scholarly journals Measuring impurity content in pipelines by positron annihilation

2020 ◽  
pp. 002029402096859
Author(s):  
Yahan Yu ◽  
Min Zhao ◽  
Jun Xu ◽  
Min Yao ◽  
Ruipeng Guo ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Measurement Accuracy ◽  
Impurity Content ◽  
Detection Accuracy ◽  
Detection Scheme ◽  
Oil Pipelines ◽  
Good Consistency ◽  
Piping Systems ◽  
Test Result

γ photon pairs produced by positron annihilation can penetrate metals well; thus, they can be used for nondestructive detection of the inner state of metal pipelines. An experimental device is designed to simulate the working state of lube oil pipelines and inject nuclide into it. A symmetrical structure and a ratio algorithm are proposed considering the effects of various factors. Two sensors with good consistency are used to record the number of γ photon events in liquids with and without impurities. The ratio of the recorded events of reference and impurity sensors is taken as the test result of impurity content. The advantage of the method proposed in this paper is that it can eliminate the environmental error and inconsistency of the sensors by using ratio calculation and improve the measurement accuracy. Experimental results show that the proposed detection scheme and algorithm can well detect impurity content, including metal, in various pipelines. The detection accuracy of matched sensors can exceed 2%. Detected impurities are not limited to metal particles. Thus, the proposed method can be applied to in situ and online detection of impurities in oil piping systems equipped with engines.

Preliminary Positron Lifetime Results on Free Volumes in Cyclodextrins

2010 ◽  
Vol 666 ◽  
pp. 99-102 ◽  
Author(s):  
Maria Fatima Ferreira Marques ◽  
A.M.G. Moreira Da Silva ◽  
P.M. Gordo ◽  
Z. Kajcsos
Keyword(s):  
Positron Annihilation ◽  
Free Volume ◽  
Positron Lifetime ◽  
Positron Annihilation Lifetime Spectroscopy ◽  
Positron Source ◽  
Lifetime Component ◽  
Positron Annihilation Lifetime ◽  
Long Lifetime

Positron annihilation lifetime spectroscopy was used to study the free-volume parameters in various pure -, - and -cyclodextrins samples and, in the case of β-cyclodextrin, with inclusion of S-carvone and thymoquinone. The results clearly indicate the presence of long lifetime components related to Ps-formation. The data show that the addition of S-carvone to β-cyclodextrin results in a decrease of o-Ps lifetime that we ascribe to a reduction of free volume holes from 81.8 to 63.7 Å3. The long lifetime component disappears when thymoquinone is added to -cyclodextrin, indicating this substance acts as an o-Ps quencher. For all samples studied, a decrease in the long lifetime component values was observed with increasing source in situ time, a result that might be attributed to the irradiation of the sample by the 22Na positron source.

scholarly journals 2D In Situ Method for Measuring Plant Leaf Area with Camera Correction and Background Color Calibration

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Li-fen Tu ◽  
Qi Peng ◽  
Chun-sheng Li ◽  
Aiqun Zhang
Keyword(s):  
Leaf Area ◽  
Measurement Accuracy ◽  
Area Measurement ◽  
Background Color ◽  
Correction Algorithm ◽  
Plant Leaf ◽  
Color Calibration ◽  
In Situ Method ◽  
Environmental Adaptability

In order to measure the plant leaf area conveniently and quickly in an indoor laboratory and outdoor field, a set of scaffold leaf area measurement systems was designed and manufactured. A 2D in situ method for measuring plant leaf area with camera correction and background color calibration was proposed. The method integrates three subalgorithms: fast calibration and distortion correction algorithm, background color calibration algorithm, and edge error correction algorithm. At the same time, the Visual Studio 2015 and OpenCV 3.4.0 were used to develop and test the algorithm. In order to verify the measurement speed and environmental adaptability of the system, the test was carried out in the complex light disturbance outdoors, and the results were consistent with those in the room. In order to verify the measurement accuracy of the system, this method was used to measure the standard rectangular gauge block of known area and the real leaf area, respectively, and its data were compared with the data measured by Wanshen LA-S plant image analyzer. The results show that both methods have a good stability, and the algorithm proposed in this paper performs better in measurement accuracy and environmental adaptability.

scholarly journals Chlorine activation by N<sub>2</sub>O<sub>5</sub>: simultaneous, in situ detection of ClNO<sub>2</sub> and N<sub>2</sub>O<sub>5</sub> by chemical ionization mass spectrometry

