bluuebunny/crossref_metadata_2025 huggingface dataset:
Polarized emission from GaN/AlN quantum dots subject to uniaxial thermal interfacial stresses
Authors: Moshe O. , Rich D. H. , Damilano B. , Massies J.
Published: July 2010

The authors have studied the excitation-dependent optical properties of GaN/AlN self-assembled quantum dots (QDs) grown on Si(111) substrates. Ensembles of QDs were subject to various external stress configurations that resulted from the thermal expansion coefficient mismatch between the GaN/AlN layers and the Si(111) substrate and ranged from in-plane uniaxial stress, primarily along the ⟨11-20⟩ directions, to in-plane biaxial stress, having magnitudes ranging from 15 to 30 kbars. The authors have exploited microcracks that form during the postgrowth cooling as stressors in order to create the highly localized regions of uniaxial stress over limited regions of the samples. Cathodoluminescence (CL) measurements of the excitonic transitions exhibit an in-plane linear polarization anisotropy in close proximity to microcracks that is strongly dependent on the e-beam current used to excite the QD ensemble. The excitonic transition energy in varying proximity to the microcracks was studied with CL wavelength imaging. Some aspects of the carrier recombination are inferred from the temperature dependence of the integrated CL intensity. CL activation energy (AE) imaging is used to study changes in the AE for the thermal quenching of the luminescence in close proximity to the microcracks, and correlations are obtained with changes in the QD excitonic transition energy and changes in the average AlN band edge energies relative to the ground electron and hole states in the QD. Localized CL spectroscopy of the QDs exhibits emissions from both the ground and excited states, whose relative contributions depend on the level of excitation and temperature. Experimental results indicate that the polarization anisotropy vanishes at high temperatures (∼300 K) with an increasing excitation of the QDs, while the anisotropy decreases more slowly with excitation at low temperatures (∼60 K). A theoretical modeling of the effect of carrier filling on the polarization anisotropy and the excitonic transition energy was performed, as based on three-dimensional self-consistent solutions of the Schrödinger and Poisson equations using the 6×6 k⋅p and effective mass methods for the calculation of the e-h wave functions. The authors attribute carrier filling and a thermal excitation of holes into higher energy QD hole states during excitation to account for the observed gradual decrease in the polarization anisotropy with an increasing electron-hole pair excitation density at T=300 K.
Dynamics of temporal variations in phonatory flow
Authors: Krane Michael H. , Barry Michael , Wei Timothy
Published: July 2010

This paper addresses the dynamic relevance of time variations of phonatory airflow, commonly neglected under the quasisteady phonatory flow assumption. In contrast to previous efforts, which relied on direct measurement of glottal impedance, this work uses spatially and temporally resolved measurements of the velocity field to estimate the unsteady and convective acceleration terms in the unsteady Bernoulli equation. Theoretical considerations suggest that phonatory flow is inherently unsteady when two related conditions apply: (1) that the unsteady and convective accelerations are commensurate, and (2) that the inertia of the glottal jet is non-negligible. Acceleration waveforms, computed from experimental data, show that unsteady and convective accelerations to be the same order of magnitude, throughout the cycle, and that the jet flow contributes significantly to the unsteady acceleration. In the middle of the cycle, however, jet inertia is negligible because the convective and unsteady accelerations nearly offset one another in the jet region. These results, consistent with previous findings treating quasisteady phonatory flow, emphasize that unsteady acceleration cannot be neglected during the final stages of the phonation cycle, during which voice sound power and spectral content are largely determined. Furthermore, glottal jet dynamics must be included in any model of phonatory airflow.
Time domain wave separation using multiple microphones
Authors: Kemp Jonathan A. , van Walstijn Maarten , Campbell D. Murray , Chick John P. , Smith Richard A.
Published: July 2010

Methods of measuring the acoustic behavior of tubular systems can be broadly characterized as steady state measurements, where the measured signals are analyzed in terms of infinite duration sinusoids, and reflectometry measurements which exploit causality to separate the forward and backward going waves in a duct. This paper sets out a multiple microphone reflectometry technique which performs wave separation by using time domain convolution to track the forward and backward going waves in a cylindrical source tube. The current work uses two calibration runs (one for forward going waves and one for backward going waves) to measure the time domain transfer functions for each pair of microphones. These time domain transfer functions encode the time delay, frequency dependent losses and microphone gain ratios for travel between microphones. This approach is applied to the measurement of wave separation, bore profile and input impedance. The work differs from existing frequency domain methods in that it combines the information of multiple microphones within a time domain algorithm, and differs from existing time domain methods in its inclusion of the effect of losses and gain ratios in intermicrophone transfer functions.
Suppression and comodulation masking release in normal-hearing and hearing-impaired listeners
Authors: Ernst Stephan M. A. , Rennies Jan , Kollmeier Birger , Verhey Jesko L.
Published: July 2010

