964 research outputs found
Investigation of the reactivity of AlCl3 and CoCl2 toward molten alkali-metal nitrates in order to synthesize CoAl2O4
No full textCobalt aluminate CoAl2O4 powder, constituted of nano-sized crystallites, is prepared, involving the reactivity of AlCl3 and CoCl2 with molten alkali-metal nitrates. The reaction at 450 °C for 2 h leads to a mixture of spinel oxide Co3O4 and amorphous γ-Al2O3. It is transformed into the spinel oxide CoAl2O4 by heating at 1000 °C. The powders are mainly characterized by XRD, FTIR, ICP, electron microscopy and diffraction, X-EDS and diffuse reflection. Their properties are compared to those of powders obtained by solid state reactions of a mechanical mixture of chlorides or oxides submitted to the same thermal treatment
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High-resolution Near-infrared Spectroscopy of a Flare around the Ultracool Dwarf vB 10
No full textWe present high-resolution observations of a flaring event in the M8 dwarf vB 10 using the near-infrared Habitable-zone Planet Finder (HPF) spectrograph on the Hobby-Eberly Telescope. The high stability of HPF enables us to accurately subtract a vB 10 quiescent spectrum from the flare spectrum to isolate the flare contributions and study the changes in the relative energy of the Ca ii infrared triplet, several Paschen lines, the He λ10830 triplet lines, and to select iron and magnesium lines in HPF's bandpass. Our analysis reveals the presence of a red asymmetry in the He λ10830 triplet, which is similar to signatures of coronal rain in the Sun. Photometry of the flare derived from an acquisition camera before spectroscopic observations and the ability to extract spectra from up-the-ramp observations with the HPF infrared detector enable us to perform time-series analysis of part of the flare and provide coarse constraints on the energy and frequency of such flares. We compare this flare with historical observations of flares around vB 10 and other ultracool M dwarfs and attempt to place limits on flare-induced atmospheric mass loss for hypothetical planets around vB 10. © 2022. The Author(s). Published by the American Astronomical Society.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Leucophenga pentapunctata Panigrahy & Gupta 1982
No full textLeucophenga pentapunctata Panigrahy & Gupta, 1982 (Figs 2 G, 6 E–H, 10 G, 10 H, 14 A, 14 B, 23) Leucophenga pentapunctata Panigrahy & Gupta, 1982: 487. Diagnosis. Wing with 5 patches distinctly (Fig. 2 G); all femora with a brownish patch subbasally; hypandrium with a bunch of long pubescence submedially (Fig. 23 B); aedeagus thick, with pubescence distoventrally (Fig. 23 D). Description. Ocellar triangle brownish yellow, with 3–6 setae above ocellar setae. Frons brownish to yellowish brown. Pedicel yellowish brown; first flagellomere brownish and brown at tip. Clypeus yellowish brown medially and dark brown laterally. Palpus mostly brownish to brown, slightly larger distally in female than in male. Mesonotum brownish yellow to yellowish brown, sometimes with brown longitudinal stripes sublaterally (Fig. 6 E, F). Postpronotal lobe yellow (Fig. 6 G, H). Acrostichal setulae in 10–12 irregular rows (Fig. 6 E, F). Scutellum brown, dark brown laterally and pale at tip (Fig. 6 E, F). Pleura with a brownish to brown, longitudinal stripe above (Fig. 6 G, H). Katepisternum yellow, brown above; mesopleuron yellow, with a brown