Antisymmetrized molecular dynamics of wave packets with stochastic incorporation of Vlasov equation

International Nuclear Information System (INIS)

Ono, Akira; Horiuchi, Hisashi.

1996-01-01

The first purpose of this report is to present an extended AMD model which can generally describe such minor branching processes by removing the restriction on the one-body distribution function. This is done not by generalizing the wave packets to arbitrary single-particle wave functions but by representing the diffused and/or deformed wave packet as an ensemble of Gaussian wave packets. In other words, stochastic displacements are given to the wave packets in phase space so that the ensemble-average of the time evolution of the one-body distribution function is essentially equivalent to the solution of Vlasov equation which does not have any restriction on the shape of wave packets. This new model is called AMD-V. Although AMD-V is equivalent to Vlasov equation in the instantaneous time evolution of the one-body distribution function for an AMD wave function, AMD-V describes the branching into channels and the fluctuation of the mean field which are caused by the spreading or the splitting of the single-particle wave function. The second purpose of this report is to show the drastic effect of this new stochastic process of wave packet splitting on the dynamics of heavy ion collisions, especially in the fragmentation mechanism. We take the 40 Ca + 40 Ca system at the incident energy 35 MeV/nucleon. It will be shown that the reproduction of data by the AMD-V calculation is surprisingly good. We will see that the effect of the wave packet diffusion is crucially important to remove the spurious binary feature of the AMD calculation and to enable the multi-fragment final state. (J.P.N.)

Magnetohydrodynamic waves, electrohydrodynamic waves and photons

International Nuclear Information System (INIS)

Carstoin, J.

1984-01-01

Two new subjects have lately attracted increased attention: the magnetohydrodynamics (m.h.d.) and the theory of lasers. Equally important is the subject of electrohydrodynamics (e.h.d.). Now, clearly, all electromagnetic waves carry photons; it is the merit of Louis de Broglie to have had reconciled the validity of the Maxwell equations with existence of the latter. I have, recently, derived L. de Broglie's equations from the equations C. It seems natural to assume that the m.h.d. waves carry also photons, but how to reconcile the m.h.d axioms with the existence of photons ... a problem which has, so far, escaped the notice of physicists. In the lines which follows, an attempt is made to incorporate the photons in the m.h.d. waves, re e.h.d. waves in a rather simple fashion

Numerical modelling of nearshore wave transformation

Digital Repository Service at National Institute of Oceanography (India)

Chandramohan, P.; Nayak, B.U.; SanilKumar, V.

A software has been developed for numerical refraction study based on finite amplitude wave theories. Wave attenuation due to shoaling, bottom friction, bottom percolation and viscous dissipation has also been incorporated. The software...

Earthquake early warning using P-waves that appear after initial S-waves

Science.gov (United States)

Kodera, Y.

2017-12-01

As measures for underprediction for large earthquakes with finite faults and overprediction for multiple simultaneous earthquakes, Hoshiba (2013), Hoshiba and Aoki (2015), and Kodera et al. (2016) proposed earthquake early warning (EEW) methods that directly predict ground motion by computing the wave propagation of observed ground motion. These methods are expected to predict ground motion with a high accuracy even for complicated scenarios because these methods do not need source parameter estimation. On the other hand, there is room for improvement in their rapidity because they predict strong motion prediction mainly based on the observation of S-waves and do not explicitly use P-wave information available before the S-waves. In this research, we propose a real-time P-wave detector to incorporate P-wave information into these wavefield-estimation approaches. P-waves within a few seconds from the P-onsets are commonly used in many existing EEW methods. In addition, we focus on P-waves that may appear in the later part of seismic waves. Kurahashi and Irikura (2013) mentioned that P-waves radiated from strong motion generation areas (SMGAs) were recognizable after S-waves of the initial rupture point in the 2011 off the Pacific coast of Tohoku earthquake (Mw 9.0) (the Tohoku-oki earthquake). Detecting these P-waves would enhance the rapidity of prediction for the peak ground motion generated by SMGAs. We constructed a real-time P-wave detector that uses a polarity analysis. Using acceleration records in boreholes of KiK-net (band-pass filtered around 0.5-10 Hz with site amplification correction), the P-wave detector performed the principal component analysis with a sliding window of 4 s and calculated P-filter values (e.g. Ross and Ben-Zion, 2014). The application to the Tohoku-oki earthquake (Mw 9.0) showed that (1) peaks of P-filter that corresponded to SMGAs appeared in several stations located near SMGAs and (2) real-time seismic intensities (Kunugi et al

Generalized theory of resonance scattering (GTRS) using the translational addition theorem for spherical wave functions.

Science.gov (United States)

Mitri, Farid

2014-11-01

The generalized theory of resonance scattering (GTRS) by an elastic spherical target in acoustics is extended to describe the arbitrary scattering of a finite beam using the addition theorem for the spherical wave functions of the first kind under a translation of the coordinate origin. The advantage of the proposed method over the standard discrete spherical harmonics transform previously used in the GTRS formalism is the computation of the off-axial beam-shape coefficients (BSCs) stemming from a closed-form partial-wave series expansion representing the axial BSCs in spherical coordinates. With this general method, the arbitrary acoustical scattering can be evaluated for any particle shape and size, whether the particle is partially or completely illuminated by the incident beam. Numerical examples for the axial and off-axial resonance scattering from an elastic sphere placed arbitrarily in the field of a finite circular piston transducer with uniform vibration are provided. Moreover, the 3-D resonance directivity patterns illustrate the theory and reveal some properties of the scattering. Numerous applications involving the scattering phenomenon in imaging, particle manipulation, and the characterization of multiphase flows can benefit from the present analysis because all physically realizable beams radiate acoustical waves from finite transducers as opposed to waves of infinite extent.

Climate Change Effects on Heat Waves and Future Heat Wave-Associated IHD Mortality in Germany

Directory of Open Access Journals (Sweden)

Stefan Zacharias

2014-12-01

Full Text Available The influence of future climate change on the occurrence of heat waves and its implications for heat wave-related mortality due to ischemic heart diseases (IHD in Germany is studied. Simulations of 19 regional climate models with a spatial resolution of 0.25° × 0.25° forced by the moderate climate change scenario A1B are analyzed. Three model time periods of 30 years are evaluated, representing present climate (1971–2000, near future climate (2021–2050, and remote future climate (2069–2098. Heat waves are defined as periods of at least three consecutive days with daily mean air temperature above the 97.5th percentile of the all-season temperature distribution. Based on the model simulations, future heat waves in Germany will be significantly more frequent, longer lasting and more intense. By the end of the 21st century, the number of heat waves will be tripled compared to present climate. Additionally, the average duration of heat waves will increase by 25%, accompanied by an increase of the average temperature during heat waves by about 1 K. Regional analyses show that stronger than average climate change effects are observed particularly in the southern regions of Germany. Furthermore, we investigated climate change impacts on IHD mortality in Germany applying temperature projections from 19 regional climate models to heat wave mortality relationships identified in a previous study. Future IHD excess deaths were calculated both in the absence and presence of some acclimatization (i.e., that people are able to physiologically acclimatize to enhanced temperature levels in the future time periods by 0% and 50%, respectively. In addition to changes in heat wave frequency, we incorporated also changes in heat wave intensity and duration into the future mortality evaluations. The results indicate that by the end of the 21st century the annual number of IHD excess deaths in Germany attributable to heat waves is expected to rise by factor 2

Substitution or addition? How overweight and obese adults incorporate vegetables into their diet during a randomized controlled vegetable feeding trial

Science.gov (United States)

Objective: When attempting to eat healthier, individuals may add vegetables to their diet (addition) without changing other eating behaviors. Alternatively, individuals adding vegetables may decrease consumption of other foods (substitution). Distinguishing between the two means of incorporation of ...

Incorporation of quantum statistical features in molecular dynamics

International Nuclear Information System (INIS)

Ohnishi, Akira; Randrup, J.

1995-01-01

We formulate a method for incorporating quantum fluctuations into molecular-dynamics simulations of many-body systems, such as those employed for energetic nuclear collision processes. Based on Fermi's Golden Rule, we allow spontaneous transitions to occur between the wave packets which are not energy eigenstates. The ensuing diffusive evolution in the space of the wave packet parameters exhibits appealing physical properties, including relaxation towards quantum-statistical equilibrium. (author)

Dissipation of Wave Energy by Cohesive Sediments

National Research Council Canada - National Science Library

Kaihatu, James M; Sheremet, Alexandru

2004-01-01

Wave energy dissipation by bottom muds is studied. A dissipation mechanism which contains explicit expressions of wavenumber modification due to a viscous bottom fluid is incorporated into a nonlinear wave shoaling model...

Ion temperature effects on magnetotail Alfvén wave propagation and electron energization: ION TEMPERATURE EFFECTS ON ALFVÉN WAVES

Energy Technology Data Exchange (ETDEWEB)

Damiano, P. A. [Princeton Center for Heliophysics, Princeton Plasma Physics Laboratory, Princeton University, Princeton New Jersey USA; Johnson, J. R. [Princeton Center for Heliophysics, Princeton Plasma Physics Laboratory, Princeton University, Princeton New Jersey USA; Chaston, C. C. [Space Sciences Laboratory, University of California, Berkeley California USA; School of Physics, University of Sydney, Sydney New South Wales Australia

2015-07-01

A new 2-D self-consistent hybrid gyrofluid-kinetic electron model in dipolar coordinates is presented and used to simulate dispersive-scale Alfvén wave pulse propagation from the equator to the ionosphere along an L = 10 magnetic field line. The model is an extension of the hybrid MHD-kinetic electron model that incorporates ion Larmor radius corrections via the kinetic fluid model of Cheng and Johnson (1999). It is found that consideration of a realistic ion to electron temperature ratio decreases the propagation time of the wave from the plasma sheet to the ionosphere by several seconds relative to a ρi=0 case (which also implies shorter timing for a substorm onset signal) and leads to significant dispersion of wave energy perpendicular to the ambient magnetic field. Additionally, ion temperature effects reduce the parallel current and electron energization all along the field line for the same magnitude perpendicular electric field perturbation.

Incorporating Floating Surface Objects into a Fully Dispersive Surface Wave Model

Science.gov (United States)

2016-04-19

Bateman c , Joseph Calantoni c , James T. Kirby b a NRL Code 7320, 1009 Balch Blvd, Stennis Space Center, MS 39529 USA b Center for Applied Coastal...wave prop- agation. J. Waterway Port Coast. Ocean Eng. 119, 618–638 . rzech, M., Shi, F., Calantoni, J., Bateman , S., Veeramony, J., 2014. Small-scale...F., Bateman , S., Calantoni, J., 2016. Modeling small- scale physics of waves and ice in the MIZ. AGU 2016 Ocean Sciences Meeting, Session 9483

Full-wave modeling of ICRF waves: global and quasi-local descriptions

International Nuclear Information System (INIS)

Dumont, R. J.

2007-01-01

Waves in the Ion Cyclotron Range of Frequencies (ICRF) undergo significant space dispersion as they propagate in magnetic fusion plasmas, making it necessary to incorporate non-local effects in their physical description. Full-wave codes are routinely employed to simulate ICRF heating experiments in tokamaks. The vast majority of these codes rely on a description of the plasma based on a 'quasi-local' derivation of the dielectric tensor, i.e. assuming that the range of space dispersion remains small compared to the system dimensions. However, non-local effects caused by wide particle orbits are expected to play a significant role in current and future experiments featuring wave-driven fast ions, fusion-born alpha particles... Global formalisms have thus been proposed to include these effects in a more comprehensive fashion. Based on a description of the particle dynamics in terms of action-angle variables, a full-wave code, named EVE, is currently under development. Its first version, presented here, incorporates quasi-local expressions valid to second order in Larmor radius, derived from the more general Hamiltonian formalism. The obtained tool has the advantage of being compatible with the current requirements of integrated modeling, and lends itself to direct comparisons with existing codes

A numerical study of the wave shoaling effect on wind-wave momentum flux

Science.gov (United States)

Hao, Xuanting; Shen, Lian

2017-11-01

Momentum transfer between wind and waves is crucial to many physical processes in air-sea interactions. For decades, there has been a number of observational evidence that the surface roughness in the nearshore region is notably higher than in the open sea. In order to explain the mechanism behind this important phenomenon, in particular the wave shoaling effect on surface roughness, we conduct a series of numerical experiments using the wind-wave module of WOW (Wave-Ocean-Wind), a high-fidelity computational framework developed in house. We use prescribed monochromatic waves with linear shoaling effect incorporated, while the wind field is simulated using wall-resolved large-eddy simulation. A comparison between a shallow water wave case and deep water wave cases shows remarkably stronger wave effects on the wind for the former. Detailed analyses show that the increased surface roughness is closely associated with the increased form drag that is mainly due to the reduced wave age in wave shoaling.

Wave propagation in embedded inhomogeneous nanoscale plates incorporating thermal effects

Science.gov (United States)

Ebrahimi, Farzad; Barati, Mohammad Reza; Dabbagh, Ali

2018-04-01

In this article, an analytical approach is developed to study the effects of thermal loading on the wave propagation characteristics of an embedded functionally graded (FG) nanoplate based on refined four-variable plate theory. The heat conduction equation is solved to derive the nonlinear temperature distribution across the thickness. Temperature-dependent material properties of nanoplate are graded using Mori-Tanaka model. The nonlocal elasticity theory of Eringen is introduced to consider small-scale effects. The governing equations are derived by the means of Hamilton's principle. Obtained frequencies are validated with those of previously published works. Effects of different parameters such as temperature distribution, foundation parameters, nonlocal parameter, and gradient index on the wave propagation response of size-dependent FG nanoplates have been investigated.

Wave energy converter effects on wave propagation: A sensitivity study in Monterey Bay, CA

Science.gov (United States)

Chang, G.; Jones, C. A.; Roberts, J.; Magalen, J.; Ruehl, K.; Chartrand, C.

2014-12-01

The development of renewable offshore energy in the United States is growing rapidly and wave energy is one of the largest resources currently being evaluated. The deployment of wave energy converter (WEC) arrays required to harness this resource could feasibly number in the hundreds of individual devices. The WEC arrays have the potential to alter nearshore wave propagation and circulation patterns and ecosystem processes. As the industry progresses from pilot- to commercial-scale it is important to understand and quantify the effects of WECs on the natural nearshore processes that support a local, healthy ecosystem. To help accelerate the realization of commercial-scale wave power, predictive modeling tools have been developed and utilized to evaluate the likelihood of environmental impact. At present, direct measurements of the effects of different types of WEC arrays on nearshore wave propagation are not available; therefore wave model simulations provide the groundwork for investigations of the sensitivity of model results to prescribed WEC characteristics over a range of anticipated wave conditions. The present study incorporates a modified version of an industry standard wave modeling tool, SWAN (Simulating WAves Nearshore), to simulate wave propagation through a hypothetical WEC array deployment site on the California coast. The modified SWAN, referred to as SNL-SWAN, incorporates device-specific WEC power take-off characteristics to more accurately evaluate a WEC device's effects on wave propagation. The primary objectives were to investigate the effects of a range of WEC devices and device and array characteristics (e.g., device spacing, number of WECs in an array) on nearshore wave propagation using SNL-SWAN model simulations. Results showed that significant wave height was most sensitive to variations in WEC device type and size and the number of WEC devices in an array. Locations in the lee centerline of the arrays in each modeled scenario showed the

A new version of DWPI (inelastic pion-nucleus scattering) to incorporate microscopic form factors and differing proton and neutron radii

International Nuclear Information System (INIS)

Funsten, H.O.

1979-01-01

This is a modification of the Eisenstein-Miller program for calculation of collective inelastic pion-nucleus differential cross sections using free π-N scattering amplitudes. This revision permits the additional use of microscopic (shell model) proton and neutron form factors. It also incorporates separate proton and neutron radii for the nuclear density rho(r) generating the distorted wave optical potential. (Auth.)

An Analysis of an Implicit Factored Scheme for Simulating Shock Waves

Science.gov (United States)

1988-05-01

can cope with a wide range of boundary conditions and equations of state, For modelling -( shock waves in solids, elastic- plastic terms must also be...positive caracteristic speeds. One-sided schemes have superior dissipative and dispersive properties compared to those of centered schemes (Steger and...Elastic- plastic con. ditions must be- incorporated into the problem and usually the addition of suitable bource or sink terms to c-’ustion (1

Dye-Incorporated Polynaphthalenediimide Acceptor for Additive-Free High-Performance All-Polymer Solar Cells.

Science.gov (United States)

Chen, Dong; Yao, Jia; Chen, Lie; Yin, Jingping; Lv, Ruizhi; Huang, Bin; Liu, Siqi; Zhang, Zhi-Guo; Yang, Chunhe; Chen, Yiwang; Li, Yongfang

2018-04-16

All-polymer solar cells (all-PSCs) can offer unique advantages for applications in flexible devices, and naphthalene diimide (NDI)-based polymer acceptors are the widely used polymer acceptors. However, their power conversion efficiency (PCE) still lags behind that of state-of-the-art polymer solar cells, due to low light absorption, suboptimal energy levels and the strong aggregation of the NDI-based polymer acceptor. Herein, a rhodanine-based dye molecule was introduced into the NDI-based polymer acceptor by simple random copolymerization and showed an improved light absorption coefficient, an up-shifted lowest unoccupied molecular orbital level and reduced crystallization. Consequently, additive-free all-PSCs demonstrated a high PCE of 8.13 %, which is one of the highest performance characteristics reported for all-PSCs to date. These results indicate that incorporating a dye into the n-type polymer gives insight into the precise design of high-performance polymer acceptors for all-PSCs. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Coherent Wave Measurement Buoy Arrays to Support Wave Energy Extraction

Science.gov (United States)

Spada, F.; Chang, G.; Jones, C.; Janssen, T. T.; Barney, P.; Roberts, J.

2016-02-01

Wave energy is the most abundant form of hydrokinetic energy in the United States and wave energy converters (WECs) are being developed to extract the maximum possible power from the prevailing wave climate. However, maximum wave energy capture is currently limited by the narrow banded frequency response of WECs as well as extended protective shutdown requirements during periods of large waves. These limitations must be overcome in order to maximize energy extraction, thus significantly decreasing the cost of wave energy and making it a viable energy source. Techno-economic studies of several WEC devices have shown significant potential to improve wave energy capture efficiency through operational control strategies that incorporate real-time information about local surface wave motions. Integral Consulting Inc., with ARPA-E support, is partnering with Sandia National Laboratories and Spoondrift LLC to develop a coherent array of wave-measuring devices to relay and enable the prediction of wave-resolved surface dynamics at a WEC location ahead of real time. This capability will provide necessary information to optimize power production of WECs through control strategies, thereby allowing for a single WEC design to perform more effectively across a wide range of wave environments. The information, data, or work presented herein was funded in part by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0000514.

Turbulence closure: turbulence, waves and the wave-turbulence transition – Part 1: Vanishing mean shear

Directory of Open Access Journals (Sweden)

H. Z. Baumert

2009-03-01

Full Text Available This paper extends a turbulence closure-like model for stably stratified flows into a new dynamic domain in which turbulence is generated by internal gravity waves rather than mean shear. The model turbulent kinetic energy (TKE, K balance, its first equation, incorporates a term for the energy transfer from internal waves to turbulence. This energy source is in addition to the traditional shear production. The second variable of the new two-equation model is the turbulent enstrophy (Ω. Compared to the traditional shear-only case, the Ω-equation is modified to account for the effect of the waves on the turbulence time and space scales. This modification is based on the assumption of a non-zero constant flux Richardson number in the limit of vanishing mean shear when turbulence is produced exclusively by internal waves. This paper is part 1 of a continuing theoretical development. It accounts for mean shear- and internal wave-driven mixing only in the two limits of mean shear and no waves and waves but no mean shear, respectively.

The new model reproduces the wave-turbulence transition analyzed by D'Asaro and Lien (2000b. At small energy density E of the internal wave field, the turbulent dissipation rate (ε scales like ε~E². This is what is observed in the deep sea. With increasing E, after the wave-turbulence transition has been passed, the scaling changes to ε~E¹. This is observed, for example, in the highly energetic tidal flow near a sill in Knight Inlet. The new model further exhibits a turbulent length scale proportional to the Ozmidov scale, as observed in the ocean, and predicts the ratio between the turbulent Thorpe and Ozmidov length scales well within the range observed in the ocean.

Biological effects of laser-induced stress waves

International Nuclear Information System (INIS)

Doukas, A.; Lee, S.; McAuliffe, D.

1995-01-01

Laser-induced stress waves can be generated by one of the following mechanisms: Optical breakdown, ablation or rapid heating of an absorbing medium. These three modes of laser interaction with matter allow the investigation of cellular and tissue responses to stress waves with different characteristics and under different conditions. The most widely studied phenomena are those of the collateral damage seen in photodisruption in the eye and in 193 run ablation of cornea and skin. On the other hand, the therapeutic application of laser-induced stress waves has been limited to the disruption of noncellular material such as renal stones, atheromatous plaque and vitreous strands. The effects of stress waves to cells and tissues can be quite disparate. Stress waves can fracture tissue, damage cells, and increase the permeability of the plasma membrane. The viability of cell cultures exposed to stress waves increases with the peak stress and the number of pulses applied. The rise time of the stress wave also influences the degree of cell injury. In fact, cell viability, as measured by thymidine incorporation, correlates better with the stress gradient than peak stress. Recent studies have also established that stress waves induce a transient increase of the permeability of the plasma membrane in vitro. In addition, if the stress gradient is below the damage threshhold, the cells remain viable. Thus, stress waves can be useful as a means of drug delivery, increasing the intracellular drug concentration and allowing the use of drugs which are impermeable to the cell membrane. The present studies show that it is important to create controllable stress waves. The wavelength tunability and the micropulse structure of the free electron laser is ideal for generating stress waves with independently adjustable parameters, such as rise time, duration and peak stress

How to turn gravity waves into Alfven waves and other such tricks

International Nuclear Information System (INIS)

Newington, Marie E; Cally, Paul S

2011-01-01

Recent observations of travelling gravity waves at the base of the chromosphere suggest an interplay between gravity wave propagation and magnetic field. Our aims are: to explain the observation that gravity wave flux is suppressed in magnetic regions; to understand why we see travelling waves instead of standing waves; and to see if gravity waves can undergo mode conversion and couple to Alfven waves in regions where the plasma beta is of order unity. We model gravity waves in a VAL C atmosphere, subject to a uniform magnetic field of various orientations, considering both adiabatic and radiatively damped propagation. Results indicate that in the presence of a magnetic field, the gravity wave can propagate as a travelling wave, with the magnetic field orientation playing a crucial role in determining the wave character. For the majority of magnetic field orientations, the gravity wave is reflected at low heights as a slow magneto-acoustic wave, explaining the observation of reduced flux in magnetic regions. In a highly inclined magnetic field, the gravity wave undergoes mode conversion to either field guided acoustic waves or Alfven waves. The primary effect of incorporating radiative damping is a reduction in acoustic and magnetic fluxes measured at the top of the integration region. By demonstrating the mode conversion of gravity waves to Alfven waves, this work identifies a possible pathway for energy transport from the solar surface to the upper atmosphere.

Evaluation of an Approximate Method for Incorporating Floating Docks in Harbor Wave Prediction Models

Science.gov (United States)

2005-11-25

fact, Koutandos et al. (2004) even now have had to limit their work only to the x–z plane while using a similar approach. In this paper, therefore, we...breakwater Koutandos et al. (2004) have presented data pertaining to transmission coefficients for waves passing a fixed, infinitely long, floating...4. Values of A and B for determining α. Fig. 5. Wave height comparison with data presented in Koutandos et al. (2004). Fig. 6. Wave transmission past

Challenges in Defining Tsunami Wave Height

Science.gov (United States)

Stroker, K. J.; Dunbar, P. K.; Mungov, G.; Sweeney, A.; Arcos, N. P.

2017-12-01

The NOAA National Centers for Environmental Information (NCEI) and co-located World Data Service for Geophysics maintain the global tsunami archive consisting of the historical tsunami database, imagery, and raw and processed water level data. The historical tsunami database incorporates, where available, maximum wave heights for each coastal tide gauge and deep-ocean buoy that recorded a tsunami signal. These data are important because they are used for tsunami hazard assessment, model calibration, validation, and forecast and warning. There have been ongoing discussions in the tsunami community about the correct way to measure and report these wave heights. It is important to understand how these measurements might vary depending on how the data were processed and the definition of maximum wave height. On September 16, 2015, an 8.3 Mw earthquake located 48 km west of Illapel, Chile generated a tsunami that was observed all over the Pacific region. We processed the time-series water level data for 57 tide gauges that recorded this tsunami and compared the maximum wave heights determined from different definitions. We also compared the maximum wave heights from the NCEI-processed data with the heights reported by the NOAA Tsunami Warning Centers. We found that in the near field different methods of determining the maximum tsunami wave heights could result in large differences due to possible instrumental clipping. We also found that the maximum peak is usually larger than the maximum amplitude (½ peak-to-trough), but the differences for the majority of the stations were Warning Centers. Since there is currently only one field in the NCEI historical tsunami database to store the maximum tsunami wave height, NCEI will consider adding an additional field for the maximum peak measurement.

Model for small arms fire muzzle blast wave propagation in air

Science.gov (United States)

Aguilar, Juan R.; Desai, Sachi V.

2011-11-01

Accurate modeling of small firearms muzzle blast wave propagation in the far field is critical to predict sound pressure levels, impulse durations and rise times, as functions of propagation distance. Such a task being relevant to a number of military applications including the determination of human response to blast noise, gunfire detection and localization, and gun suppressor design. Herein, a time domain model to predict small arms fire muzzle blast wave propagation is introduced. The model implements a Friedlander wave with finite rise time which diverges spherically from the gun muzzle. Additionally, the effects in blast wave form of thermoviscous and molecular relaxational processes, which are associated with atmospheric absorption of sound were also incorporated in the model. Atmospheric absorption of blast waves is implemented using a time domain recursive formula obtained from numerical integration of corresponding differential equations using a Crank-Nicholson finite difference scheme. Theoretical predictions from our model were compared to previously recorded real world data of muzzle blast wave signatures obtained by shooting a set different sniper weapons of varying calibers. Recordings containing gunfire acoustical signatures were taken at distances between 100 and 600 meters from the gun muzzle. Results shows that predicted blast wave slope and exponential decay agrees well with measured data. Analysis also reveals the persistency of an oscillatory phenomenon after blast overpressure in the recorded wave forms.

Incorporating fault zone head wave and direct wave secondary arrival times into seismic tomography: Application at Parkfield, California

Science.gov (United States)

Bennington, Ninfa L.; Thurber, Clifford; Peng, Zhigang; Zhang, Haijiang; Zhao, Peng

2013-03-01

We present a three-dimensional (3D) P wave velocity (Vp) model of the Parkfield region that utilizes existing P wave arrival time data, including fault zone head waves (FZHWs), and data from direct wave secondary arrivals (DWSAs). The first-arrival and DWSA travel times are obtained as the global- and local-minimum travel time paths, respectively. The inclusion of FZHWs and DWSAs results in as much as a 5% and a 10% increase in the across-fault velocity contrast, respectively, for the Vp model at Parkfield relative to that of Thurber et al. [2006]. Viewed along strike, three pronounced velocity contrast regions are observed: a pair of strong positive velocity contrasts (SW fast), one NW of the 1966 Parkfield earthquake hypocenter and the other SE of the 2004 Parkfield earthquake hypocenter, and a strong negative velocity contrast (NE fast) between the two hypocenters. The negative velocity contrast partially to entirely encompasses peak coseismic slip estimated in several slip models for the 2004 earthquake, suggesting that the negative velocity contrast played a part in defining the rupture patch of the 2004 Parkfield earthquake. Following Ampuero and Ben-Zion (2008), the pattern of velocity contrasts is consistent with the observed bilateral rupture propagation for the 2004 Parkfield earthquake. Although the velocity contrasts also suggest bilateral rupture propagation for the 1966 Parkfield earthquake, the fault is creeping to the NW here, i.e., exhibiting velocity-strengthening behavior. Thus, it is not surprising that rupture propagated only SE during this event.

Enhancing Wave Energy Competitiveness through Co-Located Wind and Wave Energy Farms. A Review on the Shadow Effect

OpenAIRE

Sharay Astariz; Gregorio Iglesias

2015-01-01

Wave energy is one of the most promising alternatives to fossil fuels due to the enormous available resource; however, its development may be slowed as it is often regarded as uneconomical. The largest cost reductions are expected to be obtained through economies of scale and technological progress. In this sense, the incorporation of wave energy systems into offshore wind energy farms is an opportunity to foster the development of wave energy. The synergies between both renewables can be rea...

The high resolution shear wave seismic reflection technique

International Nuclear Information System (INIS)

Johnson, W.J.; Clark, J.C.

1991-04-01

This report presents the state-of-the-art of the high resolution S-wave reflection technique. Published and unpublished literature has been reviewed and discussions have been held with experts. Result is to confirm that the proposed theoretical and practical basis for identifying aquifer systems using both P- and S-wave reflections is sound. Knowledge of S-wave velocity and P-wave velocity is a powerful tool for assessing the fluid characteristics of subsurface layers. Material properties and lateral changes in material properties such as change from clay to sand, can be inferred from careful dual evaluation of P and S-wave records. The high resolution S-wave reflection technique has seen its greatest application to date as part of geotechnical studies for building foundations in the Far East. Information from this type of study has been evaluated and will be incorporated in field studies. In particular, useful information regarding S-wave sources, noise suppression and recording procedures will be incorporated within the field studies. Case histories indicate that the best type of site for demonstrating the power of the high resolution S-wave technique will be in unconsolidated soil without excessive structural complexities. More complex sites can form the basis for subsequent research after the basic principles of the technique can be established under relatively uncomplicated conditions

Real Time Wave Forecasting Using Wind Time History and Genetic Programming

Directory of Open Access Journals (Sweden)

A.R. Kambekar

2014-12-01

Full Text Available The significant wave height and average wave period form an essential input for operational activities in ocean and coastal areas. Such information is important in issuing appropriate warnings to people planning any construction or instillation works in the oceanic environment. Many countries over the world routinely collect wave and wind data through a network of wave rider buoys. The data collecting agencies transmit the resulting information online to their registered users through an internet or a web-based system. Operational wave forecasts in addition to the measured data are also made and supplied online to the users. This paper discusses operational wave forecasting in real time mode at locations where wind rather than wave data are continuously recorded. It is based on the time series modeling and incorporates an artificial intelligence technique of genetic programming. The significant wave height and average wave period values are forecasted over a period of 96 hr in future from the observations of wind speed and directions extending to a similar time scale in the past. Wind measurements made by floating buoys at eight different locations around India over a period varying from 1.5 yr to 9.0 yr were considered. The platform of Matlab and C++ was used to develop a graphical user interface that will extend an internet based user-friendly access of the forecasts to any registered user of the data dissemination authority.

A multimodal wave spectrum-based approach for statistical downscaling of local wave climate

Science.gov (United States)

Hegermiller, Christie; Antolinez, Jose A A; Rueda, Ana C.; Camus, Paula; Perez, Jorge; Erikson, Li; Barnard, Patrick; Mendez, Fernando J.

2017-01-01

Characterization of wave climate by bulk wave parameters is insufficient for many coastal studies, including those focused on assessing coastal hazards and long-term wave climate influences on coastal evolution. This issue is particularly relevant for studies using statistical downscaling of atmospheric fields to local wave conditions, which are often multimodal in large ocean basins (e.g. the Pacific). Swell may be generated in vastly different wave generation regions, yielding complex wave spectra that are inadequately represented by a single set of bulk wave parameters. Furthermore, the relationship between atmospheric systems and local wave conditions is complicated by variations in arrival time of wave groups from different parts of the basin. Here, we address these two challenges by improving upon the spatiotemporal definition of the atmospheric predictor used in statistical downscaling of local wave climate. The improved methodology separates the local wave spectrum into “wave families,” defined by spectral peaks and discrete generation regions, and relates atmospheric conditions in distant regions of the ocean basin to local wave conditions by incorporating travel times computed from effective energy flux across the ocean basin. When applied to locations with multimodal wave spectra, including Southern California and Trujillo, Peru, the new methodology improves the ability of the statistical model to project significant wave height, peak period, and direction for each wave family, retaining more information from the full wave spectrum. This work is the base of statistical downscaling by weather types, which has recently been applied to coastal flooding and morphodynamic applications.

Comparison of advanced gravitational-wave detectors

International Nuclear Information System (INIS)

Harry, Gregory M.; Houser, Janet L.; Strain, Kenneth A.

2002-01-01

We compare two advanced designs for gravitational-wave antennas in terms of their ability to detect two possible gravitational wave sources. Spherical, resonant mass antennas and interferometers incorporating resonant sideband extraction (RSE) were modeled using experimentally measurable parameters. The signal-to-noise ratio of each detector for a binary neutron star system and a rapidly rotating stellar core were calculated. For a range of plausible parameters we found that the advanced LIGO interferometer incorporating RSE gave higher signal-to-noise ratios than a spherical detector resonant at the same frequency for both sources. Spheres were found to be sensitive to these sources at distances beyond our galaxy. Interferometers were sensitive to these sources at far enough distances that several events per year would be expected

On the use of wave parameterizations and a storm impact scaling model in National Weather Service Coastal Flood and decision support operations

Science.gov (United States)

Mignone, Anthony; Stockdon, H.; Willis, M.; Cannon, J.W.; Thompson, R.

2012-01-01

National Weather Service (NWS) Weather Forecast Offices (WFO) are responsible for issuing coastal flood watches, warnings, advisories, and local statements to alert decision makers and the general public when rising water levels may lead to coastal impacts such as inundation, erosion, and wave battery. Both extratropical and tropical cyclones can generate the prerequisite rise in water level to set the stage for a coastal impact event. Forecasters use a variety of tools including computer model guidance and local studies to help predict the potential severity of coastal flooding. However, a key missing component has been the incorporation of the effects of waves in the prediction of total water level and the associated coastal impacts. Several recent studies have demonstrated the importance of incorporating wave action into the NWS coastal flood program. To follow up on these studies, this paper looks at the potential of applying recently developed empirical parameterizations of wave setup, swash, and runup to the NWS forecast process. Additionally, the wave parameterizations are incorporated into a storm impact scaling model that compares extreme water levels to beach elevation data to determine the mode of coastal change at predetermined “hotspots” of interest. Specifically, the storm impact model compares the approximate storm-induced still water level, which includes contributions from tides, storm surge, and wave setup, to dune crest elevation to determine inundation potential. The model also compares the combined effects of tides, storm surge, and the 2 % exceedance level for vertical wave runup (including both wave setup and swash) to dune toe and crest elevations to determine if erosion and/or ocean overwash may occur. The wave parameterizations and storm impact model are applied to two cases in 2009 that led to significant coastal impacts and unique forecast challenges in North Carolina: the extratropical “Nor'Ida” event during 11-14 November and

Characterization of active paper packaging incorporated with ginger pulp oleoresin

Science.gov (United States)

Wiastuti, T.; Khasanah, L. U.; Atmaka Kawiji, W.; Manuhara, G. J.; Utami, R.

2016-02-01

Utilization of ginger pulp waste from herbal medicine and instant drinks industry in Indonesia currently used for fertilizer and fuel, whereas the ginger pulp still contains high oleoresin. Active paper packaging were developed incorporated with ginger pulp oleoresin (0%, 2%, 4%, and 6% w/w). Physical (thickness, tensile strength, and folding endurance, moisture content), sensory characteristics and antimicrobial activity of the active paper were evaluated. Selected active paper then were chemically characterized (functional groups). The additional of ginger pulp oleoresin levels are reduced tensile strength, folding endurance and sensory characteristic (color, texture and overall) and increased antimicrobial activity. Due to physical, sensory characteristic and antimicrobial activity, active paper with 2% ginger pulp oleoresin incorporation was selected. Characteristics of selected paper were 9.93% of water content; 0.81 mm of thickness; 0.54 N / mm of tensile strength; 0.30 of folding endurance; 8.43 mm inhibits the growth of Pseudomonas fluorescence and 27.86 mm inhibits the growth of Aspergillus niger (antimicrobial activity) and neutral preference response for sensory properties. For chemical characteristic, selected paper had OH functional group of ginger in 3422.83 cm-1 of wave number and indicated contain red ginger active compounds.

Stochastic resonance in a stochastic bistable system with additive noises and square–wave signal

International Nuclear Information System (INIS)

Feng, Guo; Xiang-Dong, Luo; Shao-Fu, Li; Yu-Rong, Zhou

2010-01-01

This paper considers the stochastic resonance in a stochastic bistable system driven by a periodic square-wave signal and a static force as well as by additive white noise and dichotomous noise from the viewpoint of signal-to-noise ratio. It finds that the signal-to-noise ratio appears as stochastic resonance behaviour when it is plotted as a function of the noise strength of the white noise and dichotomous noise, as a function of the system parameters, or as a function of the static force. Moreover, the influence of the strength of the stochastic potential force and the correlation rate of the dichotomous noise on the signal-to-noise ratio is investigated. (general)

Advances in real-time millimeter-wave imaging radiometers for avionic synthetic vision

Science.gov (United States)

Lovberg, John A.; Chou, Ri-Chee; Martin, Christopher A.; Galliano, Joseph A., Jr.

1995-06-01

Millimeter-wave imaging has advantages over conventional visible or infrared imaging for many applications because millimeter-wave signals can travel through fog, snow, dust, and clouds with much less attenuation than infrared or visible light waves. Additionally, passive imaging systems avoid many problems associated with active radar imaging systems, such as radar clutter, glint, and multi-path return. ThermoTrex Corporation previously reported on its development of a passive imaging radiometer that uses an array of frequency-scanned antennas coupled to a multichannel acousto-optic spectrum analyzer (Bragg-cell) to form visible images of a scene through the acquisition of thermal blackbody radiation in the millimeter-wave spectrum. The output from the Bragg cell is imaged by a standard video camera and passed to a computer for normalization and display at real-time frame rates. An application of this system is its incorporation as part of an enhanced vision system to provide pilots with a synthetic view of a runway in fog and during other adverse weather conditions. Ongoing improvements to a 94 GHz imaging system and examples of recent images taken with this system will be presented. Additionally, the development of dielectric antennas and an electro- optic-based processor for improved system performance, and the development of an `ultra- compact' 220 GHz imaging system will be discussed.

Acoustics waves and oscillations

CERN Document Server

Sen, S.N.

2013-01-01

Parameters of acoustics presented in a logical and lucid style Physical principles discussed with mathematical formulations Importance of ultrasonic waves highlighted Dispersion of ultrasonic waves in viscous liquids explained This book presents the theory of waves and oscillations and various applications of acoustics in a logical and simple form. The physical principles have been explained with necessary mathematical formulation and supported by experimental layout wherever possible. Incorporating the classical view point all aspects of acoustic waves and oscillations have been discussed together with detailed elaboration of modern technological applications of sound. A separate chapter on ultrasonics emphasizes the importance of this branch of science in fundamental and applied research. In this edition a new chapter ''Hypersonic Velocity in Viscous Liquids as revealed from Brillouin Spectra'' has been added. The book is expected to present to its readers a comprehensive presentation of the subject matter...

Wave-induced current considering wave-tide interaction in Haeundae

Science.gov (United States)

Lim, Hak Soo

2017-04-01

The Haeundae, located at the south eastern end of the Korean Peninsula, is a famous beach, which has an approximately 1.6 km long and 70 m wide coastline. The beach has been repeatedly eroded by the swell waves caused by typhoons in summer and high waves originating in the East Sea in winter. The Korean government conducted beach restoration projects including beach nourishment (620,000 m3) and construction of two submerged breakwaters near both ends of the beach. To prevent the beach erosion and to support the beach restoration project, the Korean government initiated a R&D project, the development of coastal erosion control technology since 2013. As a part of the project, we have been measuring waves and currents at a water depth of 22 m, 1.8 km away from the beach using an acoustic wave and current meter (AWAC) continuously for more than three years; we have also measured waves and currents intensively near the surf-zone in summer and winter. In this study, a numerical simulation using a wave and current coupled model (ROMS-SWAN) was conducted for determining the wave-induced current considering seasonal swell waves (Hs : 2.5 m, Tp: 12 s) and for better understanding of the coastal process near the surf-zone in Haeundae. By comparing the measured and simulated results, we found that cross-shore current during summer is mainly caused by the eddy produced by the wave-induced current near the beach, which in turn, is generated by the strong waves coming from the SSW and S directions. During other seasons, longshore wave-induced current is produced by the swell waves coming from the E and ESE directions. The longshore current heading west toward Dong-Back Island, west end of the beach, during all the seasons and eddy current toward Mipo-Port, east end of the beach, in summer which is well matched with the observed residual current. The wave-induced current with long-term measurement data is incorporated in simulation of sediment transport modeling for developing

Effects of a Heat Wave on Nocturnal Stomatal Conductance in Eucalyptus camaldulensis

Directory of Open Access Journals (Sweden)

Víctor Resco de Dios

2018-06-01

Full Text Available Nocturnal transpiration constitutes a significant yet poorly understood component of the global water cycle. Modeling nocturnal transpiration has been complicated by recent findings showing that stomata respond differently to environmental drivers over day- vs. night-time periods. Here, we propose that nocturnal stomatal conductance depends on antecedent daytime conditions. We tested this hypothesis across six genotypes of Eucalyptus camaldulensis Dehnh. growing under different CO2 concentrations (ambient vs. elevated and exposed to contrasting temperatures (ambient vs. heat wave for four days prior to the night of measurements, when all plants experienced ambient temperature conditions. We observed significant effects after the heat wave that led to 36% reductions in nocturnal stomatal conductance. The response was partly driven by changes in daytime stomatal behavior but additional factors may have come into play. We also observed significant differences in response to the heat wave across genotypes, likely driven by local adaptation to their climate of origin, but CO2 played no effect. Stomatal models may need to incorporate the role of antecedent effects to improve projections particularly after drastic changes in the environment such as heat waves.

P- and S-wave velocity models incorporating the Cascadia subduction zone for 3D earthquake ground motion simulations—Update for Open-File Report 2007–1348

Science.gov (United States)

Stephenson, William J.; Reitman, Nadine G.; Angster, Stephen J.

2017-12-20

In support of earthquake hazards studies and ground motion simulations in the Pacific Northwest, threedimensional (3D) P- and S-wave velocity (VP and VS , respectively) models incorporating the Cascadia subduction zone were previously developed for the region encompassed from about 40.2°N. to 50°N. latitude, and from about 122°W. to 129°W. longitude (fig. 1). This report describes updates to the Cascadia velocity property volumes of model version 1.3 ([V1.3]; Stephenson, 2007), herein called model version 1.6 (V1.6). As in model V1.3, the updated V1.6 model volume includes depths from 0 kilometers (km) (mean sea level) to 60 km, and it is intended to be a reference for researchers who have used, or are planning to use, this model in their earth science investigations. To this end, it is intended that the VP and VS property volumes of model V1.6 will be considered a template for a community velocity model of the Cascadia region as additional results become available. With the recent and ongoing development of the National Crustal Model (NCM; Boyd and Shah, 2016), we envision any future versions of this model will be directly integrated with that effort

Wind-wave modelling aspects within complicate topography

Directory of Open Access Journals (Sweden)

S. Christopoulos

Full Text Available Wave forecasting aspects for basins with complicate geomorphology, such as the Aegean Sea, are investigated through an intercomparison study. The efficiency of the available wind models (ECMWF, UKMO to reproduce wind patterns over special basins, as well as three wave models incorporating different physics and characteristics (WAM, AUT, WACCAS, are tested for selected storm cases representing the typical wind situations over the basin. From the wave results, discussed in terms of time-series and statistical parameters, the crucial role is pointed out of the wind resolution and the reliability of the different wave models to estimate the wave climate in such a basin. The necessary grid resolution is also tested, while for a specific test case (December 1991 ERS-1 satellite data are compared with those of the model.

Spin effect on parametric interactions of waves in magnetoplasmas

International Nuclear Information System (INIS)

Shahid, M.; Melrose, D. B.; Jamil, M.; Murtaza, G.

2012-01-01

The parametric decay instability of upper hybrid wave into low-frequency electromagnetic Shear Alfvén wave and Ordinary mode radiation (O-mode) has been investigated in an electron-ion plasma immersed in the uniform external magnetic field. Incorporating quantum effect due to electron spin, the fluid model has been used to investigate the linear and nonlinear response of the plasma species for three-wave coupling in a magnetoplasma. It is shown that the spin of electrons has considerable effect on the parametric decay of upper hybrid wave into Ordinary mode radiation (O-mode) and Shear Alfvén wave even in classical regime.

Computer simulation of driven Alfven waves

International Nuclear Information System (INIS)

Geary, J.L. Jr.

1986-01-01

The first particle simulation study of shear Alfven wave resonance heating is presented. Particle simulation codes self-consistently follow the time evolution of the individual and collective aspects of particle dynamics as well as wave dynamics in a fully nonlinear fashion. Alfven wave heating is a possible means of increasing the temperature of magnetized plasmas. A new particle simulation model was developed for this application that incorporates Darwin's formulation of the electromagnetic fields with a guiding center approximation for electron motion perpendicular to the ambient magnetic field. The implementation of this model and the examination of its theoretical and computational properties are presented. With this model, several cases of Alfven wave heating is examined in both uniform and nonuniform simulation systems in a two dimensional slab. For the inhomogeneous case studies, the kinetic Alfven wave develops in the vicinity of the shear Alfven resonance region

Reconnections of Wave Vortex Lines

Science.gov (United States)

Berry, M. V.; Dennis, M. R.

2012-01-01

When wave vortices, that is nodal lines of a complex scalar wavefunction in space, approach transversely, their typical crossing and reconnection is a two-stage process incorporating two well-understood elementary events in which locally coplanar hyperbolas switch branches. The explicit description of this reconnection is a pedagogically useful…

Dust acoustic shock wave at high dust density

International Nuclear Information System (INIS)

Ghosh, Samiran; Sarkar, Susmita; Khan, Manoranjan; Avinash, K.; Gupta, M. R.

2003-01-01

Dust acoustic (DA) shock wave at high dust density, i.e., the dust electroacoustic (DEA) or dust Coulomb (DC) shock wave has been investigated incorporating the nonadiabatic dust charge variation. The nonlinear DEA (DC) shock wave is seen to be governed by the Korteweg-de Vries Burger equation, in which the Burger term is proportional to the nonadiabaticity generated dissipation. It is seen that the shock strength decreases but after reaching minimum, it increases as the dust space charge density |q d n d | increases and the shock strength of DA wave is greater than that of DEA (DC) wave. Moreover the DEA (DC) shock width increases appreciably with increase mass m i of the ion component of the dusty plasma but for DA shock wave the effect is weak

Assimilation of radar altimeter data in numerical wave models: an impact study in two different wave climate regions

Directory of Open Access Journals (Sweden)

G. Emmanouil

2007-03-01

Full Text Available An operational assimilation system incorporating significant wave height observations in high resolution numerical wave models is studied and evaluated. In particular, altimeter satellite data provided by the European Space Agency (ESA-ENVISAT are assimilated in the wave model WAM which operates in two different wave climate areas: the Mediterranean Sea and the Indian Ocean. The first is a wind-sea dominated area while in the second, swell is the principal part of the sea state, a fact that seriously affects the performance of the assimilation scheme. A detailed study of the different impact is presented and the resulting forecasts are evaluated against available buoy and satellite observations. The corresponding results show a considerable improvement in wave forecasting for the Indian Ocean while in the Mediterranean Sea the assimilation impact is restricted to isolated areas.

Self-Consistent Model of Magnetospheric Electric Field, Ring Current, Plasmasphere, and Electromagnetic Ion Cyclotron Waves: Initial Results

Science.gov (United States)

Gamayunov, K. V.; Khazanov, G. V.; Liemohn, M. W.; Fok, M.-C.; Ridley, A. J.

2009-01-01

Further development of our self-consistent model of interacting ring current (RC) ions and electromagnetic ion cyclotron (EMIC) waves is presented. This model incorporates large scale magnetosphere-ionosphere coupling and treats self-consistently not only EMIC waves and RC ions, but also the magnetospheric electric field, RC, and plasmasphere. Initial simulations indicate that the region beyond geostationary orbit should be included in the simulation of the magnetosphere-ionosphere coupling. Additionally, a self-consistent description, based on first principles, of the ionospheric conductance is required. These initial simulations further show that in order to model the EMIC wave distribution and wave spectral properties accurately, the plasmasphere should also be simulated self-consistently, since its fine structure requires as much care as that of the RC. Finally, an effect of the finite time needed to reestablish a new potential pattern throughout the ionosphere and to communicate between the ionosphere and the equatorial magnetosphere cannot be ignored.

CIMI simulations with newly developed multiparameter chorus and plasmaspheric hiss wave models

Science.gov (United States)

Aryan, Homayon; Sibeck, David G.; Kang, Suk-Bin; Balikhin, Michael A.; Fok, Mei-Ching; Agapitov, Oleksiy; Komar, Colin M.; Kanekal, Shrikanth G.; Nagai, Tsugunobu

2017-09-01

Numerical simulation studies of the Earth's radiation belts are important to understand the acceleration and loss of energetic electrons. The Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model considers the effects of the ring current and plasmasphere on the radiation belts to obtain plausible results. The CIMI model incorporates pitch angle, energy, and cross diffusion of electrons, due to chorus and plasmaspheric hiss waves. These parameters are calculated using statistical wave distribution models of chorus and plasmaspheric hiss amplitudes. However, currently, these wave distribution models are based only on a single-parameter, geomagnetic index (AE) and could potentially underestimate the wave amplitudes. Here we incorporate recently developed multiparameter chorus and plasmaspheric hiss wave models based on geomagnetic index and solar wind parameters. We then perform CIMI simulations for two geomagnetic storms and compare the flux enhancement of MeV electrons with data from the Van Allen Probes and Akebono satellites. We show that the relativistic electron fluxes calculated with multiparameter wave models resemble the observations more accurately than the relativistic electron fluxes calculated with single-parameter wave models. This indicates that wave models based on a combination of geomagnetic index and solar wind parameters are more effective as inputs to radiation belt models.

Accounting for adaptation and intensity in projecting heat wave-related mortality.

Science.gov (United States)

Wang, Yan; Nordio, Francesco; Nairn, John; Zanobetti, Antonella; Schwartz, Joel D

2018-02-01

How adaptation and intensity of heat waves affect heat wave-related mortality is unclear, making health projections difficult. We estimated the effect of heat waves, the effect of the intensity of heat waves, and adaptation on mortality in 209 U.S. cities with 168 million people during 1962-2006. We improved the standard time-series models by incorporating the intensity of heat waves using excess heat factor (EHF) and estimating adaptation empirically using interactions with yearly mean summer temperature (MST). We combined the epidemiological estimates for heat wave, intensity, and adaptation with the Coupled Model Intercomparison Project Phase 5 (CMIP5) multi-model dataset to project heat wave-related mortality by 2050. The effect of heat waves increased with its intensity. Adaptation to heat waves occurred, which was shown by the decreasing effect of heat waves with MST. However, adaptation was lessened as MST increased. Ignoring adaptation in projections would result in a substantial overestimate of the projected heat wave-related mortality (by 277-747% in 2050). Incorporating the empirically estimated adaptation into projections would result in little change in the projected heat wave-related mortality between 2006 and 2050. This differs regionally, however, with increasing mortality over time for cities in the southern and western U.S. but decreasing mortality over time for the north. Accounting for adaptation is important to reduce bias in the projections of heat wave-related mortality. The finding that the southern and western U.S. are the areas that face increasing heat-related deaths is novel, and indicates that more regional adaptation strategies are needed. Copyright © 2017 Elsevier Inc. All rights reserved.

Analytical Time-Domain Solution of Plane Wave Propagation Across a Viscoelastic Rock Joint

Science.gov (United States)

Zou, Yang; Li, Jianchun; Laloui, Lyesse; Zhao, Jian

2017-10-01

The effects of viscoelastic filled rock joints on wave propagation are of great significance in rock engineering. The solutions in time domain for plane longitudinal ( P-) and transverse ( S-) waves propagation across a viscoelastic rock joint are derived based on Maxwell and Kelvin models which are, respectively, applied to describe the viscoelastic deformational behaviour of the rock joint and incorporated into the displacement discontinuity model (DDM). The proposed solutions are verified by comparing with the previous studies on harmonic waves, which are simulated by sinusoidal incident P- and S-waves. Comparison between the predicted transmitted waves and the experimental data for P-wave propagation across a joint filled with clay is conducted. The Maxwell is found to be more appropriate to describe the filled joint. The parametric studies show that wave propagation is affected by many factors, such as the stiffness and the viscosity of joints, the incident angle and the duration of incident waves. Furthermore, the dependences of the transmission and reflection coefficients on the specific joint stiffness and viscosity are different for the joints with Maxwell and Kelvin behaviours. The alternation of the reflected and transmitted waveforms is discussed, and the application scope of this study is demonstrated by an illustration of the effects of the joint thickness. The solutions are also extended for multiple parallel joints with the virtual wave source method and the time-domain recursive method. For an incident wave with arbitrary waveform, it is convenient to adopt the present approach to directly calculate wave propagation across a viscoelastic rock joint without additional mathematical methods such as the Fourier and inverse Fourier transforms.

Spiral wave drift and complex-oscillatory spiral waves caused by heterogeneities in two-dimensional in vitro cardiac tissues

International Nuclear Information System (INIS)

Woo, Sung-Jae; Hong, Jin Hee; Kim, Tae Yun; Bae, Byung Wook; Lee, Kyoung J

2008-01-01

Understanding spiral reentry wave dynamics in cardiac systems is important since it underlies various cardiac arrhythmia including cardiac fibrillation. Primary cultures of dissociated cardiac cells have been a convenient and useful system for studying cardiac wave dynamics, since one can carry out systematic and quantitative studies with them under well-controlled environments. One key drawback of the dissociated cell culture is that, inevitably, some spatial inhomogeneities in terms of cell types and density, and/or the degree of gap junction connectivity, are introduced to the system during the preparation. These unintentional spatial inhomogeneities can cause some non-trivial wave dynamics, for example, the entrainment dynamics among different spiral waves and the generation of complex-oscillatory spiral waves. The aim of this paper is to quantify these general phenomena in an in vitro cardiac system and provide explanations for them with a simple physiological model having some realistic spatial inhomogeneities incorporated

Interfacial wave theory for dendritic structure of a growing needle crystal. I - Local instability mechanism. II - Wave-emission mechanism at the turning point

Science.gov (United States)

Xu, Jian-Jun

1989-01-01

The complicated dendritic structure of a growing needle crystal is studied on the basis of global interfacial wave theory. The local dispersion relation for normal modes is derived in a paraboloidal coordinate system using the multiple-variable-expansion method. It is shown that the global solution in a dendrite growth process incorporates the morphological instability factor and the traveling wave factor.

