Detection, location, and characterization of hydroacoustic signals using seafloor cable networks offshore Japan (Invited)

NASA Astrophysics Data System (ADS)

Sugioka, H.; Suyehiro, K.; Shinohara, M.

2009-12-01

The hydroacoustic monitoring by the International Monitoring System (IMS) for Comprehensive Nuclear-Test-Treaty (CTBT) verification system utilize hydrophone stations and seismic stations called T-phase stations for worldwide detection. Some signals of natural origin include those from earthquakes, submarine volcanic eruptions, or whale calls. Among artificial sources there are non-nuclear explosions and air-gun shots. It is important for IMS system to detect and locate hydroacoustic events with sufficient accuracy and correctly characterize the signals and identify the source. As there are a number of seafloor cable networks operated offshore Japanese islands basically facing the Pacific Ocean for monitoring regional seismicity, the data from these stations (pressures, hydrophones and seismic sensors) may be utilized to verify and increase the capability of the IMS. We use these data to compare some selected event parameters with those by Pacific in the time period of 2004-present. These anomalous examples and also dynamite shots used for seismic crustal structure studies and other natural sources will be presented in order to help improve the IMS verification capabilities for detection, location and characterization of anomalous signals. The seafloor cable networks composed of three hydrophones and six seismometers and a temporal dense seismic array detected and located hydroacoustic events offshore Japanese island on 12th of March in 2008, which had been reported by the IMS. We detected not only the reverberated hydroacoustic waves between the sea surface and the sea bottom but also the seismic waves going through the crust associated with the events. The determined source of the seismic waves is almost coincident with the one of hydroacoustic waves, suggesting that the seismic waves are converted very close to the origin of the hydroacoustic source. We also detected very similar signals on 16th of March in 2009 to the ones associated with the event of 12th of

Wind-tunnel blockage and actuation systems test of a two-dimensional scramjet inlet unstart model at Mach 6

NASA Technical Reports Server (NTRS)

Holland, Scott D.

1994-01-01

The present study examines the wind-tunnel blockage and actuation systems effectiveness in starting and forcibly unstarting a two-dimensional scramjet inlet in the NASA Langley 20-Inch Mach 6 Tunnel. The intent of the overall test program is to study (both experimentally and computationally) the dynamics of the inlet unstart; however, prior to the design and fabrication of an expensive, instrumented wind-tunnel model, it was deemed necessary first to examine potential wind-tunnel blockage issues related to model sizing and to examine the adequacy of the actuation systems in accomplishing the start and unstart. The model is equipped with both a moveable cowl and aft plug. Windows in the inlet sidewalls allow limited optical access to the internal shock structure; schlieren video was used to identify inlet start and unstart. A chronology of each actuation sequence is provided in tabular form along with still frames from the schlieren video. A pitot probe monitored the freestream conditions throughout the start/unstart process to determine if there was a blockage effect due to the model start or unstart. Because the purpose of this report is to make the phase I (blockage and actuation systems) data rapidly available to the community, the data is presented largely without analysis of the internal shock interactions or the unstart process. This series of tests indicated that the model was appropriately sized for this facility and identified operability limits required first to allow the inlet to start and second to force the unstart.

Comparison between hydroacoustical and terrestrial evidence of glacially induced faulting, Lake Voxsjön, central Sweden

NASA Astrophysics Data System (ADS)

Smith, Colby A.; Nyberg, Johan; Bergman, Björn

2018-01-01

The recent availability of a terrestrial high-resolution digital elevation model in Sweden has led to the discovery of previously unknown scarps believed to be associated with bedrock faults that ruptured to the surface during the Holocene. Field investigations, however, are required to confirm these findings and determine the timing of post-glacial seismicity. Here, we present results from a unique hybrid approach, where hydroacoustical data from the sediments of Lake Voxsjön are compared to stratigraphic and geomorphologic records from nearby terrestrial settings. The hydroacoustical data are largely consistent with the terrestrial data indicating a single fault rupture shortly after deglaciation, which occurred about 11,000-10,500 cal BP.

An Experimental Evaluation of Blockage Corrections for Current Turbines

NASA Astrophysics Data System (ADS)

Ross, Hannah; Polagye, Brian

2017-11-01

Flow confinement has been shown to significantly alter the performance of turbines that extract power from water currents. These performance effects are related to the degree of constraint, defined by the ratio of turbine projected area to channel cross-sectional area. This quantity is referred to as the blockage ratio. Because it is often desirable to adjust experimental observations in water channels to unconfined conditions, analytical corrections for both wind and current turbines have been derived. These are generally based on linear momentum actuator disk theory but have been applied to turbines without experimental validation. This work tests multiple blockage corrections on performance and thrust data from a cross-flow turbine and porous plates (experimental analogues to actuator disks) collected in laboratory flumes at blockage ratios ranging between 10 and 35%. To isolate the effects of blockage, the Reynolds number, Froude number, and submergence depth were held constant while the channel width was varied. Corrected performance data are compared to performance in a towing tank at a blockage ratio of less than 5%. In addition to examining the accuracy of each correction, underlying assumptions are assessed to determine why some corrections perform better than others. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. DGE-1256082 and the Naval Facilities Engineering Command (NAVFAC).

Multi-sensor investigation of the Sumatran Tsunami: observations and analysis of hydroacoustic, seismic, infrasonic, and tide gauge data

NASA Astrophysics Data System (ADS)

Bhattacharyya, J.; Pulli, J.; Gibson, R.; Upton, Z.

2005-05-01

We present an analysis of the acoustic signals from the December 26, 2004 Sumatra earthquakes, in conjunction with the seismic and tide gauge information from the event. The M9.0 mainshock and its aftershocks were recorded by a suite of seismic sensors around the globe, giving us information on its location and the source process. Recently installed sensor assets in the Indian Ocean have enabled us to study additional features of this significant event. Hydroacoustic signals were recorded by three hydrophone arrays, and the direction finding capability of these arrays allows us to examine the location, time and extent of the T-wave generation process. We detect a clear variation of the back-azimuth that is consistent with the spatial extent of the source rupture. Recordings from nearly co-located seismometers provide insights into the acoustic-to-seismic conversion process for T-waves at islands, along with the variation in signal characteristics with source size. Two separate infrasound arrays detect the atmospheric signals generated by the event, along with additional observations of the seismic surface wave and the T-phase. We will present a comparison of the signals from the mainshock, as a function of location and size, with those from aftershocks and similar events in the nearby region. Our acoustic observations compare favorably with model predictions of wave propagation in the region. For the hydroacoustic data, the azimuth, arrival time, and signal blockage characteristics, from three separate arrays, associate the onset of the signal with the mainshock and with a time extent consistent with the rupture propagation. Our analysis of the T-phase travel times suggests that the seismic-to-acoustic conversion occurs more than 100 km from the epicenter. The infrasound signal's arrival time and signal duration are consistent with both stratospheric and thermospheric propagation from a source region near the mainshock. We use the tide gauge data from stations

Re-establishment of the IMS Hydroacoustic Station HA04, Crozet Islands, France.

NASA Astrophysics Data System (ADS)

Haralabus, Georgios; Stanley, Jerry; Zampolli, Mario; Grenard, Patrick; Nielsen, Peter; Le Bras, Ronan; Brown, David; Bittner, Paulina; Wang, Haijun; Gore, Jane; Amir, Menachem; Bereza, Slava

2017-04-01

The incorporation of the hydroacoustic station HA04, Crozet Islands, France, into the International Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO) is a 17 year saga that had a happy ending on 29 December 2016. On that day, following a major engineering and logistical undertaking, the station was successfully installed. While still in its initial testing phase, HA04 sends continuously quality data at the International Data Centre (IDC), pending official certification and promotion to mainstream operational status. Similarly to most other cabled hydroacoustic stations in the IMS, HA04 is comprised of two triplets of moored hydrophones deployed on both sides of Possession Island (Crozet Islands) sending uninterrupted data to a shore facility via submarine fiber optic cables. The designed frequency pass-band is 1 - 100 Hz. Data are relayed to Vienna via a shore based satellite link in real time. According to CTBTO's standard requirements, the design life of HA04 is at least 20 years, maintenance-free for the underwater system. An outline of the main phases of this project, highlights from the installation operations and examples of received hydroacoustic signals associated with recent underwater seismic activity in the Indian Ocean as well as vocalizations from marine mammals acquired by the new HA04 are presented here. HA04 is scheduled to be fully integrated into the operational platform of IDC in the next six months, which will enable registered researchers to access archived monitoring data and processing software, or via the National Data Centres (NDCs).

Hydroacoustic Estimates of Fish Density Distributions in Cougar Reservoir, 2011

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

Ploskey, Gene R.; Zimmerman, Shon A.; Hennen, Matthew J.

2012-09-01

Day and night mobile hydroacoustic surveys were conducted once each month from April through December 2011 to quantify the horizontal and vertical distributions of fish throughout Cougar Reservoir, Lane County, Oregon.

Estimation of tunnel blockage from wall pressure signatures: A review and data correlation

NASA Technical Reports Server (NTRS)

Hackett, J. E.; Wilsden, D. J.; Lilley, D. E.

1979-01-01

A method is described for estimating low speed wind tunnel blockage, including model volume, bubble separation and viscous wake effects. A tunnel-centerline, source/sink distribution is derived from measured wall pressure signatures using fast algorithms to solve the inverse problem in three dimensions. Blockage may then be computed throughout the test volume. Correlations using scaled models or tests in two tunnels were made in all cases. In many cases model reference area exceeded 10% of the tunnel cross-sectional area. Good correlations were obtained regarding model surface pressures, lift drag and pitching moment. It is shown that blockage-induced velocity variations across the test section are relatively unimportant but axial gradients should be considered when model size is determined.

Methods for monitoring hydroacoustic events using direct and reflected T waves in the Indian Ocean

NASA Astrophysics Data System (ADS)

Hanson, Jeffrey A.; Bowman, J. Roger

2006-02-01

The recent installation of permanent, three-element hydrophone arrays in the Indian Ocean offshore Diego Garcia and Cape Leeuwin, Australia, provides an opportunity to study hydroacoustic sources in more detail than previously possible. We developed and applied methods for coherent processing of the array data, for automated association of signals detected at more than one array, and for source location using only direct arrivals and using signals reflected from coastlines and other bathymetric features. During the 286-day study, 4725 hydroacoustic events were defined and located in the Indian and Southern oceans. Events fall into two classes: tectonic earthquakes and ice-related noise. The tectonic earthquakes consist of mid-ocean ridge, trench, and intraplate earthquakes. Mid-ocean ridge earthquakes are the most common tectonic events and often occur in clusters along transform offsets. Hydroacoustic signal levels for earthquakes in a standard catalog suggest that the hydroacoustic processing threshold for ridge events is one magnitude below the seismic network. Fewer earthquakes are observed along the Java Trench than expected because the large bathymetric relief of the source region complicates coupling between seismic and hydroacoustic signals, leading to divergent signal characteristics at different stations. We located 1843 events along the Antarctic coast resulting from various ice noises, most likely thermal fracturing and ice ridge forming events. Reflectors of signals from earthquakes are observed along coastlines, the mid-Indian Ocean and Ninety East ridges, and other bathymetric features. Reflected signals are used as synthetic stations to reduce location uncertainty and to enable event location with a single station.

Bacteriophage Can Prevent Encrustation and Blockage of Urinary Catheters by Proteus mirabilis

PubMed Central

Nzakizwanayo, Jonathan; Hanin, Aurélie; Alves, Diana R.; McCutcheon, Benjamin; Dedi, Cinzia; Salvage, Jonathan; Knox, Karen; Stewart, Bruce; Metcalfe, Anthony; Clark, Jason; Gilmore, Brendan F.; Gahan, Cormac G. M.; Jenkins, A. Toby A.

2015-01-01

Proteus mirabilis forms dense crystalline biofilms on catheter surfaces that occlude urine flow, leading to serious clinical complications in long-term catheterized patients, but there are presently no truly effective approaches to control catheter blockage by this organism. This study evaluated the potential for bacteriophage therapy to control P. mirabilis infection and prevent catheter blockage. Representative in vitro models of the catheterized urinary tract, simulating a complete closed drainage system as used in clinical practice, were employed to evaluate the performance of phage therapy in preventing blockage. Models mimicking either an established infection or early colonization of the catheterized urinary tract were treated with a single dose of a 3-phage cocktail, and the impact on time taken for catheters to block, as well as levels of crystalline biofilm formation, was measured. In models of established infection, phage treatment significantly increased time taken for catheters to block (∼3-fold) compared to untreated controls. However, in models simulating early-stage infection, phage treatment eradicated P. mirabilis and prevented blockage entirely. Analysis of catheters from models of established infection 10 h after phage application demonstrated that phage significantly reduced crystalline biofilm formation but did not significantly reduce the level of planktonic cells in the residual bladder urine. Taken together, these results show that bacteriophage constitute a promising strategy for the prevention of catheter blockage but that methods to deliver phage in sufficient numbers and within a key therapeutic window (early infection) will also be important to the successful application of phage to this problem. PMID:26711744

The Ascension Island hydroacoustic experiment: purpose, data set features and plans for future analysis

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

Harben, P E; Rock, D; Rodgers, A J

1999-07-23

Calibration of hydroacoustic and T-phase stations for Comprehensive Nuclear-Test-Ban Treaty (CTBT) monitoring will be an important element in establishing new operational stations and upgrading existing stations. Calibration of hydroacoustic stations is herein defined as precision location of the hydrophones and determination of the amplitude response from a known source energy. T-phase station calibration is herein defined as a determination of station site attenuation as a function of frequency, bearing, and distance for known impulsive energy sources in the ocean. To understand how to best conduct calibration experiments for both hydroacoustic and T-phase stations, an experiment was conducted in May, 1999more » at Ascension Island in the South Atlantic Ocean. The experiment made use of a British oceanographic research vessel and collected data that will be used for CTBT issues and for fundamental understanding of the Ascension Island volcanic edifice.« less

Local blockage of EMMPRIN impedes pressure ulcers healing in a rat model.

PubMed

Zhao, Xi-Lan; Luo, Xiao; Wang, Ze-Xin; Yang, Guo-Li; Liu, Ji-Zhong; Liu, Ya-Qiong; Li, Ming; Chen, Min; Xia, Yong-Mei; Liu, Jun-Jie; Qiu, Shu-Ping; Gong, Xiao-Qing

2015-01-01

Excessive extracellular matrix degradation caused by the hyperfunction of matrix metalloproteinases (MMPs) has been implicated in the failure of pressure ulcers healing. EMMPRIN, as a widely expressed protein, has emerged as an important regulator of MMP activity. We hypothesize that EMMPRIN affects the process of pressure ulcer healing by modulating MMP activity. In the rat pressure ulcer model, the expression of EMMPRIN in ulcers detected by Western blot was elevated compared with that observed in normal tissue. To investigate the role of EMMPRIN in regulating ulcer healing, specific antibodies against EMMPRIN were used via direct administration on the pressure ulcer. Local blockage of EMMPRIN resulted in a poor ulcer healing process compared with control ulcers, which was the opposite of our expectation. Furthermore, inhibiting EMMPRIN minimally impacted MMP activity. However, the collagen content in the pressure ulcer was reduced in the EMMPRIN treated group. Angiogenesis and the expression of angiogenic factors in pressure ulcers were also reduced by EMMPRIN local blockage. The results in the present study indicate a novel effect of EMMPRIN in the regulation of pressure ulcer healing by controlling the collagen contents and angiogenesis rather than MMPs activity.

Mach 4 free-jet tunnel starting experiments for a hypersonic research engine model causing high blockage

NASA Technical Reports Server (NTRS)

Carson, G. T., Jr.; Midden, R. E.

1976-01-01

Tests of a full scale hypersonic research engine (HRE) were conducted in the hypersonic tunnel facility at Mach numbers of 5, 6, and 7. Since the HRE would cause a rather high blockage (48.83 percent of the nozzle area), subscale tests were conducted in various available small wind tunnels prior to the full scale tests to study the effects of model blockage on tunnel starting. The results of the Mach 4 subscale tests which utilized a model system at 0.0952 scale which simulated the HRE in the test section of the tunnel are presented. A satisfactory tunnel starting could not be achieved by varying the free jet length or diffuser size nor by inserting the model into the test stream after tunnel starting. However, the installation of a shroud around the HRE model allowed the tunnel to start with the model preset in the tunnel at a tunnel stagnation pressure to atmospheric exit pressure ratio of 13.4. The simulation of the discharge of instrumentation cooling water and the addition of test hardware at the aft end of the HRE model did not have a significant effect on the tunnel starting.

A Ffowcs Williams and Hawkings formulation for hydroacoustic analysis of propeller sheet cavitation

NASA Astrophysics Data System (ADS)

Testa, C.; Ianniello, S.; Salvatore, F.

2018-01-01

A novel hydroacoustic formulation for the prediction of tonal noise emitted by marine propellers in presence of unsteady sheet cavitation, is presented. The approach is based on the standard Ffowcs Williams and Hawkings equation and the use of transpiration (velocity and acceleration) terms, accounting for the time evolution of the vapour cavity attached on the blade surface. Drawbacks and potentialities of the method are tested on a marine propeller operating in a nonhomogeneous onset flow, by exploiting the hydrodynamic data from a potential-based panel method equipped with a sheet cavitation model and comparing the noise predictions with those carried out by an alternative numerical approach, documented in literature. It is shown that the proposed formulation yields a one-to-one correlation between emitted noise and sheet cavitation dynamics, carrying out accurate predictions in terms of noise magnitude and directivity.

Effect of Ganoderma lucidum on pollen-induced biphasic nasal blockage in a guinea pig model of allergic rhinitis.

PubMed

Mizutani, Nobuaki; Nabe, Takeshi; Shimazu, Masaji; Yoshino, Shin; Kohno, Shigekatsu

2012-03-01

Ganoderma lucidum (GL), an oriental medical mushroom, has been used in Asia for the prevention and treatment of a variety of diseases. However, the effect of GL on allergic rhinitis has not been well defined. The current study describes the inhibitory effect of GL on the biphasic nasal blockage and nasal hyperresponsiveness induced by repeated antigen challenge in a guinea pig model of allergic rhinitis. Intranasally sensitized guinea pigs were repeatedly challenged by inhalation of Japanese cedar pollen once every week. Ganoderma lucidum was orally administered once daily for 8 weeks from the time before the first challenge. The treatment with GL dose-dependently inhibited the early and late phase nasal blockage at the fifth to ninth antigen challenges. Furthermore, nasal hyperresponsiveness to intranasally applied leukotriene D₄ on 2 days after the eighth antigen challenge was also inhibited by the treatment with GL. However, Cry j 1-specific IgE antibody production was not affected by the treatment. In conclusion, we demonstrated that the pollen-induced biphasic nasal blockage and nasal hyperresponsiveness were suppressed by the daily treatment with GL in the guinea pig model of allergic rhinitis. These results suggest that GL may be a useful therapeutic drug for treating patients with allergic rhinitis. Copyright © 2011 John Wiley & Sons, Ltd.

Transcription blockage by homopurine DNA sequences: role of sequence composition and single-strand breaks

PubMed Central

Belotserkovskii, Boris P.; Neil, Alexander J.; Saleh, Syed Shayon; Shin, Jane Hae Soo; Mirkin, Sergei M.; Hanawalt, Philip C.

2013-01-01

The ability of DNA to adopt non-canonical structures can affect transcription and has broad implications for genome functioning. We have recently reported that guanine-rich (G-rich) homopurine-homopyrimidine sequences cause significant blockage of transcription in vitro in a strictly orientation-dependent manner: when the G-rich strand serves as the non-template strand [Belotserkovskii et al. (2010) Mechanisms and implications of transcription blockage by guanine-rich DNA sequences., Proc. Natl Acad. Sci. USA, 107, 12816–12821]. We have now systematically studied the effect of the sequence composition and single-stranded breaks on this blockage. Although substitution of guanine by any other base reduced the blockage, cytosine and thymine reduced the blockage more significantly than adenine substitutions, affirming the importance of both G-richness and the homopurine-homopyrimidine character of the sequence for this effect. A single-strand break in the non-template strand adjacent to the G-rich stretch dramatically increased the blockage. Breaks in the non-template strand result in much weaker blockage signals extending downstream from the break even in the absence of the G-rich stretch. Our combined data support the notion that transcription blockage at homopurine-homopyrimidine sequences is caused by R-loop formation. PMID:23275544

Size-Based Hydroacoustic Measures of Within-Season Fish Abundance in a Boreal Freshwater Ecosystem

PubMed Central

Pollom, Riley A.; Rose, George A.

