Presence of toxic and hazardous substances in recycled rubber surfaces; environmental distribution and toxicological implications

This thesis focuses on the study of recycled tire rubber employed as infill in artificial turf football pitches or as flooring in children's playgrounds, among other uses. Different families of chemical compounds such as polycyclic aromatic hydrocarbons, plasticisers, antioxidants and vulcanisation additives were determined in different recycled tire rubber matrices. In addition, the diffusion of these substances into the environment (air and water) and the potential bioaccessibility via oral ingestion were studied. For this purpose, different analytical methodologies were developed and validated. Due to the wide variety of the studied samples, different simple and sustainable sample preparation techniques were employed prior to analysis by gas chromatography coupled to tandem mass spectrometry

Articulación con rigidez controlable y dispositivo de medición de fuerza

El objeto de la invención es una articulación (1) con rigidez controlable y medición de fuerza, comprende un primer dispositivo (20), que comprende un marco (4) con una cara curva, conectado con un primer elemento motor (2), realizando este primer dispositivo (20) la regulación de la posición de la articulación (1), y un segundo dispositivo (22) que regula la rigidez de la articulación (1), que comprende un elemento de empuje (15) cuyo desplazamiento (D) determina una pre-compresión de un elemento resistivo (11) determinando de este modo la rigidez de la articulación (1), y el primer elemento motor (2) proporciona un giro al marco (4) tal que una rueda (8) del segundo dispositivo (22) recorre la cara curva del marco (4) generando una compresión (C) del elemento resistivo (11) a través de una barra de transmisión (7) asociada a dicha rueda (8) y al elemento resistivo (11)Peer reviewedConsejo Superior de Investigaciones Científicas, Universidad Politécnica de MadridB1 Patente sin examen previ

Sobre los estudios sociocríticos en China: una cuestión terminológica

La sociocrítica se ha convertido en los últimos años en un eje de análisis cultural en los estudios literarios. Sin embargo, en contraste con el crecimiento de esta perspectiva en otros contextos culturales, hay una notable ausencia de innovación en el entorno de los estudios literarios chinos. A pesar de la relevancia de las publicaciones de las décadas de 1980 y 1990, los estudios de la literatura china desde la perspectiva sociocrítica no han evolucionado. El presente artículo se centra en los principales problemas conceptuales y terminológicos que, al parecer, impiden que este enfoque sea utilizado y aceptado en China

Analyzing energy-efficient configurations in hexapod robots for demining applications

Purpose – Reducing energy consumption in walking robots is an issue of great importance in field applications such as humanitarian demining so as to increase mission time for a given power supply. The purpose of this paper is to address the problem of improving energy efficiency in statically stable walking machines by comparing two leg, insect and mammal, configurations on the hexapod robotic platform SILO6. Design/methodology/approach – Dynamic simulation of this hexapod is used to develop a set of rules that optimize energy expenditure in both configurations. Later, through a theoretical analysis of energy consumption and experimental measurements in the real platform SILO6, a configuration is chosen. Findings – It is widely accepted that the mammal configuration in statically stable walking machines is better for supporting high loads, while the insect configuration is considered to be better for improving mobility. However, taking into account the leg dynamics and not only the body weight, different results are obtained. In a mammal configuration, supporting body weight accounts for 5 per cent of power consumption while leg dynamics accounts for 31 per cent. Originality/value – As this paper demonstrates, the energy expended when the robot walks along a straight and horizontal line is the same for both insect and mammal configurations, while power consumption during crab walking in an insect configuration exceeds power consumption in the mammal configuration

Control architecture of the ATLAS 2020 lower-limb active orthosis

This paper outlines the control details implemented in the wearable gait exoskeleton ATLAS 2020 for improving the therapy of SMA children. This paper discusses the control challenges of a gait-training wearable exoskeleton for SMA children. Such device would also increase these children's quality of life, achieving a reduction of disability and increased functional independence.Peer reviewe

