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Recently inaugurated telescopes, such as the MeerKAT radio telescope and the upcoming Rubin Observatory Legacy Survey of Space and Time, will be able to detect millions of transient events in the night sky. Stellar collisions between white dwarfs (WDs) and main-sequence (MS) stars may be detectable among such transients. Simulations will play a key role in characterizing these events and selecting targets for follow-up. We present 3D smoothed particle hydrodynamics models of dynamical interactions between a |$0.6\ {\rm M}_{\odot }$|  WD and 0.3, 0.6, and |$1.2\ {\rm M}_{\odot }$|  MS stars within globular cluster environments. Utilizing a 34-isotope nuclear network, we investigate the energetics, gas morphologies, and mass-loss properties of these collisions for different stellar mass ratios. Our models predict an overabundance of |$^{13}$| C, |$^{15}$| N, and |$^{17}$| O isotopes relative to solar abundances. Moreover, we find that the time-scale of the collisions is too short and maximum temperatures too low for any significant hydrogen burning or triple-alpha reactions to occur. This combined with a negligible production of elements heavier than neon may be key signatures in distinguishing these events from other transient events with similar peak bolometric luminosities (⁠|$\sim\!\! 10^{38}\!\!-\!\!10^{41}$|  erg s |$^{-1}$|⁠). [ABSTRACT FROM AUTHOR]

Context. V1309 Sco is an example of a red nova, a product of the merger between non-compact stars. V1309 Sco is particularly important within the class of red novae due to the abundance of photometric data of the progenitor binary before the merger. Aims. We aim to investigate the spatio-kinematic and chemical properties of the circumstellar environment, including deriving the physical conditions and establishing the origins of the different circumstellar components. Methods. We used radiative transfer modelling of molecular emission in sub-millimetre spectra to examine the properties of the molecular gas, and we used forbidden line diagnostics from optical spectra to constrain the electron density and temperature using forbidden line diagnostics. We compared line intensities from shock models to observations to look for and constrain shocks. Results. We derived a new kinematical distance of 5.6 kpc to the source. The detection of ro-vibrational H2 and sub-millimetre HCO+ emission in 2016 and 2019, respectively, indicate active shock interactions within the circumstellar environment. The velocity profiles of both H2 and HCO+, as well as the moment-1 maps of sub-millimetre CO and 29SiO, indicate a bipolar structure that may be asymmetric. The sub-millimetre and optical molecular emission exhibits temperatures of 35–113 and 200 K, respectively, whilst the atomic gas is much hotter, with temperatures of 5–15 kK, which may be due to shock heating. Conclusions. The detection of a bipolar structure in V1309 Sco indicates further similarities with the structure of another Galactic red nova, V4332 Sgr. It provides evidence that bipolar structures may be common in red novae. All collected data are consistent with V1309 Sco being a kinematically and chemically complex system. [ABSTRACT FROM AUTHOR]

Rotational transitions in vibrationally excited AlO and TiO—two possible precursors of dust—were observed in the 300 GHz range (1 mm wavelength) toward the oxygen-rich asymptotic giant branch (AGB) stars R Dor and IK Tau with ALMA, and vibrationally excited AlO was observed toward the red supergiant VY CMa with the SMA. The J = 11 → 10 transition of TiO in the v = 1 and 2 levels and the N = 9 → 8 transition in the v = 2 level of AlO were identified toward R Dor, the J = 11 → 10 line of TiO was identified in the v = 1 level toward IK Tau, and two transitions in the v = 1 and 2 levels of AlO were identified toward VY CMa. The newly derived high vibrational temperature of TiO and AlO in R Dor of 1800 ± 200 K and prior measurements of the angular extent confirm that the majority of the emission is from a region within ≲2R⋆ of the central star. A full radiative transfer analysis of AlO in R Dor yielded a fractional abundance of ∼3% of the solar abundance of Al. From a similar analysis of TiO a fractional abundance of ∼78% of the solar abundance of Ti was found. The observations provide indirect evidence that TiO is present in a rotating disk close to the star. Further observations in the ground and excited vibrational levels are needed to determine whether AlO, TiO, and TiO2 are seeds of the Al2O3 dust in R Dor, and perhaps in the gravitationally bound dust shells in other AGB stars with low mass-loss rates. [ABSTRACT FROM AUTHOR]

