Monitoring high‐temperature sensor with optical performance using graphene in power plant industries

Nano optical temperature sensor based on fiber Bragg grating using graphene

A high sensitive fiber Bragg grating (FBG) acceleration sensor based on filtering demodulation is analyzed on sensitivity, resolution and temperature experiment. Sensitivity and resolution of FBG sensor lies on the structure of the sensor shell and the shape of the reflec tivity spectrum of FBG. The temperature ex periments of the FBG sensor show the work and storing temperature range of the sensor based on different preparing stress and packaging glue. Experiments on the detecting system’s frequency character have been done. Results show that this acceleration sensor can detect the smallest acceleration of 1mm/s 2 with a flat response from 5Hz to 40Hz. Keywords: FBG, sensitivity, high temperature, low temperat ure, acceleration, sensor, modulation, experiment 1. INTRODUCTION In recent years, significant progresses have been gotten in the field of fiber- optic acceleration sensors. There has been considerable interest devoted in fiber-optic acceleration sensors because they afford all the advantages inherent with fiber optic sensors. Various types of fiber-op tic acceleration sensors have been widely used in fields of oil well logging, inertial navigation systems, earthquake monitoring, micro-seis mic monitoring and forecast of rock layer movement. So far, the fiber-optic acceleratio n sensors with high sensitivity, wide dynami c range, high resolution and compact size are urgently required. As a research aspect towards this direction, many kinds of fiber-optic acceleration sensors have been proposed

Real-time gas sensors, which use chemiresistive metal oxide (MO) semiconductors, have become more important in both research and industry. Fiber optic metal oxide (MO) semiconductor sensors have so increased the utility and demand for optical sensors in a variety of military, industrial, and social applications. Fiber optic sensors’ inherent benefits of lightweight, compact size, and low attenuation were actively leveraged to overcome their primary disadvantage of expensive cost. With the growing need for quicker, more precise, and simpler gas sensing, metal oxide semiconductor gas sensors are focusing on new and novel materials at room temperature. The realization that materials with coexisting magnetic and ferroelectric orders offer up effective ways to alter magnetism using electric fields has drawn scientists from diverse areas together to research multiferroics for gas sensing applications in recent years. The chapter shall encompass a brief summary of the underlying physics related to fiber optic gas sensors and parameters involved in gas sensing, the significance of the fascinating class of metal oxide materials, and an outline of spin frustrated multiferroics for possible applications and its potential possibilities for progress in the future.

Embedded optical fibre sensors (OFSs) offer the potential to monitor the internal strains at various stages during the manufacturing and service life of fibre-reinforced polymer (FRP) composite structures. Various aspects associated with the embedment of OFSs, such as integration, material compatibility, and sensing performance of the embedded sensor needs to be investigated to develop reliable OFSs based internal sensing platform for composite structures. In this study, Polyimide (PI) and Polyether ether ketone (PEEK) coated optical fibres (OF) were embedded into glass fibre-reinforced polymer (GFRP) composites to evaluate four important aspects associated with the embedment of OFs, which include; i). Structural integrity of the OFs against chemical reactions from vinyl ester resin and its additives through immersion testing, ii). Methods of integrating the OFs into layered glass fibres for the vacuum resin infusion manufacturing process, iii). Sensing performance of the embedded OFs during manufacturing and structural testing (tensile and compressive), and iv). Internal structural integrity of the embedded OFs and the host composite structure using X-Ray micro-computerised tomography technique (μ-CT). The results from the immersion testing and manufacturing process monitoring showed that both PEEK and PI coated OFs can resist the chemical and mechanical stresses caused by resin polymerisation during curing process. The subsequent mechanical testing showed a similar sensing performance by the PI and PEEK coated OFs. Under tensile loads, the OFs monitored the tensile strain distribution up to 7,000 με and compressive strain distribution up to −1,200 με under flexural loading without compromising their optical performance. Finally, the μ-CT scanning results had shown a minimal structural deterioration of the embedded OFs and host composite structure. The outcomes from this detailed experimental investigation on the embedment of OFS in GFRP structures provided useful information towards the integration and performance of optical sensors in composite structures.

