Electronic properties of ion-implanted yttria-stabilized zirconia

Ion implantation of iron and titanium has been applied to modify the surface properties of polycrystalline yttria-stabilized zirconia ((ZrO2)0.87(YO1.5)0.13 (YSZ)) discs in an attempt to prepare surfaces with a mixed conductivity and by this an enhanced surface oxygen exchange kinetics. Surface-sensitive spectroscopic techniques were applied to investigate the implanted layers as a function of different pretreatments such as oxidation, reduction and annealing. Depth profiles were recorded by Rutherford Backscattering Spectroscopy (RBS) and X-ray Photoelectron Spectroscopy (XPS) in combination with sputtering. Ion Scattering Spectroscopy (ISS) and XPS were used to investigate the surface composition and valency of implanted ions. Electronic properties like the band gap, the work function and the energy difference between the Fermi level and valence band edge (EF-EV) were obtained from Ultraviolet Photoelectron Spectroscopy (UPS) and Electron Energy Loss Spectroscopy (EELS). Overlayers of Fe2O3 or TiO2 are formed during oxidation of as-implanted samples. The Fe- and Ti-oxides could be reduced in hydrogen to the oxidation states Fe2+, Fe0 or Ti3+. Annealing of the samples leads to decreased surface concentrations of the implanted ions due to in-diffusion. At the surface of the annealed iron-implanted samples, Fe2+ and metallic Fe could be generated after further reduction whereas at the surface of the annealed Ti-implanted samples only Ti4+ was detectable.\u

Vergleich der Bundesländer: Analyse der Erfolgsfaktoren für den Ausbau der Erneuerbaren Energien 2012 - Indikatoren und Ranking. Endbericht: Forschungsprojekt des DIW Berlin und des ZSW Stuttgart im Auftrag und in Kooperation mit der Agentur für Erneuerbare Energien e.V. Berlin

Die vorliegende Studie wurde von Februar bis September 2012 in Kooperation des Deutschen Instituts für Wirtschaftsforschung (DIW Berlin) mit dem Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW) und der Agentur für Erneuerbare Energien (AEE) erstellt. Die Datenerfassung wurde Anfang Juni 2012 abgeschlossen. Zu den Informationsgrundlagen haben dankenswerterweise die zuständigen Landesministerien sowie zahlreiche Vertreter von Fachverbänden Erneuerbarer Energien und von Industrie- und Handelskammern im Rahmen von Befragungen wesentlich beigetragen. In Kapitel 2 werden zunächst konzeptionelle und methodische Aspekte der Indikatorenanalyse sowie Fragen der Datenverfügbarkeit erläutert. Kapitel 3 enthält eine vollständige Darstellung der ermittelten Einzelindikatoren im Ländervergleich. Auf dieser Basis werden in Kapitel 4 die Einzelindikatoren zu Gruppenindikatoren und zu einem Gesamtindikator für ein übergreifendes Ranking der Bundesländer im Bereich Erneuerbare Energien zusammengefasst. Eine Analyse nach Bundesländern im Hinblick auf Best Practice erfolgt in Kapitel 5. Kapitel 6 enthält eine kurze Zusammenfassung der Ergebnisse. Weitere Details werden im Anhang dokumentiert

The Way to Increased Airplane Engine Power

The purpose of this paper is to give an outline of the present state of development and point out the possibilities available for the further increase in the power/displacement ratio, the economy, and the reliability of the engine. Some of the aspects discussed are methods of increasing take-off power, the various methods of preparation of the fuel mixture and their effect on power, economy, and safety

An Analysis of the Relationship Between Mathematics Beliefs and Mathematics Teaching Self-Efficacy in Elementary Pre-tenured Teachers

