252 research outputs found

    Urban rainwater harvesting systems: Research, implementation and future perspectives.

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    Published onlineJournal ArticleReviewThis is the author accepted manuscript. The final version is available from IWA Publishing via the DOI in this record.While the practice of rainwater harvesting (RWH) can be traced back millennia, the degree of its modern implementation varies greatly across the world, often with systems that do not maximize potential benefits. With a global focus, the pertinent practical, theoretical and social aspects of RWH are reviewed in order to ascertain the state of the art. Avenues for future research are also identified. A major finding is that the degree of RWH systems implementation and the technology selection are strongly influenced by economic constraints and local regulations. Moreover, despite design protocols having been set up in many countries, recommendations are still often organized only with the objective of conserving water without considering other potential benefits associated with the multiple-purpose nature of RWH. It is suggested that future work on RWH addresses three priority challenges. Firstly, more empirical data on system operation is needed to allow improved modelling by taking into account multiple objectives of RWH systems. Secondly, maintenance aspects and how they may impact the quality of collected rainwater should be explored in the future as a way to increase confidence on rainwater use. Finally, research should be devoted to the understanding of how institutional and socio-political support can be best targeted to improve system efficacy and community acceptance

    Global well-posedness of the Kirchhoff equation and Kirchhoff systems

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    This article is devoted to review the known results on global well-posedness for the Cauchy problem to the Kirchhoff equation and Kirchhoff systems with small data. Similar results will be obtained for the initial-boundary value problems in exterior domains with compact boundary. Also, the known results on large data problems will be reviewed together with open problems.Comment: arXiv admin note: text overlap with arXiv:1211.300

    Neurological assessment of very low birth weight infants with bronchopulmonary dysplasia

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    OBJECTIVE: To compare the neurological assessment of preterm newborn infants with and without bronchopulmonary dysplasia (BPD). METHODS: Preterm newborn infants with birth weight less than 1,500g and gestational age less than 32 weeks were evaluated by Dubowitz Method at 40 weeks of corrected gestational age. All infants were assisted at Universidade Estadual de Campinas (Unicamp), Campinas (SP), Brazil. Dubowitz Neurological Assessment comprised 29 items divided into six categories: tone, tone patterns, reflexes, movements, abnormal signs and behavior. Newborn behavioral state was graded in six degrees according to Brazelton (1973). Chi-square and Fisher exact tests were used for qualitative variables and Mann-Whitney for non-parametric numeric variables, with 5% significance level. RESULTS: From January of 2005 to September of 2007, 24 newborns were evaluated: 12 with BPD (mean gestational age and birth weight of 28±1 week and 884±202g) and 12 without BPD (31±1 week and 1156±216g). Out of the 29 items, 18 were homogeneous between the groups. The general score of the groups were similar (p=0.30). For eight items, BPD Group presented higher percentage of abnormalities. Infants without BPD had more abnormalities in three items. CONCLUSIONS: Dubowitz Neurological Assessment in preterm newborn infants with and without BPD did not present significant differences at 40 weeks of corrected gestational age. For reflex and posture/tone categories, there was a trend towards the presence of more abnormalities in the BPD Group.OBJETIVO: Descrever e comparar a avaliação neurológica e comportamental de recém-nascidos pré-termos com e sem displasia broncopulmonar (DBP). MÉTODOS: Recém-nascidos prematuros com peso ao nascer inferior a 1500g e idade gestacional menor de 32 semanas foram avaliados com 40 semanas de idade gestacional corrigida, no Centro de Atenção Integral à Saúde da Mulher da Universidade Estadual de Campinas. Utilizou-se a Avaliação Neurológica de Dubowitz, com 29 itens divididos em seis categorias: tônus, padrões de tônus, reflexos, movimentos, sinais anormais e comportamento. O estado de consciência do recém-nascido foi graduado segundo Brazelton (1973). Utilizaram-se os testes do qui-quadrado e exato de Fischer para variáveis qualitativas e o de Mann-Whitney para as numéricas não-paramétricas, com nível de significância de 5%. RESULTADOS: No período de janeiro de 2005 a setembro de 2007, 24 recém-nascidos, 12 com DBP e 12 controles, com idade gestacional ao nascer de 28±1 semana e peso de 884±202g no grupo com DBP e 31±1 semana e 1156±216g no Grupo Controle foram avaliados. Dos 29 itens avaliados, 18 foram homogêneos entre os grupos e a pontuação geral dos dois grupos não apresentou diferença (p=0,30). Observou-se maior anormalidade neurológica no grupo com DBP em oito itens e, no Grupo Controle, em três itens. CONCLUSÕES: A comparação da avaliação neurológica de Dubowitz de recém-nascidos pré-termos com e sem DBP não apresentou diferença significante com 40 semanas de idade gestacional corrigida. Nas categorias reflexos e postura/tônus, observou-se tendência a anormalidade no grupo DBP.212

