An assessment of a simplified methodology for determining the thermal performance of thermo-active piles

Ground source energy systems provide low-carbon heating and cooling to buildings, but their efficient deployment requires a reliable estimate of their thermal performance. A simplified methodology is presented to determine the thermal performance of thermo-active piles when heating or cooling loads are specified with either inlet pipe temperatures or imposed heat fluxes. The proposed methodology avoids computationally expensive 3D analyses and the explicit simulation of heat exchanger pipes, relying instead on 2D thermal analyses. When the heating or cooling of a thermo-active pile is assessed by imposing inlet pipe temperatures, the proposed methodology allows the determination of the power of pile per unit length. Conversely, when heating or cooling loads are specified via extracted or injected heat fluxes, the inlet and outlet fluid temperatures, as well as average temperatures at pile wall, are determined. The proposed methodology has been shown to reproduce accurately the thermal performance of thermo-active piles modelled using 3D analyses where heat exchanger pipes are explicitly simulated, considering different patterns of heating and cooling cycles. The application of the proposed methodology to the case of a real thermo-active pile is demonstrated by comparing its predicted thermal performance with the results of a well-documented field thermal response test

La brotación y la floración del kiwi en función de las temperaturas invierno - primaverales de la región central de Córdoba

p.183-188Se analizaron la brotación y floración del kiwi en relación a la acumulación de unidades Richardson en dos localidades de la región central de Córdoba durante las campañas agrícolas 1990-91 y 1991-92. Se observaron diferencias significativas entre los cultivares Hayward y M- 54 en cuanto a las fechas de ocurrencia de la brotación. El porcentaje de yemas brotadas estuvo relacionado con el nivel del enfriamiento invernal. Asimismo, la duración de la floración, en particular de las flores femeninas, se reduce al producirse una mayor acumulación de unidades de Richardson. Las condiciones meteorológicas registradas en las localidades estudiadas durante el período de la dormición invernal fueron propicias para el posterior desarrollo de la brotación y floración del kiwi

Development of a practical heat of hydration model for concrete curing for geotechnical applications

Thermal integrity profiling (TIP) is a common non-destructive technique to evaluate the quality of construction of piles by analysing the temperature fields due to heat of hydration from freshly cast concrete piles. For this process to be accurate, a reliable concrete heat of hydration model is required. This paper proposes a practical and simple to calibrate four parameter model for the prediction of concrete heat of hydration. This model has been shown to be able to reproduce the evolution of heat of hydration measured in laboratory tests, as well as field measurements of temperature within curing concrete piles, as part of a thermal integrity profiling (TIP) operation performed at a site in London. With the simplicity of the model and the small number of model parameters involved, this model can be easily and quickly calibrated, enabling quick predictions of expected temperatures for subsequent casts using the same concrete mix

Severe intracranial haemorrhage in neonatal alloimmune thrombocytopenia

Neonatal alloimmune thrombocytopenia is a rare (1/1000-5000 births) life-threatening disorder, caused by fetomaternal incompatibility for a fetal human platelet alloantigen inherited from the father, with production of maternal alloantibodies against fetal platelets, leading to severe thrombocytopenia and potential bleeding. Intracranial haemorrhage is the most feared complication. This report presents the case of a term newborn infant, born from caesarean section after a normal pregnancy, presenting signs of skin bleeding with different ages. Obstetric history included a previous spontaneous abortion after amniocentesis. Severe thrombocytopenia (4×10(9)/l platelets) was found and brain ultrasound showed multiple intracranial haemorrhages. Human platelet antigen (HPA) phenotyping showed maternal negative HPA-1a and paternal positive HPA-1a platelets. Strongly positive anti-HPA-1a and weakly positive anti-human leukocyte antigen class I alloantibodies were found in the mother. Multiple platelet transfusions, intravenous immunoglobulin and corticosteroid were given but favourable response was accomplished only after a compatible platelet transfusion. Brain MRI showed multiple subacute and chronic haemorrhages

Measurements of suspended sediment transport on a reflective mesotidal beach in southern Portugal

The present paper reports the results obtained in a field experiment carried out on a medium- energy, mesotidal, reflective beach on Culatra Island (southern Portugal). Simultaneous time-series measurements of waves, currents and sediment concentration were taken during 1.5 tidal cycles using a pressure transducer, two bidirectional electromagnetic current-meters and three optical backscatter sensors. Measurements of suspended sediment transport were compared with fluorescent sand tracers. Total longshore sediment fluxes measured with optical techniques and sand tracers were found to give similar results, if their major limitations are considered. The present experiment confirms the different sedimentary behaviours of steep reflective beaches with plunging breakers, as opposed to the low-gradient beaches with spilling breakers where most previous studies have been performed, and supports the idea that one of the major limitations of longshore sediment transport models is their lack of dependency on breaker/beach type.Se presentan los resultados de un experimento realizado en una playa reflectiva, mesotidal y de media energía, en la isla de Culatra (sur de Portugal). Se llevaron a cabo mediciones de series temporales de olas, de corrientes y de concentración de sedimento en suspensión durante un ciclo tidal y medio, utilizando un transductor de presión, dos correntímetros bidireccionales electromagnéticos y tres sensores ópticos. Se constató que los resultados de medir los flujos sedimentarios con las técnicas ópticas y con arenas marcadas eran semejantes, teniendo en cuenta las respectivas limitaciones. El presente experimento ha confirmado el desigual comportamiento sedimentario de playas reflectivas con fuerte inclinación y rompiente en voluta, en oposición a las playas con pequeña inclinación y rompiente en derrame, apoyando, pues, la idea de que una de las mayores limitaciones de los modelos de deriva litoral es la ausencia de dependencia en relación al tipo de playa/ rompiente.Instituto Español de Oceanografí

A practical method for calculating thermally-induced stresses in pile foundations used as heat exchangers

Thermo-active piles are capable of providing both structural stability as foundations and low carbon heating and cooling as ground source heat exchangers. When subjected to heating or cooling, the soil surrounding the pile restricts its expansion or contraction, giving rise to thermally-induced axial stresses, which need to be considered during design. Previous numerical studies often assume axisymmetry of the problem and/or a simplification of the heating or cooling mechanism of the pile. To simulate accurately the development of thermallyinduced axial stresses, this paper presents a computational study comprising three dimensional fully coupled thermo-hydro-mechanical finite element analyses conducted using the Imperial College Finite Element Program (ICFEP), where the heating of a thermo-active pile is simulated by prescribing a flow of hot water through the heat exchanger pipes within the pile. The effects of pipe arrangement on thermally-induced axial stresses are investigated by considering three different cases – single U loop, double U-loop and triple U-loop. Since threedimensional analyses are computationally expensive, a simplified method using a combination of two-dimensional analyses is proposed to estimate the thermally-induced axial stresses, which is subsequently validated and shown to yield accurate results

CONTROLE DA PRESSÃO INTRCUFF EM DOENTES TRAQUEOSTOMIZADOS

CONTROLE DA PRESSÃO INTRCUFF EM DOENTES TRAQUEOSTOMIZADOS Álvara Silva1, Ana Taborda1, Hélder Vilarinho1, Inês Rocha1, Olinda Vieira1, Rosa Silva1. 1Serviço de de Traumatologia Craneo Encefálica (TCE), HSA/CHP. Hospital de Santo António, Centro Hospitalar do Porto (HSA/CHP), Porto. Introdução A pressão de perfusão sanguínea da mucosa traqueal situa-se entre os 25-35mmHg/20-30cmH2O. Pressões superiores a 30 cmH2O podem gerar lesões na parede da traquéia como: estenose traqueal, perda do epitélio ciliado, hemorragia, ulceração e necrose. Por outro lado, pressões inferiores a 20 cmH2O, podem levar a broncoaspiração, tornando o doente susceptível a infecções respiratórias, um cuff pouco insuflado pode também provocar a fuga de ar em doentes ventilados artificialmente. Objectivos Identificar e analisar estudos empíricos que versem a temática da gestão da pressão intracuff em doentes traqueostomizados. Material e Métodos Revisão de literatura nas bases de dados: EBSCO, PUBMED, MEDSCAPE e Google Académico. As palavras-chave utilizadas foram: tracheostomy and cuff; tracheostomy tube cuff. Os critérios de inclusão foram: publicações em português e inglês, acesso livre, texto completo, no período de 2005-2011, num total de 71 artigos, foram incluídos apenas 14. Resultado A desinsuflação do cuff não é bem tolerada por muitos doentes, podendo resultar em aspiração. Quando insuflado protege a via aérea prevenindo a perda de ar, em doentes ventilados mecanicamente, e a broncoaspiração. No entanto, uma desinsuflação precoce do cuff na presença da peça em T reduz o esforço respiratório, é preferido em pacientes conscientes, beneficia a capacidade para falar e deglutir, acautelando-se que a capacidade para deglutir é cuidadosamente monitorizada e a acumulação de secreções supracuff é limitada para prevenir a aspiração. Quando a pressão do cuff é superior induz a isquemia/necrose. A lesão isquémica da traqueia depende da relação entre a pressão de perfusão da mucosa e a perfusão exercida pelo cuff. Relativamente aos estudos dos valores de monitorização da pressão intracuff verificam-se medidas irregulares, tanto acima quanto abaixo dos valores de segurança. Na rotina hospitalar, muitas vezes não há mensuração da pressão intracuff, ou esta é realizada de forma indirecta, através da palpação do balão externo, técnica extremamente inadequada. A utilização do cufómetro é a técnica recomendada pela literatura. Do mesmo modo, é aconselhada a sua verificação pelo menos uma vez por turno. Na maioria dos casos os procedimentos de manutenção do cuff são da exclusiva responsabilidade dos enfermeiros. Conclusões Valores de pressão abaixo ou acima dos recomendados são responsáveis por diversas complicações que convêm acautelar. A monitorização da pressão intracuff não é uma actividade de rotina e a sua gestão è realizada de forma variável, sendo o método mais utilizado o cufómetro. Apresentador: Álvara Silva, Enfermeira, Serviço de Traumatologia Craneo Encefálica (TCE), HSA/CHP

Early Portuguese meteorological measurements (18th century)

Natural proxies, documentary evidence and instrumental data are the only sources used to reconstruct past climates. In this paper, we present the 18th century meteorologists (either Portuguese or foreigners) who made the first observations at several sites in Continental Portugal, Madeira Island and Rio de Janeiro (Brazil), from 1749 until 1802. Information is given concerning observation site, variables observed, measurement period, methods of measurements and sources (both manuscript and printed). Some examples from the data usefulness are given: rainfall variability in Madeira (1749–1753) and in continental Portugal (1781–1793) was reconstructed, allowing to extend towards the late 18th century the well known negative correlation between the NAO index and seasonal rainfall. Furthermore, previously unpublished data for 1783–1784 have allowed analysing the consequences of the Lakagígar eruption in Portugal: foggy and haze days are referred to in summer 1783, but unlike the hot summer observed in northern and central Europe, temperatures in Portugal were lower than average. Additionally, observations from Rio de Janeiro in Brazil show that the Lakagígar consequences may well have spread to sectors of the Southern Hemisphere. Although the series are short, the data have been used for climate reconstruction studies and may also be useful to improve the quality of large scale reconstruction datasets.info:eu-repo/semantics/publishedVersio