Miracle-dz/UniFAR-FTUs huggingface dataset:
Analysis of Pupil Replication

Pupil replication and hypertelescope systems for imaging telluric exoplanets in scattered light are treated. Analytic expressions for the spread functions in one and two dimensions and in the presence of various forms of error are given. Error effects considered include aperture misalignment, tilts, piston, pointing errors, and unequal beam amplitude. The performance of the two approaches is contrasted, and the analytic results are compared with simulation results.
O R-CONVERGENCE AND WEAK O R-CONVERGENCE OF NETS AND THEIR APPLICATIONS

In this paper, the theory of Oᵣ-convergence and weak Oᵣ-convergence of nets is introduced in L-topological spaces by means of neighborhoods and strong neighborhoods of fuzzy points based on Shi’s O-convergence.It can be used to characterize preclosed sets, preopen sets, δ-closed sets, δ-open sets, near compactness and near S∗-compactness.
New information on Dianmeisaurus gracilis Shang & Li, 2015

Dianmeisaurus gracilis is restudied on the basis of a new specimen. It provides some new information, especially that on the skull roof, to the species. The most striking of those new characters include the snout (preorbital region) shorter than the orbit, the interorbital septum extremely narrow, the frontal with a sharp process at both ends, and the posterior margin of the skull roof deeply V-shaped. A phylogenetic analysis with new information confirms that Dianmeisaurus is the sister group of Diandongosaurus and that these two genera, together with those Chinese taxa ( Majiashanosaurus , Dianopachysaurus , Keichousaurus , and Dawazisaurus ), form a monophyletic clade which is more closely related to the Nothosauroidea than to a clade formed by the European pachypleurosaurs.
Modeling, Synthesis and Characterization of a Millimeter-Wave Multilayer Microstrip Liquid Crystal Phase Shifter

Electromagnetic simulation software is used for modeling the properties of a 2–15 GHz liquid crystal microstrip phase shifter previously designed at Thomson-CSF. After experimental validation of the computed results, the software is applied to the modeling of a new 30–40 GHz multilayer microstrip phase shifter, where the active medium is a liquid crystal inserted between solid dielectric substrates. Measurements carried out at between 10 and 40 GHz on 4.35 cm long lines are in good agreement with theoretical predictions. A maximum experimental phase shift of 219.3° at 37 GHz (about 50°/ cm) was observed for a structure with a commercial liquid crystal (BDH-E44) and silica substrates.
Slow mode shocks in the Earth' magnetotail: ISEE-3

High time resolution magnetic field measurements adjacent to the boundary of the distant magnetotail plasma sheet have been analyzed. The nature of the changes in the field between the lobe and the plasma sheet is consistent with the boundary being a slow mode shock. The crossing times are relatively long (∼30 sec) implying a shock thickness estimated to be approximately 10³ km. An increase in the entropy of the electrons is consistent with dissipation at the shock. Reasonable shock normal directions are derived and may be used to determine the location of the spacecraft relative to the reconnection or merging region. It is suggested that a foreshock exists in which upstream wave and particle phenomena are occurring.
THE INFLUENCE OF EXTRANEOUS SOUNDS ON THE PERCEPTUAL ESTIMATION OF FIRST-FORMANT FREQUENCY IN VOWELS UNDER CONDITIONS OF ASYNCHRONY

The presence of an extraneous sound in the first formant (F1) region of a voiced vowel has been shown to influence its perceived phonetic quality when the vowel and the extraneous sound begin and end in synchrony. These experiments examine whether this effect, produced here by a pair of extraneous tones not harmonically related to the vowel’s fundamental frequency, depends on the degree of synchrony of the vowel and the tones. The phonetic effects of the tones were measured as a change in the position of the phoneme boundary on a continuum of vowels, perceived as changing from /ɪ/ to /ɛ/ as F1 was increased. Experiment 1 demonstrated that the boundary shift resulting from the addition of the tones declined when the tones began prior to the vowel. This effect might be due to adaptation or to perceptual grouping. In experiment 2, a sequence of “captor” tones was used in an attempt to reinstate the phonetic effects of these tones, by “grouping out” the portions that were not simultaneous with the vowel. This.
Energy dissipation and flow characteristics of baffles and sills on stepped spillways

