Experimental Study on the Aging of Sands

Aging effects in sand, such as increases in cone penetration resistance with time after deposition and/or densification, are known to occur in the field, but the causes of these effects are not fully understood. A laboratory testing program was designed to study mechanisms responsible for aging effects under controlled conditions. The testing program included measurements of the small strain shear modulus, electrical conductivity, pore fluid chemistry, and minicone penetration resistance after different periods of aging. Two different sands were tested, and aging effects were evaluated for different combinations of relative density, temperature, and pore fluid composition. Increases in the small strain shear modulus were observed throughout most of the tests, and chemical analyses suggest that precipitation of carbonate and silica occurred in two tests. Despite these changes, there was no corresponding increase in the minicone penetration resistance with time in any of the tests. It is unlikely that precipitation of carbonate or silica is responsible for aging effects in sands; other possible mechanisms include arching due to dissipation of blast gases and redistribution of stresses through the soil skeleton. An additional possibility is that the boundary conditions imposed by the laboratory tests obscure changes in penetration resistance that would be measured had the volume of sand tested been much larger. The implications of these findings in terms of other published field and laboratory studies are discussed.     

High-Modulus Columns for Liquefaction Mitigation

This paper presents the performance of a shopping complex in Turkey where the soils were improved with jet-grout columns and preload fills and subjected to the 1999 Kocaeli Earthquake (M = 7.4). Under construction at the time of the earthquake, the Carrefour Shopping Center covers an area of 55,000?m2 and is founded on shallow footings, mats, and slabs-on-grade that rest on soft, saturated alluvial sediments consisting of clays, silts, and sands. High-modulus columns constructed by jet grouting were installed at close-to-moderate spacings to reduce anticipated static settlements in the clays and mitigate liquefaction in the sands. The site was subjected to a peak acceleration of approximately 0.2g during the earthquake. Grouting had been completed for about two-thirds of the site when the earthquake struck. Following the event, a field reconnaissance found stark contrast between the performance of the improved and unimproved sections. The jet-grout-treated areas suffered no apparent damage, whereas the unimproved sections of the complex, along with nearby untreated building sites, commonly suffered liquefaction-related settlements of up to 10 cm. This is the only case history known to the authors that documents the field performance of high-modulus columns used in this manner for liquefaction mitigation and direct instrumented measurement of liquefaction-induced settlements.     

A correlation coefficient for intuitionistic fuzzy sets

Intuitionistic fuzzy sets are a generalization of the ordinary fuzzy sets in which we have both a membership function μ and a nonmembership function ν. In this article we consider the problem of defining a correlation coefficient between two intuitionistic fuzzy sets. We show that by interpreting an intuitionistic fuzzy set as an ensemble of ordinary fuzzy sets we are able to derive a simple, intuitively satisfying correlation coefficient between two intuitionistic fuzzy sets. We show the reasonableness of the results obtained by examining several test cases. © 2004 Wiley Periodicals, Inc.     

A comparative evaluation of dental luting cements by fracture toughness tests and fractography

In recent years there has been a shift from traditional methods of investigating dental materials to a fracture mechanics approach. Fracture toughness (KIC) is an intrinsic material property which can be considered to be a measure of a material's resistance to crack propagation. Glass-ionomer cements are biocompatible and bioactive dental restorative materials, but they suffer from poor fracture toughness and are extremely susceptible to dehydration. The main objective of this study was to evaluate the fracture toughness of three types of commercially available dental cements (polyacid-modified composite resin, resin-modified and conventional glass ionomer) using a short-rod chevron-notch test and to investigate and interpret the results by means of fractography using scanning electron microscopy. Ten specimens of each cement were fabricated according to manufacturers' instructions, coated in varnish, and stored at ambient laboratory humidity, 100 per cent relative humidity, or in water at 37 degrees C for 7 days prior to preparation for testing. Results indicated that significant differences existed between each group of materials and that the fracture toughness ranged from 0.27 to 0.72 MN/m3/2. It was concluded that the resin-modified glass-ionomer cement demonstrated the highest resistance to crack propagation. Fractographs clearly showed areas of stable and unstable crack growth along the fractured surfaces for the three materials examined.     

