Calibration uncertainty estimation for internal aerodynamic balance

Aerodynamic balances are employed in wind tunnels to estimate the forces and moments acting on the model under test. This paper proposes a methodology for the assessment of uncertainty in the calibration of an internal multi-component aerodynamic balance. In order to obtain a suitable model to provide aerodynamic loads from the balance sensor responses, a calibration is performed prior to the tests by applying known weights to the balance. A multivariate polynomial fitting by the least squares method is used to interpolate the calibration data points. The uncertainties of both the applied loads and the readings of the sensors are considered in the regression. The data reduction includes the estimation of the calibration coefficients, the predicted values of the load components and their corresponding uncertainties, as well as the goodness of fit.

A simple interferometric method to measure the calibration factor and displacement amplification in piezoelectric flextensional actuators

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Power flow for primary distribution networks considering uncertainty in demand and user connection

This paper presents a method for calculating the power flow in distribution networks considering uncertainties in the distribution system. Active and reactive power are used as uncertain variables and probabilistically modeled through probability distribution functions. Uncertainty about the connection of the users with the different feeders is also considered. A Monte Carlo simulation is used to generate the possible load scenarios of the users. The results of the power flow considering uncertainty are the mean values and standard deviations of the variables of interest (voltages in all nodes, active and reactive power flows, etc.), giving the user valuable information about how the network will behave under uncertainty rather than the traditional fixed values at one point in time. The method is tested using real data from a primary feeder system, and results are presented considering uncertainty in demand and also in the connection. To demonstrate the usefulness of the approach, the results are then used in a probabilistic risk analysis to identify potential problems of undervoltage in distribution systems. (C) 2012 Elsevier Ltd. All rights reserved.

Modeling a spatially restricted distribution in the Neotropics: How the size of calibration area affects the performance of five presence-only methods

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Precise Measurement of the Top-Quark Mass from lepton plus jets Events

We measure the mass of the top quark using top-quark pair candidate events in the lepton+jets channel from data corresponding to 1 fb(-1) of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron collider. We use a likelihood technique that reduces the jet energy scale uncertainty by combining an in situ jet energy calibration with the independent constraint on the jet energy scale (JES) from the calibration derived using photon+jets and dijet samples. We find the mass of the top quark to be 171.5 +/- 1.8(stat.+JES)+/- 1.1(syst.) GeV.

Measurement of the inclusive jet cross section in p(p)over-bar collisions at root s=1.96 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Determination of jet energy calibration and transverse momentum resolution in CMS

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Mapping an uncertainty zone between interpolated types of a categorical variable

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

DERIVATION OF THE ENERGY-TIME UNCERTAINTY RELATION

A derivation from first principles is given of the energy-time uncertainty relation in quantum mechanics. A canonical transformation is made in classical mechanics to a new canonical momentum, which is energy E, and a new canonical coordinate T, which is called tempus, conjugate to the energy. Tempus T, the canonical coordinate conjugate to the energy, is conceptually different from the time t in which the system evolves. The Poisson bracket is a canonical invariant, so that energy and tempus satisfy the same Poisson bracket as do p and q. When the system is quantized, we find the energy-time uncertainty relation DELTAEDELTAT greater-than-or-equal-to HBAR/2. For a conservative system the average of the tempus operator T is the time t plus a constant. For a free particle and a particle acted on by a constant force, the tempus operators are constructed explicitly, and the energy-time uncertainty relation is explicitly verified.

Construction and calibration of permeation tubes.

A dynamic system for stablishing a known standard gas mixture is necessary for many studies such as development and testing of analytical methods. A permeation tube can be used for this purpose. The work described here shows the construction, operation and calibration of a simple permeation tube which can be used to obtain large amounts of a standard gas.

Transmission network expansion planning considering uncertainty in demand

This paper presents two mathematical models and one methodology to solve a transmission network expansion planning problem considering uncertainty in demand. The first model analyzed the uncertainty in the system as a whole; then, this model considers the uncertainty in the total demand of the power system. The second one analyzed the uncertainty in each load bus individually. The methodology used to solve the problem, finds the optimal transmission network expansion plan that allows the power system to operate adequately in an environment with uncertainty. The models presented are solved using a specialized genetic algorithm. The results obtained for several known systems from literature show that cheaper plans can be found satisfying the uncertainty in demand.

