894 research outputs found
Urban Goods Movement and Local Climate Action Plans: Assessing Strategies to Reduce Greenhouse Gas Emissions from Urban Freight Transportation
This report examines how freight transport/goods movement has been addressed in U.S. city climate action planning. Transportation generally is a major contributor of greenhouse gas (GHG) emissions, and freight transport represents a growing component of transportationās share. Almost all climate action plans (CAPs) address transportation generally, but we wished to focus on efforts to reduce GHG emissions from freight transport specifically. We analyzed 27 advanced local CAPs to determine the degree to which freight transport was targeted in goals and strategies to reduce GHG emissions. We found only six CAPs that included direct measures or programs to reduce freight emissions. Many of the CAPs mentioned general transportation objectives such as lowering vehicle miles traveled or reducing emissions from city-owned vehicle fleets, but most did not include strategies or actions that explicitly targeted freight transport. We identified the specific strategies and actions that cities are taking to address GHG emissions from freight transport, such as working with the freight community to promote anti-idling and encourage transitions to electric and alternative fuel delivery vehicles. We also analyzed freight transport plans relevant for the same cities, and found that most do not explicitly mention reducing GHG emissions. Most of the freight plans are focused on improving reliability and efficiency of freight movement, which would likely have the ancillary benefit of reducing GHG emissions, but that goal was not explicitly targeted in most of these plans. Based on our findings, we recommend that cities specifically target freight transport goals and strategies in their CAPs and better coordinate with planners developing freight transport plans to identify GHG emission reduction approaches
A Comparison of AVIRIS and Landsat for Land Use Classification at the Urban Fringe
In this study we tested whether AVIRIS data allowed for improved land use classification over synthetic Landsat ETM+ data for a location on the urban-rural fringe of Colorado. After processing the AVIRIS image and creating a synthetic Landsat image, we used standard classification and post-classification procedures to compare the data sources for land use mapping. We found that, for this location, AVIRIS holds modest, but real, advantages over Landsat for the classification of heterogeneous and vegetated land uses. Furthermore, this advantage comes almost entirely from the large number of sensor spectral bands rather than the high Signal-to-Noise Ratio (SNR)
High Temperature Expansion for Frustrated and Unfrustrated S=1/2 Spin Chains
A computer aided high temperature expansion of the magnetic susceptibility
and the magnetic specific heat is presented and demonstrated for frustrated and
unfrustrated spin chains. The results are analytic in nature since the
calculations are performed in the integer domain. They are provided in the form
of polynomials allowing quick and easy fits. Various representations of the
results are discussed. Combining high temperature expansion coefficients and
dispersion data yields very good agreement already in low order of the
expansion which makes this approach very promising for the application to other
problems, for instance in higher dimensions.Comment: 13 pages, 8 figures, to appear in Eur. Phys. J. B, minor corrections,
correction of a[5] in table A.1.a, discussion of the region of validity
added, coefficients available electronically: http://www.thp.uni-koeln.de/~g
Mineralogy and composition of Archean Crust, Greenland: A pilot study
The Portable Instant Display and Analysis Spectrometer (PIDAS) was taken to southwestern Greenland to investigate in situ the potential application of AVIRIS to estimate the mineralogy and composition of rocks exposed in Archean terranes. The goal was to determine the feasibility of using a high spectral resolution scanner to find and study pristine rocks, those that have not been altered by subsequent deformation and metamorphism. The application of AVIRIS data to the problems in Greenland is logical. However, before a costly deployment of the U-2 aircraft to Greenland is proposed, this study was undertaken to acquire the spectral data necessary to verify that mineralogical mapping in the environmental conditions found there is possible. Although field conditions were far from favorable, all of the major objectives of the study were addressed. One of the major concerns was that lichens would obscure the rock surfaces. It was found that the spectral signature of the lichens was distinct from the underlying rocks. Thus, a spectrum of a rock outcrop, with its partial cover of lichens, can be un-mixed into rock and lichen components. The data acquired during the course of this study supports the conclusion that areas of pristine Archean crust can be differentiated from that which has experienced low grade alteration associated with Proterizoic faulting
Cross Correlators and Galilean Invariance in Fluctuating Ideal Gas Lattice Boltzmann Simulations
We analyze the Lattice Boltzmann method for the simulation of fluctuating
hydrodynamics by Adhikari et al. [Europhys. Lett. 71, 473 (2005)] and find that
it shows excellent agreement with theory even for small wavelengths as long as
a stationary system is considered. This is in contrast to other finite
difference and older lattice Boltzmann implementations that show convergence
only in the limit of large wavelengths. In particular cross correlators vanish
to less than 0.5%. For larger mean velocities, however, Galilean invariance
violations manifest themselves through errors of a magnitude similar to those
of the earlier implementations.Comment: 8 pages, 9 figures, DSFD 200
Density and conductivity of bismuth single crystals grown in magnetic fields with relation to their mosaic structure
In continuation of the study of the thermoelectric effect, previously described by Goetz and Hasler, existing between the two halves of the same bismuth single crystal, of which one has been crystallized within, and the other outside of a strong magnetic field (21,000 gauss), the density and the specific resistance of different sections of these crystals, grown by the discontinuous method, have now been measured.
