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  • 1
    Language: English
    In: Optics and Lasers in Engineering, 2015, Vol.75, p.72(9)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.optlaseng.2015.06.009 Byline: Paolo Mazzoleni, Emanuele Zappa, Fabio Matta, Michael A. Sutton Abstract: The accuracy and spatial resolution of full-field deformation measurements performed through digital image correlation are greatly affected by the frequency content of the speckle pattern, which can be effectively controlled using particles with well-defined and consistent shape, size and spacing. This paper introduces a novel toner-transfer technique to impress a well-defined and repeatable speckle pattern on plane and curved surfaces of metallic and cement composite specimens. The speckle pattern is numerically designed, printed on paper using a standard laser printer, and transferred onto the measurement surface via a thermo-mechanical process. The tuning procedure to compensate for the difference between designed and toner-transferred actual speckle size is presented. Based on this evidence, the applicability of the technique is discussed with respect to surface material, dimensions and geometry. Proof of concept of the proposed toner-transfer technique is then demonstrated for the case of a quenched and partitioned welded steel plate subjected to uniaxial tensile loading, and for an aluminum plate exposed to temperatures up to 70% of the melting point of aluminum and past the melting point of typical printer toner powder. Author Affiliation: (a) Rolls-Royce, Pride Park, Derby DE24 8LY, UK (b) Department of Mechanical Engineering, Politecnico di Milano, via La Masa 1, 20156 Milan, Italy (c) Department of Civil and Environmental Engineering, University of South Carolina, 300 Main Street, Columbia, SC 29208, USA (d) Department of Mechanical Engineering, University of South Carolina, 300 Main Street, Columbia, SC 29208, USA Article History: Received 5 January 2015; Revised 18 May 2015; Accepted 29 June 2015
    Keywords: Laser Printers ; Cements (Building Materials) ; Aluminum Plate
    ISSN: 0143-8166
    Source: Cengage Learning, Inc.
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  • 2
    Language: English
    In: Gait & Posture, January 2011, Vol.33(1), pp.6-13
    Description: Standard clinical gait analysis protocols usually limit to test self-selected speed gait: this approach is generally valid and permits time and cost saving. Yet, the literature evidences suggest that some pathologies (especially at onset or subclinical level) may not primarily affect plain gait, but more demanding locomotor tasks. In the present study we therefore propose a multiple-task gait analysis protocol including: self-selected, increased and decreased speed gait; walking on toes; walking on heels; step ascending and step descending, and apply it to 40 healthy subjects (20 aged 6–17, 20 aged 22–72) thus building extensive reference data set. Published studies already report normative data for some of these tasks, but inhomogeneously (due to different collecting methods and biomechanical models, population characteristics, nature of data). We verify a good correlation between our results and those presented by Schwartz et al. (2008) in their study providing extensive data on the effect of walking speed on the gait of healthy children. In discussing the results, the rationale and effectiveness of each task is confirmed, and we supply an electronic addendum with comprehensive kinematic, kinetic and electromyographic normative data for the considered population, along with a set of reference parameters and related statistical analysis, as a premise for further applications on pathological subjects.
    Keywords: Gait Analysis ; Toe-Walking ; Heel-Walking ; Step Negotiation ; Clinical Decision Making ; Medicine ; Anatomy & Physiology
    ISSN: 0966-6362
    E-ISSN: 1879-2219
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  • 3
    Language: English
    In: Analytical and Bioanalytical Chemistry, 2011, Vol.399(9), pp.3147-3153
    Description: We report on a non-destructive study of Sicilian ceramic fragments of cultural heritage interest, classified as “proto-majolica” pottery and dating back to the twelfth to thirteen centuries AD. The analytical approach used is based on the employment of two totally non-invasive spectroscopic techniques: X-ray fluorescence (XRF), using a portable energy-dispersive XRF analyser, and X-ray absorption spectroscopy, using synchrotron radiation as a probe (SR-XAS). XRF measurements allowed us to collect elemental and spatially resolved information on major and minor constituents of the decorated coating of archaeological pottery fragments, so providing preliminary results on the main components characterizing the surface. In particular, we assigned to Fe and Mn the role of key elements of the colouring agent. With the aim of obtaining more detailed information, we performed SR-XAS measurements at the Fe and Mn K-edges at the Italian BM08 beamline at the European Synchrotron Radiation Facility (Grenoble, France). The experimental data were analysed by applying principal component analysis and least-squares fitting to the near-edge part of the spectra (X-ray absorption near-edge structure) to determine the samples’ speciation. From the overall results, umber, a class of brownish pigments characterized by a mixture of hydrated iron and manganese oxides, has been ascribed as a pigmenting agent. Figure Fe K-edge XANES spectra of selected proto-majolica samples and reference compounds (FeO, Fe3O4, Fe2O3, Fe+SiO2). D pigmented, L not pigmented.