2009 ◽  
Vol 2 (1) ◽  
pp. 119-151 ◽  
Author(s):  
J. P. Kercher ◽  
T. P. Riedel ◽  
J. A. Thornton
Keyword(s):  
Mass Spectrometry ◽  
Detection Limit ◽  
Chemical Ionization ◽  
Ionization Mass Spectrometry ◽  
Chemical Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Nitrate Anion ◽  
Detection Scheme ◽  
In Situ Detection

Abstract. We report a new method for the simultaneous in situ detection of nitryl chloride (ClNO2) and dinitrogen pentoxide (N2O5) using chemical ionization mass spectrometry (CIMS). The technique relies on the formation and detection of iodide ion-molecule clusters, I(ClNO2)− and I(N2O5)−. The novel N2O5 detection scheme is direct. It does not suffer from high and variable chemical interferences, which are associated with the typical method of nitrate anion detection. We address the role of water vapor, electric field strength, and instrument zero determinations, which influence the overall sensitivity and detection limit of this method. For both species, the method demonstrates high sensitivity (>1 Hz/pptv), precision (~10% for 100 pptv in 1 s), and accuracy (~20%), the latter ultimately determined by the nitrogen dioxide (NO2) cylinder calibration standard and characterization of inlet effects. For the typically low background signals (<10 Hz) and high selectivity, we estimate signal-to-noise (S/N) ratios of 2 for 1 pptv in 60 s averages, but uncertainty associated with the instrumental zero currently leads to an ultimate detection limit of ~5 pptv for both species. We validate our approach for the simultaneous in situ measurement of ClNO2 and N2O5 while on board the Research Vessel (RV) Knorr as part of the ICEALOT 2008 Field Campaign.

scholarly journals Photochromic YOxHy Thin Films Examined by in situ Positron Annihilation Spectroscopy

2020 ◽  
Vol 137 (2) ◽  
pp. 205-208 ◽  
Author(s):  
S.W.H. Eijt ◽  
T.W.H. de Krom ◽  
D. Chaykina ◽  
H. Schut ◽  
G. Colombi ◽  
...  
Keyword(s):  
Thin Films ◽  
Positron Annihilation ◽  
Positron Annihilation Spectroscopy

scholarly journals Positron Annihilation Lifetime in situ Study of Deformed Polyolefin Elastomers

2005 ◽  
Vol 107 (5) ◽  
pp. 837-841 ◽  
Author(s):  
K. Krzemień ◽  
J. Kansy ◽  
J.E. Frąckowiak
Keyword(s):  
Positron Annihilation ◽  
Positron Annihilation Lifetime ◽  
In Situ Study

scholarly journals On The Estimation of Temporal Changes of Snow Water Equivalent by Spaceborne Sar Interferometry: A New Application for the Sentinel-1 Mission

2019 ◽  
Vol 67 (1) ◽  
pp. 93-100 ◽  
Author(s):  
Vasco Conde ◽  
Giovanni Nico ◽  
Pedro Mateus ◽  
João Catalão ◽  
Anna Kontu ◽  
...  
Keyword(s):  
Measurement Accuracy ◽  
Snow Water Equivalent ◽  
Temporal Variations ◽  
Sar Interferometry ◽  
Synthetic Aperture ◽  
Snow Layer ◽  
Illumination Condition ◽  
Interferometric Phase ◽  
Snow Water

Abstract In this work we present a methodology for the mapping of Snow Water Equivalent (SWE) temporal variations based on the Synthetic Aperture Radar (SAR) Interferometry technique and Sentinel-1 data. The shift in the interferometric phase caused by the refraction of the microwave signal penetrating the snow layer is isolated and exploited to generate maps of temporal variation of SWE from coherent SAR interferograms. The main advantage of the proposed methodology with respect to those based on the inversion of microwave SAR backscattering models is its simplicity and the reduced number of required in-situ SWE measurements. The maps, updated up to every 6 days, can attain a spatial resolution up to 20 m with sub-centimetre ΔSWE measurement accuracy in any weather and sun illumination condition. We present results obtained using the proposed methodology over a study area in Finland. These results are compared with in-situ measurements of ΔSWE, showing a reasonable match with a mean accuracy of about 6 mm.

scholarly journals In situ continuous visible and near-infrared spectroscopy of an alpine snowpack

2017 ◽  
Vol 11 (3) ◽  
pp. 1091-1110 ◽  
Author(s):  
Marie Dumont ◽  
Laurent Arnaud ◽  
Ghislain Picard ◽  
Quentin Libois ◽  
Yves Lejeune ◽  
...  
Keyword(s):  
Liquid Water ◽  
Near Infrared ◽  
Winter Season ◽  
Impurity Content ◽  
Saharan Dust ◽  
Infrared Range ◽  
Snow Surface ◽  
Surface Slope ◽  
Near Infrared Range

