Field theoretic calculation of the surface tension for a model electrolyte system

We carry out the calculation of the surface tension for a model electrolyte to first order in a cumulant expansion about a free field theory equivalent to the Debye-H\"uckel approximation. In contrast with previous calculations, the surface tension is calculated directly without recourse to integrating thermodynamic relations. The system considered is a monovalent electrolyte with a region at the interface, of width h, from which the ionic species are excluded. In the case where the external dielectric constant epsilon_0 is smaller than the electrolyte solution's dielectric constant epsilon we show that the calculation at this order can be fully regularized. In the case where h is taken to be zero the Onsager-Samaras limiting law for the excess surface tension of dilute electrolyte solutions is recovered, with corrections coming from a non-zero value of epsilon_0/epsilon.Comment: LaTeX, 14 pages, 3 figures, 1 tabl

Design and Evaluation of an Integrated Safeguards System: Principles

An integrated safeguards system is defined as a collection of safeguards activities in which system components are coordinated to meet safeguards objectives efficiently within constraints imposed by safeguards resources, facility operations, potential adversaries, and regulatory requirements. This paper describes principles for designing and evaluating an integrated safeguards system that consists of four parts: (1) a problem definition phase that specifies resources and constraints composing the problem boundary values; (2) a system analysis/synthesis phase that describes how to select and integrate safeguards activities for efficient attainment of system objectives; (3) a system evaluation/optimization phase that defines measures of safeguards performance and develops methods for evaluating them; and (4) a decision-making phase that develops principles for selecting admissible designs and preference-ordering designs. 6 references, 4 figures, 5 tables

Curvature-Induced Defect Unbinding in Toroidal Geometries

Toroidal templates such as vesicles with hexatic bond orientational order are discussed. The total energy including disclination charges is explicitly computed for hexatic order embedded in a toroidal geometry. Related results apply for tilt or nematic order on the torus in the one Frank constant approximation. Although there is no topological necessity for defects in the ground state, we find that excess disclination defects are nevertheless energetically favored for fat torii or moderate vesicle sizes. Some experimental consequences are discussed.Comment: 12 pages, 15 eps figure

Behavior of Metallic Inclusions in Uranium Dioxide

The mobility of micron-size powders of refractory and noble metals in UO{sub 2} was investigated under isothermal and temperature gradient conditions, The metal particles were initially placed between two polished surfaces of UO{sub 2} and any movement which occurred during high temperature annealing was determined microscopically. Tungsten and molybdenum particles 1 to 10 {micro}m in diameter were immobile in UO{sub 2} at 2500°C in a temperature gradient of 1400°C/cm. Ruthenium, however, dissolved into and spread through hypostoichiometric, polycrystalline urania and was found after isothermal annealing as the U-Ru intermetallic compound in the grain boundaries of the oxide. The mechanism does not involve bodily motion of the metal particles. Rather, ruthenium dissolves in the grain bmmdaries of the oxide, migrates as atoms via the same pathway, and reacts while migrating to form URu{sub 3}, This product grows as layers in the grain boundaries. Isothermal ruthenium spreading followed simple diffusion theory, and apparent solubilities and effective diffusivities were obtained from the data for the temperature nmge 2000 to 2300°C. In a temperature gradient, ruthenium moves to the hot zones of UO{sub 2}; the mechanism appears to be the same as found for isothermal spreading, but the extent of movement up the temperature gradient cannot be explained by simple diffusion theory, even with an appreciable Soret effect

Pion and proton showers in the CALICE scintillator-steel analogue hadron calorimeter

Showers produced by positive hadrons in the highly granular CALICE scintillator-steel analogue hadron calorimeter were studied. The experimental data were collected at CERN and FNAL for single particles with initial momenta from 10 to 80 GeV/c. The calorimeter response and resolution and spatial characteristics of shower development for proton- and pion-induced showers for test beam data and simulations using Geant4 version 9.6 are compared.Comment: 26 pages, 16 figures, JINST style, changes in the author list, typos corrected, new section added, figures regrouped. Accepted for publication in JINS

Synchronization modulation increases transepithelial potentials in MDCK monolayers through Na/K pumps

Peer reviewedPublisher PD

Continuous selections of multivalued mappings

This survey covers in our opinion the most important results in the theory of continuous selections of multivalued mappings (approximately) from 2002 through 2012. It extends and continues our previous such survey which appeared in Recent Progress in General Topology, II, which was published in 2002. In comparison, our present survey considers more restricted and specific areas of mathematics. Note that we do not consider the theory of selectors (i.e. continuous choices of elements from subsets of topological spaces) since this topics is covered by another survey in this volume

Performance of the first prototype of the CALICE scintillator strip electromagnetic calorimeter

A first prototype of a scintillator strip-based electromagnetic calorimeter was built, consisting of 26 layers of tungsten absorber plates interleaved with planes of 45x10x3 mm3 plastic scintillator strips. Data were collected using a positron test beam at DESY with momenta between 1 and 6 GeV/c. The prototype's performance is presented in terms of the linearity and resolution of the energy measurement. These results represent an important milestone in the development of highly granular calorimeters using scintillator strip technology. This technology is being developed for a future linear collider experiment, aiming at the precise measurement of jet energies using particle flow techniques

The Time Structure of Hadronic Showers in highly granular Calorimeters with Tungsten and Steel Absorbers

The intrinsic time structure of hadronic showers influences the timing capability and the required integration time of hadronic calorimeters in particle physics experiments, and depends on the active medium and on the absorber of the calorimeter. With the CALICE T3B experiment, a setup of 15 small plastic scintillator tiles read out with Silicon Photomultipliers, the time structure of showers is measured on a statistical basis with high spatial and temporal resolution in sampling calorimeters with tungsten and steel absorbers. The results are compared to GEANT4 (version 9.4 patch 03) simulations with different hadronic physics models. These comparisons demonstrate the importance of using high precision treatment of low-energy neutrons for tungsten absorbers, while an overall good agreement between data and simulations for all considered models is observed for steel.Comment: 24 pages including author list, 9 figures, published in JINS

Shower development of particles with momenta from 15 GeV to 150 GeV in the CALICE scintillator-tungsten hadronic calorimeter

We present a study of showers initiated by electrons, pions, kaons, and protons with momenta from 15 GeV to 150 GeV in the highly granular CALICE scintillator-tungsten analogue hadronic calorimeter. The data were recorded at the CERN Super Proton Synchrotron in 2011. The analysis includes measurements of the calorimeter response to each particle type as well as measurements of the energy resolution and studies of the longitudinal and radial shower development for selected particles. The results are compared to Geant4 simulations (version 9.6.p02). In the study of the energy resolution we include previously published data with beam momenta from 1 GeV to 10 GeV recorded at the CERN Proton Synchrotron in 2010.Comment: 35 pages, 21 figures, 8 table