PAPER PHYSICS .The effect of newsprint furnish composition and sheet structure on wet pressing efficiency

2012 ◽  
Vol 27 (4) ◽  
pp. 790-797 ◽  
Author(s):  
Collin Hii ◽  
Øyvind W. Gregersen ◽  
Gary Chinga-Carrasco ◽  
Øyvind Eriksen
Keyword(s):  
Electron Microscopy ◽  
Surface Layer ◽  
Peak Pressure ◽  
Side Surface ◽  
Thermomechanical Pulp ◽  
Surface Layers ◽  
Sheet Structure ◽  
Wet Pressing ◽  
Solids Content ◽  
Filler Distribution

Abstract The dewatering ability and wet sheet structure after pressing was studied using a dynamic wet pressing simulator in combination with electron microscopy and image analysis. Deinked pulp (DIP) that contains 5% ash dewaters more easi ly than thermomechanical pulp (TMP) when pressed with single roll pulse. The in-plane moisture flow ( crushing) in DIP samples started at higher peak pressure and higher solids content compared to TMP samples. The TMP sample showed higher springback after wet pressing compared to DIP samples. When both TMP and DIP samples were designed to have a higher amount of small pores at the dewatering side surface layers, the samples with coarser TMP pulp could achieve similar dryness as DIP samples when pressed with higher nip pressure. In addition, the DIP samples with higher number of small pores in the outermost I 0 11m thick surface layer in the dewatering side resulted in lower dryness after pressing with a single roll pulse. The effect of filler distribution in paper zdirection on dryness and sheet structure after wet pressing using an 8 milliseconds roll pulse was also studied. In this study the distribution of filler does not affect the maximum achievable dryness (4 1 %) after wet pressing when the total amount of filler in the sheets remains constant, 1 3 .5%. In addition, the samples with more filler in the dewatering layer dewater more easily and yield the maximum achievable dryness ( 40%) after wet pressing at lower nip pressure (2 . 5 MPa) when compared to samples made from TMP (3 6% at 4.4 MPa) and DIP pulps (40% at 4 . 9 MPa).

PAPER PHYSICS. The web structure in relation to the furnish composition and shoe press pulse profiles during wet pressing

2012 ◽  
Vol 27 (4) ◽  
pp. 798-805 ◽  
Author(s):  
Collin Hii ◽  
Øyvind W. Gregersen ◽  
Gary Chinga-Carrasco ◽  
Øyvind Eriksen ◽  
Kai Toven
Keyword(s):  
Porous Structure ◽  
Peak Pressure ◽  
Pulse Length ◽  
Pressure Profile ◽  
Steam Consumption ◽  
Web Structure ◽  
Wet Pressing ◽  
Solids Content ◽  
In The Beginning ◽  
The Web

Abstract This study shows that wet-pressing TMP and DIP with a shoe press pulse may yield similar afterpress solids, provided that an adequate shoe pulse length with similar pressure profile is applied. A wet web with more porous structure in the sheet dewatering (felt) layer seems to contribute to the increased dewatering during wet pressing. In addition, a shoe press pulse with high peak pressure at the end yields higher solids content after wet-pressing and higher bulk compared to a pulse with a peak pressure in the beginning. The increased dewatering during wet-pressing implies a reduction of steam consumption in the dryer.

The effect of MFC on the pressability and paper properties of TMP and GCC based sheets

2012 ◽  
Vol 27 (2) ◽  
pp. 388-396 ◽  
Author(s):  
Collin Hii ◽  
Øyvind W. Gregersen ◽  
Gary Chinga-Carrasco ◽  
Øyvind Eriksen
Keyword(s):  
Strength Properties ◽  
Microfibrillated Cellulose ◽  
Thermomechanical Pulp ◽  
Paper Properties ◽  
Fibre Network ◽  
Air Resistance ◽  
Wet Pressing ◽  
Solids Content ◽  
Ground Calcium Carbonate ◽  
Scanning Electron

