Thermoluminescence as a potential means of dating siliceous ocean sediments

1976 ◽  
Vol 13 (4) ◽  
pp. 593-596 ◽  
Author(s):  
D. J. Huntley ◽  
H. P. Johnson
Keyword(s):  
Radiation Dose ◽  
North Pacific ◽  
Deep Sea ◽  
Radiation Sensitivity ◽  
Single Peak ◽  
Dose Rates ◽  
Thermoluminescence Dating ◽  
Limiting Value

The natural thermoluminescence of siliceous shell separated from two North Pacific deep-sea cores has been measured. The thermoluminescence shows a single peak at ~240 °C, the intensity of which increases with depth up to a limiting value. Measurements of sample radiation-sensitivity and the determination of radiation dose rates are also presented. It is concluded that thermoluminescence dating is a potentially viable dating technique for such material.

Appendix IV: Thermoluminescence Dating of Daub from Site 1: The Timber Circle

1994 ◽  
Vol 60 (S1) ◽  
pp. 30-31
Author(s):  
N Detenham
Keyword(s):  
Radiation Dose ◽  
Bronze Age ◽  
Iron Age ◽  
Beta Activity ◽  
Metal Working ◽  
Thermoluminescence Dating ◽  
Burnt Clay ◽  
Dating Method ◽  
Radioactivity Measurements

A sample of burnt clay (SBC 1), recovered from context 80, c. 0.5 m deep in the central pit of the umber ciicle, was examined by thermoluminescence (TL). The clay was expected to be either Bronze Age or Iron Age in date, being associated either with the timber circle or with the Iron Age metal working in the top of the central pit.The TL dating method measures the time that has elapsed since the heating of the material (which zeroes the TL signal). The measurement consists of firstly a determination of the radiation dose received by the sample since its heating (through the examination of its TL) and secondly an assessment of the rate at which the radiation dose was received (carried out by radioactivity measurements). Further descriptions of the method are given by Aitken (1985) and Zimmerman (1971).The outer 2 mm or more of the sample were cut away to remove those pans that had been exposed to light and to the alpha and beta activity of the surrounding sediment The interior piece was crushed, and fine grains of 2-10 mu were separated by suspension in dilute hydrochloric acid. The grains were then washed in water, methanol and acetone before deposition onto aluminium discs.

scholarly journals Radiation Awareness for Endovascular Abdominal Aortic Aneurysm Repair in the Hybrid Operating Room: An Instant Operator Risk Chart for Daily Practice

2021 ◽  
pp. 152660282110074
Author(s):  
Quirina M. B. de Ruiter ◽  
Frans L. Moll ◽  
Constantijn E. V. B. Hazenberg ◽  
Joost A. van Herwaarden
Keyword(s):  
Radiation Dose ◽  
Dose Rate ◽  
Effect Size ◽  
Radiation Risk ◽  
Dose Limit ◽  
Access Site ◽  
Femoral Access ◽  
Dose Rates ◽  
Rate Prediction ◽  
Operator Dose

Introduction: While the operator radiation dose rates are correlated to patient radiation dose rates, discrepancies may exist in the effect size of each individual radiation dose predictors. An operator dose rate prediction model was developed, compared with the patient dose rate prediction model, and converted to an instant operator risk chart. Materials and Methods: The radiation dose rates (DRoperator for the operator and DRpatient for the patient) from 12,865 abdomen X-ray acquisitions were selected from 50 unique patients undergoing standard or complex endovascular aortic repair (EVAR) in the hybrid operating room with a fixed C-arm. The radiation dose rates were analyzed using a log-linear multivariable mixed model (with the patient as the random effect) and incorporated varying (patient and C-arm) radiation dose predictors combined with the vascular access site. The operator dose rate models were used to predict the expected radiation exposure duration until an operator may be at risk to reach the 20 mSv year dose limit. The dose rate prediction models were translated into an instant operator radiation risk chart. Results: In the multivariate patient and operator fluoroscopy dose rate models, lower DRoperator than DRpatient effect size was found for radiation protocol (2.06 for patient vs 1.4 for operator changing from low to medium protocol) and C-arm angulation. Comparable effect sizes for both DRoperator and DRpatient were found for body mass index (1.25 for patient and 1.27 for the operator) and irradiated field. A higher effect size for the DRoperator than DRpatient was found for C-arm rotation (1.24 for the patient vs 1.69 for the operator) and exchanging from femoral access site to brachial access (1.05 for patient vs 2.5 for the operator). Operators may reach their yearly 20 mSv year dose limit after 941 minutes from the femoral access vs 358 minutes of digital subtraction angiography radiation from the brachial access. Conclusion: The operator dose rates were correlated to patient dose rate; however, C-arm angulation and changing from femoral to brachial vascular access site may disproportionally increase the operator radiation risk compared with the patient radiation risk. An instant risk chart may improve operator dose awareness during EVAR.

