ABSTRACT
Gravitational waves provide a unique tool for observational astronomy. While the first LIGO–Virgo catalogue of gravitational-wave transients (GWTC-1) contains 11 signals from black hole and ...neutron star binaries, the number of observations is increasing rapidly as detector sensitivity improves. To extract information from the observed signals, it is imperative to have fast, flexible, and scalable inference techniques. In a previous paper, we introduced bilby: a modular and user-friendly Bayesian inference library adapted to address the needs of gravitational-wave inference. In this work, we demonstrate that bilby produces reliable results for simulated gravitational-wave signals from compact binary mergers, and verify that it accurately reproduces results reported for the 11 GWTC-1 signals. Additionally, we provide configuration and output files for all analyses to allow for easy reproduction, modification, and future use. This work establishes that bilby is primed and ready to analyse the rapidly growing population of compact binary coalescence gravitational-wave signals.
Herein, the inverted hybrid solar cells were fabricated with the configuration of FTO/TiO
2
/PFN/P3HT:PC
61
BM:GeS
2
/MoO
3
/Ag. According to our research, it is the first time that nanoparticles of ...germanium sulfide (GeS
2
) have been added into a poly(3-hexylthiophene-2,5-diyl)-based inverted organic solar cell that is also free of ITO by using FTO instead. Some optical and electrical properties were obtained, through UV–Vis spectrum, Raman, J–V curves, quantum efficiency curves and impedance, among others, in order to verify the influence of the addition of GeS
2
in the active layer. From this it was found that GeS
2
, in the polymeric active layer based on P3HT, can improve the energy conversion efficiency in the cell with the configuration showed, reaching an efficiency of 4.20% when 1.00wt% of germanium sulfide was added, in contrast to the efficiency of 3.32% achieved without said compound.
Graphical Abstract
Solar cell squematic representation with the configuration FTO/TiO
2
/P3HT:PC
61
BM:GeS
2
/MoO
3
/Ag
Context.
The census of the globular clusters (GCs) in the Milky Way is still a work in progress. The advent of new deep surveys has made it possible to discover many new star clusters both in the ...Galactic disk and bulge, but many of these new candidates have not yet been studied in detail, leaving a veil on their true physical nature.
Aims.
We explore the nature of 19 new GC candidates in the Galactic bulge by analysing their colour–magnitude diagrams (CMDs) in the near-infrared (NIR) using the VISTA Variables in the Via Láctea Survey (VVV) database. We estimate their main astrophysical parameters: reddening and extinction, distance, total luminosity, mean cluster proper motions (PMs), metallicity, and age.
Methods.
We obtain the cluster catalogues including the likely cluster members by applying a decontamination procedure on the observed CMDs based on the vector PM diagrams from VIRAC2. We adopt NIR reddening maps in order to calculate the reddening and extinction for each cluster, and then estimate the distance moduli and heliocentric distances. Metallicities and ages are evaluated by fitting theoretical stellar isochrones. We also calculate their luminosities in comparison with known Galactic GCs.
Results.
We estimate a wide reddening range of 0.25 ⩽
E
(
J
−
K
s
)⩽2.0 mag and extinction 0.11 ⩽
A
Ks
⩽ 0.86 mag for the sample clusters, as expected in the bulge regions. The range of heliocentric distances is 6.8 ⩽
D
⩽ 11.4 kpc. This allows us to place these clusters between 0.56 and 3.25 kpc from the Galactic centre, assuming
R
⊙
= 8.2 kpc. Also, their PMs are kinematically similar to the typical motion of the Galactic bulge, apart from VVV-CL160, which shows different PMs. We also derive their metallicities and ages, finding −1.40⩽ Fe/H ⩽ 0.0 dex and
t
≈ 8 − 13 Gyr respectively. The luminosities are calculated both in
K
s
- and
V
-bands, recovering −3.4 ⩽
M
V
⩽ −7.5. We also examine the possible RR Lyrae members found in the cluster fields.
Conclusions.
Based on their positions, kinematics, metallicities, and ages, and comparing our results with the literature, we conclude that nine candidates are real GCs, seven need more observations to be fully confirmed as GCs, and three candidates are discarded as GCs and appear to be younger open clusters.
Context.
Globular clusters (GCs) are witnesses of the past accretion events onto the Milky Way. In particular, the GCs of the Sagittarius (Sgr) dwarf galaxy are important probes of an on-going ...merger.
Aims.
Our main goal is to search for new GC members of this dwarf galaxy using the VISTA Variables in the Via Lactea Extended Survey (VVVX) near-infrared database combined with the
Gaia
Early Data Release 3 (EDR3) optical database.
