Este artículo sintetiza algunos aspectos del proyecto “Hierro y bronce. Criterios para la valoración y conservación de la herrería artística en el patrimonio arquitectónico del Uruguay”[i], cuyo objetivo es establecer los atributos patrimoniales de los elementos ornamentales metálicos asociados a fachadas del patrimonio arquitectónico nacional y contribuir a su difusión, puesta en valor y conservación. A lo largo de la investigación se abordan los aspectos socioculturales, artísticos, formales, técnicos y, por último, los relativos al deterioro de estos elementos y las pautas para su preservación y restauración. La metodología se basa en el estudio de fuentes primarias, éditas e inéditas, en la revisión de bibliografía especializada y en el trabajo de campo sobre una muestra representativa de elementos ornamentales metálicos aplicados a las fachadas de la arquitectura montevideana. Fue relevado un total de 250 edificios, correspondientes a los distintos períodos que distinguimos en la evolución de la herrería local entre finales del siglo XVIII y mediados del siglo XX. Se trata de un aporte inicial que profundiza en un campo escasamente abordado en nuestro medio acerca del conocimiento y difusión de los trabajos de herrería en el marco del patrimonio arquitectónico y artístico uruguayo, proporcionando información útil a la academia, las instituciones vinculadas a la valoración y conservación patrimonial y el público general. Notas [i] Proyecto concursado y financiado en la modalidad Investigación y Desarrollo (I+D), Comisión Sectorial de Investigación científica (CSIC), Universidad de la República, a realizarse entre marzo de 2018 y marzo de 2020, por un equipo interdisciplinario integrado por docentes e investigadores de las facultades de Arquitectura, Diseño y Urbanismo: Miriam Hojman, Valentina Marchese y Tatiana Rimbaud (Instituto de Historia), Gianella Mussio, Leticia Olivera, Carola Romay y Verónica Ulfe (Instituto de Tecnologías); de la Facultad de Humanidades y Ciencias de la Educación: Ernesto Beretta (Instituto de Ciencias Históricas-Historia del Arte); y de la Facultad de Ingeniería: Sofía Aguiar (Instituto de Ensayo de Materiales). El presente artículo fue elaborado por todos los integrantes del equipo.

The maturation process of beef improves meat quality. Several bio-physical-chemical changes occur during ageing. Often, they emerge macroscopically as variations in the mechanical properties of the tissue. Most of the actual testing methods are destructive. Therefore, the number of tested samples is limited. Elastography was born as a medical imaging modality to estimate noninvasively the elasticity of soft tissues. Thus, its application to monitor ageing could help to overcome some drawbacks of destructive methods. However, its use is minimum in industry. In this work, we study the feasibility of using surface wave elastography (SWE) to monitor beef ageing. We tested 25 samples for 21 consecutive days. The results show a decay close to 50% in the shear elasticity of all samples. In addition, the rate of decay show that the elasticity reduction is greater in the first days for most samples. These results are consistent with previous knowledge in this area, which encourages further research to improve the method and increase its performance and reliability.

The shear elastic modulus is one of the most important parameters to characterize the mechanical behavior of soft tissues. In biomechanics, ultrasound elastography is the gold standard for measuring and mapping it locally in skeletal muscle in vivo. However, their applications are limited to the laboratory or clinic. Thus, low-frequency elastography methods have recently emerged as a novel alternative to ultrasound elastography. Avoiding the use of high frequencies, these methods allow obtaining a mean value of bulk shear elasticity. However, they are frequently susceptible to diffraction, guided waves, and near field effects, which introduces biases in the estimates. The goal of this work is to test the performance of the non-ultrasound surface wave elastography (NU-SWE), which is portable and is based on new algorithms designed to correct the incidence of such effects. Thus, we show its first application to muscle biomechanics. We performed two experiments to assess the relationships of muscle shear elasticity versus joint torque (experiment 1) and the electromyographic activity level (experiment 2). Our results were comparable regarding previous works using the reference ultrasonic methods. Thus, the NU-SWE showed its potentiality to get wide the biomechanical applications of elastography in many areas of health and sports sciences.

