scholarly journals Spectrum of the Anomalous Microwave Emission in the North Celestial Pole withWMAP7-Year Data

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Anna Bonaldi ◽  
Sara Ricciardi
Keyword(s):  
Accurate Determination ◽  
Peak Frequency ◽  
Microwave Emission ◽  
Neutral Medium ◽  
Gas Temperature ◽  
The North ◽  
Celestial Pole ◽  
Hydrogen Ionization ◽  
Component Separation Method

We estimate the frequency spectrum of the diffuse anomalous microwave emission (AME) on the North Celestial Pole (NCP) region of the sky with the Correlated Component Analysis (CCA) component separation method applied toWMAP7-yr data. The NCP is a suitable region for this analysis because the AME is weakly contaminated by synchrotron and free-free emission. By modeling the AME component as a peaked spectrum we estimate the peak frequency to be21.7±0.8 GHz, in agreement with previous analyses which favoredνp< 23 GHz. The ability of our method to correctly recover the position of the peak is verified through simulations. We compare the estimated AME spectrum with theoretical spinning dust models to constrain the hydrogen densitynH. The best results are obtained with densities around 0.2–0.3 cm−3, typical of warm ionised medium (WIM) to warm neutral medium (WNM) conditions. The degeneracy with the gas temperature prevents an accurate determination ofnH, especially for low hydrogen ionization fractions, where densities of a few cm−3are also allowed.

Loran-C Chains: Determination of Extent of Cover

1988 ◽  
Vol 41 (02) ◽  
pp. 149-173 ◽  
Author(s):  
K. F. Woodman ◽  
J. Juleff ◽  
R. A. Allen
Keyword(s):  
Field Strength ◽  
North Sea ◽  
Western Europe ◽  
Accurate Determination ◽  
Propagation Path ◽  
North West ◽  
The North ◽  
The North Sea ◽  
Geometric Effects

A mainly theoretical study has been undertaken to demonstrate how the extent of cover from a hyperbolic navigation system chain can be evaluated. The impetus for the study was the need to assess how Loran-C could be extended over Western Europe, particularly in the South western Approaches, North Sea, English Channel and Bay of Biscay sea areas.The technique described in this article leads to an accurate determination of the electric field strength at a distance from each transmitting site and takes into account the complexities of the ground-wave propagation path. This field-strength contour is combined with the geometric effects of station siting (expansion factors) to yield a constant S/N contour (–10 dB) which defines the ¼n.m. error and hence the limit of cover for the hyperbolic chain under study.In order to exercise the analytical methods a hypothetical Loran-C chain was studied comprising a master station at Lessay (France), with secondary stations at Soustons (also in France), at Sylt (dual rated; off the North Sea coast of Germany, near the Danish border) and at a fourth station located in north-west Britain on the Hebridean island of Barra. The study indicated that such a hypothetical chain would significantly improve Loran-C cover over much of western Europe.

THE SUPPRESSION OF VITRINITE REFLECTANCE IN SOME NORTH WEST SHELF WELLS: BARROW-1, JUPITER-1 AND FLAMINGO-1

1992 ◽  
Vol 32 (1) ◽  
pp. 300 ◽  
Author(s):  
R.W.T. Wilkins ◽  
J.R. Wilmshurst ◽  
G. Hladky ◽  
M.V. Ellacott ◽  
C.P. Buckingham
Keyword(s):  
Organic Matter ◽  
Vitrinite Reflectance ◽  
Accurate Determination ◽  
Petroleum Exploration ◽  
Thermal Maturity ◽  
North West ◽  
The North ◽  
The Individual ◽  
Reflectance Data

The sediments of the North West Shelf pose several problems for the accurate determination of thermal maturity by vitrinite reflectance. There are some serious discrepancies between the results of different workers; in some wells there is a surprisingly small increase of reflectance with depth, and it is sometimes difficult to honour these data in thermal maturity modelling. There appear to be two major sources of error in the reflectance data. These are firstly, the effect known as 'suppression' of vitrinite reflectance, and secondly, the difficulty of identifying the vitrinite population in dispersed organic matter.These problems may be addressed by the fluorescence alteration technique which is closely related to vitrinite reflectance but has two special advantages. Firstly, it depends on an analysis of the fluorescence alteration response of a small representative population of organic matter in which the individual macerals need not be identified. Secondly, anomalous vitrinites with suppressed vitrinite reflectance are readily characterized, and the corrected equivalent reflectances determined.The technique has been tested on three North West Shelf petroleum exploration wells, Barrow-1, Jupiter-1 and Flamingo-1. Major discrepancies between measured and equivalent vitrinite reflectance appear to originate in part from the difficulty of identifying the vitrinite population in dispersed organic matter from marine sediments. There is also evidence of suppression of vitrinite reflectance in most samples from Barrow-1, in the Flamingo Group and Plover Formation of Flamingo-1, and in the upper part of the Mungaroo Formation of Jupiter-1.A model is proposed to facilitate the assessment of measured vitrinite reflectance data from Carnarvon or Bonaparte Basin wells. Suppression effects are likely to have influenced measured vitrinite reflectance results from wells for which the strongest data are obtained from the Lower Cretaceous fluvio-deltaic Barrow Group sediments or their equivalents.

