In this paper, how structure-sensitive parameters derived from the hysteresis loop, like coercive... more In this paper, how structure-sensitive parameters derived from the hysteresis loop, like coercive field, remanent induction, and hysteresis losses, can be used to characterise recovery and recrystallization in cold rolled Ti-Nb stabilised interstitial free ultra low carbon steel is shown. The effect on hysteresis measurements of isothermal annealing treatments applied to industrially cold rolled samples at different temperatures is related
Electrical Systems for Aircraft, Railway and Ship Propulsion, 2010
This project has been oriented to the development of an energy system unit for powering tramways ... more This project has been oriented to the development of an energy system unit for powering tramways during shorts periods of time. The aim of this work is to present the results obtained for a high frequency DC-DC converter which is included in the energy unit. The energy unit will consist on two type of energy storage devices: a battery stack
A cold rolled low carbon steel has been annealed at sufficiently low temperatures (300 to 500 °C)... more A cold rolled low carbon steel has been annealed at sufficiently low temperatures (300 to 500 °C) in order to promote recovery without interaction with recrystallization. The recovery kinetics has been followed by using magnetic coercive field (Hc) measurements. The microstructural changes associated with the observed decrease in Hc, produced by the recovery, have been analysed by TEM observations. The experimental data have been adequately modelled using various formulations reported in the literature. The kinetics of the dislocation hardening contribution to the yield stress has been derived from the kinetics of the coercive field, taking into account the existing linear relationship between both variables.
ABSTRACT Bacterial biofilms are a common cause of persistent and chronic infections, mostly relat... more ABSTRACT Bacterial biofilms are a common cause of persistent and chronic infections, mostly related to implantable devices. In this context, Staphylococcus species are the most relevant microorganisms involved in causing high costs for the healthcare system. New diagnostic and/or therapeutic tools should be developed by providing in vivo analysis of the specific physiological parameters directly related to the status of the indwelling device. Monitoring the biofilm's biological evolution will allow an earlier diagnostic. Impedance microbiology is suggested as a proper technique for directly measuring the development of bacterial biofilms generated inside intravascular catheters. In this study we propose interdigitated microelectrode biosensors be integrated within those implantable devices. In vitro assays have been carried out in order to characterize this methodology as a detection and monitoring tool for bacterial biofilm development. Impedance spectroscopy (IS) was implemented in 96-well microtiter plates, leading to positive results in detecting and monitoring bacterial biofilm development. Two Staphylococcus aureus and two Staphylococcus epidermidis strains were successfully monitored during a 20-h culture, and results show that the low range of the frequency is the most suitable setting for measuring the maximum relative changes.
The recovery and recrystallization kinetics of a cold rolled interstitial free (IF) steel were st... more The recovery and recrystallization kinetics of a cold rolled interstitial free (IF) steel were studied during isothermal annealing. Magnetic methods based on coercive field measurements, hardness tests and metallography were applied so as to follow the kinetics experimentally. The coercive field measurement technique reveals a higher degree of resolution for monitoring recovery than conventional hardness determination and also allows the recrystallization progress to be monitored. The results obtained are compared to those previously determined for a non-stabilized extra low carbon (ELC) steel. The observed differences are discussed in terms of the presence of microalloying elements, Ti and Nb, which slow down recovery and delay recrystallization.
This paper describes the design, implementation and validation of a sensitive and integral techno... more This paper describes the design, implementation and validation of a sensitive and integral technology solution for endotoxin detection.
ABSTRACT This paper presents a comparative study on time-to-digital converters (TDC) for their us... more ABSTRACT This paper presents a comparative study on time-to-digital converters (TDC) for their use as part of an RFID tag sensor. TDCs can digitize any physical magnitude previously converted to time delay and exploit the benefits of time domain conversion: high resolution with reduced power consumption and low voltage operation. Three different TDC architectures are analyzed and a calibration strategy tailored for RFID sensing applications is proposed in order to account for process variations. Converters implemented using a 0.18@mm CMOS standard process have been analyzed at transistor level for human body temperature sensing applications. An accuracy of 0.011^oC is achieved in the range from 35^oC to 43^oC for the nonius TDC with a power consumption of only 4.1nW at 10 samples per second from a 1.8V voltage supply.
