Observations of High Frequency, Long Range Acoustic Propagation in a Harbor Environment

The positioning and navigation of AUV\u27s in harbor environments using underwater acoustics is complicated by shallow waters, long propagation distances, and complex oceanographic features. This paper reports on high frequency (40 kHz) acoustic measurements made in Portsmouth Harbor, NH, USA, which is an estuary containing several riverine inputs and a strong tidal flow (2+ knots). A one-way propagation experiment was conducted at the mouth of the harbor for propagation distances up to 100 water depths. Strong signatures of a variety of phenomenon were observed in the acoustic signal levels, including tidal heights and currents, turbulent mixing, and wind/wave action. The relative importance of each of these will be discussed in terms of signal to noise level and the associated constraints on acoustic positioning systems

Revealing Electronic Coupling in Semiconductor Quantum Dot Networks by Electrochemistry

Eine Auswahl an gekoppelten hybriden Nanostrukturen (COIN) wurde elektrochemisch untersucht. Dabei wurden zwei spezialisierte Methoden implementiert und ihr Potential für die Bestimmung der Grenzorbitale und der elektronischen Kopplung von Quantenpunkten aufgezeigt. Potentialmodulierte Absorptionsspektroskopie (EMAS) ist eine ideale Methode, um die energetische Lage des Leitungsbandes von Halbleiter-Quantenpunkten aufzuklären. In dieser Arbeit wurde sie verwendet um mehr über die Bildung von Hybridorbitalen zwischen CdSe Quantenpunkten und Metall-Phthalocyaninen zu lernen. Elektrochemisches Gating (ECG) ist eine sehr gute Methode um genau das Energielevel aufzeigen zu können, über das der Großteil des Ladungsträger-Transports in COINs stattfindet. Dies konnte erfolgreich an einer Auswahl an COIN-Systemen gezeigt werden, zum Beispiel an mit Terthiophen-Derivaten verlinkten PbS Quantenpunkten und an Amino-substituierten Kupfer-Phthalocyaninen

The Impact of a Fruit and Vegetable Intervention on School Cafeteria Fruit and Vegetable Selection and Consumption in a Rural, Appalachian Mississippi Elementary School

Fruit and vegetable intake for children in the United States is low, which puts them at risk for poor health in the future. The National School Lunch Program meal pattern and nutrition standards for participating schools include increased fruits and vegetables, compared to previous standards. Using a pretest-posttest design, this study examined the effect of a fruit and vegetable intervention on fruit and vegetable food selection and consumption in a rural, Appalachian Mississippi elementary school. A six-week intervention (nutrition education, cafeteria tastings, fruit and vegetables for home usage/backpack program) was implemented. The unannounced fruit and vegetable selection and waste measurements evaluated the identical menu served at both pre- and post-intervention. The menu included raw broccoli florets, raw grape tomatoes, baked French fries, raw red grapes, and canned/frozen peaches. Food selection was measured by calculating the proportion of students selecting each item. At both pre- and post-intervention, 10 servings of each item were weighed prior to lunch. Total served was calculated by multiplying the number of each item served by its average sample weight. All tray items not consumed were weighed, and total waste was calculated relative to amount served. Data were analyzed using a 2-proportion z-score test and paired t-test to compare school-level and school-level per person fruit and vegetable food selected and consumed from pre- to post-intervention. Pre- and post-intervention meals served/measured were 256 and 283, respectively. Only the proportion of students selecting peaches changed (pre, 33%; post, 43%; p=.01468). The percentage selection of fruit and vegetable menu components (mean ± standard deviation) did not significantly change from pre- (45.6 ± 29.8%) to post-intervention (50.9 ± 33.0%) [Mean change, -5.3%; 95% Confidence Interval (CI), -13.6 to 3.1%; t (3) = -1.994; p = .140]. Only French fries consumption increased (p=.00068), and only peach, broccoli, and grape tomato consumption decreased (p\u3c.00001). School-level percentage consumption of fruit and vegetable menu components (mean ± standard deviation) did not significantly change from pre- (57.3 ± 14.4%) to post-intervention (36.2 ± 33.3%) [Mean change, -21.1%; 95% CI, -13.2 to 55.3%; t (4) = 1.709; p = .163]. School-level consumption per person was calculated by dividing the amount of fruit and vegetable components consumed at both pre- and post-intervention by dividing: 1) by the number of reimbursable lunches; and 2) by the number of children who selected that component. School-level (reimbursable lunch method) consumption per person of fruit and vegetable menu components (mean ± standard deviation) did not significantly change from pre- (19.3 ± 18.2g) to post-intervention (17.2 ± 16.9g) [Mean change, 2g; 95% CI, -8 to 12; t (4) = 0.566; p = .602]. School-level consumption per person (selection method) of fruit and vegetable menu components (mean ± standard deviation) did not significantly change from pre- (42.4 ± 42.0g) to post-intervention (27.2 ± 25.7g) [Mean change, 15g; 95% CI, -17 to 47; t (4) = 1.313; p = .259]. A fruit and vegetable intervention was not effective in changing most foods selected or consumed by elementary school children. The short duration of the intervention may have influenced this. More research is needed to determine how to best encourage fruit and vegetable selection and consumption among school children