The detectability of a sinusoidal signal embedded in a masker at the signal frequency can be improved by simultaneously presenting additional maskers in off-frequency regions if the additional maskers and the on-frequency masker component have the same temporal envelope. This effect is commonly referred to as comodulation masking release (CMR). Recently, it was hypothesized that peripheral nonlinear processes such as suppression may play a role in CMR over several octaves when the level of the off-frequency masker component is higher than the level of the on-frequency masker component. The aim of the present study was to test this hypothesis by measuring suppression and CMR within the same subjects for various frequency-level combinations of the off-frequency masker component. Experimental data for normal-hearing listeners show a large overlap between the existence regions for suppression and CMR. Hearing-impaired subjects with a sensorineural hearing loss show, on average, negligible suppression and CMR. The data support the hypothesis that part of the CMR in experiments with large spectral distances and large level differences between the masker components is due to the nonlinear processing at the level of the cochlea.
An investigation of floor impact sources and perception models of impact sounds
Authors: Lee Pyoung Jik
Published: July 2010

The present work compared the physical and psychoacoustical characteristics of standard impact sources with those of human impacts, and proposed the perception models of annoyance for impact sounds with respect to temporal and spatial aspects. Impact ball (heavy/soft impact source) was selected as an appropriate standard floor impact source simulating real floor impacts based on the objective evaluation and similarity judgment. Then, measurements using impact ball were conducted in a variety of apartment buildings with different floor structure and coverings. Variations in frequency characteristics were found in the measurement results, thus these were classified into three groups, Groups A-C. Differences between Groups A-C were clarified using sound quality metrics. Finally, perception models of impact ball sounds were developed in relation to temporal aspects and spatial characteristics, respectively. When the spatial characteristics kept constant, perceptions of annoyance for impact ball sounds were affected mainly by the differences in fluctuation strength as well as loudness. Another perception model comprised of IACC (Interaural cross-correlation function) was also proposed through auditory experiments. It was found that IACC had an effect on the perception of impact ball sounds with sound pressure level, and the contribution of IACC on perception of impact ball sounds was around 20%
Theoretical investigation of shear stress generated by a contrast microbubble on the cell membrane as a mechanism for sonoporation
Authors: Doinikov Alexander A. , Bouakaz Ayache
Published: July 2010

There are numerous experimental investigations on sonoporation, while the theoretical background of this phenomenon still is in its infancy. One of the suggested mechanisms of sonoporation is linked to shear stress exerted on the cell membrane by acoustic microstreaming generated by a contrast microbubble pulsating nearby a cell. Currently, the existing model of this effect is based on an equation that has been derived for a free hemispherical bubble resting on a rigid plane. Such a model is not adequate for a contrast microbubble. In this paper, an improved theory is suggested that assumes an encapsulated bubble to be detached from the cell membrane. The improved model allows one to calculate the shear stress distribution on the cell membrane at different values of the acoustic parameters. The second problem considered is how to apply the model for pairwise bubble-cell interactions to bubble-cell solutions, which one has to deal with in experiments. An approach is proposed to evaluate the number of sonoporated cells in a bubble-cell solution. It is shown that the reaction of a bubble-cell solution to the variation of the acoustic parameters can be different from what is predicted by the analysis of interactions between single bubbles and cells.
Acoustic localization of antbirds in a Mexican rainforest using a wireless sensor network
Authors: Collier Travis C. , Kirschel Alexander N. G. , Taylor Charles E.
Published: July 2010

Acoustic localization is a promising method to passively observe vocal animal species, but remains difficult and time consuming to employ. To reduce the labor intensity and impact of deployment, an acoustic localization system has been developed consisting of battery powered wireless sensor nodes. The system also has the ability to perform an acoustic self-survey, which compares favorably in accuracy to global positioning system survey methods, especially in environments such as forest. The self-survey and localization accuracy of the system was tested in the neotropical rainforest of Chiapas, Mexico. A straight-forward and robust correlation sum localization computation method was utilized and is described in detail. Both free-ranging wild antbird songs and songs played from a speaker were localized with mean errors of 0.199 m and 0.445 m, respectively. Finally, additional tests utilizing only a short segment of each song or a subset of sensor nodes were performed and found to minimally affect localization accuracy. The use of a wireless sensor network for acoustic localization of animal vocalizations offers greater ease and flexibility of deployment than wired microphone arrays without sacrificing accuracy.
Does training on a phonemic contrast absent in the listener’s dialect influence word recognition?
Authors: Dufour Sophie , Nguyen Noël , Frauenfelder Ulrich Hans
Published: July 2010

Southern French listeners were trained on the word final Standard French /e/-/ɛ/ contrast that does not exist in their dialect. They learned to associate minimal pairs of new words with visual shapes. Although final training session performance was relatively high, the learning did not transfer to a lexical decision task with phonological priming. Thus successful training on a phonemic contrast did not guarantee the efficient use of this contrast in spoken word recognition tasks. These findings are discussed in light of abstractionist and exemplarist models.
Binaural interference in lateralization thresholds for interaural time and level differences
Authors: Heller Laurie M. , Richards Virginia M.
Published: July 2010

Listeners discriminated changes in either interaural time differences (ITDs) or interaural level differences (ILDs) in one noise band (the target) in the presence or absence of an uninformative spectrally-remote second noise band (the interferer). The noise bands had center frequencies of 500 and 4000 Hz and bandwidths of 50 and 400 Hz, respectively. When one band was a target, the other served as an interferer. The interferer was presented either diotically or dichotically with ITDs or ILDs that varied randomly across intervals. “Interference” was defined as occurring if the target thresholds were elevated in the presence of an interferer. For ITD discrimination, interference was greater for the 4000-Hz target than for the 500-Hz target, but for ILD discrimination, interference for the 500-Hz target was greater than or equal to that obtained for the 4000-Hz target. Larger interference effects were obtained when the interferer ITD or ILD was randomly varied, revealing that interference can be large not only for high-frequency targets but also for low-frequency targets with high-frequency interferers. The data are consistent with a model in which listeners combine lateral position across frequency with interaural information weighted according to the accuracy with which positions are encoded in each frequency region.
Phonetic enhancement of sibilants in infant-directed speech
Authors: Cristià Alejandrina
Published: July 2010

