Dynamics and control of buckling type devices using SMA wire integrated beam

An analysis and design study using Shape Memory Alloy (SMA) wire integrated beam and its buckling shape control are reported. The dynamical system performance is analyzed with a mathematical set-up involving nonlocal and rate sensitive kinetics of phase transformation in the SMA wire. A standard phenomenological constitutive model reported by Brinson (1993) is modified by considering certain consistency conditions in the material property tensors and by eliminating spurious singularity. Considering the inhomogeneity effects, a finite element model of the SMA wire is developed. Simulations are carried out to study the buckling shape control of a beam integrated with SMA wire.

Constructing commutative semifields of square order

The projection construction has been used to construct semifields of odd characteristic using a field and a twisted semifield [Commutative semi-fields from projection mappings, Designs, Codes and Cryptography, 61 (2011), 187{196]. We generalize this idea to a projection construction using two twisted semifields to construct semifields of odd characteristic. Planar functions and semifields have a strong connection so this also constructs new planar functions.

Experimental Demonstration of H{infty} Control based Active Vibration Suppression in Composite Fin-tip of Aircraft using Optimally Placed Piezoelectric Patch Actuators

The goal of this study is the multi-mode structural vibration control in the composite fin-tip of an aircraft. Structural model of the composite fin-tip with surface bonded piezoelectric actuators is developed using the finite element method. The finite element model is updated experimentally to reflect the natural frequencies and mode shapes accurately. A model order reduction technique is employed for reducing the finite element structural matrices before developing the controller. Particle swarm based evolutionary optimization technique is used for optimal placement of piezoelectric patch actuators and accelerometer sensors to suppress vibration. H{infty} based active vibration controllers are designed directly in the discrete domain and implemented using dSpace® (DS-1005) electronic signal processing boards. Significant vibration suppression in the multiple bending modes of interest is experimentally demonstrated for sinusoidal and band limited white noise forcing functions.

3-Benzyl-6-benzylamino-1-methyl-5-nitro-1,2,3,4-tetrahydropyrimidine

In the title compound, C19H22N4O2, the tetrahydropyrimidine ring adopts an envelope conformation (with the N atom connected to the benzyl group representing the flap). This benzyl group occupies a quasi-axial position. The two benzyl groups lie over the tetrahydropyridimidine ring. The amino group is a hydrogen-bond donor to the nitro group.

Organometallic chemistry of diphosphazanes. Part 26. Ruthenium hydride complexes of chiral and achiral diphosphazane ligands and asymmetric transfer hydrogenation reactions

The half-sandwhich ruthenium chloro complexes bearing chelated diphosphazane ligands, [(eta(5)-Cp)RuCl{kappa(2)-P,P-(RO)(2)PN(Me)P(OR)(2)}] [R = C6H3Me2-2,6] (1) and [(eta(5)-Cp*)RuCl{kappa(2)-P, P-X2PN(R)PYY'}] [R = Me, X = Y = Y' = OC6H5 (2); R = CHMe2, X-2 = C20H12O2, Y = Y' = OC6H5 (3) or OC6H4'Bu-4 (4)] have been prepared by the reaction of CpRu(PPh3)(2)Cl with (RO)(2)PN(Me)P(OR)(2) [R = C6H3Me2-2,6 (L-1)] or by the reaction of [Cp*RuCl2](n) with X2PN(R)PYY' in the presence of zinc dust. Among the four diastereomers (two enantiomeric pairs) possible for the "chiral at metal" complexes 3 and 4, only two diastereomers (one enantiomeric pair) are formed in these reactions. The complexes 1, 2, 4 and [(eta(5)-Cp)RuCl {kappa(2)-P,P-Ph2PN((S)-*CHMePh)PPhY)] [Y = Ph (5) or N2C3HMe2-3,5 (SCSPRRu)-(6)] react with NaOMe to give the corresponding hydride complexes [(eta(5) -Cp)RuH {kappa(2)-P,P-(RO)(2)PN(Me)P(OR)(2)}] (7), [(eta(5)-Cp*)RuH {kappa(2)-P,P'-X2PN(R)PY2)] [R = Me, X = Y = OC6H5 (8); R = CHMe2, X-2 = C20H12O2, Y = OC6H4'Bu-4 (9)] and [(eta(5) -Cp)RuH(kappa(2)-P, P-Ph2PN((S)-*CHMePh)PPhY)][Y =Ph (10) or N2C3HMe2-3,5 (SCSPRRu)(11a) and (SCSPSRu)-(11b)]. Only one enantiomeric pair of the hydride 9 is obtained from the chloro precursor 4 that bears sterically bulky substituents at the phosphorus centers. On the other hand, the optically pure trichiral complex 6 that bears sterically less bulky substituents at the phosphorus gives a mixture of two diastereomers (11a and 11b). Protonation of complex 7 using different acids (HX) gives a mixture of [(eta(5)- Cp)Ru(eta(2)-H-2){kappa(2)-P, P-(RO)(2)PN(Me)P(OR)(2))]X (12a) and [(eta(5)-Cp)Ru(H)(2){kappa(2)-P, P-(RO)(2)PN(Me)P(OR)(2)}]X (12b) of which 12a is the major product independent of the acid used; the dihydrogen nature of 12a is established by T, measurements and also by synthesizing the deuteride analogue 7-D followed by protonation to obtain the D-H isotopomer. Preliminary investigations on asymmetric transfer hydrogenation of 2-acetonaphthone in the presence of a series of chiral diphosphazane ligands show that diphosphazanes in which the phosphorus centers are strong pi-acceptor in character and bear sterically bulky substituents impart moderate levels of enantioselectivity. Attempts to identify the hydride intermediate involved in the asymmetric transfer hydrogenation by a model reaction suggests that a complex of the type, [Ru(H)(Cl){kappa(2)-P,P-X2PN(R)PY2)(solvent)(2)] could be the active species in this transformation. (c) 2007 Elsevier B.V. All rights reserved.

