scholarly journals Applications of Fiber Bragg Grating Sensors in the Composite Industry

MRS Bulletin ◽  
2002 ◽  
Vol 27 (5) ◽  
pp. 400-407 ◽  
Author(s):  
Pierre Ferdinand ◽  
Sylvain Magne ◽  
Véronique Dewynter-Marty ◽  
Stéphane Rougeault ◽  
Laurent Maurin
Keyword(s):  
Electromagnetic Interference ◽  
Composite Structures ◽  
Civil Engineering ◽  
Cost Effective ◽  
Industrial Applications ◽  
Fiber Sensors ◽  
Impact Detection ◽  
Remote Measurements ◽  
Temperature Strain

AbstractOptical-fiber sensors based on fiber Bragg gratings (FBGs) provide accurate, nonintrusive, and reliable remote measurements of temperature, strain, and pressure, and they are immune to electromagnetic interference. FBGs are extensively used in telecommunications, and their manufacture is now cost-effective. As sensors, FBGs find many industrial applications in composite structures used in the civil engineering, aeronautics, train transportation, space, and naval sectors. Tiny FBG sensors embedded in a composite material can provide in situ information about polymer curing (strain, temperature, refractive index) in an elegant and nonintrusive way. Great improvements in composite manufacturing processes such as resin transfer molding (RTM) and resin film infusion (RFI) have been obtained through the use of these sensors. They can also be used in monitoring the “health” of a composite structure and in impact detection to evaluate, for example, the airworthiness of aircraft. Finally, FBGs may be used in instrumentation as composite extensometers or strain rosettes, primarily in civil engineering applications.

Upper Air Measurements

2001 ◽  
Author(s):  
Fred V. Brock ◽  
Scott J. Richardson
Keyword(s):  
Doppler Radar ◽  
Longwave Radiation ◽  
Doppler Frequency ◽  
Cost Effective ◽  
Remote Sensors ◽  
Ground Station ◽  
Remote Measurements ◽  
In Situ Sensors ◽  
Excellent Spatial Resolution

Measurements of atmospheric properties become progressively more difficult with altitude above the surface of the earth, and even surface measurements are difficult over the oceans. First balloons, then airplanes and rockets, were used to carry instruments aloft to make in-situ measurements. Now remote sensors, both ground-based and satellite-borne, are used to monitor the atmosphere. In this context, upper air means all of the troposphere above the first hundred meters or so and, in some cases, the stratosphere. There are many uncertainties associated with remote sensing, so there is a demand for in-situ sensors to verify remote measurements. In addition, the balloon- borne instrument package is relatively inexpensive. However, it should be noted that cost is a matter of perspective; a satellite with its instrumentation, ground station, etc. may be cost-effective when the mission is to make measurements all over the world with good space and time resolution, as synoptic meteorology demands. Upper air measurements of pressure, temperature, water vapor, and winds can be made using in-situ instrument packages (carried aloft by balloons, rockets, or airplanes) and by remote sensors. Remote sensors can be classified as active (energy emitters like radar or lidar) or passive (receiving only, like microwave radiometers), and by whether they “look” up from the ground or down from a satellite. Remote sensors are surveyed briefly before discussing in-situ instruments. Profiles of temperature, humidity, density, etc. can be estimated from satellites using multiple narrow-band radiometers. These are passive sensors that measure longwave radiation upwelling from the atmosphere. For example, temperature profiles can be estimated from satellites by measuring infrared radiation emitted by CO2 (bands around 5000 μm) and O2 (bands around 3.4μm and 15μm) in the atmosphere. Winds can be estimated from cloud movements or by using the Doppler frequency shift due to some component of the atmosphere being carried along with the wind. An active sensor (radar) is used to estimate precipitation and, if it is a Doppler radar, determine winds. The great advantage of satellite-borne instruments is that they can cover the whole earth with excellent spatial resolution.

scholarly journals Stable, Ductile and Strong Ultrafine HT-9 Steels via Large Strain Machining

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2538 ◽  
Author(s):  
Osman El-Atwani ◽  
Hyosim Kim ◽  
Jonathan G. Gigax ◽  
Cayla Harvey ◽  
Berk Aytuna ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Large Strain ◽  
Cost Effective ◽  
Industrial Applications ◽  
Excellent Thermal Stability ◽  
Transmission Electron ◽  
Cost Effective Method ◽  
Dislocation Densities ◽  
Thermal Stability Of

Beyond the current commercial materials, refining the grain size is among the proposed strategies to manufacture resilient materials for industrial applications demanding high resistance to severe environments. Here, large strain machining (LSM) was used to manufacture nanostructured HT-9 steel with enhanced thermal stability, mechanical properties, and ductility. Nanocrystalline HT-9 steels with different aspect rations are achieved. In-situ transmission electron microscopy annealing experiments demonstrated that the nanocrystalline grains have excellent thermal stability up to 700 °C with no additional elemental segregation on the grain boundaries other than the initial carbides, attributing the thermal stability of the LSM materials to the low dislocation densities and strains in the final microstructure. Nano-indentation and micro-tensile testing performed on the LSM material pre- and post-annealing demonstrated the possibility of tuning the material’s strength and ductility. The results expound on the possibility of manufacturing controlled nanocrystalline materials via a scalable and cost-effective method, albeit with additional fundamental understanding of the resultant morphology dependence on the LSM conditions.

