Miracle-dz/UniFAR-FTUs huggingface dataset:
Reduced basis alternatives to the solution of nonlinear dynamical systems

The research deals with predicting the geometric nonlinear dynamic response of a structure under impulsive loading by means of reduction methods. Techniques for reducing the number of equations to be solved, e.g., where such equations come from a finite element model, are referred to as reduction methods. The order of a dynamical system is reduced by a Rayleigh-Ritz technique using selective basis vectors. These vectors are Rayleigh-Ritz approximation functions which are not the exact eigenvectors of the system. Ritz vectors can be generated with less computational effort than needed to generate eigenvectors. Furthermore, the basis set is augmented by derivatives of Ritz vectors and updated Ritz vectors. These types of vectors are added to account for the nonlinearities of the dynamical system. The proposed reduction technique is enhanced by updating the stiffness matrix with a reasonable reassembly frequency. An error norm, which is a weighted Euclidean norm of the unbalanced force vector, is utilized to determine when updating basis vectors is necessary. Nomenclature C = damping matrix for the structure C = reduced damping matrix for the structure e = error norm defined by Eq. (44) /, = total unbalanced force vector at time t K = stiffness matrix for the structure K = reduced stiffness matrix for the structure K(d"> = stiffness matrix with small change in 5th term of Z K* = effective stiffness matrix K* = reduced effective stiffness matrix M = mass matrix for the structure M = reduced mass matrix for the structure m = number of basis vectors Nf = frequency of updating stiffness Nu = number of basis vectors updating n = total number of DOF in the finite element model P = applied loads vector P* = effective loads vector P* = reduced effective loads vector td = time duration of impulsive load A? = time integration step U = displacement vector U = velocity vector U = acceleration vector U = reduced displacement vector with small change in 5th term zs = 5th components of reduced displacement vector I, = rth natural period of structure ^ = matrix of basis vectors fa = ith basis vector
Determination of Optical Constants from Reflectance or Transmittance Measurements on Bulk Crystals or Thin Films

The optical constants of bulk materials and thin films have been conveniently determined employing an automatic curve-fitting procedure to obtain a classical oscillator fit to reflectance and/or transmittance data. The method compares favorably in convenience and accuracy with a Kramers–Kronig analysis of bulk reflectivity spectra and is a better technique than the R,T or T,T methods presently used to analyze spectro-photometric data of thin films.
Lead‐210 and polonium‐210 in the atmosphere

The concentration of Pb-210 has been measured at several altitudes in the atmosphere over the United Kingdom during 1958. The gradient into the lower stratosphere was less steep than observed by Burton & Stewart (1960) and conformed to the diffusion models of Jacobi & Andre (1963) for the case of short washout times, and Machta (1960). The concentrations of Pb-210 and Po-210 in surface air and Pb-210 in rainwater have been measured continuously since 1961. The ratio of Po-210/Pb-210 exhibits a seasonal variation during 1962 and 1963: this might be attributed to artificial production of Pb-210 during the weapon tests of 1961-2. An estimate has been obtained of the global deposition of Pb-210. DOI: 10.1111/j.2153-3490.1966. tb00254.x
Gas kinematics and dynamics: Spiral structure and cloud formation in disk galaxies

