Pansharpening multispectral remote sensing data by multiplicative joint nonnegative matrix factorization

Pansharpening aims at combining observable panchromatic and multispectral images to generate an unobservable image with the high spatial resolution of the former and the spectral diversity of the latter. In this paper a new fusion method is proposed. This method, related to linear spectral unmixing (LSU) techniques and based on non-negative matrix factorization (NMF), optimizes, by new iterative–multiplicative update rules, a joint criterion that exploits a spatial degradation model between the two images. The proposed Multiplicative Joint Non-negative Matrix Factorization (MJNMF) approach is applied to synthetic and real data, and its effectiveness in spatial and spectral domains is evaluated with commonly used performance criteria. Experimental results show that the proposed method yields good spectral and spatial fidelities of the pansharpened data. Also, it outperforms those tested from the literature.     

Relaxation dynamic and electrical mobility for poly(methyl methacrylate)‐polyaniline composites

Composites of emeraldine form of polyaniline (PAni) and poly(methyl methacrylate) (PMMA) are prepared by emulsion polymerization method in definite ratios. The chemical structure of the samples and their morphologies have been investigated by different techniques including FTIR, UV–vis, XRD, SEM, and TGA. Enhancement in thermal stability of the obtained composites by PAni additions has been confirmed. Alpha analyzer, in frequency range 0.1 Hz to 20 MHz, was employed to investigate the molecular dynamics of the prepared samples and the accompanied electrical conductivity at temperatures ranging from 223 to 423 K. Conductivity investigations showed that mobility has the more dominant effect on the charge transportation. The dynamic peak at lower temperatures of the PMMA has high activation energy (83.8 kJ/mol). While, Maxwill‐Wagner‐Siller process due to the interfacial polarization in the composites has only 7.5 kJ/mol activation energy. This is a clear indication of the ease of the investigated dynamic. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45415.     

Reactions of unsaturated compounds I. Structure and chromic acid oxidation of the hydrocarbon C17H18 obtained by the dehydration of 1,1-diphenyl-2,2-dimethylpropan-1-ol

Dehydration of the carbinol 1,1-diphenyl-2,2-dimethylpropan-1-ol gives a hydrocarbon C₁₇H₁₈ which was identified as 2-methyl-3,3-diphenylbut-1-ene. Oxidation of C₁₇H₁₈ with chromium trioxide in acetic anhydride gave acetone, acetophenone, benzophenone and α-methyl-β,β-diphenylbutyric acid. Oxidation with chromium trioxide in aqueous sulphuric acid gave acetone, acetophenone, benzophenone and diphenylmethylacetic acid. A tentative explanation for the production of abnormal fission products and α-methyl-β,β-diphenylbutyric acid is given.     

Nd:YAG laser alloying of high-speed steel tools with BN and Ti/BN and the effects on turning performance

A 400 W pulsed Nd:YAG laser was used to surface alloy BN and Ti/BN on AISI M2 steel using hexagonal BN powder and Ti foil (25 μm thickness). The clearance (flank) faces of the single-point tool were laser alloyed using BN and Ti/BN. Optical metallography, scanning electron microscope, Vicker's microhardness and X-ray diffraction were employed to characterize the alloyed layers. The depths of the laser-alloyed zones of BN- and Ti/BN-alloyed tools were about 140 μm and 260 μm respectively. The hardness of the laser-alloyed layer with BN was about 640 HV while that of the alloyed layer with Ti/BN was about 680 HV. The alloyed layers were free from cracks and porosity. Both the alloyed and unalloyed tools were then tested on a 14.7 kW engine lathe to turn AISI 1045 steel workpieces. The results indicated that the tool life of BN-alloyed tools was about 200% higher than that of the unalloyed tools, while the tool life of Ti/BN-alloyed tools was about 260% higher when the tool life criterion was chosen as 0.3 mm flank wear. Also, the tool wear rate was reduced by about 30% and 50% for BN-and Ti/BN-alloyed tools, respectively. The reduction in tool wear of the alloyed tools was attributed to a reduction of the chip-tool contact length (and consequently the reduction of coefficient of friction between the tool and workpiece material) and to the different chip formation mechanisms.     

