651 research outputs found
Nagel scaling and relaxation in the kinetic Ising model on a n-isotopic chain
The kinetic Ising model on a n-isotopic chain is considered in the framework
of Glauber dynamics. The chain is composed of N segments with n sites, each one
occupied by a different isotope. Due to the isotopic mass difference, the n
spins in each segment have different relaxation times in the absence of the
interactions, and consequently the dynamics of the system is governed by
multiple relaxation mechanisms. The solution is obtained in closed form for
arbitrary n, by reducing the problem to a set of n coupled equations, and it is
shown rigorously that the critical exponent z is equal to 2. Explicit results
are obtained numerically for any temperature and it is also shown that the
dynamic susceptibility satisfies the new scaling (Nagel scaling) proposed for
glass-forming liquids. This is in agreement with our recent results (L. L.
Goncalves, M. Lopez de Haro, J. Taguena-Martinez and R. B. Stinchcombe, Phys.
Rev. Lett. 84, 1507 (2000)), which relate this new scaling function to multiple
relaxation processes.Comment: 4 pages, 2 figures, presented at Ising Centennial Colloquium, to be
published in the Proceedings (Brazilian Journal of Physics.
ROBERT E. KENNEDY LIBRARY CAL POLY, SAN LUIS OBISPO FIRE PROTECTION ANALYSIS FPE CULMINATING PROJECT
California State University has acquired fire protection services to conduct a survey of and produce a fire protection report that analyzes the current condition of the existing Robert E. Kennedy Library on the Cal Poly campus. The prescriptive analysis of the Library is based on the 2010 California Building- the analysis considers the building a new building and will not consider the building provision for existing buildings as permitted by Chapter 34 of the CBC. A performance-based design using FDS is also analyzed to determine the tenability advantages of providing fire sprinklers within the Library. Non-conforming conditions include, among others, exit extension has non-common use areas opening into the exit extension (i.e., electrical room), and visible/ audible notification coverage deficiencies. The performance-based design fire is based on a âfree burnâ test conducted using oxygen consumption calorimetry. The tested material included parallel metal open bookshelves with paper material stacked on their shelves. The data from the test produced maximum heat release rate of 1.6 MW. This data was extrapolated to define a fire scenario that produced a 6.2 MW heat release rate based on the configuration of bookshelves and the plentiful amount of fuel (i.e., paper) in the Library stack areas. Based on the time to sprinkler activation, a sprinkler controlled fire is also modeled to compare to the non-sprinklered building condition. It was determined that a 1.1 MW fire was the maximum heat release rate of a sprinklered controlled fire. From the performance-based model it was determined that a sprinklered building improves the tenability conditions and increases the Available Safe Egress Time for the occupants in the building. All in all, it is recommended that the Library be provided with a sprinkler system. It is also recommended that the Library be provided with visual/audible notification appliances in accordance with NFPA 72. It is also recommended that an EVAC system be provided as required by the CBC. Additional recommendations are described within this report. The appendix of this fire protection report includes a proposed sprinkler design for the Library, a fire life safety plan, and a design for the audible/visible notification appliances of the second floor (fire floor)
Technique for detecting warm-hot intergalactic gas in quasar UV spectra
The ionizing spectral energy distribution of quasars exhibits a steepening of
the distribution shortward of ~ 1200 A. The change of the power-law index from
approximately -1 (near-UV) to -2 (far-UV) has so far been interpreted as being
intrinsic to quasars. We consider the possibility that the steepening may
result from a tenuous absorption component that is anticorrelated with large
mass overdensities. UV sensitive satellites, whose detectors can extend down to
1000 A, can set a useful limit to such an absorption component through the
search of a flux increase in the window 1050-1190 A (observer frame) with
respect to an extrapolation of the continuum above 1230 A. Since the recent
FUSE or HST-STIS data do not show any obvious discontinuity in this region,
this effectively rules out the possibility that intergalactic HI absorption is
very important, and it is concluded that most if not all of the steepening is
intrinsic to quasars. A smaller flux discontinuity of order 1% cannot, however,
be ruled out yet and would still be consistent with the warm-hot intergalactic