The hypothesis that vocalic categories are enhanced in infant-directed speech (IDS) has received a great deal of attention and support. In contrast, work focusing on the acoustic implementation of consonantal categories has been scarce, and positive, negative, and null results have been reported. However, interpreting this mixed evidence is complicated by the facts that the definition of phonetic enhancement varies across articles, that small and heterogeneous groups have been studied across experiments, and further that the categories chosen are likely affected by other characteristics of IDS. Here, an analysis of the English sibilants /s/ and /ʃ/ in a large corpus of caregivers’ speech to another adult and to their infant suggests that consonantal categories are indeed enhanced, even after controlling for typical IDS prosodic characteristics.
Effect of spatial separation, extended bandwidth, and compression speed on intelligibility in a competing-speech task
Authors: Moore Brian C. J. , Füllgrabe Christian , Stone Michael A.
Published: July 2010

The benefit for speech intelligibility of extending the bandwidth of hearing aids was assessed when the target speech (sentences) and background (two talkers) were co-located or spatially separated. Also, the relative benefits of slow and fast compression were assessed. Sixteen hearing-impaired (HI) subjects with mild-to-moderate high-frequency hearing loss and eight normal-hearing (NH) subjects were tested. The target and interfering sounds were recorded using a KEMAR manikin and were located at ±60° azimuth, either co-located or spatially separated. Simulated binaural hearing-aid processing using five-channel slow or fast compression was performed offline, with gains set individually for each HI subject. Upper cutoff frequencies were 5, 7.5, or 10 kHz. Processed stimuli were presented via headphones. For both NH (unaided) and HI subjects, there was no significant effect of cutoff frequency for the co-located condition, but a small but significant benefit from increasing the cutoff frequency from 5 to 7.5 kHz for the spatially separated condition. For the HI subjects, slow compression gave slightly but significantly higher scores than fast compression for the spatially separated but not for the co-located condition. There were marked individual differences both in the benefit from extended bandwidth and in the relative benefit of slow and fast compression.
Temporal weighting of interaural time and level differences in high-rate click trains
Authors: Brown Andrew D. , Stecker G. Christopher
Published: July 2010

Temporal weighting functions (TWFs), quantifying sensitivity to interaural time differences (ITD) and interaural level differences (ILD) over the duration of brief stimuli, were measured in 6 normal hearing subjects using trains of 16 Gabor clicks centered at 4 kHz presented dichotically at 4 rates [inter-click intervals (ICI) of 10, 5, 2.5, and 1.25 ms]. Random ITD or ILD were imposed independently on each click in the train in separate conditions. The subject’s task was to discriminate the lateral position of the click train (“left” or “right”). Receiver operating characteristic (ROC) analysis was then used to quantify the effectiveness or “weight” of each click according to individual click ITD or ILD. Although individual differences were evident, onset cues appeared to dominate at high rates. Onset dominance was apparent for both ITD and ILD at 1.25 ms ICI and for ITD at 2.5 ms ICI, but for neither cue at 5 or 10 ms ICI. Onset dominance was greater on average for ITD than ILD, although TWFs were qualitatively similar for the two cues. No evidence was found for “upweighting” of late-arriving ILD [Stecker, G. C., and Hafter, E. R. (2009), J. Acoust. Soc. Am. 125, 3914–3924].
A sound budget for the southeastern Bering Sea: Measuring wind, rainfall, shipping, and other sources of underwater sound
Authors: Nystuen Jeffrey A. , Moore Sue E. , Stabeno Phyllis J.
Published: July 2010

Ambient sound in the ocean contains quantifiable information about the marine environment. A passive aquatic listener (PAL) was deployed at a long-term mooring site in the southeastern Bering Sea from 27 April through 28 September 2004. This was a chain mooring with lots of clanking. However, the sampling strategy of the PAL filtered through this noise and allowed the background sound field to be quantified for natural signals. Distinctive signals include the sound from wind, drizzle and rain. These sources dominate the sound budget and their intensity can be used to quantify wind speed and rainfall rate. The wind speed measurement has an accuracy of ±0.4 m s−1 when compared to a buoy-mounted anemometer. The rainfall rate measurement is consistent with a land-based measurement in the Aleutian chain at Cold Bay, AK (170 km south of the mooring location). Other identifiable sounds include ships and short transient tones. The PAL was designed to reject transients in the range important for quantification of wind speed and rainfall, but serendipitously recorded peaks in the sound spectrum between 200 Hz and 3 kHz. Some of these tones are consistent with whale calls, but most are apparently associated with mooring self-noise.
Lateralization of noise-burst trains based on onset and ongoing interaural delays
Authors: Freyman Richard L. , Balakrishnan Uma , Zurek Patrick M.
Published: July 2010

