Four different orthodontic applications of a polyethylene fiber material are shown and discussed in case reports. Ribbond (Ribbond Inc, Seattle, Wash), a bondable, reinforced polyethylene fiber material, was successfully used in a fixed orthodontic retainer, a space maintainer, a temporary postorthodontic fixation device to attach a pontic to abutment teeth during periodontal therapy, and a pos...

Two different local-density approximations, the Gáspár-Kohn-Sham and the Perdew-Zunger approximations, of the density-functional method have been used to calculate structural and electronic properties of polyethylene systems with several different dihedral angles. For each system, the CC bond lengths and the CCC and HCH bond angles are optimized simultaneously. All the parameters appear to be s...

Introduction: In contemporary THA there are two broad approaches to acetabular cup design and materials. One is an all-polyethylene design with polymethylmethacrylate (PMMA) cement. PMMA possesses a modulus of elasticity of about 2 GPa, which is between that of trabecular and subchondral bone. The second more popular approach, especially for active, younger patients, is the porous metal-backed ...

Polyethylene oxide –b– polypropylene oxide -bpolyethylene oxide (EO106PO70EO106) block copolymer self-organizes into polymeric supramolecules, characterized by NMR as phase transition from the isotropic stack-up block structure to the ordered cubic polymeric supramolecular structure. Its dependence on both temperature and copolymer concentration is clearly shown by the changes in line shape and...

cuals2  chalcopyrite  nanocrystalline  are  synthesized  with  facile method.  the  heat  arrested  solvothermal  method  for  synthesize nanocrystalline  were  investigated.  the  time  duration  of  synthesis, temperature of solution and metal salts to solvent molar ratio can be parameters  that we are  studied. the nanoparticles were  synthesized with cucl, alcl3 and  thiourea (sc(nh2)2) as ...

background: polyethylene composites including boron can be used as an effective neutron shield. our investigation focuses on manufacturing borated polyethylene nano-composite. the purpose of this study is to design a radiation shield for use in both neutron and gamma fields. materials and methods: borated polyethylene shields containing 2%, and 5% weight percentage of boron nano-particles were ...

Density functional theory (DFT) calculations are performed to find the structural parameters of orthorhombic polyethylene crystal. Computations are carried using Plain wave self-consistent field method implemented in the PWscf software and various pseudo-potentials are used. The calculated values of geometrical parameters are in good agreement with reported values, but the cohesive energy show ...

In order to increase our fundamental knowledge about high-voltage cable insulation materials, realistic polyethylene (PE) structures, generated with a novel molecular modeling strategy, have been analyzed using first principle electronic structure simulations. The PE structures were constructed by first generating atomistic PE configurations with an off-lattice Monte Carlo method and then equil...

This paper discusses two common problems, “weld tenting” and low coating thickness over the external weld, and their causes in traditional three layer polyolefin pipeline coatings. To tackle these problems, a new approach to applying multilayer polyolefin coating to pipes is introduced. The new system consists of side-extruding high density polyethylene over a graded structure polyethylene (GSP...