Abstract Different qualities of microfibrillated cellulose (MFC) were blended with thermomechanical pulp (TMP) and ground calcium carbonate (GCC) filler. The addition of MFC reduced the drainage of the pulp suspension but improved strength properties. Wet pressing experiments showed that optimal use of MFC and filler could enhance the strength and optical properties without reducing the solids content after wet pressing. Field-emission scanning electron microscopy (FESEM) revealed that MFC adsorbed onto and contributed to the bonding of the filler particles and fibres. The MFC binds the filler-MFC-fines aggregates to the fibre network and partially filled the pore network. As a result, MFC addition increased the air resistance and internal bonding of the sheet.

Structural analysis of the surface-layer protein of spirillum serpens by high-resolution electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 738-739
Author(s):  
W. H. Wu ◽  
R. M. Glaeser
Keyword(s):  
Electron Microscopy ◽  
Surface Layer ◽  
Structural Analysis ◽  
High Resolution ◽  
Low Dose ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Surface Layer Protein ◽  
Morphological Unit ◽  
Resolution Electron

Spirillum serpens possesses a surface layer protein which exhibits a regular hexagonal packing of the morphological subunits. A morphological model of the structure of the protein has been proposed at a resolution of about 25 Å, in which the morphological unit might be described as having the appearance of a flared-out, hollow cylinder with six ÅspokesÅ at the flared end. In order to understand the detailed association of the macromolecules, it is necessary to do a high resolution structural analysis. Large, single layered arrays of the surface layer protein have been obtained for this purpose by means of extensive heating in high CaCl2, a procedure derived from that of Buckmire and Murray. Low dose, low temperature electron microscopy has been applied to the large arrays.As a first step, the samples were negatively stained with neutralized phosphotungstic acid, and the specimens were imaged at 40,000 magnification by use of a high resolution cold stage on a JE0L 100B. Low dose images were recorded with exposures of 7-9 electrons/Å2. The micrographs obtained (Fig. 1) were examined by use of optical diffraction (Fig. 2) to tell what areas were especially well ordered.

Applications of Photoelectron Microscopy

1976 ◽  
Vol 34 ◽  
pp. 506-507
Author(s):  
William J. Baxter
Keyword(s):  
Electron Microscopy ◽  
Thermal Decomposition ◽  
Chemical Composition ◽  
Ultraviolet Radiation ◽  
Thin Layer ◽  
Edge Effects ◽  
Electron Optics ◽  
Surface Layers ◽  
Crystalline Orientation ◽  
Fluorescent Screen

In this form of electron microscopy, photoelectrons emitted from a metal by ultraviolet radiation are accelerated and imaged onto a fluorescent screen by conventional electron optics. image contrast is determined by spatial variations in the intensity of the photoemission. The dominant source of contrast is due to changes in the photoelectric work function, between surfaces of different crystalline orientation, or different chemical composition. Topographical variations produce a relatively weak contrast due to shadowing and edge effects.Since the photoelectrons originate from the surface layers (e.g. ∼5-10 nm for metals), photoelectron microscopy is surface sensitive. Thus to see the microstructure of a metal the thin layer (∼3 nm) of surface oxide must be removed, either by ion bombardment or by thermal decomposition in the vacuum of the microscope.

