Inverse Method

Abstract—In Earth observation programs there is a need of passive low frequency (L-band) measurements to monitor soil moisture and ocean salinity with high spatial resolution 10–20 Km, a radiometric resolution of 1K and a revisit time of 1–3 days [1]. Compared to total power radiometers ...

Effect of Mold Coating Materials and Thickness on Heat Transfer in Permanent Mold Casting of Aluminum Alloys A. HAMASAIID, MS DARGUSCH, CJ DAVIDSON, S. TOVAR, T. LOULOU, F. REZAI¨-ARIA, and G. DOUR ... These coatings maintain mechanical integrity and prevent ...

This study proposes a new method to determine the mechanical properties of human skin by the use of the indentation test [Pailler-Mattei, 2004. Caractérisation mécanique et tribologique de la peau humaine in vivo, Ph.D. Thesis, ECL-no. 2004-31; Pailler-Mattei, Zahouani, 2004. Journal of Adhesion Science and Technology 18, 1739-1758]. The principle of the measurements consists in applying an in vivo compressive stress [Zhang et al., 1994. Proceedings of the Institution of Mechanical Engineers 208, 217-222; Bosboom et al., 2001. Journal of Biomechanics 34, 1365-1368; Oomens et al., 1984. Selected Proceedings of Meetings of European Society of Biomechanics, pp. 227-232; Oomens et al., 1987. Journal of Biomechanics 20(9), 877-885] on the skin tissue of an individual's forearm. These measurements show an increase in the normal contact force as a function of the indentation depth. The interpretation of such results usually requires a long and tedious phenomenological study. We propose a new method to determine the mechanical parameters which control the response of skin tissue. This method is threefold: experimental, numerical, and comparative. It consists combining experimental results with a numerical finite elements model in order to find out the required parameters. This process uses a scheme of extended Kalman filters (EKF) [Gu et al., 2003. Materials Science and Engineering A345, 223-233; Nakamura et al., 2000. Acta Mater 48, 4293-4306; Leustean and Rosu, 2003. Certifying Kalman filters. RIACS Technical Report 03.02, 27pp. http://gureni.cs.uiuc.edu/~grosu/download/luta + leo.pdf; Welch and Bishop, An introduction to Kalman filter, University of North Carolina at Chapel Hill, 16p. http://www.cs.unc.edu/~welch/kalman/]. The first results presented in this study correspond to a simplified numerical modeling of the global system. The skin is assumed to be a semi-infinite layer with an isotropic linear elastic mechanical behavior [Zhang et al., 1994. Proceedings of the Institution of Mechanical Engineers 208, 217-222] This analysis will be extended to more realistic models in further works.

This chapter discusses the Junjappa-I1a (JI)-heteroaromatic annulation, which is a new general α-oxoketene dithioacetals mediated inverse method for the synthesis of benzo/condensed heterocycles and related heteroaromatization processes. In principle, a wide variety of five and six membered heterocycles bearing a ring C–C double bond with an exocyclic methyl group can be used as allyl anion precursors for benzoheterocycles. The α-oxoketene dithioacetals employed in this work as three carbon 1,3-biselectrophilic components are drawn from various active methylene ketones. The corresponding α-oxoketene N,S- and O,S-acetals which are usually derived from α-oxoketene dithioacetals are also described. The chapter also discusses the reaction of 3-Methyl-5-1ithiomethylisoxazole with α-oxoketene dithioacetals—a general method for the synthesis of substituted and fused 1,2-benzisoxazoles. It also discusses Reaction of 1-N-carboxy-2-1ithiomethylindole Dianion with α-oxoketene dithioacetals—a new method for the synthesis of 2,3- substituted and fused carbazoles. A reaction of 3-lithiomethyl-2-methyl-l-phenylpyrazolin-5-one with α-oxoketene dithioacetals—a new general method for the synthesis of 1,2-disubstituted indazolones and their condensed analogs is also discussed. The chapter also presents the reaction of 6-lithiomethyl-l,3-dimethyluracil with α-oxoketene dithioacetals—one pot new general synthesis of substituted quinazolines; reaction of 1-methylpyrrole-2-acetonitrile with α-oxoketene dithioacetals—new efficient synthesis of highly substituted indoles; reaction of indole-3-acetonitrile with α-oxoketene dithioacetals—a new efficient general method for the synthesis of 1,2- substituted and condensed carbazoles; and reaction of thiophene-2-acetonitrile 57 and thiophene-3-acetonitrile with α-oxoketene dithioacetals—an efficient new general synthesis of highly substituted benzo[b]thiophenes.

