cssi/SciSciGPT-SciSciNet huggingface dataset:
Fuel Cell ASAP: Two Iterations of an Automated Stack Assembly Process and Ramifications for Fuel Cell Design-for-Manufacture Considerations

Polymer-electrode membrane (PEM) fuel cell technology, a low-emissions power source receiving much attention for its efficiency, will need to progress from low-volume production to high-volume within the course of the next decade. To successfully achieve this transition, significant research progress has already been made towards developing a fully-functional fuel cell automatic stack assembly robotic station. Lessons can be drawn from this research with regards to design-for-manufacture (DFM) and design-for-assembly (DFA) considerations of fuel cells; however, more work still remains to be done. This document outlines both iterations of the robotic fuel cell assembly stations, other work to date, DFM and DFA lessons learned, and the anticipated future progression of automatic fuel cell stack assembly stations. A literature search reveals numerous patents pertaining to equipment and processes for fuel cell assembly as well as a great number of patents pertaining to fuel cell stack features to aid in manufacture or assembly. However, most of this is focused upon proper compression of the membrane material, with little thought given to overall assembly and throughput. Journal articles have begun to consider real-world manufacturing considerations pertinent to production scale-up, but much remains to be done. Therefore, there is a need for more contributions to stack manufacture and assembly. Work already completed (by the authors and their lab) towards the manufacturing workcell specifically includes the design and construction of two individual robotic fuel cell assembly stations, including custom-built end effectors and parts feeders. The second station incorporated numerous improvements, including overlapping work envelopes, elimination of a shuttle cart, software synchronization, fewer axes, and a better end effector. Consequentially, the second workcell achieved a four-fold improvement in cycle time over the previous iteration. Future improvements will focus in part upon improving the reliability of the overall system. Close study of the manufacturing workcell indicated that stack component design features are key for production and scale-up of fuel cell stack manufacturing processes. Critical features are discussed in this article, as well as their ramifications for the overall stack design. As the stack assembly workcell continues to improve, research will focus upon the ramifications and interplay of tolerances, stack failure modes, sealing, reliability, and the potential for component redesign specifically to optimize fuel cell manufacturing throughput.Copyright © 2009 by ASME
Discovery of an X-Ray Nova in M31

We have obtained snapshot images of an X-ray nova in M31 from Chandra ACIS-I and the Hubble Space Telescope (HST) Advanced Camera for Surveys. The Chandra position of the X-ray nova was R.A. = 00h44m0668 ± 174, decl. = +41°12'200 ± 231 (J2000.0). A follow-up HST observation 24 days later revealed a source at R.A. = 00h44m0681, decl. = +41°12'240 that was B = 25.75 ± 0.05. This optical source faded to B = 27.1 ± 0.1 in 3 months. During this time period, the X-ray flux decayed linearly from (3.6 ± 0.2) × 10-4 to <(6.9 ± 0.09) × 10-5 counts cm-2 s-1. The HST identification of an optical source in the same region experiencing an obvious drop in brightness in concert with the X-ray nova suggests that this optical source is the counterpart of the X-ray nova. However, the precision of the X-ray position allows the possibility that the optical source is a nearby variable star. We discuss the implications of both possibilities.
New Lower Bounds for Statistical Query Learning

We prove two lower bounds in the statistical query (SQ) learning model. The first lower bound is on weak-learning. We prove that for a concept class of SQ-dimension d, a running time of @W(d/logd) is needed. The SQ-dimension of a concept class is defined to be the maximum number of concepts that are ''uniformly correlated'', in that each of their pair has nearly the same correlation. This lower bound matches the upper bound in Blum et al. (Weakly Learning DNF and Characterizing Statistical Query Learning using Fourier Analysis, STOC 1994, pp. 253-262), up to a logarithmic factor. We prove this lower bound against an ''honest SQ-oracle'', which gives a stronger result than the ones against the more frequently used ''adversarial SQ-oracles''. The second lower bound is more general. It gives a continuous trade-off between the ''advantage'' of an algorithm in learning the target function and the number of queries it needs to make, where the advantage of an algorithm is the probability it succeeds in predicting a label minus the probability it does not. Both lower bounds extend and/or strengthen previous results, and solve an open problem left in previous papers. An earlier version of this paper [K. Yang, New lower bounds for statistical query learning, in: The Proceedings of the 15th Annual Conference on Computational Learning Theory, COLT 2002, Sydney, Australia, July 8-10, Lecture Notes in Computer Science, vol. 2375, 2002, pp. 229-243.] appeared in the proceedings of the 15th Annual Conference on Computational Learning Theory (COLT 2002).
Tax reforms and the growth of government

This paper analyzes alternative approaches to measuring the effects of structural tax changes on government growth. It first reviews traditional time series approaches that attempt to disentangle the causal relationships between taxes and spending. It explains why these methods are incapable of uncovering the true causal links because of problems of observational equivalence and why institutional data can assist in making this determination. It then presents the methods and results from two alternative approaches and studies that analyze the effects of changes in tax structures on government growth. Both methods rely on econometric and institutional analysis.
Compact Weighted Composition Operators and Fixed Points in Convex Domains

