Abstract:
:Tests were conducted to characterize the uniformity of velocity and tracer gas profiles in a square and a rectangular duct with respect to defining the suitability of locations for single point sampling of gaseous contaminants. Several configurations, such as a straight duct with unidirectional flow at the entrance section and straight ducts preceded by mixing elements (a 90 degrees mitered bend and double 90 degrees bends in S- and U-type configurations) were tested. Results are compared with those from circular ducts. For a straight duct of square cross section, which is not preceded by a mixing element, the coefficients of variation (COV) of tracer gas concentration at 19 duct diameters downstream of the gas release location is 143% (center release of tracer gas). COVs of velocity and tracer gas concentration in a straight square duct 9.5 duct diameters downstream of a 90 degrees mitered bend are 6% and 24.3% (top inside release), respectively, which does not meet the ANSI N13.1 limit of 20% for the tracer gas COV. In case of the rectangular duct with a 3:1 (width to height) aspect ratio, COVs of velocity and tracer gas concentration at 9 duct diameters downstream of a 90 degrees mitered bend are 29% and 62% (bottom inside release), respectively. A mixing element in a square duct comprised of two 90 degrees mitered bends in a U-configuration produces results similar to those obtained with a single 90 degrees bend. However, COVs of velocity and tracer gas concentration in a square duct 6 duct diameters downstream of an S-type double bend are 10.6% and 8.3% (top inside release), respectively, which comply with the ANSI tracer gas and velocity criteria for single point representative sampling. When mixing elements were employed in square ducts, the COV results were comparable with those of other researchers for circular ducts.
journal_name
Health Physjournal_title
Health physicsauthors
Seo Y,McFarland AR,Ortiz CA,O'Neal DLdoi
10.1097/01.HP.0000203325.62672.39subject
Has Abstractpub_date
2006-07-01 00:00:00pages
47-57issue
1eissn
0017-9078issn
1538-5159pii
00004032-200607000-00007journal_volume
91pub_type
杂志文章相关文献
HEALTH PHYSICS文献大全abstract::Thermoluminescent detectors (TLDs) can provide accurate and precise measurements for both patient and personnel dosimetry in the medical imaging environment. They have the advantages of tissue equivalency, an excellent dynamic range, and dose rate independence. In the work reported here, experiments with planar x-ray,...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/00004032-199012000-00006
更新日期:1990-12-01 00:00:00
abstract:INTRODUCTION:Following critiques of multiple personal contamination events from entries into the Oak Ridge National Laboratory's Spallation Neutron Source Transfer Bay, it was considered that the most likely causes for contamination were personal protective clothing doffing errors or moisture (sweat) allowing contamina...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/HP.0000000000001275
更新日期:2020-08-01 00:00:00
abstract::One goal of this research was to reproduce the photon specific absorbed fraction calculations of Cristy and Eckerman using their gastrointestinal (GI) tract model. A second goal was to calculate photon specific absorbed fraction values for their GI tract model using electron tracking techniques. A final goal was to ca...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/00004032-199609000-00005
更新日期:1996-09-01 00:00:00
abstract::A simple approximation for estimating the centerline gamma absorbed dose rates due to a continuous Gaussian plume was developed. To simplify the integration of the dose integral, this approach makes use of the Gaussian cloud concentration distribution. The solution is expressed in terms of the I1 and I2 integrals whic...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/00004032-198708000-00004
更新日期:1987-08-01 00:00:00
abstract::In vivo L-band electron paramagnetic resonance tooth dosimetry is a newly developed and very promising method for retrospective biodosimetry in individuals who may have been exposed to significant levels of ionizing radiation. The present study aimed to determine the relationships among enamel thickness, enamel area, ...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/HP.0000000000000698
