65,939 research outputs found
Interface circuitry for superconducting bolometer
The interface circuitry described links the computer with the superconducting bolometer array. This helps demonstrate the feasibility of the array. Using the circuitry and the array, imaging will be made possible. Initial imaging will be done on laboratory objects, and the pixel characteristics will be investigated experimentally
Mobi algebra as an abstraction to the unit interval and its comparison to rings
We introduce a new algebraic structure, called mobi algebra, consisting of three constants and one ternary operation. The canonical example of a mobi algebra is the unit interval with the three constants 0, 1, and 1/2 and the ternary operation given by the formula x−yx+yz. We study some of its properties and prove that every unitary ring with one half uniquely determines and is uniquely determined by a mobi algebra with one double. Another algebraic structure, called involutive medial monoid (IMM), is considered to establish the passage between rings and mobi algebras.info:eu-repo/semantics/publishedVersio
Terrestrial planet formation in low eccentricity warm-Jupiter systems
We examine the effect of giant planet migration on the formation of inner
terrestrial planet systems. We consider situations in which the giant planet
halts migration at semi-major axes in the range 0.13 - 1.7 AU due to gas disk
dispersal. An N-body code is employed that is linked to a viscous gas disk
algorithm capable of simulating: gas loss via accretion onto the central star
and photoevaporation; gap formation by the giant planet; type II migration of
the giant; optional type I migration of protoplanets; gas drag on
planetesimals. We find that most of the inner system planetary building blocks
survive the passage of the giant planet, either by being shepherded inward or
scattered into exterior orbits. Systems of one or more hot-Earths are predicted
to form and remain interior to the giant planet, especially if type II
migration has been limited, or where type I migration has affected
protoplanetary dynamics. Habitable planets in low eccentricity warm-Jupiter
systems appear possible if the giant planet makes a limited incursion into the
outer regions of the habitable zone (HZ), or traverses its entire width and
ceases migrating at a radial distance of less than half that of the HZ's inner
edge. We conclude that Type II migration does not prevent terrestrial planet
formation.Comment: Accepted for publication in A&A; 18 pages, 12 figures, 2 table
On the formation of terrestrial planets in hot-Jupiter systems
We present a series of calculations aimed at examining how an inner system of
planetesimals/protoplanets, undergoing terrestrial planet formation, evolves
under the influence of a giant planet undergoing inward type II migration
through the region bounded between 5 - 0.1 AU. We find that > 60% of the solids
disk survives by being scattered by the giant planet into external orbits.
Planetesimals are scattered outward almost as efficiently as protoplanets,
resulting in the regeneration of a solids disk where dynamical friction is
strong and terrestrial planet formation is able to resume. A simulation
extended for a few Myr after the migration of the giant planet halted at 0.1
AU, resulted in an apparently stable planet of ~ 2 Earth masses forming in the
habitable zone. Migration-induced mixing of volatile-rich material from beyond
the `snowline' into the inner disk regions means that terrestrial planets that
form there are likely to be water-rich. We predict that hot--Jupiter systems
are likely to harbor water-rich terrestrial planets in their habitable zones.
These planets may be detected by future planet search missions.Comment: 18 pages, 13 figures. Higher resolution pdf available at
http://www.users.globalnet.co.uk/~mfogg/fogg_nelson2.pd
Open-loop characteristics of magnetic suspension systems using electromagnets mounted in a planar array
The open-loop characteristics of a Large-Gap Magnetic Suspension System (LGMSS) were studied and numerical results are presented. The LGMSS considered provides five-degree-of-freedom control. The suspended element is a cylinder that contains a core composed of permanent magnet material. The magnetic actuators are air core electromagnets mounted in a planar array. Configurations utilizing five, six, seven, and eight electromagnets were investigated and all configurations were found to be controllable from coil currents and observable from suspended element positions. Results indicate that increasing the number of coils has an insignificant effect on mode shapes and frequencies
Stability considerations for magnetic suspension systems using electromagnets mounted in a planar array
Mathematical models of a 5, 6, 7, and 8 coil large gap magnetic suspension system (MSDS) are presented. Some of the topics covered include: force and torque equations, reduction of state-space form, natural modes, origins of modes, effect of rotation in azimuth (yaw), future work, and n-coil ring conclusions
Development of Heterogeneous Photosensitized Transition Metal Oxide Water-Splitting Catalysts on Silica Support
The research presented in this manuscript describes the development of photosensitized inexpensive catalysts based on readily available materials. The investigation covers synthesis and characterization of photosensitizers based on porphyrins, mechanical and thermal coating of solid support with semiconducting transition metal oxides, photosensitization of the semiconducting layer, and characterization of the photoelectrochemical properties displayed by the new materials. The process of water oxidation is of primary interest here, with little emphasis put on reduction of protons to gaseous hydrogen. Photoelectrochemically produced protons serve as a probe of effectiveness of the catalysts. Several systems are described, and two catalysts are identified as the most efficient
Foolproof quick-release locking pin
Locking pin can be withdrawn only when stress on the joint is negligible. Pin consists of a forward-pointing sleeve, a spring-loaded sliding handle, and a sliding plunger. Plunger movement controls installation and withdrawal of pin
- …