Characterization and Characteristics of mechanochemically synthesized amorphous fast ionic conductor 50 SISOMO (50AgI-25Ag2O-25MoO3)

Mechanochemically synthesized amorphous 50SISOMO [50AgI-25Ag_2O-25MoO_3] fast ionic conductor shows high ionic conductivity of ~ 6x10^-3 {\Omega}^-1 cm-1 at room temperature. The highest ionic conductivity is achieved for 36 h milled sample, which is more than three orders of magnitude higher than that of crystalline AgI at room temperature. The samples are thermally stable at least up to ~70 {\deg}C. Thermoelectric power studies on 50 SISOMO amorphous fast ionic conductors (a-SIC) have been carried out in the temperature range 300-330K. Thermoelectric power (S) is found to vary linearly with the inverse of the absolute temperature, and can be expressed by the equation -S = [(0.19 \times 10^3/T) + 0.25] mV/K. The heat of transport (q*) of Ag+ ion i.e. 0.19 eV is nearly equal to the activation energy (E) i.e. 0.20 eV of Ag+ ion migration calculated from the conductivity plots indicating that the material has an average structure. This is also in consonance with earlier theories on heats of transport of ions in ionic solids.Comment: Presented in the "National Symposium on Advances in Material Science" held at Gorakhpur, India during 17-19 March 200

Frequency-dependent photothermal measurement of thermal diffusivity for opaque and non-opaque materials; Application to crystals of TIPS-pentacene

We propose the use of a frequency-dependent photothermal measurement as a complement to light-flash, i.e. time-dependent, measurements to determine the through-plane thermal diffusivity of small, thin samples, e.g. semiconducting polymers and small organic molecule crystals. The analysis is extended from its previous use with some opaque conducting polymers to materials with finite absorption coefficients, such as crystals of 6,13-bis(triisopropylsilylethynyl pentacene ("TIPS-pentacene"). Taking into account the finite absorption coefficients of the latter gives a value of diffusivity, D=0.10 mm2/s, much smaller than previously estimated and more consistent with its expected value. We also briefly discuss the effects of coating samples for the measurement to improve their optical properties.Comment: 11 pages, 6 figures, to be published in Journal of Applied Physic

On Identifying a Massive Number of Distributions

Finding the underlying probability distributions of a set of observed sequences under the constraint that each sequence is generated i.i.d by a distinct distribution is considered. The number of distributions, and hence the number of observed sequences, are let to grow with the observation blocklength $n$. Asymptotically matching upper and lower bounds on the probability of error are derived.Comment: Under Submissio

Simulation of 2-way fluid structure interaction in a 3D model combustor

The liner of a gas turbine combustor is a very flexible structure that is exposed to the pressure oscillations that occur in the combustor. These pressure oscillations can be of very high amplitude due to thermoacoustic instability, when the fluctuations of the rate of heat release and the acoustic pressure waves amplify each other. The liner structure is a dynamic mechanical system that vibrates at its eigenfrequencies and at the frequencies by which it is forced by the pressure oscillations to which it is exposed. On the other hand the liner vibrations force a displacement of the flue gas near the wall in the combustor. The displacement is very small but this acts like a distributed acoustic source which is proportional to the liner wall acceleration. Hence liner and combustor are a coupled elasto-acoustic system. When this is exposed to a limit cycle oscillation the liner may fail due to fatigue. In this paper the method and the results will be presented of the partitioned simulation of the coupled acousto-elastic system composed of the liner and the flue gas domain in the combustor. The partitioned simulation uses separate solvers for the flow domain and the structural domain, that operate in a coupled way. In this work 2-way fluid structure interaction is studied for the case of a model combustor for the operating conditions 40–60 kW with equivalence ratio of 0.625. This is done in the framework of the LIMOUSINE project. Computational fluid dynamics analysis is performed to obtain the thermal loading of the combustor liner and finite element analysis renders the temperature, stress distribution and deformation in the liner. The software used is ANSYS workbench V13.0 software, in which the information (pressure and displacement) is also exchanged between fluid and structural domain transiently.</jats:p

The Strongly Asynchronous Massive Access Channel

This paper considers a Strongly Asynchronous and Slotted Massive Access Channel (SAS-MAC) where $K_n:=e^{n\nu}$ different users transmit a randomly selected message among $M_n:=e^{nR}$ ones within a strong asynchronous window of length $A_n:=e^{n\alpha}$ blocks, where each block lasts $n$ channel uses. A global probability of error is enforced, ensuring that all the users' identities and messages are correctly identified and decoded. Achievability bounds are derived for the case that different users have similar channels, the case that users' channels can be chosen from a set which has polynomially many elements in the blocklength $n$, and the case with no restriction on the users' channels. A general converse bound on the capacity region and a converse bound on the maximum growth rate of the number of users are derived.Comment: under submissio