The purpose of this study was to determine cholesterol concentration by developing the performance of optical sensors. The use of this optical sensor is equipped with an optical fiber bundle to guide the wave in the hope of not reducing the intensity of the wave source. This sensor is simpler and inexpensive to use to determine the concentration of a material. The research method for determining cholesterol levels can be determined through the character of the laser beam to the material through a fiber optic sensor. The optical fiber sensor method is simpler and cheaper to use to determine the concentration of a material. Based on this description, research on fiber optic sensors will be developed as an instrument model to determine cholesterol concentration using a fiber optic bundle type sensor. The method used is the modulation of laser beam intensity. A beam of light that enters the optical fiber of the receiver and is processed by an optical detector into an electrical signal that will be displayed on the computer. The experimental results will obtain a linear relationship between the sensor output peak voltage as a function of variations in cholesterol concentration and parameters and sensor performance will be measured including sensitivity and linearity. The results showed that maximum voltage detection showed a linear decrease with increasing concentration with a sensitivity of 0.15 mV/ppm and a linearity of more than 97%. high sensitivity, simplicity of design, and low cost of promoting the developed sensor results in good performance detecting cholesterol concentration.

Optical fibre sensors (OFS) are worthy of interest for measurements in nuclear reactor thanks to their unique features, particularly compact size and remote multi-point sensing for some of them. But besides non negligible constraints associated with the high temperature environment of the experiments of interest, it is well known that the performances of OFS can be severely affected by high level of radiations. The Radiation Induced Attenuation (RIA) in the fibre is probably most known effect, which can be to some extent circumvented by using rad hard fibres to limit the dynamic loss. However, when the fast neutron fluence reaches 1018 to 1019 n/cm2, the density and index variations associated to structural changes may deteriorate drastically the performances of OFS even if they are based on rad hard fibres, by causing direct errors in the measurements of temperature and/or strain changes. The aim of the present study is to access the effect of nuclear radiations on the Fabry Perot (FP) and of Fibre Bragg Grating (FBG) sensors through the comparison of measurements made on these OFS - or part of them - before and after irradiation [1]. In the context of development of OFS for high irradiation environment and especially for Material Testing Reactors (MTRs), Sake 2 experiment consists in an irradiation campaign at high level of gamma and neutron fluxes conducted on samples of fibre optics – bare or functionalised with FBG. The irradiation was performed at two levels of fast neutron fluence: 1 and 3.1019 n/cm2 (E>1MeV), at 250°± 25°C, in the SCK•CEN BR2 reactor (Mol Belgium). An irradiation capsule was designed to allow irradiation at the specified temperature without active control. The neutron fluence was measured with activation dosimeters and the results were compared with MCPN computations. Investigation of bare samples gives information on the density changes, while for the FBGs both density and refractive index perturbation are involved. Some results for bare fibres were reported recently. In this paper, we will focus on the measurements made on FBGs that have been manufactured by different laboratories on SMF 28 fibers: CEA, University of St-Etienne and University of Mons. Tested gratings have been written using various conditions (type of fibre, of laser, writing wavelength, power density, post writing thermal annealing,…), leading to various behaviours after Sake 2 irradiation. Bragg wavelength and reflectivity have been measured before and after irradiation thanks to a special mounting at the same temperature. It appears that a change in the shape after irradiation of the Bragg peak disturb the retrieval of the Bragg wavelength. The measurements show that for nearly all gratings the Bragg peak remains visible after the irradiation, and that Radiation Induced Bragg Wavelength Shifts (RI-BWSs) vary from few pm (equivalent to an error of less than 1°C for a temperature sensor) to nearly 1 nm (equivalent to 100°C) depending of the FBG types. High RI-BWSs could indeed be expected when considering the huge refractive index variation and compaction of the bare fibre samples that have been measured by other techniques. Post writing thermal annealing is confirmed as a key parameter in order to obtain a more radiation tolerant FBG. Our results show that specific annealing regimes allow making FGBs suitable to perform temperature measurements in a MTR experiment.

Recent research progress of optical fiber sensors based on D-shaped structure

High sensitivity fiber optic pressure sensor is in great demand in in all aspects due to its advantages. However, the current high sensitivity optical fiber pressure sensor has the problems of large size and high cost. An optical fiber pressure sensor based on all-silica Fabry-Perot interference has been proposed in this paper. The sensor consists of single mode fiber, silica capillary and diaphragm made of coreless optical fiber. The diameter of the sensor is only 125 μm. With precise control of diaphragm thinning, the diaphragm thickness of F-P sensor is only 1.477 μm, the sensor manufactured in this way has sensitivity with 12.586 rad/MPa. The sensor is ease of manufacturing and low cost. Static calibration shown the advantages of the sensor are high sensitivity, good linearity, repeatability, reliability and low hysteresis.