Methods.
We investigated all VVVX-enabled discoveries of GC candidates in a region covering about 180 sq. deg. toward the bulge and the Sgr dwarf galaxy. We used multiband point-spread function photometry to obtain deep color-magnitude diagrams (CMDs) and luminosity functions (LFs) for all GC candidates, complemented by accurate
Gaia
-EDR3 proper motions (PMs) to select Sgr members and variability information to select RR Lyrae which are potential GC members.
Results.
After applying a strict PM cut to discard foreground bulge and disk stars, the CMDs and LFs for some of the GC candidates exhibit well defined red giant branches and red clump giant star peaks. We selected the best Sgr GCs, estimating their distances, reddenings, and associated RR Lyrae.
Conclusions.
We discover 12 new Sgr GC members, more than doubling the number of GCs known in this dwarf galaxy. In addition, there are 11 other GC candidates identified that are uncertain, awaiting better data for confirmation.
The exposure to environmental variations in pH and temperature has proven impacts on benthic ectotherms calcifiers, as evidenced by tradeoffs between physiological processes. However, how these ...stressors affect structure and functionality of mollusk shells has received less attention. Episodic events of upwelling of deep cold and low pH waters are well documented in eastern boundary systems and may be stressful to mollusks, impairing both physiological and biomechanical performance. These events are projected to become more intense, and extensive in time with ongoing global warming. In this study, we evaluate the independent and interactive effects of temperature and pH on the biomineral and biomechanical properties of Argopecten purpuratus scallop shells. Total organic matter in the shell mineral increased under reduced pH (~ 7.7) and control conditions (pH ~ 8.0). The periostracum layer coating the outer shell surface showed increased protein content under low pH conditions but decreasing sulfate and polysaccharides content. Reduced pH negatively impacts shell density and increases the disorder in the orientation of calcite crystals. At elevated temperatures (18 °C), shell microhardness increased. Other biomechanical properties were not affected by pH/temperature treatments. Thus, under a reduction of 0.3 pH units and low temperature, the response of A. purpuratus was a tradeoff among organic compounds (biopolymer plasticity), density, and crystal organization (mineral plasticity) to maintain shell biomechanical performance, while increased temperature ameliorated the impacts on shell hardness. Biopolymer plasticity was associated with ecophysiological performance, indicating that, under the influence of natural fluctuations in pH and temperature, energetic constraints might be critical in modulating the long-term sustainability of this compensatory mechanism.
Asphalt self-healing by encapsulated rejuvenating agents is considered a revolutionary technology for the autonomic crack-healing of aged asphalt pavements. This paper aims to explore the use of ...Bio-Oil (BO) obtained from liquefied agricultural biomass waste as a bio-based encapsulated rejuvenating agent for self-healing of bituminous materials. Novel BO capsules were synthesized using two simple dripping methods through dropping funnel and syringe pump devices, where the BO agent was microencapsulated by external ionic gelation in a biopolymer matrix of sodium alginate. Size, surface aspect, and elemental composition of the BO capsules were characterized by optical and scanning electron microscopy and energy-dispersive X-ray spectroscopy. Thermal stability and chemical properties of BO capsules and their components were assessed through thermogravimetric analysis (TGA-DTG) and Fourier-Transform Infrared spectroscopy (FTIR-ATR). The mechanical behavior of the capsules was evaluated by compressive and low-load micro-indentation tests. The self-healing efficiency over time of BO as a rejuvenating agent in cracked bitumen samples was quantified by fluorescence microscopy. Main results showed that the BO capsules presented an adequate morphology for the asphalt self-healing application, with good thermal stability and physical-chemical properties. It was also proven that the BO can diffuse in the bitumen reducing the viscosity and consequently self-healing the open microcracks.
Polymer-based nanocomposites such as polycaprolactone/graphene oxide (PCL/GO) have emerged as alternatives for bone tissue engineering (BTE) applications. The objective of this research was to ...investigate the impact of a gelatin (Gt) coating on the degradability and different properties of PCL nanofibrous scaffolds fabricated by an electrospinning technique with 1 and 2 wt% GO. Uniform PCL/GO fibers were obtained with a beadless structure and rough surface. PCL/GO scaffolds exhibited an increase in their crystallization temperature (Tc), attributed to GO, which acted as a nucleation agent. Young's modulus increased by 32 and 63% for the incorporation of 1 and 2 wt% GO, respectively, in comparison with neat PCL. A homogeneous Gt coating was further applied to these fibers, with incorporations as high as 24.7 wt%. The introduction of the Gt coating improved the hydrophilicity and degradability of the scaffolds. Bioactivity analysis revealed that the hydroxyapatite crystals were deposited on the Gt-coated scaffolds, which made them different from their uncoated counterparts. Our results showed the synergic effect of Gt and GO in enhancing the multifunctionality of the PCL, in particular the degradability rate, bioactivity, and cell adhesion and proliferation of hGMSC cells, making it an interesting biomaterial for BTE.
