Size-controlled conformal nanofabrication of biotemplated three-dimensional TiO2 and ZnO nanonetworks

Cataloged from PDF version of article.A solvent-free fabrication of TiO2 and ZnO nanonetworks is demonstrated by using supramolecular nanotemplates with high coating conformity, uniformity, and atomic scale size control. Deposition of TiO2 and ZnO on three-dimensional nanofibrous network template is accomplished. Ultrafine control over nanotube diameter allows robust and systematic evaluation of the electrochemical properties of TiO2 and ZnO nanonetworks in terms of size-function relationship. We observe hypsochromic shift in UV absorbance maxima correlated with decrease in wall thickness of the nanotubes. Photocatalytic activities of anatase TiO2 and hexagonal wurtzite ZnO nanonetworks are found to be dependent on both the wall thickness and total surface area per unit of mass. Wall thickness has effect on photoexcitation properties of both TiO2 and ZnO due to band gap energies and total surface area per unit of mass. The present work is a successful example that concentrates on nanofabrication of intact three-dimensional semiconductor nanonetworks with controlled band gap energies

Characterization of a ballistic supermirror neutron guide

We describe the beam characteristics of the first ballistic supermirror neutron guide H113 that feeds the neutron user facility for particle physics PF1B of the Institute Laue-Langevin, Grenoble (ILL). At present, the neutron capture flux density of H113 at its 20x6cm2 exit window is 1.35x10^10/cm^2/s, and will soon be raised to above 2x10^10/cm^2/s. Beam divergence is no larger than beam divergence from a conventional Ni coated guide. A model is developed that permits rapid calculation of beam profiles and absolute event rates from such a beam. We propose a procedure that permits inter-comparability of the main features of beams emitted from ballistic or conventional neutron guides.Comment: 15 pages, 11 figures, to be submitted to Nuclear Instruments and Methods

Multi-Particle Collision Dynamics -- a Particle-Based Mesoscale Simulation Approach to the Hydrodynamics of Complex Fluids

In this review, we describe and analyze a mesoscale simulation method for fluid flow, which was introduced by Malevanets and Kapral in 1999, and is now called multi-particle collision dynamics (MPC) or stochastic rotation dynamics (SRD). The method consists of alternating streaming and collision steps in an ensemble of point particles. The multi-particle collisions are performed by grouping particles in collision cells, and mass, momentum, and energy are locally conserved. This simulation technique captures both full hydrodynamic interactions and thermal fluctuations. The first part of the review begins with a description of several widely used MPC algorithms and then discusses important features of the original SRD algorithm and frequently used variations. Two complementary approaches for deriving the hydrodynamic equations and evaluating the transport coefficients are reviewed. It is then shown how MPC algorithms can be generalized to model non-ideal fluids, and binary mixtures with a consolute point. The importance of angular-momentum conservation for systems like phase-separated liquids with different viscosities is discussed. The second part of the review describes a number of recent applications of MPC algorithms to study colloid and polymer dynamics, the behavior of vesicles and cells in hydrodynamic flows, and the dynamics of viscoelastic fluids

Lattice Boltzmann simulations of soft matter systems

This article concerns numerical simulations of the dynamics of particles immersed in a continuum solvent. As prototypical systems, we consider colloidal dispersions of spherical particles and solutions of uncharged polymers. After a brief explanation of the concept of hydrodynamic interactions, we give a general overview over the various simulation methods that have been developed to cope with the resulting computational problems. We then focus on the approach we have developed, which couples a system of particles to a lattice Boltzmann model representing the solvent degrees of freedom. The standard D3Q19 lattice Boltzmann model is derived and explained in depth, followed by a detailed discussion of complementary methods for the coupling of solvent and solute. Colloidal dispersions are best described in terms of extended particles with appropriate boundary conditions at the surfaces, while particles with internal degrees of freedom are easier to simulate as an arrangement of mass points with frictional coupling to the solvent. In both cases, particular care has been taken to simulate thermal fluctuations in a consistent way. The usefulness of this methodology is illustrated by studies from our own research, where the dynamics of colloidal and polymeric systems has been investigated in both equilibrium and nonequilibrium situations.Comment: Review article, submitted to Advances in Polymer Science. 16 figures, 76 page

