The objective of the present study is to obtain the electrolyte material YSZ at low cost via sol gel, through exploration of the index rate between the complexing agents and the metallic salts (HMTA / metallic salts) from 1 to 5, prepared by a polymeric way in a sol gel process. We show an easy method that could be used in the industrial scale in order to obtain solid electrolyte material for its application in SOFC to operate at temperatures in the range of 700 800°C. This study has as reference the papers from Lenormand and Rieu about their synthesis of zirconium substituted to 8% of yttrium (CYSZ= 0.2 mol*L-1 metallic salts concentration-). The presence of the phase in the materials has been confirmed by X-ray diffraction assisted by thermal analysis tests, for indexes from 2 to 5 at a temperature of 1000°C for 5 hours at a calcination rate (from amorphous dust obtained at 400°C) of 1000°C per hour. The grain size mean for crystalline powder has an average near 50 nm and standard deviation close to 9 nm, it was confirmed by scanning electron microscope (SEM).

Characteristics of surface-adsorbed bioluminescent bacteria were examined. The bacteria were expected to function as an oxygen probe inside the biofilm. Luminescent behavior of the bacteria inside a typical biofilm was observed. Adsorption characteristics as well as the luminescence intensity change through the desorption process were investigated.

Highly efficient Pt-TiO2 composite photoelectrodes were synthesized by combining two novel deposition methods: ACVD and a room temperature RF (radio frequency) magnetron sputtering method. A room temperature RF magnetron sputtering method allowed uniform deposition of Pt nanoparticles (NPs) onto the as-synthesized nanostructured columnar TiO2 films by ACVD. Pt NP sizes from 0.5 to 3 nm demonstrating a high particle density (>1012 cm−2) could be achieved by varying deposition time with constant pressure and power intensity. As-synthesized Pt-TiO2 films were used as photoanodes for water photolysis. Pt nanoparticles deposited onto the TiO2 film for 20s produced the highest photocurrent (7.92 mA/cm2 to 9.49 mA/cm2) and maximized the energy conversion efficiency (16.2 % to 21.2 %) under UV illumination. However, as the size of Pt particles increased, more trapping sites for photogenerated electron-hole pairs decreased photoreaction.

The successful modification of the tips of a cellular microgripper into ion selective electrodes capable of sensing calcium ions at concentrations as low as 8x10-5 M is described. The modification involves applying the process of adding the components of all solid state ion selective electrodes. Specifically, poly(3,4-ethylenedioxythiophene) (PEDOT) is added to a gold electrode protruding from the microgripper tip; this is then coated with a poly(vinyl chloride) PVC based calcium selective membrane. Excellent Nernstian response was observed from our devices, with calibration slopes of 29.5 ± 2.5 mV/dec.

The output power-density and the efficiency of thermo-tunnel devices are examinedas a function of inter-electrode separation, electrode work-function, and temperature. We find that these physical parameters dramatically influence the device characteristics, and under optimal conditions a thermo-tunnel device is capable of delivering a very high output power-density of ∼ 103Wcm−2. In addition, at higher temperatures, the heat-conversion efficiency of the thermo-tunnel device approaches ∼ 10%, comparable to that of a thermoelectric generator. We therefore propose that thermo-tunnel devices are promising for solid-state thermal energy conversion.

The effect of two substituent groups, ortho-methoxy (-OCH3) and methyl (-CH3) in aniline, have been studied for supercapacitor applications. The polyaniline (PANI), poly (o-anisidine) (POA) and poly (o-toluidine) (POT) have been synthesized by oxidative polymerization method, and characterized by Cyclic Voltammetry (CV), UV–visible spectroscopy, Raman spectroscopy, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) techniques. The specific capacitance, charging/discharging and electrochemical impedance characteristics of the supercapacitor fabricated using PANI, POA, as well as POT electrodes are evaluated in 2M H2SO4 electrolytic media. The highest specific capacitance of 400 F/g is calculated for PANI, whereas, POA and POT have exhibited 360 F/g and 325 F/g capacitance in supercapacitor studies.

Monte Carlo simulations are used to perform an atomic scale modelling of the magnetic properties of epitaxial exchange-coupled DyFe2/YFe2 superlattices. These samples, extremely well-researched experimentally, are constituted by a hard ferrimagnet DyFe2 and a soft ferrimagnet YFe2 antiferromagnetically coupled. Depending on the layers and on the temperature, the field dependence of the magnetization depth profile is complex. In this work, we reproduce by Monte Carlo simulations hysteresis loops for the net and compound-specific magnetizations at different temperatures, and assess the quality of the results by a direct comparison to experimental hysteresis loops.

