scholarly journals The transverse and longitudinal elastic constants of pulp fibers in paper sheets

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Caterina Czibula ◽  
August Brandberg ◽  
Megan J. Cordill ◽  
Aleksandar Matković ◽  
Oleksandr Glushko ◽  
...  

AbstractCellulose fibers are a major industrial input, but due to their irregular shape and anisotropic material response, accurate material characterization is difficult. Single fiber tensile testing is the most popular way to estimate the material properties of individual fibers. However, such tests can only be performed along the axis of the fiber and are associated with problems of enforcing restraints. Alternative indirect approaches, such as micro-mechanical modeling, can help but yield results that are not fully decoupled from the model assumptions. Here, we compare these methods with nanoindentation as a method to extract elastic material constants of the individual fibers. We show that both the longitudinal and the transverse elastic modulus can be determined, additionally enabling the measurement of fiber properties in-situ inside a sheet of paper such that the entire industrial process history is captured. The obtained longitudinal modulus is comparable to traditional methods for larger indents but with a strongly increased scatter as the size of the indentation is decreased further.

2020 ◽  
Vol 223 (18) ◽  
pp. jeb219980
Author(s):  
Mehrdad Javidi ◽  
Craig P. McGowan ◽  
David C. Lin

ABSTRACTThe force–velocity (F–V) properties of isolated muscles or muscle fibers have been well studied in humans and other animals. However, determining properties of individual muscles in vivo remains a challenge because muscles usually function within a synergistic group. Modeling has been used to estimate the properties of an individual muscle from the experimental measurement of the muscle group properties. While this approach can be valuable, the models and the associated predictions are difficult to validate. In this study, we measured the in situ F–V properties of the maximally activated kangaroo rat plantarflexor group and used two different assumptions and associated models to estimate the properties of the individual plantarflexors. The first model (Mdl1) assumed that the percent contributions of individual muscles to group force and power were based upon the muscles' cross-sectional area and were constant across the different isotonic loads applied to the muscle group. The second model (Mdl2) assumed that the F–V properties of the fibers within each muscle were identical, but because of differences in muscle architecture, the muscles' contributions to the group properties changed with isotonic load. We compared the two model predictions with independent estimates of the muscles' contributions based upon sonomicrometry measurements of muscle length. We found that predictions from Mdl2 were not significantly different from sonomicrometry-based estimates while those from Mdl1 were significantly different. The results of this study show that incorporating appropriate fiber properties and muscle architecture is necessary to parse the individual muscles' contributions to the group F–V properties.


Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3874
Author(s):  
Dominika Veselinyová ◽  
Jana Mašlanková ◽  
Katarina Kalinová ◽  
Helena Mičková ◽  
Mária Mareková ◽  
...  

We are experiencing rapid progress in all types of imaging techniques used in the detection of various numbers and types of mutation. In situ hybridization (ISH) is the primary technique for the discovery of mutation agents, which are presented in a variety of cells. The ability of DNA to complementary bind is one of the main principles in every method used in ISH. From the first use of in situ techniques, scientists paid attention to the improvement of the probe design and detection, to enhance the fluorescent signal intensity and inhibition of cross-hybrid presence. This article discusses the individual types and modifications, and is focused on explaining the principles and limitations of ISH division on different types of probes. The article describes a design of probes for individual types of in situ hybridization (ISH), as well as the gradual combination of several laboratory procedures to achieve the highest possible sensitivity and to prevent undesirable events accompanying hybridization. The article also informs about applications of the methodology, in practice and in research, to detect cell to cell communication and principles of gene silencing, process of oncogenesis, and many other unknown processes taking place in organisms at the DNA/RNA level.


Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2350
Author(s):  
Jia Liu ◽  
Guiyun Tian ◽  
Bin Gao ◽  
Kun Zeng ◽  
Yongbing Xu ◽  
...  

Stress is the crucial factor of ferromagnetic material failure origin. However, the nondestructive test methods to analyze the ferromagnetic material properties’ inhomogeneity on the microscopic scale with stress have not been obtained so far. In this study, magnetic Barkhausen noise (MBN) signals on different silicon steel sheet locations under in situ tensile tests were detected by a high-spatial-resolution magnetic probe. The domain-wall (DW) motion, grain, and grain boundary were detected using a magneto-optical Kerr (MOKE) image. The time characteristic of DW motion and MBN signals on different locations was varied during elastic deformation. Therefore, a time-response histogram is proposed in this work to show different DW motions inside the grain and around the grain boundary under low tensile stress. In order to separate the variation of magnetic properties affected by the grain and grain boundary under low tensile stress corresponding to MBN excitation, time-division was carried out to extract the root-mean-square (RMS), mean, and peak in the optimized time interval. The time-response histogram of MBN evaluated the silicon steel sheet’s inhomogeneous material properties, and provided a theoretical and experimental reference for ferromagnetic material properties under stress.


