VTechWorks Repository :: Browsing by Author "Bond, Brian H."

Browsing by Author "Bond, Brian H."

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Activity-based product costing in a hardwood sawmill through the use of discrete-event simulation
Rappold, Patrick M. (Virginia Tech, 2006-06-02)
The purpose of this research was to quantify the impact of the log variables: length, grade, and scaling diameter, on the cost of producing hardwood lumber, using the activity-based costing technique. The usual technique of calculating hardwood lumber product costs is based upon traditional cost accounting, where manufacturing costs are allocated to the products based upon the volume of each product that is produced. With the traditional cost accounting procedure, the variation in the resources used to process the logs is not taken into consideration. As a result, when the cost to manufacture the products is subtracted from the market value of the products, the resulting profit levels of the products may not be truly representative of the actual resources consumed in manufacturing the product. Using discrete-event simulation, two hardwood sawmills were modeled and a series of experiments were conducted which would not have been feasible to conduct on the mill floors. Results from the simulation experiments illustrated that the activity-based and traditional cost accounting techniques allocated different amounts of manufacturing costs to the products. The largest difference between the two cost accounting techniques was found to be the amount of raw material costs allocated to the products. For one of the sawmills modeled, log grade was identified as having the greatest influence on determining product costs and total manufacturing costs. Results from the model of the second sawmill however demonstrated that log diameter had a greater impact on determining product costs and total manufacturing costs. The commonality of the results from the two simulation models was that the differences in the volume of lumber produced, between the logs that were studied, was a critical component in determining which log parameter had the most effect on changing the dynamics of the sawmill system. To enable hardwood managers a more precise method of allocating raw material costs to the lumber products, a methodology was developed that uses the principles of activity-based costing to allocate raw material costs. The proposed methodology, termed the lumber yield method, uses lumber yield values from logs with similar characteristics to allocate raw material costs to the lumber products. Analysis of the output from the simulation models illustrated that with the lumber yield method, the amount of raw material costs allocated to the products was not significantly different than the amount allocated by the activity-based costing method. The calculated raw material costs of the products were however, found to be significantly different between the lumber yield method and the traditional volume costing method.
Adhesive Bonding Performance of Thermally Modified Yellow Poplar
Masoumi, Abasali; Balma, Francisco Xavier Zambrano; Bond, Brian H. (2023-10-16)
Thermal modification of wood changes its chemical, physical, and structural properties, which may affect adhesive bondline quality and bonding performance. This research compared the effect of thermal modification on the adhesive bonding performance of poplar (Liriodendron tulipifera) wood. Samples were prepared from thermally modified and unmodified yellow poplar using one-component polyurethane (PUR) and polyvinyl acetate (PVA), as they are adhesives used in wood products. Microscopic properties of the bondlines were investigated to understand shear performance and durability. Adhesive line thickness, penetration, shear strength, and moisture durability were measured, and failure modes were recorded. Thermal modification negatively affected the wood and adhesive interaction by reducing penetration (31.2% in PUR and 29% in PVA), therefore creating a thicker adhesive line (70% in PUR and 2% in PVA) and consequently causing a significant reduction in the shear strength of both adhesive types (27% in PUR and 36% in PVA) compared with non-modified specimens. The PUR adhesive had higher shear strength than PVA by 2.7% in non-modified and 14% in thermally modified wood.
Analysis of electricity consumption: a study in the wood products industry
Quesada, Henry Jose; Wiedenbeck, Janice K.; Bond, Brian H. (2016-10)
This paper evaluates the effect of industry segment, year, and US region on electricity consumption per employee, per dollar sales, and per square foot of plant area for wood products industries. Data was extracted from the Industrial Assessment Center (IAC) database and imported into MS Excel. The extracted dataset was examined for outliers and abnormalities with outliers outside the quantile range 0.5-99.5 dropped from the analysis. A logarithmic transformation was applied to eliminate the skewness of the original data distributions. Correlation measurements indicated a moderate association between the response variables; therefore, a multivariate analysis of variance test was performed to measure the impact of the three factors: industry type, year, and region, simultaneously on all response variables. The results indicated some effect associated with all three factors on the three measures of electricity consumption. Subsequently, univariate ANOVA tests were conducted to determine the levels of the factors that were different. Most levels of industry type were associated with significantly different energy consumption, an expected result since some of the industries are more energy intensive than others. The industries in Standard Industry Code (SIC) 2493 (reconstituted wood products) are the groups with the highest electricity consumption with means of 38,096.28 kWh/employee, 0.86 kWh/sales, and 154.14 kWh/plant area while industries grouped in SIC 2451 (mobile homes) have the smallest consumption with means of 6811.01 kWh/employee, 0.05 kWh/sales, and 9.45 kWh/plant area. Interestingly, differences in regional consumption were found to be linked to the proportion of industry types by region. Data analysis also indicated differences in electricity consumption per employee for the factor year, but for the other response variables, no differences were found. These main results indicate that industries in the wood products sector have different electricity consumption rates depending on the type of manufacturing processes they use. Therefore, industries in this sector can use these comparisons and metrics to benchmark their electricity consumption as well to understand better how electricity costs might vary depending on the region they are located.
