9,240 research outputs found
Dutch listeners' use of suprasegmental cues to English stress
Dutch listeners outperform native listeners in identifying syllable stress in English. This is because lexical stress is more useful in recognition of spoken words of Dutch than of English, so that Dutch listeners pay greater attention to stress in general. We examined Dutch listeners’ use of the acoustic correlates of English stress. Primary- and secondary-stressed syllables differ significantly on acoustic measures, and some differences, in F0 especially, correlate with data of earlier listening experiments. The correlations found in the Dutch responses were not paralleled in data from native listeners. Thus the acoustic cues which distinguish English primary versus secondary stress are better exploited by Dutch than by native listeners
A trapped mercury 199 ion frequency standard
Mercury 199 ions confined in an RF quadrupole trap and optically pumped by mercury 202 ion resonance light are investigated as the basis for a high performance frequency standard with commercial possibilities. Results achieved and estimates of the potential performance of such a standard are given
Language-universal constraints on the segmentation of English
Two word-spotting experiments are reported that examine whether the Possible-Word Constraint (PWC) [1] is a language-specific or language-universal strategy for the segmentation of continuous speech. The PWC disfavours parses which leave an impossible residue between the end of a candidate word and a known boundary. The experiments examined cases where the residue was either a CV syllable with a lax vowel, or a CVC syllable with a schwa. Although neither syllable context is a possible word in English, word-spotting in both contexts was easier than with a context consisting of a single consonant. The PWC appears to be language-universal rather than language-specific
The information content of gravitational wave harmonics in compact binary inspiral
The nonlinear aspect of gravitational wave generation that produces power at
harmonics of the orbital frequency, above the fundamental quadrupole frequency,
is examined to see what information about the source is contained in these
higher harmonics. We use an order (4/2) post-Newtonian expansion of the
gravitational wave waveform of a binary system to model the signal seen in a
spaceborne gravitational wave detector such as the proposed LISA detector.
Covariance studies are then performed to determine the ultimate accuracy to be
expected when the parameters of the source are fit to the received signal. We
find three areas where the higher harmonics contribute crucial information that
breaks degeneracies in the model and allows otherwise badly-correlated
parameters to be separated and determined. First, we find that the position of
a coalescing massive black hole binary in an ecliptic plane detector, such as
OMEGA, is well-determined with the help of these harmonics. Second, we find
that the individual masses of the stars in a chirping neutron star binary can
be separated because of the mass dependence of the harmonic contributions to
the wave. Finally, we note that supermassive black hole binaries, whose
frequencies are too low to be seen in the detector sensitivity window for long,
may still have their masses, distances, and positions determined since the
information content of the higher harmonics compensates for the information
lost when the orbit-induced modulation of the signal does not last long enough
to be apparent in the data.Comment: 13 pages, 5 figure
Large-Scale Advanced Prop-Fan (LAP) pitch change actuator and control design report
In recent years, considerable attention has been directed toward improving aircraft fuel consumption. Studies have shown that the high inherent efficiency previously demonstrated by low speed turboprop propulsion systems may now be extended to today's higher speed aircraft if advanced high-speed propeller blades having thin airfoils and aerodynamic sweep are utilized. Hamilton Standard has designed a 9-foot diameter single-rotation Large-Scale Advanced Prop-Fan (LAP) which will be tested on a static test stand, in a high speed wind tunnel and on a research aircraft. The major objective of this testing is to establish the structural integrity of large-scale Prop-Fans of advanced construction in addition to the evaluation of aerodynamic performance and aeroacoustic design. This report describes the operation, design features and actual hardware of the (LAP) Prop-Fan pitch control system. The pitch control system which controls blade angle and propeller speed consists of two separate assemblies. The first is the control unit which provides the hydraulic supply, speed governing and feather function for the system. The second unit is the hydro-mechanical pitch change actuator which directly changes blade angle (pitch) as scheduled by the control
Carbon Free Boston: Waste Technical Report
Part of a series of reports that includes:
Carbon Free Boston: Summary Report;
Carbon Free Boston: Social Equity Report;
Carbon Free Boston: Technical Summary;
Carbon Free Boston: Buildings Technical Report;
Carbon Free Boston: Transportation Technical Report;
Carbon Free Boston: Energy Technical Report;
Carbon Free Boston: Offsets Technical Report;
Available at http://sites.bu.edu/cfb/OVERVIEW:
For many people, their most perceptible interaction with their environmental footprint is through the
waste that they generate. On a daily basis people have numerous opportunities to decide whether to
recycle, compost or throwaway. In many cases, such options may not be present or apparent. Even
when such options are available, many lack the knowledge of how to correctly dispose of their waste,
leading to contamination of valuable recycling or compost streams. Once collected, people give little
thought to how their waste is treated. For Boston’s waste, plastic in the disposal stream acts becomes a
fossil fuel used to generate electricity. Organics in the waste stream have the potential to be used to
generate valuable renewable energy, while metals and electronics can be recycled to offset virgin
materials. However, challenges in global recycling markets are burdening municipalities, which are
experiencing higher costs to maintain their recycling.