The envelope of the red supergiant VY CMa has long been considered an extreme example of episodic mass loss that is possibly taking place in other cool and massive evolved stars. Recent (sub-)millimeter observations of the envelope revealed the presence of massive dusty clumps within 800 mas of the star and reinforce the picture of drastic mass-loss phenomena in VY CMa. We present new ALMA observations at an angular resolution of 0.1″ and at an unprecedented sensitivity that reveal further details about the dusty clumps. We resolve more discrete features and identify a submillimeter counterpart of a more distant Southwest (SW) Clump known from visual observations. The brightest clump, named C, is marginally resolved in the observations. Gas seen against the resolved continuum emission of clump C produces a molecular spectrum in absorption, in lines of mainly sulfur-bearing species. Except for SW Clump, no molecular emission is found to be associated with the dusty clumps and we propose that the dusty structures have an atypically low gas content. We attempt to reproduce the properties of the dusty clumps through 3D radiative transfer modeling. Although a clump configuration explaining the observations is found, it is not unique. A very high optical depth of all clumps to the stellar radiation makes the modeling very challenging, and requires an unrealistically high dust mass for one of the clumps. We suggest that the dusty features have substructures (e.g., porosity) that allow deeper penetration of stellar photons within the clumps than in a homogeneous configuration. A comparison of the estimated clump ages to variations in the stellar visual flux for over a century suggests that the mechanism responsible for their formation is not uniquely manifested by enhanced or strongly diminished visual light. The study demonstrates that the dusty mass-loss episodes of VY CMa are indeed unparalleled among all known non-explosive stars. The origin of these episodes remains an unsolved problem. [ABSTRACT FROM AUTHOR]

Red novae are optical transients erupting at luminosities typically higher than those of classical novae. Their outbursts are believed to be caused by stellar mergers. We present millimeter/submillimeter-wave observations with the Atacama Large (sub)Millimeter Array (ALMA) and the Submillimeter Array (SMA) of the three best-known Galactic red novae, V4332 Sgr, V1309 Sco, and V838 Mon. The observations were taken 22, 8, and 14 yr after their respective eruptions and reveal the presence of molecular gas at excitation temperatures of 35–200 K. The gas displays molecular emission in rotational transitions with very broad lines (full width ~400 km s−1). We found emission of CO, SiO, SO, SO2 (in all three red novae), H2S (covered only in V838 Mon), and AlO (present in V4332 Sgr and V1309 Sco). No anomalies were found in the isotopic composition of the molecular material, and the chemical (molecular) compositions of the three red novae appear similar to those of oxygen-rich envelopes of classical evolved stars (RSGs, AGBs, post-AGBs). The minimum masses of the molecular material that was most likely dispersed in the red-nova eruptions are 0.05, 0.01, and 10−4M⊙ for V838 Mon, V4332 Sgr, and V1309 Sco, respectively. The molecular outflows in V4332 Sgr and V1309 Sco are spatially resolved and appear bipolar. The kinematic distances to V1309 Sco and V4332 Sgr are 2.1 and 4.2 kpc, respectively. The kinetic energy stored in the ejecta of the two older red-nova remnants of V838 Mon and V4332 Sgr is of the order of 1046 erg, similar to values found for some post-AGB (pre-PN) objects whose bipolar ejecta were also formed in a short-duration eruption. Our observations strengthen the link between these post-AGB objects and red novae and support the hypothesis that some of the post-AGB objects were formed in a common-envelope ejection event or its most catastrophic outcome, a merger. [ABSTRACT FROM AUTHOR]

