cssi/SciSciGPT-SciSciNet huggingface dataset:
Effect of surface pretreatment on the galvanostatic oxidation of nickel

Abstract The open-circuit, cathodic reduction and anodic charging characteristics of oxide films on both electropolished and electropolished + HNO 3 etched nickel electrodes have been studied in aqueous Na 2 SO 4 solutions. While the oxide film thicknesses are approximately the same, the film on etched nickel dissolves much more rapidly than that on electropolished nickel. To galvanostatically passivate etched nickel at charging rates in the range 20–200 μA cm −2 in pH 2.8 Na 2 SO 4 , the rate of oxide chemical dissolution has to be substantially decreased and this is achieved by lowering the electrolyte temperature from 25°C to 5°C. The transient anodic passivation charge thus observed for etched nickel is ∼ 2 x larger than that for electropolished nickel. With either pretreatment, the current efficiency for oxide formation is low (∼ 20%), the majority of the transient charge (∼ 80%) accounted for by Ni 2+ in solution. Chemical dissolution of the oxide alone cannot explain the observed charging differences between etched and electropolished nickel since the individual charges and oxide formation current efficiencies are not influenced by anodic charging rate or solution aggressiveness. The results are best explained in terms of a continual breakdown and repair of the oxide film at defect areas during anodic charging, with most of the charge consumed by inefficient film repair. The influence of the oxide defects and the reason for the differences in behaviour between electropolished and etched nickel are discussed.
Improving foldamer synthesis through protecting group induced unfolding of aromatic oligoamides.

The hydrogen bond rigidified backbones of aromatic oligoamides are temporarily interrupted by replacing the amide hydrogens with the acid-labile 2,4-dimethoxybenzyl (DMB) group, which allows the efficient preparation of long folding oligomers that, upon removal of the DMB groups, fold into multiturn helices.
Nanostructured Titania: the current and future promise of Titania nanotubes

Titania nanotubes (TiNT) combine unique nanotubular morphology with the desirable electronic, optical, and chemical properties of nanostructured titania. This perspective provides an overview of the three major synthesis methods for TiNT and the corresponding physical and chemical characteristics of the material. Promising applications in photocatalysis are explored with special emphasis on recent insights in the photooxidative and photoreductive activity of TiNT materials. The major challenge for future work is to connect observed improvements in catalytic activity with an understanding of the fundamental processes in photocatalysis in order to tailor the structure of TiNT composites to targeted functions.
Active Stabilization of Rotating Stall in a Three-Stage Axial Compressor

A three-stage, low-speed axial research compressor has been actively stabilized by damping low-amplitude circumferentially traveling waves, which can grow into rotating stall. Using a circumferential array of hot-wire sensors, and an array of high-speed individually positioned control vanes as the actuator, the first and second spatial harmonics of the compressor were stabilized down to a characteristic slope of 0.9, yielding an 8 percent increase in operating flow range. Stabilization of the third spatial harmonic did not alter the stalling flow coefficient. The actuators were also used open loop to determine the forced response behavior of the compressor
Automata generating free products of groups of order 2

Abstract We construct a family of automata with n states, n ⩾ 4 , acting on a rooted binary tree that generate the free products of cyclic groups of order 2.
Oligo-Parametric Hierarchical Structure of Complex Systems

We investigate the possible origin of hierarchical structures in complex systems describable in terms of a finite and small number of parameters which control the behavioral pattern at each level of organization. We argue that the limitation on the number of important parameters at each stage is a reflection of the fact that Thom’s classifications of catastrophes, i.e., qualitative changes, involve only a few parameters. In addition, we also point out that even in systems with a large number of components, only a few may be of statistically great significance, just as in Zipf’s law the quantitative measure of the important collections is inversely proportional to the rank. We then consider the concept of relative degeneracies coming from change of resolving power, at various scales, which too would vindicate the procedure of coarse-graining in building up hierarchical organizations. We suggest that, similar to the group-theoretical annihilation of dangling tensor indices due to symmetry to minimize energy, even in more inexact contexts such as in biology and the social sciences, similar attempts by the system to reduce frustration may lead to cluster formation, which are semi-closed, and let leakage interactions come into play at larger scales.
Polygyny, Fertility, and Savings

Sub‐Saharan Africa has a high incidence of polygyny. It is also the poorest region of the world. In this paper I ask whether banning polygyny could play any role for development. Using a quantitative model of polygyny, I find that enforcing monogamy lowers fertility, shrinks the spousal age gap, and reverses the direction of marriage payments. Polygyny leads to high bride‐prices to “ration” women, which makes buying wives and selling daughters a good investment, thus crowding out investment in physical assets. For reasonable parameter values, I find that banning polygyny decreases fertility by 40 percent, increases savings by 70 percent, and increases output per capita by 170 percent.
Finite size percolation in regular trees

Abstract In the context of percolation in a regular tree, we study the size of the largest cluster and the length of the longest run starting within the first d generations. As d tends to infinity, we prove almost sure and weak convergence results.
Hysteresis and noise in stripe- and clump-forming systems

