Non characteristic line harmonics of PWM AC-DC converters

2002 ◽  
Author(s):  
A.D. Graham
Keyword(s):  
Characteristic Line

An improved interference correction for trace element analysis

1992 ◽  
Vol 50 (2) ◽  
pp. 1646-1647
Author(s):  
John J. Donovan ◽  
Donald A. Snyder ◽  
Mark L. Rivers
Keyword(s):  
Trace Element Analysis ◽  
Accurate Estimate ◽  
Simple Expression ◽  
Standard Reference Materials ◽  
Characteristic Line ◽  
Analytical Line ◽  
Element Analysis ◽  
Electron Probe Analysis ◽  
Calculated Concentration ◽  
X Ray

We present a simple expression for the quantitative treatment of interference corrections in x-ray analysis. WDS electron probe analysis of standard reference materials illustrate the success of the technique.For the analytical line of wavelength λ of any element A which lies near or on any characteristic line of another element B, the observed x-ray counts at We use to denote x-ray counts excited by element i in matrix j (u=unknown; s=analytical standard; ŝ=interference standard) at the wavelength of the analytical line of A, λA (Fig. 1). Quantitative analysis of A requires an accurate estimate of These counts can be estimated from the ZAF calculated concentration of B in the unknown C,Bu measured counts at λA in an interference standard of known concentration of B (and containing no A), and ZAF correction parameters for the matrices of both the unknown and the interference standard at It can be shown that:

The Sensitivity Simulation of Different Geometric Pretreatment in Method of Characteristics

2017 ◽  
Author(s):  
Tian XiaoRui ◽  
Zhou Tao ◽  
Li Zichao ◽  
Yu Tao
Keyword(s):  
Computational Efficiency ◽  
Method Of Characteristics ◽  
Azimuthal Angle ◽  
Reactor Core ◽  
Characteristic Line ◽  
Simulation Results ◽  
And Storage

In reactor core physics analysis,the research about the pre-processing of Method of Characteristic (MOC) including the generation and storage of characteristic line,the progress of calculation and the choosing of different quadrature set.In addition,doing some simulations,which is based on OpenMOC code and C5G7-MOX benchmark,about different parameters (including the track spacing,azimuthal angles and polar angles) and calculated its impacts on the computational efficiency and accuracy.the simulation results are as following:setting the track spacing as 0.1 cm or the azimuthal angle number as 4,the simulation results have better accuracy. Whether choosing the Leonard’s optimum quadrature set or the Tabuchi-Yamamoto quadrature set,the number of polar angles have tiny impact on accuracy.

In vivo characterization of the transitional bronchioles by aerosol-derived airway morphometry

1999 ◽  
Vol 87 (3) ◽  
pp. 920-927 ◽  
Author(s):  
Kirby L. Zeman ◽  
Gerhard Scheuch ◽  
Knut Sommerer ◽  
James S. Brown ◽  
William D. Bennett
Keyword(s):  
Ex Vivo ◽  
Normal Subjects ◽  
Characteristic Line ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Lung Capacity ◽  
Single Breath ◽  
In Vivo Characterization

Effective airway dimensions (EADs) were determined in vivo by aerosol-derived airway morphometry as a function of volumetric lung depth (VLD) to identify and characterize, noninvasively, the caliber of the transitional bronchiole region of the human lung and to compare the EADs by age, gender, and disease. By logarithmically plotting EAD vs. VLD, two distinct regions of the lung emerged that were identified by characteristic line slopes. The intersection of proximal and distal segments was defined as VLDtransand associated EADtrans. In our normal subjects ( n = 20), VLDtrans [345 ± 83 (SD) ml] correlated significantly with anatomic dead space (224 ± 34 ml) and end of phase II of single-breath nitrogen washout (360 ± 53 ml). The corresponding EADtranswas 0.42 ± 0.07 mm, in agreement with other ex vivo measurements of the transitional bronchioles. VLDtrans was smaller (216 ± 64 ml) and EADtrans was larger (0.83 ± 0.04 mm) in our patients with chronic obstructive pulmonary disease ( n = 13). VLDtrans increased with age for children (age 8–18 yr; P = 0.006, n = 26) and with total lung capacity for age 8–81 yr ( P < 0.001, n = 61). This study extends the usefulness of aerosol-derived airway morphometry to in vivo measurements of the transitional bronchioles.

