Numerical and experimental approaches to estimate discharge coefficients and energy loss coefficients in pressurized grated inlets

Numerical models concerning inlet systems are run to assess the hydraulic performance of existing or new systems and estimate the flow interchanges between the surface overland and sewer flows. In most programs, these interactions are modelled using the orifice equation, with estimated discharge coefficients around 0.6. In this paper, discharge values and energy loss coefficients for several pressurized grated inlets were obtained by experimental and numerical approaches and compared. To achieve these goals, a numerical model replicating several experimental tests carried out at the hydraulic laboratory of Universitat Politècnica de Catalunya (UPC) was produced using a CFD model (Flow 3D). This numerical model was found to be highly sensitive to the mesh size used; however, it was able to accurately simulate the experimental processes. The comparison considered different combinations of pressurized flow though the grate, between 10 to 50 l/s, and different longitudinal gradients. The experimental discharge coefficient was found to increase with surcharging flowrate (ranging from 0.14 and 0.41), whereas the longitudinal gradient was found to have no effect. The discharge coefficients obtained in this study show that the standard 0.6 value commonly used by practitioners should be revised to a range between 0.14 to 0.41, depending on circulating flow and inlet type. In addition, the loss coefficient values range from 0.25 to 3.41. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Biodesalination: an emerging technology for targeted removal of Na+and Cl−from seawater by cyanobacteria

Although desalination by membrane processes is a possible solution to the problem of freshwater supply, related cost and energy demands prohibit its use on a global scale. Hence, there is an emerging necessity for alternative, energy and cost-efficient methods for water desalination. Cyanobacteria are oxygen-producing, photosynthetic bacteria that actively grow in vast blooms both in fresh and seawater bodies. Moreover, cyanobacteria can grow with minimal nutrient requirements and under natural sunlight. Taking these observations together, a consortium of five British Universities was formed to test the principle of using cyanobacteria as ion exchangers, for the specific removal of Na+ and Cl− from seawater. This project consisted of the isolation and characterisation of candidate strains, with central focus on their potential to be osmotically and ionically adaptable. The selection panel resulted in the identification of two Euryhaline strains, one of freshwater (Synechocystis sp. Strain PCC 6803) and one of marine origin (Synechococcus sp. Strain PCC 7002) (Robert Gordon University, Aberdeen). Other work packages were as follows. Genetic manipulations potentially allowed for the expression of a light-driven, Cl−-selective pump in both strains, therefore, enhancing the bioaccumulation of specific ions within the cell (University of Glasgow). Characterisation of surface properties under different salinities (University of Sheffield), ensured that cell–liquid separation efficiency would be maximised post-treatment, as well as monitoring the secretion of mucopolysaccharides in the medium during cell growth. Work at Newcastle University is focused on the social acceptance of this scenario, together with an assessment of the potential risks through the generation and application of a Hazard Analysis and Critical Control Points plan. Finally, researchers in Imperial College (London) designed the process, from biomass production to water treatment and generation of a model photobioreactor. This multimodal approach has produced promising first results, and further optimisation is expected to result in mass scaling of this process

Water use and water availability constraints to decarbonised electricity systems

Analysis of numerous low carbon electricity strategies have been shown to have very divergent water requirements, normally needed for cooling of thermoelectric power stations. Our regional river-basin scale analysis of water use for future UK electricity strategies shows that, whilst in the majority of cases freshwater use is expected to decline, pathways with high levels of carbon capture and storage (CCS) will result in significantly elevated and concentrated water demands in a few key river basins. Furthermore, these growing demands are compared to both current water availability, and our expected regional water availability under the impacts of climate change. We identify key freshwater constraints to electricity strategies with high levels of CCS and show how these risks may be mitigated with higher levels of hybrid cooling and alternative cooling water sources

Seguridad de la sedación profunda con propofol controlada por el endoscopista en la colangiopancreatografía retrógrada endoscópica (CPRE). Estudio prospectivo en un hospital terciario

