Computer assisted performance tests of the Lyman Alpha Coronagraph

Preflight calibration and performance tests of the Lyman Alpha Coronagraph rocket instrument in the laboratory, with the experiment in its flight configuration and illumination levels near those expected during flight were successfully carried out using a pulse code modulation telemetry system simulator interfaced in real time to a PDP 11/10 computer system. Post acquisition data reduction programs developed and implemented on the same computer system aided in the interpretation of test and calibration data

Lyman alpha coronagraph research sounding rocket program

The ultraviolet light coronagraph was developed and successfully flown on three rocket flights on 13 April 1979, 16 February 1980 and 20 July 1982. During each of these flights, the Ultraviolet Light Coronagraph was flown jointly with the White Light Coronagraph provided by the High Altitude Observatory. Ultraviolet diagnostic techniques and instrumentation for determining the basic plasma parameters of solar wind acceleration regions in the extended corona were developed and verified and the understanding of the physics of the corona through the performance, analysis and interpretation of solar observations advanced. Valuable UV diagnostics can be performed in the absence of a natural solar eclipse

China’s Artificial Island Building Campaign in the South China Sea: Implications for the Reform of the United Nations Convention on the Law of the Sea

This Comment discusses the United Nations Convention on the Law of the Sea (UNCLOS) with reference to artificial island building in the South China Sea. China recently began an artificial island building campaign in the Spratly Island chain, which is located in the South China Sea. These artificial islands have been the subject of, and have created implications regarding, territorial disputes in the area. UNCLOS governs international law in the context of disputes among states on the high seas. UNCLOS does have provisions that address artificial island construction and maintenance, but it mistakenly assumes that states will only construct artificial islands within their own exclusive economic zone (EEZ). An international arbitral tribunal established by UNCLOS determined that a state may not build an artificial island within the exclusive economic zone of another state. In this way, the tribunal interpreted UNCLOS to have a prohibitory rather than permissive effect when it comes to artificial island construction. The tribunal’s determination in that case may have legally resolved that territorial dispute, but it does not provide clear guidance for determining the legitimacy of a state constructing an artificial island in international waters not within its own EEZ or an EEZ belonging to another state. This open question is important because several of China’s artificial islands in the South China Sea fall into that category. This Comment recommends that UNCLOS be amended by the state parties to clarify the law of the sea with reference to artificial islands. Specifically, states should only be allowed to build artificial islands at a location that is within its own EEZ and is not located within another state’s EEZ

Reactions of NaCl with Gaseous SO3, SO2, and O2

Hot corrosion of gas turbine engine components involves deposits of Na2SO4 which are produced by reactions between NaCl and oxides of sulfur. For the present investigation, NaCl single crystals were exposed at 100 to 850 C to gaseous mixtures of SO3, SO2, and O2. The products formed during this exposure depend, primarily, on the temperatures. The four product films were: NaCl-SO3; Na2S2O7; Na2SO4; and NaCl-Na2SO4. The kinetics of the reactions were measured

Rocket spectrometer for investigation of the far ultraviolet solar spectrum

A rocket-borne Ebert spectrometer and telescope were used for analysis of the solar spectrum. The instrument was arranged in the high resolution line scanning mode. Selected emission lines between 1170 and 1640 A were scanned, and a complete wavelength scan was made from 1170 A to 1850 A. Accurate measurements were made of the line profiles of the He II lines at 1640 A, C IV lines at 1550 A, Si IV lines at 1400 A, C II lines at 1335 A, the N V lines at 1240 A, and the C III lines at 1175 A. Accurate intensity measurements of the quiet sun spectrum for wavelengths between 1174 A and 3220 A were obtained. Spectral resolution was better than 0.03 A over most of the range and spatial resolution was relatively low so that the observations are averaged over the chromospheric network. Plots of absolute intensity versus wave length were prepared for the full wavelength range of the observations