更新日期:2017-10-01 00:00:00
abstract::In 193 cases autopsied between 1945 and 1980, all persons who had been intravascularly injected with Thorotrast in life, the authors found 131 malignant hepatic tumors, 20 liver cirrhoses, 6 myeloid leukemias, 4 erythroleukemias, 5 aplastic anemias, 4 lung cancers, 1 mesothelioma and 1 osteosarcoma. The causes of deat...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/00004032-198306001-00025
更新日期:1983-01-01 00:00:00
abstract::The natural radioactivity in some rock samples in Ikogosi-Ekiti, Southwestern Nigeria, has been measured using a very sensitive gamma spectroscopic system consisting of a 76 mm x 76 mm NaI(TI) scintillation detector system coupled to a versatile Canberra Series 10 plus multichannel analyzer. The average concentrations...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/00004032-200008000-00013
更新日期:2000-08-01 00:00:00
abstract::This document describes the attributes of an alpha spectroscopy counting and analysis system called Low Level Pulse Height Analysis (LLPHA). It was developed for multi-sample alpha spectroscopy analysis. The LLPHA system is controlled by a MIK-11/2 microcomputer with 28K of memory and uses a double-density, dual flopp...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/00004032-198403000-00014
更新日期:1984-03-01 00:00:00
abstract::We present a theoretical study of the complex relation between radon and its long-lived progeny implanted in glass surfaces. The well known (extended) Jacobi room model, which is normally used to describe radon and its progeny in a room, was transformed into a two-parameter model revealing a linear correlation between...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/00004032-200010000-00006
更新日期:2000-10-01 00:00:00
abstract::More than 150 data sets giving time-dependent concentrations of 131I and 137Cs in feed and milk of cows after the Chernobyl accident are evaluated using a minimal compartmental modeling approach. Transfer of cesium via the grass-cow-milk pathway is adequately described by a three-compartmental model. No unique model r...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/00004032-199406000-00005
更新日期:1994-06-01 00:00:00
abstract::Recently, data on exposures of humans as well as animals to fission products in plumes emitted by underground Soviet tests have been declassified by the Khazakhstan government and published in English. Similar human intakes of gross fission product mixtures that caused acute prodromal symptoms have not been previously...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/01.HP.0000326453.18919.e2
更新日期:2009-01-01 00:00:00
abstract::With possibilities for radiation terrorism and intensified concerns about nuclear accidents since the recent Fukushima Daiichi event, the potential exposure of large numbers of individuals to radiation that could lead to acute clinical effects has become a major concern. For the medical community to cope with such an ...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/HP.0b013e3182588d92
更新日期:2012-09-01 00:00:00
abstract::With more than 80 reported/confirmed accidental melts worldwide since 1983 and still counting, potential contamination by radioactive materials remains as a major concern among recycled scrap and steel companies. Some of these events were catastrophic and have cost the industry millions of dollars in business and, at ...
journal_title:Health physics
pub_type: 杂志文章,评审
doi:10.1097/01.HP.0000236781.15424.4a
更新日期:2006-11-01 00:00:00
abstract::Published in December 2014, National Council on Radiation Protection and Measurements Report No. 175, Decision Making for Late-Phase Recovery from Major Nuclear or Radiological Incidents, emphasizes the importance of local, state, and national plans addressing late-phase issues and decision-making processes concurrent...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/HP.0000000000000784
更新日期:2018-02-01 00:00:00
abstract::Findings of the Life Span Study (LSS) cohort of atomic-bomb survivors are a primary source for quantitative risk estimates that underlie radiation protection. Because of the size and length of follow-up, the LSS provides considerable information on both the nature of the dose response and on how radiation-associated e...
