Selective enzyme impregnation of chips to reduce specific refining energy in alkaline peroxide mechanical pulping

Holzforschung ◽  
2009 ◽  
Vol 63 (4) ◽  
Author(s):  
Peter W. Hart ◽  
Darrell M. Waite ◽  
Luc Thibault ◽  
John Tomashek ◽  
Marie-Eve Rousseau ◽  
...  
Keyword(s):  
High Spatial Resolution ◽  
Enzyme Hydrolysis ◽  
Chemical Pretreatment ◽  
Alkaline Peroxide ◽  
Fiber Wall ◽  
Transmission Electron ◽  
Eucalyptus Wood ◽  
Pulp Processing ◽  
Two Stages ◽  
S2 Layer

Abstract Eucalyptus wood chips were impregnated with various blends of fiber modifying enzymes prior to preconditioning refiner chemical-alkaline peroxide mechanical pulp processing. The process includes chemical pretreatment and two stages of refining. The energy consumption was compared at the same Canadian standard freeness level of 350 ml. Some enzyme treatments were found to reduce specific refining energy (SRE) by at least 24%. The enzyme hydrolysis within the cell wall was observed by transmission electron microscopy of impregnated chips with high spatial resolution. The enzyme blends that successfully reduced SRE requirements were found to selectively loosen the bonds between the S1 and S2 layers of the fiber wall. Enzymes which selectively attached the S2 layer did not impart any SRE reduction. All experiments for impregnation and pulp processing were conducted at the Andritz Pilot Plant in Springfield, OH.

Refining Energy Reduction and Pulp Characteristic Modification of Alkaline Peroxide Mechanical Pulp (APMP) Through Enzyme Application

TAPPI Journal ◽  
2009 ◽  
Vol 8 (5) ◽  
pp. 19-25 ◽  
Author(s):  
PETER W. HART ◽  
DARRELL M. WAITE ◽  
LUC THIBAULT, ◽  
JOHN TOMASHEK ◽  
MARIE-EVE ROUSSEAU ◽  
...  
Keyword(s):  
Wood Chip ◽  
The United States ◽  
Enzyme Treatment ◽  
Chemical Application ◽  
Alkaline Peroxide ◽  
Eucalyptus Wood ◽  
Pulp Properties ◽  
Pulp Processing ◽  
Two Stages ◽  
Enzyme Application

Eucalyptus wood chips were subjected to impregnation with various blends of novel fiber modify-ing enzymes before chemical pretreatment and two stages of refining using the preconditioning refiner chemical–alkaline peroxide mechanical pulping (PRC-APMP) process. Wood chip impregnation and pulp processing was con-ducted at a pilot plant in the United States. When compared under constant chemical application and at a constant 350 mL CSF, enzyme treatment reduced specific refining energy by at least 24%. The effect of one versus two stages of impregnation and of enzyme action upon several physical pulp properties was determined.

Formation of Dislocation Channels in Neutron Irradiated Molybdenum

1972 ◽  
Vol 30 ◽  
pp. 672-673
Author(s):  
S. Mahajan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ambient Temperature ◽  
Room Temperature ◽  
Channel Formation ◽  
Early Stages ◽  
Transmission Electron ◽  
Three Stages ◽  
Two Stages ◽  
Polycrystalline Molybdenum

The evolution of dislocation channels in irradiated metals during deformation can be envisaged to occur in three stages: (i) formation of embryonic cluster free regions, (ii) growth of these regions into microscopically observable channels and (iii) termination of their growth due to the accumulation of dislocation damage. The first two stages are particularly intriguing, and we have attempted to follow the early stages of channel formation in polycrystalline molybdenum, irradiated to 5×1019 n. cm−2 (E > 1 Mev) at the reactor ambient temperature (∼ 60°C), using transmission electron microscopy. The irradiated samples were strained, at room temperature, up to the macroscopic yield point.Figure 1 illustrates the early stages of channel formation. The observations suggest that the cluster free regions, such as A, B and C, form in isolated packets, which could subsequently link-up to evolve a channel.