    Keywords: X-ray fluorescence ; X-ray absorption spectroscopy ; Non-destructive methods ; Pigments
    ISSN: 1618-2642
    E-ISSN: 1618-2650
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  • 4
    Language: English
    In: Optics and Lasers in Engineering, March, 2015, Vol.66, p.19(15)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.optlaseng.2014.08.004 Byline: Paolo Mazzoleni, Fabio Matta, Emanuele Zappa, Michael A. Sutton, Alfredo Cigada Abstract: This paper discusses the effect of pre-processing image blurring on the uncertainty of two-dimensional digital image correlation (DIC) measurements for the specific case of numerically-designed speckle patterns having particles with well-defined and consistent shape, size and spacing. Such patterns are more suitable for large measurement surfaces on large-scale specimens than traditional spray-painted random patterns without well-defined particles. The methodology consists of numerical simulations where Gaussian digital filters with varying standard deviation are applied to a reference speckle pattern. To simplify the pattern application process for large areas and increase contrast to reduce measurement uncertainty, the speckle shape, mean size and on-center spacing were selected to be representative of numerically-designed patterns that can be applied on large surfaces through different techniques (e.g., spray-painting through stencils). Such "designer patterns" are characterized by well-defined regions of non-zero frequency content and non-zero peaks, and are fundamentally different from typical spray-painted patterns whose frequency content exhibits near-zero peaks. The effect of blurring filters is examined for constant, linear, quadratic and cubic displacement fields. Maximum strains between [+ or -]250 and [+ or -]20,000[micro][epsilon] are simulated, thus covering a relevant range for structural materials subjected to service and ultimate stresses. The robustness of the simulation procedure is verified experimentally using a physical speckle pattern subjected to constant displacements. The stability of the relation between standard deviation of the Gaussian filter and measurement uncertainty is assessed for linear displacement fields at varying image noise levels, subset size, and frequency content of the speckle pattern. It is shown that bias error as well as measurement uncertainty are minimized through Gaussian pre-filtering. This finding does not apply to typical spray-painted patterns without well-defined particles, for which image blurring is only beneficial in reducing bias errors. Author Affiliation: (a) Rolls-Royce plc, MV-GF, Victory Road, P.O. Box 31, Derby DE24 8BJ, UK (b) Dept. of Civil and Environmental Engineering, University of South Carolina, 300 Main Street, Columbia, SC 29208, USA (c) Dept. of Mechanical Engineering, Politecnico di Milano, via La Masa 1, 20156 Milan, Italy (d) Dept. of Mechanical Engineering, University of South Carolina, 300 Main Street, 29208 Columbia, SC, USA Article History: Received 18 April 2014; Revised 21 July 2014; Accepted 4 August 2014
    Keywords: Building Materials
    ISSN: 0143-8166
    Source: Cengage Learning, Inc.
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  • 5
    Language: English
    In: Optics and Lasers in Engineering, May, 2014, Vol.56, p.140(12)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.optlaseng.2013.12.016 Byline: Emanuele Zappa, Paolo Mazzoleni, Ali Matinmanesh Abstract: Even though digital image correlation (DIC) is a widely used optical full field measurement method, it still needs further performance investigations, when it comes to dynamic conditions. Dealing with a moving target, causes a motion effect (i.e. blurring) on the acquired images. This factor is an important source of uncertainty that needs to be quantified. Therefore, the present study aims to perform a systematic uncertainty assessment of DIC method in general dynamic applications. The study focuses on 2D DIC. In the case of 3D DIC similar problems will arise and therefore, a complete understanding of two dimensional conditions will be of great help to further studies which deal with 3D conditions. The whole work can be divided in to two parts. In the first part, a method to simulate the motion effect on a reference image is proposed to be applied. This method allows simulating the acquired images in a real dynamic test and estimating the measurement uncertainty caused by the motion effect. Using this technique, the uncertainty of DIC measurement is estimated. The second part of the study aimed to validate the simulation technique. Therefore, several tests are conducted by imposing harmonic motion to a target, in different frequencies and amplitudes. The results show good agreement between the experiments and the simulations, proving the introduced technique to be an effective method for motion induced uncertainty estimation. Author Affiliation: Politecnico di Milano, Dipartimento di Meccanica, via La Masa 1, 20156 Milano, Italy Article History: Received 12 July 2013; Revised 21 December 2013; Accepted 23 December 2013
    ISSN: 0143-8166
    Source: Cengage Learning, Inc.
