Search results for " modelling"
showing 10 items of 1055 documents
A mathematical approach to predict the solids concentration in anaerobic membrane bioreactos (AnMBR): Evaluation of the volatile solids solubilization
2020
[EN] Anaerobic Membrane Bioreactors (AnMBR) are gaining attention as a suitable approach for sustainable low-strength wastewater treatment, as they bring together the advantages of both anaerobic treatments and membrane bioreactors. However, increasing the sludge retention time (SRT) necessary to favor hydrolysis increases the suspended solids concentration potentially leading to decreased permeate flux. Therefore, the availability of a mathematical approach to predict the solids concentration within an AnMBR can be very useful. In this work, a mathematical model describing the volatile solids concentration within the reactor as a function of the operating parameters and the influent charac…
PMT: New analytical framework for automated evaluation of geo-environmental modelling approaches
2019
Geospatial computation, data transformation to a relevant statistical software, and step-wise quantitative performance assessment can be cumbersome, especially when considering that the entire modelling procedure is repeatedly interrupted by several input/output steps, and the self-consistency and self-adaptive response to the modelled data and the features therein are lost while handling the data from different kinds of working environments. To date, an automated and a comprehensive validation system, which includes both the cutoff-dependent and –independent evaluation criteria for spatial modelling approaches, has not yet been developed for GIS based methodologies. This study, for the fir…
Determinants of performance drivers in online food delivery platforms: a dynamic performance management perspective
2022
PurposeThis study aims to demonstrate that the Dynamic Performance Management (DPM) framework, integrating performance management with system dynamics modelling, enables decision-makers to identify sustainable strategies in online food delivery platforms, thereby avoiding company failure.Design/methodology/approachThis study undertakes a multistep methodological approach. After the literature review, a retrospective case study approach was used. To build the DPM framework and the system dynamics simulation model, primary and secondary data were collected and analysed.FindingsThis study by adopting the DPM perspective highlights the critical role performance drivers play to assess the viabil…
Late frost damage risk for viticulture under future climate conditions: a case study for the Luxembourgish winegrowing region
2013
Background and Aims Late frosts are a significant risk to grape production in frost-prone viticultural regions. Increasing air temperature because of climate change is likely to advance grape budburst and last frost events in spring. So far, it is unclear whether one trend will be more pronounced than the other, and hence, whether the risk of late frost damage will increase or decrease. The aim of this work was to investigate the future frost risk in the Luxembourgish winegrowing region by assessing the effect of simulated future climate conditions on the timing of budburst and last frost date. Methods and Results Late frost risk was assessed by combining: (i) a phenological model for budbu…
Visión de los maestros en formación sobre los modelos científicos y sus funciones en las ciencias y en su enseñanza
2017
Este estudio examina la visión de 201 futuros maestros sobre los modelos científicos y sus funciones en ciencias y en su enseñanza. Se diseñó e implementó un cuestionario con cinco preguntas abiertas, de las cuales se analizan dos ¿Qué se entiende por modelo científico? y ¿Para qué consideras que son utilizados los modelos en ciencias? ¿Y en la enseñanza de las ciencias? Los resultados mostraron que, aunque un 24,5% reconocen que un modelo científico es una representación simplificada de un fenómeno, encontramos que un 22,8% lo consideran como “método” de trabajo de los científicos En cuanto a sus funciones, un 45,7% identifican los modelos como recursos para explicar, resumir o ejemplifica…
A study of the material in the ATLAS inner detector using secondary hadronic interactions
2011
The ATLAS inner detector is used to reconstruct secondary vertices due to hadronic interactions of primary collision products, so probing the location and amount of material in the inner region of ATLAS. Data collected in 7 TeV pp collisions at the LHC, with a minimum bias trigger, are used for comparisons with simulated events. The reconstructed secondary vertices have spatial resolutions ranging from ~ 200μm to 1 mm. The overall material description in the simulation is validated to within an experimental uncertainty of about 7%. This will lead to a better understanding of the reconstruction of various objects such as tracks, leptons, jets, and missing transverse momentum.
Study of the material of the ATLAS inner detector for Run 2 of the LHC
2017
The ATLAS inner detector comprises three different sub-detectors: the pixel detector, the silicon strip tracker, and the transition-radiation drift-tube tracker. The Insertable B-Layer, a new innermost pixel layer, was installed during the shutdown period in 2014, together with modifications to the layout of the cables and support structures of the existing pixel detector. The material in the inner detector is studied with several methods, using a low-luminosity root s = 13 TeV pp collision sample corresponding to around 2.0 nb(-1) collected in 2015 with the ATLAS experiment at the LHC. In this paper, the material within the innermost barrel region is studied using reconstructed hadronic in…
From local measures to regional impacts: Modelling changes in nutrient loads to the Baltic Sea
2021
Study Region: Our study region is the Baltic Sea Drainage Basin (BSDB), which covers an area of 1.8 Mio km2 distributed over 14 countries in northern Europe. Study Focus: We use a large-scale hydrological and nutrient transport model (E-HYPE) to model basin-wide impacts of measure scenarios on the Baltic Sea, where eutrophication is a critical issue for the marine ecosystem. We constructed measure scenarios based on stakeholder acceptance, established in workshops in different regions around the Baltic. These measures include local stream reach to catchment scale measures aiming to reduce nutrient transport into the stream network (buffer strips, stormwater ponds) and measures aiming to red…
Stochastic seismic analysis of hydrodynamic pressure in dam reservoir systems
2002
Hydrodynamic seismic-induced pressure requires careful consideration in the aseismic design of dams. Effects induced by earthquake excitation may cause many-fold increments of hydrostatic pressure. In this study earthquake excitation has been modelled by means of random process theory obtaining the response statistics of a dam-reservoir dynamical system. The analysis has been conducted assuming a rigid retaining wall of the reservoir and dissipative fluid. Copyright © 2002 John Wiley & Sons, Ltd.
A layer correlation technique for pion energy calibration at the 2004 ATLAS Combined Beam Test
2010
A new method for calibrating the hadron response of a segmented calorimeter is developed and successfully applied to beam test data. It is based on a principal component analysis of energy deposits in the calorimeter layers, exploiting longitudinal shower development information to improve the measured energy resolution. Corrections for invisible hadronic energy and energy lost in dead material in front of and between the calorimeters of the ATLAS experiment were calculated with simulated Geant4 Monte Carlo events and used to reconstruct the energy of pions impinging on the calorimeters during the 2004 Barrel Combined Beam Test at the CERN H8 area. For pion beams with energies between 20GeV…