In this study, a two-dimensional physical model was used to evaluate the effectiveness of adding baffles and sills at step edges or of shifting them from step edges of a 1V:1H sloping, short, sharp- or round-crested stepped spillway with an ogee inlet. A comparison between different configurations of baffles and sills was carried out with respect to the energy dissipation and the flow characteristics. The baffle-shifted round-crested spillway gives the smallest discharge required for the onset of a skimming flow among all other configurations. The baffle-edged chute dissipates more energy than the sill-edged spillway. Shifting baffles or sills from the sharp edges decreases the energy dissipation. Shifting baffles or sills from the round-crested spillway increases the energy dissipation in the range of the discharges studied. Empirical equations for energy dissipation are introduced for practical application of spillways of comparable similar conditions.
Algebraic Discrete Nonlocal (DNL) Absorbing Boundary Condition for the Ship Wave Resistance Problem

An absorbing boundary condition for the ship wave resistance problem is presented. In contrast to the Dawson-like methods, it avoids the use of numerical viscosities in the discretization, so that a centered scheme can be used for the free surface operator. The absorbing boundary condition is “completely absorbing,” in the sense that the solution is independent of the position of the downstream boundary and is derived from straightforward analysis of the resulting constant-coefficients difference equations, assuming that the mesh is 1D-structured (in the longitudinal direction) and requires the eigen-decomposition of a matrix one dimension lower than the system matrix. The use of a centered scheme for the free surface operator allows a full finite element discretization. The drag is computed by a momentum flux balance. This method is more accurate and guarantees positive resistances.
Experimental investigation on cellular breakup of a planar liquid sheet from an air-blast nozzle

The cellular breakup phenomenon is investigated experimentally for a planar liquid sheet from an air-blast nozzle. The dominant sinuous wave growing spatially downstream forms complicated cellular structures of perforated thin films and surrounding ligaments. Several characteristic parameters are measured from photographic images and compared with linear temporal analysis. The dominant wavelength is proportional to the inverse square of the relative velocity between air and liquid. The estimated breakup time matches the growth time of the most unstable wave, while the breakup length corresponds to a product of breakup time and liquid velocity. Numerical simulation shows a substantially reduced mean effective velocity near flow reattachment region of the air stream. Air turbulence seems to play a major role on initial perturbations of cellular breakup in the given nozzle configuration. The measured spatial growth rates are always less than linear predictions due to deviation from the linear regime at higher amplitudes.
Extremely low threshold-current-density InGaAs quantum-well lasers with emission wavelength of 1215-1233 nm

Extremely low threshold-current-density In0.4Ga0. 6As quantum-well (QW) lasers have been realized in the 1215–1233 nm wavelength regime. The measured room-temperature threshold current density of the InGaAs QW lasers with a cavity length of 1000 μm is only 90 A/cm2 at an emission wavelength of 1233 nm.
Nonlinear rheology of colloidal gels with intermediate volume fraction

The depletion attraction, induced upon addition of a nonadsorbing polymer to a colloidal solution, can lead to gel formation at sufficiently high polymer concentrations, which corresponds to strong attractive interactions. We have investigated the nonlinear rheological response, in particular the yielding, of colloidal gels with an intermediate volume fraction and variable interparticle attraction. Two distinct yielding processes are observed in both oscillatory experiments, namely, dynamic strain sweeps and transient experiments, here step rate, creep, and recovery tests. The first yielding process occurs at strains similar to the range of the interparticle potential and is interpreted as the breaking of bonds, which destroys the particle network and leads to individual clusters. The process of bond breaking is successfully modeled as the escape of a particle from the potential well of its nearest neighbor. The second yield point occurs at larger strains and is related to the deformation and fragmentatio.
Sensitivity of shallow water transmission loss to source and receiver proximity to a hard bottom under downward refracting conditions

