Geophysical models are increasingly recognized as an important component of regional calibrations for seismic monitoring. The models can be used to predict geophysical measurements, such as body wave travel times, and can be derived from direct regional studies or even by geophysical analogy. While empirical measurements of these geophysical parameters might be preferred, in aseismic regions or regions without seismic stations, this data might not exist. In these cases, models represent a 'best guess' of the seismic properties in a region, which improves on global models such as the PREM (Preliminary Reference Earth Model) or the IASPEI (International Association of Seismology and Physics of the Earth's Interior) models. The model-based predictions can also serve as a useful background for the empirical measurements by removing trends in the data. To this end, Lawrence Livermore National Laboratory (LLNL) has developed the WENA model for Western Eurasia and North Africa. This model is constructed using a regionalization of several dozen lithospheric (crust and uppermost mantle) models, combined with the Laske sediment model and 3SMAC upper mantle. We have evaluated this model using a number of data sets, including travel times, surface waves, receiver functions, and waveform analysis. Similarly, Los Alamos National Laboratory (LANL) …

Space debris constitutes a significant hazard to low earth orbit satellites and particularly to manned spacecraft. A quite small velocity decrease from vaporization impulses is enough to lower the perigee of the debris sufficiently for atmospheric drag to de-orbit the debris. A short pulse (picosecond) laser version of the Orion concept can accomplish this task in several years of operation. The ''Mercury'' short pulse Yb:S-FAP laser being developed at LLNL for laser fusion is appropriate for this task.

A novel method for determining the equation-of-state (EOS) along the release isentrope in an isochoric (constant volume) heated plasma is presented. The sensitivity of this approach is demonstrated using two different equation-of-state models for a solid density, 10 eV expanding Al plasma. Determining the material EOS data is validated to pressures near 80 Mbar, much higher than current isentropic compression experiments allow. Limitations at high temperature (T{sub e} {ge} 100 eV) due to the formation of a radiative conduction layer near the rarefaction interface are also illustrated.

Jets from radio galaxies can have dramatic effects on the medium through which they propagate. We review observational evidence for jet-induced star formation in low ('FR-I') and high ('FR-II') luminosity radio galaxies, at low and high redshifts respectively. We then discuss numerical simulations which are aimed to explain a jet-induced starburst ('Minkowski's Object') in the nearby FR-I type radio galaxy NGC 541. We conclude that jets can induce star formation in moderately dense (10 cm{sup -3}), warm (10{sup 4} K) gas; that this may be more common in the dense environments of forming, active galaxies; and that this may provide a mechanism for 'positive' feedback from AGN in the galaxy formation process.

One problem in similarity-based object retrieval (SBOR) is how to define and estimate the similarity between two objects. In this paper we present a shape similarity measure based on thin-plate splines, and compare its performance with several other measures used in SBOR. We evaluate the methods on both artificial and real images.

Irradiation embrittlement in nuclear reactor pressure vessel steels results from the formation of a high number density of nanometer sized copper rich precipitates and sub-nanometer defect-solute clusters. We present positron annihilation spectroscopy (PAS) results to characterize the compositions and magnetic character of these defects in model A533B reactor pressure vessel steels. The results confirm the presence of copper-rich precipitates after irradiation. The measured orbital electron momentum spectra indicate the precipitates are alloyed with Mn and Ni. The copper precipitates larger than R {approx} 1.2 nm (from SANS measurements) are non-magnetic, which limits the possible Fe content of the precipitates to at most a few %. Notably, large vacancy clusters observed in neutron irradiated Fe-Cu alloys were not observed in the steels after irradiation.

Current plans for Extreme Adaptive Optics systems place challenging requirements on wave-front control. This paper focuses on control system dynamics, wave-front sensing and wave-front correction device characteristics. It may be necessary to run an ExAO system after a slower, low-order AO system. Running two independent systems can result in very good temporal performance, provided specific design constraints are followed. The spatially-filtered wave-front sensor, which prevents aliasing and improves PSF sensitivity, is summarized. Different models of continuous and segmented deformable mirrors are studied. In a noise-free case, a piston-tip-tilt segmented MEMS device can achieve nearly equivalent performance to a continuous-sheet DM in compensating for a static phase aberration with use of spatial filtering.

