37,312 research outputs found
Notes on the Biology of \u3ci\u3eSaperda Imitans\u3c/i\u3e Infesting Wind-Damaged Black Cherry in Allegheny Hardwood Stands
This paper reports observations made on the life history and biology of Saperda imitans Felt & Joutel in black cherry, Prunus serotina Ehrh. S. imitans was the principle longhorned beetle (Coleoptera: Cerambycidae) reared from bolts collected from 68 wind-thrown black cherry at the Kane Experimental Forest in northwestern Pennsylvania. It was also the only species that overwintered in the sapwood/outer heartwood, and thus impacted the commercial value of these trees. Gaurotes cyanipennis (Say) was the only other cerambycid reared from caged bolts taken from wind-thrown black cherry. The cerambycids Stenocorus vittiger (Randall), Arthophylax attenuatus (Haldman), G. cyanipennis, Neoclytus acuminatus acuminatus (F.), Clytus ruricola (Olivier), Cyrtophorus verrucosus (Olivier), and Astylopsis macula (Say) were captured in ethanol-baited Lindgren® funnel traps placed in wind-thrown stands, but were not reared from cherry logs. S. imitans was not caught in these traps and apparently it is not attracted to ethanol baits. Neither S. imitans nor G. cyanipennis were reared from completely uprooted trees (dead) or trees with a major portion of the root system still embedded in soil (live). Preferred hosts were black cherry with moist phloem and epicormic branches with \u3c25% live foliage (dying). The density of S. imitans galleries was similar for dying trees in each of three diameter classes; 20-30 cm, \u3e30-40 cm, \u3e40cm. Samples taken from the upper half of the first 5 m of black cherry boles had a higher density of galleries than did those from the lower half. The beetle was recovered in low numbers from branches \u3c10 cm in basal diameter. S. imitans is univoltine and in 2007 peak emergence of adults occurred from late May to early June. Results identified the condition of wind-damaged black cherry most susceptible to an infestation of S. imitans. This information can be used to establish salvage priorities following a weather event such as this
Study of ball bearing torque under elastohydrodynamic lubrication
Spinning and rolling torques were measured in an angular-contact ball bearing with and without a cage under several lubrication regimes in a modified NASA spinning torque apparatus. Two lubricants were used, a di-2 ethylhexyl sebacate and a synthetic paraffinic oil, at shaft speeds of 1000, 2000, and 3000 rpm and bearing loads from 10 lbs to 90 lbs. An analytical model was developed from previous spinning friction models to include rolling with spinning under lubrication regimes from thin film to flooded conditions. The bearing torque values have a wide variation, under any condition of speed and load, depending on the amount of lubricant present in the bearing. The analytical model compared favorably with experimental results under several lubrication regimes
New generalized rheological model for lubrication of a ball spinning in a nonconforming groove
The elastohydrodynamic theory for predicting the spinning friction of a ball in a nonconforming groove was modified to incorporate a rheological model. The rheological model is based on the exponential pressure viscosity relation for low shear stresses, but at high shear rates and pressures, the relation is altered to one in which the shear stress is porportional to the normal stress. The model was fitted to experimental spinning torques for four different lubricants: a synthetic paraffinic lubricant, di-2-ethylhexyl sebacate, a super-refined naphthenic mineral oil, and a polyphenyl ether (5P4E). Good agreement between the model and experiment was found
AMERICA'S FORGOTTEN PEOPLE AND PLACES: ENDING THE LEGACY OF POVERTY IN THE RURAL SOUTH
This study focuses on the longstanding impoverishment of the rural South and three of its subregions-Appalachia, the Mississippi Delta, and the Black Belt. The poor quality of life in rural Appalachia and along the Mississippi Delta has been publically acknowledged by programs and commissions for improving conditions. However, the more comprehensive Black Belt subregion that links parts of Southern Appalachia and the Southern Delta has not received such regional policy attention. While the South as a whole is more rural and impoverished than other U.S. regions, this is largely due to the poor conditions in the Black Belt. In addition to region and rurality, a third feature of the pattern is race. It is in the Black Belt that the South's poor socioeconomic conditions are most concentrated. Policy and program attention are needed for regional solutions that take rurality and race into account along with demographic and other subregional characteristics.Appalachia, Black Belt, Mississippi Delta, policy, poverty, quality of life, rural, South, Community/Rural/Urban Development,
Effect of surface roughness on rate-dependent slip in simple fluids
Molecular dynamics simulations are used to investigate the influence of
molecular-scale surface roughness on the slip behavior in thin liquid films.
The slip length increases almost linearly with the shear rate for atomically
smooth rigid walls and incommensurate structures of the liquid/solid interface.
The thermal fluctuations of the wall atoms lead to an effective surface
roughness, which makes the slip length weakly dependent on the shear rate. With
increasing the elastic stiffness of the wall, the surface roughness smoothes
out and the strong rate dependence is restored again. Both periodically and
randomly corrugated rigid surfaces reduce the slip length and its shear rate
dependence.Comment: 15 pages, 5 figures; submitted to J. Chem. Phy
Paraelectric and ferroelectric order in two-state dipolar fluids
Monte Carlo simulations are used to examine cooperative creation of polar
state in fluids of two-state particles with nonzero dipole in the excited
state. With lowering temperature such systems undergo a second order transition
from nonpolar to polar, paraelectric phase. The transition is accompanied by a
dielectric anomaly of polarization susceptibility increasing by three orders of
magnitude. The paraelectric phase is then followed by formation of a nematic
ferroelectric which further freezes into an fcc ferroelectric crystal by a
first order transition. A mean-field model of phase transitions is discussed.Comment: 5 pages, 4 figure
A New Waveform Consistency Test for Gravitational Wave Inspiral Searches
Searches for binary inspiral signals in data collected by interferometric
gravitational wave detectors utilize matched filtering techniques. Although
matched filtering is optimal in the case of stationary Gaussian noise, data
from real detectors often contains "glitches" and episodes of excess noise
which cause filter outputs to ring strongly. We review the standard \chi^2
statistic which is used to test whether the filter output has appropriate
contributions from several different frequency bands. We then propose a new
type of waveform consistency test which is based on the time history of the
filter output. We apply one such test to the data from the first LIGO science
run and show that it cleanly distinguishes between true inspiral waveforms and
large-amplitude false signals which managed to pass the standard \chi^2 test.Comment: 10 pages, 6 figures, submitted to Classical and Quantum Gravity for
the proceedings of the Eighth Gravitational Wave Data Analysis Workshop
(GWDAW-8
Conceptual information processing: A robust approach to KBS-DBMS integration
Integrating the respective functionality and architectural features of knowledge base and data base management systems is a topic of considerable interest. Several aspects of this topic and associated issues are addressed. The significance of integration and the problems associated with accomplishing that integration are discussed. The shortcomings of current approaches to integration and the need to fuse the capabilities of both knowledge base and data base management systems motivates the investigation of information processing paradigms. One such paradigm is concept based processing, i.e., processing based on concepts and conceptual relations. An approach to robust knowledge and data base system integration is discussed by addressing progress made in the development of an experimental model for conceptual information processing
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