Voltage compensation and power factor correction in distribution networks with DVR

The stability analysis and voltage regulation in distribution systems, as well as power quality problems such as voltage sags, swells, due to connection and disconnection of large loads, short circuits and the presence of non-linear loads, require of the consideration of adequate technical solutions. In this paper, a Dynamic Voltage Restorer ( DVR ) model based on a power converter scheme for voltage compensation due to the presence of sags of amplitude since 0.1pu to 0.9pu and swells with amplitude from 1.1pu to 1.9pu, and power factor correction in distribution networks is proposed. The results are verified through MATLAB & Simulink

Plan de mercadeo estratégico para la empresa Vehimotores 2006-2007

La empresa VEHIMOTORES en sus primeros cuatro años a experimentado un alto crecimiento en el mercado, pero a su vez esta enfrentando muchos retos tanto en su estructura interna como externa. La continua evolución del sector repuestero de la ciudad de Cali, los diferentes cambios tecnológicos que se esta sufriendo en la ciudad, y entre otros factores externos como políticos, legales, culturales y económicos que se ven a profundidad a lo largo de el informe hacen que VEHIMOTORES tenga una alta preocupación e incertidumbre por el futuro de la empresa. Esto hace que VEHIMOTORES se vea en la obligación de lograr mayor competitividad y buscar alternativas como la implementación y desarrollo de estrategias para la penetración de nuevos mercados en la ciudad de Cali y su periferia, empleando nuevos conocimientos de mercadeo estratégico que ayuden a la empresa a tener éxito en el mercado. A lo largo del informe se vera un análisis profundo y conciso de la empresa en su entorno interno y externo lo cual me llevaron a realizar un diagnostico donde plasmo la formulación del problema, el objetivo general, y los objetivos específicos, Esenciales para poder llegar a determinar la formulación de estrategias para la penetración del nuevo mercado. El nuevo mercado es el resultado de un arduo estudio y selección de alternativas plasmadas en el informe. A continuación el informe completo del plan de mercadeo estratégico realizado a la empresa VEHIMOTORESPasantía (Profesional en Mercadeo y Negocios Internacionales)-- Universidad Autónoma de Occidente. Facultad de Ingeniería, 2006PregradoProfesional en Mercadeo y Negocios Internacionale

Ellagic acid: Biological properties and biotechnological development for production processes

Ellagic acid, 2,3,7,8-tetrahydroxy-chromeno[5,4,3-cde]chromene-5,10-dione, is a powerful bioactive compound with many potential pharmacological and industrial applications. In this review, the chemical aspects, biological properties and diverse potential applications of ellagic acid for different industries were described. This review also discussed the advance in ellagitannin biodegradation, focusing on the process of isolation of microorganisms and strain selection, medium and culture optimization, as well as fermentation systems for commercially viable industrial scale production. The performances of various fermentation techniques that have been applied for the production of ellagic acid from residual by-products were compared, while the advantages and disadvantages of each plant source were also discussed.Key words: Ellagic acid, ellagitannin, biodegradation, fungal physiology, solid-state fermentation, submerged fermentation

Biochemical and molecular characterization of olive β-glucosidase in seven olive varieties during the ripening process: the role of β-glucosidase in determining the phenolic content of virgin olive oil.

Virgin olive oil (VOO) is one of the essential components of the Mediterranean diet, which includes a series of cultural habits, especially alimentary, shared to a greater or lesser extent, by all countries lapped by Mediterranean Sea. VOO is enriched with bioactive compounds which are related to its unique organoleptic characteristics, and also to its antioxidant properties, which have been associated to with the reduction of risk to suffer cardiovascular diseases and to a protective effect against cancer. The most important bioactive components in VOO are phenolics compounds [2].The phenolic composition of VOO is closely related to the content of phenolic glycosides initially present in the olive tissue. In parallel, some studies indicate that there is a positive correlation between the activity levels of β-glucosidase in the olive fruit and the final content of phenolic compounds in VOO. This enzyme plays a key role hydrolyzing phenolic profile of VOO. In consequence, its biochemical and molecular characterization is of great interest from a biotechnological point of view [1, 2].In this study, seven olive varieties (Abou-Kanani, Dokkar, Klon-14, Menya, Picual, Piñonera y Shengeh) with different phenolic contents have been selected in the World Olive Germplasm Bank. The phenolic profiles of fruits harvested at different ripening stages and their oils have been analyzed by HPLC and at the same time β-glucosidase activity has been measured in olive fruits at different ripening stages. The methods for β-glucosidase extraction and activity assessment have been optimized. Spectrophotometric activity assays have been carried out with the synthetic substrate p-nitrophenyl galactoside (p-NPG) using a calculated molar extinction coefficient (ε=552,8 M-1cm-1) for the p-nitrophenyl liberated in the reaction medium. The results obtained show that olive varieties with the highest content of phenolic glycosides in the fruit such as Piñonera, Dokkar or Menya, also have the largest β-glucosidase activity levels, which usually decrease ripening process. These results will be completed with the pertinent studies of gene expression [3]