Control motion approach of a lower limb orthosis to reduce energy consumption

By analysing the dynamic principles of the human gait, an economic gait‐control analysis is performed, and passive elements are included to increase the energy efficiency in the motion control of active orthoses. Traditional orthoses use position patterns from the clinical gait analyses (CGAs) of healthy people, which are then de‐normalized and adjusted to each user. These orthoses maintain a very rigid gait, and their energy cosT is very high, reducing the autonomy of the user. First, to take advantage of the inherent dynamics of the legs, a state machine pattern with different gains in eachstate is applied to reduce the actuator energy consumption. Next, different passive elements, such as springs and brakes in the joints, are analysed to further reduce energy consumption. After an off‐line parameter optimization and a heuristic improvement with genetic algorithms, a reduction in energy consumption of 16.8% is obtained by applying a state machine control pattern, and a reduction of 18.9% is obtained by using passive elements. Finally, by combining both strategies, a more natural gait is obtained, and energy consumption is reduced by 24.6%compared with a pure CGA pattern

Hazardous compounds in recreational and urban recycled surfaces made from crumb rubber. Compliance with current regulation and future perspectives

Crumb rubber obtained from scrap tires is greatly employed for the construction of different facilities for sport, recreational and other uses. However, in recent years the concern about their safety and the related adult and children exposure to these surfaces is growing. This study aims a thorough chemical characterization encompassing 42 hazardous compounds, including polycyclic aromatic hydrocarbons (PAHs), phthalates, adipates, antioxidants and vulcanization agents in a wide range of crumb rubber from different surfaces. For the extraction of the target compounds, a method based on ultrasound-assisted extraction followed by gas chromatography-tandem mass spectrometry (UAE-GC–MS/MS) has been validated. Forty crumb rubber samples coming from synthetic turf football pitches, outdoor and indoor playgrounds, urban pavements, commercial tiles and granulates, and scrap tires, were analyzed. In addition, green alternative materials, such as sand and artificial turf based on cork granulate infill were included to compare the levels of the target compounds with those of crumb rubber. Most of the analyzed recycled surfaces meet the recent limits proposed by the European Commission for rubber granulates and mulches, although they exceed in several cases the maximum levels allowed for rubber consumer products. Besides, most of the other target compounds, including several of them considered as endocrine disruptors, were detected in the analyzed samples, reaching parts per million concentrations

Identifying ground-robot impedance to improve terrain adaptability in running robots

To date, running robots are still outperformed by animals, but their dynamic behaviour can be described by the same model. This coincidence means that biomechanical studies can reveal much about the adaptability and energy efficiency of walking mechanisms. In particular, animals adjust their leg stiffness to negotiate terrains with different stiffnesses to keep the total leg-ground stiffness constant. In this work, we aim to provide one method to identify ground-robot impedance so that control can be applied to emulate the aforementioned animal behaviour. Experimental results of the method are presented, showing well-differentiated estimations on four different types of terrain. Additionally, an analysis of the convergence time is presented and compared with the contact time of humans while running, indicating that the method is suitable for use at high speeds

Andador con mecanismo de asistencia en operaciones de levantado y sentado de un usuario

Andador (1) con mecanismo de asistencia en operaciones de levantado y sentado de un usuario (21) que comprende una estructura de soporte dotada de medios de desplazamiento (2, 3), un dispositivo de sujeción (20) del usuario al andador y un sistema de bloqueo de los medios de desplazamiento, donde la estructura de soporte comprende al menos un brazo pivotante (14) que guía al dispositivo de sujeción (20) del usuario (21), un soporte guía (11) fijado al andador (1) y que guía al brazo (14) y un módulo de control (15) que controla el sistema de bloqueo de los medios de desplazamiento (2,3) y que comprende medios de selección de un modo de trabajo del andador seleccionado entre “modo andar” y “modo sentarse/levantarse”Peer reviewedConsejo Superior de Investigaciones Científicas, Universidad Politécnica de MadridB1 Patente sin examen previ

An Active Knee Orthesis for the Physical Therapy of NEurological Disorders

This paper presents the design of a new robotic orthotic solution aimed at improving the rehabilitation of a number of neurological disorders (Multiple Sclerosis, Post-Polio and Stroke). These neurological disorders are the most expensive for the European Health Systems, and the personalization of the therapy will contribute to a 47% cost reduction. Most orthotic devices have been evaluated as an aid to in-hospital training and rehabilitation in patients with motor disorders of various origins. The advancement of technology opens the possibility of new active orthoses able to improve function in the usual environment of the patient, providing added benefits to state-of-the-art devices in life quality. The active knee orthosis aims to serve as a basis to justify the prescription and adaptation of robotic orthoses in patients with impaired gait resulting from neurological processes.Peer Reviewe