scholarly journals XV. On the errors in longitude as determined by chronometers at sea, arising from the action of the iron in the ships upon the chronometers

1820 ◽  
Vol 110 ◽  
pp. 196-208 ◽  
Keyword(s):  
Accurate Determination ◽  
North Pole ◽  
Foreign Service ◽  
The North

The determination of the longitude at sea by timekeepers, is so exceedingly easy from the simplicity of the observations and calculations employed, and from the general practica­bility of the method, as to render chronometers, in the present improved state of navigation, almost indispensable articles in the equipment of ships for foreign service ; and I shall feel happy if the following observations may, in any way, con­tribute to the more accurate determination of the longitude by this method. The sudden alteration in the rates of chronometers when taken on board of ships, has been frequently observed by intelligent seamen ; and is generally ascribed to the motion of the vessels. Before, however, I attempt to account for this alteration, I shall first prove that it actually takes place ; and, in order to do this, shall relate the circumstances con­nected with the chronometers on board the Dorothea and Trent, commanded by Captain Buchan, which occurred du­ring the late voyage to the North Pole.

scholarly journals The C-Band All-Sky Survey (C-BASS): constraining diffuse Galactic radio emission in the North Celestial Pole region

2019 ◽  
Vol 485 (2) ◽  
pp. 2844-2860 ◽  
Author(s):  
C Dickinson ◽  
A Barr ◽  
H C Chiang ◽  
C Copley ◽  
R D P Grumitt ◽  
...  
Keyword(s):  
Dust Emission ◽  
High Sensitivity ◽  
Far Infrared ◽  
Microwave Emission ◽  
Correlation Technique ◽  
The North ◽  
Sky Survey ◽  
Celestial Pole ◽  
Source Confusion ◽  
5 Ghz

ABSTRACT The C-Band All-Sky Survey (C-BASS) is a high sensitivity all-sky radio survey at an angular resolution of 45 arcmin and a frequency of 4.7 GHz. We present a total intensity map of the North Celestial Pole (NCP) region of sky, above declination &gt;+80°, which is limited by source confusion at a level of ≈0.6 mK rms. We apply the template-fitting (cross-correlation) technique to WMAP and Planck data, using the C-BASS map as the synchrotron template, to investigate the contribution of diffuse foreground emission at frequencies ∼20–40 GHz. We quantify the anomalous microwave emission (AME) that is correlated with far-infrared dust emission. The AME amplitude does not change significantly (${\lt }10\, {{\ \rm per\ cent}}$) when using the higher frequency C-BASS 4.7 GHz template instead of the traditional Haslam 408 MHz map as a tracer of synchrotron radiation. We measure template coefficients of 9.93 ± 0.35 and $9.52\pm 0.34\,$ K per unit τ353 when using the Haslam and C-BASS synchrotron templates, respectively. The AME contributes $55\pm 2\, \mu$K rms at 22.8 GHz and accounts for ${\approx } 60{{\ \rm per\ cent}}$ of the total foreground emission. Our results show that a harder (flatter spectrum) component of synchrotron emission is not dominant at frequencies ≳5 GHz; the best-fitting synchrotron temperature spectral index is β = −2.91 ± 0.04 from 4.7 to 22.8 GHz and β = −2.85 ± 0.14 from 22.8 to 44.1 GHz. Free–free emission is weak, contributing ${\approx } 7\, \mu$K rms (${\approx } 7{{\ \rm per\ cent}}$) at 22.8 GHz. The best explanation for the AME is still electric dipole emission from small spinning dust grains.