A Survey of Mathematical Correction Procedures in X-Ray Spectrometry

1975 ◽  
Vol 19 ◽  
pp. 1-17 ◽  
Author(s):  
Ronald Jenkins
Keyword(s):  
First Principles ◽  
Quantitative Data ◽  
Internal Standard ◽  
Characteristic Line ◽  
X Rays ◽  
Matrix Correction ◽  
Internal Standards ◽  
X Ray ◽  
Correction Equations ◽  
Secondary Fluorescence

X-ray spectrometry is an old technique dating back some sixty-odd years and although most of the early interest revolved around the qualitative aspects of the method it wasn't long before attempts were made to obtain quantitative data. One of the first recorded attempts was that by Coster and von Hevesey who in 1923 accurately determined the amount of hafnium in zirconium using tantalum as an internal standard. Glocker and Schreiber were the first to attempt calculation of X-ray characteristic line intensity from first principles although no attempt was made at that time to correct for secondary fluorescence. In von Hevesey's book, “Chemical Analysis by X-Rays,” published in 1932 , a whole chapter is devoted to what is called “Disturbing effects and their avoidance.” Among the effects discussed were primary and secondary absorbtion and third element effects. Matrix correction equations were developed although most of the quantitative work at that time was done using internal standards.

Correlation Measure-Based Stall Margin Estimation for a Single-Stage Axial Compressor

2011 ◽  
Author(s):  
Yuan Liu ◽  
Manuj Dhingra ◽  
J. V. R. Prasad
Keyword(s):  
Steady State ◽  
Axial Compressor ◽  
Operating Point ◽  
Characteristic Line ◽  
Estimation Technique ◽  
Correlation Measure ◽  
Stall Margin ◽  
Estimation System ◽  
Design Speed ◽  
Speed Characteristic

This paper presents a method for estimating compressor stall margin and the results of applying the estimation technique to an axial compressor rig. Stall margin estimation is accomplished through the use of a compressor stability detection parameter called the “correlation measure.” The correlation measure captures the periodicity of the pressure in the rotor tip region of the compressor. The downcrossing frequency of the correlation measure across some preset threshold is measured while operating the compressor rig at various steady-state points along the design speed characteristic line. These measurements are used to generate a relationship with stall margin as a function of downcrossing frequency. The estimation technique is evaluated by applying it while dynamically ramping the operating point of the compressor up the design speed line towards surge. A brief investigation on the effects of inlet distortions on the correlation measure-based estimation system is also given.

scholarly journals The Plastic Deformation of RFSSW Joints During Tensile Tests / Deformacja Plastyczna Wybranych Połączeń RFSSW Podczas Rozciągania

2015 ◽  
Vol 60 (4) ◽  
pp. 2585-2592 ◽  
Author(s):  
P. Lacki ◽  
A. Derlatka
Keyword(s):  
Plastic Deformation ◽  
Tensile Test ◽  
Numerical Models ◽  
Lap Joints ◽  
Aviation Industry ◽  
Characteristic Line ◽  
Spot Welds ◽  
Tensile Direction ◽  
Maximum Deformation ◽  
Friction Stir

The dynamic development of the friction stir welding (FSW) technology is the basis for the design of durabe joints inter alia in the aviation industry. This technology has a prospective application, especially for the aluminum alloys. It is suitable for a broad spectrum of permanent joints. The joints obtained by FSW technology are characterized by good mechanical properties. In this paper, the friction stir spot welding joints were analysed. The example of a structure made using this technology were presented. The lap joints made of 2mm Al 6061-T6 sheets were the investigation subject. The different spot welds arrangements were analysed. The tensile test were performed with optical deformation measurement system, which allow to obtain the plastic deformation field on the sample surface. The plastic strain graphs for the characteristic line passing through the maximum deformation were registered and presented. The experimental results were compared to the FEM numerical analysis. The numerical models were built with 3D-solid elements. The boundary conditions, material properties and geometry of the joints were identical as during experimental investigation. The mechanism of deformation of welded joints during tensile test was described and explained. It has been found that the arrangement of the spot welds with respect to the tensile direction has an important influence on the behaviour and deformation of lap joint.

X-Ray Tube Parameters and their Effects on Fluorescence Analysis

1963 ◽  
Vol 7 ◽  
pp. 615-622
Author(s):  
H. T. Dryer
Keyword(s):  
Target Material ◽  
Fluorescence Analysis ◽  
Design Parameters ◽  
Characteristic Line ◽  
Detector Efficiency ◽  
Tube Voltage ◽  
X Ray ◽  
Base Materials ◽  
Main Variable ◽  
Design And Manufacture

AbstractMany variables influence the performance of X-ray fluorescence analysis with regard to speed, precision, accuracy, limits of detection and the elements to be determined. Some of these variables, such as path transmittance, fluorescent yield, and detector efficiency, can be considered constant; however, the primary X-ray beam cannot be assumed a constant. The intensity distribution vs. wavelength function of the X-ray tube remains the main variable with which the X-ray spectrochemist must concern himself in providing optimum analytical performance and speed.This distribution is dependent upon target material, window material and thickness, and tube voltage. Though the overall intensity is dependent upon the atomic number of the target material, the wavelengths of the characteristic line spectrum of the target material can provide additional enhancement for elements which absorb such wavelengths readily.Some of these variables in tube design parameters have been studied to provide comparison performance data on the analysis of a variety of base materials for a number of elements of interest. These data and their interpretation are presented to show how improved fluorescence analysis can be achieved by modifications in X-ray tube design and manufacture.

Sign in / Sign up

Export Citation Format

Share Document