Electron Mean Energy, Secondary Ionization Coefficients And (E/P)Crit In Binary-Mixtures Of Sf6-N2 And Ccl2f2-N2

Measurements of the ratio of diffusion coefficient to mobility (D/ mu ) of electrons in SF6-N2 and CCl2F2-N2 mixtures over the range 80

Dependence of low-lying energy eigenvalues on the short- and long-range parts of confining potentials

The potential description of a quark-antiquark system seems to work very well in describing a number of hadronic properties. However, the precise form of the potential is unknown. The changes in the low-lying eigenvalues as a result of changes in the long-range part of the potential are investigated in a non-perturbative manner. It is shown by considering a variety of examples that the low-lying eigenvalues are insensitive to the long-range part of the potential.

Dark Spots, Bubbles, and Shells in the Lobes of Extragalactic Radio Sources

Based on maps of the extragalactic radio sources Cyg A, Her A, Cen A, 3C 277.3 and others, arguments are given that the twin-jets from the respective active galactic nucleus ram their channels repeatedly through thin, massive shells. The jets are thereby temporarily choked and blow radio bubbles. Warm shell matter in the cocoon shows up radio-dark through electron-scattering.

The Milky Way's Dark Matter Halo Appears To Be Lopsided

The atomic hydrogen gas (H I) disk in the outer region (beyond similar to 10 kpc from the center) of Milky Way can provide valuable information about the structure of the dark matter halo. The recent three-dimensional thickness map of the outer H I disk from the all sky 21 cm line Leiden/Argentine/Bonn survey, gives us a unique opportunity to investigate the structure of the dark matter halo of Milky Way in great detail. A striking feature of this new survey is the north-south (N-S) asymmetry in the thickness map of the atomic hydrogen gas. Assuming vertical hydrostatic equilibrium under the total potential of the Galaxy, we derive the model thickness map of the H I gas. We show that simple axisymmetric halo models, such as softened isothermal halo (producing a flat rotation curve with V-c similar to 220 km s(-1)) or any halo with density falling faster than the isothermal one, are not able to explain the observed radial variation of the gas thickness. We also show that such axisymmetric halos along with different H I velocity dispersion in the two halves, cannot explain the observed asymmetry in the thickness map. Amongst the nonaxisymmetric models, it is shown that a purely lopsided (m = 1, first harmonic) dark matter halo with reasonable H I velocity dispersion fails to explain the N-S asymmetry satisfactorily. However, we show that by superposing a second harmonic (m = 2) out of phase onto a purely lopsided halo, e. g., our best fit and more acceptable model A (with parameters epsilon(1)(h) = 0.2, epsilon(2)(h) = 0.18, and sigma(H I) = 8.5 km s(-1)) can provide an excellent fit to the observation and reproduce the N-S asymmetry naturally. The emerging picture of the asymmetric dark matter halo is supported by the. cold dark matter halos formed in the cosmological N-body simulation.

New temperature fluctuation method for direct determination of thermal activation energy of deep levels in semiconductors

A new method is suggested where the thermal activation energy is measured directly and not as a slope of an Arrhenius plot. The sample temperature T is allowed to fluctuate about a temperature T0. The reverse-biased sample diode is repeatedly pulsed towards zero bias and the transient capacitance C1 at time t1 is measured The activation energy is obtained by monitoring the fluctuations in C1 and T. The method has been used to measure the activation energy of the gold acceptor level in silicon.

Energy-dependence of nitrate reductase induction in Candida-Utilis

The requirement of a suitable energy source during the induced synthesis of nitrate reductase in Image was investigated. The levels of nitrate reductase induced were shown to be energy-dependent, and to vary in response to the type of carbon source provided. Glycerol, fructose, ethanol, glucose, and sucrose served as efficient energy sources. Growth rate of the yeast and the induced level of nitrate reductase were dependent on the ratio of carbon to nitrogen in the induction medium, and ratio of 2 being optimal. Induction of nitrate reductase was inhibited by uncouplers, 2,4-dinitrophenol (DNP), dicumarol and carbonyl cyanide Candida-Utilis -trifluoromethoxy phenyl hydrazone (CCCP), and by cyanide and azide, indicating an absolute energy-dependency. The facilitation of induction of a high level of nitrate reductase by exogenously added ATP as sole source of energy confirmed the obligate requirement of ATP for the synthesis of nitrate reductase in Candida-Utilis.