Development of a mobile, open-circuit indirect calorimetry system

1994 ◽  
Vol 74 (1) ◽  
pp. 65-71 ◽  
Author(s):  
J. M. Kelly ◽  
B. Kerrigan ◽  
L. P. Milligan ◽  
B. W. McBride
Keyword(s):  
Oxygen Consumption ◽  
Energy Metabolism ◽  
Indirect Calorimetry ◽  
Rapid Determination ◽  
Accurate Determination ◽  
Standard Test ◽  
Open Circuit ◽  
Absolute Pressure ◽  
Gas Temperature

A system for the rapid determination of O2 consumption, CO2 production and subsequent indirect estimation of energy metabolism of ruminants has been updated and validated. The accurate determination of gas temperature, relative humidity, absolute pressure and flow is important to the overall use of the system. Analogue outputs from the specific analyzers were multiplexed and then routed to a data acquisition system with appropriate software control. Subsequent data processing included modification to fit LOTUS 1-2-3 files. The analyzers were calibrated with standard test gases for the gas meters. In an experimental confirmation trial, eight sheep were fed at maintenance (M) or 2× maintenance (2M) or fasted 48 h after each level of intake (MF and 2MF, respectively) and subsequent energy metabolism was determined. Oxygen consumption (mL min−1), metabolic rate (W) and CO2 production (mL min−1) were greater (P < 0.05) for animals fed 2M (111.2, 379.5 and 101.9, respectively) than for those fed M (85.4, 291.2 and 86.1, respectively). Maintenance values were, in turn, also higher (P < 0.05) than those for either MF (56.7, 193.4 and 48.0, respectively) or 2MF (54.6, 186.4 and 46.3, respectively). M sheep had a higher respiratory quotient (1.03) (P < 0.05) than either MF sheep (0.86) or 2MF sheep (0.89), with 2M sheep being intermediate (0.95). There were no differences (P > 0.05) between the two fasted states for all parameters. Results from the confirmation experiment agree with previously published work and were consistent with those from similar systems. Key words: Indirect calorimetry, oxygen consumption, sheep

scholarly journals Determination of tectonic velocities of some continuously operating reference stations (CORS) in Vietnam 2016-2018 by using precise point positioning

2020 ◽  
Vol 43 (1) ◽  
pp. 1-12
Author(s):  
Nguyen Ngoc Lau ◽  
Richard Coleman ◽  
Ha Minh Hoa
Keyword(s):  
Precise Point Positioning ◽  
Accurate Determination ◽  
Three Dimensional ◽  
Plate Motion ◽  
Tectonic Plate ◽  
North East ◽  
The North ◽  
Positioning Technique ◽  
Point Positioning

Determining the speed of tectonic plate displacement helps us to better understand tectonic activities of the area, and is a prerequisite to help forecast earthquakes. The determination of tectonic plate displacement by GNSS technology in Vietnam has been conducted since the 2000s, mainly using the relative positioning technique. The increasing accuracy of precise point positioning technique, and the number of CORS in Vietnam, will facilitate the accurate determination of tectonic velocities. Based on the GNSS data of some CORSs in Vietnam from 2016-2018, we have determined accurately their three-dimensional coordinates using a precise point positioning technique. After modeling periodic variations on the time series, we calculated the tectonic movement rate of 7 Vietnamese stations and 3 other stations in the region. Through analysis and comparison with other geology/plate motion models and GPS results, we conclude that this result is reliable. The velocity of tectonic motion in the North, East and Up components of Ha Noi, Da Nang and Ho Chi Minh City are respectively (-13.1, +32.8, -1.3), (-9.9, +31.0, +2.6) and (-10.3, +26.9, +2.7)  mm/year.

The Albian (Vraconnian)-Cenomanian boundary at the western Tethyan margins (Central Tunisia and southeastern France)

2008 ◽  
Vol 179 (3) ◽  
pp. 245-266 ◽  
Author(s):  
Francis Robaszynski ◽  
Francis Amédro ◽  
Jose Maria González-Donoso ◽  
Dolores Linares
Keyword(s):  
Planktonic Foraminifera ◽  
Accurate Determination ◽  
Northern Africa ◽  
Northern California ◽  
Calcareous Nannofossils ◽  
Central Tunisia ◽  
The North ◽  
North And South ◽  
Se France

