cssi/SciSciGPT-SciSciNet huggingface dataset:
The Influence of Magnetic Field Geometry on the Evolution of Black Hole Accretion Flows: Similar Disks, Drastically Different Jets

Because the magnetorotational instability is capable of exponentially amplifying weak pre-existing magnetic fields, it might be hoped that the character of the magnetic field in accretion disks would be independent of the nature of the seed field. However, the divergence-free nature of magnetic fields in highly conducting fluids ensures that their large-scale topology is preserved, no matter how greatly the field intensity is changed. By performing global two- and three-dimensional general relativistic magnetohydrodynamic disk simulations with several different topologies for the initial magnetic field, we explore the degree to which the character of the flows around black holes depends on the initial topology. We find that while the qualitative properties of the accretion flow are nearly independent of field topology, jet launching is very sensitive to it; a sense of vertical field consistent for at least an inner disk inflow time is essential to the support of strong jets.
Time-Varying Systems

Section 1 provides a theory of reachability, observability, minimal realization and duality for time-varying linear systems, using only the basic language of linear algebra. Section 2 uses category theory to show that time-varying dynamics for adjoint processes in a category $\mathcal{K}$ may be defined as ad joint processes in a suitable new category $\mathcal{K}^{\bf z} $.
Computing at the junior/community college: programs and problems

This and the following papers contain different views of the same subject---"Computing Education at the Junior/Community College." It is a topic that has been long neglected, swept under the rug so to speak, in computing circles. It is about time that this topic was fully aired and its vital importance recognized by all engaged in computer education, business, industry and government. There are probably more students and more teachers involved in computer education at the junior/community colleges than at any other level of education.
The Long Journey from Ab Initio Calculations to Density Functional Theory for Nuclear Large Amplitude Collective Motion

At present there are two vastly different ab initio approaches to the description of the many-body dynamics: the density functional theory (DFT) and the functional integral (path integral) approaches. On one hand, if implemented exactly, the DFT approach can allow in principle the exact evaluation of arbitrary one-body densities. However, when applied to large amplitude collective motion (LACM), this approach needs to be extended in order to accommodate the phenomenon of surface-hopping, when adiabaticity is strongly violated and the description of a system using a single (generalized) Slater determinant is not valid anymore. The functional integral approach on the other hand does not appear to have such restrictions, but its implementation does not appear to be a straightforward endeavor. However, within a functional integral approach one seems to be able to evaluate in principle any kind of observable, such as the fragment mass and energy distributions in nuclear fission. These two radically different approaches can likely be brought together by formulating a stochastic time-dependent DFT approach to many-body dynamics.
A Structural and Dynamical Study of Late-Type, Edge-on Galaxies. II. Vertical Color Gradients and the Detection of Ubiquitous Thick Disks

We present an analysis of optical (B-R) and optical-infrared (R-Ks) color maps for 47 extremely late-type edge-on unwarped, bulgeless disk galaxies spanning a wide range of mass. The color maps show that the thin disks of these galaxies are embedded in a low surface brightness red envelope. This component is substantially thicker than the thin disk (a : b ~ 4 : 1 vs. >8 : 1), extends to at least 5 vertical disk scale heights above the galaxy midplane, and has a radial scale length that appears to be uncorrelated with that of the embedded thin disk. The color of the red envelope is similar from galaxy to galaxy, even when the thin disk is extremely blue, and is consistent with a relatively old (>6 Gyr) stellar population that is not particularly metal-poor. The color difference between the embedded thin disk and the red stellar envelope varies systematically with rotation speed, reflecting an increasing age difference between the thin and thick components in lower mass galaxies, driven primarily by changes in the age of the thin disk. The red stellar envelopes are similar to the thick disk of the Milky Way, having common surface brightnesses, spatial distributions, mean ages, and metallicities. We argue that the ubiquity of the red stellar envelopes implies that the formation of the thick disk is a nearly universal feature of disk formation and is not necessarily connected to the formation of a bulge. Our data suggest that the thick disk forms early (>6 Gyr ago), even within galaxies where the bulk of the stars formed very recently (<2 Gyr). We argue that several aspects of our data and the observed properties of the Milky Way thick disk argue in favor of a merger origin for the thick disk population. If so, then the age of the thick disk marks the end of the epoch of major merging, and the age difference between the younger thin disk and the older thick disk can become a strong constraint on cosmological constants and models of galaxy and/or structure formation.
An Alternative Approach to Algebro-Geometric Solutions of the AKNS Hierarchy

We develop an alternative systematic approach to the AKNS hierarchy based on elementary algebraic methods. In particular, we recursively construct Lax pairs for the entire AKNS hierarchy by introducing a fundamental polynomial formalism and establish the basic algebro-geometric setting including associated Burchnall–Chaundy curves, Baker–Akhiezer functions, trace formulas, Dubrovin-type equations for analogs of Dirichlet and Neumann divisors, and theta function representations for algebro-geometric solutions.
Effect of thermal anneal on growth behavior of laser-induced damage sites on the exit surface of fused silica

