The proton exchange membrane fuel cell systems (PEMFC)s are interesting devices for energy conversion. Recent researches are aimed at developing new monitoring and diagnosis techniques; a good ...management of these systems would allow optimizing the performance and reducing their degradation. The objective of a suitable diagnostic tool is to identify and isolate the different faults that may occur in the system being monitored in real time. Therefore, the main features of computational methods are accuracy, reliability and high computational speed. In order to perform the diagnosis, it is necessary to evaluate different approaches. In this work different model-based approaches are investigated as well as their validation and applications. An overview of different methodologies available in the literature is proposed, which is oriented to help in developing suitable diagnostic tool for PEMFC monitoring and fault detection and isolation (FDI).
•Model-based methodologies for PEMFC diagnosis are summarized based on 59 articles.•The main approaches are introduced and discussed separately.•Parameter identification, observer-based and parity space methods are presented.•Models are classified in white-, grey- and black-box categories.•Application areas, advantages and limitations are underlined for each approach.
A review of non-model based methodologies applied to diagnosis of Proton Exchange Membrane Fuel Cell (PEMFC) system is presented. Three types of non-model based methods including artificial ...intelligence, statistical method and signal processing method are discussed and compared. The artificial intelligence one, divided into Neural Network (NN), Fuzzy Logic (FL) and neural-fuzzy method, is applied as a fault classifier which is quite different from its role in model-based method. Linear feature reduction methods including Principle Component Analysis (PCA) and Fisher Discriminant Analysis (FDA), and nonlinear ones such as Kernel PCA (KPCA) and Kernel FDA (KFDA) are demonstrated as part of statistical methods. Additionally, a statistical theory based classifier- Bayesian Network (BN) is also introduced in this part. As for signal processing method, both Fast Fourier Transform (FFT) for stationary signals and short-time Fourier Transform (STFT), as well as Wavelet Transform (WT) for non-stationary signals are introduced. Since each method has its advantages and limitations, a comparison is made finally and hybrid approaches resulting from integration of different methods are believed to be promising.
•Non-model based methodologies applied to diagnosis of PEMFC system are summarized.•AI method, statistical method and signal processing one are discussed.•Hybrid approaches resulting from the above methods are believed to be promising.•A general structure of the hybrid approach composed of four steps is given.
Spinal muscular atrophy is a rare, autosomal recessive, neuromuscular disease caused by biallelic loss of the survival motor neuron 1 (SMN1) gene, resulting in motor neuron dysfunction. In this ...STR1VE-EU study, we aimed to evaluate the safety and efficacy of onasemnogene abeparvovec gene replacement therapy in infants with spinal muscular atrophy type 1, using broader eligibility criteria than those used in STR1VE-US.
STR1VE-EU was a multicentre, single-arm, single-dose, open-label phase 3 trial done at nine sites (hospitals and universities) in Italy (n=4), the UK (n=2), Belgium (n=2), and France (n=1). We enrolled patients younger than 6 months (180 days) with spinal muscular atrophy type 1 and the common biallelic pathogenic SMN1 exon 7–8 deletion or point mutations, and one or two copies of SMN2. Patients received a one-time intravenous infusion of onasemnogene abeparvovec (1·1 × 1014 vector genomes vg/kg). The outpatient follow-up consisted of assessments once per week starting at day 7 post-infusion for 4 weeks and then once per month until the end of the study (at age 18 months or early termination). The primary outcome was independent sitting for at least 10 s, as defined by the WHO Multicentre Growth Reference Study, at any visit up to the 18 months of age study visit, measured in the intention-to-treat population. Efficacy was compared with the Pediatric Neuromuscular Clinical Research (PNCR) natural history cohort. This trial is registered with ClinicalTrials.gov, NCT03461289 (completed).
From Aug 16, 2018, to Sept 11, 2020, 41 patients with spinal muscular atrophy were assessed for eligibility. The median age at onasemnogene abeparvovec dosing was 4·1 months (IQR 3·0–5·2). 32 (97%) of 33 patients completed the study and were included in the ITT population (one patient was excluded despite completing the study because of dosing at 181 days). 14 (44%, 97·5% CI 26–100) of 32 patients achieved the primary endpoint of functional independent sitting for at least 10 s at any visit up to the 18 months of age study visit (vs 0 of 23 untreated patients in the PNCR cohort; p<0·0001). 31 (97%, 95% CI 91–100) of 32 patients in the ITT population survived free from permanent ventilatory support at 14 months compared with six (26%, 8–44) of 23 patients in the PNCR natural history cohort (p<0·0001). 32 (97%) of 33 patients had at least one adverse event and six (18%) had adverse events that were considered serious and related to onasemnogene abeparvovec. The most common adverse events were pyrexia (22 67% of 33), upper respiratory infection (11 33%), and increased alanine aminotransferase (nine 27%). One death, unrelated to the study drug, occurred from hypoxic-ischaemic brain damage because of a respiratory tract infection during the study.
STR1VE-EU showed efficacy of onasemnogene abeparvovec in infants with symptomatic spinal muscular atrophy type 1. No new safety signals were identified, but further studies are needed to show long-term safety. The benefit–risk profile of onasemnogene abeparvovec seems favourable for this patient population, including those with severe disease at baseline.
Novartis Gene Therapies.
A Review on solid oxide fuel cell models Wang, K.; Hissel, D.; Péra, M.C. ...
