35 research outputs found

    Enhancing the potential of industrial use of the Indian fly ashes through echano-chemical activation – prospects and problems

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    The generation of fly ash from the coal-fired thermal power stations in India is very large. At the same time, its quality is highly variable and predominantly crystalline. Since the generation is likely to touch 170 Mt in 2011-12 and about 600 Mt in 2031-32, one will have to look for newer avenues of bulk usage that have not been tried so far. This strategy requires technologies for upgradation of fly ash quality. Currently fine grinding of fly ash and cyclone classification are the technologies adopted and the product particle size reduces from a mean of 30 µm to 3-9 µm. With these particulate characteristics the properties of mortars and concrete significantly improve due to enhancement of packing density and increased number of nucleation points for cement hydration in the paste. In other words the improvement in properties is consistent with the increase in surface generation. But in Materials Science it is known that a decrease in the size of the crystals below some threshold value may result in a disproportionately large change of properties. This observation has been made profusely in the context of nanomaterials with mean size of particles below 100 nm. But there is always a region in the submicrocrystalline field of materials going up to 300 nm. This paper addresses the issues pertaining to the prospects of finding a threshold value for the Indian fly ash particles which may lead to large change of properties, which, in turn, may unfold possibilities of newer bulk applications of fly ash by virtue of such mechano-chemical activation

    Phase transitions and non-equilibrium relaxation in kinetic models of opinion formation

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    We review in details some recently proposed kinetic models of opinion dynamics. We discuss the several variants including a generalised model. We provide mean field estimates for the critical points, which are numerically supported with reasonable accuracy. Using non-equilibrium relaxation techniques, we also investigate the nature of phase transitions observed in these models. We study the nature of correlations as the critical points are approached, and comment on the universality of the phase transitions observed.Comment: 11 pages, 8 eps figures, 1 table. Contribution for proceedings of Statphys-Kolkata-VII 26-30 November, 201

    Performance Measures in Acousto-optic Chaotic Signal Encryption System Subject to Parametric Variations and Additive Noise

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    Signal encryption and recovery using chaotic optical waves has been a subject of active research in the past 10 years. Since an acousto-optic Bragg cell with zeroth- and first-order feedback exhibits chaotic behavior past the threshold for bistability, such a system was recently examined for possible chaotic encryption using a low-amplitude sinusoidal signal applied via the bias input of the sound cell driver. Subsequent recovery of the message signal was carried out via a heterodyne strategy employing a locally generated chaotic carrier, with threshold parameters matched to the transmitting Bragg cell. The simulation results, though encouraging, were limited to relatively low chaos frequencies and sinusoidal message signals only. In this paper, we extend the previous work by (i) increasing the chaos frequency using appropriate parameter control; (ii) carefully examining the system sensitivity to three system parameters, viz., feedback delay, feedback gain, and dc bias level; (iii) examine signal recoverability relative to shifts in the three parameters mentioned above relative to the transmitter; and (iv) determining the robustness of such a system relative to the primary transmitter parameters. Additionally, we consider the effect of the additive bandpass noise (obtained from white Gaussian noise in the simulator) on signal recovery in such a system from a performance standpoint. It is also conjectured that signal recovery can be effected by passing the modulated light through a second sound cell in a matched chaotic regime. This aspect is also under investigation

    Common and Unique Representations in pFC for Place Attractiveness

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    Although previous neuroimaging research has identified overlapping correlates of subjective value across different reward types in the ventromedial pFC (vmPFC), it is not clear whether this “common currency” evaluative signal extends to the aesthetic domain. To examine this issue, we scanned human participants with fMRI while they made attractiveness judgments of faces and places—two stimulus categories that are associated with different underlying rewards, have very different visual properties, and are rarely compared with each other. We found overlapping signals for face and place attractiveness in the vmPFC, consistent with the idea that this region codes a signal for value that applies across disparate reward types and across both economic and aesthetic judgments. However, we also identified a subregion of vmPFC within which activity patterns for face and place attractiveness were distinguishable, suggesting that some category-specific attractiveness information is retained in this region. Finally, we observed two separate functional regions in lateral OFC: one region that exhibited a category-unique response to face attractiveness and another region that responded strongly to faces but was insensitive to their value. Our results suggest that vmPFC supports a common mechanism for reward evaluation while also retaining a degree of category-specific information, whereas lateral OFC may be involved in basic reward processing that is specific to only some stimulus categories

    Design of Acousto-optic Chaos Based Secure Free-space Optical Communication Links

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    We discuss the design of an acousto-optic cell based free space optical communication link where the data beam is made secure through chaos encryption. Using external signal modulation of the diffracted light from a hybrid acousto-optic cell chaos (or directly via incorporation in the sound-cell driver\u27s bias voltage) encryption of data is possible. We have shown numerically that decryption of the encoded data is possible by using an identical acousto-optic system in the receiver

    Morality is in the eye of the beholder: the neurocognitive basis of the “anomalous-is-bad” stereotype