Preliminary Review of Physically Based Methodologies for Predicting the Strength of Visibly Damaged Composite Laminates

2010 ◽  
Vol 654-656 ◽  
pp. 2587-2591 ◽  
Author(s):  
Alex Harman ◽  
Andrew Litchfield ◽  
Rodney Thomson
Keyword(s):  
Residual Strength ◽  
Composite Laminates ◽  
Composite Structures ◽  
Prediction Method ◽  
Cost Effective ◽  
Preliminary Review ◽  
Management Guidelines ◽  
Compression After Impact ◽  
Physically Based

Approaches to detect, assess, monitor and repair damage in critical aircraft components fabricated from composite materials are essential for safe and cost effective operation. In metallic aircraft structures, it is common to leave some fractures in situ for a prescribed period until it is convenient to repair, provided strict inspection and verification processes are in place. Under current military aircraft structural management guidelines, visible damage to critical composite components requires either immediate repair or replacement. Much has been learnt about the behaviour of damaged composite structures, but further investigation is required to develop validated residual strength and life prediction tools. A preliminary review of an early physically based, residual strength prediction method was conducted. The accuracy of this method for use in predicting the strength of composite following a complex damage was tested by comparing the results with compression-after-impact test data for a composite laminate representative of F/A 18 fracture critical structure.

Signal Processing Enhanced Fiber Vibration Sensors

2013 ◽  
Vol 543 ◽  
pp. 302-305
Author(s):  
Daniele Tosi ◽  
Massimo Olivero ◽  
Alberto Vallan ◽  
Guido Perrone
Keyword(s):  
Signal Processing ◽  
Optical Fibers ◽  
Adaptive Filters ◽  
Spectral Estimation ◽  
Cost Effective ◽  
Fiber Sensors ◽  
High Frequencies ◽  
Vibration Sensors ◽  
Signal Processing Algorithms ◽  
Plastic Optical Fibers

The paper analyzes the feasibility of cost-effective fiber sensors for the measurement of small vibrations, from low to medium-high frequencies, in which the complexity of the measurement is moved from expensive optics to cheap electronics without losing too much performance thanks to signal processing algorithms. Two optical approaches are considered: Bragg gratings in standard telecom fibers, which represent the most common type of commercial fiber sensors, and specifically developed sensors made with plastic optical fibers. In both cases, to keep the overall cost low, vibrations are converted into variations of the light intensity, although this makes the received signal more sensitive to noise. Then, adaptive filters and advanced spectral estimation techniques are used to mitigate noise and improve the sensitivity. Preliminary results have demonstrated that the combined effect of these techniques can yield to a signal-to-noise improvement of about 30 dB, bringing the proposed approaches to the level of the most performing sensors for the measurement of vibrations.

scholarly journals A Review on LDH-Smart Functionalization of Anodic Films of Mg Alloys

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 536
Author(s):  
Mosab Kaseem ◽  
Karna Ramachandraiah ◽  
Shakhawat Hossain ◽  
Burak Dikici
Keyword(s):  
Industrial Applications ◽  
Mg Alloys ◽  
Anodic Films ◽  
Electrolytic Oxidation ◽  
Recent Developments ◽  
Plasma Electrolytic ◽  
Co Precipitation ◽  
Corrosive Environments ◽  
Double Hydroxide

This review presents an overview of the recent developments in the synthesis of layered double hydroxide (LDH) on the anodized films of Mg alloys prepared by either conventional anodizing or plasma electrolytic oxidation (PEO) and the applications of the formed composite ceramics as smart chloride traps in corrosive environments. In this work, the main fabrication approaches including co-precipitation, in situ hydrothermal, and an anion exchange reaction are outlined. The unique structure of LDH nanocontainers enables them to intercalate several corrosion inhibitors and release them when required under the action of corrosion-relevant triggers. The influences of different variables, such as type of cations, the concentration of salts, pH, and temperature, immersion time during the formation of LDH/anodic film composites, on the electrochemical response are also highlighted. The correlation between the dissolution rate of PEO coating and the growth rate of the LDH film was discussed. The challenges and future development strategies of LDH/anodic films are also highlighted in terms of industrial applications of these materials.

scholarly journals Fabrication of a liquid cell for in situ transmission electron microscopy

Microscopy ◽  
2020 ◽  
Author(s):  
Xiaoguang Li ◽  
Kazutaka Mitsuishi ◽  
Masaki Takeguchi
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cost Effective ◽  
Production Method ◽  
Microscopy Imaging ◽  
Transmission Electron ◽  
In Situ Electron Microscopy ◽  
Liquid Cell ◽  
Si Wafer

