Robotic Machine for High-Quality Shotcreting Process

This paper summarizes the development of the technologies used to produce high quality sprayed concrete layers by robotizing a commercial shotcreting machine and automating the process used in the tunnelling construction industry. The proposed method provides the control system with the information of the properties of the pumping process, controlling the quality of the concrete layer by adjusting in real-time the trajectory of the shotcreting machine. Given the unstructured nature of the tunnelling construction method there is an inherent difficulty in the automation of the shotcreting process. A complete description of the implemented control architecture of the shotcreting machine, the automated shotcreting process, the real-time quality layer prediction and the analysis of the tests made in real sites are shown in this paper.Peer reviewe

Robust high-accuracy high-speed continuous-time CMOS current comparator

The authors present a CMOS current comparator which employs nonlinear negative feedback to obtain high-accuracy (down to 1.5pA) and high-speed for low input currents (8ns at 50nA). The new structure features a speed improvement of more than two orders of magnitude for a 1 nA input current, when compared to the fastest reported to date

Uso pedagógico del blog: un proyecto de investigación-acción en la materia de Educación Física en Educación Secundaria

[EN] The goal of this projectwas to assess the effects of theuse of ablog as aresourcein Physical Education.108 students of 4thgradeof Secondary Education participated in the project, which lastedacompleteacademic year. Data was collected viaquestionnaire. Semi-structured interviews were also conducted to obtain more information.Results showthe highpedagogical value that students give to these digital tools[ES] El objetivo de este trabajo fue conocer los efectos del uso del blogcomo recurso de apoyo a la materia de Educación Física. 108 estudiantes de 4º de ESO participaron en la experiencia, desarrolladaduranteun curso escolar. Los datos se recogieron mediante un cuestionariodesarrolladoad hoc. También se realizaron entrevistas semi-estructuradas para obtener más información. Los resultados indican elgranvalor pedagógico que los estudiantes dan a estas herramientas digitalesS