Role of microenvironment in the mixed Langmuir-Blodgett films

This paper reports the pi-A isotherms and spectroscopic characteristics of mixed Langmuir and Langmuir-Blodgett (LB) films of non-amphiphilic carbazole (CA) molecules mixed with polymethyl methacrylate (PMMA) and stearic acid (SA). pi-A isotherm studies of mixed monolayer and as well as also the collapse pressure study of isotherms definitely conclude that CA is incorporated into PMMA and SA matrices. However CA is stacked in the PMMA/SA chains and forms microcrystalline aggregates as is evidenced from the scanning electron micrograph picture. Nature of these aggregated species in the mixed LB films has been revealed by UV-Vis absorption and fluorescence spectroscopic studies. The presence of two different kinds of band systems in the fluorescence spectra of the mixed LB films have been observed. This may be due to the formation of low dimensional aggregates in the mixed LB films. Intensity distribution of different band system is highly sensitive to the microenvironment of two different matrices as well as also on the film thicknessComment: 11 pages, 5 figure

Effect of Rapid Thermal Annealing of CIGS Thin Film as an Absorber Layer

The influence of rapid post-deposition thermal annealing (500 °C for 2 minutes) on the CIGS thin films of different thicknesses (0.4 to 1.0 m) has been investigated. The deposition of CIGS is carried out using the flash evaporation at the substrate temperature of 250 °C. The as-grown and annealed CIGS is characterized by XRD, SEM, EDS, TEM, optical transmission, reflection, and electrical measurements. Lowering the thickness of CIGS absorber shows the remarkable influence on crystal structure, surface morphology, and composition of the overall film. Further improvement was observed by the rapid annealing process. Cu-rich composition was observed for annealed CIGS thin film having a thickness below 0.6 μm, while for 1.0 m thickness the composition is slightly Cu-poor and the compactly packed faceted grains observed. Optical band gap near to 1.05 eV and the electrical resistivity in the order of 104 Ωcm shows its future use as an absorber layer for CIGS solar cell. Furthermore, an attempt of making CIGS / CdS hetero-structure shows ideal behavior of the Schottky hetero-structure with the ideality factor of 1.5. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3100

Heuristic Multi-Agent Control for Energy Management of Microgrids with Distributed Energy Sources

The increased integration of distributed Renewable Energy Sources (RESs) and adoption of Electric Vehicles (EVs) require appropriate control and management of energy sources and EV charging. This becomes critical at the distribution system level, especially at a microgrid (MG) level. This control is required not only to mitigate the negative impacts of intermittent generation from RESs but also to make better use of available energy, reduce carbon footprint, maximize the overall profit of microgrid and increase energy autonomy by effective utilization of battery storage. This paper proposes a heuristic multi-agent based decentralized energy management approach for grid-connected MG. The MG comprises of active (controlled) and passive (uncontrolled) electrical loads, a photovoltaic (PV) system, battery energy storage system (BESS) and a charging post for electric vehicles. The proposed approach is aimed at optimizing the use of local energy generation from photovoltaic and smart energy utilization to serve electrical loads and EV as well as maximizing MG profit. The aim of the energy management is to supply local consumption at minimum cost and less dependency on the main grid supply. Utilizing energy available from RESs (PV and BESS), customers satisfaction (fulfilling local demand), considering uncertainty of renewable generation and load consumption and also taking into account technical constraint are the main strengths of the presented framework. Performance of the proposed algorithm is investigated under different operating conditions and its efficacy is verified

Formation of polycrystalline SnS layers by a two-step process

Thin films of SnS have been produced by a novel two-stage process. This involved the deposition of thin films of Sn onto glass substrates using d.c. magnetron sputtering followed by conversion of the metallic layers into the compound by annealing in the presence of elemental sulfur. All the layers synthesised were found to be polycrystalline, the grain size and crystallinity of the layers increasing with increasing annealing temperature. The precursor layers sulfurised at temperatures 350°C, were found to be non-stoichiometric and X-ray diffraction data indicated the presence of a range of binary phases other than SnS. The best SnS layers were synthesised for annealing temperatures between 300 and 350°C. These layers were found to be stoichiomentric with a strong {111} preferred orientation. The stoichiometric SnS layers had resistivities of 1.5×102 ?cm and Arrhenius plots of the resistivity gave an activation energy of 0.65 eV. The optical energy band gap of the layers was 1.35 eV. These p-type layers could find application as absorber layers in thin film solar cells

Application of visible and infrared spectroscopy for the evaluation of evolved glauconite

