Water utility of the future: a case study of conservation as a service

INTRODUCTION: Water utilities serving growing populations in dry climates face challenges in balancing increasing water demand with scarce supplies. New water supply sources are increasingly expensive and require construction of additional infrastructure for treatment and delivery. This poses a challenge for utilities to balance revenues and costs to remain financially viable. As a result, water utilities may face a difficult choice. If the utility chooses to develop new water supplies, they will have to increase their rates. However, they can also choose to assess alternative supply and demand management strategies to match revenues with the increasing marginal costs. Approaches such as water reuse, rainwater or condensate harvesting or harnessing other alternative sources are becoming increasingly widespread. Nonetheless, it is important to continuously assess and implement demand conservation programs, which often prove relatively quick, low-cost and straightforward to implement. [TRUNCATED

One Water strategies for New Braunfels Utilities

INTRODUCTION: In February of 2017, Boston University’s Institute for Sustainable Energy (ISE) and the Cynthia and George Mitchell Foundation (CGMF) initiated a multi-year project that aims to understand how water utilities in Texas cities can apply the principles of One Water to address the challenges of increasing urban populations, supply changes, and aging water infrastructure. Since summer 2018, the ISE team has engaged with New Braunfels Utility (NBU) to understand the opportunities relating to One Water for them as a mid-size utility serving a rapidly growing population. The One Water paradigm spans potable water, wastewater, and storm water, and considers opportunities for water sourcing, treatment, and use holistically. Discussions around One Water often focus on supply side strategies, such as how water reuse or rainwater harvesting can provide alternate sources of water. However, demand management and water conservation also play a role in One Water by promoting sustainability, resilience, and reducing the need for additional gray infrastructure. Ultimately, NBU may explore many strategies related to One Water. We chose to focus on demand reduction due to the utility’s concern over potentially large increases in New Braunfels’ water demand in the coming years. The ISE team analyzed meter-level data and also pumping data from NBU. We benchmarked NBU water demand, analyzed the demand by type of account, and identified the demand distribution by account. The findings led us to revisit projections of future water demand and generate a new demand projection that suggests demand growth may be slower than previously anticipated. While NBU’s supplies are more than sufficient to meet projected demand through 2030, there are other benefits to effective demand management and water conservation practices. Consequently, ISE developed recommendations for a targeted outreach program to high consumers and to promote rebates to developers. We also drafted ordinance revisions related to watering violations

Multiparameter Shape Optimization

Optimization tools in engineering design often require a high computational cost. This cost originates from two main sources: First, the evaluation of the objective function involved in such problems is in general very expensive. Then, depending on the method employed and on the dimension of the design vector, the optimization procedure requires a high number of evaluations of the objective function to reach the final solution. Many authors proposed hierarchical techniques to make the optimization algorithm cheaper. Among these techniques, we can cite the use of a simplified model of the physical problem (for exemple, the use of Euler equations instead of the Navier-Stokes ones), the use of a metamodel instead of the exact model, or the use of a hierarchical parameterization instead of a single level one. This means that the optimization is carried out, at some steps, on a coarse level where not all the design parameters are considered. This idea is inspired from the multigrid theory used to solve problems with differential equations. In the present study, we propose a more efficient and more general method that can accelerate the convergence of the optimization algorithm and can be employed for any kind of problem. This method combines the multigrid concept with the spectral decomposition of the Hessian matrix of the cost function. Indeed, the smallest eigenvalues of the Hessian matrix correspond to directions where the convergence of the optimization algorithm is very slow, while the highest eigenvalues correspond to directions where the convergence is fast when descent optimization algorithms are used. Thus, instead of iterating on the entire design space, our algorithm serach for the solution in a selected subspace in order to accelerate the resolution in the directions of low convergence rate. Then it pursues the search on the entire design space. This can be done by several strategies analogous to those of the multigrid methods

A non-destructive technique for the on-line quality control of green and baked anodes

