Alien Registration- Bell, William G. (Portland, Cumberland County)

https://digitalmaine.com/alien_docs/24202/thumbnail.jp

Alien Registration- Bell, William G. (Portland, Cumberland County)

https://digitalmaine.com/alien_docs/24202/thumbnail.jp

Hydrothermal activity lowers trophic diversity in Antarctic sedimented hydrothermal vents

Sedimented hydrothermal vents are those in which hydrothermal fluid vents through sediment and are among the least studied deep-sea ecosystems. We present a combination of microbial and biochemical data to assess trophodynamics between and within hydrothermally active and off-vent areas of the Bransfield Strait (1050–1647 m depth). Microbial composition, biomass and fatty acid signatures varied widely between and within vent and non-vent sites and provided evidence of diverse metabolic activity. Several species showed diverse feeding strategies and occupied different trophic positions in vent and non-vent areas and stable isotope values of consumers were generally not consistent with feeding structure morphology. Niche area and the diversity of microbial fatty acids reflected trends in species diversity and was lowest at the most hydrothermally active site. Faunal utilisation of chemosynthetic activity was relatively limited but was detected at both vent and non-vent sites as evidenced by carbon and sulphur isotopic signatures, suggesting that the hydrothermal activity can affect trophodynamics over a much wider area than previously thought

Surface Electromagnetic Waves with Damping. I. Isotropic Media

Surface-Electromagnetic-Wave Dispersion Curves Are Usually Calculated using a Simple Equation Derived from Maxwell\u27s Equations and Boundary Conditions. When Complex Dielectric Functions Are Used for the Two Media, the Component of the Propagation Vector Along the Surface, Kx, Becomes Infinite as the Frequency Approaches the Surface Polariton Frequency Ωs If Ω is Considered Complex and Kx is Real. on the Other Hand, If Kx is Considered Complex and Ω Real, the Dispersion Curves Bend Back Toward Smaller Kx as Ω Approaches Ωs. We Have Previously Demonstrated that Both Types of Behavior Can Be Obtained from Attenuated-Total-Reflection Measurements of Silver. We Now Extend This Result to Other Materials and Show that Dispersion Curves Alone Present an Inadequate Summary of the Data. © 1976 the American Physical Society

Dispersion Curves for Surface Electromagnetic Waves with Damping

The Recent Observation of Back bending in the Dispersion Curves of Surface Plasmons on Silver Can Be Explained by Use of Fresnel\u27s Equations. in the Presence of Damping, the Results of Attenuated-Total-Reflection Measurements Can Be Displayed as Dispersion Curves Either with or Without Back bending. the Measurements for Silver with Back Bending Are Expected for Experiments in Which the Frequency is Fixed, and the Propagation Constant (Or Angle of Incidence) is Swept. © 1974 the American Physical Society

Deployment Technology of a Heliogyro Solar Sail for Long Duration Propulsion

Interplanetary, multi-mission, station-keeping capabilities will require that a spacecraft employ a highly efficient propulsion-navigation system. The majority of space propulsion systems are fuel-based and require the vehicle to carry and consume fuel as part of the mission. Once the fuel is consumed, the mission is set, thereby limiting the potential capability. Alternatively, a method that derives its acceleration and direction from solar photon pressure using a solar sail would eliminate the requirement of onboard fuel to meet mission objectives. MacNeal theorized that the heliogyro-configured solar sail architecture would be lighter, less complex, cheaper, and less risky to deploy a large sail area versus a masted sail. As sail size increases, the masted sail requires longer booms resulting in increased mass, and chaotic uncontrollable deployment. With a heliogyro, the sail membrane is stowed as a roll of thin film forming a blade when deployed that can extend up to kilometers. Thus, a benefit of using a heliogyro-configured solar sail propulsion technology is the mission scalability as compared to masted versions, which are size constrained. Studies have shown that interplanetary travel is achievable by the heliogyro solar sail concept. Heliogyro solar sail concept also enables multi-mission missions such as sample returns, and supply transportation from Earth to Mars as well as station-keeping missions to provide enhanced warning of solar storm. This paper describes deployment technology being developed at NASA Langley Research Center to deploy and control the center-of-mass/center-of-pressure using a twin bladed heliogyro solar sail 6-unit (6U) CubeSat. The 6U comprises 2x2U blade deployers and 2U for payload. The 2U blade deployers can be mounted to 6U or larger scaled systems to serve as a non-chemical in-space propulsion system. A single solar sail blade length is estimated to be 2.4 km with a total area from two blades of 720 m2; total allowable weight of a 6U CubeSat is approximately 8 kg. This makes the theoretical characteristic acceleration of approximately 0.75 mm/s2 at I AU (astronomical unit), when compared to IKAROS (0.005 mm/s2) and NanoSail-D (0.02 mm/s2)

Intrinsically narrowband pair photon generation in microstructured fibres

In this paper we study the tailoring of photon spectral properties generated by four-wave mixing in a birefringent photonic crystal fibre (PCF). The aim is to produce intrinsically narrow-band photons and hence to achieve high non-classical interference visibility and generate high fidelity entanglement without any requirement for spectral filtering, leading to high effective detection efficiencies. We show unfiltered Hong-Ou-Mandel interference visibilities of 77% between photons from the same PCF, and 80% between separate sources. We compare results from modelling the PCF to these experiments and analyse photon purities.Comment: 23 pages, 17 figures, Comments Welcom

Surface Electromagnetic Waves with Damping. II. Anisotropic Media

The Technique of Plotting the Attenuated-Total-Reflection (ATR) Reflectance as a Function of Both Frequency and Incident Angle using a Three-Dimensional Plot is Applied to Surface Electromagnetic Waves (SEW) in a Uniaxial Material, MnF2. It is Shown that Dispersion Curves Calculated Without Absorption Do Not Completely Describe the ATR Reflectivity. Experimental Data Confirming the Reflectance Surface Features Are Presented. Also, Additional Minima in the Reflectance Surface Not Associated with SEW Are Discussed. © 1977 the American Physical Society