cssi/SciSciGPT-SciSciNet huggingface dataset:
Quadratic dynamical systems describing shear flow of non-newtonian fluids

Phase-plane techniques are used to analyze a quadratic system of ordinary differential equations that approximates a single relaxation-time system of partial differential equations used to model transient behavior of highly elastic non-Newtonian liquids in shear flow through slit dies. The latter one-dimensional model is derived from three-dimensional balance laws coupled with differential constitutive relations well-known by rheologists. The resulting initial-boundary-value problem is globally well-posed and possesses the key feature: the steady shear stress is a non-monotone function of the strain rate. Results of the global analysis of the quadratic system of ode’s lead to the same qualitative features as those obtained recently by numerical simulation of the governing pde’s for realistic data for polymer melts used in rheological experiments. The analytical results provide an explanation of the experimentally observed phenomenon called spurt; they also predict new phenoinena discovered in the numerical simulation; these phenomena should also be observable in experiments.
Effects of local injection of corticosteroids on the healing of ligaments : a follow-up report

One hundred and one skeletally mature New Zealand White rabbits were used to study the long-term effects of a single injection of corticosteroid on the biomechanical, histological, and biochemical properties of ligament-healing. Two steroid doses were studied, as previously described. The injections were made into a fascial pocket immediately after transection of the ligament. The animals were killed forty-two and eighty-four days after the injury. In our previous investigation, in which we examined the early (inflammatory and proliferative) phases of ligament-healing, the specimens that had been injected with a dose of steroids equivalent to that given to humans demonstrated significantly inferior biomechanical properties and histological organization relative to controls that had not received an injection. In the current study, we examined the later (remodeling and maturation) phases of ligament-healing and found that the tensile strength (the ultimate stress) of the specimens that had been injected with the steroids returned to a value that was equal to that of the controls that had not received an injection; however, the peak load of the specimens that had been injected with steroids remained inferior to that of the controls. This was accompanied by a lag in the histological maturation.
Sequential Monte Carlo Methods for Estimating Dynamic Microeconomic Models

SUMMARY This paper develops estimators for dynamic microeconomic models with serially correlated unobserved state variables using sequential Monte Carlo methods to estimate the parameters and the distribution of the unobservables. If persistent unobservables are ignored, the estimates can be subject to a dynamic form of sample selection bias. We focus on single-agent dynamic discrete-choice models and dynamic games of incomplete information. We propose a full-solution maximum likelihood procedure and a two-step method and use them to estimate an extended version of the capital replacement model of Rust with the original data and in a Monte Carlo study. Copyright © 2015 John Wiley & Sons, Ltd.
Chemical Evolution of the Galactic Disk and Bulge

The Milky Way Galaxy offers a unique opportunity for testing theories of galaxy formation and evolution. The study of the spatial distribution, kinematics and chemical abundances of stars in the Milky Way Galaxy allows one to address specific questions pertinent to this meeting such as
Corruption in economic development - beneficial grease, minor annoyance, or major obstacle?

Corruption is a major obstacle to economic development. It reduces domestic investment, discourages foreign direct investment, inflates government spending, and shifts government spending away from education, health, and infrastructure maintenance toward less efficient (more manipulable) public projects. International pressure against corruption is useful, but more critical is reform of domestic institutions and a focus on the incentive problem. Abuse of power by public officials should not pay. Wei reviews the overwhelming statistical evidence that countries with high levels of corruption experience poor economic performance. Corruption hinders economic development by reducing domestic investment, discouraging foreign direct investment, encouraging overspending in government, and distorting the composition of government spending (away from education, health, and infrastructure maintenance toward less efficient but more manipulable public projects). The World Bank and the International Monetary Fund, among others, define corruption as the abuse of public office for private gains. Whenever a public office is abused, a public function or objective is set aside and compromised. Only if a public function is unproductive are policy goals unharmed by corruption. But one often hears that bribery greases the machinery of commerce, so Wei studied the evidence-which clearly rejects that hypothesis. Culture shapes the difference between a bribe and a gift but culturally induced differences seem small. There is no evidence to support the notion that corruption in Asia, including East Asia, entails lesser consequences. Corruption can be symptomatic of many social ills so the fight against it must be multifaceted. Laws and law enforcement are indispensable, but countries serious about fighting corruption should also reform government's role in the economy, especially in areas that (by giving officials discretionary power) are hotbeds of corruption. Recruiting and promoting civil servants on the basis of merit and paying them a salary competitive with similar jobs in the private sector helps attract moral, high-quality civil servants. International pressure on corrupt countries, and also to criminalize the bribing of foreign officials by multinational firms, can be useful. But anti-corruption campaigns cannot succeed without reforming domestic institutions in the corrupt countries. This paper - a product of Public Economics, Development Research Group - is part of a larger effort in the group to study questions on accountability and governance. The author may be contacted at shang-jin_wei@harvard.edu.
Introduction: Paleoheliosphere versus PaleoLISM

