Frequency-dependent hydrodynamic inductance and the determination of the thermal and quantum noise of a superfluid gyroscope

2005 ◽  
Vol 71 (13) ◽  
Author(s):  
Talso Chui ◽  
Konstantin Penanen
Keyword(s):  
Quantum Noise ◽  
Frequency Dependent

A method for determination of frequency‐dependent effective scatterer number density

1994 ◽  
Vol 95 (1) ◽  
pp. 77-85 ◽  
Author(s):  
Jian‐Feng Chen ◽  
Ernest L. Madsen ◽  
James A. Zagzebski
Keyword(s):  
Number Density ◽  
Frequency Dependent

scholarly journals Rigid-Earth Nutation Models

2000 ◽  
Vol 180 ◽  
pp. 190-195
Author(s):  
J. Souchay
Keyword(s):  
Transfer Function ◽  
Rigid Body ◽  
Earth Model ◽  
High Quality ◽  
Frequency Dependent ◽  
Relative Improvement ◽  
The Earth ◽  
Rigid Earth

AbstractDespite the fact that the main causes of the differences between the observed Earth nutation and that derived from analytical calculations come from geophysical effects associated with nonrigidity (core flattening, core-mantle interactions, oceans, etc…), efforts have been made recently to compute the nutation of the Earth when it is considered to be a rigid body, giving birth to several “rigid Earth nutation models.” The reason for these efforts is that any coefficient of nutation for a realistic Earth (including effects due to nonrigidity) is calculated starting from a coefficient for a rigid-Earth model, using a frequency-dependent transfer function. Therefore it is important to achieve high quality in the determination of rigid-Earth nutation coefficients, in order to isolate the nonrigid effects still not well-modeled.After reviewing various rigid-Earth nutation models which have been established recently and their relative improvement with respect to older ones, we discuss their specifics and their degree of agreement.

scholarly journals Rheometer enabled study of cartilage frequency-dependent properties

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Stefano Perni ◽  
Polina Prokopovich
Keyword(s):  
Applied Load ◽  
Cost Effective ◽  
Constant Load ◽  
Hydraulic Permeability ◽  
Frequency Dependent ◽  
Shear Moduli ◽  
Tissue Replacement ◽  
Cost Effective Approach ◽  
The Impact

AbstractDespite the well-established dependence of cartilage mechanical properties on the frequency of the applied load, most research in the field is carried out in either load-free or constant load conditions because of the complexity of the equipment required for the determination of time-dependent properties. These simpler analyses provide a limited representation of cartilage properties thus greatly reducing the impact of the information gathered hindering the understanding of the mechanisms involved in this tissue replacement, development and pathology. More complex techniques could represent better investigative methods, but their uptake in cartilage research is limited by the highly specialised training required and cost of the equipment. There is, therefore, a clear need for alternative experimental approaches to cartilage testing to be deployed in research and clinical settings using more user-friendly and financial accessible devices. Frequency dependent material properties can be determined through rheometry that is an easy to use requiring a relatively inexpensive device; we present how a commercial rheometer can be adapted to determine the viscoelastic properties of articular cartilage. Frequency-sweep tests were run at various applied normal loads on immature, mature and trypsinased (as model of osteoarthritis) cartilage samples to determine the dynamic shear moduli (G*, G′ G″) of the tissues. Moduli increased with increasing frequency and applied load; mature cartilage had generally the highest moduli and GAG depleted samples the lowest. Hydraulic permeability (KH) was estimated from the rheological data and decreased with applied load; GAG depleted cartilage exhibited higher hydraulic permeability than either immature or mature tissues. The rheometer-based methodology developed was validated by the close comparison of the rheometer-obtained cartilage characteristics (G*, G′, G″, KH) with results obtained with more complex testing techniques available in literature. Rheometry is relatively simpler and does not require highly capital intensive machinery and staff training is more accessible; thus the use of a rheometer would represent a cost-effective approach for the determination of frequency-dependent properties of cartilage for more comprehensive and impactful results for both healthcare professional and R&D.

ACCURATE ANALYTICAL MODELING OF FREQUENCY DEPENDENT LOOP SELF-INDUCTANCE

2008 ◽  
Vol 17 (01) ◽  
pp. 77-93
Author(s):  
MOSIN MONDAL ◽  
YEHIA MASSOUD
Keyword(s):  
Integrated Circuits ◽  
Frequency Dependence ◽  
Intermediate Frequency ◽  
Propagation Delay ◽  
Computationally Efficient ◽  
Frequency Dependent ◽  
Wide Range ◽  
Global Interconnects ◽  
Very High Frequencies

Parasitic inductance of global interconnects has gained much attention in the recent past since the inductance can no longer be neglected due to different design and fabrication issues. This has led to a paradigm shift from RC to RLC modeling of global interconnects in modern integrated circuits. However, the extraction of inductance is often expensive and presents a bottleneck in performing RLC analysis of interconnects. Unlike capacitance, the frequency dependence of current distribution through return paths present a major challenge in inductance extraction. In this paper, an efficient analytical model of frequency dependent self-inductance that can be applied to model a wide range of real design scenarios was presented. The model is based on the determination of the inductances at low and very high frequencies, an intermediate frequency point and the corresponding slope of the inductance frequency response. It is demonstrate that the approach is computationally efficient and it produces accurate values of frequency dependent inductance. It is also investigate how the frequency dependence of loop self-inductance affects the RLC delay and show that the pessimism in RLC propagation delay estimation could be as high as 49% if the frequency dependence of inductance is not considered properly. Thus, realistic (less pessimistic) delay values can be obtained using our model, leading to improved system performance.

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