Effective Field Theory Approach to High-Temperature Thermodynamics

An effective field theory approach is developed for calculating the thermodynamic properties of a field theory at high temperature $T$ and weak coupling $g$. The effective theory is the 3-dimensional field theory obtained by dimensional reduction to the bosonic zero-frequency modes. The parameters of the effective theory can be calculated as perturbation series in the running coupling constant $g^2(T)$. The free energy is separated into the contributions from the momentum scales $T$ and $gT$, respectively. The first term can be written as a perturbation series in $g^2(T)$. If all forces are screened at the scale $gT$, the second term can be calculated as a perturbation series in $g(T)$ beginning at order $g^3$. The parameters of the effective theory satisfy renormalization group equations that can be used to sum up leading logarithms of $T/(gT)$. We apply this method to a massless scalar field with a $\Phi^4$ interaction, calculating the free energy to order $g^6 \log g$ and the screening mass to order $g^5 \log g$.Comment: 40 pages, LaTeX, 5 uuecoded figure

Phenol-crotonaldehyde resins. II. Effect of crotonaldehyde purity on resin properties

Acid-catalyzed polycondensation of phenol and crotonaldehyde results in soluble thermoplastic resins over a broad range of compositions. The thermal and curing behavior of the resins are found to vary markedly with the phenol to crotonaldehyde mole ratio and the purity of crotonaldehyde. Infrared analysis of the resins and their fractions separated by column chromatography indicates that all the resins are structurally similar. The number-average molecular weights of the resins fall in the range of 400 to 600. The resins from distilled crotonaldehyde exhibit higher molecular weights than those from crude crotonaldehyde. The thermal properties of the resins are comparable to the Novolak-type phenol-formaldehyde resins. The thermoplastic nature is retained even at higher fraction of crotonaldehyde, unlike for the conventional Novolak resins

Phenol-crotonaldehyde resins. III. Curing behavior with hexamethylenetetramine

Solid thermoplastic resins were prepared by acid-catalyzed condensation of phenol and crotonaldehyde (both crude and distilled). The thermal and curing properties were compared with the conventional phenol-formaldehyde (PF) novolak resins. Phenol-crotonaldehyde (PC) resins were found to be thermoplastic even after curing with the crosslinking agent hexamethylenetetramine up to 160°C. This curing behavior was observed irrespective of the purity of the crotonaldehyde or the phenol-to-crotonaldehyde mole ratio in the resin. Postcuring of these resins at elevated temperatures yielded insoluble and infusible thermoset products. This unique thermal characteristic could lead to interesting processing possibilities for the resins. The technical feasibility of thermoplastic processing of the PC resins followed by postcure heat treatment for transforming the molded part into a thermoset has been demonstrated

Structure, growth and morphology polyphenylene sulphide

The crystaIIinity, particle size and morphology of polyphenylene sulphide synthesized under various conditions have been investigated by X-ray diffraction and scanning electron microscopy. It was found that crystaIIinity decreased from 71 to 66% with increase of reaction time. The growth of particle size as well as total polymer mass followed a time dependence of the form X = X 0 (1 -e -αt). The particle size distribution curve was noted to be sharp centring at 3 μn for short reaction time, high speed of stirring and also for low concentration of reactants. The particle morphology showed very strong dependence on various reaction parameters. Intricate sheaf-like morphology was noted for the particles at long reaction times or low stirring speeds while oblong platelet type two-dimensional morphology was noted when a low concentration of reactants was used

The non-Abelian Debye screening length beyond leading order

In quantum electrodynamics, static electric fields are screened at non-zero temperatures by charges in the plasma. The inverse screening length, or Debye mass, may be analyzed in perturbation theory and is of order $eT$ at relativistic temperatures. An analogous situation occurs when non-Abelian gauge theories are studied perturbatively, but the perturbative analysis breaks down when corrections of order $e^2 T$ are considered. At this order, the Debye mass depends on the non-perturbative physics of confinement, and a perturbative ``definition'' of the Debye mass as the pole of a gluon propagator does not even make sense. In this work, we show how the Debye mass can be defined non-perturbatively in a manifestly gauge invariant manner (in vector-like gauge theories with zero chemical potential). In addition, we show how the $O(e^2 T)$ correction could be determined by a fairly simple, three-dimensional, numerical lattice calculation of the perimeter-law behavior of large, adjoint-charge Wilson loops.Comment: 30 pages, revtex format, 9 postscript figures included using epsf.st

