Influence of La in xPBBiN of ternary nanoceramic composite (1-x)0.5PMN-0.5PZT-xPBBiN system by mechanic al activatio n technique for dielectric and piezoelectric properties

(1-x)[0.5Pb(Mg0.33Nb0.67)O3-0.5Pb(Zr0.53Ti0.47)O3]-x[Pb0.557Ba0.38La0.022Bi0.02Nb2O6] with both perovskite and tungsten bronze structured composite have been synthesized through mechanical activation technique. The strong influence of lanthanum addition to the lead-barium-bismuth-niobate (xPBLBiN) ceramics in perovskite structured (1-x)PMN-PZT on structural and functional properties is confirmed. X-ray diffraction patterns studies showed that these complex composites consisted of perovskite Cubic with tungsten bronze Orthorhombic phases. La modification in PBBiN of a ternary system (1-x)PMN-PZTxPBBiN revealed intensified orthorhombicity. As La increased the dielectric and piezoelectric properties tremendously increased in (1-x)PMN-PZT-xPBLBiN nanoceramic composite. The optimum dielectric and piezoelectric properties (εRT = 2931, kp = 0.461 and d33 = 428 pC/N) were found in x =0.4 composite. We achieved novel nanocomposites synthesized by high energy ball milling method and having binary structures in a single composite with excellent functional properties that can be used for energy harvesting applications

Fault-Tolerant Coherence Protocol for Distributed Shared Memory Systems

Distributed Shared Memory (DSM) systems are becoming increasingly more significant as a result of being used more extensively in modern computing environments. DSM gives the illusion of shared memory on a loosely couple system. In a scenario where systems are connected across a network, DSM coherence protocols should be able to scale well to larger networks. When real-time applications run on distributed systems, providing a high degree of reliability is an inherently error-prone environment is a formidable task. Regardless, fault tolerance, in terms of highly available data-access and uninterrupted service, should be provided. Recovery is the process of restoring a system to its normal operational state in the event of a failure. Reliability ensures the consistency of the data after recovery. Existing DSM systems provide reliability by replicating data, either in stable storage or in the main memories of different processors. But these systems suspend the DSM service during recovery. In time-critical applications, providing uninterrupted DSM service to the greatest possible extent is a necessity and a challenge. Research has been reported in the literature on architectures with a single server and multiple clients. This thesis reports on investigations on finding a solution where the server is not a single point of failure, faster recovery is possible in the event of a failure, and increased throughput can be obtained during normal operation of the system. It was found that better performance can be obtained by using the multi-server protocol when the user application exhibits locality of reference. The server was not a single point of failure and recovery form a single site failure was appoximately 50% faster when 2 servers, instead of 1, were used

Structural Characterization of Rapid Thermal Oxidized Si\u3csub\u3e1−x−y\u3c/sub\u3eGe\u3csub\u3ex\u3c/sub\u3eC\u3csub\u3ey\u3c/sub\u3e Alloy Films Grown by Rapid Thermal Chemical Vapor Deposition

The structural properties of as-grown and rapid thermal oxidized Si1−x−yGexCy epitaxial layers have been examined using a combination of infrared, x-ray photoelectron, x-ray diffraction, secondary ion mass spectroscopy, and Raman spectroscopy techniques. Carbon incorporation into the Si1−x−yGexCy system can lead to compressive or tensile strain in the film. The structural properties of the oxidized Si1−x−yGexCy film depend on the type of strain (i.e., carbon concentration) of the as-prepared film. For compressive or fully compensated films, the oxidation process drastically reduces the carbon content so that the oxidized films closely resemble to Si1−xGex films. For tensile films, two broad regions, one with carbon content higher and the other lower than that required for full strain compensation, coexist in the oxidized films

Investigation on dielectric and piezoelectric characterization of PLSZT-BT ceramics

