scholarly journals Low-frequency fluid waves in fractures and pipes

Geophysics ◽  
2010 ◽  
Vol 75 (6) ◽  
pp. N97-N107 ◽  
Author(s):  
Valeri Korneev
Keyword(s):  
Guided Waves ◽  
Dominant Role ◽  
Low Frequency ◽  
Fluid Viscosity ◽  
Rock Permeability ◽  
Phase Velocities ◽  
Wave Effects ◽  
Channel Thickness ◽  
Strong Amplitude

Low-frequency analytical solutions have been obtained for phase velocities of symmetrical fluid waves within both an infinite fracture and a pipe filled with a viscous fluid. Three different fluid wave regimes can exist in such objects, depending on the various combinations of parameters, such as fluid density, fluid viscosity, walls shear modulus, channel thickness, and frequency. Equations for velocities of all these regimes have explicit forms and are verified by comparisons with the exact solutions. The dominant role of fractures in rock permeability at field scales and the strong amplitude and frequency effects of Stoneley guided waves suggest the importance of including these wave effects into poroelastic theories.

INTER-LANDAU-LEVEL TRANSITIONS AND ULTRAFAST DYNAMICS OF 2D MAGNETOEXCITONS

2004 ◽  
Vol 18 (27n29) ◽  
pp. 3847-3852 ◽  
Author(s):  
TIGRAN V. SHAHBAZYAN ◽  
NEIL A. FROMER ◽  
DANIEL S. CHEMLA
Keyword(s):  
Magnetic Field ◽  
Landau Level ◽  
Strong Field ◽  
Dominant Role ◽  
Ultrafast Dynamics ◽  
Many Body ◽  
Strong Amplitude ◽  
Negative Time ◽  
Electron Auger

We study the role of many-body correlations in the ultrafast dynamics of quantum well magnetoexcitons. In linear response, inter-Landau level transitions are suppressed if magnetic field is stronger than magnetoexciton binding energy. However, in nonlinear response, two-electron Auger processes remain unsuppressed even at very strong field. We show that Auger scattering plays a dominant role in the coherent exciton dynamics in strong magnetic field. We perform numerical calculations of four-wave-mixing (FWM) polarization which incorporate Auger processes nonperturbatively, and find a strong amplitude enhancement of the FWM signal accompanied with polarization oscillations at negative time delays. We identify these oscillations as quantum beats between dark two-exciton states related to each other via Auger processes.

Chronic Pain: Fundamental Scientific Considerations, Specifically for Legal Claims

2013 ◽  
Vol 18 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Robert J. Barth
Keyword(s):  
Health Outcomes ◽  
Pain Perception ◽  
Driving Forces ◽  
Psychological Treatment ◽  
Dominant Role ◽  
Meta Analysis ◽  
General Medicine ◽  
Pain Syndrome ◽  
Problematic Relationship

Abstract Scientific findings have indicated that psychological and social factors are the driving forces behind most chronic benign pain presentations, especially in a claim context, and are relevant to at least three of the AMA Guides publications: AMA Guides to Evaluation of Disease and Injury Causation, AMA Guides to Work Ability and Return to Work, and AMA Guides to the Evaluation of Permanent Impairment. The author reviews and summarizes studies that have identified the dominant role of financial, psychological, and other non–general medicine factors in patients who report low back pain. For example, one meta-analysis found that compensation results in an increase in pain perception and a reduction in the ability to benefit from medical and psychological treatment. Other studies have found a correlation between the level of compensation and health outcomes (greater compensation is associated with worse outcomes), and legal systems that discourage compensation for pain produce better health outcomes. One study found that, among persons with carpal tunnel syndrome, claimants had worse outcomes than nonclaimants despite receiving more treatment; another examined the problematic relationship between complex regional pain syndrome (CRPS) and compensation and found that cases of CRPS are dominated by legal claims, a disparity that highlights the dominant role of compensation. Workers’ compensation claimants are almost never evaluated for personality disorders or mental illness. The article concludes with recommendations that evaluators can consider in individual cases.

Calculation-and-experimental estimation of the role of the frequency ratio in changing the endurance at two-frequency deformation modes

2019 ◽  
Vol 85 (1(I)) ◽  
pp. 64-71 ◽  
Author(s):  
M. M. Gadenin
Keyword(s):  
High Frequency ◽  
Experimental Studies ◽  
Low Frequency ◽  
Reduction Factor ◽  
Single Frequency ◽  
Cyclic Loads ◽  
Small Ratio ◽  
Harmonic Components ◽  
Deformation Modes

The cycle configuration at two-frequency loading regimes depends on the number of parameters including the absolute values of the frequencies and amplitudes of the low-frequency and high-frequency loads added during this mode, the ratio of their frequencies and amplitudes, as well as the phase shift between these harmonic components, the latter having a significant effect only with a small ratio of frequencies. Presence of such two-frequency regimes or service loading conditions for parts of machines and structures schematized by them can significantly reduce their endurance. Using the results of experimental studies of changes in the endurance of a two-frequency loading of specimens of cyclically stable, cyclically softened and cyclically hardened steels under rigid conditions we have shown that decrease in the endurance under the aforementioned conditions depends on the ratio of frequencies and amplitudes of operation low-frequency low-cycle and high-frequency vibration stresses, and, moreover, the higher the level of the ratios of amplitudes and frequencies of those stacked harmonic processes of loading the greater the effect. It is shown that estimation of such a decrease in the endurance compared to a single frequency loading equal in the total stress (strains) amplitudes can be carried out using an exponential expression coupling those endurances through a parameter (reduction factor) containing the ratio of frequencies and amplitudes of operation cyclic loads and characteristic of the material. The reduction is illustrated by a set of calculation-experimental curves on the corresponding diagrams for each of the considered types of materials and compared with the experimental data.