Abstract. Snow spectral albedo in the visible/near-infrared range has been continuously measured during a winter season at Col de Porte alpine site (French Alps; 45.30° N, 5.77° E; 1325 m a.s.l.). The evolution of such alpine snowpack is complex due to intensive precipitation, rapid melt events and Saharan dust deposition outbreaks. This study highlights that the resulting intricate variations of spectral albedo can be successfully explained by variations of the following snow surface variables: specific surface area (SSA) of snow, effective light-absorbing impurities content, presence of liquid water and slope. The methodology developed in this study disentangles the effect of these variables on snow spectral albedo. The presence of liquid water at the snow surface results in a spectral shift of the albedo from which melt events can be identified with an occurrence of false detection rate lower than 3.5 %. Snow SSA mostly impacts spectral albedo in the near-infrared range. Impurity deposition mostly impacts the albedo in the visible range but this impact is very dependent on snow SSA and surface slope. Our work thus demonstrates that the SSA estimation from spectral albedo is affected by large uncertainties for a tilted snow surface and medium to high impurity contents and that the estimation of impurity content is also affected by large uncertainties, especially for low values below 50 ng g−1 black carbon equivalent. The proposed methodology opens routes for retrieval of SSA, impurity content, melt events and surface slope from spectral albedo. However, an exhaustive accuracy assessment of the snow black properties retrieval would require more independent in situ measurements and is beyond the scope of the present study. This time series of snow spectral albedo nevertheless already provides a new insight into our understanding of the evolution of snow surface properties.

Positron Lifetime Calculation for Plastic Deformed Nanocrystalline Copper

2017 ◽  
Vol 373 ◽  
pp. 31-34
Author(s):  
Kai Zhou ◽  
Ting Zhang
Keyword(s):  
Positron Annihilation ◽  
Deformation Mechanism ◽  
Positron Lifetime ◽  
Experimental Information ◽  
Point Of View ◽  
Nanocrystalline Copper ◽  
Mean Grain Size ◽  
Positron Lifetimes ◽  
Boundary Deformation

Positron lifetime calculation has been performed on a computer-generated nanocrystalline copper with a mean grain size of 9.1 nm during its deformation. For the undeformed and deformed nanocrystalline copper, calculated positron lifetimes are around 157 ps which come from the positron annihilation in the free volume in grain boundaries. Due to the grain-boundary deformation mechanism, no vacancies or vacancy clusters will be induced in grains during the plastic deformation of the nanocrystalline copper, which is different to the deformation of the conventional polycrystal. From this point of view, in-situ positron annihilation measurements can provide important experimental information on the deformation mechanism of nanocrystalline metals.

scholarly journals An improved transmitter system to accurately measure wet-bulb temperature of air

2019 ◽  
Vol 52 (7-8) ◽  
pp. 1002-1007
Author(s):  
Liangwen Yan ◽  
Peng Yu ◽  
Sijung Hu ◽  
Qiu Gao ◽  
Wei Li ◽  
...  
Keyword(s):  
Real Time ◽  
Latent Heat ◽  
Measurement Accuracy ◽  
Cost Effective ◽  
Mean Value ◽  
Experimental Results ◽  
Iteration Algorithm ◽  
Good Consistency ◽  
The Mean ◽  
Good Agreement

A cost-effective measurement of wet-bulb temperature of air has great benefits to fulfill a growing demand of industry, cultivation agriculture, and medication. Applying an appropriate algorithm to wet-bulb temperature of air measurement can effectively improve the accuracy and speed of its measurement. The study aims to research how an improved transmitter system along with the latent heat–based iteration algorithm is used to precisely measure wet-bulb temperature of air. The work consists of (1) simulation of the iteration algorithm and (2) validation via experimental protocol. The simulation results through latent heat–based iteration algorithm were in good agreement ( R2≥ 0.99) with the reference. The performance of the improved wet-bulb temperature of air transmitter system was tested by a latent heat–based iteration algorithm experimental setup. The experimental results demonstrate that the improved wet-bulb temperature of air in a good consistency with commercial wet-bulb temperature of air in a range of temperature (15°C–34°C) and relative humidity (28.8%–76.2%). The Bland–Altman plot also shows that the mean value and the standard deviation of the differences between these two systems are 0.14°C and 0.29°C, respectively, which indicates that the improved wet-bulb temperature of air has a good agreement as well. Compared with the commercial wet-bulb temperature of air transmitter system, an advanced processor (STM32F103C8T6) and real-time operating system was applied in the improved wet-bulb temperature of air transmitter system. The experimental results show that its measurement accuracy is closer to the previous study. This study provides an alternative and cost-effective solution to accurately and real-time measure wet-bulb temperature of air.

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