Der ProLan-X - Sprachreport

Bei der Realisierung großer Software-Projekte treten immer wieder Probleme auf, was die Koordination der Mitarbeiter, die Ausnutzung der vorhandenen Ressourcen und nicht zuletzt die Qualität der erzeugten Produkte angeht. Um die Vorgänge bei der Produktion von Software durchschaubarer und verständlicher zu machen, versucht man, diese aus der Sicht von Meta-Modellen zu beschreiben. Dabei fließen die individuellen Rahmenbedingungen einer jeden Entwicklungsumgebung ein; die vorhandenen Ressourcen werden ebenso modellien wie die durchzuführenden Tätigkeiten und ihre Abhängigkeiten. Die Beschreibungssprache für den Software-Prozeß ProLan-X dient der (konkreten) Beschreibung der Bestandteile des Meta-Modells MoMo, das ebenfalls in dieser Arbeitsgruppe entwickelt wurde [Schramm]. Die am Projekt beteiligten Personen, Hardware- und Software-Ressourcen und ihre Aufgaben werden in möglichst natürlicher Weise verhaltensorientien beschrieben. Aus dieser Beschreibung kann eine Ablaufumgebung generien werden, die die Durchführung des Projekts unterstützt und protokolliert. Der vorliegende Bericht faßt die Eigenschaften der Sprache ProLan-X zusammen und erläuten ihre Verwendung. Er setzt das MoMo-Modell als bekannt voraus

High-Efficiency Solar Fuel Devices: Protection and Light Management Utilizing TiO2

Global climate change coupled with increasing global energy consumption drives the need for renewable and carbon-neutral alternatives to fossil fuels. Photoelectrochemical devices store solar energy in chemical bonds, and have the potential to provide cost-effective fuel for grid-scale energy storage as well as to serve as a feedstock for the production of carbon-neutral transportation fuels. A widely recognized goal is the demonstration of a monolithically-integrated solar-fuels system that is simultaneously efficient, stable, intrinsically safe, and scalably manufacturable. This thesis presents the development of three separate high-efficiency solar fuel devices protected by thin films of amorphous TiO2, and develops light management strategies to increase the performance of these devices. First, high-efficiency monolithic cells were designed to perform solar water-splitting and CO2 reduction. These designs are driven by high-quality single-crystalline III-V semiconductors that are unstable when placed in direct contact with aqueous electrolytes but can be protected against corrosion by hole-conducting amorphous films. Experimental fabrication and characterization of this tandem device was realized in the form of a fully-integrated water-splitting prototype with a solar-to-hydrogen efficiency of 10% showing stability for over 80 hours of operation. This was followed by the demonstration of water-splitting and CO2 reduction devices enabled by bipolar membranes, which increased stability and alleviated materials-compatibility constraints by creating a pH difference between the anolyte and catholyte, maintained at steady-state. Finally, universal light management strategies were developed using high-aspect-ratio TiO2 nanocones, resulting in an increase in catalyst loading with ultrahigh broadband transmission.</p

A Stabilized, Intrinsically Safe, 10% Efficient, Solar-Driven Water-Splitting Cell Incorporating Earth-Abundant Electrocatalysts with Steady-State pH Gradients and Product Separation Enabled by a Bipolar Membrane

An efficient, stable, and intrinsically safe solar water-splitting device is demonstrated using a III–V tandem junction photoanode, an acid-stable, earth-abundant hydrogen evolution catalyst, and a bipolar membrane. The integrated photoelectrochemical cell operates under a steady-state pH gradient and achieves ≈10% solar-to-hydrogen conversion efficiency, >100 h of stability in a large (>1 cm^2) photoactive area in relation to most previous reports

Nematoides associados à cultura da soja na região integrada de desenvolvimento do Distrito Federal e entorno-RIDE

