Impact of fiber structure on edge-wicking of highly-sized paperboard

TAPPI Journal ◽  
2018 ◽  
Vol 17 (08) ◽  
pp. 437-443
Author(s):  
Lebo Xu ◽  
Jeremy Meyers ◽  
Peter Hart
Keyword(s):  
Fiber Surface ◽  
Manufacturing Processes ◽  
Paper Machine ◽  
Liquid Penetration ◽  
Fiber Structure ◽  
Cut Edge ◽  
Local Fiber

Coffee edge-wicking testing was conducted on two groups of highly-sized paperboard manufactured at two mills with similar manufacturing processes, but with vastly different local fiber sources. Although the Hercules size test (HST) indicated similar internal size levels between the two types of board, the edge-wicking behavior was noticeably different. Analysis of fiber structure revealed that the board with more edge-wicking had fibers with thicker fiber walls, which kept the fiber lumen more open after pressing and drying on a paper machine. It was demonstrated that liquid penetration through voids between fibers in highly-sized paperboard was limited, because the fiber surface was well protected by the presence of sufficient sizing agent. Nevertheless, freshly exposed fiber walls and lumens at the cut edge of the sheet were not protected by sizing material, which facilitated edge-wicking. The correlation between fiber structure and edge-wicking behavior was highlighted in this work to inspire development of novel sizing strategies that protect the freshly cut edge of the sheet from edge-wicking.

Increased capillarity in leg muscle of finches living at altitude

1998 ◽  
Vol 85 (5) ◽  
pp. 1871-1876 ◽  
Author(s):  
Russell T. Hepple ◽  
Peter J. Agey ◽  
Larnelle Hazelwood ◽  
Joseph M. Szewczak ◽  
Richard E. MacMillen ◽  
...  
Keyword(s):  
Sarcomere Length ◽  
Fiber Surface ◽  
Carpodacus Mexicanus ◽  
Fiber Structure ◽  
Capillary Length ◽  
Cross Sectional ◽  
Fiber Number ◽  
Mitochondrial Volume ◽  
Leg Muscle

An increased ratio of muscle capillary to fiber number (capillary/fiber number) at altitude has been found in only a few investigations. The highly aerobic pectoralis muscle of finches living at 4,000-m altitude ( Leucosticte arctoa; A) was recently shown to have a larger capillary/fiber number and greater contribution of tortuosity and branching to total capillary length than sea-level finches ( Carpodacus mexicanus; SL) of the same subfamily (O. Mathieu-Costello, P. J. Agey, L. Wu, J. M. Szewczak, and R. E. MacMillen. Respir. Physiol. 111: 189–199, 1998). To evaluate the role of muscle aerobic capacity on this trait, we examined the less-aerobic leg muscle (deep portion of anterior thigh) in the same birds. We found that, similar to pectoralis, the leg muscle in A finches had a greater capillary/fiber number (1.42 ± 0.06) than that in SL finches (0.77 ± 0.05; P < 0.01), but capillary tortuosity and branching were not different. As also found in pectoralis, the resulting larger capillary/fiber surface in A finches was proportional to a greater mitochondrial volume per micrometer of fiber length compared with that in SL finches. These observations, in conjunction with a trend to a greater (rather than smaller) fiber cross-sectional area in A than in SL finches (A: 484 ± 42, SL: 390 ± 26 μm2, both values at 2.5-μm sarcomere length; P = 0.093), support the notion that chronic hypoxia is also a condition in which capillary-to-fiber structure is organized to match the size of the muscle capillary-to-fiber interface to fiber mitochondrial volume rather than to minimize intercapillary O2diffusion distances.