Rijit poliüretan köpük malzemelere kabaran alev geciktirici ilavesinin yanma direnci ve zararlı emisyon oluşumuna etkilerinin incelenmesi

In this study, an intumescent flame retardant composed of ammonium polyphosphate/pentaerythritol (2/1) was incorporated in rigid polyurethane foams in 5, 10 and 15 wt %. Effects of the intumescent flame retardant additions on the flame resistance and harmful emissions of the foams were investigated by using cone calorimeter tests. It was determined that the flame resistance of the foam was significantly increased with the addition of the intumescent flame retardant Furthermore, smoke, carbon monoxide and nitrogen monoxide emissions causing suffocation and poisoning were decreased in different ratios with the addition of the intumescent flame retardant. The addition of 15 wt % the intumescent flame retardant into rigid pofrurethane foam resulted in approximately 40 % decrease in the total heat released value and reduced the nitrogen monoxide emission to less than 9 ppm. In this content it was concluded that the intumescent flame retardant synthesized in this study can be preferred as an effective flame retardant material for rigid polyurethane foams due to ensuring better enhancement of flame resistance and harmful emissions

Microwave-Assisted Synthesis of Some 1H-1,2,4-Triazol-3-one Derivatives

4-Amino-5-(methyl/ethyl)-2,4-dihydro-3H-1,2,4-triazol-3-one were synthesized from the reaction of (methyl/ethyl)-ester ethoxycarbonyl hydrazone with hydrazine hydrate and then, converted to corresponding Schiff bases using 9H-fluorene- 3-carbaldehyde. Ester, hydrazide and oxadiazole derivatives were synthesized starting from Schiff bases in three steps. All reactions occurred under conventional conditions and microwave irradiation. The obtained results were compared.KEYWORDS Triazole, oxadiazole, hydrazine hydrate, microwave irradiation

Alkali Treatment to Maximize Adhesion of Polypyrrole Coatings for Electro-Conductive Textile Materials

In this paper polyester fabrics were pretreated with alkaline solution to improve the ability for the fabric surface to bond with polypyrrole (PPy) coating layer. In situ chemical oxidative polymerization of pyrrole monomer was performed on alkali treated polyester fabrics. Then the fabrics were characterized by FTIR and XRD analysis. The tensile properties of the yarns in both warp and weft directions were measured after alkali treatment and PPy coating processes. The abrasion resistance test was performed on PPy coated fabrics with and without alkali treatment. The surface electrical resistivity of PPy coated fabrics were searched. The electromagnetic shielding effectiveness (EMSE) properties of fabrics in terms of reflection, absorption and transmission behaviors were also investigated. A significant EMSE value increase (about 27%) was obtained with alkali treatment

Studies on Parameters Influencing the Performance of Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) in Detecting Prunus Necrotic Ringpot Virus (PNRSV)

In order to have a more detailed understanding of the various factors influencing a reverse transcriptase polymerase chain reaction (RT-PCR), a number of important parameters such as Mg+2, primer, enzyme concentration and others were optimized for the detection of Prunus necrotic ringspot virus (PNRSV). Using a PNRSV isolate with a pair of primers, complementary DNA of viral genome as template, and an appropriate enzyme together with magnesium chloride, the following optimal conditions were identified: primer concentration between 0.2 and 0.0002 pmol µl-1 and 0.06–2 units µl-1 for Taq DNA polymerase enzyme for a 50 µl reaction volume when other parameters were optimum; magnesium chloride concentration less than 2.5 mM; dNTP concentration between 1 and 10 mM. The optimum cDNA amount should be ~360 ng for a 50 µl reaction mixture. When these optimized concentrations and/or values of the main PCR parameters were brought together for a new RT-PCR, a clear and a reliable PNRSV detection having no background was performed from both growth-chamber and field-grown PNRSV-infected plants