Determination of the character of sediments and model verification using frequency‐dependent reflection coefficients

2001 ◽  
Vol 110 (5) ◽  
pp. 2767-2767
Author(s):  
Marcia J. Isakson ◽  
Egbert Hood ◽  
Nicholas P. Chotiros
Keyword(s):  
Model Verification ◽  
Reflection Coefficients ◽  
Frequency Dependent

VOC Fate Model Verification at Multiple Pulp Mill Wastewater Treatment Sites

1992 ◽  
Vol 26 (1-2) ◽  
pp. 407-415 ◽  
Author(s):  
D. A. Barton ◽  
J. J. McKeown ◽  
W. Chudyk
Keyword(s):  
Wastewater Treatment ◽  
Paper Industry ◽  
Pulp Mill ◽  
Pulp And Paper Industry ◽  
Model Verification ◽  
Initial Model ◽  
Gas Sampling ◽  
Treatment Processes ◽  
Fate Model

A model of organic compound removal by biological wastewater treatment processes receiving pulp and paper industry wastewaters has been developed and initial model verification performed at a single mill site. This paper presents the results of further model verification conducted at multiple mill sites, including replication of the original site. In addition, VOC losses at other unit processes are quantified. Activated sludge basin chloroform volatilization rates are predicted to within twelve percent of the measured rates. Predicted overall methanol removals are consistent with observed removals although difficulties encountered during off-gas sampling preclude determination of the extent of removal due to volatilization.

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.

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