Miracle-dz/UniFAR-FTUs huggingface dataset:
Analysis of a class of optimal control problems arising in cancer chemotherapy

A class of mathematical models for cancer chemotherapy take the form of an optimal control problem over a fixed horizon with dynamics given by a bilinear system and objective linear in the control. In this paper we give results on local optimality of controls for both a two- and three-dimensional model. The main control in both models is a killing agent which is active during cell-division. The three-dimensional model also considers a blocking agent which slows down the growth of the cells during synthesis. The cumulative effect of the killing agent is used to model the negative effect of the treatment on healthy cells. It is shown that singular controls are not optimal for these models and optimality properties of bang-bang controls are established. Specifically, transversality conditions at the switching surfaces are derived which in a nondegenerate setting guarantee the local optimality of the flow if satisfied while they eliminate optimality of the trajectories if violated.
Vibratory power transmission through coupled composite plates with joint compliance and damping

This paper presents a wave-based, analytical method for the computation of power transfer coefficients (PTC) to evaluate vibratory power transmitted through a set of angled structural joints that connects an arbitrary number of composite plates. Each joint is only used to hold two adjacent plates together. The elastic wave motions and dispersion properties of the plate are calculated by considering shear deformation, rotary inertia, and material anisotropy. The joint is modeled with stiffness and damping in both translational and rotational directions, and the joint parameters are allowed to differ from one joint to another. The equilibrium conditions at the joint set are derived to solve for the complex amplitude of waves propagating away from it. From the PTCs computed for a particular angle of wave incidence at the junction, the diffuse-field PTCs are calculated using weighted integral of the incidence angle. A comparison with published numerical results for simpler configurations has been performed in order to validate some key aspects of the present analytical formulation. Several numerical examples of two coupled composite sandwich panels are considered to compute PTCs, through which it is clearly demonstrated that the joint compliance and damping as well as the transverse shear deformation and rotary inertia of composite sandwich panels influence the vibratory power transmission through coupled composite plates.
The Magnetohydrodynamics of Umbral Flux Tubes. II. Spectroscopic Properties

We apply a recently developed magnetohydrodynamic model for flux tube systems within sunspot umbrae for a range of model parameters appropriate to umbral dots. The results are used to generate synthetic observations of umbral dots, which we then compare to recent observational data taken from the literature. Below the umbral surface, our umbral flux tube models are characterized by (1) reduced (but nonzero) field strength relative to the surrounding umbra, (2) a relative temperature enhancement, and (3) an assumed upflow which advects heat toward the surface, thus making the dot brighter than its surroundings
Longitudinal and transverse structure functions in a turbulent round jet: effect of initial conditions and Reynolds number

The difference between scaling exponents of longitudinal and transverse velocity structure functions in the far-field of a round jet is found to depend on the anisotropy of the flow. The effect of the large-scale anisotropy is assessed by considering different initial conditions at the jet nozzle, and hence different ratios of the longitudinal to transverse rms velocities. The effect of the Taylor microscale Reynolds number on the small scale anisotropy is also considered. Both effects account, to a large extent, for the observed difference between longitudinal and transverse exponents and the disagreement between previously published results of different authors. This disagreement also depends on the method used to determine the inertial range. An empirical description of the overall behaviour of the structure functions provides reasonable estimates for the longitudinal and transverse exponents, accounting reasonably well for the anisotropy of both large- and small-scale motions.
The Real-Time Mesoscale Analysis at NOAA’s National Centers for Environmental Prediction: Current Status and Development

