Initial State Interaction for the 20Ne + 130Te and 18O + 116Sn Systems at 15.3 AMeV from Elastic and Inelastic Scattering Measurements

Double charge exchange (DCE) reactions could provide experimentally driven information about nuclear matrix elements of interest in the context of neutrinoless double-β decay. To achieve this goal, a detailed description of the reaction mechanism is mandatory. This requires the full characterization of the initial and final-state interactions, which are poorly known for many of the projectile-target systems involved in future DCE studies. Among these, we intend to study the 20Ne + 130Te and 18O + 116Sn systems at 15.3 AMeV, which are particularly relevant due to their connection with the 130Te→130Xe and 116Cd→116Sn double-β decays. We measure the elastic and inelastic scattering cross-section angular distributions and compare them with theoretical calculations performed in the optical model, one-step distorted wave Born approximation, and coupled-channel approaches using the São Paulo double-folding optical potential. A good description of the experimental data in the whole explored range of transferred momenta is obtained provided that couplings with the 21+ states of the projectile and target are explicitly included within the coupled-channel approach. These results are relevant also in the analysis of other quasi-elastic reaction channels in these systems, in which the same couplings should be included.

An alternative approach for measuring yield stress and its application in Carbopol microgel

An innovative experimental apparatus for the direct measurement of yield stress was conceived and realized. It is based on a torsion pendulum equipped with a magnetic dipole and a rotating cylinder immersed in the material to be investigated. The pendulum equilibrium state depends on the mechanical torque applied due to an external magnetic induction field, elastic reaction of the suspension wire, and shear yield stress. Experimental results are reported showing that the behavior of the pendulum rotation angle, in different equilibrium conditions, provides evidence of the yield stress presence and enables its evaluation by equilibrium equations. The dependence on time of the equilibrium approach was also studied, contributing to shed light on the relaxation effect in the transition from a fluid-like to solid-like behavior, as well as on the eventual thixotropic effects in non-Newtonian fluids. The validity of the proposed technique and related experimental apparatus was tested in aqueous Carbopol solutions, with different weight percentages. The linear procedure, combined with the effectiveness and reliability of the proposed experimental method, candidates it to be used for the study of peculiar behaviors of other yield stress complex fluid such as blood, crude waxy oils, ice slurries, and coating layer used in the food industry and also for fault sliding in geodynamics.

Cutting off shears of workpieces by elastic reaction of bed

The technological capabilities of the shear cutting off method of the workpieces from the bar by the elastic reaction of the bed are analyzed. The shears design to increase their rigidity and efficiency is proposed.

The Temperature Dependent Elastic Moduli of Liquid Potassium

Near the melting point liquid alkali metals show positive dispersion, which can be described within generalized hydrodynamics as a visco-elastic reaction of the simple liquid. To understand an upward bending of the dispersion relation at small momentum transfer, treatment of pseudopotential theory on liquid potassium is performed at different temperatures in entire liquid regime. In the present study, we used the modified empty core potential due to Hasegawa et al. along with a local field correction due to Ichimaru-Utsumi (IU) to explain an electron-ion interaction. The potential used is composed of a full electron-ion interaction and a repulsive delta function to incorporate the orthogonalisation effect due to the s-core states. The temperature dependence of pair potential is calculated by using the damping term, exp(-πkBTr/2kF). While the expression for phonon dispersions are derived within the memory function formalism. Results for longitudinal phonon frequencies, and thus derived sound velocities and elastic modulii are compared with recent inelastic X-ray scattering experiment. It is found sufficient to carried temperature effect into the description only via the damping factor, keeping the volume of normal melting.

The Structural Static Analysis of Multi-Grooves Rectangular Aqueduct

Based on the structure and mechanical characteristics of large-sized multi-grooves rectangular aqueduct, the author deduced the calculation formulas of transverse elastic reaction force of double-body and three-body aqueducts with the conditions of elastic supporting by using the force principle in the method of structural mechanics; meanwhile, used 3D Finite Element Method to model and analyze the aqueduct; and contrasted the two calculated results to prove the accuracy of the obtained formulas. The conclusions show that calculating aqueducts with the formulas can meet the precision requirements of engineering design. It provides a simple and quick method for the design and construction in practice.

Dynamics of a Bistable Mechanism with Parallel Beams and Permanent Magnets

Besides the three main categories of bistable mechanisms such as latch-lock mechanisms, hinged multisegment mechanisms, and residual-compressive-stress buckled beams, a novel unsymmetrical bistable mechanism with a combined structure of permanent magnets and mechanical beams is proposed, and the bistability of such combined structure is analyzed based on the magnetic-charge model and material mechanics theory. The nonlinear combined force during snap-through procedure is calculated accurately, which is in accordance with that obtained by the experiments. The bistable characteristics such as the threshold snapping force, the traveling range, stable positions, and the elastic reaction force at the stable position can be adjusted freely by changing the magnet structure parameters and the relative distance among the three magnets. Finally, the dynamic response is analyzed theoretically and experimentally, which shows that the bistable structure has a good frequency distinguishing capacity for mechanical shock pulses.

Theoretic Analysis of Inner Force of Shield Tunnel According to Elastic Hinge Model

Elastic hinge model is one kind of reasonable models to analysis shield tunnel. However, no formulas are valid to calculate inner force caused by load of water pressure and elastic reaction. Mechanical equations of two kinds of load are built and inner force formulas are deduced. Results calculated by homogeneous ring model are contrasted with those by elastic hinge model and conclusion is derived. The contrast shows that the results according to elastic hinge model are more reasonable.