ratio Model for Radiation-Tolerant Dummy Gate-Assisted n-MOSFET Layout.

    PubMed

    Lee, Min Su; Lee, Hee Chul

    2014-01-01

    In order to acquire radiation-tolerant characteristics in integrated circuits, a dummy gate-assisted n-type metal oxide semiconductor field effect transistor (DGA n-MOSFET) layout was adopted. The DGA n-MOSFET has a different channel shape compared with the standard n-MOSFET. The standard n-MOSFET has a rectangular channel shape, whereas the DGA n-MOSFET has an extended rectangular shape at the edge of the source and drain, which affects its aspect ratio. In order to increase its practical use, a new aspect ratio model is proposed for the DGA n-MOSFET and this model is evaluated through three-dimensional simulations and measurements of the fabricated devices. The proposed aspect ratio model for the DGA n-MOSFET exhibits good agreement with the simulation and measurement results.

  20. Aspect Ratio Model for Radiation-Tolerant Dummy Gate-Assisted n-MOSFET Layout

    PubMed Central

    Lee, Min Su; Lee, Hee Chul

    2014-01-01

    In order to acquire radiation-tolerant characteristics in integrated circuits, a dummy gate-assisted n-type metal oxide semiconductor field effect transistor (DGA n-MOSFET) layout was adopted. The DGA n-MOSFET has a different channel shape compared with the standard n-MOSFET. The standard n-MOSFET has a rectangular channel shape, whereas the DGA n-MOSFET has an extended rectangular shape at the edge of the source and drain, which affects its aspect ratio. In order to increase its practical use, a new aspect ratio model is proposed for the DGA n-MOSFET and this model is evaluated through three-dimensional simulations and measurements of the fabricated devices. The proposed aspect ratio model for the DGA n-MOSFET exhibits good agreement with the simulation and measurement results. PMID:27350975

  1. Houston-Galveston Navigation Channels, Texas Project. Navigation Channel Sedimentation Study, Phase 2

    DTIC Science & Technology

    2008-07-01

    volume of the system is 64 L. The propeller pump is 2.6 m upstream from the bed sediment sample tray . Flows in the VOST are up to 1.54 m/s, generating...159 High Flow Water Year...160 Low Flow Water Year

  2. The Atlantic Coast of Maryland, Sediment Budget Update: Tier 2, Assateague Island and Ocean City Inlet

    DTIC Science & Technology

    2016-06-01

    manual bypassing of sediment from the ebb/flood shoal to Assateague Island, and periodic maintenance of the Federally authorized navigation channels ...Assateague Island into the channel . A greater understanding of these fluxes could be gained through modeling the hydrodynamics and sediment pathways...Federally authorized navigation channels . This would require data collection necessary to quantify the overwash influence on the sediment budget

  3. 75 FR 47713 - Regulated Navigation Area; Galveston Channel, TX

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-09

    .... SUMMARY: The Coast Guard is establishing a regulated navigation area (RNA) across the entire width of the Galveston Channel in the vicinity of Sector Field Office (SFO) Galveston, Texas. This RNA will require... Port Houston-Galveston or a designated representative. This RNA is needed to protect the Coast Guard...

  4. 33 CFR 118.110 - Daymarks and lateral lighting on bridges.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... through bridges with U.S. aids to navigation system lateral marks and lights installed on the... flashing, flashing, isophase or occulting red and green lights to mark the main channels. (b) If lateral system lights are required or authorized to mark the main navigation channels, fixed yellow lights shall...

  5. 33 CFR 118.110 - Daymarks and lateral lighting on bridges.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... through bridges with U.S. aids to navigation system lateral marks and lights installed on the... flashing, flashing, isophase or occulting red and green lights to mark the main channels. (b) If lateral system lights are required or authorized to mark the main navigation channels, fixed yellow lights shall...

  6. 33 CFR 118.110 - Daymarks and lateral lighting on bridges.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... through bridges with U.S. aids to navigation system lateral marks and lights installed on the... flashing, flashing, isophase or occulting red and green lights to mark the main channels. (b) If lateral system lights are required or authorized to mark the main navigation channels, fixed yellow lights shall...

  7. Enhanced Small Scale Heat Transfer in Rectangular Channels using Autonomous, Aero-Elastically Fluttering Reeds

    NASA Astrophysics Data System (ADS)

    Jha, Sourabh; Crittenden, Thomas; Glezer, Ari

    2017-11-01

    The limits of low Reynolds number forced convection heat transport within rectangular, mm-scale channels that model segments of air-cooled heat sinks are overcome by the deliberate formation of unsteady small-scale vortical motions that are induced by autonomous aero-elastic fluttering of cantilevered planar thin-film reeds. The coupled flow-structure interactions between the fluttering reeds and the embedding channel flow and the formation and evolution of the induced unsteady small-scale vortical motions are explored using video imaging and PIV. Concave/convex undulations of the reed's surface that are bounded by the channel's walls lead to the formation and advection of cells of vorticity concentration and ultimately to alternate shedding of spanwise CW and CCW vortices. These vortices scale with the channel height, and result in increased turbulent kinetic energy and enhanced dissipation that persist far downstream from the reed and are reminiscent of a turbulent flow at significantly higher Reynolds numbers (e.g., at Re = 800, TKE increases by 86% ,40 channel widths downstream of reed tip). These small-scale motions lead to strong enhancement in heat transfer that increases with Re (e.g., at Re = 1,000 and 14,000, Nu increases by 36% and 91%, respectively). The utility of this approach is demonstrated in improving the thermal performance of low-Re heat sinks in air-cooled condensers of thermoelectric power plants. NSF-EPRI.

  8. Characterization of the startup transient electrokinetic flow in rectangular channels of arbitrary dimensions, zeta potential distribution, and time-varying pressure gradient.

    PubMed

    Miller, Andrew; Villegas, Arturo; Diez, F Javier

    2015-03-01

    The solution to the startup transient EOF in an arbitrary rectangular microchannel is derived analytically and validated experimentally. This full 2D transient solution describes the evolution of the flow through five distinct periods until reaching a final steady state. The derived analytical velocity solution is validated experimentally for different channel sizes and aspect ratios under time-varying pressure gradients. The experiments used a time resolved micro particle image velocimetry technique to calculate the startup transient velocity profiles. The measurements captured the effect of time-varying pressure gradient fields derived in the analytical solutions. This is tested by using small reservoirs at both ends of the channel which allowed a time-varying pressure gradient to develop with a time scale on the order of the transient EOF. Results showed that under these common conditions, the effect of the pressure build up in the reservoirs on the temporal development of the transient startup EOF in the channels cannot be neglected. The measurements also captured the analytical predictions for channel walls made of different materials (i.e., zeta potentials). This was tested in channels that had three PDMS and one quartz wall, resulting in a flow with an asymmetric velocity profile due to variations in the zeta potential between the walls. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Effect of dynamic load on water flow boiling CHF in rectangular channels

    NASA Astrophysics Data System (ADS)

    Zhang, Zhao; Song, Baoyin; Li, Gang; Cao, Xi

    2018-06-01

    Experimental investigation into flow boiling critical heat flux (CHF) characteristics in narrow rectangular channels was performed under rotating state using distilled water as working fluids. The effects of mass velocity, inlet temperature and heating orientation on CHF under dynamic load were analyzed and discussed in this paper. The results show that the dynamic load obviously influences the CHF through enhancing two-phase mixing up and bubble separating. The greater the dynamic load, the higher the CHF values. The CHF values increase with the increase of mass velocity and inlet subcooling in the experimental range. The magnitude of CHF increase with the dynamic load for bottom heating is greater than that for up heating. The present study and its newly correlation may provide some technical supports in designing the airborne vapor cycle system.

  10. 33 CFR 110.197 - Galveston Harbor, Bolivar Roads Channel, Texas.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Galveston Harbor, Bolivar Roads... Roads Channel, Texas. (a)(1) Anchorage area (A). The water bounded by a line connecting the following... the hull or rigging of any anchored vessel shall extend outside the limits of the anchorage area. (7...

  11. 33 CFR 110.197 - Galveston Harbor, Bolivar Roads Channel, Texas.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Galveston Harbor, Bolivar Roads... Roads Channel, Texas. (a)(1) Anchorage area (A). The water bounded by a line connecting the following... the hull or rigging of any anchored vessel shall extend outside the limits of the anchorage area. (7...

  12. 33 CFR 165.805 - Security Zones; Calcasieu River and Ship Channel, Louisiana.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Security Zones; Calcasieu River... § 165.805 Security Zones; Calcasieu River and Ship Channel, Louisiana. (a) Location. (1) The following areas are designated as fixed security zones (all coordinates are based upon North American Datum of...

  13. 33 CFR 165.805 - Security Zones; Calcasieu River and Ship Channel, Louisiana.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Security Zones; Calcasieu River... § 165.805 Security Zones; Calcasieu River and Ship Channel, Louisiana. (a) Location. (1) The following areas are designated as fixed security zones (all coordinates are based upon North American Datum of...

  14. 33 CFR 165.805 - Security Zones; Calcasieu River and Ship Channel, Louisiana.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Security Zones; Calcasieu River... § 165.805 Security Zones; Calcasieu River and Ship Channel, Louisiana. (a) Location. (1) The following areas are designated as fixed security zones (all coordinates are based upon North American Datum of...

  15. 33 CFR 165.805 - Security Zones; Calcasieu River and Ship Channel, Louisiana.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Security Zones; Calcasieu River... § 165.805 Security Zones; Calcasieu River and Ship Channel, Louisiana. (a) Location. (1) The following areas are designated as fixed security zones (all coordinates are based upon North American Datum of...

  16. 33 CFR 239.5 - Engineering considerations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Engineering considerations. 239.5 Section 239.5 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF... § 239.5 Engineering considerations. Reports on proposals to provide covered channels shall include a...

  17. 33 CFR 239.5 - Engineering considerations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Engineering considerations. 239.5 Section 239.5 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF... § 239.5 Engineering considerations. Reports on proposals to provide covered channels shall include a...

  18. 33 CFR 239.5 - Engineering considerations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Engineering considerations. 239.5 Section 239.5 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF... § 239.5 Engineering considerations. Reports on proposals to provide covered channels shall include a...

  19. 33 CFR 239.5 - Engineering considerations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Engineering considerations. 239.5 Section 239.5 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF... § 239.5 Engineering considerations. Reports on proposals to provide covered channels shall include a...

  20. 33 CFR 239.5 - Engineering considerations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Engineering considerations. 239.5 Section 239.5 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF... § 239.5 Engineering considerations. Reports on proposals to provide covered channels shall include a...

  1. Space Vehicle Guidance, Navigation, Control, and Estimation Operations Technologies

    DTIC Science & Technology

    2018-03-29

    angular position around the ellipse, and the out-of-place amplitude and angular position. These elements are explicitly relatable to the six rectangular...quasi) second order relative orbital elements are explored. One theory uses the expanded solution form and introduces several instantaneous ellipses...In each case, the theory quantifies distortion of the first order relative orbital elements when including second order effects. The new variables are

  2. 33 CFR 334.170 - Chesapeake Bay, in the vicinity of Chesapeake Beach, Md.; firing range, Naval Research Laboratory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... of Chesapeake Beach, Md.; firing range, Naval Research Laboratory. 334.170 Section 334.170 Navigation..., Naval Research Laboratory. (a) The danger zone—(1) Area A. A roughly rectangular area bounded on the... enter or remain in Area B or Area C between the hours of 1:00 p.m. and 5:00 p.m. daily except Sundays...

  3. 33 CFR 334.170 - Chesapeake Bay, in the vicinity of Chesapeake Beach, Md.; firing range, Naval Research Laboratory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... of Chesapeake Beach, Md.; firing range, Naval Research Laboratory. 334.170 Section 334.170 Navigation..., Naval Research Laboratory. (a) The danger zone—(1) Area A. A roughly rectangular area bounded on the... enter or remain in Area B or Area C between the hours of 1:00 p.m. and 5:00 p.m. daily except Sundays...

  4. 33 CFR 67.15-10 - Spoil banks, artificial islands, and dredged channels.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Spoil banks, artificial islands..., DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION AIDS TO NAVIGATION ON ARTIFICIAL ISLANDS AND FIXED STRUCTURES Miscellaneous Marking Requirements § 67.15-10 Spoil banks, artificial islands, and dredged...

  5. 33 CFR 67.15-10 - Spoil banks, artificial islands, and dredged channels.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Spoil banks, artificial islands..., DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION AIDS TO NAVIGATION ON ARTIFICIAL ISLANDS AND FIXED STRUCTURES Miscellaneous Marking Requirements § 67.15-10 Spoil banks, artificial islands, and dredged...

  6. 33 CFR 110.84 - Black Rock Channel opposite foot of Porter Avenue, Buffalo, N.Y.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... of Porter Avenue, Buffalo, N.Y. 110.84 Section 110.84 Navigation and Navigable Waters COAST GUARD... Channel opposite foot of Porter Avenue, Buffalo, N.Y. An area extending northwesterly between Black Rock... Triangulation Marker “N-5” on Bird Island Pier; thence southeasterly along the pier a distance of approximately...

  7. Space shuttle orbit maneuvering engine reusable thrust chamber. Task 13: Subscale helium ingestion and two dimensional heating test report

    NASA Technical Reports Server (NTRS)

    Tobin, R. D.

    1974-01-01

    Descriptions are given of the test hardware, facility, procedures, and results of electrically heated tube, channel and panel tests conducted to determine effects of helium ingestion, two dimensional conduction, and plugged coolant channels on operating limits of convectively cooled chambers typical of space shuttle orbit maneuvering engine designs. Helium ingestion in froth form, was studied in tubular and rectangular single channel test sections. Plugged channel simulation was investigated in a three channel panel. Burn-out limits (transition of film boiling) were studied in both single channel and panel test sections to determine 2-D conduction effects as compared to tubular test results.

  8. Dean Flow Dynamics in Low-Aspect Ratio Spiral Microchannels

    PubMed Central

    Nivedita, Nivedita; Ligrani, Phillip; Papautsky, Ian

    2017-01-01

    A wide range of microfluidic cell-sorting devices has emerged in recent years, based on both passive and active methods of separation. Curvilinear channel geometries are often used in these systems due to presence of secondary flows, which can provide high throughput and sorting efficiency. Most of these devices are designed on the assumption of two counter rotating Dean vortices present in the curved rectangular channels and existing in the state of steady rotation and amplitude. In this work, we investigate these secondary flows in low aspect ratio spiral rectangular microchannels and define their development with respect to the channel aspect ratio and Dean number. This work is the first to experimentally and numerically investigate Dean flows in microchannels for Re > 100, and show presence of secondary Dean vortices beyond a critical Dean number. We further demonstrate the impact of these multiple vortices on particle and cell focusing. Ultimately, this work offers new insights into secondary flow instabilities for low-aspect ratio, spiral microchannels, with improved flow models for design of more precise and efficient microfluidic devices for applications such as cell sorting and micromixing. PMID:28281579

  9. Fabrication of unique 3D microparticles in non-rectangular microchannels with flow lithography

    NASA Astrophysics Data System (ADS)

    Nam, Sung Min; Kim, Kibeom; Park, Wook; Lee, Wonhee

    Invention of flow lithography has offered a simple yet effective method of fabricating micro-particles. However particles produced with conventional techniques were largely limited to 2-dimensional shapes projected to form a column. We proposed inexpensive and simple soft-lithography techniques to fabricate micro-channels with various cross-sectional shapes. The non-rectangular channels are then used to fabricate micro-particles using flow lithography resulting in interesting 3D shapes such as tetrahedrals or half-pyramids. In addition, a microfluidic device capable of fabricating multi-layered micro-particles was developed. On-chip PDMS valves are used to trap and position the particle at the precise location in microchannel with varying cross-section. Multilayer particles are generated by sequential monomer exchange and polymerization along the channel. While conventional multi-layered particles made with droplet generators require their layer materials be dissolved in immiscible fluids, the new method allows diverse choice of materials, not limited to their diffusibility. The multilayer 3D particles can be applied in areas such as drug delivery and tissue engineering.

  10. 33 CFR 165.1110 - Security Zone: Coronado Bay Bridge, San Diego, CA.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Bridge, San Diego, CA. 165.1110 Section 165.1110 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... § 165.1110 Security Zone: Coronado Bay Bridge, San Diego, CA. (a) Location. All navigable waters of San... pilings of the Coronado Bay Bridge. These security zones will not restrict the main navigational channel...

  11. 33 CFR 165.1110 - Security Zone: Coronado Bay Bridge, San Diego, CA.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Bridge, San Diego, CA. 165.1110 Section 165.1110 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... § 165.1110 Security Zone: Coronado Bay Bridge, San Diego, CA. (a) Location. All navigable waters of San... pilings of the Coronado Bay Bridge. These security zones will not restrict the main navigational channel...

  12. Three-dimensional numerical simulations of turbulent cavitating flow in a rectangular channel

    NASA Astrophysics Data System (ADS)

    Iben, Uwe; Makhnov, Andrei; Schmidt, Alexander

    2018-05-01

    Cavitation is a phenomenon of formation of bubbles (cavities) in liquid as a result of pressure drop. Cavitation plays an important role in a wide range of applications. For example, cavitation is one of the key problems of design and manufacturing of pumps, hydraulic turbines, ship's propellers, etc. Special attention is paid to cavitation erosion and to performance degradation of hydraulic devices (noise, fluctuations of the mass flow rate, etc.) caused by the formation of a two-phase system with an increased compressibility. Therefore, development of a model to predict cavitation inception and collapse of cavities in high-speed turbulent flows is an important fundamental and applied task. To test the algorithm three-dimensional simulations of turbulent flow of a cavitating liquid in a rectangular channel have been conducted. The obtained results demonstrate the efficiency and robustness of the formulated model and the algorithm.

  13. Hydrostatic and Flow Measurements on Wrinkled Membrane Walls

    NASA Astrophysics Data System (ADS)

    Ozsun, Ozgur; Ekinci, Kamil

    2013-03-01

    In this study, we investigate structural properties of wrinkled silicon nitride (SiN) membranes, under both hydrostatic perturbations and flow conditions, through surface profile measurements. Rectangular SiN membranes with linear dimensions of 15 mm × 1 . 5 mm × 1 μ m are fabricated on a 500 - μ m-thick silicon substrate using standard lithography techniques. These thin, initially flat, tension-dominated membranes are wrinkled by bending the silicon substrate. The wrinkled membranes are subsequently incorporated as walls into rectangular micro-channels, which allow both hydrostatic and flow measurements. The structural response of the wrinkles to hydrostatic pressure provides a measure of the various energy scales in the problem. Flow experiments show that the elastic properties and the structural undulations on a compliant membrane completely dominate the flow, possibly providing drag reduction. These measurements pave the way for building and using compliant walls for drag reduction in micro-channels.

  14. Maintenance Operations of the Federal Navigation Channels and Structures at Bolles Harbor, Michigan.

    DTIC Science & Technology

    1978-02-01

    uncontaminated portion of the navigation channel would be placed at the 2600’ x 2600’ open water disposal site located in Lake Erie, approximately 4 1/4...4.38 Commercial Fishing ........................ 25 4.39 Archaeological and Historical Sites ....... 25 4.40 Threatened or Endangered Species...53 ATTACHMENTS Bolles Harbor, Michigan, Project ap ............... *....... 55 Proposed Disposal Sites

  15. Structural Methods to Reduce Navigation Channel Shoaling

    DTIC Science & Technology

    2005-09-01

    to reduce shoaling in navigation channels,” Technical Note, Coastal and Hydraulics Laboratory, U.S. Army Engineer Research and Development Center...deal of interest in reducing or minimizing the quantity of dredging. Considerable research and extensive field experience have offered several methods...project. • Less frequent dredging usually reduces overall dredging costs. • The trap can be intentionally located close to dredged material disposal

  16. Coastal Inlets Research Program

    DTIC Science & Technology

    2015-10-30

    transport, and vessel-induced flow and wake. In FY 2014, the Corps spent approximately $808 million in maintenance dredging of 152 million cubic...yards from Federal navigation channels*. Dredging costs are likely to increase in the future because of increasing fuel, mobilization, and...channels and jetties can have a profound effect on the integrity of the navigation structures, adjacent beaches, estuaries, ecosystems and regions

  17. Frequency-dependent laminar electroosmotic flow in a closed-end rectangular microchannel.

    PubMed

    Marcos; Yang, C; Ooi, K T; Wong, T N; Masliyah, J H

    2004-07-15

    This article presents an analysis of the frequency- and time-dependent electroosmotic flow in a closed-end rectangular microchannel. An exact solution to the modified Navier-Stokes equation governing the ac electroosmotic flow field is obtained by using the Green's function formulation in combination with a complex variable approach. An analytical expression for the induced backpressure gradient is derived. With the Debye-Hückel approximation, the electrical double-layer potential distribution in the channel is obtained by analytically solving the linearized two-dimensional Poisson-Boltzmann equation. Since the counterparts of the flow rate and the electrical current are shown to be linearly proportional to the applied electric field and the pressure gradient, Onsager's principle of reciprocity is demonstrated for transient and ac electroosmotic flows. The time evolution of the electroosmotic flow and the effect of a frequency-dependent ac electric field on the oscillating electroosmotic flow in a closed-end rectangular microchannel are examined. Specifically, the induced pressure gradient is analyzed under effects of the channel dimension and the frequency of electric field. In addition, based on the Stokes second problem, the solution of the slip velocity approximation is presented for comparison with the results obtained from the analytical scheme developed in this study. Copyright 2004 Elsevier Inc.

  18. 33 CFR 162.245 - Kenai River, Kenai, Alaska; use, administration, and navigation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Kenai River, Kenai, Alaska; use... § 162.245 Kenai River, Kenai, Alaska; use, administration, and navigation. (a) The area. The main channel area of the river, having a width of 150 feet, beginning at a point directly offshore from the...

  19. 33 CFR 118.65 - Lights on fixed bridges.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Lights on fixed bridges. 118.65... LIGHTING AND OTHER SIGNALS § 118.65 Lights on fixed bridges. (a) Each fixed bridge span over a navigable... range of two green lights, and each margin of each navigable channel will be marked by a red light...

  20. 33 CFR 118.65 - Lights on fixed bridges.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Lights on fixed bridges. 118.65... LIGHTING AND OTHER SIGNALS § 118.65 Lights on fixed bridges. (a) Each fixed bridge span over a navigable... range of two green lights, and each margin of each navigable channel will be marked by a red light...

  1. 33 CFR 118.65 - Lights on fixed bridges.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Lights on fixed bridges. 118.65... LIGHTING AND OTHER SIGNALS § 118.65 Lights on fixed bridges. (a) Each fixed bridge span over a navigable... range of two green lights, and each margin of each navigable channel will be marked by a red light...

  2. 33 CFR 118.65 - Lights on fixed bridges.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Lights on fixed bridges. 118.65... LIGHTING AND OTHER SIGNALS § 118.65 Lights on fixed bridges. (a) Each fixed bridge span over a navigable... range of two green lights, and each margin of each navigable channel will be marked by a red light...

  3. Traffic of leukocytes in microfluidic channels with rectangular and rounded cross-sections.

    PubMed

    Yang, Xiaoxi; Forouzan, Omid; Burns, Jennie M; Shevkoplyas, Sergey S

    2011-10-07

    Traffic of leukocytes in microvascular networks (particularly through arteriolar bifurcations and venular convergences) affects the dynamics of capillary blood flow, initiation of leukocyte adhesion during inflammation, and localization and development of atherosclerotic plaques in vivo. Recently, a growing research effort has been focused on fabricating microvascular networks comprising artificial vessels with more realistic, rounded cross-sections. This paper investigated the impact of the cross-sectional geometry of microchannels on the traffic of leukocytes flowing with human whole blood through a non-symmetrical bifurcation that consisted of a 50 μm mother channel bifurcating into 30 μm and 50 μm daughter branches. Two versions of the same bifurcation comprising microchannels with rectangular and rounded cross-sections were fabricated using conventional multi-layer photolithography to produce rectangular microchannles that were then rounded in situ using a recently developed method of liquid PDMS/air bubble injection. For microchannels with rounded cross-sections, about two-thirds of marginated leukocytes traveling along a path in the top plane of the bifurcation entered the smallest 30 μm daughter branch. This distribution was reversed in microchannels with rectangular cross-sections--the majority of leukocytes traveling along a similar path continued to follow the 50 μm microchannels after the bifurcation. This dramatic difference in the distribution of leukocyte traffic among the branches of the bifurcation can be explained by preferential margination of leukocytes towards the corners of the 50 μm mother microchannels with rectangular cross-sections, and by the additional hindrance to leukocyte entry created by the sharp transition from the 50 μm mother microchannel to the 30 μm daughter branch at the intersection. The results of this study suggest that the trajectories of marginated leukocytes passing through non-symmetrical bifurcations are significantly affected by the cross-sectional geometry of microchannels and emphasize the importance of using microfludic systems with geometrical configurations closely matching physiological configurations when modeling the dynamics of whole blood flow in the microcirculation.

  4. 33 CFR 162.255 - Wrangell Narrows, Alaska; use, administration, and navigation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Channel Buoy 1 TC. East of Tow Channel Buoy 3 TC. West of Tow Channel Buoy 4 TC. East of Colorado Reef... Tow Channel Buoy 5 TC. East of Tow Channel Buoy 7 TC. West of Petersburg: East of Wrangell Narrows...

  5. 33 CFR 162.255 - Wrangell Narrows, Alaska; use, administration, and navigation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Channel Buoy 1 TC. East of Tow Channel Buoy 3 TC. West of Tow Channel Buoy 4 TC. East of Colorado Reef... Tow Channel Buoy 5 TC. East of Tow Channel Buoy 7 TC. West of Petersburg: East of Wrangell Narrows...

  6. 47 CFR 15.123 - Labeling of digital cable ready products.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) Allows navigation of channels based on channel information (virtual channel map and source names... independent laboratory with personnel knowledgeable with respect to the standards referenced in paragraph (b...

  7. Determination of the functioning parameters in asymmetrical flow field-flow fractionation with an exponential channel.

    PubMed

    Déjardin, P

    2013-08-30

    The flow conditions in normal mode asymmetric flow field-flow fractionation are determined to approach the high retention limit with the requirement d≪l≪w, where d is the particle diameter, l the characteristic length of the sample exponential distribution and w the channel height. The optimal entrance velocity is determined from the solute characteristics, the channel geometry (exponential to rectangular) and the membrane properties, according to a model providing the velocity fields all over the cell length. In addition, a method is proposed for in situ determination of the channel height. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Specifics of heat and mass transfer in spherical dimples under the effect of external factors

    NASA Astrophysics Data System (ADS)

    Shchukin, A. V.; Il'inkov, A. V.; Takmovtsev, V. V.; Khabibullin, I. I.

    2017-06-01

    The specifics are examined of heat transfer enhancement with spherical dimples under the effect of factors important for practice and characteristic of cooling systems of gas-turbine engines and power units. This experimental investigation deals with the effect of the following factors on the flow in a channel with hemispherical dimples: continuous air swirl in an annulus with dimples on its concave wall, dimples on the convex or concave wall of a curved rectangular channel, imposition of regular velocity fluctuations on the external flow in a straight rectangular channel, and adverse or favorable pressure gradient along the flow direction. The flow is turbulent. Reynolds numbers based on the channel hydraulic diameter are on the order of 104. Results of the investigation of a model of a two-cavity diffuser dimple proposed by the authors are presented. It has been found that results for channels with spherical dimples and for smooth channels differ not only quantitatively but also qualitatively. Thus, if the effect of centrifugal mass forces on convex and concave surfaces with hemispherical dimples and in a smooth channel is almost the same (quantitative and qualitative indicators are identical), the pressure gradient in the flow direction brings about the drastically opposite results. At the same time, the quantitative contribution to a change in heat transfer in hemispherical dimples is different and depends on the impact type. The results are discussed with the use of physical models created on the basis of the results of flow visualization studies and data on the turbulence intensity, pressure coefficient, etc. Results of the investigations suggest that application of spherical dimples under nonstandard conditions requires the calculated heat transfer to be corrected to account for one or another effect.

  9. 75 FR 38923 - Regulated Navigation Area: Niantic Railroad Bridge Construction, Niantic, CT

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-07

    ...-AA11 Regulated Navigation Area: Niantic Railroad Bridge Construction, Niantic, CT AGENCY: Coast Guard... Niantic River Channel under and surrounding the Amtrak Railroad Bridge that crosses Niantic Bay in the... on the navigable waters during the construction of the Niantic Railroad Bridge. DATES: This rule is...

  10. Lattice Boltzmann Equation On a 2D Rectangular Grid

    NASA Technical Reports Server (NTRS)

    Bouzidi, MHamed; DHumieres, Dominique; Lallemand, Pierre; Luo, Li-Shi; Bushnell, Dennis M. (Technical Monitor)

    2002-01-01

    We construct a multi-relaxation lattice Boltzmann model on a two-dimensional rectangular grid. The model is partly inspired by a previous work of Koelman to construct a lattice BGK model on a two-dimensional rectangular grid. The linearized dispersion equation is analyzed to obtain the constraints on the isotropy of the transport coefficients and Galilean invariance for various wave propagations in the model. The linear stability of the model is also studied. The model is numerically tested for three cases: (a) a vortex moving with a constant velocity on a mesh periodic boundary conditions; (b) Poiseuille flow with an arbitrasy inclined angle with respect to the lattice orientation: and (c) a cylinder &symmetrically placed in a channel. The numerical results of these tests are compared with either analytic solutions or the results obtained by other methods. Satisfactory results are obtained for the numerical simulations.

  11. Analytical study of mixed electroosmotic-pressure-driven flow in rectangular micro-channels

    NASA Astrophysics Data System (ADS)

    Movahed, Saeid; Kamali, Reza; Eghtesad, Mohammad; Khosravifard, Amir

    2013-09-01

    Operational state of many miniaturized devices deals with flow field in microchannels. Pressure-driven flow (PDF) and electroosmotic flow (EOF) can be recognized as the two most important types of the flow field in such channels. EOF has many advantages in comparison with PDF, such as being vibration free and not requiring any external mechanical pumps or moving parts. However, the disadvantages of this type of flow such as Joule heating, electrophoresis demixing, and not being suitable for mobile devices must be taken into consideration carefully. By using mixed electroosmotic/pressure-driven flow, the role of EOF in producing desired velocity profile will be reduced. In this way, the advantages of EOF can be exploited, and its disadvantages can be prevented. Induced pressure gradient can be utilized in order to control the separation in the system. Furthermore, in many complicated geometries such as T-shape microchannels, turns may induce pressure gradient to the electroosmotic velocity. While analytical formulas are completely essential for analysis and control of any industrial and laboratory microdevices, lack of such formulas in the literature for solving Poisson-Boltzmann equation and predicting electroosmotic velocity field in rectangular domains is evident. In the present study, first a novel method is proposed to solve Poisson-Boltzmann equation (PBE). Subsequently, this solution is utilized to find the electroosmotic and the mixed electroosmotic/pressure-driven velocity profile in a rectangular domain of the microchannels. To demonstrate the accuracy of the presented analytical method in solving PBE and finding electroosmotic velocity, a general nondimensional example is analyzed, and the results are compared with the solution of boundary element method. Additionally, the effects of different nondimensional parameters and also aspect ratio of channels on the electroosmotic part of the flow field will be investigated.

  12. Velocity Vector Field Visualization of Flow in Liquid Acquisition Device Channel

    NASA Technical Reports Server (NTRS)

    McQuillen, John B.; Chao, David F.; Hall, Nancy R.; Zhang, Nengli

    2012-01-01

    A capillary flow liquid acquisition device (LAD) for cryogenic propellants has been developed and tested in NASA Glenn Research Center to meet the requirements of transferring cryogenic liquid propellants from storage tanks to an engine in reduced gravity environments. The prototypical mesh screen channel LAD was fabricated with a mesh screen, covering a rectangular flow channel with a cylindrical outlet tube, and was tested with liquid oxygen (LOX). In order to better understand the performance in various gravity environments and orientations at different liquid submersion depths of the screen channel LAD, a series of computational fluid dynamics (CFD) simulations of LOX flow through the LAD screen channel was undertaken. The resulting velocity vector field visualization for the flow in the channel has been used to reveal the gravity effects on the flow in the screen channel.

  13. Investigation of cellular detonation structure formation via linear stability theory and 2D and 3D numerical simulations

    NASA Astrophysics Data System (ADS)

    Borisov, S. P.; Kudryavtsev, A. N.

    2017-10-01

    Linear and nonlinear stages of the instability of a plane detonation wave (DW) and the subsequent process of formation of cellular detonation structure are investigated. A simple model with one-step irreversible chemical reaction is used. The linear analysis is employed to predict the DW front structure at the early stages of its formation. An emerging eigenvalue problem is solved with a global method using a Chebyshev pseudospectral method and the LAPACK software library. A local iterative shooting procedure is used for eigenvalue refinement. Numerical simulations of a propagation of a DW in plane and rectangular channels are performed with a shock capturing WENO scheme of 5th order. A special method of a computational domain shift is implemented in order to maintain the DW in the domain. It is shown that the linear analysis gives certain predictions about the DW structure that are in agreement with the numerical simulations of early stages of DW propagation. However, at later stages, a merger of detonation cells occurs so that their number is approximately halved. Computations of DW propagation in a square channel reveal two different types of spatial structure of the DW front, "rectangular" and "diagonal" types. A spontaneous transition from the rectangular to diagonal type of structure is observed during propagation of the DW.

  14. Spectral Optical Readout of Rectangular-Miniature Hollow Glass Tubing for Refractive Index Sensing.

    PubMed

    Rigamonti, Giulia; Bello, Valentina; Merlo, Sabina

    2018-02-16

    For answering the growing demand of innovative micro-fluidic devices able to measure the refractive index of samples in extremely low volumes, this paper presents an overview of the performances of a micro-opto-fluidic sensing platform that employs rectangular, miniature hollow glass tubings. The operating principle is described by showing the analytical model of the tubing, obtained as superposition of different optical cavities, and the optical readout method based on spectral reflectivity detection. We have analyzed, in particular, the theoretical and experimental optical features of rectangular tubings with asymmetrical geometry, thus with channel depth larger than the thickness of the glass walls, though all of them in the range of a few tens of micrometers. The origins of the complex line-shape of the spectral response in reflection, due to the different cavities formed by the tubing flat walls and channel, have been investigated using a Fourier transform analysis. The implemented instrumental configuration, based on standard telecom fiberoptic components and a semiconductor broadband optical source emitting in the near infrared wavelength region centered at 1.55 µm, has allowed acquisition of reflectivity spectra for experimental verification of the expected theoretical behavior. We have achieved detection of refractive index variations related to the change of concentration of glucose-water solutions flowing through the tubing by monitoring the spectral shift of the optical resonances.