AbstractThrough the description and interpretation of the position of macro- and microfossils in several sections of the Albian-Cenomanian boundary in SE France and Central Tunisia, a comparison is made between the north and south margins of the Tethyan Ocean by using the occurrences of marker bioevents. For the planktonic foraminifera, the criterions applicable for the accurate determination of Thalmanninella globotruncanoides (Sigal) – the marker species for the base of the Cenomanian stage – are discussed. The species Th. globotruncanoides and the intermediate forms with its ancestor Th. caroni (Ion) are illustrated. For the ammonites, two subjects are new. Firstly, the species Stoliczkaia (Shumarinaia) africana Pervinquiere is illustrated since it is choosen as the indice of the uppermost zone of the Albian (Vraconnian). In northern Africa it replaces Arrhaphoceras (Praeschloenbachia) briacensis (Scholz), the indice for northern Tethys, but restricted to the North European Province. Secondly, specimens of the two genera Graysonites and Utaturiceras – first found in the basal Cenomanian of northern Africa – are described and illustrated.To allow a comparison between north and south Mediterranean sections, respectively Mont Risou and Marcoule for the north and Tunisia for the south, the stratigraphical position of several proxies from planktonic foraminifera, calcareous nannofossils and ammonites are discussed. A widening of the comparison is proposed by taking into account distant regions such as Madagascar and northern California.

scholarly journals A model of gas flow with friction in a slotted seal

2016 ◽  
Vol 37 (3) ◽  
pp. 95-108 ◽  
Author(s):  
Damian Joachimiak ◽  
Piotr Krzyślak
Keyword(s):  
Friction Coefficient ◽  
Mass Flow ◽  
Gas Flow ◽  
Pressure Ratio ◽  
Accurate Determination ◽  
Gas Temperature ◽  
Total Enthalpy ◽  
Proposed Model ◽  
Adiabatic Transformation

AbstractThe paper discusses thermodynamic phenomena accompanying the flow of gas in a slotted seal. The analysis of the gas flow has been described based on an irreversible adiabatic transformation. A model based on the equation of total enthalpy balance has been proposed. The iterative process of the model aims at obtaining such a gas temperature distribution that will fulfill the continuity equation. The model allows for dissipation of the kinetic energy into friction heat by making use of the Blasius equation to determine the friction coefficient. Within the works, experimental research has been performed of the gas flow in a slotted seal of slot height 2 mm. Based on the experimental data, the equation of local friction coefficient was modified with a correction parameter. This parameter was described with the function of pressure ratio to obtain a mass flow of the value from the experiment. The reason for taking up of this problem is the absence of high accuracy models for calculating the gas flow in slotted seals. The proposed model allows an accurate determination of the mass flow in a slotted seal based on the geometry and gas initial and final parameters.

A quantitative approach to inner shell losses

1978 ◽  
Vol 36 (1) ◽  
pp. 526-527 ◽  
Author(s):  
R.D. Leapman ◽  
P. Rez ◽  
D.F. Mayers
Keyword(s):  
Energy Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Accurate Determination ◽  
Background Intensity ◽  
Core Excitation ◽  
Quantitative Basis ◽  
Cross Section Differential ◽  
Bound Electrons

Microanalysis by EELS has been developing rapidly and though the general form of the spectrum is now understood there is a need to put the technique on a more quantitative basis (1,2). Certain aspects important for microanalysis include: (i) accurate determination of the partial cross sections, σx(α,ΔE) for core excitation when scattering lies inside collection angle a and energy range ΔE above the edge, (ii) behavior of the background intensity due to excitation of less strongly bound electrons, necessary for extrapolation beneath the signal of interest, (iii) departures from the simple hydrogenic K-edge seen in L and M losses, effecting σx and complicating microanalysis. Such problems might be approached empirically but here we describe how computation can elucidate the spectrum shape.The inelastic cross section differential with respect to energy transfer E and momentum transfer q for electrons of energy E0 and velocity v can be written as

Fast calibration of CBED patterns for quantitative analysis

1993 ◽  
Vol 51 ◽  
pp. 674-675
Author(s):  
M.A. Gribelyuk ◽  
M. Rühle
Keyword(s):  
Reciprocal Lattice ◽  
Accurate Determination ◽  
Incident Beam ◽  
Crystal Thickness ◽  
Structure Model ◽  
Beam Direction ◽  
Transmitted Beam ◽  
Reciprocal Vector ◽  
On Line

A new method is suggested for the accurate determination of the incident beam direction K, crystal thickness t and the coordinates of the basic reciprocal lattice vectors V1 and V2 (Fig. 1) of the ZOLZ plans in pixels of the digitized 2-D CBED pattern. For a given structure model and some estimated values Vest and Kest of some point O in the CBED pattern a set of line scans AkBk is chosen so that all the scans are located within CBED disks.The points on line scans AkBk are conjugate to those on A0B0 since they are shifted by the reciprocal vector gk with respect to each other. As many conjugate scans are considered as CBED disks fall into the energy filtered region of the experimental pattern. Electron intensities of the transmitted beam I0 and diffracted beams Igk for all points on conjugate scans are found as a function of crystal thickness t on the basis of the full dynamical calculation.

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