Analysis of Energy Recommendations in the U.S. Wood Products Industry
Bauman, Michael Justin (Virginia Tech, 2016-06-25)
As energy prices and demand are projected to increase globally and markets become more competitive nationally and internationally; the wood products industry must find ways to remain relevant. By: 1) analyzing energy-saving recommendations contained in the IAC database; 2) comparing those recommendations by criteria such as cost, savings, and payback period; 3) identifying recommendations that incorporate lean manufacturing principles; and 4) investigating the practices and perceptions of manufacturers at the facility level, this project provides information for identifying the greatest opportunities for energy management among U.S. wood product manufacturers. Results from the analysis of the IAC database show that wood product manufacturers had a low implementation rate of energy recommendations ranked purely by cost, savings, and payback period among wood product manufacturers suggesting they were not focused on implementing energy recommendations specifically based on those criteria. While some recommendations were found to be statistically different in at least one criteria: cost, savings, or payback period between wood and non-wood manufactures as well as primary and secondary wood manufacturers, only two recommendations had practical differences, large payback periods, between primary and secondary wood manufacturers. Twenty-four of 192 energy recommendations were classified as lean-based energy recommendations using the Kirby and Green (2003) methodology, however, there was no clear evidence to suggest the lean-based energy recommendations were superior in terms of cost, savings, or payback period when compared to simple energy recommendations. Interviews with primary and secondary manufacturers revealed a lack of commitment to energy performance improvement and the reported barriers of implementation among a small sample of wood products manufacturers suggests that the dissemination of energy management knowledge and benefits is a problem.
Assessing Eastern White Pine Lumber Production and Use in the Eastern United States
Duvall, Paul Mason (Virginia Tech, 2003-02-26)
A survey of primary and secondary manufacturers of eastern white pine (EWP) was executed within three regions of the Eastern US: New England, Mid-Atlantic, and Lake States. Two hundred ninety-six usable questionnaires were returned in total, with 185 coming from primary manufacturers and 111 from secondary manufacturers of EWP. The data from these surveys was used to identify differences in market characteristics between the three regions producing EWP, and also between primary and secondary industries. It was found that markets for EWP were growing in all three regions. Overall growth among primary manufacturers was estimated at 6.9% during the next 5 years, with 18.9% expected from the secondary industry. Industry members in all three regions reported that they would be able to sell more EWP products if they could get more logs. This theme of log shortage and availability was present in all three regions, and likely has to do with the loggers in those regions and how much importance they place on harvesting EWP. Results indicated that primary manufacturers overestimated how highly secondary manufacturers valued machinability, product range, and the rustic look of EWP, as significant differences were found in all of those categories. This implies that sawmills need not emphasize these aspects as much as they have been, as they are less important to customers than sawmills may have believed. Conversely, primary manufacturers underestimated how highly secondary manufacturers valued on-time delivery, consistent price, JIT delivery, and flexible payment options. These results suggest that EWP sawmills would be able to gain an advantage by putting more effort into providing these services. The effect of imported species appeared to be less than anticipated, with more than one-half of both primary and secondary respondents reporting that imports had had no impact on their operation. However, primary manufacturers were more likely to report a negative effect than their secondary counterparts, with negative response rates at 41% and 20%, respectively.
