Volume 14 Issue 3

Foams are encountered in everyday life across wide applications, e.g., in foods and cleaning products. They have also been widely used in different industries in processes such as flotation and oil recovery. The application of bio-based materials is a novel interest, and foam forming enables these materials to be used more flexibly. For efficient industrial usage, the flow of such materials must be well understood and characterized. This work measured the velocity field of nanocellulose laden foam in a two-dimensional Hele-Shaw cell with a constriction, using optical imaging and particle image velocimetry. The measurements showed that the addition of cellulose increased the effective viscosity of the liquid films. In a numerical simulation using the Giesekus polymer model, the experimental trend was reproduced through increasing the fluid’s viscosity. Adding highly viscoelastic nanofibrillated cellulose suspension to foam affected only the viscous component of the foam. The delayed elastic response did not change.

Vessel and fiber properties, diameter growth, and chemical compositions were investigated for transgenic Populus trichocarpa (black cottonwood) trees harvested after six months of growth in a greenhouse. Genetic modifications were cinnamyl alcohol dehydrogenase (CAD), cinnamate 3-hydroxylase (C3H), or cinnamate 4-hydroxylase (C4H), which resulted in modified lignin composition or content, and changed the syringyl-to-guaiacyl ratio. Comparing the genetic groups to the wild-type as the control, trees with reduced lignin content showed different results for vessel and fiber properties measured. Genetic groups with reduced PtrC3H3 and PtrC4H1&2 (with lower lignin content and higher S/G ratio than the control) exhibited splitting perpendicular to the rays, yet had the same fiber lumen diameter and the same fiber cell wall thickness as the control. Changes in lignin structure from modifications to PtrCAD resulted in reductions to the number of vessels, increases in vessel and fiber diameters, and had no consistent impact on stem diameter.

The effect of end distance was evaluated relative to the static ultimate lateral resistance load of single-shear unconstrained metal-to-parallel bamboo strand panel (PBSP) single-bolt connections that failed in end tear-out, net cross-section tension modes. Empirical equations for estimation of the static ultimate lateral resistance loads of the evaluated connections were derived. The connection consisted of a PBSP main member fastened to a metal plate as a side member using a 6 mm diameter bolt without a nut or washer. The stress concentration factor was considered in the process of deriving the estimation equations for static ultimate lateral resistance loads. The experimental results indicated that the stress concentration factor was a linear function of end-distance to bolt-diameter ratio, (e/d), for connections that failed in end tear-out mode, while a quadratic function of (e/d) for connections that failed in net cross-section tension mode. The derived estimation equations including stress concentration factor can reasonably estimate the static ultimate lateral resistance load of single-shear unconstrained metal-to-PBSP single-bolt connections evaluated in this study.

Lignocellulose nanofibrils (LCNFs) were prepared using Liriodendron tulipifera L. wood flour. Electrospun nanofibers were fabricated by mixing the LCNFs with poly(vinyl alcohol) (PVOH). The lignin and hemicellulose contents of the wood flour were controlled with an alkaline-peroxide treatment at a pH of 11.5 using various hydrogen peroxide concentrations. The morphological characteristics, mean diameter, and filtration time of the LCNFs subjected to wet disk milling (WDM) and high-pressure homogenization were determined. Furthermore, the spinning suspension viscosity was measured with various LCNF concentrations and PVOH/LCNF addition ratios. After the alkaline-peroxide treatment, the lignin and hemicellulose contents decreased with an increasing hydrogen peroxide concentration and reaction time. As the lignin content decreased, the nanofibril diameter decreased and the filtration time increased. The diameter decreased further after the homogenization treatment following WDM. The viscosity of the mixed solution increased with an increasing PVOH and LCNF mixed solution concentration and LCNF addition ratio, and decreasing lignin content. Scanning electron micrographs revealed that the diameter of the electrospun nanofibers increased as the mixed solution concentration and LCNFs addition increased, the lignin content decreased, and with the homogenization treatment.

Wooden components were removed from ancient buildings and used as experimental materials. The drilling curve and feed curve were generated from data collected by a resistograph, and the wood density was predicted by using the information diffusion model. A significant correlation was observed between the data for micro-drilling resistance and wood density. The information diffusion methodology was able to predict the wood density by the nonlinear method very well. Using the two-curve effect weight, when the drilling curve data and the feed curve data were 0.2 and 0.8, respectively, the error was minimum, with an average relative error of 3.82%. Therefore, the data supported on-site ancient building repair work.