International journal of hydrogen energy,
06/2011, Letnik:
36, Številka:
12
Journal Article
Recenzirano
Since the model plays an important role in diagnosing solid oxide fuel cell (SOFC) system, this paper proposes a review of existing SOFC models for model-based diagnosis of SOFC stack and system. ...Three categories of modelling based on the white-, the black- and the grey-box approaches are introduced. The white-box model includes two types, i.e. physical model and equivalent circuit model based on EIS technique. The black-box model is based on artificial intelligence and its realisation relies mainly on experimental data. The grey-box model is more flexible: it is a physical representation but with some parts being modelled empirically. Validation of models is discussed and a hierarchical modelling approach involving all of three modelling methods is briefly mentioned, which gives an overview of the design for implementing a generic diagnostic tool on SOFC system.
In this paper, a graphical model of Proton Exchange Membrane (PEM) electrolyser is presented. The modelling is performed with respect to a generic approach then it is tuned regarding the electrolyser ...considered for the experimental validation.
The graphical modelling based on Energetic Macroscopic Representation (EMR) has advantages such as readability, modularity, structural and functional characteristics. The EMR modelling presented here allows the modelling of multi-physics components and highlights the interactions of the electrochemical, thermodynamical, thermal and fluidic phenomena that occur simultaneously in an electrolyser.
Generally, in electrolyser models, the temperature is considered as a parameter with different constant values and its influence on other variables of the model is observed. In this paper, the dynamic evolution of the temperature in the stack and the supply water tank is described. The static behaviour of the electrical variables is also studied. To validate the model, a small-scale laboratory electrolyser is used as an experimental tool. The electrical parameters are identified using Matlab/Simulink curves fitting tools. Then, the whole model is simulated. The simulation results fit very well the experimental data.
Furthermore, the parameters values of this model are compared to those of the literature and their relevance is pointed out. Using Energetic Macroscopic Representation, the proposed model describes accurately the experimental electrolyser; moreover it can be easily adapted to other electrolysers.
Research activities concerning proton exchange membrane fuel cells (PEMFC) are mainly aimed to reach lifespan objective. To this purpose numerous experimental tests are usually scheduled. In this ...framework, the studies involved in system aging and lifetime prediction can be extremely time consuming and costly. Thus, introducing accelerated aging methodologies to reduce test duration and costs becomes now an open question at an international level. This article aims to raise awareness on this topic, analysing the accelerated stress test (AST) applications proposed in PEMFC domain. An overview on the main protocols reported in literature is then presented focusing on PEMFC lifetime prediction applications. The open issues related to the protocols’ development and to the AST coupling with natural aging are also evaluated. Finally, new proposals are presented. In the last part of the article the fundamentals to develop a new approach for lifetime prediction based on adaptable load cycling are introduced.
•An overview on accelerated stress test (AST) protocol applications is presented.•The main open points for PEMFC lifetime prediction application are highlighted.•A proposal for a new AST protocol based on adaptable load cycling is presented.•The protocol is built to stress the effects induced by general dynamic loads.•Both protocol and metrics are designed to develop a lifetime prediction model.
This paper presents a Proton Exchange Membrane Fuel Cell model suitable for water management analysis. In order to be integrated into a complete fuel cell vehicle simulation for real-time control and ...energy management designs, Energetic Macroscopic Representation is used. An experimental validation is performed and electric and gaseous behaviors are studied in particular. The integration of the developed model into a vehicle simulation, in which the FC is used as a range extender, demonstrates the use of the model and allows the study of the behavior of this system.
► This paper presents a Proton Exchange Membrane Fuel Cell model suitable for water management analysis. ► An experimental validation of the model is proposed. ► The objectives of the model are: integration into a system simulation, local & control design. ► As an example, the model is integrated into a complete vehicle simulation.
A voltage decrease in the long‐term operation of hydrogen fuel cell (FC) electric cars under steady settings under constant load and dynamic operating conditions is a performance constraint of ...concern. Although accelerated stress test (AST) procedures have been sought to diagnose degradation, the AST results of FC stacks have not been reported extensively. The purpose of this article is to discuss the generation of AST of FC stacks based on real load profiles and the consequences of load changes and start‐stop circumstances, which are mostly generated by common driven cycles in urban regions with high driving speeds and traffic jams. The highlight of this study is to analyze the effects of cycle repetition on the aging FC stack, especially the voltage degradation factor, degradation kinetics, and energy consumption. The relation between actual system temperatures in side cells assembled in the FC stacks and material degradation was also analyzed. The results presented high heat accumulation, related to chemical degradation, that occurred during load cycling and may result in membrane thinning and pinholes in the membrane. Temperature cycling corresponded to mechanical degradation generated during the start‐stop cycling test, which may lead to membrane degradations—cracking, tearing, and pinholes.
To manage an electrical network in a stationary application or in an embedded application such as hybrid or electrical vehicles, it is necessary to understand and to model the electrical behaviour of ...the sources on board. This paper deals with the characterization of supercapacitors as electrical power sources, in order to model them. Three equivalent electrical circuit models of supercapacitor are proposed, corresponding to different levels of modelling. The identification of these model parameters is carried out with adapted characterization tests, such as charge and discharge test at constant current and Electrochemical Impedance Spectroscopy in environmental constraints. The experimental results are compared and analysed, for many characterizations in different test conditions in terms of voltage (from 0.5 to 2.7 V), temperature (from -20 to 55 degree C), frequency (from 50 mHz to 20 kHz) and on many supercapacitor cells of several capacitances (650 F, 1200 F and 3000 F) and from two suppliers (Maxwell and Batscap).
