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The use of optical fibers is increasing in modern aircraft because this helps solve challenges of size, weight, communication, and reliability in new generation aircraft. This study describes a video and power transmission system using optical fibers (PoF) for in-flight entertainment (IFE) system application. We present the benefits and the limitations of this application, and we perform two practical experiments to demonstrate their performance. We used off-the-shelf devices in the experiments, such as one 15-Watt semiconductor laser operating at 808 nm, GaAs photovoltaic converters, optical transmitters and receivers, and video monitors. The power and video signals were transmitted using two 50-m length multimode fibers. In addition, we proposed and tested two types of energy transformation units (ETUs), which are responsible for supplying electrical energy to the IFE video monitor and the optical fiber receiver. [ABSTRACT FROM AUTHOR]

This work presents a multi-parameter optical fiber monitoring solution applied to an underground power distribution network. The monitoring system demonstrated herein uses Fiber Bragg Grating (FBG) sensors to measure multiple parameters, such as the distributed temperature of the power cable, external temperature and current of the transformers, liquid level, and intrusion in the underground manholes. To monitor partial discharges of cable connections, we used sensors that detect radio frequency signals. The system was characterized in the laboratory and tested in underground distribution networks. We present here the technical details of the laboratory characterization, system installation, and the results of 6 months of network monitoring. The data obtained for temperature sensors in the field tests show a thermal behavior depending on the day/night cycle and the season. The temperature levels measured on the conductors indicated that in high-temperature periods, the maximum current specified for the conductor must be reduced, according to the applied Brazilian standards. The other sensors detected other important events in the distribution network. All the sensors demonstrated their functionality and robustness in the distribution network, and the monitored data will allow the electric power system to have a safe operation, with optimized capacity and operating within tolerated electrical and thermal limits. [ABSTRACT FROM AUTHOR]

This article presents a proposal for an alternative approach for simultaneous measurement of electric current and temperature using an optical sensor based on magnetostrictive material that employs a single Fiber Bragg Grating (FBG). The sensor head is of simple design and allows easy installation on the existing conductors of the underground distribution network. This proposal measures the root mean square (RMS) current from 50 to 600 A at any temperature between 10°C to 60°C, real values for a distribution network. The approach consists of obtaining surface curves of two key parameters of the sensor’s waveform response, $\lambda ({t})$. The main parameters are the peak-to-peak and minimum wavelengths as a function of temperature and current. When determining these parameters from the waveform, the crossing point of the contour graphics is used to uniquely determine the current and temperature in the sensor head in real-time, without the need for any correction process. [ABSTRACT FROM AUTHOR]

In this paper, we proposed a sealing method of fiber Bragg grating (FBG) in pressure sensors using electroless nickel-plating. The sensor is designed to be used in harsh environments of thermoelectric power plant engines. In order to be applied in the engine injector nozzle, the FBG has just a single attached point in the pressure sensor and the combustion chamber pressure will freely compress the FBG. The fixation material used to seal the FBG in the pressure sensor is the key for the sensor performance considering the engine environment used in thermoelectric power plant. Typical level of pressure in the engine monitoring point is around 200 bar and the temperature exceeds 300 °C. We detailed the method of fabrication and the characteristics of this method. Next, the FBG pressure sensors using electroless nickel-plating sealing were studied and submitted to laboratorial and field trial evaluation. In addition, we evaluated the signal characteristics of the FBG pressure sensor and we compared it with a standard pressure sensor used in this application. [ABSTRACT FROM AUTHOR]

Complex suicides are rare and consist in the use of more than one method to induce death, representing a challenging investigation for forensic pathologists. According to the several combinations reported in literature, they have been classified into "typical" (where two common suicide methods are associated) and "atypical" (where more than two methods, or infrequent combinations of suicide methods are involved). In the case discussed here, an elderly man suffering of depression was found dead inside the tool shed of his house with a knife embedded in the abdomen and two plastic bags fastened around the neck using a twine. Three other superficial stab wounds were clustered close to the penetrating lesion. Internal examination revealed haemorrhagic infiltration at the mesentery and haemoperitoneum. No evident signs of asphyxia were highlighted and the cause of death was attributed to haemorrhagic shock. This association of suicide methods has turned out to be unusual. A review of the literature concerning complex suicides, abdominal self-stabbing and plastic bag suffocation has been managed. Crime scene and details of the used tools, medical and psychiatric history of the victim and features of the internal and external lesions have been examined and compared to previous studies. Toxicological analyses were not performed. [ABSTRACT FROM AUTHOR]

