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Simulating nanoparticle transport in 3D geometries with MNM3D
No full textThe application of NP transport to real cases, such as the design of a field-scale injection or the prediction of the long term fate of nanoparticles (NPs) in the environment, requires the support of mathematical tools to effectively assess the expected NP mobility at the field scale. In general, micro- and nanoparticle transport in porous media is controlled by particle-particle and particle-porous media interactions, which are in turn affected by flow velocity and pore water chemistry. During the injection, a strong perturbation of the flow field is induced around the well, and the NP transport is mainly controlled by the consequent sharp variation of pore-water velocity. Conversely, when the injection is stopped, the particles are transported solely due to the natural flow, and the influence of groundwater geochemistry (ionic strength, IS, in particular) on the particle behaviour becomes predominant. Pore-water velocity and IS are therefore important parameters influencing particle transport in groundwater, and have to be taken into account by the numerical codes used to simulate NP transport. Several analytical and numerical tools have been developed in recent years to model the transport of colloidal particles in simplified geometry and boundary conditions. For instance, the numerical tool MNMs was developed by the authors of this work to simulate colloidal transport in 1D Cartesian and radial coordinates. Only few simulation tools are instead available for 3D colloid transport, and none of them implements direct correlations accounting for variations of groundwater IS and flow velocity. In this work a new modelling tool, MNM3D (Micro and Nanoparticle transport Model in 3D geometries), is proposed for the simulation of injection and transport of nanoparticle suspensions in generic complex scenarios. MNM3D implements a new formulation to account for the simultaneous dependency of the attachment and detachment kinetic coefficients on groundwater IS and velocity. The software was developed in the framework of the FP7 European research project NanoRem and can be used to predict the NP mobility at different stages of a nanoremediation application, both in the planning and design stages (i.e. support the design of the injection plan), and later to predict the long-term particle mobility after injection (i.e. support the monitoring, final fate of the injected particles). In this work MNM3D an integrated experimental-modelling procedure is used to assess and predict the nanoparticle transport in porous media at different spatial and time scales: laboratory tests are performed and interpreted using MNMs to characterize the nanoparticle mobility and derive the constitutive equations describing the suspension behavior in groundwater. MNM3D is then used to predict the NP transport at the field scale. The procedure is here applied to two practical cases: a 3D pilot scale injection of CARBO-IRON® in a large scale flume carried out at the VEGAS facilities in the framework of the NanoRem project; the long term fate of an hypothetical release of nanoparticles into the environment from a landfill is simulate
3D Faces reconstruction applied to some paintings of Leonardo da Vinci
No full textIn a previous article we have discussed a remarkable software which solves a difficult task, that of having a 3D facial reconstruction from a single 2D image. This software was developed by Jackson, Bulat, Argyriou and Tzimiropoulos at the University of Nottingham and Kingston University. We have also shown that the software can be applied to painted portraits of persons or to pictures of marble busts. Here we apply the software to a 3D reconstruction of some faces obtained from paintings of Leonardo da Vinci (La Gioconda, John the Baptiste, Bacchus and the Salvator Mundi). We discuss in particular the Salvator Mundi
Intra-Subject Consistency during Locomotion: Similarity in Shared and Subject-Specific Muscle Synergies
No full textHuman locomotion is a complex motor task. Previous research hypothesized that muscle synergies reflect the modular control of muscle groups operated by the Central Nervous System (CNS). Despite the high stride-to-stride variability characterizing human gait, most studies analyze only a few strides. This may be limiting, because the intra-subject variability of motor output is neglected. This gap could be filled by recording and analyzing many gait cycles during a single walking task. In this way, it can be investigated if CNS recruits the same muscle synergies consistently or if different strategies are adopted during the locomotion task. The aim of this work is to investigate the intra-subject consistency of muscle synergies during overground walking. Twelve young healthy volunteers were instructed to walk for 5 min at their natural pace. On the average, 181 ± 10 gait cycles were analyzed for each subject. Surface electromyography was recorded from 12 muscles of the dominant lower limb and the trunk. Gait cycles were grouped into subgroups containing 10 gait cycles each. The consistency of the muscle synergies extracted during the gait trial was assessed by measuring cosine similarity (CS) of muscle weights vectors, and zero-lag cross-correlation (CC) of activation signals. The average intra-subject CS and CC were 0.94 ± 0.10 and 0.96 ± 0.06, respectively. We found five synergies shared by all the subjects: high consistency values were found for these synergies (CS = 0.96 ± 0.05, CC = 0.97 ± 0.03). In addition, we found 10 subject-specific synergies. These synergies were less consistent (CS = 0.80 ± 0.20, CC = 0.89 ± 0.14). In conclusion, our results demonstrated that shared muscle synergies were highly consistent during walking. Subject-specific muscle synergies were also consistent, although to a lesser extent
Synchronous reluctance motor with concentrated windings for IE4 efficiency