Thermal anneal is known to arrest the growth of laser-induced damage in optical materials. However, the response of the material which leads to this observed behavior is poorly understood. In this work, we investigate the effect of isothermal anneal at 1100°C for 12 hours on the growth rate of laser-induced damage sites in fused silica. Growth rate was significantly lower for annealed initiated damage sites than that for untreated sites. This decrease in growth rate was associated with the closure of small surface and subsurface cracks, suggesting that aggressive growth rate is due, at least in part, to subsurface fracture complexity.
Equations for the self-consistent field in random medium

An integral–differential equation is derived for the self-consistent (effective) field in the medium consisting of many small bodies randomly distributed in some region. Acoustic and electromagnetic fields are considered in such a medium. Each body has a characteristic dimension a⪡λ, where λ is the wavelength in the free space. The minimal distance d between any of the two bodies satisfies the condition d⪢a, but it may also satisfy the condition d⪡λ in acoustic scattering. In electromagnetic scattering our assumptions are a⪡λ and λ⪡d. Using Ramm's theory of wave scattering by small bodies of arbitrary shapes, the author derives an integral–differential equation for the self-consistent acoustic or electromagnetic fields in the above medium.
Linear dependency check in built-in test

Abstract Given a characteristic polynomial p ( x ) and a sampling polynomial with respect to p ( x ), a designer likes to know whether the sampling polynomial is a dependency polynomial. A dependency polynomial gives low fault coverage in the built-in self test. The tool LDC computes the residue combinations of the factors in the set polynomial and advises designers if the sampling polynomial covers all the testing space. When the sampling polynomial is a dependency polynomial, LDC will try to find one, if any, independent polynomial at a minimum cost. In cases of short test vectors LDC can exhaustively enumerate all independent polynomials for the designers to choose from. This paper reviews the basics of the linear dependency computation, explains the LDC capabilities and its usefulness, and discusses the computational issues of the problem.
Applying Asymptotic Approximations to the Full Two-Fluid Plasma System to Study Reduced Fluid Models

Summary form only given. Simulations are performed using the full two-fluid plasma system. The two-fluid plasma model is investigated for its capabilities of capturing physics that is lost with simpler fluid models such as magnetohydrodynamics (MHD). The regime in between the full two-fluid equation system and MHD is explored by the application of asymptotic approximations to the two-fluid system. These asymptotic approximations involve ignoring electron inertia, setting the speed of light to infinity and ensuring charge neutrality. Applying all three approximations together gives Hall MHD. The results obtained by applying the asymptotic approximations are compared to the two-fluid plasma model to determine what physics is lost by the application of each approximation. Simulations of electromagnetic plasma shock and collisionless reconnection will be presented to demonstrate the various physical effects in comparison to the results of the two-fluid model.
A Prospective Study of Physical Activity and Incident and Fatal Prostate Cancer

Background: Whether physical activity has benefits against prostate cancer incidence or progression is unclear. Therefore, we assessed physical activity in relation to prostate cancer incidence, mortality, and Gleason histologic grade. Methods: We used data from the Health Professionals Follow-up Study, a prospective cohort study, to determine the number of cases of incident, advanced (seminal vesicle invasion, metastasis, or fatal), fatal, and highgradeprostatecancerinacohortof47620USmalehealth professionals,followedupfromFebruary1,1986,toJanuary 31, 2000. Results: During 14 years of follow-up, we documented 2892 new cases of prostate cancer, including 482 advanced cases (280 of which were fatal). For total prostate cancer, no association was observed for total, vigorous, and nonvigorous physical activity. In men 65 years or older, we observed a lower risk in the highest categoryofvigorousactivityforadvanced(multivariablerelative risk, 0.33; 95% confidence interval, 0.17-0.62, for more than 29 vs 0 metabolic equivalent hours) and for fatal (relative risk, 0.26; 95% confidence interval, 0.110.66) prostate cancer. No associations were observed in younger men. Differential screening by prostatespecific antigen or a reduction in physical activity due to undiagnosed prostate cancer did not appear to account for the results. Among cases, men with high levels of physical activity were less likely to be diagnosed with poorly differentiated cancers (Gleason grade 7). Conclusion: Although the mechanisms are not yet understood,thesefindingssuggestthatregularvigorousactivity could slow the progression of prostate cancer and might be recommended to reduce mortality from prostate cancer, particularly given the many other documented benefits of exercise. Arch Intern Med. 2005;165:1005-1010
A novel superconducting glass state in disordered thin films in Clogston limit

A theory of mesoscopic fluctuations in disordered thin superconducting films in a parallel magnetic field is developed. At zero temperature and at a sufficiently strong magnetic field, the superconducting state undergoes a phase transition into a state characterized by superfluid densities of random signs, instead of a spin polarized disordered Fermi liquid phase. Consequently, in this regime, random supercurrents are spontaneously created in the ground state of the system, which belongs to the same universality class as the two dimensional XY spin glass. As the magnetic field increases further, mesoscopic pairing states are nucleated in an otherwise homogeneous spin polarized disordered Fermi liquid. The statistics of these pairing states is universal depending on the sheet conductance of the two-dimensional film.
Preparation of α-fluoro-α,β-unsaturated esters via two carbon homologation of esters☆