Speculations that encounters with interstellar clouds modify the terrestrial climate have appeared in the scientific literature for over 85 years. This article introduces a series of articles that seek to give substance to these speculations by examining the exact mechanisms that link the pressure and composition of the interstellar medium surrounding the Sun to the physical properties of the inner heliosphere at the Earth.
A Calculus for Causal Relevance

We present a sound and complete calculus for causal relevance that uses Pearl's functional causal models as semantics. The calculus consists of axioms and rules of inference for reasoning about causal relevance relationships. We extend the set of known axioms for causal relevance with new axioms and rules of inference. The axioms are then divided into different sets for reasoning about specific subclasses of models. These subclasses make up a new decomposition of the class of causal models. At the end, we show how the calculus for causal relevance can be used in the task of identifying causal structure from non-observational data.
Minimal surfaces with the area growth of two planes: The case of infinite symmetry

We prove that a connected properly immersed minimal surface in with infinite symmetry group and area growth constant less than is a plane, a catenoid, or a Scherk singly-periodic minimal surface. As a consequence, the Scherk minimal surfaces are the only connected periodic minimal desingularizations of the intersections of two planes
A new companion to Capparelli's identities

We discuss a new companion to Capparelli's identities. Capparelli's identities for m = 1 , 2 state that the number of partitions of n into distinct parts not congruent to m, -m modulo 6 is equal to the number of partitions of n into distinct parts not equal to m, where the difference between parts is greater than or equal to 4, unless consecutive parts are either both consecutive multiples of 3 or add up to a multiple of 6. In this paper we show that the set of partitions of n into distinct parts where the odd-indexed parts are not congruent to m modulo 3, the even-indexed parts are not congruent to 3 - m modulo 3, and 3 l + 1 and 3 l + 2 do not appear together as consecutive parts for any integer l has the same number of elements as the above mentioned Capparelli's partitions of n. In this study we also extend the work of Alladi, Andrews and Gordon by providing a complete set of generating functions for the refined Capparelli partitions, and conjecture some combinatorial inequalities.
The growth of red sequence galaxies in a cosmological hydrodynamic simulation

We examine the cosmic growth of the red sequence in a cosmological hydrodynamic simulation that includes a heuristic prescription for quenching star formation that yields a realistic passive galaxy population today. In this prescription, haloes dominated by hot gas are continually heated to prevent their coronae from fuelling new star formation. Hot coronae primarily form in haloes above ∼1012 M⊙, so that galaxies with stellar masses ∼1010.5 M⊙ are the first to be quenched and move on to the red sequence at z > 2. The red sequence is concurrently populated at low masses by satellite galaxies in large haloes that are starved of new fuel, resulting in a dip in passive galaxy number densities around ∼1010 M⊙. Stellar mass growth continues for galaxies even after joining the red sequence, primarily through minor mergers with a typical mass ratio ∼1:5. For the most massive systems, the size growth implied by the distribution of merger mass ratios is typically approximately two times the corresponding mass growth, consistent with observations. This model reproduces mass–density and colour–density trends in the local Universe, with essentially no evolution to z = 1, with the hint that such relations may be washed out by z ∼ 2. Simulated galaxies are increasingly likely to be red at high masses or high local overdensities. In our model, the presence of surrounding hot gas drives the trends with both mass and environment.
Coincidence invariants and higher Reidemeister traces

The Lefschetz number and fixed point index can be thought of as two different descriptions of the same invariant. The Lefschetz number is algebraic and defined using homology. The index is defined more directly from the topology and is a stable homotopy class. Both the Lefschetz number and index admit generalizations to coincidences and the comparison of these invariants retains its central role. In this paper, we show that the identification of the Lefschetz number and index using formal properties of the symmetric monoidal trace extends to coincidence invariants. This perspective on the coincidence index and Lefschetz number also suggests difficulties for generalizations to a coincidence Reidemeister trace.
Quantitative Analysis of Crisis : Crisis Identification and Causality

Studies use different conceptual and operational definitions of crises. The different crisis identifications can lead to inconsistent conclusions and policy formulation even if the same analytical framework is applied. Also, most studies focus on only a few types of crises. This narrow focus on crises may not capture the multidimensionality of crises. Seven crisis types are analyzed, namely (1) liquidity type banking crises, (2) solvency type banking crises, (3) balance of payments crises, (4) currency crises, (5) debt crises, (6) growth rate crises, and (7) financial crises. Crisis data were collected from 15 emerging economies in 1980-2002 on a quarterly basis. The crisis identification exercise finds that multidimensionality in which different crisis types occur in short periods is one of the most important characteristics of recent crises. Further, the Granger causality tests in five Asian economies (Indonesia, the Republic of Korea, Malaysia, the Philippines, and Thailand) find that currency crises tend to trigger other types of crises, and therefore exchange rate management is essential.
Observational evidence for a correlation between jet power and black hole spin