The lateralization of 250-ms trains of brief noise bursts was measured using an acoustic pointing technique. Stimuli were designed to assess the contribution of the interaural time delay (ITD) of the onset binaural burst relative to that of the ITDs in the ongoing part of the train. Lateralization was measured by listeners’ adjustments of the ITD of a pointer stimulus, a 50-ms burst of noise, to match the lateral position of the target train. Results confirmed previous reports of lateralization dominance by the onset burst under conditions in which the train is composed of frozen tokens and the ongoing part contains multiple ambiguous interaural delays. In contrast, lateralization of ongoing trains in which fresh noise tokens were used for each set of two alternating (left-leading/right-leading) binaural pairs followed the ITD of the first pair in each set, regardless of the ITD of the onset burst of the entire stimulus and even when the onset burst was removed by gradual gating. This clear lateralization of a long-duration stimulus with ambiguous interaural delay cues suggests precedence mechanisms that involve not only the interaural cues at the beginning of a sound, but also the pattern of cues within an ongoing sound.
Prior listening in rooms improves speech intelligibility
Authors: Brandewie Eugene , Zahorik Pavel
Published: July 2010

Although results from previous studies have demonstrated that the acoustic effects of a single reflection are perceptually suppressed after repeated exposure to a particular configuration of source and reflection, the extent to which this dynamic echo suppression might generalize to speech understanding in room environments with multiple reflections and reverberation is largely unknown. Here speech intelligibility was measured using the coordinate response measure corpus both with and without prior listening exposure to a reverberant room environment, which was simulated using virtual auditory space techniques. Prior room listening exposure was manipulated by presenting either a two-sentence carrier phrase that preceded the target speech, or no carrier phrase within the room environment. Results from 14 listeners indicate that with prior room exposure, masked speech reception thresholds were on average 2.7 dB lower than thresholds without exposure, an improvement in intelligibility of over 18 percentage points on average. This effect, which is shown to be absent in anechoic space and greatly reduced under monaural listening conditions, demonstrates that prior binaural exposure to reverberant rooms can improve speech intelligibility, perhaps due to a process of perceptual adaptation to the acoustics of the listening room.
Maximization of acoustic energy difference between two spaces
Authors: Shin Mincheol , Lee Sung Q. , Fazi Filippo M. , Nelson Philip A. , Kim Daesung , Wang Semyung , Park Kang Ho , Seo Jeongil
Published: July 2010

There has recently been an increasing interest in the generation of a sound field that is audible in one spatial region and inaudible in an adjacent region. The method proposed here ensures the control of the amplitude and phase of multiple acoustic sources in order to maximize the acoustic energy difference between two adjacent regions while also ensuring that evenly distributed source strengths are used. The performance of the method proposed is evaluated by computer simulations and experiments with real loudspeaker arrays in the shape of a circle and a sphere. The proposed method gives an improvement in the efficiency of radiation into the space in which the sound should be audible, while maintaining the acoustic pressure difference between two acoustic spaces. This is shown to give an improvement of performance compared to the contrast control method previously proposed.
Egg white as a blood coagulation surrogate
Authors: Liu Yunbo , Maruvada Subha , Herman Bruce A. , Harris Gerald R.
Published: July 2010

Egg white, a protein-containing solution, is characterized as a blood coagulation surrogate for the acoustical and thermal evaluation of therapeutic ultrasound, especially high intensity focused ultrasound (HIFU) devices. Physical properties, including coagulation temperature, frequency dependent attenuation, sound speed, viscosity, and thermal properties, were measured as a function of temperature (20–95 °C). Thermal coagulation and attenuation (5–12 and 1 MHz) of cow blood, pig blood, and human blood also were assessed and compared with egg white. For a 30 s thermal exposure, both egg white and blood samples (3 mm thickness) started to denature at 65 °C and coagulate into an elastic gel at 85 °C. The attenuation of egg white was found to be similar to that of the blood samples, having values of 0.23f1.09, 1.58f0.61, and 2.7f0.5 dB/cm at 20, 75, and 95 °C, respectively. This significant attenuation increase with temperature was determined to be caused mainly by bubble cavity formation. The other temperature-dependent parameters are also similar to the reported values for blood. These properties make egg white a potentially useful bench testing tool for the safety and efficacy evaluation of therapeutic ultrasound devices.
A proposed neural mechanism underlying auditory continuity illusions
Authors: Vinnik Ekaterina , Itskov Pavel , Balaban Evan
Published: July 2010

A numerical thought experiment was conducted to assess whether stimulus-specific, short-term changes in auditory neural responsiveness could explain the formation of auditory objects underlying the auditory continuity illusion. A tonotopic, two-layer feedforward network model with one time constant for synaptic weight augmentation based on firing rate, and an independent time constant for synaptic weight decay was presented with classical continuity illusion stimuli. The results suggest that the continuity illusion could, in principle, be explained by basic, duration-dependent auditory circuit behavior, which could emerge at either early or later stages of processing.
Global boundary flattening transforms for acoustic propagation under rough sea surfaces
Authors: Oba Roger M.
Published: July 2010