Under downward refracting conditions, raypaths from a shallow source will tend to have grazing angles at a hard bottom that are greater than the critical angle and therefore suffer a relatively large loss per bounce. As the source depth increases, lower grazing angles can be obtained. When the grazing angle becomes less than the critical angle, bottom loss per bounce is significantly reduced allowing a possible reduction in propagation loss. An analysis is made for a North Atlantic shallow water area south of Long Island under summer conditions to determine the sensitivity of transmission loss to changes in source and receiver depth for ranges up to 50 km. The results are compared to the previous results of Cole and Podeszwa [B. F. Cole and E. M. Podeszwa, J. Acoust. Soc. Am. 41, 1479–1484 (1967)].
Kinetic theory of a binary mixture of nearly elastic disks with size and mass disparity

Corrections are provided for two transport coefficients derived by Willits and Arnarson [Phys. Fluids 11, 3116 (1999)] for a binary mixture of nearly elastic, circular disks using the revised Enskog theory. The corrected viscosity coefficient is compared to the shear viscosity obtained from simulation results of a bidisperse mixture of inelastic, hard disks, undergoing uniform shear flow. The agreement is good for a wide range of sizes and masses.
Boost matrix elements and Clebsch–Gordan coefficients of the homogeneous Lorentz group

It is shown that the boost matrix elements of SO(3,1) obtained by Smorodinskii and Shepelev can be written as a sum of two Fourier series, whose coefficients are Clebsch–Gordan coefficients of SO(3) with complex angular momenta and magnetic quantum numbers. Moreover, the second term is equal to zero for all representations of the principal series except the most degenerate case. The connection between our expression and the spherical functions of Dolginov and other authors is explained. It is also noted that there are two ways of writing the boost matrix elements of SO(3,1), differing from each other by a phase factor. A proof for the orthogonality relation of the representation functions of SO(3,1) is given in the Appendix. The Clebsch–Gordan coefficients of SO(3,1) for the principal series in the general case (σ1ν1) × (σ2ν2) → (σ3ν3) are obtained as X functions with complex angular momenta. An integral representation for these X functions is obtained. It is shown that the CG coefficients of SO(3,1) have.
Drag Reduction Effect of Rod-Like Polymer Solutions. I. Influences of Polymer Concentration and Rigidity of Skeltal Back Bone

Drag reduction behaviors of xanthan polysacharide and scizophyllum polysacharide solutions are presented. The friction factor relation of \(1/\sqrt{f}=4.0\cdot\log (Re\cdot\sqrt{f})-0.4+\delta\) is observed for solutions of polymers having long persistent lengths, where f · R e and δ are a Fanning friction factor, a Reynolds number and a constant, respectively. On the other hand, the relation of \(1/\sqrt{f}=(4.0+\text{D})\cdot\log (Re\cdot\sqrt{f}+\text{A}\) is observed for solutions of polymers having short persistent lengths, where D and A are constants. From concentration dependencies of these relations, the following relations are found; S + ∝ C p 0.75 for the former case and S + ∝ C p 0.75 ·ln (γ v /γ v * ) for the latter case, where S + , C p , γ v and γ v * are a normalized slipping velocity between a viscous sublayer and a Newtonian plug zone, a polymer concentration, a shear rate in the viscous sublayer and an onset γ v for the drag reduction, respectively. The γ v * is found to be a monotonical.
Wavelet Analysis and Envelope Detection For Rolling Element Bearing Fault Diagnosis—Their Effectiveness and Flexibilities

The components which often fail in a rolling element bearing are the outer-race, the inner-race, the rollers, and the cage. Such failures generate a series of impact vibrations in short time intervals, which occur at Bearing Characteristic Frequencies (BCF). Since BCF contain very little energy, and are usually overwhelmed by noise and higher levels of macro-structural vibrations, they are difficult to find in their frequency spectra when using the common technique of Fast Fourier Transforms (FFT). Therefore, Envelope Detection (ED) is always used with FFT to identify faults occurring at the BCF. However, the computation of ED is complicated, and requires expensive equipment and experienced operators to process. This, coupled with the incapacity of FFT to detect nonstationary signals, makes wavelet analysis a popular alternative for machine fault diagnosis. Wavelet analysis provides multi-resolution in time-frequency distribution for easier detection of abnormal vibration signals. From the results of extensive experiments performed in a series of motor-pump driven systems, the methods of wavelet analysis and FFT with ED are proven to be efficient in detecting some types of bearing faults. Since wavelet analysis can detect both periodic and nonperiodic signals, it allows the machine operator to more easily detect the remaining types of bearing faults which are impossible by the method of FFT with ED. Hence, wavelet analysis is a better fault diagnostic tool for the practice in maintenance.
Two-echelon multi-item spare parts systems with emergency supply flexibility and waiting time constraints

