256 research outputs found
Lidar and radar measurements of the melting layer: Observations of dark and bright band phenomena
No full textMulti-wavelength lidar measurements in the melting layer revealing the presence of dark and bright bands have been performed by the University of BASILicata Raman lidar system (BASIL) during a stratiform rain event. Simultaneously radar measurements have been also performed from the same site by the University of Hamburg cloud radar MIRA 36 (35.5 GHz), the University of Hamburg dual-polarization micro rain radar (24.15 GHz) and the University of Manchester UHF wind profiler (1.29 GHz). Measurements from BASIL and the radars are illustrated and discussed in this paper for a specific case study on 23 July 2007 during the Convective and Orographically-induced Precipitation Study (COPS). Simulations of the lidar dark and bright band based on the application of concentric/eccentric sphere Lorentz-Mie codes and a melting layer model are also provided. Lidar and radar measurements and model results are also compared with measurements from a disdrometer on ground and a two-dimensional cloud (2DC) probe on-board the ATR42 SAFIRE. Measurements and model results are found to confirm and support the conceptual microphysical/scattering model elaborated by Sassen et al. (2005).TelecommunicationsElectrical Engineering, Mathematics and Computer Scienc
Ground-based remote sensing of wind, temperature and aerosol backscattering in an urban environment during different atmospheric stability conditions
No full textThe diurnal evolution of the urban boundary layer over the central area of Rome was observed by the simultaneous and co-located operation of a Doppler sodar, a microwave radiometer and a dual polarization lidar. The Doppler sodar was configured to provide a wind profile up to about 800 m, and a time-height picture of the thermal structure of the urban boundary layer. A microwave radiometer provided a temperature profile up to 600 m with a height resolution of 50 m. The lidar provided profiles of the aerosol backscattering up to about 7-10 km with 30 m height resolution. The experiment was conducted for several days in the year 1998 during day and night with clear sky and low wind. The aerosol profiles in the urban troposphere appear linked to stability conditions in the lower layers and strong pollution. The presence of aerosols, typically in the afternoon hours at heights up to 2-3 km, can be related to a relatively high mixed layer. Such layer is caused by free convection as indicated by the Richardson number, estimated by the temperature and wind data. Some typical case studies are discussed. (C) 2001 Elsevier Science Ltd. All rights reserved
Production systems, local labour market and the geographical distribution of some immigrant communities in Italy: initial empirical evidence
No full textTowards intelligent robotic sole deburring: From burrs identification to path planning
No full textToday, intelligent robotic manufacturing systems are reshaping the production industry. Using robots as actuators, multi-source sensors for perception, and Artificial Intelligence (AI) as decision-making systems, they can perform routine manufacturing tasks, surpassing the capabilities of traditional hard-programmed Computer Numerical Control (CNC) machinery. One specific challenge in footwear manufacturing is sole deburring, traditionally done manually by skilled workers. This paper focuses on developing a robust path-planning pipeline, comprising vision-based and Learning from Demonstrations (LfD) modules for autonomous deburring of soles. The vision-based module exploits Deep Learning (DL) techniques to handle key challenges such as precise segmentation of different soles types across diverse scenarios despite potential occlusions. Additionally, a novel method for burrs identification has been developed leveraging image processing and optimization techniques. Determining the optimal cutting tool orientation during sole deburring relies on human experience. The LfD module aims to impart this knowledge to the robot from videos of expert demonstrations, requiring adaptability to every new incoming sole that needs deburring. Experimental results showcase the method's performance and flexibility, underlining the potential to advance the field of the proposed approach
Lidar observations of polar stratospheric clouds at the South Pole .2. Stratospheric perturbed conditions, 1992 and 1993
No full textObservations of polar stratospheric clouds (PSCs), carried out at the Amundsen Scott South Pole Station by lidar from May 1992 through October 1993, are reported and compared with previously obtained results. At that time the Antarctic stratosphere was loaded with sulfuric acid aerosol due to the eruptions of Mount Pinatubo, primarily, and of Mount Hudson. The seasonal evolution of the backscatter profiles has been investigated in relation to the presence of the volcanic aerosol and to the processes of PSC formation, particle sedimentation, and dehydration. During the first winter after the eruptions the PSC activity was more intense than in the following year, particularly above 12.5 km, where the amount of volcanic aerosol was larger in 1992 than in 1993. At lower altitudes the volcanic aerosol loading as well as the PSC phenomenon were comparable during the 2 years. No substantial changes in the signal due to the volcanic aerosol has been observed comparing the backscattering profiles before and after the PSC periods (June–September), except for a downward shift, attributed to the subsidence of the air inside the polar vortex. It is concluded that only a small fraction of the aerosol particles, probably those with the largest radii, were involved in the nucleation of PSC particles
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