We show that the 5-GHz radio flux of transient ballistic jets in black hole binaries correlates with the dimensionless black hole spin parameter a* estimated via the continuum-fitting method. The data suggest that jet power scales either as the square of a* or as the square of the angular velocity of the horizon ΩH. This is the first direct evidence that jets may be powered by black hole spin energy. The observed correlation validates the continuum-fitting method of measuring spin. In addition, for those black holes that have well-sampled radio observations of ballistic jets, the correlation may be used to obtain rough estimates of their spins.
Poverty and Regional Development in Eastern Europe and Central Asia

This paper is focused only on this objective: the alleviation of regional concentrations of poverty. There are several reasons. First, judging from the public documents of multilaterals and governments, poverty reduction is often the primary objective of regional development efforts in the ECA region. It is also the primary objective of the World Bank, the sponsor of this paper. Second, the environmental and social objectives of regional development are difficult to analyze through an economic lens. While some may argue that cities are too big, others argue that large cities are crucial to economic growth and merely need to be better managed. By the same token, the social costs of out-migration are difficult to weigh against the economic benefits of labor mobility. The analysis of the tradeoffs between the environmental and social objectives of regional development on one hand, and economic objectives of regional development on the other, is better done on a case-by-case basis than in a regional survey paper. This report is the first of a series of papers on regional issues in the ECA region.
High-Pressure Studies of Ionic Conductivity in Solids

Publisher Summary The chapter presents a discussion on high-pressure studies of ionic conductivity in solids. The chapter presents a review and discusses hydrostatic pressure studies performed on a variety of ionic conductors. The chapter presents discussion on the experimental results and their interpretation in terms of relevant concepts and theory. The chapter presents examples, which illustrate special features or show systematic trends or both. Much of the available pressure work has been on relatively simple materials and crystal structures because these are amenable to theoretical treatment. Some of the materials investigated (for example, PbF2 and the thallous halides) are especially interesting because, among other properties, they possess large dielectric constants and also exhibit relatively soft, low-lying phonon modes. These factors are important in relation to ionic conduction because the larger the dielectric constant of an ionic crystal, the lower the energy of formation of lattice defects. Also, physically, ionic transport occurs by hopping motion across an energy barrier, and this barrier might be expected to become smaller the “softer” the lattice. The chapter presents analysis on the evidence for the connection between these properties and the transport properties. The chapter presents a brief theoretical background with some of the concepts and results necessary for the analysis and interpretation. For this purpose it was found most convenient to divide the substances of interest into several groupings as follows: alkali halides (both NaCl and CsCl types), silver halides, thallium halides, fluorites and related structures, and fast ion conductors.
Explosions triggered by violent binary–star collisions: application to Eta Carinae and other eruptive transients

This paper discusses a scenario where a violent periastron collision of stars in an eccentric binary system induces an eruption or explosion seen as a brief transient source, attributed to luminous blue variables (LBVs), supernova (SN) impostors or other transients. The key ingredient is that an evolved primary increases its photospheric radius on relatively short (year to decade) time-scales, to a point where the radius is comparable to or larger than the periastron separation in an eccentric binary. In such a configuration, a violent and sudden collision would ensue, possibly leading to substantial mass ejection instead of a merger. Sudden energy deposition during the encounter could drive expansion of the optically thick envelope, causing a luminous transient source. Repeated periastral grazings in an eccentric system could quickly escalate to a catastrophic encounter. Outbursts triggered by tidal disturbances or powered by secondary accretion of the primary star’s wind have been suggested previously. Instead, this paper proposes a much more violent encounter where the companion star plunges deep inside the photosphere of a bloated primary during periastron, as a result of the primary star increasing its own radius. This is motivated by the case of Eta Carinae, where such a collision must have occurred if conventional estimates of the present-day orbit are correct and where peaks in the light curve coincide with times of periastron. Stellar collisions may explain brief recurring LBV outbursts, such as SN 2000ch and SN 2009ip, and perhaps outbursts from intermediate-mass progenitor stars (i.e. collisions are not necessarily the exclusive domain of very luminous stars), but they cannot explain all non-SN transients. Finally, mass ejections induced repeatedly at periastron cause orbital evolution; this may explain the origin of eccentric Wolf–Rayet binaries such as WR 140.
Non‐conventional Energy Sources for Green Synthesis in Water (Microwave, Ultrasound, and Photo)

