The physical meaning of Grasselli's morphology parameters and its correlations with several other 2D fracture roughness parameters

Positron annihilation lifetime measurements on polymethylmethacrylate (PMMA) at low temperature were performed. Different discrete fitting procedures have been used to analyze the experimental data. It shows that the extracted parameters depend strongly on the fitting procedure. The physical meaning of the results is discussed. The blob model seems to give the best annihilation parameters.

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Optimization of artificial roughness parameters in a solar air heater duct roughened with hybrid ribs

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2021.116871 ◽

2021 ◽

pp. 116871

Author(s):

Raminder Singh Gill ◽

Vishavjeet Singh Hans ◽

Rupinder Pal Singh

Keyword(s):

Solar Air Heater ◽

Artificial Roughness ◽

Roughness Parameters ◽

Air Heater

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The Influence of Block Morphology Parameters on the Block Microenvironment: A Case Study of Xinjiekou District in Nanjing

2021 7th International Conference on E-Business and Applications ◽

10.1145/3457640.3457673 ◽

2021 ◽

Author(s):

Dengyun Wang

Keyword(s):

Morphology Parameters

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Assessing the Functional Properties of TiZr Nanotubular Structures for Biomedical Applications, through Nano-Scratch Tests and Adhesion Force Maps

Molecules ◽

10.3390/molecules26040900 ◽

2021 ◽

Vol 26 (4) ◽

pp. 900

Author(s):

Maria Vardaki ◽

Aida Pantazi ◽

Ioana Demetrescu ◽

Marius Enachescu

Keyword(s):

Surface Roughness ◽

Functional Properties ◽

Bacterial Adhesion ◽

Biomedical Applications ◽

Adhesion Force ◽

Roughness Parameters ◽

Force Microscopy ◽

Atomic Force ◽

The Mean ◽

Scratch Tests

In this work we present the results of a functional properties assessment via Atomic Force Microscopy (AFM)-based surface morphology, surface roughness, nano-scratch tests and adhesion force maps of TiZr-based nanotubular structures. The nanostructures have been electrochemically prepared in a glycerin + 15 vol.% H2O + 0.2 M NH4F electrolyte. The AFM topography images confirmed the successful preparation of the nanotubular coatings. The Root Mean Square (RMS) and average (Ra) roughness parameters increased after anodizing, while the mean adhesion force value decreased. The prepared nanocoatings exhibited a smaller mean scratch hardness value compared to the un-coated TiZr. However, the mean hardness (H) values of the coatings highlight their potential in having reliable mechanical resistances, which along with the significant increase of the surface roughness parameters, which could help in improving the osseointegration, and also with the important decrease of the mean adhesion force, which could lead to a reduction in bacterial adhesion, are providing the nanostructures with a great potential to be used as a better alternative for Ti implants in dentistry.

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Hamiltonian charges in the asymptotically de Sitter spacetimes

Journal of High Energy Physics ◽

10.1007/jhep05(2021)063 ◽

2021 ◽

Vol 2021 (5) ◽

Author(s):

Maciej Kolanowski ◽

Jerzy Lewandowski

Keyword(s):

Phase Space ◽

Initial Data ◽

Exact Solutions ◽

Gravitational Waves ◽

Physical Meaning ◽

De Sitter ◽

Killing Vectors ◽

Asymptotically Flat ◽

Angular Momenta ◽

The One

Abstract We generalize a notion of ‘conserved’ charges given by Wald and Zoupas to the asymptotically de Sitter spacetimes. Surprisingly, our construction is less ambiguous than the one encountered in the asymptotically flat context. An expansion around exact solutions possessing Killing vectors provides their physical meaning. In particular, we discuss a question of how to define energy and angular momenta of gravitational waves propagating on Kottler and Carter backgrounds. We show that obtained expressions have a correct limit as Λ → 0. We also comment on the relation between this approach and the one based on the canonical phase space of initial data at ℐ+.

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Physical meaning of temperature in superstatistics

EPL (Europhysics Letters) ◽

10.1209/0295-5075/130/30005 ◽

2020 ◽

Vol 130 (3) ◽

pp. 30005

Author(s):

E. Gravanis ◽

E. Akylas ◽

G. Livadiotis

Keyword(s):

Physical Meaning

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Investigation of Side Wall Roughness Effect on Optical Losses in a Multimode Si3N4 Waveguide Formed on a Quartz Substrate

Photonics ◽

10.3390/photonics7040104 ◽

2020 ◽

Vol 7 (4) ◽

pp. 104

Author(s):

Anastasia Yakuhina ◽

Alexey Kadochkin ◽

Vyacheslav Svetukhin ◽

Dmitry Gorelov ◽

Sergey Generalov ◽

...

Keyword(s):

Optical Waveguides ◽

Quartz Substrate ◽

Side Wall ◽

Wall Roughness ◽

Roughness Parameters ◽

Optical Losses ◽

Waveguide Width ◽

Integration Density ◽

Frequency Domain Reflectometry ◽

Multimode Operation

This article presents the results of the study of the influence of the most significant parameters of the side wall roughness of an ultra-thin silicon nitride lightguide layer of multimode integrated optical waveguides with widths of 3 and 8 microns. The choice of the waveguide width was made due to the need to provide multimode operation for telecommunication wavelengths, which is necessary to ensure high integration density. Scattering in waveguide structures was measured by optical frequency domain reflectometry (OFDR) of a backscattering reflectometer. The finite difference time domain method (FDTD) was used to study the effect of roughness parameters on optical losses in fabricated waveguides, the roughness parameters that most strongly affect optical scattering were determined, and methods of its significant reduction were specified. The prospects for implementing such structures on a quartz substrate are justified.

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