David B. DeVallance

Investigation of hardwood biochar as a replacement for wood flour in wood–polypropylene composites:

The overall goal of this project was to combine biochar (BC) with plastic and wood residue to create novel composite products. Little to no research has been conducted on combining BC with other materials to form a composite. In this research, BC was used as a partial and full replacement material for wood flour and was combined with polypropylene to manufacture composite materials. The resulting wood/BC/plastic composites were evaluated for various mechanical and physical properties. The composites fabricated with 25% BC had the highest average flexural strength and modulus of elasticity. Composites fabricated with 5% BC had the highest average tensile strength and tensile elasticity. Composites fabricated with 40% BC had the lowest average 24- and 48-h water absorption percentage. The findings suggested that BC has the potential to be a replacement for traditional wood in a variety of composite applications.

The effect of bio-carbon addition on the electrical, mechanical, and thermal properties of polyvinyl alcohol/biochar composites

The composites of polyvinyl alcohol and bio-carbon (i.e. biochar) were prepared by a solution casting method to investigate their electrical conductivity and mechanical and thermal properties. The polyvinyl alcohol/biochar composites filled with 2 wt% and 10 wt% biochar exhibit a similar electrical conductivity to most carbon nanotube and graphene reinforced polyvinyl alcohol composites. Results of mechanical tests indicate that addition of the biochar reduced the tensile strength of the polyvinyl alcohol/biochar composites. However, the tensile modulus and storage modulus above the glass transition temperature were improved through the addition of biochar. The results of thermal gravimetric analysis and differential scanning calorimetry indicated that addition of biochar increased the thermal decomposition temperature of polyvinyl alcohol/biochar composites. These results demonstrate that biochar holds great potential for replacing the carbon nanotubes and graphene as a filler of polymers in electrical applications.

Log Sawing Practices and Lumber Recovery of Small Hardwood Sawmills in West Virginia

A total of 230 logs from two species, red oak (Quercus rubra) and yellow poplar (Liriodendron tulipifera), were measured in five typical hardwood sawmills across West Virginia to evaluate log sawing practices and lumber recovery. Log characteristics such as length, diameter, sweep, taper, and ellipticality were measured in sawmills, while log scale and grade were determined by using the US Department of Agriculture Forest Service grading rules. The characteristics of sawing equipment, such as headrig type, headrig kerf width, and sawing thickness variation, were recorded during the measurement process. A general linear model was used to statistically analyze the relationship between lumber recovery and characteristics of logs and sawing practices. Results indicated that factors such as log grade, log diameter, species, log sweep, log length, and some two-factor interactions significantly affected lumber value and volume recovery.

Appalachian hardwood product exports: an analysis of the current Chinese market.

A mail survey of Appalachian hardwood product exporters was conducted in the fall of 2008 to analyze the export practices for Appalachian hardwood products, specifically the volume of hardwood products exported to the Chinese market, their preferred species, and potential and existing trade barriers between US producers and Chinese customers. Results of the survey showed that the most frequent export destinations of Appalachian hardwood products were Europe, China, Canada, Mexico, and Japan. In 2007, approximately 11.4 million board feet (MMBF, Doyle scale) of hardwood logs and 145.3 MMBF of hardwood lumber were exported to China by the respondents. Approximately 37 percent of the respondents who exported hardwood products to China exported red oak logs, followed by white oak, black walnut, black cherry, and hard (sugar) maple. The top species of hardwood lumber exported to China were red oak, white oak, yellow poplar, black walnut, hickory, cherry, hard maple, and soft maple. Respondents indicated that transportation freight costs and payments are the limiting factors when considering expanding business overseas. The continued decreasing hardwood price has put more pressure on hardwood products exporters to maintain profit margins. Because of the current economic downturn, hardwood production in the Appalachian hardwood region has declined by more than 40 percent. Exports of hardwood products to China will be affected to some extent. However, it is expected that China will remain an important overseas market in the near future.

Scientifically advanced woody media for improved water quality from livestock woodchip heavy-use areas

Overwintering cattle on pastures in many areas can damage the pasture and lead to impaired water quality. During these times, use of a woodchip heavy-use area (HUA) presents advantages such as a soft, supportive, and dry foot surface for animals and protection of the pasture and pasture soils. However, woodchip HUAs can also be a centralized source of high nutrient loads due to their drainage outflows. A column study was conducted to assess the nutrient load reduction potential of: 1) six types of wood media (including torrefied wood media and biochar) that could be used in a woodchip HUA versus a gravel control, and 2) providing a 48 h retention time within the wood media to enhance nitrogen removal through denitrification. The woody media provided significant liquid waste volume reduction compared to the gravel in simulated events (53%–61% vs. 39% reductions, respectively), and there may be additional liquid storage capacity in the woodchips not utilized during these rapid events. Substantial total nitrogen removal by the wood treatments (mean removal efficiencies >50%) was observed across the simulated events, although nitrate leaching also occurred. Nitrate removal was enhanced during the 48 h retention test which showed removal was governed by availability of labile carbon (i.e., fresh woodchips exhibited >70% nitrate removal). The retention test also indicated biochar mixtures provided some of the best total phosphorus removal, but the greatest benefits across all parameters was provided by the Mixed Hardwood treatment.