Fiber optic displacement sensors are widely used in industry due to advantages such as simple design, low cost and immune to RFI and EMI. Non-contact type fiber optic sensors are popularly known as retroreflective type of extrinsic sensors. Due to its inherent advantages, retro reflective extrinsic Fiber optic sensors (FOS) have been examined, statistically modelled, and tested for performance. This paper reports easy pathway to study, analyze and optimize the retroreflective extrinsic type FOS as a software tool ‘FOS Explore’. This tool was created utilizing the ray tracing technique and a generalized mathematical model of FOS. Sensor geometries can be set and performance characteristics can be examined. The software, which was created using MATLAB, allows users to input various fiber specifications and geometrical factors in order to determine the sensor's layout. For ease of comprehension, the simulated results are presented in the form of a tabular display, particular plots, and cross sectional views of sensor geometry. This software program is used to examine and optimize multiple architectures based on performance factors such as sensitivity and linear operating range at certain non linearity, in addition to basic configuration.

In order to increase throughput and maximize sensitivity the next-generation of astronomical instrumentation is moving toward cryogenic, all-reflective, off-axis optical design solutions. These off-axis systems require mirrors which are produced with complex conic sections, demand a thermal optical performance at cryogenic temperatures, and must support lifetimes on the order of 5-10 years. SSG specializes in the design, development, fabrication and testing of off-axis, all-reflective optical systems, having produced > 40 such systems over the last 20 years. The majority of these system have been produced using nickel plated aluminum mirror substrates and aluminum metering structures in order to obtain a passively systems has long been a point of debate. In this paper we demonstrate the long term stability of nickel plated aluminum optics by presenting interferometric test data obtained on > 10 optical elements over a period of 10 years. Cryogenic stability is demonstrated by presenting system level wavefront data obtained over a wide thermal range down to 115K. In addition, we will present thermal test data obtained from a number of alternate metal optical materials: beryllium, bare aluminum, and aluminum/beryllium alloys.

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper OTC 27987, “Subsea-Fiber Wet-Mate Connectors: Achieving the Balance Between Consistent Optical Performance, Product Cost, and Compact Size,” by Elaine Saxton and Helyson Parente, SPE, Siemens Subsea, prepared for the 2017 Offshore Technology Conference Brasil, Rio de Janeiro, 24–26 October. The paper has not been peer reviewed. Copyright 2017 Offshore Technology Conference. Reproduced by permission. As the hunger for data grows, long stepouts become more common, and fiber communication becomes standard, the use of fiber in subsea oil and gas fields is set to increase. While optical loss along fiber itself is low and data-collection possibilities are high, these applications will only be fully realized if wet-mate fiber connectors can achieve high optical performance consistently. Excellent results are achieved with compact design, a modular approach, and an emphasis on cleanliness. Introduction Wet-mate fiber connectors have been on the market for years and are used increasingly in the subsea oil and gas industry. While they have been moderately successful, the technical challenges should not be underestimated. Industry specifications demand high levels of optical performance and extensive qualification programs. The balance between performance and cost of the finished product has always been difficult to achieve. Subsea fields are seeing longer stepouts, which are suited to using fiber as the key communication network. Furthermore, the subsea industry is seeing an ongoing drive to use fiber sensors in downhole systems (e.g., distributed temperature sensing), allowing greater amounts of data to be transmitted topside. Other applications such as direct-current and fiber-optic distribution and pipe-in-pipe heating are also emerging. For reasons of flexibility and practicality, the wet-mate fiber connector plays an important role in all of these. Technical Challenges The key technical challenges are a mixture of mechanical design, operation and maintenance, and operational environment. Mechanical Design. The core of a standard single-mode fiber is 9 µm, and it must be completely aligned in every dimension for optical performance to be achieved. Manufacturing, Operation, and Maintenance. Cleanliness of the optical ferrule faces on every single mate is crucial. Without it, performance is degraded or lost. In the worst case, permanent damage is transferred by a dirty ferrule face mating with a clean one. Operational Environment. A wet-mate connector is a sealed, oil-filled, pressure-balanced mechanical device that will be handled in harsh topside conditions in extreme temperatures before being deployed to sea depths of up to 4,000 m. Operation and Maintenance. High optical performance is required on all lines for up to 1,000 mates. Subsea connectors typically are mated only a few times in deployment and lifetime operation, but the same connectors are used for testing topside where they see many more mates. Compact Size. Space on subsea equipment structures is always at a premium, and designs always need to be as efficient with space as possible.

