Miracle-dz/UniFAR-FTUs huggingface dataset:
A Performance Study of MHD-Bypass Scram jet Inlets with Chemical Nonequilibrium

The effect of thermo-chemical non-equilibrium on a weakly ionized gas in the presence of a magnetic field is studied in this paper. The numerical simulations are performed using the compressible viscous electroMHD equations. Two-dimensional electroMHD equations in generalized coordinates, along with a chemical kinetics model and a variable electrical conductivity model, are solved using a modified four-stage Runge-Kutta time integration scheme with second-order accurate spatial discretization. A symmetric Davis-Yee Total Variation Diminishing (TVD) flux limiter is employed to damp the oscillations in the shock regions. Numerical simulations are performed for hypersonic flow in a scramjet inlet. Numerical results show the combined effect of the thermochemical non-equilibrium and the magnetic field on the air plasma. Computations are compared with a simple one-dimensional theoretical analysis because of the lack of other computations and experimental data. NOMENCLATURE Q field vector E flux vector component in the jc-direction F flux vector component in the y-direction x Cartesian coordinate y Cartesian coordinate p density * Bloomfield Distinguished Professor and Executive Director, Fellow AIAA 4 Research Scientist, Associate Member AIAA © by the authors p, species density u velocity component in the jc-direction v velocity component in the ^-direction \v velocity component in the z-direction V velocity vector Bx magnetic field component in the x-direction By magnetic field component in the ^-direction Bz magnetic field component in the z-direction p static pressure pc electronic pressure evi vibrational energy of species / eei Electronic excitation energy of species / e, total energy per unit mass Cw specific heat at constant volume of species / cv speed of sound hoj heat of formation of species / vax Alfven wave velocity in the x-direction vay Alfven wave velocity in the ^-direction X eigenvalue £, generalized coordinate r) generalized coordinate J Jacobian of transformation v^ fast wave velocity in the £ -direction v/n fast wave velocity in the r| -direction v^ slow wave velocity in the E, -direction vvn slow wave velocity in the T| -direction L^ inverse right eigenvector associated with Jacobian matrix A R^ right eigenvector associated with Jacobian matrix A D. diagonal eigenvalue matrix associated with Jacobian matrix A American Institute of Aeronautics and Astronautics (c)2001 American Institute of Aeronautics & Astronautics or Published with Permission of Author(s) and/or Author(s)' Sponsoring Organization.
Rays, Beams, and Modes Pertaining to the Excitation of Dielectric Waveguides

The two-dimensional problem of excitation of an inhomogeneous dielectric layer by a Gaussian beam is considered, with emphasis on useful representations that treat the field either in terms of multiple reflections or in terms of guided modes. A recently developed method is employed whereby the beam fields are generated from line source fields by assigning a complex value to the source coordinates. When applied to the asymptotic solution for the line source field, this procedure furnishes a simple and quantitative relation between line-source-excited ray optics and paraxial beam optics. It also clarifies the role of lateral ray and beam shifts for reflection at a boundary with incidence-angle-dependent reflection coefficient, especially when multiply reflected fields are converted into modal form. Results are given for beams which are reflected at both boundaries, reflected at one boundary and refracted before reaching the other boundary, and trapped by refraction without reaching either boundary. In the first case, conversion to modal form is more convenient at large distances whereas in the latter case, paraxial beam tracking is preferable.
On a Method of Investigating Periodicities in Disturbed Series, with Special Reference to Wolfer's Sunspot Numbers