In this paper, the ceramic compositions ($1-x$)Pb1−w−yLawSry(ZrzTi$_{1-z})_{(1-w/4)}$O3-xBaTiO3, where x = 0.15, 0.25, 0.35 and 0.45, fabricated through solid state reaction method were investigated for phase formation, microstructure, density, dielectric and piezoelectric properties. The combination of the two perovskite structured stoichiometric compositions (i.e., isovalent Sr2+ modified PLZT and BaTiO3) indicated that tetragonality enhanced further due to BaTiO3 concentration in PLSZT lattice. The BaTiO3 in PLSZT ceramics were homogeneously distributed within the two perovskite structured solid solutions. The dielectric characterization indicated that $\varepsilon _{RT}$ enhanced while $\tan\delta _{RT}$ and Tc decreased with increasing BT additions into PLSZT perovskite. The maximum $\varepsilon _{RT}$ = 2986 and $\varepsilon _{T_c}$ = 21468 were found in 0.55PLSZT-0.45BT ceramic system. The piezoelectric properties were influenced by both BaTiO3 and Sr2+ modified PLZT perovskite. The influence of BT modified PLSZT ceramics showed significant variations that has been discussed. The piezoelectric properties remarkably enhanced with maximum ($k_{p} = 0.541$ and $d_{33} = 518$ pC/N) values in the 0.55PLSZT-0.45BT composition and thus, could be a promising candidate among this series for possible capacitor, sensor and actuator applications

Microstructure, dielectric and ferroelectric characterization of Ba doped PLZT ceramics

Ba doped PLZT ceramic compositions with formula Pb0.982−zLa0.012Δ0.006Baz(Zr0.55Ti0.45)O3 for z = 0 to 6 mole% are synthesized by mixed-oxide method. Powder XRD studies indicate the coexistence of rhombohedral and tetragonal phase in 5 mole% Ba doped PLZT composition. SEM pictures show grain size control as Ba concentration increases in PLZT system. $\varepsilon_{rt}$ and tan δ are increased up to 4 mole% and 5 mole% Ba doped PLZT composition respectively. Dielectric maximum ($\varepsilon_{T_C}$) is decreased to 4 mole% Ba doped PLZT and Curie temperature (TC) is decreased with increase of Ba concentration in PLZT system. Coercive field (Ec) has shown gradual enhancement over series. Remanent (Pr) and spontaneous (Ps) polarizations are decreased to 5 mole% Ba doped PLZT composition

Dielectric, relaxor and ferroelectric characterization of La doped

The relaxor ferroelectric ceramics of La doped xPb(Mg1/3Nb2/3)O3-(1 − x)Pb(Zr0.55Ti0.45)O3 are synthesized by columbite precursor method. Powder X-ray diffraction patterns of these compositions indicate pseudocubic phase formation. Grain growth is inhibited with La doping and is increased with PMN concentration in PMN-PZT ceramics. $\varepsilon_{RT}$ and tan δ are increased to 1.5 mole% La doped PMN-PZT compositions while $\varepsilon_{T_C}$ and TC are decreased with La modification in PMN-PZT system. Pure and La modified 0.8PMN-0.2PZT compositions have shown the most promising relaxor behavior useful for multilayer capacitor (MLC) applications. The ferroelectric properties (Ec, Pr and Ps) are increased to 1.5 mole% La doped PMN-PZT composition. 77.84.Dy Niobates, titanates, tantalates, PZT ceramics, etc

Case Report - Localized cutaneous sporotrichosis lasting for 10 years

A case of localized cutaneous sporotrichosis lasting for 10 years is being reported. The fixed cutaneous variety creates diagnostic difficulty by mimicking other conditions, chiefly lupus vulgaris

Case Report - Localized cutaneous sporotrichosis lasting for 10 years

A case of localized cutaneous sporotrichosis lasting for 10 years is being reported. The fixed cutaneous variety creates diagnostic difficulty by mimicking other conditions, chiefly lupus vulgaris