116 research outputs found
Dosimetric model of human lung and associated computer program
The dosimetric human respiratory tract model given in ICRP Publication 66
and ICRPVol. 32 is briefly described in this paper. The associated home-written
computer programs for calculations of radiation dose from radon and its short-lived
progeny are presented, together with some representative results.Author Affiliation: D Nikezic and K N Yu
1.University of Kragujevac, Faculty of Science, R. Domanovic 12, Kragujevac, Serbia
2.City University of Hong Kong, Department of Physics and Materials Science, Hong
Kong, P. R. China
E-mail : [email protected] of Kragujevac, Faculty of Science, R. Domanovic 12, Kragujevac, Serbia
2City University of Hong Kong, Department of Physics and Materials Science, Hong
Kong, P. R. Chin
A short note on the joint entropy of n/2-wise independence
In this note, we prove a tight lower bound on the joint entropy of
unbiased Bernoulli random variables which are -wise independent. For
general -wise independence, we give new lower bounds by adapting Navon and
Samorodnitsky's Fourier proof of the `LP bound' on error correcting codes. This
counts as partial progress on a problem asked by Gavinsky and Pudl\'ak.Comment: 6 pages, some errors fixe
Multiple stressor effects of radon and phthalates in children: background information and future research
The present paper reviews available background information for studying multiple stressor effects of radon (222Rn) and phthalates in children and provides insights on future directions. In realistic situations, living organisms are collectively subjected to many environmental stressors, with the resultant effects being referred to as multiple stressor effects. Radon is a naturally occurring radioactive gas that can lead to lung cancers. On the other hand, phthalates are semi-volatile organic compounds widely applied as plasticizers to provide flexibility to plastic in consumer products. Links of phthalates to various health effects have been reported, including allergy and asthma. In the present review, the focus on indoor contaminants was due to their higher concentrations and to the higher indoor occupancy factor, while the focus on the pediatric population was due to their inherent sensitivity and their spending more time close to the floor. Two main future directions in studying multiple stressor effects of radon and phthalates in children were proposed. The first one was on computational modeling and micro-dosimetric studies, and the second one was on biological studies. In particular, dose-response relationship and effect-specific models for combined exposures to radon and phthalates would be necessary. The ideas and methodology behind such proposed research work are also applicable to studies on multiple stressor effects of collective exposures to other significant airborne contaminants, and to population groups other than children
Active and passive radon concentration measurements and first-step mapping in schools of Banja Luka, Republic of Srpska
Radon concentration measurements were performed in all 25 primary schools in Banja Luka city, the capital of Republika Srpska, during 2011 and 2012, using both active RAD7 continual radon measuring instruments and CR-39 passive (commercially known as Gamma) detectors. The two complimentary methods were employed not only to obtain annual averages, but also to study the dynamics of radon concentration changes during the week. For each school, average and temporal variations of radon concentrations were analysed, taking into consideration local geology, building materials and meteorological conditions. The influence of forced ventilation, caused by frequent opening of doors and windows during working hours, with typical dawn and weekend peaks is evident in most but not all schools. Elevated levels of radon concentration (>400 Bq m-3) were found in a few schools using both methods. Although high correlation factor of 0.8 between passive and active methods was found, still short-time (one-week) measurements cannot be used for annual estimation of radon activity but screening one. Thus, the conclusion concerns only long time measurements as valid indicator of annual radon activity.JRC.E.8-Nuclear securit
Nuclear Track Detectors. Searches for Exotic Particles
We used Nuclear Track Detectors (NTD) CR39 and Makrofol for many purposes: i)
Exposures at the SPS and at lower energy accelerator heavy ion beams for
calibration purposes and for fragmentation studies. ii) Searches for GUT and
Intermediate Mass Magnetic Monopoles (IMM), nuclearites, Q-balls and
strangelets in the cosmic radiation. The MACRO experiment in the Gran Sasso
underground lab, with ~1000 m^2 of CR39 detectors (plus scintillators and
streamer tubes), established an upper limit for superheavy GUT poles at the
level of 1.4x10^-16 cm^-2 s^-1 sr^-1 for 4x10^-5 <beta<1. The SLIM experiment
at the high altitude Chacaltaya lab (5230 m a.s.l.), using 427 m^2 of CR39
detectors exposed for 4.22 y, gave an upper limit for IMMs of ~1.3x10^-15 cm^-2
s^-1 sr^-1. The experiments yielded interesting upper limits also on the fluxes
of the other mentioned exotic particles. iii) Environmental studies, radiation
monitoring, neutron dosimetry.Comment: Talk given at "New Trends In High-Energy Physics" (experiment,
phenomenology, theory) Yalta, Crimea, Ukraine, September 27-October 4, 200
A computer program TRACK_P for studying proton tracks in PADC detectors
A computer program for studying proton tracks in solid state nuclear track detectors was developed and described in this paper. The program was written in Fortran 90, with an additional tool for visualizing the track appearance as seen under the optical microscope in the transmission mode, which was written in the Python programming language. Measurable track parameters were determined and displayed in the application window and written in a data file. Three-dimensional representation of tracks was enabled. Examples of calculated tracks were also given in the present paper. Keywords: Solid state nuclear track detectors, CR-39, Proton track
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