INFLUENCE OF CHIRAL SYMMETRY ON THE CRITICAL BEHAVIOR OF STACKED TRIANGULAR ANTIFERROMAGNETS

1995 ◽  
Vol 09 (12) ◽  
pp. 1387-1407 ◽  
Author(s):  
H. WEBER ◽  
D. BECKMANN ◽  
J. WOSNITZA ◽  
H.v. LÖHNEYSEN ◽  
D. VISSER
Keyword(s):  
Specific Heat ◽  
Chiral Symmetry ◽  
Easy Axis ◽  
Critical Parameters ◽  
Zero Field ◽  
Amplitude Ratios ◽  
Multicritical Point ◽  
Theoretical Predictions ◽  
Universality Classes ◽  
Good Agreement

We review and extend our recent specific-heat results of three antiferromagnetic quasi-onedimensional magnets, CsMnBr 3, CsNiCl 3, and CsMnI 3, with chiral symmetry. In zero field, CsMnBr 3 exhibits an unusually large critical specific-heat exponent α in good agreement with predictions for chiral XY symmetry. The anisotropy-crossover exponent ɸ has been determined in low fields applied perpendicular to the c axis. ɸ is clearly smaller than unity and differs from theoretical predictions. For CsNiCl 3 we find a crossover in fields B||c from conventional universality behavior for B=0 to chiral Heisenberg behavior at the multicritical point BM=2.3 T and further to chiral XY behavior at still higher fields. The critical exponents and also the amplitude ratios of the specific heat are in excellent agreement with theory. A magnetic field applied 13° off the c axis modifies the phase diagram, but the critical parameters remain essentially unchanged. Finally, specific-heat measurements of CsMnI 3 confirm the crossover for easy-axis antiferromagnets with chiral symmetry and yield an exponent α=0.28±0.06 at the multicritical point. At 7 T, we find α=0.33±0.06. These values are again in very good agreement with the predictions for the chiral Heisenberg and chiral XY universality classes.

ANALYTIC STUDY ON SPECIFIC HEAT OF ICOSAHEDRAL Al-Mn-Pd QUASICRYSTALS

2008 ◽  
Vol 22 (17) ◽  
pp. 1653-1659 ◽  
Author(s):  
JIAN WANG ◽  
TIANYOU FAN
Keyword(s):  
Specific Heat ◽  
Explicit Formula ◽  
Analytic Study ◽  
Theoretical Predictions ◽  
Good Agreement

A simple and explicit formula for specific heat of icoschedral Al-Mn-Pd quasicrystals is obtained, theoretical predictions of which are in good agreement with that given by experiment.

scholarly journals A Generalized Approach for Evaluating the Mechanical Properties of Polymer Nanocomposites Reinforced with Spherical Fillers

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 830
Author(s):  
Julio Cesar Martinez-Garcia ◽  
Alexandre Serraïma-Ferrer ◽  
Aitor Lopeandía-Fernández ◽  
Marco Lattuada ◽  
Janak Sapkota ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polymeric Nanocomposites ◽  
Mechanical Reinforcement ◽  
Future Studies ◽  
Three Phase ◽  
Theoretical Predictions ◽  
Filler Network ◽  
New Research ◽  
Good Agreement ◽  
Research Avenue

In this work, the effective mechanical reinforcement of polymeric nanocomposites containing spherical particle fillers is predicted based on a generalized analytical three-phase-series-parallel model, considering the concepts of percolation and the interfacial glassy region. While the concept of percolation is solely taken as a contribution of the filler-network, we herein show that the glassy interphase between filler and matrix, which is often in the nanometers range, is also to be considered while interpreting enhanced mechanical properties of particulate filled polymeric nanocomposites. To demonstrate the relevance of the proposed generalized equation, we have fitted several experimental results which show a good agreement with theoretical predictions. Thus, the approach presented here can be valuable to elucidate new possible conceptual routes for the creation of new materials with fundamental technological applications and can open a new research avenue for future studies.