Coffinite (USiO4•nH2O) is a common mineral in uranium ores. It is often observed to replace uraninite during alteration under reducing conditions. However, it has proven difficult to synthesize coffinite in the laboratory and quantitative thermodynamic data for coffinite are lacking. Despite these experimental difficulties, there is ample evidence in nature that many uranium deposits have encountered conditions where formation of coffinite has been favoured over uraninite during postgenetic alteration events. Coffinite is also found as a primary mineral in sandstone uranium deposits. This review elucidates the spatial relation between coffinite and uraninite as seen on different scales with different analytical methods. Some further insight into the mechanism of uraninite alteration in natural, reducing, Si-rich environments is gained and some new arguments put forward, including the question of the effect of impurities and dopants, defects, and grain size. The replacement of uraninite by coffinite is discussed in terms of solid-fluid interaction.

Single layer regions of MoS2 on SiO2 and SrTiO3 were identified by Raman spectroscopy and μ-photoluminescence before Kelvin probe force microscopy was performed. For the already known system MoS2/SiO2 we find 1.839 eV for the direct bandgap, in good agreement with earlier results. On MoS2/SrTiO3 the direct bandgap was determined to be 1.829 eV. From our Kelvin probe data we infer that the SrTiO3 substrate leads to a dipole layer at the interface of the MoS2 single layer. The corresponding μ-PL measurements however show no significant decrease of the bandgap. This shows, that in the case of MoS2 the carrier type as well as concentration is not significantly influenced by the choice of SrTiO3 as the substrate compared to SiO2.

Using the transfer matrix method and the Ben Daniel-Duke equation for variable mass electrons propagation, we calculate the transmittance for a finite superlattice where the potential barriers height follows a linear dependence like that of an inverted “V” letter. The energy dependence of the transmittance presents intervals of stopbands and nearly flat passbands. We calculate these properties for several numbers of barriers as well as for different barrier and wells widths and compare those with a regular superlattice.

The present paper reports the utilization of a boron-doped nanocrystalline diamond film (BDD) in electrochemical oxidization (ECO) process of organic phenol compound in 0.1 M H2SO4 water solution. The nano BDD films were synthesized by microwave plasma chemical vapor deposition (MWPCVD), and then characterized by Raman spectroscopy and SEM before and after the electrochemical oxidation treatment. For the ECO treatment performed to the test sample solution, an observation of the first and the last voltammetric plots exhibited a qualitatively differences between the two plots where the first one represent the initial concentration and the last one the signal produced by the organic solution after treatment. UV-Vis analysis through the application of a standard calibration curve, quantitatively confirmed the composition of phenol remaining in the sample solution subdued to the ECO treatment.

The corrosion behavior of oxygen-free copper in anoxic sulfide solutions under nuclear waste disposal conditions was studied using electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) equipped with a focused ion beam (FIB), X-ray photoelectron spectroscopy (XPS) and Micro X-ray diffraction (μXRD). The film growth process and mechanism were elucidated using an Au marker test, and the contribution of solution diffusion to corrosion was demonstrated in magnetically-stirred experiments. The effect of groundwater chemistry, particularly chloride content on copper corrosion and film properties was characterized using long-term corrosion experiments.

The purpose of this study was to investigate the in vivo biocompatibility of a new composite made from collagen and liposomes coated with plant derived polysaccharide using a rat subcutaneous implantation model. Histological observation has shown that after five days post-implantation, granulation tissue with vascular dilatation and inflammatory cell infiltration was formed adjacent to the implanted scaffold. After two weeks post-implantation, scaffold was highly infiltrated with cells and many of multinucleated giant cells were found to be aligned along the implant/tissue interface. At four weeks the scaffold was completely infiltrated with cells and a fibrous connective capsule isolate the implanted scaffold from the surrounding tissue. The inflammatory response to the implanted scaffold was assessed by immunohistochemical staining for interleukin 1β. IL-1β was demonstrated early in the post-implantation period (five days), but after two weeks, the intensity of IL-1β staining was on the decline. In vivo studies based on histological and immunohistochemical observations showed that throughout the period of implantation, composite scaffold was well tolerated by the host animals and immune responses to the implant were moderate. The observations are consistent with the normal wound healing response to subcutaneous implantation of biomaterials. The results from the in vivo study indicate a good biocompatibility for porous scaffold made from collagen and liposomes coated with plant derived polysaccharide.

A 2010 Report to the President from the Council of Advisors on Science and Technology calls for “research and development to create “well-designed and validated examples of comprehensive, integrated instructional materials” for K-12 education. The Center for Functional Nanoscale Materials (CFNM) at Clark Atlanta University (CAU) and the Center for Science Education at Emory University have partnered in a program that provides a collaborative experience between CAU graduate students and Atlanta area high school and middle school teachers. The partnership expands Emory’s PRISM (Problems and Research to Integrate Science and Mathematics) program, a NSF Graduate Teaching Fellows in K-12 Education (GK-12) program. We believe that personal and experiential collaboration between these stakeholders in materials education provides even more substantial and tangible benefits.