Context. HCN is a major constituent of the circumstellar envelopes of carbon-rich evolved stars, and rotational lines from within its vibrationally excited states probe parts of these regions closest to the stellar surface. A number of such lines are known to show maser action. Historically, in one of them, the 177 GHz J = 2 → 1 line in the l-doubled bending mode has been found to show relatively strong maser action, with results only published for a single object, the archetypical high-mass loss asymptotic giant branch (AGB) star IRC+10216. Aims. To examine how common 177 GHz HCN maser emission is, we conducted an exploratory survey for this line toward a select sample of carbon-rich asymptotic giant branch stars that are observable from the southern hemisphere. Methods. We used the Atacama Pathfinder Experiment 12 meter submillimeter Telescope (APEX) equipped with a new receiver to simultaneously observe three J = 2 → 1 HCN rotational transitions, the (0; 11c ; 0) and (0; 11d ; 0) l-doublet components, and the line from the (0, 0, 0) ground state. Results. The (0; 11c ; 0) maser line is detected toward 11 of 13 observed sources, which all show emission in the (0, 0, 0) transition. In most of the sources, the peak intensity of the (0; 11c ; 0) line rivals that of the (0, 0, 0) line; in two sources, it is even stronger. Except for the object with the highest mass-loss rate, IRC+10216, the (0; 11c ; 0) line covers a smaller velocity range than the (0, 0, 0) line. The (0; 11d ; 0) line, which is detected in four of the sources, is much weaker than the other two lines and covers a velocity range that is smaller yet, again except for IRC+10216. Compared to its first detection in 1989, the profile of the (0; 11c ; 0) line observed toward IRC+10216 looks very different, and we also appear to see variability in the (0, 0, 0) line profile (at a much lower degree). Our limited information on temporal variabilitydisfavors a strong correlation of maser and stellar continuum flux. Conclusions. Maser emission in the 177 GHz J = 2 → 1 (0; 11c ; 0) line of HCN appears to be common in carbon-rich AGB stars. Like for other vibrationally excited HCN lines, our observations indicate that the origin of these lines is in the acceleration zone of the stellar outflow in which dust is forming. For all the stars toward which we detect the maser line, the number of photons available at 7 and 14 μm, corresponding to transitions to vibrationally excited states possibly involved in its pumping, is found to be far greater than that of the maser photons, which makes radiative pumping feasible. Other findings point to a collisional pumping scheme, however. [ABSTRACT FROM AUTHOR]

A Results of experimental load tests are used for the validation of numerical models applied in analyses of the concrete box bridges by means of the Finite Element Method. Six different models were used in the analyses: two created of 1-dimensional finite elements in a 2- and 3-dimensional space and four hybrid models composed of 1- and 2-dimensional elements in a 3-dimensional space. Validation of the theoretical models was based on the case of a cable-stayed bridge structure (max. span length 256 m) and a continuous multi-span beam structure (max. span length 60 m). Details of the numerical models, results of static and dynamic analyses as well as the procedure and effects of static and dynamic load tests are presented, compared and discussed. [ABSTRACT FROM AUTHOR]

We present optical and infrared spectroscopy of V1309 Sco, an object that erupted in 2008 in a stellar-merger event. During the outburst, V1309 Sco displayed characteristics typical of red transients, a class of objects similar to V838 Mon. Our observations were obtained in 2009 and 2012, i.e. months and years after the eruption of V1309 Sco, and illustrate severe changes in the remnant, mainly in its circumstellar surroundings. In addition to atomic gas observed in earlier epochs, we identified molecular bands of TiO, VO, H2O, ScO, AlO, and CrO. The infrared bands of CrO we analyse are the first astronomical identification of the features. Over the whole period covered by our data, the remnant was associated with a cool (≲1000 K) outflow with a terminal velocity of about 200 km s-1. Signatures of warmer atomic gas, likely to be still dissipating the energy of the 2008 outburst, dramatically decreased their brightness between 2009 and 2012. In addition, the source of optical continuum disappeared sometime before 2012, likely owing to the formation of new dust. The final stage of V1309 Sco's evolution captured by our spectra is an object remarkably similar to an older red transient, V4332 Sgr. In addition to providing a detailed view on the settling of the eruptive object, the observations presented here reinforce the conclusion that all the Galactic red transients are a manifestation of the same phenomenon, i.e. a stellar merger. The late spectra of V1309 Sco also suggest peculiarities in the chemical composition of the remnant, which still need to be explored. [ABSTRACT FROM AUTHOR]