Title of Dissertation: Gas Kinematics and Dynamics: Spiral Structure and Cloud Formation in Disk Galaxies Rahul Shetty, Doctor of Philosophy, 2007 Dissertation directed by: Professor Eve C. Ostriker Department of Astronomy Star formation in disk galaxies occurs as a result of various physical mechanisms acting in the interstellar medium. Molecular clouds, the sites of star formation, grow from the diffuse interstellar medium due to a combination of gas self-gravity, galactic rotation, and magnetohydrodynamic effects. Observations have suggested that spiral arms promote star formation by compressing gas as it flows through the arms. When the density is sufficiently high, gravitational instability causes gas to collapse and form clouds. After the formation of stars within such clouds, the subsequent evolution of the cloud and the surrounding ISM is dramatically altered. Feedback effects such as stellar winds, ionizing radiation, and supernova explosions inject energy into the surrounding medium; these processes may halt the collapse, and perhaps even destroy the natal clouds. In this thesis, we study the flow of gas through the spiral arms of the grand-design galaxy M51; additionally, through numerical simulations, we model the growth of clouds in spiral arms and investigate the effect of feedback on cloud formation and disk dynamics. We use both observational and numerical methodologies to study gas kinematics and dynamics in spiral galaxies. Using CO and H α velocity fields we study spiral arm streaming in M51. With numerical simulations, we investigate gravitational instability in disk galaxies, which leads to the growth of clouds. In order to study the subsequent evolution of the gaseous disk, we include feedback effects that return dense cloud gas back into the surrounding ISM. We find that the simple description of a stationary spiral pattern in M51 is inaccurate. Our numerical models suggest that sheared features can grow regardless of the presence of grand-design spiral structure, but that spiral perturbations cause arm clouds to grow, along with distinct spiral substructure. We find that feedback can significantly affect the evolution of the gaseous disk. We suggest that the disk thickness is important in setting the rate at which stars form. The turbulence scale also needs to be considered, both for the growth of clouds and stars, as well as for the evolution of any large-scale spiral pattern. Gas Kinematics and Dynamics: Spiral Structure and Cloud Formation in Disk Galaxies
The evolution of sub-mesoscale, coherent vortices on the β-plane

Abstract An investigation is made of the evolution of small-scale, axisymmetric vortices in a stratified fluid with spatially variable Coriolis parameter. The criteria for smadness are a horizontal scale less than or equal to the first internal radius of deformation and a vertical scale less than or equal to that of the ambient stratification. These circumstances match those of Sub-mesoscale, Coherent Vortices frequently observed in the oceans. The dynamical model is the balance equations, which include various effects of finite Rossby number. The principal topics are the regime of nearly uniform propagation, the development of an equilibrium ratio of vertical and horizontal scales (i.e., Burger number selection), and the occurrence of various types of instability for vortices with extremes in amplitude or shape.
H I emission-absorption experiments toward Galactic H II regions

21 cm atomic hydrogen emission-absorption experiments have been conducted toward 19 Galactic H II regions lying within 1 deg of the Galactic plane. With the exception of one source, absorption has been detected at the hydrogen recombination line velocity of each H II region. 141 absorption features at positive LSR velocities have been identified. If the observed absorption is solely due to cold gas attenuating thermal continuum, these data can provide kinematic distance estimates for the H II regions. Approximately 40 percent of the absorption features are correlated with (C-13)O emission. Nearly 17 percent of the (C-13)O lines appear not to be associated with H I absorption. The derived spin temperatures for these features range from 25 to about 350 K. The measured optical depths are strongly correlated with the spin temperatures. 14 refs.
The COMA/A1367 Supercluster and Its Environs

The three-dimensional galaxy distribution in the region of space surrounding the two rich clusters Coma and A1367 is analyzed by using a nearly complete redshift sample of 238 galaxies with m, 20 h-l Mpc where there appear to be no galaxies whatever. Since tidal disruption is probably responsible for the isolated component of supercluster galaxies, the observations suggest that all galaxies are (or once were) members of groups or clusters. A number of related topics with more general significance are also discussed. (1) The size-to-separation ratio for foreground groups indicates that the redshift of group formation is z 8 9. (2) There is a general correlation between the volume mass density of a galaxy system and the morphologies of the component galaxies. (3) Finally, we speculate that all clusters of richness class z 2 2 are located in superclusters. Subject headings: galaxies : clusters of galaxies: redshifts
Room‐temperature pulsed oscillation of GaAlAs/GaAs surface emitting injection laser

We report the first room‐temperature pulsed oscillation of a GaAlAs/GaAs surface emitting injection laser. A ring electrode of which the outer/inner diameter is 20 μm/10 μm has been introduced to distinguish a mirror and Ohmic contact in order to increase the reflectivity. The threshold current was as low as 510 mA at room temperature under pulsed conditions. The cavity length was 7 μm and single longitudinal mode operation was achieved at λ=8740 A against the temperature variation of 80 K.
A computationally convenient unit root test with covariates, conditional heteroskedasticity and efficient detrending

