Fibre deformations induced by different mechanical treatments and their effect on zero-span strength

2012 ◽  
Vol 27 (2) ◽  
pp. 335-342 ◽  
Author(s):  
Xiling Zeng ◽  
Shiyu Fu ◽  
Elias Retulainen ◽  
Sabine Heinemann
Keyword(s):  
Tensile Strength ◽  
Mechanical Treatment ◽  
Kraft Pulp ◽  
Fibre Surface ◽  
Wall Structure ◽  
Fibre Strength ◽  
Different Types ◽  
Chemical Conditions ◽  
Mechanical Devices ◽  
High Consistency

Abstract Fibre deformations have a significant effect on fibre strength and sheet properties. There is little information, however, on the kinds of deformations different types of treatments induce and how they affect the fibre strength. In the present study, first-thinning bleached pine kraft pulp was treated with three mechanical devices: a wing defibrator (high consistency treatment), an E-compactor (high consistency treatment) and a conventional Valley beater (low consistency treatment). The fibre properties were determined with a fibre analyser. The fibre cutting induced by the hydrochloric acid (HCl) treatment (‘cleavage index’) was used for the quantification of the fibre defects. The zero-span tensile strength of dry and wet paper was used to estimate the fibre strength. Each mechanical treatment induced fibre deformations in its own characteristic way. The wing defibrator induced fibre kinks and curl whereas the E-compactor, in addition to fibre cutting, favoured kinks. Low consistency Valley beating straightened the fibres and released fibre deformations. The fibre deformations, especially the number of kinks, correlated well with the wet zero-span tensile strength. The cleavage index had some correlation with the zero-span tensile strength, but the results indicated that the cleavage index may not be directly related to the mechanical defects in fibres but depend more on the chemical conditions on the fibre surface and the wall structure.

Ultrastructural Investigations of the Contractile Filaments of Amoebae

1974 ◽  
Vol 32 ◽  
pp. 188-189
Author(s):  
P.L. Moore
Keyword(s):  
Cytoplasmic Streaming ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Amoeboid Movement ◽  
Different Types ◽  
Chemical Conditions ◽  
Complete Interpretation

Previous freeze fracture results on the intact giant, amoeba Chaos carolinensis indicated the presence of a fibrillar arrangement of filaments within the cytoplasm. A complete interpretation of the three dimensional ultrastructure of these structures, and their possible role in amoeboid movement was not possible, since comparable results could not be obtained with conventional fixation of intact amoebae. Progress in interpreting the freeze fracture images of amoebae required a more thorough understanding of the different types of filaments present in amoebae, and of the ways in which they could be organized while remaining functional.The recent development of a calcium sensitive, demembranated, amoeboid model of Chaos carolinensis has made it possible to achieve a better understanding of such functional arrangements of amoeboid filaments. In these models the motility of demembranated cytoplasm can be controlled in vitro, and the chemical conditions necessary for contractility, and cytoplasmic streaming can be investigated. It is clear from these studies that “fibrils” exist in amoeboid models, and that they are capable of contracting along their length under conditions similar to those which cause contraction in vertebrate muscles.

Influence of small intestine wall changes after electrically welded anastomoses of different types for the anastomotic tensile strength

2018 ◽  
Vol 0 (3) ◽  
pp. 57-62
Author(s):  
S. S. Podpriatov ◽  
S. E. Podpryatov ◽  
S. G. Gichka ◽  
V. G. Getman ◽  
A. V. Makarov ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Small Intestine ◽  
Different Types

scholarly journals The Effect of Water Concentration in Ethyl Alcohol on the Environmentally Assisted Embrittlement of Austempered Ductile Irons

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 94
Author(s):  
Petar Janjatovic ◽  
Olivera Eric Cekic ◽  
Leposava Sidjanin ◽  
Sebastian Balos ◽  
Miroslav Dramicanin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Cast Iron ◽  
Ultimate Tensile Strength ◽  
Ethyl Alcohol ◽  
Water Concentration ◽  
Different Types ◽  
Influence Of Water ◽  
Iron Material ◽  
Proof Strength

