8,441 research outputs found
Substituting Wood with Nonwood Fibers in Papermaking: A Win-Win Solution for Bangladesh
Bangladesh is facing an acute shortage of fibrous raw materials for the production of pulp and paper. On the other hand, the demand for paper and paper products is increasing day by day. This study reviews the availability and suitability of nonwood raw materials for pulp production in Bangladesh. It shows that Bangladesh has a huge amount of unused jute fiber, which is highly suitable for papermaking in Bangladesh. Other agricultural wastes like rice straw, dhaincha, golpata fronds, cotton stalks, corn stalks, and kash are also available and may be used for some pulp production. Given the different properties of these different nonwood fibers, jute pulp can be used as a reinforcing agent with other nonwood pulps for the production of high quality paper in Bangladesh.Bangladesh, natural fibers, jute, paper making, pulp
Papermaking properties of various pulps used for printing paper production
Papermaking properties of recycled pulp obtained from office paper, thermomechanical and chemithermomechanical pulp were investigated. The optimal refining parameters of recycled pulp and chemithermomechanical pulp such as refining time, rotational disk speed and refiner disk gap, allowing to increase their papermaking properties, were determined. It was found that recycled pulp exhibits the greatest efficiency (among the pulps under investigation) of chemical pulps replacing in the furnish composition of offset printing paper
Increasing the Hardwood Content on the Furnish by Separate Refining
Introduction
It is an old papermaker\u27s adage that paper is made in the beater. This means that the performance and the physical properties of the paper are determined by the type and the extent of the mechanical action to which the fibers are subjected before they are joined to form paper. The terms used to describe the function of refining; free beaten, wet beaten, et al are all traditionally vague, by reason of the complicated structure of the fibers and the even more complicated changes these fibers undergo during the refining process
The Strength Effects of Saturating Paper Containing Synthetic Fiber
One of the most important objectives in the papermaking process is to produce paper with good strength properties. Some specialty paper grades need strength properties which exceed those attainable when only wood fiber is present in the final product. To achieve the additional strength, various additives and fibers can be added to the furnish, or supplementary processes can be performed on the paper. The objective to this thesis was to determine the strength effects of saturating paper containing nylon stock, and to attempt to correlate the strength relationship between the two strength enhancing parameters.
To observe the effects of nylon fiber properties, standard paper samples were produced with three different levels of nylon addition: 0, 15, and 30%. The amount of latex added to the sheets by the saturation process was also varied, to determine the latex bonding effects on strength.
The results of the experimentation showed that both the tear strength and the stretching ability of paper increased when nylon was added to the furnish. The tensile and burst strength of the paper was found to decrease with nylon addition, however. The nylon addition was also found to significantly decrease sheet formation, which affected testing results. The improved bonding created by the saturation process was found to increase all the strength properties tested, with burst strength showing the largest improvements. Before implementing either procedure, a careful cost versus property improvement analysis must be completed in order to determine if their use would truly be beneficial
Office paper recyclability: fibrous characteristics
Recyclability is the ability of a material to reacquire the same properties it had originally. The aim of this work was to verify the recyclability of three printing and writing papers, from the characteristics of their fibers after two recycles. Three ECF bleached kraft eucalyptus commercial bond papers from Argentina and Brazil were studied (A, B, C). The papers were repulped and refined using different levels and intensities of energy (1st recycle). Laboratory sheets were produced, and they were repulped and refined again (2nd recycle). The microscopic characteristics of repulped papers were obtained by automatic equipment based on image analysis. Differences found in the behavior of the different samples can be explained by fiber parameters. The fiber length was significantly different in the three papers (A > B > C) and globally decreased in the second recycle (about 6%). Sample A had the highest initial fiber length and length/width, but it largely decreased with refining conditions in the 1st recycle (length fall 12%, generating fines by cutting), whereas it fall 9% between the 1st and 2nd recycles, and nothing with refining conditions in the 2nd recycle. Sample B fall by 5% with refining conditions in the 1st recycle, and 9% between the 1st and the 2nd recycle, but suffered few alteration in the second recycle. Fiber length of sample C was unaffected by refining conditions and only decreased 9% between the 1st and 2nd recycles. In all cases, the generated fines increased lightly with refining in the first recycle, but were two-fold higher in the second recycle than in the first one. The fiber coarseness of the 3 samples was similar in the first recycle, but decreases significantly in the 2nd recycleFil: Benitez, Julieta Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Cs.exactas Químicas y Naturales. Instituto de Materiales de Misiones; ArgentinaFil: Koga, Mariza E. T.. Instituto de Pesquisas Tecnologicas de Sao Paulo; BrasilFil: Otero D'Almeida, Maria L.. Instituto de Pesquisas Tecnologicas de Sao Paulo; BrasilFil: Felissia, Fernando Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Cs.exactas Químicas y Naturales. Instituto de Materiales de Misiones; ArgentinaFil: Park, Song W.. Universidade de Sao Paulo; BrasilFil: Area, Maria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Cs.exactas Químicas y Naturales. Instituto de Materiales de Misiones; Argentin
