We investigate the long-term optical-infrared variability of SV Cep, and explain it in the context of an existing UX Ori (UXOR) model. A 25-month monitoring programme was completed with the Infrared ...Space Observatory in the 3.3-100 um wavelength range. Following a careful data reduction, the infrared light curves were correlated with the variations of SV Cep in the V-band. A remarkable correlation was found between the optical and the far-infrared light curves. In the mid-infrared regime the amplitude of variations is lower, with a hint for a weak anti-correlation with the optical changes. In order to interpret the observations, we modelled the spectral energy distribution of SV Cep assuming a self-shadowed disc with a puffed-up inner rim, using a 2-dimensional radiative transfer code. We found that modifying the height of the inner rim, the wavelength-dependence of the long-term optical-infrared variations is well reproduced, except the mid-infrared domain. The origin of variation of the rim height might be fluctuation in the accretion rate in the outer disc. In order to model the mid-infrared behaviour we tested to add an optically thin envelope to the system, but this model failed to explain the far-infrared variability. Infrared variability is a powerful tool to discriminate between models of the circumstellar environment. The proposed mechanism of variable rim height may not be restricted to UXOR stars, but might be a general characteristic of intermediate-mass young stars.
Understanding how disks dissipate is essential to studies of planet formation. However, identifying exactly how dust and gas dissipates is complicated due to difficulty in finding objects clearly in ...the transition of losing their surrounding material. We use Spitzer IRS spectra to examine 35 photometrically-selected candidate cold disks (disks with large inner dust holes). The infrared spectra are supplemented with optical spectra to determine stellar and accretion properties and 1.3mm photometry to measure disk masses. Based on detailed SED modeling, we identify 15 new cold disks. The remaining 20 objects have IRS spectra that are consistent with disks without holes, disks that are observed close to edge-on, or stars with background emission. Based on these results, we determine reliable criteria for identifying disks with inner holes from Spitzer photometry and examine criteria already in the literature. Applying these criteria to the c2d surveyed star-forming regions gives a frequency of such objects of at least 4% and most likely of order 12% of the YSO population identified by Spitzer. We also examine the properties of these new cold disks in combination with cold disks from the literature. Hole sizes in this sample are generally smaller than for previously discovered disks and reflect a distribution in better agreement with exoplanet orbit radii. We find correlations between hole size and both disk and stellar masses. Silicate features, including crystalline features, are present in the overwhelming majority of the sample although 10 micron feature strength above the continuum declines for holes with radii larger than ~7 AU. In contrast, PAHs are only detected in 2 out of 15 sources. Only a quarter of the cold disk sample shows no signs of accretion, making it unlikely that photoevaporation is the dominant hole forming process in most cases.
An approach for the load flow solutions during normal and fault conditions has been presented in this paper. The A,B,C,D constants of the untransposed transmission lines have been treated as matrices ...and not as mere constants. The analysis has been carried out entirely in the phase frame of reference. The formulas developed are suitable for digital computation.
Going forward, digital twin will have significant impact towards nimble and efficient product development A physical product passes through digital stages and processes before it transforms into a ...physical entity. ...there is a wealth of product related information in the digital form. The concept of digital twin rests on the premise that a light weight / virtual model of the real product gives the designers / engineers a good chance to study, collect data and improvise on the product design and manufacturing process in real-time. ...digital twins impact the time to market performance of the product as virtual models reduce time and cost of alteration is faster. ...the manufacturing industry would benefit from "technology diffusion", thanks to early adoption of select technologies across financial services, retail or hospitality industry etc. ...more and more participants would be encouraged to participate in the world of complete connectivity that helps organizations realize the maximum efficiency.