component if it amounts to 30% of the baryonic mass, as predicted by some
models of large scale structure formation, provided its temperature lies around
10^{5.5} K.Comment: 13 pages, 5 figures and 1 table, accepted for publication in
Astrophysical Journal, typos corrected and correction for the faulty scaling
of variable n_H^0 with redshif
Binding of retinoids to uteroglobin
AbstractUteroglobin, a progesterone-binding secretory protein, was shown to bind retinoic acid and retinol in a non-saturable manner, at least up to concentrations of retinoids of 20 ÎŒM. Binding is increased about 10-fold by previous reduction of uteroglobin with 10 mM dithothreitol and it is not affected by previous saturation of the progesterone binding site, suggesting different binding sites for the steroid and the retinoids. The results are discussed in relation to a possible physiological role for this protein
Technique for detecting warm-hot intergalactic gas in quasar UV spectra
The ionizing spectral energy distribution of quasars exhibits a steepening of
the distribution shortward of ~ 1200 A. The change of the power-law index from
approximately -1 (near-UV) to -2 (far-UV) has so far been interpreted as being
intrinsic to quasars. We consider the possibility that the steepening may
result from a tenuous absorption component that is anticorrelated with large
mass overdensities. UV sensitive satellites, whose detectors can extend down to
1000 A, can set a useful limit to such an absorption component through the
search of a flux increase in the window 1050-1190 A (observer frame) with
respect to an extrapolation of the continuum above 1230 A. Since the recent
FUSE or HST-STIS data do not show any obvious discontinuity in this region,
this effectively rules out the possibility that intergalactic HI absorption is
very important, and it is concluded that most if not all of the steepening is
intrinsic to quasars. A smaller flux discontinuity of order 1% cannot, however,
be ruled out yet and would still be consistent with the warm-hot intergalactic
component if it amounts to 30% of the baryonic mass, as predicted by some
models of large scale structure formation, provided its temperature lies around
10^{5.5} K.Comment: 13 pages, 5 figures and 1 table, accepted for publication in
Astrophysical Journal, typos corrected and correction for the faulty scaling
of variable n_H^0 with redshif
No, nonada, monada, en el pensamiento contemporaneo en lengua espanola
Jose Gaos's thorough analysis concerning the logical origin of the grammatical particle "no" establishes as its ultimate ground no meaning functions but sympathetic acts of love and hate. This proposal enables me a new approach to Unamuno's opposite attempt, namely: that of conceiving the negation as the center and core of theoretical reason, of objectifying conscience as opposed to the trends of craving which in origin are infinitely affirmative. Unamuno's concept of "nonada" (something next to nothing) involves a remarkable contention with the axiom that to be a part, a mere part, a fleeting particle of reality, is ultimately nothing
Experimental Robot Model Adjustments Based on Force-Torque Sensor Information
The computational complexity of humanoid robot balance control is reduced through the application of simplified kinematics and dynamics models. However, these simplifications lead to the introduction of errors that add to other inherent electro-mechanic inaccuracies and affect the robotic system. Linear control systems deal with these inaccuracies if they operate around a specific working point but are less precise if they do not. This work presents a model improvement based on the Linear Inverted Pendulum Model (LIPM) to be applied in a non-linear control system. The aim is to minimize the control error and reduce robot oscillations for multiple working points. The new model, named the Dynamic LIPM (DLIPM), is used to plan the robot behavior with respect to changes in the balance status denoted by the zero moment point (ZMP). Thanks to the use of information from force-torque sensors, an experimental procedure has been applied to characterize the inaccuracies and introduce them into the new model. The experiments consist of balance perturbations similar to those of push-recovery trials, in which step-shaped ZMP variations are produced. The results show that the responses of the robot with respect to balance perturbations are more precise and the mechanical oscillations are reduced without comprising robot dynamicsThe research leading to these results received funding from the RoboCity2030-III-CM project (RobĂłtica aplicada a la mejora de la calidad de vida de los ciudadanos. Fase III; S2013/MIT-2748), funded by Programas de Actividades I+D en la Comunidad de Madrid and cofunded by Structural Funds of the EU
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