DEVELOPMENT OF A TRIAXIAL FORCE PLATFORM FOR THE MEASUREMENT OF FORCE AT A BICYCLE PEDAL

The main purpose of this work is to present the methodology used to develop a triaxial force platform for the use at a pedal bicycle; this platform is based on the flexion of beams where strain gages are bonded for the measurements of force components FX, FY and FZ, as well as the force moments MX and MY. The theoretical analysis of this force platform was realized by the Finite Element method, with the simulation of 384 combinations of static loads (force and moments) at different directions. Deformation data numerically obtained is related to the position were sensors will be placed. Output signals obtained were numerically organized and graphically analyzed, in order to show the mathematical relation between force and strain, which is used to generate a "calibration matrix", free of mechanical coupling which usually appears in multiaxis systems. At last, a test was made, simulating an input load, and the output signal obtained was practically equal

Proyectar desde la imagen: la fotografía como instrumento creador de atmósferas construidas en la obra de Druot, Lacaton y Vassal

Lacaton & Vassal, in collaboration with Frédéric Druot were commissioned to upgrade 1960s and 1970s residential high rise developments in the banlieues of Paris. Based on the ‘never demolishing, subtracting or replacing things, but always adding, transforming and utilising them’ premise, the authors’ used a threestep procedure in which photography played a major role. The process starts with some images taken by photographer Julius Shulman in the Case Study House #22 by Pierre Koenig. The pictures evoke a familiar collective imaginary for architects, in which models and furniture are carefully arranged to create an atmosphere for the extraordinary series of US post war houses. These pictures from another time and place are dreams turned into an argument to justify the decision not to demolish the residential buildings. In a second stage Californian atmospheres are overlapped with the reality on which they must act. In a series of assemblages Shulman´s photographs interact with the reality of the vertical blocks, revealing the possibility of creating a new space, a gallery that extends the interior of the dwellings. Unattractive facades are replaced by glass from floor to ceiling, filling the rooms up with light and incorporating, as in the case of the house by Koenig, a panoramic view of the surrounding landscape. Photography appears again when the action has to be documented. The materialization of Tour Bois le Prêtre was exhibited in Frankfurt. The exhibition included photographs of the transformed interiors printed at full size and combined with domestic pieces of furniture, in order to create a three dimensional corner for visitors to experience by themselves the spatial qualities of the project. This project thus stands as a clear example that the relationship between photography and architecture provides the possibility of a new creative process. A way to design in which both disciplines continually get feedback from each other, obtaining results that were unforeseeable before this union.Lacaton y Vassal, en colaboración con Frédéric Druot, recibieron el encargo de acondicionar conjuntos de vivienda colectiva de las décadas de 1960 y 1970. Partiendo desde la premisa de ‘no derribar nunca, no restar ni reemplazar nunca, sino añadir, transformar y reutilizar siempre’, el equipo empleó un procedimiento en tres fases en el que la fotografía jugó un papel capital. El proceso arranca con las imágenes tomadas por el fotógrafo Julius Shulman en la Case Study House #22 de Pierre Koenig. Las fotografías evocan en los arquitectos un imaginario conocido, en el que los modelos y el mobiliario son cuidadosamente dispuestos para ambientar la extraordinaria serie de viviendas unifamiliares de postguerra estadounidenses. Estas fotografías de otro tiempo y lugar son ensoñaciones convertidas en argumento para justificar la decisión de no demoler los edificios residenciales. En un segundo momento las atmósferas californianas se superponen a la realidad sobre la que deben actuar. En una serie de montajes las fotografías de Shulman interactúan con la realidad de los bloques verticales, desvelando la posibilidad de creación de un nuevo espacio, una galería que amplía el interior de las viviendas. Las fachadas poco atractivas son sustituidas por vidrios de suelo a techo, llenando las estancias de luz e incorporando, como en el caso de la vivienda de Koenig, una visión panorámica del paisaje circundante. Las fotografías vuelven a aparecer al documentar la actuación. La materialización de Tour Bois le Prêtre se expuso en Frankfurt. La muestra incluía fotografías de los interiores transformados impresas a tamaño real y combinadas con mobiliario doméstico, creando un rincón con profundidad para que el visitante experimentara por sí mismo las cualidades espaciales del proyecto. Este proyecto se erige por tanto como claro ejemplo de que la relación entre la fotografía y la arquitectura proporciona la posibilidad de un proceso creativo nuevo. Una forma de proyectar en el que ambas disciplinas se retroalimentan continuamente obteniendo resultados no previsibles antes de esa unión