The most important goal for chemists is to ensure that the next generation of synthetic protocols for drugs and fine chemical synthesis is more sustainable and greener than the current generation. This can be achieved using non-conventional energy sources, such as microwave, ultrasound, and photochemical chemistry, in conjugation with aqueous reaction media, which dramatically reduce chemical waste and reaction times. This chapter summarizes recent developments in this area. Keywords: alternative energy sources; organic synthesis; water; microwave irradiation; ultrasound irradiation; photochemistry; green chemistry
Goal Setting and Energy Conservation

Abstract This paper develops a theoretical model of consumer demand for an energy conservation program that involves non-binding, self-set goals. We present evidence from a Northern Illinois goal-setting program, aimed at reducing residential electricity consumption, which is difficult to reconcile with standard preferences and is broadly consistent with a model of present-biased consumers with reference-dependent preferences. We find that the need for commitment is correlated with program adoption, higher pre-adoption consumption, and lower responsiveness to goals. Consumers choosing realistic goals persistently save substantially more, achieving savings of nearly 11%, than those choosing very low or unrealistically high goals.
Explaining the gender gap in U.S. presidential elections, 1980-1992

This article compares the voting behavior of women and men in presi dential elections since 1980. We test whether the different levels of salience which men and women attribute to different issues ...
Conditional workflow management: A survey and analysis

Workflows form the essential part of the process execution both in a single machine and in distributed environments. Although providing conditional structures is not mandatory for a workflow management system, support for conditional workflows is very important in terms of error handling, flexibility and robustness. Several of the existing workflow management systems already support conditional structures via use of different constructs. In this paper, we study the most widely used workflow management systems and their support for conditional structures such as if, switch, and while. We compare implementation of common conditional structures using each of these workflow management systems via case studies, and discuss capabilities of each system.
Gamma-ray bursts from quark stars

Long gamma-ray bursts (GRBs) are believed to be related to the explosion of Type Ic supernovae, which have been stripped of their hydrogen and helium envelopes. There appear to be two types of these explosions: those that are approximately spherical (GRB 980425/SN 1998bw), and which are associated with weak bursts; and the classical GRBs which generate ultrarelativistic jets (GRB 030329/SN 2003dh). If this bimodality is real, Swift will provide clear evidence for it. We propose that classical powerful GRBs, which generate ultrarelativistic outflows, are a result of the formation of quark stars. Quark stars may provide additional energy for the explosion of Type Ic supernovae, but far more important is the creation of a surface which acts as a membrane that cannot be penetrated by baryons. A surface of a quark star allows only ultrarelativistic matter to escape: photons, neutrinos, electron–positron pairs and magnetic fields. The formation of a quark star follows several minutes after the initial core collapse. Possible evidence for this time delay is provided by BATSE precursors to GRBs, as analysed by Lazzati.
Trigonometric Series via Laplace Transforms

In another Note in this Magazine [2], I presented a method that uses the Laplace transform to find exact values for a large class of convergent series of rational terms. Recently, also in the Magazine, Lesko and Smith [3] revisited the method and demonstrated an extension of the original idea to additional infinite series. My inten tion in this note is to illustrate the power of the technique in the case of trigonometric series.
Impact of geoengineering schemes on the terrestrial biosphere

[1] Climate stabilization via “Geoengineering” schemes seek to mitigate climate change due to increased greenhouse gases by compensating reduction in solar radiation incident on earth's surface. In this paper, we address the impact of these climate stabilization schemes on terrestrial biosphere using equilibrium simulations from a coupled atmosphere-terrestrial biosphere model. Climate stabilization would tend to limit changes in vegetation distribution brought on by climate change, but would not prevent CO2-induced changes in Net Primary Productivity (NPP) or biomass; indeed, if CO2 fertilization is significant, then a climate-stabilized world could have higher NPP than our current world. Nevertheless, there are many reasons why geoengineering is not a preferred option for climate stabilization.
Zinc Sulfide/Gallium Phosphide Composites by Chemical Vapor Transport

Chemical vapor transport was employed to prepare ZnS/ GaP composite powders. Spherical, submicrometer, nano- porous ZnS powders were used as a substrate, where GaP was deposited via a transport reaction involving iodine. XRD examinations of the powders with various GaP contents indicated that the powders consisted mainly of solid solutions with small amounts of GaP and ZnS. The powders were then densified to greater than 98% relative densities by cold isostatic pressing followed by hot isostatic pressing at 900deg;C under 207 MPa. Vickers hardness improved from 1.38 GPa for pure ZnS to 2.82 GPa (13.7 wt% GaP) and fracture toughness increased from 0.50 MPa.m1/2 for pure ZnS to 0.89 MPa.m1/2 (21.0 wt% GaP).
Content and consciousness

