1,191 research outputs found
Identification of defects in composite laminates by comparison of mode shapes from electronic speckle pattern interferometry
A novel technique for identifying defects in carbon fibre reinforced plates has been developed. Firstly, modal analysis by impact excitation was performed to obtain the first five resonant frequencies for three defect-free and three defective specimens with in-plane fibre waviness. Then amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI) was used to obtain the mode shapes at these frequencies. The contours of the nodal regions visible in the mode shapes were extracted using a specially-developed algorithm employing density-based spatial clustering of applications with noise (DBSCAN). Fourier descriptors, that are invariant to rotations, translations, and scaling, were used to decompose the contours to reduce data dimensionality and make comparisons. The differences in contours between the two sets of specimens showed that the 4th and 5th mode shapes can be used for identifying the presence of the waviness defects. This technique for nodal region comparison was found to greatly simplify the comparison of fringe patterns for the purpose of damage assessment and could potentially be used as part of validation procedures
An evaluation of the factors that affect the health-related quality of life of children following myelosuppressive chemotherapy
PurposeThe purposes of this study, in children who were assessed 1 week after the administration of myelosuppressive chemotherapy were: to compare the total and subscale scores on a generic measure of health-related quality of life (HRQOL) to normative data from healthy children and describe the relationships between demographic, clinical, and symptom characteristics of children with cancer and generic and disease-specific dimensions of HRQOL.MethodsPatients (n =β61) were predominantly male (52.5%), minority (63.9%), and 14.7 years of age. Children completed the Memorial Symptom Assessment Scale for 10- to 18-year olds, the PedsQLβ’ Generic and Cancer Modules, and the Karnofsky Performance Status (KPS) scale 1 week after the start of a chemotherapy cycle.ResultsThe mean number of symptoms per patient was 10.6. Compared with the normative sample, children with cancer reported significantly lower scores for the total scale and all of the subscales except emotional and social functioning. No significant differences were found between any demographic characteristics and total or subscale scores on the generic or disease-specific measures of HRQOL. Lower KPS scores were associated with poorer generic and disease-specific HRQOL scores. In addition, a higher number of symptoms was associated with poorer generic and disease-specific HRQOL scores. Finally, higher symptom distress scores were associated with poorer generic and disease-specific HRQOL scores.ConclusionAmong the demographic, clinical, and symptom characteristics studied, poorer functional status and higher symptom burden were associated with significant decreases in HRQOL in children who received myelosuppressive chemotherapy
Improved Measurement of the Pseudoscalar Decay Constant
We present a new determination of the Ds decay constant, f_{Ds} using 5
million continuum charm events obtained with the CLEO II detector. Our value is
derived from our new measured ratio of widths for Ds -> mu nu/Ds -> phi pi of
0.173+/- 0.021 +/- 0.031. Taking the branching ratio for Ds -> phi pi as (3.6
+/- 0.9)% from the PDG, we extract f_{Ds} = (280 +/- 17 +/- 25 +/- 34){MeV}. We
compare this result with various model calculations.Comment: 23 page postscript file, postscript file also available through
http://w4.lns.cornell.edu/public/CLN
First Observation of and Decays
We have observed new channels for decays with an in the final
state. We study 3-prong tau decays, using the and
\eta\to 3\piz decay modes and 1-prong decays with two \piz's using the
channel. The measured branching fractions are
\B(\tau^{-}\to \pi^{-}\pi^{-}\pi^{+}\eta\nu_{\tau})
=(3.4^{+0.6}_{-0.5}\pm0.6)\times10^{-4} and \B(\tau^{-}\to
\pi^{-}2\piz\eta\nu_{\tau}
=(1.4\pm0.6\pm0.3)\times10^{-4}. We observe clear evidence for
substructure and measure \B(\tau^{-}\to
f_1\pi^{-}\nu_{\tau})=(5.8^{+1.4}_{-1.3}\pm1.8)\times10^{-4}. We have also
searched for production and obtain 90% CL upper limits
\B(\tau^{-}\to \pi^{-}\eta'\nu_\tau)<7.4\times10^{-5} and \B(\tau^{-}\to
\pi^{-}\piz\eta'\nu_\tau)<8.0\times10^{-5}.Comment: 11 page postscript file, postscript file also available through
http://w4.lns.cornell.edu/public/CLN
Search for the Decays B^0 -> D^{(*)+} D^{(*)-}
Using the CLEO-II data set we have searched for the Cabibbo-suppressed decays
B^0 -> D^{(*)+} D^{(*)-}. For the decay B^0 -> D^{*+} D^{*-}, we observe one
candidate signal event, with an expected background of 0.022 +/- 0.011 events.
This yield corresponds to a branching fraction of Br(B^0 -> D^{*+} D^{*-}) =
(5.3^{+7.1}_{-3.7}(stat) +/- 1.0(syst)) x 10^{-4} and an upper limit of Br(B^0
-> D^{*+} D^{*-}) D^{*\pm} D^\mp and
B^0 -> D^+ D^-, no significant excess of signal above the expected background
level is seen, and we calculate the 90% CL upper limits on the branching
fractions to be Br(B^0 -> D^{*\pm} D^\mp) D^+
D^-) < 1.2 x 10^{-3}.Comment: 12 page postscript file also available through
http://w4.lns.cornell.edu/public/CLNS, submitted to Physical Review Letter
Production in Two-Photon Interactions at CLEO
Using the CLEO detector at the Cornell storage ring, CESR, we study
the two-photon production of , making the first
observation of . We present the
cross-section for as a function of
the center of mass energy and compare it to that predicted by
the quark-diquark model.Comment: 10 pages, postscript file also available through
http://w4.lns.cornell.edu/public/CLN
Observation of the Decay
Using e+e- annihilation data collected by the CLEO~II detector at CESR, we
have observed the decay Ds+ to omega pi+. This final state may be produced
through the annihilation decay of the Ds+, or through final state interactions.
We find a branching ratio of [Gamma(Ds+ to omega pi+)/Gamma(Ds+ to eta
pi+)]=0.16+-0.04+-0.03, where the first error is statistical and the second is
systematic.Comment: 9 pages, postscript file also available through
http://w4.lns.cornell.edu/public/CLN
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