Exploration of WEB resources in the domain of metal processing technologies

The amount of information contained in the WEB grows in a galloping way, which is caused by the spread of Internet access and lowering the cost of storing and sharing data across the network. The vast amount of data, impossible to be analyzed by human, is the reason why finding and selecting valuable information has become a serious problem. Due to this situation, a highly useful and desired solution would be the development of a system that would allow continuous monitoring of the WEB and finding for the user valuable information from the selected Internet resources. This paper describes the concept of such a system, along with its initial implementation and application to search for information in the field of foundry industry

Inner disk clearing around the Herbig Ae star HD\,139614: Evidence for a planet-induced gap ?

Spatially resolving the inner dust cavity of the transitional disks is a key to understanding the connection between planetary formation and disk dispersal. The disk around the Herbig star HD 139614 is of particular interest since it presents a pretransitional nature with an au-sized gap, in the dust, that was spatially resolved by mid-IR interferometry. Using new NIR interferometric observations, we aim to characterize the 0.1-10~au region of the HD~139614 disk further and identify viable mechanisms for the inner disk clearing. We report the first multiwavelength radiative transfer modeling of the interferometric data acquired on HD~139614 with PIONIER, AMBER, and MIDI, complemented by Herschel/PACS photometries. We confirm a gap structure in the um-sized dust, extending from about 2.5 au to 6 au, and constrained the properties of the inner dust component: e.g., a radially increasing surface density profile, and a depletion of 10^3 relative to the outer disk. Since self-shadowing and photoevaporation appears unlikely to be responsible for the au-sized gap of HD~139614, we thus tested if dynamical clearing could be a viable mechanism using hydrodynamical simulations to predict the gaseous disk structure. Indeed, a narrow au-sized gap is expected when a single giant planet interacts with the disk. Assuming that small dust grains are well coupled to the gas, we found that a ~ 3~Mjup planet located at 4.5 au from the star could, in less than 1 Myr, reproduce most of the aspects of the dust surface density profile, while no significant depletion in gas occurred in the inner disk, in contrast to the dust. However, the dust-depleted inner disk could be explained by the expected dust filtration by the gap and the efficient dust growth/fragmentation in the inner disk regions. Our results support the hypothesis of a giant planet opening a gap and shaping the inner region of the HD~139614 disk.Comment: Version accepted in A&A, with typos corrections in the tex

Multi-wavelength VLTI study of the puffed-up inner rim of a circumbinary disc

The presence of stable, compact circumbinary discs of gas and dust around post-asymptotic giant branch (post-AGB) binary systems has been well established. We focus on one such system: IRAS 08544-4431. We present an interferometric multi-wavelength analysis of the circumstellar environment of IRAS 08544-4431. The aim is to constrain different contributions to the total flux in the H, K, L, and N-bands in the radial direction. The data from VLTI/PIONIER, VLTI/GRAVITY, and VLTI/MATISSE range from the near-infrared, where the post-AGB star dominates, to the mid-infrared, where the disc dominates. We fitted two geometric models to the visibility data to reproduce the circumbinary disc: a ring with a Gaussian width and a flat disc model with a temperature gradient. The flux contributions from the disc, the primary star (modelled as a point-source), and an over-resolved component are recovered along with the radial size of the emission, the temperature of the disc as a function of radius, and the spectral dependencies of the different components. The trends of all visibility data were well reproduced with the geometric models. The near-infrared data were best fitted with a Gaussian ring model while the mid-infrared data favoured a temperature gradient model. This implies that a vertical structure is present at the disc inner rim, which we attribute to a rounded puffed-up inner rim. The N-to-K size ratio is 2.8, referring to a continuous flat source, analogues to young stellar objects. By combining optical interferometric instruments operating at different wavelengths we can resolve the complex structure of circumstellar discs and study the wavelength-dependent opacity profile. A detailed radial, vertical, and azimuthal structural analysis awaits a radiative transfer treatment in 3D to capture all non-radial complexity.Comment: 8 pages, 5 figures, accepted for publication in A&A Letter

Electrical and Mechanical Properties of Plated Ni/Cu Contacts for Si Solar Cells

AbstractPlated Ni/Cu/Ag contacts are an industrially feasible metallization approach for high efficiency c-Si solar cells with low surface doping concentrations (1018 cm-3 < ND < 1020 cm-3). The 2d-simulations of this work define the minimum requirements on the contact resistivity of metal contacts in a high efficiency solar cell design. The following experimental study of the contact resistivity of plated Ni/Cu/Ag contacts on lowly doped phosphorus emitter demonstrates low contact resistivities in the mΩcm2 regime, which enable solar cells with high fill factors. Furthermore, the paper analyzes the influence of the thermal silicidation process on pseudo-fill factor losses and on the mechanical contact adhesion. The contact adhesion is also studied with respect to the laser contact opening process. The results of this work demonstrate that the right choice of back-end processes enable plated Ni/Cu/Ag contacts with low contact resistivities in combination with high contact adhesions above 1 N/mm