If we take a curve representing a simple harmonic function of the time, and superpose on the ordinates small random errors, the only effect is to make the graph somewhat irregular, leaving the suggestion of periodicity still quite clear to the eye. Fig. 1 ( a ) shows such a curve, the random errors having been determined by the throws of dice. If the errors are increased in magnitude, as in fig. 1 ( b ), the graph becomes more irregular, the suggestion of periodicity more obscure, and we have only sufficiently to increase the “errors” to mask completely any appearance of periodicity. But, however large the errors, periodogram analysis is applicable to such a curve, and, given a sufficient number of periods, should yield a close approximation to the period and amplitude of the underlying harmonic function. When periodogram analysis is applied to data respecting any physical phenomenon in the expectation of eliciting one or more true periodicities, there is usually, as it seems to me, a tendency to start from the initial hypothesis that the periodicity or periodicities are masked solely by such more or less random superposed fluctuations — fluctuations which do not in any way disturb the steady course of the underlying periodic function or functions. It is true that the periodogram itself will indicate the truth or otherwise of the hypothesis made, but there seems no reason for assuming it to be the hypothesis most likely a priori .
A Path integral for spin

A path integral for spinning particles is developed. It is a one-particle theory, equivalent to the usual quantum mechanics. Our method employs a classical model for spin which is quantized by path integration. The model, the spherical top, is a natural one from a group-theoretic point of view and has been used before in a similar context. The curvature and multiple connectedness of the top coordinate space [$\mathrm{SO}(3)$] provide some interesting features in the sum over paths. The Green's function which results from this procedure propagates all spins, and recovery of the usual Pauli spinors from this formalism is achieved by projection to a specific spin subspace.
Overwrite as a function of record gap length

In disk recorders, a common head is used for both recording and reproducing. Old data are not erased but are simply recorded over. The partially erased old data signal appears in the new data as error-producing interference. The amount of erasure of the old data signal is called "overwrite", and 30 dB is typically required. To avoid the reproduce gap null, the head gap is usually chosen to be less than half of the 2F (or bandedge) flux change length. To achieve adequate overwrite using a gap this small, it is necessary to use a very thin recording layer. A simple explanation for this, involving greater depth of penetration for low density signals, is at best incomplete. The data below show that the overwrite phenomenon is complex. Overwrite spectra measured using a thick medium show large resonance peaks whose amplitude and position depend on the record gap, record current, and the densities of the overwriting signal and the signal being overwritten.
On the variability of sporadic E

The analysis of digital ionograms taken in short-time intervals shows rapid changes of sporadic E parameters. This is directly visible in the variation of the top frequency or maximum electron density of such layers. Angle of arrival data which were available with those ionograms also showed fast changes of the apparent direction and often large deviations from vertical propagation. 5 refs.
The Folded Normal Distribution: Accuracy of Estimation By Maximum Likelihood

This paper is a sequel to two previous papers on the subject of the Folded Normal Distribution appearing in Technometrics, S, pp. 543–550 and 551–562, (1961). In these earlier papers methods for estimating the parameters of the Folded Normal Distribution were proposed. Thii paper gives approximations for the standard errors for the maximum liklihood estimates of these parameters.
Integration and test of the first light AO system for LBT

The paper describes the single conjugate AO system called WLBT to be mounted at LBT in late summer 2004. The WLBT is part of the Acquisition, Guiding & Wavefront sensing unit (AGW) attached to the front bent Gregorian foci derotator. The two key features of this system are the use of a pyramid wavefront sensor with variable sampling between 30x30 and 5x5 sub apertures plus the use of an adaptive secondary mirror having 672 actuators as wavefront corrector. The AO system is mainly working as atmospheric disturbance correction system in the near infrared (J,H and K band). However due to the large number of actuators and sub apertures, it can obtain good performance even in R and I band. The paper reports about development and integration of the system final unit in the lab. Then some initial tests aimed to do a system characterization are reported. The results we obtained are used to give an estimation of the performance that the system can reach at the telescope in terms of limiting magnitude.
On time scaling for nonlinear systems: Application to linearization

In this note, we propose a method to analyze systems in a time scale which is varied depending on the state such as dt/d\tau = s(x) (where t and τ are the actual time scale and that of new one, respectively, and s(x) is the function which we call time scaling function). Analysis of the system in the new time scale τ enables us to investigate the intrinsic structure of the system. A linearization problem in the new time scale is formulated as wide-sense feedback equivalence and is solved. It is also shown that the time scaling function which makes the system linear is derived as the solution of differential equations.
Experimental Values of Kolmogorov Constant of Turbulence

