162 research outputs found
Uncertainty of Estimated Rainflow Damage in Stationary Random Loadings and in Those Stationary per partes
The uncertainty of rainflow fatigue damage is evaluated for stationary loadings and for non-stationary switching loadings with a finite number of stationary states. The approach is based on confidence intervals constructed after direct analysis of stress-time histories. The accuracy of confidence intervals is verified first by numerical simulations, and then by experimental data measured in a mountain bike traveling under various driving and road surface conditions, yielding stationary and non-stationary switching loadings. Stationarity and non-stationarity of loading records is checked by a statistical method (run test). In experiments, a small set of records (validation set) is also collected and used to approximate the expected damage, which serves for verification purposes. Not only do numerical and experimental results confirm the correctness of the proposed confidence interval for damage, but they also emphasize its usefulness in real engineering applications
A comparison of methods for calculating notch tip strains and stresses under multiaxial loading
Selected methods for calculating notch tip strains and stresses in elastic–plastic isotropic bodies subjected to multiaxial monotonic loading were compared. The methods use sets of equations where hypothetical notch tip elastic strains and stresses obtained from FEM calculations serve as an input. The comparison was performed within two separate groups of methods: the first group consists of the methods intended for cases of multiaxial proportional loading and the second group deals with multiaxial non-proportional loading. Originally, the precision of the methods was validated by comparison with results obtained from elastic–plastic FEM analyses. Since computer performance at the time was lower than nowadays, verification of the proposed methods on FEM models with a finer mesh was needed. Such verification was carried out and is presented in this paper. The effect of various formulations of material stress–strain curve was also evaluated. 
Comparison of fatigue criteria for combined bending-torsion loading of nitrided and virgin specimens
This work deals with fatigue life of plasma-nitrided and virgin specimens made of a low-alloy high strength steel. Specimens were subjected to an in-phase combined bending-torsion loading. The plasma-nitrided specimens exhibited a significantly improved fatigue resistance. The criterion proposed by McDiarmid was found to be the most precise in the fatigue life prediction fo r virgin specimens. On the other hand, the Matake criterion was the most successful fo r nitrided specimens.Исследована усталостная долговечность азотированных в плазме образцов и исходных образцов из низколегированной высокопрочной стали. Испытания образцов проводились при синфазном совмещенном изгибе с кручением. Показано, что азотированные в плазме образцы обладают более высокой усталостной стойкостью. Установлено, что для образцов в исходном состоянии наибольшая точность прогнозирования усталостной долговечности обеспечивается при использовании критерия, предложенного Мак-Диармидом. С другой стороны, для азотированных образцов наиболее подходящим оказался критерий Матаке
Systematic validation of experimental data usable for verifying the multiaxial fatigue prediction methods
The paper discusses some of the issues, the researchers interested in verifying various multiaxial fatigue limit estimation solutions are facing to. Even recently, newly proposed criteria have been or are tested on dozens of experimental inputs. Papuga in [1] pointed out, that applicability of the most often used test batch is limited and only half of these data items is worth using for such purposes. This paper extends that analysis by describing the weak points of various data sets used in this domain for validating new proposals on multiaxial fatigue limit estimates. The conclusion from the extensive analysis is that the researchers should adopt other test sets only if they very well know their background. 
