scholarly journals Humidity influence on mechanics of paper materials: joint numerical and experimental study on fiber and fiber network scale

Cellulose ◽  
2021 ◽  
Author(s):  
Binbin Lin ◽  
Julia Auernhammer ◽  
Jan-Lukas Schäfer ◽  
Tobias Meckel ◽  
Robert Stark ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Laser Scanning ◽  
Computational Study ◽  
Cellulose Fiber ◽  
Element Model ◽  
Laser Scanning Microscopy ◽  
Fiber Network ◽  
Force Microscopy ◽  
Humidity Level ◽  
Bonding Parameters

AbstractPaper materials are well-known to be hydrophilic unless chemical and mechanical processing treatments are undertaken. The relative humidity impacts the fiber elasticity, the interfiber joint behavior and the failure mechanism. In this work, we present a comprehensive experimental and computational study on mechanical properties of the fiber and the fiber network under humidity influence. The manually extracted cellulose fiber is exposed to different levels of humidity, and then mechanically characterized using atomic force microscopy, which delivers the humidity dependent longitudinal Young’s modulus. We describe the relation and calibrate the data into an exponential function, and the obtained relationship allows calculation of fiber elastic modulus at any humidity level. Moreover, by using confoncal laser scanning microscopy, the coefficient of hygroscopic expansion of the fibers is determined. We further present a finite element model to simulate the deformation and the failure of the fiber network. The model includes the fiber anisotropy and the hygroscopic expansion using the experimentally determined constants, and further considers interfiber behavior and debonding by using a humidity dependent cohesive zone interface model. Simulations on exemplary fiber network samples are performed to demonstrate the influence of different aspects including relative humidity and fiber-fiber bonding parameters on the mechanical features, such as force-elongation curve, strength and extensibility. Finally, we provide computational insights for interfiber bond damage pattern with respect to different humidity level as further outlook.

scholarly journals Influence of Aging on Corrosion Behaviour of the 6061 Cast Aluminium Alloy

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1821
Author(s):  
Ting He ◽  
Wei Shi ◽  
Song Xiang ◽  
Chaowen Huang ◽  
Ronald G. Ballinger
Keyword(s):  
Aluminium Alloy ◽  
Laser Scanning ◽  
Corrosion Behaviour ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Kelvin Probe ◽  
Force Microscopy ◽  
The Matrix ◽  
6061 Aluminium Alloy

The influence of AlFeSi and Mg2Si phases on corrosion behaviour of the cast 6061 aluminium alloy was investigated. Scanning Kelvin probe force microscopy (SKPFM), electron probe microanalysis (EPMA), and in situ observations by confocal laser scanning microscopy (CLSM) were used. It was found that Mg2Si phases were anodic relative to the matrix and dissolved preferentially without significantly affecting corrosion propagation. The AlFeSi phases’ influence on 6061 aluminium alloy local corrosion was greater than that of the Mg2Si phases. The corroded region width reached five times that of the AlFeSi phase, and the accelerating effect was terminated as the AlFeSi dissolved.

scholarly journals Intragenic Antimicrobial Peptide Hs02 Hampers the Proliferation of Single- and Dual-Species Biofilms of P. aeruginosa and S. aureus: A Promising Agent for Mitigation of Biofilm-Associated Infections

2019 ◽  
Vol 20 (14) ◽  
pp. 3604 ◽  
Author(s):  
Lucinda J. Bessa ◽  
Julia R. Manickchand ◽  
Peter Eaton ◽  
José Roberto S. A. Leite ◽  
Guilherme D. Brand ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Laser Scanning ◽  
Multidrug Resistant ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Antibiofilm Activity ◽  
Bacterial Cells ◽  
Generalized Polarization ◽  
Force Microscopy ◽  
Atomic Force

Pseudomonas aeruginosa and Staphylococcus aureus are two major pathogens involved in a large variety of infections. Their co-occurrence in the same site of infection has been frequently reported and is linked to enhanced virulence and difficulty of treatment. Herein, the antimicrobial and antibiofilm activities of an intragenic antimicrobial peptide (IAP), named Hs02, which was uncovered from the human unconventional myosin 1H protein, were investigated against several P. aeruginosa and S. aureus strains, including multidrug-resistant (MDR) isolates. The antibiofilm activity was evaluated on single- and dual-species biofilms of P. aeruginosa and S. aureus. Moreover, the effect of peptide Hs02 on the membrane fluidity of the strains was assessed through Laurdan generalized polarization (GP). Minimum inhibitory concentration (MIC) values of peptide Hs02 ranged from 2 to 16 μg/mL against all strains and MDR isolates. Though Hs02 was not able to hamper biofilm formation by some strains at sub-MIC values, it clearly affected 24 h preformed biofilms, especially by reducing the viability of the bacterial cells within the single- and dual-species biofilms, as shown by confocal laser scanning microscopy (CLSM) and atomic force microscopy (AFM) images. Laurdan GP values showed that Hs02 induces membrane rigidification in both P. aeruginosa and S. aureus. Peptide Hs02 can potentially be a lead for further improvement as an antibiofilm agent.

