Sulfur-oxygen processes on Io

Laboratory studies of irradiated sulfur dioxide frost have found that sulfur trioxide should be formed as a consequence of the irradiation process. The spectral reflectance of solid sulfur trioxide was measured in the laboratory and it was found that the compound has strong absorption features at 3.37 and 3.70 microns. These features are not present in the spectral geometric albedo of Io. This is interpreted as an indication that sulfur trioxide may exist in such limited abundance that it is undetectable in disk averaged spectrophotometry. It is suggested that the Near-Infrared Mapping Spectrometer on the Galileo spacecraft should be able to identify condensed sulfur trioxide on Io particularly in regions bordering the sulfur dioxide deposits. The presence of elemental sulfur on Io's surface has been questioned on several grounds, most notably the suggested production process (quenched molten sulfur extrusions) and the effect of radiation (particularly X-rays) on some of the allotropes. Mixtures of sulfur allotropes were produced in the laboratory by quenching molten sulfur and it was found that the spectra indicate the presence of certain red-colored allotropes which are preserved upon quenching. The color of the sulfur glass produced is redder when the temperature of the original melt is higher. This is consistent with the suggestion that Io's spectral geometric albedo can be partly explained by the presence of quenched sulfur glasses

Social-Network Theory and the Diffusion of the Search-and-Seizure Exclusionary Rule Among State Courts Between Weeks and Wolf

In light of the Supreme Court’s recent narrowing of the Fourth Amendment exclusionary rule in cases like Herring v. United States and Davis v. United States, there is renewed interest in whether state supreme courts will maintain or similarly narrow the search and seizure exclusionary rule for violations of their own state constitutions. The pattern of early adoptions of the exclusionary rule as a matter of state law before it was mandated by the federal Constitution may provide interesting insights into how the state supreme courts will respond to cases such as Herring and Davis. This article uses social-network theory to evaluate the patterns of communication and influence across state courts in the diffusion of the search and seizure exclusionary rule as a matter of state constitutional law. During the period studied, the Supreme Court made the exclusionary rule mandatory in federal criminal prosecutions for violations of the Fourth Amendment, but had not yet ruled that the Fourth Amendment applied to the states. We conceptualize the diffusion of the exclusionary rule in state courts as a matter of state law as a two-stage process. The first stage concerns whether the issue of exclusion of evidence obtained through illegal searches and seizures in violation of state constitutional law was presented to state supreme courts following adoption of the federal exclusionary rule in Weeks v. United States. The second stage concerns whether the state courts adopted the exclusionary rule as a matter of state law, before Wolf v. Colorado, when the Fourth Amendment was made applicable to the states. This article uses logistic regressions to evaluate the pattern of communication and influence among state courts in the diffusion of the exclusionary rule at each stage in the process. The results are striking. They suggest that precedents by other state supreme courts in the same West legal reporting regions were more influential in determining whether the question would arise in a particular state than precedents by state supreme courts in neighboring states, or the same federal circuit regions, or the same census regions. But precedents by other state supreme courts in the same federal circuit regions appear to have been more influential in determining whether the exclusionary rule would be adopted than precedents in neighboring states, the same West reporting regions, or the same census regions. These results both corroborate and extend those of previous studies

The Cause of the Hot Spot in Vegetation Canopies and Soils: Shadow-Hiding Versus Coherent Backscatter

Two different mechanisms, shadow-hiding and coherent backscatter, can cause a hot spot, or opposition effect, in the bidirectional reflectance of vegetation and soils. Because the two mechanisms sample different properties, it is important to know which one is primarily responsible in a given medium. This question can be answered by measuring the bidirectional reflectance in circularly polarized light. If the results of the limited experiments reported here can be extrapolated to a wider range of materials, it appears that the primary cause of the hot spot in most vegetation canopies and in moist, clumpy soils is shadow-hiding. However, in vegetation with large numbers of wavelength-sized structures, such as mosses, and in dry, fine-grained soils, the hot spot is dominated by coherent backscatter

Social-Network Theory and the Diffusion of the Search-and-Seizure Exclusionary Rule Among State Courts Between Weeks and Wolf