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Biológicas, Departamento de Fitopatologia, 2015.A Região Integrada de Desenvolvimento do Distrito Federal e Entorno (RIDE) é composta por 22 municípios distribuídos pelos Estados de Goiás (19), Minas Gerais (3) e Distrito Federal. Nessa região a principal commodity é a soja. Um dos principais problemas fitossanitários desta cultura é causado pelo parasitismo de nematoides. Com o objetivo de conhecer os nematoides associados à cultura da soja na RIDE foi realizado um levantamento visando a identificação e quantificação de espécies fitoparasitas relevantes de nematoides associados. Foram coletadas 70 amostras de solo e de plantas de soja em municípios da RIDE para a extração de nematoides de solo e de raízes. Após a extração, os nematoides foram identificados a nível de gênero, espécie e raça e quantificados por grama de raiz e 300 cc de solo. Pratylenchus brachyurus foi identificado por marcador molecular e com base em caracteres morfológicos e morfométricos, bem como os demais gêneros identificados. A identificação de nematoides de galha foi realizada com base no fenótipo das esterases e em marcadores moleculares mediante reações de PCR. Cistos de Heterodera glycines foram extraídos dos solos visando a inoculação de ovos e J2 em plantas de soja hospedeiro-diferenciadoras para a identificação de raças fisiológicas. Identificou-se Pratylenchus brachyurus, Meloidogyne arenaria (EST-A2), M. javanica (EST-J3), M. incognita e Heterodera glycines raça 3 como os principais nematoides causadores de dano econômico à soja na RIDE. Os níveis de infestação para Meloidogyne spp., H. glycines e P. brachyurus variaram entre as amostras analisadas para os diferentes municípios amostrados. Heterodera glycines, Rotylenchulus reniformis e Tylenchorhynchus sp. tiveram o seu primeiro relato no Distrito Federal para a cultura da soja. Foram encontrados também outros nematoides fitoparasitas como Helicotylenchus spp., Criconemoides spp., Trichodorus spp., além de nematoides micófagos (Aphelenchus e Aphelenchoides), bacteriófagos (Acrobeles e Rhabditis), predadores (Mononchida) e onívoros (Dorylaimida) e outros Tylenchina não identificados.The Integrated Development Region of the Federal District and surrounding areas (RIDE) is composed of 22 municipalities distributed in the states of Goiás (19), Minas Gerais (3) and the Federal District. In this region the main commodity is soybean. One of the main phytosanitary problems of this crop is caused by parasitic nematodes. In order to know the nematodes associated with soybean in the RIDE was conducted a survey aimed to identifying and quantify relevant phytoparasitic species and associated nematodes. Seventy samples were collected from soil and soybean roots in the RIDE municipalities for the extraction of soil and root nematodes. After extraction, the nematodes were identified to genus, species and race when possible, then quantified by gram of root and 300 cc of soil. Pratylenchus brachyurus was identified by molecular markers and based on morphological and morphometric characters, as other nematodes. Identification of root-knot nematodes was based on the phenotype of esterase and molecular markers using PCR reactions. Cists of Heterodera glycines were extracted from the soil aiming to inoculate eggs and J2 in host-differentiating soybean genotypes for the identification of physiological races. It was identified Pratylenchus brachyurus, Meloidogyne arenaria (EST-A2), M. javanica (EST-J3), M. incognita and Heterodera glycines race 3 as the main cause of economic damage by nematodes to soybeans in the RIDE. Infestation levels for Meloidogyne spp., H. glycines and P. brachyrus varied among samples analyzed for the different sampled municipalities. This is the first report of Heterodera glycines, Rotylenchulus reniformis and Tylenchorhynchus sp. in the Federal District to soybean crop. Also found other plant parasitic nematodes as Helicotylenchus spp., Criconemoides spp., Trichodorus spp., and mycophagous nematodes (Aphelenchus and Aphelenchoides), bacteriophages (Acrobeles and Rhabditis), predators (Mononchida) and omnivores (Dorylaimida) and other unidentified Tylenchina

Sputtered NiO_x Films for Stabilization of p^+n-lnP Photoanodes for Solar-Driven Water Oxidation

A photoanode protection strategy using a multifunctional NiO_x coating is presented. The ransparency/antireflectivity, low electrochromism, conduction of holes, corrosion protection, and active electrocatalysis for water-oxidation half-reaction are described

Microwave-induced water flow in a microchannel built on a coplanar waveguide

We present experimental and numerical investigations of water flow in a microsystem induced by microwave electric fields. Microwave dielectric heating induces gradients of temperature which produce spatial variations in mass density and dielectric permittivity that lead to buoyancy and dielectric forces in the liquid, respectively. The experimental system consists of a microchannel, filled with water, which is built on top of a coplanar waveguide operating in the fundamental transversal electromagnetic (TEM) mode at frequencies in the range 1–4 GHz. The flow originated by standing waves is studied. Maxima and minima of electric field amplitude lead to maxima and minima of fluid flow. This observation allows us to measure the TEM wavelength and good agreement is found with the theoretical results for the TEM mode inside the microchannel. We also present three dimensional finite-element calculations of the electric, temperature and fluid velocity fields in the microchannel. In a first approach, the calculations are performed using the equations in the limit of small temperature variations, which allows us to decouple the electrical, mechanical and thermal equations. These calculations show a good agreement with the velocity profiles. Subsequently, the effect of considering finite increments of temperature is taken into account and the new numerical results improve the quantitative comparison with experimental velocities.Ministerio de Gobierno español MEC-FIS2006-03645Junta de Andalucía-P09-FQM-458

