Rate Conversion Factors Research Articles

A Study on the Deduction of Major Construction Wastes in Construction Phase through Environmental Impact Assessment

The purpose of this study was to deduce the major construction wastes to be managed using environmental impact assessment for construction wastes generated in the construction phase. To accomplish this, the amount of construction waste discharged in the construction phase was analyzed using loss rate and weight conversion factor in the Standard of Estimate for Construction Works. Based on the result of construction waste generation deduced, major construction wastes were extracted with consideration on 6 comprehensive environmental impacts including potential, abiotic depletion potential, acidification potential, eutrophication potential, ozone depletion potential, and photochemical ozone creation potential. As a result, 5 major building materials such as concrete, concrete block, rebar, cement and polystyrene panel were deduced as major cpmstruction wastes in construction phase.

Comparison of measured rain attenuation in the 10.982‐GHz band with predictions and sensitivity analysis

SummaryThe campaign to collect rain attenuation data on terrestrial links had commenced in Malaysian tropical climates for almost two decades. The terrestrial data so far collected have been greatly utilized to derive useful statistics for various microwave applications, such as frequency scaling, rain rate conversion factor, 1‐min rain rate contour maps, wet antenna losses, and fade slope duration analysis. However, there is still severe scarcity of rain attenuation data on earth–space links in Malaysia. The results of the 2‐year measurement (January 2009–December 2010) of rain rates and rain‐induced attenuation in vertically polarized signals propagating at 10.982 GHz have been presented in this paper. The rain attenuation over the link path was measured at Islamic International University Malaysia and compared with ITU‐R P.618‐10 and Crane global models in this paper. The test results show that the two prediction models seem inadequate for predicting rain attenuation in the Ku‐band in Malaysia. Sensitivity analysis performed on measured data also reveals that the sensitivity variables depend on rain rate. Copyright © 2014 John Wiley & Sons, Ltd.

Characterization of 222Rn and meteorological parameters in Uro houses at South Kordofan state

This study was carried out to assess and map indoor radon concentration and to estimate radiation dose in Uro town in Sudan's South Kordofan state. A portable radon meter (RRA-01M-03), equipped with simple sensors of meteorological parameters has been used for carrying out radon measurement. The annual absorbed dose from the corresponding measured radon concentration was calculated using dose rate conversion factors of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The corresponding annual effective dose and equivalent dose to the lungs were estimated. Measured activity concentrations of 222Rn, annual absorbed dose, annual effective dose and equivalent dose to the lungs were found in the range 20–4482 Bq/m3, 0.32–70.67 mSv/y, 0.76–169.61 mSv−y and 0.16 × 10−7 to 35,856 × 3.5856 × 10−11 mSv−y, with geometric mean 109.43 Bq/m3, 1.73, 4.16 and 1.1 × 10−7 mSv−y, respectively. Upon comparing the results with global data, it was found with the exception of six samples, the obtained values fall far below the action level of 200–600 Bq/m3 recommended by the International Commission on Radiological Protection. However, the geometric mean is higher than the reported average global indoor radon concentration. Meteorological parameters were measured and no correlation was noted between radon concentration and these parameters. The overall annual effective dose was higher than the UNSCEAR recommended reference dose level of 1.0 mSv−y.

Skin dose rate conversion factors after contamination with radiopharmaceuticals: influence of contamination area, epidermal thickness and percutaneous absorption

Skin contamination with radiopharmaceuticals can occur during biomedical research and daily nuclear medicine practice as a result of accidental spills, after contact with bodily fluids of patients or by inattentively touching contaminated materials. Skin dose assessment should be carried out by repeated quantification to map the course of the contamination together with the use of appropriate skin dose rate conversion factors. Contamination is generally characterised by local spots on the palmar surface of the hand and complete decontamination is difficult as a result of percutaneous absorption. This specific issue requires special consideration as to the skin dose rate conversion factors as a measure for the absorbed dose rate to the basal layer of the epidermis. In this work we used Monte Carlo simulations to study the influence of the contamination area, the epidermal thickness and the percutaneous absorption on the absorbed skin dose rate conversion factors for a set of 39 medical radionuclides. The results show that the absorbed dose to the basal layer of the epidermis can differ by up to two orders of magnitude from the operational quantity Hp(0.07) when using an appropriate epidermal thickness in combination with the effect of percutaneous absorption.

