Experimental approach for the uncertainty assessment of 3D complex geometry dimensional measurements using computed tomography at the mm and sub-mm scales

The dimensional verification of miniaturized components with 3D complex geometries is particularly challenging. Computed Tomography (CT) can represent a suitable alternative solution to micro metrology tools based on optical and tactile techniques. However, the establishment of CT systems’ traceability when measuring 3D complex geometries is still an open issue. In this work, an alternative method for the measurement uncertainty assessment of 3D complex geometries by using CT is presented. The method is based on the micro-CT system Maximum Permissible Error (MPE) estimation, determined experimentally by using several calibrated reference artefacts. The main advantage of the presented method is that a previous calibration of the component by a more accurate Coordinate Measuring System (CMS) is not needed. In fact, such CMS would still hold all the typical limitations of optical and tactile techniques, particularly when measuring miniaturized components with complex 3D geometries and their inability to measure inner parts. To validate the presented method, the most accepted standard currently available for CT sensors, the Verein Deutscher Ingenieure/Verband Deutscher Elektrotechniker (VDI/VDE) guideline 2630-2.1 is applied. Considering the high number of influence factors in CT and their impact on the measuring result, two different techniques for surface extraction are also considered to obtain a realistic determination of the influence of data processing on uncertainty. The uncertainty assessment of a workpiece used for micro mechanical material testing is firstly used to confirm the method, due to its feasible calibration by an optical CMS. Secondly, the measurement of a miniaturized dental file with 3D complex geometry is carried out. The estimated uncertainties are eventually compared with the component’s calibration and the micro manufacturing tolerances to demonstrate the suitability of the presented CT calibration procedure. The 2U/T ratios resulting from the validation workpiece are, respectively, 0.27 (VDI) and 0.35 (MPE), by assuring tolerances in the range of +- 20–30 micro-m. For the dental file, the EN < 1 value analysis is favorable in the majority of the cases (70.4%) and 2U/T is equal to 0.31 for sub-mm measurands (L < 1 mm and tolerance intervals of +- 40–80 micro-m)

Beam test results of the irradiated Silicon Drift Detector for ALICE

The Silicon Drift Detectors will equip two of the six cylindrical layers of high precision position sensitive detectors in the ITS of the ALICE experiment at LHC. In this paper we report the beam test results of a SDD irradiated with 1 GeV electrons. The aim of this test was to verify the radiation tolerance of the device under an electron fluence equivalent to twice particle fluence expected during 10 years of ALICE operation.Comment: 6 pages,6 figures, to appear in the proceedings of International Workshop In high Multiplicity Environments (TIME'05), 3-7 October 2005, Zurich,Switzerlan

Métodos para determinar taninos em sorgo, avaliando-se o desempenho de aves e a digestibilidade in vitro da matéria seca.

Com o objetivo de comparar metodos para determinar a presenca de taninos em sorgo (Sorghum bicolor (L.) Moench), foi conduzido um experimento com aves e realizada a analise da digestibilidade "in vitro" da materia seca. Foram avaliados os metodos Azul da Prussia, Vanilina/HCI e Proantocianidina, e na preparacao das racoes, foram utilizados dez diferentes hibridos de sorgo e uma variedade de milho. A presenca de compostos fenolicos determinada pelo metodo Azul da Prussia apresentou maior correlacao com o ganho de peso das aves e a digestibilidade "in vitro" da materia seca

Characterisation of demoulding parameters in micro-injection moulding

YesCondition monitoring of micro injection moulding is an effective way of understanding the processing effects of variable parameter settings. This paper reports an experimental study that investigates the characteristics of the demoulding behaviour in micro injection moulding (A mu-IM) with a focus on the process factors that affect parts' quality. Using a Cyclic Olefin Copolyme (COC) microfluidics demonstrator, the demoulding performance was studied as a function of four process parameters (melt temperature, mould temperature, holding pressure and injection speed), employing the design of experiment approach. The results provide empirical evidences on the effect that processing parameters have on demoulding conditions in A mu-IM, and identifies combinations of parameters that can be used to achieve the optimal processing conditions in regards to demoulding behaviour of micro parts. It was concluded that there was a direct correlation between the applied pressure during part filling, holding phases and the demoulding characteristic factors of the A mu-IM cycle such as ejection force, integral and time

