Milled Pine Research Articles

Shear rate dependency on flowing granular biomass material

The commercialization of bioenergy has been significantly limited by various material handling issues due to the poor flowability of granular biomass materials. Addressing these issues demands a fundamental understanding of flow physics and robust models to predict the multi-regime flow behavior of biomass particles. In this study, we investigated the multi-regime flow behavior of loblolly pine chips, a widely used bioenergy feedstock, through combined experiments and simulations. A quasi-static hypoplastic model and a cross-regime Drucker–Prager (DP)-μ(I) model were utilized and validated against inclined plane flow experiments to understand the quasi-static and dense flow behavior of milled pine chips. The results show that along the inclined plane, loblolly pine chips mainly present in heap flow (varying thickness along the plane), and in plane flow (iso-thickness along the plane) only when the inclination closes to the material’s critical state internal friction angle. The results also show that the multi-regime DP-μ(I) model predicts a completely different velocity profile from the hypoplastic model. DP-μ(I) model can capture the flow behavior of pine chips in both flow regimes well but at the cost of extra parameter determination, and the shear-rate dependent rheology model can successfully capture the flow of elongated high-frictional particles. These findings advance the scientific understanding of the multi-regime flow behavior of granular biomass materials and shed light on formulating novel constitutive models to assist granular biomass handling in the bioenergy industry.

The role of flexural particles in the shear flow of pine residue biomass: An experiment-informed DEM simulation study

An experiment-informed discrete particle simulation study was performed to investigate the role of flexural particles in the shear flow of milled pine residues. Physical pine anatomical fraction samples were tested in an FT4 powder rheometer. A chip model for bark/stem chips and a fiber model for needles were proposed for DEM. The FT4 simulations show mixed fibers/chips require higher force and torque to drive shear flow than pure chips or fibers. The mass fraction and flexibility of fibers reveal nonlinear inter-dependency on impacting the shear flow of mixed fibers/chips. Polydisperse fibers well match the needle-rich samples on the flow attributes, while polydisperse mixed fibers/chips agree reasonably with the bark/stem-rich samples. The DEM study indicates that the flowability of pine residue biomass is determined collectively by various material attributes of the anatomical fractions, which must be considered when developing preprocessing methods for conversion-ready biomass with adequate material handling performance.

Hopper discharge flow dynamics of milled pine and prediction of process upsets using the discrete element method

Hopper discharge flow dynamics of milled pine and prediction of process upsets using the discrete element method

A set of hysteretic nonlinear contact models for DEM: Theory, formulation, and application for lignocellulosic biomass

A monosphere discrete element method (DEM) model is introduced for elucidating the bulk mechanical behavior of granular biomass. This model considers each sphere as a representative elementary volume in bulk particles and is highly scalable in computation. To compensate for the simplification of particle shapes, we propose a set of hysteretic nonlinear contact models for approximating the bulk strain-hardening phenomena of granular biomass in handling and storage conditions. These contact models comprise of simple polynomial and/or exponential functions to allow for easy calibration. To ensure numerical stability, we have derived unconditionally stabilized viscous damping force models. The resultant DEM model is implemented in LIGGGHTS-INL and applied to simulate an axial compressibility test for milled pine chips. Results show that the DEM model can reproduce the bulk stress–strain profiles of the physical samples and that the predicted bulk compressibility and constrained modulus under repeated compression agree reasonably with the experimental data.

Investigation of Usage of Milled Pine Cone in Brake Pads

Automotive brake pads are polymer composites containing polymer matrix and various fibers and obtained by mixing and pressing different powder materials. Each material added to the content has one or more tasks. Therefore, the properties and quantities of the materials added to the content are very important in terms of braking performance. In this study, the use of milled pinus brutia cone and pinus nigra cone from the pine cone family in the automotive brake pad was investigated experi-mentally. First of all, cones are ground and powdered. The milled 10% pinus brutia cone and 10% pinus nigra cone were added to the pad com-ponent. The performance tests of the pads were carried out on pin on disk type test device. Friction coefficient, wear, density and hardness tests of the pads were done. The test results have been shown to affect the brak-ing performance of milled pine cone.