Assessment of Cross Laminated Timber Markets for Hardwood Lumber
Adhikari, Sailesh (Virginia Tech, 2020-09-25)
The goal of this study was to assess the potential of using hardwood lumber in CLT manufacturing. The goal was achieved by addressing four specific objectives. The first objective was to collect CLT manufacturers' perspectives for using hardwood lumber in the current manufacturing setup. The second objective was to determine hardwood sawmills' current ability to produce structural grade lumber (SGHL) from low value logs as a product mix through a survey of hardwood lumber producers in the US. The third objective was to conduct a log yield study of SGHL production from yellow poplar (YP) logs to produce 6'' and 8'' width SGHL to match the PRG 320 requirements. The fourth objective was to determine CLTs' production cost using SGHL and compared it with the CLTs manufactured from southern yellow pine (SYP). The results suggest that all three CLT industries visited and interviewed had sufficient technology to produce hardwood CLTs. The production of hardwood CLTs was mainly limited by the quality and quantity of lumber available. The hardwood sawmill survey results indicated that, currently, less than 10% of the sawmills had all the resources required to produce SGHL. The current ability of the sawmills was measured based on the resources necessary to begin SGHL production. Forty percent of the sawmills would require an investment in sawing technology to saw SGHL, 70% would require employing a certified lumber grader, and 80% would require a planer to surface lumber. Another significant finding was the sawmills' willingness to collaborate with other sawmills and lumber manufacturers. More than 50% of sawmills were open to potential collaboration with other stakeholders if necessary, which is crucial to commercializing SGHL for a new market. The log yield study of yellow poplar helped demonstrate that the mixed grade lumber production method to convert lumber from lower quality zones as SGHL yields higher lumber volume for sawmills and at the same time reduces lower-grade lumber volume. On average, SGHL production increased lumber volume by more than 6% compared to only NHLA grade lumber production when 65% of the lumber was converted to SGHL. The volume of lower lumber grades from 2 common and below decreased from an average of 85% to less than 30% when producing SGHL as a product mix with NHLA grade lumber. This study observed more than 95% of SGHL as Number 3 and better lumber grades. At estimated lumber value, 2x6 and 2x8 SGHL and NHLA grade lumber production as product mix from a log generate higher revenue for all log groups except for the diameter 13" logs. A lower percentage of higher-grade lumber was observed for diameter 13’’ logs than other log groups from this experiment, which resulted in lower revenue. Production cost of CLTs was determined based on the lumber value to manufacture 40' x 10' plain panels with different combinations by lumber grade of yellow poplar and southern yellow pine lumber alone. Production cost was determined by assuming that lumber value contributes 40% of CLTs' total production cost. The 3- ply CLT panels were manufactured using S. Selects lumber in a major direction, and No 1-grade lumber in the minor direction from YP had a production cost of $662.56 per cubic meter, which cost only $643.10 when SYP lumber was used at referenced lumber value. This study concludes that CLT panels from YP cost 3-7 % more than SYP-CLTs at the referenced lumber values.
Barriers Impacting United States Advanced Biofuel Projects
Withers, Jeremy W. (Virginia Tech, 2016-07-14)
Although the 2005 EPAct was enacted to help bolster the emerging biofuel industry, 52% of advanced biofuel projects were closed or shut down by 2015. However, there are no complete lists of barriers that impeded these projects. The goal of this study was to develop a framework of barriers impeding success of advanced biofuel projects by conducting a literature review of barriers, spatial analysis of status, survey of barriers, and determination of coproducts and byproducts and their marketing and distribution barriers from the industry stakeholders. The spatial analysis indicated 59 biofuel projects were attempted, and their Eastern and Western location by status was not a barrier. Using Grounded Theory, nine barriers were derived and aggregated in major categories, including product development, strategy, technology, competition, energy costs, funding, government, suppliers, and third-party relations. A contingency analysis was conducted relating their status to internal and external barriers, indicating no relationship between type of closing and type of barrier. Next, the number of barriers was expanded to 23, and a survey was conducted to gain knowledge on these barriers from industry stakeholders. When comparing the barriers by stakeholders, there were differences based on status, type, and technology of the projects. In addition, the survey and discussion identified 79 barriers different across years, type of industry (pilot, demonstration, or commercial), status (open, closed, or planning), and technology (thermochemical, biochemical, or hybrid). Forty-seven coproducts and byproducts and many unknown barriers to their marketability and distribution were determined and ranked by primary and secondary barriers. These extensive lists of barriers and coproducts will aid future biofuels projects in their planning, research, and development stages.
