1,216 research outputs found

    Cogeneration Technology Alternatives Study (CTAS). Volume 3: Industrial processes

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    Cogenerating electric power and process heat in single energy conversion systems rather than separately in utility plants and in process boilers is examined in terms of cost savings. The use of various advanced energy conversion systems are examined and compared with each other and with current technology systems for their savings in fuel energy, costs, and emissions in individual plants and on a national level. About fifty industrial processes from the target energy consuming sectors were used as a basis for matching a similar number of energy conversion systems that are considered as candidate which can be made available by the 1985 to 2000 time period. The sectors considered included food, textiles, lumber, paper, chemicals, petroleum, glass, and primary metals. The energy conversion systems included steam and gas turbines, diesels, thermionics, stirling, closed cycle and steam injected gas turbines, and fuel cells. Fuels considered were coal, both coal and petroleum based residual and distillate liquid fuels, and low Btu gas obtained through the on site gasification of coal. An attempt was made to use consistent assumptions and a consistent set of ground rules specified by NASA for determining performance and cost. Data and narrative descriptions of the industrial processes are given

    Design of an N^7-Glycosylated Purine Nucleoside for Recognition of GC Base Pairs by Triple Helix Formation

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    Pyrimidine oligodeoxyribonucleotides bind in the major groove of DNA parallel to the purine Watson-Crick strand by formation of specific hydrogen bonds between thymine and adenine (T•AT triplet) and protonated cytosine and guanine (C+GC triplet) on the Hoogsteen face of the purine base. Alternatively, purine oligodeoxyribonucleotides bind in an antiparallel orientation relative to the purine Watson-Crick strand by formation of G•GC and A•AT triplets. The prerequisite protonation of cytosine in C+GC triplets leads to a considerable pH dependence in the binding affinity of C-containing oligodeoxyribonucleotides (Figure 1). Substitution of 5-methylcytosine (^mC) for cytosine results in increased binding affinities near physiological pH. In an attempt to eliminate the necessity for protonation, recent efforts have been directed toward the synthesis of nonnatural nucleosides which display the hydrogen bonding functionality of protonated cytosine

    Using a prisoner advisory group to develop diversity research in a maximum-security prison

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    This paper addresses groupwork processes with a group of prisoners advising a research project in a maximum-security prison in England. The research project (Appreciative Inquiry into the Diversity Strategy of HMP Wakefield. RES-000-22-3441) was funded by the Economic and Social Research Council (ESRC) and lasted 9 months. The research explored the experiences of prisoners in diverse minority groupings and the strategies of the prison to accommodate the complex needs of these groups. The Prisoner Advisory Group (PAG) was made up of representatives from Black and Minority Ethnic (BME) prisoners; older prisoners (over 60s); Disabled prisoners (with physical disabilities, learning difficulties; and mental health problems); Gay, Bi-sexual and Transgender prisoners; and prisoners affiliated to Faith groups. It met regularly during the research. The paper considers the forming norming and performing aspects of establishing an effective participant voice in a prison-based project. It considers the contribution of the PAG to developing a research strategy that engaged prisoners in the research. It reflects on the nature of ‘participative research’ in general and whether such research is possible within a high-security prison environment

    Characterization of the Crab Pulsar's Timing Noise

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    We present a power spectral analysis of the Crab pulsar's timing noise, mainly using radio measurements from Jodrell Bank taken over the period 1982-1989. The power spectral analysis is complicated by nonuniform data sampling and the presence of a steep red power spectrum that can distort power spectra measurement by causing severe power ``leakage''. We develop a simple windowing method for computing red noise power spectra of uniformly sampled data sets and test it on Monte Carlo generated sample realizations of red power-law noise. We generalize time-domain methods of generating power-law red noise with even integer spectral indices to the case of noninteger spectral indices. The Jodrell Bank pulse phase residuals are dense and smooth enough that an interpolation onto a uniform time series is possible. A windowed power spectrum is computed revealing a periodic or nearly periodic component with a period of about 568 days and a 1/f^3 power-law noise component with a noise strength of 1.24 +/- 0.067 10^{-16} cycles^2/sec^2 over the analysis frequency range 0.003 - 0.1 cycles/day. This result deviates from past analyses which characterized the pulse phase timing residuals as either 1/f^4 power-law noise or a quasiperiodic process. The analysis was checked using the Deeter polynomial method of power spectrum estimation that was developed for the case of nonuniform sampling, but has lower spectral resolution. The timing noise is consistent with a torque noise spectrum rising with analysis frequency as f implying blue torque noise, a result not predicted by current models of pulsar timing noise. If the periodic or nearly periodic component is due to a binary companion, we find a companion mass > 3.2 Earth masses.Comment: 53 pages, 9 figures, submitted to MNRAS, abstract condense

