Reduced Order Models for Profiled Steel Diaphragm Panels

The objective of this paper is to provide progress on development and validation of reduced order models for the in plane strength and stiffness of profiled steel panels appropriate for use in structural models of an entire building. Profiled steel panels, i.e, metal deck, often serve as a key distribution element in building lateral force resisting systems. Acting largely as an in-plane shear diaphragm, metal deck as employed in walls, roofs, and floors plays a key role in creating and driving three-dimensional building response. As structural modeling evolves from two-dimensional frameworks to fully three-dimensional buildings, accurate and computationally efficient models of profiled steel panels are needed. Three-dimensional building response is increasingly required by ever-evolving structural standards, particularly in seismic design, and structural efficiency demands that the benefits of three-dimensional response be leveraged in design. Equivalent orthotropic plate models provide a potential reduced order model for profiled steel panels that is investigated in this paper. A recent proposal for the rigidities in such a model are assessed against shell finite element models of profiled steel panels. In addition, the impact of discrete connections and discrete panels, as occurs in an actual roof system, are assessed when applying these reduced order models. Extension of equivalent orthotropic plate models to elastic buckling and strength, in addition to stiffness, both represent work in progress, but initial results are provided. Examples show that equivalent orthotropic plate models must be used with care to yield useful results. This effort is an initial step in developing efficient whole building models that accurately incorporate the behavior of profiled steel panels as diaphragms

Thermally stimulated relaxation and behaviors of oxygen vacancies in SrTiO<inf>3</inf> single crystals with (100), (110) and (111) orientations

Abstract The strontium titanate (SrTiO3) single crystals with different orientations of (100), (110) and (111) were investigated using thermally stimulated depolarization current (TSDC) measurements, which has been proved to be an effective strategy to fundamentally study the relationship between relaxation phenomena and defect chemistry in dielectrics. The origins of different relaxations in SrTiO3 crystals were identified and the activation energy of oxygen vacancies was estimated from TSDC measurements. It was further found that oxygen-treated SrTiO3 crystals exhibit different relaxation behaviors. Noticeable changes of thermal relaxation associated with oxygen vacancies have taken place in relation to the crystalline anisotropy. The SrTiO3 (110) samples display higher concentration and activation energy of oxygen vacancies. First-principles calculations were carried out on SrTiO3 (110) crystals to study the effect of oxygen vacancy on different surface microstructure. From the resulting minimum formation energy of 0.63 eV, it demonstrates that the oxygen vacancies tend to form on the TiO-terminated surfaces. Considering the band structure, oxygen vacancies near the surface contribute to the transition of crystal from insulator to metallic characteristic.</jats:p

A comparison of the local spiral structure from Gaia DR2 and VLBI maser parallaxes

Context. The Gaia mission has released the second data set (Gaia DR2), which contains parallaxes and proper motions for a large number of massive, young stars. Aims. We investigate the spiral structure in the solar neighborhood revealed by Gaia DR2 and compare it with that depicted by VLBI maser parallaxes. Methods. We examined three samples with different constraints on parallax uncertainty and distance errors and stellar spectral types: (1) all OB stars with parallax errors of less than 10%; (2) only O-type stars with 0.1 mas errors imposed and with parallax distance errors of less than 0.2 kpc; and (3) only O-type stars with 0.05 mas errors imposed and with parallax distance errors of less than 0.3 kpc. Results. In spite of the significant distance uncertainties for stars in DR2 beyond 1.4 kpc, the spiral structure in the solar neighborhood demonstrated by Gaia agrees well with that illustrated by VLBI maser results. The O-type stars available from DR2 extend the spiral arm models determined from VLBI maser parallaxes into the fourth Galactic quadrant, and suggest the existence of a new spur between the Local and Sagittarius arms.Comment: 4 pages, 3 figures, 1 table, accepted for publication in A&

Effect of current intensity on residual stress of Q345/2Cr13 dissimilar steel plates