When testing for a unit root in a time series, in spite of the well‐known power problem of univariate tests, it is quite common to use only the information regarding the autoregressive behaviour contained in that series. In a series of influential papers, Elliott et al. (Efficient tests for an autoregressive unit root, Econometrica 64, 813–836, 1996), Hansen (Rethinking the univariate approach to unit root testing: using covariates to increase power, Econometric Theory 11, 1148–1171, 1995a) and Seo (Distribution theory for unit root tests with conditional heteroskedasticity, Journal of Econometrics 91, 113–144, 1999) showed that this practice can be rather costly and that the inclusion of the extraneous information contained in the near‐integratedness of many economic variables, their heteroskedasticity and their correlation with other covariates can lead to substantial power gains. In this article, we show how these information sets can be combined into a single unit root test.
Spectral self-concordant functions in the space of two-by-two symmetric matrices

We show that given a two-variable, symmetric, ϑ-self-concordant function f, the spectral function F = f ○ λ is 2(1 + 3ϑ)-self-concordant. Correspondingly, if f is ϑ-self-concordant barrier, then 4(1 + 3ϑ)2 F is a 4(1 + 3ϑ)2ϑ-self-concordant barrier.
Optimal wholesale price for producer in supply chain under newsboy environment

The lifecycles of technology-based products are rapidly becoming shorter through endless technological innovation. As a result, researchers and practitioners paid much attention on operations management issues for newsvendor-type products. However, due to the globalisation of market and keen competition, optimising supply chain decisions becomes very important and many researchers have turned their attention to the supply chain management for newsvendor-type products. In this paper, a model for supply chain with one producer and multiple retailers is considered. The retailers order quantities of the product based on newsvendor rule and the producer adjusts the production run accordingly. The purpose of the developed model is to find the optimal wholesale price which maximises the expected profit of the producer.
Working Capability Analysis of Stewart Platforms

Working capability analysis of planar and spatial Stewart platforms with unilateral constraints on actuator length is carried out using numerical methods based on analytical criteria for the boundary of the accessible output set. Restrictions on achievable motion at singular configurations associated with points interior to the accessible output set are also analyzed. Since movement of the working point on a spatial Stewart platform occurs in three-dimensional space, the boundary of the accessible output set is a two-dimensional surface. Numerical methods used in this analysis map one-dimensional solution sets, permitting the boundary of the accessible output set to be characterized by a family of one dimensional generators. Motion control restrictions inside the accessible output set are similarly characterized by families of interior singular curves, and barriers to motion control across surfaces defined are analyzed.
Design of a micromachined pressure sensor for endoscopic graspers

A micromachined pressure sensor that is suitable for integrating on the tip of the grasper of an endoscopic surgical instrument is presented. Device operation to detect the pressure applied on the body tissues during endoscopic surgery is based on the change in the capacitance between a 5 micrometers thin boron doped silicon membrane and 1 micrometers thick Aluminium electrodes sputtered inside 15 micrometers deep cavities etched in glass. The design, structural optimization for obtaining high sensitivity and the fabrication process for the device are presented. The device has a peak sensitivity of 500 pFmm2/N. The range of the pressure sensor is from 0.01 N/mm2 up to 0.1 N/mm2 which is suitable for measuring the pressure on various tissues inside the body during endoscopic surgery. Since the device simulates the teeth like surface of the existing grasper it is possible to integrate the device on the tip of the grasper of the endoscopic surgical instrument.
On the skewness of sea-surface elevation

Surface skewness is a statistical measure of the vertical asymmetry of the air-sea interface – exemplified by the sharp crests and rounded troughs of surface gravity waves. Some authors have proposed a constant ratio between surface skewness and the ‘significant slope’ of the waves. Here it is shown theoretically that no such simple relation is to be expected. Wave records are of at least two different types; Eulerian (as made with a fixed probe) or Lagrangian (as with a free-floating buoy). The corresponding statistical properties are examined. At first sight it might appear that the degree of skewness in corresponding records would be different. However it is shown that to lowest order the skewness is invariant; only the apparent mean level is different, at second order.
Structure in Host Galaxies of Steep-Spectrum Radio QSOs