Storage Procedures Affect pH, Electrical Conductivity, and Nutrient Concentrations of Pour-through Leachate from Pine Bark and Peat-based Substrates

The pour-through (PT) method is used in greenhouse and nursery production to monitor nutrient availability in soilless substrates. Efficacy of this method is based on the assumption that chemical properties of extracted solutions remain stable from the moment of collection until analysis. Extracted substrate solution can be analyzed directly in the greenhouse or sent to laboratories for complete nutritional analysis; thus, proper sample preservation methods (e.g., filtration and low temperatures) are critical for reducing sample contamination or degradation during storage. However, evidence of how these preservation methods affect chemical characteristics of PT samples is limited. The objective of this study was to evaluate the effect of storage time, storage temperature, and filtration of PT samples on pH, electrical conductivity (EC), and nutrient concentrations from pine bark– and peat-based substrates. PT extracts were obtained from liquid-fertilized fallow pots of either 100% milled pine bark (Expt. 1) or a 4 sphagnum peat: 1 perlite (by volume) substrate (Expt. 2). Aliquots of PT extract were either filtered or nonfiltered and then stored in plastic bottles at −22, 4, or 20 °C. EC, pH, and nutrient concentrations were analyzed at 0, 1, 7, and 30 days after PT sample collection. EC and pH in PT extracts of peat and pine bark, respectively, changed 1 day after collection. Storage time had the greatest effect on nutrient concentrations of samples stored at 20 °C. However, at day 30, nutrient concentrations had also changed in samples stored at 4 and −22 °C. Analytes that fluctuated most in both experiments and across all preservation treatments were dissolved organic carbon, total dissolved nitrogen, NO3−-N, and PO43−-P, whereas Ca2+, Mg2+, and SO42−-S were more stable in PT samples. This research suggests EC and pH should be analyzed immediately, whereas samples requiring nutrient analysis should be filtered immediately after collection, stored at 4 or −22 °C (preferably −22 °C), and analyzed within 7 days of collection.

Influence of rooting media and indole-3-butyric acid (IBA) concentration on rooting and shoot formation of Warburgia ugandensis stem cuttings

This study investigated the influence of different rooting media and indolebutryic acid (IBA) hormone concentration on root and shoot development in stem cuttings ofWarburgia ugandensis. Stem cuttings were treated with three different levels (0.3, 0.6 and 0.8% w/w) of IBA concentration (including a control- no IBA hormone) and propagated in three rooting media (milled pine bark, top forest soil and sand) under non-misting propagators. Data on root and shoot development, callusing, number and length of roots and shoots were analyzed using analysis of variance (ANOVA) and Chi square test. Callusing, root and shoot development were significantly (p<0.05) influenced by rooting media and IBA concentration. Milled pine bark and 0.8% w/w IBA concentration gave the highest percentages of stem cuttings that callused, rooted and shooted (38, 37, 41% and 57, 41, 59%), respectively. Similarly, milled pine bark and 0.8% w/w IBA concentration gave the greatest number and longest roots and shoots per stem cutting. Vegetative propagation of W. ugandensis through stem cuttings can be appropriately achieved by treating the cuttings with 0.8% w/w IBA hormone using milled pine bark as a growth medium. Key words: Warburgia ugandensis, indolebutryic acid (IBA), vegetative propagation, callusing, rooting, milled pine bark.

Cationized milled pine bark as an adsorbent for orthophosphate anions

AbstractMore efficient adsorption media are needed for removing dissolved phosphorus in surface water runoff. We studied the use of cationized pine bark as a sorbent for dissolved phosphorus in water. Cationized pine bark was prepared by treating extracted milled pine bark with polyallylamine hydrochloride (PAA HCl) and epichlorohydrin (ECH) in aqueous medium. Attachment of PAA HCl to the bark was monitored by percentage of weight gain and nitrogen content. Changes in bark surface chemistry were characterized by zeta potential and inverse gas chromatography measurements. Energy dispersive x‐ray analysis and scanning electron microscopy were used to determine changes in chemical composition and morphology of the cationized bark. The cationized bark showed a decrease in the dispersive component of the surface energy and a barely measurable change in the surface acid–base properties. In the pH range 2.5 to 7.9, the cationized bark showed a positive zeta potential, which changed to negative at pH 7.9 or higher. By comparison, the zeta potential of control extracted bark remained negative throughout the pH range of 2.5 to 9. We propose that the reaction of bark with PAA HCl results in a surface network of fixed cationic sites of quaternary ammonium that have mobile chloride ions as counter anions. Preliminary results from batch adsorption experiments indicate that cationized milled bark has an estimated maximum adsorption capacity of approximately 12.65 mg phosphate/g, which compares favorably with that of other well‐known phosphorus sorbents. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1577–1583, 2004

The Efficacy of Ectomycorrhizal Colonization of Pin and Scarlet Oak in Nursery Production

