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Cellulose nanofibril (CNF) films currently provide great opportunity in many applications with advantages of excellent mechanical strength, high light transmittance, and good barrier properties. However, processes for preparing CNFs are typically tedious and vary, along with their properties. Here, five preparation methods using various combinations of filtration, freeze-drying, and casting are applied to produce CNF films, and their major properties are compared. Three different types of CNFs having a range of fiber diameter and aspect ratio were examined using each of these five preparati...

Fiber-reinforced polymer composites have gained popularity through their advantages over conventional metallic materials. Most polymer composites are traditionally made with reinforcing fibers such as carbon or glass. However, there has been recent interest in sourcing these reinforcing fibers from renewable, natural resources. Nanocellulose-based reinforcements constitute a new class of these naturally sourced reinforcements. Some unique behavior of nanocellulose creates both opportunities and challenges. This chapter reviews the progress and some of the remaining issues related to the...

Methods to increase the energy density of biofuel feedstock for shipment are important towards improving supply chain efficiency in upstream processes. Towards this end, densified pretreated lignocellulosic biomass was produced using hot-pressing. The effects of fiber hornification induced by hot-pressing on enzymatic digestibilities of lodgepolepine and poplar NE222 wood chips pretreated by sulfite pretreatment to overcome recalcitrance of lignocelluloses (SPORL) were examined. Pretreated wood chips were pressed at 25, 70, 90, 110, and 177 °C. The cellulose accessibilities of the pressed...

Cellulose nanocrystals (CNCs), a class of renewable bionanomaterials with excellent mechanical properties, have gained major interest as filler for polymers. However, challenges associated with effective CNC dispersion have hindered the production of composites with desired property enhancements. Here, composites of polypropylene (PP) and low density polyethylene (LDPE) with 5e10 wt% unmodified CNC are produced for the first time via a solventless process. In particular, we employ solid-state shear pulverization (SSSP). Optical and electron microscopy reveals excellent CNC dispersion with...

This report presents forecasts from the Southern Forest Futures Project that are specific to the Mid-South, which consists of four sections located within Arkansas, Oklahoma, and Texas: the Ozark-Ouachita Highlands, the Cross Timbers, the High Plains, and the West Texas Basin and Range. Ranging from Little Rock, AR to El Paso, TX, it is the most diverse subregion in the South. The Mid-South faces a number of important challenges to management of forests and woodlands over the next 50 years, including population increases, the likelihood for increased drought, increased demand for water and...

Biological invasions are one of the most significant global-scale problems caused by human activities. Earthworms function as ecosystem engineers in soil ecosystems because their feeding and burrowing activities fundamentally change the physical and biological characteristics of the soils they inhabit. As a result of this “engineering,” earthworm invasions can have significant effects on soil physical, chemical and biological properties. The species Amynthas agrestis (family Megascolecidae) was introduced to the United States from Asia, and has expanded its distribution range to include...

Este informe presenta los resultados del cuarto inventario forestal de las islas del Estado Libre Asociado de Puerto Rico. El área de bosque en la isla grande de Puerto Rico se mantuvo constante o aumentó ligeramente del año 2004 al 2009. Este cambio parece indicar que la tasa de incremento de cubierta forestal en la isla grande de Puerto Rico ha disminuido desde que el inventario forestal comenzó en 1980. Tanto Culebra como Vieques pudieron haber experimentado una pérdida leve en cubierta forestal. Sin embargo, los errores de muestreo son lo suficientemente amplios como para abarcar estos...

Documenting the environmental performance of building products is becoming widespread because of many green marketing claims made without scientific merit (i.e., green-washing). Developing environmental product declarations (EPDs) for building products is one way to accomplish this objective for scientific documentation and to counter green-washing (ISO 2006a; Bergman and Taylor 2011). LCI data are the underlying data for subsequent development of LCIAs and EPDs. EPDs are similar to nutritional labels for food. At present, there are many EPDs for North American structural wood products...

There is a growing demand for material properties to be used as inputs in fi re behavior models designed to address building fire safety. This comparative study evaluates using the mass loss calorimeter as an alternative to the cone calorimeter for obtaining heat release rates of wood-based materials. For this study, a modified mass loss calorimeter utilized an improved heat release rates method that added four thermocouples install ed on a chimney wall above the coni cal heater in addition to the standard air them1opile at the chimney top. The cone calorimeter used the standard oxygen...

Verifying national greenhouse gas (GHG) emissions inventories is a critical step to ensure that reported emissions data to the United Nations Framework Convention on Climate Change (UNFCCC) are accurate and representative of a country's contribution to GHG concentrations in the atmosphere. Furthermore, verifying biogenic fluxes provides a check on estimated emissions associated with managing lands for carbon sequestration and other activities, which often have large uncertainties. We report here on the challenges and results associatedwith a case study using atmospheric measurements of CO2...