cssi/SciSciGPT-SciSciNet huggingface dataset:
Energy Conservation, Efficiency and Substitution

The US has failed to make a serious reduction in oil consumption because, unlike other western countries, the US has not made a national commitment to develop alternative energy sources. Energy costs, as a result, are no longer in equilibrium with the gross national product. A proposal to replace oil with electricity in five end-use applications is possible with present technology and, in most cases, with available products. The suggested end uses are residential and commercial space conditioning, low-temperature industrial and commercial heat, high-temperature industrial direct heat, intracity passenger and freight transport by bus and van, and high-density rail transport. Other opportunities are substituting electricity or coal for gas and repowering oil-fired power plants to burn coal. Low-cost and cost-effective options should be taken first and should concentrate on replacing oil and on the costs of changing the energy systems. (DCK)
Expansion of the Supergranular Magnetic Network through the Solar Atmosphere

The solar magnetic field has its footpoints in the photosphere, extends through the chromosphere, and is thought to expand through the transition region and into the corona. It is organized by fluid motions to form strong flux concentrations within the boundaries of the supergranular convection cells. These boundaries are the network lanes observed in line emission, and they display increasing width with height through the solar atmosphere. The network field concentrations are surrounded by a mixed-polarity internetwork magnetic field on the scale of granulation. We use a potential magnetic field extrapolation of synthetic photospheric magnetograms to study the magnetic network topology and the effects of a mixed-polarity background field on the network expansion with height through the solar atmosphere. We find that the expansion of the network boundary with height deviates significantly from the funnel expansion model. Moreover, we find that the background magnetic field has a considerable effect on the filling factor of the network area with height, even though the background flux is strictly equal to zero.
Effect of Uncertainty in Blowing Ratio on Film Cooling Effectiveness

In this study, the effect of randomness of blowing ratio on film cooling performance is investigated by combining direct numerical simulations with a stochastic collocation approach. The geometry includes a 35-deg inclined jet with a plenum attached to it. The blowing ratio variations are assumed to have a truncated Gaussian distribution with mean of 0.3 and the standard variation of approximately 0.1. The parametric space is discretized using multi-element general polynomial chaos (ME-gPC) with five elements where general polynomial chaos of order 3 is used in each element. Direct numerical simulations were carried out using spectral element method to sample the governing equations in space and time. The probability density function of the film cooling effectiveness was obtained and the standard deviation of the adiabatic film cooling effectiveness on the blade surface was calculated. A maximum of 20% of variation in film cooling effectiveness was observed at 2.2 jet-diameter distance downstream of the exit hole. The spatially-averaged adiabatic film cooling effectiveness was 0.23 ± 0.02. The calculation of all the statistical properties were carried out as off-line post processing. A fast convergence of the polynomial expansion in the random space is observed which shows that the computational strategy is very cost-effective.
Uniqueness of the maximum likelihood estimator for $k$-monotone densities

We prove uniqueness of the maximum likelihood estimator for the class of k monotone densities. AMS 2000 subject classications: Primary 62G07.
A Visual Study of Turbine Blade Pressure-Side Boundary Layers

Boundary layer characteristics on the pressure-side of a turbine airfoil were investigated experimentally in a three-blade cascade tunnel. The blades had a chord length of 21 in. to facilitate flow visualization and high-speed photography. The investigation revealed the existence of the Gortler’s vortices appearing in spurts in regions of severe curvature. In the trailing edge region, Karman vortices were detected and found to interact strongly with the Gortler’s vortices convected thereto.
THE FORMATION OF SUPERMASSIVE BLACK HOLES FROM LOW-MASS POP III SEEDS

The existence of 109 M ☉ black holes (BHs) in massive galaxies by z ~ 7 is one of the great unsolved mysteries in cosmological structure formation. One theory argues that they originate from the BHs of Pop III stars at z ~ 20 and then accrete at the Eddington limit down to the epoch of reionization, which requires that they have constant access to rich supplies of fuel. Because early numerical simulations suggested that Pop III stars were 100 M ☉, the supermassive black hole (SMBH) seeds considered up to now were 100-300 M ☉. However, there is a growing numerical and observational consensus that some Pop III stars were tens of solar masses, not hundreds, and that 20-40 M ☉ BHs may have been much more plentiful at high redshift. However, we find that natal kicks imparted to 20-40 M ☉ Pop III BHs during formation eject them from their halos and hence their fuel supply, precluding them from Eddington-limit growth. Consequently, SMBHs are far less likely to form from low-mass Pop III stars than from very massive ones.
Emergence of magnetism in graphene materials and nanostructures

Magnetic materials and nanostructures based on carbon offer unique opportunities for future technological applications such as spintronics. This paper reviews graphene-derived systems in which magnetic correlations emerge as a result of reduced dimensions, disorder and other possible scenarios. In particular, zero-dimensional graphene nanofragments, one-dimensional graphene nanoribbons and defect-induced magnetism in graphene and graphite are covered. Possible physical mechanisms of the emergence of magnetism in these systems are illustrated with the help of computational examples based on simple model Hamiltonians. In addition, this review covers spin-transport properties, proposed designs of graphene-based spintronic devices, magnetic ordering at finite temperatures as well as the most recent experimental achievements.
Genericity, the Arzhantseva-Ol’shanskii method and the isomorphism problem for one-relator groups

