Induced gravitational collapse at extreme cosmological distances: the case of GRB 090423

CONTEXT: The induced gravitational collapse (IGC) scenario has been introduced in order to explain the most energetic gamma ray bursts (GRBs), Eiso=10^{52}-10^{54}erg, associated with type Ib/c supernovae (SNe). It has led to the concept of binary-driven hypernovae (BdHNe) originating in a tight binary system composed by a FeCO core on the verge of a SN explosion and a companion neutron star (NS). Their evolution is characterized by a rapid sequence of events: [...]. AIMS: We investigate whether GRB 090423, one of the farthest observed GRB at z=8.2, is a member of the BdHN family. METHODS: We compare and contrast the spectra, the luminosity evolution and the detectability in the observations by Swift of GRB 090423 with the corresponding ones of the best known BdHN case, GRB 090618. RESULTS: Identification of constant slope power-law behavior in the late X-ray emission of GRB 090423 and its overlapping with the corresponding one in GRB 090618, measured in a common rest frame, represents the main result of this article. This result represents a very significant step on the way to using the scaling law properties, proven in Episode 3 of this BdHN family, as a cosmological standard candle. CONCLUSIONS: Having identified GRB 090423 as a member of the BdHN family, we can conclude that SN events, leading to NS formation, can already occur already at z=8.2, namely at 650 Myr after the Big Bang. It is then possible that these BdHNe originate stem from 40-60 M_{\odot} binaries. They are probing the Population II stars after the completion and possible disappearance of Population III stars.Comment: 9 pages, 9 figures, to appear on A&

An overview of R&D work in friction stir welding at SMU

Friction stir welding (FSW) is an innovative solid-state material joining method invented by The Welding Institute (TWI) in 1991 and has been one of the most significant joining technology developments in the last two decades. It has evolved into a process focused on joining arc weldable (5xxx and 6xxx) and unweldable (2xxx and 7xxx) aluminum alloys to a point where it can be implemented by the aerospace and automotive industries for their joining needs.Research towards the further extension of the process to join dissimilar metal combinations like Fe-Al and Al-Cu is currently underway. A few of the important advantages of FSW over conventional joining techniques include improved joint properties and performance, low-deformation of the workpieces, a significant reduction in production costs and the freeing of skilled labor for use in other tasks. Compared to the conventional arc-welding of aluminum alloys, FSW produces a smaller heat affected zone, and it also allows the successful joining of aluminum alloys, steel, titanium, and dissimilar alloys with a stronger joint

KARAPANDZIC FLAP FOR RECONSTRUCTION OF LOWER LIP IN A 18-MONTH OLD BOY WITH CONGENITAL AGAMMAGLOBULINEMIA AND ECTHYMA GANGRENOSUM. CASE REPORT

The reconstruction of lower lip in children is extremely rare and challenging procedure. The etiology in literature reveals trauma and infection. An 18-month boy was admitted with sepsis and pneumonia. Laboratory tests revealed congenital agammaglobulinemia. Necrosis of lower lip developed and was diagnosed as ecthyma gangrenosum. Blood culture was positive for Pseudomonas aeruginosa. Multiple abscess formations were found in abdominal wall and gluteal region and were treated by incisions. After spontaneous demarcation of necrotic tissue in lower lip the Karapandzic flap technique was used for reconstruction. Karapandzic flap can be used as optimal method for reconstruction of lower lip in children with satisfactory functional and aesthetic results.Key words: Karapandzic flap, ecthyma gangrenosum, reconstructio

Monitoring Weld of Weld Joint Penetration Based on Pool Geometrical Appearance The geometrical appearance of the weld pool contains sufficient information to determine full joint penetration in GTAW

ABSTRACT. Weld joint penetration monitoring and control are fundamental issues in automated welding. A skilled human operator can determine the weld penetration from the geometrical appearance of the weld pool. To emulate this using machine vision, a high-shutterspeed camera assisted with pulsed laser illumination is used to capture the clear image of the weld pool. The pool boundary is extracted by the developed realtime image processing algorithm. In order to emphasize the emulation of the human operator, general terms, i.e., size, shape and geometrical appearance, are used for the conceptual discussion, whereas more specific terms such as length, width, and rear angles are used in the detailed analysis. In particular, the size will be specified by the pool width and length, and the shape will be defined using the proposed rear angle of the weld pool. The geometrical appearance is described by a combination of the size and shape parameters. To investigate the relationships, which could be complicated, between the weld penetration and different parameters, neural networks are used because of their capability for modeling complicated nonlinear functions. Extensive experiments have been developed to measure the weld penetration from the captured image in 200 ms using the neural network and real-time image processing