Computational fluid dynamic simulations of image-based stented coronary bifurcation models

One of the relevant phenomenon associated with in-stent restenosis in coronary arteries is an altered haemodynamics in the stented region. Computational fluid dynamics (CFD) offers the possibility to investigate the haemodynamics at a level of detail not always accessible within experimental techniques. CFD can quantify and correlate the local haemodynamics structures which might lead to in-stent restenosis. The aim of this work is to study the fluid dynamics of realistic stented coronary artery models which replicate the complete clinical procedure of stent implantation. Two cases of pathologic left anterior descending coronary arteries with their bifurcations are reconstructed from computed tomography angiography and conventional coronary angiography images. Results of wall shear stress and relative residence time show that the wall regions more prone to the risk of restenosis are located next to stent struts, to the bifurcations and to the stent overlapping zone for both investigated cases. Considering a bulk flow analysis, helical flow structures are generated by the curvature of the zone upstream from the stent and by the bifurcation regions. Helical recirculating microstructures are also visible downstream from the stent struts. This study demonstrates the feasibility to virtually investigate the haemodynamics of patient-specific coronary bifurcation geometries.     

Junctionless MOSFETs with laterally graded-doping channel for analog/RF applications

In this paper, we propose a laterally graded-channel pseudo-junctionless (GPJL) MOSFET for analog/RF applications. We examine the dynamical performance of GPJL MOSFET and compare it with the common junctionless (JL) MOSFET architecture using a 2-D full-band electron Monte Carlo simulator (MC) with quantum correction. Our results indicate that the GPJL MOSFET outperforms the conventional JL MOSFET, yielding higher values of drain current (I _ds), transconductance (g _m), and cutoff frequency (f _t). Further, the emerging electric field and velocity distributions, as a consequence of the channel engineering introduced by the GPJL MOSFET, result in lower output conductance (g _ds) and higher early voltage (V _ea). The preeminence of the GPJL transistor over the JL transistor is further illustrated by showing improvements on the intrinsic voltage gain (A _vo) in the subthreshold regime, to as high as 61 %. These results indicate that our proposed GPJL MOSFET yields improvement in the analog/RF performance metrics as compared to JL MOSFETs.     

A boundary knot method for harmonic elastic and viscoelastic problems using single-domain approach

The boundary knot method is a promising meshfree, integration-free, boundary-type technique for the solution of partial differential equations. It looks for an approximation of the solution in the linear span of a set of specialized radial basis functions that satisfy the governing equation of the problem. The boundary conditions are taken into account through the collocation technique. The specialized radial basis function for harmonic elastic and viscoelastic problems is derived, and a boundary knot method for the solution of these problems is proposed. The completeness issue regarding the proposed set of radial basis functions is discussed, and a formal proof of incompleteness for the circular ring problem is presented. In order to address the numerical performance of the proposed method, some numerical examples considering simple and complex domains are solved.     

Traceability of electrical quantities obtained by sampling

The substitution of the traditional analogic measurement and processing techniques with sampling methods is a trend in modern metrology. Many commercial instruments perform this determination by means of their internal firmware. An analysis is necessary when sampling instruments are employed within a laboratory, for the determination of one or more quantities. However, this analysis is possible only under some specific circumstances, where both the characteristics of the samples and the processing algorithms have to be known.The paper will consider the samples as input for the determination of given quantities and the methods to evaluate the uncertainty of the results from the uncertainty of the samples and their correlation. The example is derived by the uncertainty evaluation of the INRIM system for the precision measurement of the power, where the determination of the accuracy has been accomplished both by an almost analytical approach followed by a numerical evaluation.     

Fiber diffraction study of spicules from marine sponges

A synchrotron radiation fiber diffraction structural study of the axial filament of siliceous spicules from two species of marine sponges (the Demosponge Geodia cydonium and the Hexactinellid Scolymastra joubini) was carried out. The sharpness of the spots in the diffraction patterns indicated that the protein units in the filament of both samples were highly organized. A possible explanation is that the arrangement of the protein units is similar to that of the pores in highly ordered siliceous mesoporous materials. Nevertheless, the diffraction patterns are quite different for the two types of spicules. The pattern of G. cydonium is consistent with a regular 2D hexagonal lattice of protein units in the direction perpendicular to the spicule axis, with a repeating distance of 5.8 nm; the units are linked to form fibers along the axis. The pattern of S. joubini indicates the presence of two different 2D lattices in which the repeating protein units are inclined by +50 degrees and -50 degrees with respect to the elongation axis; the distance between the units increases to 8.4 nm. This 2D model is consistent with hexagonal packing of spirally oriented cylindrical protein units elongated along the filament axis.     

Emerging specializations,competences and firms' proximity in digital industries: The case of London

In order to overcome the limitations of defining industrial specializations in digital industries through SIC codes, this paper suggests measuring the specializations and competences of these industries on the basis of the degree of digital technologies present in the products and services supplied. Metadata from CrunchBase are employed, as proxies of firms' specializations and competences which are defined as the fields of activity in which firms are involved. Applying a network analysis, these specializations and competences are linked to the recognition of emerging digital technologies and the strongest combinations of products and services. We tested the proposed methodology on London, a leading centre for the digital economy.     

Fire Performance Assessment of a Fiber Reinforced Polymer Wall Panel Used in a Single Family Dwelling

This paper describes a fire performance assessment of a sandwich panel selected as the primary material in a high-performance house developed for the 2013 China Solar Decathlon competition. The sandwich panel has fiber reinforced polymer skins and a foam plastic core. Evaluation of fire performance showed that the selected panel would not comply with U.S. building code requirements for a single-family dwelling without additional protection. However, the use of an intumescent fire protective coating, coupled with the installation of a residential fire sprinkler system, is shown to be effective in meeting the intent of the fire and life safety requirements of the International Residential Code. Fire testing shows that the application of an intumescent fire protective coating to the panels significantly decreases the heat release rate, the smoke production characteristics, and the extent of flame spread on the panels.     

Integrated Approach for Supporting Sustainable Water Resources Management of Irrigation Based on the WEFN Framework

Irrigated agriculture plays a vital role for the socio-economic development of the Mediterranean area, although it has significant impacts on both water and energy resources. Therefore, in a context in which water resources are also experiencing increasing pressures, there is an urgent need for supporting their sustainable management. This may be an extremely challenging task, especially at the local scale, due to the several interconnected dynamics affecting the state of a complex irrigation system. In fact, multiple actors are involved in decision-making processes, and the use of natural resources (and their mutual interactions) strongly depends on their behaviors, which affect the system as a whole. In this context, the present study proposes an integrated methodology, based on the Water Energy Food Nexus (WEFN), specifically focused on the sustainable management of water resources for irrigation. Firstly, a model based on Causal Loop Diagrams (CLD) is developed in order to get a deep insight into the key dynamics behind a complex irrigation system. Secondly, three indices based on the “footprint” concept are identified, in order to synthesize such dynamics. The integration of these two approaches support investigating the whole system and, particularly, understanding the influence of multiple decisional actors on it, as well as the role of a set of key drivers and constraints. This might also allow drawing some relevant conclusions, useful for supporting effective decisions oriented to a sustainable water resources management. Specific reference is made to a case study, the Capitanata irrigation system, located in the Southern Italy.