scholarly journals Radiocarbon Variations from Tasmanian Conifers: First Results from Late Pleistocene and Holocene Logs

Radiocarbon ◽  
1992 ◽  
Vol 34 (3) ◽  
pp. 806-817 ◽  
Author(s):  
Mike Barbetti ◽  
Trevor Bird ◽  
George Dolezal ◽  
Gillian Taylor ◽  
Roger Francey ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Late Pleistocene ◽  
Conifer Species ◽  
Calibration Curves ◽  
Bristlecone Pine ◽  
First Results ◽  
Lagarostrobos Franklinii ◽  
Zero Offset ◽  
Floodplain Sediments ◽  
Good Agreement

Dendrochronological studies have begun on two conifer species in the Stanley River area of western Tasmania. The chronology extends to 273 BC for Huon pine (Lagarostrobos franklinii) and to AD 1450 for celery-top pine (Phyllocladus aspleniifolius). Apart from living or recently felled trees, sections have been taken from 58 logs preserved in floodplain sediments. Two of these logs have late Pleistocene ages, centered around 13.0 and 12.7 k 14C yr bp. Four logs are between 8 and 9 ka BP, and one is centered at 7.3 ka bp. The remaining logs have various ages between 6.2 ka BP and the present. 14C measurements have been performed on decadal samples from the two late Pleistocene logs, providing short (260-yr) records of atmospheric 14C variations when plotted against individual ring numbers. Decadal measurements on the 7300-yr-old log have been wiggle-matched with 14C calibration curves from German oak and bristlecone pine. Measurements for the period, AD 1600–1800, show good agreement with northern hemisphere results, and a nearly zero offset between the hemispheres.

scholarly journals Radiocarbon Variations from Tasmanian Conifers: Results from Three Early Holocene Logs

Radiocarbon ◽  
1995 ◽  
Vol 37 (2) ◽  
pp. 361-369 ◽  
Author(s):  
Mike Barbetti ◽  
Trevor Bird ◽  
George Dolezal ◽  
Gillian Taylor ◽  
Roger Francey ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Calibration Curve ◽  
The Other ◽  
Early Holocene ◽  
Conifer Species ◽  
Middle Holocene ◽  
Calibration Curves ◽  
Lagarostrobos Franklinii ◽  
Floodplain Sediments ◽  
Good Coverage

Dendrochronological studies are being carried out on two conifer species in the Stanley River area of western Tasmania. The chronology for Huon pine (Lagarostrobos franklinii), with living trees up to 1400 yr old, extends back to 571 bc. Living celery-top pine (Phyllocladus aspleniifolius) trees are up to 500 yr old. Apart from living or recently felled trees, sections have been taken from 350 subfossil logs preserved in floodplain sediments. They range in age from >38 ka to modern, with good coverage for the periods 9–3.5 ka and from 2.5 ka to the present. We report here on 14C measurements of decadal samples from three early Holocene logs, between 10 and 9 ka bp, providing short (ca. 300-yr) records of atmospheric 14C variations when plotted against ring numbers. The southern hemisphere data from Tasmania can be compared and wiggle-matched with published 14C calibration curves from German oak and pine. One set of measurements covers the period, ca. 9280–8990 cal bp, overlapping the link between the Hohenheim “Main 9” and middle Holocene master oak chronologies. The other sets of measurements from Tasmania coincide; they span the period, ca. 9840–9480 cal bp, overlapping the end of the German Preboreal pine and the beginning of the oak chronologies. Our measurements confirm that this part of the calibration curve is a gently sloping 14C-age plateau (ca. 8900–8700 bp, between 10,000 and 9500 cal bp), and suggest interhemispheric 14C differences close to zero.

scholarly journals First results of low frequency electromagnetic wave detector of TC-2/Double Star program

