This paper considers issues related to the assessment of the mechanical properties of elements made with 3D printing technology. To enable experimental testing, an automated test stand was built to ...perform amplitude and phase angle measurements of any point of the specimen. A contactless, optical measurement method was selected, as it is especially adequate when it comes to elements with small dimensions and masses. One innovative element of the test stand is the original method of phase angle measurement using a single vibration sensor fitted with a system forcing and ensuring full measurement synchronization and dynamic state repeatability. Additionally, numerical models of tested objects were produced and simulations of their oscillations were performed. Based on that, the properties of the tested material (PLA) were considered, with a special focus on the density, elastic modulus, and damping. The analyses were conducted for a few elements with different dimensions at different vibration frequencies.
According to the mainstream bioethical stance, death constitutes the termination of an organism. This essay argues that such an understanding of death is inappropriate in the usual context of ...determining death, since it also has a social bearing. There are two reasons to justify this argument. First, the mainstream bioethical definition generates an organismal superposition challenge, according to which a given patient in a single physiological state might be both alive and dead, like Schrödinger's cat. Therefore, there is no clear answer as to whether organ retrieval from a brain-dead patient is an act of killing or not. Second, when combined with the dead donor rule, the mainstream position in the definition of death might lead to ethically unacceptable verdicts, since there is a discrepancy between terminating an organism and depriving someone of moral status.
In a search for common proper motion companions using the VISTA Hemisphere Survey (VHS) and the 2MASS catalogs we have identified a very red (J - K sub(S) = 2.47 mag) late-L dwarf companion of a ...previously unrecognized M dwarf VHS J125601.92-125723.9 (hereafter VHS 1256-1257), located at a projected angular separation of 8''.06 + or - 0''.03. In this work we present a suite of astrometric, photometric, and spectroscopic observations of this new pair in an effort to confirm the companionship and characterize the components. From low-resolution (R ~ 130-600) optical and near-infrared spectroscopy we classified the primary and the companion as M7.5 + or - 0.5 and L7 + or - 1.5, respectively. The primary shows slightly weaker alkali lines than field dwarfs of similar spectral type, but still consistent with either a high-gravity dwarf or a younger object of hundreds of millions of years. The secondary shows spectral features characteristic for low surface gravity objects at ages below several hundred million years, like the peaked triangular shape of the H-band continuum and alkali lines weaker than in field dwarfs of the same spectral type. The absence of lithium in the atmosphere of the primary and the likely kinematic membership to the Local Association allowed us to constrain the age of the system to the range of 150-300 Myr. We report a measurement of the trigonometric parallax pi = 78.8 + or - 6.4 mas, which translates into a distance of 12.7 + or - 1.0 pc; the pair thus has a projected physical separation of 102 + or - 9 AU. We derived the bolometric luminosities of the components and compared them with theoretical evolutionary models to estimate the masses and effective temperatures. For the primary, we determined a luminosity of log(L sub(bol)/L sub(middo t in circle)) = -3.14 + or - 0.10, and inferred a mass of 73 super(+20) sub(-15) M sub(Jup) at the boundary between stars and brown dwarfs and an effective temperature of 2620 + or - 140 K. For the companion we obtained a luminosity of log(L sub(bol)/L sub(middo t in circle)) = -5.05 + or - 0.22 and a mass of 11.2 super(+9.7) sub(-1.8) M sub(Jup), placing it near the deuterium-burning mass limit. The effective temperature derived from evolutionary models is 880 super(+140) sub(-110) K, about 400-700 K cooler than the temperature expected for field late-L dwarfs.
We present the detection and follow-up observations of planetary candidates around low-mass stars observed by the K2 mission. Based on light-curve analysis, adaptive-optics imaging, and optical ...spectroscopy at low and high resolution (including radial velocity measurements), we validate 16 planets around 12 low-mass stars observed during K2 campaigns 5-10. Among the 16 planets, 12 are newly validated, with orbital periods ranging from 0.96 to 33 days. For one of the planets (K2-151b), we present ground-based transit photometry, allowing us to refine the ephemerides. Combining our K2 M-dwarf planets together with the validated or confirmed planets found previously, we investigate the dependence of planet radius Rp on stellar insolation and metallicity Fe/H. We confirm that for periods P 2 days, planets with a radius are less common than planets with a radius between 1-2 R⊕. We also see a hint of the "radius valley" between 1.5 and 2 R⊕, which has been seen for close-in planets around FGK stars. These features in the radius/period distribution could be attributed to photoevaporation of planetary envelopes by high-energy photons from the host star, as they have for FGK stars. For the M dwarfs, though, the features are not as well defined, and we cannot rule out other explanations such as atmospheric loss from internal planetary heat sources or truncation of the protoplanetary disk. There also appears to be a relation between planet size and metallicity: the few planets larger than about 3 R⊕ are found around the most metal-rich M dwarfs.