Display Applications of Electrowetting

A reflective display device based on electrowetting technology exhibits high reflection index over 40% and contrast ratio over 15 (conventional paper has reflection index of 60% and contrast index of 15). In addition to the attractive optical properties, this technology manifests a fast video response rate (<10 ms) and colour conversion factor of 67% which is four times higher than standard electrophoretic displays. These factors show that electrowetting technology is a strong alternative to electrophoretic technique which enables reflective displays available to the e-reader market. This technology offers advantages of insensitivity to cell- gap variations and thus can be used to create electronic paper with excellent video capability at low cost. In this review we present the working principle, fabrication procedure and electro-optic response study of electrowetting display. Different challenges still to be overcome also have been discussed in detail.

U-Pb zircon in situ dating with LA-MC-ICP-MS using a mixed detector configuration

The LA-MC-ICP-MS method applied to U-Pb in situ dating is still rapidly evolving due to improvements in both lasers and ICP-MS. To test the validity and reproducibility of the method, 5 different zircon samples, including the standard Temora-2, ranging in age between 2.2 Ga and 246 Ma, were dated using both LA-MC-ICP-MS and SHRIMP. The selected zircons were dated by SHRIMP and, after gentle polishing, the laser spot was driven to the same site or on the same zircon phase with a 213 nm laser microprobe coupled to a multi-collector mixed system. The data were collected with a routine spot size of 25 μm and, in some cases, of 15 and 40 μm. A careful cross-calibration using a diluted U-Th-Pb solution to calculate the Faraday reading to counting rate conversion factors and the highly suitable GJ-1 standard zircon for external calibrations were of paramount importance for obtaining reliable results. All age results were concordant within the experimental errors. The assigned age errors using the LA-MC-ICP-MS technique were, in most cases, higher than those obtained by SHRIMP, but if we are not faced with a high resolution stratigraphy, the laser technique has certain advantages.

Calculation of dose rate conversion factors for 238U, 232Th and 40K in concrete structures of various dimensions, with application to Nis, Serbia

The absorbed gamma dose rate in indoor air due to natural radionuclides in concrete as a building material was determined in this work. The dose rate conversion factors for (238)U, (232)Th and (40)K, for standard rooms as well as rooms with different sets of dimensions, were evaluated by the point kernel technique, using Harima (geometric progression) build-up factors. The values of the conversion factors, in units (nGy h(-1) (Bq kg(-1))(-1)) calculated for the standard room are: 0.76, 0.91 and 0.070, respectively for (238)U, (232)Th and (40)K. The fitting formula was obtained for dose rate conversion factors, enabling them to be conveniently calculated for a room with arbitrary dimensions. For concrete block samples collected in the area of Niš, Serbia, the measurement of the radionuclide activity concentrations was also carried out. The evaluated absorbed dose rate conversion factors were then applied in the assessment of corresponding indoor gamma dose rates, finding that all the concrete samples fulfilled the usage requirement.

On the use of the infinite matrix assumption and associated concepts: A critical review

The infinite matrix assumption is commonly used to derive dose rates in the field of paleodosimetric dating methods. The update of nuclear data allowed calculating new dose rate conversion factors and attenuation factors for taking account of grain size. The relevance of the infinite matrix assumption was found to be limited to specific cases and a discussion of potential errors in estimating dose rates to natural dosimeters in sedimentary media is proposed. A new set of geometric features is shown to be of paramount importance for estimating dose rates in sedimentary media. To quantify these effects, Monte Carlo modelling was applied and the architecture of the programmes is described. It is also shown that proper characterization of sediment samples, coupled to the modelling of radioactivity in these sediments may provide more accurate dose rates to quartz grains, down to the single grain scale.