General Statement:Following the discovery of lead-zinc deposits in the O'Connor Lake area t N.W.T. during the period 1948-50 t the Geological Survey of Canada decided to undertake a programme of ...geological mapping and examination of mineraI occurrences in the area during the year 1952 t under the supervision of Dr. A. B. Irwin, the then Resident Geologist of Yellowknife, N.W.T. After a shortwhile however, the present writer assumed full responsibility of the project and the mapping of the area was thence continued through the summers of 1952 and 1953 entirely by the present writer. The field work was carried out during the 1952 field season with the assistance of R.W.Moxham and during 1953 t with the assistance of B.E.Ferrill.Location and Access:The O'Connor Lake area is bounded by longitudes 111˚45'W and 112˚00'W and by latitudes 61˚15'N and 61030'N. The southwest corner of the area is about 120 miles southeast of Yellowknife, on the north shore of Great Slave Lake in the North West Territories.Chartered plane service from either Yellowknife or Hay River provides the easiest means of access to the area. Float-equipped Norseman or Beaver aircraft can land on the larger lakes during the period June 15 to September 15. Access to the area can be gained during the winter by a 35-mile tractor road from Rocher River (Taltson River) settlement near Great Slave Lake. A canoe route from Great Slave Lake, though infrequently used, ascends the Thubun River via a number of portages to the Thubun Lakes. Connecting streams within the map-area are not navigable by canoe.History of the Area.The O'Connor Lake area first received attention in 1948, although lead-zinc occurrences had been discovered by Frank Morrison of Yellowknife about two years earlier. The more important showings were developed to some extent by the O'Connor Lake Lead Syndicate during the period 1948-50. The main lead-zinc property consisting of MWK claims 1-2-3 was optioned in 1951 by American Yellowknife Mines Limited who carried out detailed geological mapping and extensive diamond drilling on the property during the period 1951-52. Underground development was started on MWK #1 vein, through a shaft 175 feet deep with drifting on the 150 foot level. Because of lower lead-zinc prices during the fall of 1952, further development was abandoned. There 15 at present no sustained activity in the area.Previous Work.The first and only previous survey of this region was in 1936, by J.F.Henderson (1939), who mapped the area on a scale of one inch to four miles. This map (Map No.525A,G.S.C.) covers the whole area of the Talts onLake sheet and distinguishes between the sediments and the granitic rocks. The area to the west was mapped by C.Camsell, 1914 and C.H.Stockwell, 1929, 1930 and 1931, on a scale of two inches to one mile and compiled by I.C.Brown (1950) as a preliminary paper.Present Work.Mapping of the area was done on a scale of two inches to one mile and was based on systematic pace-and-compass traverses spaced at intervals of one-quarter to one-half mile.
Negative phototactic orientation, step-up photophobic responses and light-induced action potentials have been studied in the ciliate Stentor coeruleus. A resolved action spectrum, based on fluence ...rate-response curves, is consistent with stentorin as the photoreceptor. Calcium flux blockers prolong the response time for ciliary stop and reversal and inhibit step-up photophobic responses. Drugs believed to affect the membrane-bound calcium pump likewise inhibit phobic responses. On the other hand, alpha-phosphatidic acid promotes Ca2+-influx and enhances the photophobic sensitivity of the organism, thus providing an unambiguous evidence for the role of Ca2+ influx. A change in the response time decreases the degree of phototactic orientation, indicating that negative phototaxis in this organism is brought about by subsequent phobic responses of individual rows of cilia as the associated photoreceptor granules experience an increase in light intensity when the organism rotates during forward locomotion in lateral light.
Divergence analysis in brinjal Mohanty, B.K; Prusti, A.M. (Orissa University of Agriculture and Technology, Bhawanipatna (India). Regional Research Station)
Journal of Maharashtra Agricultural Universities (India),
(Jan 2001), Letnik:
26, Številka:
1
Journal Article
Genetic divergence using Mahalanobis D2 statistic for five economic characters in 15 genotypes of brinjal (Solanum melongena L.) was studied. The pooled analysis revealed considerable variability ...among the test entries for all the characters. The accessions were grouped into six clusters which included two solitary group. Maximum intercluster (D2 = 971.15) was observed between the clusters VI and II followed by VI and IV. No relationship was noticed between geographic distribution and genetic divergence. Average fruit weight and number of fruits plant-1 contributed predominantly to total divergence. Multiple crossing among cluster II (BB 26 and Black Beauty), IV (Pusa Kranti and Bhawanipatna Local) and VI (H 8) was suggested for developing high yielding cultivars of brinjal with other desirable traits.
PDF