Hanstholm phase 2B. Offshore wave energy test 1994 - 1996

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-11-01

The wave power converter consists of a float 2.5 meter in diameter, connected by a rope to a seabed-mounted piston pump, installed on 25 meter deep water 2,5 km offshore Hanstholm, Denmark. The converter is designed to absorb an average maximum power of 1 kW. Measured data in real sea conditions are compared to results based on computer simulations and previous tank testing. Losses caused by rope elasticity and hysteresis, friction in the pump and back flow through the valves are assessed. The economic perspectives of a large wave power plant are presented, based on a revised prototype incorporating the results and experience gained during the test period. The wave energy conversion test `Hanstholm phase 2B` has showed, that it it technically possible to exploit the offshore wave energy resource. This source of energy could become attractive for commercial enterprise. The wave power converter demonstrated a reliable performance over a period of nine months. It produced energy under all wave conditions and survived storm waves of 9,6 m. A 300 MW wave power plant in the Danish part of the North sea is estimated to produce electricity at a cost between 2,1 - 2,4 DKK/kWh. The electrical transmission to shore contribute to approximately 20% of the cost. New data predict a potential of 23 kW per meter wave front. The energy plan Energy 21 proposed by the Danish Department of Energy, includes a scenario incorporating wave energy in the energy system year 2030. A strategy for the development of wave energy, has been proposed as part of the project OWEC-1 supported by the European Joule R and D programme. A proposal for future Danish initiatives to develop second generation point absorber systems is outlined. (ARW) 29 refs.

A maximally informative version of inelastic scattering of electromagnetic waves by Langmuir waves

International Nuclear Information System (INIS)

Erofeev, V. I.

2015-01-01

The concept of informativeness of nonlinear plasma physics scenarios is explained. Natural ideas of developing highly informative models of plasma kinetics are spelled out. A maximally informative version of inelastic scattering of electromagnetic waves by Langmuir waves in a weakly turbulent inhomogeneous plasma is developed with consideration of possible changes in wave polarization. In addition, a new formula for wave drift in spatial positions and wave vectors is derived. New scenarios of the respective wave drift and inelastic scattering are compared with the previous visions. The results indicate the need for further revision of the traditional understanding of nonlinear plasma phenomena

Assimilation of Wave Imaging Radar Observations for Real-time Wave-by-Wave Forecasting

Energy Technology Data Exchange (ETDEWEB)

Simpson, Alexandra [Oregon State Univ., Corvallis, OR (United States); Haller, Merrick [Oregon State Univ., Corvallis, OR (United States). School of Civil & Construction Engineering; Walker, David [SRI International, Menlo Park, CA (United States); Lynett, Pat [Univ. of Southern California, Los Angeles, CA (United States)

2017-08-29

-resolved predictions. Two recommendations for future work are as follows: first, we would recommend additional focused field campaigns for algorithm validation. The field campaign should be long enough to capture a range of wave conditions relevant to the target application and WEC site. In addition, it will be crucial to make sure the vessel of choice has high accuracy position and heading instrumentation (this instrumentation is commercially available but not standard on commercial fishing vessels). The second recommendation is to expand the model physics in the wave model backbone to include some nonlinear effects. Specifically, the third-order correction to the wave speed due to amplitude dispersion would be the next step in order to more accurately represent the phase speeds of large amplitude waves.

BCVEGPY2.0: An upgraded version of the generator BCVEGPY with the addition of hadroproduction of the P-wave B states

Science.gov (United States)

Chang, Chao-Hsi; Wang, Jian-Xiong; Wu, Xing-Gang

2006-02-01

physical problem: Hadronic production of B meson itself and its excited states. Method of solution: The code with option can generate weighted and unweighted events. For jet hadronization, an interface to PYTHIA is provided. Reason for the new version: There are two reasons. One is to provide additional codes for the hadronic production of P-wave excited B states: the four via color-singlet P-wave state directly and the two via color-octet S-wave state accordingly. The other one is to decompose the color-flow factor for the amplitude by an approximate way, that is adopted in PYTHIA. Summary of Revisions: (1) The integration efficiency over the momentum fractions of the initial partons x and x are improved; (2) The amplitudes for the hadronic production of the color-singlet components corresponding to the four P-wave states, BcJ,L=1∗ or P1 and P3 ( J=0,1,2), are included; (3) The amplitudes for P-wave production via the two color-octet components |((S1)g> and |((S3)g> are included; (4) For comparison, the S-wave ( S1 and S3) hadronic production via the light quark-antiquark annihilation mechanism is also included; (5) For convenience, 24 data files to record the information of the generated events in one run are added; (6) An additional file, parameter.for, is added to set the initial values of the parameters; (7) Two new parameters 'IMIX' (IMIX = 0 or 1) and 'IMIXTYPE' (IMIXTYPE = 1, = 2 or = 3) are added to meet the needs of generating the events for simulating 'mixing' or 'separate' event samples for various B and its excited states correctly; (8) One switch, 'IVEGGRADE', is added to determine whether to use the existed importance sampling function to generate a more precise importance sampling function or not; (9) Two parameters, 'IOUTPDF' and 'IPDFNUM', are added to determine which type of PDFs to use; (10) The color-flow decomposition for the amplitudes is rewritten by an approximate way, that is adopted in PYTHIA. Restrictions on the complexity of the problem: The

Wave Meteorology and Soaring

Science.gov (United States)

Wiley, Scott

2008-01-01

This viewgraph document reviews some mountain wave turbulence and operational hazards while soaring. Maps, photographs, and satellite images of the meteorological phenomena are included. Additionally, photographs of aircraft that sustained mountain wave damage are provided.

Diffusion, capture and recycling of SCAR/WAVE and Arp2/3 complexes observed in cells by single-molecule imaging

Science.gov (United States)

Millius, Arthur; Watanabe, Naoki; Weiner, Orion D.

2012-01-01

The SCAR/WAVE complex drives lamellipodium formation by enhancing actin nucleation by the Arp2/3 complex. Phosphoinositides and Rac activate the SCAR/WAVE complex, but how SCAR/WAVE and Arp2/3 complexes converge at sites of nucleation is unknown. We analyzed the single-molecule dynamics of WAVE2 and p40 (subunits of the SCAR/WAVE and Arp2/3 complexes, respectively) in XTC cells. We observed lateral diffusion of both proteins and captured the transition of p40 from diffusion to network incorporation. These results suggest that a diffusive 2D search facilitates binding of the Arp2/3 complex to actin filaments necessary for nucleation. After nucleation, the Arp2/3 complex integrates into the actin network and undergoes retrograde flow, which results in its broad distribution throughout the lamellipodium. By contrast, the SCAR/WAVE complex is more restricted to the cell periphery. However, with single-molecule imaging, we also observed WAVE2 molecules undergoing retrograde motion. WAVE2 and p40 have nearly identical speeds, lifetimes and sites of network incorporation. Inhibition of actin retrograde flow does not prevent WAVE2 association and disassociation with the membrane but does inhibit WAVE2 removal from the actin cortex. Our results suggest that membrane binding and diffusion expedites the recruitment of nucleation factors to a nucleation site independent of actin assembly, but after network incorporation, ongoing actin polymerization facilitates recycling of SCAR/WAVE and Arp2/3 complexes. PMID:22349699

Wave-processing of long-scale information by neuronal chains.

Directory of Open Access Journals (Sweden)

José Antonio Villacorta-Atienza

Full Text Available Investigation of mechanisms of information handling in neural assemblies involved in computational and cognitive tasks is a challenging problem. Synergetic cooperation of neurons in time domain, through synchronization of firing of multiple spatially distant neurons, has been widely spread as the main paradigm. Complementary, the brain may also employ information coding and processing in spatial dimension. Then, the result of computation depends also on the spatial distribution of long-scale information. The latter bi-dimensional alternative is notably less explored in the literature. Here, we propose and theoretically illustrate a concept of spatiotemporal representation and processing of long-scale information in laminar neural structures. We argue that relevant information may be hidden in self-sustained traveling waves of neuronal activity and then their nonlinear interaction yields efficient wave-processing of spatiotemporal information. Using as a testbed a chain of FitzHugh-Nagumo neurons, we show that the wave-processing can be achieved by incorporating into the single-neuron dynamics an additional voltage-gated membrane current. This local mechanism provides a chain of such neurons with new emergent network properties. In particular, nonlinear waves as a carrier of long-scale information exhibit a variety of functionally different regimes of interaction: from complete or asymmetric annihilation to transparent crossing. Thus neuronal chains can work as computational units performing different operations over spatiotemporal information. Exploiting complexity resonance these composite units can discard stimuli of too high or too low frequencies, while selectively compress those in the natural frequency range. We also show how neuronal chains can contextually interpret raw wave information. The same stimulus can be processed differently or identically according to the context set by a periodic wave train injected at the opposite end of the

Benchmarking spliced alignment programs including Spaln2, an extended version of Spaln that incorporates additional species-specific features.

Science.gov (United States)

Iwata, Hiroaki; Gotoh, Osamu

2012-11-01

Spliced alignment plays a central role in the precise identification of eukaryotic gene structures. Even though many spliced alignment programs have been developed, recent rapid progress in DNA sequencing technologies demands further improvements in software tools. Benchmarking algorithms under various conditions is an indispensable task for the development of better software; however, there is a dire lack of appropriate datasets usable for benchmarking spliced alignment programs. In this study, we have constructed two types of datasets: simulated sequence datasets and actual cross-species datasets. The datasets are designed to correspond to various real situations, i.e. divergent eukaryotic species, different types of reference sequences, and the wide divergence between query and target sequences. In addition, we have developed an extended version of our program Spaln, which incorporates two additional features to the scoring scheme of the original version, and examined this extended version, Spaln2, together with the original Spaln and other representative aligners based on our benchmark datasets. Although the effects of the modifications are not individually striking, Spaln2 is consistently most accurate and reasonably fast in most practical cases, especially for plants and fungi and for increasingly divergent pairs of target and query sequences.

Demonstration of the Recent Additions in Modeling Capabilities for the WEC-Sim Wave Energy Converter Design Tool: Preprint

Energy Technology Data Exchange (ETDEWEB)

Tom, N.; Lawson, M.; Yu, Y. H.

2015-03-01

WEC-Sim is a mid-fidelity numerical tool for modeling wave energy conversion (WEC) devices. The code uses the MATLAB SimMechanics package to solve the multi-body dynamics and models the wave interactions using hydrodynamic coefficients derived from frequency domain boundary element methods. In this paper, the new modeling features introduced in the latest release of WEC-Sim will be presented. The first feature discussed is the conversion of the fluid memory kernel to a state-space approximation that provides significant gains in computational speed. The benefit of the state-space calculation becomes even greater after the hydrodynamic body-to-body coefficients are introduced as the number of interactions increases exponentially with the number of floating bodies. The final feature discussed is the capability toadd Morison elements to provide additional hydrodynamic damping and inertia. This is generally used as a tuning feature, because performance is highly dependent on the chosen coefficients. In this paper, a review of the hydrodynamic theory for each of the features is provided and successful implementation is verified using test cases.

Traveling Wave Modes of a Plane Layered Anelastic Earth

Science.gov (United States)

2016-05-20

grant, “Coupled Modes in Elastic Bottoms” (1) is the publication “Traveling wave modes of a plane layered anelastic earth ” accepted for...anelastic earth Robert I. Odom Applied Physics Laboratory and Department of Earth and Space Sciences University of Washington, 1013 NE 40th St., Seattle...contrast to a similar standing wave problem for the earth free oscillations (Tromp and Dahlen, 1990). Attenuation is commonly incorporated into synthetic

Gas transfer under breaking waves: experiments and an improved vorticity-based model

Directory of Open Access Journals (Sweden)

V. K. Tsoukala

2008-07-01

Full Text Available In the present paper a modified vorticity-based model for gas transfer under breaking waves in the absence of significant wind forcing is presented. A theoretically valid and practically applicable mathematical expression is suggested for the assessment of the oxygen transfer coefficient in the area of wave-breaking. The proposed model is based on the theory of surface renewal that expresses the oxygen transfer coefficient as a function of both the wave vorticity and the Reynolds wave number for breaking waves. Experimental data were collected in wave flumes of various scales: a small-scale experiments were carried out using both a sloping beach and a rubble-mound breakwater in the wave flume of the Laboratory of Harbor Works, NTUA, Greece; b large-scale experiments were carried out with a sloping beach in the wind-wave flume of Delft Hydraulics, the Netherlands, and with a three-layer rubble mound breakwater in the Schneideberg Wave Flume of the Franzius Institute, University of Hannover, Germany. The experimental data acquired from both the small- and large-scale experiments were in good agreement with the proposed model. Although the apparent transfer coefficients from the large-scale experiments were lower than those determined from the small-scale experiments, the actual oxygen transfer coefficients, as calculated using a discretized form of the transport equation, are in the same order of magnitude for both the small- and large-scale experiments. The validity of the proposed model is compared to experimental results from other researchers. Although the results are encouraging, additional research is needed, to incorporate the influence of bubble mediated gas exchange, before these results are used for an environmental friendly design of harbor works, or for projects involving waste disposal at sea.

Activity incorporation into zinc doped PWR oxides

International Nuclear Information System (INIS)

Maekelae, Kari

1998-01-01

Activity incorporation into the oxide layers of PWR primary circuit constructional materials has been studied in Halden since 1993. The first zinc injection tests showed that zinc addition resulted in thinner oxide layers on new metal surfaces and reduced further incorporation of activity into already existing oxides. These tests were continued to find out the effects of previous zinc additions on the pickup of activity onto the surface oxides which were subsequently exposed to zinc-free coolant. The results showed that previous zinc addition will continue to reduce the rate of Co-60 build-up on out-of-core surfaces in subsequent exposure to zinc-free coolants. However, the previous Zn free test was performed for a relatively short period of time and the water chemistry programme was continued to find out the long term effects for extended periods without zinc. The activity incorporation into the stainless steel oxides started to increase as soon as zinc dosing to the coolant was stopped. The Co-60 concentration was lowest on all of the coupons which were first oxidised in Zn containing primary coolant. After the zinc injection period the thickness of the oxides increased, but activity in the oxide films did not increase at the same rate. This could indicate that zinc in the oxide blocks the adsorption sites for Co-60 incorporation. The Co-60 incorporation rate into the oxides on Inconel 600 seemed to be linear whether the oxide was pre-oxidised with or without Zn. The results indicate that zinc can either replace or prevent cobalt transport in the oxides. The results show that for zinc injection to be effective it should be carried out continuously. Furthermore the actual mechanism by which Zn inhibits the activity incorporation into the oxides is still not clear. Therefore, additional work has to follow with specified materials to verify the conclusions drawn in this work. (author)

A Bayesian approach to multi-messenger astronomy: identification of gravitational-wave host galaxies

International Nuclear Information System (INIS)

Fan, XiLong; Messenger, Christopher; Heng, Ik Siong

2014-01-01

We present a general framework for incorporating astrophysical information into Bayesian parameter estimation techniques used by gravitational wave data analysis to facilitate multi-messenger astronomy. Since the progenitors of transient gravitational wave events, such as compact binary coalescences, are likely to be associated with a host galaxy, improvements to the source sky location estimates through the use of host galaxy information are explored. To demonstrate how host galaxy properties can be included, we simulate a population of compact binary coalescences and show that for ∼8.5% of simulations within 200 Mpc, the top 10 most likely galaxies account for a ∼50% of the total probability of hosting a gravitational wave source. The true gravitational wave source host galaxy is in the top 10 galaxy candidates ∼10% of the time. Furthermore, we show that by including host galaxy information, a better estimate of the inclination angle of a compact binary gravitational wave source can be obtained. We also demonstrate the flexibility of our method by incorporating the use of either the B or K band into our analysis.

Improved WKB radial wave functions in several bases

International Nuclear Information System (INIS)

Durand, B.; Durand, L.; Department of Physics, University of Wisconsin, Madison, Wisconsin 53706)

1986-01-01

We develop approximate WKB-like solutions to the radial Schroedinger equation for problems with an angular momentum barrier using Riccati-Bessel, Coulomb, and harmonic-oscillator functions as basis functions. The solutions treat the angular momentum singularity near the origin more accurately in leading approximation than the standard WKB solutions based on sine waves. The solutions based on Riccati-Bessel and free Coulomb wave functions continue smoothly through the inner turning point and are appropriate for scattering problems. The solutions based on oscillator and bound Coulomb wave functions incorporate both turning points smoothly and are particularly appropriate for bound-state problems; no matching of piecewise solutions using Airy functions is necessary

Higher Fock states and power counting in exclusive P-wave quarkonium decays

CERN Document Server

Bolz, J; Schuler, G A; Bolz, Jan; Kroll, Peter; Schuler, Gerhard A.

1998-01-01

Exclusive processes at large momentum transfer Q factor into perturbatively calculable short-distance parts and long-distance hadronic wave functions. Usually, only contributions from the leading Fock states have to be included to leading order in 1/Q. We show that for exclusive decays of P-wave quarkonia the contribution from the next-higher Fock state |Q Qbar g> contributes at the same order in 1/Q. We investigate how the constituent gluon attaches to the hard process in order to form colour-singlet final-state hadrons and argue that a single additional long-distance factor is sufficient to parametrize the size of its contribution. Incorporating transverse degrees of freedom and Sudakov factors, our results are perturbatively stable in the sense that soft phase-space contributions are largely suppressed. Explicit calculations yield good agreement with data on chi_{c J} decays into pairs of pions, kaons, and etas. We also comment on J/psi decays into two pions.

A numerical study of wave-current interaction through surface and bottom stresses: Coastal ocean response to Hurricane Fran of 1996

Science.gov (United States)

Xie, L.; Pietrafesa, L. J.; Wu, K.

2003-02-01

A three-dimensional wave-current coupled modeling system is used to examine the influence of waves on coastal currents and sea level. This coupled modeling system consists of the wave model-WAM (Cycle 4) and the Princeton Ocean Model (POM). The results from this study show that it is important to incorporate surface wave effects into coastal storm surge and circulation models. Specifically, we find that (1) storm surge models without coupled surface waves generally under estimate not only the peak surge but also the coastal water level drop which can also cause substantial impact on the coastal environment, (2) introducing wave-induced surface stress effect into storm surge models can significantly improve storm surge prediction, (3) incorporating wave-induced bottom stress into the coupled wave-current model further improves storm surge prediction, and (4) calibration of the wave module according to minimum error in significant wave height does not necessarily result in an optimum wave module in a wave-current coupled system for current and storm surge prediction.

ULF waves in the foreshock

Science.gov (United States)

Greenstadt, E. W.; Le, G.; Strangeway, R. J.

1995-01-01

We review our current knowledge of ULF waves in planetary foreshocks. Most of this knowledge comes from observations taken within a few Earth radii of the terrestrial bow shock. Terrestrial foreshock ULF waves can be divided into three types, large amplitude low frequency waves (approximately 30-s period), upstream propagating whistlers (1-Hz waves), and 3-s waves. The 30-s waves are apparently generated by back-streaming ion beams, while the 1-Hz waves are generated at the bow shock. The source of the 3-s waves has yet to be determined. In addition to issues concerning the source of ULF waves in the foreshock, the waves present a number of challenges, both in terms of data acquisition, and comparison with theory. The various waves have different coherence scales, from approximately 100 km to approximately 1 Earth radius. Thus multi-spacecraft separation strategies must be tailored to the phenomenon of interest. From a theoretical point of view, the ULF waves are observed in a plasma in which the thermal pressure is comparable to the magnetic pressure, and the rest-frame wave frequency can be moderate fraction of the proton gyro-frequency. This requires the use of kinetic plasma wave dispersion relations, rather than multi-fluid MHD. Lastly, and perhaps most significantly, ULF waves are used to probe the ambient plasma, with inferences being drawn concerning the types of energetic ion distributions within the foreshock. However, since most of the data were acquired close to the bow shock, the properties of the more distant foreshock have to be deduced mainly through extrapolation of the near-shock results. A general understanding of the wave and plasma populations within the foreshock, their interrelation, and evolution, requires additional data from the more distant foreshock.

Generating asymptotically plane wave spacetimes

International Nuclear Information System (INIS)

Hubeny, Veronika E.; Rangamani, Mukund

2003-01-01

In an attempt to study asymptotically plane wave spacetimes which admit an event horizon, we find solutions to vacuum Einstein's equations in arbitrary dimension which have a globally null Killing field and rotational symmetry. We show that while such solutions can be deformed to include ones which are asymptotically plane wave, they do not posses a regular event horizon. If we allow for additional matter, such as in supergravity theories, we show that it is possible to have extremal solutions with globally null Killing field, a regular horizon, and which, in addition, are asymptotically plane wave. In particular, we deform the extremal M2-brane solution in 11-dimensional supergravity so that it behaves asymptotically as a 10-dimensional vacuum plane wave times a real line. (author)

Wave Engine Topping Cycle Assessment

Science.gov (United States)

Welch, Gerard E.

1996-01-01

The performance benefits derived by topping a gas turbine engine with a wave engine are assessed. The wave engine is a wave rotor that produces shaft power by exploiting gas dynamic energy exchange and flow turning. The wave engine is added to the baseline turboshaft engine while keeping high-pressure-turbine inlet conditions, compressor pressure ratio, engine mass flow rate, and cooling flow fractions fixed. Related work has focused on topping with pressure-exchangers (i.e., wave rotors that provide pressure gain with zero net shaft power output); however, more energy can be added to a wave-engine-topped cycle leading to greater engine specific-power-enhancement The energy addition occurs at a lower pressure in the wave-engine-topped cycle; thus the specific-fuel-consumption-enhancement effected by ideal wave engine topping is slightly lower than that effected by ideal pressure-exchanger topping. At a component level, however, flow turning affords the wave engine a degree-of-freedom relative to the pressure-exchanger that enables a more efficient match with the baseline engine. In some cases, therefore, the SFC-enhancement by wave engine topping is greater than that by pressure-exchanger topping. An ideal wave-rotor-characteristic is used to identify key wave engine design parameters and to contrast the wave engine and pressure-exchanger topping approaches. An aerodynamic design procedure is described in which wave engine design-point performance levels are computed using a one-dimensional wave rotor model. Wave engines using various wave cycles are considered including two-port cycles with on-rotor combustion (valved-combustors) and reverse-flow and through-flow four-port cycles with heat addition in conventional burners. A through-flow wave cycle design with symmetric blading is used to assess engine performance benefits. The wave-engine-topped turboshaft engine produces 16% more power than does a pressure-exchanger-topped engine under the specified topping

Modeling guided wave excitation in plates with surface mounted piezoelectric elements: coupled physics and normal mode expansion

Science.gov (United States)

Ren, Baiyang; Lissenden, Cliff J.

2018-04-01

Guided waves have been extensively studied and widely used for structural health monitoring because of their large volumetric coverage and good sensitivity to defects. Effectively and preferentially exciting a desired wave mode having good sensitivity to a certain defect is of great practical importance. Piezoelectric discs and plates are the most common types of surface-mounted transducers for guided wave excitation and reception. Their geometry strongly influences the proportioning between excited modes as well as the total power of the excited modes. It is highly desirable to predominantly excite the selected mode while the total transduction power is maximized. In this work, a fully coupled multi-physics finite element analysis, which incorporates the driving circuit, the piezoelectric element and the wave guide, is combined with the normal mode expansion method to study both the mode tuning and total wave power. The excitation of circular crested waves in an aluminum plate with circular piezoelectric discs is numerically studied for different disc and adhesive thicknesses. Additionally, the excitation of plane waves in an aluminum plate, using a stripe piezoelectric element is studied both numerically and experimentally. It is difficult to achieve predominant single mode excitation as well as maximum power transmission simultaneously, especially for higher order modes. However, guidelines for designing the geometry of piezoelectric elements for optimal mode excitation are recommended.

Spectral-element Seismic Wave Propagation on CUDA/OpenCL Hardware Accelerators

Science.gov (United States)

Peter, D. B.; Videau, B.; Pouget, K.; Komatitsch, D.

2015-12-01

Seismic wave propagation codes are essential tools to investigate a variety of wave phenomena in the Earth. Furthermore, they can now be used for seismic full-waveform inversions in regional- and global-scale adjoint tomography. Although these seismic wave propagation solvers are crucial ingredients to improve the resolution of tomographic images to answer important questions about the nature of Earth's internal processes and subsurface structure, their practical application is often limited due to high computational costs. They thus need high-performance computing (HPC) facilities to improving the current state of knowledge. At present, numerous large HPC systems embed many-core architectures such as graphics processing units (GPUs) to enhance numerical performance. Such hardware accelerators can be programmed using either the CUDA programming environment or the OpenCL language standard. CUDA software development targets NVIDIA graphic cards while OpenCL was adopted by additional hardware accelerators, like e.g. AMD graphic cards, ARM-based processors as well as Intel Xeon Phi coprocessors. For seismic wave propagation simulations using the open-source spectral-element code package SPECFEM3D_GLOBE, we incorporated an automatic source-to-source code generation tool (BOAST) which allows us to use meta-programming of all computational kernels for forward and adjoint runs. Using our BOAST kernels, we generate optimized source code for both CUDA and OpenCL languages within the source code package. Thus, seismic wave simulations are able now to fully utilize CUDA and OpenCL hardware accelerators. We show benchmarks of forward seismic wave propagation simulations using SPECFEM3D_GLOBE on CUDA/OpenCL GPUs, validating results and comparing performances for different simulations and hardware usages.

Semiconductor Quantum Electron Wave Transport, Diffraction, and Interference: Analysis, Device, and Measurement.

Science.gov (United States)

Henderson, Gregory Newell

Semiconductor device dimensions are rapidly approaching a fundamental limit where drift-diffusion equations and the depletion approximation are no longer valid. In this regime, quantum effects can dominate device response. To increase further device density and speed, new devices must be designed that use these phenomena to positive advantage. In addition, quantum effects provide opportunities for a new class of devices which can perform functions previously unattainable with "conventional" semiconductor devices. This thesis has described research in the analysis of electron wave effects in semiconductors and the development of methods for the design, fabrication, and characterization of quantum devices based on these effects. First, an exact set of quantitative analogies are presented which allow the use of well understood optical design and analysis tools for the development of electron wave semiconductor devices. Motivated by these analogies, methods are presented for modeling electron wave grating diffraction using both an exact rigorous coupled-wave analysis and approximate analyses which are useful for grating design. Example electron wave grating switch and multiplexer designs are presented. In analogy to thin-film optics, the design and analysis of electron wave Fabry-Perot interference filters are also discussed. An innovative technique has been developed for testing these (and other) electron wave structures using Ballistic Electron Emission Microscopy (BEEM). This technique uses a liquid-helium temperature scanning tunneling microscope (STM) to perform spectroscopy of the electron transmittance as a function of electron energy. Experimental results show that BEEM can resolve even weak quantum effects, such as the reflectivity of a single interface between materials. Finally, methods are discussed for incorporating asymmetric electron wave Fabry-Perot filters into optoelectronic devices. Theoretical and experimental results show that such structures could

Probabilistic seismic hazard estimates incorporating site effects - An example from Indiana, U.S.A

Science.gov (United States)

Hasse, J.S.; Park, C.H.; Nowack, R.L.; Hill, J.R.

2010-01-01

The U.S. Geological Survey (USGS) has published probabilistic earthquake hazard maps for the United States based on current knowledge of past earthquake activity and geological constraints on earthquake potential. These maps for the central and eastern United States assume standard site conditions with Swave velocities of 760 m/s in the top 30 m. For urban and infrastructure planning and long-term budgeting, the public is interested in similar probabilistic seismic hazard maps that take into account near-surface geological materials. We have implemented a probabilistic method for incorporating site effects into the USGS seismic hazard analysis that takes into account the first-order effects of the surface geologic conditions. The thicknesses of sediments, which play a large role in amplification, were derived from a P-wave refraction database with over 13, 000 profiles, and a preliminary geology-based velocity model was constructed from available information on S-wave velocities. An interesting feature of the preliminary hazard maps incorporating site effects is the approximate factor of two increases in the 1-Hz spectral acceleration with 2 percent probability of exceedance in 50 years for parts of the greater Indianapolis metropolitan region and surrounding parts of central Indiana. This effect is primarily due to the relatively thick sequence of sediments infilling ancient bedrock topography that has been deposited since the Pleistocene Epoch. As expected, the Late Pleistocene and Holocene depositional systems of the Wabash and Ohio Rivers produce additional amplification in the southwestern part of Indiana. Ground motions decrease, as would be expected, toward the bedrock units in south-central Indiana, where motions are significantly lower than the values on the USGS maps.

Improvements on Semi-Classical Distorted-Wave model

Energy Technology Data Exchange (ETDEWEB)

Sun Weili; Watanabe, Y.; Kuwata, R. [Kyushu Univ., Fukuoka (Japan); Kohno, M.; Ogata, K.; Kawai, M.

1998-03-01

A method of improving the Semi-Classical Distorted Wave (SCDW) model in terms of the Wigner transform of the one-body density matrix is presented. Finite size effect of atomic nuclei can be taken into account by using the single particle wave functions for harmonic oscillator or Wood-Saxon potential, instead of those based on the local Fermi-gas model which were incorporated into previous SCDW model. We carried out a preliminary SCDW calculation of 160 MeV (p,p`x) reaction on {sup 90}Zr with the Wigner transform of harmonic oscillator wave functions. It is shown that the present calculation of angular distributions increase remarkably at backward angles than the previous ones and the agreement with the experimental data is improved. (author)

Solitary wave and periodic wave solutions for the thermally forced gravity waves in atmosphere

International Nuclear Information System (INIS)

Li Ziliang

2008-01-01

By introducing a new transformation, a new direct and unified algebraic method for constructing multiple travelling wave solutions of general nonlinear evolution equations is presented and implemented in a computer algebraic system, which extends Fan's direct algebraic method to the case when r > 4. The solutions of a first-order nonlinear ordinary differential equation with a higher degree nonlinear term and Fan's direct algebraic method of obtaining exact solutions to nonlinear partial differential equations are applied to the combined KdV-mKdV-GKdV equation, which is derived from a simple incompressible non-hydrostatic Boussinesq equation with the influence of thermal forcing and is applied to investigate internal gravity waves in the atmosphere. As a result, by taking advantage of the new first-order nonlinear ordinary differential equation with a fifth-degree nonlinear term and an eighth-degree nonlinear term, periodic wave solutions associated with the Jacobin elliptic function and the bell and kink profile solitary wave solutions are obtained under the effect of thermal forcing. Most importantly, the mechanism of propagation and generation of the periodic waves and the solitary waves is analysed in detail according to the values of the heating parameter, which show that the effect of heating in atmosphere helps to excite westerly or easterly propagating periodic internal gravity waves and internal solitary waves in atmosphere, which are affected by the local excitation structures in atmosphere. In addition, as an illustrative sample, the properties of the solitary wave solution and Jacobin periodic solution are shown by some figures under the consideration of heating interaction

Analysis of Waves

DEFF Research Database (Denmark)

Frigaard, Peter; Andersen, Thomas Lykke

The present book describes the most important aspects of wave analysis techniques applied to physical model tests. Moreover, the book serves as technical documentation for the wave analysis software WaveLab 3, cf. Aalborg University (2012). In that respect it should be mentioned that supplementary...... to the present technical documentation exists also the online help document describing the WaveLab software in detail including all the inputs and output fields. In addition to the two main authors also Tue Hald, Jacob Helm-Petersen and Morten Møller Jakobsen have contributed to the note. Their input is highly...... acknowledged. The outline of the book is as follows: • Chapter 2 and 3 describes analysis of waves in time and frequency domain. • Chapter 4 and 5 describes the separation of incident and reflected waves for the two-dimensional case. • Chapter 6 describes the estimation of the directional spectra which also...

Five Waves of Innovation

DEFF Research Database (Denmark)

Østergaard, Claus Møller; Rosenstand, Claus Andreas Foss; Gertsen, Frank

2012-01-01

Building on previous well-argued work by Jon Sundbo (1995a), on how innovation has evolved in three phases or waves since 1880, this paper’s contribution is extending the historical line, by offering arguments and explanations for two additional waves of innovation that explain the most recent...... developments. The paper also adds new interpretations of the previous work by Sundbo (1995a) in suggesting that the waves are triggered by societal and economic crisis. The result is a new theoretical and historical framework, proposing five waves of innovation triggered by societal and economic crises...

Enhancing Wave Energy Competitiveness through Co-Located Wind and Wave Energy Farms. A Review on the Shadow Effect

Directory of Open Access Journals (Sweden)

Sharay Astariz

2015-07-01

Full Text Available Wave energy is one of the most promising alternatives to fossil fuels due to the enormous available resource; however, its development may be slowed as it is often regarded as uneconomical. The largest cost reductions are expected to be obtained through economies of scale and technological progress. In this sense, the incorporation of wave energy systems into offshore wind energy farms is an opportunity to foster the development of wave energy. The synergies between both renewables can be realised through these co-located energy farms and, thus, some challenges of offshore wind energy can be met. Among them, this paper focuses on the longer non-operational periods of offshore wind turbines—relative to their onshore counterparts—typically caused by delays in maintenance due to the harsh marine conditions. Co-located wave energy converters would act as a barrier extracting energy from the waves and resulting in a shielding effect over the wind farm. On this basis, the aim of this paper is to analyse wave energy economics in a holistic way, as well as the synergies between wave and offshore wind energy, focusing on the shadow effect and the associated increase in the accessibility to the wind turbines.

Spinal Cord Injuries in Wave-Riding Sports: The Influence of Environmental and Sport-Specific Factors.

Science.gov (United States)

Falconi, Audrey; Flick, David; Ferguson, Jason; Glorioso, John E

2016-01-01

Spinal cord injury is a nonfatal, catastrophic consequence of wave-riding sports. With surfing at the core, a multitude of activities have evolved that attempt to harness the power of ocean waves. The unique qualities of each wave-riding sport, in combination with the environmental factors of the ocean, define the risk for potential injuries. As wave-riding sports have become more advanced, athletes continue to push physical barriers. Taller waves are attempted while incorporating aerial maneuvers, all without protective equipment.

Scattering of internal gravity waves

OpenAIRE

Leaman Nye, Abigail

2011-01-01

Internal gravity waves play a fundamental role in the dynamics of stably stratified regions of the atmosphere and ocean. In addition to the radiation of momentum and energy remote from generation sites, internal waves drive vertical transport of heat and mass through the ocean by wave breaking and the mixing subsequently produced. Identifying regions where internal gravity waves contribute to ocean mixing and quantifying this mixing are therefore important for accurate climate ...

Experimental methods of shock wave research

CERN Document Server

Seiler, Friedrich

2016-01-01

This comprehensive and carefully edited volume presents a variety of experimental methods used in Shock Waves research. In 14 self contained chapters this 9th volume of the “Shock Wave Science and Technology Reference Library” presents the experimental methods used in Shock Tubes, Shock Tunnels and Expansion Tubes facilities. Also described is their set-up and operation. The uses of an arc heated wind tunnel and a gun tunnel are also contained in this volume. Whenever possible, in addition to the technical description some typical scientific results obtained using such facilities are described. Additionally, this authoritative book includes techniques for measuring physical properties of blast waves and laser generated shock waves. Information about active shock wave laboratories at different locations around the world that are not described in the chapters herein is given in the Appendix, making this book useful for every researcher involved in shock/blast wave phenomena.

The Virtual Wave Observatory (VWO): A Portal to Heliophysics Wave Data

Science.gov (United States)

Fung, Shing F.

2010-01-01

The Virtual Wave Observatory (VWO) is one of the discipline-oriented virtual observatories that help form the nascent NASA Heliophysics Data environment to support heliophysics research. It focuses on supporting the searching and accessing of distributed heliophysics wave data and information that are available online. Since the occurrence of a natural wave phenomenon often depends on the underlying geophysical -- i.e., context -- conditions under which the waves are generated and propagate, and the observed wave characteristics can also depend on the location of observation, VWO will implement wave-data search-by-context conditions and location, in addition to searching by time and observing platforms (both space-based and ground-based). This paper describes the VWO goals, the basic design objectives, and the key VWO functionality to be expected. Members of the heliophysics community are invited to participate in VWO development in order to ensure its usefulness and success.

Enhanced coupling of the fast wave to electrons through mode conversion to the ion hybrid wave

International Nuclear Information System (INIS)

Lashmore-Davies, C.N.; Fuchs, V.; Ram, A.K.; Bers, A.

1996-07-01

The mode conversion of the fast compressional Alfven wave to the ion hybrid wave is analyzed with particular reference to a plasma with two ion species present in approximately equal proportions. Two configurations are considered, the first referring to the usual resonance-cut-off case and the second to a cut-off-resonance-cut-off situation. The optimum conditions for maximising the mode converted energy are given. The second order fast wave equation is generalised to include the effect of the parallel electric field. Hence, all ion and electron loss mechanisms for the fast wave are incorporated, including mode conversion at the two-ion hybrid resonance. The significance of the approximate equality of the two ion species concentrations is that the mode converted ion hybrid wave is damped only by the electrons. The damping of the ion hybrid wave is described with the aid of the local dispersion relation and by means of a toroidal ray tracing code. In particular, the ray tracing calculation shows that the mode converted energy is totally absorbed by the electrons close to the two-ion hybrid resonance. The generalised fast wave equation is solved to determine how much energy is lost from the fast wave, incident from the low field side, before it encounters the two-ion hybrid resonance. For comparable concentrations of the two ion species, the mode converted power can be separated from the power directly absorbed by the ions and electrons from the fast wave. This allows the conditions to be ascertained under which strong electron heating through mode conversion dominates the direct dissipation of the fast wave. (UK)

Prospects and applicability of wave energy for South Africa

Science.gov (United States)

Lavidas, George; Venugopal, Vengatesan

2018-03-01

Renewable energy offers significant opportunities for electricity diversification. South Africa belongs to the group of developing nations and encompasses a lot of potential for renewable energy developments. Currently, the majority of its electricity production originates from fossil fuels; however, incorporation of clean coal technologies will aid in reaching the assigned targets. This study offers a long-term wave power quantification analysis with a numerical wave model. The investigation includes long-term resource assessment in the region, variability, seasonal and monthly wave energy content. Locations with high-energy content but low variability pose an opportunity that can contribute in the alleviation of energy poverty. Application of wave converters depends on the combination of complex terms. The study presents resource levels and the joint distributions, which indicate suitability for converter selection. Depending on the region of interest, these characteristics change. Thus, this resource assessment adds knowledge on wave power and optimal consideration for wave energy applicability.

Enhancing the performance of model-based elastography by incorporating additional a priori information in the modulus image reconstruction process

International Nuclear Information System (INIS)

Doyley, Marvin M; Srinivasan, Seshadri; Dimidenko, Eugene; Soni, Nirmal; Ophir, Jonathan

2006-01-01

Model-based elastography is fraught with problems owing to the ill-posed nature of the inverse elasticity problem. To overcome this limitation, we have recently developed a novel inversion scheme that incorporates a priori information concerning the mechanical properties of the underlying tissue structures, and the variance incurred during displacement estimation in the modulus image reconstruction process. The information was procured by employing standard strain imaging methodology, and introduced in the reconstruction process through the generalized Tikhonov approach. In this paper, we report the results of experiments conducted on gelatin phantoms to evaluate the performance of modulus elastograms computed with the generalized Tikhonov (GTK) estimation criterion relative to those computed by employing the un-weighted least-squares estimation criterion, the weighted least-squares estimation criterion and the standard Tikhonov method (i.e., the generalized Tikhonov method with no modulus prior). The results indicate that modulus elastograms computed with the generalized Tikhonov approach had superior elastographic contrast discrimination and contrast recovery. In addition, image reconstruction was more resilient to structural decorrelation noise when additional constraints were imposed on the reconstruction process through the GTK method

On condensation-induced waves

NARCIS (Netherlands)

Cheng, W.; Luo, X.; Dongen, van M.E.H.

2010-01-01

Complex wave patterns caused by unsteady heat release due to cloud formation in confined compressible flows are discussed. Two detailed numerical studies of condensation-induced waves are carried out. First, the response of a flow of nitrogen in a slender Laval nozzle to a sudden addition of water

Gravitational waves from supernova matter

International Nuclear Information System (INIS)

Scheidegger, S; Whitehouse, S C; Kaeppeli, R; Liebendoerfer, M

2010-01-01

We have performed a set of 11 three-dimensional magnetohydrodynamical (MHD) core-collapse supernova simulations in order to investigate the dependences of the gravitational wave signal on the progenitor's initial conditions. We study the effects of the initial central angular velocity and different variants of neutrino transport. Our models are started up from a 15M o-dot progenitor and incorporate an effective general relativistic gravitational potential and a finite temperature nuclear equation of state. Furthermore, the electron flavour neutrino transport is tracked by efficient algorithms for the radiative transfer of massless fermions. We find that non- and slowly rotating models show gravitational wave emission due to prompt- and lepton driven convection that reveals details about the hydrodynamical state of the fluid inside the protoneutron stars. Furthermore we show that protoneutron stars can become dynamically unstable to rotational instabilities at T/|W| values as low as ∼2% at core bounce. We point out that the inclusion of deleptonization during the postbounce phase is very important for the quantitative gravitational wave (GW) prediction, as it enhances the absolute values of the gravitational wave trains up to a factor of ten with respect to a lepton-conserving treatment.

Springing response due to bidirectional wave excitation

DEFF Research Database (Denmark)

Vidic-Perunovic, Jelena

2005-01-01

theories deal with the unidirectional wave excitation. This is quite standard. The problem is how to include more than one directional wave systems described by a wave spectrum with arbitrary heading. The main objective of the present work has been to account for the additional second-order springing......-linear (second order) high frequency springing analyses with unidirectional wave excitation are much more scattered. Some of the reasons are different level of wave excitation accounted in the different Executive Summary ivtheories, inclusion of additional hydrodynamic phenomena e.g. slamming in the time...... because, to the author's knowledge, this is the first time that the wave data were collected simultaneously with stress records on the deck of the ship. This is highly appreciated because one can use the precise input and not only the most probable sea state statistics. The actual picture of the sea waves...

On the use of higher order wave forms in the search for gravitational waves emitted by compact binary coalescences

Science.gov (United States)

McKechan, David J. A.

2010-11-01

This thesis concerns the use, in gravitational wave data analysis, of higher order wave form models of the gravitational radiation emitted by compact binary coalescences. We begin with an introductory chapter that includes an overview of the theory of general relativity, gravitational radiation and ground-based interferometric gravitational wave detectors. We then discuss, in Chapter 2, the gravitational waves emitted by compact binary coalescences, with an explanation of higher order waveforms and how they differ from leading order waveforms we also introduce the post-Newtonian formalism. In Chapter 3 the method and results of a gravitational wave search for low mass compact binary coalescences using a subset of LIGO's 5th science run data are presented and in the subsequent chapter we examine how one could use higher order waveforms in such analyses. We follow the development of a new search algorithm that incorporates higher order waveforms with promising results for detection efficiency and parameter estimation. In Chapter 5, a new method of windowing time-domain waveforms that offers benefit to gravitational wave searches is presented. The final chapter covers the development of a game designed as an outreach project to raise public awareness and understanding of the search for gravitational waves.

Properties of waves in an ion-beam plasma system

International Nuclear Information System (INIS)

Zank, G.P.; McKenzie, J.F.

1988-01-01

A multi-fluid approach is used to describe electrostatic interactions in an ion-beam plasma system. The structure of the wave equation governing the system exhibits the anisotropic and dispersive nature of the waves, whose properties are analysed in terms of the dispersion relation. The main purpose is to classify the different waves that can arise in an ion-beam plasma system in a systematic fashion. The classification is facilitated by introducing a three-parameter CMA diagram that illustrates the topological changes in not only the wavenumber, or refractive-index, surface but also the ray-velocity surface. Furthermore, an analytic expression governing wave amplification in an ion beam plasma is incorporated within the framework of a generalized CMA diagram. Such a description provides a simple interpretation for the onset of wave amplification in terms of a topological change in the refractive-index surface. It is hoped that by collating the wave properties in a unified form, many of the complicated wave features observed in an experiment may be interpreted more easily. (author)

Droplet networks with incorporated protein diodes show collective properties

Science.gov (United States)

Maglia, Giovanni; Heron, Andrew J.; Hwang, William L.; Holden, Matthew A.; Mikhailova, Ellina; Li, Qiuhong; Cheley, Stephen; Bayley, Hagan

2009-07-01

Recently, we demonstrated that submicrolitre aqueous droplets submerged in an apolar liquid containing lipid can be tightly connected by means of lipid bilayers to form networks. Droplet interface bilayers have been used for rapid screening of membrane proteins and to form asymmetric bilayers with which to examine the fundamental properties of channels and pores. Networks, meanwhile, have been used to form microscale batteries and to detect light. Here, we develop an engineered protein pore with diode-like properties that can be incorporated into droplet interface bilayers in droplet networks to form devices with electrical properties including those of a current limiter, a half-wave rectifier and a full-wave rectifier. The droplet approach, which uses unsophisticated components (oil, lipid, salt water and a simple pore), can therefore be used to create multidroplet networks with collective properties that cannot be produced by droplet pairs.

Nonlinear lattice waves in heterogeneous media

International Nuclear Information System (INIS)

Laptyeva, T V; Ivanchenko, M V; Flach, S

2014-01-01

We discuss recent advances in the understanding of the dynamics of nonlinear lattice waves in heterogeneous media, which enforce complete wave localization in the linear wave equation limit, especially Anderson localization for random potentials, and Aubry–André localization for quasiperiodic potentials. Additional nonlinear terms in the wave equations can either preserve the phase-coherent localization of waves, or destroy it through nonintegrability and deterministic chaos. Spreading wave packets are observed to show universal features in their dynamics which are related to properties of nonlinear diffusion equations. (topical review)

RF Wave Simulation Using the MFEM Open Source FEM Package

Science.gov (United States)

Stillerman, J.; Shiraiwa, S.; Bonoli, P. T.; Wright, J. C.; Green, D. L.; Kolev, T.

2016-10-01

A new plasma wave simulation environment based on the finite element method is presented. MFEM, a scalable open-source FEM library, is used as the basis for this capability. MFEM allows for assembling an FEM matrix of arbitrarily high order in a parallel computing environment. A 3D frequency domain RF physics layer was implemented using a python wrapper for MFEM and a cold collisional plasma model was ported. This physics layer allows for defining the plasma RF wave simulation model without user knowledge of the FEM weak-form formulation. A graphical user interface is built on πScope, a python-based scientific workbench, such that a user can build a model definition file interactively. Benchmark cases have been ported to this new environment, with results being consistent with those obtained using COMSOL multiphysics, GENRAY, and TORIC/TORLH spectral solvers. This work is a first step in bringing to bear the sophisticated computational tool suite that MFEM provides (e.g., adaptive mesh refinement, solver suite, element types) to the linear plasma-wave interaction problem, and within more complicated integrated workflows, such as coupling with core spectral solver, or incorporating additional physics such as an RF sheath potential model or kinetic effects. USDoE Awards DE-FC02-99ER54512, DE-FC02-01ER54648.

Computer modeling of inelastic wave propagation in porous rock

International Nuclear Information System (INIS)

Cheney, J.A.; Schatz, J.F.; Snell, C.

1979-01-01

Computer modeling of wave propagation in porous rock has several important applications. Among them are prediction of fragmentation and permeability changes to be caused by chemical explosions used for in situ resource recovery, and the understanding of nuclear explosion effects such as seismic wave generation, containment, and site hardness. Of interest in all these applications are the distance from the source to which inelastic effects persist and the amount of porosity change within the inelastic region. In order to study phenomena related to these applications, the Cam Clay family of models developed at Cambridge University was used to develop a similar model that is applicable to wave propagation in porous rock. That model was incorporated into a finite-difference wave propagation computer code SOC. 10 figures, 1 table

Probing the early universe with inflationary gravitational waves

International Nuclear Information System (INIS)

Boyle, Latham A.; Steinhardt, Paul J.

2008-01-01

Near comoving wave number k, the gravitational-wave background (GWB) from inflation carries information about the physical conditions near two moments in cosmic history: the moment when k 'left the horizon' during inflation, and the moment when it 're-entered the horizon' after inflation. We investigate the extent to which this information can be extracted if the GWB is measured by a combination of cosmic-microwave-background polarization experiments on large scales and space-based laser-interferometer experiments on small scales. To disentangle this information, we derive a new gravitational-wave transfer function that incorporates a number of physical effects that were treated less accurately, less generally, or were missing altogether in previous treatments. In particular, it incorporates: (i) dark energy with time-varying equation of state w(z); (ii) tensor anisotropic stress due to free-streaming relativistic particles in the early universe; and (iii) a variety of physical effects that cause deviations from the standard equation of state w=1/3 during the radiation era. Based on this transfer function, we consider the degree to which the GWB can be used to test inflation and to probe the 'primordial dark age' between the end of inflation and the electroweak phase transition.

Slow Waves in Fractures Filled with Viscous Fluid

Energy Technology Data Exchange (ETDEWEB)

Korneev, Valeri

2008-01-08

Stoneley guided waves in a fluid-filled fracture generally have larger amplitudes than other waves, and therefore, their properties need to be incorporated in more realistic models. In this study, a fracture is modeled as an infinite layer of viscous fluid bounded by two elastic half-spaces with identical parameters. For small fracture thickness, I obtain a simple dispersion equation for wave-propagation velocity. This velocity is much smaller than the velocity of a fluid wave in a Biot-type solution, in which fracture walls are assumed to be rigid. At seismic prospecting frequencies and realistic fracture thicknesses, the Stoneley guided wave has wavelengths on the order of several meters and an attenuation Q factor exceeding 10, which indicates the possibility of resonance excitation in fluid-bearing rocks. The velocity and attenuation of Stoneley guided waves are distinctly different at low frequencies for water and oil. The predominant role of fractures in fluid flow at field scales is supported by permeability data showing an increase of several orders of magnitude when compared to values obtained at laboratory scales. These data suggest that Stoneley guided waves should be taken into account in theories describing seismic wave propagation in fluid-saturated rocks.

3D Guided Wave Motion Analysis on Laminated Composites

Science.gov (United States)

Tian, Zhenhua; Leckey, Cara; Yu, Lingyu

2013-01-01

Ultrasonic guided waves have proved useful for structural health monitoring (SHM) and nondestructive evaluation (NDE) due to their ability to propagate long distances with less energy loss compared to bulk waves and due to their sensitivity to small defects in the structure. Analysis of actively transmitted ultrasonic signals has long been used to detect and assess damage. However, there remain many challenging tasks for guided wave based SHM due to the complexity involved with propagating guided waves, especially in the case of composite materials. The multimodal nature of the ultrasonic guided waves complicates the related damage analysis. This paper presents results from parallel 3D elastodynamic finite integration technique (EFIT) simulations used to acquire 3D wave motion in the subject laminated carbon fiber reinforced polymer composites. The acquired 3D wave motion is then analyzed by frequency-wavenumber analysis to study the wave propagation and interaction in the composite laminate. The frequency-wavenumber analysis enables the study of individual modes and visualization of mode conversion. Delamination damage has been incorporated into the EFIT model to generate "damaged" data. The potential for damage detection in laminated composites is discussed in the end.

Wave energy: a Pacific perspective.

Science.gov (United States)

Paasch, Robert; Ruehl, Kelley; Hovland, Justin; Meicke, Stephen

2012-01-28

This paper illustrates the status of wave energy development in Pacific rim countries by characterizing the available resource and introducing the region's current and potential future leaders in wave energy converter development. It also describes the existing licensing and permitting process as well as potential environmental concerns. Capabilities of Pacific Ocean testing facilities are described in addition to the region's vision of the future of wave energy.

Wave friction factor rediscovered

Science.gov (United States)

Le Roux, J. P.

2012-02-01

The wave friction factor is commonly expressed as a function of the horizontal water particle semi-excursion ( A wb) at the top of the boundary layer. A wb, in turn, is normally derived from linear wave theory by {{U_{{wb}}/T_{{w}}}}{{2π }} , where U wb is the maximum water particle velocity measured at the top of the boundary layer and T w is the wave period. However, it is shown here that A wb determined in this way deviates drastically from its real value under both linear and non-linear waves. Three equations for smooth, transitional and rough boundary conditions, respectively, are proposed to solve this problem, all three being a function of U wb, T w, and δ, the thickness of the boundary layer. Because these variables can be determined theoretically for any bottom slope and water depth using the deepwater wave conditions, there is no need to physically measure them. Although differing substantially from many modern attempts to define the wave friction factor, the results coincide with equations proposed in the 1960s for either smooth or rough boundary conditions. The findings also confirm that the long-held notion of circular water particle motion down to the bottom in deepwater conditions is erroneous, the motion in fact being circular at the surface and elliptical at depth in both deep and shallow water conditions, with only horizontal motion at the top of the boundary layer. The new equations are incorporated in an updated version (WAVECALC II) of the Excel program published earlier in this journal by Le Roux et al. Geo-Mar Lett 30(5): 549-560, (2010).

Multi-sample immunoassay inside optical fiber capillary enabled by evanescent wave detection

Directory of Open Access Journals (Sweden)

Chun-Wei Wang

2016-03-01

Full Text Available A novel evanescent wave-based (EW microfluidic capillary fiber-optic biosensor (MCFOB has been developed using capillaries as a transducer embedded in a multichannel device to enhance the collection efficiency of the fluorescence signal. The capillary serves dual roles as a waveguide and a container, enabling more straightforward, consistent, and compact biosensor packaging compared to conventional optical fiber biosensors and microfluidic systems. In order to detect multiple samples in one device, the biosensor incorporates a polydimethysiloxane (PDMS multi-channel device, which also serves as cladding for the biosensor. In addition, this biosensor only consumes 10 μl of a sample and does not require hydrofluoric acid etching in the fabrication process. The orientation for signal collection is optimized by comparing the lateral and normal signal directions for detected glyceraldehyde 3-phosphate dehydrogenase (GAPDH. C-reactive protein (CRP is used to validate the MCFOB, and the limit of detection (LOD for CRP in the MCFOB is 1.94 ng/ml (74 pM. Moreover, the real-time measurement is demonstrated to verify that the evanescent wave is the only exciting light source in the MCFOB, which gives the potential for real-time measurement applications. Keywords: C-reactive protein, Capillary, Fiber-optic, Microfluidic, Evanescent wave, Immunoassay

Lamb Wave Response of Fatigued Composite Samples

Science.gov (United States)

Seale, Michael; Smith, Barry T.; Prosser, William H.; Masters, John E.

1994-01-01

Composite materials are being more widely used today by aerospace, automotive, sports equipment, and a number of other commercial industries because of their advantages over conventional metals. Composites have a high strength-to-weight ratio and can be constructed to meet specific design needs. Composite structures are already in use in secondary parts of the Douglas MD-11 and are planned to be used in the new MD-12X. Plans also exist for their use in primary and secondary structures on the Boeing 777. Douglas proposed MD-XX may also incorporate composite materials into primary structures such as the wings and tail. Use of composites in these structures offers weight savings, corrosion resistance, and improved aerodynamics. Additionally, composites have been used to repair cracks in many B-1Bs where traditional repair techniques were not very effective. Plans have also been made to reinforce all of the remaining B-1s with composite materials. Verification of the structural integrity of composite components is needed to insure safe operation of these aerospace vehicles. One aspect of the use of these composites is their response to fatigue. To track this progression of fatigue in aerospace structures, a convenient method to nondestructively monitor this damage needs to be developed. Traditional NDE techniques used on metals are not easily adaptable to composites due to the inhomogeneous and anisotropic nature of these materials. Finding an effective means of nondestructively monitoring fatigue damage is extremely important to the safety and reliability of such structures. Lamb waves offer one method of evaluating these composite materials. As a material is fatigued, the modulus degrades. Since the Lamb wave velocity can be related to the modulus of the material, an effective tool can be developed to monitor fatigue damage in composites by measuring the velocity of these waves. In this work, preliminary studies have been conducted which monitor fatigue damage in

Wave Resource Characterization at US Wave Energy Converter (WEC) Test Sites

Science.gov (United States)

Dallman, A.; Neary, V. S.