2005 ◽  
Vol 23 (8) ◽  
pp. 2803-2811 ◽  
Author(s):  
J. B. Cao ◽  
Z. X. Liu ◽  
J. Y. Yang ◽  
C. X. Yian ◽  
Z. G. Wang ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Geomagnetic Storms ◽  
Low Frequency ◽  
Wave Detector ◽  
Ion Cyclotron Waves ◽  
Satellite Platform ◽  
Ion Cyclotron ◽  
First Results

Abstract. LFEW is a low frequency electromagnetic wave detector mounted on TC-2, which can measure the magnetic fluctuation of low frequency electromagnetic waves. The frequency range is 8 Hz to 10 kHz. LFEW comprises a boom-mounted, three-axis search coil magnetometer, a preamplifier and an electronics box that houses a Digital Spectrum Analyzer. LFEW was calibrated at Chambon-la-Forêt in France. The ground calibration results show that the performance of LFEW is similar to that of STAFF on TC-1. The first results of LFEW show that it works normally on board, and that the AC magnetic interference of the satellite platform is very small. In the plasmasphere, LFEW observed the ion cyclotron waves. During the geomagnetic storm on 8 November 2004, LFEW observed a wave burst associated with the oxygen ion cyclotron waves. This observation shows that during geomagnetic storms, the oxygen ions are very active in the inner magnetosphere. Outside the plasmasphere, LFEW observed the chorus on 3 November 2004. LFEW also observed the plasmaspheric hiss and mid-latitude hiss both in the Southern Hemisphere and Northern Hemisphere on 8 November 2004. The hiss in the Southern Hemisphere may be the reflected waves of the hiss in the Northern Hemisphere.

scholarly journals A wireless subglacial probe for deep ice applications

2012 ◽  
Vol 58 (211) ◽  
pp. 841-848 ◽  
Author(s):  
C.J.P.P. Smeets ◽  
W. Boot ◽  
A. Hubbard ◽  
R. Pettersson ◽  
F. Wilhelms ◽  
...  
Keyword(s):  
Water Pressure ◽  
Greenland Ice Sheet ◽  
Depth Range ◽  
Measured Temperature ◽  
Transmission Power ◽  
The West ◽  
System A ◽  
Antenna Type ◽  
First Results ◽  
Good Agreement

AbstractWe present the design and first results from two experiments using a wireless subglacial sensor system (WiSe) that is able to transmit data through 2500 m thick ice. Energy consumption of the probes is minimized, enabling the transmission of data for at least 10 years. In July 2010 the first prototype of the system was used to measure subglacial pressure at the base and a temperature profile consisting of 23 probes in two 600 m deep holes at Russell Glacier, a land-terminating part of the West Greenland ice sheet near Kangerlussuaq. The time series of subglacial pressure show very good agreement between data from the WiSe system and the wired reference system. The wireless-measured temperature data were validated by comparison with the theoretical decrease of melting point with water pressure inside the water-filled hole directly after installation. To test the depth range of the WiSe system a second experiment using three different probe types and two different surface antennas was performed inside the 2537 m deep hole at NEEM. It is demonstrated that, with the proper combination of transmission power and surface antenna type, the WiSe system transmits data through 2500 m thick ice.

scholarly journals Single-sided NMR for the measurement of the degree of cross-linking and curing

2018 ◽  
Vol 7 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Norbert Halmen ◽  
Christoph Kugler ◽  
Eduard Kraus ◽  
Benjamin Baudrit ◽  
Thomas Hochrein ◽  
...  
Keyword(s):  
Relaxation Times ◽  
Curing Kinetics ◽  
Cross Linking ◽  
Scanning Calorimetry ◽  
First Results ◽  
Non Destructive ◽  
Kinetics Of ◽  
Good Agreement

Abstract. The degree of cross-linking and curing is one of the most important values concerning the quality of cross-linked polyethylene (PE-X) and the functionality of adhesives and resin-based components. Up to now, the measurement of this property has mostly been time-consuming and usually destructive. Within the shown work the feasibility of single-sided nuclear magnetic resonance (NMR) for the non-destructive determination of the degree of cross-linking and curing as process monitoring was investigated. First results indicate the possibility of distinguishing between PE-X samples with different degrees of cross-linking. The homogeneity of the samples and the curing kinetics of adhesives can also be monitored. The measurements show good agreement with reference tests (wet chemical analysis, differential scanning calorimetry, dielectric analysis). Furthermore, the influence of sample temperature on the characteristic relaxation times can be observed.

