Numerical simulation and experiments of the multiphase flow in a liquid-liquid cylindrical cyclone separator

A Liquid-Liquid Cylindrical Cyclone separator (LLCC) is a device used in the petroleum industry to separate the oil-water mixture obtained from the well. The use of this device has not been widespread due to the lack of tools for predicting its separation capability. This paper presents a numerical and experimental study of the fluid dynamic performance of this type of cylindrical cyclone separators. The use of numerical simulations would reduce the time and cost necessary to obtain information for predicting the behavior of the equipment. The objective of this study is to determine if CFD (Computational Fluid Dynamics) techniques are able to reproduce the behavior of a LLCC separator. The CFD software examined was ANSYS-CFX 5.6TM and numerical simulations were carried out using the dispersed model with oil as the dispersed phase. The oil and water mixture entering the separator is divided due to centrifugal and buoyancy forces in an upper (oil rich) exit and a bottom (water rich) exit. The separation capability is determined as the maximum amount of water removed from the mixture with the minimum amount of oil content in the water rich exit. The experiments were conducted in a transparent LLCC separator that allows the visualization of the mixture and the measurement of the oil content. Experiments were conducted for three variables: mixture velocity and water content at the entrance, and the split ratio. The split ratio is defined as the bottom exit flow rate divided by the water flow rate at the entrance. The results showed that CFD tools are able to reproduce the oil content obtained from the experiments for all analyzed conditions. Additionally, the mixture distribution images from numerical and experimental data showed good agreement. This study confirms the capacity of CFD tools for the multiphase flow analysis of LLCC separators

Numerical simulation and experiments of the multiphase flow in a liquid-liquid cylindrical cyclone separator

A Liquid-Liquid Cylindrical Cyclone separator (LLCC) is a device used in the petroleum industry to separate the oil-water mixture obtained from the well. The use of this device has not been widespread due to the lack of tools for predicting its separation capability. This paper presents a numerical and experimental study of the fluid dynamic performance of this type of cylindrical cyclone separators. The use of numerical simulations would reduce the time and cost necessary to obtain information for predicting the behavior of the equipment. The objective of this study is to determine if CFD (Computational Fluid Dynamics) techniques are able to reproduce the behavior of a LLCC separator. The CFD software examined was ANSYS-CFX 5.6TM and numerical simulations were carried out using the dispersed model with oil as the dispersed phase. The oil and water mixture entering the separator is divided due to centrifugal and buoyancy forces in an upper (oil rich) exit and a bottom (water rich) exit. The separation capability is determined as the maximum amount of water removed from the mixture with the minimum amount of oil content in the water rich exit. The experiments were conducted in a transparent LLCC separator that allows the visualization of the mixture and the measurement of the oil content. Experiments were conducted for three variables: mixture velocity and water content at the entrance, and the split ratio. The split ratio is defined as the bottom exit flow rate divided by the water flow rate at the entrance. The results showed that CFD tools are able to reproduce the oil content obtained from the experiments for all analyzed conditions. Additionally, the mixture distribution images from numerical and experimental data showed good agreement. This study confirms the capacity of CFD tools for the multiphase flow analysis of LLCC separators

Notas sobre la nidificación del nictibio grande (Nyctibius Grandis) en la Guayana Venezolana | Notes about nesting of great potoo (nctibius grandis) in Venezuelan Guaiana