Abstract Two experiments were conducted to assess the effectiveness of ectomycorrhizae inoculation of pin (Quercus palustris) and scarlet oak (Q. coccinea) during nursery production. Experiment 1 tested inoculum and substrate protocol. Vegetative and spore inoculum of Pisolithus tinctorius (Pt) were applied to pin and scarlet oak seedlings. All plants were grown in 0.9 liter (1 gal) containers filled with milled pine bark, sterilized milled pine bark, sterilized mineral soil, or sterilized vermiculite-based substrate. After two months, mycorrhizal colonization rates were assessed qualitatively. Vegetative inoculum was unsuccessful at infecting seedlings of both species when grown in all of the substrates. Best results were 90% and 60% of plants colonized with spore inoculum for pin and scarlet oak, respectively, grown in vermiculite-based substrate. Sixty percent of pin oaks were colonized by Pt in milled pine bark, whereas no scarlet oaks were colonized. Overall, the spore inoculum colonized pin oak at a higher rate than scarlet oak, and vermiculite-based substrate proved superior to the other three substrates for inoculating seedlings with commercial Pt spores. In experiment 2, Pt spore inoculum was applied as a bare root dip on scarlet oak liners before transplanting into 51 liter (15 gal) containers in a pot-in-pot growing system. Pt had a colonization rate of zero, but an indigenous mycorrhizal fungus, Scleroderma bovista (Sb), colonized many of the trees. Height and trunk diameter growth during two years of production were similar for trees colonized and not colonized with Sb. Leaf water potentials were more negative and stomatal conductance was reduced for transplanted colonized compared to not colonized trees during a 10-day dry-down, imposed 50 days after transplanting. Under our conditions, mycorrhizal fungi showed no apparent benefit during production and during initial establishment.

Pine Pole and Post Peelings Have Potential as Blueberry Growing Media and Soil Amendment

Growing southern highbush blueberries in milled pine bark beds ≈15 cm deep has become a popular fruit production system in Georgia and Florida. One of the primary limiting economic factors in this system is the cost of the growing media, which can exceed $10,000 U.S. per ha. In an effort to discover low-cost substitutes for milled pine bark, available waste or low-cost organic materials were screened for there suitability as growing media for southern highbush blueberries. Cotton gin waste, pecan shells, hardwood “flume” dirt, milled composted urban yard waste, composted urban tree trimmings, pine telephone pole peelings, and pine fence post peelings were evaluated. Only pine derived materials had a suitable pH (&lt;5.3). Fresh pine telephone pole peelings (≈25% bark to 75% elongated fibers of cambial wood) and pine fence post peelings (≈75% bark to 25% elongated fibers of cambial wood) were evaluated for several seasons in containers and field trials. The growth index of blueberries in these materials was slightly less or equal to milled pine bark. Surprisingly, nitrogen deficiency was slight or not a problem. The results indicate that pine pole and post peelings may offer an excellent, low-cost substitute for milled pine bark for blueberry production.

Prediction of water‐retention of milled pine bark‐sand potting media from laboratory analyses of individual components

Abstract A mathematical equation which estimates water‐retention of synthesized milled pine bark‐sand pottinq media from laboratory analyses of each medium component was formulated and tested. The equation is the weighted sum of water retained by each component at a specified tension level. Media samples were sequentially subjected to 0‐, 10‐, 50‐, and 100‐cm water tension for 72 hours. Regression equations describing measured and estimated water retention at each pressure level increased linearly with increasing volumetric percent bark. The two regression equations corresponding to each tension level were not statistically different indicating that the equation for estimating water retention is reliable with synthesized pine bark‐sand media.

SHRINKAGE IN TERNARY MIXES OF CONTAINER MEDIA

An equation for predicting shrinkage in 3-component (ternary) container media was devised. The predictive equation was tested using experimental data obtained from sets of mixtures of milled pine bark, sand, and calcined clay. Each set consisted of 66 different combinations of the experimental components. Actual shrinkage data was correlated with theoretical values calculated from the predictive model. Results of the experiment suggest that shrinkage can be used as a factor with linear programing techniques.

Prediction of H‐ion activity of two‐component potting media from analysis of components

Abstract A mathematical equation which predicts H‐ion activity (HA) of container media from laboratory analysis of components was devised and tested. The equation is based on the weighted sum of HA contributed by each component. Both measured and predicted HA increased linearly with increasing volume percent bark in milled pine bark‐sand media. Regression equations describing measured and predicted HA were not statistically different. The predictive equation was also tested on other 2‐component potting mixtures with no statistical differences occurring between measured and predicted HA. Measured pH and pH values derived from the HA predictive equation were in close agreement.

Influence of an Aluminum Amendment on Phosphorus Leaching from a Container Medium

Abstract Columns of an incubated (25°C, 11% volumetric moisture for 30 days) 2 milled pine bark : 1 Canadian sphagnum peat : 1 builders’ sand (by volume) medium amended with the equivalent of 270 g P·m−3 from radioactive superphosphate (8.7% P) and the equivalent of 0, 33, 200, or 1200 g Al·m−3 from aluminum acetate (13.2% Al) were leached daily with 16 ml deionized water. Eighty percent of the 32P amendment leached during days one to 21 from the medium not amended with Al, whereas 0.3% leached when amended with 1200 g Al·m−3. Leachate 32P levels ranged from 840, 711, 91, and 2.0 μg·ml−1 on day 1 to 2.3, 3.3, 7.6, and 0.9 μg·ml−1 on day 77 for the medium with Al amendments of 0, 33, 200, and 1200 g·m−3, respectively.

