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Electron beam characteristics at extended source to surface distance for a Clinac-DHX linear accelerator

100%

Arunkumar T. , Supe S. , Ravikumar M. , Sathiyan S. , Ganesh K. , Varatharaj C.

Polish Journal of Medical Physics And Engineering

2009

tom 15

nr 3

121-133

A uniform dose to the target site is required with a knowledge of delivered dose, central axis depth dose and beam flatness for successful electron treatment at an extended source to surface distance (SSD). In an extended SSD treatment under dosage of the lateral tissue may occur due to reduced beam flatness. To study the changes in beam characteristics, the depth dose curves, beam flatness and isodose distributions were measured at different SSDs from 100 to 120 cm for clinically used field sizes from (4×4) to (25×25) cm2 and beam energies ranging from 6 MeV to 20 MeV. Our results suggest that the change in depth dose is minimal except in the buildup region for most energy. In general surface dose is decreased as the SSD increased moderately. It was observed that the loss in beam flatness is significant for smaller fields, higher isodose lines, and lower energies. The penumbra enlarged and the uniformity index reduced with increasing SSD.

The influence of the injection frequency on the urea selective catalytic reduction systems performance

72%

Rogóż R. , Jaworski P. , Kapusta Ł. J. , Teodorczyk A.

Combustion Engines

2017

tom R. 56, nr 3

73--77

This study presents the influence of the UWS injection frequency on a close coupled SCR systems performance. The investigation was performed with the CFD tool AVL Fire. In the paper the analysis of four different UWS injection frequencies in the three different operating points of diesel engine was shown. The assessments of the system performance was referred to the ammonia distribution at catalyst intake and wall film formation inside the investigated geometry, as these are considered as crucial in such a configuration. The results showed that injection frequency affects both factors on different level depending from the flow conditions. In addition, the wall film crystallization risk was discussed basing on the obtained wall film characteristics.

Experimental research and CFD analysis of flow parameters in a SCR system for the original part and WALKER’s replacement

72%

Kurzydym D. , Klimanek A. , Żmudka Z.

Combustion Engines

2019

tom R. 58, nr 4

13--20

The article presents the results of experimental research and their comparison with CFD simulations for the original selective catalytic reduction system and WALKER replacement. The research was performed to develop the WALKER universal mixer. The SCR prototype without mixer and with the proposed mixer were tested and compared with the original VW part. The next step was reverse engineering, which consisted in scanning the tested parts with a laser and processing their point cloud in Leios2 program. Reverse engineering has allowed the reconstruction of 3D geometry of the tested parts in the Catia v5 program and then preparation their models for computational fluid dynamics. Numerical simulations were carried out in the Ansys Fluent program, thanks to which several quantities were determined e.g. uniformity index of gas flow through the monolith and coefficient of variation as a measure of mixing degree, which have a significant impact on the design of the mixer and the SCR system.

Ocena zmian zachodzących w zgrupowaniach roztoczy z rzędu Mesostigmata (Arachnida, Acari) w różnych stadiach sukcesji ekologicznej zwałów kopalnictwa węglowego

36%

Madej G. , Tomczok J.

Acta Biologica Silesiana

1990

tom 16

Zasiedlanie zwałowisk kopalnictwa węglowego przez roztocza z rzędu Mesostigmata (Arachnida, Acari). I. Charakterystyka zgrupowań

36%

Madej G.

Acta Biologica Silesiana

1990

tom 16