  15. Advanced porous electrodes with flow channels for vanadium redox flow battery

    NASA Astrophysics Data System (ADS)

    Bhattarai, Arjun; Wai, Nyunt; Schweiss, Ruediger; Whitehead, Adam; Lim, Tuti M.; Hng, Huey Hoon

    2017-02-01

    Improving the overall energy efficiency by reducing pumping power and improving flow distribution of electrolyte, is a major challenge for developers of flow batteries. The use of suitable channels can improve flow distribution through the electrodes and reduce flow resistance, hence reducing the energy consumption of the pumps. Although several studies of vanadium redox flow battery have proposed the use of bipolar plates with flow channels, similar to fuel cell designs, this paper presents the use of flow channels in the porous electrode as an alternative approach. Four types of electrodes with channels: rectangular open channel, interdigitated open cut channel, interdigitated circular poked channel and cross poked circular channels, are studied and compared with a conventional electrode without channels. Our study shows that interdigitated open channels can improve the overall energy efficiency up to 2.7% due to improvement in flow distribution and pump power reduction while interdigitated poked channel can improve up to 2.5% due to improvement in flow distribution.

  16. Brain Oscillatory Activity during Spatial Navigation: Theta and Gamma Activity Link Medial Temporal and Parietal Regions

    ERIC Educational Resources Information Center

    White, David J.; Congedo, Marco; Ciorciari, Joseph; Silberstein, Richard B.

    2012-01-01

    Brain oscillatory correlates of spatial navigation were investigated using blind source separation (BSS) and standardized low resolution electromagnetic tomography (sLORETA) analyses of 62-channel EEG recordings. Twenty-five participants were instructed to navigate to distinct landmark buildings in a previously learned virtual reality town…

  17. Streamline curvature in supersonic shear layers

    NASA Technical Reports Server (NTRS)

    Kibens, V.

    1992-01-01

    Results of an experimental investigation in which a curved shear layer was generated between supersonic flow from a rectangular converging/diverging nozzle and the freestream in a series of open channels with varying radii of curvature are reported. The shear layers exhibit unsteady large-scale activity at supersonic pressure ratios, indicating increased mixing efficiency. This effect contrasts with supersonic flow in a straight channel, for which no large-scale vortical structure development occurs. Curvature must exceed a minimum level before it begins to affect the dynamics of the supersonic shear layer appreciably. The curved channel flows are compared with reference flows consisting of a free jet, a straight channel, and wall jets without sidewalls on a flat and a curved plate.

  18. Analysis of the velocity distribution in different types of ventilation system ducts

    NASA Astrophysics Data System (ADS)

    Peszyński, Kazimierz; Olszewski, Lukasz; Smyk, Emil; Perczyński, Daniel

    2018-06-01

    The paper presents the results obtained during the preliminary studies of circular and rectangular ducts before testing the properties elements (elbows, tees, etc.)of rectangular with rounded corners ducts. The fundamental problem of the studies was to determine the flow rate in the ventilation duct. Due to the size of the channel it was decided to determine the flow rate based on the integration of flow velocity over the considered cross-section. This method requires knowledge of the velocity distribution in the cross section. Approximation of the measured actual profile by the classic and modified Prandtl power-law velocity profile was analysed.

  19. Corner heating in rectangular solid oxide electrochemical cell generators

    DOEpatents

    Reichner, Philip

    1989-01-01

    Disclosed is an improvement in a solid oxide electrochemical cell generator 1 having a rectangular design with four sides that meet at corners, and containing multiplicity of electrically connected fuel cells 11, where a fuel gas is passed over one side of said cells and an oxygen containing gas is passed into said cells, and said fuel is burned to form heat, electricity, and an exhaust gas. The improvement comprises passing the exhaust gases over the multiplicity of cells 11 in such a way that more of the heat in said exhaust gases flows at the corners of the generator, such as through channels 19.

  20. Computation of Turbulent Recirculating Flow in Channels, and for Impingement Cooling

    NASA Technical Reports Server (NTRS)

    Chang, Byong Hoon

    1992-01-01

    Fully elliptic forms of the transport equations have been solved numerically for two flow configurations. The first is turbulent flow in a channel with transverse rectangular ribs, and the second is impingement cooling of a plane surface. Both flows are relevant to proposed designs for active cooling of hypersonic vehicles using supercritical hydrogen as the coolant. Flow downstream of an abrupt pipe expansion and of a backward-facing step were also solved with various near-wall turbulence models as benchmark problems. A simple form of periodicity boundary condition was used for the channel flow with transverse rectangular ribs. The effects of various parameters on heat transfer in channel flow with transverse ribs and in impingement cooling were investigated using the Yap modified Jones and Launder low Reynolds number k-epsilon turbulence model. For the channel flow, predictions were in adequate agreement with experiment for constant property flow, with the results for friction superior to those for heat transfer. For impingement cooling, the agreement with experiment was generally good, but the results suggest that improved modelling of the dissipation rate of turbulence kinetic energy is required in order to obtain improved heat transfer prediction, especially near the stagnation point. The k-epsilon turbulence model was used to predict the mean flow and heat transfer for constant and variable property flows. The effect of variable properties for channel flow was investigated using the same turbulence model, but comparison with experiment yielded no clear conclusions. Also, the wall function method was modified for use in the variable properties flow with a non-adiabatic surface, and an empirical model is suggested to correctly account for the behavior of the viscous sublayer with heating.

  1. Theory of heat transfer and hydraulic resistance of oil radiators

    NASA Technical Reports Server (NTRS)

    Mariamov, N B

    1942-01-01

    In the present report the coefficients of heat transfer and hydraulic resistance are theoretically obtained for the case of laminar flow of a heated viscous liquid in a narrow rectangular channel. The results obtained are applied to the computation of oil radiators, which to a first approximation may be considered as made up of a system of such channels. In conclusion, a comparison is given of the theoretical with the experimental results obtained from tests on airplane oil radiators.

  2. Mercury Thermal Hydraulic Loop (MTHL) Summary Report

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

    Felde, David K.; Crye, Jason Michael; Wendel, Mark W.

    2017-03-01

    The Spallation Neutron Source (SNS) is a high-power linear accelerator built at Oak Ridge National Laboratory (ORNL) which incorporates the use of a flowing liquid mercury target. The Mercury Thermal Hydraulic Loop (MTHL) was constructed to investigate and verify the heat transfer characteristics of liquid mercury in a rectangular channel. This report provides a compilation of previously reported results from the water-cooled and electrically heated straight and curved test sections that simulate the geometry of the window cooling channel in the target nose region.

  3. Space shuttle orbit maneuvering engine reusable thrust chamber: Adverse operating conditions test report

    NASA Technical Reports Server (NTRS)

    Tobin, R. D.

    1974-01-01

    Test hardware, facilities, and procedures are described along with results of electrically heated tube and channel tests conducted to determine adverse operating condition limits for convectively cooled chambers typical of Space Shuttle Orbit Manuevering Engine designs. Hot-start tests were conducted with corrosion resistant steel and nickel tubes with both monomethylhydrazine and 50-50 coolants. Helium ingestion, in both bubble and froth form, was studied in tubular test sections. Helium bubble ingestion and burn-out limits in rectangular channels were also investigated.

  4. Limitations of navigation through Nubaria canal, Egypt.

    PubMed

    Samuel, Magdy G

    2014-03-01

    Alexandria port is the main Egyptian port at the Mediterranean Sea. It is connected to the Nile River through Nubaria canal, which is a main irrigation canal. The canal was designed to irrigate eight hundred thousand acres of agricultural lands, along its course which extends 100 km. The canal has three barrages and four locks to control the flow and allow light navigation by some small barges. Recently, it was decided to improve the locks located on the canal. More than 40 million US$ was invested in these projects. This decision was taken to allow larger barges and increase the transported capacity through the canal. On the other hand, navigation through canals and restricted shallow waterways is affected by several parameters related to both the channel and the vessel. Navigation lane width as well as vessel speed and maneuverability are affected by both the channel and vessel dimensions. Moreover, vessel dimensions and speed will affect the canal stability. In Egypt, there are no guide rules for navigation through narrow and shallow canals such Nubaria. This situation threatens the canal stability and safety of navigation through it. This paper discussed the characteristics of Nubaria canal and the guide rules for navigation in shallow restricted water ways. Dimensions limitation for barges navigating through Nubaria canal is presented. New safe operation rules for navigation in Nubaria canal are also presented. Moreover, the implication of navigation through locks on canal discharge is estimated.

  5. 33 CFR 209.325 - Navigation lights, aids to navigation, navigation charts, and related data policy, practices and...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Engineers will consult with the Coast Guard District Commander during design of channel and harbor...) District Engineers responsible for harbors and waterways shown on charts of the National Ocean Survey (NOAA... Administration, ATTN: National Ocean Survey C-32, Rockville, Md. 20852. Commandant and District Commanders, U.S...

  6. 33 CFR 209.325 - Navigation lights, aids to navigation, navigation charts, and related data policy, practices and...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Engineers will consult with the Coast Guard District Commander during design of channel and harbor...) District Engineers responsible for harbors and waterways shown on charts of the National Ocean Survey (NOAA... Administration, ATTN: National Ocean Survey C-32, Rockville, Md. 20852. Commandant and District Commanders, U.S...

  7. 33 CFR 209.325 - Navigation lights, aids to navigation, navigation charts, and related data policy, practices and...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Engineers will consult with the Coast Guard District Commander during design of channel and harbor...) District Engineers responsible for harbors and waterways shown on charts of the National Ocean Survey (NOAA... Administration, ATTN: National Ocean Survey C-32, Rockville, Md. 20852. Commandant and District Commanders, U.S...

  8. 33 CFR 209.325 - Navigation lights, aids to navigation, navigation charts, and related data policy, practices and...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Engineers will consult with the Coast Guard District Commander during design of channel and harbor...) District Engineers responsible for harbors and waterways shown on charts of the National Ocean Survey (NOAA... Administration, ATTN: National Ocean Survey C-32, Rockville, Md. 20852. Commandant and District Commanders, U.S...

  9. 33 CFR 80.835 - Point Au Fer, LA to Calcasieu Pass, LA.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Point Au Fer, LA to Calcasieu... SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Eighth District § 80.835 Point Au Fer, LA to Calcasieu Pass, LA. (a) A line drawn from Point Au Fer to Atchafalaya Channel Light 34, to Point...

  10. 33 CFR 80.835 - Point Au Fer, LA to Calcasieu Pass, LA.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Point Au Fer, LA to Calcasieu... SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Eighth District § 80.835 Point Au Fer, LA to Calcasieu Pass, LA. (a) A line drawn from Point Au Fer to Atchafalaya Channel Light 34, to Point...

  11. 33 CFR 207.680 - Willamette River, Oreg.; use, administration, and navigation of canal and locks at Willamette...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., administration, and navigation of canal and locks at Willamette Falls, Oreg. 207.680 Section 207.680 Navigation... Willamette Falls, Oreg. (a) Administration—(1) Administrative jurisdiction. The canal and locks and all... VHF-FM radio on channel 14, at WUJ 363, Willamette Falls Locks or by telephone or otherwise notifying...

  12. 33 CFR 207.680 - Willamette River, Oreg.; use, administration, and navigation of canal and locks at Willamette...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., administration, and navigation of canal and locks at Willamette Falls, Oreg. 207.680 Section 207.680 Navigation... Willamette Falls, Oreg. (a) Administration—(1) Administrative jurisdiction. The canal and locks and all... VHF-FM radio on channel 14, at WUJ 363, Willamette Falls Locks or by telephone or otherwise notifying...

  13. 33 CFR 207.680 - Willamette River, Oreg.; use, administration, and navigation of canal and locks at Willamette...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., administration, and navigation of canal and locks at Willamette Falls, Oreg. 207.680 Section 207.680 Navigation... Willamette Falls, Oreg. (a) Administration—(1) Administrative jurisdiction. The canal and locks and all... VHF-FM radio on channel 14, at WUJ 363, Willamette Falls Locks or by telephone or otherwise notifying...

  14. Split-Block Waveguide Polarization Twist for 220 to 325 GHz

    NASA Technical Reports Server (NTRS)

    Ward, John; Chattopadhyay, Goutam

    2008-01-01

    A split-block waveguide circuit that rotates polarization by 90 has been designed with WR-3 input and output waveguides, which are rectangular waveguides used for a nominal frequency range of 220 to 325 GHz. Heretofore, twisted rectangular waveguides equipped with flanges at the input and output have been the standard means of rotating the polarizations of guided microwave signals. However, the fabrication and assembly of such components become difficult at high frequency due to decreasing wavelength, such that twisted rectangular waveguides become impractical at frequencies above a few hundred gigahertz. Conventional twisted rectangular waveguides are also not amenable to integration into highly miniaturized subassemblies of advanced millimeter- and submillimeter-wave detector arrays now undergoing development. In contrast, the present polarization- rotating waveguide can readily be incorporated into complex integrated waveguide circuits such as miniaturized detector arrays fabricated by either conventional end milling of metal blocks or by deep reactive ion etching of silicon blocks. Moreover, the present split-block design can be scaled up in frequency to at least 5 THz. The main step in fabricating a splitblock polarization-rotating waveguide of the present design is to cut channels having special asymmetrically shaped steps into mating upper and lower blocks (see Figure 1). The dimensions of the steps are chosen to be consistent with the WR-3 waveguide cross section, which is 0.864 by 0.432 mm. The channels are characterized by varying widths with constant depths of 0.432, 0.324, and 0.216 mm and by relatively large corner radii to facilitate fabrication. The steps effect both a geometric transition and the corresponding impedance-matched electromagnetic-polarization transition between (1) a WR-3 rectangular waveguide oriented with the electric field vector normal to the block mating surfaces and (2) a corresponding WR-3 waveguide oriented with its electric field vector parallel to the mating surfaces of the blocks. A prototype has been built and tested. Figure 2 presents test results indicative of good performance over nearly the entire WR-3 waveguide frequency band.

  15. 1. CHANNEL DIMENSIONS AND ALIGNMENT RESEARCH INSTRUMENTATION. ENGINEERING TECHNICIAN WITH ...

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

    1. CHANNEL DIMENSIONS AND ALIGNMENT RESEARCH INSTRUMENTATION. ENGINEERING TECHNICIAN WITH VIDEO-CONTROLED MODEL BOAT IN MODEL NAVIGATION CHANNEL. NOTE CONTROL TRAILER IN BACKGROUND. - Waterways Experiment Station, Hydraulics Laboratory, Halls Ferry Road, 2 miles south of I-20, Vicksburg, Warren County, MS

  16. 5. CHANNEL DIMENSIONS AND ALIGNMENT RESEARCH INSTRUMENTATION. VIDEOCONTROLED MODEL BOAT ...

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

    5. CHANNEL DIMENSIONS AND ALIGNMENT RESEARCH INSTRUMENTATION. VIDEO-CONTROLED MODEL BOAT IN MODEL NAVIGATION CHANNEL, HEADING INTO SHELTER AND TOWARD CONTROL TRAILER. - Waterways Experiment Station, Hydraulics Laboratory, Halls Ferry Road, 2 miles south of I-20, Vicksburg, Warren County, MS

  17. 3. CHANNEL DIMENSIONS AND ALIGNMENT RESEARCH INSTRUMENTATION. VIDEOCONTROLED MODEL BOAT ...

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

    3. CHANNEL DIMENSIONS AND ALIGNMENT RESEARCH INSTRUMENTATION. VIDEO-CONTROLED MODEL BOAT IN MODEL NAVIGATION CHANNEL, HEADING AWAY FROM SHELTER AND CONTROL TRAILER. - Waterways Experiment Station, Hydraulics Laboratory, Halls Ferry Road, 2 miles south of I-20, Vicksburg, Warren County, MS

  18. 76 FR 33653 - Maritime Communications

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-09

    ... maritime navigation safety communications system through which marine vessels automatically transmit... may also operate on 12.5 kHz offset frequencies in areas where the licensee is authorized on both... operate on the interstitial channel between Channels 27 and 87 and the interstitial channel between...

  19. 33 CFR 207.460 - Fox River, Wis.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... DEFENSE NAVIGATION REGULATIONS § 207.460 Fox River, Wis. (a) Use, administration and navigation of the... enter a canal or lock whose actual draft exceeds the least depth of water in the channel of the canal as...

  20. 33 CFR 207.460 - Fox River, Wis.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... DEFENSE NAVIGATION REGULATIONS § 207.460 Fox River, Wis. (a) Use, administration and navigation of the... enter a canal or lock whose actual draft exceeds the least depth of water in the channel of the canal as...

  1. Operation of a single-channel, sequential Navstar GPS receiver in a helicopter mission environment

    NASA Technical Reports Server (NTRS)

    Edwards, F. G.; Hamlin, J. R.

    1984-01-01

    It is pointed out that the future utilization of the Navstar Global Positioning System (GPS) by civil helicopters will provide an enhanced performance not obtainable with current navigations systems. GPS will supply properly equipped users with extremely accurate three-dimensional position and velocity information anywhere in the world. Preliminary studies have been conducted to investigate differential GPS concept mechanizations and cost, and to theoretically predict navigation performance and the impact of degradation of the GPS C/A code for national security considerations. The obtained results are encouraging, but certain improvements are needed. As a second step in the program, a single-channel sequential GPS navigator was installed and operated in the NASA SH-3G helicopter. A series of flight tests were conducted. It is found that performance of the Navstar GPS Z-set is quite acceptable to support area navigation and nonprecision approach operations.

  2. Bedform dynamics in a large sand-bedded river using multibeam echo sounding

    NASA Astrophysics Data System (ADS)

    Elliott, C. M.; Jacobson, R. B.; Erwin, S.; Eric, A. B.; DeLonay, A. J.

    2014-12-01

    High-resolution repeat multibeam Echo Sounder (MBES) surveys of the Lower Missouri River in Missouri, USA demonstrate sand bedform movement at a variety of scales over a range of discharges. Understanding dune transport rates and the temporal and spatial variability in sizes across the channel has implications for how sediment transport measurements are made and for understanding the dynamics of habitats utilized by benthic organisms over a range of life stages. Nearly 800 miles of the Lower Missouri River has been altered through channelization and bank stabilization that began in the early 1900's for navigation purposes. Channelization of the Lower Missouri River has created a self-scouring navigation channel with large dunes that migrate downstream over a wide range of discharges. Until the use of MBES surveys on the Missouri River the spatial variability of dune forms in the Missouri River navigation channel was poorly understood. MBES surveys allow for visualization of a range of sand bedforms and repeat measurements demonstrate that dunes are moving over a wide range of discharges on the river. Understanding the spatial variability of dunes and dune movement across the channel and in different channel settings (bends, channel cross-overs, near channel structures) will inform emerging methods in sediment transport measurement that use bedform differencing calculations and provide context for physical bedload sediment sampling on large sand-bedded rivers. Multiple benthic fish species of interest including the endangered pallid sturgeon utilize Missouri River dune fields and adjacent regions for migration, feeding, spawning, early development and dispersal. Surveys using MBES and other hydroacoustic tools provide fisheries biologists with broad new insights into the functionality of bedforms as habitat for critical life stages of large river fish species in the Missouri River, and similar sand-bedded systems.

  3. Microparticle tracking velocimetry as a tool for microfluidic flow measurements

    NASA Astrophysics Data System (ADS)

    Salipante, Paul; Hudson, Steven D.; Schmidt, James W.; Wright, John D.

    2017-07-01

    The accurate measurement of flows in microfluidic channels is important for commercial and research applications. We compare the accuracy of flow measurement techniques over a wide range flows. Flow measurements made using holographic microparticle tracking velocimetry (µPTV) and a gravimetric flow standard over the range of 0.5-100 nL/s agree within 0.25%, well within the uncertainty of the two flow systems. Two commercial thermal flow sensors were used as the intermediaries (transfer standards) between the two flow measurement systems. The gravimetric flow standard was used to calibrate the thermal flow sensors by measuring the rate of change of the mass of liquid in a beaker on a micro-balance as it fills. The holographic µPTV flow measurements were made in a rectangular channel and the flow was seeded with 1 µm diameter polystyrene spheres. The volumetric flow was calculated using the Hagen-Pouiseille solution for a rectangular channel. The uncertainty of both flow measurement systems is given. For the gravimetric standard, relative uncertainty increased for decreasing flows due to surface tension forces between the pipette carrying the flow and the free surface of the liquid in the beaker. The uncertainty of the holographic µPTV measurements did not vary significantly over the measured flow range, and thus comparatively are especially useful at low flow velocities.

  4. Verification of the Hydrodynamic and Sediment Transport Hybrid Modeling System for Cumberland Sound and Kings Bay Navigation Channel, Georgia

    DTIC Science & Technology

    1989-07-01

    TECHNICAL REPORT HL-89-14 VERIFICATION OF THE HYDRODYNAMIC AND Si SEDIMENT TRANSPORT HYBRID MODELING SYSTEM FOR CUMBERLAND SOUND AND I’) KINGS BAY...Hydrodynamic and Sediment Transport Hybrid Modeling System for Cumberland Sound and Kings Bay Navigation Channel, Georgia 12 PERSONAL AUTHOR(S) Granat...Hydrodynamic results from RMA-2V were used in the numerical sediment transport code STUDH in modeling the interaction of the flow transport and

  5. 4. CHANNEL DIMENSIONS AND ALIGNMENT RESEARCH INSTRUMENTATION. VIDEOCONTROLED MODEL BOAT ...

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

    4. CHANNEL DIMENSIONS AND ALIGNMENT RESEARCH INSTRUMENTATION. VIDEO-CONTROLED MODEL BOAT AT FAR END OF MODEL NAVIGATION CHANNEL, HEADING INTO SHELTER AND TOWARD CONTROL TRAILER. - Waterways Experiment Station, Hydraulics Laboratory, Halls Ferry Road, 2 miles south of I-20, Vicksburg, Warren County, MS

  6. 33 CFR 207.275 - McClellan-Kerr Arkansas River navigation system: use, administration, and navigation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    .... Vessels arriving at these markers or the mooring cells immediately upstream and downstream of the lock... mooring facilities at the junction of main stem and secondary channels are to provide temporary mooring...

  7. ETF magnet design alternatives for the national MHD program

    NASA Astrophysics Data System (ADS)

    Marston, P. G.; Thome, R. J.; Dawson, A. M.; Bobrov, E. S.; Hatch, A. M.

    1981-01-01

    Five superconducting magnet designs are evaluated for a 200 MWe test facility requiring a magnet with an on-axis field of 6 T, an inlet bore area of 4 sq m, storing 6 x 10 to the 9th J. The designs include a straightforward rectangular saddle coil set, a 'Cask' configuration based on staves and corner blocks as the main support structure, and an internally cooled, cabled superconductor to minimize the substructure and eliminate the helium vessel. Also, a modular design using six coils with individual helium vessels and an integrated structure produces a simplest configuration which utilizes a natural rectangular interface for packaging the MHD channel and its connections, and results in a lower capital cost.

  8. GPS/GLONASS Time Transfer with 20-Channel Dual GNSS Receiver

    NASA Technical Reports Server (NTRS)

    Daly, P.; Riley, S.

    1996-01-01

    One of the world's two global navigation systems, the Global Positioning System (GPS), is already fully operational (April 1994) and the other, the Global Navigation Satellite System (GLONASS) will become operational by the end of 1995 or early 1996. Each will offer, independently of the other, precise location and time transfer continuously anywhere in the world and indeed in space itself. Many potential users, in particular the civil aviation community, are keenly interested in a joint GPS/GLONASS operation since it would offer substantial advantages in defining and maintaining the integrity of the navigation aid. Results are presented on the characterization of GPS/GLONASS time comparison using a 20-channel dual receiver developed and constructed at the University of Leeds, UK.

  9. Evaluating interception of larval pallid sturgeon on the Lower Missouri River- data acquisition, interpolation, and visualization

    NASA Astrophysics Data System (ADS)

    Bulliner, E. A., IV; Erwin, S. O.; Anderson, B. J.; Wilson, H.; Jacobson, R. B.

    2016-12-01

    The transition from endogenous to exogenous feeding is an important life-stage transition for many riverine fish larvae. On the Missouri River, U.S., riverine alteration has decreased connectivity between the navigation channel and complex, food-producing and foraging areas on the channel margins, namely shallow side channels and sandbar complexes. A favored hypothesis, the interception hypothesis, for recruitment failure of pallid sturgeon is that drifting larvae are not able to exit the highly engineered navigation channel, and therefore starve. We present work exploring measures of hydraulic connectivity between the navigation channel and channel margins using multiple data-collection protocols with acoustic Doppler current profilers (ADCPs). As ADCP datasets alone often do not have high enough spatial resolution to characterize interception and connectivity sufficiently at the scale of drifting sturgeon larvae, they are often supplemented with physical and empirical models. Using boat-mounted ADCPs, we collected 3-dimensional current velocities with a variety of driving techniques (specifically, regularly spaced transects, reciprocal transects, and irregular patterns) around areas of potential larval interception. We then used toolkits based in Python to interpolate 3-dimensional velocity fields at spatial scales finer than the original measurements, and visualized resultant velocity vectors and flowlines in the software package Paraview. Using these visualizations, we investigated the necessary resolution of field measurements required to model connectivity with channel margin areas on large, highly engineered river ecosystems such as the Missouri River. We anticipate that results from this work will be used to help inform models of larval interception under current conditions. Furthermore, results from this work will be useful in developing monitoring strategies to evaluate the restoration of channel complexity to support ecological functions.

  10. 33 CFR 207.640 - Sacramento Deep Water Ship Channel Barge Lock and Approach Canals; use, administration, and...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE NAVIGATION... and the bottom of the lock chamber are −13.0 feet elevation, CofE datum, and usually provides a depth of water ranging from 14.0 feet at LLW to 19.4 feet at HHW, with greater depths during large floods...

  11. The Mystery of Historical Channel Shoaling at Houston-Galveston Navigation Channel, TX

    DTIC Science & Technology

    2011-05-01

    channel traverses through Galveston Inlet, also called Bolivar Roads, which is bordered by Bolivar Island to the north and Galveston Island to the...www.hurricanecity.com/city/galveston.htm. 573 HVJ Associates, Inc. (2003). “Evaluation of Atkinson and Bolivar exhibits.” Turner Collie & Braden, Inc., and

  12. Case Studies of Navigation Channel and Port Sedimentation

    DTIC Science & Technology

    2011-01-14

    Engineering Supplement to Limited Reevaluation Report, Vol. II (1995) 1/14/2011 18 MCNP  Hypotheses Why is channel shoaling more than anticipated? (1...activities have modified shoaling patterns and magnitudes (trawling, dredging and disposal, subsidence/fluid withdrawal). MCNP Hypotheses Why is channel

  13. [Zn(INO) 2(DMF)]·DMF: A new three-dimensional supramolecular open framework containing one-dimensional channels

    NASA Astrophysics Data System (ADS)

    Hong, Jun

    2006-02-01

    A three-dimensional supramolecular compound, [Zn(INO) 2(DMF)]·DMF (1) (INO=isonicotinic acid N-oxide), has been prepared in the DMF solution at room temperature, and characterized by elemental analysis, TG and single crystal X-ray diffraction. The three-dimensional supramolecular open framework of 1 contains rectangular channels with the dimensions of 9.02×10.15 Å, assembled from one-dimensional helical chains via hydrogen-bonding and π-π stacking interactions. Furthermore, compound 1 shows blue photoluminescence at room temperature.

  14. Northeast Florida Regional Sediment Management: Implementation Strategies and Recommendations for Nassau County and Duval County, Florida

    DTIC Science & Technology

    2016-03-01

    51 Figure 21. Mayport beach placement of entrance channel sediment , 1972...................................... 58 Tables Table 1...Entrance Channel dredged sediment placement history by area. ....................... 20 Table 3. Kings Bay Entrance Channel offshore disposal history at...in northeast Florida is beneficial use of sediments dredged from Federal civil works and military navigation channels for shore protection purposes

  15. Brownsville Ship Channel Hydrodynamic Modeling

    DTIC Science & Technology

    2012-01-01

    the Brownsville Ship Channel in Brownsville, Texas. These plans include possible deepening and widening of the ship channel from its connection to...LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR. ERDC/CHL TR-12-6 iii Table of Contents Abstract...Ship Channel, to include potential deepening and widening. In order to assess the impacts of these changes on both navigation and the ecosystem, it is

  16. Multiple estimation channel decoupling and optimization method based on inverse system

    NASA Astrophysics Data System (ADS)

    Wu, Peng; Mu, Rongjun; Zhang, Xin; Deng, Yanpeng

    2018-03-01

    This paper addressed the intelligent autonomous navigation request of intelligent deformation missile, based on the intelligent deformation missile dynamics and kinematics modeling, navigation subsystem solution method and error modeling, and then focuses on the corresponding data fusion and decision fusion technology, decouples the sensitive channel of the filter input through the inverse system of design dynamics to reduce the influence of sudden change of the measurement information on the filter input. Then carrying out a series of simulation experiments, which verified the feasibility of the inverse system decoupling algorithm effectiveness.

  17. Magnetic navigation of an untethered micro device using four stationary coils.

    PubMed

    Ha, Yong H; Choi, Kyung M; Han, Byung H; Cho, Min H; Lee, Soo Y

    2009-01-01

    We introduce a magnetic navigation of a small magnet using four stationary coils. We used a Maxwell gradient coil to get magnetic propulsion force and three Helmholtz coils to control the moving direction of the magnet in the magnetic navigation. Using a three-channel coil driver with output capacity of 320A, we performed magnetic navigation of a small NdFeB magnet with the size of 10 mm x 10 mm x 12 mm on a horizontal plane. When navigated with a slow speed of about 1 mm/s, the magnet kept track of any arbitrary navigational path. We expect the proposed magnetic navigation method can be easily incorporated into the system for human applications since it does not use any moving coils.

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

    Carlson, Thomas J.; Johnson, Gary E.; Woodley, Christa M.

    The U.S. Army Corps of Engineers, Portland District (USACE) conducted the 20-year Columbia River Channel Improvement Project (CRCIP) to deepen the navigation channel between Portland, Oregon, and the Pacific Ocean to allow transit of fully loaded Panamax ships (100 ft wide, 600 to 700 ft long, and draft 45 to 50 ft). In the vicinity of Warrior Point, between river miles (RM) 87 and 88 near St. Helens, Oregon, the USACE conducted underwater blasting and dredging to remove 300,000 yd3 of a basalt rock formation to reach a depth of 44 ft in the Columbia River navigation channel. The purposemore » of this report is to document methods and results of the compliance monitoring study for the blasting project at Warrior Point in the Columbia River.« less

  19. 78 FR 34881 - Special Local Regulations; Marine Events, Wrightsville Channel; Wrightsville Beach, NC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-11

    ...-AA08 Special Local Regulations; Marine Events, Wrightsville Channel; Wrightsville Beach, NC AGENCY... Regulation for the ``Swim the Loop/Motts Channel Sprint'' swim event, to be held on the waters adjacent to... necessary to provide for the safety of life on navigable waters during the event. This action will restrict...

  20. Regional Sediment Management (RSM) Assessment of Longboat Pass, Manatee County, FL

    DTIC Science & Technology

    2016-06-01

    determine the best channel configuration for navigation and most appropriate beneficial use of dredged sediments (the primary criteria used to... channel following the Authorized Channel configuration, and placing sediment on Longboat Key in conjunction with coastal structures to maintain the...use of dredged sediments (the two primary criteria used to evaluate the channel alternatives). RESULTS: Historical and present ebb shoal planform

  1. Investigation on Convergence – Divergence Nozzle Shape for Microscale Channel in Harvesting Kinetic Energy

    NASA Astrophysics Data System (ADS)

    Zakaria, M. S.; Zairi, S.; Misbah, M. N.; Saifizi, M.; Rakawi, Izzudin

    2018-03-01

    This paper presents performance evaluation of nozzle shapes on microscale channel by employing different types of NACA airfoils profile and conventional profile. The deploying nozzle used are NACA 0012, NACA 0021 and NACA 0024 airfoils while for conventional convergence-divergence nozzle diameter ratio (d2 / d1) in the range from 1/4 to 3/4 are applied. These nozzles are assembled on rectangular cross sectional microscale channel which has designated constant fluid flow velocity at the channel inlet. This study revealed reduction on diameter ratio increased dramatically fluid velocity but further reduction on diameter ratio exposed fluid flow to fluctuate which slightly slowing down the fluid velocity. Nevertheless, curved NACA profiles are favourable for convergence – divergence nozzle in microscale channel as it significantly improved flow characteristics by enhancing fluid velocity and resultant kinetic energy as compared to conventional profile.

  2. 33 CFR 239.8 - Cost sharing.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... to provide additional cost sharing to reflect special local benefits or betterments. Such additional... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Cost sharing. 239.8 Section 239.8... RESOURCES POLICIES AND AUTHORITIES: FEDERAL PARTICIPATION IN COVERED FLOOD CONTROL CHANNELS § 239.8 Cost...

  3. 33 CFR 239.4 - Policy.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Policy. 239.4 Section 239.4... RESOURCES POLICIES AND AUTHORITIES: FEDERAL PARTICIPATION IN COVERED FLOOD CONTROL CHANNELS § 239.4 Policy. Projects will be formulated and evaluated in accordance with the policies and procedures described in ER...

  4. 14 CFR 171.45 - Minimum requirements for approval.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the frequency channel is needed for higher priority common system service. [Doc. No. 5034, 29 FR 11337... (CONTINUED) NAVIGATIONAL FACILITIES NON-FEDERAL NAVIGATION FACILITIES Instrument Landing System (ILS... must be met before the FAA will approve an IFR procedure for a non-Federal Instrument Landing System...