2015-01-01

Eleven sequential size-based hydroacoustic surveys conducted with a 200 kHz split-beam transducer during the summers of 2011 and 2012 were used to quantify seasonal declines in fish abundance in a boreal reservoir in Manitoba, Canada. Fish densities were sufficiently low to enable single target resolution and tracking. Target strengths converted to log2-based size-classes indicated that smaller fish were consistently more abundant than larger fish by a factor of approximately 3 for each halving of length. For all size classes, in both years, abundance (natural log) declined linearly over the summer at rates that varied from -0.067.day-1 for the smallest fish to -0.016.day-1 for the largest (R2 = 0.24–0.97). Inter-annual comparisons of size-based abundance suggested that for larger fish (>16 cm), mean winter decline rates were an order of magnitude lower (-0.001.day-1) and overall survival higher (71%) than in the main summer fishing season (mean loss rate -0.038.day-1; survival 33%). We conclude that size-based acoustic survey methods have the potential to assess within-season fish abundance dynamics, and may prove useful in long-term monitoring of productivity and hence management of boreal aquatic ecosystems. PMID:25875467

Preliminary Results from an Hydroacoustic Experiment in the Indian Ocean

NASA Astrophysics Data System (ADS)

Royer, J.; Dziak, R. P.; Delatre, M.; Brachet, C.; Haxel, J. H.; Matsumoto, H.; Goslin, J.; Brandon, V.; Bohnenstiehl, D. R.; Guinet, C.; Samaran, F.

2008-12-01

We report initial results from a 14-month hydroacoustic experiment in the Indian Ocean conducted by CNRS/University of Brest and NOAA/Oregon State University. The objective was to monitor the low-level seismic activity associated with the three contrasting spreading ridges and deforming zones in the Indian Ocean. Three autonomous hydrophones, moored in the SOFAR channel, were deployed in October 2006 and recovered early 2008 by R/V Marion Dufresne, in the Madagascar Basin, and northeast and southwest of Amsterdam Island, complementing the two permanent hydroacoustic stations of the Comprehensive nuclear-Test-Ban Treaty Organization (CTBTO) located near Diego Garcia Island and off Cape Leeuwin. Our temporary network detected more than 2000 events. Inside the array, we located 592 events (compared to 49 in the NEIC earthquake catalog) with location errors less than 5 km and time error less than 2s. The hydrophone array detected on average 5 to 40 times more events per month than land-based networks. First-order observations indicate that hydroacoustic seismicity along the Southeast Indian ridge (SEIR) occurs predominantly along the transform faults. The Southwest Indian Ridge exhibits some periodicity in earthquake activity between adjacent ridge segments. Two large tectonic/volcanic earthquake swarms are observed along the Central Indian Ridge (near the triple junction) in September and December 2007. Moreover, many off ridge-axis events are also observed both south and north of the SEIR axis. Improved localization using the CTBTO records will help refine these preliminary results and further investigate extended volcanic sequences along the SEIR east of 80°E and other events outside of the temporary array. The records also display numerous vocalizations of baleen whales in the 20-40Hz bandwidth. The calls are attributed to fin whales, Antarctic blue whales and pygmy blue whales of Madagascar and Australian type. Their vocal activity is found to be highly seasonal

Formation of Hydro-acoustic Waves in Dissipative Coupled Weakly Compressible Fluids

NASA Astrophysics Data System (ADS)

Abdolali, A.; Kirby, J. T., Jr.; Bellotti, G.

2014-12-01

Recent advances in deep sea measurement technology provide an increasing opportunity to detect and interpret hydro-acoustic waves as a component in improved Tsunami Early Warning Systems (TEWS). For the idealized case of a homogeneous water column above a moving but otherwise rigid bottom (in terms of assessing acoustic wave interaction), the description of the infinite family of acoustic modes is characterized by local water depth at source area; i.e. the period of the first acoustic mode is given by four times the required time for sound to travel from the seabed to the surface. Spreading off from earthquake zone, the dominant spectrum is filtered and enriched by seamounts and barriers. This study focuses on the characteristics of hydro-acoustic waves generated by sudden sea bottom motion in a weakly compressible fluid coupled with an underlying sedimentary layer, where the added complexity of the sediment layer rheology leads to both the lowering of dominant spectral peaks and wave attenuation across the full spectrum. To overcome the computational difficulties of three-dimensional models, we derive a depth integrated equation valid for varying water depth and sediment thickness. Damping behavior of the two layered system is initially taken into account by introducing the viscosity of fluid-like sedimentary layer. We show that low frequency pressure waves which are precursor components of tsunamis contain information of seafloor motion.

An approximate inverse scattering technique for reconstructing blockage profiles in water pipelines using acoustic transients.

PubMed

Jing, Liwen; Li, Zhao; Wang, Wenjie; Dubey, Amartansh; Lee, Pedro; Meniconi, Silvia; Brunone, Bruno; Murch, Ross D

2018-05-01

An approximate inverse scattering technique is proposed for reconstructing cross-sectional area variation along water pipelines to deduce the size and position of blockages. The technique allows the reconstructed blockage profile to be written explicitly in terms of the measured acoustic reflectivity. It is based upon the Born approximation and provides good accuracy, low computational complexity, and insight into the reconstruction process. Numerical simulations and experimental results are provided for long pipelines with mild and severe blockages of different lengths. Good agreement is found between the inverse result and the actual pipe condition for mild blockages.

Optimal and adaptive methods of processing hydroacoustic signals (review)

NASA Astrophysics Data System (ADS)

Malyshkin, G. S.; Sidel'nikov, G. B.

2014-09-01

Different methods of optimal and adaptive processing of hydroacoustic signals for multipath propagation and scattering are considered. Advantages and drawbacks of the classical adaptive (Capon, MUSIC, and Johnson) algorithms and "fast" projection algorithms are analyzed for the case of multipath propagation and scattering of strong signals. The classical optimal approaches to detecting multipath signals are presented. A mechanism of controlled normalization of strong signals is proposed to automatically detect weak signals. The results of simulating the operation of different detection algorithms for a linear equidistant array under multipath propagation and scattering are presented. An automatic detector is analyzed, which is based on classical or fast projection algorithms, which estimates the background proceeding from median filtering or the method of bilateral spatial contrast.

Hydroacoustic estimates of fish biomass and spatial distributions in shallow lakes

NASA Astrophysics Data System (ADS)

Lian, Yuxi; Huang, Geng; Godlewska, Małgorzata; Cai, Xingwei; Li, Chang; Ye, Shaowen; Liu, Jiashou; Li, Zhongjie

2017-03-01

We conducted acoustical surveys with a horizontal beam transducer to detect fish and with a vertical beam transducer to detect depth and macrophytes in two typical shallow lakes along the middle and lower reaches of the Changjiang (Yangtze) River in November 2013. Both lakes are subject to active fish management with annual stocking and removal of large fish. The purpose of the study was to compare hydroacoustic horizontal beam estimates with fish landings. The preliminary results show that the fish distribution patterns differed in the two lakes and were affected by water depth and macrophyte coverage. The hydroacoustically estimated fish biomass matched the commercial catch very well in Niushan Lake, but it was two times higher in Kuilei Lake. However, acoustic estimates included all fish, whereas the catch included only fish >45 cm (smaller ones were released). We were unable to determine the proper regression between acoustic target strength and fish length for the dominant fish species in the two lakes.

Hydroacoustic estimates of fish biomass and spatial distributions in shallow lakes

NASA Astrophysics Data System (ADS)

Lian, Yuxi; Huang, Geng; Godlewska, Małgorzata; Cai, Xingwei; Li, Chang; Ye, Shaowen; Liu, Jiashou; Li, Zhongjie

2018-03-01

We conducted acoustical surveys with a horizontal beam transducer to detect fish and with a vertical beam transducer to detect depth and macrophytes in two typical shallow lakes along the middle and lower reaches of the Changjiang (Yangtze) River in November 2013. Both lakes are subject to active fish management with annual stocking and removal of large fish. The purpose of the study was to compare hydroacoustic horizontal beam estimates with fish landings. The preliminary results show that the fish distribution patterns differed in the two lakes and were affected by water depth and macrophyte coverage. The hydroacoustically estimated fish biomass matched the commercial catch very well in Niushan Lake, but it was two times higher in Kuilei Lake. However, acoustic estimates included all fish, whereas the catch included only fish >45 cm (smaller ones were released). We were unable to determine the proper regression between acoustic target strength and fish length for the dominant fish species in the two lakes.

Blockages to Creativity.

ERIC Educational Resources Information Center

Olivier, A.

The paper examines the nature of creativity and blockages to its expression especially in home and school settings in South Africa. A definition of creativity is offered which stresses the production of an original outcome or achievement. The creative process is broken down into the steps of preparation, incubation, illumination, and verification.…

Development and validation of hydroacoustic monitoring concepts for the coastal German Bight (SE North Sea)

NASA Astrophysics Data System (ADS)

Mielck, Finn; Hass, H. Christian; Holler, Peter; Bartholomä, Alexander; Neumann, Andreas; Kröncke, Ingrid; Reimers, Hans-Christian; Capperucci, Ruggero

2016-04-01

The joint research project WIMO (Wissenschaftliche Monitoringkonzepte für die Deutsche Bucht/Scientific Monitoring Concepts for the German Bight, NE North Sea) aims at providing methods for detection and analysis of seabed habitats using modern remote sensing techniques. Our subproject focuses on hydroacoustic techniques in order to gain information about seafloor environments and sediment dynamics. In a timeframe of four years, several key areas in the German Bight were repeatedly observed using different hydroacoustic gear (i. e. sidescan sonars, single/multibeam echo sounders and sub-bottom profilers). In order to ground-truth the acoustic data, hundreds of grab samples and underwater videos were taken. With these techniques it is possible to distinguish between different seafloor habitats, which range from muddy to sandy seafloors (esp. near the barrier islands) to rugged or vegetated/populated reefs around Helgoland. The conducted monitoring program revealed seasonal changes regarding the abundance of the sand mason worm (Lanice conchilega) and the brittle star (Amphiora filiformis) as well as ongoing sedimentary processes driven by tidal currents and wind/storms. It was also possible to determine relationships between sediment characteristics and benthos in some key areas. An essential part of our project included a comparison between the datasets obtained with different hydroacoustic devices, configurations, and evaluation methods in the same study areas. The investigation reveals that there could be distinct differences in interpreting the data and hence in the determination of prevailing seafloor habitats, especially in very heterogeneous areas and at transition zones between the habitats. Therefore, it is recommended to employ more than one hydroacoustic system (preferably a singlebeam device combined with a wide-swath sonar system) synchronously during a survey in order to gain more reliable and detailed information about the seafloor environments. The

Effect of Blockage and Location on Mixing of Swirling Coaxial Jets in a Non-expanding Circular Confinement

NASA Astrophysics Data System (ADS)

Patel, V. K.; Singh, S. N.; Seshadri, V.

2013-06-01

A study is conducted to evolve an effective design concept to improve mixing in a combustor chamber to reduce the amount of intake air. The geometry used is that of a gas turbine combustor model. For simplicity, both the jets have been considered as air jets and effect of heat release and chemical reaction has not been modeled. Various contraction shapes and blockage have been investigated by placing them downstream at different locations with respect to inlet to obtain better mixing. A commercial CFD code `Fluent 6.3' which is based on finite volume method has been used to solve the flow in the combustor model. Validation is done with the experimental data available in literature using standard k-ω turbulence model. The study has shown that contraction and blockage at optimum location enhances the mixing process. Further, the effect of swirl in the jets has also investigated.

DEMON-type algorithms for determination of hydro-acoustic signatures of surface ships and of divers

NASA Astrophysics Data System (ADS)

Slamnoiu, G.; Radu, O.; Rosca, V.; Pascu, C.; Damian, R.; Surdu, G.; Curca, E.; Radulescu, A.

2016-08-01

With the project “System for detection, localization, tracking and identification of risk factors for strategic importance in littoral areas”, developed in the National Programme II, the members of the research consortium intend to develop a functional model for a hydroacoustic passive subsystem for determination of acoustic signatures of targets such as fast boats and autonomous divers. This paper presents some of the results obtained in the area of hydroacoustic signal processing by using DEMON-type algorithms (Detection of Envelope Modulation On Noise). For evaluation of the performance of various algorithm variations we have used both audio recordings of the underwater noise generated by ships and divers in real situations and also simulated noises. We have analysed the results of processing these signals using four DEMON algorithm structures as presented in the reference literature and a fifth DEMON algorithm structure proposed by the authors of this paper. The algorithm proposed by the authors generates similar results to those obtained by applying the traditional algorithms but requires less computing resources than those and at the same time it has proven to be more resilient to random noise influence.

On blockage effects for a marine hydrokinetic turbine in free surface proximity

NASA Astrophysics Data System (ADS)

Banerjee, A.; Kolekar, N.

2016-12-01

Experimental investigation was carried out with a three-bladed, constant chord marine hydrokinetic turbine to understand the influence of free surface proximity on blockage effects and near wake flow field. The turbine was placed at various depths of immersion as rotational speeds and flow speeds were varied; thrust and torque data was acquired through a submerged thrust torque sensor positioned in-line with the turbine axis. Blockage effects were quantified in terms of changes in power coefficient and were found to be dependent on flow velocity, rotational speed and blade-tip clearence (from free-surface). Flow acceleration near turbine rotation plane was attributed to blockage offered by the rotor, wake, and free surface deformation; the resulting performance improvements were calculated based on the measured thrust values. In addition, stereoscopic particle imaging velocimetry was carried out in the near-wake region using time-averaged and phase-averaged techniques to understand the mechanism responsible for variation of torque (and power coefficient) with rotational speed and free-surface proximity. Flow vizualisation revealed slower wake propagation for higher rotational velocities and increased assymetry in the wake with increasing free surface proximity. Improved performance at high rotational speed was attributed to enhanced wake blockage; performance enhancements with free-surface proximity was attributed to additional blockage effects caused by free surface deformation.

Workgroup for Hydraulic laboratory Testing and Verification of Hydroacoustic Instrumentation

USGS Publications Warehouse

Fulford, Janice M.; Armstrong, Brandy N.; Thibodeaux, Kirk G.

2015-01-01

An international workgroup was recently formed for hydraulic laboratory testing and verification of hydroacoustic instrumentation used for water velocity measurements. The activities of the workgroup have included one face to face meeting, conference calls and an inter-laboratory exchange of two acoustic meters among participating laboratories. Good agreement was found among four laboratories at higher tow speeds and poorer agreement at the lowest tow speed.

Statistical analysis and definition of blockages-prediction formulae for the wastewater network of Oslo by evolutionary computing.

PubMed

Ugarelli, Rita; Kristensen, Stig Morten; Røstum, Jon; Saegrov, Sveinung; Di Federico, Vittorio

2009-01-01

Oslo Vann og Avløpsetaten (Oslo VAV)-the water/wastewater utility in the Norwegian capital city of Oslo-is assessing future strategies for selection of most reliable materials for wastewater networks, taking into account not only material technical performance but also material performance, regarding operational condition of the system.The research project undertaken by SINTEF Group, the largest research organisation in Scandinavia, NTNU (Norges Teknisk-Naturvitenskapelige Universitet) and Oslo VAV adopts several approaches to understand reasons for failures that may impact flow capacity, by analysing historical data for blockages in Oslo.The aim of the study was to understand whether there is a relationship between the performance of the pipeline and a number of specific attributes such as age, material, diameter, to name a few. This paper presents the characteristics of the data set available and discusses the results obtained by performing two different approaches: a traditional statistical analysis by segregating the pipes into classes, each of which with the same explanatory variables, and a Evolutionary Polynomial Regression model (EPR), developed by Technical University of Bari and University of Exeter, to identify possible influence of pipe's attributes on the total amount of predicted blockages in a period of time.Starting from a detailed analysis of the available data for the blockage events, the most important variables are identified and a classification scheme is adopted.From the statistical analysis, it can be stated that age, size and function do seem to have a marked influence on the proneness of a pipeline to blockages, but, for the reduced sample available, it is difficult to say which variable it is more influencing. If we look at total number of blockages the oldest class seems to be the most prone to blockages, but looking at blockage rates (number of blockages per km per year), then it is the youngest class showing the highest blockage rate

Development of an Infection-Responsive Fluorescent Sensor for the Early Detection of Urinary Catheter Blockage.

PubMed

Milo, Scarlet; Acosta, Florianne B; Hathaway, Hollie J; Wallace, Laura A; Thet, Naing T; Jenkins, A Toby A

2018-03-23

Formation of crystalline biofilms following infection by Proteus mirabilis can lead to encrustation and blockage of long-term indwelling catheters, with serious clinical consequences. We describe a simple sensor, placed within the catheter drainage bag, to alert of impending blockage via a urinary color change. The pH-responsive sensor is a dual-layered polymeric "lozenge", able to release the self-quenching dye 5(6)-carboxyfluorescein in response to the alkaline urine generated by the expression of bacterial urease. Sensor performance was evaluated within a laboratory model of the catheterized urinary tract, infected with both urease positive and negative bacterial strains under conditions of established infection, achieving an average "early warning" of catheter blockage of 14.5 h. Signaling only occurred following infection with urease positive bacteria. Translation of these sensors into a clinical environment would allow appropriate intervention before the occurrence of catheter blockage, a problem for which there is currently no effective control method.

Inferred fish behavior its implications for hydroacoustic surveys in nearshore habitats

USGS Publications Warehouse

DuFour, Mark R.; Mayer, Christine M.; Qian, Song S.; Vandergoot, Christopher; Kraus, Richard T.; Kocovsky, Patrick; Warner, David M.

2018-01-01

Population availability and vessel avoidance effects on hydroacoustic abundance estimates may be scale dependent; therefore, it is important to evaluate these biases across systems. We performed an inter-ship comparison survey to determine the effect of vessel size, day-night period, depth, and environmental gradients on walleye (Sander vitreus) density estimates in Lake Erie, an intermediate-scaled system. Consistent near-bottom depth distributions coupled with horizontal fish movements relative to vessel paths indicated avoidance behavior contributed to higher walleye densities from smaller vessels in shallow water (i.e., <15 m), although the difference decreased with increasing depth. Diel bank migrations in response to seasonally varying onshore-to-offshore environmental gradients likely contributed to day-night differences in densities between sampling locations and seasons. Spatial and unexplained variation accounted for a high proportion of total variation; however, increasing sampling intensity can mitigate effects on precision. Therefore, researchers should minimize systematic avoidance and availability related biases (i.e., vessel and day-night period) to improve population abundance estimates. Quantifying availability and avoidance behavior effects and partitioning sources of variation provides informed flexibility for designing future hydroacoustic surveys in shallow-water nearshore environments.

Hydroacoustic Signals Recorded by the International Monitoring System

NASA Astrophysics Data System (ADS)

Blackman, D.; de Groot-Hedlin, C.; Orcutt, J.; Harben, P.

