scholarly journals Modelling of nonlinear wave scattering in a delaminated elastic bar

2015 ◽  
Vol 471 (2183) ◽  
pp. 20150584 ◽  
Author(s):  
K. R. Khusnutdinova ◽  
M. R. Tranter
Keyword(s):  
Solitary Wave ◽  
Multiple Scales ◽  
Vries Equation ◽  
Numerical Approach ◽  
Layered Structures ◽  
Scattering Transform ◽  
Elastic Bar ◽  
Poor Adhesion ◽  
Integrability Theory

Integrity of layered structures, extensively used in modern industry, strongly depends on the quality of their interfaces; poor adhesion or delamination can lead to a failure of the structure. Can nonlinear waves help us to control the quality of layered structures? In this paper, we numerically model the dynamics of a long longitudinal strain solitary wave in a split, symmetric layered bar. The recently developed analytical approach, based on matching two asymptotic multiple-scales expansions and the integrability theory of the Korteweg–de Vries equation by the inverse scattering transform, is used to develop an effective semi-analytical numerical approach for these types of problems. We also employ a direct finite-difference method and compare the numerical results with each other, and with the analytical predictions. The numerical modelling confirms that delamination causes fission of an incident solitary wave and, thus, can be used to detect the defect.

On the modulation of water waves on shear flows

1976 ◽  
Vol 347 (1651) ◽  
pp. 537-546 ◽  
Keyword(s):  
Water Waves ◽  
Multiple Scales ◽  
Method Of Multiple Scales ◽  
Vries Equation ◽  
Harmonic Wave ◽  
Short Wave ◽  
Long Wave ◽  
Stokes Waves ◽  
The Stability ◽  
Wave Limit

The method of multiple scales is used to examine the slow modulation of a harmonic wave moving over the surface of a two dimensional channel. The flow is assumed inviscid and incompressible, but the basic flow takes the form of an arbitrary shear. The appropriate nonlinear Schrödinger equation is derived with coefficients that depend, in a complicated way, on the shear. It is shown that this equation agrees with previous work for the case of no shear; it also agrees in the long wave limit with the appropriate short wave limit of the Korteweg-de Vries equation, the shear being arbitrary. Finally, it is remarked that the stability of Stokes waves over any shear can be examined by using the results derived here.

scholarly journals A Numerical Approach for Sound Quality of Vehicle Doors

2020 ◽  
Vol 25 (1) ◽  
pp. 9-16
Author(s):  
Erkut Yalçın ◽  
Halil Bilal ◽  
Ayhan Yağcı ◽  
Haluk Erol
Keyword(s):  
Sound Pressure ◽  
Sound Quality ◽  
Numerical Approach ◽  
Design Sensitivity ◽  
Point Of View ◽  
Vehicle Body ◽  
Fem Model ◽  
Body Development ◽  
Design Variables

A Vibro-Acoustic Finite Element Method (FEM) model capable of calculating the transient sound pressure generated by the door slam of a vehicle was developed in this study. A design sensitivity analysis (DSA) was performed for investigating the effects of major design variables on the related sound quality metrics. The methodology was developed using a sedan-car and its FEM model. This paper shows that a Computer Aided Engineering (CAE) model can be used as a rather powerful tool for giving design change decisions for the door components from sound quality point of view during vehicle body development according to psychoacoustic parameters.

Survival analysis at multiple scales for the modeling of track geometry deterioration

2017 ◽  
Vol 232 (3) ◽  
pp. 842-850 ◽  
Author(s):  
Negin Alemazkoor ◽  
Conrad J Ruppert ◽  
Hadi Meidani
Keyword(s):  
Survival Analysis ◽  
Multiple Scales ◽  
Fine Scale ◽  
Coarse Scale ◽  
Track Geometry ◽  
Time Period ◽  
Scale Models ◽  
Optimal Maintenance ◽  
Maintenance Decisions

Defects in track geometry have a notable impact on the safety of rail transportation. In order to make the optimal maintenance decisions to ensure the safety and efficiency of railroads, it is necessary to analyze the track geometry defects and develop reliable defect deterioration models. In general, standard deterioration models are typically developed for a segment of track. As a result, these coarse-scale deterioration models may fail to predict whether the isolated defects in a segment will exceed the safety limits after a given time period or not. In this paper, survival analysis is used to model the probability of exceeding the safety limits of the isolated defects. These fine-scale models are then used to calculate the probability of whether each segment of the track will require maintenance after a given time period. The model validation results show that the prediction quality of the coarse-scale segment-based models can be improved by exploiting information from the fine-scale defect-based deterioration models.

