bluuebunny/crossref_metadata_2025 huggingface dataset:
Seabed Shear Stress Spectrum for Very Rough Beds
Authors: Myrhaug Dag , Holmedal Lars Erik
Published: July 2010

The spectrum of seabed shear stresses at beds with large roughness beneath ocean surface waves in finite water depth is derived by using the wave friction factor for large roughness. It is expressed in terms of the transfer function between the waves at the surface and the shear stress at the bed, and the wave spectrum in finite water depth, which is obtained by multiplying the deep water wave spectrum with a depth correction factor. The seabed shear stress spectrum for laminar flow, which is of practical interest for flow over muds, is also given in order to compare with the rough turbulent case. Examples are included to illustrate the applicability of the seabed shear stress spectrum for practical purposes using data typical for field conditions, both for very rough beds and mud beds.
Vibrational spectra of quantum dots formed by Langmuir–Blodgett technique
Authors: Milekhin A. , Sveshnikova L. , Duda T. , Surovtsev N. , Adichtchev S. , Ding L. , Zahn D. R. T.
Published: July 2010

Phonon spectra of CdS, ZnS, PbS, CuS, Ag2S, and ZnO quantum dots formed by using the Langmuir–Blodgett technology are investigated by Raman and infrared spectroscopies. The Raman spectra of structures show peaks corresponding to the scattering by longitudinal and transverse optical (LO and TO) phonons localized in quantum dots that confirm the formation of nanocrystals. In addition to TO and LO phonon modes, the modes observed in the IR spectra between the frequency positions of LO and TO phonons are attributed to the surface optical phonons in quantum dots.
Ex situ Ohmic contacts to n-InGaAs
Authors: Baraskar Ashish , Wistey Mark A. , Jain Vibhor , Lobisser Evan , Singisetti Uttam , Burek Greg , Lee Yong Ju , Thibeault Brian , Gossard Arthur , Rodwell Mark
Published: July 2010

The authors report ultralow specific contact resistivity (ρc) in ex situ Ohmic contacts to n-type In0.53Ga0.47As (100) layers, with an electron concentration of 5×1019 cm−3. They present the ρc obtained for molybdenum (Mo) contacts to n-type In0.53Ga0.47As, with the semiconductor surface cleaned by atomic H before metal deposition. The authors compare these data with the ρc obtained for contacts made without atomic H cleaning. After exposure to air during normal device processing, the semiconductor surface was prepared by UV-ozone exposure plus a dilute HCl etch and subsequently exposed to thermally cracked H. Mo contact metal was deposited in an electron beam evaporator without breaking vacuum after H cleaning. Transmission line model measurements showed a contact resistivity of (1.1±0.9)×10−8 Ω cm2 for the Mo/In0.53Ga0.47As interface. This ρc is equivalent to that obtained with in situ Mo contacts [ρc=(1.1±0.6)×10−8 Ω cm2]. Ex situ contacts prepared by UV-ozone exposure plus dilute HCl (without any atomic H exposure) result in ρc=(1.5±1.0)×10−8 Ω cm2.
Electric field induced motion of metallic droplets: Application to submicron contactor
Authors: Dallaporta H. , Prestigiacomo M. , Bedu F. , Tonneau D. , Chatain D. , Sudraud P.
Published: July 2010

This article reports the monitoring of reversible displacement of a gallium droplet on a tungsten submicron wire deposited by focused ion beam from tungsten hexacarbonyl precursor. The authors demonstrate that by applying a voltage to the wire terminals, the internal electric field created along the wire produces the motion of the droplet. Since the matter involved in this displacement is conductive, the authors show that it is possible to build a submicron electrical switch. Contact can be switched on and off between two electrodes separated by a submicron gap, by electrical monitoring the position of the conductive droplet.
An approximate form of the Rayleigh reflection loss and its phase: Application to reverberation calculation
Authors: Harrison Chris H.
Published: July 2010

A useful approximation to the Rayleigh reflection coefficient for two half-spaces composed of water over sediment is derived. This exhibits dependence on angle that may deviate considerably from linear in the interval between grazing and critical. It shows that the non-linearity can be expressed as a separate function that multiplies the linear loss coefficient. This non-linearity term depends only on sediment density and does not depend on sediment sound speed or volume absorption. The non-linearity term tends to unity, i.e., the reflection loss becomes effectively linear, when the density ratio is about 1.27. The reflection phase in the same approximation leads to the well-known “effective depth” and “lateral shift.” A class of closed-form reverberation (and signal-to-reverberation) expressions has already been developed [C. H. Harrison, J. Acoust. Soc. Am. 114, 2744–2756 (2003); C. H. Harrison, J. Comput. Acoust. 13, 317–340 (2005); C. H. Harrison, IEEE J. Ocean. Eng. 30, 660–675 (2005)]. The findings of this paper enable one to convert these reverberation expressions from simple linear loss to more general reflecting environments. Correction curves are calculated in terms of sediment density. These curves are applied to a test case taken from a recent ONR-funded Reverberation Workshop.
Suppression of broadband noise radiated by a low-speed fan in a duct
Authors: Huang L. , Ma X. , Feng L. G.
Published: July 2010

