First-principles investigation of magnetism and electronic structures of substitutional 3d3d transition-metal impurities in bcc Fe

The magnetic and electronic structures of $3d$ impurity atoms from Sc to Zn in ferromagnetic body-centered cubic iron are investigated using the all-electron full-potential linearized augmented plane-wave method based on the generalized gradient approximation (GGA). We found that in general, the GGA results are closer to the experimental values than those of the local spin density approximation. The calculated formation enthalpy data indicate the importance of a systematic study on the ternary Fe-C-$X$ systems rather than the binary Fe-$X$ systems, in steel design. The lattice parameters are optimized and the conditions for spin polarization at the impurity sites are discussed in terms of the local Stoner model. Our calculations, which are consistent with previous work, imply that the local spin-polarizations at Sc, Ti, V, Cu, and Zn are induced by the host Fe atoms. The early transition-metal atoms couple antiferromagnetically, while the late transition-metal atoms couple ferromagnetically, to the host Fe atoms. The calculated total magnetization ($M$) of bcc Fe is reduced by impurity elements from Sc to Cr as a result of the antiferromagnetic interaction, with the opposite effect for solutes which couple ferromagnetically. The changes in $M$ are attributed to nearest neighbor interactions, mostly between the impurity and host atoms. The atom averaged magnetic moment is shown to follow generally the well-known Slater-Pauling curve, but our results do not follow the linearity of the Slater-Pauling curve. We attribute this discrepancy to the weak ferromagnetic nature of bcc Fe. The calculated Fermi contact hyperfine fields follow the trend of the local magnetic moments. The effect of spin-orbit coupling is found not to be significant although it comes into prominence at locations far from the impurity sites.Comment: 26 pages, 11 figure

The Effect of Growth Promoting Implants on Feedlot Performance by Gelbvieh Bulls

The objective of this research was to determine the effect on feedlot performance of implanting various growth promotants in young bulls. Responses to these various implants by bulls were compared to a control group of bulls to determine the differences in feedlot performance. These comparisons provide information to help determine the most effective methods of bull feeding

Chemical reactivity of hydrogen, nitrogen and oxygen atoms at temperatures below 100 deg K Fifth semiannual technical report

Chemical reactivity of hydrogen, nitrogen, and oxygen atoms at temperatures below 100 deg

Implant Combinations and Reimplanting Strategies for Yearling Steers Fed High Concentrate Diets

Crossbred yearling steers were used to determine the relative efficacy of specific anabolic implant combinations and sequences on feedlot performance and carcass traits. Steers were fed a high concentrate finishing diet for 112 days. lmplanting was done on days 1 and 42 of the feeding period. lmplanting improved (P \u3c .05) average daily gain (ADG) 22% and feed efficiency 15%. Implant treatment generally increased dry matter intake. Lmplanting increased (P\u3c.05) the rib eye area of carcasses 6.5% and tended to cause a reduction in percentage choice carcasses. The percentage of abscessed implants ranged from \u3c 1 % to 10%, depending on the type of implant used even though implant needles were disinfected between each use

The Effect of Synovex-S Implants on Feedlot Performance of Angus Bulls and Early Feedlor Period Castrated Angus Bulls

The objective of this research was to determine the effect on feedlot performance of implanting bulls and steers with Synovex-S, and comparing steers to bulls. Profit or loss upon marketing was also studied. Responses to these treatments in terms of feedlot performance provide information to help determine the most effective method of feeding bulls or steers and revenue in dollars upon sale assists in determining the best management scheme for profit

Effects of Sex and Hormonal Implant on Beef Carcass Characteristics and Palatability

A comparison of crossbred bulls, steers and heifers indicated that bulls have heavier carcasses, larger rib eyes and a more desirable yield grade. The USDA quality grade of the bulls was one-third of a grade lower than for the steers and heifers. The sensory and palatability characteristics showed no significant differences among axes. Implanted bulls as compared to non-implanted bulls showed more desirable taste panel scores for tenderness, juiciness and overall panel desirability

The Effects of Breed and Implant on Bullock Beef

Ninety-seven Angus and 98 Gelbvieh crossbred bulls were used to evaluate the effects of Ralgro, Synovex-H and Synovex-S implants on the growth, carcass and palatability traits of young bulls. The influence of the growth promoting implants on the feedlot performance of the bulls was dependent on their breed type and their stage growth. Percentage retail yield was the only carcass characteristic that was affected by the implants. The implanted bulls yielded carcasses with more external fat and less desirable yield grades than the controls. Rib eye area was not affected by the implants. Breed influenced feedlot performance, carcass composition and quality and palatability attributes more than the implants. The large-framed, late maturing Gelbvieh crossbred bulls grew faster and produced carcasses yielding higher percentages of boneless and produced carcasses yielding higher percentages of boneless trimmed retail cuts than the Angus bulls. The quality grades and palatability traits of the Gelbvieh bulls were marginal. The Angus bull carcasses has very acceptable yield grades (YG-2) and more desirable quality grades and sensory evaluations than the Gelbvieh crossbred bulls. Thus, the use of medium-framed intact males may be more appropriate than the larger framed breeds to produce a more acceptable product for both the packer and the consumer. Packer acceptability needs to be enhanced to make the use of intact males economically feasible for the producer

Stick-Slip Motion and Phase Transition in a Block-Spring System

We study numerically stick slip motions in a model of blocks and springs being pulled slowly. The sliding friction is assumed to change dynamically with a state variable. The transition from steady sliding to stick-slip is subcritical in a single block and spring system. However, we find that the transition is continuous in a long chain of blocks and springs. The size distribution of stick-slip motions exhibits a power law at the critical point.Comment: 8 figure