Controlled drug delivery systems for cancer based on mesoporous silica nanoparticles

Abstract: The implementation of nanotechnology in medicine has opened new research horizons particularly in the field of therapeutic delivery. Mesoporous silica particles have emerged as biocompatible drug delivery systems with an enormous potential in the treatment of cancer among many other pathologies. In this review, we focus on the unique properties of these particles as chemotherapy delivery carriers. Here, we summarize the general characteristics of these nanomaterials ? including their physicochemical properties and customizable surfaces ? different stimuli that can be used to trigger targeted drug release, biocompatibility and finally, the drawbacks of these types of nanomaterials, highlighting some of the most important features of mesoporous silica nanoparticles in drug delivery.This work has been supported by the Spanish MINECO and European Union FEDER Funds under Project Ref. PI16/00496 (AES 2016), CTM 2017-84050-R, MAT 2015-69508-P, NanoBioApp Network (MINECO-17-MAT2016-81955-REDT), Xunta de Galicia (Centro Singular de Investigación de Galicia - Accreditation 2016-2019 and EM2014/035), European Union (European Regional Development Fund-ERDF) and IDIVAL INNVAL15/15 and INNVAL17/11

Modal analysis of the lysozyme protein considering all-atom and coarse-grained finite element models

Proteins are the fundamental entities of several organic activities. They are essential for a broad range of tasks in a way that their shapes and folding processes are crucial to achieving proper biological functions. Low-frequency modes, generally associated with collective movements at terahertz (THz) and sub-terahertz frequencies, have been appointed as critical for the conformational processes of many proteins. Dynamic simulations, such as molecular dynamics, are vastly applied by biochemical researchers in this field. However, in the last years, proposals that define the protein as a simplified elastic macrostructure have shown appealing results when dealing with this type of problem. In this context, modal analysis based on different modelization techniques, i.e., considering both an all-atom (AA) and coarse-grained (CG) representation, is proposed to analyze the hen egg-white lysozyme. This work presents new considerations and conclusions compared to previous analyses. Experimental values for the B-factor, considering all the heavy atoms or only one representative point per amino acid, are used to evaluate the validity of the numerical solutions. In general terms, this comparison allows the assessment of the regional flexibility of the protein. Besides, the low computational requirements make this approach a quick method to extract the protein’s dynamic properties under scrutiny

Damage process in glass fiber reinforced polymer specimens using acoustic emission technique with low frequency acquisition

The damage process in fiber-reinforced polymers (FRP) has been the subject of continuous studies in recent decades using different approaches. In particular, the acoustic emission technique has been proved to be a powerful tool in the monitoring of structures of this type of material due to the large acoustic activity captured when this material is loaded to rupture. The present work explores several indexes that were calculated from the experimental recording of acoustic emission signals, and their efficiency in describing the failure process in structures. One of these indexes, called c value, is originally proposed, and its sensibility it is compared with other classical parameters that are usually employed in the Acoustic Emission analysis. A 3-point bending test has been performed on a glass fiber reinforced polymer plate. Our own methodology was proposed to identify AE signals in semi-automatic manner. This methodology also allowed a faster analysis of the global parameters during the process data of the AE test. The global parameter evolution obtained from the acoustic emission data during the damage process could be considered as precursors of the more meaningful event and as an aid to understand in which way the structure is going to the collapse

Numerical simulation of the road bus structure submitted a offset frontal impact against a rigid wall

Neste trabalho se apresenta um estudo paramétrico do impacto semifrontal em um ônibus, no qual se avalia independentemente a influência de cada variável envolvida neste tipo acidente. O cenário de impacto semifrontal é sem dúvida um dos mais severos acidentes envolvendo ônibus, pois parte da lateral do ônibus é totalmente danificada, podendo deixar um elevado número de vítimas. A simulação numérica utiliza um modelo de análise explícita formado por elementos de vigas que utiliza uma lei constitutiva elasto‐plástica, a qual leva em conta a influência da taxa de deformação. Com este modelo se realiza um estudo paramétrico das variáveis globais que permitem caracterizar este tipo de cenário. Também são avaliados de forma qualitativa acidentes deste tipo acontecidos nas estradas brasileiras. A discussão dos resultados é finalmente apresentada e serve como um primeiro passo na busca de melhorias a serem introduzidas nas estruturas dos ônibus, objetivando minimizar os danos.This paper presents a parametric study of the offset frontal impact on a bus, in which is assessed independently an influence of each variable involved in this accident type. The scenario of offset frontal impact is surely one of the most severe accidents involving buses, once the same has part of your lateral totally damaged and can leave a large number of victims. The numerical simulation model uses an explicit analysis formed by beams elements which uses elastic‐plastic constitutive law, which takes into account the influence of strain rate. With this model a parametric study of global variables that can characterize this type of scenario is realized. Also are evaluated qualitatively real accidents happened on Brazilian roads. The discussion is finally presented, and serves as a first step in the search for improvements to be made to the structures of the bus, aiming to minimize the damage.Peer Reviewe

