Gas sensor array applied to the monitoring of biogas process

There is a lack of simple online monitoring system to control the performances of biogas reactors. The electronic nose technology appears to be an adapted device to deliver fast information about process disturbances in anaerobic reactors as it is adequate for online monitoring. In this study, twelve anaerobic mini-reactors were supervised with a home-made e-nose to observe process reaction in relation to organic overloads events. Usually, to avoid overload situations, on farms reactors are not fed at maximum load capacity, resulting in non optimized biogas production. The objective of the experiment was to determine if the gas sensors array feature can be related to the process state and if an indirect state variable, giving early warning of process faults, can be derived from the e-nose response. The results demonstrated that focusing on gas phase of anaerobic reactors with a simple device composed of an array of non-specific gas sensors helped in the warning of disorders of the anaerobic digestion process. Mahalanobis distance from a cautious feeding group (group of observations indicating a good process) can be used as an indirect variable to evaluate the intensity of the state disorder. Euclidean distance has been also calculated but it was less informative than the Mahalanobis distance.Optibioga

Two warm Neptunes transiting HIP 9618 revealed by TESS and Cheops

peer reviewedHIP 9618 (HD 12572, TOI-1471, TIC 306263608) is a bright (G = 9.0 mag) solar analogue. TESS photometry revealed the star to have two candidate planets with radii of 3.9 ± 0.044 R (HIP 9618 b) and 3.343 ± 0.039 R (HIP 9618 c). While the 20.77291 d period of HIP 9618 b was measured unambiguously, HIP 9618 c showed only two transits separated by a 680-d gap in the time series, leaving many possibilities for the period. To solve this issue, CHEOPS performed targeted photometry of period aliases to attempt to recover the true period of planet c, and successfully determined the true period to be 52.56349 d. High-resolution spectroscopy with HARPS-N, SOPHIE, and CAFE revealed a mass of 10.0 ± 3.1M for HIP 9618 b, which, according to our interior structure models, corresponds to a 6.8 ± 1.4 per cent gas fraction. HIP 9618 c appears to have a lower mass than HIP 9618 b, with a 3-sigma upper limit of 50 d, opening the door for the atmospheric characterization of warm (Teq < 750 K) sub-Neptunes

Unusual traits of the pyoverdin-mediated iron acquisition system in Pseudomonas putida strain BTP1.

Fluorescent Pseudomonas species are characterized by the production of pyoverdin-type siderophores for Fe3+ acquisition in iron-limited environments. Since it produces a structurally specific pyoverdin, Pseudomonas putida strain BTP1 could represent a valuable tool in an attempt to correlate the structural features of these compounds with some specificity in their two main properties i.e. affinity for iron and recognition rate by other Pseudomonas strains. An uncommonly high affinity for iron of the pyoverdin synthetized by P. putida BTP1 was observed by comparing both the apparent stability constant and the decomplexation kinetic of its ferric complex with those of ferripyoverdins from other strains. On another hand, results from growth stimulation experiments and labeled ferripyoverdin uptake assays highlighted the very low recognition rate of BTP1 isopyoverdins by membrane receptors of foreign strains. By contrast, P. putida BTP1 was able to utilize a broad spectrum of structurally unrelated exogenous pyoverdins by means of multiple receptors that are likely constitutively expressed in its outer membrane. The unusual traits of its pyoverdin-mediated iron acquisition system should contribute to enlarge the ecological competence of Pseudomonas putida BTP1 in terms of colonization and persistence in the rhizosphere

Étude des aptitudes et des rendements

SYL-000705 = Fascicule 3 ;SYL-000706 = Fascicule 5 ;SYL-000707 = Fascicule 6Fascicule 3 :Travaux pratiques :les échelles et tests d'intelligence -- Fascicule 5 :le rendement scolaire, le bagage instrumental -- Fascicule 6 :L'examen des aptitudes et des rendements lors d'une présomption de pathologie cérébraleinfo:eu-repo/semantics/published

Anaerobic digestion process monitoring: focus on the gas phase using electronic nose technology

Gas phase of four pilot-scale anaerobic reactors was monitored with a gas sensors array, also called electronic nose (e-nose) over three weeks. CH4, CO2, H2S, H2 concentration in the gas phase and biogas production rate were also measured. Reactors were exposed to process disturbances by doubling the organic loading rate and by decreasing the temperature from 38 to 32°C for 24 hours. During these tests, sludge pH and alkalinity were also measured. When organic loading was doubled, no changes were observed in pH and alkalinity, while hydrogen content in gas phase increased by 20% and took 8 hours to recover stable values of 130 ppm. Hydrogen sulphide also increased proportionally to organic loading of the reactors and took two days to return to stable values. Methane and carbon dioxide ratio changed from 1.2 to 0.95. No changes were observed during the temperature drop of the digesters apart from hydrogen concentration which increased sharply several hours. Electronic nose was able to detect variations in organic loading rates for the four anaerobic reactors, with increased signals for higher organic loadings of the pilots. Sensing of gas phase of anaerobic reactors was able to discriminate disorders of operating conditions of anaerobic reactors, especially organic loading.OPTIBIOGA