1,209 research outputs found
Spectrophotometric Determination of Iron(II) and Cobalt(II) by Direct, Derivative, and Simultaneous Methods Using 2-Hydroxy-1-Naphthaldehyde-p-Hydroxybenzoichydrazone
Optimized and validated spectrophotometric methods have been proposed for the determination of iron and cobalt individually and simultaneously. 2-hydroxy-1-naphthaldehyde-p-hydroxybenzoichydrazone (HNAHBH) reacts with iron(II) and cobalt(II) to form reddish-brown and yellow-coloured [Fe(II)-HNAHBH] and [Co(II)-HNAHBH] complexes, respectively. The maximum absorbance of these complexes was found at 405 nm and 425 nm, respectively. For [Fe(II)-HNAHBH], Beer's law is obeyed over the concentration range of 0.055–1.373 μg mL−1 with a detection limit of 0.095 μg mL−1 and molar absorptivity ɛ, 5.6 × 104 L mol−1 cm−1. [Co(II)-HNAHBH] complex obeys Beer's law in 0.118–3.534 μg mL−1 range with a detection limit of 0.04 μg mL−1 and molar absorptivity, ɛ of 2.3 × 104 L mol−1 cm−1. Highly sensitive and selective first-, second- and third-order derivative methods are described for the determination of iron and cobalt. A simultaneous second-order derivative spectrophotometric method is proposed for the determination of these metals. All the proposed methods are successfully employed in the analysis of various biological, water, and alloy samples for the determination of iron and cobalt content
The effects of rotational flow, viscosity, thickness, and shape on transonic flutter dip phenomena
The transonic flutter dip phenomena on thin airfoils, which are employed for propfan blades, is investigated using an integrated Euler/Navier-Stokes code and a two degrees of freedom typical section structural model. As a part of the code validation, the flutter characteristics of the NACA 64A010 airfoil are also investigated. In addition, the effects of artificial dissipation models, rotational flow, initial conditions, mean angle of attack, viscosity, airfoil thickness and shape on flutter are investigated. The results obtained with a Euler code for the NACA 64A010 airfoil are in reasonable agreement with published results obtained by using transonic small disturbance and Euler codes. The two artificial dissipation models, one based on the local pressure gradient scaled by a common factor and the other based on the local pressure gradient scaled by a spectral radius, predicted the same flutter speeds except in the recovery region for the case studied. The effects of rotational flow, initial conditions, mean angle of attack, and viscosity for the Reynold's number studied seem to be negligible or small on the minima of the flutter dip
Alkaline Protease Bioprocess Optimization through Response Surface Methodology for Alkaliphilic Bacillus subtilis SHmIIIa Mutant Strain from Warangal-Telangana
The present investigations were carried out to enhance the alkaline protease production by a mutant strain Bacillus subtilis SH2 isolated from slaughter house soils of Warangal and improved through two-tier mutagenesis first by UV and then HNO2. Initially three efficient mutants with over production of alkaline protease were identified and among them only one stable mutant SHmIIIa was selected for further improvement through popular Response Surface Methodology of the FFCCD. Only X2 agitation, X6 KH2PO4 and interactive effects of X3*X3 inoculum, X4*X5 glucose and peptone have shown a significant improvement. The maximum alkaline protease production was achieved with the medium containing of X1 pH 9.8; X2 agitation 237.5 rpm; X3, inoculum size 4%; X4, glucose 6 g/L; X5, peptone 4g/L and X6, KH2PO4 2 g/L; under batch fermentative conditions with 33.33 fold increase
The dynamics and control of large flexible space structures-IV
The effects of solar radiation pressure as the main environmental disturbance torque were incorporated into the model of the rigid orbiting shallow shell and computer simulation results indicate that within the linear range the rigid modal amplitudes are excited in proportion to the area to mass ratio. The effect of higher order terms in the gravity-gradient torque expressions previously neglected was evaluated and found to be negligible for the size structures under consideration. A graph theory approach was employed for calculating the eigenvalues of a large flexible system by reducing the system (stiffness) matrix to lower ordered submatrices. The related reachability matrix and term rank concepts are used to verify controllability and can be more effective than the alternate numerical rank tests. Control laws were developed for the shape and orientation control of the orbiting flexible shallow shell and numerical results presented
The Secured Content-based Image Retrieval in Cloud Computing
Content-based image retrieval (CBIR) applications have been quickly evolved alongside the expansion in the amount, accessibility and significance of images in our day by day life. In any case, the wide organization of CBIR scheme has been restricted by its the serious calculation and capacity necessity. In this paper, we propose a protection safeguarding content-based image retrieval scheme, which permits the information proprietor to redistribute the image database and CBIR administration to the cloud, without uncovering the genuine content of the database to the cloud server. Neighborhood highlights are used to speak to the images, and earth mover's separation (EMD) is utilized to assess the closeness of images. The EMD calculation is basically a straight programming (LP) issue. The proposed scheme changes the EMD issue so that the cloud server can illuminate it without learning the delicate data. Likewise, nearby touchy hash (LSH) is used to improve the pursuit productivity. The security investigation and trials show the security and efficiency of the proposed scheme
Some three dimensional elasto-dynamic solutions of layered shells
Three dimensional solutions for natural frequencies and mode shapes of layered composite shells obtained by using the finite layer method, are presented in this paper. Higher order theories for laminated shells are discussed
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