We use simulations to examine hysteresis and noise in a model system that produces heterogeneous orderings including stripe and clump phases. In the presence of a disordered substrate, these heterogeneous phases exhibit 1/fα noise and hysteresis in transport. The noise fluctuations are maximal in the heterogeneous phases, while in the uniform phases the hysteresis vanishes and both α and the noise power decrease. We compare our results to recent experiments exhibiting noise and hysteresis in high-temperature superconductors where charge heterogeneities may occur.
High-Resolution LDA Measurements of Reynolds Stress in Boundary Layers and Wakes

The turbulent character of the boundary layer and wake associated with an airfoil has been studied at a Reynolds number of 10(exp 6) and a Mach number of 0.1. To accomplish these measurements, a unique laser Doppler anemometer (LDA) has been developed that is capable of sensing two velocity components from a remote distance of 2.13 m. Using special simultaneity logic and counter-type signal processors, the geometrical features of the LDA have been exploited to provide variable spatial resolution as low as 0.2 mm. By combining the LDA with an on-line computerized data acquisition and display system, it has been possible to measure mean velocity and Reynolds stress tensor distribution at several locations along the upper surface of a 0.9 m chord, flapped airfoil installed in the Ames 7- by 10-Foot Wind Tunnel.
Dynamic social grouping based routing in a Mobile Ad-Hoc network

The patterns of movement used by Mobile Ad-Hoc networks are application specific, in the sense that networks use nodes which travel in different paths. When these nodes are used in experiments involving social patterns, such as wildlife tracking, algorithms which detect and use these patterns can be used to improve routing efficiency. The intent of this paper is to introduce a routing algorithm which forms a series of social groups which accurately indicate a node's regular contact patterns while dynamically shifting to represent changes to the social environment. With the social groups formed, a probabilistic routing schema is used to effectively identify which social groups have consistent contact with the base station, and route accordingly. The algorithm can be implemented dynamically, in the sense that the nodes initially have no awareness of their environment, and works to reduce overhead and message traffic while maintaining high delivery ratio.
Pattern formation in the Drosophila embryo.

Three plausible hypotheses about developmental commitments in the Drosophila embryo propose that: (1) a micromosaic of localized determinants in the egg trigger somatic commitments; (2) monotonic anterior-posterior and dorsal-ventral gradients in the egg specify positions by a series of threshold values; (3) sequential subdivision of the early embryo into \`anterior' or \`posterior' \`middle' or \`end', \`dorsal' or \`ventral', \`odd' or \`even' compartmental domains encodes the somatic commitment in each region in a combinatorial epigenetic code. Evidence in favour of such a combinatorial code includes its capacity to account for major features of transdetermination and for many single and coordinated homoeotic transformations. In particular, both these metaplasias often cause transformations between ectodermal tissues such as antenna and genitalia, whose anlagen lie far apart on the blastoderm fate map. This phenomenon is not naturally explained by monotonic gradient models. In contrast, not only transformation between distant regions of the fate map, but also the observed geometries of compartmental boundaries on the wing, and probable ones in the early embryo, are naturally explained by reaction-diffusion models. These systems form a discrete succession of differently shaped monotonic and non-monotonic eigenfunction gradient patterns of the same morphogens, as the tissue containing the chemical system changes in size and shape, or in other parameters. The successive mirror symmetries in non-monotonic gradients predict that distant regions of the embryo make similar developmental commitments, and also predict specific classes of pattern mutants forming mirror symmetric structures along the embryo on a variety of length scales. Finally, reaction diffusion systems spontaneously generate transverse gradients of the underlying chemicals when more than one eigenfunction is amplified at once, and therefore specify two-dimensional positional information within domains. Although it is attractive, no feature of the combinatorial code hypothesis is verified. Current data relating to whether the sequential formation of compartmental boundaries actually reflects the commitment of the two isolated \`polyclones' to alternative fates, whether any genes act continuously to maintain disc commitments, and whether homoeotic mutants actually \`switch' disc determined states, are assessed.
Phonon Transport in Anisotropic Scattering Particulate Media

Equation of phonon radiative transport (EPRT) is rewritten to include anisotropic scattering by a particulate media by including an acoustic phase function and an inscattering term which makes EPRT exactly same as equation of radiative transport (ERT). This formulation of EPRT is culled generalized EPRT (GEPRT). It is shown that GEPRT reduces to EPRT for isotropic scattering and is totally consistent with phonon transport theory, showing that transport cross section is different from the scattering cross section. GEPRT leads to same formulation for transport cross section as given by phonon transport theory. However GEPRT shows that transport cross section formulations as described by phonon transport theory are only valid for acoustically thick medium. Transport cross section is different for the acoustically thin medium leading to the conclusion that mean free path (m.f.p) is size dependant. Finally calculations are performed for two types of scatterers for acoustic waves without mode conversion: (1) acoustically hard Rciyleiglr sphere; and (2) large sphere in the geometrical scattering regime. Results show that the scattering from these particles is highly anisotropic. It is also shown that for geometrical scattering case isotropic scattering leads to the conclusion of total internal reflection at the particle/medium interface.
Membrane dynamics in M(atrix)-theory

