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Papers by ali negarestani

Nuclear and Particle Physics Proceedings, Oct 31, 2023

فصلنامه علمی علوم زمین, Nov 22, 2010

7KH FODVWLF IDFLHV RI .DKDU)RUPDWLRQ ZHUH LGHQWL¿HG LQ WKH VWXGLHG VHFWLRQV RI FRDVWDO GHOWDLF DQ... more 7KH FODVWLF IDFLHV RI .DKDU)RUPDWLRQ ZHUH LGHQWL¿HG LQ WKH VWXGLHG VHFWLRQV RI FRDVWDO GHOWDLF DQG ÀXYLDO DQG DOVR FDUERQDWH IDFLHV LQ VKDOORZ PDULQH environments. The vertical displacements of Kahar Formation in these study sections show an overall major transgressive upward cycle. The petrography of plutonic and semi-plutonic igneous rocks indicate that they consist mainly of monzogabbro-diorite and in some cases, alkaline syenite. According to the results of Kahar Formation's plutonic rocks petrography and studies of related facies, the basin of this formation was a continental rift.

Iranian Journal of Radiation Safety and Measurement, Jun 10, 2018

Iranian Journal of Radiation Safety and Measurement, Sep 10, 2013

Journal of Instrumentation, Dec 10, 2019

Radiation Protection Dosimetry, Oct 25, 2019

In this study, a new model based on electric circuit theory has been introduced to simulate the d... more In this study, a new model based on electric circuit theory has been introduced to simulate the dynamics of radioactive chemically inert gases in the human body. For this manner, it is assumed that inert gas is transported through the body to various organs via the blood stream. In this simulation, a voltage source is equivalent to gas generation in the atmosphere, the conductivity is equivalent to the cardiac output of the organ, the capacitor capacitance is equivalent to the volume of blood or tissue and voltage across a capacitor is equivalent to the gas concentration in air or blood or a tissue. This simulation can be used to study the dynamics of any inert gas whose partition coefficients are known. We use this simulation to study the dynamics of radon in human body. The physiologically based pharmacokinetic (PBPK) model that describes the fate of radon in systemic tissue has been used for this simulation. Using this simulation, the effective dose equivalent resulting from inhalation of radon has been estimated. The calculated values agree with the previously reported value. Also, using the model, it has been shown that after inhalation of radon gas, absorbed dose has been decreased in different tissues by increasing the inhalation rate without radon. So that, by doubling the inhalation rate and the rate of cardiac output, the value of the absorbed dose has been decreased 11.88% in the adipose tissue, 25.49% in the red marrow tissue and 20.3% in the liver organ.

Journal of Environmental Radioactivity, 2002

A layered neural network (LNN) has been employed to estimate the radon concentration in soil rela... more A layered neural network (LNN) has been employed to estimate the radon concentration in soil related to the environmental parameters. This technique can find any functional relationship between the radon concentration and the environmental parameters. Analysis of the data obtained from a site in Thailand indicates that this approach is able to differentiate time variation of radon concentration caused by environmental parameters from those arising by anomaly phenomena in the earth (e.g. earthquake). This method is compared with a linear computational technique based on impulse responses from multivariable time series. It is indicated that the proposed method can give a better estimation of radon variations related to environmental parameters that may have a non-linear effect on the radon concentration in soil, such as rainfall.

Asian Journal of Water, Environment and Pollution, May 11, 2018

Geno hot spring is one of the famous hot springs and hydrotherapy centers in Iran which has been ... more Geno hot spring is one of the famous hot springs and hydrotherapy centers in Iran which has been used since ancient times. The spring is located on the eastern edge of anticline of double plunges of Geno from the series of Zagros folded corrosion. The average water temperature in Geno hot spring is 41/22 ° C and releases a strong odor of hydrogen sulfide due to sulfate rduction. The water type is sodium chloride (Na-Cl) due to the outcrop of salt domes of Hormuz Series, possible flow of water at great depth and flows back to the surface. The water is in a relative maturity and has reached a rather equilibrium with its rock repository. Weak correlation between magnesium and chloride ions in the samples of Geno hot spring can be the result of mixing of surface waters with deep brine. The water is saturated toward aragonite, calcite and dolomite and is under saturated toward phases such as gypsum, halite and anhydrite. Water temperature in the reservoir of Geno hot spring is estimated to be 55 to 154 0 C based on geothermometer surveys. Radon concentration in water of Geno varies between 17.75 and 46.30 kBq/m3 throughout the year, so this spring is not a radon hot spring.

