Dynamic Aspects and Controllability of the MELiSSA Project: A Bioregenerative System to Provide Life Support in Space

Manmade ecosystems differ from their prototype biosphere by the principle of control. The Earth Biosphere is sustainable by stochastic control and very large time constants. By contrast, in a closed ecosystem such as the micro-ecological life support system alternative (MELiSSA system) developed by the European Space Agency for space exploration, a deterministic control is a prerequisite of sustainable existence. MELiSSA is an integrated sum of interconnected biological subsystems. On one hand, all unit operations in charge of the elementary functions constitutive of the entire life support system are studied until a thorough understanding and mathematical modelling. On the other hand, the systemic approach of complex, highly branched systems with feedback loops is performed. This leads to study in the same perspective, with the same degree of accuracy and with the same language, waste degradation, water recycling, atmosphere revitalisation and food production systems prior to the integration of knowledge-based control models. This paper presents the mathematical modelling of the MELiSSA system and the interface between the control strategy of the entire system and the control of the bioreactors.     

Calculation of the decision limit (CCalpha) and the detection capability (CCbeta) for banned substances: the imperfect marriage between the quantitative and the qualitative criteria

Initially in the Decision 2002/657/EC the criteria for the calculation of the decision limit (CCalpha) and the detection capability (CCbeta) have been estimated as purely quantitative (alpha-error is 1% and beta-error is 5%). In 2004, the European Commission has issued a document to provide guidance for the interpretation of the 2002/657/EC. In this document it is mentioned that also qualitative criteria should be fulfilled. Therefore, the calculated CCalpha and CCbeta must be verified by using fortified samples. The method should be able to detect/identify the target component in 50% of the cases at CCalpha and in 95% of the cases at CCbeta. Analytical methods for the analysis of nitroimidazoles, nitrofurans and corticosteroids with LC-MS/MS have been validated by fortifying blank samples below and above the MRPL. CCalpha and CCbeta were calculated using the ISO 11843 approach. In addition, the frequency of methodical compliance for the qualitative criteria was determined at each concentration level. It was observed that at the calculated CCalpha and CCbeta levels the qualitative criteria were not fulfilled. It was concluded that the detection capability of the analytical method should be calculated by using decreasing fortification levels at and below the MRPL. A protocol validating methods for banned substances by limiting the number of samples is presented and the qualitative criteria for the assessment of CCalpha and CCbeta were verified based on the same set of data without the need of performing additional validation experiments.     

Gadolinium doped Ceria nanocrystals synthesized from mesoporous silica

Highly crystalline and thermally stable gadolinium doped ceria (GDC) particles have been synthesized by hard template route for the first time. This oxide is being recognized as an intermediate temperature (500–700 °C) electrolyte material for applications in solid-oxide fuel cells. The GDC particles show high crystallinity and nanometric size (2.83 ± 0.05 nm in diameter) and Raman analyses confirm the formation of the solid solution instead of a CeO₂ and Gd₂O₃ mixture. EDX and EELS studies indicate a stoichiometry coherent with the Gd_0.2Ce_0.8O_1.9 phase. The synthesized nanometric powder is expected to be used in solid oxide fuel cells as well as in the catalytic treatment of automobile exhaust fumes.

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Properties and structure of AsTe glasses: (I). Glass-forming ability and related properties

AsTe glasses have been investigated for determining the molecular mechanisms of glass formation and of crystallization. Stable and homogeneous bulk glasses are prepared throughout the range of concentration from 20 to 65 at % As, by using an improved quenching method. GFA (glass-forming ability) is determined with respect to the rate of cooling. Density, microhardness, T_g and ΔC_p at T_g are measured in the whole range of glass formation. Finally a quantitative analysis of the kinetics of crystallization is carried out. It appears that most properties which involve molecular motions exhibit anomalies for As₄₀ Te₆₀ composition (As₂Te₃ is the unique definite compound of the system). So GFA shows a sharp depression for this critical composition; similarly enthalpy and kinetics of crystallization are drastically modified at As₄₀Te₆₀. For Te-rich glasses, crystallization occurs at low temperature by homogeneous nucleation with a small energy of activation. For As-rich glasses, crystallization occurs at much higher temperatures. Above 200°C it is controlled by growth with an high activation energy which indicates deep rearrangements of the relative positions of the atoms by chemical diffusion. A coherent analysis of all the data is developed which shows that important differences of local order exist between amorphous and crystalline states and also between the two well-distinct types of glasses we are dealing with. The aim of paper II is to determine these differences from diffraction data.     

A measurement of K1 (1420) decay branching ratios

The decay branching ratios of K¹⁰ (1420) into K⁺π^?, K⁰π⁺π^? and K¹⁺(892) π^? are measured in the charge exchange reaction $\text{K}{}^{\mathrm{+}}\text{d}\text{→}\text{K}{}^{10}\text{(1420)}\text{pp}{}_{\mathrm{S}}$ using data from a K⁺d bubble chamber experiment at 4.6 GeV/c incident momentum. For the branching ratio $\text{(}\text{K}{}^1\text{(1420) →}\text{K}{}^1\text{(892)π)/(}\text{K}{}^1\text{(1420) →}\text{K}\text{π)}\text{a value of}\text{(0.54 ± 0.16)}$ is obtained. The results are compared with previous measurements.     

Hadronic gauge couplings in meson decays

The branching ratiosR(J→ππρ)≡Γ(J→ππρ)/Γ(J→ππ) for naturalJ ^P mesons have been evaluated under the assumption that theT(J→ππρ) amplitudes are generated by the gauge principle for ρ-mesons originally proposed by Sakurai in his approach to VMD. The ratios are predicted to increase withJ and are compatible with the present-day data. This suggests that the hadronic interactions of the photon proceed exclusively through its hadronic (VMD) component.     

A precise study of the rotational spectrum of formaldehyde H2CO, H2CO, H2CO, H2CO

The rotational spectra of formaldehyde, H₂¹²C¹⁶O and its isotopic species H₂¹³C¹⁶O, H₂¹²C¹⁸O, and H₂¹³C¹⁸O have been investigated in the ground vibrational state in the frequency region between 8 and 460 GHz. For most cases in which measurements of the a-type R- and Q-branch transitions already existed the accuracy of the line position has been improved to about 10 kHz. For H₂¹²C¹⁶O and H₂¹³C¹⁶O a large number of ΔK_a = ±2 transitions were measured with similar accuracy. These new data when combined with all other available data and appropriate weightings lead to a set of ground state parameters which for the first time are compatible with infrared and ultraviolet data. The rotational constants (and 3σ standard deviations) obtained using Watson's A-reduced Hamiltonian are:

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Hydrogen bonding and short contacts in [2,4,6‐tris(trifluoromethyl)phenyl]phosphinic acid

In the title compound, C₉H₄F₉O₂P, molecules are linked by a single O—H...O hydrogen bond into chains related to those in phenylphosphinic acid. There are short intramolecular F...P contacts.