Development of a Passive Mini-Direct Ethanol Fuel Cell: Effect of Mea Assembly Parameters by Hot Pressure

This paper presents preliminary results on the design, construction and evaluation of a passive mini direct ethanol fuel cell (DEFC), capillary fed with 2 mol l-1 aqueous ethanol, at a rate of 2.03 μL min-1, and air oxygen in the cathode through an air vent. Parameters such as pressure, temperature and time of manufacturing a membrane-electrode assembly (MEA) by hot-pressure were evaluated. As the electrode holder used a 0.25 cm2 carbon tissue which was deposited on the catalytic layer (C. L.) for both the anode (0.8 mg cm-2of PtRu/C) and the cathode (0.8 mg cm -2of Pt/C), Nafi on® 115 membranes were used as the electrolyte. The results show, an average power density of 302 μWcm2 under the best conditions used, a catalytic layer with a Nafi on percentage of 50% at 25 °C. A temperature of 125 °C, a pressure of 49.2 Kg/cm2, and 90 seconds duration were used to obtain the MEA

Development of a passive mini-direct ethanol fuel cell : effect of mea assembly parameters by hot pressure.

This paper presents preliminary results on the design, construction and evaluation of a passive mini direct ethanol fuel cell (DEFC), capillary fed with 2 mol l-1 aqueous ethanol, at a rate of 2.03 μL min-1, and air oxygen in the cathode through an air vent. Parameters such as pressure, temperature and time of manufacturing a membrane-electrode assembly (MEA) by hot-pressure were evaluated. As the electrode holder used a 0.25 cm2 carbon tissue which was deposited on the catalytic layer (C. L.) for both the anode (0.8 mg cm-2 of PtRu/C) and the cathode (0.8 mg cm-2 of Pt/C), Nafi on® 115 membranes were used as the electrolyte. The results show, an average power density of 302 μWcm2 under the best conditions used, a catalytic layer with a Nafi on percentage of 50% at 25 °C. A temperature of 125 °C, a pressure of 49.2 Kg/cm2, and 90 seconds duration were used to obtain the MEA

METODOLOGÍA DE SELECCIÓN DE POZOS CANDIDATOS PARA TRATAMIENTOS DE CONFORMANCE QUÍMICO

La canalización generalmente es consecuencia de la heterogeneidad del yacimiento, especialmente por grandes variaciones de permeabilidad, ocasionando reducción en la eficiencia volumétrica como producto de la recirculación del fluido inyectado en procesos de recobro secundario y/o mejorado (EOR). Con el objetivo de mejorar el perfil vertical de inyección y reducir la recirculación de agua inyectada, en Colombia se han implementado, desde el año 2008 a 2020, 33 tratamientos de control de canalización y conformance químico profundo en nueve campos con el objetivo de aumentar la eficiencia de barrido volumétrico para incrementar el factor de recuperación de petróleo. El resultado de los tratamientos reportados es de hasta 3 barriles de petróleo incremental por cada barril de gel rígido inyectado. Sin embargo, la cantidad de tratamientos de conformance es baja en comparación con el número de pozos inyectores en el país de aproximadamente 1400). Por lo tanto, Ecopetrol adaptó una metodología de selección de pozos candidatos para tratamientos de conformance químico que tiene en cuenta continuidad de los yacimientos, determinación y caracterización de la heterogeneidad, estudio de movimiento de fluidos, determinación de conectividad del patrón de inyección, distribución vertical y areal de los fluidos inyectados y producidos, generación de gráficos diagnósticos en software Sahara para finalmente identificar los pozos candidatos y realizar el diseño del tratamiento de conformance. La generación de los gráficos diagnóstico base de la metodología tiene como punto de partida la distribución vertical de producción secundaria realizada por el método IWR de alocación de producciones de malla ponderando caudales, en el cual la producción de un pozo es distribuida entre los inyectores que lo afectan, y esta producción es asociada a cada inyector. Con respecto a la distribución areal se toman elementos de flujo creando mallas dinámicas centradas en inyector y se pondera utilizando la distribución angular. La distribución de producción secundaria tiene en cuenta los ILT/PLT realizados históricamente en los pozos inyectores/ productores, mallado y coeficientes de distribución de los patrones de inyección en el tiempo. En el presente trabajo se hace una descripción y aplicación de la metodología integrada que permite identificar la producción de petróleo y agua por yacimiento en cada patrón de inyección, así como la eficiencia del agua inyectada para mapear acciones de mejoramiento de la producción de petróleo y disminución de la producción de agua, con el objetivo de identificar los sectores con menor desempeño y que requieren optimización del proceso secundario y/o mejorado. La metodología se validó y complementó con información de trazadores interwell (IWTT) y simulación numérica en líneas de flujo (streamline). En ese sentido, se vienen aplicando tratamientos de conformance desde el año 2021 en 23 nuevos pozos con resultados prometedores de producción incremental de petróleo. La selección de pozos candidatos para tratamientos de conformance químico amplían las expectativas de masificación de estas tecnologías en diferentes campos del país y se convierten en pieza fundamental para apalancar la consecución de reservas y una disminución de la huella de carbono debido principalmente a que con el mismo caudal de fluido inyectado se incrementa la producción de petróleo y en algunos tratamientos puede disminuir la producción de agua, asegurando menor consumo de energía (CO2) por cada barril de petróleo extraído

