Advanced Ultrasonic Inspection of Thick-Section Composite Structures for In-Field Asset Maintenance.

An investigation into the inspection capabilities of in-field advanced ultrasound detection for use on ultra-thick (20 to 100 mm) glass fibre-reinforced polyester composites is presented. Plates were manufactured using custom moulding techniques, such that delamination flaws were created at calibrated depths. The full matrix capture technique with an on-board total focussing method was used to detect flaws scanned by a 0.5 MHz linear array probe. Flaw through-thickness dimensions were altered to assess the threshold for crack face separation at which delaminations could be identified. Furthermore, part thickness and in-plane flaw dimensions were varied to identify the inspection capability limitations of advanced ultrasonics for thick composites. The results presented in this study demonstrate an inverse relationship between the ability to find delaminations and plate thicknesses, with inspections successful at depths up to 74 mm. When the delamination thickness exhibited surface-to-surface contact, the inspection capability was reduced to 35 mm. There was an exponential decay relationship between the accuracy of the flaw depth measurement and plate thickness, likely due to the necessity of low probe frequencies. The effective inspection depth was determined to be in the range of 1 to 20 times the wavelength. It is speculated that the accuracy of measurements could be improved using probes with novel coupling solutions, and detectors with optimised signal processing/filtration algorithms.

Experimental Study on the Interlaminar Fracture Properties of Carbon Fibre Reinforced Polymer Composites with a Single Embedded Toughened Film.

In this study, two types of single polymer films have been inserted in a composite laminate to examine their toughening effects on mechanical properties. The first is a thermoplastic polyurethane (PU) film, and the second is an adhesive epoxy film featuring a polyester net. The laminates were manufactured either using a co-curing (CC) process or a secondary bonding (SB) process used for the epoxy film. Mode I and mode II interlaminar fracture toughness were measured for laminates manufactured by both processes and compared with the corresponding reference laminate toughness. A significant increase in both mode I and mode II toughness resulted when introducing a single PU film, approximately 290% and 50%, respectively. Similarly, the epoxy film improved the interlaminar fracture properties; the CC process produced an increase of 175% for mode II toughness, while the SB adhesive film showed an increase of 75% for mode II toughness.

Supporting a Healthy Microbiome for the Primary Prevention of Eczema.

Eczema is increasing worldwide with associated increases in health costs and decreases in quality of life. There are many factors that are speculated to interact in the development of eczema including genetics and environmental exposures. Prevention of the development of eczema may prevent the further development of food allergies and asthma. This concept has prompted a variety of research into the area of primary prevention of eczema in infants. This exploration includes a growing body of research examining infants supplemented with probiotics, prebiotics, or both (synbiotics) often compared with their breastfed counterparts. The goal of this paper is to examine the evidence for manipulating the microbiome in the prevention of eczema. Several strains of probiotics, compositions of prebiotics, and varied combinations of both are commercially available. Evidence supports altering the microbiome in infants at high risk of atopy who are not able to breastfeed with Lactobacillus strains when given both prenatally followed by prolonged use (greater than 6 months) postnatally for the primary prevention of eczema. Prebiotics have also been shown beneficial for primary prevention of eczema in formula-fed infants with prolonged use greater than 6 months. These findings are in keeping with the World Allergy Organization (WAO) recommendations that support interventions to manipulate the microbiome with both probiotics and prebiotics.

Fruit maturation patterns of Carya spp. (Juglandaceae): an intra-crown analysis of growth and reproduction.

Fruit survival patterns, from fertilization to maturation, were examined for Carya ovata and C. tomentosa in a New Jersey USA forest. We observed fruiting and shoot growth characteristics over a 3-yr period to determine: (1) the patterns of fruit survivorship (from initiation to maturity) within and among years, (2) the relationships between shoot growth, fruit initiation, and fruit survival to maturity, and (3) the influence of phytophagous insects on fruit survival. We found that within years, smaller infructescences (1-2 fruits) exhibited greater relative survivorship than larger ones (3-4 fruits); however, absolute nut production was greatest for mid-sized infructescences (2-3 fruits). Among years, fruit survivorship varied considerably within populations. Across the 3-yr period we observed average fruit survivorship to be convex, linear, and concave, respectively. Likewise, shoot characteristics (length, width, number of leaves) varied concomitantly (decreasing fruit survivorship was accompanied by decreasing shoot length and number of leaves). Within years, we found no strong relationship between shoot characteristics and infructescence size and survival. The patterns of tree-to-tree variation suggested a strong genetic basis to shoot growth and fruit maturation. However, patterns of variation within and among years also indicated a strong environmental influence on these traits as well. Natural phytophagy by insects was observed to be low (<5%); however, shoot defoliations of 10-25% were not uncommon. Experimental defoliations (ambient, 10-15%, 20-40%, and 75-100%) did not result in reduced survival to maturity. Collectively, the data suggest that year-to-year variability in shoot growth has a greater influence on fruit maturation patterns than within year fruit-shoot relations.

REPRODUCTIVE ECOLOGY OF CARYA (JUGLANDACEAE): PHENOLOGY, POLLINATION, AND BREEDING SYSTEM OF TWO SYMPATRIC TREE SPECIES.

Observations and experiments on both shagbark (Carya ovata; 2n = 32) and mockernut (C. tomentosa; 2n = 64) hickories in a New Jersey forest were performed over a 2-year period to determine the mechanisms operating both to maintain reproductive fidelity and to regulate fruit initiation. Phenological observations indicated significant differences between the species for almost all vegetative and reproductive characters examined; however, a large amount of overlap was also observed. Pollination experiments indicated that pollen limitation is not a significant factor in reducing fruit set in these anemophilous species. Pollen-ovule ratios ranged from 1 to 25 × 106 . Pollen was 80-90% viable at time of shedding. The large surface area of vegetative structures (e.g., leaves) at the time of pollination may retard the flow of pollen into and out of the canopy and thus increase self-pollination. A full diallel cross, replicated 5 times, was made among 8 trees (4 trees of each species) to characterize combining ability and compatibility relationships. All trees were found to be both geitonogamous and xenogamous to varying degrees. A high frequency of putative interploidal cross-compatibility was also observed. Fruits from these interspecific crosses were found to be germinable. Observations on individual trees suggested that dichogamy may help to reduce selfing and promote outcrossing in this breeding system. While most trees exhibited a temporal separation of genders, the trait was found to be quite plastic (i.e., trees switched between protogyny and protandry between years). Pistillate flowers were receptive for all trees within a species during the same general time period; however, pollen shedding varied considerably among trees and between years. Both species appear to be utilizing a broad array of mechanisms in order to maintain reproductive fidelity and adequate fruit set.