Forest Sciences Commons^™

Mathematical Model Of Paper Discoloration By Ink Particles, Zbigniew W. Slotwinski

Masters Theses

The goal of this experiment is to investigate how changes in the size and number of ink particles will affect the final brightness of the filter pad.

It was assumed that any differences in brightness of the used Millipore filters were due to change in the average particle size, given the same mass of ink solids on each filter. However, such simplified interpretation of image analysis proved to be inadequate to solve this complex problem.

The correlation between the particle area, number of particles, and brightness drop was established using an algorithm based on the particle area and the square …

A Comparison Between Two Phase System And Single Phase System In Stiff Beveled Blade Coating By Measuring The Blade Forces, Ravi Mohan

Masters Theses

The effect of pigment particle interactions in a two-phase system on blade force is investigated. Three coating colors of 0%, 40% , and 55% solids, of the same high shear viscosity and density, were tested for blade force, blade run-in relationship. The Cylindrical Laboratory Coater was used to blade coat the coating on a polyester film. Blade deflection was measured by placing a probe in direct contact with the back side of the blade. A calibration plot between blade force and blade deflection was then used to determine the actual blade forces. A statistical analysis of the data reveals that …

Effect Of Precalendering On Surface And Printing Properties Of Coated Sheets, Hariharan Venkata-Chinnaswamy

Masters Theses

This study focuses on the effect of different types of precalendering on coated woodfree paper for surface and printing properties as well as coat weight distribution and binder migration.

Precalendering enhanced the gloss and reduced the roughness of the coated paper at all coat weights. In the case of post-calendered papers, any differential effect achieved through various types of precalendering was recovered during post calendering. The final porosity values of precalendered and uncalendered sheets were more dependent on the coat weight at the high coat weights (10-18 g/m² ). At low coat weights the type of precalendering influences the …

The Effect Of Ink Jet Coating Rheology On Screening, Burak Aksoy

Masters Theses

Ink jet coating formulations are becoming of increasing importance due to rapid expansion in digital printing. These coatings have very specific ink absorption requirements, which are fulfilled by using polyvinyl alcohol and silica as binder and pigment, respectively. These coatings have unique rheological behavior and often have problems in industry during the filtering process. In this work, an attempt was made to relate filter blocking to the rheological behavior of the coating. A series of coatings were prepared and their rheological properties characterized. The solids content and pigment selection of the coating were altered in order to adjust the coating …

Direct Measurement Of The Water Retention Of Coatings Under Shear, Mohana Sundaram Thiagarajan

Masters Theses

Coating water loss is one of the most critical concerns in coated paper production. The objective of this study was to determine directly the water retention value under dynamic conditions. The effect of shear rate on water transfer was documented for a delaminated clay coating color. The results showed a small change in water transfer at low shear rates, compared to the static condition. But at higher shear rate, the water transfer increased significantly. The water transfer increased with time, reaching an asymptotic limit at 300 seconds. This indicates that at higher retention time, the water transfer rate is reduced …

The Effect Of Drying And Rewetting On Single Fiber Flexibility For Chemical And Mechanical Pulps, Mark E. Dulemba

Masters Theses

Over the years, various attempts have been made to develop methods to measure fiber flexibility. In the course of developing test methods for fiber flexibility, various studies have been performed that measure the flexibilities of different wood pulps.

