Finite-size,chemical-potential and magnetic effects on the phase transition in a four-fermion interacting model

We study effects coming from finite size, chemical potential and from a magnetic background on a massive version of a four-fermion interacting model. This is performed in four dimensions as an application of recent developments for dealing with field theories defined on toroidal spaces. We study effects of the magnetic field and chemical potential on the size-dependent phase structure of the model, in particular, how the applied magnetic field affects the size-dependent critical temperature. A connection with some aspects of the hadronic phase transition is established.     

What is modified gravity and how to differentiate it from particle dark matter?

An obvious criterion to classify theories of modified gravity is to identify their gravitational degrees of freedom and their coupling to the metric and the matter sector. Using this simple idea, we show that any theory which depends on the curvature invariants is equivalent to general relativity in the presence of new fields that are gravitationally coupled to the energy-momentum tensor. We show that they can be shifted into a new energy-momentum tensor. There is no a priori reason to identify these new fields as gravitational degrees of freedom or matter fields. This leads to an equivalence between dark matter particles gravitationally coupled to the standard model fields and modified gravity theories designed to account for the dark matter phenomenon. Due to this ambiguity, it is impossible to differentiate experimentally between these theories and any attempt of doing so should be classified as a mere interpretation of the same phenomenon.     

The Use of Low Field NMR and Thermal Analysis to the Wood Polymer Composite Study

Summary: The focus of this work was to characterize the molecular dynamic of High Impact Polystyrene (HIPS - 5% PB), wood - A (Vochysia divergens) and B (Erisma uncinatum) - and their composites, using solid state nuclear magnetic resonance (NMR), by measuring the proton spin-lattice relaxation time (T₁H) using a low field NMR, and by thermal analysis as Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). DSC and TGA measurements show that both woods present the same molecular behavior. On the other hand, the spin-lattice relaxation time observed that the water is interfering in the packing and arrangements of cellulose chains due to inter and intra hydrogen molecular interactions, promoting the T₁H values changed to high values. T₁H shows that the sample B presents a higher rigidity than sample A. However, HIPS presents higher T₁H values comparing to wood types. Analyzing the relaxation data for the composites, the values indicate that composites present an interaction between both components.     

High-spin structures of the odd-A 43 97−105 Tc isotopes

The ^99?105Tc isotopes have been produced at high spin as fission fragments following the fusion reaction ³⁷Cl(170 MeV) + ¹⁷⁶Yb and studied with the Euroball3 array. The high-spin structures of ¹⁰³Tc have been identified for the first time. From the systematics of the yrast states of ^97?105Tc, the location of individual proton states can be analyzed as a function of the neutron number.     

First identification of rotational bands in 103Tc: Evolution of intrinsic proton states of the 97-105 43Tc isotopes

High-spin states of ¹⁰³ ₄₃Tc have been identified for the first time, this nucleus being produced as fission fragment following the fusion reaction ³⁷Cl + ¹⁷⁶Yb at 170 MeV bombarding energy. The high-spin level scheme has been built from the prompt gamma rays detected using the Euroball III array. It exhibits similarities with those of the neighbouring isotopes and isotones. All the band head configurations observed in the ^97-105Tc isotopes are identified from the behaviour of the rotational bands built on them. The single-proton states located around the Fermi level are discussed as a function of deformation of these nuclei. Received: 19 January 2001 / Accepted: 23 February 2001     

Topological and dynamical excitations in a classical 2D easy-axis Heisenberg model

The properties of dynamical solitons (magnon droplets) in the classical, two-dimensional anisotropic Heisenberg model with easy-axis exchange anisotropy are studied. The solution of the Landau-Lifshitz equation in the continuum limit for the soliton with topological charge q = 1 is obtained numerically using a shooting method. We analized a wide range of the anisotropy parameter and our results are in good agreement with results obtained from spin dynamics simulations. The dependence of an internal precession frequency of the soliton on both the anisotropy parameter and the radius of the soliton is also investigated. Finally, the limits of applicability of the continuum approach are discussed. Received 22 August 2000     

Application of Thermogravimetry in the Quality Control of Chloramphenicol Tablets

The stability and thermal behaviour of chloramphenicol and various of its mixtures were investigated. The thermogravimetric and stability constant results showed that the chloramphenicol base is thermally more stable than the tablet in the studied formulation. The reduction in stability was attributed to the presence of starch in the formulation. The thermal decompositions of the chloramphenicol base and the tablet obey first-order kinetics. This revised version was published online in August 2006 with corrections to the Cover Date.     

Evaluation of thermal properties of zirconium–PHB composites

Journal of Thermal Analysis and Calorimetry - Most of the synthetic polymers that are used for packaging industry come from fossil fuel; thus, when their life cycle is complete, they normally...     

Van der Corput sets with respect to compact groups

We study the notion of van der Corput sets with respect to general compact groups.