This article summarizes some aspects of the project "Iron and bronze. Criteria for the valuation and conservation of ornamental metalworks in the architectural heritage of Uruguay", whose objective is to establish the heritage attributes of the metallic ornamental elements associated with facades of the national architectural heritage and contribute to their dissemination, enhancement, and conservation. Throughout the research, socio-cultural, artistic, formal, and technical aspects are addressed, and finally, those related to the deterioration of these elements and the guidelines for their preservation and restoration.The methodology is based on the study of primary sources, published and unpublished, on the revision of specialized bibliography and on the site work on a representative sample of metallic ornamental elements applied to the facades of Montevideo architecture. A total of 250 buildings were surveyed, corresponding to the different periods that we distinguished in the evolution of the local ornamental metalwork between the end of the 18th century and the middle of the 20th century. It is an initial contribution that delves into a field that is scarcely studied in our environment about the knowledge and dissemination of metalwork in the context of the Uruguayan architectural and artistic heritage, providing useful information to the academy, the institutions linked to the valuation and heritage conservation and the general public.

Soft biological tissue elasticity is a parameter whose reliable measure is relevant to many applications in fields as diverse as medicine and the agrifood industry. The ultrasonic elastography methods are often unviable to be applied to provide such solutions. In this way, the surface wave elastography (SWE) appears as a viable alternative, due its low cost, easy to use, non-invasive-destructive character as well as its ability to provide in vivo estimates. Previous studies have described a good correlation between the overall behavior of ultrasonic elastography and SWE, although the latter overestimates the elasticity values compared to the first. It has been suggested that this is due to the influence of certain physical effects related to the exclusive use of low frequency waves, as well as by characteristics of the experimental setup and/or medium. In this work we confirm the influence of such effects and discuss different strategies to make independent the estimations thereof. This allows achieving a good agreement between the ultrasonic reference method and SWE. Thus, SWE becomes a reliable method to estimate soft biological tissue elasticity.

In dynamic elastography, the goal is to estimate the Young's modulus from audio-frequency wave propagation in soft-tissues. Within this frequency range, the shear wavelength is centimeter-sized while the compressional wavelength is meter-sized. Thus, the experimental data are usually collected in the near-field of the source. Near-field effects have been widely studied for bulk wave propagation. However, the near- and transient-fields of surface and guided waves have received less attention. In this work, the transient surface displacement field in soft-solid elastic plates in vacuum is analyzed. Due to the high Poisson's ratio, mode conversion has special characteristics in soft-solids. They are analyzed through this work where it is shown that the transient-field over the surface can be interpreted by tracing a few reflections. The authors show the existence of a critical distance needed for the formation of Rayleigh-Lamb modes. Below this distance, only direct surface waves propagate without contribution from reflected waves. Thus, the dispersion curve differs from that predicted by Rayleigh-Lamb modes. Instead, the authors propose a model based on the interference of surface waves, which agree with the experimental data. In addition, the conditions needed in order to retrieve the shear wave phase velocity from the surface field are given.

Knowledge of muscle mechanical properties is important in clinical practice and biomechanical research. In usual clinical practice the muscle's Young modulus (Y) is qualitatively inferred through manual palpation and others valuation techniques of joint range. Although these methods are sensitive, they have predictable variations between different examiners, which reveals the need for methods capable of providing reliable quantitative values of muscular elasticity. Previous studies have shown that transient elastography (TE) is a useful method for assess locally and in vivo the Young modulus of muscle. In these works, experiments using TE were carried out on biceps brachii of healthy volunteers, testing the muscular elasticity changes under three load conditions: 0, 1 and 2 Kg. However, due to its high cost, this method is currently unavailable in many countries for standard clinical practice. In this work, taking into account the existing background with TE, we propose a low-cost method based on surface wave (SW) propagation for the in vivo assessment of the muscle's global mechanical properties. To validate the method, we repeated the experiments with TE, and compared the quantitative values and the general behavior exhibited by both methods. The results showed a good agreement between TE and SW methods, explaining the differences mainly by diffraction effects. We think that the in the current context, this method could be used widely in the rehabilitative and sports medicine field, both as a monitoring tool as well as research.