On the nature of the hard X-ray source IGR J2018+4043

We found a very likely counterpart to the recently discovered hard X-ray source IGR J2018+4043 in the multi-wavelength observations of the source field. The source, originally discovered in the 20-40 keV band, is now confidently detected also in the 40-80 keV band, with a flux of (1.4 +/- 0.4) x 10(-11) erg cm(-2) s(-1). A 5 ks Swift observation of the IGR J2018+4043 field revealed a hard point-like source with the observed 0.5-10 keV flux of 3.4(+0.7)(-0.8) x 10(-12) erg cm(-2) s(-1) (90% confidence level) at alpha = 20h18m38.55s, delta = +40d41m00.4s (with a 4.2" uncertainty). The combined Swift-INTEGRAL spectrum can be described by an absorbed power-law model with photon index gamma = 1.3 +/- 0.2 and N_H = 6.1(+3.2)(-2.2) x 10(22) cm(-2). In archival optical and infrared data we found a slightly extended and highly absorbed object at the Swift source position. There is also an extended VLA 1.4 GHz source peaked at a beam-width distance from the optical and X-ray positions. The observed morphology and multiwavelength spectra of IGR J2018+4043 are consistent with those expected for an obscured accreting object, i.e. an AGN or a Galactic X-ray binary. The identification suggests possible connection of IGR J2018+4043 to the bright gamma-ray source GEV J2020+4023 (3EG J2020+4017) detected by COS B and CGRO EGRET in the gamma-Cygni SNR field.Comment: 5 pages, 3 figures, uses emulateapj styl

Thickness characterization toolbox for transparent protective coatings on polymer substrates

The thickness characterization of transparent protective coatings on functional, transparent materials is often problematic. In this paper, a toolbox to determine the thicknesses of a transparent coating on functional window films is presented. The toolbox consists of a combination of secondary ion mass spectrometry and profilometry and can be transferred to other transparent polymeric materials. A coating was deposited on designed model samples, which were characterized with cross-sectional views in transmission and in scanning/transmission electron microscopy and ellipsometry. The toolbox was then used to assess the thicknesses of the protective coatings on the pilot-scale window films. This coating was synthesized using straightforward sol-gel alkoxide chemistry. The kinetics of the condensation are studied in order to obtain a precursor that allows fast drying and complete condensation after simple heat treatment. The shelf life of this precursor solution was investigated in order to verify its accordance to industrial requirements. Deposition was performed successfully at low temperatures below 100 °C, which makes deposition on polymeric foils possible. By using roll-to-roll coating, the findings of this paper are easily transferrable to industrial scale. The coating was tested for scratch resistance and adhesion. Values for the emissivity (ε) of the films were recorded to justify the use of the films obtained as infrared reflective window films. In this work, it is shown that the toolbox measures similar thicknesses to those measured by electron microscopy and can be used to set a required thickness for protective coatings

Propylene metathesis over molybdenum silicate microspheres with dispersed active sites

In this work, we demonstrate that amorphous and porous molybdenum silicate microspheres are highly active catalysts for heterogeneous propylene metathesis. Homogeneous molybdenum silicate microspheres and aluminum-doped molybdenum silicate microspheres were synthesized via a nonaqueous condensation of a hybrid molybdenum biphenyldicarboxylate-based precursor solution with (3-aminopropyl)triethoxysilane. The as-prepared hybrid metallosilicate products were calcined at 500 °C to obtain amorphous and porous molybdenum silicate and aluminum-doped molybdenum silicate microspheres with highly dispersed molybdate species inserted into the silicate matrix. These catalysts contain mainly highly dispersed MoOx species, which possess high catalytic activity in heterogeneous propylene metathesis to ethylene and butene. Compared to conventional silica-supported MoOx catalysts prepared via incipient wetness impregnation (MoIWI), the microspheres with low Mo content (1.5-3.6 wt %) exhibited nearly 2 orders of magnitude higher steady-state propylene metathesis rates at 200 °C, approaching site time yields of 0.11 s-1CF CryoE; European Regional Development Fund-Project “UP CIISB, (CZ.02.1.01/0.0/0.0/18_046/0015974, LM2018110); Francqui Foundation; Grant Agency of Masaryk University, (MUNI/A/1298/2022, MUNI/J/0007/2021); U.S. Department of Energy, USDOE; Basic Energy Sciences, BES, (DE-SC0016214); Massachusetts Institute of Technology, MIT; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT, (LM2023042, RP/CPS/2022/007); Grantová Agentura České Republiky, GA ČR, (GJ20-03636Y); Central European Institute of Technology, CEITECMinistry of Education, Youth, and Sports of the Czech Republic within the INTER-EXCELLENCE II program; Ministry of Education, Youth, and Sports of the Czech Republic [RP/CPS/2022/007]; U.S. Department of Energy, Office of Basic Energy Sciences [DE-SC0016214]; European Regional Development Fund-Project "UP CIISB" [CZ.02.1.01/0.0/0.0/18_046/0015974, LM2018110]; MEYS CR [GJ20-03636Y, LM2023042]; Czech Science Foundation; Grant Agency of Masaryk University [MUNI/J/0007/2021, MUNI/A/1298/2022]; Francqui Foundation for the Francqui Research Professor chai