We show that the isomorphism problem is solvable in at most exponential time for a class of one-relator groups which is exponentially generic in the sense of Ol’shanskii. This is obtained by applying the Arzhantseva-Ol’shanskii graph minimization method to prove the general result that for fixed integers m≥2 and n≥1 there is an exponentially generic class of non-free m-generator n-relator groups with the property that there is only one Nielsen equivalence class of m-tuples which generate a non-free subgroup. In particular, every m-generated subgroup in such a generic group G is either free or is equal to G itself and such groups are thus co-Hopfian. These results are obtained by elementary methods without using the deep results of Sela about co-Hopficity and the isomorphism problem for torsion-free hyperbolic groups.
Dividend clienteles: a global investigation

We compare the cross-sectional variation in the dividend payout policies of companies across 32 countries. Beyond the impact of firm-specific accounting and financial variables, this study investigates how the country level variations: shareholder demand due to demographic variations and consumption needs, agency problems manifested in the extent of minority shareholder protection and business disclosures, and market quality in terms of transparency and liquidity; affect the dividend payout policies. We find that firms have generous dividend payout policies when diverse shareholder demands are strong, extents of business disclosures and legal protections are weak, and the market qualities are poor. The empirical evidence supports the presence of strong dividend clienteles in a global setting.
On the relationship of gravitational constants in KK reduction

In this short note, we try to clarify a seemly trivial but often confusing question in relating a higher-dimensional physical gravitational constant to its lower-dimensional correspondence in Kaluza-Klein reduction. In particular, we re-derive the low-energy M-theory gravitational constant in terms of type-IIA string coupling gs and constant α' through the metric relation between the two theories.
Processing and preparation costs for rice and coarse grains in urban Mali: Subjecting an Ipse Dixit to empirical scrutiny☆

Abstract This article uses household survey data from Bamako, Mali, to address three questions, important in the policy debate concerning the determinants of the substitution from coarse grains to rice in West African diets, and policy options. The questions are: (1) what are the relative costs of rice and coarse grain-based dishes, with and without complementary sauce costs? (2) What are the shares in total cost of individual processing and preparation stages? (3) Are pre-processed coarse grains (e.g. dehulled grain or flour) cheaper to consume than coarse grains processed in the household? Contrary to prevailing opinion, the paper shows that despite higher processing costs, coarse grain-based dishes are cheaper than rice-based dishes. The main contributory factors to the higher cost of rice-based dishes are sauce cost, cereal cost and preparation (cooking and sauce preparation) time. The result holds true over a wide range of rice and coarse grain prices, and opportunity costs of women's time, suggesting that the finding applies more generally to the urban Sahel and not just Bamako. Moreover, coarse grain-based dishes need not take longer to process and prepare than rice-based dishes if the dehulling step is mechanized. However, pre-processed coarse grains are not competitive with household processing given present technology and opportunity costs of women's time. Nor will coarse grains be able to retain the extent of their cost advantage over rice as incomes and labor opportunity costs rise without improvements in the efficiency of processing services.
Neural substrates of perceptual integration during bistable object perception.

The way we perceive an object depends both on feedforward, bottom-up processing of its physical stimulus properties and on top-down factors such as attention, context, expectation, and task relevance. Here we compared neural activity elicited by varying perceptions of the same physical image—a bistable moving image in which perception spontaneously alternates between dissociated fragments and a single, unified object. A time-frequency analysis of EEG changes associated with the perceptual switch from object to fragment and vice versa revealed a greater decrease in alpha (8–12 Hz) accompanying the switch to object percept than to fragment percept. Recordings of event-related potentials elicited by irrelevant probes superimposed on the moving image revealed an enhanced positivity between 184 and 212 ms when the probes were contained within the boundaries of the perceived unitary object. The topography of the positivity (P2) in this latency range elicited by probes during object perception was distinct from the topography elicited by probes during fragment perception, suggesting that the neural processing of probes differed as a function of perceptual state. Two source localization algorithms estimated the neural generator of this object-related difference to lie in the lateral occipital cortex, a region long associated with object perception. These data suggest that perceived objects attract attention, incorporate visual elements occurring within their boundaries into unified object representations, and enhance the visual processing of elements occurring within their boundaries. Importantly, the perceived object in this case emerged as a function of the fluctuating perceptual state of the viewer.
Self-Intersection Numbers of Length-Equivalent Curves on Surfaces

Two free homotopy classes of closed curves in an orientable surface with negative Euler characteristic are said to be length-equivalent if the lengths of the geodesics in the two classes are equal for every hyperbolic structure on the surface. We show that there are elements in the free group on two generators that are length-equivalent but have different self-intersection numbers. This applies to both the punctured torus and the pair of pants. Our result answers open questions about length-equivalence classes and raises new ones.
QCD at finite baryon density: nucleon droplets and color superconductivity

