Enhanced Self-organized Dewetting of Ultrathin Polymer Films under Water-organic Solutions: Fabrication of Sub-micron Spherical Lens Arrays

Field-induced self-organized patterning in ultrathin (< 100 nm) polymer films produces resolutions of the order of 10 {\mu}m or more because of the high energy penalty for the surface deformations on small scales. We propose here a very simple but versatile method to fabricate sub-micron (~100 nm) ordered and tunable polymeric structures by self-organized room temperature dewetting of ultrathin polystyrene films by minimizing the surface tension limitation. We illustrate this technique by fabricating sub-micron lens arrays of tunable curvature. This is achieved by switching to controlled room temperature dewetting under an optimal mix of water, acetone and methyl-ethyl ketone (MEK). Organic solvents used decrease the glass transition temperature, greatly decrease the interfacial tension, intensify the field and increase the contact angle/aspect ratio of the resulting tunable nano-structures, without a concurrent solubilization of PS owing to water being the majority phase in the outside mixture.Comment: 13 pages and 5 figure

Visualizing the underlying trends of component latencies affecting service operation performance

This paper presents a technology agnostic method for extracting the underlying distinct patterns of variations in the overall performance of a service operation for changes to different application components supporting the service operation in a computer based service provider to consumer contract. This short paper advocates that visualizing these patterns would help in early projection of the operation's performance due to modification of the application components/processing catering to the operation, without the need of repetitive performance and load testing of the whole service. Lookup datasets against different component configurations are created to associate the variability of component processing impedances to the service operation's performance and best fit regression types are applied to enable trend extrapolation and interpolation

A thin film model for corotational Jeffreys fluids under strong slip

We derive a thin film model for viscoelastic liquids under strong slip which obey the stress tensor dynamics of corotational Jeffreys fluids.Comment: 3 pages, submitted to Eur. Phys. J.

Nanotechnology and Nanomaterials for New and Sustainable Energy Engineering

Role of nanotechnology and nanomaterials for utilization, storage and generation of hydrogen energy, generation of environment friendly thermoelectric power, generation of geothermal energy and photovoltaic or solar energy has been explored. Graphene nanosheet has emerged as a promising material for Platinum catalyst support of fuel cell to enhance electrochemically active surface area and power generation. Graphene and graphene based nanocomposites namely graphene-Polyaniline (PANI) are explored as promising alternatives for hydrogen storage. Inorganic-organic nanocomposite electrolyte membranes comprising of nanosize inorganic building block offers higher proton conductivity, ion exchange capacity and enhanced power generation when applied in a fuel cell. Nanostructured thermoelectric material enhances the power factor and figure of merit. Inorganic (bismuth telluride) –organic (conducting polymer) nanocomposites are explored as a new class of thermoelectric material. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3528

Social Percolation and the Influence of Mass Media

Mass media shift the percolative phase transition observed in the marketing model of Solomon and Weisbuch.Comment: 6 pages including 4 figure

Nanostructures of Polyaniline with Organic and Inorganic Dopants for Sensing of Ammonia

Nanostructured samples of polyaniline (PANI) doped with different dopants (organic and inorganic) have been synthesized employing polymerization and electrodeposition. The influence of nature of dopants( organic and inorganic) and process variation on the room temperature electrical conductivity and on ammonia vapour sensing performance (response percentage and response time) has been investigated. The synthesized samples have been structurally characterized by transmission electron microscopy (TEM) and fourier transform infrared (FTIR) spectra. Regardless of type of dopants, polymerization produces nanospheres of PANI and electrodeposition leads to formation of nanorod-like structures. Among all the synthesized samples, the organic doped electrodeposited sample exhibits highest conductivity. The conductivity of the prepared samples ware measured as a function of time after exposure to ammonia indicating that the polymerized samples (both for organic and inorganic dopants) exhibit fastest response (least response time), while the electrodeposited samples show sluggish response. Thus response percentages of different samples are found to depend on the nanostructures which vary with the nature of dopants and process of preparation. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3519

Thermoelectric Characterization of Nanostructures of Bismuth Prepared by Solvothermal Approach

Nanostructured thermoelectric materials being an emerging area of research bismuth (Bi) nanostructures have been developed by solvothermal approach with a change of solvent. Structural characterization revealed that nanorods and nanospheres like structures were generated in the process when the solvent used were only ethylene glycol (EG) and ethylene glycol with absolute ethanol (AE) in the ratio of 1:1 respectively. Electrical properties viz. conductivity (σ) and thermoelectric power(S) have been measured in the temperature range 300K to 400K. From the observed value of σ and S power factor P has been calculated. The property improved for nanosphere like structures. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3525

Synthesis, Characterization and Performance Study of Phosphosilicate Gel-Sulfonated Poly (Ether Ether Ketone) Nanocomposite Membrane for Fuel Cell Application

Phosphosilicate gel – SPEEK (Sulfonated Poly Ether Ether Ketone) hybrid nanocomposite membranes are proposed for performance enhancement of polymer electrolyte fuel cell. The nanocomposite membranes are synthesized and characterized at 50 and 60 weight percent of inorganic loading. Phosphosilicate gel particles of varying size (sub micro to nanometer) are synthesized using sol gel approach followed by grinding using planetary ball mill for different time. Transmission Electron Microscopy (TEM) reveals less than 10 nm particle size for 20 hr grinding. Nano composite membrane having inorganic particles of size less than 10 nm exhibits higher values of proton conductivity, ion exchange capacity and water uptake compared to composite membrane comprising of larger (400 nm and above) inorganic particles. The membrane is assembled with the electrode in the unit cell and the polarization characteristics are measured at different operating temperatures. Performance study reveals that between 70 to 80 C the membrane offers best performance in terms of peak power generation and of allowable load current. For the same conditions 40-50 % nano-enhancement of peak power generation is achieved by reducing the average gel particle size from sub micro to less than 10 nm. At medium temperature (between 70 to 80 C) the nanocomposite membrane offers more than 100 enhancement of peak power generation compared to that generated by SPEEK membrane. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2491

Dewetting of thin films on heterogeneous substrates: Pinning vs. coarsening

We study a model for a thin liquid film dewetting from a periodic heterogeneous substrate (template). The amplitude and periodicity of a striped template heterogeneity necessary to obtain a stable periodic stripe pattern, i.e. pinning, are computed. This requires a stabilization of the longitudinal and transversal modes driving the typical coarsening dynamics during dewetting of a thin film on a homogeneous substrate. If the heterogeneity has a larger spatial period than the critical dewetting mode, weak heterogeneities are sufficient for pinning. A large region of coexistence between coarsening dynamics and pinning is found.Comment: 4 pages, 4 figure