Preface to the Routledge Classics Edition Preface to the Second Edition Preface to the First Edition Part 1: The Language of the Mind I. The Ontological Problem of the Mind 1. The Mind and Science 2. Existence and Identity II. Intentionality 3. The Problem of Intentionality 4. Two Blind Alleys 5. The Way Out III. Evolution of the Brain 6. The Intelligent Use of Information 7. The Evolution of Appropriate Structures 8. Goal-directed Behaviour IV. The Ascription of Content 9. Function and Content 10. Language and Content 11. Personal and Sub-Personal Levels and Explanation: Pain Part 2: Consciousness V. Introspective Certainty 12. The Certainty of Certain Utterances 13. A Perceiving Machine VI. Awareness and Consciousness 14. The Ordinary Words 15. Awareness and Control 16. Consciousness VII. Mental Imagery 17. The Name of Images and the Introspective Trap 18. Colours VIII Thinking and Reasoning 19. People and Processes 20. Reasons and Causes IX. Actions and Intentions 21. Intentional Actions 22. Willing 23. The Importance of Intentional Actions X. Language and Understanding 24. Knowing and Understanding 25. Language and Information 26. Conclusions Index
Measurements of Medium-Frequency Propagation Characteristics of a Transmission Line in an Underground Coal Mine

In underground coal mines, medium frequency (MF) communication systems couple their signals to metal infrastructures such as ac power cables and wire-based telephone lines, which guide the signals to propagate for a long distance. To better understand the propagation characteristics of MF signals, an easy-to-use measurement method was recently developed at the National Institute for Occupational Safety and Health. The method will be introduced along with an equivalent transmission line model for a long metallic infrastructure in underground coal mines. The model serves as the fundamental driver for the method development. Propagation measurements on a twisted pair of telephone lines in an underground mine were made using this method. The measurements confirmed the low MF signal attenuation rate and the dependence of the propagation characteristics of the line on the electrical properties of surrounding coal and rock as theoretical studies predicted.
Soft condensed matter physics

Abstract Soft condensed matter physics is the study of materials, such as fluids, liquid crystals, polymers, colloids and emulsions, that are “soft” to the touch. This article will review some properties, such as the dominance of entropy, that are unique to soft materials and some properties such as the interplay between broken-symmetry, dynamic mode structure and topological defects that are common to all condensed matter systems but which are most easily studied in soft systems.
Irradiation effects in high temperature superconductors

Abstract Irradiation effects on Tl- and Y-based high temperature superconductors (HTS) are compared. Ion irradiation can enhance the critical current density (Jc) at low fluences through the interaction of defects with the flux lattice, and at higher fluences ion irradiation can degrade the superconducting transition temperature (Tc) and increase the normal state resistivity (τ). Low-fluence irradiation of Tl2Ca2Ba2Cu3O10 (Tl-2223) single crystals was shown to increaseJc by an order of magnitude over Jc for unirradiated crystals. Similarly, irradiated YBa2Cu3O7−δ (YBCO) crystals have increased Jcs by factors of 2 to 100; however, the effects of irradiation on thin-film HTS from these two materials depends greatly on their crystalline quality. Ion irradiation of millimeter grain-size Tl-2223 films was shown to increase Jc while similar irradiation of ∼ 10 μm grain-size Tl-2223 films had little effect on Jc. For ions with energies less than several MeV amu , the dominant mechanism causing irradiation-induced degradation of Tc. is collisional damage. Both Tl-based and YBCO superconductors behave similarly in that Tc decreases linearly with the level of damage: yet, the rate of decrease in Tc for Tl-based superconductors (5000 K dpa ) was approximately twice that for irradiated YBCO. An examination of the temperature behavior and rate of damage recovery of τ yielded an activation energy of 0.36 eV for annealing defects.
Techniques for Small-Signal Analysis of Semiconductor Devices

Techniques for ascertaining the small-signal behavior of semiconductor devices in the context of numerical device simulation are discussed. Three standard approaches to this problem will be compared: (i) transient excitation followed by Fourier decomposition, (ii) incremental charge partitioning, and (iii) sinusoidal steady-state analysis. Sinusoidal steady-state analysis is shown to be the superior approach by providing accurate, rigorously correct results with reasonable computational cost and programming commitment.
Effect of suction on controlling the secondary instability of boundary layers

The effect of suction on controlling the three‐dimensional secondary instability is investigated for a boundary layer with a pressure gradient in the presence of a small but finite‐amplitude Tollmien–Schlichting wave. The focus is on the principal parametric resonance responsible for the strong growth of subharmonics in a low disturbance environment. Calculations are presented for the effect of suction on the onset and amplification of the secondary instability in Blasius and Falkner–Skan flows, as well as its effect on controlling the production of the vortical structure.
Back propagation of acoustic signature for robust target identification