High Spatial Resolution Compositional Analysis at Interfaces

1980 ◽  
Vol 38 ◽  
pp. 356-359
Author(s):  
John B. Vander Sande ◽  
Thomas F. Kelly ◽  
Douglas Imeson
Keyword(s):  
Electron Microscope ◽  
High Spatial Resolution ◽  
Compositional Analysis ◽  
Scanning Transmission Electron Microscope ◽  
Thin Specimen ◽  
X Ray ◽  
Volume Of Interest ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Electron Energy Loss

In the scanning transmission electron microscope (STEM) a fine probe of electrons is scanned across the thin specimen, or the probe is stationarily placed on a volume of interest, and various products of the electron-specimen interaction are then collected and used for image formation or microanalysis. The microanalysis modes usually employed in STEM include, but are not restricted to, energy dispersive X-ray analysis, electron energy loss spectroscopy, and microdiffraction.

In-Situ Study of Ti/TiN Stability under Nitrogen Anneal

1999 ◽  
Vol 564 ◽  
Author(s):  
P. W. DeHaven ◽  
K. P. Rodbell ◽  
L. Gignac
Keyword(s):  
Annealing Temperature ◽  
Time Range ◽  
Second Phase ◽  
Transformation Rate ◽  
Transformation Mechanism ◽  
Second Stage ◽  
Transmission Electron ◽  
Reaction Proceeds ◽  
Two Stages

AbstractThe effectiveness of a TiN capping layer to prevent the conversion of α-titantium to titanium nitride when annealed in a nitrogen ambient has been studied over the temperature range 300–700°C using in-situ high temperature diffraction and transmission electron microscopy. Over the time range of interest (four hours), no evidence of Ti reaction was observed at 300°C. At 450°C. nitrogen was found to diffuse into the Ti to form a Ti(N) solid solution. Above 500°C the titanium is transformed to a second phase: however this reaction follows two different kinetic paths, depending on the annealing temperature. Below 600°C. the reaction proceeds in two stages, with the first stage consisting of Ti(N) formation, and the second stage consisting of the conversion of the Ti(N) with a transformation mechanism characteristic of short range diffusion (grain edge nucleation). Above 600°C, a simple linear transformation rate is observed.

Dynamics of thin precursor film in wetting of nanopatterned surfaces

2021 ◽  
Vol 118 (38) ◽  
pp. e2108074118
Author(s):  
Utkarsh Anand ◽  
Tanmay Ghosh ◽  
Zainul Aabdin ◽  
Siddardha Koneti ◽  
XiuMei Xu ◽  
...  
Keyword(s):  
High Speed ◽  
Liquid Droplet ◽  
Water Film ◽  
Precursor Film ◽  
Intermediate Step ◽  
Dense Array ◽  
Flat Surfaces ◽  
Transmission Electron ◽  
Phase Transmission ◽  
Two Stages

The spreading of a liquid droplet on flat surfaces is a well-understood phenomenon, but little is known about how liquids spread on a rough surface. When the surface roughness is of the nanoscopic length scale, the capillary forces dominate and the liquid droplet spreads by wetting the nanoscale textures that act as capillaries. Here, using a combination of advanced nanofabrication and liquid-phase transmission electron microscopy, we image the wetting of a surface patterned with a dense array of nanopillars of varying heights. Our real-time, high-speed observations reveal that water wets the surface in two stages: 1) an ultrathin precursor water film forms on the surface, and then 2) the capillary action by nanopillars pulls the water, increasing the overall thickness of water film. These direct nanoscale observations capture the previously elusive precursor film, which is a critical intermediate step in wetting of rough surfaces.

Structure and Properties of the Melt-Spun Fe41Ni39P10Si5B5 Alloy Heat Treated at Elevated Temperatures

2010 ◽  
Vol 163 ◽  
pp. 101-105
Author(s):  
Krzysztof Ziewiec ◽  
Krystian Prusik
Keyword(s):  
Glass Transition ◽  
Phase Transformations ◽  
Storage Modulus ◽  
Elevated Temperatures ◽  
Amorphous Structure ◽  
Transmission Electron ◽  
Melt Spun ◽  
Different Temperatures ◽  
Alloy Heat ◽  
Two Stages