2002-12-01

Networks of hydrophones, such as the hydroacoustic part of the International Monitoring System (IMS), and hydrophone arrays, such as the U.S. Navy operates, record many types of signals, some of which travel thousands of kilometers in the oceanic sound channel. Abyssal earthquakes generate many such individual events and occasionally occur in swarms. Here we focus on signals generated by other types of sources, illustrating their character with recent data, mostly from the Indian Ocean. Shipping generates signals in the 5-40 Hz band. Large airgun arrays can generate T-waves that travel across an ocean basin if the near-source seafloor has appropriate depth/slope. Airgun array shots from our 2001 experiment were located with an accuracy of 25-40 km at 700-1000 km ranges, using data from a Diego Garcia tripartite sensor station. Shots at greater range (up to 4800 km) were recorded at multiple stations but their higher background noise levels in the 5-30 Hz band resulted in location errors of ~100 km. Imploding glass spheres shattered within the sound channel produce a very impulsive arrival, even after propagating 4400 km. Recordings of the sphere signal have energy concentrated in the band above 40 Hz. Natural sources such as undersea volcanic eruptions and marine mammals also produce signals that are clearly evident in hydrophone recordings. For whales, the frequency range is 20~120Hz and specific patterns of vocalization characterize different species. Volcanic eruptions typically produce intense swarms of acoustic activity that last days-weeks and the source area can migrate tens of kms during the period. The utility of these types of hydroacoustic sources for research and/or monitoring purposes depends on the accuracy with which recordings can be used to locate and quantitatively characterize the source. Oceanic weather, both local and regional, affect background noise levels in key frequency bands at the recording stations. Databases used in forward modeling of

Hydroacoustic estimates of abundance and spatial distribution of pelagic prey fishes in western Lake Superior

USGS Publications Warehouse

Mason, Doran M.; Johnson, Timothy B.; Harvey, Chris J.; Kitchell, James F.; Schram, Stephen T.; Bronte, Charles R.; Hoff, Michael H.; Lozano, Stephen J.; Trebitz, Anett S.; Schreiner, Donald R.; Lamon, E. Conrad; Hrabik, Thomas R.

2005-01-01

Lake herring (Coregonus artedi) and rainbow smelt (Osmerus mordax) are a valuable prey resource for the recovering lake trout (Salvelinus namaycush) in Lake Superior. However, prey biomass may be insufficient to support the current predator demand. In August 1997, we assessed the abundance and spatial distribution of pelagic coregonines and rainbow smelt in western Lake Superior by combining a 120 kHz split beam acoustics system with midwater trawls. Coregonines comprised the majority of the midwater trawl catches and the length distributions for trawl caught fish coincided with estimated sizes of acoustic targets. Overall mean pelagic prey fish biomass was 15.56 kg ha−1 with the greatest fish biomass occurring in the Apostle Islands region (27.98 kg ha−1), followed by the Duluth Minnesota region (20.22 kg ha−1), and with the lowest biomass occurring in the open waters of western Lake Superior (9.46 kg ha−1). Biomass estimates from hydroacoustics were typically 2–134 times greater than estimates derived from spring bottom trawl surveys. Prey fish biomass for Lake Superior is about order of magnitude less than acoustic estimates for Lakes Michigan and Ontario. Discrepancies observed between bioenergetics-based estimates of predator consumption of coregonines and earlier coregonine biomass estimates may be accounted for by our hydroacoustic estimates.

Blockage effects on the hydrodynamic performance of a marine cross-flow turbine.

PubMed

Consul, Claudio A; Willden, Richard H J; McIntosh, Simon C

2013-02-28

This paper explores the influence of blockage and free-surface deformation on the hydrodynamic performance of a generic marine cross-flow turbine. Flows through a three-bladed turbine with solidity 0.125 are simulated at field-test blade Reynolds numbers, O(10(5)-10(6)), for three different cross-stream blockages: 12.5, 25 and 50 per cent. Two representations of the free-surface boundary are considered: rigid lid and deformable free surface. Increasing the blockage is observed to lead to substantial increases in the power coefficient; the highest power coefficient computed is 1.23. Only small differences are observed between the two free-surface representations, with the deforming free-surface turbine out-performing the rigid lid turbine by 6.7 per cent in power at the highest blockage considered. This difference is attributed to the increase in effective blockage owing to the deformation of the free surface. Hydrodynamic efficiency, the ratio of useful power generated to overall power removed from the flow, is found to increase with blockage, which is consistent with the presence of a higher flow velocity through the core of the turbine at higher blockage ratios. Froude number is found to have little effect on thrust and power coefficients, but significant influence on surface elevation drop across the turbine.

Lattice Boltzmann approach for hydro-acoustic waves generated by tsunamigenic sea bottom displacement

NASA Astrophysics Data System (ADS)

Prestininzi, P.; Abdolali, A.; Montessori, A.; Kirby, J. T.; La Rocca, Michele

2016-11-01

Tsunami waves are generated by sea bottom failures, landslides and faults. The concurrent generation of hydro-acoustic waves (HAW), which travel much faster than the tsunami, has received much attention, motivated by their possible exploitation as precursors of tsunamis. This feature makes the detection of HAW particularly well-suited for building an early-warning system. Accuracy and efficiency of the modeling approaches for HAW thus play a pivotal role in the design of such systems. Here, we present a Lattice Boltzmann Method (LBM) for the generation and propagation of HAW resulting from tsunamigenic ground motions and verify it against commonly employed modeling solutions. LBM is well known for providing fast and accurate solutions to both hydrodynamics and acoustics problems, thus it naturally becomes a candidate as a comprehensive computational tool for modeling generation and propagation of HAW.

Relations of Early Goal-Blockage Response and Gender to Subsequent Tantrum Behavior

ERIC Educational Resources Information Center

Sullivan, Margaret W.; Lewis, Michael

2012-01-01

Infants and their mothers participated in a longitudinal study of the sequelae of infant goal-blockage responses. Four-month-old infants participated in a standard contingency learning and goal-blockage procedure during which anger and sad facial expressions to the blockage were coded. When infants were 12 and 20 months old, mothers completed a…

Location, Characterization and Quantification of Hydroacoustic Signals in the Indian Ocean

DTIC Science & Technology

2004-10-01

and P-F Piserchia, Long range detection of hydroacoustic signals from large Icebergs in the Ross Sea, Antarctica, Ear. and Plan. Sci. Let., 203:519...Bohnenstiehl, and E. Chapp, Long Range Acoustic Propagation of High Frequency Energy in the Indian Ocean from Icebergs and Earthquakes, 26* Seismic...calculated for each hydrophone site in the Indian Ocean, which assists in understanding detection thresholds for each station at a range of frequencies

Developments in hot-film anemometry measurements of hydroacoustic particle motion

NASA Astrophysics Data System (ADS)

Dubbelday, Pieter S.; Apostolico, Virgil V.; Diebel, Dean L.

1988-08-01

Hot film anemometry may be used to measure particle motion in hydroacoustic fields. Since the cylindrical sensors used thus far are very fragile, the method is little suited for use outside the laboratory. The measurement of the response of a more rugged conical sensor is reported here. Another way of protecting the sensor consists of packaging the sensor in a rubber liquid filled boot. This also prevents fouling and bubble formation on the heated film. The response shows a resonance at low frequency, ascribed to the liquid filled boot, which may be used for enhanced response in a limited frequency region. The response of a hot film anemometer to vertical hydroacoustic particle motion is influenced by free convection, which acts as a bias flow. The output was shown to be proportional to particle displacement for a wide range of parameters. It was expected that an imposed bias flow would increase the output and remove the dependence on the direction of gravity. Therefore, a hot-film sensor (diameter d) was subjected to an underwater jet from a nozzle. The output showed a transition from being proportional to particle speed, to being proportional to particle displacement, depending on the angular frequency omega and imposed flow speed omega. The transition takes place when a dimensionless number omega, defined as omega = omega/nu is of order 1.

Efficacy of Yavakshara Taila Uttarabasti in the management of fallopian tube blockage.

PubMed

Baria, Hetal P; Donga, Shilpa B; Dei, Laxmipriya

2015-01-01

Tubal blockage is one of the most common causative factors for female barrenness. It accounts for about 25-35% of female infertility. It is very difficult to manage, as the treatment choices for it are only tubal re-constructive surgery and in vitro fertilization (IVF). On the other hand, there is not established any reliable Ayurvedic treatment for the tubal blockage. It is the need of the time to establish an efficient and cost-effective therapy for this problem. To evaluate the efficacy of Yavakshara Taila Uttarabasti in fallopian tubal blockage. Patients of childbearing age with active marital life of 1 year or more, having complaint of failure to conceive with at least one fallopian tube blockage were selected. Total 19 patients were registered with 42.11% unilateral and 57.89% bilateral tubal blockage. Yavakshara Taila (5 ml) Intrauterine Uttarabasti was given for 6 days (with interval of 3 days in between), after completion of menstrual cycle for two consecutive cycles. The tubal patency was found in 68.75% of patients and conception was achieved in 6.25% of patients. Yavakshara Taila Uttarabasti an effective procedure for treating tubal blockage with no apparent evidence of complication.

Assessment of Hydroacoustic Propagation Using Autonomous Hydrophones in the Scotia Sea

DTIC Science & Technology

2010-09-01

Award No. DE-AI52-08NA28654 Proposal No. BAA08-36 ABSTRACT The remote area of the Atlantic Ocean near the Antarctic Peninsula and the South...hydroacoustic blind spot. To investigate the sound propagation and interferences affected by these landmasses in the vicinity of the Antarctic polar...from large icebergs (near-surface sources) were utilized as natural sound sources. Surface sound sources, e.g., ice-related events, tend to suffer less

Effect of blockage ratio on drag and pressure distributions for bodies of revolution at transonic speeds

NASA Technical Reports Server (NTRS)

Couch, L. M.; Brooks, C. W., Jr.

1973-01-01

Experimental data were obtained in two wind tunnels for 13 models over a Mach number range from 0.70 to 1.02. Effects of increasing test-section blockage ratio in the transonic region near a Mach number of 1.0 included change in the shape of the drag curves, premature drag creep, delayed drag divergence, and a positive increment of pressures on the model afterbodies. Effects of wall interference were apparent in the data even for a change in blockage ratio from a very low 0.000343 to an even lower 0.000170. Therefore, models having values of blockage ratio of 0.0003 - an order of magnitude below the previously considered safe value of 0.0050 - had significant errors in the drag-coefficient values obtained at speeds near a Mach number of 1.0. Furthermore, the flow relief afforded by slots or perforations in test-section walls - designed according to previously accepted criteria for interference-free subsonic flow - does not appear to be sufficient to avoid significant interference of the walls with the model flow field for Mach numbers very close to 1.0.

Efficacy of Yavakshara Taila Uttarabasti in the management of fallopian tube blockage

PubMed Central

Baria, Hetal P.; Donga, Shilpa B.; Dei, Laxmipriya

2015-01-01

Introduction: Tubal blockage is one of the most common causative factors for female barrenness. It accounts for about 25-35% of female infertility. It is very difficult to manage, as the treatment choices for it are only tubal re-constructive surgery and in vitro fertilization (IVF). On the other hand, there is not established any reliable Ayurvedic treatment for the tubal blockage. It is the need of the time to establish an efficient and cost-effective therapy for this problem. Aim: To evaluate the efficacy of Yavakshara Taila Uttarabasti in fallopian tubal blockage. Materials and Methods: Patients of childbearing age with active marital life of 1 year or more, having complaint of failure to conceive with at least one fallopian tube blockage were selected. Total 19 patients were registered with 42.11% unilateral and 57.89% bilateral tubal blockage. Yavakshara Taila (5 ml) Intrauterine Uttarabasti was given for 6 days (with interval of 3 days in between), after completion of menstrual cycle for two consecutive cycles. Results: The tubal patency was found in 68.75% of patients and conception was achieved in 6.25% of patients. Conclusion: Yavakshara Taila Uttarabasti an effective procedure for treating tubal blockage with no apparent evidence of complication. PMID:26730135

A new paradigm for the reversible blockage of whisker sensory transmission.

PubMed

Gener, Thomas; Reig, Ramon; Sanchez-Vives, Maria V

2009-01-30

The objective of this study was to explore a paradigm that would allow a temporary deprivation of whisker information lasting for a few hours. An additional requirement was to be non-invasive in order to be usable in awake chronically implanted rats without inducing stress. With that aim, electrophysiological recordings from the barrel cortex of anesthetized rats were obtained. The pressure of an air-puff (5-10 ms) delivered to the whiskers was adjusted to evoke a consistent response of around 100 microV (extracellular) or approximately 5 mV (intracellular) in the contralateral cortex. Lidocaine was then locally applied in different forms (cream, local injection, aerosol, drops) and concentrations (2-10%) to the base of the whiskers. The stimulus-induced response was monitored once every 5s for several hours (3-6h) in order to characterize its course of action. Local injection of lidocaine induced the fastest and most complete blockage, but was ruled out for being invasive. Out of the remaining forms of application, a lidocaine drop (0.4 ml, 10%) to the base of the whiskers was found to induce a reliable blockage (to an average 9% the original response). The maximum effect was reached after 150-200 min, and the response was totally recovered approximately 300 min after lidocaine application. This characterization should be useful to induce an efficient, short term and reversible blockage of whisker sensory transmission in both anesthetized and awake preparations, while not causing stress in an awake animal.

FFM water mockup studies of the near-wake region of permeable flow blockages. [LMFBR

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

Sheppard, J. D.

1976-10-01

An experimental study of transport in the near-wake region of permeable, planar flow blockages was conducted in a vertical-flow channel with a hexagonal cross section. Experiments included measurements of axial pressure distributions along channel walls exposed to the free stream and wake region and pressure differences between the free stream and wake regions at fixed axial positions. Further, time constants for scalar decay in the near-wake region were determined by salt conductivity tests. A single blockage geometry was used in all tests; the blockage, which was attached to the channel wall, obstructed 58 percent of the cross section when themore » blockage was solid. For one series of tests, discrete jets were machined into the blockage and water was metered into the recirculation zone at velocities of the order of the mean channel velocity. Increased jet velocity reduced the resistence time of salt in the recirculation zone, and when the jet velocity was as high as the accelerated free stream flow at the vena contracta, counterrotating cells were introduced in the recirculating zone. In a second series of tests, uniformly spaced holes were drilled in the blockages to give blockage porosities of 11 and 24 percent. The residence time of salt in the near wake decreased significantly as the blockage porosity was increased to 24 percent.« less

PWR FLECHT SEASET 163-Rod Bundle Flow Blockage Task data report. NRC/EPRI/Westinghouse report No. 13, August-October 1982

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

Loftus, M J; Hochreiter, L E; McGuire, M F

This report presents data from the 163-Rod Bundle Blow Blockage Task of the Full-Length Emergency Cooling Heat Transfer Systems Effects and Separate Effects Test Program (FLECHT SEASET). The task consisted of forced and gravity reflooding tests utilizing electrical heater rods with a cosine axial power profile to simulate PWR nuclear core fuel rod arrays. These tests were designed to determine effects of flow blockage and flow bypass on reflooding behavior and to aid in the assessment of computational models in predicting the reflooding behavior of flow blockage in rod bundle arrays.

Turbulence Intensity at Inlet of 80- by 120-Foot Wind Tunnel Caused by Upwind Blockage

NASA Technical Reports Server (NTRS)

Salazar, Denise; Yuricich, Jillian

2014-01-01

In order to estimate the magnitude of turbulence in the National Full-Scale Aerodynamics Complex (NFAC) 80- by 120-Foot Wind Tunnel (80 x 120) caused by buildings located upwind from the 80 x 120 inlet, a 150th-scale study was performed that utilized a nominal two-dimensional blockage placed ahead of the inlet. The distance of the blockage ahead of the inlet was varied. This report describes velocity measurements made in the plane of the 80 x 120 model inlet for the case of zero ambient (atmospheric) wind.

Exploring relationships of catheter-associated urinary tract infection and blockage in people with long-term indwelling urinary catheters.

PubMed

Wilde, Mary H; McMahon, James M; Crean, Hugh F; Brasch, Judith

2017-09-01

To describe and explore relationships among catheter problems in long-term indwelling urinary catheter users, including excess healthcare use for treating catheter problems. Long-term urinary catheter users experience repeated problems with catheter-related urinary tract infection and blockage of the device, yet little has been reported of the patterns and relationships among relevant catheter variables. Secondary data analysis was conducted from a sample in a randomised clinical trial, using data from the entire sample of 202 persons over 12 months' participation. Descriptive statistics were used to characterise the sample over time. Zero-inflated negative binomial models were employed for logistic regressions to evaluate predictor variables of the presence/absence and frequencies of catheter-related urinary tract infection and blockage. Catheter-related urinary tract infection was marginally associated with catheter blockage. Problems reported at least once per person in the 12 months were as follows: catheter-related urinary tract infection 57%, blockage 34%, accidental dislodgment 28%, sediment 87%, leakage (bypassing) 67%, bladder spasms 59%, kinks/twists 42% and catheter pain 49%. Regression analysis demonstrated that bladder spasms were significantly related to catheter-related urinary tract infection and sediment amount, and catheter leakages were marginally significantly and positively related to catheter-related urinary tract infection. Frequencies of higher levels of sediment and catheter leakage were significantly associated with higher levels of blockage, and being female was associated with fewer blockages. Persons who need help with eating (more disabled) were also more likely to have blockages. Catheter-related urinary tract infection and blockage appear to be related and both are associated with additional healthcare expenditures. More research is needed to better understand how to prevent adverse catheter outcomes and patterns of problems in

Improved Visualization of Hydroacoustic Plumes Using the Split-Beam Aperture Coherence.

PubMed

Blomberg, Ann E A; Weber, Thomas C; Austeng, Andreas

2018-06-25

Natural seepage of methane into the oceans is considerable, and plays a role in the global carbon cycle. Estimating the amount of this greenhouse gas entering the water column is important in order to understand their environmental impact. In addition, leakage from man-made structures such as gas pipelines may have environmental and economical consequences and should be promptly detected. Split beam echo sounders (SBES) detect hydroacoustic plumes due to the significant contrast in acoustic impedance between water and free gas. SBES are also powerful tools for plume characterization, with the ability to provide absolute acoustic measurements, estimate bubble trajectories, and capture the frequency dependent response of bubbles. However, under challenging conditions such as deep water and considerable background noise, it can be difficult to detect the presence of gas seepage from the acoustic imagery alone. The spatial coherence of the wavefield measured across the split beam sectors, quantified by the coherence factor (CF), is a computationally simple, easily available quantity which complements the acoustic imagery and may ease the ability to automatically or visually detect bubbles in the water column. We demonstrate the benefits of CF processing using SBES data from the Hudson Canyon, acquired using the Simrad EK80 SBES. We observe that hydroacoustic plumes appear more clearly defined and are easier to detect in the CF imagery than in the acoustic backscatter images.

Hydroacoustic Assessment of Behavioral Responses by Fish Passing Near an Operating Tidal Turbine in the East River, New York

DOE PAGES

Bevelhimer, Mark; Scherelis, Constantin C.; Colby, Jonathan; ...

