142,942 research outputs found
Acoustic radiation due to scattering of T-S wave by the mean-flow distortion induced by steady local suction
No full textSubstantial sound waves can be generated by boundary-layer instability modes when the latter are scattered by a rapid mean-flow distortion. This is a rather generic mechanism and operates when an oncoming T-S wave is scattered by a steady local suction slot. This paper focuses on this problem by extending a recently developed Local Scattering Theory (Wu & Dong, J. Fluid Mech. submitted), where a so-called transmission coefficient, defined as the ratio of the T-S wave amplitude downstream of the scatter to that upstream, is introduced to characterize the effect of a local scatter on boundary-layer instability and transition. As in the earlier work, the mathematical formulation is based on triple-deck formulism, but in order to accommodate the acoustic far field, which was not considered in the paper mentioned, the unsteady terms in the upper deck, which play a leading-order role in radiation, are retained, and the influence of the radiated sound on the near-wall perturbation is included. The upper deck equation for the pressure is the Helmholtz equation rather than the Laplace equation. This leads to a modified pressure-displacement relation, which is coupled with the linearized boundary-layer equations in the lower deck. Discretization of the whole system formulates a generalized eigenvalue problem, which is solved numerically. It is found that suction suppresses oncoming T-S waves, and this effect increases with the suction velocity and the slot width. The directivity is ndependent of the flow parameters only when the Mach number is low. The intensity of the radiated sound in general increases with the frequency, the suction velocity and the width of the suction slot. Interestingly, for O(1) suction velocities, the radiated sound is very weak, indicating that the gain of stabilizing effect does not cause aeroacoustic penalty
ProvStore: a public provenance repository
No full textProvStore is the first online public provenance repository supporting the new PROV standards by W3C. It allows users and applications to store and (optionally) publish the provenance of their data on the Web. Provenance documents can be transformed, visualized, and shared in various serializations, with all the functionality also available to automated applications via a RESTful API (OAuth supported)
Tectaria wigmanii S. Y. Dong 2014
No full textTectaria wigmanii (Racib.) S.Y. Dong (2014: 227). Basionym:— Aspidium wigmanii Raciborski (1902: 61). = Dryopteris wigmanii (Racib.) Christensen (1905: 301); Heterogonium wigmanii (Racib.) Holttum (1955: 271). Type:— INDONESIA. Java: Bogor, Cult. Hort. Bot. 2K.XI.13 (lectotype, BO, designated by Holttum 1975: 216, not seen; isolectotype, L-0051702!), original from Aru Islands, Indonesia. Other synonym:— Dryopteris sagenioides var. gurupahensis Christensen (1922: 95). = Dryopteris gurupahensis (C. Chr.) Christensen (1934: 45); Heterogonium gurupahense (C. Chr.) Holttum (1955: 272). Type:— INDONESIA. North Sulawesi (formerly Celebes): Gurupahi, Bolaang-Mongondou, in primary forest, 600 m, 7 April 1917, W. Kaudern 18 (lectotype, designated here, S-P-10859!; isolectotype, BM-001048664!). When publishing Dryopteris sagenioides var. gurupahensis, Christensen (1922: 95) cited two numbers of Kaudern’s collections, 17 and 18, as the type; these two are syntypes according to Art. 9.6 of the ICN (Turland & al. 2018). The syntype Kaudern 18 kept in S (barcode S-P-10859) is here designated as the lectotype. As the type of this taxon agrees with the type of T. wigmanii (then named Heterogonium wigmanii), Holttum (1975) treated them as representatives of a single species. As mentioned by Holttum (1975), T. wigmanii is morphologically very similar to T. sagenioides but differs by the larger size of fronds, which are up to 50–75 (versus 30–40) cm long. The two species are thought to have different distribution, namely, T. wigmanii is confined to Sulawesi and Maluku, Indonesia, whereas T. sagenioides occurs in Philippines, West Malesia, and northwards to Indochina and Hainan Island (Holttum 1975, 1991). So Heterogonium gurupahense recorded in Thailand (Tagawa & Iwatsuki 1988) and in Vietnam (Phan 2010) should be corrected to be T. sagenioides. It seems to me that there is no significant difference between T. wigmanii and T. sagenioides besides the larger frond size and the clear dimorphism (fertile fronds obviously contracted) in T. wigmanii. Further studies, especially chromosome counting and molecular phylogenetic analyses, are needed to confirm the taxonomic identity of T. wigmanii.Published as part of Dong, Shi-Yong, 2022, The new combination Tectaria colaniae and notes on the synonymy and distribution of Tectaria wigmanii (Tectariaceae), pp. 245-248 in Phytotaxa 566 (2) on page 247, DOI: 10.11646/phytotaxa.566.2.10, http://zenodo.org/record/711907
Letter, [Author unclear] to Paulina T. Merritt
No full textHandwritten letter to Paulina Merritt from an unknown author, October 1, 1876.