Rural energy consumption patterns - A field study

This paper is a condensed version of the final report of a detailed field study of rural energy consumption patterns in six villages located west of Bangalore in the dry belt of Karnataka State in India. The study was carried out in two phases; first, a pilot study of four villages and second, the detailed study of six villages, the populations of which varied from around 350 to about 950. The pilot survey ended in late 1976, and most of the data was collected for the main project in 1977. Processing of the collected data was completed in 1980. The aim was to carry out a census survey, rather than a sample study. Hence, considerable effort was expended in production of both a suitable questionnaire, ensuring that all respondents were contacted, and devising methods which would accurately reflect the actual energy use in various energy-utilising activities. In the end, 560 households out of 578 (97%) were surveyed. The following ranking was found for the various energy sources in order of average percentage contribution to the annual total energy requirement: firewood, 81·6%; human energy, 7·7%; animal energy, 2·7%; kerosene, 2·1%; electricity, 0·6% and all other sources (rice husks, agro-wastes, coal and diesel fuel), 5·3%. In other words commercial fuels made only a small contribution to the overall energy use. It should be noted that dung cakes are not burned in this region. The average energy use pattern, sector by sector, again on a percentage basis, was as follows: domestic, 88·3%; industry, 4·7%; agriculture, 4·3%; lighting, 2·2% and transport, 0·5%. The total annual per capita energy consumption was 12·6 ± 1·2 GJ, giving an average annual household consumption of around 78·6 GJ.

Graphical method to include temperature variation of activation energy in Hall data analysis

A graphical method is presented for Hall data analysis, including the temperature variation of activation energy due to screening. This method removes the discrepancies noted in the analysis of recently reported Hall data on Si(In).

Cooking in the ungra area: Fuel efficiency, energy losses, and opportunities for reducing firewood consumption

Cooking efficiency and related fuel economy issues have been studied in a particular rural area of India. Following a description of the cooking practices and conditions in this locale, cooking efficiency is examined. A cooking efficiency of only 6% was found. The use of aluminium rather than clay pots results in an increased efficiency. In addition, cooking efficiency correlates very well with specific fuel consumption. The latter parameter is much simpler to analyse than cooking efficiency. The energy losses during cooking are examined in the second part of this case study. The major energy losses are heating of excess air, heat carried away by the combustion products, heat transmitted to the stove body and floor, and the chemical energy in charcoal residue. The energy loss due to the evaporation of cooking water is also significant because it represents about one-third of the heat reaching the pots.

Representations and properties of para-Bose oscillator operators. I. Energy position and momentum eigenstates

Para-Bose commutation relations are related to the SL(2,R) Lie algebra. The irreducible representation [script D]alpha of the para-Bose system is obtained as the direct sum Dbeta[direct-sum]Dbeta+1/2 of the representations of the SL(2,R) Lie algebra. The position and momentum eigenstates are then obtained in this representation [script D]alpha, using the matrix mechanical method. The orthogonality, completeness, and the overlap of these eigenstates are derived. The momentum eigenstates are also derived using the wave mechanical method by specifying the domain of the definition of the momentum operator in addition to giving it a formal differential expression. By a careful consideration in this manner we find that the two apparently different solutions obtained by Ohnuki and Kamefuchi in this context are actually unitarily equivalent. Journal of Mathematical Physics is copyrighted by The American Institute of Physics.