Recent technical advances have made it possible to obtain very useful spectroscopic information about simple molecules at temperatures and pressures exceeding 2000K and 10 GPa inside a diamond-anvil cell, which is well above any melting point for such systems. This is accomplished by obtaining vibrational spectra via Coherent Anti-Stokes Raman Spectroscopy in conjunction with CW laser heating using a tungsten toroid as a laser target. By the simultaneous use of these techniques, vibrational spectra with relatively high signal to noise can be obtained despite the enormous thermal background generated by the incandescence of extremely hot laser heated material. Temperatures can be measured not only by fitting the Planck radiation to a graybody, but by the spectroscopic evidence of a Boltzmann distribution of molecules in their vibrationally excited quantum levels. Additionally, this technique allows for obtaining data at pressures and temperatures outside the region between the shock hugoniot and isentrope, complementing shock wave experiments.

We explore the validity of the generalized Bekenstein bound, S<= pi M a. We define the entropy S as the logarithm of the number of states which have energy eigenvalue below M and are localized to a flat space region of width alpha. If boundary conditions that localize field modes are imposed by fiat, then the bound encounters well-known difficulties with negative Casimir energy and large species number, as well as novel problems arising only in the generalized form. In realistic systems, however, finite-size effects contribute additional energy. We study two different models for estimating such contributions. Our analysis suggests that the bound is both valid and nontrivial if interactions are properly included, so that the entropy S counts the bound states of interacting fields.

The cardiovascular risk factor apolipoprotein(a) (apo(a)) has a puzzling distribution among mammals, its presence being limited to a subset of primates and a member of the insectivore lineage, the hedgehog. To explore the evolutionary history of apo(a), we performed extensive genomic sequence comparisons of multiple species with and without an apo(a) gene product, such as human, baboon, hedgehog, lemurand mouse. This analysis indicated that apo(a) arose independently in a subset of primates, including baboon and human, and an insectivore, the hedgehog, and was not simply lost by species lacking it. The similar structural domains shared by the hedgehog and primate apo(a) indicate that they were formed by a unique molecular mechanism involving the convergent evolution of paralogous genes in these distantspecies.

We study structural disorder produced in tetragonal KDP (KH{sub 2}PO{sub 4}) single crystals at room temperature by irradiation with MeV light ions. Results show that electronic energy loss plays a major role in the production of lattice defects in KDP. The effective diameters of ion tracks depend superlinearly on the electronic stopping power of energetic light ions. Structural lattice disorder is also accompanied by the formation of a network of cracks and blisters on the sample surface. Such irradiation-induced cracking and blistering typically evolves over extended periods of time (e.g., days) after bombardment, strongly affected by ion irradiation and sample storage conditions.

Alloy 22 (N06022) is the candidate material for the corrosion resistant, outer barrier of the nuclear waste container. Two of the potential corrosion degradation modes of the container are uniform corrosion and localized corrosion. A testing program at the Lawrence Livermore National Laboratory is being carried out for Yucca Mountain to determine the susceptibility of Alloy 22 to these two forms of corrosion using long-term immersion tests. Metallic coupons were exposed to several electrolyte solutions simulating concentrated ground water from pH 3 to 10 at 60 C and 90 C. This paper summarizes results on the characteristics of the surface deposits as well as the corrosion rate of 122 coupons of Alloy 22 obtained after more than a five-year exposure. The surface deposits consisted primarily of salt components in the respective solutions. Results showed little general corrosion and the absence of localized (crevice) corrosion.

A decision support system(DSS)is under development to assistin the control and management of episodes of dissolved oxygen sag in aDeep Water Ship Channel (DWSC), located in Stockton, California. The DWSCwas formed by excavating the bed of the San Joaquin River in the 1950'sto allow navigation by ocean-going cargo ships to the Port of Stockton.The deepened channel has the effect of increasing hydraulic residencetime by a factor of ten. allowing accumulation of decaying algae andother oxygen demanding substances - which creates a barrier to themigration of anadromous fish. This problem, which manifests itself inlate summer and early autumn, is an impediment to a multimillion dollarhabitat restoration effort for the salmon fishery in the San JoaquinRiver basin (SJRB). A hydrodynamic and water quality model of the Deltaand San Joaquin River forms the basis of the DSS which will provideforecasts of dissolved oxygen sag in the DWSC and provide modelingsupport for management actions such as forced aeration to improvedissolved oxygen concentrations in the Ship Channel. A graphical userinterlace, currently used for displaying flow and salinity forecasts onthe San Joaquin River, is being adapted to allow the display of dissolvedoxygen forecasts and to encourage the formation of a stakeholder-ledentity or institution to adaptively manage …

Immobilization of the high-level nuclear waste stored at the Hanford Reservation has been complicated by the presence of soluble, lower-valent technetium species. Previous work by Schroeder and Blanchard has shown that these species cannot be removed by ion-exchange and are difficult to oxidize. The Tc-K edge XANES spectra of the species in Tanks SY-101 and SY-103 were reported by Blanchard, but they could not be assigned to any known technetium complex. We report that the XANES spectra are most likely those of Tc(I) carbonyl species, especially fac-Tc(CO){sub 3}(gluconate){sup 2-}. This is further supported by EXAFS and {sup 99}Tc-NMR studies in nonradioactive simulants of these tank wastes.

