6,589 research outputs found
Inexpensive high-temperature furnace for thermocouple calibration
New furnace calibrates unknown thermocouple by comparing its electrical output to a reference thermocouple /previously calibrated by optical pyrometry/, as both are heated simultaneously. Thermocouples may be radioactive, thus heat source must be accessible by remote manipulation and inspection measurements. Advantages of furnace operation are cited
High-temperature rapid-response thermocouple for reducing atmospheres
Thermocouple measures continuously in flowing gaseous hydrogen at temperatures up to 4000 deg F, in environments made hazardous by radiation, and where rapid response and calibration reproducibility are critically important. Thermocouple wires extend continuously, without splice or foreign material, from cold junction to probe's tip
Quasi-homologous spherically symmetric branes and their symmetry breaking
We revisit the dynamical system based approach of spherically symmetric
vacuum braneworlds, pointing out and studying the existence of a transcritical
bifurcation as the dark pressure parameter changes its sign, we analyze some
consequences of not discard the brane cosmological constant. For instance, it
is noteworthy that the existence of an isothermal state equation between the
dark fluid parameters cannot be obtained via the requirement of a
quasi-homologous symmetry of the vacuum.Comment: 20 pages, 12 figures. To appear in EPJ
Towards an hybrid compactification with a scalar-tensor global cosmic string
We derive a solution of the gravitational equations which leads to a
braneworld scenario in six dimensions using a global cosmic string solution in
a low energy effective string theory framework. The final spacetime is composed
by one warped brane with topology and a power
law warp factor, and one noncompact extra dimension transverse to the brane. By
looking at the current experimental bounds, we find a range of parameters in
which, if the on-brane dimension has an acceptable size, it does not solve the
hierarchy problem. In another example this problem is smoothed by the
Brans-Dicke parameter.Comment: RevTex, 7 pages. New version to be published in the JCAP (2008
Brane Cosmic String Compactification in Brans-Dicke Theory
We investigate an alternative compactification of extra dimensions using
local cosmic string in the Brans-Dicke gravity framework. In the context of
dynamical systems it is possible to show that there exist a stable field
configuration for the Einstein-Brans-Dicke equations. We explore the analogies
between this particular model and the Randall-Sundrum scenario.Comment: RevTex, 5 pages, no figures. To appear in the Physical Review
Solution for a local straight cosmic string in the braneworld gravity
In this work we deal with the spacetime shaped by a straight cosmic string,
emerging from local gauge theories, in the braneworld gravity context. We
search for physical consequences of string features due to the modified
gravitational scenario encoded in the projected gravitational equations. It is
shown that cosmic strings in braneworld gravity may present significant
differences when compared to the general relativity predictions since its
linear density is modified and the deficit angle produced by the cosmic string
is attenuated. Furthermore, the existence of cosmic strings in that scenario
requires a strong restriction to the braneworld tension: , in Planck units.Comment: 7 pages, 3 figure
Static Domain Wall in the Braneworld gravity
In this paper we consider a static domain wall inside a 3-brane. Differently
of the standard achievement obtained in General Relativity, the analysis
performed here gives a consistency condition for the existence of static domain
walls in a braneworld gravitational scenario. It is also shown the behavior of
the domain wall gravitational field in the newtonian limit.Comment: 11 pages, no figures, accepted for publication in EPJ
Nutritional and cultural aspects of plant species selection for a controlled ecological life support system
The feasibility of using higher plants in a controlled ecological life support system is discussed. Aspects of this system considered important in the use of higher plants include: limited energy, space, and mass, and problems relating to cultivation and management of plants, food processing, the psychological impact of vegetarian diets, and plant propagation. A total of 115 higher plant species are compared based on 21 selection criteria
Questing for Algebraic Mass Dimension One Spinor Fields
This work deals with new classes of spinors of mass dimension one in
Minkowski spacetime. In order to accomplish it, the Lounesto classification
scheme and the inversion theorem are going to be used. The algebraic framework
shall be revisited by explicating the central point performed by the Fierz
aggregate. Then the spinor classification is generalized in order to encompass
the new mass dimension one spinors. The spinor operator is shown to play a
prominent role to engender the new mass dimension one spinors, accordingly.Comment: 7 pages, final version to appear in Eur. Phys. J.
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