Experimental values of the Kolmogorov constant Ko, translated from the experimentally measured one-dimensional (1-D) energy spectra of high-Reynolds-number turbulence, depend upon which form of the turbulence energy spectrum is used over the small scale range captured in the experiments. Most published experimental values of Ko ranges from 1.3 to 2.1, and are based upon a simple form of the energy spectrum which neglects the bump phenomenon. When improved forms of the energy spectrum, which take into account the bump phenomenon, are used, it is found that the experimental values of the Kolmogorov constant are between 0.9 and 1.5, much lower than most published experimental values.
Further Properties of Reliability Importance for Continuum Structure Functions

A continuum structure function (CSF) is a nondecreasing mapping from the unit hypercube to the unit interval. The Kim-Baxter definition of the reliability importance of component i in a CSF at system level α, Ri(α), say, is reviewed. Conditions under which Ri(α) is positive, under which Ri(α) is a continuous function of α, and under which Ri(α) ≥ Rj(α) uniformly in α are presented. A simple algorithm for evaluating Ri(α) is described.
Slow protons as a signature of zero-photon dissociation of H2+ in intense laser fields

We have observed protons with near-zero kinetic energy that originate from the interaction of a frequency tripled (λ = 266 nm), 250 fs intense Ti:sapphire laser with H2 molecules. These protons are tentatively ascribed to zero-photon dissociation (ZPD) of H2+. Earlier quantum mechanical calculations show that such a process should occur due to the partial escape of the vibrational wavepacket that is trapped in the laser-induced, adiabatic well above the one-photon crossing of dressed Floquet states. The fact that slow protons are also observed at the second harmonic (λ = 400 nm), but to a lesser extent, is consistent with the ZPD explanation.
Elastic scattering of intermediate- and high-energy electrons by N2 and CO in the two-potential coherent approach

Elastic differential, integral and momentum transfer cross sections are reported for the scattering of electrons by N2 and CO in the energy range 40-800 eV. The two-potential approach of Hayashin and Kuchitsu (1976) is employed, in which the total interaction potential is represented as a sum of the short- and the long-range potentials. It is found that the interference cross section term arising due to the coherent sum of the scattering amplitudes from the short- and the long-range parts of the interaction potential, is stronger than the pure long-range potential cross section term, of course, in the small angular region (<or=40 degrees ). The author also studies the multiple scattering within the molecule and finds that in the multiple scattering series the single-double (SD) term dominates over the pure double-double (DD) term in the whole energy region considered. However, there is evidence (below 100 eV) that the DD term is compatible with the SD term in the middle angles and exhibits some peaking behaviour at about 90 degrees . To evaluate elastic scattering amplitudes for each potential, a partial-wave analysis was performed. Results are discussed and compared with the recent absolute measurements. All the author's results are in very good accord with the observed data.
X‐ray Sources in Two Nearby Dwarf Spheroidal Galaxies

We observed the dwarf spheroidal (dSph) galaxy Leo I for 80,000 seconds with XMM‐Newton and detected 105 non Galactic X‐ray sources (XRS) in its field. We examined deep optical images and catalogs, and discuss the possibility that some of the sources are Low Mass X‐Ray Binaries (LMXB) intrinsic to Leo I. We also studied an archival XMM‐Newton observation of the Fornax dwarf spheroidal galaxy, and compare it with Leo I. 104 non Galactic XRS were detected in the Fornax field; one of them coincides with a blue object at the outskirt of the Fornax 4 globular cluster. In both observations about a third of the XRS are identified with extragalactic objects observed in optical and radio. We discuss the similarities between the two XRS groups and the differences, which may be due to the a small number of intrinsic LMXB in the two galaxies. Fornax is at half the distance of Leo I, and has an almost 4 times larger luminous mass, but is also much more sparse on the sky. Leo I has had at least one more recent episode .
WEIGHTING OF DATA