2016-02-01

The US Department of Energy's (DOE) Marine and Hydrokinetic energy (MHK) Program is supporting a diverse research and development portfolio intended to accelerate commercialization of the marine renewable industry by improving technology performance, reducing market barriers, and lowering the cost of energy. Wave resource characterization at potential and existing wave energy converter (WEC) test sites and deployment locations contributes to this DOE goal by providing a catalogue of wave energy resource characteristics, met-ocean data, and site infrastructure information, developed utilizing a consistent methodology. The purpose of the catalogue is to enable the comparison of resource characteristics among sites to facilitate the selection of test sites that are most suitable for a developer's device and that best meet their testing needs and objectives. It also provides inputs for the design of WEC test devices and planning WEC tests, including the planning of deployment and operations and maintenance. The first edition included three sites: the Pacific Marine Energy Center (PMEC) North Energy Test Site (NETS) offshore of Newport, Oregon, the Kaneohe Bay Naval Wave Energy Test Site (WETS) offshore of Oahu, HI, and a potential site offshore of Humboldt Bay, CA (Eureka, CA). The second edition was recently finished, which includes five additional sites: the Jennette's Pier Wave Energy Converter Test Site in North Carolina, the US Army Corps of Engineers (USACE) Field Research Facility (FRF), the PMEC Lake Washington site, the proposed PMEC South Energy Test Site (SETS), and the proposed CalWave Central Coast WEC Test Site. The operational sea states are included according to the IEC Technical Specification on wave energy resource assessment and characterization, with additional information on extreme sea states, weather windows, and representative spectra. The methodology and a summary of results will be discussed.

Incorporation of exact boundary conditions into a discontinuous galerkin finite element method for accurately solving 2d time-dependent maxwell equations

KAUST Repository

Sirenko, Kostyantyn

2013-01-01

A scheme that discretizes exact absorbing boundary conditions (EACs) to incorporate them into a time-domain discontinuous Galerkin finite element method (TD-DG-FEM) is described. The proposed TD-DG-FEM with EACs is used for accurately characterizing transient electromagnetic wave interactions on two-dimensional waveguides. Numerical results demonstrate the proposed method\\'s superiority over the TD-DG-FEM that employs approximate boundary conditions and perfectly matched layers. Additionally, it is shown that the proposed method can produce the solution with ten-eleven digit accuracy when high-order spatial basis functions are used to discretize the Maxwell equations as well as the EACs. © 1963-2012 IEEE.

Fundamental plasma emission involving ion sound waves

International Nuclear Information System (INIS)

Cairns, I.H.

1987-01-01

The theory for fundamental plasma emission by the three-wave processes L ± S → T (where L, S and T denote Langmuir, ion sound and transverse waves, respectively) is developed. Kinematic constraints on the characteristics and growth lengths of waves participating in the wave processes are identified. In addition the rates, path-integrated wave temperatures, and limits on the brightness temperature of the radiation are derived. (author)

Modeling wave attenuation by salt marshes in Jamaica Bay, New York, using a new rapid wave model

Science.gov (United States)

Marsooli, Reza; Orton, Philip M.; Mellor, George

2017-07-01

Using a new rapid-computation wave model, improved and validated in the present study, we quantify the value of salt marshes in Jamaica Bay—a highly urbanized estuary located in New York City—as natural buffers against storm waves. We augment the MDO phase-averaged wave model by incorporating a vegetation-drag-induced energy dissipation term into its wave energy balance equation. We adopt an empirical formula from literature to determine the vegetation drag coefficient as a function of environmental conditions. Model evaluation using data from laboratory-scale experiments show that the improved MDO model accurately captures wave height attenuation due to submerged and emergent vegetation. We apply the validated model to Jamaica Bay to quantify the influence of coastal-scale salt marshes on storm waves. It is found that the impact of marsh islands is largest for storms with lower flood levels, due to wave breaking on the marsh island substrate. However, the role of the actual marsh plants, Spartina alterniflora, grows larger for storms with higher flood levels, when wave breaking does not occur and the vegetative drag becomes the main source of energy dissipation. For the latter case, seasonality of marsh height is important; at its maximum height in early fall, S. alterniflora causes twice the reduction as when it is at a shorter height in early summer. The model results also indicate that the vegetation drag coefficient varies 1 order of magnitude in the study area, and suggest exercising extra caution in using a constant drag coefficient in coastal wetlands.

Study on Rayleigh Wave Inversion for Estimating Shear-wave Velocity Profile

Directory of Open Access Journals (Sweden)

T.A. Sanny

2003-05-01

Full Text Available Rayleigh wave or ground roll is a noise in seismic body waves. However, how to use this noise for soil characterization is very interesting since Rayleigh wave phase velocity is a function of compression-wave velocity, shear-wave velocity, density and layer thickness. In layered-medium Rayleigh wave velocity also depends on wavelength or frequency, and this phenomenon is called dispersion. Inversion procedure to get shear-wave velocity profile needs a priori information about the solution of the problem to limit the unknown parameters. The Lagrange multiplier method was used to solve the constrained optimization problems or well known as a smoothing parameter in inversion problems. The advantage of our inversion procedure is that it can guarantee the convergence of solution even though the field data is incomplete, insufficient, and inconsistent. The addition of smoothing parameter can reduce the time to converge. Beside numerical stability, the statistical stability is also involved in inversion procedure. In field experiment we extracted ground roll data from seismic refraction record. The dispersion curves had been constructed by applying f-k analysis and f-k dip filtering. The dispersion curves show the dependence of Rayleigh wave phase velocities in layered media to frequency. The synthetic models also demonstrate the stability and the speed of inversion procedure.

Nonlinear Modeling and Analysis of Pressure Wave inside CEUP Fuel Pipeline

Directory of Open Access Journals (Sweden)

Qaisar Hayat

2014-01-01

Full Text Available Operating conditions dependent large pressure variations are one of the working characteristics of combination electronic unit pump (CEUP fuel injection system for diesel engines. We propose a precise and accurate nonlinear numerical model of pressure inside HP fuel pipeline of CEUP using wave equation (WE including both viscous and frequency dependent frictions. We have proved that developed hyperbolic approximation gives more realistic description of pressure wave as compared to classical viscous damped wave equation. Frictional effects of various frequencies on pressure wave have been averaged out across valid frequencies to represent the combined effect of all frequencies on pressure wave. Dynamic variations of key fuel properties including density, acoustic wave speed, and bulk modulus with varying pressures have also been incorporated. Based on developed model we present analysis on effect of fuel pipeline length on pressure wave propagation and variation of key fuel properties with both conventional diesel and alternate fuel rapeseed methyl ester (RME for CEUP pipeline.

Uncertainties in the 2004 Sumatra–Andaman source through nonlinear stochastic inversion of tsunami waves

Science.gov (United States)

Venugopal, M.; Roy, D.; Rajendran, K.; Guillas, S.; Dias, F.

2017-01-01

Numerical inversions for earthquake source parameters from tsunami wave data usually incorporate subjective elements to stabilize the search. In addition, noisy and possibly insufficient data result in instability and non-uniqueness in most deterministic inversions, which are barely acknowledged. Here, we employ the satellite altimetry data for the 2004 Sumatra–Andaman tsunami event to invert the source parameters. We also include kinematic parameters that improve the description of tsunami generation and propagation, especially near the source. Using a finite fault model that represents the extent of rupture and the geometry of the trench, we perform a new type of nonlinear joint inversion of the slips, rupture velocities and rise times with minimal a priori constraints. Despite persistently good waveform fits, large uncertainties in the joint parameter distribution constitute a remarkable feature of the inversion. These uncertainties suggest that objective inversion strategies should incorporate more sophisticated physical models of seabed deformation in order to significantly improve the performance of early warning systems. PMID:28989311

Shock waves in gas and plasma

International Nuclear Information System (INIS)

Niu, K.

1996-01-01

A shock wave is a discontinuous surface that connects supersonic flow with subsonic flow. After a shock wave, flow velocity is reduced, and pressure and temperature increase; entropy especially increases across a shock wave. Therefore, flow is in nonequilibrium, and irreversible processes occur inside the shock layer. The thickness of a shock wave in neutral gas is of the order of the mean free path of the fluid particle. A shock wave also appears in magnetized plasma. Provided that when the plasma flow is parallel to the magnetic field, a shock wave appears if the governing equation for velocity potential is in hyperbolic type in relation with the Mach number and the Alfven number. When the flow is perpendicular to the magnetic field, the Maxwell stress, in addition to the pressure, plays a role in the shock wave in plasma. When the plasma temperature is so high, as the plasma becomes collision-free, another type of shock wave appears. In a collision-free shock wave, gyromotions of electrons around the magnetic field lines cause the shock formation instead of collisions in a collision-dominant plasma or neutral gas. Regardless of a collision-dominant or collision-free shock wave, the fluid that passes through the shock wave is heated in addition to being compressed. In inertial confinement fusion, the fuel must be compressed. Really, implosion motion performs fuel compression. A shock wave, appearing in the process of implosion, compresses the fuel. The shock wave, however, heats the fuel more intensively, and it makes it difficult to compress the fuel further because high temperatures invite high pressure. Adiabatic compression of the fuel is the desired result during the implosion, without the formation of a shock wave. (Author)

Incorporation of T4 bacteriophage in electrospun fibres.

Science.gov (United States)

Korehei, R; Kadla, J

2013-05-01

Antibacterial food packaging materials, such as bacteriophage-activated electrospun fibrous mats, may address concerns triggered by waves of bacterial food contamination. To address this, we investigated several efficient methods for incorporating T4 bacteriophage into electrospun fibrous mats. The incorporation of T4 bacteriophage using simple suspension electrospinning led to more than five orders of magnitude decrease in bacteriophage activity. To better maintain bacteriophage viability, emulsion electrospinning was developed where the T4 bacteriophage was pre-encapsulated in an alginate reservoir via an emulsification process and subsequently electrospun into fibres. This resulted in an increase in bacteriophage viability, but there was still two orders of magnitude drop in activity. Using a coaxial electrospinning process, full bacteriophage activity could be maintained. In this process, a core/shell fibre structure was formed with the T4 bacteriophage being directly incorporated into the fibre core. The core/shell fibre encapsulated bacteriophage exhibited full bacteriophage viability after storing for several weeks at +4°C. Coaxial electrospinning was shown to be capable of encapsulating bacteriophages with high loading capacity, high viability and long storage time. These results are significant in the context of controlling and preventing bacterial infections in perishable foods during storage. © 2013 The Society for Applied Microbiology.

Pemodelan Desain Sol Sepatu dengan Inovasi Penambahan Wave Spring

Directory of Open Access Journals (Sweden)

Redyarsa Dharma Bintara

2015-07-01

Full Text Available Desain sepatu sport berkembang pesat dengan tujuan mengurangi cedera dan meningkatkankenyamanan pengguna. Pengurangan cedera dilakukan dengan cara memperbesar energi yangdiserap dari beban akibat pengguna berlari atau melompat. Pada penelitian ini dilakukanpenambahan wave spring yang digunakan sebagai mekanisme penyerap beban.Pemodelandilakukan pada sol sepatu dengan menggunakan bantuan software finite element method (FEMAnsys 14.5 Academic. Model awal dilakukan untuk mengetahui batas deformasi sol sepatu yangakan dimanfaatkan sebagai input model berikutnya yaitu model dengan diberikan inovasipenambahan wave spring. Analisa difokuskan pada sol sepatu bagian belakang (tumit kaki.Darihasil simulasi, didapatkan bahwa penyerapan energi sol sepatu dengan penambahan wave springlebih besar daripada penyerapan energi sol sepatu tanpa penambahan wave spring, sehinggapenambahan wave spring memungkinkan untuk diaplikasikan pada sol sepatu sport.Kata kunci: Penyerapan energi, wave spring, sol sepatu. Sport shoe design had been developed rapidly with the purpose to reduce injuries and increaseuser comfort. Reduction of injury is done by enlarging the energy absorbed from the user running orjumping load. In this study, the addition of the wave spring is used as the load absorbingmechanism. The shoes sole is modeled by using finite element method (FEM software Ansys 14.5Academic. Initial model was conducted to determine the deformation boundary in soles which willbe used as input to the next model for the wave spring addition innovation. Analysis focused onshoe sole on heel foot. From the simulation results, it was found that the energy absorption shoessoles with the addition of the wave spring is greater than the energy absorption soles without theaddition of wave spring. It can be concluded that the addition of a spring wave can be applied to thesoles of sports shoes.Keywords: Energy absorb, wave spring, shoe sole, deformation boundary

Wave Generation in Physical Models

DEFF Research Database (Denmark)

Andersen, Thomas Lykke; Frigaard, Peter

The present book describes the most important aspects of wave generation techniques in physical models. Moreover, the book serves as technical documentation for the wave generation software AwaSys 6, cf. Aalborg University (2012). In addition to the two main authors also Tue Hald and Michael...

An adjustable RF tuning element for microwave, millimeter wave, and submillimeter wave integrated circuits

Science.gov (United States)

Lubecke, Victor M.; Mcgrath, William R.; Rutledge, David B.

1991-01-01

Planar RF circuits are used in a wide range of applications from 1 GHz to 300 GHz, including radar, communications, commercial RF test instruments, and remote sensing radiometers. These circuits, however, provide only fixed tuning elements. This lack of adjustability puts severe demands on circuit design procedures and materials parameters. We have developed a novel tuning element which can be incorporated into the design of a planar circuit in order to allow active, post-fabrication tuning by varying the electrical length of a coplanar strip transmission line. It consists of a series of thin plates which can slide in unison along the transmission line, and the size and spacing of the plates are designed to provide a large reflection of RF power over a useful frequency bandwidth. Tests of this structure at 1 GHz to 3 Ghz showed that it produced a reflection coefficient greater than 0.90 over a 20 percent bandwidth. A 2 GHz circuit incorporating this tuning element was also tested to demonstrate practical tuning ranges. This structure can be fabricated for frequencies as high as 1000 GHz using existing micromachining techniques. Many commercial applications can benefit from this micromechanical RF tuning element, as it will aid in extending microwave integrated circuit technology into the high millimeter wave and submillimeter wave bands by easing constraints on circuit technology.

A novel method for predicting the power outputs of wave energy converters

Science.gov (United States)

Wang, Yingguang

2018-03-01

This paper focuses on realistically predicting the power outputs of wave energy converters operating in shallow water nonlinear waves. A heaving two-body point absorber is utilized as a specific calculation example, and the generated power of the point absorber has been predicted by using a novel method (a nonlinear simulation method) that incorporates a second order random wave model into a nonlinear dynamic filter. It is demonstrated that the second order random wave model in this article can be utilized to generate irregular waves with realistic crest-trough asymmetries, and consequently, more accurate generated power can be predicted by subsequently solving the nonlinear dynamic filter equation with the nonlinearly simulated second order waves as inputs. The research findings demonstrate that the novel nonlinear simulation method in this article can be utilized as a robust tool for ocean engineers in their design, analysis and optimization of wave energy converters.

Ocean wave energy conversion

CERN Document Server

McCormick, Michael E

2007-01-01

This volume will prove of vital interest to those studying the use of renewable resources. Scientists, engineers, and inventors will find it a valuable review of ocean wave mechanics as well as an introduction to wave energy conversion. It presents physical and mathematical descriptions of the nine generic wave energy conversion techniques, along with their uses and performance characteristics.Author Michael E. McCormick is the Corbin A. McNeill Professor of Naval Engineering at the U.S. Naval Academy. In addition to his timely and significant coverage of possible environmental effects associa

Dyakonov surface waves in lossy metamaterials

OpenAIRE

Sorní Laserna, Josep; Naserpour, Mahin; Zapata Rodríguez, Carlos Javier; Miret Marí, Juan José

2015-01-01

We analyze the existence of localized waves in the vicinities of the interface between two dielectrics, provided one of them is uniaxial and lossy. We found two families of surface waves, one of them approaching the well-known Dyakonov surface waves (DSWs). In addition, a new family of wave fields exists which are tightly bound to the interface. Although its appearance is clearly associated with the dissipative character of the anisotropic material, the characteristic propagation length of su...

The effects of core-reflected waves on finite fault inversions with teleseismic body wave data

Science.gov (United States)

Qian, Yunyi; Ni, Sidao; Wei, Shengji; Almeida, Rafael; Zhang, Han

2017-11-01

Teleseismic body waves are essential for imaging rupture processes of large earthquakes. Earthquake source parameters are usually characterized by waveform analyses such as finite fault inversions using only turning (direct) P and SH waves without considering the reflected phases from the core-mantle boundary (CMB). However, core-reflected waves such as ScS usually have amplitudes comparable to direct S waves due to the total reflection from the CMB and might interfere with the S waves used for inversion, especially at large epicentral distances for long duration earthquakes. In order to understand how core-reflected waves affect teleseismic body wave inversion results, we develop a procedure named Multitel3 to compute Green's functions that contain turning waves (direct P, pP, sP, direct S, sS and reverberations in the crust) and core-reflected waves (PcP, pPcP, sPcP, ScS, sScS and associated reflected phases from the CMB). This ray-based method can efficiently generate synthetic seismograms for turning and core-reflected waves independently, with the flexibility to take into account the 3-D Earth structure effect on the timing between these phases. The performance of this approach is assessed through a series of numerical inversion tests on synthetic waveforms of the 2008 Mw7.9 Wenchuan earthquake and the 2015 Mw7.8 Nepal earthquake. We also compare this improved method with the turning-wave only inversions and explore the stability of the new procedure when there are uncertainties in a priori information (such as fault geometry and epicentre location) or arrival time of core-reflected phases. Finally, a finite fault inversion of the 2005 Mw8.7 Nias-Simeulue earthquake is carried out using the improved Green's functions. Using enhanced Green's functions yields better inversion results as expected. While the finite source inversion with conventional P and SH waves is able to recover large-scale characteristics of the earthquake source, by adding PcP and ScS phases

Four-body correlation embedded in antisymmetrized geminal power wave function.

Science.gov (United States)

Kawasaki, Airi; Sugino, Osamu

2016-12-28

We extend the Coleman's antisymmetrized geminal power (AGP) to develop a wave function theory that can incorporate up to four-body correlation in a region of strong correlation. To facilitate the variational determination of the wave function, the total energy is rewritten in terms of the traces of geminals. This novel trace formula is applied to a simple model system consisting of one dimensional Hubbard ring with a site of strong correlation. Our scheme significantly improves the result obtained by the AGP-configuration interaction scheme of Uemura et al. and also achieves more efficient compression of the degrees of freedom of the wave function. We regard the result as a step toward a first-principles wave function theory for a strongly correlated point defect or adsorbate embedded in an AGP-based mean-field medium.

Identifying Coronary Artery Disease in Asymptomatic Middle-Aged Sportsmen: The Additional Value of Pulse Wave Velocity.

Directory of Open Access Journals (Sweden)

Thijs L Braber

Full Text Available Cardiovascular screening may benefit middle-aged sportsmen, as coronary artery disease (CAD is the main cause of exercise-related sudden cardiac death. Arterial stiffness, as measured by pulse wave velocity (PWV, may help identify sportsmen with subclinical CAD. We examined the additional value of PWV measurements to traditional CAD risk factors for identifying CAD.From the Measuring Athlete's Risk of Cardiovascular events (MARC cohort of asymptomatic, middle-aged sportsmen who underwent low-dose Cardiac CT (CCT after routine sports medical examination (SME, 193 consecutive sportsmen (aged 55 ± 6.6 years were included with additional PWV measurements before CCT. Sensitivity, specificity and predictive values of PWV values (>8.3 and >7.5 m/s assessed by Arteriograph were used to identify CAD (coronary artery calcium scoring ≥ 100 Agatston Units or coronary CT angiography luminal stenosis ≥ 50% and to assess the additional diagnostic value of PWV to established cardiovascular risk factors.Forty-seven sportsmen (24% had CAD on CCT. They were older (58.9 vs. 53.8 years, p8.3m/s respectively >7.5 m/s sensitivity to detect CAD on CT was 43% and 74%, specificity 69% and 45%, positive predictive value 31% and 30%, and negative predictive value 79% and 84%. Adding PWV to traditional risk factor models did not change the area under the curve (from 0.78 (95% CI = 0.709-0.848 to AUC 0.78 (95% CI 0.710-0.848, p = 0.99 for prediction of CAD on CCT.Limited additional value was found for PWV on top of established risk factors to identify CAD. PWV might still have a role to identify CAD in middle-aged sportsmen if risk factors such as cholesterol are unknown.

Pressure waves in a supersaturated bubbly magma

Science.gov (United States)

Kurzon, I.; Lyakhovsky, V.; Navon, O.; Chouet, B.

2011-01-01

We study the interaction of acoustic pressure waves with an expanding bubbly magma. The expansion of magma is the result of bubble growth during or following magma decompression and leads to two competing processes that affect pressure waves. On the one hand, growth in vesicularity leads to increased damping and decreased wave amplitudes, and on the other hand, a decrease in the effective bulk modulus of the bubbly mixture reduces wave velocity, which in turn, reduces damping and may lead to wave amplification. The additional acoustic energy originates from the chemical energy released during bubble growth. We examine this phenomenon analytically to identify conditions under which amplification of pressure waves is possible. These conditions are further examined numerically to shed light on the frequency and phase dependencies in relation to the interaction of waves and growing bubbles. Amplification is possible at low frequencies and when the growth rate of bubbles reaches an optimum value for which the wave velocity decreases sufficiently to overcome the increased damping of the vesicular material. We examine two amplification phase-dependent effects: (1) a tensile-phase effect in which the inserted wave adds to the process of bubble growth, utilizing the energy associated with the gas overpressure in the bubble and therefore converting a large proportion of this energy into additional acoustic energy, and (2) a compressive-phase effect in which the pressure wave works against the growing bubbles and a large amount of its acoustic energy is dissipated during the first cycle, but later enough energy is gained to amplify the second cycle. These two effects provide additional new possible mechanisms for the amplification phase seen in Long-Period (LP) and Very-Long-Period (VLP) seismic signals originating in magma-filled cracks.

A nonlinear model for the fluidization of marine mud by waves

Energy Technology Data Exchange (ETDEWEB)

Foda, M.A.; Hunt, J.R.; Chou, Hsien-Ter (Univ. of California, Berkeley (United States))

1993-04-15

The authors consider the problem of fluidization of mud deposits in shallow waters due to interactions with water waves. This is of increasing interest because of concerns that water pollutants, including heavy metals, pesticides, etc., are often found near surfaces of mud deposits. The authors look at the question of whether the cohesive properties of mud deposits exhibit nonlinear properties when they experience strains from water wave interactions. It is obvious that with large enough wave interactions the deposits become fluidized, and are not in that case truly nonlinear. In their modeling efforts they try to incorporate these ideas into a cohesive model where the magnitude of the water wave-sediment interaction has an influence on the type of response within the system.

Incorporation of Mobile Application (App) Measures Into the Diagnosis of Smartphone Addiction.

Science.gov (United States)

Lin, Yu-Hsuan; Lin, Po-Hsien; Chiang, Chih-Lin; Lee, Yang-Han; Yang, Cheryl C H; Kuo, Terry B J; Lin, Sheng-Hsuan

2017-07-01

Global smartphone expansion has brought about unprecedented addictive behaviors. The current diagnosis of smartphone addiction is based solely on information from clinical interview. This study aimed to incorporate application (app)-recorded data into psychiatric criteria for the diagnosis of smartphone addiction and to examine the predictive ability of the app-recorded data for the diagnosis of smartphone addiction. Smartphone use data of 79 college students were recorded by a newly developed app for 1 month between December 1, 2013, and May 31, 2014. For each participant, psychiatrists made a diagnosis for smartphone addiction based on 2 approaches: (1) only diagnostic interview (standard diagnosis) and (2) both diagnostic interview and app-recorded data (app-incorporated diagnosis). The app-incorporated diagnosis was further used to build app-incorporated diagnostic criteria. In addition, the app-recorded data were pooled as a score to predict smartphone addiction diagnosis. When app-incorporated diagnosis was used as a gold standard for 12 candidate criteria, 7 criteria showed significant accuracy (area under receiver operating characteristic curve [AUC] > 0.7) and were constructed as app-incorporated diagnostic criteria, which demonstrated remarkable accuracy (92.4%) for app-incorporated diagnosis. In addition, both frequency and duration of daily smartphone use significantly predicted app-incorporated diagnosis (AUC = 0.70 for frequency; AUC = 0.72 for duration). The combination of duration, frequency, and frequency trend for 1 month can accurately predict smartphone addiction diagnosis (AUC = 0.79 for app-incorporated diagnosis; AUC = 0.71 for standard diagnosis). The app-incorporated diagnosis, combining both psychiatric interview and app-recorded data, demonstrated substantial accuracy for smartphone addiction diagnosis. In addition, the app-recorded data performed as an accurate screening tool for app-incorporated diagnosis. © Copyright 2017 Physicians

Temporal succession in carbon incorporation from macromolecules by particle-attached bacteria in marine microcosms: Particle-attached bacteria incorporating organic carbon

Energy Technology Data Exchange (ETDEWEB)

Mayali, Xavier [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Stewart, Benjamin [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Mabery, Shalini [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Weber, Peter K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2015-12-21

Here, we investigated bacterial carbon assimilation from stable isotope-labelled macromolecular substrates (proteins; lipids; and two types of polysaccharides, starch and cellobiose) while attached to killed diatom detrital particles during laboratory microcosms incubated for 17 days. Using Chip-SIP (secondary ion mass spectrometry analysis of RNA microarrays), we identified generalist operational taxonomic units (OTUs) from the Gammaproteobacteria, belonging to the genera Colwellia, Glaciecola, Pseudoalteromonas and Rheinheimera, and from the Bacteroidetes, genera Owenweeksia and Maribacter, that incorporated the four tested substrates throughout the incubation period. Many of these OTUs exhibited the highest isotope incorporation relative to the others, indicating that they were likely the most active. Additional OTUs from the Gammaproteobacteria, Bacteroidetes and Alphaproteobacteria exhibited generally (but not always) lower activity and did not incorporate all tested substrates at all times, showing species succession in organic carbon incorporation. We also found evidence to suggest that both generalist and specialist OTUs changed their relative substrate incorporation over time, presumably in response to changing substrate availability as the particles aged. This pattern was demonstrated by temporal succession from relatively higher starch incorporation early in the incubations, eventually switching to higher cellobiose incorporation after 2 weeks.

Signatures of extra dimensions in gravitational waves

Energy Technology Data Exchange (ETDEWEB)

Andriot, David; Gómez, Gustavo Lucena, E-mail: andriotphysics@gmail.com, E-mail: glucenag@aei.mpg.de [Max-Planck-Institut für Gravitationsphysik, Albert-Einstein-Institut, Am Mühlenberg 1, 14467 Potsdam-Golm (Germany)

2017-06-01

Considering gravitational waves propagating on the most general 4+ N -dimensional space-time, we investigate the effects due to the N extra dimensions on the four-dimensional waves. All wave equations are derived in general and discussed. On Minkowski{sub 4} times an arbitrary Ricci-flat compact manifold, we find: a massless wave with an additional polarization, the breathing mode, and extra waves with high frequencies fixed by Kaluza-Klein masses. We discuss whether these two effects could be observed.

Structural Modification in Carbon Nanotubes by Boron Incorporation

Directory of Open Access Journals (Sweden)

Handuja Sangeeta

2009-01-01

Full Text Available Abstract We have synthesized boron-incorporated carbon nanotubes (CNTs by decomposition of ferrocene and xylene in a thermal chemical vapor deposition set up using boric acid as the boron source. Scanning and transmission electron microscopy studies of the synthesized CNT samples showed that there was deterioration in crystallinity and improvement in alignment of the CNTs as the boron content in precursor solution increased from 0% to 15%. Raman analysis of these samples showed a shift of ~7 cm−1in wave number to higher side and broadening of the G band with increasing boron concentration along with an increase in intensity of the G band. Furthermore, there was an increase in the intensity of the D band along with a decrease in its wave number position with increase in boron content. We speculate that these structural modifications in the morphology and microstructure of CNTs might be due to the charge transfer from boron to the graphite matrix, resulting in shortening of the carbon–carbon bonds.

Stable Alfven-wave dynamo action in the reversed-field pinch

International Nuclear Information System (INIS)

Werley, K.A.

1984-01-01

Previous theoretical work has suggested that Alfven waves may be related to the anomalous toroidal magnetic flux generation and extended (over classical expectations) discharge times observed in the reversed-field pinch. This thesis examines the dynamo action of stable Alfven waves as a means of generating toroidal flux. Recent advances in linear resistive MHD stability analysis are used to calculate the quasi-linear dynamo mean electromotive force of Alfven waves. This emf is incorporated into a one-dimensional transport and mean-field evolution code. The changing equilibrium is then fed back to the stability code to complete a computational framework that self-consistently evaluates a dynamic plasma dynamo. This technique is readily extendable to other plasmas in which dynamic stable model action is of interest. Such plasmas include Alfven wave current-drive and plasma heating for fusion devices, as well as astrophysical and geophysical dynamo systems. This study also contains extensive studies of resistive Alfven wave properties. This includes behavior versus spectral location, magnetic Reynolds number and wave number

Shock Wave Speed and Transient Response of PE Pipe with Steel-Mesh Reinforcement

Directory of Open Access Journals (Sweden)

Wuyi Wan

2016-01-01

Full Text Available A steel mesh can improve the tensile strength and stability of a polyethylene (PE pipe in a water supply pipeline system. However, it can also cause more severe water hammer hazard due to increasing wave speed. In order to analyze the influence of the steel mesh on the shock wave speed and transient response processes, an improved wave speed formula is proposed by incorporating the equivalent elastic modulus. A field measurement validates the wave speed formula. Moreover, the transient wave propagation and extreme pressures are simulated and compared by the method of characteristics (MOC for reinforced PE pipes with various steel-mesh densities. Results show that a steel mesh can significantly increase the shock wave speed in a PE pipe and thus can cause severe peak pressure and hydraulic surges in a water supply pipeline system. The proposed wave speed formula can more reasonably evaluate the wave speed and improve the transient simulation of steel-mesh-reinforced PE pipes.

A numerical study on the effects of wave-current-surge interactions on the height and propagation of sea surface waves in Charleston Harbor during Hurricane Hugo 1989

Science.gov (United States)

Liu, Huiqing; Xie, Lian

2009-06-01

The effects of wave-current interactions on ocean surface waves induced by Hurricane Hugo in and around the Charleston Harbor and its adjacent coastal waters are examined by using a three-dimensional (3D) wave-current coupled modeling system. The 3D storm surge modeling component of the coupled system is based on the Princeton Ocean Model (POM), the wave modeling component is based on the third generation wave model, Simulating WAves Nearshore (SWAN), and the inundation model is adopted from [Xie, L., Pietrafesa, L. J., Peng, M., 2004. Incorporation of a mass-conserving inundation scheme into a three-dimensional storm surge model. J. Coastal Res., 20, 1209-1223]. The results indicate that the change of water level associated with the storm surge is the primary cause for wave height changes due to wave-surge interaction. Meanwhile, waves propagating on top of surge cause a feedback effect on the surge height by modulating the surface wind stress and bottom stress. This effect is significant in shallow coastal waters, but relatively small in offshore deep waters. The influence of wave-current interaction on wave propagation is relatively insignificant, since waves generally propagate in the direction of the surface currents driven by winds. Wave-current interactions also affect the surface waves as a result of inundation and drying induced by the storm. Waves break as waters retreat in regions of drying, whereas waves are generated in flooded regions where no waves would have occurred without the flood water.

Drift wave stabilized by an additional streaming ion or plasma population

Science.gov (United States)

Bashir, M. F.; Vranjes, J.

2015-03-01

It is shown that the universally unstable kinetic drift wave in an electron-ion plasma can very effectively be suppressed by adding an extra flowing ion (or plasma) population. The effect of the flow of the added ions is essential, their response is of the type (vp h-vf 0) exp[-(vph-vf 0) 2] , where vf 0 is the flow speed and vp h is the phase speed parallel to the magnetic field vector. The damping is strong and it is mainly due to this ion exponential term, and this remains so for vf 0

Exploration of Wave Development during Yarn Transverse Impact

Directory of Open Access Journals (Sweden)

Matthew Hudspeth

2017-05-01

Full Text Available Single yarns have been impacted in a transverse fashion so as to probe the characteristics of resulting wave development. Longitudinal wave speeds were tracked in efforts to directly measure the yarn tensile stiffness, resulting in a slight increase in the modulus of Kevlar® KM2 and Dyneema® SK76. Additionally, the load developed in AuTx® and Kevlar® KM2 yarns behind the longitudinal wave front has been recorded, providing additional verification for the Smith relations. Further effort to bolster the Smith equations has been successfully performed via tracking transverse wave speeds in AuTx® yarns over a range of impacting velocities. Additional emphasis has been placed at understanding the transverse wave development around the yarn critical velocity, demonstrating that there is a velocity zone where partial yarn failure is detected. Above the critical velocity, measurement of early time transverse wave speeds also agrees with the Smith solution, though the wave speed quickly reduces in value due to the drop in tensile stresses resulting from filament rupture. Finally, the Smith equations have been simplified and are compared to the Cunniff equation, which bear a striking resemblance. Due to such a resemblance, it is suggested that yarn critical velocity experiments can be performed on trial yarn material, and the effect of modifying yarn mechanical properties is discussed.

Spin wave Feynman diagram vertex computation package

Science.gov (United States)

Price, Alexander; Javernick, Philip; Datta, Trinanjan

Spin wave theory is a well-established theoretical technique that can correctly predict the physical behavior of ordered magnetic states. However, computing the effects of an interacting spin wave theory incorporating magnons involve a laborious by hand derivation of Feynman diagram vertices. The process is tedious and time consuming. Hence, to improve productivity and have another means to check the analytical calculations, we have devised a Feynman Diagram Vertex Computation package. In this talk, we will describe our research group's effort to implement a Mathematica based symbolic Feynman diagram vertex computation package that computes spin wave vertices. Utilizing the non-commutative algebra package NCAlgebra as an add-on to Mathematica, symbolic expressions for the Feynman diagram vertices of a Heisenberg quantum antiferromagnet are obtained. Our existing code reproduces the well-known expressions of a nearest neighbor square lattice Heisenberg model. We also discuss the case of a triangular lattice Heisenberg model where non collinear terms contribute to the vertex interactions.

On the Chemical Mixing Induced by Internal Gravity Waves

Energy Technology Data Exchange (ETDEWEB)

Rogers, T. M. [School of Mathematics, Statistics and Physics, Newcastle University, Newcastle upon Tyne (United Kingdom); McElwaine, J. N. [Planetary Science Institute, Tucson, AZ 85721 (United States)

2017-10-10

Detailed modeling of stellar evolution requires a better understanding of the (magneto)hydrodynamic processes that mix chemical elements and transport angular momentum. Understanding these processes is crucial if we are to accurately interpret observations of chemical abundance anomalies, surface rotation measurements, and asteroseismic data. Here, we use two-dimensional hydrodynamic simulations of the generation and propagation of internal gravity waves in an intermediate-mass star to measure the chemical mixing induced by these waves. We show that such mixing can generally be treated as a diffusive process. We then show that the local diffusion coefficient does not depend on the local fluid velocity, but rather on the wave amplitude. We then use these findings to provide a simple parameterization for this diffusion, which can be incorporated into stellar evolution codes and tested against observations.

Current status of musculoskeletal application of shear wave elastography

Energy Technology Data Exchange (ETDEWEB)

Ryu, Jeong Ah [Dept. of Radiology, Hanyang University Guri Hospital, Hanyang University School of Medicine, Guri (Korea, Republic of); Jeong, Woo Kyoung [Dept. of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

2017-07-15

Ultrasonography (US) is a very powerful diagnostic modality for the musculoskeletal system due to the ability to perform real-time dynamic high-resolution examinations with the Doppler technique. In addition to acquiring morphologic data, we can now obtain biomechanical information by quantifying the elasticity of the musculoskeletal structures with US elastography. The earlier diagnosis of degeneration and the ability to perform follow-up evaluations of healing and the effects of treatment are possible. US elastography enables a transition from US-based inspection to US-based palpation in order to diagnose the characteristics of tissue. Shear wave elastography is considered the most suitable type of US elastography for the musculoskeletal system. It is widely used for tendons, ligaments, and muscles. It is important to understand practice guidelines in order to enhance reproducibility. Incorporating viscoelasticity and overcoming inconsistencies among manufacturers are future tasks for improving the capabilities of US elastography.

Current status of musculoskeletal application of shear wave elastography

Directory of Open Access Journals (Sweden)

JeongAh Ryu

2017-07-01

Full Text Available Ultrasonography (US is a very powerful diagnostic modality for the musculoskeletal system due to the ability to perform real-time dynamic high-resolution examinations with the Doppler technique. In addition to acquiring morphologic data, we can now obtain biomechanical information by quantifying the elasticity of the musculoskeletal structures with US elastography. The earlier diagnosis of degeneration and the ability to perform follow-up evaluations of healing and the effects of treatment are possible. US elastography enables a transition from US-based inspection to US-based palpation in order to diagnose the characteristics of tissue. Shear wave elastography is considered the most suitable type of US elastography for the musculoskeletal system. It is widely used for tendons, ligaments, and muscles. It is important to understand practice guidelines in order to enhance reproducibility. Incorporating viscoelasticity and overcoming inconsistencies among manufacturers are future tasks for improving the capabilities of US elastography.

Current status of musculoskeletal application of shear wave elastography

International Nuclear Information System (INIS)

Ryu, Jeong Ah; Jeong, Woo Kyoung

2017-01-01

Ultrasonography (US) is a very powerful diagnostic modality for the musculoskeletal system due to the ability to perform real-time dynamic high-resolution examinations with the Doppler technique. In addition to acquiring morphologic data, we can now obtain biomechanical information by quantifying the elasticity of the musculoskeletal structures with US elastography. The earlier diagnosis of degeneration and the ability to perform follow-up evaluations of healing and the effects of treatment are possible. US elastography enables a transition from US-based inspection to US-based palpation in order to diagnose the characteristics of tissue. Shear wave elastography is considered the most suitable type of US elastography for the musculoskeletal system. It is widely used for tendons, ligaments, and muscles. It is important to understand practice guidelines in order to enhance reproducibility. Incorporating viscoelasticity and overcoming inconsistencies among manufacturers are future tasks for improving the capabilities of US elastography

Simulation study of localization of electromagnetic waves in two-dimensional random dipolar systems

International Nuclear Information System (INIS)

Wang, Ken Kang-Hsin; Ye Zhen

2003-01-01

We study the propagation and scattering of electromagnetic waves by random arrays of dipolar cylinders in a uniform medium. A set of self-consistent equations, incorporating all orders of multiple scattering of the electromagnetic waves, is derived from first principles and then solved numerically for electromagnetic fields. For certain ranges of frequencies, spatially localized electromagnetic waves appear in such a simple but realistic disordered system. Dependence of localization on the frequency, radiation damping, and filling factor is shown. The spatial behavior of the total, coherent, and diffusive waves is explored in detail, and found to comply with a physical intuitive picture. A phase diagram characterizing localization is presented, in agreement with previous investigations on other systems

Simulation study of localization of electromagnetic waves in two-dimensional random dipolar systems.

Science.gov (United States)

Wang, Ken Kang-Hsin; Ye, Zhen

2003-12-01

We study the propagation and scattering of electromagnetic waves by random arrays of dipolar cylinders in a uniform medium. A set of self-consistent equations, incorporating all orders of multiple scattering of the electromagnetic waves, is derived from first principles and then solved numerically for electromagnetic fields. For certain ranges of frequencies, spatially localized electromagnetic waves appear in such a simple but realistic disordered system. Dependence of localization on the frequency, radiation damping, and filling factor is shown. The spatial behavior of the total, coherent, and diffusive waves is explored in detail, and found to comply with a physical intuitive picture. A phase diagram characterizing localization is presented, in agreement with previous investigations on other systems.

Concentrated energy addition for active drag reduction in hypersonic flow regime

Science.gov (United States)

Ashwin Ganesh, M.; John, Bibin

2018-01-01

Numerical optimization of hypersonic drag reduction technique based on concentrated energy addition is presented in this study. A reduction in wave drag is realized through concentrated energy addition in the hypersonic flowfield upstream of the blunt body. For the exhaustive optimization presented in this study, an in-house high precision inviscid flow solver has been developed. Studies focused on the identification of "optimum energy addition location" have revealed the existence of multiple minimum drag points. The wave drag coefficient is observed to drop from 0.85 to 0.45 when 50 Watts of energy is added to an energy bubble of 1 mm radius located at 74.7 mm upstream of the stagnation point. A direct proportionality has been identified between energy bubble size and wave drag coefficient. Dependence of drag coefficient on the upstream added energy magnitude is also revealed. Of the observed multiple minimum drag points, the energy deposition point (EDP) that offers minimum wave drag just after a sharp drop in drag is proposed as the most optimum energy addition location.

Np Incorporation into Uranyl Alteration Phases: A Quantum Mechanical Approach

International Nuclear Information System (INIS)

L.C. Huller; R.C. Win; U.Ecker

2006-01-01

Neptunium is a major contributor to the long-term radioactivity in a geologic repository for spent nuclear fuel (SNF) due to its long half-life (2.1 million years). The mobility of Np may be decreased by incorporation into the U 6+ phases that form during the corrosion of SNF. The ionic radii of Np (0.089nm) and U (0.087nm) are similar, as is their chemistry. Experimental studies have shown Np can be incorporated into uranyl phases at concentrations of ∼ 100 ppm. The low concentration of Np in the uranyl phases complicates experimental detection and presents a significant challenge for determining the incorporation mechanism. Therefore, we have used quantum mechanical calculations to investigate incorporation mechanisms and evaluate the energetics of Np substituting for U. CASTEP, a density functional theory based code that uses plane waves and pseudo-potentials, was used to calculate optimal H positions, relaxed geometry, and energy of different uranyl phases. The incorporation energy for Np in uranyl alteration phases was calculated for studtite, [(UO 2 )O 2 (H 2 O) 2 ](H 2 ) 2 , and boltwoodite, HK(UO 2 )(SiO 4 )* 1.5(H 2 O). Studtite is the rare case of a stable uranyl hydroxyl-peroxide mineral that forms in the presence of H 2 O 2 from the radiolysis of H 2 O. For studtite, two incorporation mechanisms were evaluated: (1) charge-balanced substitution of Np 5+ and H + for one U 6+ , and (2) direct substitution of Np 6+ for U 6+ . For boltwoodite, the H atomic positions prior to Np incorporation were determined, as well as the Np incorporation mechanisms and the corresponding substitution energies. The preferential incorporation of Np into different structure types of U 6+ minerals was also investigated. Quantum mechanical substitution energies have to be derived at Np concentrations higher than the ones found in experiments or expected in a repository. However, the quantum mechanical results are crucial for subsequent empirical force-field and Monte

Estimating the Wet-Rock P-Wave Velocity from the Dry-Rock P-Wave Velocity for Pyroclastic Rocks

Science.gov (United States)

Kahraman, Sair; Fener, Mustafa; Kilic, Cumhur Ozcan

2017-07-01

Seismic methods are widely used for the geotechnical investigations in volcanic areas or for the determination of the engineering properties of pyroclastic rocks in laboratory. Therefore, developing a relation between the wet- and dry-rock P-wave velocities will be helpful for engineers when evaluating the formation characteristics of pyroclastic rocks. To investigate the predictability of the wet-rock P-wave velocity from the dry-rock P-wave velocity for pyroclastic rocks P-wave velocity measurements were conducted on 27 different pyroclastic rocks. In addition, dry-rock S-wave velocity measurements were conducted. The test results were modeled using Gassmann's and Wood's theories and it was seen that estimates for saturated P-wave velocity from the theories fit well measured data. For samples having values of less and greater than 20%, practical equations were derived for reliably estimating wet-rock P-wave velocity as function of dry-rock P-wave velocity.

Analysis of waves in the plasma guided by a periodical vane-type slow wave structure

International Nuclear Information System (INIS)

Wu, T.J.; Kou, C.S.

2005-01-01

In this study, the dispersion relation has been derived to characterize the propagation of the waves in the plasma guided by a periodical vane-type slow wave structure. The plasma is confined by a quartz plate. Results indicate that there are two different waves in this structure. One is the plasma mode that originates from the plasma surface wave propagating along the interface between the plasma and the quartz plate, and the other is the guide mode that originally travels along the vane-type slow wave structure. In contrast to its original slow wave characteristics, the guide mode becomes a fast wave in the low-frequency portion of the passband, and there exists a cut-off frequency for the guide mode. The vane-type guiding structure has been shown to limit the upper frequency of the passband of the plasma mode, compared with that of the plasma surface wave. In addition, the passband of the plasma mode increases with the plasma density while it becomes narrower for the guide mode. The influences of the parameters of the guiding structure and plasma density on the propagation of waves are also presented

Computational study of nonlinear plasma waves. I. Simulation model and monochromatic wave propagtion

International Nuclear Information System (INIS)

Matda, Y.; Crawford, F.W.

1974-12-01

An economical low noise plasma simulation model is applied to a series of problems associated with electrostatic wave propagation in a one-dimensional, collisionless, Maxwellian plasma, in the absence of magnetic field. The model is described and tested, first in the absence of an applied signal, and then with a small amplitude perturbation, to establish the low noise features and to verify the theoretical linear dispersion relation at wave energy levels as low as 0.000,001 of the plasma thermal energy. The method is then used to study propagation of an essentially monochromatic plane wave. Results on amplitude oscillation and nonlinear frequency shift are compared with available theories. The additional phenomena of sideband instability and satellite growth, stimulated by large amplitude wave propagation and the resulting particle trapping, are described. (auth)

3D Modeling of Ultrasonic Wave Interaction with Disbonds and Weak Bonds

Science.gov (United States)

Leckey, C.; Hinders, M.

2011-01-01

Ultrasonic techniques, such as the use of guided waves, can be ideal for finding damage in the plate and pipe-like structures used in aerospace applications. However, the interaction of waves with real flaw types and geometries can lead to experimental signals that are difficult to interpret. 3-dimensional (3D) elastic wave simulations can be a powerful tool in understanding the complicated wave scattering involved in flaw detection and for optimizing experimental techniques. We have developed and implemented parallel 3D elastodynamic finite integration technique (3D EFIT) code to investigate Lamb wave scattering from realistic flaws. This paper discusses simulation results for an aluminum-aluminum diffusion disbond and an aluminum-epoxy disbond and compares results from the disbond case to the common artificial flaw type of a flat-bottom hole. The paper also discusses the potential for extending the 3D EFIT equations to incorporate physics-based weak bond models for simulating wave scattering from weak adhesive bonds.

Anisotropic constitutive equation for use in finite difference wave propagation calculations. [Incorporation into TOODY code

Energy Technology Data Exchange (ETDEWEB)

Swegle, J.W.; Hicks, D.L.

1979-05-01

An anisotropic constitutive relation was incorporated into the Lagrangian finite-difference wavecode TOODY. The details of the implementation of the constitutive relation in the wavecode and an example of its use are discussed. 4 figures, 1 table.

A video Hartmann wavefront diagnostic that incorporates a monolithic microlens array

International Nuclear Information System (INIS)

Toeppen, J.S.; Bliss, E.S.; Long, T.W.; Salmon, J.T.

1991-07-01

we have developed a video Hartmann wavefront sensor that incorporates a monolithic array of microlenses as the focusing elements. The sensor uses a monolithic array of photofabricated lenslets. Combined with a video processor, this system reveals local gradients of the wavefront at a video frame rate of 30 Hz. Higher bandwidth is easily attainable with a camera and video processor that have faster frame rates. When used with a temporal filter, the reconstructed wavefront error is less than 1/10th wave

Self-Powered Wireless Sensor Node Enabled by a Duck-Shaped Triboelectric Nanogenerator for Harvesting Water Wave Energy

KAUST Repository

Ahmed, Abdelsalam

2016-12-08

This paper presents a fully enclosed duck-shaped triboelectric nanogenerator (TENG) for effectively scavenging energy from random and low-frequency water waves. The design of the TENG incorporates the freestanding rolling mode and the pitch motion of a duck-shaped structure generated by incident waves. By investigating the material and structural features, a unit of the TENG device is successfully designed. Furthermore, a hybrid system is constructed using three units of the TENG device. The hybrid system achieves an instantaneous peak current of 65.5 µA with an instantaneous output power density of up to 1.366 W m−2. Following the design, a fluid–solid interaction analysis is carried out on one duck-shaped TENG to understand the dynamic behavior, mechanical efficiency, and stability of the device under various water wave conditions. In addition, the hybrid system is experimentally tested to enable a commercial wireless temperature sensor node. In summary, the unique duck-shaped TENG shows a simple, cost-effective, environmentally friendly, light-weight, and highly stable system. The newly designed TENG is promising for building a network of generators to harvest existing blue energy in oceans, lakes, and rivers.

Self-Powered Wireless Sensor Node Enabled by a Duck-Shaped Triboelectric Nanogenerator for Harvesting Water Wave Energy

KAUST Repository

Ahmed, Abdelsalam; Saadatnia, Zia; Hassan, Islam; Zi, Yunlong; Xi, Yi; He, Xu; Zu, Jean; Wang, Zhong Lin

2016-01-01

This paper presents a fully enclosed duck-shaped triboelectric nanogenerator (TENG) for effectively scavenging energy from random and low-frequency water waves. The design of the TENG incorporates the freestanding rolling mode and the pitch motion of a duck-shaped structure generated by incident waves. By investigating the material and structural features, a unit of the TENG device is successfully designed. Furthermore, a hybrid system is constructed using three units of the TENG device. The hybrid system achieves an instantaneous peak current of 65.5 µA with an instantaneous output power density of up to 1.366 W m−2. Following the design, a fluid–solid interaction analysis is carried out on one duck-shaped TENG to understand the dynamic behavior, mechanical efficiency, and stability of the device under various water wave conditions. In addition, the hybrid system is experimentally tested to enable a commercial wireless temperature sensor node. In summary, the unique duck-shaped TENG shows a simple, cost-effective, environmentally friendly, light-weight, and highly stable system. The newly designed TENG is promising for building a network of generators to harvest existing blue energy in oceans, lakes, and rivers.

Fundamental formulae for wave-energy conversion.

Science.gov (United States)

Falnes, Johannes; Kurniawan, Adi

2015-03-01

The time-average wave power that is absorbed from an incident wave by means of a wave-energy conversion (WEC) unit, or by an array of WEC units-i.e. oscillating immersed bodies and/or oscillating water columns (OWCs)-may be mathematically expressed in terms of the WEC units' complex oscillation amplitudes, or in terms of the generated outgoing (diffracted plus radiated) waves, or alternatively, in terms of the radiated waves alone. Following recent controversy, the corresponding three optional expressions are derived, compared and discussed in this paper. They all provide the correct time-average absorbed power. However, only the first-mentioned expression is applicable to quantify the instantaneous absorbed wave power and the associated reactive power. In this connection, new formulae are derived that relate the 'added-mass' matrix, as well as a couple of additional reactive radiation-parameter matrices, to the difference between kinetic energy and potential energy in the water surrounding the immersed oscillating WEC array. Further, a complex collective oscillation amplitude is introduced, which makes it possible to derive, by a very simple algebraic method, various simple expressions for the maximum time-average wave power that may be absorbed by the WEC array. The real-valued time-average absorbed power is illustrated as an axisymmetric paraboloid defined on the complex collective-amplitude plane. This is a simple illustration of the so-called 'fundamental theorem for wave power'. Finally, the paper also presents a new derivation that extends a recently published result on the direction-average maximum absorbed wave power to cases where the WEC array's radiation damping matrix may be singular and where the WEC array may contain OWCs in addition to oscillating bodies.

Stable Alfven wave dynamo action in the reversed field pinch

International Nuclear Information System (INIS)

Werley, K.A.

1984-01-01

Recent advances in linear resistive MHD stability analysis are used to calculate the quasi-linear dynamo mean electromotive force of Alfven waves. This emf is incorporated into a one-dimensional transport and mean-field evolution code. The changing equilibrium is then fed back to the stability code to complete a computational framework that self-consistently evaluates a dynamic plasma dynamo. Static quasi-linear Alfven wave calculations have shown that dynamo emfs on the order of eta vector J are possible. This suggested a possible explanation of RFP behavior and a new (externally driven) mechanism for extending operation and controlling field profiles (possibly reducing plasma transport). This thesis demonstrates that the dynamo emf can quickly induce plasma currents whose emf cancels the dynamo effect. This thesis also contains extensive studies of resistive Alfven wave properties. This includes behavior versus spectral location, magnetic Reynolds number and wave number

Charge density waves in solids

CERN Document Server

Gor'kov, LP

2012-01-01

The latest addition to this series covers a field which is commonly referred to as charge density wave dynamics.The most thoroughly investigated materials are inorganic linear chain compounds with highly anisotropic electronic properties. The volume opens with an examination of their structural properties and the essential features which allow charge density waves to develop.The behaviour of the charge density waves, where interesting phenomena are observed, is treated both from a theoretical and an experimental standpoint. The role of impurities in statics and dynamics is considered and an

A Novel 3D Viscoelastic Acoustic Wave Equation Based Update Method for Reservoir History Matching

KAUST Repository

Katterbauer, Klemens

2014-12-10

The oil and gas industry has been revolutionized within the last decade, with horizontal drilling and hydraulic fracturing enabling the extraction of huge amounts of shale gas in areas previously considered impossible and the recovering of hydrocarbons in harsh environments like the arctic or in previously unimaginable depths like the off-shore exploration in the South China sea and Gulf of Mexico. With the development of 4D seismic, engineers and scientists have been enabled to map the evolution of fluid fronts within the reservoir and determine the displacement caused by the injected fluids. This in turn has led to enhanced production strategies, cost reduction and increased profits. Conventional approaches to incorporate seismic data into the history matching process have been to invert these data for constraints that are subsequently employed in the history matching process. This approach makes the incorporation computationally expensive and requires a lot of manual processing for obtaining the correct interpretation due to the potential artifacts that are generated by the generally ill-conditioned inversion problems. I have presented here a novel approach via including the time-lapse cross-well seismic survey data directly into the history matching process. The generated time-lapse seismic data are obtained from the full wave 3D viscoelastic acoustic wave equation. Furthermore an extensive analysis has been performed showing the robustness of the method and enhanced forecastability of the critical reservoir parameters, reducing uncertainties and exhibiting the benefits of a full wave 3D seismic approach. Finally, the improved performance has been statistically confirmed. The improvements illustrate the significant improvements in forecasting that are obtained via readily available seismic data without the need for inversion. This further optimizes oil production in addition to increasing return-on-investment on oil & gas field development projects, especially

Addition of electric arc furnace dust in hot metal changing the form of addition

International Nuclear Information System (INIS)

Marques Sobrinho, Vicente de Paulo Ferreira; Oliveira, Jose Roberto de; Vieira, Estefano Aparecido; Telles, Victor Bridi; Grillo, Felipe Fardin; Tenorio, Jorge Alberto Soares; Espinosa, Denise Crocce Romano

2014-01-01

This research aims to study the incorporation of the mass of electric arc furnace dust (EAFD), by addition in hot metal (1.78% Si) at a temperature of 1,400 degrees Celsius. The EAFD is from a steel plant producing long steel. The addition of the EAFD was as received, in the form of briquettes without agitation of the hot metal and in the form of briquettes with agitation of the hot metal. Previously, the EAFD was characterized using the following techniques: chemical analysis, size analysis, X-ray diffraction, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) microanalysis. The achievement of fusion experiments in laboratory scale, took place in a vertical tubular furnace with temperature control. The fusion experiments to assess the incorporation of EAFD mass used graphite crucibles. After cooling, the hot metal and the slag, remaining in the crucible, were weighed to do a mass balance. A flow of inert gas (argon) was maintained inside the furnace during the experiments. Results show that the experiment with addition of EAFD as received presents the best result of incorporating the mass of the final hot metal (1.73%) combined with the lowest percentage of volatilized mass of EAFD (46.52%). The experiment addition of EAFD in the form of briquette with agitation of hot metal presents the lowest percentage of slag mass (4.58%). The zinc content of volatilized EAFD (64.30%) is higher than the zinc content of the imported ore concentrate (52%) and zinc content of the national ore concentrate (12% to 39%). The presence of lead and cadmium in the slag characterizing it as a hazardous solid waste. (author)

Surf similarity and solitary wave runup

DEFF Research Database (Denmark)

Fuhrman, David R.; Madsen, Per A.