Attenuation of ducted fan noise remains a technical challenge in the low frequency range as traditional duct lining becomes ineffective. This study proposes a reactive method to suppress the sound radiation from an axial-flow fan. The method is particularly effective in the low frequency region and covers a broad band. Its effect is derived from two mechanisms. One is the reduction in the confining effects of duct walls when the duct radius is increased; the other is the acoustic interference between the direct radiation from the fan and reflections by the duct junctions. This interference is always destructive for axial dipoles when the frequency approaches zero. This performance differs from normal passive control methods, which become totally ineffective toward zero frequency. An approximate plane-wave theory explains the essential physics of the method, and its quantitative prediction is found to agree well with a full numerical simulation using a spectral method of Chebyshev collocation. The latter is validated by experiment using an axial-flow fan in a duct of finite length. Broadband noise reduction is achieved while the flow speed is kept unchanged. Practical difficulties of implementation for a fan with high pressure increase are discussed.
Pitch perception for mixtures of spectrally overlapping harmonic complex tones
Authors: Micheyl Christophe , Keebler Michael V. , Oxenham Andrew J.
Published: July 2010

This study measured difference limens for fundamental frequency (DLF0s) for a target harmonic complex in the presence of a simultaneous spectrally overlapping harmonic masker. The resolvability of the target harmonics was manipulated by bandpass filtering the stimuli into a low (800–2400 Hz) or high (1600–3200 Hz) spectral region, using different nominal F0s for the targets (100, 200, and 400 Hz), and different masker F0s (0, +9, or −9 semitones) relative to the target. Three different modes of masker presentation, relative to the target, were tested: ipsilateral, contralateral, and dichotic, with a higher masker level in the contralateral ear. Ipsilateral and dichotic maskers generally caused marked elevations in DLF0s compared to both the unmasked and contralateral masker conditions. Analyses based on excitation patterns revealed that ipsilaterally masked F0 difference limens were small (<2%) only when the excitation patterns evoked by the target-plus-masker mixture contained several salient (>1 dB) peaks at or close to target harmonic frequencies, even though these peaks were rarely produced by the target alone. The findings are discussed in terms of place- or place-time mechanisms of pitch perception.
Fixed time versus fixed range reverberation calculation: Analytical solution
Authors: Harrison Chris H. , Ainslie Michael A.
Published: July 2010

Reverberation is commonly calculated by estimating the propagation loss to and from an elementary area, defined by transmitted pulse length and beam width, and treating the resulting backscatter from the area as a function of its range. In reality reverberation is strictly a function of time and contributions for a given time come from many ranges. Closed-form solutions are given for reverberation calculated both at fixed range and at fixed time isovelocity water and some variants of Lambert’s law and linear reflection loss with an abrupt critical angle. These are derived by considering the shape of the two-way scattered multipath pulse envelope from a point scatterer. The ratio of these two solutions is shown to depend on the dominant propagation angle spread for the particular range or time. The ratio is largest at intermediate ranges (though typically less than 1 dB) and depends explicitly on the critical angle. At longer ranges mode-stripping reduces the propagation angle spread and the ratio reduces ultimately to unity. At short range the ratio is also close to unity although interpreting it requires care.
Improving the statistical wave field description using the Waterhouse correction
Authors: Prager Jens , Petersson Bjoern A. T.
Published: July 2010

The diffuse field assumption employed in basic statistical energy analysis (SEA) and in statistical room acoustics is violated for source and receiver positions close to boundaries or discontinuities. A simple approach is proposed to include the correction initially suggested by Waterhouse based on spherical Bessel functions in SEA predictions for rectangular rooms. With this modification the SEA results will be augmented by a position dependence and an additional frequency dependence. The approach is applied and demonstrated also for plate-like structures with different boundary conditions. An analytical solution is shown for the corner position on a simply supported plate and for edge positions on plates with more complex boundary conditions. The validity of the approach is confirmed by means of comparisons with modal analysis and finite element calculations.
Temporal integration of vowel periodicity in the auditory cortex
Authors: Yrttiaho Santeri , Tiitinen Hannu , Alku Paavo , Miettinen Ismo , May Patrick J. C.
Published: July 2010

Cortical sensitivity to the periodicity of speech sounds has been evidenced by larger, more anterior responses to periodic than to aperiodic vowels in several non-invasive studies of the human brain. The current study investigated the temporal integration underlying the cortical sensitivity to speech periodicity by studying the increase in periodicity-specific cortical activation with growing stimulus duration. Periodicity-specific activation was estimated from magnetoencephalography as the differences between the N1m responses elicited by periodic and aperiodic vowel stimuli. The duration of the vowel stimuli with a fundamental frequency (F0=106 Hz) representative of typical male speech was varied in units corresponding to the vowel fundamental period (9.4 ms) and ranged from one to ten units. Cortical sensitivity to speech periodicity, as reflected by larger and more anterior responses to periodic than to aperiodic stimuli, was observed when stimulus duration was 3 cycles or more. Further, for stimulus durations of 5 cycles and above, response latency was shorter for the periodic than for the aperiodic stimuli. Together the current results define a temporal window of integration for the periodicity of speech sounds in the F0 range of typical male speech. The length of this window is 3–5 cycles, or 30–50 ms.
Thermoacoustic power conversion using a piezoelectric transducer
Authors: Jensen Carl , Raspet Richard
Published: July 2010