PRISM aims to stimulate reflection, by providing teachers and graduate students (PRISM Fellows) with an opportunity to lead in producing knowledge about pedagogical practice in STEM areas. By direct linkage with pedagogic theory, teaching practice can be subjected to continuous improvement, and it is anticipated that participants will catalyze change in both the educational and research communities.

CFNM/PRISM Program ensures that both categories of Fellows participate in professional development activities designed to propagate active learning pedagogies and reflective practice during an annual Summer Institute. Teachers are immersed in a content-rich nano- and materials science research environment, while the graduate fellows have the opportunity during the subsequent academic year to assist with instruction in local schools. Thirteen graduate students and seventeen teachers have participated in the CFNM/PRISM Program over the course of five years. Teams were formed that comprised a teacher, a CAU faculty researcher and a graduate student. Each team tackled a nanoscience research problem during a summer project, developed problem-based learning (PBL) and investigative case-based learning strategies that integrate grade-appropriate science and math content, and implemented the cases in middle school and high school classrooms.

The program has been preliminarily evaluated using online written attitudinal surveys and interviews with participants. Most striking among our observations is that teachers report an enhancement of their science process skills, including an increased ability to design and implement experiments for their students. Correspondingly, graduate students report a better understanding of the importance and practice of mentoring, as well as improved ability to articulate complex scientific concepts to lay audiences. Finally, since the student body at CAU and in these Atlanta area school systems is predominantly of African American heritage, the project also contributes to diversification of the Nation’s scientific enterprise.

Thermally activated axial intrusion of nickel silicides into the silicon nanowire (NW) from pre-patterned Ni reservoirs is used in formation of nickel silicide/silicon contacts in SiNW field effect transistors. This intrusion consists usually of different nickel silicide phases which grow simultaneously during thermal annealing (TA). The growth is often accompanied by local thickening and tapering of the NW, up to full disintegration of segments adjacent to the silicon. In the present work this process was investigated in SiNWs of 30-60 nm in diameters with pre-patterned Ni electrodes after a TA at 420-440°C and times up to 15 s. The process was analyzed in the framework of a model taking into account simultaneous formation of two silicide phases in the NW. Additional flux of atoms caused by the NW curvature gradients due to different radii of different silicides was taken into account as well. For a certain set of parameters thickening of the nickel-rich silicide intrusion and tapering of the monosilicide part of intrusion were obtained.

An aqueous magnetic suspension was prepared by dispersing amphiphilic co-polymer (ACP) coated monodispersed magnetite nanoparticles (MNPs) synthesized through thermal decomposition of iron(III) acetylacetonate in a mixture of oleic acid and oleylamine. ACP composed of poly (maleic anhydride-alt-1-octadecene) and polyethylene glycol methyl ether was applied to disperse MNPs in water and buffer solution. The average diameter of MNPs increased from 6.6 to 12.5 nm with increasing reaction temperature from 200 to 250°C. Infrared spectra and elemental analysis revealed that the surface modified MNPs contain carboxyl groups originated from oleic acid and ACP. The conjugation of MNPs and bovine serum albumin (BSA) antibody was examined. As a result, the as-synthesized MNPs adsorbed BSA antibody effectively than the surface modified MNPs: the BSA antibody adsorption decreased with increasing cross-linker concentration.

Hydrophobic-oleophobic coatings are often used to provide the transparent electrodes in devices like touch panels and smart windows with protection from fingerprints and other contaminants which may degrade electronic and optical performance. Conventional fluorosilane monolayers or co-condensed films are often surface-enriched with fluorinated moieties due to the thermodynamic drive of these components to migrate to low-surface energy interfaces. Consequently, these conventional coatings may be strongly non-wetting and have low-surface energy when pristine, but upon wear and exposure of the bulk subsurface regions, the films are much less functional. This work explores the use of surfactant templated sol-gel silica films as scaffolds for encapsulating surface-segregating functional organic moieties as a mesoscopically dispersed phase with the goal of imparting sustained functionality. The results show that surfactant template concentration may be used to tune the dispersion of the fluorosilane-rich phase within the silica film in order to allow worn and exposed internal surfaces to maintain much of the original functionality of the pristine top surface.

Cellulose nanofibrils have been evaluated as reinforcement material in polymeric matrixes due to their potential to improve the mechanical, optical, and dielectric properties of these matrixes as well as its environmental positive footprint. This work describes how banana nanocellulose can be used to replace others not so friendly materials in many applications including, biomaterials, automotive industries and packaging by proved with their mechanical properties. The process used is very mild to the environment and consists of a high pressure fibrillation followed by a chemical purification which affects the fiber morphology. Many fibers characterization processes were used including microscopy techniques and X-ray diffraction to study the structure and properties of the prepared nanofibers and composites. Microscopy studies showed that the used individualization processes lead to a unique morphology of interconnected web-like structure of the fibers.