2008-01-01

The notion of surf similarity in the runup of solitary waves is revisited. We show that the surf similarity parameter for solitary waves may be effectively reduced to the beach slope divided by the offshore wave height to depth ratio. This clarifies its physical interpretation relative to a previ...... functional dependence on their respective surf similarity parameters. Important equivalencies in the runup of sinusoidal and solitary waves are thus revealed.......The notion of surf similarity in the runup of solitary waves is revisited. We show that the surf similarity parameter for solitary waves may be effectively reduced to the beach slope divided by the offshore wave height to depth ratio. This clarifies its physical interpretation relative...... to a previous parameterization, which was not given in an explicit form. Good coherency with experimental (breaking) runup data is preserved with this simpler parameter. A recasting of analytical (nonbreaking) runup expressions for sinusoidal and solitary waves additionally shows that they contain identical...

Travelling Waves in Hybrid Chemotaxis Models

KAUST Repository

Franz, Benjamin

2013-12-18

Hybrid models of chemotaxis combine agent-based models of cells with partial differential equation models of extracellular chemical signals. In this paper, travelling wave properties of hybrid models of bacterial chemotaxis are investigated. Bacteria are modelled using an agent-based (individual-based) approach with internal dynamics describing signal transduction. In addition to the chemotactic behaviour of the bacteria, the individual-based model also includes cell proliferation and death. Cells consume the extracellular nutrient field (chemoattractant), which is modelled using a partial differential equation. Mesoscopic and macroscopic equations representing the behaviour of the hybrid model are derived and the existence of travelling wave solutions for these models is established. It is shown that cell proliferation is necessary for the existence of non-transient (stationary) travelling waves in hybrid models. Additionally, a numerical comparison between the wave speeds of the continuum models and the hybrid models shows good agreement in the case of weak chemotaxis and qualitative agreement for the strong chemotaxis case. In the case of slow cell adaptation, we detect oscillating behaviour of the wave, which cannot be explained by mean-field approximations. © 2013 Society for Mathematical Biology.

Qualitative and quantitative characterization of plasma proteins when incorporating traveling wave ion mobility into a liquid chromatography-mass spectrometry workflow for biomarker discovery: use of product ion quantitation as an alternative data analysis tool for label free quantitation.

Science.gov (United States)

Daly, Charlotte E; Ng, Leong L; Hakimi, Amirmansoor; Willingale, Richard; Jones, Donald J L

2014-02-18

Discovery of protein biomarkers in clinical samples necessitates significant prefractionation prior to liquid chromatography-mass spectrometry (LC-MS) analysis. Integrating traveling wave ion mobility spectrometry (TWIMS) enables in-line gas phase separation which when coupled with nanoflow liquid chromatography and data independent acquisition tandem mass spectrometry, confers significant advantages to the discovery of protein biomarkers by improving separation and inherent sensitivity. Incorporation of TWIMS leads to a packet of concentrated ions which ultimately provides a significant improvement in sensitivity. As a consequence of ion packeting, when present at high concentrations, accurate quantitation of proteins can be affected due to detector saturation effects. Human plasma was analyzed in triplicate using liquid-chromatography data independent acquisition mass spectrometry (LC-DIA-MS) and using liquid-chromatography ion-mobility data independent acquisition mass spectrometry (LC-IM-DIA-MS). The inclusion of TWIMS was assessed for the effect on sample throughput, data integrity, confidence of protein and peptide identification, and dynamic range. The number of identified proteins is significantly increased by an average of 84% while both the precursor and product mass accuracies are maintained between the modalities. Sample dynamic range is also maintained while quantitation is achieved for all but the most abundant proteins by incorporating a novel data interpretation method that allows accurate quantitation to occur. This additional separation is all achieved within a workflow with no discernible deleterious effect on throughput. Consequently, TWIMS greatly enhances proteome coverage and can be reliably used for quantification when using an alternative product ion quantification strategy. Using TWIMS in biomarker discovery in human plasma is thus recommended.

Holographic s-wave and p-wave Josephson junction with backreaction

Energy Technology Data Exchange (ETDEWEB)

Wang, Yong-Qiang; Liu, Shuai [Institute of Theoretical Physics, Lanzhou University,Lanzhou 730000, People’s Republic of (China)

2016-11-22

In this paper, we study the holographic models of s-wave and p-wave Josephoson junction away from probe limit in (3+1)-dimensional spacetime, respectively. With the backreaction of the matter, we obtained the anisotropic black hole solution with the condensation of matter fields. We observe that the critical temperature of Josephoson junction decreases with increasing backreaction. In addition to this, the tunneling current and condenstion of Josephoson junction become smaller as backreaction grows larger, but the relationship between current and phase difference still holds for sine function. Moreover, condenstion of Josephoson junction deceases with increasing width of junction exponentially.

Nonlinear theory of localized standing waves

OpenAIRE

Denardo, Bruce; Larraza, Andrés; Putterman, Seth; Roberts, Paul

1992-01-01

An investigation of the nonlinear dispersive equations of continuum mechanics reveals localized standing-wave solutions that are domain walls between regions of different wave number. These states can appear even when the dispersion law is a single-valued function of the wave number. In addition, we calculate solutions for kinks in cutoff and noncutoff modes, as well as cutoff breather solitons. Division of Engineering and Geophysics of the Office of Basic Energy Science of U.S. DOE for su...

Test particle method for incorporation of the kinetic effects into the envelope simulations of Raman backscattering

International Nuclear Information System (INIS)

Hur, Min Sup; Suk, Hyyong

2007-01-01

A new test particle method is presented for self-consistent incorporation of the kinetic effects into the fluid three-wave model. One of the most important kinetic effects is the electron trapping and it has been found that the trapping affects significantly the behavior of Raman backscatter and Raman backward laser amplification. The conventional fluid three-wave model cannot reproduce the kinetic simulations in the trapping regime. The test particle scheme utilizes the same equations for the laser evolution as in the three-wave model. However, the plasma wave is treated by the envelope-kinetic equation, which consists of envelope evolution and the kinetic term. The core of the new scheme is employing test particles to compute the kinetic term self-consistently. The benchmarking results against the averaged particle-in-cell (aPIC) code show excellent agreements, and the computation speed gain over the aPIC is from 2 to 20 depending on parameters

An Analysis of the Impact of Heat Waves in Labor and Crop Productivity in the Agricultural Sector in California

Science.gov (United States)

Castillo, F.; Wehner, M. F.; Gilless, J. K.

2017-12-01

California agriculture is an important economic activity for the state. California leads the nation in farms sales since 1950. In addition, agricultural employment in California reached approximately 410,000. Production of many fruits and vegetables is labor intensive and labor costs represent anywhere from 20% to 40% of total production costs. In additon, agricutlural production growth has been the highest for labor intensive crops such as berries (all types) and nuts. Given the importance of the agricultural sector and the labor component whithin it, the analysis of the impact of climate change on the agricultural sector of California becomes imperative. Heat waves are a weather related extreme that impact labor productivity, specially outdoor labor producitivity. We use crop production function analysis that incorporates socio economic variables such as crop prices, total acreage, production levels and harvest timiline with climate related variables such as an estimated Heat Index (HI) to analize the impact of heat waves on crop production via an impact on labor productivity for selected crops in the Central and Imperial Valleys in California. The analysis finds that the impact of heat waves varies by the degree of labor intensity of the crop and the relative intensity of the heat wave.

Fear Extinction Memory Consolidation Requires Potentiation of Pontine-Wave Activity during REM Sleep

Science.gov (United States)

Datta, Subimal; O'Malley, Matthew W .

2013-01-01

Sleep plays an important role in memory consolidation within multiple memory systems including contextual fear extinction memory, but little is known about the mechanisms that underlie this process. Here, we show that fear extinction training in rats, which extinguished conditioned fear, increased both slow-wave sleep and rapid-eye movement (REM) sleep. Surprisingly, 24 h later, during memory testing, only 57% of the fear-extinguished animals retained fear extinction memory. We found that these animals exhibited an increase in phasic pontine-wave (P-wave) activity during post-training REM sleep, which was absent in the 43% of animals that failed to retain fear extinction memory. The results of this study provide evidence that brainstem activation, specifically potentiation of phasic P-wave activity, during post-training REM sleep is critical for consolidation of fear extinction memory. The results of this study also suggest that, contrary to the popular hypothesis of sleep and memory, increased sleep after training alone does not guarantee consolidation and/or retention of fear extinction memory. Rather, the potentiation of specific sleep-dependent physiological events may be a more accurate predictor for successful consolidation of fear extinction memory. Identification of this unique mechanism will significantly improve our present understanding of the cellular and molecular mechanisms that underlie the sleep-dependent regulation of emotional memory. Additionally, this discovery may also initiate development of a new, more targeted treatment method for clinical disorders of fear and anxiety in humans that is more efficacious than existing methods such as exposure therapy that incorporate only fear extinction. PMID:23467372

Low-cost wave characterization modules for oil spill response

Directory of Open Access Journals (Sweden)

E.D. Skinner

2018-06-01

Full Text Available Marine oil spills can be remediated by mechanical skimmers in calm waters, but performance degrades with increased wave height. We have developed and demonstrated a system that quantifies local wave characteristics with an uncertainty of four inches of heave. Our system is intended for the measurement of wave characteristics during oil spill recovery. It conveys this information to coordinators and responders in real time via WiFi and remote reporting through a satellite network. This information will allow for enhanced situational awareness during an oil spill response, assisting stakeholders and optimizing mechanical skimming operations. Our wave characterization module (WCM uses accelerometer outputs from a very small inertial measurement unit (IMU to generate wave statistics and calculate wave characteristics. It is configured such that a WCM can either be attached to a skimmer float or incorporated into a microbuoy. Wave height and period are transmitted via WiFi and/or a satellite-enabled mesh-grid network to a cloud-hosted geographic information system (GIS. Here, we discuss the bare-bones sensors-plus-algorithm approach we developed by using spring-mass systems to approximate the wave height and period regime of interest. We then describe open water tests carried out using that development system both mounted to a weir skimmer mockup and packaged in a microbuoy. Finally, we present controlled tests in the wave tank at Ohmsett, the National Oil Spill Response Test Facility in New Jersey, with the WCMs communicating the wave characteristics via WiFi to tankside laptops and via satellite to the cloud-based GIS. Snapshot determinations of wave height calculated using the scalar magnitude of the three-axis accelerometer in the IMU were within four inches of the benchmark wave measurement system at Ohmsett. Keywords: Oil spill, Wave characterization module, Inertial measurement unit, Microbuoy

Travelling wave solutions for the Richards equation incorporating non-equilibrium effects in the capillarity pressure

NARCIS (Netherlands)

van Duijn, C. J.; Mitra, K.; Pop, I. S.

2018-01-01

The Richards equation is a mathematical model for unsaturated flow through porous media. This paper considers an extension of the Richards equation, where non-equilibrium effects like hysteresis and dynamic capillarity are incorporated in the relationship that relates the water pressure and the

Making waves in a photoactive polymer film

Science.gov (United States)

Gelebart, Anne Helene; Jan Mulder, Dirk; Varga, Michael; Konya, Andrew; Vantomme, Ghislaine; Meijer, E. W.; Selinger, Robin L. B.; Broer, Dirk J.

2017-06-01

Oscillating materials that adapt their shapes in response to external stimuli are of interest for emerging applications in medicine and robotics. For example, liquid-crystal networks can be programmed to undergo stimulus-induced deformations in various geometries, including in response to light. Azobenzene molecules are often incorporated into liquid-crystal polymer films to make them photoresponsive; however, in most cases only the bending responses of these films have been studied, and relaxation after photo-isomerization is rather slow. Modifying the core or adding substituents to the azobenzene moiety can lead to marked changes in photophysical and photochemical properties, providing an opportunity to circumvent the use of a complex set-up that involves multiple light sources, lenses or mirrors. Here, by incorporating azobenzene derivatives with fast cis-to-trans thermal relaxation into liquid-crystal networks, we generate photoactive polymer films that exhibit continuous, directional, macroscopic mechanical waves under constant light illumination, with a feedback loop that is driven by self-shadowing. We explain the mechanism of wave generation using a theoretical model and numerical simulations, which show good qualitative agreement with our experiments. We also demonstrate the potential application of our photoactive films in light-driven locomotion and self-cleaning surfaces, and anticipate further applications in fields such as photomechanical energy harvesting and miniaturized transport.

Shear Alfvén Wave with Quantum Exchange-Correlation Effects in Plasmas

Science.gov (United States)

Mir, Zahid; Jamil, M.; Rasheed, A.; Asif, M.

2017-09-01

The dust shear Alfvén wave is studied in three species dusty quantum plasmas. The quantum effects are incorporated through the Fermi degenerate pressure, tunneling potential, and in particular the exchange-correlation potential. The significance of exchange-correlation potential is pointed out by a graphical description of the dispersion relation, which shows that the exchange potential magnifies the phase speed. The low-frequency shear Alfvén wave is studied while considering many variables. The shear Alfvén wave gains higher phase speed at the range of small angles for the upper end of the wave vector spectrum. The increasing dust charge and the external magnetic field reflect the increasing tendency of phase speed. This study may explain many natural mechanisms associated with long wavelength radiations given in the summary.

Phase velocity of nonlinear plasma waves in the laser beat-wave accelerator

International Nuclear Information System (INIS)

Spence, W.L.

1985-01-01

The suggested plasma-laser accelerator is an attempt to achieve a very high energy gradient by resonantly exciting a longitudinal wave traveling at close to the speed of light in cold plasma by means of the beat-wave generated by the transverse fields in two laser beams. Previous calculations to all orders in v/sub z/ have been done essentially from the laboratory frame point of view and have treated the plasma wave as having sharply defined phase velocity equal to the speed of light. However a high energy particle beam undergoing acceleration sees the plasma wave from a nearly light-like frame of reference and hence is very sensitive to small deviations in its phase velocity. Here the authors introduce a calculational scheme that includes all orders in v/sub z/ and in the plasma density, and additionally takes into account the influence of plasma nonlinearities on the wave's phase velocity. The main assumption is that the laser frequencies are very large compared to the plasma frequency - under which they are able to in essence formally sum up all orders of forward Raman scattering. They find that the nonlinear plasma wave does not have simply a single phase velocity - it is really a superposition of many - but that the beat-wave which drives it is usefully described by a non-local effective phase velocity function

Plasma wave and second harmonic generation

International Nuclear Information System (INIS)

Sodha, M.S.; Sharma, J.K.; Tewari, D.P.; Sharma, R.P.; Kaushik, S.C.

1978-01-01

An investigation is made of a plasma wave at pump wave frequency and second harmonic generation caused by a self induced transverse inhomogeneity introduced by a Gaussian electromagnetic beam in a hot collisionless plasma. In the presence of a Gaussian beam the carriers get redistributed from the high field region to the low field region by ponderomative force and a transverse density gradient is established in the plasma. When the electric vector of the main beam is parallel to this density gradient, a plasma wave at the pump wave frequency is generated. In addition to this the transverse intensity gradient of the electromagnetic wave also contributes significantly to the plasma wave generation. The power of the plasma wave exhibits a maximum and minimum with the power of the pump wave (at z = 0). The generated plasma wave interacts with the electromagnetic wave and leads to the generation of a second harmonic. Furthermore, if the initial power of the pump wave is more than the critical power for self-focusing, the beam gets self-focused and hence the generated plasma wave and second harmonic which depend upon the background electron concentration and power of the main beam also get accordingly modified. (author)

Near-field photon wave mechanics in the Lorenz gauge

International Nuclear Information System (INIS)

Keller, Ole

2007-01-01

Optical near-field interactions are studied theoretically in the perspective of photon wave mechanics paying particular attention to the dynamics in the wave-vector time domain. A unitary transformation is used to replace the scalar and longitudinal photon variables by so-called near-field and gauge photon variables. Dynamical equations are established for these types of photon variables, and it is shown that these equations are invariant against gauge transformations within the Lorenz gauge. The near-field photon is absent in the free-field limit, and the gauge photon can be eliminated by a suitable gauge transformation. Implicit solutions for the near-field, gauge, and transverse photon variables are obtained and discussed. The general theory is applied to an investigation of transverse photon propagation in a uniform solid-state plasma dominated by the diamagnetic field-matter interaction. It is found that the diamagnetic response can be incorporated in a quantum mechanical wave equation for a massive transverse photon. The Compton wave number of the massive photon equals the plasma wave number of the electron system. A dynamical equation describing the emission of a massive transverse photon from a mesoscopic source embedded in the plasma is finally established

Fine structure and analytical quantum-defect wave functions

International Nuclear Information System (INIS)

Kostelecky, V.A.; Nieto, M.M.; Truax, D.R.

1988-01-01

We investigate the domain of validity of previously proposed analytical wave functions for atomic quantum-defect theory. This is done by considering the fine-structure splitting of alkali-metal and singly ionized alkaline-earth atoms. The Lande formula is found to be naturally incorporated. A supersymmetric-type integer is necessary for finite results. Calculated splittings correctly reproduce the principal features of experimental values for alkali-like atoms

An anisotropic shear velocity model of the Earth's mantle using normal modes, body waves, surface waves and long-period waveforms

Science.gov (United States)

Moulik, P.; Ekström, G.

2014-12-01

We use normal-mode splitting functions in addition to surface wave phase anomalies, body wave traveltimes and long-period waveforms to construct a 3-D model of anisotropic shear wave velocity in the Earth's mantle. Our modelling approach inverts for mantle velocity and anisotropy as well as transition-zone discontinuity topographies, and incorporates new crustal corrections for the splitting functions that are consistent with the non-linear corrections we employ for the waveforms. Our preferred anisotropic model, S362ANI+M, is an update to the earlier model S362ANI, which did not include normal-mode splitting functions in its derivation. The new model has stronger isotropic velocity anomalies in the transition zone and slightly smaller anomalies in the lowermost mantle, as compared with S362ANI. The differences in the mid- to lowermost mantle are primarily restricted to features in the Southern Hemisphere. We compare the isotropic part of S362ANI+M with other recent global tomographic models and show that the level of agreement is higher now than in the earlier generation of models, especially in the transition zone and the lower mantle. The anisotropic part of S362ANI+M is restricted to the upper 300 km in the mantle and is similar to S362ANI. When radial anisotropy is allowed throughout the mantle, large-scale anisotropic patterns are observed in the lowermost mantle with vSV > vSH beneath Africa and South Pacific and vSH > vSV beneath several circum-Pacific regions. The transition zone exhibits localized anisotropic anomalies of ˜3 per cent vSH > vSV beneath North America and the Northwest Pacific and ˜2 per cent vSV > vSH beneath South America. However, small improvements in fits to the data on adding anisotropy at depth leave the question open on whether large-scale radial anisotropy is required in the transition zone and in the lower mantle. We demonstrate the potential of mode-splitting data in reducing the trade-offs between isotropic velocity and

A perspective on multiple waves of influenza pandemics.

Science.gov (United States)

Mummert, Anna; Weiss, Howard; Long, Li-Ping; Amigó, José M; Wan, Xiu-Feng

2013-01-01

A striking characteristic of the past four influenza pandemic outbreaks in the United States has been the multiple waves of infections. However, the mechanisms responsible for the multiple waves of influenza or other acute infectious diseases are uncertain. Understanding these mechanisms could provide knowledge for health authorities to develop and implement prevention and control strategies. We exhibit five distinct mechanisms, each of which can generate two waves of infections for an acute infectious disease. The first two mechanisms capture changes in virus transmissibility and behavioral changes. The third mechanism involves population heterogeneity (e.g., demography, geography), where each wave spreads through one sub-population. The fourth mechanism is virus mutation which causes delayed susceptibility of individuals. The fifth mechanism is waning immunity. Each mechanism is incorporated into separate mathematical models, and outbreaks are then simulated. We use the models to examine the effects of the initial number of infected individuals (e.g., border control at the beginning of the outbreak) and the timing of and amount of available vaccinations. Four models, individually or in any combination, reproduce the two waves of the 2009 H1N1 pandemic in the United States, both qualitatively and quantitatively. One model reproduces the two waves only qualitatively. All models indicate that significantly reducing or delaying the initial numbers of infected individuals would have little impact on the attack rate. Instead, this reduction or delay results in a single wave as opposed to two waves. Furthermore, four of these models also indicate that a vaccination program started earlier than October 2009 (when the H1N1 vaccine was initially distributed) could have eliminated the second wave of infection, while more vaccine available starting in October would not have eliminated the second wave.

A perspective on multiple waves of influenza pandemics.

Directory of Open Access Journals (Sweden)

Anna Mummert

Full Text Available A striking characteristic of the past four influenza pandemic outbreaks in the United States has been the multiple waves of infections. However, the mechanisms responsible for the multiple waves of influenza or other acute infectious diseases are uncertain. Understanding these mechanisms could provide knowledge for health authorities to develop and implement prevention and control strategies.We exhibit five distinct mechanisms, each of which can generate two waves of infections for an acute infectious disease. The first two mechanisms capture changes in virus transmissibility and behavioral changes. The third mechanism involves population heterogeneity (e.g., demography, geography, where each wave spreads through one sub-population. The fourth mechanism is virus mutation which causes delayed susceptibility of individuals. The fifth mechanism is waning immunity. Each mechanism is incorporated into separate mathematical models, and outbreaks are then simulated. We use the models to examine the effects of the initial number of infected individuals (e.g., border control at the beginning of the outbreak and the timing of and amount of available vaccinations.Four models, individually or in any combination, reproduce the two waves of the 2009 H1N1 pandemic in the United States, both qualitatively and quantitatively. One model reproduces the two waves only qualitatively. All models indicate that significantly reducing or delaying the initial numbers of infected individuals would have little impact on the attack rate. Instead, this reduction or delay results in a single wave as opposed to two waves. Furthermore, four of these models also indicate that a vaccination program started earlier than October 2009 (when the H1N1 vaccine was initially distributed could have eliminated the second wave of infection, while more vaccine available starting in October would not have eliminated the second wave.

Fundamentals and Applications of Ultrasonic Waves

CERN Document Server

Cheeke, J David N

2012-01-01

Designed specifically for newcomers to the field, this fully updated second edition begins with fundamentals and quickly advances beyond general wave concepts into an in-depth treatment of ultrasonic waves in isotropic media. Focusing on the physics of acoustic waves, their propagation, technology, and applications, this accessible overview of ultrasonics includes accounts of viscoelasticity and multiple scattering. It examines new technologies, including atomic force acoustic microscopy, lasers, micro-acoustics, and nanotechnology. In addition, it highlights both direct and indirect applicati

WindWaveFloat (WWF): Final Scientific Report

Energy Technology Data Exchange (ETDEWEB)

Weinstein, Alla; Roddier, Dominique; Banister, Kevin

2012-03-30

Principle Power Inc. and National Renewable Energy Lab (NREL) have completed a contract to assess the technical and economic feasibility of integrating wave energy converters into the WindFloat, resulting in a new concept called the WindWaveFloat (WWF). The concentration of several devices on one platform could offer a potential for both economic and operational advantages. Wind and wave energy converters can share the electrical cable and power transfer equipment to transport the electricity to shore. Access to multiple generation devices could be simplified, resulting in cost saving at the operational level. Overall capital costs may also be reduced, provided that the design of the foundation can be adapted to multiple devices with minimum modifications. Finally, the WindWaveFloat confers the ability to increase energy production from individual floating support structures, potentially leading to a reduction in levelized energy costs, an increase in the overall capacity factor, and greater stability of the electrical power delivered to the grid. The research conducted under this grant investigated the integration of several wave energy device types into the WindFloat platform. Several of the resulting system designs demonstrated technical feasibility, but the size and design constraints of the wave energy converters (technical and economic) make the WindWaveFloat concept economically unfeasible at this time. Not enough additional generation could be produced to make the additional expense associated with wave energy conversion integration into the WindFloat worthwhile.

The two-wave X-ray field calculated by means of integral-equation methods

International Nuclear Information System (INIS)

Bremer, J.

1984-01-01

The problem of calculating the two-wave X-ray field on the basis of the Takagi-Taupin equations is discussed for the general case of curved lattice planes. A two-dimensional integral equation which incorporates the nature of the incoming radiation, the form of the crystal/vacuum boundary, and the curvature of the structure, is deduced. Analytical solutions for the symmetrical Laue case with incoming plane waves are obtained directly for perfect crystals by means of iteration. The same method permits a simple derivation of the narrow-wave Laue and Bragg cases. Modulated wave fronts are discussed, and it is shown that a cut-off in the width of an incoming plane wave leads to lateral oscillations which are superimposed on the Pendelloesung fringes. Bragg and Laue shadow fields are obtained. The influence of a non-zero kernel is discussed and a numerical procedure for calculating wave amplitudes in curved crystals is presented. (Auth.)

On a class of nonlocal wave equations from applications

Science.gov (United States)

Beyer, Horst Reinhard; Aksoylu, Burak; Celiker, Fatih

2016-06-01

We study equations from the area of peridynamics, which is a nonlocal extension of elasticity. The governing equations form a system of nonlocal wave equations. We take a novel approach by applying operator theory methods in a systematic way. On the unbounded domain ℝn, we present three main results. As main result 1, we find that the governing operator is a bounded function of the governing operator of classical elasticity. As main result 2, a consequence of main result 1, we prove that the peridynamic solutions strongly converge to the classical solutions by utilizing, for the first time, strong resolvent convergence. In addition, main result 1 allows us to incorporate local boundary conditions, in particular, into peridynamics. This avenue of research is developed in companion papers, providing a remedy for boundary effects. As main result 3, employing spherical Bessel functions, we give a new practical series representation of the solution which allows straightforward numerical treatment with symbolic computation.

STEREO OBSERVATIONS OF FAST MAGNETOSONIC WAVES IN THE EXTENDED SOLAR CORONA ASSOCIATED WITH EIT/EUV WAVES

International Nuclear Information System (INIS)

Kwon, Ryun-Young; Ofman, Leon; Kramar, Maxim; Olmedo, Oscar; Davila, Joseph M.; Thompson, Barbara J.; Cho, Kyung-Suk

2013-01-01

We report white-light observations of a fast magnetosonic wave associated with a coronal mass ejection observed by STEREO/SECCHI/COR1 inner coronagraphs on 2011 August 4. The wave front is observed in the form of density compression passing through various coronal regions such as quiet/active corona, coronal holes, and streamers. Together with measured electron densities determined with STEREO COR1 and Extreme UltraViolet Imager (EUVI) data, we use our kinematic measurements of the wave front to calculate coronal magnetic fields and find that the measured speeds are consistent with characteristic fast magnetosonic speeds in the corona. In addition, the wave front turns out to be the upper coronal counterpart of the EIT wave observed by STEREO EUVI traveling against the solar coronal disk; moreover, stationary fronts of the EIT wave are found to be located at the footpoints of deflected streamers and boundaries of coronal holes, after the wave front in the upper solar corona passes through open magnetic field lines in the streamers. Our findings suggest that the observed EIT wave should be in fact a fast magnetosonic shock/wave traveling in the inhomogeneous solar corona, as part of the fast magnetosonic wave propagating in the extended solar corona.

Optical bulk and surface waves with negative refraction

International Nuclear Information System (INIS)

Agranovich, V.M.; Shen, Y.R.; Baughman, R.H.; Zakhidov, A.A.

2004-01-01

In materials with negative refraction, the direction of wave propagation is opposite to the direction of the wave vector. Using an approach that characterizes the optical response of a medium totally by a generalized dielectric permittivity, ε-bar (ω,k-bar), we discuss the possibility of seeing negative refraction for optical waves in a number of nonmagnetic media. These include bulk waves in organic materials and in gyrotropic materials where additional exciton-polariton waves can have a negative group velocity. It is known that dispersion of surface waves can be engineered by tailoring a surface transition layer. We show how this effect can be used to obtain surface waves with negative refraction

Real-Time Detection of Rupture Development: Earthquake Early Warning Using P Waves From Growing Ruptures

Science.gov (United States)

Kodera, Yuki

2018-01-01

Large earthquakes with long rupture durations emit P wave energy throughout the rupture period. Incorporating late-onset P waves into earthquake early warning (EEW) algorithms could contribute to robust predictions of strong ground motion. Here I describe a technique to detect in real time P waves from growing ruptures to improve the timeliness of an EEW algorithm based on seismic wavefield estimation. The proposed P wave detector, which employs a simple polarization analysis, successfully detected P waves from strong motion generation areas of the 2011 Mw 9.0 Tohoku-oki earthquake rupture. An analysis using 23 large (M ≥ 7) events from Japan confirmed that seismic intensity predictions based on the P wave detector significantly increased lead times without appreciably decreasing the prediction accuracy. P waves from growing ruptures, being one of the fastest carriers of information on ongoing rupture development, have the potential to improve the performance of EEW systems.

Path integral for spinning particle in the plane wave field: Global and local projections

International Nuclear Information System (INIS)

Boudiaf, N.; Boudjedaa, T.; Chetouani, L.

2001-01-01

The Green function related to the problem of a Dirac particle interacting with a plane wave is calculated via the path integral formalism proposed recently by Alexandrou et al. according to the two so-called global and local projections. With the help of the incorporation of two simple identities, it is shown that the contribution to the calculation of the integrals comes essentially from classical solutions projected along the direction of wave propagation. (orig.)

Two-wave propagation in in vitro swine distal ulna

Science.gov (United States)

Mano, Isao; Horii, Kaoru; Matsukawa, Mami; Otani, Takahiko

2015-07-01

Ultrasonic transmitted waves were obtained in an in vitro swine distal ulna specimen, which mimics a human distal radius, that consists of interconnected cortical bone and cancellous bone. The transmitted waveforms appeared similar to the fast waves, slow waves, and overlapping fast and slow waves measured in the specimen after removing the surface cortical bone (only cancellous bone). In addition, the circumferential waves in the cortical bone and water did not affect the fast and slow waves. This suggests that the fast-and-slow-wave phenomenon can be observed in an in vivo human distal radius.

The impact of heat waves on children's health: a systematic review

Science.gov (United States)

Xu, Zhiwei; Sheffield, Perry E.; Su, Hong; Wang, Xiaoyu; Bi, Yan; Tong, Shilu

2014-03-01

Young children are thought to be particularly sensitive to heat waves, but relatively less research attention has been paid to this field to date. A systematic review was conducted to elucidate the relationship between heat waves and children's health. Literature published up to August 2012 were identified using the following MeSH terms and keywords: "heatwave", "heat wave", "child health", "morbidity", "hospital admission", "emergency department visit", "family practice", "primary health care", "death" and "mortality". Of the 628 publications identified, 12 met the selection criteria. The existing literature does not consistently suggest that mortality among children increases significantly during heat waves, even though infants were associated with more heat-related deaths. Exposure to heat waves in the perinatal period may pose a threat to children's health. Pediatric diseases or conditions associated with heat waves include renal disease, respiratory disease, electrolyte imbalance and fever. Future research should focus on how to develop a consistent definition of a heat wave from a children's health perspective, identifying the best measure of children's exposure to heat waves, exploring sensitive outcome measures to quantify the impact of heat waves on children, evaluating the possible impacts of heat waves on children's birth outcomes, and understanding the differences in vulnerability to heat waves among children of different ages and from different income countries. Projection of the children's disease burden caused by heat waves under climate change scenarios, and development of effective heat wave mitigation and adaptation strategies that incorporate other child protective health measures, are also strongly recommended.

Symmetrized partial-wave method for density-functional cluster calculations

International Nuclear Information System (INIS)

Averill, F.W.; Painter, G.S.

1994-01-01

The computational advantage and accuracy of the Harris method is linked to the simplicity and adequacy of the reference-density model. In an earlier paper, we investigated one way the Harris functional could be extended to systems outside the limits of weakly interacting atoms by making the charge density of the interacting atoms self-consistent within the constraints of overlapping spherical atomic densities. In the present study, a method is presented for augmenting the interacting atom charge densities with symmetrized partial-wave expansions on each atomic site. The added variational freedom of the partial waves leads to a scheme capable of giving exact results within a given exchange-correlation approximation while maintaining many of the desirable convergence and stability properties of the original Harris method. Incorporation of the symmetry of the cluster in the partial-wave construction further reduces the level of computational effort. This partial-wave cluster method is illustrated by its application to the dimer C 2 , the hypothetical atomic cluster Fe 6 Al 8 , and the benzene molecule

Studying Lorentz-violating electromagnetic waves in confined media

International Nuclear Information System (INIS)

Viana, Davidson R.; Gomes, Andre H.; Fonseca, Jakson M.; Moura-Melo, Winder A.

2009-01-01

Full text. Planck energy scale is still far beyond current possibilities. A question of interest is whether the Lorentz symmetry remains valid at these extremely high energies, whose answer certainly would be useful whenever building grand unified theories, in which general relativity is consistently accommodated. Here, we study a reminiscent of this possible symmetry violation, incorporated in the body of the so-called Standard Model Extension (SME). More precisely, we deal with the pure (Abelian) gauge sector, so that we have a modified classical electromagnetism in (3+1) dimensions, whose Lagrangian include a term proportional to a (constant) background tensor that breaks the Lorentz symmetry, but respecting CPT. Our attention is devoted to the wave-like solutions constrained to propagate inside confined media, like waveguides and resonant cavities. Our preliminary findings indicate that Lorentz-breaking implies in modifications of the standard results which are proportional to the (very small) violating parameters, but could be largely enhanced by diminishing the size of the confined media. Under study is the case of a toroidal cavity where the electromagnetic field should respect the additional requirement of being single-valued in the (toroidal) angular variable. Perhaps, such an extra feature combined with the usual boundary conditions could lead us to large effects of this violation, somewhat similar to those predicted for CPT- and Lorentz-odd electromagnetic waves constrained to propagate along a hollow conductor waveguide. (author)

Advanced computational simulations of water waves interacting with wave energy converters

Science.gov (United States)

Pathak, Ashish; Freniere, Cole; Raessi, Mehdi

2017-03-01

Wave energy converter (WEC) devices harness the renewable ocean wave energy and convert it into useful forms of energy, e.g. mechanical or electrical. This paper presents an advanced 3D computational framework to study the interaction between water waves and WEC devices. The computational tool solves the full Navier-Stokes equations and considers all important effects impacting the device performance. To enable large-scale simulations in fast turnaround times, the computational solver was developed in an MPI parallel framework. A fast multigrid preconditioned solver is introduced to solve the computationally expensive pressure Poisson equation. The computational solver was applied to two surface-piercing WEC geometries: bottom-hinged cylinder and flap. Their numerically simulated response was validated against experimental data. Additional simulations were conducted to investigate the applicability of Froude scaling in predicting full-scale WEC response from the model experiments.

Lagrangian modelling of ocean surface waves and synthetic aperture radar wave measurements

Energy Technology Data Exchange (ETDEWEB)

Fouques, Sebastien

2005-07-01

, along with a RAR modulation transfer function (MTF) with a larger amplitude. Eventually, an optimization of the RAR MTF is carried out by making use of the co-located database and the dependency of the optimized parameters on the wind velocity is studied. In the last three articles. Lagrangian models for ocean surface waves are investigated, and the main results are the following. In Article III, ocean surface properties such as the slope and the curvature are studied for linear irregular waves, and the difference between the Eulerian and the Lagrangian wave spectra is illustrated. In addition, some features of the second-order Lagrangian solution for irregular long-crested waves are presented. Then, in Article IV, the Lagrangian equations of motion, as given in Lamb (1932), are extended to include the irrotational flow assumption and simplified by eliminating the pressure. The first-order solution for two-dimensional irregular waves given by Pierson (1961) is modified through a change of variables that makes the mass conservation equation be fulfilled exactly, instead of being correct to the first order only. The resulting waves show higher sharp crests than in Pierson's solution, in which some water locally and temporary disappears in the vicinity of the surface. Furthermore, a three-dimensional second-order irrotational solution is derived. Monte Carlo simulations of irregular long-crested waves reveal that the fronts of some waves may steepen, while the fluid located on their back side and near the surface is hurled forward, in a way similar to an early stage breaking wave. Then, it is demonstrated that at the second order, short-crested waves develop curved crests owing to a non-uniform current field. Finally, the ability of the Lagrangian formalism to describe capillary waves is investigated in Article V. Assuming that surface tension is the only restoring force, the profile of the first-order monochromatic solution is the same as for gravity waves, with

Geometrical Determinants of Neuronal Actin Waves.

Science.gov (United States)

Tomba, Caterina; Braïni, Céline; Bugnicourt, Ghislain; Cohen, Floriane; Friedrich, Benjamin M; Gov, Nir S; Villard, Catherine

2017-01-01

Hippocampal neurons produce in their early stages of growth propagative, actin-rich dynamical structures called actin waves. The directional motion of actin waves from the soma to the tip of neuronal extensions has been associated with net forward growth, and ultimately with the specification of neurites into axon and dendrites. Here, geometrical cues are used to control actin wave dynamics by constraining neurons on adhesive stripes of various widths. A key observable, the average time between the production of consecutive actin waves, or mean inter-wave interval (IWI), was identified. It scales with the neurite width, and more precisely with the width of the proximal segment close to the soma. In addition, the IWI is independent of the total number of neurites. These two results suggest a mechanistic model of actin wave production, by which the material conveyed by actin waves is assembled in the soma until it reaches the threshold leading to the initiation and propagation of a new actin wave. Based on these observations, we formulate a predictive theoretical description of actin wave-driven neuronal growth and polarization, which consistently accounts for different sets of experiments.

An adaptive Bayesian inversion for upper mantle structure using surface waves and scattered body waves

Science.gov (United States)

Eilon, Zachary; Fischer, Karen M.; Dalton, Colleen A.

2018-04-01

We present a methodology for 1-D imaging of upper mantle structure using a Bayesian approach that incorporates a novel combination of seismic data types and an adaptive parameterisation based on piecewise discontinuous splines. Our inversion algorithm lays the groundwork for improved seismic velocity models of the lithosphere and asthenosphere by harnessing the recent expansion of large seismic arrays and computational power alongside sophisticated data analysis. Careful processing of P- and S-wave arrivals isolates converted phases generated at velocity gradients between the mid-crust and 300 km depth. This data is allied with ambient noise and earthquake Rayleigh wave phase velocities to obtain detailed VS and VP velocity models. Synthetic tests demonstrate that converted phases are necessary to accurately constrain velocity gradients, and S-p phases are particularly important for resolving mantle structure, while surface waves are necessary for capturing absolute velocities. We apply the method to several stations in the northwest and north-central United States, finding that the imaged structure improves upon existing models by sharpening the vertical resolution of absolute velocity profiles, offering robust uncertainty estimates, and revealing mid-lithospheric velocity gradients indicative of thermochemical cratonic layering. This flexible method holds promise for increasingly detailed understanding of the upper mantle.

Wave-induced nearshore circulation along the Calangute-Candolim beach, Goa, West coast of India

Digital Repository Service at National Institute of Oceanography (India)

Krishnakumar, V.; Murty, C.S.; Heblekar, A.K.

The wave-induced nearshore circulation model suggested by Noda has been modified and applied for three small segments along the coast of Goa. The present model incorporates the prevailing bottom topography and considers its variation along...

Periodontal tissue regeneration with PRP incorporated gelatin hydrogel sponges

International Nuclear Information System (INIS)

Nakajima, Dai; Tabata, Yasuhiko; Sato, Soh

2015-01-01

Gelatin hydrogels have been designed and prepared for the controlled release of the transforming growth factor (TGF-b1) and the platelet-derived growth factor (PDGF-BB). PRP (Platelet rich plasma) contains many growth factors including the PDGF and TGF-b1. The objective of this study was to evaluate the regeneration of periodontal tissue following the controlled release of growth factors in PRP. For the periodontal ligament cells and osteoblast, PRP of different concentrations was added. The assessment of DNA, mitochondrial activity and ALP activity were measured. To evaluate the TGF-β1 release from PRP incorporated gelatin sponge, amounts of TGF-β1 in each supernatant sample were determined by the ELISA. Transplantation experiments to prepare a bone defect in a rat alveolar bone were an implanted gelatin sponge incorporated with different concentration PRP. In DNA assay and MTT assay, after the addition of PRP to the periodontal ligament cells and osteoblast, the cell count and mitochondrial activity had increased the most in the group with the addition of 5  ×  PRP. In the ALP assay, after the addition of PRP to the periodontal ligament cells, the cell activity had increased the most in the group with the addition of 3  ×  PRP. In the transplantation, the size of the bone regenerated in the defect with 3  ×  PRP incorporated gelatin sponge was larger than that of the other group. (paper)

Periodontal tissue regeneration with PRP incorporated gelatin hydrogel sponges.

Science.gov (United States)

Nakajima, Dai; Tabata, Yasuhiko; Sato, Soh

2015-10-20

Gelatin hydrogels have been designed and prepared for the controlled release of the transforming growth factor (TGF-b1) and the platelet-derived growth factor (PDGF-BB). PRP (Platelet rich plasma) contains many growth factors including the PDGF and TGF-b1. The objective of this study was to evaluate the regeneration of periodontal tissue following the controlled release of growth factors in PRP. For the periodontal ligament cells and osteoblast, PRP of different concentrations was added. The assessment of DNA, mitochondrial activity and ALP activity were measured. To evaluate the TGF-β1 release from PRP incorporated gelatin sponge, amounts of TGF-β1 in each supernatant sample were determined by the ELISA. Transplantation experiments to prepare a bone defect in a rat alveolar bone were an implanted gelatin sponge incorporated with different concentration PRP. In DNA assay and MTT assay, after the addition of PRP to the periodontal ligament cells and osteoblast, the cell count and mitochondrial activity had increased the most in the group with the addition of 5  ×  PRP. In the ALP assay, after the addition of PRP to the periodontal ligament cells, the cell activity had increased the most in the group with the addition of 3  ×  PRP. In the transplantation, the size of the bone regenerated in the defect with 3  ×  PRP incorporated gelatin sponge was larger than that of the other group.

Reliability Study of Energy Harvesting from Sea Waves by Piezoelectric Patches Consideraing Random JONSWAP Wave Theory

Directory of Open Access Journals (Sweden)

M. Ettefagh

2018-03-01

Full Text Available One of the new methods for powering low-power electronic devices employed in the sea, is using of mechanical energies of sea waves. In this method, piezoelectric material is employed to convert the mechanical energy of sea waves into electrical energy. The advantage of this method is based on not implementing the battery charging system. Although, many studies have been done about energy harvesting from sea waves, energy harvesting with considering random JONWSAP wave theory is not fully studied up to now. The random JONSWAP wave model is a more realistic approximation of sea waves in comparison of Airy wave model. Therefore, in this paper a vertical beam with the piezoelectric patches, which is fixed to the seabed, is considered as energy harvester system. The energy harvesting system is simulated by MATLAB software, and then the vibration response of the beam and consequently the generated power is obtained considering the JONWSAP wave theory. In addition, the reliability of the system and the effect of piezoelectric patches uncertainties on the generated power are studied by statistical method. Furthermore, the failure possibility of harvester based on violation criteria is investigated.  

Several localized waves induced by linear interference between a nonlinear plane wave and bright solitons

Science.gov (United States)

Qin, Yan-Hong; Zhao, Li-Chen; Yang, Zhan-Ying; Yang, Wen-Li

2018-01-01

We investigate linear interference effects between a nonlinear plane wave and bright solitons, which are admitted by a pair-transition coupled two-component Bose-Einstein condensate. We demonstrate that the interference effects can induce several localized waves possessing distinctive wave structures, mainly including anti-dark solitons, W-shaped solitons, multi-peak solitons, Kuznetsov-Ma like breathers, and multi-peak breathers. Specifically, the explicit conditions for them are clarified by a phase diagram based on the linear interference properties. Furthermore, the interactions between these localized waves are discussed. The detailed analysis indicates that the soliton-soliton interaction induced phase shift brings the collision between these localized waves which can be inelastic for solitons involving collision and can be elastic for breathers. These characters come from the fact that the profile of solitons depends on the relative phase between bright solitons and a plane wave, and the profile of breathers does not depend on the relative phase. These results would motivate more discussions on linear interference between other nonlinear waves. Specifically, the solitons or breathers obtained here are not related to modulational instability. The underlying reasons are discussed in detail. In addition, possibilities to observe these localized waves are discussed in a two species Bose-Einstein condensate.

Dynamic wave field synthesis: enabling the generation of field distributions with a large space-bandwidth product.

Science.gov (United States)

Kamau, Edwin N; Heine, Julian; Falldorf, Claas; Bergmann, Ralf B

2015-11-02

We present a novel approach for the design and fabrication of multiplexed computer generated volume holograms (CGVH) which allow for a dynamic synthesis of arbitrary wave field distributions. To achieve this goal, we developed a hybrid system that consists of a CGVH as a static element and an electronically addressed spatial light modulator as the dynamic element. We thereby derived a new model for describing the scattering process within the inhomogeneous dielectric material of the hologram. This model is based on the linearization of the scattering process within the Rytov approximation and incorporates physical constraints that account for voxel based laser-lithography using micro-fabrication of the holograms in a nonlinear optical material. In this article we demonstrate that this system basically facilitates a high angular Bragg selectivity on the order of 1°. Additionally, it allows for a qualitatively low cross-talk dynamic synthesis of predefined wave fields with a much larger space-bandwidth product (SBWP ≥ 8.7 × 10(6)) as compared to the current state of the art in computer generated holography.

Numerical study on non-locally reacting behavior of nacelle liners incorporating drainage slots

Science.gov (United States)

Chen, Chao; Li, Xiaodong; Thiele, Frank

2018-06-01

For acoustic liners used in current commercial nacelles, in order to prevent any liquid accumulating in the resonators, drainage slots are incorporated on the partition walls between closely packed cavities. Recently, an experimental study conducted by Busse-Gerstengarbe et al. shown that the cell interaction introduced by drainage slots causes an additional dissipation peak which increases with the size of the slot. However, the variation of damping process due to drainage slots is still not fully understood. Therefore, a numerical study based on computational aeroacoustic methods is carried out to investigate the mechanism of the changed attenuation characteristics due to drainage slots in presence of grazing incident sound waves with low or high intensities. Different slot configurations are designed based on the generic non-locally reacting liner model adopted in the experimental investigation. Both 2-D and 3-D numerical simulations of only slit resonators are carried out. Numerical results indicate that the extra peak is a result of a resonance excited in the second cavity at specific frequency. Under high sound pressure level incoming waves, the basic characteristics of the acoustic performance remain. However, vortex shedding transpires at the resonances around both the slits and the drainage slot. Vorticity contours show that the connection of two coupled cavities decreases the strength of vortex shedding around the basic Helmholtz resonance due to a higher energy reflection. Meanwhile, the cell interaction significantly increases the vorticity magnitude near the extra resonant frequency. Finally, a semi-empirical model is derived to predict the extra attenuation peak frequency.

Influence of incorporated bromodeoxyuridine on the induction of chromosomal alterations by ionizing radiation and long-wave UV in CHO cells.

Science.gov (United States)

Zwanenburg, T S; van Zeeland, A A; Natarajan, A T

1985-01-01

Incorporation of BrdUrd into nuclear DNA sensitizes CHO cells (1) to the induction of chromosomal aberrations by X-rays and 0.5 MeV neutrons and (2) to induction of chromosomal aberrations and SCEs by lw-UV. We have attempted to establish a correlation between induced chromosomal alterations and induced single- or double-strand breaks in DNA. The data show that while DSBs correlate very well with X-ray-induced aberrations, no clear correlation could be established between lw-UV induced SSBs (including alkali-labile sites) and chromosomal alterations. In addition the effect of 3-aminobenzamide (3AB) on the induction of chromosomal aberrations and SCEs induced by lw-UV has been determined. It is shown that 3AB is without any effect when lw-UV-irradiated cells are posttreated with this inhibitor. The significance of these results is discussed.

Wave-Kinetic Simulations of the Nonlinear Generation of Electromagnetic VLF Waves through Velocity Ring Instabilities

Science.gov (United States)

Ganguli, G.; Crabtree, C. E.; Rudakov, L.; Mithaiwala, M.

2014-12-01

Velocity ring instabilities are a common naturally occuring magnetospheric phenomenon that can also be generated by man made ionospheric experiments. These instabilities are known to generate lower-hybrid waves, which generally cannot propagte out of the source region. However, nonlinear wave physics can convert these linearly driven electrostatic lower-hybrid waves into electromagnetic waves that can escape the source region. These nonlinearly generated waves can be an important source of VLF turbulence that controls the trapped electron lifetime in the radiation belts. We develop numerical solutions to the wave-kinetic equation in a periodic box including the effects of nonlinear (NL) scattering (nonlinear Landau damping) of Lower-hybrid waves giving the evolution of the wave-spectra in wavenumber space. Simultaneously we solve the particle diffusion equation of both the background plasma particles and the ring ions, due to both linear and nonlinear Landau resonances. At initial times for cold ring ions, an electrostatic beam mode is excited, while the kinetic mode is stable. As the instability progresses the ring ions heat, the beam mode is stabilized, and the kinetic mode destabilizes. When the amplitude of the waves becomes sufficient the lower-hybrid waves are scattered (by either nearly unmagnetized ions or magnetized electrons) into electromagnetic magnetosonic waves [Ganguli et al 2010]. The effect of NL scattering is to limit the amplitude of the waves, slowing down the quasilinear relaxation time and ultimately allowing more energy from the ring to be liberated into waves [Mithaiwala et al. 2011]. The effects of convection out of the instability region are modeled, additionally limiting the amplitude of the waves, allowing further energy to be liberated from the ring [Scales et al., 2012]. Results are compared to recent 3D PIC simulations [Winske and Duaghton 2012].

Magnetohydrodynamic spin waves in degenerate electron-positron-ion plasmas

Energy Technology Data Exchange (ETDEWEB)

Mushtaq, A. [TPPD, PINSTECH Nilore, 44000 Islamabad (Pakistan); National Center for Physics, Shahdrah Valley Road, 44000 Islamabad (Pakistan); Maroof, R.; Ahmad, Zulfiaqr [Institute of Physics and Electronics, University of Peshawar, 25000 Peshawar (Pakistan); Qamar, A. [National Center for Physics, Shahdrah Valley Road, 44000 Islamabad (Pakistan); Institute of Physics and Electronics, University of Peshawar, 25000 Peshawar (Pakistan)

2012-05-15

Low frequency magnetosonic waves are studied in magnetized degenerate electron-positron-ion plasmas with spin effects. Using the fluid equations of magnetoplasma with quantum corrections due to the Bohm potential, temperature degeneracy, and spin magnetization energy, a generalized dispersion relation for oblique magnetosonic waves is derived. Spin effects are incorporated via spin force and macroscopic spin magnetization current. For three different values of angle {theta}, the generalized dispersion relation is reduced to three different relations under the low frequency magnetohydrodynamic assumptions. It is found that the effect of quantum corrections in the presence of positron concentration significantly modifies the dispersive properties of these modes. The importance of the work relevant to compact astrophysical bodies is pointed out.

Rac1 regulates neuronal polarization through the WAVE complex

DEFF Research Database (Denmark)

Tahirovic, Sabina; Hellal, Farida; Neukirchen, Dorothee

2010-01-01

the physiological function of Rac1 in neuronal development, we have generated a conditional knock-out mouse, in which Rac1 is ablated in the whole brain. Rac1-deficient cerebellar granule neurons, which do not express other Rac isoforms, showed impaired neuronal migration and axon formation both in vivo...... and in vitro. In addition, Rac1 ablation disrupts lamellipodia formation in growth cones. The analysis of Rac1 effectors revealed the absence of the Wiskott-Aldrich syndrome protein (WASP) family verprolin-homologous protein (WAVE) complex from the plasma membrane of knock-out growth cones. Loss of WAVE...... function inhibited axon growth, whereas overexpression of a membrane-tethered WAVE mutant partially rescued axon growth in Rac1-knock-out neurons. In addition, pharmacological inhibition of the WAVE complex effector Arp2/3 also reduced axon growth. We propose that Rac1 recruits the WAVE complex...

Extension of NHWAVE to Couple LAMMPS for Modeling Wave Interactions with Arctic Ice Floes

Science.gov (United States)

2015-09-30

Modelling, in press. Orzech, M., Shi, F., Veeramony, J., Bateman , S., Calantoni, J., and Kirby, J. T., 2015, “Incorporating floating surface...objects into a fully dispersive surface wave model”, Ocean Modelling, submitted. Bateman , S. Shi, F., Orzech, M., Veeramony, J., and Calantoni, J., 2014...Orzech, M., Shi, F., Calantoni, J., Bateman , S., and Veeramony, J., “Small-scale modeling of waves and floes in the Marginal Ice Zone”, 2014 Fall Meeting of the American Geophysical Union.

Power counting of various Dirac covariants in hadronic Bethe–Salpeter wave functions for pseudoscalar meson decays

International Nuclear Information System (INIS)

Bhatnagar, S.; Li, Shiyuan; Mahecha, J.

