scholarly journals Long-term repeatability and interlaboratory reproducibility of high-precision ID-TIMS U-Pb geochronology

2021 ◽  
Author(s):  
Urs Schaltegger ◽  
Maria Ovtcharova ◽  
Sean P. Gaynor ◽  
Blair Schoene ◽  
Jörn-Frederik Wotzlaw ◽  
...  
Keyword(s):  
High Precision ◽  
Age Determination ◽  
Interlaboratory Reproducibility

Age determination of minerals using the U-Pb technique is widely used to quantify time in Earth’s history. A number of geochronology laboratories produce the highest precision U-Pb dates employing the...

High-precision age determination of Holocene samples by radiocarbon dating with accelerator mass spectrometry at Nagoya University

2016 ◽  
Vol 397 ◽  
pp. 250-257 ◽  
Author(s):  
Toshio Nakamura ◽  
Kimiaki Masuda ◽  
Fusa Miyake ◽  
Masataka Hakozaki ◽  
Katsuhiko Kimura ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Precision ◽  
Accelerator Mass Spectrometry ◽  
Radiocarbon Dating ◽  
Age Determination

scholarly journals Honey as an indicator of long-term environmental changes: MP-AES analysis coupled with 14C-based age determination of Hungarian honey samples

2020 ◽  
Vol 736 ◽  
pp. 139686 ◽  
Author(s):  
Tamás Varga ◽  
Zsófi Sajtos ◽  
Zita Gajdos ◽  
A.J. Timothy Jull ◽  
Mihály Molnár ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Age Determination

The prediction service of H. M. Nautical Almanac Office

1958 ◽  
Vol 248 (1252) ◽  
pp. 45-48 ◽  
Keyword(s):  
High Precision ◽  
Artificial Satellite ◽  
Artificial Satellites ◽  
Atmospheric Drag ◽  
The Earth ◽  
Professional Interest ◽  
Data Centres ◽  
Nautical Almanac

Most people think that close artificial satellites of the earth fall directly within the field of responsibility of H. M. Nautical Almanac Office. This is not so. The Office, and the corresponding ephemeris offices in other countries, are concerned primarily with long-term, high-precision theories and predictions of heavenly bodies; comets and meteors are excluded from our field and are dealt with com­petently by others, mainly by amateurs. Our professional interest will be aroused when an artificial satellite is launched into an orbit with perigee so high above the earth’s surface that atmospheric drag is very small; such an object, with a life of ten years or more, will be of definite astronomical importance. The ephemeris offices will then produce, and publish, accurate ephemerides based on a combina­tion of theory and observation to assist in the comparison of theory with observa­tion. It is conceivable that such satellites will provide rapid and accurate methods for the determination of the second of ephemeris time, now accepted as the funda­mental standard of time. Navigational applications must also be considered. For the two satellites so far (29 November) launched by U. S. S. R., the Office has been compelled, through limitations of staff and equipment, to confine its work to ( a ) a prediction service, and ( b ) the collection and copying of observations and their transmission (in due course) to I. G. Y. World Data Centres, and possibly directly to other institutes.

On effects of non-systematic reflections on weak-beam images of partial dislocations

1991 ◽  
Vol 49 ◽  
pp. 688-689
Author(s):  
K. Z. Botros ◽  
S. S. Sheinin
Keyword(s):  
High Precision ◽  
Stacking Fault ◽  
Important Application ◽  
Stacking Fault Energy ◽  
Sharp Peak ◽  
Weak Beam ◽  
Partial Dislocations ◽  
Deviation Parameter ◽  
Beam Diffraction

The main features of weak beam images of dislocations were first described by Cockayne et al. using calculations of intensity profiles based on the kinematical and two beam dynamical theories. The feature of weak beam images which is of particular interest in this investigation is that intensity profiles exhibit a sharp peak located at a position very close to the position of the dislocation in the crystal. This property of weak beam images of dislocations has an important application in the determination of stacking fault energy of crystals. This can easily be done since the separation of the partial dislocations bounding a stacking fault ribbon can be measured with high precision, assuming of course that the weak beam relationship between the positions of the image and the dislocation is valid. In order to carry out measurements such as these in practice the specimen must be tilted to "good" weak beam diffraction conditions, which implies utilizing high values of the deviation parameter Sg.