When data are used without weights, each record counts the same as any other record. Implicit in such use are the assumptions that each record has an equal probability of being selected and that noncoverage and nonresponse are equal among all segments of the population. When deviations from these assumptions are large enough to affect the results obtained from a data set, then weighting each record appropriately can help to adjust for assumption violations. An additional (but conceptually unrelated) reason for weighting is to make the total number of cases equal to some desired number which, for state BRFSS data, is the number of people in the state who are aged 18 years and older. In the BRFSS, such raking serves as a blanket adjustment for noncoverage and nonresponse and forces the total number of cases to equal population estimates for each geographic region, which for the BRFSS is usually a state.
Parameter Estimates for Symmetric Stable Distributions

Abstract Building on results of an earlier article [6], estimators are suggested for the scale parameter and characteristic exponent of symmetric stable distributions, and Monte Carlo studies of these estimators are reported. The powers of various goodness-of-fit tests of a Gaussian null hypothesis against non-Gaussian stable alternatives are also investigated. Finally, a test of the stability property of symmetric stable variables is suggested and demonstrated.
Structural Synthesis of Serial Robotic Manipulators Subject to Specific Motion Constraints

An intuitive approach for the structural synthesis of serial robotic manipulator subject to specific motion constraints is presented in this paper. According to the required f-DOF αRβT motion of the end-effector, for f = 2, 3, [[ellipsis]] or 6 and α, β = 0, 1, 2 or 3, all feasible serial-type robot structures can be systematically generated via the proposed method. The approach begins at the enumeration of joint connectivity, proceeds with the assignment of joint types, and continues by the consideration of motion constraints for the robot. A couple of examples, including the synthesis of the 3-, 4- and 5-DOF serial manipulators, are furnished for illustration. It shows that this method is especially exploitable when the end-effector is required to be immovable in certain orientations or directions with respect to either local coordinate system or global coordinate system. The result is particularly beneficial for practical industrial applications.Copyright © 2010 by ASME
Time-averaged hydrodynamic roughness of a noncolloidal sphere in low Reynolds number motion down an inclined plane

A system consisting of a spherical particle in motion down an inclined planar surface in a viscous liquid was investigated theoretically and experimentally to examine the effects of surface roughness on the interactions between the sphere and the plane. Two characteristic roughness scales were used to describe the microscopic surface roughness of the sphere. The smallest roughness elements are assumed to dominate the surface, and the largest roughness elements are more sparse. The time-averaged nominal separation between the sphere and the plane was found to increase as the planar surface was made steeper. This apparent hydrodynamic roughness is governed by the heights of the smallest roughness when the sphere resides on a horizontal plane, whereas the largest roughness elements govern the apparent hydrodynamic roughness when the plane is inclined at a steep angle. On a steep incline, the normal component of the gravitational force that drives the sphere toward the plane is relatively weak. Hence, as the sphere migrates toward the plane after contact with a large asperity ends, its rotation may result in another large asperity forcing the sphere away from the plane before contact with the smaller asperities occurs. The time-averaged separation at intermediate angles increases with increasing surface coverage by the largest roughness elements. The method of Smart and Leighton [Phys. Fluids A 1, 526 (1989)] was modified to determine the hydrodynamic separation between the sphere and the plane during its motion down the incline. The apparent hydrodynamic roughness values obtained in the experiments increase as the angle of inclination of the plane was increased, and provide a satisfactory validation of the model. The relatively large but sparse roughness elements have a disproportionate effect on the time-averaged hydrodynamic roughness, especially at high angles of inclination. These findings may be important in the interaction of pairs of spherical particles in viscous suspensions, where the effective angle of inclination varies significantly. For example, the presence of a low concentration of relatively large roughness elements should result in significantly higher levels of hydrodynamic diffusion.
Comments on Software Process Improvement Methodologies Using QFD