Gis predictive mapping of terrestrial gamma radiation in the Northern state, Sudan

This study presents the evaluation of absorbed dose in air due to gamma-emitting nuclides from (238)U and (232)Th series, (40)K and (137)Cs and the corresponding geographical information system (GIS) predictive mapping for the Northern State. Activity concentration of (238)U, (232)Th , (40)K and (137)Cs in soil samples collected from different locations have been measured using high-resolution gamma spectrometry. On average, activity concentrations were 19±4 ((238)U), 47±11 ((232)Th), 317±65 ((40)K) and 2.26 Bq kg(-1) for (137)Cs. Absorbed dose rate in air at a height of 1 m above ground surface was calculated using seven sets of dose rate conversion factors (DRCFs) and the corresponding annual effective dose was estimated. On average, the values obtained fall within a narrow range of 44 and 53 nGy h(-1), indicating that the variation in absorbed dose rate is insignificant for different DRCFs. The corresponding annual effective dose ranged from 53 to 65 µSv y(-1). Using GIS, prediction maps for concentrations of (238)U, (232)Th, (40)K and (137)Cs were produced. Also, a map for absorbed dose rate in air at a height of 1 m above the ground level was produced, which showed a trend of increasing from the west towards south-east of the State.

Methane conversion rate of bulls fattened on grass or maize silage as compared with the IPCC default values, and the long-term methane mitigation efficiency of adding acacia tannin, garlic, maca and lupine

Abating enteric methane in ruminants by feeding is considered promising, but long-term assessments are lacking. Thirty-six growing bulls were allocated to six treatments and received either grass or maize silage and concentrate. The maize silage diet was also supplemented with acacia tannin extract, garlic bulbs, maca hypocotyls, or lupine seeds. At ages of 5, 9 and 11 months, enteric methane was measured in open circuit respiratory chambers along with feed intake and excretion. Ruminal fluid was collected at slaughter. Slurry-derived methane was determined while stored at 14 °C and 27 °C for 15 weeks. Exchanging maize for grass silage increased enteric methane only on one occasion. Total system methane emission was similar between grass- and maize-silage fed bulls. Tannin decreased methane by up to 36% and, most importantly, this suppression persisted throughout the entire experiment. Tannins did not alter slurry-derived methane. Enteric methane conversion rate and methane conversion factors in slurry were always below the IPCC default values. Grass silage increased fibre digestibility and numbers of total and cellulolytic Bacteria. The study demonstrated a long-term efficacy of acacia tannin in mitigating methane. Further, the results suggest that IPCC appears to overestimate methane from growing cattle fattened on typical European diets.

Erratum to: Thin Film Growth of Germanium Selenides from PECVD of GeCl4 and Dimethyl Selenide

In the online published article, it was neglected to note that the flow rates listed in the Table 1 for the DMSe flow were based on a nitrogen flow controller. The nitrogen to DMSe flow rate conversion factor was not available for the MKS flow controller that was used. A conversion factor of 0.34 from a different flow controller manufacturer was recently found. The actual DMSe flow rate may be approximated by multiplying the table entry by 0.34. Thus for a flow rate of 5 sccm listed in the table for DMSe, the true flow rate is likely close to (0.34) 9 5 sccm = 1.7 sccm.

Influência das condições de parboilização na composição química do arroz

O objetivo deste trabalho foi avaliar a influência de diferentes tempos de maceração e autoclavagem, durante o processo de parboilização, na composição química do arroz parboilizado. Uma amostra de arroz verde, com casca e seca, foi submetida ao processo de parboilização segundo um planejamento fatorial 2² com ponto central, tendo como variáveis o tempo de maceração (4, 5 e 6 horas) e o tempo de autoclavagem (15, 22.5 e 30 minutos). Após a secagem, a amostra foi beneficiada em miniengenho, separando-se a casca juntamente com o farelo e o endosperma amiláceo. Todas as porções foram trituradas e peneiradas, recolhendo-se as porções que passaram através de 0,5 mm para serem caracterizadas quanto aos teores de umidade, cinzas, proteínas, fibras, amilose e fenóis totais. Os resultados mostraram que as condições operacionais de tempo de maceração e autoclavagem afetaram os teores de minerais, proteínas, fibras, amilose e fenóis entre o endosperma amiláceo e as porções externas do grão de maneira diferente para cada componente, sendo que o parâmetro tempo de maceração, no seu maior nível (6 horas), teve influência significativa nas frações determinadas.

