Reconfigurability Analysis Method for Spacecraft Autonomous Control

As a critical requirement for spacecraft autonomous control, reconfigurability should be considered in design stage of spacecrafts by involving effective reconfigurability analysis method in guiding system designs. In this paper, a novel reconfigurability analysis method is proposed for spacecraft design. First, some basic definitions regarding spacecraft reconfigurability are given. Then, based on function tree theory, a reconfigurability modeling approach is established to properly describe system’s reconfigurability characteristics, and corresponding analysis procedure based on minimal cut set and minimal path set is further presented. In addition, indexes of fault reconfigurable degree and system reconfigurable rate for evaluating reconfigurability are defined, and the methodology for analyzing system’s week links is also constructed. Finally, the method is verified by a spacecraft attitude measuring system, and the results show that the presented method cannot only implement the quantitative reconfigurability evaluations but also find the weak links, and therefore provides significant improvements for spacecraft reconfigurability design

Dynamics of Dipoles and Quantum Phases in Noncommutative Coordinates

The dynamics of a spin--1/2 neutral particle possessing electric and magnetic dipole moments interacting with external electric and magnetic fields in noncommutative coordinates is obtained. Noncommutativity of space is interposed in terms of a semiclassical constrained Hamiltonian system. The relation between the quantum phase acquired by a particle interacting with an electromagnetic field and the (semi)classical force acting on the system is examined and generalized to establish a formulation of the quantum phases in noncommutative coordinates. The general formalism is applied to physical systems yielding the Aharonov-Bohm, Aharonov-Casher, He-McKellar-Wilkens and Anandan phases in noncommutative coordinates. Bounds for the noncommutativity parameter theta are derived comparing the deformed phases with the experimental data on the Aharonov-Bohm and Aharonov-Casher phases.Comment: Some clarifications, a new bound on theta and references are adde

Graphene-oxide modified polyvinyl-alcohol as microbial carrier to improve high salt wastewater treatment

This work discussed the preparation and characterization of graphene oxide (GO) modified polyvinyl alcohol (PVA) for bacteria immobilization to enhance the biodegrdation efficiency of saline organic wastewater. GO-PVA material has lamellar structure with higher surface area to support bacterial growth and high salinity tolerance. It significantly stimulated the bacterial population by 1.4 times from 2.07×103 CFU/mL to 5.04×103 CFU/mL, and the microbial structure was also improved for salinity tolerance. Acinetobacter, Pseudomonas and Thermophilic hydrogen bacilli were enriched inside GO-PVA materials for glucose biodegradation. Compared to the CODCr removal efficiency with only PVA as the carrier (52.8%), GO-PVA material had better degradation performance (62.8%). It is proved as a good candidate for bioaugmentation to improve biodegradation efficiency in hypersaline organic wastewater

Identification of Benzo[a]pyrene-metabolizing bacteria in forest soils by using DNA-based stable-isotope probing

DNA-based stable-isotope probing (DNA-SIP) was used in this study to investigate the uncultivated bacteria with benzo[a]pyrene (BaP) metabolism capacities in two Chinese forest soils (Mt. Maoer in Heilongjiang Province and Mt. Baicaowa in Hubei Province). We characterized three different phylotypes with responsibility for BaP degradation, none of which were previously reported as BaP-degrading microorganisms by SIP. In Mt. Maoer soil microcosms, the putative BaP degraders were classified as belonging to the genus Terrimonas (family Chitinophagaceae, order Sphingobacteriales), whereas Burkholderia spp. were the key BaP degraders in Mt. Baicaowa soils. The addition of metabolic salicylate significantly increased BaP degradation efficiency in Mt. Maoer soils, and the BaP-metabolizing bacteria shifted to the microorganisms in the family Oxalobacteraceae (genus unclassified). Meanwhile, salicylate addition did not change either BaP degradation or putative BaP degraders in Mt. Baicaowa. Polycyclic aromatic hydrocarbon ring-hydroxylating dioxygenase (PAH-RHD) genes were amplified, sequenced, and quantified in the DNA-SIP (13)C heavy fraction to further confirm the BaP metabolism. By illuminating the microbial diversity and salicylate additive effects on BaP degradation across different soils, the results increased our understanding of BaP natural attenuation and provided a possible approach to enhance the bioremediation of BaP-contaminated soils

Nanosheets-in-nanotube Co3O4-carbon array design enables stable Li-ion storage

Carbon composite products with different structures have been developed and used as anode for lithium-ion batteries due to the superior elasticity of carbon, which can keep the morphology integrity of the electrode materials in the process of the multiple cycles. Herein, a novel structure of nanosheets-in-nanotube Co 3 O 4 /carbon arrays is fabricated by the method of modified chemical vapor deposition (CVD). The carbon nanotube (CNT) layer acting as an outside coater can efficiently prevent the electrode from fragmentation and consequently ensure its shape integrity. The specific structure shows the ultra-stable cycle life (850 mAh g −1 after 200 cycles at 0.5C) and high rate capability (694 mAh g −1 at 2C). The favorable electrochemical properties are contributed to the combination of the wrapped elastic carbon and the enclosed Co 3 O 4 nanosheets in the lithiation process, which is confirmed by an in situ transmission electron microscope

Bacteria capable of degrading anthracene, phenanthrene, and fluoranthene as revealed by DNA based stable-isotope probing in a forest soil

Information on microorganisms possessing the ability to metabolize different polycyclic aromatic hydrocarbons (PAHs) in complex environments helps in understanding PAHs behavior in natural environment and developing bioremediation strategies. In the present study, stable-isotope probing (SIP) was applied to investigate degraders of PAHs in a forest soil with the addition of individually 13C-labeled phenanthrene, anthracene, and fluoranthene. Three distinct phylotypes were identified as the active phenanthrene-, anthracene- and fluoranthene-degrading bacteria. The putative phenanthrene degraders were classified as belonging to the genus Sphingomona. For anthracene, bacteria of the genus Rhodanobacter were the putative degraders, and in the microcosm amended with fluoranthene, the putative degraders were identified as belonging to the phylum Acidobacteria. Our results from DNA-SIP are the first to directly link Rhodanobacter- and Acidobacteria-related bacteria with anthracene and fluoranthene degradation, respectively. The results also illustrate the specificity and diversity of three- and four-ring PAHs degraders in forest soil, contributes to our understanding on natural PAHs biodegradation processes, and also proves the feasibility and practicality of DNA-based SIP for linking functions with identity especially uncultured microorganisms in complex microbial biota

Landau Diamagnetism in Noncommutative Space and the Nonextensive Thermodynamics of Tsallis

We consider the behavior of electrons in an external uniform magnetic field B where the space coordinates perpendicular to B are taken as noncommuting. This results in a generalization of standard thermodynamics. Calculating the susceptibility, we find that the usual Landau diamagnetism is modified. We also compute the susceptibility according to the nonextensive statistics of Tsallis for (1-q)<<1, in terms of the factorization approach. Two methods agree under certain conditions.Comment: Clarifications and new references. Version to appear in Phys.Lett.