This paper introduces a conformal transform of an acoustic domain under a one-dimensional, rough sea surface onto a domain with a flat top. This non-perturbative transform can include many hundreds of wavelengths of the surface variation. The resulting two-dimensional, flat-topped domain allows direct application of any existing, acoustic propagation model of the Helmholtz or wave equation using transformed sound speeds. Such a transform-model combination applies where the surface particle velocity is much slower than sound speed, such that the boundary motion can be neglected. Once the acoustic field is computed, the bijective (one-to-one and onto) mapping permits the field interpolation in terms of the original coordinates. The Bergström method for inverse Riemann maps determines the transform by iterated solution of an integral equation for a surface matching term. Rough sea surface forward scatter test cases provide verification of the method using a particular parabolic equation model of the Helmholtz equation.
Frequency synchronization of blue whale calls near Pioneer Seamount
Authors: Hoffman Michael D. , Garfield Newell , Bland Roger W.
Published: July 2010

Vocalizations of blue whales were recorded with a cabled hydrophone array at Pioneer Seamount, 50 miles off the California coast. Most calls occurred in repeated sequences of two-call pairs (A, then B). The B call is a frequency-modulated tone highly repeatable in form and pitch. A model of this sound is described which permits detecting very small frequency shifts. B calls are found to be aligned in frequency to about one part in 180. This requires very fine pitch discrimination and control over calling frequency, and suggests that synchronizing to a common frequency pattern carries some adaptive advantage. Some possibilities for acoustic sensing by whales requiring this fine frequency resolution are discussed.
Shadowing reduced speech and alignment
Authors: Brouwer Susanne , Mitterer Holger , Huettig Falk
Published: July 2010

This study examined whether listeners align to reduced speech. Participants were asked to shadow sentences from a casual speech corpus containing canonical and reduced targets. Participants’ productions showed alignment: durations of canonical targets were longer than durations of reduced targets; and participants often imitated the segment types (canonical versus reduced) in both targets. The effect sizes were similar to previous work on alignment. In addition, shadowed productions were overall longer in duration than the original stimuli and this effect was larger for reduced than canonical targets. A possible explanation for this finding is that listeners reconstruct canonical forms from reduced forms.
Differences in distortion product otoacoustic emission phase recorded from human neonates using two popular probes
Authors: Abdala Carolina , Dhar Sumitrajit
Published: July 2010

DPOAE (2f1-f2) phase was measured across a 3-octave frequency range from two groups of newborns using ER10B+ and ER10C probe microphones. A marked phase shift was noted in the mid-to-high frequency range for newborn data recorded with the ER10C only. In contrast, the ER10B+ produced phase that was approximately invariant as a function of frequency for most of the range. Probe-related phase shifts can be effectively eliminated by correcting for variations in the phases of the primary tones. Results highlight the importance of detecting and correcting for system-related phase shifts so they are not misinterpreted as cochlear in origin.
A relationship between the waveguide invariant and wavenumber integration
Authors: Cockrell Kevin L. , Schmidt Henrik
Published: July 2010

The waveguide invariant is typically defined using of normal modes or ray theory, but it can also be related to the wavenumber-integration method for calculating the acoustic field in a waveguide. In this letter, the Wiener–Khinchin Theorem is used to show that the autocorrelation of the wavenumber-integration kernel, when plotted versus wavenumber difference and frequency, contains striations that can be described by the waveguide invariant.
Structure Cylindrique Verticale dans un Dépôt Meuble Quaternaire, au Nord de Montréal, Québec
Authors: Dionne Jean-Claude , Laverdière Camille
Published: July 2010

A vertical cylindrical structure, with concentric layers, occurs in a thick sand and silt Quaternary deposit north of Montreal. The cylinder transects horizontally-layered fine, medium, and coarse stratified sand; beds are 2–4 cm or 8–10 cm in thickness, and many are characterized by cross stratification. The cylinder has a total height (observed) of 152.5 cm and a diameter of 34 cm at the top and 24 cm at the base. A horizontal section at the top shows internal structure characterized by concentric layers of medium sand, fine sand, and silt in the center; the vertical section exhibits cone-in-cone structure. Micro-faults occur in proximal surrounding layers and within the structure itself. It is suggested that this vertical, cylindrical structure resulted from the action of a whirlpool eroding a deep cylindrical hole in unconsolidated sediments. Refilling of the hole by particles previously sucked off by the whirlpool immediately followed the erosional phase. The concentric arrangement of layers results from the settling of particles under whirlpool motion. Another possible origin of the structure is a spring rising through unconsolidated sands.
The engineering significance of Pleistocene stratigraphy in the Saskatoon area, Saskatchewan, Canada
Authors: MacDonald A. B. , Sauer E. Karl
Published: July 2010

It was recognized that repeated stages and substages of glaciation in Saskatchewan during the Pleistocene Epoch produced a series of overlapping sediments. It was shown that these sediments could be analyzed for engineering purposes within a three-dimensional stratigraphic framework. Preliminary field investigations indicated that a stratigraphic analysis could be related to construction problems found on highway embankment construction, gravel location, and tunnel excavation. Field studies established that it is practical for the field engineer to analyze and interpret the stratigraphy in the field. Furthermore, laboratory studies indicated that there were significant differences in the engineering properties of different drift-stratigraphic units. It was shown that the behavior of the till units during construction could be explained in terms of the fundamental engineering properties of soils such as shear strength parameters and compressibility. Finally, it appeared to be probable that the basic concepts developed in this study would apply to other areas covered by glacial sediments.
Riverbank stability study at the University of Alberta, Edmonton
Authors: Thomson S.
Published: July 2010