The Sales Effect of Word of Mouth: A Model for Creative Goods and Estimates for Novels

Weekly sales of creative goods – like music records, movies or books – usually peak shortly after release and then decline quickly. In many cases, however, they follow a hump-shaped pattern where sales increase for some time. A popular explanation for this phenomenon is word of mouth among a population of heterogeneous buyers, but previous studies typically assume buyer homogeneity or neglect word of mouth altogether. In this paper, I study a model of new-product diffusion with heterogeneous buyers that allows for a quantification of the sales effect of word of mouth. The model includes Christmas sales as a special case. All parameters have an intuitive interpretation. Simulation results suggest that the parameters are estimable for data that are not too volatile and that cover a sufficiently large part of a title’s life cycle. I estimate the model for four exemplary novels using scanner data on weekly sales.Meistens erreichen die wöchentlichen Verkäufe von kreativen Produkten wie Musikalben, Kinofilmen oder Büchern kurz nach Veröffentlichung ihren Höhepunkt und nehmen dann schnell ab. In einigen Fällen jedoch zeigen sie einen buckelartigen Verlauf mit zunächst ansteigenden Verkäufen. Eine populäre Erklärung für dieses Phänomen beruht auf der Existenz von Mundpropaganda unter heterogenen Käufern, doch bisherige Studien gehen typischerweise von der Annahme homogener Käufer aus oder vernachlässigen Mundpropaganda gänzlich. Dieses Papier betrachtet ein Modell der Verbreitung neuer Produkte unter heterogenen Käufern, welches eine Quantifizierung der Verkaufswirkung von Mundpropaganda ermöglicht. Das Modell beinhaltet Weihnachtsverkäufe als Spezialfall. Alle Modellparameter haben eine intuitive Bedeutung. Ergebnisse einer Simulation zeigen, dass die Parameter empirisch geschätzt werden können, wenn die Daten einen hinreichend großen Teil des Verkaufszyklus eines Titels abdecken und nicht zu volatil sind. Das Modell wird auf Scannerdaten für vier exemplarische Romane angewendet

The binary nature of the Galactic centre X-ray source CXOGC J 174536.1-285638

Context. The combination of X-ray and near-IR surveys of the central 2° × 0.8° of the Galactic centre have revealed a population of X-ray bright massive stars. However, the nature of the X-ray emission, originating in wind collision zones or via accretion onto compact objects, is uncertain.Aims. In order to address this we investigated the nature of one of the most luminous X-ray sources - CXOGC J174536.1-285638 .Methods. This was accomplished by an analysis of the near-IR spectrum with a non-LTE model atmosphere code to determine the physical parameters of the primary.Results. This was found to be an highly luminous WN9h star, which is remarkably similar to the most massive stars found in the Arches cluster, for which comparison to evolutionary tracks suggest an age of 2–2.5 Myr and an initial mass of ~110 Mʘ. The X-ray properties of CXOGC J174536.1-285638 also resemble those of 3 of the 4 X-ray detected WN9h stars within the Arches and in turn other very massive WNLh colliding wind binaries, of which WR25 forms an almost identical “twin”. Simple analytical arguments demonstrate consistency between the X-ray emission and a putative WN9h+mid O V-III binary, causing us to favour such a scenario over an accreting binary. However, we may not exclude a high mass X-ray binary interpretation, which, if correct, would provide a unique insight into the (post-SN) evolution of extremely massive stars. Irrespective of the nature of the secondary, CXOGC J174536.1-285638 adds to the growing list of known and candidate WNLh binaries. Of the subset of WNLh stars subject to a radial velocity survey, we find a lower limit to the binary fraction of ~45%; of interest for studies of massive stellar formation, given that they currently possess the highest dynamically determined masses of any type of star

Effects of adaptation to sea water, 170% sea water and to fresh water on activities and subcellular distribution of branchial Na + −K + -ATPase, low- and high affinity Ca ++ -ATPase, and ouabain-insensitive ATPase in Gillichthys mirabilis

1. Branchial activities of Na + −K + -ATPase, ouabain-insensitive ATPase, (Mg ++ -ATPase) and Ca ++ -ATPase were measured in Gillichthys mirabilis after adaptation to salinities ranging from 170% SW to FW. Stabilities of these activities against freezing and deoxycholate solubilization and the temperature-dependence of activity rates were also investigated. Subcellular distribution and some kinetic properties of these activities, and of SDH were compared in branchial tissues of fish adapted to 170% SW and to FW.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47126/1/360_2004_Article_BF00782593.pd