Rewetting Characteristics of Container Media Composed of Gasifier Residue in Combination with Pine Bark or Peat Moss

Abstract Rewetting of gasifier residue (GR) at 0% of container capacity was greater than milled pine bark (B) or Canadian sphagnum peat moss (P). The percentage of container capacity necessary to obtain 80% rewetting of GR was substantially lower than for either P or B (5%, 23%, and 25%, respectively). Neither the rewetting of B, P, or GR at 0% of container capacity, nor the percentage of container capacity necessary to produce 80% rewetting of these media were affected by Aqua-Gro wetting agent (WA). Addition of GR in excess of 75% substantially increased the percentage of rewetting of both B and P.

Propagation of Blueberry by Softwood Terminal Cuttings in Pine Bark and Peat Media1

Abstract Softwood terminal cuttings of ‘Woodard’ and ‘Tifblue’ blueberry (Vaccinium ashei Reade) rooted best in media containing milled pine bark alone or mixed with equal parts of perlite, compared to sphagnum peatmoss alone or mixed with equal parts of perlite. Percentage rooting, root quality, and percentage marketability of softwood terminal cuttings of Vaccinium ‘Tifton 275’, a complex hybrid of V. corymbosum L. and V. ashei, was unaffected by rooting medium.

Deltic 21EC Phytotoxicity Test on Woody Ornamentals, Alabama, 1981

Abstract Foliar applications of Deltic 21EC were applied to 9 container-grown woody ornamental species to evaluate phytotoxicity or ornamentals that might be oversprayed during lawn treatments for flea or tick control. The experiment was conducted oudoors in full sun at the Auburn University Ornamental Horticulture Field Station, Mobile, AL. Treatments were replicated 4 times for each species in a randomized complete block design. Each replicate was a single plant growing in a 1 gal plastic pot filled with a growing medium of milled pine bark and sandy clay, 5:1, v/v. Sprays were applied over the top of the plants to run-off using a hand-pumped, compressed air sprayer equipped with fan nozzle on Jul 14.

Pine bark ‐ phosphorus relationships

Abstract Columns of milled pine bark were leached weekly with 576 ml of distilled water for 6 weeks and leachates collected. Leachate analysis indicated that significant amounts of indigenous P were leachable. When ‘Helleri’ holly were grown in pine bark with no P applied, 0.08 mg of indigenous P was absorbed. Studies were also conducted to determine if pine bark adsorbs P. The amount of P adsorbed by pine bark, as determined by equilibrium solution analysis, ranged from 0 to 9.7 μg per g of pine bark when solutions of P ranging from 0 to 15 ppm were equilibrated with pine bark for 24 hours. P adsorbed, as determined by analysis of the above ashed pine bark following distilled water leaching, ranged from 0 to 5.3 μg per g of pine bark for the 0 to 15 ppm P treatments, respectively.

Electron microprobe analysis of calcium solution penetration into milled pine bark particles

Abstract Pine bark (Pinus taeda L. and P. elliottii Engelm.) pieces, 2.5 to 5.0 cm diameter, submerged in water became saturated more rapidly in a vacuum than at atmospheric pressure. A test was conducted to determine the extent of Ca solution penetration into smaller milled particles and the effect physical structure of particles has on this process. Particles 2.0–2.8 mm diameter were submerged in a solution of 1000 ppm Ca as Ca(OH)2, placed in desiccators and evacuated to 150 mm Hg of tension. At intervals of 24, 48 and 96 hours samples were removed, freeze‐dried, and cut tangentially to expose the internal phloem. Electron microprobe x‐ray analysis initially showed different Ca concentration in peripheral and central zones and indicated that Ca solution had penetrated the particle and saturation was completed within 96 hours. The progression of Ca penetration was uniform from all edges and indicated that the varied structure of bark tissues did not impede water penetration.

Influence of Initial Moisture Content on the Wettability of a Milled Pine Bark Medium1

Abstract Water absorption curves were developed for air dry peat-vermiculite and pine bark media. Data indicated 70-78% of moisture saturation was attained within 5 days with a peatvermiculite medium while 48 days were required to achieve 58-70% saturation with a milled pine bark medium. Increased water absorption of pine bark after 10 days of wetting suggested that a threshold moisture level within the bark particles is necessary if water uptake is to be enhanced. The threshold moisture content was established at 35% (wet wt basis).