Ground-State Electromagnetic Moments of Calcium Isotopes
High-resolution bunched-beam collinear laser spectroscopy was used to measure
the optical hyperfine spectra of the Ca isotopes. The ground state
magnetic moments of Ca and quadrupole moments of Ca were
measured for the first time, and the Ca ground state spin was
determined in a model-independent way. Our results provide a critical test of
modern nuclear theories based on shell-model calculations using
phenomenological as well as microscopic interactions. The results for the
neutron-rich isotopes are in excellent agreement with predictions using
interactions derived from chiral effective field theory including three-nucleon
forces, while lighter isotopes illustrate the presence of particle-hole
excitations of the Ca core in their ground state.Comment: Accepted as a Rapid Communication in Physical Review
Spins, Electromagnetic Moments, and Isomers of 107-129Cd
The neutron-rich isotopes of cadmium up to the N=82 shell closure have been
investigated by high-resolution laser spectroscopy. Deep-UV excitation at 214.5
nm and radioactive-beam bunching provided the required experimental
sensitivity. Long-lived isomers are observed in 127Cd and 129Cd for the first
time. One essential feature of the spherical shell model is unambiguously
confirmed by a linear increase of the 11/2- quadrupole moments. Remarkably,
this mechanism is found to act well beyond the h11/2 shell
Isomer shift and magnetic moment of the long-lived 1/2 isomer in Zn: signature of shape coexistence near Ni
Collinear laser spectroscopy has been performed on the Zn
isotope at ISOLDE-CERN. The existence of a long-lived isomer with a few hundred
milliseconds half-life was confirmed, and the nuclear spins and moments of the
ground and isomeric states in Zn as well as the isomer shift were
measured. From the observed hyperfine structures, spins and
are firmly assigned to the ground and isomeric states. The magnetic moment
(Zn) = 1.1866(10) , confirms the spin-parity
with a shell-model configuration, in excellent
agreement with the prediction from large scale shell-model theories. The
magnetic moment (Zn) = 1.0180(12) supports a
positive parity for the isomer, with a wave function dominated by a 2h-1p
neutron excitation across the shell gap. The large isomer shift
reveals an increase of the intruder isomer mean square charge radius with
respect to that of the ground state:
= +0.204(6) fm, providing first evidence of shape coexistence.Comment: 5 pages, 4 figures, 1 table, Accepeted by Phys. Rev. Lett. (2016
Pierwotny chłoniak rozlany z dużych komórek B szyjki macicy — opis przypadku
We present a case of a 54-year-old woman treated for stage IIAE primary diffuse large B-cell lymphoma (DLBCL) of the uterine cervix. The CHOP chemotherapy regimen was started. After the diagnosis of lymphoma of DLBCL CD20+ type was confirmed, rituximab was added to the therapy. Within systemic therapy, the patient received two cycles of CHOP and six cycles of R-CHOP altogether. After treatment completion, total remission of the lesions was observed on computed tomography. Twenty-four months after therapy completion, the patient is disease-free with no signs of recurrence.Celem pracy była analiza przypadku 54-letniej pacjentki leczonej z powodu pierwotnego chłoniaka B-komórkowego szyjki macicy w stopniu IIAE. Leczenie rozpoczęto od chemioterapii według schematu CHOP. Po potwierdzeniu rozpoznania chłoniaka rozlanego z dużych komórek B CD20+ do leczenia dołączono rytuxymab. Łącznie, w ramach leczenia systemowego, chora otrzymała dwie serie chemioterapii według schematu CHOP oraz sześć serii chemioimmunoterapii według schematu R-CHOP. Efektem leczenia była całkowita remisja zmian nowotworowych. W dwadzieścia cztery miesiące po zakończeniu leczenia nie stwierdza się cech nawrotu choroby
High-precision quadrupole moment reveals significant intruder component in 13 33Al20 ground state
The electric quadrupole moment of the Al201333 ground state, located at the border of the island of inversion, was obtained using continuous-beam β-detected nuclear quadrupole resonance (β-NQR). From the measured quadrupole coupling constant νQ=2.31(4) MHz in an α-Al2O3 crystal, a precise value for the electric quadrupole moment is extracted: |Qs(Al33)|=141(3) mb. A comparison with large-scale shell model calculations shows that Al33 has at least 50% intruder configurations in the ground state wave function, favoring the excitation of two neutrons across the N=20 shell gap. Al33 therefore clearly marks the gradual transition north of the deformed Na and Mg nuclei towards the normal Z≥14 isotopesThis work was partly supported by the European Community FP6—Structuring the ERA—Integrated Infrastructure Initiative Contract EURONS No. RII3-CT-2004-506065, by the FWO-Vlaanderen, by the IAP programme of the Belgium Science Policy under Grants No. P6/23 and No. P7/12, by a grant of the MICINN (Spain) (FPA2011-29854), by the Nupnet network SARFEN (PRI-PIMMNUP-2011-1361), by MINECO (Spain) Centro de Excelencia Severo Ochoa Programme under Grant No. SEV-2012-0249, and by JSPS KAKENHI (Japan) Grants No. 21740204 and No. 15K05094. The experiment was carried out under Experimental Program E437
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