The detection of Cadmium (Cd) in palm oil using optical fiber sensors had been simulated utilizing the Finite Element Method (FEM) approach to investigate sensor performance. The optical fiber sensor was developed using chitosan reagents for better detection performance. The optical fiber was built using a silica core with a refractive index of 1.45, and cladding was replaced by the result reaction between chitosan and oil with a refractive index of 1.333. The study aims to observe the effect of reagent thickness that varied 0.1 to 0.5 mm for sensor performance to detect Cd in oil with a concentration variation of 0.05 - 0.5 ppm using a 650 nm red beam source. The results show that increasing the reagent’s thickness can reduce the beam’s confinement factor in optical fiber from 90.224 to 61.975. The reduction can be due to the mismatching of the refractive index between the core and cladding. The performance of the optical fiber sensor was examined using loss propagation and confinement factor in Cd concentration variation. For each reagent thickness, the results indicated that the loss propagation increased, and on the contrary, the confinement factor decreased as Cd concentration increased. The highest sensitivity of the sensor, calculated from the slope of the concentration vs. confinement factor graph, was obtained while using 0.5 cm reagent thickness with the value of 1.6267. It indicated that the reagent thickness could improve the optical fiber sensor performance, especially on Cd detection in oil.

In this paper, a high sensitive connector offset optical fiber sensor is employed to detect the refractive index of liquid. The configuration chosen for this experiment is formed by lateral core offset fusion splicing of no-core fiber (NCF) between the single mode fibers (SMF) and cladding modes are excited by misalignment. The sensing principle for refractive index detection is based on Mach-Zehnder Interferometer (MZI) principle and the experiment is carried out by immersion of device in NaCl solutions of different refractive indices. Such refractive index sensor exhibits high sensitivity 197.33 nm/RIU for the surrounding refractive index variation from 1.333 to 1.380, and the result shows the excellent agreement with theoretical analysis. Compared to other sensors, the proposed device has the potential to provide high sensitivity, ease of fabrication, low cost, compact size, and linear response. Thus, it can be used in many applications such as bio-sensors, chemical sensor, temperature sensor, and pressure sensor.

Efficient fossil energy use with low pollution in all kinds of power plants is of growing interest in all industrial sectors. The use of energy is growing steadily by many countries worldwide due to the greater desire for enhancing better standards of living and to increase productivity. Efficient energy use is favorable for better productivity product quality, costs, and quality of human life but the energy use adversely impacts our environment. During the past decade energy demands from China and India have grown significantly and is projected to grow even more in the coming decades as they enhance their living standards and productivity. This clearly requires close examination of the available methods of fossil fuel energy conversion as well as advanced methods that will provide increased efficiency and pollution reduction. This section, after brief review on historical perspectives on energy conversion, provides a short review on the various methods used for energy conversion in industrial power plants as well as new innovative methods that are now beginning to become available with significant fuel saving, compact size of the equipment and low pollution. As an example, high temperature air combustion technology has seen wider acceptance of the technology in many kinds of industrial furnaces, in particular, for use in steel industry and fuel reforming furnaces with demonstrated energy savings of about 30% (on the average), about 25% reduction in the size of the equipment (compact size), about 50% reduction in low pollution and better quality of the product produced. Such significant energy savings were only dream of engineers in the past. This technology has been adapted by many countries worldwide. In addition advanced technologies are developed or being developed for use with coals (and solid fuels) since its cost based on energy content is low as compared to gaseous fuels, such as natural gas. Several commonly used methods in power generation are presented along with integrated and hybrid systems for increased efficiency. Clear representation is provided of the output energy available from known input energy. Some energy conversion techniques provide in-situ capture of pollutants while others must use air pollution control devices for pollution capture and/or pollution reduction prior to waste gases discharge to the atmosphere. The information provides quick guide on the commonly used methods of energy conversion in the USA and Europe, in particular when using solid fuels, such as coal. It is expected that future systems will be more energy efficient and emit even lower pollution via the use of combined cycle systems and integrated energy conversion systems. Advanced high temperature steam gasification results in hydrogen-rich syngas of higher heating value, reduced volume of the waste, and the remaining residue is clean and non-leachable.

A novel digital phase detection method for frequency-modulated continuous-wave interferometric fiber-optic displacement sensor