Stress Analysis of a Stepped-Lap Bonded Repair Joint in Composite Laminate under Compressive Loading

With increasing the usage of advanced composite materials in aircraft structures, it is required to have a suitable repair technology for composite airframe. One of the primary requisites of the repair in such structures is that the repaired surface should not affect the aerodynamic contour. Adhesively bonded repair joints are generally preferred over mechanically fastened repair joints to avoid the stress concentration and achieve smooth aerodynamic surface. Significant numbers of research works have been carried on interface stress distributions for lap, butt and scarf adhesive repaired joints under the static tensile loading. However, the behavior of stepped-lap adhesive joints under compressive loading has not been fully understood and there are not many literatures available on this subject. The present work focuses on stress analysis of a laminate that is repaired through a stepped-lap joint repair scheme. The stress analysis has been carried out and stress distributions in the laminate, patch and adhesive were studied. In order to establish and validate the FE approach for analysis of stepped-lap repair joint subjected to compression, an experimental study also has been carried out. The strains from the analysis have been compared with the strains obtained from the test at important locations. Both the results have shown good agreement

Effect of Muons on the Phase Transition in Magnetised Proto-Neutron Star Matter

We study the effect of inclusion of muons and the muon neutrinos on the phase transition from nuclear to quark matter in a magnetised proto-neutron star and compare our results with those obtained by us without the muons. We find that the inclusion of muons changes slightly the nuclear density at which transition occurs.However the dependence of this transition density on various chemical potentials, temperature and the magnetic field remains quantitatively the same.Comment: LaTex2e file with four postscript figure

Effect of plant and animal protein sources on the growth, gonadal maturity and proximate composition of Labeo rohita (Hamilton, 1822)

The aim of the present study was to evaluate the effect of plant and animal sources in the diet of Labeo rohita with an overall goal of gaining sustainable fish and egg production. Fishes with an initial weight of 310-323 g were fed with five different isocaloric (3Kcalg-1) diets viz. D1 ( control diet- 30% rice bran + 70% groundnut meal), D2 (30% rice bran + 50% groundnut meal + 20% fish meal), D3 (30% rice bran + 50% groundnut meal + 20% mustard meal), D4 (30% rice bran + 30% groundnut meal + 20% mustard meal + 20 % fish meal) and D5 (30% rice bran + 30% soybean meal + 20% mustard meal + 20 % fish meal) @ 3% of fish biomass for 270 days. Significantly higher weight gain and better gonadal maturity was recorded in fishes fed with diet containing fish meal than other. Among diets containing fish meal (D2, D4, D5), fish fed on diet D2 resulted in higher somatic growth (35.67, 42.80, 28.10 and 18.48% higher net weight gain than D1, D3, D4 and D5, respectively) and better gonadal development (43.20, 50.08, 22.59 and 23.25% higher absolute fecundity than D1, D3, D4 and D5,respectively) in L. rohita. Hence, Our study revealed that for higher growth and better broodstock development, L. rohita may be fed on diet formulated with 30% rice bran, 50% groundnut meal and 20% fish meal

Effects of Cyanobacterial Lipopolysaccharides from Microcystis on Glutathione-Based Detoxification Pathways in the Zebrafish (Danio rerio) Embryo