SU-GG-T-360: Monte Carlo-Based Pre-Installation Proton Therapy Shielding Verification for a Single-Room Proton Therapy Facility

Purpose: To validate analytic shielding and maze calculations prior to construction of a doorless in-room accelerator proton therapy facility. Method and Materials: The MCNPX Monte Carlo program (version 2.6c) was used to model the treatment facility. LA 150 cross-sections were used for all materials available. Maze walls, floors, and shielding walls, including all passage ways were included in the room geometry. Treatment losses were modeled with an Fe target placed at isocenter. The cyclotron was geometrically modeled with anticipated proton loss points. The cyclotron was modeled both with and without localized compound shielding. Simulations were performed for gantry angles of 0°, 90°, and 180° for the target source and 0°, 90°, and 135° for the cyclotron source. The 135° beam was simulated since it places the accelerator in a direct line-of-sight of an personnel access area in the lower level shielding wall. Neutron dose equivalent and photon dose values were tallied using mesh tallies throughout the treatment room, maze, and outside of the shielding enclosure and compared with design values. Neutron dose equivalent estimates used the ICRP-74 neutron flux-to-dose rate conversion factors. Results: MCNPX simulations confirmed the analytical shielding estimates and indicated areas of under and over-shielding in the facility plans. Beyond the shielding walls, photon dose equivalent values were less than 10% of the neutron values. Neutrons streaming from the accelerator through a lower maze shielding void contribute to the personnel dose to in the treatment control area. Use of 1″ of simple compound shielding reduces this contribution by a factor of 2.25. Conclusion: MCNPX is a valuable tool for pre-installation verification of shielding design and indicate that doorless proton therapy vaults are feasible.

Assessment of absorbed dose rate in air over plowed arable lands in Sinnar State, central Sudan

The absorbed gamma-dose rate in air at a height of 1 m above ground level was calculated from activity concentrations of gamma-emitting radionuclides in arable soil samples collected from eight locations within Sinnar State using the published Dose Rate Conversion Factors. Measurements were carried out using high-resolution gamma-spectrometry. On average, the activity concentrations obtained were 38 +/- 8 ((232)Th), 17 +/- 2 ((226)Ra), 174 +/- 19 ((40)K) and 0.9 +/- 0.2 Bq kg(-1) for the fallout radionuclide (137)Cs. The average value obtained here for (232)Th is slightly higher than the corresponding world-average. The calculated absorbed dose rate in air at a height of 1 m for all sampled locations ranges from 31 to 47 nGy h(-1) with an average value of 39 +/- 7 nGy h(-1) which is characteristic of normal background radiation areas. The corresponding annual effective dose was 47.8 +/- 6 microSv y(-1). The major contribution to the total absorbed dose rate comes from (232)Th, which amounts to 61%. Recalculation of the absorbed dose rate-based gamma-energies of individual nuclides from uranium and thorium decay series and (40)K showed that the greater part of the absorbed dose from the uranium series is due to (214)Bi, whereas for the (232)Th series it is equally attributed to (228)Ac and (208)Tl.

The Influence of the Concentration of Atmospheric Radon Decay Products on the Environmental Radiation Dose Rate

It has been occasionally found from an area monitoring data obtained at an atomic power station that the daily periodical change of the environmental radiation dose rate appeared near the ground surface. It is suggested that the variation has resulted from the change of atmospheric radon concentration and that it has also depended on the geographical features of the observation point. The change component has been estimated to be up to nearly 30 percent of the environmental radiation dose rate from monitoring data. To investigate precisely the phenomena, observation was performed near a monitoring station and at other area in Fukui Prefecture during the summer. The dose rate from terrestrial radiation was 42nGy/h at the Natasho in Ooi Town and was 30nGy/h at the Kaminaka in Wakasa Town. The concentration of radon decay products in the air was 0.5-30Bq/m3 at the Natasho site and was 1-10Bq/m3 at the Kaminaka site. From the concentration of radon decay products in the atmosphere, the dose rate was respectively estimated to be 0-7.0nGy/h at the Natasho site, and to be 0-5.5nGy/h at the Kaminaka site. Furthermore, 0.26 (nGy/h)/(Bq/m3) and 0.56(nGy/h)/(Bq/m3) were estimated as the dose rate conversion factor of radon concentration in the air at the Natasho site and at the Kaminaka site, respectively.

