The Hydraulic Power Generation and Transmission on Agricultural Tractors: Feasible architectures to reduce dissipation and fuel consumption-Part i

This paper is aimed at investigating the benefits in terms of energy efficiency of new electro-hydraulic architectures for power distribution systems of a medium-size agricultural tractor, with a focus on the hydraulic high-pressure circuit. The work is part of a wider industrial research project called TASC (Smart and Clean Agricultural Tractors [1]). Traditional and alternative architectures have been modelled and energetically compared through simulation, using a lumped parameter approach. Experimental data previously acquired have been used to validate the models and to replicate real working conditions of the machine in the simulation environment. A typical on-field manoeuvre has been used as duty cycle, to perform an effective energetic analysis. The standard hydraulic circuit is a multi-users load sensing system that uses a single variable displacement pump to feed steering, trailer brake and auxiliary utilities in that order. The key idea of the proposed solutions is the separation of steering from the other implements, to optimize the entire energy management. In particular, the paper investigates new and flexible solutions for the auxiliary utilities, including an electro-hydraulic load sensing architecture with variable pump margin, an electronic flow matching and flow sharing architecture, and an electronic strategy for automatic pressure compensation. The simulation results show that good energy saving can be achieved with the alternative architectures, so that physical prototyping of the most promising solutions will be realized as next step of the project

TEMPO-oxidized cellulose nanofibril/polyvalent cations hydrogels: a multifaceted view of network interactions and inner structure

In the last years, hydrogels from renewable biopolymers and low-cost row materials are a hot topic for biomedical applications. In this context, cellulose nanofibrils are considered suitable building blocks for the synthesis of many biocompatible products, with a variety of chemical-physical properties. Herein we report a multi-technique and multi-scale study, from the molecular to the nanometric length scale, of the sol-gel transition observed in aqueous solutions of TEMPO-oxidized nano-sized cellulose fibrils (TOCNFs), when in the presence of polyvalent cations (Mg2+ and Ca2+). We combine the data from Small Angle Neutron Scattering (SANS), which provide information about the inner structure of the nanofibril, with those from UV Resonant Raman (UVRR) spectroscopy, which is a sensitive probe of the intra- and inter-molecular interactions in the gel and the liquid state. The transition between the gel and the liquid phases is investigated as a function of the concentration of both TOCNFs and cations, the nature of the latter, and the pH at which the phenomenon is observed. SANS analysis reveals that ion concentration induces an anisotropic swelling in the nanofibrils which, at the same time, become more and more flexible. The nanofibrils flexibility is also dependent on TOCNF concentration and pH value. UVRR allows us to elucidate the structural organization and hydrogen-bonding properties of water in aqueous TOCNF dispersions and gels, showing how water molecules partially lose their typical bulk-like tetrahedral organization when ions are added, and the gel phase is formed

Effects of the equilibrium atmosphere on Taleggio cheese storage in micro perforated packaging

Taleggio is an Italian smear-ripened cheese, whose complex microbiota demands the optimisation of the packaging system to avoid excessive changes during storage. Metabolic processes of the cheese rind microbiota can be usefully exploited in equilibrium modified atmosphere packaging (EMAP) by balancing microbiota respiration and film permeation. Here, we present the application of three different micro perforated EMAPs as models for smear-ripened cheese compared to two control packaging configurations. Analyses of the main microbial groups, headspace gas, textural profile, and sensory properties were performed to find the best packaging for storage. Results showed that two of the alternative micro perforated packaging systems were able to control the excessive changes during storage, thus limiting fungal overgrowth and allowing the typical development of smear microbiota with minor changes to hardness and cohesiveness. Finally, the sensory evaluation positively favoured one of the alternatively packed cheeses based on its compactness, typical dairy traits, and minor off-flavours. These findings showed that EMAP can be a valid alternative solution to control the storage of Taleggio cheese. Further studies could be conducted to evaluate this system on other smear cheeses

Bioactive hydrogels: Design and characterization of cellulose-derived injectable composites

Cellulose represents a low cost, abundant, and renewable polysaccharide with great versatility; it has a hierarchical structure composed of nanofibers with high aspect ratio (3–4 nm wide, hundreds of µm long). TEMPO-mediated oxidation represents one of the most diffused methods to obtain cellulose nanofibers (CNFs): It is possible to obtain physically crosslinked hydrogels by means of divalent cation addition. The presence of inorganic components, such as calcium phosphates (CaP), can improve not only their mechanical properties but also the bioactivity of the gels. The aim of this work is to design and characterize a TEMPO-oxidized cellulose nanofibers (TOCNFs) injectable hydrogel embedded with inorganic particles, CaP and CaP-GO, for bone tissue regeneration. Inorganic particles act as physical crosslinkers, as proven by rheological characterization, which reported an increase in mechanical properties. The average load value registered in injection tests was in the range of 1.5–4.4 N, far below 30 N, considered a reasonable injection force upper limit. Samples were stable for up to 28 days and both CaP and CaP-GO accelerate mineralization as suggested by SEM and XRD analysis. No cytotoxic effects were shown on SAOS-2 cells cultured with eluates. This work demonstrated that the physicochemical properties of TOCNFs-based dispersions could be enhanced and modulated through the addition of the inorganic phases, maintaining the injectability and bioactivity of the hydrogels

3D Bioprinting of Pectin-Cellulose Nanofibers Multicomponent Bioinks

Pectin has found extensive interest in biomedical applications, including wound dressing, drug delivery, and cancer targeting. However, the low viscosity of pectin solutions hinders their applications in 3D bioprinting. Here, we developed multicomponent bioinks prepared by combining pectin with TEMPO-oxidized cellulose nanofibers (TOCNFs) to optimize the inks’ printability while ensuring stability of the printed hydrogels and simultaneously print viable cell-laden inks. First, we screened several combinations of pectin (1%, 1.5%, 2%, and 2.5% w/v) and TOCNFs (0%, 0.5%, 1%, and 1.5% w/v) by testing their rheological properties and printability. Addition of TOCNFs allowed increasing the inks’ viscosity while maintaining shear thinning rheological response, and it allowed us to identify the optimal pectin concentration (2.5% w/v). We then selected the optimal TOCNFs concentration (1% w/v) by evaluating the viability of cells embedded in the ink and eventually optimized the writing speed to be used to print accurate 3D grid structures. Bioinks were prepared by embedding L929 fibroblast cells in the ink printed by optimized printing parameters. The printed scaffolds were stable in a physiological-like environment and characterized by an elastic modulus of E = 1.8 ± 0.2 kPa. Cells loaded in the ink and printed were viable (cell viability >80%) and their metabolic activity increased in time during the in vitro culture, showing the potential use of the developed bioinks for biofabrication and tissue engineering applications