2011-01-01

We have employed the framework of Bethe–Salpeter equation under covariant instantaneous ansatz to calculate leptonic decay constants of unequal mass pseudoscalar mesons like π ± , K, D, D S and B, and radiative decay constants of neutral pseudoscalar mesons like π 0 and η c into two photons. In the Dirac structure of hadronic Bethe–Salpeter wave function, the covariants are incorporated from their complete set in accordance with a recently proposed power counting rule. The contribution of both leading order and next-to-leading order Dirac covariants to decay constants are studied. The results are found to improve and hence validating the power counting rule which provides a practical means of incorporating Dirac covariants in the Bethe–Salpeter wave function for a hadron. (author)

Direct Drive Wave Energy Buoy

Energy Technology Data Exchange (ETDEWEB)

Rhinefrank, Kenneth E. [Columbia Power Technologies, Inc.; Lenee-Bluhm, Pukha [Columbia Power Technologies, Inc.; Prudell, Joseph H. [Columbia Power Technologies, Inc.; Schacher, Alphonse A. [Columbia Power Technologies, Inc.; Hammagren, Erik J. [Columbia Power Technologies, Inc.; Zhang, Zhe [Columbia Power Technologies, Inc.

2013-07-29

The most prudent path to a full-scale design, build and deployment of a wave energy conversion (WEC) system involves establishment of validated numerical models using physical experiments in a methodical scaling program. This Project provides essential additional rounds of wave tank testing at 1:33 scale and ocean/bay testing at a 1:7 scale, necessary to validate numerical modeling that is essential to a utility-scale WEC design and associated certification.

Additional heating experiments of FRC plasmas

International Nuclear Information System (INIS)

Okada, S.; Asai, T.; Kodera, F.; Kitano, K.; Suzuki, T.; Yamanaka, K.; Kanki, T.; Inomoto, M.; Yoshimura, S.; Okubo, M.; Sugimoto, S.; Ohi, S.; Goto, S.

2001-01-01

Additional heating experiments of neutral beam (NB) injection and application of low frequency wave on a plasma with extremely high averaged beta value of about 90% - a field reversed configuration (FRC) plasma - are carried out on the FRC Injection experiment (FIX) apparatus. These experiments are made possible by translating the FRC plasma produced in a formation region of a theta pinch to a confinement region in order to secure better accessibility to heating facilities and to control plasma density. By appropriate choice of injection geometry and the mirror ratio of the confinement region, the NB with the energy of 14keV and the current of 23A is enabled to be injected into the FRC in the solenoidal confining field of only 0.04-0.05T. Confinement is improved by this experiment. Ion heating is observed by the application of low frequency (80kHz ; about 1/4 of the ion gyro frequency) compressional wave. A shear wave, probably mode converted from the compressional wave, is detected to propagate axially. (author)

An attempt to estimate isotropic and anisotropic lateral structure of the Earth by spectral inversion incorporating mixed coupling

Science.gov (United States)

Oda, Hitoshi

2005-02-01

We present a way to calculate free oscillation spectra for an aspherical earth model, which is constructed by adding isotropic and anisotropic velocity perturbations to the seismic velocity parameters of a reference earth model, and examine the effect of the velocity perturbations on the free oscillation spectrum. Lateral variations of the velocity perturbations are parametrized as an expansion in generalized spherical harmonics. We assume weak hexagonal anisotropy for the seismic wave anisotropy in the upper mantle, where the hexagonal symmetry axes are horizontally distributed. The synthetic spectra show that the velocity perturbations cause not only strong self-coupling among singlets of a multiplet but also mixed coupling between toroidal and spheroidal multiplets. Both the couplings give rise to an amplitude anomaly on the vertical component spectrum. In this study, we identify the amplitude anomaly resulting from the mixed coupling as quasi-toroidal mode. Excitation of the quasi-toroidal mode by a vertical strike-slip fault is largest on nodal lines of the Rayleigh wave, decreases with increasing azimuth angle and becomes smallest on loop lines. This azimuthal dependence of the spectral amplitude is quite similar to the Love wave radiation pattern. In addition, the amplitude spectrum of the quasi-toroidal mode is more sensitive to the anisotropic velocity perturbation than to the isotropic velocity perturbation. This means that the mode spectrum allowing for the mixed-coupling effect may provide constraints on the anisotropic lateral structure as well as the isotropic lateral structure. An inversion method, called mixed-coupling spectral inversion, is devised to retrieve the isotropic and anisotropic velocity perturbations from the free oscillation spectra incorporating the quasi-toroidal mode. We confirm that the spectral inversion method correctly recovers the isotropic and anisotropic lateral structure. Moreover introducing the mixed-coupling effect in the

Traveling-wave laser-produced-plasma energy source for photoionization laser pumping and lasers incorporating said

Science.gov (United States)

Sher, Mark H.; Macklin, John J.; Harris, Stephen E.

1989-09-26

A traveling-wave, laser-produced-plasma, energy source used to obtain single-pass gain saturation of a photoionization pumped laser. A cylindrical lens is used to focus a pump laser beam to a long line on a target. Grooves are cut in the target to present a surface near normal to the incident beam and to reduce the area, and hence increase the intensity and efficiency, of plasma formation.

Analysis of Different Methods for Wave Generation and Absorption in a CFD-Based Numerical Wave Tank

Directory of Open Access Journals (Sweden)

Adria Moreno Miquel

2018-06-01

Full Text Available In this paper, the performance of different wave generation and absorption methods in computational fluid dynamics (CFD-based numerical wave tanks (NWTs is analyzed. The open-source CFD code REEF3D is used, which solves the Reynolds-averaged Navier–Stokes (RANS equations to simulate two-phase flow problems. The water surface is computed with the level set method (LSM, and turbulence is modeled with the k-ω model. The NWT includes different methods to generate and absorb waves: the relaxation method, the Dirichlet-type method and active wave absorption. A sensitivity analysis has been conducted in order to quantify and compare the differences in terms of absorption quality between these methods. A reflection analysis based on an arbitrary number of wave gauges has been adopted to conduct the study. Tests include reflection analysis of linear, second- and fifth-order Stokes waves, solitary waves, cnoidal waves and irregular waves generated in an NWT. Wave breaking over a sloping bed and wave forces on a vertical cylinder are calculated, and the influence of the reflections on the wave breaking location and the wave forces on the cylinder is investigated. In addition, a comparison with another open-source CFD code, OpenFOAM, has been carried out based on published results. Some differences in the calculated quantities depending on the wave generation and absorption method have been observed. The active wave absorption method is seen to be more efficient for long waves, whereas the relaxation method performs better for shorter waves. The relaxation method-based numerical beach generally results in lower reflected waves in the wave tank for most of the cases simulated in this study. The comparably better performance of the relaxation method comes at the cost of larger computational requirements due to the relaxation zones that have to be included in the domain. The reflections in the NWT in REEF3D are generally lower than the published results for

Updated thermal model using simplified short-wave radiosity calculations

International Nuclear Information System (INIS)

Smith, J.A.; Goltz, S.M.

1994-01-01

An extension to a forest canopy thermal radiance model is described that computes the short-wave energy flux absorbed within the canopy by solving simplified radiosity equations describing flux transfers between canopy ensemble classes partitioned by vegetation layer and leaf slope. Integrated short-wave reflectance and transmittance-factors obtained from measured leaf optical properties were found to be nearly equal for the canopy studied. Short-wave view factor matrices were approximated by combining the average leaf scattering coefficient with the long-wave view factor matrices already incorporated in the model. Both the updated and original models were evaluated for a dense spruce fir forest study site in Central Maine. Canopy short-wave absorption coefficients estimated from detailed Monte Carlo ray tracing calculations were 0.60, 0.04, and 0.03 for the top, middle, and lower canopy layers corresponding to leaf area indices of 4.0, 1.05, and 0.25. The simplified radiosity technique yielded analogous absorption values of 0.55, 0.03, and 0.01. The resulting root mean square error in modeled versus measured canopy temperatures for all layers was less than 1°C with either technique. Maximum error in predicted temperature using the simplified radiosity technique was approximately 2°C during peak solar heating. (author)

Updated thermal model using simplified short-wave radiosity calculations

Energy Technology Data Exchange (ETDEWEB)

Smith, J. A.; Goltz, S. M.

1994-02-15

An extension to a forest canopy thermal radiance model is described that computes the short-wave energy flux absorbed within the canopy by solving simplified radiosity equations describing flux transfers between canopy ensemble classes partitioned by vegetation layer and leaf slope. Integrated short-wave reflectance and transmittance-factors obtained from measured leaf optical properties were found to be nearly equal for the canopy studied. Short-wave view factor matrices were approximated by combining the average leaf scattering coefficient with the long-wave view factor matrices already incorporated in the model. Both the updated and original models were evaluated for a dense spruce fir forest study site in Central Maine. Canopy short-wave absorption coefficients estimated from detailed Monte Carlo ray tracing calculations were 0.60, 0.04, and 0.03 for the top, middle, and lower canopy layers corresponding to leaf area indices of 4.0, 1.05, and 0.25. The simplified radiosity technique yielded analogous absorption values of 0.55, 0.03, and 0.01. The resulting root mean square error in modeled versus measured canopy temperatures for all layers was less than 1°C with either technique. Maximum error in predicted temperature using the simplified radiosity technique was approximately 2°C during peak solar heating. (author)

Combined effects of traveling seismic waves and soil nonlinearity on nuclear power plant response

International Nuclear Information System (INIS)

Lee, T.H.; Charman, C.M.

1981-01-01

The effects of ground motion nonuniformity on the seismic input have been actively studied in recent years by considering the passage of traveling seismic waves. These studies gave rise to a new class of soil-structure interaction problems in which the seismic input is modified as a result of the spatial variations of ground motion. The phenomena were usually studied by using the elastic half-space simulation or discrete spring-models for modeling the soil medium. Finite element methods were also used recently on a limited scope. Results obtained from these investigations are often manifested by an attenuation of translational excitation along with an addition of rotational ground motion input. The decrease in structural response resulting from the input loss in the translational component was often insignificant since the response reduction tends to be offset by the effects from rotational input. The traveling wave effects have, so far, been investigated within the framework of linear theory with soil nonlinearity ignored. Conversely, the incorporation of soil nonlinearity in soil-structure interaction analyses has been done without including wave effect. Seismic analyses considering the hysteretic behavior of soil have been performed using highly idealized models for steady-state solution. More elaborate nonlinear seismic models deal with only the strain-dependent soil modulus rather than the transient unloading-reloading type of hysteretic characteristics of soil under a time-function input of earthquake trace. Apparently, the traveling wave effect and soil nonlinearity have been separately treated in the past. The purpose of this paper is to demonstrate that these two major effects can be combined in one model such that the influence of wave passage is reflected through the hysteretic behavior of soil particles, and thereby achieving significant reduction in seismic loads. (orig./RW)

Undamped electrostatic plasma waves

Energy Technology Data Exchange (ETDEWEB)

Valentini, F.; Perrone, D.; Veltri, P. [Dipartimento di Fisica and CNISM, Universita della Calabria, 87036 Rende (CS) (Italy); Califano, F.; Pegoraro, F. [Dipartimento di Fisica and CNISM, Universita di Pisa, 56127 Pisa (Italy); Morrison, P. J. [Institute for Fusion Studies and Department of Physics, University of Texas at Austin, Austin, Texas 78712-1060 (United States); O' Neil, T. M. [Department of Physics, University of California at San Diego, La Jolla, California 92093 (United States)

2012-09-15

Electrostatic waves in a collision-free unmagnetized plasma of electrons with fixed ions are investigated for electron equilibrium velocity distribution functions that deviate slightly from Maxwellian. Of interest are undamped waves that are the small amplitude limit of nonlinear excitations, such as electron acoustic waves (EAWs). A deviation consisting of a small plateau, a region with zero velocity derivative over a width that is a very small fraction of the electron thermal speed, is shown to give rise to new undamped modes, which here are named corner modes. The presence of the plateau turns off Landau damping and allows oscillations with phase speeds within the plateau. These undamped waves are obtained in a wide region of the (k,{omega}{sub R}) plane ({omega}{sub R} being the real part of the wave frequency and k the wavenumber), away from the well-known 'thumb curve' for Langmuir waves and EAWs based on the Maxwellian. Results of nonlinear Vlasov-Poisson simulations that corroborate the existence of these modes are described. It is also shown that deviations caused by fattening the tail of the distribution shift roots off of the thumb curve toward lower k-values and chopping the tail shifts them toward higher k-values. In addition, a rule of thumb is obtained for assessing how the existence of a plateau shifts roots off of the thumb curve. Suggestions are made for interpreting experimental observations of electrostatic waves, such as recent ones in nonneutral plasmas.

Undamped electrostatic plasma waves

International Nuclear Information System (INIS)

Valentini, F.; Perrone, D.; Veltri, P.; Califano, F.; Pegoraro, F.; Morrison, P. J.; O'Neil, T. M.

2012-01-01

Electrostatic waves in a collision-free unmagnetized plasma of electrons with fixed ions are investigated for electron equilibrium velocity distribution functions that deviate slightly from Maxwellian. Of interest are undamped waves that are the small amplitude limit of nonlinear excitations, such as electron acoustic waves (EAWs). A deviation consisting of a small plateau, a region with zero velocity derivative over a width that is a very small fraction of the electron thermal speed, is shown to give rise to new undamped modes, which here are named corner modes. The presence of the plateau turns off Landau damping and allows oscillations with phase speeds within the plateau. These undamped waves are obtained in a wide region of the (k,ω R ) plane (ω R being the real part of the wave frequency and k the wavenumber), away from the well-known “thumb curve” for Langmuir waves and EAWs based on the Maxwellian. Results of nonlinear Vlasov-Poisson simulations that corroborate the existence of these modes are described. It is also shown that deviations caused by fattening the tail of the distribution shift roots off of the thumb curve toward lower k-values and chopping the tail shifts them toward higher k-values. In addition, a rule of thumb is obtained for assessing how the existence of a plateau shifts roots off of the thumb curve. Suggestions are made for interpreting experimental observations of electrostatic waves, such as recent ones in nonneutral plasmas.

On new electromagnetic waves in a multicomponent insulator

NARCIS (Netherlands)

Dubovik, V. M.

The dispersion equation for additional transverse electromagnetic waves in a multicomponent amorphous insulator is analyzed in the vicinity of a narrow absorption line. Such waves can be excited due to spatial dispersion associated with fluctuation of the polarizability of insulator molecules. The

Harmonic effects on ion-bulk waves and simulation of stimulated ion-bulk-wave scattering in CH plasmas

Science.gov (United States)

Feng, Q. S.; Zheng, C. Y.; Liu, Z. J.; Cao, L. H.; Xiao, C. Z.; Wang, Q.; Zhang, H. C.; He, X. T.

2017-08-01

Ion-bulk (IBk) wave, a novel branch with a phase velocity close to the ion’s thermal velocity, discovered by Valentini et al (2011 Plasma Phys. Control. Fusion 53 105017), is recently considered as an important electrostatic activity in solar wind, and thus of great interest to space physics and also inertial confinement fusion. The harmonic effects on IBk waves has been researched by Vlasov simulation for the first time. The condition of excitation of the large-amplitude IBk waves is given. The nature of nonlinear IBk waves in the condition of kFeng scattering (SFS) has been proposed and also verified by Vlasov-Maxwell code. In CH plasmas, in addition to the stimulated Brillouin scattering from multi ion-acoustic waves, there exists SIBS simultaneously. This research gives an insight into the SIBS in the field of laser plasma interaction.

Cycloidal Wave Energy Converter

Energy Technology Data Exchange (ETDEWEB)

Stefan G. Siegel, Ph.D.

2012-11-30

This program allowed further advancing the development of a novel type of wave energy converter, a Cycloidal Wave Energy Converter or CycWEC. A CycWEC consists of one or more hydrofoils rotating around a central shaft, and operates fully submerged beneath the water surface. It operates under feedback control sensing the incoming waves, and converts wave power to shaft power directly without any intermediate power take off system. Previous research consisting of numerical simulations and two dimensional small 1:300 scale wave flume experiments had indicated wave cancellation efficiencies beyond 95%. The present work was centered on construction and testing of a 1:10 scale model and conducting two testing campaigns in a three dimensional wave basin. These experiments allowed for the first time for direct measurement of electrical power generated as well as the interaction of the CycWEC in a three dimensional environment. The Atargis team successfully conducted two testing campaigns at the Texas A&M Offshore Technology Research Center and was able to demonstrate electricity generation. In addition, three dimensional wave diffraction results show the ability to achieve wave focusing, thus increasing the amount of wave power that can be extracted beyond what was expected from earlier two dimensional investigations. Numerical results showed wave cancellation efficiencies for irregular waves to be on par with results for regular waves over a wide range of wave lengths. Using the results from previous simulations and experiments a full scale prototype was designed and its performance in a North Atlantic wave climate of average 30kW/m of wave crest was estimated. A full scale WEC with a blade span of 150m will deliver a design power of 5MW at an estimated levelized cost of energy (LCOE) in the range of 10-17 US cents per kWh. Based on the new results achieved in the 1:10 scale experiments these estimates appear conservative and the likely performance at full scale will

Wave tank to simulate the movement of oil under breaking waves

International Nuclear Information System (INIS)

Botrus, D.; Wickley-Olsen, E.; Boufadel, M.C.; Weaver, J.W.; Weggle, R.; Lee, K.; Venosa, A.D.

2008-01-01

Methods to mitigate offshore oil spills before they reach the shoreline have been investigated in order to reduce environmental impacts. Artificial dispersants are commonly used on offshore oil spills to decrease the interfacial tension between the oil and water. The wave action helps break the slick into droplets that penetrate into the sea. This paper presented the results of wave tank tests in which the effectiveness of dispersants was evaluated. The focus was on the transport of oil during the breakup of a wave. In this study, the energy dissipation rate per unit mass was evaluated at various depths in the tank for regular and breaking waves. It was shown that breaking waves play an important role in the dispersion of oil at sea. Contrary to previous studies which suggested that the plume moves forward following the breaker, the results of this study showed that the plume splits into two parts, with one part going upstream. Understanding how the plume travels will provide insight as to where to add the dispersant with respect to the location of the breaker. The addition of the dispersant should take place before the location of the breaker. It was concluded that future work should include computational fluid dynamics simulation, as well as the use of a higher resolution camera. 9 refs., 17 figs

Velocity Memory Effect for polarized gravitational waves

Science.gov (United States)

Zhang, P.-M.; Duval, C.; Gibbons, G. W.; Horvathy, P. A.

2018-05-01

Circularly polarized gravitational sandwich waves exhibit, as do their linearly polarized counterparts, the Velocity Memory Effect: freely falling test particles in the flat after-zone fly apart along straight lines with constant velocity. In the inside zone their trajectories combine oscillatory and rotational motions in a complicated way. For circularly polarized periodic gravitational waves some trajectories remain bounded, while others spiral outward. These waves admit an additional "screw" isometry beyond the usual five. The consequences of this extra symmetry are explored.

Lamb Wave Assessment of Fiber Volume Fraction in Composites

Science.gov (United States)

Seale, Michael D.; Smith, Barry T.; Prosser, W. H.; Zalameda, Joseph N.

1998-01-01

Among the various techniques available, ultrasonic Lamb waves offer a convenient method of examining composite materials. Since the Lamb wave velocity depends on the elastic properties of a material, an effective tool exists to evaluate composites by measuring the velocity of these waves. Lamb waves can propagate over long distances and are sensitive to the desired in-plane elastic properties of the material. This paper discusses a study in which Lamb waves were used to examine fiber volume fraction variations of approximately 0.40-0.70 in composites. The Lamb wave measurements were compared to fiber volume fractions obtained from acid digestion tests. Additionally, a model to predict the fiber volume fraction from Lamb wave velocity values was evaluated.

Nonlinear Water Waves

CERN Document Server

2016-01-01

This volume brings together four lecture courses on modern aspects of water waves. The intention, through the lectures, is to present quite a range of mathematical ideas, primarily to show what is possible and what, currently, is of particular interest. Water waves of large amplitude can only be fully understood in terms of nonlinear effects, linear theory being not adequate for their description. Taking advantage of insights from physical observation, experimental evidence and numerical simulations, classical and modern mathematical approaches can be used to gain insight into their dynamics. The book presents several avenues and offers a wide range of material of current interest. Due to the interdisciplinary nature of the subject, the book should be of interest to mathematicians (pure and applied), physicists and engineers. The lectures provide a useful source for those who want to begin to investigate how mathematics can be used to improve our understanding of water wave phenomena. In addition, some of the...

Niobium quarter-wave cavity for the New Delhi booster linac

International Nuclear Information System (INIS)

Shepard, K.W.; Roy, A.; Potukuchi, P.N.

1997-01-01

This paper reports the completion of development of a 97 Mhz niobium coaxial quarter-wave cavity to be used in a booster linac for the New Delhi 16UD pellatron electrostatic accelerator. A prototype cavity, which incorporates a niobium-bellows tuning device, has been completed and operated at 4.2 K at accelerating gradients above 4 MV/m for extended periods of time

Niobium quarter-wave cavity for the New Delhi booster linac

Energy Technology Data Exchange (ETDEWEB)

Shepard, K.W. [Argonne National Lab., IL (United States); Roy, A.; Potukuchi, P.N. [Nuclear Science Centre, New Delhi (India)

1997-09-01

This paper reports the completion of development of a 97 Mhz niobium coaxial quarter-wave cavity to be used in a booster linac for the New Delhi 16UD pellatron electrostatic accelerator. A prototype cavity, which incorporates a niobium-bellows tuning device, has been completed and operated at 4.2 K at accelerating gradients above 4 MV/m for extended periods of time.

Two-nucleon Hulthen-type interactions for few higher partial waves

Indian Academy of Sciences (India)

The Hamiltonian hierarchy problems in SQM lead to the addition of appropriate centrifugal barriers and consequently, higher partial wave potentials are ... the partial waves l > 0 one needs to improve the parameters involved in calculations. The present paper addresses itself to compute higher partial wave scattering phase ...

An Operator Method for Field Moments from the Extended Parabolic Wave Equation and Analytical Solutions of the First and Second Moments for Atmospheric Electromagnetic Wave Propagation

Science.gov (United States)

Manning, Robert M.

2004-01-01

The extended wide-angle parabolic wave equation applied to electromagnetic wave propagation in random media is considered. A general operator equation is derived which gives the statistical moments of an electric field of a propagating wave. This expression is used to obtain the first and second order moments of the wave field and solutions are found that transcend those which incorporate the full paraxial approximation at the outset. Although these equations can be applied to any propagation scenario that satisfies the conditions of application of the extended parabolic wave equation, the example of propagation through atmospheric turbulence is used. It is shown that in the case of atmospheric wave propagation and under the Markov approximation (i.e., the delta-correlation of the fluctuations in the direction of propagation), the usual parabolic equation in the paraxial approximation is accurate even at millimeter wavelengths. The comprehensive operator solution also allows one to obtain expressions for the longitudinal (generalized) second order moment. This is also considered and the solution for the atmospheric case is obtained and discussed. The methodology developed here can be applied to any qualifying situation involving random propagation through turbid or plasma environments that can be represented by a spectral density of permittivity fluctuations.

Guided wave crack detection and size estimation in stiffened structures

Science.gov (United States)

Bhuiyan, Md Yeasin; Faisal Haider, Mohammad; Poddar, Banibrata; Giurgiutiu, Victor

2018-03-01

Structural health monitoring (SHM) and nondestructive evaluation (NDE) deals with the nondestructive inspection of defects, corrosion, leaks in engineering structures by using ultrasonic guided waves. In the past, simplistic structures were often considered for analyzing the guided wave interaction with the defects. In this study, we focused on more realistic and relatively complicated structure for detecting any defect by using a non-contact sensing approach. A plate with a stiffener was considered for analyzing the guided wave interactions. Piezoelectric wafer active transducers were used to produce excitation in the structures. The excitation generated the multimodal guided waves (aka Lamb waves) that propagate in the plate with stiffener. The presence of stiffener in the plate generated scattered waves. The direct wave and the additional scattered waves from the stiffener were experimentally recorded and studied. These waves were considered as a pristine case in this research. A fine horizontal semi-circular crack was manufactured by using electric discharge machining in the same stiffener. The presence of crack in the stiffener produces additional scattered waves as well as trapped waves. These scattered waves and trapped wave modes from the cracked stiffener were experimentally measured by using a scanning laser Doppler vibrometer (SLDV). These waves were analyzed and compared with that from the pristine case. The analyses suggested that both size and shape of the horizontal crack may be predicted from the pattern of the scattered waves. Different features (reflection, transmission, and mode-conversion) of the scattered wave signals are analyzed. We found direct transmission feature for incident A0 wave mode and modeconversion feature for incident S0 mode are most suitable for detecting the crack in the stiffener. The reflection feature may give a better idea of sizing the crack.

Structural Loads Analysis for Wave Energy Converters: Preprint

Energy Technology Data Exchange (ETDEWEB)

van Rij, Jennifer A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Yu, Yi-Hsiang [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Guo, Yi [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-08-09

This study explores and verifies the generalized body-modes method for evaluating the structural loads on a wave energy converter (WEC). Historically, WEC design methodologies have focused primarily on accurately evaluating hydrodynamic loads, while methodologies for evaluating structural loads have yet to be fully considered and incorporated into the WEC design process. As wave energy technologies continue to advance, however, it has become increasingly evident that an accurate evaluation of the structural loads will enable an optimized structural design, as well as the potential utilization of composites and flexible materials, and hence reduce WEC costs. Although there are many computational fluid dynamics, structural analyses and fluid-structure-interaction (FSI) codes available, the application of these codes is typically too computationally intensive to be practical in the early stages of the WEC design process. The generalized body-modes method, however, is a reduced order, linearized, frequency-domain FSI approach, performed in conjunction with the linear hydrodynamic analysis, with computation times that could realistically be incorporated into the WEC design process. The objective of this study is to verify the generalized body-modes approach in comparison to high-fidelity FSI simulations to accurately predict structural deflections and stress loads in a WEC. Two verification cases are considered, a free-floating barge and a fixed-bottom column. Details for both the generalized body-modes models and FSI models are first provided. Results for each of the models are then compared and discussed. Finally, based on the verification results obtained, future plans for incorporating the generalized body-modes method into the WEC simulation tool, WEC-Sim, and the overall WEC design process are discussed.

Direct Drive Wave Energy Buoy

Energy Technology Data Exchange (ETDEWEB)

Rhinefrank, Kenneth [Columbia Power Technologies, Inc., Charlottesville, VA (United States); Lamb, Bradford [Columbia Power Technologies, Inc., Charlottesville, VA (United States); Prudell, Joseph [Columbia Power Technologies, Inc., Charlottesville, VA (United States); Hammagren, Erik [Columbia Power Technologies, Inc., Charlottesville, VA (United States); Lenee-Bluhm, Pukha [Columbia Power Technologies, Inc., Charlottesville, VA (United States)

2016-08-22

This Project aims to satisfy objectives of the DOE’s Water Power Program by completing a system detailed design (SDD) and other important activities in the first phase of a utility-scale grid-connected ocean wave energy demonstration. In early 2012, Columbia Power (CPwr) had determined that further cost and performance optimization was necessary in order to commercialize its StingRAY wave energy converter (WEC). CPwr’s progress toward commercialization, and the requisite technology development path, were focused on transitioning toward a commercial-scale demonstration. This path required significant investment to be successful, and the justification for this investment required improved annual energy production (AEP) and lower capital costs. Engineering solutions were developed to address these technical and cost challenges, incorporated into a proposal to the US Department of Energy (DOE), and then adapted to form the technical content and statement of project objectives of the resulting Project (DE-EE0005930). Through Project cost-sharing and technical collaboration between DOE and CPwr, and technical collaboration with Oregon State University (OSU), National Renewable Energy Lab (NREL) and other Project partners, we have demonstrated experimentally that these conceptual improvements have merit and made significant progress towards a certified WEC system design at a selected and contracted deployment site at the Wave Energy Test Site (WETS) at the Marine Corps Base in Oahu, HI (MCBH).

Hydromagnetic wave coupling in the magnetosphere

International Nuclear Information System (INIS)

Lee, D.

1990-01-01

The hydromagnetic wave phenomena in the magnetosphere has been an area of space physics and plasma physics where theory has been successful in explaining many features in satellite experiments and ground-based observations. Magnetohydrodynamic (MHD) waves, which are composed of transverse Alven waves and compressional waves, are usually coupled in space due to an inhomogeneous plasma density and curved magnetic field lines. In addition to these effects, hot temperature plasmas invoke various ultra low frequency (ULF) wave phenomena via macroscopic wave instabilities or wave particle resonant interactions. These properties of the coupling between the two different MHD waves were analytically and numerically studied in a simplified model such as the box model with straight field lines. However, the real magnetosphere is rather close to a dipole field, even though the night side of the magnetosphere is significantly distorted from dipole geometry. The curvature of field lines plays an important role in understanding hydromagnetic wave coupling in the magnetosphere since the MHD wave propagation depends strongly on the curved magnetic fields. The study of the hydromagnetic wave properties on an inhomogeneous and curved magnetic field system by considering realistic geometry is emphasized. Most of the current theories are reviewed and a number of observations are introduced according to the wave excitation mechanism. Studies are also performed with the development of numerical models such as the two and three dimensional MHD dipole models. An attempt is made to understand and classify the hydromagnetic wave behavior in inhomogeneous and hot plasmas with respect to the energy sources and their frequency band in the magnetosphere. Therefore, various excitation mechanisms for hydromagnetic waves are examined to compare analytical and numerical results with the observations

Short-Period Surface Wave Based Seismic Event Relocation

Science.gov (United States)

White-Gaynor, A.; Cleveland, M.; Nyblade, A.; Kintner, J. A.; Homman, K.; Ammon, C. J.

2017-12-01

Accurate and precise seismic event locations are essential for a broad range of geophysical investigations. Superior location accuracy generally requires calibration with ground truth information, but superb relative location precision is often achievable independently. In explosion seismology, low-yield explosion monitoring relies on near-source observations, which results in a limited number of observations that challenges our ability to estimate any locations. Incorporating more distant observations means relying on data with lower signal-to-noise ratios. For small, shallow events, the short-period (roughly 1/2 to 8 s period) fundamental-mode and higher-mode Rayleigh waves (including Rg) are often the most stable and visible portion of the waveform at local distances. Cleveland and Ammon [2013] have shown that teleseismic surface waves are valuable observations for constructing precise, relative event relocations. We extend the teleseismic surface wave relocation method, and apply them to near-source distances using Rg observations from the Bighorn Arche Seismic Experiment (BASE) and the Earth Scope USArray Transportable Array (TA) seismic stations. Specifically, we present relocation results using short-period fundamental- and higher-mode Rayleigh waves (Rg) in a double-difference relative event relocation for 45 delay-fired mine blasts and 21 borehole chemical explosions. Our preliminary efforts are to explore the sensitivity of the short-period surface waves to local geologic structure, source depth, explosion magnitude (yield), and explosion characteristics (single-shot vs. distributed source, etc.). Our results show that Rg and the first few higher-mode Rayleigh wave observations can be used to constrain the relative locations of shallow low-yield events.

Ion Bernstein wave heating research

International Nuclear Information System (INIS)

Ono, Masayuki.

1992-03-01

Ion Bernstein wave heating (IBWH) utilizes the ion Bernstein wave (IBW), a hot plasma wave, to carry the radio frequency (rf) power to heat tokamak reactor core. Earlier wave accessibility studies have shown that this finite-Larmor-radius (FLR) mode should penetrate into a hot dense reactor plasma core without significant attenuation. Moreover, the IBW's low phase velocity (ω/k perpendicular ∼ V Ti much-lt V α ) greatly reduces the otherwise serious wave absorption by the 3.5 MeV fusion α-particles. In addition, the property of IBW's that k perpendicular ρ i ∼ 1 makes localized bulk ion heating possible at the ion cyclotron harmonic layers. Such bulk ion heating can prove useful in optimizing fusion reactivity. In another vein, with proper selection of parameters, IBW's can be made subject to strong localized electron Landau damping near the major ion cyclotron harmonic resonance layers. This property can be useful, for example, for rf current drive in the reactor plasma core. This paper discusses this research

The Potential for Ambient Plasma Wave Propulsion

Science.gov (United States)

Gilland, James H.; Williams, George J.

2016-01-01

A truly robust space exploration program will need to make use of in-situ resources as much as possible to make the endeavor affordable. Most space propulsion concepts are saddled with one fundamental burden; the propellant needed to produce momentum. The most advanced propulsion systems currently in use utilize electric and/or magnetic fields to accelerate ionized propellant. However, significant planetary exploration missions in the coming decades, such as the now canceled Jupiter Icy Moons Orbiter, are restricted by propellant mass and propulsion system lifetimes, using even the most optimistic projections of performance. These electric propulsion vehicles are inherently limited in flexibility at their final destination, due to propulsion system wear, propellant requirements, and the relatively low acceleration of the vehicle. A few concepts are able to utilize the environment around them to produce thrust: Solar or magnetic sails and, with certain restrictions, electrodynamic tethers. These concepts focus primarily on using the solar wind or ambient magnetic fields to generate thrust. Technically immature, quasi-propellantless alternatives lack either the sensitivity or the power to provide significant maneuvering. An additional resource to be considered is the ambient plasma and magnetic fields in solar and planetary magnetospheres. These environments, such as those around the Sun or Jupiter, have been shown to host a variety of plasma waves. Plasma wave propulsion takes advantage of an observed astrophysical and terrestrial phenomenon: Alfven waves. These are waves that propagate in the plasma and magnetic fields around and between planets and stars. The generation of Alfven waves in ambient magnetic and plasma fields to generate thrust is proposed as a truly propellantless propulsion system which may enable an entirely new matrix of exploration missions. Alfven waves are well known, transverse electromagnetic waves that propagate in magnetized plasmas at

Effects of vortex-like and non-thermal ion distributions on non-linear dust-acoustic waves

International Nuclear Information System (INIS)

Mamun, A.A.; Cairns, R.A.; Shukla, P.K.

1996-01-01

The effects of vortex-like and non-thermal ion distributions are incorporated in the study of nonlinear dust-acoustic waves in an unmagnetized dusty plasma. It is found that owing to the departure from the Boltzmann ion distribution to a vortex-like phase space distribution, the dynamics of small but finite amplitude dust-acoustic waves is governed by a modified Kortweg endash de Vries equation. The latter admits a stationary dust-acoustic solitary wave solution, which has larger amplitude, smaller width, and higher propagation velocity than that involving adiabatic ions. On the other hand, consideration of a non-thermal ion distribution provides the possibility of coexistence of large amplitude rarefactive as well as compressive dust-acoustic solitary waves, whereas these structures appear independently when the wave amplitudes become infinitely small. The present investigation should help us to understand the salient features of the non-linear dust-acoustic waves that have been observed in a recent numerical simulation study. copyright 1996 American Institute of Physics

Circuit quantum acoustodynamics with surface acoustic waves.

Science.gov (United States)

Manenti, Riccardo; Kockum, Anton F; Patterson, Andrew; Behrle, Tanja; Rahamim, Joseph; Tancredi, Giovanna; Nori, Franco; Leek, Peter J

2017-10-17

The experimental investigation of quantum devices incorporating mechanical resonators has opened up new frontiers in the study of quantum mechanics at a macroscopic level. It has recently been shown that surface acoustic waves (SAWs) can be piezoelectrically coupled to superconducting qubits, and confined in high-quality Fabry-Perot cavities in the quantum regime. Here we present measurements of a device in which a superconducting qubit is coupled to a SAW cavity, realising a surface acoustic version of cavity quantum electrodynamics. We use measurements of the AC Stark shift between the two systems to determine the coupling strength, which is in agreement with a theoretical model. This quantum acoustodynamics architecture may be used to develop new quantum acoustic devices in which quantum information is stored in trapped on-chip acoustic wavepackets, and manipulated in ways that are impossible with purely electromagnetic signals, due to the 10 5 times slower mechanical waves.In this work, Manenti et al. present measurements of a device in which a tuneable transmon qubit is piezoelectrically coupled to a surface acoustic wave cavity, realising circuit quantum acoustodynamic architecture. This may be used to develop new quantum acoustic devices.

Extracorporeal shock wave therapy in periodontics: A new paradigm.

Science.gov (United States)

Venkatesh Prabhuji, Munivenkatappa Lakshmaiah; Khaleelahmed, Shaeesta; Vasudevalu, Sujatha; Vinodhini, K

2014-05-01

The quest for exploring new frontiers in the field of medical science for efficient and improved treatment modalities has always been on a rise. Extracorporeal shock wave therapy (ESWT) has been enormously used in medical practice, principally, for the management of urolithiasis, cholelithiasis and also in various orthopedic and musculoskeletal disorders. The efficacy of ESWT in the stimulation of osteoblasts, fibroblasts, induction of neovascularization and increased expression of bone morphogenic proteins has been well documented in the literature. However, dentistry is no exception to this trend. The present article enlightens the various applications of ESWT in the field of dentistry and explores its prospective applications in the field of periodontics, and the possibility of incorporating the beneficial properties of shock waves in improving the treatment outcome.

Photoreversible Covalent Hydrogels for Soft-Matter Additive Manufacturing.

Science.gov (United States)

Kabb, Christopher P; O'Bryan, Christopher S; Deng, Christopher C; Angelini, Thomas E; Sumerlin, Brent S

2018-05-16

Reversible covalent chemistry provides access to robust materials with the ability to be degraded and reformed upon exposure to an appropriate stimulus. Photoresponsive units are attractive for this purpose, as the spatial and temporal application of light is easily controlled. Coumarin derivatives undergo a [2 + 2] cycloaddition upon exposure to long-wave UV irradiation (365 nm), and this process can be reversed using short-wave UV light (254 nm). Therefore, polymers cross-linked by coumarin groups are excellent candidates as reversible covalent gels. In this work, copolymerization of coumarin-containing monomers with the hydrophilic comonomer N, N-dimethylacrylamide yielded water-soluble, linear polymers that could be cured with long-wave UV light into free-standing hydrogels, even in the absence of a photoinitiator. Importantly, the gels were reverted back to soluble copolymers upon short-wave UV irradiation. This process could be cycled, allowing for recycling and remolding of the hydrogel into additional shapes. Further, this hydrogel can be imprinted with patterns through a mask-based, post-gelation photoetching method. Traditional limitations of this technique, such as the requirement for uniform etching in one direction, have been overcome by combining these materials with a soft-matter additive manufacturing methodology. In a representative application of this approach, we printed solid structures in which the interior coumarin-cross-linked gel is surrounded by a nondegradable gel. Upon exposure to short-wave UV irradiation, the coumarin-cross-linked gel was reverted to soluble prepolymers that were washed away to yield hollow hydrogel objects.

Dopant Adsorption and Incorporation at Irradiated GaN Surfaces

Science.gov (United States)

Sun, Qiang; Selloni, Annabella; Myers, Thomas; Doolittle, W. Alan

2006-03-01

Mg and O are two of the common dopants in GaN, but, in spite of extensive investigation, the atomic scale understanding of their adsorption and incorporation is still incomplete. In particular, high-energy electron irradiation, such as occurring during RHEED, has been reported to have an important effect on the incorporation of these impurities, but no study has addressed the detailed mechanisms of this effect yet. Here we use DFT calculations to study the adsorption and incorporation of Mg and O at the Ga- and N-polar GaN surfaces under various Ga, Mg and O coverage conditions as well as in presence of light or electron beam-induced electronic excitation. We find that the adsorption and incorporation of the two impurities have opposite surface polarity dependence: substitutional Mg prefers to incorporate at the GaN(0001) surface, while O prefers to adsorb and incorporate at the N-polar surface. In addition, our results indicate that in presence of light irradiation the tendency of Mg to surface-segregate is reduced. The O adsorption energy on the N-polar surface is also significantly reduced, consistent with the experimental observation of a much smaller concentration of oxygen in the irradiated samples.

Three-dimensional freak waves and higher-order wave-wave resonances

Science.gov (United States)

Badulin, S. I.; Ivonin, D. V.; Dulov, V. A.

2012-04-01

Quite often the freak wave phenomenon is associated with the mechanism of modulational (Benjamin-Feir) instability resulted from resonances of four waves with close directions and scales. This weakly nonlinear model reflects some important features of the phenomenon and is discussing in a great number of studies as initial stage of evolution of essentially nonlinear water waves. Higher-order wave-wave resonances attract incomparably less attention. More complicated mathematics and physics explain this disregard partially only. The true reason is a lack of adequate experimental background for the study of essentially three-dimensional water wave dynamics. We start our study with the classic example of New Year Wave. Two extreme events: the famous wave 26.5 meters and one of smaller 18.5 meters height (formally, not freak) of the same record, are shown to have pronounced features of essentially three-dimensional five-wave resonant interactions. The quasi-spectra approach is used for the data analysis in order to resolve adequately frequencies near the spectral peak fp ≈ 0.057Hz and, thus, to analyze possible modulations of the dominant wave component. In terms of the quasi-spectra the above two anomalous waves show co-existence of the peak harmonic and one at frequency f5w = 3/2fp that corresponds to maximum of five-wave instability of weakly nonlinear waves. No pronounced marks of usually discussed Benjamin-Feir instability are found in the record that is easy to explain: the spectral peak frequency fp corresponds to the non-dimensional depth parameter kD ≈ 0.92 (k - wavenumber, D ≈ 70 meters - depth at the Statoil platform Draupner site) that is well below the shallow water limit of the instability kD = 1.36. A unique data collection of wave records of the Marine Hydrophysical Institute in the Katsiveli platform (Black Sea) has been analyzed in view of the above findings of possible impact of the five-wave instability on freak wave occurrence. The data cover

A metasurface carpet cloak for electromagnetic, acoustic and water waves.

Science.gov (United States)

Yang, Yihao; Wang, Huaping; Yu, Faxin; Xu, Zhiwei; Chen, Hongsheng

2016-01-29

We propose a single low-profile skin metasurface carpet cloak to hide objects with arbitrary shape and size under three different waves, i.e., electromagnetic (EM) waves, acoustic waves and water waves. We first present a metasurface which can control the local reflection phase of these three waves. By taking advantage of this metasurface, we then design a metasurface carpet cloak which provides an additional phase to compensate the phase distortion introduced by a bump, thus restoring the reflection waves as if the incident waves impinge onto a flat mirror. The finite element simulation results demonstrate that an object can be hidden under these three kinds of waves with a single metasurface cloak.

Role of various Dirac covariants in the BS wave functions in decay constant calculations of pseudoscalar mesons using a power counting scheme

International Nuclear Information System (INIS)

Bhatnagar, S.; Mahecha, J.

2008-09-01

We have employed the framework of Bethe-Salpeter equation under Covariant Instantaneous Ansatz to calculate the leptonic decay constants of unequal mass pseudoscalar mesons. In the Dirac structure of BS wave function, the covariants are incorporated from their complete set in accordance with a recently proposed power counting rule, order-by-order in powers of inverse of meson mass. The decay constants are calculated incorporating both Leading Order (LO) as well as Next-to-leading Order (NLO) Dirac covariants. The contribution of both LO as well as NLO covariants to decay constants are studied in detail in this paper. The results are found to improve dramatically, and hence validating the power counting rule which also provides a practical means of incorporating Dirac covariants in the BS wave function of a hadron. (author)

Continuous wave room temperature external ring cavity quantum cascade laser

Energy Technology Data Exchange (ETDEWEB)

Revin, D. G., E-mail: d.revin@sheffield.ac.uk; Hemingway, M.; Vaitiekus, D.; Cockburn, J. W. [Physics and Astronomy Department, The University of Sheffield, S3 7RH Sheffield (United Kingdom); Hempler, N.; Maker, G. T.; Malcolm, G. P. A. [M Squared Lasers Ltd., G20 0SP Glasgow (United Kingdom)

2015-06-29

An external ring cavity quantum cascade laser operating at ∼5.2 μm wavelength in a continuous-wave regime at the temperature of 15 °C is demonstrated. Out-coupled continuous-wave optical powers of up to 23 mW are observed for light of one propagation direction with an estimated total intra-cavity optical power flux in excess of 340 mW. The uni-directional regime characterized by the intensity ratio of more than 60 for the light propagating in the opposite directions was achieved. A single emission peak wavelength tuning range of 90 cm{sup −1} is realized by the incorporation of a diffraction grating into the cavity.

Continuous wave room temperature external ring cavity quantum cascade laser

International Nuclear Information System (INIS)

Revin, D. G.; Hemingway, M.; Vaitiekus, D.; Cockburn, J. W.; Hempler, N.; Maker, G. T.; Malcolm, G. P. A.

2015-01-01

An external ring cavity quantum cascade laser operating at ∼5.2 μm wavelength in a continuous-wave regime at the temperature of 15 °C is demonstrated. Out-coupled continuous-wave optical powers of up to 23 mW are observed for light of one propagation direction with an estimated total intra-cavity optical power flux in excess of 340 mW. The uni-directional regime characterized by the intensity ratio of more than 60 for the light propagating in the opposite directions was achieved. A single emission peak wavelength tuning range of 90 cm −1 is realized by the incorporation of a diffraction grating into the cavity

Light Diffraction by Large Amplitude Ultrasonic Waves in Liquids

Science.gov (United States)

Adler, Laszlo; Cantrell, John H.; Yost, William T.

2016-01-01

Light diffraction from ultrasound, which can be used to investigate nonlinear acoustic phenomena in liquids, is reported for wave amplitudes larger than that typically reported in the literature. Large amplitude waves result in waveform distortion due to the nonlinearity of the medium that generates harmonics and produces asymmetries in the light diffraction pattern. For standing waves with amplitudes above a threshold value, subharmonics are generated in addition to the harmonics and produce additional diffraction orders of the incident light. With increasing drive amplitude above the threshold a cascade of period-doubling subharmonics are generated, terminating in a region characterized by a random, incoherent (chaotic) diffraction pattern. To explain the experimental results a toy model is introduced, which is derived from traveling wave solutions of the nonlinear wave equation corresponding to the fundamental and second harmonic standing waves. The toy model reduces the nonlinear partial differential equation to a mathematically more tractable nonlinear ordinary differential equation. The model predicts the experimentally observed cascade of period-doubling subharmonics terminating in chaos that occurs with increasing drive amplitudes above the threshold value. The calculated threshold amplitude is consistent with the value estimated from the experimental data.

Three-dimensional instability of standing waves

Science.gov (United States)

Zhu, Qiang; Liu, Yuming; Yue, Dick K. P.

2003-12-01

We investigate the three-dimensional instability of finite-amplitude standing surface waves under the influence of gravity. The analysis employs the transition matrix (TM) approach and uses a new high-order spectral element (HOSE) method for computation of the nonlinear wave dynamics. HOSE is an extension of the original high-order spectral method (HOS) wherein nonlinear wave wave and wave body interactions are retained up to high order in wave steepness. Instead of global basis functions in HOS, however, HOSE employs spectral elements to allow for complex free-surface geometries and surface-piercing bodies. Exponential convergence of HOS with respect to the total number of spectral modes (for a fixed number of elements) and interaction order is retained in HOSE. In this study, we use TM-HOSE to obtain the stability of general three-dimensional perturbations (on a two-dimensional surface) on two classes of standing waves: plane standing waves in a rectangular tank; and radial/azimuthal standing waves in a circular basin. For plane standing waves, we confirm the known result of two-dimensional side-bandlike instability. In addition, we find a novel three-dimensional instability for base flow of any amplitude. The dominant component of the unstable disturbance is an oblique (standing) wave oriented at an arbitrary angle whose frequency is close to the (nonlinear) frequency of the original standing wave. This finding is confirmed by direct long-time simulations using HOSE which show that the nonlinear evolution leads to classical Fermi Pasta Ulam recurrence. For the circular basin, we find that, beyond a threshold wave steepness, a standing wave (of nonlinear frequency Omega) is unstable to three-dimensional perturbations. The unstable perturbation contains two dominant (standing-wave) components, the sum of whose frequencies is close to 2Omega. From the cases we consider, the critical wave steepness is found to generally decrease/increase with increasing radial

Simulation of Asymmetric Lamb Waves for Sensing and Actuation in Plates

Directory of Open Access Journals (Sweden)

A. Ghoshal

2005-01-01

Full Text Available Two approaches used for monitoring the health of thin aerospace structures are active interrogation and passive monitoring. The active interrogation approach generates and receives diagnostic Lamb waves to detect damage, while the passive monitoring technique listens for acoustic waves caused by damage growth. For the application of both methods, it is necessary to understand how Lamb waves propagate through a structure. In this paper, a Physics-Based Model (PBM using classical plate theory is developed to provide a basic understanding of the actual physical process of asymmetric Lamb mode wave generation and propagation in a plate. The closed-form model uses modal superposition to simulate waves generated by piezoceramic patches and by simulated acoustic emissions. The generation, propagation, reflection, interference, and the sensing of the waves are represented in the model, but damage is not explicitly modeled. The developed model is expected to be a useful tool for the Structural Health Monitoring (SHM community, particularly for studying high frequency acoustic wave generation and propagation in lieu of Finite Element models and other numerical models that require significant computational resources. The PBM is capable of simulating many possible scenarios including a variety of test cases, whereas experimental measurements of all of the cases can be costly and time consuming. The model also incorporates the sensor measurement effect, which is an important aspect in damage detection. Continuous and array sensors are modeled, which are efficient for measuring waves because of their distributed nature.

Wave Propagation in Bimodular Geomaterials

Science.gov (United States)

Kuznetsova, Maria; Pasternak, Elena; Dyskin, Arcady; Pelinovsky, Efim

2016-04-01

Observations and laboratory experiments show that fragmented or layered geomaterials have the mechanical response dependent on the sign of the load. The most adequate model accounting for this effect is the theory of bimodular (bilinear) elasticity - a hyperelastic model with different elastic moduli for tension and compression. For most of geo- and structural materials (cohesionless soils, rocks, concrete, etc.) the difference between elastic moduli is such that their modulus in compression is considerably higher than that in tension. This feature has a profound effect on oscillations [1]; however, its effect on wave propagation has not been comprehensively investigated. It is believed that incorporation of bilinear elastic constitutive equations within theory of wave dynamics will bring a deeper insight to the study of mechanical behaviour of many geomaterials. The aim of this paper is to construct a mathematical model and develop analytical methods and numerical algorithms for analysing wave propagation in bimodular materials. Geophysical and exploration applications and applications in structural engineering are envisaged. The FEM modelling of wave propagation in a 1D semi-infinite bimodular material has been performed with the use of Marlow potential [2]. In the case of the initial load expressed by a harmonic pulse loading strong dependence on the pulse sign is observed: when tension is applied before compression, the phenomenon of disappearance of negative (compressive) strains takes place. References 1. Dyskin, A., Pasternak, E., & Pelinovsky, E. (2012). Periodic motions and resonances of impact oscillators. Journal of Sound and Vibration, 331(12), 2856-2873. 2. Marlow, R. S. (2008). A Second-Invariant Extension of the Marlow Model: Representing Tension and Compression Data Exactly. In ABAQUS Users' Conference.

Wind and waves: becoming serious Australian industries

International Nuclear Information System (INIS)

Anon

1999-01-01

Renewable energy is emerging as a critical policy issue in Australia following the Federal Government's 2% target for renewable energy. Adding to the potential for renewable energy in Victoria, Primergy in conjunction with its newly acquired subsidiary Renewable Energy Australia Pacific (REAP) Wind Pty Ltd has secured the exclusive license for the construction, operation and sale of, an advanced technology wind turbine throughout Australia and regional markets. Primergy believes that the potential market for wind generation in Australia could be between 500 to 800 MW or 700 to 1200 wind turbines. The company has also entered into a joint venture with Energetech and is funding 50% of the total cost to build the first wave machine which would be completed at Port Kembla, near Wollongong, by the end of 2000. The wave generator uses an innovative new concept incorporating an highly efficient air driven turbine

Third Wave of Cognitive Behavioral Therapies

Directory of Open Access Journals (Sweden)

Sevginar Vatan

Full Text Available The psychological functioning of an individual includes well-being, cognitions, emotions and behaviors as a whole. In the current models of psychopathologies, as similar to well-being, reciprocal interaction between emotions, behaviors and cognitions is emphasized. Notwithstanding that the effects of these three components on cognitive behavior therapies can be mentioned too, it can be claimed that emotions were remained in the background by the behaviors and cognitions until the third wave of cognitive behavior therapies. Emotions have became prominent with the third wave approaches in the field of cognitive behavior therapy. In this review article, similarities and differences of third wave of cognitive behavior therapy with other waves, the constructs of emotion and emotion regulation in the third wave and the impacts of these on treatment were included. Additionally, throughout this perspective, treatment processes focusing on emotion regulation skills were discussed. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2016; 8(3.000: 190-203

Application of multi-parameter chorus and plasmaspheric hiss wave models in radiation belt modeling

Science.gov (United States)

Aryan, H.; Kang, S. B.; Balikhin, M. A.; Fok, M. C. H.; Agapitov, O. V.; Komar, C. M.; Kanekal, S. G.; Nagai, T.; Sibeck, D. G.

2017-12-01

Numerical simulation studies of the Earth's radiation belts are important to understand the acceleration and loss of energetic electrons. The Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model along with many other radiation belt models require inputs for pitch angle, energy, and cross diffusion of electrons, due to chorus and plasmaspheric hiss waves. These parameters are calculated using statistical wave distribution models of chorus and plasmaspheric hiss amplitudes. In this study we incorporate recently developed multi-parameter chorus and plasmaspheric hiss wave models based on geomagnetic index and solar wind parameters. We perform CIMI simulations for two geomagnetic storms and compare the flux enhancement of MeV electrons with data from the Van Allen Probes and Akebono satellites. We show that the relativistic electron fluxes calculated with multi-parameter wave models resembles the observations more accurately than the relativistic electron fluxes calculated with single-parameter wave models. This indicates that wave models based on a combination of geomagnetic index and solar wind parameters are more effective as inputs to radiation belt models.

Effect of pumpkin powder incorporation on cooking and sensory parameters of pasta

Directory of Open Access Journals (Sweden)

Lucia Minarovičová

2017-01-01

Full Text Available Pasta is commonly consumed and low glycaemic cereal-based food with long shelf life, which is suitable food matrix for substitution with functional ingredients. Pumpkin powder can be considered as suitable component in pasta making. The effect of addition of pumpkin powder at different levels (5, 7.5, and 10% on wheat dough rheology, cooking quality of pasta as well as on sensory properties was evaluated. Pumpkin powder included: 6.1% moisture, 8.2%, protein, 0.7% crude fat, 2.3% ash, 27.4% total dietary fiber which is included soluble (10.2% and insoluble (17.2% dietary fiber. Farinograph properties of pumpkin powder incorporated dough showed increase in water absorption and dough development time while dough stability and mixing tolerance indes were decreased. It was also observed that addition of pumpkin powder significantly altered cooking quality of pasta. Generally, pasta incorporated with pumpkin powder had shorter optimal cooking time. The shortest optimal time (5.9 min was after addition of 10% of pumpkin powder compared with control pasta (7.0 min. From the results also concluded that addition of pumpkin powder significantly increased cooking loss. The highest cooking loss (6.6% was after addition 10% pumpkin powder. Furthermore it could be stated that incorporation of pumpkin powder in pasta increased water absorption of pasta from 181.0% (control to 211.2% (10% of pumpkin powder. From sensory evaluation resulted that pumpkin powder incorporated pasta were characterized by lower colour, flavor and grain taste. On the other hand vegetable taste and granular structure of pasta increased with higher addition level of pumpkin powder. Moreover, it was concluded that pasta with addition level 10% were the most acceptable for accesors. Normal 0 21 false false false EN-GB X-NONE X-NONE Normal 0 21 false false false EN-GB X-NONE X-NONE

Temporal change in shallow subsurface P- and S-wave velocities and S-wave anisotropy inferred from coda wave interferometry

Science.gov (United States)

Yamamoto, M.; Nishida, K.; Takeda, T.

