Bonding of densified beech wood using adhesives based on thermally modified soy proteins

The bondability/glueability of aged and sanded thermo-hydro-mechanically (THM) densified beech wood (Fagus sylvatica L.) was tested and compared with undensified sanded beech wood as a control. THM and control specimens were bonded with five different soy protein isolate (SPI) based adhesives. Commercial SPI powder was thermally modified in the vacuum chamber at 50 or 100?°C and pH adjusted (to pH 10.0) dispersions in water prepared at 24, 50 or 90?°C. Wettability was determined with measuring the sessile drop contact angles of water. Effective penetrations (EPs) and tensile shear strengths of THM and control specimens were determined. THM and control wood had similar wettability. Although THM wood had lower moisture content than control wood, it absorbed the water more slowly than control wood. THM specimens showed lower EPs than control specimens when comparing individual adhesives due to increased density of THM wood. Adhesives prepared with SPI thermally modified at 50?°C showed statistically significantly lower tensile shear strength of bonded THM specimens than that of bonded control specimens. THM densification had no significant effect on the bonding strengths of adhesives prepared with non-modified SPI and SPI thermally modified at 100?°C.     

Globally stabilizing control of fed-batch processes with Haldane kinetics using growth rate estimation feedback

The regulation of the biomass specific growth rate is an important goal in many biotechnological applications. To achieve this goal in fed-batch processes, several control strategies have been developed employing a closed loop version of the exponential feeding law, an estimation of the controlled variable and some error feedback term. In the case of non-monotonic kinetics, the specified growth rate can be achieved at two different substrate concentration values. Because of the inherent unstable properties of the system in the decreasing portion of the kinetics function, stabilization becomes a crucial problem in this high-substrate operating region. In this context, the dynamic behavior of fed-batch processes with Haldane kinetics is further investigated. In particular, some conditions for global stability and performance improvement are derived. Then, a stabilizing control law based on a partial state feedback with gain dependent on the output error feedback and gain saturation is proposed. Although particular emphasis is put on the critical case of high-substrate operation, low-substrate regulation is also treated.     

Mass Transfer In Trickle‐Bed Reactors With Structured Packing

An experimental investigation was carried out to examine the fluid dynamic and mass transfer behavior of structured packing, with the liquid and gas phase flowing co‐currently downwards in the column. Liquid to packing mass transfer coefficients for three positions within the pack were measured by an electrochemical method, varying both the liquid and gas loads as well as the physical properties of the liquid phase. Due to the high void fraction of structured packing, much higher liquid flow rates can be used than in traditional particle trickle‐beds. It was found that in the range studied, the gas superficial velocity has no effect on the mass transfer rate and thus, a general mass transfer correlation in terms of liquid Reynolds number only, was developed. Wetted areas and the radial distribution of liquid through the packing element were determined by a colorimetric method. Within the range of liquid flow rates investigated, complete wetting is not achieved, even with the low viscosity solutions. The measured ratios of hydraulic to geometric area, agree reasonably well with values predicted by existing relationships.     

Enhancing IEEE 802.11p/WAVE to provide infotainment applications in VANETs

IEEE 802.11p/WAVE (Wireless Access for Vehicular Environment) is the emerging standard to enable wireless access in the vehicular environment. Most of the research contributions in this area has focused on safety-related applications, while comfort and information/entertainment applications (such as on board Internet access, point-of-interest notification, e-map download) have been considered only recently. Notwithstanding, the user interest in this kind of applications is expected to become a big market driver in a near future. In this paper, an extension to IEEE 802.11p is proposed that is compliant with the multi-channel operation of the WAVE architecture and targets at the support of non-safety applications, while preserving the delivery of safety services. The proposed W-HCF (WAVE-based Hybrid Coordination Function) protocol leverages controlled access capabilities on top of the basic contention-based access of the IEEE 802.11p; it exploits vehicles’ position information and coordination among WAVE providers in order to improve performances of delay-constrained and loss-sensitive non-safety applications.     

