A multipurpose X-ray fluorescence scanner developed for in situ analysis

Abstract: Over the time, instrument transportability has become more and more important, especially in Cultural Heritage, as often artworks cannot be moved from their site, either because of the size or due to problems with permission issues, or simply because moving them to a laboratory is physically impossible, as e.g. in the case of mural paintings. For this reason, the INFN-CHNet, the network for Cultural Heritage studies of the Italian National Institute of Nuclear Physics (INFN), has developed an XRF scanner for in situ analyses. The instrument is the result of a wide collaboration, where different units of the network have been developing the diverse parts, then merged in a single system. The XRF scanner has been designed to be a four-season and green instrument. The control/acquisition/analysis software has been fully developed by our group, using only open-source software. Other strong points of the system are easiness of use, high portability, good performances and ultra-low radiation dispersion, which allows us to use even when the public can be present. It can run both with mains or on batteries, in the latter case with a maximum runtime longer than 10 h. It has a very low cost, when compared to commercial systems with equivalent performances, and easily replaceable components, which makes it accessible for a much wider portion of the interested community. The system has been thought and designed as an open system, suitable for further development/improvements, that can result interesting for non-conventional XRF analysis. The CHNet XRF scanner has proved to be really very well suited for applications in the Cultural Heritage field, as testified by the many recent applications. This paper describes the present version of our instrument and reports on the tests performed to characterise its main features.Fil: Taccetti, F.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Castelli, L.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Czelusniak, C.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Gelli, N.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Mazzinghi, A.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Palla, L.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Ruberto, C.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Censori, C.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Lo Giudice, A.. Università di Torino; Italia. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Re, A.. Università di Torino; Italia. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Zafiropulos, D.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Arneodo, F.. New York University Abu Dhab; Emiratos Arabes UnidosFil: Conicella, V.. New York University Abu Dhab; Emiratos Arabes UnidosFil: Di Giovanni, A.. New York University Abu Dhab; Emiratos Arabes UnidosFil: Torres, R.. New York University Abu Dhab; Emiratos Arabes UnidosFil: Castella, F.. Universidad Nacional de San Martín. Instituto de Investigaciones sobre el Patrimonio Cultural; ArgentinaFil: Mastrangelo, Noemi Elisa. Universidad Nacional de San Martín. Instituto de Investigaciones sobre el Patrimonio Cultural; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gallegos, D.. Universidad Nacional de San Martín. Instituto de Investigaciones sobre el Patrimonio Cultural; ArgentinaFil: Tascon, Marcos. Universidad Nacional de San Martín. Instituto de Investigaciones sobre el Patrimonio Cultural; Argentina. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Marte, F.. Universidad Nacional de San Martín. Instituto de Investigaciones sobre el Patrimonio Cultural; ArgentinaFil: Giuntini, L.. Università degli Studi di Firenze; Itali

JPL Quarterly Technical Review, Volume 2, No. 1, April 1972

Mariner spacecraft equipment, propulsion systems, telemetry, and spacecraft trackin

Distribution automation applications of fiber optics

Motivations for interest and research in distribution automation are discussed. The communication requirements of distribution automation are examined and shown to exceed the capabilities of power line carrier, radio, and telephone systems. A fiber optic based communication system is described that is co-located with the distribution system and that could satisfy the data rate and reliability requirements. A cost comparison shows that it could be constructed at a cost that is similar to that of a power line carrier system. The requirements for fiber optic sensors for distribution automation are discussed. The design of a data link suitable for optically-powered electronic sensing is presented. Empirical results are given. A modeling technique that was used to understand the reflections of guided light from a variety of surfaces is described. An optical position-indicator design is discussed. Systems aspects of distribution automation are discussed, in particular, the lack of interface, communications, and data standards. The economics of distribution automation are examined

Report on active and planned spacecraft and experiments

Information is presented, concerning active and planned spacecraft and experiments known to the National Space Science Data Center. The information included a wide range of disciplines: astronomy, earth sciences, meteorology, planetary sciences, aeronomy, particles and fields, solar physics, life sciences, and material sciences. These spacecraft projects represented the efforts and funding of individual countries as well as cooperative arrangements among different countries

Optical tweezers combined with interference reflection microscopy for quantitative trapping and 3D imaging

Optical tweezers are an indispensable tool in biophysical single-molecule studies. They provide the ability to mechanically probe the characteristics of biological processes, such as active transport of cargo by molecular motors. To this end, functionalized (sub)micron- sized dielectric particles are held in a tightly focused laser trap while external forces lead to displacements of the particle from the trap center. The measurement and calibration of these displacements yield insights into the mechanical properties of the molecule of interest. The study of molecular motors, such as kinesins, is carried out in in vitro surface-based experimental assays. The experimental needs for such assays are challenging. The instrument must be stabilized, i.e. decoupled form external noise, and drift must be minimized, and it needs to be combined with state of the art microscopy techniques to visualize the sample. These are, on the one hand, single-molecule fluorescence detection and, on the other hand, robust label-free imaging of diffraction limited specimen. The latter is commonly realized by differential interference contrast (DIC) microscopy, which is an expensive and rather complicated technique that also restricts the design of the optical tweezers and, therefore, reduces the experimental possibilities. Optical tweezers experiments, moreover, rely on precise and reliable calibration. Despite its importance, calibration is, at times, carried out with obsolete methods or based on vague assumptions. Especially, in the vicinity of the sample surface, where hydrodynamic effects can have a significant influence, such assumptions fail largely. Here, height-dependent active power spectral density analysis of the Brownian motion of the trapped particle can ame- liorate these inaccuracies, but—compared to other methods—is rather cumbersome, time- consuming and easy-to-use solutions are lacking. In this work I designed and assembled an optical tweezers setup combined with total in- ternal reflection fluorescence (TIRF) microscopy. Furthermore, I succeeded to reduce design restrictions of the optical tweezers by combining it with interference reflection microscopy, which is a simple, cost-efficient and robust contrast technique that can visualize diffraction limited specimen in three dimensions, such as microtubules. Moreover, I was able to use this technique to determine the three-dimensional profile of an upward bent microtubule which I used to simultaneously calibrate the evanescent field depth of the TIRF microscope. In ad- dition, I programmed a free and open-source optical tweezers calibration software, PyOTC, that provides the means for height-dependent active power spectral density analysis. My work will possibly influence the design of optical tweezers instruments for surface-based experiments. LED-based IRM could further improve or complement label-free detection tech- niques such as interferometric scattering microscopy. The free and open-source calibration software package could help to precisely calibrate optical tweezers data. Moreover, because the source is available to anybody, calibration and therefore the analysis of optical tweezers data will be more transparent to the scientific community

Aerospace Medicine and Biology: A continuing bibliography (supplement 160)

This bibliography lists 166 reports, articles, and other documents introduced into the NASA scientific and technical information system in October 1976