Parameter Estimation from Near Stall Flight Data using Conventional and Neural-based Methods

The current research paper is an endeavour to estimate the parameters from near stall flight data of manned and unmanned research flight vehicles using conventional and neural based methods. For an aircraft undergoing stall, the aerodynamic model at these high angles of attack becomes non linear due to the influence of unsteady, transient and flow separation phenomena. In order to address these issues the Kirchhoff’s flow separation theory was used to incorporate the nonlinearity in the aerodynamic model in terms of flow separation point and stall characteristic parameters. The classical Maximum Likelihood (MLE) method and Neural Gauss-Newton (NGN) method have been employed to estimate the nonlinear parameters of two manned and one unmanned research aircrafts. The estimated static stall parameter and the break point, for the flight vehicles under consideration, were observed to be consistent from both the methods. Moreover the efficacy of the methods is also evident from the consistent estimates of post stall hysteresis time constant. It can also be inferred that the considered quasi steady model is able to adequately capture the drag and pitching moment coefficients in the post stall regime. The confidence in these estimates have been significantly enhanced with the observed lower values of Cramer-Rao bounds. Further the estimated nonlinear parameters were validated by performing a proof of match exercise for the considered flight vehicles. Interestingly the NGN method, which doesn’t involve solving equations of motion, was able to perform on a par with the MLE method

N-(2-Formyl­phen­yl)benzene­sulfonamide

In the title compound, C13H11NO3S, the two aromatic rings are oriented at an angle of 88.18 (8)°. Intra­molecular N—H⋯O and C—H⋯O hydrogen bonds are observed, each of which generates an S(6) ring motif. In the crystal, mol­ecules are linked into C(7) chains along [010] by inter­molecular C—H⋯O hydrogen bonds. The structure is further stabilized by inter­molecular C—H⋯π inter­actions involving the sulfonyl-bound phenyl ring

Diethyl 2-(2-nitro­benzyl­idene)malonate

In the title compound, C14H15NO6, the ethoxy­carbonyl groups adopt extended conformations. In the crystal, mol­ecules are linked into centrosymmetric dimers via pairs of C—H⋯O hydrogen bonds with a R 2 2(20) motif

Recognition of Characters and Patterns using Neural Network

This paper describes the recognition of handwritten characters using Probabilistic neutral network classifier. Identification of hand written characters requires the large number of data sets. The individual characters are identified using Segmentation and the feature analysis is done through the grey-level co-occurrence matrix. Finally the PNN Classifier is used to classify the each individual characters based on the stored data set

Study of electrically active defects in epitaxial layers on silicon

Electrically active defects in silicon-based epitaxial layers on silicon substrates have been studied by Deep-Level Transient Spectroscopy (DLTS). Several aspects have been investigated, like, the impact of the pre-epi cleaning conditions and the effect of a post-deposition anneal on the deep-level properties. It is shown that the pre-cleaning thermal budget has a strong influence on the defects at the substrate/epi layer interface. At the same time, a post-deposition Forming Gas Anneal can passivate to a large extent the active defect states. Finally, it is shown that application of a post-deposition anneal increases the out-diffusion of carbon from a Si:C stressor layer into the p-type CZ substrate

5-Methyl­phenanthro[2,3-b]thio­phene

The title compound, C17H12S, which crystallises with two molecules in the asymmetric unit, features four fused rings forming an essentially planar mol­ecule, with maximum deviations from the mean plane of 0.078 (2) and 0.080 (2) Å for C atoms of the thio­phene and phenanthrene groups in both the mol­ecules. The crystal packing features weak C—H⋯π inter­actions

1-(Phenyl­sulfon­yl)benzo[1,2:2′,3′]thieno[5′,4′-b]carbazole

In the title compound, C24H15NO2S2, the ring system composed of the five fused rings is almost planar (r.m.s. deviation for all non-H atoms = 0.056 Å). The dihedral angle between the fused ring system and the phenyl ring is 83.4 (9)°. The crystal packing is stabilized by C—H⋯π and π–π inter­actions between parallel ring systems [centroid–centroid distances = 3.526 (3), 3.877 (3) and 3.712 (3) Å]

Phen­yl(3-methyl-1-phenyl­sulfonyl-1H-indol-2-yl)methanone

In the title compound, C22H17NO3S, the N atom of the indole ring system deviates by 0.031 (3) Å from a least-squares plane fitted through all nine non-H ring atoms. The geometry around the S atom can be described as distorted tetra­hedral. As a result of the electron-withdrawing character of the phenyl­sulfonyl groups, the N—Csp 2 bond lengths are longer than the typical mean value for N atoms with a planar configuration

Sea grass like arranged TiO2 nanorods sensitized by natural dyes for solar cell applications

Rutile phase sea grass like arranged TiO2 nanorods have been synthesized by low temperature template free hydrothermal method. These TiO2 nanorods have been sensitized by flowers of Sesbania grandiflora, leaves of Camellia sinensis and roots of Rubia tinctorum. The sensitized TiO2 nanorods based films have been used as photoanode in natural dye sensitized solar cells. The films were photoelectrochemically active and the fabricated solar cells had short circuit photocurrent densitiy(JSC) lying in the range of 3.7mAcm-2 to 4.7mAcm-2. The efficiency of the fabricated natural dye sensitized solar cells were found to lie in the range of 0.6% to 1.036% respectively

Enhanced performance of natural dye sensitised solar cells fabricated using rutile TIO2 nanorods

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Due to the lower cost, natural dye molecules are good alternatives for the ruthenium based sensitizers in the dye-sensitized solar cells. In this article, we have reported the natural sensitizer based dye-sensitized solar cells fabricated using TiO2 nanorods. Rutile phase TiO2 nanorods have been synthesized by template free hydrothermal method which results in TiO2 nanorods in the form of acropora corals. These TiO2 nanorods have been sensitized by flowers of Sesbania grandiflora, leaves of Camellia sinensis and roots of Rubia tinctorum. The maximum conversion efficiency of 1.53% has been obtained for TiO2 nanorods based solar cells sensitized with the leaves of Camellia sinensis.The flowers of Sesbania grandiflora and roots of Rubia tinctorum sensitized TiO2 nanorods based solar cells exhibited an efficiency of 0.65% and 1.28% respectivel