scholarly journals Diffusion synthetic acceleration with the fine mesh rebalance of the subcell balance method with tetrahedral meshes for SN transport calculations

2020 ◽  
Vol 52 (3) ◽  
pp. 485-498
Author(s):  
Habib Muhammad ◽  
Ser Gi Hong
Author(s):  
Steve A. Maas ◽  
Benjamin J. Ellis ◽  
David S. Rawlins ◽  
Jeffrey A. Weiss

Tetrahedral elements are one of the most popular finite element (FE) modeling primitives for complex, biological geometries, partially due to the availability of automatic meshing schemes for creating tetrahedral meshes. However, constant strain tetrahedral elements require a very fine mesh to obtain accurate solutions, and these elements can lock, yielding overly stiff results [1].


Author(s):  
Neng-Bo He ◽  
S.W. Hui

Monolayers and planar "black" lipid membranes have been widely used as models for studying the structure and properties of biological membranes. Because of the lack of a suitable method to prepare these membranes for electron microscopic observation, their ultrastructure is so far not well understood. A method of forming molecular bilayers over the holes of fine mesh grids was developed by Hui et al. to study hydrated and unsupported lipid bilayers by electron diffraction, and to image phase separated domains by diffraction contrast. We now adapted the method of Pattus et al. of spreading biological membranes vesicles on the air-water interfaces to reconstitute biological membranes into unsupported planar films for electron microscopic study. hemoglobin-free human erythrocyte membrane stroma was prepared by hemolysis. The membranes were spreaded at 20°C on balanced salt solution in a Langmuir trough until a surface pressure of 20 dyne/cm was reached. The surface film was repeatedly washed by passing to adjacent troughs over shallow partitions (fig. 1).


Author(s):  
B. Lencova ◽  
G. Wisselink

Recent progress in computer technology enables the calculation of lens fields and focal properties on commonly available computers such as IBM ATs. If we add to this the use of graphics, we greatly increase the applicability of design programs for electron lenses. Most programs for field computation are based on the finite element method (FEM). They are written in Fortran 77, so that they are easily transferred from PCs to larger machines.The design process has recently been made significantly more user friendly by adding input programs written in Turbo Pascal, which allows a flexible implementation of computer graphics. The input programs have not only menu driven input and modification of numerical data, but also graphics editing of the data. The input programs create files which are subsequently read by the Fortran programs. From the main menu of our magnetic lens design program, further options are chosen by using function keys or numbers. Some options (lens initialization and setting, fine mesh, current densities, etc.) open other menus where computation parameters can be set or numerical data can be entered with the help of a simple line editor. The "draw lens" option enables graphical editing of the mesh - see fig. I. The geometry of the electron lens is specified in terms of coordinates and indices of a coarse quadrilateral mesh. In this mesh, the fine mesh with smoothly changing step size is calculated by an automeshing procedure. The options shown in fig. 1 allow modification of the number of coarse mesh lines, change of coordinates of mesh points or lines, and specification of lens parts. Interactive and graphical modification of the fine mesh can be called from the fine mesh menu. Finally, the lens computation can be called. Our FEM program allows up to 8000 mesh points on an AT computer. Another menu allows the display of computed results stored in output files and graphical display of axial flux density, flux density in magnetic parts, and the flux lines in magnetic lenses - see fig. 2. A series of several lens excitations with user specified or default magnetization curves can be calculated and displayed in one session.


Author(s):  
Е. А. Фролов ◽  
В. В. Агарков ◽  
С. И. Кравченко ◽  
С. Г. Ясько

To determine the accuracy of the readjustable punches for separating operations (perforation + punching out) of sheet-metal forming, the accuracy parameters were analyzed using the random balance method using the method of experiment planning. Analytical dependencies are obtained to determine the values of deviation of the outer and inner contour dimensions of perforated and punched out sheet parts. From the dependencies obtained, it is possible to estimate and predict the value of deviation in the dimensions of the resulting part at any time during the operation of the punch. Practical recommendations on the calculation of the actuating dimensions of the working elements (stamping punch, matrix) of readjustable punches are offered.


2020 ◽  
Vol 23 (12) ◽  
pp. 1356-1382
Author(s):  
E.V. Olomskaya ◽  
A.A. Aksent'ev

Subject. This article discusses the methodological features of Russian Accounting Standard (PBU) 18/02 Income Tax Accounting when using the balance method to account for deferred taxes. It considers whether the clarification of permanent tax differences is justified, and it analyzes in detail the features of accounting for temporary differences and offers a visual and descriptive method for determining and correlating them in accounts. Objectives. The article aims to justify the reason for linking permanent tax differences to such accounting categories as Income and Expenses. It also aims to develop a methodological toolkit that simplifies the perception of the balance method and demonstrates the procedure for determining temporary differences. Methods. For the study, we used the methods of analysis, synthesis, observation, comparison, and other general scientific methods. Results. The article justifies the clarification of permanent differences from the position of accounting categories. It offers an original approach that helps visually classify temporary differences. The formalization of the balance method helped identify the logic of its reflection in accounting statements. Conclusions and Relevance. To ensure that accounting is not distorted due to the impact of taxation, it is necessary to develop a unified conceptual framework, as well as develop existing methods and introduce new ones that do not contradict the public concept of interaction between accounting and tax accounting. The research results are intended for training, scientific and practical activities of specialists in the field of accounting and audit, as well as students studying under this program, in order to study the features of applying the balance method for accounting for deferred taxes.


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