Parallel Straight Lines Research Articles

A new approach for the determination of anaerobic threshold: methodological survey on the modified Dmax method

A wide variety of diagnostic techniques can be found in the literature for anaerobic threshold (AT) assessment. The aim of this study was to investigate if the heart rate (HR) at the modified D max method (Mod-D max ) using parallel straight line slope (PSLS) mathematical model and the Narita target heart rate equation was comparable with the HR measured at the AT by the continuous respiratory gas measurements in healthy young girls. Eight (age 19.29±1.70 years) healthy young girls performed an exhaustive treadmill exercise test for determination of the HR at Mod-D max using PSLS model and Narita equation. The AT of the participants was also calculated by the continuous respiratory gas measurements according to the Craig method. There was no significant difference between the HR determined at the Mod-D max method and the HR measured at the AT by the continuous respiratory gas measurements (167±9.22 vs. 165.25±6.32 b/min). Bland and Altman plots revealed a good agreement between the determined HR at Mod-D max and values of the HR measured at the AT by the continuous respiratory gas measurements (95% CI =−20 to+22.8 b/min). According to the results, the Mod-D max using PSLS model and the Narita equation during the exhaustive treadmill exercise test is an accurate and reliable noninvasive alternative to the cumbersome, expensive, and time-consuming invasive methods. Therefore, the Mod-D max method can be used for the determination of AT in healthy young girls.

EFFICIENT EVALUATION OF THE LONGITUDINAL COUPLING IMPEDANCE OF A PLANE STRIP

We discuss the electromagnetic interaction between a traveling charge particle and a perfectly conducting strip of a negligible thickness. The particle travels at a constant velocity along a straight line parallel to the axis of symmetry of the strip. The e-ciency of the proposed solution is proved by evaluating the longitudinal coupling impedance in a wide range of parameters.

Binding of diuretic antihypertensive bendroflumethiazide to human serum albumin studied by 19F nuclear magnetic resonance method

Simultaneous specific and nonspecific binding of bendroflumethiazide (BFZ) to human serum albumin (HSA) and concentration profile of BFZ in HSA buffer (pH 7.40) solution were investigated by 19F nuclear magnetic resonance (NMR) method. The 19F NMR spectrum of BFZ (200 μM) in a buffer solution showed a sharp signal of its CF 3 group at 17.8 ppm from the reference trifluoroethanol. Addition of 0.60 mM HSA to the sample solution caused the CF 3 signal splitting into three broadened peaks at 18.4 (A), 17.9 (B) and 17.4 ppm (C). By its chemical shift and spectral behavior, B was assigned to unbound BFZ. Competition experiments with Site I and II ligands lead to C being assigned to Site II bound BFZ. However, the peak intensity (areas) of A was not reduced by these ligands, suggesting that A arises from nonspecific binding. Using the peak intensities at several total concentrations of BFZ, Scatchard plot was performed. The plot for A provided a straight line parallel to the x-axis confirming nonspecific binding and that for C was consistent with specific binding. The binding constants for nonspecific and specific Site II binding were 1.02 and 1.00 × 10 4 (M −1) ( n = 1.1), respectively. The presence of 0.10 M Cl − in the sample solution affected the binding constant of Site II binding, but not that of nonspecific binding. The concentration profile of BFZ calculated using the binding constants revealed that nonspecific binding is more effective than Site II binding for the binding of BFZ to HSA. It was also confirmed that considerable amounts of BFZ liberated from Site II by the Site II ligands or Cl − ions bind again nonspecifically.

Particle size, porosity and temperature effects on char conversion

The effect of particle size, porosity and reactor temperature/reaction rate constant on the progress of a char particle conversion has been investigated numerically by solving the transport equation inside a reacting char particle. Numerical simulations have been conducted for three cases that include two extreme cases and one general case. The two extreme cases correspond to a very large Damkohler number (3.2607 × 10 3) and a very small Damkohler number (0.0042). The third case corresponds to an intermediate value of Damkohler number. For the very large Damkohler number case, concentration profiles of the gasifying agent showed a steep gradient across the particle and the reaction occurred mostly in outer layer of the particle. This behavior corresponds to a diffusion controlled process. For the very small Damkohler number case, gasifying agent concentration was a straight line parallel to the x-axis, with a y-axis value of the surrounding concentration. The reaction occurred homogeneously across the particle and the degree of conversion was only a function in time. This behavior corresponds to a chemically controlled process. The total conversion of the char particle as a function of time has also been calculated for different particle sizes, initial porosity and reaction rate constant. Variation in conversion profiles as a function of time due to variation in initial porosity and reaction rate constant were limited to a certain extent. Very high initial porosity values tend to shift the process towards a chemically controlled one; any further increase in porosity does not have a positive effect on the conversion–time relationship. Very high reaction rate constants tend to shift the process towards diffusion controlled process. Kinetic parameters have been determined experimentally using a chemically controlled process. The obtained parameters have been used in the model to determine the progress of char particle conversion at an increased reactor temperature of 1000 °C. The model has been compared to experimental results at the same temperature (1000 °C). The results showed very good agreement.