The aim of the work was to provide information on structure development and change of properties at elevated temperatures in Fe41Ni39P10Si5B5 amorphous alloy. The alloy was characterized by X-ray diffraction. The changes of properties were characterized with use of dynamic mechanical thermal analysis (DMTA) and the resistivity measurements at elevated temperatures. The microstructure of the melt spun ribbon was investigated with use of transmission electron microscope (TEM) at different stages of phase transformations after heating to different temperatures. The initially amorphous structure undergoes phase transformations due to glass transition and crystallization of the alloy. The appearance of glass transition region results in decrease of storage modulus and in a reversible change of temperature coefficient of resistivity (TCR). The phases are characterized with use of TEM. The crystallization was found to have the two stages. Formation of bcc crystals and Ni12P5 is followed by transformation of the products into fcc crystals and Ni3P. Temporary changes of the storage modulus and elongation of the sample suggest formation of hard phases during crystallization.

Chemical Nano-tomography of Self-assembled Ge-Si:Si(001) Islands from Quantitative High Resolution Transmission Electron Microscopy

2009 ◽  
Vol 1184 ◽  
Author(s):  
Luciano Andrey Montoro ◽  
Marina Leite ◽  
Daniel Biggemann ◽  
Fellipe Grillo Peternella ◽  
Kees Joost Batenburg ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Three Dimensional ◽  
Precise Knowledge ◽  
Transmission Electron ◽  
Self Consistent ◽  
Chemical Distribution

AbstractThe knowledge of composition and strain with high spatial resolution is highly important for the understanding of the chemical and electronic properties of alloyed nanostructures. Several applications require a precise knowledge of both composition and strain, which can only be extracted by self-consistent methodologies. Here, we demonstrate the use of a quantitative high resolution transmission electron microscopy (QHRTEM) technique to obtain two-dimensional (2D) projected chemical maps of epitaxially grown Ge-Si:Si(001) islands, with high spatial resolution, at different crystallographic orientations. By a combination of these data with an iterative simulation, it was possible infer the three-dimensional (3D) chemical arrangement on the strained Ge-Si:Si(001) islands, showing a four-fold chemical distribution which follows the nanocrystal shape/symmetry. This methodology can be applied for a large variety of strained crystalline systems, such as nanowires, epitaxial islands, quantum dots and wells, and partially relaxed heterostructures.

Effects of refining on the fibre structure of kraft pulps as revealed by FE-SEM and TEM: Influence of alkaline degradation

Holzforschung ◽  
2004 ◽  
Vol 58 (3) ◽  
pp. 226-232 ◽  
Author(s):  
U. Molin ◽  
G. Daniel
Keyword(s):  
Electron Microscopy ◽  
Intrinsic Viscosity ◽  
Fibre Length ◽  
Fibre Surface ◽  
Alkali Concentration ◽  
Kraft Pulps ◽  
Transmission Electron ◽  
Pulp Fibres ◽  
Pfi Refining ◽  
S2 Layer

Abstract The aim of the study was to evaluate the effect of refining on the ultrastructure of spruce pulp fibres. Pulps with different molar masses of cellulose (estimated as intrinsic viscosity) were studied after PFI-refining. The molar masses of the polymers were decreased by increases in alkali concentration during pulping. Fibre surface structures were examined using Field Emission Scanning Electron Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM) was used to observe changes in the internal structure of the fibres. Pulps with lower (125 and 329 ml g−1) intrinsic viscosity showed more damaged during refining than pulps with higher (620 and 1120 ml g−1) intrinsic viscosity. Observations showed pulps with lower intrinsic viscosity to have large decreases in fibre length after refining. Fibres with low intrinsic viscosity (i.e., 125 ml g−1) had less primary wall and S1 layer remaining and the external fibrillation and damage of the S2 layer had increased. The S2 wall of fibres with high intrinsic viscosity showed characteristic delamination. Similar delamination was not visible for fibres with low intrinsic viscosity.

Techniques for Investigating Structure and Composition with High Spatial Resolution

1981 ◽  
Vol 8 ◽  
Author(s):  
John B. Vander Sande
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Spatial Resolution ◽  
Scanning Transmission Electron Microscopy ◽  
High Spatial Resolution ◽  
Compositional Analysis ◽  
Atom Probe ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

ABSTRACTThe techniques of scanning transmission electron microscopy and field iron microscopy/atom probe are briefly described. The advantages of these techniques for high spatial resolution compositional analysis are discussed and examples cited.

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