A communal catalogue reveals Earth’s multiscale microbial diversity

Our growing awareness of the microbial world’s importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth’s microbial diversity

A communal catalogue reveals Earth's multiscale microbial diversity

Our growing awareness of the microbial world's importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth's microbial diversity.Peer reviewe

Global, regional, and national incidence and mortality for HIV, tuberculosis, and malaria during 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013

BACKGROUND: The Millennium Declaration in 2000 brought special global attention to HIV, tuberculosis, and malaria through the formulation of Millennium Development Goal (MDG) 6. The Global Burden of Disease 2013 study provides a consistent and comprehensive approach to disease estimation for between 1990 and 2013, and an opportunity to assess whether accelerated progress has occured since the Millennium Declaration. METHODS: To estimate incidence and mortality for HIV, we used the UNAIDS Spectrum model appropriately modified based on a systematic review of available studies of mortality with and without antiretroviral therapy (ART). For concentrated epidemics, we calibrated Spectrum models to fit vital registration data corrected for misclassification of HIV deaths. In generalised epidemics, we minimised a loss function to select epidemic curves most consistent with prevalence data and demographic data for all-cause mortality. We analysed counterfactual scenarios for HIV to assess years of life saved through prevention of mother-to-child transmission (PMTCT) and ART. For tuberculosis, we analysed vital registration and verbal autopsy data to estimate mortality using cause of death ensemble modelling. We analysed data for corrected case-notifications, expert opinions on the case-detection rate, prevalence surveys, and estimated cause-specific mortality using Bayesian meta-regression to generate consistent trends in all parameters. We analysed malaria mortality and incidence using an updated cause of death database, a systematic analysis of verbal autopsy validation studies for malaria, and recent studies (2010-13) of incidence, drug resistance, and coverage of insecticide-treated bednets. FINDINGS: Globally in 2013, there were 1·8 million new HIV infections (95% uncertainty interval 1·7 million to 2·1 million), 29·2 million prevalent HIV cases (28·1 to 31·7), and 1·3 million HIV deaths (1·3 to 1·5). At the peak of the epidemic in 2005, HIV caused 1·7 million deaths (1·6 million to 1·9 million). Concentrated epidemics in Latin America and eastern Europe are substantially smaller than previously estimated. Through interventions including PMTCT and ART, 19·1 million life-years (16·6 million to 21·5 million) have been saved, 70·3% (65·4 to 76·1) in developing countries. From 2000 to 2011, the ratio of development assistance for health for HIV to years of life saved through intervention was US$4498 in developing countries. Including in HIV-positive individuals, all-form tuberculosis incidence was 7·5 million (7·4 million to 7·7 million), prevalence was 11·9 million (11·6 million to 12·2 million), and number of deaths was 1·4 million (1·3 million to 1·5 million) in 2013. In the same year and in only individuals who were HIV-negative, all-form tuberculosis incidence was 7·1 million (6·9 million to 7·3 million), prevalence was 11·2 million (10·8 million to 11·6 million), and number of deaths was 1·3 million (1·2 million to 1·4 million). Annualised rates of change (ARC) for incidence, prevalence, and death became negative after 2000. Tuberculosis in HIV-negative individuals disproportionately occurs in men and boys (versus women and girls); 64·0% of cases (63·6 to 64·3) and 64·7% of deaths (60·8 to 70·3). Globally, malaria cases and deaths grew rapidly from 1990 reaching a peak of 232 million cases (143 million to 387 million) in 2003 and 1·2 million deaths (1·1 million to 1·4 million) in 2004. Since 2004, child deaths from malaria in sub-Saharan Africa have decreased by 31·5% (15·7 to 44·1). Outside of Africa, malaria mortality has been steadily decreasing since 1990. INTERPRETATION: Our estimates of the number of people living with HIV are 18·7% smaller than UNAIDS's estimates in 2012. The number of people living with malaria is larger than estimated by WHO. The number of people living with HIV, tuberculosis, or malaria have all decreased since 2000. At the global level, upward trends for malaria and HIV deaths have been reversed and declines in tuberculosis deaths have accelerated. 101 countries (74 of which are developing) still have increasing HIV incidence. Substantial progress since the Millennium Declaration is an encouraging sign of the effect of global action. FUNDING: Bill & Melinda Gates Foundation

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio