Engineering near infrared single photon emitters in ultrapure silicon carbide

Quantum emitters hosted in crystalline lattices are highly attractive candidates for quantum information processing, secure networks and nanosensing. For many of these applications it is necessary to have control over single emitters with long spin coherence times. Such single quantum systems have been realized using quantum dots, colour centres in diamond, dopants in nanostructures and molecules . More recently, ensemble emitters with spin dephasing times on the order of microseconds and room-temperature optically detectable magnetic resonance have been identified in silicon carbide (SiC), a compound being highly compatible to up-to-date semiconductor device technology. So far however, the engineering of such spin centres in SiC on single-emitter level has remained elusive. Here, we demonstrate the control of spin centre density in ultrapure SiC over 8 orders of magnitude, from below $10^{9}$ to above $10^{16} \,$cm$^{-3}$ using neutron irradiation. For a low irradiation dose, a fully photostable, room-temperature, near infrared (NIR) single photon emitter can clearly be isolated, demonstrating no bleaching even after $10^{14}$ excitation cycles. Based on their spectroscopic fingerprints, these centres are identified as silicon vacancies, which can potentially be used as qubits, spin sensors and maser amplifiers.Comment: 5 pages, 4 figure

Feeding DDGS to Finishing Pigsin Deep-Bedded Hoop Barns

The ethanol industry in Iowa has rapidly expanded in the last several years. A major coproduct of ethanol production is dried distillers grains with solubles(DDGS). Higher prices for corn and ample supplies of DDGS has generated interest in feeding DDGS to finishing pigs. Challenges in feeding DDGS supplemented diets to finishing swine include problems of feed flowability in bulk bins and feeders, reduced feed intake, and softer, oilier fat in pork carcasses. Pelleted diets have improved flowability and may stimulate feed intake, but thus far no studies have examined feeding DDGS-supplemented dietsin pelletted form to pigs. The objective of this study was to evaluate pelletted DDGS-based diets fed to finishing pigs

Maximizing DDGS for Finishing Pigs in Bedded Hoop Barns

Higher prices for corn and increasing supplies of DDGS have generated questions about feeding DDGS to market swine. The objective of this study was to evaluate various programs to maximize DDGS feeding to finishing pigs in bedded hoop barns. The project was conducted during 2008 and 2009 at the ISU Western Research Farm, Castana, IA. The pens were in small hoop barns with two pens per barn. Each pen was assigned to one of three dietary treatments— continuous 20% DDGS (Cont), a step-up program from 0% to 30% DDGS (Step), and a high DDGS program that rapidly got pigs to 30% DDGS (High). All treatments were fed a 20% DDGS diet for the last phase of the trial. There were 4 dietary phases in the 98-day trial. Phase 1 and 4 were each 21d. Phase 2 and 3 were each 28d. The diets were pelletted and fed ad libitum. Within each phase, the diets were formulated to be equal in apparent digestible amino acids—lysine, threonine, and tryptophan. The pigs consumed the diets readily with no apparent problems making the transition among the diets. Feed intake (ADFI), growth (ADG), and feed per liveweight gain (F/G) did not differ among treatments (P \u3e 0.05). No major differences were noted in backfat thickness (BF) and loin muscle area (LMA) (P \u3e 0.05). Also, based on the means of fatty acid saturation, iodine values, and belly flop scores of selected pigs in trial (one, two or three), the differences in unsaturation percentages, iodine value and belly flop scores between treatments were minor. On average, a pig fed the continuous program consumed 119 lb of DDGS or 20% of the total feed over the 98-day feeding trial (from 54 to 274 lb). A pig fed the Step-up program consumed 106 lb of DDGS or 17% of the total feed. A pig fed the High program consumed 162 lb of DDGS or 26% of the total feed. This work suggests that diets and feeding programs can be designed to increase DDGS usage by market swine without negatively affecting pig performance. Also formulating diets on apparent digestible amino acid content may be advantageous when using DDGS on swine diets. The pelleted diets worked well with no problems in feed flow or fines separation

Maximizing DDGS for Finishing Pigs in Bedded Hoop Barns: Trial One

Iowa’s ethanol industry continues to expand rapidly. A major coproduct of ethanol production is dried distillers grains with solubles (DDGS). Higher prices for corn and increasing supplies of DDGS have generated questions about feeding DDGS to market swine. The objective of this study was to evaluate various programs to maximize DDGS feeding to finishing pigs in bedded hoop barns. The work reported is the first of several trials planned

Returns and Costs of Niche Pork Production in 2006

Production of niche pork has been expanding in response to growing demand. Little information is known about the costs and returns from niche pork production. This report provides information on cost and returns for 41 niche pork producers. Return levels show that the average return to capital, unpaid labor and management for the top 15 producers was $17.43 per hundred pounds of pork produced, while this average was$2.17 for the bottom 15 producers and $10.08 for all 41 producers. The average margin over all costs on a per head sold basis was slightly below breakeven (-$2.36) for all 41 producers. The average return per hour of labor after all costs was $13.17 for all 41 producers, but$22.66 per hour for the top 15 producers and $3.02 for the bottom 15 producers. The average total cost per hundred pounds of pork produced for all producers was$52.05, while the top 15 third had average total costs that were $11.17 less than the bottom 15 producers ($46.05 vs. $57.22). The main contributor to cost differences between the top third and bottom third producers was operating costs, which included feed and other operating expenses but not labor. These costs represented 96 percent of the total cost difference, with 56 percent of this difference being in other operating costs and 40 percent in feed costs

Efficiency of Niche Pork Production in 2006

Production of niche pork has been expanding in response to increased demand. Little information is known about production efficiency of niche pork. This report provides information on production efficiency from 41 niche pork producers. The average female breeding herd size was 91 females. The average feed efficiency was 4.31 pounds of feed per pound of pork produced. The average feed efficiency for the top 15 herds was 3.74 and it was 4.25 for the bottom 15 herds. Average labor use was .87 hours per hundred pounds of pork produced. About one of every four pigs born alive died before weaning. Another eight percent died from weaning to market. Breeding herd death loss was in the 4 to 6 percent range. The information summarized here shows striking production differences in many areas between the top 15 and bottom 15 producers. The areas with the largest differences are places with the most potential to help producers improve. Educational programming that targets these areas is being developed to help these producers make changes to improve their operations, which in turn will improve the position of this sector of the industry

Returns and Costs of Niche Pork Production in 2008

Information is provided on the return, cost and financial efficiency for niche pork production. Information from 18 niche pork producers is included in the analysis. Return levels showed that the average return to capital, unpaid labor and management return to capital, unpaid labor and management for the top 6 producers was $5.23 per hundred pounds of pork produced, while this average was -$10.68 for the bottom 6 producers and -$3.80 for all 18 producers. The average margin over all costs on a per head sold basis showed a large loss ($-52.89 for the average producer). The average return per hour of labor after all costs was -$12.36 for all 18 producers, but$9.23 per hour for the top 6 producers and -$9.82 for the bottom 6 producers. The average total cost per hundred pounds of pork produced for all producers was$81.40, while the top third (6) had average total costs that were $32.43 less than the bottom 6 producers ($66.52 vs $98.75). Production costs increased by about 21 percent over the 2007 level. The main contributor to cost differences between the top third and bottom third producers was operating costs, which included feed and other operating expenses and labor costs. These costs represented the majority of the total cost difference and were about equally split between the two; operating costs (feed and other) and labor costs. The information summarized here shows striking differences in many areas between the top 6 and bottom 6 producers. The areas with the largest differences are places with the most potential to help producers improve. Educational programming that targets these areas is being developed to help these producers make changes to improve their operations, which in turn will improve the position of this sector of the industry

Growth Performance and Ultrasonic Scan of Purebred Berkshire Pigs Housed in Hoop Buildings in Iowa (Trials 3 and 4)

A certified Berkshire program continues to lead niche pork production markets based on its meat quality advantage over commodity-based pork. This economic advantage is especially valuable for smaller, more traditional pork producers. The disadvantages of Berkshire pigs are fatter carcasses, slower gains, and less efficient feed conversion compared with commodity pork production. Consequently, these pigs are often a better fit for less intensive or lower production systems

Efficiency of Niche Pork Production in 2007

Information is provided on pig production efficiency for niche pork production. Information from 27 niche pork producers is included in the analysis. The average female breeding herd size was 81 females. The average feed efficiency was 4.42 pounds of feed per pound of production, although the average for the top 9 herds was 3.78 and the average for the bottom 9 herds was 5.24. Average labor use was 1.01 hours per hundred pounds of pork produced. About one of every four pigs born alive died before weaning. Another 13 percent died from weaning to market. Breeding herd death loss was in the 4 to 12 percent range. The information summarized here shows striking differences in many areas between the top 9 and bottom 9 producers. The areas with the largest differences are places with the most potential to help producers improve. Educational programming that targets these areas is being developed to help these producers make changes to improve their operations, which in turn will improve the position of this sector of the industry