In its Sixth Edition, this book has been updated and revised to incorporate new information on technology, economic, and political issues that have impacted the use of fluids to drill and complete ...oil and gas wells. With updated content on completion fluids and reservoir drilling fluids; health, safety and environment; drilling fluid systems and products; new fluid systems and additives from both chemical and engineering perspectives; wellbore stability, adding the new R&D on water-based muds; and equipment and procedures for evaluating drilling fluid performance in light of the advent of digital technology and better manufacturing techniques, this book has been thoroughly updated to meet the drilling and completion engineer's needs.
The CAMS New Zealand meteor shower survey detected a brief outburst of delta Pavonids (IAU shower 120, code DPA) with a compact radiant on March 31, 2019. This is the first instrumental detection of ...a shower long suspected to exist by visual observers monitoring the theoretical radiant of parent comet C/1907 G1 (Grigg-Mellish), despite it being listed in comet catalogs only with a parabolic orbit. The 2019 detection of an associated meteor shower confirms that this comet moves in an elliptical orbit. The range of allowed orbit solutions fitted to the 1907 observations of the comet strongly correlate node and semi-major axis. Taking into account the difference in node between comet orbit and dust trail, the time of the outburst constrains the comet orbital period to 447 ± 80 years (heliocentric), having last been near the sun in A. D. 1460 ± 80 years. The corresponding elliptical orbital elements for C/1907 G1 are presented. The short 23-min duration of the outburst (FWHM = 16 min) confirms that C/1907 G1 is a small comet, having ejected dust with low ejection speeds. It passed close enough to Earth orbit to be a potentially hazardous comet in future returns.
•An outburst of meteors on March 31, 2019, shows that parent comet Grigg-Mellish moves in an elliptical orbit and was near the Sun before.•The timing of the outburst, combined with the observations of the comet in 1907, constrains the comet orbital period.•The timing of the outburst, combined with the observations of the comet in 1907, constrains the comet orbital period.•The comet ejected the meteoroids when it was near the Sun in A. D. 1460 ± 80 y.•Because the comet will return, and has a small miss-distance, it is a potential impact hazard to Earth.
In the present study, we used an integrative taxonomy approach to redescribe a population of Echiniscus quadrispinosus quadrispinosus Richters, 1902 from the neotype locality in the Taunus Mountain ...Range (Germany). We found clear differences in the chaetotaxy formula between the life stages of E. q. quadrispinosus. The body appendages B are, in general, absent in juveniles. Moreover, in larvae all body lateral appendages, except for E, are absent. We also obtained DNA sequences of 18S rRNA, 28S rRNA, ITS-2, and COI of E. q. quadrispinosus from the neotype locality and three Norwegian populations. Comparison with the sequences available in GenBank showed low genetic differences between the neotypic population and specimens from other localities. Therefore, we decided to establish our specimens from Taunus Mountain Range as neotype and paraneotypes of E. q. quadrispinosus. We also discussed and amended the taxonomic status of three subspecies E. q. brachyspinosus Bartoš, 1934, E. q. cribrosus Murray, 1907 and E. q. fissispinosus Murray, 1907 and established them as junior synonyms of E. q. quadrispinosus. Finally, we also confirmed E. lichenorum Maucci, 1983 as a valid species, clearly different from E. q. quadrispinosus.
ABSTRACT
We report X-ray observations of the high mass X-ray binary (HMXB) pulsar 4U 1907+09. Spectral and timing analysis of the source has been performed using Nuclear Spectroscopic Telescope Array ...(NuSTAR) observation. Timing analysis of the photon events revealed the coherent X-ray pulsation of the source with a pulse period of 442.92 ± 0.03 s. It is observed that the source is spinning down at a rate of 0.1971(4) s yr−1. The pulse profile is characterized by a decaying amplitude of the secondary peak and relative growth in the amplitude of the primary peak with an increase in energy. The broad-band spectral coverage of NuSTAR has been used to observe multiple absorption features in the X-ray continuum of the source. We confirm the presence of two prominent cyclotron absorption features at ∼17 and ∼38 keV, respectively. In addition, we have detected an absorption-line feature at ∼8 keV, with an equivalent width of ∼1.3 keV. The variation of the spectral parameters with pulse phase has been observed using phase-resolved spectroscopy and the relevant variabilities of the parameters have been discussed with the underlying physical implications. The continuum evolution and variations in spectral parameters have also been studied by time-resolved spectroscopy.
