892 resultados para sheet metal work


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The mechanical forming processes are the main means of transformation. Among all processes, the most used is rolling and broken down into flat and non-flat products. In the flat products are classified plates, and products no plans bars and profiles. Thus laminating products, mostly, are the raw materials for other processes of transformation, as stamping, forging, machining, bending and more. This work has focused on non-flat products, classified as bars and rods, watching a key point in the proceedings that is the product quality. Here is demonstrated through metallographic analysis of steel bars, hot-rolled, the characteristics of surface cracks in these bars

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Pós-graduação em Engenharia Mecânica - FEG

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The Wilkes and Aurora basins are large, low-lying sub-glacial basins that may cause areas of weakness in the overlying East Antarctic ice sheet. Previous work based on ice-rafted debris (IRD) provenance analyses found evidence for massive iceberg discharges from these areas during the late Miocene and Pliocene. Here we characterize the sediments shed from the inferred areas of weakness along this margin (94°E to 165°E) by measuring40Ar/39Ar ages of 292 individual detrital hornblende grains from eight marine sediment core locations off East Antarctica and Nd isotopic compositions of the bulk fine fraction from the same sediments. We further expand the toolbox for Antarctic IRD provenance analyses by exploring the application of 40Ar/39Ar ages of detrital biotites; biotite as an IRD tracer eliminates lithological biases imposed by only analyzing hornblendes and allows for characterization of samples with low IRD concentrations. Our data quadruples the number of detrital 40Ar/39Ar ages from this margin of East Antarctica and leads to the following conclusions: (1) Four main sectors between the Ross Sea and Prydz Bay, separated by ice drainage divides, are distinguishable based upon the combination of 40Ar/39Ar ages of detrital hornblende and biotite grains and the e-Nd of the bulk fine fraction; (2) 40Ar/39Ar biotite ages can be used as a robust provenance tracer for this part of East Antarctica; and (3) sediments shed from the coastal areas of the Aurora and Wilkes sub-glacial basins can be clearly distinguished from one another based upon their isotopic fingerprints.

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A Laser Scanner System (LSS) produces a photoresponse map and can be used for the nondestructive detection of nonuniformities in the photoresponse of a semiconductor device. At SERI the photoresponse maps are used to identify solar cell faults including microcracks, metallization breaks, regions of poor contact between metallization and the underlying emitter surface, and variations in emitter sheet resistance.

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Mode of access: Internet.

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Mode of access: Internet.

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Mode of access: Internet.

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Mode of access: Internet.

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Mode of access: Internet.

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-[pt. I] Mechanical drawing, by E. Kenison. Shades and shadows, by H. W. Gardner. Perspective drawing, by W. H. Lawrence. Freehand drawing, by H.E. Everett. Pen and ink rendering, by D. A. Gregg. Rendering in wash, by H. V. von Holst. Architectural lettering, by F. C. Brown.- [pt. 2] - Mechanical drawing, by E. Kenison. Working drawings, machine design, by C. L. Griffin. Sheet metal pattern drafting, tinsmithing, practical problems in mensuration, by W. Neubecker.

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Latest issue consulted: Vol. 160, no. 4059 (20 Sept. 2002).