The predicted efficiency of a simple thermoacoustic waste heat power conversion device has been investigated as part of a collaborative effort combining a thermoacoustic engine with a piezoelectric transducer. Symko et al. [Microelectron. J. 35, 185–191 (2004)] at the University of Utah built high frequency demonstration engines for this application, and Lynn [ASMDC report, accession number ADA491030 (2008)] at the University of Washington designed and built a high efficiency piezoelectric unimorph transducer for electroacoustic conversion. The design presented in this paper is put forward to investigate the potential of a simple high frequency, air filled, standing wave thermoacoustic device to be competitive with other small generator technologies such as thermoelectric devices. The thermoacoustic generator is simulated using a low-amplitude approximation for thermoacoustics and the acoustic impedance of the transducer is modeled using an equivalent circuit model calculated from the transducer’s mechanical and electrical properties. The calculations demonstrate that a device performance of around 10% of Carnot efficiency could be expected from the design which is competitive with currently available thermoelectric generators.
Acoustical and vibrometry analysis of a large Balinese gamelan gong
Authors: Krueger David W. , Gee Kent L. , Grimshaw Jeremy
Published: July 2010

The Balinese gamelan gong ageng wadon produces distinct acoustic beating (called ombak) when struck. This phenomenon is explored using both acoustical and vibrometry measurements. The measurements have revealed the beating has two sources. First, there are four closely spaced modes that, given their asymmetric vibration patterns, might have been deliberately hammered into the response of the gong. Second, and more importantly, a nonlinear structural response of the gong causes the fundamental axisymmetric mode to produce harmonics. The second harmonic of the fundamental mode interacts with the second axisymmetric mode with relative amplitudes such that strong beating is produced.
Influence of the accommodation coefficient on nonlinear bubble oscillations
Authors: Fuster Daniel , Hauke Guillermo , Dopazo Cesar
Published: July 2010

This paper numerically investigates the effect of mass transfer processes on spherical single bubble dynamics using the Hertz–Langmuir–Knudsen approximation for the mass flux across the interface. Bubble behavior, with and without mass transfer, is studied for different values of pressure wave amplitude and frequency, as well as initial bubble radius. Whereas mass transfer processes do not seem to play a significant role on the bubble response for pressure amplitudes smaller than 0.9 atm, they appear to have an important effect when the amplitude is greater than or equal to 1 atm. For the later case, where the minimum liquid pressure reaches values around its vapor pressure, the importance of mass transfer depends on frequency. For frequencies in the 103–105 Hz range and initial bubble radii of the order of tens of microns, bubble implosions with and with no mass transfer are significantly different; smaller radii display a lower sensitivity. In this regime, accurate model predictions must, therefore, carefully select the correct value of the accommodation coefficient. For frequencies greater than 105 Hz, as a first approximation mass transfer can be ignored.
Displacement analysis of diagnostic ultrasound backscatter: A methodology for characterizing, modeling, and monitoring high intensity focused ultrasound therapy
Authors: Speyer Gavriel , Kaczkowski Peter J. , Brayman Andrew A. , Crum Lawrence A.
Published: July 2010

Accurate monitoring of high intensity focused ultrasound (HIFU) therapy is critical for widespread clinical use. Pulse-echo diagnostic ultrasound (DU) is known to exhibit temperature sensitivity through relative changes in time-of-flight between two sets of radio frequency (RF) backscatter measurements, one acquired before and one after therapy. These relative displacements, combined with knowledge of the exposure protocol, material properties, heat transfer, and measurement noise statistics, provide a natural framework for estimating the administered heating, and thereby therapy. The proposed method, termed displacement analysis, identifies the relative displacements using linearly independent displacement patterns, or modes, each induced by a particular time-varying heating applied during the exposure interval. These heating modes are themselves linearly independent. This relationship implies that a linear combination of displacement modes aligning the DU measurements is the response to an identical linear combination of heating modes, providing the heating estimate. Furthermore, the accuracy of coefficient estimates in this approximation is determined a priori, characterizing heating, thermal dose, and temperature estimates for any given protocol. Predicted performance is validated using simulations and experiments in alginate gel phantoms. Evidence for a spatially distributed interaction between temperature and time-of-flight changes is presented.
Non-Hertzian behavior in binary collisions of plastic balls derived from impact acoustics
Authors: Riner Joshua , Petculescu Andi
Published: July 2010

This paper presents slight deviations from Hertz’s impact law, inferred from acoustic signatures of polypropylene ball collisions. An impact acoustics model is used to fit the acoustic data. The model is built upon a generalized relationship between impact force (F) and deformation (ξ) of the form F=κξα. Agreement with experiment is reached when α and κ differ from Hertz’s values by −6.25% and +1%, respectively. The difference is ascribable to non-idealities such as slight material inhomogeneities, impact-point asymmetry, plasticity etc. Also, the collision energy released as sound, which is usually dismissed as negligible, is derived from data fitting. The acoustic-to-incident energy ratio, dependent on impact duration, is constrained to be on the order of 100 ppm.
Stage acoustics for symphony orchestras in concert halls
Authors: Dammerud Jens Jo/rgen
Published: July 2010

The main goals for this study were to better understand what are the acoustic conditions physically within a symphony orchestra on concert hall stages, how these physical conditions affect the players and ultimately how to design venues suitable for symphony orchestras. This was investigated through questionnaire surveys and dialogue with musicians, scale and computer modelling and measurements of existing stages. The results from the orchestra collaborations indicate that the impressions of acoustic conditions are related to complex perceptual effects. When relating these effects to acoustic conditions, a narrow and high stage enclosure with the stage highly exposed to the main auditorium appears most beneficial. Existing methods for assessing the stage acoustically by use of omnidirectional transducers without the orchestra present were found to have only limited relevance to perceived conditions. New methods and objective architectural measures have been proposed. The architectural measures successfully discriminate the most preferred from the least preferred stages of purpose-built concert halls. The results from judgements of existing stages support the finding of a narrow and high stage enclosure with a highly exposed stage being most beneficial. How to improve the assessment of acoustic conditions on stage is discussed. Copies of the thesis written in English can be obtained from Jens Jo/rgen Dammerud. E-mail address: jjdamm@gmail.com. 4
Long-range underwater vocalizations of the crabeater seal (Lobodon carcinophaga)
Authors: Klinck Holger , Mellinger David K. , Klinck Karolin , Hager Julia , Kindermann Lars , Boebel Olaf
Published: July 2010

