Full-field hygro-expansion characterization of single softwood and hardwood pulp fibers

AbstractThe dimensional stability of paper products is a well-known problem, affecting multiple engineering applications. The macroscopic response of paper to moisture variations is governed by complex mechanisms originating in the material at all length-scales down to the fiber-level. Therefore, a recently-developed method, based on Global Digital Height Correlation of surface topographies is here exploited to measure the full-field hygro-expansion of single fibers, i. e. a surface strain tensor map over the full field of view is obtained as function of time. From the strain field, the longitudinal and transverse hygro-expansion and principle strains can be calculated. Long- and intermediate-duration dynamic tests are conducted on softwood and hardwood fibers. A large spread in the softwood fiber’s transverse and longitudinal hygro-expansion coefficient ratio was found, while hardwood fibers behave more consistently. Computing the principle strain ratios reduces this spread, as it takes into account the variations of the deformation direction, which is directly affected by the micro-fibril angle (MFA). Furthermore, long-duration tests allow identification of the half-times at which the fibers equilibrate. Finally, the determined major strain angles for all fibers are consistent with the MFA ranges reported in the literature.

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3D Strain and Elasticity Measurement of Layered Biomaterials by Optical Coherence Elastography based on Digital Volume Correlation and Virtual Fields Method

Applied Sciences ◽

10.3390/app9071349 ◽

2019 ◽

Vol 9 (7) ◽

pp. 1349 ◽

Cited By ~ 3

Author(s):

Fanchao Meng ◽

Xinya Zhang ◽

Jingbo Wang ◽

Chuanwei Li ◽

Jinlong Chen ◽

...

Keyword(s):

Automatic Segmentation ◽

Strain Tensor ◽

Three Dimensional ◽

Biological Tissues ◽

Digital Volume Correlation ◽

Optical Coherence ◽

Virtual Fields Method ◽

Full Field ◽

Elasticity Measurement

The three-dimensional (3D) mechanical property characterization of biological tissues is essential for physiological and pathological studies. A digital volume correlation (DVC) and virtual fields method (VFM) based 3D optical coherence elastography (OCE) method is developed to quantitatively measure the 3D full-field displacements, strains and elastic parameters of layered biomaterials assuming the isotropy and homogeneity of each layer. The integrated noise-insensitive DVC method can obtain the 3D strain tensor with an accuracy of 10%. Automatic segmentation of the layered materials is realized based on the full field strain and strain gradient. With the strain tensor as input, and in combination with the segmented geometry, the Young’s modulus and Poison’s ratio of each layer of a double-layered material and a pork specimen are obtained by the VFM. This study provides a powerful experimental method for the differentiation of various components of heterogeneous biomaterials, and for the measurement of biomechanics.

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A new approach to curvature measures in linear shell theories

Mathematics and Mechanics of Solids ◽

10.1177/1081286520972752 ◽

2020 ◽

pp. 108128652097275

Author(s):

Miroslav Šilhavý

Keyword(s):

Strain Tensor ◽

Middle Surface ◽

Surface Strain ◽

Affine Function ◽

Shear Deformations ◽

Strain Measure ◽

Bending Strain ◽

Curvature Measures ◽

Tensor Formula ◽

Strain Measures

The paper presents a coordinate-free analysis of deformation measures for shells modeled as 2D surfaces. These measures are represented by second-order tensors. As is well-known, two types are needed in general: the surface strain measure (deformations in tangential directions), and the bending strain measure (warping). Our approach first determines the 3D strain tensor E of a shear deformation of a 3D shell-like body and then linearizes E in two smallness parameters: the displacement and the distance of a point from the middle surface. The linearized expression is an affine function of the signed distance from the middle surface: the absolute term is the surface strain measure and the coefficient of the linear term is the bending strain measure. The main result of the paper determines these two tensors explicitly for general shear deformations and for the subcase of Kirchhoff-Love deformations. The derived surface strain measures are the classical ones: Naghdi’s surface strain measure generally and its well-known particular case for the Kirchhoff-Love deformations. With the bending strain measures comes a surprise: they are different from the traditional ones. For shear deformations our analysis provides a new tensor [Formula: see text], which is different from the widely used Naghdi’s bending strain tensor [Formula: see text]. In the particular case of Kirchhoff–Love deformations, the tensor [Formula: see text] reduces to a tensor [Formula: see text] introduced earlier by Anicic and Léger (Formulation bidimensionnelle exacte du modéle de coque 3D de Kirchhoff–Love. C R Acad Sci Paris I 1999; 329: 741–746). Again, [Formula: see text] is different from Koiter’s bending strain tensor [Formula: see text] (frequently used in this context). AMS 2010 classification: 74B99

