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The present study aims to understand the process of turbulent entrainment into a jet, as affected by background turbulence, using scalar statistics. Planar laser-induced fluorescence was employed to capture the orthogonal cross sections of the jet at a fixed downstream station with varying background turbulence intensities and length scales. The conditional scalar profiles revealed that the thickness of the scalar turbulent/turbulent interface is greater than that of the traditional turbulent/non-turbulent interface, and the interfacial thickness is an increasing function of the background turbulence intensity. Although nibbling remains the primary entrainment mechanism in the far field, increased occurrence of concentration "holes" within the interfacial layer in the presence of ambient turbulence suggests a more significant role of large-scale engulfment in the turbulent/turbulent entrainment process (although still below 1% of the total mass flux). Enhanced contribution of the area of detached jet patches (i.e., "islands") to that of the main jet is hypothesized to be evidence of intense detrainment events in the background turbulence. This can potentially contribute to a reduced net entrainment into the jet, which manifests as less negative values of scalar skewness within the jet core. [ABSTRACT FROM AUTHOR]

The impact of turbulent coflows on the dynamics of turbulent twin round jets is investigated experimentally. Parallel twin jets, at three jet spacing values and two Reynolds number/jet-to-coflow velocity ratios, were released into turbulent coflows with two distinct levels of turbulence intensity. Velocity measurements were made using acoustic Doppler velocimetry. An increase in the coflow turbulence intensity leads to an earlier merging and combining of the jets and also accelerates the rate of decay with downstream distance of the mean centerline excess velocity of the jets. The mean velocity on the symmetry line, for different values of jet spacing, ratios of jet exit velocity to coflow mean velocity, and coflow turbulence intensity, is self-similar when scaled by the maximum mean velocity on the symmetry line and the corresponding streamwise distance. Moreover, as the turbulence level of the coflow intensifies, the turbulence intensity along the symmetry line of the jets increases. The longitudinal integral length scale on the symmetry line of the twin jets decreases as the coflow turbulence intensity increases. The energy spectra of the coflowing twin jets show that the turbulence in the coflow transfers the energy contained by the larger scales to the smaller scales at a greater rate than that which occurs for jets in a quiescent background. However, as the jet spacing increases, less energy is transferred to the smaller scales. [ABSTRACT FROM AUTHOR]

Planar laser-induced fluorescence is employed to investigate the concentration field in the developing region of a coaxial jet with an annular to inner jet velocity of one. Seeding the annular flow with a scalar shows that prior to the erosion of the inner scalar core, an inner interface exists, across which the scalar quantities exhibit sharp gradients akin to the traditional outer interface. Coarse grain filtering revealed that the outer interface establishes the universal fractal scaling before the onset of self-similarity, while the inner interface does not develop sufficient scale separation to do so due to the lack of shear. [ABSTRACT FROM AUTHOR]

Uganda's Vision 2040 aims to modernize rural water supply through a transition from community-managed point sources to professionally managed piped water services. At the start of the transition period, a learning alliance established in Kabarole District participated in action research to develop scenarios predicting possible future development trajectories. The diversity of its membership, whose formal institutional roles spanned national, district and niche levels, increased the robustness of the strategies proposed for the adaptively managed transition of the public water service. The learning alliance has been facilitated by a non-governmental organization providing funding and expert advice; the effectiveness of this approach is demonstrated. [ABSTRACT FROM AUTHOR]

The effect of a zero-mean-flow turbulent ambient on the geometry of the turbulent/turbulent interface (TTI) of an axisymmetric jet is investigated and compared with the traditional turbulent/non-turbulent interface (TNTI). The ambient turbulence is generated using a random jet array. Orthogonal cross-sections of the jet subjected to different levels of ambient turbulence intensities and length scales are captured using planar laser-induced fluorescence. The enhanced radial transport of concentration from the jet core towards the interface and the increased scalar fluctuations within the jet caused by the ambient turbulence result in steeper mean and root-mean-square scalar conditional jumps across the TTI layer compared with those of the TNTI, respectively. When compared with the quiescent ambient, the mean effect of background turbulence is to stretch and corrugate the interface surface area as evident from the wider probability density of the interface radial position, the lowered occurrence of zero-curvature surface elements, the greater misalignment between the radial and normal unit vectors of the interface, the increased tortuosity and the increased magnitude of the fractal exponent. [ABSTRACT FROM AUTHOR]

Abstract: Schemes to restore fish habitat in rivers often involve installing instream structures such as current deflectors to create and maintain riffle-pool sequences. However, there is a lack of field [...]