  5. 33 CFR 66.10-15 - Aids to navigation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... may be used singly in staggered fashion on alternate sides of the channel provided they are spaced at... should pass between the buoys. (d) Where there is no well-defined channel or when a body of water is...

  6. 33 CFR 66.10-15 - Aids to navigation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... may be used singly in staggered fashion on alternate sides of the channel provided they are spaced at... should pass between the buoys. (d) Where there is no well-defined channel or when a body of water is...

  7. Navigability Potential of Washington Rivers and Streams Determined with Hydraulic Geometry and a Geographic Information System

    USGS Publications Warehouse

    Magirl, Christopher S.; Olsen, Theresa D.

    2009-01-01

    Using discharge and channel geometry measurements from U.S. Geological Survey streamflow-gaging stations and data from a geographic information system, regression relations were derived to predict river depth, top width, and bottom width as a function of mean annual discharge for rivers in the State of Washington. A new technique also was proposed to determine bottom width in channels, a parameter that has received relatively little attention in the geomorphology literature. These regression equations, when combined with estimates of mean annual discharge available in the National Hydrography Dataset, enabled the prediction of hydraulic geometry for any stream or river in the State of Washington. Predictions of hydraulic geometry can then be compared to thresholds established by the Washington State Department of Natural Resources to determine navigability potential of rivers. Rivers with a mean annual discharge of 1,660 cubic feet per second or greater are 'probably navigable' and rivers with a mean annual discharge of 360 cubic feet per second or less are 'probably not navigable'. Variance in the dataset, however, leads to a relatively wide range of prediction intervals. For example, although the predicted hydraulic depth at a mean annual discharge of 1,660 cubic feet per second is 3.5 feet, 90-percent prediction intervals indicate that the actual hydraulic depth may range from 1.8 to 7.0 feet. This methodology does not determine navigability - a legal concept determined by federal common law - instead, this methodology is a tool for predicting channel depth, top width, and bottom width for rivers and streams in Washington.

  8. Ice Formation in Frequently Transited Navigation Channels

    DTIC Science & Technology

    1990-12-01

    measurements made at different sec- The propellers were driven by a 186-W electric tions in the monitoring area. The measurements motor, which is visible in...321. Navigation ConferenceandExhibitionattheFinlandia Mellor, M., Vance, G.P., Wuebben, J.C. and G.E. Hall, Helsinki, Finland, p. 1021-103E Frankenstein

  9. 33 CFR 167.450 - In the Santa Barbara Channel Traffic Separation Scheme: General.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Traffic Separation Scheme: General. 167.450 Section 167.450 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Pacific West Coast § 167.450 In the Santa...

  10. 33 CFR 167.450 - In the Santa Barbara Channel Traffic Separation Scheme: General.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Traffic Separation Scheme: General. 167.450 Section 167.450 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Pacific West Coast § 167.450 In the Santa...

  11. 33 CFR 167.450 - In the Santa Barbara Channel Traffic Separation Scheme: General.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Traffic Separation Scheme: General. 167.450 Section 167.450 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Pacific West Coast § 167.450 In the Santa...

  12. 33 CFR 167.450 - In the Santa Barbara Channel Traffic Separation Scheme: General.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Traffic Separation Scheme: General. 167.450 Section 167.450 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Pacific West Coast § 167.450 In the Santa...

  13. 33 CFR 167.450 - In the Santa Barbara Channel Traffic Separation Scheme: General.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Traffic Separation Scheme: General. 167.450 Section 167.450 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Pacific West Coast § 167.450 In the Santa...

  14. Drivers of barotropic and baroclinic exchange through an estuarine navigation channel in the Mississippi River Delta Plain

    USGS Publications Warehouse

    Snedden, Gregg

    2016-01-01

    Estuarine navigation channels have long been recognized as conduits for saltwater intrusion into coastal wetlands. Salt flux decomposition and time series measurements of velocity and salinity were used to examine salt flux components and drivers of baroclinic and barotropic exchange in the Houma Navigation Channel, an estuarine channel located in the Mississippi River delta plain that receives substantial freshwater inputs from the Mississippi-Atchafalaya River system at its inland extent. Two modes of vertical current structure were identified from the time series data. The first mode, accounting for 90% of the total flow field variability, strongly resembled a barotropic current structure and was coherent with alongshelf wind stress over the coastal Gulf of Mexico. The second mode was indicative of gravitational circulation and was linked to variability in tidal stirring and the horizontal salinity gradient along the channel’s length. Tidal oscillatory salt flux was more important than gravitational circulation in transporting salt upestuary, except over equatorial phases of the fortnightly tidal cycle during times when river inflows were minimal. During all tidal cycles sampled, the advective flux, driven by a combination of freshwater discharge and wind-driven changes in storage, was the dominant transport term, and net flux of salt was always out of the estuary. These findings indicate that although human-made channels can effectively facilitate inland intrusion of saline water, this intrusion can be minimized or even reversed when they are subject to significant freshwater inputs.

  15. An analytical solution for Dean flow in curved ducts with rectangular cross section

    NASA Astrophysics Data System (ADS)

    Norouzi, M.; Biglari, N.

    2013-05-01

    In this paper, a full analytical solution for incompressible flow inside the curved ducts with rectangular cross-section is presented for the first time. The perturbation method is applied to solve the governing equations and curvature ratio is considered as the perturbation parameter. The previous perturbation solutions are usually restricted to the flow in curved circular or annular pipes related to the overly complex form of solutions or singularity situation for flow in curved ducts with non-circular shapes of cross section. This issue specifies the importance of analytical studies in the field of Dean flow inside the non-circular ducts. In this study, the main flow velocity, stream function of lateral velocities (secondary flows), and flow resistance ratio in rectangular curved ducts are obtained analytically. The effect of duct curvature and aspect ratio on flow field is investigated as well. Moreover, it is important to mention that the current analytical solution is able to simulate the Taylor-Görtler and Dean vortices (vortices in stable and unstable situations) in curved channels.

  16. Endwall shape modification using vortex generators and fences to improve gas turbine cooling and effectiveness

    NASA Astrophysics Data System (ADS)

    Gokce, Zeki Ozgur

    The gas turbine is one of the most important parts of the air-breathing jet engine. Hence, improving its efficiency and rendering it operable under high temperatures are constant goals for the aerospace industry. Two types of flow within the gas turbine are of critical relevance: The flow around the first row of stator blades (also known as the nozzle guide vane blade - NGV) and the cooling flow inside the turbine blade cooling channel. The subject of this thesis work was to search for methods that could improve the characteristics of these two types of flows, thus enabling superior engine performance. The innovative aspect of our work was to apply an endwall shape modification previously employed by non-aerospace industries for cooling applications, to the gas turbine cooling flow which is vital to aerospace propulsion. Since the costs of investigating the possible benefits of any idea via extensive experiments could be quite high, we decided to use computational fluid dynamics (CFD) followed by experimentation as our methodology. We decided to analyze the potential benefits of using vortex generators (VGs) as well as the rectangular endwall fence. Since the pin-fins used in cooling flow are circular cylinders, and since the boundary layer flow is mainly characterized by the leading edge diameter of the NGV blade, we modeled both the pin-fins and the NGV blade as vertical circular cylinders. The baseline case consisted of the cylinder(s) being subjected to cross flow and a certain amount of freestream turbulence. The modifications we made on the endwall consisted of rectangular fences. In the case of the cooling flow, we used triangular shaped, common flow up oriented, delta winglet type vortex generators as well as rectangular endwall fences. The channel contained singular cylinders as well as staggered rows of multiple cylinders. For the NGV flow, a rectangular endwall fence and a singular cylinder were utilized. Using extensive CFD modeling and analysis, we confirmed that placing a rectangular endwall fence upstream of the cylinder created additional turbulent mixing in the domain. This led to increased mixing of the cooler flow in the freestream and the hotter flow near the endwall. As a result, we showed that adding a rectangular fence created a 10% mean heat transfer increase downstream of the cylinder. When vortex generators are used, as the flow passes over the sharp edges of the vortex generators, it separates and continues downstream in a rolling, helical pattern. Combined with the effect generated by the orientation of the vortex generators, this flow structure mixes the higher momentum fluid in the freestream with lower momentum fluid in the boundary layer. Similar turbulent mixing behavior is observed over the entire domain, near the cylinders and the side walls. As a result, the heat transfer levels over the wall surfaces are increased and improved cooling is achieved. The improvements in heat transfer are obtained at the expense of acceptable pressure losses across the cooling channel. When the vortex generators are used, the CFD modeling studies showed that overall heat transfer improvements as high as 27% compared to the baseline case are observed inside a domain containing multiple rows of cylinders. A price in the form of 13% pressure loss increase across the channel is paid for the heat transfer benefits. Experiments conducted in the open loop wind tunnel of the Turbomachinery Aero-Heat Transfer Laboratory of the Department of Aerospace Engineering of Penn State University supported the general positive trend of these findings, with a 14% overall increase in heat transfer over the constant heat flux surface when vortex generators are installed, accompanied by an 8% increase in pressure loss. (Abstract shortened by UMI.)

  17. Fluvial processes and passive rehabilitation of the Lisbon Bottom side-channel chute, Lower Missouri River

    USGS Publications Warehouse

    Jacobson, Robert B.; Laustrup, Mark S.; Chapman, Michael D.

    2001-01-01

    Multiple large floods in 1993-1997 on the Lower Missouri River carved a side-channel chute through the river bottom at Lisbon, Missouri. Although similar in some respects to engineered side-channel chutes designed for habitat rehabilitation projects, the Lisbon Bottom chute has been unique in that it was allowed to evolve for more than four years with minimal stabilization. During the wet years, 1996-1999, the chute was subjected to abnormally high discharges and passed as much as 20% of the total discharge of the Missouri River. Relatively unrestrained fluvial processes during this time created a wide channel with highly diverse habitats. The upper one-half of the chute established a shallow, braided channel morphology similar to the pre-managed Missouri River. The lower half established a dynamically migrating, single-thread channel, and an incipient flood plain. Compared to the adjacent navigation channel, the chute established substantial areas of shallow, slow-velocity aquatic habitat that is considered to be in short supply in the present-day Lower Missouri River. The shortterm biological benefits have been mixed: the chute has fewer waterbird and benthic macroinvertebrate taxa than adjacent riverine habitats, but greater numbers of fish species compared to the navigation channel.

  18. Flame front propagation in a channel with porous walls

    NASA Astrophysics Data System (ADS)

    Golovastov, S. V.; Bivol, G. Yu

    2016-11-01

    Propagation of the detonation front in hydrogen-air mixture was investigated in rectangular cross-section channels with sound-absorbing boundaries. The front of luminescence was detected in a channel with acoustically absorbing walls as opposed to a channel with solid walls. Flame dynamics was recorded using a high-speed camera. The flame was observed to have a V-shaped profile in the acoustically absorbing section. The possible reason for the formation of the V-shaped flame front is friction under the surface due to open pores. In these shear flows, the kinetic energy of the flow on the surface can be easily converted into heat. A relatively small disturbance may eventually lead to significant local stretching of the flame front surface. Trajectories of the flame front along the axis and the boundary are presented for solid and porous surfaces.

  19. Study on the influence of supplying compressed air channels and evicting channels on pneumatical oscillation systems for vibromooshing

    NASA Astrophysics Data System (ADS)

    Glăvan, D. O.; Radu, I.; Babanatsas, T.; Babanatis Merce, R. M.; Kiss, I.; Gaspar, M. C.

    2018-01-01

    The paper presents a pneumatic system with two oscillating masses. The system is composed of a cylinder (framework) with mass m1, which has a piston with mass m2 inside. The cylinder (framework system) has one supplying channel for compressed air and one evicting channel for each work chamber (left and right of the piston). Functionality of the piston position comparatively with the cylinder (framework) is possible through the supplying or evicting of compressed air. The variable force that keeps the movement depends on variation of the pressure that is changing depending on the piston position according to the cylinder (framework) and to the section form that is supplying and evicting channels with compressed air. The paper presents the physical model/pattern, the mathematical model/pattern (differential equations) and numerical solution of the differential equations in hypothesis with the section form of supplying and evicting channels with compressed air is rectangular (variation linear) or circular (variation nonlinear).

  20. Quasistatic packings of droplets in flat microfluidic channels

    NASA Astrophysics Data System (ADS)

    Kadivar, Erfan

    2016-02-01

    As observed in recent experiments, monodisperse droplets self-assemble spontaneously in different ordered packings. In this work, we present a numerical study of the droplet packings in the flat rectangular microfluidic channels. Employing the boundary element method, we numerically solve the Stokes equation in two-dimension and investigate the appearance of droplet packing and transition between one and two-row packings of monodisperse emulsion droplets. By calculating packing force applied on the droplet interface, we investigate the effect of flow rate, droplet size, and surface tension on the packing configurations of droplets and transition between different topological packings.

  1. Fuel cell stack with passive air supply

    DOEpatents

    Ren, Xiaoming; Gottesfeld, Shimshon

    2006-01-17

    A fuel cell stack has a plurality of polymer electrolyte fuel cells (PEFCs) where each PEFC includes a rectangular membrane electrode assembly (MEA) having a fuel flow field along a first axis and an air flow field along a second axis perpendicular to the first axis, where the fuel flow field is long relative to the air flow field. A cathode air flow field in each PEFC has air flow channels for air flow parallel to the second axis and that directly open to atmospheric air for air diffusion within the channels into contact with the MEA.

  2. A multi-channel coronal spectrophotometer.

    NASA Technical Reports Server (NTRS)

    Landman, D. A.; Orrall, F. Q.; Zane, R.

    1973-01-01

    We describe a new multi-channel coronal spectrophotometer system, presently being installed at Mees Solar Observatory, Mount Haleakala, Maui. The apparatus is designed to record and interpret intensities from many sections of the visible and near-visible spectral regions simultaneously, with relatively high spatial and temporal resolution. The detector, a thermoelectrically cooled silicon vidicon camera tube, has its central target area divided into a rectangular array of about 100,000 pixels and is read out in a slow-scan (about 2 sec/frame) mode. Instrument functioning is entirely under PDP 11/45 computer control, and interfacing is via the CAMAC system.

  3. Effect of confinements: Bending in Paramecium

    NASA Astrophysics Data System (ADS)

    Eddins, Aja; Yang, Sung; Spoon, Corrie; Jung, Sunghwan

    2012-02-01

    Paramecium is a unicellular eukaryote which by coordinated beating of cilia, generates metachronal waves which causes it to execute a helical trajectory. We investigate the swimming parameters of the organism in rectangular PDMS channels and try to quantify its behavior. Surprisingly a swimming Paramecium in certain width of channels executes a bend of its flexible body (and changes its direction of swimming) by generating forces using the cilia. Considering a simple model of beam constrained between two walls, we predict the bent shapes of the organism and the forces it exerts on the walls. Finally we try to explain how bending (by sensing) can occur in channels by conducting experiments in thin film of fluid and drawing analogy to swimming behavior observed in different cases.

  4. 33 CFR 110.193 - Tampa Bay, Fla.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... anchorage east of Mullet Key. A rectangular area in Tampa Bay, approximately 4,459 yards long and 1,419... 400 feet west of Cut “D” Channel at a point beginning at latitude 27°54′34″, longitude 82°26′35... anchorage east of Mullet Key shall be used by vessels awaiting loading or unloading at Port Tampa that have...

  5. 33 CFR 110.193 - Tampa Bay, Fla.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... anchorage east of Mullet Key. A rectangular area in Tampa Bay, approximately 4,459 yards long and 1,419... 400 feet west of Cut “D” Channel at a point beginning at latitude 27°54′34″, longitude 82°26′35... anchorage east of Mullet Key shall be used by vessels awaiting loading or unloading at Port Tampa that have...

  6. 33 CFR 110.193 - Tampa Bay, Fla.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... anchorage east of Mullet Key. A rectangular area in Tampa Bay, approximately 4,459 yards long and 1,419... 400 feet west of Cut “D” Channel at a point beginning at latitude 27°54′34″, longitude 82°26′35... anchorage east of Mullet Key shall be used by vessels awaiting loading or unloading at Port Tampa that have...

  7. 33 CFR 110.193 - Tampa Bay, Fla.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... anchorage east of Mullet Key. A rectangular area in Tampa Bay, approximately 4,459 yards long and 1,419... 400 feet west of Cut “D” Channel at a point beginning at latitude 27°54′34″, longitude 82°26′35... anchorage east of Mullet Key shall be used by vessels awaiting loading or unloading at Port Tampa that have...

  8. 33 CFR 110.193 - Tampa Bay, Fla.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... anchorage east of Mullet Key. A rectangular area in Tampa Bay, approximately 4,459 yards long and 1,419... 400 feet west of Cut “D” Channel at a point beginning at latitude 27°54′34″, longitude 82°26′35... anchorage east of Mullet Key shall be used by vessels awaiting loading or unloading at Port Tampa that have...

  9. Evaluation of the influence of bottom roughness on parameters of wave flows in channels

    NASA Astrophysics Data System (ADS)

    Valov, A. O.; Degtyarev, V. V.; Fedorova, N. N.

    2018-03-01

    In this paper, a comparative analysis of the results of numerical and experimental studies of the parameters of displacement waves in trays of a rectangular cross-sectional shape with different bottom roughness is performed with the "instantaneous" elimination of the obstacle creating the initial level difference. The program ANSYS complex is used in work.

  10. 33 CFR 239.7 - Separation of flood control works from urban drainage.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Separation of flood control works... OF THE ARMY, DEPARTMENT OF DEFENSE WATER RESOURCES POLICIES AND AUTHORITIES: FEDERAL PARTICIPATION IN COVERED FLOOD CONTROL CHANNELS § 239.7 Separation of flood control works from urban drainage. Covered...

  11. 33 CFR 110.193a - St. Joseph Bay, Fla.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false St. Joseph Bay, Fla. 110.193a... ANCHORAGE REGULATIONS Anchorage Grounds § 110.193a St. Joseph Bay, Fla. (a) The anchorage grounds—(1... northeast of the north entrance channel to Port St. Joe, Florida. (2) Explosives Anchorage Area 2. A...

  12. 33 CFR 164.43 - Automatic Identification System Shipborne Equipment-Prince William Sound.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (AISSE) system consisting of a: (1) Twelve-channel all-in-view Differential Global Positioning System (d... to indicate to shipboard personnel that the U.S. Coast Guard dGPS system cannot provide the required... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Automatic Identification System...

  13. 33 CFR 239.6 - Level of protection.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Level of protection. 239.6... § 239.6 Level of protection. Evaluation of the above items may indicate that submergence of entrances to covered channels may have significant impacts on the level of flooding. The requirements of EO 11988 and...

  14. 33 CFR 207.440 - St. Marys Falls Canal and Locks, Mich.; use, administration, and navigation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... United States part and other lands, piers, buildings, water level regulation works, hydroelectric power plant, and other appurtenances acquired or constructed for the channel improvement and use of the...) Manning requirements. On all vessels of 400 gross tons or over navigating the canal under their own power...

  15. 33 CFR 207.440 - St. Marys Falls Canal and Locks, Mich.; use, administration, and navigation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... United States part and other lands, piers, buildings, water level regulation works, hydroelectric power plant, and other appurtenances acquired or constructed for the channel improvement and use of the...) Manning requirements. On all vessels of 400 gross tons or over navigating the canal under their own power...

  16. 33 CFR 165.709 - Security Zone; Charleston Harbor, Cooper River, South Carolina.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... desiring to transit the Regulated Area may contact the Captain of the Port via VHF-FM channel 16 or by..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY REGULATED NAVIGATION AREAS AND LIMITED ACCESS AREAS Specific Regulated Navigation Areas and Limited Access Areas Seventh Coast Guard District...

  17. 75 FR 23206 - Safety Zone; AVI September Fireworks Display, Laughlin, NV

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-03

    ...-AA00 Safety Zone; AVI September Fireworks Display, Laughlin, NV AGENCY: Coast Guard, DHS. ACTION... the lower Colorado River, Laughlin, NV, in support of a fireworks display near the AVI Resort and... navigable waters of the Lower Colorado River in support of a fireworks show in the navigation channel of the...

  18. 76 FR 57910 - Regulated Navigation Area; Route 24 Bridge Construction, Tiverton and Portsmouth, RI

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-19

    ...-AA11 Regulated Navigation Area; Route 24 Bridge Construction, Tiverton and Portsmouth, RI AGENCY: Coast... surrounding construction of the new Route 24 bridge that crosses the Sakonnet River between Tiverton and... channel beneath the bridge, speed restrictions, and suspension of all vessel traffic within the RNA during...

  19. 78 FR 23515 - Regulated Navigation Areas, Security Zones: Dignitary Arrival/Departure and United Nations...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-19

    ... security zones as RNAs. The Marine Air Terminal, United Nations, and United Nations West Channel Closure... United Nations General Assembly RNA Regulated Navigation Area UN United Nations A. Public Participation... comment, it will be considered as having been received by the Coast Guard when it is received at the...

  20. 33 CFR 165.767 - Security Zone; Manbirtee Key, Port of Manatee, Florida.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., Port of Manatee, Florida. 165.767 Section 165.767 Navigation and Navigable Waters COAST GUARD... § 165.767 Security Zone; Manbirtee Key, Port of Manatee, Florida. (a) Regulated area. The following area... extending 500 yards from the island's shoreline, in all directions, not to include the Port Manatee Channel...

  1. 33 CFR 165.767 - Security Zone; Manbirtee Key, Port of Manatee, Florida.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., Port of Manatee, Florida. 165.767 Section 165.767 Navigation and Navigable Waters COAST GUARD... § 165.767 Security Zone; Manbirtee Key, Port of Manatee, Florida. (a) Regulated area. The following area... extending 500 yards from the island's shoreline, in all directions, not to include the Port Manatee Channel...

  2. 33 CFR 165.767 - Security Zone; Manbirtee Key, Port of Manatee, Florida.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., Port of Manatee, Florida. 165.767 Section 165.767 Navigation and Navigable Waters COAST GUARD... § 165.767 Security Zone; Manbirtee Key, Port of Manatee, Florida. (a) Regulated area. The following area... extending 500 yards from the island's shoreline, in all directions, not to include the Port Manatee Channel...

  3. 33 CFR 165.767 - Security Zone; Manbirtee Key, Port of Manatee, Florida.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., Port of Manatee, Florida. 165.767 Section 165.767 Navigation and Navigable Waters COAST GUARD... § 165.767 Security Zone; Manbirtee Key, Port of Manatee, Florida. (a) Regulated area. The following area... extending 500 yards from the island's shoreline, in all directions, not to include the Port Manatee Channel...

  4. Evaluation of Channel Infill Processes in Relation to Forcing Data

    DTIC Science & Technology

    2016-05-01

    processes that influence channel shoaling, and the site- specific conditions, are also valuable when attempting to predict what type of sediment will...need to be removed in the next dredge cycle as well as where in the channel the sediment is likely to accumulate. This knowledge is helpful in planning...directly related to sediment load and is often the source of cohesive sediments that are transported downstream to navigation channels , harbors, and

  5. Advancing Underwater Acoustic Communication for Autonomous Distributed Networks via Sparse Channel Sensing, Coding, and Navigation Support

    DTIC Science & Technology

    2014-09-30

    underwater acoustic communication technologies for autonomous distributed underwater networks , through innovative signal processing, coding, and...4. TITLE AND SUBTITLE Advancing Underwater Acoustic Communication for Autonomous Distributed Networks via Sparse Channel Sensing, Coding, and...coding: 3) OFDM modulated dynamic coded cooperation in underwater acoustic channels; 3 Localization, Networking , and Testbed: 4) On-demand

  6. Nature of flow and turbulence structure around an in-stream vertical plate in a shallow channel and the implications for sediment erosion

    NASA Astrophysics Data System (ADS)

    Kirkil, Gokhan; Constantinescu, George

    2009-06-01

    Detailed knowledge of the dynamics of large-scale turbulence structures is needed to understand the geomorphodynamic processes around in-stream obstacles present in rivers. Detached Eddy Simulation is used to study the flow past a high-aspect-ratio rectangular cylinder (plate) mounted on a flat-bed relatively shallow channel at a channel Reynolds number of 2.4 × 105. Similar to other flows past surface-mounted bluff bodies, the large amplification of the turbulence inside the horseshoe vortex system is because the core of the main necklace vortex is subject to large-scale bimodal oscillations. The presence of a sharp edge at the flanks of the obstruction fixes the position of the flow separation at all depths and induces the formation and shedding of very strong wake rollers over the whole channel depth. Compared with the case of a circular cylinder where the intensity of the rollers decays significantly in the near-bed region because the incoming flow velocity is not sufficient to force the wake to transition from subcritical to supercritical regime, in the case of a high-aspect-ratio rectangular cylinder the passage of the rollers was found to induce high bed-shear stresses at large distances (6-8 D) behind the obstruction. Also, the nondimensional values of the pressure root-mean-square fluctuations at the bed were found to be about 1 order of magnitude higher than the ones predicted for circular cylinders. Overall, this shows that the shape of the in-stream obstruction can greatly modify the dynamics of the large-scale coherent structures, the nature of their interactions, and ultimately, their capability to entrain and transport sediment particles and the speed at which the scour process evolves during its initial stages.

  7. Pure axial flow of viscoelastic fluids in rectangular microchannels under combined effects of electro-osmosis and hydrodynamics

    NASA Astrophysics Data System (ADS)

    Reshadi, Milad; Saidi, Mohammad Hassan; Ebrahimi, Abbas

    2018-02-01

    This paper presents an analysis of the combined electro-osmotic and pressure-driven axial flows of viscoelastic fluids in a rectangular microchannel with arbitrary aspect ratios. The rheological behavior of the fluid is described by the complete form of Phan-Thien-Tanner (PTT) model with the Gordon-Schowalter convected derivative which covers the upper convected Maxwell, Johnson-Segalman and FENE-P models. Our numerical simulation is based on the computation of 2D Poisson-Boltzmann, Cauchy momentum and PTT constitutive equations. The solution of these governing nonlinear coupled set of equations is obtained by using the second-order central finite difference method in a non-uniform grid system and is verified against 1D analytical solution of the velocity profile with less than 0.06% relative error. Also, a parametric study is carried out to investigate the effect of channel aspect ratio (width to height), wall zeta potential and the Debye-Hückel parameter on 2D velocity profile, volumetric flow rate and the Poiseuille number in the mixed EO/PD flows of viscoelastic fluids with different Weissenberg numbers. Our results show that, for low channel aspect ratios, the previous 1D analytical models underestimate the velocity profile at the channel half-width centerline in the case of favorable pressure gradients and overestimate it in the case of adverse pressure gradients. The results reveal that the inapplicability of the Debye-Hückel approximation at high zeta potentials is more significant for higher Weissenberg number fluids. Also, it is found that, under the specified values of electrokinetic parameters, there is a threshold for velocity scale ratio in which the Poiseuille number is approximately independent of channel aspect ratio.

  8. Convective flows of generalized time-nonlocal nanofluids through a vertical rectangular channel

    NASA Astrophysics Data System (ADS)

    Ahmed, Najma; Vieru, Dumitru; Fetecau, Constantin; Shah, Nehad Ali

    2018-05-01

    Time-nonlocal generalized model of the natural convection heat transfer and nanofluid flows through a rectangular vertical channel with wall conditions of the Robin type are studied. The generalized mathematical model with time-nonlocality is developed by considering the fractional constitutive equations for the shear stress and thermal flux defined with the time-fractional Caputo derivative. The Caputo power-law non-local kernel provides the damping to the velocity and temperature gradient; therefore, transport processes are influenced by the histories at all past and present times. Analytical solutions for dimensionless velocity and temperature fields are obtained by using the Laplace transform coupled with the finite sine-cosine Fourier transform which is suitable to problems with boundary conditions of the Robin type. Particularizing the fractional thermal and velocity parameters, solutions for three simplified models are obtained (classical linear momentum equation with damped thermal flux; fractional shear stress constitutive equation with classical Fourier's law for thermal flux; classical shear stress and thermal flux constitutive equations). It is found that the thermal histories strongly influence the thermal transport for small values of time t. Also, the thermal transport can be enhanced if the thermal fractional parameter decreases or by increasing the nanoparticles' volume fraction. The velocity field is influenced on the one hand by the temperature of the fluid and on the other by the damping of the velocity gradient introduced by the fractional derivative. Also, the transport motions of the channel walls influence the motion of the fluid layers located near them.

  9. Numerical simulation for the magnetic force distribution in electromagnetic forming of small size flat sheet

    NASA Astrophysics Data System (ADS)

    Chen, Xiaowei; Wang, Wenping; Wan, Min

    2013-12-01

    It is essential to calculate magnetic force in the process of studying electromagnetic flat sheet forming. Calculating magnetic force is the basis of analyzing the sheet deformation and optimizing technical parameters. Magnetic force distribution on the sheet can be obtained by numerical simulation of electromagnetic field. In contrast to other computing methods, the method of numerical simulation has some significant advantages, such as higher calculation accuracy, easier using and other advantages. In this paper, in order to study of magnetic force distribution on the small size flat sheet in electromagnetic forming when flat round spiral coil, flat rectangular spiral coil and uniform pressure coil are adopted, the 3D finite element models are established by software ANSYS/EMAG. The magnetic force distribution on the sheet are analyzed when the plane geometries of sheet are equal or less than the coil geometries under fixed discharge impulse. The results showed that when the physical dimensions of sheet are less than the corresponding dimensions of the coil, the variation of induced current channel width on the sheet will cause induced current crowding effect that seriously influence the magnetic force distribution, and the degree of inhomogeneity of magnetic force distribution is increase nearly linearly with the variation of induced current channel width; the small size uniform pressure coil will produce approximately uniform magnetic force distribution on the sheet, but the coil is easy to early failure; the desirable magnetic force distribution can be achieved when the unilateral placed flat rectangular spiral coil is adopted, and this program can be take as preferred one, because the longevity of flat rectangular spiral coil is longer than the working life of small size uniform pressure coil.

  10. 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.

  11. Axially Tapered And Bilayer Microchannels For Evaporative Cooling Devices

    DOEpatents

    Nilson, Robert; Griffiths, Stewart

    2005-10-04

    The invention consists of an evaporative cooling device comprising one or more microchannels whose cross section is axially reduced to control the maximum capillary pressure differential between liquid and vapor phases. In one embodiment, the evaporation channels have a rectangular cross section that is reduced in width along a flow path. In another embodiment, channels of fixed width are patterned with an array of microfabricated post-like features such that the feature size and spacing are gradually reduced along the flow path. Other embodiments incorporate bilayer channels consisting of an upper cover plate having a pattern of slots or holes of axially decreasing size and a lower fluid flow layer having channel widths substantially greater than the characteristic microscale dimensions of the patterned cover plate. The small dimensions of the cover plate holes afford large capillary pressure differentials while the larger dimensions of the lower region reduce viscous flow resistance.

  12. Dynamic film thickness between bubbles and wall in a narrow channel

    NASA Astrophysics Data System (ADS)

    Ito, Daisuke; Damsohn, Manuel; Prasser, Horst-Michael; Aritomi, Masanori

    2011-09-01

    The present paper describes a novel technique to characterize the behavior of the liquid film between gas bubbles and the wall in a narrow channel. The method is based on the electrical conductance. Two liquid film sensors are installed on both opposite walls in a narrow rectangular channel. The liquid film thickness underneath the gas bubbles is recorded by the first sensor, while the void fraction information is obtained by measuring the conductance between the pair of opposite sensors. Both measurements are taken on a large two-dimensional domain and with a high speed. This makes it possible to obtain the two-dimensional distribution of the dynamic liquid film between the bubbles and the wall. In this study, this method was applied to an air-water flow ranging from bubbly to churn regimes in the narrow channel with a gap width of 1.5 mm.

  13. An experimental investigation of the cooling channel geometry effects on the internal forced convection of liquid methane

    NASA Astrophysics Data System (ADS)

    Trejo, Adrian

    Rocket engine fuel alternatives have been an area of discussion for use in high performance engines and deep spaceflight missions. In particular, LCH4 has showed promise as an alternative option in regeneratively cooled rocket engines due to its non-toxic nature, similar storage temperatures to liquid oxygen, and its potential as an in situ resource. However, data pertaining to the heat transfer characteristics of LCH4 is limited. For this reason, a High Heat Transfer Test Facility (HHTTF) at the University of Texas at El Paso's (UTEP) Center for Space Exploration Technology and Research has been developed for the purpose of flowing LCH4 through several heated tube geometry designs subjected to a constant heat flux. In addition, a Methane Condensing Unit (MCU) is integrated to the system setup to supply LCH4 to the test facility. Through the use of temperature and pressure measurements, this experiment will serve not only to study the heat transfer characteristics of LCH4; it serves as a method of simulating the cooling channels of a regeneratively cooled rocket engine at a subscale level. The cross sections for the cooling channels investigated are a 1.8 mm x 1.8 mm square channel, 1.8 mm x 4.1 mm rectangular channel, 3.2 mm and 6.34 mm inside diameter channel, and a 1.8 mm x 14.2 mm high aspect ratio cooling channel (HARCC). The test facility is currently designed for test pressures between 1.03 MPa to 2.06 MPa and heat fluxes up to 5 MW/m2. Results show that at the given test pressures, the Reynolds number reaches up to 140,000 for smaller cooling channels (3.2 mm diameter tube and 1.8 mm x 4.1 mm rectangle) while larger cooling channel geometries (6.35 mm diameter and HARCC) reached Reynolds number around 70,000. Nusselt numbers reached as high as 320 and 265 for a 3.2 mm diameter tube and 1.8 mm x 4.1 mm rectangular channel respectively. For cooling channel geometries with 6.35 mm diameter and HARCC geometry, Nusselt numbers reached 136 (excluding an outlier) and 106 respectively. Heat transfer predictions applied to the data yielded theoretical correlations within 40% of the experimental data. However, typical theoretical values fall within 10%-15% of the experimental values showing agreeable correlations and supporting theories stated in the present study.

