No abstract

To generate enough thrust for a Tunnel Boring Machine (TBM) to excavate a soil and advance, several jacks are typically used to apply force to the last installed ring that acts as a reaction frame. These loads generate bursting stresses that might cause cracks in the longitudinal direction of the segments. Many studies dedicated to evaluating this phenomenon focus mainly on elements with similar height-to-length ratios. To cover the wide variety of dimensions and load application patterns, additional experimental assessments are required. The objectives of the present paper are to extend the study of with different height-to-length ratios subjected to concentrated loads and to validate analytical formulations for the verification of concrete segments in SLS and ULS. To accomplish this, an experimental program was constructed using small-scale specimens with and without fibre reinforcement. The results obtained were used to validate the formulations derived from a struts-and-ties model. Finally, an application of the formulation proposed to the case study of Line 9 in Barcelona is presented. This study represents a contribution towards the development of simplified tools for the design of segmented linings both in the SLS and in the ULS.

No abstract

The design of effective supporting matrices to efficiently cycle Si nanoparticles is often difficult to achieve and requires complex preparation strategies. In this work, we present a simple synthesis of low-cost and environmentally benign aAnatase TiO nanoparticles as buffering filler for Si nanoparticles (Si@TiO ). The average anatase TiO crystallite size was approximately 5 nm. A complete structural, morphological, and electrochemical characterization was performed. Electrochemical test results show very good specific capacity values of up to 1000 mAh g and cycling at several specific currents, ranging from 500 to 2000 mA g , demonstrating a very good tolerance to high cycling rates. Postmortem morphological analysis shows very good electrode integrity after 100 cycles at 500 mA g specific current.

Fe3O4 nanoparticles synthesized by a base catalyzed method are tested in an All-Solid-State (ASLB) battery using a sulfide electrolyte. The pristine nanoparticles were morphologically characterized showing an average size of 12 nm. The evaluation of the electrochemical properties shows high specific capacity values of 506 mAhg−1 after 350 cycles at a specific current of 250 mAg−1, with very high stability and coulombic efficiency.