AbstractIn 2006, the National Centers for Environmental Prediction (NCEP) implemented the Real-Time Mesoscale Analysis (RTMA) in collaboration with the Earth System Research Laboratory and the National Environmental, Satellite, and Data Information Service (NESDIS). In this work, a description of the RTMA applied to the 5-km resolution conterminous U.S. grid of the National Digital Forecast Database is given. Its two-dimensional variational data assimilation (2DVAR) component used to analyze near-surface observations is described in detail, and a brief discussion of the remapping of the NCEP stage II quantitative precipitation amount and NESDIS Geostationary Operational Environmental Satellite (GOES) sounder effective cloud amount to the 5-km grid is offered. Terrain-following background error covariances are used with the 2DVAR approach, which produces gridded fields of 2-m temperature, 2-m specific humidity, 2-m dewpoint, 10-m U and V wind components, and surface pressure. The estimate of the analysis u.
Effects of surfactant on droplet spreading

The effects of surfactant and temperature on the spreading of a viscous droplet are studied. Lubrication theory is used to develop a model for the evolution of the droplet. The surfactant is assumed to be insoluble and transport onto and off of the droplet interface at the contact line is allowed. A linear temperature gradient plus a gradient in the surface energy are allowed along the substrate. We find that these effects together can increase the speed of the translation of the droplet. We also find that allowing the static contact angle to vary with the surfactant concentration and temperature, as described by Young’s law, can speed up droplet motion. When contact angle hysteresis is allowed, it is possible for the droplet to stop moving when surfactant transport is allowed along the interface.
The Relationship between Fractional Coverage of High Cloud and Rainfall Accumulations during GATE over the B-Scale Array

Abstract A description is given of the relationship between 6 h averages of fractional coverage of cloud above various height and temperature thresholds, derived from infrared data from the Synchronous Meteorological Satellite 1 (SMS 1), and accumulated rainfall, derived from data obtained with a group of quantitative C-band digital radars. Comparisons are made over a hexagonal area extending from 22.25–24.75°W longitude and from 7–10°N latitude (the B-scale array) for each phase of the GARP Atlantic Tropical Experiment (GATE). Scattergrams of fractional coverage above 10 km, the altitude of maximum correlation, show a linear relationship for each phase, with correlations ranging from 0.81 to 0.89. Reanalysis of Phase I, omitting a single outlier, results in a very narrow range for the regression coefficients for all three phases. An analysis of the pooled data from all three phases, omitting the single outlier, shows that 75% of the variance in 6 h rainfall accumulations over the GATE B-scale array is ex.
A Common Origin for Organics in Meteorites and Comets: Was It Interstellar?

Abstract The insoluble organic material preserved in primitive chondritic meteorites shares many similarities with the refractory organic material in interplanetary dust particles and comets, suggesting that there is a genetic link between the organic matter in objects that formed between ~3 AU and ~30 AU from the Sun. These similarities include large D and 15N enrichments in bulk and even more extreme enrichments in isotopic hotspots. The enrichments attest to formation in very cold environments, either in the outer Solar System or the protosolar molecular cloud. There are many properties of this organic material that are consistent with an interstellar origin, but a Solar System origin cannot be ruled out. Similar organic material is presumably an important component of most protoplanetary disks, and heating or sputtering of this material would be a source of PAHs in disks. The soluble organic matter was more heavily effected by processes on the chondritic parent bodies than the insoluble material. Amino acids, for instance, probably formed by reaction of ketones and aldehydes with NH3 and HCN. The accretion of the relatively volatile NH3 and HCN, presumably in ices, strengthens the chondrite-comet connection. However, unlike most comets the water in chondrites, when it was accreted, had D/H ratios that were similar to or depleted relative to Earth.
Characterisation of plane regions that support quasiconformal mappings to their domes

We prove that the nearest point retraction of a region P, not the whole plane, to its dome is long‐range bilipschitz if and only if P is uniformly perfect. From this we prove that P uniformly perfect is necessary and sufficient for the existence of a K‐quasiconformal map from P to its dome which extends to be the identity on the boundary and is finite distance to the nearest point retraction. Thus our work extends the classic theorem of Sullivan for simply‐connected regions to regions of arbitrary connectivity. In particular, our study results in a simple, transparent proof of the original theorem.
Discharge formation processes and glow-to-arc transition in pseudospark switch