Surface reconstructions of (001) cleaved GdBa2Cu3O7-δ

1992 ◽  
Vol 50 (1) ◽  
pp. 106-107
Author(s):  
H.W. Zandbergen ◽  
M.R. McCartney
Keyword(s):  
Electron Microscopy ◽  
Copper Oxide ◽  
Grain Boundaries ◽  
Atomic Structure ◽  
Oxygen Deficiency ◽  
Surface Layers ◽  
Layer Sequence ◽  
Surface Reconstructions ◽  
Good Agreement

Very few electron microscopy papers have been published on the atomic structure of the copper oxide based superconductor surfaces. Zandbergen et al. have reported that the surface of YBa2Cu3O7-δ was such that the terminating layer sequence is bulk-Y-CuO2-BaO-CuO-BaO, whereas the interruption at the grain boundaries is bulk-Y-CuO2-BaO-CuO. Bursill et al. reported that HREM images of the termination at the surface are in good agreement with calculated images with the same layer sequence as observed by Zandbergen et al. but with some oxygen deficiency in the two surface layers. In both studies only one or a few surfaces were studied.

The Tegument and Associated Structures of Fasciola Hepatica

1963 ◽  
Vol s3-104 (68) ◽  
pp. 505-512
Author(s):  
L. T. THREADGOLD
Keyword(s):  
Electron Microscopy ◽  
Surface Layer ◽  
Light Microscopy ◽  
Fasciola Hepatica ◽  
Golgi Bodies ◽  
New Knowledge ◽  
Pinocytotic Vesicles ◽  
The Individual ◽  
And Function ◽  
Internal Level

The cuticle of light microscopy is shown by electron microscopy to be a surface layer of protoplasm which is an extension of areas of nucleated protoplasm lying deep in the parenchyma. The cuticle therefore exists at two levels. The external level is syncytial, consisting of plateaux separated by branching valleys. This level contains apical pinocytotic vesicles, numerous mitochondria, endoplasmic membranes, large basal and other vacuoles, and dense spines. Tube-like evaginations from the base of the external level connect it to the individual areas of flask-shaped protoplasm which compose the internal level. Each of these areas of protoplasm contains a nucleus, great numbers of mitochondria, some vacuoles and diffuse inclusions, and the Golgi bodies. The histochemistry and function of the cuticle is discussed in the light of this new knowledge of cuticular ultrastructure, and a comparison is made between the cuticle of Cestoda and Trematoda.

Electrokinetics, Adsorption and Colloid Study of Simulated Nuclear Waste Glasses Leached in Aqueous Solutions

1984 ◽  
Vol 44 ◽  
Author(s):  
Cheng T. Lee ◽  
D. E. Clark
Keyword(s):  
Surface Layer ◽  
Nuclear Waste ◽  
Glass Surface ◽  
Charged Particles ◽  
Electrostatic Repulsion ◽  
Surface Layers ◽  
Short Term ◽  
Chloride Solutions ◽  
Zeta Potentials ◽  
Glass Surfaces

AbstractZeta potentials of SRL-131-29.8% TOS simulated nuclear waste glasses leached in D.I. water, Al, Ca, Mg, and Zn chloride solutions at 90°C were measured as a function of leaching time. For short term leaching, the adsorption of Ca, Mg, Zn and Al reverses the glass surface potential from negative to positive. Colloids were found to be stable in D.I. water and AICl3 solutions after leaching, presumably due to the electrostatic repulsion between the glass surface and similarly charged particles. Colloids were not found in Mg, Zn or Ca chloride solutions after leaching; instead, a relatively thick metasilicate surface layer was formed on glass surfaces leached in these solutions. The concentration of Si in solution is reduced by the formation of these surface layers.

Stresses in the Surface Layer and Hydrogen Absorption and Diffusion in Cavitation Condition

2014 ◽  
Vol 225 ◽  
pp. 131-138
Author(s):  
Jarosław Chmiel ◽  
Jolanta Baranowska ◽  
Roman Jędrzejewski ◽  
Arkadiusz Rzeczycki
Keyword(s):  
Surface Layer ◽  
Stress State ◽  
Hydrogen Absorption ◽  
Surface Layers ◽  
Fem Modeling ◽  
And Diffusion

Cavitation attack in liquids generated a various states of stresses in surface layers of metals. Differences in stress state effects on hydrogen absorption activated by the cavitation implosion. Results of XRD investigation and FEM modeling shows on inhomogenity of process.