The change of density of "magnetic" crystals. The density of perfect crystals grown under normal conditions was found to be between 9.82 and 9.83 i.e., 0.2 percent higher than the values of other authors. Furthermore, it was found that any crystalline imperfection such as twinning, etc., decreases the density; that, further there exists a difference of density between the "normal" and the "magnetic" half of the same crystal, the sign of which depends on the orientation with which the crystal entered the field: In case the trigonal axis is normal to the axis of the rod and normal to the lines of force, the "magnetic" half shows an increase of density, whereas the opposite is true in case the principal axis is parallel to the rod (and therefore parallel to the direction of growth and to the heat-flow). The difference of density is ca. 0.3 percent but can be several percent in imperfect crystals. The purity of the metal affects the change of the density. The results indicate that the ideally pure metal would not be affected by the magnetic treatment.
The specific resistance of "magnetic" crystals. The values of the specific resistance obtained on "normal" single crystals agree approximately with the results obtained by Bridgman and Kapitza and also with those obtained by spectroscopic analysis. The value of Ļā„/Ļā„ was found to be much larger for bismuth, being sensitive to the "magnetic" treatment. There is a small change of resistance between the normal and the magnetic half, depending on the orientation of the crystal to the field. In case the orientation is such as to decrease the density the resistance increases and vice versa. The accuracy necessary for the satisfactory quantitative determination of the change could not yet be reached, since the change is of the magnitude of 0.5 percent.
An attempt is made to combine the phenomena of the magnetic effect thus far known. It seems probable that the influence of the magnetic field upon the formation of a crystal consists of a change within the mosaic structure of the lattice. The investigation is being continued
The Portable Instant Display and Analysis Spectrometer (PIDAS)
A field spectrometer covering the range 0.4 to 2.5 microns was developed that acquires spectra in 2 seconds at 872 points within the spectrum. The Portable Instant Display and Analysis Spectrometer (PIDAS) can acquire spectra every 8 seconds and stores up to 288 spectra in bubble memory. A hand held display unit allows for display of the current spectrum acquired and superimposed on one of 128 permanently stored library spectra. PIDAS represents a major advance in the technology of field spectral data acquisition and for the first time makes possible the acquisition of enough spectra to characterize the mean and intraclass variance within a LANDSAT MSS or TM pixel
Hamiltonian mappings and circle packing phase spaces: numerical investigations
In a previous paper we introduced examples of Hamiltonian mappings with phase
space structures resembling circle packings. We now concentrate on one
particular mapping and present numerical evidence which supports the conjecture
that the set of circular resonance islands is dense in phase space.Comment: 9 pages, 2 figure
Method and apparatus for instantaneous band ratioing in a reflectance radiometer
A hand-held instrument is provided to compare information from selected infrared and visible bands in the 0.4 to 2.5 micrometer range, to perform ratioing via a dividing circuit (17) and to directly read out, via a display system (18), ratio values in a continuous digital display. The dual-beam, ratioing radiometer contains two optical trains (10, 12), each having two repeater lenses (L1a, L1b and L2a, L2b) and a cooled lead sulfide detector (D1, D2). One of the trains (10) is pivotal to facilitate measurements at distances ranging from about 1 meter to infinity. The optical trains are intersected by a set of two coaxially-mounted filter wheels (F1, F2), each containing up to five interference filters and slits to pass radiation filtered by the other. Filters with band passes as narrow as 0.01 micrometer are used in the region 0.4 to 2.5 micrometers. The total time for a calibration and measurement is only a few seconds. It is known from previous field studies using prior art devices, that materials, e.g., clay minerals, and carbonate minerals such as limestone, have unique spectral properties in the 2.0 to 2.5 micrometer region. Using properly chosen spectral filters, and ratioing the signals to remove the effect of topography on the brightness measured, the instrument can be used for real-time analysis of reflecting materials in the field. Other materials in the broader range of 0.4 to 2.5 micrometers (and even beyond) could be similarly identified once the reflectance spectrum of the material is established by any means
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