Interfacial phenomena in steel fibre reinforced cement II: Pull-out behaviour of steel wires

This paper describes a study of the processes involved at and near the steel-matrix interface when an embedded steel wire is pulled out of a cement paste or mortar matrix. Prior to debonding, shrinkage leads to micro-cracking of the matrix which in turn reduces the stress transfer at the interface. The behaviour after debonding, which constitutes the major part of the study, is again markedly non-linear. This arises from compaction of the cement paste in the vicinity of the wire and is produced by the pull-out process itself. The compaction is more marked with rougher wires and occurs to a greater degree with cement paste than with mortars.     

Choledochal cyst: a review of 19 cases

Nineteen cases of choledochal cyst are reviewed. Two distinct groups of patients were identified. Patients under one year of age, initially diagnosed as having biliary atresia, had a higher mortality rate, a higher incidence of severe cirrhosis with portal hypertension, and associated atresia or stenosis in the biliary tree. The second group, presenting between 3 and 20 years of age with more classic symptoms, had mild cirrhosis without portal hypertension and had associated choledocholithiasis and pancreatitis. It is suggested that the younger patients had a congenital form of cystic bile duct dilatation and that the older patients had an acquired form, perhaps related to a common channel with reflux of pancreatic juice into the common bile duct. Postoperative follow-up supports the current view that choledochocyst-jejunostomy with choleystectomy has a lower rate of long-term complications than does choledochocyst-duodenostomy.     

Solar radiation changes at Mt. St. Katherine after forty years

Between 1933 and 1937 Dr. Abbot and his co-workers from the Smithsonian Institution made normal incidence measurements atop Mt. St. Katherine in the Sinai. The observations made at that time indicated a very clean atmosphere prevailed on clear days. Measurements made forty years later with newer instruments and one of the original silver disks used by Dr. Abbot indicates a loss of some 10 per cent of the solar energy contained in the direct beam.     

Evolution of polyphenolic compounds in red wine from Cabernet Sauvignon grapes processed by pulsed electric fields during aging in bottle

The evolution of the Folin–Ciocalteu index, colour intensity and the principal individual polyphenols throughout 12 months of aging in bottles of red wine from Cabernet Sauvignon grapes treated and untreated by pulsed electric fields (PEF) have been compared. PEF technology allowed bottling of wines with higher Folin–Ciocalteu index, colour intensity and individual polyphenols concentrations using a shorter maceration time. For both wines, aging did not affect the colour intensity, whereas the Folin–Ciocalteu index decreased. The evolution of the principal individual polyphenols during the 12 months of storage followed a similar pattern in both wines. At the end of aging, there were no significant differences observed in the content of monomeric anthocyanins between both wines, however, the content of flavan-3-ols, flavonols and hydroxycinnamic acids and derivatives was higher in PEF treated wine. These results indicate that PEF could be a suitable technology for obtaining wines with higher phenolic content or reducing the maceration time during vinification.     

Near-real-time combustion monitoring for PCDD/PCDF indicators by GC-REMPI-TOFMS

The boiler exit flue gas of a municipal waste combustor was sampled to evaluate an online monitoring system for chlorobenzene congeners as indicators of polychlorinated dibenzodioxin and dibenzofuran (PCDD/PCDF) concentrations. Continuous measurements of chlorobenzene congeners using gas chromatography coupled to a resonance-enhanced multiphoton ionization - time-of-flight mass spectrometry (GC-REMPI-TOFMS) system were compared over 5-min periods with conventional sampling methods for PCDD/PCDF. Three pairs of values were taken every hour over a period of three days to characterize the combustor's response to transient operating conditions (shutdowns and startups). Isolation of specific chlorobenzene congeners from other same-mass compounds was accomplished by using a GC column separator ahead of the REMPI-TOFMS. The 50-fold variation of PCDD/PCDF concentration was paralleled by similar changes in monitored compounds of 1,4-dichlorobenzene, 1,2,4-trichlorobenzene, 1,2,3-trichlorobenzene, and 1,2,4,5-tetrachlorobenzene. A correlation of R = 0.85 and 0.89 was established between 40 pairs of simultaneous 5-min GC-REMPI-TOFMS measurements of 1,2,4-trichlorobenzene and 5 min conventional sampling and analysis for the TEQ and Total measures of PCDD/PCDF, respectively. The GC-REMPI-TOFMS system can be used to provide frequent measures of correlative PCDD/PCDF concentration thereby allowing for an understanding of measures to minimize PCDD/PCDF formation and develop operational feedback to limit emissions.