2012-12-01

logarithm of the lapse time. At some stations, the estimated P-wave velocity also shows co-seismic velocity decrease and subsequent gradual recovery. However, the magnitude of estimated P-wave velocity change is much smaller than that of S-wave, and at the other stations, the magnitude of P-wave velocity change is smaller than the resolution of our analysis. Using the CCFs computed from horizontal components, we also determine the seismic anisotropy in subsurface structure, and examine its temporal change. The estimated strength of anisotropy strength shows co-seismic increase at most of stations where co-seismic velocity change is detected. Nevertheless, the direction of anisotropy after the 2011 Tohoku earthquake stays about the same as before. These results suggest that, in addition to the change in pore pressure and corresponding decrease in the rigidity, the change in the aspect ratio of pre-existing subsurface fractures/micro-crack may be another key mechanism causing the co-seismic velocity change in shallow subsurface structures.

Impact of an offshore wind farm on wave conditions and shoreline development

DEFF Research Database (Denmark)

Christensen, Erik Damgaard; Kristensen, Sten Esbjørn; Deigaard, Rolf

2014-01-01

the shoreline’s sensitivity to the distance from the OWF to the shoreline was studied. The effect of the reduced wind speed inside and on the lee side of the offshore wind farm was incorporated in a parameterized way in a spectral wind wave model. The shoreline impact was studied with a one-line model....

Buoy and Generator Interaction with Ocean Waves: Studies of a Wave Energy Conversion System

Energy Technology Data Exchange (ETDEWEB)

Lindroth, Simon

2011-07-01

On March 13th, 2006, the Div. of Electricity at Uppsala Univ. deployed its first wave energy converter, L1, in the ocean southwest of Lysekil. L1 consisted of a buoy at the surface, connected through a line to a linear generator on the seabed. Since the deployment, continuous investigations of how L1 works in the waves have been conducted, and several additional wave energy converters have been deployed. This thesis is based on ten publications, which focus on different aspects of the interaction between wave, buoy, and generator. In order to evaluate different measurement systems, the motion of the buoy was measured optically and using accelerometers, and compared to measurements of the motion of the movable part of the generator - the translator. These measurements were found to correlate well. Simulations of buoy and translator motion were found to match the measured values. The variation of performance of L1 with changing water levels, wave heights, and spectral shapes was also investigated. Performance is here defined as the ratio of absorbed power to incoming power. It was found that the performance decreases for large wave heights. This is in accordance with the theoretical predictions, since the area for which the stator and the translator overlap decreases for large translator motions. Shifting water levels were predicted to have the same effect, but this could not be seen as clearly. The width of the wave energy spectrum has been proposed by some as a factor that also affects the performance of a wave energy converter, for a set wave height and period. Therefore the relation between performance and several different parameters for spectral width was investigated. It was found that some of the parameters were in fact correlated to performance, but that the correlation was not very strong. As a background on ocean measurements in wave energy, a thorough literature review was conducted. It turns out that the Lysekil project is one of quite few projects that

Travelling waves in models of neural tissue: from localised structures to periodic waves

NARCIS (Netherlands)

Meijer, Hil Gaétan Ellart; Coombes, Stephen

2014-01-01

We consider travelling waves (fronts, pulses and periodics) in spatially extended one dimensional neural field models. We demonstrate for an excitatory field with linear adaptation that, in addition to an expected stable pulse solution, a stable anti-pulse can exist. Varying the adaptation strength

Metamaterials, from electromagnetic waves to water waves, bending waves and beyond

KAUST Repository

Dupont, G.

2015-08-04

We will review our recent work on metamaterials for different types of waves. Transposition of transform optics to water waves and bending waves on plates will be considered with potential applications of cloaking to water waves protection and anti-vibrating systems.

Identification of waves by RF magnetic probes during lower hybrid wave injection experiments on the TST-2 spherical tokamak

International Nuclear Information System (INIS)

Shinya, Takahiro; Ejiri, Akira; Takase, Yuichi

2014-01-01

RF magnetic probes can be used to measure not only the wavevector, but also the polarization of waves in plasmas. A 5-channel RF magnetic probe (5ch-RFMP) was installed in the TST-2 spherical tokamak and the waves were studied in detail during lower hybrid wave injection experiments. From the polarization measurements, the poloidal RF magnetic field is found to be dominant. In addition to polarization, components of k perpendicular to the major radial direction were obtained from phase differences among the five channels. The radial wavenumber was obtained by scanning the radial position of the 5ch-RFMP on a shot by shot basis. The measured wavevector and polarization in the plasma edge region were consistent with those calculated from the wave equation for the slow wave branch. While the waves with small and large k ∥ were excited by the antenna, only the small k ∥ component was measured by the 5ch-RFMP; this suggests that the waves with larger k ∥ were absorbed by the plasma. (author)

Boson-triboson Scattering with Yamaguchi potential. 2. Inclusion of additional p-wave component for the 3+1-subamplitude

International Nuclear Information System (INIS)

Matsui, Yoshiko

1999-01-01

In order to investigate the p-wave contribution from the 3+1-subamplitude in the S-wave phase shift for boson-triboson elastic scattering when the Yamaguchi potential for the two-body interaction is assumed, the Faddeev-Osborn equation for a system of four identical bosons in solved numerically by extending the previous calculation to include the p-wave component for the 3+1-subamplitude. The results obtained closely resemble the previous results. The calculated phase shift generally has the standard behavior of the two-body phase shift for a loosely bound state and has further characteristic behavior represented by a valley witha peak as fine structure. The phase shift obtained in the present calculation has a higher peak and a deeper valley than the previous one, while the positions of the peak and the valley in the two sets of results agree precisely. Thus the calculated resonance energies are the same as those obtained in the previous result. (author)

Impact of Wave Dragon on Wave Climate

DEFF Research Database (Denmark)

Andersen, Thomas Lykke; Tedd, James; Kramer, Morten

This report is an advisory paper for use in determining the wave dragon effects on hydrography, by considering the effect on the wave climate in the region of a wave dragon. This is to be used in the impact assessment for the Wave Dragon pre-commercial demonstrator.......This report is an advisory paper for use in determining the wave dragon effects on hydrography, by considering the effect on the wave climate in the region of a wave dragon. This is to be used in the impact assessment for the Wave Dragon pre-commercial demonstrator....

Effective Orthorhombic Anisotropic Models for Wave field Extrapolation

KAUST Repository

Ibanez Jacome, Wilson

2013-05-01

Wavefield extrapolation in orthorhombic anisotropic media incorporates complicated but realistic models, to reproduce wave propagation phenomena in the Earth\\'s subsurface. Compared with the representations used for simpler symmetries, such as transversely isotropic or isotropic, orthorhombic models require an extended and more elaborated formulation that also involves more expensive computational processes. The acoustic assumption yields more efficient description of the orthorhombic wave equation that also provides a simplified representation for the orthorhombic dispersion relation. However, such representation is hampered by the sixth-order nature of the acoustic wave equation, as it also encompasses the contribution of shear waves. To reduce the computational cost of wavefield extrapolation in such media, I generate effective isotropic inhomogeneous models that are capable of reproducing the first-arrival kinematic aspects of the orthorhombic wavefield. First, in order to compute traveltimes in vertical orthorhombic media, I develop a stable, efficient and accurate algorithm based on the fast marching method. The derived orthorhombic acoustic dispersion relation, unlike the isotropic or transversely isotropic one, is represented by a sixth order polynomial equation that includes the fastest solution corresponding to outgoing P-waves in acoustic media. The effective velocity models are then computed by evaluating the traveltime gradients of the orthorhombic traveltime solution, which is done by explicitly solving the isotropic eikonal equation for the corresponding inhomogeneous isotropic velocity field. The inverted effective velocity fields are source dependent and produce equivalent first-arrival kinematic descriptions of wave propagation in orthorhombic media. I extrapolate wavefields in these isotropic effective velocity models using the more efficient isotropic operator, and the results compare well, especially kinematically, with those obtained from the

An active one-particle microrheometer: incorporating magnetic tweezers to total internal reflection microscopy.

Science.gov (United States)

Gong, Xiangjun; Hua, Li; Wu, Chi; Ngai, To

2013-03-01

We present a novel microrheometer by incorporating magnetic tweezers in the total internal reflection microscopy (TIRM) that enables measuring of viscoelastic properties of materials near solid surface. An evanescent wave generated by a solid∕liquid interface in the TIRM is used as the incident light source in the microrheometer. When a probe particle (of a few micrometers diameter) moves near the interface, it can interact with the evanescent field and reflect its position with respect to the interface by the scattered light intensity. The exponential distance dependence of the evanescent field, on the one hand, makes this technique extremely sensitive to small changes from z-fluctuations of the probe (with a resolution of several nanometers), and on the other, it does not require imaging of the probe with high lateral resolution. Another distinct advantage is the high sensitivity in determining the z position of the probe in the absence of any labeling. The incorporated magnetic tweezers enable us to effectively manipulate the distance of the embedded particle from the interface either by a constant or an oscillatory force. The force ramp is easy to implement through a coil current ramp. In this way, the local viscous and elastic properties of a given system under different confinements can therefore be measured by resolving the near-surface particle motion. To test the feasibility of applying this microrheology to soft materials, we measured the viscoelastic properties of sucrose and poly(ethylene glycol) solutions and compared the results to bulk rheometry. In addition, we applied this technique in monitoring the structure and properties of deformable microgel particles near the flat surface.

Seismic Imaging, One-Way Wave Equations, Pseudodifferential Operators, Path Integrals, and all that Jazz

Science.gov (United States)

Artoun, Ojenie; David-Rus, Diana; Emmett, Matthew; Fishman, Lou; Fital, Sandra; Hogan, Chad; Lim, Jisun; Lushi, Enkeleida; Marinov, Vesselin

2006-05-01

In this report we summarize an extension of Fourier analysis for the solution of the wave equation with a non-constant coefficient corresponding to an inhomogeneous medium. The underlying physics of the problem is exploited to link pseudodifferential operators and phase space path integrals to obtain a marching algorithm that incorporates the backward scattering into the evolution of the wave. This allows us to successfully apply single-sweep, one-way marching methods in inherently two-way environments, which was not achieved before through other methods for this problem.

Investigation of Wave Transmission from a Floating Wave Dragon Wave Energy Converter

DEFF Research Database (Denmark)

Nørgaard, Jørgen Harck; Andersen, Thomas Lykke

2012-01-01

This paper focuses on the calibration of the MIKE21BW model against the measured wave height reduction behind a 24 kW/m Wave Dragon (WD) wave energy converter. A numerical model is used to determine the wave transmission through the floating WD in varying wave conditions. The transmission obtained...

Understanding the Physical Nature of Coronal "EIT Waves".

Science.gov (United States)

Long, D M; Bloomfield, D S; Chen, P F; Downs, C; Gallagher, P T; Kwon, R-Y; Vanninathan, K; Veronig, A M; Vourlidas, A; Vršnak, B; Warmuth, A; Žic, T

2017-01-01

For almost 20 years the physical nature of globally propagating waves in the solar corona (commonly called "EIT waves") has been controversial and subject to debate. Additional theories have been proposed over the years to explain observations that did not agree with the originally proposed fast-mode wave interpretation. However, the incompatibility of observations made using the Extreme-ultraviolet Imaging Telescope (EIT) onboard the Solar and Heliospheric Observatory with the fast-mode wave interpretation was challenged by differing viewpoints from the twin Solar Terrestrial Relations Observatory spacecraft and data with higher spatial and temporal resolution from the Solar Dynamics Observatory . In this article, we reexamine the theories proposed to explain EIT waves to identify measurable properties and behaviours that can be compared to current and future observations. Most of us conclude that the so-called EIT waves are best described as fast-mode large-amplitude waves or shocks that are initially driven by the impulsive expansion of an erupting coronal mass ejection in the low corona.

Extracorporeal shock wave therapy in periodontics: A new paradigm

Science.gov (United States)

Venkatesh Prabhuji, Munivenkatappa Lakshmaiah; Khaleelahmed, Shaeesta; Vasudevalu, Sujatha; Vinodhini, K.

2014-01-01

The quest for exploring new frontiers in the field of medical science for efficient and improved treatment modalities has always been on a rise. Extracorporeal shock wave therapy (ESWT) has been enormously used in medical practice, principally, for the management of urolithiasis, cholelithiasis and also in various orthopedic and musculoskeletal disorders. The efficacy of ESWT in the stimulation of osteoblasts, fibroblasts, induction of neovascularization and increased expression of bone morphogenic proteins has been well documented in the literature. However, dentistry is no exception to this trend. The present article enlightens the various applications of ESWT in the field of dentistry and explores its prospective applications in the field of periodontics, and the possibility of incorporating the beneficial properties of shock waves in improving the treatment outcome. PMID:25024562

Extracorporeal shock wave therapy in periodontics: A new paradigm

Directory of Open Access Journals (Sweden)

Munivenkatappa Lakshmaiah Venkatesh Prabhuji

2014-01-01

Full Text Available The quest for exploring new frontiers in the field of medical science for efficient and improved treatment modalities has always been on a rise. Extracorporeal shock wave therapy (ESWT has been enormously used in medical practice, principally, for the management of urolithiasis, cholelithiasis and also in various orthopedic and musculoskeletal disorders. The efficacy of ESWT in the stimulation of osteoblasts, fibroblasts, induction of neovascularization and increased expression of bone morphogenic proteins has been well documented in the literature. However, dentistry is no exception to this trend. The present article enlightens the various applications of ESWT in the field of dentistry and explores its prospective applications in the field of periodontics, and the possibility of incorporating the beneficial properties of shock waves in improving the treatment outcome.

A chiral quark model for meson electroproduction in the S11 partial wave

International Nuclear Information System (INIS)

Golli, B.; Sirca, S.

2011-01-01

We calculate the meson scattering and electroproduction amplitudes in the S11 partial wave in a coupled-channel approach that incorporates quasi-bound quark-model states. Using the quark wave functions and the quark-meson interaction from the Cloudy Bag Model, we obtain a good overall agreement with the available experimental results for the partial widths of the N(1535) and the N(1650) resonances as well as for the pion, eta and kaon electroproduction amplitudes. Our model is consistent with the N(1535) resonance being dominantly a genuine three-quark state rather than a quasi-bound state of mesons and baryons. (orig.)

Trend analysis of the wave storminess: the wave direction

Science.gov (United States)

Casas Prat, M.; Sierra, J. P.; Mösso, C.; Sánchez-Arcilla, A.

2009-09-01

directionality. It is based on 44 year hindcast model data (1958-2001) of the HIPOCAS project, enabling to work with a longer time series compared to the existing measured ones. 41 nodes of this database are used, containing 3 hourly simulated data of significant wave height and wave direction, among other parameters. For storm definition, the Peak Over Threshold (POT) method is used with some additional duration requirements in order to analyse statistically independent events (Mendoza & Jiménez, 2006). Including both wave height and storm duration, the wave storminess is characterised by the energy content (Mendoza & Jiménez, 2004), being in turn log-transformed because of its positive scale. Separately, the wave directionality itself is analysed in terms of different sectors and approaching their probability of occurrence by counting events and using Bayesian inference (Agresti, 2002). Therefore, the original data is transformed into compositional data and, before performing the trend analysis, the isometric logratio (ilr) transformation (Egozcue et al., 2003) is done. In general, the trend analysis methodology consists in two steps: 1) trend detection and 2) trend quantification. For 1) the Mann Kendall test is used in order to identify the nodes with significant trend. For these selected nodes, the trend quantification is done, comparing two methods: 1) a simple linear regression analysis complemented with the bootstrap technique and 2) a Bayesian analysis, assuming normally distributed data with linearly increasing mean. Preliminary results show no significant trend for both annual mean and maximum energy content except for some nodes located to the Northern Catalan coast. Regarding the wave direction (but not only considering stormy conditions) there is a tendency of North direction to decrease whereas South and Southeast direction seems to increase.

Coherent Waves in Seismic Researches

Science.gov (United States)

Emanov, A.; Seleznev, V. S.

2013-05-01

reflected waves. With use of developed algorithms of head wave conversion in time sections a work of studying of refracting boundaries in Siberia have been executed. Except for the research by method of refracting waves, the conversion of head waves in time sections, applied to seismograms of reflected wave method, allows to obtain information about refracting horizons in upper part of section in addition to reflecting horizons data. Recovery method of wave field coherent components is the basis of the engineering seismology on the level of accuracy and detail. In seismic microzoning resonance frequency of the upper part of section are determined on the basis of this method. Maps of oscillation amplification and result accuracy are constructed for each of the frequencies. The same method makes it possible to study standing wave field in buildings and constructions with high accuracy and detail, realizing diagnostics of their physical state on set of natural frequencies and form of self-oscillations, examined with high detail. The method of standing waves permits to estimate a seismic stability of structure on new accuracy level.

A case study of the energy dissipation of the gravity wave field based on satellite altimeter measurements

Science.gov (United States)

Huang, N. E.; Parsons, C. L.; Long, S. R.; Bliven, L. F.

1983-01-01

Wave breaking is proposed as the primary energy dissipation mechanism for the gravity wave field. The energy dissipation rate is calculated based on the statistical model proposed by Longuet-Higgins (1969) with a modification of the breaking criterion incorporating the surface stress according to Phillips and Banner (1974). From this modified model, an analytic expression is found for the wave attenuation rate and the half-life time of the wave field which depend only on the significant slope of the wave field and the ratio of friction velocity to initial wave phase velocity. These expressions explain why the freshly generated wave field does not last long, but why swells are capable of propagating long distances without substantial change in energy density. It is shown that breaking is many orders of magnitude more effective in dissipating wave energy than the molecular viscosity, if the significant slope is higher than 0.01. Limited observational data from satellite and laboratory are used to compare with the analytic results, and show good agreement.

Resonant Wave Energy Converters: Small-scale field experiments and first full-scale prototype

International Nuclear Information System (INIS)

Arena, Felice; Fiamma, Vincenzo; Iannolo, Roberto; Laface, Valentina; Malara, Giovanni; Romolo, Alessandra; Strati Federica Maria

2015-01-01

The Resonant Wave Energy Converter 3 (REWEC3) is a device belonging to the family of Oscillating Water Columns (OWCs), that can convert the energy of incident waves into electrical energy via turbines. In contrast to classical OWCs, it incorporates a small vertical U-shaped duct to connect the water column to the open wave field. This article shows the results of a small-scale field experiment involving a REWEC3 designed for working with a 2 kW turbine. Then, the next experimental activity on a REWEC3 installed in the NOEL laboratory with the collaboration of ENEA, is presented. Finally, the first prototype of ReWEC3 under construction in Civitavecchia (Rome, Italy) is shown. The crucial features of the construction stage are discussed and some initial performances are provided. [it

Ultrasonic guided wave for monitoring corrosion of steel bar

Science.gov (United States)

Liu, Xi; Qin, Lei; Huang, Bosheng

2018-01-01

Steel corrosion of reinforced concrete structures has become a serious problem all over the word. In this paper, the work aims at monitoring steel corrosion using ultrasonic guided wave (UGW). Ultrasonic guided wave monitoring is a dynamic and non-destructive testing technology. The advantages of ultrasonic guided wave monitoring for reinforcement corrosion are real-time, online and continuous. In addition, it can judge the different stages of steel bar corrosion, which achieved non-destructive detection.

Wave Equation Inversion of Skeletonized SurfaceWaves

KAUST Repository

Zhang, Zhendong

2015-08-19

We present a surface-wave inversion method that inverts for the S-wave velocity from the Rayleigh dispersion curve for the fundamental-mode. We call this wave equation inversion of skeletonized surface waves because the dispersion curve for the fundamental-mode Rayleigh wave is inverted using finite-difference solutions to the wave equation. The best match between the predicted and observed dispersion curves provides the optimal S-wave velocity model. Results with synthetic and field data illustrate the benefits and limitations of this method.

Harnessing Alternative Energy Sources to Enhance the Design of a Wave Generator

Science.gov (United States)

Bravo, A.

2017-12-01

Wave energy has the power to replace a non-renewable source of electricity for a home near the ocean. I built a small-scale wave generator capable of producing approximately 5 volts of electricity. The generator is an array of 16 small generators, each consisting of 200 feet of copper wire, 12 magnets, and a buoy. I tested my design in the Pacific Ocean and was able to power a string of lights I had attached to the generator. While the waves in the ocean moved my buoys, my design was powered by the vertical motion of the waves. My generator was hit with significant horizontal wave motion, and I realized I wasn't taking advantage of that direction of motion. To make my generator produce more electricity, I experimented with capturing the energy of the horizontal motion of water and incorporated that into my generator design. My generator, installed in the ocean, is also exposed to sun and wind, and I am exploring the potential of solar and wind energy collection in my design to increase the electricity output. Once I have maximized my electricity output, I would like to explore scaling up my design.

Prediction of regular wave loads on a fixed offshore oscillating water column-wave energy converter using CFD

Directory of Open Access Journals (Sweden)

Ahmed Elhanafi

2016-12-01

Full Text Available In this paper, hydrodynamic wave loads on an offshore stationary–floating oscillating water column (OWC are investigated via a 2D and 3D computational fluid dynamics (CFD modeling based on the RANS equations and the VOF surface capturing scheme. The CFD model is validated against previous experiments for nonlinear regular wave interactions with a surface-piercing stationary barge. Following the validation stage, the numerical model is modified to consider the pneumatic damping effect, and an extensive campaign of numerical tests is carried out to study the wave–OWC interactions for different wave periods, wave heights and pneumatic damping factors. It is found that the horizontal wave force is usually larger than the vertical one. Also, there a direct relationship between the pneumatic and hydrodynamic vertical forces with a maximum vertical force almost at the device natural frequency, whereas the pneumatic damping has a little effect on the horizontal force. Additionally, simulating the turbine damping with an orifice plate induces higher vertical loads than utilizing a slot opening. Furthermore, 3D modeling significantly escalates and declines the predicted hydrodynamic vertical and horizontal wave loads, respectively.

Blocking of indium incorporation by antimony in III-V-Sb nanostructures

International Nuclear Information System (INIS)

Sanchez, A M; Beltran, A M; Ben, T; Molina, S I; Beanland, R; Gass, M H; De la Pena, F; Walls, M; Taboada, A G; Ripalda, J M

2010-01-01

The addition of antimony to III-V nanostructures is expected to give greater freedom in bandgap engineering for device applications. One of the main challenges to overcome is the effect of indium and antimony surface segregation. Using several very high resolution analysis techniques we clearly demonstrate blocking of indium incorporation by antimony. Furthermore, indium incorporation resumes when the antimony concentration drops below a critical level. This leads to major differences between nominal and actual structures.

Terahertz-wave near-field imaging with subwavelength resolution using surface-wave-assisted bow-tie aperture

Science.gov (United States)

Ishihara, Kunihiko; Ohashi, Keishi; Ikari, Tomofumi; Minamide, Hiroaki; Yokoyama, Hiroyuki; Shikata, Jun-ichi; Ito, Hiromasa

2006-11-01

We demonstrate the terahertz-wave near-field imaging with subwavelength resolution using a bow-tie shaped aperture surrounded by concentric periodic structures in a metal film. A subwavelength aperture with concentric periodic grooves, which are known as a bull's eye structure, shows extremely large enhanced transmission beyond the diffraction limit caused by the resonant excitation of surface waves. Additionally, a bow-tie aperture exhibits extraordinary field enhancement at the sharp tips of the metal, which enhances the transmission and the subwavelength spatial resolution. We introduced a bow-tie aperture to the bull's eye structure and achieved high spatial resolution (˜λ/17) in the near-field region. The terahertz-wave near-field image of the subwavelength metal pattern (pattern width=20μm) was obtained for the wavelength of 207μm.

Efficient Wave Energy Amplification with Wave Reflectors

DEFF Research Database (Denmark)

Kramer, Morten Mejlhede; Frigaard, Peter Bak

2002-01-01

Wave Energy Converters (WEC's) extract wave energy from a limited area, often a single point or line even though the wave energy is generally spread out along the wave crest. By the use of wave reflectors (reflecting walls) the wave energy is effectively focused and increased to approximately 130......-140%. In the paper a procedure for calculating the efficiency and optimizing the geometry of wave reflectors are described, this by use of a 3D boundary element method. The calculations are verified by laboratory experiments and a very good agreement is found. The paper gives estimates of possible power benifit...... for different geometries of the wave reflectors and optimal geometrical design parameters are specified. On this basis inventors of WEC's can evaluate whether a specific WEC possible could benefit from wave reflectors....

Phenomenological effets of tantalum incorporation into diamond films: Experimental and first principle studies

Energy Technology Data Exchange (ETDEWEB)

Ullah, Mahtab, E-mail: mahtabullah@bzu.edu.pk [Department of Physics, Bahauddin Zakariya University Multan (Pakistan); Rana, Anwar Manzoor; Ahmad, E. [Department of Physics, Bahauddin Zakariya University Multan (Pakistan); Raza, Rizwan [Department of Physics, COMSATS Institute of Information Technology, Lahore-54000 (Pakistan); Hussain, Fayyaz [Department of Physics, Bahauddin Zakariya University Multan (Pakistan); Hussain, Akhtar; Iqbal, Muhammad [Theoretical Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan)

2016-09-01

Graphical abstract: - Highlights: • Fabrication of tantalum incorporated diamonds films using HFCVD technique. • Decrease in resistivity by increasing tantalum content in diamond thin films. • Electronic structure calculations of tantalum incorporated diamonds films through VASP code. • A rise of bond length and bond angles by addition of tantalum in the diamond lattice. • Confirmation of decrease of resistivity by adding tantalum due to creation of impurity states in the bandgap. - Abstract: Tantalum (Ta) incorporated diamond films are synthesized on silicon substrate by chemical vapor deposition under gas mixture of CH{sub 4} + H{sub 2}. Characterizations of the resulting films indicate that morphology and resistivity of as-grown diamond films are significantly influenced by the process parameters and the amount of tantalum incorporated in the diamond films. XRD plots reveal that diamond films are composed of TaC along with diamond for higher concentration of tantalum and Ta{sub 2}C phases for lower concentration of tantalum. EDS spectra confirms the existence of tantalum in the diamond films. Resistivity measurements illustrate a sudden fall of about two orders of magnitude by the addition of tantalum in the diamond films. Band structure of Ta-incorporated diamond has been investigated based on density functional theory (DFT) using VASP code. Band structure calculations lead to the semiconducting behavior of Ta-incorporated diamond films because of the creation of defects states inside the band gap extending towards conduction band minimum. Present DFT results support experimental trend of resistivity that with the incorporation of tantalum into diamond lattice causes a decrease in the resistivity of diamond films so that tantalum-incorporated diamond films behave like a good semiconductor.

High field side launch of RF waves: A new approach to reactor actuators

Science.gov (United States)

Wallace, G. M.; Baek, S. G.; Bonoli, P. T.; Faust, I. C.; LaBombard, B. L.; Lin, Y.; Mumgaard, R. T.; Parker, R. R.; Shiraiwa, S.; Vieira, R.; Whyte, D. G.; Wukitch, S. J.

2015-12-01

Launching radio frequency (RF) waves from the high field side (HFS) of a tokamak offers significant advantages over low field side (LFS) launch with respect to both wave physics and plasma material interactions (PMI). For lower hybrid (LH) waves, the higher magnetic field opens the window between wave accessibility (n∥≡c k∥/ω >√{1 -ωpi 2/ω2+ωpe 2/ωce 2 }+ωp e/|ωc e| ) and the condition for strong electron Landau damping (n∥˜√{30 /Te } with Te in keV), allowing LH waves from the HFS to penetrate into the core of a burning plasma, while waves launched from the LFS are restricted to the periphery of the plasma. The lower n∥ of waves absorbed at higher Te yields a higher current drive efficiency as well. In the ion cyclotron range of frequencies (ICRF), HFS launch allows for direct access to the mode conversion layer where mode converted waves absorb strongly on thermal electrons and ions, thus avoiding the generation of energetic minority ion tails. The absence of turbulent heat and particle fluxes on the HFS, particularly in double null configuration, makes it the ideal location to minimize PMI damage to the antenna structure. The quiescent SOL also eliminates the need to couple LH waves across a long distance to the separatrix, as the antenna can be located close to plasma without risking damage to the structure. Improved impurity screening on the HFS will help eliminate the long-standing issues of high Z impurity accumulation with ICRF. Looking toward a fusion reactor, the HFS is the only possible location for a plasma-facing RF antenna that will survive long-term. By integrating the antenna into the blanket module it is possible to improve the tritium breeding ratio compared with an antenna occupying an equatorial port plug. Blanket modules will require remote handling of numerous cooling pipes and electrical connections, and the addition of transmission lines will not substantially increase the level of complexity. The obvious engineering

Identifying coronary artery disease in asymptomatic middle-aged sportsmen : The additional value of pulse wave velocity

NARCIS (Netherlands)

Braber, Thijs L.; Prakken, Niek H J; Mosterd, Arend; Mali, Willem P Th M; Doevendans, Pieter A F M; Bots, Michiel L.; Velthuis, Birgitta K.

2015-01-01

Background: Cardiovascular screening may benefit middle-aged sportsmen, as coronary artery disease (CAD) is the main cause of exercise-related sudden cardiac death. Arterial stiffness, as measured by pulse wave velocity (PWV), may help identify sportsmen with subclinical CAD. We examined the

Assimilation of Wave Imaging Radar Observations for Real-Time Wave-by-Wave Forecasting

Science.gov (United States)

Haller, M. C.; Simpson, A. J.; Walker, D. T.; Lynett, P. J.; Pittman, R.; Honegger, D.

2016-02-01

It has been shown in various studies that a controls system can dramatically improve Wave Energy Converter (WEC) power production by tuning the device's oscillations to the incoming wave field, as well as protect WEC devices by decoupling them in extreme wave conditions. A requirement of the most efficient controls systems is a phase-resolved, "deterministic" surface elevation profile, alerting the device to what it will experience in the near future. The current study aims to demonstrate a deterministic method of wave forecasting through the pairing of an X-Band marine radar with a predictive Mild Slope Equation (MSE) wave model. Using the radar as a remote sensing technique, the wave field up to 1-4 km surrounding a WEC device can be resolved. Individual waves within the radar scan are imaged through the contrast between high intensity wave faces and low intensity wave troughs. Using a recently developed method, radar images are inverted into the radial component of surface slope, shown in the figure provided using radar data from Newport, Oregon. Then, resolved radial slope images are assimilated into the MSE wave model. This leads to a best-fit model hindcast of the waves within the domain. The hindcast is utilized as an initial condition for wave-by-wave forecasting with a target forecast horizon of 3-5 minutes (tens of wave periods). The methodology is currently being tested with synthetic data and comparisons with field data are imminent.

The integration of elastic wave properties and machine learning for the distribution of petrophysical properties in reservoir modeling

Science.gov (United States)

Ratnam, T. C.; Ghosh, D. P.; Negash, B. M.

2018-05-01

Conventional reservoir modeling employs variograms to predict the spatial distribution of petrophysical properties. This study aims to improve property distribution by incorporating elastic wave properties. In this study, elastic wave properties obtained from seismic inversion are used as input for an artificial neural network to predict neutron porosity in between well locations. The method employed in this study is supervised learning based on available well logs. This method converts every seismic trace into a pseudo-well log, hence reducing the uncertainty between well locations. By incorporating the seismic response, the reliance on geostatistical methods such as variograms for the distribution of petrophysical properties is reduced drastically. The results of the artificial neural network show good correlation with the neutron porosity log which gives confidence for spatial prediction in areas where well logs are not available.

Microcontroller based automatic liquid poison addition control system

International Nuclear Information System (INIS)

Kapatral, R.S.; Ananthakrishnan, T.S.; Pansare, M.G.

1989-01-01

Microcontrollers are finding increasing applications in instrumentation where complex digital circuits can be substituted by a compact and simple circuit, thus enhancing the reliability. In addition to this, intelligence and flexibility can be incorporated. For applications not requiring large amount of read/write memory (RAM), microcontrollers are ideally suited since they contain programmable memory (Eprom), parallel input/output lines, data memory, programmable timers and serial interface ports in one chip. This paper describes the design of automatic liquid poison addition control system (ALPAS) using intel's 8 bit microcontroller 8751, which is used to generate complex timing control sequence signals for liquid poison addition to the moderator in a nuclear reactor. ALPAS monitors digital inputs coming from protection system and regulating system of a nuclear reactor and provides control signals for liquid poison addition for long term safe shutdown of the reactor after reactor trip and helps the regulating system to reduce the power of the reactor during operation. Special hardware and software features have been incorporated to improve performance and fault detection. (author)

Traveling-Wave Maser for 32 GHz

Science.gov (United States)

Shell, James; Clauss, Robert

2009-01-01

The figure depicts a traveling-wave ruby maser that has been designed (though not yet implemented in hardware) to serve as a low-noise amplifier for reception of weak radio signals in the frequency band of 31.8 to 32.3 GHz. The design offers significant improvements over previous designs of 32-GHz traveling-wave masers. In addition, relative to prior designs of 32-GHz amplifiers based on high-electron-mobility transistors, this design affords higher immunity to radio-frequency interference and lower equivalent input noise temperature. In addition to the basic frequency-band and low-noise requirements, the initial design problem included a requirement for capability of operation in a closed-cycle helium refrigerator at a temperature .4 K and a requirement that the design be mechanically simplified, relative to prior designs, in order to minimize the cost of fabrication and assembly. Previous attempts to build 32- GHz traveling-wave masers involved the use of metallic slow-wave structures comprising coupled transverse electromagnetic (TEM)-mode resonators that were subject to very tight tolerances and, hence, were expensive to fabricate and assemble. Impedance matching for coupling signals into and out of these earlier masers was very difficult. A key feature of the design is a slow-wave structure, the metallic portions of which would be mechanically relatively simple in that, unlike in prior slow-wave structures, there would be no internal metal steps, irises, or posts. The metallic portions of the slow-wave structure would consist only of two rectangular metal waveguide arms. The arms would contain sections filled with the active material (ruby) alternating with evanescent-wave sections. This structure would be transparent in both the signal-frequency band (the aforementioned range of 31.8 to 32.3 GHz) and the pump-frequency band (65.75 to 66.75 GHz), and would impose large slowing factors in both frequency bands. Resonant ferrite isolators would be placed in the

Waves in geophysical fluids tsunamis, rogue waves, internal waves and internal tides

CERN Document Server

Schneider, Wilhelm; Trulsen, Karsten

2006-01-01

Waves in Geophysical Fluids describes: the forecasting and risk evaluation of tsunamis by tectonic motion, land slides, explosions, run-up, and maps the tsunami sources in the world's oceans; stochastic Monte-Carlo simulations and focusing mechanisms for rogue waves, nonlinear wave models, breather formulas, and the kinematics of the Draupner wave; the full story about the discovery of the very large oceanic internal waves, how the waves are visible from above through the signatures on the sea surface, and how to compute them; observations of energetic internal tides and hot spots from several field campaigns in all parts of the world's oceans, with interpretation of spectra. An essential work for students, scientists and engineers working with the fundamental and applied aspects of ocean waves.

Parameterization of planetary wave breaking in the middle atmosphere

Science.gov (United States)

Garcia, Rolando R.

1991-01-01

A parameterization of planetary wave breaking in the middle atmosphere has been developed and tested in a numerical model which includes governing equations for a single wave and the zonal-mean state. The parameterization is based on the assumption that wave breaking represents a steady-state equilibrium between the flux of wave activity and its dissipation by nonlinear processes, and that the latter can be represented as linear damping of the primary wave. With this and the additional assumption that the effect of breaking is to prevent further amplitude growth, the required dissipation rate is readily obtained from the steady-state equation for wave activity; diffusivity coefficients then follow from the dissipation rate. The assumptions made in the derivation are equivalent to those commonly used in parameterizations for gravity wave breaking, but the formulation in terms of wave activity helps highlight the central role of the wave group velocity in determining the dissipation rate. Comparison of model results with nonlinear calculations of wave breaking and with diagnostic determinations of stratospheric diffusion coefficients reveals remarkably good agreement, and suggests that the parameterization could be useful for simulating inexpensively, but realistically, the effects of planetary wave transport.

Alfvén Wave Turbulence as a Coronal Heating Mechanism: Simultaneously Predicting the Heating Rate and the Wave-induced Emission Line Broadening

Energy Technology Data Exchange (ETDEWEB)

Oran, R. [Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139 (United States); Landi, E.; Holst, B. van der; Sokolov, I. V.; Gombosi, T. I., E-mail: roran@mit.edu [Atmospheric, Oceanic and Atmospheric Sciences, University of Michigan, 2455 Hayward, Ann Arbor, MI, 48109 (United States)

2017-08-20

We test the predictions of the Alfvén Wave Solar Model (AWSoM), a global wave-driven magnetohydrodynamic (MHD) model of the solar atmosphere, against high-resolution spectra emitted by the quiescent off-disk solar corona. AWSoM incorporates Alfvén wave propagation and dissipation in both closed and open magnetic field lines; turbulent dissipation is the only heating mechanism. We examine whether this mechanism is consistent with observations of coronal EUV emission by combining model results with the CHIANTI atomic database to create synthetic line-of-sight spectra, where spectral line widths depend on thermal and wave-related ion motions. This is the first time wave-induced line broadening is calculated from a global model with a realistic magnetic field. We used high-resolution SUMER observations above the solar west limb between 1.04 and 1.34 R {sub ⊙} at the equator, taken in 1996 November. We obtained an AWSoM steady-state solution for the corresponding period using a synoptic magnetogram. The 3D solution revealed a pseudo-streamer structure transversing the SUMER line of sight, which contributes significantly to the emission; the modeled electron temperature and density in the pseudo-streamer are consistent with those observed. The synthetic line widths and the total line fluxes are consistent with the observations for five different ions. Further, line widths that include the contribution from the wave-induced ion motions improve the correspondence with observed spectra for all ions. We conclude that the turbulent dissipation assumed in the AWSoM model is a viable candidate for explaining coronal heating, as it is consistent with several independent measured quantities.

The thin section rock physics: Modeling and measurement of seismic wave velocity on the slice of carbonates

Energy Technology Data Exchange (ETDEWEB)

Wardaya, P. D., E-mail: pongga.wardaya@utp.edu.my; Noh, K. A. B. M., E-mail: pongga.wardaya@utp.edu.my; Yusoff, W. I. B. W., E-mail: pongga.wardaya@utp.edu.my [Petroleum Geosciences Department, Universiti Teknologi PETRONAS, Tronoh, Perak, 31750 (Malaysia); Ridha, S. [Petroleum Engineering Department, Universiti Teknologi PETRONAS, Tronoh, Perak, 31750 (Malaysia); Nurhandoko, B. E. B. [Wave Inversion and Subsurface Fluid Imaging Research Laboratory (WISFIR), Dept. of Physics, Institute of Technology Bandung, Bandung, Indonesia and Rock Fluid Imaging Lab, Bandung (Indonesia)

2014-09-25

This paper discusses a new approach for investigating the seismic wave velocity of rock, specifically carbonates, as affected by their pore structures. While the conventional routine of seismic velocity measurement highly depends on the extensive laboratory experiment, the proposed approach utilizes the digital rock physics view which lies on the numerical experiment. Thus, instead of using core sample, we use the thin section image of carbonate rock to measure the effective seismic wave velocity when travelling on it. In the numerical experiment, thin section images act as the medium on which wave propagation will be simulated. For the modeling, an advanced technique based on artificial neural network was employed for building the velocity and density profile, replacing image's RGB pixel value with the seismic velocity and density of each rock constituent. Then, ultrasonic wave was simulated to propagate in the thin section image by using finite difference time domain method, based on assumption of an acoustic-isotropic medium. Effective velocities were drawn from the recorded signal and being compared to the velocity modeling from Wyllie time average model and Kuster-Toksoz rock physics model. To perform the modeling, image analysis routines were undertaken for quantifying the pore aspect ratio that is assumed to represent the rocks pore structure. In addition, porosity and mineral fraction required for velocity modeling were also quantified by using integrated neural network and image analysis technique. It was found that the Kuster-Toksoz gives the closer prediction to the measured velocity as compared to the Wyllie time average model. We also conclude that Wyllie time average that does not incorporate the pore structure parameter deviates significantly for samples having more than 40% porosity. Utilizing this approach we found a good agreement between numerical experiment and theoretically derived rock physics model for estimating the effective seismic

The thin section rock physics: Modeling and measurement of seismic wave velocity on the slice of carbonates

International Nuclear Information System (INIS)

Wardaya, P. D.; Noh, K. A. B. M.; Yusoff, W. I. B. W.; Ridha, S.; Nurhandoko, B. E. B.

2014-01-01

This paper discusses a new approach for investigating the seismic wave velocity of rock, specifically carbonates, as affected by their pore structures. While the conventional routine of seismic velocity measurement highly depends on the extensive laboratory experiment, the proposed approach utilizes the digital rock physics view which lies on the numerical experiment. Thus, instead of using core sample, we use the thin section image of carbonate rock to measure the effective seismic wave velocity when travelling on it. In the numerical experiment, thin section images act as the medium on which wave propagation will be simulated. For the modeling, an advanced technique based on artificial neural network was employed for building the velocity and density profile, replacing image's RGB pixel value with the seismic velocity and density of each rock constituent. Then, ultrasonic wave was simulated to propagate in the thin section image by using finite difference time domain method, based on assumption of an acoustic-isotropic medium. Effective velocities were drawn from the recorded signal and being compared to the velocity modeling from Wyllie time average model and Kuster-Toksoz rock physics model. To perform the modeling, image analysis routines were undertaken for quantifying the pore aspect ratio that is assumed to represent the rocks pore structure. In addition, porosity and mineral fraction required for velocity modeling were also quantified by using integrated neural network and image analysis technique. It was found that the Kuster-Toksoz gives the closer prediction to the measured velocity as compared to the Wyllie time average model. We also conclude that Wyllie time average that does not incorporate the pore structure parameter deviates significantly for samples having more than 40% porosity. Utilizing this approach we found a good agreement between numerical experiment and theoretically derived rock physics model for estimating the effective seismic wave

Blast effects physical properties of shock waves

CERN Document Server

2018-01-01

This book compiles a variety of experimental data on blast waves. The book begins with an introductory chapter and proceeds to the topic of blast wave phenomenology, with a discussion Rankine-Hugoniot equations and the Friedlander equation, used to describe the pressure-time history of a blast wave. Additional topics include arrival time measurement, the initiation of detonation by exploding wires, a discussion of TNT equivalency, and small scale experiments. Gaseous and high explosive detonations are covered as well. The topics and experiments covered were chosen based on the comparison of used scale sizes, from small to large. Each characteristic parameter of blast waves is analyzed and expressed versus scaled distance in terms of energy and mass. Finally, the appendix compiles a number of polynomial laws that will prove indispensable for engineers and researchers.

Photoelectron wave function in photoionization: plane wave or Coulomb wave?

Science.gov (United States)

Gozem, Samer; Gunina, Anastasia O; Ichino, Takatoshi; Osborn, David L; Stanton, John F; Krylov, Anna I

2015-11-19

The calculation of absolute total cross sections requires accurate wave functions of the photoelectron and of the initial and final states of the system. The essential information contained in the latter two can be condensed into a Dyson orbital. We employ correlated Dyson orbitals and test approximate treatments of the photoelectron wave function, that is, plane and Coulomb waves, by comparing computed and experimental photoionization and photodetachment spectra. We find that in anions, a plane wave treatment of the photoelectron provides a good description of photodetachment spectra. For photoionization of neutral atoms or molecules with one heavy atom, the photoelectron wave function must be treated as a Coulomb wave to account for the interaction of the photoelectron with the +1 charge of the ionized core. For larger molecules, the best agreement with experiment is often achieved by using a Coulomb wave with a partial (effective) charge smaller than unity. This likely derives from the fact that the effective charge at the centroid of the Dyson orbital, which serves as the origin of the spherical wave expansion, is smaller than the total charge of a polyatomic cation. The results suggest that accurate molecular photoionization cross sections can be computed with a modified central potential model that accounts for the nonspherical charge distribution of the core by adjusting the charge in the center of the expansion.

Effect of long-wave ultraviolet light on the lens. I. Model systems for detecting and measuring effect on the lens in vitro

International Nuclear Information System (INIS)

Kuck, J.F.R. Jr.

1976-01-01

Rat, mouse, and chick lenses incubated with 3-aminotriazole under long-wave ultraviolet (UV) show reduced accumulation and incorporation of leucine and a loss of glutathione. The effect on leucine incorporation is strikingly enhanced when capsule-epithelium pools are incubated. The procedure may identify photosensitizers or metabolic inhibitors which are cataractogenic when acting in conjunction with UV

Leading Wave Amplitude of a Tsunami

Science.gov (United States)

Kanoglu, U.

2015-12-01

Okal and Synolakis (EGU General Assembly 2015, Geophysical Research Abstracts-Vol. 17-7622) recently discussed that why the maximum amplitude of a tsunami might not occur for the first wave. Okal and Synolakis list observations from 2011 Japan tsunami, which reached to Papeete, Tahiti with a fourth wave being largest and 72 min later after the first wave; 1960 Chilean tsunami reached Hilo, Hawaii with a maximum wave arriving 1 hour later with a height of 5m, first wave being only 1.2m. Largest later waves is a problem not only for local authorities both in terms of warning to the public and rescue efforts but also mislead the public thinking that it is safe to return shoreline or evacuated site after arrival of the first wave. Okal and Synolakis considered Hammack's (1972, Ph.D. Dissertation, Calif. Inst. Tech., 261 pp., Pasadena) linear dispersive analytical solution with a tsunami generation through an uplifting of a circular plug on the ocean floor. They performed parametric study for the radius of the plug and the depth of the ocean since these are the independent scaling lengths in the problem. They identified transition distance, as the second wave being larger, regarding the parameters of the problem. Here, we extend their analysis to an initial wave field with a finite crest length and, in addition, to a most common tsunami initial wave form of N-wave as presented by Tadepalli and Synolakis (1994, Proc. R. Soc. A: Math. Phys. Eng. Sci., 445, 99-112). We compare our results with non-dispersive linear shallow water wave results as presented by Kanoglu et al. (2013, Proc. R. Soc. A: Math. Phys. Eng. Sci., 469, 20130015), investigating focusing feature. We discuss the results both in terms of leading wave amplitude and tsunami focusing. Acknowledgment: The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no 603839 (Project ASTARTE - Assessment, Strategy and Risk

The role of localised Ultra-Low Frequency waves in energetic electron precipitation

Science.gov (United States)

Rae, J.; Murphy, K. R.; Watt, C.; Mann, I. R.; Ozeke, L.; Halford, A. J.; Sibeck, D. G.; Clilverd, M. A.; Rodger, C. J.; Degeling, A. W.; Singer, H. J.

2016-12-01

Electromagnetic waves play pivotal roles in radiation belt dynamics through a variety of different means. Typically, Ultra-Low Frequency (ULF) waves have historically been invoked for radial diffusive transport leading to both acceleration and loss of outer radiation belt electrons. Very-Low Frequency (VLF) and Extremely-Low Frequency (ELF) waves are generally thought to provide a mechanism for localized acceleration and loss through precipitation into the ionosphere. In this study we present a new mechanism for electron loss through precipitation into the ionosphere due to direct modulation of the loss cone via localized compressional ULF waves. Observational evidence is presented demonstrating that modulation of the equatorial loss cone can occur via localized compressional wave activity. We then perform statistical computations of the probability distribution to determine how likely a given magnetic perturbation would produce a given percentage change in the bounce loss-cone (BLC). We discuss the ramifications of the action of coherent, localized compressional ULF waves on drifting electron populations; their precipitation response can be a complex interplay between electron energy, the shape of the phase space density profile at pitch angles close to the loss cone, ionospheric decay timescales, and the time-dependence of the electron source. We present a case study of compressional wave activity in tandem with riometer and balloon-borne electron precipitation across keV-MeV energies to demonstrate that the experimental measurements can be explained by our new enhanced loss cone mechanism. We determine that the two pivotal components not usually considered are localized ULF wave fields and ionospheric decay timescales. We conclude that ULF wave modulation of the loss cone is a viable candidate for direct precipitation of radiation belt electrons without any additional requirement for gyroresonant wave-particle interaction. Additional mechanisms would be

Research activities and plan of electron cyclotron wave startup and Alfven wave current drive at SUNIST

International Nuclear Information System (INIS)

Gao Zhe; He Yexi; Tan Yi

2009-01-01

Using electromagnetic waves to startup and sustain plasma current takes a important role in the research program of the SUNIST spherical tokamak. Electron cyclotron ware (ECW) current startup have been investigated and revealed two totally different regimes. In the regime of very low working pressure, a plasma current of about 2 kA is obtained with a steadily applied vertical field of 12 Gauss and 40 kW/2.45 GHz microwave injection. In addition, the physics of the transient process during ECW startup in the relatively high working pressure regime is analyzed. The hardware preparation for the experimental research of Alfven wave current drive is being performed. The Alfven wave antenna system consists of four models in toroidal direction and two antenna straps in poloidal direction for each module and the rf generator has been designed as a four-phase oscillator (4x100 kW, 0.5 - 1 Mhz).The impedance spectrum of the antenna system is roughly evaluated by 1-D cylindrical magneto-hydrodynamic calculation. To investigate the wave-plasma interaction in ECW startup and Alfven wave current drive, upgrade of the device, especially in equilibrium control and diagnostics, is ongoing. (author)

Second harmonic electromagnetic emission via Langmuir wave coalescence

International Nuclear Information System (INIS)

Willes, A.J.; Robinson, P.A.; Melrose, D.B.

1996-01-01

The coalescence of Langmuir waves to produce electromagnetic waves at twice the plasma frequency is considered. A simplified expression for the rate of production of second harmonic electromagnetic waves is obtained for a broad class of Langmuir spectra. In addition, two different analytic approximations are considered. The validity of the commonly used head-on approximation is explored, in which the two coalescing Langmuir waves are assumed to approach from opposite directions. This approximation breaks down at low Langmuir wavenumbers, and for narrow Langmuir wave spectra. A second, more general, approximation is introduced, called the narrow-spectrum approximation, which requires narrow spectral widths of the Langmuir spectra. The advantages of this approximation are that it does not break down at low Langmuir wavenumbers, and that it remains valid for relatively broad Langmuir wave spectra. Finally, the applicability of these approximations in treating harmonic radiation in type III solar radio bursts is discussed. copyright 1996 American Institute of Physics

Critical point anomalies include expansion shock waves

Energy Technology Data Exchange (ETDEWEB)

Nannan, N. R., E-mail: ryan.nannan@uvs.edu [Mechanical Engineering Discipline, Anton de Kom University of Suriname, Leysweg 86, PO Box 9212, Paramaribo, Suriname and Process and Energy Department, Delft University of Technology, Leeghwaterstraat 44, 2628 CA Delft (Netherlands); Guardone, A., E-mail: alberto.guardone@polimi.it [Department of Aerospace Science and Technology, Politecnico di Milano, Via La Masa 34, 20156 Milano (Italy); Colonna, P., E-mail: p.colonna@tudelft.nl [Propulsion and Power, Delft University of Technology, Kluyverweg 1, 2629 HS Delft (Netherlands)

2014-02-15

From first-principle fluid dynamics, complemented by a rigorous state equation accounting for critical anomalies, we discovered that expansion shock waves may occur in the vicinity of the liquid-vapor critical point in the two-phase region. Due to universality of near-critical thermodynamics, the result is valid for any common pure fluid in which molecular interactions are only short-range, namely, for so-called 3-dimensional Ising-like systems, and under the assumption of thermodynamic equilibrium. In addition to rarefaction shock waves, diverse non-classical effects are admissible, including composite compressive shock-fan-shock waves, due to the change of sign of the fundamental derivative of gasdynamics.

Optimization of microwave heating in an existing cubicle cavity by incorporating additional wave guide and control components

International Nuclear Information System (INIS)

Erle, R.R.; Eschen, V.G.; Sprenger, G.S.

1995-04-01

The use of microwave energy to thermally treat Low Level (LLW), Transuranic (TRU), and mixed waste has been under development at the Rocky Flats Environmental Technology Site (Site) since 1986. During that time, the technology has progressed from bench-scale tests, through pilot-scale tests, and finally to a full-scale demonstration unit. Experimental operations have been conducted on a variety of non-radioactive surrogates and actual radioactive waste forms. Through these studies and development efforts, the Microwave Vitrification Engineering Team (MVET) at Rocky Flats has successfully proven the application of microwave energy for waste treatment operations. In the microwave solidification process, microwave energy is used to heat a mixture of waste and glass frit to produce a vitrified product that meets all the current acceptance criteria at the final disposal sites. All of the development to date has utilized a multi-mode microwave system to provide the energy to treat the materials. Currently, evaluations are underway on modifications to the full-scale demonstration system that provide a single-mode operation as a possible method to optimize the system. This poster presentation describes the modifications made to allow the single-mode operation

MHD waves, reconnection, and plasma transport at the dayside magnetopause

International Nuclear Information System (INIS)

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

1996-01-01

The magnetic field of the Earth creates a huge cavity in the solar wind known as the magnetosphere. The transition region between the solar wind plasma and magnetosphere plasma is of substantial interest because many magnetospheric processes are governed by the transport of particles, momentum and energy across that boundary. At this boundary, the magnetopause, there is an abrupt decrease in plasma bulk flow, density and pressure, and large increase in temperature and magnetic field. Throughout this region the plasmas is large. Large amplitude compressional waves are nearly always found in the region just outside of the magnetopause. These waves are either intrinsic solar wind fluctuations or they may be global mirror modes which are generated in a localized region of large pressure anisotropy just outside the magnetopause. The substantial background gradients observed at the magnetopause strongly couple the compressional waves with kinetic Alfven waves near the Alfven resonance location, leading to substantial particle transport. Moreover, for a sheared background magnetic field, as is found at times of southward interplanetary magnetic field, the mode converted kinetic Alfven waves can propagate to the location where k parallel = 0 and generate islands in phase space. We present a solution of the kinetic-MHD wave equations for the magnetic field structure based on a realistic steady state profile which includes: a sheared magnetic field; magnetic curvature; and gradients in the background density, pressure and magnetic field. We incorporate wave-particle resonance interactions for electrons and ions to obtain the dissipation. The background magnetic Keld curvature and gradient give rise to drifts which alter the resonance condition for the various particle species (ω - k circ V d - k parallel v parallel ) and reduces the Landau damping of the kinetic Alfven wave, allowing it to propagate to the k parallel = 0 location

High resolution shear wave reflection surveying for hydrogeological investigations

International Nuclear Information System (INIS)

Johnson, W.J.; Clark, J.C.