La biología reproductiva del Nictibio Grande (Nyctibius grandis) es escasamente conocida; de hecho, en Venezuela hay un solo registro de nidificación en la especie. En la región de Guayana, en marzo de 2003, durante la fase de inundación de la represa Caruachi, en el tramo inferior del río Caroní (estado Bolívar, Venezuela), se fotografió un ejemplar de N. grandis incubando un huevo (diámetro interpolar: 52 mm; diámetro ecuatorial: 37 mm; peso: 37 g) sobre una rama desnuda. La coloración del huevo era blanca con manchas pequeñas negruzcas y gris azulado claro hacia el polo romo. Esta sería la primera documentación fotográfica e información de las dimensiones del huevo en esta especie. Palabras clave: Nyctibius grandis, anidación, Venezuela. ABSTRACT Little is known of the breeding biology of Potoo (Nyctibius grandis); in fact, there is only one study about nesting of this species in Venezuela. In the Guayana region, on march 2003, during the flooding phase of the newly built Caruachi Dam, in the lower Caroní river (Bolivar state, Venezuela), one adult N. grandis was photographed incubating a single egg (interpolar diameter: 52 mm; equatorial diameter: 37 mm; weight: 37 g) on a naked tree branch. The egg was white with blackish and dull blue gray dots in its round pole. This is the first photographic record and measurements information of the egg in this species. Key words: Nyctibius grandis, nesting, Venezuela

DIETA DE TRES ESPECIES DE AVES COLÚMBIDAS EN UN HÁBITAT XEROFÍTICO LITORAL DEL NORORIENTE DE VENEZUELA

Las aves colúmbidas tienen distribución mundial, pero han sido poco estudiadas en su ecología alimentaria. Con la finalidad de analizar la variación temporal de los componentes de la dieta en tres especies típicas del bosque acantoxeromorfo litoral del Nororiente de Venezuela, i.e., Columbina squammata, Columbina passerina y Leptotila verreauxi, se practicaron capturas mensuales a lo largo de un año, utilizando redes de niebla, y se les administró el emético tartrato de antimonio-potasio 1,5%, para obtener el regurgitado. Los renglones fueron identificados hasta la categoría género y/o especie. Las tres especies consumieron mayoritariamente semillas (n=21 spp) , eventualmente, invertebrados (insectos y moluscos) y piedrecillas. La mayor diversidad de renglones se presentó durante la época de lluvias. C. squammata mostró el más amplio espectro alimentario, por lo que se presume como la de mayor éxito adaptativo a estos ambientes semiáridos; C. passerina el mayor índice de repleción; mientras, L. verreauxi consumió las semillas de mayor tamaño. Se evidencia un traslape parcial de los nichos alimentarios de C. passerina y C. squammata (coincidieron en el 57% de los renglones). Euphorbia maculata fue la única especie común en las tres palomas. Los renglones consumidos con mayor frecuencia recayeron en Euphorbiacea, Malvaceae y Poaceae. La preferencia por determinadas especies vegetales estaría condicionada a factores fenológicos (e.g., frutificación), fisioanatómicos (e.g., tamaño, digestibilidad) y coevolutivos (e.g., endozoocoria). La conducta alimentaria generalista mostrada de las tres especies parece indicar fluctuaciones temporales en la disponibilidad de los recursos alimentarios.   Palabras clave: Dieta, Columbina squammata, Columbina passerina, Leptotila verreauxi. ABSTRACT Columbidae birds have a worldwide distribution but their alimentary ecology has been somewhat neglected. We endeavored to analyze seasonal variations in the diet of three typical species of the littoral xeric forests in the northeast of Venezuela: Columbina squammata, Columbina passerine, and Leptotila verreauxi. Monthly captures using mist nets were carried out all year long. After being netted, the birds were fed an emetic, 1.5% antimony potassium tartrate, to get them to regurgitate. Items were identified up to the genus and/or species category. The three species primarily consumed seeds (n = 21 spp), progressing eventually to invertebrates (insects and mollusks) and tiny stones. The greatest item diversity was during the rainy season. C. squammata showed the widest feeding scope, suggesting a greater capacity for adaptation and survival in these semiarid habitats. C. passerine revealed the greatest repletion rate, and L. verreauxi ingested the largest seeds. A partial overlap of feeding niches for C. passerine and C. squammata was observed (with an item coincidence of 57%). Euphorbia maculate was the only common species of the three doves. Euphorbiacea, Malvaceae,and Poaceae were the food staples most frequently consumed, a preference for determinate vegetal species possibly being conditioned to phenological (e.g., fruiting patterns), physioanatomical (e.g., size, digestability), and coevolutive (e.g., endozoochory mechanisms) factors. The generalist feeding behavior exhibited by the three species seems to indicate seasonal fluctuations in the availability of food resources.   Key words: Diet, Columbina squammata, Columbina passerina, Leptotila verreaux

The effect of potential supramolecular-bond promoters on the DNA-interacting abilities of copper-terpyridine compounds.