Low noise high performance 50nm T-gate metamorphic HEMT with cut-off frequency f<sub>T</sub> of 440 GHz for millimeterwave imaging receivers applications
Get PDFThe 50 nm m-HEMT exhibits extremely high f<sub>T</sub>, of 440GHz, low F<sub>min</sub> of 0.7 dB, associated gain of 13 dB at 26 GHz with an exceptionally high Id of 200 mA/mm and gm of 950 ms/mm at low noise biased point
The GPS Data Collection and Transmission Strategy for Floating Vehicle Technology
No full textFloating vehicle equipped floating vehicle technology has been widely used to collect urban and inter-urban road network traffic data for network evaluation, traffic management and dynamic road guidance purposes. It has become one of the major technologies of Intelligent Transport Systems (ITS). Most of the commonly used floating vehicle devices receive floating vehicle data in a frequency of 1 Hz. To collect real time traffic data of the road network for the above application, floating vehicle data from floating vehicles has to be transmitted from vehicles to a traffic data management centre in short time intervals. With the increase in the numbers of floating vehicles, the cost on communication increases dramatically. This is often one of the major barriers limiting the application of floating vehicle technologies for real time traffic route guidance and many other applications. This paper proposes a floating vehicle - floating vehicle data transmission strategy, which can significantly reduce the data transmission cost with satisfied accuracy for real time traffic management and dynamic road guidance purposes
Tectaria multicaudata var. amplissima S. Y. Dong 2013, comb. nov.
No full textTectaria multicaudata var. amplissima (Holttum) S.Y.Dong, comb. nov. Basionym:— Tectaria griffithii var. amplissima Holttum (1991b: 551). Type:— INDONESIA. Sumatra: Padang Panjang (Bukit Tilabung), 9 January 1913, Matthew s.n. (holotype K!). Note:—As Holttum (1991a, b) has pointed out, T. multicaudata var. amplissima has rather finely dissected fronds with as many as six pairs of pinnules on the basal pinnae. In contrast, the fronds are not so dissected with only one or rarely two pinnules on basal pinna in T. multicaudata var. multicaudata.Published as part of Ding, Hui-Hui, Chao, Yi-Shan & Dong, Shi-Yong, 2013, Taxonomic novelties in the fern genus Tectaria (Tectariaceae), pp. 61-64 in Phytotaxa 122 (1) on page 63, DOI: 10.11646/phytotaxa.122.1.3, http://zenodo.org/record/508493
Handwritten biographical information on Paulina T. McClung Merritt
No full textA handwritten biography of Paulina T. McClung Merritt by an unknown author, 1892.
Heterogeneous and tissue-specific regulation of effector T cell responses by IFN-gamma during Plasmodium berghei ANKA infection.
Get PDFIFN-γ and T cells are both required for the development of experimental cerebral malaria during Plasmodium berghei ANKA infection. Surprisingly, however, the role of IFN-γ in shaping the effector CD4(+) and CD8(+) T cell response during this infection has not been examined in detail. To address this, we have compared the effector T cell responses in wild-type and IFN-γ(-/-) mice during P. berghei ANKA infection. The expansion of splenic CD4(+) and CD8(+) T cells during P. berghei ANKA infection was unaffected by the absence of IFN-γ, but the contraction phase of the T cell response was significantly attenuated. Splenic T cell activation and effector function were essentially normal in IFN-γ(-/-) mice; however, the migration to, and accumulation of, effector CD4(+) and CD8(+) T cells in the lung, liver, and brain was altered in IFN-γ(-/-) mice. Interestingly, activation and accumulation of T cells in various nonlymphoid organs was differently affected by lack of IFN-γ, suggesting that IFN-γ influences T cell effector function to varying levels in different anatomical locations. Importantly, control of splenic T cell numbers during P. berghei ANKA infection depended on active IFN-γ-dependent environmental signals--leading to T cell apoptosis--rather than upon intrinsic alterations in T cell programming. To our knowledge, this is the first study to fully investigate the role of IFN-γ in modulating T cell function during P. berghei ANKA infection and reveals that IFN-γ is required for efficient contraction of the pool of activated T cells
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