Kinetic phenomena in transport of electrons and positrons in gases caused by the properties of scattering cross sections

Collisions of electrons, atoms, molecules, photons and ions are the basic processes in plasmas and ionized gases in general. This is especially valid for low temperature collisional plasmas. Kinetic phenomena in transport are very sensitivitive to the shape of the cross sections and may at the same time affect the macroscopic applications. We will show how transport theory or simulation codes, phenomenology, kinetic phenomena and transport data may be used to improve our knowledge of the cross sections, our understanding of the plasma models, application of the swarm physics in ionized gases and similar applications to model and improve gas filled traps of positrons. Swarm techniques could also be a starting point in applying atomic and molecular data in models of electron or positron therapy/diagnostics in radiation related medicine

Transarterial chemoembolisation (TACE) using irinotecan-loaded beads for the treatment of unresectable metastases to the liver in patients with colorectal cancer: an interim report

<p>Abstract</p> <p>Background</p> <p>Following failure of standard systemic chemotherapy, the role of hepatic transarterial therapy for colorectal hepatic metastasis continues to evolve as the experience with this technique matures. The aim of this study to gain a better understanding of the value of drug eluting bead therapy when administered to patients with unresectable colorectal hepatic metastasis.</p> <p>Methods</p> <p>This was an open-label, multi-center, single arm study, of unresectable colorectal hepatic metastasis patients who had failed standard therapy from 10/2006-10/2008. Patients received repeat embolizations with Irinotecan loaded beads(max 100 mg per embolization) per treating physician's discretion.</p> <p>Results</p> <p>Fifty-five patients underwent 99 treatments using Irinotecan drug eluting beads. The median number of total treatments per patient was 2(range of 1-5). Median length of hospital stay was 23 hours(range 23 hours - 10 days). There were 30(30%) sessions associated with adverse reactions during or after the treatment. The median disease free and overall survival from the time of first treatment was 247 days and 343 days. Six patients(10%) were downstaged from their original disease status. Of these, four were treated with surgery and two with RFA.</p> <p>Neither number of liver lesions, size of liver lesions or extent of liver replacement(<= 25% vs >25%) were predictors of overall survival. Only the presence of extrahepatic disease(p = 0,001), extent of prior chemotherapy (failed 1^stand 2^ndline vs > 2 line failure)(p = 0,007) were predictors of overall survival in multivariate analysis.</p> <p>Conclusion</p> <p>Chemoembolization using Irinotecan loaded beads was safe and effective in the treatment of patients as demonstrated by a minimal complication rate and acceptable tumor response.</p

Potential applications of nanometerials in the aviation industry: a review; International Conference of Experimental and Numerical Investigations and NewTechnologies

J. Bosnjakovic, D. Pavlovic, I. Vasovic Maksimovic; Potential applications of nanometerials in the aviation industry: a review; International Conference of Experimental and Numerical Investigations and NewTechnologies; Zlatibor, Serbia, 29 Jun- 02 July 2021; Serbia; The book of Abstracts; ISBN: 978-86-6060-077-8; pp. 98; 2021

Third-order transport coefficient tensor of charged-particle swarms in electric and magnetic fields

Third-order transport coefficient tensor of charged-particle swarms in neutral gases in the presence of spatially uniform electric and magnetic fields is considered using a multiterm solution of Boltzmann's equation and Monte Carlo simulation technique. The structure of the third-order transport coefficient tensor and symmetries along its individual components in varying configurations of electric and magnetic fields are addressed using a group projector technique and through symmetry considerations of the Boltzmann equation. In addition, we focus upon the physical interpretation of the third-order transport coefficient tensor by considering the extended diffusion equation which incorporates the contribution of the third-order transport coefficients to the density profile of charged particles. Numerical calculations are carried out for electron and ion swarms for a range of model gases with the aim of establishing accurate benchmarks for third-order transport coefficients. The effects of ion to neutral-particle mass ratio are also examined. The errors of the two-term approximation for solving the Boltzmann equation and limitations of previous treatments of the high-order charged-particle transport properties are also highlighted

Electron transport and negative streamers in liquid xenon

In this work we investigate electron transport, transition from an electron avalanche into a negative streamer, and propagation of negative streamers in liquid xenon. Our standard Monte Carlo code, initially developed for dilute neutral gases, is generalized and extended to consider the transport processes of electrons in liquids by accounting for the coherent and other liquid scattering effects. The code is validated through a series of benchmark calculations for the Percus-Yevick model, and the results of the simulations agree very well with those predicted by a multi term solution of Boltzmann's equation and other Monte Carlo simulations. Electron transport coefficients, including mean energy, drift velocity, diffusion tensor, and the first Townsend coefficient, are calculated for liquid xenon and compared to the available measurements. It is found that our Monte Carlo method reproduces both the experimental and theoretical drift velocities and characteristic energies very well. In particular, we discuss the occurrence of negative differential conductivity in the E/n(o) profile of the drift velocity by considering the spatially-resolved swarm data and energy distribution functions. Calculated transport coefficients are then used as an input in fluid simulations of negative streamers, which are realized in a 1.5 dimensional setup. Various scenarios of representing the inelastic energy losses in liquid xenon, ranging from the case where the energy losses to electronic excitations are neglected, to the case where some particular excitations are taken into account, and to the case where all electronic excitations are included, are discussed in light of the available spectroscopy and photoconductivity experiments. We focus on the way in which electron transport coefficients and streamer properties are influenced by representation of the inelastic energy losses, highlighting the need for the correct representation of the elementary scattering processes in the modeling of liquid discharges