Top-down contact angle measurements have been validated and confirmed to be as good if not more reliable than side-based measurements. A range of samples, including industrially relevant materials for roofing and printing, has been compared. Using the top-down approach, mapping in both 1-D and 2-D has been demonstrated. The method was applied to study the change in contact angle as a function of change in silver (Ag) nanoparticle size controlled by thermal evaporation. Large area mapping reveals good uniformity for commercial Aspen paper coated with black laser printer ink. A demonstration of the forensic and chemical analysis potential in 2-D is shown by uncovering the hidden CsF initials made with mineral oil on the coated Aspen paper. The method promises to revolutionize nanoscale characterization and industrial monitoring as well as chemical analyses by allowing rapid contact angle measurements over large areas or large numbers of samples in ways and times that have not been possible before.
Seascapes are large, multiple‐use marine areas, defined scientifically and strategically, in which government authorities, private organizations, and other stakeholders cooperate to conserve the diversity and abundance of marine life and promote human well‐being. This approach has been applied by global nonprofit partnerships in five seascapes across eight countries and has drawn on the practical experience of more than 250 partners over 15 years. These experiences have helped define the Seascape approach, consisting of nine essential elements, for achieving effective ocean governance and management from local to regional levels. Lessons learned relate to using integrated planning frameworks, community‐led and locally owned initiatives, and a network of partners and a “backbone” organization for effective Seascape planning and design; promoting diversification in funding sources, private sector engagement, and the transition of nonprofit roles to ensure durability of a Seascape; and ensuring Seascape outcomes are measured through robust monitoring and evaluation frameworks and communicated effectively. Seascapes are unique in their ability to create a pathway toward sustainable development. To ensure support and amplification of the approach, they must align with diversified funding opportunities and global priorities outlined in international United Nations conventions focused on sustainable development and ocean health.
In this paper, a new multiparametric optical fiber transducer is presented for simultaneous temperature and vibration sensing in hydroelectric high-power generators. The optical transducer holds three multiplexed fiber Bragg gratings (FBGs) as the sensing elements. In the transducer, each FBG can simultaneously measure temperature and vibration independent of the other FBGs. With a temperature characterization, it is possible to determine the thermal stability (1.5 °C) over the test duration and the thermal sensitivity of the packaged FBGs 10 pm/°C. Moreover, the vibration characterization tests rely on an impact hammer and a shaker. With the impact hammer test, the transducer package natural frequency of 565 Hz is determined. The shaker performed a frequency sweep over 5 Hz to 1 kHz, and the transducer mean vibration sensitivity is found to be 7.2 pm/g. Subsequently, the power plant installation is performed using six transducers. They are installed into six different windings slots to sense stator bars of a 370-MVA hydroelectric generator. With this instrumentation, 23 h of simultaneous vibration and temperature sensing is carried out. All the FBGs used to monitor vibration were able to monitor the frequency of mechanical vibration (2 Hz) and electromagnetic vibration (120 Hz) of the generator. During the power plant test, the machine was turned OFF due to a failure and all the FBGs were able to measure the temperature as well as vibration changes caused by the machine shutdown.
In this paper, we used infrared light in the range of 8–12 μm to develop and test an optical imaging system to detect air bubbles flowing in oil. The system basically comprises a broadband light source and a 31 × 32 thermopile array to generate images. To analyze the effects related to light absorption, reflection, and refraction on air-oil boundaries, a numerical model was developed and the predominance of the refraction instead of the absorption in bubbles with diameters below a certain critical value was observed. The IR region of the electromagnetic spectrum has both optical and thermic behavior. To understand the limits of each effect on the oil flow imaging, a study of the influence of temperature variation on the petroleum optical detection was performed. The developed optical imaging system allowed the detection of air flow in static oil and in oil-air two-phase flow. With the presented system, it was possible to achieve images through up to 12 mm of oil volumes, but this may be enhanced by the use of optimized IR sources and detectors.
This article presents two in vivo instrumentation techniques to study the different types of gait of horses performing athletics using fiber Bragg gratings (FBG). These techniques can be used as an auxiliary tool in the early diagnosis of injuries related to the horse’s locomotor system, mainly in the distal portion of the digit, one of the most common causes of retirement when they are athletes. Therefore, the first technique presented consists of the fixation of FBGs without encapsulation, directly on the dorsal wall of the hoof in each of the limbs. In the second technique presented, the FBG sensor is encapsulated in a prototype developed using a composite material reinforced with carbon fiber in a horseshoe shape. The second technique is associated with digital image processing (DIP) for better visualization of the deformation and compression forces that act upon the limbs. The first method showed sensitivity to detection of the digit compression against the ground, being able to identify walking patterns. The second technique, with the encapsulated sensor elements, also allows the capture of characteristic signals of gait, such as step walk, trot, and gallop under training conditions. Both, FBG sensor interrogation and DIP, analysis techniques have proven good performance and promising results for the clinical and biomechanical study and medical evaluations of horses even during dynamic training and competitions.
In this paper field measurements are carried out using a distributed acoustic sensing system (DAS) for the identification of horse gait. The DAS system has a spatial resolution of 1 m, frequency range of 1-5 kHz and the fiber length is of about 70 m. The optical fiber cable lays down into trench of 15 cm of depth. Several measurements are also carried out in order to fully understand the measuring capacity of the system, including a 2 kg calibrated impact hammer and a small controlled blast of 12.6 Pa of air pressure. Results demonstrate the capacity to measure soil mechanical waves speed of 171 m/s for the impact hammer tests and sound speeds in air of about 366 m/s for the controlled blast tests. The experiments involving horses allowed the identification of three distinct horse gait patterns: step, trot and gallop, as well the horse speed in each gait with SNR about 30 dB.