The Acoustic Signal Processing branch of the U.S. Army Research Laboratory has demonstrated, using the output of microphone arrays of battlefield acoustic sensors, that harmonic lines are effective spectral features for the target identification of acoustic signatures from ground vehicles such as tanks and trucks. However, battlefield acoustic target identification is extremely challenging because of the variations in the signature caused by the environmental effects on the acoustic propagation, vehicle operating characteristics (e.g. gear, load) and target dynamics such as range, velocity, and aspect. The utilization of air acoustic propagation models to normalize the spectral features can be used to mitigate a significant portion of this variability for robust battlefield acoustic target identification. The integration of acoustic propagation models is a new approach, and potentially represents a very significant improvement to current target recognition methods.
Generation of Cyclic Stress-Strain Curves for Sheet Metals

The main objective of this paper is to obtain the first few stress-strain loops of sheet metals from reverse loading so that the springback can be simulated accurately, Material parameters are identified by an inverse method within a selected constitutive model that represents the hardening behavior of materials subjected to a cyclic loading. Three-point bending tests are conducted on sheet steels (mild steel and high strength steel). Punch stroke, punch load, bending strain, and bending angle are measured directly during the tests. Bending moments are then computed from these measured data. Bending moments are also calculated based on a constitutive model. Normal anisotropy and nonlinear isotropic/kinematic hardening are considered. Material parameters are identified by minimizing the normalized error between two bending moments. Micro-genetic algorithm is used in the optimization procedure. Stress-strain curves are generated with the material parameters found in this way, which can be used with other plastic models.
Construction of the Courant-Snyder invariants for the non-linear equations of motion under presence of the linear coupling

A single particle subjected to an arbitrary static magnetic field, which includes skew-quadrupole and solenoidal fields, is considered. The Courant-Snyder invariants are constructed, and the long-term stability of the beam in a storage ring is formulated in terms of the normal modes. The generalized Courant-Snyder invariants become Lyapunov functions when the new generalized B-functions admit non-zero lower and finite upper bounds.
Tailoring aqueous solvents for organic reactions: Heck coupling reactions in high temperature water

Abstract High temperature water is demonstrated to be an effective solvent for Heck coupling reactions of aromatic halides with cyclic alkenes without the addition of co-solvents or specialized ligands. Reactions in the presence of LiCl and quaternary ammonium salts indicate that the reaction takes place in the aqueous phase.
Effect of Unsteady Wake Passing Frequency on Boundary Layer Transition, Experimental Investigation, and Wavelet Analysis

Detailed experimental and theoretical investigations were carried out to study the effect of unsteady wake passing frequency on the boundary layer transition along the concave surface of a curved plate wider a zero longitudinal pressure gradient. Periodic unsteady flow with different passing frequencies is generated utilizing an unsteady flow research facility with a rotating cascade of rods positioned upstream of the curved plate. Extensive unsteady boundary layer measurements are carried out. The data are analyzed using conventional and wavelet-based methods. Local time scales are defined as those of the most energetic fluctuations. and are calculated from wavelet transforms of the velocity signals. The dominant time scales are mapped as functions of the distance to the plate the downstream location, and the phase relative to the wake-passing. Furthermore, conditional sampling is applied laminar and turbulent time scales are calculated and the effects of wake passing frequency on these scales are shown
Oscillator Strengths for B-X, C-X, and E-X Transitions in Carbon Monoxide

Band oscillator strengths for electronic transitions in CO were obtained at the Synchrotron Radiation Center of the University of Wisconsin-Madison. Our focus was on transitions observed in interstellar spectra with the Far-Ultraviolet Spectroscopic Explorer; these transitions are also important in studies of selective isotope photodissociation, where fractionation among isotopomers can occur. Absorption from the ground state X 1Σ+ (v'' = 0) to A 1Π (v' = 5), B 1Σ+ (v' = 0, 1), C 1Σ+ (v' = 0, 1), and E 1Π (v' = 0) was measured. Fits to the A-X (5, 0) band, whose oscillator strength is well known, yielded the necessary column density and excitation temperature. These parameters were used in a least-squares fit of the observed profiles to extract the band oscillator strengths of the transitions of interest. Our oscillator strengths are in excellent agreement with results from recent experiments using a variety of techniques. This agreement provides the basis for a self-consistent set of f-values at far-ultraviolet wavelengths for studies of interstellar (and stellar) CO.
The Effect of Wire Rope Mechanics on the Material Properties of Cord Composites: An Elasticity Approach

An analytical model is presented for the behavior of cord reinforced rubber composite plates taking into account the extension-twisting coupling of the cord based on an equilibrium formulation. The effect of the cord mechanics on the unidirectional lamina properties is investigated for various modulus ratios and geometries. The equations of equilibrium are derived for the unidirectional plate. Solutions are found for the following plate problems, uniaxial tension along the cord direction, uniaxial tension perpendicular to the cord direction, and pure shear. These solutions are used to obtain average material properties and to investigate the influence of cord mechanics on the plate response. For very flexible synthetic rubbers, the behavior of the unidirectional lamina exhibits a good deal of extension twisting coupling, whereas for stiffer vulcanized rubbers, the rubber acts to restrain the cords from unwinding.
Effect of cathode and electrolyte transport properties on chromium poisoning in solid oxide fuel cells

