Universalization of access to modern energy services in Indian households-Economic and policy analysis

Provision of modern energy services for cooking (with gaseous fuels)and lighting (with electricity) is an essential component of any policy aiming to address health, education or welfare issues; yet it gets little attention from policy-makers. Secure, adequate, low-cost energy of quality and convenience is core to the delivery of these services. The present study analyses the energy consumption pattern of Indian domestic sector and examines the urban-rural divide and income energy linkage. A comprehensive analysis is done to estimate the cost for providing modern energy services to everyone by 2030. A public-private partnership-driven business model, with entrepreneurship at the core, is developed with institutional, financing and pricing mechanisms for diffusion of energy services. This approach, termed as EMPOWERS (entrepreneurship model for provision of wholesome energy-related basic services), if adopted, can facilitate large-scale dissemination of energy-efficient and renewable technologies like small-scale biogas/biofuel plants, and distributed power generation technologies to provide clean, safe, reliable and sustainable energy to rural households and urban poor. It is expected to integrate the processes of market transformation and entrepreneurship development involving government, NGOs, financial institutions and community groups as stakeholders. (C) 2009 Elsevier Ltd. All rights reserved.

Adsorption-desorption and photocatalytic properties of inorganic-organic hybrid cadmium thiosulfate compounds

Three inorganic-organic hybrid framework cadmium thiosulfate phases have been investigated for adsorption and photodegradation of organic dye molecules. Different classes of organic dyes, viz., triaryl methane, azo, xanthene, anthraquinone, have been studied. The anionic dyes with sulfonate groups appear to readily adsorb on the cadmium thiosulfate compounds in an aqueous medium. The adsorption of the dye molecules, however, does not create any structural changes on the cadmium thiosulfate compounds, though weak electronic interactions have been observed. The adsorbed dyes have been desorbed partially in an alcoholic medium, suggesting possible applications in scavenging specific anionic dyes from the aqueous solutions. Langmuir adsorption/desorption isotherms have been used to model this behavior. UV-assisted (lambda(max) = 365 nm) photocatalytic decomposition studies on the cationic dyes indicate reasonable activity comparable with that of Degussa P-25 (TiO2) catalyst. Sunlight assisted photocatalyti studies have been carried out in detail employing hybrid framework compounds. The Langmuir-Hinshelwood kinetics model, employed to follow the degradation profile of the organic dyes, indicates that the photocatalytic degradation follows the order: triaryl methane > azo > xanthene.

An Experimental Study on Energy Absorption Behavior of Polyurethane Foams

This article is concerned with a study on the energy absorption behavior of polyurethane (PU) foams such as flexible high resilience (HR), flexible viscoelastic (VE) and semi-rigid (SR) foams as a function of the overall foam density. Foam samples were prepared in the form of cubes by mixing appropriate polyol and isocyanate compounds produced by Huntsman International India Pvt. Ltd. in varying proportions leading to a range of densities for each type of foam. The cubical samples were tested under compressive load in a standard UTM. Based on the measured load-displacement behaviors, variations of peak load and energy-absorption attributes with respect to density are plotted for each type of foam and the possible existence of an optimum foam density is shown.

A Search for Energy Minimized Sequences of Proteins

In this paper, we present numerical evidence that supports the notion of minimization in the sequence space of proteins for a target conformation. We use the conformations of the real proteins in the Protein Data Bank (PDB) and present computationally efficient methods to identify the sequences with minimum energy. We use edge-weighted connectivity graph for ranking the residue sites with reduced amino acid alphabet and then use continuous optimization to obtain the energy-minimizing sequences. Our methods enable the computation of a lower bound as well as a tight upper bound for the energy of a given conformation. We validate our results by using three different inter-residue energy matrices for five proteins from protein data bank (PDB), and by comparing our energy-minimizing sequences with 80 million diverse sequences that are generated based on different considerations in each case. When we submitted some of our chosen energy-minimizing sequences to Basic Local Alignment Search Tool (BLAST), we obtained some sequences from non-redundant protein sequence database that are similar to ours with an E-value of the order of 10(-7). In summary, we conclude that proteins show a trend towards minimizing energy in the sequence space but do not seem to adopt the global energy-minimizing sequence. The reason for this could be either that the existing energy matrices are not able to accurately represent the inter-residue interactions in the context of the protein environment or that Nature does not push the optimization in the sequence space, once it is able to perform the function.

