Vatell (United States)

Abstract Satellite Interferometric Synthetic Aperture Radar (InSAR) is an accredited technology used in many fields in the last decades, but represents a relatively new technology for civil infrastructures monitoring. It allows to measure displacement along the line of sight (LOS) of the sensor with a millimetric precision. This study was conducted to show the potential of SAR sensors, mounted on satellite platforms, in detecting displacements induced by the excavations of tunnels in urban areas. Advances in remote sensing, such as the development of Multi‐Temporal InSAR algorithms, have overcome the limit of InSAR due to spatial‐temporal decorrelation of the phase measurement, thus improving the precision of the outcomes. Here the COSMO‐SkyMed satellite constellation acquired data over a small area in the city of Naples, affected by the excavation of twin tunnels. Data were processed with the SARPROZ software, while tunnel induced settlement were predicted with empirical methods. To allow comparison, displacements along LOS were projected in the vertical plane. Results indicate a good agreement between the monitored data and the predicted profile of settlement, further confirming the potential of MT‐InSAR in detecting displacements induced by tunneling excavation in urbanized area.

<div class="section abstract"><div class="htmlview paragraph">A multi-position 4-stroke piston engine utilizing a novel rotary valve system was developed for handheld outdoor power equipment applications such as chainsaws, brush cutters, and string trimmers. The purpose of the project was to create a low-emission 4-stroke engine with 2-stroke performance levels including high RPM limits and power output. This was accomplished using a rotary valve system in lieu of the typical poppet valves of traditional 4-stroke engines. The prototype was then incorporated into a functional product for overall performance evaluation.</div><div class="htmlview paragraph">Three prototype 45cc rotary valve engines were developed and tested in both real-world usage and on laboratory engine dynamometers to measure power output and emissions levels. The rotary valve system provided the ability to achieve high RPM limits without the risk of valve float, delivered improved volumetric efficiency, and exhibited lower vibration and noise levels with improved power density over traditional 4-stroke valvetrains. Additionally, the total valvetrain part count and complexity was greatly reduced over poppet valve cylinder head designs.</div><div class="htmlview paragraph">This paper will discuss the goals of this exercise and the relative performance of the final prototypes.</div></div>

This paper demonstrates a calorimetric procedure for calibrating high-heat-flux sensors. The results are in agreement with calibrations obtained using black-body radiation. However, the proposed method has the potential of being more accurate than traditional approaches. This new procedure calibrates sensors to measure correctly under conditions of concentrated solar radiation. At present, the thermal balance calibration technique in the laboratory is limited to solar irradiances of approximately 100 kW m−2. The next step is to demonstrate this methodology to higher irradiances under non-laboratory conditions in the CIEMAT solar furnace at Plataforma Solar de Almería.

The performance characteristics of a heat flux microsensor have been measured and analyzed. This is a new heat flux gage system that is made using microfabrication techniques. The gages are small, have high frequency response, can measure very high heat flux, and output a voltage directly proportional to the heat flux. Each gage consists of a thin thermal resistance layer sandwiched between many thermocouple pairs forming a differential thermopile. Because the gage is made directly on the measurement surface and the total thickness is less than 2µm, the presence of the gage contributes negligible flow and thermal disruption. The active surface area of the gage is 3 mm by 4 mm, with the leads attached outside this area to relay the surface heat flux and temperature signals. Gages were made and tested on glass and silicon substrates. The steady and unsteady response was measured experimentally and compared with analytical predictions. The analysis was performed using a one-dimensional, transient, finite-difference model of the six layers comprising the gage plus the substrate. Steady-state calibrations were done on a convection heat transfer apparatus and the transient response was measured to step changes of the imposed radiative flux. As an example of the potential capabilities, the time-resolved heat flux was measured at a stagnation point with imposed freestream turbulence. A hot-film probe placed outside the boundary layer was used to provide a simultaneous signal showing the corresponding turbulent velocity fluctuations.