Application of Noise Reduction Technique in the Inverse Analysis Using Kalman Filter

Abstract

The inverse techniques usually employ the sensor measurement to estimate the unknown quantities. Regardless of sensor accuracy, the measurements contain some degrees of uncertainty and error, inadvertently. Inasmuch as, the inverse problems are ill-conditioned in general term, the measurement errors cause instabilities, perturbations, and excursions in the solution procedure. To handle the noise difficulties, a novel approach is proposed in the current study. In this method, the measurement errors are filtered to alleviate the noise priori to utilization of inverse method. The Kalman filter is implemented to remove the noise from the original sensor readings. Thereafter, the Levenberg–Marquardt method is implemented to predict the unknown. To evaluate the accuracy and robustness of the developed approach, a high nonlinear test case containing moving boundary heat conduction problem is investigated. Comparing the obtained results illustrates the improvement of inverse solution procedure by employing the noise filtering technique.     

Inverse boundary design of a radiant furnace with diffuse-spectral design surface

An optimization technique is applied to inverse design of radiative furnaces with diffuse-spectral surfaces. The variation of emissivity with respect to the wavelength is approximated by considering a set of spectral bands with constant emissivities and then the radiative transfer equation is solved by the net radiation method for each band. The conjugate gradient method is used for estimation of temperatures over reflector and heater surfaces. The sensitivity problem is approximated by differentiation of the radiative transfer equation with respect to the unknown variables. The performance of the present method is evaluated by comparing the results with the results obtained by considering a diffuse-gray design surface.     

Inverse Reconstruction of Path-Length κ-Distribution in a Plane-Parallel Radiative Medium

An inverse methodology is used to reconstruct the absorption coefficient distribution in a plane-parallel, absorbing–emitting medium with gray-diffuse walls, from the knowledge of exit intensity over the walls. The discrete transfer and conjugate gradient methods, respectively, are used to solve the direct and inverse problems. The sensitivity problem is solved by an efficient approach. The results show that the absorption coefficient distribution can be recovered well even for noisy data.     

Estimation of applied heat flux at the surface of ablating materials by using sequential function specification method

Journal of Mechanical Science and Technology - This paper presents an inverse analysis in one-dimensional ablation problem with the presence of a moving boundary to estimate the unknown applied...     

Structural,Optical, and Magnetic Properties of Nickel‐Doped Tin Dioxide Nanoparticles Synthesized by Solvothermal Method

We have successfully synthesized Sn_1?xNi_xO₂ (0.05 ≤ x ≤ 0.15) solid solutions in order to study their structural, optical, and magnetic properties at different Ni concentrations. X‐ray diffraction showed monophasic and crystalline tetragonal structure. The shifting of peaks toward higher angle is attributed to the incorporation of Ni²⁺ ions in SnO₂ host lattice. Particle growth restrained upon Ni‐doping and found to be in the range of 8–12 nm. Ni‐doped SnO₂ nanoparticles show blue shift in band gap studies, which is found to be in the range of 3.9–4.1 eV. High surface areas have been achieved for these solid solutions, which come out to be 130, 200, 457, 497, and 680 m²/g, respectively. The solid solutions exhibit paramagnetic behavior along with antiferromagnetic exchange coupling.     

Effect of miscibility on migration of third component in star‐like co‐continuous and disperse‐within‐disperse mixed brushes

Novel ternary mixed‐brush single crystals were designed with disperse‐within‐disperse and star‐like co‐continuous morphologies based on poly(ethylene glycol) (PEG)‐b‐polystyrene (PS)/PEG‐b‐poly(methyl methacrylate) (PMMA)/PEG‐b‐polyaniline (PANI) and PEG‐b‐PS/PEG‐b‐PMMA/PEG‐b‐(poly(?‐caprolactone) (PCL) or poly(l ‐lactide) (PLLA)) block copolymers, respectively. In the disperse‐within‐disperse ternary mixed brushes, PANI nanorods were dispersed within the matrix (PS)–dispersed (PMMA) amorphous brushes. The flexibility and rigidity of brushes mainly affected the ultimate morphology and arrangement of amorphous coiled brushes in the vicinity of PANI nanorods. In addition, the migration of PCL and PLLA crystallizable brushes was evident into PMMA phases dispersed in the PS matrix, leading to star‐like co‐continuous patterns of PCL and PLLA brushes. This phenomenon was related to the miscibility of crystallizable PCL and PLLA brushes with the PMMA phase. The migration of crystallizable PCL and PLLA brushes increased the size of PMMA domains in the star‐like co‐continuous patterns. Despite the larger osmotic pressure of PLLA brushes, their higher miscibility with PMMA chains reflected the greater PMMA dispersal and wider PLLA star‐like branches. © 2017 Society of Chemical Industry     

Towards skin tissue engineering using poly(2-hydroxy ethyl methacrylate)-co-poly(N-isopropylacrylamide)-co-poly(ε-caprolactone) hydrophilic terpolymers

Poly(2-hydroxy ethyl methacrylate)-co-poly(N-isopropylacrylamide)-co-poly(ε-caprolactone) (PHEMA-co-PNIPAAm-co-PCL) terpolymers and polyaniline (PANI) were applied to develop hydrophilic, conductive, and biocompatible fibroblast scaffolds. Reversible addition of fragmentation chain transfer (RAFT) and ring opening polymerizations were the synthesis methods. PHEMA and PNIPAAm segments reflected hydrophilicity and biocompatibility, PCL led to appropriate mechanical characteristics, and presence of PANI induced conductivity to scaffolds. Scaffolds imitated natural microenvironment of extra cellular matrix (ECM) to regulate cell attachment, proliferation, and differentiation for electrical conductivity (0.04?S cm^?1) and hydrophilicity (50?±?5°). In vitro cytocompatibility investigations performed over 168?h indicated that nanofibers were non-toxic to mouse fibroblast L929 cells.     

A focus on polystyrene tacticity in synthesized conductive PEDOT:PSS thin films

Poly(3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) is a transparent conductive material and a good candidate for being employed as substitute for indium tin oxide (ITO) in reducing the production costs of organic solar cells. To enhance the performance of organic devices, an improving in the conductivity of PEDOT:PSS is crucial and using the solvent additive rises the electrical conductivity by the optimization of the film morphology. The studies have only focused on the relationship between the electrical conductivity of thin films and the crystallinity of PEDOT, and it is also found that the high conductivity is observed in the highly crystalline samples. This study focused on the effect of tacticity of PS on the conductivity of PEDOT:PSS films. First, atactic and isotactic polystyrenes were sulfonated and the complexes of PEDOT:PSS were synthesized. The N-methylpyrrolidone (NMP), as a secondary dopant, was then added to the complexes and conductivity enhancement was investigated in various annealing times. The obtained films were characterized by atomic force microscopy, X-ray diffraction, four point probe resistivity measurement system, UV–visible spectroscopy, FT-IR, and cyclic voltammetry. The electrical conductivity of PEDOT:iPSS films synthesized by the isotactic polystyrene was ~ 0.68 S/cm and by adding 5 wt% NMP into PEDOT:PSS solution, the conductivity of the annealed thin layers increased more than 10-folds (~ 7.73 S/cm) at an appropriate temperature.