Let be a bounded, convex domain in , and suppose that is holomorphic. Assume that is analytic, bounded away from zero toward the boundary of , and not identically zero on the fixed point set of . Suppose also that the weighted composition operator given by is compact on a holomorphic, functional Hilbert space (containing the polynomial functions densely) on with reproducing kernel satisfying as . We extend the results of J. Caughran/H. Schwartz for unweighted composition operators on the Hardy space of the unit disk and B. MacCluer on the ball by showing that has a unique fixed point in . We apply this result by making a reasonable conjecture about the spectrum of based on previous results.
Random number generators are chaotic

The study of highly unstable nonlinear dynamical systems—chaotic systems—has emerged recently as an area of major interest and applicability across the mathematical, physical and social sciences. This interest has been triggered by advances in the past decade, particularly in the mathematical understanding of complex systems. An important insight that has become widely recognized in recent years is that deterministic systems can give rise to chaotic behavior. Surprisingly, many of these systems are extremely simple, yet they exhibit complex chaotic behavior.
Evaluating stationarity via change-point alternatives with applications to fMRI data

Functionalmagnetic resonance imaging (fMRI) is now a well-established technique for studying the brain. However, in many situations, such as when data are acquired in a resting state, it is difficult to know whether the data are truly stationary or if level shifts have occurred. To this end, change-point detection in sequences of functional data is examined where the functional observations are dependent and where the distributions of change-points from multiple subjects are required. Of particular interest is the case where the change-point is an epidemic change-a change occurs and then the observations return to baseline at a later time. The case where the covariance can be decomposed as a tensor product is considered with particular attention to the power analysis for detection. This is of interest in the application to fMRI, where the estimation of a full covariance structure for the three-dimensional image is not computationally feasible. Using the developed methods, a large study of resting state fMRI data is conducted to determine whether the subjects undertaking the resting scan have nonstationarities present in their time courses. It is found that a sizeable proportion of the subjects studied are not stationary. The change-point distribution for those subjects is empirically determined, as well as its theoretical properties examined.
Heterotic compactifications with principal bundles for general groups and general levels

We examine to what extent heterotic string worldsheets can describe arbitrary E8 ×E8 gauge fields. The traditional construction of heterotic strings builds each E8 via a Spin(16)/Z2 subgroup, typically realized as a current algebra by left-moving fermions, and as a result, only E8 gauge fields reducible to Spin(16)/Z2 gauge fields are directly realizable in standard constructions. However, there exist perturbatively consistent E8 gauge fields which can not be reduced to Spin(16)/Z2, and so cannot be described within standard heterotic worldsheet constructions. A natural question to then ask is whether there exists any (0,2) SCFT that can describe such E8 gauge fields. To answer this question, we first show how each tendimensional E8 partition function can be built up using other subgroups than Spin(16)/Z2, then construct “fibered WZW models” which allow us to explicitly couple current algebras for general groups and general levels to heterotic strings. This technology gives us a very general approach to handling heterotic compactifications with arbitrary principal bundles. It also gives us a physical realization of some elliptic genera constructed recently by Ando and Liu.
Heavy Quark Spectroscopy - Theory Overview

Some recent discoveries in the spectroscopy of hadrons containing heavy quarks, and some of their theoretical interpretations, are reviewed.
Regularity of smooth curves in biprojective spaces

Abstract Maclagan and Smith [D. Maclagan, G.G. Smith, Multigraded Castelnuovo–Mumford regularity, J. Reine Angew. Math. 571 (2004) 179–212] developed a multigraded version of Castelnuovo–Mumford regularity. Based on their definition we will prove in this paper that for a smooth curve C ⊆ P a × P b ( a , b ⩾ 2 ) of bidegree ( d 1 , d 2 ) with nondegenerate birational projections the ideal sheaf I C | P a × P b is ( d 2 − b + 1 , d 1 − a + 1 ) -regular. We also give an example showing that in some cases this bound is the best possible.
One-, two-, and three-channel Kondo effects for a model Ce 3 + impurity in a metal

We present studies of a simple Anderson model Hamiltonian for Ce{sup 3+} ions in cubic symmetry with three configurations (f{sup 0},f{sup 1},f{sup 2}). In different parameter regimes, our model Hamiltonian maps to the one-, two-, and three-channel spin-1/2 Kondo models. Using third-order scaling (perturbative renormalization group) analysis, we study the stability of the non-Fermi-liquid fixed point of the two-channel Kondo model for Ce{sup 3+} ions in cubic symmetry against the one-channel Kondo interaction. Using the noncrossing approximation (NCA), we also report detailed studies for our simplified model of the competition between the Fermi-liquid fixed point of the one-channel Kondo model and the non-Fermi fixed points of the two- and three-channel Kondo models. We provide the phase diagram in the model parameter space and study the thermodynamics and the transport properties of our simplified model Hamiltonian. Thermodynamics and transport coefficients show distinct behaviors for different numbers of channels. We confirm in detail that the NCA is a valid numerical method for the overcompensated multichannel S{sub I}=1/2 Anderson models. Our model study might be relevant to the non-Fermi-liquid alloy Ce{sub 1{minus}x}La{sub x}Cu{sub 2.2}Si{sub 2}. {copyright} {ital 1997} {ital The American Physical Society}
Off-Axis Cluster Mergers: Effects of a Strongly Peaked Dark Matter Profile

