712 research outputs found
Separating expansion from contraction: generalized TOV condition, LTB models with pressure and CDM
We discuss the existence of a dividing shell separating expanding and
collapsing regions in spherically symmetric solutions with pressure. We obtain
gauge invariant conditions relating not only the intrinsic spatial curvature of
the shells to the ADM mass, but also a function of the pressure which we
introduce that generalises the Tolman-Oppenheimer-Volkoff equilibrium
condition, in the framework of a 3+1 spacetime splitting. We consider the
particular case of a Lema\^itre-Tolman-Bondi dust models with a cosmological
constant (a -CDM model) as an example of our results.Comment: Proceedings of 'Invisible Universe International Conference', Paris,
June 29- July 3, 2009 ; 5pp, 4 fig
Mass transfer and hydrodynamics in multiphase systems
Tese de doutoramento. Engenharia Química. Faculdade de Engenharia. Universidade do Porto. 200
LTTP Data Analysis: Factors Affecting Pavement Roughness for the State of California
The contributions of pavement structure and features, rehabilitation techniques, climatic conditions, traffic levels, layer materials and properties, pavement distress, and other factors causing changes in pavement smoothness are not well documented. As a result, it becomes difficult to select the appropriate pavement structure, design features and rehabilitation strategies to ensure pavement smoothness. This study focuses on analysing the available LTPP data for asphalt pavements in California by investigating the correlation between the pavement roughness and the effect of pavement temperature, precipitation, fatigue, age of pavement, rutting, and the average annual daily truck traffic. IRI has been identified as the factor characterizing pavement smoothness. Results indicated that when diving pavement sections between three different groups according to the annual precipitation for pavement section in the State of California, the IRIchange can be predicted with 93.5% accuracy for sections with less than 200mm of annual precipitation, 85.9% accuracy for sections with annual precipitation between 200mm and 90mm, and 90.1% for sections with annual precipitation higher than 900mm
Rapid and comprehensive evaluation of (poly)phenolic compounds in pomegranate (punica granatum L.) juice by UHPLC-MSn
The comprehensive identification of phenolic compounds in food and beverages is a crucial starting point for assessing their biological, nutritional, and technological properties. Pomegranate (Punica granatum L.) has been described as a rich source of (poly)phenolic components, with a broad array of different structures (phenolic acids, flavonoids, and hydrolyzable tannins) and a quick, high throughput, and accurate screening of its complete profile is still lacking. In the present work, a method for UHPLC separation and linear ion trap mass spectrometric (MSn) characterization of pomegranate juice phenolic fraction was optimized by comparing several different analytical conditions. The best solutions for phenolic acids, anthocyanins, flavonoids, and ellagitannins have been delineated and more than 70 compounds have been identified and fully characterized in less than one hour total analysis time. Twenty-one compounds were tentatively detected for the first time in pomegranate juice. The proposed fingerprinting approach could be easily translated to other plant derived food extracts and beverages containing a wide array of phytochemical compounds
LTPP Data Analysis: Factors Affecting Pavement Roughness for the State of California
The contributions of pavement structure and features, rehabilitation techniques, climatic conditions, traffic levels, layer materials and properties, pavement distress, and other factors causing changes in pavement smoothness are not well documented. As a result, it becomes difficult to select the appropriate pavement structure, design features and rehabilitation strategies to ensure pavement smoothness. This study focuses on analysing the available LTPP data for asphalt pavements in California by investigating the correlation between the pavement roughness and the effect of pavement temperature, precipitation, fatigue, age of pavement, rutting, and the average annual daily truck traffic. IRI has been identified as the factor characterizing pavement smoothness. Results indicated that when diving pavement sections between three different groups according to the annual precipitation for pavement section in the State of California, the IRIchange can be predicted with 93.5% accuracy for sections with less than 200mm of annual precipitation, 85.9% accuracy for sections with annual precipitation between 200mm and 90mm, and 90.1% for sections with annual precipitation higher than 900mm
LTTP Data Analysis: Factors Affecting Pavement Roughness for the State of California
The contributions of pavement structure and features, rehabilitation techniques, climatic conditions, traffic levels, layer materials and properties, pavement distress, and other factors causing changes in pavement smoothness are not well documented. As a result, it becomes difficult to select the appropriate pavement structure, design features and rehabilitation strategies to ensure pavement smoothness. This study focuses on analysing the available LTPP data for asphalt pavements in California by investigating the correlation between the pavement roughness and the effect of pavement temperature, precipitation, fatigue, age of pavement, rutting, and the average annual daily truck traffic. IRI has been identified as the factor characterizing pavement smoothness. Results indicated that when diving pavement sections between three different groups according to the annual precipitation for pavement section in the State of California, the IRIchange can be predicted with 93.5% accuracy for sections with less than 200mm of annual precipitation, 85.9% accuracy for sections with annual precipitation between 200mm and 90mm, and 90.1% for sections with annual precipitation higher than 900mm
Variations in caffeine and chlorogenic acid contents of coffees: what are we drinking?
