Electromechanical and Dynamic Characterization of In-House-Fabricated Amplified Piezo Actuator

A diamond-shaped amplified piezo actuator (APA) fabricated using six multilayered piezo stacks with maximum displacement of 173 μm at 175V and the amplification factor of 4.3. The dynamic characterization of the actuator was carried out at different frequencies (100 Hz–1 kHz) and at different AC voltages (20V–40V). The actuator response over this frequency range was found neat, without attenuation of the signal. Numerical modeling of multilayered stack actuator was carried out using empirical equations, and the electromechanical analysis was carried out using ABAQUS software. The block force of the APA was 81 N, calculated by electromechanical analysis. This is similar to that calculated by dynamic characterization method

On the low energy properies of fermions with singular interactions

We calculate the fermion Green function and particle-hole susceptibilities for a degenerate two-dimensional fermion system with a singular gauge interaction. We show that this is a strong coupling problem, with no small parameter other than the fermion spin degeneracy, N. We consider two interactions, one arising in the context of the $t-J$ model and the other in the theory of half-filled Landau level. For the fermion self energy we show in contrast to previous claims that the qualitative behavior found in the leading order of perturbation theory is preserved to all orders in the interaction. The susceptibility $\chi_Q$ at a general wavevector $\bf{Q} \neq 2\bf{p_F}$ retains the fermi-liquid form. However the $2p_F$ susceptibility $\chi_{2p_F}$ either diverges as $T -> 0$ or remains finite but with nonanalytic wavevector, frequency and temperature dependence. We express our results in the language of recently discussed scaling theories, give the fixed-point action, and show that at this fixed point the fermion-gauge-field interaction is marginal in $d=2$, but irrelevant at low energies in $d \ge 2$.Comment: 21 pages, uuencoded LATEX file with included Postscript figures, R

A Novel Automated Technique for Ferrous Materials Classification

The composition of the material and its processing conditions effect the microstructure of that material. Mechanical properties are inturn dependent on the material\u27s microstructure. Thus the study of microstructure is important to asses the material processing conditions. This also helps in forensic analysis of material failure. Metallography deals with the material microstructure study. Classification of Material is the first step of the metallographic analysis. The tonal distribution of the microstructural image is completly dependent on the material and its composition. The current paper proposes a automated technique for classification of materials using image processing algorithms

Evaluation of anti-ulcer activity of 4-hydrooxy benzalydehide against NSAIDs induced ulcers in rats

Background: The aim of this study was to evaluate antiulcer activity of 4-hydroxybenzaldehyde against NSAIDs induced ulcer in rats based differences in its morphology, distance with other external landmarks and also to sigmoid and transverse sinuses.Methods: The antiulcer activity of 4-HBD was evaluated using pylorus ligation-aspirin induced ulcer method. Animals of this models were treated with 4-HBD (50mg/kg, 100mg/kg and 150mg/kg).Results: It has been observed that 4-HBD at low dose (50mg/kg), intermediate dose (100mg/kg) and high dose (150mg/kg) showed significant increase in pH, significant decrease in gastric volume, significant decrease in ulcer index and significant decrease in total acidity.Conclusions: The impact of 4-HBD therapy with intermediate (100mg/kg, p.o.) dose was observed to be similar with the positive control group. 

“EVALUATION OF GALPHIMIA GLAUCA STEM METHANOL EXTRACT FRACTIONS FOR ANALGESIC AND ANTI-INFLAMMATORY ACTIVITIES”

Objective: This current investigation assesses in vivo central and peripheral analgesic effects and anti-inflammatory properties of fractions obtained from Galphimia glauca (GG) stem methanol extract. Methods: The laboratory models such as Swiss albino mice and Wistar albino rats were employed in the studies. The GG stem methanol extract was subjected to fractionation with solvents such as hexane, chloroform, ethyl acetate, and methanol. Orally, the dose range of 100, 200, and 400 mg/kg was given for 1 day for evaluating analgesic (hotplate test, tail clip test, writhing test, and formalin test) and weekdays for assessing anti-inflammatory activity (carrageenan and cotton pellet test methods), respectively. The experimental studies were further conducted for determining the involvement of central and peripheral receptor actions in the analgesic activity of the extract by prechallenging it with naloxone and acetic acid, respectively. The in vivo anti-inflammatory studies were conducted using carrageenan-induced rat paw edema model and cotton pellet granuloma test. Results: The LD50 of the extract was found to be >2000 mg/kg b.w. The methanol fraction of 400 mg/kg dose exhibited significant (p≤0.001) and dose-dependent analgesic and anti-inflammatory activity. It also exhibited central and peripheral analgesic actions when treated with naloxone and acetic acid, respectively. Conclusion: The results revealed that the stem methanol fraction has more potential in terms of analgesic and anti-inflammatory properties

The half-filled Landau level - composite fermions and dipoles

The composite-fermion approach as formulated in the fermion Chern-Simons theory has been very successful in describing the physics of the lowest Landau level near Landau level filling factor 1/2. Recent work has emphasized the fact that the true quasiparticles at these filling factors are electrically neutral and carry an electric dipole moment. In a previous work, we discussed at length two formulations in terms of dipolar quasiparticles. Here we briefly review one approach - termed electron-centered quasiparticles - and show how it can be extended from 1/2 to nearby filling factors where the quasiparticles carry both an electric dipole moment and an overall charge.Comment: 10 pages, minor improvements of notation and referencin

Integrable field theory and critical phenomena. The Ising model in a magnetic field

The two-dimensional Ising model is the simplest model of statistical mechanics exhibiting a second order phase transition. While in absence of magnetic field it is known to be solvable on the lattice since Onsager's work of the forties, exact results for the magnetic case have been missing until the late eighties, when A.Zamolodchikov solved the model in a field at the critical temperature, directly in the scaling limit, within the framework of integrable quantum field theory. In this article we review this field theoretical approach to the Ising universality class, with particular attention to the results obtained starting from Zamolodchikov's scattering solution and to their comparison with the numerical estimates on the lattice. The topics discussed include scattering theory, form factors, correlation functions, universal amplitude ratios and perturbations around integrable directions. Although we restrict our discussion to the Ising model, the emphasis is on the general methods of integrable quantum field theory which can be used in the study of all universality classes of critical behaviour in two dimensions.Comment: 42 pages; invited review article for J. Phys.

Integer Complexity: Breaking the Θ(n 2 ) barrier

Abstract-The integer complexity of a positive integer n, denoted f (n), is defined as the least number of 1's required to represent n, using only 1's, the addition and multiplication operators, and the parentheses. The running time of the algorithm currently used to compute f (n) is Θ(n 2 ). In this paper we present an algorithm with Θ(n log 2 3 ) as its running time. We also present a proof of the theorem: the largest solutions of f (m) = 3k, 3k±1 are, respectively, m = 3 k , 3 k ± 3 k−1