Measurement of transverse vibrations/visualization of mode shapes in square plate by using digital speckle pattern interferometry and wavelet transform

New filtering scheme is investigated and implemented on digital speckle pattern interferometric fringes to enhance the signal-to-noise ratio (SNR) in the speckle interferograms. To establish the potential of new filtering scheme the experiment was conducted on the vibrating cantilever beam. Experimental results revealed that the new filtering scheme is more powerful than other known filtering schemes (Kumar et al. Opt Laser Eng 2004;41:81–93. Kumar et al. Opt Laser Technol 2001;33:567–571. Shakher et al. Opt Eng 2002;41:176–180. Shakher et al. Proceedings ICICS, Singapore, 9–12 September 1997, p. 953–956. Bowler et al. Proceedings of IEE second international conference on image processing, London, 1986, p. 24–26. Lim. Opt Eng 1981;20:670–678. Devila et al. J Mod Opt 1995;42:1795–1804; Kaufmann et al. Opt Eng 1996;35:9–14). The new scheme reduced the speckle noise and improved SNR in speckle interferograms. Further, the new investigated filtering scheme is implemented to study the mode shapes of square plates under two different boundary conditions. In the first condition all the edges of the square plate were fixed while in the second condition two adjacent edges were fixed and the remaining two edges were free. From the experimental results it is clear that the mode shapes are more distinctly visible with the implementation of the new filtering scheme as compared to other known schemes. Under both the boundary conditions the recorded resonance frequencies were compared with the calculated values of resonance frequencies based on classical theory. The results obtained form DSPI show good agreement with classical theory.     

Solid‐state 13C and 129Xe NMR study of poly(vinyl alcohol) and poly(vinyl alcohol)/lactosilated chitosan gels

Dry and hydrated poly(vinyl alcohol) (PVA) gels with 55% (a‐PVA) and 61% (s‐PVA) syndiotacticity and related PVA/lactyl chitosan (LC) blends have been investigated with ¹²⁹Xe and cross‐polarization/magic‐angle‐spinning ¹³C NMR techniques. Although the dry gels exhibit two broad ¹²⁹Xe resonances in the slow‐to‐intermediate exchange limit, both hydrated gels show three resonances. The corresponding dry blends exhibit two signals, the chemical shifts and line widths of which change with respect to those of pure PVA, whereas one (a‐PVA/LC) or two (s‐PVA/LC) signals appear in the spectra of the hydrated blends. A comparative analysis of the data demonstrates that LC rearranges the domains of the polymeric matrix in both the dry and hydrated blends according to the syndiotacticity of the PVA chains. Information on the molecular motions of the amorphous and swollen polymeric domains in the kilohertz range has been obtained from an analysis of the spin‐lattice relaxation times. These data indicate that the dynamics and arrangement of the PVA chains in the gels are strongly affected by their tacticity and the addition of the copolymer LC. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3123–3131, 2003     

The influence of thiourea on the electroreduction of Zn2+ ions in various supporting electrolytes in respect to the cap-pair effect

The mechanism of the cap-pair effect was examined with respect to its acceleration of the electro-reduction of Zn²⁺ ions in NaCIO₄, NaCl and NaBr. It was found that the presence of thiourea in the solution increased the rate of the electrode process; a role is played in the acceleration by the composition of zinc complexes formed in the bulk of the solution.     

Nucleophilic substitutions of α-halo-ketones-XXIIAcetolysis of α' - phenoxy - α - chloro - ketones. A comparison of their reactivity with that of the corresponding thioethers

The results obtained in the acetolysis of α - chloro - ketones 1a-e are compared with those previously reported for the acetolysis of the corresponding α' - phenylthio-α - chloro - ketones 15a-e and discussed in terms of the enolization-solvolysis mechanisms (Schemes 1 and 2).     

New concepts in neutrosophic graphs with application

A neutrosophic set is a generalization of an intuitionistic fuzzy set. Neutrosophic models give more flexibility, precisions and compatibility to the system as compared to intuitionistic fuzzy models. In this research study, we apply the concept of neutrosophic sets to graphs and discuss certain concepts of single-valued neutrosophic graphs. We illustrate the concepts by several examples. We investigate some interesting properties. We describe an application of single-valued neutrosophic graph in decision making process. We also present the procedure of our proposed method as an algorithm.     

Some Exact Relativistic Models of Electrically Charged Self-bound Stars

In continuation of recent work done by the present authors (Int. J. Theor. Phys. 2013, doi:10.1007/s10773-013-1538-y, hereafter paper I) some new exact families of static spherically symmetric perfect fluid solution of Einstein–Maxwell gravitational field equations are presented. These solutions and the corresponding equations of state, presented in parametric form, may be astrophysically significant in constructing relativistic stellar models of electrically charged self-bound stars.     

High Pressure High Temperature Dynamic Rheometry of Sulfonated Polyacrylamide Solutions in Electrolyte Media as Used for Oil Recovery Applications

Sulfonated polyacrylamide (SPAA) solutions were prepared and the effects of pressure, polymer concentration, and water temperature, pH and salinity on their rheological behavior were investigated using a concentric cylinder dynamic rheometer equipped with a high pressure cell. According to the rheological flow curves the shear stress of SPAA solutions increased less than in proportion to their shear rates; that is, a shear thinning effect occurred. For polymer solutions containing 15,000 ppm of SPAA, shear viscosity, and stress were nearly insensitive to pressure. However, the shear viscosity and stress of SPAA solutions were affected by temperature and this effect was more evident at lower pressure. The flow curves indicated the shear viscosity and stress of the samples increased with increasing SPAA concentration and pH of the water, but were decreased with increasing water salinity and temperature.     

P‐Dodecylbenzenesulfonic Acid: A Highly Efficient Catalyst for One‐Pot Synthesis of α‐Aminophosphonates in Aqueous Media

A highly efficient one‐pot three‐component reaction of aldehydes or ketones, amines, and trimethyl or triethyl phosphite catalyzed by p‐dodecylbenzensulfonic acid is developed for the synthesis of α‐aminophosphonates at room temperature in water. © 2013 Wiley Periodicals, Inc. Heteroatom Chem 24:174–178, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21079     

Dual fast projected gradient method for quadratic programming

The application of the fast gradient method to the dual quadratic programming (QP) problem leads to the dual fast projected gradient (DFPG) method. The DFPG converges with O(k ^?2) rate, where k > 0 is the number of steps. At each step, it requires O(nm) operations. Therefore for a given ${\varepsilon > 0}$ an ${\varepsilon}$ -approximation to the optimal dual function value one achieves in ${O(nm\varepsilon^{-\frac{1}{2}})}$ operations. We present numerical results which strongly corroborate the theory. In particular, we demonstrate high efficiency of the DFPG for large scale QP.