Search results for "ingegneria"

Neural networks with non-uniform embedding and explicit validation phase to assess Granger causality

2015

A challenging problem when studying a dynamical system is to find the interdependencies among its individual components. Several algorithms have been proposed to detect directed dynamical influences between time series. Two of the most used approaches are a model-free one (transfer entropy) and a model-based one (Granger causality). Several pitfalls are related to the presence or absence of assumptions in modeling the relevant features of the data. We tried to overcome those pitfalls using a neural network approach in which a model is built without any a priori assumptions. In this sense this method can be seen as a bridge between model-free and model-based approaches. The experiments perfo…

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…

Price dispersion, competition, and the role of online travel agents: Evidence from business routes in the Italian airline market

2014

Abstract In this article, using data from the Italian airline market, we study the role of online travel agents (OTAs) in driving price dispersion as compared to the effect of airlines’ websites. Specifically, we investigate how distinctive factors between OTAs and airlines’ direct channels influence price dispersion. We find that after controlling for OTAs’ features related to airline competition, price dispersion should be lower in the OTA channel relative to airlines’ direct channels. On the other hand, we also find that OTAs’ features related to the presence of airline competition play in favor of higher price dispersion in such indirect channel.

Biopharmaceutical alliances and competition: a real options game approach

2013

Start-up with or without inoculum? Analysis of an SMBR pilot plant.

2010

This study analysed a submerged membrane bioreactor (SMBR) start-up with the purpose of determining the best conditions to carry it out. In order to do this, a hollow fibre membrane module was installed in a submerged configuration in a pilot aerobic reactor. The experiment was then divided in two phases, lasting 65 days each. During phase 1, the pilot plant was started-up without inoculum of activated sludge and no sludge, withdrawal was performed. Conversely, in phase 2, the MBR pilot plant was started-up with sludge inoculum and the sludge concentration was kept constant. In both phases, the volumetric loading rate applied to the pilot plant was kept constant. The authors analysed the di…

Numerical and Experimental Analysis of the Frictional Effects on 4ENF Delamination Tests Performed on Unidirectional CFRP

2015

Abstract Progressive delamination in composite materials under static or fatigue loading condition are, in many structures, one of the predominant cause of failure. In the paper, an accurate study of quasi-static delamination growth under mode II loading condition is conducted. Several experimental tests are performed on composite laminates consisting of unidirectional carbon/epoxy layers. Four-point end-notched flexure (4ENF) test is employed in order to characterize the mode II interlaminar fracture toughness. The R-curve is obtained by means of optical and numerical determination of crack tip position. The energy release rate and the crack length are calculated through experimental deter…

A Fiber Optic Strain Gage Sensor for Measuring Preload in Thick Composite Bolted Joints

2019

Mechanical fastening is a popular choice in joining composites because of the ability to transfer high loads and the ease of assembly and disassembly. In this study, the failure behavior of composite–aluminum single lap bolted joint is investigated. In particular, the effects of varying the preload on the bolt are examined. In order to accurately measure the preload, a specialized sensor that uses a fiber Bragg grating sensor embedded in the bolt is proposed and created. This sensor is realized for the current tests but can be expanded to other applications. An experimental study of bolted single-lap joints varying the tightening torque value has been carried out and, in order to validate t…

Regional variation of wall shear stress in ascending thoracic aortic aneurysms.

2014

The development of an ascending thoracic aortic aneurysm is likely caused by excessive hemodynamic loads exerted on the aneurysmal wall. Computational fluid-dynamic analyses were performed on patient-specific ascending thoracic aortic aneurysms obtained from patients with either bicuspid aortic valve or tricuspid aortic valve to evaluate hemodynamic and wall shear parameters, imparting aneurysm enlargement. Results showed an accelerated flow along the outer aortic wall with helical flow in the aneurysm center for bicuspid aortic valve ascending thoracic aortic aneurysms. In a different way, tricuspid aortic valve ascending thoracic aortic aneurysms exhibited normal systolic flow without su…

Numerical methods in the design process of a sailing yacht

2014

Information decomposition of short-term cardiovascular and cardiorespiratory variability

2013

We present an entropy decomposition strategy aimed at quantifying how the predictive information (PI) about heart rate (HR) variability is dynamically stored in HR and is transferred to HR from arterial pressure (AP) and respiration (RS) variability according to synergistic or redundant cooperation. The PI is expressed as the sum of the self entropy (SE) of HR plus the transfer entropy (TE) from RS,AP to HR, quantifying respectively the information stored in the cardiac system and transferred to the cardiac system to the vascular and respiratory systems. The information transfer is further decomposed as the sum of the (unconditioned) TE from RS to HR plus the TE from SP to HR conditioned to…