Study on Young's modulus and microhardness of carbon nanotubes reinforced copper nanocomposite

Carbon nanotubes (CNTs) were discovered by Iijima in 1991 as the fourth form of carbon. Carbon nanotubes are the ultimate form of the carbon fibre because of its high Young's modulus in the order of 1 TPa, which is very useful for load transfer in nanocomposites. In the present work, CNT/Cu nanocomposites were fabricated by the powder metallurgy technique, and after extrusion of the nanocomposites, bright field transmission electron microscopic studies were carried out. From the transmission electron microscopic images obtained, a novel method of ascertaining the Young's modulus of multiwalled CNTs is worked out in the present paper, which turns out to be 0.94 TPa, which is consistent with experimental results. Furthermore, an attempt is made to investigate the microhardness of copper by reinforcing it with multiwalled CNTs. There is an increase in hardness by twofold in CNT/Cu nanocomposites as compared to pure Cu matrix. This is due to high relative density, even distribution of CNTs and proper bonding at CNT/Cu interfaces.

Leuconostoc spoilage of refrigerated, packaged foods

Leuconostoc spp. are lactic acid bacteria (LAB) implicated in food spoilage, especially on refrigerated, modified atmosphere packaged (MAP) meats. The overall aim of this thesis was to learn more about Leuconostoc spp. as food spoilage organisms with a focus on commercial products where LAB spoilage is considered a problem and the main factor limiting shelf-life. Therefore, we aimed to identify Leuconostoc spp. involved in food spoilage, as well as to characterise the spoilage reactions they caused and their contamination sources during poultry meat processing. In addition, we examined the distribution of strains of Leuconostoc gasicomitatum in different food commodities. Finally, we analysed the genome content of L. gasicomitatum LMG 18811 with a special focus on metabolic pathways related to food spoilage. The findings show that Leuconostoc gelidum and L.gasicomitatum were responsible for the discoloration and off-odours developed in beef steaks. Together with Leuconostoc mesenteroides, these Leuconostoc spp., also cause spoilage of vegetable sausages. In contrast, we showed that Leuconostoc spp. are not important for the shelf-life or quality of non-marinated broiler products although, in marinated broiler fillet products, Leuconostoc spp., L.gasicomitatum in particular, are considered spoilage organisms. Furthermore, the findings of the contamination survey we carried out in a poultry processing plant indicated that spoilage Leuconostoc spp. are derived from the processing environment rather than from the broilers, and that air movement distributes psychrotrophic spoilage LAB, including leuconostocs, and has an important role in meat contamination during poultry processing. Pulsed-field gel electrophoresis (PFGE) based genotyping of L. gasicomitatum strains demonstrated that certain genotypes are common in various meat products. In contrast, genotypes associated with meat were not recovered in vegetable-based sources. This suggests that these two food categories either become contaminated with, or favour the growth of different genotypes. Furthermore, the results indicated that the meat processing environment contributes to L. gasicomitatum contamination as certain genotypes were repeatedly identified from products of the same processing plant. Finally, the sequenced and annotated genome of L.gasicomitatum LMG 18811 allowed us to identify the metabolic pathways and reactions resulting in food spoilage.