The very compact dust disk in the Red Rectangle

We aim to study the dust distribution in the central regions of the Keplerian disk of the Red Rectangle, the prototype of binary post-AGB stars with rotating circumbinary disks, and to compare it with the distribution of relevant molecular gas tracers We present new high-resolution (20 milliarcseconds, mas) ALMA observations of continuum and line emissions at 0.9 mm. The maps have been analyzed by means of a simple model of dust and free-free emissionn that is able to reproduce the continuum data. Resuts: i) We find that most of the dust emission in the Red Rectangle is concentrated in the inner disk regions, with a typical size of 250 AU in diameter and 50 AU in width. ii) The settlement of dust grains onto inner equatorial regions is remarkable when compared with the relatively widespread gas distribution. iii) This region is basically coincident with the warm PDR (photo-dominated region) where CI, CII, and certain molecules such as HCN are presumably formed, as well as probably PAHs (polycyclic aromatic hydrocarbons, whose emission is very strong in this source). iv) We confirm the large size of the grains, with a typical radius ~ 150 mu The opacity of dust at 0.9 mm is deduced to be relatively large, ~0.5. v) We also confirm the existence of a very compact HII region in the center, for which we measure an extent of 10 - 15 mas (~ 10 AU) and a total flux of 7 - 8 mJy at 0.9 mm.Comment: 5 pages, 4 figures, accepted by Astronomy and Astrophysics Letter

OPTIMIZATION OF SIMULATION MODEL PARAMETERS FOR SOLIDIFICATION OF METALS WITH USE OF AGENT-BASED EVOLUTIONARY ALGORITHM

The finite elements method (FEM) is currently widely used for simulation of thermal processes.However, one of still unresolved problems remains proper selection of mathematicalmodel parameters for these processes. As far as modelling of cooling casts in forms is concerned,particular difficulties appear while estimating values of numerous coefficients suchas: heat transport coefficient between metal and form, specific heat, metal and form heatconduction coefficient, metal and form density. Coefficients mentioned above depend not onlyon materials properties but also on temperature. In the paper the idea of optimalizationof simulation method parameters based on adaptive adjustment of curve representing simulationresult and result obtained in physical experiment is presented along with the ideaof evolutionary and agent-based evolutionary optimization system designed to conduct suchoptimizations. Preliminary results obtained with use of ABAQUS system available in ACKCYFRONET and software developed at AGH-UST conclude the paper

Sparse aperture masking interferometry survey of transitional discs: Search for substellar-mass companions and asymmetries in their parent discs

This is the author accepted manuscript. The final version is available from EDP Sciences via the DOI in this record.Context. Transitional discs are a class of circumstellar discs around young stars with extensive clearing of dusty material within their inner regions on 10s of au scales. One of the primary candidates for this kind of clearing is the formation of planet(s) within the disc that then accrete or clear their immediate area as they migrate through the disc. Aims. The goal of this survey was to search for asymmetries in the brightness distribution around a selection of transitional disc targets. We then aimed to determine whether these asymmetries trace dynamically-induced structures in the disc or the gap-opening planets themselves. Methods. Our sample included eight transitional discs. Using the Keck/NIRC2 instrument we utilised the Sparse Aperture Masking (SAM) interferometry technique to search for asymmetries indicative of ongoing planet formation. We searched for close-in companions using both model fitting and interferometric image reconstruction techniques. Using simulated data, we derived diagnostics that helped us to distinguish between point sources and extended asymmetric disc emission. In addition, we investigated the degeneracy between the contrast and separation that appear for marginally resolved companions. Results. We found FP Tau to contain a previously unseen disc wall, and DM Tau, LkHα330, and TW Hya to contain an asymmetric signal indicative of point source-like emission. We placed upper limits on the contrast of a companion in RXJ1842.9-3532 and V2246 Oph. We ruled the asymmetry signal in RXJ1615.3-3255 and V2062 Oph to be false positives. In the cases where our data indicated a potential companion we computed estimates for the value of McM˙ c and found values in the range of 10−5 − 10−3M2 J yr−1 . Conclusions. We found significant asymmetries in four targets. Of these, three were consistent with companions. We resolved a previously unseen gap in the disc of FP Tau extending inwards from approximately 10 au.We acknowledge support from a STFC Rutherford Fellowship and Grant (ST/J004030/1, ST/K003445/1), Marie Sklodowska-Curie CIG grant (Ref. 618910), and Philip Leverhulme Prize (PLP-2013-110). We additionally acknowledge support from NASA KPDA grants (JPL-1452321, 1474717, 1485953, 1496788). The authors wish to recognise and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. Some of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundatio