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Based on the nonlinear geometric relationship of the bulging angle and the bending angle, and the principle of virtual work and nonlinear constitutive relationship of Neo-Hookean incompressible hyperelastic material, a quasi-static mechanical model for pneumatic toothed soft actuator was established, considering the strain energy of the bottom, side walls, and front and rear walls. Considering the geometric nonlinearity and material nonlinearity, the proposed model could solve the configuration of the soft actuator at different driving pressures and terminal loads precisely and efficiently. The finite element simulation of the cantilevered-free soft actuator was conducted by Abaqus, and the corresponding experimental device was established. The simulation analysis and experimental investigation were performed at different driving pressures. A comparison of the results show that there is a positive linear correlation between the driving pressure and the bending angle of the soft actuator, and the prediction of the theoretical model agrees well with the simulation and experimental results. In addition, the distribution of the strain energy was analyzed. Based on the equal-curvature model, the configuration results of the soft actuator at terminal loads are basically consistent with those obtained by Abaqus. The proposed quasi-static mechanical modeling method provides a theoretical basis for the structural optimization design, performance improvement, and motion control of similar soft actuators.

Exploiting the random assignment of judges to corporate bankruptcy filings, we estimate financial costs of judicial inexperience. Despite new judges' prior legal experience, formal education, and rigorous hiring process, their public Chapter 11 cases spend 19% more time in bankruptcy, realize 31% higher legal and professional fees, and 21% lower creditor recovery rates. Examining possible mechanisms, we find that new judges take longer to rule on motions and cases assigned to these judges file more plans of reorganization. Conservative estimates suggest that minor policy adjustments could increase creditor recoveries by approximately $16.8 billion for the public firms in our sample. [ABSTRACT FROM AUTHOR]

It is a challenging problem to efficiently calculate and systematically analyze the motion laws and working gait of the inchworm-like soft robot. A simple mechanical model consisting of a rigid slider and a curved beam is established under quasi-static conditions, in order to realize quasi-static modeling and simulation analysis of the inchworm-like soft robot. First, based on the Euler-Bernoulli beam theory, the total potential energy expression of the beam is obtained. Next, combining the boundary conditions and the governing equation derived from the total potential energy based on the variational principle, a set of ordinary differential equations are established. Then, through discretization and dimensionlessness of those equations, a class of nonlinear algebraic equations for numerical solution is proposed. Finally, in the light of the contact situation between curved beam and ground as well as the viscous and slip condition of the system, the motion of the robot is divided into three stages. Through numerical calculations, the different configurations of the curved beam in different stages with the change of the initial curvature amplitude are obtained, which makes it possible to describe the law, the gait, and the net displacement of the soft robot in a motion cycle and solve the problem of movement connection of soft robots at different stages. The quasi-static method is characterized by high computational efficiency, which is more suitable for analyzing the motion configuration of soft robots.

This paper documents evidence that financial constraints increase firms' toxic emissions given that firms actively trade off abatement costs against potential legal liabilities. Exploring three quasi-natural experiments in which firms' financial resources are likely exogenously affected, we find that relaxing financial constraints reduces U.S. public firms' toxic releases. The effects of financial constraints on toxic releases are amplified when regulatory enforcement and external monitoring weaken. Overall, our evidence highlights the real effects of financial constraints in the form of environmental pollution, which is a costly negative externality imposed on society and public health. [ABSTRACT FROM AUTHOR]

We have analysed the recent data on D→ππ and $$K\bar K$$ decays from ARGUS, CLEO and E691. (i) We find that Bauer, Stech and Wirbel (BSW) model does fairly well in explaining all data if we assume that final state interactions simply rotate the amplitudes in the complex plane. However, to get a good fit one needs to raise D→ K transition amplitudes by (5-10)% over the BSW values and lower D→π amplitudes by a similar amount. (ii) We show that all the data can also be understood in a coupled channel inelastic model. (iii) We also find that the Isgur, Scora, Grinstein and Wise (ISGW) model-form factors, if extrapolated to small momentum transfers ( t) by a single pole formula, yield branching ratios too small in comparison to data. We propose an alternate scheme to interpolate between BSW form factors at t=0 and ISGW form factors at t=t. [ABSTRACT FROM AUTHOR]