Solar rechargeable battery—principle and materials

A brief survey of the historical development of a photoelectrochemical solar cell is given. The principle and future of solar chargeable battery is compared with a wet and a dry type photovoltaic cell. A solar chargeable battery, with or without a membrane and with an aqueous solution or with solid-state electrolytes is discussed. A new unique type of configuration “Sharon-Schottky” junction solar cell is described which can be used either as a charger for any secondary batteries or could be used for photoelectrolysis of water. All these configurations and their relative merits are discussed. A review on the various semiconductors and types of solar chargeable batteries is made. Finally, a conclusion is drawn for future direction of research for developing an economically viable photoelectrochemical (PEC) solar cell based on either the principle of a solar charger (to charge a Ni---Cd battery or lead—acid battery) and/or solar chargeable battery with or without without a membrane. Some new innovative ideas for the preparation of materials is discussed. The entire discussion is geared towards answering a relevant question: what has gone wrong to result in the stagnation and failure in commercialization of a PEC based solar cell?

Generation of spectrum compatible accelerograms

In this paper a new method is presented for generating earthquake accelerograms which have pre-established response spectra. The non-stationary random nature and other salient features of the accelerograms can be taken care of by the procedure developed. The method leads to a sample spectrum which lies above the given spectrum. The generation of records to suit several spectra simultaneously can also be handled by this approach. The method is detailed first. This is followed by several numerical examples.

A Comparative Study of the Effect of Metallic Au and ReO3 Nanoparticles on the Performance of Silicon Solar Cells

The influence of gold (similar to 35 nm diameter) as well as ReO3 (similar to 17 nm diameter) nanoparticles placed atop silicon photovoltaic devices on absorption and photocurrent generation has been investigated. The nanoparticles improve the power transmission into the semiconductor and consequently, the photocurrent response at wavelengths corresponding to plasmon absorption. An increase in short circuit current up to 4.5% under simulated solar irradiation was observed with the ReO3 nanoparticles, while the gold nanoparticles showed enhancements up to 6.5%. The increase in photocurrent is observed at wavelengths corresponding to the maxima in the surface plasmon resonance absorption spectra. (C) 2010 The Japan Society of Applied Physics

Hybrid Solar Cooking

In the existing traditional solar cookers, the cooking is performed near the collector which may be at an inconvenient location for cooking purposes. This paper proposes a hybrid solar cooking system where the solar energy is brought to the kitchen. The energy source is a combination of the solar thermal energy and the Liquefied Petroleum Gas (LPG) that is very common in kitchens. The solar thermal energy is transferred to the kitchen by means of a circulating fluid like oil. The transfer of solar heat is a two fold process wherein the energy from the collector is transferred first to an intermediate energy storage tank and then the energy is subsequently transferred from the tank to the cooking load. There are three parameters that are controlled in order to maximize the energy transfer from the collector to the load viz. the fluid flow rate from collector to tank, fluid flow rate from tank to load and the diameter of the pipes. The entire system is modeled using the bond graph approach. This paper discusses the implementation of such a system.

Performance of a small solar pond in the tropics

The performance of the 240 m2 solar pond in Bangalore is discussed. The problems of erosion of gradient zone and formation of internal convective zones is highlighted. The technique of passive salt addition is shown to be a viable alternative for salt recycling. Different techniques of heat extraction are discussed and the use of an immersed copper heat exchanger is shown to be most convenient. A two-zone model for prediction of the seasonal structure of the solar pond performance is proposed. The model is shown to simulate the seasonal structure of the observed variation of the temperature in the storage zone.

Locating the seat of the solar dynamo

The hypothesis that the solar dynamo operates in a thin layer at the bottom of the convection zone is addressed. Recent work on the question whether the magnetic flux can be made to emerge at sunspot latitudes is reviewed. It is concluded that this hypothesis can fit the observational facts only if there is turbulence with a length scale of a few hundred kilometers in and around the dynamo region.

Analysis of the Ce 3d-4d4d Auger spectrum with the use of synchrotron radiation

We report 3d-4d4d Auger spectra of Ce metal with the use of synchrotron radiation to excite the initial core hole. By sweeping the excitation energy through the 3d-->4f threshold, it has been possible to excite different initial states selectively, enabling us to analyze the complex spectrum in terms of different contributions arising from various deca channels.

