June 2011
·
23 Reads
·
2 Citations
Current Science
What is this page?
This page lists works of an author who doesn't have a ResearchGate profile or hasn't added the works to their profile yet. It is automatically generated from public (personal) data to further our legitimate goal of comprehensive and accurate scientific recordkeeping. If you are this author and want this page removed, please let us know.
Publications (163)
November 2010
·
20 Reads
Ground Water
October 2010
·
19 Reads
·
2 Citations
California's Santa Clara Valley, widely known as the Silicon Valley, manages its water resources admirably, integrating surface water, groundwater, artificial recharge, waste-water treatment, imported water, water conservation and public participation. As India seriously tackles its water challenges, the Silicon Valley's case history provides insights into how citizens of a hydrological basin may take control of their indigenous water resources based on an understanding of the essential attributes of hydrological systems, and drawing upon the best available science to achieve sustainable management. This case history also highlights the fact that even with the most sophisticated integrated water management, there are definite limits to the extent to which indigenous resources can satisfy water demands.
October 2010
·
10 Reads
Transport in Porous Media
Numerical models of diffusive transport, commonly considered as approximate solvers of the partial differential equation, focus on evaluation of gradients at a point. Gradient-approximation inaccuracies manifest themselves as errors in conductances and capacitances that enter into matrices that are finally solved. In turn, these errors arise from a lack of consideration of flow geometry in the point’s vicinity. In order to improve accuracy, flow geometry may be incorporated into evaluation of conductances and capacitances by choosing segments of flow tubes as volume elements. Flow tubes, inherent in the initial conditions, can be generated using appropriate interpolation schemes that are built into contouring algorithms. The principal task is to structure contouring tools in such a way as to generate information to facilitate accurate evaluation of conductances and capacitances. The logical framework of this novel approach is founded on the contributions of Maxwell, who visualized a flow domain as a collection of flow tubes, Ohm, who introduced the notion of resistance of a finite body, and Fick, who introduced a differential equation for diffusive flow through a tube of non-uniform cross section. Computer-graphics capability to implement this approach has become available only over the past two decades. Casting aside the notion of a point, the new paradigm is to evaluate flow-resistance over finite distances. The method suggested is referred to as a Resistance-Integral Natural-Coordinate Method (RINC). Formulated from first principles, this method dispenses with the differential equation as an intermediary to formulate the numerical equations. It proceeds directly from the physical problem to its numerical representation. KeywordsNumerical method-Natural-coordinates-Grid generator-Mesh generator-Integral methods
September 2010
·
21 Reads
Science
In his Editorial “Irreverence and Indian science” (30 April, p. [547][1]), R. A. Mashelkar observes that Indian science lacks adventure and a spirit of questioning established ideas. He suggests that the situation has deep roots in Indian culture and tradition. I disagree. Creativity can and
September 2010
·
16 Reads
·
3 Citations
Current Science
In the seamless spectrum of human knowledge from the humanities to the 'basic' sciences, earth-science and physical sciences occupy their own bandwidths.
August 2010
·
414 Reads
·
28 Citations
Physics Today
The quantitative study of heat became feasible in the early 18th century when Daniel Fahrenheit (1686-1736) invented a mercury thermometer capable of reproducible measurements. Even earlier, however, at the turn of the century, Guillaume Amontons (1663-1705) had intuitively surmised that heat flowed in solids in the direction of decreasing temperature and that temperature varied in some predictable manner with distance - Amontons himself thought the variation was linear. In 1761 Joseph Black (1728-99) introduced the concepts of latent heat and specific heat, both of which pertain to heat storage rather than to heat movement. With the invention of the calorimeter in the 1780s by Antoine Lavoisier (1743-94) and Pierre Simon Laplace (1749-1827), the latent heat of melting ice proved to be a standard for quantifying heat. The nature of what had been quantified, though, would elude comprehension throughout the 19th century.
August 2010
·
13 Reads
·
1 Citation
Current Science
July 2010
·
21 Reads
·
7 Citations
Economic and Political Weekly
India's annually renewable water resources are finite, subject to uncertain climatic variability. These resources have to be systematically monitored and managed to meet the legitimate needs of a diverse society. Ideally, a unifying national water policy to enable rational water management will give consideration to scientific knowledge of the nature of the resource within the set of human values to which India's democracy is committed.
June 2010
·
10 Reads
·
4 Citations
Physics Today
Citations (69)
... For example, Narasimhan [1989] proposed to solve multidimensional unsaturated flow through a series of one-dimensional, time-varying, discrete flow tubes of nonuniform crosssectional area; Cacas et al. [1990a, b] developed discrete fracture network models and considered channeling within the fracture plane; Sahimi [1995] described fractal concepts and percolation theory as alternative approaches to simulate flow through fractured rocks; Pruess [1999] and Pruess et al. [1999] discussed a number of alternative approaches including highresolution modeling, discrete fracture network modeling, and transfer functions, as well as chaos and fractal theory. ...