Variations of fiber structure and performance of ONP delinked pulp after modified-laccase/glutamate treatment

2018 ◽  
Vol 33 (4) ◽  
pp. 618-624 ◽  
Author(s):  
Junjing Dong ◽  
Jinquan Wan ◽  
Yongwen Ma ◽  
Yan Wang
Keyword(s):  
Fiber Quality ◽  
Fiber Surface ◽  
Strength Properties ◽  
Physical Analysis ◽  
Fiber Structure ◽  
Paper Strength ◽  
Amino Groups ◽  
Headspace Gas ◽  
Terminal Amino ◽  
And Performance

Abstract This paper discusses the usage of thiourea dioxide to modify the residual terminal amino groups of amino acid in laccase. The effect of modified-laccase/glutamate treatment on the microstructure and properties of old newspaper deinked pulp was investigated by means of fourier transform infrared spectroscopy and headspace gas chromatography. Results showed that after the modified-laccase/glutamate treatment, the content of carboxyl groups in pulp increased remarkably by 20.8 %. Microscope images showed the fiber filamentation was more obvious, and fibrils content on the fiber surface increased. The fiber quality analyse indicated that fiber coarseness decreased notably but length and width changed a little. The paper physical analysis showed that the paper strength properties had improved remarkably while whiteness decreased slightly.

The Influences of Compression Temperature on the Fiber Structure and Tensile Properties of Hemp Reinforced Polypropylene Composites

2014 ◽  
Vol 1073-1076 ◽  
pp. 62-65
Author(s):  
Xiao Hui Zhang ◽  
Xiao Lu Gong ◽  
Guillaume Montay
Keyword(s):  
Tensile Properties ◽  
Marked Reduction ◽  
Fiber Surface ◽  
Tensile Tests ◽  
Reinforced Composites ◽  
Fiber Structure ◽  
Hemp Fiber ◽  
Polypropylene Composites ◽  
Different Temperatures ◽  
Compression Temperature

In this work, polypropylene composites reinforced by woven hemp fiber were fabricated using compression molding. The effects of compression temperature, ranging from 160 °C to 200 oC, on the tensile properties of the resulted composites were studied. The tensile tests of neat woven hemp fiber heated under different temperatures (160-280 oC) were also performed. The scanning electron microscopy (SEM) was employed to observe the fiber surface. The results showed that the tensile properties of the reinforced composites decreased with the increase of compression temperature, but a rise up to 40.31 MPa at 190 oC occurred. The tensile properties of the woven fibers decreased as the temperature increased, even a marked reduction at 220 oC. The SEM presents the fiber surface indicating the degradation of pectin or lignin on the fiber surface.

Simulation of the Influence of Embedded Inserts on the RTM Filling Behavior Considering Local Fiber Structure

2017 ◽  
Vol 742 ◽  
pp. 681-688 ◽  
Author(s):  
Julian Seuffert ◽  
Luise Kärger ◽  
Frank Henning
Keyword(s):  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Front Propagation ◽  
Mold Filling ◽  
Fiber Structure ◽  
Flow Front ◽  
Fiber Volume ◽  
Two Phase ◽  
Local Flow ◽  
Local Fiber

Resin Transfer Molding (RTM) enables an intrinsic manufacturing of fiber reinforced composite parts containing integrated metallic inserts. The inserts are embedded into the fiber layers in the preforming stage of the process and therefore influence the following mold filling. The fiber structure around the embedded insert is strongly influenced by the insert resulting in high local variations of fiber volume fraction which changes the local permeability. This leads to an inhomogenic flow front and can even result in dry spots of the cured part. To predict the formation of air bubbles, a two-phase mold filling simulation is used under consideration of local fiber volume fraction. Local fiber structure is determined using CT-scans of manufactured parts with different orientations of the insert in relation to the preform and to the filling direction. The mold filling simulations allow the evaluation of different filling strategies and show a strong influence of the insert on the local flow front propagation.

scholarly journals Preparation and characterization of polydimethylsiloxane-based paper transparentizing agent and its application in paper coating

