868 research outputs found
SZE Observables, Pressure Profiles and Center Offsets in Magneticum Simulation Galaxy Clusters
We present a detailed study of the galaxy cluster thermal \ac{sze} signal
and pressure profiles using {\it Magneticum} Pathfinder hydrodynamical
simulations. With a sample of 50,000 galaxy clusters () out to , we find significant
variations in the shape of the pressure profile with mass and redshift and
present a new generalized NFW model that follows these trends. We show that the
thermal pressure at accounts for only 80~percent of the pressure
required to maintain hydrostatic equilibrium, and therefore even idealized
hydrostatic mass estimates would be biased at the 20~percent level. We compare
the cluster \ac{sze} signal extracted from a sphere with different virial-like
radii, a virial cylinder within a narrow redshift slice and the full light
cone, confirming small scatter () in the sphere and
showing that structure immediately surrounding clusters increases the scatter
and strengthens non self-similar redshift evolution in the cylinder.
Uncorrelated large scale structure along the line of sight leads to an increase
in the \ac{sze} signal and scatter that is more pronounced for low mass
clusters, resulting in non self-similar trends in both mass and redshift and a
mass dependent scatter that is at low masses. The scatter
distribution is consistent with log-normal in all cases. We present a model of
the offsets between the center of the gravitational potential and the \ac{sze}
center that follows the variations with cluster mass and redshift.Comment: 20 pages, 15 figures, submitted to MNRA
Den gode sædcelle... En antropologisk analyse af arbejdet med sædkvalitet.
THE GOOD SPERM CELL … | Questions about who has the right to be pregnant, and with whom, and which children should be allowed to be born are fundamentally political and normative. However, when fertilization involves reproductive tech nologies these normative questions are often translated into questions of quality whereby they come to appear technical. This becomes clear in thework to ensure “good sperm quality”. Sperm quality is measured both at a population level, in connection to fertility treatment of infertile men, in the recruitment of sperm donors and in connection with attempts to produce so-called artificial sperm. What is regarded as good quality is not only based on “medical evidence” but also on beliefs about what is wished for and what is not. Put differently, medical evidence is produced in light of specifically desired outcomes. This article asks how one determines sperm quality and what kind of practices and normative choices this evaluative process involves. The article builds on medical literature, fieldwork at both a laboratory dealing with sperm analysis and at sperm banks and on interviews with scientists working on the development of artificial sperm
Optimized Approach for Determination of the Solid Temperature in a Steam Turbine in Warm-Keeping-Operation
International audienceThe determination of the temperature distribution in the thick-walled components in steam turbines is increasing in relevance. Due to the growing share of volatile renewable power generation, power plants with a high flexibility and a high integral efficiency are required. e current operational conditions lead to high thermal stresses inside the heavy components and thus to a reduced lifetime. To improve the ability for a fast start-up, the steam turbine can be kept warm during a longer period of stand still. Therefore, information about the metal temperature inside the rotor and the casing are crucial. However, the temperature distribution of the inner casing and especially the rotor cannot be measured without high additional effort. us, a calculation model with sufficient accuracy and also manageable calculation effort is required. In the present work, a hybrid-numerical FEM and analytical-approach has been developed to calculate the solid body temperatures of a steam turbine in warm-keeping operation in a most efficient way. The presented model provides accuracy of nearly % compared with Conjugate-Heat-Transfer simulations with a simultaneously reduced calculation effort by a factor of more than
Occurrence and Distribution of Moganite and Opal-CT in Agates from Paleocene/Eocene Tuffs, El Picado (Cuba)
Agates in Paleocene/Eocene tuffs from El Picado/Los Indios, Cuba were investigated to characterize the mineral composition of the agates and to provide data for the reconstruction of agate forming processes. The volcanic host rocks are strongly altered and fractured and contain numerous fissures and veins mineralized by quartz and chalcedony. These features indicate secondary alteration and silicification processes during tectonic activities that may have also resulted in the formation of massive agates. Local accumulation of manganese oxides/hydroxides, as well as uranium (uranyl-silicate complexes), in the agates confirm their contemporaneous supply with SiO2 and the origin of the silica-bearing solutions from the alteration processes. The mineral composition of the agates is characterized by abnormal high bulk contents of opal-CT (>6 wt%) and moganite (>16 wt%) besides alpha-quartz. The presence of these elevated amounts of “immature” silica phases emphasize that agate formation runs through several structural states of SiO2 with amorphous silica as the first solid phase. A remarkable feature of the agates is a heterogeneous distribution of moganite within the silica matrix revealed by micro-Raman mapping. The intensity ratio of the main symmetric stretching-bending vibrations (A1 modes) of alpha-quartz at 465 cm−1 and moganite at 502 cm−1, respectively, was used to depict the abundance of moganite in the silica matrix. The zoned distribution of moganite and variations in the microtexture and porosity of the agates indicate a multi-phase deposition of SiO2 under varying physico-chemical conditions and a discontinuous silica supply
Chemical and Molecular Variations in Commercial Epoxide Photoresists for X-ray Lithography
The quality of high aspect ratio microstructures fabricated by deep X-ray lithography is highly dependent on the photoresist material used and the process parameters applied. Even with photoresists more suitable to this process, it is common to face defects in the final optical components, such as in case of X-ray gratings. The gratings need to be fabricated with critical dimensions on a sub-micrometer and micrometer scale, with periods of few micrometers and heights of hundreds of micrometers to be used in X-ray imaging techniques such as Talbot–Lau Interferometry. During the fabrication process, these features lead to challenges such as mechanical stability, homogeneity, and defect-free grating patterns. Usually, an epoxy-based negative photoresist is used in X-ray lithography, which needs to account for the shrinkage that takes place during polymer crosslinking in order to avoid defects in the final pattern. Nowadays, photoresist material still lacks certain suitable properties (chemical and mechanical) to fabricate gratings of high quality and with acceptable reproducibility. This work presents the results of TGA, FTIR, and MALDI-TOF analysis made on photoresists commercially available and suitable for X-ray lithography. The photoresists presented different profiles regarding the solvent content and oligomers composition, and in the case of some samples, there were high amounts of non-epoxidized oligomer
- …