Deflectometric Measurement of Specular Surfaces

Even small variations of the curvature of a surface may cause malfunction of a part or be perceived as visually unpleasant. However, in the case of specular and painted surfaces, curvature defects can hardly be detected with traditional measurement methods like triangulation or stereoscopy. We describe new strategies to measure the curvature of such surfaces based on deflectometry. This technique mimics the behavior of a human observer by using the object under examination as a mirror. By analyzing its imaging properties, a partial inference on the surface shape is possible. With this approach, much better results can be achieved as compared with triangulation methods. Furthermore, a reliable measurement of defects showing depths of only a few micrometers is enabled.     

APPLICATIN OF ATTRITION GRINDING IN ACID LEACHING OF NICKEL SULFIDE CONCENTRATE

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Bed performance in the direct electrowinning of lead from suspension galena anodes

Additive effects have been examined in the performance of suspension electrolysis of galena concentrate anode. A better conducting additive of properly selected size fraction, compatible with the relative size and specific gravity of galena, was found to improve the dissolution characteristics. With optimization of parameters such as current density, lead ion additions to the bath, electrolysis time,etc., and by withdrawing accumulated elemental sulfur intermittently, it was possible to dissolve lead with 79 pct current efficiency and energy consumption of 0.54 Kwh per kilogram of lead.     

Factors affecting stall use for different freestall bases

The objective of this study was to compare stall use (stall occupancy and cow position) by barn side for factors affecting stall use. A closed circuit television system recorded stall use four times per day for a 9-mo period starting May 9, 2001. Six factors were analyzed: stall base, distance to water, stall location within stall base section, stall location within barn, inside barn temperature, and length of time cows were exposed to stall bases. Two barn sides with different stocking densities were analyzed: low (66%), with cows milked by robotic milker; and high (100%), with cows milked 2X in parlor. Six stall base types were tested: two mattresses, a waterbed, a rubber mat, concrete, and sand (high side only). The base types were grouped 3 to 7 stalls/section and randomly placed in each row. Cows spent more time in mattress-based stalls, but the highest percentage lying was in sand-based stalls. The following significant stall occupancy percentages were found: sand had the highest percentage of cows lying on the high stocking density side (69%), followed by mattress type 1 (65%) > mattress type 2 (57%) > waterbed (45%) > rubber mat (33%) > concrete (23%). Mattress type 1 had the highest percentage stalls occupied (88%), followed by mattress type 2 (84%) > sand (79%) > soft rubber mat (65%) > waterbed (62%) > concrete (39%). On the low stocking rate side, mattress type 1 had the highest percentage cows lying (45%) and occupied (59.6%), followed by mattress type 2 > waterbed > soft rubber mat > concrete. Cow lying and stalls occupied percentages were highest for stalls 1) not at the end of a section, and 2) on the outside row, and varied by base type for time cows exposed to stalls and inside barn temperature. Lying and occupied percentages were different for different mattress types. The percentage of stalls with cows standing was higher for mat and mattress-based stalls. Results show mattress type 1 and sand to be superior and rubber mats and concrete inferior stall bases.