Development of an experimental test rig for cogeneration based on a Stirling engine and a biofuel burner

A system consisting of a last-generation Stirling engine (SE) and a fuel burner for distributed power generation has been developed and experimentally investigated. The heat generated by the combustion of two liquid fuels, a standard Diesel fuel and a rapeseed oil, is used as a heat source for the SE, that converts part of the thermal energy into mechanical and then electric energy. The hot head of the SE is kept in direct contact with the flame generated by the burner. The burner operating parameters, designed for Diesel fuel, were changed to make it possible to burn vegetable oils, not suitable for internal combustion engines. The possibility of adopting different configurations of the combustion chamber was taken into account to increase the system efficiency. The preliminary configurations adopted allowed to operate this integrated system, obtaining an electric power up to 4.4 kW(el)with a net efficiency of 11.6%

Bioengineered Wound Healing Skin Models: The Role of Immune Response and Endogenous ECM to Fully Replicate the Dynamic of Scar Tissue Formation In Vitro

The healing of deep skin wounds is a complex phenomenon evolving according with a fine spatiotemporal regulation of different biological events (hemostasis, inflammation, proliferation, remodeling). Due to the spontaneous evolution of damaged human dermis toward a fibrotic scar, the treatment of deep wounds still represents a clinical concern. Bioengineered full-thickness skin models may play a crucial role in this direction by providing a deep understanding of the process that leads to the formation of fibrotic scars. This will allow (i) to identify new drugs and targets/biomarkers, (ii) to test new therapeutic approaches, and (iii) to develop more accurate in silico models, with the final aim to guide the closure process toward a scar-free closure and, in a more general sense, (iv) to understand the mechanisms involved in the intrinsic and extrinsic aging of the skin. In this work, the complex dynamic of events underlaying the closure of deep skin wound is presented and the engineered models that aim at replicating such complex phenomenon are reviewed. Despite the complexity of the cellular and extracellular events occurring during the skin wound healing the gold standard assay used to replicate such a process is still represented by planar in vitro models that have been largely used to identify the key factors regulating the involved cellular processes. However, the lack of the main constituents of the extracellular matrix (ECM) makes these over-simplistic 2D models unable to predict the complexity of the closure process. Three-dimensional bioengineered models, which aim at recreating the closure dynamics of the human dermis by using exogenous biomaterials, have been developed to fill such a gap. Although interesting mechanistic effects have been figured out, the effect of the inflammatory response on the ECM remodelling is not replicated yet. We discuss how more faithful wound healing models can be obtained by creating immunocompetent 3D dermis models featuring an endogenous ECM

Preliminary activity on the pyrolysis of a plastic based solid recovered fuel

Plastic is a versatile, lightweight, resistant, and inexpensive material, and an increase of its global demand has been observed in the last years (from 299 milion tonnes in 2013 to 348 in 2017) [1], with the dominant role played by the packaging sector, which absorbs almost 40% of the overall production. Management of post–consumer plastic packaging waste poses a serious environmental problem, and a number of strategies have been devised to reuse/recover these materials, mainly with the aim of recovering useful materials and avoiding landfilling. Among these strategies, pyrolysis can play a significant role for recovering useful products and energy from the post–selection mixed packaging waste, that is not amenable to other uses [1]. A large amount of studies has been developed to assess the possibility to convert waste plastic to oil by pyrolysis processes [1] either catalytic or non catalytic. Nevertheless, only a limited numbers of papers refer to the use of real plastic waste rather than simulated mixtures [2] even if the performances obtained are strongly influenced by the feedstock characteristics. Please click Additional Files below to see the full abstract

Acumulaciones de detritos leñosos en un cauce de montaña de Tierra del Fuego: análisis de la movilidad y de los efectos hidromorfológicos