The need for new building sites at the University of Alberta required an investigation of the stability of the valley wall of the North Saskatchewan River within the limits of the campus.A geologic map and stratigraphic sections were drawn which show Upper Cretaceous shales and sandstones overlain by preglacial sands and gravels which, in turn, are overlain by till and glacial lake sediments.A large, buried preglacial valley on the western side of the study area enhances slope stability because it lowers the piezometric surface. Landslide analyses in this area indicate that effective strength parameters near peak values are being mobilized.On the eastern side of the study area old landslides are revealed by subdued slump topography. Residual strength parameters used in an infinite slope analysis result in low factors of safety.
Effect of groundwater levels on stress history of the St. Clair clay till deposit
Authors: Soderman L. G. , Kim Y. D.
Published: July 2010

Over 100 ft (30.4 m) of relatively homogeneous and compressible lacustrine clay and clay till deposits cover a large portion of the St. Clair basin in Southwestern Ontario. The deposit is commonly considered to be normally consolidated at depth with an overconsolidated crust caused by desiccation and weathering.Based on data from recent laboratory one-dimensional consolidation tests and evidence of a lowered groundwater level in the past, it can be shown that the St. Clair clay till deposits are, in general, lightly overconsolidated at depth, with a heavily overconsolidated crust in the upper 40 ft (12.2 m) of the deposit.The evidence of a higher degree of overconsolidation can be used to explain the large discrepancies between predicted and observed settlements of structures founded on the St. Clair clay till.
Hydrogeologic aspects of dewatering at Welland
Authors: Farvolden R. N. , Nunan J. P.
Published: July 2010

Realignment of the Welland Canal between Port Robinson and Port Colborne and the building of underpass structures necessitated both temporary and permanent depressurizing of an artesian aquifer. The aquifer is a thin zone of fractured dolomite found immediately beneath approximately 60 to 100 ft (18 to 30 m) of poorly-permeable glacial till and lacustrine sediments. Since most of the private wells in the Welland area obtain water from the bedrock aquifer, extensive well interference problems were anticipated. Problems in connection with the dewatering and depressurizing included design of deep-well pumping systems for excavation work, prediction and monitoring of drawdown effects, and the determination of responsibility for interference in specific areas since several dewatering systems with overlapping cones-of-depression would be operating simultaneously. To overcome a problem of insufficient hydrologic data prior to the commencement of dewatering, a contour map of the original piezometric surface was constructed from drillers' records. This map showed a normal groundwater flow system where the movement of groundwater was from local upland recharge areas to local discharge areas along the Welland River and the existing canal. A contour map of the drawdown was drawn on the assumption that deviations from the reconstructed original piezometric surface were caused by dewatering. Analysis of the cone-of-depression along with analyses of pre-engineering pumping tests provided values for aquifer coefficients required for solution of the unsteady flow equations. Because the coefficients used were average values for a relatively small area extrapolated over a broad area, the predicted drawdown showed considerable variation in reliability. The work did provide, however, a check on the numerical method (Frind 1970) which takes into account local variations.
Experiences with alluvial foundations for earth dams in the Prairie provinces
Authors: Peters N. , Lamb K. N.
Published: July 2010

The foundations for numerous dams in proglacial and interglacial valleys in the Prairie provinces consist of soft alluvial soils. The deposits are up to 60 m deep, and contain thick layers of clay interspersed with lenses and layers of silt, sand, and gravel.This paper describes the damsite investigation and laboratory testing required, the design methods and construction procedures used, and the foundation performance observed during and after construction. A number of empirical relationships between index tests and physical properties of the soils, which provide useful guidelines for preliminary design, are presented.The design approach has gradually evolved from an empirical design with limited testing to a more rational design based on detailed investigations and thorough instrumentation. Increased reliance is placed on observational apparatus to monitor movements and pore pressures to confirm design assumptions as construction proceeds. The theoretical design is always checked with former designs of dams that have performed satisfactorily.Safe economical dams have been constructed in spite of large deformations and high pore pressures. Two case histories illustrate the wide range in dam design for alluvial foundations. The first shows an older design cross section with modifications required to ensure a stable dam, and the second describes a recently constructed dam that incorporates many of the latest design concepts.
Mineralogical and engineering index properties of the basal McMurray Formation clay shales
Authors: Dusseault Maurice B. , Scafe Don
Published: July 2010

Analysis of 83 specimens of the basal McMurray Formation clay shales (basal clays) has revealed a novel clay mineralogical suite: the clays are illite–kaolinite clays, but vermiculite and mixed-layer clays are present in significant amounts. Index and engineering behavior are affected: high compressibilities, low residual angles of shearing resistance, and low permeabilities are characteristic; index properties, however, are typical of illite–kaolinite clays.Comparison of outcrop and borehole data reveal significant differences between the sample sources.The location of the basal clays at the base of future open pits has implications for oil-sand development with respect to highwall stability and tailings disposal structures.
Hydraulic efficiency of the Manicouagan-3 cutoff
Authors: Dascal O.
Published: July 2010

