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991.
Narendra Reddy 《Polymer》2005,46(15):5494-5500
We have developed a fiber extraction method that produces fibers from cornstalks with mechanical properties similar to that of the common textile fibers. The fiber extraction method developed results in partial delignification and produces fibers from cornstalks that are suitable for textile and other industrial applications. The structure of the fibers obtained was investigated using X-ray diffraction and scanning electron microscope. The structure and composition of the natural cellulose fibers obtained from cornstalks are different than that of the common bast fibers such as flax and kenaf. Tensile properties of the fibers were studied using an Instron tensile tester. This study found that cornstalk fibers have relatively lower percent crystallinity but similar microfibrillar angle as that of the common bast fibers. The structure and properties of cornstalk fibers indicate that the fibers are suitable for producing various textile products. 相似文献
992.
Matt Poulsen Stephen Ducharme A. V. Sorokin Sahadeva Reddy James M. Takacs Y. Wen Jihee Kim S. Adenwalla 《Ferroelectrics Letters Section》2005,32(3):91-97
The ferroelectric and piezoelectric properties of newly synthesized polymer systems have been studied. To date PVDF and its copolymers P(VDF-TrFE) have provided the bulk of the knowledge pertaining to ferroelectricity in polymers. Recently, ultrathin ferroelectric films of P(VDF-TrFE) 70:30 have been fabricated using the Langmuir-Blodgett technique [4]. In this study, various new polymers have been synthesized by chemically altering the PVDF structure. This alteration was performed in order to enhance the amphiphilic nature of the polymer and thus improve the LB film quality and control. Various chemical groups have been used to replace the electropositive hydrogen and electronegative fluorine found in the traditional PVDF chemical structure, including Nitrile, Ester, and Methyl groups. In all cases the resulting chemical structure provides for a net dipole moment directed from the electronegative side of the monomer to the electropositive side. However, to obtain ferroelectricity these microscopic dipoles must first pack in a manner such that a reversible macroscopic dipole is obtained. Both structural and dielectric studies have been performed on a number of newly synthesized systems. The structural properties of these new materials were probed using both temperature-dependent x-ray diffraction and differential scanning calorimetry, while dielectric properties were investigated using electric field and temperature-dependent capacitance and polarization measurements. 相似文献
993.
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. 相似文献
994.
E. Sagar N. Pavan Kumar D.C. Krishna P. Venugopal Reddy 《Journal of Superconductivity and Novel Magnetism》2014,27(9):2067-2072
Colossal magnetoresistive (CMR) materials with the compositional formula, Nd0.67A0.33MnO3 (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. 相似文献
995.
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. 相似文献
996.
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 相似文献
997.
Anirban Guha Debashree Sengupta Attipalli Ramachandra Reddy 《Journal of the science of food and agriculture》2010,90(15):2649-2659
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 (Tl), higher internal/ambient CO2 ratios (Ci/Ca), greater stomatal conductance to CO2 (gs) and stability in photosystem II efficiency were associated with better net photosynthetic rates (Pn) 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 相似文献
998.
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. 相似文献
999.
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. 相似文献
1000.
G
V Ramana Reddy A Muthulakshmi C Dulcy Evangelin P Rajendran 《Polymer International》2001,50(3):354-359
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, Eoverall, 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 相似文献