scholarly journals Forming the Telecommunication Networks’ Cross-Sections to Analyze the Latter Stability with Different Connectivity Measures

2021 ◽  
Vol 20 (2) ◽  
pp. 371-406
Author(s):  
Aleksandr Batenkov ◽  
Kirill Batenkov ◽  
Aleksandr Fokin
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
General Concept ◽  
Telecommunication Networks ◽  
Connectivity Matrix ◽  
Sequential Search ◽  
Virtual Private Networks ◽  
Practical Applications ◽  
Telecommunications Network ◽  
Additional Procedure

The problem of stability analysis and its components of reliability and survivability is quite popular both in the field of telecommunications and in other industries involved in the development and operation of complex networks. The most suitable network model for this type of problem is a model that uses the postulates of graph theory. At the same time, the assumption of the random nature of failures of individual links of the telecommunications network allows it to be considered in the form of a generalized Erdos–Renyi model. It is well known that the probability of failure of elements can be interpreted in the form of a readiness coefficient and an operational readiness coefficient, as well as in the form of other indicators that characterize the performance of elements of a telecommunications network. Most approaches consider only the case of bipolar connectivity, when it is necessary to ensure the interaction of two end destinations. In modern telecommunications networks, services such as virtual private networks come to the fore, for which multipoint connections are organized that do not fit into the concept of bipolar connectivity. In this regard, we propose to extend this approach to the analysis of multi-pole and all-pole connections. The approach for two-pole connectivity is based on a method that uses the connectivity matrix as a basis, and, in fact, assumes a sequential search of all combinations of vertex sections, starting from the source and drain. This method leads to the inclusion of non-minimal cross-sections in the general composition, which required the introduction of an additional procedure for checking the added cross-section for non-excess. The approach for all-pole connectivity is based on a method that uses the connectivity matrix as a basis, and, in fact, assumes a sequential search of all combinations of vertex sections, not including one of the vertices considered terminal. A simpler solution was to control the added section for uniqueness. The approach for multipolar connectivity is similar to that used in the formation of the set of minimal all-pole sections and differs only in the procedure for selecting the combinations used to form the cross-section matrix, of which only those containing pole vertices are preserved. As a test communication network, the Rostelecom backbone network is used, deployed to form flows in the direction of "Europe-Asia". It is shown that multipolar sections are the most general concept with respect to two-pole and all-pole sections. despite the possibility of such a generalization, in practical applications it is advisable to consider particular cases due to their lower computational complexity.

Semi-empirical electron impact cross sections for atmospheric gases

1969 ◽  
Vol 47 (10) ◽  
pp. 1774-1777 ◽  
Author(s):  
L. R. Peterson ◽  
S. S. Prasad ◽  
A. E. S. Green
Keyword(s):  
Electron Impact ◽  
Cross Section ◽  
Cross Sections ◽  
Reference List ◽  
Atmospheric Gases ◽  
University Of Florida ◽  
Practical Applications ◽  
Functional Forms ◽  
The University ◽  
Semi Empirical

The present paper summarizes conveniently the electron-impact cross sections for N2, O2, and O used in recent aurora and dayglow studies at the University of Florida. The cross section parameters in their present form are a natural outgrowth of (a) the availability of an increasing number of cross section measurements in the laboratory as well as field observations of spectral intensities, and (b) more realistic calculations.The values presented should serve as a useful interim reference list pending the full analyses of current extensive data. Their usefulness for practical applications to problems in aeronomy is enhanced by their integrable functional forms.

scholarly journals Quantification of the Enhancement Factor in Surface-Enhanced Raman Scattering

2021 ◽  
Author(s):  
◽  
Evan Blackie
Keyword(s):  
Cross Section ◽  
Single Molecule ◽  
Cross Sections ◽  
Enhancement Factor ◽  
Density Functional ◽  
Practical Applications ◽  
Surface Enhanced Raman ◽  
Scattering Volume ◽  
Rhodamine Dye

