719 research outputs found
Production of gaseous fuel by pyrolysis of municipal solid waste
Pilot plant tests were conducted on a simulated solid waste which was a mixture of shredded newspaper, wood waste, polyethylene plastics, crushed glass, steel turnings, and water. Tests were conducted at 1400 F in a lead-bath pyrolyser. Cold feed was deaerated by compression and was dropped onto a moving hearth of molten lead before being transported to a sealed storage container. About 80 percent of the feed's organic content was converted to gaseous products which contain over 90 percent of the potential waste energy; 12 percent was converted to water; and 8 percent remained as partially pyrolyzed char and tars. Nearly half of the carbon in the feed is converted to benzene, toluene and medium-quality fuel gas, a potential credit of over $25 per ton of solid waste. The system was shown to require minimal preprocessing and less sorting then other methods
Accelerating Markov Chain Monte Carlo sampling with diffusion models
Global fits of physics models require efficient methods for exploring
high-dimensional and/or multimodal posterior functions. We introduce a novel
method for accelerating Markov Chain Monte Carlo (MCMC) sampling by pairing a
Metropolis-Hastings algorithm with a diffusion model that can draw global
samples with the aim of approximating the posterior. We briefly review
diffusion models in the context of image synthesis before providing a
streamlined diffusion model tailored towards low-dimensional data arrays. We
then present our adapted Metropolis-Hastings algorithm which combines local
proposals with global proposals taken from a diffusion model that is regularly
trained on the samples produced during the MCMC run. Our approach leads to a
significant reduction in the number of likelihood evaluations required to
obtain an accurate representation of the Bayesian posterior across several
analytic functions, as well as for a physical example based on a global
analysis of parton distribution functions. Our method is extensible to other
MCMC techniques, and we briefly compare our method to similar approaches based
on normalizing flows. A code implementation can be found at
https://github.com/NickHunt-Smith/MCMC-diffusion.Comment: 21 pages, 8 figures, 1 tabl
Az Istállós-kői-barlang ásatásának folytatása és a Bükki Aurignaci kérdése = Continuation of Excavating Istállós-kő Cave and Problem of Bükk Aurignacian
A T046892 OTKA pályázat kutatási programja keretében 2004-2005-ben sikerült tovább folytatni az Istállós-kői-barlang, 2005-2006-ban pedig a Herman Otto-barlang revíziós ásatását elvégezni. A program keretében lehetőség nyílt a teljes Bükki-Aurignacien kultúra techno-tipológiai és komplex rétegtani-őskörnyezettani, kronológiai és paleoetnológiai feldolgozására. Szerencsés módon William Davies (University of Southampton) és Marcel Otte (Universite de Liege) C14 programjával együttműködve, több új radiometrikus kormeghatározást elvégezni a Bükki-Aurignacien kultúrával kapcsolatban. Így sor került a különleges jelentőségű Miskolc-Tapolcai-kőfülke Aurignacien koponyaleletének C14 kormeghatározására is. Az eredményeket több konferencián és publikációban mutattuk be. | The number T46892 research program funded by the OTKA, included further excavations and revisions of two main sites: the Istallós-kő (2004-2005) and the Otto Herman Cave (2005-2006). The detailed research program on the Aurignacien Culture in the Bükk Mountains, involved processing all the available data; such as the techno-tipological and the complex stratigraphical-paleoenvironmental, the chronological and the paleoethnological. Working closely with other research programs led by William Davies (University of Southampton) and Marcel Otte (Universite de Liege) we were able to perform many new C14 radiometric dating. Among others, the extremely significant one was done on the occipital bone found in Miskolc-Tapolca's Rockshelter. We have presented the results and conclusions in many conferences and in publications
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Exposure to Bisphenol A and Other Phenols in Neonatal Intensive Care Unit Premature Infants
