Spatial rainbows and catastrophes in transmission of protons through electrostatic octopole lens

This paper considers the transmission of the initial parallel proton beam with kinetic energy of 10 keV through the electrostatic oelopole lens. The spatial rainbows and corresponding proton distributions are calculated by using the infinite length approximation potential. Positive potentials of the lens electrodes are set to be 0.35 kV and 9 kV. It has been shown that by application of catastrophe theory, the generating function for mapping proton positions between entrance and exit transverse plains can be determined, giving accurate rainbow patterns for biasing potentials of 0.35 kV. © 2018; Vinca Inst Nuclear Sci. All rights reserved

The Potential of Magnesium Alloys as Bioabsorbable/ Biodegradable Implants for Biomedical Applications

The potential of magnesium alloys as bioabsorbable / biodegradable implants for biomedical applications has been extensively studied as emerging direction. This paper gives a review of current topics in this field. Research activities related to biomedical magnesium alloys have been pursued in two main directions, orthopedic and cardiovascular implants, by investigating different aspects of alloying system design, novel structures, degradation rate control, and surface modification methods. Magnesium alloys are currently considered for applications as load-bearing implant devices such as plates, screws and pins for repairing bone fracture. Highly important direction of research is degradable coronary stents. Degradable vessel stents promote stable vessel regeneration, unlike permanent stents. Different combinations of alloying elements have been investigated in order to decrease corrosion rate.Tribological issues are also important for understanding of different phenomenon related to prolongation of Mg alloys corrosion degradation time/rate, such as tribocorrosion, corrosion fatigue, and fatigue crack growth behavior

Spatial rainbows and catastrophes in transmission of protons through electrostatic octopole lens

This paper considers transmission of initial parallel proton beam with kinetic energy of 10 kеV through electrostatic octopole lens. The spatial rainbows and corresponding proton distributions are calculated by using infinite length approximation potential. Positive potentials of the lens electrodes are set to be 0.35 kV and 9 kV. It has been shown that by application of catastrophe theory, generating function for mapping proton positions between entrance and exit transverse plains can be determined, giving accurate rainbow patterns for biasing potentials of 0,35 kV. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III 45006: Physics and Chemistry with Ion Beams

Friction and Adhesion in Porous Biomaterial Structure

The paper presents short review of different aspects of the introduction of porosity into the bulk biomaterial and effects on different material characteristics, especially related to friction and adhesion. Nowadays, there is a great interest to investigate relations between porosity, different mechanical responses due to controlled topography and cell responses generated accordingly. Examples of current investigations of custom developed scaffolds for tissue engineering related to cell seeding and hip stem component are shown. Friction, adhesion and adhesive forces are briefly defined as related to porous material structures and the relevance of nano- and micro- level surface layers in such structures. Patterning techniques and micro-fabrication techniques for production of controlled and random porous surface layers are given. Influence of porosity on adhesion and friction is presented through several existing experimental results. However, there is still general lack of data related to many aspects of these novel porous materials and structures