The Influence of Beating of Pulp on Fiber Length and Fiber Length Distribution
1. Introduction
Recent studies and researchers assume that certain relationships exist between different properties of pulp - such as between bulk, tearing resistance, bursting strength, tensile strength, freeness, and fiber length index. It has been found furthermore that such relations are different for different types of pulp and that some may even vary from pulp to pulp of the same type
The Use of Demolition Wood in Papermaking
The reason for this study came from three factors affecting the paper industry as well as society as a whole. These factors are decreasing landfill space, increasing tipping fees, and increasing demands for alternative fiber sources. In the United States, approximately 9.8 million tons of demolition wood waste is landfilled per year. Increasing governmental regulations which require greater amounts of secondary fiber to be used in papermaking are forcing the industry to consider alternative fiber options. The seven steps in the procedure include: rough wood, wood chips, kraft pulping, fiber refining, screening, handsheets, and testing. The four types of wood involved are a 50 year old house wood, a 100 year old barn wood, a kiln-dried wood, and a red pine green wood. All wood types are pine. The strength test (tensile, burst, tear) revealed that demolition wood fiber is strong enough to be considered as a secondary fiber source. The average value obtained for tear from the demolition wood is 13.7 (mN m2/g). The average values for burst and tensile are 20.3 psi and 4.18 km, respectively. In fact, the values obtained from the old wood are comparable to those obtained by Kleppe for a green wood pine(4). Drawbacks to its use include containment removal, probable bleaching limitations, obtaining the wood, and labor/energy requirements. The resource may best be utilized by having a demolition company deliver the wood, pulp, screen, and refine the wood separately, and have the fibers metered in at know quantities at the blend chest within the paper mill. Ultimately the use of this source becomes a function of society\u27s focus on the green movement and regulations imposed on the industry by the government
Path planning algorithm for a car like robot based on MILP method
This project is presents an algorithm for path planning optimal routes mobile robot
“like a car” to a target in unknown environment. The proposed algorithm allows a
mobile robot to navigate through static obstacles and finding the path in order to
reach the target without collision. This algorithm provides the robot the possibility to
move from the initial position to the final position (target). The proposed path
finding strategy is to use mathematical programming techniques to find the optimal
path between to state for mobile robot designed in unknown environment with
stationary obstacles. Formulation of the basic problems is to have the vehicle moved
from the initial dynamic state to a state without colliding with each other, while at
the same time avoiding other stationary obstacles. It is shown that this problem can
be rewritten as a linear program with mixed integer / linear constraints that account
for the collision avoidance. This approach is that the path optimization can be easily
solved using the CPLEX optimization software with AMPL interface / MATLAB.
The final phases are the design and build coalitions of linear programs and binary
constraints to avoid collision with obstacles by Integer Mixed Linear Program
(MILP). The findings of this research have shown that the MILP method can be used
in the path planning problem in terms of finding a safe and shortest path. This has
been combined with collision avoidance constraints to form a mixed integer linear
program, which can be solved by a commercial software package
Influence of hemicelluloses content on the paper quality produced with Eucalyptus globulus fibres
The raw-material composition and the cooking conditions determine the pulp composition and this affect the behaviour of the pulp in the beating process and the papermaking potential. However, at industrial scale the variability of the pulp composition, for a given raw material and a given process, is relatively low and usually it is difficult to quantify the impacts of pulp composition on beating and papermaking.
In the present study E. globulus bleached pulps were produced under different cooking conditions by the kraft process in order to obtain pulps with significant different hemicelluloses content (19% versus 14.5%). The behaviour of the pulps in beating and the papermaking potential were investigated under two beating intensities in the PFI mill and at four beating times. The pulp suspensions were characterised in terms of drainability, fibre morphology, wet fibre flexibility and relative bonded area. The paper produced was evaluated in terms of structural, superficial, mechanical and optical properties. The results showed the clear effect of the hemicelluloses content on the beating rate as well as on the paper properties
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