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  • 6
    Language: English
    In: The Journal of Geology, 01 January 2011, Vol.119(1), pp.51-68
    Description: Abstract The mineralogy and chemical compositions of shale and sandstone alternations of Cretaceous age of the Monte Soro Unit, Sicily, have been determined. The clay minerals in the shales are mostly illite and I-rich mixed-layer I/S reflected by enrichment in Al 2 O 3 , K 2 O, and chemically similar elements. The sandstones are subarkose to quartz arenite. The shales and sandstones have upper-crustal rare earth element patterns, and except for K 2 O, they are depleted in alkaline and alkaline-earth elements as a result of intense weathering. The sandstone and shale mineralogy suggests a diagenetic history in which the sediments were subjected to temperatures in excess of 100°C, during which interaction between some minerals in the shales and sandstones took place. Thus, diagenetic quartz cementation and feldspar alteration in the sandstones and smectite illitization in the shales occurred together with the shales being a sink for potassium and the sandstones a sink for silicon. Negative europium anomalies ( between 0.45 and 0.87), (Gd/Yb) ch ratios (〈2, except for sample C1), and Sc/Cr versus La/Y and La-Th Sc diagrams suggest that the sedimentary rocks were derived from post-Archean granitoid-like rocks in a tectonically stable area. In addition, the foliated fabrics of polycrystalline quartz grains and the abundant phyllite rock fragments indicate a provenance from metamorphic rocks. The study of several trace element ratios (Ti/Zr, Cr/Zr, Y/Ni, Cr/V, Zr/Th, La/Th, La/Th, Cr/Th, Zr/Hf, Zr/Yb, Yb/Hf, V/La, La/Yb) strongly supports a local derivation from the European paleomargin.
    Keywords: Cretaceous Period -- Research ; Diagenesis (Geology) -- Research ; Sedimentary Rocks -- Research ; Geochemistry -- Research ; Petrology -- Research ; Weathering -- Research ; Shales -- Research ; Shales -- Properties ; Shales -- Composition ; Sandstone -- Research ; Sandstone -- Properties ; Sandstone -- Composition;
    ISSN: 00221376
    E-ISSN: 15375269
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  • 7
    Language: English
    In: Journal of Archaeological Science, 2011, Vol.38(11), pp.3060-3071
    Description: This work focuses on the petro-archaeometric analysis of several transport amphorae dated back from 4th to 2nd century BC which were found in various archaeological excavations recently carried out in Messina and Milazzo (north eastern Sicily). These amphorae, generally known as Graeco-Italic, raise the problem of the identification of their production areas. Petrographic analyses proved the presence of two groups characterised by the presence of coarse metamorphic or volcanic inclusions and one group with finer metamorphic inclusions. Multivariate statistical analyses made it possible to detect the production area of the amphorae with metamorphic inclusion in north eastern Sicily, comparing them with locally produced bricks and clay sediments cropping out near the ancient cities. On the contrary, the studied amphorae rich in volcanic inclusions have petrographic and chemical features which can be attributed to production areas in the Campanian region. ► Archaeometric analyses were performed on Graeco-Italic amphorae found in Sicily. ► The results have permitted to identify a production area located in north eastern Sicily. ► The importation of Graeco-Italic amphorae from the Campanian area were hypothised.