Nuclear Instruments and Methods in Physics Research, Mar 1, 2018

Addressed herein, a new monitoring method for alpha surface contamination based on the function o... more Addressed herein, a new monitoring method for alpha surface contamination based on the function of a thick gaseous electron multiplier (THGEM) in a self-quenching streamer mode (SQS) has been introduced. SQS mode detectors can detect alpha surface contamination in two dimensions. In the current study, the ability of thick gas electron multiplier detectors in SQS mode for two-dimensional monitoring of alpha surface contamination has been investigated by two Am-241 sources with activities equal to 33 and 150 kBq.m-3. It has been found that the brightness is stronger in front of stronger sources. This may be attributed to the difference in contamination levels. It was also observed that the spatial resolution of the contamination rate depends on the number of holes per unit area of each THGEM. The advantage of this system is the ability to determine both the location and intensity of surface contamination with no need for an electronic multiplier or reader system.

journal of sciences islamic republic of iran, 2014

The presence of radon in drinking water causes health risks associated with exposure from both in... more The presence of radon in drinking water causes health risks associated with exposure from both inhalation and ingestion. Since the studies show that faults near the water resources have a critical effect on the concentration of radon, Kouhbanan active fault zone, to find water resources with high radon concentration was chosen for the following investigation. Water samples were taken from all of the 39 drinking water springs and Qanats in the Kouhbanan region, both in the summer and winter. Its length is 280Km and is aligned from Bahabad city in north-west to the Kerman city in south-east. Some evidence of the activity of this fault system are young morphotectonic structures and earthquake events along of this faults. To determine the content of sample’s radon, radon detector (RAD7) was used. In six out of water samples, radon levels was more than proposed emission 11.1kbm-3(MCL) by Environmental Protection Agency (EPA). The average annual effective dose in 2 regions is more than r...

Journal of Biomedical Physics and Engineering, 2020

Background: Thermoluminescence dosimetry(TLD) has been known as one of the most effective methods... more Background: Thermoluminescence dosimetry(TLD) has been known as one of the most effective methods for dose estimation in diagnostic radiology. Orthopantomogram (OPG) imaging is used by many dentists, oral and maxillofacial surgeons as an effective tool for choosing an appropriate treatment plan. Objective: This study aims to measure the entrance skin dose and the dose values received by different head and neck organs in OPG imaging using TLD dosimeters (TLD-100). Material and Methods: In this experimental study, the entrance skin dose and doses of various organs during imaging were measured by TLD dosimeters inside and on the surface of the Rando-Phantom. Doses to various organs, including thyroid, eye, esophagus, parotid and sublingual and submandibular salivary glands were measured. The measurements were repeated twice, and the dose values obtained in the two steps were compared. Results: Based on the results obtained in this study, the minimum dose values were found in Esophagus; 65.81, and 59.31 µGy, respectively. The maximum organ dose value was found for left parotid glands, 3842.42, and 3399.58 for the two measurements, respectively. Conclusion: The results show that the dose values can vary based on devices, exposure conditions, and TLD positioning.

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2015

Journal of Radioanalytical and Nuclear Chemistry, 2015

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2008

One method to measure radon gas concentration in the air with a long time of radiation is trace c... more One method to measure radon gas concentration in the air with a long time of radiation is trace chemical etching technique. There is a direct proportion between the number of traces on solid-state nuclear track detectors (SSNTDs) and activity concentration of radon. In this paper, calibration constant for a cylindrical chamber with CR-39 detector has been measured analytically. Using this