Fractal Characterisation of Inhomogeneous Rough Surfaces

2011 ◽  
Author(s):  
Daniel J. Burbridge ◽  
Sebastian Howell-Smith ◽  
Mircea S. Teodorescu
Keyword(s):  
Laser Scanning ◽  
Combustion Engine ◽  
Contact Length ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Asperity Contact ◽  
Load Bearing ◽  
Force Microscopy ◽  
Cylinder Liners ◽  
Geometry Analysis

Load bearing conjunctions are never perfectly flat. They are covered by surface features, which may be either unintentional roughness inherent in the manufacturing process or a combination of such roughness with intentionally introduced surface texture. In either case, only a small proportion of load bearing surfaces are in contact and carry load. This depends on the surface topography, material properties and contacting conditions. Simple surface roughness characterisation parameters such as Ra, Rp etc. although commonly used do not give an adequate description, particularly where surfaces are deliberately textured. Furthermore Imaged surface topographies commonly exhibit features below the resolution of the imaging apparatus. We demonstrate the application of a fractal geometry analysis to honed internal combustion engine cylinder liners, imaged by Atomic Force Microscopy and Confocal Laser Scanning Microscopy. This method enables anisotropic surfaces to be characterised by five parameters which can then be used to generate model surfaces whose characteristics follow very closely those of the measured surface. Analysis of the structure function allows the determination of length scales and roughness features relevant at a given contact length. The reconstruction of anisotropic surfaces is demonstrated. Results from modelled contacts between these surfaces reveal the likely asperity contact geometry to be used in modelling contact and friction in these interfaces.

Spectral Analysis of Irregular Roughness Artifacts Measured by Atomic Force Microscopy and Laser Scanning Microscopy

2014 ◽  
Vol 20 (6) ◽  
pp. 1682-1691 ◽  
Author(s):  
Yuhang Chen ◽  
Tingting Luo ◽  
Chengfu Ma ◽  
Wenhao Huang ◽  
Sitian Gao
Keyword(s):  
Atomic Force Microscopy ◽  
Spectral Analysis ◽  
Template Matching ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Scanning Microscopy ◽  
Height Distribution ◽  
Force Microscopy ◽  
Atomic Force ◽  
Autocorrelation Length

AbstractAtomic force microscopy (AFM) and laser scanning microscopy (LSM) measurements on a series of specially designed roughness artifacts were performed and the results characterized by spectral analysis. As demonstrated by comparisons, both AFM and LSM can image the complex structures with high resolution and fidelity. When the surface autocorrelation length increases from 200 to 500 nm, the cumulative power spectral density spectra of the design, AFM and LSM data reach a better agreement with each other. The critical wavelength of AFM characterization is smaller than that of LSM, and the gap between the measured and designed critical wavelengths is reduced with an increase in the surface autocorrelation length. Topography measurements of surfaces with a near zero or negatively skewed height distribution were determined to be accurate. However, obvious discrepancies were found for surfaces with a positive skewness owing to more severe dilations of either the solid tip of the AFM or the laser tip of the LSM. Further surface parameter evaluation and template matching analysis verified that the main distortions in AFM measurements are tip dilations while those in LSM are generally larger and more complex.

Attachment to Minerals and Biofilm Development of Extremely Acidophilic Archaea

2013 ◽  
Vol 825 ◽  
pp. 103-106 ◽  
Author(s):  
Rui Yong Zhang ◽  
Mario Vera ◽  
Sören Bellenberg ◽  
Wolfgang Sand
Keyword(s):  
Laser Scanning ◽  
Preferential Attachment ◽  
Growth Conditions ◽  
Laser Scanning Microscopy ◽  
Epifluorescence Microscopy ◽  
Confocal Laser ◽  
Planktonic Cells ◽  
Force Microscopy ◽  
Morphological Differences ◽  
Biofilm Development