Three copper(II) coordination compounds have been prepared from three different 2,2′:6′,2′′-terpyridine-based ligands, which have been selected to investigate the potential role of supramolecular interactions on the DNA-interacting and cytotoxicity properties of the corresponding metal complexes. Hence, the ligands 4′-((naphthalen-2-yl)methoxy)-2,2′:6′,2′′-terpyridine (Naphtpy) and 4′-((1H-benzo[d]imidazol-2-yl)methoxy)-2,2′:6′,2′′-terpyridine (Bimztpy) have been synthesized from commercially-available 4′-chloro-2,2′:6′,2′′-terpyridine (Cltpy), and their copper(II) complexes have been obtained by reaction with copper(II) nitrate. The DNA-interacting abilities of the corresponding compounds [Cu(Cltpy)(H2O)(NO3)2] (1), [Cu(naphtpy)(NO3)(H2O)](NO3)(MeOH) (2) and [Cu(bimztpy)(NO3)(H2O)](NO3) (3) have been investigated using different techniques, and cytotoxicity assays with several cancer cell lines have revealed interesting features, viz. the more efficient complex is 2, which although it does not act as a DNA cleaver, displays the most effective DNA-interacting and cytotoxic properties, compared to 1 and 3

El diplomado su dinámica y diseño curricular. The diploma course: its dynamic and curricular design

Se realiza una investigación partiendo de la insuficiencia que presentan en la formación pedagógica los docentes de la Facultad de Ciencias Médicas "Dr. Ernesto Che Guevara de la Serna", con el propósito de contribuir al perfeccionamiento de la Educación Médica Superior, específicamente en el postgrado, al determinar la fundamentación teórica-pedagógica y didáctica para el proceso docente - educativo postgraduado de los profesionales de la Salud que ejercen función docente, que tome en cuenta su estructura y dinámica, el sistema de leyes que lo rigen y las regularidades que se manifiesten en este proceso en particular, a través del diseño de un programa de Diplomado en Ciencias de la Educación Médica Superior que tiende a eliminar todo carácter empírico. Se tomarán en consideración los métodos científicos de investigación: histórico, lógico, dialéctico, análisis documental, empíricos y sistémico-estructural entre otros. Se arriban a conclusiones y recomendaciones. DeCS: EDUCACIÓN MÉDICA, ESCUELAS MÉDICAS, DOCENCIA MÉDICA, PEDAGOGÍA. ABSTRACT A research paper was carried out considering the inadequacies present in the pedagogical training of the teaching staff at “Dr. Ernesto Guevara de la Serna” Medical School to contribute to the improvements of Higher Medical Education, specifically post-graduate education, determining the theoretical, pedagogical and didactic bases to the teaching-educational postgraduate process of the health professionals with the practice of teaching activities, taking into account its structure and dynamics, the system of laws to its function and the regularities that determine this process in particular, carrying it by means of a syllabus design for a Diploma course in Higher Medical Education; which course might tend to eliminate all of the empiric character. Scientific methods of research such as: historical, logical, dialectic, documentary analysis, empiric and systemic-structural were taken into consideration. Conclusions and recommendations were given. DeCS: Medical education; medical schools; medical teaching; pedagogy

El diplomado su dinámica y diseño curricular. The diploma course: its dynamic and curricular design