2017-06-13

An important environmental issue facing the marine and hydrokinetic energy industry is whether fish that encounter underwater energy devices are likely to be struck and injured by moving components, primarily rotating turbine blades. The automated analysis of nearly 3 weeks of multibeam hydroacoustics data identified about 35,000 tracks of fish passing a tidal turbine in the East River, New York. These tracks included both individual fish and schools during periods with the turbine absent, the turbine present and operating, and the turbine present but not operating. The density of fish in the sampled area when the turbine was absent wasmore » roughly twice the density observed when the turbine was in place, particularly when the turbine was operating. This suggests that some avoidance occurred before fish were close enough to the turbine to be observed by the hydroacoustics system. Various measures of swimming behavior (direction, velocity, and linearity) were calculated for each track and evaluated for indication of behavioral responses to turbine presence and operation. Fish tracks were grouped based on tidal cycle, current velocity, and swimming direction and were evaluated with respect to turbine presence and operation and with respect to distance from the turbine. Nonparametric tests (Kolmogorov–Smirnov test) and multivariate analysis (canonical discriminant analysis) found significant differences among groups with respect to turbine presence and operation, suggesting that some fish responded to the turbine by adjusting swimming behavior, such as making small adjustments to swimming direction and velocity as they passed near the turbine. We found no evidence that fish were being struck by rotating blades, but there did appear to be large-scale avoidance initiated out of the range of the hydroacoustics detection system. Furthermore, more study is needed to determine whether such avoidance behavior has significant ramifications for normal fish movement

Hydroacoustic Assessment of Behavioral Responses by Fish Passing Near an Operating Tidal Turbine in the East River, New York

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

Bevelhimer, Mark; Scherelis, Constantin C.; Colby, Jonathan

An important environmental issue facing the marine and hydrokinetic energy industry is whether fish that encounter underwater energy devices are likely to be struck and injured by moving components, primarily rotating turbine blades. The automated analysis of nearly 3 weeks of multibeam hydroacoustics data identified about 35,000 tracks of fish passing a tidal turbine in the East River, New York. These tracks included both individual fish and schools during periods with the turbine absent, the turbine present and operating, and the turbine present but not operating. The density of fish in the sampled area when the turbine was absent wasmore » roughly twice the density observed when the turbine was in place, particularly when the turbine was operating. This suggests that some avoidance occurred before fish were close enough to the turbine to be observed by the hydroacoustics system. Various measures of swimming behavior (direction, velocity, and linearity) were calculated for each track and evaluated for indication of behavioral responses to turbine presence and operation. Fish tracks were grouped based on tidal cycle, current velocity, and swimming direction and were evaluated with respect to turbine presence and operation and with respect to distance from the turbine. Nonparametric tests (Kolmogorov–Smirnov test) and multivariate analysis (canonical discriminant analysis) found significant differences among groups with respect to turbine presence and operation, suggesting that some fish responded to the turbine by adjusting swimming behavior, such as making small adjustments to swimming direction and velocity as they passed near the turbine. We found no evidence that fish were being struck by rotating blades, but there did appear to be large-scale avoidance initiated out of the range of the hydroacoustics detection system. Furthermore, more study is needed to determine whether such avoidance behavior has significant ramifications for normal fish movement

Investigation of very low blockage ratio boattail models in the Langley 16-foot transonic tunnel

NASA Technical Reports Server (NTRS)

Reubush, D. E.

1976-01-01

An investigation at an angle of attack of 0 deg was conducted in a 16 foot transonic tunnel at Mach numbers from 0.4 to 1.05 to determine the limits in Mach number at which valid boattail pressure drag data may be obtained with very low blockage ratio bodies. Extreme care was exercised when examining any data taken at subsonic Mach numbers very near 1.0 and lower than the supersonic Mach number at which shock reflections miss the model. Boattail pressure coefficient distributions did not indicate any error, but when integrated boattail pressure drag data was plotted as a function of Mach number, data which were in error were identified.

Blockage Testing in the NASA Glenn 225 Square Centimeter Supersonic Wind Tunnel

NASA Technical Reports Server (NTRS)

Sevier, Abigail; Davis, David; Schoenenberger, Mark

2017-01-01

A feasibility study is in progress at NASA Glenn Research Center to implement a magnetic suspension and balance system in the 225 sq cm Supersonic Wind Tunnel for the purpose of testing the dynamic stability of blunt bodies. An important area of investigation in this study was determining the optimum size of the model and the iron spherical core inside of it. In order to minimize the required magnetic field and thus the size of the magnetic suspension system, it was determined that the test model should be as large as possible. Blockage tests were conducted to determine the largest possible model that would allow for tunnel start at Mach 2, 2.5, and 3. Three different forebody model geometries were tested at different Mach numbers, axial locations in the tunnel, and in both a square and axisymmetric test section. Experimental results showed that different model geometries produced more varied results at higher Mach Numbers. It was also shown that testing closer to the nozzle allowed larger models to start compared with testing near the end of the test section. Finally, allowable model blockage was larger in the axisymmetric test section compared with the square test section at the same Mach number. This testing answered key questions posed by the feasibility study and will be used in the future to dictate model size and performance required from the magnetic suspension system.

Development of a wall-shear-stress sensor and measurements in mini-channels with partial blockages

NASA Astrophysics Data System (ADS)

Afara, Samer; Medvescek, James; Mydlarski, Laurent; Baliga, Bantwal R.; MacDonald, Mark

2014-05-01

The design, construction, operation and validation of a wall-shear-stress sensor, and measurements obtained using this sensor in air flows downstream of partial blockages in a mini-channel are presented. The sensor consisted of a hot wire mounted over a small rectangular slot and operated using a constant-temperature anemometer. It was used to investigate flows similar to those within the mini-channels inside notebook computers. The overall goal of the present work was to develop a sensor suitable for measurements of the wall-shear stress in such flows, which can be used to validate corresponding numerical simulations, as the latter are known to be often surprisingly inaccurate. To this end, measurements of the wall-shear stress, and the corresponding statistical moments and power spectral densities, were obtained at different distances downstream of the partial blockage, with blockage ratios of 39.7, 59.2, and 76.3 %. The Reynolds number (based on average velocity and hydraulic diameter) ranged from 100 to 900. The results confirmed the presence of unsteadiness, separation, reattachment, and laminar-turbulent transition in the ostensibly laminar flow of air in mini-channels with partial blockages. The present results demonstrate why accurate numerical predictions of cooling air flows in laptop and notebook computers remain a challenging task.

Detection, Location, and Characterization of Hydroacoustic Signals Using Seafloor Cable Networks Offshore Japan

NASA Astrophysics Data System (ADS)

Suyehiro, K.; Sugioka, H.; Watanabe, T.

2008-12-01

The hydroacoustic monitoring by the International Monitoring System for CTBT (Comprehensive Nuclear- Test-Ban Treaty) verification system utilizes hydrophone stations (6) and seismic stations (5 and called T- phase stations) for worldwide detection. Some conspicuous signals of natural origin include those from earthquakes, volcanic eruptions, or whale calls. Among artificial sources are non-nuclear explosions and airgun shots. It is important for the IMS system to detect and locate hydroacoustic events with sufficient accuracy and correctly characterize the signals and identify the source. As there are a number of seafloor cable networks operated offshore Japanese islands basically facing the Pacific Ocean for monitoring regional seismicity, the data from these stations (pressure and seismic sensors) may be utilized to increase the capability of IMS. We use these data to compare some selected event parameters with those by IMS. In particular, there have been several unconventional acoustic signals in the western Pacific,which were also captured by IMS hydrophones across the Pacific in the time period of 2007-present. These anomalous examples and also dynamite shots used for seismic crustal structure studies and other natural sources will be presented in order to help improve the IMS verification capabilities for detection, location and characterization of anomalous signals.

Flood hazards along the Toutle and Cowlitz rivers, Washington, from a hypothetical failure of Castle Lake blockage

USGS Publications Warehouse

Laenen, Antonius; Orzol, L.L.

1987-01-01

A recent evaluation of groundwater and material in the blockage impounding Castle Lake shows that the blockage is potentially unstable against failure from piping due to heave and internal erosion when groundwater levels are seasonally high. There is also a remote possibility that a 6.8 or greater magnitude earthquake could occur in the Castle Lake area when groundwater levels are critically high. If this situation occurs, the debris blockage that confines Castle Lake could breach from successive slope failure with liquefaction of a portion of the blockage. A dam-break computer model was used to simulate discharge through a hypothetical breach in the Castle Lake blockage that could be caused by failure by heave, internal erosion, or liquefaction. Approximately 18,500 acre-ft of stored water would be released from an assumed breach that fully developed to a 1,000-ft width over a 15-minute time period. The resulting flood, incorporating 3.4 x 10 to the 6th power cu yd of the debris blockage, would reach a peak magnitude of 1,500,000 cu ft/s (cubic feet per second). The flood is also assumed to incorporate an additional 137x10 to the 6th power cu yd of saturated debris material from downstream deposits. Flow is considered to be hyperconcentrated with sediment throughout the course of the flood. The hypothetical hyperconcentrated flow is routed downstream, superimposed on normal winter flood flows by use of a one-dimensional unsteady-state numerical streamflow simulation model. From a starting magnitude of 1,500,000 cu ft/s, the peak increases to 2,100,000 cu ft/s at N-1 Dam (12 mi downstream) and attenuates to 1,200,000 cu ft/s at Kid Valley (25 mi downstream) , to 100,000 cu ft/s at Longview and the confluence of the Columbia River (65 mi downstream). From time of breach, the flood peak would take 2.2 hr to reach Toutle, 3.8 hr to reach Castle Rock, and 8.5 hr to reach Longview. Communities of Toutle , Castle Rock, Kelso, and Longview would experience extreme to

Infertility caused by tubal blockage: An ayurvedic appraisal

PubMed Central

Shukla (Upadhyaya), Kamayani; Karunagoda, Kaumadi; Dei, L. P.

2010-01-01

Tubal blockage is one of the most important factors for female infertility. This condition is not described in Ayurvedic classics, as the fallopian tube itself is not mentioned directly there. The present study is an effort to understand the disease according to Ayurvedic principles. Correlating fallopian tubes with the Artavavaha (Artava-bija-vaha) Srotas, its block is compared with the Sanga Srotodushti of this Srotas. Charak's opinion that the diseases are innumerable and newly discovered ones should be understood in terms of Prakriti, Adhishthana, Linga, and Aayatana, is followed, to describe this disease. An effort has been made to evaluate the role of all the three Doshas in producing blockage, with classification of the disease done as per the Dasha Roganika. PMID:22131704

Experimental evaluation of blockage ratio and plenum evacuation system flow effects on pressure distribution for bodies of revolution in 0.1 scale model test section of NASA Lewis Research Center's proposed altitude wind tunnel

NASA Technical Reports Server (NTRS)

Burley, Richard R.; Harrington, Douglas E.

1987-01-01

An experimental investigation was conducted in the slotted test section of the 0.1-scale model of the proposed Altitude Wind Tunnel to evaluate wall interference effects at tunnel Mach numbers from 0.70 to 0.95 on bodies of revolution with blockage rates of 0.43, 3, 6, and 12 percent. The amount of flow that had to be removed from the plenum chamber (which surrounded the slotted test section) by the plenum evacuation system (PES) to eliminate wall interference effects was determined. The effectiveness of tunnel reentry flaps in removing flow from the plenum chamber was examined. The 0.43-percent blockage model was the only one free of wall interference effects with no PES flow. Surface pressures on the forward part of the other models were greater than interference-free results and were not influenced by PES flow. Interference-free results were achieved on the aft part of the 3- and 6-percent blockage models with the proper amount of PES flow. The required PES flow was substantially reduced by opening the reentry flaps.

Structural Blockage: A Cross-national Study of Economic Dependency, State Efficacy, and Underdevelopment.

ERIC Educational Resources Information Center

Delacroix, Jacques; Ragin, Charles C.

1981-01-01

Presents a statistical analysis of dependency of developing nations on more highly developed and industrialized nations and relates this dependency to various degrees of economic development. The analysis is based on the structural blockage argument (one of several dependency arguments contained in many versions of dependency theory). Emphasizes…

Percolation blockage: A process that enables melt pond formation on first year Arctic sea ice

NASA Astrophysics Data System (ADS)

Polashenski, Chris; Golden, Kenneth M.; Perovich, Donald K.; Skyllingstad, Eric; Arnsten, Alexandra; Stwertka, Carolyn; Wright, Nicholas

2017-01-01

Melt pond formation atop Arctic sea ice is a primary control of shortwave energy balance in the Arctic Ocean. During late spring and summer, the ponds determine sea ice albedo and how much solar radiation is transmitted into the upper ocean through the sea ice. The initial formation of ponds requires that melt water be retained above sea level on the ice surface. Both theory and observations, however, show that first year sea ice is so highly porous prior to the formation of melt ponds that multiday retention of water above hydraulic equilibrium should not be possible. Here we present results of percolation experiments that identify and directly demonstrate a mechanism allowing melt pond formation. The infiltration of fresh water into the pore structure of sea ice is responsible for blocking percolation pathways with ice, sealing the ice against water percolation, and allowing water to pool above sea level. We demonstrate that this mechanism is dependent on fresh water availability, known to be predominantly from snowmelt, and ice temperature at melt onset. We argue that the blockage process has the potential to exert significant control over interannual variability in ice albedo. Finally, we suggest that incorporating the mechanism into models would enhance their physical realism. Full treatment would be complex. We provide a simple temperature threshold-based scheme that may be used to incorporate percolation blockage behavior into existing model frameworks.

Overview of hydro-acoustic current-measurement applications by the U.S. geological survey in Indiana

USGS Publications Warehouse

Morlock, Scott E.; Stewart, James A.

1999-01-01

The U.S. Geological Survey (USGS) maintains a network of 170 streamflow-gaging stations in Indiana to collect data from which continuous records of river discharges are produced. Traditionally, the discharge record from a station is produced by recording river stage and making periodic discharge measurements through a range of stage, then developing a relation between stage and discharge. Techniques that promise to increase data collection accuracy and efficiency include the use of hydro-acoustic instrumentation to measure river velocities. The velocity measurements are used to compute river discharge. In-situ applications of hydro-acoustic instruments by the USGS in Indiana include acoustic velocity meters (AVM's) at six streamflow-gaging stations and newly developed Doppler velocity meters (DVM's) at two stations. AVM's use reciprocal travel times of acoustic signals to measure average water velocities along acoustic paths, whereas DVM's use the Doppler shift of backscattered acoustic signals to compute water velocities. In addition to the in-situ applications, three acoustic Doppler current profilers (ADCP's) are used to make river-discharge measurements from moving boats at streamflow-gaging stations in Indiana. The USGS has designed and is testing an innovative unmanned platform from which to make ADCP discharge measurements.

Seismic and hydroacoustic analysis relevant to MH370

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

Stead, Richard J.

2014-07-03

The vicinity of the Indian Ocean is searched for open and readily available seismic and/or hydroacoustic stations that might have recorded a possible impact of MH370 with the ocean surface. Only three stations are identified: the IMS hydrophone arrays H01 and H08, and the Geoscope seismic station AIS. Analysis of the data from these stations shows an interesting arrival on H01 that has some interference from an Antarctic ice event, large amplitude repeating signals at H08 that obscure any possible arrivals, and large amplitude chaotic noise at AIS precludes any analysis at higher frequencies of interest. The results are thereforemore » rather inconclusive but may point to a more southerly impact location within the overall Indian Ocean search region. The results would be more useful if they can be combined with any other data that are not readily available.« less

Hfq Regulates Biofilm Gut Blockage That Facilitates Flea-Borne Transmission of Yersinia pestis

PubMed Central

Rempe, Katherine A.; Hinz, Angela K.

2012-01-01

The plague bacillus Yersinia pestis can achieve transmission by biofilm blockage of the foregut proventriculus of its flea vector. Hfq is revealed to be essential for biofilm blockage formation and acquisition and fitness of Y. pestis during flea gut infection, consistent with posttranscriptional regulatory mechanisms in plague transmission. PMID:22328669

A dolphin lower jaw is a hydroacoustic antenna of the traveling wave

NASA Astrophysics Data System (ADS)

Ryabov, Vyacheslav A.

2003-10-01

The purpose of the work is the analysis of a possible function of mental foramens as channels through which the echo passes in the lower jaw fat body and the determination of a role of channels and a skull in formation of the directivity of the dolphin echolocation hearing. Concrete problems were studying of the lower jaw morphology, modeling and calculation of a dolphin, tursiops truncatus p., echolocation hearing beam pattern. The outcomes of the work indicate those morphological structures of the lower jaw; the left and right half represents two hydroacoustic receiving antennas of the traveling wave type, TWA farther. The mental foramens of a dolphin lower jaw represent nonequidistant array of waveguide delay lines, and determine the phase and amplitude distribution of each of the antenna's array. The beam pattern of the echolocation hearing was calculated with the usage of the TWA model, and the allowance of flat sound wave diffraction. The beam pattern shape is naturally determined by the echolocation hearing functionality. It is equally well adapted both for echolocation and for pulses echo detection. A steepness of the bearing characteristic is estimated; it reaches 0.7 dB per degree.

Transcription blockage by stable H-DNA analogs in vitro

PubMed Central

Pandey, Shristi; Ogloblina, Anna M.; Belotserkovskii, Boris P.; Dolinnaya, Nina G.; Yakubovskaya, Marianna G.; Mirkin, Sergei M.; Hanawalt, Philip C.

2015-01-01

DNA sequences that can form unusual secondary structures are implicated in regulating gene expression and causing genomic instability. H-palindromes are an important class of such DNA sequences that can form an intramolecular triplex structure, H-DNA. Within an H-palindrome, the H-DNA and canonical B-DNA are in a dynamic equilibrium that shifts toward H-DNA with increased negative supercoiling. The interplay between H- and B-DNA and the fact that the process of transcription affects supercoiling makes it difficult to elucidate the effects of H-DNA upon transcription. We constructed a stable structural analog of H-DNA that cannot flip into B-DNA, and studied the effects of this structure on transcription by T7 RNA polymerase in vitro. We found multiple transcription blockage sites adjacent to and within sequences engaged in this triplex structure. Triplex-mediated transcription blockage varied significantly with changes in ambient conditions: it was exacerbated in the presence of Mn2+ or by increased concentrations of K+ and Li+. Analysis of the detailed pattern of the blockage suggests that RNA polymerase is sterically hindered by H-DNA and has difficulties in unwinding triplex DNA. The implications of these findings for the biological roles of triple-stranded DNA structures are discussed. PMID:26101261

A Web-GIS Procedure Based on Satellite Multi-Spectral and Airborne LIDAR Data to Map the Road blockage Due to seismic Damages of Built-Up Urban Areas

NASA Astrophysics Data System (ADS)

Costanzo, Antonio; Montuori, Antonio; Silva, Juan Pablo; Silvestri, Malvina; Musacchio, Massimo; Buongiorno, Maria Fabrizia; Stramondo, Salvatore

2016-08-01

In this work, a web-GIS procedure to map the risk of road blockage in urban environments through the combined use of space-borne and airborne remote sensing sensors is presented. The methodology concerns (1) the provision of a geo-database through the integration of space-borne multispectral images and airborne LiDAR data products; (2) the modeling of building vulnerability, based on the corresponding 3D geometry and construction time information; (3) the GIS-based mapping of road closure due to seismic- related building collapses based on the building characteristic height and the width of the road. Experimental results, gathered for the Cosenza urban area, allow demonstrating the benefits of both the proposed approach and the GIS-based integration of multi-platforms remote sensing sensors and techniques for seismic road assessment purposes.

Nonordinary excitation of hydroacoustic resonance in the hydroturbine circuit of the sayano-shushenskaya hydroelectric power plant

NASA Astrophysics Data System (ADS)

Karavosov, R. K.; Prozorov, A. G.

2011-05-01

Three cases of excitation of resonance oscillations in a circuit with an incompressible medium and a hydrodynamic source of narrow-band acoustic radiation are compared. It is asserted that the Francis turbine can transmit and reflect infrasonic disturbances. It is supposed that an array of immobile coaxial cylinders below the impeller will prevent hydroacoustic self-excitation in flow inside the water conduit.

Re-establishment of the IMS Hydroacoustic Station HA03, Robinson Crusoe Island, Chile

NASA Astrophysics Data System (ADS)

Haralabus, Georgios; Stanley, Jerry; Zampolli, Mario; Pautet, Lucie

2015-04-01

Water column hydrophone stations of the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO) International Monitoring System (IMS) comprise typically two triplets of moored hydrophones deployed on both sides of an island. Triplet distances vary approximately between 50 - 200 km from the island, with each triplet connected to the receiving shore equipment by fibre-optic submarine data cables. Once deployed, the systems relay underwater acoustic waveforms in the band 1 - 100 Hz in real time to Vienna via a shore based satellite link. The design life of hydroacoustic (HA) stations is at least 20 years, without need for any maintenance of the underwater system (UWS). The re-establishment of hydrophone station HA03 at Robinson Crusoe Island (670 km West of the Chilean mainland) is presented here. The station was destroyed in February 2010 by a Tsunami induced by an 8.8 magnitude earthquake. After a major engineering and logistical undertaking HA03 is now back in operation since April 2014. The main phases of the project are presented: (i) the installation of a shore facility for the reception of the hydrophone data from the UWS, which also relays the data back to the CTBTO International Data Center (IDC) in Vienna via a real-time satellite connection, (ii) the manufacturing and testing of the system to meet the stringent requirements of the Nuclear-Test-Ban Treaty, and (iii) the installation of the UWS with a state-of-the-art cable ship. Examples of data acquired by HA03 are also presented. These include hydroacoustic signals from the 1 April 2014 magnitude 8.2 earthquake in Northern Chile, bursting underwater bubbles from a submarine volcano near the Mariana Islands (15,000 Km away from the station), and vocalizations from the numerous marine mammals which transit in the vicinity of HA03. The use of CTBTO data for scientific purposes is possible via the virtual Data Exploitation Centre (vDEC), which is a platform that enables registered researchers to access

Kir Channel Blockages by Proflavine Derivatives via Multiple Modes of Interaction.

