16,446 research outputs found
Diamond growth in premixed propylene-oxygen flames
Diamond film growth in low-pressure premixed propylene/oxygen flames is demonstrated. Well-faceted films are grown at a pressure of 180 Torr and a fuel/oxygen ratio of 0.47. Using propylene as the fuel may greatly improve the economics of flame synthesis of diamond, since propylene is an order of magnitude cheaper than acetylene
Diamond films from combustion of methyl acetylene and propadiene
To date diamond films grown with the combustion technique have used either acetylene or, rarely, ethylene as the fuel. However, there are barriers to large scale commercialization of the combustion technique using either fuel. For example, acetylene is relatively expensive and difficult to handle, while the use of ethylene gives relatively low growth rates. In this letter we propose replacing acetylene with MAPPTM gas, a commercial mixture of methyl acetylene and propadiene in liquefied petroleum gas (primarily propylene). MAPP gas is considerably cheaper, safer, and easier to handle than acetylene. Furthermore, the experiments described here suggest that MAPP gas flames are only slightly less efficient than acetylene flames at converting fuel carbon atoms into diamond
A People's History Of Recent Urban Transportation Innovation
Who are the people leading the charge in urban transportation? As our report explains, the short answer is that it takes leaders from three different sectors of urban society to make change happen quickly.First, there needs to be a robust civic vanguard, the more diverse their range of skills and participation, the better. Second, mayors, commissioners and other city leaders need to create the mandate and champion the change. The third sector is the agency staff. When these three sectors align, relatively quick transformation is possible. Several cities, including New York and Pittsburgh, recently experienced this alignment of a healthy civic community, a visionary and bold mayor and transportation head, and internal agency champions. Our report also highlighted the potential of other cities, such as Charlotte, where the civic sector continues to build on and widen their base
Measuring producer welfare under output price uncertainty and risk non-neutrality
Procedures to measure the producer welfare effects of changes in an output price distribution under uncertainty are reviewed. Theory and numerical integration methods are combined to show how for any form of Marshallian risk-responsive supply, compensating variation of a change in higher moments of an output price distribution can be derived numerically. The numerical procedure enables measurement of producer welfare effects in the many circumstances in which risk and uncertainty are important elements. The practical ease and potential usefulness of the procedure is illustrated by measuring the producer welfare effects of USA rice policy.price uncertainty, risk non-neutrality, welfare economics, Demand and Price Analysis, Risk and Uncertainty,
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Sleep dysfunction and EEG alterations in mice overexpressing alpha-synuclein.
BackgroundSleep disruptions occur early and frequently in Parkinson's disease (PD). PD patients also show a slowing of resting state activity. Alpha-synuclein is causally linked to PD and accumulates in sleep-related brain regions. While sleep problems occur in over 75% of PD patients and severely impact the quality of life of patients and caregivers, their study is limited by a paucity of adequate animal models.ObjectiveThe objective of this study was to determine whether overexpression of wildtype alpha-synuclein could lead to alterations in sleep patterns reminiscent of those observed in PD by measuring sleep/wake activity with rigorous quantitative methods in a well-characterized genetic mouse model.MethodsAt 10 months of age, mice expressing human wildtype alpha-synuclein under the Thy-1 promoter (Thy1-aSyn) and wildtype littermates underwent the subcutaneous implantation of a telemetry device (Data Sciences International) for the recording of electromyograms (EMG) and electroencephalograms (EEG) in freely moving animals. Surgeries and data collection were performed without knowledge of mouse genotype.ResultsThy1-aSyn mice showed increased non-rapid eye movement sleep during their quiescent phase, increased active wake during their active phase, and decreased rapid eye movement sleep over a 24-h period, as well as a shift in the density of their EEG power spectra toward lower frequencies with a significant decrease in gamma power during wakefulness.ConclusionsAlpha-synuclein overexpression in mice produces sleep disruptions and altered oscillatory EEG activity reminiscent of PD, and this model provides a novel platform to assess mechanisms and therapeutic strategies for sleep dysfunction in PD
Application of graphics processing units to search pipelines for gravitational waves from coalescing binaries of compact objects
We report a novel application of a graphics processing unit (GPU) for the purpose of accelerating the search pipelines for gravitational waves from coalescing binaries of compact objects. A speed-up of 16-fold in total has been achieved with an NVIDIA GeForce 8800 Ultra GPU card compared with one core of a 2.5 GHz Intel Q9300 central processing unit (CPU). We show that substantial improvements are possible and discuss the reduction in CPU count required for the detection of inspiral sources afforded by the use of GPUs
Test Set Diameter: Quantifying the Diversity of Sets of Test Cases
A common and natural intuition among software testers is that test cases need
to differ if a software system is to be tested properly and its quality
ensured. Consequently, much research has gone into formulating distance
measures for how test cases, their inputs and/or their outputs differ. However,
common to these proposals is that they are data type specific and/or calculate
the diversity only between pairs of test inputs, traces or outputs.
We propose a new metric to measure the diversity of sets of tests: the test
set diameter (TSDm). It extends our earlier, pairwise test diversity metrics
based on recent advances in information theory regarding the calculation of the
normalized compression distance (NCD) for multisets. An advantage is that TSDm
can be applied regardless of data type and on any test-related information, not
only the test inputs. A downside is the increased computational time compared
to competing approaches.
Our experiments on four different systems show that the test set diameter can
help select test sets with higher structural and fault coverage than random
selection even when only applied to test inputs. This can enable early test
design and selection, prior to even having a software system to test, and
complement other types of test automation and analysis. We argue that this
quantification of test set diversity creates a number of opportunities to
better understand software quality and provides practical ways to increase it.Comment: In submissio
2-Hydroxy-3-methoxybenzaldehyde (o-vanillin) revisited
The structure of ortho-vanillin, C[subscript 8]H[subscript 8]O[subscript 3], has been revisited with modern methods and at low temperature (100 K). The previous structure [Iwasaki et al. (1976). Acta Cryst. B32, 1264-1266] is confirmed, but geometric precision is improved by an order of magnitude. The C atom of the methoxy group lies close to the benzene ring plane, which is the most common geometry for -OMe groups lying ortho to -OH groups on an aromatic ring. The crystal structure displays one intramolecular O-H...O and three weak intermolecular C-H...O hydrogen bonds
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