<p>This thesis presents a rigorous stepwise methodology towards the accurate measurement and quantification of the SERS enhancement factor (EF), the key parameter in describing the SERS effect. The work represents, we believe, a successful attempt to resolve some of the inconsistencies in the literature and to refocus the field by emphasizing the importance of consistent definitions and rigorous quantification to elucidate matters of fundamental importance in SERS. The success in our approach is that it combines careful experimental measurements upon a sound theoretical framework, and utilizes a 'toolbox' of techniques developed in recent years, such as bi-analyte SERS (BiASERS) techniques for single-molecule (SM) detection, and isotopic editing. In experimental work, we measure the bare Raman cross-sections of five common probes used in SERS as a first step in measuring the analytical enhancement factor (AEF) and single-molecule enhancement factor (SMEF). The methodology in measuring these EFs involved the use of a reference standard of known cross-section along with a careful characterization of the scattering volume through beam profiling experiments. As a guide to validating the reference cross-section we make extensive use of density functional theory (DFT) calculations to obtain estimates for the intrinsic Raman cross-sections of small, non-resonant probes. The results of this work showed that previous upper limits for the EF reported in the literature of 1014 were based on a faulty normalization of the EF. In fact, EFs of 108 were sufficient to see single molecules, which is much lower than previously expected; under optimum conditions, even lower EFs, possibly down to 105 could be sufficient for the SM detection of resonant probes. As a valuable extension of BiASERS, we elaborate on the synthesis of isotopic analogues of a rhodamine dye as ideal partners for SM experiments. The synthesis and definitive characterization of these probes enable their use in an experiment to determine the SM regime in a liquid colloidal sample. Isotopically edited dyes such as these, in combination with the methodologies of EF quantification outlined herein, set the standard for those interested in accurate quantification of the SERS effect. This approach is useful in terms of both basic theoretical questions and applications such as the effective comparison of SERS substrates. Finally, we extend the techniques developed over the thesis to a long-standing and largely unresolved question in SERS: What is the minimum intrinsic Raman cross-section that can be measured as a single molecule in standard SERS conditions. In this work, we explore the SM detection non-resonant probes, which are the molecules of interest for many practical applications such as forensics and biological assays. Specifically, we demonstrate the successful SM detection of isotopically edited adenine probes.</p>

Erosion Testing and Modeling of a Triangular Elbow As Compared to a Circular Elbow

2020 ◽  
Author(s):  
Srinivas S. Kolla ◽  
Alireza Asgharpour ◽  
Siamack A. Shirazi ◽  
Gabriel Silva
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cross Section ◽  
Cross Sections ◽  
Cfd Simulation ◽  
Smooth Transition ◽  
Circular Pipe ◽  
Flow Loop ◽  
Practical Applications ◽  
Erosion Testing

Abstract The erosion patterns in elbows with circular cross-sections have been investigated extensively experimentally and computationally in the past. However, in a bid to reduce erosion in elbows, a new triangular (in cross-section) elbow has been designed and investigated comprehensively during this study. The goal of this work was to examine experimentally and predict computationally using existing erosion models, the erosion patterns in a triangular elbow geometry and compare it to circular elbows for stainless steel materials. Initially, computational fluid dynamics erosion modeling was used to compare erosion in a triangular in-cross-section elbow to a circular elbow. Computational fluid dynamics were then followed by an experimental investigation using flow visualization with a paint removal study to determine the location where particles impinge and lead to erosion. Erosion measurement experiments are also conducted in a flow loop containing liquid and 300 microns sand particles. Within the experimental rig, to avoid abrupt changes of the triangular elbow with the circular pipe, a smooth transition region is designed and utilized. Various transition geometries such as transition length, eccentricity have been investigated with CFD to ensure smooth flow and reduced erosion from the circular pipe to the triangular elbow. CFD simulation results showed that erosion also occurred on the side of the triangular elbow and have been concurred by the paint study as well. It is observed that the erosion in the triangular elbow is approximately 68% lower than that in the circular elbow for the tested conditions. Thus, it is advantageous to use these elbows for practical applications such as fracturing to reduce replacement time of elbows.

Optimization of Arrays of Rectangular Longitudinal Fins and Circular or Elliptical Cross-Section Spines

2010 ◽  
Author(s):  
P. Razelos ◽  
S. Das
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Heat Dissipation ◽  
Thermal Characteristics ◽  
Elliptical Cross Section ◽  
Elliptical Cross ◽  
Practical Applications ◽  
Pin Fins ◽  
Optimum Heat ◽  
Heat Released

The purpose of this study is to illustrate a method for obtaining the thermal performance and optimum dimensions of arrays consisting of rectangular longitudinal fins, cylindrical and elliptical cross-section spines. Since the majority of fin problems in an array have constant boundary temperatures, our endeavor is focused on the analysis and optimization of these types of fins. The temperature distribution, heat released to the environment, and the fins’ optimum dimensions in the array have been determined. Our analysis is based on a new set of dimensionless parameters, which are more suitable than those frequently used in fin analyses in the available literature. The effects of the boundary temperature ratio on the temperature variation in the fin have been examined and the results are shown graphically. Three salient results are derived regarding the thermal characteristics of these types of fins. They are: (1) the fin’s heat dissipation is expressed exactly with the same expression which describes the optimum heat dissipated by a fin with insulated tip, having half the fin’s dimensionless height. (2) The optimum fins’ dimensionless height and thickness are identical with those obtained for a fin with adiabatic tip of twice the dimensionless height (3) The optimum semi-axes ratio of elliptical-cross section spines is uniquely defined. In addition, it is shown that this approach can be successfully applied to solve problems in several practical applications, including pin fins having elliptic-cross sections. Two examples serve to illustrate the usefulness of our method.