The Floral Microbiome: Plant, Pollinator, and Microbial Perspectives

2020 ◽  
Vol 51 (1) ◽  
pp. 363-386 ◽  
Author(s):  
Rachel L. Vannette
Keyword(s):  
Multiple Scales ◽  
Ecological Processes ◽  
Pollinator Attraction ◽  
Plant Variation ◽  
Floral Visitors ◽  
Floral Phenotype ◽  
Bacteria And Fungi ◽  
Plant Pollinator ◽  
Microbial Effects

Flowers at times host abundant and specialized communities of bacteria and fungi that influence floral phenotypes and interactions with pollinators. Ecological processes drive variation in microbial abundance and composition at multiple scales, including among plant species, among flower tissues, and among flowers on the same plant. Variation in microbial effects on floral phenotype suggests that microbial metabolites could cue the presence or quality of rewards for pollinators, but most plants are unlikely to rely on microbes for pollinator attraction or reproduction. From a microbial perspective, flowers offer opportunities to disperse between habitats, but microbial species differ in requirements for and benefits received from such dispersal. The extent to which floral microbes shape the evolution of floral traits, influence fitness of floral visitors, and respond to anthropogenic change is unclear. A deeper understanding of these phenomena could illuminate the ecological and evolutionary importance of floral microbiomes and their role in the conservation of plant–pollinator interactions.

scholarly journals Quality of anticholinergic burden scales and their impact on clinical outcomes: a systematic review

2020 ◽  
Author(s):  
Angela Lisibach ◽  
Valérie Benelli ◽  
Marco Giacomo Ceppi ◽  
Karin Waldner-Knogler ◽  
Chantal Csajka ◽  
...  
Keyword(s):  
Side Effects ◽  
Clinical Outcomes ◽  
Validation Studies ◽  
Multiple Scales ◽  
Meta Analysis ◽  
Anticholinergic Drug ◽  
Burden Scale ◽  
Newcastle Ottawa Scale ◽  
Anticholinergic Burden

Abstract Purpose Older people are at risk of anticholinergic side effects due to changes affecting drug elimination and higher sensitivity to drug’s side effects. Anticholinergic burden scales (ABS) were developed to quantify the anticholinergic drug burden (ADB). We aim to identify all published ABS, to compare them systematically and to evaluate their associations with clinical outcomes. Methods We conducted a literature search in MEDLINE and EMBASE to identify all published ABS and a Web of Science citation (WoS) analysis to track validation studies implying clinical outcomes. Quality of the ABS was assessed using an adapted AGREE II tool. For the validation studies, we used the Newcastle-Ottawa Scale and the Cochrane tool Rob2.0. The validation studies were categorized into six evidence levels based on the propositions of the Oxford Center for Evidence-Based Medicine with respect to their quality. At least two researchers independently performed screening and quality assessments. Results Out of 1297 records, we identified 19 ABS and 104 validations studies. Despite differences in quality, all ABS were recommended for use. The anticholinergic cognitive burden (ACB) scale and the German anticholinergic burden scale (GABS) achieved the highest percentage in quality. Most ABS are validated, yet validation studies for newer scales are lacking. Only two studies compared eight ABS simultaneously. The four most investigated clinical outcomes delirium, cognition, mortality and falls showed contradicting results. Conclusion There is need for good quality validation studies comparing multiple scales to define the best scale and to conduct a meta-analysis for the assessment of their clinical impact.

Quality of urban patterns: Spatially explicit evidence for multiple scales

2015 ◽  
Vol 142 ◽  
pp. 47-62 ◽  
Author(s):  
U. Wissen Hayek ◽  
D. Efthymiou ◽  
B. Farooq ◽  
T. von Wirth ◽  
M. Teich ◽  
...  
Keyword(s):  
Multiple Scales ◽  
Spatially Explicit ◽  
Urban Patterns
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