No description available.

The phenomenon of somatosensory attenuation describes the perception that self-generated touch feels weaker than externally generated touch of identical intensity. Previous studies have shown that besides intensity, self-generated touches feel less pleasant and less ticklish than identical externally generated touches. However, previous studies did not systematically assess attenuation across a range of stimuli that can elicit intensity, pleasantness, and ticklishness more efficiently. This thesis aims to replicate these previous observations across a range of tactile stimuli of different intensities and velocities and investigate whether people who attenuate their self-generated touches to a greater extent do so for all aforementioned qualities. Previous studies have shown that participants with lower levels of somatosensory attenuation have more schizotypal personality traits. Twelve volunteers participated in three perceptual tasks where they received touches on their sole generated either by a robot(External) or the participants(Self). Following the strokes, participants had to rate the sensation from 0(not at all) to 100(extremely). For the intensity task, we manipulated the intensity of the applied forces (1,2,3,4N). For the pleasantness and ticklishness tasks, we manipulated the velocity of the applied strokes (0.3,1,10,30cm/s). After the tasks, participants completed a Schizotypal Personality Questionnaire (SPQ). Significant somatosensory attenuation was observed in all tasks, but for specific, not all, stimuli: forces of 4N in terms of intensity, strokes of 1cm/s in terms of pleasantness, and strokes of 10cm/s and 30cm/s in terms of ticklishness. These results suggest that the ability to suppress the tactile consequences of self-generated touch occurs in all three tactile qualities.

Oyster reefs provide valuable ecosystemservices that contribute to coastal resilience. Unfortunately, many reefs have been degraded or removed completely, and there are increased efforts to restore oysters in many coastal areas. In particular, much attention has recently been given to the restoration of shellfish reefs along eroding shorelines to reduce erosion. Such fringing reef approaches, however, often lack empirical data to identify locations where reefs are most effective in reducing marsh erosion, or fully take into account habitat suitability. Using monitoring data from 5 separate fringing reef projects across coastal Louisiana, we quantify shoreline exposure (fetch + wind direction + wind speed) and reef impacts on shoreline retreat. Our results indicate that fringing oyster reefs have a higher impact on shoreline retreat at higher exposure shorelines. At higher exposures, fringing reefs reduced marsh edge erosion an average of 1.0 m y-1. Using these data, we identify ranges of shoreline exposure values where oyster reefs are most effective at reducing marsh edge erosion and apply this knowledge to a case study within one Louisiana estuary. In Breton Sound estuary, we calculate shoreline exposure at 500 random points and then overlay a habitat suitability index for oysters. This method and the resulting visualization show areas most likely to support sustainable oyster populations as well as significantly reduce shoreline erosion. Our results demonstrate how site selection criteria, which include shoreline exposure and habitat suitability, are critical to ensuring greater positive impacts and longevity of oyster reef restoration projects.

