36,096 research outputs found
Smooth-Particle Phase Stability with density and density-gradient potentials
Stable fluid and solid particle phases are essential to the simulation of
continuum fluids and solids using Smooth Particle Applied Mechanics. We show
that density-dependent potentials, such as Phi=(1/2)Sum (rho-rho_0)^2, along
with their corresponding constitutive relations, provide a simple means for
characterizing fluids and that a special stabilization potential, Phi=(1/2)Sum
(delrho)^2, not only stabilizes crystalline solid phases (or meshes) but also
provides a surface tension which is missing in the usual
density-dependent-potential approach. We illustrate these ideas for
two-dimensional square, triangular, and hexagonal lattices.Comment: 10 pages, 5 figure
Faster Calculation of Superquadric Shapes
Nonparametric methods of calculating points on the curve produce the recently introduced superquadric objects at great savings in time
An investigation of cotton for parachute cloth
This is a resume of the work of the Bureau of Standards on a cotton parachute cloth for use as a substitute for silk in the event of an emergency curtailing the supply. Cotton yarn of high strength in proportion to its weight and otherwise specially suitable for parachute cloth was developed. Cloth woven from this yarn in the bureau mill was equal or superior to parachute silk in strength and tear resistance, met the requirements with respect to air permeability, and weighed only a few tenths of an ounce per square yard more than the silk cloth. Practical trials of cotton parachutes carried out by the Navy Department clearly indicate that the cotton parachute closely approaches the silk parachute in performance as to rate of descent, opening time, strength and ability to function when stored in the pack for sixty days. The increase in weight of the equipment resulting from the use of cotton cloth instead of silk is considered to be well within practicable limits. A specification for cotton parachute cloth and the way in which the requirements of the specification have been met are given. Cotton yarns suitable for parachute cloth are now being woven commercially in the United States
Picosecond excitation of jet-cooled hydrogen-bonded systems: Dispersed fluorescence and time-resolved studies of methyl salicylatea
Long progressions involving frequency intervals of 180 cm^(−1) are observed in the fluoresence of MS for 3327.5 Å excitation. (AIP
Observation of intracavity absorption of molecules in supersonic beams
Intracavity absorption studies of DMT and I2 are reported at rotational and vibrational temperatures of <0.1 K and 16 K, respectively
Nonequilibrium Temperature and Thermometry in Heat-Conducting Phi-4 Models
We analyze temperature and thermometry for simple nonequilibrium
heat-conducting models. We show in detail, for both two- and three-dimensional
systems, that the ideal gas thermometer corresponds to the concept of a local
instantaneous mechanical kinetic temperature. For the Phi-4 models investigated
here the mechanical temperature closely approximates the local thermodynamic
equilibrium temperature. There is a significant difference between kinetic
temperature and the nonlocal configurational temperature. Neither obeys the
predictions of extended irreversible thermodynamics. Overall, we find that
kinetic temperature, as modeled and imposed by the Nos\'e-Hoover thermostats
developed in 1984, provides the simplest means for simulating, analyzing, and
understanding nonequilibrium heat flows.Comment: 20 pages with six figures, revised following review at Physical
Review
Liability for the Unauthorized Torts of Agents
No other part of the law of principal and agent is in such intolerable confusion as that which concerns the nature and extent of the liability of the principal for the tortious actions of the agent when done without either actual or apparent authority from the principal. There can be no question as to the liability of the principal for the agent\u27s tort that has been actually authorized or ratified, nor should there be any difficulty in holding the principal liable for such unauthorized torts of his agent as were committed under circumstances that induce a reasonable belief on- the part of the third party dealing with the agent that the principal had authorized the act in question. That is to say, the principal is estopped to deny responsibility for tortious acts done by the agent within the apparent scope of his authority. On this theory the principal becomes liable for a false representation made by his agent in negotiating a sale of his principal\u27s property. The principal may not have authorized such a misrepresentation, and may be personally wholly innocent of it; yet, having given to the agent authority to make a sale of the property the purchaser would have a reasonable ground for believing that the agent was also authorized to make such usual representations with reference to it as might be necessary to procure its sale
- …