ErbB-2 expression and its association with other biological parameters of breast cancer among Indian women

Overexpression of the epidermal growth factor receptor family genes, which include ErbB-1, 2, 3 and 4, has been implicated in a number of cancers. We have studied the extent of ErbB-2 overexpression among Indian women with sporadic breast cancer. Methods: Immmunohistochemistry and genomic polymerase chain reaction (PCR) were used to study the ErbB2 overexpression. ErbB2 status was correlated with other clinico-pathological parameters, including patient survival. Results: ErbB-2 overexpression was detected in 43.2% (159/368) of the cases by immunohistochemistry. For a sub-set of patients (n = 55) for whom total DNA was available, ErbB-2 gene amplification was detected in 25.5% (14/55) of the cases by genomic PCR. While the ErbB2 overexpression was significantly higher in patients with lymphnode (χ2 = 12.06, P≤ 0.001), larger tumor size (χ2 = 8.22, P = 0.042) and ductal carcinoma (χ2 = 15.42, P ≤ 0.001), it was lower in patients with disease-free survival (χ2 = 22.13, P ≤ 0.001). Survival analysis on a sub-set of patients for whom survival data were available (n = 179) revealed that ErbB-2 status (χ2 =25.94, P ≤ 0.001), lymphnode status (χ2 = 12.68, P ≤ 0.001), distant metastasis (χ2 = 19.49, P ≤ 0.001) and stage of the disease (χ2 = 28.04, P ≤0.001) were markers of poor prognosis. Conclusions: ErbB-2 overexpression was significantly greater compared with the Western literature, but comparable to other Indian studies. Significant correlation was found between ErbB-2 status and lymphnode status, tumor size and ductal carcinoma. ErbB-2 status, lymph node status, distant metastasis and stage of the disease were found to be prognostic indicators.

Electroreduction of oxygen on some novel cobalt phthalocyanine complexes

The catalytic activity of cobalt phthalocyanine monomer and some of its polymeric derivatives towards the electroreduction of molecular oxygen in salt and alkaline solutions is examined. It is found that most of these complexes exhibit a higher catalytic activity than the cobalt phthalocyanine monomer.

A generalized Linear Programming based approach to optimal divisible load scheduling

In this paper we propose a general Linear Programming (LP) based formulation and solution methodology for obtaining optimal solution to the load distribution problem in divisible load scheduling. We exploit the power of the versatile LP formulation to propose algorithms that yield exact solutions to several very general load distribution problems for which either no solutions or only heuristic solutions were available. We consider both star (single-level tree) networks and linear daisy chain networks, having processors equipped with front-ends, that form the generic models for several important network topologies. We consider arbitrary processing node availability or release times and general models for communication delays and computation time that account for constant overheads such as start up times in communication and computation. The optimality of the LP based algorithms is proved rigorously.

Explicit Construction of Optimal Exact Regenerating Codes for Distributed Storage

Erasure coding techniques are used to increase the reliability of distributed storage systems while minimizing storage overhead. Also of interest is minimization of the bandwidth required to repair the system following a node failure. In a recent paper, Wu et al. characterize the tradeoff between the repair bandwidth and the amount of data stored per node. They also prove the existence of regenerating codes that achieve this tradeoff. In this paper, we introduce Exact Regenerating Codes, which are regenerating codes possessing the additional property of being able to duplicate the data stored at a failed node. Such codes require low processing and communication overheads, making the system practical and easy to maintain. Explicit construction of exact regenerating codes is provided for the minimum bandwidth point on the storage-repair bandwidth tradeoff, relevant to distributed-mail-server applications. A sub-space based approach is provided and shown to yield necessary and sufficient conditions on a linear code to possess the exact regeneration property as well as prove the uniqueness of our construction. Also included in the paper, is an explicit construction of regenerating codes for the minimum storage point for parameters relevant to storage in peer-to-peer systems. This construction supports a variable number of nodes and can handle multiple, simultaneous node failures. All constructions given in the paper are of low complexity, requiring low field size in particular.

Oxide-based bifunctional oxygen electrode for rechargeable metal/air batteries

Statistical methods for optimizing the morphology of oxide-based, bifunctional oxygen electrodes for use in rechargeable metal/air batteries are examined with regard to binder composition, compaction time, and compaction load. Results show that LaNiO3 with PTFE binder in a nickel mesh envelope provides a satisfactory electrode.

Characterization of a mercury-reducing Bacillus cereus strain isolated from the Pulicat Lake sediments, south east coast of India

Pulicat Lake sediments are often severely polluted with the toxic heavy metal mercury. Several mercury-resistant strains of Bacillus species were isolated from the sediments and all the isolates exhibited broad spectrum resistance (resistance to both organic and inorganic mercuric compounds). Plasmid curing assay showed that all the isolated Bacillus strains carry chromosomally borne mercury resistance. Polymerase chain reaction and southern hybridization analyses using merA and merB3 gene primers/probes showed that five of the isolated Bacillus strains carry sequences similar to known merA and merB3 genes. Results of multiple sequence alignment revealed 99% similarity with merA and merB3 of TnMERI1 (class II transposons). Other mercury resistant Bacillus species lacking homology to these genes were not able to volatilize mercuric chloride, indicating the presence of other modes of resistance to mercuric compounds.