Effect of different fermentation parameters on l-lactic acid production from liquid distillery stillage

Expansion of lactic acid applications, predominantly for the preparation of biodegradable polymers increased the research interest for new, economically favourable production processes. Liquid stillage from bioethanol production can be an inexpensive, valuable source of nutrients for growth of lactic acid bacteria. Utilisation of residual biomass with spent fermentation media as a functional animal feed can greatly influence the process value and its ecological aspect. In this paper, the kinetics of lactic acid and biomass production on liquid stillage by Lactobacillus rhamnosus ATCC 7469 was studied. In addition, the impact of temperature, inoculum concentration, shaking and pH control by addition of CaCO₃ was evaluated. Maximal lactic acid yield of 73.4%, as well as high biomass production (3 × 10⁸ CFU ml⁻¹) were achieved under selected conditions (41 °C, 5% (v/v) of inoculum, 1% (w/v) of CaCO₃, initial pH of 6.5 and shaking rate of 90 rpm). These results were achieved without supplementation of the stillage with nitrogen or mineral sources.     

Core − shell microgels with controlled structural properties

Microgels have gained great attention in the biomedical field for their wide application in diagnostic and drug delivery systems. The bulk properties as well as the surface features of these particular microparticles define their final performance. In particular, multifunctional microgels with complex architectures have been widely used in multiplex assays for their favourable capability to accommodate encoding systems and anchoring groups for probes to capture circulating targets by simply changing synthesis parameters. In this work a limited set of fluorescent encoded poly(ethyleneglycol) based microgels, of size ranging between 0.5 and 1.3 µm, with a core ? shell architecture were obtained by combining precipitation and seeded polymerizations. Here we demonstrate the possibility of tailoring and controlling the bulk and surface properties according to the synthesis by fluorescence imaging and pH titrations. Concerning the structural characterization, we adopted a method to calculate polymer fraction volumes from AFM images and combined these with equilibrium swelling theory (Peppas–Merrill equation) to determine the mesh size of the microgels. Surface composition was probed by X‐ray photoelectron spectroscopy directly on freeze‐dried microgels. In such a way we were able to describe the organizations of the different adlayers also in response to pH, highlighting the possibility of some overlap of the adlayers representing physical barriers at the boundaries of each shell. © 2016 Society of Chemical Industry     

Degradation and early in vitro activity of healthy hepatocytes onto bicomponent electrospun fibers

Bicomponent electrospun fibers (BEFs) have been designed as building blocks of various biomedical devices, i.e., scaffolds, conduits, grafts, for the repair/regeneration of in vitro and in vivo tissues. With respect to monocomponent fibers, BEF may exert diversified patterns of signals—morphological, chemical or physical—confined at the single fiber level, conferring them a unique ability of self-adapting to local microenvironment and influencing cell/fiber interaction. Herein, an investigation of basic relationships between degradation properties of BEF and in vitro response of healthy hepatocytes to prove their use as in vitro model to predict in vivo liver regeneration is proposed.     

Optimal gain-scheduled control of fixed-speed active stall wind turbines

For a smooth integration of large wind farms into the utility grids, the individual wind turbines must be able to achieve various power control objectives. In this context, the authors focus their attention on the control of fixed-speed active stall wind turbines. This sort of turbine includes a pitch servomechanism to induce stall on the blades, thereby having control on the output power. The authors develop a methodology to design optimal gain-scheduled pitch controllers valid for the whole operating region of the wind turbine. The proposed solution uses concepts of linear parameter-varying system theory. In addition to providing a formal framework for the control design, this theory guarantees stability and performance. Further, because of the similarities with Hαcontrol, the tools developed for the controller design are very familiar to the control community. The main features of the proposed controller are assessed by means of numerical simulations obtained for realistic wind speed profiles and power production demands.     

Hydrogen production from idle generation capacity of wind turbines

This paper is concerned with the hydrogen production from wind energy. It is motivated by the new regulations for wind farms that compel them to operate normally with idle generation capacity. The idea is to use the excess wind power to produce hydrogen. The operation of a proposed system configuration, which essentially consists in incorporating an electrolyzer between the electronic converters of a conventional wind turbine, is analyzed. In particular, the control requirements to simultaneously achieve the grid and electrolyzer specifications are investigated. In this context, a control strategy for the different operating modes of the system is developed.