117 research outputs found

    Hydrogen peroxide production in an atmospheric pressure RF glow discharge: comparison of models and experiments

    Get PDF
    The production of (Formula presented.) in an atmospheric pressure RF glow discharge in helium-water vapor mixtures has been investigated as a function of plasma dissipated power, water concentration, gas flow (residence time) and power modulation of the plasma. (Formula presented.) concentrations up to 8 ppm in the gas phase and a maximum energy efficiency of 0.12 g/kWh are found. The experimental results are compared with a previously reported global chemical kinetics model and a one dimensional (1D) fluid model to investigate the chemical processes involved in (Formula presented.) production. An analytical balance of the main production and destruction mechanisms of (Formula presented.) is made which is refined by a comparison of the experimental data with a previously published global kinetic model and a 1D fluid model. In addition, the experiments are used to validate and refine the computational models. Accuracies of both model and experiment are discussed

    Distribución del 1-butanol y 2-butanol en los sistemas agua/n-octano y agua/Dodecil ´Sulfato de Sodio (SDS)/n-octano usando dinámica molecular. Parte II. Uso de las herramientas gmx-density y gmx-densmap

    Get PDF
    En este trabajo, la distribución de las moléculas de 1-butanol y 2-butanol en los sistemas agua/n-octano y agua/SDS/n-octano fue determinada usando las herramientas gmx-density y gmx-densmap del programa gromacs con la finalidad de complementar a nivel computacional el comportamiento experimental estos co-surfactantes cuando están localizados en la región interfacial de estos sistemas. Los modelos de energía potencial GROMOS53A6 y SPC fueron utilizados para describir a las moléculas de 1-butanol, 2-butanol, SDS y agua, respectivamente. Estos modelos fueron capaces de predecir las propiedades interfaciales del sistema agua/n-octano y el área por molécula del Dodecil Sulfato de Sodio en la interfaz agua/n-octano de forma consistente. Finalmente, los perfiles y mapas de densidad demuestran que las moléculas de alcohol y SDS coexisten en la región interfacial del sistema agua/n-octano favoreciendo la estabilidad de la monocapa de surfactante y la película interfacial

    NANOTECNOLOGÍA Y LA INDUSTRIA PETROLERA: APLICACIONES POTENCIALES EN EL ECUADOR

    Get PDF
    We consider some applications of nanotechnology to the oil industry worldwide and in particular we discuss some recent applications in Colombia. We consider some potential applications of nanotechnology to the oil industry in Ecuador and succinctly describe a project to design, synthesize, characterize and test nanostructure-based catalysts for the Ecuadorian oil industry. We discuss perspectives and difficulties related to these applications.Consideramos algunas aplicaciones de la nanotecnología a la industria petrolera a nivel mundial y discutimos, en particular, algunas aplicaciones recientes en Colombia.  Consideramos algunas aplicaciones potenciales de la nanotecnología en la industria petrolera del Ecuador y describimos en forma sucinta un proyecto para diseñar, sintetizar, caracterizar y probar catalizadores basados en nano estructuras para la industria petrolera ecuatoriana. Discutimos algunas perspectivas y dificultades relacionadas con estas aplicaciones

    The impact of control strategies and behavioural changes on the elimination of Ebola from Lofa County, Liberia.

    Get PDF
    The Ebola epidemic in West Africa was stopped by an enormous concerted effort of local communities and national and international organizations. It is not clear, however, how much the public health response and behavioural changes in affected communities, respectively, contributed to ending the outbreak. Here, we analyse the epidemic in Lofa County, Liberia, lasting from March to November 2014, by reporting a comprehensive time line of events and estimating the time-varying transmission intensity using a mathematical model of Ebola transmission. Model fits to the epidemic show an alternation of peaks and troughs in transmission, consistent with highly heterogeneous spread. This is combined with an overall decline in the reproduction number of Ebola transmission from early August, coinciding with an expansion of the local Ebola treatment centre. We estimate that healthcare seeking approximately doubled over the course of the outbreak, and that isolation of those seeking healthcare reduced their reproduction number by 62% (mean estimate, 95% credible interval (CI) 59-66). Both expansion of bed availability and improved healthcare seeking contributed to ending the epidemic, highlighting the importance of community engagement alongside clinical intervention.This article is part of the themed issue 'The 2013-2016 West African Ebola epidemic: data, decision-making and disease control'

    Harnessing photosynthetic microorganisms for enhanced bioremediation of microplastics: A comprehensive review

