2,664 research outputs found
HEATING COSTS AND HOUSEHOLD WOOD STOVE ACQUISITION: A DISCRETE CHOICE DEMAND MODEL
This paper examines the acquisition of wood stoves by New Hampshire households through use of a utility-maximizing discrete choice model. The analysis is based on the hypothesis that wood stoves are acquired to decrease the monetary costs of home-heating. Operating costs associated with heating with conventional fuel burning capital and with a combination of conventional and wood stove heating capital are estimated. These operating costs are used to estimate probabilities of 1979 wood stove acquisition for particular types of New Hampshire households.Resource /Energy Economics and Policy,
Financial, Managerial, and Attitudinal Characteristics of North Dakota Farm Families: Results of the 1986 Farm Survey
Agricultural Finance, Farm Management,
Identification and Energy Measurements of Light Particles with a CsI(Tl)-Photodiode Combination
This research was sponsored by the National Science Foundation Grant NSF PHY-931478
Tris-N-alkylpyridinium-functionalised cyclotriguaiacylene hosts as axles in branched [4]pseudorotaxane formation
A series of [4]pseudorotaxanes composed of three-way axle threads based on the cyclotriguaiacylene family of crown-shaped cavitands and three threaded macrocyclic components has been achieved. These exploit the strong affinity for electron-poor alkyl-pyridinium units to reside within the electron-rich cavity of macrocycles, in this case dimethoxypillar[5]arene (DMP). The branched [4]pseudorotaxane= assemblies {(DMP)3∙L}3+,where L = N-alkylated derivatives of the host molecule (±)-tris-(isonicotinoyl)cyclotriguaiacylene, were characterised by NMR spectroscopy and mass spectrometry, and an energy-minimised structure of {(DMP)3∙(tris-(N-propyl-isonicotinoyl)cyclotriguaiacylene)}3+ was calculated. Crystal structures of N-ethyl-isonicotinoyl)cyclotriguaiacylene hexafluorophosphate and N-propyl-isonicotinoyl)cyclotriguaiacylene hexafluorophosphate each show ‘hand-shake’ self-inclusion motifs occurring between the individual cavitands
Extreme call amplitude from near-field acoustic wave coupling in the stridulating water insect Micronecta scholtzi (Micronectinae)
Underwater acoustic transducers, particularly at low frequencies, are beset by problems of scale and inefficiency due to the large wavelengths of sound in water. In insect mating calls, a high call volume is usually desirable, increasing the range of signal transmission and providing a form of advertisement of the signaller's quality to a potential mate; however, the strength of the call is constrained by body size and by the need to avoid predators who may be listening in. Male crickets and water boatmen avoid some of the limitations of body size by exploiting resonant structures, which produce sharply tuned species specific songs, but call frequency and volume remain linked to body size. Recently, the water boatman Micronecta scholtzi was found to circumvent this rule, producing a louder mating call than that of similar, but much larger, Corixa. The resonant structure in Corixidae and Micronectinae is believed to be the trapped air reserves around the insect as it dives, driven by a stridulatory apparatus. However, the method by which energy is transferred from the striated area to the bubble is unknown. Here, we present modelling of a system of near-field coupling of acoustic sources to bubbles showing an exponential increase in sound power gain with decreasing distance that provides a simple solution to the stimulus of the air bubbles in Corixidae and Micronectinae and explains the discrepancy of M. scholtzi's extreme call volume. The findings suggest a possible route to engineered systems using near-field coupling to overcome size constraints in low-frequency (less than 500 Hz) underwater transducers, where the input efficiency of a piezoelectric device can be coupled through the hydrodynamic field to the high radiative efficiency of a near-ideal monopole emitter
A semi-classical over-barrier model for charge exchange between highly charged ions and one-optical electron atoms
Absolute total cross sections for electron capture between slow, highly
charged ions and alkali targets have been recently measured. It is found that
these cross sections follow a scaling law with the projectile charge which is
different from the one previously proposed basing on a classical over-barrier
model (OBM) and verified using rare gases and molecules as targets. In this
paper we develop a "semi-classical" (i.e. including some quantal features) OBM
attempting to recover experimental results. The method is then applied to
ion-hydrogen collisions and compared with the result of a sophisticated
quantum-mechanical calculation. In the former case the accordance is very good,
while in the latter one no so satisfactory results are found. A qualitative
explanation for the discrepancies is attempted.Comment: RevTeX, uses epsf; 6 pages text + 3 EPS figures Journal of Physics B
(scehduled March 2000). This revision corrects fig.
Super-resolution in map-making based on a physical instrument model and regularized inversion. Application to SPIRE/Herschel
We investigate super-resolution methods for image reconstruction from data
provided by a family of scanning instruments like the Herschel observatory. To
do this, we constructed a model of the instrument that faithfully reflects the
physical reality, accurately taking the acquisition process into account to
explain the data in a reliable manner. The inversion, ie the image
reconstruction process, is based on a linear approach resulting from a
quadratic regularized criterion and numerical optimization tools. The
application concerns the reconstruction of maps for the SPIRE instrument of the
Herschel observatory. The numerical evaluation uses simulated and real data to
compare the standard tool (coaddition) and the proposed method. The inversion
approach is capable to restore spatial frequencies over a bandwidth four times
that possible with coaddition and thus to correctly show details invisible on
standard maps. The approach is also applied to real data with significant
improvement in spatial resolution.Comment: Astronomy & Astrophysic
Smash products for secondary homotopy groups
We construct a smash product operation on secondary homotopy groups yielding
the structure of a lax symmetric monoidal functor. Applications on cup-one
products, Toda brackets and Whitehead products are considered. In particular we
prove a formula for the crossed effect of the cup-one product operation on
unstable homotopy groups of spheres which was claimed by
Barratt-Jones-Mahowald.Comment: We give a clearer description of the tensor product of symmetric
sequences of quadratic pair module
Spin Correlation Coefficients in pp-->pnpi+ from 325 to 400 MeV
The spin correlation coefficient combinations Axx + Ayy, Axx - Ayy and the
analyzing powers Ay(theta) were measured for pp-->pnpi+ at beam energies of
325, 350, 375 and 400 MeV. A polarized internal atomic hydrogen target and a
stored, polarized proton beam were used. These polarization observables are
sensitive to contributions of higher partial waves. A comparison with recent
theoretical calculations is provided.Comment: 8 Pages, 1 Table, 5 Figures. Accepted for publication in Phys. Lett.
- …