  14. Evaluation of the Use of a Bedleveler to Improve Navigability of Atchafalaya River Bar Channel Fluid Mud

    DTIC Science & Technology

    2017-08-01

    3 Channel fluid mud surveying ...density horizons (a) and the 50 Pa horizon depths (b), computed for all 10 surveys . .......................................................... 12... surveyed 11 November 2011. Red trace 1.300 g/ figure cm3 horizon surveyed 4 December 2011

  15. 75 FR 22524 - Ocean Dumping; Designation of Ocean Dredged Material Disposal Sites Offshore of the Siuslaw River...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-29

    ... location to dispose of material dredged from the Siuslaw River navigation channel, and to provide a... sediments from Site A back into the dredged channel resulted in a selection of disposal Sites B and C by the... conflicts. The final Sites are located close to the approach to the Siuslaw River entrance channel but are...

  16. Navigation Channel Improvement, Columbia River, Oregon and Washington - Oak Point to Longview Reach, River Miles 53 to 65. Hydraulic Model Investigation.

    DTIC Science & Technology

    1984-09-01

    channel to Mount St. Helens (RM 87) and Rainier , Oregon, (RM 68), respectively. Side channels are located at Cathlamet and Longview. Pu s L 3. The...to 12 u : survey the movable bed consisted of a vertically graduated rod which was referenced to a portable horizontally graduated rail mounted on the

  17. Location and Navigation with Ultra-Wideband Signals

    DTIC Science & Technology

    2012-06-07

    Coherent vs. Noncoherent Combination 26 F Ranging with Multi-Band UWB Signals: Random Phase Ratation 29 F.1 MB-OFDM System Model...adopted to combine the channel information from subbands: the coherent combining and the noncoherent combining. For the coherent combining, estimates of...channel frequency response coefficients for all subbands are jointly used to estimate the time domain channel with Eq. (33). For the noncoherent

  18. 33 CFR 165.100 - Regulated Navigation Area: Navigable waters within the First Coast Guard District.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... destination(s). (C) Current and forecasted weather, including visibility, wind, and sea state for the... visibility, wind, and sea state. This information may be entered in either the voyage plan or towing vessel's log book. (C) The channels of VHF radio to monitor. (D) Other considerations such as availability of...

  19. 33 CFR 165.100 - Regulated Navigation Area: Navigable waters within the First Coast Guard District.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... destination(s). (C) Current and forecasted weather, including visibility, wind, and sea state for the... visibility, wind, and sea state. This information may be entered in either the voyage plan or towing vessel's log book. (C) The channels of VHF radio to monitor. (D) Other considerations such as availability of...

  20. 33 CFR 165.100 - Regulated Navigation Area: Navigable waters within the First Coast Guard District.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... destination(s). (C) Current and forecasted weather, including visibility, wind, and sea state for the... visibility, wind, and sea state. This information may be entered in either the voyage plan or towing vessel's log book. (C) The channels of VHF radio to monitor. (D) Other considerations such as availability of...

  1. Droplet motion in microfluidic networks: Hydrodynamic interactions and pressure-drop measurements

    NASA Astrophysics Data System (ADS)

    Sessoms, D. A.; Belloul, M.; Engl, W.; Roche, M.; Courbin, L.; Panizza, P.

    2009-07-01

    We present experimental, numerical, and theoretical studies of droplet flows in hydrodynamic networks. Using both millifluidic and microfluidic devices, we study the partitioning of monodisperse droplets in an asymmetric loop. In both cases, we show that droplet traffic results from the hydrodynamic feedback due to the presence of droplets in the outlet channels. We develop a recently-introduced phenomenological model [W. Engl , Phys. Rev. Lett. 95, 208304 (2005)] and successfully confront its predictions to our experimental results. This approach offers a simple way to measure the excess hydrodynamic resistance of a channel filled with droplets. We discuss the traffic behavior and the variations in the corresponding hydrodynamic resistance length Ld and of the droplet mobility β , as a function of droplet interdistance and confinement for channels having circular or rectangular cross sections.

  2. Effect of Finite Chemical Reaction Rates on Heat Transfer to the Walls of Combustion-Driven Supersonic MHD Generator Channels

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

    DAILY, J. W. ..; RAEDER, J.; ZANKL, G.

    1974-03-01

    The effect of finite-rate homogeneous chemical reactions on the heat transfer rates to the walls of combustion-driven supersonic MHD generators was investigated. Experiments were performed on a 200 kW(e) combustion generator. The density of the heat flux to the wall was measured at various axial positions along both a circular cross section Hall-type channel and a diagonal wall channel with a rectangular cross section. From the results it was concluded that a substantial decrease in heat transfer rate to the walls of a combustion-driven supersonic MHD power generator was ob served which appears to occur because of chemical nonequilibrium inmore » the developing wall boundary layers. (LCL)« less

  3. Topological transitions in unidirectional flow of nematic liquid crystal

    NASA Astrophysics Data System (ADS)

    Cummings, Linda; Anderson, Thomas; Mema, Ensela; Kondic, Lou

    2015-11-01

    Recent experiments by Sengupta et al. (Phys. Rev. Lett. 2013) revealed interesting transitions that can occur in flow of nematic liquid crystal under carefully controlled conditions within a long microfluidic channel of rectangular cross-section, with homeotropic anchoring at the walls. At low flow rates the director field of the nematic adopts a configuration that is dominated by the surface anchoring, being nearly parallel to the channel height direction over most of the cross-section; but at high flow rates there is a transition to a flow-dominated state, where the director configuration at the channel centerline is aligned with the flow (perpendicular to the channel height direction). We analyze simple channel-flow solutions to the Leslie-Ericksen model for nematics. We demonstrate that two solutions exist, at all flow rates, but that there is a transition between the elastic free energies of these solutions: the anchoring-dominated solution has the lowest energy at low flow rates, and the flow-dominated solution has lowest energy at high flow rates. NSF DMS 1211713.

  4. Structurally compliant rocket engine combustion chamber: Experimental and analytical validation

    NASA Technical Reports Server (NTRS)

    Jankovsky, Robert S.; Arya, Vinod K.; Kazaroff, John M.; Halford, Gary R.

    1994-01-01

    A new, structurally compliant rocket engine combustion chamber design has been validated through analysis and experiment. Subscale, tubular channel chambers have been cyclically tested and analytically evaluated. Cyclic lives were determined to have a potential for 1000 percent increase over those of rectangular channel designs, the current state of the art. Greater structural compliance in the circumferential direction gave rise to lower thermal strains during hot firing, resulting in lower thermal strain ratcheting and longer predicted fatigue lives. Thermal, structural, and durability analyses of the combustion chamber design, involving cyclic temperatures, strains, and low-cycle fatigue lives, have corroborated the experimental observations.

  5. Collapse of Non-Rectangular Channels in a Soft Elastomer

    NASA Astrophysics Data System (ADS)

    Tepayotl-Ramirez, Daniel; Park, Yong-Lae; Lu, Tong; Majidi, Carmel

    2013-03-01

    We examine the collapse of microchannels in a soft elastomer by treating the sidewalls as in- denters that penetrate the channel base. This approach leads to a closed-form algebraic mapping between applied pressure and cross-sectional deformation that are in strong agreement with ex- perimental measurements and Finite Element Analysis (FEA) simulation. Applications of this new approach to modeling soft microchannel collapse range from lab-on-a-chip microfluidics for pressure-controlled protein filtration to soft-matter pressures sensing. We demonstrate the latter by comparing theoretical predictions with experimental measurements of the pressure-controlled electrical resistance of liquid-phase Gallium alloy microchannels embedded in a soft silicone elas- tomer.

  6. Study of the Effects of Centrifugal Instabilities on Flow in a 40 to 1 Aspect Ratio Rectangular Curved Channel, for Dean Numbers from 35 to Fully Turbulent Conditions

    DTIC Science & Technology

    1990-12-01

    is constructed from stainless steel hypodermic tubing with inner and outer diameters of 0.203 mm and 0.406 mm. The five tubes were first joined by...for all channels is 256 kHz. A schematic diagram of the measurement process [Ref. 25] is given in Figure 78, and is also described below. The analog...and smoke rake. Combustion takes place inside a 40.64 cm long, 6.27 cm inside diameter (2.5 inch schedule 40) steel pipe. Inside this chamber, smoke is

  7. Effect of channel size on sweet potato storage root enlargement in the Tuskegee University hydroponic nutrient film system

    NASA Technical Reports Server (NTRS)

    Morris, Carlton E.; Martinez, Edwin; Bonsi, C. K.; Mortley, Desmond G.; Hill, Walter A.; Ogbuehi, Cyriacus R.; Loretan, Phil A.

    1989-01-01

    The potential of the sweet potato as a food source for future long term manned space missions is being evaluated for NASA's Controlled Ecological Life Support Systems (CELSS) program. Sweet potatoes have been successfully grown in a specially designed Tuskegee University nutrient film technique (TU NFT) system. This hydroponic system yielded storage roots as high as 1790 g/plant fresh weight. In order to determine the effect of channel size on the yield of sweet potatoes, the width and depth of the growing channels were varied in two separate experiments. Widths were studied using the rectangular TU NFT channels with widths of 15 cm (6 in), 30 cm (12 in) and 45 cm (18 in). Channel depths of 5 cm (2 in), 10 cm (4 in), and 15 cm (6 in) were studied using a standard NASA fan shaped Biomass Production Chamber (BPC) channel. A comparison of preliminary results indicated that, except for storage root number, the growth and yield of sweet potatoes were not affected by channel width. Storage root yield was affected by channel depth although storage root number and foliage growth were not. Both experiments are being repeated.

  8. Houston-Galveston Navigation Channel Shoaling Study

    DTIC Science & Technology

    2014-12-01

    compared to data collected at other times during the year. If this is the case, sediment would tend to collect farther down the channel toward Red Fish ...27 28 29 30 31 32 33 Location along channel (1000 m increments) Pe rc en t ( % ) Bayport Red Fish Reef Pe rc en t ( % ) ERDC/CHL TR-14-14 12...in the bay tends to evacuate. For the wind and flow conditions that were investigated previously, the net drift in the channel upland from Red Fish

  9. GREAT II (Upper Mississippi River. Guttenberg, Iowa to Saverton, Missouri). Side Channel Work Group Appendix

    DTIC Science & Technology

    1980-12-01

    is current during normal river stage. The graduations in this category are wide- spread, ranging frcm fast flowing watercourses with high banks to...channel category on the other. They may be former side channels that have been cut off, or that have only intermittent flows in them. They may be...navigation project certainly is a contributor by providing a deep channel and an abundance of beaches. Karaki and Van Hoften noted that small, fast

  10. Heat Transport Enhancement of Turbulent Thermal Convection by Inserted Channels

    NASA Astrophysics Data System (ADS)

    Xia, Ke-Qing; Zhang, Lu

    2017-11-01

    We report an experimental study on the heat transport properties of turbulent Rayleigh Benard Convection (RBC) in a rectangular cell with two types of 3D-printed structures inserted inside. The first one splits the original rectangular cell into 60 identical sub cells whose aspect ratio is 1:1:10 (length, width, height). The second one splits the cell into 30 sub cells, each with a 1:2:10 aspect ratio and a baffle in the center. We find that for large Rayleigh numbers (Ra), the Nusselt numbers (Nu) of both structures increase compared with that of the empty rectangular cell. An enhancement in Nu as much as 20% is found for the second type of insertion at Rayleigh number 2 ×109 . Moreover, the Nu-Ra scaling shows a transition with both geometries. The particle image velocimetry (PIV) measurement within a single sub unit indicates that the transition may be related to the laminar to turbulent transition in flow field. Direct numerical simulations (DNS) confirm the experimental results. Our results demonstrate the potential in using insertions to enhance passive heat transfer. This work was supported by the Research Grants Council (RGC) of HKSAR (Nos. CUHK404513 and CUHK14301115).

  11. Disentangling multiple pressures on fish assemblages in large rivers.

    PubMed

    Zajicek, Petr; Radinger, Johannes; Wolter, Christian

    2018-06-15

    European large rivers are exposed to multiple human pressures and maintained as waterways for inland navigation. However, little is known on the dominance and interactions of multiple pressures in large rivers and in particular inland navigation has been ignored in multi-pressure analyzes so far. We determined the response of ten fish population metrics (FPM, related to densities of diagnostic guilds and biodiversity) to 11 prevailing pressures including navigation intensity at 76 sites in eight European large rivers. Thereby, we aimed to derive indicative FPM for the most influential pressures that can serve for fish-based assessments. Pressures' influences, impacts and interactions were determined for each FPM using bootstrapped regression tree models. Increased flow velocity, navigation intensity and the loss of floodplains had the highest influences on guild densities and biodiversity. Interactions between navigation intensity and loss of floodplains and between navigation intensity and increased flow velocity were most frequent, each affecting 80% of the FPM. Further, increased sedimentation, channelization, organic siltation, the presence of artificial embankments and the presence of barriers had strong influences on at least one FPM. Thereby, each FPM was influenced by up to five pressures. However, some diagnostic FPM could be derived: Species richness, Shannon and Simpson Indices, the Fish Region Index and lithophilic and psammophilic guilds specifically indicate rhithralisation of the potamal region of large rivers. Lithophilic, phytophilic and psammophilic guilds indicate disturbance of shoreline habitats through both (i) wave action induced by passing vessels and (ii) hydromorphological degradation of the river channel that comes along with inland navigation. In European large rivers, inland navigation constitutes a highly influential pressure that adds on top of the prevailing hydromorphological degradation. Therefore, river management has to consider river hydromorphology and inland navigation to efficiently rehabilitate the potamal region of large rives. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Bathymetric survey of the Cayuga Inlet flood-control channel and selected tributaries in Ithaca, New York, 2016

    USGS Publications Warehouse

    Wernly, John F.; Nystrom, Elizabeth A.; Coon, William F.

    2017-09-08

    From July 14 to July 20, 2016, the U.S. Geological Survey, in cooperation with the City of Ithaca, New York, and the New York State Department of State, surveyed the bathymetry of the Cayuga Inlet flood-control channel and the mouths of selected tributaries to Cayuga Inlet and Cayuga Lake in Ithaca, N.Y. The flood-control channel, built by the U.S. Army Corps of Engineers between 1965 and 1970, was designed to convey flood flows from the Cayuga Inlet watershed through the City of Ithaca and minimize possible flood damages. Since that time, the channel has infrequently been maintained by dredging, and sediment accumulation and resultant shoaling have greatly decreased the conveyance of the channel and its navigational capability.U.S. Geological Survey personnel collected bathymetric data by using an acoustic Doppler current profiler. The survey produced a dense dataset of water depths that were converted to bottom elevations. These elevations were then used to generate a geographic information system bathymetric surface. The bathymetric data and resultant bathymetric surface show the current condition of the channel and provide the information that governmental agencies charged with maintaining the Cayuga Inlet for flood-control and navigational purposes need to make informed decisions regarding future maintenance measures.

  13. River-corridor habitat dynamics, Lower Missouri River

    USGS Publications Warehouse

    Jacobson, Robert B.

    2010-01-01

    Intensive management of the Missouri River for navigation, flood control, and power generation has resulted in substantial physical changes to the river corridor. Historically, the Missouri River was characterized by a shifting, multithread channel and abundant unvegetated sandbars. The shifting channel provided a wide variety of hydraulic environments and large areas of connected and unconnected off-channel water bodies.Beginning in the early 1800s and continuing to the present, the channel of the Lower Missouri River (downstream from Sioux City, Iowa) has been trained into a fast, deep, single-thread channel to stabilize banks and maintain commercial navigation. Wing dikes now concentrate the flow, and revetments and levees keep the channel in place and disconnect it from the flood plain. In addition, reservoir regulation of the Missouri River upstream of Yankton, South Dakota, has substantially changed the annual hydrograph, sediment loads, temperature regime, and nutrient budgets.While changes to the Missouri River have resulted in broad social and economic benefits, they have also been associated with loss of river-corridor habitats and diminished populations of native fish and wildlife species. Today, Missouri River stakeholders are seeking ways to restore some natural ecosystem benefits of the Lower Missouri River without compromising traditional economic uses of the river and flood plain.

  14. 33 CFR 334.102 - Sandy Hook Bay, Naval Weapons Station EARLE, Piers and Terminal Channel, restricted area...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Sandy Hook Bay, Naval Weapons... DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.102 Sandy Hook Bay, Naval Weapons Station EARLE, Piers..., shall be enforced by the Commanding Officer, Naval Weapons Station Earle, and/or other persons or...

  15. 33 CFR 334.102 - Sandy Hook Bay, Naval Weapons Station EARLE, Piers and Terminal Channel, restricted area...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Sandy Hook Bay, Naval Weapons... DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.102 Sandy Hook Bay, Naval Weapons Station EARLE, Piers..., shall be enforced by the Commanding Officer, Naval Weapons Station Earle, and/or other persons or...

  16. 33 CFR 334.102 - Sandy Hook Bay, Naval Weapons Station EARLE, Piers and Terminal Channel, restricted area...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Sandy Hook Bay, Naval Weapons... DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.102 Sandy Hook Bay, Naval Weapons Station EARLE, Piers..., shall be enforced by the Commanding Officer, Naval Weapons Station Earle, and/or other persons or...

  17. 33 CFR 334.102 - Sandy Hook Bay, Naval Weapons Station EARLE, Piers and Terminal Channel, restricted area...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Sandy Hook Bay, Naval Weapons... DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.102 Sandy Hook Bay, Naval Weapons Station EARLE, Piers..., shall be enforced by the Commanding Officer, Naval Weapons Station Earle, and/or other persons or...

  18. 33 CFR 334.102 - Sandy Hook Bay, Naval Weapons Station EARLE, Piers and Terminal Channel, restricted area...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Sandy Hook Bay, Naval Weapons... DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.102 Sandy Hook Bay, Naval Weapons Station EARLE, Piers..., shall be enforced by the Commanding Officer, Naval Weapons Station Earle, and/or other persons or...

  19. 33 CFR 165.804 - Snake Island, Texas City, Texas; mooring and fleeting of vessels-safety zone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Snake Island, Texas City, Texas... Guard District § 165.804 Snake Island, Texas City, Texas; mooring and fleeting of vessels—safety zone... Turning Basin west of Snake Island; (3) The area of Texas City Channel from the north end of the Turning...

  20. 33 CFR 165.804 - Snake Island, Texas City, Texas; mooring and fleeting of vessels-safety zone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Snake Island, Texas City, Texas... Guard District § 165.804 Snake Island, Texas City, Texas; mooring and fleeting of vessels—safety zone... Turning Basin west of Snake Island; (3) The area of Texas City Channel from the north end of the Turning...

  1. Inertial Navigation System for India's Reusable Launch Vehicle-Technology Demonstrator (RLV-TD HEX) Mission

    NASA Astrophysics Data System (ADS)

    Umadevi, P.; Navas, A.; Karuturi, Kesavabrahmaji; Shukkoor, A. Abdul; Kumar, J. Krishna; Sreekumar, Sreejith; Basim, A. Mohammed

    2017-12-01

    This work presents the configuration of Inertial Navigation System (INS) used in India's Reusable Launch Vehicle-Technology Demonstrator (RLV-TD) Program. In view of the specific features and requirements of the RLV-TD, specific improvements and modifications were required in the INS. A new system was designed, realised and qualified meeting the mission requirements of RLV-TD, at the same time taking advantage of the flight heritage attained in INS through various Launch vehicle Missions of the country. The new system has additional redundancy in acceleration channel, in-built inclinometer based bias update scheme for acceleration channels and sign conventions as employed in an aircraft. Data acquisition in micro cycle periodicity (10 ms) was incorporated which was required to provide rate and attitude information at higher sampling rate for ascent phase control. Provision was incorporated for acquisition of rate and acceleration data with high resolution for aerodynamic characterisation and parameter estimation. GPS aided navigation scheme was incorporated to meet the stringent accuracy requirements of the mission. Navigation system configuration for RLV-TD, specific features incorporated to meet the mission requirements, various tests carried out and performance during RLV-TD flight are highlighted.

  2. Operation and Maintenance, 9-Foot Navigation Channel, Upper Mississippi River, Head of Navigation to Guttenberg, Iowa. Volume 2. Exhibits.

    DTIC Science & Technology

    1974-08-01

    employ methods which differ from those employed by them in the past. This action was commenced on June 19, 1973. There followed certain proceedings in...Sedimentation in Navigation Pools - Trap Efficiency Method 66 67 Textures of Samples from Pools 4, 5, 5A,and 6 67 68- Textures of Samples from Tributary...island and surrounding waters located in the Mississippi River as aforesaid. 15. The method of disposal is such that the spoil material is placed on

  3. A Simplified Analytic Investigation of the Riverside Effects of Sediment Diversions

    DTIC Science & Technology

    2013-09-01

    demonstrated that the river bed consists of a sand layer of variable thickness, underlain by erosion resistant strata (either relict glacial deposits...following analysis. Simplifications and Initial Conditions. Consider a river modeled as a wide rectangular channel of constant width (Figure 1). The...CHETN-VII-13 September 2013 14  Short term effects include the redistribution of sediment by erosion upstream of the diversion to deposition

  4. Time-resolved fast-neutron radiography of air-water two-phase flows in a rectangular channel by an improved detection system

    NASA Astrophysics Data System (ADS)

    Zboray, Robert; Dangendorf, Volker; Mor, Ilan; Bromberger, Benjamin; Tittelmeier, Kai

    2015-07-01

    In a previous work, we have demonstrated the feasibility of high-frame-rate, fast-neutron radiography of generic air-water two-phase flows in a 1.5 cm thick, rectangular flow channel. The experiments have been carried out at the high-intensity, white-beam facility of the Physikalisch-Technische Bundesanstalt, Germany, using an multi-frame, time-resolved detector developed for fast neutron resonance radiography. The results were however not fully optimal and therefore we have decided to modify the detector and optimize it for the given application, which is described in the present work. Furthermore, we managed to improve the image post-processing methodology and the noise suppression. Using the tailored detector and the improved post-processing, significant increase in the image quality and an order of magnitude lower exposure times, down to 3.33 ms, have been achieved with minimized motion artifacts. Similar to the previous study, different two-phase flow regimes such as bubbly slug and churn flows have been examined. The enhanced imaging quality enables an improved prediction of two-phase flow parameters like the instantaneous volumetric gas fraction, bubble size, and bubble velocities. Instantaneous velocity fields around the gas enclosures can also be more robustly predicted using optical flow methods as previously.

  5. Steady boiling of vapor bubbles in rectangular channels

    NASA Astrophysics Data System (ADS)

    Ajaev, Vladimir S.; Homsy, George M.

    2000-11-01

    We consider vapor bubbles in microchannels in which the vapor is produced by a heater element and condenses in cooler parts of the interface. The free boundary problem is formulated for a long steady-state bubble in a rectangular channel with a heated bottom. The shape of the liquid-vapor interface is described using lubrication-type equations in the regime in which the vapor phase fills most of the cross-section. Contact lines may be present, marking the transitions between molecularly thin films and macroscopic ones. The main parameters are the differences between heater, saturation, and top wall temperatures. The equations are solved numerically over a range of parameter values with an integral condition requiring the evaporation near the heater to balance condensation in colder areas of the interface. Depending on the temperature, the side walls can be either dry or covered with a liquid film; we identify criteria for these two different regimes. The asymptotic method breaks down in the limit when capillary condensation becomes important near the bubble top and a different approach is used to determine the shape of the bubble in this limit. Solutions here involve localized regions of large mass fluxes, which are asymptotically matched to capillary-statics regions where the heat transfer is negligible.

  6. A Navigation Safety Support Model for the Strait of Istanbul

    NASA Astrophysics Data System (ADS)

    Yazici, M. Anil; Otay, Emre N.

    In this study, a real time maritime traffic support model is developed for safe navigation in the Strait of Istanbul, also known as the Bosporus. The present model simulates vessel trajectories corresponding to possible headings, using channel geometry, counter traffic, and surface currents as input. A new MATLAB code is developed for the simulation and the Marine GNC Toolbox (Fossen and Perez, 2004) is used for the vessel hydrodynamics and the auto-pilot model. After computing the trajectory tree of the vessel by forward-mapping its position distribution with respect to the initial position vector, the casualty probabilities of each trajectory are found. Within certain restrictions on vessel geometry, the proposed model predicts the safest possible intended course for the transit vessels based on the navigational parameters including position, speed, and course of the vessel. The model is tested for the Strait of Istanbul for validation. Without loss of generality, the model can be used for any narrow channel with a vessel traffic system providing the necessary input.

  7. A regional waterway management system for balancing recreational boating and resource protection.

    PubMed

    Swett, Robert A; Listowski, Charles; Fry, Douglas; Boutelle, Stephen; Fann, David

    2009-06-01

    Florida's coasts have been transformed over the past three decades as population growth and unprecedented demand for individual shore access to bays and estuaries led to the creation of residential canal developments. Thousands of miles of channels and basins were dredged as a by-product of this urbanization process. The navigable waterways that resulted are now being stressed by increasing boat traffic and canal-side activities. Recognizing their common goal to preserve the recreational and ecological value of southwest Florida waterways, the Florida Department of Environmental Protection, the four-county West Coast Inland Navigation District, and the University of Florida Sea Grant College Program signed a Memorandum of Agreement. The signatories agreed to develop a science-based Regional Waterway Management System (RWMS), which is a new approach to waterway planning and permitting based on carefully mapped channel depths, a census of actual boat populations, and the spatial extent of natural resources. The RWMS provides a comprehensive, regional overview of channel conditions and the geographic distribution and severity of existing impediments to safe navigation and resource protection. RWMS information and analyses result in regional-scale permitting to accommodate water-dependent uses while minimizing environmental impacts and reducing public expenditures. Compared with traditional approaches to waterway management, the science-based RWMS is relatively unbiased, objective, transparent, ecologically sound, and fiscally prudent.

  8. Further evidence that rats rely on local rather than global spatial information to locate a hidden goal: reply to Cheng and Gallistel (2005).

    PubMed

    McGregor, Anthony; Jones, Peter M; Good, Mark A; Pearce, John M

    2006-07-01

    Naive male Hooded Lister rats (Rattus norvegicus) were required to find a submerged platform in a right-angled corner between a long and a short wall of a pool in the shape of an irregular pentagon. Tests in a rectangular pool revealed a preference for the corners that corresponded with the correct corner in the pentagon. These findings indicate that rats identified the correct corner in the pentagon by local cues. They contradict the suggestion that rats navigate by moving in a particular direction relative to the principal axis of the shape of their environment.

  9. Generation of a Sediment Rating and Load Curve Demonstrated at the Mackinaw River Confluence

    DTIC Science & Technology

    2016-12-01

    Illinois. The Mackinaw River produces a shoal in the Illinois River that impinges on the navigation channel . The sediment deposition forms a natural...delta that would encroach on the channel if not removed via dredging. However, the sediment has the potential for beneficial use. The Streamside...function for sediment transportation in open channel flows. Technical Bulletin No. 1026. Washington, DC: U.S. Department of Agriculture. ERDC/CHL

  10. Sand Waves That Impede Navigation of Coastal Inlet Navigation Channels

    DTIC Science & Technology

    2006-08-01

    Merrymeeting Bay. The bay collects coarse-grained sediment from unconsolidated ice-contact and periglacial deposits (Fenster and FitzGerald 1996). During...bed, which is a layer of denser or larger sized sediment left after finer material has been winnowed by a strong current, can inhibit bed form...Order Descriptors (important) • Superposition: simple or compound. • Sediment Characteristics (size, sorting). Third Order Descriptors (useful

  11. 33 CFR 207.260 - Yazoo Diversion Canal, Vicksburg, Miss., from its mouth at Kleinston Landing to Fisher Street...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Clay Street) at Vicksburg City Front. No vessel or raft shall be moored along the west bank of the... Street; navigation. (a) Signals. Vessels navigating the canal will be governed by the Pilot Rules for... power to make headway and guide the raft so as to give half the channel to passing vessels. (c) Mooring...

  12. 33 CFR 207.260 - Yazoo Diversion Canal, Vicksburg, Miss., from its mouth at Kleinston Landing to Fisher Street...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Clay Street) at Vicksburg City Front. No vessel or raft shall be moored along the west bank of the... Street; navigation. (a) Signals. Vessels navigating the canal will be governed by the Pilot Rules for... power to make headway and guide the raft so as to give half the channel to passing vessels. (c) Mooring...

  13. 33 CFR 110.74c - Bahia de San Juan, PR.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Bahia de San Juan, PR. 110.74c... ANCHORAGE REGULATIONS Special Anchorage Areas § 110.74c Bahia de San Juan, PR. The waters of San Antonio Channel, Bahia de San Juan, eastward of longitude 66°05′45″ W. [CGD 7-83-29, 49 FR 48540, Dec. 13, 1984] ...

  14. 33 CFR 110.74c - Bahia de San Juan, PR.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Bahia de San Juan, PR. 110.74c... ANCHORAGE REGULATIONS Special Anchorage Areas § 110.74c Bahia de San Juan, PR. The waters of San Antonio Channel, Bahia de San Juan, eastward of longitude 66°05′45″ W. [CGD 7-83-29, 49 FR 48540, Dec. 13, 1984] ...

  15. 33 CFR 117.799 - Long Island, New York Inland Waterway from East Rockaway Inlet to Shinnecock Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Parkway bridge, mile 30.7 across State Boat Channel at Captree Island, shall open on signal if at least... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Long Island, New York Inland... Requirements New York § 117.799 Long Island, New York Inland Waterway from East Rockaway Inlet to Shinnecock...

  16. 33 CFR 117.799 - Long Island, New York Inland Waterway from East Rockaway Inlet to Shinnecock Canal.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Parkway bridge, mile 30.7 across State Boat Channel at Captree Island, shall open on signal if at least... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Long Island, New York Inland... Requirements New York § 117.799 Long Island, New York Inland Waterway from East Rockaway Inlet to Shinnecock...

  17. 33 CFR 117.799 - Long Island, New York Inland Waterway from East Rockaway Inlet to Shinnecock Canal.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Parkway bridge, mile 30.7 across State Boat Channel at Captree Island, shall open on signal if at least... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Long Island, New York Inland... Requirements New York § 117.799 Long Island, New York Inland Waterway from East Rockaway Inlet to Shinnecock...

  18. Numerical solution of a multi-ion one-potential model for electroosmotic flow in two-dimensional rectangular microchannels.

    PubMed

    Van Theemsche, Achim; Deconinck, Johan; Van den Bossche, Bart; Bortels, Leslie

    2002-10-01

    A new more general numerical model for the simulation of electrokinetic flow in rectangular microchannels is presented. The model is based on the dilute solution model and the Navier-Stokes equations and has been implemented in a finite-element-based C++ code. The model includes the ion distribution in the Helmholtz double layer and considers only one single electrical' potential field variable throughout the domain. On a charged surface(s) the surface charge density, which is proportional to the local electrical field, is imposed. The zeta potential results, then, from this boundary condition and depends on concentrations, temperature, ion valence, molecular diffusion coefficients, and geometric conditions. Validation cases show that the model predicts accurately known analytical results, also for geometries having dimensions comparable to the Debye length. As a final study, the electro-osmotic flow in a controlled cross channel is investigated.

  19. Experimental and modeling study of Newtonian and non-Newtonian fluid flow in pore network micromodels.

    PubMed

    Perrin, Christian L; Tardy, Philippe M J; Sorbie, Ken S; Crawshaw, John C

    2006-03-15

    The in situ rheology of polymeric solutions has been studied experimentally in etched silicon micromodels which are idealizations of porous media. The rectangular channels in these etched networks have dimensions typical of pore sizes in sandstone rocks. Pressure drop/flow rate relations have been measured for water and non-Newtonian hydrolyzed-polyacrylamide (HPAM) solutions in both individual straight rectangular capillaries and in networks of such capillaries. Results from these experiments have been analyzed using pore-scale network modeling incorporating the non-Newtonian fluid mechanics of a Carreau fluid. Quantitative agreement is seen between the experiments and the network calculations in the Newtonian and shear-thinning flow regions demonstrating that the 'shift factor,'alpha, can be calculated a priori. Shear-thickening behavior was observed at higher flow rates in the micromodel experiments as a result of elastic effects becoming important and this remains to be incorporated in the network model.

  20. Frequency-Switchable Metamaterial Absorber Injecting Eutectic Gallium-Indium (EGaIn) Liquid Metal Alloy

    PubMed Central

    Ling, Kenyu; Kim, Hyung Ki; Yoo, Minyeong; Lim, Sungjoon

    2015-01-01

    In this study, we demonstrated a new class of frequency-switchable metamaterial absorber in the X-band. Eutectic gallium-indium (EGaIn), a liquid metal alloy, was injected in a microfluidic channel engraved on polymethyl methacrylate (PMMA) to achieve frequency switching. Numerical simulation and experimental results are presented for two cases: when the microfluidic channels are empty, and when they are filled with liquid metal. To evaluate the performance of the fabricated absorber prototype, it is tested with a rectangular waveguide. The resonant frequency was successfully switched from 10.96 GHz to 10.61 GHz after injecting liquid metal while maintaining absorptivity higher than 98%. PMID:26561815

  1. Guidance for Subaqueous Dredged Material Capping.

    DTIC Science & Technology

    1998-06-01

    from Ambrose Channel , over the contaminated sediments. At least two intermediate sur- veys and additional capping were required before capping was...organisms to a given bioturbation depth; reducing contami- nant flux rates to achieve specific sediment, pore water, or water column target...bathymetry, bottom slopes, cur- rents, water depths, water column density stratification, erosion/accretion trends, proximity to navigation channels

  2. Patchogue River, Westbrook, Connecticut. Small Navigation Project, Detailed Project Report and Environmental Assessment.

    DTIC Science & Technology

    1982-12-01

    Westbrook, especially if channel modifications are undertaken. Currently, local entrepreneurs are planning to construct new power- boat facilities...result. Value of Delay Time Existing S14,400 W/Plan B 7,200 PLAN B: Annual Benefit = S 7,200 PLAN C Plan C would increse the width of the existing channel

  3. 78 FR 33219 - Special Local Regulations; Swim Across the Potomac, Potomac River; National Harbor Access Channel...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-04

    ... Channel, MD AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is... provide for the safety of life on navigable waters during the event. This action is intended to temporarily restrict vessel traffic in a portion of the Potomac River during the event. DATES: This rule is...