    Get PDF
    © 2024 The Authors. Published by Elsevier. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1016/j.ese.2024.100407Mismanaged plastics, upon entering the environment, undergo degradation through physicochemical and/or biological processes. This process often results in the formation of microplastics (MPs), the most prevalent form of plastic debris (<1 mm). MPs pose severe threats to aquatic and terrestrial ecosystems, necessitating innovative strategies for effective remediation. Some photosynthetic microorganisms can degrade MPs but there lacks a comprehensive review. Here we examine the specific role of photoautotrophic microorganisms in water and soil environments for the biodegradation of plastics, focussing on their unique ability to grow persistently on diverse polymers under sunlight. Notably, these cells utilise light and CO2 to produce valuable compounds such as carbohydrates, lipids, and proteins, showcasing their multifaceted environmental benefits. We address key scientific questions surrounding the utilisation of photosynthetic microorganisms for MPs and nanoplastics (NPs) bioremediation, discussing potential engineering strategies for enhanced efficacy. Our review highlights the significance of alternative biomaterials and the exploration of strains expressing enzymes, such as polyethylene terephthalate (PET) hydrolases, in conjunction with microalgal and/or cyanobacterial metabolisms. Furthermore, we delve into the promising potential of photo-biocatalytic approaches, emphasising the coupling of plastic debris degradation with sunlight exposure. The integration of microalgal-bacterial consortia is explored for biotechnological applications against MPs and NPs pollution, showcasing the synergistic effects in wastewater treatment through the absorption of nitrogen, heavy metals, phosphorous, and carbon. In conclusion, this review provides a comprehensive overview of the current state of research on the use of photoautotrophic cells for plastic bioremediation. It underscores the need for continued investigation into the engineering of these microorganisms and the development of innovative approaches to tackle the global issue of plastic pollution in aquatic and terrestrial ecosystems.The authors acknowledge the financial support by the University of Graz (Open Access Publishing Agreement). ARS would like to acknowledge the support given through ED431C2021/46-GRC attributed to Universidade de Vigo by Xunta de Galicia and IJC2020-044197-I through the Universidade de Vigo, MCIN/AEI/ 10.13039/501100011033 and the European Union through “Next- GenerationEU/PRTR”. This article/publication is based upon work from COST Action CA20101 Plastics monitoRIng detectiOn RemedIaTion recoverY - PRIORITY, supported by COST (European Cooperation in Science and Technology), www.cost.eu. This work was partially supported the University of Wolverhampton Research Investment Fund (RIF4).Accepted versio

    Plasma-liquid interactions: a review and roadmap

    Get PDF
    Plasma-liquid interactions represent a growing interdisciplinary area of research involving plasma science, fluid dynamics, heat and mass transfer, photolysis, multiphase chemistry and aerosol science. This review provides an assessment of the state-of-the-art of this multidisciplinary area and identifies the key research challenges. The developments in diagnostics, modeling and further extensions of cross section and reaction rate databases that are necessary to address these challenges are discussed. The review focusses on non-equilibrium plasmas

    The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2

    Get PDF
    Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase&nbsp;1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation&nbsp;disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age&nbsp; 6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score&nbsp; 652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc&nbsp;= 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N&nbsp;= 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in&nbsp;Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in&nbsp;Asia&nbsp;and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701

    Mecánica cuántica: postulados

    No full text
    The microscopic world is fully described by the quantum mechanics and P.A.M. Dirac uses the basic elements of linear algebra to do so. In this work the postulates of quantum mechanics are presented using vector spaces and quantum operators.La Mecánica Cuántica describe de una manera completa el mundo microscópico, y para esto el físico británico P.A.M. Dirac hace uso de&nbsp; los&nbsp; elementos&nbsp; básicos&nbsp; del&nbsp; álgebra&nbsp; lineal&nbsp; para&nbsp; lograrlo.&nbsp; Este&nbsp; trabajo&nbsp; da&nbsp; a&nbsp; conocer&nbsp; los&nbsp; postulados&nbsp; fundamentales&nbsp; de&nbsp; la&nbsp; mecánica&nbsp; cuántica haciendo uso de los espacios vectoriales y operadores cuánticos.&nbsp

    Modelando el transporte de iones de potasio a través de un canal iónico de una membrana celular

    No full text
    Conduction models of ion through voltage-gated ion channels, at symmetrical concentration in cellular membrane, have been developed. These channels are highly selective to K or Na ions due to a potential difference. First, it is considered the theory of metallic conduction, where, it is assumed a random distribution of obstacles, which oppose to free motion of ions inside the channel. This spacing distribution among obstacles turned out to be very narrow and its mean value is very small, that implies an almost continuous collision of ion with the channel obstacles. In addition, a model based on the crystal periodic structure is proposed. These models would describe the experimental values of conduction, but the parameters associated to each model would take values that are not easy to verify experimentally, and they are related to the channel structure.&nbsp;&nbsp;Se desarrolla dos modelos de conducción de iones a través de una membrana celular en condiciones simétricas de concentración considerando canales iónicos activados por voltaje. Estos canales son altamente selectivos a iones K o Na en presencia de una diferencia de potencial. Primero se plantea un modelo de conducción similar al de la conducción de electrones libres en metales donde se modela una distribución aleatoria de obstáculos que impiden el movimiento libre del ion dentro del canal. Esta distribución de espaciamiento entre obstáculos resultó ser muy angosta y su valor medio muy pequeño, implicando un casi continuo choque del ion con los obstáculos presentes en el canal. Adicionalmente, se propone un modelo considerando al canal como una estructura periódica. Para que estos modelos describan los valores experimentales de conducción, los parámetros asociados a cada modelo tienen valores que no son fáciles de comprobar experimentalmente los cuales tienen relación con la estructura del canal.&nbsp
    corecore