1,720,982 research outputs found
Allestimento del laboratorio Cp107 per misure in corrente continua di alto valore di resistenza elettrica
No full textQuesto rapporto tecnico descrive gli interventi migliorativi operati sul nuovo allestimento sperimentale impiegato per le misure di alta resistenza eseguite nel laboratorio Cp 107. Gli interventi comprendono l’adeguamento degli impianti elettrici alla normativa sulla sicurezza elettrica e la riduzione del rumore elettromagnetico con i miglioramenti dei collegamenti di terra. Inoltre, sono stati effettuati il ripristino del sistema di condizionamento ambientale all'interno della camera schermata, il controllo dell’esperimento da remoto per contenere le operazioni in presenza di potenziali elettrici elevati, per mitigare i disturbi all'esperimento in corso.This technical report describes the improvement interventions made on the lay-out used for the high resistance measurements performed in the laboratory Cp 107. The interventions include the revision
of electrical systems to the electrical safety regulations and the reduction of electromagnetic noise with improvements ground connections. Also it was implemented an improvement of the environmental conditioning system inside the screened room, it was improved the remote control of the experiment to contain operations in the presence of high electrical potentials and it was mitigated the disturbances to the experiment in progress
A portable rotating disk prototype for LDA calibration
No full textINRIM has developed a LDA calibrator prototype for a speed range between 0.02 m/s and 10 m/s. The prototype has been designed to be rugged, compact and portable in order to be used as a possible transfer device for LDA calibration comparisons. The device is composed by a rotating disk with a surface manufactured that simulates the tracer particles and by an alignment system to adapt the calibrator to different focal lengths and beam angles. Detailed descriptions of this prototype and preliminary results are shown in this paper in order to validate the operating principles
R.T. 2/2014 ‐ Realizzazione di un taratore per LDA nel range di velocità da 0.05 m/s a 50 m/s: Progetto preliminare
No full textLaser Frequency Stabilization for Aerospace Applications
No full textLong term frequency stability of lasers is a key parameter in many research areas
ranging from dimensional metrology to fundamental physics. Many solutions have
been proposed by the scientific community and lasers whose frequency is referenced
to molecular transitions are commonly used when long term stability and wavelength
accuracy are needed. Our goal is the development of a frequency stabilization system
with a relative frequency stability (Allan variance) of 1E-12 over 1 second integration
time which will be suitable for aerospace applications. The frequency reference is a
10 cm long Fabry-Perot optical resonator which has been designed in order to
withstand the huge launch loads (up to 30g at 1 kHz). As the stability of the resonant
frequency is determined by the long term stability of the cavity length, a low CTE
material (ULE) was adopted as the cavity spacer. During the laboratory tests the
cavity has been housed inside a mechanical insulating vacuum chamber, thermally
controlled by a digital system. The laser is referenced to one of the cavity resonances
by means of a digital implementation of the Pound-Drever-Hall technique. An FPGA
equipped with a small number of auxiliary components provides a flexible and
reconfigurable digital system. A laser was locked to an iodine transition using the
“digital PDH” and a classical analog system; the same frequency stability (parts in
1E13 over a 1 second integration time) was measured. Currently we are working on the
implementation of the thermostat in order to properly length-stabilize the Fabry-Perot
resonator and to characterize the coefficient of thermal expansion of the ULE spacer
we are using
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Concentrazione delle cellule C nella tiroide di ratti trattati con mercaptoimidazolo o con levotiroxina
No full textConcentration of C cells in the thyroid of rats treated with Mercaptoimidazole or Levo-thyroxine. The aim of the present study was to elucidate the possible functional relationship between follicular and parafollicular cells of the thyroid gland; therefore we have investigated the behaviour of calcitonin producing cells and serum calcitonin concentration in rats both in resting and hyperstimulation conditions of follicular cells. Our results showed that with regard to follicular mass the concentration of the C cells was reduced in the two groups of rats treated compared to control rats. C cell concentration decrease was associated with reduced serum calcitonin concentration. In conclusion C cell activity is independent of TSH and thyroid hormones circulating levels
Cartesian approach to large scale co-ordinate measurement: InPlanT
No full textA novel paradigm of coordinate measurement is presented, named InPlanT. The target application is the industrial measurement of large workpieces in harsh conditions, e.g. in aerospace industry.
Like other techniques, a large measuring volume is covered by laser light with no contact. Unlike most other techniques, InPlanT relies on light only to point to a target, while the actual measurement is done by standard position sensors, such as linear encoders or interferometers. The actual coordinate measurement is relegated to the border of the measuring volume, possibly protected against a harsh environment.
The principle, and the characteristics and expected errors of the main InPlanT subsystems, are described. The preliminary experimental results of the most critical subsystem – responsible to detect the target – are promising
Variations on the Author
Full text link“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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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