  4. 33 CFR 334.783 - Arlington Channel, U.S. Coast Guard Base Mobile, Mobile, Alabama, Coast Guard restricted area.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Guard Base Mobile, Mobile, Alabama, Coast Guard restricted area. 334.783 Section 334.783 Navigation and... RESTRICTED AREA REGULATIONS § 334.783 Arlington Channel, U.S. Coast Guard Base Mobile, Mobile, Alabama, Coast... without prior approval from the Commanding Officer, U.S. Coast Guard Group Mobile or his designated...

  5. PLASTIC-SASS--A COMPUTER PROGRAM FOR STRESSES AND DEFLECTIONS IN A REACTOR SUBASSEMBLY UNDER THERMAL, HYDRAULIC, AND FUEL EXPANSION LOADS

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

    Friedrich, C.M.

    1963-05-01

    PLASTlC-SASS, an ALTAC-3 computer program that determines stresses and deflections in a flat-plate, rectangular reactor subassembly is described. Elastic, plastic, and creep properties are used to calculate the results of temperature, pressure, and fuel expansion. Plate deflections increase or decrease local channel thicknesses and thus produce a hydraulic load which is a function of fuel plate deflection. (auth)

  6. Near-wall turbulence alteration through thin streamwise riblets

    NASA Technical Reports Server (NTRS)

    Wilkinson, Stephen P.; Lazos, Barry S.

    1987-01-01

    The possibility of improving the level of drag reduction associated with near-wall riblets is considered. The methodology involves the use of a hot-wire anemometer to study various surface geometries on small, easily constructed models. These models consist of small, adjacent rectangular channels on the wall aligned in the streamwise direction. The VITA technique is modified and applied to thin-element-array and smooth flat-plate data and the results are indicated schematically.

  7. Flow and Thermal Performance of a Water-Cooled Periodic Transversal Elliptical Microchannel Heat Sink for Chip Cooling.

    PubMed

    Wei, Bo; Yang, Mo; Wang, Zhiyun; Xu, Hongtao; Zhang, Yuwen

    2015-04-01

    Flow and thermal performance of transversal elliptical microchannels were investigated as a passive scheme to enhance the heat transfer performance of laminar fluid flow. The periodic transversal elliptical micro-channel is designed and its pressure drop and heat transfer characteristics in laminar flow are numerically investigated. Based on the comparison with a conventional straight micro- channel having rectangular cross section, it is found that periodic transversal elliptical microchannel not only has great potential to reduce pressure drop but also dramatically enhances heat transfer performance. In addition, when the Reynolds number equals to 192, the pressure drop of the transversal elliptical channel is 36.5% lower than that of the straight channel, while the average Nusselt number is 72.8% higher; this indicates that the overall thermal performance of the periodic transversal elliptical microchannel is superior to the conventional straight microchannel. It is suggested that such transversal elliptical microchannel are attractive candidates for cooling future electronic chips effectively with much lower pressure drop.

  8. Present understanding of MHD and heat transfer phenomena for liquid metal blankets

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

    Kirillov, I.R.; Barleon, L.; Reed, C.B.

    1994-07-01

    A review of experimental work on magnetohydrodynamic (MHD) and heat transfer (HT) characteristics of liquid metal flows in fusion relevant conditions is presented. Experimental data on MHD flow pressure drop in straight channels of round and rectangular cross-section with electroconducting walls in a transverse magnetic field show good agreement with theoretical predictions, and simple engineering formulas are confirmed. Less data are available on velocity distribution and HT characteristics, and even less data are available for channels with electroinsulating walls or artificially made self-heating electroinsulating coatings. Some experiments show an interesting phenomena of HT increase in the presence of a transversemore » or axial magnetic field. For channels of complex geometry -- expansions, contractions, bends, and manifolds -- few experimental data are available. Future efforts should be directed toward investigation of MHD/HT in straight channels with perfect and nonperfect electroinsulated walls, including walls with controlled imperfections, and in channels of complex geometry. International cooperation in manufacturing and operating experimental facilities with magnetic fields at, or even higher than, 5--7 T with comparatively large volumes may be of great help.« less

  9. Visualization of Secondary Flow Development in High Aspect Ratio Channels with Curvature

    NASA Technical Reports Server (NTRS)

    Meyer, Michael L.; Giuliani, James E.

    1994-01-01

    The results of an experimental project to visually examine the secondary flow structure that develops in curved, high aspect-ratio rectangular channels are presented. The results provide insight into the fluid dynamics within high aspect ratio channels. A water flow test rig constructed out of plexiglass, with an adjustable aspect ratio, was used for these experiments. Results were obtained for a channel geometry with a hydraulic diameter of 10.6 mm (0.417 in.), an aspect ratio of 5.0, and a hydraulic radius to curvature radius ratio of 0.0417. Flow conditions were varied to achieve Reynolds numbers up to 5,100. A new particle imaging velocimetry technique was developed which could resolve velocity information from particles entering and leaving the field of view. Time averaged secondary flow velocity vectors, obtained using this velocimetry technique, are presented for 30 degrees, 60 degrees, and 90 degrees into a 180 degrees bend and at a Reynolds number of 5,100. The secondary flow results suggest the coexistence of both the classical curvature induced vortex pair flow structure and the eddies seen in straight turbulent channel flow.

  10. Heat transfer and pressure drop in rectangular channels with crossing fins (a Review)

    NASA Astrophysics Data System (ADS)

    Sokolov, N. P.; Polishchuk, V. G.; Andreev, K. D.; Rassokhin, V. A.; Zabelin, N. A.

    2015-06-01

    Channels with crossing finning find wide use in the cooling paths of high-temperature gas turbine blade systems. At different times, different institutions carried out experimental investigations of heat transfer and pressure drop in channels with coplanar finning of opposite walls for obtaining semiempirical dependences of Nusselt criteria (dimensionless heat-transfer coefficients) and pressure drop coefficients on the operating Reynolds number and relative geometrical parameters (or their complexes). The shape of experimental channels, the conditions of experiments, and the used variables were selected so that they would be most suited for solving particular practical tasks. Therefore, the results obtained in processing the experimental data have large scatter and limited use. This article considers the results from experimental investigations of different authors. In comparing the results, additional calculations were carried out for bringing the mathematical correlations to the form of dependences from the same variables. Generalization of the results is carried out. In the final analysis, universal correlations are obtained for determining the pressure drop coefficients and Nusselt number values for the flow of working medium in channels with coplanar finning.

  11. Distribution of larval fishes related to potential navigation impacts on the upper Mississippi River, pool 7

    USGS Publications Warehouse

    Holland, L.E.; Sylvester, J.R.

    1983-01-01

    Ichthyoplankton samples were collected twice monthly during spring and summer 1981 from a variety of habitats in Navigation Pool 7 of the upper Mississippi River. Larval-fish distributions in the pool and variations in those distributions were analyzed relative to potential impacts of increased commercial navigation. Although as many as 66 species of adults have been found in the area (33 considered common), only 17 taxa were identified from our collections. In April and May, most larvae were collected in main-channel and main-channel-border areas next to major expanses of shallow backwaters. White bass Morone chrysops, yellow perch Perca flavescens, and crappies Pomoxis spp. were predominant. Numerous catostomids also were taken. In June and July, most larvae were taken in the lower pool. Freshwater drum Aplodinotus grunniens and gizzard shad Dorosoma cepedianum predominated in these samples, which also included many cyprinids and centrarchids. Diel patterns of abundance varied with species and sampling location. Freshwater drums were more abundant near the surface at midnight than during the day. Common carp Cyprinus carpio were most abundant in collections at dusk, whereas all other cyprinids were most abundant at dusk and dawn. Numbers of gizzard shad also increased slightly at dusk. Total numbers of larvae collected were greatest at dusk in main-channel and main-channel-border samples; backwater areas produced the greatest catches at midnight and dawn. Seasonal, spatial, diel, and species-specific variations in larval fish abundances significantly influenced the proportion of the community potentially vulnerable to increased boat traffic through Pool 7.

  12. Femtosecond laser subsurface scleral treatment in cadaver human sclera and evaluation using two-photon and confocal microscopy

    NASA Astrophysics Data System (ADS)

    Sun, Hui; Fan, Zhongwei; Yan, Ying; Lian, Fuqiang; Kurtz, Ron; Juhasz, Tibor

    2016-03-01

    Glaucoma is the second-leading cause of blindness worldwide and is often associated with elevated intraocular pressure (IOP). Partial-thickness drainage channels can be created with femtosecond laser in the translucent sclera for the potential treatment of glaucoma. We demonstrate the creation of partial-thickness subsurface drainage channels with the femtosecond laser in the cadaver human eyeballs and describe the application of two-photon microscopy and confocal microscopy for noninvasive imaging of the femtosecond laser created partial-thickness scleral channels in cadaver human eyes. A femtosecond laser operating at a wavelength of 1700 nm was scanned along a rectangular raster pattern to create the partial thickness subsurface drainage channels in the sclera of cadaver human eyes. Analysis of the dimensions and location of these channels is important in understanding their effects. We describe the application of two-photon microscopy and confocal microscopy for noninvasive imaging of the femtosecond laser created partial-thickness scleral channels in cadaver human eyes. High-resolution images, hundreds of microns deep in the sclera, were obtained to allow determination of the shape and dimension of such partial thickness subsurface scleral channels. Our studies suggest that the confocal and two-photon microscopy can be used to investigate femtosecond-laser created partial-thickness drainage channels in the sclera of cadaver human eyes.

  13. Fluid Flow and Mass Transfer in Micro/Nano-Channels

    NASA Astrophysics Data System (ADS)

    Conlisk, A. T.; McFerran, Jennifer; Hansford, Derek; Zheng, Zhi

    2001-11-01

    In this work the fluid flow and mass transfer due to the presence of an electric field in a rectangular channel is examined. We consider a mixture of water or other neutral solvent and a salt compound such as sodium chloride for which the ionic species are entirely dissociated. Results are produced for the case where the channel height is much greater than the electric double layer(EDL)(microchannel) and for the case where the channel height is of the order or somewhat greater than the width of the EDL(nanochannel). For the electroosmotic flow so induced, the velocity field and the potential are similar. The fluid is assumed to behave as a continuum and the Boltzmann distribution for the mole fractions of the ions emerges from the classical dilute mass transfer equation in the limiting case where the EDL thickness is much less than the channel height. Depending on the relative magnitude of the mole fractions at the walls of the channel, both forward and reversed flow may occur. The volume flow rate is observed to vary linearly with channel height for electrically driven flow in contrast to pressure driven flow which varies as height cubed. This means that power requirements for small channels are much greater for pressure driven flow. Supported by DARPA

  14. Improving flow distribution in influent channels using computational fluid dynamics.

    PubMed

    Park, No-Suk; Yoon, Sukmin; Jeong, Woochang; Lee, Seungjae

    2016-10-01

    Although the flow distribution in an influent channel where the inflow is split into each treatment process in a wastewater treatment plant greatly affects the efficiency of the process, and a weir is the typical structure for the flow distribution, to the authors' knowledge, there is a paucity of research on the flow distribution in an open channel with a weir. In this study, the influent channel of a real-scale wastewater treatment plant was used, installing a suppressed rectangular weir that has a horizontal crest to cross the full channel width. The flow distribution in the influent channel was analyzed using a validated computational fluid dynamics model to investigate (1) the comparison of single-phase and two-phase simulation, (2) the improved procedure of the prototype channel, and (3) the effect of the inflow rate on flow distribution. The results show that two-phase simulation is more reliable due to the description of the free-surface fluctuations. It should first be considered for improving flow distribution to prevent a short-circuit flow, and the difference in the kinetic energy with the inflow rate makes flow distribution trends different. The authors believe that this case study is helpful for improving flow distribution in an influent channel.

  15. Investigation of flood routing by a dynamic wave model in trapezoidal channels

    NASA Astrophysics Data System (ADS)

    Sulistyono, B. A.; Wiryanto, L. H.

    2017-08-01

    The problems of flood wave propagation, in bodies of waters, cause by intense rains or breaking of control structures, represent a great challenge in the mathematical modeling processes. This research concerns about the development and application of a mathematical model based on the Saint Venant's equations, to study the behavior of the propagation of a flood wave in trapezoidal channels. In these equations, the momentum equation transforms to partial differential equation which has two parameters related to cross-sectional area and discharge of the channel. These new formulas have been solved by using an explicit finite difference scheme. In computation procedure, after computing the discharge from the momentum equation, the cross-sectional area will be obtained from the continuity equation for a given point of channel. To evaluate the behavior of the control variables, several scenarios for the main channel as well as for flood waves are considered and different simulations are performed. The simulations demonstrate that for the same bed width, the peak discharge in trapezoidal channel smaller than in rectangular one at a specific distance along the channel length and so, that roughness coefficient and bed slope of the channel play a strong game on the behavior of the flood wave propagation.

  16. Micro-channel filling flow considering surface tension effect

    NASA Astrophysics Data System (ADS)

    Kim, Dong Sung; Lee, Kwang-Cheol; Kwon, Tai Hun; Lee, Seung S.

    2002-05-01

    Understanding filling flow into micro-channels is important in designing micro-injection molding, micro-fluidic devices and an MIMIC (micromolding in capillaries) process. In this paper, we investigated, both experimentally and numerically, 'transient filling' flow into micro-channels, which differs from steady-state completely 'filled' flow in micro-channels. An experimental flow visualization system was devised to facilitate observation of flow characteristics in filling into micro-channels. Three sets of micro-channels of various widths of different thicknesses (20, 30, and 40 μm) were fabricated using SU-8 on the silicon substrate to find a geometric effect with regard to pressure gradient, viscous force and, in particular, surface tension. A numerical analysis system has also been developed taking into account the surface tension effect with a contact angle concept. Experimental observations indicate that surface tension significantly affects the filling flow to such an extent that even a flow blockage phenomenon was observed at channels of small width and thickness. A numerical analysis system also confirms that the flow blockage phenomenon could take place due to the flow hindrance effect of surface tension, which is consistent with experimental observation. For proper numerical simulations, two correction factors have also been proposed to correct the conventional hydraulic radius for the filling flow in rectangular cross-sectioned channels.

  17. Numerical study of mixed convection heat transfer enhancement in a channel with active flow modulation

    NASA Astrophysics Data System (ADS)

    Billah, Md. Mamun; Khan, Md Imran; Rahman, Mohammed Mizanur; Alam, Muntasir; Saha, Sumon; Hasan, Mohammad Nasim

    2017-06-01

    A numerical study of steady two dimensional mixed convention heat transfer phenomena in a rectangular channel with active flow modulation is carried out in this investigation. The flow in the channel is modulated via a rotating cylinder placed at the center of the channel. In this study the top wall of the channel is subjected to an isothermal low temperature while a discrete isoflux heater is positioned on the lower wall. The fluid flow under investigation is assumed to have a Prandtl number of 0.71 while the Reynolds No. and the Grashof No. are varied in wide range for four different situations such as: i) plain channel with no cylinder, ii) channel with stationary cylinder, iii) channel with clockwise rotating cylinder and iv) channel with counter clockwise rotating cylinder. The results obtained in this study are presented in terms of the distribution of streamlines, isotherms in the channel while the heat transfer process from the heat source is evaluated in terms of the local Nusselt number, average Nusselt number. The outcomes of this study also indicate that the results are strongly dependent on the type of configuration and direction of rotation of the cylinder and that the average Nusselt number value rises with an increase in Reynolds and Grashof numbers but the correlation between these parameters at higher values of Reynolds and Grashof numbers becomes weak.

  18. 33 CFR 334.300 - Hampton Roads and Willoughby Bay, Norfolk Naval Base, naval restricted area, Norfolk, Virginia.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Hampton Roads and Willoughby Bay... RESTRICTED AREA REGULATIONS § 334.300 Hampton Roads and Willoughby Bay, Norfolk Naval Base, naval restricted... along the eastern limit of Norfolk Harbor Channel to latitude 36°57′52″ N, longitude 76°20′00″ W; thence...

  19. 33 CFR 334.300 - Hampton Roads and Willoughby Bay, Norfolk Naval Base, naval restricted area, Norfolk, Virginia.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Hampton Roads and Willoughby Bay... RESTRICTED AREA REGULATIONS § 334.300 Hampton Roads and Willoughby Bay, Norfolk Naval Base, naval restricted... along the eastern limit of Norfolk Harbor Channel to latitude 36°57′52″ N, longitude 76°20′00″ W; thence...

  20. 33 CFR 334.300 - Hampton Roads and Willoughby Bay, Norfolk Naval Base, naval restricted area, Norfolk, Virginia.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Hampton Roads and Willoughby Bay... RESTRICTED AREA REGULATIONS § 334.300 Hampton Roads and Willoughby Bay, Norfolk Naval Base, naval restricted... along the eastern limit of Norfolk Harbor Channel to latitude 36°57′52″ N, longitude 76°20′00″ W; thence...

  1. Assessing Impacts of Navigation Dredging on Atlantic Sturgeon (Acipenser oxyrinchus)

    DTIC Science & Technology

    2014-11-01

    fishes and insect larvae (Smith 1985, Dadswell 2006). Shallow water shoals located adjacent to both sides of the Federal navigation channel, provide a...incision was closed using sterile resorbitive suture material with four to five simple interrupted stitches. An iodine disinfectant was applied to the...1976). Assessment of techniques used to quantify salmon smolt entrainment by a hydraulic suction hopper dredge in the Fraser River estuary. Environment

  2. Advancing Underwater Acoustic Communication for Autonomous Distributed Networks via Sparse Channel Sensing, Coding, and Navigation Support

    DTIC Science & Technology

    2013-09-30

    underwater acoustic communication technologies for autonomous distributed underwater networks, through innovative signal processing, coding, and navigation...in real enviroments , an offshore testbed has been developed to conduct field experimetns. The testbed consists of four nodes and has been deployed...Leadership by the Connecticut Technology Council. Dr. Zhaohui Wang joined the faculty of the Department of Electrical and Computer Engineering at

  3. Numerical investigation on forced convection in rectangular cross section micro-channels with nanofluids

    NASA Astrophysics Data System (ADS)

    Buonomo, B.; Cirillo, L.; Manca, O.; Nardini, S.; Tamburrino, S.

    2017-01-01

    In this paper a numerical investigation on laminar forced convection flow of a water-Al2O3 nanofluid in a rectangular microchannel is accomplished. A constant and uniform heat flux on the external surfaces has been applied and a single-phase model approach has been employed. The analysis has been performed in steady state regime for particle size in nanofluids equal to 38 nm. The CFD commercial code Fluent has been employed in order to solve the 3-D numerical model. The geometrical configuration under consideration consists in a duct with a rectangular shaped crossing area. A steady laminar flow and different nanoparticle volume fractions have been considered. The base fluid is water and nanoparticles are made up of alumina (Al2O3). The length the edge and height of the duct are 0.030 m, 1.7 x10-7 and 1.1 x10-7 m, respectively. Results are presented in terms of temperature and velocity distributions, surface shear stress and heat transfer convective coefficient, Nusselt number and required pumping power profiles. Comparison with results related to the fluid dynamic and thermal behaviors are carried out in order to evaluate the enhancement due to the presence of nanoparticles in terms of volumetric concentration.

  4. Theoretical modeling of electroosmotic flow in soft microchannels: A variational approach applied to the rectangular geometry

    NASA Astrophysics Data System (ADS)

    Sadeghi, Arman

    2018-03-01

    Modeling of fluid flow in polyelectrolyte layer (PEL)-grafted microchannels is challenging due to their two-layer nature. Hence, the pertinent studies are limited only to circular and slit geometries for which matching the solutions for inside and outside the PEL is simple. In this paper, a simple variational-based approach is presented for the modeling of fully developed electroosmotic flow in PEL-grafted microchannels by which the whole fluidic area is considered as a single porous medium of variable properties. The model is capable of being applied to microchannels of a complex cross-sectional area. As an application of the method, it is applied to a rectangular microchannel of uniform PEL properties. It is shown that modeling a rectangular channel as a slit may lead to considerable overestimation of the mean velocity especially when both the PEL and electric double layer (EDL) are thick. It is also demonstrated that the mean velocity is an increasing function of the fixed charge density and PEL thickness and a decreasing function of the EDL thickness and PEL friction coefficient. The influence of the PEL thickness on the mean velocity, however, vanishes when both the PEL thickness and friction coefficient are sufficiently high.

  5. Application of the Streamflow Prediction Tool to Estimate Sediment Dredging Volumes in Texas Coastal Waterways

    NASA Astrophysics Data System (ADS)

    Yeates, E.; Dreaper, G.; Afshari, S.; Tavakoly, A. A.

    2017-12-01

    Over the past six fiscal years, the United States Army Corps of Engineers (USACE) has contracted an average of about a billion dollars per year for navigation channel dredging. To execute these funds effectively, USACE Districts must determine which navigation channels need to be dredged in a given year. Improving this prioritization process results in more efficient waterway maintenance. This study uses the Streamflow Prediction Tool, a runoff routing model based on global weather forecast ensembles, to estimate dredged volumes. This study establishes regional linear relationships between cumulative flow and dredged volumes over a long-term simulation covering 30 years (1985-2015), using drainage area and shoaling parameters. The study framework integrates the National Hydrography Dataset (NHDPlus Dataset) with parameters from the Corps Shoaling Analysis Tool (CSAT) and dredging record data from USACE District records. Results in the test cases of the Houston Ship Channel and the Sabine and Port Arthur Harbor waterways in Texas indicate positive correlation between the simulated streamflows and actual dredging records.

  6. Frequency bandwidth limitation of external pulse electric fields in cylindrical micro-channel electrophoresis with analyte velocity modulation.

    PubMed

    Wang, Shau-Chun; Chen, Hsiao-Ping; Lee, Chia-Yu; Yeo, Leslie Y

    2005-04-15

    In capillary electrophoresis, effective optical signal quality improvement is obtained when high frequency (>100 Hz) external pulse fields modulate analyte velocities with synchronous lock-in detection. However, the pulse frequency is constrained under a critical value corresponding to the time required for the bulk viscous flow, which arises due to viscous momentum diffusion from the electro-osmotic slip in the Debye layer, to reach steady-state. By solving the momentum diffusion equation for transient bulk flow in the micro-channel, we show that this set-in time to steady-state and hence, the upper limit for the pulse frequency is dependent on the characteristic diffusion length scale and therefore the channel geometry; for cylindrical capillaries, the set-in time is approximately one half of that for rectangular slot channels. From our estimation of the set-in time and hence the upper frequency modulation limit, we propose that the half width of planar channels does not exceed 100 microm and that the radii of cylindrical channels be limited to 140 microm such that there is a finite working bandwidth range above 100 Hz and below the upper limit in order for flicker noise to be effectively suppressed.

  7. Effect of Multivalent Ions on Electroosmotic Flow in Micro- and Nano-channels

    NASA Astrophysics Data System (ADS)

    Zheng, Zhi; Conlisk, A. Terrence

    2002-11-01

    In this work, the effect of multivalent ions on electroosmotic flow is investigated. Applications in biomedical engineering are numerous, including design of drug delivery systems, rapid molecular analysis and lab-on-a-chip. We specifically consider incorporating Ca^2+ and HPO4^2- and other monovalent ions, such as K^+ and H2PO4^-, into an aqueous NaCl solution. All previous work has been for the case where the mixture contains a pair of ionic species of equal valence. Electrochemical equilibrium considerations are used in determining the boundary conditions. The results can be applied to rectangular channels for which the height is on the nanometer scale up to the micrometer scale. The classical electroosmotic velocity profile is obtained at larger channel heights for fixed electrolyte concentration where an analytic solution for the velocity, potential and mole fractions may be obtained. The theory is valid for an arbitrary number of ionic species.

  8. Viscous near-wall flow in a wake of circular cylinder at moderate Reynolds numbers

    NASA Astrophysics Data System (ADS)

    Okhotnikov, D. I.; Molochnikov, V. M.; Mazo, A. B.; Malyukov, A. V.; Goltsman, A. E.; Saushin, I. I.

    2017-11-01

    Here we present the results of experimental investigation of a cross flow around a circular cylinder mounted near the wall of a channel with rectangular cross section. The experiments were carried out in the range of Reynolds numbers corresponding to the transition to turbulence in a wake of the cylinder. Flow visualization and SIV-measurements of instantaneous velocity fields were carried out. Evolution of the flow pattern behind the cylinder and formation of the regular vortex structures were analyzed. It is shown that in the case of flow around the cylinder, there is no spiral motion of fluid from the side walls of the channel towards its symmetry plane, typical of the flow around a spanwise rib located on the channel wall. The laminar-turbulent transition in the wake of the cylinder is caused by the shear layer instability.

  9. Influence of internal channel geometry of gas turbine blade on flow structure and heat transfer

    NASA Astrophysics Data System (ADS)

    Szwaba, Ryszard; Kaczynski, Piotr; Telega, Janusz; Doerffer, Piotr

    2017-12-01

    This paper presents the study of the influence of channel geometry on the flow structure and heat transfer, and also their correlations on all the walls of a radial cooling passage model of a gas turbine blade. The investigations focus on the heat transfer and aerodynamic measurements in the channel, which is an accurate representation of the configuration used in aeroengines. Correlations for the heat transfer coefficient and the pressure drop used in the design of internal cooling passages are often developed from simplified models. It is important to note that real engine passages do not have perfect rectangular cross sections, but include a corner fillets, ribs with fillet radii and a special orientation. Therefore, this work provides detailed fluid flow and heat transfer data for a model of radial cooling geometry which has very realistic features.

  10. Physically Modeling Stream Channel Adjustment to Woody Riparian Vegetation

    NASA Astrophysics Data System (ADS)

    Bennett, S. J.; Alonso, C. V.

    2003-12-01

    Stream restoration designs often use vegetation to promote bank and channel stability, to facilitate point-bar development, and to encourage natural colonization of riparian species. Here we examine the adjustment of an alluvial channel to in-stream and riparian vegetation using a distorted Froude-scale flume model with a movable boundary. A decimeter-scale trapezoidal channel comprised of 0.8-mm diameter sand was systematically vegetated with emergent, rigid dowels (3-mm in diameter) in rectangular and hemispherical patterns with varying vegetation densities while conserving the shape of the zone and the geometry of the vegetal patterns. Alternate sides of the channel were vegetated at the prescribed spacing of equilibrium alternate bars, ca. 5 to 7 times the channel width. Using flow conditions just below the threshold of sediment motion, flow obstruction, deflection, and acceleration caused bed erosion, bank failure, and morphologic channel adjustments that were wholly attributable to the managed plantings. As vegetation density increased, the magnitude and rate of scaled channel adjustment increased, which included increased channel widths, bankline steepening and meandering, and thalweg meandering. As the modeled channel began to meander, the stream bed aggraded and flow depth decreased markedly, creating a continuously connected, inter-reach complex of mid-channel bars. This study demonstrates the utility of using managed vegetations in stream corridor design and meander development, and it provides the practitioner with guidance on the magnitude of channel adjustment as it relates to vegetation density, shape, and spacing.

  11. Three dimensional model evaluation of physical alterations of the Caloosahatchee River and Estuary: Impact on salt transport

    NASA Astrophysics Data System (ADS)

    Sun, Detong; Wan, Yongshan; Qiu, Chelsea

    2016-05-01

    Numerical hydrodynamic modeling provides quantitative understanding of how physical alterations of an estuary may alter the waterbody hydrodynamics and the rate of mixing with the ocean. In this study, a three dimensional hydrodynamic model (CH3D) was used to compare simulated salinities between the existing condition and five historical cases representing varying physical alterations of the Caloosahatchee Estuary involving (1) removal of the headwater structure (S-79); (2) removal of the downstream causeway to Sanibel Island; (3) backfilling an oyster bar near the estuary month; (4) refilling the navigation channel; and (5) the pre-development bathymetric condition. The results suggested that some alterations including the Sanibel Causeway, backfilling the oyster bar and the S-79 structure may have some local effects but did not change estuarine salinity structure significantly. Refilling the navigation channel had a more profound effect, resulting in a dry season salinity reduction of about 5 when compared with the existing condition. The reduced salt transport was more pronounced with the pre-development bathymetry because the estuary as a whole was much shallower than today. The significant system-wide increase in salt transport caused by the historic dredging of the navigation channel in the Caloosahatchee Estuary has significant implications in the development of attainable environmental flow targets for protecting the estuarine ecosystem.

  12. A Regional Waterway Management System for Balancing Recreational Boating and Resource Protection

    NASA Astrophysics Data System (ADS)

    Swett, Robert A.; Listowski, Charles; Fry, Douglas; Boutelle, Stephen; Fann, David

    2009-06-01

    Florida’s coasts have been transformed over the past three decades as population growth and unprecedented demand for individual shore access to bays and estuaries led to the creation of residential canal developments. Thousands of miles of channels and basins were dredged as a by-product of this urbanization process. The navigable waterways that resulted are now being stressed by increasing boat traffic and canal-side activities. Recognizing their common goal to preserve the recreational and ecological value of southwest Florida waterways, the Florida Department of Environmental Protection, the four-county West Coast Inland Navigation District, and the University of Florida Sea Grant College Program signed a Memorandum of Agreement. The signatories agreed to develop a science-based Regional Waterway Management System (RWMS), which is a new approach to waterway planning and permitting based on carefully mapped channel depths, a census of actual boat populations, and the spatial extent of natural resources. The RWMS provides a comprehensive, regional overview of channel conditions and the geographic distribution and severity of existing impediments to safe navigation and resource protection. RWMS information and analyses result in regional-scale permitting to accommodate water-dependent uses while minimizing environmental impacts and reducing public expenditures. Compared with traditional approaches to waterway management, the science-based RWMS is relatively unbiased, objective, transparent, ecologically sound, and fiscally prudent.

  13. 78 FR 17094 - Safety Zone; 2013 Naval Air Station Key West Air Spectacular, Boca Chica Channel; Boca Chica, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-20

    ...-AA00 Safety Zone; 2013 Naval Air Station Key West Air Spectacular, Boca Chica Channel; Boca Chica, FL... Air Station Key West Air Spectacular. The safety zone is necessary to provide for the safety of life on navigable waters during the air show and air show practices. Persons and vessels are prohibited...

  14. Is there a geometric module for spatial orientation? Insights from a rodent navigation model.

    PubMed

    Sheynikhovich, Denis; Chavarriaga, Ricardo; Strösslin, Thomas; Arleo, Angelo; Gerstner, Wulfram

    2009-07-01

    Modern psychological theories of spatial cognition postulate the existence of a geometric module for reorientation. This concept is derived from experimental data showing that in rectangular arenas with distinct landmarks in the corners, disoriented rats often make diagonal errors, suggesting their preference for the geometric (arena shape) over the nongeometric (landmarks) cues. Moreover, sensitivity of hippocampal cell firing to changes in the environment layout was taken in support of the geometric module hypothesis. Using a computational model of rat navigation, the authors proposed and tested the alternative hypothesis that the influence of spatial geometry on both behavioral and neuronal levels can be explained by the properties of visual features that constitute local views of the environment. Their modeling results suggest that the pattern of diagonal errors observed in reorientation tasks can be understood by the analysis of sensory information processing that underlies the navigation strategy employed to solve the task. In particular, 2 navigation strategies were considered: (a) a place-based locale strategy that relies on a model of grid and place cells and (b) a stimulus-response taxon strategy that involves direct association of local views with action choices. The authors showed that the application of the 2 strategies in the reorientation tasks results in different patterns of diagonal errors, consistent with behavioral data. These results argue against the geometric module hypothesis by providing a simpler and biologically more plausible explanation for the related experimental data. Moreover, the same model also describes behavioral results in different types of water-maze tasks. Copyright (c) 2009 APA, all rights reserved.

  15. [Development of a Surgical Navigation System with Beam Split and Fusion of the Visible and Near-Infrared Fluorescence].

    PubMed

    Yang, Xiaofeng; Wu, Wei; Wang, Guoan

    2015-04-01

    This paper presents a surgical optical navigation system with non-invasive, real-time, and positioning characteristics for open surgical procedure. The design was based on the principle of near-infrared fluorescence molecular imaging. The in vivo fluorescence excitation technology, multi-channel spectral camera technology and image fusion software technology were used. Visible and near-infrared light ring LED excitation source, multi-channel band pass filters, spectral camera 2 CCD optical sensor technology and computer systems were integrated, and, as a result, a new surgical optical navigation system was successfully developed. When the near-infrared fluorescence was injected, the system could display anatomical images of the tissue surface and near-infrared fluorescent functional images of surgical field simultaneously. The system can identify the lymphatic vessels, lymph node, tumor edge which doctor cannot find out with naked eye intra-operatively. Our research will guide effectively the surgeon to remove the tumor tissue to improve significantly the success rate of surgery. The technologies have obtained a national patent, with patent No. ZI. 2011 1 0292374. 1.

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

    DTIC Science & Technology

    2002-08-23

    can be completed in 2 to 4 hours. Currently accepted tests using commercial test kits based on immunochemical techniques offer results in 22 to 24...tagging is imperfect, leading to a background of non-specific surface and molecular binding limiting the signal. The use of a reporter fluorochrome can ...Waveguide Patterning: Surface flow channels: The rectangular cuvettes (as shown in Section II, Figure 4-3) can be etched using standard techniques. The

  17. Transient Magnetohydrodynamic Liquid-Metal Flows in a Rectangular Channel with a Moving Conducting Wall

    DTIC Science & Technology

    1988-05-01

    use of liquid metals for current collectors in homopolar motors and generators has led to the design of machines of superior performance. The steady...In some applications of homopolar generators it becomes necessary not only to start and stop the machines but also to operate them under oscillating...conditions. This could be the case in an application where a homopolar generator behaves as an extremely high energy capacitor. Therefore, one is

  18. Heat Transfer Enhancement due to Bubble Pumping in FC-72 Near the Saturation Temperature

    DTIC Science & Technology

    1991-03-01

    boiling, (2) reducing wall superheat during nucleate boiling and (3) enhancing critical heat flux ( Mudawar , 1990) . Since the heat transfer potential of...flux from a simulated electronic chip attached to the wall of a vertical rectangular channel was determined by Mudawar and Madox (1988). They concluded...Surface Boiling," Industrial and Engineering Chemistry, vol. 41, No. 9, 1949. Mudawar , I., and D.E. Maddox, Critical Heat Flux in Subcooled Flow Boiling

  19. REDISTRIBUTOR FOR LIQUID-LIQUID EXTRACTION COLUMNS

    DOEpatents

    Bradley, J.G.

