Radiometric Method Research Articles

Empirical Relation Between Magnetic and Radiometric Survey in Bitumen Area, Ogun State, Nigeria

Abstract One of the vital roles played by both magnetic and radiometric surveys is identification and delineation of mineral deposits. The study area, Imeri, which lies between latitude 6 °45′N to 6 °48′N and longitude 3 °58′E to 3 °59′E, has been established for bitumen deposition. The responses of mineral deposition to different geophysical methods differ from place to place due to variation in climate and bedrock composition. In this study, two geophysical techniques—magnetic and radiometric methods—were adopted to investigate the magnetic anomalous and radiometric flux responses around the bitumen deposit area. The study also intends to establish a model-like relation between the radiometric parameters and the magnetic anomaly observed. Statistical inferences for the established relations were deduced using the t-test at 0.05 significance levels. The result obtained showed that uranium and thorium concentration responses along the two traverses were in good agreement with that of magnetic intensity. The claim was accounted for based on the correlation result, which ranged between 74%–79% and 84%–89% for uranium and thorium, respectively, with magnetic intensity along the two traverses. In order to validate the claim, the t-test was used. The result obtained showed that there exists no significant difference between the two geophysical methods; the result for the t-test has critical value > calculated value (p-values > 0.05). Based on this, the empirical relations were deduced for magnetic anomalous response and radiometric parameters. This work has therefore proven the two techniques to be versatile for bitumen prospecting in the study area.

A giant volcanic island in an early Martian Ocean?

Tracking early oceans on Mars has fundamental climatic and exobiological implications but requires unambiguous datable markers. Here we show that the Olympus Mons giant volcano shares morphological similarities with active volcanic islands on Earth where major constructional slope breaks systematically occur at the sea-air transition in response to sharp lava viscosity contrasts. We propose that the upper rim of the 6-km high concentric main escarpment surrounding Olympus Mons most likely formed by lava flowing into liquid water when the edifice was an active volcanic island during the late Noachian - early Hesperian. Similar features on the northern flank of the 1800 km-distant Alba Mons volcano further support an extended early Ocean initially occupying Martian lowlands. Abnormal current shoreline heights imply major surface uplift promoted by internal dynamics during the main phase of development of the Tharsis Bulge at some time during the Hesperian. After ocean retreat, the uplifted shorelines were partly blanketed by late sub-aerial activity during the Amazonian. The newly proposed volcanic shorelines can be dated by radiometric methods, constituting exceptional targets to track early liquid water at key temporal steps and provide valuable insights into the timing and fate of Martian Oceans.

WALIS dashboard: An online tool to explore a global paleo sea-level database

This paper describes the WALIS dashboard, an open-access interface to the World Atlas of Last Interglacial Shorelines (WALIS), which was developed and compiled thanks to funding from the European Research Council. WALIS is a database that includes thousands of samples (dated with different radiometric methods) and sea-level indicators formed during the Last Interglacial (125 ka). The WALIS dashboard was coded in R (shiny app) and is connected with a simplified version of the WALIS database. The app allows querying data by geographic extent or by filtering metadata. It then allows the user to download the queried data and perform simple reproducible data analysis. The WALIS dashboard can be used both online and offline.

Calibration Method for Airborne Infrared Optical Systems in a Non-Thermal Equilibrium State.

Airborne infrared optical systems equipped with multiple cooled infrared cameras are commonly utilized for quantitative radiometry and thermometry measurements. Radiometric calibration is crucial for ensuring the accuracy and quantitative application of remote sensing camera data. Conventional radiometric calibration methods that consider internal stray radiation are usually based on the assumption that the entire system is in thermal equilibrium. However, this assumption leads to significant errors when applying the radiometric calibration results in actual mission scenarios. To address this issue, we analyzed the changes in optical temperature within the system and developed a simplified model to account for the internal stray radiation in the non-thermal equilibrium state. Building upon this model, we proposed an enhanced radiometric calibration method, which was applied to the absolute radiometric calibration procedure of the system. The radiometric calibration experiment, conducted on the medium-wave channel of the system within a temperature test chamber, demonstrated that the proposed method can achieve a calibration accuracy exceeding 3.78% within an ambient temperature range of -30 °C to 15 °C. Additionally, the maximum temperature measurement error was found to be less than ±1.01 °C.

