BFO Research Papers - Academia.edu (original) (raw)

El spray pirolisis es una técnica de deposición química en húmedo; se pueden generar aerosoles mediante distintos mecanismos fiscos, como lo son ondas ultrasónicas, gradientes de presión y fuerzas electrostáticas. Como tal, consiste en la atomización de un líquido en pequeñas gotas. Cuando al líquido en forma de películas delgadas se le permite fluir a través de una superficie vibrante, se rompe en finas gotas. Este fenómeno es conocido como atomización ultrasónica. Existen dos hipótesis formuladas para descripción de estos fenómenos, estas son: • Hipótesis de la onda capilar • Hipótesis de cavitación Se enfocara en la hipótesis de cavitación porque generalmente es aplicada a altas frecuencias. Vibrador ultrasónico y características de la niebla que produce Estas atomizaciones se logran por medio de nebulizadores ultrasónicos los cuales están basado en el principio de vibraciones de un cristal piezoeléctrico el cual es manejado por un campo eléctrico alternante. Los ultrasonidos son ondas sonoras generadas por frecuencias mayores 20,000 Hz. A estas frecuencias se ocasiona cavitación acústica en el líquido, que es la formación, crecimiento e implosión de micro-burbujas que contienen gases disueltos y vapor de agua. El rápido colapso de las burbujas de cavitación es cercanamente adiabática. Por lo que cada burbuja funciona como un micro reactor en el cual se alcanzan temperaturas del orden de 5000K y presiones de cientos de atmosferas. Existen un varios factores que influyen en la generación ultrasónica como lo son la frecuencia del ultrasonido, el gas disuelto, el poder acústico y la temperatura aparente del liquido. Precursores para la preparación de la solución.

Barium (Ba) doping at Bismuth (Bi) site is reported to enhance magnetic properties of Bismuth Ferrite (BiFeO 3) while Yttrium (Y) doping at the same is found to improve ferroelectric and dielectric properties. To investigate the combined effect of Ba and Y co-doping, Ba 0.1 Bi 0.9-x Y x FeO 3 (x ¼ 0.0, 0.1 and 0.2) are synthesized using chemical synthesis route and their magnetoelectric and dielectric properties are studied in detail. The X-Ray Diffraction study confirms the single phase nature of the synthesized samples. The ferroelectric property is enhanced for x ¼ 0.1 while the magnetic studies show enhanced magnetisation for both co-doped samples with highest enhancement in x ¼ 0.1. The doped samples exhibit a first order field induced metamagnetic transition. The dielectric constant also increases with reduced tangent loss and conductivity for x ¼ 0.1. Therefore, co-doping with Ba and Y improves the magnetoelectric and dielectric property of BiFeO 3 .

- by Swarnali Hait
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- Multiferroics, Magnetoelectrics, Ferroelectrics, Ferroelectric materials

Unlike what is the case for physical entities and other types of continuants, few process ontologies exist. This is not only because processes received less attention in the research community, but also because classifying them is challenging. Moreover, upper level categories or classification criteria to help in modelling and integrating lower level process ontologies have thus far not been developed or widely adopted. This paper proposes a basis for further classifying processes in the Basic Formal Ontology. The work is inspired by the aspectual characteristics of verbs such as homeomericity, cumulativity, telicity, atomicity, instantaneity and durativity. But whereas these characteristics have been proposed by linguists and philosophers of language from a linguistic perspective with a focus on how matters are described, our focus is on what is the case in reality thus providing an ontological perspective. This was achieved by first investigating the applicability of these characteristics to the top-level processes in the Gene Ontology, and then, where possible, deriving from the linguistic perspective relationships that are faithful to the ontological principles adhered to by the Basic Formal Ontology.