1992-08-01

The high resolution S-wave method has been developed to be a powerful tool in mapping subsurface lithology and in conducting groundwater investigations. The research has demonstrated that the resolution obtainable using S-waves in a Coastal Plain environment is more than double than that obtained using conventional reflection, which already offers a higher resolution than any other surface method. Where the mapping of thin clay layers functioning as aquitards or thin sand layers functioning as aquifers are critical to the understanding of groundwater flow, S-wave reflections offer unparalleled possibilities for nondestructive exploration. The field experiment at Cooke Crossroads, South Carolina enabled the detection and mapping of beds in the thickness range of one to three feet. The S-wave reflection technique, in combination with conventional P-wave reflection, has potential to directly detect confined and unconfined aquifers. This is a breakthrough technology that still requires additional research before it can be applied on a commercial basis. Aquifer systems were interpreted from the test data at Cooke Crossroads consistent with theoretical model. Additional research is need in assessing the theoretical response of P- and S-waves to subsurface interfaces within unconsolidated sediments of varying moisture content and lithology. More theoretical modeling and in situ testing are needed to bring our knowledge of these phenomena to the level that oil and gas researchers have done for fluids in sandstones

Quantitative isotope incorporation reveals substrate partitioning in a coastal microbial community.

Science.gov (United States)

Mayali, Xavier; Weber, Peter K

2018-05-01

To quantitatively link microbial identity with biogeochemical function, we carried out 14 simultaneous stable isotope probing experiments with organic and inorganic C and N substrates to measure the isotope incorporation by over one hundred co-occurring eukaryotic and prokaryotic populations in a coastal community. We found that nitrate was the most commonly incorporated substrate, and that light-driven carbon fixation was carried out by some bacterial taxa from the Flavobacteriales and OM60 (NOR5) clade, in addition to photoautotrophic phytoplankton. We found that organisms that incorporated starch, maltose, glucose, lactose and bicarbonate were phylogenetically clustered, suggesting that specific bacterial lineages specialized in the incorporation of these substrates. The data further revealed that coastal microorganisms spanned a range of resource utilization strategies from generalists to specialists and demonstrated a high level of substrate partitioning, with two thirds of taxa exhibiting unique substrate incorporation patterns and the remaining third shared by no more than three OTUs each. Specialists exhibited more extreme incorporation levels (high or low), whereas generalists displayed more intermediate activity levels. These results shed valuable insights into the bottom-up ecological strategies enabling the persistence of high microbial diversity in aquatic ecosystems.

Wave fronts of electromagnetic cyclotron harmonic waves

International Nuclear Information System (INIS)

Ohnuma, T.; Watanabe, T.

1982-01-01

In an inhomogeneous high-density magnetized plasma, the spatial properties of the wave fronts and ray trajectories of electromagnetic ordinary and extraordinary cyclotron harmonic waves are investigated. Those waves which are radiated from a local source are found to have wave fronts which are almost parallel to the magnetic field. Also, the reflective properties of the electromagnetic cyclotron harmonic waves are confirmed

Acoustic waves in unbounded shear flows

International Nuclear Information System (INIS)

Chagelishvili, G.D.; Khujadze, G.R.; Lominadze, J.G.; Rogava, A.D.

1996-05-01

The linear evolution of acoustic waves in fluid flow with constant density and uniform shear of velocity is investigated. The process of the mean flow energy extraction by the three-dimensional acoustic waves which is due to the non-normality of linear dynamics in shear flows is analyzed. The thorough examination of the dynamics of different physical quantities, specifying the wave evolution, is outlined. The revealing of the behaviour becomes possible owing to the nonmodal approach that has been extensively used in the study of the perturbations evolution in shear flows since the beginning of the nineties. In addition, a detailed analyses of the physics of shear energy gain by vortex and acoustic perturbations is presented. (author). 28 refs, 7 figs

Validation of simulations of an underwater acoustic communication channel characterized by wind-generated surface waves and bubbles

NARCIS (Netherlands)

Dol, H.S.; Colin, M.E.G.D.; Ainlie, M.A.; Gerdes, F.; Schäfke, A.; Özkan Sertlekc, H.

2013-01-01

This paper shows that it is possible to simulate realistic shallow-water acoustic communication channels using available acoustic propagation models. Key factor is the incorporation of realistic time-dependent sea surface conditions, including both waves and bubbles due to wind.

A CFD study of wave influence on film steam condensation in the presence of non-condensable gas

Energy Technology Data Exchange (ETDEWEB)

Wang, Xianmao, E-mail: xm-wang11@mails.tsinghua.edu.cn [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Chang, Huajian, E-mail: changhj@tsinghua.edu.cn [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Corradini, Michael, E-mail: corradini@engr.wisc.edu [Department of Engineering Physics, University of Wisconsin-Madison, 1500 Engineering Drive, Madison, WI 53706 (United States)

2016-08-15

Highlights: • A condensation model is incorporated in the ANSYS FLUENT. • Different turbulence models are evaluated for flows over wavy surfaces. • Wavy surfaces with and without moving velocities are used to model the wave. • Various wavy surfaces with different wave heights and wavelengths are selected. • Wave influence on film steam condensation is investigated. - Abstract: Steam condensation plays an important role in removing heat from the containment of a nuclear plant during postulated accidents. However, due to the presence of non-condensable gases such as air and hydrogen in the containment, the condensation rate can decrease dramatically. Under certain conditions, the condensate film on the cold containment walls can affect the overall heat transfer rate. The wavy interface of the condensate film is a factor and is usually believed to enhance the condensation rate, since the waves can both increase the interfacial area and disturb the non-condensable gas boundary layer. However, it is not clear how to properly account for this factor and what is its quantitative influence in experiments. In this work, a CFD approach is applied to study the wave effects on film condensation in the presence of non-condensable gas. Wavy surfaces with and without moving velocities are used to replace the wavy interface of the falling film. A condensation model is incorporated in the ANSYS FLUENT simulation and a realizable k–ε turbulence model is applied. Various wavy surfaces with different wave heights and wavelengths are selected to conduct numerical experiments with a wide range of gas velocities. The results show that the wave structure can enhance condensation rate up to ten percent mainly due to the alteration of local flow structures in the gas phase. The increments of the condensation rate due to the wavy interface can vary with different gas velocities. The investigation shows that a multiplication factor accounts for the wave effects on film

Wave Equation Inversion of Skeletonized SurfaceWaves

KAUST Repository

Zhang, Zhendong; Liu, Yike; Schuster, Gerard T.

2015-01-01

We present a surface-wave inversion method that inverts for the S-wave velocity from the Rayleigh dispersion curve for the fundamental-mode. We call this wave equation inversion of skeletonized surface waves because the dispersion curve

A NEW VIEW OF CORONAL WAVES FROM STEREO

International Nuclear Information System (INIS)

Ma, S.; Lin, J.; Zhao, S.; Li, Q.; Wills-Davey, M. J.; Attrill, G. D. R.; Golub, L.; Chen, P. F.; Chen, H.

2009-01-01

On 2007 December 7, there was an eruption from AR 10977, which also hosted a sigmoid. An EUV Imaging Telescope (EIT) wave associated with this eruption was observed by EUVI on board the Solar Terrestrial Relations Observatory (STEREO). Using EUVI images in the 171 A and the 195 A passbands from both STEREO A and B, we study the morphology and kinematics of this EIT wave. In the early stages, images of the EIT wave from the two STEREO spacecrafts differ markedly. We determine that the EUV fronts observed at the very beginning of the eruption likely include some intensity contribution from the associated coronal mass ejection (CME). Additionally, our velocity measurements suggest that the EIT wave front may propagate at nearly constant velocity. Both results offer constraints on current models and understanding of EIT waves.

Wave-particle dualism of spiral waves dynamics.

Science.gov (United States)

Biktasheva, I V; Biktashev, V N

2003-02-01

We demonstrate and explain a wave-particle dualism of such classical macroscopic phenomena as spiral waves in active media. That means although spiral waves appear as nonlocal processes involving the whole medium, they respond to small perturbations as effectively localized entities. The dualism appears as an emergent property of a nonlinear field and is mathematically expressed in terms of the spiral waves response functions, which are essentially nonzero only in the vicinity of the spiral wave core. Knowledge of the response functions allows quantitatively accurate prediction of the spiral wave drift due to small perturbations of any nature, which makes them as fundamental characteristics for spiral waves as mass is for the condensed matter.

Infrared and millimeter waves v.14 millimeter components and techniques, pt.V

CERN Document Server

Button, Kenneth J

1985-01-01

Infrared and Millimeter Waves, Volume 14: Millimeter Components and Techniques, Part V is concerned with millimeter-wave guided propagation and integrated circuits. In addition to millimeter-wave planar integrated circuits and subsystems, this book covers transducer configurations and integrated-circuit techniques, antenna arrays, optoelectronic devices, and tunable gyrotrons. Millimeter-wave gallium arsenide (GaAs) IMPATT diodes are also discussed. This monograph is comprised of six chapters and begins with a description of millimeter-wave integrated-circuit transducers, focusing on vario

Improvement of a picking algorithm real-time P-wave detection by kurtosis

Science.gov (United States)

Ishida, H.; Yamada, M.

2016-12-01

Earthquake early warning (EEW) requires fast and accurate P-wave detection. The current EEW system in Japan uses the STA/LTAalgorithm (Allen, 1978) to detect P-wave arrival.However, some stations did not trigger during the 2011 Great Tohoku Earthquake due to the emergent onset. In addition, accuracy of the P-wave detection is very important: on August 1, 2016, the EEW issued a false alarm with M9 in Tokyo region due to a thunder noise.To solve these problems, we use a P-wave detection method using kurtosis statistics. It detects the change of statistic distribution of the waveform amplitude. This method was recently developed (Saragiotis et al., 2002) and used for off-line analysis such as making seismic catalogs. To apply this method for EEW, we need to remove an acausal calculation and enable a real-time processing. Here, we propose a real-time P-wave detection method using kurtosis statistics with a noise filter.To avoid false triggering by a noise, we incorporated a simple filter to classify seismic signal and noise. Following Kong et al. (2016), we used the interquartilerange and zero cross rate for the classification. The interquartile range is an amplitude measure that is equal to the middle 50% of amplitude in a certain time window. The zero cross rate is a simple frequency measure that counts the number of times that the signal crosses baseline zero. A discriminant function including these measures was constructed by the linear discriminant analysis.To test this kurtosis method, we used strong motion records for 62 earthquakes between April, 2005 and July, 2015, which recorded the seismic intensity greater equal to 6 lower in the JMA intensity scale. The records with hypocentral distance picks. It shows that the median error is 0.13 sec and 0.035 sec for STA/LTA and kurtosis method. The kurtosis method tends to be more sensitive to small changes in amplitude.Our approach will contribute to improve the accuracy of source location determination of

A membrane wave equation for Q.C.D. (SU(infinity))

International Nuclear Information System (INIS)

Botelho, L.C.L.

1988-01-01

It is proposed a quantum membrane wave functional describing the interaction between a colored SU(N c ) membrane and a quantized Yang-Mills field. Additionally, its associated wave equation in the t'Hooft N c ->infinity limit is deduced. (A.C.A.S.) [pt

Ultra Deep Wave Equation Imaging and Illumination

Energy Technology Data Exchange (ETDEWEB)

Alexander M. Popovici; Sergey Fomel; Paul Sava; Sean Crawley; Yining Li; Cristian Lupascu

2006-09-30

In this project we developed and tested a novel technology, designed to enhance seismic resolution and imaging of ultra-deep complex geologic structures by using state-of-the-art wave-equation depth migration and wave-equation velocity model building technology for deeper data penetration and recovery, steeper dip and ultra-deep structure imaging, accurate velocity estimation for imaging and pore pressure prediction and accurate illumination and amplitude processing for extending the AVO prediction window. Ultra-deep wave-equation imaging provides greater resolution and accuracy under complex geologic structures where energy multipathing occurs, than what can be accomplished today with standard imaging technology. The objective of the research effort was to examine the feasibility of imaging ultra-deep structures onshore and offshore, by using (1) wave-equation migration, (2) angle-gathers velocity model building, and (3) wave-equation illumination and amplitude compensation. The effort consisted of answering critical technical questions that determine the feasibility of the proposed methodology, testing the theory on synthetic data, and finally applying the technology for imaging ultra-deep real data. Some of the questions answered by this research addressed: (1) the handling of true amplitudes in the downward continuation and imaging algorithm and the preservation of the amplitude with offset or amplitude with angle information required for AVO studies, (2) the effect of several imaging conditions on amplitudes, (3) non-elastic attenuation and approaches for recovering the amplitude and frequency, (4) the effect of aperture and illumination on imaging steep dips and on discriminating the velocities in the ultra-deep structures. All these effects were incorporated in the final imaging step of a real data set acquired specifically to address ultra-deep imaging issues, with large offsets (12,500 m) and long recording time (20 s).

RF wave simulation for cold edge plasmas using the MFEM library

Science.gov (United States)

Shiraiwa, S.; Wright, J. C.; Bonoli, P. T.; Kolev, T.; Stowell, M.

2017-10-01

A newly developed generic electro-magnetic (EM) simulation tool for modeling RF wave propagation in SOL plasmas is presented. The primary motivation of this development is to extend the domain partitioning approach for incorporating arbitrarily shaped SOL plasmas and antenna to the TORIC core ICRF solver, which was previously demonstrated in the 2D geometry [S. Shiraiwa, et. al., "HISTORIC: extending core ICRF wave simulation to include realistic SOL plasmas", Nucl. Fusion in press], to larger and more complicated simulations by including a 3D realistic antenna and integrating RF rectified sheath potential model. Such an extension requires a scalable high fidelity 3D edge plasma wave simulation. We used the MFEM [http://mfem.org], open source scalable C++ finite element method library, and developed a Python wrapper for MFEM (PyMFEM), and then a radio frequency (RF) wave physics module in Python. This approach allows for building a physics layer rapidly, while separating the physics implementation being apart from the numerical FEM implementation. An interactive modeling interface was built on pScope [S Shiraiwa, et. al. Fusion Eng. Des. 112, 835] to work with an RF simulation model in a complicated geometry.

Effect of Dynamical Phase on the Resonant Interaction Among Tsunami Edge Wave Modes

Science.gov (United States)

Geist, Eric L.

2018-04-01

Different modes of tsunami edge waves can interact through nonlinear resonance. During this process, edge waves that have very small initial amplitude can grow to be as large or larger than the initially dominant edge wave modes. In this study, the effects of dynamical phase are established for a single triad of edge waves that participate in resonant interactions. In previous studies, Jacobi elliptic functions were used to describe the slow variation in amplitude associated with the interaction. This analytical approach assumes that one of the edge waves in the triad has zero initial amplitude and that the combined phase of the three waves φ = θ 1 + θ 2 - θ 3 is constant at the value for maximum energy exchange ( φ = 0). To obtain a more general solution, dynamical phase effects and non-zero initial amplitudes for all three waves are incorporated using numerical methods for the governing differential equations. Results were obtained using initial conditions calculated from a subduction zone, inter-plate thrust fault geometry and a stochastic earthquake slip model. The effect of dynamical phase is most apparent when the initial amplitudes and frequencies of the three waves are within an order of magnitude. In this case, non-zero initial phase results in a marked decrease in energy exchange and a slight decrease in the period of the interaction. When there are large differences in frequency and/or initial amplitude, dynamical phase has less of an effect and typically one wave of the triad has very little energy exchange with the other two waves. Results from this study help elucidate under what conditions edge waves might be implicated in late, large-amplitude arrivals.

Effect of Dynamical Phase on the Resonant Interaction Among Tsunami Edge Wave Modes

Science.gov (United States)

Geist, Eric L.

2018-02-01

Different modes of tsunami edge waves can interact through nonlinear resonance. During this process, edge waves that have very small initial amplitude can grow to be as large or larger than the initially dominant edge wave modes. In this study, the effects of dynamical phase are established for a single triad of edge waves that participate in resonant interactions. In previous studies, Jacobi elliptic functions were used to describe the slow variation in amplitude associated with the interaction. This analytical approach assumes that one of the edge waves in the triad has zero initial amplitude and that the combined phase of the three waves φ = θ 1 + θ 2 - θ 3 is constant at the value for maximum energy exchange (φ = 0). To obtain a more general solution, dynamical phase effects and non-zero initial amplitudes for all three waves are incorporated using numerical methods for the governing differential equations. Results were obtained using initial conditions calculated from a subduction zone, inter-plate thrust fault geometry and a stochastic earthquake slip model. The effect of dynamical phase is most apparent when the initial amplitudes and frequencies of the three waves are within an order of magnitude. In this case, non-zero initial phase results in a marked decrease in energy exchange and a slight decrease in the period of the interaction. When there are large differences in frequency and/or initial amplitude, dynamical phase has less of an effect and typically one wave of the triad has very little energy exchange with the other two waves. Results from this study help elucidate under what conditions edge waves might be implicated in late, large-amplitude arrivals.

BFR Electrolyte Additive Safety and Flammability Characterization

Energy Technology Data Exchange (ETDEWEB)

Allcorn, Eric [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-10-13

Lithium-ion battery safety is a critical issue in the adoption of the chemistry to larger scale applications such as transportation and stationary storage. One of the critical components impacting the safety of lithium-ion batteries is their use of highly flammable organic electrolytes. In this work, brominated flame retardants (BFR’s) – an existing class of flame retardant materials – are incorporated as additives to lithium-ion battery electrolytes with the intention to reduce the electrolyte flammability and thereby improve safety. There are a few critical needs for a successful electrolyte additive: solubility in the electrolyte, electrochemical stability over the range of battery operation, and minimal detrimental effects on battery performance. Those detrimental effects can take the form of electrolyte specific impacts, such as a reduction in conductivity, or electrode impacts, such as SEI-layer modification or chemical instability to the active material. In addition to these needs, the electrolyte additive also needs to achieve its intended purpose, which in this case is to reduce the flammability of the electrolyte. For the work conducted as part of this SPP agreement three separate BFR materials were provided by Albemarle to be tested by Sandia as additives in a traditional lithium-ion battery electrolyte. The provided BFR materials were tribromo-neopentyl alcohol, tetrabromo bisphenol A, and tribromoethylene. These materials were incorporated as separate 4 wt.% additives into a traditional lithium-ion battery electrolyte and compared to said traditional electrolyte, designated Gen2.

Simulation of breaking waves using the high-order spectral method with laboratory experiments: Wave-breaking onset

Science.gov (United States)

Seiffert, Betsy R.; Ducrozet, Guillaume; Bonnefoy, Félicien

2017-11-01

waves provides a wide range of breaking-wave strengths, types and scales for validation of the model. A comparison of calculations made using HOS-NWT with experimental measurements show that the model is successful at predicting the occurrence of wave breaking, as well as accurately calculating breaking onset time and location. Although the current study is limited to a unidirectional wave field, the success of the wave-breaking model presented provides the basis for application of the model in a multidirectional wave field. By including wave breaking onset with the addition of an appropriate energy dissipation model into HOS-NWT, we can increase the application range of the model, as well as decrease the occurrence of numerical instabilities that are associated with breaking waves in a potential flow solver. An accurate description of the wave field is useful for predicting the dynamic response of offshore vessels and marine renewable energy devices, predicting loads on marine structures and the general physics of ocean waves, for example.

CMS-Wave

Science.gov (United States)

2015-10-30

Coastal Inlets Research Program CMS -Wave CMS -Wave is a two-dimensional spectral wind-wave generation and transformation model that employs a forward...marching, finite-difference method to solve the wave action conservation equation. Capabilities of CMS -Wave include wave shoaling, refraction... CMS -Wave can be used in either on a half- or full-plane mode, with primary waves propagating from the seaward boundary toward shore. It can

Regression analysis and transfer function in estimating the parameters of central pulse waves from brachial pulse wave.

Science.gov (United States)

Chai Rui; Li Si-Man; Xu Li-Sheng; Yao Yang; Hao Li-Ling

2017-07-01

This study mainly analyzed the parameters such as ascending branch slope (A_slope), dicrotic notch height (Hn), diastolic area (Ad) and systolic area (As) diastolic blood pressure (DBP), systolic blood pressure (SBP), pulse pressure (PP), subendocardial viability ratio (SEVR), waveform parameter (k), stroke volume (SV), cardiac output (CO) and peripheral resistance (RS) of central pulse wave invasively and non-invasively measured. These parameters extracted from the central pulse wave invasively measured were compared with the parameters measured from the brachial pulse waves by a regression model and a transfer function model. The accuracy of the parameters which were estimated by the regression model and the transfer function model was compared too. Our findings showed that in addition to the k value, the above parameters of the central pulse wave and the brachial pulse wave invasively measured had positive correlation. Both the regression model parameters including A_slope, DBP, SEVR and the transfer function model parameters had good consistency with the parameters invasively measured, and they had the same effect of consistency. The regression equations of the three parameters were expressed by Y'=a+bx. The SBP, PP, SV, CO of central pulse wave could be calculated through the regression model, but their accuracies were worse than that of transfer function model.

Between tide and wave marks: a unifying model of physical zonation on littoral shores

Directory of Open Access Journals (Sweden)

Christopher E. Bird

2013-09-01

Full Text Available The effects of tides on littoral marine habitats are so ubiquitous that shorelines are commonly described as ‘intertidal’, whereas waves are considered a secondary factor that simply modifies the intertidal habitat. However mean significant wave height exceeds tidal range at many locations worldwide. Here we construct a simple sinusoidal model of coastal water level based on both tidal range and wave height. From the patterns of emergence and submergence predicted by the model, we derive four vertical shoreline benchmarks which bracket up to three novel, spatially distinct, and physically defined zones. The (1 emergent tidal zone is characterized by tidally driven emergence in air; the (2 wave zone is characterized by constant (not periodic wave wash; and the (3 submergent tidal zone is characterized by tidally driven submergence. The decoupling of tidally driven emergence and submergence made possible by wave action is a critical prediction of the model. On wave-dominated shores (wave height ≫ tidal range, all three zones are predicted to exist separately, but on tide-dominated shores (tidal range ≫ wave height the wave zone is absent and the emergent and submergent tidal zones overlap substantially, forming the traditional “intertidal zone”. We conclude by incorporating time and space in the model to illustrate variability in the physical conditions and zonation on littoral shores. The wave:tide physical zonation model is a unifying framework that can facilitate our understanding of physical conditions on littoral shores whether tropical or temperate, marine or lentic.

Pseudospectral modeling and dispersion analysis of Rayleigh waves in viscoelastic media

Science.gov (United States)

Zhang, K.; Luo, Y.; Xia, J.; Chen, C.

2011-01-01

Multichannel Analysis of Surface Waves (MASW) is one of the most widely used techniques in environmental and engineering geophysics to determine shear-wave velocities and dynamic properties, which is based on the elastic layered system theory. Wave propagation in the Earth, however, has been recognized as viscoelastic and the propagation of Rayleigh waves presents substantial differences in viscoelastic media as compared with elastic media. Therefore, it is necessary to carry out numerical simulation and dispersion analysis of Rayleigh waves in viscoelastic media to better understand Rayleigh-wave behaviors in the real world. We apply a pseudospectral method to the calculation of the spatial derivatives using a Chebyshev difference operator in the vertical direction and a Fourier difference operator in the horizontal direction based on the velocity-stress elastodynamic equations and relations of linear viscoelastic solids. This approach stretches the spatial discrete grid to have a minimum grid size near the free surface so that high accuracy and resolution are achieved at the free surface, which allows an effective incorporation of the free surface boundary conditions since the Chebyshev method is nonperiodic. We first use an elastic homogeneous half-space model to demonstrate the accuracy of the pseudospectral method comparing with the analytical solution, and verify the correctness of the numerical modeling results for a viscoelastic half-space comparing the phase velocities of Rayleigh wave between the theoretical values and the dispersive image generated by high-resolution linear Radon transform. We then simulate three types of two-layer models to analyze dispersive-energy characteristics for near-surface applications. Results demonstrate that the phase velocity of Rayleigh waves in viscoelastic media is relatively higher than in elastic media and the fundamental mode increases by 10-16% when the frequency is above 10. Hz due to the velocity dispersion of P

Effectiveness of reinforcement incorporation and mechanical properties of composites produced from rheocast slurries

Energy Technology Data Exchange (ETDEWEB)

Robert, M.H.; Galvao da Silveira Mussi, R. [Faculty of Mechanical Engineering, State Univ. of Campinas, Cidade Univ. (Brazil)

2002-07-01

The influence of compocasting variables (SiC size and %vol, additions of grain refiner and extra Mg) in the quality of A356+SiCp MMCs is investigated. In all conditions microstructures show Al-{alpha} with globular morphology with eutectic and SiC in interglobular regions. Results show tendency of agglomeration of thinner particles, jeopardising their incorporation and dispersion in the matrix; high quantities of SiC are not incorporated into rheocast slurries with refined globules, grain refinement decreases incorporation of bigger particles. Extra Mg does not influence incorporation. Best results are obtained for 15% vol of 30 {mu}m SiC added to grain refined matrix. Mechanical properties are poor when agglomeration of particles is present. (orig.)

A note on poroacoustic traveling waves under Forchheimer's law

International Nuclear Information System (INIS)

Jordan, P.M.

2013-01-01

Acoustic traveling waves in a gas that saturates a rigid porous medium is investigated under the assumption that the drag experienced by the gas is modeled by Forchheimer's law. Exact traveling wave solutions (TWS)s, as well as approximate and asymptotic expressions, are obtained; decay rates are determined; and acceleration wave results are presented. In addition, special cases are considered, critical values of the wave variable and parameters are derived, and comparisons with predictions based on Darcy's law are performed. It is shown that, with respect to the Darcy case, most of the metrics that characterize such waveforms exhibit an increase in magnitude under Forchheimer's law

Auroral kilometric radiation - An example of relativistic wave-particle interaction in geoplasma

International Nuclear Information System (INIS)

Pritchett, P.L.

1990-01-01

The earth's auroral kilometric radiation (AKR) is believed to be produced by the electron-cyclotron maser instability. This instability is the result of a wave-particle interaction in which relativistic effects are crucial. An explanation is given as to how these relativistic effects alter the shape of the resonance curve in velocity space and modify the R - X mode wave dispersion near the electron cyclotron frequency compared to the results obtained in the nonrelativistic limit and from cold-plasma theory. The properties of the cyclotron maser instability in a driven system are illustrated using two-dimensional electromagnetic particle simulations which incorporate a continual flow of primary energetic electrons along the magnetic field. 31 refs

Internal wave focusing revisited; a reanalysis and new theoretical links

International Nuclear Information System (INIS)

Lam, Frans-Peter A; Maas, Leo R M

2008-01-01

An experiment which discussed the appearance of an internal wave attractor in a uniformly stratified, free-surface fluid [Maas, L.R.M., Benielli, D., Sommeria, J., Lam, F.-P.A., 1997. Observation of an internal wave attractor in a confined, stably stratified fluid. Nature 388(6642), 557-561] is revisited. This is done in order to give a more detailed and more accurate description of the underlying focusing process. Evolution of the attractor can now be quantified. For the tank with one sloping sidewall, and for the parameter regime (density stratification, forcing frequency) studied, the inverse exponential growth rate determined at several locations in the fluid turns out to be 122 s always. Only the start and duration of the growth differed: away from the attractor region it appeared later and of shorter duration. Here, these features are interpreted by employing a new theoretical basis that incorporates an external forcing via a surface boundary condition (an infinitesimal barotropic seiche) and that describes the solution in terms of propagating waves.

GDP-tubulin incorporation into growing microtubules modulates polymer stability.

Science.gov (United States)

Valiron, Odile; Arnal, Isabelle; Caudron, Nicolas; Job, Didier

2010-06-04

Microtubule growth proceeds through the endwise addition of nucleotide-bound tubulin dimers. The microtubule wall is composed of GDP-tubulin subunits, which are thought to come exclusively from the incorporation of GTP-tubulin complexes at microtubule ends followed by GTP hydrolysis within the polymer. The possibility of a direct GDP-tubulin incorporation into growing polymers is regarded as hardly compatible with recent structural data. Here, we have examined GTP-tubulin and GDP-tubulin incorporation into polymerizing microtubules using a minimal assembly system comprised of nucleotide-bound tubulin dimers, in the absence of free nucleotide. We find that GDP-tubulin complexes can efficiently co-polymerize with GTP-tubulin complexes during microtubule assembly. GDP-tubulin incorporation into microtubules occurs with similar efficiency during bulk microtubule assembly as during microtubule growth from seeds or centrosomes. Microtubules formed from GTP-tubulin/GDP-tubulin mixtures display altered microtubule dynamics, in particular a decreased shrinkage rate, apparently due to intrinsic modifications of the polymer disassembly properties. Thus, although microtubules polymerized from GTP-tubulin/GDP-tubulin mixtures or from homogeneous GTP-tubulin solutions are both composed of GDP-tubulin subunits, they have different dynamic properties, and this may reveal a novel form of microtubule "structural plasticity."

Formation of whispering gallery modes by scattering of an electromagnetic plane wave by two cylinders

Energy Technology Data Exchange (ETDEWEB)

Abramov, Arnold, E-mail: qulaser@gmail.com [Kuang-Chi Institute of Advanced Technology, Shenzhen, 518057 (China); Kostikov, Alexander [Donbass State Engineering Academy, 84303, Kramatorsk, Donetsk (Ukraine)

2017-03-26

We report the effect of scattering of electromagnetic plane waves by two cylinders on whispering gallery mode (WGM) formation in a cylinder. WGM can occur because of the presence of additional cylinder scatterers at specific location, while WGMs can only form in a single cylinder for specific cylinder radius and/or wavelength values, the matching accuracy required would be much greater than that required in our model for the additional cylinders locations. Analysis of the general solution to the problem showed that the effect can be explained by the interference of waves scattered by additional cylinders and incident on the main cylinder. - Highlights: • We consider scattering of electromagnetic plane waves by two cylinders. • WGMs occur because of the presence of additional cylinder at specific location. • The accuracy for the locations is much less than required for specific values of single cylinder. • The interference of waves scattered by additional cylinders and incident on the main is responsible for the effect.

Monolithic millimeter-wave and picosecond electronic technologies

International Nuclear Information System (INIS)

Talley, W.K.; Luhmann, N.C.

1996-01-01

Theoretical and experimental studies into monolithic millimeter-wave and picosecond electronic technologies have been undertaken as a collaborative project between the Lawrence Livermore National Laboratory (LLNL) and the University of California Department of Applied Science Coherent Millimeter-Wave Group under the auspices of the Laboratory Directed Research and Development Program at LLNL. The work involves the design and fabrication of monolithic frequency multiplier, beam control, and imaging arrays for millimeter-wave imaging and radar, as well as the development of high speed nonlinear transmission lines for ultra-wideband radar imaging, time domain materials characterization and magnetic fusion plasma applications. In addition, the Coherent Millimeter-Wave Group is involved in the fabrication of a state-of-the-art X-band (∼8-11 GHz) RF photoinjector source aimed at producing psec high brightness electron bunches for advanced accelerator and coherent radiation generation studies

Wave-induced ripple development in mixed clay-sand substrates

Science.gov (United States)

Wu, Xuxu; Parsons, Daniel; Baas, Jaco H.; Mouazé, Dominique; McLelland, Stuart; Amoudry, Laurent; Eggenhuisen, Jorris; Cartigny, Matthieu; Ruessink, Gerben

2016-04-01

This paper reports on a series of experiments that aim to provide a fuller understanding of ripple development within clay-sand mixture substrates under oscillatory flow conditions. The work was conducted in the Total Environment Simulator at the University of Hull and constituted 6 separate runs, in which 5 runs were conducted under identical sets of regular waves (an additional run was conducted under irregular waves, but is not discussed in present paper). The bed content was systematically varied in its composition ranging from a pure sand bed through to a bed comprising 7.4% clay. A series of state-of-the-art measurements were employed to quantify interactions of near-bed hydrodynamics, sediment transport, and turbulence over rippled beds formed by wave action, during and after, each run. The experimental results demonstrate the significant influence of the amount of cohesive clay materials in the substrate on ripple evolution under waves. Most importantly, addition of clay in the bed dramatically slowed down the rate of ripple development and evolution. The equilibrium time of each run increased exponentially from 30 minutes under the control conditions of a pure sand bed, rising to ~350 minutes for the bed with the highest fraction of clay. The paper discusses the slower ripple growth rates with higher cohesive fractions, via an influence on critical shear, but highlights that the end equilibrium size of ripples is found to be independent of increasing substrate clay fraction. The suspended particles mass (SPM) concentration indicates that clay particles were suspended and winnowed by wave action. Additionally, laser granulometry of the final substrates verified that ripple crests were composed of pure sand layers that were absent at ripple troughs, reflecting a relatively higher winnowing efficiency at wave ripples crest. The winnowing process and its efficiency is inexorably linked to wave ripple development and evolution. The implications of the results

Simulation of Wave-Plus-Current Scour beneath Submarine Pipelines

DEFF Research Database (Denmark)

Eltard-Larsen, Bjarke; Fuhrman, David R.; Sumer, B. Mutlu

2016-01-01

A fully coupled hydrodynamic and morphologic numerical model was utilized for the simulation of wave-plus-current scour beneath submarine pipelines. The model was based on incompressible Reynolds-averaged Navier–Stokes equations, coupled with k-ω turbulence closure, with additional bed and suspen......A fully coupled hydrodynamic and morphologic numerical model was utilized for the simulation of wave-plus-current scour beneath submarine pipelines. The model was based on incompressible Reynolds-averaged Navier–Stokes equations, coupled with k-ω turbulence closure, with additional bed...... and suspended load descriptions forming the basis for seabed morphology. The model was successfully validated against experimental measurements involving scour development and eventual equilibrium in pure-current flows over a range of Shields parameters characteristic of both clear-water and live-bed regimes....... This validation complements previously demonstrated accuracy for the same model in simulating pipeline scour processes in pure-wave environments. The model was subsequently utilized to simulate combined wave-plus-current scour over a wide range of combined Keulegan–Carpenter numbers and relative current strengths...

Wavelet-based multiscale adjoint waveform-difference tomography using body and surface waves

Science.gov (United States)

Yuan, Y. O.; Simons, F. J.; Bozdag, E.

2014-12-01

We present a multi-scale scheme for full elastic waveform-difference inversion. Using a wavelet transform proves to be a key factor to mitigate cycle-skipping effects. We start with coarse representations of the seismogram to correct a large-scale background model, and subsequently explain the residuals in the fine scales of the seismogram to map the heterogeneities with great complexity. We have previously applied the multi-scale approach successfully to body waves generated in a standard model from the exploration industry: a modified two-dimensional elastic Marmousi model. With this model we explored the optimal choice of wavelet family, number of vanishing moments and decomposition depth. For this presentation we explore the sensitivity of surface waves in waveform-difference tomography. The incorporation of surface waves is rife with cycle-skipping problems compared to the inversions considering body waves only. We implemented an envelope-based objective function probed via a multi-scale wavelet analysis to measure the distance between predicted and target surface-wave waveforms in a synthetic model of heterogeneous near-surface structure. Our proposed method successfully purges the local minima present in the waveform-difference misfit surface. An elastic shallow model with 100~m in depth is used to test the surface-wave inversion scheme. We also analyzed the sensitivities of surface waves and body waves in full waveform inversions, as well as the effects of incorrect density information on elastic parameter inversions. Based on those numerical experiments, we ultimately formalized a flexible scheme to consider both body and surface waves in adjoint tomography. While our early examples are constructed from exploration-style settings, our procedure will be very valuable for the study of global network data.

Carnauba straw incorporated into the soil for fertilization carrot in organic cultivation

Directory of Open Access Journals (Sweden)

Micharlyson Carlos Morais

2017-10-01

Full Text Available Carrot is one of the most produced vegetables in Brazil and, with the growing demand for organic vegetables, it is necessary to develop production technologies that are less dependent on external inputs and more accessible to family agriculture. The objective of this study was to evaluate the effect of the addition to soil of carnauba straw as fertilizer, incorporated under different pre-planting periods, for the organic cultivation of the carrot. The experiment was carried out in the Experimental Horta of the Instituto Federal do Rio Grande do Norte, Campus Ipanguaçu, using the experimental design in randomized blocks with three replicates and five treatments referring to the times of 15; 30; 45 and 60 days for the incorporation of carnauba straw, in the amount of 14 t ha-1, prior to planting the carrot, and a control treatment without addition of straw to the soil. The evaluated characteristics was dry mass of the aerial part, the length and root diameter, and productivity. There was an effect of the incorporation time of the carnauba straw on the length and productivity, being the highest values observed when the straw was incorporated between 15 and 30 days before sowing.

Modeling Stop-and-Go Waves in Pedestrian Dynamics

OpenAIRE

Portz, Andrea; Seyfried, Armin

2010-01-01

Several spatially continuous pedestrian dynamics models have been validated against empirical data. We try to reproduce the experimental fundamental diagram (velocity versus density) with simulations. In addition to this quantitative criterion, we tried to reproduce stop-and-go waves as a qualitative criterion. Stop-and-go waves are a characteristic phenomenon for the single file movement. Only one of three investigated models satisfies both criteria.

Broadband one-dimensional photonic crystal wave plate containing single-negative materials.

Science.gov (United States)

Chen, Yihang

2010-09-13

The properties of the phase shift of wave reflected from one-dimensional photonic crystals consisting of periodic layers of single-negative (permittivity- or permeability-negative) materials are demonstrated. As the incident angle increases, the reflection phase shift of TE wave decreases, while that of TM wave increases. The phase shifts of both polarized waves vary smoothly as the frequency changes across the photonic crystal stop band. Consequently, the difference between the phase shift of TE and that of TM wave could remain constant in a rather wide frequency range inside the stop band. These properties are useful to design wave plate or retarder which can be used in wide spectral band. In addition, a broadband photonic crystal quarter-wave plate is proposed.

Infragravity Waves Produced by Wave Groups on Beaches

Institute of Scientific and Technical Information of China (English)

邹志利; 常梅

2003-01-01

The generation of low frequency waves by a single or double wave groups incident upon two plane beaches with the slope of 1/40 and 1/100 is investigated experimentally and numerically. A new type of wave maker signal is used to generate the groups, allowing the bound long wave (set-down) to be included in the group. The experiments show that the low frequency wave is generated during breaking and propagation to the shoreline of the wave group. This process of generation and propagation of low frequency waves is simulated numerically by solving the short-wave averaged mass and momentum conservation equations. The computed and measured results are in good agreement. The mechanism of generation of low frequency waves in the surf zone is examined and discussed.

Ciliary metachronal wave propagation on the compliant surface of Paramecium cells.

Science.gov (United States)

Narematsu, Naoki; Quek, Raymond; Chiam, Keng-Hwee; Iwadate, Yoshiaki

2015-12-01

Ciliary movements in protozoa exhibit metachronal wave-like coordination, in which a constant phase difference is maintained between adjacent cilia. It is at present generally thought that metachronal waves require hydrodynamic coupling between adjacent cilia and the extracellular fluid. To test this hypothesis, we aspirated a Paramecium cell using a micropipette which completely sealed the surface of the cell such that no fluid could pass through the micropipette. Thus, the anterior and the posterior regions of the cell were hydrodynamically decoupled. Nevertheless, we still observed that metachronal waves continued to propagate from the anterior to the posterior ends of the cell, suggesting that in addition to hydrodynamic coupling, there are other mechanisms that can also transmit the metachronal waves. Such transmission was also observed in computational modeling where the fluid was fully decoupled between two partitions of a beating ciliary array. We also imposed cyclic stretching on the surface of live Paramecium cells and found that metachronal waves persisted in the presence of cyclic stretching. This demonstrated that, in addition to hydrodynamic coupling, a compliant substrate can also play a critical role in mediating the propagation of metachronal waves. © 2015 Wiley Periodicals, Inc.

Photonic Crystal Biosensor Based on Optical Surface Waves

Directory of Open Access Journals (Sweden)

Giovanni Dietler

2013-02-01

Full Text Available A label-free biosensor device based on registration of photonic crystal surface waves is described. Angular interrogation of the optical surface wave resonance is used to detect changes in the thickness of an adsorbed layer, while an additional simultaneous detection of the critical angle of total internal reflection provides independent data of the liquid refractive index. The abilities of the device are demonstrated by measuring of biotin molecule binding to a streptavidin monolayer, and by measuring association and dissociation kinetics of immunoglobulin G proteins. Additionally, deposition of PSS / PAH polyelectrolytes is recorded in situ resulting calculation of PSS and PAH monolayer thicknesses separately.

Wave Power Demonstration Project at Reedsport, Oregon

Energy Technology Data Exchange (ETDEWEB)

Mekhiche, Mike [Principal Investigator; Downie, Bruce [Project Manager

2013-10-21

Ocean wave power can be a significant source of large‐scale, renewable energy for the US electrical grid. The Electrical Power Research Institute (EPRI) conservatively estimated that 20% of all US electricity could be generated by wave energy. Ocean Power Technologies, Inc. (OPT), with funding from private sources and the US Navy, developed the PowerBuoy to generate renewable energy from the readily available power in ocean waves. OPT's PowerBuoy converts the energy in ocean waves to electricity using the rise and fall of waves to move the buoy up and down (mechanical stroking) which drives an electric generator. This electricity is then conditioned and transmitted ashore as high‐voltage power via underwater cable. OPT's wave power generation system includes sophisticated techniques to automatically tune the system for efficient conversion of random wave energy into low cost green electricity, for disconnecting the system in large waves for hardware safety and protection, and for automatically restoring operation when wave conditions normalize. As the first utility scale wave power project in the US, the Wave Power Demonstration Project at Reedsport, OR, will consist of 10 PowerBuoys located 2.5 miles off the coast. This U.S. Department of Energy Grant funding along with funding from PNGC Power, an Oregon‐based electric power cooperative, was utilized for the design completion, fabrication, assembly and factory testing of the first PowerBuoy for the Reedsport project. At this time, the design and fabrication of this first PowerBuoy and factory testing of the power take‐off subsystem are complete; additionally the power take‐off subsystem has been successfully integrated into the spar.

Plane waves and structures in turbulent channel flow

Science.gov (United States)

Sirovich, L.; Ball, K. S.; Keefe, L. R.

1990-01-01

A direct simulation of turbulent flow in a channel is analyzed by the method of empirical eigenfunctions (Karhunen-Loeve procedure, proper orthogonal decomposition). This analysis reveals the presence of propagating plane waves in the turbulent flow. The velocity of propagation is determined by the flow velocity at the location of maximal Reynolds stress. The analysis further suggests that the interaction of these waves appears to be essential to the local production of turbulence via bursting or sweeping events in the turbulent boundary layer, with the additional suggestion that the fast acting plane waves act as triggers.

Nonlinear wave chaos: statistics of second harmonic fields.

Science.gov (United States)

Zhou, Min; Ott, Edward; Antonsen, Thomas M; Anlage, Steven M

2017-10-01

Concepts from the field of wave chaos have been shown to successfully predict the statistical properties of linear electromagnetic fields in electrically large enclosures. The Random Coupling Model (RCM) describes these properties by incorporating both universal features described by Random Matrix Theory and the system-specific features of particular system realizations. In an effort to extend this approach to the nonlinear domain, we add an active nonlinear frequency-doubling circuit to an otherwise linear wave chaotic system, and we measure the statistical properties of the resulting second harmonic fields. We develop an RCM-based model of this system as two linear chaotic cavities coupled by means of a nonlinear transfer function. The harmonic field strengths are predicted to be the product of two statistical quantities and the nonlinearity characteristics. Statistical results from measurement-based calculation, RCM-based simulation, and direct experimental measurements are compared and show good agreement over many decades of power.

Numerical Investigation of Three-dimensional Instability of Standing Waves

Science.gov (United States)

Zhu, Qiang; Liu, Yuming; Yue, Dick K. P.

2002-11-01

We study the three-dimensional instability of finite-amplitude standing waves under the influence of gravity using the transition matrix method. For accurate calculation of the transition matrices, we apply an efficient high-order spectral element method for nonlinear wave dynamics in complex domain. We consider two types of standing waves: (a) plane standing waves; and (b) standing waves in a circular tank. For the former, in addition to the confirmation of the side-band-like instability, we find a new three-dimensional instability for arbitrary base standing waves. The dominant component of the unstable disturbance is an oblique standing wave, with an arbitrary angle relative to the base flow, whose frequency is approximately equal to that of the base standing wave. Based on direct simulations, we confirm such a three-dimensional instability and show the occurrence of the Fermi-Pasta-Ulam recurrence phenomenon during nonlinear evolution. For the latter, we find that beyond a threshold wave steepness, the standing wave with frequency Ω becomes unstable to a small three-dimensional disturbance, which contains two dominant standing-wave components with frequencies ω1 and ω_2, provided that 2Ω ω1 + ω_2. The threshold wave steepness is found to decrease/increase as the radial/azimuthal wavenumber of the base standing wave increases. We show that the instability of standing waves in rectangular and circular tanks is caused by third-order quartet resonances between base flow and disturbance.

Experimental evaluation of the effect of wave focusing walls on the performance of the Sea-wave Slot-cone Generator

International Nuclear Information System (INIS)

Oliveira, P.; Taveira-Pinto, F.; Morais, T.; Rosa-Santos, P.

2016-01-01

addition, in comparison to the base configuration, the hydraulic efficiencies with concentrators were higher for the smaller significant wave heights, but smaller for the other sea conditions. The use of wave concentrators increased the annual energy production approximately to the double. Overall, the application of the SSG technology in breakwaters presents itself as promising considering the characteristics of the wave resource nearshore or even in onshore locations.

Parametric pendulum based wave energy converter

Science.gov (United States)

Yurchenko, Daniil; Alevras, Panagiotis

2018-01-01

The paper investigates the dynamics of a novel wave energy converter based on the parametrically excited pendulum. The herein developed concept of the parametric pendulum allows reducing the influence of the gravity force thereby significantly improving the device performance at a regular sea state, which could not be achieved in the earlier proposed original point-absorber design. The suggested design of a wave energy converter achieves a dominant rotational motion without any additional mechanisms, like a gearbox, or any active control involvement. Presented numerical results of deterministic and stochastic modeling clearly reflect the advantage of the proposed design. A set of experimental results confirms the numerical findings and validates the new design of a parametric pendulum based wave energy converter. Power harvesting potential of the novel device is also presented.

In vitro incorporation of the phage Phi29 connector complex

International Nuclear Information System (INIS)

Fu Chiyu; Prevelige, Peter E.

2009-01-01

The incorporation of the DNA packaging connector complex during lambdoid phage assembly in vivo is strictly controlled-one and only one of the twelve identical icosahedral vertices is differentiated by the inclusion of a portal or connector dodecamer. Proposed control mechanisms include obligate nucleation from a connector containing complex, addition of the connector as the final step during assembly, and a connector-mediated increase in the growth rate. The inability to recapitulate connector incorporation in vitro has made it difficult to obtain direct biochemical evidence in support of one model over another. Here we report the development an in vitro assembly system for the well characterized dsDNA phage Phi29 which results in the co-assembly of connector with capsid and scaffolding proteins to form procapsid-like particles (PLPs). Immuno-electron microscopy demonstrates the specific incorporation of connector vertex in PLPs. The connector protein increases both the yield and the rate of capsid assembly suggesting that the incorporation of the connector in Phi29 likely promotes nucleation of assembly.

Fabrication on a ZnO/ST-cut quartz based love wave viscosity sensor

Energy Technology Data Exchange (ETDEWEB)

Wu, Tsung Tsong; Huang, Zhi Da; Chen, Yung Yu; Liu, Pei Ling [Institute of Applied Mechanics, National Taiwan University, Taipai (China)

2006-05-15

In this paper, we aim to propose a rugged and relatively inexpensive acoustic wave viscometer that is easy to use and to fabricate by the conventional semiconductor manufacturing processes. First, we fabricated five different Love wave acoustic devices based on ZnO/90 degree rotated ST-quartz layered structure and incorporated with Polydimethylsiloxane (PMDS) flow cell. This allows a tiny controlled amount of analyte to be confined solely upon the sensing area between the IDTs of our Love wave sensor, preventing unwanted electric interactions with IDTs. The PDMS liquid flow cell is fabricated by replica molding. Using a simple set of fixture, the flow cell can be clamped onto our Love wave sensor and a constant volume of analyte can be confined on the sensing surface. Finally, five glycerites with different viscosities were prepared for viscosity measurement. The measured results show that the frequency shifts are in good correlation with the known viscosities. We note that results of this study can further be implemented as an easy to use and inexpensive acoustic viscometer.

Fabrication od a ZnO/ST-cut quartz based love wave viscosity sensor

Energy Technology Data Exchange (ETDEWEB)

Wu, Tsung Tsong; Huang, Zhi Da; Chen, Yung Yu; Liu, Pei Ling [Institute of Applied Mechanics, National Taiwan University, Taipai (China)

2006-05-15

In this paper, we aim to propose a rugged and relatively inexpensive acoustic wave viscometer that is easy to use and to fabricate by the conventional semiconductor manufacturing processes. First, we fabricated five different Love wave acoustic devices based on ZnO/90 degree rotated ST-quartz layered structure and incorporated with Polydimethylsiloxane (PMDS) flow cell. This allows a tiny controlled amount of analyte to be confined solely upon the sensing area between the IDTs of our Love wave sensor, preventing unwanted electric interactions with IDTs. The PDMS liquid flow cell is fabricated by replica molding. Using a simple set of fixture, the flow cell can be clamped onto our Love wave sensor and a constant volume of analyte can be confined on the sensing surface. Finally, five glycerites with different viscosities were prepared for viscosity measurement. The measured results show that the frequency shifts are in good correlation with the known viscosities. We note that results of this study can further be implemented as an easy to use and inexpensive acoustic viscometer.

Fabrication od a ZnO/ST-cut quartz based love wave viscosity sensor

International Nuclear Information System (INIS)

Wu, Tsung Tsong; Huang, Zhi Da; Chen, Yung Yu; Liu, Pei Ling

2006-01-01

In this paper, we aim to propose a rugged and relatively inexpensive acoustic wave viscometer that is easy to use and to fabricate by the conventional semiconductor manufacturing processes. First, we fabricated five different Love wave acoustic devices based on ZnO/90 degree rotated ST-quartz layered structure and incorporated with Polydimethylsiloxane (PMDS) flow cell. This allows a tiny controlled amount of analyte to be confined solely upon the sensing area between the IDTs of our Love wave sensor, preventing unwanted electric interactions with IDTs. The PDMS liquid flow cell is fabricated by replica molding. Using a simple set of fixture, the flow cell can be clamped onto our Love wave sensor and a constant volume of analyte can be confined on the sensing surface. Finally, five glycerites with different viscosities were prepared for viscosity measurement. The measured results show that the frequency shifts are in good correlation with the known viscosities. We note that results of this study can further be implemented as an easy to use and inexpensive acoustic viscometer.

Fabrication on a ZnO/ST-cut quartz based love wave viscosity sensor

International Nuclear Information System (INIS)

Wu, Tsung Tsong; Huang, Zhi Da; Chen, Yung Yu; Liu, Pei Ling

2006-01-01

In this paper, we aim to propose a rugged and relatively inexpensive acoustic wave viscometer that is easy to use and to fabricate by the conventional semiconductor manufacturing processes. First, we fabricated five different Love wave acoustic devices based on ZnO/90 degree rotated ST-quartz layered structure and incorporated with Polydimethylsiloxane (PMDS) flow cell. This allows a tiny controlled amount of analyte to be confined solely upon the sensing area between the IDTs of our Love wave sensor, preventing unwanted electric interactions with IDTs. The PDMS liquid flow cell is fabricated by replica molding. Using a simple set of fixture, the flow cell can be clamped onto our Love wave sensor and a constant volume of analyte can be confined on the sensing surface. Finally, five glycerites with different viscosities were prepared for viscosity measurement. The measured results show that the frequency shifts are in good correlation with the known viscosities. We note that results of this study can further be implemented as an easy to use and inexpensive acoustic viscometer.

Process Stability of Ultrasonic-Wave-Assisted Gas Metal Arc Welding

Science.gov (United States)

Fan, Chenglei; Xie, Weifeng; Yang, Chunli; Lin, Sanbao; Fan, Yangyang

2017-10-01

As a newly developed arc welding method, ultrasonic-wave-assisted arc welding successfully introduced power ultrasound into the arc and weld pool, during which the ultrasonic acts on the top of the arc in the coaxial alignment direction. The advanced process for molten metals can be realized by using an additional ultrasonic field. Compared with the conventional gas metal arc welding (GMAW), the welding arc is compressed, the droplet size is decreased, and the droplet transfer frequency is increased significantly in ultrasonic-wave-assisted GMAW (U-GMAW). However, the stability of the metal transfer has deep influence on the welding quality equally, and the ultrasonic wave effect on the stability of the metal transfer is a phenomenon that is not completely understood. In this article, the stabilities of the short-circuiting transfer process and globular transfer process are studied systematically, and the effect of ultrasonic wave on the metal transfer is analyzed further. The transfer frequency and process stability of the U-GMAW process are much higher than those of the conventional GMAW. Analytical results show that the additional ultrasonic wave is helpful for improving welding stability.

Dynamic Excitation of Monopiles by Steep and Breaking Waves: Experimental and Numerical Study

DEFF Research Database (Denmark)

Bredmose, Henrik; Slabiak, Peter; Sahlberg-Nielsen, Lasse

2013-01-01

. Emphasis is given to the observed impulsive excitation of the natural modes by steep and breaking waves. Additionally, springing and ringing-type continuous forcing of the first natural mode is seen for the moderately steep waves. The experiments were carried out at three depths and with two wave climates...

DEMETER observations of manmade waves that propagate in the ionosphere

Science.gov (United States)

Parrot, Michel

2018-01-01

This paper is a review of manmade waves observed by the ionospheric satellite DEMETER. It concerns waves emitted by the ground-based VLF and ELF transmitters, by broadcasting stations, by the power line harmonic radiation, by industrial noise, and by active experiments. Examples are shown including, for the first time, the record of a wave coming from an ELF transmitter. These waves propagate upwards in the magnetosphere and they can be observed in the magnetically conjugated region of emission. Depending on their frequencies, they perturb the ionosphere and the particles in the radiation belts, and additional emissions are triggered. xml:lang="fr"

The effect of actuator bending on Lamb wave displacement fields generated by a piezoelectric patch

International Nuclear Information System (INIS)

Huang, H; Pamphile, T; Derriso, M

2008-01-01

A Lamb wave is a special type of elastic wave that is widely employed in structural health monitoring systems for damage detection. Recently, piezoelectric (piezo) patches have become popular for Lamb wave excitation and sensing because one piezo patch can serve as both the actuator and the sensor. All published work has assumed that the Lamb wave displacement field generated by a piezo patch actuator is axi-symmetric. However, we observed that piezo sensors placed at equal distances from the piezo patch actuator displayed different responses. In order to understand this phenomenon, we used a laser vibrometer to measure the full-field displacements around a circular piezo actuator noncontactly. The displacement fields excited by the piezo patch actuator are found to be directional, and this directionality is also frequency dependent, indicating that the out-of-plane bending dynamics of the piezo actuator may play an important role in the Lamb wave displacement fields. A simulation model that incorporates the bending deformation of the piezo patch into the calculations of the Lamb wave generation is then developed. The agreement between the simulated and measured displacement fields confirmed that the directionality of the Lamb wave displacement fields is governed by the bending deformation of the piezo patch actuator

Advances in low-cost long-wave infrared polymer windows

Science.gov (United States)

Weimer, Wayne A.; Klocek, Paul

1999-07-01

Recent improvements in engineered polymeric material compositions and advances in processing methodologies developed and patented at Raytheon Systems Company have produced long wave IR windows at exceptionally low costs. These UV stabilized, high strength windows incorporating subwavelength structured antireflection surfaces are enabling IR imaging systems to penetrate commercial markets and will reduce the cost of systems delivered to the military. The optical and mechanical properties of these windows will be discussed in detail with reference to the short and long-term impact on military IR imaging systems.