    Error estimation and reduction with cross correlations

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    Besides the well-known effect of autocorrelations in time series of Monte Carlo simulation data resulting from the underlying Markov process, using the same data pool for computing various estimates entails additional cross correlations. This effect, if not properly taken into account, leads to systematically wrong error estimates for combined quantities. Using a straightforward recipe of data analysis employing the jackknife or similar resampling techniques, such problems can be avoided. In addition, a covariance analysis allows for the formulation of optimal estimators with often significantly reduced variance as compared to more conventional averages.Comment: 16 pages, RevTEX4, 4 figures, 6 tables, published versio

    Design of an N^7-Glycosylated Purine Nucleoside for Recognition of GC Base Pairs by Triple Helix Formation

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    Pyrimidine oligodeoxyribonucleotides bind in the major groove of DNA parallel to the purine Watson-Crick strand by formation of specific hydrogen bonds between thymine and adenine (T•AT triplet) and protonated cytosine and guanine (C+GC triplet) on the Hoogsteen face of the purine base. Alternatively, purine oligodeoxyribonucleotides bind in an antiparallel orientation relative to the purine Watson-Crick strand by formation of G•GC and A•AT triplets. The prerequisite protonation of cytosine in C+GC triplets leads to a considerable pH dependence in the binding affinity of C-containing oligodeoxyribonucleotides (Figure 1). Substitution of 5-methylcytosine (^mC) for cytosine results in increased binding affinities near physiological pH. In an attempt to eliminate the necessity for protonation, recent efforts have been directed toward the synthesis of nonnatural nucleosides which display the hydrogen bonding functionality of protonated cytosine

    Efficient simulation of the random-cluster model

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    The simulation of spin models close to critical points of continuous phase transitions is heavily impeded by the occurrence of critical slowing down. A number of cluster algorithms, usually based on the Fortuin-Kasteleyn representation of the Potts model, and suitable generalizations for continuous-spin models have been used to increase simulation efficiency. The first algorithm making use of this representation, suggested by Sweeny in 1983, has not found widespread adoption due to problems in its implementation. However, it has been recently shown that it is indeed more efficient in reducing critical slowing down than the more well-known algorithm due to Swendsen and Wang. Here, we present an efficient implementation of Sweeny's approach for the random-cluster model using recent algorithmic advances in dynamic connectivity algorithms.Comment: RevTeX 4.1, 14 pages, 8 figures, 3 tables, version as publishe

    Point process model of 1/f noise versus a sum of Lorentzians

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    We present a simple point process model of 1/fβ1/f^{\beta} noise, covering different values of the exponent β\beta. The signal of the model consists of pulses or events. The interpulse, interevent, interarrival, recurrence or waiting times of the signal are described by the general Langevin equation with the multiplicative noise and stochastically diffuse in some interval resulting in the power-law distribution. Our model is free from the requirement of a wide distribution of relaxation times and from the power-law forms of the pulses. It contains only one relaxation rate and yields 1/fβ1/f^ {\beta} spectra in a wide range of frequency. We obtain explicit expressions for the power spectra and present numerical illustrations of the model. Further we analyze the relation of the point process model of 1/f1/f noise with the Bernamont-Surdin-McWhorter model, representing the signals as a sum of the uncorrelated components. We show that the point process model is complementary to the model based on the sum of signals with a wide-range distribution of the relaxation times. In contrast to the Gaussian distribution of the signal intensity of the sum of the uncorrelated components, the point process exhibits asymptotically a power-law distribution of the signal intensity. The developed multiplicative point process model of 1/fβ1/f^{\beta} noise may be used for modeling and analysis of stochastic processes in different systems with the power-law distribution of the intensity of pulsing signals.Comment: 23 pages, 10 figures, to be published in Phys. Rev.
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