EPIC 219217635: A Doubly Eclipsing Quadruple System Containing an Evolved Binary

We have discovered a doubly eclipsing, bound, quadruple star system in the field of K2 Campaign 7. EPIC 219217635 is a stellar image with $Kp = 12.7$ that contains an eclipsing binary (`EB') with $P_A = 3.59470$ d and a second EB with $P_B = 0.61825$ d. We have obtained followup radial-velocity (`RV') spectroscopy observations, adaptive optics imaging, as well as ground-based photometric observations. From our analysis of all the observations, we derive good estimates for a number of the system parameters. We conclude that (1) both binaries are bound in a quadruple star system; (2) a linear trend to the RV curve of binary A is found over a 2-year interval, corresponding to an acceleration, $\dot \gamma = 0.0024 \pm 0.0007$ cm s$^{-2}$; (3) small irregular variations are seen in the eclipse-timing variations (`ETVs') detected over the same interval; (4) the orbital separation of the quadruple system is probably in the range of 8-25 AU; and (5) the orbital planes of the two binaries must be inclined with respect to each other by at least 25$^\circ$. In addition, we find that binary B is evolved, and the cooler and currently less massive star has transferred much of its envelope to the currently more massive star. We have also demonstrated that the system is sufficiently bright that the eclipses can be followed using small ground-based telescopes, and that this system may be profitably studied over the next decade when the outer orbit of the quadruple is expected to manifest itself in the ETV and/or RV curves.Comment: Accepted for publication in MNRA

Magnetization of a neutron plasma with Skyrme and Gogny forces in the presence of a strong magnetic field

Some thermodynamical magnitudes of interest in a pure neutron plasma are studied within the framework of the non-relativistic Brueckner-Hartree-Fock approximation at finite density and temperature. We use Skyrme and Gogny forces to describe such a neutron plasma and study the main differences that arise in these two effective parametrizations of the nuclear interaction when a strong magnetic field induces a permanent magnetization in the gas. The existence of a non-zero permanent spin polarization in a neutron plasma is explored in the density-temperature parameter space. We find that for moderate temperatures and in the low density range up to densities $\approx 0.5\rho_0$ both parametrizations predict that as density decreases an increasingly strong magnetization is allowed. In the range $0.5 \rho_0 \lesssim \rho \lesssim 3 \rho_0$ there is an approximately constant polarization that can be as big as $\approx 12$ for the maximum allowed interior magnetic field $B \approx 10^{18}$ G. For higher densities there is a dramatic difference in the polarization trend followed by Skyrme an Gogny forces. While the former predict a ferromagnetic phase transition, the Gogny forces prevent it keeping the magnetization below 5%.Comment: 21 pages, 16 figures, 1 tabl

A Fluorescence Approach to Assess the Production of Soluble Microbial Products from Aerobic Granular Sludge under the Stress of 2,4-Dichlorophenol

In this study, a fluorescence approach was used to evaluate the production of soluble microbial products (SMP) in aerobic granular sludge system under the stress of 2,4-dichlorophenol (2,4-DCP). A combined use of three-dimension excitation emission matrix fluorescence spectroscopy (3D-EEM), Parallel factor analysis (PARAFAC), synchronous fluorescence and two-dimensional correlation spectroscopy (2D-COS) were explored to respect the SMP formation in the exposure of different doses of 2,4-DCP. Data implied that the presence of 2,4-DCP had an obvious inhibition on biological nitrogen removal. According to EEM-PARAFAC, two fluorescent components were derived and represented to the presence of fulvic-like substances and humic-like substances in Component 1 and protein-like substances in Component 2. It was found from synchronous fluorescence that protein-like peak presented slightly higher intensity than that of fulvic-like peak. 2D-COS further revealed that fluorescence change took place sequentially in the following order: protein-like fraction > fulvic-like fraction. The obtained results could provide a potential application of fluorescence spectra in the released SMP assessment in the exposure of toxic compound during wastewater treatment

EPIC 220204960: A Quadruple Star System Containing Two Strongly Interacting Eclipsing Binaries

