Effect of an absorbent overlay on the residual stress field induced by laser shock processing on aluminum samples

Abstract

Twenty-eight Holstein cows (4 with ruminal cannulas) were blocked by days in milk into 7 groups and then randomly assigned to 1 of 7 balanced 4 4 Latin square diet sequences. The diets contained [dry matter (DM) basis] 20% alfalfa silage, 35% corn silage, and 45% concentrate mainly from high-moisture corn and soybean meal. Diets differed in crude protein (CP) content and source of protein supplement: diet A) 15.6% CP, 3.7% solvent-extracted soybean meal (SSBM), 4.5% expeller soybean meal (ESBM); diet B) 16.6% CP, 9.6% SSBM, 0% ESBM; diet C) 16.6% CP, 4.6% SSBM, 5.9% ESBM; and diet D) 17.6% CP, 11.7% SSBM, 0% ESBM. Each experimental period consisted of 14 d for adaptation plus 14 d for collection of production data. Sampling of ruminal digesta and spot sampling of blood, feces, and urine was done on d 26 and 27 of each period. Planned contrasts compared included diet A vs. diet B, diet B vs. diet C, and diet B vs. diet D. There were no effects of diet on most of the production traits measured. However, milk yield tended to be higher for diet B vs. A. Trends were also detected for higher DM intake and weight gain and lower milk yield/DM intake in cows fed diet D vs. diet B. Milk lactose content was higher on diets A and C than on B. Ruminal NH3 was higher on diet D vs. B, but other ruminal metabolites, apparent nutrient digestibility, and estimated bacterial CP synthesis did not differ across diets. Blood and milk urea-N were higher on diets C and D than on B; milk urea-N was higher on diet B than on A. Increasing dietary CP from 16.6% (diet B) to 17.6% (diet D) increased urinary N excretion by 54 g/d and reduced apparent N efficiency (milk N/N intake) by 2.5 percentage units, without altering yield. Under the conditions of this trial, milk production was not improved by feeding rumen-undegraded protein from ESBM or greater amounts of rumen-degraded protein from SSBM. Feeding more than 16.6% CP depressed N efficiency. " American Dairy Science Association, 2006.",,,,,,,,,"http://hdl.handle.net/20.500.12104/40902","http://www.scopus.com/inward/record.url?eid=2-s2.0-33745897923&partnerID=40&md5=3917c3ccd70d6baa5293f4cd0bf40eed",,,,,,"5",,"Journal of Dairy Science",,"1635

1643",,"89",,"Scopus",,,,,,"Dietary crude protein; Nitrogen excretion; Nitrogen metabolism; Soybean protein",,,,,,"Effect of amount and ruminal degradability of soybean meal protein on performance of lactating dairy cows",,"Article" "42682","123456789/35008",,"Rubio-González, C., Centro de Ingeniería y Desarrollo Industrial, Pie de la Cuesta No. 702, Desarrollo San Pablo, Queretaro, Mexico; Gomez-Rosas, G., Departamento de Ciencias Exactas y Tecnológicas, Centro Universitario de los Lagos, Universidad de Guadalajara. Lagos de Moreno Jal., Mexico; Ocaña, J.L., Departamento de Física Aplicada a la Ingeniería Industrial, E.T.S.I.I. Universidad Politécnica de Madrid, Spain; Molpeceres, C., Departamento de Física Aplicada a la Ingeniería Industrial, E.T.S.I.I. Universidad Politécnica de Madrid, Spain; Banderas, A., Centro de Ingeniería y Desarrollo Industrial, Pie de la Cuesta No. 702, Desarrollo San Pablo, Queretaro, Mexico; Porro, J., Departamento de Física Aplicada a la Ingeniería Industrial, E.T.S.I.I. Universidad Politécnica de Madrid, Spain; Morales, M., Departamento de Física Aplicada a la Ingeniería Industrial, E.T.S.I.I. Universidad Politécnica de Madrid, Spain",,"Rubio-Gonzalez, C.

Gomez-Rosas, G.

Ocana, J.L.

Molpeceres, C.

Banderas, A.

Porro, J.

Morales, M.",,"2006",,"Laser shock processing (LSP) or laser shock peening is a new technique for strengthening metals. This process induces a compressive residual stress field, which increases fatigue crack initiation life and reduces fatigue crack growth rate. Specimens of 6061-T6 aluminum alloy are used in this investigation. A convergent lens is used to deliver 2.5 J, 8 ns laser pulses by a Q-switch Nd:YAG laser, operating at 10 Hz. The pulses are focused to a diameter of 1.5 mm onto aluminum samples. Density of 2500 pulses/cm2 with infrared (1064 nm) radiation was used. The effect of an absorbent overlay on the residual stress field using this LSP setup and this energy level is evaluated. Residual stress distribution as a function of depth is assessed by the hole drilling method. It is observed that the overlay makes the compressive residual stress profile move to the surface. This effect is explained on the basis of the vaporization of the coat layer suppressing thermal effects on the metallic substrate. The effect of coating the specimen surface before LSP treatment may have advantages on improving wear and contact fatigue properties of this aluminum alloy. " 2005 Elsevier B.V. All rights reserved.