Deals with an interpretation of the current sustaining mechanisms at different stages of the high-current low pressure pulsed gas discharge with hollow cathode (pseudospark discharge). The analysis of experimental data for the stage of delay time to breakdown and the subsequent stages is presented. The principal features of glow stages are interpreted in the framework of the concept of nonmonotonic potential distribution in the near cathode regions. It is shown that in spite of extremely high current density the main fraction of the discharge current at the cathode surface is carried by the ion component. In the superdense glow stage the ion current is provided due to numerous microexplosions of the cathode surface, ionization of the metal vapor inside the cathode voltage drop region, and returning the metal vapor back to the cathode in a form of ions. The glow mode in this case is determined by a uniform distribution of the explosion centers over the cathode.
Enhancing online waveform processing by adding new point attributes

RIEGL LIDAR instruments based on echo digitization and on-line waveform processing provide valuable attributes to every detected target: calibrated amplitude, calibrated estimated target reflectance, and echo pulse deviation. Additional attributes could be provided by employing enhanced algorithms. In hydrography an estimate for the backscattering coefficient of a water column, for topographic targets an estimate of the angle of incidence of the laser beam on flat targets can be determined. We present data sets based on on-line waveform processing of RIEGL's V-Line and assess the possibility of deriving additional attributes by performing more sophisticated analysis of the waveform.
Broadband energy-harvesting using a two degree-of-freedom vibrating body

In this letter, we introduce the concept and describe the realization of a two degree-of-freedom piezoelectric energy-harvesting device. The proposed system consists of a proof mass (i.e., a rigid body) and two cantilever beams; it can utilize both translational and rotational degrees of freedom. Therefore, it exhibits double power peaks and an increased frequency bandwidth, and it can generate power more efficiently than conventional vibration-based single degree-of-freedom devices.
How is turbulent energy dissipated in a superfluid?

At a sufficiently large Reynolds number the flow of a classical fluid becomes turbulent. Typically, turbulent energy is injected into large-scale eddies, from which it flows through the action of the non-linear term in the Navier–Stokes equation into smaller and smaller eddies until the scale of the motion is small enough that the energy can be dissipated by viscosity. In a superfluid (liquid 4He or liquid 3He), which has no viscosity, this source of dissipation is absent, so that perhaps the flow of turbulent energy persists down to atomic scales; furthermore, the absence of viscosity seems to imply that the Reynolds number is infinite. However, turbulent motion in a superfluid is restricted by quantum effects, associated with the quantization of angular momentum, and it will be shown how these effects change this picture and lead to an effectively finite Reynolds number, with dissipation that mimics the effect of viscosity and arises from the radiation of sound by special types of quantized motion.
Vector normal modes on two-core optical fibers. II. The modal cutoffs

For pt.I see ibid., vol.15, no.7, p.1213-24 (1997). A vector theory based on generalization of the circular harmonics expansion method combined with the finite-element method is formulated to determine cutoff values for higher-order normal modes on the two-core fiber with radially inhomogeneous core index profiles. The method is developed under the transverse magnetic field formulation in order to avoid the spurious solutions. Numerical examples are given for the two-identical-core cases with power-law core index profiles.
Uniform mean scalar gradient in grid turbulence: Conditioned dissipation and production

The equation for the one‐point probability distribution function (pdf), P(φ), of a passive scalar in incompressible turbulence contains two statistical functions, both conditioned on scalar value. The first is the much‐studied (in homogeneous flows) conditioned expected value of scalar dissipation, χ, the second is the conditioned expected value of the velocity vector. Recent measurements in the grid configuration have shown that the tails of the scalar pdf are exponential rather than Gaussian and that χ is U shaped. For this field, χ has been solved for by assuming two forms of P(φ,x) (Gaussian and exponential) and taking the pdf of the velocity conditioned on φ to be normal. The solutions χg and χe are shown to be similar in form, both U shaped, when the scalar (normalized by its variance)≤10. Comparison with experimental data confirms that advection by the mean velocity and production are dominant terms affecting the shape of χ. Gaussianity of P(φ,x) is not a sufficient condition for χ to be flat i.
An infrared study of Orion Molecular Cloud-2 (OMC-2)