Introducción: el propofol, administrado por el endoscopista con una enfermera entrenada, ha evolucionado como alternativa a la monitorización anestésica y es cada vez más frecuente en la práctica clínica habitual, incluso en endoscopia avanzada. Objetivo: evaluar la seguridad de la sedación profunda con propofol controlada por el endoscopista en pacientes sometidos a colangiopancreatografía retrógrada endoscópica (CPRE). Material y métodos: estudio prospectivo en los pacientes a los que se les realizó CPRE bajo sedación profunda con propofol. Se incluyeron diferentes variables relacionadas con el paciente y se registraron los datos iniciales y finales de la saturación de oxígeno (SatO2), la tensión arterial (TA), y la frecuencia cardiaca (FC) para determinar la presencia de eventos adversos a la sedación (hipoxemia, hipotensión o bradicardia). Resultados: un total de 661 pacientes fueron sometidos a CPRE bajo sedación con propofol durante un periodo de 24 meses. La tasa de eventos adversos registrada fue del 9, 7%. La más frecuente fue la hipoxemia (5, 7%), seguida de la bradicardia (2, 4%) y de la hipotensión (1, 6%). En el análisis univariante, la aparición de eventos adversos a la sedación (EAS) se asoció a una clasificación de ASA = III (p = 0, 026), a pacientes de edad más avanzada (p = 0, 009), mayor IMC (p = 0, 002) y a un tiempo de exploración más prolongado (p = 0, 034). La dosis de inducción de propofol también se relacionó con mayor probabilidad de eventos adversos (p = 0, 045), pero no la dosis total de propofol administrado (p = 0, 153). En el análisis de regresión logística multivariante, la edad, el índice de masa corporal (IMC) y la duración de la exploración se registran como predictores independientes de EAS (p < 0, 05). Conclusión: la sedación profunda con propofol controlada por personal de endoscopia entrenado es un método seguro en procedimientos endoscópicos complejos como la CPRE. Introduction: propofol administered by an endoscopist with a trained nurse has evolved as an alternative to anesthesia monitoring and is increasingly common in the routine clinical practice, even in advanced endoscopy. Objective: to evaluate the safety of deep sedation with endoscopist-controlled propofol in patients undergoing endoscopic retrograde cholangiopancreatography (ERCP). Material and methods: this was a prospective study in patients undergoing ERCP under deep sedation with propofol. Different patient-related variables were included and the initial and final data on oxygen saturation (SatO(2)) blood pressure (BP) and heart rate (HR) were recorded in order to determine the presence of adverse events due to sedation (hypoxemia, hypotension, or bradycardia). Results: a total of 661 patients underwent ERCP under sedation with propofol over a 24-month period. The rate of recorded adverse events was 9.7%. The most frequent adverse event was hypoxemia (5.7%), followed by bradycardia (2.4%) and hypotension (1.6%). According to the univariate analysis, the occurrence of adverse events due to sedation (AES) was associated with an ASA score >= III (p = 0.026), older patients (p = 0.009), higher body mass index (BMI) (p = 0.002) and a longer exploration time (p = 0.034). The induction dose of propofol was also associated with a greater likelihood of adverse events (p = 0.045) but not the total dose of propofol administered (p = 0.153). According to the multivariate logistic regression analysis, age, body mass index (BMI) and the duration of the exploration were independent predictors of SAE (p < 0.05). Conclusion: deep sedation with propofol controlled by trained endoscopy staff is a safe method in complex endoscopic procedures such as ERCP

Emergence and Spread of Streptococcus pneumoniae with erm(B) and mef(A) Resistance

Streptococcus pneumoniae isolates (N = 31,001) were collected from patients with community-acquired respiratory tract infections during the PROTEKT US surveillance study (2000–2003). While the macrolide (erythromycin) resistance rate remained stable at ≈29%, the prevalence of resistant isolates containing both erm(B) and mef(A) increased from 9.7% in year 1 to 16.4% in year 3, with substantial regional variability. Almost all (99.2%) dual erm(B)+mef(A) macrolide-resistant isolates exhibited multidrug resistance, whereas 98.6% and 99.0% were levofloxacin- and telithromycin-susceptible, respectively. These strains were most commonly isolated from the ear or middle-ear fluid of children. Of 152 representative erm(B)+mef(A) isolates, >90% were clonally related to the multidrug-resistant international Taiwan19F-14 clonal complex 271 (CC271). Of 366 erm(B)+mef(A) isolates from the PROTEKT global study (1999–2003), 83.3% were CC271, with the highest prevalence seen in South Africa, South Korea, and the United States. This study confirms the increasing global emergence and rapidly increasing US prevalence of this multidrug-resistant pneumococcal clone