Search results for "CONSTRUCTION"

The index of stable critical points

2002

Abstract In this paper we show that in dimension greater or equal than 3 the index of a stable critical point can be any integer. More concretely, given any k∈ Z and n⩾3 we construct a C ∞ vector field on R n with a unique critical point which is stable (in positive and negative time) and has index equal to k. This result extends previous ones on the index of stable critical points.

Using Taguchi method for the optimization of processing variables to prepare porous scaffolds by combined melt mixing/particulate leaching

2017

Synthetic biopolymers have made significant inroads into the development of devices for tissue regeneration. In this context, a challenge is the achievement of appropriate properties mimicking the natural extracellular matrix by fabricating scaffolds presenting mechanical properties, specific surface, porosity and pore interconnection adequate for the final application. This study involved a systematic procedure based on Taguchi method for parameters optimization of melt mixing/particulate leaching combined processes aiming to enhance the performance of the scaffolds. In particular, it was evaluated the effect of time and temperature of melt mixing of the poly(lactic acid) matrix with two w…

Koncepcje uznania w perspektywie pedagogiki ogólnej jako alternatywa wobec neoliberalnej wizji współczesnego świata

2018

The most important task facing an individual is the work on their own identity – it is a manifestation of self-realization and freedom of a modern man. Recognition as an intersubjective relationship between people is a condition of our identity. A community based on recognition relationships is an alternative to a neo-liberal social concept. Intersubjective relationships of recognition are formed, according to Honneth, in three spheres: in the sphere of intimate relations (family, people that are close to us, significant others), in the sphere of law and in the sphere of economy. We have three areas then, in which, in relations with others, we build our identity: family, law and economy wit…

A simple method to fabricate high-performance nanostructured WO3 photocatalysts with adjusted morphology in the presence of complexing agents

2017

[EN] The rich and complex chemistry of tungsten was employed to synthesize innovative WO3 nanoplatelets/nanosheets by simple anodization in acidic electrolytes containing different concentrations of complexing agents or ligands, namely F- and H2O2. The morphological and photoelectrochemical properties of these nanostructures were characterized. The best of these nanostructures generated stable photocurrent densities of ca. 1.8 mA cm(-2) at relatively low bias potentials (for WO3) of 0.7 V-Ag/AgCl under simulated solar irradiation, which can be attributed to a very high active surface area. This work demonstrates that the morphology and dimensions of these nanostructures, as well as their ph…

MODELIZACIÓN MEDIANTE CFD DE PARA EVALUAR LA VENTILACIÓN EN UN EDIFICIO ARQUEOLÓGICO, DATOS PRELIMINARES.

2016

[EN] The present study addresses the influences of wind flow structure, as an important factor responsible of material damage (erosion contributing) on “Casa di Diana” Mithraeum, a roman building (130 A.D.) sited on Ostia Antica (archaeological site, Rome – Italy), through the Computational Fluid Dynamics (CFD) simulations and direct measurements for its verification and validation (V&V). In this preliminary work, we present results relating to 3D reconstruction (geometry of the entire building) and the mesh importing on Fluent software. In general, the data check confirms, with ±10%, a good agreement (model) between the numerical solutions and direct measurements data by portable sensor. F…

Software Architectures for Human-Machine Interaction Using Natural Language

Il linguaggio naturale rappresenta un sistema di comunicazione a carattere inferenziale in opposizione ai sistemi di comunicazione a codice che non prevedono una forma di ragionamento intelligente da parte del ricevente, ma si basano sul riconoscimento di patterns dell'informazione. In un sistema di comunicazione di tipo inferenziale, infatti, si parte dal presupposto che il ricevente abbia una certa "intelligenza" e sia, quindi, capace di comprendere, elaborare ed inferire il contenuto informativo di una comunicazione attraverso ragionamenti su un background di conoscenze (come modelli di mondo e di linguaggio) condivisi sia dalla sorgente che dal destinatario. L'attività di ricerca, svolt…

A direct impedance tomography algorithm for locating small inhomogeneities

2003

Impedance tomography seeks to recover the electrical conductivity distribution inside a body from measurements of current flows and voltages on its surface. In its most general form impedance tomography is quite ill-posed, but when additional a-priori information is admitted the situation changes dramatically. In this paper we consider the case where the goal is to find a number of small objects (inhomogeneities) inside an otherwise known conductor. Taking advantage of the smallness of the inhomogeneities, we can use asymptotic analysis to design a direct (i.e., non-iterative) reconstruction algorithm for the determination of their locations. The viability of this direct approach is documen…

Efficient estimation of tuned liquid column damper inerter (TLCDI) parameters for seismic control of base‐isolated structures

2022

This paper presents an enhanced base-isolation (BI) system equipped with a novel passive control device composed of a tuned liquid damper and an inerter (TLCDI). With the aim of reducing the seismic response of BI systems, this contribution focuses on the design of the TLCDI providing analytical solutions for the optimal TLCDI parameters, easily implementable in the design phase. The effectiveness of the proposed approach in terms of seismic response reduction and computational gain is validated by comparison with classical numerical optimization techniques. The control performance of two different base-isolated TLCDI-controlled structures is assessed by employing real-ground motion records…

Low-Rate Reduced Complexity Image Compression using Directionlets

2006

The standard separable two-dimensional (2-D) wavelet transform (WT) has recently achieved a great success in image processing because it provides a sparse representation of smooth images. However, it fails to capture efficiently one-dimensional (1-D) discontinuities, like edges and contours, that are anisotropic and characterized by geometrical regularity along different directions. In our previous work, we proposed a construction of critically sampled perfect reconstruction anisotropic transform with directional vanishing moments (DVM) imposed in the corresponding basis functions, called directionlets. Here, we show that the computational complexity of our transform is comparable to the co…

Space-Frequency Quantization using Directionlets

2007

In our previous work we proposed a construction of critically sampled perfect reconstruction transforms with directional vanishing moments (DVMs) imposed in the corresponding basis functions along different directions, called directionlets. Here, we combine the directionlets with the space-frequency quantization (SFQ) image compression method, originally based on the standard two-dimensional (2-D) wavelet transform (WT). We show that our new compression method outperforms the standard SFQ as well as the state-of-the-art compression methods, like SPIHT and JPEG-2000, in terms of the quality of compressed images, especially in a low-rate compression regime. We also show that the order of comp…