Signal tower control was made by logical conditions placed in macropump. For those who are less familiar I would like to explain that the macropump is a macro, that is running constantly (while loop) in the Mach3 programbackground. Thanks to this macropump feature we can control the signal tower automatically as the logical conditions are all the time verfied and done optionally.
The Ritz-Carlton Residences Portland are situated atop a stunning 35 story mixed-use tower that will offer magnificent views of the city and will become a landmark in this dynamic Pacific Northwest city.
Made from tubular steel, the tower supports the structure of the turbine. Towers usually come in three sections and are assembled on-site. Because wind speed increases with height, taller towers enable turbines to capture more energy and generate more electricity. Winds at elevations of 30 meters (roughly 100 feet) or higher are also less turbulent.
The nacelle sits atop the tower and contains the gearbox, low- and high-speed shafts, generator, and brake. Some nacelles are larger than a house and for a 1.5 MW geared turbine, can weigh more than 4.5 tons.
In the end, NIST released final versions of the 43 reports on the WTC towers, totaling some 10,000 pages, on October 26, 2005. NIST released final versions of the three reports on WTC 7, totaling about 1,000 pages, on November 25, 2008.
In the field of structural health monitoring , great benefits have been introduced by terrestrial radar interferometry with a real aperture antenna (also referred to as TInRAR), being such a technique contactless, non-destructive, non-sensitive to dust, and able to detect displacements with an accuracy of tenths of millimeters [8,9,10,11,12,13,14,15,16,17]. Moreover, several authors have introduced benefits in the dynamic surveying of historical buildings and towers from high-speed real aperture radar interferometry under static and dynamic loads, for instance in the procedures devoted to the static and seismic vulnerability analyses [1,18,19,20,21]. Based on sampling rates up to 200 Hz, the TInRAR allows to measure also the fast vibrations of the structure induced by dynamic loadings and to perform the structural dynamic identification in operational conditions. In addition, the use of TInRAR instrumentation can also reveal possible damage to the structures that changes their physical properties and the modal behavior with respect to theoretical responses provided, for instance, by a finite element (FE) model . Some limitations have to be mentioned also for ground-based real-aperture techniques. Basically, they can provide range resolution, and thus, displacements can be detected on the slant direction only. For this reason, geometric aspects of the surveys with TInRAR instrumentation must be carefully designed to detect the structural displacement efficiently.
The available literature has proven in a few case studies the reliability of TInRAR techniques to measure masonry tower oscillations caused by natural excitations or bell ringing, and also by setting the instrumentation 1-km away from the monitored structures . Rarely monitoring data collected from older TInRAR radar sensors has been validated with dynamic data provided by traditional sensors (such as velocimeters or accelerometers) under natural or induced excitations [23,24]. Such a validation procedure needs an accurate design of the experimental tests, a proper definition of the sensor positions in order to allow for a reliable comparison of results, and suitable integration operations when comparing displacements with quantities measured from other types of sensors. Indeed, the integration procedure introduces trends that have to be removed without altering the frequency content of the obtained time-series. The original contribution of this research lies in implementing a rigorous approach that takes into account the abovementioned key issues to provide a reliable validation of a TInRAR-based approach in comparison to a traditional sensors-based approach. The available literature, indeed, often shows TInRAR results and potentialities without a direct comparison to measuring systems based on contact sensors, which present many advantages in terms of quality and reliability of results.
This paper discusses the performances, benefits, and drawbacks of the use of TInRAR technology for structural monitoring of ancient masonry towers. The novelty of the research lies in assessing the usefulness, and consequently the reliability of the provided results, both in integration to traditional sensors and as an alternative in case their use is not feasible. The accuracy of results was evaluated through the comparison of the displacement measured by the radar interferometer with those obtained after a double integration from two types of accelerometers directly installed on the tower. This allowed performing the validation of radar results. The case study was represented by a masonry tower of great historical interest, the tower of Saint Prospero (Reggio Emilia, Northern Italy). Skilled ringers played traditional melodies by moving the tower bells during a famous cultural event held in the historical center of Reggio Emilia. During such an event, the players perceive remarkable displacements that are very difficult to quantify. In this frame, a monitoring of the dynamic behavior of the masonry tower was performed by using an array of accelerometers located at different heights and a TInRAR instrument, manufactured by IDS GeoRadar Srl (IBIS-FS model, a microwave interferometry-based system for remote static and dynamic monitoring). The performances of the TInRAR technology were evaluated both in operational conditions (that is when the tower was subjected to natural excitations) and during a bell concert.