Carbon anodes play an important role in the electrolytic production of aluminum. They have a significant economic and environmental impact. Carbon anodes are made of dry aggregates, composed of petroleum coke, recycled rejects, and butts, bound by coal tar pitch. Due to several factors, defects (cracks/pores) appear in anodes during the fabrication process, affecting their quality. It is thus essential to control the quality of anodes before their use in the electrolysis cell. Current practice for the quality evaluation (visual inspection, core analysis) gives limited information. As an alternative to this practice, electrical resistivity measurements can be used. Electrical resistivity is one of the key indicators for anode quality and its homogeneity. A simple and non-destructive method has been developed for the specific electrical resistivity measurement of anodes (SERMA) for on-line control of anode quality. Various tests have been carried out at both lab scale and industrial scale. In this study, the electrical resistivity distributions in the lab-scale anodes were measured and compared with those of the tomography analysis. The method is able to detect defective anodes even before the baking process

Efficient Hierarchical Optimization using an Algebraic Multilevel Approach

This paper presents an efficient method to reduce the optimization cost. In this method, the eigenvectors of the Hessian of the objective function are determined first. Then, the search for the optimum is carried out successively in subspaces defined by these vectors. For this purpose, the Multi-directional-Search Algorithm is used in this study, but any other optimization algorithm can be employed. The method is validated in two test cases: analytical function and shape reconstruction problem. In both cases, this method shows very promising results

Méthode algébrique pour l'optimisation multiniveau - Application à l'optimisation d'un avion d'affaires supersonique

International audienceDans cet article, nous proposons une approche multiniveau permettant d'accélérer les algorithmes d'optimisation classiques. Cette approche utilise les vecteurs propres de la matrice Hessienne de la fonction coût pour définir des sous-espaces de conception. La recherche de l'optimum est alors effectuée successivement dans ces sous-espaces de dimension variable. La méthode proposée est validée sur un problème de reconstruction de forme, puis appliquée à l'optimisation d'un avant projet d'avion d'affaires supersonique

La transmission des langues d’origine dans les familles récemment immigrées en France : pour une prise en compte de l’héritage plurilingue

Dieser Beitrag behandelt die Sprachübertragung von Minderheitensprachen oder Herkunfts­sprachen von ZuwanderInnen in Frankreich. Im ersten Teil des Beitrags erörtern wir das Bilingualismus-Vorurteil, das die Forschung über MigrantInnensprachen kennzeichnet: Dieses geht von idealen zweisprachigen MigrantInnen aus, die einerseits ihre minorisierte Herkunfts­sprache bewahren und andererseits die offizielle Landessprache ihres Aufnahme­landes beherrschen. Es gibt jedoch keinen Grund zu der Annahme, dass ZuwanderInnen, die oft aus bekanntermaßen hochmehrsprachigen Ländern kommen, bei ihrer Ankunft ein­sprachig sein müssen. Im zweiten Teil legen wir eine kleine Fallstudie über zwei außer­europäische Zuwandererfamilien vor, die kürzlich in Frankreich angekommen sind, eine aus dem Tschad und die andere aus die Türkei. Unsere empirische Studie mittels teil­strukturierter Befragungen zeigt insbesondere eine große Heterogenität der sprachlichen Repertoires, der Ideologien und des Sprachwahlverhaltens zwischen und innerhalb der beiden Familien. Der „One-Parent-One-Language“-Ansatz ist offensichtlich nicht relevant; die Eltern berichten, dass sie im Laufe der Zeit eine Reihe von Sprachwahlmustern kombinieren, die sie mit ihren Kindern praktizieren, die alle unausgewogene Sprachen­repertoires entwickelt haben, die mehrere der Herkunfts­sprachen ihrer Eltern kombinieren. Unsere Studie zeigt die Notwendigkeit, bei der Forschung zu MigrantInnen­sprachen auf vielfältigere und ausdrücklich mehrsprachige Forschungsansätze zurückzugreifen.This paper deals with the transmission of immigration minority or heritage languages in France. First, we bring to light a bilingual bias in the research on immigration languages which continues to represent ideal immigrant speakers as bilingual people maintaining their minorized heritage language on the one hand and speaking the official state language of their host society on the other hand. There is, however, no reason to believe that immigrants who often come from countries known to be highly multilingual should have been monolingual before their arrival. Then, we present a small case study on two extra-European families that recently arrived in France, one coming from Tchad and the other from Turkey. Based on semi-structured interviews, our empirical study predominantly reveals a great heterogeneity of language repertoires, ideologies and communication choices between and within both families. The One Person One Language approach is clearly not relevant and the parents report using varied and evolving linguistic strategies when interacting with their children, who have all developed unbalanced language repertoires in several of their parents’ heritage languages. Thus, our study calls for more diverse and explicitly multilingual research approaches to immigrant language speakers