Abstract In the presence of diisobutyl aluminum hydride, esters react with an anion derived from (EtO) 2 P(O)CFHC(O)OEt to give the title compounds in good yields. The scope of this method and the factors which influence the stereochemistry of the products are discussed.
The least spanning area of a knot and the optimal bounding chain problem

Two fundamental objects in knot theory are the minimal genus surface and the least area surface bounded by a knot in a 3-dimensional manifold. When the knot is embedded in a general 3-manifold, the problems of finding these surfaces were shown to be NP-complete and NP-hard respectively. However, there is evidence that the special case when the ambient manifold is R^3, or more generally when the second homology is trivial, should be considerably more tractable. Indeed, we show here that a natural discrete version of the least area surface can be found in polynomial time. The precise setting is that the knot is a 1-dimensional subcomplex of a triangulation of the ambient 3-manifold. The main tool we use is a linear programming formulation of the Optimal Bounding Chain Problem (OBCP), where one is required to find the smallest norm chain with a given boundary. While the decision variant of OBCP is NP-complete in general, we give conditions under which it can be solved in polynomial time. We then show that the least area surface can be constructed from the optimal bounding chain using a standard desingularization argument from 3-dimensional topology.We also prove that the related Optimal Homologous Chain Problem is NP-complete for homology with integer coefficients, complementing the corresponding result of Chen and Freedman for mod 2 homology.
Chiral Lewis Acid Catalysis in Nitrile Oxide Cycloadditions

We describe examples of highly regio- and enantioselective nitrile oxide cycloadditions to unsaturated alkenes using substoichiometric amounts of a chiral Lewis acid. Pyrazolidinones proved to be effective achiral templates in the cycloadditions providing C-adducts typically in >30:1 selectivity and 80−99% ee. To avoid potential problems involving coordination of the Lewis acid by amine bases, we have devised a novel method for the generation of unstable nitrile oxides from hydroximinoyl chlorides using Amberlyst 21 as the base.
Competition of supermassive black holes and galactic spheroids in the destruction of globular clusters

The globular clusters that we observe in galaxies may be only a fraction of the initial population. Among the evolutionary influences on the population is the destruction of globular clusters by tidal forces as the cluster moves through the field of influence of a disk, a bulge, and/or a putative nuclear component (black hole). We have conducted a series of N-body simulations of globular clusters on bound and marginally bound orbits through poetentials that include black hole and speroidal components. The degree of concentration of the spheroidal component can have a considerable impact on the extent to which a globular cluster is disrupted. If half the mass of a 10(exp 10) solar mass spheroid is concentrated within 800 pc, then only black holes with masses greater than 10(exp 9) solar mass can have a significant tidal influence over that already exerted by the bulge. However, if the matter in the spheroidal component is not so strongly concentrated toward the center of the galaxy, a more modest central black hole (down to 10(exp 8) solar mass) could have a dominant influence on the globular cluster distribution, particularly if many of the clusters were initially on highly radial orbits. Our simulations show that the stars that are stripped from a globular cluster follow orbits with roughly the same eccentricity as the initial cluster orbit, spreading out along the orbit like a 'string of pearls.' Since only clusters on close to radial orbits will suffer substantial disruption, the population of stripped stars will be on orbits of high eccentricity.
The Casimir energy in a separable potential

Abstract The Casimir energy is the first-order-in-ℏ correction to the energy of a time-independent field configuration in a quantum field theory. We study the Casimir energy in a toy model, where the classical field is replaced by a separable potential. In this model the exact answer is trivial to compute, making it a good place to examine subtleties of the problem. We construct two traditional representations of the Casimir energy, one from the Green's function and the other from the phase shifts, and apply them to this case. We show that the two representations are correct and equivalent in this model. We study the convergence of the Born approximation to the Casimir energy and relate our findings to computational issues that arise in more realistic models.
Alkyl elimination from aldehydes on zinc oxide: Relevance to allylic oxidation pathways

Abstract The reactions of acetaldehyde, propionaldehyde, and acrolein on the (0001)-Zn polar surface of zinc oxide were investigated using temperature-programmed desorption and X-ray photoelectron spectroscopy. Oxidation of these aldehydes on the (0001)-Zn surface proceeded via two competing pathways: nucleophilic addition of lattice oxygen at the carbonyl carbon followed by hydride elimination to form the corresponding surface carboxylate species, and nucleophilic attack of lattice oxygen at the carbonyl carbon followed by alkyl elimination to form surface formate species. There was a strong temperature dependence of the selectivity toward these two competing pathways; low temperatures favored alkyl elimination, while high temperatures favored hydride elimination. The decomposition of the higher carboxylates resulted in the formation of both unsaturated carbonyl compounds and carbon oxides. The possible implications of these results for allylic oxidation reactions on metal oxide catalysts are discussed.
A universal cyclic division circuit