PubMed

Inanobe, Atsushi; Itamochi, Hideaki; Kurachi, Yoshihisa

2018-06-01

Many compounds inhibit tetrameric and pseudo-tetrameric cation channels by associating with the central cavity located in the middle of the membrane plane. They traverse the ion conduction pathway from the intracellular side and through access to the cavity. Previously, we reported that the bacteriostatic agent, proflavine, preferentially blocked a subset of inward rectifier K + (Kir) channels. However, the development of the inhibition of Kir1.1 by the compound was obviously different from that operating in Kir3.2 as a pore blocker. To gain mechanistic insights into the compound-channel interaction, we analyzed its chemical specificity, subunit selectivity, and voltage dependency using 13 different combinations of Kir-channel family members and 11 proflavine derivatives. The Kir-channel family members were classified into three groups: 1) Kir2.2, Kir3.x, Kir4.2, and Kir6.2Δ36, which exhibited Kir3.2-type inhibition (slow onset and recovery, irreversible, and voltage-dependent blockage); 2) Kir1.1 and Kir4.1/Kir5.1 (prompt onset and recovery, reversible, and voltage-independent blockage); and 3) Kir2.1, Kir2.3, Kir4.1, and Kir7.1 (no response). The degree of current inhibition depended on the combination of compounds and channels. Chimera between proflavine-sensitive Kir1.1 and -insensitive Kir4.1 revealed that the extracellular portion of Kir1.1 is crucial for the recognition of the proflavine derivative acrinol. In conclusion, preferential blockage of Kir-channel family members by proflavine derivatives is based on multiple modes of action. This raises the possibility of designing subunit-specific inhibitors. Copyright © 2018 by The Author(s).

Experimental Investigation of the Flow Field in a Transonic, Axial Flow Compressor with Respect to the Development of Blockage and Loss

NASA Technical Reports Server (NTRS)

Suder, Kenneth L.

1996-01-01

A detailed experimental investigation to understand and quantify the development of loss and blockage in the flow field of a transonic, axial flow compressor rotor has been undertaken. Detailed laser anemometer measurements were acquired upstream, within, and downstream of a transonic, axial compressor rotor operating at design and off-design conditions. The rotor was operated at 100%, 85%, 80%, and 60% of design speed which provided inlet relative Mach numbers at the blade tip of 1.48, 1.26, 1.18, and 0.89 respectively. At design speed the blockage is evaluated ahead of the rotor passage shock, downstream of the rotor passage shock, and near the trailing edge of the blade row. The blockage is evaluated in the core flow area as well as in the casing endwall region. Similarly at pm speed conditions for the cases of (1) where the rotor passage shock is much weaker than that at design speed and (2) where there is no rotor passage shock, the blockage and loss are evaluated and compared to the results at design speed. Specifically, the impact of the rotor passage shock on the blockage and loss development, pertaining to both the shock/boundary layer interactions and the shock/tip clearance flow interactions, is discussed. In addition, the blockage evaluated from the experimental data is compared to (1) an existing correlation of blockage development which was based on computational results, and (2) computational results on a limited basis. The results indicate that for this rotor the blockage in the endwall region is 2-3 times that of the core flow region and the blockage in the core flow region more than doubles when the shock strength is sufficient to separate the suction surface boundary layer. The distribution of losses in the care flow region indicate that the total loss is primarily comprised of the shock loss when the shock strength is not sufficient to separate the suction surface boundary layer. However, when the shock strength is sufficient to separate the

Transcription blockage by stable H-DNA analogs in vitro.

PubMed

Pandey, Shristi; Ogloblina, Anna M; Belotserkovskii, Boris P; Dolinnaya, Nina G; Yakubovskaya, Marianna G; Mirkin, Sergei M; Hanawalt, Philip C

2015-08-18

DNA sequences that can form unusual secondary structures are implicated in regulating gene expression and causing genomic instability. H-palindromes are an important class of such DNA sequences that can form an intramolecular triplex structure, H-DNA. Within an H-palindrome, the H-DNA and canonical B-DNA are in a dynamic equilibrium that shifts toward H-DNA with increased negative supercoiling. The interplay between H- and B-DNA and the fact that the process of transcription affects supercoiling makes it difficult to elucidate the effects of H-DNA upon transcription. We constructed a stable structural analog of H-DNA that cannot flip into B-DNA, and studied the effects of this structure on transcription by T7 RNA polymerase in vitro. We found multiple transcription blockage sites adjacent to and within sequences engaged in this triplex structure. Triplex-mediated transcription blockage varied significantly with changes in ambient conditions: it was exacerbated in the presence of Mn(2+) or by increased concentrations of K(+) and Li(+). Analysis of the detailed pattern of the blockage suggests that RNA polymerase is sterically hindered by H-DNA and has difficulties in unwinding triplex DNA. The implications of these findings for the biological roles of triple-stranded DNA structures are discussed. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Nearshore Hydroacoustic Seafloor Mapping In The German Bight (North Sea): Hydroacoustic Interpretation With And Without Classification

NASA Astrophysics Data System (ADS)

Hass, H. C.; Mielck, F.; Papenmeier, S.

2016-12-01

Nearshore habitats are in constant dynamic change. They need regular assessment and appropriate monitoring of areas of special interest. To accomplish this, hydroacoustic seabed characterization tools are applied to allow for cost-effective and efficient mapping of the seafloor. In this context single beam echosounders (SBES) systems provide a comprehensive view by analyzing the hardness and roughness characteristics of the seafloor. Interpolation between transect lines becomes necessary when gapless maps are needed. This study presents a simple method to process and visualize data recorded with RoxAnn (Sonavision, Edinburgh, UK) and similar SBES. Both, hardness and roughness data are merged to one combined parameter that receives a color code (RGB) according to the acoustic properties of the seafloor. This color information is then interpolated to obtain an area-wide map that provides unclassified and thus unbiased seabed information. The RGB color data can subsequently be used for classification and modeling purposes. Four surveys are shown from a morphologically complex nearshore area west of the island of Helgoland (SE North Sea). The area has complex textural and dynamic characteristics reaching from outcropping bedrock via sandy to muddy areas with mostly gradual transitions. RoxAnn data allow to discriminate all seafloor types that were suggested by ground-truth information (seafloor samples, video). The area appears to be fluctuating within certain limits. Sediment import (sand and fluid mud) paths can be reconstructed. Manually, six RoxAnn zones (RZ) were identified and left without hard boundaries to better match the seafloor types of the study site. The k-means fuzzy cluster analysis employed yields best results with 3 classes. We show that interpretations on the basis of largely non-classified, color-coded and interpolated data provide the best gain of information in the highest possible resolution. Classification with hard boundaries is necessary for

Blockage corrections for three-dimensional-flow closed-throat wind tunnels, with consideration of the effect of compressibility

NASA Technical Reports Server (NTRS)

Herriot, John G

1947-01-01

Theoretical blockage corrections are presented for a body of revolution and for a three-dimensional unswept wing in a circular or rectangular wind tunnel. The theory takes account of the effects of the wake and of the compressibility of the fluid, and is based on the assumption that the dimensions of the model are small in comparison with those of the tunnel throat. Formulas are given for correcting a number of the quantities, such as dynamic pressure and Mach number, measured in wind-tunnel tests. The report presents a summary and unification of the existing literature on the subject.

Ship Noise in the SW Indian Ocean Recorded by Ocean Bottom Seismic and Hydroacoustic Sensors

NASA Astrophysics Data System (ADS)

Barruol, G.; Dreo, R.; Fontaine, F. R.; Scholz, J. R.; Sigloch, K.

2016-12-01

In the frame of the RHUM-RUM project (Réunion Hotspot and Upper Mantle - Réunions Unterer Mantel, www.rhum-rum.net), a network of 57 ocean-bottom seismometers (OBS) has been installed on the ocean floor around La Réunion Island, but also on the neighbouring Southwest and Central Indian Ridges. The OBS were equipped by wide- and broad-band three-components seismic and hydroacoustic sensors. They were deployed in Nov. 2012, and depending on the configuration, they recorded for 8 to 13 months. Interestingly, part of the network was located beneath a NE-SW trending lane of very dense ship traffic connecting SE-Asia and the South-Atlantic region. By combining the vessel position - provided by AIS GPS data - and our geophysical data recorded on the ocean floor, we analyze the seismic and hydroacoustic ship signatures. From spectral analyzes, we show clear signals over the whole high-frequency range available from our instruments (between 1 and 50 Hz). The RHUM-RUM network covering latitude between 17 and 34° South, this allows to detect numerous vessels and to compare the noise characteristics (frequency content, polarization) of each vessel. We also investigate the possibility of using the polarization of the noise emitted by ships passing above an ocean-bottom seismometer, to help retrieving the orientation of the OBS horizontal components on the ocean floor in the geographic reference frame.

Numerical study of the influence of flow blockage on the aerodynamic coefficients of models in low-speed wind tunnels

NASA Astrophysics Data System (ADS)

Bui, V. T.; Kalugin, V. T.; Lapygin, V. I.; Khlupnov, A. I.

2017-11-01

With the use of ANSYS Fluent software and ANSYS ICEM CFD calculation grid generator, the flows past a wing airfoil, an infinite cylinder, and 3D blunted bodies located in the open and closed test sections of low-speed wind tunnels were calculated. The mathematical model of the flows included the Reynolds equations and the SST model of turbulence. It was found that the ratios between the aerodynamic coefficients in the test section and in the free (unbounded) stream could be fairly well approximated with a piecewise-linear function of the blockage factor, whose value weakly depended on the angle of attack. The calculated data and data gained in the analysis of previously reported experimental studies proved to be in a good agreement. The impact of the extension of the closed test section on the airfoil lift force is analyzed.

Optimization of Concurrent Deployments of the Juvenile Salmon Acoustic Telemetry System and Other Hydroacoustic Equipment at John Day Dam

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

Ploskey, Gene R.; Hughes, James S.; Khan, Fenton

The purpose of this report is to document the results of the acoustic optimization study conducted at John Day Dam during January and February 2008. The goal of the study was to optimize performance of the Juvenile Salmon Acoustic Telemetry System (JSATS) by determining deployment and data acquisition methods to minimize electrical and acoustic interference from various other acoustic sampling devices. Thereby, this would allow concurrent sampling by active and passive acoustic methods during the formal evaluations of the prototype surface flow outlets at the dam during spring and summer outmigration seasons for juvenile salmonids. The objectives for the optimizationmore » study at John Day Dam were to: 1. Design and test prototypes and provide a total needs list of pipes and trolleys to deploy JSATS hydrophones on the forebay face of the powerhouse and spillway. 2. Assess the effect on mean percentage decoded of JSATS transmissions from tags arrayed in the forebay and detected on the hydrophones by comparing: turbine unit OFF vs. ON; spill bay OPEN vs. CLOSED; dual frequency identification sonar (DIDSON) and acoustic Doppler current profiler (ADCP) both OFF vs. ON at a spill bay; and, fixed-aspect hydroacoustic system OFF vs. ON at a turbine unit and a spill bay. 3. Determine the relationship between fixed-aspect hydroacoustic transmit level and mean percentage of JSATS transmissions decoded. The general approach was to use hydrophones to listen for transmissions from JSATS tags deployed in vertical arrays in a series perpendicular to the face of the dam. We used acoustic telemetry equipment manufactured by Technologic and Sonic Concepts. In addition, we assessed old and new JSATS signal detectors and decoders and two different types of hydrophone baffling. The optimization study consisted of a suite of off/on tests. The primary response variable was mean percentage of tag transmissions decoded. We found that there was no appreciable adverse effect on mean

Hydroacoustic Evaluation of Juvenile Salmonid Passage and Distribution at Lookout Point Dam, 2010

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

Khan, Fenton; Johnson, Gary E.; Royer, Ida M.

2011-07-01

This report presents the results of an evaluation of juvenile salmonid passage and distribution at Lookout Point Dam (LOP) on the Middle Fork Willamette River. The study was conducted by the Pacific Northwest National Laboratory for the U.S. Army Corps of Engineers, Portland District (USACE). The goal of the study was to provide fish passage and distribution data to support decisions on long-term measures to enhance downstream passage at LOP and others dams in USACE’s Willamette Valley Project in response to the listing of Upper Willamette River Spring Chinook salmon (Oncorhynchus tshawytscha) and Upper Willamette River steelhead (O. mykiss) asmore » threatened under the Endangered Species Act. During the year-long study period - February 1, 2010 to January 31, 2011the objectives of the hydroacoustic evaluation of fish passage and distribution at LOP were to: 1. Estimate passage rates, run timing, horizontal distribution, and diel distribution at turbine penstock intakes for smolt-size fish. 2. Estimate passage rates, run timing and diel distribution at turbine penstock intakes for small-size fish. 3. Estimate passage rates and run timing at the regulating outlets for smolt-size fish. 4. Estimate vertical distribution of smolt-size fish in the forebay near the upstream face of the dam. The fixed-location hydroacoustic technique was used to accomplish the objectives of this study. Transducers (420 kHz) were deployed in each penstock intake, above each RO entrance, and on the dam face; a total of nine transducers (2 single-beam and 7 split-beam) were used. We summarize the findings from the hydroacoustic evaluation of juvenile salmonid passage and distribution at LOP during February 2010 through January 2011 as follows. • Fish passage rates for smolt-size fish (> ~90 mm) were highest during December-January and lowest in mid-summer through early fall. • During the entire study period, an estimated total of 142,463 fish ± 4,444 (95% confidence interval) smolt

Hydroacoustic Evaluation of Juvenile Salmonid Passage at The Dalles Dam Sluiceway, 2005

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

Johnson, Gary E.; Khan, Fenton; Hedgepeth, J

2006-06-01

The U.S. Army Corps of Engineers Portland District engaged the Pacific Northwest National Laboratory to evaluate fish passage at The Dalles Dam powerhouse in 2005. The goal of the study was to provide information on smolt passage that will inform decisions on long-term measures and operations to enhance sluiceway passage and reduce turbine passage to improve smolt survival at the dam. The study addressed one of the main programs dedicated to improving juvenile salmonid survival at The Dalles Dam: Surface Flow Bypass. The study objectives (see below) were met using a combination of hydroacoustic and hydraulic data. The study incorporatedmore » fixed-location hydroacoustic methods across the entire powerhouse, with especially intense sampling using multiple split-beam transducers at all sluiceway portals. We did not sample fish passage at the spillway in 2005. In the sluiceway nearfield, we used an acoustic camera to track fish movements. The fish data were interpreted with hydraulic data from a computational fluid dynamics (CFD) model. Fish passage data were collected in the framework of an “experiment” using a randomized block design (3-day treatments; two treatments) to compare two sluiceway operational configurations: Sluice 2+5 and Sluice 2+19 (six gates open for each configuration). Total project outflow was 76% of the 10-year average for spring and 71% of the 10-year average for summer. Based on these findings, we make the following recommendations: 1) The sluice should be operated 24 h/d from April until November. 2) Open six rather than three sluice gates to take advantage of the maximum hydraulic capacity of the sluiceway. 3) Open the three gates above the western-most operating main turbine unit and the three gates at MU 8 where turbine passage rates are relatively high. 4) Operate the turbine units below open sluice gates as a standard fish operations procedure. 5) Develop hydraulic and entrance enhancements to the sluiceway to tap the potential of

Validation of Blockage Interference Corrections in the National Transonic Facility

NASA Technical Reports Server (NTRS)

Walker, Eric L.

2007-01-01

A validation test has recently been constructed for wall interference methods as applied to the National Transonic Facility (NTF). The goal of this study was to begin to address the uncertainty of wall-induced-blockage interference corrections, which will make it possible to address the overall quality of data generated by the facility. The validation test itself is not specific to any particular modeling. For this present effort, the Transonic Wall Interference Correction System (TWICS) as implemented at the NTF is the mathematical model being tested. TWICS uses linear, potential boundary conditions that must first be calibrated. These boundary conditions include three different classical, linear. homogeneous forms that have been historically used to approximate the physical behavior of longitudinally slotted test section walls. Results of the application of the calibrated wall boundary conditions are discussed in the context of the validation test.

Enhancing the Contribution of the T-Stations of the IMS Hydroacoustic Network to IDC Processing and Tsunami Warning

DTIC Science & Technology

2010-09-01

Processing at the International Data Centre (IDC) classifies these signals into three types (T for underground- generated , H for in-water generated ...other hand, present the double disadvantages of a lower detection threshold for in-water propagated hydroacoustic signals and high sensitivity to the...the IMS because of their potential (deGroot-Hedlin, 2001) to detect water-borne signals from in-water explosions (H-phases) and crustal events (T

Strong transcription blockage mediated by R-loop formation within a G-rich homopurine–homopyrimidine sequence localized in the vicinity of the promoter

PubMed Central

Soo Shin, Jane Hae

2017-01-01

Abstract Guanine-rich (G-rich) homopurine–homopyrimidine nucleotide sequences can block transcription with an efficiency that depends upon their orientation, composition and length, as well as the presence of negative supercoiling or breaks in the non-template DNA strand. We report that a G-rich sequence in the non-template strand reduces the yield of T7 RNA polymerase transcription by more than an order of magnitude when positioned close (9 bp) to the promoter, in comparison to that for a distal (∼250 bp) location of the same sequence. This transcription blockage is much less pronounced for a C-rich sequence, and is not significant for an A-rich sequence. Remarkably, the blockage is not pronounced if transcription is performed in the presence of RNase H, which specifically digests the RNA strands within RNA–DNA hybrids. The blockage also becomes less pronounced upon reduced RNA polymerase concentration. Based upon these observations and those from control experiments, we conclude that the blockage is primarily due to the formation of stable RNA–DNA hybrids (R-loops), which inhibit successive rounds of transcription. Our results could be relevant to transcription dynamics in vivo (e.g. transcription ‘bursting’) and may also have practical implications for the design of expression vectors. PMID:28498974

Packet error rate analysis of decode-and-forward free-space optical cooperative networks in the presence of random link blockage

NASA Astrophysics Data System (ADS)

Zdravković, Nemanja; Cvetkovic, Aleksandra; Milic, Dejan; Djordjevic, Goran T.

2017-09-01

This paper analyses end-to-end packet error rate (PER) of a free-space optical decode-and-forward cooperative network over a gamma-gamma atmospheric turbulence channel in the presence of temporary random link blockage. Closed-form analytical expressions for PER are derived for the cases with and without transmission links being prone to blockage. Two cooperation protocols (denoted as 'selfish' and 'pilot-adaptive') are presented and compared, where the latter accounts for the presence of blockage and adapts transmission power. The influence of scintillation, link distance, average transmitted signal power, network topology and probability of an uplink and/or internode link being blocked are discussed when the destination applies equal gain combining. The results show that link blockage caused by obstacles can degrade system performance, causing an unavoidable PER floor. The implementation of the pilot-adaptive protocol improves performance when compared to the selfish protocol, diminishing internode link blockage and lowering the PER floor, especially for larger networks.

Hydroacoustic Recordings of Explosion-Induced Tremor at NW Rota-1 Volcano, Marianas

NASA Astrophysics Data System (ADS)

Caplan-Auerbach, J.; Dziak, R. P.; Lau, T. A.

