A general theory for the identification of criteria within which an enzymic reaction can exhibit multiplicity (i.e. multiple steady states) is reviewed. Application of the theory to four types of kinetic models encountered in biochemical reactions is illustrated and figures are presented to delineate the region of multiplicity. The stability of the steady states is analysed for small perturbation about the steady state. 相似文献
An adjustable-speed drive comprising a slip-ring induction motor and a cycloconverter-type thyristor-commutator in its rotor circuit has been developed. The thyristor-commutator acts as a frequency-changer like a conventional commutator in a stator-fed ac commutator motor, converting line-frequency injected voltages directly to slip-frequency at the rotor terminals. The circuit permits a reversible power flow naturally, and speed-control is possible for subsynchronous as well as supersynchronous operation by controlling the injected secondary voltage. A rotor position-detector is used to switch the thyristor configuration in a sequential manner to generate an output voltage having a predominant slip-frequency component. The control logic and triggering circuit developed for the experimental drive are described in some detail. Experimental results as obtained with a laboratory model are presented together with some results of computer simulation of the drive system. Major limitations of the scheme and the scope for improvement are discussed. 相似文献
In this article, we develop two-stage, three-stage, and accelerated sequential procedures for the point estimation of the mean μ of an inverse Gaussian distribution when the scale parameter λ is unknown. Both minimum risk and bounded risk estimation problems are considered subject to a weighted squared error loss function. We aim at controlling the associated risk functions for all three procedures. Second-order approximations are obtained for the proposed procedures. 相似文献
The present paper investigates the impact of three radiation patterns of LED namely Lambertian, Batwing, Elliptical on the BER performance of 4 × 4 indoor multiple-input multiple-output (MIMO) visible light communication (VLC) system. The BER simulation has been done using LOS and LOS plus first reflection (L-R1) signals for ceiling-mounted and wall-mounted LEDs. For the case of ceiling-mounted LEDs, impulse response and BER have been computed using those radiation patterns at the centre and corner of a room (5 m × 5 m × 3 m). It has been found that LED having Elliptical radiation profile is more suitable for LOS signal when receiver is placed at the centre position whereas, Batwing radiation is suitable for L-R1 signal, both at the centre and corner positions. In the case of wall-mounted LEDs, impulse response and BER have been determined at the centre of the room using LOS and L-R1 signals. The results show that Batwing has least BER using LOS signal due to its wide radiation beam, but for L-R1 signal, the Elliptical profile having its narrow radiation beam has provided better BER performance. The present study shows that the BER in MIMO-VLC system not only depends on the transmitter and receiver position but also on the radiation patterns of LED and higher order reflection signals.
Climate change causes environmental depletion, with threats to the global economy. The health and productivity of ecosystems underpin agriculture, with stable ecosystems being the foundation for economic livelihoods and food security. This study proposes adaptation measures, using geospatial technology, for conserving natural resources and improving livelihoods of the local community from climate change scenarios. Planning, policy decisions and resultant programmes are required for natural resource management, which must be based on broad citizen participation and the engagement of rural communities. The suggested adaptation measures will help the planning system to regulate development of natural resources and the socio‐economic environment. The major natural resources in the environment are land and water, both of which can be severely degraded by human interventions, as well as climate change. Various thematic maps are prepared with the use of geospatial technology, in order to be helpful for site‐suitability analysis directed to the preparation of land and water management action plans for socio‐economic development. The study area is a micro‐watershed of the catchment of Ansupa Lake in the Cuttack District of Odisha, India. To reduce climate change impacts on natural resources and economic livelihoods, some adaptation measures have been proposed (e.g., 68.9 ha for afforestation.; 13.94 ha for gap plantations and agro‐horticulture; 389.62 ha for farm ponds and renovation of existing ponds for pisciculture and duckery activities, etc.; 11.33 ha for land management, along with five bore wells, eight dug wells, 51 LBS/check dams, and four WHSs, etc., for water management for sustainable use). 相似文献
Sustainable and cost‐effective energy generation has become crucial for fulfilling present energy requirements. For this purpose, the development of cheap, scalable, efficient, and reliable catalysts is essential. Carbon‐based heteroatom‐doped, 3D, and mesoporous electrodes are very promising as catalysts for electrochemical energy conversion and storage. Various carbon allotropes doped with a variety of heteroatoms can be utilized for cost‐effective mass production of electrode materials. 3D porous carbon electrodes provide multiple advantages, such as large surface area, maximized exposure to active sites, 3D conductive pathways for efficient electron transport, and porous channels to facilitate electrolyte diffusion. However, it is challenging to synthesize and functionalize isotropic 3D carbon structures. Here, various synthesis processes of 3D porous carbon materials are summarized to understand how their physical and chemical properties together with heteroatom doping dictate the electrochemical catalytic performance. Prospects of attractive 3D carbon structural materials for energy conversion and efficient integrated energy systems are also discussed. 相似文献