Austempered ductile iron (ADI) is an advanced cast iron material that has a broad field of application and, among others, it is used in contact and for conveyance of fluids. However, it is noticed that in contact with some fluids, especially water, ADI material becomes brittle. The most significant decrease is established for the elongation. However, the influence of water and the cause of this phenomenon is still not fully understood. For that reason, in this paper, the influence of different water concentrations in ethyl alcohol on the mechanical properties of ADI materials was studied. The test was performed on two different types of ADI materials in 0.2, 4, 10, and 100 vol.% water concentration environments, and in dry condition. It was found that even the smallest concentration of water (0.2 vol.%) causes formation of the embrittled zone at fracture surface. However, not all mechanical properties were affected equally and not all water concentrations have been critical. The highest deterioration was established in the elongation, followed by the ultimate tensile strength, while the proof strength was affected least.

Preparation and Properties of Optically Transparent Chitin Nanofibers Sheet by Different Simple Mechanical Methods

2013 ◽  
Vol 634-638 ◽  
pp. 2232-2237
Author(s):  
Qin Qin Hu ◽  
Da Gang Li ◽  
Ai Jun Li ◽  
Wen Biao Gu
Keyword(s):  
High Pressure ◽  
Tensile Strength ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Mechanical Treatment ◽  
High Pressure Homogenization ◽  
Flexible Composites ◽  
Mechanical Methods ◽  
Optically Transparent ◽  
Chitin Nanofibers

Chitin nanofibers were prepared from commercially available dried chitin powders by different simple mechanical methods under acid conditions after removal of minerals and proteins. The fibrillated chitin samples were observed by FE-SEM and there was a fine network structure formed by chitin nanofibes with a width of approximately 10-50 nm and high aspect ratio. The mechanical treatment under acid conditions was crucial to facilitate the fibrillation of chitin fibers into nanofibers. The high pressure homogenization in combination with grinding was used to obtain the most transparent chitin nanofibers sheet with a transmittance of 88.5% and tensile strength of 82.34MPa, and the sheet even had a Young’s modulus of 6.17GPa. Thus, chitin nanofibers provide excellent potential as reinforcement of transparent flexible composites to improve the properties of nanocomposites.

Action Mechanism of the Improvement of Printability for Eucalypt Bleached Kraft Pulp Pretreated by Cellulase

2013 ◽  
Vol 779-780 ◽  
pp. 294-301
Author(s):  
Wan You Tang ◽  
Li Chen ◽  
Zheng Jian Zhang
Keyword(s):  
Tensile Strength ◽  
Fiber Length ◽  
Kraft Pulp ◽  
Pulp Fiber ◽  
Fiber Morphology ◽  
Strength Index ◽  
Bleached Kraft Pulp ◽  
Tear Index ◽  
Pulp Sample ◽  
The Mean

Enzymatic refining of eucalypt bleached kraft pulp with the cellulase NOV476 was studied. The effects of this cellulase on the physical properties of pulp, fiber morphology and fiber appearance of the eucalypt bleached kraft pulp in different application conditions were discussed. The results show that, with the increase in the amount of enzyme, tensile strength index, burst index and TEA index of paper are increased and then decreased; elongation and tear index of paper have been declining, Zeeil tensile strength index has been an upward trend. Without beating the pulp sample, gradually increases as the amount of enzyme, the average fiber length and the average fiber width are gradually reduced, while mean kink index substantially constant. Number of vessels in fiber overall reduced tendency reaches a minimum in the amount of enzyme 0.5μ/g, the phenomenon is most obvious. In the same conditions of beating time, gradually increases as the amount of enzyme, the average fiber length is gradually reduced, an average fiber width is gradually increased, the mean kink index reaches a maximum in the amount of enzyme is 0.5μ/g. Number of vessels in fiber overall reduced trend.