Context. The source V4332 Sgr is a red transient (red nova) whose eruption was observed in 1994. The remnant of the eruption shows a unique optical spectrum: strong emission lines of atoms and molecules superimposed on an M-type stellar spectrum. The stellar-like remnant is not directly observable, however. It is presumably embedded in a disc-like dusty envelope seen almost face-on. The observed optical spectrum is assumed to result from interactions of the central-star radiation with dust and gas in the disc and outflows initiated in 1994. Aims. We aim at studying the optical spectrum of the object in great detail to better understand the origin of the spectrum and the nature of the object. Methods. We reduced and measured a high-resolution (R ≃ 40 000) spectrum of V4332 Sgr obtained with VLT/UVES in April/May 2005. The spectrum comes from the ESO archives and is the best quality spectrum of the object ever obtained. Context. Magnetic fields play an important role in the formation and stabilization of spiral structures in galaxies, but the interaction between interstellar gas and magnetic fields has not yet been understood. In particular, the phenomenon of "magnetic arms" located between material arms is a mystery. Aims. The strength and structure of interstellar magnetic fields and their relation to spiral arms in gas and dust are investigated in the nearby and almost face-on spiral galaxy IC 342. Methods. The total and polarized radio continuum emission of IC 342 was observed with high spatial resolution in four wavelength bands with the Effelsberg and VLA telescopes. At λ6.2 cm the data from both telescopes were combined. I separated thermal and nonthermal (synchrotron) emission components with the help of the spectral index distribution and derived maps of the magnetic field strength, degree of magnetic field order, magnetic pitch angle, Faraday rotation measure, and Faraday depolarization. Results. We identified and measured over 200 emission features belonging to 11 elements and 6 molecules. The continuous, stellar-like component can be classified as ~M3. The radial velocity of the object is ~-75 km s-1 as derived from narrow atomic emission lines. The interstellar reddening was estimated to be 0.35 ≤ EB-V ≤ 0.75. From radial velocities of interstellar absorption features in the NaiD lines, we estimated a lower limit of ~5.5 kpc to the distance of V4332 Sgr. When compared to spectroscopic observations obtained in 2009, the spectrum of V4332 Sgr considerably evolved between 2005 and 2009. The object significantly faded in the optical (by ~2 mag in the V band), which resulted from cooling of the main remnant by 300-350 K, corresponding to its spectral-type change from M3 to M5-6. The object increased in luminosity by ~50%, however, implying a significant expansion of its dimensions. Most of the emission features seen in 2005 significantly faded or even disappeared from the spectrum of V4332 Sgr in 2009. These resulted from fading of the optical central-star radiation and a decrease of the optical thickness of the cirumstellar matter, presumably due to its expansion. V4332 Sgr bears several resemblances to V1309 Sco, which erupted in 2008. This can indicate a similar nature of the eruptions of the two objects. The outburst resulted from merger of a contact binary in V1309 Sco. [ABSTRACT FROM AUTHOR]

Aims. V838 Monocerotis erupted in 2002, brightened in a series of outbursts, and eventually developed a spectacular light echo. A very red star emerged a few months after the outburst. The whole event has been interpreted as the result of a merger. Methods. We obtained near- and mid-IR interferometric observations of V838 Mon with the AMBER and MIDI recombiners located at the Very Large Telescope Interferometer (VLTI) array. The MIDI two-beam observations were obtained with the 8m unit telescopes between October 2011 and February 2012. The AMBER three-beam observations were obtained with the compact array (B ≤ 35 m) in April 2013 and the long array (B ≤ 140 m) in May 2014, using the 1.8m auxiliary telescopes. Results. A significant new result is the detection of a compact structure around V838 Mon, as seen from MIDI data. The extension of the structure increases from a FWHM of 25 mas at 8 μm to 70 mas at 13 μm. At the adopted distance of D = 6.1 ± 0.6 kpc, the dust is distributed from about 150 to 400 AU around V838 Mon. The MIDI visibilities reveal a flattened structure whose aspect ratio increases with wavelength. The major axis is roughly oriented around a position angle of -10°, which aligns with previous polarimetric studies reported in the literature. This flattening can be interpreted as a relic of the 2002 eruption or as caused by the influence of the currently embedded B3V companion. The AMBER data provide a new diameter for the pseudo-photosphere, which shows that its diameter has decreased by about 40% in 10 yr, reaching a radius R• = 750 ± 200 R☉ (3.5 ± 1.0 AU). Conclusions. After the 2002 eruption, which was interpreted as the merging of two stars, it seems that the resulting source is relaxing to a normal state. The nearby environment exhibits an equatorial overdensity of dust up to several hundred AU. [ABSTRACT FROM AUTHOR]