Malignancy-related hypercalcemia is a leading cause of hypercalcemia among hospitalized patients that carries poor prognosis. Parathyroid carcinoma is a rare form of primary hyperparathyroidism that ...may be associated with PTH dependent hypercalcemia. Severe hypercalcemia is life-threatening and may require management in an intensive care unit by means of medical therapy consisting of volume expansion, loop diuretics, cinacalcet, calcitonin and bisphosphonates. Renal replacement therapy such as intermittent hemodialysis has been successfully used among patients with severe hypercalcemia who become refractory to medical treatment. However, little data are available for cases of severe refractory hypercalcemia that fail to respond to both optimal medical therapy and hemodialysis. Our present case illustrates the successful use of continuous veno-venous hemodiafiltration (CVVHDF) with calcium-free dialysate calcium and markedly increased dialysate flow rate, to restore normal calcemia in a patient with metastatic parathyroid carcinoma with severe refractory hypercalcemia.
44 Validated Planets from K2 Campaign 10 Livingston, John H.; Endl, Michael; Dai, Fei ...
The Astronomical journal,
08/2018, Volume:
156, Issue:
2
Journal Article
Peer reviewed
Open access
We present 44 validated planets from the 10th observing campaign of the NASA K2 mission, as well as high-resolution spectroscopy and speckle imaging follow-up observations. These 44 planets come from ...an initial set of 72 vetted candidates, which we subjected to a validation process incorporating pixel-level analyses, light curve analyses, observational constraints, and statistical false positive probabilities. Our validated planet sample has median values of = , Porb = days, = K, and J = mag. Of particular interest are four ultra-short period planets ( day), 16 planets smaller than 2 , and two planets with large predicted amplitude atmospheric transmission features orbiting infrared-bright stars. We also present 27 planet candidates, most of which are likely to be real and worthy of further observations. Our validated planet sample includes 24 new discoveries and has enhanced the number of currently known super-Earths ( 1-2 ), sub-Neptunes ( 2-4 ), and sub-Saturns ( 4-8 ) orbiting bright stars (J = 8-10 mag) by ∼4%, ∼17%, and ∼11%, respectively.
The aim of this study is to examine the strongly coupled Fluid-Structure Interaction approach as a comprehensive method of predicting the performance of the shock absorber piston valve. For this ...purpose, numerical simulation sand experimental testing are carried out. The coupled CFD-FEA numerical model described in this article, contrary to the attempts made so far, takes into account the influence of contact between valve discs and the initial conditions of the disc stack preload. The model is based on the actual valve geometry used in the shock absorber design. As a result, the described approach is intended for use in industrial applications in development works, in particular, at the conceptual stage. To prove the reliability of the model, two valve compositions are chosen to be measured on a test bench and modelled in FSI simulations. For both of them, a satisfactory level of correlation is achieved, with the correlation error below 10% and well-predicted valve opening points. As a result, it is proved that the 2-way FSI approach has great potential to be successfully used to investigate the damper valve operation. Keywords: shock absorber; Fluid-Structure Interaction; CFD; damping forces; piston valve
HD 3167 is a bright (V = 8.9 mag) K0 V star observed by NASA's K2 space mission during its Campaign 8. It has recently been found to host two small transiting planets, namely, HD 3167b, an ...ultra-short-period (0.96 days) super-Earth, and HD 3167c, a mini-Neptune on a relatively long-period orbit (29.85 days). Here we present an intensive radial velocity (RV) follow-up of HD 3167 performed with the FIES@NOT, HARPS@ESO-3.6 m, and HARPS-N@TNG spectrographs. We revise the system parameters and determine radii, masses, and densities of the two transiting planets by combining the K2 photometry with our spectroscopic data. With a mass of 5.69 0.44 M⊕, a radius of 1.574 0.054 R⊕, and a mean density of , HD 3167b joins the small group of ultra-short-period planets known to have rocky terrestrial compositions. HD 3167c has a mass of M⊕ and a radius of R⊕, yielding a mean density of , indicative of a planet with a composition comprising a solid core surrounded by a thick atmospheric envelope. The rather large pressure scale height (∼350 km) and the brightness of the host star make HD 3167c an ideal target for atmospheric characterization via transmission spectroscopy across a broad range of wavelengths. We found evidence of additional signals in the RV measurements but the currently available data set does not allow us to draw any firm conclusions on the origin of the observed variation.