Total beta and gamma dose rates in trapped charge dating based on beta counting

The uncertainties involved in using total beta counting to derive the dose rate term in trapped charge dating are examined. A new sample preparation technique is described; this gives a stable counting geometry and retains radon. It is confirmed that the count rate to dose rate conversion factor is relatively independent of the relative contributions of the U and Th decay series and 40K, but that there is a significant dependence for the gamma dose rate. High resolution gamma spectrometry radionuclide analyses of > 3700 representative samples are presented; these allow discussion of the typical relative contributions of the three potential sources of dose rate, e.g. it is shown that, on average, the gamma dose rate makes up 33.15 ± 0.08% of the total (beta and gamma) dose rates. By direct counting of 400 of these samples, it is then shown that beta count rates can be accurately predicted from these radionuclide analyses. However there is an overdispersion in the relative standard deviation in this relationship of ∼ 10 % . It is argued that correcting for stopping power differences from sample to sample does not reduce this overdispersion significantly. Finally, the total dose rate (beta, gamma and cosmic ray) is derived from the beta count rate in two ways: (i) using a non-linear parameterisation of the observed relationship between total beta count rate and beta and gamma dose rates, and (ii) by simply multiplying the calculated beta dose rate by a constant. It is shown that both approaches give almost equally good predictions of the total dose rates (compared to those derived from gamma spectrometry), with relative standard deviations of 5% and 6%, respectively. It is concluded that for the great majority of samples, the overall dose rate prediction obtained using beta counting alone can have an associated typical uncertainty of ∼ 5%, to which must be added the uncertainty in beta counting.

Measurement of terrestrial radiation for assessment of gamma dose from cultivated and barren saline soils of Faisalabad in Pakistan

Natural radioactivity originates from extraterrestrial sources as well as from primordial radioactive elements in the earth crust. The amount of radioactivity in soil varies widely and is a source of continuous exposure of human beings to terrestrial radioactivity that depends upon the type of soil and its uses. For the investigation of radioactivity in barren and cultivated soil, an area of about 80 ha of saline soil was selected in Pakka Anna near the city of Faisalabad in the Punjab province of Pakistan. Activity concentration levels due to 40K, 137Cs, 226Ra and 232Th were measured with HPGe detector in 250 saline soil samples collected at a spacing of about 8 ha at a depth of 0–25 cm with intervals of 5 cm depth. Activity concentration ranges of the concerned radionuclides for both of the soils were as follows: 40K, for barren and cultivated saline soil was 499–604 and 563– 629 Bq kg - 1 , respectively; 137Cs, 3.57–3.63 and 1.98– 5.15 Bq kg - 1 ; 226Ra, 24–29 and 27– 33 Bq kg - 1 , and 232Th, 49–54 and 46– 62 Bq kg - 1 . Gamma dose was estimated using the activity to dose rate conversion factors. The measured activity concentrations and the estimated radiation dose were found to be lying within the range specified in the 2000 report of UNSCEAR. Chemical analysis for Na, Ca and Mg was also carried out along with the measurement of electrical conductivity and pH of soil samples.

A new finite cloud method for calculating external exposure dose in a nuclear emergency

A new finite cloud method (5/μ method) for calculating external exposure dose in a nuclear emergency is presented in this paper. The method calculates external exposure dose over a specially constructed three-dimensional columned space, whose underside center is the location of the receptor and underside radius and height are both five times mean free path of a gamma-photon. Then, the space is divided into many grid cells for integral to calculate external exposure dose (or dose rate). The calculation values of air external exposure dose rate conversion factors and air-absorbed dose rate conversion factors by the 5/μ method are accordant with the values presented in related references. Comparing with the discrete point approximation method (DPA) [USNRC, The MESORAD Dose Assessment Model. NUREG/CR-4000 Vol. 1, 1986] and the Nomogram method [USNRC, Nomogram for Evaluation of Doses from Finite Noble Gas Clouds, NUREG-0851, 1983], which are two traditional finite cloud methods for calculating external exposure dose, the 5/μ method has a distinct advantage of more fast calculation speed, which is very important in a nuclear emergency. What is more, the 5/μ method can be applied together with three-dimensional atmospheric dispersion models.