Context. The eruption of V4332 Sgr was observed in 1994. During the outburst, the object became extremely red, so it has been considered as to belong to red transients of the V838 Mon type. Optical spectroscopy obtained a few years after the eruption showed a faint M-type stellar spectrum underlying numerous molecular and atomic emission features. It has recently been suggested that the central object in V4332 Sgr is now hidden in a dusty disc and that the photospheric spectrum of this object observed in the optical results from scattering of the radiation of the central star on dust grains in the circumstellar matter. Recent polarimetric photometry has shown that the optical radiation of the object is indeed strongly polarized. Aims. If it results from scattering on dust grains, the optical continuum of the object is expected to be polarized. The emission features, on the contrary - as observed directly from circumstellar regions - are expected to be unpolarized. We investigate these predictions. Methods. We present and analyse our spectropolarimetric observations of V4332 Sgr obtained with the VLT in the optical region. Results. The optical continuum of V4332 Sgr is linearly polarized with a typical degree of 16.6%. A clear depolarization is observed in the spectral regions where emission features contribute significantly to the observed flux. The only prominent exception is the Ca i λ6573 emission line, which is polarized in 21%. Conclusions. The results of our spectropolarimetric observations are in accord with the proposed geometry of the system and the advocated nature of the observed optical spectrum of V4332 Sgr. The continuum is not seen directly but results from scattering on dust within the disc and polar outflow, while most of the gas emission comes from the polar outflow excited by the radiation field of the central source. Additionally, the observed polarization patterns suggest a stratification of the outflow. [ABSTRACT FROM AUTHOR]

Context. Phosphorus-bearing compounds have only been studied in the circumstellar environments of the asymptotic giant branch star IRC +10 216 and the protoplanetary nebula CRL 2688, both carbon-rich objects, and the oxygen-rich red supergiant VY CMa. The current chemical models cannot reproduce the high abundances of PO and PN derived from observations of VY CMa. No observations have been reported of phosphorus in the circumstellar envelopes of oxygen-rich asymptotic giant branch stars. Aims.We aim to set observational constraints on the phosphorous chemistry in the circumstellar envelopes of oxygen-rich asymptotic giant branch stars, by focussing on the Mira-type variable star IK Tau. Methods. Using the IRAM 30m telescope and the Submillimeter Array, we observed four rotational transitions of PN (J = 2-1; 3-2; 6-5; 7-6) and four of PO (J = 5=2-3=2; 7=2-5=2; 13=2-11=2; 15=2-13=2). The IRAM 30m observations were dedicated line observations, while the Submillimeter Array data come from an unbiased spectral survey in the frequency range 279-355 GHz. Results. We present the first detections of PN and PO in an oxygen-rich asymptotic giant branch star and estimate abundances X(PN=H2) ≈ 3 × 10-7 and X(PO=H2) in the range 0:5-6:0 × 10-7. This is several orders of magnitude higher than what is found for the carbon-rich asymptotic giant branch star IRC +10 216. The diameter (≲0''7) of the PN and PO emission distributions measured in the interferometric data corresponds to a maximum radial extent of about 40 stellar radii. The abundances and the spatial occurrence of the molecules are in very good agreement with the results reported for VY CMa. We did not detect PS or PH3 in the survey. Conclusions. We suggest that PN and PO are the main carriers of phosphorus in the gas phase, with abundances possibly up to several 10-7. The current chemical models cannot account for this, underlining the strong need for updated chemical models that include phosphorous compounds. [ABSTRACT FROM AUTHOR]

The paper presents the concepts of model construction on transmission delays in systems with wireless interfaces using random series of function. It is a new method of modelling that allows us to use probabilistic description of time required to realise tasks in various devices. It also allows us to use time domain delta function series in order to describe the time of transmission of data between transmitter and receiver. In description of delays probability density function is applied. The model also takes into account existence of intermediary network devices that play a significant role in overall budget of delay. [ABSTRACT FROM AUTHOR]

The formation of inorganic dust in circumstellar environments of evolved stars is poorly understood. Spectra of molecules thought to be most important for the nucleation, i.e. A10, TiO, and TiO2, have been recently detected in the red supergiant VYCMa. These molecules are effectively formed in VY CMa and the observations suggest that non-equilibrium chemistry must be involved in their formation and nucleation into dust. In addition to exploring the recent observations of VY CMa, we briefly discuss the possibility of detecting these molecules in the "dust-poor" circumstellar environment of Betelgeuse. [ABSTRACT FROM AUTHOR]