Stereochemical studies on cyclic peptides. XIII. Energy minimization studies on cyclic hexapeptides having hydrogen bonds

The basic cyclic hexapeptide conformations which accommodate hydrogen bonded β and γ turns in the backbone have been worked out using stereochemical criteria and energy minimization procedures. It was found that cyclic hexapeptides can be made up of all possible combinations of 4 ± 1 hydrogen bonded types I, I', II and II' β turns, giving rise to symmetric conformations having twofold and inversion symmetries as well as nonsymmetric structures. Conformations having exclusive features of 3 ± 1 hydrogen bonded γ turns were found to be possible in threefold and S6 symmetric cyclic hexapeptides. The results show that the cyclic hexapeptides formed by the linking of two β turn tripeptide fragments differ mainly in (a) the hydrogen bonding scheme present in the β turn tripeptides and (b) the conformation at the α-carbon atoms where the two tripeptide fragments link. The different hydrogen bonding schemes found in the component β turns are: 1) a β turn with only a 4 ± 1 hydrogen bond, 2) a type I or I' β turn with 4 ± 1 and 3 ± 1 hydrogen bonds occurring in a bifurcated form and 3) a type II or II' β turn having both the 4 ± 1 and the 3 ± 1 hydrogen bonds with the same acceptor oxygen atom. The conformation at the linking α-carbon atoms was found to lie either in the extended region or in the 3 ± 1 hydrogen bonded γ turn or inverse γ turn regions. Further, the threefold and the S6 symmetric conformations have three γ turns interleaved by three extended regions or three inverse γ turns, respectively. The feasibility of accommodating alanyl residues of both isomeric forms in the CHP minima has been explored. Finally, the available experimental data are reviewed in the light of the present results.

Biomass based energy system for a South Indian village

The biomass resources, existing utilization levels and the efficiency of its use have been analyzed for a South Indian village. A biomass based energy efficient strategy has been devised to meet all the energy needs of the village, including substitution of fuels such as electricity and kerosene used in specific activities. Results indicate that the potential as well as the technologies exist for such substitutions. The proposed strategy will lead to an increase in the efficiency of energy use, reduce human drudgery and make villages more self reliant.

Improved bounds on the radius and curvature of the K pi scalar form factor and implications to low-energy theorems

We obtain stringent bounds in the < r(2)>(K pi)(S)-c plane where these are the scalar radius and the curvature parameters of the scalar K pi form factor, respectively, using analyticity and dispersion relation constraints, the knowledge of the form factor from the well-known Callan-Treiman point m(K)(2)-m(pi)(2), as well as at m(pi)(2)-m(K)(2), which we call the second Callan-Treiman point. The central values of these parameters from a recent determination are accomodated in the allowed region provided the higher loop corrections to the value of th form factor at the second Callan-Treiman point reduce the one-loop result by about 3% with F-K/F-pi = 1.21. Such a variation in magnitude at the second Callan-Treiman point yields 0.12 fm(2) less than or similar to < r(2)>(K pi)(S) less than or similar to 0.21 fm(2) and 0.56 GeV-4 less than or similar to c less than or similar to 1.47 GeV-4 and a strong correlation between them. A smaller value of F-K/F-pi shifts both bounds to lower values.

Enhancement of Tunneling Density of States at a Junction of Three Luttinger Liquid Wires

We study the tunneling density of states (TDOS) for a junction of three Tomonaga-Luttinger liquid wires. We show that there are fixed points which allow for the enhancement of the TDOS, which is unusual for Luttinger liquids. The distance from the junction over which this enhancement occurs is of the order of x=v/(2 omega), where v is the plasmon velocity and omega is the bias frequency. Beyond this distance, the TDOS crosses over to the standard bulk value independent of the fixed point describing the junction. This finite range of distances opens up the possibility of experimentally probing the enhancement in each wire individually.

Electron energy loss spectroscopy (EELS) of H2O, H2S, H2Se and H2Te

Electronic excitation in H2O, H2S, H2Se and H2Te molecules has been studied by the EELS technique. Spectra of H2S and H2Se are remarkably similar with the 1b1-nd transition most intense. The intensity of the first transition 1b1-nsa1 decreases through H2O to H2Se and this transition is absent in H2Te. Transitions observed by EELS have been compared with optical absorption studies. A correlation diagram of the occupied and the excited states has been provided for these four molecules by making use of UVPES and EELS.