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Background: Root knot nematode, Meloidogyne incognita is one of the main biotic constraints in reducing the quantity and quality of the cowpea crop in most of the growing areas of the world. The nematode produces galls on roots and disrupt the physiology of the plant by reducing crop yield and product quality and are therefore of great economic importance. Methods: Studies were conducted to estimate the yield loss of cowpea in field condition along with evaluation of few genotypes under net house condition against root knot nematode based on gall index, reaction response and number of egg masses/ 5 g of root at Directorate of Research, BCKV, West Bengal. Estimation of cowpea yield loss was conducted with the parameter of mean yield, percentage avoidable and increase in yield, Root Knot Index (RKI in 1-5 scale) and final nematode population reduction. Result: Under treated condition, cowpea yield was significantly increased ranging from 10.93 to 14.58% with 37.19 to 38.17% reduction of nematode population. The range of avoidable yield loss was 9.85 to 12.72%. In response reaction, 28 genotypes were found as moderately resistant. Local cowpea cultivar, Kashikanchan may be avoided at nematode infection area due to its high susceptibility and the moderately resistant genotypes may be suggested for the use in future breeding studies as a parental material to develop the root knot nematode resistant cultivars. [ABSTRACT FROM AUTHOR]

The electrical transport properties of hydroiodic acid doped polyaniline in the temperature range 77 ≤ T ≤ 300 K were studied. The magnetic field strength was varied to a maximum of 1T in the frequency range of 20 Hz-1 MHz. The ac conductivity followed the universal dielectric response σ (f) [proportional] [f.sup.s]. The trend in the variation of 's', the temperature dependence of the frequency exponent, indicated that correlated barrier hopping is the dominating charge transport mechanism. The ac conductivity also shows a positive variation with magnetic field, which can be interpreted by Maxwell-Wagner capacitor model. POLYM. ENG. SCI., 49:910-915, 2009. [C]2009 Society of Plastics Engineers, INTRODUCTION Conducting polymers have been extensively studied in the last few decades because of their significant application in applied and basic sciences. Pure polymers are basically insulators or non-crystalline semi [...]

Let f be a transcendental entire function defined in the open complex plane ℂ. A difference-monomial generated by f is an expression of the form F = fn(fm -1) ... (f (z+cj))..., where n, m and Vj are all non-negative integers. Now for the sake of definiteness let us take, Mi[f ] = fn(fm -1) ... (f (z+cj))..., where 1 ≤ i ≤ d. If M1 [f], M1 [f ],..., Mn [f] are such monomials in f as defined above, then ψ[f] = a1M1[f] + a2M2[f] + ... + anMn [f] where ai ≠ 0 (i = 1, 2,..., n) is called a difference-polynomial generated by f. In this paper, we compare the Valiron defect with the relative Nevan-linna defect of a particular type of differential-difference polynomial generated by a transcendental entire function with respect to integrated moduli of logarithmic derivative. Some examples are provided in order to justify the results obtained. [ABSTRACT FROM AUTHOR]

Operational transients involving large thermal shrinkage in the primary heat transport (PHT) volume of a pressurized heavy water reactor nuclear power plant may result in the undesirable lowering of PHT system pressure to a very low value. During some of the reactor trip incidents as reported from the operating units, the minimum PHT pressure obtained have lead to unwanted lineup of emergency core cooling system. A reduction of the dip in the PHT system pressure during such incidence can be achieved by increasing the net feed to the PHT volume, i.e., by increasing the holdup inventory in a fixed PHT boundary. Another option to maintain the PHT system pressure high during such transients is to keep the PHT temperature at a higher value. This can be achieved by removing less heat from the primary coolant. To reduce the heat transfer from the primary coolant to the secondary coolant in the steam generator (SG), the steam generator pressure controller (SGPC) set point has to be increased during such incidences. This will lead to a higher steam pressure and temperature in the SGs, thus reducing the temperature difference and heat transfer between primary and secondary coolant. Analysis has been carried out using the integrated system process dynamics analysis code. This code incorporates the mathematical models for the primary and secondary heat transport systems, these models are based on coupled solutions of unsteady state mass, momentum and energy conservation equations. The present paper deals with the details of the different mitigation schemes considered along with the results arrived at. Index Terms--PHWR, process dynamics, reactor trip, simulation, steam generator, thermalhydraullics.

The 500-MWe Indian pressurized heavy water (PHWR) incorporates many new features as compared to the earlier 220-MWe PHWRs. To evaluate the new design features like primary heat transport (PHT) system configuration with two loops, four primary circulating pumps (PCPs) and four passes through core, addition of a pressurizer (surge tank) in the PHT system along with a feed/bleed system and their safety-related implications, simulation model development and transient analyses are necessary. To mitigate the swell and shrinkage in the PHT system and to avoid high/low PHT system pressure during transients, a 30 [m.sup.3] pressurizer along with feed/bleed system is also included in the PHT pressure control system for the 500-MWe PHWR. At the same time, a reactor stepback is also actuated during the one PCP trip transient after tripping the corresponding (same side) PCP in the other loop. The corresponding PCP in the healthy loop is tripped to avoid unsymmetrical flow and pressure distribution in the two identical loops. A detailed transient analysis is required to study the individual contributions of various systems and provisions such as pressuriser, feed/bleed, and reactor step/set back in mitigating the consequences of the malfunction. Mathematical models for all the major components and sub-systems of the proposed 500-MWe PHWR were developed based on the conservation equations of mass, momentum, energy, and equation of state. Ali the associated control systems are also modeled. The PHT system includes the reactor core with nuclear fuel, PCP, PHT system pressure controller with feed/bleed system, and pressurizer (surge tank). The secondary system includes mainly the steam generators (SGs), the SG level, and pressure controllers, apart from the various steam-cycle components. All these models are integrated together to form the plant transient analysis computer code. Several transient studies have been carried out using this code to check the various design parameters and controller settings. The paper deals with the details of the mathematical model of PHT system and parametric study for one PCP trip transient analysis with set/step back. With the reactor setback option the temperature difference in the primary coolant across the SG tubes shows a high value, which may be misinterpreted (as a very high reactor power) by the reactor regulating system, leading to a reactor trip on high delta-T (across SG tubes) signal. To reduce the reactor power at a faster rate and to avoid the high delta-T signal, a stepback action is recommended during a single PCP trip incident based on transient analysis studies. Index Terms--Pressurized heavy water reactor (PHWR), process dynamics, pump trip, simulation, thermal hydraulics.