Search results for " Modelling"
showing 10 items of 1055 documents
Enhanced prediction of hemoglobin concentration in a very large cohort of hemodialysis patients by means of deep recurrent neural networks.
2019
Erythropoiesis Stimulating Agents (ESAs) have become a standard anemia management tool for End Stage Renal Disease (ESRD) patients. However, dose optimization constitutes an extremely challenging task due to huge inter and intra-patient variability in the responses to ESA administration. Current data-based approaches to anemia control focus on learning accurate hemoglobin prediction models, which can be later utilized for testing competing treatment choices and choosing the optimal one. These methods, despite being proven effective in practice, present several shortcomings which this paper intends to tackle. Namely, they are limited to a small cohort of patients and, even then, they fail to…
A Multivariate Age-Structured Stochastic Model with Immunization Strategies to Describe Bronchiolitis Dynamics
2021
Bronchiolitis has a high morbidity in children under 2 years old. Respiratory syncytial virus (RSV) is the most common pathogen causing the disease. At present, there is only a costly humanized monoclonal RSV-specific antibody to prevent RSV. However, different immunization strategies are being developed. Hence, evaluation and comparison of their impact is important for policymakers. The analysis of the disease with a Bayesian stochastic compartmental model provided an improved and more natural description of its dynamics. However, the consideration of different age groups is still needed, since disease transmission greatly varies with age. In this work, we propose a multivariate age-struct…
Predicting stiffness and strength of birch pulp:Polylactic acid composites
2016
This paper studies failure of birch pulp–polylactic acid composites. Stiffness and strength are calculated using the theory of short fibre composites and the results are compared to experimental data. The results differed from the experimental values by 0–6%. With less aligned fibres the short fibre theory is not feasible. The performance of the 40 wt% birch pulp – polylactic acid composite is predicted with X-ray microtomography based finite element modelling, and the results are compared with experiments. Stiffness results differed from experiments by 1–17% . By adding into the models a third material phase representing the interface between the fibres and the matrix, the stress–strain c…
Modelling biological nitrogen and phosphorus removal with soluble microbial products (SMP) production-degradation processes
2011
Over the last two decades, Membrane Bioreactors (MBR) are increasingly used for wastewater treatment. Mathematical modelling of MBR systems has played a key role in order to better explain the effect of their peculiarities. Indeed, several MBR models have been presented in literature in order to improve the knowledge on MBR systems: biological models, hybrid models which include soluble microbial product (SMP) modelling, physical models able to describe the membrane fouling and integrated models which couple the hybrid models with the physical ones. However, among the existing MBR models only few integrated models have been developed which take into account the existing relationship between…
Integrated Urban Water Modeling with Uncertainty Analysis
2005
In the last 20th years, the scientific world has got particular care towards the problems that involve the respect of the environment. According to this point, several researches were developed to describe the phenomena that take place during both wet and dry period and to increase the knowledge in this field. In particular, the attention was addressed towards the problems linked with the pollution of the water body because of the pollution carried by rainfall waters in the urban environment. In order to obtain a good description of the problem, it is important, of course, to analyze both quantity and quality aspects connected with all the transformation phases that characterize the urban w…
On the Finite Element Modeling of the Lumbar Spine: A Schematic Review
2023
Finite element modelling of the lumbar spine is a challenging problem. Lower back pain is among the most common pathologies in the global populations, owing to which the patient may need to undergo surgery. The latter may differ in nature and complexity because of spinal disease and patient contraindications (i.e., aging). Today, the understanding of spinal column biomechanics may lead to better comprehension of the disease progression as well as to the development of innovative therapeutic strategies. Better insight into the spine’s biomechanics would certainly guarantee an evolution of current device-based treatments. In this setting, the computational approach appears to be a remarkable …
Towards a reduction of greenhouse gas emission from wastewater treatment plants: a new plant wide experimental and modelling approach
2016
The increasing interest in greenhouse gas (GHG) emissions from wastewater treatment plants (WWTPs) has led to the development of new tools for their design and management. Studies about gas emissions show that the sewer collection and the wastewater treatment plant are anthropogenic GHG potential sources, so they contribute to the climate change and air pollution. A wastewater treatment plant receives wastewater from sewers and, while produces treated water for discharge into surface water, emits the three major greenhouse gases, CO2, CH4, and N2O, during the treatment processes, and additional amounts of CO2 and CH4 from the energy demands (Bani Shahabadi et al., 2009). Indeed, energy cons…
Application of computational fluid dynamics technique in electrodialysis/reverse electrodialysis processes
2022
This Chapter treats the application of CFD technique in ED/RED processes. CFD simulations are able to predict flow and mass transfer in channels filled with spacers or membrane profiles, by providing dimensionless correlations useful for process models. At a larger scale, manifolds of the stack and inlet/ outlet zones of the channel can be simulated. Numerical models can include the computation of the electrical potential, thus characterizing the process performance. Direct numerical simulations can elucidate the complex phenomenology of overlimiting transport and of chaotic electrokinetic flows.
Global sensitivity analysis in environmental water quality modelling: Where do we stand?
2014
Global sensitivity analysis (GSA) is a valuable tool to support the use of mathematical models for environmental systems. During the last years the water quality modelling field has embraced the use of GSA. Environmental water quality modellers have tried to transfer the knowledge and experience acquired in other disciplines. The main objective of this paper is to provide an informed problem statement of the issues surrounding GSA applications in the environmental water quality modelling field. Specifically, this paper aims at identifying, for each GSA method, the potential use, the critical issues to be solved and the limits identified in a comprehensive literature review. The paper shows …
Non-Linear Inductor Models Comparison for Switched-Mode Power Supplies Applications
2022
The use of non-linear power inductors, intended as devices exploited up to a current at which the inductance is halved, is of great interest in switched-mode power supplies (SMPSs). Indeed, it allows the use of lighter and cheaper inductors improving the power density. On the other hand, the analysis of SMPSs equipped with non-linear inductors requires appropriate modeling of the inductor reproducing the inductance versus current. This paper compares two main analytical models proposed in the literature: the former is based on a polynomial, and the latter exploits the arctangent function to reproduce the non-linearity of the inductance. Performance is compared by considering the effort of r…