Treesearch

To improve the conversion of enzymatic hydrolysis of biomass in an energy-efficient manner, two shorttime ultrasonication strategies were applied on six types of biomass with different structures and components. The strategies include pre-sonication before the hydrolysis and intermittent sonication during the ongoing hydrolysis. The microstructures of each type of biomass were characterized by scanning electron microscopy to investigate the potential correlation between biomass structure and ultrasonicaton. The concentration of resultant reducing sugar was measured to evaluate the efficienc...

Wood char,a by-product from the fast-pyrolysis process of southern yellow pine wood for bio-oil production, was carbonized with Fenano particles (FeNPs) as a catalyst to prepare carbon-encapsulated Fe nanoparticles. A magnetic separation method was tested to isolate carbon-encapsulated Fe nano particles from the carbonized char. X-ray diffraction pattern clearly shows that Fe-containing materials were completely separated from the carbonized wood char mixture using a magnet. The amorphous carbon in the material which adhered to the magnetic bar was significantly decreased in comparison...

Sodium lignosulfonate (LS) from sulfite pulping processing was used as a carbon source to synthesize graphene. LS was mixed with Fe nanoparticles (FeNPs) as a catalyst and thermally treated at 1000 °C for 1 h. The Raman spectrum and X-ray diffraction pattern suggested that graphene sheets were formed in LS thermally treated with FeNPs (Fe-HTLS). Scanning electron microscopy image of Fe-HTLS showed clusters of thin graphene sheets appearing in the form of nanoflowers. High-resolution transmission electron microscopy and electron reflection images provided further evidence of the formation...

A glulam beam is subjected to X-ray computer tomography and acousto-ultrasonic measurements to detect and assess wood decay. A glulam beam without visible indications of wood decay was taken from field use. A modified impulse-echo technique is employed as an inspection method requiring access to only one side of the beam. It is observed that decay-rate analysis of the collected signals allows detection and assessment of wood decay. The decay-rate approach leads to an overall rate of false calls of 7.2%. Considering the variability that exists in wood including the presence of splits,...

Soft-story woodframe buildings are recognizable by their large garage openings at the bottom story which are typically for parking and storage. In soft-story buildings the relative stiffness and strength of the soft-story, usually the bottom story, is significantly less than the upper stories due to the presence of large openings which reduce the available space for lateral force resisting system com-ponents such as shearwalls. This leads to large inter-story drifts and potential collapse at the ground floor, be-fore the upper stories inter-story experience significant drifts. In many...

Giant reed was evaluated for enzymatic hydrolysis and simultaneous saccharification and fermentation(SSF) using a commercial cellulase/β-glucosidase and Scheffersomyces (Pichia) stipitis CBS 6054 for ethanolproduction following dilute-oxalic acid pretreatment. A response surface methodology with two inputparameters – severity factor (SF) and oxalic acid concentration (OA) – was employed to optimize bothenzymatic hydrolysis and SSF. Xylan content after dilute-OA pretreatment decreased with increasingSF and OA; almost complete hydrolysis was observed when the harsher pretreatment conditions...

To degrade the polysaccharides, wood-decay fungi secrete a variety of glycoside hydrolases (GHs) and carbohydrate esterases (CEs) classified into various sequence-based families of carbohydrate-active enzymes (CAZys) and their appended carbohydrate-binding modules (CBM). Oxidative enzymes, such as cellobiose dehydrogenase (CDH) and lytic polysaccharide monooxygenase (LPMO, formerly GH61), also have been implicated in cellulose degradation. To examine polysaccharide-degrading potential between white- and brown-rot fungi, we performed genomewide analysis of CAZys and these oxidative enzymes...

The objectives of this study were to investigate the influence of cross sectional size and moisture content on stress wave properties of structural timber in various sizes and evaluate the feasibility of using stress wave method to E-rate timber in green conditions. Four different sizes of Douglas-fir (Pseudotsuga menziesii) square timbers were tested using both stress wave and static bending methods at different moisture levels, ranging from green to dry conditions. As expected, stress wave velocity increased continuously as moisture content decreased through the whole moisture range...

Invoking normal adhesion theory, bonding of wood would seem to be easy in that the surface has plenty of roughness for mechanical interlocking with high enough surface energy, there is an abundance of hydroxyl groups on the wood for hydrogen bonding to the adhesives, and the aqueous solvent in the adhesive can readily soak into the wood. In fact most adhesives will form good to excellent bonds to wood as long as the bond is kept dry. However, because wood swells and shrinks with changes in ambient relative humidity, most bonded wood products must pass some type of moisture exposure test....

The existence of thousands of soft-story woodframe buildings in California has been recognized as a disaster preparedness problem with concerted mitigation efforts underway in many cities throughout the state. The vast majority of those efforts are based on numerical modeling, often with half-century old data in which assumptions have to be made based on best engineering judgment and project committee consensus. The NEES-Soft project, whose full title is “Seismic Risk Reduction for Soft-Story Woodframe Buildings,” is a five university multi-industry three-year project which has many facets...