Acoustics. Characterization of sources of structure-borne sound with respect to sound radiation from connected structures. Measurement of velocity at the contact points of machinery when resiliently mounted

2015 ◽  
2007 ◽  
Vol 35 (4) ◽  
pp. 721-723 ◽  
Author(s):  
D.F. Mierke ◽  
L. Mao ◽  
M. Pellegrini ◽  
A. Piserchio ◽  
J. Plati ◽  
...  

Over the years, the association of peptide ligands to Family B GPCRs (G-protein coupled receptors) has been characterized by a number of experimental and theoretical techniques. For the PTH (parathyroid hormone) ligand–receptor system, important insight has been provided by photoaffinity labelling experiments and the elucidation of direct contact points between ligand and receptor. Our research has focused on the structural elucidation of the receptor domains shown to be involved in the binding of PTH. Employing a combination of carefully designed receptor domains, solution-state NMR carried out in the presence of membrane mimetics and extensive computer simulations, we have obtained a well-resolved model of the ligand–receptor complex for PTH. Here, we review the development of this model and highlight some inherent limitations of the methods employed and their consequences on interpretation of the ligand–receptor model.


2004 ◽  
Vol 21 (4) ◽  
pp. 268-275 ◽  
Author(s):  
Michael Shapiro ◽  
Vladislav Dudko ◽  
Victor Royzen ◽  
Yuri Krichevets ◽  
Samuel Lekhtmakher ◽  
...  

2008 ◽  
Vol 368-372 ◽  
pp. 809-811 ◽  
Author(s):  
Hui Wang ◽  
Ling Ke Zeng

Mullite fiber porous ceramic was prepared by forced liquid displacement forming and using Mullite precursor sols as binders. SEM studies have shown that the uniformity of integral ceramic is good although the binder and fiber congregate slightly. Mullite precursor sols spread to films or congregate together in miniature. The mullite sol binders between fibers limit to the contact points and the redundant binders form flat film even if they are superfluous, and the pores were not built up even where the binders congregate badly. The results from mercury porosimetry testing of the mullite fiber porous ceramic showed the relationship of cumulative intrusion and diameter for mullite fiber porous ceramic using colloidal mullite binder, and the mean pore size is 45.6μm. The pore size distribution is very broad, from about 0.2 to 174.9μm.


2012 ◽  
Vol 98 (3) ◽  
pp. 384-391 ◽  
Author(s):  
H. A. Bonhoff ◽  
A. Eslami

The concept of source descriptor and coupling function is commonly recognized to form a rigorous basis for structure-borne sound source characterization. While this concept initially is valid for the single-point case only, it can be extended to sources with multi-point coupling by including the interface mobility approach. By considering a continuous interface that passes all contact points, the velocities, forces and mobilities are series expanded into interface orders by means of a spatial Fourier decomposition. The use of a continuous formulation for the multi-point case, however, can be problematic from a practical point of view. This paper discusses a reformulation of the interface mobility approach for a simplified calculation and clarified interpretation of the interface orders. With a discrete Fourier series as a basis for the interface mobility approach, the interface is reduced to a set of points and the interface orders are shown to describe the interplay of the data at the contact points. A discrete formulation furthermore yields simplified equations and a strict upper bound for the number of orders that have to be included, thus enhancing the practicability of interface mobilities for source characterization.


Author(s):  
D. Hitchen ◽  
S. Ghosh

The polarization hysteresis and current leakage characteristics of bismuth ferrite, BiFeO3 (BFO) thin films deposited by pulsed laser deposition was measured while varying the temperature from 80 - 300 K in increments of 10 K, to determine the feasibility of BFO for capacitive applications in memory storage devices. Data is compared to the performance of prototypic ferroelectric barium strontium titanate, BaxSr1-xTiO3 (BST) under similar conditions. Finding contacts on the BFO samples that exhibited acceptable dielectric properties was challenging; and once identified, the polarization characteristics between them varied greatly. However, the non-uniformity among the contact points within each sample suggests that either the samples were defective (by contamination or growth process), or that the deposition process of the contacts may have undermined the functionality of the devices. Subjected to increasing temperatures, BFO's polarization improved, and though its polarizability was shown to be inferior to BST, the dielectric loss was less.


2020 ◽  
Vol 69 (1) ◽  
pp. 44-54 ◽  
Author(s):  
Carmen Delcira Vega ◽  
Ingrid Teich ◽  
Maria Cristina Acosta ◽  
Diego Lopez Lauenstein ◽  
Aníbal Ramón Verga ◽  
...  

AbstractThe Gran Chaco is the largest dry forest in South America. One of the key taxa of this biome is the genus Prosopis (Fabaceae) which contains several economically important species. One of the characteristics of this genus is its natural capacity to exchange genetic information among congeneric species, generating zones of high morphological and genetic variability at contact points. The study and management of these contact areas can contribute to the dynamic conservation of these native genetic resources. In this study, we analysed three sites within a gradient of land aridity, where P. nigra and P. alba grow in sympatry and apparently hybridize. This is the first study performed in both, Prosopis pure sites and hybrid swarm, which includes a spatially explicit approach and simultaneously analyses fruit and leaf morphological variation, together with molecular information (microsatellites markers). We performed a multivariate morphological analysis, Bayesian genetic clustering and multivariate associations between genetic and morphological variability in the pure parental populations and in the hybrid swarm, considering possible spatial autocorrelation. Bayesian cluster analysis revealed two distinct groups corresponding to each species, differentiating the pure morphotypes from sites 1 and 2. Site 3, corresponding to the hybrid swarm, was composed of pure P. alba and P. nigra trees and hybrid individuals. We found morphological and molecular evidence of hybridization between P. alba and P. nigra, and detected novel phenotypes in the hybrid site.


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