Treesearch

Preparing cellulose II nanocrystals (CNC II) requires a polymorph transformation of natural cellulose I feedstocks. The transformation is usually achieved via a process such as mercerization or dissolution– regeneration. This study demonstrated a new method to prepare CNC II directly from bleached kraft pulp (BKP, a commercially available cellulose I feedstock) in a mildly acidic lithium bromide trihydrate (MALBTH) system, a concentrated (∼61 wt%) solution of LiBr in water with a very low concentration (2.5 mM) of sulfuric acid. First, the BKP was treated in the MALBTH system to generate a...

Carboxylated cellulose nanocrystals (CNCs) were produced from cotton linter using a mixture of a dicarboxylic acid (maleic acid or succinic acid) and its corresponding anhydride with or without catalyst in acetic acid as solvent. The low solubilities of these dicarboxylic acids can ease chemical recovery and decrease environmental impact (especailly maleic acid is a U.S. FDA approved indirect food additive (21CFR175-177)) and capital costs compared with the conventional concentrated sulfuric acid hydrolysis for producing CNCs. The dicarboxylicacid-produced CNCs (DC-CNCs) contained surface...

Coupled fire-atmosphere models are increasingly being used to study low-intensity fires, such as those that are used in prescribed fire applications. Thus, the need arises to evaluate these models for their ability to accurately represent fire spread in marginal burning conditions. In this study, wind and fuel data collected during the Prescribed Fire Combustion and Atmospheric Dynamics Research Experiments (RxCADRE) fire campaign were used to generate initial and boundary conditions for coupled fire-atmosphere simulations. We present a novel method to obtain fuels representation at the...

A naturally occurring smart mycelium surface with tunable wettability is demonstrated. The commercially produced mycelium foam shows a natural hydrophobic and nonabsorbent surface with water contact angles well above 135°. The surface maintains its hydrophobicity and nonabsorbance after being compressed into a thin film under pressure and mild temperatures. We report that this surface carries tunable wettability. We have shown that a facile water treatment followed by room-temperature drying initially renders the surface highly hydrophilic and absorbent. Subsequent conditioning at 50 °C at...

The standard for calculating grade quality index (GQI) is a three-step process. First, failure codes are assigned during testing. Second, strength ratios are calculated from failure codes recorded during post-test analysis, not including failure from slope of grain. Third, the lower fifth percentile strength ratio is identified, which is defined as the GQI. In the past, the process of calculating strength ratios required one to correctly interpret and apply calculations per ASTM D4761 (current edition) and ASTM D245 (current edition) or gain remote access to USDA Forest Service, Forest...

February housing data indicated moderation in the U.S. housing market. Month-over-month data were mostly mixed; year-over-year data were predominantly positive, with the exceptions of total housing starts, multifamily starts, and multifamily housing under construction. New single-family and existing house sales were negative month-over-month and positive year-over-year. Single-family construction spending was positive month-over-month and year-over-year.

Vacuum kiln-drying, using low temperature in a low oxygen environment, produces light-colored hard maple in a significantly shorter drying time, and with less variability, than does conventional steam kiln-drying. To avoid chemical staining and to maintain light color, drying hard maple requires the use of high air flow at low temperature and relative humidity soon after being sawn. This study compared the color and drying times of hard maple dried in both types of kilns. Paired samples of 1-in. (25.4-mm) flat-sawn boards were dried in either a conventional kiln or a vacuum kiln, and...

Cross-laminated timber (CLT) is a mass timber product that has recently garnered considerable attention for lateral-force resisting system (LFRS) applications. The main objectives of this study were to investigate the rocking behavior of a high-aspect-ratio (height/width) CLT shear wall without post-tensioning, and to validate a finite-element (FE) model based on the cyclic and dynamic response of the wall. To this point, high-aspect-ratio walls in the literature have primarily been post-tensioned. The testing component of this study included connector tests, quasistatic cyclic shear wall...

The potential of neat poly(lactic acid) (PLA) and PLA/cellulose nanocrystal (CNC) blown films in extending the shelf-life of crackers, a moisture-sensitive food product, was assessed. Product’s shelf-life, i.e., the time required by the crackers to reach its critical moisture content (CMC) of 8%, was determined experimentally from moisture content versus storage time plots at a constant temperature (25 °C) and various conditions of relative humidity (RH). Neither crackers within PLA nor PLA/CNC packages reached the CMC when stored below 50% RH at 25 °C, indicating that crackers packaged in...

The yeast Schwanniomyces polymorphus is associated with the infrabuccal pocket in the carpenter ant Camponotus vicinus (Hymenoptera: Formicidae), but its role in ant development is poorly defned. The potential effects of this yeast on brood development were examined on sets of larval groups and workers over a 12 week period. Worker–larval sets were fed variations of a completely artifcial, holidic diet and exposed or not exposed to live S. polymorphus. Worker–larval sets in half of the experiment were defaunated using a two-step heat and chemical process. Brood development and number of...