Abstract We use a variational procedure to study finite density QCD in an approximation in which the interaction between quarks is modelled by that induced by instantons. We find that uniform states with conventional chiral symmetry breaking have negative pressure with respect to empty space at all but the lowest densities, and are therefore unstable. This is a precisely defined phenomenon which motivates the basic picture of hadrons assumed in the MIT bag model, with nucleons as droplets of chiral symmetry restored phase. At all densities high enough that the chirally symmetric phase fills space, we find that color symmetry is broken by the formation of a 〈 qq 〉 condensate of quark Cooper pairs. A plausible ordering scheme leads to a substantial gap in a Lorentz scalar channel involving quarks of two colors, and a much smaller gap in an axial vector channel involving quarks of the third color.
Multi-resource investment strategies: Operational hedging under demand uncertainty

Abstract Consider a firm that markets multiple products, each manufactured using several resources representing various types of capital and labor, and a linear production technology. The firm faces uncertain product demand and has the option to dynamically readjust its resource investment levels, thereby changing the capacities of its linear manufacturing process. The cost to adjust a resource level either up or down is assumed to be linear. The model developed here explicitly incorporates both capacity investment decisions and production decisions, and is general enough to include reversible and irreversible investment. The product demand vectors for successive periods are assumed to be independent and identically distributed. The optimal investment strategy is determined with a multi-dimensional newsvendor model using demand distributions, a technology matrix, prices (product contribution margins), and marginal investment costs. Our analysis highlights an important conceptual distinction between deterministic and stochastic environments: the optimal investment strategy in our stochastic model typically involves some degree of capacity imbalance which can never be optimal when demand is known.
Near-zero modes in superconducting graphene

Vortices in the simplest superconducting state of graphene contain very-low-energy excitations whose existence is connected to an index theorem that applies strictly to an approximate form of the relevant Bogoliubov–de Gennes equations. When Zeeman interactions are taken into account, the zero modes required by the index theorem are (slightly) displaced. Thus, the vortices acquire internal structure, which plausibly supports interesting dynamical phenomena.
The Strategic Usefulness of Management Information as Perceived by Middle Managers

The study sought to investigate the impact of the contextual variables of decentralization and environmental uncertainty on the strategic usefulness of management information as perceived by middle managers of an overseas subsidiary of a large, diversified multinational corporation. Management information was expressed in terms of the characteristics of aggregation, scope, and timeliness. Factor analysis was used to verify these dimensions. Data were collected through the use of a questionnaire. Three hypothesized relationships between the contextual variables and the information characteristics were tested through multiple regression analysis. The results indicated that there was a significant relationship between the management information characteristics and perceived environmental uncertainty. Two of the information characteristics-scope and timeliness-showed no significant relationship with decentralization. Aggregation of information, however, only showed a relationship with decentralization through...
Evaluating public transit modal shift dynamics in response to bikesharing: a tale of two U.S. cities

Public bikesharing—the shared use of a bicycle fleet—has recently emerged in major North American cities. Bikesharing has been found to decrease driving and increase bicycling. But shifts in public transit have been mixed. The authors evaluate survey data from two U.S. cities to explore who is shifting toward and away from public transit as a result of bikesharing. The authors explore this question by mapping geocoded home and work locations of respondents within Washington DC and Minneapolis. Respondents were mapped by their modal shift toward or away from bus and rail transit. The results show that in Washington DC, those shifting toward bus and rail transit live on the urban periphery, whereas those living in the urban core tend to use public transit less. In Minneapolis, the shift toward rail extends to the urban core, while the modal shift for bus transit is more dispersed. The authors analyze socio-demographics associated with modal shift through cross-tabulations and four ordinal regression models. Common attributes associated with shifting toward public transit include increased age, being male, living in lower density areas, and longer commute distances. The authors conclude with a discussion of the final results in the context of bikesharing’s impacts on other cities throughout North America.
Dynamic Analysis of Long-Travel, High-Efficiency Shock Absorbers in Freight Cars

A dynamic analysis is presented relating the principal design parameters of a constant force type, dissipative shock absorber to the forces experienced by a resilient lading. The analysis, which correlates the effects of coupler force, lading force, cushion travel, closure time, impact speed, and friction, represents an application of classical mechanics to a dynamical system with sliding friction (Coulomb damping). Although a lumped-parameter analysis forms the basis of the derivation, a procedure is described which takes into account the mass- and compliance distribution within the lading.
Heavy fermion stabilization of solitons in /1+1 dimensions

Abstract We find static solitons stabilized by quantum corrections in a (1+1) -dimensional model with a scalar field chirally coupled to fermions. This model does not support classical solitons. We compute the renormalized energy functional including one-loop quantum corrections. We carry out a variational search for a configuration that minimizes the energy functional. We find a nontrivial configuration with fermion number whose energy is lower than the same number of free fermions quantized about the translationally invariant vacuum. In order to compute the quantum corrections for a given background field we use a phase-shift parameterization of the Casimir energy. We identify orders of the Born series for the phase shift with perturbative Feynman diagrams in order to renormalize the Casimir energy using perturbatively determined counterterms. Generalizing dimensional regularization, we demonstrate that this procedure yields a finite and unambiguous energy functional
On the inertia set of a signed graph with loops

