Process simulation and optimization of H-2 production from ethanol steam reforming and its use in fuel cells. 2 : Process analysis and optimization

The feasibility of power cogeneration through fuel cells using bioethanol with different concentration has been considered. Data and layout have been inspired by an existing unit Helbio, GH2-BE-5000 (5 kW(electrical) + 5 kW(thermal)) system for combined heat and power generation (CHP). The system is constituted by six reactors connected in series for hydrogen production and purification and by a fuel cell of the mentioned capacity. To evaluate process efficiency and the possibility to operate with diluted bioethanol feed, characterized by lower purification cost, different process layouts have been tested. Particular attention is paid to the intensification of the heat exchange network, to increase the overall plant efficiency. Heat supply to the steam reformer has been accomplished by burning part of the reformate, since diluted ethanol is not suitable to feed the burner as in the experimental process layout. The water/ethanol feeding ratio has been taken as major parameter for simulation. An increase of this variable improved H-2 yield due to promotion of the water gas shift reaction and lower impact of the hydrogen-consuming methanation step. However, higher heat input was required by the reformer, implying the delivery of a higher fraction of the reformate to the burner instead than to the fuel cell. This means lower electric output and efficiency. However, the presence of a high enthalpy steam exhaust increased the available thermal output, with consequent increase of the thermal and overall efficiency of the plant

Antioxidant effect of lutein protects against oxidative damage to porcine spermatozoa

<p Boar sperm is especially susceptible to peroxidative damage generated by reactive oxygen species (ROS). Chemiluminescence was initiated by incubating porcine semen in an in vitro ascorbate-Fe++ system, a technique that allows the evaluation of oxidative stress in these cells. Lutein is known for its antioxidant effects, chemically it is a dihydric derivative of α-carotene and belongs to the group of xanthophylls. The main objective of this study was to investigate the antioxidant effect of lutein on boar spermatozoa. The effect of lutein was analyzed by two methods: 1) by adding lutein: the sperm samples were placed in an in vitro ascorbate- Fe++ system, during 120 min at 37°C adding increasing amounts of lutein (50, 150 and 250 μg) per mg of protein and 2) by incubation with lutein in an in vitro ascorbate-Fe+2 system, for 120 min at 37°C, using spermatozoa obtained from porcine semen samples previously incubated with lutein (0.15 and 0.25 mg/ml) during 24 h at 15°C. In both methods a control group (without lutein) was used. Peroxidation was measured by chemiluminescence using a liquid scintillation counter, the light emission being quantified in cpm (counts per minute). Analyzing the effect of lutein by the two methods, it was observed that the total amount of cpm/mg of protein originated by chemiluminescence was lower in samples obtained from the lutein group than in the control group (without lutein). Total chemiluminescence (cpm total) was lower in samples obtained from the lutein group than in the control group (without lutein), with a significance of p<0.005. Percent inhibition of peroxidation was not concentration dependent. These results would demonstrate that lutein could act as an antioxidant that would protect the membranes of the sperm from oxidative damage.p>Boar sperm is especially susceptible to peroxidative damage generated by reactive oxygen species (ROS). Chemiluminescence was initiated by incubating porcine semen in an in vitro ascorbate-Fe++ system, a technique that allows the evaluation of oxidative stress in these cells. Lutein is known for its antioxidant effects, chemically it is a dihydric derivative of α-carotene and belongs to the group of xanthophylls. The main objective of this study was to investigate the antioxidant effect of lutein on boar spermatozoa. The effect of lutein was analyzed by two methods: 1) by adding lutein: the sperm samples were placed in an in vitro ascorbate-Fe++ system, during 120 min at 37°C adding increasing amounts of lutein (50, 150 and 250 μg) per mg of protein and 2) by incubation with lutein in an in vitro ascorbate-Fe+2 system, for 120 min at 37°C, using spermatozoa obtained from porcine semen samples previously incubated with lutein (0.15 and 0.25 mg/ml) during 24 h at 15°C. In both methods a control group (without lutein) was used. Peroxidation was measured by chemiluminescence using a liquid scintillation counter, the light emission being quantified in cpm (counts per minute). Analyzing the effect of lutein by the two methods, it was observed that the total amount of cpm/mg of protein originated by chemiluminescence was lower in samples obtained from the lutein group than in the control group (without lutein). Total chemiluminescence (cpm total) was lower in samples obtained from the lutein group than in the control group (without lutein), with a significance of p<0.005. Percent inhibition of peroxidation was not concentration dependent. These results would demonstrate that lutein could act as an antioxidant that would protect the membranes of the sperm from oxidative damage

CATALYTIC AND PHOTOCATALYTIC PROCESSES FOR THE PRODUCTION OF ALTERNATIVE FUELS AND CHEMICALS FROM RENEWABLE SOURCES

The research project during my three years of activity was focused on the de-velopment of innovative processes and catalytic materials for the production of sustainable chemicals and fuels. The work was mainly divided in three are-as: i) bioethanol valorization through the heterogeneous catalytic production of H2 and ethylene; ii) CO and CO2 conversion; iii) H2 usage through ammonia production

Alternativa metodológica para la enseñanza obligatoria de "Ecología y medio ambiente" en Arquitectura