Allostery and conformational free energy changes in human tryptophanyl-tRNA synthetase from essential dynamics and structure networks

The interdependence of the concept of allostery and enzymatic catalysis, and they being guided by conformational mobility is gaining increased prominence. However, to gain a molecular level understanding of llostery and hence of enzymatic catalysis, it is of utter importance that the networks of amino acids participating in allostery be deciphered. Our lab has been exploring the methods of network analysis combined with molecular dynamics simulations to understand allostery at molecular level. Earlier we had outlined methods to obtain communication paths and then to map the rigid/flexible regions of proteins through network parameters like the shortest correlated paths, cliques, and communities. In this article, we advance the methodology to estimate the conformational populations in terms of cliques/communities formed by interactions including the side-chains and then to compute the ligand-induced population shift. Finally, we obtain the free-energy landscape of the protein in equilibrium, characterizing the free-energy minima accessed by the protein complexes. We have chosen human tryptophanyl-tRNA synthetase (hTrpRS), a protein esponsible for charging tryptophan to its cognate tRNA during protein biosynthesis for this investigation. This is a multidomain protein exhibiting excellent allosteric communication. Our approach has provided valuable structural as well as functional insights into the protein. The methodology adopted here is highly generalized to illuminate the linkage between protein structure networks and conformational mobility involved in the allosteric mechanism in any protein with known structure.

Magnetic energy dissipation in force-free jets

It is shown that a magnetic-pressure-dominated, supersonic jet which expands (or contracts) in response to variations in the confining external pressure can dissipate magnetic energy through field-line reconnection as it relaxes to a minimum-energy configuration. In order for a continuous dissipation to take place, the effective reconnection time must be a fraction ɛ ⪉ 1 of the expansion time. The amount of energy dissipation is calculated, and it is concluded that magnetic energy dissipation could, in principle, power the observed synchrotron emission in extragalactic radio jets such as NGC 6251. However, this mechanism is only viable if the reconnection time is substantially shorter than the nominal resistive tearing time in the jet.

Embodied energy in cement stabilised rammed earth walls

Rammed earth walls are low carbon emission and energy efficient alternatives to load bearing walls. Large numbers of rammed earth buildings have been constructed in the recent past across the globe. This paper is focused on embodied energy in cement stabilised rammed earth (CSRE) walls. Influence of soil grading, density and cement content on compaction energy input has been monitored. A comparison between energy content of cement and energy in transportation of materials, with that of the actual energy input during rammed earth compaction in the actual field conditions and the laboratory has been made. Major conclusions of the investigations are (a) compaction energy increases with increase in clay fraction of the soil mix and it is sensitive to density of the CSRE wall, (b) compaction energy varies between 0.033 MJ/m(3) and 0.36 MJ/m(3) for the range of densities and cement contents attempted, (c) energy expenditure in the compaction process is negligible when compared to energy content of the cement and (d) total embodied energy in CSRE walls increases linearly with the increase in cement content and is in the range of 0.4-0.5 GJ/m(3) for cement content in the rage of 6-8%. (C) 2009 Elsevier B.V. All rights reserved.

BCN:A Graphene Analogue with Remarkable Adsorptive Properties

A new analogue of graphene containing boron, carbon and nitrogen (BCN) has been obtained by the reaction of high-surface-area activated charcoal with a mixture of boric acid and urea at 900 degrees C. X-ray photoelectron spectroscopy and electron energy-loss spectroscopy reveal the composition to be close to BCN. The X-ray diffraction pattern, high-resolution electron microscopy images and Raman spectrum indicate the presence of graphite-type layers with low sheet-to-sheet registry. Atomic force microscopy reveals the sample to consist of two to three layers of BCN, as in a few-layer graphene. BCN exhibits more electrical resistivity than graphene, but weaker magnetic features. BCN exhibits a surface area of 2911 m(2)g(-1), which is the highest value known for a BxCyNz composition. It exhibits high propensity for adsorbing CO2 (approximate to 100 wt %) at 195 K and a hydrogen uptake of 2.6 wt % at 77 K. A first-principles pseudopotential-based DFT study shows the stable structure to consist of BN3 and NB3 motifs. The calculations also suggest the strongest CO2 adsorption to occur with a binding energy of 3.7 kJ mol(-1) compared with 2.0 kJ mol(-1) on graphene.

Abatement of fluoride from water using manganese dioxide-coated activated alumina

Batch adsorption of fluoride onto manganese dioxide-coated activated alumina (MCAA) has been studied. Adsorption experiments were carried out at various pH (3–9), time interval (0–6 h), adsorbent dose (1–16 g/l), initial fluoride concentration (1–25 mg/l) and in the presence of different anions. Adsorption isotherms have been modeled using Freundlich, Langmuir and Dubinin–Raduskevich isotherms and adsorption followed Langmuir isotherm model. Kinetic studies revealed that the adsorption followed second-order rate kinetics. MCAA could remove fluoride effectively (up to 0.2 mg/l) at pH 7 in 3 h with 8 g/l adsorbent dose when 10 mg/l of fluoride was present in 50 ml of water. In the presence of other anions, the adsorption of fluoride was retared. The mechanism of fluoride uptake by MCAA is due to physical adsorption as well as through intraparticle diffusion which was confirmed by kinetics, Dubinin–Raduskevich isotherm, zeta-potential measurements and mapping studies of energy-dispersive analysis of X-ray.

