Etude expérimentale et modélisation de la cinétique de combustion d'alcanes lourds, de kérosènes reformulés et de carburants modèles : formation de polluants

In recent years research activities on reformulated fuels for the aviation industry have increased. Indeed, the strong development of the airline industry pushes scientists to seek for alternative jet fuel intended for aerodynes in order to preserve oil but also to fight against global warming and air pollution. In this thesis we have conducted experiments on the oxidation of three heavy hydrocarbons, a conventional Jet A-1, reformulated jet fuels (bio-kerosene) and synthetic kerosene (Fischer-Tropsch jet fuel). These studies were carried out in jet stirred reactor at high pressure (10 atm), in a wide temperature range (550-1150 K), for three equivalence ratios (Ф=0.5, 1, and 2). Chemical analyses by Fourier Transformed Infra-Red spectrometry (FTIR) and gas chromatography (GC-FID-TCD-MS) allowed us to measure concentration profiles of reactants, stable intermediates and final products versus temperature. Detailed chemical kinetic reaction mechanisms adapted to the studied compounds were developed and validated by comparison with experimental results.Au cours de ces dernières années les activités de recherches sur les carburants reformulés destinés au secteur aéronautique ont considérablement augmenté. En effet, le fort développement du secteur aérien pousse les scientifiques à chercher une alternative au carburéacteur destiné aux aérodynes dans le but d’économiser le pétrole mais aussi de lutter contre le réchauffement climatique et la pollution atmosphérique. Dans cette thèse nous avons mené des expériences d’oxydation sur trois hydrocarbures lourds, un kérosène conventionnel Jet A-1, des kérosènes reformulés (bio kérosène) et de synthèse (carburant issu de la synthèse Fischer-Tropsch). Ces études ont été réalisées en réacteur auto-agité par jets gazeux à haute pression (10 atm), dans un large domaine de températures (550-1150 K) et à trois richesses (Ф=0,5, 1 et 2). Les analyses par spectrométrie d’absorption infrarouge à transformée de Fourier (IRTF) et la chromatographie en phase gazeuse (CPG-FID-TCD-MS) nous ont permis de mesurer les profils de concentration des réactifs, des produits finals et des intermédiaires stables en fonction de la température. Des mécanismes cinétiques détaillés adaptés aux composés étudiés ont été développés et validés par confrontation avec les résultats expérimentaux

Experimental and modeling study of combustion of high alkanes, reformulated kerosenes and surrogate fuels : pollutants formation

Au cours de ces dernières années les activités de recherches sur les carburants reformulés destinés au secteur aéronautique ont considérablement augmenté. En effet, le fort développement du secteur aérien pousse les scientifiques à chercher une alternative au carburéacteur destiné aux aérodynes dans le but d’économiser le pétrole mais aussi de lutter contre le réchauffement climatique et la pollution atmosphérique. Dans cette thèse nous avons mené des expériences d’oxydation sur trois hydrocarbures lourds, un kérosène conventionnel Jet A-1, des kérosènes reformulés (bio kérosène) et de synthèse (carburant issu de la synthèse Fischer-Tropsch). Ces études ont été réalisées en réacteur auto-agité par jets gazeux à haute pression (10 atm), dans un large domaine de températures (550-1150 K) et à trois richesses (Ф=0,5, 1 et 2). Les analyses par spectrométrie d’absorption infrarouge à transformée de Fourier (IRTF) et la chromatographie en phase gazeuse (CPG-FID-TCD-MS) nous ont permis de mesurer les profils de concentration des réactifs, des produits finals et des intermédiaires stables en fonction de la température. Des mécanismes cinétiques détaillés adaptés aux composés étudiés ont été développés et validés par confrontation avec les résultats expérimentaux.In recent years research activities on reformulated fuels for the aviation industry have increased. Indeed, the strong development of the airline industry pushes scientists to seek for alternative jet fuel intended for aerodynes in order to preserve oil but also to fight against global warming and air pollution. In this thesis we have conducted experiments on the oxidation of three heavy hydrocarbons, a conventional Jet A-1, reformulated jet fuels (bio-kerosene) and synthetic kerosene (Fischer-Tropsch jet fuel). These studies were carried out in jet stirred reactor at high pressure (10 atm), in a wide temperature range (550-1150 K), for three equivalence ratios (Ф=0.5, 1, and 2). Chemical analyses by Fourier Transformed Infra-Red spectrometry (FTIR) and gas chromatography (GC-FID-TCD-MS) allowed us to measure concentration profiles of reactants, stable intermediates and final products versus temperature. Detailed chemical kinetic reaction mechanisms adapted to the studied compounds were developed and validated by comparison with experimental results