The disposal of solid waste and wastewater both account for a large and visible anthropogenic impact
on human health and the environment. In terms of climate change, landfilling of solid waste and
wastewater treatment generated emissions of 131.5 Mt CO2e in 2016 or about two percent of total
United States GHG emissions that year. The combustion of solid waste contributed an additional 11.0 Mt
CO2e, over half of which (5.9 Mt CO2e) is attributable to the combustion of plastic [1]. In Massachusetts,
the GHG emissions from landfills (0.4 Mt CO2e), waste combustion (1.2 Mt CO2e), and wastewater (0.5
Mt CO2e) accounted for about 2.7 percent of the state’s gross GHG emissions in 2014 [2].
The City of Boston has begun exploring pathways to Zero Waste, a goal that seeks to systematically
redesign our waste management system that can simultaneously lead to a drastic reduction in emissions
from waste. The easiest way to achieve zero waste is to not generate it in the first place. This can start at
the source with the decision whether or not to consume a product. This is the intent behind banning
disposable items such as plastic bags that have more sustainable substitutes. When consumption occurs,
products must be designed in such a way that their lifecycle impacts and waste footprint are considered.
This includes making durable products, limiting the use of packaging or using organic packaging
materials, taking back goods at the end of their life, and designing products to ensure compatibility with
recycling systems. When reducing waste is unavoidable, efforts to increase recycling and organics
diversion becomes essential for achieving zero waste. [TRUNCATED]Published versio
Interview with Eliot Cutler by Mike Hastings
Biographical NoteEliot Raphael Cutler was born in 1946 in Bangor, Maine. His mother was an economist and his father, a physician, was responsible for the reorganization of the Maine university system; the Cutler Health Center in Orono, Maine, is named in his honor. As a sophomore in high school, Eliot transferred from Bangor High School to Deerfield Academy. He attended Harvard University and Georgetown Law School. While at Harvard he was involved with the Harvard Lampoon. He worked as a legislative assistant and clerk for Senator Muskie from 1967 to 1972 and was a senior staff person at the OMB during the Carter administration. He has served on the Board of Visitors of the Muskie School for Public Service at University of Southern Maine in Portland, Maine. At the time of this Interview, he was a member of the law firm of Akin, Gump, Strauss, Hauer & Feld, LLP.
SummaryInterview includes discussion of: Cutler’s candidacy for governor; campaigns Cutler has worked on, including those for Muskie, Carter, and Mondale; Cutler’s connection to China; Cutler’s role as chairman of the Board of Visitors at the Muskie School; political attention to energy issues under Carter and today; Cutler\u27s meeting George Mitchell as an intern in Muskie’s office; how Mitchell’s operating style differed from Muskie’s; Cutler’s role as press secretary in 1968 and contact with the media; Mitchell’s role in Muskie’s fund-raising in 1968 and 1972; the 1972 campaign; Muskie as a negotiator; Mitchell’s role in Ireland and the Middle East; and Marshall Stern
Effects of finite arm-length of LISA on analysis of gravitational waves from MBH binaries
Response of an interferometer becomes complicated for gravitational wave
shorter than the arm-length of the detector, as nature of wave appears
strongly. We have studied how parameter estimation for merging massive black
hole binaries are affected by this complicated effect in the case of LISA. It
is shown that three dimensional positions of some binaries might be determined
much better than the past estimations that use the long wave approximation. For
equal mass binaries this improvement is most prominent at \sim 10^5\sol.Comment: 10 pages, 3 figures, to appear in Phys.Rev.
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