Abstract We analyze some of the kinematical and dynamical properties of flat infinite membrane solutions in the conjectured M theory proposed by Banks, Fischler, Shenker and Susskind. In particular, we compute the long range potential between membranes and anti-membranes, and between membranes and gravitons, and compare it with the supergravity results. We also discuss membranes with finite relative longitudinal velocities, providing some evidence for the 11-dimensional Lorentz invariance of the theory.
3D free-form object recognition in range images using local surface patches

This paper introduces an integrated local surface descriptor for surface representation and 3D object recognition. A local surface descriptor is characterized by its centroid, its local surface type and a 2D histogram. The 2D histogram shows the frequency of occurrence of shape index values vs. the angles between the normal of reference feature point and that of its neighbors. Instead of calculating local surface descriptors for all the 3D surface points, they are calculated only for feature points that are in areas with large shape variation. In order to speed up the retrieval of surface descriptors and to deal with a large set of objects, the local surface patches of models are indexed into a hash table. Given a set of test local surface patches, votes are cast for models containing similar surface descriptors. Based on potential corresponding local surface patches candidate models are hypothesized. Verification is performed by running the Iterative Closest Point (ICP) algorithm to align models with the test data for the most likely models occurring in a scene. Experimental results with real range data are presented to demonstrate and compare the effectiveness and efficiency of the proposed approach with the spin image and the spherical spin image representations.
MOS GP computer

When the 2-phase, 20-bit shift registers using P-channel enhancement mode MOS-FET's were first introduced on the market many of us did not have the foggiest idea of what a MOS-FET was. Logical designers were intrigued by the functional complexity which the technology appeared to offer. System designers were pleased with the prospect of lower power and fewer package requirements. Semiconductor manufacturers predicted that MOS would be forgotten sooner than the tunnel diode.
Asset Maturity, Debt Covenants, and Debt Maturity Choice

The existing research on debt-maturity under asymmetric information has focused on the impact of differential information regarding asset quality on the debt maturity decision. This research has generally indicated the optimality of short-term debt financing as a vehicle of mitigating the adverse selection problem. In this paper, I consider the impact of information asymmetry regarding the maturity structure of cash flows on the debt maturity decision. In this context, long-term debt is generally the form of debt financing most effective in alleviating the adverse selection problem. I also show that costs of adverse selection may induce some mismatching of debt maturity and asset maturity in the presence of significant transaction costs.
Mechanical Properties and Failure Analysis of Alumina‐Glass Dental Composites

Strength measurements and fractography were used to investigate the failure of alumina-glass dental composites containing 75 vol% alumina and 25 vol% glass. Alumina compacts were prepared by slip casting and sintering at 1100°C for 2 h. Dense composites were made by infiltrating partially sintered alumina with glass at 1150°C for 8 h. Young's modulus and the hardness of the composites were 270 GPa and 12 GPa, respectively. The mean strength (460 MPa) and fracture toughness (4.0 MPa·m1/2) of the composites were insensitive to the glass thermal expansion coefficient (αglass= 5.9 × 10−6 to 7.8 × 10−6°C−1). Typical flaws were pores and cracklike voids formed by poor particle packing and differential sintering near agglomerates of alumina in the composite. Crack deflection and crack bridging were observed in indentation cracks. Fracture toughness was single-valued because the alumina particle size was small (∼3 μm). Alumina-glass composites are promising new ceramics for dental crown and bridge applications, because their strength and fracture toughness are ∼2 times greater than those of current dental ceramics.
A concise synthesis of optically active 2-bromotryptophan amino acids present in konbamide and jaspamide via a regiospecific bromination procedure

Abstract A highly stereoselective synthesis of optically active 2-bromo-5-hydroxy-tryptophan 1a and important derivatives 1b and 1c as well as their 2-bromotryptophan analogs was achieved in three steps from 2-bromo-3-bromomethylindoles 3a and 3b , respectively.
Nucleophilic addition to olefins. Kinetics and mechanism

Addition d'eau, de l'ion hydroxyde, d'amines, d'ions thiolates, de CN − , N 3 − , F − , RO − , et de carbanions. Scission et aminolyse de la liaison c=c
Alkoxide Clusters of Molybdenum and Tungsten as Templates for Organometallic Chemistry: Comparison with Carbonyl Clusters of the Later Transition Elements