We present deep imaging in two bands of five high-luminosity steep-spectrum radio QSOs. The set of broadband filters we have used has been specifically designed to exclude contamination from all strong emission lines found in extended emission regions around QSOs. For four of the objects, we also have deep R-band imaging. Because we generally do not have suitable stars for determining the point-spread function within our limited fields, we have developed a simple technique for detecting asymmetric structure close to the QSO by using a rotational average of the QSO profile itself.
Graphene based field effect transistor for the detection of ammonia

Graphene synthesized by chemical vapor deposition has been used to fabricate the back-gated field effect transistor to study the sensing of ammonia (NH3) in ppm levels. Graphene has been synthesized directly on a target substrate using a thin Cu film as a catalyst, which has several advantages over deposition of graphene on Cu foil followed by a transferring process to another substrate. Raman spectroscopy was used to monitor the quality of the deposited graphene films on SiO2/Si substrates. The adsorption/desorption behavior of NH3 on graphene in dry air was analyzed from the progressive shift of the Dirac peak at smaller/larger gate voltages based on different time exposures to different concentrations of NH3. The relative change in the shift of the Dirac peak was consistent with a small charge transfer (0.039 ± 0.001 electrons per molecule at room temperature). The response of the device was found to increase with increasing NH3 concentrations and operating temperatures. The dependence of device respon.
Exploiting sub-pixel edge detection methods with high density sampling to provide .001 pixels rigid target localization

An empirical method for Canny filter optimization is explored and applied to the problem of measuring rigid motion between targets for nanometer motion detection. Operating with an image space pixel size of 3 μm, we are able to obtain static target localization to 6 nm at 2σ variation. To discriminate target roughness from sub-pixel measurement noise we use a Laplacian filter method. To extend the resolution beyond the limits of a single sub-pixel sample we use multiple adjacent edge locations along a single target to statistically reduce the overall resolution. With sufficient samples we obtain near . 001 pixels resolving power. Even at this resolution we have not reached the limits of sampling which are possible from simultaneously sampling sets of parallel lines allowing for future refinement of method to localize well below . 001 pixels.
Compact 3D flash lidar video cameras and applications

The theory and operation of Advanced Scientific Concepts, Inc.'s (ASC) latest compact 3D Flash LIDAR Video Cameras (3D FLVCs) and a growing number of technical problems and solutions are discussed. The solutions range from space shuttle docking, planetary entry, decent and landing, surveillance, autonomous and manned ground vehicle navigation and 3D imaging through particle obscurants.
Evolution of sheared flow structure in visco-elastic fluids

A visco - elastic fluid is represented frequently by the Generalized Hydrodynamic (GHD) model. Unlike Navier Stokes fluid such a system supports transverse shear waves. Thus, while a sheared flow structure in a Navier Stokes fluid system is marred by the development of the Kelvin - Helmholtz (KH) instability alone, in the case of visco - elastic GHD fluid, a shear flow pattern can be expected to be effected by both, namely the KH instability and the emission of transverse shear waves. The manuscript explores this feature in detail. For this purpose (a) the modifications on the KH instability mode due to strong correlations in linear as well as nonlinear regime and (b) the conditions under which either the KH mode and/or the transverse shear wave emission dominates have been identified in the manuscript.
On the exponential solution of differential equations for a linear operator

The present investigation was stimulated by a recent paper of K. 0. Friedrichs 113, who arrived at some purely algebraic problems in connection with the theory of linear operators in quantum mechanics. In particuIar, Friedrichs used a theorem by which the Lie elements in a free associative ring can be characterized. This theorem is proved in Section I1 of the present paper together with some applications which concern the addition theorem of the exponential function for non-commuting variables, the so-called BakerHausdorff formula. Section I contains some algebraic preliminaries. It is of a purely expository character and so is part of Section 111. Otherwise, Section 111 deals with the following problem, also considered by Friedrichs: Let A( t ) be a linear operator depending on a real variable 1. Let Y(t) be a second operator satisfying the differential equation
The design of artificial receptors for complexation and controlled aggregation