The effect of roasting of coffee beans and the extraction of ground coffee with different volumes of hot pressurised water on the caffeine and the total caffeoylquinic acids (CQAs) content of the resultant beverages was investigated. While caffeine was stable higher roasting temperatures resulted in a loss of CQAs so that the caffeine/CQA ratio was a good marker of the degree of roasting. The caffeine and CQA content and volume was determined for 104 espresso coffees obtained from coffee shops in Scotland, Italy and Spain, limited numbers of cappuccino coffees from commercial outlets and several instant coffees. The caffeine content ranged from 48–317 mg per serving and CQAs from 6–188 mg. It is evident that the ingestion of 200 mg of caffeine per day can be readily and unwittingly exceeded by regular coffee drinkers. This is the upper limit of caffeine intake from all sources recommended by US and UK health agencies for pregnant women. In view of the variable volume of serving sizes, it is also clear that the term “one cup of coffee” is not a reproducible measurement for consumption, yet it is the prevailing unit used in epidemiology to assess coffee consumption and to link the potential effects of the beverage and its components on the outcome of diseases. More accurate measurement of the intake of coffee and its potentially bioactive components are required if epidemiological studies are to produce more reliable information
Forma urbana y acción pública: las Setas de Sevilla como escenario de las protestas del 15-M
An analysis of the creation and transformation of the Plaza de la Encarnación in Seville, the last of the city’s projects for a “plaza mayor”, serves here as a starting point for a contemporary approach to the phenomena of public space architecture. The Encarnación was structured from its very beginning, during the French rule of 1810–1812, as a "twofold" perimeter: a convex square enclosing a concave building, the Central Market. In this sense, it has rejected time and again the imposition of a general order or concept which it lacks, accepting only interventions that rely on its centrality value. The public competition for its total remodeling, won in 2004 and executed by German-based architecture studio J. Mayer H., put an end to decades of neglect in order to return to a morphology that, although in some aspects perpetuates the same nineteenth-century spatiality, has also provided—whether consciously or not—a potential for political assemblage. This contribution became evident during the 15-M demonstrations, continually held in the Plaza, showing the capacity of architecture to decisively transform the occupation of public space.El análisis de la gestación y transformación de la plaza de la Encarnación de Sevilla, última de las «plazas mayores» de la ciudad, permite un acercamiento contemporáneo a los fenómenos de la arquitectura del espacio público. La Encarnación se constituyó desde su inicio, durante la dominación francesa de 1810–1812, como un perímetro «duplicado»: una plaza convexa rodeando un edificio, el Mercado Central. En ese sentido, se ha mostrado continuamente refractaria a la imposición de un orden o concepto general de los cuales carece, acogiendo únicamente actuaciones que se apoyan en su valor de centralidad. El concurso público para su remodelación total, ganado en 2004 y ejecutado por el estudio alemán J. Mayer H., puso fin a décadas de abandono para regresar a una morfología que, si bien en algunos aspectos perpetúa la espacialidad decimonónica, también ha aportado, consciente o inconscientemente, un potencial para el asamblearismo político patente durante su utilización por las manifestaciones del 15-M y que reivindica la capacidad de la arquitectura para transformar la ocupación del espacio público
Pla director de la xarxa de clavegueram del municipi de Copons
El Pla Director de Clavegueram de Copons té dos objectius. El primer, és conèixer la situació actual de la xarxa de clavegueram, pel que fa a la seva geometria (cartografia), així com conèixer el seu funcionament hidràulic.