Alkoxide and carbonyl ligands complement each other because they both behave as “π buffers” to transition metals. Alkoxides, which are π donors, stabilize early transition metals in high oxidation states by donating electrons into vacant dπ orbitals, whereas carbonyls, which are π acceptors, stabilize later transition elements in their lower oxidation states by accepting electrons from filled dπ orbitals. Both ligands readily form bridges that span MM bonds. In solution fluxional processes that involve bridge–terminal ligand exchange are common to both alkoxide and carbonyl ligands. The fragments [W(OR)3], [CpW(CO)2], [Co(CO)3], and CH are related by the isolobal analogy. Thus the compounds [(RO)3W W(OR)3], [Cp(CO)2WW(CO)2Cp], hypothetical [(CO)3CoCo(CO)3], and HCCH are isolobal. Alkoxide and carbonyl cluster compounds often exhibit striking similarities with respect to substrate binding—e.g., [W3(μ3-CR)(OR′)9] versus [Co3(μ3-CR)(CO)9] and [W4(C)(NMe)(OiPr)12] versus [Fe4(C)(CO)13]—but differ with respect to MM bonding. The carbonyl clusters use eg-type orbitals for MM bonding whereas the alkoxide clusters employ t2g-type orbitals. Another point of difference involves electronic saturation. In general, each metal atom in a metal carbonyl cluster has an 18-electron count; thus, activation of the cluster often requires thermal or photochemical CO expulsion or MM bond homolysis. Alkoxide clusters, on the other hand, behave as electronically unsaturated species because the π electrons are ligand-centered and the LUMO metal-centered. Also, access to the metal centers may be sterically controlled in metal alkoxide clusters by choice of alkoxide groups whereas ancillary ligands such as tertiary phosphanes or cyclopentadienes must be introduced if steric factors are to be modified in carbonyl clusters. A comparison of the reactivity of alkynes and ethylene with dinuclear alkoxide and carbonyl compounds is presented. For the carbonyl compounds CO ligand loss is a prerequisite for substrate uptake and subsequent activation. For [M2(OR)6] compounds (M = Mo and W) the nature of substrate uptake and activation is dependent upon the choice of M and R, leading to a more diverse chemistry.
α-Selective Ni-Catalyzed Hydroalumination of Aryl- and Alkyl-Substituted Terminal Alkynes: Practical Syntheses of Internal Vinyl Aluminums, Halides, or Boronates

A method for Ni-catalyzed hydroalumination of terminal alkynes, leading to the formation of alpha-vinylaluminum isomers efficiently (>98% conv in 2-12 h) and with high selectivity (95% to >98% alpha), is described. Catalytic alpha-selective hydroalumination reactions proceed in the presence of a reagent (diisobutylaluminum hydride; dibal-H) and 3.0 mol % metal complex (Ni(dppp)Cl(2)) that are commercially available and inexpensive. Under the same conditions, but with Ni(PPh(3))(2)Cl(2), hydroalumination becomes highly beta-selective, and, unlike uncatalyzed transformations with dibal-H, generates little or no alkynylaluminum byproducts. All hydrometalation reactions are reliable, operationally simple, and practical and afford an assortment of vinylaluminums that are otherwise not easily accessible. The derived alpha-vinyl halides and boronates can be synthesized through direct treatment with the appropriate electrophiles [e.g., Br(2) and methoxy(pinacolato)boron, respectively]. Ni-catalyzed hydroaluminations can be performed with as little as 0.1 mol % catalyst and on gram scale with equally high efficiency and selectivity.
Default Risk Cannot Explain the Muni Puzzle: Evidence from Municipal Bonds that are Secured by U.S. Treasury Obligations

Fama (1977) and Miller (1977) predict that one minus the corporate tax rate will equate after-tax yields from comparable taxable and tax-exempt bonds. Empirical evidence shows that long-term tax-exempt yields are higher than theory predicts. Two popular explanations for this empirical puzzle are that, relative to taxable bonds, municipal bonds bear more default risk and include costly call options. I study U.S. government secured municipal bond yields which are effectively default-free and nonmalleable. These municipal yields display the same tendency to be too high. I conclude that differential default risk and call options do not explain the municipal bond puzzle. Article published by Oxford University Press on behalf of the Society for Financial Studies in its journal, The Review of Financial Studies.
Ultrawrap: SPARQL execution on relational data

The Semantic Web's promise of web-wide data integration requires the inclusion of legacy relational databases, i.e. the execution of SPARQL queries on RDF representation of the legacy relational data. We explore a hypothesis: existing commercial relational databases already subsume the algorithms and optimizations needed to support effective SPARQL execution on existing relationally stored data. The experiment is embodied in a system, Ultrawrap, that encodes a logical representation of the database as an RDF graph using SQL views and a simple syntactic translation of SPARQL queries to SQL queries on those views. Thus, in the course of executing a SPARQL query, the SQL optimizer uses the SQL views that represent a mapping of relational data to RDF, and optimizes its execution. In contrast, related research is predicated on incorporating optimizing transforms as part of the SPARQL to SQL translation, and/or executing some of the queries outside the underlying SQL environment. Ultrawrap is evaluated using two existing benchmark suites that derive their RDF data from relational data through a Relational Database to RDF (RDB2RDF) Direct Mapping and repeated for each of the three major relational database management systems. Empirical analysis reveals two existing relational query optimizations that, if applied to the SQL produced from a simple syntactic translations of SPARQL queries (with bound predicate arguments) to SQL, consistently yield query execution time that is comparable to that of SQL queries written directly for the relational representation of the data. The analysis further reveals the two optimizations are not uniquely required to achieve a successful wrapper system. The evidence suggests effective wrappers will be those that are designed to complement the optimizer of the target database.
COMMAND LIMITING IN RECONFIGURABLE FLIGHT CONTROL