Tolerance of native Magellan fungi in peat to anthracene and n-dodecane for potential use in bioremediation

Tolerance of Magellan fungi in peat to anthracene and n-dodecane for potential use in bioremediation. Cien. Inv. Agr. 43(1):85-93. The tolerances of filamentous Magellan fungi in peat were analyzed in the presence of structurally different petroleum hydrocarbons to assess their abilities for bioremediation in contaminated soils. Fungi on PDA (potato dextrose agar) and fresh peat plates were cultured and purified. The morphologically identified species were grown in a hydrocarbon adapted-fungi (HAF) medium. Increasing concentrations of anthracene, n-dodecane and furfural were applied to observe tolerances based on the radial growth kinetics of hyphae. The results showed that the radial growths of hyphae in anthracene reached average speeds of 10.95 ± 1.21, 11.03 ± 3.14 and 10.96 ± 4.61 mm h-1 in 0.1, 1 and 2 g L"¹ solutions, respectively. The average growth rates in n-dodecane were 10.52 ± 3.33, 14.67 ± 1.88 and 10.86 ± 3.50 mm h-1 in 10, 20 and 40 g L-1 solutions, respectively. The growth rate in furfural reached 3.95 ± 1.07 mm/h in a 5 g L-1 concentration. The results suggest that the identified filamentous fungi are tolerant to anthracene and n-dodecane, which are the primary components of petroleum fractions. Furfural, a recognized antifungal, limited the growth. The results also indicate hydrocarbon degradation, suggesting that Magellanic peat can be used as a potential inoculum in bioremediation treatment processes associated with petroleum-contaminated soils. The observed filamentous fungi belong to the Penicillium genus based on visual identification and 18S rRNA.Tolerancia a antraceno y n-dodecano de hongos nativos de turba Magallánica para su potencial uso en biorremediación. Cien. Inv. Agr. 43(1):85-93. Se estudia la tolerancia de hongos filamentosos de turba magallánica en presencia de hidrocarburos derivados del petróleo estructuralmente diferentes, con miras a ser empleados como agentes de biorremediación de suelos contaminados. Se cultivaron y purificaron hongos en placas con PDA (Agar de Papa y Dextrosa) y turba fresca. Las especies morfológicamente identificadas se cultivaron en medio HAF (Hidrocarbon Adapted-Fungi) con concentraciones crecientes de antraceno, n-dodecano y furfural para observar su tolerancia a través de las cinéticas de crecimiento radial de hifas. Los resultados muestran que el crecimiento radial de las hifas en antraceno alcanzó una velocidad media de 10.95 ± 1.21, 11.03 ± 3.14, y 10.96 ± 4.61 mm h4 para concentraciones de 0.1, 1 y 2 g L4; para n-dodecano las velocidades medias alcanzaron los 10.52 ± 3.33, 14.67 ± 1.88 y 10.86 ± 3.50 mm h4 para 10, 20 y 40 g L4. Ensayos con furfural alcanzaron 3.95 ± 1.07 mm h4 a 5 g L4. Los resultados muestran que el hongo filamentoso identificado es tolerante a antraceno y n-dodecano, constituyentes característicos de fracciones del petróleo. Por su parte furfural, reconocido antifúngico, limita el crecimiento. Los resultados también muestran degradación de los compuestos señalados posicionando a la turba Magallánica como potencial contribuyente de inóculos para procesos de biorremediación de suelos contaminados con hidrocarburos del petróleo. Se identificó el género Penicillium como el hongo filamentoso desarrollado mediante identificación visual y 18S RNA

FERTILIZACIÓN FOSFÓRICA Y POTÁSICA DE LA YUCA (MANIHOT SCULENTA, CRANTZ) EN ROTACIÓN DE CULTIVOS

Con el objetivo de determinar el posible efecto directo y residual del fósforo y el potasio en el rendimiento de la yuca colocada al final de la secuencia de cultivos y en el contenido de nutrientes en el suelo, se estudiaron diferentes sistemas de fertilización fosfórica y potásica en dos experimentos estacionarios sobre un suelo Ferralítico Rojo Compactado de la Estación Experimental "Juan Tomás Roig" de la Universidad de Ciego de Ávila, con bajo contenido de fósforo y alto contenido de potasio, típico de la provincia de Ciego de Ávila. La base de los tratamientos consistió en variar las cantidades de cada uno de los nutrientes utilizados desde dosis cero hasta altas aplicaciones a largo plazo para toda la rotación. Se encontraron altos rendimientos de la yuca cuando el suelo se encuentra medianamente abastecido en fósforo (P).  Por otra parte no se encontró respuesta en rendimiento, producción de masa seca, número de raíces por planta ni peso promedio de la raíz a las aplicaciones de potasio (K). Los contenidos de K intercambiable y P movible en el suelo mostraron diferencias significativas entre los tratamientos, con los mayores tenores en las dosis altas de fertilizante. Los resultados indican que es posible utilizar la yuca en un lugar postrero de la rotación sin que requiera de nuevas aplicaciones de P y K