The hydraulic efficiency of a double-wall cutoff built through 126 m (420 ft) of pervious alluvial deposit filling a V-shaped canyon and under a 107 m (350 ft) high earthfill dam is discussed. The cutoff walls are made up of cast-in-place concrete interlocking piles and panels and are intended primarily to minimize the danger of piping, by controlling the pore pressures in the downstream zone of the dam. The behaviour of the cutoff, monitored by a comprehensive instrumentation program, indicated after [Formula: see text] years a relatively high hydraulic efficiency (over 92%). During this period the cutoff has exhibited a very slight decrease in its efficiency (less than 1%), probably due to leaching of the grout at the rock-wall contact in the grout curtain, and probably also due to some removal of the bentonite from between the piles and panels. The analysis of the efficiency of each wall considered individually (using Casagrande's latest recommendation) indicates a lower efficiency for the upstream wall as compared to that of the downstream wall, probably because of the migration of bentonite particles downstream under the hydraulic gradient. The double-wall cutoff exhibits an efficiency about 18–30% higher than that for a similar single-wall cutoff.
Use of glacial till and outwash silty sand as construction material for dam cores at Long Spruce Generating Station
Authors: McKeown J. D. , Matheson D. S.
Published: July 2010

This paper documents experience gained during the construction of the earthworks at the Long Spruce Generating Station using impervious core materials of different geologic origins. Testfills of glacial till made to compare compaction equipment are described. The results are discussed and the performance of self-propelled sheepsfoot and pneumatic 50 ton (45 Mg) rollers is compared. Problems encountered in the use of the two types of material are discussed. Problems with glacial outwash silty sand stemmed primarily from the variability of the material in the borrow pits. The till proved to be more homogeneous but certain care in excavation and conditioning was required. Construction control and quality control testing procedures are reviewed. Both nuclear and conventional density tests were utilized and the results are compared.
Logan and landslides: 1842
Authors: Legget Robert F.
Published: July 2010

Sir William Logan, first Director of the Geological Survey of Canada, observed in 1842, recorded in his field notebook, but did not describe in print, retrogressive, rotational slips in a landslide in Leda clay on the South Nation River of eastern Ontario. This predated the publication by Alexandre Collin in 1846 of his similar observations in France.
EFFECT OF AN OFF-SHELL TRANSFORMATION OF THE QUARK-MODEL NN INTERACTION IN THE NEUTRON-DEUTERON SCATTERING OBSERVABLES
Authors: FUJIWARA Y. , FUKUKAWA K.
Published: July 2010

We solve the nd scattering in the Faddeev formalism, employing the NN sector of the quark-model baryon-baryon interaction fss2. The energy-dependence of the NN interaction, inherent to the (3q)-(3q) resonating-group formulation, is eliminated by the standard off-shell transformation utilizing the [Formula: see text] factor, where N is the normalization kernel for the (3q)-(3q) system. This procedure yields an extra nonlocality to the quark-model exchange kernel, which is very important to reproduce all the observables for the bound state and elastic scattering below En ≤ 65 MeV .
EXPERIMENTAL INVESTIGATION OF THE STELLAR REACTION 30S(p,γ)31Cl VIA COULOMB DISSOCIATION
Authors: TOGANO Y. , MOTOBAYASHI T. , AOI N. , BABA H. , BISHOP S. , DOORNENBAL P. , FURUKAWA T. , KANNO S. , KONDO Y. , KUROKAWA M. , MATSUO Y. , MURAKAMI H. , TAKEUCHI S. , YAMADA K. , YONEDA K. , CAI X. , FANG D. , MA Y. G. , TIAN W. , WANG H. , IEKI K. , KURITA K. , MATSUSHITA M. , OKADA K. , SHIODA R. , YAMADA Y. , IWASA N. , KUME N. , KAWABATA T. , OTA S. , SHIMOURA S. , KOBAYASHI N. , NAKAMURA T. , SATOU Y. , TANAKA K. N. , KUBOKI T. , WANG J.
Published: July 2010

The Coulomb dissociation of the proton-rich nuclei 31 Cl was studied experimentally using 31 Cl beams at 58 MeV/nucleon with a lead target. The relative energy between the reaction products, 30 S and proton, was obtained. The first excited state in 31 Cl was observed which is relevant to the resonant capture of stellar 30 S (p,γ)31 Cl reaction.
NUCLEAR EXCITATIONS AND WEAK INTERACTION RATES AT FINITE TEMPERATURE
Authors: PAAR N. , MARKETIN T. , VRETENAR D. , NIU Y. F. , COLÒ G. , KHAN E. , MENG J.
Published: July 2010

Self-consistent theory frameworks have been introduced for description of excitations in nuclei at finite temperature, based on energy density functionals formulated using i) relativistic mean field Lagrangian with density dependent meson-nucleon vertex functions, and ii) Skyrme-type functionals. Finite temperature random phase approximation (FTRPA) has been employed in description of multipole excitations and charge-exchange modes. It is shown that in the temperature range T = 1–2 MeV additional transition strength appears at low energies due to thermal unblocking of single-particle orbitals close to the Fermi level. Within the finite temperature Hartree-Fock+RPA based on Skyrme functionals, the electron capture cross sections have been studied for target nuclei at temperatures relevant in modeling the supernova evolution.
THE DESCRIPTION AND ROLE OF FLUCTUATIONS IN COLLECTIVE DEGREES OF FREEDOM IN MODELS OF NUCLEAR STRUCTURE BASED ON THE SELF-CONSISTENT MEAN FIELD
Authors: BENDER MICHAEL , HEENEN PAUL-HENRI
Published: July 2010