Metabolism and Chemical Degradation of New Antidiabetic Drugs (Part II): A Review of Analytical Approaches for Analysis of Gliptins.

This paper is part II of the review on metabolism and chemical degradation of new antidiabetic drugs from glutides, gliflozins and gliptins. It is well known that metabolism data can be helpful for deriving safe levels of degradation impurities and their qualifying as far as toxicological aspects are concerned. As a result, it could link the quality of respective pharmaceutical products to clinical practice and patients. Some overlapping pathways of transformations of these important drugs of different chemical structures and different mechanisms of action were discussed. At the same time, the paper summarized interesting analytical tools for conducting modern drug metabolism as well as drug degradation experiments. The methods described here include liquid chromatography (LC) and liquid chromatography coupled with mass spectrometry (LC-MS or LC-MS/MS), which are widely used for detection and quantitative measurements of the drugs, their metabolites and degradants, as well as radiometric methods that are suitable for pharmacokinetic experiments. Special attention was paid to dedicated types of packing in chromatographic columns, as well as to special solutions in the LC-MS procedures. The present part addresses the analytical approaches elaborated for examining the metabolism and degradation pathways of gliptins that are dipeptidyl peptidase 4 (DPP-4) inhibitors.

Mathematical Substantiation of the Monitoring of Corrosion Processes in Process Equipment by Radiometric Method

Mathematical Substantiation of the Monitoring of Corrosion Processes in Process Equipment by Radiometric Method

Substantiation of the Methodology for Determining Ash Content by X-ray Radiometric Method

The purpose of the research is an experimental substantiation of the methodology for determining ash content by the X-ray radiometric method. A brief overview of modern methods of coal ash content control is given. One of the independent directions of solid fuel quality control is the X-ray radiometric method. To increase the accuracy of determining the ash content of coal, a technique using two sources is proposed. The proposed method, using secondary radiation backscattered by coal and fluorescent radiation of elements, gives better results than the well-known method for determining ash content by backscattered radiatio

Fast and easy radiometric calibration method integration time insensitive for infrared thermography

The radiometric calibration of an infrared camera is a crucial and unavoidable step to obtain an accurate temperature measurement. The calibration does the link between the sensor digital levels and the actual radiometric temperature. Although this step is critical and necessary to obtain meaningful measurement, it is a complex and time-consuming procedure, which requires many experimental data acquisitions and an algorithm to process them. This article proposes a method based on the radiance data processing allowing an easily and quickly radiometric calibration. Thanks to the proposed method, an integration time insensitive radiometric calibration is obtained from only two different observed steady and homogeneous thermal conditions (using a black body or equivalent).

Applied Photometry: Review of Retrospective and Reality Part 1: Candela and Watt, from Incandescent Lamp to LED

Photometry is the science of measuring light, which began with a visual comparison of the light of stars, the moon, and the sun with the light of a candle. Today it is a part of optical radiometry, inextricably linked with physical radiation detectors, taking into account the fact that light is actinic radiation, and physical detectors must be actinic in the case of integral measurements. At the same time, optical radiometry has introduced and introducing new technologies into spectral radiometric measurement methods, which, in turn, make it possible to solve the problems of measuring the parameters of actinic radiation by objective physical methods of spectral radiometry, taking into account the weight functions of actinic radiation. The choice between integral and spectral methods is determined by: – The required accuracy of the measurement task to be solved; – Knowledge of the weight functions of actinic radiation; – The quality of correction of radiation receivers for the weight functions of actinic radiation; – Methods for calibrating radiation receivers; – Actinic coefficients of optical radiation receivers (correction coefficients) and the accuracy of their determination; – Technical capabilities of spectral equipment; – Methods and means of spectrometers calibration; – Software for spectral measuring instruments, – Comparative analysis of the accuracy (uncertainty) of measurements by the spectral and integral methods in each individual case. The replacement of traditional sources of general lighting and signaling by radiation sources with LEDs, which have a spectral distribution of light emitting characteristics different from traditional light sources, has raised a number of issues in the metrological support of optical radiometry and applied photometry related to the oneness of the reproduction of units of energy and photometric quantities based on Watt.