The Oligocene Maniyara Fort Formation in western India exhibits two distinct glauconite types with different maturation states, which are characterized by their spectral response in the visible to infrared spectrum of electromagnetic radiation. Spectral signatures of Maniyara Fort glauconites display absorption features at approximately 0.77, 1.08, 1.9, 2.3 μm in the visible-short-wave infrared (SWIR) and 2.8 and 10 μm in the mid-infrared (MIR) region which vary with K 2O content of glauconite. The spectra of glauconite varies significantly as a function of its cationic contents and substitution in different sites. The maturity is found to increase in tandem with the metal–metal charge transfer (CT) and the Fe 2+ dd absorption band respectively at 1.08 and 0.77 μm. H 2O and OH − signatures at the NIR region reflect differences in the sensitivity of glauconites with different molecular H 2O content. In the MIR region, a gradual shift of the Si–O stretch at 10 μm towards lower wavelengths indicates the dominance of smectite layers in glauconites. This study demonstrates a strong correlation between the proportion of expandable layers in the glauconite structure with variations in characteristic band position, depth and symmetry in reflectance and emissivity

The First Law for Boosted Kaluza-Klein Black Holes

We study the thermodynamics of Kaluza-Klein black holes with momentum along the compact dimension, but vanishing angular momentum. These black holes are stationary, but non-rotating. We derive the first law for these spacetimes and find that the parameter conjugate to variations in the length of the compact direction is an effective tension, which generally differs from the ADM tension. For the boosted black string, this effective tension is always positive, while the ADM tension is negative for large boost parameter. We also derive two Smarr formulas, one that follows from time translation invariance, and a second one that holds only in the case of exact translation symmetry in the compact dimension. Finally, we show that the `tension first law' derived by Traschen and Fox in the static case has the form of a thermodynamic Gibbs-Duhem relation and give its extension in the stationary, non-rotating case.Comment: 20 pages, 0 figures; v2 - reference adde

Processing of aluminum-graphite particulate metal matrix composites by advanced shear technology

Copyright @ 2009 ASM International. This paper was published in Journal of Materials Engineering and Performance 18(9) and is made available as an electronic reprint with the permission of ASM International. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplications of any material in this paper for a fee or for commercial purposes, or modification of the content of this paper are prohibited.To extend the possibilities of using aluminum/graphite composites as structural materials, a novel process is developed. The conventional methods often produce agglomerated structures exhibiting lower strength and ductility. To overcome the cohesive force of the agglomerates, a melt conditioned high-pressure die casting (MC-HPDC) process innovatively adapts the well-established, high-shear dispersive mixing action of a twin screw mechanism. The distribution of particles and properties of composites are quantitatively evaluated. The adopted rheo process significantly improved the distribution of the reinforcement in the matrix with a strong interfacial bond between the two. A good combination of improved ultimate tensile strength (UTS) and tensile elongation (e) is obtained compared with composites produced by conventional processes.EPSR

Evidence for the In‐Situ Generation of Plasma Depletion Structures Over the Transition Region of Geomagnetic Low‐Mid Latitude

On a geomagnetic quiet night of October 29, 2018, we captured an observational evidence of the onset of dark band structures within the field-of-view of an all-sky airglow imager operating at 630.0 nm over a geomagnetic low-mid latitude transition region, Hanle, Leh Ladakh. Simultaneous ionosonde observations over New Delhi shows the occurrence of spread-F in the ionograms. Additionally, virtual and peak height indicate vertical upliftment in the F layer altitude and reduction in the ionospheric peak frequency were also observed when the dark band pass through the ionosonde location. All these results confirmed that the observed depletions are indeed associated with ionospheric F region plasma irregularities. The rate of total electron content index (ROTI) indicates the absence of plasma bubble activities over the equatorial/low latitude region which confirms that the observed event is a mid-latitude plasma depletion. Our calculations reveal that the growth time of the plasma depletion is ∼2 h if one considers only the Perkins instability mechanism. This is not consistent with the present observations as the plasma depletion developed within ∼25 min. By invoking possible Es layer instabilities and associated E-F region coupling, we show that the growth rate increases roughly by an order of magnitude. This strongly suggests that the Cosgrove and Tsunoda mechanism may be simultaneously operational in this case. Furthermore, it is also suggested that reduced F region flux-tube integrated conductivity in the southern part of onset region created conducive background conditions for the growth of the plasma depletion on this night

Effect of Film Thickness and Annealing on the Structural and Optical Properties of CuInAlSe2 Thin Films

CuIn1 – xAlxSe2 (CIAS) thin films were grown using flash evaporation method by varying the film thickness from 500 nm to 700 nm. Prepared CIAS thin films were annealed at 573 K for one hour in vacuum. The influence of film’s thickness and the annealing temperature were characterized by the X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive analysis of X-ray (EDAX), Optical transmission measurements, and Hall Effect measurement. As the film thickness increases the crystallinity improves and due to that the optical absorption also improves. The further improvement for different thicknesses of CIAS thin films were observed by annealing. The thicker (700 nm) and annealed CIAS thin film shows the crystallite size of 24.3 nm, energy band gap of 1.19 eV, and resistivity of about 9 102 Ω cm. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3532