Context. Physical characterization of trans-Neptunian objects, a primitive population of the outer solar system, may provide constraints on their formation and evolution. Aims. The goal of this work ...is to characterize a set of 15 scattered disk (SDOs) and detached objects, in terms of their size, albedo, and thermal properties. Methods. Thermal flux measurements obtained with the Herschel-PACS instrument at 70, 100 and 160 mu m, and whenever applicable, with Spitzer-MIPS at 24 and 70 mu m, are modeled with radiometric techniques, in order to derive the objects' individual size, albedo and when possible beaming factor. Error bars are obtained from a Monte-Carlo approach. We look for correlations between these and other physical and orbital parameters. Results. Diameters obtained for our sample range from 100 to 2400 km, and the geometric albedos (in V band) vary from 3.8% to 84.5%. The unweighted mean V geometric albedo for the whole sample is 11.2% (excluding Eris); 6.9% for the SDOs, and 17.0% for the detached objects (excluding Eris). We obtain new bulk densities for three binary systems: Ceto/Phorcys, Typhon/Echidna and Eris/Dysnomia. Apart from correlations clearly due to observational bias, we find significant correlations between albedo and diameter (more reflective objects being bigger), and between albedo, diameter and perihelion distance (brighter and bigger objects having larger perihelia). We discuss possible explanations for these correlations.
A newly developed strain rate dependent anisotropic continuum model is proposed for impact and blast applications in masonry. The model presented adopts the conventional approach of considering ...different yield criteria in tension and compression. The analysis of unreinforced block work masonry walls subjected to impact was performed to evaluate model performance. Comparison of the numerical predictions and test data revealed good agreement. Next, a parametric study was conducted to evaluate the influence of the tensile strengths in the three orthogonal directions and of the wall thickness on the global behavior of masonry walls.
•A strain rate dependent anisotropic continuum model for masonry is proposed.•The numerical simulation of responses of unreinforced masonry walls is performed to validate the capability of the model.•The influence of tensile strength on maximum deflection and crack patterns of the masonry wall is evaluated.•At higher strain rates, the use of proper material properties according to the actual strain rate is recommended.
Context. The Herschel open time key programme TNOs are Cool: A survey of the trans-Neptunian region aims to derive physical and thermal properties for a set of similar to 140 Centaurs and ...trans-Neptunian objects (TNOs), including resonant, classical, detached and scattered disk objects. One goal of the project is to determine albedo and size distributions for specific classes and the overall population of TNOs. Aims. We present Herschel-PACS photometry of 18 Plutinos and determine sizes and albedos for these objects using thermal modeling. We analyze our results for correlations, draw conclusions on the Plutino size distribution, and compare to earlier results. Methods. Flux densities are derived from PACS mini scan-maps using specialized data reduction and photometry methods. In order to improve the quality of our results, we combine our PACS data with existing Spitzer MIPS data where possible, and refine existing absolute magnitudes for the targets. The physical characterization of our sample is done using a thermal model. Uncertainties of the physical parameters are derived using customized Monte Carlo methods. The correlation analysis is performed using a bootstrap Spearman rank analysis. Results. We find the sizes of our Plutinos to range from 150 to 730 km and geometric albedos to vary between 0.04 and 0.28. The average albedo of the sample is 0.08 +/- 0.03, which is comparable to the mean albedo of Centaurs, Jupiter family comets and other TNOs. We were able to calibrate the Plutino size scale for the first time and find the cumulative Plutino size distribution to be best fit using a cumulative power law with q = 2 at sizes ranging from 120-400 km and q = 3 at larger sizes. We revise the bulk density of 1999 TC36 and find (sic) = 0.64(-0.11)(+0.15) g cm(-3). On the basis of a modified Spearman rank analysis technique our Plutino sample appears to be biased with respect to object size but unbiased with respect to albedo. Furthermore, we find biases based on geometrical aspects and color in our sample. There is qualitative evidence that icy Plutinos have higher albedos than the average of the sample.
The present study proposes a dynamic constitutive material interface model that includes non-associated flow rule and high strain rate effects, implemented in the finite element code ABAQUS as a user ...subroutine. First, the model capability is validated with numerical simulations of unreinforced block work masonry walls subjected to low velocity impact. The results obtained are compared with field test data and good agreement is found. Subsequently, a comprehensive parametric analysis is accomplished with different joint tensile strengths and cohesion, and wall thickness to evaluate the effect of the parameter variations on the impact response of masonry walls.
•A dynamic constitutive interface model is proposed.•Numerical simulations of impact response of masonry walls are conducted to validate the model capability.•The influence of tensile strength on high strain rate response of the walls is more significant than the cohesion.•The use of a zero dilatancy in case of a localized impact load leads to localized failure with shear sliding between the blocks.
