89 research outputs found
Water and Energy Saving in Urban Water Systems: The ALADIN Project
No full textAbstractThe ALADIN project was aimed at contributing to environmental and energy sustainability of the urban water system by means of a decision support tool able to allow an evaluation of the energy impact related to each different macro-sectors of urban water cycle highlighting the main energy flows and to assess the system energy balance and identify the possible energy-efficient solutions. Moreover the tool suggests the most efficient actions in reducing water losses. In the present paper the main features of the developed tool are presented
A continental-scale chironomid training set for reconstructing Arctic temperatures
No full textWe present chironomid species assemblage data from 402 lakes across northern North America, Greenland, Iceland, and Svalbard to inform interpretations of Holocene subfossil chironomid assemblages used in paleolimnological reconstruction. This calibration-set was developed by re-identifying and taxonomically harmonizing chironomids in previously described surface sediment samples, with identifications made at finer taxonomic resolution than in original publications. The large geographic coverage of this dataset is intended to provide climatic analogues for a wide range of Holocene climates in the northwest North Atlantic region and North American Arctic, including Greenland. For many of these regions, modern calibration data are sparse despite keen interest in paleoclimate reconstructions from high latitudes. A suite of chironomid-based temperature models based upon this training set are evaluated here and the best statistical model is used to reconstruct late glacial (Allerød and Younger Dryas) and Holocene paleotemperatures at five non-glacial lakes representing a wide range of climate zones across Greenland. The new continent-scale training set offers more analogues for the majority of Greenland subfossil assemblages than existing smaller training sets, with many in Iceland and northern Canada. We find strong agreement between chironomid-based reconstructions derived from the new model and independent glacier-based evidence for multi-millennial Holocene temperature trends. Some of the new Holocene reconstructions are very similar to published data, but at a subset of sites and time periods we find improved paleotemperature reconstructions attributable both to the new model's finer taxonomic resolution and to its expanded geographic/climatic coverage, which resulted in improved characterization of species optima. In the late glacial, the new model's finer taxonomic resolution yields a unique ability to resolve temperatures of the Allerød from colder temperatures of the Younger Dryas, although the magnitude of that temperature difference may be underestimated. This study demonstrates the value of geographically and climatically broad paleoecological training sets. The large, taxonomically harmonized dataset presented here should be useful for a wide range of future investigations, including but not limited to paleotemperature reconstructions across the Arctic
Catholic Comments Podcast.
No full textTheologian and author Mark Chimiel discusses his work “The Book of Mev” and the legacy of his late wife Mev Puleo
ACHIEVEMENT GOALS AND ENGAGEMENT OUTCOMES IN THE SECOND SEMESTER OF FOURTH-YEAR HIGH SCHOOL MATHEMATICS COURSES
No full textThe second semester of the high school senior year has been associated with a lack of motivation among students and increased frustrations among parents and teachers. This qualitative study examines the achievement goals and engagement outcomes of second semester high school seniors in their mathematics classes. Data were collected from eight high school seniors, three of their parents, and two teachers enrolled at an all male college preparatory school in Pennsylvania. In-depth interviews were used to gather participants’ definitions of success prior to their senior year and during the second semester of their senior year. Student participants’ behavioral, emotional and cognitive engagements were assessed through directed interview questions and observations. Data were analyzed using a three goal framework of task-involvement, ego-involvement, and work-avoidance (Nicholls, Patashnick, & Nolen, 1985). The participants’ definitions of success suggested four themes. First, student participants defined success in mathematics consistently as they recalled their four years of high school and transition into the second semester of their senior year. Second, the phenomenon of senioritis was found to be more perceived than real for most of the participants. The work-avoidant participants described feeling the effects of senioritis for most of the second semester whereas the task-involved and ego-involved students reported brief effects before regaining focus. Third, students’ achievement goals in mathematics were found to be more closely aligned to their parents’ goals and less aligned to their teachers’ goals. Lastly, students described different achievement goals from one class to another during the same semester, at times even within the same discipline. Implications for practice and suggestions for future research were also discussed.Math & Science Educatio
The Slow-Coloring Game on Path Power Graphs
No full textThe Slow-Coloring Game is a game played on a graph G by two players which we will refer to as Lister and Painter. In the ith round, Lister marks a nonempty subset M of V (G) of uncolored vertices as eligible to receive color i, scoring |M| points. Painter then gives color i to a subset of M that is independent in G. The game ends when all of the vertices of G are colored. Note that at each stage the resulting coloring will be a proper coloring of V(G). Lister’s goal is to maximize the total score while Painter seeks to minimize the total score. The sum-color cost of a graph G, denoted s(G), is the best score each player can guarantee in the Slow-Coloring Game on G regardless of the play strategy of the other. Puleo and West gave upper and bounds for the sum-color cost for every tree T on n vertices. They also conjectured that this bound generalizes to k-trees. Mahoney, Puleo, and West provide the value for the sum-color cost of k-stars, we provide the value for the sum-color cost of k-paths
Model Predictive Control of Salinity and Water Level in a Hypothetical Polder Ditch: Is it Possible to Use the Discretized Linearized Physical Equations for Optimization
No full textSurface water salinization in deltaic areas due to saline groundwater exfiltration is an important issue. Fresh water diverted from the rivers is used for flushing the canals and the ditches in coastal areas to remove the low quality saline surface water mixed with saline groundwater. Worldwide, deltaic areas are under stress due to climate change, sea level increase and decrease in fresh water availability. The current fresh water management strategies in polders to overcome the salinization problem solely depends on uncontrolled freshwater use. However, this operation will not be effective during a scarce freshwater availability scenario and has to be revised for efficient management possibilities. With the advances in real time measurement of salinity and water level measurements, using a Model Predictive Control (MPC) scheme for the operation of a polder system is gaining popularity. MPC is a powerful control tool that can handle multiple objectives, consider the constraints and the uncertainties of the system. However, a MPC scheme requires a simple and reliable internal model that will be used to calculate the optimum control actions. The internal model should be robust, should reflect the system behaviour with enough detail and should not be computationally costly. In this paper, a MPC scheme is proposed using the discretized linearized De Saint Venant (SV) and Advection-Diffusion (AD) equations as the internal model of the controller. The proposed scheme will be able to control salinity and water level at any discretization point by manipulating the flushing and outflow discharges. This is an ongoing research with tests continuing on a realistic test case.Water Resource
Graph theory algorithms for real time control of a sewer network
No full textMany Dutch sewer networks are combined sewer systems, they carry both stormwater and foul water. They consist of multiple sub-networks, linked by pumps into a tree structure with the Waste Water Treatment Plant as its root. Within sub-networks sewage transport is by gravity driven flow. Usually the original design assumed local control. Later changes, additions and extensions sometimes reduced the effectiveness of the original design. In these cases central control can improve the performance of the system without costly new construction. We apply two algorithms from graph theory, one is based on stable flows in time, the other on quickest evacuation flows. Results on local control are included to provide a lower bound on performance. A linear programming problem based of a perfect forecast of the whole event provides an upper bound on performance.Water Resource
Seasonally Resolved Paleoclimate Reconstructions in Greenland Over the Past 14,000 Years Using Lake Sediments and Novel Oxygen Isotope Proxies
No full textSeasonally Resolved Paleoclimate Reconstructions in Greenland Over the Past 14,000 Years Using Lake Sediments and Novel Oxygen Isotope Proxies
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