Advanced numerical technique for analysis of surface and bulk acoustic waves in resonators using periodic metal gratings

Science.gov (United States)

Naumenko, Natalya F.

2014-09-01

A numerical technique characterized by a unified approach for the analysis of different types of acoustic waves utilized in resonators in which a periodic metal grating is used for excitation and reflection of such waves is described. The combination of the Finite Element Method analysis of the electrode domain with the Spectral Domain Analysis (SDA) applied to the adjacent upper and lower semi-infinite regions, which may be multilayered and include air as a special case of a dielectric material, enables rigorous simulation of the admittance in resonators using surface acoustic waves, Love waves, plate modes including Lamb waves, Stonely waves, and other waves propagating along the interface between two media, and waves with transient structure between the mentioned types. The matrix formalism with improved convergence incorporated into SDA provides fast and robust simulation for multilayered structures with arbitrary thickness of each layer. The described technique is illustrated by a few examples of its application to various combinations of LiNbO3, isotropic silicon dioxide and silicon with a periodic array of Cu electrodes. The wave characteristics extracted from the admittance functions change continuously with the variation of the film and plate thicknesses over wide ranges, even when the wave nature changes. The transformation of the wave nature with the variation of the layer thicknesses is illustrated by diagrams and contour plots of the displacements calculated at resonant frequencies.

pp-waves in 11-dimensions

International Nuclear Information System (INIS)

Gauntlett, Jerome P.; Hull, Christopher M.

2002-01-01

The Killing spinor equations for pp-wave solutions of eleven dimensional supergravity are analysed and it is shown that there are solutions that preserve 18, 20, 22 and 24 supersymmetries, in addition to the generic solution preserving 16 supersymmetries and the Kowalski-Glikman solution preserving 32 supersymmetries. (author)

The Role of Localized Compressional Ultra-low Frequency Waves in Energetic Electron Precipitation

Science.gov (United States)

Rae, I. Jonathan; Murphy, Kyle R.; Watt, Clare E. J.; Halford, Alexa J.; Mann, Ian R.; Ozeke, Louis G.; Sibeck, David G.; Clilverd, Mark A.; Rodger, Craig J.; Degeling, Alex W.; Forsyth, Colin; Singer, Howard J.

2018-03-01

Typically, ultra-low frequency (ULF) waves have historically been invoked for radial diffusive transport leading to acceleration and loss of outer radiation belt electrons. At higher frequencies, very low frequency waves are generally thought to provide a mechanism for localized acceleration and loss through precipitation into the ionosphere of radiation belt electrons. In this study we present a new mechanism for electron loss through precipitation into the ionosphere due to a direct modulation of the loss cone via localized compressional ULF waves. We present a case study of compressional wave activity in tandem with riometer and balloon-borne electron precipitation across keV-MeV energies to demonstrate that the experimental measurements can be explained by our new enhanced loss cone mechanism. Observational evidence is presented demonstrating that modulation of the equatorial loss cone can occur via localized compressional wave activity, which greatly exceeds the change in pitch angle through conservation of the first and second adiabatic invariants. The precipitation response can be a complex interplay between electron energy, the localization of the waves, the shape of the phase space density profile at low pitch angles, ionospheric decay time scales, and the time dependence of the electron source; we show that two pivotal components not usually considered are localized ULF wave fields and ionospheric decay time scales. We conclude that enhanced precipitation driven by compressional ULF wave modulation of the loss cone is a viable candidate for direct precipitation of radiation belt electrons without any additional requirement for gyroresonant wave-particle interaction. Additional mechanisms would be complementary and additive in providing means to precipitate electrons from the radiation belts during storm times.

Saturation of Langmuir waves in laser-produced plasmas

International Nuclear Information System (INIS)

Baker, K.L.

1996-04-01

This dissertation deals with the interaction of an intense laser with a plasma (a quasineutral collection of electrons and ions). During this interaction, the laser drives large-amplitude waves through a class of processes known as parametric instabilities. Several such instabilities drive one type of wave, the Langmuir wave, which involves oscillations of the electrons relative to the nearly-stationary ions. There are a number of mechanisms which limit the amplitude to which Langmuir waves grow. In this dissertation, these mechanisms are examined to identify qualitative features which might be observed in experiments and/or simulations. In addition, a number of experiments are proposed to specifically look for particular saturation mechanisms. In a plasma, a Langmuir wave can decay into an electromagnetic wave and an ion wave. This parametric instability is proposed as a source for electromagnetic emission near half of the incident laser frequency observed from laser-produced plasmas. This interpretation is shown to be consistent with existing experimental data and it is found that one of the previous mechanisms used to explain such emission is not. The scattering version of the electromagnetic decay instability is shown to provide an enhanced noise source of electromagnetic waves near the frequency of the incident laser

Nonlinear VLF Wave Physics in the Radiation Belts

Science.gov (United States)

Crabtree, C. E.; Tejero, E. M.; Ganguli, G.; Mithaiwala, M.; Rudakov, L.; Hospodarsky, G. B.; Kletzing, C.

2014-12-01

Electromagnetic VLF waves, such as whistler mode waves, both control the lifetime of trapped electrons in the radiation belts by pitch-angle scattering and are responsible for the energization of electrons during storms. Traditional approaches to understanding the influence of waves on trapped electrons have assumed that the wave characteristics (frequency spectrum, wave-normal angle distribution, etc.) were both stationary in time and amplitude independent from event to event. In situ data from modern satellite missions, such as the Van Allen probes, are showing that this assumption may not be justified. In addition, recent theoretical results [Crabtree et al. 2012] show that the threshold for nonlinear wave scattering can often be met by naturally occurring VLF waves in the magnetosphere, with wave magnetic fields of the order of 50-100 pT inside the plasmapause. Nonlinear wave scattering (Nonlinear Landau Damping) is an amplitude dependent mechanism that can strongly alter VLF wave propagation [Ganguli et al. 2010], primarily by altering the direction of propagation. Laboratory results have confirmed the dramatic change in propagation direction when the pump wave has sufficient amplitude to exceed the nonlinear threshold [Tejero et al. 2014]. Nonlinear scattering can alter the macroscopic dynamics of waves in the radiation belts leading to the formation of a long-lasting wave-cavity [Crabtree et al. 2012] and, when amplification is present, a multi-pass amplifier [Ganguli et al., 2012]. Such nonlinear wave effects can dramatically reduce electron lifetimes. Nonlinear wave dynamics such as these occur when there are more than one wave present, such a condition necessarily violates the assumption of traditional wave-normal analysis [Santolik et al., 2003] which rely on the plane wave assumption. To investigate nonlinear wave dynamics using modern in situ data we apply the maximum entropy method [Skilling and Bryan, 1984] to solve for the wave distribution function

Emissive sensors and devices incorporating these sensors

Science.gov (United States)

Swager, Timothy M; Zhang, Shi-Wei

2013-02-05

The present invention generally relates to luminescent and/or optically absorbing compositions and/or precursors to those compositions, including solid films incorporating these compositions/precursors, exhibiting increased luminescent lifetimes, quantum yields, enhanced stabilities and/or amplified emissions. The present invention also relates to sensors and methods for sensing analytes through luminescent and/or optically absorbing properties of these compositions and/or precursors. Examples of analytes detectable by the invention include electrophiles, alkylating agents, thionyl halides, and phosphate ester groups including phosphoryl halides, cyanides and thioates such as those found in certain chemical warfare agents. The present invention additionally relates to devices and methods for amplifying emissions, such as those produced using the above-described compositions and/or precursors, by incorporating the composition and/or precursor within a polymer having an energy migration pathway. In some cases, the compositions and/or precursors thereof include a compound capable of undergoing a cyclization reaction.

A Framework Incorporating Community Preferences in Use ...

Science.gov (United States)

The report is intended to assist water quality officials, watershed managers, members of stakeholder groups, and other interested individuals in fully evaluating ecological and socioeconomic objectives and the gains and losses that often are involved in use attainment decisions. In addition, this report enables local, state, and tribal managers to better understand the benefits, as well as the costs, of attaining high water quality, and to incorporate community preferences in decision-making. Specific objectives are (1) to provide an introduction to the CWA and WQS regulation and analyses related to setting or changing designated uses; (2) create a basis for understanding the relationship between use-attainment decisions and the effects on ecosystems, ecosystem services, and ecological benefits; (3) serve as reference for methods that elicit or infer preferences for benefits and costs related to attaining uses and (4) present process for incorporating new approaches in water quality decisions.

The physics of orographic gravity wave drag

Directory of Open Access Journals (Sweden)

Miguel A C Teixeira

2014-07-01

Full Text Available The drag and momentum fluxes produced by gravity waves generated in flow over orography are reviewed, focusing on adiabatic conditions without phase transitions or radiation effects, and steady mean incoming flow. The orographic gravity wave drag is first introduced in its simplest possible form, for inviscid, linearized, non-rotating flow with the Boussinesq and hydrostatic approximations, and constant wind and static stability. Subsequently, the contributions made by previous authors (primarily using theory and numerical simulations to elucidate how the drag is affected by additional physical processes are surveyed. These include the effect of orography anisotropy, vertical wind shear, total and partial critical levels, vertical wave reflection and resonance, non-hydrostatic effects and trapped lee waves, rotation and nonlinearity. Frictional and boundary layer effects are also briefly mentioned. A better understanding of all of these aspects is important for guiding the improvement of drag parametrization schemes.

Effect of dynamical phase on the resonant interaction among tsunami edge wave modes

Science.gov (United States)

Geist, Eric L.

2018-01-01

Different modes of tsunami edge waves can interact through nonlinear resonance. During this process, edge waves that have very small initial amplitude can grow to be as large or larger than the initially dominant edge wave modes. In this study, the effects of dynamical phase are established for a single triad of edge waves that participate in resonant interactions. In previous studies, Jacobi elliptic functions were used to describe the slow variation in amplitude associated with the interaction. This analytical approach assumes that one of the edge waves in the triad has zero initial amplitude and that the combined phase of the three waves φ = θ1 + θ2 − θ3 is constant at the value for maximum energy exchange (φ = 0). To obtain a more general solution, dynamical phase effects and non-zero initial amplitudes for all three waves are incorporated using numerical methods for the governing differential equations. Results were obtained using initial conditions calculated from a subduction zone, inter-plate thrust fault geometry and a stochastic earthquake slip model. The effect of dynamical phase is most apparent when the initial amplitudes and frequencies of the three waves are within an order of magnitude. In this case, non-zero initial phase results in a marked decrease in energy exchange and a slight decrease in the period of the interaction. When there are large differences in frequency and/or initial amplitude, dynamical phase has less of an effect and typically one wave of the triad has very little energy exchange with the other two waves. Results from this study help elucidate under what conditions edge waves might be implicated in late, large-amplitude arrivals.

Wave attenuation across a tidal marsh in San Francisco Bay

Science.gov (United States)

Foster-Martinez, Madeline R.; Lacy, Jessica; Ferner, Matthew C.; Variano, Evan A.

2018-01-01

Wave attenuation is a central process in the mechanics of a healthy salt marsh. Understanding how wave attenuation varies with vegetation and hydrodynamic conditions informs models of other marsh processes that are a function of wave energy (e.g. sediment transport) and allows for the incorporation of marshes into coastal protection plans. Here, we examine the evolution of wave height across a tidal salt marsh in San Francisco Bay. Instruments were deployed along a cross-shore transect, starting on the mudflat and crossing through zones dominated by Spartina foliosa and Salicornia pacifica. This dataset is the first to quantify wave attenuation for these vegetation species, which are abundant in the intertidal zone of California estuaries. Measurements were collected in the summer and winter to assess seasonal variation in wave attenuation. Calculated drag coefficients of S. foliosa and S. pacifica were similar, indicating equal amounts of vegetation would lead to similar energy dissipation; however, S. pacifica has much greater biomass close to the bed (<20 cm) and retains biomass throughout the year, and therefore, it causes more total attenuation. S. foliosa dies back in the winter, and waves often grow across this section of the marsh. For both vegetation types, attenuation was greatest for low water depths, when the vegetation was emergent. For both seasons, attenuation rates across S. pacifica were the highest and were greater than published attenuation rates across similar (Spartina alterniflora) salt marshes for the comparable depths. These results can inform designs for marsh restorations and management plans in San Francisco Bay and other estuaries containing these species.

Gravitational wave memory in ΛCDM cosmology

International Nuclear Information System (INIS)

Bieri, Lydia; Garfinkle, David; Yunes, Nicolás

2017-01-01

We examine gravitational wave memory in the case where sources and detector are in a ΛCDM cosmology. We consider the case where the Universe can be highly inhomogeneous, but gravitational radiation is treated in the short wavelength approximation. We find results very similar to those of gravitational wave memory in an asymptotically flat spacetime; however, the overall magnitude of the memory effect is enhanced by a redshift-dependent factor. In addition, we find the memory can be affected by lensing. (paper)

Syntheses and characterization of liposome-incorporated adamantyl aminoguanidines.

Science.gov (United States)

Šekutor, Marina; Štimac, Adela; Mlinarić-Majerski, Kata; Frkanec, Ruža

2014-08-21

A series of mono and bis-aminoguanidinium adamantane derivatives has been synthesized and incorporated into liposomes. They combine two biomedically significant molecules, the adamantane moiety and the guanidinium group. The adamantane moiety possesses the membrane compatible features while the cationic guanidinium subunit was recognized as a favourable structural feature for binding to complementary molecules comprising phosphate groups. The liposome formulations of adamantyl aminoguanidines were characterized and it was shown that the entrapment efficiency of the examined compounds is significant. In addition, it was demonstrated that liposomes with incorporated adamantyl aminoguanidines effectively recognized the complementary liposomes via the phosphate group. These results indicate that adamantane derivatives bearing guanidinium groups might be versatile tools for biomedical application, from studies of molecular recognition processes to usage in drug formulation and cell targeting.

Wave Dragon Wave Energy Converters Used as Coastal Protection

DEFF Research Database (Denmark)

Nørgaard, Jørgen Harck; Andersen, Thomas Lykke; Kofoed, Jens Peter

2011-01-01

This paper deals with wave energy converters used to reduce the wave height along shorelines. For this study the Wave Dragon wave energy converter is chosen. The wave height reduction from a single device has been evaluated from physical model tests in scale 1:51.8 of the 260 x 150 m, 24 kW/m model...... Spain, to evaluate the potential for reducing wave heights close the shore by means of Wave Dragons....

Collisional damping rates for plasma waves

Energy Technology Data Exchange (ETDEWEB)

Tigik, S. F., E-mail: sabrina.tigik@ufrgs.br; Ziebell, L. F., E-mail: luiz.ziebell@ufrgs.br [Instituto de Física, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre, Rio Grande do Sul (Brazil); Yoon, P. H., E-mail: yoonp@umd.edu [Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742 (United States); School of Space Research, Kyung Hee University, Yongin, Gyeonggi 446-701 (Korea, Republic of)

2016-06-15

The distinction between the plasma dynamics dominated by collisional transport versus collective processes has never been rigorously addressed until recently. A recent paper [P. H. Yoon et al., Phys. Rev. E 93, 033203 (2016)] formulates for the first time, a unified kinetic theory in which collective processes and collisional dynamics are systematically incorporated from first principles. One of the outcomes of such a formalism is the rigorous derivation of collisional damping rates for Langmuir and ion-acoustic waves, which can be contrasted to the heuristic customary approach. However, the results are given only in formal mathematical expressions. The present brief communication numerically evaluates the rigorous collisional damping rates by considering the case of plasma particles with Maxwellian velocity distribution function so as to assess the consequence of the rigorous formalism in a quantitative manner. Comparison with the heuristic (“Spitzer”) formula shows that the accurate damping rates are much lower in magnitude than the conventional expression, which implies that the traditional approach over-estimates the importance of attenuation of plasma waves by collisional relaxation process. Such a finding may have a wide applicability ranging from laboratory to space and astrophysical plasmas.

Electromagnetic waves in gravitational wave spacetimes

International Nuclear Information System (INIS)

Haney, M.; Bini, D.; Ortolan, A.; Fortini, P.

2013-01-01

We have considered the propagation of electromagnetic waves in a space-time representing an exact gravitational plane wave and calculated the induced changes on the four-potential field Aμ of a plane electromagnetic wave. By choosing a suitable photon round-trip in a Michelson interferometer, we have been able to identify the physical effects of the exact gravitational wave on the electromagnetic field, i.e. phase shift, change of the polarization vector, angular deflection and delay. These results have been exploited to study the response of an interferometric gravitational wave detector beyond the linear approximation of the general theory of relativity. A much more detailed examination of this problem can be found in our paper recently published in Classical and Quantum Gravity (28 (2011) 235007).

The interaction of energetic alpha-particles with intense lower hybrid waves

International Nuclear Information System (INIS)

Fisch, N.J.; Rax, J.M.

1992-06-01

Lower hybrid waves are a demonstrated, continuous means of driving toroidal current in a tokamak. When these waves propagate in a tokamak fusion reactor, in which there are energetic α- particles, there are conditions under which the α-particles do not appreciably damp, and may even amplify, the wave, thereby enhancing the current-drive effect. Waves traveling in one poloidal direction, in addition to being directed in one toroidal direction, are shown to be the most efficient drivers of current in the presence of the energetic α-particles

Quasiparticle conductance-voltage characteristics for break junctions involving d-wave superconductors: charge-density-wave effects.

Science.gov (United States)

Ekino, T; Gabovich, A M; Suan Li, Mai; Szymczak, H; Voitenko, A I

2017-12-20

Quasiparticle tunnel conductance-voltage characteristics (CVCs), [Formula: see text], were calculated for break junctions (BJs) made up of layered d-wave superconductors partially gapped by charge-density waves (CDWs). The current is assumed to flow in the ab-plane of electrodes. The influence of CDWs is analyzed by comparing the resulting CVCs with CVCs calculated for BJs made up of pure d-wave superconductors with relevant parameters. The main CDW-effects were found to be the appearance of new CVC peculiarities and the loss of CVC symmetry with respect to the V-sign. Tunnel directionality was shown to be one of the key factors in the formation of [Formula: see text] dependences. In particular, the orientation of electrodes with respect to the current channel becomes very important. As a result, [Formula: see text] can acquire a large variety of forms similar to those for tunnel junctions between superconductors with s-wave, d-wave, and mixed symmetry of their order parameters. The diversity of peculiarities is especially striking at finite temperatures. In the case of BJs made up of pure d-wave superconductors, the resulting CVC can include a two-peak gap-driven structure. The results were compared with the experimental BJ data for a number of high-T c oxides. It was shown that the large variety of the observed current-voltage characteristics can be interpreted in the framework of our approach. Thus, quasiparticle tunnel currents in the ab-plane can be used as an additional mean to detect CDWs competing with superconductivity in cuprates or other layered superconductors.

Acoustic wave emission for enhanced oil recovery (WAVE.O.R.)

International Nuclear Information System (INIS)

Reichmann, S.; Amro, M.; Giese, R.; Jaksch, K.; Krauss, F.; Krueger, K.; Jurczyk, A.

2016-09-01

In the project WAVE.O.R the potential of acoustic waves to enhance oil recovery was reviewed. The project focused on laboratory experiments of the oil displacement in sandstone cores under acoustic stimulation. Additionally, the Seismic Prediction While Drilling (SPWD) borehole device prototype was set up for a feasibility field test. The laboratory experiments showed that, depending on the stimulation frequency, acoustic stimulation allows for an enhanced oil recovery. For single frequency stimulation a mean increase of 3 % pore volumes was observed at distinguished frequencies. A cyclic stimulation, where two of these frequencies were combined, an increase of 5% pore volume was observed. The SPWD borehole device was tested and adjusted during feasibility tests in the GFZ underground laboratory in the research and education mine ''Reiche Zeche'' of the TU Bergakademie Freiberg and in the GFZ KTB-Deep Laboratory in Windischeschenbach. The first successful test of the device under realistic conditions was performed at the test site ''Piana di Toppo'' of the OGS Trieste, Italy.

Surface wave effects in the NEMO ocean model: Forced and coupled experiments

Science.gov (United States)

Breivik, Øyvind; Mogensen, Kristian; Bidlot, Jean-Raymond; Balmaseda, Magdalena Alonso; Janssen, Peter A. E. M.

2015-04-01

The NEMO general circulation ocean model is extended to incorporate three physical processes related to ocean surface waves, namely the surface stress (modified by growth and dissipation of the oceanic wavefield), the turbulent kinetic energy flux from breaking waves, and the Stokes-Coriolis force. Experiments are done with NEMO in ocean-only (forced) mode and coupled to the ECMWF atmospheric and wave models. Ocean-only integrations are forced with fields from the ERA-Interim reanalysis. All three effects are noticeable in the extratropics, but the sea-state-dependent turbulent kinetic energy flux yields by far the largest difference. This is partly because the control run has too vigorous deep mixing due to an empirical mixing term in NEMO. We investigate the relation between this ad hoc mixing and Langmuir turbulence and find that it is much more effective than the Langmuir parameterization used in NEMO. The biases in sea surface temperature as well as subsurface temperature are reduced, and the total ocean heat content exhibits a trend closer to that observed in a recent ocean reanalysis (ORAS4) when wave effects are included. Seasonal integrations of the coupled atmosphere-wave-ocean model consisting of NEMO, the wave model ECWAM, and the atmospheric model of ECMWF similarly show that the sea surface temperature biases are greatly reduced when the mixing is controlled by the sea state and properly weighted by the thickness of the uppermost level of the ocean model. These wave-related physical processes were recently implemented in the operational coupled ensemble forecast system of ECMWF.

The effects of noise on binocular rivalry waves: a stochastic neural field model

International Nuclear Information System (INIS)

Webber, Matthew A; Bressloff, Paul C

2013-01-01

We analyze the effects of extrinsic noise on traveling waves of visual perception in a competitive neural field model of binocular rivalry. The model consists of two one-dimensional excitatory neural fields, whose activity variables represent the responses to left-eye and right-eye stimuli, respectively. The two networks mutually inhibit each other, and slow adaptation is incorporated into the model by taking the network connections to exhibit synaptic depression. We first show how, in the absence of any noise, the system supports a propagating composite wave consisting of an invading activity front in one network co-moving with a retreating front in the other network. Using a separation of time scales and perturbation methods previously developed for stochastic reaction–diffusion equations, we then show how extrinsic noise in the activity variables leads to a diffusive-like displacement (wandering) of the composite wave from its uniformly translating position at long time scales, and fluctuations in the wave profile around its instantaneous position at short time scales. We use our analysis to calculate the first-passage-time distribution for a stochastic rivalry wave to travel a fixed distance, which we find to be given by an inverse Gaussian. Finally, we investigate the effects of noise in the depression variables, which under an adiabatic approximation lead to quenched disorder in the neural fields during propagation of a wave. (paper)

Incorporating functional inter-relationships into protein function prediction algorithms

Directory of Open Access Journals (Sweden)

Kumar Vipin

2009-05-01

Full Text Available Abstract Background Functional classification schemes (e.g. the Gene Ontology that serve as the basis for annotation efforts in several organisms are often the source of gold standard information for computational efforts at supervised protein function prediction. While successful function prediction algorithms have been developed, few previous efforts have utilized more than the protein-to-functional class label information provided by such knowledge bases. For instance, the Gene Ontology not only captures protein annotations to a set of functional classes, but it also arranges these classes in a DAG-based hierarchy that captures rich inter-relationships between different classes. These inter-relationships present both opportunities, such as the potential for additional training examples for small classes from larger related classes, and challenges, such as a harder to learn distinction between similar GO terms, for standard classification-based approaches. Results We propose a method to enhance the performance of classification-based protein function prediction algorithms by addressing the issue of using these interrelationships between functional classes constituting functional classification schemes. Using a standard measure for evaluating the semantic similarity between nodes in an ontology, we quantify and incorporate these inter-relationships into the k-nearest neighbor classifier. We present experiments on several large genomic data sets, each of which is used for the modeling and prediction of over hundred classes from the GO Biological Process ontology. The results show that this incorporation produces more accurate predictions for a large number of the functional classes considered, and also that the classes benefitted most by this approach are those containing the fewest members. In addition, we show how our proposed framework can be used for integrating information from the entire GO hierarchy for improving the accuracy of

Benefits of up-wave measurements in linear short-term wave forecasting for wave energy applications

OpenAIRE

Paparella, Francesco; Monk, Kieran; Winands, Victor; Lopes, Miguel; Conley, Daniel; Ringwood, John

2014-01-01

The real-time control of wave energy converters requires the prediction of the wave elevation at the location of the device in order to maximize the power extracted from the waves. One possibility is to predict the future wave elevation by combining its past history with the spatial information coming from a sensor which measures the free surface elevation upwave of the wave energy converter. As an application example, the paper focuses on the prediction of the wave eleva...

Nonlinear Whistler Wave Physics in the Radiation Belts

Science.gov (United States)

Crabtree, Chris

2016-10-01

Wave particle interactions between electrons and whistler waves are a dominant mechanism for controlling the dynamics of energetic electrons in the radiation belts. They are responsible for loss, via pitch-angle scattering of electrons into the loss cone, and energization to millions of electron volts. It has previously been theorized that large amplitude waves on the whistler branch may scatter their wave-vector nonlinearly via nonlinear Landau damping leading to important consequences for the global distribution of whistler wave energy density and hence the energetic electrons. It can dramatically reduce the lifetime of energetic electrons in the radiation belts by increasing the pitch angle scattering rate. The fundamental building block of this theory has now been confirmed through laboratory experiments. Here we report on in situ observations of wave electro-magnetic fields from the EMFISIS instrument on board NASA's Van Allen Probes that show the signatures of nonlinear scattering of whistler waves in the inner radiation belts. In the outer radiation belts, whistler mode chorus is believed to be responsible for the energization of electrons from 10s of Kev to MeV energies. Chorus is characterized by bursty large amplitude whistler mode waves with frequencies that change as a function of time on timescales corresponding to their growth. Theories explaining the chirping have been developed for decades based on electron trapping dynamics in a coherent wave. New high time resolution wave data from the Van Allen probes and advanced spectral techniques are revealing that the wave dynamics is highly structured, with sub-elements consisting of multiple chirping waves with discrete frequency hops between sub-elements. Laboratory experiments with energetic electron beams are currently reproducing the complex frequency vs time dynamics of whistler waves and in addition revealing signatures of wave-wave and beat-wave nonlinear wave-particle interactions. These new data

Spin dynamics and implications for superconductivity. Some problems with the d-wave scenario

International Nuclear Information System (INIS)

Levin, K.; Zha, Y.; Radtke, R.J.; Si, Q.; Norman, M.R.; Schuettler, H.B.

1994-01-01

We review the spin dynamics of the normal state of the cuprates with special emphasis on neutron data in both the YBa 2 Cu 3 O 7-δ and La 2-x Sr x CuO 4 systems. When realistic models of the Fermi surface shapes are incorporated, along with a moderate degree of spin fluctuations, we find good semiquantitative agreement with experiment for both cuprates. Building on the success of this Fermi-liquid-based scheme, we explore the implications for d-wave pairing from a number of vantage points. We conclude that our present experimental and theoretical understanding is inadequate to confirm or refute the d-wave scenario. 26 refs., 6 figs

Estimation of waves and ship responses using onboard measurements

DEFF Research Database (Denmark)

Montazeri, Najmeh

This thesis focuses on estimation of waves and ship responses using ship-board measurements. This is useful for development of operational safety and performance efficiency in connection with the broader concept of onboard decision support systems. Estimation of sea state is studied using a set...... of measured ship responses, a parametric description of directional wave spectra (a generalised JONSWAP model) and the transfer functions of the ship responses. The difference between the spectral moments of the measured ship responses and the corresponding theoretically calculated moments formulates a cost...... information. The model is tested on simulated data based on known unimodal and bimodal wave scenarios. The wave parameters in the output are then compared with the true wave parameters. In addition to the numerical experiments, two sets of full-scale measurements from container ships are analysed. Herein...

Propagation of ionization waves during ignition of fluorescent lamps

International Nuclear Information System (INIS)

Langer, R; Tidecks, R; Horn, S; Garner, R; Hilscher, A

2008-01-01

The propagation of the first ionization wave in a compact fluorescent lamp (T4 tube with standard electrodes) during ignition was investigated for various initial dc-voltages (both polarities measured against ground) and gas compositions (with and without mercury). In addition the effect of the presence of a fluorescent powder coating was studied. The propagation velocity of the initial wave was measured by an assembly of photomultipliers installed along the tube, which detected the light emitted by the wave head. The propagation was found to be faster for positive than for negative polarity. This effect is explained involving processes in the electrode region as well as in the wave head. Waves propagate faster in the presence of a fluorescent powder coating than without it and gases of lighter mass show a faster propagation than gases with higher mass

Wave-equation Qs Inversion of Skeletonized Surface Waves

KAUST Repository

Li, Jing

2017-02-08

We present a skeletonized inversion method that inverts surface-wave data for the Qs quality factor. Similar to the inversion of dispersion curves for the S-wave velocity model, the complicated surface-wave arrivals are skeletonized as simpler data, namely the amplitude spectra of the windowed Rayleigh-wave arrivals. The optimal Qs model is the one that minimizes the difference in the peak frequencies of the predicted and observed Rayleigh wave arrivals using a gradient-based wave-equation optimization method. Solutions to the viscoelastic wave-equation are used to compute the predicted Rayleigh-wave arrivals and the misfit gradient at every iteration. This procedure, denoted as wave-equation Qs inversion (WQs), does not require the assumption of a layered model and tends to have fast and robust convergence compared to full waveform inversion (FWI). Numerical examples with synthetic and field data demonstrate that the WQs method can accurately invert for a smoothed approximation to the subsurface Qs distribution as long as the Vs model is known with sufficient accuracy.

Skeletonized wave-equation Qs tomography using surface waves

KAUST Repository

Li, Jing

2017-08-17

We present a skeletonized inversion method that inverts surface-wave data for the Qs quality factor. Similar to the inversion of dispersion curves for the S-wave velocity model, the complicated surface-wave arrivals are skeletonized as simpler data, namely the amplitude spectra of the windowed Rayleigh-wave arrivals. The optimal Qs model is then found that minimizes the difference in the peak frequencies of the predicted and observed Rayleigh wave arrivals using a gradient-based wave-equation optimization method. Solutions to the viscoelastic wave-equation are used to compute the predicted Rayleigh-wave arrivals and the misfit gradient at every iteration. This procedure, denoted as wave-equation Qs tomography (WQs), does not require the assumption of a layered model and tends to have fast and robust convergence compared to Q full waveform inversion (Q-FWI). Numerical examples with synthetic and field data demonstrate that the WQs method can accurately invert for a smoothed approximation to the subsur-face Qs distribution as long as the Vs model is known with sufficient accuracy.

Wave-equation Qs Inversion of Skeletonized Surface Waves

KAUST Repository

Li, Jing; Dutta, Gaurav; Schuster, Gerard T.

2017-01-01

We present a skeletonized inversion method that inverts surface-wave data for the Qs quality factor. Similar to the inversion of dispersion curves for the S-wave velocity model, the complicated surface-wave arrivals are skeletonized as simpler data, namely the amplitude spectra of the windowed Rayleigh-wave arrivals. The optimal Qs model is the one that minimizes the difference in the peak frequencies of the predicted and observed Rayleigh wave arrivals using a gradient-based wave-equation optimization method. Solutions to the viscoelastic wave-equation are used to compute the predicted Rayleigh-wave arrivals and the misfit gradient at every iteration. This procedure, denoted as wave-equation Qs inversion (WQs), does not require the assumption of a layered model and tends to have fast and robust convergence compared to full waveform inversion (FWI). Numerical examples with synthetic and field data demonstrate that the WQs method can accurately invert for a smoothed approximation to the subsurface Qs distribution as long as the Vs model is known with sufficient accuracy.

Model for ICRF fast wave current drive in self-consistent MHD equilibria

International Nuclear Information System (INIS)

Bonoli, P.T.; Englade, R.C.; Porkolab, M.; Fenstermacher, M.E.

1993-01-01

Recently, a model for fast wave current drive in the ion cyclotron radio frequency (ICRF) range was incorporated into the current drive and MHD equilibrium code ACCOME. The ACCOME model combines a free boundary solution of the Grad Shafranov equation with the calculation of driven currents due to neutral beam injection, lower hybrid (LH) waves, bootstrap effects, and ICRF fast waves. The equilibrium and current drive packages iterate between each other to obtain an MHD equilibrium which is consistent with the profiles of driven current density. The ICRF current drive package combines a toroidal full-wave code (FISIC) with a parameterization of the current drive efficiency obtained from an adjoint solution of the Fokker Planck equation. The electron absorption calculation in the full-wave code properly accounts for the combined effects of electron Landau damping (ELD) and transit time magnetic pumping (TTMP), assuming a Maxwellian (or bi-Maxwellian) electron distribution function. Furthermore, the current drive efficiency includes the effects of particle trapping, momentum conserving corrections to the background Fokker Planck collision operator, and toroidally induced variations in the parallel wavenumbers of the injected ICRF waves. This model has been used to carry out detailed studies of advanced physics scenarios in the proposed Tokamak Physics Experiment (TPX). Results are shown, for example, which demonstrate the possibility of achieving stable equilibria at high beta and high bootstrap current fraction in TPX. Model results are also shown for the proposed ITER device

Parametric instability and wave turbulence driven by tidal excitation of internal waves

Science.gov (United States)

Le Reun, Thomas; Favier, Benjamin; Le Bars, Michael

2018-04-01

We investigate the stability of stratified fluid layers undergoing homogeneous and periodic tidal deformation. We first introduce a local model which allows to study velocity and buoyancy fluctuations in a Lagrangian domain periodically stretched and sheared by the tidal base flow. While keeping the key physical ingredients only, such a model is efficient to simulate planetary regimes where tidal amplitudes and dissipation are small. With this model, we prove that tidal flows are able to drive parametric subharmonic resonances of internal waves, in a way reminiscent of the elliptical instability in rotating fluids. The growth rates computed via Direct Numerical Simulations (DNS) are in very good agreement with WKB analysis and Floquet theory. We also investigate the turbulence driven by this instability mechanism. With spatio-temporal analysis, we show that it is a weak internal wave turbulence occurring at small Froude and buoyancy Reynolds numbers. When the gap between the excitation and the Brunt-V\\"ais\\"al\\"a frequencies is increased, the frequency spectrum of this wave turbulence displays a -2 power law reminiscent of the high-frequency branch of the Garett and Munk spectrum (Garrett & Munk 1979) which has been measured in the oceans. In addition, we find that the mixing efficiency is altered compared to what is computed in the context of DNS of stratified turbulence excited at small Froude and large buoyancy Reynolds numbers and is consistent with a superposition of waves.

Direct measurement of the plasma response to electrostatic ion waves

International Nuclear Information System (INIS)

Sarfaty, M.; DeSouza-Machado, S.; Skiff, F.

1995-01-01

Plasma wave-wave and wave-particle interactions are studied in a linear magnetized plasma. The relatively quiet plasma is produced by an argon gas-discharge. The plasma density is n e ≅ 10 9 cm -3 and the electron/ion temperatures are T e ≅ 5eV and T i = 0.05eV. A grid and a four ring antenna, both mounted on a scanning carriage, are used to launch electrostatic ion waves in the plasma. Laser Induced Fluorescence measurements of both the linear and the nonlinear plasma response to the wave fields are presented. The Vlasov-Poisson equations are used to explain the measured zero, first and second order terms of the ion distribution function in the presence of wave fields. In addition to the broadening (heating) of the ion distribution as the authors increase the wave amplitudes, induced plasma flows are observed both along and across the magnetic field

Soliton shock wave fronts and self-similar discontinuities in dispersion hydrodynamics

International Nuclear Information System (INIS)

Gurevich, A.V.; Meshcherkin, A.P.

1987-01-01

Nonlinear flows in nondissipative dispersion hydrodynamics are examined. It is demonstrated that in order to describe such flows it is necessary to incorporate a new concept: a special discontinuity called a ''self-similar'' discontinuity consisting of a nondissipative shock wave and a powerful slow wave discontinuity in regular hydrodynamics. The ''self similar discontinuity'' expands linearly over time. It is demonstrated that this concept may be introduced in a solution to Euler equations. The boundary conditions of the ''self similar discontinuity'' that allow closure of Euler equations for dispersion hydrodynamics are formulated, i.e., those that replace the shock adiabatic curve of standard dissipative hydrodynamics. The structure of the soliton front and of the trailing edge of the shock wave is investigated. A classification and complete solution are given to the problem of the decay of random initial discontinuities in the hydrodynamics of highly nonisothermic plasma. A solution is derived to the problem of the decay of initial discontinuities in the hydrodynamics of magnetized plasma. It is demonstrated that in this plasma, a feature of current density arises at the point of soliton inversion

Nonlinear wave equation with intrinsic wave particle dualism

International Nuclear Information System (INIS)

Klein, J.J.

1976-01-01

A nonlinear wave equation derived from the sine-Gordon equation is shown to possess a variety of solutions, the most interesting of which is a solution that describes a wave packet travelling with velocity usub(e) modulating a carrier wave travelling with velocity usub(c). The envelop and carrier wave speeds agree precisely with the group and phase velocities found by de Broglie for matter waves. No spreading is exhibited by the soliton, so that it behaves exactly like a particle in classical mechanics. Moreover, the classically computed energy E of the disturbance turns out to be exactly equal to the frequency ω of the carrier wave, so that the Planck relation is automatically satisfied without postulating a particle-wave dualism. (author)

Arguments for fundamental emission by the parametric process L yields T + S in interplanetary type III bursts. [langmuir, electromagnetic, ion acoustic waves (L, T, S)

Science.gov (United States)

Cairns, I. H.

1984-01-01

Observations of low frequency ion acoustic-like waves associated with Langmuir waves present during interplanetary Type 3 bursts are used to study plasma emission mechanisms and wave processes involving ion acoustic waves. It is shown that the observed wave frequency characteristics are consistent with the processes L yields T + S (where L = Langmuir waves, T = electromagnetic waves, S = ion acoustic waves) and L yields L' + S proceeding. The usual incoherent (random phase) version of the process L yields T + S cannot explain the observed wave production time scale. The clumpy nature of the observed Langmuir waves is vital to the theory of IP Type 3 bursts. The incoherent process L yields T + S may encounter difficulties explaining the observed Type 3 brightness temperatures when Langmuir wave clumps are incorporated into the theory. The parametric process L yields T + S may be the important emission process for the fundamental radiation of interplanetary Type 3 bursts.

Ionospheric shock waves triggered by rockets

Directory of Open Access Journals (Sweden)

C. H. Lin

2014-09-01

Full Text Available This paper presents a two-dimensional structure of the shock wave signatures in ionospheric electron density resulting from a rocket transit using the rate of change of the total electron content (TEC derived from ground-based GPS receivers around Japan and Taiwan for the first time. From the TEC maps constructed for the 2009 North Korea (NK Taepodong-2 and 2013 South Korea (SK Korea Space Launch Vehicle-II (KSLV-II rocket launches, features of the V-shaped shock wave fronts in TEC perturbations are prominently seen. These fronts, with periods of 100–600 s, produced by the propulsive blasts of the rockets appear immediately and then propagate perpendicularly outward from the rocket trajectory with supersonic velocities between 800–1200 m s−1 for both events. Additionally, clear rocket exhaust depletions of TECs are seen along the trajectory and are deflected by the background thermospheric neutral wind. Twenty minutes after the rocket transits, delayed electron density perturbation waves propagating along the bow wave direction appear with phase velocities of 800–1200 m s−1. According to their propagation character, these delayed waves may be generated by rocket exhaust plumes at earlier rocket locations at lower altitudes.

Stabilized lasers for advanced gravitational wave detectors

International Nuclear Information System (INIS)

Willke, B; Danzmann, K; Kwee, P; Seifert, F; Frede, M; Kracht, D; Puncken, O; Schulz, B; Veltkamp, C; Wagner, S; Wessels, P; Winkelmann, L; King, P; Savage, R L Jr

2008-01-01

Second generation gravitational wave detectors require high power lasers with more than 100 W of output power and with very low temporal and spatial fluctuations. To achieve the demanding stability levels required, low noise techniques and adequate control actuators have to be part of the high power laser design. In addition feedback control and passive noise filtering is used to reduce the fluctuations in the so-called prestabilized laser system (PSL). In this paper, we discuss the design of a 200 W PSL which is under development for the Advanced LIGO gravitational wave detector and will present the first results. The PSL noise requirements for advanced gravitational wave detectors will be discussed in general and the stabilization scheme proposed for the Advanced LIGO PSL will be described

A cost-utility analysis of lung cancer screening and the additional benefits of incorporating smoking cessation interventions.

Directory of Open Access Journals (Sweden)

Andrea C Villanti

Full Text Available A 2011 report from the National Lung Screening Trial indicates that three annual low-dose computed tomography (LDCT screenings for lung cancer reduced lung cancer mortality by 20% compared to chest X-ray among older individuals at high risk for lung cancer. Discussion has shifted from clinical proof to financial feasibility. The goal of this study was to determine whether LDCT screening for lung cancer in a commercially-insured population (aged 50-64 at high risk for lung cancer is cost-effective and to quantify the additional benefits of incorporating smoking cessation interventions in a lung cancer screening program.The current study builds upon a previous simulation model to estimate the cost-utility of annual, repeated LDCT screenings over 15 years in a high risk hypothetical cohort of 18 million adults between age 50 and 64 with 30+ pack-years of smoking history. In the base case, the lung cancer screening intervention cost $27.8 billion over 15 years and yielded 985,284 quality-adjusted life years (QALYs gained for a cost-utility ratio of $28,240 per QALY gained. Adding smoking cessation to these annual screenings resulted in increases in both the costs and QALYs saved, reflected in cost-utility ratios ranging from $16,198 per QALY gained to $23,185 per QALY gained. Annual LDCT lung cancer screening in this high risk population remained cost-effective across all sensitivity analyses.The findings of this study indicate that repeat annual lung cancer screening in a high risk cohort of adults aged 50-64 is highly cost-effective. Offering smoking cessation interventions with the annual screening program improved the cost-effectiveness of lung cancer screening between 20% and 45%. The cost-utility ratios estimated in this study were in line with other accepted cancer screening interventions and support inclusion of annual LDCT screening for lung cancer in a high risk population in clinical recommendations.

ALFVEN WAVES IN A PARTIALLY IONIZED TWO-FLUID PLASMA

Energy Technology Data Exchange (ETDEWEB)

Soler, R.; Ballester, J. L.; Terradas, J. [Departament de Fisica, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Carbonell, M., E-mail: roberto.soler@uib.es, E-mail: joseluis.ballester@uib.es, E-mail: jaume.terradas@uib.es, E-mail: marc.carbonell@uib.es [Departament de Matematiques i Informatica, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain)

2013-04-20

Alfven waves are a particular class of magnetohydrodynamic waves relevant in many astrophysical and laboratory plasmas. In partially ionized plasmas the dynamics of Alfven waves is affected by the interaction between ionized and neutral species. Here we study Alfven waves in a partially ionized plasma from the theoretical point of view using the two-fluid description. We consider that the plasma is composed of an ion-electron fluid and a neutral fluid, which interact by means of particle collisions. To keep our investigation as general as possible, we take the neutral-ion collision frequency and the ionization degree as free parameters. First, we perform a normal mode analysis. We find the modification due to neutral-ion collisions of the wave frequencies and study the temporal and spatial attenuation of the waves. In addition, we discuss the presence of cutoff values of the wavelength that constrain the existence of oscillatory standing waves in weakly ionized plasmas. Later, we go beyond the normal mode approach and solve the initial-value problem in order to study the time-dependent evolution of the wave perturbations in the two fluids. An application to Alfven waves in the low solar atmospheric plasma is performed and the implication of partial ionization for the energy flux is discussed.

InP Devices For Millimeter-Wave Monolithic Circuits

Science.gov (United States)

Binari, S. C.; Neidert, R. E.; Dietrich, H. B.

1989-11-01

High efficiency, mm-wave operation has been obtained from lateral transferred-electron devices (TEDs) designed with a high resistivity region located near the cathode contact. At 29.9 GHz, a CW power output of 29.1 mW with a conversion efficiency of 6.7% has been achieved with cavity-tuned discrete devices. This result represents the highest power output and efficiency of a lateral TED in this frequency range. The lateral devices also had a CW power output of 0.4 mW at 98.5 GHz and 0.9 mW at 75.2 GHz. In addition, a monolithic oscillator incorporating the lateral TED has been demonstrated at 79.9 GHz. InP Schottky-barrier diodes have been fabricated using selective MeV ion implantation into semi-insulating InP substrates. Using Si implantation with energies of up to 6.0 MeV, n+ layers as deep as 3 μm with peak carrier concentrations of 2 x 1018 cm-3 have been obtained. These devices have been evaluated as mixers and detectors at 94 GHz and have demonstrated a conversion loss of 7.6 dB and a zero-bias detector sensitivity as high as 400 mV/mW.

Technological and Economic Aspects of Wave Energy Harvesting

Directory of Open Access Journals (Sweden)

Rahul Basu

2018-01-01

Full Text Available The geographical regions contiguous to the Indian Ocean, Bay of Bengal and the Arabian Sea are prone to natural disasters and poor electric supply especially in rural and hard to reach coastal regions. Utilization of ocean resources for power generation such as tidal, thermal solar and wind for energy need to be incorporated in a broad framework for the region. Development of ocean-based energy systems can be integrated with early warning networks linked by satellite which can give a few hours to days warning to help mitigate the severity of natural disasters on human life. Ocean-based electricity extraction has; however, remained elusive for various reasons. Interest in these systems resumed after the oil crisis of the 1970’s, but was uncoordinated. Extraction of ocean energy from the kinetic energy of waves and ocean currents depends on various mechanical devices with variable efficiencies. Apart from the efficiency, one must match the output phase of the feeder waveforms with that of the electrical grid. Also, the wavelengths of the typical wave are of the order of a few meters, the interception of which requires large devices. The mechanical efficiency of the turbine extraction system is further limited by the flow momentum considerations. Some applications and their implementation are looked at, specifically with reference to the difficulties of implementation in the region, and other factors like economic efficiency (rate of returns in place of mechanical efficiency. Individual wave energy harvesters are thus bound to suffer from inefficiencies and it may be beneficial to use wave farm configurations from the point of view of the randomness of wave motion, the large wavelengths, and the added advantage of averaging fluctuations from large numbers of generators.

Emergence of target waves in paced populations of cyclically competing species

Energy Technology Data Exchange (ETDEWEB)

Jiang Luoluo; Zhou Tao; Wang Binghong [Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China); Perc, Matjaz [Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Koroska cesta 160, SI-2000 Maribor (Slovenia); Huang Xin [Department of Physics, University of Science and Technology of China, Hefei 230026 (China)], E-mail: jiangluo@mail.ustc.edu.cn, E-mail: zhutou@ustc.edu, E-mail: matjaz.perc@uni-mb.si, E-mail: bhwang@ustc.edu.cn

2009-10-15

We investigate the emergence of target waves in a cyclic predator-prey model incorporating a periodic current of the three competing species in a small area situated at the center of a square lattice. The periodic current acts as a pacemaker, trying to impose its rhythm on the overall spatiotemporal evolution of the three species. We show that the pacemaker is able to nucleate target waves that eventually spread across the whole population, whereby three routes leading to this phenomenon can be distinguished depending on the mobility of the three species and the oscillation period of the localized current. First, target waves can emerge due to the synchronization between the periodic current and oscillations of the density of the three species on the spatial grid. The second route is similar to the first, the difference being that the synchronization sets in only intermittently. Finally, the third route toward target waves is realized when the frequency of the pacemaker is much higher than that characterizing the oscillations of the overall density of the three species. By considering the mobility and frequency of the current as variable parameters, we thus provide insights into the mechanisms of pattern formation resulting from the interplay between local and global dynamics in systems governed by cyclically competing species.

Dust acoustic solitary waves and double layers in a dusty plasma with two-temperature trapped ions

International Nuclear Information System (INIS)

El-Labany, S.K.; El-Taibany, W.F.; Mamun, A.A.; Moslem, Waleed M.

2004-01-01

The combined effects of trapped ion distribution, two-ion-temperature, dust charge fluctuation, and dust fluid temperature are incorporated in the study of nonlinear dust acoustic waves in an unmagnetized dusty plasma. It is found that, owing to the departure from the Boltzmann ion distribution to the trapped ion distribution, the dynamics of small but finite amplitude dust acoustic waves is governed by a modified Korteweg-de Vries equation. The latter admits a stationary dust acoustic solitary wave solution, which has stronger nonlinearity, smaller amplitude, wider width, and higher propagation velocity than that involving adiabatic ions. The effect of two-ion-temperature is found to provide the possibility for the coexistence of rarefactive and compressive dust acoustic solitary structures and double layers. Although the dust fluid temperature increases the amplitude of the small but finite amplitude solitary waves, the dust charge fluctuation does the opposite effect. The present investigation should help us to understand the salient features of the nonlinear dust acoustic waves that have been observed in a recent numerical simulation study

Millimeter wave and terahertz wave transmission characteristics in plasma

International Nuclear Information System (INIS)

Ma Ping; Qin Long; Chen Weijun; Zhao Qing; Shi Anhua; Huang Jie

2013-01-01

An experiment was conducted on the shock tube to explore the transmission characteristics of millimeter wave and terahertz wave in high density plasmas, in order to meet the communication requirement of hypersonic vehicles during blackout. The transmission attenuation curves of millimeter wave and terahertz wave in different electron density and collision frequency were obtained. The experiment was also simulated by auxiliary differential equation finite-difference time-domain (ADE-FDTD) methods. The experimental and numerical results show that the transmission attenuation of terahertz wave in the plasma is smaller than that of millimeter wave under the same conditions. The transmission attenuation of terahertz wave in the plasma is enhanced with the increase of electron density. The terahertz wave is a promising alternative to the electromagnetic wave propagation in high density plasmas. (authors)

Underwater noise from a wave energy converter

DEFF Research Database (Denmark)

Tougaard, Jakob

A recent addition to the anthropogenic sources of underwater noise is offshore wave energy converters. Underwater noise was recorded from the Wavestar wave energy converter located at Hastholm, Denmark (57°7.73´N, 8°37.23´E). The Wavestar is a full-scale test and demonstration converter...... in full operation and start and stop of the converter. Median broad band (10 Hz – 20 kHz) sound pressure level (Leq) was 123 dB re. 1 Pa, irrespective of status of the wave energy converter (stopped, running or starting/stopping). The most pronounced peak in the third-octave spectrum was in the 160 Hz...... significant noise above ambient could be detected above the 250 Hz band. The absolute increase in noise above ambient was very small. L50 third-octave levels in the four bands with the converter running were thus only 1-2 dB above ambient L50 levels. The noise recorded 25 m from the wave energy converter...

Terahertz-wave differential detection based on simultaneous dual-wavelength up-conversion

Directory of Open Access Journals (Sweden)

Yuma Takida

2017-03-01

Full Text Available We report a terahertz (THz-wave differential detection based on simultaneous dual-wavelength up-conversion in a nonlinear optical MgO:LiNbO3 crystal with optical and electronic THz-wave sources. The broadband parametric gain and noncollinear phase-matching of MgO:LiNbO3 provide efficient conversion from superposed THz waves to spatially distributed near-infrared (NIR beams to function as a dispersive THz-wave spectrometer without any additional dispersive element. We show that the μW-level THz waves from two independent sources, a 0.78-THz injection-seeded THz-wave parametric generator (is-TPG and a 1.14-THz resonant tunneling diode (RTD, are simultaneously up-converted to two NIR waves and then detected with two NIR photodetectors. By applying a balanced detection scheme to this dual-frequency detection, we demonstrate THz-wave differential imaging of maltose and polyethylene pellets in the transmission geometry. This dual-wavelength detection is applicable to more than three frequencies and broadband THz-wave radiation for real-time THz-wave spectroscopic detection and imaging.

Frequency modulation at a moving material interface and a conservation law for wave number. [acoustic wave reflection and transmission

Science.gov (United States)

Kleinstein, G. G.; Gunzburger, M. D.

1976-01-01

An integral conservation law for wave numbers is considered. In order to test the validity of the proposed conservation law, a complete solution for the reflection and transmission of an acoustic wave impinging normally on a material interface moving at a constant speed is derived. The agreement between the frequency condition thus deduced from the dynamic equations of motion and the frequency condition derived from the jump condition associated with the integral equation supports the proposed law as a true conservation law. Additional comparisons such as amplitude discontinuities and Snells' law in a moving media further confirm the stated proposition. Results are stated concerning frequency and wave number relations across a shock front as predicted by the proposed conservation law.

75 FR 48353 - United States Pharmacopeial Convention; Filing of Food Additive Petition

Science.gov (United States)

2010-08-10

...] United States Pharmacopeial Convention; Filing of Food Additive Petition AGENCY: Food and Drug.... Pharmacopeial Convention has filed a petition proposing that the food additive regulations that incorporate by... that a food additive petition (FAP 0A4782) has been filed by U.S. Pharmacopeial Convention, 12601...

Coupling electromagnetic pulse-shaped waves into wire-like interconnection structures with a non-linear protection – Time domain calculations by the PEEC method

Directory of Open Access Journals (Sweden)

G. Wollenberg

2004-01-01

Full Text Available An interconnection system whose loads protected by a voltage suppressor and a low-pass filter against overvoltages caused by coupling pulse-shaped electromagnetic waves is analyzed. The external wave influencing the system is assumed as a plane wave with HPM form. The computation is provided by a full-wave PEEC model for the interconnection structure incorporated in the SPICE code. Thus, nonlinear elements of the protection circuit can be included in the calculation. The analysis shows intermodulation distortions and penetrations of low frequency interferences caused by intermodulations through the protection circuits. The example examined shows the necessity of using full-wave models for interconnections together with non-linear circuit solvers for simulation of noise immunity in systems protected by nonlinear devices.

Wave Generation Theory

DEFF Research Database (Denmark)

Frigaard, Peter; Høgedal, Michael; Christensen, Morten

The intention of this manual is to provide some formulas and techniques which can be used for generating waves in hydraulic laboratories. Both long crested waves (2-D waves) and short crested waves (3-D waves) are considered.......The intention of this manual is to provide some formulas and techniques which can be used for generating waves in hydraulic laboratories. Both long crested waves (2-D waves) and short crested waves (3-D waves) are considered....