Automatic differentiation based nonlinear model predictive control of satellites using magneto-torquers

Satellite control using magneto-torquers represents a control challenge combined with strong nonlinearity, variable dynamics and partial controllability. An automatic differentiation based nonlinear model predictive control (NMPC) algorithm is developed in this work to tackle these issues. Based on the previously developed formulation of NMPC, a novel variable sampling time scheme is proposed to combine with the NMPC algorithm so that both control performance, particularly the response speed when the satellite is far away from the desired position, and the closed-loop stability when the satellite is at its equilibrium position can be comfortably satisfied. The proposed approach is demonstrated through nonlinear simulation of a specific satellite case with satisfactory results obtained

Stability analysis of constrained nonlinear model predictive control with terminal weighting

This paper investigates stability of model predictive control (MPC) for nonlinear constrained systems. New stability results for the MPC algorithms with terminal weighting are proposed using the dynamic programming method, which gives new criteria for choosing state, control and terminal weighting in the performance index to achieve stability of MPC algorithms. Illustrative examples are given to show that by combining this condition with existing ones, much less conservative results can be generated

Automatic differentiation based nonlinear model predictive control of satellites using magneto-torquers

Satellite control using magneto-torquers represents a control challenge combined with strong nonlinearity, variable dynamics and partial controllability. An automatic differentiation based nonlinear model predictive control (NMPC) algorithm is developed in this work to tackle these issues. Based on the previously developed formulation of NMPC, a novel variable sampling time scheme is proposed to combine with the NMPC algorithm so that both control performance, particularly the response speed when the satellite is far away from the desired position, and the closed-loop stability when the satellite is at its equilibrium position can be comfortably satisfied. The proposed approach is demonstrated through nonlinear simulation of a specific satellite case with satisfactory results obtained

GFP expression and flow cytometry analysis of PfMSP1-19Pb_8.7 clone in blood-stages.

<p>The same fields were photographed using bright (left panel) and fluorescence microscopy (right panel). Mature schizont stage (A). Early schizont stage (B). Flow cytometry analysis of blood cells obtained from infected mice with asynchronous infections. Per sample, 10⁶ erythrocytes were analyzed. Dot plots of blood cells were obtained from uninfected (upper line) and PfMSP1-19Pb_8.7-infected (lower line) mice. For counting the number of infected cells the erythrocyte population was selected by size (forward-scatter (FSC) and side-scatter (SSC)) as shown in the left panel. The center panel shows the relative GFP-fluorescence intensity of cells in the R1 region. Fluorescent erythrocytes were selected from region M2. The right panel shows the dot plot of fluorescence intensity versus the size of cells in R1. Fluorescent erythrocytes were selected in R3, non-fluorescent in R2 (C). Correlation between the parasitemia counted by flow cytometry and the parasitemia counted manually in Giemsa stained blood films (D).</p

Generation of mutant <i>P. berghei</i> parasites and PCR analysis.

<p>Organizational maps of plasmid PyrFlu (A), the construction strategy of recombinant vector PyrFlu/PbfMSP-1/ PbM3′ (B), the gene map following the homologous integration of plasmid PyrFlu/PbfMSP-1/ PbM3′ at the MSP1 locus (C). Genomic DNA of PfMSP1-19Pb_8.7 clone (lanes 1–4 and 7) and wild-type <i>P. berghei</i> ANKA (lanes 5–6 and 8) were used as template; Test primers are indicated by arrows. lane 1: amplification of <i>gfp</i> with the primers <i>gfp</i>F/<i>gfp</i>R; lane 2: verification of transfection using primers Tb/Tf; lanes 3 and 5: verification of the wild-type PbMSP-1 locus with the primers Tb5/T-Pb; lanes 4 and 6: verification of the predicted 5′ integration into the PbMSP-1 locus with the primers Tb5/Tf; lanes 7 and 8: verification of the predicted 3′ integration into the PbMSP-1 locus with the primers 3′veF/3′veR; M: base pair ladder (D). Probe PbM for Southern analysis was shown as black bar. The expected sizes of fragments resulting from digestion with HincII are shown. S (<i>Sac</i>I), B (<i>BamH</i>I), A (<i>Apa</i>I), K (<i>Kpn</i>I) and H2(<i>HincII</i>).</p

Parasitemia profiles of the mice in the passive transfer experiment.

<p>Groups of mice were injected with a total amount of 1.5 mg IgG (groups I and II) and 3.0 mg IgG (groups III and IV). (A): the mice in groups I and III were given IgG from adjuvant-only immunized rabbits, while mice in groups II and IV received IgG purified from rabbits immunized with PfCP-2.9 antigen. All mice were challenged with PfMSP1-19Pb_8.7 transgenic parasite. (B): the mice were grouped and passively transferred with IgG in the same way as in (A), but were challenged with wild-type <i>P. berghei</i>.</p

Comparison of parasitemia between the transgenic PfMSP1-19Pb_8.7 parasite and its parental <i>P. berghei</i>.

<p>Two groups of mice (5 mice/group) were infected with 10⁴ erythrocytes harboring either wild-type <i>P. berghei</i> ANKA or PfMSP1-19Pb_8.7 clone. The parasitemia was assessed daily using Giemsa-stained thin smears.</p

Important role of hornblende fractionation in generating the adakitic magmas in Tongling, Eastern China: evidence from amphibole megacryst and cumulate xenoliths and host gabbros

<p>Tongling, in eastern China, is an area well-known for intra-plate adakites. Here, we present the mineral chemistry and zircon U–Pb ages for amphibole cumulate xenoliths, the mineral chemistry of amphibole megacrysts, and the whole–rock chemistry, zircon U–Pb age and Sr–Nd isotopic compositions of host gabbros from Tongling. Zircon U–Pb dating yields a crystallization age of 120.6 ± 1.2 Ma (MSWD = 4.2) for the host gabbros, which are characteristically depleted in high field strength elements (Nb, Ta, and Ti) and enriched in large ion lithophile elements (Ba and Sr), with εNd (t) of −3.00 to −4.52 and initial ⁸⁷Sr/⁸⁶Sr ratios of 0.7068–0.7072, suggesting an enriched mantle source. Parental melts, as estimated from average amphibole megacryst and cumulate compositions, have Mg# values of 26–33, are enriched in Ba, Th, U, and Nd, and depleted in Nb, Ta, Zr, Hf, and Ti, similar to 136 Ma mafic magmas in Tongling. Zircon U–Pb dating yields a crystallization age of 135.4 ± 1.0 Ma (MSWD = 1.6) for the amphibole cumulates. It is concluded that the Tongling adakitic rocks were formed by polybaric crystallization involving early high-pressure intracrustal fractional crystallization of cumulates comprising hornblende and clinopyroxene, and late low-pressure fractional crystallization of hornblende and plagioclase phenocrysts. The flat subduction of Pacific plate and its subsequent foundering during the Cretaceous may have triggered the generation of extensive adakitic magmas and lithospheric thinning in the Lower Yangtze Region.</p

MOESM1 of The adverse vascular effects of multi-walled carbon nanotubes (MWCNTs) to human vein endothelial cells (HUVECs) in vitro: role of length of MWCNTs

Additional file 1. Additional Figures S1–S5

Journal officiel de la Guinée française

15 août 19241924/08/15 (A24,N560)