2013-12-01

Hydroacoustic data recorded during the long-term eruption of NW Rota-1 submarine volcano (Marianas) reveal a wide variety of explosion and tremor signals. Data from a moored hydrophone deployed near the summit of NW Rota-1 from February 2009 to April 2010 confirm that NW Rota-1 was nearly continuously active during this time. Explosion acoustic signals have a wide range of frequencies: some carry energy that is bandlimited between 5-25 Hz while others show broadband signal strength between 5-200 Hz (even higher frequencies may be attenuated by the hydrophone's anti-aliasing filter at 220 Hz). The signal is observed to switch rapidly between low frequency and broadband explosion types. In many cases the explosion signals repeat at a high rate, with recurrence intervals between 0.1-0.5 seconds. In such instances the explosions blend into tremor, exhibiting a large number of spectral harmonics that we attribute to the Dirac comb effect. The presence of these harmonics indicates that explosion recurrence intervals are highly regular, although subtle gliding within the harmonic frequencies suggests that there is some variability in the timing between explosions. This suggests a strongly repeatable explosion source. The frequency of explosions at NW Rota-1 is confirmed by ROV observations of eruption plume dynamics (Chadwick et al., 2008; Deardorff et al., 2008). We also observe a strong low-frequency (< 5 Hz) tremor signal that does not correlate with the explosion tremor, as well as strongly harmonic tremor that is not obviously composed of repeating explosions. These signals may reflect processes deeper within the conduit, yet still capable of coupling into the water column. Video footage collected during ROV dives in 2009 shows multiple instances in which the ground is observed to move, but these signals do not clearly correlate with hydroacoustic pulses. Deeper study into the source of these signals requires seismic instrumentation on and around NW Rota-1.

Propeller Analysis Using RANS/BEM Coupling Accounting for Blade Blockage

DTIC Science & Technology

2015-07-04

described. Estimates of the importance of the blade blockage effect are obtained by analyzing the propeller of the well-known KRISO container ship (KCS...2 and 3 were applied to the KRISO Container Ship (KCS), a test case that has often been reported in the scientific literature, in particular the

Strong transcription blockage mediated by R-loop formation within a G-rich homopurine-homopyrimidine sequence localized in the vicinity of the promoter.

PubMed

Belotserkovskii, Boris P; Soo Shin, Jane Hae; Hanawalt, Philip C

2017-06-20

Guanine-rich (G-rich) homopurine-homopyrimidine nucleotide sequences can block transcription with an efficiency that depends upon their orientation, composition and length, as well as the presence of negative supercoiling or breaks in the non-template DNA strand. We report that a G-rich sequence in the non-template strand reduces the yield of T7 RNA polymerase transcription by more than an order of magnitude when positioned close (9 bp) to the promoter, in comparison to that for a distal (∼250 bp) location of the same sequence. This transcription blockage is much less pronounced for a C-rich sequence, and is not significant for an A-rich sequence. Remarkably, the blockage is not pronounced if transcription is performed in the presence of RNase H, which specifically digests the RNA strands within RNA-DNA hybrids. The blockage also becomes less pronounced upon reduced RNA polymerase concentration. Based upon these observations and those from control experiments, we conclude that the blockage is primarily due to the formation of stable RNA-DNA hybrids (R-loops), which inhibit successive rounds of transcription. Our results could be relevant to transcription dynamics in vivo (e.g. transcription 'bursting') and may also have practical implications for the design of expression vectors. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

1300-m-high rising bubbles from mud volcanoes at 2080 m in the Black Sea: Hydroacoustic characteristics and temporal variability

NASA Astrophysics Data System (ADS)

Greinert, Jens; Artemov, Yuriy; Egorov, Viktor; De Batist, Marc; McGinnis, Daniel

2006-04-01

deep marine environments. To better understand how a methane bubble (gas analyses of the pore water and gas hydrate gave 99.4% methane) can rise so high without dissolving, we applied a recently developed bubble dissolution model that takes into account a decreased mass transfer due to an immediately formed gas-hydrate rim. Using the hydroacoustically determined bubble rising speeds (19-22 cm/s at the bottom; 12-14 cm/s at the flare top) and the relation between the rising speed of 'dirty'/gas hydrate rimmed bubbles and the bubble size, we could validate that a gas-hydrate-rimmed bubble with a diameter of 9 mm could survive the 1300-m-rise through the water column, before it is finally dissolved. A diameter of about 9 mm is reasonable for bubbles released at seep sites and the coincidence between the observed bubble rising speed and the model approach of a 9-mm bubble supports the assumption of gas-hydrate-rimmed bubbles.

Hydroacoustics for the discovery and quantification of Nassau grouper ( Epinephelus striatus) spawning aggregations

NASA Astrophysics Data System (ADS)

Egerton, J. P.; Johnson, A. F.; Le Vay, L.; McCoy, C. M.; Semmens, B. X.; Heppell, S. A.; Turner, J. R.

2017-06-01

Fish spawning aggregations (FSAs) are vital life-history events that need to be monitored to determine the health of aggregating populations; this is especially true of the endangered Nassau grouper ( Epinephelus striatus). Hydroacoustics were used to locate Nassau grouper FSAs at sites on the west end of Little Cayman (LCW), and east ends of Grand Cayman (GCE) and Cayman Brac (CBE). Fish abundance and biomass at each FSA were estimated via echo integration and FSA extent. Acoustic mean fish abundance estimates (±SE) on the FSA at LCW (893 ± 459) did not differ significantly from concurrent SCUBA estimates (1150 ± 75). Mean fish densities (number 1000 m-3) were significantly higher at LCW (33.13 ± 5.62) than at the other sites (GCE: 7.01 ± 2.1, CBE: 4.61 ± 1.16). We investigate different acoustic post-processing options to obtain target strength (TS), and we examine the different TS to total length (TL) formulas available. The SCUBA surveys also provided measures of TL through the use of laser callipers allowing development of an in situ TS to TL formula for Nassau grouper at the LCW FSA. Application of this formula revealed mean fish TL was significantly higher at LCW (65.4 ± 0.7 cm) than GCE (60.7 ± 0.4 cm), but not CBE (61.1 ± 2.5 cm). Use of the empirical TS to TL formula resulted in underestimation of fish length in comparison with diver measurements, highlighting the benefits of secondary length data and deriving specific TS to TL formulas for each population. FSA location examined with reference to seasonal marine protected areas (Designated Grouper Spawning Areas) showed FSAs were partially outside these areas at GCE and very close to the boundary at CBE. As FSAs often occur at the limits of safe diving operations, hydroacoustic technology provides an alternative method to monitor and inform future management of aggregating fish species.

On Blockage Corrections for Two-dimensional Wind Tunnel Tests Using the Wall-pressure Signature Method

NASA Technical Reports Server (NTRS)

Allmaras, S. R.

1986-01-01

The Wall-Pressure Signature Method for correcting low-speed wind tunnel data to free-air conditions has been revised and improved for two-dimensional tests of bluff bodies. The method uses experimentally measured tunnel wall pressures to approximately reconstruct the flow field about the body with potential sources and sinks. With the use of these sources and sinks, the measured drag and tunnel dynamic pressure are corrected for blockage effects. Good agreement is obtained with simpler methods for cases in which the blockage corrections were about 10% of the nominal drag values.

Comparison of computational results of the SABRE LMFBR pin bundle blockage code with data from well-instrumented out-of-pile test bundles (THORS bundles 3A and 5A)

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

Dearing, J.F.

The Subchannel Analysis of Blockages in Reactor Elements (SABRE) computer code, developed by the United Kingdom Atomic Energy Authority, is currently the only practical tool available for performing detailed analyses of velocity and temperature fields in the recirculating flow regions downstream of blockages in liquid-metal fast breeder reactor (LMFBR) pin bundles. SABRE is a subchannel analysis code; that is, it accurately represents the complex geometry of nuclear fuel pins arranged on a triangular lattice. The results of SABRE computational models are compared here with temperature data from two out-of-pile 19-pin test bundles from the Thermal-Hydraulic Out-of-Reactor Safety (THORS) Facility atmore » Oak Ridge National Laboratory. One of these bundles has a small central flow blockage (bundle 3A), while the other has a large edge blockage (bundle 5A). Values that give best agreement with experiment for the empirical thermal mixing correlation factor, FMIX, in SABRE are suggested. These values of FMIX are Reynolds-number dependent, however, indicating that the coded turbulent mixing correlation is not appropriate for wire-wrap pin bundles.« less

Sensitivity of fish density estimates to standard analytical procedures applied to Great Lakes hydroacoustic data

USGS Publications Warehouse

Kocovsky, Patrick M.; Rudstam, Lars G.; Yule, Daniel L.; Warner, David M.; Schaner, Ted; Pientka, Bernie; Deller, John W.; Waterfield, Holly A.; Witzel, Larry D.; Sullivan, Patrick J.

2013-01-01

Standardized methods of data collection and analysis ensure quality and facilitate comparisons among systems. We evaluated the importance of three recommendations from the Standard Operating Procedure for hydroacoustics in the Laurentian Great Lakes (GLSOP) on density estimates of target species: noise subtraction; setting volume backscattering strength (Sv) thresholds from user-defined minimum target strength (TS) of interest (TS-based Sv threshold); and calculations of an index for multiple targets (Nv index) to identify and remove biased TS values. Eliminating noise had the predictable effect of decreasing density estimates in most lakes. Using the TS-based Sv threshold decreased fish densities in the middle and lower layers in the deepest lakes with abundant invertebrates (e.g., Mysis diluviana). Correcting for biased in situ TS increased measured density up to 86% in the shallower lakes, which had the highest fish densities. The current recommendations by the GLSOP significantly influence acoustic density estimates, but the degree of importance is lake dependent. Applying GLSOP recommendations, whether in the Laurentian Great Lakes or elsewhere, will improve our ability to compare results among lakes. We recommend further development of standards, including minimum TS and analytical cell size, for reducing the effect of biased in situ TS on density estimates.

Validation of attenuation, beam blockage, and calibration estimation methods using two dual polarization X band weather radars

NASA Astrophysics Data System (ADS)

Diederich, M.; Ryzhkov, A.; Simmer, C.; Mühlbauer, K.

2011-12-01

The amplitude a of radar wave reflected by meteorological targets can be misjudged due to several factors. At X band wavelength, attenuation of the radar beam by hydro meteors reduces the signal strength enough to be a significant source of error for quantitative precipitation estimation. Depending on the surrounding orography, the radar beam may be partially blocked when scanning at low elevation angles, and the knowledge of the exact amount of signal loss through beam blockage becomes necessary. The phase shift between the radar signals at horizontal and vertical polarizations is affected by the hydrometeors that the beam travels through, but remains unaffected by variations in signal strength. This has allowed for several ways of compensating for the attenuation of the signal, and for consistency checks between these variables. In this study, we make use of several weather radars and gauge network measuring in the same area to examine the effectiveness of several methods of attenuation and beam blockage corrections. The methods include consistency checks of radar reflectivity and specific differential phase, calculation of beam blockage using a topography map, estimating attenuation using differential propagation phase, and the ZPHI method proposed by Testud et al. in 2000. Results show the high effectiveness of differential phase in estimating attenuation, and potential of the ZPHI method to compensate attenuation, beam blockage, and calibration errors.

Measuring real-time streamflow using emerging technologies: Radar, hydroacoustics, and the probability concept

NASA Astrophysics Data System (ADS)

Fulton, John; Ostrowski, Joseph

2008-07-01

SummaryForecasting streamflow during extreme hydrologic events such as floods can be problematic. This is particularly true when flow is unsteady, and river forecasts rely on models that require uniform-flow rating curves to route water from one forecast point to another. As a result, alternative methods for measuring streamflow are needed to properly route flood waves and account for inertial and pressure forces in natural channels dominated by nonuniform-flow conditions such as mild water surface slopes, backwater, tributary inflows, and reservoir operations. The objective of the demonstration was to use emerging technologies to measure instantaneous streamflow in open channels at two existing US Geological Survey streamflow-gaging stations in Pennsylvania. Surface-water and instream-point velocities were measured using hand-held radar and hydroacoustics. Streamflow was computed using the probability concept, which requires velocity data from a single vertical containing the maximum instream velocity. The percent difference in streamflow at the Susquehanna River at Bloomsburg, PA ranged from 0% to 8% with an average difference of 4% and standard deviation of 8.81 m 3/s. The percent difference in streamflow at Chartiers Creek at Carnegie, PA ranged from 0% to 11% with an average difference of 5% and standard deviation of 0.28 m 3/s. New generation equipment is being tested and developed to advance the use of radar-derived surface-water velocity and instantaneous streamflow to facilitate the collection and transmission of real-time streamflow that can be used to parameterize hydraulic routing models.

Measuring real-time streamflow using emerging technologies: Radar, hydroacoustics, and the probability concept

USGS Publications Warehouse

Fulton, J.; Ostrowski, J.

2008-01-01

Forecasting streamflow during extreme hydrologic events such as floods can be problematic. This is particularly true when flow is unsteady, and river forecasts rely on models that require uniform-flow rating curves to route water from one forecast point to another. As a result, alternative methods for measuring streamflow are needed to properly route flood waves and account for inertial and pressure forces in natural channels dominated by nonuniform-flow conditions such as mild water surface slopes, backwater, tributary inflows, and reservoir operations. The objective of the demonstration was to use emerging technologies to measure instantaneous streamflow in open channels at two existing US Geological Survey streamflow-gaging stations in Pennsylvania. Surface-water and instream-point velocities were measured using hand-held radar and hydroacoustics. Streamflow was computed using the probability concept, which requires velocity data from a single vertical containing the maximum instream velocity. The percent difference in streamflow at the Susquehanna River at Bloomsburg, PA ranged from 0% to 8% with an average difference of 4% and standard deviation of 8.81 m3/s. The percent difference in streamflow at Chartiers Creek at Carnegie, PA ranged from 0% to 11% with an average difference of 5% and standard deviation of 0.28 m3/s. New generation equipment is being tested and developed to advance the use of radar-derived surface-water velocity and instantaneous streamflow to facilitate the collection and transmission of real-time streamflow that can be used to parameterize hydraulic routing models.

Effects of percentage of blockage and flameholder downstream counterbores on lean combustion limits of premixed, prevaporized propane-air mixture

NASA Technical Reports Server (NTRS)

Fernandez, M. A. B.

1983-01-01

Lean combustion limits were determined for a premixed prevaporized propane air mixture with flat plate flame stabilizers. Experiments were conducted in a constant area flame tube combustor utilizing flameholders of varying percentages of blockage and downstream counterbores. Combustor inlet air velocity at ambient conditions was varied from 4 to 9 meters per second. Flameholders with a center hole and four half holes surrounding it were tested with 63, 73, and 85 percent blockage and counterbore diameters of 112 and 125 percent of the thru hole diameter, in addition to the no counterbore configuration. Improved stability was obtained by using counterbore flameholders and higher percentages of blockage. Increases in mixture velocity caused the equivalence ratio at blowout to increase in all cases.

Background Acoustic Noise Models for the IMS Hydroacoustic Stations

DTIC Science & Technology

2010-09-01

noise models based on data from the 60’s and 70’s ( Urick , 1983). In some ocean basins, noise levels in the monitoring band (1-100 Hz) have risen 15...the 60?s and 70?s ( Urick , 1983). In some ocean basins, noise levels in the monitoring band (1-100 Hz) have risen 15 dB since the 1960?s. To address this...from Urick , 1983. 2010 Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring Technologies 542 To address this issue and provide

Swirl, Expansion Ratio and Blockage Effects on Confined Turbulent Flow. M.S. Thesis

NASA Technical Reports Server (NTRS)

Scharrer, G. L.

1982-01-01

A confined jet test facility, a swirles, flow visualization equipment, five-hole pitot probe instrumentation; flow visualization; and effects of swirl on open-ended flows, of gradual expansion on open-ended flows, and blockages of flows are addressed.

Mechanism of Adenomatous Polyposis Coli (APC)-mediated Blockage of Longpatch Base Excision Repair†

PubMed Central

Jaiswal, Aruna S.; Balusu, Ramesh; Armas, Melissa L.; Kundu, Chanakya N.; Narayan, Satya

2008-01-01

Recently, we found an interaction between adenomatous polyposis coli (APC) and DNA polymerase β (pol-β) and showed that APC blocks strand-displacement synthesis of long-patch base excision repair (LP-BER) however, the mechanism is not clear. Using an in vivo LP-BER assay system, we now show that the LP-BER is higher in APC−/− cells than in APC+/+ cells. In addition to pol-β, the pull-down experiments showed that the full-length APC also interacted with flap endonuclease 1 (Fen-1). To further characterize the interaction of APC with pol-β and Fen-1, we performed a domain-mapping of APC and found that both pol-β and Fen-1 interact with a 138-amino acids peptide from the APC at the DRI-domain. Our functional assays showed that APC blocks pol-β-mediated 1-nucleotide (1-nt) as well as strand-displacement synthesis of reduced abasic, nicked-, or 1-nt gapped-DNA substrates. Our further studies demonstrated that APC blocks 5′-flap endonuclease as well as 5′-3′ exonuclease activity of Fen-1 resulting in the blockage of LP-BER. From these results we concluded that APC can have three different effects in the LP-BER pathway. First, APC can block pol-β-mediated 1-nt incorporation and strand-displacement synthesis. Second, APC can block LP-BER by blocking coordinated formation and removal of the strand-displaced flap. Third, APC can block LP-BER by blocking “Hit and Run” synthesis. These studies will have important implications of APC in DNA damage-induced carcinogenesis and chemoprevention. PMID:17176113

On the preventive management of sediment-related sewer blockages: a combined maintenance and routing optimization approach.

PubMed

Fontecha, John E; Akhavan-Tabatabaei, Raha; Duque, Daniel; Medaglia, Andrés L; Torres, María N; Rodríguez, Juan Pablo

In this work we tackle the problem of planning and scheduling preventive maintenance (PM) of sediment-related sewer blockages in a set of geographically distributed sites that are subject to non-deterministic failures. To solve the problem, we extend a combined maintenance and routing (CMR) optimization approach which is a procedure based on two components: (a) first a maintenance model is used to determine the optimal time to perform PM operations for each site and second (b) a mixed integer program-based split procedure is proposed to route a set of crews (e.g., sewer cleaners, vehicles equipped with winches or rods and dump trucks) in order to perform PM operations at a near-optimal minimum expected cost. We applied the proposed CMR optimization approach to two (out of five) operative zones in the city of Bogotá (Colombia), where more than 100 maintenance operations per zone must be scheduled on a weekly basis. Comparing the CMR against the current maintenance plan, we obtained more than 50% of cost savings in 90% of the sites.

Microscopic model of road capacity for highway systems in port based metropolitan areas.

DOT National Transportation Integrated Search

2011-03-01

In this report, we present our approach to use microscopic modeling to assess : highway traffic mobility during lane blockage situation. A test microscopic model using : ARENA software is developed. In this model, we specifically aim to simulate the ...

Auditory cortical plasticity induced by intracortical microstimulation under pharmacological blockage of inhibitory synapses.

PubMed

Yokota, R; Takahashi, H; Funamizu, A; Uchihara, M; Suzurikawa, J; Kanzaki, R

2006-01-01

Electrical stimulation that can reorganize our neural system has a potential for promising neurorehabilitation. We previously demonstrated that temporally controlled intracortical microstimulation (ICMS) could induce the spike time-dependant plasticity and modify tuning properties of cortical neurons as desired. A 'pairing' ICMS following tone-induced excitatory post-synaptic potentials (EPSPs) produced potentiation in response to the paired tones, while an 'anti-pairing' ICMS preceding the tone-induced EPSPs resulted in depression. However, the conventional ICMS affected both excitatory and inhibitory synapses, and thereby could not quantify net excitatory synaptic effects. In the present work, we evaluated the ICMS effects under a pharmacological blockage of inhibitory inputs. The pharmacological blockage enhanced the ICMS effects, suggesting that inhibitory inputs determine a plastic degree of the neural system. Alternatively, the conventional ICMS had an inadequate timing to control excitatory synaptic inputs, because inhibitory synapse determined the latency of total neural inputs.

