Durability of simulated DWPF annealed glasses

Simulated high-level waste glass samples of the DWPF projected compositions were annealed at various times and temperatures in order to develop time-temperature-transformation diagrams. These heat treated glasses were subjected to the Product Consistency Test (PCT) to evaluate glass durability. The B, Li, and Na concentrations in the leachate (the PCT results) were compared to the PCT results of the Environmental Assessment benchmark glass. Durability as a function of glass composition and crystallinity was also examined

Performing a chemical durability test on radioactive high-level nuclear waste glass

Savannah River Site (SRS), currently is storing {approximately}30 million gallons of highly radioactive nuclear wastes. The Defense Waste Processing Facility (DWPF) nearing completion at SRS will incorporate the radionuclides in these wastes into solid borosilicate glass for final disposal in a geologic repository. Because of the variability of the wastes in the tanks, borosilicate glasses of different compositions will be produced by the DWPF during the 20--25 years required to solidify all the wastes at SRS. A chemical durability test, the Product Consistency Test (PCT), has been developed at SRS to measure the consistency of the durability of these glasses. This paper describes the remote and hands-on procedures for performing the PCT on these radioactive glasses. Results will be presented that indicate the good precision of the PCT and indicate some of the chemistry involved in leaching radioactive elements from the glass. 9 refs., 1 fig., 4 tabs

Multiple correlation analyses of metabolic and endocrine profiles with fertility in primiparous and multiparous cows

Results from 4 studies were combined (representing a total of 500 lactations) to investigate the relationships between metabolic parameters and fertility in dairy cows. Information was collected on blood metabolic traits and body condition score at 1 to 2 wk prepartum and at 2, 4, and 7 wk postpartum. Fertility traits were days to commencement of luteal activity, days to first service, days to conception, and failure to conceive. Primiparous and multiparous cows were considered separately. Initial linear regression analyses were used to determine relationships among fertility, metabolic, and endocrine traits at each time point. All metabolic and endocrine traits significantly related to fertility were included in stepwise multiple regression analyses alone (model 1), including peak milk yield and interval to commencement of luteal activity (model 2), and with the further addition of dietary group (model 3). In multiparous cows, extended calving to conception intervals were associated prepartum with greater concentrations of leptin and lesser concentrations of nonesterified fatty acids and urea, and postpartum with reduced insulin-like growth factor-I at 2 wk, greater urea at 7 wk, and greater peak milk yield. In primiparous cows, extended calving to conception intervals were associated with more body condition and more urea prepartum, elevated urea postpartum, and more body condition loss by 7 wk. In conclusion, some metabolic measurements were associated with poorer fertility outcomes. Relationships between fertility and metabolic and endocrine traits varied both according to the lactation number of the cow and with the time relative to calving

Effect of dietary enrichment with either n-3 or n-6 fatty acids on systemic metabolite and hormone concentration and ovarian function in heifers

The objective of this experiment was to examine the effects of dietary n-3 or n-6 fatty acid (FA) supplementation on blood FA, metabolite and hormone concentrations, follicle size and dynamics and corpus luteum (CL) size. Reproductively normal heifers (n = 24) were individually fed diets of chopped straw and concentrate containing either (i) no added lipid (CON; n = 8), (ii) 2% added fat as whole raw soya beans (WSB, n-6; n = 8), or (iii) 2% added fat as fish oil (FO, n-3; n = 8). Following oestrous cycle synchronisation, blood samples were collected at appropriate times and intervals for the measurement of hormones, FAs and metabolites. On days 15 and 16 of the cycle, animals were subjected to an intravenous oxytocin challenge and prostaglandin F-2 alpha (PGF(2 alpha) response, measured as venous concentrations of 13,14-dihydro-15-keto PGF(2 alpha) (PGFM). Dry matter intake and average daily gain were similar among treatments (P > 0.05). Plasma concentration of linoleic acid was highest on WSB (P 0.05). There was a diet X day interaction for PGFM (P 0.05). Concentrations of PGFM on day 16 were similar for WSB and FO and were greater than CON at 15 (P < 0.01) and 45 min (P < 0.05) post oxytocin administration, and at 30min for FO (P < 0.05). With the exception of PGFM, dietary lipid source did not affect the reproductive variables measured