The Tower of Saint Prospero and the nearby Basilica, Reggio Emilia (Northern Italy): (a) location map, (b) picture of the monuments from the adjacent square, (c) internal geometry of the bell tower.
Design of the dynamic monitoring test with the terrestrial radar interferometry with a real aperture antenna (TInRAR) technology: (a) picture of the IBIS-FS radar interferometer, manufactured by IDS GeoRadar Srl, and the setup during data collection; (b) radar positioning with knowledge of the LoS (line of sight) misalignment with respect to the defined coordinate system; (c) geometry setup of the radar with respect to the tower with identifications (location and naming) of the range bins (RBs) selected for analyzing displacement time-series. The principle for computing the radar displacement is also represented in the picture, being d the real displacement and dr the radial displacement (size is exaggerated on purpose).
Displacements of the accelerometer-based measuring systems were calculated from the recorded accelerations through a double numerical integration, as reported in Section 4.2. Figure 10 plots the displacement of the level L4 in the x- and y-directions during a few seconds of high excitation due to the bells. As expected, the tower oscillated mainly in the x-direction although non-negligible oscillations were observed also in the y-direction. Indeed, the direction of maximum displacement of the tower was tilted 7.05 from the x-direction. Figure 10 also shows the misalignment of the measuring direction of the terrestrial radar interferometer (14.22) with respect to the x-direction. To compare the results of the accelerometers (that measure in the x- and y-directions) with those obtained from the TInRAR, accelerations were projected on the same measuring directions of the TInRAR.
Displacement along the height of the tower at three time instants: (a) t = 30.8 s, (b) t = 63.5 s, (c) t = 92.9 s. Black lines: MEMS accelerometers; blue lines: piezoelectric accelerometers; red lines: TInRAR.
(a) Displacements and (b) RMS displacement traces of level L5. Black lines: MEMS accelerometer M6; red lines: TInRAR, range bin 53. Note that in this case, the accelerometer measured the displacement of the wooden frame supporting the bells and not the displacement of the tower itself.
The main drawback related to these differences is evident when the complete deformed shape of the tower is computed for a selected time instant. For example, Figure 13 shows the displacement of the measuring points along the height of the tower at three different time instants. As mentioned before, the displacements of the two accelerometer-based measuring systems are consistent with each other while the TInRAR underestimates or overestimates the results depending on the considered level as well as the time instant. Indeed, the deformed shape obtained from the TInRAR presents abnormalities along the height of the tower, which are not present in those obtained from the accelerometers.
The displacements of the level L5 obtained from the MEMS accelerometer M6 and TInRAR are compared in Figure 14. In this case, the significant discrepancy between results is because the MEMS accelerometer was placed on the wooden frame supporting the bells instead of on the tower, while the TInRAR measured the displacement of the tower itself. Indeed, the wooden frame is more flexible than the tower and suffers from higher displacements due to the bells. Moreover, Figure 15 shows the displacement measured from the TInRAR at the top of the tower (40.00 m). At that level, the corresponding structural response measured from the accelerometers was not available because of accessibility problems. In general, results show that the maximum displacement caused by the bell swinging goes up to about 5 mm.
Figure 15 also points out a relevant property of the radar interferometer: the capability to provide information about the displacements at the top of the tower, i.e., where the maximum displacement occurs. In that position, in fact, it is often really hard or even impossible to install an accelerometer due to accessibility problems. 041b061a72