86,521 research outputs found
Optimized parachute recovery systems for remote piloted aerial systems
No full textThe new RPAS (remotely piloted aerial systems) are mostly video cameras with wings whose ownership isn't enshrined in any constitution. Rulers are rushing to do regulate the lack of safety and accountability for RPAS. In Italy ENAC (aviation authority) legislated against random acts of stupidity and probable failures. For the current year of 2015, there is a forecast to sell $1bn worth of RPAS product. For these reasons the installation of RPS (Recovery Parachute System) on commercial RPAS is particularly interesting. A few RPS manufacturers have manufactured specific RPS systems for "drones" both rotary and fixed wing. However, these systems are designed with the same criteria of manned aerial vehicle. This paper demonstrates that the design criteria of RPAS are sensibly different from other applications. In particular the rate of descent during recovery should be reduced from 6m/s to 2m/s. This fact poses new challenges in parachute design. In fact RPS mass depends on parachute diameter that increases with low descent rates. This paper demonstrates that it is possible to design effectively RPS for RPAS up to 80kg by using nonwoven fabric in parachutes. In this way the RPS mass is a small fraction of the RPAS one. Deployment systems are not a problem for RPAS since masses are extremely small and the power necessity are accordingly limited
Airborne concentrations of chrysotile asbestos in serpentine quarries and stone processing facilities in Valmalenco, Italy
No full textAsbestos may be naturally present in rocks and soils. In some cases, there is the possibility of releasing asbestos fibres into the atmosphere from the rock or soil, subsequently exposing workers and the general population, which can lead to an increased risk of developing asbestos-related diseases. In the present study, air contaminated with asbestos fibres released from serpentinites was investigated in occupational settings (quarries and processing factories) and in the environment close to working facilities and at urban sites. The only naturally occurrence of asbestos found in Valmalenco area was chrysotile; amphibole fibres were never detected. An experimental cut-off diameter of 0.25 μm was established for distinguishing between Valmalenco chrysotile and antigorite single fibres using selected area electron diffraction analyses. Air contamination from chrysotile fibres in the examined occupational settings was site-dependent as the degree of asbestos contamination of Valmalenco serpentinites is highly variable from place to place. Block cutting of massive serpentinites with multiple blades or discs and drilling at the quarry sites that had the highest levels of asbestos contamination generated the highest exposures to (i.e. over the occupational exposure limits) asbestos. Conversely, working activities on foliated serpentinites produced airborne chrysotile concentrations comparable with ambient levels. Environmental chrysotile concentrations were always below the Italian limit for life environments (0.002 f ml(-1)), except for one sample collected at a quarry property boundary. The present exposure assessment study should encourage the development of an effective and concordant policy for proper use of asbestos-bearing rocks and soils as well as for the protection of public health
Studio del rischio cancerogeno nel comparto lapideo - Estrazione e lavorazione di pietre ornamentali - Il problema della silice libera cristallina
No full textOccupational exposure and ambient air contamination by naturally occurring asbestos in Valmalenco (Italy)
No full textBackground and Aims: asbestos fibers naturally present in rocks and soils can be released into the atmosphere by
occupational and other human activities, as well as by meteorological agents. The aim of this work was the evaluation of the
occupational exposure levels and ambient concentrations of airborne fibers of naturally occurring asbestos (NOA) in quarries
and processing facilities of Valmalenco serpentinites, in the neighbourhood of the facilities and in the nearest urban centres.
Methods: occupational exposures to NOA were studied through personal and static monitoring carried out during the more
critical working activities. An analytical protocol composed by coupled TEM-SAED and SEM-EDS was specifically developed in
order to improve specificity thanks to the crystallographic discrimination between chrysotile and other polymorphs. Airborne
asbestos fiber concentrations were measured by SEM-EDS and only WHO fibers were counted according to the WHO criteria
(length > 5 μm, diameter 3).
Results: air contamination from chrysotile fibers (amphiboles were never detected) in the selected occupational and life
environments was site-dependent, as the degree of asbestos contamination of Valmalenco serpentinites is highly variable from
place to place. Working activities associated with the highest exposures and airborne contaminations included cutting of nonfoliated
serpentinites with multiple blades or discs and drilling at quarries located in the area with rocks highly contaminated by
chrysotile veins. On the contrary, working activities conducted on foliated serpentinites were related with airborne chrysotile
concentrations comparable with ambient levels. Environmental chrysotile concentrations were always below 2 ff/l, except for one
sample collected on a dirt road.
Conclusions: the present study would be useful for encouraging the development of an effective and harmonized policy for
proper use of contaminated rocks and protection of public health. This work was supported by Regione Lombardia
Occupational exposure and ambient air contamination by naturally occurring asbestos in Valmalenco (Italy)
No full textVariations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
[Newspaper Clipping: Author Claims Evidence of Second JFK Assassin #1]
No full textNewspaper article titled "Author Claims Evidence of Second JFK Assassin." The article states that author Richard J. Whalen concluded "that there is circumstantial evidence to support the theory of a second assassin in the shooting of President John F. Kennedy.
Also By The Same Author: AKTiveAuthor, a Citation Graph Approach to Name Disambiguation
No full textThe desire for definitive data and the semantic web drive for inference over heterogeneous data sources requires co-reference resolution to be performed on those data. In particular, name disambiguation is required to allow accurate publication lists, citation counts and impact measures to be determined. This paper describes a graph-based approach to author disambiguation on large-scale citation networks. Using self-citation, co-authorship and document source analyses, AKTiveAuthor clusters papers, achieving precision of 0.997 and recall of 0.818 over a test group of eight surname clusters
John F. Kennedy telegram to Roosevelt
No full textJersey Homesteads (later the Borough of Roosevelt) was established in the 1930s as an agro-industrial cooperative community. It was established specifically for urban Jewish garment workers, many of whom had emigrated from Europe. President John F. Kennedy sent a telegram to the citizens of Roosevelt, New Jersey, apologizing for not being able to attend the memorial dedication in honor of former President Franklin Delano Roosevelt. (Jersey Homesteads became Roosevelt in 1945 in honor of the president.) President Kennedy expressed his gratitude to the people of Roosevelt for constructing the memorial, and commented that it will serve as a constant reminder of Roosevelt's good works
Misure di prevenzione e protezione per ridurre l'esposizione a polveri contenenti silice libera cristallina. Comparto lapideo. Relazione conclusiva
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