Etude expérimentale et modélisation de la cinétique de combustion d'alcanes lourds, de kérosènes reformulés et de carburants modèles : formation de polluants

In recent years research activities on reformulated fuels for the aviation industry have increased. Indeed, the strong development of the airline industry pushes scientists to seek for alternative jet fuel intended for aerodynes in order to preserve oil but also to fight against global warming and air pollution. In this thesis we have conducted experiments on the oxidation of three heavy hydrocarbons, a conventional Jet A-1, reformulated jet fuels (bio-kerosene) and synthetic kerosene (Fischer-Tropsch jet fuel). These studies were carried out in jet stirred reactor at high pressure (10 atm), in a wide temperature range (550-1150 K), for three equivalence ratios (Ф=0.5, 1, and 2). Chemical analyses by Fourier Transformed Infra-Red spectrometry (FTIR) and gas chromatography (GC-FID-TCD-MS) allowed us to measure concentration profiles of reactants, stable intermediates and final products versus temperature. Detailed chemical kinetic reaction mechanisms adapted to the studied compounds were developed and validated by comparison with experimental results.Au cours de ces dernières années les activités de recherches sur les carburants reformulés destinés au secteur aéronautique ont considérablement augmenté. En effet, le fort développement du secteur aérien pousse les scientifiques à chercher une alternative au carburéacteur destiné aux aérodynes dans le but d’économiser le pétrole mais aussi de lutter contre le réchauffement climatique et la pollution atmosphérique. Dans cette thèse nous avons mené des expériences d’oxydation sur trois hydrocarbures lourds, un kérosène conventionnel Jet A-1, des kérosènes reformulés (bio kérosène) et de synthèse (carburant issu de la synthèse Fischer-Tropsch). Ces études ont été réalisées en réacteur auto-agité par jets gazeux à haute pression (10 atm), dans un large domaine de températures (550-1150 K) et à trois richesses (Ф=0,5, 1 et 2). Les analyses par spectrométrie d’absorption infrarouge à transformée de Fourier (IRTF) et la chromatographie en phase gazeuse (CPG-FID-TCD-MS) nous ont permis de mesurer les profils de concentration des réactifs, des produits finals et des intermédiaires stables en fonction de la température. Des mécanismes cinétiques détaillés adaptés aux composés étudiés ont été développés et validés par confrontation avec les résultats expérimentaux

Kinetics of Oxidation of a Reformulated Jet Fuel (1-Hexanol/Jet A-1) in a Jet-Stirred Reactor: Experimental and Modeling Study

International audienc

Experimental Study of the Oxidation of N -Tetradecane in a Jet-Stirred Reactor (JSR) and Detailed Chemical Kinetic Modeling

International audienc

Assessment of the Performance of Lactate Dehydrogenase-Based Rapid Diagnostic Test for Malaria in Djibouti in 2022–2023