We present a parameter study of offset mergers between clusters of galaxies. Using the Eulerian hydrodynamics/N-body code COSMOS, we simulate mergers between nonisothermal, hydrostatic clusters with a steep central dark matter density profile and a β-model gas profile. We constrain global properties of the model clusters using observed cluster statistical relationships. We consider impact parameters between 0 and 5 times the dark matter scale radius and mass ratios of 1 : 1 and 1 : 3. The morphological changes, relative velocities, and temperature jumps we observe agree with previous studies using the King profile for the dark matter. We observe a larger jump in X-ray luminosity (~4-10 times) than in previous work, and we argue that this increase is most likely a lower limit due to our spatial resolution. We emphasize that luminosity and temperature jumps due to mergers may have an important bearing on constraints on Ω derived from the observation of hot clusters at high redshift. Shocks are relatively weak in the cluster cores; hence, they do not significantly increase the entropy there. Instead, shocks create entropy in the outer regions, and this high-entropy gas is mixed with the core gas during later stages of the merger. Ram pressure initiates mixing by displacing the core gas from its potential center, causing it to become convectively unstable. The resulting convective plumes produce large-scale turbulent motions with eddy sizes up to several hundred kiloparsecs. This turbulence is pumped by dark matter-driven oscillations in the gravitational potential. Even after nearly a Hubble time these motions persist as subsonic turbulence in the cluster cores, providing 5%-10% of the support against gravity. The dark matter oscillations are also reflected in the extremely long time following a merger required for the remnant to reach virial equilibrium.
Maxillary tumor of retinal anlage.

Abstract The clinical history is presented of a 6-month-old white girl who had a tumor removed from the maxilla. The neoplasm composed of tissue elements of the retina is believed to be the first tumor of retinal anlage ever recorded.
THE ORIGIN OF THE DUST ARCH IN THE HALO OF NGC 4631: AN EXPANDING SUPERBUBBLE?

We study the nature and the origin of the dust arch in the halo of the edge-on galaxy NGC 4631 detected by Neininger & Dumke. We present CO observations made using the new on-the-fly mapping mode with the Five College Radio Astronomy Observatory 14 m telescope and find no evidence for CO emission associated with the dust arch. Our examination of previously published H I data shows that, if previous assumptions about the dust temperature and gas/dust ratio are correct, then there must be molecular gas associated with the arch, below our detection threshold. If this is true, then the molecular mass associated with the dust arch is between 1.5 × 108 M⊙ and 9.7 × 108 M⊙, and likely toward the low end of the range. A consequence of this is that the maximum allowed value for the CO-to-H2 conversion factor is 6.5 times the Galactic value, but most likely closer to the Galactic value. The kinematics of the H I apparently associated with the dust arch reveals that the gas here is not part of an expanding shell or outflow but is instead two separate features (a tidal arm and a plume of H I sticking out into the halo) that are seen projected together and appear as a shell. Thus there is no connection between the dust "arch" and the hot X-ray–emitting gas that appears to surround the galaxy.
Shoulder Instability with Concomitant Bone Loss in the Athlete

Thorough evaluation of the athlete with persistent shoulder instability and appropriate use of imaging modalities, such as 3-dimensional computed tomography, can help quantify the severity of bony deficiency. Based on obtained imaging and examination, surgical and nonsurgical methods can be considered. In many situations both the humeral- and glenoid-sided bone loss must be addressed. Depending on the extent of bone loss, athletic demands, and surgeon experience, arthroscopic or open surgical options can provide shoulder stability and return athletes to their prior level of activity.
A Controlled Sensing Approach to Graph Classification

The problem of classifying graphs with respect to connectivity via partial observations of nodes is posed as a composite hypothesis testing problem with controlled sensing. An observation at a node is a subset of edges incident to the node on the complete graph drawn according to a probability model, which is a function of a fixed underlying graph. Connectivity is measured through average node degree and is classified with respect to a threshold. A simple approximation of the controlled sensing test is derived and simulated on Erdos-Renyi graphs to characterize the error probabilities as a function of the expected stopping times. The test is also experimentally validated on a real-world example of the social structure of Long-Tailed Manakins. It is shown that the proposed test achieves favorable tradeoffs between the classification error and the number of measurements. Furthermore, the test outperforms existing approaches, especially at low target error rates. In addition, the proposed test achieves the optimal error exponent.
Oxygen reduction catalysis of the Pt3Co alloy in alkaline and acidic media studied by X-ray photoelectron spectroscopy and electrochemical methods

