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Determination of Optimum Material and Thickness of Filter Based on Radiation Energy in Digital Industrial Radiography (CR) Using MCNP Monte Carlo Simulation Code
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Naser (Supervisor) ; Rokrok, Behrouz (Supervisor) ; Movafeghi, Amir (Co-Supervisor)
Abstract
In this study, the effect of external filter on the various parameters of image quality in digital industrial radiography by CR method for steel and aluminum piece has been investigated. The filter reduces the noise of scattered beams by absorbing the low-energy beams in the X-ray spectrum that are most likely to be scattered, but high filter thicknesses can attenuate the more energetic beams and have a negatively effect on the image quality. On the other hand, the absorption of those low-energy beams increases the average spectrum energy and thus reduce the contrast, so it is necessary to use the appropriate material and thickness of the filter. For this purpose, to examine the filter...
A reconfigurable fault-tolerant routing algorithm to optimize the network-on-chip performance and latency in presence of intermittent and permanent faults
, Article Proceedings - IEEE International Conference on Computer Design: VLSI in Computers and Processors ; 2011 , Pages 433-434 ; 10636404 (ISSN) ; 9781457719523 (ISBN) ; Modarressi, M ; Sarbazi Azad, H ; Sharif University of Technology
2011
Abstract
As the semiconductor industry advances to the deep sub-micron and nano technology points, the on-chip components are more prone to the defects during manufacturing and faults during system operation. Consequently, fault tolerant techniques are essential to improve the yield of modern complex chips. We propose a fault-tolerant routing algorithm that keeps the negative effect of faulty components on the NoC power and performance as low as possible. Targeting intermittent faults, we achieve fault tolerance by employing a simple and fast mechanism composed of two processes: NoC monitoring and route adaption. Experimental results show the effectiveness of the proposed technique, in that it offers...
Dynamic Modeling and Congestion Control in Computer Networks
, M.Sc. Thesis Sharif University of Technology ; Jahangir, Amir Hossein (Supervisor) ; Ebrahim, Behrouz (Co-Advisor)
Abstract
Active queue management (AQM) is a key factor in congestion control and should provide appropriate feedback for flow control in traffic sources to overcome the congestion problem. Beside providing congestion control, achieving predictable queuing delay, maximizing link utilization, simplicity and robustness are also the main objectives of an AQM controller. We propose in this thesis an improved queue dynamic model while incorporating the packet drop probability as well. The proposed model is evaluated using ns2 platform. By applying the improved model, a new compensated proportionalintegral- derivative (PID) AQM controller is developed for TCP network. The time-varying nature of the network...
Recovery of Uranium(VI) from UCF Waste by Selective Transportacross Aliquid Membrane
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor) ; Fasihi, Javad (Supervisor)
Abstract
Due to environmental and economical impacts, recovery of the uranium from nuclear wastes is of continuing interest.This work reports the separation of uranyl ionusing transport technique through chloroform liquid membrane containing a mixture of DBDA15C4 and oleic acidas cooperative carrier.The pH of the feed phase (10-4 M of UO22+) was adjusted with nitric acid and acetic acid/NaOH for pHrange of 2-6.The receiving phase was hydrochloric acid 1M.The organic phase was chloroform which includesthe carrier DBDA15C4 (0.0001 M) and also the oleic acid (0.015M).The results showed that the transport increased with increasing pH and reached to maximumat pH of 5.Maximum cooperative effect of oleic...
A radiographic calibration method for eddy current testing of heat exchanger tubes
, Article Insight: Non-Destructive Testing and Condition Monitoring ; Volume 46, Issue 10 , 2004 , Pages 594-597 ; 13542575 (ISSN) ; Kargarnovin, M. H ; Soltanianzadeh, H ; Edalati, K ; Rokrok, B ; Kermani, A ; Seidi, M ; Sharif University of Technology
2004
Abstract
The most technically available NDT method for in-service inspection of heat exchanger tubes is eddy current testing. Using a differential ID bobbin probe, tubes can be tested with high speed, but for accurate estimation of tube condition, precisely machined calibration blocks from the same material are necessary. The purpose of this work was to calibrate the eddy current system by radiography without the use of expensive calibration blocks. Wall thickness measurement and deterioration determination due to corrosion/erosion/pitting was evaluated in this study by using radiograph ie film density measurements. It was found that this method can determine the remaining wall thickness as well as...
Flaw detection improvement of digitised radiographs by morphological transformations
, Article Insight: Non-Destructive Testing and Condition Monitoring ; Volume 47, Issue 10 , 2005 , Pages 625-630 ; 13542575 (ISSN) ; Kargarnovin, M. H ; Soltanian Zadeh, H ; Taheri, M ; Ghasemi, F ; Rokrok, B ; Edalati, K ; Rastkhah, N ; Sharif University of Technology
2005
Abstract
Radiographic inspection is one of the most appreciated techniques among non-destructive testing methods due to the production of a film which acts as a unique fingerprint record. Converting radiographs to a digital format and further digital image processing is the best method of enhancing the image quality and assisting the interpreter on his evaluation. In this research, different algorithms were used for image enhancement and radiograph interpretation in MATLAB environment. A graphical user interface (GUI) was created for implementation of different algorithms. Both spatial and frequency domains techniques were used for image enhancement. The main enhancement technique was a spatial...
Quality improvement of digitized radiographs by filtering technique development based on morphological transformations
, Article 2004 Nuclear Science Symposium, Medical Imaging Conference, Symposium on Nuclear Power Systems and the 14th International Workshop on Room Temperature Semiconductor X- and Gamma- Ray Detectors, Rome, 16 October 2004 through 22 October 2004 ; Volume 3 , 2004 , Pages 1845-1849 ; 10957863 (ISSN) ; Taheri, M ; Kargarnovin, M. H ; Ghasemi, F ; Rokrok, B ; Seiedi, M ; Edaalati, K ; Kermani, A ; Rastkhah, N ; Sharif University of Technology
2004
Abstract
Radiographic inspection is the most appreciated technique among the other non-destructive testing methods due to producing unique finger print record as the film. Converting of radiographs to a digital format and further digital image processing is the best method of enhancing the image quality and assisting the interpreter on his evaluation. In this research, different algorithms were used for image enhancement and radiograph interpretation in MATLAB environment. A graphical user interface (GUI) was created for implementation of different algorithms. Both spatial and frequency (wavelet) domains techniques were used for image enhancement. Results showed that the defect recognition...