Influence of the source of pollen on the oil content of maize grains

Os efeitos da fonte polinizadora sobre a percentagem de óleo em milho (Zea mays L.) foram avaliados em grãos provenientes de espigas autofecundadas e de polinização livre. Ambos os tipos de espigas foram obtidos de uma mesma planta, a fim de evitar os efeitos do citoplasma e do genoma materno. Foi usado o germoplasma de milho ESALQ VF 1, de grãos do tipo duro e de cor de laranja. Os resultados obtidos pela análise direta do conteúdo de óleo dos grãos revelaram uma depressão endogâmica de 4%, indicando a participação direta da fonte polinizadora no germoplasma estudado. Em programas de melhoramento, visando o aumento do conteúdo de óleo nos grãos de milho, neste germoplasma, as progênies poderão ser selecionadas, tanto através de sementes autofecundadas, como de polinização livre, pois a correlação linear entre os dois tipos de sementes foi elevada e positiva (r = 0,67**). Contudo, o uso de sementes de polinização livre proporciona menores custos operacionais ao programa. Além de possibilitar o ganho de uma geração, exibe considerável variabilidade genética entre sementes da mesma espiga.The present study evaluated the effects of source of pollen on the oll content of maize grains (Zea mays L.). Seed was used from two ears from the same plant, one that was self-fertilized and the other one open-pollinated. The work was conducted with germplasm ESALQ VF 1, an orange-coloured, hard grain type. The results of the analysis of oil content showed that there was an inbreeding depression of 4%, indicating the effective participation of source of pollen in the germplasm studied. In improvement programs to increase the oil content in maize grains, in this germplasm, progenies can be selected either through self-fertilized seeds or by open-pollination since the linear correlation between the two types of seeds was high and positive (r = 0.67**). The use of open-pollinated seed would mean lower operating costs in the program. Since this characteristic is being determined by the genotype of its own seed, it represents available genetic variation between seed of the same ear

Correlación entre contenido de aceite, rendimiento y otros caracteres agronómicos en maíz (Zea mays L.).

Este trabajo fue realizado para conocer las correlaciones genéticas y fenotípicas entre porcentaje de aceite, rendimientos de granos y otros caracteres agronómicos de la planta de maíz. Se utilizaron 2 poblaciones de alto contenido de aceite y contrastantes en el tipo de grano (Flint versus dentado): Piranao VD-2-MI-AO Y Piranao VF-1-MI-AO. Ambas poblaciones pertenecen al tercer ciclo de selección recurrente para alto contenido de aceite en el grano, y se derivan de las poblaciones Piranao VD-2-MI-O Y Piranao VF-1-MI-O. Los coeficientes de correlación genética entre el porcentaje de aceite y los caracteres altura de planta y altura de mazorca, mostraron tendencia negativa, excepto en la altura de la planta para Piranao VF-1-MI-AO. Los valores de las correlaciones genéticas entre porcentaje de aceite, rendimiento de granos y otros caracteres de la mazorca, resultaron divergentes, en su mayoría, para las 2 poblaciones. En Piranao VD-2-MI-AO, las asociaciones fueron positivas, evidenciando que el contenido de aceite puede ser incrementado sin causar detrimentos en el rendimiento de granos por la baja magnitud del coeficiente correlación genética. Contrariamente, el mejoramiento en contenido de aceite para Piranao VF-1-MI-AO puede causar decrecimiento en el rendimiento de granos y otros atributos de la mazorca, debido a las posibles limitaciones bioenergéticas para aumentar el contenido de aceite, que afectan la síntesis de carbohidratos en la semillaMaíz-Zea may

Test results of the front-end system for the Silicon Drift Detectors of ALICE

The front-end system of the Silicon Drift Detectors (SDDs) of the ALICE experiment is made of two ASICs. The first chip performs the preamplification, temporary analogue storage and analogue-to-digital conversion of the detector signals. The second chip is a digital buffer that allows for a significant reduction of the connection from the front-end module to the outside world. In this paper, the results achieved on the first complete prototype of the front-end system for the SDDs of ALICE are presented