In this study, never-dried individual thermomechanical pulp (TMP) and bleached kraft fibers were mounted on the tip of a glass tube submerged in water and deflected by water flow. The deflection of the individual fibers was measured using a microscope and image analysis software. The fibers were then dried, rewetted, and the deflection was measured_again. This drying and rewetting cycle was repeated …

The Repulping Of Wet-Strength Paperboard, Angelo N. Melchiorre

Masters Theses

Beverage carrier paperboard containing the polyamide wet-strength resin is one type of fiber that is presently landfilled. In this study, it was repulped at a 15% consistency and a pH of 10 at 150° F. in a z-bar mixer. Hydrogen peroxide (HP), ammonium perswulfate (AP), sodium persulfate (SP) and dimethyldioxirane (DMD) were used during repulping. The HP was added at 1.0%, 2.5% and 5.0%, based on O.D. weight of the fiber. The remaining chemicals were added at the same oxidation equivalent. During repulping, the pulp was screened using a Britt Jar to determine percent yield over time. Samples were taken …

Effect Of Wire Gauge, Web Speed, And Coating Solids On Leveling Of Streaks In Rod Coating, Mukhtar A. Khan

Masters Theses

The behavior of coatings and their study is becoming more important in proportion to additional use of coated paper. Good coating is key to enhance print quality. Blade coating is quite common, but rod coating is coming back for the advantages it has over blade coating. The process of rod coating is simpler and maintenance is easier. Coatings at low solids can be applied with ease and the impurities are washed away by rod rotation. The surface profile of coating is a potential concern, due to streaks in the machine direction. If the coating is immobilized before the streaks heal, …

Influence Of Metal Ions On Brightness Reversion Of Mechanical And Tmp Pulps, Ajay K. Jain

Masters Theses

High-yield mechanical pulps possess high opacity, bulk, compressibility, and excellent printing properties as well. But these pulps are still not suitable for producing high-grade papers because of discoloration. The brightness with age may be due to the presence of lignin, hemicellulose (and even cellulose), resins, metal ions, and additives such as rosin, alum, starch, and other polymers.

This study includes the effects of different metal ions on brightness stability of wood, thermomechanical pulps, chemithermomechanical pulps, and alkaline peroxide mechanical pulps. Also studied were the influences of metal ions on bleached pulps towards brightness loss. The metal ions selected for this …

Strength Properties Of Steam Exploded Laser Printed Papers, Dhamodharan Srinivasan

Masters Theses

The mam objective of this study was to investigate the effect of steam explosion pulping on the strength properties of recycled fibers. The properties considered were zerospan tensile strength, tensile breaking length, tensile stretch, tensile energy absorption, scott bond and pentosan content. This study also examined the important operating parameters that affect the properties. Laser printed waste paper was pulped by the steam explosion process. The experiments were statistically modeled to cover the various process variables. Chemical addition, residence time, pressure, and dispersant level were varied during the steam explosion experiments. Chemical addition was kept at four levels and other …

The Factors Influencing Electrographic Toner Flotation, Udaykumar Ratilal Raval

Masters Theses

Conventional deinking is the process of removing the ink from usable paper fiber. Electrographic toners are hydrophobic in nature because they have negligible negative charge. A study of the effect of fundamental properties leading to electrographic toner flotation in presence of free fibers has not been reported.

Flotation deinking of fused "sharp" toner fraction below 300 micron in the presence of free fibers was performed in the Hallimond tube. Cationic (Dodecyltrimethyl ammonium bromide - DTAB) and anionic (Sodium dodecyl sulfate - SDS) surfactants having similar molecular weights were used at two concentration levels and two pH levels. The effect of …

The Effects Of Fines, Drying Intensity And Recycling On Pulp And Paper Properties, Chiranjiv K. Singh

Masters Theses

The effects of fines level, drying intensity and recycling on pulp and paper properties of bleached softwood kraft were evaluated graphically and statistically.

Fiber fines (100-mesh) were mixed in proportions of 0, 10, 20, 40% with the long fiber fraction. These pulps were tested for fiber length distribution. Handsheets prepared from these pulps were dried at low (air dry) and high (220°F, 4.25 min) drying intensities. These handsheets were recycled and new handsheets were dried at the above drying levels.