Comparison of proton energy loss in thick absorbers in terms of a reduced calibration curve

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Calibration of therapeutic ultrasound equipment

Temporal and spatial acoustic intensity (SATA) of therapeutic ultrasound (US) equipment should be monitored periodically. In order to evaluate the conditions of US equipment in use in the city of Piracicaba-Sao Paulo, Brazil, 31 machines - representing all Brazilian manufacturers - were analysed under continuous and pulsed conditions at a frequency of 1 MHz. Data about temporal and spatial acoustic intensity were collected and the use of equipment was surveyed. Intensities of 0.1, 0.2, 0.5, 0.8, 1.0, 1.5, 2.0, 2.5 and 3.0 Wcm -2, indicated on the equipment panel were analysed using a previously calibrated digital radiation pressure scale, model UPM-DT-1 (Ohmic Instruments Co). The acoustic intensity (I) results were expressed as superior and inferior quartile ranges for transducers with metal surfaces of 9 cm 2 and an effective radiation area (ERA) Of 4 cm 2. The results under continuous conditions were: I 0.1 = -20.0% and -96%. I 0.2 = -3.1% and -83.7%. I 0.5 = -35.0% and -86.5%. I 0.8 = -37.5% and -71.0%. I 2.5 = -49.0% and -69.5%. I 3.0 = -58.1% and -77.6%. For pulsed conditions, intensities were: I 0.1 = -40.0% and -86.2%. I 1.0 = -50.0% and -86.5%. I 1.5 = -62.5% and -82.5%. I 2.0 = -62.5% and -81.6%. I 2.5 = -64.7% and -88.8%. I 3.0 = -87.1% and -94.8%. In reply to the questionnaire drawn up to check the conditions of use of equipment, all users reported the use of hydrosoluble gel as a coupling medium and none had carried out previous calibrations. Most users used intensities in the range of 0.4. to 1.0 Wcm -2 and used machines for 300 to 400 minutes per week. The majority of machines had been bought during the previous seven years and weekly use ranged from less than 100 minutes to 700 minutes (11 hours 40 minutes). Findings confirm previous observations of discrepancy between the intensity indicated on the equipment panel and that emitted by the transducer and highlight the necessity for periodic evaluations of US equipment.

Line based camera calibration in machine vision dynamic applications

The problem of dynamic camera calibration considering moving objects in close range environments using straight lines as references is addressed. A mathematical model for the correspondence of a straight line in the object and image spaces is discussed. This model is based on the equivalence between the vector normal to the interpretation plane in the image space and the vector normal to the rotated interpretation plane in the object space. In order to solve the dynamic camera calibration, Kalman Filtering is applied; an iterative process based on the recursive property of the Kalman Filter is defined, using the sequentially estimated camera orientation parameters to feedback the feature extraction process in the image. For the dynamic case, e.g. an image sequence of a moving object, a state prediction and a covariance matrix for the next instant is obtained using the available estimates and the system model. Filtered state estimates can be computed from these predicted estimates using the Kalman Filtering approach and based on the system model parameters with good quality, for each instant of an image sequence. The proposed approach was tested with simulated and real data. Experiments with real data were carried out in a controlled environment, considering a sequence of images of a moving cube in a linear trajectory over a flat surface.

Rapid determination of zinc in foods by flow injection analysis with flame AAS using gradient calibration method

A calibration method was developed using flow injection analysis (FI) with a Gradient Calibration Method (GCM). The method allows the rapid determination of zinc In foods (approximately 30 min) after treatment with concentrated sulphuric acid and 30% hydrogen peroxide, and analysis with flame atomic absorption spectrometry (FAAS). The method provides analytical results with a relative standard deviation of about 2% and requires less time than by conventional FI calibration. The electronic selection of different segments along the gradient and monitoring of the technique covers wide concentration ranges while maintaining the inherent high precision of flow injection analysis. Concentrations, flow rates, and flow times of the reagents were optimized in order to obtain best accuracy and precision. Flow rates of 10 mL/min were selected for zinc. In addition, the system enables electronic dilution and calibration where a multipoint curve can be constructed using a single sample injection.