Natural materials are becoming a valid option for sound absorption treatments. In particular, among them, natural fibers have received increasing attention given their good thermal insulation properties, lack of harmful effects on health, and availability in large quantities. This paper discusses an inverse method to predict the acoustical properties of nine natural fibers. Six vegetative fibers: kenaf, wood, hemp, coconut, straw, and cane; one animal fiber, sheep wool; recycled cardboard; and granular cork are investigated. The absorption coefficient and the flow resistance for samples of different thickness have been measured. Moving from the Delany-Bazley model, this study compares the impedance tube results with the theoretically predicted ones. Then, using a least-square fit procedure based on the Nelder-Mead method, the coefficients that best predict both the acoustic impedance and the propagation constant laws are calculated. The inverse approach used in this paper allows to determine different physical parameters and to obtain formulas to include the investigated natural fibers in software modelling for room acoustics applications.

A method for the radial analysis of the plasma torch produced by the axial injection torch device at atmospheric pressure is proposed. The method uses a fast high-resolution acquisition set-up including an intensified charge coupled device and an image rotation system, as well as a new data processing procedure based on the Abel inversion technique that provides the radial profile of thin plasmas. Use of the Fernández-Palop smoothing technique significantly reduces distortion in the data profile. The accuracy of the proposed method was assessed by applying it to the estimation of the populations of HeI excited states.

ABSTRACT In structural dynamics superconvergent element models are obtained by eigen-value convergence analysis, or minimizing the discretization errors leading to maximum convergence rates in their eigen-solutions. The element formulations developed by these inverse strategies are obtained in local coordinates. As no shape functions are employed in their development transforming them to global coordinates is a challenge and prevents their use in practical finite element models. To remove this obstacle a new method is proposed to obtain shape functions for superconvergent element models attained directly from the eigen-value convergence analysis or discretization error analysis. The method employs series of trigonometric functions to obtain shape functions corresponding to the superconvergent element formulations. Using the proposed strategy, the shape functions for superconvergent rod, beam and transverse vibration membrane are obtained. It is shown transformation of the superconvergent element formulation to the global coordinates using the obtained shape functions does not affect the eigen-value convergence rates.Highlights► Trigonometric functions are employed to form shape functions of superconvergent element models. ► The shape functions are used to transform the element displacement field to the global coordinates. ► Improvements in estimating the eigen-values are demonstrated in a sectorial vibrating membrane. ► It is shown the accuracy of model is kept unchanged in global coordinates. ► Also higher order of accuracy is achieved compared to the existing formulations in the literature.

The devastating İzmit and Düzce earthquakes were followed by theOrta intra-plate earthquake (MS = 6.1) occurred in the central Anatolianblock on June 6, 2000. The focal mechanism, aftershock distribution andthe field studies (Emre et al., 2000) suggest a movement on a 21-km longDodurga fault striking nearly N-S where the sense of motion is left-lateralstrike-slip with considerable amount of normal component. We applied theconstrained linear finite-fault inversion method of Hartzell and Heaton(1983) to the teleseismic P and SH waveforms to derive a coseismic slipdistribution model for the earthquake. Time windows approach is appliedallowing variable rise times and rupture velocities. The source-rise timefunction is discretized into consecutive time intervals that stand for slipcontribution of individual subfaults. Although no clear surface ruptureswere associated with the earthquake, the resulting slip model suggestscoseismic slip in the order of several tens of centimetres. Our coseismicslip distribution model identifies two slip patches with the followingmaximum slip values: (1) the larger one (42 cm) is located to the southof the hypocenter at depth range of 4–8 km and (2) the smaller one(31 cm) is located just above and north of the hypocenter. Theslip-model yield a seismic moment of 1.0 × 1018 Nm, most of whichis released from the rupture over the depth of 8 km.