The Calculation of Astronomical Refraction in Marine Navigation

1982 ◽  
Vol 35 (2) ◽  
pp. 255-259 ◽  
Author(s):  
G. G. Bennett
Keyword(s):  
Wide Range ◽  
Temperature And Pressure ◽  
Astronomical Refraction ◽  
Marine Navigation ◽  
Nautical Almanac

Since programmable electronic calculators were first employed in marine navigation, a variety of formulae has been used for calculating astronomical refraction. As the choice is wide, some formulae have been selected from commonly used reference sources and their accuracy and suitability examined. No attempt has been made to assess the validity of the selected formulae to represent astronomical refraction in practical circumstances. Accuracy comparisons have been made using the refraction algorithm proposed by Garfinkel – the standard adopted by the British and American Nautical Almanac Offices. New formulae are given that are simple and accurate, even over a wide range of temperature and pressure, and which for all practical purposes may be considered equivalent to the tables of refraction given in the Nautical Almanac.

scholarly journals An origin of the variations of astronomical refraction

1979 ◽  
Vol 89 ◽  
pp. 27-33
Author(s):  
Haruo Yasuda ◽  
Rikinosuke Fukaya
Keyword(s):  
Surface Layer ◽  
Correction Term ◽  
Empirical Relation ◽  
Scale Height ◽  
Atmospheric Density ◽  
Analytical Expression ◽  
Temperature And Pressure ◽  
Astronomical Refraction

There exists an empirical relation between the anomalous refraction and the atmospheric density in the surface layer. From the relations the variations of scale height for each night can be determined by the temperature and pressure in the surface layer. A correction term to the refraction table is derived in an analytical expression.

Spectrophotometry of Aqueous HNO3, H2SO4, and DCIO4 from 25° to 250°C

1968 ◽  
Vol 22 (5) ◽  
pp. 545-548 ◽  
Author(s):  
W. C. Waggener ◽  
A. J. Weinberger ◽  
R. W. Stoughton
Keyword(s):  
Cell Wall ◽  
Corrosion Products ◽  
Spectral Measurements ◽  
Wide Range ◽  
General Program ◽  
Cell Window ◽  
Temperature And Pressure

Dilute nitric, sulfuric, and perchloric acids are applicable as solvents for spectrophotometry up to 250°C over the following ranges: 0 to 1.0 f HNO3 from 0.6 to 1.2 μ; 0 to 0.2 f H2SO4 from 0.25 to 1.2 μ; and 0 to 1.0 f DClO4 from 0.25 to 1.8 μ. Each of these acids reacts measurably with the titanium cell wall and the sapphire windows at rates which increase with acidity and temperature. This corrosion affects the spectral measurements as a function of time and is associated with deterioration of cell window surfaces and the presence in the sample of dissolved and suspended corrosion products. These results are part of our more general program for the development of equipment and technique for routine spectrophotometry of pure liquids and solutions over a wide range of temperature and pressure.

Thermodynamic Properties of Pure and Mixed Thermal Plasmas Over a Wide Range of Temperature and Pressure

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Omid Askari
Keyword(s):  
Thermodynamic Properties ◽  
Specific Heat ◽  
Fluid Dynamic ◽  
Thermal Plasmas ◽  
Statistical Thermodynamic ◽  
Reference Source ◽  
Degree Of Ionization ◽  
Wide Range ◽  
Self Consistent ◽  
Temperature And Pressure