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Characterization of Liposomes Using Quantitative Phase Microscopy (QPM)

Pharmaceutics ◽

10.3390/pharmaceutics13050590 ◽

2021 ◽

Vol 13 (5) ◽

pp. 590

Author(s):

Jennifer Cauzzo ◽

Nikhil Jayakumar ◽

Balpreet Singh Ahluwalia ◽

Azeem Ahmad ◽

Nataša Škalko-Basnet

Keyword(s):

Rapid Development ◽

Fluorescent Labeling ◽

Label Free ◽

Batch Mode ◽

Full Field ◽

Quantitative Phase ◽

Phase Microscopy ◽

Quantitative Phase Microscopy ◽

Tracking Ability

The rapid development of nanomedicine and drug delivery systems calls for new and effective characterization techniques that can accurately characterize both the properties and the behavior of nanosystems. Standard methods such as dynamic light scattering (DLS) and fluorescent-based assays present challenges in terms of system’s instability, machine sensitivity, and loss of tracking ability, among others. In this study, we explore some of the downsides of batch-mode analyses and fluorescent labeling, while introducing quantitative phase microscopy (QPM) as a label-free complimentary characterization technique. Liposomes were used as a model nanocarrier for their therapeutic relevance and structural versatility. A successful immobilization of liposomes in a non-dried setup allowed for static imaging conditions in an off-axis phase microscope. Image reconstruction was then performed with a phase-shifting algorithm providing high spatial resolution. Our results show the potential of QPM to localize subdiffraction-limited liposomes, estimate their size, and track their integrity over time. Moreover, QPM full-field-of-view images enable the estimation of a single-particle-based size distribution, providing an alternative to the batch mode approach. QPM thus overcomes some of the drawbacks of the conventional methods, serving as a relevant complimentary technique in the characterization of nanosystems.

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Structural and computational investigation of an imine-based propeller-shaped macrocyclic cage

SN Applied Sciences ◽

10.1007/s42452-021-04255-7 ◽

2021 ◽

Vol 3 (2) ◽

Author(s):

Sriram Srinivasa Raghvan ◽

Suresh Madhu ◽

Velmurugan Devadasan ◽

Gunasekaran Krishnasamy

Keyword(s):

Band Gap ◽

Density Functional ◽

Strain Tensor ◽

Strong Interactions ◽

Soft Condensed Matter ◽

Functional Theory ◽

Self Assembling ◽

Phenyl Rings ◽

Crystal Volume

AbstractIn this study, we present the synthesis, spectroscopic and structural characterization of self-assembling gem-dimethyl imine based molecular cage (IMC). Self-assembling macrocycles and cages have well-defined cavities and have extensive functionalities ranging from energy storage, liquid crystals, and catalysts to water splitting photo absorber. IMC has large voids i.e., 25% of the total crystal volume thus could accommodate wide substrates. The synthesized imine-based molecular cages are stabilized by coaxial π bonded networks and long-range periodic van der Waal and non-bonded contacts as observed from the crystal structure. IMC also has typical properties of soft condensed matter materials, hence theoretical prediction of stress and strain tensor along with thermophysical properties were computed on crystal system and were found to be stable. Molecular dynamics revealed IMC is stabilized by, strong interactions between the interstitial phenyl rings. Density functional theory (DFT) based physicochemical properties were evaluated and has band gap of around 2.38ev (520 nm) similar to various photocatalytic band gap materials.