scholarly journals Quantification of the Enhancement Factor in Surface-Enhanced Raman Scattering

2021 ◽  
Author(s):  
◽  
Evan Blackie
Keyword(s):  
Cross Section ◽  
Single Molecule ◽  
Cross Sections ◽  
Enhancement Factor ◽  
Density Functional ◽  
Practical Applications ◽  
Surface Enhanced Raman ◽  
Scattering Volume ◽  
Rhodamine Dye

<p>This thesis presents a rigorous stepwise methodology towards the accurate measurement and quantification of the SERS enhancement factor (EF), the key parameter in describing the SERS effect. The work represents, we believe, a successful attempt to resolve some of the inconsistencies in the literature and to refocus the field by emphasizing the importance of consistent definitions and rigorous quantification to elucidate matters of fundamental importance in SERS. The success in our approach is that it combines careful experimental measurements upon a sound theoretical framework, and utilizes a 'toolbox' of techniques developed in recent years, such as bi-analyte SERS (BiASERS) techniques for single-molecule (SM) detection, and isotopic editing. In experimental work, we measure the bare Raman cross-sections of five common probes used in SERS as a first step in measuring the analytical enhancement factor (AEF) and single-molecule enhancement factor (SMEF). The methodology in measuring these EFs involved the use of a reference standard of known cross-section along with a careful characterization of the scattering volume through beam profiling experiments. As a guide to validating the reference cross-section we make extensive use of density functional theory (DFT) calculations to obtain estimates for the intrinsic Raman cross-sections of small, non-resonant probes. The results of this work showed that previous upper limits for the EF reported in the literature of 1014 were based on a faulty normalization of the EF. In fact, EFs of 108 were sufficient to see single molecules, which is much lower than previously expected; under optimum conditions, even lower EFs, possibly down to 105 could be sufficient for the SM detection of resonant probes. As a valuable extension of BiASERS, we elaborate on the synthesis of isotopic analogues of a rhodamine dye as ideal partners for SM experiments. The synthesis and definitive characterization of these probes enable their use in an experiment to determine the SM regime in a liquid colloidal sample. Isotopically edited dyes such as these, in combination with the methodologies of EF quantification outlined herein, set the standard for those interested in accurate quantification of the SERS effect. This approach is useful in terms of both basic theoretical questions and applications such as the effective comparison of SERS substrates. Finally, we extend the techniques developed over the thesis to a long-standing and largely unresolved question in SERS: What is the minimum intrinsic Raman cross-section that can be measured as a single molecule in standard SERS conditions. In this work, we explore the SM detection non-resonant probes, which are the molecules of interest for many practical applications such as forensics and biological assays. Specifically, we demonstrate the successful SM detection of isotopically edited adenine probes.</p>

scholarly journals Nuclear Data Relevant to the Production of Radioiodine I-123, I-125 by Indirect Route and Medical Applications

2016 ◽  
Vol 63 ◽  
pp. 90-97
Author(s):  
Iman Tarik Al-Alawy ◽  
Raghad Saadoon Mohammed
Keyword(s):  
Cross Section ◽  
Gamma Rays ◽  
Cross Sections ◽  
Radioactive Iodine ◽  
Nuclear Data ◽  
Practical Applications ◽  
Proton Beam Energy ◽  
Exfor Library ◽  
The Cross ◽  
Indirect Route

The use of radioactive Iodine plays an important role in the treatment of some diseases and diagnosis of others, since they have suitable half-life. The radioactivity emitted from the dissolution of radioactive I-123 and I-125, such as the emission of Auger electrons, positrons and gamma rays reduce the spread of these diseases. Therefore, in this work we discuss the Iodine production via indirect reactions. In order to calculate the cross sections of these reactions for the mentioned target elements, we recommended the cross sections for EXFOR library using the recom.m program, which is written in the present work using Matlab-8, the data are taken from different authors. In order to supply accurate databases for different practical purposes such as proton beam energy monitoring, I-123 and I-125 radioisotopes production, we have evaluated the cross section collected from IAEA for EXFOR library measured by different authors of (p,xn), (d,xn) nuclear process. The selected data and our recommended cross sections were developed for practical applications. Since the preliminary overview of the cross section measurements up to 160MeV showed that there are discrepancies between the literature results.