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 277-290
Author(s):  
Haoran Ma ◽  
Yujie Gao ◽  
Longgan Tian
Keyword(s):  
Fiber Surface ◽  
Paper Machine ◽  
Optimal Conditions ◽  
Combined Method ◽  
Base Paper ◽  
Surface Sizing ◽  
Dipping Temperature ◽  
Related Plant ◽  
New Type

A new type of polydimethylsiloxane-based paper transparentizing agent was prepared via a combined method. The performance of the transparentizing agent was investigated systematically by adding and dipping, with use of the surface sizing device of a paper machine. Optimum performance was found at 30% concentration of the transparentizing agent and 30 to 45 °C of dipping temperature. Under the optimal conditions, the transparentizing t agent achieved a rapid penetration in the base paper and filled in the pores of the paper, to be further effectively adsorbed and retained on the fiber surface. The transparency of test paper reached as high as 76±0.97 %, which was 37±1.4% higher than that of the control. However, the addition of transparentizing agent reduced the mechanical strength of paper slightly. The as-prepared transparentizing agent was found to exhibit excellent application stability and biodegradability when applied in the paper machine，When used as plastic film, the transparent paper would lose its strength completely after eight weeks. The resulting transparent paper can be used to develop paper-based film and other related plant based transparent/ translucent paper, which has great potential in replacing plastic products and eliminating white pollution.

Studies on Chick Embryo Thrombocytes

1963 ◽  
Vol 09 (02) ◽  
pp. 291-299 ◽  
Author(s):  
Helge Stalsberg ◽  
Hans Prydz
Keyword(s):  
Chick Embryo ◽  
Bleeding Time ◽  
In Vivo Microscopy ◽  
Cut Edge ◽  
Vessel Lumen ◽  
Cellular Constituent

SummaryThe formation of hemostatic plugs were studied in the chick embryo through in vivo microscopy, in sections of hemostatic plugs and by measurements of primary bleeding time. Thrombocytes were found to be their only cellular constituent. Ability to form adequate hemostatic plugs appeared rather abruptly in embryos of stages 16-17 and coincided with an increase in thrombocyte precursors (stages III and IV).The thrombocytes initially adhere to the cut edge of the vessel. The extension of the hemostatic plug into the vessel lumen is a secondary step in plug development.

Influence of Fiber Surface Energy on Mechanical Properties of Sisal Fiber - Bio Based Epoxy Composites

2019 ◽  
Vol 35 (4) ◽  
pp. 485-496
Author(s):  
S. RAJKUMAR ◽  
◽  
R. JOSEPH BENSINGH ◽  
M. ABDUL KADER ◽  
SANJAY K NAYAK ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Energy ◽  
Fiber Surface ◽  
Epoxy Composites ◽  
Sisal Fiber

Environmental benefits of magnesium hydroxide-based peroxide bleaching of mechanical pulp – mill results

TAPPI Journal ◽  
2013 ◽  
Vol 12 (6) ◽  
pp. 9-15 ◽  
Author(s):  
TOMI HIETANEN ◽  
JUHA TAMPER ◽  
KAJ BACKFOLK
Keyword(s):  
Sodium Hydroxide ◽  
Magnesium Hydroxide ◽  
Oxygen Demand ◽  
Pulp Mill ◽  
Transition Metal Ions ◽  
Environmental Benefits ◽  
Raw Material ◽  
Paper Machine ◽  
High Brightness ◽  
Peroxide Bleaching

