Volume 12 Issue 2

Biomaterials and new processes (3D printing and flexible hybrid electronics) offer opportunities to break free from a 2D paper world by allowing for the development of smart multi-dimensional structures. While there has been recent progress reported in each of these areas of technology, to date, the merger of these technologies has been very limited. We believe that their merger offers boundless opportunities and an opportunity for the paper industry to innovate a low cost, sustainable housing solution capable of promoting the well-being of its occupants while minimizing the environmental impact of its daily use.

A communications scholar at our university asked me recently whether I would take part in a debate about academic social media services such as ResearchGate. Yes, I responded, as long as I don’t have to argue the affirmative – that such online systems are necessarily a good thing. Personally I do not count myself as a user of academic social media, but I can easily understand why others could make an opposite decision. Academic social media can provide a way to get copies of full-length published articles, to pose questions to other researchers, to get various questions answered, and in general to foster relationships with well-networked and possibly influential people within one’s academic field. Or, like me, you might just enjoy having something mildly annoying that is fun to complain about.

The impact of veneer punching pattern and density (343, 356, and 1424 hole·m-2) was tested relative to selected physic-mechanical properties of 5-ply laminated veneer lumber (LVL) panels fabricated from poplar wood (Populus deltoides) under different press time (5, 6, and 7 min). Samples were made with urea-formaldehyde resin using hot press technology at a uniform pressure of 10.8 N·mm-2 and temperature of 120 °C. The results indicated that punching the inner veneers (except the core veneer) of LVL significantly improved the average values of shear strength, modulus of elasticity, and bending strength (both parallel and perpendicular to the grain). In contrast to control samples, the veneer punching technique showed an overall negative impact on the water resistance of LVL (after either 2 or 24 h of immersion in water). Nevertheless, specimens with punching densities of 1424 hole·m-2 pressed for a maximum of 5 min were more dimensionally stable than the control samples. The physic-mechanical properties of LVL were significantly affected by presstime as well. Considering the data obtained, the presstime of LVL could be reduced to nearly 16.7%, or 1 min, by using a punching density of 1424 hole·m-2 without any significant negative change in the major physic-mechanical properties.

The objective of this study was to evaluate the mechanical properties of ancient wood of Abies fabri (Mast.) Craib based on the nondestructive tests and reliability analysis. Nondestructive tests including resistograph and stress wave test, and destructive tests were conducted on the wood specimens. Results indicated that there were significant linear correlations between the resistance amplitude (F) and green density (ρ), the dynamic modulus of elasticity (ED) and static modulus of elasticity (MOE), modulus of rupture (MOR), and ultimate compressive strength (UCS) of wood specimens. The cumulative distribution of the predicted MOR and UCS based on the nondestructive tests could be well fitted by the normal distribution according to the χ2 test. Moreover, a reliability analysis program based on the first-order second-moment method was developed. Reliability analysis results showed that the reliability index increased nonlinearly with the increase of the live-to-dead load ratio, and decreased nonlinearly with the increase of the design values for all the simulation load cases. According to the minimum reliability index requirements of the Chinese national standard, it is suggested that the design value of MOR and UCS be 14.0 and 10.7 MPa, respectively.

To obtain a higher furfural yield from Pisum sativum (pea pod) waste, the effects of the process variables phosphoric acid concentration (wt.%), reaction temperature, and liquid solid ratio (LSR) were investigated. A new reaction scheme was proposed consisting of series and parallel reactions for the formation of furfural. Kinetic models were developed to describe changes in the concentration of furfural with time. A modified Arrhenius equation was used to find out correlations between kinetic coefficients and reaction parameters. A maximum furfural concentration of 5.27 g/L (40.6% yield based on total conversion of pentosans) was obtained using 6% (wt.%) H3PO4 and liquid-to-solid ratio of 1:10 at 160 °C. Reaction parameters such as acid concentration, reaction temperature, and liquid solid ratio had a strong effect on the yield of furfural.

Cork is one of the most important forest products in Portugal. The cork processing industry is highly resource-efficient, and the only residue is cork powder, which is too small for agglomerate production. This work studied the usage of cork powder for the production of added-value products via polyol liquefaction. Liquefactions were performed in a reactor using a mixture of polyethylene glycol (PEG 400) and glycerol as solvents, which were catalyzed by the addition of sulphuric acid. Several cork-to-solvent ratios, reaction temperatures, and reaction times were tested. Polyurethane foams were prepared by combining polyol mixtures with a catalyst, surfactant, blowing agent, and polymeric isocyanate. Mechanical tests of the produced foams were conducted, and compressive modulus of elasticity and compressive stress at 10% deformation were determined. The results show that the best conditions for obtaining high liquefaction yields are as follows: 160 °C for 1 h; glycerol-to-PEG 400 ratio of 1:9; cork-to-solvent ratio of 1:6; and 3% H2SO4 catalyst addition. The Fourier Transform Infrared (FTIR) spectra indicated that the lignocellulosic fractions of the cork were more selectively dissolved during acidified polyol liquefaction than the suberin. With liquefied cork powder using these optimized conditions, it is possible to produce polyurethane foams with desired properties.

A graphene/hemin (H-GN) catalyst for lignin degradation was prepared by a wet-chemistry method with graphene oxide and hemin. Hemin was absorbed onto the graphene surface through π-π interaction. Graphene served as a supporting material for hemin, providing a large contact area between the active molecules of catalyst and substrate, as well as protecting hemin from self-oxidation and maintaining its active molecules. The H-GN catalyst showed high catalytic efficiency in the degradation of alkaline lignin under gentle conditions. At pH 13.0, the degradation rate was 49.7% with H-GN and H2O2 (mass ratio of H2O2 to lignin of 10:1) under 60 °C, which was higher than 34.9% for non-catalyst degradation. At pH 13.2, it was as high as 92.9 wt.% at 100 °C. The lignin was decomposed into small molecules with styrene as the main final product below pH 13 and with the major products of 4-hydroxy-4-methyl-2-pentanone and bis(2-ethylhexyl) phthalate at pH 13.2.