Wilson's disease (WD) is a hereditary disorder of copper metabolism, producing abnormally high levels of non-ceruloplasmin-bound copper, the determinant of the pathogenic process causing brain and hepatic damage and dysfunction. Although the disease is invariably fatal without medication, it is treatable and many of its adverse effects are reversible. Diagnosis is difficult due to the large range and severity of symptoms. A high index of suspicion is required as patients may have only a few of the many possible biomarkers. The genetic prevalence of ATP7B variants indicates higher rates in the population than are currently diagnosed. Treatments have evolved from chelators that reduce stored copper to zinc, which reduces the toxic levels of circulating non-ceruloplasmin-bound copper. Zinc induces intestinal metallothionein, which blocks copper absorption and increases excretion in the stools, resulting in an improvement in symptoms. Two meta-analyses and several large retrospective studies indicate that zinc is equally effective as chelators for the treatment of WD, with the advantages of a very low level of toxicity and only the minor side effect of gastric disturbance. Zinc is recommended as a first-line treatment for neurological presentations and is gaining acceptance for hepatic presentations. It is universally recommended for lifelong maintenance therapy and for presymptomatic WD. [ABSTRACT FROM AUTHOR]

The effect of approximately homogeneous isotropic turbulence on the dynamics of an axisymmetric turbulent jet (Re = 10 600 and 5800) in an ambient with a negligible mean flow is interpreted from the statistics of the passive scalar field. The ambient turbulence is generated by a random jet array and scalar concentrations are measured in orthogonal cross sections of the jet using planar laser-induced fluorescence. Statistics of the scalar field of the jet in a turbulent ambient are compared to those in a quiescent ambient, using classical Eulerian averages and those conditioned on the jet centroid. A two-region model for the jet structure in ambient turbulence is proposed based on the centroidal statistics. Following the developing region of the jet, the ambient turbulence disrupts the jet structure, due to modulation of the jet interface, meandering of the jet by large eddies, and entrainment of the turbulent ambient fluid, resulting in a faster concentration decay and reduced entrainment compared to the quiescent ambient. Further downstream, once the ambient turbulence has destroyed the jet, only molecular and turbulent diffusion modify the scalar concentrations. The regions' relative lengths depend primarily on the relative turbulence intensity (ξ) between the ambient and the jet, as assessed using centroidal analysis, which removes the effect of the relative length scale (l) on the jet behavior in the turbulent ambient. The centroidal scalar statistics reveal self-similarity and self-preservation in mean scalar properties before jet breakup, which occurs abruptly once ξ > 0.5. The smaller scales of ambient turbulence modulate the jet boundary and, when entrained, lead to a wider range of centerline concentrations and root mean square concentrations, which are hypothesized to increase local concentration gradients within the jet and reduce jet mixing. [ABSTRACT FROM AUTHOR]

The drinking water services sector in Uganda is in the early stages of a nationally planned transition; it aims to move from a paradigm based on community managed point sources towards one of professional utilities of piped networks. The implementation of this transition was studied in Western Uganda's Kabarole District between 2017 and 2019; a systems approach (building blocks) was used to assess the sustainability of the different service models. The level of services was assessed using household and infrastructure surveys; these were supplemented by a management assessment, key informant interviews and stakeholder workshops. The two utility models present in Kabarole outperformed the community management model, with the existing national utility demonstrating greater maturity and performance than the newer Umbrella utility. The community management model, while relatively well defined in policy and planning frameworks, was poorly implemented, with less than 20% of community management structures operational at water points. The water sector is undergoing a process of consolidation of service delivery under a smaller number of larger providers, a trend that has been observed in other countries as they progress towards universal supply. In this paper, the prospects and risks of the current sector trajectory are discussed, as are the implications for monitoring, regulation and planning systems across the urban-rural spectrum. [ABSTRACT FROM AUTHOR]

We consider the scalar concentration field in the proximity of the turbulent/non-turbulent interface (TNTI) of a round momentum-driven turbulent jet at Re = 10 600. Orthogonal cross sections of the jet are taken at 50 nozzle diameters from the nozzle exit using planar laser-induced fluorescence. The conditional scalar concentration is evaluated along the interface-normal direction, identifying the thickness of the TNTI region as 0.64λ (where λ is the Taylor microscale). Conditioning the scalar concentration within the TNTI revealed higher values of the passive scalar in the vicinity of the boundary elements shaped by large vorticity structures, i.e., isosurface points with low curvature (flat regions), small interface angle, and large radial distance from the jet centerline. In contrast, small vorticity structures near the boundary manifesting with high interface curvature, high interface angle, and small radial distance are associated with lower concentration values. Using the current experimental resolution, we find that high concentrations near the far boundary points persist up to a distance of 0.40λ–0.48λ into the TNTI region, after which boundary points closer to the jet centerline exhibit larger concentration values along the interface-normal direction, similar to the fully turbulent region. The cross correlation analysis showed that in regions characterized by low streamwise momentum, there are positive, albeit small, scalar correlations between the non-turbulent and the TNTI regions. The latter may imply local detrainment of the fluid particles containing the scalar at far radial positions. [ABSTRACT FROM AUTHOR]