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    Are people with flawed faces regarded as having flawed moral characters? An “anomalous-is-bad” stereotype is hypothesized to facilitate negative biases against people with facial anomalies (e.g., scars), but whether and how these biases affect behavior and brain functioning remain open questions. We examined responses to anomalous faces in the brain (using a visual oddball paradigm), behavior (in economic games), and attitudes. At the level of the brain, the amygdala demonstrated a specific neural response to anomalous faces—sensitive to disgust and a lack of beauty but independent of responses to salience or arousal. At the level of behavior, people with anomalous faces were subjected to less prosociality from participants highest in socioeconomic status. At the level of attitudes, we replicated previously reported negative character evaluations made about individuals with facial anomalies, and further identified explicit biases directed against them as a group. Across these levels of organization, the specific amygdala response to facial anomalies correlated with stronger just-world beliefs (i.e., people get what they deserve), less dispositional empathic concern, and less prosociality toward people with facial anomalies. Characterizing the “anomalous-is-bad” stereotype at multiple levels of organization can reveal underappreciated psychological burdens shouldered by people who look different

    A pre-registered, multi-lab non-replication of the Action-sentence Compatibility Effect (ACE)

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    The Action-sentence Compatibility Effect (ACE) is a well-known demonstration of the role of motor activity in the comprehension of language. Participants are asked to make sensibility judgments on sentences by producing movements toward the body or away from the body. The ACE is the finding that movements are faster when the direction of the movement (e.g., toward) matches the direction of the action in the to-be-judged sentence (e.g., Art gave you the pen describes action toward you). We report on a pre-registered, multi-lab replication of one version of the ACE. The results show that none of the 18 labs involved in the study observed a reliable ACE, and that the meta-analytic estimate of the size of the ACE was essentially zero.Fil: Morey, Richard. Cardiff University; Reino UnidoFil: Kaschak, Michael. Florida State University; Estados UnidosFil: Díez Álamo, Antonio. Universidad de Salamanca; España. Arizona State University; Estados UnidosFil: Glenberg, Arthur. Arizona State University; Estados Unidos. Universidad de Salamanca; EspañaFil: Zwaan, Rolf A.. Erasmus University Rotterdam; Países BajosFil: Lakens, Daniël. Eindhoven University of Technology; Países BajosFil: Ibáñez, Santiago Agustín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de San Andrés; Argentina. University of San Francisco; Estados Unidos. Universidad Adolfo Ibañez; Chile. Trinity College Dublin; IrlandaFil: García, Adolfo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de San Andrés; Argentina. University of San Francisco; Estados Unidos. Universidad Nacional de Cuyo. Facultad de Educación Elemental y Especial; Argentina. Universidad de Santiago de Chile; ChileFil: Gianelli, Claudia. Universitat Potsdam; Alemania. Scuola Universitaria Superiore; ItaliaFil: Jones, John L.. Florida State University; Estados UnidosFil: Madden, Julie. University of Tennessee; Estados UnidosFil: Alifano Ferrero, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bergen, Benjamin. University of California at San Diego; Estados UnidosFil: Bloxsom, Nicholas G.. Ashland University; Estados UnidosFil: Bub, Daniel N.. University of Victoria; CanadáFil: Cai, Zhenguang G.. The Chinese University; Hong KongFil: Chartier, Christopher R.. Ashland University; Estados UnidosFil: Chatterjee, Anjan. University of Pennsylvania; Estados UnidosFil: Conwell, Erin. North Dakota State University; Estados UnidosFil: Wagner Cook, Susan. University of Iowa; Estados UnidosFil: Davis, Joshua D.. University of California at San Diego; Estados UnidosFil: Evers, Ellen R. K.. University of California at Berkeley; Estados UnidosFil: Girard, Sandrine. University of Carnegie Mellon; Estados UnidosFil: Harter, Derek. Texas A&m University Commerce; Estados UnidosFil: Hartung, Franziska. University of Pennsylvania; Estados UnidosFil: Herrera, Eduar. Universidad ICESI; ColombiaFil: Huettig, Falk. Max Planck Institute for Psycholinguistics; Países BajosFil: Humphries, Stacey. University of Pennsylvania; Estados UnidosFil: Juanchich, Marie. University of Essex; Reino UnidoFil: Kühne, Katharina. Universitat Potsdam; AlemaniaFil: Lu, Shulan. Texas A&m University Commerce; Estados UnidosFil: Lynes, Tom. University of East Anglia; Reino UnidoFil: Masson, Michael E. J.. University of Victoria; CanadáFil: Ostarek, Markus. Max Planck Institute for Psycholinguistics; Países BajosFil: Pessers, Sebastiaan. Katholikie Universiteit Leuven; BélgicaFil: Reglin, Rebecca. Universitat Potsdam; AlemaniaFil: Steegen, Sara. Katholikie Universiteit Leuven; BélgicaFil: Thiessen, Erik D.. University of Carnegie Mellon; Estados UnidosFil: Thomas, Laura E.. North Dakota State University; Estados UnidosFil: Trott, Sean. University of California at San Diego; Estados UnidosFil: Vandekerckhove, Joachim. University of California at Irvine; Estados UnidosFil: Vanpaeme, Wolf. Katholikie Universiteit Leuven; BélgicaFil: Vlachou, Maria. Katholikie Universiteit Leuven; BélgicaFil: Williams, Kristina. Texas A&m University Commerce; Estados UnidosFil: Ziv Crispel, Noam. BehavioralSight; Estados Unido
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