Rafael Agujetas

Dr. Rafael Agujetas

orcid

Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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25 October 2020 in Agriculture
Verified
Journal Article
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MGMª Soledad Fernández García
Mª Soledad Fernández García
PVPablo Vidal-Lopez
Pablo Vidal-Lopez
DRDesirée Rodríguez-Robles
Desirée Rodríguez-Robles
JVJosé Ramón Villar-García
José Ramón Villar-García
RARafael Agujetas
Rafael Agujetas
Greenhouses had to be designed to sustain permanent maintenance and crop loads as well as the site-specific climatic conditions, with wind being the most damaging. However, both the structure and foundation are regularly empirically calculated, which could lead to structural inadequacies or cost ineffectiveness. Thus, in this paper, the structural assessment of a multi-tunnel greenhouse was carried out. Firstly, wind loads were assessed through computational fluid dynamics (CFD). Then, the buckling failure mode when either the European Standard (EN) or the CFD wind loads were contemplated was assessed by a finite element method (FEM). Conversely to the EN 13031-1, CFD wind loads generated a suction in the 0–55° region of the first tunnel and a 60% reduction of the external pressure coefficients in the third tunnel was not detected. Moreover, the first-order buckling eigenvalues were reduced (32–57%), which resulted in the need for a different calculation method (i.e., elastoplastic analysis), and global buckling modes similar to local buckling shape were detected. Finally, the foundation was studied by the FEM and a matrix method based on the Wrinkler model. The stresses and deformations arising from the proposed matrix method were conservative compared to those obtained by the FEM.

30 May 2018 in BioMedical Engineering OnLine
Verified
Journal Article
Open access
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RARafael Agujetas
Rafael Agujetas
MGM. R. González-Fernández
M. R. González-Fernández
JNJ. M. Nogales-Asensio
J. M. Nogales-Asensio
JMJosé María Montanero
José María Montanero
Fractional flow reverse (FFR) is the gold standard assessment of the hemodynamic significance of coronary stenoses. However, it requires the catheterization of the coronary artery to determine the pressure waveforms proximal and distal to the stenosis. On the contrary, computational fluid dynamics enables the calculation of the FFR value from relatively non-invasive computed tomography angiography (CTA). We analyze the flow across idealized highly-eccentric coronary stenoses by solving the Navier–Stokes equations. We examine the influence of several aspects (approximations) of the simulation method on the calculation of the FFR value. We study the effects on the FFR value of errors made in the segmentation of clinical images. For this purpose, we compare the FFR value for the nominal geometry with that calculated for other shapes that slightly deviate from that geometry. This analysis is conducted for a range of stenosis severities and different inlet velocity and pressure waveforms. The errors made in assuming a uniform velocity profile in front of the stenosis, as well as those due to the Newtonian and laminar approximations, are negligible for stenosis severities leading to FFR values around the threshold 0.8. The limited resolution of the stenosis geometry reconstruction is the major source of error when predicting the FFR value. Both systematic errors in the contour detection of just 1-pixel size in the CTA images and a low-quality representation of the stenosis surface (coarse faceted geometry) may yield wrong outcomes of the FFR assessment for an important set of eccentric stenoses. On the contrary, the spatial resolution of images acquired with optical coherence tomography may be sufficient to ensure accurate predictions for the FFR value.

1 November 2020 in Computer Methods and Programs in Biomedicine
Verified
Journal Article
Closed access
RARafael Agujetas
Rafael Agujetas
RBR. Barrio-Perotti
R. Barrio-Perotti
CFConrado Ferrera
Conrado Ferrera
Adrián PandalAdrián Pandal
Adrián Pandal
DWD.K. Walters
D.K. Walters
Ana Fernández-TenaAna Fernández-Tena
Ana Fernández-Tena

6 June 2022 in Sensors
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Journal Article
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DJDaniel Rodríguez Jorge
Daniel Rodríguez Jorge
JGJavier Bermejo García
Javier Bermejo García
AJAshwin Jayakumar
Ashwin Jayakumar
RMRafael Lorente Moreno
Rafael Lorente Moreno
RARafael Agujetas
Rafael Agujetas
Francisco RomeroFrancisco Romero
Francisco Romero
Soft exosuits stand out when it comes to the development of walking-assistance devices thanks to both their higher degree of wearability, lower weight, and price compared to the bulkier equivalent rigid exoskeletons. In cable-driven exosuits, the acting force is driven by cables from the actuation system to the anchor points; thus, the user’s movement is not restricted by a rigid structure. In this paper, a 3D inverse dynamics model is proposed and integrated with a model for a cable-driven actuation to predict the required motor torque and traction force in cables for a walking-assistance exosuit during gait. Joint torques are to be shared between the user and the exosuit for different design configurations, focusing on both hip and ankle assistance. The model is expected to guide the design of the exosuit regarding aspects such as the location of the anchor points, the cable system design, and the actuation units. An inverse dynamics analysis is performed using gait kinematic data from a public dataset to predict the cable forces and position of the exosuit during gait. The obtained joint reactions and cable forces are compared with those in the literature, and prove the model to be accurate and ready to be implemented in an exosuit control scheme. The results obtained in this study are similar to those found in the literature regarding the walking study itself as well as the forces under which cables operate during gait and the cable position cycle.

23 July 2024 in Sensors
Verified
Journal Article
Open access
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Rabé AnderssonRabé Andersson
Rabé Andersson
JGJavier Bermejo García
Javier Bermejo García
RARafael Agujetas
Rafael Agujetas
MCMikael Cronhjort
Mikael Cronhjort
JCJosé Chilo
José Chilo
Gait monitoring using hip joint angles offers a promising approach for person identification, leveraging the capabilities of smartphone inertial measurement units (IMUs). This study investigates the use of smartphone IMUs to extract hip joint angles for distinguishing individuals based on their gait patterns. The data were collected from 10 healthy subjects (8 males, 2 females) walking on a treadmill at 4 km/h for 10 min. A sensor fusion technique that combined accelerometer, gyroscope, and magnetometer data was used to derive meaningful hip joint angles. We employed various machine learning algorithms within the WEKA environment to classify subjects based on their hip joint pattern and achieved a classification accuracy of 88.9%. Our findings demonstrate the feasibility of using hip joint angles for person identification, providing a baseline for future research in gait analysis for biometric applications. This work underscores the potential of smartphone-based gait analysis in personal identification systems.

28 November 2018 in Biomechanics and Modeling in Mechanobiology
Verified
Journal Article
Closed access
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RARafael Agujetas
Rafael Agujetas
Alfonso C. MarcosAlfonso C. Marcos
Alfonso C. Marcos
José Ignacio Fernández-VigoJosé Ignacio Fernández-Vigo
José Ignacio Fernández-Vigo
JMJosé María Montanero
José María Montanero