2011 ◽  
Vol 332-334 ◽  
pp. 489-495 ◽  
Author(s):  
Rong Zhou ◽  
Ming Xia Yang

Regenerated cellulose fiber is the most widely-used and most variety of cellulose fiber. Five categories and ten kinds of fibers such as lyocell fiber, modal fiber, bamboo pulp fiber, sheng-bast fiber, Outlast viscose fiber were chosen as the research object. The strength property and elasticity of fibers in dry and wet state were tested and analysis. The comprehensive performances of fabrics were studied and mechanical properties of the fibers were listed in the order from good to bad by grey clustering analysis. The results show lyocell G100 and lyocell LF have better comprehensive mechanical properties ,while other new regenerated cellulose fibers’ comprehensive mechanical properties are general. Among these fibers modal fiber’s comprehensive mechanical properties are slightly better than sheng-bast fibers’ and bamboo pulp fibers’. Modal fiber, sheng-bast fiber and Bamboo pulp fiber have no significantly poor single parameter and all of them have better comprehensive mechanical properties than various viscose fibers. Outlast viscose in which has been added phase change materials sensitive to temperature by Microcapsule techniques fundamentally keeps similar comprehensive mechanical properties with other regenerated cellulose fibers,but its properties decline slightly .


2021 ◽  
Vol 13 (9) ◽  
pp. 1846
Author(s):  
Vivek Kumar ◽  
Isabel M. Morris ◽  
Santiago A. Lopez ◽  
Branko Glisic

Estimating variations in material properties over space and time is essential for the purposes of structural health monitoring (SHM), mandated inspection, and insurance of civil infrastructure. Properties such as compressive strength evolve over time and are reflective of the overall condition of the aging infrastructure. Concrete structures pose an additional challenge due to the inherent spatial variability of material properties over large length scales. In recent years, nondestructive approaches such as rebound hammer and ultrasonic velocity have been used to determine the in situ material properties of concrete with a focus on the compressive strength. However, these methods require personnel expertise, careful data collection, and high investment. This paper presents a novel approach using ground penetrating radar (GPR) to estimate the variability of in situ material properties over time and space for assessment of concrete bridges. The results show that attributes (or features) of the GPR data such as raw average amplitudes can be used to identify differences in compressive strength across the deck of a concrete bridge. Attributes such as instantaneous amplitudes and intensity of reflected waves are useful in predicting the material properties such as compressive strength, porosity, and density. For compressive strength, one alternative approach of the Maturity Index (MI) was used to estimate the present values and compare with GPR estimated values. The results show that GPR attributes could be successfully used for identifying spatial and temporal variation of concrete properties. Finally, discussions are presented regarding their suitability and limitations for field applications.


2016 ◽  
Vol 150 (2) ◽  
pp. 139-149 ◽  
Author(s):  
Margret Scholz ◽  
Galina Pendinen

The pairing behaviour of the individual chromosome arms of Hordeum vulgare (Hv) with their homoeologous arms of H. bulbosum (Hb) at metaphase I of meiosis in tetraploid Hb × Hv hybrids and the frequencies of recombined Hv chromosome arms in selfed offspring were studied on differentially visualized chromosomes after fluorescent in situ hybridisation. The frequencies of paired Hv-Hb arms in the F2 and F3 hybrids were correlated with the frequencies of recombined Hv chromosomes in progenies. Self-generation of hybrids, the number of Hv and Hb chromosomes, and the number of recombined Hv chromosomes of the hybrids strongly influenced the Hv-Hb pairing frequency in meiosis. Within the offspring of F2 and F3 hybrids both Hv plants and hybrids were detected. In contrast, all progenies of the F4 hybrid were hybrids which exhibited centromere misdivisions. The highest frequencies of homoeologous pairing in hybrids and most recombinants were obtained for the barley chromosome 1HL. Recombinants for 4HL, 5HS, 6HS, and 7HS were rarely found. Meiotic pairing and recombinants involving chromosome 1HS were never observed. The results of this study demonstrate that fertile tetraploid interspecific hybrids with a high intergenomic pairing at meiosis are valuable basic material for introgression breeding in barley.