Objective: We previously demonstrated that exposure to polyvinyl chloride plastic medical devices containing di(2-ethylhexyl) phthalate (DEHP) was associated with higher urinary concentrations of several DEHP metabolites in 54 premature infants in two neonatal intensive care units than in the general population. For 42 of these infants, we evaluated urinary concentrations of several phenols, including bisphenol A (BPA), in association with the use of the same medical devices. Measurements: We measured the urinary concentrations of free and total (free plus conjugated) species of BPA, triclosan, benzophenone-3, methyl paraben, and propyl paraben. Results: The percentage of BPA present as its conjugated species was > 90% in more than three-quarters of the premature infants. Intensity of use of products containing DEHP was strongly associated with BPA total concentrations but not with any other phenol. Adjusting for institution and sex, BPA total concentrations among infants in the group of high use of DEHP-containing products were 8.75 times as high as among infants in the low use group (p < 0.0001). Similarly, after adjusting for sex and DEHP-containing product use category, BPA total concentrations among infants in Institution A were 16.6 times as high as those among infants in Institution B (p < 0.0001). Conclusion: BPA geometric mean urinary concentration (30.3 μg/L) among premature infants undergoing intensive therapeutic medical interventions was one order of magnitude higher than that among the general population. Conjugated species were the primary urinary metabolites of BPA, suggesting that premature infants have some capacity to metabolize BPA. The differences in exposure to BPA by intensity of use of DEHP-containing medical products highlight the need for further studies to determine the specific source(s) of exposure to BPA
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Associations between stratospheric variability and tropospheric blocking
There is widely believed to be a link between stratospheric flow variability and stationary, persistent “blocking” weather systems, but the precise nature of this link has proved elusive. Using data from the ERA-40 Reanalysis and an atmospheric general circulation model (GCM) with a well-resolved stratosphere (HadGAM), it is shown that there are in fact several different highly significant associations, with blocking in different regions being related to different patterns of stratospheric variability. This is true in both hemispheres and in both data sets. The associations in HadGAM are shown to be very similar to those in ERA-40, although the model has a tendency to underestimate both European blocking and the wave number 2 stratospheric variability to which this is related. Although the focus is on stratospheric variability in general, several of the blocking links are seen to occur in association with the major stratospheric sudden warmings. In general, the direction of influence appears to be upward, as blocking anomalies are shown to modify the planetary stationary waves, leading to an upward propagation of wave activity into the stratosphere. However, significant correlations are also apparent with the zonal mean flow in the stratosphere leading the occurrence of blocking at high latitudes. Finally, the underestimation of blocking is an enduring problem in GCMs, and an example has recently been given in which improving the resolution of the stratosphere improved the representation of blocking. Here, however, another example is given, in which increasing the stratospheric resolution unfortunately does not lead to an improvement in blocking
Social democracy, embeddedness and decommodification: On the conceptual innovations and intellectual affiliations of Karl Polanyi
Of the several debates that revolve around the work of the economic historian and political economist Karl Polanyi, one that continues to exercise minds concerns his analysis of, and political attitudes toward, post-war capitalism and the welfare state. Simplified a little, it is a debate with two sides. To borrow Iván Szelényi's terms, one side constructs a ‘hard’ Karl Polanyi, the other a ‘soft’ one. The former advocated a socialist mixed economy dominated by redistributive mechanisms. He was a radical socialist for whom the market should never be the dominant mechanism of economic coordination. His ‘soft’ alter ego insisted that the market system remain essentially intact but be complemented by redistributive mechanisms. The ‘double movement’ – the central thesis of his ‘Great Transformation’ – acts, in this reading, as a self-correcting mechanism that moderates the excesses of market fundamentalism; its author was positioned within the social-democratic mainstream for which the only realistic desirable goal is a regulated form of capitalism. In terms of textual evidence there is much to be said for both interpretations. In this article I suggest a different approach, one that focuses upon the meaning of Polanyi's concepts in relation to their socio-political and intellectual environment
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