    1957-10-29

    An improved baffle plate construction to intimately mix immiscible liquid solvents for solvent extraction processes in a liquid-liquid pulse column is described. To prevent the light and heavy liquids from forming separate continuous homogeneous vertical channels through sections of the column, a baffle having radially placed rectangular louvers with deflection plates opening upon alternate sides of the baffle is placed in the column, normal to the axis. This improvement substantially completely reduces strippiig losses due to poor mixing.

  20. On the Induced Flow of an Electrically Conducting Liquid in a Rectangular Duct by Electric and Magnetic Fields of Finite Extent

    NASA Technical Reports Server (NTRS)

    Rossow, Vernon J.; Jones, William Prichard; Huerta, Robert H.

    1961-01-01

    Reported here are the results of a systematic study of a model of the direct-current electromagnetic pump. Of particular interest is the motion imparted to the electrically conducting fluid in the rectangular duct by the body forces that result from applied electric and magnetic fields. The purpose of the investigation is to associate the observed fluid motion with the characteristics of the electric and magnetic fields which cause them. The experiments were carried out with electromagnetic fields that moved a stream of copper sulphate solution through a clear plastic channel. Ink filaments injected into the stream ahead of the region where the fields were applied identify the motion of the fluid elements as they passed through the test channel. Several magnetic field configurations were employed with a two-dimensional electric current distribution in order to study and identify the magnitude of some of the effects on the fluid motion brought about by nonuniformities in the electromagnetic fields. A theoretical analysis was used to guide and evaluate the identification of the several fluid motions observed. The agreement of the experimental data with the theoretical predictions is satisfactory. It is found that sizable variations in the velocity profile and pressure head of the output stream are produced by the shape of the electric and magnetic fields.

  1. Spectral Optical Readout of Rectangular–Miniature Hollow Glass Tubing for Refractive Index Sensing

    PubMed Central

    Rigamonti, Giulia; Bello, Valentina

    2018-01-01

    For answering the growing demand of innovative micro-fluidic devices able to measure the refractive index of samples in extremely low volumes, this paper presents an overview of the performances of a micro-opto-fluidic sensing platform that employs rectangular, miniature hollow glass tubings. The operating principle is described by showing the analytical model of the tubing, obtained as superposition of different optical cavities, and the optical readout method based on spectral reflectivity detection. We have analyzed, in particular, the theoretical and experimental optical features of rectangular tubings with asymmetrical geometry, thus with channel depth larger than the thickness of the glass walls, though all of them in the range of a few tens of micrometers. The origins of the complex line-shape of the spectral response in reflection, due to the different cavities formed by the tubing flat walls and channel, have been investigated using a Fourier transform analysis. The implemented instrumental configuration, based on standard telecom fiberoptic components and a semiconductor broadband optical source emitting in the near infrared wavelength region centered at 1.55 µm, has allowed acquisition of reflectivity spectra for experimental verification of the expected theoretical behavior. We have achieved detection of refractive index variations related to the change of concentration of glucose-water solutions flowing through the tubing by monitoring the spectral shift of the optical resonances. PMID:29462907

  2. Human Effects on Varna-Beloslav Lake Complex and Detection of Long-Term Changes

    NASA Astrophysics Data System (ADS)

    Palazov, Atanas; Stanchev, Hristo; Stancheva, Margarita

    2013-04-01

    There are several larger lakes at the 412 km long Bulgarian Black Sea coastline, as each distinguishes with a specific hydrological regime and parameters. The deepest and the largest is the Varna Lake, located west from the Bay of Varna at the North Bulgarian coast. The lake is a firth formation at the river valley under a rising sea level during the Holocene, when it was divided from the sea by a large sandy spit. In 1900s with construction of Varna Port a navigational channel between Varna Lake and the sea was built, while in 1920s it was artificially connected to the inland Beloslav Lake by other navigational channel. Since the beginning of the past century the both lakes have been subject of many direct human impacts, such as: digging of three navigational channels; situating a number of ports with different functions; constantly performed dredging activities etc. The aim of this study was to trace the long-term changes to the lakes of Varna and Beloslav mostly related to human activities over a 100-year period. Two types of data were used: historical topographic map from 1910 in scale 1:200 000 and nautical maps in scale 1:10 000 from 1994. The data were processed and analysed with support of GIS and modelling in order to quantify the changes of areas and volumes of the lakes, as well as of the navigational channel between them. The findings from the study clearly reveal significant alterations of the two lakes that have been caused by increased anthropogenic impacts over the whole past century. Irreversible changes and modifications of the lakes features and coastal section around, as well as alterations of the areas and hydrological regime of the whole lake system were identified. In order to evaluate the anthropogenic impacts a coastline segmentation of the study area was performed as the lengths of natural and armoured coasts were determined. This in turn allowed finding the extent of technogenous occupation of the coast: 11107 m or about 24% from the total 46112 m long lakes coastline were armoured. Adding also two navigational channels having a total length of 8500 m, then the length of the technogenous coast has reached up to 42 %. In relation with required maintenance of the safe shipping depth and following permanent dredging works, it is suggests the examined Varna-Beloslav Lake system would experience continuative impacts and negative effects. At present, a new project for replacement of the Varna Port East to the northernmost part of the Varna Lake has been operating and this would suppose additional dredging activities leading to new changes of the coastline and bottom features of both lakes.

  3. A Consistent EPIC Visible Channel Calibration Using VIIRS and MODIS as a Reference.

    NASA Astrophysics Data System (ADS)

    Haney, C.; Doelling, D. R.; Minnis, P.; Bhatt, R.; Scarino, B. R.; Gopalan, A.

    2017-12-01

    The Earth Polychromatic Imaging Camera (EPIC) aboard the Deep Space Climate Observatory (DSCOVR) satellite constantly images the sunlit disk of Earth from the Lagrange-1 (L1) point in 10 spectral channels spanning the UV, VIS, and NIR spectrums. Recently, the DSCOVR EPIC team has publicly released version 2 dataset, which has implemented improved navigation, stray-light correction, and flat-fielding of the CCD array. The EPIC 2-year data record must be well-calibrated for consistent cloud, aerosol, trace gas, land use and other retrievals. Because EPIC lacks onboard calibrators, the observations made by EPIC channels must be calibrated vicariously using the coincident measurements from radiometrically stable instruments that have onboard calibration systems. MODIS and VIIRS are best-suited instruments for this task as they contain similar spectral bands that are well-calibrated onboard using solar diffusers and lunar tracking. We have previously calibrated the EPIC version 1 dataset by using EPIC and VIIRS angularly matched radiance pairs over both all-sky ocean and deep convective clouds (DCC). We noted that the EPIC image required navigations adjustments, and that the EPIC stray-light correction provided an offset term closer to zero based on the linear regression of the EPIC and VIIRS ray-matched radiance pairs. We will evaluate the EPIC version 2 navigation and stray-light improvements using the same techniques. In addition, we will monitor the EPIC channel calibration over the two years for any temporal degradation or anomalous behavior. These two calibration methods will be further validated using desert and DCC invariant Earth targets. The radiometric characterization of the selected invariant targets is performed using multiple years of MODIS and VIIRS measurements. Results of these studies will be shown at the conference.

  4. A Consistent EPIC Visible Channel Calibration using VIIRS and MODIS as a Reference

    NASA Technical Reports Server (NTRS)

    Haney, C. O.; Doelling, D. R.; Minnis, P.; Bhatt, R.; Scarino, B. R.; Gopalan, A.

    2017-01-01

    The Earth Polychromatic Imaging Camera (EPIC) aboard the Deep Space Climate Observatory (DSCOVR) satellite constantly images the sunlit disk of Earth from the Lagrange-1 (L1) point in 10 spectral channels spanning the UV, VIS, and NIR spectrums. Recently, the DSCOVR EPIC team has publicly released version 2 dataset, which has implemented improved navigation, stray-light correction, and flat-fielding of the CCD array. The EPIC 2-year data record must be well-calibrated for consistent cloud, aerosol, trace gas, land use and other retrievals. Because EPIC lacks onboard calibrators, the observations made by EPIC channels must be calibrated vicariously using the coincident measurements from radiometrically stable instruments that have onboard calibration systems. MODIS and VIIRS are best-suited instruments for this task as they contain similar spectral bands that are well-calibrated onboard using solar diffusers and lunar tracking. We have previously calibrated the EPIC version 1 dataset by using EPIC and VIIRS angularly matched radiance pairs over both all-sky ocean and deep convective clouds (DCC). We noted that the EPIC image required navigations adjustments, and that the EPIC stray-light correction provided an offset term closer to zero based on the linear regression of the EPIC and VIIRS ray-matched radiance pairs. We will evaluate the EPIC version 2 navigation and stray-light improvements using the same techniques. In addition, we will monitor the EPIC channel calibration over the two years for any temporal degradation or anomalous behavior. These two calibration methods will be further validated using desert and DCC invariant Earth targets. The radiometric characterization of the selected invariant targets is performed using multiple years of MODIS and VIIRS measurements. Results of these studies will be shown at the conference.

  5. Historical Sediment Sources and Delivery on the Lower Mississippi River

    NASA Astrophysics Data System (ADS)

    Dahl, T. A.; Biedenharn, D. S.; Little, C. D.

    2015-12-01

    The development of the Lower Mississippi River (LMR) and its floodplain for navigation and flood control has been ongoing since the 18th century, with the most concerted efforts occurring as a result of the Flood Control Act (FCA) of 1928 following the Great Flood of 1927. The Mississippi River and Tributaries (MR&T) Project that was spawned from the FCA of 1928 has produced a massive, comprehensive system for flood control and channel stabilization that includes levees, channel improvements, and floodways, as well as tributary reservoirs and other basin improvements. Additionally, the development of the river for safe and dependable navigation has generated a substantial engineering effort involving river training structures, meander cutoffs, and dredging. The historical, and present-day morphology of the LMR reflects an integration of all these engineering interventions (and the process-responses they have triggered in the fluvial system), combined with natural drivers of channel change and evolution, including floods and droughts, hurricanes, neotectonic activity, geologic outcrops, climate change, and relative sea-level rise. In response to the complex requirements in navigation, flood risk reduction, and environmental restoration, all with multiple stakeholders, the U.S. Army Corps of Engineers created the Mississippi River Geomorphology & Potamology (MRG&P) Program. The goals of the MRG&P are to advance the knowledge of the geomorphology of the LMR and to transfer this technology to improve and sustain long-term management of the system. The results presented herein come from several MRG&P studies. The historical river morphology, and particularly the sources and delivery of sediments have changed dramatically over the past two centuries. In this presentation, the changes in sediment sources, and the manner in which this sediment is delivered through the channel system from the early 1800s to present-day is described.

  6. Forcing functions governing salt transport processes in coastal navigation canals and connectivity to surrounding marshes in South Louisiana using Houma Navigation Canal as a surrogate

    USGS Publications Warehouse

    Snedden, Gregg

    2014-01-01

    Understanding how circulation and mixing processes in coastal navigation canals influence the exchange of salt between marshes and coastal ocean, and how those processes are modulated by external physical processes, is critical to anticipating effects of future actions and circumstance. Examples of such circumstances include deepening the channel, placement of locks in the channel, changes in freshwater discharge down the channel, changes in outer continental shelf (OCS) vessel traffic volume, and sea level rise. The study builds on previous BOEM-funded studies by investigating salt flux variability through the Houma Navigation Canal (HNC). It examines how external physical factors, such as buoyancy forcing and mixing from tidal stirring and OCS vessel wakes, influence dispersive and advective fluxes through the HNC and the impact of this salt flux on salinity in nearby marshes. This study quantifies salt transport processes and salinity variability in the HNC and surrounding Terrebonne marshes. Data collected for this study include time-series data of salinity and velocity in the HNC, monthly salinity-depth profiles along the length of the channel, hourly vertical profiles of velocity and salinity over multiple tidal cycles, and salinity time series data at three locations in the surrounding marshes along a transect of increasing distance from the HNC. Two modes of vertical current structure were identified. The first mode, making up 90% of the total flow field variability, strongly resembled a barotropic current structure and was coherent with alongshelf wind stress over the coastal Gulf of Mexico. The second mode was indicative of gravitational circulation and was linked to variability in tidal stirring and the longitudinal salinity gradients along the channel’s length. Diffusive process were dominant drivers of upestuary salt transport, except during periods of minimal tidal stirring when gravitational circulation became more important. Salinity in the surrounding marshes was much more responsive to salinity variations in the HNC than it was to variations in the lower Terrebonne marshes, suggesting that the HNC is the primary conduit for saltwater intrusion to the middle Terrebonne marshes. Finally, salt transport to the middle Terrebonne marshes directly associated with vessel wakes was negligible.

  7. Alterations in macroinvertebrate spatial patterns in coastal lagoons: Óbidos (NW coast of Portugal) 1984 versus 2002

    NASA Astrophysics Data System (ADS)

    Rodrigues, Ana Maria; Quintino, Victor; Pereira, Fábio; Freitas, Rosa

    2012-09-01

    The macroinvertebrate spatial distribution patterns in the Lagoon of Óbidos were studied in 1984 and revisited in 2002. The overall surficial sediments and benthic community patterns show consistent similarities in the two sampling periods, but also important differences. The lagoon is relatively shallow, with about 1/3 of the area covered with extensive intertidal sand banks. These are interrupted by a navigation channel bordering the northern margin (1984) and, following dredging operations, a new navigation channel was opened along the southern margin (2002). The sediments in the navigation channels were coarser and with less percentage of fines in 2002 than in 1984. Arthropods dominated the species richness and abundance in 1984, but were much less important in 2002, when the community was dominated by molluscs and annelids, both in species numbers as well as in abundance. In 1984, the structure of the macrofauna communities closely followed a general model proposed for Atlantic and Mediterranean lagoons, with the marine, the transition and the lagoon communities occupying very well defined areas. This gradient was in accordance with an increase in the fines and organic matter content directed inwards allowing for the coexistence of several characteristic lagoon species with others characteristic of organic enriched sediments. In 2002 this spatial pattern is still recognized but the marine and the transition communities are spatially mixed, occupying both the entrance region and the navigation channels, whereas the characteristic lagoon community identified in 1984 was only recognized in a group of sites located along the southern margin in 2002. Several species show very important changes in their distribution extent in the lagoon system. These changes essentially show a generalized inward expansion of the distribution range of the marine species, in agreement with a larger influence of marine conditions toward the inner areas of the lagoon. This study shows how sensitive lagoon systems can be to the regime of water exchange rate with the ocean being possible to induce more or less marine conditions to the system as a response to the flow and exchange rate of water through the communication inlet following dredging interventions.

  8. Image navigation and registration performance assessment tool set for the GOES-R Advanced Baseline Imager and Geostationary Lightning Mapper

    NASA Astrophysics Data System (ADS)

    De Luccia, Frank J.; Houchin, Scott; Porter, Brian C.; Graybill, Justin; Haas, Evan; Johnson, Patrick D.; Isaacson, Peter J.; Reth, Alan D.

    2016-05-01

    The GOES-R Flight Project has developed an Image Navigation and Registration (INR) Performance Assessment Tool Set (IPATS) for measuring Advanced Baseline Imager (ABI) and Geostationary Lightning Mapper (GLM) INR performance metrics in the post-launch period for performance evaluation and long term monitoring. For ABI, these metrics are the 3-sigma errors in navigation (NAV), channel-to-channel registration (CCR), frame-to-frame registration (FFR), swath-to-swath registration (SSR), and within frame registration (WIFR) for the Level 1B image products. For GLM, the single metric of interest is the 3-sigma error in the navigation of background images (GLM NAV) used by the system to navigate lightning strikes. 3-sigma errors are estimates of the 99. 73rd percentile of the errors accumulated over a 24 hour data collection period. IPATS utilizes a modular algorithmic design to allow user selection of data processing sequences optimized for generation of each INR metric. This novel modular approach minimizes duplication of common processing elements, thereby maximizing code efficiency and speed. Fast processing is essential given the large number of sub-image registrations required to generate INR metrics for the many images produced over a 24 hour evaluation period. Another aspect of the IPATS design that vastly reduces execution time is the off-line propagation of Landsat based truth images to the fixed grid coordinates system for each of the three GOES-R satellite locations, operational East and West and initial checkout locations. This paper describes the algorithmic design and implementation of IPATS and provides preliminary test results.

  9. Image Navigation and Registration (INR) Performance Assessment Tool Set (IPATS) for the GOES-R Advanced Baseline Imager and Geostationary Lightning Mapper

    NASA Technical Reports Server (NTRS)

    DeLuccia, Frank J.; Houchin, Scott; Porter, Brian C.; Graybill, Justin; Haas, Evan; Johnson, Patrick D.; Isaacson, Peter J.; Reth, Alan D.

    2016-01-01

    The GOES-R Flight Project has developed an Image Navigation and Registration (INR) Performance Assessment Tool Set (IPATS) for measuring Advanced Baseline Imager (ABI) and Geostationary Lightning Mapper (GLM) INR performance metrics in the post-launch period for performance evaluation and long term monitoring. For ABI, these metrics are the 3-sigma errors in navigation (NAV), channel-to-channel registration (CCR), frame-to-frame registration (FFR), swath-to-swath registration (SSR), and within frame registration (WIFR) for the Level 1B image products. For GLM, the single metric of interest is the 3-sigma error in the navigation of background images (GLM NAV) used by the system to navigate lightning strikes. 3-sigma errors are estimates of the 99.73rd percentile of the errors accumulated over a 24 hour data collection period. IPATS utilizes a modular algorithmic design to allow user selection of data processing sequences optimized for generation of each INR metric. This novel modular approach minimizes duplication of common processing elements, thereby maximizing code efficiency and speed. Fast processing is essential given the large number of sub-image registrations required to generate INR metrics for the many images produced over a 24 hour evaluation period. Another aspect of the IPATS design that vastly reduces execution time is the off-line propagation of Landsat based truth images to the fixed grid coordinates system for each of the three GOES-R satellite locations, operational East and West and initial checkout locations. This paper describes the algorithmic design and implementation of IPATS and provides preliminary test results.

  10. Image Navigation and Registration Performance Assessment Tool Set for the GOES-R Advanced Baseline Imager and Geostationary Lightning Mapper

    NASA Technical Reports Server (NTRS)

    De Luccia, Frank J.; Houchin, Scott; Porter, Brian C.; Graybill, Justin; Haas, Evan; Johnson, Patrick D.; Isaacson, Peter J.; Reth, Alan D.

    2016-01-01

    The GOES-R Flight Project has developed an Image Navigation and Registration (INR) Performance Assessment Tool Set (IPATS) for measuring Advanced Baseline Imager (ABI) and Geostationary Lightning Mapper (GLM) INR performance metrics in the post-launch period for performance evaluation and long term monitoring. For ABI, these metrics are the 3-sigma errors in navigation (NAV), channel-to-channel registration (CCR), frame-to-frame registration (FFR), swath-to-swath registration (SSR), and within frame registration (WIFR) for the Level 1B image products. For GLM, the single metric of interest is the 3-sigma error in the navigation of background images (GLM NAV) used by the system to navigate lightning strikes. 3-sigma errors are estimates of the 99.73rd percentile of the errors accumulated over a 24-hour data collection period. IPATS utilizes a modular algorithmic design to allow user selection of data processing sequences optimized for generation of each INR metric. This novel modular approach minimizes duplication of common processing elements, thereby maximizing code efficiency and speed. Fast processing is essential given the large number of sub-image registrations required to generate INR metrics for the many images produced over a 24-hour evaluation period. Another aspect of the IPATS design that vastly reduces execution time is the off-line propagation of Landsat based truth images to the fixed grid coordinates system for each of the three GOES-R satellite locations, operational East and West and initial checkout locations. This paper describes the algorithmic design and implementation of IPATS and provides preliminary test results.

  11. Natural cavity characteristics and cavity bird abundance on West Virginia forested islands of the Ohio River

    Treesearch

    James T. Anderson; Karen A. Riesz

    2013-01-01

    Wildlife habitats connected with forested islands and their back channels (areas where commercial traffic is prohibited) on the Ohio River are valuable to diverse species. However, quantitative data on the importance of these areas to cavity-nesting birds are lacking. We compared cavity-nesting bird use and habitat between back and navigational channel sides of islands...

  12. A three-dimensional dynamical model for channeled lava flow with nonlinear rheology

    NASA Astrophysics Data System (ADS)

    Filippucci, Marilena; Tallarico, Andrea; Dragoni, Michele

    2010-05-01

    Recent laboratory studies on the rheology of lava samples from different volcanic areas have highlighted that the apparent viscosity depends on a power of the strain rate. Several authors agree in attributing this dependence to the crystal content of the sample and to temperature. Starting from these results, in this paper we studied the effect of a power law rheology on a gravity-driven lava flow. The equation of motion is nonlinear in the diffusion term, and an analytical solution does not seem to be possible. The finite-volume method has been applied to solve numerically the equation governing the fully developed laminar flow of a power law non-Newtonian fluid in an inclined rectangular channel. The convergence, the stability, and the order of approximation were tested for the Newtonian rheology case, comparing the numerical solution with the available analytical solution. Results indicate that the assumption on the rheology, whether linear or nonlinear, strongly affects the velocity and/or the thickness of the lava channel both for channels with fixed geometry and for channels with constant flow rate. Results on channels with fixed geometry are confirmed by some simulations for real lava channels. Finally, the study of the Reynolds number indicates that gravity-driven lava channel flows are always in laminar regime, except for strongly nonlinear pseudoplastic fluids with low fluid consistency and at high slopes.

  13. Flow structure, heat transfer and pressure drop in varying aspect ratio two-pass rectangular smooth channels

    NASA Astrophysics Data System (ADS)

    Siddique, Waseem; El-Gabry, Lamyaa; Shevchuk, Igor V.; Hushmandi, Narmin B.; Fransson, Torsten H.

    2012-05-01

    Two-pass channels are used for internal cooling in a number of engineering systems e.g., gas turbines. Fluid travelling through the curved path, experiences pressure and centrifugal forces, that result in pressure driven secondary motion. This motion helps in moving the cold high momentum fluid from the channel core to the side walls and plays a significant role in the heat transfer in the channel bend and outlet pass. The present study investigates using Computational Fluid Dynamics (CFD), the flow structure, heat transfer enhancement and pressure drop in a smooth channel with varying aspect ratio channel at different divider-to-tip wall distances. Numerical simulations are performed in two-pass smooth channel with aspect ratio Win/H = 1:3 at inlet pass and Wout/H = 1:1 at outlet pass for a variety of divider-to-tip wall distances. The results show that with a decrease in aspect ratio of inlet pass of the channel, pressure loss decreases. The divider-to-tip wall distance (Wel) not only influences the pressure drop, but also the heat transfer enhancement at the bend and outlet pass. With an increase in the divider-to-tip wall distance, the areas of enhanced heat transfer shifts from side walls of outlet pass towards the inlet pass. To compromise between heat transfer and pressure drop in the channel, Wel/H = 0.88 is found to be optimum for the channel under study.

  14. A Review of Boiling Heat Transfer Processes at High Heat Flux

    DTIC Science & Technology

    1991-04-01

    Hydrogen on Burnout for Water Flowing Vertically Upward in Round Tubes at 2000 psia," WAPD - TH-318, April 1957. 100. Doroschuck, V. E. and Lantsman, F. P...34Forced-Convection Heat Transfer Burnout Studies for Water in Rectangular Channels and Round Tubes at Pressures above 500 psia," USAEC Rept. WAPD ...Volumes in Subcooled Boiling Systems, ASME Paper 58-HT-19, 1958. 264 . Core, T. C. and Sato, K., "Determination of Burnout Limits of Polyphenyl Coolants

  15. DISCHARGE AND DEPTH BEHIND A PARTIALLY BREACHED DAM.

    USGS Publications Warehouse

    Chen, Cheng-lung

    1987-01-01

    The role that the velocity-distribution correction factor plays in the determination of the flood discharge and corresponding flow depth behind a partially breached dam is investigated. Assumption of a uniformly progressive flow for an established dam-break flood in a rectangular channel of infinite extent leads to the formulation of a theoretical relation between the depth and velocity of flow expressed in differential form. Integrating this ordinary differential equation, one can express the velocity in terms of the depth.

  16. Hierarchical image coding with diamond-shaped sub-bands

    NASA Technical Reports Server (NTRS)

    Li, Xiaohui; Wang, Jie; Bauer, Peter; Sauer, Ken

    1992-01-01

    We present a sub-band image coding/decoding system using a diamond-shaped pyramid frequency decomposition to more closely match visual sensitivities than conventional rectangular bands. Filter banks are composed of simple, low order IIR components. The coder is especially designed to function in a multiple resolution reconstruction setting, in situations such as variable capacity channels or receivers, where images must be reconstructed without the entire pyramid of sub-bands. We use a nonlinear interpolation technique for lost subbands to compensate for loss of aliasing cancellation.

  17. GPS Integrity Channel RTCA Working Group recommendations

    NASA Astrophysics Data System (ADS)

    Kalafus, Rudolph M.

    Recommendations made by a working group established by the Radio Technical Commission for Aeronautics are presented for the design of a wide-area broadcast service to provide indications on the status of GPS satellites. The integrity channel requirements and operational goals are outlined. Six integrity channel system concepts are considered and system design and time-to-alarm considerations are examined. The recommended system includes the broadcast of a coarse range measurement for each satellite which will enable the on-board GPS receiver to determine whether or not the navigation accuracy is within prescribed limits.

  18. Enhancement of magneto-optical Faraday effects and extraordinary optical transmission in a tri-layer structure with rectangular annular arrays.

    PubMed

    Lei, Chengxin; Chen, Leyi; Tang, Zhixiong; Li, Daoyong; Cheng, Zhenzhi; Tang, Shaolong; Du, Youwei

    2016-02-15

    The properties of optics and magneto-optical Faraday effects in a metal-dielectric tri-layer structure with subwavelength rectangular annular arrays are investigated. It is noteworthy that we obtained the strongly enhanced Faraday rotation of the desired sign along with high transmittance by optimizing the parameters of the nanostructure in the visible spectral ranges. In this system, we obtained two extraordinary optical transmission (EOT) resonant peaks with enhanced Faraday rotations, whose signs are opposite, which may provide the possibility of designing multi-channel magneto-optical devices. Study results show that the maximum of the figure of merit (FOM) of the structure can be obtained between two EOT resonant peaks accompanied by an enhanced Faraday rotation. The positions of the maximum value of the FOM and resonant peaks of transmission along with a large Faraday rotation can be tailored by simply adjusting the geometric parameters of our models. These research findings are of great importance for future applications of magneto-optical devices.

  19. 78 FR 38975 - Environmental Impacts Statements; Notice of Availability

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-28

    ... Everglades Harbor Navigation Improvements, Comment Period Ends: 08/13/2013, Contact: Terri Jordan-Sellers 904... Channel Ocean Dredged Material Disposal Site West, Pursuant to Section 102(c) of the Marine Protection...

  20. Numerics made easy: solving the Navier-Stokes equation for arbitrary channel cross-sections using Microsoft Excel.

    PubMed

    Richter, Christiane; Kotz, Frederik; Giselbrecht, Stefan; Helmer, Dorothea; Rapp, Bastian E

    2016-06-01

    The fluid mechanics of microfluidics is distinctively simpler than the fluid mechanics of macroscopic systems. In macroscopic systems effects such as non-laminar flow, convection, gravity etc. need to be accounted for all of which can usually be neglected in microfluidic systems. Still, there exists only a very limited selection of channel cross-sections for which the Navier-Stokes equation for pressure-driven Poiseuille flow can be solved analytically. From these equations, velocity profiles as well as flow rates can be calculated. However, whenever a cross-section is not highly symmetric (rectangular, elliptical or circular) the Navier-Stokes equation can usually not be solved analytically. In all of these cases, numerical methods are required. However, in many instances it is not necessary to turn to complex numerical solver packages for deriving, e.g., the velocity profile of a more complex microfluidic channel cross-section. In this paper, a simple spreadsheet analysis tool (here: Microsoft Excel) will be used to implement a simple numerical scheme which allows solving the Navier-Stokes equation for arbitrary channel cross-sections.

  1. In situ and online monitoring of hydrodynamic flow profiles in microfluidic channels based upon microelectrochemistry: concept, theory, and validation.

    PubMed

    Amatore, Christian; Oleinick, Alexander; Klymenko, Oleksiy V; Svir, Irina

    2005-08-12

    Herein, we propose a method for reconstructing any plausible macroscopic hydrodynamic flow profile occurring locally within a rectangular microfluidic channel. The method is based on experimental currents measured at single or double microband electrodes embedded in one channel wall. A perfectly adequate quasiconformal mapping of spatial coordinates introduced in our previous work [Electrochem. Commun. 2004, 6, 1123] and an exponentially expanding time grid, initially proposed [J. Electroanal. Chem. 2003, 557, 75] in conjunction with the solution of the corresponding variational problem approached by the Ritz method are used for the numerical reconstruction of flow profiles. Herein, the concept of the method is presented and developed theoretically and its validity is tested on the basis of the use of pseudoexperimental currents emulated by simulation of the diffusion-convection problem in a channel flow cell, to which a random Gaussian current noise is added. The flow profiles reconstructed by our method compare successfully with those introduced a priori into the simulations, even when these include significant distortions compared with either classical Poiseuille or electro-osmotic flows.

  2. An Experimental Design of Bypass Magneto-Rheological (MR) damper

    NASA Astrophysics Data System (ADS)

    Rashid, MM; Aziz, Mohammad Abdul; Raisuddin Khan, Md.

    2017-11-01

    The magnetorheological (MR) fluid bypass damper fluid flow through a bypass by utilizing an external channel which allows the controllability of MR fluid in the channel. The Bypass MR damper (BMRD) contains a rectangular bypass flow channel, current controlled movable piston shaft arrangement and MR fluid. The static piston coil case is winding by a coil which is used inside the piston head arrangement. The current controlled coil case provides a magnetic flux through the BMRD cylinder for controllability. The high strength of alloy steel materials are used for making piston shaft which allows magnetic flux propagation throughout the BMRD cylinder. Using the above design materials, a Bypass MR damper is designed and tested. An excitation of current is applied during the experiment which characterizes the BMRD controllability. It is shown that the BMRD with external flow channel allows a high controllable damping force using an excitation current. The experimental result of damping force-displacement characteristics with current excitation and without current excitation are compared in this research. The BMRD model is validated by the experimental result at various frequencies and applied excitation current.

  3. Nuclear reactor

    DOEpatents

    Thomson, Wallace B.

    2004-03-16

    A nuclear reactor comprising a cylindrical pressure vessel, an elongated annular core centrally disposed within and spaced from the pressure vessel, and a plurality of ducts disposed longitudinally of the pressure vessel about the periphery thereof, said core comprising an annular active portion, an annular reflector just inside the active portion, and an annular reflector just outside the active a portion, said annular active portion comprising rectangular slab, porous fuel elements radially disposed around the inner reflector and extending the length of the active portion, wedge-shaped, porous moderator elements disposed adjacent one face of each fuel element and extending the length of the fuel element, the fuel and moderator elements being oriented so that the fuel elements face each other and the moderator elements do likewise, adjacent moderator elements being spaced to provide air inlet channels, and adjacent fuel elements being spaced to provide air outlet channels which communicate with the interior of the peripheral ducts, and means for introducing air into the air inlet channels which passes through the porous moderator elements and porous fuel elements to the outlet channel.

  4. Real-time differential GPS/GLONASS trials in Europe using all-in-view 20-channel receivers

    NASA Astrophysics Data System (ADS)

    Capaccio, S.; Lowe, D.; Walsh, D. M. A.; Daly, P.

    Following the initial development of 20-channel, all-in-view Global Navigation Satellite System (GNSS), GPS/GLONASS/Inmarsat-3, receivers at the Institute of Satellite Navigation (ISN), University of Leeds, a modification programme has been undertaken to allow real-time differential corrections to be sent from one 20-channel receiver to another identical receiver using a serial link between them. The differential correction software incorporates the RTCM SC-104 and RTCA DO-217 format developed specifically for GPS and adjusted by the ISN to allow simultaneous GLONASS operation.After successful laboratory testing, real-time differential GNSS tests were successfully completed in static mode between Aberdeen and Leeds via the SkyFix differential data-link, and in dynamic mode at DTEO Boscombe Down using a C-band data-link between the ground and a receiver on board the DRA BAC 1-11 aircraft. The aims of the tests were, (i) to demonstrate real-time differential GNSS position-fixing, (ii) to establish the accuracy improvements brought about, and (iii) to examine the effects of data-link latency and satellite PDOP on the solution accuracy.

  5. Precision Time Protocol-Based Trilateration for Planetary Navigation

    NASA Technical Reports Server (NTRS)

    Murdock, Ron

    2015-01-01

    Progeny Systems Corporation has developed a high-fidelity, field-scalable, non-Global Positioning System (GPS) navigation system that offers precision localization over communications channels. The system is bidirectional, providing position information to both base and mobile units. It is the first-ever wireless use of the Institute of Electrical and Electronics Engineers (IEEE) Precision Time Protocol (PTP) in a bidirectional trilateration navigation system. The innovation provides a precise and reliable navigation capability to support traverse-path planning systems and other mapping applications, and it establishes a core infrastructure for long-term lunar and planetary occupation. Mature technologies are integrated to provide navigation capability and to support data and voice communications on the same network. On Earth, the innovation is particularly well suited for use in unmanned aerial vehicles (UAVs), as it offers a non-GPS precision navigation and location service for use in GPS-denied environments. Its bidirectional capability provides real-time location data to the UAV operator and to the UAV. This approach optimizes assisted GPS techniques and can be used to determine the presence of GPS degradation, spoofing, or jamming.