The Easement in Gross Revisited: Transferability and Divisibility Since 1945

Courts have disagreed about the nature, obligations, and privileges that accompany the easement in gross. Generally, an easement is an interest in land which gives the easement holder the right to use that land for a specific purpose, free from the will of the landowner. An easement is in gross when the benefit from the use of another\u27s land inures to the easement holder personally, rather than to the holder\u27s land. The land that is subject to the holder\u27s right of use is the servient tenement. Courts agree on these basic principles of an easement in gross, but have disagreed on the holder\u27s right to transfer his interest to a third party. Similarly, no uniformity exists among courts on the right of the holder of an easement in gross to divide and share his interest with a third party. In the mid-1940\u27s, two commentators compiled and analyzed the state of the law concerning the transferability and divisibility of easements in gross. Both writers attested to the importance of easements in gross in facilitating commercial activity, especially in the area of transportation rights of way and public utilities. Each author noted that the common law rule disfavored transferability and divisibility of easements in gross because the rights accompanying the easement were personal to the holder. The two writers noted, however, that the common law rule was beginning to changeand that courts were allowing limited transfers and divisions of easements in gross.\u27 Emphasizing that a party could not realize the maximum value of an easement in gross unless the courts allowed the easement holder to transfer or divide his interest, both men concluded their essays with a call for a greater consensus among the courts and for fewer restrictions on the transferability and divisibility of easements in gross. These commentaries appeared over forty years ago. Today,easements in gross continue to play an important commercial role and are finding new uses in fields such as environmental conservation and historic preservation.\u27 Despite the growing importance of easements in gross, commentators during this forty-year span have neglected to address the questions of transferability and divisibility. The purpose of this Note is to gather and analyze the law of transferability and divisibility of easements in gross as the law has developed since 1945. Part II of this Note differentiates easements in gross from other types of real servitudes. Part III discusses the variety of approaches that courts and legislatures have taken in addressing the question of transferability. Part IV deals with the development of the independent exercise doctrine of divisibility.Last, part V advocates that courts should place less emphasis on terminology and should direct more attention toward the parties\u27intentions and the surrounding circumstances of the easement interest when determining the transferability and divisibility of easements in gross

Absolute flux measurements for swift atoms

While a torsion balance in vacuum can easily measure the momentum transfer from a gas beam impinging on a surface attached to the balance, this measurement depends on the accommodation coefficients of the atoms with the surface and the distribution of the recoil. A torsion balance is described for making absolute flux measurements independent of recoil effects. The torsion balance is a conventional taut suspension wire design and the Young modulus of the wire determines the relationship between the displacement and the applied torque. A compensating magnetic field is applied to maintain zero displacement and provide critical damping. The unique feature is to couple the impinging gas beam to the torsion balance via a Wood's horn, i.e., a thin wall tube with a gradual 90 deg bend. Just as light is trapped in a Wood's horn by specular reflection from the curved surfaces, the gas beam diffuses through the tube. Instead of trapping the beam, the end of the tube is open so that the atoms exit the tube at 90 deg to their original direction. Therefore, all of the forward momentum of the gas beam is transferred to the torsion balance independent of the angle of reflection from the surfaces inside the tube

A Model for the Stray Light Contamination of the UVCS Instrument on SOHO

We present a detailed model of stray-light suppression in the spectrometer channels of the Ultraviolet Coronagraph Spectrometer (UVCS) on the SOHO spacecraft. The control of diffracted and scattered stray light from the bright solar disk is one of the most important tasks of a coronagraph. We compute the fractions of light that diffract past the UVCS external occulter and non-specularly pass into the spectrometer slit. The diffracted component of the stray light depends on the finite aperture of the primary mirror and on its figure. The amount of non-specular scattering depends mainly on the micro-roughness of the mirror. For reasonable choices of these quantities, the modeled stray-light fraction agrees well with measurements of stray light made both in the laboratory and during the UVCS mission. The models were constructed for the bright H I Lyman alpha emission line, but they are applicable to other spectral lines as well.Comment: 19 pages, 5 figures, Solar Physics, in pres

Laboratory studies in ultraviolet solar physics

The research activity comprised the measurement of basic atomic processes and parameters which relate directly to the interpretation of solar ultraviolet observations and to the development of comprehensive models of the component structures of the solar atmosphere. The research was specifically directed towards providing the relevant atomic data needed to perform and to improve solar diagnostic techniques which probe active and quiet portions of the solar chromosphere, the transition zone, the inner corona, and the solar wind acceleration regions of the extended corona. The accuracy with which the physical conditions in these structures can be determined depends directly on the accuracy and completeness of the atomic and molecular data. These laboratory data are used to support the analysis programs of past and current solar observations (e.g., the Orbiting solar Observatories, the Solar Maximum Mission, the Skylab Apollo Telescope Mount, and the Naval Research Laboratory's rocket-borne High Resolution Telescope and Spectrograph). In addition, we attempted to anticipate the needs of future space-borne solar studies such as from the joint ESA/NASA Solar and Heliospheric Observatory (SOHO) spacecraft. Our laboratory activities stressed two categories of study: (1) the measurement of absolute rate coefficients for dielectronic recombination and electron impact excitation; and (2) the measurement of atomic transition probabilities for solar density diagnostics. A brief summary of the research activity is provided