Civil engineering is a branch of science that covers a broad range of areas where experimental procedures often plays an important role. The research in this field is usually supported by experimental structures able to test physical and mathematical models and to provide measurement results with acceptable accuracy. To assure measurement quality, a metrology probabilistic approach can provide valuable mathematical and computational tools especially suited to the study, evaluation and improvement of measurement processes in its different components (modeling, instrumentation performance, data processing, data validation and traceability), emphasizing measurement uncertainty evaluation as a tool to the analysis of results and to promote the quality and capacity associated with decision-making. This paper presents some of the research held by the metrology division of the Portuguese civil engineering research institutes, focused on the contribution of measurement uncertainty studies to a variety of frameworks, such as testing for metrological characterization and physical and mathematical modeling. Experimental data will be used to illustrate practical cases.

The solid flow in air-catalyst in circulating fluidized bed was simulated with CFD model to obtain axial and radial distribution. Therefore, project parameters were confirmed and steady state operation condition was improved. Solid holds up axial end radial profiles simulation and comparison with gamma transmission measurements are in a good agreement. The transmission signal from an 241Am radioactive source was evaluated in NaI(Tl) detector coupled to multichannel analyzer. This non intrusive measuring set up is installed at riser of a cold pilot unit to determine parameters of FCC catalyst flow at several concentrations. Mass flow rate calculated by combining solid hold up and solid phase velocity measurements was compared with catalyst inlet measured at down-comer. Evaluation in each measured parameter shows that a relative combined uncertainty of 6% in a 95% interval was estimated. Uncertainty analysis took into account a significant correlation in scan riser transmission measurements. An Eulerian approach of CFD model incorporating the kinetic theory of granular flow was adopted to describe the gas–solid two-phase flows in a multizone circulating reactor. Instantaneous and local gas-particle velocity, void fraction and turbulent parameters were obtained and results are shown in 2 D and 3D graphics.

This paper presents the evaluation of the uncertainty for the length measurement of gauge blocks by optical interferometry. In order to improve the gauge block calibration method and to decrease measurement uncertainty the old Zeiss-Kösters gauge block interferometer has been modified and improved by DMDM (Directorate of Measures and Precious Metals of Serbia). The main modification of the interferometer covers introduction of two laser sources, as new wavelength standards, as well as new hardware system and interferometer software, developed to completely automate the calibration process. The validation of the new measurement procedure details the uncertainty budget. The measurement method and model equation, which serves as the basis for the uncertainty evaluation is described. The uncertainty evaluation is performed in accordance with the document JCGM 100:2008-Evaluation of measurement data – Guide to the expression of uncertainty in measurement (GUM).

In this work we present an experimental investigation of the employment usage application of the vertical pixel binning (PB) option for PIV (particle image velocimetry) measurements. The PB option increases the speed of a CCD, at the cost of loosing spatial resolution. Consequently, it is expected that PB will positively impact the dynamic velocity range of the PIV measurements. In order to show the benefit of the CCD PB option in PIV measurements, we have carried out series of microPIV experiments on laminar flows, seeded with 1 μm fluorescent polystyrene microparticles and passing through a 200 μm × 200 μm × 50000μm microchannel. The flow images were recorded at normal, 2 × 1, and 3 × 1 vertical PB modes of a monochrome CCD camera. The experimentally obtained velocity profiles were calculated using the ensemble-averaged cross-correlation method and Gaussian sup-pixel interpolation and then compared with theoretically calculated velocity profiles. We found that the error introduced by the PB option did not exceed the inherent uncertainty of the PIV system used. For a particular PIV system CCD camera, using the PB option allowed an increase in the dynamic velocity range of a PIV system by more than a factor of two, without extra investments.

The Statistical Feed-Forward Control Model (SFFCM) relies on a sequence of specification adjustments made on subsets of a population to counter the influence of the long time component of the variation. The difficulty strives in finding a proper estimate for the measure of the central tendency of each subset to minimize the number of the required adjustments. By means of simulating the assembly of two components having high dimensional variation, forty experiments were designed to compare the individual influence of different factors such as the number of adjustments, the sampling strategy and two measures of central tendency: the sample mean and the cumulative de-noised average. Simulation results showed that, regardless of the sampling strategy but keeping the inspection rate at 20%, the use of the cumulative de-noised average instead of the sample mean made possible to reduce the number of adjustments by 20%. Thus, while the shift mean of the resulting assembly was decreased by 90%; the standard deviation was reduced by 15%. Hence, the selection of a proper central tendency measure is crucial when modeling the long time variation. The cumulative de-noised average proved to be a valid alternative.

Mean residual life and failure rate functions are ubiquitously employed in reliabilityanalysis. The term of useful period of lifetime distributions of bathtub-shaped failurerate functions is referred to the flat rigion of this function and has attracted authorsand researchers in reliability, actuary, and survival analysis. In recent years,considering the change points of mean residual life and failure rate functions has beenextensively utelized in determining the optimum burn-in time. In this paper we investigatethe difference between the change points of failure rate and mean residual life functionsof some generalized gamma type distributions due to the capability of these distributionsin modeling various bathtub-shaped failure rate functions.

We describe an efficient continuous-wave diode-pumped Nd:YLiF4 laseroscillating on the σ-polarized4F3/2-4I13/2transition at λω = 1312 nm. With a simplelinear cavity laser, we reached an intracavity power of 310 W at λ = 1312nm for 16 W of absorbed pump power(λp ~ 806 nm). A 0.25 W of tunableradiation (λ2ω = 656−658 nm) was obtainedby intracavity second-harmonic generation (SHG) with a 5 × 5 × 7mm3β-BaB2O4 crystal. Up to 10 mW oftunable single-frequency operation was observed using a 200 μm thin fusedsilica intracavity solid etalon. The optimal waist for a maximum conversion efficiency hasbeen calculated theoretically using Boyd and Kleiman model. For the 1312–656 nm SHG, wefound a walk-off parameter B = 8.99 and an optimal waist of 25μm. Comparing to the experimental measurement of the optimal waist, wefound a relative discrepancy of 2.84 × 10-2. This laser is dedicated to thespectroscopic study of silver atoms trapped in a buffer-gas-free paraffin coated Pyrexcell that will be used in a compact atomic optical clock.