Limits on the motion and on the rate of motion of the actuators driving the control surfaces of aircrafts significantly affect the performance of flight control systems. After a failure, the constraints become even more restrictive, because of the loss of control power and because of the increase in cross-couplin gs between the axes. In the paper, model reference adaptive control algorithms are considered for flight control reconfiguration and four methods are proposed to handle the problems arising due to actuator saturation. The methods are based on a scaling of the control inputs, a relaxation of the control requirements, a scaling of the reference inputs, and a least-squares approximation of the commanded accelerations. Simulations demonstrate the effectiveness of the methods for the control of a twin-engine fighter aircraft. It is found that even the simplest method considerably improves the responses compared to those obtained without modification. Further, despite the widely different concepts and complexity levels of the four methods of command limiting, the performance is found to be similar in most cases.
Forward-Speed Effects on Peripheral-Jet Ground Support Systems

This paper presents a theory for the effect of forward speed on a two-dimensional peripheral-jet ground-effect support. New analytical models are proposed for the flow at the peripheral-jet nozzle exit and the cross flow underneath the support. Results are presented for the lower-surface pressure distribution as well as the lift and ideal pumping power. The theory is supported by a comprehensive experimental study conducted with a two-dimensional model in a moving-ground wind tunnel. The model was externally fed and had a flat bottom. At low subcritical speeds, the effect of forward speed is found to be adverse in the absence of upper-surface lift. The theory predicts the freestream dynamic pressure to be less than the average cushion pressure for this model at critical speeds. At high subcritical speeds performance improved such that lift-power requirements at critical speeds are 20-30% below those at hover. Throughout the subcritical speed regime there is general agreement between theory and experiment. Although not considered in the present work the theory can be extended for a limited range above critical speed and to three-dimensional supports.
Comments on superstring interactions in a plane-wave background

The three string vertex for type-IIB superstrings in a maximally supersymmetric plane-wave background is investigated. Specifically, we derive a factorization theorem for the Neumann coefficients that generalizes a flat-space result that was obtained some 20 years ago. The resulting formula is used to explore the leading large mu asymptotic behavior, which is relevant for comparison with dual gauge theory results.
Square-planar Pd(II), Pt(II), and Au(III) terpyridine complexes: their syntheses, physical properties, supramolecular constructs, and biomedical activities.

5.1.2. Viscosity and Thermal Denaturation 1874 5.1.3. Induced Circular Dichroism 1875 5.1.4. Competitive Fluorescence Spectroscopy 1875 5.1.5. Closed Circular DNA 1876 5.1.6. Stereochemical Changes in DNA 1876 5.1.7. Site-Specific Intercalation 1877 5.1.8. Other Mononuclear Intercalators 1877 5.1.9. Multinuclear Intercalators 1878 5.2. Covalent Binding to Biomolecules 1881 5.3. Labeling Biomolecules 1882 5.4. Cytotoxicity 1885 5.4.1. Chemotherapeutic Agents 1886 5.4.2. Radiotherapeutic Agents 1892 6. Conclusion 1892 7. Acknowledgments 1892 8. References 1893
Towards a theoretical foundation for Laplacian-based manifold methods

In recent years manifold methods have attracted a considerable amount of attention in machine learning. However most algorithms in that class may be termed ''manifold-motivated'' as they lack any explicit theoretical guarantees. In this paper we take a step towards closing the gap between theory and practice for a class of Laplacian-based manifold methods. These methods utilize the graph Laplacian associated to a data set for a variety of applications in semi-supervised learning, clustering, data representation. We show that under certain conditions the graph Laplacian of a point cloud of data samples converges to the Laplace-Beltrami operator on the underlying manifold. Theorem 3.1 contains the first result showing convergence of a random graph Laplacian to the manifold Laplacian in the context of machine learning.
Spitzer IRAC Observations of White Dwarfs. I. Warm Dust at Metal-Rich Degenerates

This paper presents the results of a Spitzer IRAC 3-8 μm photometric search for warm dust orbiting 17 nearby, metal-rich white dwarfs, 15 of which apparently have hydrogen-dominated atmospheres (type DAZ). G166-58, G29-38, and GD 362 manifest excess emission in their IRAC fluxes and the latter two are known to harbor dust grains warm enough to radiate detectable emission at near-infrared wavelengths as short as 2 μm. Their IRAC fluxes display differences compatible with a relatively larger amount of cooler dust at GD 362. G166-58 is presently unique in that it appears to exhibit excess flux only at wavelengths longer than about 5 μm. Evidence is presented that this mid-infrared emission is most likely associated with the white dwarf, indicating that G166-58 bears circumstellar dust no warmer than -->T ~ 400 K. The remaining 14 targets reveal no reliable mid-infrared excess, indicating the majority of DAZ stars do not have warm debris disks sufficiently opaque to be detected by IRAC.
Vertical Drop Testing and Analysis of the Wasp Helicopter Skid Gear