The surface structure, stability, and electrocatalytic activity of the Pt3Co alloy toward oxygen reduction reaction (ORR) (with reference to Pt black) in both alkaline and acidic media were studied by X-ray photoelectron spectroscopy (XPS), cyclic voltammetry, and by the rotating disk electrode method. The XPS data show that two species of cobalt, metallic cobalt and cobalt oxides, coexist in the as-received Pt3Co sample. In combination with the voltammetric results, the XPS data demonstrate that there is dissolution of cobalt upon exposure of the sample to acidic media, whereas the cobalt forms in the catalyst are stable in alkaline media. In addition, the Pt 4f binding energy was found by XPS to be upshifted by 0.2 eV vs that of the pure Pt black reference. In acids, Pt3Co alloy has a slightly but demonstratively higher activity than Pt black toward the oxygen reduction reaction as shown by the positive half-wave potential shift of ca. 10 ± 2 mV, while in alkaline media a decrease in the ORR activity wa...
Adsorption-induced deformation of mesoporous solids.

The Derjaguin−Broekhoff−de Boer theory of capillary condensation is employed to describe deformation of mesoporous solids in the course of adsorption−desorption hysteretic cycles. We suggest a thermodynamic model, which relates the mechanical stress induced by the adsorbed phase to the adsorption isotherm. Analytical expressions are derived for the dependence of the solvation pressure on the vapor pressure. The proposed method provides a description of nonmonotonic hysteretic deformation during capillary condensation without invoking any adjustable parameters. The method is showcased drawing on the examples of literature experimental data on adsorption deformation of porous glass and SBA-15 silica.
The Integration of Energy Policy Models

Abstract In this paper we present an integrated model for the assessment of alternative U.S. energy policies, based on the Inter-Industry Model constructed by Hudson and Jorgenson and the Natural Gas Model constructed by MacAvoy and Pindyck. We first present the Inter-Industry Model and an outline of the computational techniques employed in implementing the model. We then describe the Natural Gas Model and the details of its implementation. We next present a methodology for integrating energy policy models. The methodology imposes certain consistency requirements on alternative models of the same phenomena. We apply this methodology to the incorporation of exploration and development and wellhead price regulation of natural gas into the integrated energy policy model. Finally, we present four policy simulations with the integrated model. These simulations are the four possible combinations of quotas on oil imports versus no quotas and phased deregulation of the price of natural gas versus no deregulation. Our simulation results support a policy of phased deregulation with no restrictions on oil imports.
An altitudinal comparison of water and metabolic relations in two acridid grasshoppers (Orthoptera)

Abstract 1. 1. Water loss rates (WLR) and oxygen consumption rates ( dot V O 2 ) were determined for two species of grasshoppers inhabiting hot, low elevation deserts to cool, high altitude meadows. 2. 2. Water loss rates and oxygen consumption rates were positively correlated with increasing elevation. 3. 3. Decreased WLR in desert animals and increased dot V O 2 , in high elevation animals are considered important adaptations to xeric conditions and short growing seasons respectively.
Object Color Preferences

In this article, we investigate how context influ- ences color preferences by comparing preferences for ''contextless'' colored squares with preferences for colors of a variety of objects (e.g., walls, couches, and T-shirts). In experiment 1, we find that hue preferences for context- less squares generalize relatively well to hue preferences for imagined objects, with the substantial differences being in the saturation and lightness dimensions. In experiments 2 and 3, we find that object color preferences are relatively invariant when the objects are (a) imagined to be the color that is presented as a small square, (b) depicted as colored images of objects, and (c) viewed as actual physical objects. In experiment 4, we investigate the possibility that object color preferences are related to the degree to which colors help objects fulfill particular functions or outcomes. We also discuss relations between our results and previous theories of color prefer- ence. 2012 Wiley Periodicals, Inc. Col Res Appl, 00, 000 - 000, 2012; Published online in Wiley Online Library (wileyonlinelibrary. com). DOI 10.1002/col.21756
Dowry deaths: Response to weather variability in India

Abstract We examine the effect of rainfall shocks on dowry deaths using data from 583 Indian districts for 2002–2007. We find that a one standard deviation decline in annual rainfall from the local mean increases reported dowry deaths by 7.8%. Wet shocks have no apparent effect. We examine patterns of other crimes to investigate whether an increase in general unrest during economic downturns explains the results but do not find supportive evidence. Women's political representation in the national parliament has no apparent mitigating effect on dowry deaths.
A FINITE-VOLUME-BASED TIME-SPLITTING SCHEME FOR COMPUTATION OF ELECTRODEPOSITION

The LIGA process is emerging as a viable contender in the microfabrication of metallic high-aspect-ratio microstructures. The final step in the LIGA process is the electroplating of the metal part. In this step, metallic ions are transported to the cathode by the fluid and are deposited on it through chemical reactions. There are two kinds of chemical reactions: homogeneous dissociation reactions in the electrolyte bath, and finite-rate surface reactions on the electrode. In this article we develop a finite-volume method for computing electrodeposition in the LIGA process. We employ a time-splitting algorithm for coupling the bulk and surface reactions. First there is an instantaneous equilibration step in which the species existing in a cell are equilibrated to yield an intermediate concentration distribution. This serves as the initial condition to the transport step in which slow reactions and convective and diffusive transport are computed. As an alternative, the species concentration field is solved ...
Analysis of Finite Difference Discretization Schemes for Diffusion in Spheres with Variable Diffusivity