The use of a new, technical, high-purity magnesium hydroxide-based peroxide bleaching additive was evaluated in full mill-scale trial runs on two target brightness levels. Trial runs were conducted at a Finnish paper mill using Norwegian spruce (Picea abies) as the raw material in a conventional pressurized groundwood process, which includes a high-consistency peroxide bleaching stage. On high brightness grades, the use of sodium-based additives cause high environmental load from the peroxide bleaching stage. One proposed solution to this is to replace all or part of the sodium hydroxide with a weaker alkali, such as magnesium hydroxide. The replacement of traditional bleaching additives was carried out stepwise, ranging from 0% to 100%. Sodium silicate was dosed in proportion to sodium hydroxide, but with a minimum dose of 0.5% by weight on dry pulp. The environmental effluent load from bleaching of both low and high brightness pulps was significantly reduced. We observed a 35% to 48% reduction in total organic carbon (TOC), 37% to 40% reduction in chemical oxygen demand (COD), and 34% to 60% reduction in biological oxygen demand (BOD7) in the bleaching effluent. At the same time, the target brightness was attained with all replacement ratios. No interference from transition metal ions in the process was observed. The paper quality and paper machine runnability remained good during the trial. These benefits, in addition to the possibility of increasing production capacity, encourage the implementation of the magnesium hydroxide-based bleaching concept.

Microstructure simulation of early paper forming using immersed boundary methods

TAPPI Journal ◽  
2011 ◽  
Vol 11 (11) ◽  
pp. 23-30 ◽  
Author(s):  
ANDREAS MARK ◽  
ERIK SVENNING ◽  
ROBERT RUNDQVIST ◽  
FREDRIK EDELVIK ◽  
ERIK GLATT ◽  
...  
Keyword(s):  
Early Paper ◽  
Contact Model ◽  
Fiber Suspension ◽  
Beam Equation ◽  
Immersed Boundary ◽  
Paper Machine ◽  
Immersed Boundary Methods ◽  
Element Discretization ◽  
Microstructure Simulation ◽  
Boundary Methods

Paper forming is the first step in the paper machine where a fiber suspension leaves the headbox and flows through a forming fabric. Complex physical phenomena occur as the paper forms, during which fibers, fillers, fines, and chemicals added to the suspension interact. Understanding this process is important for the development of improved paper products because the configuration of the fibers during this step greatly influences the final paper quality. Because the effective paper properties depend on the microstructure of the fiber web, a continuum model is inadequate to explain the process and the properties of each fiber need to be accounted for in simulations. This study describes a new framework for microstructure simulation of early paper forming. The simulation framework includes a Navier-Stokes solver and immersed boundary methods to resolve the flow around the fibers. The fibers were modeled with a finite element discretization of the Euler-Bernoulli beam equation in a co-rotational formulation. The contact model is based on a penalty method and includes friction and elastic and inelastic collisions. We validated the fiber model and the contact model against demanding test cases from the literature, with excellent results. The fluid-structure interaction in the model was examined by simulating an elastic beam oscillating in a cross flow. We also simulated early paper formation to demonstrate the potential of the proposed framework.

Optical analysis of ink and other contaminants in process waters

TAPPI Journal ◽  
2012 ◽  
Vol 11 (8) ◽  
pp. 51-58
Author(s):  
ANTTI HAAPALA ◽  
MIKA KÖRKKÖ ◽  
ELISA KOIVURANTA ◽  
JOUKO NIINIMÄKI
Keyword(s):  
Optically Active ◽  
Process Water ◽  
Paper Machine ◽  
Optical Analysis ◽  
Direct Process ◽  
Active Components ◽  
Water Contaminants ◽  
Dependent Measurement ◽  
Measurement Methodology

Analysis methods developed specifically to determine the presence of ink and other optically active components in paper machine white waters or other process effluents are not available. It is generally more interest¬ing to quantify the effect of circulation water contaminants on end products. This study compares optical techniques to quantify the dirt in process water by two methods for test media preparation and measurement: direct process water filtration on a membrane foil and low-grammage sheet formation. The results show that ink content values obtained from various analyses cannot be directly compared because of fundamental issues involving test media preparation and the varied methodologies used to formulate the results, which may be based on different sets of assumptions. The use of brightness, luminosity, and reflectance and the role of scattering measurements as a part of ink content analysis are discussed, along with fine materials retention and measurement media selection. The study concludes with practical tips for case-dependent measurement methodology selection.

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