29,234 research outputs found
Toward 'generalized control theory'
Optimization problems in control theory in terms of criterion function, controller, and information available to controlle
An informal paper on large-scale dynamic systems
Large scale systems are defined as systems requiring more than one decision maker to control the system. Decentralized control and decomposition are discussed for large scale dynamic systems. Information and many-person decision problems are analyzed
A suspended microchannel with integrated temperature sensors for high-pressure flow studies
A freestanding microchannel, with integrated temperature sensors, has been developed for high-pressure flow studies. These microchannels are approximately 20μm x 2μm x 4400μm, and are suspended above 80 μm deep cavities, bulk micromachined using BrF3 dry etch. The calibration of the lightly boron-doped thermistor-type sensors shows that the resistance sensitivity of these integrated sensors is parabolic with respect to temperature and linear with respect to pressure. Volumetric flow rates of N2 in the microchannel were measured at inlet pressures up to 578 psig. The discrepancy between the data and theory results from the flow acceleration in a channel, the non-parabolic velocity profile, and the bulging of the channel. Bulging effects were evaluated by using incompressible water flow measurements, which also measures 1.045x10^-3N-s/m^2 for the viscosity of DI water. The temperature data from sensors on the channel shows the heating of the channel due to the friction generated by the high-pressure flow inside
Multiple Chern-Simons Fields on a Torus
Intertwined multiple Chern-Simons gauge fields induce matrix statistics among
particles. We analyse this theory on a torus, focusing on the vacuum structure
and the Hilbert space. The theory can be mimicked, although not completely, by
an effective theory with one Chern-Simons gauge field. The correspondence
between the Wilson line integrals, vacuum degeneracy and wave functions for
these two theories are discussed. Further, it is obtained in both of these
cases that the two total momenta and Hamiltonian commute only in the physical
Hilbert space.Comment: 20 pages, UMN-TH-1128/93, plain Te
Materials thermal and thermoradiative properties/characterization technology
Reliable properties data on well characterized materials are necessary for design of experiments and interpretation of experimental results. The activities of CINDAS to provide data bases and predict properties are discussed. An understanding of emissivity behavior is important in order to select appropriate methods for non-contact temperature determination. Related technical issues are identified and recommendations are offered
Detection of changes in the characteristics of a Gauss-Markov process
Sequential detection of changes in Gauss-Markov process achieved through probability ratio tes
Analysis and design of integration formulas for a random integrand
Analysis of integration formulas and procedure for designing optimal integration formul
On the limits of measuring the bulge and disk properties of local and high-redshift massive galaxies
A considerable fraction of the massive quiescent galaxies at \emph{z}
2, which are known to be much more compact than galaxies of
comparable mass today, appear to have a disk. How well can we measure the bulge
and disk properties of these systems? We simulate two-component model galaxies
in order to systematically quantify the effects of non-homology in structures
and the methods employed. We employ empirical scaling relations to produce
realistic-looking local galaxies with a uniform and wide range of
bulge-to-total ratios (), and then rescale them to mimic the
signal-to-noise ratios and sizes of observed galaxies at \emph{z} 2.
This provides the most complete set of simulations to date for which we can
examine the robustness of two-component decomposition of compact disk galaxies
at different . We confirm that the size of these massive, compact galaxies
can be measured robustly using a single S\'{e}rsic fit. We can measure
accurately without imposing any constraints on the light profile shape of the
bulge, but, due to the small angular sizes of bulges at high redshift, their
detailed properties can only be recovered for galaxies with \gax\ 0.2.
The disk component, by contrast, can be measured with little difficulty
Anomalous physical properties of underdoped weak-ferromagnetic superconductor RuSrEuCuO
Similar to the optimal-doped, weak-ferromagnetic (WFM induced by canted
antiferromagnetism, T = 131 K) and superconducting (T = 56 K)
RuSrGdCuO, the underdoped RuSrEuCuO
(T = 133 K, T = 36 K) also exhibited a spontaneous vortex state
(SVS) between 16 K and 36 K. The low field (20 G) superconducting
hysteresis loop indicates a weak and narrow Meissner state region of average
lower critical field B(T) = B(0)[1 -
(T/T)], with B(0) = 7 G and T = 16 K. The
vortex melting transition (T = 21 K) below T obtained from
the broad resistivity drop and the onset of diamagnetic signal indicates a
vortex liquid region due to the coexistence and interplay between
superconductivity and WFM order. No visible jump in specific heat was observed
near T for Eu- and Gd-compound. This is not surprising, since the
electronic specific heat is easily overshadowed by the large phonon and
weak-ferromagnetic contributions. Furthermore, a broad resistivity transition
due to low vortex melting temperature would also lead to a correspondingly
reduced height of any specific heat jump. Finally, with the baseline from the
nonmagnetic Eu-compound, specific heat data analysis confirms the magnetic
entropy associated with antiferromagnetic ordering of Gd (J = S = 7/2)
at 2.5 K to be close to ln8 as expected.Comment: 7 figure
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