Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 81-86). Also available on the World Wide Web.

This research examined Whole-Tree-Chip cleaning methods applicable to field operations in Pinus taeda L. (Loblolly pine) on the coastal plain of South Carolina. Objectives were: 1) to examine current and potential cleaning methods, and 2) develop and test two cleaning approaches suggested by past research. An open top chip van was modified to: a) determine the dispersion and composition of whole-tree-chip fractions by the installation of sampling buckets and floor pans and b) provide a platform for testing two cleaning systems. System one consisted of anti-clogging screens which pre-screened chips as they were discharged at the mill. It also allowed floor pans to sample the load for fines. System two utilized a radial blade blower which altered chip stream composition during loading by the Whole-Tree-Chipper. Eight trials were conducted over a six month period using a Morbark 22 chipper. Results indicated floor screens could have been more effectively positioned at the chip dump. As installed, and pin they successfully removed 1% of the load in fines chips. The best chip stream treatment involved double deflection: first from a vacuum assisted primary screen located in the van roof, and then from a passive screen located below and behind the first. This design reduced bark and fines by one-third. / Master of Science

This study examined the effects of disk speed, temperature and anvil condition on chip size from sawmill residues of Loblolly pine (<i>Pinus taeda</i> L.). Objectives were: 1) to document the effects of disk speed, temperature and anvil condition on the amount of over thick, oversize, accept, pin and fine chips produced from edgings, 6"x6" cants and trim blocks and 2) to recommend changes in processing sawmill residues to minimize the production of over thick, pin and fine chips. Ten trials were conducted at the Chesapeake Corporation's West Point, Virginia hardwood sawmill using a Fulghum Industries 60-in. (152-cm) diameter, six-knife, vertical disk chipper. Tests were conducted at approximately 80, 70, 60, 50 and 40% of the full disk speed of 707 rpm for the three material types. It was found that decreasing disk speed decreases the amount of pin and fine chips and increases the amount of over thick chips for all material types. The maximum amount of accept and oversize chips was obtained at 50% disk speed. If 50% efficient secondary processing of the over thick chips is achieved, the maximum amount of oversize and accept chips would be produced at 40% disk speed. All frozen and chilled residue types tended to produce less oversize chips and significantly more pins and fines than wood at ambient temperature. A worn anvil caused a significant increase in pins and fines while causing a significant decrease in oversize chips from the cants. Design changes are suggested to reduce the amount of over thick chips produced by vertical disk chippers. / Master of Science

No description available.

Thesis (M.S.)--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references (p. 77-81).

Eutrophication is defined as the ‘over enrichment’ of a water body from nutrients, resulting in uncontrolled growth of primary producers, leading to periods of oxygen depletion from decomposition of the algal organic matter. According to the 2010 Water Infrastructure Needs and Investment (a U.S. Congressional Report), 40% of U.S. water bodies are contaminated with pollutants, including nutrients. Non-point sources of nutrient pollution are a major cause of this reduction in water quality. One way to decrease eutrophication is to manage nutrients found in stormwater runoff, before they reach a receiving water body. Bioretention cells containing an internal water storage zone (IWSZ) have been shown to remove higher amounts of nitrogen than conventional cells (without an IWSZ). The IWSZ contains an organic carbon substrate, usually derived from wood chips submerged in water, which supports the biochemical process of denitrification. Characteristics of wood chips that affect nitrogen removal include carbon content (%), leaching of dissolved organic carbon (DOC), and wood chip size and type. However, there is limited information on how the intermittent hydraulic loading that is associated with these field systems impacts their performance. Accordingly, the overall goal of this research is to improve understanding of the effect that the antecedent dry conditions (ADC) have on the performance of a field scale bioretention cell modified to contain an IWSZ. The nine different types of wood chips used in laboratory and field studies identified in the literature were categorized as hardwood and softwood. Literature showed that total organic carbon (TOC) leached from softwood chips is almost double the TOC measured from the hardwood chips, 138.3 and 70.3 mg/L, respectively. The average observed nitrogen removal for softwood chips was found to be greater than the removal for the average of the hardwood chips (75.2% and 63.0%, respectively). Literature also suggests that larger wood chip size may limit the availability of the carbon for the denitrifying organisms and provides less surface area for the biofilm growth. A field study conducted for this research compared the performance of a modified bioretention system designed to enhance denitrification, addition of an IWSZ, with a conventional system that does not contain an IWSZ. Fourteen storm events were completed from January 2016 to July 2016 by replicating storm events previously completed in the laboratory using hydraulic loading rates (HLR) of 6.9 cm/h, 13.9 cm/h, and 4.1 cm/h. The goal was to have results from storm events with ADCs of two, four, and eight days, with the varying durations of hydraulic loading of two, four, and six hours. Synthetic stormwater, simulating nitrogen levels common in urban runoff, was used as the system’s influent to assist in running a controlled experiment. The resultant ADCs ranged from 0 to 33 days, with the average ADC being 9 days. The fourteen sets of influent samples were averaged to obtain mean influent concentrations for the synthetic stormwater. These values were used when calculating the percent nitrogen removal for the four measured nitrogen species (NOx – N, NH4+– N, organic N, and TN). The field storm events were separated into three groups based on HLR and duration to eliminate the affects of both variables on nitrogen removal for these results, since the focus is the ADC. For the low HLR (4.1 cm/hr), there were four storm events (ADCs of 4 to 33 days), as the ADC increased, greater percentages of ammonium – nitrogen, organic nitrogen, and total nitrogen were removed. For nitrate/nitrite – nitrogen, the percent removal was rather consistent for all four storm events, not significantly increasing or decreasing with changes in the ADC. There were five storm events (ADCs of 0 to 28 days) tested with the median HLR (6.9 cm/hr), nitrogen removal for all four species increased as the ADC increased. The increase was significant (p0.05) for nitrate/nitrite – nitrogen. The third group also contained five storm events (ADCs from 0 to 11 days) that were tested with the highest HLR (13.9 cm/hr). Ammonium – nitrogen, nitrate/nitrite – nitrogen, and total nitrogen all increased with the ADC, and organic nitrogen removal decreased with the increasing ADC. As a result, this research concluded that the difference in HLR affects the nitrogen removal efficiency, but overall increasing the ADC increased nitrogen removal for NOx – N, NH4+ - N, organic N, and TN.