Judicial utilization of various low-cost agro-industrial wastes and optimization of various process parameters can reduce production costs of enzymes. Wheat bran was found to be the best carbon source among various agro-industrial wastes explored for Penicillium citrinum NCIM-1398. Additionally, ammonium sulphate was found as the optimum nitrogen source at moisture content 70%, pH 5.5, and temperature 30 °C for enzyme production. The maximal enzyme activities of endo β-1,4-glucanase, xylanase, FPase, and amylase were 21.0 IU/gds, 3140 IU/gds, 3.59 FPU/gds, and 73.4 IU/gds, respectively. Bio-deinking of mixed office waste paper improved the pulp brightness by 9.5%, and the effective residual ink concentration were decreased by 26.3% in comparison to MOW after pulping. Similarly, dirt counts were reduced from 4880 to1360 ppm at an enzyme dose of 6.0 IU/g compared to deinking without enzyme. The strength properties of enzymatically deinked pulp such as tear index, tensile index, and burst index increased by 6.92%, 11.31%, and 7.61%, respectively, compared with the control.

Larch bark is an undervalued material, but it has unique and valuable characteristics and compounds. The objective of this study was to extract and characterize molecular compounds of bark materials from different larch trees and to test these for their antimicrobial properties. The extractions were performed using methanol or water. The obtained extracts were analysed by gas chromatography coupled to mass spectrometry (GC-MS). Antimicrobial properties also were determined using different microbial strains, for example, Staphylococcus aureus. The GC-MS analysis showed that long chain alcohols, fatty acids, and polyphenols were present in the extracts. According to the results of the agar diffusion tests, only the methanol extract of larch bark had an inhibitory effect on the growth of Staphylococcus aureus. Two compounds of flavonoids and stilbenoids were shown to affect the microbial activity of the larch bark. Therefore, larch bark can be used for the extraction of compounds with specific anti-microbial properties.

Catalytic fast pyrolysis of hemicellulose with zeolite catalysts is a promising method to produce aromatic hydrocarbons (Carlson et al. 2009). In this paper, the behavior of hemicellulose catalytic pyrolysis with HZSM-5 (with three different silica to alumina ratio, 23, 50, 80), HY, and Hβ was studied. Pyrolysis vapor was separated into non-condensable vapors and condensable fractions. The fractions were qualified and quantified by a gas chromatography / flame ionization detector (GC/FID) system and a gas chromatography / mass spectrometer (GC/MS) system, respectively. The influences of catalysts and pyrolysis parameters were studied. Among the catalysts, HZSM-5(23) provided the desired acidity and shape selectivity for aromatic hydrocarbon production. A higher catalyst to hemicellulose ratio (CHR) and higher heating rate resulted in a higher aromatic hydrocarbon yield. The most suitable pyrolysis temperature for hemicellulose with HZSM-5 was 650 °C. During catalytic pyrolysis, thermal decomposition products underwent deoxygenation reactions promoted by the acid sites on the zeolite. The C2-C4 deoxygenated products produced monocyclic aromatic hydrocarbons (MAH) by shape-selective catalysis reactions in zeolite pores. With higher temperatures and higher residence times, monocyclic aromatic hydrocarbons facilitated cyclization reactions with C2-C4 deoxygenated products, thereby forming polycyclic aromatic hydrocarbons (PAH).

Isolation and characterization of solventogenic bacteria from animal feces were carried out. Ten samples were collected continually for 5 d from the feces of wild rabbit and wild swine in Jawaharlal Nehru Zoological Park, Hyderabad, India. Ten acetone-positive strains were selected for evaluation of their phenotypic and physiological characteristics. Two potential solvent-producing cultures were selected for 16S rRNA gene analysis. The culture isolated from the wild rabbit feces exhibited 97.3% similarity with Clostridium beijerinckii 8052, and the culture isolated from the wild swine feces exhibited 93.8% similarity with Clostridium saccharoperbutylacetonicum NI-4(HMT). The isolated strains utilized a wide range of carbohydrate substrates including glucose, fructose, maltose, xylose, arabinose, and glycerol. The major fermentation products from glucose, xylose, and arabinose were acetone, butanol, and ethanol (ABE). The total ABE concentration produced by strain YVU1 was 13.1 g/L from arabinose, 16.3 g/L from xylose, and 20.6 g/L from glucose. Strain YVU2 produced a total ABE concentration of 16.5 g/L, 18.3 g/L, and 22.4 g/L from arabinose, xylose, and glucose, respectively.

Aerobic granules are large, compact microbial aggregates when compared to flocculent sludge, and they can be used in wastewater treatment. The application of aerobic granular sludge in bioreactors for the treatment of industrial effluents is still considered innovative and has been the subject of several recent studies. In the present study, 19 microbial isolates from mesophilic aerobic granules, obtained from a previous study, were evaluated in co-aggregation tests. The extracellular polymeric substances (EPS) produced, such as carbohydrates, proteins, and humic acids, were determined. The aim was to evaluate the relationship between the amount of EPS produced and the contribution of each isolate in the granulation process. The results of EPS production were used to analyze the polysaccharide / protein (PS / PN) ratio. The consortia with an absence of isolates 4, 8, 11, 14, 19, and 25 presented a PS / PN ratio <0.5. These isolates, identified as belonging to the genera Staphylococcus, Agrobacterium, Enterobacter, and Rhodococcus, were considered effective for the production and stability of the mesophilic aerobic granules.