Comparative study on the evaluation of gamma-dose rate above uranium mineralisation areas in Western Sudan

Summary Absorbed dose rate received from natural external irradiation in uranium mineralisation areas at Jebel Uro, Jebel Kurun and Jebel Mun was evaluated from the measured activity concentrations of 238U, 232Th and 40K in rock samples. The analyses were performed using alpha-spectrometry and high-resolution gamma-ray spectrometry. A great spatial variability was observed in activity concentration of the primordial radionuclides indicating complexity in geological features. Converse to Jebel Mun, Uro and Kurun deposits exhibit very high U: Th mass ratio, the feature that characterized vein deposits. The resulting absorbed dose rate at 1m above bedrock level as estimated using dose rate conversion factors (DRCF) fall within the range of 70-500nGy/h (Mun), 600-6000nGy/h (Uro) and 80-300nGy/h (Kurun). At maximum, it corresponds to annual effective dose rate of 0.6mSv, 8mSv and 0.4mSv, respectively. Uranium is the principal producer of the surface radioactivity at Uro and Kurun as it contributes 99.6 and 95 of the total absorbed dose whereas, in Jebel Mun the cause of radioactive anomaly is due to 40K and 232Th. Regression analysis showed no correlation between uranium concentration and other radionuclides. Although, radioactive equilibrium is not likely to occur in surface and near-surface geological environments, however, daughter/parent activity concentration ratios along uranium series, viz. 234U:238U, Ra:U, 230Th:U, 210Po:U do not differ from unity in both Uro and Kurun deposits.

Prospective study of HDR ( 192Ir) versus MDR ( 137Cs) intracavitary brachytherapy for carcinoma of the uterine cervix

Purpose: The aim of this study was to compare the results of high-dose rate (HDR) and medium-dose rate (MDR) intracavitary brachytherapy for carcinoma of the uterine cervix on the basis of a prospective study and to determine the dose rate conversion factor (DRCF) from low-dose rate (LDR) to MDR via HDR, because a DRCF of 0.54 from LDR to HDR has been widely accepted. Materials and Methods: Between August 1991 and July 1999, 104 patients were entered into this trial to compare results between HDR ( n = 54) and MDR ( n = 50). Three patients were excluded from this study, leaving 54 HDR patients and 47 MDR patients eligible. Method and dose of external beam radiotherapy were the same for both groups. For HDR intracavitary brachytherapy, point A dose was adjusted to 32 Gy/4 fractions for stages I and II, to 30 Gy/4 fractions for stage III, and to 22.5 Gy/3 fractions for stage IV. The corresponding values for MDR were 35.6 Gy/4 fractions, 34 Gy/4 fractions, and 25.5 Gy/3 fractions. The average dose rate at point A was 30 Gy/hour (9.0–65.2) for HDR and 1.7 Gy/hour (1.3–2.2) for MDR. We assumed a DRCF of 0.9 from MDR to HDR. Results: The 3-year cause-specific survival rates for HDR were 85%, 83%, 75%, and 0% for stages I, II, III, and IV, respectively. The corresponding figures for MDR were 100%, 82%, 58%, and 40%. Six of the HDR patients (11%) and 2 of the MDR patients (4%) developed Kottmeier's grade 2 or 3 late complications. A DRCF of 0.6 from LDR to MDR could be derived from a DRCF of 0.9 from MDR to HDR and one of 0.54 from LDR to HDR. Conclusions: There were no statistically significant differences in cause-specific survival and incidence of late complications between HDR and MDR. A DRCF of 0.6 from LDR to MDR could be determined. However, because the results of this trial were preliminary, a further study is needed.