A thermodynamic framework to develop rate-type models for fluids without instantaneous elasticity

In this paper, we apply the thermodynamic framework recently put into place by Rajagopal and co-workers, to develop rate-type models for viscoelastic fluids which do not possess instantaneous elasticity. To illustrate the capabilities of such models we make a specific choice for the specific Helmholtz potential and the rate of dissipation and consider the creep and stress relaxation response associated with the model. Given specific forms for the Helmholtz potential and the rate of dissipation, the rate of dissipation is maximized with the constraint that the difference between the stress power and the rate of change of Helmholtz potential is equal to the rate of dissipation and any other constraint that may be applicable such as incompressibility. We show that the model that is developed exhibits fluid-like characteristics and is incapable of instantaneous elastic response. It also includes Maxwell-like and Kelvin-Voigt-like viscoelastic materials (when certain material moduli take special values).Comment: 18 pages, 5 figure

Multiple template matching using the expansion filter

The paper describes a multiple-template generalization of a newly developed approach for template matching by signal expansion into a set of non-orthogonal template-similar basis functions. The single-template method is proven to be equivalent to "restoration" of undegraded images using the Wiener filter and optimizes a new and more practically defined matching quality criterion that the authors call discriminative signal-to-noise ratio (DSNR). Compared to the widely used matched filtering approach (also known as correlation matching) which is based an projection, expansion matching is based on decomposition and is shown to be more robust in conditions of noise, superposition and severe occlusion. In the paper, the authors extend the DSNR optimization approach to include more than one template. The generalized expansion filter presented is optimal in terms of DSNR and can be designed to elicit any desired response for each of the templates, while optimizing the DSNR criterion. The approach considers additive noise as a parameter and leads to a general formulation, of which many previous approaches (such as the synthetic discriminant function) form special cases. In the case of a single template, the formulation reverts to the previously mentioned Wiener restoration filter

Synthesis, characterization, antibacterial, antifungal and anthelmintic activities of a new 5-​nitroisatin Schiff base and its metal complexes

The copper (II)​, cobalt (II)​, nickel (II) and zinc (II) complexes of 5 - nitroisatin Schiff base (L) (L = Schiff base derived from 5-​nitroisatin and 2-​methyl-​4-​nitroaniline) were synthesized and characterized. The authenticity of the ligand and its metal complexes has been established by micro anal., IR, NMR, LC​/MS, UV-​VIS and elec. conductance measurements. The ligand acts as a bidentate agent in which the carbonyl oxygen and the azomethine nitrogen of 5-​nitroisatin are involved in co-​ordination. Square planar geometry was proposed for the Cu (II) and Ni (II) complexes and tetrahedral geometry was proposed for the Co (II) and Zn (II) complexes. The ligand and its metal complexes have been screened for antibacterial activity against Staphylococcus aureus, Escherichia coli, etc. and for antifungal activity against Aspergillus niger, Aspergillus flavous, etc. The Schiff base and its complexes were also screened for anthelmintic activity on earthworms. Both samples displayed significant activitie

Acute toxicity of metasystox to wedge clam, Donax cuneatus from west coast

96h acute toxicity tests were performed using commercial grade metasystox on the marine wedge clam, Donax cuneatus during summer 1985. The behaviour and mortality rates were recorded periodically. Most of the dams responded in opening the shell valves and extending the siphons quicker in low test concentrations (0.004-0.0052 p.p.m) but this was slow and late in high concentrations (0.0056-0.008 p.p.m). Mortality began to occur in 0.008 p.p.m. from 12 h, whereas, in 0.0052 p.p.m. from 60 h onwards. The observed LC sub(0) value was 0.004 p.p.m. and LC sub(50) 0.0064 p.p.m. The regression equation established was Y = 79.0891 + 33.4523 X. The rate of oxygen concentration increased at LC sub(0) and LC sub(50) values compared to control indicating the disturbed physiological adjustment. The results are correlated with physico-chemical parameters of seawater and discussed in the light of pesticide toxicity to the dam