Abstract Two finite difference discretization schemes for approximating the spatial derivatives in the diffusion equation in spherical coordinates with variable diffusivity are presented and analyzed. The numerical solutions obtained by the discretization schemes are compared for five cases of the functional form for the variable diffusivity: (I) constant diffusivity, (II) temporally dependent diffusivity, (III) spatially dependent diffusivity, (IV) concentration-dependent diffusivity, and (V) implicitly defined, temporally and spatially dependent diffusivity. Although the schemes have similar agreement to known analytical or semi-analytical solutions in the first four cases, in the fifth case for the variable diffusivity, one scheme produces a stable, physically reasonable solution, while the other diverges. We recommend the adoption of the more accurate and stable of these finite difference discretization schemes to numerically approximate the spatial derivatives of the diffusion equation in spherical coordinates for any functional form of variable diffusivity, especially cases where the diffusivity is a function of position.
Central dopaminergic neurons: Neurophysiological identification and responses to drugs

Publisher Summary This chapter describes the neurophysiological identification, and responses to drugs of central dopaminergic neurons. Neurons in the rat brain identified as dopaminergic were found to be remarkably homogeneous with respect to their firing pattern, and responses to drugs and other substances administered systemically, or applied iontophoretically. In these same respects, dopaminergic neurons were clearly distinguishable from neurons in nearby areas, such as the ZR of the substantia nigra, the red nucleus, or the reticular formation. Dopaminergic cells typically show extracellular action potentials with a positive-negative wave form of unusually long duration. They tend to have a regular rhythm and a slow rate of firing in unanesthetised, gallamine-paralyzed preparations, but curiously exhibit an increase in firing rate and a bursting pattern when the animal is anesthetized with chloral hydrate, or halothane. In contrast, ZR cells tend to have a relatively rapid rate of firing, and are either unaffected, or depressed by anesthesia.
Multicomponent Flow Calculations by a Consistent Primitive Algorithm

The dynamics of inviscid multicomponent fluids may be modelled by the Euler equations, augmented by one (or more) additional species equation(s). Attempts to compute solutions for extended Euler models in conservation form, show strong oscillations and other computational inaccuracies near material interfaces. These are due to erroneous pressure fluctuations generated by the conservative wave model. This problem does not occur in single component computations and arises only in the presence of several species. A nonconservative (primitive) Euler formulation is proposed, which results in complete elimination of the oscillations. The numerical algorithm uses small viscous perturbations to remove leading order conservation errors and is conservative to the order of numerical approximation. Numerical experiments show clean monotonic solution profiles, with acceptably small conservation error for shocks of weak to moderate strengths.
QUANTUM GROUPS AT ROOTS OF UNITY AND MODULARITY

We develop the basic representation theory of all quantum groups at all roots of unity (that is, for q any root of unity, where q is defined as in [18]), including Harish–Chandra's theorem, which allows us to show that an appropriate quotient of a subcategory gives a semisimple ribbon category. This work generalizes previous work on the foundations of representation theory of quantum groups at roots of unity which applied only to quantizations of the simplest groups, or to certain fractional levels, or only to the projective form of the group. The second half of this paper applies the representation theory to give a sequence of results crucial to applications in topology. In particular, for each compact, simple, simply-connected Lie group we show that at each integer level the quotient category is in fact modular (thus leading to a Topological Quantum Field Theory), we determine when at fractional levels the corresponding category is modular, and we give a quantum version of the Racah formula for the decomposition of the tensor product.
Integration of melody and text in memory for songs

Abstract Two experiments examined whether the memory representation for songs consists of independent or integrated components (melody and text). Subjects heard a serial presentation of excerpts from largely unfamiliar folksongs, followed by a recognition test. The test required subjects to recognize songs, melodies, or texts and consisted of five types of items: (a) exact songs heard in the presentation; (b) new songs; (c) old tunes with new words; (d) new tunes with old words; and (e) old tunes with old words of a different song from the same presentation (‘mismatch songs’). Experiment 1 supported the integration hypothesis: Subjects' recognition of components was higher in exact songs (a) than in songs with familiar but mismatched components (e). Melody recognition, in particular, was near chance unless the original words were present. Experiment 2 showed that this integration of melody and text occurred also across different performance renditions of a song and that it could not be eliminated by voluntary attention to the melody.
On the rapid decay of cuspidal automorphic forms

Abstract Many important analytic statements about automorphic forms, such as the analytic continuation of certain L -functions, rely on the well-known rapid decay of K -finite cusp forms on Siegel sets. We extend this here to prove a more general decay statement along sets much larger than Siegel sets, and furthermore state and prove the decay for smooth but not necessarily K -finite cusp forms. We also state a general theorem about the convergence of Rankin–Selberg integrals involving unipotent periods, closing a gap in the literature on L -functions. These properties serve as the analytic basis (Miller and Schmid, 2009 [15] ) of a new method to establish holomorphic continuations of Langlands L -functions, in particular the exterior square L -functions (Miller and Schmid, 2009 [16] ) on G L ( n ) .
Radio Sources Toward Galaxy Clusters at 30 GHz

