491 research outputs found
Towards the derivation of stress intensity factors by parametric modelling of full-field thermoelastic data
No full textThermoelastic Stress Analysis (TSA) is a well-established full-field technique forexperimental stress analysis that has proved to be extremely effective for studying stress fields inthe vicinity of cracks. Recently, work has focused on the observation that the stress-sum contours(isopachics) obtained from TSA take the form of a cardioid. Genetic Algorithms (GAs) andDifferential Evolution (DE) have proved successful for accurate parameter estimation of thecardioids, thus allowing the SIFs to be calculated. Originally, some curve-fits indicated that a purecardioid form is inappropriate for the base model, especially for mixed-mode cracks. The deviationfrom the cardioid form has been shown to be due to higher-order terms within the stress function.The objective of the current paper is to use a modified version of the original methodology (thatfitted parameters to a single isopachic) to find the higher-order parameters from the entire data fieldobtained from the TSA
Curve fitting of mixed-mode isopachics
No full textRecent work has focused on exploiting the observation that the stress-sum contours
(isopachics), obtained from TSA, in the vicinity of the tip take the form of a simple curve – the
cardioid. The analysis made use of the cardioid nature of the isopachics by deriving
expressions for the SIFs in terms of the cardioid area and the positions of certain tangents to
the curve. Both Genetic Algorithms (GAs) and Differential Evolution (DE) have also proved
successful for parameter estimation, but some of the curve-fits indicated that the cardioid form
was inappropriate for the base model, particularly for mixed-mode cracks. The effect of cracktip
interaction has been explored and shows this has a small effect on the cardioid form. New,
higher resolution infra-red detectors have become available since the original data was
collected, so the object of the current paper is to use new techniques to extract the cardioid
form and use a GA to perform the curve fitting
Catalogue of Harris Institute Library, Woonsocket, R.I.: comprising subject, author, and title lists. Jan. 1, 1883.
No full textMode of access: Internet.With this is bound its: First supplement ... Providence, 1888
Single frequency erbium fiber external cavity semiconductor laser
No full textA novel external cavity configuration for stable single frequency operation of the semiconductor laser is demonstrated. By using an erbium doped fiber as the external cavity, longitudinal mode-hopping is suppressed, ensuring single frequency operation. Employing a 3m long fiber cavity, resolution-limited optical linewidths of a kHz are obtained.[This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing.
Suitability of empirical equations for estimating permanent settlement of railway foundation materials subject to cyclic loading with principal stress rotation
No full textThis paper uses the results of a series of laboratory tests with cyclic principal stress rotation to assess the suitability of a number of empirical equations for estimating the development of plastic settlements in railway track foundations. The laboratory tests were carried out on three sand-clay mixes representative of railway track foundation materials, in both free-to-drain and undrained conditions. The results of a non-linear regression analysis demonstrate that the drainage conditions are the key factor affecting the estimation accuracy of the models, with the clay content playing a secondary role. The correlation coefficient was generally higher in free-to-drain than in undrained conditions, and reduced slightly with increasing clay content.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Arizona hunting and trapping regulations
No full textThis annual booklet includes season dates, bag limits, hunt types, open areas, rules, regulations, drawing application details, and other requirements for the hunting of most big game, small game, other wildlife, and trapping in Arizona. Big game species covered in this regulation includes deer (mule deer and white-tailed deer), fall turkey, fall javelina, bighorn sheep, fall buffalo, fall bear, and mountain lion.In 2013, this publication split into: Arizona hunting regulations http://hdl.handle.net/2286/R.I.26906, and: Arizona trapping regulations http://hdl.handle.net/2286/R.I.26912For spring hunting regulations supplement, see: Spring turkey, javelina, buffalo and bear: hunt draw information http://hdl.handle.net/2286/R.I.2691
Optical spectroscopy of the low-mass X-ray binary GX 9+9
No full textPhase-resolved medium-resolution VLT spectroscopy of the low-mass X-ray binary GX 9+9 has revealed narrow C ill emission lines that move in phase relative to our new estimate of the ephemeris, and show a velocity amplitude of 230 +/not superset of 35 km s(-1). We identify the origin of these lines as coming from the surface of the donor star, thereby providing the first estimate of the mass function of f(M-1) >= 0.22 M-circle dot. Rotational broadening estimates together with assumptions for the mass donor give 0.07 <= q <= 0.35 and 182 <= K-2 <= 406 km s(-1). Despite a low-mass ratio, there is no evidence for a superhump in our data set. Doppler maps of GX 9+9 show the presence of a stream overflow, either in the form of material flowing downward along the accretion disc rim or in a similar fashion as occurs in high mass transfer rate cataclysmic variables known as the SW Sex stars. Finally, we note that the Bowen region in GX 9+9 is dominated by C in instead of N III emission as has been the case for most other X-ray binaries
The two Ephesian matrons: Drusiana’s story in the Acts of John as a possible Christian response to Milesian narrative
No full textIn this paper I try to demonstrate that the literary tradition of fabula Milesia
might lie in the background of both Petronius’ tale of the Milesian matron
and the story of Drusiana, told in the apocryphal Acts of John. This view is
supported by some elements common to the two stories: the location in
Ephesus; the theme of virtue, causing the women to long for death; the place
– a tomb – where their fidelity is put to test; and above all, the motif of return to life. And, if Petronius reflects the profane Milesian tradition, the author of the AJ criticizes it, aiming at re-using it to teach Christian morality
Detection of the irradiated donor in the LMXBs 4U 1636-536 (=V801 Ara) and 4U 1735-444 (=V926 Sco)
No full textPhase-resolved VLT spectroscopy of the bursting low-mass X-ray binaries 4U 1636-536/V801 Ara and 4U 1735-444/V926 Sco is presented. Doppler images of the N iiiλ4640 Bowen transition reveal compact spots which we attribute to fluorescent emission from the donor star and enable us to define a new set of spectroscopic ephemerides. We measure Kem= 277 ± 22 and 226 ± 22 km s−1 from the N iii spots in V801 Ara and V926 Sco, respectively, which represent strict lower limits to the radial velocity semi-amplitude of the donor stars. Our new ephemerides provide confirmation that light-curve maxima in V801 Ara and likely V926 Sco occur at superior conjunction of the donor star and hence photometric modulation is caused by the visibility of the X-ray heated donor. The velocities of He iiλ4686 and the broad Bowen blend are strongly modulated with the orbital period, with phasing supporting emission dominated by the disc bulge. In addition, a reanalysis of burst oscillations in V801 Ara, using our spectroscopic T0, leads to K1= 90–113 km s−1. We also estimate the K-corrections for all possible disc flaring angles and present the first dynamical constraints on the masses of these X-ray bursters. These are K2= 360 ± 74 km s−1, f(M) = 0.76 ± 0.47 M⊙ and q= 0.21–0.34 for V801 Ara and K2= 298 ± 83 km s−1, f(M) = 0.53 ± 0.44 M⊙ and q= 0.05–0.41 for V926 Sco. Disc flaring angles α≥ 12° and q≃ 0.26–0.34 are favoured for V801 Ara whereas the lack of K1 constraint for V926 Sco prevents tight constraints on this system. Although both binaries seem to have intermediate inclinations, the larger equivalent width of the narrow N iii line in V801 Ara at phase 0.5 relative to phase 0 suggests that it has the higher inclination of the two
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