Abstract A signed graph is a pair ( G , Σ ) , where G = ( V , E ) is a graph (in which parallel edges and loops are permitted) with V = { 1 , … , n } and Σ ⊆ E . The edges in Σ are called odd edges and the other edges of E even. By S ( G , Σ ) we denote the set of all n × n real symmetric matrices A = [ a i , j ] such that if a i , j 0 , then among the edges connecting i and j, there must be at least one even edge; if a i , j > 0 , then among the edges connecting i and j, there must be at least one odd edge; and if a i , j = 0 , then either there must be at least one odd edge and at least one even edge connecting i and j, or there are no edges connecting i and j. (Here we allow i = j .) For a real symmetric matrix A, the partial inertia of A is the pair ( p , q ) , where p and q are the number of positive and negative eigenvalues of A, respectively. If ( G , Σ ) is a signed graph, we define the inertia set of ( G , Σ ) as the set of the partial inertias of all matrices A ∈ S ( G , Σ ) . By MR ( G , Σ ) we denote max ⁡ { rank ( A ) | A ∈ S ( G , Σ ) } . We say that a signed graph ( G , Σ ) satisfies the Northeast Property if for each ( p , q ) with p + q MR ( G , Σ ) in the inertia set of ( G , Σ ) , also ( p + 1 , q ) , ( p , q + 1 ) belong to the inertia set of ( G , Σ ) . In this paper, we show that if ( G , Σ ) is a signed graph, where G is a tree with possibly loops attached at some of the vertices, then ( G , Σ ) satisfies the Northeast Property. Furthermore, we present a formula for calculating the inertia set of a signed graph ( G , Σ ) , where G is a tree with possibly loops attached at some of the vertices.
Radiation pions in two-nucleon effective field theory

Abstract For interactions involving two or more nucleons it is useful to divide pions into three classes: potential, radiation, and soft. The momentum threshold for the production of radiation pions is Q r = M N m π . We show that radiation pions can be included systematically with a power counting in Qr. The leading order radiation pion graphs which contribute to NN scattering are evaluated in the PDS and OS renormalization schemes and are found to give a small contribution. The power counting for soft pion contributions is also discussed.
Design, Fabrication, and Performance of Foil Gas Thrust Bearings for Microturbomachinery Applications

ABSTRACT Amethodologyforthedesignandconstructionofsimplefoilthrust bearingsintendedfor parametricperformancetestingandlow marginal costs is presented. Features drawn from a reviewof the openliterature are discussed as they relate to bearingper-formance. The design of ﬁxtures and tooling required to fab-ricate foil thrust bearings is presented, using conventional ma-chining processes where possible. A prototype bearing with di-mensionsdrawnfrom theliteratureis constructed,with allfabri-cationsteps described. Aload-deﬂectioncurvefor thebearingispresented to illustrate structural stiffness characteristics. Start-stop cycles are performed on the bearing at a temperature of425 ◦ C to demonstrate early-life wear patterns. A test of bearingload capacity demonstrates useful performance when comparedwith data obtained from the open literature. Introduction Foil gas bearings represent an enabling technology foradvanced oil-free turbomachinery systems. Operating athigh speeds and temperatures, these next-generation turboma-chines will present tribological challenges that conventional oil-lubricated rolling element bearings may be unable to meet, in-cluding shaft speeds well above three million DN and bearingtemperatures in excess of 400
New Brown Dwarf Disks in the TW Hydrae Association

In our analysis of Spitzer IRS archival data on the stellar and substellar members of the TW Hydrae association (TWA), we have discovered two new brown dwarf disks: a flat, optically thick disk around SSSPM J1102–3431 (SSSPM 1102) and a transition disk around 2MASS J1139511–315921 (2M1139). The disk structure for SSSPM 1102 is found to be very similar to the known brown dwarf disk 2MASSW J1207334–393254 (2M1207), with excess emission observed at wavelengths as short as 5 μm. No excess emission shortward of ~20 μm is seen from 2M1139, but it flares up at longer wavelengths and is the first transition disk detected among the substellar members of the TWA. We also report on Spitzer 70 μm observations and the presence of a 10 μm silicate absorption feature for 2M1207. The absorption can be attributed to a nearly edge-on disk, at 75° inclination. The 10 μm spectrum for 2M1207 shows crystalline forsterite features, with a peak in absorption near 11.3 μm. No silicate absorption or emission is observed toward SSSPM 1102. While only six of 25 stellar members show excess emission at these mid-infrared wavelengths, all of the TWA brown dwarfs that have been observed so far with Spitzer show signs of disks around them, resulting in a disk fraction of at least 60%. This is a considerable fraction at the relatively old age of ~10 Myr. A comparison with younger clusters indicates that by the age of the TWA (~10 Myr), the disk fraction for brown dwarfs has not decreased, whereas it drops by a factor of ~2 for the higher mass stars. This suggests longer disk decay timescales for brown dwarfs as compared with higher mass stars.
Logit Model to Predict Outcomes of Litigated Employee Obesity Cases