A Business Model for a Red Oak Small Diameter Timber Processing Facility in Southwest Virginia
Perkins, Brian Russell (Virginia Tech, 2006-12-12)
The conversion of red oak small diameter timber (SDT) into solid wood products was investigated. The objectives of this research were to 1) determine the yield of lumber, pallet and container parts, and residues from SDT and the market potential for these products; 2) determine the economic feasibility of a SDT sawmill and pallet part mill located in Southwest Virginia; 3) develop a business plan for a SDT sawmill and pallet part mill located in Southwest Virginia. The methods for this research consisted of resource, yield and economic analyses, and the development of a business model. The resource analysis indicated an ample supply of red oak SDT available in Southwest Virginia. The yield analysis used red oak SDT logs, which were manufactured into lumber, container parts and wood residues. The yield of 3" wide container parts from cants varied from 63% to 66%. The 1" nominal lumber produced was mainly 2A and 3A, 74%, and 24% was 1 common. The economic analysis utilized break even, net present value and internal rate of return analyses to determine the economic feasibility of utilizing red oak SDT. The results of the study indicated that the sawmill-only processing level scenario is not economically feasible given the specified conditions and assumptions. However, the results showed that the sawmill and pallet part mill, actual yield scenario at $35/ton delivered log cost is economically feasible. The hypothetical business model for Southwest Custom Hardwoods was economically feasible. The final net present value was calculated to be over $750,000 and the final internal rate of return was 11%. Future yield studies should weigh logs so that the yield of residues and solid wood products can be directly compared. Future research into the utilization of hardwood SDT should include yield studies of other species and other product mixes.
Changes in the Chemical Composition and Decay Resistance of Thermally-Modified Hevea brasiliensis Wood
Durgante Severo, Elias Taylor; Calonego, Fred Willians; Sansigolo, Claudio Angeli; Bond, Brian H. (PLOS, 2016-03-17)
In this study the effect of thermal treatment on the equilibrium moisture content, chemical composition and biological resistance to decay fungi of juvenile and mature Hevea brasiliensis wood (rubber wood) was evaluated. Samples were taken from a 53-year-old rubber wood plantation located in Tabapuã, Sao Paulo, Brazil. The samples were thermally-modified at 180°C, 200°C and 220°C. Results indicate that the thermal modification caused: (1) a significant increase in the extractive content and proportional increase in the lignin content at 220°C; (2) a significant decrease in the equilibrium moisture content, holocelluloses, arabinose, galactose and xylose content, but no change in glucose content; and (3) a significant increase in wood decay resistance against both Pycnoporus sanguineus (L.) Murrill and Gloeophyllum trabeum (Pers.) Murrill decay fungi. The greatest decay resistance was achieved from treatment at 220°C which resulted in a change in wood decay resistance class from moderately resistant to resistant. Finally, this study also demonstrated that the influence of thermal treatment in mature wood was lower than in juvenile wood.
Characterization of Wood Features Using Color, Shape, and Density Parameters
Bond, Brian H. (Virginia Tech, 1998-02-09)
Automated defect detection methods allow the forest products industry to better utilize its resources by improving yield, reducing labor costs, and allowing minimum lumber grades to be utilized more intelligently. While many methods have been proposed on what sensors and processing methods should be used to detect and classify wood features, there exists a lack of understanding of what parameters are best used to differentiate wood features. The goal of this research is to demonstrate that by having an in depth knowledge of how wood features are represented by color, shape, and density parameters, more accurate classification methods can be developed. This goal was achieved through describing wood features using parameters derived from color and x-ray images and characterizing the variability and interrelationships of these parameters, determining the effect of resolution and species on these relationships, and determining the importance and contribution of each parameter for differentiating between wood features using a statistical prediction model relating feature types to the parameters. Knots, bark pockets, stain and mineral streak, and clearwood were selected as features from red oak, (Quercus rubra), hard maple, (Acer saccharum), and Eastern white pine (Pinus stobus). Color (RGB and HSI), shape (eccentricity and roundness), and density (gray-scale values) parameters were measured. Parameters were measured for each wood feature from images and parameter differences between feature types were tested using analysis of variance techniques (ANOVA) and Tukey's pairwise comparisons with a=0.05. Discriminant classifiers were then developed to demonstrate that an in-depth knowledge of how parameters relate between feature types could be used to develop the best possible classification methods. Classifiers developed using the knowledge of parameter relationships were found to provide higher classification accuracies for all features and species than those which used all parameters and where variable selection procedures had been used< It was determined that differences exist between all feature types and can be characterized and classified based on two color means, one color standard deviation, the mean density, and a shape parameter. A reduction in image resolution was determined not to affect the relationship of parameters. For different species, the intensity of features was to be related to the intensity of clearwood. The ability to explain classification errors using the knowledge gained about feature parameters was demonstrated. This knowledge could be used to reduce future classification errors. It was determined that combining parameters collected using multiple sensors increases classification accuracy of wood features. Shape and density were found not to provide good classification variables for features when used separately, but were found to contribute to classification of features when used with other parameters. The ability to differentiate between the feature types examined in this research was found be equal when using the RGB or HSI colorspace.