An Additively Manufactured Four Sensor Fast Response Aerodynamic Probe

2020 ◽  
Author(s):  
Alexandros Chasoglou ◽  
Panagiotis Tsirikoglou ◽  
Anestis Kalfas ◽  
Reza Abhari
Keyword(s):  
First Generation ◽  
Incidence Angle ◽  
Three Dimensional ◽  
Fast Response ◽  
Design Development ◽  
Free Jets ◽  
Axisymmetric Jet ◽  
First Results ◽  
Binder Jetting ◽  
Good Agreement

Abstract The current work describes the design, development and testing of a miniature fast response aerodynamic probe (FRAP) with 4 sensors (4S), able to perform measurements in unsteady three-dimensional flow field. Moreover, the calibration and first results with the newly developed probe is also provided. The miniature FRAP-4S demonstrates a 3 mm tip diameter, which represents a 25% reduction in diameter size, in comparison to a first generation FRAP-4S, without any loss in terms of measurement bandwidth. The 3 mm outer casing of the probe is additively manufactured with a high-precision binder jetting technique. In terms of aerodynamic performance, the probe demonstrates high angular sensitivity up to at least ± 18° incidence angle in both directions. To evaluate the measurement accuracy of the newly developed FRAP-4S, measurements are performed at the Laboratory for Energy Conversion (LEC) in both a round axisymmetric jet and an one-and-a-half stage, unshrouded and highly-loaded axial turbine configuration. Turbulence measurements performed with the miniature FRAP-4S are compared against hot-wire studies in round free-jets found in the literature. Good agreement in both trends but also absolute values is demonstrated. Moreover, the performance of the probe is compared against traditional instrumentation developed at LEC, namely miniature pneumatic and FRAP-2S probes. The results indicate that the FRAP-4S, despite its larger size in comparison to the other probes tested, can resolve the main flow patterns, while the highest deviations occur in the presence of highly skewed and sheared flows. Furthermore, the additively manufactured probe was proven to be robust after more than 50 hours of testing in representative turbine environment configuration. Finally, it should be highlighted that the newly developed FRAP reduces measurement time by a factor of three in comparison to FRAP-2S, which directly translates to reduced development time and thus cost, during turbomachinery development phase.

scholarly journals Surface Magnetic Field Measurements in Hot Chemically Peculiar Stars

1988 ◽  
Vol 132 ◽  
pp. 313-316
Author(s):  
Pierre. Didelon
Keyword(s):  
Magnetic Field ◽  
Field Measurements ◽  
Surface Magnetic Field ◽  
Surface Field ◽  
Chemically Peculiar ◽  
Peculiar Stars ◽  
Magnetic Field Measurements ◽  
First Results ◽  
Chemically Peculiar Stars ◽  
Good Agreement

The first results of magnetic field measurements are presented here for HD 187474, a slowly rotating Ap star. From resolved Zeeman pattern the strength of the field and its mean inclination were obtained. From differential magnetic broadening a second value of the field strength has been deduced, which is compatible with the previous one. The “Robinson” method has been tested and a good agreement is found between observed and calculated Zeeman broadening of FeII lines. This method can therefore certainly be used to measure the surface field in slow rotating chemically peculiar stars.

