Radiative Transference Equation Algorithm as an ANSYS® User-Defined Function for Solar Technology Applications

Heat effects in photocatalytic reactor applications are discussed and a case study is analyzed where sunlight is used to activate a chemical reaction to degrade water pollutants. Heat is produced in the light-capturing process, and heat effects need to be better understood during the device design process. Radiative transfer equation (RTE) is the guiding equation used to calculate radiation proliferation in participating media, and it is used to describe the balance of radiative energy transport in the participating media including the interactions caused by different processes such as absorption, scattering, and emission, which also are subject to additional phenomena like weakening and magnification. This equation plays an important role in the design process since it may be included in the simulation process to represent the sunlight heat effects in the different photocatalytic reactor components. In this chapter, it is explained how to build a simplified algorithm to incorporate the RTE in a numerical calculation during the design of a photocatalytic reactor using the commercial software ANSYS®. In addition, simplifications are explained that enable the program to coordinate some coefficients such as absorption and dispersion so their effects are included within the numerical calculation. A user-defined function is presented in the end of the chapter as a usable algorithm in ANSYS® program with acceptable results for photocatalytic reactors

Excited States of Six Anthocyanidin Variants with Different Solvents as Dye Sensitizers for Photocatalysis

Anthocyanidins in the gas phase and under the effects of solvents such as water, ethanol, n-hexane, and methanol have been studied using DFT and TDDFT electronic structure calculations for applications as natural dyes in photocatalysis. The results include HOMO and LUMO orbitals, HOMO-LUMO gap, chemical properties, reorganization energies, and excited states. Malvidin presented the lower HOMO-LUMO gap energy. After the inclusion of solvents, HOMO-LUMO gap energy increased in all cases, presenting malvidin with n-hexane as the narrower gap energy. Conceptual DFT results showed that cyanidin, malvidin, and pelargonidin present good charge transfer properties. Cyanidin presented a lower electron reorganization energy (λe) when water is used as the solvent. TDDFT has been used for excited states calculation and absorption data show the main peaks in a wavelength between 479.1 and 536.4 nm. The UV–Vis absorption spectra were generated and the solvent effects in each case are discussed. In consequence, pigments selected in this attempt are suitable to work in the visible part of the electromagnetic spectrum and display the main peak in the green region. These pigments are found as good options for photocatalysis applications, and the best choices for dye sensitization are cyanidin, malvidin, and petunidin after including the more common anthocyanidins in the analysis

Hydrodynamic Analysis on a Photocatalytic Reactor Using ANSYS Fluent^®

Solar technology includes a wide variety of developments in environmental applications that include photovoltaic cells and photocatalytic devices, among others. Sunlight usage as a clean energy source is highly desirable in technology applications. The main interest of this proposal is to carry on with hydrodynamic analysis in photocatalytic reactors applications where sunlight is used to activate a chemical reaction to degrade water pollutants and calculations are based in computational fluid dynamics (CFD) using ANSYS®. The different steps, geometric domain, preprocessing steps, setup, and postprocessing steps, are described to display an analysis of a numerical calculation during the design of a photocatalytic reactor using the commercial software ANSYS Fluent®. This work may help as a guide for chemical reactor design and includes a numerical solution of one case for a photocatalytic reactor during its design process. In addition, simplifications are explained which enable the designer to make an efficient process of the numerical calculation. Calculations and analysis are carried over in ANSYS Fluent® a powerful multi-physics program suite to develop photocatalytic reactors

Solvent Effects on Dye Sensitizers Derived from Anthocyanidins for Applications in Photocatalysis

Anthocyanidins under the effects of solvents water, ethanol, n-hexane, and methanol are interesting due to their suitability as natural dyes for photocatalytic applications. In this chapter, DFT and TDDFT methodologies are used to study their electronic structure. The results displayed include HOMO, LUMO, HOMO-LUMO gap, chemical properties, and reorganization energies for the ground states, and excited state data are also displayed. Malvidin in gas phase has lower gap energy. After addition of solvents, gap energy increases in all cases but malvidin with n-hexane presents narrower gap. Conceptual DFT results show that cyanidin and malvidin may have good charge transfer. Cyanidin presented lower electron reorganization energy (λe) using solvent water; however, ethanol and methanol had similar values. TDDFT is used to calculate excited states, and absorption data show wavelength main peak between 479.1 and 536.4 nm. UV-Vis absorption spectra were generated and solvent effects on each molecule is discussed. Anthocyanidins work well in the visible region with the stronger peak at the green region. These pigments are good options for photocatalysis application and cyanidin and malvidin, in this order, may be the best choices for dye sensitization applications

Caracterización de la calidad ecológica del bosque de galería del río La Sauceda, Durango, México

