A comparative study of the characteristics and physical behaviour of different packing materials commonly used in biofiltration

In this study, the characteristics and physical behaviour of 8 different packing materials were compared. The materials were selected according to previous works in the field of biofiltration including organic and inorganic or synthetic materials. Results pre-selected those more acceptable support materials for the main function they have to perform in the biological system: high surface contact, rugosity to immobilize the biomass, low pressure drop, nutrients supply, water retentivity or a commitment among them. Otherwise, pressure drop have been described by means of the respective mathematic expressions in order to include phenomena in the classical biofiltration models.Peer ReviewedPostprint (author's final draft

Propuesta de un modelo de migración de un sistema gestión de la calidad ISO 9001:2008 a un sistema de gestión de la calidad basado en la estructura de alto nivel, ISO/DIS 9001:2015

En un mundo cambiante y una economía variable a nivel nacional e internacional, en donde cada vez las grandes compañías multinacionales intenten ingresar e inundar los mercados naciones con sus productos a bajos precios debido a sus bajos costos operacionales y capacidad operativa, además con la creación de nuevos tratados de comercio, con países cuya economía es superior a la nuestra(Estados Unidos, china) lo que les da una ventaja considerable a esta grandes compañías; ahora las grandes y las pequeñas empresas nacionales, se verán considerablemente afectadas y por ende a desaparecer por lo que tiene que apostarle todo a su gran objetivo satisfacer el cliente, tanto nacional como internacional para permanecer en el mercado, estas empresas deben entrar a competir con sus productos, por lo que se deben dar a la tarea de buscar nuevas estrategias que le permitan sobrevivir en el medio y expandir sus mercados, una de esas estrategias es la reducción de costos de operación (producción, almacenamiento y el producto no conforme), y conservar siempre los estándares de calidad a nivel internacional, para apoyarse en este propósito muchas organizaciones han empezado a adoptar modelos de gestión de la calidad con bases en normativas internaciones ISO, buscando el mejoramiento continuo de sus operaciones tanto internas como externas y aumentar sus ventajas competitivas; ahora que se acercan nuevos cambios en algunos modelos de gestión de la calidad como es la ISO 9001:2008, por lo que las organizaciones deberán implementar y ajustar sus modelos de gestión para migrar hacia la nueva versión y acoplarse a los cambios que ésta traiga los cuales permitirá a las organizaciones aumentar y mejorar la calidad de sus productos y servicios ya que le permitirá a las organizaciones llevar sus sistema de calidad a una estructura de alto nivel y por ende mejorar el control sobre sus procesos y las relaciones con sus stakeholders, estas mejoras favorecerá tanto a las organización como a la economía y la sociedad colombiana

Bibliometric analysis of the literature on critical thinking: an increasingly important competence for higher education students

In recent years, interest in critical thinking(CT) has grown considerably. An evaluation of this research field and its challenges are provided in this paper. A bibliometric study was performed to analyse 1,295 papers on CT published in the last 50 years. The data were obtained from the WOS Core Collection database. The findings of this study improve the understanding of the CT domain by showing key studies, the main studies developing the field, key past studies and their influence in subsequent publications, emerging trends and potentially transformative ideas. Most publications and citations are from the last decade, reflecting the momentum of this concept over the period examined. The topic has also expanded geographically. Although the University of Iowa and the University of Alberta are the most prolific institutions, Asian universities have gained in prominence in recent years, as shown by the number of papers published. According to the analysis, the increase in the number of authors, publications and journals in this field and the rise in the number of publications written in collaboration with authors from different parts of the world are two trends that reflect the interest in CT as a way to understand the development of thinking skills

Nuevos documentos hebraico-aljamiados de Aragón (1). Fragmentos de un registro contable de pagos de la aljama de Tarazona

Preliminary study and transcription of the surviving fragments of an expenditures' register of the Jewish community of Tarazona (1406-1407). The forty-two entries written in Aragonese aljamía deal with payments implemented by communal officers on different issues: fiscal disbursements, communal defence expenses and public debt, trial and execution of an informer, religious expenses (maintenance of buildings and charity institutions, officers' salaries, and payment of the Sukkot arba‘ah minim). Especially relevant are the references to dependence relations regarding the Saragossa Jewish community.Estudio introductorio con transcripción de los fragmentos de un registro contable de 1406 y 1407 de los pagos de la aljama de Tarazona (Aragón). Los cuarenta y dos cargos anotados en aljamía romance aragonesa, que incluye interesantes detalles léxicos, proporcionan información acerca de pagos realizados por oficiales de la aljama sobre asuntos diversos: fiscalidad y gastos de defensa de la aljama, su endeudamiento, el proceso y la ejecución de un malsín, gastos de sus instituciones religiosas y de asistencia social, sueldos de oficiales y pago por la aljama de las «cuatro especies» utilizadas en Sucot. Especialmente importantes son las referencias a la relación de dependencia respecto de la judería de Zaragoza

Conversion of chemical scrubbers to biotrickling filters for VOCs and H2S treatment at low contact times

The purpose of this work was to evaluate the technical and economical feasibility of converting three chemical scrubbers in series to biotrickling filters (BTFs) for the simultaneous removal of H2S and volatile organic compounds (VOCs). The conversion of the full-scale scrubbers was based on previous conversion protocols. Conversion mainly required replacing the original carrier material and recycle pumps as well as modifying the controls and operation of the reactors. Complete removal of H2S and VOCs on a routine basis was reached at neutral pH in a longer period of time compared to previous conversions reported. Biotrickling filters operated at a gas contact time of about 1.4 s per reactor and at pH controlled between 6.5 and 6.8. Inlet average concentrations below 10 ppmv of H2S and below 5 ppmv for VOCs were often completely removed. The first and second bioreactors played a primary role in H2S removal. Year-round operation of the biotrickling filters proved the ability of the system to handle progressive load increases of H2S and VOCs. However, fast, sudden load changes often lead to reduced removal efficiencies. Odor analyses showed average removal efficiencies above 80 %. Gas chromatography-mass spectrometry of selected samples showed that outlet odor concentration was due to limited removal of VOCs. The conversion showed was economically viable taking into account the theoretical consumption of chemicals needed for the absorption and oxidation of both H2S and VOCs.Peer ReviewedPostprint (published version