No description available.

The quality of whole-tree wood chips has been the focus of much attention during the past few years because of the increased use of lower grade wood über in pulp production. The need to up-grade the quality has resulted in the use of some form of screening system to separate acceptable wood chips from unwanted material at most pulp mills. In order to upgrade the chip quality, a study was conducted to determine the effect of selected parameters of a separation system with an inclined, vibrating screen on screening efficiency. The parameters studied included screen aperture size and frequency of oscillation. Two screen sizes (3/8 and 1/4 inch apertures) and four different frequencies (1.25, 1.50, 1.75, and 2.00 Hertz) were considered. All other shaker unit parameters were held constant. Statistical analysis revealed that the lowest frequency resulted in the highest screening efficiencies for both the pin chips and fines categories. Screening efficiencies were higher with 3/8 inch screen as opposed to 1/4 inch screen, for all frequencies considered, but at 1.25 Hertz, the screening efficiency of fines was only 6 percent better with 3/8 inch screen. This analysis revealed that the lowest acceleration vectors produced the best screening efficiencies. Velocity and acceleration vectors were directly related to frequency of oscillation since all other parameters were held constant for this study. A Programmer’s Hierarchical Interactive Graphics System (PHIGS) program was developed to graphically simulate the screen motion and to analyze the maximum velocity and acceleration vectors of the upper swing arm (input link). By interactively changing the shaker unit parameters, the screen motion was animated and viewed, with the calculated vectors used in the statistical analysis. / Master of Science

A pile of mixed hardwood whole tree chips was monitored for one year to identify the effects outside storage would have on the fuel potential of the exposed pile. A 20 foot conical pile was built by gravity feed from an overhead conveyor. Moisture content, fiber loss, ash, specific gravity, higher heating value (HHV), temperature, packing density and pH were the variables examined and from these changes, Total Net Heating Value was estimated. Moisture content and packing density showed a significant increase with time. Pile temperature remained below freezing for the first ten weeks of the study then rapidly rose above the ambient air temperature to a maximum of 82 degrees C before falling to near ambient where it remained. After six months,moisture content within the pile stratified into layers reflecting steep moisture content gradients. The outermost layer became saturated, primarily due to rainfall while spontaneous drying reduced the innermost layer's moisture content. The Total Net Heating Value (TNHV) was found to decrease 1.14 percent per month or 13.7 percent a year. Increased moisture content accounts for 88.5 percent of the loss. Lower HHV accounts for 11.5 percent of the loss in TNHV. Storage suggestions and recommendations are included / M.S.

The primary objective of this study was to improve residue chip quality at high production southern pine Sawmills. A general economic analysis suggested that improving sawmill residue chip quality could be beneficial to both pulp and sawmills. Studies were conducted at several sawmills to determine methods of improving residue chip quality. The first study examined the composition of material entering a residue chipper. Trim ends and oversize chips contributed the most pieces, but only 10% of the residue weight. Two-foot trim blocks accounted for the remaining material, 90% by weight. A number of these pieces resulted from slashing entire boards or cutting longer trim lengths into 2-foot pieces to clear them from the mill. Two studies were conducted to examine the possibility of leaving trim in longer lengths to improve piece orientation and stability. Both studies found significant improvements in chip quality, the over-thick chips decreased while the percentage of acceptable chips increased. Chip quality improved with each incremental increase in trim length, but increasing trim length to four feet alone accounted for 50% of the overall improvements. Four-foot trim lengths would generate an additional 4-5 tons of acceptable chips per day for the sawmill. Feed conveyor loading was found to affect chip quality. Highest chip quality was achieved when the feed conveyor was half-full, with two or three pieces entering simultaneously. An overloaded conveyor produced higher percentages of large chips, whereas chipping single pieces increased the percentage of smaller chips. The effect of seasonal temperatures on pin chip and fine production at southern pine and hardwood chip mills was examined as a secondary objective. The pin chip and fine content at the hardwood mills increased as temperatures decreased, but variability in species and inventory obscured the relationship. Southern pine chip mills experienced 4-5% increases in the pin chip and fine content during the winter months. Pin chips and fines increased 1% for every 10°F drop in temperature. / Master of Science