The First Results of Tephrochronological Study of Late Pleistocene–Holocene Volcanic Eruptions in the Zhom–Bolok River Valley (Eastern Sayan)

2019 ◽  
Vol 486 (1) ◽  
pp. 503-506 ◽  
Author(s):  
A. A. Shchetnikov ◽  
E. V. Bezrukova ◽  
E. V. Kerber ◽  
O. Yu. Belozerova ◽  
M. I. Kuzmin ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Volcanic Eruptions ◽  
River Valley ◽  
First Results ◽  
Eastern Sayan

scholarly journals Optimized Model-Functions for CCD-Camera Based Astrometric Plate Measurements

1994 ◽  
Vol 161 ◽  
pp. 288-290
Author(s):  
L. Winter
Keyword(s):  
Ccd Camera ◽  
Detailed Understanding ◽  
New Models ◽  
First Results ◽  
Optimized Model ◽  
Measuring Machine ◽  
Imaging Properties ◽  
Modelling Methods ◽  
Good Agreement

While digitizing the first 1500 photographic plates (astrograph plates and prime focus plates of various telescopes) using our CCD-based measuring machine, we gained a detailed understanding of the properties of the digitized stellar images. These images are different from those obtained by digitizing photographic plates with microdensitometers and similar scanners. Therefore it was necessary to reject the modelling methods given in the literature and compose new models that describe the stellar images more accurately. First results of simulating the whole imaging process, starting with the atmosphere, aberrations of the telescope, etc., and ending by including the imaging-properties of our measuring machine, show good agreement with the measured images as well as the modelling functions.

First results from the XMCD facility at the Energy-Dispersive EXAFS beamline of the Indus-2 synchrotron source

2019 ◽  
Vol 26 (2) ◽  
pp. 445-449
Author(s):  
N. Patra ◽  
U. G. P. S. Sachan ◽  
S. SundarRajan ◽  
Sanjay Malhotra ◽  
Vijay Harad ◽  
...  
Keyword(s):  
Magnetic Circular Dichroism ◽  
Energy Dispersive ◽  
X Rays ◽  
Beam Direction ◽  
Synchrotron Source ◽  
X Ray ◽  
Synchrotron Beam ◽  
First Results ◽  
Set Up ◽  
Good Agreement

Setting up of the X-ray Magnetic Circular Dichroism (XMCD) measurement facility with hard X-rays at the Energy-Dispersive EXAFS beamline (BL-08) at the Indus-2 synchrotron source is reported. This includes the design and development of a water-cooled electromagnet having a highest magnetic field of 2 T in a good field volume of 125 mm3 and having a 10 mm hole throughout for passage of the synchrotron beam. This also includes the development of an (X–Z–θ) motion stage for the heavy electromagnet for aligning its axis and the beam hole along the synchrotron beam direction. Along with the above developments, also reported is the first XMCD signal measured on a thick Gd film in the above set-up which shows good agreement with the reported results. This is the first facility to carry out XMCD measurement with hard X-rays in India.

RAP — ACOUSTIC DETECTION OF PARTICLES: FIRST RESULTS AT 4.2 K

2005 ◽  
Vol 20 (29) ◽  
pp. 7054-7056
Author(s):  
C. LIGI ◽  
M. BASSAN ◽  
S. BERTOLUCCI ◽  
B. BUONOMO ◽  
E. COCCIA ◽  
...  
Keyword(s):  
Cryogenic Temperature ◽  
Dilution Refrigerator ◽  
Test Facility ◽  
Acoustic Detection ◽  
Beam Test ◽  
Mechanical Vibrations ◽  
First Results ◽  
Different Temperatures ◽  
First Time ◽  
Good Agreement

RAP (Rivelazione Acustica di Particelle) is a small cylindrical aluminum bar (l = 500 mm , d = 181.7 mm ) placed at the DAΦNE Beam Test Facility, where it is hit by a 510 MeV electron beam, coming from the DAΦNE Linac. Aim of the experiment is to measure the mechanical vibrations of the bar caused by the interaction with the beam. On June, 2004 RAP successfully collected data for the first time at cryogenic temperature. Several runs at different temperatures (4.5, 70 and 273 K) have been performed and a number of shots in normal-conducting state of the bar were detected. The preliminary results are in good agreement with the Thermo-Acoustic Model. In the next months the mounting of a dilution refrigerator and the data taking of the bar in the superconducting state (T = 100 mK ) have been planned.

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