2,510 research outputs found
Uncertainty Quantification of geochemical and mechanical compaction in layered sedimentary basins
In this work we propose an Uncertainty Quantification methodology for
sedimentary basins evolution under mechanical and geochemical compaction
processes, which we model as a coupled, time-dependent, non-linear,
monodimensional (depth-only) system of PDEs with uncertain parameters. While in
previous works (Formaggia et al. 2013, Porta et al., 2014) we assumed a
simplified depositional history with only one material, in this work we
consider multi-layered basins, in which each layer is characterized by a
different material, and hence by different properties. This setting requires
several improvements with respect to our earlier works, both concerning the
deterministic solver and the stochastic discretization. On the deterministic
side, we replace the previous fixed-point iterative solver with a more
efficient Newton solver at each step of the time-discretization. On the
stochastic side, the multi-layered structure gives rise to discontinuities in
the dependence of the state variables on the uncertain parameters, that need an
appropriate treatment for surrogate modeling techniques, such as sparse grids,
to be effective. We propose an innovative methodology to this end which relies
on a change of coordinate system to align the discontinuities of the target
function within the random parameter space. The reference coordinate system is
built upon exploiting physical features of the problem at hand. We employ the
locations of material interfaces, which display a smooth dependence on the
random parameters and are therefore amenable to sparse grid polynomial
approximations. We showcase the capabilities of our numerical methodologies
through two synthetic test cases. In particular, we show that our methodology
reproduces with high accuracy multi-modal probability density functions
displayed by target state variables (e.g., porosity).Comment: 25 pages, 30 figure
Erratum to: Textile Reinforced Concrete: experimental investigation on design parameters
Textile Reinforced Concrete (TRC) is an advanced cement-based material in which fabrics used as reinforcement can bring significant loads in tension, allowing architects and engineers to use thin cross-sections. Previous research projects, developed during the last 10 years mainly in Germany, Israel and the USA, have shown the capabilities of such a material. In this paper an extensive experimental investigation of TRC is presented: tensile tests were carried out to obtain a complete mechanical characterization of the composite material under standard conditions, considering the influence of different variables such as reinforcement ratio, fabric geometry, curing conditions, displacement rate and specimen size.
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Due to an unfortunate turn of events this article was published with wrong citations in the text to the references at the end of the article. In order to provide the correct information this article is hereafter published in its entirety with the correct citations and should be regarded as the final version by the reader
Identity in social context: Plurilingual families in Baden-Wuerttemberg and South Tyrol
In trying to understand how identity can be constructed in the face of diversity, plurilingual families are a focal point of interest, since they live between different cultures and identities. In our article, we assume along with Bucholtz and Hall (2005) that identity encompasses macro-level demographic categories, local ethnographically specific cultural positions as well as temporary, interactionally specific stances and participant roles. Based on this theoretical assumption, we will describe how plurilingual families construct their identity by comparing two different regions: the officially monolingual German federal state of Baden-Wuerttemberg and the officially trilingual Autonomous Province of Bolzano/South Tyrol. The analysis in this article is based on semi-structured interviews with and self-recordings of plurilingual families in Baden-Wuerttemberg and South Tyrol.Möchte man verstehen, wie Identität im Angesicht von Diversität konstruiert wird, sind mehrsprachige Familien von besonderem Interesse, leben sie doch an der Schnittstelle verschiedener Kulturen und Identitäten. Wir gehen mit Bucholtz und Hall (2005) davon aus, dass Identität demographische Kategorien auf der Makroebene genauso umfasst wie lokale, ethnographisch spezifische kulturelle Positionen und temporäre interaktionale Haltungen und Rollen. Ausgehend von dieser theoretischen Basis werden wir die Identitätskonstruktion mehrsprachiger Familien in zwei unterschiedlichen Regionen untersuchen: dem offiziell einsprachigen deutschen Bundesland Baden-Württemberg und der offiziell dreisprachigen Autonomen Provinz Bozen/Südtirol. Datengrundlage sind semi-strukturierte Interviews mit und Selbstaufnahmen von mehrsprachigen Familien in Baden-Württemberg und Südtirol
