58,910 research outputs found
Method of recertifying a loaded bearing member
A method is described of recertifying a loaded bearing member using ultrasound testing to compensate for different equipment configurations and temperature conditions. The standard frequency F1 of a reference block is determined via an ultrasonic tone burst generated by a first pulsed phased locked loop (P2L2) equipment configuration. Once a lock point number S is determined for F1, the reference frequency F1a of the reference block is determined at this lock point number via a second P2L2 equipment configuration to permit an equipment offset compensation factor Fo1=((F1-F1a)/F1)(1000000) to be determined. Next, a reference frequency F2 of the unloaded bearing member is determined using a second P2L2 equipment configuration and is then compensated for equipment offset errors via the relationship F2+F2(Fo1)/1000000. A lock point number b is also determined for F2. A resonant frequency F3 is determined for the reference block using a third P2L2 equipment configuration to determine a second offset compensation factor F02=((F1-F3)/F1) 1000000. Next the resonant frequency F4 of the loaded bearing member is measured at lock point number b via the third P2L2 equipment configuration and the bolt load determined by the relationship (-1000000)CI(((F2-F4)/F2)-Fo2), wherein CI is a factor correlating measured frequency shift to the applied load. Temperature compensation is also performed at each point in the process
Solar wind sputtering effects in the Martian atmosphere
A Monte Carlo simulation of the sputtering of the upper atmosphere of Mars by the solar wind was performed. The calculated sputtering yields imply loss rates (molecules/cm square - sec escaping the planet) for carbon dioxide, carbon, and oxygen of R(CO2) = 2.6 X 1000000/cm square - sec, R(C) = 6.6 X 1000000/cm square - sec, and R(O) = 7.7 X 1000000/cm - sec. The total mass loss by sputtering is only about 10% of that due to chemical and photo-chemical processes, but sputtering provides a major exospheric sink for carbon. The erosion process described here preferentially removes the lighter components of the atmosphere. Calculations based on a Monte Carlo simulation suggest that for a model atmosphere, 97% of the N2 and 33% of the CO2 originally present may have been sputtered away over 4.5 X 10 to the 9th power y. In the same length of time the (15)N/(14)N isotopic ratio for the bulk atmosphere would have increased by a factor 1.7
The Florentin Smarandache Function S(n)
A program SMARAND has been designed to generate S(n) up to a preset limit N (N up to 1000000 has been used in some applications)
Once more on -vacua in dimensional QED and 3+1 dimensional gluodynamics
Two different but tightly connected problems, and strong CP violation
problems, are discussed in two different models which exhibit both asymptotic
freedom and confinement. One of them is the 3d Polyakov's model of compact QED
and the other is 4d gluodynamics. It is shown that although both these models
possess the long range interactions of the topological charges, only in the
former case physics does not depend on ; while the latter exhibits an
explicit - dependence. The crucial difference is due to the
observation, that the pseudoparticles of 4d gluodynamics possess an aditional
quantum number, apart of the topological charge .Comment: 15 page
Testing spontaneous localization theories with matter-wave interferometry
We propose to test the theory of continuous spontaneous localization (CSL) in
an all-optical time-domain Talbot-Lau interferometer for clusters with masses
exceeding 1000000 amu. By assessing the relevant environmental decoherence
mechanisms, as well as the growing size of the particles relative to the
grating fringes, we argue that it will be feasible to test the quantum
superposition principle in a mass range excluded by recent estimates of the CSL
effect.Comment: 4 pages, 3 figures; corresponds to published versio
Sub 20 nm Short Channel Carbon Nanotube Transistors
Carbon nanotube field-effect transistors with sub 20 nm long channels and
on/off current ratios of > 1000000 are demonstrated. Individual single-walled
carbon nanotubes with diameters ranging from 0.7 nm to 1.1 nm grown from
structured catalytic islands using chemical vapor deposition at 700 degree
Celsius form the channels. Electron beam lithography and a combination of HSQ,
calix[6]arene and PMMA e-beam resists were used to structure the short channels
and source and drain regions. The nanotube transistors display on-currents in
excess of 15 microA for drain-source biases of only 0.4 Volt.Comment: Nano Letters in pres
Correlations in Hot Dense Helium
Hot dense helium is studied with first-principles computer simulations. By
combining path integral Monte Carlo and density functional molecular dynamics,
a large temperature and density interval ranging from 1000 to 1000000 K and 0.4
to 5.4 g/cc becomes accessible to first-principles simulations and the changes
in the structure of dense hot fluids can be investigated. The focus of this
article are pair correlation functions between nuclei, between electrons, and
between electrons and nuclei. The density and temperature dependence of these
correlation functions is analyzed in order to describe the structure of the
dense fluid helium at extreme conditions.Comment: accepted for publication in Journal of Physics
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