Solar-Driven Reduction of 1 atm of CO_2 to Formate at 10% Energy-Conversion Efficiency by Use of a TiO_2-Protected III–V Tandem Photoanode in Conjunction with a Bipolar Membrane and a Pd/C Cathode

A solar-driven CO_2 reduction (CO_2R) cell was constructed, consisting of a tandem GaAs/InGaP/TiO_2/Ni photoanode in 1.0 M KOH(aq) (pH = 13.7) to facilitate the oxygen-evolution reaction (OER), a Pd/C nanoparticle-coated Ti mesh cathode in 2.8 M KHCO_3(aq) (pH = 8.0) to perform the CO_2R reaction, and a bipolar membrane to allow for steady-state operation of the catholyte and anolyte at different bulk pH values. At the operational current density of 8.5 mA cm^(–2), in 2.8 M KHCO_3(aq), the cathode exhibited 94% Faradaic efficiency for the reduction of 1 atm of CO_2(g) to formate. The anode exhibited a 320 ± 7 mV overpotential for the OER in 1.0 M KOH(aq), and the bipolar membrane exhibited ∼480 mV voltage loss with minimal product crossovers and >90 and >95% selectivity for protons and hydroxide ions, respectively. The bipolar membrane facilitated coupling between two electrodes and electrolytes, one for the CO_2R reaction and one for the OER, that typically operate at mutually different pH values and produced a lower total cell overvoltage than known single-electrolyte CO_2R systems while exhibiting ∼10% solar-to-fuels energy-conversion efficiency

A Monolithically Integrated, Intrinsically Safe, 10% Efficient, Solar-Driven Water-Splitting System Based on Active, Stable Earth-Abundant Electrocatalysts in Conjunction with Tandem III-V Light Absorbers Protected by Amorphous TiO_2 Films

A monolithically integrated device consisting of a tandem-junction GaAs/InGaP photoanode coated by an amorphous TiO_2 stabilization layer, in conjunction with Ni-based, earth-abundant active electrocatalysts for the hydrogen-evolution and oxygen-evolution reactions, was used to effect unassisted, solar-driven water splitting in 1.0 M KOH(aq). When connected to a Ni-Mo-coated counterelectrode in a two-electrode cell configuration, the TiO_2-protected III-V tandem device exhibited a solar-to-hydrogen conversion efficiency, η_(STH), of 10.5% under 1 sun illumination, with stable performance for > 40 h of continuous operation at an efficiency of η_(STH) >10%. The protected tandem device also formed the basis for a monolithically integrated, intrinsically safe solar-hydrogen prototype system (1 cm^2) driven by a NiMo/GaAs/InGaP/TiO_2/Ni structure. The intrinsically safe system exhibited a hydrogen production rate of 0.81 μL s^(-1) and a solar-to-hydrogen conversion efficiency of 8.6% under 1 sun illumination in 1.0 M KOH(aq), with minimal product gas crossover while allowing for beneficial collection of separate streams of H_2(g) and O_2(g)

Nickel: A very fast diffuser in silicon

Nickel is increasingly used in both IC and photovoltaic device fabrication, yet it has the potential to create highly recombination-active precipitates in silicon. For nearly three decades, the accepted nickel diffusivity in silicon has been DNi(T)=2.3×10exp−3 exp(−0.47 eV/kBT) cm2/s, a surprisingly low value given reports of rapid nickel diffusion in industrial applications. In this paper, we employ modern experimental methods to measure the higher nickel diffusivity DNi(T)=(1.69±0.74)×10exp−4 exp(−0.15±0.04 eV/kBT)  cm2/s. The measured activation energy is close to that predicted by first-principles theory using the nudged-elastic-band method. Our measured diffusivity of nickel is higher than previously published values at temperatures below 1150 °C, and orders of magnitude higher when extrapolated to room temperature.Peer reviewe