LiFePO{sub 4}, Li{sub 0.98}Mg{sub 0.01}FePO{sub 4}, and Li{sub 0.96}Ti{sub 0.01}FePO{sub 4} were synthesized via a sol-gel method, using a variety of processing conditions. For comparison, LiFePO{sub 4} was also synthesized from iron acetate by a solid state method. The electrochemical performance of these materials in lithium cells was evaluated and correlated to mean primary particle size and residual carbon structure in the LiFePO{sub 4} samples, as determined by Raman microprobe spectroscopy. For materials with mean agglomerate sizes below 20 {micro}m, an association between structure and crystallinity of the residual carbon and improved utilization was observed. Addition of small amounts of organic compounds or polymers during processing results in carbon coatings with higher graphitization ratios and better electronic properties on the LiFePO{sub 4} samples and improves cell performance in some cases, even though total carbon contents remain very low (<2%). In contrast, no performance enhancement was seen for samples doped with Mg or Ti. These results suggest that it should be possible to design high power LiFePO{sub 4} electrodes without unduly compromising energy density by optimizing the carbon coating on the particles.

The long-term atmospheric corrosion performance of rolled zinc and three thermal-sprayed (TS) zinc materials (Zn, Zn-15Al, and Al-12Zn-0.2In) was characterized by measuring corrosion product concentrations in precipitation runoff at coastal marine and inland sites. Corrosion rates and average zinc concentrations in the runoff were greater at the site having higher annual rainfall. Higher chloride concentrations did not seem to affect either the corrosion rates or the zinc concentrations in the runoff at the coastal site compared to those of the inland site. Zinc runoff concentrations were higher for TS Zn than rolled zinc due to the greater surface area of the thermal-sprayed surface. Average cumulative zinc runoff losses for the two sites were: 64 {micro}mol Zn/L for TS Zn, 37 {micro}mol Zn/L for rolled Zn, 24 {micro}mol Zn/L for TS Zn-15Al, and 1.8 {micro}mol Zn/L for TS Al-12Zn-0.2In. Cumulative zinc runoff losses were directly related both to the precipitation rate and to the availability of Zn in metal surfaces, a consequence of surface roughness and surface chemistry properties of the metal.

Multiple scattering, modified fragmentation functions and radiative energy loss of a heavy quark propagating in a nuclear medium are investigated in perturbative QCD. Because of the quark mass dependence of the gluon formation time, the medium size dependence of heavy quark energy loss is found to change from a linear to a quadratic form when the initial energy and momentum scale are increased relative to the quark mass. The radiative energy loss is also significantly suppressed relative to a light quark due to the suppression of collinear gluon emission by a heavy quark.

Gas transmission pipelines are susceptible to both internal (gas side) and external (soil side) corrosion attack. Internal corrosion is caused by the presence of salt laden moisture, CO{sub 2}, H{sub 2}S, and perhaps O{sub 2} in the natural gas. Internal corrosion usually manifests itself as general corrosion. However, the presence of chlorides in entrained water also can lead to pitting corrosion damage. The electrochemical noise technique can differentiate general from localized corrosion and provide estimates of corrosion rates without external perturbation of the corroding system. It is increasingly being applied to field and industrial installations for in situ corrosion monitoring. It has been used here to determine its suitability for monitoring internal and external corrosion damage on gas transmission pipelines. Corrosion measurements were made in three types of environments: (1) aqueous solutions typical of those found within gas pipelines in equilibrium with th e corrosive components of natural gas; (2) biologically-active soils typical of wetlands; and (3) a simulated, unpressurized, internal gas/liquid gas pipeline environment. Multiple sensor designs were evaluated in the simulated pipe environment. Gravimetric measurements were conducted in parallel with the electrochemical noise measurements to validate the results.