Due to the level of reliability of information that can be obtained, as well as the simplicity and speed in implementation and because of its low cost, a quality index for riparian forests (QBR) was applied in order to characterize the ecological status of the riparian forest associated with the La Sauceda River, in Durango, Mexico. It is one of the major rivers in the San Pedro-Mezquital River basin, the most important source of fresh water for the National Wetlands Biosphere Reserve, a red focus on the conservation of Mexican biodiversity, since it is the mangroves largest and production in North America. The La Sauceda River faces major threats from plans to construct large dams and remove gallery forests. Results from this study showed a forest in poor ecological condition, demonstrating that the index is a reliable tool for hydromorphological diagnosis of rivers and riverbanks.Debido al nivel de confiabilidad de la información que se puede obtener, así como la sencillez y rapidez en su aplicación además de su bajo costo, se aplicó el índice de Calidad del Bosque de Ribera (QBR) con el fin de caracterizar el estado ecológico que guarda el bosque de ribera asociado al río La Sauceda, Durango, México. Éste es uno de los principales ríos de la cuenca del río San Pedro-Mezquital, el mayor abastecedor de agua dulce a la Reserva de la Biosfera Marismas Nacionales, un foco rojo en la conservación de la biodiversidad mexicana, ya que es la zona de manglar más grande y productiva de Norteamérica. Los planes de construcción de grandes presas y la eliminación del bosque de galería debido a la extensión de la frontera agrícola, son algunas de las principales amenazas del río la Sauceda. Los resultados indican un bosque en malas condiciones ecológicas, mostrando que el índice es una herramienta que contribuye a la diagnosis hidromorfológica de ríos y riberas

Gestión del conocimiento. Perspectiva multidisciplinaria. Volumen 17

El libro “Gestión del Conocimiento. Perspectiva Multidisciplinaria”, Volumen 17 de la Colección Unión Global, es resultado de investigaciones. Los capítulos del libro, son resultados de investigaciones desarrolladas por sus autores. El libro es una publicación internacional, seriada, continua, arbitrada, de acceso abierto a todas las áreas del conocimiento, orientada a contribuir con procesos de gestión del conocimiento científico, tecnológico y humanístico. Con esta colección, se aspira contribuir con el cultivo, la comprensión, la recopilación y la apropiación social del conocimiento en cuanto a patrimonio intangible de la humanidad, con el propósito de hacer aportes con la transformación de las relaciones socioculturales que sustentan la construcción social de los saberes y su reconocimiento como bien público

Perspectives of Organic Dyes Cosensitization and Its Utilization in TiO₂ Nanoclusters for Photocatalysis Applications

Cosensitization has emerged as a method to improve performance of dye sensitized solar cells (DSSCs) and photocatalysis. In this work, it is proposed to use organic dyes as cosensitizers due to their friendliness with the environment and to the benefits of having two or more different dyes with complementary optical absorption characteristics. Several organic dyes are analyzed as cosensitizers to identify which dye combinations may be good choices to approach a panchromatic absorption spectrum emulating the solar emission spectrum. In addition to the analysis on the prospective sensitizers, it is presented results of titanium dioxide (TiO2) nanoclusters cosensitized with two anthocyanidins using density functional theory (DFT) and time-dependent DFT (TD-DFT). The nanocluster size proved to be definitive in the interactions with two molecule dyes. The selected (TiO2)4–5 nanoclusters cosensitized with two anthocyanidins produce data for a prospective analysis to suggest which dyes are good options for DSSCs and photocatalysis based on dye co-sensitization applications. At the end, one can look at this work as a perspective of which organic dyes may work well as cosensitizers and a contrast to original data from our experimentation with a couple of TiO2 nanoclusters cosensitized with two different anthocyanidins

A Lineage of Begomoviruses Encode Rep and AC4 Proteins of Enigmatic Ancestry: Hints on the Evolution of Geminiviruses in the New World

The begomoviruses (BGVs) are plant pathogens that evolved in the Old World during the Cretaceous and arrived to the New World (NW) in the Cenozoic era. A subgroup of NW BGVs, the “Squash leaf curl virus (SLCV) lineage” (S-Lin), includes viruses with unique characteristics. To get clues on the evolutionary origin of this lineage, a search for divergent members was undertaken. Four novel BGVs were characterized, including one that is basal to the group. Comparative analyses led to discover a ~670 bp genome module that is nearly exclusive of this lineage, encompassing the replication origin, the AC4 gene, and 480 bp of the Rep gene. A similar DNA module was found in two curtoviruses, hence suggesting that the S-Lin ancestor acquired its distinctive genomic segment by recombination with a curtovirus. This hypothesis was definitely disproved by an in-depth sequence analysis. The search for homologs of S-Lin Rep uncover the common origin of Rep proteins encoded by diverse Geminiviridae genera and viral “fossils” integrated at plant genomes. In contrast, no homolog of S-Lin Rep was found in public databases. Consequently, it was concluded that the SLCV clade ancestor evolved by a recombination event between a primitive NW BGV and a virus from a hitherto unknown lineage

A CFD Porous Materials Model to Test Soil Enriched with Nanostructured Zeolite Using ANSYS-Fluent⁽™⁾

Soil health is a great concern worldwide due to the huge variety of pollutants and human activities that may cause damage. There are different ways to remediate and make a better use of soil and a choice may be using zeolite in activities like gardening, farming, environment amending, among others. In this work is proposed a model to simulate how mixing zeolite with soil may be beneficial in different ways, we are especially interested in interactions of mixed soil-zeolite with water. This model is based in different flow regimes where water interacts with two layers formed by nanostructured zeolite and soil in a vertical arrangement. The analysis is approached as a bi-layer porous material model resolved by using the mathematical model implemented in ANSYS-Fluent. Such model uses a multi-fluid granular model to describe the flow behavior of a fluid–solid mixture where all the available interphase exchange coefficient models are empirically based. Despite the great capabilities of numerical simulation tools, it is known that at present time, the literature lacks a generalized formulation specific to resolve this kind of phenomena where a porous media is analyzed. This model is developed to obtain a systematic methodology to test nanomaterials with porous features produced in our laboratory which is the next step for near future work within our research group