Impact assessments on river systems of the combined effect of bed and suspended sediment loads from quarries are difficult to find. In this study, bed and suspended loads were measured to determine the impact of a 20-ha limestone quarry on the river system of its 5,000-ha steep, diverse land use/land cover but mostly forested catchment. A network of hydrologic and sediment monitoring instruments was deployed over the catchment during two separate study periods when sediment loadings were measured from captured storms. Results showed that the quarry stood to make a disproportionately large contribution to the catchment's estimated 2·1 Mg ha−1 yr−1 suspended sediment load. Large storm events contributed most of the loadings with five events supplying 92% of total loadings at the outlet. A paired method approach to compare suspended sediment loads between two subcatchments showed that during eight storm events, the quarry yielded between 2 and 49·2 Mg ha−1 per event, whereas the forest never yielded more than 0·1 Mg ha−1. Furthermore, the contribution of sediments from the quarry to bed load was more than 75% at a section located 1·2 km downstream. Future management activities to reduce sediment and bed loads, not only from this catchment but also from all others with similar land use/land covers, should focus on improving quarry operations. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

An ecomimetic method is developed as an innovative and transdisciplinary design approach rooted in the field of biomimetics. This new method emulates the interrelated complexity of the parts of an ecosystem with the intent to design buildings that are more efficient, effective and holistic. Ecomimetics refers to the design of buildings that mimic ecosystem processes and functions. This approach provides potential opportunities for climate change adaptation and mitigation by optimizing the use of resources in buildings. One challenge to the application of ecomimetics in architecture is the lack of systematic methods supported by scientific research, which may prevent development in this field. A theoretical basis and the initial development of an ecomimetic design method is presented, with a description of each step of the design process. Ecological systems are selected for functional properties that match architectural design goals, and then design tools are used to abstract and transfer those properties to architectural systems. The design tools integrated in the method are from the fields of ecological engineering, systems dynamics and architecture. The case of the Eastgate Center in Harare, Zimbabwe, is used to illustrate the method. [ABSTRACT FROM PUBLISHER]

A meshless method is used to simulate free-surface fluid flows containing solid particles, motivated by the need to simulate river ice dynamics problems. A smoothed particle hydrodynamics model (SPH), with an arbitrary Lagrangian–Eulerian formulation for the fluid phase, is two-way coupled with the discrete element method (DEM) for the solid phase. Validation test cases include a bouncing sphere on a level surface, a collapse of a granular column, wedge entry into still water and solids of different densities falling into still water. The computed results using the SPH-DEM model agree quantitatively with the expected behaviour in the test cases. Numerical convergence is demonstrated for the wedge entry validation case. The SPH-DEM model is then used to simulate the stability of floating ice blocks approaching a stationary cover and ice accumulation upstream of an obstruction. The results show promise to serve as a useful quantitative engineering tool. [ABSTRACT FROM PUBLISHER]

Engineers frequently use physical scale models of hydropower intakes to assess and minimize the occurrence of harmful free surface vortices. The impact of surface tension, viscosity and turbulence on the scaling behaviour of the vortices is examined here using an analytical free surface vortex model developed from measurements in a laboratory-scale hydropower intake. First, the effect of surface tension on the free surface depression is computed using a finite-difference model over a wide range of depression scales and shapes. The impact and scaling behaviour of surface tension are found to be qualitatively different depending on whether the depression is dimple- or funnel-shaped. The influence of viscosity on scaling predicted by the analytical vortex model contradicts trends recorded by previous authors, which suggests that additional processes such as turbulent diffusion may play a significant role at larger scales. Scale effects due to the interplay of viscosity and turbulence require further investigation, whereas those due to surface tension are fairly easily quantified and predicted. [ABSTRACT FROM AUTHOR]