This work reports on the geomorphic role of large wood pieces and jams in a third order mountain stream located in Southern Tierra del Fuego (Argentina), and draining an old-growth nothofagus forested basin not influenced by beaver damming activity. Even if the in-stream number of wood pieces (2,300) is comparable to that observed in other climatic areas, the slow growth of the nothofagus forest causes a lower wood abundance in terms of volumetric load (121 m3 ha–1). Due to the relatively small dimensions of the large wood pieces located inside bankfull edges (83% of the total surveyed pieces), almost the 70% of them demonstrated to have been transported by runoff and 6% derived from bank erosion or landslides. Wood jams exert a significant influence on the channel morphology, being responsible for the creation of 30% of pools. The geomorphic influence of LW jams is also exerted by a considerable sediment storing capacity (about 1,750 m3). The LW-forced pool volume is strongly and positively correlated to the height of the LW jam. The results confirm that dead wood pieces, especially when organized in jams, play an important geomorphic role also in sub-Antarctic streams. The amount of large wood pieces quantified in the study site represents reference values for the assessment of the geomorphic effects of beaver activity in other Tierra del Fuego streams

LW jams in a mountain stream of Tierra del Fuego: piece movement and hydro-morphological effects analysis

This work reports on the geomorphic role of large wood pieces and jams in a third order mountain stream located in Southern Tierra del Fuego (Argentina), and draining an old-growth nothofagus forested basin not influenced by beaver damming activity. Even if the in-stream number of wood pieces (2,300) is comparable to that observed in other climatic areas, the slow growth of the nothofagus forest causes a lower wood abundance in terms of volumetric load (121 m3 ha–1). Due to the relatively small dimensions of the large wood pieces located inside bankfull edges (83% of the total surveyed pieces), almost the 70% of them demonstrated to have been transported by runoff and 6% derived from bank erosion or landslides. Wood jams exert a significant influence on the channel morphology, being responsible for the creation of 30% of pools. The geomorphic influence of LW jams is also exerted by a considerable sediment storing capacity (about 1,750 m3). The LW-forced pool volume is strongly and positively correlated to the height of the LW jam. The results confirm that dead wood pieces, especially when organized in jams, play an important geomorphic role also in sub-Antarctic streams. The amount of large wood pieces quantified in the study site represents reference values for the assessment of the geomorphic effects of beaver activity in other Tierra del Fuego streams.Se analizaron los volúmenes de material leñoso y las tipologías de acumulaciones observadas en el cauce del torrente Buena Esperanza, uno de los pocos cursos de agua de Tierra del Fuego (Argentina) no afectado por la presencia de castores. Aunque el número de piezas leñosas medidas en el cauce (2.300 elementos) fue comparable a lo reportado en otras áreas geográfica-climáticas, se estimó una menor abundancia en términos de volumen total de detritos leñosos (121 m3 ha–1) debido al lento crecimiento del bosque de Nothofagus spp. en estas latitudes. El 83% de los detritos leñosos se localizó dentro del canal activo, del cual el 75% presentó señales de haber sido transportado por la corriente, el 6% se asoció a aportes laterales al torrente por deslizamientos y erosión de márgenes, y el resto a residuos de cosecha. Las dimensiones relativamente pequeñas del material leñoso se reflejaron en las tipologías de acumulaciones de troncos individualizadas, prevaleciendo las de tipo mixtas (63%). Se estimó que las acumulaciones mixtas influyen en la morfología del cauce, siendo responsables de la retención de un volumen de 1.750 m3 de sedimentos depositados y de la creación del 30% de las pozas. Finalmente, se identificó una correlación positiva significativa entre los volúmenes de las pozas y la altura de las acumulaciones. Los resultados destacan la importancia hidromorfológica de las acumulaciones leñosas, y representan una referencia para la evaluación de los impactos determinados por las colonias de castores en otros ríos de Tierra del Fuego.Facultad de Ingenierí

Computational Modelling of Tissue-Engineered Cartilage Constructs

Cartilage is a fundamental tissue to ensure proper motion between bones and damping of mechanical loads. This tissue often suffers damage and has limited healing capacity due to its avascularity. In order to replace surgery and replacement of joints by metal implants, tissue engineered cartilage is seen as an attractive alternative. These tissues are obtained by seeding chondrocytes or mesenchymal stem cells in scaffolds and are given certain stimuli to improve establishment of mechanical properties similar to the native cartilage. However, tissues with ideal mechanical properties were not obtained yet. Computational models of tissue engineered cartilage growth and remodelling are invaluable to interpret and predict the effects of experimental designs. The current model contribution in the field will be presented in this chapter, with a focus on the response to mechanical stimulation, and the development of fully coupled modelling approaches incorporating simultaneously solute transport and uptake, cell growth, production of extracellular matrix and remodelling of mechanical properties.publishe