This paper reports 1.2-23 micron photometry for 11 discrete sources in Orion Molecular Cloud-2 (OMC-2). These data, combined with H and K photometric and K polarimetric images, are used to model the cluster sources. Most appear to be young stars of roughly solar mass. Some have circumstellar dust reradiation or reflection nebulosity. A model based on single scattering of light from an exciting star explains some features of the IRS 1 nebula, the largest reflection nebula in OMC-2. However, the red colors and high surface brightness of the IRS 1 nebula require a cool excitation source that is more luminous than far-infrared observations would indicate. 34 refs.
Baroclinic instability of semi‐geostrophic fronts with uniform potential vorticity. I: An analytic solution

Baroclinic instability of uniform potential‐vorticity flow between solid upper and lower boundaries is analysed. The instability is driven by meridional temperature gradients on the boundaries. The classic Eady model of baroclinic instability uses just this system with the further idealization that the temperature gradients in the basic state are uniform. Here, this last idealization will be replaced with a complementary one in which the basic‐state temperature gradients are taken to be concentrated in a front. The analysis then takes advantage of the fact that the boundary temperature anomalies created by the growing baroclinic wave are localized at the front. The dependence of the growth rates and phase structure on wave number are remarkably similar to those of the Eady model. The wave number of maximum instability and the short‐wave cut‐off differ from those of the Eady model by less than 2% and 10% respectively. The solution is asymptotic in the limit of zero frontal width in geostrophic coordinates. For a physical flow this limit can never be achieved, but comparison with direct numerical solutions shows that the analytic solution is still accurate at physically relevant frontal widths. Part I develops the solution based on an equation for the evolution of the displacement of the surface and upper fronts. Part II will look at the three‐dimensional structure of the disturbance in more detail.
The application of the quasi-geostrophic Eliassen-Palm flux to the analysis of stratospheric data

Abstract The quasi-geostrophic form of the Eliassen-Palm flux is calculated for steady linear planetary wave 1 in a realistic zonal flow with dissipation. This flux shows a region of divergence in the polar stratosphere that is similar to that found in time averages of observations. Comparison with the full primitive equation form of the Eliassen-Palm flux indicates that in the model this divergent region is spurious and results from the overestimation of the momentum flux divergence when it is calculated from geostrophic winds. An approximate expression for the Eliassen-Paim flux in terms of balanced winds is suggested as an alternative to the quasi-geostrophic form.
Time-resolved diffraction measurements of electric-field-induced strain in tetragonal lead zirconate titanate

The dynamic electric-field-induced strain in piezoelectric ceramics enables their use in a broad range of sensor, actuator, and electronic devices. In piezoelectric ceramics which are also ferroelectric, this macroscopic strain is comprised of both intrinsic (piezoelectric) and extrinsic (non-180° domain switching) strain components. Extrinsic contributions are accompanied by hysteresis, nonlinearity, and fatigue. Though technologically significant, direct measurement of these mechanisms and their relative contributions to the macroscopic response has not yet been achieved at driving frequencies of interest. Here we report measurements of these mechanisms in ceramic lead zirconate titanate during application of subcoercive cyclic driving electric fields using an in-situ stroboscopic neutron diffraction technique. Calculations are made from the diffraction measurements to determine the relative contributions of these different strain mechanisms. During applied electric field square waves of +0.5Ec unipolar.
Exponential Approximations for Two Classes of Aging Distributions.