Extra-galactic radio sources are a significant contaminant in cosmic microwave background and Sunyaev-Zeldovich effect experiments. Deep interferometric observations with the BIMA and OVRO arrays are used to characterize the spatial, spectral, and flux distributions of radio sources toward massive galaxy clusters at 28.5 GHz. We compute counts of mJy source fluxes from 89 fields centered on known massive galaxy clusters and 8 non-cluster fields. We find that source counts in the inner regions of the cluster fields (within 0.5 arcmin of the cluster center) are a factor of 8.9 (+4.2 to -3.8) times higher than counts in the outer regions of the cluster fields (radius greater than 0.5 arcmin). Counts in the outer regions of the cluster fields are in turn a factor of 3.3 (+4.1 -1.8) greater than those in the noncluster fields. Counts in the non-cluster fields are consistent with extrapolations from the results of other surveys. We compute spectral indices of mJy sources in cluster fields between 1.4 and 28.5 GHz and find a mean spectral index of al[ja = 0.66 with an rms dispersion of 0.36, where flux S varies as upsilon(sup -alpha). The distribution is skewed, with a median spectral index of 0.72 and 25th and 75th percentiles of 0.51 and 0.92, respectively. This is steeper than the spectral indices of stronger field sources measured by other surveys.
A vehicle health monitoring system evaluated experimentally on a passenger vehicle

A vehicle health monitoring system based on analytical redundancy, is developed for automated passenger vehicles. A residual generator and a residual processor are designed together to detect and identify actuator and sensor faults of the Buick LeSabre rapidly. The residual generator includes fault detection filters and parity equations. It uses the control commands and sensor measurements to generate the residuals, which have a unique static pattern in response to each fault. Then, the residual processor interrogates the residuals by matching them to one of several known patterns. It computes the probability of each hypothesis conditioned on the history of residuals. The fault detection latency is reduced by integrating the design of the residual generator and the residual processor. The vehicle health monitoring system is evaluated in real-time on a Buick LeSabre. The vehicle sensor and actuator faults are simulated artificially by the computer or created manually by the driver. In one experiment, a real intermittent sensor fault occurred and was immediately detected and identified. The real-time evaluation demonstrates that the vehicle health monitoring system can detect and identify actuator and sensor faults under various disturbances and uncertainties with almost minimal detection latency
Testing Cold Dark Matter with the Low-Mass Tully-Fisher Relation

In most cosmological theories, the galaxy mass function at small masses is related to the small-scale matter power spectrum. The circular velocity function (closely related to the mass function) is well studied for Local Group dwarfs. However, predictions and measurements are difficult for satellite galaxies because of ram pressure and tidal stripping. By contrast, isolated dwarf galaxies are less affected by these processes and almost always have 21 cm emission to trace their dynamics. Here we use isolated low-mass dwarf galaxies from the SDSS, with measured 21 cm widths, to test CDM cosmology. We find consistency between the predicted and observed number density of isolated galaxies down to -->Vmax ~ 50 km s−1. Our technique yields a direct test of small-scale cosmology that is independent of but weaker than the Lyα forest: warm dark matter particles heavier than 0.5 keV cannot be ruled out (for the case of thermal gravitinos). New, blind H I surveys are expected to uncover a much larger number of isolated low-mass galaxies and will increase the power of our constraints at small scales. Using our sample, we also find that the Tully-Fisher relation for dwarfs is a strong function of environment, and that the baryon fraction is only a weak function of galaxy mass. Together with the strong dependence of gas fraction on environment, these results indicate that for dwarf galaxies, gas loss and the end of star formation are dominated by external, not internal, processes.
Total Synthesis of Bistramide A

An asymmetric synthesis of the marine metabolite bistramide A is reported. The synthesis relies on the utility of three different organosilane reagents to construct all principle fragments and 8 of the 11 stereogenic centers of the natural product. [structure: see text].
On the Inverse and Determinant of Certain Truncated Wiener-Hopf Operators

The solution of a problem arising in integrable systems requires sharp asymptotics for the inverses and determinants of truncated Wiener-Hopf operators, both in the regular case (where the non-truncated Wiener-Hopf operator is invertible) and in singular cases. This paper treats two cases where the symbol of the Wiener-Hopf operator has Fisher-Hartwig singularities, one double zero or two simple zeros. We find formulas for the inverse that hold uniformly throughout the underlying interval with very small error, and formulas for the determinant with very small error.
Determination of thermal strains by moiré interferometry

An existing method is extended to measure thermal strain distributions on an absolute basis. Free thermal expansion and stress-induced deformations are separated, allowing the determination of coefficients of expansion, stress-induced strains, normal stresses and shear stresses. The method is applicable to many steady-state and transient thermal-strain problems.
NOVEL MAGNETIC PROPERTIES IN MULTI-WALLED CARBON NANOTUBE MATS: CONSISTENT WITH THE PARAMAGNETIC MEISSNER EFFECT DUE TO ULTRAHIGH-TEMPERATURE SUPERCONDUCTIVITY