Water retention values increased with increasing level of fines for virgin pulp. Recycling resulted in a 20% decrease in water …

The Effect Of Manganese Peroxidase On Peroxide Bleaching Of High Yield Pulps, Cyril Vusani Simelane

Masters Theses

The main objective of this study was to investigate the effect of adding a pretreatment stage in conventional hydrogen peroxide bleaching of high yield pulps. To achieve this, three main variables considered crucial in the effectiveness of manganese peroxidase on the oxidation of lignin substructures, were chosen to evaluate the effect of this enzyme on high yield pulps. The responses to evaluate this effect were brightness, brightness reversion, pulp viscosity, and yield. Other properties included opacity, scattering and absorption coefficients, and the Hunter Lab values.

The pulps were bleached using two sequences Q(MnP), and Q(MnP)QP, to assess the effect of …

The Effect Of Age And Recycling On Paper Quality, Zhuang Wu

Masters Theses

The effects of recycling paper that has undergone aging for different periods on paper and fiber properties like strength, weighted average fiber length, and water retention value were investigated in this study. Old Newspapers (ONP) with different periods of natural aging (between 1 to 10 months) were recycled repeatedly for up to six times. Another goal was the study of aging effects on paper properties using accelerated aging at high temperatures (105±2) °C. Four different aging times (24, 48, 72, and 144 hours) were employed.

The results showed that naturally aged ONP loses little in strength properties up to 7 …

The Effect Of Wet End Operations On Sizing Loss In Alkaline Papers, Suresh B. Cherukuri

Masters Theses

Changes in wet end of alkaline papermaking affect the size development as well as sizing loss. These changes include pH, alkalinity and type of filler used. Precipitated and ground varieties of carbonate fillers and the alkalinity associated with · them are believed to be the causes for the gradual sizing loss in alkaline papers due the accelerated hydrolysis reaction of sizing chemicals at higher alkalinity.

Precipitated and ground calcium carbonate fillers are used as fillers and compared to non carbonate filler such as kaolin clay for their response to size development and sizing loss at lower and higher alkalinity ranges …

The Effects Of Group Selection On The Characteristics And Use Of Cavity Trees And Snags, Mary Lynn Lambert

Masters Theses

I studied the effects of group selection tree harvest on the availability, composition, and use of cavity trees, snags and cavities in the Ozark Mountains of northwestern Arkansas. Sixteen plots dominated by oaks and hickories that were 70-102 years old were surveyed prior to harvest. Tree species, diameter, height and number of visible cavities were recorded. In addition, 192 cavity trees were marked for wildlife observations during the summer and winter. Subsequently, plots were harvested by commercial contractors to either 15 or 19 m²/ha basal area, using either free or structural control thinning methods. A complete survey of …

Reverse Osmosis Treatment Of Deinking Effluents, Lei Zhao

Masters Theses

The application of the reverse osmosis process for treatment of preclarified deinking effluent was studied for its efficiency and capacity to remove the total suspended and dissolved solids. Seven coagulants and flocculents were studied in the pretreatment to determine the best coagulant. Two variables, temperature and coagulant dose, were studied to determine the optimum conditions. For the reverse osmosis treatment, two types of thin film composite membranes, sea water and brackish water were used in the research. A set of orthogonal experiments and regression analyses were conducted to study the effects of pressure, temperature, feed concentration, and feed pH on …

Effects Of Polymers On Pressure Water Retention And Binder Migration Of Aqueous Coatings, Arvind M. Singhal

Masters Theses

The effects of the molecular properties (degree of polymerization and degree of substitution) of water soluble polymers (containing carboxyl and hydroxyl groups on cellulosic backbone) on water retention under pressure and subsequent binder migration of coating colors are documented. It is concluded that no single mechanism can explain either water retention or binder migration. The dominant mechanisms of water penetration under dynamic pressure pulse are different from the mechanisms of water absorption under static pressure.