Biofilm development of F. acidiphilum BRGM4 on polycarbonate filters floating on liquid medium and pyrite surfaces were studied by confocal laser scanning microscopy (CLSM) and atomic force microscopy (AFM) combined with epifluorescence microscopy (EFM). Results show that F. acidiphilum biofilms were heterogeneously distributed, and varied among different growth conditions, such as inorganic phosphate (Pi) starvation and glucose supplementation. Biofilm and planktonic cells showed significant morphological differences. Capsular EPS were observed in both biofilm and planktonic cells. Cells showed preferential attachment to the cracks/defects of pyrite surfaces.

scholarly journals Integrated Confocal and Scanning Probe Microscopy for Biomedical Research

2006 ◽  
Vol 6 ◽  
pp. 1609-1618 ◽  
Author(s):  
B.J. Haupt ◽  
A.E. Pelling ◽  
M.A. Horton
Keyword(s):  
Scanning Probe Microscopy ◽  
Laser Scanning ◽  
Fluorescent Imaging ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Pure Material ◽  
Force Microscopy ◽  
Atomic Force ◽  
Ligand Interactions ◽  
Potential Applications

Atomic force microscopy (AFM) continues to be developed, not only in design, but also in application. The new focus of using AFM is changing from pure material to biomedical studies. More frequently, it is being used in combination with other optical imaging methods, such as confocal laser scanning microscopy (CLSM) and fluorescent imaging, to provide a more comprehensive understanding of biological systems. To date, AFM has been used increasingly as a precise micromanipulator, probing and altering the mechanobiological characteristics of living cells and tissues, in order to examine specific, receptor-ligand interactions, material properties, and cell behavior. In this review, we discuss the development of this new hybrid AFM, current research, and potential applications in diagnosis and the detection of disease.

scholarly journals Novel prosthecate bacteria from the candidate phylum Acetothermia revealed by culture-independent genomics and advanced microscopy

2017 ◽  
Author(s):  
Li-Ping Hao ◽  
Simon Jon McIlroy ◽  
Rasmus Hansen Kirkegaard ◽  
Søren Michael Karst ◽  
Warnakulasuriya Eustace Yrosh Fernando ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Metabolic Reconstruction ◽  
Anaerobic Digesters ◽  
Force Microscopy ◽  
Atomic Force ◽  
Culture Independent ◽  
Ecological Importance ◽  
Globally Distributed

AbstractMembers of the candidate phylum Acetothermia are globally distributed and detected in various habitats. However, little is known about their physiology and ecological importance. In this study, an OTU belonging to Acetothermia was detected at high abundance in two full-scale anaerobic digesters. The first closed genome from this phylum was obtained by differential coverage binning of metagenomes and scaffolding with nanopore data. Genome annotation and metabolic reconstruction suggested an anaerobic chemoheterotrophic lifestyle in which the bacterium obtain energy and carbon via fermentation of peptides, amino acids, and simple sugars to acetate, formate, and hydrogen. The morphology was unusual and composed of a central rod-shaped cell with bipolar prosthecae as revealed by fluorescencein situhybridization combined with confocal laser scanning microscopy, Raman microspectroscopy and atomic force microscopy. We hypothesize that these prosthecae allow for increased nutrient uptake by greatly expanding the cell surface area, providing a competitive advantage under nutrient-limited conditions.

Surface Charge and Carbon Contamination on an Electron-Beam-Irradiated Hydroxyapatite Thin Film Investigated by Photoluminescence and Phase Imaging in Atomic Force Microscopy

2014 ◽  
Vol 20 (2) ◽  
pp. 586-595 ◽  
Author(s):  
Radu Hristu ◽  
Denis E. Tranca ◽  
Stefan G. Stanciu ◽  
Maros Gregor ◽  
Tomas Plecenik ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Electron Beam ◽  
Surface Charge ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Scanning Microscopy ◽  
Phase Imaging ◽  
Carbon Contamination ◽  
Force Microscopy ◽  
Atomic Force

AbstractThe surface properties of hydroxyapatite, including electric charge, can influence the biological response, tissue compatibility, and adhesion of biological cells and biomolecules. Results reported here help in understanding this influence by creating charged domains on hydroxyapatite thin films deposited on silicon using electron beam irradiation and investigating their shape, properties, and carbon contamination for different doses of incident injected charge by two methods. Photoluminescence laser scanning microscopy was used to image electrostatic charge trapped at pre-existing and irradiation-induced defects within these domains, while phase imaging in atomic force microscopy was used to image the carbon contamination. Scanning Auger electron spectroscopy and Kelvin probe force microscopy were used as a reference for the atomic force microscopy phase contrast and photoluminescence laser scanning microscopy measurements. Our experiment shows that by combining the two imaging techniques the effects of trapped charge and carbon contamination can be separated. Such separation yields new possibilities for advancing the current understanding of how surface charge influences mediation of cellular and protein interactions in biomaterials.

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