Recent innovations in circuit technology have allowed design alternatives that previously would have been economically unsound. LSI technology permits the use of generalized systems containing more logic than the specialized systems used in the past, implemented in unit logic, and at even lower cost. Five years ago an engineer would not have even considered using a cyclic redundancy checking circuit in the manner described here.
FEIGENBAUM ATTRACTOR AND THE GENERATION STRUCTURE OF PARTICLE PHYSICS

The standard model (SM) for high-energy physics describes fundamental interactions between subatomic particles down to a distance scale on the order of 10-18 m. Despite its widespread acceptance, SM operates with a large number of arbitrary parameters whose physical origin is presently unknown. Our work suggests that the generation structure of at least some SM parameters stems from the chaotic regime of renormalization group flow. Invoking the universal route to chaos in systems of nonlinear differential equations, we argue that the hierarchical pattern of parameters amounts to a series of scaling ratios depending on the Feigenbaum constant. Leading order predictions are shown to agree reasonably well with experimental data.
Side-Effects of Spironolactone Therapy in the Hirsute Woman

Spironolactone, an aldosterone antagonist with antiandrogenic activities, is often used to treat hirsute women. Several investigators have reported beneficial effects of such treatment, but the dosages used and side-effects encountered differ in their reports. To clarify this issue, 26 consecutive premenopausal women with idiopathic hirsutism were prospectively evaluated during spironolactone treatment. Sixteen women initially received 100 mg spironolactone twice daily on days 4-21 of their menstrual cycles. In 11 women (68%), the dosage had to be decreased or the medication discontinued due to side-effects. The major side-effect, metrorrhagia with 14-day cycles, occurred in 9 women (56%). This side-effect, while not dangerous, was intolerable to these women. In one woman, spironolactone was discontinued because of urticaria and in another because of scalp hair loss. Ten women initially received 50 mg spironolactone twice daily on days 4-21 of their menstrual cycles. Two developed metrorrhagia, but no other side-effects were noted. Because of the incidence of metrorrhagia at higher dosages, we recommend that spironolactone be administered cyclically at a starting dosage of 50 mg twice daily on days 4-21 of the menstrual cycle. Alternatively, one may consider adding cyclical estrogen/progesterone therapy to continuous spironolactone therapy.
New Families of Hygrothermally Stable Composite Laminates with Optimal Extension-Twist Coupling

The necessary and sufficient conditions for hygrothermal stability of laminated composites are presented. A thorough survey of hygrothermally stable families is performed to identify stacking sequences that produce maximum extension-twist coupling. This is achieved through a constrained optimization routine, where the objective function is derived from the constitutive law given in classical lamination theory and the constraints are the necessary conditions for hygrothermal stability. A representative sample of these optimized laminates are constructed and tested to demonstrate significant improvement in coupling over the previously known optima. Comparisons are made with a nonlinear model and finite element analysis. An investigation of the robustness of the optimal stacking sequences to errors in ply angle typical of hand-layup manufacturing is presented.
Concise asymmetric synthesis of fully substituted isoxazoline-N-oxide through Lewis base catalyzed nitroalkene activation.

The synthesis of optically active isoxazoline N-oxides is based on the pyrrolidine-catalyzed reaction of optically active ketone ylide (I) with a nitroalkene and an aldehyde.
Infrared flow visualization of V/STOL aircraft

During low altitude operations of vertical/short takeoff and landing (V/STOVL) aircraft complex aeropropulsive flowfields are produced by the strong interactions between the engine exhaust jet or propeller wash and the runway and aircraft surfaces. Measurement of these unsteady 3 dimensional flowfields has not proven practical with conventional measurement techniques. It has been demonstrated that modern infrared imaging systems provide a practical means of obtaining flow visualization images of these complex aeropropulsive flowfields. Infrared images obtained with a dual wavelength scanning system are presented which provide detailed information on the flowfields about the NASA Ames XV-15 tiltrotor aircraft, the E-7 STOVL research model and the NASA Ames YAV-8B Harrier aircraft. It was found that the use of a dual wavelength infrared system provides valuable information about both the engine exhaust flowfield and the resulting heating of aircraft and runway surfaces.
Effect of pore structure on miscible displacement in laboratory cores

Observations of pore structure in thin-sections are related to the performance of stable, first-contact-miscible displacements in reservoir cores and then to simulations of displacement performance of CO/sub 2/ corefloods. Results of effluent composition measurements are reported for miscible displacements in seven core samples - three sandstones and four San Andres carbonates from west Texas or eastern New Mexico. Those displacements are interpreted by fitting the measured effluent compositions to the Coats-Smith (C-S) model, which represents the flow as occurring in flowing and stagnant fractions with mass transfer between them. Observations of thin-sections, including measurements of pore-size distributions and a simple measurement of spatial correlation of pore sizes, are also reported. Comparison of displacement results and thin-section data indicates that wide pore-size distributions and preferential flow paths are characterized in the C-S model by high dispersion coefficients and low flowing fractions. Simulations of the interactions of phase behavior and flow in nonuniform pore structures indicate that wide pore-size distributions and preferential flow paths can significantly increase residual oil saturations (ROS's) in CO/sub 2/ floods over those for uniform pore structures. Thus, heterogeneities observable at the scale of a thin-section have significant effects in laboratory core but much smaller effects in displacements more » at field scale. Large-scale heterogeneities present in field floods, however, probably cause similar increases in residual saturation in some fields. « less
PRODUCTION OF MAGNETIC ENERGY BY MACROSCOPIC TURBULENCE IN GRB AFTERGLOWS