Se realiza una investigación partiendo de la insuficiencia que presentan en la formación pedagógica los docentes de la Facultad de Ciencias Médicas "Dr. Ernesto Che Guevara de la Serna", con el propósito de contribuir al perfeccionamiento de la Educación Médica Superior, específicamente en el postgrado, al determinar la fundamentación teórica-pedagógica y didáctica para el proceso docente - educativo postgraduado de los profesionales de la Salud que ejercen función docente, que tome en cuenta su estructura y dinámica, el sistema de leyes que lo rigen y las regularidades que se manifiesten en este proceso en particular, a través del diseño de un programa de Diplomado en Ciencias de la Educación Médica Superior que tiende a eliminar todo carácter empírico. Se tomarán en consideración los métodos científicos de investigación: histórico, lógico, dialéctico, análisis documental, empíricos y sistémico-estructural entre otros. Se arriban a conclusiones y recomendaciones. DeCS: EDUCACIÓN MÉDICA, ESCUELAS MÉDICAS, DOCENCIA MÉDICA, PEDAGOGÍA. ABSTRACT A research paper was carried out considering the inadequacies present in the pedagogical training of the teaching staff at “Dr. Ernesto Guevara de la Serna” Medical School to contribute to the improvements of Higher Medical Education, specifically post-graduate education, determining the theoretical, pedagogical and didactic bases to the teaching-educational postgraduate process of the health professionals with the practice of teaching activities, taking into account its structure and dynamics, the system of laws to its function and the regularities that determine this process in particular, carrying it by means of a syllabus design for a Diploma course in Higher Medical Education; which course might tend to eliminate all of the empiric character. Scientific methods of research such as: historical, logical, dialectic, documentary analysis, empiric and systemic-structural were taken into consideration. Conclusions and recommendations were given. DeCS: Medical education; medical schools; medical teaching; pedagogy

Soluble concentrations of the terminal complement complex C5b-9 correlate with end-organ injury in preeclampsia

Q3Q1Pacientes embarazadas hipertensasObjective: We sought to determine if soluble levels of C5b-9, the terminal complement complex, correlate with end-organ injury in preeclampsia. Study Design: Project COPA (Complement and Preeclampsia in the Americas), a multi-center observational study in Colombia from 2015 to 2016, enrolled hypertensive pregnant women into four groups: chronic hypertension, gestational hypertension, preeclampsia, and preeclampsia with severe features. Trained coordinators collected clinical data, blood and urine. End-organ injury was defined by serum creatinine ≥ 1.0 mg/dl, aspartate transaminase ≥ 70U/L, platelet count < 150,000/µl, or lactate dehydrogenase ≥ 500 U/L. Data were analyzed by χ2 or Fisher’s exact test with significance at P < 0.05. Main Outcome Measure: C5b-9 concentrations in plasma and urine, using enzyme linked immunosorbent assays. Results: In total, 298 hypertensive participants were enrolled. Plasma and urine C5b-9 levels were measured in all participants and stratified by quartile (Q1-4), from lowest to highest C5b-9 concentration. Participants with low plasma C5b-9 levels (Q1) were more likely to have end-organ injury compared to those with higher levels (Q2-Q4) [platelet count < 150,000/μl (20.8% vs. 8.4%, P = 0.01); elevated serum creatinine ≥ 1.0 mg/dl (14.9% vs. 4.5%, P = 0.009)]. In contrast, participants with high urinary C5b-9 levels (Q4) were more likely to have end-organ injury compared to those with lower levels (Q1-Q3) [platelet count < 150,000/μl (19.7% vs. 7.4%, P = 0.003); elevated serum creatinine ≥ 1.0 mg/dl (12.3% vs. 4.4%, P = 0.025)]. Conclusion: We identified a pattern of increased urine and low plasma C5b-9 levels in patients with preeclampsia and end-organ injury. Soluble C5b-9 levels may be used to identify complement-mediated end-organ injury in preeclampsia.https://orcid.org/0000-0001-6822-0374Revista Internacional - IndexadaA1N