International audienceUntil 2020, Djiboutian health authorities relied on histidine-rich protein-2 (HRP2)-based rapid diagnostic tests (RDTs) to establish the diagnosis of Plasmodium falciparum. The rapid spread of P. falciparum histidine-rich protein-2 and -3 (pfhrp2/3) gene-deleted parasite strains in Djibouti has led the authorities to switch from HRP2-based RDTs to lactate dehydrogenase (LDH)-based RDTs targeting the plasmodial lactate dehydrogenase (pLDH) specific for P. falciparum and P. vivax (RapiGEN BIOCREDIT Malaria Ag Pf/Pv pLDH/pLDH) in 2021. This study was conducted with the primary objective of evaluating the diagnostic performance of this alternative RDT. Operational constraints related, in particular, to the implementation of this RDT during the COVID-19 pandemic were also considered. The performance of BIOCREDIT Malaria Ag Pf/Pv (pLDH/pLDH) RDT was also compared to our previously published data on the performance of two HRP2-based RDTs deployed in Djibouti in 2018–2020. The diagnosis of 350 febrile patients with suspected malaria in Djibouti city was established using two batches of RapiGEN BIOCREDIT Malaria Ag Pf/Pv (pLDH/pLDH) RDT over a two-year period (2022 and 2023) and confirmed by real-time quantitative polymerase chain reaction. The sensitivity and specificity for the detection of P. falciparum were 88.2% and 100%, respectively. For P. vivax, the sensitivity was 86.7% and the specificity was 100%. Re-training and closer supervision of the technicians between 2022 and 2023 have led to an increased sensitivity to detect P. falciparum (69.8% in 2022 versus 88.2% in 2023; p < 0.01). The receiver operating characteristic curve analysis highlighted a better performance in the diagnosis of P. falciparum with pLDH-based RDTs compared with previous HRP2-based RDTs. In Djibouti, where pfhrp2-deleted strains are rapidly gaining ground, LDH-based RDTs seem to be more suitable for diagnosing P. falciparum than HRP2-based RDTs. Awareness-raising and training for technical staff have also been beneficial

Molecular investigation of malaria-infected patients in Djibouti city (2018–2021)

Abstract Background The Republic of Djibouti is a malaria endemic country that was in pre-elimination phase in 2006–2012. From 2013, however, malaria has re-emerged in the country, and its prevalence has been increasing every year. Given the co-circulation of several infectious agents in the country, the assessment of malaria infection based on microscopy or histidine-rich protein 2 (HRP2)-based rapid diagnostic tests (RDT) has shown its limitations. This study, therefore, aimed to assess the prevalence of malaria among febrile patients in Djibouti city using more robust molecular tools. Methods All suspected malaria cases reported to be microscopy-positive were randomly sampled (n = 1113) and included in four health structures in Djibouti city over a 4-year period (2018–2021), mainly during the malaria transmission season (January–May). Socio-demographic information was collected, and RDT was performed in most of the included patients. The diagnosis was confirmed by species-specific nested polymerase chain reaction (PCR). Data were analysed using Fisher’s exact test and kappa statistics. Results In total, 1113 patients with suspected malaria and available blood samples were included. PCR confirmed that 788/1113 (70.8%) were positive for malaria. Among PCR-positive samples, 656 (83.2%) were due to Plasmodium falciparum, 88 (11.2%) Plasmodium vivax, and 44 (5.6%) P. falciparum/P. vivax mixed infections. In 2020, P. falciparum infections were confirmed by PCR in 50% (144/288) of negative RDTs. After the change of RDT in 2021, this percentage decreased to 17%. False negative RDT results were found more frequently (P < 0.05) in four districts of Djibouti city (Balbala, Quartier 7, Quartier 6, and Arhiba). Malaria occurred less frequently in regular bed net users than in non-users (odds ratio [OR]: 0.62, 95% confidence interval [CI]: 0.42–0.92). Conclusions The present study confirmed the high prevalence of falciparum malaria and, to a lesser extent, vivax malaria. Nevertheless, 29% of suspected malaria cases were misdiagnosed by microscopy and/or RDT. There is a need to strengthen the capacity for diagnosis by microscopy and to evaluate the possible role of P. falciparum hrp2 gene deletion, which leads to false negative cases of P. falciparum

Correction: Molecular investigation of malaria-infected patients in Djibouti city (2018–2021)

International audienc