Land Use-Transportation Interaction: Lessons Learned from an Experimental Model using Cellular Automata and Artificial Neural Networks

Land use and transportation interact to produce large urban concentrations in most major cities that create tremendous sprawl, noise, congestion, and environmental concerns. The desire to better understand this relationship has led to the development of land use–transport (LUT) models as an extension of more general urban models. The difficulties encountered in developing such models are many as local actions sum to form global patterns of land use change, producing complex interrelationships. Cellular automata (CA) simplify LUT model structure, promise resolution improvement, and effectively handle the dynamics of emergent growth. Artificial Neural Networks (ANN) can be used to quantify the complex relationships present in historical land use data as a means of calibrating a CA-LUT model. This study uses an ANN, slope, historical land use, and road data to calibrate a CA-LUT model for the I-140 corridor of Knoxville, TN. The resulting model was found to require a complex ANN, produce realistic emergent growth patterns, and shows promising simulation performance in several significant land classes such as single-family residential. Problems were encountered as the model was iterated due to the lack of a mechanism to extend the road network. The presence of local roads in the model’s configuration strengthened ability of the model to simulate historical development patterns. Shortcomings in certain aspects of the simulation performance point to the need for the addition of a socio-economic sub-model to assess demand for urban area and/or an equilibrium mechanism to arbitrate the supply of developable land. The model constructed in this study was found to hold considerable potential for local-scale simulation and scenario testing given suitable modification to its structure and input parameters

Motivations and experiences of UK students studying abroad

This report summarises the findings of research aimed at improving understanding of the motivations behind the international diploma mobility of UK student

Black Holes at the IceCube Neutrino Telescope

If the fundamental Planck scale is about a TeV and the cosmic neutrino flux is at the Waxman-Bahcall level, quantum black holes are created daily in the Antarctic ice-cap. We re-examine the prospects for observing such black holes with the IceCube neutrino-detection experiment. To this end, we first revise the black hole production rate by incorporating the effects of inelasticty, i.e., the energy radiated in gravitational waves by the multipole moments of the incoming shock waves. After that we study in detail the process of Hawking evaporation accounting for the black hole's large momentum in the lab system. We derive the energy spectrum of the Planckian cloud which is swept forward with a large, O (10^6), Lorentz factor. (It is noteworthy that the boosted thermal spectrum is also relevant for the study of near-extremal supersymmetric black holes, which could be copiously produced at the LHC.) In the semiclassical regime, we estimate the average energy of the boosted particles to be less than 20% the energy of the neutrino-progenitor. Armed with such a constraint, we determine the discovery reach of IceCube by tagging on "soft" (relative to what one would expect from charged current standard model processes) muons escaping the electromagnetic shower bubble produced by the black hole's light descendants. The statistically significant 5-sigma excess extends up to a quantum gravity scale ~ 1.3 TeV.Comment: Matching version to be published in Phys. Rev.

From AMANDA to IceCube

The first string of the neoteric high energy neutrino telescope IceCube successfully began operating in January 2005. It is anticipated that upon completion the new detector will vastly increase the sensitivity and extend the reach of AMANDA to higher energies. A discussion of the IceCube's discovery potential for extra-terrestrial neutrinos, together with the prospects of new physics derived from the ongoing AMANDA research will be the focus of this paper. Preliminary results of the first antarctic high energy neutrino telescope AMANDA searching in the muon neutrino channel for localized and diffuse excess of extra-terrestrial neutrinos will be reviewed using data collected between 2000 and 2003. Neutrino flux limits obtained with the all-flavor dedicated UHE and cascade analyses will be described. A first neutrino spectrum above one TeV in agreement with atmospheric neutrino flux expectations and no extra-terrestrial contribution will be presented, followed by a discussion of a limit for neutralino CDM candidates annihilating in the center of the Sun.Comment: 15 pages, 8 figures Invited talk contribution at 5th International Conference on Non-accelerator New Physics (NANP 05), Dubna, Russia, 20-25 Jun 200

The crystal structure of calcite III

The crystal structure of calcite III has been deduced from existing high pressure powder X-ray diffraction patterns, based on the assumption that it is a displacive modification of the calcite I structure. The structure is monoclinic with space group C2 and a Z of 6. There are two Ca and two C positions, and five O positions, and atom coordinates have been refined by distance-least-squares methods to give reasonable octahedral coordination for Ca and parallel, planar CO_3 groups. Unit cell parameters refined from a published powder diffraction pattern at 4.1 GPa are: a = 8.746(8)Å; b = 4.685(5)Å; c = 8.275(8)Å; and β= 94.4°. The structure has a calculated density of 2.949 Mg/m³ at 4.1 GPa which is less than that of aragonite at this pressure and consistent with early piston cylinder studies. This implies that calcite III is indeed a metastable intermediary between calcite I and aragonite

