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Your search keyword '"RAHMAN, MD. FAISAL"' showing total 5 results
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5 results on '"RAHMAN, MD. FAISAL"'

1. A Hardware/Firmware-Based Switching Gate Multiplexing Method for Pulse Mode Radiation Detectors

Author

Rahman, Md Faisal and Mattingly, John

Subjects
Physics - Instrumentation and Detectors
Abstract

We present a hardware/firmware-based switching gate multiplexing method for pulse mode radiation detectors that can combine many detector signals into two readout channels. One readout channel passes the signal of the multiplexed detector that "fired" first, and the other channel provides a variable-width logic pulse, i.e., a pulse width modulation (PWM) signal, that identifies the active detector. The multiplexed output pulse is produced by passing the first active detector's signal to a fan-in circuit by gating on the corresponding channel for a fixed duration while blocking all other detector signals. It does this using individual analog switches for all the detector signals. Each switch is controlled by a fixed width logic pulse that is triggered by the arrival of the first active detector pulse. Both the fixed width logic pulse and the PWM signal are generated using a field-programmable gate array (FPGA). To demonstrate the proposed multiplexing method, a prototype four-channel multiplexer was developed for use with four NaI(Tl) detectors. The performance of the multiplexer was evaluated in terms of its ability to retain energy resolution, timing resolution, and original pulse shape. The proposed multiplexing method showed very little degradation in energy resolution and timing resolution or alteration of pulse shape. The switching gate feature of the proposed method enables the multiplexer output to have very low noise contribution from the inactive channels. This multiplexing technique also has the unique capability of isolating and recovering the first active detector's output pulse in cases where there is overlap between pulses from different detectors in a single digitized record. These features make the proposed hardware/firmware-based switching gate multiplexing method very promising for application to large radiation detector networks., Comment: 18 pages, 27 figures

Published
2024
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4. THE ACTIVITY CONCENTRATION OF RADIONUCLIDES (226Ra, 232Th AND 40K) IN SOIL SAMPLES AND ASSOCIATED HEALTH HAZARDS IN NATORE, KUSHTIA AND PABNA DISTRICT OF BANGLADESH.

Author

EHSAN, MD. SAMIUL, RAHMAN, MD. FAISAL, TABASSUM, NAFISA, PRODHAN, MD. MAHIDUL HAQUE, PERVIN, SHIKHA, SIRAZ, M. M. MAHFUZ, RAHMAN, A. K. M. MIZANUR, YEASMIN, SELINA, and MAHAL, SYEDA FERDOUS

Subjects
*GAMMA ray spectrometry, *SOIL sampling, *NUCLEAR energy, *NUCLEAR power plants, *RADIOISOTOPES, *FUKUSHIMA Nuclear Accident, Fukushima, Japan, 2011, *HEALTH risk assessment
Abstract

The study has been carried out to measure the activity concentration of natural and anthropogenic radionuclides in fifteen(15) soil samples of Natore, Kushtia and Pabna district, which are around the 30 km peripheral area of Rooppur Nuclear Power Plant, by gamma ray spectrometry system using a High Purity Germanium (HPGe) detector. It is found that the activity concentration of 226Ra, in the collected sample was from 3.52 Bq/kg to 28.5 Bq/kg with the average value of 12.42 Bq/kg. For 232Th, the range was from 4.18 Bq/kg to 34.5 Bq/kg with the average value of 12.6 Bq/kg. Finally, the activity concentration of 40K, in the collected sample was in the range of 84 Bq/kg to 345 Bq/kg, and the average value was 198.9 Bq/kg. The absorbed dose rate (D) was found to be in the range of 4.59 nGy/h to 40.93 nGy/h with the mean value 21.3 nGy/h. The annual effective dose (E) was in the range of 0.006 mSv/yr to 0.152 mSv/yr with an average of 0.033 mSv/yr. The radium equivalent activity was in the range from 10.02 Bq/kg to 89 Bq/kg with an average of 44.99 Bq/kg. The external hazard index (Hex) was found to be in the range of 0.027 to 0.242 with the mean value of 0.121 and the internal hazard index (Hin) was found to be in the range of 0.044 to 0.302 with the mean value of 0.156. All the values are much below the recommended limit by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), 35 Bq/kg for 226Ra, 30 Bq/kg for 232Th and 400 Bq/kg for 40K. According to international and national regulation, the annual dose to members of the public, 1 mSvy-1 and Hex & Hin must be lower than unity. Moreover, no artificial radioactivity was found in the soil samples of this study area. This research concludes that the found values are within the permissible limits as required by the Nuclear Safety and Radiation Control(NSRC) Rules-1997 of Bangladesh and International Atomic Energy Agency(IAEA) Safety Standards- General Safety Requirements (GSR): Part-3. [ABSTRACT FROM AUTHOR]

Published
2019
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5. Optimizing the vertical alignment under earthwork block removal constraints in road construction

Author

Rahman, Md. Faisal

Abstract

The road design problem is usually split into the horizontal alignment, the vertical alignment, and the earthwork scheduling problems. Optimizing the vertical alignment assumes a predetermined horizontal alignment and changes the height of the road at different points to minimize overall construction costs, while maintaining the design requirements. The problem gets complicated because of the natural blocks like rivers, mountains, etc., in the road construction area. Existing vertical alignment models deal with the blocks before the beginning of road construction, which sometimes results in a non-optimal solution. A substantial portion of the total construction cost comes from the earthwork operations. As a result, some existing models only find the optimal earthwork schedule for a predetermined vertical alignment. This research extends a recent mixed integer linear programming (MILP) model that considers blocks when optimizing earthwork operations. We propose a novel model of vertical alignment that considers blocks. In the model, we propose a novel way of incorporating side-slopes of the road to improve the accuracy of the model. Our numerical results show a considerable improvement in the accuracy of the model without introducing significant computational burden. Finally, we propose another novel model using concepts from the network flow algorithms that gives more that 75% speedup for 87% of the problems for our test set of 280 problems.

Published
2012
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