No full textThis paper investigates the applicability of fractional-slot concentrated windings to Synchronous Reluctance Motors for industry applications. Tooth-wound winding arrangements are attractive for the industry due to their lower cost of manufacturing, but when associated to a synchronous reluctance rotor they tend to lower the output torque and power factor of the machine significantly, and to excite high values of torque ripple. The proposed analysis shows that after design optimization one synchronous reluctance machine with concentrated windings can reach the IE4 (super-premium) efficiency class within the same frame of a distributed-winding synchronous reluctance machine of the same size. Moreover, the paper demonstrates that the synchronous reluctance rotor must be purposely redesigned for the new stator, when passing from distributed to concentrated windings, for the sake of torque ripple mitigation. A step by step design procedure is provided, supported by finite-element analysis and experimental results
Gathering Process Data in Low Voltage Systems by Enhanced Event-Driven Metering
No full textEvent-driven metering is an emergent paradigm enabling significant data compression enhancement with respect to the conventional time domain metering techniques. This paper first discusses the representation of energy-based data in Low Voltage segments of Smart Grids by using a process-oriented approach, providing an original interpretation in terms of accumulated energy. This interpretation is used to construct an overall framework containing multiple options for representing energy-based data, encompassing uniform and non-uniform linear time finite elements. A specific representation of the information defined in the space of digital events is then presented under the established framework. An enhanced representation of energy-based data identified as digital events is introduced, leading to the formulation of the final Event-Based Data Gathering (EBDG) scheme. Dedicated tests are carried out on exemplificative data sets for residential customers, including a new challenging benchmark developed by using a fuzzy- controlled load for air conditioning. The results obtained validate the use of the EBDG scheme to mine the energy-varying processes occurring at the remote nodes of the distribution system. Finally, the approach leading to the EBDG scheme is discussed to show how it falls within the realm of BigData and to highlight how the EBDG results can be used to enable analytic accounting of the energy consumed in the processes occurring in a given time interval
A Model Predictive Control approach to micro-slip control of Automated Manual Transmission systems
No full textA novel design approach for space components: application to a multifunctional panel
No full textOne of the most challenging problems that engineers must face during the design phase of any single component of space systems is weight. The more is reduced, the less the launch will cost. Another critical aspect to consider is the overall dimensions of any object together with the coupling and compatibility with the surrounding parts. Via progressively integrating more functions into a single element, is it possible to optimize the final configuration of a complex object, addressing the multi-purpose role required for future applications. Although in the past this integration was not always possible, nowadays the emerging additive techniques are en-hancing the design freedom with novel solutions. In fact, the present trend in all industrial sectors is to introduce additive manufacturing, not only for rapid prototyping, but also for producing components to be used for real appli-cations. Due to safety reason, the usage of this production technique for space application is very limited, but several increasing test campaigns are rapidly rising its Technology Readiness Level (TRL). A novel concurrent design approach that integrates not only the thermal and structural performances, but also the technical feasibility, could be a great turning point for the project methodology. The purpose of this work is to cast some lights into the multidisciplinary design of the next generation of space components introducing these novel aspects. In as much as 3D printing is the future production trend, Selective Laser Melting (SLM) technology has been adopted for the analysis presented. The case study presented in this paper outline a new design method applied for a multifunctional panel to be used as cold plate as well as structural panel, able to cope with the hostile ambient conditions of space missions. The primary function of the proposed part is to withstand the loads, from the launch to the operative phases and, instead of having a dedicated and separated loop for thermal regulation, the panel is designed to internally incorporate the working fluid
RUST REMIX. Architecture: Pittsburgh versus Detroit
No full textTra la città dell'acciaio, Pittsburgh e quella iconica dell'auto, Detroit, nella Rust-Belt americana, progetti con gradienti diversi di intervento disegnano il cambiamento. Architetture che determinano nuove spazialità, usi e forme, che comportano in prevalenza riplasmazioni di scocche strutturali e di materiali e raccontano un contesto segnato dalla crisi della post-industrializzazione. Narrazione e riscrittura di alcuni casi studio offrono una riflessione sul ruolo che il progetto e gli architetti possono oggi assumere nella ridefinizione di un sistema del live, work and play diversamente produttivo. Projects with different levels of intervention are producing changes in the steel city of Pittsburgh and the iconic motor city of Detroit, two of America's Rust-Belt cities. Architecture is determining new spatialities, uses and forms, mainly by engaging the remodeling of structural skeletons and architecture materials, found assets in a context marked by the post-industrial crisis. Through the narration of several case studies, it is possible to reflect on the current role played by projects and architects in redefining a different live, work and play production system