Adsorption of Nitrogen on Activated Carbon-Refit of Experimental Data and Derivation of Properties Required for Design of Equipment

Volumetric method based adsorption measurements of nitrogen on two specimens of activated carbon (Fluka and Sarabhai) reported by us are refitted to two popular isotherms, namely, Dubunin−Astakhov (D−A) and Toth, in light of improved fitting methods derived recently. Those isotherms have been used to derive other data of relevance in design of engineering equipment such as the concentration dependence of heat of adsorption and Henry’s law coefficients. The present fits provide a better representation of experimental measurements than before because the temperature dependence of adsorbed phase volume and structural heterogeneity of micropore distribution have been accounted for in the D−A equation. A new correlation to the Toth equation is a further contribution. The heat of adsorption in the limiting uptake condition is correlated with the Henry’s law coefficients at the near zero uptake condition.

A universal relation for the cohesive energy of nanoparticles

A universal relation between the cohesive energy and the particle size has been predicted based on the liquid-drop model. The universal relation is well supported by other theoretical models and the available experimental data. The universal relations for intermediate size range as well as for particles with very few atoms are discussed. A comparison of onset temperature of evaporation also establishes a universal relation.

Correlation between conductivity or diffusivity and activation energy in amorphous solids

There exist many investigations of ionic transport in a variety of glasses. These studies exhibit strong correlation between ionic conductivity and activation energy: Typically, it is found that higher conductivity is associated with lower activation energies and vice versa. Although there are explanations for this at a phenomenological level, there is no consistent physical picture to explain the correlation between conductivity and activation energy. We have carried out molecular dynamics simulation as a function of the size of the impurity atom or diffusant (both neutral and charged) in a host amorphous matrix. We find that there is a maximum in self-diffusivity as a function of the size of the impurity atom suggesting that there is an appropriate size for which the diffusivity is maximum. The activation energy is found to be the lowest for this size of the impurity. A similar maximum has been previously found in other condensed phases, such as confined fluids and dense liquids, and has its origin in the levitation effect. The implications of this result for understanding ionic conductivity in glasses are discussed. Our results suggest that there is a relation between microscopic structure of the amorphous solid, diffusivity or conductivity, and activation energy. The nature of this relationship is discussed in terms of the levitation parameter showing that diffusivity is maximum when the size of the neck or doorway radius is comparable with the size of the diffusant. Our computational results here are in excellent agreement with independent experimental results of Nascimento et al. [Braz. J. Phys. 35, 626 (2005)] that structural features of the glass are important in determining the ionic conductivity.

High energy oxygen ion induced modifications in lead based perovskite thin films

The lead based ferroelectric PbZr0.53Ti0.47O3 (PZT), (Pb0.90La0.10)TiO3 (PLT10) and (Pb0.80La0.20)TiO3 (PLT20) thin films, prepared by pulsed laser ablation technique, were studied for their response to the 70 MeV oxygen ion irradiation. The dielectric analysis, capacitance-voltage (C- V) and DC leakage current measurements were performed before and after the irradiation to high-energy oxygen ions. The irradiation produced considerable changes in the dielectric, C-V, leakage characteristics and induced some amount of amorphization. The PZT films showed partial recrystallization after a thermal annealing at 400 degrees C for 10 min. The phase transition temperature [T-c] of PLT20 increased from 115 degrees C to 120 degrees C. The DC conductivity measurements showed a shift in the onset of non-linear conduction region. The current density decreased by two orders of magnitude after irradiation. After annealing the irradiated films at a temperature of 400 degrees C for 10 min, the films partially regained the dielectric and electrical properties. The results are discussed in terms of the irradiation-induced amorphization, the pinning of the ferroelectric domains by trapped charges and the thermal annealing of the defects generated during the irradiation. (C) 2007 Elsevier B.V. All rights reserved.

Energy efficient change detection over a MAC using physical layer fusion

We propose a simple and energy efficient distributed change detection scheme for sensor networks based on Page's parametric CUSUM algorithm. The sensor observations are IID over time and across the sensors conditioned on the change variable. Each sensor runs CUSUM and transmits only when the CUSUM is above some threshold. The transmissions from the sensors are fused at the physical layer. The channel is modeled as a multiple access channel (MAC) corrupted with IID noise. The fusion center which is the global decision maker, performs another CUSUM to detect the change. We provide the analysis and simulation results for our scheme and compare the performance with an existing scheme which ensures energy efficiency via optimal power selection.

Energy identities in water wave theory for free-surface boundary condition with higher-order derivatives

A modified form of Green's integral theorem is employed to derive the energy identity in any water wave diffraction problem in a single-layer fluid for free-surface boundary condition with higher-order derivatives. For a two-layer fluid with free-surface boundary condition involving higher-order derivatives, two forms of energy identities involving transmission and reflection coefficients for any wave diffraction problem are also derived here by the same method. Based on this modified Green's theorem, hydrodynamic relations such as the energy-conservation principle and modified Haskind–Hanaoka relation are derived for radiation and diffraction problems in a single as well as two-layer fluid.