This study provides a comprehensive description of the acoustic characteristics of the predominant long-range underwater vocalizations of the crabeater seal, Lobodon carcinophaga, derived from stationary and continuous long-term recordings obtained in the Southern Ocean in 2007. Visual screening of data recorded between 1 October and 15 December 2007 indicates that the principal period of vocal activity of the crabeater seal is the latter part of October and all of November, coinciding with the breeding season of this species. Two call types were identified during this period: the low moan call, which has been described in previous studies and the high moan call, a call type newly described here. Out of 17 052 manually extracted crabeater seal calls, high-quality recordings of 152 low moans and 86 high moans with a signal-to-noise ratio exceeding 15 dB were selected and call-specific acoustic features were determined. While the mean duration of the two call types was comparable (∼2.5 s), the high moan occurred at notably higher frequencies (1000–4900 Hz) than the low moan (260–2500 Hz). This study provides baseline information necessary to develop automated detection algorithms to facilitate systematic screening of extended data sets for crabeater seal vocalizations.
Vibro-acoustic characteristics of an Aoyama Amphion concert harp
Authors: Daltrop Shira , Kotlicki Andrzej , Waltham Chris
Published: July 2010

The mechanical admittance of the soundboards of four full-size concert harps from three manufacturers was measured, and the results show that there is little variation between them. More detailed vibro-acoustic data were then obtained for an Aoyama Amphion harp. Analysis of these data show that the individual soundholes amplify the radiated sound in successive frequency bands associated with the modal frequencies of the soundboard. The lower holes tend to contribute at the lower end of the frequency scale, and the higher holes at the higher end of the scale.
Tracking near-surface atmospheric conditions using an infrasound network
Authors: Marcillo O. , Johnson J. B.
Published: July 2010

Continuous volcanic infrasound signal was recorded on a three-microphone network at Kilauea in July 2008 and inverted for near-surface horizontal winds. Inter-station phase delays, determined by signal cross-correlation, vary by up to 4% and are attributable to variable atmospheric conditions. The results suggest two predominant weather regimes during the study period: (1) 6–9 m/s easterly trade winds and (2) lower-intensity 2–5 m/s mountain breezes from Mauna Loa. The results demonstrate the potential of using infrasound for tracking local averaged meteorological conditions, which has implications for modeling plume dispersal and quantifying gas flux.
The role of segmentation difficulties in speech-in-speech understanding in older and hearing-impaired adults
Authors: Woodfield Alexandra , Akeroyd Michael A.
Published: July 2010

Older people often complain of difficulties in understanding speech in noisy circumstances. The current study tested the hypothesis that problems segmenting speech may contribute to these difficulties. Segmentation ability was measured in young normal-hearing, older normal-hearing and older hearing-impaired listeners. Listeners were presented with sentences in competing speech and resultant misperceptions were analyzed in terms of their accordance with the metrical segmentation strategy. While strong support for this strategy was indicated, no difference in the use of this strategy was found across the three listener groups, suggesting older listeners were unlikely to be experiencing segmentation difficulties at the sub-lexical level.
Effect of the presence and size of a localized nonlinear source in concrete
Authors: Zardan J.-P. , Payan C. , Garnier V. , Salin J.
Published: July 2010

The aim of the present letter is to identify the contribution of a macroscopic source of elastic nonlinearity in concrete, a medium which by nature is nonlinear, and belongs to the nonlinear mesoscopic class of materials. The influence of real, localized macro-cracks is characterized with respect to the intrinsic nonlinearity of the material. The influence of the size of the source on the amplitude of the measured nonlinearity is qualitatively demonstrated. A comparison is made between the changes in linear and nonlinear parameters.
Synchronous auditory nerve activity in the carboplatin-chinchilla model of auditory neuropathy
Authors: Cowper-Smith C. D. , Dingle R. N. , Guo Y. , Burkard R. , Phillips D. P.
Published: July 2010

Two hallmark features of auditory neuropathy (AN) are normal outer hair cell function in the presence of an absent/abnormal auditory brainstem response (ABR). Studies of human AN patients are unable to determine whether disruption of the ABR is the result of a reduction of neural input, a loss of auditory nerve fiber (ANF) synchrony, or both. Neurophysiological data from the carboplatin model of AN reveal intact neural synchrony in the auditory nerve and inferior colliculus, despite significant reductions in neural input. These data suggest that (1), intact neural synchrony is available to support an ABR following carboplatin treatment and, (2), impaired spike timing intrinsic to neurons is required for the disruption of the ABR observed in human AN.
Oxygen Isotope Geochemistry of Submarine Greenstones
Authors: Muehlenbachs K. , Clayton R. N.
Published: July 2010