We report magnetic measurements up to 1200 K on iron-contaminated multi-walled carbon nanotube mats with a Quantum Design vibrating sample magnetometer. Extensive magnetic data consistently show a ferrromagnetic transition at about 1000 K and a ferromagnetic-like transition at about 1275 K. The ferromagnetic transition at about 1000 K is associated with an Fe impurity phase and its saturation magnetization is in quantitative agreement with the Fe concentration measured by an inductively coupled plasma mass spectrometer. On the other hand, the saturation magnetization for the ferromagnetic-like phase (at 1275 K) is about four orders of magnitude larger than that expected from the measured concentration of Co or CoFe. We show that this ultrahigh-temperature ferromagnetic-like behavior cannot be explained by ferromagnetism of any Fe-carbon phases, carbon-based phases, or magnetic impurities, but is consistent with the paramagnetic Meissner effect (orbital ferromagnetism) due to the existence of π Josephson junctions in a granular superconductor.
Synthesis of alkylpyrroles by use of a vinamidinium salt

The synthesis of alkyl-substituted 2-pyrrolecarboxylate esters has been accomplished by the condensation reaction of a symmetrical vinamidinium salt and glycine ester derivatives.
Wettability Changes Induced by Adsorption of Asphaltenes

Asphaltene fractions were precipitated from two crude oils (designated as Prudhoe Bay `95 and Wyoming `95) by addition of n-hexane. A solution of 250 mg/L of asphaltenes in toluene was used to induce wettability changes in Berea sandstone cores by flow of asphaltene solutions through the core. Concentration of asphaltenes in the effluent was measured by ultraviolet (UV) absorbance. Wettability changes were assessed from measurements of the rate of spontaneous imbibition for changes in initial water saturation and brine composition. Water wetness decreased markedly with increase in ionic strength, increase in cation valency, and decrease in initial water saturation. For comparable conditions, changing the brine anions (chloride, nitrate, carbonate, and sulfate) caused lesser but fairly consistent changes in wetting. Wetting changes induced by asphaltenes from the Wyoming `95 crude oil were always higher than for those prepared from the Prudhoe Bay `95 crude oil. Waterflood recoveries for NaCl, CaCl{sub 2}, and AlCl{sub 3} brines (0.09 M) increased with decrease in water wetness, with recovery reaching a maximum at an Amott wettability index of about 0.2. This result agrees with results reported previously for wettability changes induced by adsorption from crude oil.
Operating systems architecture

Operating systems architecture refers to the overall design of hardware and software components and their operational effectiveness as a whole. To be effective, however, an operating system must not only be cognizant of the collection of hardware and software modules, but must also be designed in light of the programs and data which the system processes and the people which it serves. The absence of formal theory on operating systems and the lack of standard terminology have caused much confusion among users. The problem is particularly apparent when comparing systems where the same terms are applied to a variety of concepts and levels of implementation.
Coumarin base-pair replacement as a fluorescent probe of ultrafast DNA dynamics

The design and synthesis of a novel coumarin C-riboside are described, and is based on the well-known photoprobe Coumarin 102. A diastereofacial selective Heck coupling between a furanoid glycal and a coumarin triflate provided a method for glycoside formation. The coumarin C-glycoside was incorporated synthetically into DNA oligomers, and was used to probe ultrafast dynamics of duplex DNA using time-resolved Stokes shift methods.
Constraints on the redshift and luminosity distributions of gamma-ray bursts in an Einstein-de Sitter universe

Two models of the gamma-ray burst population, one with a standard candle luminosity and one with a power-law luminosity distribution, are ?2-fitted to the union of two data sets: the differential number versus peak flux distribution of BATSE's long-duration bursts and the time dilation and energy shifting versus peak flux information of pulse duration time dilation factors, interpulse duration time dilation factors, and peak energy shifting factors. The differential peak flux distribution is corrected for threshold effects at low peak fluxes and at short burst durations, and the pulse duration time dilation factors are also corrected for energy stretching and similar effects. Within an Einstein-de Sitter cosmology, we place strong bounds on the evolution of the bursts, and these bounds are incompatible with a homogeneous population, assuming a power-law spectrum and no luminosity evolution. Additionally, under the implied conditions of moderate evolution, the 90% width of the observed luminosity distribution is shown to be 102, which is less constrained than others have demonstrated it to be assuming no evolution. Finally, redshift considerations indicate that if the redshifts of BATSE's faintest bursts are to be compatible with that which is currently known for galaxies, a standard candle luminosity is unacceptable, and, in the case of the power-law luminosity distribution, a mean luminosity 1057 photons s-1 is favored.
Coherent detection of multiband terahertz radiation using a surface plasmon-polariton based photoconductive antenna

