133 research outputs found
Analisi agli Elementi Finiti delle Strutture Alari di un prototipo di velivolo PrandtlPlane: verifiche e possibili modifiche
Questa tesi ha come obiettivo la verifica dello stato di tensione nelle strutture alari di un prototipo di velivolo anfibio Prandtlplane attraverso l'analisi agli elementi finiti. Con l'utilizzo dei software MSC Patran e Nastran è stato creato un modello semplificato degli elementi costituenti le strutture investigate, al quale sono stati applicati i carichi aerodinamici simmetrici secondo la normativa CS-LSA. In base ai risultati ottenuti da queste prime analisi, sono stati creati ed analizzati altri due modelli. Nel primo caso gli obiettivi di resistenza desiderati sono stati raggiunti per mezzo di modifiche ai longheroni e nel secondo una riduzione di peso è stata ottenuta tramite l'impiego di longheroni in alluminio e modifiche ai laminati del rivestimento delle ali.
This thesis aims to verify the stress state in the wing structures of a prototype of amphibious Prandtlplane trough finite elements analisys. Using the software MSC Patran and Nastran a simplified model of the elements constituting the investigated structures has been created, to which were applied the symmetrical loads required by the regulations CS-LSA. Based on the results obtained from the analisys, were created and analized two more models. In the first case the required targets of structural strength have been achieved through modifications to the wing spars and in the second case a weight reduction has been achieved trough the utilization of aluminum spars and modifications to the laminates of the wing skin.
Diese Arbeit zielt darauf ab, den Spannungszustand in den Flügelstrukturen eines Prandtlplane_Amphibienflugzeug-Prototypes durch die Finite-Elemente-Analyse zu überprüfen. Mit dem Einsatz der Software MSC Patran und Nastran wurde ein vereinfachtes Modell der Elemente geschaffen, welche die analysierten Strukturen konstituiren. Hierzu wurden die symmetrischen aerodynamischen Lasten nach der Norm CS-LSA angewandt. Aufgrund der erhaltenen Ergebnisse wurden Zwei weitere Modelle geschaffen und analysiert. Im ersten Fall wurden die gewünschten Ziele der Zugfestigkeit durch Änderungen der Fluegelholme erreicht, im zweiten Fall wurde eine Gewichtsreduzierung unter Verwendung von Aluminiumholmen und durch Änderungen der Flügelummantelungslaminate erhalten
Predictors of Early Thrombotic Events in Adult Patients with Acute Myeloid Leukemia: A Real-World Experience
Information regarding the incidence and the prognostic impact of thrombotic events (TE) in non-promyelocytic acute myeloid leukemia (AML) is sparse. Although several risk factors associated with an increased risk of TE development have been recognized, we still lack universally approved guidelines for identification and management of these complications. We retrospectively analyzed 300 consecutive patients with newly diagnosed AML. Reporting the incidence of venous TE (VTE) and arterial TE (ATE) was the primary endpoint. Secondarily, we evaluated baseline patient- and disease-related characteristics with a possible influence of VTE-occurrence probability. Finally, we evaluated the impact of TE on survival. Overall, the VTE incidence was 12.3% and ATE incidence was 2.3%. We identified three independent predictors associated with early-VTE: comorbidities (p = 0.006), platelets count >50x10e9/L (p = 0.006), and a previous history of VTE (p = 0.003). Assigning 1 point to each variable, we observed an overall cumulative incidence of VTE of 18.4% in the high-risk group
(>2 points) versus 6.4% in the low-risk group (0–1 point), log-rank = 0.002. Overall, ATE, but not VTE, was associated with poor prognosis (p < 0.001). In conclusion, TE incidence in AML patients is not negligible. We proposed an early-VTE risk score that could be useful for a proper management of VTE prophylaxis
Images of the Early Universe from the BOOMERanG experiment
The CMB is the fundamental tool to study the properties of the early universe and of the
universe at large scales. In the framework of the Hot Big Bang model, when we look to
the CMB we look back in time to the end of the plasma era, at a redshift ~ 1000, when
the universe was ~ 50000 times younger, ~ 1000 times hotter and ~ 10^9 times denser
than today. The image of the CMB can be used to study the physical processes there, to
infer what happened before, and also to study the background geometry of our Universe
Measurement of a Peak in the Cosmic Microwave Background Power Spectrum from the North American test flight of BOOMERANG
We describe a measurement of the angular power spectrum of anisotropies in
the Cosmic Microwave Background (CMB) from 0.3 degrees to ~10 degrees from the
North American test flight of the BOOMERANG experiment. BOOMERANG is a
balloon-borne telescope with a bolometric receiver designed to map CMB