Management of intra-articular fractures of distal end radius in adults

Background: Incidence of intra articular fracture L/3rd radius is significantly on rise due to high velocity accidents in young and adults. Painless wrist function is of vital importance for functioning of upper extremity in almost all activities of daily living and precise function of hand. Intra articular fracture of L/3rd radius has generally gross comminution and so also small articular fragments. Orthopaedic community differ about specific implants to fix this complex injury. The present study was undertaken to know efficacy of different modalities of treatment for different fracture pattern. Comminuted intra articular fracture geometry varies widely, to fix these small fragments to achieve stable anatomical reduction is a challenging task.   Methods: It is a combined i.e. retrospective and prospective study conducted at Hardikar Hospital, Pune, India from 1999 to December 2000. Patients of intra-articular fracture of distal end radius by different modes of treatment are included in the study. 1 patient with unilateral fracture was lost for follow-up. Thus 50 fractures, in 49 patients. were included in study. Clinico-radiological assessment was carried out by Lidstrom's (1959) criteria.Results: Satisfactory early functional end results with plaster treatment is 72.2% whereas with other modality of treatment it rises to 87.5%, indicating superiority of other modalities of treatment as far as early functional end results are concerned.Conclusions: Manipulation and plaster cast method continues to be the treatment of choice in the stable intra articular distal radial fractures. Hence there is a need for a "differentiated therapy for distal radial fractures". The treatment plan for patients must be based not only on fracture pattern identified on plain radiographs but also on factors such as bone quality, bone comminution, energy of injury and associated soft tissue damage. Additional factors to be considered in individual patient are-life style associated medical conditions and compliance

Next-to-leading Order Debye Mass for the Quark-gluon Plasma

The Debye screening mass for a quark-gluon plasma at high temperature is calculated to next-to-leading order in the QCD coupling constant from the correlator of two Polyakov loops. The result agrees with the screening mass defined by the location of the pole in the gluon propagator as calculated by Rebhan. It is logarithmically sensitive to nonperturbative effects associated with the screening of static chromomagnetic fields.Comment: 8 pages, NUHEP-TH-94-1

Asymptotic Behavior of the Correlator for Polyakov Loops

The asymptotic behavior of the correlator for Polyakov loop operators separated by a large distance $R$ is determined for high temperature QCD. It is dominated by nonperturbative effects related to the exchange of magnetostatic gluons. To analyze the asymptotic behavior, the problem is formulated in terms of the effective field theory of QCD in 3 space dimensions. The Polyakov loop operator is expanded in terms of local gauge-invariant operators constructed out of the magnetostatic gauge field, with coefficients that can be calculated using resummed perturbation theory. The asymptotic behavior of the correlator is $\exp(-MR)/R$, where $M$ is the mass of the lowest-lying glueball in $(2+1)$-dimensional QCD. This result implies that existing lattice calculations of the Polyakov loop correlator at the highest temperatures available do not probe the true asymptotic region in $R$.Comment: 10 pages, NUHEP-TH-94-2

Structure, growth and morphology of polyphenylene sulphide

The crystallinity, particle size and morphology of polyphenylene sulphide synthesized from 1, 4-dibromobenzene and sodium sulphide have been investigated by X-ray diffraction and scanning electron microscopy. It was found that the crystallinity increased from 62 to 68% with an increase in reaction time. A reordering of crystalline structure with increase of reaction time was also noted. The particle size growth was slower as compared to the reaction rate and the distribution was very sharp. The results are compared with those for polyphenylene sulphide obtained from 1, 4-dichlorobenzene and sodium sulphide