Afterglows of gamma-ray bursts are believed to require magneticfields much stronger than that of the compressed preshockmedium.Asanalternativetomicroscopicplasmainstabilities,weproposeamplificationofthefieldbymacroscopicturbulenceexcitedbytheinteractionoftheshockwithaclumpypreshockmedium,forexample,astellarwind. Using a recently developed formalism for localized perturbations to an ultrarelativistic shock, we derive constraints on thelengthscale,amplitude,andvolumefillingfactorof densityclumpsrequiredtoproduceagivenmagneticenergyfractionwithintheexpansiontimeoftheshock,assumingthattheenergyinthefieldachievesequipartionwiththeturbulence. StrongerandsmallerscaleinhomogeneitiesarerequiredforlargershockLorentzfactors.Hence,itislikelythatthe magnetic energy fraction evolves as the shock slows. This could be detected by monitoring the synchrotron cooling frequency if the radial density profile ahead of the shock, smoothed over clumps, is known. Subject headingg gamma rays: bursts — hydrodynamics — magnetic fields — shock waves — turbulence
Definitional Excursions: The Meanings of Modern/Modernity/Modernism

What is modernity? What is or was modernism? Why is the energetic, expanding, multidisciplinary field of modernist studies so filled with contestation over the very ground of study? Definitional activities are fictionalizing processes, however much they sound like rational categorization. As such, I will begin with three stories, allegorized but rooted in my own experience in an evolving field.1
Semiparametric instrumental variable estimation of simultaneous equation sample selection models

The identification and estimation of a semiparametric simultaneous equation model with selectivity have been considered. The identification of structural parameters from reduced form parameters in the semiparametric model requires stronger conditions than the usual rank condition in the classical simultaneous equation model or the parametric simultaneous equation sample selection model with normal disturbances. The necessary order condition for identification in the semiparametric model corresponds to the overidentification condition in the classical model. Semiparametric two-stage estimation methods which generalize the two-stage least squares method and the generalized two-stage least squares method for the parametric model are introduced. The semiparametric generalized two-stage least squares estimator is shown to be asymptotically efficient in a class of semiparametric instrumental variable estimators.
Accretion onto Seed Black Holes in the First Galaxies

The validity of the hypothesis that the massive black holes in high redshift quasars grew from stellar-sized "seeds" is contingent on a seed's ability to double its mass every few 10 million years. This requires that the seed accrete at approximately the Eddington-limited rate. In the specific case of radiatively efficient quasi-radial accretion in a metal-poor protogalactic medium, for which the Bondi accretion rate is often prescribed in cosmological simulations of massive black hole formation, we examine the effects of the radiation emitted near the black hole's event horizon on the structure of the surrounding gas flow. We find that photoheating and radiation pressure from photoionization significantly reduce the steady-state accretion rate and potentially render the quasi-radial accretion flow unsteady and inefficient. The time-averaged accretion rate is always a small fraction of the "Bondi" accretion rate calculated ignoring radiative feedback. The pressure of Lyα photons trapped near the H II region surrounding the black hole may further attenuate the inflow. These results suggest that an alternative to quasi-radial, radiatively efficient Bondi-like accretion should be sought to explain the rapid growth of quasar-progenitor seed black holes.
Cosmic Infrared Background and Early Stellar Populations

Cosmic infrared background (CIB) contains information about galaxy luminosities over the entire history of the Universe and can be a powerful diagnostic of the early populations otherwise inaccessible to telescopic studies. Its measurements are very difficult because of the strong IR foregrounds from the Solar system and the Galaxy. Nevertheless, substantial recent progress in measuring the CIB and its structure has been made. The measurements now allow to set significant constraints on early galaxy evolution and, perhaps, even detect the elusive Population III era. We discuss briefly the theory behind the CIB, review the latest measurements of the CIB and its structure, and discuss their implications for detecting and/or constraining the first stars and their epochs.
Do we follow others when we should outside the lab? Evidence from the AP Top 25

We use data from the Associated Press college American football poll to analyze two types of ex-post optimality of social learning in a non-lab setting. The poll is a weekly subjective ranking of the top 25 teams, voted on by over 60 sports journalists. Voters potentially can learn from their peers by observing the aggregate ranks before updating their individual ranks. Our results indicate that, while voters do learn from their peers to some extent, the informativeness of peer ranks appears to be under-valued.
Application of a periodic lattice filter for identifying flexible structures

Lattice filters have properties which make them attractive for the application to the identification of the parameters of flexible structures. Here, the problem of both order and parameter estimation is addressed, where the numerical difficulties of an embedded lattice filter are avoided by applying a periodic lattice filter. With this formulation, it is quite natural to estimate system order by applying Akaike's (1976) information criterion to each channel of the periodic lattice filter. Several examples including nonstationary cases are simulated to demonstrate these facts.
Distortion-Induced Vibration in Fan and Compressor Blading