  6. Predominance of sperm motion in corners.

    PubMed

    Nosrati, Reza; Graham, Percival J; Liu, Qiaozhi; Sinton, David

    2016-05-23

    Sperm migration through the female tract is crucial to fertilization, but the role of the complex and confined structure of the fallopian tube in sperm guidance remains unknown. Here, by confocal imaging microchannels head-on, we distinguish corner- vs. wall- vs. bulk-swimming bull sperm in confined geometries. Corner-swimming dominates with local areal concentrations as high as 200-fold that of the bulk. The relative degree of corner-swimming is strongest in small channels, decreases with increasing channel size, and plateaus for channels above 200 μm. Corner-swimming remains predominant across the physiologically-relevant range of viscosity and pH. Together, boundary-following sperm account for over 95% of the sperm distribution in small rectangular channels, which is similar to the percentage of wall swimmers in circular channels of similar size. We also demonstrate that wall-swimming sperm travel closer to walls in smaller channels (~100 μm), where the opposite wall is within the hydrodynamic interaction length-scale. The corner accumulation effect is more than the superposition of the influence of two walls, and over 5-fold stronger than that of a single wall. These findings suggest that folds and corners are dominant in sperm migration in the narrow (sub-mm) lumen of the fallopian tube and microchannel-based sperm selection devices.

  7. Predominance of sperm motion in corners

    PubMed Central

    Nosrati, Reza; Graham, Percival J.; Liu, Qiaozhi; Sinton, David

    2016-01-01

    Sperm migration through the female tract is crucial to fertilization, but the role of the complex and confined structure of the fallopian tube in sperm guidance remains unknown. Here, by confocal imaging microchannels head-on, we distinguish corner- vs. wall- vs. bulk-swimming bull sperm in confined geometries. Corner-swimming dominates with local areal concentrations as high as 200-fold that of the bulk. The relative degree of corner-swimming is strongest in small channels, decreases with increasing channel size, and plateaus for channels above 200 μm. Corner-swimming remains predominant across the physiologically-relevant range of viscosity and pH. Together, boundary-following sperm account for over 95% of the sperm distribution in small rectangular channels, which is similar to the percentage of wall swimmers in circular channels of similar size. We also demonstrate that wall-swimming sperm travel closer to walls in smaller channels (~100 μm), where the opposite wall is within the hydrodynamic interaction length-scale. The corner accumulation effect is more than the superposition of the influence of two walls, and over 5-fold stronger than that of a single wall. These findings suggest that folds and corners are dominant in sperm migration in the narrow (sub-mm) lumen of the fallopian tube and microchannel-based sperm selection devices. PMID:27211846

  8. The Debye-Huckel Approximation in Electroosmotic Flow in Micro- and Nano-channels

    NASA Astrophysics Data System (ADS)

    Conlisk, A. Terrence

    2002-11-01

    In this work we consider the electroosmotic flow in a rectangular channel. We consider a mixture of water or other neutral solvent and a salt compound such as sodium chloride and other buffers for which the ionic species are entirely dissociated. Results are produced for the case where the channel height is much greater than the electric double layer(EDL)(microchannel) and for the case where the channel height is of the order or slightly greater than the width of the EDL(nanochannel). At small cation, anion concentration differences the Debye-Huckel approximation is appropriate; at larger concentration differences, the Gouy-Chapman picture of the electric double emerges naturally. In the symmetric case for the electroosmotic flow so induced, the velocity field and the potential are similar. We specifically focus in this paper on the limits of the Debye-Huckel approximation for a simplified version of a phosphate buffered saline(PBS) mixture. The fluid is assumed to behave as a continuum and the volume flow rate is observed to vary linearly with channel height for electrically driven flow in contrast to pressure driven flow which varies as height cubed. This means that very large pressure drops are required to drive flows in small channels. However, useful volume flow rates may be obtained at a very low driving voltage.

  9. 33 CFR 100.35T05-0276 - Special Local Regulations for Marine Events; Potomac River, National Harbor Access Channel, MD.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Marine Events; Potomac River, National Harbor Access Channel, MD. 100.35T05-0276 Section 100.35T05-0276... SAFETY OF LIFE ON NAVIGABLE WATERS § 100.35T05-0276 Special Local Regulations for Marine Events; Potomac... area: All waters of the Potomac River, within lines connecting the following positions: From 38°47′35...

  10. 33 CFR 100.35T05-0276 - Special Local Regulations for Marine Events; Potomac River, National Harbor Access Channel, MD.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Marine Events; Potomac River, National Harbor Access Channel, MD. 100.35T05-0276 Section 100.35T05-0276... SAFETY OF LIFE ON NAVIGABLE WATERS § 100.35T05-0276 Special Local Regulations for Marine Events; Potomac... area: All waters of the Potomac River, within lines connecting the following positions: From 38°47′35...

  11. Advancing Underwater Acoustic Communication for Autonomous Distributed Networks via Sparse Channel Sensing, Coding, and Navigation Support

    DTIC Science & Technology

    2011-09-30

    channel interference mitigation for underwater acoustic MIMO - OFDM . 3) Turbo equalization for OFDM modulated physical layer network coding. 4) Blind CFO...Underwater Acoustic MIMO - OFDM . MIMO - OFDM has been actively studied for high data rate communications over the bandwidthlimited underwater acoustic...with the cochannel interference (CCI) due to parallel transmissions in MIMO - OFDM . Our proposed receiver has the following components: 1

  12. A dimensional comparison between embedded 3D-printed and silicon microchannels

    NASA Astrophysics Data System (ADS)

    O'Connor, J.; Punch, J.; Jeffers, N.; Stafford, J.

    2014-07-01

    The subject of this paper is the dimensional characterization of embedded microchannel arrays created using contemporary 3D-printing fabrication techniques. Conventional microchannel arrays, fabricated using deep reactive ion etching techniques (DRIE) and wet-etching (KOH), are used as a benchmark for comparison. Rectangular and trapezoidal cross-sectional shapes were investigated. The channel arrays were 3D-printed in vertical and horizontal directions, to examine the influence of print orientation on channel characteristics. The 3D-printed channels were benchmarked against Silicon channels in terms of the following dimensional characteristics: cross-sectional area (CSA), perimeter, and surface profiles. The 3D-printed microchannel arrays demonstrated variances in CSA of 6.6-20% with the vertical printing approach yielding greater dimensional conformity than the horizontal approach. The measured CSA and perimeter of the vertical channels were smaller than the nominal dimensions, while the horizontal channels were larger in both CSA and perimeter due to additional side-wall roughness present throughout the channel length. This side-wall roughness caused significant shape distortion. Surface profile measurements revealed that the base wall roughness was approximately the resolution of current 3D-printers. A spatial periodicity was found along the channel length which appeared at different frequencies for each channel array. This paper concludes that vertical 3D-printing is superior to the horizontal printing approach, in terms of both dimensional fidelity and shape conformity and can be applied in microfluidic device applications.

  13. Quasi-3D Modeling and Efficient Simulation of Laminar Flows in Microfluidic Devices.

    PubMed

    Islam, Md Zahurul; Tsui, Ying Yin

    2016-10-03

    A quasi-3D model has been developed to simulate the flow in planar microfluidic systems with low Reynolds numbers. The model was developed by decomposing the flow profile along the height of a microfluidic system into a Fourier series. It was validated against the analytical solution for flow in a straight rectangular channel and the full 3D numerical COMSOL Navier-Stokes solver for flow in a T-channel. Comparable accuracy to the full 3D numerical solution was achieved by using only three Fourier terms with a significant decrease in computation time. The quasi-3D model was used to model flows in a micro-flow cytometer chip on a desktop computer and good agreement between the simulation and the experimental results was found.

  14. Quasi-3D Modeling and Efficient Simulation of Laminar Flows in Microfluidic Devices

    PubMed Central

    Islam, Md. Zahurul; Tsui, Ying Yin

    2016-01-01

    A quasi-3D model has been developed to simulate the flow in planar microfluidic systems with low Reynolds numbers. The model was developed by decomposing the flow profile along the height of a microfluidic system into a Fourier series. It was validated against the analytical solution for flow in a straight rectangular channel and the full 3D numerical COMSOL Navier-Stokes solver for flow in a T-channel. Comparable accuracy to the full 3D numerical solution was achieved by using only three Fourier terms with a significant decrease in computation time. The quasi-3D model was used to model flows in a micro-flow cytometer chip on a desktop computer and good agreement between the simulation and the experimental results was found. PMID:27706104

  15. A numerical study of blood flow using mixture theory

    PubMed Central

    Wu, Wei-Tao; Aubry, Nadine; Massoudi, Mehrdad; Kim, Jeongho; Antaki, James F.

    2014-01-01

    In this paper, we consider the two dimensional flow of blood in a rectangular microfluidic channel. We use Mixture Theory to treat this problem as a two-component system: One component is the red blood cells (RBCs) modeled as a generalized Reiner–Rivlin type fluid, which considers the effects of volume fraction (hematocrit) and influence of shear rate upon viscosity. The other component, plasma, is assumed to behave as a linear viscous fluid. A CFD solver based on OpenFOAM® was developed and employed to simulate a specific problem, namely blood flow in a two dimensional micro-channel, is studied. Finally to better understand this two-component flow system and the effects of the different parameters, the equations are made dimensionless and a parametric study is performed. PMID:24791016

  16. Effects of turn region treatments on pressure loss through sharp 180-degree bends

    NASA Astrophysics Data System (ADS)

    Plevich, C. W.; Metzger, D. E.

    An experimental study was conducted to evaluate the effect of geometric turn region inserts on pressure losses for flow through sharp 180-degree channel turns typical of internal cooling passages in gas turbine engine airfoils. The experiments were conducted in a rectangular cross-sectioned channel with 90-degree transverse rib roughening in both inlet and outlet legs, starting with completely smooth turn regions and progressing through various modifications including corner fillets, radial ribs, and turning vanes. The results show that modifications to the turn region geometry, particularly the inclusion of a single semi-circular turning vane, significantly reduce the pressure losses associated with coolant flows through sharp 180-degree turns and therefore can result in increased coolant flow for a given coolant supply pressure.

  17. A numerical study of blood flow using mixture theory.

    PubMed

    Wu, Wei-Tao; Aubry, Nadine; Massoudi, Mehrdad; Kim, Jeongho; Antaki, James F

    2014-03-01

    In this paper, we consider the two dimensional flow of blood in a rectangular microfluidic channel. We use Mixture Theory to treat this problem as a two-component system: One component is the red blood cells (RBCs) modeled as a generalized Reiner-Rivlin type fluid, which considers the effects of volume fraction (hematocrit) and influence of shear rate upon viscosity. The other component, plasma, is assumed to behave as a linear viscous fluid. A CFD solver based on OpenFOAM ® was developed and employed to simulate a specific problem, namely blood flow in a two dimensional micro-channel, is studied. Finally to better understand this two-component flow system and the effects of the different parameters, the equations are made dimensionless and a parametric study is performed.

  18. Flow structure and heat exchange analysis in internal cooling channel of gas turbine blade

    NASA Astrophysics Data System (ADS)

    Szwaba, Ryszard; Kaczynski, Piotr; Doerffer, Piotr; Telega, Janusz

    2016-08-01

    This paper presents the study of the flow structure and heat transfer, and also their correlations on the four walls of a radial cooling passage model of a gas turbine blade. The investigations focus on heat transfer and aerodynamic measurements in the channel, which is an accurate representation of the configuration used in aeroengines. Correlations for the heat transfer coefficient and the pressure drop used in the design of radial cooling passages are often developed from simplified models. It is important to note that real engine passages do not have perfect rectangular cross sections, but include corner fillet, ribs with fillet radii and special orientation. Therefore, this work provides detailed fluid flow and heat transfer data for a model of radial cooling geometry which possesses very realistic features.

  19. Ejection mechanisms in the sublayer of a turbulent channel

    NASA Technical Reports Server (NTRS)

    Jimenez, J.; Moin, P.; Moser, R. D.; Keefe, L. R.

    1987-01-01

    A possible model for the inception of vorticity ejections in the viscous sublayer of a turbulent rectangular channel is presented. It was shown that this part of the flow is dominated by protruding strong shear layers of z-vorticity, and it was proposed as a mechanism for their maintenance and reproduction which is essentially equivalent to that responsible for the instability of 2-D Tollmien-Schlichting waves. The efforts to isolate computationally a single structure for its study have failed up to now, since it appears that single structures decay in the absence of external forcing, but a convenient computation model was identified in the form of a long and narrow periodic computational box containing at each moment only a few structures. Further work in the identification of better reduced systems is in progress.

  20. Water Quality Conditions in the Missouri River Mainstem System. 2009 Report

    DTIC Science & Technology

    2010-09-01

    Navigation Channel Reach ............................................................................. 117  6.2  Flow Regulation...118  6.2.2  Historic Flow Releases...118  6.2.3  Flow Releases for Water Quality management

  1. 49 CFR Appendix B to Part 194 - High Volume Areas

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Glaise, AR. Wisconsin River Wisconsin Rapids, WI. Yukon River Fairbanks, AK. Other Navigable Waters Arthur Kill Channel, NY Cook Inlet, AK Freeport, TX Los Angeles/Long Beach Harbor, CA Port Lavaca, TX San...

  2. 49 CFR Appendix B to Part 194 - High Volume Areas

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Glaise, AR. Wisconsin River Wisconsin Rapids, WI. Yukon River Fairbanks, AK. Other Navigable Waters Arthur Kill Channel, NY Cook Inlet, AK Freeport, TX Los Angeles/Long Beach Harbor, CA Port Lavaca, TX San...

  3. 49 CFR Appendix B to Part 194 - High Volume Areas

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Glaise, AR. Wisconsin River Wisconsin Rapids, WI. Yukon River Fairbanks, AK. Other Navigable Waters Arthur Kill Channel, NY Cook Inlet, AK Freeport, TX Los Angeles/Long Beach Harbor, CA Port Lavaca, TX San...

  4. 49 CFR Appendix B to Part 194 - High Volume Areas

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Glaise, AR. Wisconsin River Wisconsin Rapids, WI. Yukon River Fairbanks, AK. Other Navigable Waters Arthur Kill Channel, NY Cook Inlet, AK Freeport, TX Los Angeles/Long Beach Harbor, CA Port Lavaca, TX San...

  5. Multichannel seismic-reflection data collected in 1980 in the eastern Chukchi Sea

    USGS Publications Warehouse

    Grantz, Arthur; Mann, Dennis M.; May, Steven D.

    1986-01-01

    The U.S. Geological Survey (USGS) collected approximately 2,652 km of 24-channel seismic-reflection data in early September, 1980, over the continental shelf in the eastern Chukchi Sea (Fig. 1). The profiles were collected on the USGS Research Vessel S.P. Lee. The seismic energy source consisted of a tuned array of five airguns with a total volume of 1213 cubic inches of air compressed to approximately 1900 psi. The recording system consisted of a 24-channel, 2400 meter long streamer with a group interval of 100 m, and a GUS (Global Universal Science) model 4200 digital recording instrument. Shots were fired every 50 meters. Navigational control for the survey was provided by a Magnavox integrated navigation system using transit satellites and doppler-sonar augmented by Loran C (Rho-Rho). A 2-millisecond sampling rate was used in the field; the data were later desampled to 4-milliseconds during the demultiplexing process. 8 seconds data length was recorded. Processing was done at the USGS Pacific Marine Geology Multichannel Processing Center in Menlo Park, California, in the sequence: editing-demultiplexing, velocity analysis, CDP stacking, deconvolution-filtering, and plotting on an electrostatic plotter. Plate 1 is a trackline chart showing shotpoint navigation.

  6. Non-rigid Motion Correction in 3D Using Autofocusing with Localized Linear Translations

    PubMed Central

    Cheng, Joseph Y.; Alley, Marcus T.; Cunningham, Charles H.; Vasanawala, Shreyas S.; Pauly, John M.; Lustig, Michael

    2012-01-01

    MR scans are sensitive to motion effects due to the scan duration. To properly suppress artifacts from non-rigid body motion, complex models with elements such as translation, rotation, shear, and scaling have been incorporated into the reconstruction pipeline. However, these techniques are computationally intensive and difficult to implement for online reconstruction. On a sufficiently small spatial scale, the different types of motion can be well-approximated as simple linear translations. This formulation allows for a practical autofocusing algorithm that locally minimizes a given motion metric – more specifically, the proposed localized gradient-entropy metric. To reduce the vast search space for an optimal solution, possible motion paths are limited to the motion measured from multi-channel navigator data. The novel navigation strategy is based on the so-called “Butterfly” navigators which are modifications to the spin-warp sequence that provide intrinsic translational motion information with negligible overhead. With a 32-channel abdominal coil, sufficient number of motion measurements were found to approximate possible linear motion paths for every image voxel. The correction scheme was applied to free-breathing abdominal patient studies. In these scans, a reduction in artifacts from complex, non-rigid motion was observed. PMID:22307933

  7. Flow rate-pressure drop relation for deformable shallow microfluidic channels

    NASA Astrophysics Data System (ADS)

    Christov, Ivan C.; Cognet, Vincent; Shidhore, Tanmay C.; Stone, Howard A.

    2018-04-01

    Laminar flow in devices fabricated from soft materials causes deformation of the passage geometry, which affects the flow rate--pressure drop relation. For a given pressure drop, in channels with narrow rectangular cross-section, the flow rate varies as the cube of the channel height, so deformation can produce significant quantitative effects, including nonlinear dependence on the pressure drop [{Gervais, T., El-Ali, J., G\\"unther, A. \\& Jensen, K.\\ F.}\\ 2006 Flow-induced deformation of shallow microfluidic channels.\\ \\textit{Lab Chip} \\textbf{6}, 500--507]. Gervais et. al. proposed a successful model of the deformation-induced change in the flow rate by heuristically coupling a Hookean elastic response with the lubrication approximation for Stokes flow. However, their model contains a fitting parameter that must be found for each channel shape by performing an experiment. We present a perturbation approach for the flow rate--pressure drop relation in a shallow deformable microchannel using the theory of isotropic quasi-static plate bending and the Stokes equations under a lubrication approximation (specifically, the ratio of the channel's height to its width and of the channel's height to its length are both assumed small). Our result contains no free parameters and confirms Gervais et. al.'s observation that the flow rate is a quartic polynomial of the pressure drop. The derived flow rate--pressure drop relation compares favorably with experimental measurements.

  8. Particle size distribution of main-channel-bed sediments along the upper Mississippi River, USA

    USGS Publications Warehouse

    Remo, Jonathan; Heine, Ruben A.; Ickes, Brian

    2016-01-01

    In this study, we compared pre-lock-and-dam (ca. 1925) with a modern longitudinal survey of main-channel-bed sediments along a 740-km segment of the upper Mississippi River (UMR) between Davenport, IA, and Cairo, IL. This comparison was undertaken to gain a better understanding of how bed sediments are distributed longitudinally and to assess change since the completion of the UMR lock and dam navigation system and Missouri River dams (i.e., mid-twentieth century). The comparison of the historic and modern longitudinal bed sediment surveys showed similar bed sediment sizes and distributions along the study segment with the majority (> 90%) of bed sediment samples having a median diameter (D50) of fine to coarse sand. The fine tail (≤ D10) of the sediment size distributions was very fine to medium sand, and the coarse tail (≥ D90) of sediment-size distribution was coarse sand to gravel. Coarsest sediments in both surveys were found within or immediately downstream of bedrock-floored reaches. Statistical analysis revealed that the particle-size distributions between the survey samples were statistically identical, suggesting no overall difference in main-channel-bed sediment-size distribution between 1925 and present. This was a surprising result given the magnitude of river engineering undertaken along the study segment over the past ~ 90 years. The absence of substantial differences in main-channel-bed-sediment size suggests that flow competencies within the highly engineered navigation channel today are similar to conditions within the less-engineered historic channel.

  9. Near-bed turbulence and sediment flux measurements in tidal channels

    USGS Publications Warehouse

    Wright, S.A.; Whealdon-Haught, D.R.

    2012-01-01

    Understanding the hydrodynamics and sediment transport dynamics in tidal channels is important for studies of estuary geomorphology, sediment supply to tidal wetlands, aquatic ecology and fish habitat, and dredging and navigation. Hydrodynamic and sediment transport data are essential for calibration and testing of numerical models that may be used to address management questions related to these topics. Herein we report preliminary analyses of near-bed turbulence and sediment flux measurements in the Sacramento-San Joaquin Delta, a large network of tidal channels and wetlands located at the confluence of the Sacramento and San Joaquin Rivers, California, USA (Figure 1). Measurements were made in 6 channels spanning a wide range of size and tidal conditions, from small channels that are primarily fluvial to large channels that are tidally dominated. The results of these measurements are summarized herein and the hydrodynamic and sediment transport characteristics of the channels are compared across this range of size and conditions.

  10. Biased migration of confined neutrophil-like cells in asymmetric hydraulic environments.

    PubMed

    Prentice-Mott, Harrison V; Chang, Chi-Han; Mahadevan, L; Mitchison, Timothy J; Irimia, Daniel; Shah, Jagesh V

    2013-12-24

    Cells integrate multiple measurement modalities to navigate their environment. Soluble and substrate-bound chemical gradients and physical cues have all been shown to influence cell orientation and migration. Here we investigate the role of asymmetric hydraulic pressure in directional sensing. Cells confined in microchannels identified and chose a path of lower hydraulic resistance in the absence of chemical cues. In a bifurcating channel with asymmetric hydraulic resistances, this choice was preceded by the elaboration of two leading edges with a faster extension rate along the lower resistance channel. Retraction of the "losing" edge appeared to precipitate a final choice of direction. The pressure differences altering leading edge protrusion rates were small, suggesting weak force generation by leading edges. The response to the physical asymmetry was able to override a dynamically generated chemical cue. Motile cells may use this bias as a result of hydraulic resistance, or "barotaxis," in concert with chemotaxis to navigate complex environments.

  11. Identification of Challenges and Opportunities for Regional Sediment Management (RSM) and Engineering with Nature (EWN) within Inland USACE Districts

    DTIC Science & Technology

    2016-07-01

    sediment dredging activities in support of navigation channel maintenance with resultant direct beach placement or nearshore placement were common...watershed and stream channel erosion prevention. • Identify sediment resources and flux in and out of the flood plain and create sediment budgets...Regional Sediment Management (RSM) and Engineering With Nature (EWN) within Inland USACE Districts by Katherine Touzinsky, Paul Boyd, and John

  12. Interim Feasibility Report and Draft Environmental Impact Statement, Grays Harbor, Chehalis and Hoquiam Rivers, Washington, Channel Improvements for Navigation.

    DTIC Science & Technology

    1982-06-01

    these conditions . Therefore, the no-action plan is not being recommended. With the present channel conditions and anticipated slow growth for... conditions very similar to those of today. No ocean disposal is anticipated. Because no significant growth in socioeconomic activity is expected without...accuracy; however, project construction provides conditions favorable for growth . The service industry would be expected to closely follow any increase

  13. Numerical Modeling of Three-Dimensional Confined Flows

    NASA Technical Reports Server (NTRS)

    Greywall, M. S.

    1981-01-01

    A three dimensional confined flow model is presented. The flow field is computed by calculating velocity and enthalpy along a set of streamlines. The finite difference equations are obtained by applying conservation principles to streamtubes constructed around the chosen streamlines. With appropriate substitutions for the body force terms, the approach computes three dimensional magnetohydrodynamic channel flows. A listing of a computer code, based on this approach is presented in FORTRAN IV language. The code computes three dimensional compressible viscous flow through a rectangular duct, with the duct cross section specified along the axis.

  14. Peculiarities of heat transfer at the liquid metal flow in a vertical channel in a coplanar magnetic field

    NASA Astrophysics Data System (ADS)

    Razuvanov, N. G.; Poddubnyi, I. I.; Kostychev, P. V.

    2017-11-01

    The research of hydrodynamics and heat transfer at the liquid metal (LM) downward flow and upflow in a vertical duct of a rectangular cross section with a ratio of sides ˜1/3 in a coplanar magnetic field (MF) under conditions of bilateral symmetrical heating is performed. The problem simulates the LM flow in the heat exchange channels for cooling the liquid metal module of the blanket of the thermonuclear reactor (TNR) of the TOKAMAK type. The experiments were carried out on the basis of the mercury magnetohydrodynamic test-bed (MHD) Moscow Power Engineering Institute (MPEI) - Joint Institute for High Temperatures of the Russian Academy of Sciences (JIHT RAS). The probe measurement technique was used in the flow. Profiles of averaged velocity and averaged temperature, as well as profiles of temperature pulsations in the axial planes of the channel cross-section, are obtained; the distribution of the dimensionless wall temperature along the perimeter unfolding of the channel in the section and along the length of the channel. A significant effect of thermogravitational convection (TGC), which leads to unexpected effects, is found. At the downflow in a magnetic field, in some modes, low-frequency pulsations of anomalously high intensity occur.

  15. The motion of a train of vesicles in channel flow

    NASA Astrophysics Data System (ADS)

    Barakat, Joseph; Shaqfeh, Eric

    2017-11-01

    The inertialess motion of a train of lipid-bilayer vesicles flowing through a channel is simulated using a 3D boundary integral equation method. Steady-state results are reported for vesicles positioned concentrically inside cylindrical channels of circular, square, and rectangular cross sections. The vesicle translational velocity U and excess channel pressure drop Δp+ depend strongly on the ratio of the vesicle radius to the hydraulic radius λ and the vesicle reduced volume υ. ``Deflated vesicles'' of lower reduced volume υ are more streamlined and translate with greater velocity U relative to the mean flow velocity V. Increasing the vesicle size (λ) increases the wall friction force and extra pressure drop Δp+, which in turn reduces the vesicle velocity U. Hydrodynamic interactions between vesicles in a periodic train are largely screened by the channel walls, in accordance with previous results for spheres and drops. The hydraulic resistance is compared across different cross sections, and a simple correction factor is proposed to unify the results. Nonlinear effects are observed when β - the ratio of membrane bending elasticity to viscous traction - is changed. The simulation results show excellent agreement with available experimental measurements as well as a previously reported ``small-gap theory'' valid for large values of λ. NSF CBET 1066263/1066334.

  16. Role of diuretics, β blockers, and statins in increasing the risk of diabetes in patients with impaired glucose tolerance: reanalysis of data from the NAVIGATOR study.

    PubMed

    Shen, Lan; Shah, Bimal R; Reyes, Eric M; Thomas, Laine; Wojdyla, Daniel; Diem, Peter; Leiter, Lawrence A; Charbonnel, Bernard; Mareev, Viacheslav; Horton, Edward S; Haffner, Steven M; Soska, Vladimir; Holman, Rury; Bethel, M Angelyn; Schaper, Frank; Sun, Jie-Lena; McMurray, John J V; Califf, Robert M; Krum, Henry

    2013-12-09

    To examine the degree to which use of β blockers, statins, and diuretics in patients with impaired glucose tolerance and other cardiovascular risk factors is associated with new onset diabetes. Reanalysis of data from the Nateglinide and Valsartan in Impaired Glucose Tolerance Outcomes Research (NAVIGATOR) trial. NAVIGATOR trial. Patients who at baseline (enrolment) were treatment naïve to β blockers (n=5640), diuretics (n=6346), statins (n=6146), and calcium channel blockers (n=6294). Use of calcium channel blocker was used as a metabolically neutral control. Development of new onset diabetes diagnosed by standard plasma glucose level in all participants and confirmed with glucose tolerance testing within 12 weeks after the increased glucose value was recorded. The relation between each treatment and new onset diabetes was evaluated using marginal structural models for causal inference, to account for time dependent confounding in treatment assignment. During the median five years of follow-up, β blockers were started in 915 (16.2%) patients, diuretics in 1316 (20.7%), statins in 1353 (22.0%), and calcium channel blockers in 1171 (18.6%). After adjusting for baseline characteristics and time varying confounders, diuretics and statins were both associated with an increased risk of new onset diabetes (hazard ratio 1.23, 95% confidence interval 1.06 to 1.44, and 1.32, 1.14 to 1.48, respectively), whereas β blockers and calcium channel blockers were not associated with new onset diabetes (1.10, 0.92 to 1.31, and 0.95, 0.79 to 1.13, respectively). Among people with impaired glucose tolerance and other cardiovascular risk factors and with serial glucose measurements, diuretics and statins were associated with an increased risk of new onset diabetes, whereas the effect of β blockers was non-significant. ClinicalTrials.gov NCT00097786.

  17. Role of diuretics, β blockers, and statins in increasing the risk of diabetes in patients with impaired glucose tolerance: reanalysis of data from the NAVIGATOR study

    PubMed Central

    Shen, Lan; Shah, Bimal R; Reyes, Eric M; Thomas, Laine; Wojdyla, Daniel; Diem, Peter; Leiter, Lawrence A; Charbonnel, Bernard; Mareev, Viacheslav; Horton, Edward S; Haffner, Steven M; Soska, Vladimir; Holman, Rury; Bethel, M Angelyn; Schaper, Frank; Sun, Jie-Lena; McMurray, John JV; Califf, Robert M

    2013-01-01

    Objective To examine the degree to which use of β blockers, statins, and diuretics in patients with impaired glucose tolerance and other cardiovascular risk factors is associated with new onset diabetes. Design Reanalysis of data from the Nateglinide and Valsartan in Impaired Glucose Tolerance Outcomes Research (NAVIGATOR) trial. Setting NAVIGATOR trial. Participants Patients who at baseline (enrolment) were treatment naïve to β blockers (n=5640), diuretics (n=6346), statins (n=6146), and calcium channel blockers (n=6294). Use of calcium channel blocker was used as a metabolically neutral control. Main outcome measures Development of new onset diabetes diagnosed by standard plasma glucose level in all participants and confirmed with glucose tolerance testing within 12 weeks after the increased glucose value was recorded. The relation between each treatment and new onset diabetes was evaluated using marginal structural models for causal inference, to account for time dependent confounding in treatment assignment. Results During the median five years of follow-up, β blockers were started in 915 (16.2%) patients, diuretics in 1316 (20.7%), statins in 1353 (22.0%), and calcium channel blockers in 1171 (18.6%). After adjusting for baseline characteristics and time varying confounders, diuretics and statins were both associated with an increased risk of new onset diabetes (hazard ratio 1.23, 95% confidence interval 1.06 to 1.44, and 1.32, 1.14 to 1.48, respectively), whereas β blockers and calcium channel blockers were not associated with new onset diabetes (1.10, 0.92 to 1.31, and 0.95, 0.79 to 1.13, respectively). Conclusions Among people with impaired glucose tolerance and other cardiovascular risk factors and with serial glucose measurements, diuretics and statins were associated with an increased risk of new onset diabetes, whereas the effect of β blockers was non-significant. Trial registration ClinicalTrials.gov NCT00097786. PMID:24322398

  18. Operation and Maintenance. 9-Foot Navigation Channel, Upper Mississippi River, Head of Navigation to Guttenberg, Iowa. Volume 1. Narrative.

    DTIC Science & Technology

    1974-08-01

    forest, along with wood nettle, which is by far the most common shrub layer vegetation, although neither is abundant in the forest proper. Vine form...poison ivy, Virginia creeper, wild grape, p" are common woody vines . The high unshaded edges of running sloughs in the forest areas often have thick...Mississippi River floodplain. 36 7.....a................ S -"’ 2.10 Beginning about 1 million years ago, the Upper Midwest entered what is commonly referred to

  19. Feasibility Report on Navigation Improvements for Mexico Beach Inlet, Mexico Beach, Florida.

    DTIC Science & Technology

    1989-03-01

    result from frontal passages in which rain generally lasts the duration of the storm. The area is subject to tropical hurricanes, particularly in late...the city had restored the channel to pre-hurricane conditions, Hurricane/ Tropical Storm Juan again shoaled the channel severely on 31 October 1985...general geology in the vicinity of Mexico Beach is coastal lowlands which has forested rolling hills in the interior and fine sand beaches along the coast

  20. The Effect of Ship Inherent Controllability on Piloted Performance: The Simulator Experiment

    DTIC Science & Technology

    1990-10-01

    planned analysis that would look for a dependence of the piloted maneuvers on the inherent controllability of the ships, the transit ccnditions and pilot...instructions were planned to sample the maneuvers needed in a narrow channel. Each run was initialized with the ship to the right of the channel...to Navigation Systems Design Manual for Restricted Waterways," (Smith et al., 1985). As of this writing this revision is planned for calendar year 1991

  1. RBS, TEM and SEM Characterization of Gold Nanoclusters in TiO2(110)

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

    Shutthanandan, V; Zhang, Yanwen; Wang, Chong M.

    2004-05-01

    Nucleation of gold nanoclusters in TiO2(110) single crystal using ion implantation and subsequent annealing were studied by Rutherford backscattering spectrometry /channeling (RBS/C), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Approximately 1000 Au2+/nm2 was implanted at room temperature in TiO2(110) substrates. TEM and SEM measurements revel that rounded nanoclusters were formed during the implantation. In contrast subsequent annealing in air for 10 hours at 1275 K promoted the formation of faceted (rectangular shaped) Au nano structures in TiO2. RBS channeling measurements further reveled that Au atoms randomly occupied in the host TiO2 lattice during the implantation. However, some ofmore » the gold atoms were moved into the Ti lattice position after annealing.« less

  2. User's Manual for LINER: FORTRAN Code for the Numerical Simulation of Plane Wave Propagation in a Lined Two-Dimensional Channel

    NASA Technical Reports Server (NTRS)

    Reichert, R, S.; Biringen, S.; Howard, J. E.

    1999-01-01

    LINER is a system of Fortran 77 codes which performs a 2D analysis of acoustic wave propagation and noise suppression in a rectangular channel with a continuous liner at the top wall. This new implementation is designed to streamline the usage of the several codes making up LINER, resulting in a useful design tool. Major input parameters are placed in two main data files, input.inc and nurn.prm. Output data appear in the form of ASCII files as well as a choice of GNUPLOT graphs. Section 2 briefly describes the physical model. Section 3 discusses the numerical methods; Section 4 gives a detailed account of program usage, including input formats and graphical options. A sample run is also provided. Finally, Section 5 briefly describes the individual program files.