Electron Irradiation Effects in Polyoxymethylene Crystals Grown Inside Trioxane Crystals

1971 ◽  
Vol 29 ◽  
pp. 78-79
Author(s):  
J. P. Colson ◽  
D. H. Reneker
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Detailed Examination ◽  
The Other ◽  
Electron Micrograph ◽  
Irradiation Effects ◽  
Threefold Axis ◽  
Typical Sample ◽  
Polymer Crystals ◽  
Chain Axis

Polyoxymethylene (POM) crystals grow inside trioxane crystals which have been irradiated and heated to a temperature slightly below their melting point. Figure 1 shows a low magnification electron micrograph of a group of such POM crystals. Detailed examination at higher magnification showed that three distinct types of POM crystals grew in a typical sample. The three types of POM crystals were distinguished by the direction that the polymer chain axis in each crystal made with respect to the threefold axis of the trioxane crystal. These polyoxymethylene crystals were described previously.At low magnifications the three types of polymer crystals appeared as slender rods. One type had a hexagonal cross section and the other two types had rectangular cross sections, that is, they were ribbonlike.

A quantitative approach to inner shell losses

1978 ◽  
Vol 36 (1) ◽  
pp. 526-527 ◽  
Author(s):  
R.D. Leapman ◽  
P. Rez ◽  
D.F. Mayers
Keyword(s):  
Energy Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Accurate Determination ◽  
Background Intensity ◽  
Core Excitation ◽  
Quantitative Basis ◽  
Cross Section Differential ◽  
Bound Electrons

Microanalysis by EELS has been developing rapidly and though the general form of the spectrum is now understood there is a need to put the technique on a more quantitative basis (1,2). Certain aspects important for microanalysis include: (i) accurate determination of the partial cross sections, σx(α,ΔE) for core excitation when scattering lies inside collection angle a and energy range ΔE above the edge, (ii) behavior of the background intensity due to excitation of less strongly bound electrons, necessary for extrapolation beneath the signal of interest, (iii) departures from the simple hydrogenic K-edge seen in L and M losses, effecting σx and complicating microanalysis. Such problems might be approached empirically but here we describe how computation can elucidate the spectrum shape.The inelastic cross section differential with respect to energy transfer E and momentum transfer q for electrons of energy E0 and velocity v can be written as

Oxygen K near edge structures studied with multiple scattering calculations

1988 ◽  
Vol 46 ◽  
pp. 504-505
Author(s):  
Xudong Weng ◽  
Peter Rez
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Partial Cross Section ◽  
Energy Window ◽  
Edge Structure ◽  
Fine Structures ◽  
Hydrogenic Model ◽  
Electron Energy Loss ◽  
Quantitative Chemical

In electron energy loss spectroscopy, quantitative chemical microanalysis is performed by comparison of the intensity under a specific inner shell edge with the corresponding partial cross section. There are two commonly used models for calculations of atomic partial cross sections, the hydrogenic model and the Hartree-Slater model. Partial cross sections could also be measured from standards of known compositions. These partial cross sections are complicated by variations in the edge shapes, such as the near edge structure (ELNES) and extended fine structures (ELEXFS). The role of these solid state effects in the partial cross sections, and the transferability of the partial cross sections from material to material, has yet to be fully explored. In this work, we consider the oxygen K edge in several oxides as oxygen is present in many materials. Since the energy window of interest is in the range of 20-100 eV, we limit ourselves to the near edge structures.

Absolute inner-shell cross section determination for EELS analysis

1988 ◽  
Vol 46 ◽  
pp. 534-535
Author(s):  
P.A. Crozier
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Absolute Cross Section ◽  
Specimen Thickness ◽  
Mass Thickness ◽  
Scattering Cross ◽  
Before And After ◽  
Estimated Error ◽  
Scattering Cross Sections ◽  
Electron Microscopist

Absolute inelastic scattering cross sections or mean free paths are often used in EELS analysis for determining elemental concentrations and specimen thickness. In most instances, theoretical values must be used because there have been few attempts to determine experimental scattering cross sections from solids under the conditions of interest to electron microscopist. In addition to providing data for spectral quantitation, absolute cross section measurements yields useful information on many of the approximations which are frequently involved in EELS analysis procedures. In this paper, experimental cross sections are presented for some inner-shell edges of Al, Cu, Ag and Au.Uniform thin films of the previously mentioned materials were prepared by vacuum evaporation onto microscope cover slips. The cover slips were weighed before and after evaporation to determine the mass thickness of the films. The estimated error in this method of determining mass thickness was ±7 x 107g/cm2. The films were floated off in water and mounted on Cu grids.

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