Modelling the fracture of cementitious materials

The crack band and the fictitious crack line models of the fracture process zone in cementitious materials are discussed. The two methods are quite similar. However, the fictitious crack model is shown to lend itself to a simple K-superposition method which makes use of known analytical expressions. This method is shown to give very similar results to a finite-element analysis of the fictitious crack model and has the advantage that it can be programmed for a personal computer. The predictive capability of the fictitious crack model is demonstrated by comparison of the experimental load-deflection curve for a small notch bend mortar specimen with a theoretical curve calculated from data obtained from larger beams. It is suggested that the RILEM test method for the determination of the fracture energy should be used also to establish a bilinear stress-displacement relationship for the strain-softening of the fracture process zone.     

Ongoing normal pregnancy after transfer of zona-free blastocysts: implications for embryo transfer in the human

Recent reports suggest that transfer of day 5 blastocysts improves implantation rates in in-vitro fertilization programmes. This paper reports a successful ongoing pregnancy after the transfer of zona-free day 6 expanded and hatching blastocysts. The patient was 37 years old and had undergone six stimulated and two thaw cycles previously, all of which had failed. Stimulation was by down-regulation and oocytes recovered transvaginally by ultrasound guidance. Two pronuclear embryos were co-cultured on Vero cells to day 6. The zonae of two hatching and two fully expanded blastocysts were removed using 0.5% pronase, and the zona-free blastocysts were then transferred. Pregnancy was confirmed on day 18 with a positive human chorionic gonadotrophin (HCG) and ultrasound at 6 weeks showed a single healthy fetal heart inside a clear sac. At 14 weeks a triple test (oestriol, J-HCG and alpha-fetoprotein) was normal and at 22 weeks a detailed ultrasound scan showed no congenital anomalies. This is the first report in the human of a normal ongoing pregnancy after the transfer of zona-free day 6 embryos.     

Selective binding and detection of magnetic labels using PHR sensor via photoresist micro-wells

We have developed a novel platform for selective binding of magnetic labels on planar Hall resistance sensor (PHR) for biosensing applications. The photoresist (PR) micro wells were prepared on the PHR sensor junctions to trap the magnetic bead at specified locations on the sensor surface and thin layer of Au was sputtered in the PR wells immobilize bimolecular. The Au surface is functionalized with single-stranded oligonucleotide and further biotin was used to immobilize streptavidin coated magnetic labels (Dynabeads Myone 1.0 microm, Invitrogen Co.). After removal of the PR wells on the sensor surface the non specific binding magnetic labels were successfully removed and only the chemically bounded magnetic labels were remained on the Au surface for detection of biomolecules using PHR sensor. We controlled the number of magnetic labels on the PHR sensor surface by using different sizes of the PR well on the junctions. The specifically bounded magnetic labels were successfully detected by characterizing the individual PHR sensor junctions. This technique enables the complete control over the magnetic labels for selective binding of biomolecules on the sensor surface for increasing the sensitivity of the PHR sensor as well as removal of the non specific bindings on the sensor surface.     

Combined Effect of Icing Medium and Red Alga <Emphasis Type="Italic">Gracilaria verrucosa</Emphasis> on Shelf Life Extension of Indian Mackerel (<Emphasis Type="Italic">Rastrelliger kanagurta</Emphasis>)

Flake ice refrigeration is a conventional but commonly employed technique to slow down fish spoilage and deterioration of nutritional values and sensory properties during chilled storage. In the present study, a methanolic extract of red alga Gracilaria verrucosa was characterised, and functional groups, such as alkenes, aldehydes, nitriles, galactans and galactose-4-sulphate were found. Subsequent identification of active compounds revealed the presence of potent preservative agents, such as butylated hydroxytoluene, sulfurous acid, 1,2-propanediol, benzeneacetic acid, cyclononasiloxane and tetracosamethyl-cyclododecasiloxane. The effect of incorporating G. verrucosa at two different concentrations (0.67 and 2.5 g lyophilised alga/L aqueous solution) in the icing medium was tested for the preservation of Indian mackerel (Rastrelliger kanagurta), compared to preservation in traditional ice prepared only from water. Microbial, chemical and sensory qualities were monitored in Indian mackerel chilled in ice with and without G. verrucosa during 15 days storage period. Inhibitory effects (p?<?0.05) on the microbial proliferation (mesophilic and psychrophilic bacteria) and chemical markers of fish deterioration (pH, TVB-N, TMA-N and biogenic amines) were evidenced for ice containing both concentrations of G. verrucosa, respectively, relative to the control medium. The sensory score acceptability limit reached 11 days for Indian mackerel stored in traditional ice and 15 days for Indian mackerel stored in ice with G. verrucosa extract. Thus, the icing medium containing G. verrucosa extract improves the quality and safety of Indian mackerel during storage and can be explored by the seafood industry as a biopreservative.     