It is proposed that the molecular properties affect the rate of consolidation of the coating layer and thus greatly affect the water penetration under a …

The Effects Of Repulping Variables On Deinking Of Flexographic Inks, Sylvia Ciampa

Masters Theses

The effects of repulping variables (pH, surfactant concentration, time, and temperature) on deinking paper printed with flexographic ink were studied. A series of alcohol ethoxylate surfactants was evaluated. The one with HLB= 11.8 was selected for the majority of the study.

pH was the variable that presented the greatest effect on repulping and deinking. The brightness after repulping and the final brightness after deinking was significantly higher at pH 5 than at pH 9.

Paper was repulped for 15, 25, and 40 minutes respectively. Highest brightness after repulping and highest gain in brightness by flotation was observed after 15 minutes …

The Interaction Of Coated Paper Surfaces And Water- And Solvent-Based Rotogravure Printing Inks, Tanja M. Gnad

Masters Theses

The print quality of 24 different coating formulations was studied when printing with both water- and solvent-based rotogravure ink. Coating was done on a Cylindrical Laboratory Coater (CLC). The coated paper samples were supercalendered to achieve a smooth surface which is necessary when printing with rotogravure. The supercalendered coated paper samples where tested for optical and surface properties and also printed with water-based and solvent-based ink on a Moser Gravure Proof Press. The print quality of the printed samples was quantified by image analysis. The results showed that fine ground calcium carbonate gave the lowest percent bridging between ink dots, …

Physical And Optical Properties Of Steam Exploded Laser Printed Paper, Arvind Kumar Sharma

Masters Theses

The main objective of this study was to investigate the effects of steam explosion on the optical properties of recycled fibers, i.e., brightness, opacity, scattering and absorption coefficients, and to find out whether explosive discharge caused fiber damage and affected fiber bonding ability.

Laser printed paper was pulped by the steam explosion process. Addition of two different chemicals, residence time, pressure, and dispersant level were varied during the steam explosion experiments. All factors were kept at two levels.

Full factorial design and regression analysis were applied to determine the effect of different factors on steam explosion pulp. The data indicate …

Rheology Of Coating Colors Containing Water-Soluble Polymers And Their Effect On The Runnability Of The Clc Blade Coater, Harish K. Narasimhamurthy

Masters Theses

Four different classes of commercial rheology modifiers (thickeners) e.g., Polyacrylate (PA), Associative Cellulosic Thickener (ACT), Associative Synthetic Thickener (AST) and CMC were used in a simplified coating formulation to study their effects on rheological and viscoelastic properties of the coating colors. An attempt was also made to study their effect on runnability using the Cylindrical Laboratory Coater (CLC). A series of coatings were prepared using number one clay and styrene-butadiene latex. The thickeners were added to these at several levels. The coatings were evaluated for rheological and viscoelastic properties. The coatings were also applied onto paper using the CLC at …

Effect Of Poly Acrylate Addition On Coating Color Rheology, Water Retention And Coating Performance, Shambhu Nath

Masters Theses

Five polyacrylate samples were used to study their effects on coating color rheology, water holding and runnability. The Cylindrical Laboratory Coater was used to apply the coatings and study the runnability of the coating colors. The healing tendencies of the coatings were studied by inducing a scratch under the blade. The higher acid level and degree of crosslinking of the polyacrylate gave higher viscosity and the higher acid level also gave higher water retention. Coating colors containing polyacrylates were less prone to dilatancy at high shear. The addition of polyacrylate reduced the healing of coating colors, but for the same …

Effects Of Alkaline Internal Sizing On Rotogravure Print Quality Using Waterbased Inks, Michael L. Busche

Masters Theses

The effect of alkaline internal sizing in improving paper smoothness and ink gloss in waterbased rotogravure printing was investigated. Papers were internally sized with alkyl ketene dimer (AKD) under alkaline conditions from slack-sized to hard-sized. Papers were printed with waterbased inks on a web gravure press. A major problem with waterbased inks is increased surface roughening of paper and a low ink gloss. Temporal surface roughening was reduced by increased AKD internal sizing with a concomitant significant increase of up to 400% in ink gloss. Surface properties were correlated with print quality. The print quality improved with increased hydrophobicity of …