1948 ORGAN SPECIFIC RADIATION DOSE RATES AND EFFECTIVE DOSE DURING PERCUTANEOUS NEPHROLITHOTOMY

2012 ◽  
Vol 187 (4S) ◽  
Author(s):  
Michael Lipkin ◽  
John Mancini ◽  
Agnes Wang ◽  
Greta Toncheva ◽  
Colin Anderson-Evans ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Effective Dose ◽  
Percutaneous Nephrolithotomy ◽  
Dose Rates ◽  
Organ Specific

The Reproductive Biology of Ophiacantha Bidentata (Echinodermata: Ophiuroidea) From The Rockall Trough

1982 ◽  
Vol 62 (1) ◽  
pp. 45-55 ◽  
Author(s):  
P. A. Tyler ◽  
J. D. Gage
Keyword(s):  
Reproductive Biology ◽  
Deep Water ◽  
Larval Stage ◽  
North Pacific ◽  
Deep Sea ◽  
Direct Development ◽  
The Arctic ◽  
Shallow Waters ◽  
Arctic Seas ◽  
Rockall Trough

INTRODUCTIONOphiacantha bidentata (Retzius) is a widespread arctic-boreal ophiuroid with a circumpolar distribution in the shallow waters of the Arctic seas and penetrating into the deep sea of the.North Atlantic and North Pacific (Mortensen, 1927, 1933a; D'yakonov, 1954). Early observations of this species were confined to defining zoogeo-graphical and taxonomic criteria including the separation of deep water specimens as the variety fraterna (Farran, 1912; Grieg, 1921; Mortensen, 1933a). Mortensen (1910) and Thorson (1936, pp. 18–26) noted the large eggs (o.8 mm diameter) in specimens from Greenland and Thorson (1936) proposed that this species had ‘big eggs rich in yolk, shed directly into the sea. Much reduced larval stage or direct development’. This evidence is supported by observations of O. bidentata from the White and Barents Seas (Semenova, Mileikovsky & Nesis, 1964; Kaufman, 1974)..

scholarly journals The shrinkage of soils

1917 ◽  
Vol 8 (3) ◽  
pp. 312-330 ◽  
Author(s):  
H. A. Tempany
Keyword(s):  
Linear Relationship ◽  
Pore Space ◽  
Linear Shrinkage ◽  
Fine Silt ◽  
Leeward Islands ◽  
Physical Composition ◽  
Colloidal Clay ◽  
Internal Pore ◽  
Limiting Value

1. By determination of the internal pore space in blocks of soils and comparison with the observed value for the linear shrinkage it is found that a linear relationship appears to exist between the two values.2. By extrapolating the curve thus obtained an approximation for the limiting value of the shrinkage in the case of pure colloidal clay is arrived at amounting to approximately 23 per cent.3. On this assumption it becomes possible to calculate the approximate content of colloidal material in any soil from a knowledge of the linear shrinkage.4. Results are adduced, showing the values obtained for the shrinkage in the case of separated fine silt and clay fractions in the case of two soils of known shrinkage and physical composition, and compared with the values calculated from previous assumptions.5. The results of the calculation of the content of colloidal clay in the foregoing manner in the case of 16 Leeward Islands soils are appended.

Study on Radiation Dose Calculation of PWR Spent Fuel Storage and Transportation

2021 ◽  
Author(s):  
Wen Yang ◽  
Xing Li ◽  
Jinrong Qiu ◽  
Lun Zhou
Keyword(s):  
Radiation Dose ◽  
Normal Condition ◽  
Radiation Safety ◽  
Spent Fuel ◽  
Dose Rates ◽  
Storage Pool ◽  
Transport Container ◽  
Photon Dose ◽  
Spent Fuel Storage ◽  
Fuel Storage

Abstract With the rapid development of nuclear energy, spent fuel will accumulate in large quantities. Spent fuel is generally cooled and placed in a storage pool, and then transported to a reprocessing plant at an appropriate time. Because spent fuel is content with a high level of radiation, spent fuel storage and transportation safety play important roles in the nuclear safety. Radiation dose safety are checked and validated using source analysis and Monte Carlo method to establish a radiation dose rate calculation model for PWR spent fuel storage pool and transport container. The calculation results show that the neutron and photon dose rates decrease exponentially with increase of water level under normal condition of storage pool. The attenuation multiples of neutron and photon dose rates are 4.64 and 1.59, respectively. According to radiation dose levels in different water height situations, spent fuel pool under loss of coolant accident can be divides into five workplaces. They are supervision zone, regular zone, intermittent zone, restricted zone and radiation zone. Under normal condition of transport container, the dose rates at the surface of the container and at a distance of 1 m from the surface are 0.1759 mSv/h and 0.0732 mSv/h, respectively. The dose rates decrease with the increasing radius of break accident, and dose rate at the surface of the transport container is 0.278 mSv/h when the break radius is 20 cm. Transport container conforms to the radiation safety standards of International Atomic Energy Agency (IAEA). This study can provide some reference for radiation safety analysis of spent fuel storage and transportation.

scholarly journals Adenosine Triphosphate Measurement in Deep Sea Using a Microfluidic Device

Micromachines ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 370 ◽  
Author(s):  
Tatsuhiro Fukuba ◽  
Takuroh Noguchi ◽  
Kei Okamura ◽  
Teruo Fujii
Keyword(s):  
Adenosine Triphosphate ◽  
Microfluidic Device ◽  
Deep Sea ◽  
Temperature Sensor ◽  
Biochemical Parameter ◽  
Underwater Vehicle ◽  
Luciferase Assay ◽  
Bioluminescence Intensity

Total ATP (adenosine triphosphate) concentration is a useful biochemical parameter for detecting microbial biomass or biogeochemical activity anomalies in the natural environment. In this study, we describe the development and evaluation of a new version of in situ ATP analyzer improved for the continuous and quantitative determination of ATP in submarine environments. We integrated a transparent microfluidic device containing a microchannel for cell lysis and a channel for the bioluminescence L–L (luciferin–luciferase) assay with a miniature pumping unit and a photometry module for the measurement of the bioluminescence intensity. A heater and a temperature sensor were also included in the system to maintain an optimal temperature for the L–L reaction. In this study, the analyzer was evaluated in deep sea environments, reaching a depth of 200 m using a remotely operated underwater vehicle. We show that the ATP analyzer successfully operated in the deep-sea environment and accurately quantified total ATP within the concentration lower than 5 × 10−11 M.

Sign in / Sign up

Export Citation Format

Share Document