Axially stretched free-surface vortices occur at low-head hydropower intakes under specific flow and geometric conditions. When they are sufficiently strong, they can harm performance or cause premature failure of mechanical components such as turbine blades or guide vanes. Laboratory-scale experimental models are currently used to assess the risk of vortex formation during the design phase, but uncertainty remains as to how vortex characteristics translate from the laboratory scale to the much larger scale of an actual hydropower plant. This paper proposes a semi-empirical model that roughly predicts how the approach flow and intake geometry determine the key vortex characteristics (the core radius, bulk circulation and the depth of the free surface depression). The model is developed using detailed velocity measurements of the approach flow and the flow inside the vortex in a laboratory-scale physical model, using analytical models and insights drawn from previous work. [ABSTRACT FROM AUTHOR]

Ecosystems biomimetics means learning from ecosystems; that is, learning from complex, resilient, selforganized systems in nature, and transferring valuable ecosystem patterns into the architectural work. However, the methodology is incipient and biomimetic tools have to cross disciplines to convey meaning for both ecology and architecture; so qualitative and quantitative tools need to be developed in order to stimulate the research in the field. In this paper, an ecological engineering tool, the energy systems diagrams as defined by ecologist H. Odum, is used to represent more than 20 sustainable-rated buildings under the light of ecological systems. The buildings selected are certified projects under the LEED, Living Building Challenge or Passive House rating systems, and data has been captured from their organizations web sites. The results show that ecological systems diagrams are powerful and effective instruments for characterization of the environmental performance of buildings in terms of energy and matter use; and that a shared language between disciplines is achievable. The validation of ecological systems diagrams as a useful biomimetic tool gives ground for further research on quantitative instruments to develop a complete methodology of ecosystems biomimetics. [ABSTRACT FROM AUTHOR]

To validate the use of acoustic Doppler velocimeters (ADVs) for the measurement of turbulent flows, experiments were conducted in an axisymmetric turbulent jet and in approximately homogenous isotropic turbulence with zero mean flow. The jet experiments show that the horizontal RMS velocities measured by the ADV were overestimated when compared to both flying hot-film anemometry measurements and the accepted values in the literature. However, the vertical component of the RMS velocity agrees well with those of other studies. This was furthermore confirmed by the ADV measurements in the isotropic turbulence with zero mean flow. Given that the overestimated RMS velocities in the horizontal directions may be caused by Doppler noise and spikes, two postprocessing filters and a Doppler noise-reduction method were applied to the jet data in an attempt to correct the data. Although the RMS velocities decreased, they remained erroneously higher than the accepted values. A noise-reduction method for axisymmetric flows that corrects the RMS velocities to within the range of acceptable values is presented. Lastly, because the Doppler noise is thought to depend on the mean velocity, a series of laboratory experiments were undertaken to relate Doppler noise to the mean velocity. The results showed no clear relationship between the Doppler noise and the mean flow. In addition, subtracting the Doppler noise (measured for a given mean velocity) from the measured RMS velocities (at the same mean velocity) did not significantly decrease the RMS velocities. [ABSTRACT FROM AUTHOR]

In sub-Saharan Africa, girls' daily household chores often involve fetching water for their households. This article addresses the impact of uncertain water access in semi-urban Cameroon given the problems of rapid urbanization and increasing demands for water. A school competition engaged youth and key water sector actors in a dialogue about the water crisis in Buea town, and this resulted in the publication of the water distribution schedule. The event also drew attention to the gendered implications of the crisis in relation to girls' sexual health. Our analysis suggests that girls fetching water face multiple layers of risk that include gender-based violence and blame resulting from the gendered stigma attached to young people's behavior-particularly that of girls. All this serves to increase the moral panic surrounding youth sexualities. We explicitly use the term sexualities (plural) here to recognize the multiple ways in which sexualities may be expressed, constructed and experienced (Arnfred 2005). This research points to the dire need to better understand and consider within water management strategies how girls cope with and confront these risks. [ABSTRACT FROM AUTHOR]

Trinidad and Tobago's 1.3 million residents are provided water supply and sewerage services by a national utility whose service levels have been inadequate and deteriorating through the recent past, largely due to a lack of investment in utility infrastructure. A “willingness to pay” study assessed the degree of coverage and quality of service and the residents' willingness to accept water tariff increases for an increase in service level. Willingness to pay for change is low, below current tariffs, due to scepticism about the likelihood of change and due to the ability to cope with bad service through the pervasive use of local storage. [ABSTRACT FROM AUTHOR]

The efficient use of water is necessary in water scarce regions like Barbados. This study provides an insight into the impact of two water demand management measures, water pricing and metering, on residential water use in Barbados. Econometric demand models of residential water use are developed to assess the potential of pricing policies to conserve water. The models are used as policy tools to investigate the impact of future increases in water price on water use and revenue generation, considering also the equity of price increases. Metering must be accompanied by a substantial increase in price to encourage water conservation. [ABSTRACT FROM AUTHOR]