System of the F-104 Aircraft," WADC TR-1756, 1959, Wright Air Development Center, Wright-Patterson Air Force Base, Ohio. Rudinger, G., Wave Diagrams for Non-Steady Flow In Ducts, Van Nostrand, New York, 1955. ^Marshall, F. L., "Prediction of Inlet Overpressures Resulting From Engine Surge," Journal of Aircraft, Vol. 10, May 1974, pp. 274-278. Kurkov, A. P., Soeder, R. H., and Moss, J. E., "Investigation of the Stall-Induced Shock Wave (Hammershock) at the Inlet to the Engine," TMX-71594, Sept. 1974, NASA. Martin, A. W., "Propulsion System Dynamic Simulation Theory and Equations," CR-928, April 1967, NASA. Martin, A. W., and Wong, H. W., "Propulsion System Dynamic Simulation Users Manual," CR-73113, April 1967, NASA. Martin, A. W., and Kostin, L. C., "Propulsion System Dynamic Test Results," CR-73114, April 1967, NASA. Martin, A. W., "Propulsion System Dynamic Simulation Data," CR-73115, April 1967, NASA. Martin, A. W. and Beaulieu, W. D., "XB-70 Flight Test Data Comparison With Simulation Predictions of Inlet Unstart and Buzz," CR-1631, June 1969, NASA. Johnson, R. H., "B-l Hammershock Estimates," NA 70-38, Aug. 1970, Rockwell International, Los Angeles, Calif. Amin, N. F. and Hall, G. R., "Supersonic Inlet Investigation, Air Induction System Dynamic Simulation Model," AFFDL-TR-121, Vol II, Sept. 1971, Air Force Flight Dynamics Lab., Wright-Patterson Air Force Base, Ohio. Choby, D. A., Burstadt, P. L., and Calogeras, J. E., "Unstart and Stall Interactions Between a Turbojet Engine and an Axisymmetric Inlet With 60-Percent Internal-Area Contraction," TMX-2192, March 1971, NASA. Nugent, J. and Holtzman, J., "Flight-Measured Inlet Pressure Transients Accompanying Engine Compressor Surges on the F-111A Airplane," TND-7696, June 1974, NASA. Barnard, J. D. and Evans, P. J., "Air Induction System EngineStall Loads," Proceedings of Third Structural Loads Workshop for Preliminary Aerospace Design Projects, Aeronautical Systems Division, Wright-Patterson Air Force Base, Sept., 1970, pp.89-127. Randall, L. M., et al., Rockwell Propulsion System Aerodynamics, "B-l Full Scale Inlet-Engine Compatibility Test, AEDC TF 329 and SF 166, Vol. I, Preliminary Summary," NA-74-375, Aug. 1974, Arnold Engineering Development Center, Tullahoma, Tenn.
The Determinants of US Public Opinion Towards Democracy Promotion

In this paper, I evaluate two competing perspectives regarding what underlies the public’s support for democracy promotion—a democratic values-based perspective positing that the public’s support for democracy promotion is based on a principled desire to spread American values, beliefs, and ideologies to other countries, and a national interests-based perspective claiming that it is based on a rational desire of Americans to advance the US’ political and economic interests abroad. Using a survey experiment, I find that, in general, Americans are not driven by either democratic values or national interests to support democracy promotion even though they believe that democracy promotion is in the interests of both the recipient country and the United States. Only a subset of the population is motivated to support democracy promotion for the sake of democratic values. This subset of the population is driven by cosmopolitanism—that is, a sense of concern for the welfare of those living in other countries and a sense of moral responsibility to promote democracy abroad derived from the US’ position as a world leader, not national pride.
Operation and performance of a double-alkali scrubber

Santa Fe Energy Co. (SFEC) installed a double-alkali sulfur dioxide absorber at its Kern River field near Bakersfield, CA. The flue gas desulfurization (FGD) system is designed to remove 95% of the sulfur dioxide from the exhaust of eight oil-fired steam generators when 1.5 wt% sulfur fuel oil is burned. The chemistry of the double-alkali process and the results of compliance and performance emissions testing are presented. Sulfur dioxide emission results are analyzed. Performance tests showed that total outlet sulfur dioxide emissions were 28.7 lbm/hr (0.00363 kg/s). If offset emissions are included, the net sulfur dioxide emissions were 0.22 lbm/hr (0.00003 kg/s).
Estimating the Deployment Pressure in Pumpkin Balloons