El segon, com a continuació del primer, consisteix en fer una proposta d'actuacions per tal de garantir el correcte funcionament de la xarxa, avui dia, i una vegada s‟hagi consolidat totalment el desenvolupament urbanístic previst a l‟àmbit d‟aquest Pla Director.
La redacció d'aquest Pla Director sorgeix de la voluntat de l‟ajuntament de Copons per conèixer, i abordar la millor solució als problemes actuals que presenta el clavegueram del municipi, i d'aquesta forma, contribuir a la millora del servei i del medi ambient del terme municipal.
Cal destacar, entre d'altres, dues aportacions essencials d'aquest Pla. D'una banda pel que fa a la metodologia, de la utilització per l'estudi del funcionament hidràulic, d‟un model de simulació matemàtica (programa informàtic que permet reproduir el comportament del clavegueram de forma exacta a l'ordinador) dels anomenats de nivell III (màxima precisió). Això serveix de base per a comprovar els importants beneficis que genera un treball d'aquestes característiques, ja que ajuda a un major coneixement de la xarxa i de la seva problemàtica, i per tant permet reduir enormement les inversions necessàries per arranjar-la.
D'altra banda, es realitza una inspecció de la xarxa de clavegueram (a partir de la inspecció visual des dels pous de registre) per determinar la seva topologia, les seves característiques principals i el seu estat, així com per detectar possibles problemes que puguin afectar-la. Com a resultat d‟aquesta tasca es presenta el inventari de la xarxa de clavegueram que és l‟element bàsic a partir del qual es realitza l‟estudi i les propostes d‟actuació.
De cara al gestor de la xarxa de clavegueram de Copons, els objectius a assolir perla redacció d‟aquest Pla Director seran:
Conèixer la xarxa de clavegueram des del seu punt de vista estructural (geometria i estat) i des del seu comportament hidràulic davant cabals d‟aigües residuals i episodis de pluja de diferents intensitats. El Pla Director permet com a gran avantatge disposar d‟una visió global de la xarxa de clavegueram.
Definir les ampliacions i millores de la xarxa, requerides per exigències ja plantejades o per les necessitats previsibles en el futur dins d'un marc general que permeti la realització dels projectes de cadascuna de les actuacions definides, de forma que vagin configurant, planificadament, un sistema general de drenatge modern, equilibrat, eficaç i suficient per atendre les necessitats previstes a curt, mig i llarg termini. Aquestes actuacions no es redueixen a necessitats estructural i hidràuliques sinó també mediambientals.
Optimitzar l'aprofitament de la infraestructura de clavegueram existent en l'actualitat.
Valorar econòmicament cadascuna de les actuacions definides.
De cara al ciutadà provocarà tota una sèrie de beneficis com:
Reduir les actuacions d‟emergències relacionades amb la insuficiència de la xarxa, i potenciar les actuacions programades, en que es pot escollir el millor moment de l‟any per actuar.
Reduir les molèsties produïdes per les descàrregues del sistema unitari fora del medi en episodis de pluja de moderada intensitat.
Al tenir una visió global del sistema es pot actuar de manera ordenada i optimitzada, reduint el nombre d‟actuacions, i per tant les afeccions a la via pública.
Es per tots aquests motius, entre altres, que es redacta el present Pla Director de Copon
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