We consider a two-echelon multi-item spare parts inventory system in which supply flexibility through both lateral transshipments and direct deliveries are used in response to stock-outs. We develop a simple heuristic to determine the stocking levels for each type of spare part at the central warehouse and local warehouses minimizing the expected total system cost subject to a target level for the average waiting time across items at each local warehouse. Numerical comparisons between the heuristic's objective function values and lower bounds obtained by applying Lagrangian relaxation techniques show that the heuristic performs well. A study to evaluate the relative merits of a two-echelon system as opposed to a single-echelon system is also presented. We find that the presence of lateral transhipment improves the performance of the single-echelon system considerably. A two-echelon system is only worth implementing when lateral transhipments are not possible.
Repeatability of redundant manipulators: mathematical solution of the problem

Consider a redundant manipulator whose hand is to trace a path in its workspace. A local control strategy that governs the manipulator is a law that assigns an infinitesimal change in the joint angles so that the hand will move infinitesimally in the direction designated by the path. Because of the redundancy, there can be many such control strategies. For some strategies it turns out that when the hand returns to its initial position, the joint angles do not always return to their initial values. To determine a priori whether a given local control strategy guarantees repeatability or not, it is necessary to deduce its global properties as well as its local properties. This is achieved by considering integral surfaces for a distribution in the joint space. This yields a necessary and sufficient condition, in terms of Lie brackets, for a control to be repeatable. >
Hydrodynamic Aspects Of Moored Semisubmersibles And Tlp's

The mean and low-frequency horizontal wave drift forces on 2 types of semi-submersible structures in regular and in irregular waves are determined from model tests and calculations. For the measurement of the low-frequency drift forces in irregular waves use is made of a special dynamic system of restraint. Comparison of measured and computed drift forces in irregular waves show increasing divergence between predictions based on 3-dimensional potential theory and results of experiments with increasing severity of the irregular sea conditions. Comparison between computed and measured mean drift forces in regular waves show increasing divergence at lower wave frequencies. A simple model for approximating viscous contributions to the drift forces in irregular waves is applied to some test results and it is shown that the correlation between measurements and predictions is improved. In order to gain more detailed insight in the mechanisms of the viscous contribution to the drift force tests were carried out with single fixed vertical cylinder in regular waves. The results of tests confirm that in conditions of waves without current the major part of the viscous contribution to the drift force is confined to the splash zone of the cylinder.
Uniqueness of complex contact structures

Let X be a complex Fano-manifolds with second Betti-number 1 which carries a contact structure. It follows from previous work that such a manifold can always be covered by lines. Thus, it seems natural to consider the geometry of lines in greater detail. In this brief note we show that if x in X is a general point, then all lines through x are smooth. If X is not the projective space, then the tangent spaces to lines generate the contact distribution at x. As a consequence we obtain that the contact structure on X is unique, a result previously obtained by C. LeBrun in the case that X is a twistor space.
Numerical Modeling of the Absorption and Scattering of Acoustic Radiation by Sunspots

We present numerical calculations of the scattering of acoustic-gravity waves by a model sunspot consisting of an inhomogeneous, vertically magnetized region embedded in a polytropically stratified layer. The calculations show the transformation of incoming f-mode and p-mode power into downward-propagating, slow magnetoacoustic waves resulting in substantial absorption of incident f-modes and first-order p-modes and indicating that the slow-mode transformation model is a viable explanation for the observed absorption. In addition to absorption, we find large scattering phase shifts for the f-modes. Phase shifts are small for all p-modes. Coupling between modes of different radial order is generally small. The remaining differences between our results and the observations may constitute evidence that, if the mode transformation picture is correct, real sunspots must deviate significantly from the simple unidirectional field geometry we use here. In particular, we suggest that a sunspot consisting of a bundle of fibrils, in each of which the magnetic flux density increases rapidly with depth, would reproduce more closely the measured strong absorption and scattering of p-modes.
The Stromlo-APM redshift survey. I: The luminosity function and space density of galaxies