Comparison of the Economic Feasibility between Conventional and Vacuum Drying for 4/4 Red Oak
Brenes-Angulo, Oxana; Bond, Brian H.; Kline, D. Earl; Quesada, Henry Jose (Forest Products Society, 2017-01-01)
Vacuum drying of wood is a method to reduce drying time and inventory; however, there is limited information regarding the economic feasibility for vacuum drying 4/4 red oak compared with traditional drying methods. The benefits of this technology, mainly dramatically reduced drying times and higher flexibility, must be weighed against the higher initial capital investment. The goal of this project was to compare the economic feasibility, using capital budgeting techniques, of conventional drying and vacuum drying for 4/4 red oak lumber. The analysis was conducted for two actual flooring manufacturers. Conventional drying for this analysis was considered to be air-drying plus kiln drying, which is commonly done with red oak. The vacuum technology considered used hot platens for heating the wood. Species, thickness, drying methods, and lumber demand compared, both drying methods (conventional and vacuum drying) were determined to be economically feasible. However, vacuum drying had a slightly higher net present value, cost–benefit ratio, and sensitivity analysis than conventional drying, making it a slightly better investment for drying 4/4 red oak. The initial tied-up inventory and its respective cost in the conventional drying scenario represents an opportunity cost that can be recovered using vacuum drying. This recovered cost can result in freed capital that can be invested elsewhere to increase competitiveness.
Design and operation of a solar heated dry kiln
Bond, Brian H. (Virginia Cooperative Extension, 2020)
While lumber can be air dried, the humidity in most localities prevents the lumber from reaching the moisture content required for the stability needed for interior use. A dry kiln is required to dry lumber to the necessary final moisture content and does so fairly rapidly. This publication discusses the design and operation of a solar-heated lumber dry kiln that is designed to be inexpensive to construct and simple to operate.
Design and Operation of a Solar-Heated Dry Kiln
Bond, Brian H. (Virginia Cooperative Extension, 2020-12-08)
This publication discusses the design and operation of a solar-heated lumber dry kiln that is designed to be inexpensive to construct and simple to operate.
Design and Operation of a Solar-Heated Dry Kiln
Bond, Brian H. (Virginia Cooperative Extension, 2009-05-01)
Discusses the design and operation of a solar-heated lumber dry kiln that is designed to be inexpensive to construct and simple to operate. Includes plans.
Developing an Evaluation Program for Lumber Drying Operations in Bolivia
Espinoza, Omar A. (Virginia Tech, 2006-05-01)
The Bolivian forest products industry has experienced substantial growth during the last ten years. Exports of value-added products have largely replaced logs and green lumber, and raw materials for wood products have shifted to lesser used species. Important investment has taken place in lumber drying capacity, which unfortunately was not always accompanied by sound drying practices. Several non-governmental organizations, with U.S. financial aid, are currently supporting the industry with technical assistance. This project assists these efforts by assembling much needed information regarding lumber drying, and providing tools for performance measurement of drying practices. A survey was conducted among Bolivian companies to determine lumber drying capacity, technology and practices. Results showed a total drying capacity of 6,104,250 board feet in 167 kilns. Technology and practices used are highly variable. Thirty six percent of kilns are home-made, and 59% are European commercial brands. Upon completion of the survey, a set of analytical tools was developed and tested in six Bolivian firms. These tools were designed to systematically evaluate lumber drying operations and formulate actions for improvement. Equilibrium moisture content (EMC) during storage, manufacturing and shipping was monitored in plants located in three Bolivian cities and inside containerized shipments of wood products. Findings showed differences between EMC and lumber moisture content from -1% to 7%. Differences between EMC inside dry-lumber storage and processing facilities varied between 0% and 3.6% and were greatly influenced by facility configuration. Climate during shipment of wood products largely depended on packaging materials and methods, which attenuate sharp changes in ambient conditions. Monthly values for outdoor EMC for the main cities of Bolivia were calculated based on historic weather data and are reported.