Economic analysis of alternative applications of an algal production system

A variety of different best management practices are being studied to reduce nutrient pollution in the Chesapeake Bay. The algal turf scrubberTM (ATS) effectively removes nutrients from Bay waters in experimental trials but there is no large-scale applications in the Chesapeake Bay watershed. The purpose of this project was to conduct an economic analysis of the ATS technology to determine the feasibility for nutrient removal across the Bay landscape. Baseline data for the analysis were extrapolated from several small-scale experimental trials of the ATS. The analysis included scaled costs along with benefits from nutrient trading credits, bio-product values of biofuel production, oxygen from photosynthesis and fertilizer value of nutrients taken up in algal growth. Six operating scenarios were analyzed through various cost analyses. The results indicate that the ATS technology can be economically viable under certain conditions and can be complementary to other best management practices for restoration of water quality in the Bay

Wittgenstein and Worship: Investigations of Liturgical Language-Games and Their Formative Role in Christian Identity

I argue that the Christian community’s religious language games, particularly liturgical action (theologia prima) and theological reflection (theologia secunda), mutually shape and correct one another. I demonstrate this using Wittgenstein’s philosophical method, adapting his approach to philosophy for theological use. The first part of this essay explains and demonstrates Wittgenstein’s philosophical method. The second part is an application of his method (with my own adaptation of this method for theology) with Christian liturgy as its subject. The third part of this essay discusses ways in which Wittgenstein’s approach might be adapted further in a fruitful way for theological reflection and catechesis

The Effects of Speech Rate on Comprehension

There is a perception that the rate of speech affects the level of comprehensibility of a listener. If the rate of a speaker during a speech or lecture does in fact affect the level of comprehension, then the speaker would have to modify his/her rate of speech in order to benefit the ears of all his/her listeners. In the present study, 40 participants listened to four passages, taken from www.testpreview.com all recorded at varying speeds, after which they answered 10 questions that corresponded with the passages. Results found that speech rate had no effect on comprehension. However, findings based on one passage suggest that there may be a link between speech rate and content

Acoustic positioning and tracking in Portsmouth Harbour, New Hampshire

Portsmouth Harbor, New Hampshire, is frequently used as a testing area for multibeam and sidescan sonars, and is the location of numerous ground-truthing studies. Having the ability to accurately position underwater sensors is an important aspect of this type of work. However, underwater positioning in Portsmouth Harbor is challenging. It is relatively shallow, approximately one kilometer wide with depths of less than 25 meters. There is mixing between fresh river water and seawater, which is intensified by high currents and strong tides. This causes a very complicated spatial and temporal sound speed structure. Solutions that use the time-of-arrival of an acoustic pulse to estimate range will require very precise knowledge of the travel paths of the signal in order to separate out issues of multipath arrivals. An alternative solution is to use the phase measurements between closely spaced hydrophones to measure the bearing of an acoustic pinger. By using two bearing measurement devices that are widely separated, the intersection of the two bearings can be used to position the pinger. The advantage of this approach is that the sound speed only needs to be known at the location of the phase measurements. Both time-of-arrival and phase difference systems may encounter difficulties arising from horizontal refraction due to spatially varying sound speed. To ascertain which solution would be optimal in Portsmouth Harbor, the time-of-arrival and phase measurement approaches are being examined individually. Initial field tests have been conducted using a 40 kHz signal to look at bearing accuracy. Using hydrophones that are spaced 2/3 wavelengths apart, the bearing accuracy was found to be 1.25deg for angles up to 20deg from broadside with signal to noise ratios (SNR) greater than 15 dB. The results from the closely spaced hydrophones were used to resolve phase ambiguities, allowing finer bearing measurements to be made between hydrophones spaced 5 wavelengths apart. The fi- ne bearing measurements resulted in a bearing accuracy of 0.3deg for angles up to 20deg from broadside with SNR greater than 15 dB. Field tests planned for summer 2007 will include a more detailed investigation of how the environmental influences affect each of the measurement types including range, signal to noise ratio, currents, and sound speed structure

Boron doping of silicon layers grown by liquid phase epitaxy

This paper presents the results of a study of the incorporation of boron into silicon layers grown from a tin melt by liquid phase epitaxy. Boron was added to the melt through the use of boron-doped silicon source wafers. There is a large discrepancy between the amount of boron incorporated into the epitaxial layer and that available in the source wafer. This mismatch is explained by the gradual removal of boron from our system, most likely as a result of boron precipitation in the tin melt. This situation allows for control of the boron profile by adjusting the cooling rate and adding a dwell time. In this way, we have grown an epitaxial layer with an abrupt and highly doped p-type region at the epitaxial layer/substrate interface. This is useful for thin film solar cell applications as it allows the growth of a back surface field and a lightly doped bulk in a single growth step

Vision Zero Oregon

Vision Zero Oregon (VZO) is a street safety philosophy that aims to create streets where no one will be killed or seriously injured. Vision Zero Oregon prioritizes road safety above all else. Every life is worth more than an increase in speeds or road capacity for vehicles. Achieving Vision Zero Oregon goals will require a shift in the focus of policy, laws and enforcement, and the formation of a new relationship between residents and their streets, and revolution in the way transportation departments operate their streets. This project takes on one part of this complex topic, focusing on community interest, involvement, and influence in the transportation system of a neighborhood. The goal is to turn resident interest into activism, and empower a population to support the innovative changes necessary to decisively improve safety. Please visit the website at: http://www.visionzerooregon.org/. This project was conducted under the supervision of Sumner Sharpe and Ellen Bassett