НЕКОТОРЫЕ ОСОБЕННОСТИ РАСПРОСТРАНЕННОСТИ РЕСПИРАТОРНОЙ АЛЛЕРГИИ НА ЮГЕ РОССИИ

2019 ◽  
Author(s):  
D.Sh. Macharadze
Keyword(s):  
Dominant Role ◽  
Pollen Allergy ◽  
Respiratory Allergy ◽  
House Dust Mites ◽  
Dust Mites ◽  
The Past ◽  
Regional Features ◽  
Respiratory Allergies ◽  
Southern Russia

В обзорной статье приведены данные по распространенности респираторной аллергии - аллергического ринита и бронхиальной астмы на юге России, опубликованные за последние десятилетия. Показана доминирующая роль пыльцевой аллергии практически во всем южном регионе России. В Чеченской Республике у больных респираторной аллергией обнаружена сходная частота встречаемости сенсибилизации к клещам домашней пыли и пыльце злаковых трав (51,1 и 52,5 соответственно), тогда как сенсибилизация к пыльце амброзии и полыни встречалась в 3 раза реже (26,6 и 20,7 соответственно) по сравнению с соседними регионами юга России. Эти данные демонстрируют климатогеографические, экологические и другие региональные особенности в распространении респираторной аллергии.The review article presents data on the prevalence of respiratory allergy - allergic rhinitis and bronchial asthma in southern Russia, published over the past decades. The dominant role of pollen allergy is shown in almost the entire southern region of Russia. In the Chechen Republic, sensitization to house dust mites and grass pollen was found in patients with respiratory allergy equally (51.1 and 52.5, respectively), whereas ragweed and mugwort sensitization was 3 times less (26.6 and 20.7, respectively) compared with the neighboring regions of southern Russia. These data demonstrate climate-geographical, environmental and other regional features in the prevalence of respiratory allergies.

KEGAGALAN PRIVATISASI BUMN DI ERA REZIM ORDE BARU DALAM PERSPEKTIF EKONOMI POLITIK

Wacana Publik ◽  
2019 ◽  
Vol 12 (02) ◽  
Author(s):  
Syamsul Ma'arif
Keyword(s):  
Market Economy ◽  
Free Market ◽  
Dominant Role ◽  
The State ◽  
Early Years ◽  
New Order ◽  
Free Market Economy ◽  
Economic Sectors ◽  
Role Of The State

After had being carried out nationalization and hostility against west countries, the New Order regime made important decision to change Indonesia economic direction from etatism system to free market economy. A set of policies were taken in order private sector could play major role in economic. However, when another economic sectors were reformed substantially, effords to reform the State Owned Enterprises had failed. The State Owned Enterprise, in fact, remained to play dominant role like early years of guided democracy era. Role of the State Owned Enterprises was more and more powerfull). The main problem of reforms finally lied on reality that vested interest of bureaucrats (civil or military) was so large that could’nt been overcome. 

Conclusion

2018 ◽  
Author(s):  
Ildar Garipzanov
Keyword(s):  
Cultural History ◽  
Middle Ages ◽  
Late Antiquity ◽  
Western Europe ◽  
Dominant Role ◽  
Ninth Century ◽  
Sources Of Authority ◽  
History Of ◽  
Historical Periods

The concluding chapter highlights how the cultural history of graphic signs of authority in late antiquity and the early Middle Ages encapsulated the profound transformation of political culture in the Mediterranean and Europe from approximately the fourth to ninth centuries. It also reflects on the transcendent sources of authority in these historical periods, and the role of graphic signs in highlighting this connection. Finally, it warns that, despite the apparent dominant role of the sign of the cross and cruciform graphic devices in providing access to transcendent protection and support in ninth-century Western Europe, some people could still employ alternative graphic signs deriving from older occult traditions in their recourse to transcendent powers.

scholarly journals High Ripple-Density Resolution for Discriminating Between Rippled and Nonrippled Signals: Effect of Temporal Processing or Combination Products?

2021 ◽  
Vol 25 ◽  
pp. 233121652110101
Author(s):  
Dmitry I. Nechaev ◽  
Olga N. Milekhina ◽  
Marina S. Tomozova ◽  
Alexander Y. Supin
Keyword(s):  
Low Frequency ◽  
Noise Signal ◽  
Density Variation ◽  
Choice Procedure ◽  
Masker Level ◽  
Reference Signals ◽  
Forced Choice Procedure ◽  
The Mean ◽  
Density Resolution

The goal of the study was to investigate the role of combination products in the higher ripple-density resolution estimates obtained by discrimination between a spectrally rippled and a nonrippled noise signal than that obtained by discrimination between two rippled signals. To attain this goal, a noise band was used to mask the frequency band of expected low-frequency combination products. A three-alternative forced-choice procedure with adaptive ripple-density variation was used. The mean background (unmasked) ripple-density resolution was 9.8 ripples/oct for rippled reference signals and 21.8 ripples/oct for nonrippled reference signals. Low-frequency maskers reduced the ripple-density resolution. For masker levels from −10 to 10 dB re. signal, the ripple-density resolution for nonrippled reference signals was approximately twice as high as that for rippled reference signals. At a masker level as high as 20 dB re. signal, the ripple-density resolution decreased in both discrimination tasks. This result leads to the conclusion that low-frequency combination products are not responsible for the task-dependent difference in ripple-density resolution estimates.

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