Most submarine greenstones recovered from the North Mid-Atlantic Ridge range in δ18O from 2.8 to 6.8‰ (SMOW). An extremely light rock. (δ18O = −7.1‰), was also analyzed, but it might be an ice rafted erratic. The heavier ones, up to 8‰, are probably weathered. On the average, the δ18O of 14 greenstones is slightly lower than that of fresh unmetamorphosed submarine basalt. The 18O fractionations between coexisting metamorphic minerals of the greenstones are consistent with the independently inferred range of metamorphic temperatures of 200–300 °C. The δ18O of the possible metamorphic water can be estimated from this temperature range and the δ18O of the metamorphic minerals to be − 2 to + 2‰. This argues strongly that little or no 'juvenile' water (water outgassed from the mantle) participated directly in the metamorphism. The δ18O data are consistent with the participation of sea water in the metamorphism. Similar conclusions can be drawn from the 18O analyses of a submarine diabase and two gabbros. Disseminated carbonates in the greenstones have δ18C values typically found in carbonatites or partially decarbonated marine limestones.
Le Lien Gravitationnel Terre-Lune à Travers les Ages
Authors: Chevallier Jean-Maurice , Cailleux André
Published: July 2010

The authors expressed the view in 1952 that tidal friction between the earth and moon could account for many features such as alterations in biological rhythms, or tectonic effects of unequalled amplitude throughout geological times and the remote past. Tests for this theory are: (a) It is remarkable that the loss of angular momentum by the earth since the "original" state almost exactly matches the amount required to bring the moon from the earth's equator to its present orbit; (b) Recent observations of daily growth increments in fossil organisms show, at least for the last 400 m.y., that the order of magnitude of the time-scale previously adopted by the authors is satisfactory, the scale having only to be somewhat shortened and the values—theoretical and observed—of the month-to-day ratio are in good concordance.
A Permian Overtoniid Brachiopod in Early Triassic Sediments of Axel Heiberg Island, Canadian Arctic and its Implications on the Permian—Triassic Boundary
Authors: Waterhouse J. B.
Published: July 2010

The ventral valve of an overtoniid productacean brachiopod generally thought to have been restricted to the late Paleozoic Era is described from the Blind Fiord Formation, Axel Heiberg Island, of Griesbachian (Early Triassic) age. It is not clear whether the specimen was derived from Permian rocks or was really of Griesbachian age. The latter appears likely from the fact that no similar specimens are known from underlying Permian. Genuine occurrences of Permian-type brachiopods in early Triassic rocks are rare. Half of the examples reported, from Armenia, Iran, and West Pakistan, are shown here to be dated erroneously, occurring in middle or late Permian rocks misdated as Triassic, Other examples, such as those from Green-land, are probably reworked because the Triassic beds conformably overlie mid-Permian rocks, and contain similar mid-Permian brachiopods, probably reworked from the underlying deposits.
On the Interpretation of Magnetotelluric Data in the Plains of Alberta
Authors: Reddy I. K. , Rankin D.
Published: July 2010

Tensor apparent resistivity values obtained from the magnetotelluric field measurements, in the plains of Alberta indicate a major regional anisotropy. The direction of the major axis of the anisotropy is parallel to the strike of the Rocky Mountains and the sedimentary basin of Western Canada. Results obtained by numerical methods for a two-dimensional geoelectric model support an interpretation of the observed magnetotelluric results, depending on regional structures. The observed polarization parameters of the magnetotelluric fields are also in good agreement with those computed for the two-dimensional model. This study shows that the conclusions based on some earlier magnetotelluric results, which postulated an upper mantle conductivity layer must be treated with strong reservations.
Potassium–Argon Ages of the Eagle Granodiorite, Southern British Columbia
Authors: Roddick J. C. , Farrar E.
Published: July 2010

Eight potassium–argon ages from the Eagle granodiorite of south-central British Columbia indicate that the body was intruded over a period of about 10 m.y. with the predominant intrusive activity occurring 104 m.y. ago. Hydrothermal activity continued at least until 72 m.y. ago.
Muscites eocenicus sp. nov.—a Fossil Moss from the Allenby Formation (Middle Eocene), British Columbia
Authors: Kuc Marian
Published: July 2010

Specimens of Muscites eocenicus sp. nov. were found in a laminated, tuffaceous, silty, and pyroclastic shale with arkosic granule conglomerates in the Allenby Formation (Middle Eocene) near Princeton in southern British Columbia. The fossils, the associated fossil flora, and the rock are described.
Traitement de la fondation de moraine du barrage LG-3
Authors: Paré J. J. , Arès R. , Ghzala A. M.
Published: July 2010

A section of the LG-3 dam, one of the major hydroelectric structures of the James Bay development, is founded on a thick deposit of semi-impervious glacial till. An adequate foundation treatment was necessary to cope with the seepage problem.This paper describes the foundation conditions and the studies leading to the design of the dam on the till deposit, where an upstream blanket and cut off have been combined with a downstream toe drain in the typical cross section. An instrumentation program will allow the monitoring of the behaviour of the dam and its foundation so as to detect any anomaly that might develop. [Journal translation]
Cliff collapse and rock avalanches (sturzstroms) in the Mackenzie Mountains, northwestern Canada
Authors: Eisbacher G. H.
Published: July 2010