We present a strongly interacting quadruple system associated with the K2 target EPIC 220204960. The K2 target itself is a Kp = 12.7 magnitude star at Teff ~ 6100 K which we designate as "B-N" (blue northerly image). The host of the quadruple system, however, is a Kp = 17 magnitude star with a composite M-star spectrum, which we designate as "R-S" (red southerly image). With a 3.2" separation and similar radial velocities and photometric distances, 'B-N' is likely physically associated with 'R-S', making this a quintuple system, but that is incidental to our main claim of a strongly interacting quadruple system in 'R-S'. The two binaries in 'R-S' have orbital periods of 13.27 d and 14.41 d, respectively, and each has an inclination angle of >89 degrees. From our analysis of radial velocity measurements, and of the photometric lightcurve, we conclude that all four stars are very similar with masses close to 0.4 Msun. Both of the binaries exhibit significant ETVs where those of the primary and secondary eclipses 'diverge' by 0.05 days over the course of the 80-day observations. Via a systematic set of numerical simulations of quadruple systems consisting of two interacting binaries, we conclude that the outer orbital period is very likely to be between 300 and 500 days. If sufficient time is devoted to RV studies of this faint target, the outer orbit should be measurable within a year.Comment: 20 pages, 18 figures, 7 tables; accepted for publication in MNRA

Quasi one dimensional transport in individual electrospun composite nanofibers

We present results of transport measurements of individual suspended electrospun nanofibers Poly(methyl methacrylate)-multiwalled carbon nanotubes. The nanofiber is comprised of highly aligned consecutive multiwalled carbon nanotubes. We have confirmed that at the range temperature from room temperature down to ∼60 K, the conductance behaves as power-law of temperature with an exponent of α ∼ 2.9−10.2. The current also behaves as power law of voltage with an exponent of β ∼ 2.3−8.6. The power-law behavior is a footprint for one dimensional transport. The possible models of this confined system are discussed. Using the model of Luttinger liquid states in series, we calculated the exponent for tunneling into the bulk of a single multiwalled carbon nanotube αbulk ∼ 0.06 which agrees with theoretical predictions

A filtration model for prediction of local flux distribution and optimization of submerged hollow fiber membrane module

© 2015 American Institute of Chemical Engineers. A filtration mathematical model was developed on the basis of complete mass balance and momentum balance for the local flux distribution prediction and optimization of submerged hollow fiber membrane module. In this model, the effect of radial permeate flow on internal flow resistance was considered through a slip parameter obtained from the local flux experiments. The effects of fiber length, inside diameter, and average operating flux on local flux distribution were investigated using this model. The predicted results were in good agreement with the experimental data obtained from literature. It was also found that the asymmetry distribution of local flux could be intensified with the increase of average operating flux and fiber length, but slowed down with the increase of fiber inside diameter. Furthermore, the simulation coupled with energy consumption analysis could efficiently predict and illustrate the relationship between fiber geometry and water production efficiency

Slice-level Detection of Intracranial Hemorrhage on CT Using Deep Descriptors of Adjacent Slices

The rapid development in representation learning techniques such as deep neural networks and the availability of large-scale, well-annotated medical imaging datasets have to a rapid increase in the use of supervised machine learning in the 3D medical image analysis and diagnosis. In particular, deep convolutional neural networks (D-CNNs) have been key players and were adopted by the medical imaging community to assist clinicians and medical experts in disease diagnosis and treatment. However, training and inferencing deep neural networks such as D-CNN on high-resolution 3D volumes of Computed Tomography (CT) scans for diagnostic tasks pose formidable computational challenges. This challenge raises the need of developing deep learning-based approaches that are robust in learning representations in 2D images, instead 3D scans. In this work, we propose for the first time a new strategy to train \emph{slice-level} classifiers on CT scans based on the descriptors of the adjacent slices along the axis. In particular, each of which is extracted through a convolutional neural network (CNN). This method is applicable to CT datasets with per-slice labels such as the RSNA Intracranial Hemorrhage (ICH) dataset, which aims to predict the presence of ICH and classify it into 5 different sub-types. We obtain a single model in the top 4% best-performing solutions of the RSNA ICH challenge, where model ensembles are allowed. Experiments also show that the proposed method significantly outperforms the baseline model on CQ500. The proposed method is general and can be applied to other 3D medical diagnosis tasks such as MRI imaging. To encourage new advances in the field, we will make our codes and pre-trained model available upon acceptance of the paper.Comment: Accepted for presentation at the 22nd IEEE Statistical Signal Processing (SSP) worksho