Preparing students to be college and career ready with 21st century skills requires elementary classroom teachers to effectively understand and execute the Common Core State Standards for Mathematics. In order to achieve this goal successfully, teachers need to possess both positive mathematics beliefs and mathematics teaching self-efficacy. The purpose of this study was to investigate the possible relationship between mathematics beliefs and mathematics teaching self-efficacy in pre-tenured elementary teachers in Title I schools as well as the relationship of these constructs with demographic factors such as grade level taught, number of years teaching (0-3), level and number of mathematics courses completed in high school and college, and completion of a mathematics degree. While there has been extensive research on the teaching self-efficacy for pre-service teachers, there is a paucity of research focusing on pre-tenured teachers. An online survey based on a validated instrument, the Mathematics Teaching Efficacy Beliefs Instrument, was administered to a representative sample of 125 pre-tenured elementary teachers. A moderate relationship between mathematics beliefs and mathematics teaching self-efficacy was found. Further, it appears that the greater the numbers of mathematics courses completed (high school or undergraduate), the greater the mathematics teaching self-efficacy. No other significant relationships were found with any other variable tested. Implications regarding these findings and possible next steps are examined

Plasma treatment in textile industry

Plasma technology applied to textiles is a dry, environmentally- and worker-friendly method to achieve surface alteration without modifying the bulk properties of different materials. In particular, atmospheric non-thermal plasmas are suited because most textile materials are heat sensitive polymers and applicable in a continuous processes. In the last years plasma technology has become a very active, high growth research field, assuming a great importance among all available material surface modifications in textile industry. The main objective of this review is to provide a critical update on the current state of art relating plasma technologies applied to textile industryFernando Oliveira (SFRH/BD/65254/2009) acknowledges Fundacao para a Cioncia e Tecnologia, Portugal, for its doctoral grant financial support. Andrea Zille (C2011-UMINHO-2C2T-01) acknowledges funding from Programa Compromisso para a Cioncia 2008, Portugal

Supercritical fluid growth of porous carbon nanocages

Carbon nanocages, with remarkably large mesoporous volumes, have been synthesized by the deposition of p-xylene over a Co/Mo catalyst in supercritical carbon dioxide. Nanocages with diameters ranging between 10 and 60 nm were synthesized at temperatures between 650 and 750 °C. The surface area and pore volume of the nanocages produced was found to depend on the reaction temperature and pressure employed. In particular, carbon nanocages with a pore volume of up to 5.8 cm3 g-1 and a BET surface area of 1240 m2 g-1 were readily synthesized at a temperature of 650 °C and a pressure of 10.34 MPa. The high pore volume and surface area of the carbon nanocages synthesized makes them ideal materials for use as inert adsorbents and catalytic supports

Hall Measurements on Carbon Nanotube Paper Modified With Electroless Deposited Platinum

Carbon nanotube paper, sometimes referred to as bucky paper, is a random arrangement of carbon nanotubes meshed into a single robust structure, which can be manipulated with relative ease. Multi-walled carbon nanotubes were used to make the nanotube paper, and were subsequently modified with platinum using an electroless deposition method based on substrate enhanced electroless deposition. This involves the use of a sacrificial metal substrate that undergoes electro-dissolution while the platinum metal deposits out of solution onto the nanotube paper via a galvanic displacement reaction. The samples were characterized using SEM/EDS, and Hall-effect measurements. The SEM/EDS analysis clearly revealed deposits of platinum (Pt) distributed over the nanotube paper surface, and the qualitative elemental analysis revealed co-deposition of other elements from the metal substrates used. When stainless steel was used as sacrificial metal a large degree of Pt contamination with various other metals was observed. Whereas when pure sacrificial metals were used bimetallic Pt clusters resulted. The co-deposition of a bimetallic system upon carbon nanotubes was a function of the metal type and the time of exposure. Hall-effect measurements revealed some interesting fluctuations in sheet carrier density and the dominant carrier switched from N- to P-type when Pt was deposited onto the nanotube paper. Perspectives on the use of the nanotube paper as a replacement to traditional carbon cloth in water electrolysis systems are also discussed