Dynamic model of a rotating flexible arm-flexible root mechanism driven by a shaft flexible in torsion

Abstract. This paper presents a dynamic model of a rotating flexible beam carrying a payload at its tip. The model accounts for the driving shaft and the arm root flexibilities. The finite element method and the Lagrangian dynamics are used in deriving the equations of motion with the small deformation theory assumptions and the Euler-Bernoulli beam theory. The obtained model is a nonlinear-coupled system of differential equations. The model is simulated for different combinations of shaft and root flexibilities and arm properties. The simulation results showed that the root flexibility is an important factor that should be considered in association with the arm and shaft flexibilities, as its dynamics influence the motor motion. Moreover, the effect of system non-linearity on the dynamic behavior is investigated by simulating the equivalent linearized system and it was found to be an important factor that should be considered, particularly when designing a control strategy for practical implementation

The observation of long-range three-body Coloumb effects in the decay of 16Ne

The interaction of an $E/A$=57.6-MeV $^{17}$Ne beam with a Be target was used to populate levels in $^{16}$Ne following neutron knockout reactions. The decay of $^{16}$Ne states into the three-body $^{14}$O+$p$+$p$ continuum was observed in the High Resolution Array (HiRA). For the first time for a 2p emitter, correlations between the momenta of the three decay products were measured with sufficient resolution and statistics to allow for an unambiguous demonstration of their dependence on the long-range nature of the Coulomb interaction. Contrary to previous experiments, the intrinsic decay width of the $^{16}$Ne ground state was found to be narrow ($\Gamma<60$~keV), consistent with theoretical estimates.Comment: 6 pages, 5 figure

Stretched states in B 12,13 with the (d,α) reaction

The (d,α) reaction is highly selective, favoring final states in which the removed neutron and proton are completely aligned in a J=2j configuration. We have studied the C14,15(d,α)B12,13 reactions in inverse kinematics using the Helical Orbit Spectrometer (HELIOS) at Argonne National Laboratory. In B12, the reaction strongly favors the population of a known 3+ state at 5.61 MeV, and for B13, we observe a possible unreported doublet of states at high excitation energy, probably corresponding to the B12(3+) state coupled to the 1s1/2 neutron from the C15 ground state. In contrast to single-nucleon transfer, deuteron-transfer reactions have not been widely studied with exotic nuclei

Study of valence neutrons in \u3csup\u3e136\u3c/sup\u3eXe with HELIOS

The single-neutron adding (d,p) reaction has been performed on 136Xe in inverse kinematics at 10 MeV/u. The position, time-of-flight, and energy of the outgoing protons were analyzed by the new helical orbit spectrometer, HELIOS, at Argonne National Laboratory. An excitation-energy resolution of ≲100 keV was obtained in the outgoing proton spectra. The experimental setup is described, along with a technique of extracting absolute cross sections. Data are shown which illustrate the performance of the device. This measurement clearly demonstrates the potential of HELIOS for future heavy radioactive-beam studies

Ground-state properties of H 5 from the He 6 (d, He 3) H 5 reaction

We have studied the ground state of the unbound, very neutron-rich isotope of hydrogen H5, using the He6(d,He3)H5 reaction in inverse kinematics at a bombarding energy of E(He6)=55A MeV. The present results suggest a ground-state resonance energy ER=2.4±0.3 MeV above the H3+2n threshold, with an intrinsic width of Γ=5.3±0.4 MeV in the H5 system. Both the resonance energy and width are higher than those reported in some, but not all previous studies of H5. The previously unreported He6(d,t)Heg.s.5 reaction is observed in the same measurement, providing a check on the understanding of the response of the apparatus. The data are compared to expectations from direct two-neutron and dineutron decay. The possibility of excited states of H5 populated in this reaction is discussed using different calculations of the He6→H5+p spectroscopic overlaps from shell-model and ab initio nuclear-structure calculations

Structure of C 14 and B 14 from the C 14,15 (d, He 3) B 13,14 reactions

We have studied the C14,15(d,He3)B13,14 proton-removing reactions in inverse kinematics. The (d,He3) reaction probes the proton occupation of the target ground state, and also provides spectroscopic information about the final states in B13,14. The experiments were performed using C14,15 beams from the ATLAS accelerator at Argonne National Laboratory. The reaction products were analyzed with the HELIOS device. Angular distributions were obtained for transitions from both reactions. The C14-beam data reveal transitions to excited states in B13 that suggest configurations with protons outside the π(0p3/2) orbital, and some possibility of proton cross-shell 0p-1s0d excitations, in the C14 ground state. The C15-beam data confirm the existence of a broad 2- excited state in B14. The experimental data are compared to the results of shell-model calculations

Fusion reactions with the one-neutron halo nucleus C15

The structure of C15, with an s1/2 neutron weakly bound to a closed-neutron shell nucleus C14, makes it a prime candidate for a one-neutron halo nucleus. We have for the first time studied the cross section for the fusion-fission reaction C15+Th232 at energies in the vicinity of the Coulomb barrier and compared it to the yield of the neighboring C14+Th232 system measured in the same experiment. At sub-barrier energies, an enhancement of the fusion yield by factors of 2-5 was observed for C15, while the cross sections for C14 match the trends measured for C12,13. © 2011 American Physical Society