Electron BackScatter Diffraction (EBSD) in conjunction with Field-Emission Environmental Scanning Electron Microscopy (FEG-ESEM) has been used to evaluate the microstructural and local plastic strain evolution in different alloys (AISI 1005, AISI 304L and Duplex 2205) deformed by a single-stage cold and warm forging process. The present work is aimed to describe the different behavior of the austenite and ferrite during plastic deformation as a function of different forging temperatures. Several topological EBSD maps have been measured on the deformed and undeformed states. Then, image quality factor, distributions of the grain size and misorientation have been analyzed in detail. In the austenitic stainless steel, the -phase has been found to harden more easily, then -phase and -phase in AISI 1005 and in duplex stainless steel, sequentially. Compared to the high fraction of continuous dynamic recrystallized austenitic zones observed in stainless steels samples forged at low temperatures, the austenitic microstructure of samples forged at higher temperatures, 600-700 °C, has been found to be mainly characterized by large and elongated grains with some colonies of fine nearly-equiaxed grains attributed to discontinuous dynamic recrystallization. [ABSTRACT FROM AUTHOR]

This paper described a distributed temperature sensing (DTS) system based on Raman scattering using pre-shaped simplex code (S code) with erbium-doped fiber amplifiers (EDFAs) transient effects suppression techniques. We investigated these techniques to mitigate the waveform distortion caused by the EDFA when DTS uses S code in an optical time-domain reflectometer (OTDR). We tested the DTS experimentally using two EDFA’s transient effects suppression techniques: automatic gain control and pre-shaped S code pulses. The performance of these two techniques working simultaneously was compared with the standard S code technique. In the experimental setup, we tested code word lengths from 3 to 127 b with 100-ns pulsewidth. The temperature measurement demonstration was done in reaches of 40 and 50 km, and in a repeated system of 62 km using standard single-mode fiber and commercial OTDR and EDFA modules, which were properly adapted to this application. Results show that EDFA’s transient effects suppression techniques allow increasing the reach of DTS using short S code sequences, reducing the complexity and the processing time. [ABSTRACT FROM PUBLISHER]

This paper presents the results of a quantitative and qualitative monitoring system for switchgear with full electrical isolation using fiber-optic technology that aims to help in the automation of substations. The remote sensors were installed near each phase of the switchgear and they are powered only by the optical power provided by one pair of optic fibers connected to a remote optical source. At the same time, part of the optical supply power is used to measure the contact quality by using the optical triangulation method. Two microcameras installed in each remote sensor allow for the observation of the switchgear contact and hinge. All data are transmitted by the optical fibers to a control unit installed in the substation room, and from that, the data are transmitted to the utilities' operating center using the utilities commercial telecom optical network. We describe the system design, laboratory tests, and the field trial conducted in a 138-kV distribution substation. [ABSTRACT FROM AUTHOR]

In this work, we present the design, laboratory tests, and the field trial results of a power-over-fiber (PoF) low power instrument transformer (LPIT) for voltage and current measurements in the medium voltage distribution networks. The new proposed design of this power-over-fiber LPIT aims to overcome the drawbacks presented by the previous technologies, such as the continuous operation (measuring and data transmission) for a wide current range conducted in the medium voltage transmission lines, damage due to lightning strikes, accuracy dependency on vibration, position and temperatures. The LPIT attends the accuracy criteria of IEC 61869-10 and IEC 61869-11 in terms of current and voltage accuracy and it attends the practical criteria adopted by Utilities companies including voltage measurements without removing the coating of the covered conductors. The PoF based LPIT was developed to be applied at 11.9 kV, 13.8 kV, and 23.0 kV phase-to-phase nominal voltages, and in two current ranges 1.25–30 A and 37.5–900 A. The digital data transmission of current, voltage, and temperature from the sensing unit to the processing unit uses a special synchronism technique and it is performed by two 62.5 µm multimode fibers in 850 nm. The optical powering in 976 nm is also performed by one 62.5 µm multimode fiber from the processing unit to the sensor unit. We presented all details of the sensor design and its laboratory characterization in terms of accuracy and temperature correction. We also presented the results of field tests of the sensor made in two different conditions: in a standard distribution network and an experimental hybrid fiber/power distribution network. We believe that these studies aim to incorporate optical fiber and devices, digital technologies, communications systems in electrical systems driving their evolution. [ABSTRACT FROM AUTHOR]