250 research outputs found
A radioactively durable melamine-styrene based polymer: Highly efficient removal of Sr-90
No full textRemoval of strontium has a vital importance for radioactive waste management due to its long half-life. In this context, melamine-styrene based polymer (MSBP) was synthesized and characterized by different spectrophotometric methods. Sr2+ ions were removed from the solution using MSBP sorbent. In this respect, adsorption of Sr(2+)onto melamine-based polymer was studied as a part of pH, amount of adsorbent, initial Sr(2+)concentration, contact time, temperature and particle size. Also, adsorption rate of radioactive strontium was investigated by using LSC (Liquid Scintillation Counter). The adsorption data were fitted to Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models. MSBP sorbent reached maximum adsorption capacity for Sr2+ as 142.9 mg.g(-1). Thermodynamic parameters such as free energy (Delta G(0)), entropy (Delta S-0) and enthalpy (Delta H-0) of Sr2+ adsorption on MSBP were examined at five different temperatures of 293 K, 303 K, 313 K, 323 K and 333 K. 0 Delta G(0) and 0 < Delta S-0 revealed that Sr2+ adsorption on MSBP occurred spontaneously and irreversible, respectively. Pseudo first and second orders were investigated as a part of kinetic parameters and seen that pseudo second order was much more convenient for adsorption of Sr2+ onto MSBP
Novel approach with polyfluorene/polydisulfide copolymer binder for high-capacity silicon anode in lithium-ion batteries
No full textIn this study, as a novel design with the collaboration of a fluorene and sulfide-based copolymer for Li-ion battery application is presented. Polyfluorene-co-polydisulfide is prepared with desired functional groups to yield a conductivity and good adhesion. These critical and important features are performed by preparing polymers with proper functional groups. The preparation process is accomplished via Suzuki coupling process under Pd catalyst by combining separately synthesized 4,4 '-dibromodiphenyl disulfide in combination with 9,9-dioctylfluorene-2,7-bis(trimethylborate). The fully obtained capacity of the silicon particles, that is, at C/10 with the capacity of 1250 mAh g(-1) after the 500th cycle, approves the good performance by preserving capacity stability till 600th cycles. The designed and synthesized polymer binder with different functionalities and carbon nanotube additive show better characteristics such as conductivity, high polarity, and binding adhesion. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48303
Provenance-based trust for grid computing: Position Paper
No full textCurrent evolutions of Internet technology such as Web Services, ebXML, peer-to-peer and Grid computing all point to the development of large-scale open networks of diverse computing systems interacting with one another to perform tasks. Grid systems (and Web Services) are exemplary in this respect and are perhaps some of the first large-scale open computing systems to see widespread use - making them an important testing ground for problems in trust management which are likely to arise. From this perspective, today's grid architectures suffer from limitations, such as lack of a mechanism to trace results and lack of infrastructure to build up trust networks. These are important concerns in open grids, in which "community resources" are owned and managed by multiple stakeholders, and are dynamically organised in virtual organisations. Provenance enables users to trace how a particular result has been arrived at by identifying the individual services and the aggregation of services that produced such a particular output. Against this background, we present a research agenda to design, conceive and implement an industrial-strength open provenance architecture for grid systems. We motivate its use with three complex grid applications, namely aerospace engineering, organ transplant management and bioinformatics. Industrial-strength provenance support includes a scalable and secure architecture, an open proposal for standardising the protocols and data structures, a set of tools for configuring and using the provenance architecture, an open source reference implementation, and a deployment and validation in industrial context. The provision of such facilities will enrich grid capabilities by including new functionalities required for solving complex problems such as provenance data to provide complete audit trails of process execution and third-party analysis and auditing. As a result, we anticipate that a larger uptake of grid technology is likely to occur, since unprecedented possibilities will be offered to users and will give them a competitive edge
Replication Data for: Vortex imprints on a free surface as proxy for surface divergence
No full textThis is a complementary data and computer code set to the accepted manuscript "Vortex imprints on a free surface as proxy for surface divergence". It contains the surface layer of the DNS data set used and the code to analyse it in the ways described in the article. The work was funded by the European Union (ERC, WaTurSheD grant 101045299) and the Research Council of Norway (iMod, grant 325114). The research by A. Xuan and L. Shen is also supported by the Office of Naval Research and National Science Foundation. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them
Two-loop Sudakov form factor in ABJM
No full textThis article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited
Fabrication and characterization of Ga-doped ZnO / Si heterojunction nanodiodes
