181 research outputs found
Rotor fragment protection program: Statistics on aircraft gas turbine engine rotor failures that occurred in US commercial aviation during 1979
Statistical information relating to the number of gas turbine engine rotor failures which occurred during 1979 in commercial aviation service use is provided. The predominant failure mode involved blade fragments, 84 percent of which were contained. No uncontained disk failures occurred and although fewer rotor rim and seal failures occurred, 100 percent and 50 percent, respectively, were uncontained. Sixty-eight percent of the 157 rotor failures occurred during the take-off and climb stages of flight
Rotor burst protection program: Experimentation to provide guidelines for the design of turbine rotor burst fragment containment rings
Empirical guidelines for the design of minimum weight turbine rotor disk fragment containment rings made from a monolithic metal were generated by experimentally establishing the relationship between a variable that provides a measure of containment ring capability and several other variables that both characterized the configurational aspects of the rotor fragments and containment ring, and had been found from exploratory testing to have had significant influence on the containment process. Test methodology and data analysis techniques are described. Results are presented in graphs and tables
The isotropic correlation function of plane figures: the triangle case
The knowledge of the isotropic correlation function of a plane figure is
useful to determine the correlation function of the cylinders having the plane
figure as right-section and a given height as well as to analyze the out of
plane intensity collected in grazing incidence small-angle scattering from a
film formed by a particulate collection of these cylinders. The correlation
function of plane polygons can always be determined in closed algebraic form.
Here we report its analytic expression for the case of a triangle. The
expressions take four different forms that depend on the relative order among
the sides and the heights of the triangle.Comment: 11 pages, 2 figure
Rotor fragment protection program: Statistics on aircraft gas turbine ngine rotor failures that occurred in U.S. commercial aviation during 1978
This report presents statistical information relating to the number of gas turbine engine rotor failures which occurred in commercial aviation service use. The predominant failure involved blade fragments, 82.4 percent of which were contained. Although fewer rotor rim, disk, and seal failures occurred, 33.3%, 100% and 50% respectively were uncontained. Sixty-five percent of the 166 rotor failures occurred during the takeoff and climb stages of flight
A retrospective analysis of pegylated liposomal doxorubicin in ovarian cancer: Do we still need it?
Background: Ovarian cancer (OC) is the sixth most common cancer in women. Currently, carboplatin/ paclitaxel bevacizumab is the cornerstone of front-line treatment. Conversely, the therapeutic options for recurrent or progressive disease are not well defined. For platinum-sensitive patients the best therapeutic approach is still a re-challenge with a platinum-based regimen. Pegylated liposomal doxorubicin (PLD), is considered one of the most active therapeutic options for recurrent or progressive OC. In this retrospective mono-institutional analysis, we evaluated the impact of PLD on the outcome of OC patients. Patients and methods: We performed the retrospective study on a cohort of 108 patients with histologically confirmed serous papillary OC, followed at our Institution between 2001 and 2011. 80 patients were in stage III/IV and 55 of them received a second-line treatment. Thirty patients were treated with PLD. Both groups (PLD-treated versus PLD-untreated) underwent a median of 3 treatment lines and were prognostically balanced. The median follow-up was 60 months. Survival endpoints, toxicity and correlations between patients' baseline characteristics and treatment efficacy were evaluated. Results: Patients who had undergone PLD treatment (PLD group) showed a median overall survival (OS) of 45 months as compared to 65 months of patients not treated with PLD (PLD-free group) (HR 2.50 [0.95-6.67; p = 0.06]). Moreover, the median progression-free survival was 6 months in the PLD group versus 10 months in the PLD-free group (HR 1.75 [0.94-3.34; p = 0.07]). The overall objective response rate in II line treatment was 43% (13% in PLD group versus 57% in PLD-free group). Furthermore, we investigated survival endpoints in platinum-refractory patients who received PLD at least once during the course of disease. No OS advantage was achieved by PLD administration when compared to other therapeutic options (30 versus 32 months; HR 1.16 [0.31-4.34; p = 0.81]). No difference in term of toxicity was observed among different groups. Conclusions: No evidence of superiority if PLD was compared to alternative agents was found in this analysis, particularly in the platinum-refractory setting. Our findings indicate a modest therapeutic activity of PLD in OC. Analysis of cost/benefit of PLD in OC is eagerly awaited
Dynamics of the Destruction and Rebuilding of a Dipole Gap in Glasses
After a strong electric bias field was applied to a glass sample at
temperatures in the millikelvin range its AC-dielectric constant increases and
then decays logarithmically with time. For the polyester glass mylar we have
observed the relaxation of the dielectric constant back to its initial value
for several temperatures and histories of the bias field. Starting from the
dipole gap theory we have developed a model suggesting that the change of the
dielectric constant after transient application of a bias field is only partly
due to relaxational processes. In addition, non-adiabatic driving of tunneling
states (TSs) by applied electric fields causes long lasting changes in the
dielectric constant. Moreover, our observations indicate that at temperatures
below 50 mK the relaxation of TSs is caused primarily by interactions between
TSs.Comment: 4 pages, 4 figures, submitted to PR
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