The Reduction of Bias Error in Transfer Function Estimates Using FFT-Based Analyzers

1984 ◽  
Vol 106 (1) ◽  
pp. 29-35 ◽  
Author(s):  
P. Cawley
Keyword(s):  
Transfer Function ◽  
Random Excitation ◽  
Analogue Computer ◽  
Bias Error ◽  
Testing Time ◽  
Theoretical Predictions ◽  
Set Up ◽  
Modal Mass ◽  
Time Required ◽  
Good Agreement

The susceptibility to bias error of two methods for computing transfer (frequency response) functions from spectra produced by FFT-based analyzers using random excitation has been investigated. Results from tests with an FFT analyzer on a single degree-of-freedom system set up on an analogue computer show good agreement with the theoretical predictions. It has been shown that, around resonance, the bias error in the transfer function estimate H2 (Syy/Sxy*) is considerably less than that in the more commonly used estimate, H1 (Sxy/Sxx). The record length, and hence the testing time, required for a given accuracy is reduced by over 50 percent if the H2 calculation procedure is used. The analysis has also shown that if shaker excitation is used on lightly damped structures with low modal mass, it is important to minimize the mass of the force gage and the moving element of the shaker.

Disorientation of Cs(62P1/2) atoms, induced in collisions with noble gases

1976 ◽  
Vol 54 (7) ◽  
pp. 748-752 ◽  
Author(s):  
B. Niewitecka ◽  
L. Krause
Keyword(s):  
Cross Sections ◽  
Noble Gas ◽  
Zero Magnetic Field ◽  
Zero Field ◽  
Buffer Gas ◽  
Resonance Fluorescence ◽  
Circularly Polarized ◽  
Low Field ◽  
Good Agreement ◽  
Gas Pressures

The disorientation of 62P1/2 cesium atoms, induced in collisions with noble gas atoms in their ground states, was systematically investigated by monitoring the depolarization of cesium resonance fluorescence in relation to noble gas pressures. The Cs atoms, contained together with a buffer gas in a fluorescence cell and located in zero magnetic field, were excited and oriented by irradiation with circularly polarized 8943 Å resonance radiation, and the resonance fluorescence, emitted in an approximately backward direction, was analyzed with respect to circular polarization. The experiments yielded the following disorientation cross sections which have been corrected for the effects of nuclear spin: Cs–He: 4.9 ± 0.7 Å2; Cs–Ne: 2.1 ± 0.3 Å2; Cs–Ar: 5.6 ± 0.8 Å2; Cs–Kr: 5.8 ± 0.9 Å2; Cs–Xe: 6.3 ± 0.9 Å2. The results are in good agreement with most of the available zero-field and low-field data.

The electrical resistivity of lithium-6

1961 ◽  
Vol 263 (1314) ◽  
pp. 407-419 ◽  
Keyword(s):  
Electrical Resistivity ◽  
Isotopic Composition ◽  
Specific Heat ◽  
Room Temperature ◽  
Natural Isotopic Composition ◽  
Square Roots ◽  
Conduction Electrons ◽  
Ionic Mass ◽  
Theoretical Predictions ◽  
Electrical Resistivities

The electrical resistivities of lithium -6 and lithium of natural isotopic composition have been studied between 4°K and room temperature. In addition, their absolute resistivities have been carefully compared at room temperature. These measurements show that the effect of ionic mass on electrical resistivity agrees with simple theoretical predictions, namely, that the properties of the conduction electrons in lithium do not depend on the mass of the ions, and that the characteristic lattice frequencies for the two pure isotopes are in the inverse ratio of the square roots of their ionic masses. A comparison with the specific heat results of Martin (1959, 1960), where the simple theory is found not to hold, indicates the possibility that anharmonic effects are present which affect the specific heat but not the electrical resistivity.

Theoretical Prediction of Motions of High-Speed Planing Boats in Waves

1978 ◽  
Vol 22 (03) ◽  
pp. 140-169
Author(s):  
Milton Martin
Keyword(s):  
High Speed ◽  
Damping Ratio ◽  
Nonlinear Effects ◽  
Theoretical Method ◽  
Valuable Insight ◽  
Response Characteristics ◽  
Theoretical Predictions ◽  
Response Amplitude Operators ◽  
Phase Angles ◽  
Good Agreement

A theoretical method is derived for predicting the linearized response characteristics of constant deadrise high-speed planing boats in head and following waves. Comparisons of the theoretical predictions of the pitch and heave response amplitude operators and phase angles with existing experimental data show reasonably good agreement for a wide variety of conditions of interest. It appears that nonlinear effects are more severe at a speed to length ratio of 6 than of, say, 4 or less, principally because of the reduction of the damping ratio of the boat with increasing speed, and the consequent increase in motions in the vicinity of the resonant encounter frequency. However, it is concluded that the linear theory can provide a simple and fast means of determining the effect of various parameters such as trim angle, deadrise, loading, and speed on the damping, natural frequency, and linearized response in waves, and that this can furnish valuable insight into the actual boat dynamics, even though the accurate predictions of large motions and peak accelerations would require a nonlinear analysis.