EVALUATION OF SPLITTING TENSILE STRENGTH IN PLAIN AND FIBRE-REINFORCED FOAMED MORTAR

2016 ◽  
Vol 78 (5) ◽  
Author(s):  
M. A. Othuman Mydin
Keyword(s):  
Tensile Strength ◽  
Tensile Force ◽  
Splitting Tensile Strength ◽  
Palm Oil Fuel Ash ◽  
Fuel Ash ◽  
Different Types ◽  
Pulverized Fuel ◽  
Pulverized Fuel Ash ◽  
Coconut Fibre ◽  
Oil Fuel

Splitting tensile strength of concrete is normally low compared to compressive and flexural strength. Tensile force was used in the design of structural foamed mortar and to evaluate the shear resistance provided by concrete. This research focuses on the splitting tensile strength of foamed mortar incorporated with 7 different types of fibres used such as wood ash, pulverized fuel ash, silica fume, palm oil fuel ash, polypropylene fibre, coconut fibre and steel fibre. The findings show that the amount of fibres influences the enhancement level of the tensile strength. A high percentage of fibre can create a strong bonding between the particles of the foamed mortar, thus it is able to absorb energy to resist crack formation.

scholarly journals Mechanical Properties of Sigma 1140+ Sic Fibres Prior and after Composite Processing

2000 ◽  
Vol 9 (4) ◽  
pp. 096369350000900 ◽  
Author(s):  
C. Gonzalez ◽  
J. Llorca
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Electron Microscope ◽  
Elastic Modulus ◽  
Weibull Modulus ◽  
Fibre Diameter ◽  
Tensile Tests ◽  
Fibre Strength ◽  
Composite Processing ◽  
Scanning Electron

The effect of processing on the mechanical properties of Sigma 1140+ SiC fibres was studied through tensile tests carried out on pristine Sigma 1140+ SiC fibres and on fibres extracted from a Ti-6A1-4V-matrix composite. The elastic modulus and the tensile strength were computed after measuring carefully the fibre diameter. The characteristic fibre strength was reduced by 20% and the Weibull modulus by half during composite processing. The analysis of the fracture surfaces in the scanning electron microscope showed that the strength-limiting defects were located around the tungsten core in pristine fibres and predominantly at the surface in fibres extracted from the composite panels. These latter defects were nucleated by the mechanical stresses generated on the fibres during the panel consolidation.

scholarly journals Investigation of Atmospheric Moisture during Heat Treatment of Glass Fibres

Fibers ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 27 ◽  
Author(s):  
Peter Jenkins ◽  
Liu Yang ◽  
James Thomason
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Elevated Temperature ◽  
Glass Fibre ◽  
Room Temperature ◽  
Strength Loss ◽  
Fibre Strength ◽  
Atmospheric Moisture ◽  
Glass Fibres ◽  
Alternative Theories

The tensile strength of single water-sized E-glass fibres that were thermally conditioned, either in air or under vacuum, was investigated. The vacuum removed water from the conditioning atmosphere, as well as the fibre surfaces, at room temperature but retained tensile strength of fibres treated in the absence of water were not significantly different from those thermally conditioned in a standard air furnace. The results suggest that water, either in the treatment atmosphere or on the surface of the fibres, is not a significant factor in fundamental glass fibre strength loss at an elevated temperature. It may, therefore, be necessary to consider alternative theories to explain this strength loss.

A comparison of fibre deformations from mill like and laboratory kraft cooking of softwood

2014 ◽  
Vol 29 (2) ◽  
pp. 211-217
Author(s):  
Lennart Salmén ◽  
Joanna Hornatowska
Keyword(s):  
Tensile Strength ◽  
Unsolved Problem ◽  
The Other ◽  
Fibre Strength ◽  
Mechanical Forces ◽  
Lower Strength ◽  
Fibre Properties ◽  
Kraft Cooking ◽  
Pulp Strength ◽  
Fibre Shape

Abstract The fact that industrial pulps have a lower strength than their corresponding laboratory pulps is an unsolved problem affecting in various ways the potential fibre utilisation in different mills. The loss of pulp strength has to a great extent been attributed to changes at the fibre level. In order to clarify in what way changes in fibre properties contribute to the strength losses, cooking experiments were conducted using a laboratory batch digester in which mechanical forces may be introduced. Fibre properties, i.e. fibre structure and fibre strength, of laboratory-made pulps were compared with those of an industrial pulp. It was concluded that two essentially different mechanisms may be identified; one related to the transverse fibre shape, the other to fibre damage. The latter is manifested as lower rewetted zero-span strength which reduces tear resistance and tensile strength of the pulp. The former is a collapse of the fibre, reducing the lumen area and resulting in a pulp with lower water-retaining capacity, given sheets of lower density and a pulp that has to be beaten to a higher degree to reach the desired bonding and the desired tensile strength.

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