Aerosol Routes to Nano-structured Heterogeneous Catalysts

The technical features of aerosol processes make them highly interesting for the continuous, large scale, and tailored production of divided nanomaterials, and in particular of advanced heterogeneous (nano)catalysts.1 In addition to the “simple” aggregation of preformed particles via spray drying, reactive aerosol processes – such as the “aerosol-assisted sol-gel” process (AASG) – allow synthesizing tailored-made catalysts with tunable surface properties, textures, compositions, surface functionalities, etc.2 The method is based on the sol-gel chemistry process, possibly coupled with the evaporation-induced self-assembly (EISA) concept.3 It allows producing micronic or submicronic, inorganic or hybrid organic-inorganic particles bearing tunable and calibrated porous structures at different scales. Here, we explain why this peculiar mode of preparation has led to high-performance solid nano-catalysts in various applications including olefin metathesis,4-6 lactate synthesis,7-10 olefin epoxidation,11 (trans)-esterification.12, 13 We will also demonstrate the concept of chemo-enzymatic heterogeneous catalysts able to run cascade reactions.14, 15 Our objective is to demonstrate the tremendous possibilities offered by the coupling between bottom up sol-gel routes and aerosol processing technologies, which will arguably represent a major route of innovation not only in the field of catalyst preparation, but also more broadly in the mushrooming nanotechnology field

MoO3-based heterogeneous catalysts for the metathesis of propene

The heterogeneous metathesis of light olefins is a crucial reaction for the regulation of olefins stocks at low energy cost. Molybdenum oxide dispersed at the surface of an inorganic support is a regarded cheap and robust heterogeneous metathesis catalyst. This thesis presents fundamental and applied approaches to the understanding of the active species and to the development of new efficient catalytic materials. A systematic investigation of MoO3/SiO2-(Al2O3) catalysts with variable support composition describes the crucial role of Al. Then, the best support composition is selected and a classical wet impregnation preparation method is inspected in details. For these catalysts, the genesis of active and inactive species during the preparation is described in link with the (limited) performances reached. Alternative MoO3 deposition modes are then explored. Firstly, the wet impregnation with alternative Mo precursors (use of oxalic acid additive or use of molybdenum oxide hydrates solutions) allows impeding the formation of inactive Mo species upon calcination and produces more active catalysts. Secondly, the direct thermal spreading of MoO3 onto the support is identified as an alternative straightforward route to obtain active metathesis catalysts. An innovative non-hydrolytic sol-gel method is then implemented to prepare MoO3-SiO2-Al2O3 mixed oxides. Upon optimization of homogeneity, texture and composition, these samples turn out to be very active metathesis catalysts because highly dispersed molybdate species are stabilized at their surface.(AGRO 3) -- UCL, 201

Approches sol-gel pour la préparation de catalyseurs hétérogènes nanostructurés, hybrides et chémo-enzymatiques

Le développement de catalyseurs hétérogènes innovants est une des clés permettant d’envisager la mise en place de procédés chimiques plus efficaces et plus verts. Cet article présente les potentialités de deux approches de synthèse de matériaux catalytiques basées sur la chimie sol-gel. Par une stratégie de synthèse « brique par brique », les spécificités du sol-gel non hydrolytique et du sol-gel assisté par aérosol permettent de maîtriser les paramètres physico-chimiques clés qui dictent les performances des catalyseurs : texture, structure, composition, polarité de surface, dispersion de la phase active, hybridation avec des fonctions organiques ou des enzymes. Ceci est illustré pour une série d’applications, incluant la déshydratation d’alcools, l’hydrogénation du CO2, la valorisation de composés biosourcés, l’oxydation sélective d’alcènes, etc

PREPARATION OF POROUS CATALYSTS BY AEROSOL-ASSISTED SOL-GEL

The technical features of aerosol processes make them alluring for the continuous, large scale, and tailored production of divided nanomaterials, and in particular of advanced heterogeneous (nano)catalysts. Aside from the common aggregation of preformed particles via spray drying, reactive aerosol processes allow synthesizing tailored-made catalysts with tunable surface properties, textures, compositions, surface functionalities, etc. In the “aerosol-assisted sol-gel” process (AASG), the inorganic polycondensation reactions are confined in small droplets and happen in seconds. In addition, sol-gel reactions can be coupled with the evaporation-induced self-assembly (EISA) concept. This allows producing micronic or submicronic, inorganic or hybrid organic-inorganic particles bearing tunable and calibrated porous structures at different scales. Here, we explain why this peculiar mode of preparation has led to high-performance solid nano-catalysts in various applications including olefin metathesis, lactate synthesis, olefin epoxidation, (trans)-esterification, and dehydrogenation. In particular, we show how the method offers an excellent control over homogeneity, dispersion, surface functionalities, and texture. We will also demonstrate the concept of chemo-enzymatic heterogeneous catalysts obtained via spray techniques. Our objective is to demonstrate the tremendous possibilities offered by the coupling between bottom up sol-gel routes and aerosol processing technologies, which will arguably represent a major route of innovation not only in the field of catalyst preparation, but also more broadly in the mushrooming nanotechnology field