Multiparameter Shape Optimization

Optimization tools in engineering design often require a high computational cost. This cost originates from two main sources: First, the evaluation of the objective function involved in such problems is in general very expensive. Then, depending on the method employed and on the dimension of the design vector, the optimization procedure requires a high number of evaluations of the objective function to reach the final solution. Many authors proposed hierarchical techniques to make the optimization algorithm cheaper. Among these techniques, we can cite the use of a simplified model of the physical problem (for exemple, the use of Euler equations instead of the Navier-Stokes ones), the use of a metamodel instead of the exact model, or the use of a hierarchical parameterization instead of a single level one. This means that the optimization is carried out, at some steps, on a coarse level where not all the design parameters are considered. This idea is inspired from the multigrid theory used to solve problems with differential equations. In the present study, we propose a more efficient and more general method that can accelerate the convergence of the optimization algorithm and can be employed for any kind of problem. This method combines the multigrid concept with the spectral decomposition of the Hessian matrix of the cost function. Indeed, the smallest eigenvalues of the Hessian matrix correspond to directions where the convergence of the optimization algorithm is very slow, while the highest eigenvalues correspond to directions where the convergence is fast when descent optimization algorithms are used. Thus, instead of iterating on the entire design space, our algorithm serach for the solution in a selected subspace in order to accelerate the resolution in the directions of low convergence rate. Then it pursues the search on the entire design space. This can be done by several strategies analogous to those of the multigrid methods

Review and Analysis of some Metamodeling Techniques used in Optimization

This papers aims at presenting a review of some metamodels used in optimization. We are interested in particular in the Radial Basis Functions and Kriging metamodels. The theory of these techniques is presented and their implementation is discussed. We present also the differentiation of these metamodels. Furthermore, a slight comparison between Radial Basis Functions and Kriging metamodels is given in ordrer to show their similarities and differences

Effect of Different Near-Wall Treatments on Indoor Airflow Simulations

Airflow simulation results depend on a good prediction of near wall turbulence. In this paper a comparative study between different near wall treatments is presented. It is applied to two test cases in building: (1) the first concerns flow through a long corridor which is similar to that in a fully developed plane channel. Simulation results are compared to direct numerical simulation (DNS) data of Moser et al. (1999) for Reτ = 590 (where Reτ denotes the friction Reynolds number defined by friction velocity uτ , kinematics viscosity ν and the channel half-width δ); (2) the second case is a benchmark test for room air distribution. Simulation results are compared to experimental data obtained with laser-Doppler anemometry (Nielsen, 1990). Simulations were performed with the aid of CFD code Fluent (2005). Near wall treatments available in Fluent were tested: Standard Wall Functions, Non Equilibrium Wall Function and Enhanced Wall Treatment. In each case, suitable meshes with adequate position of the first near-wall node are needed. Results of near-wall mean stream wise velocity u+ and turbulent kinetic energy k+ profiles are presented, variables with the superscript of + are those non dimensional by the wall friction velocity uτ and the kinematic viscosity ν