We use the Gurvits, Kellermann, & Frey compact radio source angular size versus redshift data to place constraints on cosmological model parameters in models with and without a constant or time-variable cosmological constant. The resulting constraints are consistent with but weaker than those determined using current supernova apparent magnitude versus redshift data. Subject headings: cosmology...

in this study, alkaline colloidal silica was prepared by titration of an alkaline solution such as sodium silicate with silicic acid in constant range of ph  .this constant range of ph was achieved by using concentrated soduim silicate solutions as ph adjusting solutions during titration.the sodium silicate solutions  having a variety of concentrations were passed  through ion-exchange resin to...

this work presents thermoplastic analysis of fg rotating diskswith variable thickness and constant angular velocity. the solutions are obtained by variable material property (vmp) theory. in this theory, the domain is divided into some finite sub-domains in the radial direction, in which the properties are assumed to be constant and the form of the elastic response is used to solve elastic-plas...

Abstract The compartmental modelling is one of the most widely used techniques in investigating dynamics infectious diseases. This technique usually treats model parameters as constant. However, associated with diseases randomly change following changes conditions disease transmission. As a result, estimated are often found over or under-determined by direct problems when some and forecasting u...

stabilizations and atomic level quadrupole coupling constant (cq) properties have been investigated for graphene–like monolayers (g–monolayers) of boron nitride (bn), boron phosphide (bp), aluminum nitride (aln), and aluminum phosphide (alp) structures. to this aim, density functional theory (dft) calculations have been performed to optimize the model structures and also to evaluate the cq para...

In  this  paper a  non-linear  model  with  fractional  order  is  presented  for  analyzing  and  controlling the  spread  of  HIV virus.  Both  the  disease-free  equilibrium and the endemic equilibrium are  found  and  their  stability is  discussed. The basic reproduction number , which is a function of the constant parameters in the model, plays an essential  role in the stability of  the ...

The accelerating fields (e. g. centrifugal acceleration and constant acceleration) can change the physical performance of nano-sensors significantly. Herein, a new size-dependent model is developed to investigate the scale-dependent dynamic behavior of nanowire-fabricated sensor operated in an accelerating field. The scale-dependent equation of motion is developed by employing a consolidation o...

Background: Iodine brachytherapy sources with low photon energies have been widely used in treating cancerous tumors. Dosimetric parameters of brachytherapy sources should be determined according to AAPM TG-43U1 recommendations before clinical use. Monte Carlo codes are reliable tools in calculation of these parameters for brachytherapy sources. Materials and Methods: Dosimetric param...