Silicon self-diffusion constants by tight-binding molecular dynamics
The thermodynamic integration method has been incorporated into the tight-binding molecular-dynamics scheme to compute formation free energies of native point defects in bulk silicon. By combining previous simulated diffusivity data with present free-energy estimates, we present a thorough quantum-mechanical picture of self-diffusion in silicon that is both consistent with the state-of-the-art experimental data and able to predict separately the vacancy and self-interstitial contributions.Peer reviewe
Amplifying the Effects of Contrast Agents on Magnetic Resonance Images Using a Deep Learning Method Trained on Synthetic Data
Doping incorporation paths in catalyst-free Be-doped GaAs nanowires
The incorporation paths of Be in GaAs nanowires grown by the Ga-assisted
method in molecular beam epitaxy has been investigated by electrical
measurements of nanowires with different doping profiles. We find that Be atoms
incorporate preferentially via the nanowire side facets, while the
incorporation path through the Ga droplet is negligible. We also demonstrate
that Be can diffuse into the volume of the nanowire giving an alternative
incorporation path. This work is an important step towards controlled doping of
nanowires and will serve as a help for designing future devices based on
nanowires.Comment: 4 pages, 4 figure
Wearable proximity sensors for monitoring a mass casualty incident exercise: a feasibility study
Over the past several decades, naturally occurring and man-made mass casualty
incidents (MCI) have increased in frequency and number, worldwide. To test the
impact of such event on medical resources, simulations can provide a safe,
controlled setting while replicating the chaotic environment typical of an
actual disaster. A standardised method to collect and analyse data from mass
casualty exercises is needed, in order to assess preparedness and performance
of the healthcare staff involved. We report on the use of wearable proximity
sensors to measure proximity events during a MCI simulation. We investigated
the interactions between medical staff and patients, to evaluate the time
dedicated by the medical staff with respect to the severity of the injury of
the victims depending on the roles. We estimated the presence of the patients
in the different spaces of the field hospital, in order to study the patients'
flow. Data were obtained and collected through the deployment of wearable
proximity sensors during a mass casualty incident functional exercise. The
scenario included two areas: the accident site and the Advanced Medical Post
(AMP), and the exercise lasted 3 hours. A total of 238 participants simulating
medical staff and victims were involved. Each participant wore a proximity
sensor and 30 fixed devices were placed in the field hospital. The contact
networks show a heterogeneous distribution of the cumulative time spent in
proximity by participants. We obtained contact matrices based on cumulative
time spent in proximity between victims and the rescuers. Our results showed
that the time spent in proximity by the healthcare teams with the victims is
related to the severity of the patient's injury. The analysis of patients' flow
showed that the presence of patients in the rooms of the hospital is consistent
with triage code and diagnosis, and no obvious bottlenecks were found
dose administration maneuvers and patient care in tobramycin dry powder inhalation therapy
Abstract The purpose of this work was to study a new dry powder inhaler (DPI) of tobramycin capable to simplify the dose administration maneuvers to maximize the cystic fibrosis (CF) patient care in antibiotic inhalation therapy. For the purpose, tobramycin/sodium stearate powder (TobraPS) having a high drug content, was produced by spray drying, characterized and the aerodynamic behavior was investigated in vitro using different RS01 DPI inhalers. The aerosols produced with 28, 56 or 112 mg of tobramycin in TobraPS powder using capsules size #3, #2 or #0 showed that there was quasi linear relationship between the amount loaded in the device and the FPD. An in vivo study in healthy human volunteers showed that 3–6 inhalation acts were requested by the volunteers to inhale 120 mg of TobraPS powder loaded in a size #0 capsule aerosolized with a prototype RS01 device, according to their capability to inhale. The amount of powder emitted at 4 kPa pressure drop at constant air flow well correlated with the in vivo emission at dynamic flow, when the same volume of air passed through the device. The novel approach for the administration of 112 mg of tobramycin in one capsule could improve the convenience and adherence of the CF patient to the antibiotic therapy
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