In this paper, how structure-sensitive parameters derived from the hysteresis loop, like coercive... more In this paper, how structure-sensitive parameters derived from the hysteresis loop, like coercive field, remanent induction, and hysteresis losses, can be used to characterise recovery and recrystallization in cold rolled Ti-Nb stabilised interstitial free ultra low carbon steel is shown. The effect on hysteresis measurements of isothermal annealing treatments applied to industrially cold rolled samples at different temperatures is related
Electrical Systems for Aircraft, Railway and Ship Propulsion, 2010
This project has been oriented to the development of an energy system unit for powering tramways ... more This project has been oriented to the development of an energy system unit for powering tramways during shorts periods of time. The aim of this work is to present the results obtained for a high frequency DC-DC converter which is included in the energy unit. The energy unit will consist on two type of energy storage devices: a battery stack
A cold rolled low carbon steel has been annealed at sufficiently low temperatures (300 to 500 °C)... more A cold rolled low carbon steel has been annealed at sufficiently low temperatures (300 to 500 °C) in order to promote recovery without interaction with recrystallization. The recovery kinetics has been followed by using magnetic coercive field (Hc) measurements. The microstructural changes associated with the observed decrease in Hc, produced by the recovery, have been analysed by TEM observations. The experimental data have been adequately modelled using various formulations reported in the literature. The kinetics of the dislocation hardening contribution to the yield stress has been derived from the kinetics of the coercive field, taking into account the existing linear relationship between both variables.
ABSTRACT Bacterial biofilms are a common cause of persistent and chronic infections, mostly relat... more ABSTRACT Bacterial biofilms are a common cause of persistent and chronic infections, mostly related to implantable devices. In this context, Staphylococcus species are the most relevant microorganisms involved in causing high costs for the healthcare system. New diagnostic and/or therapeutic tools should be developed by providing in vivo analysis of the specific physiological parameters directly related to the status of the indwelling device. Monitoring the biofilm's biological evolution will allow an earlier diagnostic. Impedance microbiology is suggested as a proper technique for directly measuring the development of bacterial biofilms generated inside intravascular catheters. In this study we propose interdigitated microelectrode biosensors be integrated within those implantable devices. In vitro assays have been carried out in order to characterize this methodology as a detection and monitoring tool for bacterial biofilm development. Impedance spectroscopy (IS) was implemented in 96-well microtiter plates, leading to positive results in detecting and monitoring bacterial biofilm development. Two Staphylococcus aureus and two Staphylococcus epidermidis strains were successfully monitored during a 20-h culture, and results show that the low range of the frequency is the most suitable setting for measuring the maximum relative changes.
The recovery and recrystallization kinetics of a cold rolled interstitial free (IF) steel were st... more The recovery and recrystallization kinetics of a cold rolled interstitial free (IF) steel were studied during isothermal annealing. Magnetic methods based on coercive field measurements, hardness tests and metallography were applied so as to follow the kinetics experimentally. The coercive field measurement technique reveals a higher degree of resolution for monitoring recovery than conventional hardness determination and also allows the recrystallization progress to be monitored. The results obtained are compared to those previously determined for a non-stabilized extra low carbon (ELC) steel. The observed differences are discussed in terms of the presence of microalloying elements, Ti and Nb, which slow down recovery and delay recrystallization.
This paper describes the design, implementation and validation of a sensitive and integral techno... more This paper describes the design, implementation and validation of a sensitive and integral technology solution for endotoxin detection.
ABSTRACT This paper presents a comparative study on time-to-digital converters (TDC) for their us... more ABSTRACT This paper presents a comparative study on time-to-digital converters (TDC) for their use as part of an RFID tag sensor. TDCs can digitize any physical magnitude previously converted to time delay and exploit the benefits of time domain conversion: high resolution with reduced power consumption and low voltage operation. Three different TDC architectures are analyzed and a calibration strategy tailored for RFID sensing applications is proposed in order to account for process variations. Converters implemented using a 0.18@mm CMOS standard process have been analyzed at transistor level for human body temperature sensing applications. An accuracy of 0.011^oC is achieved in the range from 35^oC to 43^oC for the nonius TDC with a power consumption of only 4.1nW at 10 samples per second from a 1.8V voltage supply.
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