Cliff collapse and resulting rock avalanches or sturzstroms have occurred widely in carbonate formations of the Mackenzie Mountains, northwestern Canada. Some of the rock slides are close to a Holocene fault scarp and may be due to past earthquake activity. The Mackenzies are located within an intraplate seismic zone; presently monitored seismic activity may not indicate the maximum level of ground motion that caused failure of large rock slopes during the last 10 000 years. At several localities at least two generations of slide material can be recognized. All major sturzstroms originated by failure above inclined bedding plane surfaces, ranging in dip from 13–40°.The mechanical analysis of dry sturzstroms has to consider two stages: failure and streaming. Failure can occur by either 'sliding' (static friction of about tan 30°) or 'roller bearing' and internal collapse (kinetic friction as low as tan 13°). Streaming is initiated by momentum transfer from the back of a collapsing cliff to its frontal disintegrating portion and facilitated by dispersion of large blocks in finer interstitial material. Prediction of reach or excessive travel distance of dry sturzstroms is not a simple matter and one has to consider the effect of slide mass, fall height, topographic constraints, and lithology. The best method of predicting reach in a potential sturzstrom situation is comparison with documented sturzstroms in similar geologic, climatic, and topographic settings.
Anisotropic behaviour of a sensitive clay
Authors: Yong R. N. , Silvestri V.
Published: July 2010

This paper presents the results of a study carried out to determine the drained stress–strain behaviour of a sensitive clay from St-Louis de Bonsecours (Quebec), tested under conventional axisymmetric (σ′1 > σ′2 = σ′3) and complex true-triaxial (σ′1 ≠ σ′2 ≠ σ′3) stress states.The data reported herein show that, for confining pressures below the preconsolidation pressure of the clay, the influence of cementation bonds and anisotropy results in deviation from the Mohr–Coulomb theory and causes the clay to behave as an anisotropic pseudo-elastic, plastic material. It is shown that constitutive relationships derived from the theories of anisotropic elasticity and plasticity represent very well the mechanical response of the clay.
Geotechnical aspects of iceberg scours on ocean floors
Authors: Chari T. Ramanuja
Published: July 2010

Results of exploratory oil drilling on Canada's eastern offshore are highly encouraging. However, the seasonal presence of icebergs in this area poses a threat to the production platforms as well as the pipelines likely to convey oil and gas. This paper describes a simple analysis for iceberg grounding and scouring of ocean floors. Theoretical and laboratory results are presented and compared with the limited field data available at present.
The influence of aging on the shear strength behaviour of two fine-grained soils
Authors: Allam Mehter Mohamed , Sridharan A.
Published: July 2010

A series of undrained triaxial shear tests was conducted on normally consolidated remoulded black cotton soil and kaolinite, in order to examine the influence of aging on their shear strength behaviour. It was found that apart from an increase in shear strength and brittleness, both soils exhibited an increase in their angles of shearing resistance when aged for a month. The cohesion intercept was found to reduce on aging. The initial tangent modulus increases very significantly (to the extent of even 10 times) especially for black cotton soil after 30 days of aging.
Laboratory simulation of shale expansion by induced gypsum growth
Authors: Lutenegger A. J. , Wollenhaupt N. C. , Handy R. L.
Published: July 2010

Floor samples from an underground limestone mine in Kansas City were studied to determine the susceptibility of the shale to expansion by formation of gypsum. A simplified laboratory consolidometer approach was initiated to give insight into possible preventative measures. Calculations of possible heaving pressures indicate that rock bolting may be a viable method to control expansion.
Ultimate bearing capacity of foundations on a three-layer soil, with special reference to layered sand
Authors: Hanna A. M. , Meyerhof G. G.
Published: July 2010

The authors' previous theory of the ultimate bearing capacity of two-layer soils has been extended to the case of a three-layer soil. The analysis compared well with the results of model tests of strip and circular footings on a three-layer soil.
Viscometric assessment of remoulded sensitive clays
Authors: Bentley S. P.
Published: July 2010

Remoulded samples of sensitive clay, from Gloucester and St. Jean Vianney (SJV), have been assessed by viscometric techniques. The results complement geotechnical and mineralogical data and they permit the differences in sensitivity to be discussed in terms of the remoulded clay properties. The SJV clay (St > 200) exhibits dilatant flow properties and the Gloucester clay(St ~ 20) has Bingham plastic characteristics. The properties of the latter are a function of clay mineralogy and pore-water chemistry; they contribute to the remoulded strength and thereby restrict sensitivity. The response of the clays to a changing chemical environment is monitored; increasing the cation concentration of the pore water transforms the SJV clay to a Bingham plastic; a maximum yield stress for the Gloucester clay is attained at pH ~ 6.5. The correlation between viscometric data and related field investigations suggests that this analytical approach may provide a suitable basis for the fundamental study of soil behaviour, soil characterization, and the design of electrochemical ground treatments.
The undrained strength of some thawed permafrost soils
Authors: Nixon John F. , Hanna Alan J.
Published: July 2010

A large number of undrained shear strengths have been measured for thawed, undrained permafrost samples obtained from the Niglintgak Peninsula area of the Mackenzie Delta, N.W.T. The samples are mostly deltaic silts, with a few clay tills, and cover a wide range of depths, water contents, and frozen density. The undrained shear strengths of the thawed samples have been correlated with water content, frozen density, and sample depth. For these soil types, the strength is shown to decrease to zero at frozen densities of less than about 1670 kg/m3 and at water contents greater than about 35–42%. In the Niglintgak area, the undrained shear strength of the thawed samples below a depth of 10 m becomes relatively constant in the range of 23–43 kPa. This corresponds to a frozen density range of 1780–1870 kg/m3, and previous experience with soils of this nature indicates that the corresponding thaw settlement at these depths would be less than 10%.
MICROSCOPIC APPROACH TO SCATTERING OF UNSTABLE NUCLEI
Authors: YAHIRO MASANOBU , MINOMO KOSHO , OGATA KAZUYUKI , SHIMIZU YOSHIFUMI R. , MATSUMOTO TAKUMA , KOHNO MICHIO
Published: July 2010

