Simulation of Construction of Cable-Stayed Bridges

Construction of cable-stayed bridges involves major changes in configuration of the structure with the addition and removal of structural components to the partially constructed structure. At every stage of construction, it is necessary to have sufficient information about the existing partial structure as-built, to verify the requirements called for in the construction guidelines and to investigate the effects of possible modifications in the construction procedures. The final stresses and deformations in the completed structure are strongly dependent on the sequence of events during the construction and the erection procedure used. Therefore, analysis of the actual construction sequence is an important first step in any analysis of the performance of the bridge under external loads. In this paper a general methodology for construction sequence simulation of cable-stayed bridges is presented, and stage-by-stage construction of an actual bridge is simulated. The objective of the simulation is to evaluate short-term and long-term influences of the construction sequence on the structural integrity of the cable-stayed bridge. Comparisons are presented between results from the present analysis, conventional procedures, and the actual field measurements.     

Investigation of Magnetocaloric Behavior of Nanocrystalline Nd0.67A0.33MnO3, (A = Ca,Sr, Ba and Pb)

Colossal magnetoresistive (CMR) materials with the compositional formula, Nd_0.67A_0.33MnO₃ (where A = Ca, Sr, Ba, and Pb) in the nanocrystalline form were prepared by the PVA gel technique. After characterizing the samples structurally, a systematic investigation of magnetization has been undertaken, over a temperature range 10–300 K at 0.05 T magnetic field. An effort has been made to calculate the magnetocaloric behavior of all the samples theoretically using the experimental magnetization data. Other important parameters such as maximum entropy change, full width at half-maximum, relative cooling power, and maximum adiabatic temperature change under 0.05 T were also computed. The observed behavior has been explained qualitatively.     

Corrigendum to “Solution of economic dispatch problems by seeker optimization algorithm” by Binod Shaw et al. “Expert Systems with Applications”, 39 January (2012) 508–519

This paper presents a discussion of “Solution of economic dispatch problems by seeker optimization algorithm” by Binod Shaw et al. “Expert Systems with Applications”, 39 January (2012) 508–519. The discussed paper presented economic dispatch problem by experimenting with four example systems considering 20, 38, 40 and 10-unit test systems considering convex and nonconvex cost functions with and without transmission loss. However in the reported results, the total cost calculations are different for the given generation schedule. In this discussion, clarification regarding cost calculations is presented.     

Critical heat flux enhancement in pool boiling using alumina nanofluids

The pool boiling characteristics of dilute dispersions of alumina nanoparticles in water were studied. Consistent with other nanofluid studies, it was found that a significant enhancement in critical heat flux (CHF) can be achieved at modest nanoparticle concentrations (<0.1% by volume). During experimentation and subsequent inspection, formation of a porous layer of nanoparticles on the heater surface occurred during nucleate boiling. This layer significantly changes surface texture of the heater wire surface which could be the reason for improvement in the CHF value. © 2010 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20301     

Physiological optimality,allocation trade‐offs and antioxidant protection linked to better leaf yield performance in drought exposed mulberry

BACKGROUND: Mulberry (Morus spp. L.), usually linked to silkworm rearing, is now considered as a potential forage for livestock feeding and has great potential in world agriculture. Trait‐based investigations for leaf yield stability in mulberry under water stress have not been studied extensively. The present study aims to identify candidate traits conferring leaf yield stability in mulberry under drought. RESULTS: Four popular, indigenous mulberry cultivars (Morus indica L. cvs AR‐12, K‐2, M. Local and V‐1) were investigated. Low leaf temperature (T_l), higher internal/ambient CO₂ ratios (C_i/C_a), greater stomatal conductance to CO₂ (g_s) and stability in photosystem II efficiency were associated with better net photosynthetic rates (P_n) in V‐1, generating maximum leaf yield when compared to other drought‐exposed cultivars. Increased accumulation of foliar α‐tocopherol and ascorbic acid–glutathione pool, associated with higher carotenoids, proline and glycine betaine, facilitated lower lipid peroxidation and better leaf yield in V‐1 under drought. CONCLUSION: Minimal plasticity in photosynthetic gas exchange traits and better quantitative growth characteristics were attributed to leaf yield stability under drought. Lower photoinhibition, stabilized photochemistry, effective osmoregulation and enhanced activity of foliar antioxidants extensively contributed to drought tolerance and higher leaf yield in mulberry. Copyright © 2010 Society of Chemical Industry     

Equivalent Viscous Damping for a Bilinear Hysteretic Oscillator

A bilinear hysteretic model is commonly used to study elastoplastic structures. In this paper, a damped, bilinear hysteretic oscillator is studied under harmonic loading. We show the existence of an equivalent viscous damping for small values of a loading parameter such that the associated linear structure and the hysteretic structure have the same frequency response curves. We use the Kryloff-Bogoliuboff method of averaging to find the equivalent viscous damping as a function of the steady state amplitude. We present a model of a bilinear elastic oscillator which captures the steady-state dynamics of the hysteretic oscillator for low values of the loading parameter. We also study the nature of the dependence of the equivalent viscous damping on the kinematic hardening parameter.     

Sintering by recirculation of ferrogenous waste

Utilization of more plant wastes for production of quality sinters improves the productivity of the furnace at the same time plant wastes materials are recycled. The ferrogenous waste like dust catcher dust and gas cleaning plant sludge can be utilized in sintering for production of hot metal. Recycling of these iron bearing materials and flux materials have great economic importance in sintering as it is not only utilizing all iron generated byproducts but also the associated fuel rate reduction benefit for sintering process.     

Aqueous polymerization of ethyl acrylate initiated by ceric ion‐reducing agent systems in nitric acid medium

Kinetic study of aqueous polymerization of ethyl acrylate (EA) was carried out at 30 °C in dilute nitric acid medium by employing ammonium ceric nitrate (ACN)–methyl cellosolve (MC) and ACN–ethyl cellosolve (EC) as redox initiator systems. The ceric ion consumption was found to be first order with respect to ceric ion concentration with both initiator systems. The formation of complexes between Ce(IV) and reducing agents (RA) was observed. The order with respect to Ce(IV), reducing agents and monomer was evaluated for aqueous polymerization of EA by Ce(IV)–MC and Ce(IV)–EC redox initiator systems. The overall activation energy, E_overall, for aqueous polymerization of EA was evaluated in the temperature region of 27–40 °C with both initiator systems. A kinetic mechanism for aqueous polymerization of EA initiated by redox initiator systems is presented. © 2001 Society of Chemical Industry     

Structure and properties of cocoons and silk fibers produced by <Emphasis Type="Italic">Hyalophora cecropia</Emphasis>

This paper shows that silk fibers produced by cecropia (Hyalophora cecropia) have similar tensile properties but different amino acid composition than that of mulberry (Bombyx mori) silk. The cecropia fibers are also much finer and have better strength and modulus than tasar silk, the most common non-mulberry silk. Cecropia is one of the largest silk producing moths and has similar lifecycle to that of mulberry silk but is easier to grow and produces larger cocoons than mulberry silk. In this study, we have characterized the composition, morphology, physical and tensile properties, and thermal behavior of the cecropia silk. Cecropia cocoons have a three tier structure and are larger (750 mg) than the cocoons produced by B. mori (650 mg). Fibers in the three layers in cecropia cocoons have tensile properties similar to that of B. mori silk but are finer (1.7–2 denier) and have higher strength (3.8–4.3 g/denier) and modulus (68–92 g/denier) than tasar silk.