Given that there are no specific legal protections for obese employees, the purpose of this study was to investigate the relationship between the litigated case characteristics and case outcomes when an employee is subjected to negative consequences in the workplace and subsequently sues the employer. The study is an analysis of a random sample of 276 litigated cases based on adverse employment decisions of individuals who were obese. These cases were retrieved using Lexis/Nexis over the past 10 years. Eighty cases were included in the empirical analysis. This analysis considered demographic characteristics, organizational and cases characteristics, legal bases, and confounding physical factors. Multivariate logistic regression was performed in order to investigate the effect of the independent variables. The employee prevailed in almost 40% of the cases. The case characteristics associated with the employer prevailing included the employee being a professional, being in the public sector and filing lawsuits under discrimination, health and disability laws. Some of the findings are contrary to popular perception. Obese employees have legal protections under various discrimination laws, even though there does not seem to be explicit protections under the law. Thus, organizations must be more vigilant in sanctioning obesity. However, this sanctioning is neither a disability nor a gender issue. This is the first study using qualitative content analysis of litigated cases and logistic regression to analyze litigated cases in which obese employees were disciplined.
Models of quasi-periodic variability in neutron stars and black holes

Abstract Black holes and weakly-magnetic accreting neutron stars show strong quasi-periodic variability over timescales that span a very wide range. This property offer us a unique opportunity to improve our understanding of basic physical processes in strong gravitational fields as it reveals, for the first time, phenomena that occur on the most fundamental timescales near accreting compact objects. In this article, I review our current understanding of the variability properties of accretion flows onto neutron stars and black holes. I discuss a number of challenges faced by theoretical models, in order to identify open questions in accretion physics that need to be addressed. Finally, I discuss the relation to and implications for variability models of the detection of nearly coherent oscillations during type I X-ray bursts in several neutron-star sources.
Flow properties of DDGS with varying soluble and moisture contents using jenike shear testing

Distillers dried grains with solubles (DDGS) are an excellent source of energy, minerals, and bypass protein for ruminants and are used in monogastric rations as well. With the remarkable growth of the US fuel ethanol industry in the past decade, large quantities of distillers grains are now being produced. Flow of DDGS is often restricted by caking and bridging during its storage and transportation. In our previous works, the Carr powder tester was used to measure various flow properties of DDGS. The objective of this study was to measure the flow properties (cohesion, effective angle of friction, internal angle of friction, yield locus, flow function, major consolidating stress, and unconfined yield strength) of DDGS using the Jenike shear tester. This work investigated the influence of four levels of solubles (10, 15, 20, and 25% db) and five levels of moisture content (10, 15, 20, 25, and 30% db) on the resulting flow properties of DDGS. With an increase in soluble levels, the flow function curves of DDGS shift in an anticlockwise direction towards the shear stress (σc) axis. Depending on the soluble level, above certain moisture contents, the moisture actually began acting as a lubricant, easing the flow of the DDGS. Also, with higher solubles and moisture levels, the compressibility of DDGS was found to increase. Overall, the DDGS was classified as a cohesive material, and it is likely to produce cohesive arching problems.
A finite-state, finite-memory minimum principle

A class of finite-state, finite-memory stochastic control problems is considered. A minimum principle is derived. Signaling strategies are defined and related to the necessary conditions of the minimum principle. Min-H algorithms for the problem are described.
On an algebraic approach to higher-dimensional statistical mechanics

We study representations of Temperley-Lieb algebras associated with the transfer matrix formulation of statistical mechanics on arbitrary lattices. We first discuss a new hyperfinite algebra, the Diagram algebra $$D_{\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle-}$}}{n} } (Q)$$ , which is a quotient of the Temperley-Lieb algebra appropriate for Potts models in the mean field case, and in which the algebras appropriate for all transverse lattice shapesG appear as subalgebras. We give the complete structure of this subalgebra in the case $$\hat A_n$$ (Potts model on a cylinder). The study of the Full Temperley Lieb algebra of graphG reveals a vast number of infinite sets of inequivalent irreducible representations characterized by one or more (complex) parameters associated to topological effects such as links. We give a complete classification in the $$\hat A_n$$ case where the only such effects are loops and twists.
Beyond worst-case analysis for joins with minesweeper

We describe a new algorithm, Minesweeper, that is able to satisfy stronger runtime guarantees than previous join algorithms (colloquially ``beyond worst-case'' guarantees) for data in indexed search trees. Our first contribution is developing a framework to measure this stronger notion of complexity, which we call "certificate complexity," that extends notions of Barbay et al. and Demaine et al.; a certificate is a set of propositional formulae that certifies that the output is correct. This notion captures a natural class of join algorithms. In addition, the certificate allows us to define a strictly stronger notion of runtime complexity than traditional worst-case guarantees. Our second contribution is to develop a dichotomy theorem for the certificate-based notion of complexity. Roughly, we show that Minesweeper evaluates $\beta$-acyclic queries in time linear in the certificate plus the output size, while for any $\beta$-cyclic query, there is some instance that takes superlinear time in the certificate (and for which the output is no larger than the certificate size). We also extend our certificate-complexity analysis to queries with bounded treewidth and the triangle query. We present empirical results that certificates can be much smaller than the input size, which suggests that ideas in minesweeper might lead to faster algorithms in practice.
Perfect Pairs of Ideals and Duals in Numerical Semigroups