Abstract
We present broad-band photometry of 11 planetary transits of the hot Jupiter WASP-74 b, using three medium-class telescopes and employing the telescope-defocusing technique. Most of the ...transits were monitored through I filters and one was simultaneously observed in five optical (U, g′, r′, i′, z′) and three near-infrared (J, H, K) passbands, for a total of 18 light curves. We also obtained new high-resolution spectra of the host star. We used these new data to review the orbital and physical properties of the WASP-74 planetary system. We were able to better constrain the main system characteristics, measuring smaller radius and mass for both the hot Jupiter and its host star than previously reported in the literature. Joining our optical data with those taken with the HST in the near infrared, we built up an observational transmission spectrum of the planet, which suggests the presence of strong optical absorbers, as TiO and VO gases, in its atmosphere.
This paper presents numerical and experimental results of a prototype tool that includes blank-holder elements of variable stiffness. The application is developed for high-strength steel applications ...aiming to achieve improvements in the forming operation, namely expand the limits of formability for the tested materials. A numerical model was built including material constitutive models description for the high-strength steel grades used while a forming tool was designed and constructed in order to evaluate the proposed concept. The obtained experimental and numerical results show a positive geometry control and reduction of failure risk. These results are a contribution to the validation of a variable-stiffness blank-holder concept for this particular case study.
This data paper presents lightcurves of 101 near Earth asteroids (NEAs) observed mostly between 2014 and 2017 as part of the EURONEAR photometric survey using 11 telescopes with diameters between 0.4 ...and 4.2 m located in Spain, Chile, Slovakia and Romania. Most targets had no published data at the time of observing, but some objects were observed in the same period mainly by B. Warner, allowing us to confirm or improve the existing results. To plan the runs and select the targets, we developed the public
Long Planning
tool in PHP. For preliminary data reduction and rapid follow-up planning we developed the
LiDAS
pipeline in Python and IRAF. For final data reduction, flux calibration, night linkage and Fourier fitting, we used mainly
MPO Canopus
. Periods of 18 targets are presented for the first time, and we could solve or constrain rotation for 16 of them. We secured periods for 45 targets (
U
∼
3
), found candidate periods for other 16 targets (
U
∼
2
), and we propose tentative periods for other 32 targets (
U
∼
1
). We observed 7 known or candidate binary NEAs, fiting 3 of them (2102 Tantalus, 5143 Heracles and 68348). We observed 8 known or candidate tumbling NEAs, deriving primary periods for 3 objects (9400, 242708 and 470510). We evidenced rapid oscillations (few minutes) and could fit fast tentative periods
TP
2 for 5 large newly suggested tumbling or binary candidates (27346, 112985, 285625, 377732, 408980), probably discovering at least one new binary NEA (2011 WO41). We resolved periods of 4 special objects which include two proposed space mission targets (163249 and 101955 Bennu), one very fast rotator NEA discovered by EURONEAR (2014 NL52) and the “Halloween asteroid” (2015 TB145). Using Mercator in simultaneous 3 band MAIA imaging, we could evidence for the first time clear variation in the color lightcurves of 10 NEAs. The periods derived from the
g
–
r
color lightcurves are found to match individual band period fits for 4 NEAs (27346, 86067, 112985 and 275976).
We present the analysis of stellar binary microlensing event OGLE-2015-BLG-0060 based
on observations obtained from 13 different telescopes. Intensive coverage of the anomalous
parts of the light ...curve was achieved by automated follow-up observations from the robotic
telescopes of the Las Cumbres Observatory. We show that, for the first time, all main features of
an anomalous microlensing event are well covered by follow-up data, allowing us to estimate
the physical parameters of the lens. The strong detection of second-order effects in the event
light curve necessitates the inclusion of longer-baseline survey data in order to constrain
the parallax vector. We find that the event was most likely caused by a stellar binary-lens
with masses M ͙(1) = 0.87 ± 0.12M(☉) and M ͙(2)= 0.77 ± 0.11M(☉). The distance to the lensing
system is 6.41 ± 0.14 kpc and the projected separation between the two components is
13.85 ± 0.16 au. Alternative interpretations are also considered.
The non-linear behavior of uniform-size cellular foams made of aluminum is investigated when subjected to compressive loads while comparing numerical results obtained in the Finite Element Method ...software (FEM) ANSYS workbench and ANSYS Mechanical APDL (ANSYS Parametric Design Language). The numerical model is built on AUTODESK INVENTOR, being imported into ANSYS and solved by the Newton–Raphson iterative method. The most similar conditions were used in ANSYS mechanical and ANSYS workbench, as possible. The obtained numerical results and the differences between the two programs are presented and discussed
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