Laser light absorption and Brewster angle on liquid metal

Laser light absorption occurs in all laser-based processes and is, therefore, of importance for process simulation input, parameter optimization, and understanding of the occurring phenomena, such as melt pool flow or vaporization effects. Theoretical models were successful in predicting metal absorption for certain cases but often fail in high-temperature situations due to unknown impacts of occurring effects, such as surface irregularities or contaminations. Measuring absorption at high temperatures is challenging, and there are limited literature data available on values further above melting temperatures of metals. In this work, a radiometric measurement method is used to derive absorption values at high temperatures. The results show shifted values from Fresnel predictions and absorption peaks at comparably low incident angles. The decreasing absorption tendency at low incident angles was shown to be possibly induced by multi-interface absorption effects caused by surface layering and Knudsen layer effects. Surface layering was seen to be able to induce a very low Brewster angle comparable to the observations in the measurements and is, therefore, seen as a possible dominant factor in absorption at elevated temperatures.

The distribution of fossil pollen and charcoal in stalagmites

AbstractPollen preserved in caves provides a little-appreciated opportunity to study past vegetation and climate changes in regions where conventional wetland sediments are either unavailable, contain little organic matter, and/or are difficult to date accurately. Most palynology in caves has focused on clastic infill sediments, but pollen preserved in growing speleothems provides important new opportunities to develop vegetation and climatic records that can be dated accurately with radiometric methods. However, when pollen is present in speleothems, concentrations can vary by orders of magnitude, highlighting how little we know about the processes that transport pollen into caves and onto speleothem surfaces, and that determine the pollen's preservation probability. To explore these aspects of speleothem pollen taphonomy, we investigated the distribution of pollen and microscopic charcoal within several stalagmites from southwest Australia. We examined spatial patterns in pollen and charcoal preservation in order to distinguish whether observed gradients result from preservation or are products of systematic transport processes working along stalagmite surfaces. We find that pollen grains and charcoal fragments are located preferentially on the flanks of most stalagmites. This suggests that pollen grain and charcoal deposition on speleothems is influenced by transport and accumulation of detrital debris on growing surfaces. These insights will assist in future sampling campaigns focusing on speleothem pollen and charcoal contents.

Radiometric Mapping for The Identification of Hydrothermally Altered Zones Related to Gold Mineralization in Ife–Ilesa Schist Belt, Southwestern Nigeria

This study presents the interpretation of airborne gamma ray spectrometric data to delineate hydrothermally altered zones related to gold mineralization in the Ife–Ilesa Schist belt. K/eTh, Kd and F–Maps highlighting Potassic alterations related to gold mineralization were processed on the Oasis Montaj software and subsequently integrated using fuzzy logic modeling to produce the hydrothermal alteration map of the study area. The C–A fractal analysis was applied to the final hydrothermal map and was able to classify the study area into background, very low, low, moderate, high and very high alteration. These classes reflect the pervasive hydrothermal alteration style of the study area. The hydrothermally altered areas are evident on granitoids and areas proximal to it indicating that granitoids are proxies of heat source. Occurrence of active mining sites in the area agrees with the generated hydrothermal alteration map of the study area with 81% agreement. It therefore shows that radiometric method is a veritable method in mapping hydrothermal alteration areas. The use of radiometric method only cannot reliably map areas of gold mineralization as mineralization can be associated with several other processes. Hence, other methods involving geochemical and magnetic methods including GIS tools can be employed for further prospecting.