This article considers numerical semigroups S that have a nonprincipal relative ideal I such that μ S (I)μ S (S − I) = μ S (I + (S − I)). We show the existence of an infinite family of such pairs (S, I) in which I + (S − I) = S\{0}. We also show examples of such pairs that are not members of this family. We discuss the computational process used to find these examples and present some open questions pertaining to them.
Applications and mechanisms of charge-remote fragmentation

Studies on the applications, energetics, and mechanisms of charge-remote fragmentations are reviewed, with emphasis given to those articles published after 1992. Independent of the charge status, charge-remote fragmentations are analogous to gas-phase thermolysis. Under collisional activation and with a fixed charge, ions containing long-chain or poly-ring structures undergo charge-remote fragmentations, generating productions that are structurally informative. Interpretation of the production spectra enables one to elucidate molecular structures. Although charge-remote fragmentations have been successfully used in the structural determination of fatty acids, phospholipids, glycolipids, triacylglycerols, steroids, peptides, ceramides, and other systems, the energetics and mechanisms of these reactions are still debated because none of the existing mechanisms can explain all the experimental data.
Inverse Design of Coolant Flow Passage Shapes With Partially Fixed Internal Geometries

A method is described for the inverse design of complex coolant flow passage shapes in internally cooled turbine blades. This method is a refinement and extension of a method developed by the authors for designing a single coolant hole in turbine blades. The new method allows the turbine designer to specify the number of holes the turbine blade is to have. In addition, the turbine designer may specify that certain portions of the interior coolant flow passage geometry are to remain fixed (eg. struts, surface coolant ejection channels, etc.). Like the original design method, the designer must specify the outer blade surface temperature and heat flux distribution and the desired interior coolant flow passage surface temperature distributions. This solution procedure involves satisfying the dual Dirichlet and Neumann specified boundary conditions of temperature and heat flux on the outer boundary of the airfoil while iteratively modifying the shapes of the coolant flow passages using a least squares optimization procedure that minimizes the error in satisfying the specified Dirichlet temperature boundary condition on the surface of each of the evolving interior holes. Portions of the inner geometry that are specified to be fixed are not modified. A first order panel method is used to solve Laplace’s equation for the steady heat conduction within the solid portions of the hollow blade, making the inverse design procedure very efficient and applicable to realistic geometries. Results are presented for a realistic turbine blade design problem.Copyright © 1985 by ASME
Disagreement and epistemic arguments for democracy

Recent accounts of epistemic democracy aim to show that in some qualified sense, democratic institutions have a tendency to produce reasonable outcomes. Epistemic democrats aim to offer such accoun...
Photochemistry of 4‐phenyl‐1,3‐dioxolan‐2‐one

The photolysis of the mono substituted cyclic carbonate ester 4-phenyl-1,3-dioxolan-2-one has been studied. The direct irradiation results in loss of carbon dioxide with the formation of the corresponding ox-irane, styrene oxide as well as phenylacetaldehyde and bibenzyl. Photolysis in methanol produces the same compounds in addition to phenethyl alcohol and 2-methoxy-2-phenylethanol. Triplet sensitized photolyses resulted in the products derived entirely from benzyl radicals with none of the oxirane being detected.
Diverse polyanions based on MnBi4 and MnSb4 tetrahedra: polymorphism, structure, and bonding in Ca21Mn4Bi18 and Ca21Mn4Sb18.

New transition-metal-containing Zintl phases, Ca21Mn4Bi18 and Ca21Mn4Sb18, have been synthesized by high-temperature reactions, and their structures have been determined by single-crystal X-ray diffraction. Ca21Mn4Bi18 crystallizes in the monoclinic space group C2/c (No. 15, Z = 4) with a = 17.470(2) A, b = 17.392(2) A, c = 17.208(2) A, β = 93.253(2)° (R1 = 0.0405, wR2 = 0.0840) and is isostructural with the recently reported Ca21Mn4Sb18. The compound with the same formula, which is also reported herein, is in turn a new polymorph of Ca21Mn4Sb18 and crystallizes in the monoclinic space group C2/m (No. 12, Z = 4) with a = 17.415(6) A, b = 16.567(6) A, c = 17.047(6) A, β = 92.068(4)° (R1 = 0.0432, wR2 = 0.0788). This new polymorph of Ca21Mn4Sb18 is isostructural with another related compound, Sr21Mn4Sb18. Despite the similarity in their chemical formulas, the structures of Ca21Mn4Bi18 and Ca21Mn4Sb18 are very different: Ca21Mn4Bi18 contains unique [Mn4Bi10] cluster anions made up of four MnBi4 tetrahedra c...
Alternative methods of calculating optimal timber rotations: a critique of the Stokey/Lucas/Prescott tree-cutting problem.

