Statistical Methods For Agricultural Workers

(1976). Nuclear Tracks in Solids (Principles and Applications) Nuclear Technology: Vol. 30, No. 1, pp. 91-92.

Nuclear Tracks in Solids (Principles and Applications)

Induction generators are increasingly being used in nonconventional energy systems such as wind, micro/mini hydro, etc. The advantages of using an induction generator instead of a synchronous generator are well known. Some of them are reduced unit cost and size, ruggedness, brushless (in squirrel cage construction), absence of separate dc source, ease of maintenance, self-protection against severe overloads and short circuits, etc. In isolated systems, squirrel cage induction generators with capacitor excitation, known as self-excited induction generators (SEIGs), are very popular. This paper presents an exhaustive survey of the literature over the past 25 years discussing the process of self-excitation and voltage buildup, modeling, steady-state, and transient analysis, reactive power control methods, and parallel operation of SEIG.

Three-phase self-excited induction generators: an overview

Glutathione and glutathione reductase: a boon in disguise for plant abiotic stress defense operations

An analytical technique using the `Newton-Raphson' method is presented to identify the saturated magnetising reactance and the generated frequency of a self-excited induction generator for a given capacitance, speed and load. The technique is shown to be very efficient in analysing such systems under steady state. Computed results are compared with the experimentally obtained values on a laboratory machine, and a reasonable correlation has been observed. Effects of various system parameters on the steady-state performance have been studied, and the results presented provide guidelines for optimum design of such systems.

Analysis of self-excited induction generators

The paper presents the performance characteristics of different induction machines of various ratings operating as a capacitor self-excited induction generator. Their computed performance is compared with commercially designed line excited induction generators operating as self excited induction generators. An algorithm, using the Newton-Raphson method and steady state equivalent circuit for the machine, is developed to compute the excitation requirement for maintaining a constant terminal voltage at different loads. This technique is also used to compute the number of capacitor steps required to load the machine, from no load to full load, while maintaining terminal voltage within specified limits. The optimum output power of the machine is computed without exceeding the rated stator current for its rated speed. The voltage range within which the machine is expected to operate at or above its rated capacity in stand alone mode, but without being overloaded, is also obtained. The effect of speed on excitation requirements is studied.

Comparative study on the performance of a commercially designed induction generator with induction motors operating as self excited induction generators

Uranium analysis of geological samples, water and plants from Kulu Area, Himachal Pradesh, India

A new technique to compute the performance of self excited cage induction generator (SEIG) is presented. The proposed method for the analysis of SEIG is capable to provide the performance of SEIG in all the steady state operating conditions. The analysis of self excited cage induction generator problem is formulated as multivariable unconstrained nonlinear optimization problem. The impedance of equivalent circuit of the induction machine is taken as an objective function. The frequency and magnetising reactance or frequency and capacitive reactance, are selected as the independent variables depending upon operating conditions of the machine. The variables are allowed to vary only within their known upper and lower practical limits during the optimization process so as to achieve practically acceptable value of these variables. The optimization problem is solved using Rosenbrock's method of rotating coordinates. The developed mathematical model is quite general in nature and can be implemented for...

A new technique for the analysis of self excited induction generator

Sulfur (S) is an essential element for growth and physiological functioning of plants. S uptake and assimilation in higher plants are crucial factors determining crop yield, quality, and even resistance to various biotic and abiotic stresses. The sulfur assimilation pathway, which leads to cysteine (Cys) biosynthesis, involves highand low-affinity sulfate transporters and several enzymes. The biochemical and genetic regulation of these pathways is affected by oxidative stress, sulfur deficiency, and heavy metal exposure. In fact thiols are the main form of reduced sulfur in plants to cope with heavy metal stress through enhanced synthesis of heavy metal chelating molecules, glutathione, and phytochelatins (PCs). Cadmium is the most potent activator of phytochelatins (PCs). The present chapter summarizes the available data and information on various aspects and control of enzymatic and nonenzymatic pathways in relation to sulfate assimilation-reduction and metabolism of organic reduced S-containing compounds when plants are challenged by cadmium.

Sulfur Assimilation and Cadmium Tolerance in Plants

. The present research is aimed at accessing the relationship between variation in the soil gases radon (222Rn) and helium (4He) and recently developed fissures and other neotectonic features in Nurpur and Nadha areas of the NW Himalayas, India. Two soil-gas surveys were conducted on/near known faults to reconfirm their position using soil gas technique and to check their present activity. During these surveys, soil-gas samples were collected along traverses crossing the observed structures. The data analysis reveals that the concentrations of radon and helium along the Dehar lineament and the longitudinal profile (Profile D) are very high compared to any other thrust/lineament of the Nurpur area. The Nadha area shows high values of radon and helium concentrations along/near the Himalayan Frontal Fault (HFF) as compared to the adjoining areas. This indicates the presence of some buried fault/fault zone running parallel to the HFF, not exposed to the surface and not delineated by satellite data but is geochemically active and might be tectonically active too. Hence, soil helium and radon gas patterns have been combined with morphological and geological observations to supply useful constraints for deformation of tectonic environments.

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S. Singh

Papers

Comparative study on the performance of a commercially designed induction generator with induction motors operating as self excited induction generators

Uranium analysis of geological samples, water and plants from Kulu Area, Himachal Pradesh, India

A new technique for the analysis of self excited induction generator

Sulfur Assimilation and Cadmium Tolerance in Plants

Soil-gas radon/helium surveys in some neotectonic areas of NW Himalayan foothills, India