Ash deposits cause accelerated corrosion of waterwall boiler tubes in waste to energy (WTE) incinerators. To study this effect, a series of experiments were planned to determine the mechanism of corrosion of carbon steel boiler tubes under ash deposits. Results reported here were for carbon steel tubes exposed to an environment consisting of O{sub 2}, CO{sub 2}, N{sub 2}, and water vapor. Future experiments will include HCl and SO{sub 2}. Test procedures included both isothermal and thermal gradient tests. Temperatures ranged from 300 C to 510 C for the isothermal tests and a metal/gas temperature of 450/670 C for the thermal gradient test. Initial results indicated that increasing temperature caused the isothermal corrosion rates of ash-covered samples to increase. A shakedown test of a thermal gradient test apparatus was conducted at a metal/gas temperature of 450/670 C, a more severe environment than normally encountered in WTE waterwalls. Results showed that the corrosion rate under those conditions exceeds the isothermal corrosion rates at the same metal temperature by a factor of 2 or more.

Identified mid-rapidity particle spectra of {pi}{sup {+-}}, K{sup {+-}}, and p({bar p}) from 200 GeV p+p and d+Au collisions are reported. A time-of-flight detector based on multi-gap resistive plate chamber technology is used for particle identification. The particle-species dependence of the Cronin effect is observed to be significantly smaller than that at lower energies. The ratio of the nuclear modification factor (R{sub dAu}) between (p+ {bar p}) and charged hadrons (h) in the transverse momentum range 1.2 < p{sub T} < 3.0 GeV/c is measured to be 1.19 {+-} 0.05(stat) {+-} 0.03(syst) in minimum-bias collisions and shows little centrality dependence. The yield ratio of (p + {bar p})/h in minimum-bias d+Au collisions is found to be a factor of 2 lower than that in Au+Au collisions, indicating that the Cronin effect alone is not enough to account for the relative baryon enhancement observed in heavy ion collisions at RHIC.

In the handling of tritium associated with heavy water moderator, there is a possibility that some of it, in the form of tritiated hydrogen or water vapor, may become airborne. An instrument is needed which will quantitatively measure tritium in air in order to protect personnel from the radiation hazard associated with tritium. This paper describes a portable air sampler developed to monitor concentrations of tritium in air between 4 x 10-5 and 1600 x 10-5 microcurie per cubic centimeter.

On October 08, 2001 a small felt earthquake occurred near Upper Three Runs Creek in the north central area of the Savannah River Site, South Carolina. Seven very small aftershocks followed the main event with the last one occurring March 06, 2002. All activity occurred within a small area. Further analysis of collected data indicates a correlation of this low level seismic activity with a small northwest trending structure observed in detailed gravity and magnetic data. Both single event and composite focal mechanisms were derived using local and regional stations. Results indicated predominantly dip-slip motion along a fault striking NNW at 335 degrees and dipping 41 degrees to the southwest. A 3D plot of the eight hypocenters clearly defines a fault plane nearly analogous to that obtained from the focal solutions. The Upper Three Runs series of events is another example of a separate class of earthquakes that occur within the central Piedmont and upper Coastal Plain of South Carolina. The Upper Three Runs sequence of events demonstrates that shallow intersections of structures interpreted from potential field data can be the foci for localized stress concentrations where microearthquake activity can occur. These earthquakes are attributable to small scale faults associated …

Traffic flow on a unidirectional roadway in the presence of traffic lights is modeled. Individual car responses to green, yellow, and red lights are postulated and these result in rules governing the acceleration and deceleration of individual cars. The essence of the model is that only specific cars are directly affected by the lights. The other cars behave according to simple follow-the-leader rules which limit their speed by the spacing between it and the car directly ahead. The model has a number of desirable properties; namely cars do not run red lights, cars do not smash into one another, and cars exhibit no velocity reversals. In a situation with multiple lights operating in-phase we get, after an initial startup period, a constant number of cars through each light during any green-yellow period. Moreover, this flux is less by one or two cars per period than the flux obtained in discretized versions of the idealized Lighthill, Whitham, Richards model which allows for infinite accelerations.

In this paper we focus on melting and solidification processes described by phase-field models and obtain rigorous estimates for such processes. These estimates are derived in Section 2 and guarantee the convergence of solutions to non-constant equilibrium patterns. The most basic results conclude with the inequality (2.31). The estimates in the remainder of Section 2 illustrate what obtains if the initial data is progressively more regular and may be omitted on first reading. We also present some interesting numerical simulations which demonstrate the equilibrium structures and the approach of the system to non-constant equilibrium patterns. The novel feature of these calculations is the linking of the small parameter in the system, {delta}, to the grid spacing, thereby producing solutions with approximate sharp interfaces. Similar ideas have been used by Caginalp and Sokolovsky [1]. A movie of these simulations may be found at http:www.math.cmu.edu/math/people/greenberg.html.