Abstract Liquid cell transmission electron microscopy (LCTEM) enables imaging of dynamic processes in liquid with high spatial and temporal resolution. The widely used liquid cell (LC) consists of two stacking microchips with a thin wet sample sandwiched between them. The vertically overlapped electron-transparent membrane windows on the microchips provide passage for the electron beam. However, microchips with imprecise dimensions usually cause poor alignment of the windows and difficulty in acquiring high-quality images. In this study, we developed a new and efficient microchip fabrication process for LCTEM with a large viewing area (180 µm × 40 µm) and evaluated the resultant LC. The new positioning reference marks on the surface of the Si wafer dramatically improve the precision of dicing the wafer, making it possible to accurately align the windows on two stacking microchips. The precise alignment led to a liquid thickness of 125.6 nm close to the edge of the viewing area. The performance of our LC was demonstrated by in situ transmission electron microscopy imaging of the dynamic motions of 2-nm Pt particles. This versatile and cost-effective microchip production method can be used to fabricate other types of microchips for in situ electron microscopy.

Cost effective in-situ methane enrichment for chicken farm biogas system

2021 ◽  
pp. 100773
Author(s):  
Kamoldara Reansuwan ◽  
Rotsukon Jawana ◽  
Saoharit Nitayavardhana ◽  
Sirichai Koonaphapdeelert
Keyword(s):  
Cost Effective ◽  
Chicken Farm

scholarly journals Remote Reflectivity Sensor for Industrial Applications

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1301
Author(s):  
Federico Cavedo ◽  
Parisa Esmaili ◽  
Michele Norgia
Keyword(s):  
Low Cost ◽  
Cost Effective ◽  
Industrial Applications ◽  
Interference Immunity ◽  
Surface Reflection ◽  
Measurement Systems ◽  
Digital Detector ◽  
Reflected Light ◽  
Surface Optical ◽  
Diffused Light

A low-cost optical reflectivity sensor is proposed in this paper, able to detect the presence of objects or surface optical properties variations, at a distance of up to 20 m. A collimated laser beam is pulsed at 10 kHz, and a synchronous digital detector coherently measures the back-diffused light collected through a 1-inch biconvex lens. The sensor is a cost-effective solution for punctual measurement of the surface reflection at different distances. To enhance the interference immunity, an algorithm based on a double-side digital baseline restorer is proposed and implemented to accurately detect the amplitude of the reflected light. As results show, the sensor is robust against ambient light and shows a strong sensitivity on a wide reflection range. The capability of the proposed sensor was evaluated experimentally for object detection and recognition, in addition to dedicated measurement systems, like remote encoders or keyphasors, realized far from the object to be measured.

scholarly journals Influence of Hydrogeochemistry on Tunnel Drainage in Evaporitic Formations: El Regajal Tunnel Case Study (Aranjuez, Spain)

2021 ◽  
Vol 13 (3) ◽  
pp. 1505
Author(s):  
Ignacio Menéndez Pidal ◽  
Jose Antonio Mancebo Piqueras ◽  
Eugenio Sanz Pérez ◽  
Clemente Sáenz Sanz
Keyword(s):  
High Speed ◽  
Civil Engineering ◽  
Saturation Index ◽  
The Subject ◽  
Under Construction ◽  
Underground Flow ◽  
Very High ◽  
Over Time

Many of the large number of underground works constructed or under construction in recent years are in unfavorable terrains facing unusual situations and construction conditions. This is the case of the subject under study in this paper: a tunnel excavated in evaporitic rocks that experienced significant karstification problems very quickly over time. As a result of this situation, the causes that may underlie this rapid karstification are investigated and a novel methodology is presented in civil engineering where the use of saturation indices for the different mineral specimens present has been crucial. The drainage of the rock massif of El Regajal (Madrid-Toledo, Spain, in the Madrid-Valencia high-speed train line) was studied and permitted the in-situ study of the hydrogeochemical evolution of water flow in the Miocene evaporitic materials of the Tajo Basin as a full-scale testing laboratory, that are conforms as a whole, a single aquifer. The work provides a novel methodology based on the calculation of activities through the hydrogeochemical study of water samples in different piezometers, estimating the saturation index of different saline materials and the dissolution capacity of the brine, which is surprisingly very high despite the high electrical conductivity. The circulating brine appears unsaturated with respect to thenardite, mirabilite, epsomite, glauberite, and halite. The alteration of the underground flow and the consequent renewal of the water of the aquifer by the infiltration water of rain and irrigation is the cause of the hydrogeochemical imbalance and the modification of the characteristics of the massif. These modifications include very important loss of material by dissolution, altering the resistance of the terrain and the increase of the porosity. Simultaneously, different expansive and recrystallization processes that decrease the porosity of the massif were identified in the present work. The hydrogeochemical study allows the evolution of these phenomena to be followed over time, and this, in turn, may facilitate the implementation of preventive works in civil engineering.

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