Abstract A major degradation mechanism in solid oxide fuel cells (SOFCs) is poisoning of the cathode by chromium from volatilization of the interconnect material. The chromium deposition has been attributed to both chemical and electrochemical mechanisms. For an electrochemical reaction, deposition can occur only where both ions and electrons are available, which, for a purely ionic conducting electrolyte and a purely electronic conducting cathode, can occur only at the three-phase gas–electrolyte–electrode interface. However, the introduction of ionic conductivity into the cathode or electronic conductivity into the electrolyte can allow deposition to occur away from this three-phase interface, and thus alter its effect on the fuel cell performance. In this paper, the chromium poisoning of SOFC cathodes is reviewed, with a focus on the effects of the transport properties of the cathode and electrolyte materials.
The gas-phase oxidation of organic sulfur compounds

Etude de l'oxydation atmospherique des sulfures et thiols; de leurs reactions avec O( 3 P), O( 1 D), O 3 , HO, NO 2 et NO 3 ; et des reactions du radical CH 3 S avec O 2 , NO et NO 2
Concise chemical synthesis of β-homonojirimycin and related compounds

β-Homonojirimycin 2 was prepared in 27% overall yield from tetra-O-benzyl-d-glucono-1,5-lactone by way of the double reductive amination of a 2,6-heptodiulose (7). This synthetic approach provided also access to the 1,N-anhydro derivative of 2, compound 3. Aziridines of this type are potential inactivators of glycosidases.
THz beamforming using graphene-based devices

Graphene, a one-atom-thick carbon sheet with electronically tunable electromagnetic properties, has an interesting terahertz response, currently explored in a variety of applications. In this work, we put forward the design and realization of graphene nanodevices for THz phase modulation and beamforming, of large interest to sensing and wireless communication systems at THz frequencies. We present various designs for ultracompact, voltage-controlled phase-shifting devices that may tailor the phase and wavefront of a signal to achieve high-data-rate, inter-/intra-chip communications as well as interference management.
NICMOS Coronagraphic Observations of 55 Cancri

We present new near-infrared (1.1 μm) observations of the circumstellar environment of the planet-bearing star 55 Cancri. With these Hubble Space Telescope (HST) images we are unable to confirm the observation of bright scattered radiation at longer NIR wavelengths previously reported by Trilling and coworkers. NICMOS coronagraphic images with detection sensitivities to ~100 μJy arcsec-2 at 1.1 μm in the region 28–60 AU from the star fail to reveal any significant excess flux in point-spread function (PSF) subtracted images taken in two HST orbits. These new observations place flux densities in the 19–28 AU zone at a factor of 10 or more below the reported ground-based observations. Applying a suite of a dozen well-matched coronagraphic reference PSFs, including one obtained in the same orbits as the observations of 55 Cnc, yielded consistently null results in detecting a disk. We also searched for and failed to find a suggested flux-excess anisotropy in the ratio of ~1.7 : 1 in the circumstellar background along and orthogonal to the plane of the putative disk. We suggest that, if such a disk does exist, then the total 1.1 μm spectral flux density in an annular zone 28–42 AU from the star must be no more than ~0.4 mJy, at least 10 times smaller than suggested by Trilling and Brown, upon which their very large estimate for the total dust mass (0.4 M⊕) was based. Based on the far-infrared and submillimeter flux of this system and observations of scattered light and thermal emission from other debris disks, we also expect the intensity of the scattered light to be at least an order of magnitude below our upper limits.
A one-pot multicomponent coupling reaction for the stereocontrolled synthesis of (Z)-trisubstituted allylic alcohols.

In this Communication, we outline a new one-pot, multicomponent coupling reaction that allows easy access to (Z)-trisubstituted allylic alcohols. Our strategy is based on E to Z isomerization of th...
Parity and fermions in front-form: an unexpected result

Abstract We show that under the operation of parity the front-form ( 1 2 , 0) and (0, 1 2 ) Weyl spinors (massive or massles) do not get interchanged. This has the important consequence that if a front-form theory containing ( 1 2 , 0) ⊛ (0, 1 2 ) representation space has to be parity covariant then one must study the evolution of a physical system not only along x+ but also along the x− direction. As a result of our analysis, we find an indication that there may be no halving of the degrees of freedom in the front form of field theories.
Rocky mountain spotted fever.