    Keywords: Graeco-Italic Amphorae ; Clayey Sediments ; Bricks ; Petrographic Analysis ; Xrf ; Multivariate Statistical Analysis ; History & Archaeology
    ISSN: 0305-4403
    E-ISSN: 1095-9238
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  • 8
    Language: English
    In: Optics and Lasers in Engineering, March 2015, Vol.66, pp.19-33
    Description: This paper discusses the effect of pre-processing image blurring on the uncertainty of two-dimensional digital image correlation (DIC) measurements for the specific case of numerically-designed speckle patterns having particles with well-defined and consistent shape, size and spacing. Such patterns are more suitable for large measurement surfaces on large-scale specimens than traditional spray-painted random patterns without well-defined particles. The methodology consists of numerical simulations where Gaussian digital filters with varying standard deviation are applied to a reference speckle pattern. To simplify the pattern application process for large areas and increase contrast to reduce measurement uncertainty, the speckle shape, mean size and on-center spacing were selected to be representative of numerically-designed patterns that can be applied on large surfaces through different techniques (e.g., spray-painting through stencils). Such “designer patterns” are characterized by well-defined regions of non-zero frequency content and non-zero peaks, and are fundamentally different from typical spray-painted patterns whose frequency content exhibits near-zero peaks. The effect of blurring filters is examined for constant, linear, quadratic and cubic displacement fields. Maximum strains between ±250 and ±20,000 µε are simulated, thus covering a relevant range for structural materials subjected to service and ultimate stresses. The robustness of the simulation procedure is verified experimentally using a physical speckle pattern subjected to constant displacements. The stability of the relation between standard deviation of the Gaussian filter and measurement uncertainty is assessed for linear displacement fields at varying image noise levels, subset size, and frequency content of the speckle pattern. It is shown that bias error as well as measurement uncertainty are minimized through Gaussian pre-filtering. This finding does not apply to typical spray-painted patterns without well-defined particles, for which image blurring is only beneficial in reducing bias errors.
    Keywords: Bias Error ; Digital Image Correlation ; Gaussian Filter ; Speckle Pattern ; Uncertainty ; Engineering ; Physics
    ISSN: 0143-8166
    E-ISSN: 1873-0302
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  • 9
    Language: English
    In: Applied Surface Science, 01 October 2013, Vol.282, pp.165-173
    Description: A self-cleaning photocatalytic coating based on TiO nanoparticles has been applied to and calcarenites. TiO sol was applied directly to the surface or after a SiO intermediate layer. Photocatalytic activity of the coatings (TiO and SiO /TiO ) was assessed under UV irradiation through methyl orange dye degradation tests. Good photodegradation activity and satisfactory compatibility between the sol and the surface of the investigated limestones is obtained. A self-cleaning photocatalytic coating for limestone materials, based on TiO nanoparticles obtained by the sol–gel process has been studied. TiO sol was applied directly to the surface or after a SiO intermediate layer. The selected test materials are the and the calcarenites, limestones of outcropping in the South Eastern Sicily (Italy). SEM–EDS, XRD and Raman investigations were carried out to characterise the TiO nanoparticles and coating. Nanocrystalline anatase and, to a lesser extent, brookite forms are obtained. To evaluate the harmlessness of the treatment, colorimetric tests, water absorption by capillarity and crystallisation of salts measurements were performed. Photocatalytic activity of the TiO colloidal suspension and of the coatings (TiO and SiO /TiO ) was assessed under UV irradiation through methyl orange dye degradation tests. The results show good photodegradation activity and satisfactory compatibility between the sol and the surface of the investigated limestones.
    Keywords: Sol–Gel Titania ; Nano-Sized Tio2 ; Limestone ; Self-Cleaning Coating ; Photocatalysis ; Anatase and Brookite ; Engineering
    ISSN: 0169-4332
    E-ISSN: 1873-5584
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  • 10
    Language: English
    In: Computers and Geosciences, Nov, 2014, Vol.72, p.49(16)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.cageo.2014.07.006 Byline: Gaetano Ortolano, Luigi Zappala, Paolo Mazzoleni Abstract: A new semi-automated image processing procedure based on multivariate statistical analysis of X-ray maps of petrological and material science interest has been developed to generate high contrast pseudo-coloured images highlighting the element distribution between and within detected mineral phases. This new tool package, developed in Python and integrated with ArcGis.sup.[R], generates in only a few minutes several graphical outputs useful for classifying chemically homogeneous zones as well as extracting quantitative information through the statistical data handling of X-ray maps. The code, largely based on the use of functions implemented in ArcGis.sup.[R] 9.3 equipped with Spatial Analyst and Data Management licences, has been suitably integrated with original cyclic functions that hugely reduce the time taken to complete lengthy procedures. In particular these tools, after the acquisition of any kind of multispectral images allow fast and powerful data processing for efficient illustration and documentation of key compositional and microtextural relationships in rocks and materials. Author Affiliation: Department of Biological, Geological and Environmental Science, University of Catania, Corso Italia, 57, 95125 Catania, Italy Article History: Received 23 October 2013; Revised 2 July 2014; Accepted 3 July 2014
    ISSN: 0098-3004
    Source: Cengage Learning, Inc.
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