Human occupant modeling and injury risk assessment have been identified as areas of research for improved prediction of rotorcraft crashworthiness within the NASA Aeronautics Program s Subsonic Rotary Wing Project. As part of this effort, an experimental program was conducted to assess the impact performance of a skid gear for use on the WASP kit-built helicopter, which is marketed by HeloWerks, Inc. of Hampton, Virginia. Test data from a drop test at an impact velocity of 8.4 feet-per-second were used to assess a finite element model of the skid gear test article. This assessment included human occupant analytic models developed for execution in LS-DYNA. The test article consisted of an aluminum skid gear mounted beneath a steel plate. A seating platform was attached to the upper surface of the steel plate, and two 95th percentile Hybrid III male Aerospace Anthropomorphic Test Devices (ATDs) were seated on the platform and secured using a four-point restraint system. The goal of the test-analysis correlation is to further the understanding of LS-DYNA ATD occupant models and responses in the vertical (or spinal) direction. By correlating human occupant experimental test data for a purely vertical impact with the LS-DYNA occupant responses, improved confidence in the use of these tools and better understanding of the limitations of the automotive-based occupant models for aerospace application can begin to be developed.
Occultation Searches for Kuiper Belt Objects

The occultation of background stellar sources by foreground Kuiper belt objects (KBOs) can be used to survey physical properties of the KBO population. We discuss statistics related to a KBO occultation survey, such as the event duration distribution, and suggest that occultation searches can be effectively used to probe the KBO size distribution below 10 km. In particular, we suggest that occultation surveys may be best suited to search for a turnover radius in the KBO size distribution because of collisions between small-size objects. For occultation surveys that monitor stellar sources near the ecliptic over a few square degrees, with time sampling intervals of the order of 0.1 s and sensitivity to flux variations of a few percent or more, a turnover radius between 0.1 and 1.0 km can be probed. While occultation surveys will probe the low-radius limit and imaging surveys will detect KBOs of size 100 km or more, statistics of objects with sizes in the intermediate range of around 1-100 km will likely remain unattainable.
A Simplified Method for the Preparation of Ethynyl P-Tolyl Sulfone and Ethynyl Phenyl Sulfone

Abstract Silica gel mediated desilylation of aryl 2-(trimethylsilyl)ethynyl sulfones was found to greatly simplify the synthesis of the acetylenic sulfones, ethynyl ptolyl sulfone 1 and ethynyl phenyl sulfone 2. Each were easily prepared in good yield and high purity on a multigram scale from bis(trimethylsilyl)acetylene 3.
Long-Term Performance of Multilaterals in Commingled Reservoirs

In this study. a comprehensive transient model was developed for multilateral wells producing from multiple formations separated by impervious streaks. The model is flexible and is capable of simulating the flow with any number of layers, unequal initial layer pressure, non-uniform petrophysical properties for each layer, and unequal layer size. Additionally. each lateral can have non-uniform formation damage and may be selectively completed. We investigated the long-term rate decline and cumulative recovery response of the multilateral wells connecting multiple isolated formations. Total flow rate, cumulative production, and fractional rate for each branch are all compared for several completion scenarios and layer properties. Crossflow between the layers through the wellbore is also evaluated.
The diffusion of gold in gamma uranium

Abstract The diffusion of gold in gamma uranium has been measured using a radioactive tracer and the sectioning technique. The values of D o and the activation energy are 4.86 × 10 −3 cm 2 /sec and 30 400 cal/mol respectively, fairly close to the values for self-diffusion in gamma uranium.
Synthesis of nickel sulfides in aqueous solutions using sodium dithionite.

Reaction of nickel chloride with sodium dithionite in aqueous solutions at ambient temperature has been investigated systematically to obtain nickel sulfides. The products are characterized by X-ray diffraction, thermogravimetric analysis, and electrical resistivity and magnetic susceptibility measurements. It is found that the compositions and structures of the products are controlled by the reaction pH and the amount of the reactants. While reactions under highly acidic (pH or = 7) conditions yield crystalline sulfur and amorphous or poorly crystalline NiySx, respectively, those at intermediate 3 < or = pH < or = 6 give crystalline NiySx. Both crystalline Ni3S2 (heazlewoodite structure) and Ni3S4 (spinel structure) have been obtained at room temperature. Additionally, NiS (millerite structure) is obtained by carefully heating Ni3S4 at 200 degrees C in a mixture of 90% Ar and 10% H2. Ni3S4 is found to be metastable, and it begins to disproportionate above 100 degrees C. Both Ni3S2 and Ni3S4 show metallic behavior. While Ni3S2 exhibits temperature-independent magnetic susceptibility, Ni3S4 shows ferrimagnetic ordering below 20 K.
Bladder Cancer Outcome and Subtype Classification by Gene Expression

Models of bladder tumor progression have suggested that genetic alterations may determine both phenotype and clinical course. We have applied expression microarray analysis to a divergent set of bladder tumors to further elucidate the course of disease progression and to classify tumors into more homogeneous and clinically relevant subgroups. cDNA microarrays containing 10,368 human gene elements were used to characterize the global gene expression patterns in 80 bladder tumors, 9 bladder cancer cell lines, and 3 normal bladder samples. Robust statistical approaches accounting for the multiple testing problem were used to identify differentially expressed genes. Unsupervised hierarchical clustering successfully separated the samples into two subgroups containing superficial (pTa and pT1) versus muscle-invasive (pT2-pT4) tumors. Supervised classification had a 90.5% success rate separating superficial from muscle-invasive tumors based on a limited subset of genes. Tumors could also be classified into transitional versus squamous subtypes (89% success rate) and good versus bad prognosis (78% success rate). The performance of our stage classifiers was confirmed in silico using data from an independent tumor set. Validation of differential expression was done using immunohistochemistry on tissue microarrays for cathepsin E, cyclin A2, and parathyroid hormone–related protein. Genes driving the separation between tumor subsets may prove to be important biomarkers for bladder cancer development and progression and eventually candidates for therapeutic targeting.
Harmonic superspace, minimal unitary representations and quasiconformal groups