Synthesis And Characterization Of Co-Doped SnO2/TiO2 Semiconductor Nano Crystallites Via Sol-Gel Method

SnO2/TiO2 nano particles are novel wide band gap semiconductors with modified applications of SnO2 and TiO2 in some fields including gas sensing, photo catalytic, solar cells and so on. The Co-doped SnO2/TiO2 nano particles were obtained via sol-gel method with different amounts of doping material as 2.5 %, 6 % and 10 mol %. The crystallite sizes of resulting material were from 3.8 nm for 0.1 wt % Co-doped SnO2/TiO2 to 19.1 nm for un-doped. Morphology and nanostructure of the crystalline SnO2/TiO2 nano particles were characterized by means of X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), Thermal gravimetric analysis (TGA), field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDX). It has been shown that fine semiconductor nano structures were formed. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/933

A Simple Sol Gel Protocol Towards Synthesis Of Semiconducting Oxide Nanomaterial

Nanostructured Tin oxide (SnO2), powders was synthesized by employing a novel Sol-gel protocol at RT. A wide variety of techniques such as energy – dispersive spectroscopy(EDX), N2 sorption, X-ray diffraction (XRD), have been used to study the formation process and characterization of the nanoparticles obtained. Transmission electron microscopy (TEM) has been applied to find out about the shape and size distribution of the particles. The nanoparticles thus synthesized were monodispersed, with an average particle size of ~ 10 nm and spherical in shape. The EDX analysis revealed the presence of Sn, O signal in the synthesized nanoparticles confirming the purity of the synthesized samples. This protocol appears promising for application in large-scale synthesis of nanoparticles. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/933

Effect of Hetrovalent substitution at Mn site on the Magnetic and Transport Properties of La0.67_{0.67}Sr0.33_{0.33}MnO3_3

Magnetic and transport properties of Ti substituted La$_{0.67}$Sr$_{0.33}$MnO$_3$ are drastically affected with a change in preparation conditions. Low temperature infra-red absorption measurements reveal that this is perhaps due to inhomogeniety in substitution of Ti$^{4+}$ on Mn sites. It is found that, in the high temperature annealed samples, the substitution of Ti supresses the double exchange interaction due to the formation of Mn$^{3+}$-O-Ti$^{4+}$ chains. While in the low temperature annealed case substitution of Ti causes formation of isolated ferromagnetic clusters linked to each other by a variable range hopping polaron.Comment: 11 pages, 8 figures, accepted in J. Magn. Magn. Magn. Mate

Effects of Velocity-slip and Viscosity Variation for Lubrication of Roller Bearings

A generalised form of Reynolds equation for two symmetrical surfaces is derived considering velocity-slip at the bearing surfaces. This equation is applied to study the effects ofvelocity -slip for the lubrication of roller bearings under lightly loaded conditions. Expressions for the point of cavitation, load capacities, and coefficient of friction obtained are also studied theoretically for various parameters

Motivational Social Visualizations for Personalized E-Learning

A large number of educational resources is now available on the Web to support both regular classroom learning and online learning. However, the abundance of available content produces at least two problems: how to help students find the most appropriate resources, and how to engage them into using these resources and benefiting from them. Personalized and social learning have been suggested as potential methods for addressing these problems. Our work presented in this paper attempts to combine the ideas of personalized and social learning. We introduce Progressor + , an innovative Web-based interface that helps students find the most relevant resources in a large collection of self-assessment questions and programming examples. We also present the results of a classroom study of the Progressor +  in an undergraduate class. The data revealed the motivational impact of the personalized social guidance provided by the system in the target context. The interface encouraged students to explore more educational resources and motivated them to do some work ahead of the course schedule. The increase in diversity of explored content resulted in improving students’ problem solving success. A deeper analysis of the social guidance mechanism revealed that it is based on the leading behavior of the strong students, who discovered the most relevant resources and created trails for weaker students to follow. The study results also demonstrate that students were more engaged with the system: they spent more time in working with self-assessment questions and annotated examples, attempted more questions, and achieved higher success rates in answering them