We demonstrate a dipole antenna that utilizes surface plasmons for enhanced sensitivity of narrowband coherent terahertz detection. We also describe properties of a multiband dipole detector that would allow for enhanced sensitivity at multiple frequencies.
Exchange Rate Economics

Much of the paper is devoted to expounding the standard model of the exchange rate accepted by most economists today. This regards the exchange rate as a forward-looking asset price. Its steady-state level is determined by the need to have a current account balance that will keep the debt/gross domestic product (GDP) ratio constant, while the path of adjustment toward this steady-state level is determined by the representative agent's rational expectation of what will happen between now and the long run. The paper then examines a number of criticisms of this model: that exchange rate changes are driven by 'news' and will be nonexistent in the absence of news; that it implies that chartist rules will systematically lose money; and that it leaves no room for 'bubble-and-crash' dynamics, which appear to have occurred. An alternative 'behavioral' model that gives room for such behavior is presented. The paper then argues that overvaluation can thwart development through an attack of 'Dutch disease,' and discusses the role that exchange rate policy may play in avoiding this outcome. This demands primarily the use of nonmonetary instruments like fiscal policy or capital controls, but the behavioral model of the exchange rate implies that intervention can also play a role. The paper also includes a discussion of the alternative exchange-rate regimes available.
Reliability in layered networks with random link failures

We consider network reliability in layered networks where the lower layer experiences random link failures. In layered networks, each failure at the lower layer may lead to multiple failures at the upper layer. We generalize the classical polynomial expression for network reliability to the multilayer setting. Using random sampling techniques, we develop polynomial-time approximation algorithms for the failure polynomial. Our approach gives an approximate expression for reliability as a function of the link failure probability, eliminating the need to resample for different values of the failure probability. Furthermore, it gives insight on how the routings of the logical topology on the physical topology impact network reliability. We show that maximizing the min cut of the (layered) network maximizes reliability in the low-failure-probability regime. Based on this observation, we develop algorithms for routing the logical topology to maximize reliability.
Orbit Determination Capability Analysis for the Mariner-Jupiter-Saturn 1977 Mission

Delivering a spacecraft to the outer planets with high precision (la « 200 km) and supporting the desired high accuracy instrument pointing near a planetary encounter place great demands on a navigation system. A combined Earth-based radio tracking/onboard optical data navigation system designed to meet these goals, is described in this paper. Some results of applying this navigation system to the preliminary Mariner-Jupiter-Saturn 1977 mission trajectories (the Jupiter approach of the JSX-flight and the Saturn approach of the JST-flight) are presented. It is shown that this system is capable of providing target planet centered orbit determination accuracies in the range of 100 Jem, and accuracies relative to closely encountered satellites of about 200-250 km, provided there is accurate modeling of the natural satellite motions. Analytical theories of the satellite motions would be attractive from the cost and time usage standpoint as alternatives to numerical integration of the equations of motion. An analytical theory (ignoring the mutual perturbations) is investigated for this role. It is concluded that further development of these theories will have to be undertaken before they can be used for high precision navigation.
Atomization of water jets and sheets in axial and swirling airflows

Axial and swirling airflows were used to break up water jets and sheets into sprays of droplets to determine the overall effects of orifice diameter, weight flow of air, and the use of an air swirler on fineness of atomization as characterized by mean drop size. A scanning radiometer was used to determine the mean drop diameter of each spray. Swirling airflows were produced with an axial combustor, 70 deg blake angle, air swirling. Water jets were injected axially upstream, axially downstream and cross stream into the airflow. In addition, pressure atomizing fuel nozzles which produced a sheet and ligament type of breakup were investigated. Increasing the weight flow rate of air or the use of an air swirling markedly reduced the spray mean drop size. Test conditions included a water flow rate of 68.0 liter per hour and airflow rates (per unit area) of 3.7 to 25.7 g per square cm per sec, at 293 K and inlet-air static pressures of 1.01 x 10 to the 5th to 1.98 x 10 to the 5th N/sq m.
The numeraire portfolio

Abstract A portfolio formed from a given list of assets is defined as a numeraire portfolio for the list if (a) it is self-financing, (b) its value is always positive, and (c) zero is always the best conditional forecast of the numeraire-dominated rate of return of every asset on the list. The numeraire portfolio exists if and only if there are no profit opportunities from trading assets on the list. For a sample list of heterogeneous assets (NYSE size-quintile portfolios, corporate bonds, and short-term bills), numeraire-dominated returns are similar to market-model forecast errors and, as abnormal return measures, clearly dominate market-adjusted returns.
Construction of field algebras with quantum symmetry from local observables

It has been discussed earlier that (weak quasi-) quantum groups allow for a conventional interpretation as internal symmetries in local quantum theory. From general arguments and explicit examples their consistency with (braid-) statistics and locality was established. This work addresses the reconstruction of quantum symmetries and algebras of field operators. For every algebraA of observables satisfying certain standard assumptions, an appropriate quantum symmetry is found. Field operators are obtained which act on a positive definite Hilbert space of states and transform covariantly under the quantum symmetry. As a substitute for Bose/Fermi (anti-) commutation relations, these fields are demonstrated to obey a local braid relation.