This thesis focuses on the theory, fabrication, and characterization of 2-port surface acoustic wave (SAW) resonators, as well as the application of their Fabry-Pérot resonance modes for strain sensing. The thesis includes three articles. In the first article, a fabrication method for high frequency SAW devices using traditional UV photolithography equipment is developed. It is well known that SAW sensors become more sensitive at higher frequencies but realizing high frequency devices requires small features which challenge existing photolithography methods. The proposed process is a modified version of a previously reported tri-layer lift-off photolithography process intended for Si or SiO2 substrates which allows for compatibility with materials that are piezoelectric and pyroelectric, often used as the substrate in SAW devices. The process uses a lithographic tri-layer consisting of layers of lift-off resist (LOR) on the bottom, back anti-reflection coating (BARC) in the middle, and photoresist (PR) on top, improving resolution by a factor of two over traditional lift-off photolithography techniques. We demonstrate the fabrication of a SAW device with an interdigital transducer (IDT) pitch of 4 μm (minimum feature size of 1 μm) on 128o Y-X cut lithium niobate, whose operating frequency is measured as 994.5 MHz. The 2-Port SAW devices that are used in subsequent chapters are fabricated using this process. The second article proposes a method of analyzing acoustic Fabry-Pérot spectra, by analogy with optical cavities, to determine key SAW parameters. In our experiment, 2-port SAW resonators, consisting of two interdigital transducers (IDTs) laterally separated by a free surface cavity length, are used to generate SAWs on 128o Y-X lithium niobate that are trapped between the two IDTs which also act as Bragg reflectors. Fabry-Pérot cavity peaks can be observed through the electrical S11 (reflection) spectrum measured on one IDT, hence a 2-Port resonator is equivalent to an acoustic Fabry-Pérot cavity/resonator. Measurements of the free spectral range and linewidths are then fitted to linear models to obtain the free surface velocity and attenuation of SAW waves, as well as the reflection of interdigital transducers (IDTs), all of which are crucial design parameters. Our method of analyzing Fabry-Pérot spectra provides a convenient method for determining key characteristics of SAW waves and cavities. In the third article, a surface acoustic wave (SAW) strain sensor based on measuring acoustic Fabry-Pérot resonance peaks from a 2-port SAW resonator is demonstrated. A theoretical analysis is proposed to estimate the frequency sensitivity to strain of IDT and cavity resonances and to predict strain distributions in both the cavity and IDT regions of a 2-port SAW resonator bonded to a tapered cantilever beam. The frequency stability of cavity resonance peaks for fabricated 2-port SAW resonators of different cavity length are measured and analyzed to determine the cavity length which exhibits maximum frequency stability. A cross-correlation analysis technique is then introduced to improve the detection of the frequency shift of SAW resonances and enable multimode frequency shift detection. The measured frequency sensitivity to strain of the cavity resonances of a resonator 10 mm in length (operating frequency = 97.7 MHz) was found to be -103.2 ± 0.2 Hz/με while demonstrating excellent linearity (R2 = 0.9999). By considering a minimum signal to noise ratio (SNR) of 3 dB, the device exhibits a minimum strain resolution of only 234 nε.

A series of small- to moderate-sized earthquakes occurred in Arkansas, Oklahoma and Texas from 2010 to 2012, coinciding with the arrival of the EarthScope Transportable Array (TA). The data the TA recorded from those earthquakes provide a unique opportunity to study attenuation of the Lg phase in the mid-continent and Gulf Coastal region. The TA data reveal previously unrecognized regional variability of ground motion propagation in the central United States. A study of the Fourier amplitude spectra shows the Lg phase exhibiting strong attenuation for ray paths from Arkansas, southwest through the Ouachita Orogenic Belt and into central Texas, and south into the Gulf Coastal region. Less attenuation is seen in central Texas for ray paths extending directly south from Oklahoma, though attenuation remains strong along the Gulf Coast. In contrast, ray paths to the north, regardless of source location, exhibit very little attenuation, especially in northern Missouri and southern Iowa. Regression models that incorporate near-receiver (distance-independent) attenuation due to thick sediments in the Gulf Coastal Plain successfully reduce path-related bias in the regression residuals for stations near the Gulf Coast. Dividing the central United States into three regions (the Gulf Coastal Plain, the Great Plains and the Midwest) further reduced bias, and allowed for the development of Q models in the Gulf Coastal Plain and the Great Plains. In the Gulf Coastal Plain, the Q model for that part of the ray path through the basement, from the earthquake to the base of the sediment deposits below the receiver, was found to be Q=(295±11)*f^(0.645±0.029). The model for attenuation in the sediment section near the receiver in the Gulf Coastal Plain is Q=(72±6.7)*f^(0.32±0.06) (velocity through the sediments is unconfirmed but thought to be approximately 1 km/s). The Q model for the Great Plains is  Q=(692±61.3)*f^(0.43±0.07). The Midwest region exhibited extremely complicated behavior: the data indicate little or no attenuation of amplitudes in the frequency band from approximately 0.7 to 2.0 Hz. As a consequence, Q in the Midwest region in that frequency range could not be realistically determined. / Master of Science

No description available.