Advanced Cellulosic Nanocomposite Materials

Biomass, especially woody biomass, represents the most important sustainable resource which can be used as feedstock for producing biofuels and bioproducts. In the past decade, overdependence on petroleum products has consistently increased. Biodegradable products from renewable materials are becoming increasingly more attractive due to escalating prices and shortages of crude oil. Cellulose, synthesized mainly in biomass by photosynthesis, is the most abundant natural biopolymer in the world. Natural cellulosic fibers, particles, fibrils (micro and nano scale), and crystals/whiskers are attractive replacements for manmade fibers (e.g., glass and aramid fibers) used as reinforcement and fillers when making environmentally friendly products. These cellulosic materials have many advantages including: renewable, low cost, low density, low energy consumption, high specific strength and modulus, high sound attenuation, nonabrasive, and a relatively reactive surface. Recent research has focused on determining how to use biomass effectively as low cost, environmentaly friendly raw materials in many products while reducing the dependence on petroleum based resources. In the past two decades, research and manufacturing efforts have focused on using natural fibers to replace artificial fibers such as glass fibers for reinforcement material and fillers and to make environmentally safe products (George et al., 2001). Fibrils (in micro and nano scale) isolated from natural fibers have much higher mechanical properties as compared to original fibers. Given this, important research is being conducted on generating fibrils and combining them with polymers to form nanocomposites with the expectation of improving strength and stiffness as compared to composites reinforced with artificial fibers (Berglund, 2005; Cheng et al., 2007a; Cheng et al., 2007b; Cheng et al., 2009b; Herrick et al., 1983; Turbak et al., 1983; ). Microfibres are defined as cellulose fibers 0.1-1 μm in diameter, with a corresponding minimum length of 5-50 μm (Chakraborty et al., 2006). Franks (1987) defined nanotechnology as “the technology where dimensions or tolerances in the range 0.1 to 100 nm (from the size of an atom to the wavelength of light) play a critical role”. The definition of nano-size material has broadened significantly to include a large variety of systems that have at least onedimension at the nanometer scale (1-100 nm) (Jordan et al., 2005). As one of the next generation of environmentally friendly materials, bio-based nanocomposites have grown rapidly and include composites that are completely biodegradable (both the fibril and polymer matrix are biodegradable) and partly biodegradable (at least the fibril is biodegradable).

Impact Assessment of the 2008 to 2010 Economic Downturn Period on Appalachian Hardwood Sawmill Operations

A mail survey was conducted in the fall of 2010 to investigate the impacts of the 2008 economic downturn on sawmill production, employment, and marketing in the Appalachian region. The mail survey was sent to 776 hardwood sawmills in the region and 58 valid responses were used in the study. It was determined that the average number of employees per mill had decreased from 42 to 30, a reduction of 29 percent during the period. At the same time, annual operating hours decreased 9 percent and weekly lumber production fell by 26 percent. Additional information collected with the survey indicated that the average log inventory reported by the responding mills was sufficient to allow production for 6 weeks. Weekly chip and sawdust production was reported as 139 and 81 tons, respectively. Sixty-seven percent of the reporting mills indicated they had changed their marketing strategies as a result of the downturn. Forty-six percent of the respondents reported they were exporting production to overseas markets.

Affordable Home Builder Demand for Green and Certified Wood Products

ABSTRACT Annual new housing starts in the United States decreased dramatically between 2005 and 2012. Consequently, products that are heavily tied to new housing starts, such as flooring, cabinetry...

Testing of tactile sensors for space applications

There is a need to integrate tactile sensing into robotic manipulators performing tasks in space environments, including those used to repair satellites. Integration can be achieved by embedding specialized tactile sensors. Reliable and consistent signal interpretation can be obtained by ensuring that sensors with a suitable sensing mechanism are selected based on operational demands, and that materials used within the sensors do not change structurally under vacuum and expected applied pressures, and between temperatures of -80°C to +120°C. The sensors must be able to withstand space environmental conditions and remain adequately sensitive throughout their operating life. Additionally, it is necessary to integrate the sensors into the target system with minimum disturbance while remaining responsive to applied loads. Previous work has been completed to characterize sensors within the selected temperature and pressure ranges. The current work builds on this investigation by embedding these sensors in different geometries and testing the response measured among varying configurations. Embedding material selection was aided by using a dynamic mechanical analyzer (DMA) to determine stress/strain behavior for adhesives and compliant layers used to keep the sensors in place and distribute stresses evenly. Electromechanical characterization of the embedded sensor packages was conducted by using the DMA in tandem with an inductance-capacitance-resistance (LCR) meter. Methods for embedding the sensor packages were developed with the aid of finite element analysis and physical testing to account for specific geometrical constraints. Embedded sensor prototypes were tested within representative models of potential embedding locations to compare final embedded sensor performance.

Forest Biomass Utilization for Biofuels and Bioproducts

1 Wood Science and Technology, Division of Forestry and Natural Resources, West Virginia University, Morgantown, WV 26505, USA 2 Forest Ecology and Hydrology, Chinese Academy of Forestry, Beijing 100091, China 3 Forest Operations, School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL 36849-5418, USA 4 Institute of Product Design and Manufacturing, University of West Hungary, Sopron, Hungary