240th ENMC workshop: the involvement of skeletal muscle stem cells in the pathology of muscular dystrophies 25 -27 January 2019, Hoofddorp, the Netherlands

Satellite cells are dysfunctional in several neuromuscular disorders. Some muscles are more susceptible than others to disease and ageing. In vitro and in vivo model systems have shed light on many of the processes involved. in satellite cell function and dysfunction, but the drawbacks of each model system must be considered. Skeletal muscle pathology in mouse models of neuromuscular disease are affected by genetic background. A single cell approach will be useful to identify dysfunction in subsets of cell populations

Influenza delle condizioni di processo sulla crescita di bio-ibridi tessutali

La rigenerazione ex-vivo di tessuti viventi è una area scientifica in rapido sviluppo con un potenziale alto impatto in larga scala in applicazioni biomediche. Il maggiore ostacolo alla produzione o rigenerazione di tessuti funzionali ed i loro utilizzo clinico, è legato alla limitata comprensione di come applicare in un processo automatizzato l’ influenza delle variabili di processo sui parametri metabolici e biosintetici. La moderna industria (chimica, farmaceutica, ecc..) è fondata sul fatto che le “unit operations” di cui è composto un processo, sono sistemi di cui si conosce perfettamente la variabilità degli outputs in funzione degli inputs, sia da un punto di vista teorico che applicativo. Tale risultato abilita i tecnici specializzati del settore, a progettare impianti di produzione ottimizzati e controllati in modo da standardizzare ed ottimizzare la produttività di un bene. L’ ingegneria tessutale può essere vista come una disciplina che si pone l’obiettivo di produrre tessuti funzionali. Per fare ciò è necessaria la comprensione e la modellazione dei fenomeni che regolano la biosintesi di tessuto da un punto di vista ingegneristico. Se si conosce come modellare tale processo è possibile da un lato, fare delle previsioni sul comportamento facendo variare le variabili, da un lato è possibile progettare sistemi (bioreattori), che guidano il fenomeno verso targets definiti dall’utente. La modellazione della crescita di un tessuto passa attraverso diverse discipline in quanto è proprio il sistema di partenza (bio-ibrido) ad essere un sistema complesso. Un bio-ibrido è composto da un materiale polimerico poroso saturo di un fase fluida in cui sono presenti cellule e soluti macromolecolari. Durante un processo rigenerazione il bio-ibrido è sottoposto a stimoli in termini di sollecitazione meccaniche, fluidodinamiche e chimiche. Tali sistemi vengono in genere modellati con la teoria multifasica la quale riesce accoppiare in un singolo modello tre fenomenologie mutuamente accoppiate in questi sistemi: Meccanica, Fluidodinamica, Trasporto. Nell’ ottica di volere comprendere come utilizzare questo modello per progettare processi di rigenerazione tessutale verranno indagati due aspetti: o Trasporto molecolare attivato meccanicamente: in questa fase verrà mostrato come il trasporto in un sistema gel-like sia dipendente dalle sollecitazione meccaniche. Questo aspetto è di fondamentale importanza in quanto la concentrazione di fattoti di crescita e di prodotti di scarto del metabolismo, influenza direttamente la bio-sintesi cellulare la quale quindi risulta essere dipendente a sua volta dalle stimolazioni esterne. o Variazione temporale delle proprietà meccaniche e di trasporto di bio-ibridi cellulari: in questa fase verrà mostrato come la teoria multi-fasica è in grado di calcolare alcune grandezze fondamentali che altrimenti risulterebbero di difficile determinazione. Si mostrerà come le grandezze a cui si fa riferimento per progettare processi di rigenerazione, in realtà variano durante il processo stesso. Ciò che si vuole mettere in luce è che laddove si riesca a trovare una zona di ottimo per la produzione di un determinato tessuto, in realtà questo punto di lavoro è processo-dipendente e va quindi aggiornato opportunamente