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The designs of the natural
Published in Martyn Dade-Robertson, Living Construction, 2020
If my students are sceptical about the machine analogy in theory, they wholeheartedly reject it after a few days at the laboratory bench. Bacterial cells work at length scales which, most of the time, are not visible to the naked eye. However, in a single agar plate experiment, we can be dealing with more cells than there are humans on earth. Neither of these scales is perceivable or easily imaginable. Bacterial cells are also not nearly as programmable as robot arms, and they have much greater autonomy and range of behaviour. They might live or die, and they are sensitive to even small changes to their environment. On one day, they will grow happily; on another, they will decline radically for reasons we can’t easily explain. If our robot arm were as temperamental, we would send it back to the manufacturer. Cells are not machines; they have a different ‘nature’.
Robot’s Sensors and Instrumentation
Published in Jitendra R. Raol, Ajith K. Gopal, Mobile Intelligent Autonomous Systems, 2016
The infrared (IR) radiation exists in the electromagnetic spectrum and is not visible to the naked eye (it has a longer wavelength than visible light; see Figure 8.4). The IR sensors are a type of thermal sensor. IR sensors commonly house a pyroelectric crystal formed as thin-plate capacitors which produce a surface electric charge when the device is exposed to IR radiation. Pyroelectric materials generate temporary change in energy when heated or cooled. The electric charge causes a voltage drop in the capacitor. The charge itself is induced as pyroelectric crystals which inherently have spontaneous electrical polarization—IR changes the polarization which in turn causes induction of charges. When the amount of the radiation falling on the crystal changes, the amount of charge that can be measured accordingly gets affected. There usually is a preamplifier circuit built in as the high-impedance source of the pyroelectric set-up that produces very little current voltage follower. These IR sensors are very useful for night vision for mobile robots. The IR sensors can also be used in conjunction with vision sensors as well as sonars in the multi-sensor data fusion architecture to enhance the predictive accuracy of the robot’s overall vision system and can be very useful for avoiding multiple obstacles moving in an uncertain fashion in the robot’s environment.
Autonomous Vehicles for Infrastructure Inspection Applications
Published in Diego Galar, Uday Kumar, Dammika Seneviratne, Robots, Drones, UAVs and UGVs for Operation and Maintenance, 2020
Diego Galar, Uday Kumar, Dammika Seneviratne
Thermography, or thermal imaging, is photography using a camera that captures IR light rather than the visible light captured by a standard camera. IR rays are outside the visible spectrum and are invisible to the naked eye. All objects that are warmer than absolute zero (−273°C) emit IR light. The warmer an object is, the more IR light it emits. IR cameras record the amount of IR light and transfer it into temperature, which is indicated by the scale bar or thermogram.
On the Relation between the Astronomical and Visual Photometric Systems in Specifying the Brightness of the Night Sky for Mesopically Adapted Observers
Published in LEUKOS, 2022
Irena Fryc, Salvador Bará, Martin Aubé, John C. Barentine, Jaime Zamorano
The use of the MES-2 visual-performance-based mesopic photometry system seems appropriate for reporting naked-eye observations of the night sky. Most of these observations involve the extensive use of peripheral vision both for overall nightscape contemplation and for event detection and identification, as it occurs in visual monitoring of meteoroid showers or in the observation of deep-sky objects with “averted” vision, aspects that were specifically taken into account for the definition of the MES-2. Only a few naked-eye astronomical tasks are carried out resorting almost exclusively to foveal vision as, e.g., variable star brightness monitoring using the comparative Argelander method (Yendell 1905). Note that for foveal vision tasks involving brightness matching the photopic sensitivity function provides an adequate evaluation of luminance across the whole adaptation range, due to the relative lack of rods (and S-cones) in the foveal region. For the remaining tasks, however, the combined contribution of rods and cones in the mesopic range needs to be accounted for by means of a suitable performance-based mesopic photometric system.
Comparative in Situ Study of Nanolime, Ethyl Silicate and Acrylic Resin for Consolidation of Wall Paintings with High Water and Salt Contents at the Chapter Hall of Chartres Cathedral
Published in International Journal of Architectural Heritage, 2020
Laura Normand, Stéphanie Duchêne, Véronique Vergès-Belmin, Claire Dandrel, David Giovannacci, Witold Nowik
According to Figure 6, gypsum is the only salt able to crystallise when the RH is higher than 60%, either at 5°C or 20°C. Indeed, only gypsum superficial crystallisations were identified by XRD (Dandrel 2017) and removed before the study. Between 50% and 60% RH, sodium nitrate can possibly crystallise too. Given that the T and RH recorded during the study fluctuated respectively in the range of 5–20°C and 60–95% RH, there should not be any crystallized salts except gypsum on the east wall. Below 60% RH, the risk of crystallisation of different salts would increase. Naked eye, digital microscope observations and FTIR. Two parameters were assessed: whitening and gloss, through comparison of microscopic and naked eyes views. On the reference area no change was observed at three and nine months. After the application of the nanolime Calosil IP5, a white haze appeared immediately. A cellulose poultice moistened with distilled water was applied through a Japanese paper and removed after drying, but rare white spots on the red and orange part of the tested area remained. A slight white haze appeared on the dark red part less than one hour after the application of the ethyl silicate. This area did not show any gloss change. No further change of the slight white haze was observed on the dark red part even fifteen months after consolidation. Primal E330S did not induce any white haze or gloss change. Very small and scarce white spots were visible in the dark red area nine and fifteen months after the last application of the Primal E330S — without any lifting of the paint layer. They were also observed rarely on the east wall painting apart from the studied areas. FTIR analyses (Figure 8) show gypsum, calcite and some acrylic resin.
Substrates and preparation layers under the wall paintings of the St George’s Cathedral (1119 CE) at Veliki Novgorod
Published in Surface Engineering, 2023
Alessandra R. G. Giumlia-Mair, Vladimir V. Sedov, Olga Etinhof
All samples have been examined with the naked eye, optical magnification devices, a digital microscope, and an optical microscope (henceforth OM). This kind of investigation is very important and allows a first screening of the materials. In the laboratory, we used several microscopes but mainly an Olympus BX51. When we were dealing with in situ paintings, as for example in the tower of the St. George’s Cathedral, we employed a digital Proscope with 50 x magnification and a portable Levenhuk with variable magnification.