The first results from a new redshift survey of southern galaxies are presented. The survey is essentially complete to a magnitude limit of b J = 17.15 and consists of 1769 galaxies sampled randomly at a rate of 1 in 20 from the APM galaxy catalogs. Our survey samples a volume ∼30 times larger than the 14.5 mag CfA Redshift Survey and so can provide an accurate determination of the luminosity function and mean space density of galaxies
On the $K$-Theory of $C^*$-Algebras of Principal Groupoids

We consider the K -theory of C ∗ -algebras of principal r -discrete groupoids. We describe two basic situations in which three groupoids are related; they can very loosely be described as “factor groupoids” and “sub- groupoids. ” For each, we show that there is a six-term exact sequence of associated K -groups. We present examples which arise from dynamical systems and from problems in the study of the orbit structure of topological systems. We also obtain the usual Mayer-Vietoris sequence in topological K -theory as a corollary.
Was Loitsyansky correct? A review of the arguments

Loitsyansky's integral, I, is important because it controls the rate of decay of kinetic energy in freely-evolving, isotropic turbulence. Traditionally it was assumed that I is conserved in decaying turbulence and this leads to Kolmogorov's decay law, u 2 ∼ t −10/7. However, the modern consensus is that I is not conserved, which is a little surprising since Kolmogorov's law is reasonably in line with the experimental data. This discrepancy led Davidson (2000 J. Fluid Mech. submitted) to reassess the entire problem. He concluded that, for certain initial conditions, which are probably typical of wind tunnel turbulence, freely evolving turbulence reaches an asymptotic state in which the variation of I is negligible, a conclusion which is at odds with the predictions of certain closure models. In this review we revisit this debate. We explain why the widespread belief in the time dependence of I owes much to a misinterpretation of Batchelor and Proudman's original analysis (1956 Phil. Trans. R. Soc. A 248 36.
Upper-Ocean Thermal Structure and the Western North Pacific Category 5 Typhoons. Part II: Dependence on Translation Speed

Abstract Using new in situ ocean subsurface observations from the Argo floats, best-track typhoon data from the U.S. Joint Typhoon Warning Center, an ocean mixed layer model, and other supporting datasets, this work systematically explores the interrelationships between translation speed, the ocean’s subsurface condition [characterized by the depth of the 26°C isotherm (D26) and upper-ocean heat content (UOHC)], a cyclone’s self-induced ocean cooling negative feedback, and air–sea enthalpy fluxes for the intensification of the western North Pacific category 5 typhoons. Based on a 10-yr analysis, it is found that for intensification to category 5, in addition to the warm sea surface temperature generally around 29°C, the required subsurface D26 and UOHC depend greatly on a cyclone’s translation speed. It is observed that even over a relatively shallow subsurface warm layer of D26 ∼ 60–70 m and UOHC ∼ 65–70 kJ cm−2, it is still possible to have a sufficient enthalpy flux to intensify the storm to category 5.
An Instability of Mature Cold Fronts

Abstract An instability of a cold front possessing a low-level warm-band precursor is examined within an f-plane, quasi- and semigeostrophic framework. The basic frontal state is taken to be two-dimensional and of uniform potential vorticity. Theoretical considerations pinpoint the source and nature of the instability to be a vortex interaction effect acting across the thermal maximum of the warm band. They also reveal that the most unstable mode associated with this flow configuration has a mixed barotropic-baroclinic character and possesses some features (e.g., a wavelength ∼1000 km and a doubling time ∼1½ days) that are akin to surface frontal waves. In addition nonlinear numerical model simulations demonstrate that the frontal wave growth equilibrates rapidly but not before the establishment of a rich mesoscale flow structure. A brief assessment is presented of the relationship of this diagnosed instability to realized atmospheric flow patterns and to other mechanisms that have been postulated for the.