scholarly journals Elemental composition of the surface layers formed on titanium at the cathodic treatment in chitosan-containing aqueous-dimethyl sulfoxide solutions of phosphate-molybdate electrolyte

2021 ◽  
Vol 21 (1) ◽  
pp. 32-48
Author(s):  
Svetlana S. Popova ◽  
◽  
Hussein Ali Hussein ◽  
Lyubov’ N. Olshanskaya ◽  
Sergei V. Arzamastsev ◽  
...  
Keyword(s):  
Surface Layer ◽  
Phosphoric Acid ◽  
Organic Solvent ◽  
Dimethyl Sulfoxide ◽  
Electrolyte Solution ◽  
Aqueous Electrolyte ◽  
Sodium Molybdate ◽  
Volume Ratio ◽  
Surface Layers ◽  
Potentiostatic Mode

It was established that at the cathodic treatment of titanium in aqueous dimethyl sulfoxide solutions of sodium molybdate, containing phosphoric acid, at the potential of the cathodic incorporation of sodium (Ec = −2.6 V) in the potentiostatic mode, the composition formed on the electrode surface layer depended not only on the composition of the solution, but also on the volume ratio of the aqueous electrolyte solution and the organic solvent (dimethyl sulfoxide).

Features of damage and modification of surface layers of Al and its alloys by powerful energy flows in a plasma focus device

2021 ◽  
Vol 9 ◽  
pp. 34-52
Author(s):  
V. N. Pimenov ◽  
◽  
S.A. Maslyaev ◽  
Keyword(s):  
Surface Layer ◽  
Plasma Focus ◽  
Phase State ◽  
Structural Phase ◽  
Pulsed Laser ◽  
Plasma Focus Device ◽  
Deuterium Plasma ◽  
Surface Layers ◽  
Pulsed Laser Radiation ◽  
Structural Phase State

The results of the analysis of damageability and modification of the structural-phase state of the surface layers of aluminum and its alloys by powerful flows of fast high-energy ions and high-temperature plasma in Plasma focus devices, as well as using pulsed laser radiation. Pure Al, an alloy of the Al – Mg – Li system, a duralumin alloy, and a composition of a ceramic coating Al2O3 on an Al substrate are considered. It is shown that in the regime of Al irradiation with a power density of q ≈ 106 – 107 W/cm2 in the nano- and microsecond range of pulse durations, ultrafast crystallization of melted surface layer occurs with the formation of a wavy surface relief and the structural fragments of sub-microcrystalline and nanoscale size. After the action of deuterium plasma flows on a duralumin alloy tube located along the axis of the Plasma focus device a modification of the structural-phase state of the alloy is observed: the initial two-phase state of an αAl-solid solution of copper in aluminum and inclusions of the second phase of CuAl2 became fine-grained and single-phase due to the dissolution of CuAl2 particles in the melt. Irradiation of an alloy of the Al – Mg – Li system containing (wt %) 2 % Li and 5 % Mg at q = 5·106 W/cm2, t = 50 – 100 ns after four pulsed impacts of fast ions and deuterium plasma led to the modification the structural-phase state of the surface layer of the alloy, associated with an increase in the content of magnesium oxide and a decrease in the crystal lattice parameter of the Al-based solid solution. The formation of spherical cavities due to the evaporation of lithium into the internal micropores of the surface layer was also found. The low damage and structural stability of Al2O3 ceramics on an Al substrate under beam-plasma impacts in plasma focus device with a radiation power density q ≤ 108 – 109 W/cm2 in the nano- and microsecond range of pulse duration is noted. At the same time, the Al2O3/Al composition was unstable to pulsed laser radiation in the free-running mode (q = 105 – 106 W/cm2, t = 0.7 ms) and Q-switch mode (q = 107 – 108 W/cm2, t = 80 ns). In both cases the coating peeled off from the substrate.

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