Search results for "Oller"
showing 10 items of 265 documents
The chaotic Dadras–Momeni system: control and hyperchaotification
2015
In this paper a novel three-dimensional autonomous chaotic system, the so called Dadras-Momeni system, is considered and two different control techniques are employed to realize chaos control and chaos synchronization. Firstly, the optimal control of the chaotic system is discussed and an open loop feedback controller is proposed to stabilize the system states to one of the system equilibria, minimizing the cost function by virtue of the Pontryagin’s minimum principle. Then, an adaptive control law and an update rule for uncertain parameters, based on Lyapunov stability theory, are designed both to drive the system trajectories to an equilibrium or to realize a complete synchronization of t…
New ultraportable data logger to perform magnetic surveys
2019
This article presents the realization of a device for magnetic surveys It is a flexible, user-reprogramable, lightweight, and compact tool that can be easily integrated with aerial and marine drones. The device can accurately measure the local magnetic anomalies. It is based on the Atmega 2560 microcontroller and a digital 3-axis fluxgate magnetometer.
Health behaviours and mental and physical health status in older adults with a history of homelessness:a cross-sectional population-based study in En…
2019
Objectives: This study compared (1) levels of engagement in lifestyle risk behaviours and (2) mental and physical health status in individuals who have previously been homeless to those of individuals who have not. Design: Cross-sectional. Participants: Data were from participants (n=6931) of the English Longitudinal Study of Ageing. Measures: Participants reported whether they had ever been homeless. We used regression models to analyse associations between homelessness and (1) cigarette smoking, daily alcohol consumption and physical inactivity, adjusting for sociodemographic covariates (age, sex, ethnicity, highest level of education, marital status and household non-pension wealth) and …
The Grinding Resistance of the Wheat Grain Related to the Grinding Degree For The First Break In The Wheat Milling
2011
Breakage of wheat grain during first break roller milling depends on the characteristics of the wheat (including the distributions of kernel size, hardness and moisture content) and on the design and operation of the roller mill (including roll speeds and differential, roll disposition, fluting profile, number of flutes, fluting spiral, roll gap, the degree of roll wear and the feed rate). The effects of these factors are manifest in the particle size distribution exiting first break, the compositional distribution of those particles (as large particles tend to be richer in bran, while small particles are pure endosperm), the power required to mill the wheat and the rate of roll wear. For t…
Design and realization of a portable multichannel continuous wave fNIRS
2014
A design and implementation of a portable functional Near InfraRed Spectroscopy embedded system prototype is described. In this theoretical and experimental work, we present an embedded system hosting 64 LED sources and 128 Silicon PhotoMultiplier detectors (SiPM). The elementary part of the structure is a flexible probe “leaf” consisting of 16 SiPMs, 4 couples of LEDs, each operating at two wavelengths, and a temperature sensor. The hardware system is based on an ARM main microcontroller that allows to perform both the switching time of LEDs and the acquisition of the SiPM outputs. The performed preliminary experimental tests achieved very promising results, thus demonstrating the effectiv…
A procedure to achieve fine control in MW processing of foods
2007
Abstract A two-dimensional analytical model for predicting the unsteady temperature field in a cylindrical shaped body affected by spatially varying heat generation is presented. The dimensionless problem is solved analytically by using both partial solutions and the variation of parameters techniques. Having in mind industrial microwave heating for food pasteurization, the easy-to-handle solution is used to confirm the intrinsic lack of spatial uniformity of such a treatment in comparison to the traditional one. From an experimental point of view, a batch pasteurization treatment was realized to compare the effect of two different control techniques both based on IR thermography readout: t…
PPG embedded system for blood pressure monitoring
2014
In this work, we have designed and implemented a microcontroller-based embedded system for blood pressure monitoring through a PhotoPlethysmoGraphic (PPG) technique. In our system, it is possible to perform PPG measurements via reflectance mode. Hardware novelty of our system consists in the adoption of Silicon PhotoMultiplier detectors. The signal received from the photodetector is used to calculate the instantaneous heart rate and therefore the heart rate variability. The obtained results show that, by using our system, it is possible to easily extract both the PPG and the breath signal. These signals can be used to monitor the patients during the convalescence both in hospital and at hom…
A Computer Control System for the Hydraulic Stand MZPK 100 for Biaxial Fatigue Testing
2006
This paper presents a two-channel digital control system for the hydraulic stand MZPK 100 designed for fatigue tests of cruciform specimens under biaxial tension-compression. In the past, the fatigue test stand MZPK 100 was provided with unreliable analog control power cubicles. Application of the computer with an analog and digital input-output signal path board, Matlab/Simulink software and a new control box equipped with the necessary electronic subassemblies (responsible for proper switching of the hydraulic supplier, command electrovalves, conditioning of signals from sensors and so on) enables replacement of the old analog system by a new two-channel digital control system. Nowadays, …
A new gas sensor electronic interface with generalized impedance converter
2008
A new gas sensor conditioning circuit that allows a direct resistance-to-frequency conversion, as well as the procedure for the design, is presented. The generalized impedance converter (GIC) proposed is configured as a variable capacitor connected with the capacitor timing terminal of an astable multivibrator implemented by a PSoC (programmable system on chip) microcontroller device. The GIC effective input impedance, which is controlled by the gas sensor resistance, controls the astable output frequency. Good correlation of the experimental output frequency, which depends on the gas concentration, is achieved. The circuit is a simple gas sensor digital interface with frequency output.
Ultrasonic phased array inspection of wire plus arc additive manufacture samples using conventional and total focusing method imaging approaches
2019
In this study, three aluminium samples produced by wire + arc additive manufacture (WAAM) are inspected using ultrasonic phased array technology. Artificial defects are machined using a centre drill, ø 3 mm, and electrical discharge machining (EDM), ø 0.5-1 mm, in a cylindrical through-hole topology. The samples are first inspected using a single-element wheel probe mounted on a KUKA robot in order to investigate the feasibility of using a conventional ultrasonic transducer approach. Unfortunately, the wheel probe is found to be unsuitable for scanning the WAAM specimens and ultrasonic phased arrays are employed next. The set-up includes 5 MHz and 10 MHz arrays (128 elements) in direct cont…