Western physicians are offered an unusual opportunity for study of Rocky Mountain spotted fever, one not commonly extended their colleagues in other sections of the country. Since identification of the first cases of the disease in the East shortly more than a decade ago, tick fever has stimulated additional interest among members of the profession from year to year because of the apparent rapid dissemination throughout our nation. Those in practice elsewhere are for the most part unfamiliar with manifestations of the disease. There is a distinct obligation to furnish them with accurate information regarding it. The subject of tick fever is an extensive one. No attempt should be made in a single article to deal with its numerous phases but rather to select those of major importance and to present material for further thought and consideration on a disease entity which can in time assume proportions of grave national
Geometric non-vanishing

We consider L-functions attached to representations of the Galois group of the function field of a curve over a finite field. Under mild tameness hypotheses, we prove non-vanishing results for twists of these L-functions by characters of order prime to the characteristic of the ground field and more generally by certain representations with solvable image. We also allow local restrictions on the twisting representation at finitely many places. Our methods are geometric, and include the Riemann-Roch theorem, the cohomological interpretation of L-functions, and monodromy calculations of Katz. As an application, we prove a result which allows one to deduce the conjecture of Birch and Swinnerton-Dyer for non-isotrivial elliptic curves over function fields whose L-function vanishes to order at most 1 from a suitable Gross-Zagier formula.
The abundance of water and rock in Jupiter as derived from interior models

Abstract Models of Jupiter's interior were computed using a new molecular hydrogen equation of state, and a more precise algorithm for computing gravitational moments. Models with H/He ratios of 13.5, 11.25, and 10 were computed, and it was found that the models had rocky cores of 16 to 18 Earth masses and envelopes with 20 to 50 Earth masses of water. Models with temperatures of less than 180°K at 1 bar had water-to-rock ratios which were less than the solar value, thus removing a difficulty of previous computations. Models were also constructed in which rock was put into the envelope in place of water. It was found that, to a good approximation, a given mass of rock will replace an equal mass of water. At present the two cases are indistinguishable.
Preliminary investigation of a hybrid method for solving partial differential equations

In the digital computer solution of a partial differential equation involving both time and spatial variables the partial differential equation is approximated by difference equations arising from the discretization of both the time and spatial variables. The number of difference equations equals the number of spatial mesh points or stations times the number of time increments. In the analog computer solution of a partial differential equation the equation may be approximated by a set of coupled ordinary differential equations, one equation for each station. The set of differential equations is then solved simultaneously. Unless the problem is simple and the number of stations is small, digital computation may take a long time and analog computation may involve much equipment. The present investigation is an attempt to indicate a profitable way to solve partial differential equations with hybrid computation, using only a limited number of high speed analog components for integration and employing the digital computer for function storage and playback.
Fully Dense, Aluminum-Rich Al-CuO Nanocomposite Powders for Energetic Formulations

The thermite reaction between Al and CuO is well known and highly exothermic. For a conventional thermite mixture, the reaction is rate limited by a slow heterogeneous mass transfer at the metal and oxide interface. The relatively low reaction rate and ignition difficulty have restricted practical applications for this reaction. For newly developed nanocomposed thermites, the interface area is substantially increased resulting in a much higher reaction rate and a new range of possible applications. A top-down approach to preparation of reactive nanocomposite materials in the Al-rich Al-CuO system is discussed in this paper. The materials are prepared using arrested reactive milling, a technique based on high-energy ball milling performed at room temperature and stopped (or arrested) before the exothermic reaction between Al and CuO is triggered mechanically. The products are micron-sized, fully dense powders in which reactive components are uniformly mixed on the nanoscale. Optimized milling conditions fo...
Photodecomposition of 1,2-difluoro-1,2-di-iodoethene: formation of 1,2-difluoroethyne

Abstract Photolysis of trans-1,2-difluoro-1,2-di-iodoethene with 248 nm radiation from an excimer laser yielded difluoroethyne, cis-1,2-difluoro-1,2-di-iodoethene and 1,2,3,4-tetrafluoro-3,4-di-iodocyclobutene. Potential pathways for these products are presented in terms of the energetics of the reaction, and the dependencies of product formation on pressure and extent of conversion are discussed.
Clones: what is that smell?

Clones are generally considered bad programming practice in software engineering folklore. They are identified as a bad smell (Fowler et al. 1999) and a major contributor to project maintenance difficulties. Clones inherently cause code bloat, thus increasing project size and maintenance costs. In this work, we try to validate the conventional wisdom empirically to see whether cloning makes code more defect prone. This paper analyses the relationship between cloning and defect proneness. For the four medium to large open source projects that we studied, we find that, first, the great majority of bugs are not significantly associated with clones. Second, we find that clones may be less defect prone than non-cloned code. Third, we find little evidence that clones with more copies are actually more error prone. Fourth, we find little evidence to support the claim that clone groups that span more than one file or directory are more defect prone than collocated clones. Finally, we find that developers do not need to put a disproportionately higher effort to fix clone dense bugs. Our findings do not support the claim that clones are really a "bad smell" (Fowler et al. 1999). Perhaps we can clone, and breathe easily, at the same time.