    Cardiac rehabilitation a global perspective on where we have come and where we must go

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    Impact of system factors on the water saving efficiency of household grey water recycling

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    Copyright © 2010 Taylor & Francis. This is an Author's Accepted Manuscript of an article published in Desalination and Water Treatment Volume 24, Issue 1-3 (2010), available online at: http://www.tandfonline.com/10.5004/dwt.2010.1542A general concern when considering the implementation of domestic grey water recycling is to understand the impacts of system factors on water saving efficiency. Key factors include household occupancy, storage volumes, treatment capacity and operating mode. Earlier investigations of the impacts of these key factors were based on a one-tank system only. This paper presents the results of an investigation into the effect of these factors on the performance of a more realistic ‘two tank’ system with treatment using an object based household water cycle model. A Monte-Carlo simulation technique was adopted to generate domestic water appliance usage data which allows long-term prediction of the system's performance to be made. Model results reveal the constraints of treatment capacity, storage tank sizes and operating mode on percentage of potable water saved. A treatment capacity threshold has been discovered at which water saving efficiency is maximised for a given pair of grey and treated grey water tank. Results from the analysis suggest that the previous one-tank model significantly underestimates the tank volumes required for a given target water saving efficiency

    A regularity class for the roots of nonnegative functions

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    We investigate the regularity of the positive roots of a non-negative function of one-variable. A modified H\"older space Fβ\mathcal{F}^\beta is introduced such that if f∈Fβf\in \mathcal{F}^\beta then fα∈Cαβf^\alpha \in C^{\alpha \beta}. This provides sufficient conditions to overcome the usual limitation in the square root case (α=1/2\alpha = 1/2) for H\"older functions that f1/2f^{1/2} need be no more than C1C^1 in general. We also derive bounds on the wavelet coefficients of fαf^\alpha, which provide a finer understanding of its local regularity.Comment: 12 page

    Financial feasibility of end-user designed rainwater harvesting and greywater reuse systems for high water use households

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    © 2017, The Author(s). Water availability pressures, competing end-uses and sewers at capacity are all drivers for change in urban water management. Rainwater harvesting (RWH) and greywater reuse (GWR) systems constitute alternatives to reduce drinking water usage and in the case of RWH, reduce roof runoff entering sewers. Despite the increasing popularity of installations in commercial buildings, RWH and GWR technologies at a household scale have proved less popular, across a range of global contexts. For systems designed from the top-down, this is often due to the lack of a favourable cost-benefit (where subsidies are unavailable), though few studies have focused on performing full capital and operational financial assessments, particularly in high water consumption households. Using a bottom-up design approach, based on a questionnaire survey with 35 households in a residential complex in Bucaramanga, Colombia, this article considers the initial financial feasibility of three RWH and GWR system configurations proposed for high water using households (equivalent to >203L per capita per day). A full capital and operational financial assessment was performed at a more detailed level for the most viable design using historic rainfall data. For the selected configuration (‘Alt 2’), the estimated potable water saving was 44% (equivalent to 131m3/year) with a rate of return on investment of 6.5% and an estimated payback period of 23years. As an initial end-user-driven design exercise, these results are promising and constitute a starting point for facilitating such approaches to urban water management at the household scale
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