Estudio de la investigación turística a través de las coautorías de artículos: cálculo de indicadores de colaboración y análisis de redes sociales

Se analiza la colaboración científica de las universidades catalanas en el campo del turismo entre 2000 y 2010. A partir de las coautorías de artículos, se calculan indicadores de colaboración simples y se examina la red colaboración. Se estudia la colaboración entre investigadores, instituciones y territorios. Los resultados muestran un aumento de la colaboración, diferencias entre las revistas y ausencia de relación entre colaboración y multidisciplinariedad. La red de colaboración presenta una baja densidad y varias subredes.Catalan universities scientific collaboration in tourism is analyzed, from 2000 to 2010. Through coauthorship data, simple collaboration indicators are calculated and the collaboration network is examined. Collaboration among researchers, institutions and territories is investigated. Results show an increase in collaboration, differences among journals, and absence of relationship between collaboration and multidisciplinarity. The collaboration network presents a low density and several subnetworks

Design and implementation in USRP of a preamble-based synchronizer for OFDM systems

The Orthogonal Frequency Division Multiplexing (OFDM) is one of the most widely adopted schemes in wireless technologies such as Wi-Fi and LTE due to its high transmission rates, and the robustness against Intersymbol Interference (ISI). However, OFDM is highly sensitive to synchronism errors, which affects the orthogonality of the carriers. We analyzed several synchronization algorithms based on the correlation of the preamble symbols through the implementation in Software-Defined Radio (SDR) using the Universal Software Radio Peripheral (USRP). Such an implementation was performed in three stages: frame detection, comparing the autocorrelation output and the average power of the received signal; time synchronism, where the cross-correlation based on the short and long preamble symbols was implemented; and the frequency synchronism, where the Carrier Frequency Offset (CFO) added by the channel was detected and corrected. The synchronizer performance was verified through the USRP implementation. The results serve as a practical guide to selecting the optimal synchronism scheme and show the versatility of the USRP to implement digital communication systems efficiently.Comment: 6 pages, to be presented at the ANDESCON - Biannual Technical and Scientific Conference of the Andean Council of the IEEE 202

Strict Anatomical Colocalization of Vitiligo and Elastolytic Granulomas

Vitiligo is the most common depigmenting disorder, with a worldwide occurrence of 0.1-2% in the general population. Multiple conditions have been described colocalized in vitiligo patches, like psoriasis or lichen planus. However, actinic granuloma has not been described in association with vitiligo lesions so far

Factores del retardo de consolidación en fracturas de antebrazo pediátricas

El objetivo de este estudio es determinar factores para el retardo de curación en fracturas pediátricas diafisarias de antebrazo. Presentamos un estudio caso-control de todas las fracturas pediáticas de antebrazo tratadas en el Hospital Universitario Miguel Servet, desde 2003 hasta 2009, y que presentaron retardo de consolidación, con un seguimiento mínimo de 12 meses. Los criterios de exclusión fueron fractura-luxación, infección, osteosíntesis insuficiente, fractura en tallo verde, abierta, patológica y asociada a fractura de cabeza radial, así como pacientes sin el seguimiento mínimo establecido. El cálculo estadístico incluyó análisis de regresión lineal bivariante y multivariante. Resultados: Durante este periodo se trataron 441 fracturas de antebrazo completas, de ambos huesos: 14 de ellas (3.2%) sufrieron retardo de consolidación; y 63 controles cumplieron los criterios de inclusión y fueron seleccionados aleatoriamente. El análisis bivariante mostró diferencias significativas entre los grupos "retardo de consolidación" y "control" en edad, necesidad de tratamiento quirúrgico, reducción abierta frente a cerrada y tiempo hasta retirada del material. Si embargo, la reducción abierta de la fractura, más frecuente en el grupo "retardo de consolidación", fue la única variable que permaneció asociada en el análisis multivariante. Conclusiones: El factor predictivo más importante para el retardo de consolidación en fracturas pediátricas de antebrazo es la reducción abierta.The aim of this study was to assess predictive factors for delayed healing in forearm paediatric fractures. This is a case-control study of all paediatric shaft fractures of forearm presenting delayed union in follow-up period of 12 months or more, from 2003 through 2009, treated in Miguel Servet University Hospital. Exclusion criteria were fracture-dislocations, infection, suboptimal osteosynthesis, greenstick, open, pathologic and associated radial head fractures, as well as patients without stablished period of follow up. Statistical assessment included bivariant and multivariant linear regression analysis. Results: During the study period 441 complete both-bone forearm fractures were treated: 14 of them (3.2%) were identified as suffering delayed union; and 63 controls fulfilling inclusion criteria were randomly selected. Bivariant analysis showed significant differences between "delayed union" and "control" groups in age, need of surgical treatment, open versus closed reduction and mean time to hardware removal. However, open reduction of the fracture, more frequent in the "delayed union" group, was the only variable which remained associated in the multivariant analysis. Conclusions: The strongest predictor of union delay in paediatric forearm fractures is open reduction