Classification of regular circle three-webs up to circular transformations

A curvilinear three-web formed by three pencils of circles is called a circle web. Generally speaking, the circle three-web is not regular, i.e., it is not locally diffeomorphic to a web formed by three families of parallel straight lines. In this paper, all regular circle three-webs are classified up to circular transformations. The main result is as follows: There exist 48 nonequivalent (with respect to circular transformations) types of regular three-webs. Five of them contain ∞3 nonequivalent webs each, 11 types contain ∞2 nonequivalent webs each, and 12 types contain ∞1 nonequivalent webs each; 5 webs admit a one-parameter group of automorphisms.

Sense and sign in wave and crystal dislocations

Dislocations in waves and in crystals are compared, in tutorial style, withparticular emphasis on signs and senses. Reconnection of dislocations and thedisappearance of a closed loop are treated as examples. There is a fundamentaldifference between the regularized phase gradient of a wave dislocation or wavevortex, as defined in a recent paper, and the Burgers vector of a dislocation in acrystal; the latter, as is well known, is not strictly a vector at all, because, todefine it, a sense of direction for the dislocation line has to be chosen arbitrarily.The Burgers vector in a crystal is more analogous to the phase circulation of ± 2π around a wave dislocation. The new vector now associated with a wave dislocation could becalled, not the Burgers vector, but simply ‘the phase gradient vector’. A new result is to seethat, by an isotropic scaling, two parallel straight dislocation lines of opposite sign haveidentical phase patterns in the plane normal to them, regardless of whether they are of pureedge, or mixed edge/screw type.

Inter-relationships between solubilities, distribution coefficients and melting points of some substituted benzoic and phenylacetic acids.

Ten 4-hydroxy and 4-alkoxy benzoic and phenylalkanoic acids have been investigated. Solubilities in aqueous buffer at pH 1.2 were determined, together with distribution coefficients between the buffer and either octanol or isopropyl myristate. When plotted against the total number of carbon atoms in the side chains, log octanol/water distribution coefficients gave two parallel straight lines, one for the substituted benzoic acids, and the other for the substituted phenylalkanoic acids. The slopes approximated to 0.5, the generally accepted value for methylene. Similar plots could be obtained with isopropyl myristate, provided the hydroxy acid results were ignored, and also when log aqueous solubilities were plotted against carbon number, although there was considerable scatter. The differences between the distribution coefficient results were explained in terms of solute-solvent interactions, and the scatter attributed to variations in the heats of fusion of the solutes. Yalkowsky's equation (1977), linking aqueous solubilities and melting points with distribution coefficients, was applied to the results, and found to be of limited predictive value.

A free boundary problem for p-Laplacian in the plane

We consider the following free boundary problem in an unbounded domain Ω in two dimensions: Δ p u = 0 in Ω, u = 0 , ∂ u ∂ n = g 0 on J 0 , u = 1 , ∂ u ∂ n = g 1 on J 1 , where ∂ Ω = J 0 ∪ J 1 . We prove that if 0 < u < 1 in Ω, J i is the graph of a function in C loc 1 , α ( R ) and g i is a constant for each i = 0 , 1 , then the free boundary ∂ Ω must be two parallel straight lines and the solution u must be a linear function. The proof is based on maximum principle.

Growth of CuO and CuGaO2 Thin Films by Spin-coating Method

ABSTRACTCuO and CuGaO2 thin films have been grown on Si (100) substrates using a sol-gel spincoating method. CuO films were successfully fabricated by the annealing around 700°C. At higher temperatures (&gt;800°C), pyramidal CuO islands with 1~2μm in width and 0.4~0.8μm in height were observed. They arranged structures as a straight line parallel to the &lt;110&gt; and &lt;010&gt; directions, which suggests the self-organized growth of CuO pyramidal islands. Delafossite CuGaO2 films were fabricated as well, using Cu-Ga-O mixed solutions with Ga/(Cu+Ga) atomic ratio of 0.5. These results indicate that Cu-based compounds were fabricated by the sol-gel spincoating method.