Based on the software Visual-Environment, Finite element method (FEM) was performed on the dissimilar butt-joint between Q345 and 2Cr13 steel aiming at the welding residual stress. The main contents in the paper were different current intensity was applied to modeling the welding process of Q345/2Cr13 dissimilar steel and the law of residual stress field were discussed. Based on the result, different current intensities have little effect on the lateral residual stress, while the longitudinal residual stress and the initial and end of the weld have a great influence. The physical properties of the dissimilar plates lead to uneven distribution of residual stress, and the current intensity should be smaller

Effect of hypoxia-inducible factor 1-alpha (HIF-1α) on proliferation and apoptosis of adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma cells

To understand whether hypoxia-inducible factor 1-alpha (HIF-1α) could protect AtT-20 cells from hypoxia induced apoptosis, we investigated the effects of HIF-1α on proliferation and apoptosis of adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma cells (AtT-20 cells). AtT-20 cells were treated with various concentrations of CoCl2 to induce hypoxia. 3-(4,5-Dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide, a yellow tetrazole (MTT) was applied to detect the proliferation of these cells. Western blot assay and real time polymerase chain reaction (PCR) were used to determine the protein and mRNA expressions of HIF-1α, respectively. In addition, AtT-20 cells were transfected with siRNA targeting HIF-1α and treated with different concentrations of CoCl2. The transfection efficacy was assessed by real-time PCR and western blot assay. Apoptosis was measured by fluorescein isothiocyanate (FITC)-annexin V/ propidium iodide (PI) staining and TUNEL staining. The effect of CoCl2 on the proliferation of AtT-20 cells was in a concentration and time dependent manner. When the concentration of CoCl2 was ≤100 μM and/or duration of CoCl2 treatment was ≤48 h, CoCl2 triggered the proliferation of AtT-20 cells. Nevertheless, the apoptosis rate of cells transfected with HIF-1α-siRNA was markedly increased after CoCl2 treatment. These findings suggest that, HIF-1α can promote the proliferation of AtT-20 cells and exert anti-apoptotic effect under hypoxic condition.Key words: Hypoxia inducible factor–1α, cobalt chloride, apoptosis, pituitary adenom

Effect of preheating temperature on post-weld residual stress of dissimilar steel plates

Based on the numerical simulation software Visual-Environment, the numerical calculation and analysis of residual stress field under different preheating temperatures for Q345/2Cr13 dissimilar plate welding were carried out in this paper. The effects of different preheating temperatures on post-weld residual stress were mainly studied. The results showed that different preheating temperatures have little effect on the lateral residual stress, while the longitudinal residual stress and the initial and end of the weld have greater impacts. For residual stress difference between the two base metals should not be too high, the dissimilar plate welding should adopt a moderate preheating temperature

Appropriateness of antibiotic prescriptions in ambulatory care in China: a nationwide descriptive database study

BACKGROUND: Inappropriate antibiotic use greatly accelerates antimicrobial resistance. The appropriateness of antibiotic prescriptions is well evaluated, using big observational data, in some high-income countries, whereas the evidence of this appropriateness is scarce in China. We aimed to assess the appropriateness of antibiotic prescriptions in ambulatory care settings in China to inform future antimicrobial stewardship. METHODS: We used data from the Beijing Data Center for Rational Use of Drugs, which was a national database designed for monitoring rationality of drug use. 139 hospitals that uploaded diagnosis and prescription information were included from 28 provincial-level regions of mainland China. Outpatient prescriptions were classified as appropriate, potentially appropriate, inappropriate, or not linked to any diagnosis for antibiotic use by following a published classification scheme. Antibiotic prescription rates for various diagnosis categories and proportions of inappropriate antibiotic prescriptions for different subgroups were estimated. Antibiotic prescribing patterns and proportions of individual antibiotics prescribed for different diagnosis categories were analysed and reported. FINDINGS: Between Oct 1, 2014, and April 30, 2018, 18 848 864 (10·9%) of 172 704 117 outpatient visits ended with antibiotic prescriptions. For conditions for which antibiotic use was appropriate, potentially appropriate, and inappropriate, 42·2%, 30·6%, and 7·6% of visits were associated with antibiotic prescriptions, respectively. Of all 18 848 864 antibiotic prescriptions, 9 689 937 (51·4%) were inappropriate, 5 354 224 (28·4%) were potentially appropriate, 2 893 102 (15·3%) were appropriate, and 911 601 (4·8%) could not be linked to any diagnosis. A total of 23 266 494 individual antibiotics were prescribed, of which 18 620 086 (80·0%) were broad-spectrum and the top four most prescribed antibiotics were third-generation cephalosporins (5 056 058 [21·7%]), second-generation cephalosporins (3 823 410 [16·4%]), macrolides (3 554 348 [15·3%]), and fluoroquinolones (3 285 765 [14·1%]). INTERPRETATION: Inappropriate antibiotic prescribing was highly prevalent nationwide in China. Over half of the antibiotic prescriptions were inappropriate in secondary-level and tertiary-level hospitals, suggesting an urgent need for outpatient antibiotic stewardship aimed at optimising antibiotic prescribing to achieve the goals set in China's 2016 national action plan to contain antimicrobial resistance. FUNDING: The National Natural Science Foundation of China