During the Progressive Era (1900–29), economic growth was rapid but volatile. Boom and busts witnessed the formation and failure of tens of thousands of firms and thousands of banks. This essay uses ...new data and methods to identify causal links between failures of banks and bankruptcies of firms. Our analysis indicates that bank failures triggered bankruptcies of firms that depended upon banks for ongoing access to commercial credit. Firms that did not depend upon banks for credit did not fail in appreciably larger numbers after banks failed.
Wind-fed supergiant X-ray binaries are precious laboratories not only to study accretion under extreme gravity and magnetic field conditions, but also to probe the still highly debated properties of ...massive star winds. These include clumps, originating from the inherent instability of line driven winds, and larger structures. In this paper we report on the results of the last (and not yet published) monitoring campaigns that our group has been carrying out since 2007 with both
XMM-Newton
and the
Swift
Neil Gehrels observatory. Data collected with the EPIC cameras on board
XMM-Newton
allow us to carry out a detailed hardness-ratio-resolved spectral analysis that can be used as an efficient way to detect spectral variations associated with the presence of clumps. Long-term observations with the XRT on board
Swift
, evenly sampling the X-ray emission of supergiant X-ray binaries over many different orbital cycles, are exploited to look for the presence of large-scale structures in the medium surrounding the compact objects. These can be associated either with corotating interaction regions or with accretion and/or photoionization wakes, and with tidal streams. The results reported in this paper represent the outcomes of the concluded observational campaigns we carried out on the supergiant X-ray binaries 4U 1907+09, IGR J16393−4643, IGR J19140+0951, and XTE J1855−026, and on the supergiant fast X-ray transients IGR J17503−2636, IGR J18410−0535, and IGR J11215−5952. All results are discussed in the context of wind-fed supergiant X-ray binaries and ideally serve to optimally shape the next observational campaigns aimed at sources in the same classes. We show in one of the Appendices that IGR J17315−3221, preliminarily classified in the literature as a possible supergiant X-ray binary discovered by INTEGRAL, is the product of a data analysis artifact and should thus be disregarded for future studies.
Western part of Zagreb is delineated by the Street of the Republic of Austria on the east side, Ilica Street in the north, the railway line in the south and the Črnomerec stream in the west. It was ...enclosed into a masterplan for the first time in the Regulatory Plan from 1887 and envisaged as the extension of the Lower Town to the west. In the first Regulatory Plan of Zagreb from 1865, only the square in front of the railway station was located there, while the rest was not encompassed. Since the opening of the first railway station in 1862, industrial plants have been randomly built into the western part of the city. In 1878 the City Waterworks were put into operation and at that occasion the first Waterworks Road (Vodovodna cesta) was staked out, connecting Ilica, the historical roadway in the north (since the 15th century), with the City Waterworks. In Milan Lenuci’s Regulatory Plan from 1907 the western part of the city retained its layout. The only urban planning since the end of the 19th century until the First World War in the western part of Zagreb was implemented with the aim of connecting six army barrack complexes.
In late nineteenth-century France, church bells were an integral part of society, sounding the quotidian rhythms of life. During WWI, a shortage of metals for the war effort resulted in German ...authorities requisitioning church bells in Germany and occupied territories. While the sequestration of the only bell from the church L'Eglise Sainte-Geneviève in the village of Marquillies (France) occurred under this guise, this was an invented cover story in order to remove the bell as a war trophy to Berlin. Contravening the revised Hague Convention of 1907, the removal the bell occurred because, owing to texts inscribed onto the bell by both parties, it was a propaganda tool by the French community and German forces alike. As a unique political symbol of the tension in the Alsace-Lorraine region in the early twentieth-century, the bell serves as a case highlighting the political power of a communal religious icon.
