Nature of Nitrogen Incorporation in BiVO4 Photoanodes through Chemical and Physical Methods

In recent years, BiVO4 has been optimized as a photoanode material to produce photocurrent densities close to its theoretical maximum under AM1.5 solar illumination. Its performance is, therefore, limited by its 2.4 eV bandgap. Herein, nitrogen is incorporated into BiVO4 to shift the valence band position to higher energies and thereby decreases the bandgap. Two different approaches are investigated: modification of the precursors for the spray pyrolysis recipe and post-deposition nitrogen ion implantation. Both methods result in a slight red shift of the BiVO4 bandgap and optical absorption onset. Although previous reports on N-modified BiVO4 assumed individual nitrogen atoms to substitute for oxygen, X-ray photoelectron spectroscopy on the samples reveals the presence of molecular nitrogen (i.e., N-2). Density functional theory calculations confirm the thermodynamic stability of the incorporation and reveal that N-2 coordinates to two vanadium atoms in a bridging configuration. Unfortunately, nitrogen incorporation also results in the formation of a localized state of approximate to 0.1 eV below the conduction band minimum of BiVO4, which suppresses the photoactivity at longer wavelengths. These findings provide important new insights on the nature of nitrogen incorporation into BiVO4 and illustrate the need to find alternative lower-bandgap absorber materials for photoelectrochemical energy conversion applications

Análisis y propuestas de mejora para una empresa en marcha: caso Instituto Psicopedagógico EOS Perú

En los últimos años, la psicología y la educación han atravesado un proceso de revalorización por parte de la sociedad peruana. Pese al crecimiento económico y a las reformas realizadas en el sistema educativo, se han puesto en evidencia el déficit en la calidad de la prestación tanto pública como privada, los diversos problemas que afronta la población escolar y la necesidad de potenciar este aspecto como parte del desarrollo integral que debiesen tener los niños y jóvenes que serán los futuros actores y conductores de nuestra sociedad. Dentro de estos problemas, existe un gran número de casos que escapan al alcance del docente debido a su complejidad y en la que es necesaria la intervención de un psicólogo. Es en este contexto en el que se desarrollan los centros e institutos psicopedagógicos, organizaciones especializadas en resolver los problemas con trasfondos psicológicos y que afectan el proceso de aprendizaje. Estas organizaciones apuntan a mejorar no sólo el rendimiento escolar de la población, sino su calidad de vida a través del diagnóstico y tratamiento de diversos problemas o trastornos, que pueden abarcar problemas específicos del aprendizaje, del lenguaje, déficit de atención e hiperactividad, aspectos emocionales y conductuales, entre otros. Uno de los principales centros en Lima Metropolitana es el Instituto Psicopedagógico EOS Perú. Pese a contar con no muchos años en el mercado, EOS Perú ha registrado un constante crecimiento que le ha permitido consolidar su posición en el mercado. A través del presente proyecto profesional, y mediante el uso de herramientas de gestión, se ha realizado un diagnóstico de esta organización con el fin de identificar sus principales deficiencias y ventajas en el mercado. Finalmente, se exponen los resultados del análisis y con base en ello, se propone un plan de desarrollo organizacional, abarcando cada área del negocio. Estas propuestas de mejora fueron desarrolladas en base a la información cualitativa y cuantitativa recopilada por el equipo que realiza el presente proyecto y gracias al apoyo de la plana administrativa y académica de EOS Perú.Trabajo de suficiencia profesiona

Size- and density-controlled deposition of Ag nanoparticle films by a novel low-temperature spray chemical vapour deposition method—research into mechanism, particle growth and optical simulation

Ag nanoparticles have attracted interest for plasmonic absorption enhancement of solar cells. For this purpose, well-defined particle sizes and densities as well as very low deposition temperatures are required. Thus, we report here a new spray chemical vapour deposition method for producing Ag NP films with independent size and density control at substrate temperatures even below 100 °C, which is much lower than for many other techniques. This method can be used on different substrates to deposit Ag NP films. It is a reproducible, low-cost process which uses trimethylphosphine (hexafluoroacetylacetonato) silver as a precursor in alcoholic solution. By systematic variation of deposition parameters and classic experiments, mechanisms of particle growth and of deposition processes as well as the low decomposition temperature of the precursor could be explained. Using the 3D finite element method, absorption spectra of selected samples were simulated, which fitted well with the measured results. Hence, further applications of such Ag NP films for generating plasmonic near field can be predicted by the simulation

Resistant Starch and Starch Thermal Characteristics in Exotic Corn Lines Grown in Temperate and Tropical Environments

Corn as a food that is heated and cooled to allow starch retrogradation has higher levels of resistant starch (RS). Increasing the amount of RS can make corn an even healthier food and may be accomplished by breeding and selection, especially by using exotic germplasm. Sixty breeding lines of introgressed exotic germplasm backgrounds, selected for high yield, were grown in three tropical and temperate locations and analyzed for starch thermal characteristics and RS levels. Although actual values for all starch characteristics were within normal levels, most characteristics had significant genotypic effects, and all had significant location effects. Thermal properties of retrograded starch were more influenced by the environment than the thermal properties of raw starch, making retrograded starch traits more heritable than raw starch traits. This suggests that a breeding strategy based on retrograded starch traits will have a better chance of success than a breeding strategy based on raw starch traits. A significant genotype effect for RS levels indicates that genotypic selection to raise the level of RS and increase the healthful aspects of corn food should be successful. Significant location effects indicate that breeders using winter nurseries to accelerate their breeding progress need to be careful when making selections using RS data collected on seed grown in the tropics. A small but highly significant correlation between RS and some thermal characteristics, especially percentage of retrogradation, indicates that we may be able to select promising genotypes for RS selection based on our extensive database of thermal characteristics collected on a wide number of diverse corn lines