Spitzer IRS Spectra of Optically Faint Infrared Sources with Weak Spectral Features

Spectra have been obtained with the low-resolution modules of the Infrared Spectrograph (IRS) on the Spitzer Space Telescope (Spitzer) for 58 sources having f$_{\nu}$(24 micron) > 0.75 mJy. Sources were chosen from a survey of 8.2 deg$^{2}$ within the NOAO Deep Wide-Field Survey region in Bootes (NDWFS) using the Multiband Imaging Photometer (MIPS) on the Spitzer Space Telescope. Most sources are optically very faint (I > 24mag). Redshifts have previously been determined for 34 sources, based primarily on the presence of a deep 9.7 micron silicate absorption feature, with a median z of 2.2. Spectra are presented for the remaining 24 sources for which we were previously unable to determine a confident redshift because the IRS spectra show no strong features. Optical photometry from the NDWFS and infrared photometry with MIPS and the Infrared Array Camera on the Spitzer Space Telescope (IRAC) are given, with K photometry from the Keck I telescope for some objects. The sources without strong spectral features have overall spectral energy distributions (SEDs) and distributions among optical and infrared fluxes which are similar to those for the sources with strong absorption features. Nine of the 24 sources are found to have feasible redshift determinations based on fits of a weak silicate absorption feature. Results confirm that the "1 mJy" population of 24 micron Spitzer sources which are optically faint is dominated by dusty sources with spectroscopic indicators of an obscured AGN rather than a starburst. There remain 14 of the 58 sources observed in Bootes for which no redshift could be estimated, and 5 of these sources are invisible at all optical wavelengths.Comment: Accepted by Ap

Understanding AGN-Host Connection in Partially Obscured Active Galactic Nuclei. Part I: The Nature of AGN+HII Composites

The goal of our serial papers is to examine the evolutionary connection between AGN and star formation in its host galaxy in the partially obscured AGNs (i.e., Seyfert 1.8 and 1.9 galaxies). Taking advantage of these galaxies, the properties of both components can be studied together by direct measurements. In this paper, we focus on the broad-line composite galaxies (composite AGNs) which are located between the theoretical and empirical separation lines in the [NII]/Ha vs. [OIII]/Hb diagram. These galaxies are searched for from the composite galaxies provided by the SDSS DR4 MPA/JHU catalogs. After re-analyze the spectra, we perform a fine classification for the 85 composite AGNs in terms of the BPT diagrams. All the objects located below the three theoretical separation lines are associated with a young stellar population (<1Gyrs), while either a young or old stellar population is identified in the individual multiply-classified object. The multiply-classified objects with a very old stellar population are located in the LINER region in the [OI]/Ha vs. [OIII]/Hb diagram. We then consider the connection between AGN and star formation to derive the key results. The Eddington ratio inferred from the broad Ha emission, the age of the stellar population of AGN's host as assessed by D_n(4000), and the line ratio [OI]/Ha are found to be related with each other. These relations strongly support the evolutionary scenario in which AGNs evolve from high L/L_Edd state with soft spectrum to low L/L_Edd state with hard spectrum as young stellar population ages and fades. The significant correlation between the line ratio [OI]/Ha and D_n(4000) leads us to suggest that the line ratio could be used to trace the age of stellar population in type I AGNs.Comment: 39 pages, 11 figures, 1 table, accepted by Ap