Modelling Inductive Sensors for Arc Fault Detection in Aviation.

Modern aircraft are being equipped with high-voltage and direct current (HVDC) architectures to address the increase in electrical power. Unfortunately, the rise of voltage in low pressure environments brings about a problem with unexpected ionisation phenomena such as arcing. Series arcs in HVDC cannot be detected with conventional means, and finding methods to avoid the potentially catastrophic hazards of these events becomes critical to assure further development of more electric and all electric aviation.

Perinatal outcomes in children born after fresh or frozen embryo transfer using donated oocytes.

Study Question: Do children born after vitrified-thawed embryo transfers (ETs) using donated oocytes have worse perinatal outcomes when compared with fresh ET?

Summary Answer: No significant difference in birthweight and prematurity rates between fresh or frozen embryo transfers (FETs) in newborns after oocyte donation was found.

What Is Known Already: Autologous singletons born after fresh ET have been previously associated with higher rates of preterm birth and low birthweight, while FETs seem to confer a higher risk of hypertensive disorders during pregnancy and macrosomia. However, studies comparing these outcomes using autologous oocytes are unable to adequately disentangle the putative detrimental consequences of embryo vitrification from the possible effects that ovarian stimulation and endometrial preparation may have on endometrial receptivity prior to ET.

Radio-Frequency Localization of Multiple Partial Discharges Sources with Two Receivers.

Spatial localization of emitting sources is especially interesting in different fields of application. The focus of an earthquake, the determination of cracks in solid structures, or the position of bones inside a body are some examples of the use of multilateration techniques applied to acoustic and vibratory signals. Radar, GPS and wireless sensors networks location are based on radiofrequency emissions and the techniques are the same as in the case of acoustic emissions.

Partial Discharge Spectral Characterization in HF, VHF and UHF Bands Using Particle Swarm Optimization.

The measurement of partial discharge (PD) signals in the radio frequency (RF) range has gained popularity among utilities and specialized monitoring companies in recent years. Unfortunately, in most of the occasions the data are hidden by noise and coupled interferences that hinder their interpretation and renders them useless especially in acquisition systems in the ultra high frequency (UHF) band where the signals of interest are weak. This paper is focused on a method that uses a selective spectral signal characterization to feature each signal, type of partial discharge or interferences/noise, with the power contained in the most representative frequency bands.

Survey on the Performance of Source Localization Algorithms.

The localization of emitters using an array of sensors or antennas is a prevalent issue approached in several applications. There exist different techniques for source localization, which can be classified into multilateration, received signal strength (RSS) and proximity methods. The performance of multilateration techniques relies on measured time variables: the time of flight (ToF) of the emission from the emitter to the sensor, the time differences of arrival (TDoA) of the emission between sensors and the pseudo-time of flight (pToF) of the emission to the sensors.

Detection of Partial Discharge Sources Using UHF Sensors and Blind Signal Separation.

The measurement of the emitted electromagnetic energy in the UHF region of the spectrum allows the detection of partial discharges and, thus, the on-line monitoring of the condition of the insulation of electrical equipment. Unfortunately, determining the affected asset is difficult when there are several simultaneous insulation defects. This paper proposes the use of an independent component analysis (ICA) algorithm to separate the signals coming from different partial discharge (PD) sources.

Ultrasonic bone localization algorithm based on time-series cumulative kurtosis.

The design and optimization of protective equipment and devices such as exoskeletons and prosthetics have the potential to be enhanced by the ability of accurately measure the positions of the bones during movement. Existing technologies allow a quite precise measurement of motion-mainly by using coordinate video-cameras and skin-mounted markers-but fail in directly measuring the bone position. Alternative approaches, as fluoroscopy, are too invasive and not usable during extended lapses of time, either for cost or radiation exposure.

Antenna Deployment for the Localization of Partial Discharges in Open-Air Substations.

Partial discharges are ionization processes inside or on the surface of dielectrics that can unveil insulation problems in electrical equipment. The charge accumulated is released under certain environmental and voltage conditions attacking the insulation both physically and chemically. The final consequence of a continuous occurrence of these events is the breakdown of the dielectric.

Biodiesel from waste cooking oil in Mexico City.

The aim of this article is to evaluate the potential use of biodiesel produced from waste cooking oil in Mexico City. The study is divided in two main areas: the analysis of a waste cooking oil collection pilot project conducted in food markets of a Mexico City region; and the exhaust emissions performance of biodiesel blends measured in buses of the Mexico City public bus transportation network (RTP). Results from the waste cooking oil collection pilot project show that oil quantities disposed depend upon the type of food served and the operational practices in a cuisine establishment.

Separation of radio-frequency sources and localization of partial discharges in noisy environments.

The detection of partial discharges (PD) can help in early-warning detection systems to protect critical assets in power systems. The radio-frequency emission of these events can be measured with antennas even when the equipment is in service which reduces dramatically the maintenance costs and favours the implementation of condition-based monitoring systems. The drawback of these type of measurements is the difficulty of having a reference signal to study the events in a classical phase-resolved partial discharge pattern (PRPD).

Development of a moisture-in-solid-insulation sensor for power transformers.

Moisture is an important variable that must be kept under control to guarantee a safe operation of power transformers. Because of the hydrophilic character of cellulose, water mainly remains in the solid insulation, while just a few parts per million are dissolved in oil. The distribution of moisture between paper and oil is not static, but varies depending on the insulation temperature, and thus, water migration processes take place continuously during transformers operation.

Inductive sensor performance in partial discharges and noise separation by means of spectral power ratios.

Partial discharge (PD) detection is a standardized technique to qualify electrical insulation in machines and power cables. Several techniques that analyze the waveform of the pulses have been proposed to discriminate noise from PD activity. Among them, spectral power ratio representation shows great flexibility in the separation of the sources of PD.

Self-integrating inductive loop for measuring high frequency pulses.

High frequency pulses can be measured by means of inductive sensors. The main advantage of these sensors consists of non-contact measurements that isolate and protect measuring equipment. The objective of this paper is to present the implementation of an inductive sensor for measuring rapidly varying currents.

Inductively coupled probe for the measurement of partial discharges.

Partial discharges are a transient phenomena whose measurement is remarkably important for electrical equipment diagnosis and maintenance. These discharges appear in the measurement circuit as very narrow current pulses of some nanoseconds. Therefore, discharge pulse detection is a particularly difficult problem, especially because they are superposed on the high voltage waveforms that cause them.

Endocrine gland-derived vascular endothelial growth factor in rat pancreas: genetic expression and testosterone regulation.

Endocrine gland-derived vascular endothelial growth factor (EG-VEGF) is an endothelial cell mitogen, expressed essentially in steroidogenic cells. Recently, the expression of EG-VEGF in normal human pancreas and pancreatic adenocarcinoma has been demonstrated. Epidemiologically, pancreatic carcinogenesis is more frequent in males than females, and given that androgen receptors and testosterone biotransformation have been described in pancreas, we hypothesized that testosterone could participate in the regulation of EG-VEGF expression.

[Pancreatoduodenectomy: results in a large volume center].

Objective: Analyze the experience with pancreaticoduodenectomy (PD) at the INCMNSZ.

Background Data: PD has become a popular procedure in hospitals throughout the USA and Europe in the last 25 years, where mortality is < 5% y morbidity remains around 40%. Nonetheless there are very few reports on PD in Latin America.