Color constancy from invariant wavelength ratios. II. The nonspectral and global mechanisms

AbstractGiven the spectral mechanism of color constancy (Part I of this series), the remaining nonspectral mechanism is formulated here in Part II by the constraint of correlation with known spectral illuminant–invariant functions, i.e., invariant wavelength ratios between constant hues, which plot straight parallel lines in the plane of wavelength and reciprocal illuminant color temperature (MK−1). The same is assumed to apply to nonspectral constant hues in the same plane and dominant wavelength scale extended to cover the nonspectrals (see accompanying article “Relative wavelength metric for the complete hue cycle …”). To simplify analysis, stimuli are optimal aperture colors; their monochromatic stimuli lie between 442 and 613 nm, common boundaries with optimal compound stimuli (nonspectrals). It is shown that the wavelengths and invariant ratios of spectral constant hues can be formulated exactly (±0.5%) from the ratios of an harmonic period, which shifts wavelength with MK−1. The formula implies this color‐constant hue cycle is isomorphic across illuminants and allows prediction of nonspectral constant hues. To identify these colorimetrically, their spectral complementary wavelengths are specified for various illuminants. This completes theglobal color constancy mechanism for the illuminant color temperature range 2800 to 25,000 K. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2010

On the bisection operation

For two perceived sensory magnitudes, A and B, the bisection operation yields a perceived sensory magnitude, C, equally different from A and B. Available data do not resolve whether this operation is equivalent to a linear or a nonlinear mean. We tested these alternatives, using the evidence of functional measurement research that ratings are linear sensory measures. With A and B varied factorially, linear means predict that the curves relating rated C to rated A for each B are parallel straight lines, and nonlinear means predict that these curves are nonlinear and nonparallel. Using brightness and perceived size as sensory attributes, the present experiments confirm the first of these predictions, indicating that the bisection operation is equivalent to a linear mean.

Allophane films formed at the liquid/liquid interface

Allophane films were formed at the liquid/liquid interface between water and carbon tetrachloride. The microstructure of the allophane films was investigated by optical microscopy (OM). The OM image of the translucent allophane films showed parallel straight lines crossing at right angles. These lines suggest the film was formed by some two-dimensionally ordered array of unit particles.

Motion estimation by decoupling rotation and translation in catadioptric vision

Previous works have shown that catadioptric systems are particularly suited for egomotion estimation thanks to their large field of view and thus numerous algorithms have already been proposed in the literature to estimate the motion. In this paper, we present a method for estimating six degrees of freedom camera motions from central catadioptric images in man-made environments. State-of-the-art methods can obtain very impressive results. However, our proposed system provides two strong advantages over the existing methods: first, it can implicitly handle the difficulty of planar/non-planar scenes, and second, it is computationally much less expensive. The only assumption deals with the presence of parallel straight lines which is reasonable in a man-made environment. More precisely, we estimate the motion by decoupling the rotation and the translation. The rotation is computed by an efficient algorithm based on the detection of dominant bundles of parallel catadioptric lines and the translation is calculated from a robust 2-point algorithm. We also show that the line-based approach allows to estimate the absolute attitude (roll and pitch angles) at each frame, without error accumulation. The efficiency of our approach has been validated by experiments in both indoor and outdoor environments and also by comparison with other existing methods.

WE‐D‐304A‐09: Characterization of Multi‐Beam Field Emission X‐Ray Source for Stationary Digital Breast Tomosynthesis

Purpose: The current prototype digital breast tomosynthesis (DBT) scanners are based on the regular full‐field digital mammography systems and require partial isocentric motion of a mammography x‐ray tube over certain angular range to record the projection views needed for reconstruction. This prolongs the scanning time and in turn degrades the imaging quality due to motion blur. We are developing a stationary DBT (s‐DBT) scanner to mitigate the above limitations. Method and Materials: The proposed s‐DBT system is based on the carbon nanotube multi‐pixel field emission x‐ray (MBFEX) technology demonstrated by our group. The pixilated and spatially distributed MBFEX source can generate x‐ray radiation from multiple views without any mechanical motion of the source, detector, or object. This enables the design of tomography systems with great flexibility in source configuration and imaging sequence. It further enables multiplexing imaging — simultaneously collection of multiple images using one detector. Results and Conclusions: To demonstrate the feasibility of the s‐DBT scanner, we have designed and constructed a proof‐of‐concept full‐field s‐DBT system. The configuration of the system, in terms of angular coverage, number of views, and dose, etc., closely resembles the Siemens DBT scanner for a more realistic comparison. In the Siemens DBT scanner, the x‐ray tube moves along an arc with the exposure points evenly distributed along the rotation route. Our s‐DBT scanner is designed with the MBFEX pixels positioned in a straight line parallel to the detector plane. We will report a detailed study on the design and the performance characteristics of the MBFEX source. In particular evaluation on key parameters including the x‐ray flux, the lifetime of the x‐ray source, effective x‐ray focal spot size, variation between different source, system spatial resolution, and x‐ray energy spectrum will be reported. These preliminary results demonstrate the feasibility of the proposed s‐DBT scanner.