Temperatures of shock-induced shear instabilities and their relationship to fusion curves

New emission spectra for MgO and CaAl_2Si_2O_8 (glass) are observed from 430 to 820 nm. Taken with previous data, we suggest that transparent solids display three regimes of light emission upon shock compression to successively higher pressures: (1) characteristic radiation such as observed in MgO and previously in other minerals, (2) heterogeneous hot spot (greybody) radiation observed in CaAl_2Si_2O_8 and previously in all transparent solids undergoing shock-induced phase transformations, and (3) blackbody emission observed in the high pressure phase regime in NaCl, SiO_2, CaO, CaAl_2Si_2O_8, and Mg_2SiO_4. The onset of regime (2) may delineate the onset of shock-induced polymorphism whereas the onset of regime (3) delineates the Hugoniot pressure required to achieve local thermal equilibrium in the shocked solid. We also propose that the hot spot temperatures and corresponding shock pressures determined in regime (2) delineate points on the fusion curves of the high pressure phase

Flood forecasting for the Buffalo Bayou using CRWR-PrePro and HEC-HMS

Center for Water and the Environmen

Shock temperatures in silica glass: Implications for modes of shock-induced deformation, phase transformation, and melting with pressure

Gray body temperatures and emittances of silica glass under shock compression between 10 and 30 GPa are determined. Observed radiative temperatures are higher than computed continuum temperatures for shock-compressed silica glass; however, below ∼26 GPa observed emittances are <0.02. This suggests that fused quartz deforms heterogeneously in this shock pressure range as has been observed in other minerals. Between 10 and 16 GPa, radiative temperatures decrease from 4400 K to 3200 K, whereas above 16–30 GPa, gray body temperatures of ∼3000 K with low emittances are observed. The emittances increase with pressure from 0.02 to 0.9. The pressure range from 10 to 16 GPa coincides with the permanent densification region, while the 16–30 GPa range coincides with the inferred mixed phase region along the silica glass Hugoniot. The differing radiative behaviors may relate to these modes of deformation. Based upon earlier shock recovery experiments and a proposed model of heterogeneous deformation under shock compression, the temperatures associated with low emittances in the mixed phase region probably represent the melting temperature of the high-pressure phase, stishovite, which can be expected to crystallize from a melt in hot zones. Above 20 GPa the melting temperature of stishovite would therefore be 3000 K±200 K and almost independent of pressure to 30 GPa. The effects of pressure on melting relations for the system SiO_2–Mg_2SiO_4 are considered together with the proposed stishovite melting curve and suggested maximum solidus temperatures within the mantle of ∼2370 K at 12.5 GPa and ∼2530 K at 20.0 GPa. Using the proposed stishovite melting temperatures Tm and estimates of upper mantle temperatures T, the effective viscosity, which can be considered a function of the homologous temperature T/T_m, appears to remain nearly constant from 200 to 600 km depth in the Earth

Impact and collisional processes in the solar system

As impact cratered terrains have been successively recognized on certain planets and planetary satellites, it has become clear that impact processes are important to the understanding of the accretion and evolution of all solid planets. The noble gases in the normalized atmospheric inventories of the planets and the normalized gas content of meteorites are grossly similar, but demonstrate differences from each other which are not understood. In order to study shock devolatilization of the candidate carrier phases which are principally thought to be carbonaceous or hydrocarbons in planetesimals, experiments were conducted on noble gase implantation in various carbons: carbon black, activated charcoal, graphite, and carbon glass. These were candidate starting materials for impact devolatilization experiments. Initial experiments were conducted on vitreous amorphous carbon samples which were synthesized under vapor saturated conditions using argon as the pressurizing medium. An amino acid and surface analysis by laser ionization analyses were performed on three samples of shocked Murchison meteorite. A first study was completed in which a series of shock loading experiments on a porous limestone and on a non-porous gabbro in one and three dimensions were performed. Also a series of recovery experiments were conducted in which shocked molten basalt a 1700 C is encapsulated in molybdenum containers and shock recovered from up to 6 GPa pressures