Liquid and gaseous oxygen safety review

Materials used in oxygen systems and allowable oxygen environments are specified for each material. Design criteria, cleaning procedures and quality control methods are covered. Guidelines for protection against hazards involved with production, transportation, storage and use of oxygen are presented. Study also lists extensive references

Heat transfer characteristics of boiling neon and nitrogen in narrow annuli final report, apr. 1962 - sep. 1963

Heat transfer characteristics of boiling neon and nitrogen in narrow annul

Identification of nonlinear coefficient in a transport equation

Considered a problem of identification a nonlinear coefficient in a first order PDE via final observation. The problem is stated as an optimal control problem and solved numerically. Implicit finite difference scheme is used for the approximation of the state equation. A space of control variables is approximated by a sequence of finite-dimensional spaces with increaing dimensions. Finite dimensional problems are solved by a gradient method and numerical results are presented

Event-driven simulation of digital circuits using modified Petri nets algorithm

This paper presents a modified Petri nets simulation algorithm applied as an engine for a logic simulator in digital integrated circuit design. The simulator uses an event-driven algorithm and eliminates the delta delay which occurs in the majority of modern simulation algorithms. The algorithm has been tested for the logic simulation of combinational digital circuits and demonstrated more accurate simulation results. This has been achieved due to solving the issue of the priority choice problem when two or more events are occurring simultaneously

Features of the synthesis of nanocollo id oxides by laser ablation of bulk metal targets in solutions

Laser ablation of bulk targets in a fluid — a promising new method for the synthesis of "pure" nanocolloids. Nanocrystalline materials produced by laser ablation are widely used in biology, medicine, and catalysis. High local temperature during ablation and large surface area of the particles promote chemical reactions and the formation of a complex composition of nanoparticles. In this paper the characteristics of the process of ablation and the obtaining of nanoparticles in a liquid by laser ablation of active materials (Zn, Ce, Ti, Si) were studied. Ways of increasing the productivity of laser ablation were discussed. Characterization of nanocolloids and nanocrystalline powders were performed. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

Easily implementable iterative methods for variational inequalities with nonlinear diffusion-convection operator and constraints to the gradient of solution

© 2015, walter de gruyter gmbh. All rights reserved. New iterative solution methods are proposed for the finite element approximation of a class of variational inequalities with nonlinear diffusion-convection operator and constraints to the gradient of solution. Implementation of every iteration of these methods reduces to the solution of a system of linear equations and a set of two-dimensional minimization problems. Convergence is proved by the application of a general result on the convergence of the iterative methods for a nonlinear constrained saddle point problem

Iterative solution methods for variational inequalities with nonlinear main operator and constraints to gradient of solution

Convergence of the preconditioned Uzawa-type and Arrow-Hurwitz-type iterative methods for nonlinear finite dimensional constrained saddle point problems is investigated. The general results are applied to the finite element approximation of a variational inequality with nonlinear main operator and constraints to gradient of solution. © 2012 Pleiades Publishing, Ltd

Development of sers substrates based on nanoparticles obtained by pulsed laser ablation

SERS spectroscopy is an effective method for the determination of organic and biological compounds, which finds its place in many areas of human life: the analysis of works of art and food 24 YOUNG SCIENTISTS SESSION SESSION Y products, the identification of drugs and drugs, the study of biological structures, incl. at the cellular level. The creation of simple and effective SERS substrates is an urgent task in the development of this method. This paper presents the results of a study of SERS substrates based on gold nanoparticles (NPs). Gold NPs were obtained by pulsed laser ablation of an Au metal target in alcohol using a Nd:YAG laser (1064 nm, 7 ns, 150 mJ). The resulting colloidal solution was applied onto glass substrates by the drop method, varying the number of layers. The SERS characteristics were studied using a model dye rhodamine 6G using Renishaw inVia Basis Raman microscope. The samples were excited in the region of surface plasmon resonance of gold by laser radiation of 532 nm. The results of the study showed that with an increase in the number of deposited layers up to 5, the intensity of the Raman scattering of the dye increases linearly. With a further increase in the number of layers, the signal saturates. This data correlates with SEM data. At the beginning, an increase in the packing density of NPs in the plane of the substrate is observed. Accordingly, the number of "hot spots" increases, which contribute to the amplification of the signal. Further, the homogeneity of the NP layer deteriorates, and large bulk agglomerates appear. Thus, we have developed a simple method for obtaining SERS substrates, which made it possible to increase the signal intensity up to three orders of magnitude

Explicit algorithms to solve a class of state constrained parabolic optimal control problems

© 2015 by Walter de Gruyter Berlin/Boston. We consider an optimal control problem of a system governed by a linear parabolic equation with the following features: control is distributed, observation is either distributed or final, there are constraints on the state function and on its time derivative. Iterative solution methods are proposed and investigated for the finite difference approximations of these optimal control problems. Due to explicit in time approximation of the state equation and the appropriate choice of the preconditioners in the iterative methods, the implementation of all constructed methods is carried out by explicit formulae. Computational experiments confirm the theoretical results

Non-overlapping domain decomposition method for a variational inequality with gradient constraints

© Published under licence by IOP Publishing Ltd.Non-overlapping domain decomposition method is applied to a variational inequality with nonlinear diffusion-convection operator and gradient constraints. The method is based on the initial approximation of the problem and its subsequent splitting into subproblems. For the resulting constrained saddle point problem block relaxation-Uzawa iterative solution method is applied