anisotropies on a Long Duration Balloon flight. During a 6-hour test flight of
a prototype system in 1997, we mapped > 200 square degrees at high galactic
latitudes in two bands centered at 90 and 150 GHz with a resolution of 26 and
16.6 arcmin FWHM respectively. Analysis of the maps gives a power spectrum with
a peak at angular scales of ~1 degree with an amplitude ~70 uK.Comment: 5 pages, 1 figure LaTeX, emulateapj.st
ℓ-space spectroscopy of the Cosmic Microwave Background with the BOOMERanG experiment
The BOOMERanG experiment has recently produced detailed maps of the Cosmic Microwave Background, where sub-horizon structures are resolved with good signal to noise ratio. A power spectrum (spherical harmonics) analysis of the maps detects three peaks, at multipoles ℓ = (213_(-13)^(+10)),(541_(-32)^(+20))(845_(-25)^(+12)). In this paper we discuss the data analysis and the implications of these results for cosmology
Cosmological Parameters from the 2003 flight of BOOMERANG
We present the cosmological parameters from the CMB intensity and
polarization power spectra of the 2003 Antarctic flight of the BOOMERANG
telescope. The BOOMERANG data alone constrains the parameters of the
CDM model remarkably well and is consistent with constraints from a
multi-experiment combined CMB data set. We add LSS data from the 2dF and SDSS
redshift surveys to the combined CMB data set and test several extensions to
the standard model including: running of the spectral index, curvature, tensor
modes, the effect of massive neutrinos, and an effective equation of state for
dark energy. We also include an analysis of constraints to a model which allows
a CDM isocurvature admixture.Comment: 18 pages, 10 figures, submitted to Ap
A Measurement of the Angular Power Spectrum of the CMB Temperature Anisotropy from the 2003 Flight of Boomerang
We report on observations of the Cosmic Microwave Background (CMB) obtained
during the January 2003 flight of Boomerang . These results are derived from
195 hours of observation with four 145 GHz Polarization Sensitive Bolometer
(PSB) pairs, identical in design to the four 143 GHz Planck HFI polarized
pixels. The data include 75 hours of observations distributed over 1.84% of the
sky with an additional 120 hours concentrated on the central portion of the
field, itself representing 0.22% of the full sky. From these data we derive an
estimate of the angular power spectrum of temperature fluctuations of the CMB
in 24 bands over the multipole range (50 < l < 1500). A series of features,
consistent with those expected from acoustic oscillations in the primordial
photon-baryon fluid, are clearly evident in the power spectrum, as is the
exponential damping of power on scales smaller than the photon mean free path
at the epoch of last scattering (l > 900). As a consistency check, the
collaboration has performed two fully independent analyses of the time ordered
data, which are found to be in excellent agreement.Comment: 11 pages, 7 figures, 3 tables. High resolution figures and data are
available at http://cmb.phys.cwru.edu/boomerang/ and
http://oberon.roma1.infn.it/boomerang/b2
Measuring CMB Polarization with BOOMERANG
BOOMERANG is a balloon-borne telescope designed for long duration (LDB)
flights around Antarctica. The second LDB Flight of BOOMERANG took place in
January 2003. The primary goal of this flight was to measure the polarization
of the CMB. The receiver uses polarization sensitive bolometers at 145 GHz.
Polarizing grids provide polarization sensitivity at 245 and 345 GHz. We
describe the BOOMERANG telescope noting changes made for 2003 LDB flight, and
discuss some of the issues involved in the measurement of polarization with
bolometers. Lastly, we report on the 2003 flight and provide an estimate of the
expected results.Comment: 12 pages, 8 figures, To be published in the proceedings of "The
Cosmic Microwave Background and its Polarization", New Astronomy Reviews,
(eds. S. Hanany and K.A. Olive). Fixed typos, and reformatted citation
Searching for non Gaussian signals in the BOOMERanG 2003 CMB maps
We analyze the BOOMERanG 2003 (B03) 145 GHz temperature map to constrain the
amplitude of a non Gaussian, primordial contribution to CMB fluctuations. We
perform a pixel space analysis restricted to a portion of the map chosen in
view of high sensitivity, very low foreground contamination and tight control
of systematic effects. We set up an estimator based on the three Minkowski
functionals which relies on high quality simulated data, including non Gaussian
CMB maps. We find good agreement with the Gaussian hypothesis and derive the
first limits based on BOOMERanG data for the non linear coupling parameter f_NL
as -300<f_NL<650 at 68% CL and -800<f_NL<1050 at 95% CL.Comment: accepted for publication in ApJ. Letter
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