Context. From a light curve acquired through the K2 space mission, the star K2-111(EPIC 210894022) has been identified as possibly orbited by a transiting planet. Aims. Our aim is to confirm the ...planetary nature of the object and derive its fundamental parameters. Methods. We analyse the light curve variations during the planetary transit using packages developed specifically for exoplanetary transits. Reconnaissance spectroscopy and radial velocity observations have been obtained using three separate telescope and spectrograph combinations. The spectroscopic synthesis package SME has been used to derive the stellar photospheric parameters that were used as input to various stellar evolutionary tracks in order to derive the parameters of the system. The planetary transit was also validated to occur on the assumed host star through adaptive imaging and statistical analysis. Results. The star is found to be located in the background of the Hyades cluster at a distance at least 4 times further away from Earth than the cluster itself. The spectrum and the space velocities of K2-111 strongly suggest it to be a member of the thick disk population. The co-added high-resolution spectra show that that it is a metal poor (Fe/H = − 0.53 ± 0.05 dex) and α-rich somewhat evolved solar-like star of spectral type G3. We find Teff = 5730 ± 50 K, log g⋆ = 4.15 ± 0.1 cgs, and derive a radius of R⋆ = 1.3 ± 0.1 R⊙ and a mass of M⋆ = 0.88 ± 0.02 M⊙. The currently available radial velocity data confirms a super-Earth class planet with a mass of 8.6 ± 3.9 M⊕ and a radius of 1.9 ± 0.2 R⊕. A second more massive object with a period longer than about 120 days is indicated by a long-term radial velocity drift. Conclusions. The radial velocity detection together with the imaging confirms with a high level of significance that the transit signature is caused by a planet orbiting the star K2-111. This planet is also confirmed in the radial velocity data. A second more massive object (planet, brown dwarf, or star) has been detected in the radial velocity signature. With an age of ≳10 Gyr this system is one of the oldest where planets are hitherto detected. Further studies of this planetary system are important since it contains information about the planetary formation process during a very early epoch of the history of our Galaxy.
•Nitrogen-based fuel drying within the oxy-fuel process is analysed.•The energy and economic assessment factors have been calculated.•The energy efficiency increases due to nitrogen-based lignite ...drying by 2.
Methods for drying of hard coal and lignite have a great impact on the economy and the environmental aspects of electricity generation processes. Another contemporary aspect of clean coal electricity production is the process for removing carbon dioxide (CO2). Oxy-fuel combustion seems to be one of the leading technologies here. The nitrogen, which is co-produced with oxygen in an air separation unit (ASU) – the integral element of the oxy-fuel power unit, is traditionally vented to the atmosphere. The main feature of ASU-waste nitrogen is however a near-zero moisture content at near-ambient temperature. Such a gas has a much higher potential for moisture absorption than ambient air, so the waste nitrogen may be effectively used as a drying medium at relatively low drying temperatures. The research being described here is focused on thermodynamic and economic analyses of the application of the nitrogen-based lignite dryer within large, lignite-fired oxy-fuel power unit. Simulation models for the power unit and dryer were built and solved for selected data describing fuel parameters, plant location and so on. Finally, economic assessment factors applying to a nitrogen-based dryer were calculated. The proposal for use of ASU-waste nitrogen has been positively verified from both a thermodynamic and an economic point of view. The calculated increase in overall oxy-fuel power unit net efficiency is ca 1.5%, and the internal rate of return (IRR) calculated from the viewpoint of all capital suppliers is ca 20%.
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