  3. Flight tests of the 4D flight guidance display

    NASA Astrophysics Data System (ADS)

    Below, Christian; von Viebahn, Harro; Purpus, Matthias

    1997-06-01

    A perspective primary flight and a navigation display format were evaluated in a flying testbed. The flight tests comprised ILS- and standard approaches as well as low level operations utilizing the depiction of a spatial channel, and demonstrations of the inherent ground proximity warning function. In the cockpit of the VFW614, the left seat was equipped with a sidestick and a flat panel display, which showed both the 4D-display an the Navigation Display format. Airline and airforce pilots flew several missions each. Although most of the pilots criticizes that a typical flight director commanding the aircraft's attitude was missing, they could follow the channel precisely. However, some airline pilots stated a lack of vertical guidance information during the final approach. Leaving and re- entering the channel could be easily accomplished form any direction. In summary pilots' assessment of the display concept yielded an overall improvement of SA. In particular it was stated that displays are an appropriate means to avoid CFIT accidents. With the fist prototypes of 3D- graphics generators designed for avionics available the flight evaluation will continue including feasibility demonstrations of high-performance graphics for civil and military aircraft applications.

  4. Spacesuit Water Membrane Evaporator Development for Lunar Missions

    NASA Technical Reports Server (NTRS)

    Vogel, Matt R.; Peterson, Keith; Zapata, Felipe, III; Dillon, Paul; Trevino, Luis A.

    2008-01-01

    For future lunar extra-vehicular activities (EVA), one method under consideration for rejecting crew and electronics heat involves evaporating water through a hydrophobic, porous Teflon membrane. A Spacesuit Water Membrane Evaporator (SWME) prototype using the Teflon membrane was tested successfully by Ungar and Thomas (2001) with predicted performance matching test data well. The above referenced work laid the foundation for the design of the SWME development unit, which is being considered for service in the Constellation System Spacesuit Element (CSSE) Portable Life Support System (PLSS). Multiple PLSS SWME configurations were considered on the basis of thermal performance, mass, volume, and performance and manufacturing risk. All configurations were a variation of an alternating concentric water and vapor channel configuration or a stack of alternating rectangular water and vapor channels. Supporting thermal performance trades mapped maximum SWME heat rejection as a function of water channel thickness, vapor channel thickness, channel length, number of water channels, porosity of the membrane structural support, and backpressure valve throat area. Preliminary designs of each configuration were developed to determine total mass and volume as well as to understand manufacturing issues. Review of configurations led to the selection of a concentric annulus configuration that meets the requirements of 800 watts (W) of heat rejection. Detailed design of the SWME development unit will be followed by fabrication of a prototype test unit, with thermal testing expected to start in 2008.

  5. River enhancement in the Upper Mississippi River basin: Approaches based on river uses, alterations, and management agencies

    USGS Publications Warehouse

    O'Donnell, T. K.; Galat, D.L.

    2007-01-01

    The Upper Mississippi River is characterized by a series of locks and dams, shallow impoundments, and thousands of river channelization structures that facilitate commercial navigation between Minneapolis, Minnesota, and Cairo, Illinois. Agriculture and urban development over the past 200 years have degraded water quality and increased the rate of sediment and nutrient delivery to surface waters. River enhancement has become an important management tool employed to address causes and effects of surface water degradation and river modification in the Upper Mississippi River Basin. We report information on individual river enhancement projects and contrast project densities, goals, activities, monitoring, and cost between commercially non-navigated and navigated rivers (Non-navigated and Navigated Rivers, respectively). The total number of river enhancement projects collected during this effort was 62,108. Cost of all projects reporting spending between 1972 and 2006 was about US$1.6 billion. Water quality management was the most cited project goal within the basin. Other important goals in Navigated Rivers included in-stream habitat improvement and flow modification. Most projects collected for Non-navigated Rivers and their watersheds originated from the U.S. Department of Agriculture (USDA). The U.S. Army Corps of Engineers and the USDA were important sources for projects in Navigated Rivers. Collaborative efforts between agencies that implement projects in Non-navigated and Navigated Rivers may be needed to more effectively address river impairment. However, the current state of data sources tracking river enhancement projects deters efficient and broad-scale integration. ?? Journal compilation ?? 2007 Society for Ecological Restoration International.

  6. Navigable windows of the Northwest Passage

    NASA Astrophysics Data System (ADS)

    Liu, Xing-he; Ma, Long; Wang, Jia-yue; Wang, Ye; Wang, Li-na

    2017-09-01

    Artic sea ice loss trends support a greater potential for Arctic shipping. The information of sea ice conditions is important for utilizing Arctic passages. Based on the shipping routes given by ;Arctic Marine Shipping Assessment 2009 Report;, the navigable windows of these routes and the constituent legs were calculated by using sea ice concentration product data from 2006 to 2015, by which a comprehensive knowledge of the sea ice condition of the Northwest Passage was achieved. The results showed that Route 4 (Lancaster Sound - Barrow Strait - Prince Regent Inlet and Bellot Strait - Franklin Strait - Larsen Sound - Victoria Strait - Queen Maud Gulf - Dease Strait - Coronation Gulf - Dolphin and Union Strait - Amundsen Gulf) had the best navigable expectation, Route 2 (Parry Channel - M'Clure Strait) had the worst, and the critical legs affecting the navigation of Northwest Passage were Viscount Melville Sound, Franklin Strait, Victoria Strait, Bellot Strait, M'Clure Strait and Prince of Wales Strait. The shortest navigable period of the routes of Northwest Passage was up to 69 days. The methods used and the results of the study can help the selection and evaluation of Arctic commercial routes.

  7. Numerical investigation of thermal-hydraulic performance of channel with protrusions by turbulent cross flow jet

    NASA Astrophysics Data System (ADS)

    Sahu, M. K.; Pandey, K. M.; Chatterjee, S.

    2018-05-01

    In this two dimensional numerical investigation, small rectangular channel with right angled triangular protrusions in the bottom wall of test section is considered. A slot nozzle is placed at the middle of top wall of channel which impinges air normal to the protruded surface. A duct flow and nozzle flow combined to form cross flow which is investigated for heat transfer enhancement of protruded channel. The governing equations for continuity, momentum, energy along with SST k-ω turbulence model are solved with finite volume based Computational fluid dynamics code ANSYS FLUENT 14.0. The range of duct Reynolds number considered for this analysis is 8357 to 51760. The ratios of pitch of protrusion to height of duct considered are 0.5, 0.64 and 0.82. The ratios of height of protrusion to height of duct considered are 0.14, 0.23 and 0.29. The effect of duct Reynolds number, pitch and height of protrusion on thermal-hydraulic performance is studied under cross flow condition. It is found that heat transfer rate is more at relatively larger pitch and small pressure drop is found in case of low height of protrusion.

  8. Mixing in the shear superposition micromixer: three-dimensional analysis.

    PubMed

    Bottausci, Frederic; Mezić, Igor; Meinhart, Carl D; Cardonne, Caroline

    2004-05-15

    In this paper, we analyse mixing in an active chaotic advection micromixer. The micromixer consists of a main rectangular channel and three cross-stream secondary channels that provide ability for time-dependent actuation of the flow stream in the direction orthogonal to the main stream. Three-dimensional motion in the mixer is studied. Numerical simulations and modelling of the flow are pursued in order to understand the experiments. It is shown that for some values of parameters a simple model can be derived that clearly represents the flow nature. Particle image velocimetry measurements of the flow are compared with numerical simulations and the analytical model. A measure for mixing, the mixing variance coefficient (MVC), is analysed. It is shown that mixing is substantially improved with multiple side channels with oscillatory flows, whose frequencies are increasing downstream. The optimization of MVC results for single side-channel mixing is presented. It is shown that dependence of MVC on frequency is not monotone, and a local minimum is found. Residence time distributions derived from the analytical model are analysed. It is shown that, while the average Lagrangian velocity profile is flattened over the steady flow, Taylor-dispersion effects are still present for the current micromixer configuration.

  9. Nonlinear stability analysis of Darcy’s flow with viscous heating

    PubMed Central

    Alves, Leonardo S. de B.; Barletta, Antonio

    2016-01-01

    The nonlinear stability of a rectangular porous channel saturated by a fluid is here investigated. The aspect ratio of the channel is assumed to be variable. The channel walls are considered impermeable and adiabatic except for the horizontal top which is assumed to be isothermal. The viscous dissipation is acting inside the channel as internal heat generator. A basic throughflow is imposed, and the nonlinear convective stability is investigated by means of the generalized integral transform technique. The neutral stability curve is compared with the one obtained by the linear stability analysis already present in the literature. The growth rate analysis of different unstable modes is performed. The Nusselt number is investigated for several supercritical configurations in order to better understand how the system behaves when conditions far away from neutral stability are considered. The patterns of the neutrally stable convective cells are also reported. Nonlinear simulations support the results obtained by means of the linear stability analysis, confirming that viscous dissipation alone is indeed capable of inducing mixed convection. Low Gebhart or high Péclet numbers lead to a transient overheating of the originally motionless fluid before it settles in its convective steady state. PMID:27279772

  10. Optimizing the longitudinal and transverse electroosmotic pumping in a rectangular channel with horizontal baffle plates

    NASA Astrophysics Data System (ADS)

    Lai, Anison K. R.; Chang, Chien-Cheng; Wang, Chang-Yi

    2018-04-01

    This paper presents a continued study to our previous work on electroosmotic (EO) flow in a channel with vertical baffle plates by further investigating EO flow through an array of baffle plates arranged in parallel to the channel walls. The flow may be driven either in the direction along or in the direction transverse to the plates, thus distinguishing the longitudinal EO pumping (LEOP) and the transverse EO pumping (TEOP). In both types of EO pumping, it is more interesting to examine the cases when the baffle plates develop a higher zeta potential (denoted by α) than that on the channel walls (β). This semi-analytical study enables us to compare between LEOP and TEOP in the pumping efficiency under similar conditions. The TEOP case is more difficult to solve due to the higher order governing partial differential equations caused by the induced non-uniform pressure gradient distribution. In particular, we examine how the EO pumping rates deviate from those predicted by the Helmholtz-Smoluchowski velocity and illustrate the general trend of optimizing the EO pumping rates with respect to the physical and geometric parameters involved.

  11. View of movable span and point truss (to right), from ...

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

    View of movable span and point truss (to right), from navy land, looking west, showing bridge in context of navigational channel. - Naval Supply Annex Stockton, Daggett Road Bridge, Daggett Road traversing Burns Cut Off, Stockton, San Joaquin County, CA

  12. Improving Navigation information for the Rotterdam Harbour access through a 3D Model and HF radar

    NASA Astrophysics Data System (ADS)

    Schroevers, Marinus

    2015-04-01

    The Port of Rotterdam is one of the largest harbours in the world and a gateway to Europe. For the access to Rotterdam harbour, information on hydrodynamic and meteorological conditions is of vital importance for safe and swift navigation. This information focuses on the deep navigation channel in the shallow foreshore, which accommodates large seagoing vessels. Due to a large seaward extension of the Port of Rotterdam area in 2011, current patterns have changed. A re-evaluation of the information needed, showed a need for an improved accuracy of the cross channel currents and swell, and an extended forecast horizon. To obtain this, new information system was designed based on a three dimensional hydrodynamic model which produces a 72 hour forecast. Furthermore, the system will assimilate HF radars surface current to optimize the short term forecast. The project has started in 2013 by specifying data needed from the HF radar. At the same time (temporary) buoys were deployed to monitor vertical current profiles. The HF radar will be operational in July 2015, while the model development starts beginning 2015. A pre operational version of the system is presently planned for the end of 2016. A full operational version which assimilates the HF radar data is planned for 2017.

  13. Heat transfer in thin, compact heat exchangers with circular, rectangular, or pin-fin flow passages

    NASA Technical Reports Server (NTRS)

    Olson, D. A.

    1992-01-01

    Heat transfer and pressure drop have been measured of three thin, compact heat exchangers in helium gas at 3.5 MPa and higher, with Reynolds numbers of 450 to 36,000. The flow geometries for the three heat exchanger specimens were: circular tube, rectangular channel, and staggered pin fin with tapered pins. The specimens were heated radiatively at heat fluxes up to 77 W/sq cm. Correlations were developed for the isothermal friction factor as a function of Reynolds number, and for the Nusselt number as a function of Reynolds number and the ratio of wall temperature to fluid temperature. The specimen with the pin fin internal geometry had significantly better heat transfer than the other specimens, but it also had higher pressure drop. For certain conditions of helium flow and heating, the temperature more than doubled from the inlet to the outlet of the specimens, producing large changes in gas velocity, density, viscosity, and thermal conductivity. These changes in properties did not affect the correlations for friction factor and Nusselt number in turbulent flow.

  14. Boiling heat transfer during flow of distilled water in an asymmetrically heated rectangular minichannel

    NASA Astrophysics Data System (ADS)

    Strąk, Kinga; Piasecka, Magdalena

    This paper discusses test results concerning flow boiling heat transfer in a minichannel 1.7 mm in depth, 16 mm in width and 180 mm in length. The essential part of the experimental stand was a vertically oriented rectangular minichannel, which was heated asymmetrically with a plate made of Haynes-230 alloy. Distilled water was used as the cooling fluid. Changes in the temperature on the outer side of the heated plate in the central, axially symmetric part of the channel were measured using infrared thermography. Simultaneously, the other side of the heated plate in contact with the fluid was observed through a glass pane to identify the two-phase flow patterns. The one-dimensional model used for the heat transfer analysis took into account the heat flow direction, which was perpendicular to the direction of the fluid flow in the minichannel. The study involved determining local values of the heat transfer coefficient and generating boiling curves. The data for water were compared with the findings reported for the FC-72 fluid.

  15. Quasi-D-shaped optical fiber plasmonic refractive index sensor

    NASA Astrophysics Data System (ADS)

    An, Guowen; Li, Shuguang; Wang, Haiyang; Zhang, Xuenan; Yan, Xin

    2018-03-01

    A quasi-D-shaped photonic crystal fiber plasmonic sensor with a rectangular lattice is proposed by using Au as a plasmonic layer and graphene to enhance the sensing performance. By moving the core to the edge of the fiber, a shorter polishing depth is achieved, which makes the fiber proposed have a greater mechanical strength than other common D-shaped fibers. Benefiting from the natural advantage of the rectangular lattice, the dual sensing channels make the proposed sensor show a maximum wavelength interrogation sensitivity of 3877 nm/RIU with the dynamic refractive index range from 1.33 to 1.42 and a maximum amplitude sensitivity of 1236 RIU-1 with the analyte RI = 1.41 in the visible region. The corresponding resolutions are 2.58 × 10-5 and 8.1 × 10-6 with the methods of the wavelength interrogation method and amplitude- or phase-based method. These advantages make the proposed sensor a competitive candidate for biosensing in the field of refractive index detection, such as water quality analysis, clinical medicine detection, and pharmaceutical testing.

  16. Development of a Crosslink Channel Simulator

    NASA Technical Reports Server (NTRS)

    Hunt, Chris; Smith, Carl; Burns, Rich

    2004-01-01

    Distributed Spacecraft missions are an integral part of current and future plans for NASA and other space agencies. Many of these multi-vehicle missions involve utilizing the array of spacecraft as a single, instrument requiring communication via crosslinks to achieve mission goals. NASA s Goddard Space Flight Center (GSFC) is developing the Formation Flying Test Bed (FFTB) to provide a hardware-in-the-loop simulation environment to support mission concept development and system trades with a primary focus on Guidance, Navigation, and Control (GN&C) challenges associated with spacecraft flying. The goal of the FFTB is to reduce mission risk by assisting in mission planning and analysis, provide a technology development platform that allows algorithms to be developed for mission functions such as precision formation navigation and control and time synchronization. The FFTB will provide a medium in which the various crosslink transponders being used in multi-vehicle missions can be integrated for development and test; an integral part of the FFTB is the Crosslink Channel Simulator (CCS). The CCS is placed into the communications channel between the crosslinks under test, and is used to simulate on-mission effects to the communications channel such as vehicle maneuvers, relative vehicle motion, or antenna misalignment. The CCS is based on the Starlight software programmable platform developed at General Dynamics Decision Systems and provides the CCS with the ability to be modified on the fly to adapt to new crosslink formats or mission parameters. This paper briefly describes the Formation Flying Test Bed and its potential uses. It then provides details on the current and future development of the Crosslink Channel Simulator and its capabilities.

  17. Mitigation of Shore Damage Attributed to the Federal Navigation Structures at Ludington Harbor, Michigan.

    DTIC Science & Technology

    1975-12-01

    In Block 20, If different from Report) IS. SUPPLEMENTARY NOTES 19. KEY WORDS (Continu, on reverse aide If necesary and Identify by block number) 20...AST’R ACT (Cndbie m reverse ohb N n..e~ww and ideti fy by block number) DD JA 473 EDITION OF I NOV GS 15 OBSOLETE 4~ -i ~SECURITY CLASSIFICATION OF...and Harbor Act of 1867 provided Federal assistance for improving the harbor and channel. Revetments and channel piers were constructed under this Act

  18. Locomotion of Paramecium in patterned environments

    NASA Astrophysics Data System (ADS)

    Park, Eun-Jik; Eddins, Aja; Kim, Junil; Yang, Sung; Jana, Saikat; Jung, Sunghwan

    2011-10-01

    Ciliary organisms like Paramecium Multimicronucleatum locomote by synchronized beating of cilia that produce metachronal waves over their body. In their natural environments they navigate through a variety of environments especially surfaces with different topology. We study the effects of wavy surfaces patterned on the PDMS channels on the locomotive abilities of Paramecium by characterizing different quantities like velocity amplitude and wavelength of the trajectories traced. We compare this result with the swimming characteristics in straight channels and draw conclusions about the effects of various patterned surfaces.

  19. Cultural Resources and Geomorphological Reconnaissance of the McClellan-Kerr, Arkansas River Navigation System. Pools 1 through 9

    DTIC Science & Technology

    1989-01-01

    either the Petit Jean or Maumelle reaches as it flows out of the Ouachita Mountains into the unconsolidated sediments of the Mississippi River valley...small breaks, each depositing its load of coarser sediments in its own way. This results in sharply contrasting lenses of very small dimensions and...reflected in the channel size which decreases with increasing amounts of sediment deposited in the channel. Additionally, the amount of sediment deposited

  20. Coastal Inlets Research Program

    DTIC Science & Technology

    2012-01-01

    Basin Vce, VDe ,VEe,VFe,Vye ,VOe 0.3 Coastal and Hydraulics Laboratory 4  Conduct R&D to reduce O&M costs at coastal navigation projects  Include...200,000 m3 VOe=1,000,000,000 m3 Offshore Ebb Shoal Channel Flood Shoal Bay Deposition Basin Vce, VDe ,VEe,VFe,Vye ,VOe 0.3 …seamless connecting...m3 VOe=1,000,000,000 m3 Offshore Ebb Shoal Channel Flood Shoal Bay Deposition Basin Vce, VDe ,VEe,VFe,Vye ,VOe 0.3 Existing Data Models and

  1. Maintaining safe, efficient and sustainable intermodal transport through the Port of Portland.

    DOT National Transportation Integrated Search

    2011-10-01

    "About $15 billion of freight passes annually through the Lower Columbia River (LCR) navigation channel to reach Portland and Vancouver, : where most of it connects with land transport. This commerce plays a vital role in sustaining the regional econ...

  2. Submarine harbor navigation using image data

    NASA Astrophysics Data System (ADS)

    Stubberud, Stephen C.; Kramer, Kathleen A.

    2017-01-01

    The process of ingress and egress of a United States Navy submarine is a human-intensive process that takes numerous individuals to monitor locations and for hazards. Sailors pass vocal information to bridge where it is processed manually. There is interest in using video imaging of the periscope view to more automatically provide navigation within harbors and other points of ingress and egress. In this paper, video-based navigation is examined as a target-tracking problem. While some image-processing methods claim to provide range information, the moving platform problem and weather concerns, such as fog, reduce the effectiveness of these range estimates. The video-navigation problem then becomes an angle-only tracking problem. Angle-only tracking is known to be fraught with difficulties, due to the fact that the unobservable space is not the null space. When using a Kalman filter estimator to perform the tracking, significant errors arise which could endanger the submarine. This work analyzes the performance of the Kalman filter when angle-only measurements are used to provide the target tracks. This paper addresses estimation unobservability and the minimal set of requirements that are needed to address it in this complex but real-world problem. Three major issues are addressed: the knowledge of navigation beacons/landmarks' locations, the minimal number of these beacons needed to maintain the course, and update rates of the angles of the landmarks as the periscope rotates and landmarks become obscured due to blockage and weather. The goal is to address the problem of navigation to and from the docks, while maintaining the traversing of the harbor channel based on maritime rules relying solely on the image-based data. The minimal number of beacons will be considered. For this effort, the image correlation from frame to frame is assumed to be achieved perfectly. Variation in the update rates and the dropping of data due to rotation and obscuration is considered. The analysis will be based on a simple straight-line channel harbor entry to the dock, similar to a submarine entering the submarine port in San Diego.

  3. Use of Cusp Catastrophe for Risk Analysis of Navigational Environment: A Case Study of Three Gorges Reservoir Area

    PubMed Central

    Hao, Guozhu

    2016-01-01

    A water traffic system is a huge, nonlinear, complex system, and its stability is affected by various factors. Water traffic accidents can be considered to be a kind of mutation of a water traffic system caused by the coupling of multiple navigational environment factors. In this study, the catastrophe theory, principal component analysis (PCA), and multivariate statistics are integrated to establish a situation recognition model for a navigational environment with the aim of performing a quantitative analysis of the situation of this environment via the extraction and classification of its key influencing factors; in this model, the natural environment and traffic environment are considered to be two control variables. The Three Gorges Reservoir area of the Yangtze River is considered as an example, and six critical factors, i.e., the visibility, wind, current velocity, route intersection, channel dimension, and traffic flow, are classified into two principal components: the natural environment and traffic environment. These two components are assumed to have the greatest influence on the navigation risk. Then, the cusp catastrophe model is employed to identify the safety situation of the regional navigational environment in the Three Gorges Reservoir area. The simulation results indicate that the situation of the navigational environment of this area is gradually worsening from downstream to upstream. PMID:27391057

  4. Use of Cusp Catastrophe for Risk Analysis of Navigational Environment: A Case Study of Three Gorges Reservoir Area.

    PubMed

    Jiang, Dan; Hao, Guozhu; Huang, Liwen; Zhang, Dan

    2016-01-01

    A water traffic system is a huge, nonlinear, complex system, and its stability is affected by various factors. Water traffic accidents can be considered to be a kind of mutation of a water traffic system caused by the coupling of multiple navigational environment factors. In this study, the catastrophe theory, principal component analysis (PCA), and multivariate statistics are integrated to establish a situation recognition model for a navigational environment with the aim of performing a quantitative analysis of the situation of this environment via the extraction and classification of its key influencing factors; in this model, the natural environment and traffic environment are considered to be two control variables. The Three Gorges Reservoir area of the Yangtze River is considered as an example, and six critical factors, i.e., the visibility, wind, current velocity, route intersection, channel dimension, and traffic flow, are classified into two principal components: the natural environment and traffic environment. These two components are assumed to have the greatest influence on the navigation risk. Then, the cusp catastrophe model is employed to identify the safety situation of the regional navigational environment in the Three Gorges Reservoir area. The simulation results indicate that the situation of the navigational environment of this area is gradually worsening from downstream to upstream.

  5. Integrated Optical Interferometers with Micromachined Diaphragms for Pressure Sensing

    NASA Technical Reports Server (NTRS)

    DeBrabander, Gregory N.; Boyd, Joseph T.

    1996-01-01

    Optical pressure sensors have been fabricated which use an integrated optical channel waveguide that is part of an interferometer to measure the pressure-induced strain in a micromachined silicon diaphragm. A silicon substrate is etched from the back of the wafer leaving a rectangular diaphragm. On the opposite side of the wafer, ring resonator and Mach-Zehnder interferometers are formed with optical channel waveguides made from a low pressure chemical vapor deposited film of silicon oxynitride. The interferometer's phase is altered by pressure-induced stress in a channel segment positioned over the long edge of the diaphragm. The phase change in the ring resonator is monitored using a link-insensitive swept frequency laser diode, while in the Mach-Zehnder it is determined using a broad band super luminescent diode with subsequent wavelength separation. The ring resonator was found to be highly temperature sensitive, while the Mach-Zehnder, which had a smaller optical path length difference, was proportionally less so. The quasi-TM mode was more sensitive to pressure, in accord with calculations. Waveguide and sensor theory, sensitivity calculations, a fabrication sequence, and experimental results are presented.

  6. Focusing and alignment of erythrocytes in a viscoelastic medium

    NASA Astrophysics Data System (ADS)

    Go, Taesik; Byeon, Hyeokjun; Lee, Sang Joon

    2017-01-01

    Viscoelastic fluid flow-induced cross-streamline migration has recently received considerable attention because this process provides simple focusing and alignment over a wide range of flow rates. The lateral migration of particles depends on the channel geometry and physicochemical properties of particles. In this study, digital in-line holographic microscopy (DIHM) is employed to investigate the lateral migration of human erythrocytes induced by viscoelastic fluid flow in a rectangular microchannel. DIHM provides 3D spatial distributions of particles and information on particle orientation in the microchannel. The elastic forces generated in the pressure-driven flows of a viscoelastic fluid push suspended particles away from the walls and enforce erythrocytes to have a fixed orientation. Blood cell deformability influences the lateral focusing and fixed orientation in the microchannel. Different from rigid spheres and hardened erythrocytes, deformable normal erythrocytes disperse from the channel center plane, as the flow rate increases. Furthermore, normal erythrocytes have a higher angle of inclination than hardened erythrocytes in the region near the side-walls of the channel. These results may guide the label-free diagnosis of hematological diseases caused by abnormal erythrocyte deformability.

  7. Active phase locking of thirty fiber channels using multilevel phase dithering method

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

    Huang, Zhimeng; Luo, Yongquan, E-mail: yongquan-l@sina.com; Liu, Cangli

    2016-03-15

    An active phase locking of a large-scale fiber array with thirty channels has been demonstrated experimentally. In the experiment, the first group of thirty phase controllers is used to compensate the phase noises between the elements and the second group of thirty phase modulators is used to impose additional phase disturbances to mimic the phase noises in the high power fiber amplifiers. A multi-level phase dithering algorithm using dual-level rectangular-wave phase modulation and time division multiplexing can achieve the same phase control as single/multi-frequency dithering technique, but without coherent demodulation circuit. The phase locking efficiency of 30 fiber channels ismore » achieved about 98.68%, 97.82%, and 96.50% with no additional phase distortion, modulated phase distortion I (±1 rad), and phase distortion II (±2 rad), corresponding to the phase error of λ/54, λ/43, and λ/34 rms. The contrast of the coherent combined beam profile is about 89%. Experimental results reveal that the multi-level phase dithering technique has great potential in scaling to a large number of laser beams.« less

  8. 18 CFR 708.1 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 18 Conservation of Power and Water Resources 2 2011-04-01 2011-04-01 false Definitions. 708.1... BASIN COMMISSION: PUBLIC PARTICIPATION IN UPPER MISSISSIPPI RIVER SYSTEM MASTER PLAN § 708.1 Definitions... commercial navigation channels on the Mississippi River main stem north of Cairo, Illinois; the Minnesota...

  9. 18 CFR 708.1 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 2 2012-04-01 2012-04-01 false Definitions. 708.1... BASIN COMMISSION: PUBLIC PARTICIPATION IN UPPER MISSISSIPPI RIVER SYSTEM MASTER PLAN § 708.1 Definitions... commercial navigation channels on the Mississippi River main stem north of Cairo, Illinois; the Minnesota...

  10. 18 CFR 708.1 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Definitions. 708.1... BASIN COMMISSION: PUBLIC PARTICIPATION IN UPPER MISSISSIPPI RIVER SYSTEM MASTER PLAN § 708.1 Definitions... commercial navigation channels on the Mississippi River main stem north of Cairo, Illinois; the Minnesota...

  11. 18 CFR 708.1 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Definitions. 708.1... BASIN COMMISSION: PUBLIC PARTICIPATION IN UPPER MISSISSIPPI RIVER SYSTEM MASTER PLAN § 708.1 Definitions... commercial navigation channels on the Mississippi River main stem north of Cairo, Illinois; the Minnesota...

  12. Port sedimentation solutions for the Tennessee-Tombigbee Waterway in Mississippi.

    DOT National Transportation Integrated Search

    2004-01-08

    Sedimentation of the navigation channel and ports on the Tennessee-Tombigbee Waterway has averaged over 800,000 yd3 per year since completion of the Waterway. The standard solution for the past 17 years has been to dredge the accumulated sediment and...

  13. View of approach span and movable span, looking southeast from ...

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

    View of approach span and movable span, looking southeast from navy land. Note that navigational channel exists only on north side of movable span. - Naval Supply Annex Stockton, Daggett Road Bridge, Daggett Road traversing Burns Cut Off, Stockton, San Joaquin County, CA

  14. Environmental Enhancements and Navigation Infrastructure: A Study of Existing Practices, Innovative Ideas, Impediments, and Research Needs

    DTIC Science & Technology

    2011-07-01

    velocity/substrate Excavate back channels in river systems Piers & Wharves Design hard structures to facilitate better seaweed recruitment...allows vegetative colonization of areas beneath the structures P Design hard structures to facilitate better seaweed recruitment I Provide

  15. Gravity-driven, dry granular flows over a loose bed in stationary and homogeneous conditions

    NASA Astrophysics Data System (ADS)

    Meninno, Sabrina; Armanini, Aronne; Larcher, Michele

    2018-02-01

    Flows involving solid particulates have been widely studied in recent years, but their dynamics are still a complex issue to model because they strongly depend on the interaction with the boundary conditions. We report on laboratory investigations regarding homogeneous and steady flows of identical particles over a loose bed in a rectangular channel. Accurate measurements were carried out through imaging techniques to estimate profiles of the mean velocity, solid concentration, and granular temperature for a large set of flow rates and widths. Vertical and transversal structures observed in the flow change as interparticle interactions become more collisional, and they depend on the bottom over which the flow develops. The lateral confinement has a remarkable effect on the flow, especially for narrow channels compared with the grain size, and a hydraulic analogy is able to show how the walls influence the mechanisms of friction and energy dissipation.

  16. Fatigue properties of an 1421 aluminum alloy processed by ECAE

    NASA Astrophysics Data System (ADS)

    Mogucheva, A.; Kaibyshev, R.

    2010-07-01

    Fatigue properties and fatigue crack growth rate were examined in an Al-Mg-Li-Sc-Zr allow subjected to equal channel angular extrusion (ECAE) with rectangular shape of channels up to a total strain of ~4 at a temperature of 325°C followed by solution treatment with subsequent oil quenching with aging. After this processing the fraction recrystallized was ~80pct; the deformed microstructure remains essentially unchanged under solution treatment due to high density of Al3Sc coherent dispersoids playing a role of effective pinning agents. It was shown that the fatigue limit of this material attained a value of ~185 MPa. Thermomechanical processing provided a decrease in fatigue crack propagation growth rate and an increase in the stress intensity factor, K1c, in comparison with extruded bar. However, characteristics of crack propagation resistance did not attain values suitable for application of this alloy for critical aircraft components.

  17. Swimming of Paramecium in confined channels

    NASA Astrophysics Data System (ADS)

    Jung, Sunghwan

    2012-02-01

    Many living organisms in nature have developed a few different swimming modes, presumably derived from hydrodynamic advantage. Paramecium is a ciliated protozoan covered by thousands of cilia with a few nanometers in diameter and tens of micro-meters in length and is able to exhibit both ballistic and meandering motions. First, we characterize ballistic swimming behaviors of ciliated microorganisms in glass capillaries of different diameters and explain the trajectories they trace out. We develop a theoretical model of an undulating sheet with a pressure gradient and discuss how it affects the swimming speed. Secondly, investigation into meandering swimmings within rectangular PDMS channels of dimension smaller than Paramecium length. We find that Paramecium executes a body-bend (an elastic buckling) using the cilia while it meanders. By considering an elastic beam model, we estimate and show the universal profile of forces it exerts on the walls. Finally, we discuss a few other locomotion of Paramecium in other extreme environments like gel.

  18. ESS Smelting Technology

    NASA Astrophysics Data System (ADS)

    Erasmus, L. J.; Fourie, L. J.

    2017-02-01

    The envirosteel smelter is a rectangular furnace with a large free board volume and multiple channel inductors mounted below the hearth. The raw materials are charged against the back wall forming an inclined heap sloping toward the front long wall. The feed blend is spread in thin layers over the surface of the heap and is heated by exposure to radiation from the free board. Reducing conditions in the top layer of the heap permit gas-solid reduction. Metal, in the hearth of the furnace, flows into the channel inductor where it is heated. The heated metal flows back against the front long wall to under the heap. The bottom of the heap is continuously melted by energy transferred from the metal layer. The two off-gas ducts are located in the short end walls. The combustion air is heated to around 800°C by a furnace gas in an external heat exchanger.

  19. Micro-fabricated packed gas chromatography column based on laser etching technology.

    PubMed

    Sun, J H; Guan, F Y; Zhu, X F; Ning, Z W; Ma, T J; Liu, J H; Deng, T

    2016-01-15

    In this work, a micro packed gas chromatograph column integrated with a micro heater was fabricated by using laser etching technology (LET) for analyzing environmental gases. LET is a powerful tool to etch deep well-shaped channels on the glass wafer, and it is the most effective way to increase depth of channels. The fabricated packed GC column with a length of over 1.6m, to our best knowledge, which is the longest so far. In addition, the fabricated column with a rectangular cross section of 1.2mm (depth) × 0.6mm (width) has a large aspect ratio of 2:1. The results show that the fabricated packed column had a large sample capacity, achieved a separation efficiency of about 5800 plates/m and eluted highly symmetrical Gaussian peaks. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Pattern selection in an anisotropic Hele-Shaw cell

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

    McCloud, K.V.; Maher, J.V.

    1995-02-01

    The selection of steady-state viscous fingers has been measured in Hele-Shaw cells that are perturbed by having rectangular and square lattices etched on one of their plates. The strength of the perturbation was varied by varying the cell gap, and over a wide range of observable tip velocities this local perturbation was also made microscopic in the sense that the capillary length of the flow was large in comparison to the cell size of the underlying lattice. Above threshold the microscopic perturbation results in the selection of wider fingers than those selected in the unperturbed flow for all channel orientationsmore » in the experiment. All observed solutions are symmetric, centered in the channel, and have the relation between tip curvature and finger width expected of members of the Saffman-Taylor family of solutions. Selected solutions narrow again at tip velocities where the perturbations can no longer be considered microscopic.« less

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