Chemical composition and thermodynamics properties of different thermal plasmas are calculated in a wide range of temperatures (300–100,000 K) and pressures (10−6–100 atm). The calculation is performed in dissociation and ionization temperature ranges using statistical thermodynamic modeling. The thermodynamic properties considered in this study are enthalpy, entropy, Gibbs free energy, specific heat at constant pressure, specific heat ratio, speed of sound, mean molar mass, and degree of ionization. The calculations have been done for seven pure plasmas such as hydrogen, helium, carbon, nitrogen, oxygen, neon, and argon. In this study, the Debye–Huckel cutoff criterion in conjunction with the Griem’s self-consistent model is applied for terminating the electronic partition function series and to calculate the reduction of the ionization potential. The Rydberg and Ritz extrapolation laws have been used for energy levels which are not observed in tabulated data. Two different methods called complete chemical equilibrium and progressive methods are presented to find the composition of available species. The calculated pure plasma properties are then presented as functions of temperature and pressure, in terms of a new set of thermodynamically self-consistent correlations for efficient use in computational fluid dynamic (CFD) simulations. The results have been shown excellent agreement with literature. The results from pure plasmas as a reliable reference source in conjunction with an alternative method are then used to calculate the thermodynamic properties of any arbitrary plasma mixtures (mixed plasmas) having elemental atoms of H, He, C, N, O, Ne, and Ar in their chemical structure.

The Earth's Magnetic Field

1950 ◽  
Vol 3 (1) ◽  
pp. 1-9
Author(s):  
Harold Spencer Jones
Keyword(s):  
Magnetic Field ◽  
High Speed ◽  
Spherical Triangle ◽  
Basic Data ◽  
Earth’S Magnetic Field ◽  
Wide Range ◽  
Earth's Magnetic Field ◽  
The Many ◽  
Right Ascension ◽  
Nautical Almanac

The Institute has now completed two years of its existence. The papers which have been read before it during these two years have covered a wide range of subjects and have served to emphasize the many ramifications of the science of navigation. Because of the high speed of modern aircraft, air navigation presents more problems and of greater variety than surface navigation, but even on the problems of surface navigation there has been ample scope for a wide range of discussion. The Institute has taken a prominent part in the discussion of the proposals for the revision of the Abridged Nautical Almanac. It might with some reason have been supposed that there was nothing more to be said on the methods of reducing astro-sights and determining position at sea. The problem is perfectly straightforward and there is a limit to the number of different ways in which the spherical triangle can be solved. But the essential basic data can be presented in a variety of ways, while there are many possible methods of presenting tables for the solution of the spherical triangle. The decision to use Greenwich hour angle instead of right ascension in the Abridged Nautical Almanac has followed its adoption in the Air Almanac; the revised Almanac will have an entirely different format from the present, while the methods of reducing sights must be correspondingly modified.

Empirical Model of Operating Temperature and Pressure Effect towards Pure and Binary O2/ N2 Gas Permeability in Polysulfone Membrane

2018 ◽  
Vol 777 ◽  
pp. 238-244
Author(s):  
Serene Sow Mun Lock ◽  
Kok Keong Lau ◽  
Irene Sow Mei Lock ◽  
Azmi Mohd Shariff ◽  
Yin Fong Yeong ◽  
...  
Keyword(s):  
Empirical Model ◽  
Membrane Separation ◽  
Gas Permeability ◽  
Economic Assessment ◽  
Operating Conditions ◽  
Effect Of Temperature ◽  
Polysulfone Membrane ◽  
Wide Range ◽  
Temperature And Pressure ◽  
Membrane Permeance

Oxygen (O2) enriched air combustion via adaption of polymeric membranes has been proposed to be a feasible alternative to increase combustion proficiency while minimizing the emission of greenhouse gases into the atmosphere. Nonetheless, majority of techno-economic assessment on the O2 enriched combustion evolving membrane separation process are confined to assumption of constant membrane permeance. In reality, it is well known that membrane permeance is highly dependent upon the temperature and pressure to which it is operated. Therefore, in this work, an empirical model, which includes the effect of temperature and pressure to permeance, has been evaluated based on own experimental work using polysulfone membrane. The empirical model has been further validated with published experimental results. It is found that the model is able to provide an excellent characterization of the membrane permeance across a wide range of operating conditions for both pure and binary gas with determination coefficient of minimally 0.99.

Numerical modeling of hydration performance for well cement exposed to a wide range of temperature and pressure

2020 ◽  
Vol 261 ◽  
pp. 119929
Author(s):  
Xuerui Wang ◽  
Baojiang Sun ◽  
Songyan Li ◽  
Zhiyuan Wang ◽  
Hao Li ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Wide Range ◽  
Temperature And Pressure ◽  
Well Cement
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