This article is composed of three subjects. First, the relation between the method of continuum-discretized coupled channels (CDCC) and the Faddeev theory is clarified to show the validity of CDCC. Second, CDCC is applied to four-body reactions such as (6 He , nn 4 He ) as an example of recent progress in CDCC. Third, we propose a microscopic version of CDCC in which a localized form of the microscopic nucleon-nucleus optical potential is used as an input of CDCC calculation instead of the phenomenological optical potential commonly used. The validity of the Brieva-Rook localization is shown for the proton scattering in a wide incident-energy range.
MICROSCOPIC APPROACH TO ADIABATIC LARGE-AMPLITUDE QUADRUPOLE COLLECTIVE DYNAMICS IN Se ISOTOPES
Authors: HINOHARA NOBUO , SATO KOICHI , NAKATSUKASA TAKASHI , MATSUO MASAYUKI
Published: July 2010

We develop an efficient microscopic method of deriving the five-dimensional quadrupole collective Hamiltonian on the basis of the adiabatic self-consistent collective coordinate method. We illustrate its usefulness by applying it to the oblate-prolate shape coexistence/mixing phenomena and anharmonic vibrations in Se isotopes.
THE 6He+6He AND α+8He CLUSTER STATES IN 12Be VIA α-INELASTIC SCATTERING
Authors: SAITO A. , SHIMOURA S. , MINEMURA T. , MATSUYAMA Y. U. , BABA H. , AOI N. , GOMI T. , HIGURASHI Y. , IEKI K. , IMAI N. , IWASA N. , IWASAKI H. , KANNO S. , KUBONO S. , KUNIBU M. , MICHIMASA S. , MOTOBAYASHI T. , NAKAMURA T. , RYUTO H. , SAKURAI H. , SERATA M. , TAKESHITA E. , TAKEUCHI S. , TERANISHI T. , UE K. , YAMADA K. , YANAGISAWA Y.
Published: July 2010

Cluster structures in the neutron-rich nucleus 12 Be were experimentally investigated via α-inelastic scattering. Excited states in the 12 Be nucleus were populated by a 12 Be (αα') reaction at 60 A MeV in the inverse kinematics, and identified by measuring a 6 He +6 He and α+8 He breakup channels in coincidence. The differential cross section and the angular correlations between the decay particles were obtained for each excitation energy at 10–20 MeV for 6 He +6 He and at 9–19 MeV for α+8 He , respectively, reconstructed by the measured momentum vectors of the two helium isotopes. A multipole decomposition analysis based on the distorted-wave Born approximation was applied for the angular distribution of the inelastic scattering together with the angular correlation between the decay particles with respect to the directions of the incident beam and to the momentum transfer simultaneously. From the decomposed excitation energy spectra for J=0-4, several new excited states were identified. The 0+ excited states were candidates of the band-head of a largely deformed rotational band. The 11.3-MeV 0+ state was found to decay only into the 6 He +6 He channel. This result support the recent theoretical result by the generalized two-center cluster model. Several negative-parity excited states were observed in the α+8 He channel. These excited states possibly forming a negative-parity rotational band, which is very closed to the positive-parity band, can be connected to the existence of the extremely developed cluster structure in 12 Be .
LINEAR-CHAIN STRUCTURE OF THREE-α-CLUSTERS IN 12C, 16C, AND 20C
Authors: MARUHN J. A. , LOEBL N. , UMAR A. S. , ITAGAKI NAOYUKI , KIMURA M. , HORIUCHI H. , TOHSAKI A.
Published: July 2010

We present Skyrme-force Hartree–Fock calculations of metastable three-α chain-state configurations in 12 C , 16 C , and 20 C . A microscopic dynamical study of reactions involving three 4 He clusters shows that the triple-α linear chain configuration of 12 C is formed with a certain lifetime and subsequently decays into a triangular configuration of 12 C and then to a configuration near the ground state.
ONE- AND TWO-NUCLEON STRUCTURE FROM GREEN'S FUNCTION THEORY
Authors: BARBIERI C. , HJORTH-JENSEN M. , GIUSTI C. , PACATI F. D.
Published: July 2010

We review some applications of self-consistent Green's function theory to studies of one- and two-nucleon structure in finite nuclei. Large-scale microscopic calculations that employ realistic nuclear forces are now possible. Effects of long-range correlations are seen to play a dominant role in determining the quenching of absolute spectroscopic factors. They also enhance considerably (e,e' pn ) cross sections in superparallel kinematics, in agreement with observations.
THREE α STATE AROUND 40Ca
Authors: ITAGAKI N. , KOKALOVA TZ. , VON OERTZEN W.
Published: July 2010

We have studied three α states around 40 Ca based on a microscopic α-cluster model, which has been succeeded experimentally quite recently. This was performed by introducing a Monte Carlo technique for the description of the THSR (Tohsaki Horiuchi Schuck Röpke) wave function, which is called the "virtual THSR" wave function. The three α cluster state around 40 Ca has an energy below the Coulomb barrier top energy with a spatial extension comparable to the second 0+ state of 12 C .
ISOSPIN SYMMETRY OF Tz = ±3/2 → ±1/2 GAMOW-TELLER TRANSITIONS IN A = 37 AND A = 41 NUCLEI
Authors: SHIMBARA Y. , FUJITA Y. , ADACHI T. , BERG G. P. A. , BROWN B. A. , FUJIMURA H. , FUJITA H. , FUJITA K. , HARA K. , HARA K. Y. , HATANAKA K. , KAMIYA J. , KATORI K. , KAWABATA T. , NAKANISHI K. , SAKAMOTO N. , SAKEMI Y. , SHIMIZU Y. , TAMESHIGE T. , UCHIDA M. , WAKASA T. , YOSHIFUKU M. , YOSOI M. , ZEGERS R. G. T.
Published: July 2010