A Review on Measurement of Spectral Directional Emissivity of Microstructured Surfaces in Infrared Wavelength Range

A survey of researches in the field of spectral directional emissivity measurements of microstructured surfaces by using direct and indirect radiometric methods in infrared wavelength range is presented. Nowadays, new concepts of periodic surface microstructures with geometrical dimensions of the same order of magnitude as the thermal radiation wavelengths are becoming one of the attractive methods for controlling spectral radiative properties of a surface like emissivity and reflectivity. Since the resonance effect between the periodic microstructures and the electromagnetic field has become one of the most promising ways to vary optical or radiative properties of the radiating surfaces artificially, in this review paper emphasis is given to the measurement of directional spectral emissivity of microstructured surfaces. A review of many systems is presented that are capable of measuring the spectral directional emissivities of solid surfaces at moderate temperatures. An overview of experimental setups is provided including the reference sources of radiation, the sample clamping and heating, detection systems, methods for the determination of surface temperature and procedures for emissivity evaluation. The paper is focused on methods of finding the emissivity of microstructures. Selected experimental data in the form of graph are presented for various microstructured surfaces.

Preliminary development of emissivity measurement system at low temperature based on radiometric method

Thermal radiation is a major part of heat transfer in cryogenic systems, especially in vacuum environment. The emissivity of materials is an essential factor of thermal radiation, which is difficult to be precisely predicted by theoretical calculation. Thus, the direct experimental measurement becomes an inevitable, reliable method. In this paper, a preliminary emissivity measurement system using the direct radiometric method was designed and built with a G-M (Gifford-McMahon) cryocooler as the cold source. The sample plate in the apparatus can be cooled to 9.2 K, while the sample thermal radiation shield and the optical path cover can respectively reach 46.7 K and 46.9 K. At present stage, MCT (HgCdTe) detector with an effective bandwidth 2–12 μm was used in this system, which achieved the measurements of emissivities of coating Nextel 811–21, 304 stainless steel and G10 composite from 240 K to 300 K. The reliability of the system was verified by comparing the measurement results with the data already published, and the dependence of the emissivities of these materials on temperature are analyzed.

Forecast of the mine workings destruction risks by the radiometric control method

The stress-strain state of the rock mass affects the content of methane gas and radon aerosols in the atmosphere of mine workings. Therefore, combined control of methane gas and radon in mine workings allows us to monitor changes in the state of the rock massif and to take measures in proper time to reduce the risks of the roadway destruction. Forecasting of rock massif and mine roadway dangerous state is based on the determined features of methane gas emission together with radon decay products into the mine roadways radon decay products. Interdependence between the dynamics of changes in the concentration of methane gas and the normalized concentration of radon is established when range of the deviations from the average value is ± 20%. Abrupt spikes at the range above 40% are explained in prone-to-destruction zones of the rock massif. One of the indicators of the rock massif readiness for dynamic manifestations of rock pressure and the destruction of mine roadways can be a decrease in the concentration of radon decay products Po218 below 5%.

Distribution of strontium-90 in soils affected by Fukushima dai-ichi nuclear power station accident in the context of cesium-137 contamination

90Sr and 137Cs activity concentrations were determined by radiometric methods in 76 soil samples (soil, litter, rain gutter deposit, and roadside sediment samples) affected by the Fukushima Dai-ichi Nuclear Power Station (FDNPS) accident and collected from the Fukushima exclusion zone. The 90Sr and 137Cs activity concentrations were in the range of 3 to 1050 Bq kg−1 (median 82 Bq·kg−1) and 0.7 to 6770 kBq·kg−1 (median 890 kBq·kg−1), respectively (decay correction date: March 15, 2011). A strong positive correlation was found between 90Sr and 137Cs activity concentration and higher mobility of 90Sr was confirmed in Japanese soil samples. The activity ratio of 90Sr/137Cs in 85% of all samples was in the range of 5.0 × 10−5 to 5.0 × 10−4 with a median of 1.2 × 10−4. From the activity ratio values it was concluded that the 90Sr released to the atmosphere was only around 0.0003–0.02 PBq which is negligible compared to the Chernobyl accident (∼10 PBq) or other nuclear accident contaminations. From the standpoints of radioecology and radiation safety, 137Cs remains the primary pollutant of the FDNPS accident.

