Life Sciences Commons^™

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 …

Identification, Life Cycle, And Presence Of Nectria Species Associated With Beech Bark Disease In The Great Smoky Mountains National Park And The Effectiveness Of Nematogonum Ferrugineum As A Biocontrol, Brenda A. Rutherford

Masters Theses

Two species of Nectria, N. galligena Bresadola and N. coccinea var. faginata Lohman, Watson, and Ayers, are associated with beech bark disease (BBD) in North America. In 1993, beech bark disease was discovered in the Great Smoky MOuntains National Park (GSMNP).

Ten sites for permanent plots were selected for incidence of the disease at different elevations in the GSMNP. These plots were rated four times in 1994 and 1995 for the presence of two scale insects, Cryptococcus fagisuga Lindinger and Xylococculus betulae (Pergande) Morrison, and the presence of perithecia of Nectria spp. The beech trees in each plot were also …

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 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 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 …