Search results for "Peek"
showing 10 items of 25 documents
Behavior of polyether-ether-ketone (PEEK) in prostheses on dental implants. A review.
2020
Background The development of new and innovative materials such as high performance polymers (PEEK) opens a wide therapeutic range in implant prostheses. They are presented as alternative materials to metal and zirconium alloys in the manufacture of structures and attachments for implant prostheses and fixed and removable dental substitutes. The objective of this review is to know the characteristics of this material and thus assess its advantages and disadvantages in its possible applications in prostheses on dental implants. Material and methods A bibliographic search was carried out through the PubMed and Scopus search engines, of articles published from 2007 to 2020, excluding all artic…
ZrO2 nanodaļiņu zeta potenciāls un izmēru sadalījums dažādas koncentrācijas H3PO4 un ZrO2 ūdens šķīdumos
2018
ZrO 2 nanodaļiņu zeta potenciāls un izmēru sadalījums dažādas koncentrācijas h 3 po 4 un zro 2 ūdens šķīdumos. Novikovs A., zinātniskais vadītājs Dr. habil. phys. G. Vaivars, Maģistra darbs, 152 lappuses, 73 attēli, 58 tabulas, 67 literatūras avoti. Latviešu valodā. Šajā darbā tika pagatavoti vairāki ZrO 2 un H 3 PO 4 , ZrO 2 un SPEEK polimēra šķīdumi un raksturoti ar dinamiskās un elektroforētiskās gaismas izkliedes metodēm. Tika apskatīta literatūra par DLS un ELS darbības principiem, iegūstamo lielumu dabu un faktoriem, kuri ietekmē uz elektriski stabilizētas dispersijas viendabīguma saglabāšanos laikā un citām plaši lietojamām metodēm ZrO 2 ūdens dispersiju raksturošanai.
Development of new centrifuges for fast solvent extraction of transactinide elements
1995
The H-0.3 liquid-liquid centrifuge applied for rapid and efficient separation of two liquid phases, and the HG-0.1 gas-liquid centrifuge used to separate the gas phase stemming from a gas jet transportation system and the liquid phase, have been further improved. New centrifuges have been produced of PEEK, a plastic material, which makes them resistant to most aqueous and organic solutions. The performance with respect to time behavior and phase purity is comparable to the titanium centrifuges used so far. The H-0.3 centrifuge has been applied to solvent extraction studies of Zr, Nb, Mo, Hf, Ta, W and Pa from HF solutions into tri-n-octylamine.
Flow phenomenon of micron-sized particles during cold spray additive manufacturing: High-speed optic observation and characterization
2020
Abstract A high-speed laser shadowgraph observation of the particles flow during cold spraying enables a good phenomenological characterization. The particles in-flight behaviour develops a kinematics with two regimes regardless the powder nature. When leaving the nozzle, the particles form a regime of uniform jet over a certain distance along the flow direction, and then a regime of sparse jet while particles deviate in the radial direction. This dispersion increases away from the nozzle exit and exhibits thereby an event of oblique collision during an additive route process. Under such conditions, kinematic deficiency prevails since oblique collision has shown to alter the deposition effi…
Mechanical behavior of provisional implant prosthetic abutments
2014
Introduction: Implant-supported prostheses have to overcome a major difficulty presented by the morphology and esthetics of peri-implant tissues in the anterior sector. Diverse therapeutic techniques are used for managing the mucosa adjacent to the implant and the most noteworthy is immediate/deferred fixed provisionalization. Objectives: In vitro testing of strength and deformation of implant prosthetic abutments made from different materials (Titanium/PEEK/methacrylate). Material and Methods: Forty Sweden&Martina® implant prosthetic abutments (n=40) were divided into five groups: Group MP: methacrylate provisional abutments with machined titanium base; Group PP: Poly ether ether ketone (P…
High Voltage Insulation and Gas Absorption of Polymers in High Pressure Argon and Xenon Gases
2018
High pressure gas time projection chambers (HPGTPCs) are made with a variety of materials, many of which have not been well characterized in high pressure noble gas environments. As HPGTPCs are scaled up in size toward ton-scale detectors, assemblies become larger and more complex, creating a need for detailed understanding of how structural supports and high voltage insulators behave. This includes the identification of materials with predictable mechanical properties and without surface charge accumulation that may lead to field deformation or sparking. This paper explores the mechanical and electrical effects of high pressure gas environments on insulating polymers PTFE, HDPE, PEEK, POM …
Improvement of flame spraying PEEK coating characteristics using lasers
2011
Flame spraying is frequently used for PEEK coatings elaboration on metallic surfaces. However, this process has a certain number of limitations particularly considering the quality of the coatings like high porosity or low interfacial adherence. For that reason a thermal post-processing is often necessary. From all of the processes which can be used (flame, oven, etc.), laser can be an interesting technology. Then, the aim of this study is to analyse the dependence of the morphological structure (compactness) and the adherence of the flame sprayed PEEK coatings to the stainless steel (304L) and aluminium alloy (AA2017) substrates on laser parameters. Moreover, the influence of the laser bea…
Laser densification of organic coating: Effects of laser wavelength, operating parameters and substrate properties
2012
International audience; Mechanical bonding and interface behaviour play a key role for any materials deposited on different substrates. Usually, a post-spray heat treatment is required to improve the coating morphology and to enhance mechanical properties of thermal-sprayed polymeric coating. The effects of YAG, CO2 and diode laser radiations on as-sprayed PEEK coating deposited on stainless steel and aluminum substrates were investigated. The results revealed a good coating densification and interface behavior. A correlation between coating and substrate absorption coefficients, their thermophysical properties and laser operating parameters was shown. Besides, the finite element modeling b…
Glassy PEEK‐WC vs Rubbery Pebax®1657 Polymers: Effect on the Gas Transport in CuNi‐MOF Based Mixed Matrix Membranes
2020
Mixed matrix membranes (MMMs) are seen as promising candidates to overcome the fundamental limit of polymeric membranes, known as the so-called Robeson upper bound, which defines the best compromise between permeability and selectivity of neat polymeric membranes. To overcome this limit, the permeability of the filler particles in the MMM must be carefully matched with that of the polymer matrix. The present work shows that it is not sufficient to match only the permeability of the polymer and the dispersed phase, but that one should consider also the individual contributions of the diffusivity and the solubility of the gas in both components. Here we compare the gas transport performance o…
A first peek into sub-picosecond dynamics of spin energy levels in magnetic biomolecules
2019
We estimate the time- and temperature-evolution of spin energy levels in a metallopeptide by combining molecular dynamics with crystal field analysis. Fluctuations of tens of cm-1 for spin energy levels at fs times gradually average out at longer times. We confirm that local vibrations are key in spin dynamics.