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Maria Luísa Reis, João Batista Falcão, Giuliano Paulino, Cláudio Truyts
AERODYNAMIC LOADS MEASUREMENT OF A SOUNDING ROCKET VEHICLE TESTED IN WIND TUNNEL

In wind tunnels, aerospace vehicle models are tested in order to analyze their performance in real flight situations. The forces and moments exerted by the airflow on the surface of the test article are measured using multi-component balances. The balance measures the aerodynamic loads by using strain-gages. It is calibrated prior to the tests, resulting in the estimation of the parameters of the polynomial mathematical modelling relating the strain-gage readings to the aerodynamic loads. This paper presents the aerodynamic load values acting on a sounding rocket vehicle under test in a transonic aerodynamic facility. The force and moment coefficients and corresponding uncertainties are also estimated. The vehicle was tested in low Mach number conditions, with the airflow being supplied by the injection system. The second stage of the model was fitted with three different fin deflections. The measured quantities are total pressure, static pressure and total temperature of the flow, as well as the strain gage readings supplied by an internal balance. An analysis of the contribution for the uncertainties in the aerodynamic loads revealed that the measurement precision is the dominant component. The intermediate measurement precision of the tests was also considered.

J. Volf, P. Novak, K. Vitek, M. Novak, J. Vlcek, J. Stastny, R. Nedela
MULTI-AXES FORCE TRANSDUCER USING THE SYSTEM FOR ACTING PRESSURE IMAGE VISUALISATION

The special compact transducer has been developed – to be better known the force's and pressure's effects by transporting the loose materials. The projects of these transporting devices often demand to know not only the normal force's effect, but the effect of the lateral forces "the shearing or slip forces", too. The transducer creates two parts. First one is calibrated as Vector signal analyser – to be caught the elementary forces Fx, Fy, Fz (Cartesian system). The strain gauges are used on the special deformation "S–shape" element. Worth seeing - the second part of transducer - what is the small visualisation system. As the sensor - the conductive elastomer is used in matrix arrangement with the 286 sensing elements, to be caught the acting media pressure distribution. The signals digitising allows the onboard Image Preparation. The developed SW enables the PC–visualisation in real time; or the Digital Image Acquisition. By synchronising both parts, the other advances can be realised as: to record the elementary forces waveforms by dynamic mode, to analyse the pressure distribution up to 30 Hz (snaps/s), histogram 3D, auto-calibration, image correction etc.

Florbela A. Dias, Tânia Farinha, Fátima Dias, Eduarda Filipe
CALIBRATION AND VERIFICATION OF BREATH ALCOHOL DETECTORS IN PORTUGAL

In recent decades the ethanol metrology has became of significant importance, particularly in the area of individual's blood alcohol control.
Portuguese Institute for Quality is responsible for the calibration and metrological control of breath analyzers. This is done by means of comparison with mixtures of certified reference materials, which are traceable to IPQ and NMi primary standards.
This work aims to demonstrate the importance that the operations of calibration and metrological control of breath analyzers has in our society today, and also to present the calibration and verification procedure, errors calculations and the estimation of expanded uncertainties.

F. Corrêa Alegria
USING SINUSOIDAL INSTEAD OF TRIANGULAR STIMULUS SIGNALS IN THE IEEE1057 STANDARD RANDOM NOISE TEST OF ADCS

The random noise test of analogue to digital converters (ADCs) recommended by the IEEE 1057 Standard for Digitizing Waveform Recorders recommends the use of a triangular signal to stimulate the ADC under test. Here it will be shown that a sinusoidal stimulus signal can be used instead. This gives greater flexibility when carrying out the test and allows sine fitting algorithms to be employed to determine the initial phase of the two data records that need to be acquired. The knowledge of this initial phase can be used to align the two records and reduce the errors introduced by additive noise in the instant of acquisition trigger.

F. Corrêa Alegria
ERROR IN THE IEEE 1057 STANDARD RANDOM NOISE TEST OF ADCS

The random noise test of analogue to digital converters recommended by the IEEE 1057-2007 Standard for Digitizing Waveform Recorders is studied highlighting the estimation error and the influence of stimulus signal offset and amplitude on the estimation.

F. Corrêa Alegria
COMPARISON OF THE PRECISION OF GAIN AND OFFSET ESTIMATIONS OBTAINED WITH THE HISTOGRAM TEST OF ADCS

The Histogram Method of analogue to digital converter testing can be used to estimate their gain and offset error. There are two commonly used definitions for these parameters, namely "Terminal Based" and "Independently Based". In this paper the precision of those two different estimators is compared with the goal of assessing which one is more precise for the same number of samples and the same amount of additive noise.

F. Corrêa Alegria
BIAS IN ADC TERMINAL BASED GAIN AND OFFSET ESTIMATION USING THE HISTOGRAM METHOD

It is demonstrated that, when using the Histogram Test Method to test an analogue to digital converter, the presence of additive noise in the test setup or in the converter itself causes a bias in the terminal based estimation of the gain but not in the estimation of the offset. This will be demonstrated here by analytically determining the estimation error as a function of the sinusoidal stimulus signal amplitude and the noise standard deviation. A closed form approximate expression will be proposed for the computation of the bias of terminal based gain. The results presented are numerically validated using a Monte Carlo procedure.

Bruno Andò, Salvatore Baglio, S. La Malfa, Nicola Pitrone
A REMOTE MONITORING SYSTEM TO IMPROVE EDUCATIONAL ACTIVITIES OF VISUALLY IMPAIRED STUDENTS

A tool that could improve the quality of the assistance perceived by the visually impaired students, during a PC laboratory teaching session, is presented in this paper. The work of qualified supporting teachers could be highly improved by the use of suitable software and hardware facilities allowing for remote monitoring of students' physical and working condition. This could highly reduce the need for a continuous presence of a tutor, that might downgrade students' self estimate.

Dan Mihai Stefanescu, Valentin Butoescu
EQUIPMENT FOR DETERMINING AERODYNAMIC FORCES ON FLAPPING WINGS

Present work is devoted to the experimental determination of the non-steady aerodynamic forces acting on the flapping wings of the micro air vehicles (MAVs). At the National Institute for Aerospace Research from Bucharest, Romania, a multidisciplinary collective of scientists performed both theoretical and experimental research on flapping flight. In this work we present some aspects concerning the force measurement procedure in the range of small forces. The moment components given by the forces acting in two directions (perpendicular and parallel to the wing plane) are tensometrically measured while the flapping and pitching angles are determined using two precision potentiometers. All signals are transmitted to computer via a multifunction DAQ National Instruments PCI-6221, Windows compatible. LabVIEW SignalExpress LE together with NI-DAQmx can gather, register, export and visualize experimental data. The analysis includes the extraction of the inertial forces which are the predominant ones, making possible the accurate determination of the aerodynamic forces on the flapping wings.

Pasquale Arpaia, Vitaliano Inglese, Giuseppe La Commara
SOFTWARE QUALITY CHARACTERIZATION OF THE FLEXIBLE FRAMEWORK FOR MAGNETIC MEASUREMENTS AT CERN

The paper deals with the measurement of software quality in frameworks for automatic test systems. In particular, the quality characterization of software components inside the Flexible Framework for Magnetic Measurements, developed at the European Organization for Nuclear Research (CERN), is illustrated with respect to the ISO 9126 reference model through the introduction of suitable metrics. Experimental results for code quality assessment are finally reported.

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