Numerical Modelling of circulation and internal tides on the Crozet plateau in support of the IMS/CTBTO hydroacoustic installation HA04

NASA Astrophysics Data System (ADS)

Lyard, Florent Henri; Zampolli, Mario; Marsaleix, Patrick

2014-05-01

Hydrophone stations of the Comprehensive Nuclear-Test-Ban Organisation (CTBTO) International Monitoring System (IMS), with the exception of one in Australia, comprise two triplets of submerged moored hydrophones, one North and one South of the island from which the respective system is deployed. Triplet distances vary approximately between 50 - 100 km kilometres from the island, with each triplet connected to the receiving shore equipment by fibre-optic submarine data cables. Once deployed, the systems relay underwater acoustic waveforms in the band 1 - 100 Hz in real time to Vienna via a shore based satellite link. The design life of hydroacoustic stations is at least 20 years, without need for any maintenance of the underwater system. The re-establishment of hydrophone monitoring station HA04 at Crozet (French Southern and Antarctic Territories) in the South-Western Indian Ocean is currently being investigated. The highly dynamic ocean environment at Crozet is governed by strong winds and generally high sea states at the surface, local circulation emanating from the sub-Antarctic front (SAF) and the Agulhas return current (ARC), moderate surface tides and strong internal tides. Deploying the submarine cables and triplets in such an environment requires careful evaluation of all risks and in particular the minimization of the exposure of the deployed system to excessively strong currents. This issue has been addressed by two studies which are briefly introduced here. In the first study, a linear spectral model was used to study and characterize the barotropic tide-driven currents on the Crozet plateau in three spatial dimensions. The M2 semi-diurnal component was shown to dominate in the area, driving sizeable internal tides. The estimate was quantitatively and spatially refined in the second study, in which a time stepping model was used taking into account the local ocean climatology and stratification, as well as the interplay between the seasonally varying

Implosion Source Development and Diego Garcia Reflections

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

Harben, P E; Boro, C

2001-06-01

Calibration of hydroacoustic stations for nuclear explosion monitoring is important for increasing monitoring capability and confidence from newly installed stations and from existing stations. Past work at Ascension Island has shown that ship-towed airguns can be effectively used for local calibrations such as sensor location, amplitude and phase response, and T-phase coupling in the case of T-phase stations. At regional and ocean-basin distances from a station, the calibration focus is on acoustic travel time, transmission loss, bathymetric shadowing, diffraction, and reflection as recorded at a particular station. Such station calibrations will lead to an overall network calibration that seeks tomore » maximize detection, location, and discrimination capability of events with acoustic signatures. Active-source calibration of hydroacoustic stations at regional and ocean-basin scales has not been attempted to date, but we have made significant headway addressing how such calibrations could be accomplished. We have developed an imploding sphere source that can be used instead of explosives on research and commercial vessels without restriction. The imploding sphere has been modeled using the Lawrence Livermore National Laboratory hydrodynamic code CALE and shown to agree with field data. The need for boosted energy in the monitoring band (2-100 Hz) has led us to develop a 5-sphere implosion device that was tested in the Pacific Ocean earlier this year. Boosting the energy in the monitoring band can be accomplished by a combination of increasing the implosion volume (i.e. the 5-sphere device) and imploding at shallower depths. Although active source calibrations will be necessary at particular locations and for particular objectives, the newly installed Diego Garcia station in the Indian Ocean has shown that earthquakes can be used to help understand regional blockages and the locations responsible for observed hydroacoustic reflections. We have analyzed several

Hydroacoustic forcing function modeling using DNS database

NASA Technical Reports Server (NTRS)

Zawadzki, I.; Gershfield, J. L.; Na, Y.; Wang, M.

1996-01-01

A wall pressure frequency spectrum model (Blake 1971 ) has been evaluated using databases from Direct Numerical Simulations (DNS) of a turbulent boundary layer (Na & Moin 1996). Good agreement is found for moderate to strong adverse pressure gradient flows in the absence of separation. In the separated flow region, the model underpredicts the directly calculated spectra by an order of magnitude. The discrepancy is attributed to the violation of the model assumptions in that part of the flow domain. DNS computed coherence length scales and the normalized wall pressure cross-spectra are compared with experimental data. The DNS results are consistent with experimental observations.

Experimental and numerical investigation on heat transfer augmentation in a circular tube under forced convection with annular differential blockages/inserts

NASA Astrophysics Data System (ADS)

Waghole, D. R.

2018-06-01

Investigation on heat transfer by generating turbulence in the fluid stream inside the circular tube is an innovative area of research for researchers. Hence, many techniques are been investigated and adopted for enhancement of heat transfer rate to reduce the size and the cost of the heat exchanger/circular tube. In the present study the effect of differential solid ring inserts /turbulators on heat transfer, friction factor of heat exchanger/circular tube was evaluated through experimentally and numerically. The experiments were conducted in range of 3000 ≤Re≤ 6500 and annular blockages 0 ≤ɸ≤50 %. The heat transfer rate was higher for differential combination of inserts as compared to tube fitted with uniform inserts. The maximum heat transfer was obtained by the use of differential metal circular ring inserts/blockages. From this study, Nusselt number, friction factor and enhancement factor are found as 2.5-3.5 times, 12% - 50.5% and 155% - 195%, respectively with water. Finally new possible correlations for predicting heat transfer and friction factor in the flow of water through the circular tube with differential blockages/inserts are proposed.

Acoustic Propagation Modeling for Marine Hydro-Kinetic Applications

NASA Astrophysics Data System (ADS)

Johnson, C. N.; Johnson, E.

2014-12-01

The combination of riverine, tidal, and wave energy have the potential to supply over one third of the United States' annual electricity demand. However, in order to deploy and test prototypes, and commercial installations, marine hydrokinetic (MHK) devices must meet strict regulatory guidelines that determine the maximum amount of noise that can be generated and sets particular thresholds for determining disturbance and injury caused by noise. An accurate model for predicting the propagation of a MHK source in a real-life hydro-acoustic environment has been established. This model will help promote the growth and viability of marine, water, and hydrokinetic energy by confidently assuring federal regulations are meet and harmful impacts to marine fish and wildlife are minimal. Paracousti, a finite difference solution to the acoustic equations, was originally developed for sound propagation in atmospheric environments and has been successfully validated for a number of different geophysical activities. The three-dimensional numerical implementation is advantageous over other acoustic propagation techniques for a MHK application where the domains of interest have complex 3D interactions from the seabed, banks, and other shallow water effects. A number of different cases for hydro-acoustic environments have been validated by both analytical and numerical results from canonical and benchmark problems. This includes a variety of hydrodynamic and physical environments that may be present in a potential MHK application including shallow and deep water, sloping, and canyon type bottoms, with varying sound speed and density profiles. With the model successfully validated for hydro-acoustic environments more complex and realistic MHK sources from turbines and/or arrays can be modeled.

A Tool for Modelling the Probability of Landslides Impacting Road Networks

NASA Astrophysics Data System (ADS)

Taylor, Faith E.; Santangelo, Michele; Marchesini, Ivan; Malamud, Bruce D.; Guzzetti, Fausto

2014-05-01

Triggers such as earthquakes or heavy rainfall can result in hundreds to thousands of landslides occurring across a region within a short space of time. These landslides can in turn result in blockages across the road network, impacting how people move about a region. Here, we show the development and application of a semi-stochastic model to simulate how landslides intersect with road networks during a triggered landslide event. This was performed by creating 'synthetic' triggered landslide inventory maps and overlaying these with a road network map to identify where road blockages occur. Our landslide-road model has been applied to two regions: (i) the Collazzone basin (79 km2) in Central Italy where 422 landslides were triggered by rapid snowmelt in January 1997, (ii) the Oat Mountain quadrangle (155 km2) in California, USA, where 1,350 landslides were triggered by the Northridge Earthquake (M = 6.7) in January 1994. For both regions, detailed landslide inventory maps for the triggered events were available, in addition to maps of landslide susceptibility and road networks of primary, secondary and tertiary roads. To create 'synthetic' landslide inventory maps, landslide areas (AL) were randomly selected from a three-parameter inverse gamma probability density function, consisting of a power law decay of about -2.4 for medium and large values of AL and an exponential rollover for small values of AL. The number of landslide areas selected was based on the observed density of landslides (number of landslides km-2) in the triggered event inventories. Landslide shapes were approximated as ellipses, where the ratio of the major and minor axes varies with AL. Landslides were then dropped over the region semi-stochastically, conditioned by a landslide susceptibility map, resulting in a synthetic landslide inventory map. The originally available landslide susceptibility maps did not take into account susceptibility changes in the immediate vicinity of roads, therefore

Slotted-wall research with disk and parachute models in a low-speed wind tunnel

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

Macha, J.M.; Buffington, R.J.; Henfling, J.L.

1990-01-01

An experimental investigation of slotted-wall blockage interference has been conducted using disk and parachute models in a low speed wind tunnel. Test section open area ratio, model geometric blockage ratio, and model location along the length of the test section were systematically varied. Resulting drag coefficients were compared to each other and to interference-free measurements obtained in a much larger wind tunnel where the geometric blockage ratio was less than 0.0025. 9 refs., 10 figs.

A Dynamic Model for the Evaluation of Aircraft Engine Icing Detection and Control-Based Mitigation Strategies

NASA Technical Reports Server (NTRS)

Simon, Donald L.; Rinehart, Aidan W.; Jones, Scott M.

2017-01-01

Aircraft flying in regions of high ice crystal concentrations are susceptible to the buildup of ice within the compression system of their gas turbine engines. This ice buildup can restrict engine airflow and cause an uncommanded loss of thrust, also known as engine rollback, which poses a potential safety hazard. The aviation community is conducting research to understand this phenomena, and to identify avoidance and mitigation strategies to address the concern. To support this research, a dynamic turbofan engine model has been created to enable the development and evaluation of engine icing detection and control-based mitigation strategies. This model captures the dynamic engine response due to high ice water ingestion and the buildup of ice blockage in the engines low pressure compressor. It includes a fuel control system allowing engine closed-loop control effects during engine icing events to be emulated. The model also includes bleed air valve and horsepower extraction actuators that, when modulated, change overall engine operating performance. This system-level model has been developed and compared against test data acquired from an aircraft turbofan engine undergoing engine icing studies in an altitude test facility and also against outputs from the manufacturers customer deck. This paper will describe the model and show results of its dynamic response under open-loop and closed-loop control operating scenarios in the presence of ice blockage buildup compared against engine test cell data. Planned follow-on use of the model for the development and evaluation of icing detection and control-based mitigation strategies will also be discussed. The intent is to combine the model and control mitigation logic with an engine icing risk calculation tool capable of predicting the risk of engine icing based on current operating conditions. Upon detection of an operating region of risk for engine icing events, the control mitigation logic will seek to change the

Three-dimensional model of hydro acoustic channel for research MIMO systems

NASA Astrophysics Data System (ADS)

Fedosov, V. P.; Lomakina, A. V.; Legin, A. A.; Voronin, V. V.

2017-05-01

Currently, wireless hydroacoustic modems are actively being developed, which are used to provide efficient data transmission in the hydroacoustic channel. Such kind of developments are relevant for today, as they are used in various fields of science and fields of activity. An example is the connection with underwater vehicles for scientific, research, search and rescue purposes. Development of this kind of communication systems (modems) is a difficult task, as signal propagation is affected by various factors. As a result, the transfer characteristic changes with time, thereby imposing restrictions on the acoustic communication channel. In this regard, the researchers began the task of further study sonar environment and get a detailed mathematical description of the underwater channel. For this, a huge number of field tests were conducted, aimed at studying the underwater acoustic environment. However, the results of the research are always limited by the conditions in which the test took place. Therefore, it is not always possible to apply these results to the required conditions. All of the above features do not allow you to create some kind of a commonly accepted model for the acoustic channel, as studies based on experiments, collected in localized environments without generalizations. This paper presents, the three-dimensional model of the sonar channel for MIMO systems in the coastal zone, based on the acoustic signal propagation characteristics in the presence of multiple paths, the influence of the Doppler effect (as a result of mobile and / or base station traffic), in terms of signal attenuation, receiver characteristics influence and Transmitting antenna, etc.

Value of the Application of Neuroendoscope in the Treatment of Ventriculoperitoneal Shunt Blockage.

PubMed

Wei, Quantang; Xu, Yimin; Peng, Kaiwen; Qi, Songtao; Peng, Yuping; Ji, Huangyi; Li, Yu; Qiu, Mingxing; Ying, Yanyi; Qiu, Xiaoyu

2018-05-10

To explore the value of the application of neuroendoscope techniques in the treatment of ventriculoperitoneal shunt blockage. Our study included 3 plans for revision surgeries for ventriculoperitoneal shunt blockage. In Plan A, the choroid plexus or ependyma that grew inside the ventricular catheter was completely removed. In Plan B, the terminal part of the ventricular catheter was clipped and removed. In Plan C, the ventricular catheter was carefully extracted with the assistance of neuroendoscope, and the tissues that blocked the catheter were removed. Then, the ventricular catheter was reinserted into the lateral ventricle. The side holes of the tube may be blocked by cerebral tissue, granulation tissue, newly formed blood vessels, choroid plexus or ependymal. Five patients successfully underwent the Plan A revision surgery. Eight patients underwent the Plan B revision surgery. The remaining 22 patients underwent the Plan C revision surgery. After the operation, 34 patients exhibited relieved symptoms with high intracranial pressure. In all patients, the shunts became unobstructed. Neuroendoscope techniques can be used to reveal the various causes of shunt obstruction. Any attempt to extract the tube should be performed with the assistance of neuroendoscope. There are 3 revision surgery plans for a blocked catheter. These revision surgeries for shunt obstruction are mentioned for the first time in the literature. These methods could reduce the operation time, the incidence of intraventricular hemorrhage and the risk of infection. Copyright © 2018. Published by Elsevier Inc.

The pepper's natural ingredient capsaicin induces autophagy blockage in prostate cancer cells

PubMed Central

Ramos-Torres, Ágata; Bort, Alicia; Morell, Cecilia; Rodríguez-Henche, Nieves; Díaz-Laviada, Inés

2016-01-01

Capsaicin, the pungent ingredient of red hot chili peepers, has been shown to have anti-cancer activities in several cancer cells, including prostate cancer. Several molecular mechanisms have been proposed on its chemopreventive action, including ceramide accumulation, endoplasmic reticulum stress induction and NFκB inhibition. However, the precise mechanisms by which capsaicin exerts its anti-proliferative effect in prostate cancer cells remain questionable. Herein, we have tested the involvement of autophagy on the capsaicin mechanism of action on prostate cancer LNCaP and PC-3 cells. The results showed that capsaicin induced prostate cancer cell death in a time- and concentration-dependent manner, increased the levels of microtubule-associated protein light chain 3-II (LC3-II, a marker of autophagy) and the accumulation of the cargo protein p62 suggesting an autophagy blockage. Moreover, confocal microscopy revealed that capsaicin treatment increased lysosomes which co-localized with LC3 positive vesicles in a similar extent to that produced by the lysosomal protease inhibitors E64 and pepstatin pointing to an autophagolysosomes breakdown inhibition. Furthermore, we found that capsaicin triggered ROS generation in cells, while the levels of ROS decreased with N-acetyl-cysteine (NAC), a ROS scavenger. Co-treatment of cells with NAC and capsaicin abrogated the effects of capsaicin on autophagy and cell death. Normal prostate PNT2 and RWPE-1 cells were more resistant to capsaicin-induced cytotoxicity and did not accumulate p62 protein. Taken together, these results suggest that ROS-mediated capsaicin-induced autophagy blockage contributes to antiproliferation in prostate cancer cells, which provides new insights into the anticancer molecular mechanism of capsaicin. PMID:26625315

AREVA Team Develops Sump Strainer Blockage Solution for PWRs

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

Phan, Ray

2006-07-01

The purpose of this paper is to discuss the methodology, testing challenges, and results of testing that a team of experts from Areva NP, Alden Research Laboratory, Inc (ALDEN), and Performance Contracting Inc. (PCI) has developed. The team is currently implementing a comprehensive solution to the issue of Emergency Core Cooling System (ECCS) sump strainer blockage facing Pressurized Water Reactor (PWR) Nuclear Plants. The team has successfully demonstrated two key results from the testing of passive Sure-FlowTM strainers, which were designed to distribute the required flow over a large surface area resulting in extremely low approach velocities. First, the actualmore » head loss (pressure drop) as tested, across the prototype strainers, was much lower than the calculated head loss using the Nuclear Regulatory Commission (NRC) approved NUREG/CR-6224 head loss correlation. Second, the penetration fractions were much lower than those seen in the NRC sponsored debris penetration tests. (author)« less

Visualization of tumor blockage and rerouting of lymphatic drainage in penile cancer patients by use of SPECT/CT.

PubMed

Leijte, Joost A P; van der Ploeg, Iris M C; Valdés Olmos, Renato A; Nieweg, Omgo E; Horenblas, Simon

2009-03-01

The reliability of sentinel node biopsy is dependent on the accurate visualization and identification of the sentinel node(s). It has been suggested that extensive metastatic involvement of a sentinel node can lead to blocked inflow and rerouting of lymph fluid to a "neo-sentinel node" that may not yet contain tumor cells, causing a false-negative result. However, there is little evidence to support this hypothesis. Recently introduced hybrid SPECT/CT scanners provide both tomographic lymphoscintigraphy and anatomic detail. Such a scanner enabled the present study of the concept of tumor blockage and rerouting of lymphatic drainage in patients with palpable groin metastases. Seventeen patients with unilateral palpable and cytologically proven metastases in the groin underwent bilateral conventional lymphoscintigraphy and SPECT/CT before sentinel node biopsy of the contralateral groin. The pattern of lymphatic drainage in the 17 palpable groin metastases was evaluated for signs of tumor blockage or rerouting. On the CT images, the palpable node metastases could be identified in all 17 groins. Four of the 17 palpable node metastases (24%) showed uptake of radioactivity on the SPECT/CT images. In 10 groins, rerouting of lymphatic drainage to a neo-sentinel node was seen; one neo-sentinel node was located in the contralateral groin. A complete absence of lymphatic drainage was seen in the remaining 3 groins. The concept of tumor blockage and rerouting was visualized in 76% of the groins with palpable metastases. Precise physical examination and preoperative ultrasound with fine-needle aspiration cytology may identify nodes with considerable tumor invasion at an earlier stage and thereby reduce the incidence of false-negative results.

Contrasting Transcriptional Programs Control Postharvest Development of Apples (Malus x domestica Borkh.) Submitted to Cold Storage and Ethylene Blockage.

PubMed

Storch, Tatiane Timm; Finatto, Taciane; Bruneau, Maryline; Orsel-Baldwin, Mathilde; Renou, Jean-Pierre; Rombaldi, Cesar Valmor; Quecini, Vera; Laurens, François; Girardi, César Luis

2017-09-06

Apple is commercially important worldwide. Favorable genomic contexts and postharvest technologies allow year-round availability. Although ripening is considered a unidirectional developmental process toward senescence, storage at low temperatures, alone or in combination with ethylene blockage, is effective in preserving apple properties. Quality traits and genome wide expression were integrated to investigate the mechanisms underlying postharvest changes. Development and conservation techniques were responsible for transcriptional reprogramming and distinct programs associated with quality traits. A large portion of the differentially regulated genes constitutes a program involved in ripening and senescence, whereas a smaller module consists of genes associated with reestablishment and maintenance of juvenile traits after harvest. Ethylene inhibition was associated with a reversal of ripening by transcriptional induction of anabolic pathways. Our results demonstrate that the blockage of ethylene perception and signaling leads to upregulation of genes in anabolic pathways. We also associated complex phenotypes to subsets of differentially regulated genes.

A New Network Modeling Tool for the Ground-based Nuclear Explosion Monitoring Community

NASA Astrophysics Data System (ADS)

Merchant, B. J.; Chael, E. P.; Young, C. J.