Cyanobacteria (“blue-green algae”) are recognized producers of a diverse array of toxic secondary metabolites. Of these, the lipopolysaccharides (LPS), produced by all cyanobacteria, remain to be well investigated. In the current study, we specifically employed the zebrafish (Danio rerio) embryo to investigate the effects of LPS from geographically diverse strains of the widespread cyanobacterial genus, Microcystis, on several detoxifying enzymes/pathways, including glutathione-S-transferase (GST), glutathione peroxidase (GPx)/glutathione reductase (GR), superoxide dismutase (SOD), and catalase (CAT), and compared observed effects to those of heterotrophic bacterial (i.e., E. coli) LPS. In agreement with previous studies, cyanobacterial LPS significantly reduced GST in embryos exposed to LPS in all treatments. In contrast, GPx moderately increased in embryos exposed to LPS, with no effect on reciprocal GR activity. Interestingly, total glutathione levels were elevated in embryos exposed to Microcystis LPS, but the relative levels of reduced and oxidized glutathione (i.e., GSH/GSSG) were, likewise, elevated suggesting that oxidative stress is not involved in the observed effects as typical of heterotrophic bacterial LPS in mammalian systems. In further support of this, no effect was observed with respect to CAT or SOD activity. These findings demonstrate that Microcystis LPS affects glutathione-based detoxification pathways in the zebrafish embryo, and more generally, that this model is well suited for investigating the apparent toxicophore of cyanobacterial LPS, including possible differences in structure-activity relationships between heterotrophic and cyanobacterial LPS, and teleost fish versus mammalian systems

Oil Spill Occurrences along Indian Exclusive Economic Zone

Oil Spill Occurrences along Indian Exclusive Economic Zon

The microbiology of impetigo in Indigenous children: associations between Streptococcus pyogenes, Staphylococcus aureus, scabies, and nasal carriage

BackgroundImpetigo is caused by both Streptococcus pyogenes and Staphylococcus aureus; the relative contributions of each have been reported to fluctuate with time and region. While S. aureus is reportedly on the increase in most industrialised settings, S. pyogenes is still thought to drive impetigo in endemic, tropical regions. However, few studies have utilised high quality microbiological culture methods to confirm this assumption. We report the prevalence and antimicrobial resistance of impetigo pathogens recovered in a randomised, controlled trial of impetigo treatment conducted in remote Indigenous communities of northern Australia.MethodsEach child had one or two sores, and the anterior nares, swabbed. All swabs were transported in skim milk tryptone glucose glycogen broth and frozen at –70°C, until plated on horse blood agar. S. aureus and S. pyogenes were confirmed with latex agglutination.ResultsFrom 508 children, we collected 872 swabs of sores and 504 swabs from the anterior nares prior to commencement of antibiotic therapy. S. pyogenes and S. aureus were identified together in 503/872 (58%) of sores; with an additional 207/872 (24%) sores having S. pyogenes and 81/872 (9%) S. aureus, in isolation. Skin sore swabs taken during episodes with a concurrent diagnosis of scabies were more likely to culture S. pyogenes (OR 2.2, 95% CI 1.1 – 4.4, p = 0.03). Eighteen percent of children had nasal carriage of skin pathogens. There was no association between the presence of S. aureus in the nose and skin. Methicillin-resistance was detected in 15% of children who cultured S. aureus from either a sore or their nose. There was no association found between the severity of impetigo and the detection of a skin pathogen.ConclusionsS. pyogenes remains the principal pathogen in tropical impetigo; the relatively high contribution of S. aureus as a co-pathogen has also been confirmed. Children with scabies were more likely to have S. pyogenes detected. While clearance of S. pyogenes is the key determinant of treatment efficacy, co-infection with S. aureus warrants consideration of treatment options that are effective against both pathogens where impetigo is severe and prevalent

Prenatal factors contribute to the emergence of kwoshiorkor or marasmus in severe undernutrition: evidence for the predictive adaptation model

Severe acute malnutrition in childhood manifests as oedematous (kwashiorkor, marasmic kwashiorkor) and non-oedematous (marasmus) syndromes with very different prognoses. Kwashiorkor differs from marasmus in the patterns of protein, amino acid and lipid metabolism when patients are acutely ill as well as after rehabilitation to ideal weight for height. Metabolic patterns among marasmic patients define them as metabolically thrifty, while kwashiorkor patients function as metabolically profligate. Such differences might underlie syndromic presentation and prognosis. However, no fundamental explanation exists for these differences in metabolism, nor clinical pictures, given similar exposures to undernutrition. We hypothesized that different developmental trajectories underlie these clinical-metabolic phenotypes: if so this would be strong evidence in support of predictive adaptation model of developmental plasticity