Hybrid approach to implement multi-robotic navigation system using neural network,fuzzy logic,and bio-inspired optimization methodologies

Mobile robots have been increasingly popular in a variety of industries in recent years due to their ability to move in variable situations and perform routine jobs effectively. Path planning, without a dispute, performs a crucial part in multi-robot navigation, making it one of the very foremost investigated issues in robotics. In recent times, meta-heuristic strategies have been intensively investigated to tackle path planning issues in the similar way that optimizing issues were handled, or to design the optimal path for such multi-robotics to travel from the initial point to such goal. The fundamental purpose of portable multi-robot guidance is to navigate a mobile robot across a crowded area from initial point to target position while maintaining a safe route and creating optimum length for the path. Various strategies for robot navigational path planning were investigated by scientists in this field. This work seeks to discuss bio-inspired methods that are exploited to optimize hybrid neuro-fuzzy analysis which is the combination of neural network and fuzzy logic is optimized using the particle swarm optimization technique in real-time scenarios. Several optimization approaches of bio-inspired techniques are explained briefly. Its simulation findings, which are displayed for two simulated scenarios reveal that hybridization increases multi-robot navigation accuracy in terms of navigation duration and length of the path.     

Behavior of Aramid Fiber-Reinforced Polymer Reinforced High Strength Concrete Beams under Bending

Flexural test results of ten high strength concrete beams reinforced with aramid fiber-reinforced polymer (AFRP) bars together with a steel-reinforced beam that served as a reference are presented and discussed. All beams were tested under third-point loading. Test results have shown that a concrete beam, when reinforced with AFRP bars, becomes more flexible in the postcracking range than an equivalent steel-reinforced beam, demonstrates wider and predominantly vertical cracks even in the shear span, and may fail in an unusual flexure-shear mode. Major critical issues concerning flexural designs of AFRP-reinforced beams have been discussed in the perspective of code provisions, and suitable recommendations are made for practical design. A method has been suggested to provide a meaningful quantification of ductility for FRP-reinforced beams. Also the need for reducing the maximum spacing of stirrups from that specified in the current code provisions for sections subjected to large shear combined with significant bending moment has been identified and recommendations are made.     

Disinfestation techniques for major cereals: A status report

Management of stored product insects is a major concern and widely researched topic in the food and grain processing and storage industry. In the scenario of estimated utilization of produces exceeding the production, postharvest losses should be properly controlled to feed the growing population. The prevailing disinfestation techniques are forced to meet regulatory standards and market demands. The resistance developed by insects, environmental concerns, and occupational hazards lead to the vanishing of many chemicals used in insect and pest management programs. Some of the major disinfestation techniques such as the use of chemical fumigants, ozone, irradiation, dielectric heating, extreme temperature treatments, and bio rational approaches are discussed, particularly on the storage of cereal grains and its products, as they contribute to a significant proportion of food consumed worldwide. Newer techniques such as nonthermal plasma and metabolic stress disinfestation and decontamination for stored pest control are developed and evaluated in different parts of the world. The knowledge about the mode of action of these disinfestation techniques is important to avoid the cross‐resistance and multiple resistance developed by insects with frequently used techniques. Various alternatives to conventional fumigants are discussed in this review as there is a growing demand for toxic‐free, environment‐friendly, and, at the same time, efficient techniques.