The traditional question of optimally deciding when to cut down a tree is among the most commonly posed questions asked of students learning the technique of dynamic programming. This paper shows that the traditional tree-cutting example is improperly formulated when the question of replanting is addressed, derives the proper method of finding optimal harvest length, and applies this method to an empirical forest growth function.
Rare kaon decays

The phenomenology of rare kaon decays is reviewed, with emphasis on tests of standard model flavordynamics.
Chemical Consequences of the C/O Ratio on Hot Jupiters: Examples from WASP-12b, CoRoT-2b, XO-1b, and HD 189733b

Motivated by recent spectroscopic evidence for carbon-rich atmospheres on some transiting exoplanets, we investigate the influence of the C/O ratio on the chemistry, composition, and spectra of extrasolar giant planets both from a thermochemical equilibrium perspective and from consideration of disequilibrium processes like photochemistry and transport-induced quenching. We find that although CO is predicted to be a major atmospheric constituent on hot Jupiters for all C/O ratios, other oxygen-bearing molecules like H2O and CO2 are much more abundant when C/O 1. Other notable species like N2 and NH3 that do not contain carbon or oxygen are relatively unaffected by the C/O ratio. Disequilibrium processes tend to enhance the abundance of CH4, NH3, HCN, and C2H2 over a wide range of C/O ratios. We compare the results of our models with secondary-eclipse photometric data from the Spitzer Space Telescope and conclude that (1) disequilibrium models with C/O ~ 1 are consistent with spectra of WASP-12b, XO-1b, and CoRoT-2b, confirming the possible carbon-rich nature of these planets; (2) spectra from HD 189733b are consistent with C/O 1, but as the assumed metallicity is increased above solar, the required C/O ratio must increase toward 1 to prevent too much H2O absorption; (3) species like HCN can have a significant influence on spectral behavior in the 3.6 and 8.0 μm Spitzer channels, potentially providing even more opacity than CH4 when C/O > 1; and (4) the very high CO2 abundance inferred for HD 189733b from near-infrared observations cannot be explained through equilibrium or disequilibrium chemistry in a hydrogen-dominated atmosphere. We discuss possible formation mechanisms for carbon-rich hot Jupiters, including scenarios in which the accretion of CO-rich, H2O-poor gas dominates the atmospheric envelope, and scenarios in which the planets accrete carbon-rich solids while migrating through disk regions inward of the snow line. The C/O ratio and bulk atmospheric metallicity provide important clues regarding the formation and evolution of the giant planets.
Abundance Patterns in the Draco, Sextans, and Ursa Minor Dwarf Spheroidal Galaxies

The Keck I telescope and the High Resolution Echelle Spectrometer (HIRES) have been used to obtain spectra for red giant stars belonging to the Draco, Sextans, and Ursa Minor dwarf spheroidal (dSph) galaxies. An analysis of these spectra is presented, along with abundance ratios for more than 20 elements. The resulting database of element abundances for 17 dSph stars is the most extensive yet assembled for stars in such environments. Our principal findings are summarized as follows. (1) There is unambiguous evidence for a large internal dispersion in metallicity in all three galaxies: our program stars span a range of ?[Fe/H] = 1.53, 1.40, and 0.73 dex in Draco, Sextans, and Ursa Minor, respectively. (2) The abundance patterns among the dSph stars are remarkably uniform, suggesting that three galaxies have similar nucleosynthetic histories and, presumably, similar initial mass functions. (3) A comparison of the measured element abundance ratios for our sample of dSph stars with published values for Galactic halo and disk field stars suggests that the dSph galaxies have 0.02 [?/Fe] 0.13 dex, whereas the halo field star sample has [?/Fe] ~ 0.28 dex over the same range in metallicity. (4) The most metal-rich dSph stars in our sample have [Y/Fe] abundances that are significantly lower than those measured for halo field stars of similar metallicity, while the measured [Ba/Eu] ratios for the dSph stars suggest that the early chemical evolution of these galaxies was dominated by the r-process. Taken together, these results suggest that the Galactic halo is unlikely to have assembled, in its entirety, through the disruption of dwarf galaxies similar to the low-luminosity, LV = 3 ? 105LV,?, dSph galaxies studied here. We also note that the measured [Zn/Fe] abundance ratios for the dSph stars are lower than those of damped Ly? systems having low levels of dust depletion by roughly an order of magnitude. The first high-resolution abundance analysis for the distant Galactic globular cluster NGC 2419 is also presented. From a HIRES spectrum of a single red giant, we find a metallicity of [Fe/H] = -2.32 ? 0.11 dex. This is slightly lower than, but still consistent with, published estimates based on low-resolution spectroscopy. With the possible exception of a slight enhancement in the abundances of some heavy elements such as Ce, Nd, Y, and Ba, the observed abundance pattern closely resembles those exhibited by red giants in M92: a nearby, well-studied globular cluster of nearly identical metallicity.
A proline-catalyzed asymmetric Robinson annulation reaction