Development of a Tool to Measure the Effectiveness of Kaizen Events within the Wood Products Industry
Erdogan, Sevtap (Virginia Tech, 2015-09-04)
Kaizen implementation and other continuous improvement practices can be used by companies to lower manufacturing costs and increase product value. Kaizen activities are one way that wood products companies can increase their competitiveness. Being able to measure the effectiveness of Kaizen events is important to factors that contribute to Kaizen effectiveness as well as identifying the success of Kaizen implementation. However, little research has focused on the implementation of Kaizen and other continuous improvement methods within the wood products industry or on the perceptions of employees within this industry regarding either the motivators for, barriers to, and effectiveness of perceptions of Kaizen, or the drivers affecting Kaizen implementation. The goal of this research is to develop a tool to measure the effectiveness of Kaizen and to apply this tool to companies within the wood products industry. To accomplish this research goal, a case study approach was used in examining how two U.S. wood products companies implemented Kaizen and other continuous improvement initiatives and how employees at these companies viewed such implementation. As part of this case study, interviews were conducted with staff in each company and surveys were administered to production and non-production employees at each company. A tool was developed to measure the perceived effectiveness of Kaizen events, and this tool was tested using the survey data were collected from each company. The results from these analyses show statistically significant differences in how production employees across companies viewed the following: motivators related to cost and quality outcomes, as well as the success of other companies, as motivators for Kaizen; and barriers related to middle management, time, money, technology, and poor past experiences. Poor past experience with Kaizen were also viewed significantly differently by production and non-production employees in one of the companies studied. The results also show that perceptions of productivity improvements were the most significant predictor of the perceived effectiveness of Kaizen implementation. These results and the development of a tool to measure Kaizen will help guide and improve future Kaizen and other continuous improvement efforts within the wood products industry and provide insights for future research.
Development of tension and compression creep models for wood using the time-temperature superposition principle
Bond, Brian H. (Virginia Tech, 1993-06-03)
To date there are no long-term creep models or practical methods to investigate the effect of creep on the safety and serviceability of modem wood structures and structural wood composites. Long-term creep models were developed for wood in tension and compression using the Time-Temperature Superposition Principle (TTSP). The principle states that the long-term response of a polymer at lower temperature is equivalent to the short-term response at a higher temperature. Accelerated creep tests were conducted in tension and compression using small clear specimens of Douglas-fir, southern pine and yellow-poplar. The specimens were tested at moisture contents of 6 %, 9 %, and 12 %, and at temperatures between 20°C and 80°C. The strain was measured using bonded strain gages. The individual creep compliance for each temperature was shifted along the log-time axis to obtain a "master" curve that describes the creep response of the specimens. All compliance curves also required vertical shifting. The experimental horizontal shift factors followed the Arrhenius formulation that describes the shift factor relation for polymers in the glassy region.
Dimensional Stability and Equilibrium Moisture Content of Thermally Modified Hardwoods
Masoumi, Abasali; Bond, Brian H. (BioResources, 2024-01-04)
The dimensional stability and equilibrium moisture content (EMC) of thermally modified hardwoods were studied. Lumber of yellow-poplar (Liriodendron tulipifera); red oak (Quercus borealis); white ash (Fraxinus americana), red maple (Acer rubrum); hickory (Carya glabra), and black cherry (Prunus serotina) were modified in industrial thermo-vacuum system. The water absorption rate, EMC, swelling, anti-swelling efficiency, shrinkage, anti-shrinkage efficiency, and anisotropy of the specimens were measured and compared to unmodified wood. The results show that thermal modification significantly decreased water absorption of wood which leads to improved dimensional stability. Specifically, thermally modified wood showed reduced EMC (22% in hickory to 59% in red maple), increased water absorption repellent (14.9% in black cherry to 29.6% in yellow-poplar), increased anti-swelling efficiency (14.2% in hickory to 71.4% in ash), increased anti-shrinkage efficiency (23.5% in red maple to 65.6% in ash), and reduced anisotropy coefficient (4.7% in red oak to 31.9% in black cherry).