Crack path estimation in the shot-earth 772 by a discrete element method

In the present paper, the fracture behaviour of the shot-earth 772, in terms of crack path, is numerically investigated. To such an aim, a version of the lattice discrete element method is used to numerically simulate fracture toughness testing performed, on the shot-earth 772, by employing the Modified Two-Parameter model. A comparison between the numerical crack path and the experimental ones is performed, highlighting as the lattice discrete element method is able to capture the kinked crack shape, typical of quasi-brittle material

Analysis of Acoustic Emission Activity during Progressive Failure in Heterogeneous Materials: Experimental and Numerical Investigation

This work focuses on an experimental and numerical investigation into monitoring damage in a cube-shaped concrete specimen under compression. Experimental monitoring uses acoustic emission (AE) signals acquired by two independent measurement apparatuses, and the same damage process is numerically simulated with the lattice discrete element method (LDEM). The results from the experiment and simulation are then compared in terms of their failure load, final configurations, and the evolution of global parameters based on AE signals, such as the b-value coefficient and the natural time approach. It is concluded that the results from the AE analysis present a significant sensitivity to the characteristics of the acquisition systems. However, natural time methods are more robust for determining such differences, indicating the same general tendency for all three data sets

Long-Range Correlations and Natural Time Series Analyses from Acoustic Emission Signals

This work focuses on analyzing acoustic emission (AE) signals as a means to predict failure in structures. There are two main approaches that are considered: (i) long-range correlation analysis using both the Hurst (H) and the detrended fluctuation analysis (DFA) exponents, and (ii) natural time domain (NT) analysis. These methodologies are applied to the data that were collected from two application examples: a glass fiber-reinforced polymeric plate and a spaghetti bridge model, where both structures were subjected to increasing loads until collapse. A traditional (AE) signal analysis was also performed to reference the study of the other methods. The results indicate that the proposed methods yield reliable indication of failure in the studied structures

Design of Polymeric and Biocompatible Delivery Systems by Dissolving Mesoporous Silica Templates

There are many nanoencapsulation systems available today. Among all these, mesoporous silica particles (MSPs) have received great attention in the last few years. Their large surface-to-volume ratio, biocompatibility, and versatility allow the encapsulation of a wide variety of drugs inside their pores. However, their chemical instability in biological fluids is a handicap to program the precise release of the therapeutic compounds. Taking advantage of the dissolving capacity of silica, in this study, we generate hollow capsules using MSPs as transitory sacrificial templates. We show how, upon MSP coating with different polyelectrolytes or proteins, fully customized hollow shells can be produced. These capsules are biocompatible, flexible, and biodegradable, and can be decorated with nanoparticles or carbon nanotubes to endow the systems with supplementary intrinsic properties. We also fill the capsules with a fluorescent dye to demonstrate intracellular compound release. Finally, we document how fluorescent polymeric capsules are engulfed by cells, releasing their encapsulated agent during the first 96 h. In summary, here, we describe how to assemble a highly versatile encapsulation structure based on silica mesoporous cores that are completely removed from the final polymeric capsule system. These drug encapsulation systems are highly customizable and have great versatility as they can be made using silica cores of different sizes and multiple coatings. This provides capsules with unique programmable attributes that are fully customizable according to the specific needs of each disease or target tissue for the development of nanocarriers in personalized medicine.This research was funded by ISCIII Projects ref. PI19/00349, DTS19/00033, co-funded by ERDF/ESF, “Investing in your future”; and MICINN Projects ref. CTM2017-84050-R, Xunta de Galicia (Centro Singular de Investigación de Galicia-Accreditation 2016-2019 and EM2014/035), European Union FEDER Funds (European Regional Development Fund-ERDF), and IDIVAL for INNVAL19/18 and INNVAL20/13 and the technical support