- Citing Chapter
January 1989
... There is a need to see women's role beyond the reproductive role towards their empowerment, which is possible only through economic empowerment. The National Policy for Empowerment of Women, 2001 adopted in the Ninth Five-Year Plan stated that the 'Application of science and technology is vital for the advancement of women (Kumar 2008). Technology will reduce household drudgery and provide better working conditions for women, particularly in rural areas, with emphasis on the improvement of the environment and quality of women's lives at affordable cost (Sangar 2014). ...
- Citing Article
May 2006
Current Science
... The results of a physical-based, discrete (or numerical) model are reliable and useful only if the following conditions are met: the physics is properly described, i.e., the phenomenological laws that are applied [1] are appropriate to describe physical phenomena at the relevant scale; the numerical methods are accurate and properly respect conservation principles (the basic principles of conservation of mass, energy, linear momentum, etc.); the parameters used in the model are correct, i.e., the model is properly calibrated and validated. ...
- Citing Article
September 1999
Journal of Earth System Science
... Ownership of land does not entitle a landowner to the use of surface water or groundwater. Except for small quantities of water, all users are required to obtain permits issued within the framework of scientific water management (Narasimhan, 2007). In the state of Sikkim water from most of the springs is used by private parties for drinking purposes. ...
- Citing Article
October 2007
Current Science
... Critics, however, claimed that it was not proved successful. Later on, it is emphasized that, instead of economic commodity, water should be used as a social welfare product (Narasiman & Gaur, 2010). The policy was ambiguous and did not envisage the clear rules for the water commercial use, particularly about ground-water, which has continuously been depleting (Levermann et al, 2009). ...
- Citing Article
July 2010
Economic and Political Weekly
... Several applications of the dual porosity approach are found in the literature (e.g., Gerke and Van Genuchten, 1993;Larsson and Jarvis, 1999;Delshad et al., 2002;Taron and Elsworth, 2009). An important extension of the dual porosity model is the multiple interacting continua or ''MINC'' model (Narasimhan and Pruess, 1988). With this approach, several ''hierarchies'' of heterogeneity, or sets of parallel continua at a given hierarchy level, can be set depending on the data availability. ...
- Citing Chapter
January 1988
... Modeling of partially saturated infiltration in fractured porous rock has undergone vast developments over the past years. A broad spectrum of field-scale modeling approaches employed macroscale continuum models based on large-scale volume averaging, which do not capture the flow phenomena mentioned above (Nitao, 1991;Peters & Klavetter, 1988;Pruess & Narasimhan, 1985;Wang & Narasimhan, 1985, 1992. To address these findings and the non-equilibrium between fractures and the rock matrix, models that treat both separately (dual-domain models) were developed, often combined with transfer functions, which offer a simple way to account for the mass transfer between the two domains (Neuweiler et al., 2012). ...
- Citing Chapter
December 1993
... The fluid velocity can be defined using the Darcy-Buckingham law (Buckingham, 1907;Narasimhan, 2004), which is the unsaturated version of Darcy's law, as follows: ...
- Citing Article
November 2004
... Satellitebased estimates of groundwater (Rodell, Velicogna, & Famiglietti, 2009) from three states of India-Rajasthan, Punjab, and Haryana (including Delhi)-show that irrigation may have contributed to about half of India's annual groundwater extraction between August 2002 andOctober 2008. Groundwater regulation in India operates through state-level policies with states adopting different strategies and combinations of instruments (Narasimhan, 2008;Shah, 2014). The federal government affects groundwater regulations through the promotion of "Model" forms of groundwater regulation that operate both on the demand and on the supply side (Birkenholtz, 2017;Foster, Tuinhof, Kemper, Garduño, & Nanni, 2003). ...
- Citing Article
January 2008
Economic and Political Weekly
... In particular, because of the formation of the seepage face at the tunnel walls [20][21][22][23][24], boundary conditions for numerical simulations of seepage into the tunnels are based on assigning the atmospheric pressure at the tunnel walls and a constant hydraulic head boundary condition along the tunnel perimeter [25][26][27][28]. The literature review shows that there is no generalized theory to assess the performance of ARWs [11,29,30], and determination of seepage characteristics of ARWs is based on using methods developed for conventional pumping wells [4,[31][32][33][34][35][36][37][38][39]. ...
- Citing Article
March 1991