We show that there is a remarkable connection between the harmonic superspace (HSS) formulation of N = 2, d = 4 supersymmetric quaternionic Kahler sigma models that couple to N = 2 supergravity and the minimal unitary representations of their isometry groups. In particular, for N = 2 sigma models with quaternionic symmetric target spaces of the form G/H × SU(2) we establish a one-to-one mapping between the Killing potentials that generate the isometry group G under Poisson brackets in the HSS formulation and the generators of the minimal unitary representation of G obtained by quantization of its geometric realization as a quasiconformal group. Quasiconformal extensions of U-duality groups of four dimensional N = 2, d = 4 Maxwell-Einstein supergravity theories (MESGT) had been proposed as spectrum generating symmetry groups earlier. We discuss some of the implications of our results, in particular, for the BPS black hole spectra of 4d N = 2 MESGTs.
Discussion of "Information distribution within firms: evidence from stock option exercises"

Abstract Huddart and Lang (J. Accounting Econom. 34 (2003)) documents that higher level of employee option exercise during a particular month is associated with lower returns in subsequent months, suggesting employees exploit private information in their exercise decisions. While the paper extends the insider trading literature that has focused on top executives, a number of inconsistencies with prior studies remain unresolved. Moreover, the study does not establish a direct link to the private information employees supposedly exploit. Establishing such a link is warranted here in the light of the surprising finding that exercises by senior employees are no more informative than those by lower rank employees.
Effects of an antiprogesterone (RU486) on the hypothalamic-hypophyseal-ovarian-endometrial axis during the luteal phase of the menstrual cycle

The impact of the antiprogesterone RU486 [17β hydroxy-11β-(4-dimethylaminophenyl)17α-(1-propynyl)estra-4,9-dien-3-one] on the hypothalamic-pituitary-ovarian-endometrial axis was examined in normal cycling women during the mid (MLP)- and late (LLP) luteal phases. During the MLP, 10 women received 3 mg/kg RU486 for 3 days. During the LLP, a single dose of 600 mg RU486 was administered to 4 women, and in another 4 women a single dose of 3 mg/kg was given during corpus luteum rescue by hCG. Longitudinal studies with daily and frequent blood samples (every 10 min for 10 h) were conducted during 3 consecutive cycles (control-treatment-recovery). During the MLP, RU486-induced uterine bleeding occurred in all 10 women 36–72 h after the first dose. No histological evidence of endometrial breakdown was found in endometrial biopsies taken 12–24 h before the onset of bleeding. Significant decreases in LH secretion (P < 0.001) and LH pulse amplitude (P < 0.006) and blunted pituitary responses to GnRH (P < 0.01) were e...
A simple flow reactor for transfer hydrogenation of olefins

Abstract A simple column reactor containing a small amount of palladium catalyst, in the form of palladium black, and formic acid as a hydrogen donorcan be used to hydrogenate several types of olefins.
Neutron Stars as X-ray Sources

DURING the rocket flight reported in the preceding communication, Bowyer et al. found two celestial X-ray sources with diameters less than 5°. One was located in the northern part of Scorpius in a region of faint stars but devoid of visible nebulosity and radio objects, while the other was coincident with the Crab Nebula, the well-known source of optical and radio synchrotron emission.
Single-stage-to-orbit — Meeting the challenge

Abstract There has been and continues to be significant discussion about the viability of fully reusable, single-stage-to-orbit (SSTO) concepts for delivery of payloads to orbit. Often, these discussions have focused in detail on performance and technology requirements relating to the technical feasibility of the concept, with only broad generalizations on how the SSTO will achieve its economic goals of greatly reduced vehicle ground and flight operations costs. With the current industry and NASA Reusable Launch Vehicle Technology Program efforts underway to mature and demonstrate technologies leading to a viable commercial launch system that also satisfies national needs, achieving acceptable recurring costs becomes a significant challenge. This paper reviews the current status of the Reusable Launch Vehicle Technology Program including the DC-XA, X-33, X-34 flight systems and associated technology programs. The paper also examines lessons learned from the recently completed DC-X reusable rocket demonstrator program. It examines how these technologies and flight systems address the technical and operability challenges of SSTO whose solutions are necessary to reduce costs. The paper also discusses the management and operational approaches that address the challenge of a new cost-effective, reusable launch vehicle system.
An improved vinylalumination procedure replacing HMPA with NMO for the hydroalumination of α-acetylenic esters and ketones

Replacing carcinogenic HMPA with NMO, a higher yielding, enviornmentally benign procedure for the vinylalumination of carbonyl compounds with [α-(ethoxycarbonyl)- vinyl]diisobutylaluminium and its β-methyl or -phenyl analogs, as well as [α-(acetyl)vinyl]diisobutylaluminium has been developed.
Using an emissive uridine analogue for assembling fluorescent HIV-1 TAR constructs