Inverted organic photovoltaic solar cells were fabricated with the configuration of FTO/TiO2/ P3HT:PC61BM/MoO3 /Ag. Besides, the influence of transport layers, titanium dioxide and molybdenum ...trioxide, on the performance of solar cells were investigated. These compounds showed excellent optical (around 80% for molybdenum trioxide and 95% for titanium dioxide), electrical (like charge carrier density of 3.3 x1015 cm-3 and 2.5 x1014 cm-3 for titanium and molybdenum, respectively) and structural (anatase and amorphous hexagonal phase for titanium and molybdenum, respectively) properties to be used as transport layers. Also the influence of the thickness of the electron transport layer is studied, as well as the thickness, temperature and heat treatment time of the active layer. The correct selection of TiO2's thickness (70 nm) and active layer's thickness (250 nm) and annealing (at 100 degrees for 8 minutes) can increase the power conversion efficiency. Moreover, the cell fabricated with transport layers and the best conditions found showed a maximum efficiency of 3.3%, which indicates that the titanium dioxide and molybdenum trioxide played a determining role in the solar cell performance.
An increased interest in scientific applications for underground mining, mainly to extend the productive life of open pit mines such as Chuquicamata in Chile, has motivated a growing effort to model ...experimental and theoretically phenomena found in these mines as well as the processes involved in their operation. There is a general consensus that contamination as a result of dilution, a critical problem found in the operation of underground mines, might be reduced by an adequate design of draw point grids and the appropriate handling of them. This requires understanding of the flow of rock fragments and the evolution of the movement zone created by the interaction of multiple draw points. In this paper, we present a theoretical study focused on determining the movement zone created by the interaction of two neighboring draw points operating in alternate mode that simulate those found in a sub-level caving mine. We employ a modified 2D kinematic model that includes a dilation front and assumes that rocks are restricted to move only along streamlines so that we may determine the modification of an isolated movement zone that results from the extraction of material from a neighboring draw point. The volume of extracted material required to initiate the interaction and the location where it occurs are predicted in terms of the material's previously extracted volume, diffusion coefficient, density variations, and extraction rate. The results show that the top surface of the previously isolated movement zone is modified in order to permit the surface to reach greater heights and displace its maximum position closer to the operating draw point. We also find that the regions outside of the operating draw point's isolated movement zone are affected by the interaction and this is confirmed by the deflection of tracer lines. This could have significant negative effects in underground mining operations because dilution, initially located out of range of an operating draw point, might be carried to either the neighboring draw points or the operating draw point's opening, consequently increasing pollution. The results presented can be extrapolated to 3D systems and generalized to other type of flows described by more complex models than a kinematic model.
► The interaction of two neighbor draw points operating alternately is studied based on a modified 2D kinematic model including dilation front. ► A predefined isolated movement zone is modified by the extraction of material from a neighbor draw point. ► The initial shape becomes higher and its maximum moves toward the center of the operating draw point. ► The previous dilated region favors the movement of material located beyond the range of the operating draw point. ► The interaction depends strongly on the separation between neighboring points.
Although the architectural design parameters of 3D-printed polymer-based scaffolds-porosity, height-to-diameter (H/D) ratio and pore size-are significant determinants of their mechanical integrity, ...their impact has not been explicitly discussed when reporting bulk mechanical properties. Controlled architectures were designed by systematically varying porosity (30-75%, H/D ratio (0.5-2.0) and pore size (0.25-1.0 mm) and fabricated using fused filament fabrication technique. The influence of the three parameters on compressive mechanical properties-apparent elastic modulus E
, bulk yield stress σ
and yield strain ε
-were investigated through a multiple linear regression analysis. H/D ratio and porosity exhibited strong influence on the mechanical behavior, resulting in variations in mean E
of 60% and 95%, respectively. σ
was comparatively less sensitive to H/D ratio over the range investigated in this study, with 15% variation in mean values. In contrast, porosity resulted in almost 100% variation in mean σ
values. Pore size was not a significant factor for mechanical behavior, although it is a critical factor in the biological behavior of the scaffolds. Quantifying the influence of porosity, H/D ratio and pore size on bench-top tested bulk mechanical properties can help optimize the development of bone scaffolds from a biomechanical perspective.
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