A theoretical analysis of unsteady incompressible flows for time-dependent constitutive equations based on domain transformations

In this paper, we propose an analysis that allows calculation of kinematic histories in unsteady problems of continuum mechanics, in relation to the use of memory-integral constitutive equations. Such cases particularly concern flow conditions of processing rheology, requiring evaluation of strain or deformation rate tensors, for viscoelastic incompressible fluids as polymers. In two- and three-dimensional cases, we apply concepts of the stream-tube method (STM) initially given for stationary conditions, where unknown local or global mapping functions are defined instead of classic velocity–pressure formulations, leading to consider the flow parameters in domains where the streamlines and trajectories are parallel straight lines. The approach enables us to provide accurate formulae for evaluating the kinematics histories that can be used later for computing the stresses for a given memory-integral model.

The Problem of the Centre for Cubic Systems with Two Parallel Invariant Straight Lines and One Invariant Conic

For cubic differential systems with two parallel invariant straight lines and at least one invariant conic it is proved that a singular point with pure imaginary eigenvalues (a weak focus) is a centre if and only if the first three Liapunov quantities Lj , j = 1, 2, 3 vanish.

The bead model and limit behaviors of dimer models

In this paper, we study the bead model: beads are threaded on a set of wires on the plane represented by parallel straight lines. We add the constraint that between two consecutive beads on a wire; there must be exactly one bead on each neighboring wire. We construct a one-parameter family of Gibbs measures on the bead configurations that are uniform in a certain sense. When endowed with one of these measures, this model is shown to be a determinantal point process, whose marginal on each wire is the sine process (given by eigenvalues of large hermitian random matrices). We prove then that this process appears as a limit of any dimer model on a planar bipartite graph when some weights degenerate.

Quadratic Planar Systems with Two Parallel Invariant Straight Lines

In this paper, we classify the global phase portraits of all quadratic planar systems with two parallel invariant straight lines. The main techniques used are Poincare Compactification and Normal Forms Theory combined with the Neumann’s Theorem.

A SPECIAL ELECTRICAL TRANSPORT BEHAVIOR IN La0.67Sr0.33MnO3/CeO2 COMPOSITES

The composites with the nominal composition of (1-x) La 0.67 Sr 0.33 MnO 3 (LSMO)/x CeO 2 were fabricated by the sol–gel method. A special electrical transport behavior is observed in the ρ/ρTp versus temperature curves, where ρTp is the peak resistivity at the insulator–metal transition temperature (Tp). The curves for all samples with different CeO 2 content are parallel in the high-T insulator regime and in a certain temperature range below Tp. Furthermore, a series of parallel straight lines can be found in the [Formula: see text] versus temperature curves for the samples with different CeO 2 content. By considering the surface magnetization at the grain boundary, we obtain a simple expression for the temperature dependence of resistivity that can reproduce the experimental data in the high-T insulator regime and in a certain temperature range below Tp.

Full-azimuth imaging using circular geometry acquisition

Wide-azimuth (WAZ) towed-streamer acquisition has improv-ed the quality and reliability of subsalt imaging in the Gulf of Mexico, where WAZ surveys have typically been ac-quired using 3–4 seismic vessels, each shooting in straight parallel lines. However, acquisition of WAZ data using a single vessel and a circular geometry offers several potential ad-vantages, both for operational efficiency and geophysical analysis of subsurface rock properties. Modeling exercises indicate that circular acquisition geo-metry can deliver a better range of azimuths and offsets than parallel WAZ geometry. A feasibility test in the Gulf of Mexico shows that it is possible to sail along circles while main-taining constant streamer separation and achieving very accurate receiver positioning. Single-sensor recording enables effective attenuation of the additional coherent noise introduced by shooting in a curve. Prestack depth-migrated data from the circular geometry test compare favorably with a parallel geometry WAZ data set...