Abstract A single-step enantioselective synthesis of the Wieland–Miescher ketone ( 5 ) is presented. We show that l -proline as well as a number of other chiral amines can act as catalysts of both steps of the Robinson annulation reaction. Other chiral amines are identified as catalysts of Michael and aldol addition reactions.
Targeted removal of bioavailable metal as a detoxification strategy for carbon nanotubes

There is substantial evidence for toxicity and/or carcinogenicity upon inhalation of pure transition metals in fine particulate form. Carbon nanotube catalyst residues may trigger similar metal-mediated toxicity, but only if the metal is bioavailable and not fully encapsulated within fluid-protective carbon shells. Recent studies have documented the presence of bioavailable iron and nickel in a variety of commercial as-produced and vendor "purified" nanotubes, and the present article examines techniques to avoid or remove this bioavailable metal. First, data are presented on the mechanisms potentially responsible for free metal in "purified" samples, including kinetic limitations during metal dissolution, the re-deposition or adsorption of metal on nanotube outer surfaces, and carbon shell damage during last-step oxidation or one-pot purification. Optimized acid treatment protocols are presented for targeting the free metal, considering the effects of acid strength, composition, time, and conditions for post-treatment water washing. Finally, after optimized acid treatment, it is shown that the remaining, non-bioavailable (encapsulated) metal persists in a stable and biologically unavailable form up to two months in an in vitro biopersistence assay, suggesting that simple removal of bioavailable (free) metal is a promising strategy for reducing nanotube health risks.
Polynomial maps over finite fields and residual finiteness of mapping tori of group endomorphisms

We prove that every mapping torus of any free group endomorphism is residually finite. We show how to use a not yet published result of E. Hrushovski to extend our result to arbitrary linear groups. The proof uses algebraic self-maps of affine spaces over finite fields. In particular, we prove that when such a map is dominant, the set of its fixed closed scheme points is Zariski dense in the affine space.
Sufficient conditions for double or unique solution of motion and structure

Abstract This paper presents several sufficient conditions for a double or unique solution of the problem of motion and structure estimation of a rigid surface from pairs of monocular images. These conditions further the understanding of the uniqueness problem of rigid motion solution. We will show that five correspondences of noncolinear points that do not lie on a special type of quadratic curve, called a Maybank curve, in the image plane suffice to determine a pure rotation uniquely, and six correspondences of points that do not correspond to space points lying on a Maybank quadric suffice to determine a motion with nonzero translation uniquely. We will show that each Maybank quadric can sustain at most two physically acceptable motion solutions and surface interpretations, provided that a sufficient number of correspondences are present. In particular, we will show that in the plane motion case, six correspondences of points that do not lie on a quadratic curve in the image plane will admit only the true motion and structure and their duals as solutions. We will discuss how noise affects the uniqueness of solution and present a nonlinear algorithm for estimation of motion parameters. We will list several properties of the essential matrix T × R and the plane motion matrix R + TN τ , both of which are frequently used in the motion and structure estimation problem. Simulation results are provided for verifying the theorems in this paper.
Two stage phase transition in two Higgs models

Abstract We present a mechanism in which models with two Higgs fields can undergo a two stage phase transition as the temperature falls. The first stage is a conventional second order (or weakly first order) transition in which the symmetry is broken. Shortly thereafter follows a first order transition with barrier penetration, bubble production and loss of thermal equilibrium. For Higgs potentials with CP violation, we show that the second stage of the transition has all the features required for weak scale baryogenesis.
Optical Properties of Anatase, Rutile and Amorphous Phases of TiO 2 Thin Films Grown at Room Temperature by RF Magnetron Sputtering

Anatase (A), rutile (R) and amorphous phase TiO2 thin films have been prepared by RF magnetron sputtering on unheated glass substrates by controlling the total pressure of sputtering gases (Ar + O2) and the substrate bias. The crystal structures of the films were confirmed by x-ray diffraction and Raman scattering. The analysis of optical absorption data for A- TiO2 film shows an energy bandgap (Eg) of 3.2 eV (indirect extrapolation) and ∼ 3.5 eV (direct extrapolation). On the other hand, R-TiO2 film shows Eg ∼ 2.9 eV (indirect) and 3.2 eV (direct). The latter film also shows the presence of amorphous regions with Eg ∼ 3.0 eV (indirect) and 3.8 eV (direct). The bandgap of both the films, obtained using indirect extrapolation, has a value range consistent with the previous measurements.
Probabilities and beliefs

Choice-theoretic definitions of subjective probabilities originated with the work of Ramsey and de Finetti and attained their definitive form in the work of Savage. These probabilities are intended to provide a numerical representation of a decision maker's beliefs regarding the likely realization of alternative events. In this article, I argue that the choice-theoretic definitions of subjective probabilities involve a tacit convention—namely, state-independent utility functions—that is not implied by the axioms, and, as a consequence, choice-theoretic subjective probabilities, even when they exist, do not necessarily represent the decision makers' beliefs.