Evaluation of Methods to Control Mold on Hardwood Pallets
Blount, Thomas Richard (Virginia Tech, 2013-06-14)
The objectives of this project were:
1.ï¿½ï¿½ï¿½ï¿½To compare the drying cost and drying time for oak and poplar pallets for the following mold mitigation strategies for hardwood pallets: air drying, forced air drying (fan shed), kiln drying to 25% moisture content and chemical treatment, and
2.ï¿½ï¿½ï¿½ï¿½Develop and evaluate a procedure for preventing and controlling mold growth on heat treated hardwood pallets
Twenty red oak pallets and twenty yellow-poplar pallets were tested for each drying method to compare costs and to determine drying times. ï¿½Additional pallets were obtained to conduct a more thorough air drying procedure. ï¿½Drying data was extrapolated to allow estimates of the drying time from green (83% moisture content for poplar and 64% moisture content for oak) to 25%. ï¿½
After the pallets reached the desired 25% moisture content, they were placed in a 40ï¿½" enclosed trailer, inoculated with mold (Aspergillus, Stachybotrys, and Penicillium) and were left undisturbed for a period of 14 days. ï¿½After the 14 day incubation period, the pallets were inspected for mold using the ASTM D-4445 Standard Test Method for Fungicides for Controlling Sapstain and Mold on Unseasoned Lumber. ï¿½
A comparison of drying costs was then conducted to determine which method was the most cost efficient based on the data obtained in this study. ï¿½The cost to treat the pallets with each treatment was calculated including electrical cost, labor, and tax values. ï¿½In addition to the cost comparison, a Net Present Value (NPV) was calculated to determine which method produced the best outcome over a longer period of time.
Two heat treatment and drying schedules were then developed to meet both IPPC-ISPM #15 requirements and achieve the desired 25% moisture content with minimal degrade. ï¿½This was accomplished by testing several HT/drying schedules on green yellow-poplar and white oak pallets until the pallets met the criteria for being heat treated and had minimal degrade. ï¿½The schedules developed are a modified oak HT/KD schedule that required 30 hours to complete and a modified poplar HT/KD schedule that required 16 hours to complete.
The results demonstrated that that mold would not grow on the pallets stored in an enclosed container when the dew point is not reached. Air-drying pallets, chemical application in conjunction with air-drying pallets, fan shed drying pallets and kiln drying pallets to a 19-24% moisture content was demonstrated to prevent mold growth on oak and yellow poplar pallets. Estimates for the time required to dry yellow-poplar and oak pallets to 19% and 25% moisture content were developed for air-drying, forced air-drying and kiln drying for the conditions experienced in Blacksburg, VA between 7/30/2008 and 11/10/2008. Air-drying pallets was found to have the lowest daily operational cost but not the lowest total drying cost. ï¿½Fan shed drying had the lowest drying cost to achieve 25% moisture content. ï¿½Kiln drying was the most expensive daily and total cost, but yielded the fastest method of drying pallets to 25% moisture content. A NPV cost comparison showed that over a 3 year (36 month) time period, fan shed drying is the most cost effective method of drying pallets based on the values used in this study. Given the environmental conditions experienced between 7/30/2008 and 11/10/2008, no mold grew on the air-dried, fan shed, and kiln dried pallets during the drying process.
Expanding Markets and Industrial Practices for Thermally Modified Wood
Gonzalez, Juan Jose (Virginia Tech, 2020-06-19)
Thermally modified wood (TMW) contains no toxic components and is recommended for its durability, levels of equilibrium of moisture content, and dimensional stability performance. A limitation of TMW is the lack of market acceptance and products due to insufficient information regarding the performance of commercially available products. The goal of this project was to improve the market penetration and industrial processes of TMW. The first objective was to study the perception of TMW products from architects in North America using a survey instrument. Results revealed that information regarding TMW is not reaching the audience for TMW, and that providing knowledge regarding technical and marketing aspects of TMW is essential to increase the market share. The second objective consisted of the evaluation of the variability of the physical and mechanical properties of three thermally treated species manufactured in North America. Results showed that the performance of the commercially produced material was similar among the three companies, where only in seven out of 24 properties had statistical differences. Properties that were significantly different, did not have large enough differences in means to be realistically noticed by customers and all were highly different from untreated wood. The final objective involved the implementation of Lean thinking to the manufacturing process of TMW with the goal of improving the process with a direct impact on cost and waste reductions. Three companies were used as case studies for the production process. The implementation of Lean thinking in the process proposed a reduction in lead times from 55.47 days to 23.20 days, with an increase in value-added activities from 1% to 6%. Most of these gains were obtained through a reduction in inventory levels.

Browsing by Author "Bond, Brian H."

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