Simple synthetic receptors have been developed that function via directed hydrogen bonding interactions in highly competitive solvents. Strong binding of this type in polar solvents may be due to a number of factors including favourable secondary hydrogen bonding interactions between the carboxylate and urea, the use of charged H-bond acceptors, an inefficient solvation of the closely spaced H-bond donor sites in the urea, and an entropically favourable release of solvent and/or counterion molecules on complex formation. We also demonstrate that these types of interactions can be used to induce, both in solution and the solid state, discrete 2 + 2 aggregates stabilized by a network of hydrogen bonds.
Variability of Hailstorms on the South African Plateau

Abstract Detailed climatological studies of hailstorms on the South African plateau have been made using a dense network of voluntary observers. Hailstone structures have been investigated and, since 1971, radar observations have been used to study storm characteristics. Results are given for the frequency of hailstorm occurrence, characteristics of hailfalls at a point, hail paths, types of storms, radar characteristics and hailstone trajectories. Practically all features showed great variability, the magnitude of which is given whenever possible. Application of the results to the design of a hail suppression experiment is briefly discussed.
Achieving high free electron mobility in ZnO:Al thin films grown by reactive pulsed magnetron sputtering

The study is focused on the improvement of the free electron mobility in Al-doped ZnO films grown by reactive pulsed magnetron sputtering. At optimum growth conditions low-absorbing films are obtained with a Hall mobility of 46 cm2 V−1 s−1, a free electron density of 6.0×1020 cm−3, and an electrical resistivity of 2.26×10−4 Ω cm. The relation between the mobility and free electron density for different growth conditions is discussed in terms of ionized impurity scattering, impurity clustering, and grain boundary limited transport.
Light scattering from binary optics

Current pattern data formats for electron beam lithography are specifically designed to meet the needs of the VLSI industry. As a result, pattern data file size is often the limiting factor in the production of a binary computer generated hologram and not the spatial bandwidth product. This paper explores one alternate pattern data format that facilitates the full utilization of the e-beam machine's spatial bandwidth product without introducing prohibitive amounts of pattern data. The pattern data format uses two well established data compression techniques specifically tailored to remove the redundancies present in holographic fringe patterns.
A new high-resolution photomask inspection system for contamination detection

STARlight2+TM (SL2+) is a new high-resolution contamination inspection system based upon the KLA-Tencor TerascanHR platform. Building upon the proven technology of STARlightTM (SL2), SL2+ uses transmitted and reflected images to detect potentially yield-limiting contamination defects on photomasks for wafer fabs and mask shops. It extends the contamination inspection capability to the 32nm logic/45nm Half Pitch (HP) technology nodes using the newly developed 72nm pixel image resolution as well as a significantly improved rendering model in the algorithm. In this paper, we present inspection results on a wide variety of photomasks, spanning the 32nm to 110nm technology nodes, in the recently concluded period of Alpha tests on the SL2+ system. The test results show that the sensitivity and the inspection capability of the new SL2+ system have been greatly improved. Such improvement enables wafer fabs and mask shops to inspect and qualify photomasks for 32nm node development and 45nm node production.
Analysis and Characterization of Flow-Generated Sound

Flow-generated sound and velocity distributions of free flows are characterized by frequency spectra (FFT and several spectra from the octave spectrum over the one-third octave spectrum till the narrow band spectrum), by the PSD (power spectrum density) and wavelets. Whereas previously, flow processes are characterized by the average velocity, by the local velocity, if needed also by the three-dimensional velocity distribution and the degree of turbulence, also the flows and particular velocity distributions could be described by the acoustic pressure and level, by the power spectrum density and by wavelets, especially by the Gabor-Wavelet, as shown below.