A vexing conundrum that has hindered the development of a high-altitude heavy-lift pumpkin balloon system is the system’s ability to reliably deploy into the desired symmetric shape. With design strategies honed by empirical results from inflation tests in 2007 using 27-m-diam 200-gore pumpkin balloons, NASA’s Balloon Program Office executed successful pumpkin deployments in 2008: Flight 586-NT, a 2 million cubic foot 200-gore design, and Flight 591-NT, a 6 million ft 200-gore design. Earlier stability analysis of strained symmetric float shapes yielded partial information regarding deployment. Balloons that were found to have a large number of unstable modes at float conditions were found also to have deployment problems. The question remained, what was the minimum pressure at which a pumpkin balloon would deploy into a cyclically symmetric shape (not necessarily the fully developed one)? Careful examination of a family of axisymmetric ascent shapes revealed a correlation between differential pressure and the number of unstable modes. In this paper, criteria that can be used to estimate the deployment pressure is presented. To bound the problem, fixed-, constrained-, and free-boundary conditions are considered for the top endplate fitting. It was found that the stability results using the fixed and constrained conditions are nearly identical, and so the strategy for estimating the deployment pressure, called the deployment pathway portrait, is as follows. The deployment pressurePDep is defined as the smallest nadir pressurewhere the topfree boundary condition yields two unstable modes and the top-fixed boundary condition yields no unstable modes. The approach is validated by comparing analytical predictions of deployment pressures based on the deployment pathway portrait with the deployment pressures that were recorded during the inflation tests in 2007: Flight 586-NT and Flight 591-NT. Very good agreement between the observed deployment pressures and the analytical predictions was found. This is the first analytical-based approach for estimating the deployment pressure.
Spatial Competition between Parking Garages and Downtown Parking Policy

Abstract This paper looks at optimal parking policy in dense urban districts (“downtown”), where spatial competition between parking garages is a key feature, from the perspective of economic theory. The paper has four parts. The first looks at the “parking garage operator's problem”. The second derives equilibrium in the parking garage market when there is no on-street parking, compares the equilibrium to the social optimum, and examines optimal parking policy in this context. Since parking garage operators have market power, the spatial competition equilibrium is generally inefficient, and parking policy can be used to mitigate the distortion. The third adds on-street parking and considers how its underpricing affects second-best parking policy. The fourth adds mass transit, and considers how economies of scale in mass transit interact with minimum and maximum off-street parking standards. Preliminary draft: Please do not cite or quote without the permission of the author.
BRANE COSMOLOGY WITH NON-STATIC BULK

We study the brane world motion in non-static bulk by generalizing the second Randall-Sundrum scenario Explicitly, we take the bulk to be a Vaidya-AdS metric, which describes the gravitational collapse of a spherically symmetric null dust fluid in Anti-de Sitter spacetime. We point out that during an inflationary phase on the brane, black holes will tend to be thermally nucleated in the bulk We analyze the thermodynamical properties of this brane-world. We point out that during an inflationary phase on the brane, black holes will tend to be thermally nucleated in the bulk. Thermal equilibrium of the system is discussed. We calculate the late time behavior of this system, including 1-loop effects. We argue that at late times a sufficiently large black hole will relax to a point of thermal equilibrium with the brane-world environment. This result has interesting implications for early-universe cosmology.
A review of early-type close binary systems

This is a review of close binary systems with very early spectral types (B, O, Of, and WR stars). We limit our selection to systems with Roche model photometric solution only. There are 10 contact systems known at present. Three of them (V701 Sco, BH Cen, and RZ Pyx) are located in the vicinity of the zero-age contact (ZC) according to a Spectral Type — Period diagram. Only the first two systems have absolute dimensions available. Both of these fall into the ZC zone in the logP — log m diagram and the log m — log R diagram. The system TU Mus was thought to be a ZC system is located in the evolved contact zone (EC) in the above diagrams. Both V701 Sco and BH Cen were thought to be having mass ratios about unity. With the much improved light curves of BH Cen and new analysis the mass ratio has been revised to 0.84! This result may favor Shu’s model for early-type zero-age contact systems. The evolved systems might be undergone Case A mass exchange except for two systems (V729 Cyg and RY Sct) which might be from Case B. The systems V367 Cyg was classified by Plavec as a W Ser system may be a evolved contact system.
Hypercube algorithms for operations on quadtrees

Abstract This paper describes parallel algorithms for the following operations on quadtrees—boolean operations (union, intersection, complement), collapsing a quadtree, and neighbor finding in an image represented by a quadtree. The architecture assumed in this paper is a hypercube with one processing element (PE) per hypercube node. It is assumed that the architecture is SIMD, i.e. all PEs work under the control of a single control unit.
Reconstructing the peculiar velocity of the Local Group with modified gravity and 2MASS

The peculiar velocity of the Local Group (LG), reconstructed from inhomogeneities in the local density field, differs in direction and magnitude from the velocity inferred from the cosmic microwave background (CMB) dipole. We investigate whether generalized theories of gravity, which predict a modified growth of perturbations, are able to alleviate this discrepancy. We introduce a general formalism for calculating the real-space peculiar-velocity field for modified gravity and theories with interactions in the dark sector. For different classes of theories - scalar-tensor and higher dimensional gravity - we reconstruct the LG peculiar velocity using groups of galaxies identified in the 2MASS Redshift Survey. We show that, for realistic parameters, the change in direction, with respect to the standard general relativity result, is less than 2°; this is significantly smaller than the ∼40° angular discrepancy between the reconstructed LG velocity and the dipole in the CMB.
Triazole-based monophosphines for Suzuki-Miyaura coupling and amination reactions of aryl chlorides.