This contribution sketches recent efforts to explicitly include fluctuations in collective degrees of freedom into a universal energy density functional method for nuclear structure, their successes, and some remaining open questions.
MULTI-QUASIPARTICLE ISOMERS INVOLVING PROTON-PARTICLE AND NEUTRON-HOLE CONFIGURATIONS IN 131I AND 133I
Authors: WATANABE H. , OGAWA K. , LANE G. J. , DRACOULIS G. D. , BYRNE A. P. , NIEMINEN P. , KONDEV F. G. , CARPENTER M. P. , JANSSENS R. V. F. , LAURITSEN T. , SEWERYNIAK D. , ZHU S. , CHOWDHURY P.
Published: July 2010

The nuclei 131 I and 133 I have been populated in multi-nucleon transfer reactions between 136 Xe ions and various targets, and their structure investigated by time-correlated γ-ray coincidence spectroscopy and the measurement of γ-ray angular correlations. A 19/2- isomer at 1918 keV, with a half-life of 24(1) µs, has been identified in 131 I , as well as nanosecond isomers with Jπ = 23/2+ in both isotopes. A T1/2 = 25(3) ns isomer at 4308 keV in 131 I is suggested to have Jπ = (31/2-, 33/2-) and is primarily attributed to the coupling of an odd proton in the d5/2 or g7/2 orbit with the [Formula: see text] configuration in 130 Te , responsible for the 15- isomer in that nucleus. The observed level properties are compared with predictions of a shell-model calculation.
RESEARCH OF SUPERHEAVY ELEMENTS AT RIKEN
Authors: MORITA KOSUKE
Published: July 2010

At RIKEN Nishina Center, a series of experiments for studying the heaviest elements has been done by using a gas-filled recoil ion separator (GARIS). Isotopes of the 112th and the 113th elements, 277 Cn and 278113 by the 70 Zn induced one neutron emission reactions on the targets 208 Pb and 209 Bi , respectively. The former provided an independent confirmation of the production of an isotope, 277 Cn , of the 112th element reported firstly by the GSI (Helmholtzzentrum für Schwerionenforschung GmbH, Germany) research group. The latter was the first observation of the 113th element produced by the 'cold fusion' reaction. A gas-jet transport system coupled to GARIS was successfully operated for the chemistry study of the heaviest elements.
CLUSTER STATES IN 12C AND 14C
Authors: FREER M. , ASHWOOD N. I. , CURTIS N. , MALCOLM J. , MUNOZ-BRITTON T. , WHELDON C. , ZIMAN V. A. , CARTER J. , FUJITA H. , USMAN I. , BUTHELEZI Z. , FÖRTSCH S. V. , NEVELING R. , PEREZ S. M. , SMIT F. D. , FEARICK R. W. , PAPKA P. , SWARTZ J. A. , BROWN S. , CATFORD W. N. , WILSON G. , BARDAYAN D. , PAIN S. D. , CHIPPS K. , GRZYWACZ-JONES K. , SOIĆ N. , ACHOURI N. L.
Published: July 2010

The cluster structure of 12 C is explored and recent measurements of proton inelastic scattering, suggesting a 2+ state close to 9.6 MeV are presented. Resonant scattering studies of 10 Be + 4 He used to populate resonances in 14 C are briefly discussed.
MOLECULAR STATES AND MOLECULAR ORBITALS IN N ≠ Zsd-SHELL NUCLEI
Authors: KIMURA MASAAKI , FURUTACHI NAOYA
Published: July 2010

The α-clustering and molecular-orbitals of 22 Ne and 22 Mg are investigated based on antisymmetrized molecular dynamics. The observed candidates for the α cluster states are understood as the molecular-orbital states and α + 18 O di-nuclei states. The molecular-orbitals in neutron-rich F isotopes are predicted and the drastic reduction of their excitation energy toward the neutron-drip line is discussed.
DINEUTRON CORRELATIONS IN He ISOTOPES
Authors: KANADA-EN'YO YOSHIKO , FELDMEIER HANS , SUHARA TADAHIRO
Published: July 2010

Spatial correlations of spin-zero neutron pairs in 6 He and 8 He are investigated by analyzing two-neutron density of microscopic wave functions obtained by antisymmetrized molecular dynamics (AMD). Results suggest dineutron correlations at the surface of these neutron-rich He isotopes. The dineutron correlations are weaker in the ground state of 8 He than in 6 He but again pronounced in the excited [Formula: see text] of 8 He .
ENHANCED E1 DECAYS MEASURED IN 212Po POPULATED BY α TRANSFER: A NOVEL MANIFESTATION OF α CLUSTERING
Authors: ASTIER ALAIN , PETKOV PAVEL , PORQUET MARIE-GENEVIÈVE , DELION DORU S. , SCHUCK PETER
Published: July 2010

Excited states in 212 Po have been populated by α transfer using the 208 Pb (18 O ,14 C ) reaction and studied with the Euroball γ multidetector array. Very enhanced E1 transitions have been revealed by very short lifetimes measured by the DSAM method, found in the [0.1-1.4] ps range. The emitting states, which have non-natural parity values, are the fingerprints of the "α-208 Pb " structure present in 212 Po .