Abstract : If a random variable is exponentially distributed with microns = EX and microns 2 = EX2, then microns 2 = 2 microns squared. Defining rho determinant u(2)/2 micron squared minus 1, it is tempting to conjecture that under mild restrictions a distribution with small rho is approximately exponential. That restrictions are needed is seen by the example, Pr(X = 0) = Pr(X - 1) = 1/2, for which rho = 0. The scale invariant quantity, rho, was suggested by Keilson. It has an interesting interpretation. Define G(x) = micron 1/minus x integral (x,0)/minus negative F (s)ds, the stationary renewal distribution corresponding to F. Then microns G = microns 2/2 microns and rho = determinant micron(G)/micron minus 1. The parameter rho is thus the scaled (by micron) distance between micron and micron G. For F exponential, F = G and thus micron = micron G.
Bloch modes of optical fishnets

From a microscopic point of view, we theoretically investigate fishnet metamaterials. We formulate the construction of the fundamental Bloch mode by tracking the flows of energy through the fishnet structure. The analysis is supported by a closed-form semi-analytical model based on surface-plasmon coupled-mode equations. The model provides an accurate formula for the fishnet refractive index, including the real (negative-valued) and imaginary parts. The model simply explains how the surface plasmon modes couple in the structure and it shines new light on the fishnet negative-index paradigm at optical frequencies. It possesses broad flexibility in geometrical and material parameter tailoring of fishnet properties, even including the gain-assisted case.
Detrainment from a turbulent plume produced by a vertical line source of buoyancy in a confined, ventilated space

Abstract New experiments are presented which explore the dynamics of a turbulent buoyant plume produced by a vertically distributed linear source of buoyancy of strength $f$ per unit height. In a uniform environment, the plume volume flux increases with height from the base of the source, $z$ , as $q(z) = {2^{-1/3}} {\pi }^{2/3} \alpha ^{4/3} f^{1/3} z^2$ where the entrainment coefficient, $\alpha = 0.09\pm 0.01$ . In an enclosed space, with a net upward vertical ventilation flow $Q_V$ , the buoyant plume generates a steady ambient stratification. The lowest part of the space, $zh_i$ , the ambient fluid is linearly stratified with a reduced gravity gradient $f/Q_V$ , and has no net vertical motion. Instead, for $z>h_i$ , the time-averaged volume flux in the plume equals the ventilation flow. The intermittent entrainment of ambient fluid into the plume is now matched by intermittent detrainment from the plume, and the mean buoyancy in the plume relative to the ambient remains constant. The supply of fresh ventilation fluid to the ambient in the linearly stratified zone only occurs through the local detrainment and consequent horizontal intrusion of fluid from the plume. This has key implications for design of ventilation systems, in which there may be vertically distributed sources of buoyancy.
Are Prohibitions of Superluminal Causation by Stochastic Einstein Locality and by Absence of Lewisian Probabilistic Counterfactual Causality Equivalent?

Butterfield's (1992a,b,c) claim of the equivalence of absence of Lewisian probabilistic counterfactual causality (LC) to Hellman's stochastic Einstein locality (SEL) is questioned. Butterfield's assumption on which the proof of his claim is based would suffice to prove that SEL implies absence of LC also for appropriately given versions of these notions in algebraic quantum field theory, but the assumption is not an admissible one. The conclusion must be that the relation of SEL and absence of LC is open, and that they may be independent.
An Investigation of the Visual-Mental Capability of Pre- and In-Service Mathematics Teachers: A Tale of Two Cones and One Cube

This study investigated the visual-mental capabilityof pre-service and in-service mathematics teachers as well as academicians making a career change to mathematics teachers with regard to manipulations of two geometric shapes (from 2- to 3-dimensional). Moreover, it investigated whether there are differences between the visual-mental capabilityof these participant groups. Findings illustrate that most of the participants demonstrate an adequate visual capability relating to the task dealing with a cube. Conversely, very low percentage of participants manifested a visual-mental capability in a task requiring the identification of a solid resulting from rotation of a square page, whose diagonal serves as the rotation axis. The study indicates that learners’ high visual view should be developed in order to enhancetheir visual-mental capability.