101,995 research outputs found
Ernesto Bitetti, guitarra (Argentina)
No full textConcierto interpretado por el guitarrista Ernesto Bitetti. Bitetti nació en Argentina y se formó con Ios maestros y concertistas G. Pomponio y Martínez Zárate. En 1961 obtuvo el Primer Premio del Concurso de la Sociedad Hebraica Argentina para inst rumentos de cuerdas. Al año siguiente se clasificó finalista en el "Coupe Internationale de Guitare" en París. Ha realizado ya tres giras por Europa, y obtenido grandes éxitos en Suiza, Italia, España, Bélgica, Inglaterra, Holanda y Francia. BITETTI es muy conocido además en América Latin
Reliable Numerical Approach for a Design of an Inflatable Moon/Mars Habitat based on Material Tests in the SAS Simulator
No full textOptical sensor system applicability for spacecraft tests
No full textThales Alenia Space Italy - Rome is carrying out a program of research and development in the field of optical sensors in order to verify its applicability in aerospace. Within this program particular emphasis has been placed on a type of optical sensor called Fiber Bragg Grating sensor (FBG). In the last decade the use of this technology in many fields worldwide has highlighted the characteristics and properties which can also be applied in the field of satellite telecommunications. For the sake of experimentation three tests simulated in the IUAIT Thermal Facilities, which gave useful results to assess the possibilities of using the FBG sensor, were carried out. Copyright ©2010 by the International Astronautical Federation. All rights reserved
Degradation of the surfaces exposed to the space environment
Get PDFThe presence of several atomic species in the LEO (Low Earth Orbits) could be considered one of the reasons for the degradation of the surfaces exposed to the Space Environment. At an average height of 400 Km (the altitude of International Space Station), the concentration of the main atomic species during the high sun activity are: 1.5 x 10(9) cm(-3) for atomic oxygen (AO), 1.6 x 10(8) cm(-3) for molecular nitrogen (N-2) and 1.4 x 10(8) m(-3) for atomic nitrogen (N). The energy with which the atoms collide with the surface of orbiting vehicle depends on the relative speed of the vehicle itself. For instance, the atoms colliding the International Space Station (ISS) (orbit average height: 400 Km; relative speed: 7.5 Km/s) have an energy of 8 eV for N-2, 5 eV for OA and 4 eV for N. The atomic oxygen is the most abundant species presents in LEO and it is considered the main responsible of the thermal, optical and mechanical alteration of the surfaces exposed to the Space Environment. Different hypothesis are reported in literature in order to explain the physical/chemical mechanisms that govern the material degradation in the Space, but no conclusion has been reached. In the energy range of few of eV, the main mechanism with which colliding atoms transfer its energy to the atoms of the surface is by phonons. In this paper the effect of an oxygen ion beam produced in the space environment simulator on materials for Space applications is studied in the frame of the thermal spike theory. Comparison between the measured erosion and the calculated one will be reported. The erosion mechanism will be modelled in order to understand the main thermodynamic parameters that govern the interaction between the atomic oxygen and the surface of the tested materials. (c) 2006 Elsevier Ltd. All rights reserved
Intraoperative examination (IOE) in pediatric extracranial tumors
No full textBACKGROUND AND OBJECTIVES: Intraoperative evaluation of surgical specimens by frozen sections (IOE) is required to distinguish benign and malignant lesions, assess surgical margins, and determine sample adequacy of biopsies. In the last years, it has been used also for therapeutic decisions, particularly in children, who may need other ancillary procedures, in case of malignancies. Our purpose was the evaluation of diagnostic accuracy, limits, and different role of IOE in pediatric pathology.
PATIENTS AND METHODS: From 1990 to 2001, 416 IOEs were performed in 341 children, affected by lymph node pathology, soft tissue tumors, neuroblastic tumors, gonadal germ cell, and stromal tumors, hepatic lesions, renal tumors, and others; the technique was also used to assess surgical margins during major surgeries. IOEs were obtained from Tru-cut biopsies (<1 cm(3)), wide biopsies (>1 cm(3)), or from the whole lesions, and the subsequent final diagnoses were classified as conordant, discordant, and deferred.
RESULTS: Three hundred seventy cases (88.9%) were concordant, 10 (2.4%) discordant, and 36 (8.6%) deferred. The disagreement was found in two small lymph node samples, three soft tissue tumors, one hepatoblastoma, one metastasis, and three surgical margins. The deferred diagnoses were related to lymph node and soft tissue lesions.
CONCLUSIONS: IOE in pediatric oncology may integrate the diagnostic process and supports the therapeutic guidelines of different tumors. In our study, the diagnostic concordance was satisfactory. A rational use of the technique and the awareness of its limits are, however, prerequisites to avoid the risk of overtreatment
Loss of Coolant Accident: parametric analysis of the initial period of the depressurization of a BWR vessel with the use of the RELAP4/MOD5 code" (in Italian)
No full textThe document (in Italian) deals with the analysis by computer code RELAP4 of experimental data measured in the PIPER facility. PIPER was installed at the Scalbatraio Laboratory managed by IIN (Istituto di Impianti Nucleari) of University of Pisa. PIPER consisted of a pressure vessel equipped with electrical heaters and rupture nozzle, other than suitable instrumentation (typically temperature and pressure transducers). Namely original instrumentation was developed to measure the jet thrust, the jet impingement loads and the load on internal components following the break opening and the propagation of the depressurization wave upstream from the rupture into the vessel. Pioneering RELAP applications to the analysis of experimental data demonstrated the validation level of the code. Namely, in this report, experimental data of blowdown are compared with code calculations results. The bases were put for better understanding of phenomena like Two-Phase Critical Flow (TPCF), depressurization rate, effect of initial subcooling and of relative position between initial collapsed level and elevation of exist nozzle axis. Key reported data (experiment and corresponding calculation results) are transient pressure and fluid temperatures at different positions in the vessel and in the exit nozzle
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