The Effect Of Viscosity In Beveled Blade Coating, Salih Cebe

Masters Theses

The objective of this study was to investigate the effects of several types of coating viscosity on coat weight development during the beveled blade coating process. In this study, the effects of several types of coating viscosity were experimentally investigated at the applicator roll, before and underneath the blade. Coating color viscosities were changed through two methods. The first method involved changing the temperature of coating color at constant carboxymethylcellulose (CMC) concentration, while the second method consisted of varying the CMC concentration in coating formula at constant coating temperature.

Coating viscosity had an influencing effect both on the amount of …

The Slip Velocity Of Coating Formulations Using The High-Shear Viscometer, Daniel Parker Krieger

Masters Theses

When using a cup and bob viscometer, it has long been recognized that errors in the viscosity measurement can arise from several factors, among them slip. Slip is a phenomenon which occurs when there are slipping layers in the fluid under shear, causing a non-uniform velocity gradient to be generated across the gap of the cup and bob viscometer. A layer of fluid at either the bob or cup wall moves faster than the adjoining layers, causing the slipping effect. This leads to a low viscosity calculation for the fluid.

In this study, experiments with coating formulations were conducted using …

Lichen Communities On White Oaks In East-Central Illinois, Michael R. Thon

Masters Theses

This study was conducted as a survey of epiphytic lichen communities occurring on white oak trees at Walnut Point State Park (Douglas Co.) and Fox Ridge State Park (Coles Co.). Using a system of cover classes to estimate lichen cover, quantitative data on the distribution and abundance of epiphytic lichens was obtained. These data were used to calculate summary statistics of each community including total cover, species richness, and Shannon diversity. A total of ten taxa representing six genera were found. The foliose lichen Physcia millegrana had the highest cover in the open canopy habitats while all other taxa had …

Fountain Solution Ph And Conductivity Changes Caused By Paper Extractables During Offset Printing, Douglas E. Cox

Masters Theses

Economical and environmental issues are causing papermakers to change from the traditional acid papermaking process to neutral and alkaline papermaking processes. Also, offset printers are changing from traditional acid type fountain solutions, with or without alcohol, to: (a) neutral, (b) alkaline, and (c) acid with alcohol substitute type fountain solutions. The interaction between these new papermaking variables and fountain solutions and their effect on printability needs to be investigated.

The pH, conductivity, and contact angle changes of five different offset printing fountain solutions were monitored during offset printing press trials on acid, neutral and alkaline basestocks.

The results indicate that …

Black Oak Savannas And Pin Oak Flatwoods In Iroquois County, Illinois, Kenneth Johnson

Masters Theses

A vegetation survey was undertaken at the Iroquois County Conservation Area and the Hooper Branch Nature Preserve in Iroquois County, Illinois. Dry sand savanna, dry-mesic sand savanna, and Pin Oak flatwoods were the three communities under study at the Iroquois County Conservation Area. Carex pensylvanica had the highest relative frequency of any ground layer species present at both the dry and the dry-mesic sand savannas. In both of these sand savanna communities the dominant overstory tree was Quercus velutina. These two communities differed mainly in the composition of their woody ground layer species. Rubus hispidus obovalis had the highest relative …

A Comparison Of Two Mesic Sand Forests In Mason County, Illinois, David Timothy Coates

Masters Theses

The present study included surveys of a four hectare section of Barkhausen Conservation Area and a two hectare forested section in the Sand Prairie-Scrub Oak Nature Preserve. This study examines the floristic composition and structure of these forests, and some of the ecological parameters that may be responsible for their existence. In this study, the number, size and species of all living and dead standing trees (above 10 cm dbh) were recorded for each quadrat. The relative dominance, relative density, importance value, average diameter, density in broad diameter classes and basal area were then calculated for each species. Nested circular …