On Wall Effects in Cavity Flows

1984 ◽  
Vol 28 (01) ◽  
pp. 70-75
Author(s):  
C. C. Hsu
Keyword(s):  
Numerical Results ◽  
Cavity Flows ◽  
Two Dimensional ◽  
Wall Effects ◽  
Free Jet ◽  
Theoretical Predictions ◽  
Experimental Findings ◽  
Good Agreement

Simple wall correction rules for two-dimensional and nearly two-dimensional cavity flows in closed or free jet water tunnels, based on existing linearized analyses, are made. Numerical results calculated from these expressions are compared with existing experimental findings. The present theoretical predictions are, in general, in good agreement with data.

Modelling double diffusion in soils and materials

2018 ◽  
Vol 27 (5-6) ◽  
Author(s):  
Ariadne-Αnne Tsambali ◽  
Avraam A. Konstantinidis ◽  
Elias C. Aifantis
Keyword(s):  
Double Diffusion ◽  
Chloride Diffusion ◽  
Theoretical Predictions ◽  
Sandy Aquifers ◽  
Good Agreement

AbstractThe double diffusivity model proposed earlier by Aifantis and co-workers was applied in this work for modelling the diffusion of metals in sandy aquifers, as well as chloride diffusion in concrete specimens. The theoretical predictions are in very good agreement with the measured concentrations in all cases, showing that the model is capable of dealing with a large variety of double diffusivity problems.

scholarly journals Asymptotic analysis for personalized Web search

2010 ◽  
Vol 42 (02) ◽  
pp. 577-604 ◽  
Author(s):  
Yana Volkovich ◽  
Nelly Litvak
Keyword(s):  
Web Search ◽  
Power Laws ◽  
User Preference ◽  
Importance Measure ◽  
Web Documents ◽  
Original Definition ◽  
Theoretical Predictions ◽  
Heavy Tailed ◽  
Definition Of ◽  
Good Agreement

PageRank with personalization is used in Web search as an importance measure for Web documents. The goal of this paper is to characterize the tail behavior of the PageRank distribution in the Web and other complex networks characterized by power laws. To this end, we model the PageRank as a solution of a stochastic equationwhere theRis are distributed asR. This equation is inspired by the original definition of the PageRank. In particular,Nmodels the number of incoming links to a page, andBstays for the user preference. Assuming thatNorBare heavy tailed, we employ the theory of regular variation to obtain the asymptotic behavior ofRunder quite general assumptions on the involved random variables. Our theoretical predictions show good agreement with experimental data.

Some Limitations in Applying Classical EHD Film Thickness Formulas to a High-Speed Bearing

1981 ◽  
Vol 103 (2) ◽  
pp. 295-301 ◽  
Author(s):  
J. J. Coy ◽  
E. V. Zaretsky
Keyword(s):  
Film Thickness ◽  
High Speed ◽  
Heating Effects ◽  
Theoretical Predictions ◽  
Traction Fluid ◽  
Shear Heating ◽  
Thickness Measurements ◽  
Inner Race ◽  
Maximum Stresses ◽  
Good Agreement

Elastohydrodynamic film thickness was measured for a 20-mm ball bearing using the capacitance technique. The bearing was thrust loaded to 90, 448, and 778 N (20, 100, and 175 lb). The corresponding maximum stresses on the inner race were 1.28, 2.09, and 2.45 GPa (185,000, 303,000, and 356,000 psi). Test speeds ranged from 400 to 14,000 rpm. Film thickness measurements were taken with four different lubricants: (a) synthetic paraffinic, (b) synthetic paraffinic with additives, (c) neopentylpolyol (tetra) ester meeting MIL-L-23699A specifications, and (d) synthetic cycloaliphatic hydrocarbon traction fluid. The test bearing was mist lubricated. Test temperatures were 300, 338, and 393 K. The measured results were compared to theoretical predictions using the formulae of Grubin, Archard and Cowking, Dowson and Higginson, and Hamrock and Dowson. There was good agreement with theory at low dimensionless speed, but the film was much smaller than theory predicts at higher speeds. This was due to kinematic starvation and inlet shear heating effects. Comparisons with Chiu’s theory on starvation and Cheng’s theory on inlet shear heating were made.

Sign in / Sign up

Export Citation Format

Share Document