journal_title:Health physics
pub_type: 杂志文章,评审
doi:10.1097/00004032-200307000-00010
更新日期:2003-07-01 00:00:00
abstract::When patients are exposed to ionizing radiation for medical diagnosis or treatment, the procedure being performed should be justified, and the amount of ionizing radiation used should be commensurate with the medical purpose. A legal limit on the amount of ionizing radiation used for medical exposure of a patient does...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/HP.0000000000000988
更新日期:2019-02-01 00:00:00
abstract::Nineteen UF6/UO2F2 inhalation studies were undertaken in purebred, female beagle dogs (N = 16) to examine inter alia, (a) the possible relations of exposure, whole body, lung and renal uranium levels to excretion rates; (b) the threshold U6+ dose and renal concentration for renal injury; (c) the distribution and reten...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/00004032-198212000-00008
更新日期:1982-12-01 00:00:00
abstract::Determining the consumption of milk contaminated with 131I, resulting from atmospheric nuclear weapons tests conducted at the Nevada Test Site, by the United States population during the 1950s constitutes one part of the methodology used by the National Cancer Institute to assess radiation exposures to Americans. In o...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/00004032-199011000-00013
更新日期:1990-11-01 00:00:00
abstract::The U.S. Environmental Protection Agency (EPA) operates an environmentally controlled chamber for purposes of exposing various radon and decay product measurement equipment to known (222)Rn concentrations. Exposure durations range from 1 h to several months, and (222)Rn concentrations vary between 37 and 4,440 Bq m(-3...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/HP.0b013e3182712e5a
更新日期:2013-02-01 00:00:00
abstract::The former Apollo facility converted enriched uranium hexafluoride into uranium oxide for shipment to nuclear fuel fabrication plants from 1957 to 1983. This paper describes quantification of the source term from the Apollo facility in terms of quantities of uranium released, particle size, and solubility characterist...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/HP.0000000000001343
更新日期:2020-12-11 00:00:00
abstract::Program Area Committee 5 of the National Council on Radiation Protection and Measurements (NCRP) focuses its activities on environmental radiation and radioactive waste issues. The Committee completed a number of reports in these subject areas, most recently NCRP Report No. 175, Decision Making for Late-Phase Recovery...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/HP.0000000000000418
更新日期:2016-02-01 00:00:00
abstract::The yield of chromosome aberrations (dicentric and ring chromosomes) was determined for five patients who had been extensively exposed to diagnostic x rays. Remarkably high aberration yields were obtained for each of them leading to correspondingly high equivalent whole body doses ("biological dosimetry"). The contrib...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/00004032-199502000-00012
更新日期:1995-02-01 00:00:00
abstract::The movement through the environment and the toxicity to plants of 99Tc have been studied. However, information is scanty on 99Tc toxicity to mammals even though this is the decisive criterion for assessing the consequences of releases of Tc. A critical tissue could be the thyroid because of its preferential accumulat...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/00004032-198908000-00014
更新日期:1989-08-01 00:00:00
abstract::The Department of Health and Human Services (DHHS) was directed by Congress to assess the risk of thyroid cancer from 131I associated with fallout from the atmospheric testing of nuclear weapons at the Nevada Test Site. The National Cancer Institute (NCI) was requested by DHHS to address Public Law 97-414, Section 7 (...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/00004032-199011000-00002
更新日期:1990-11-01 00:00:00
abstract::The scientific basis for the physical and biological effectiveness of particle radiations has emerged from many decades of meticulous basic research. A diverse array of biologically relevant consequences at the molecular, cellular, tissue, and organism level have been reported, but what are the key processes and mecha...
journal_title:Health physics
pub_type:
doi:10.1097/HP.0b013e31826a5b85
更新日期:2012-11-01 00:00:00
abstract::Dissolution characteristics of mixed-oxide nuclear fuels are important considerations for prediction of biological behavior of inhaled particles. Four representative industrial mixed-oxide powders were obtained from fuel fabrication enclosures. Studies of the dissolution of Pu, Am and U from aerosol particles of these...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/00004032-198312000-00001
更新日期:1983-12-01 00:00:00
abstract::At least 350,000 workers at U.S. radiation facilities are being followed up to monitor their mortality experience, with particular reference to cancer. Although these studies are expensive, they are needed from the standpoint of public health and radiation protection; they also provide a useful check that the risk ext...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/00004032-199007000-00007
更新日期:1990-07-01 00:00:00
abstract::The estimated values of time-integrated dose equivalent are different if one assumes continuous intake, such as is the case for longer-term environmental exposures, instead of instantaneous intake, which is the assumption made for most standardized computational procedures. This paper presents the solutions of the fir...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/00004032-199807000-00013
更新日期:1998-07-01 00:00:00
abstract::The author was invited to talk about ICRP perceptions of a look to the future. Many questions will be addressed when the International Commission on Radiological Protection (ICRP) initiates a revision of its basic recommendations from 1977, which were published in ICRP Publication 26. This process will take several ye...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/00004032-198808000-00004
更新日期:1988-08-01 00:00:00
abstract::Assumptions supporting a chronic aqueous release methodology are inappropriate for estimating dose from accidental discharges. A method of modeling acute or accidental releases is being developed for predicting maximum individual dose. Standardization of consumption rates and usage factors for acute aqueous releases i...
journal_title:Health physics
pub_type: 杂志文章
doi:10.1097/00004032-199206000-00011
更新日期:1992-06-01 00:00:00