Lifetimes of highly excited states in the semi-magic (N=50) nucleus 94Ru were deduced from an analysis of the Doppler broadened transition line shapes. Excited states in 94Ru were populated in the 58Ni(40Ca, 4p)94Ru∗ fusion-evaporation reaction at the Grand Accélérateur National d’Ions Lourds (GANIL) accelerator complex situated in Caen, France. Doppler Shift Attenuation Method (DSAM) lifetime analysis was performed on the Doppler broadened peaks in energy spectra from γ-rays emitted while the residual nuclei were slowing down in a thick 6 mg/cm2 metallic 58Ni target. In total eight excited-state lifetimes in the angular momentum range I = (13 − 20)ħ have been measured, five of which were determined for the first time. The deduced corresponding B(M1) and B(E2) reduced transition strengths are discussed within the framework of large-scale shell model calculations. / Livstider för exciterade tillstånd i den semimagiska (N = 50) atomkärnan 94Ru har uppmätts från en analys av Doppler-breddade övergångslinjer. Exciterade tillstånd i 94Ru har populerats i 58Ni(40Ca, 4p)94Ru∗ fusion-evaporationsreaktioner vid partikelacceleratorn Grand Accélérateur National d’Ions Lourds (GANIL), Caen, Frankrike. Livstidsanalys utfördes med hjälp av Dopplerskiftsattenueringsmetoden (DSAM) på linjer i energispektra uppmätta från gammastrålning som emitterades medan de högt exciterade atomkärnorna bromsades ned i ett homogent metalliskt strålmål av 6 mg/cm2 tjocklek. Mätmetoden har verifierats med hjälp av data från en mätning utförd med en alternativ metod. Livstider för sammanlagt åtta exciterade tillstånd i spinn-intervallet I = (13 − 20)ħ har uppmätts, varav fem bestämdes för första gången. Ur dessa har härletts B(M1) och B(E2) övergångssannolikheter vilka diskuteras inom ramen för storskaliga skalmodellsberäkningar. / <p>QC 20171110</p>

No description available.

AUCTORITAS Projektstyrning AB arbetar med att få fram förfrågningsunderlag för två nya flerbostadshus i en miljö som är bullerutsatt. Ett problem som uppstått är att hitta en utfackningsvägg som klarar kraven för buller samt U-värde som samtidigt är ekonomisk försvarbar. Författarna har på uppdrag av AUCTORITAS Projektstyrning AB undersökt 10 olika utfackningsväggar med hänsyn till ljudreduktion, U-värde samt pris. Syftet med arbetet var att utreda de tekniska egenskaperna för utfackningsväggarna. Frågeställningen som behandlades var följande: Hur påverkar olika materialval ljuddämpningen? Vilka utfackningsväggar klarar bullerkraven vid en nybyggnation på Albyberget? Kan problematiken lösas enbart med väggarna eller krävs det ytterligare åtgärder? Är det ekonomiskt försvarbart att välja en tjockare vägg med hänsyn till u-värde istället för att maximera BOA? För att besvara dessa frågor har författarna genomfört laborationer, litteraturstudier samt tagit del av ett referensobjekt, akustikrapporter, energiberäkningsrapporter och kalkylböcker/offerter. Intervju med en person som besitter kunskap inom området buller/akustik har utförts och använts som kompletterande underlag. Resultatet ledde till att en standard träregelvägg på 395 mm som uppfyllde samtliga projektkrav som samtidigt var ekonomisk försvarbar med en kostnad på 1 391 kr/m2 rekommenderades till flerbostadshusen på Albyberget / AUCTORITAS Projektstyrning AB is working on obtaining contract documents for two new apartment buildings in an environment that is exposed to noise. One problem that has arisen is to find an infill wall that meets the requirements for noise and U-value, which at the same time is economically justifiable. The authors, on behalf of AUCTORITAS Projektstyrning AB, have examined 10 different infill walls with regard to noise reduction, U-value and price. The purpose of the work was to investigate the technical properties of the infill walls. The question that was addressed was the following: How does different materials affect the sound attenuation? Which infill walls can handle the noise requirements of a new construction on Albyberget? Can the problem be solved solely with the walls or does it require further action? Is it economically justifiable to choose a thicker wall with regard to u value instead of maximizing the living space? In order to answer these questions, the authors have carried out laboratory work, literature studies and also taken part in a reference object, acoustics reports, energy calculation reports and costing books/offers. An interview with a person with knowledge in the area of noise/acoustics have been completed and used as a complementary basis. The results led to a recommendation of a standard timber frame wall with a thickness of 395 mm, that met all of the project requirements and with a cost of 1 391 kr/m2 to be used in the buildings at Albyberget.