- by Mustafa Jarrar
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- Bioinformatics, Ontology, Knowledge Management, Knowledge sharing
- by Barry Smith
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- Formal Ontology, Persistence, Geomatic Engineering, Upper Level Ontology

As part of a program to assess the adverse biological effects expected from astronaut exposure to space radiation, numerous different biological effects relating to astronaut health have been evaluated. There has been major focus recently on the assessment of risks related to exposure to solar particle event (SPE) radiation. The effects related to various types of space radiation exposure that have been evaluated are: gene expression changes (primarily associated with programmed cell death and extracellular matrix (ECM) remodeling), oxidative stress, gastrointestinal tract bacterial translocation and immune system activation, peripheral hematopoietic cell counts, emesis, blood coagulation, skin, behavior/fatigue (including social exploration, submaximal exercise treadmill and spontaneous locomotor activity), heart functions, alterations in biological endpoints related to astronaut vision problems (lumbar puncture/intracranial pressure, ocular ultrasound and histopathology studies), ...

- by Ann Kennedy
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- Medicine, SEM, Ct, PT

In product-diverse, end-of-life (EoL) production lines the relevant markets, competitors and customer bases continuously change as new products are processed. The resale market itself changes with the influx of new products, as well as hardware and software discontinuations. Competitive business decision making is often performed by a human operator and may not be timely or fully informed. These are decisions such as whether to perform a high cost repair or recycle a product or whether to use a batch of parts in repair or sell them on can be used to optimise product life-cycle management (PLM) and profit margins. A real-time decision making capability can reduce the risk of performing non-profitable processing. The novel contribution of this work is an interoperable semantic decision support toolset that is necessary to enable a capability for timely EoL decisions based on complete knowledge on profitability, predicted pricing and cost-of-production. Many decision support systems have been proposed for the EoL domain, but a lack of interoperability and use of unstructured knowledge bases has led to decisions based on knowledge that is not up to date. Using formalised, semantic technologies offers sustainable decision making in this volatile and increasingly competitive domain.

- by Richard P McClary
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- Architecture, Anatolian Archaeology, Islamic Art, Byzantine Architecture

Mobile charged defects, accumulated in the domain-wall region to screen polarization charges, have been proposed as the origin of the electrical conductivity at domain walls in ferroelectric materials. Despite theoretical and experimental efforts, this scenario has not been directly confirmed, leaving a gap in the understanding of the intriguing electrical properties of domain walls. Here, we provide atomic-scale chemical and structural analyses showing the accumulation of charged defects at domain walls in BiFeO3. The defects were identified as Fe(4+) cations and bismuth vacancies, revealing p-type hopping conduction at domain walls caused by the presence of electron holes associated with Fe(4+). In agreement with the p-type behaviour, we further show that the local domain-wall conductivity can be tailored by controlling the atmosphere during high-temperature annealing. This work has possible implications for engineering local conductivity in ferroelectrics and for devices based on domain walls.

- by Bob Young
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- Information Systems, Computer Science, Distributed Computing, Ontology
- by Xiaoding Qi
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- Materials Science, Multidisciplinary, Conductivity, BFO

Bio-inspired evolutionary algorithms are probabilistic search methods that mimic natural biological evolution. They show the behavior of the biological entities interacting locally with one another or with their environment to solve complex problems. This paper aims to analyze the most predominantly used bio-inspired optimization techniques that have been used for stock market prediction and hence present a comparative study between them.

- by Puspanjali Mohapatra
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- De, Pso, Evolutionary Computing, ACO

We developed a wavelength-tunable second harmonic scattering experimental setup to investigate dispersion of the nonlinear optical response of three different nanocrystal suspensions (LiNbO 3 , ZnO and BiFeO 3). Special attention was paid to reproducibility issues with the implementation of a detailed protocol that allows correcting for the setup spectral response. The absolute, orientation-averaged second order susceptibilities of the three nanomaterials were then assessed in the 700-1300 nm spectral range evidencing very specific optical signatures. The well-defined resonances observed for ZnO and BiFeO 3 near their electronic transitions were found to be poorly described by the Miller's rule.

- by Volodymyr Gayvoronsky
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- ZnO (Zinc Oxide), Second Harmonic Generation, BFO, Lithium Niobate