The Effect of Drying Temperature on Physical Properties of Thin Gelatin Films

The molecular morphology of thin gelatin films, controlled through the casting temperature, was monitored by wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). Gelatin films dried at lower temperatures had a markedly higher crystalline or helical structure with a slightly higher T_g and lower ΔC_p compared with hot dried films, which had a more coiled structure. The relationship between molecular morphology and gelatin-water interaction in terms of hydration behavior and water diffusivity was assessed using dynamic vapor sorption (DVS). The sorption capacity increased and the level of hysteresis decreased with increasing the degree of crystallinity. The difference in the aging behavior of the films was explained in terms of the difference between the glass transition and aging temperatures, (Tg – Ta).     

Treatment with a nonsteroidal antiinflammatory drug after calving did not improve milk production,health, or reproduction parameters in pasture-grazed dairy cows

Previous research results have indicated an increase in pregnancy rate in pasture-grazed cows treated with a nonsteroidal antiinflammatory drug (NSAID) 3 to 4 wk postcalving, when a high proportion of nucleated cells from within the uterus were polymorphonucleated; however, no effect on milk production was detected. It was hypothesized that this lack of effect on milk production was because the administration of the NSAID was too late after calving. The aims of the current study were to evaluate the timing of administering a propionic acid-derived NSAID (i.e., carprofen) on milk production, metabolic status, uterine health, and reproductive performance. Six-hundred and thirty-nine cows (134 primiparous and 505 multiparous) calving between July 4 and September 5, 2012, in 2 herds (herd 1: n = 228; herd 2: n = 411) were enrolled. Using a randomized block design, cows were allocated to 1 of 3 treatment groups as they calved: (1) no treatment (control; n = 221), (2) NSAID administered on d 1, 3, and 5 postcalving (early; n = 214), and (3) NSAID administered on d 19, 21, and 23 postcalving (late; n = 204). Milk production and composition, and body condition were determined weekly. Blood was sampled at 4 time points (1 precalving and 3 postcalving) to determine the effects of treatment on indicators of metabolic health and energy status. Uterine health was determined by measuring the proportion of nucleated cells that were polymorphonucleated following cytobrush sampling of the uterus between d 13 to 24 and d 30 to 49 postcalving. Irrespective of timing of application, NSAID did not affect milk production, body weight, or body condition during early lactation. Treatment with an NSAID 19 to 23 d postcalving increased the proportion of cows submitted for breeding during the first 3 wk of the seasonal breeding program (control: 85%, early: 83%, and late: 92%), but did not affect conception or pregnancy rates. No detectable effect of treatment on uterine health or circulating metabolites and minerals existed, although cows in the early NSAID treatment group had marginally lower serum β-hydroxybutyrate concentrations (0.1 mmol/L) than the other groups between 2 and 26 d in milk. In conclusion, administration of this particular NSAID at either 1 or 3 wk after calving did not improve milk production, indicators of health, or reproductive performance.     

Partially Hydrolyzed Soy Protein Shows Enhanced Transport of Amino Acids Compared to Nonhydrolyzed Protein across an Intestinal Epithelial Cell Monolayer

Consumption of protein hydrolysates has been proposed to stimulate muscle anabolism more than intact (nonhydrolyzed) proteins via accelerated delivery of amino acids for muscle protein synthesis (MPS). We evaluated whether the rate of amino acid uptake and transport across intestinal cells was enhanced for soy protein hydrolysates versus nonhydrolyzed soy protein. Intact and partially hydrolyzed proteins were subject to simulated gut digestion and applied to the apical surface of Caco‐2 monolayers. Basolateral media was harvested after 3 h and quantitatively analyzed for free amino acids using ion‐exchange chromatography and comparison to an included reference standard. Basolateral concentrations of all amino acids were higher (mean 32%) for hydrolyzed versus nonhydrolyzed protein with the greatest differences in histidine, lysine, and valine. Scale‐up production of the soy protein hydrolysate did not diminish its enhanced absorption properties. These data support the hypothesis that hydrolyzed soy protein may provide dietary amino acids that are more rapidly transported across the intestinal epithelium versus intact soy protein. This would be important under conditions where rapid and increased levels of amino acids are needed such as in the stimulation of MPS.