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Single-Shot Full-Field Characterization of Short Pulses by Using Temporal Annealing Modified Gerchberg–Saxton Algorithm

Journal of Lightwave Technology ◽

10.1109/jlt.2017.2695722 ◽

2017 ◽

Vol 35 (13) ◽

pp. 2541-2547 ◽

Cited By ~ 2

Author(s):

Zhi Qiao ◽

Yudong Yao ◽

Xiaochao Wang ◽

Wei Fan ◽

Zunqi Lin

Keyword(s):

Single Shot ◽

Short Pulses ◽

Full Field

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Characterization of Tensile and Compressive Behavior of Microscale Sheet Metals Using a Transparent Micro-Wedge Device

ASME 2011 International Manufacturing Science and Engineering Conference, Volume 1 ◽

10.1115/msec2011-50258 ◽

2011 ◽

Author(s):

James Magargee ◽

Jian Cao ◽

Rui Zhou ◽

Morgan McHugh ◽

Damon Brink ◽

...

Keyword(s):

Mechanical Behavior ◽

Thin Sheet ◽

Thin Sheets ◽

Stainless Steel Sheet ◽

Sheet Metals ◽

Compressive Behavior ◽

Buckling Modes ◽

Full Field ◽

Compressive Loads

The cyclic and compressive mechanical behavior of ultra-thin sheet metals was experimentally investigated. A novel transparent wedge device was designed and fabricated to prevent the buckling of thin sheets under compressive loads, while also allowing full field strain measurements of the specimen using digital imaging methods. Thin brass and stainless steel sheet metal specimens were tested using the micro-wedge device. Experimental results show that the device can be used to delay the onset of early buckling modes of a thin sheet under compression, which is critical in examining the compressive and cyclic mechanical behavior of sheet metals.

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Purification and Characterization of a Novel Subtype A3 Botulinum Neurotoxin

Applied and Environmental Microbiology ◽

10.1128/aem.07967-11 ◽

2012 ◽

Vol 78 (9) ◽

pp. 3108-3113 ◽

Cited By ~ 22

Author(s):

William H. Tepp ◽

Guangyun Lin ◽

Eric A. Johnson

Keyword(s):

Type A ◽

Toxin Production ◽

Mouse Bioassay ◽

Purification Method ◽

Duration Of Action ◽

Content Type ◽

Long Duration ◽

Botulinum Neurotoxins ◽

Subtype A

ABSTRACTBotulinum neurotoxins (BoNTs) produced byClostridium botulinumare of considerable importance due to their being the cause of human and animal botulism, their potential as bioterrorism agents, and their utility as important pharmaceuticals. Type A is prominent due to its high toxicity and long duration of action. Five subtypes of type A BoNT are currently recognized; BoNT/A1, -/A2, and -/A5 have been purified, and their properties have been studied. BoNT/A3 is intriguing because it is not effectively neutralized by polyclonal anti-BoNT/A1 antibodies, and thus, it may potentially replace BoNT/A1 for patients who have become refractive to treatment with BoNT/A1 due to antibody formation or other modes of resistance. Purification of BoNT/A3 has been challenging because of its low levels of production in culture and the need for innovative purification procedures. In this study, modified Mueller-Miller medium was used in place of traditional toxin production medium (TPM) to cultureC. botulinumA3 (CDC strain) and boost toxin production. BoNT/A3 titers were at least 10-fold higher than those produced in TPM. A purification method was developed to obtain greater than 95% pure BoNT/A3. The specific toxicity of BoNT/A3 as determined by mouse bioassay was 5.8 × 10750% lethal doses (LD50)/mg. Neutralization of BoNT/A3 toxicity by a polyclonal anti-BoNT/A1 antibody was approximately 10-fold less than the neutralization of BoNT/A1 toxicity. In addition, differences in symptoms were observed between mice that were injected with BoNT/A3 and those that were injected with BoNT/A1. These results indicate that BoNT/A3 has novel biochemical and pharmacological properties compared to those of other subtype A toxins.

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