Macroscopic corrosion front computations of sulfate attack in sewer pipes based on a micro-macro reaction-diffusion model

We consider a two-scale reaction diffusion system able to capture the corrosion of concrete with sulfates. Our aim here is to define and compute two macroscopic corrosion indicators: typical pH drop and gypsum profiles. Mathematically, the system is coupled, endowed with micro-macro transmission conditions, and posed on two different spatially-separated scales: one microscopic (pore scale) and one macroscopic (sewer pipe scale). We use a logarithmic expression to compute values of pH from the volume averaged concentration of sulfuric acid which is obtained by resolving numerically the two-scale system (microscopic equations with direct feedback with the macroscopic diffusion of one of the reactants). Furthermore, we also evaluate the content of the main sulfatation reaction (corrosion) product –the gypsum– and point out numerically a persistent kink in gypsum's concentration profile. Finally, we illustrate numerically the position of the free boundary separating corroded from not-yet-corroded regions

The design of a clicker game for text labelling

Games for text annotation / labelling are becoming more common, but it's difficult to find a mechanics that fits. In this work we discuss a clicker game that can support text annotation. We believe this type of game is uniquely suited to addressing some of the challenges faced by games featuring text annotation as a core task

Experiment-driven development of a GWAP for marking segments in text

Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee© 2017 Copyright is held by the owner/author(s). This paper describes TileAttack, an innovative highly configurable game-with-a-purpose (GWAP) designed to gather annotations for text segmentation tasks whilst exploring the effects of different game mechanics on GWAP for NLP (Natural Language Processing) problems, with a view to improving both quality of player contributions and player uptake. In this work we present a pilot experiment that shows TileAttack labelling "mentions" and being used to test the effects of in game time constraints on accuracy and player engagement. We present the results of this experiment using a set of metrics derived from those used for evaluating Free-To-Play (F2P) games

Meteor Trail Advection Observed During the 1998 Leonid Shower

Sodium resonance lidar observations of meteor trails are reported from the 1998 Leonid shower experimental at the Starfire Optical Range Kirtland Air Force Base, NM (35.0º N, 106.5º W ). The lidar was operating in a spatially scanning mode that allowed tracking for up to one half-hour. Three trails are presented here whose motion allowed inference of radial as well as vector wind components and apparent diffusivities. The winds are derived independently using the narrow linewidth sodium (Na) resonance Doppler lidar technique and are compared with the tracking results

First Observations of Long-Lived Meteor Trains with Resonance Lidar and Other Optical Instruments

In November 1998 the earth passed through a maximum in the cometary material responsible for the yearly Leonids meteor shower. The meteor storm event produced numerous examples of long-lived chemiluminescent trails--visible to the naked eye over New Mexico, where a major observation campaign was centered. One trail was detected for over an hour with a CCD camera employing a narrow sodium filter, and many others were observed for over ten minutes each. For the first time, sodium densities in such trails were measured while also being imaged in sodium light. We have verified one source of long-lived light emissions--a sodium-catalyzed reaction involving ozone--but it is far too weak to explain the visibility of such trails. In addition, we present a new explanation for the cylindrical shell appearance long reported for chemiluminescent trails and show that ozone depletion by chemical processes is a possible explanation for this phenomenon

Observations of persistent Leonid meteor trails 3. The ‘‘Glowworm’’

A spectacular, well-observed Leonid meteor of visual magnitude -14.3 appeared on 17 November 1998 and left a lingering trail, dubbed the Glowworm, that was well studied. From a location on Kirtland Air Force Base, near Albuquerque, New Mexico, we obtained CCD images of the trail from 94 to 203 s after the meteor and recorded a video with an intensified camera for even longer. From information obtained with a sodium lidar half an hour after the meteor, we have determined that a gravity wave with a vertical wavelength of 2.4 km was responsible for the right-angled appearance of the trail. The trail ended abruptly at 85 km, and its uppermost altitude may have been no greater than 91 km. We designate the Glowworm a Type I trail: one that is wide (1 km), cloudy in appearance, has high diffusion rates (800m2 s-1), high total line emission rates (1.5 x 1018 photons m-1 s-1), and is optically thicker than Type II trails. The lower parts of the Diamond Ring, another Leonid lingering trail that appeared 38 min earlier than the Glowworm, define the Type II trails, which appear as narrow, optically thinner parallel trails, with low diffusion rates (12 m2 s-1) and total line emission rates (1–3 x 1016 photons m1 s-1). No explanation is offered for the two orders of magnitude difference in these quantities. The Glowworm meteor produced infrasound [ReVelle and Whitaker, 1999], from which a meteoroid mass estimate of 522 g was made. We compare our photometry to a detailed numerical modeling of the shape of the trail and emission from the Glowworm made by Zinn et al. [1999], who find that the largest contributors to emission recorded by our CCD and video cameras are atmospheric O2 vibrational bands. Compared to our measurements, their calculated emission is too high by two orders of magnitude, but since most of O2 emission may be absorbed by atmospheric O2 before it reaches the ground, this may indeed be the primary contributor to the observed flux. Although the calculations of Zinn et al. lead to a hollow cylinder appearance which may be appropriate for the Glowworm, it is not pronounced enough to account for the complete darkness between the parallel structures seen in Type II trails. An upper limit to backscattering from dust of 3.7 x 10-5 of the expected return was found from directing a 180 W copper vapor laser at the Glowworm

Testing game mechanics in games with a purpose for NLP applications

This paper describes a highly configurable game-with-a-purpose (GWAP) designed to explore the effects of different game mechanics on GWAP for NLP problems with a view to improving both quality of annotation and player uptake. The details of the game are discussed along with some of the questions the game hopes to answer

Information search in a professional context – exploring a collection of professional search tasks

Effective Protection of Fundamental Rights in a pluralist worl

Observations of Persistent Leonid Meteor Trails 2. Photometry and Numerical Modeling

During the 1998 Leonid meteor shower, multi-instrument observations of persistent meteor trains were made from the Starfire Optical Range on Kirtland Air Force Base, New Mexico, and from a secondary site in nearby Placitas, New Mexico. The University of Illinois Na resonance lidar measured the Na density and temperature in the trains, while various cameras captured images and videos of the trains, some of which were observed to persist for more than 30 min. The Na density measurements allow the contribution of Na airglow to the observed train luminescence to be quantified for the first time. To do this, persistent train luminescence is numerically modeled. Cylindrical symmetry is assumed and observed values of the Na density, temperature, and diffusivity are used. It is found that the expected Na luminosity is consistent with narrow band CCD all-sky camera observations, but that these emissions can contribute only a small fraction of the total light observed in a 0.5-1 µbandwidth. Other potential luminosity sources are examined in particular light resulting from the possible excitation of monoxide of meteoric metals (particular FeO) and O2(b¹ ) during reactions between atmospheric oxygen species and meteoric metals. If is found that the total luminosity of these combined processes falls somewhat short of explaining the observed brightness, and thus additional luminosity sources still are needed. In addition, the brightness distribution, the so-called hollow cylinder effect, remains unexplained