We report the first detection of pure rotational transitions of TiO and TiO2 at (sub-)millimeter wavelengths towards the red supergiant VYCMa. A rotational temperature, Trot, of about 250K was derived for TiO2. Although Trot was not well constrained for TiO, it is likely somewhat higher than that of TiO2. The detection of the Ti oxides confirms that they are formed in the circumstellar envelopes of cool oxygen-rich stars and may be the "seeds" of inorganic-dust formation, but alternative explanations for our observation of TiO and TiO2 in the cooler regions of the envelope cannot be ruled out at this time. The observations suggest that a significant fraction of the oxides is not converted to dust, but instead remains in the gas phase throughout the outflow. [ABSTRACT FROM AUTHOR]

Thyroid gland is a rare site for distant metastases. The aim of this study is to present a rare case of an isolated metastatic clear cell renal cell cancer (ccRCC) in the thyroid gland seven years after left-sided nephrectomy. A neck cancer discovered by clinical examination, diagnosed by ultrasound -guided USG fine-needle biopsy was removed by surgery. Palliative thyroidectomy with consecutive neck radiotherapy was finished without any complications, except a temporary, asymptomatic hypocalcaemia. After six month remission, the patient's general condition deteriorated, multiorgan RCC dissection appeared leading to the patient's death. [ABSTRACT FROM AUTHOR]

We report the first identification of the optical bands of the B2Σ+-X 2S+ system of AlO in the red supergiant VYCMa. In addition to TiO, VO, ScO, and YO, which were recognized in the optical spectrum of the star long time ago, AlO is another refractory molecule which displays strong emission bands in this peculiar star. Simulating the bands of AlO, we derive a rotational temperature of the circumstellar gas of Trot = 700K. By resolving individual rotational components of the bands, we derive the kinematical characteristics of the gas, finding that the emission is centred at the stellar radial velocity and its intrinsic width is 13.5 kms-1 (full width at half maximum). It is the narrowest emission among all (thermal) features observed in VYCMa so far. The temperature and line widths suggest that the emission arises in gas located within ∼20 stellar radii, where the outflow is still being accelerated. This result contradicts equilibrium-chemistry models which predict substantial AlO abundances only to within a few stellar radii. We argue that non-equilibrium models involving propagation of shocks are needed to explain the observations. [ABSTRACT FROM AUTHOR]

Context. The light echo phenomenon that accompanied the 2002 eruption of V838 Mon allows one to study the properties of the diffuse dusty matter in the vicinity of the object. Aims. We are aiming at obtaining estimates of the optical thickness of the circumstellar matter in front of V838 Mon, as well as optical properties of dust grains in the echoing medium. In particular, we are interested in studying whether the echoing medium can be responsible for the observed faintness of the B-type companion of V838 Mon when compared to three B-type stars that are seen in the vicinty of V838 Mon and are believed to be at the same distance as V838 Mon. Methods. We used the V838 Mon light echo images obtained by the Hubble Space Telescope (HST) in different filters and epochs. From the images we derived the total brightness of the echo and its surface brightness. The results of the measurements were compared to model light echoes. Results. The present study allowed us to estimate the optical thickness of the matter in front of the object and the mean cosine value of the scattering angle of dust grains in three HST filters. Conclusions. The optical thickness of the echoing matter is not sufficient to explain the observed difference in brightness between the B-type companion of V838 Mon and the other three B-type stars observed in the vicinity of V838 Mon. Implications of this result are discussed. Our estimate of the mass of the diffuse matter seen in the light echo shows that the matter cannot have resulted from a past mass loss activity of V838 Mon. We probably observe remnants of an interstellar cloud from which V838 Mon and other members of the observed cluster were formed. [ABSTRACT FROM AUTHOR]

This study presents the operation basis of GPS global positioning system and augmentation systems used to increase positioning accuracy. Furthermore, selected measurement results for an EGNOS-augmented GPS receiver positioning are included along with an analysis of GIS measurements accuracy, performed using differential corrections. This analysis takes into consideration the impact of the number of measurement series and satellite constellation on the accuracy of positioning achieved in praxis using the EGNOS system. [ABSTRACT FROM AUTHOR]