Under the assumption of good isospin symmetry, Tz = ±3/2 → ±1/2 Gamow-Teller (GT) transitions in a mass A isobar are analogous, where Tz is the z component of isospin T defined by 1/2(N - Z). We studied the Tz = +3/2 → +1/2 GT transitions by using the 37 Cl (3 He ,t)37 Ar and 41 K (3 He ,t)41 Ca reactions at E beam = 140 MeV / nucleon . The GT transition strengths in 37 Ar and 41 Ca were obtained up to the excitation energy (Ex) of 14.2 MeV and 10.4 MeV with energy resolutions of 30 and 35 keV, respectively. The obtained GT strengths were compared with those of the Tz = -2/3 → -1/2 mirror transitions, measured by the β-decay of 37 Ca and 41 Ti , respectively. It was found that the overall distributions of the mirror transitions were similar in both A = 37 and A = 41 systems. In A = 37 the differences seen at lower excitation energies are suggested to be the effect of the tensor interaction in the charge-exchange reaction. The differences seen at higher excitation energies are suggested to be the effect of the Coulomb interaction that can break the mirror symmetry of the strength distributions.
NEXT-GENERATION AB INITIO SHELL MODEL FOR EXOTIC NUCLEAR STRUCTURES
Authors: DRAAYER J. P. , DYTRYCH T. , SVIRATCHEVA K. D.
Published: July 2010

A symmetry-adapted open-core shell model with SU (3) the underpinning symmetry is described. The model reduces to the well established Elliott SU (3) model in its 0ħΩ limit and to the no-core shell model (NCSM) – successful in describing low-energy dynamics of light nuclei – if stripped of its special symmetry considerations. We show that this approach is effective in providing an efficient description of low-lying eigenstates of 12 C and 16 O . A symmetry-guided framework is suggested based on our recent findings of low-spin and high-deformation dominance in realistic NCSM results. This holds promise to significantly enhance the reach of ab initio shell models toward heavier nuclear systems as well as descriptions of collective and cluster phenomena.
CLOSING REMARKS
Authors: LOVAS R. G.
Published: July 2010

In this closing address I attempt to summarize the Symposium by systematizing the topics covered, and I express our appreciation to all whom it is due to.
PAIRING VIBRATIONS STUDY USING A TIME-DEPENDENT ENERGY-DENSITY-FUNCTIONAL APPROACH
Authors: AVEZ B. , CHOMAZ Ph. , DUGUET T. , SIMENEL C.
Published: July 2010

We discuss pairing vibrations in the context of Time-Dependent Energy-Density-Functional formalism. The focus is put on the pairing part of the energy functional. We found that the density-dependence of the pairing functional impacts 2-nucleons transfer strengths.
THE FINITE AMPLITUDE METHOD FOR THE QRPA
Authors: AVOGADRO PAOLO , NAKATSUKASA TAKASHI
Published: July 2010

We present the finite amplitude method (FAM) for the Quasi Particle Random Phase Approximation (QRPA). This method allows to extract a QRPA code starting from a Hartree-Fock-Bogoliubov (HFB) code. The code obtained is fully self consistent, moreover since the FAM is not restricted to spherical symmetry it can be used to obtain deformed QRPA codes.
FIVE-DIMENSIONAL TOY MODEL FOR PARTICLE CONFINEMENT IN SPATIALLY-WARPED EINSTEIN UNIVERSE
Authors: DARIESCU MARINA-AURA , DARIESCU CIPRIAN
Published: July 2010

This paper deals with the confinement mechanism of chiral fermions evolving in a five-dimensional spacetime, with S3 × R four-dimensional slices. To construct the proper Yukawa-type Lagrangian, we must solve the Gordon and Dirac-type equations in the bulk. An intriguing fact that emerges from our analysis is that only the left-handed fermions can be trapped on the brane. Characterizing the wave functions by the quantum number mℓ, it turns out that for mℓ = 3/2 and mℓ ∈ {0, ±1}, once the coupling constant increases, the left-handed modes become more and more dominant in the brane, away from the {z = 0}-singularity.
A REMARK ON THE HIGH TEMPERATURE LIMIT OF QCD
Authors: GRANDOU T.
Published: July 2010

It is shown that in the high temperature limit, the QED and QCD effective actions differ only in the su(3)-Lie algebra valuation of the gauge fields.
COMMENTS ON SUSY INFLATION MODELS ON THE BRANE
Authors: LEE LU-YUN , CHEUNG KINGMAN , LIN CHIA-MIN
Published: July 2010

In this paper we consider a class of inflation models on the brane where the dominant part of the inflaton scalar potential does not depend on the inflaton field value during inflation. In particular, we consider supernatural inflation, its hilltop version, A-term inflation, and supersymmetric (SUSY) D- and F-term hybrid inflation on the brane. We show that the parameter space can be broadened, the inflation scale generally can be lowered, and still possible to have the spectral index ns = 0.96.