patch (Fig. 6 G, H). Wing (Fig. 2 G): Costal vein between R 2 + 3 and R 4 + 5 distally with 6–8 peg-like spinules on ventral surface. Abdominal tergites dark brown, with yellow patches (Fig. 10 G, H). Male terminalia: Epandrium nearly entirely pubescent, with 12 setae near posterior margin and ventral corner per side (Fig. 23 A). Paramere broadened, round apically, lacking pubescence, with 6 sensilla mediodorsally and 1 sensillum apically (Fig. 23 C). Measurements. BL = 3.20–4.47 mm in ♂, 3.60–4.20 mm in ♀ (range in 5 ♂ and 5 ♀), THL = 1.67–2.47 mm in ♂, 1.77–2.13 mm in ♀, WL = 2.77–4.07 mm in ♂, 3.23–3.83 mm in ♀, WW = 1.27–1.73 mm in ♂, 1.50–1.78 mm in ♀, arb = 8–12 / 4–6, avd = 0.76–0.97, adf = 1.76–2.21, flw = 1.65–2.20, FW/HW = 0.33–0.39, ch/o = 0.03–0.05, prorb = 0.53–0.76, rcorb = 0.56–0.80, vb = 0.35–0.50, dcl = 0.40–0.56, presctl = 0.50–0.69, sctl = 1.22–1.36, sterno = 0.72–0.82, orbito = 1.83–2.42, dcp = 0.17–0.27, sctlp = 1.00– 1.39, C = 1.57–2.33, 4 c = 1.32–1.75, 4 v = 1.69–2.09, 5 x = 1.09–1.47, ac = 3.05–4.31, M = 0.54–0.64, C 3 F = 0.84–0.93. Specimens examined. CHINA: 1 ♂, 1 ♀ (SCAU, Nos 123093, 94), Diaoluoshan, Lingshui, Hainan, 18 ° 10 'N, 108 ° 52 'E, 1000m, 3.xii. 2003, ex tussocks, HW Chen; 1 ♀ (SCAU, No. 123095), Hesong, Menghai, Yunnan, 1900m, 9.iv. 2011, ex tree trunk, ZF Shao; 6 ♂, 1 ♀ (SCAU, Nos 123096 – 123102), Menglun, Mengla, Yunnan, 900m, 19.iv. 2007, ex tree trunks, HW Chen; 2 ♀ (SCAU, Nos 123103, 04), Wangtianshu, Mengla, Yunnan, 600m, 30.ix. 2011, ex tree trunks, HW Chen; 1 ♂, 4 ♀ (SCAU, Nos 123105 –09), Yixiang, Puer, Yunnan, 27 ° 12 'N, 100 °03'E, 1400m, 13.v. 2012, ex tree trunks, HW Chen; 1 ♀ (SCAU, No. 123300), Yixiang, Puer, Yunnan, 1400m, 18.x. 2012, ex tree trunk, JJ Gao; 1 ♂, 1 ♀ (SCAU, Nos 123110, 11), Beibeng, Motuo, Xizang, 29 ° 14 'N, 95 ° 10 'E, 780m, 28.ix. 2010, ex tree trunks, JJ Gao. Distribution. China (Hainan, Yunnan, Xizang), India (Orissa).Published as part of Huang, Jia, Li, Tong & Chen, Hongwei, 2014, The genus Leucophenga (Diptera, Drosophilidae), part IV: the ornata species group from the East Asia, with morphological and molecular evidence (II), pp. 1-55 in Zootaxa 3893 (1) on pages 30-31, DOI: 10.11646/zootaxa.3893.1.1, http://zenodo.org/record/28753
Fibre-reinforced composites: Their fabrication, properties and applications
No full text327-340An attempt has been made to describe the wide range of composites based on the combination of reinforcing fibres likecarbon, aramids, high-modulus polyethylene, ceramic, boron and glass with matrices like thermosetting resins, thermoplasticpolymers, soft metals, ceramics and carbon. Starting with the definition and classification of composites, the advantagesof the fibrous shape and of an optimum adhesion between the fibre and the matrix are considered. This is followed byan account of the properties of the constituents of the composites, viz. the fibres and the matrices. The composite fabricationprocesses are then described. Finally, the properties and major applications of the composites are briefly discussed
Decrease of pre-load in high strength bolts in the coarse of time (provisional result)
No full textCivil Engineering and GeosciencesStructural Engineerin
The programme of a series of tests in order to compare the friction factors of Fe 37 and Fe 52
No full textCivil Engineering and GeosciencesStructural Engineerin
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