In light of the Supreme Court’s recent narrowing of the Fourth Amendment exclusionary rule in cases like Herring v. United States and Davis v. United States, there is renewed interest in whether state supreme courts will maintain or similarly narrow the search and seizure exclusionary rule for violations of their own state constitutions. The pattern of early adoptions of the exclusionary rule as a matter of state law before it was mandated by the federal Constitution may provide interesting insights into how the state supreme courts will respond to cases such as Herring and Davis. This article uses social-network theory to evaluate the patterns of communication and influence across state courts in the diffusion of the search and seizure exclusionary rule as a matter of state constitutional law. During the period studied, the Supreme Court made the exclusionary rule mandatory in federal criminal prosecutions for violations of the Fourth Amendment, but had not yet ruled that the Fourth Amendment applied to the states. We conceptualize the diffusion of the exclusionary rule in state courts as a matter of state law as a two-stage process. The first stage concerns whether the issue of exclusion of evidence obtained through illegal searches and seizures in violation of state constitutional law was presented to state supreme courts following adoption of the federal exclusionary rule in Weeks v. United States. The second stage concerns whether the state courts adopted the exclusionary rule as a matter of state law, before Wolf v. Colorado, when the Fourth Amendment was made applicable to the states. This article uses logistic regressions to evaluate the pattern of communication and influence among state courts in the diffusion of the exclusionary rule at each stage in the process. The results are striking. They suggest that precedents by other state supreme courts in the same West legal reporting regions were more influential in determining whether the question would arise in a particular state than precedents by state supreme courts in neighboring states, or the same federal circuit regions, or the same census regions. But precedents by other state supreme courts in the same federal circuit regions appear to have been more influential in determining whether the exclusionary rule would be adopted than precedents in neighboring states, the same West reporting regions, or the same census regions. These results both corroborate and extend those of previous studies

Yılan sokması

Robert Smythe Hichens'ın İleri'de yayımlanan Yılan Sokması adlı romanının ilk ve son tefrikalar

Force on a neutral atom near conducting microstructures

We derive the non-retarded energy shift of a neutral atom for two different geometries. For an atom close to a cylindrical wire we find an integral representation for the energy shift, give asymptotic expressions, and interpolate numerically. For an atom close to a semi-infinite halfplane we determine the exact Green's function of the Laplace equation and use it derive the exact energy shift for an arbitrary position of the atom. These results can be used to estimate the energy shift of an atom close to etched microstructures that protrude from substrates.Comment: 7 pages, 5 figure

Additional Drive Circuitry for Piezoelectric Screw Motors

Modules of additional drive circuitry have been developed to enhance the functionality of a family of commercially available positioning motors (Picomotor . or equivalent) that provide linear motion controllable, in principle, to within increments .30 nm. A motor of this type includes a piezoelectric actuator that turns a screw. Unlike traditional piezoelectrically actuated mechanisms, a motor of this type does not rely on the piezoelectric transducer to hold position: the screw does not turn except when the drive signal is applied to the actuator

Space Mirror Alignment System

An optical alignment mirror mechanism (AMM) has been developed with angular positioning accuracy of +/-0.2 arcsec. This requires the mirror s linear positioning actuators to have positioning resolutions of +/-112 nm to enable the mirror to meet the angular tip/tilt accuracy requirement. Demonstrated capabilities are 0.1 arc-sec angular mirror positioning accuracy, which translates into linear positioning resolutions at the actuator of 50 nm. The mechanism consists of a structure with sets of cross-directional flexures that enable the mirror s tip and tilt motion, a mirror with its kinematic mount, and two linear actuators. An actuator comprises a brushless DC motor, a linear ball screw, and a piezoelectric brake that holds the mirror s position while the unit is unpowered. An interferometric linear position sensor senses the actuator s position. The AMMs were developed for an Astrometric Beam Combiner (ABC) optical bench, which is part of an interferometer development. Custom electronics were also developed to accommodate the presence of multiple AMMs within the ABC and provide a compact, all-in-one solution to power and control the AMMs