(PEG) x NH4ClO4: a new polymeric fast proton conductor

A new polymer electrolyte (PEG) _x NH₄ClO₄(x = 5, 10, 15, 20) has been prepared that shows protonic conduction. The room temperature conductivities are of the order of 10⁻⁷S/cm, and increase with decrease in salt concentration. NMR line width studies indicate fairly low glass transition temperatures of the polymer salt complexes. Paper presented at the poster session of MRSI AGM VI. Kharagpur, 1995     

Pulsed laser deposition of indium antimonide

Single crystalline oriented films of indium antimonide have been grown on cadmium telluride substrates by the pulsed laser deposition technique. The films were (111) oriented which is the substrate orientation. The composition of the grown films were found to deviate from that of the target owing to loss of antimony during evaporation. This deviation from stoichiometry led to film-substrate reaction, resulting in mixed interface. The antimony deficiency in the films were controlled by correcting the stoichiometry, which led to avoiding mixed interfaces. The stoichiometric films showed good surface morphology and well defined sharp interfaces. The IR transmission spectrum showed sharp band to band absorption and effective detection in the MWIR. Paper presented at the poster session of MRSI AGM VI, Kharagpur, 1995     

Reliability models for computer systems: An overview including dataflow graphs

The reliability of a system is the probability that the system will perform its intended mission under given conditions. This paper provides an overview of the approaches to reliability modelling and identifies their strengths and weaknesses. The models discussed include structure models, simple stochastic models and decomposable stochastic models. Ignoring time-dependence, structure models give reliability as a function of the topological structure of the system. Simple stochastic models make direct use of the properties of underlying stochastic processes, while decomposable models consider more complex systems and analyse them through subsystems. Petri nets and dataflow graphs facilitate the analysis of complex systems by providing a convenient framework for reliability analysis.     

Low sintering effect on structural,electrical and magnetic properties of rare-earth metal ion Er3+-substituted nickel–zinc spinal ferrites

Journal of Materials Science: Materials in Electronics - The nano-crystalline particles of erbium-substituted Ni–Zn ferrites with compositional formula Ni0.7Zn0.3ErxFe2?xO4...     

The mechanism of adhesion and printability of plasma processed PET films

Of the several techniques available for the surface modification, plasma processing has proved to be very appropriate. The low temperature plasma is a soft radiation source and it affects the material only over a few hundred Å deep, the bulk properties remaining unaffected. Plasma surface treatment also offers the advantage of greater chemical flexibility. PET films are widely used for packaging and electrical insulation. The studies of adhesion and printability properties are important. In the present study PET films are treated in air plasma for different time of treatment. The improvement in adhesion is studied by measuring T-peel and Lap shear strength. In addition, printability of plasma treated PET films is studied by cross test method. It has been found that printability increases considerably for plasma treatment of short duration. Therefore it is interesting to study the surface composition and morphology by contact angle measurement, ESCA and AFM. Surface energy and surface roughness can be directly correlated to the improvement in above-mentioned surface related properties. It has been found that the surface oxidation occurs containing polar functional groups such as C-O, COO. A correlation of all such observations from different techniques gives a comprehensive picture of the structure and surface composition of plasma treated PET films.     

Effect of misch metal inoculation on microstructure, mechanical and wear properties of hypoeutectic gray cast irons

Alloyed gray cast irons were made with and without misch metal inoculation (0.1%). The mechanical and wear properties were compared with conventional gray cast iron used for a typical clutch application in heavy commercial vehicles. Alloyed gray iron without misch metal showed higher volume fraction of pearlite (89%) and lower flake graphite (11%). Misch metal inoculated gray irons showed higher volume of flake graphite (15%) with 85% pearlite as matrix. Alloyed gray irons produced tensile strength from 300 to 344 MPa and hardness in the range of 221–247 VHN. Misch metal inoculation has slightly increased the graphite volume (40–60%) with corresponding decrease in strength and hardness (9–13%) in alloyed gray irons. The specific wear rates of all alloyed gray irons are significantly lower (<34%) compared to unalloyed base at two different sliding speeds (1.6 m/s and 2.5 m/s). The friction coefficient is less than 0.4 for alloyed gray irons as against 0.5–0.7 for unalloyed base gray iron at both the sliding speeds. This is attributed to the presence of alloying additives within the matrix which resists adhesive and abrasive wear loss. Among the inoculated alloyed gray irons, the alloy with lower S content (0.08%) showed higher wear rate at higher sliding speed due to lower graphite flake density compared to higher S containing iron (0.12%). This indicates that the wear rate is influenced by the amount of graphite which is released into the interface during sliding to provide lubrication and reduce wear. Inoculation with rare earth misch metal has a positive influence over graphite morphology in gray iron.     

Microstructure, crystallinity, and properties of low-pressure MOCVD-grown europium oxide films

A study of growth, structure, and properties of Eu₂O₃ thin films were carried out. Films were grown at 500–600 °C temperature range on Si(1 0 0) and fused quartz from the complex of Eu(acac)₃·Phen by low pressure metalorganic chemical vapor deposition technique which has been rarely used for Eu₂O₃ deposition. These films were polycrystalline. Depending on growth conditions and substrates employed, these films had also possessed a parasitic phase. This phase can be removed by post-deposition annealing in oxidizing ambient. Morphology of the films was characterized by well-packed spherical mounds. Optical measurements exhibited that the bandgap of pure Eu₂O₃ phase was 4.4 eV. High frequency 1 MHz capacitance–voltage (C–V) measurements showed that the dielectric constant of pure Eu₂O₃ film was about 12. Possible effects of cation and oxygen deficiency and parasitic phase on the optical and electrical properties of Eu₂O₃ films have been briefly discussed.     

The location and extent of exfoliation of clay on the fracture mechanisms in nylon 66-based ternary nanocomposites

The primary focus of this work is to elucidate the location and extent of exfoliation of clay on fracture (under both static and dynamic loading conditions) of melt-compounded nylon 66/clay/SEBS-g-MA ternary nanocomposites fabricated by different blending sequences. Distinct microstructures are obtained depending on the blending protocol employed. The state of exfoliation and dispersion of clay in nylon 66 matrix and SEBS-g-MA phase are quantified and the presence of clay in rubber is shown to have a negative effect on the toughness of the nanocomposites. The level of toughness enhancement of ternary nanocomposites depends on the blending protocol and the capability of different fillers to activate the plastic deformation mechanisms in the matrix. These mechanisms include: cavitation of SEBS-g-MA phase, stretching of voided matrix material, interfacial debonding of SEBS-g-MA particles, debonding of intercalated clay embedded inside the SEBS-g-MA phase, and delamination of intercalated clay platelets. Based on these results, new insights and approaches for the processing of better toughened polymer ternary nanocomposites are discussed.     

Remarks on some aspects of language structure and their relevance to pattern analysis

Some specific aspects of language structure are examined in detail in the context of pattern analysis. In particular, a transformational grammar is constructed for a class of patterns, following the linguistic formulation very closely, by taking a simple example and working it out in detail. Many of the characteristics of the transformational grammars of linguists show up even in this simple example. The need for looking for grammars of different styles and the problem of making meaningful assignment of probabilities to sentences in the context of transformational grammars have also been briefly discussed.     

Modal characterizations of controllability and observability in time delay systems

New characterizations of controllability and observability in linear, time-invariant time delay systems are derived. An explicit criterion for stabilizability in terms of system parameters is obtained. Applications of these results are indicated.