Deep Underground Science and Engineering Laboratory - Preliminary Design Report

The DUSEL Project has produced the Preliminary Design of the Deep Underground Science and Engineering Laboratory (DUSEL) at the rehabilitated former Homestake mine in South Dakota. The Facility design calls for, on the surface, two new buildings - one a visitor and education center, the other an experiment assembly hall - and multiple repurposed existing buildings. To support underground research activities, the design includes two laboratory modules and additional spaces at a level 4,850 feet underground for physics, biology, engineering, and Earth science experiments. On the same level, the design includes a Department of Energy-shepherded Large Cavity supporting the Long Baseline Neutrino Experiment. At the 7,400-feet level, the design incorporates one laboratory module and additional spaces for physics and Earth science efforts. With input from some 25 science and engineering collaborations, the Project has designed critical experimental space and infrastructure needs, including space for a suite of multidisciplinary experiments in a laboratory whose projected life span is at least 30 years. From these experiments, a critical suite of experiments is outlined, whose construction will be funded along with the facility. The Facility design permits expansion and evolution, as may be driven by future science requirements, and enables participation by other agencies. The design leverages South Dakota's substantial investment in facility infrastructure, risk retirement, and operation of its Sanford Laboratory at Homestake. The Project is planning education and outreach programs, and has initiated efforts to establish regional partnerships with underserved populations - regional American Indian and rural populations

Development of a NdFe-steel hybrid wiggler for SSRL

A NdFe-steel hybrid configured permanent magnet wiggler, is being developed for insertion in the SPEAR ring at the Stanford Synchrotron Radiation Laboratory, SSRL. Featuring 15 complete periods, a 12.9-cm magnetic period length, and a peak magnetic field range of 0.01 to 1.4 Tesla, the wiggler, was designed to provide an intense radiation source for the National Laboratory/University of California participating research team (PRT) facility on Beam Line VIII-W. A new permenent magnet material, neodymium-iron (NdFe), is being used in the magnetic structure instead of rare-earth cobalt, REC, used previously in the 27-period wiggler now on Beam Line VI. NdFe advantages include a 16% higher coercive force (10.6-kOe vs 9.0-kOe) and lower cost. The wiggler design features a thin walled, rigid vacuum chamber with pole pockets on opposing surfaces allowing a 2.1-cm minimum magnetic gap with a 1.8-cm beam vertical aperture. At 3 GeV the wiggler at peak field is expected to radiate approximately two kilowatts in a 5-mrad horizontal fan with a 7.8 keV critical energy. Calculations are in progress to model the wiggler radiation spatial and spectral radiation emission

The role of the systematic inflammatory response in predicting outcomes in patients with advanced inoperable cancer: systematic review and meta analysis

Introduction: Cancer remains a leading cause of death worldwide. While a curative intent is the aim of any surgical treatment many patients either present with or go onto develop disseminated disease requiring systemic anti-cancer therapy with a palliative intent. Given their limited life expectancy appropriate allocation of treatment is vital. It is recognised that systemic chemoradiotherapy may shorten the quality/quantity of life in patients with advanced cancer. It is against this background that the present systematic review and meta-analysis of the prognostic value of markers of the systemic inflammatory response in patients with advanced cancer was conducted. Methods: An extensive literature review using targeted medical subject headings was carried out in the MEDLINE, EMBASE, and CDSR databases until the end of 2016. Titles were examined for relevance and studies relating to duplicate datasets, that were not published in English and that did not have full text availability were excluded. Full texts of relevant articles were obtained and were then examined to identify any further relevant articles. Results: The majority of studies were retrospective. The systemic inflammatory response, as evidenced by a number of markers at clinical thresholds, was reported to have independent prognostic value, across tumour types and geographical locations. In particular, C-reactive protein (CRP, 63 studies), albumin (33 studies) the Glasgow Prognostic Score (GPS, 44 studies) and the Neutrophil Lymphocyte Ratio (NLR, 59 articles) were consistently validated across tumour types and geographical locations. There was considerable variation in the thresholds reported to have prognostic value when CRP and albumin were examined. There was less variation in the thresholds reported for NLR and still less for the GPS. Discussion: The systemic inflammatory response, especially as evidenced by the GPS and NLR, has reliable prognostic value in patients with advanced cancer. Further prospective studies of their clinical utility in randomised clinical trials and in treatment allocation are warranted

Femtosecond time-resolved two-photon photoemission studies of ultrafast carrier relaxation in Cu_2O photoelectrodes

Cuprous oxide (Cu_2O) is a promising material for solar-driven water splitting to produce hydrogen. However, the relatively small accessible photovoltage limits the development of efficient Cu_2O based photocathodes. Here, femtosecond time-resolved two-photon photoemission spectroscopy has been used to probe the electronic structure and dynamics of photoexcited charge carriers at the Cu_2O surface as well as the interface between Cu_2O and a platinum (Pt) adlayer. By referencing ultrafast energy-resolved surface sensitive spectroscopy to bulk data we identify the full bulk to surface transport dynamics for excited electrons rapidly localized within an intrinsic deep continuous defect band ranging from the whole crystal volume to the surface. No evidence of bulk electrons reaching the surface at the conduction band level is found resulting into a substantial loss of their energy through ultrafast trapping. Our results uncover main factors limiting the energy conversion processes in Cu_2O and provide guidance for future material development