2013-12-01

Network simulations have long been used to assess the performance of monitoring networks to detect events for such purposes as planning station deployments and network resilience to outages. The standard tool has been the SAIC-developed NetSim package. With correct parameters, NetSim can produce useful simulations; however, the package has several shortcomings: an older language (FORTRAN), an emphasis on seismic monitoring with limited support for other technologies, limited documentation, and a limited parameter set. Thus, we are developing NetMOD (Network Monitoring for Optimal Detection), a Java-based tool designed to assess the performance of ground-based networks. NetMOD's advantages include: coded in a modern language that is multi-platform, utilizes modern computing performance (e.g. multi-core processors), incorporates monitoring technologies other than seismic, and includes a well-validated default parameter set for the IMS stations. NetMOD is designed to be extendable through a plugin infrastructure, so new phenomenological models can be added. Development of the Seismic Detection Plugin is being pursued first. Seismic location and infrasound and hydroacoustic detection plugins will follow. By making NetMOD an open-release package, it can hopefully provide a common tool that the monitoring community can use to produce assessments of monitoring networks and to verify assessments made by others.

Hydroacoustic mapping to define sedimentation rates and characterize lentic habitats in DeSoto Lake, DeSoto National Wildlife Refuge

USGS Publications Warehouse

Elliott, Caroline M.; Jacobson, Robert B.; Chojnacki, Kimberly A.

2006-01-01

Hydroacoustic tools were used to map depth, elevation, and substrate on DeSoto Lake in March 2006. DeSoto Lake, located on the DeSoto National Wildlife Refuge in Iowa and Nebraska, is one of the largest oxbow lakes of the Missouri River system. It is used by over 500,000 migratory birds each fall and spring and is also an important aquatic resource for anglers. Management concerns at the lake include the effects of erosion and sedimentation, aquatic vegetation establishment, shorebird habitat availability at different lake levels, and fish habitat structure. DeSoto Lake was cut off from the Missouri River in 1960, and the current mapping updates previous lower-resolution bathymetric maps created from lake surveys in 1967 and 1979. The new maps provide managers tools to assess aquatic habitats and provide a baseline for future monitoring of lake sedimentation and erosion.

Blockage of progestin physiology disrupts ovarian differentiation in XX Nile tilapia (Oreochromis niloticus)

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

Zhou, Linyan; Luo, Feng; Fang, Xuelian

Previous studies indicated that maturation inducing hormone, 17α, 20β-Dihydroxy-4-pregnen-3-one (DHP), probably through nuclear progestin receptor (Pgr), might be involved in spermatogenesis and oogenesis in fish. To further elucidate DHP actions in teleostean ovarian differentiation, we analyzed the expression of pgr in the ovary of Nile tilapia (Oreochromis niloticus), and performed RU486 (a synthetic Pgr antagonist) treatment in XX fish from 5 days after hatching (dah) to 120dah. Tilapia Pgr was abundantly expressed in the follicular cells surrounding oocytes at 30 and 90dah. Continuous RU486 treatment led to the blockage of oogenesis and masculinization of somatic cells in XX fish. Terminationmore » of RU486 treatment and maintenance in normal condition resulted in testicular differentiation, and estrogen compensation in RU486-treated XX fish successfully restored oogenesis. In RU486-treated XX fish, transcript levels of female dominant genes were significantly reduced, while male-biased genes were evidently augmented. Meanwhile, both germ cell mitotic and meiotic markers were substantially reduced. Consistently, estrogen production levels were significantly declined in RU486-treated XX fish. Taken together, our data further proved that DHP, possibly through Pgr, might be essential in the ovarian differentiation and estrogen production in fish. - Highlights: • DHP plays a critical role in early stage oogenesis of XX tilapia. • Blockage of DHP actions by RU486 treatment led to masculinization and/or sex reversal in XX tilapia. • Both DHP and estrogen are indispensable for ovarian differentiation.« less

Infant Approach and Withdrawal in Response to a Goal Blockage: Its Antecedent Causes and Its Effect on Toddler Persistence

PubMed Central

Lewis, Michael; Sullivan, Margaret W.; Kim, Hillary Mi-Sung

2015-01-01

In two separate longitudinal studies, infants and their mothers were seen in three longitudinal visits. At two months, they were observed in free play where mothers’ contingency toward their infants was obtained. At five months, a goal blockage response was produced when a previously learned contingent response became ineffective in producing an interesting event. Infants’ emotional responses, in particular anger and sad facial expressions, were observed. At two years, toddlers’ persistence at play was assessed by measuring children’s responses to an interruption of their play. In both studies, the amount of toddlers’ persistence was positively related to their anger response to the blocked goal at five months. Maternal contingency was not related either to infants’ response to the blocked goal nor to their persistence at play. These findings provide evidence for the contribution to and the consequences of infants’ response to a goal blockage and the role of anger as an approach emotion. PMID:26389608

Results from a 14-month hydroacoustic monitoring of the three mid-oceanic ridges in the Indian Ocean

NASA Astrophysics Data System (ADS)

Royer, J.-Y.; Dziak, R. P.; Delatre, M.; Chateau, R.; Brachet, C.; Haxel, J. H.; Matsumoto, H.; Goslin, J.; Brandon, V.; Bohnenstielh, D. R.

2009-04-01

From October 2006 to January 2008, an hydroacoustic experiment in the Indian Ocean was carried out by the CNRS/University of Brest and NOAA/Oregon State University to monitor the low-level seismic activity associated with the three contrasting spreading ridges and deforming zones in the Indian Ocean. Three autonomous hydrophones were moored in the SOFAR channel by R/V Marion Dufresne for 14 months in the Madagascar Basin, and northeast and southwest of Amsterdam Island, complementing the two permanent hydroacoustic stations of the Comprehensive nuclear-Test-Ban Treaty Organization (CTBTO) located near Diego Garcia Island and off Cape Leeuwin. The three instruments successfully collected 14 month of continuous acoustic records. Combined with the records from the permanent stations, the array detected 1780 acoustic events consisting mostly of earthquake generated T-waves, but also of iceberg tremors from Wilkes Land, Antarctica. Within the triangle defined by the temporary array, the three ridges exhibit contrasting seismicity patterns. Along the Southeast Indian ridge (SEIR), the 272 acoustic events (vs 24 events in the NEIC catalog) occur predominantly along the transform faults ; only one ridge segment (76˚E) displays a continuous activity for 10 months. Along the Central Indian Ridge (CIR), seismicity is distributed along fracture zones and ridge segments (269 events vs 45 NEIC events), with two clusters of events near the triple junction (24-25S) and south of Marie-Celeste FZ (18.5S). Along the Southwest Indian Ridge (SWIR), the 222 events (vs 31 NEIC events) are distributed along the ridge segments with a larger number of events west of Melville FZ and a cluster at 58E. The immediate vicinity of the Rodrigues triple junction shows periods of quiescence and of intense activity. Some large earthquakes (Mb>5) near the triple junction (SEIR and CIR) seem to be preceded by several acoustic events that may be precursors. Finally, off-ridge seismicity is mostly

Computing under-ice discharge: A proof-of-concept using hydroacoustics and the Probability Concept

NASA Astrophysics Data System (ADS)

Fulton, John W.; Henneberg, Mark F.; Mills, Taylor J.; Kohn, Michael S.; Epstein, Brian; Hittle, Elizabeth A.; Damschen, William C.; Laveau, Christopher D.; Lambrecht, Jason M.; Farmer, William H.

2018-07-01

Under-ice discharge is estimated using open-water reference hydrographs; however, the ratings for ice-affected sites are generally qualified as poor. The U.S. Geological Survey (USGS), in collaboration with the Colorado Water Conservation Board, conducted a proof-of-concept to develop an alternative method for computing under-ice discharge using hydroacoustics and the Probability Concept. The study site was located south of Minturn, Colorado (CO), USA, and was selected because of (1) its proximity to the existing USGS streamgage 09064600 Eagle River near Minturn, CO, and (2) its ease-of-access to verify discharge using a variety of conventional methods. From late September 2014 to early March 2015, hydraulic conditions varied from open water to under ice. These temporal changes led to variations in water depth and velocity. Hydroacoustics (tethered and uplooking acoustic Doppler current profilers and acoustic Doppler velocimeters) were deployed to measure the vertical-velocity profile at a singularly important vertical of the channel-cross section. Because the velocity profile was non-standard and cannot be characterized using a Power Law or Log Law, velocity data were analyzed using the Probability Concept, which is a probabilistic formulation of the velocity distribution. The Probability Concept-derived discharge was compared to conventional methods including stage-discharge and index-velocity ratings and concurrent field measurements; each is complicated by the dynamics of ice formation, pressure influences on stage measurements, and variations in cross-sectional area due to ice formation. No particular discharge method was assigned as truth. Rather one statistical metric (Kolmogorov-Smirnov; KS), agreement plots, and concurrent measurements provided a measure of comparability between various methods. Regardless of the method employed, comparisons between each method revealed encouraging results depending on the flow conditions and the absence or presence of ice

Computing under-ice discharge: A proof-of-concept using hydroacoustics and the Probability Concept

USGS Publications Warehouse

Fulton, John W.; Henneberg, Mark F.; Mills, Taylor J.; Kohn, Michael S.; Epstein, Brian; Hittle, Elizabeth A.; Damschen, William C.; Laveau, Christopher D.; Lambrecht, Jason M.; Farmer, William H.

2018-01-01

Under-ice discharge is estimated using open-water reference hydrographs; however, the ratings for ice-affected sites are generally qualified as poor. The U.S. Geological Survey (USGS), in collaboration with the Colorado Water Conservation Board, conducted a proof-of-concept to develop an alternative method for computing under-ice discharge using hydroacoustics and the Probability Concept.The study site was located south of Minturn, Colorado (CO), USA, and was selected because of (1) its proximity to the existing USGS streamgage 09064600 Eagle River near Minturn, CO, and (2) its ease-of-access to verify discharge using a variety of conventional methods. From late September 2014 to early March 2015, hydraulic conditions varied from open water to under ice. These temporal changes led to variations in water depth and velocity. Hydroacoustics (tethered and uplooking acoustic Doppler current profilers and acoustic Doppler velocimeters) were deployed to measure the vertical-velocity profile at a singularly important vertical of the channel-cross section. Because the velocity profile was non-standard and cannot be characterized using a Power Law or Log Law, velocity data were analyzed using the Probability Concept, which is a probabilistic formulation of the velocity distribution. The Probability Concept-derived discharge was compared to conventional methods including stage-discharge and index-velocity ratings and concurrent field measurements; each is complicated by the dynamics of ice formation, pressure influences on stage measurements, and variations in cross-sectional area due to ice formation.No particular discharge method was assigned as truth. Rather one statistical metric (Kolmogorov-Smirnov; KS), agreement plots, and concurrent measurements provided a measure of comparability between various methods. Regardless of the method employed, comparisons between each method revealed encouraging results depending on the flow conditions and the absence or presence of ice

Infant Approach and Withdrawal in Response to a Goal Blockage: Its Antecedent Causes and Its Effect on Toddler Persistence

ERIC Educational Resources Information Center

Lewis, Michael; Sullivan, Margaret W.; Kim, Hillary Mi-Sung

2015-01-01

In 2 separate longitudinal studies, infants and their mothers were seen in 3 longitudinal visits. At 2 months, they were observed in free play where mothers' contingency toward their infants was obtained. At 5 months, a goal blockage response was produced when a previously learned contingent response became ineffective in producing an interesting…

Spatiotemporal distribution of the seismicity along the Mid-Atlantic Ridge north of the Azores from hydroacoustic data: Insights into seismogenic processes in a ridge-hot spot context

NASA Astrophysics Data System (ADS)

Goslin, J.; Perrot, J.; Royer, J.-Y.; Martin, C.; LourençO, N.; Luis, J.; Dziak, R. P.; Matsumoto, H.; Haxel, J.; Fowler, M. J.; Fox, C. G.; Lau, A. T.-K.; Bazin, S.

2012-02-01

The seismicity of the North Atlantic was monitored from May 2002 to September 2003 by the `SIRENA array' of autonomous hydrophones. The hydroacoustic signals provide a unique data set documenting numerous low-magnitude earthquakes along the section of the Mid-Atlantic Ridge (MAR) located in a ridge-hot spot interaction context. During the experiment, 1696 events were detected along the MAR axis between 40°N and 51°N, with a magnitude of completeness level ofmb≈ 2.4. Inside the array, location errors are in the order of 2 km, and errors in the origin time are less than 1 s. From this catalog, 15 clusters were detected. The distribution of source level (SL) versus time within each cluster is used to discriminate clusters occurring in a tectonic context from those attributed to non-tectonic (i.e. volcanic or hydrothermal) processes. The location of tectonic and non-tectonic sequences correlates well with regions with positive and negative Mantle Bouguer Anomalies (MBAs), indicating the presence of thinner/colder and thicker/warmer crust respectively. At the scale of the entire array, both the complete and declustered catalogs derived from the hydroacoustic signals show an increase of the seismicity rate from the Azores up to 43°30'N suggesting a diminishing influence of the Azores hot spot on the ridge-axis temperature, and well correlated with a similar increase in the along-axis MBAs. The comparison of the MAR seismicity with the Residual MBA (RMBA) at different scales leads us to think that the low-magnitude seismicity rates are directly related to along-axis variations in lithosphere rheology and temperatures.

Gap junction blockage promotes cadmium-induced apoptosis in BRL 3A derived from Buffalo rat liver cells.

PubMed

Hu, Di; Zou, Hui; Han, Tao; Xie, Junze; Dai, Nannan; Zhuo, Liling; Gu, Jianhong; Bian, Jianchun; Yuan, Yan; Liu, Xuezhong; Liu, Zongping

2016-03-01

Gap junctions mediate direct communication between cells; however, toxicological cascade triggered by nonessential metals can abrogate cellular signaling mediated by gap junctions. Although cadmium (Cd) is known to induce apoptosis in organs and tissues, the mechanisms that underlie gap junction activity in Cd-induced apoptosis in BRL 3A rat liver cells has yet to be established. In this study, we showed that Cd treatment decreased the cell index (a measure of cellular electrical impedance) in BRL 3A cells. Mechanistically, we found that Cd exposure decreased expression of connexin 43 (Cx43), increased expression of p-Cx43 and elevated intracellular free Ca(2+) concentration, corresponding to a decrease in gap junctional intercellular communication. Gap junction blockage pretreatment with 18β-glycyrrhizic acid (GA) promoted Cd-induced apoptosis, involving changes in expression of Bax, Bcl-2, caspase-3 and the mitochondrial transmembrane electrical potential (Δψm). Additionally, GA was found to enhance ERK and p38 activation during Cd-induced activation of mitogen-activated protein kinases, but had no significant effect on JNK activation. Our results indicated the apoptosis-related proteins and the ERK and p38 signaling pathways may participate in gap junction blockage promoting Cd-induced apoptosis in BRL 3A cells.

PNA binding to the non-template DNA strand interferes with transcription, suggesting a blockage mechanism mediated by R-loop formation.

PubMed

Belotserkovskii, Boris P; Hanawalt, Philip C

2015-11-01

Peptide Nucleic Acids (PNAs) are artificial DNA mimics with superior nucleic acid binding capabilities. T7 RNA polymerase (T7 RNAP) transcription upon encountering PNA bound to the non-template DNA strand was studied in vitro. A characteristic pattern of blockage signals was observed, extending downstream from the PNA binding site, similar to that produced by G-rich homopurine-homopyrimidine (hPu-hPy) sequences and likely caused by R-loop formation. Since blocked transcription complexes in association with stable R-loops may interfere with replication and in some cases trigger apoptosis, targeted R-loop formation might be employed to inactivate selected cells, such as those in tumors, based upon their unique complement of expressed genes. © 2014 The Authors. Molecular Carcinogenesis published by Wiley Periodicals, Inc.

Effect of extradural blockage upon glucose and urea kinetics in surgical patients

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

Shaw, J.H.; Galler, L.; Holdaway, I.M.

1987-09-01

We have determined the metabolic effects induced by the use of extradural blockage with 0.5 per cent bupivacaine hydrochloride in a group of surgical patients. Turnover rates of glucose and urea were determined isotopically using radioisotopes and studies were performed both in the basal state and during total parenteral nutrition. In the basal state, extradural blockade resulted in a decrease in the turnover rates of both glucose and urea. In addition, when extradural blockade was instituted while the patients were receiving total parenteral nutrition, there was also a significant fall in glucose turnover. We conclude that the use of extraduralmore » blockade is effective as a means of conserving bodily resources in surgical patients both in the basal state and during total parenteral nutrition.« less

Knockdown of miR-128a induces Lin28a expression and reverts myeloid differentiation blockage in acute myeloid leukemia

PubMed Central

De Luca, Luciana; Trino, Stefania; Laurenzana, Ilaria; Tagliaferri, Daniela; Falco, Geppino; Grieco, Vitina; Bianchino, Gabriella; Nozza, Filomena; Campia, Valentina; D'Alessio, Francesca; La Rocca, Francesco; Caivano, Antonella; Villani, Oreste; Cilloni, Daniela; Musto, Pellegrino; Del Vecchio, Luigi

2017-01-01

Lin28A is a highly conserved RNA-binding protein that concurs to control the balance between stemness and differentiation in several tissue lineages. Here, we report the role of miR-128a/Lin28A axis in blocking cell differentiation in acute myeloid leukemia (AML), a genetically heterogeneous disease characterized by abnormally controlled proliferation of myeloid progenitor cells accompanied by partial or total inability to undergo terminal differentiation. First, we found Lin28A underexpressed in blast cells from AML patients and AML cell lines as compared with CD34+ normal precursors. In vitro transfection of Lin28A in NPM1-mutated OCI-AML3 cell line significantly triggered cell-cycle arrest and myeloid differentiation, with increased expression of macrophage associate genes (EGR2, ZFP36 and ANXA1). Furthermore, miR-128a, a negative regulator of Lin28A, was found overexpressed in AML cells compared with normal precursors, especially in acute promyelocytic leukemia (APL) and in ‘AML with maturation’ (according to 2016 WHO classification of myeloid neoplasms and acute leukemia). Its forced overexpression by lentiviral infection in OCI-AML3 downregulated Lin28A with ensuing repression of macrophage-oriented differentiation. Finally, knockdown of miR-128a in OCI-AML3 and in APL/AML leukemic cells (by transfection and lentiviral infection, respectively) induced myeloid cell differentiation and increased expression of Lin28A, EGR2, ZFP36 and ANXA1, reverting myeloid differentiation blockage. In conclusion, our findings revealed a new mechanism for AML differentiation blockage, suggesting new strategies for AML therapy based upon miR-128a inhibition. PMID:28569789

Evolution of submarine eruptive activity during the 2011-2012 El Hierro event as documented by hydroacoustic images and remotely operated vehicle observations

NASA Astrophysics Data System (ADS)

Somoza, L.; González, F. J.; Barker, S. J.; Madureira, P.; Medialdea, T.; de Ignacio, C.; Lourenço, N.; León, R.; Vázquez, J. T.; Palomino, D.

2017-08-01

Submarine volcanic eruptions are frequent and important events, yet they are rarely observed. Here we relate bathymetric and hydroacoustic images from the 2011 to 2012 El Hierro eruption with surface observations and deposits imaged and sampled by ROV. As a result of the shallow submarine eruption, a new volcano named Tagoro grew from 375 to 89 m depth. The eruption consisted of two main phases of edifice construction intercalated with collapse events. Hydroacoustic images show that the eruptions ranged from explosive to effusive with variable plume types and resulting deposits, even over short time intervals. At the base of the edifice, ROV observations show large accumulations of lava balloons changing in size and type downslope, coinciding with the area where floating lava balloon fallout was observed. Peaks in eruption intensity during explosive phases generated vigorous bubbling at the surface, extensive ash, vesicular lapilli and formed high-density currents, which together with periods of edifice gravitational collapse, produced extensive deep volcaniclastic aprons. Secondary cones developed in the last stages and show evidence for effusive activity with lava ponds and lava flows that cover deposits of stacked lava balloons. Chaotic masses of heterometric boulders around the summit of the principal cone are related to progressive sealing of the vent with decreasing or variable magma supply. Hornitos represent the final eruptive activity with hydrothermal alteration and bacterial mats at the summit. Our study documents the distinct evolution of a submarine volcano and highlights the range of deposit types that may form and be rapidly destroyed in such eruptions.