No full text32nd International Physics Congress of Turkish-Physical-Society (TPS) -- SEP 06-09, 2016 -- Bodrum, TURKEYIn this study, temperature-dependent electrical properties of n-type Ga-doped ZnO thin film / p-type Si nanowire heterojunction diodes were reported. Metal-assisted chemical etching (MACE) process was performed to fabricate Si nanowires. Ga-doped ZnO films were then deposited onto nanowires through chemical bath deposition (CBD) technique to build three-dimensional nanowire-based heterojunction diodes. Fabricated devices revealed significant diode characteristics in the temperature range of 220 - 360 K. Electrical measurements shown that diodes had a well-defined rectifying behavior with a good rectification ratio of 10(3) +/- 3 V at room temperature. Ideality factor (n) were changed from 2.2 to 1.2 with increasing temperature.Turkish Phys SocResearch Projects Unit of Omer Halisdemir University [FEB 2014/25-BAGEP, FEB 2014/26-BAGEP]G.A. and F.A.A. would like to give thanks to Research Projects Unit of Omer Halisdemir University (The Project Code: FEB 2014/25-BAGEP and The Project Code: FEB 2014/26-BAGEP) for the financial support
An investigation of the drying process in pickering foams
No full textPickering foams, aqueous foams stabilized by solid particles, can be used as a precursor to fabricate solid porous polymers, ceramics, and composite materials. The fabrication process usually comprises of two subsequent steps of drying and solidification (e.g. sintering) after foam is prepared. Drying (or aging) in aqueous Pickering foams is a complex transport process which involves evaporation and drainage (induced by gravity) of the excess liquid along with deformation of the foam and possible formation of cracks caused by capillary-induced stresses. Crack formation is therefore depended on the drying conditions and the mechanical properties of sample. A comprehensive understanding of the drying process can provide us with predictive tools to select efficient process parameters (e.g. required drying time prior to sintering) as well as providing input prameters for developing numerical models. In this thesis, we first provide experimental data (end of drying time, average moisture content, and effective moisture diffusivity) on drying of Pickering foams stabilized by polymer particles under controlled conditions (i.e. relative humidity and temperature). Drying curves are presented for samples of various initial thicknesses and shapes on substrates of different hydrophobicity and temperatures. Moisture transport is represented via calculating the effective moisture diffusivity coefficients using method of slope. Also, we investigate drying for a bi-component Pickering foam prepared using Multi-walled Carbon Nanotubes (MWCNTs) and polymer particles. We show that the effective moisture diffusivity increases as the average moisture content decreases for all trials and that all data can be collapsed on a master curve. Also, effective moisture diffusivity increased as initial sample thickness as well as substrate temperature increase. On the other hand, effective moisture diffusivity does not depend strongly on the sample shape and MWCNTs concentration. In next part, we explore the effect of initial sample thickness and shape, substrate temperature and wettability, as well as MWCNTs concentration on the crack formations in the samples. We demonstrate that substrate wettability, initial sample thickness, and MWCNTs concentration have a strong influence on the formation and propagation of cracks. We found that decreasing the wettability of the substrate reduces crack formation. Also, increasing the initial sample thickness reduces crack formation. On the contrary, increasing the MWCNTs concentration increases crack formation for all types of substrates. We demonstrate that substrate temperature and sample shape do not seem to influence crack formation but these parameters influence the crack patterns. Such information can be beneficial in using these foams as a precursor to fabricate porous composite porous materials.Ph.D.Includes bibliographical referencesby Omer S. Alabidalkree
Fabrication of p-type CuO thin films using chemical bath deposition technique and their solar cell applications with Si nanowires
No full text32nd International Physics Congress of Turkish-Physical-Society (TPS) -- SEP 06-09, 2016 -- Bodrum, TURKEYRecently, CuO has attracted much interest owing to its suitable material properties, inexpensive fabrication cost and potential applications for optoelectronic devices. In this study, CuO thin films were deposited on glass substrates using chemical bath deposition technique and post-deposition annealing effect on the properties of the prepared samples were investigated. p-n heterojunction solar cells were then constructed by coating of p-type CuO films onto the vertically well aligned n-type Si nanowires synthesized through MACE method. Photovoltaic performance of the fabricated devices were determined with current voltage (I-V) measurements under AM 1.5 G illumination. The optimal short-circuit current density, open-circuit voltage, fill factor and power conversion efficiency were found to be 3.2 mA/cm(-2), 337 mV, 37.9 and 0.45%, respectively. The observed performance clearly indicates that the investigated device structure could be a promising candidate for high-performance low-cost new-generation photovoltaic diodes.Turkish Phys SocOmer Halisdemir University [FEB 2014/25-BAGEP, FEB 2014/26-BAGEP]F.A.A. and G.A. would like to give thanks to Research Projects Unit of Omer Halisdemir University (The Project Code: FEB 2014/25-BAGEP and The Project Code: FEB 2014/26-BAGEP) for the financial support
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