Improving nutrient removal performance of surface flow constructed wetlands in winter using hardy submerged plant-benthic fauna systems

© 2018 The Royal Society of Chemistry. Constructed wetlands (CWs) have been widely used as an ecological technology for removing nutrients from aquatic ecosystems. However, the treatment efficiency of surface flow constructed wetlands (SFCWs) in winter is generally low. To enhance the nutrient removal performance of SFCWs in winter, we developed a novel hardy submerged plant-benthic fauna system by adding Chironomus riparius (C. riparius) larvae and planting Potamogeton crispus L. in SFCWs. Compared to a system without C. riparius, the paired system greatly enhanced TN and TP removal with the average removal efficiencies of 54.73% and 94.76%, respectively. Furthermore, the paired system improved NO 3- -N removal efficiency by 29.51% and reached NH 4+ -N removal efficiency as high as 86.20% simultaneously. The mass balance analysis indicated that C. riparius larvae enhanced substrate absorption and plant uptake in the CWs. The results of microbial analysis agreed with the nutrient removal performance, showing that C. riparius larvae influence the abundance and community structure of microbes related to N removal. As a whole, this study provides a promising ecological strategy for performance intensification of SFCWs in winter

Improvement of bioavailable carbon source and microbial structure toward enhanced nitrate removal by Tubifex tubifex

© 2018 Elsevier B.V. The research provides new insights into how T. tubifex affects microbe-available organic carbon transformation, microbial community, and related inorganic nitrogen transformation. With different T. tubifex densities under enriched NO3-N concentration with different C/N ratio, the groups with low and high T. tubifex abundance had 17.1% and 27.2% higher TOC concentrations compared to control group under C/N ratio of 3.0 and 2.0, respectively. According to the OC characteristics analyzed by GC–MS and EEM, the group with T. tubifex contained higher dissolved organic carbon (DOC) content and short-chain compounds. As the NO3-N concentration increased and C/N ratio decreased, the proportions of carboxylic acid derivatives (methyl acetate), sulfur-containing compounds, humic-like products and the emission of CO2 were enhanced with T. tubifex, which could be utilized by denitrifiers directly. The OC degradation was highly correlated with the effect of T. tubifex on microbial community and nutrient removal. The T. tubifex can increase OC transformed into sediment and change the microbial community similarity to that in their digestive system. According to the principal component analysis (PCA), the improved proportions of OC that available for microbes and altered microbial community with T. tubifex could enhance denitrification, which experienced a 21% higher denitrifiers and threefold increased NO3-N removal efficiency than that in control group

Characterization of soluble microbial products in a partial nitrification sequencing batch biofilm reactor treating high ammonia nitrogen wastewater

© 2017 In present study, the characterization of soluble microbial products (SMP) was evaluated in a partial nitrification sequencing batch biofilm reactor (SBBR). During the stable operation of SBBR, the NH4+-N removal efficiency and nitrite accumulation ratio were 96.70 ± 0.41% and 93.77 ± 1.04%, respectively. According to excitation-emission matrix (EEM), the intensities of protein-like substances were reduced under anoxic and aerobic phases, whereas humic-like substances had little change during the whole cycle. Parallel factor analysis (PARAFAC) further indentified two components and their fluorescence intensity scores were both reduced. Synchronous fluorescence spectra revealed that the fluorescence intensity of protein-like fraction decreased with reaction time. Two-dimensional correlation spectroscopy (2D-COS) further demonstrated that protein-like fraction might decrease earlier than the other fractions. The information obtained in present study is of fundamental significance for understanding the key components in SMP and their changes in partial nitrification system by using a spectral approach