Analysis of the Gd 4d-XY Auger spectrum using synchrotron radiation

We report the 4d-XY (X, Y = 5p, 4f, and the conduction band) Auger spectra of clean Gd using a monochromatic photon source with energies above and below the 3d threshold. The spectra with higher hv show the existence of intense spectator-hole Auger transitions. Comparison of these spectra with those obtained with a primary electron source allows detailed interpretation of the various features and explains the unusual spin polarization of the electron-induced spectrum reported earlier.

Solar pond technology

Solar pond technology has made substantial progress in the last fifteen years. This paper reviews the basic principles of solar ponds and the problems encountered in their operation and maintenance. The factors which influence the technical and economic viability of solar ponds for thermal applications and power generation have been discussed.

The Waldmeier effect and the flux transport solar dynamo

We confirm that the evidence for the Waldmeier effect WE1 (the anticorrelation between rise times of sunspot cycles and their strengths) and the related effect WE2 (the correlation between rise rates of cycles and their strengths) is found in different kinds of sunspot data. We explore whether these effects can be explained theoretically on the basis of the flux transport dynamo models of sunspot cycles. Two sources of irregularities of sunspot cycles are included in our model: fluctuations in the poloidal field generation process and fluctuations in the meridional circulation. We find WE2 to be a robust result which is produced in different kinds of theoretical models for different sources of irregularities. The Waldmeier effect WE1, on the other hand, arises from fluctuations in the meridional circulation and is found only in the theoretical models with reasonably high turbulent diffusivity which ensures that the diffusion time is not more than a few years.

Synthesis and photocatalytic properties of AgLi1/3Ru2/3]O-2: A new delafossite oxide

A new delafossite oxide, AgLi1/3Ru2/3]O-2, synthesized by ion-exchanging interlayer-Li+ with Ag+ in layered Li2RuO3, is reported. The transformation of layered Li2RuO3 (monoclinic, space group C2/c) to AgLi1/3Ru2/3]O-2 possessing a delafossite structure (space group R (3) over barm) has been established with powder X-ray diffraction. The successful conversion of LiLi1/3Ru2/3]O-2 to AgLi1/3Ru2/3]O-2 is further confirmed by EDAX analysis. The diffuse reflectance spectrum of AgLi1/3Ru2/3]O-2 shows broad absorption in the UV-visible region suggesting its use as a photocatalyst. The photocatalytic activity of AgLi1/3Ru2/3]O-2 has been investigated by degrading various dyes. It showed significant photocatalytic activity for dye degradation both under UV and solar radiation. (C) 2010 Elsevier B.V. All rights reserved.

Proposed visible emission line space solar coronagraph

The outer atmosphere of the sun called the corona has been observed during total solar eclipse for short periods (typically <6 min), from as early as the eighteenth century. In the recent past, space-based instruments have permitted us to study the corona uninterruptedly. In spite of these developments, the dynamic corona and its high temperature (1-2 million K) are yet to be Ally understood. It is conjectured that their dynamic nature and associated energetic events are possible reasons behind the high temperature. In order to study these in detail, a visible emission line space solar coronagraph is being proposed as a payload under the small-satellite programme of the Indian Space Research Organisation. The satellite is named as Aditya-1 and the scientific objectives of this payload are to study: (i) the existence of intensity oscillations for the study of wave-driven coronal heating; (ii) the dynamics and formation of coronal loops and temperature structure of the coronal features; (iii) the origin, cause and acceleration of coronal mass ejections (CMEs) and other solar active features, and (iv) coronal magnetic field topology and three-dimensional structures of CMEs using polarization information. The uniqueness of this payload compared to previously flown space instruments is as follows: (a) observations in the visible wavelength closer to the disk (down to 1.05 solar radii); (b) high time cadence capability (better than two-images per second), and (c) simultaneous observations of at least two spectral windows all the time and three spectral windows for short durations.

Application of a modified z-cosy experiment for the analysis of spectra of oriented molecules - the spectrum of cis,cis-mucanonitrile

NMR spectra of cis,cis-mucanonitrile oriented in a liquid crystal have been analysed using the connectivity information obtained from a modified Z-COSY experiment which provided crucial clues for the starting parameters for the iterative analysis. The proton spectra with and without C-13 satellites and the C-13 spectra have thus been interpreted. The indirect spin-spin couplings required for the analyses have been obtained from the corresponding isotropic spectra. The H-1-H-1 and C-13-H-1 dipolar couplings so obtained have been utilized to determine the relative internuclear distances. The results indicate that the molecule is planar. (C) 1994 Academic Press, Inc.