44 research outputs found

    A Model for Selecting the Most Cost-Effective Pressure Control Device for More Sustainable Water Supply Networks

    Get PDF
    Pressure Reducing Valves (PRV) have been widely used as a device to control pressure at nodes in water distribution networks and thus reduce leakages. However, an energy dissipation takes place during PRV operation. Thus, micro-hydropower turbines and, more precisely, Pump As Turbines (PAT) could be used as both leakage control and energy generating devices, thus contributing to a more sustainable water supply network. Studies providing clear guidelines for the determination of the most cost-effective device (PRV or PAT) analysing a wide database and considering all the costs involved, the water saving and the eventual power generation, have not been carried out to date. A model to determine the most cost-effective device has been developed, taking into account the Net Present Value (NPV). The model has been applied to two case studies: A database with 156 PRVs sites located in the UK; and a rural water supply network in Ireland with three PRVs. The application of the model showed that although the investment cost associated to the PRV installation is lower in the majority of cases, the NPV over the lifespan of the PAT is higher than the NPV associated with the PRV operation. Furthermore, the ratio between the NPV and the water saved over the lifespan of the PAT/PRV also offered higher values (from 6% to 29%) for the PAT installation, making PATs a more cost-effective and more sustainable means of pressure control in water distribution networks. Finally, the development of less expensive turbines and/or PATs adapted to work under different flow-head conditions will tip the balance toward the installation of these devices even further

    Responding to the UN sustainability goals in transdisciplinary partnership through network action learning

    Get PDF
    The global water crisis, an enormous concern according to the World Economic Forum, poses a significant challenge to long-term sustainability, exacerbated by the high energy demand associated with water supply and treatment. As the renewable energy sector grows, the need for green technologies to support the water-energy nexus becomes evident. However, mere technological advancements are insufficient to address complex water-related challenges. This paper presents a transdisciplinary collaborative effort involving engineers, geographers, management researchers, and environmentalists working with practitioners in a cross-border network. The study explores through action learning research how, in a transdisciplinary partnership, network action learning influences the exploration and implementation of novel green technology and the development of innovation capabilities. The research is structured around three themes: green technology platforms, policy support and guidance, and dissemination and collaboration. It identifies the factors impacting technology exploration and application and how concurrently green innovation capabilities are developed. The study emphasizes the significance of transdisciplinary collaboration and offers valuable insights into addressing UN Sustainability Goals related to clean water, sustainable industry, and partnerships. It contributes to innovation capability theory and provides practical guidance to researchers, practitioners, and policymakers, emphasizing the need for holistic approaches to address the water-energy crisis and achieve sustainable development

    Analysis of emerging technologies in the hydropower sector

    Get PDF
    The paper reviews recent research and development activities in the field of hydropower technology. It covers emerging and advanced technologies to mitigate flow instabilities (active and passive approach) as well as emerging magneto-rheological control techniques. Recent research findings on flow instabilities are also presented, especially concerning fluid-structure interaction and transient operating conditions. As a great number of the existing large-scale hydroelectric facilities were constructed decades ago using technologies that are now considered obsolete, technologies to achieve the digitalisation of hydropower are also analysed. Advances in the electro-mechanical components and generator design are presented; their potential role to adapt hydropower to the current operating conditions is also highlighted. The text explores current efforts to advance hydropower operation, mainly in terms of European projects. It provides a detailed overview of the recent efforts to increase the operational range of hydraulic turbines in order to reach exceptional levels of flexibility, a topic of several recent research projects. Variable speed hydropower generation and its application in pumped storage power plants are presented in detail. Moreover, revolutionary concepts for hydroelectric energy storage are also presented with the analysis focusing on underwater hydro storage and hydropower's hybridisation with fast energy storage systems. Efforts to minimise hydropower's environmental footprint are also presented via the utilisation of small-scale and fish-friendly installations

    Changes in renal function after nephroureterectomy for upper urinary tract carcinoma: analysis of a large multicenter cohort (Radical Nephroureterectomy Outcomes (RaNeO) Research Consortium)

    Get PDF
    Purpose To investigate prevalence and predictors of renal function variation in a multicenter cohort treated with radical nephroureterectomy (RNU) for upper tract urothelial carcinoma (UTUC). Methods Patients from 17 tertiary centers were included. Renal function variation was evaluated at postoperative day (POD)-1, 6 and 12 months. Timepoints differences were Delta 1 = POD-1 eGFR - baseline eGFR; Delta 2 = 6 months eGFR - POD-1 eGFR; Delta 3 = 12 months eGFR - 6 months eGFR. We defined POD-1 acute kidney injury (AKI) as an increase in serum creatinine by >= 0.3 mg/dl or a 1.5 1.9-fold from baseline. Additionally, a cutoff of 60 ml/min in eGFR was considered to define renal function decline at 6 and 12 months. Logistic regression (LR) and linear mixed (LM) models were used to evaluate the association between clinical factors and eGFR decline and their interaction with follow-up. Results A total of 576 were included, of these 409(71.0%) and 403(70.0%) had an eGFR < 60 ml/min at 6 and 12 months, respectively, and 239(41.5%) developed POD-1 AKI. In multivariable LR analysis, age (Odds Ratio, OR 1.05, p < 0.001), male gender (OR 0.44, p = 0.003), POD-1 AKI (OR 2.88, p < 0.001) and preoperative eGFR < 60 ml/min (OR 7.58, p < 0.001) were predictors of renal function decline at 6 months. Age (OR 1.06, p < 0.001), coronary artery disease (OR 2.68, p = 0.007), POD-1 AKI (OR 1.83, p = 0.02), and preoperative eGFR < 60 ml/min (OR 7.80, p < 0.001) were predictors of renal function decline at 12 months. In LM models, age (p = 0.019), hydronephrosis (p < 0.001), POD-1 AKI (p < 0.001) and pT-stage (p = 0.001) influenced renal function variation (ss 9.2 +/- 0.7, p < 0.001) during follow-up. Conclusion Age, preoperative eGFR and POD-1 AKI are independent predictors of 6 and 12 months renal function decline after RNU for UTUC

    Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

    Get PDF
    Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research
    corecore