Coastal counties make up only 17% of the land area in the continental United States, yet 53% of the nation’s population resides in these locations. With sea level rise, erosion, and human disturbances all effecting coastal areas, researchers are working to find strategies to protect and stabilize current and future shorelines. In order to maintain shoreline stability while maintaining intertidal habitat, multipurpose living shorelines have been developed to mimic natural shoreline assemblages while preventing erosion. This project determined the effectiveness of a living shoreline stabilization containing Crassostrea virginica (eastern oyster) and Spartina alterniflora (smooth cordgrass) in the field and through controlled wave tank experiments. First, fringing oyster reefs constructed of stabilized oyster shell and smooth cordgrass plugs were placed along three eroding shoreline areas (shell middens) within Canaveral National Seashore (CANA), New Smyrna Beach, FL. For each shell midden site, four treatments (bare shoreline control, oyster shell only, S. alterniflora only, and oyster shell + S. alterniflora) were tested in replicate 3.5 x 3.5 meter areas in the lower and middle intertidal zones. Each treatment was replicated five times at each site; erosion stakes within each replicate allowed measurement of changes in sedimentation. After one year in the field, the living shoreline treatments that contained oyster shells (oyster shell only and oyster shell + S. alterniflora) vertically accreted on average 4.9 cm of sediment at two of the sites, and an average of 2.9 cm of sediment at the third, while the controls lost an average of 0.5 cm of sediment. S. alterniflora did not significantly contribute to the accretion at any site due to seagrass wrack covering and killing plants within one month of deployment. Next, the reduction in wave energy caused by these living shoreline stabilization techniques relative to bare sediment (control) was quantified. The energy reduction immediately after deployment, and the change in energy reduction when S. alterniflora had been allowed to grow for one year, and the stabilized shell was able to recruit oysters for one year was tested. Laboratory experiments were conducted in a nine-meter long wave tank using capacitance wave gauges to ultimately measure changes in wave height before and after treatments. Wave energy was calculated for each newly deployed and one-year old shoreline stabilization treatment. Boat wake characteristics from CANA shorelines were measured in the field and used as inputs to drive the physical modeling. Likewise, in the wave tank, the topography adjacent to the shell midden sites was measured and replicated. Oyster shell plus S. alterniflora attenuated significantly more wave energy than either the shells or plants alone. Also, one-year old treatments attenuated significantly more energy than the newly deployed treatments. The combination of one-year old S. alterniflora plus live oysters reduced 67% of the wave energy. With the information gathered from both the field and wave experiments, CANA chose to utilize living shorelines to stabilize three shell middens within the park. Oyster shell, marsh grass and two types of mangroves (Rhizophora mangle, Avicennia germinans) were deployed on the intertidal zones of the eroding middens. Significant accretion occurred at all middens. Two sites (Castle Windy and Garver Island) vertically accreted an average 2.3 cm of sediment after nine months, and six months respectively, and the other site (Hong Kong) received on average 1.6 cm of sediment after six months. All control areas (no stabilization) experienced sediment loss, with erosion up to 5.01 cm at Hong Kong. Plant survival was low ( < 20%) at Castle Windy and Garver Island, while Hong Kong had moderate survival (48-65%). Of the surviving marsh iv grass and mangroves on the three sites, almost all ( > 85%) had documented growth in the form of increased height or the production on new shoots. Landowners facing shoreline erosion issues, including park managers at CANA, can use this information in the future to create effective shoreline stabilization protocols. Even though the techniques will vary from location to location, the overall goal of wave attenuation while maintaining shoreline habitat remains. As the research associated with the effectiveness of living shorelines increases, we hope to see more landowners and land managers utilize this form of soft stabilization to armor shorelines.