Emissive nucleoside analogues that are sensitive to their microenvironment can serve as probes for exploring RNA folding and recognition. We have previously described the synthesis of an environmentally sensitive furan-containing uridine and its triphosphate, and have demonstrated that T7 RNA polymerase recognizes this modified ribonucleoside triphosphate as a substrate in in vitro transcription reactions. Here we report the enzymatic preparation of fluorescently tagged HIV-1 TAR constructs and study their interactions with a Tat peptide. Two extreme labeling protocols are examined, where either all native uridine residues are replaced with the corresponding modified fluorescent analogue, or only key residues are site-specifically modified. For the HIV-1 Tat-TAR system, labeling all native uridine residues resulted in relatively small changes in emission upon increasing concentrations of the Tat peptide. In contrast, when the two bulge U residues were site-specifically labeled, a reasonable fluorescence response was observed upon Tat titration. The scope and limitations of such fluorescently tagged RNA systems are discussed.
Spectrum Allocation for Time-varying Traffic in Elastic Optical Networks using Traffic Pattern

We propose sub-carrier allocation algorithms for time-varying traffic in Elastic Optical Networks using similar patterns of Internet traffic. These algorithms achieve lower blocking probability and minimize number of disruptions to the live connections.
The Multilingual Subject

This book explores the experience of adolescents and young adults who learn a foreign language or use more than one language in daily life. Through ‘language memoirs’ and learners’ testimonies, it documents how these multilingual subjects occupy an embodied, socially and culturally inflected third place in language, filled with memories of other languages and fantasies of other identities. In its referential and mythic dimensions, language performs and creates subjectivities that these multilingual speakers use to conjure alternative worlds and virtual selves, both in real life and on the internet. Teaching to the multilingual subject would mean capitalizing on the potential playfulness, heightened reflexivity and aesthetic sensibility of the increasing number of people around the world who, by choice or necessity, experience life in several languages.
CAD/CAM and New Design Technologies in High Energy Physics Electronics Applications

In the past few years, several significant new technologies related to electronics design, fabrication and testing, appear to have reached a level of maturity which makes them ripe for exploitation by high energy physics laboratories. This paper will review recent developments and trends, and will draw particularly from some examples at Stanford Linear Accelerator Center. Cost benefits as well as difficulties of implementing new technologies into relatively small laboratories will be examined.
Diffuse Interstellar Band Formation in Dense Clouds

Measurements of the strengths of the diffuse interstellar bands at 4430, 5780 and 5797 A show that the bands tend to be weak with respect to extinction in dense interstellar clouds. Data on 10 stars in the Q Ophiuchi cloud complex show further that the diffuse band-producing efficiency of the grains decreases systematically with increasing grain size. It is concluded that the diffuse bands are not formed in the mantles which accrete on the grains in interstellar clouds, but that they could be produced in the cores of grains or in some molecular species.
The VIVACE Converter: Model Tests at High Damping and Reynolds Number Around 105

The vortex induced vibrations for aquatic clean energy (VIVACE) converter is a new concept to generate clean and renewable energy from fluid flows such as those abundant in oceans, rivers, or other water resources. The underlying concepts for design, scaling, and operation of VIVACE were introduced in Bernitsas et al., 2008, "VIVACE (Vortex Induced Vibration Aquatic Clean Energy): A New Concept in Generation of Clean and Renewable Energy From Fluid Flow," ASME J. Offshore Mech. Arct. Eng., 130(4), p. 041101. In its simplest form, a VIVACE modulo consists of a single rigid cylinder mounted on elastic supports and connected to a power takeoff (PTO) system. The cylinder is placed in a steady unidirectional current and excited in vortex induced vibration (VIV). In this paper, the VIVACE modulo was tested in the Low Turbulence Free-Surface Water Channel of the University of Michigan to demonstrate the concept, generate electricity, measure the power out, and calculate basic benchmarking measures such as energy density. The tests performed were tailored to the particulars of the VIVACE modulo, which dictate that the cylinder operate in VIV under high damping and as high a Reynolds number as possible. At the same time, a broad range of synchronization is required to make VIVACE effective in energy generation in a realistic environment. Due to these requirements, VIV tests have not been performed before in the subspace applicable to the operation of the VIVACE modulo. In the process of extracting fluid kinetic energy and converting it to electricity in the laboratory, for a given set of cylinder-springs-transmission-generator, only the damping used for harnessing electricity was optimized. Even at this early stage of development, for the tested VIVACE modulo, the maximum peak power achieved was P peak =0.308×1 2ρDLL. The corresponding integrated power in that particular test was P VIVACE =0.22×1 2ρU 3 DL with theoretical upper limit based on measurements of P UL-VIVACE =0.3663. Such power was achieved at velocity U=0.840 mis =1.63 Kn.
Terrorism, the Use of Force and International Law after 11 September

There were at least four possible legal justifications for the use of force against Afghanistan: Chapter VII of the UN Charter, intervention by invitation, humanitarian intervention and self-defenc...