Preparation And elemental analysis of ancient fibers

1987 ◽  
Vol 45 ◽  
pp. 410-411
Author(s):  
Allen Angel ◽  
Kathryn A. Jakes
Keyword(s):  
Cross Sections ◽  
Physical Structure ◽  
Energy Dispersive ◽  
Archaeological Sites ◽  
X Ray ◽  
Long Term Storage ◽  
Backscattered Electron ◽  
Electron Imaging

Fabrics recovered from archaeological sites often are so badly degraded that fiber identification based on physical morphology is difficult. Although diagenetic changes may be viewed as destructive to factors necessary for the discernment of fiber information, changes occurring during any stage of a fiber's lifetime leave a record within the fiber's chemical and physical structure. These alterations may offer valuable clues to understanding the conditions of the fiber's growth, fiber preparation and fabric processing technology and conditions of burial or long term storage (1).Energy dispersive spectrometry has been reported to be suitable for determination of mordant treatment on historic fibers (2,3) and has been used to characterize metal wrapping of combination yarns (4,5). In this study, a technique is developed which provides fractured cross sections of fibers for x-ray analysis and elemental mapping. In addition, backscattered electron imaging (BSI) and energy dispersive x-ray microanalysis (EDS) are utilized to correlate elements to their distribution in fibers.

Improvement Of Curvilinear Diagrams Of Concrete Deformation

2019 ◽  
pp. 99-104
Keyword(s):  
Reinforced Concrete ◽  
Peak Load ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Deformation Model ◽  
Reinforced Concrete Structures ◽  
Significant Difference ◽  
Deformation Diagrams

Problems when calculating reinforced concrete structures based on the concrete deformation under compression diagram, which is presented both in Russian and foreign regulatory documents on the design of concrete and reinforced concrete structures are considered. The correctness of their compliance for all classes of concrete remains very approximate, especially a significant difference occurs when using Euronorm due to the different shape and sizes of the samples. At present, there are no methodical recommendations for determining the ultimate relative deformations of concrete under axial compression and the construction of curvilinear deformation diagrams, which leads to limited experimental data and, as a result, does not make it possible to enter more detailed ultimate strain values into domestic standards. The results of experimental studies to determine the ultimate relative deformations of concrete under compression for different classes of concrete, which allowed to make analytical dependences for the evaluation of the ultimate relative deformations and description of curvilinear deformation diagrams, are presented. The article discusses various options for using the deformation model to assess the stress-strain state of the structure, it is concluded that it is necessary to use not only the finite values of the ultimate deformations, but also their intermediate values. This requires reliable diagrams "s–e” for all classes of concrete. The difficulties of measuring deformations in concrete subjected to peak load, corresponding to the prismatic strength, as well as main cracks that appeared under conditions of long-term step loading are highlighted. Variants of more accurate measurements are proposed. Development and implementation of the new standard GOST "Concretes. Methods for determination of complete diagrams" on the basis of the developed method for obtaining complete diagrams of concrete deformation under compression for the evaluation of ultimate deformability of concrete under compression are necessary.

Analysis of Fibronectin and TGF-β1 Immunoexpression to Determination of Wound Vitality in Wistar Rats (Rattus norvegicus)

2015 ◽  
Vol 1 (1) ◽  
Author(s):  
Nita Novita ◽  
Hasrayati Agustina ◽  
Bethy S. Hernowo ◽  
Abdul H. Hassan
Keyword(s):  
Rattus Norvegicus ◽  
Wistar Rats ◽  
Age Determination ◽  
Scientific Field ◽  
Wound Age ◽  
Forensic Practice ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
Tgf Β1

Wound examination is indispensable in forensic practice. The scientific field of wound age determination has advanced progressively during recent years.The purpose of this study was to determine the differences of fibronectin and TGF-β1 expression in both antemortem and postmortem wounds. This study was an experimental with completely randomized design.  The skin wounds (vital and postmortem) were taken from fourty Wistar rats and divided into 10 groups of rats. Immunohistochemical staining was performed to determine the differences between antemortem and postmortem wounds. The result showed that in 30 minutes after antemortem wound infliction, all of samples showed weak reactivity for fibronectin and TGF-β1 (100%).  In first hour after wound infliction, 3 samples (75%) showed weakly positive and 1 sample (25%) strongly positive for fibronectin and TGF-β1.  In 2 hour after wound infliction, 1 sample (25%) showed weakly positive and 3 sample (75%) strongly positive for fibronectin and TGF-β1.  In 3 and 4 hour after wound infliction, all of samples strongly positive for fibronectin and TGF-β1.  In postmortem wound, all of samples showed negativity for fibronectin and TGF-β1. In conclusion, fibronectin and TGF-β1 may be useful in the determination of wound vitality. Keywords: wound, fibronectin, TGF-β1, vitality

Sign in / Sign up

Export Citation Format

Share Document