With rapid technological innovation and changes, the key to the survival company is the continuous improvement of its process. In this paper, we evaluate software process improvement (SPI) methodologies using QFD. There are Richardson's approach, Zultner's approach and SAP'S QFD for SPI. Then, we put on proposed model: CMMI staged model using QFD.
A note on models using the branching process with immigration stopped at zero

The Galton-Watson process with immigration which is time-homogeneous but not permitted when the process is in state 0 (so that this state is absorbing) is briefly studied in the subcritical and supercritical cases. Results analogous to those for the ordinary Galton-Watson process are found to hold. Partly-new techniques are required, although known end-results on the standard process with and without immigration are used also. In the subcritical case a new parameter is found to be relevant, replacing to some extent the criticality parameter.
Size Effect in Blunt Fracture: Concrete, Rock, Metal

The fracture front in concrete, as well as rock, is blunted by a zone of microcracking, and in ductile metals by a zone of yielding. This blunting causes deviations from the structural size effect known from linear elastic fracture mechanics (LEFM). The size effect is studied first for concrete or rock structures, using dimensional analysis and illustrative examples. Fracture is considered to be caused by propagation of a crack band that has a fixed width at its front relative to the aggregate size. The analysis rests on the hypothesis that the energy release caused by fracture depends on both the length and the area of the crack band. The size effect is shown to consist in a smooth transition from the strength criterion for small sizes to LEFM for large sizes, and the nominal stress σN at failure is found to decline as (1+λ/λ0)-1/2 in which λ0=constant and λ=relative structure size. This function is verified by Walsh's test data. If reinforcement is present at the fracture front and behaves elastically, .
The early Mesozoic saurischian trackways Evazoum and Otozoum: implications for ‘prosauropod’ (basal sauropodomorph) gaits

ABSTRACT Trackways of bipeds and quadrupeds attributed to Late Triassic and Early Jurassic basal sauropodomorphs (‘prosauropods’) fall into several ichnogenera. Four of these – Otozoum, Pseudotetrasauropus, Evazoum and Kalosauropus – are conceptually subsumed into the OPEK plexus, where the former two represent large facultative quadrupeds, and the latter two represent bipeds. In revaluating ~53 measurable Evazoum tracks from 13 Upper Triassic sites in the Northern Hemisphere, we found a consistently enlarged proximal pad on digit II, which together with digit I show highly variable registration. These suggest that the trackmakers tended to preferentially carry weight on digits III and IV. Furthermore, over a dozen Evazoum trackways also indicate notable variations in trackway width, consistent with previous inferences about the ‘prosauropodian’ gait. Comparisons to five Kalosauropus trackways from the Lower Jurassic of the Southern Hemisphere show that these two more closely related track types were likely made by basal sauropodomorphs (prosauropods) that were more fully adapted to obligatory bipedalism. The much larger Otozoum, reported from 16 trackways globally from both the Upper Triassic and Lower Jurassic, has trackway patterns that indicate changes in trackway width and shifts between bipedal and quadrupedal progression.
Come-On: An Adaptive Optics Prototype Dedicated To Infrared Astronomy

The paper presents the status of the COME-ON (CGE Observatoire de Meudon ESO ONERA) experiment. This instrument, developed and tested by several European laboratories, is an adaptive optical system with a 19 actuators deformable mirror and a Hartmann Shack type wavefront sensor. The wavefront sensing is performed at visible wavelengths; a special computer drives the deformable mirror which should achieve diffraction limited infrared imagery with large optical telescope. The different components and their individual characteristics are described. The results of the tests of some components are given: 19 actuators deformable mirror, tip-tilt mirror. The expected performances are summarized and possible applications of the instrument to astronomical sources are presented. The isoplanaticity aspect, the required temporal bandwidth and reference source brightness is discussed. The conclusions of the experiment will be used for the design of adaptive optics for the ESO Very Large Telescope.