A DATABASE OF NERC RADIOCARBON MEASUREMENTS DETERMINED BY ACCELERATOR MASS SPECTROMETRY

ABSTRACT Radiocarbon (14C) measurements undertaken by the NERC Radiocarbon Laboratory using accelerator mass spectrometry (AMS) are now freely available on a new online database. The data presented covers measurement of the wide range of sample types that are processed for research projects in the fields of Earth and environmental science, supported by the United Kingdom’s Natural Environment Research Council. Sample types within the database include organic remains, soils, sediments, carbonates, dissolved organic and inorganic carbon, and carbon dioxide. Currently, the database contains 14C data for over 2400 individual samples that were measured and reported between 2005 and 2013, but it is envisaged that this will expand considerably as more data are made available. Contextual information such as sampling location and associated publications are provided where available, and searches can be performed on sample location, sample type, project number, and publication code. This new database compliments an existing, publicly available database of measurements performed using radiometric methods by the laboratory which has recently been expanded to present over 2000 measurements. It is hoped that this archive will prove useful to workers in the community who would benefit from greater availability of measurements for particular locations or sample types, and for the purposes of performing meta-analyses, and/or synthesis of larger datasets.

Abandoned farmland detection using single-year satellite images in Japan

Mapping abandoned farmlands' location and spatial pattern is essential for rural planning. Monitoring small abandoned farmland based on dynamic farmland's phenology is challenging to due to conflict between spatial and temporal resolutions of conventional satellite missions. A unique approach that combines satellite constellation imagery with improved automatic radiometric normalization method for more temporally consistent reflectance were proposed. Applying it in Ami-town, Ibaraki Prefecture, Japan, abandoned farmlands were identified with 3-m resolution and a Kappa coefficient of 0.81 based on satellite constellation-based time-series data; however, the discrimination of the degree of abandonment was challenging. Unlike conventional abandoned farmland mapping approaches which targets spatially large area, our approach provides information at small, fragmented and abandoned farmland in East Asia that enables labor-saving monitoring of land use shifts.

Development of a Radiometric Calibration Method for Multispectral Images of Croplands Obtained with a Remote-Controlled Aerial System

A remote sensing (RS) platform consisting of a remote-controlled aerial vehicle (RAV) can be used to monitor crop, environmental conditions, and productivity in agricultural areas. However, the current methods for the calibration of RAV-acquired images are cumbersome. Thus, a calibration method must be incorporated into RAV RS systems for practical and advanced applications. Here, we aimed to develop a standalone RAV RS-based calibration system without the need for calibration tarpaulins (tarps) by quantifying the sensor responses of a multispectral camera, which varies with light intensities. To develop the standalone RAV-based RS calibration system, we used a quadcopter with four propellers, with a rotor-to-rotor length of 46 cm and height of 25 cm. The quadcopter equipped with a multispectral camera with green, red, and near-infrared filters was used to acquire spectral images for formulating the RAV RS-based standardization system. To perform the calibration study process, libraries of sensor responses were constructed using pseudo-invariant tarps according to the light intensities to determine the relationship equations between the two factors. The calibrated images were then validated using the reflectance measured in crop fields. Finally, we evaluated the outcomes of the formulated RAV RS-based calibration system. The results of this study suggest that the standalone RAV RS system would be helpful in the processing of RAV RS-acquired images.

Радіаційно-гігієнічний моніторинг у районі Запорізької АЕС в умовах загрози радіаційної небезпеки

Objective: To assess the results of monitoring radiation indicators of the state of the environment in the Zaporizhzhia region under the threat of a radiation accident at the Zaporizhzhia NPP in order to make decisions regarding the use of countermeasures. Materials and methods: As a result of the analysis of long-term observations, indicators of radioactivity in the event of a radiation accident were determined. More than 21,000 measurements of the gamma background of the territory were carried out in 13 settlements of the Zaporizhzhia region. The dosimetry method was used to measure the power of the equivalent dose. The radiometric method was used to study the total radioactivity of drinking water from the water supply network. 21 samples were taken. The study of the total beta activity of atmospheric precipitation and settling dust was carried out by the sedimentation method. A total of 34 samples were examined. Results: As a result of the conducted research, it was recorded that the radiation component in the territory of the region did not change – gamma background levels remained within the range of long-term observations of 10-12 μR•h-1. It was established that the total alpha and beta activity of drinking water meets the requirements of the current legislation. The results of the studies of atmospheric sediments and settled dust show that there is no increase in the total beta activity in the atmosphere compared to the average long-term indicator observed in the period before 1986.