28 research outputs found
Exotic R^4 and quantum field theory
Recent work on exotic smooth R^4's, i.e. topological R^4 with exotic
differential structure, shows the connection of 4-exotics with the
codimension-1 foliations of , SU(2) WZW models and twisted K-theory
, . These results made it possible
to explicate some physical effects of exotic 4-smoothness. Here we present a
relation between exotic smooth R^4 and operator algebras. The correspondence
uses the leaf space of the codimension-1 foliation of S^3 inducing a von
Neumann algebra as description. This algebra is a type III_1 factor
lying at the heart of any observable algebra of QFT. By using the relation to
factor II, we showed that the algebra can be interpreted as
Drinfeld-Turaev deformation quantization of the space of flat SL(2,\mathbb{C})
connections (or holonomies). Thus, we obtain a natural relation to quantum
field theory. Finally we discuss the appearance of concrete action functionals
for fermions or gauge fields and its connection to quantum-field-theoretical
models like the Tree QFT of Rivasseau.Comment: 15 pages, 2 figures, Based on the talk presented at Quantum Theory
and Symmetries 7, Prague, August 7-13, 2011, JPconf styl
Thermal Dissociation Behavior and Dissociation Enthalpies of Methane–Carbon Dioxide Mixed Hydrates
Replacement of methane with carbon dioxide in hydrate has been proposed as a strategy for geologic sequestration of carbon dioxide (CO{sub 2}) and/or production of methane (CH{sub 4}) from natural hydrate deposits. This replacement strategy requires a better understanding of the thermodynamic characteristics of binary mixtures of CH{sub 4} and CO{sub 2} hydrate (CH{sub 4}-CO{sub 2} mixed hydrates), as well as thermophysical property changes during gas exchange. This study explores the thermal dissociation behavior and dissociation enthalpies of CH{sub 4}-CO{sub 2} mixed hydrates. We prepared CH{sub 4}-CO{sub 2} mixed hydrate samples from two different, well-defined gas mixtures. During thermal dissociation of a CH{sub 4}-CO{sub 2} mixed hydrate sample, gas samples from the head space were periodically collected and analyzed using gas chromatography. The changes in CH{sub 4}-CO{sub 2} compositions in both the vapor phase and hydrate phase during dissociation were estimated based on the gas chromatography measurements. It was found that the CO{sub 2} concentration in the vapor phase became richer during dissociation because the initial hydrate composition contained relatively more CO{sub 2} than the vapor phase. The composition change in the vapor phase during hydrate dissociation affected the dissociation pressure and temperature; the richer CO{sub 2} in the vapor phase led to a lower dissociation pressure. Furthermore, the increase in CO{sub 2} concentration in the vapor phase enriched the hydrate in CO{sub 2}. The dissociation enthalpy of the CH{sub 4}-CO{sub 2} mixed hydrate was computed by fitting the Clausius-Clapeyron equation to the pressure-temperature (PT) trace of a dissociation test. It was observed that the dissociation enthalpy of the CH{sub 4}-CO{sub 2} mixed hydrate lays between the limiting values of pure CH{sub 4} hydrate and CO{sub 2} hydrate, increasing with the CO{sub 2} fraction in the hydrate phase
Experimental and modeling study of kinetics for methane hydrate formation with tetrahydrofuran as promoter
Observation of Xe Hydrate Growth at Gas−Ice Interface by Microfocus X-ray Computed Tomography
Dissociation Enthalpies of Synthesized Multicomponent Gas Hydrates with Respect to the Guest Composition and Cage Occupancy
Application of high pressure DSC to the kinetics of formation of methane hydrate inwater-in-oil emulsion
Blood Viscosity in Subjects With Normoglycemia and Prediabetes
OBJECTIVE Blood viscosity (BV) is higher in diabetic patients and might represent a risk factor for the development of insulin resistance and type 2 diabetes. However, data in subjects with normal glucose or prediabetes are missing. In the current study, we evaluated the relationship between BV and blood glucose in subjects with normal glucose or prediabetes. RESEARCH DESIGN AND METHODS Enrolled subjects were divided into three groups according to blood glucose: group A ( n = 74), blood glucose <90 mg/dL; group B ( n = 96), blood glucose ranging from 90 to 99 mg/dL; and group C ( n = 94), blood glucose ranging from 100 to 125 mg/dL. BV was measured at 37°C with a cone-plate viscometer at shear rates ranging from 225 to 22.5 s−1. RESULTS Blood pressure, blood lipids, fibrinogen, and plasma viscosity were similar in the three groups. BMI and waist circumference were significantly increased in group C. Hematocrit ( P < 0.05) and BV ( P between 0.01 and 0.001) were significantly higher in groups B and C compared with group A. Blood glucose was significantly and inversely correlated with HDL cholesterol and directly with BMI, waist, hematocrit ( r = 0.134), and BV (from 225 s−1 to 22.5 s−1; r ranging from 0.162 to 0.131). BV at shear rate 225 s−1 was independently associated with blood glucose. CONCLUSIONS The current study shows a direct relationship between BV and blood glucose in nondiabetic subjects. It also suggests that, even within glucose values considered completely normal, individuals with higher blood glucose levels have increased BV comparable with that observed in subjects with prediabetes