Boundary control of a parallel-flow heat exchanger by input–output linearization

A design of the control of the internal fluid temperature at the outlet of a parallel-flow heat exchanger by manipulating the inlet external fluid temperature is proposed. The dynamic model of the heat exchanger is given by two partial differential equations that are used without spatial discretization to design the control law. Based on nonlinear control, a state-feedback law that ensures a desired performance of a measured output defined as the spatial weighted average temperature of the internal fluid is derived. Then, in order to control the outlet internal fluid temperature, a control strategy is proposed where an external controller is introduced to provide the set point of the considered measured output by taking as input the error between the outlet internal fluid temperature and its desired set point. As the designed control law is a state feedback of distributed nature, for practical application, a Kalman filter is used to reconstruct the entire state of the system from the measurements of the outlet fluids temperatures. The closed-loop system is shown to be exponentially stable. The validity of the proposed control design is examined in simulation by considering the tracking and perturbation rejection problems.     

On cavitation and macroscopic behaviour of amorphous polymer-rubber blends

The macroscopic behaviour of rubber-modified polymethyl methacrylate (PMMA) was investigated by taking into account the microdeformation mechanisms of rubber cavitation. The dependence of the macroscopic stress–strain behaviour of matrix deformation on the cavitation of rubber particles was discussed. A phenomenological elastic-viscoplastic model was used to model the behaviour of the matrix material, while the rubber particles were modelled with the hyperelasticity theory. A two-phase composite material with a periodic arrangement of reinforcing particles of a circular unit cell section was considered. Finite-element analysis was used to determine the local stresses and strains in the two-phase composite. In order to describe the cavitation of the rubber particles, a criterion of void nucleation is implemented in the finite-element (FE) code. A comparison of the numerically predicted response with experimental result indicates that the numerical homogenisation analysis gives satisfactory prediction results.     

Dynamics of a rotating flexible and symmetric spacecraft using impedance matrix in terms of the flexible appendages cantilever modes

The subject of this work is the dynamics of a rotating spacecraft. The spacecraft is modeled as a main rigid body connected to two flexible solar panels. The orbital motion of the whole spacecraft with a constant angular velocity is considered, interacting with small rigid motions of the main body, and small elastic deformations and infinitesimal vibrations of the solar panels. A continuum approach based on the Rayleigh–Ritz discretization is used to describe the distributed flexibility in the spacecraft. Rayleigh–Ritz discretization functions used are the clamped modes of the solar panels. This method enables us to construct the impedance matrix of the whole system relating to the displacement of the main body and the external torque. A spectral expansion of this impedance matrix, in terms of these clamped modes is obtained in the frequency domain. The numerical results presented show that for small values of orbital angular velocity, the vibration motion frequencies of the flexible parts (solar panels) are not perturbed substantially. Moreover, when great values of orbital angular velocity are simulated, these frequencies change considerably. The present investigation based on the Rayleigh–Ritz discretization shows the effect of the interaction between the orbital motion of the whole spacecraft and the vibration motions of the flexible parts.     

Range image segmentation using local approximation of scan lines with application to CAD model acquisition

Abstract. Automatic acquisition of CAD models from existing objects requires accurate extraction of geometric and topological information from the input data. This paper presents a range image segmentation method based on local approximation of scan lines. The method employs edge models that are capable of detecting noise pixels as well as position and orientation discontinuities of varying strengths. Region-based techniques are then used to achieve a complete segmentation. Finally, a geometric representation of the scene, in the form of a surface CAD model, is produced. Experimental results on a large number of real range images acquired by different range sensors demonstrate the efficiency and robustness of the method. Received: 1 August 2000 / Accepted: 23 January 2002 Correspondence to: I. Khalifa