2018 ◽  
Vol 22 (12) ◽  
pp. 6241-6255 ◽  
Author(s):  
Soumendra N. Bhanja ◽  
Xiaokun Zhang ◽  
Junye Wang

Abstract. Groundwater is one of the most important natural resources for economic development and environmental sustainability. In this study, we estimated groundwater storage in 11 major river basins across Alberta, Canada, using a combination of remote sensing (Gravity Recovery and Climate Experiment, GRACE), in situ surface water data, and land surface modeling estimates (GWSAsat). We applied separate calculations for unconfined and confined aquifers, for the first time, to represent their hydrogeological differences. Storage coefficients for the individual wells were incorporated to compute the monthly in situ groundwater storage (GWSAobs). The GWSAsat values from the two satellite-based products were compared with GWSAobs estimates. The estimates of GWSAsat were in good agreement with the GWSAobs in terms of pattern and magnitude (e.g., RMSE ranged from 2 to 14 cm). While comparing GWSAsat with GWSAobs, most of the statistical analyses provide mixed responses; however the Hodrick–Prescott trend analysis clearly showed a better performance of the GRACE-mascon estimate. The results showed trends of GWSAobs depletion in 5 of the 11 basins. Our results indicate that precipitation played an important role in influencing the GWSAobs variation in 4 of the 11 basins studied. A combination of rainfall and snowmelt positively influences the GWSAobs in six basins. Water budget analysis showed an availability of comparatively lower terrestrial water in 9 of the 11 basins in the study period. Historical groundwater recharge estimates indicate a reduction of groundwater recharge in eight basins during 1960–2009. The output of this study could be used to develop sustainable water withdrawal strategies in Alberta, Canada.


CORROSION ◽  
10.5006/2581 ◽  
2017 ◽  
Vol 74 (3) ◽  
pp. 312-325 ◽  
Author(s):  
Cheng Man ◽  
Chaofang Dong ◽  
Kui Xiao ◽  
Qiang Yu ◽  
Xiaogang Li

In situ atomic force microscopy, scanning Kelvin probe force microscopy, and potential pulse technology were used to study the pitting behavior induced by inclusions in AM355 martensitic stainless steel. The MnS-(Cr, Mn, Al)O duplex inclusion exhibited the highest sensitivity to the pitting corrosion with respect to the individual MnS and (Cr, Mn, Al)O inclusions. When exposed to a solution containing Cl−, the selective dissolution occurred on the sulfide segment of the duplex inclusion, leading to trenching along the oxide part. The dissolution mechanism of MnS segment in the duplex inclusion is similar to the individual MnS inclusion. The Cr depletion in the boundary layer at the inclusion/metal interface promoted the transition from metastable to stable pitting corrosion in the duplex inclusion.


2016 ◽  
Vol 37 (4Supl1) ◽  
pp. 2589
Author(s):  
Marjorrie Augusto de Souza ◽  
Edenio Detmann ◽  
Gabriel Cipriano Rocha ◽  
Marcia De Oliveira Franco ◽  
Erick Darlisson Batista ◽  
...  

The objective of this collaborative study was to evaluate the indigestible neutral detergent fiber (iNDF) and indigestible acid detergent fiber (iADF) content in feeds in six laboratories from institutions linked to the National Institute of Science and Technology in Animal Science (INCT-CA). Six feeds were evaluated: signal grass hay, sugarcane, corn silage, soybean meal, corn and citrus pulp. Estimated levels of iNDF and iADF proved to be dependent on the laboratory in which the analysis was performed. It was found that differences between laboratories ranged from 2.40 percentage points for soybean meal to 8.05 percentage points for sugarcane for iNDF analysis and from 1.79 percentage points for corn to 10.06 percentage points for hay for iADF analysis. It was observed that the individual evaluation of each material, the total random variation of the results between laboratories ranged from 88.75 to 96.77% and 88.75 to 98.40% for iNDF and iADF analysis, respectively. The iNDF and iADF levels are dependent on the interaction effect between the evaluated material and laboratory and have low reproducibility; this may be a consequence of the differences between the methods practiced by each laboratory, demonstrating lack of standardization of procedures used by the laboratories.


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