A new class of triazole-based monophosphine 1 (ClickPhos) has been prepared via efficient 1,3-dipolar cycloadditions of readily available azides and acetylenes. Palladium complexes derived from these ligands provide highly active catalysts for Suzuki−Miyaura coupling and amination reactions of aryl chlorides.
Superconductive excitations and the infrared vibronic spectra of BSCCO

The oxygen dopant concentration dependence of the “quasiparticle” feature at 600–750 cm–1 of the infrared spectrum of Bi2Sr2CaCu2O8+δ (BSCCO), lying near but above the top of the host phonon spectrum at 600 cm–1, is strongly correlated with superconductivity. Using parameter-free topological methods, theory assigns this feature to split apical oxygen interstitials. It explains both the qualitative similarities and the quantitative differences between “quasiparticle” features identified in infrared and photoemission data, as well as identifying new features in the infrared spectra. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
An improved time-space lower bound for tautologies

We show that for all reals c and d such that c 2 d<4 there exists a positive real e such that tautologies of length n cannot be decided by both a nondeterministic algorithm that runs in time n c , and a nondeterministic algorithm that runs in time n d and space n e . In particular, for every $d<\sqrt[3]{4}$ there exists a positive e such that tautologies cannot be decided by a nondeterministic algorithm that runs in time n d and space n e .
Proposal for a constant cosmological constant

Abstract It is proposed that the apparent positive acceleration of the cosmological scale factor is due to the vacuum energy of an incomplete chiral phase transition in a hidden SU(2) sector. Constraints from primordial nucleosynthesis imply that the present metastable phase is in a substantially supercooled state. It is argued that massless chiral condensates can substantially enhance the possibility of supercooling, and a linear sigma model exhibiting scale invariance broken only at the quantum level is shown to accommodate the required supercooling with a reasonable choice of quartic couplings. The extensive supercooling can in principle be confirmed or rejected on the basis of interface tension measurements in lattice simulations with dynamical fermions.
GEOMETRY OF WACHSPRESS SURFACES

Let Pd be a convex polygon with d vertices. The associated Wach- spress surface Wd is a fundamental object in approximation theory, defined as the image of the rational map P 2 wd ! P d 1 , determined by the Wachspress barycentric coordinates for Pd. We show wd is a regular map on a blowup Xd of P 2 and if d > 4 is given by a very ample divisor on Xd, so has a smooth image Wd. We determine generators for the ideal of Wd, and prove that in graded lex order, the initial ideal of IWd is given by a Stanley-Reisner ideal. As a consequence, we show that the associated surface is arithmetically Cohen-Macaulay, of Castelnuovo-Mumford regularity two, and determine all the graded betti numbers of IWd .
An economic model for pricing tiered network services

We consider networks offering tiered services and corresponding price structures, a model that has become prevalent in practice. We develop an economic model for such networks and make contributions in two important areas. First, we formulate the problem of selecting the service tiers from three perspectives: one that considers the users’ interests only, one that considers only the service provider’s interests, and one that considers both simultaneously, i.e., the interests of society as a whole. We also present an approximate yet accurate and efficient solution approach for tackling these nonlinear programming problems. Given the set of (near-) optimal service tiers, we then employ game-theoretic techniques to find an optimal price for each service tier that strikes a balance between the conflicting objectives of users and service provider. This work provides a theoretical framework for reasoning about and pricing Internet tiered services, as well as a practical toolset for network providers to develop customized menus of service offerings. Our results also indicate that tiering solutions currently adopted by ISPs perform poorly both for the providers and society overall.
Optimal asymmetric strategies in research joint ventures

Abstract This paper identifies an overlooked implication of models of research joint ventures initiated by d'Aspremont and Jacquemin (1988) . Even though the aggregate R&D cost of identical firms in a research joint venture would be lowest if they invested equally to reduce subsequent production costs, nonetheless members may often enlarge their overall joint profit by making unequal investments. Such a strategy raises costs in the investment stage but may create more than offsetting benefits in the production stage since industry profits are larger there when the firms are of unequal size. When the consideration leading to asymmetry prevails, we find that, in contrast to previous work, a research joint venture can raise welfare even when there are no spillovers.
Two avenues to self-interaction correction within Kohn—Sham theory: unitary invariance is the shortcut

The most widely used density functionals for the exchange-correlation energy are inexact for one-electron systems. Their self-interaction errors can be severe in some applications. The problem is not only to correct the self-interaction error, but to do so in a way that will not violate size-consistency and will not go outside the standard Kohn-Sham density functional theory. The solution via the optimized effective potential (OEP) method will be discussed, first for the Perdew-Zunger self-interaction correction (whose performance for molecules is briefly summarized) and then for the more modern self-interaction corrections based upon unitarily invariant indicators of iso-orbital regions. For the latter approaches, the OEP construction is greatly simplified. The kinetic-energy-based iso-orbital indicator TW σ(r)/Tσ(r) will be discussed and plotted, along with an alternative exchange-based indicator.