Este trabajo tiene como objetivo principal presentar el desarrollo de una experiencia pedagógica que incorpora a la enseñanza de grado del futuro arquitecto la temática del medio ambiente, respondiendo a la inquietud de la U.A.I. por proponer un perfil profesional de arquitecto consciente de su interacción con el medio y del carácter de soporte estructural que adquiere éste para sus proyectos. Esta asignatura tiene carácter obligatorio y pretende otorgar al alumno las herramientas básicas para la interpretación del contexto medioambiental donde debe operar. El programa, respondiendo a la propuesta de la universidad de organizar los contenidos en base a unidades problemáticas, plantea las unidades siguiendo una coherencia desde la generalidad de una instancia más conceptual en términos ecológicos, hasta la introducción en criterios básicos para la práctica del diseño bioambiental. La experiencia, permitió verificar el cumplimiento de los objetivos y hacer una revisión que apunta a la incorporación de trabajos de investigación de cátedra en el desarrollo de la cursada.The main objective of this paper is to present a pedagogic experience development that includes environmental topics in university education of futures architects. It is an answer to the U.A.I idea to propose an architect professional profile conscious of his interaction with the environment and of its structural support meaning for architectural projects . This is an obligatory subject in this university and pretends to provide the students basic tools to identify the environmental context where they must operate. This programme responds to the university propose to organise its contents based in troubled situations and introduce this units following a coherency since a conceptual stage in ecological terms, up to the introduction in basic strategies for a bioambiental design practice. The work developed allowed to carry out the objectives and a revision that includes the students studies.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Alternativa metodológica para la enseñanza obligatoria de "Ecología y medio ambiente" en Arquitectura

Este trabajo tiene como objetivo principal presentar el desarrollo de una experiencia pedagógica que incorpora a la enseñanza de grado del futuro arquitecto la temática del medio ambiente, respondiendo a la inquietud de la U.A.I. por proponer un perfil profesional de arquitecto consciente de su interacción con el medio y del carácter de soporte estructural que adquiere éste para sus proyectos. Esta asignatura tiene carácter obligatorio y pretende otorgar al alumno las herramientas básicas para la interpretación del contexto medioambiental donde debe operar. El programa, respondiendo a la propuesta de la universidad de organizar los contenidos en base a unidades problemáticas, plantea las unidades siguiendo una coherencia desde la generalidad de una instancia más conceptual en términos ecológicos, hasta la introducción en criterios básicos para la práctica del diseño bioambiental. La experiencia, permitió verificar el cumplimiento de los objetivos y hacer una revisión que apunta a la incorporación de trabajos de investigación de cátedra en el desarrollo de la cursada.The main objective of this paper is to present a pedagogic experience development that includes environmental topics in university education of futures architects. It is an answer to the U.A.I idea to propose an architect professional profile conscious of his interaction with the environment and of its structural support meaning for architectural projects . This is an obligatory subject in this university and pretends to provide the students basic tools to identify the environmental context where they must operate. This programme responds to the university propose to organise its contents based in troubled situations and introduce this units following a coherency since a conceptual stage in ecological terms, up to the introduction in basic strategies for a bioambiental design practice. The work developed allowed to carry out the objectives and a revision that includes the students studies.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Alternativa metodológica para la enseñanza obligatoria de "Ecología y medio ambiente" en Arquitectura

Este trabajo tiene como objetivo principal presentar el desarrollo de una experiencia pedagógica que incorpora a la enseñanza de grado del futuro arquitecto la temática del medio ambiente, respondiendo a la inquietud de la U.A.I. por proponer un perfil profesional de arquitecto consciente de su interacción con el medio y del carácter de soporte estructural que adquiere éste para sus proyectos. Esta asignatura tiene carácter obligatorio y pretende otorgar al alumno las herramientas básicas para la interpretación del contexto medioambiental donde debe operar. El programa, respondiendo a la propuesta de la universidad de organizar los contenidos en base a unidades problemáticas, plantea las unidades siguiendo una coherencia desde la generalidad de una instancia más conceptual en términos ecológicos, hasta la introducción en criterios básicos para la práctica del diseño bioambiental. La experiencia, permitió verificar el cumplimiento de los objetivos y hacer una revisión que apunta a la incorporación de trabajos de investigación de cátedra en el desarrollo de la cursada.The main objective of this paper is to present a pedagogic experience development that includes environmental topics in university education of futures architects. It is an answer to the U.A.I idea to propose an architect professional profile conscious of his interaction with the environment and of its structural support meaning for architectural projects . This is an obligatory subject in this university and pretends to provide the students basic tools to identify the environmental context where they must operate. This programme responds to the university propose to organise its contents based in troubled situations and introduce this units following a coherency since a conceptual stage in ecological terms, up to the introduction in basic strategies for a bioambiental design practice. The work developed allowed to carry out the objectives and a revision that includes the students studies.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Time Dynamics of the Down-Coupling Phenomenon in 3-D NAND Strings

We present a detailed analysis of the time dynamics of the down-coupling phenomenon (DCP) in 3-D NAND Flash memory strings. The transient time dynamics of the channel potential following the wordline (WL) bias transition fromthe pass voltage to zero is studied via numerical simulation, highlighting the existence of three temporal regimes controlledby different physical processes: electron emission from traps, hole injection from the string edges followed by capture, and propagation along the string. The impact of these processes is separately studied, followed by an analysis of the dependence of the DCP recovery time on architectural parameters. Results highlight the relevant physics and can be used as a design guideline for NAND strings with reduced sensitivity to the DCP