Very Large Array observations of the extreme carbon star IRC+10216 at 7 mm wavelength with 40 milli-arcsec resolution resolve the object's radio emission, which forms an almost round uniform disk of 83 milli-arcsec diameter, corresponding to 11 AU (for an assumed distance of 130 pc). We find a brightness temperature of 1630 K for the radio photosphere. Since the emission is optically thick, we can directly estimate IRC+10216's average luminosity, which is 8600 L☉. This value is in excellent agreement with what is predicted from the period-luminosity relation for carbon-rich Miras. Assuming an effective temperature of 2750 K for IRC+10216, it implies an optical photospheric diameter of 3.8 AU. Our precise determination of IRC+10216's proper motion fits the picture presented by far-ultraviolet and far-infrared wavelength observations of its interaction region with the interstellar medium (its "astrosphere"): the star moves roughly in the direction expected from the morphology of the termination shock and its astrotail structures. Calculation of its three dimensional velocity and an analysis of the kinematics of its surrounding interstellar medium (ISM) suggest an appreciable relative velocity of 42 km s-1, which is about half the value discussed in recent studies. This suggests a lower (time-averaged) mass loss rate and/or a higher ISM density than previously assumed. [ABSTRACT FROM AUTHOR]

Many aspects of the evolutionary phase in which asymptotic giant branch stars (AGB stars) are in transition to become planetary nebulae (PNe) remain poorly understood. An important question is how the circumstellar envelopes of AGB stars switch from spherical symmetry to the axially symmetric structures frequently observed in PNe. In many cases, there is clear evidence that the shaping of the circumstellar envelopes of PNe is linked to the formation of jets/collimated winds and their interaction with the remnant AGB envelope. Because of the short timescale of this evolutionary phase, objects are rare, but their identification provides valuable probes for testing evolutionary models. We observed (sub)millimeter CO rotational transitions with the APEX telescope in a small sample of stars hosting high-velocity OH and water masers. These targets are assumed to have recently left the AGB, as indicated by the presence of winds traced by masers with velocities larger than observed during that phase. We carried out observations of several CO lines, ranging from J = 2-1 up to J = 7-6. In IRAS 15452-5459, we detect a fast molecular outflow in the central region of the nebula and estimate a mass-loss rate between 1.2 x 10-4 Mϴ yr-1 (assuming optically thin emission) and 4.9 x 10-4 Mϴ yr-1 (optically thick emission). We model the SED of this target taking advantage of our continuum measurement at 345 GHz to constrain the emission at long wavelengths. For a distance of 2.5 kpc, we estimate a luminosity of 8000 Lϴ and a dust mass of ∼0.01 Mϴ. Through the flux in the [CII] line (158 pm), we calculate a total mass of about 12 Mϴ for the circumstellar envelope, but the line is likely affected by interstellar contamination. [ABSTRACT FROM AUTHOR]

Complex special inspection of an old masonry arch bridge according to the Guideline on Inspection and Condition Assessment of Railway Bridges and numerical analysis of the structure are presented. The guideline summarises recommendations for the step-by-step investigation of railway bridges applying enhanced methods developed during the EU-funded project Sustainable Bridges. For the investigation of the arch barrel, the ballast parameters and the inner structure of the backfill behind the arch barrel a number of various advanced non-destructive and minor-destructive testing methods were applied. Deformation of the structure during load tests was measured using three independent measuring systems: laser vibrometer, LVDT and microwave radar. Results of calculations performed with 2D and 3D models based on FEM are compared with the field load tests. Sensitivity of the ultimate load of the structure to investigated parameters is studied in FE model. Some general conclusions according to methods of testing and modelling of masonry arch bridges are presented and discussed. [ABSTRACT FROM PUBLISHER]

Data processing algorithms are important parts of modern measurement systems. These algorithms are often delivered to the user as complex program and their numerical structure is not known. Therefore also influence of algorithm on processed data accuracy is not known. One of the methods to evaluate uncertainty propagation through algorithm is based on matrix form of algorithm. Coefficient matrix of algorithm represents its numerical operations and it is a basis to algorithm accuracy evaluation. The paper presents a method how to identify this coefficient matrix when algebraic form of the algorithm is known or is difficult to use. Identified matrix form of algorithm is then used to estimate uncertainty propagation through exemplary algorithms. Results are compared with experiments. [ABSTRACT FROM AUTHOR]

We analyze the experimental time series of internal pressure in a four cylinder spark ignition engine. In our experiment, performed for different spark advance angles, apart from the usual cyclic changes of engine pressure we observed additional oscillations. These oscillations are with longer time scales ranging from one to several hundred engine cycles depending on engine working conditions. Based on the pressure time dependence we have calculated the heat released per combustion cycle. Using the time series of heat release to calculate the correlation coarse-grained entropy we estimated the noise level for internal combustion process. Our results show that for a larger spark advance angle the system is more deterministic. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]