Optimum Mechanical Design of Binary Actuators Based on Shape Memory Alloys

This chapter describes the optimum mechanical design of shape memory based actuators. The authors show how to exploit the Shape Memory Alloy (SMA) to design silent, compact and light binary actuators. Two simple mechanical models are considered to describe the SMA behaviour and design equations are provided for two classes of actuators. First SMA actuators are analyzed and designed on the basis of the backup element needed to recover the stroke. Second SMA actuators are improved by adding a compensator system to enhance the output mechanical response, especially in terms of available stroke. Useful design procedures are provided to help the engineer in the synthesis of SMA actuators. Starting from the design specifications, a step by step procedure is built to define the mechanical dimension of the SMA active elements, of the backup system and of the compensator

In vivo genetic manipulation of inner ear connexin expression by bovine adeno-Associated viral vectors

We have previously shown that in vitro transduction with bovine adeno-associated viral (BAAV) vectors restores connexin expression and rescues gap junction coupling in cochlear organotypic cultures from connexin-deficient mice that are models DFNB1 nonsyndromic hearing loss and deafness. The aims of this study were to manipulate inner ear connexin expression in vivo using BAAV vectors, and to identify the optimal route of vector delivery. Injection of a BAAV vector encoding a bacterial Cre recombinase via canalostomy in adult mice with floxed connexin 26 (Cx26) alleles promoted Cre/LoxP recombination, resulting in decreased Cx26 expression, decreased endocochlear potential, increased hearing thresholds, and extensive loss of outer hair cells. Injection of a BAAV vector encoding GFP-tagged Cx30 via canalostomy in P4 mice lacking connexin 30 (Cx30) promoted formation of Cx30 gap junctions at points of contacts between adjacent non-sensory cells of the cochlear sensory epithelium. Levels of exogenous Cx30 decayed over time, but were still detectable four weeks after canalostomy. Our results suggest that persistence of BAAV-mediated gene replacement in the cochlea is limited by the extensive remodeling of the organ of Corti throughout postnatal development and associated loss of non-sensory cells

Potential production of biogas from prinkly pear (opuntia ficus-indica L.) in sicilian uncultivated areas

The aim of this work is to evaluate the potential production of biogas and, indirectly, biomethane or electric and thermal energy, from prinkly pear (Opuntia ficus-indica L.), to be grown in a part of Sicilian uncultivated areas and co-digested together with the available livestock manure and slurry. In order to increase the Renewable Energy Sources (RES) and reduce the dependency from fossil ones, the conversion of biomass into biogas through Anaerobic Digestion (AD) process is paramount for producing biomethane, to be used as fuel for means of transport and agricultural machines or heating, or electric and thermal energy through Combined Heat and Power (CHP) plants. Moreover, the digestate produced through AD process can be applied to soils as organic fertiliser in the place of chemical ones. Prinkly pear was supposed to be grown, by mechanising the harvest of cladods (modified stems), in a part of the Sicilian Used Agricultural Area that is currently uncultivated (totally 600, 000 ha ca.), identified by means of a GIS software. Thus it was possible to compute the potential production of biogas and, indirectly, biomethane or electric and thermal energy. The results show that the Sicilian potential production of biogas is 612, 115 103m3, from which 342, 784 103m3of biomethane could be extracted or 67, 038 MWh of electric energy and 70, 390 MWh MWh of thermal energy could be generated. Moreover the obtained digestate would be used as biofertiliser, within both conventional and organic farming. This work demonstrates that the production of RES, such as biogas from prinkly pear, represents a very profitable way of using the uncultivated areas: the income of the farmer would include not only that deriving from the sale of biomethane or electric and thermal energy but also the saving for replacing chemical fertilisers with digestate and the subsidy for producing biomethane as fuel for means of transport or electric and thermal energy from biogas

Sicilian potential biogas production from Citrus industry by-product

In Europe, Italy is the second nation after Spain in Citrus production and 49% ca. of national fruit production is located in Sicily. The by-product obtained from the industrial processing of Citrus fruits into juice and essential oils is called \u201cpastazzo\u201d or Citrus Waste (CW). This study is aimed at evaluating the Sicilian potential biogas and energy production from the above \u201cpastazzo\u201d and verifying the possibility of using this by-product for Anaerobic Digestion (AD) process within 30 km from processing plants. The areas cultivated with Citrus species in Sicily and their distribution in the various municipal districts were mapped and analysed by means of QGIS software, together with the main Citrus processing plants and the three existing AD plants. The statistical data about the amounts of the by-product of Citrus processing industry were evaluated, in order to compute the Sicilian potential biogas and energy production. In Sicily it is possible to obtain, through the use of \u201cpastazzo\u201d, a yearly production of 12,916,800 m3 ca. of biogas, equal to 24,250,930 kWh of electric energy and 25,463,477 kWh of thermal energy or 6,200,064 m3 of biomethane. This high potential biogas and energy production is not be currently used in a sustainable way from the energetic and economic points of view, because the existing AD plants are farer than 30 km from Citrus processing plants. The CW produced in Sicily could be used inside a bio-reactor, together with other raw materials (e.g. pomace and wastewater from olive oil mills, cereal straw, poultry manure and Italian sainfoin or Hedysarum coronarium), for AD process

Comparison of Mechanical, Assisted and Manual Harvest of Origanum vulgare L.

In Italy, the production of Origanum vulgare L. is lower than the national market demand, so there is an increasing interest in this crop, even if the manual harvest and bunch binding represent ca. 60% of the production cost. The aim of this work is to evaluate the harvest efficiency, as well as the working capacity, productivity and quality of mechanical harvesting by means of a reaper-binder designed for cereal and forage crops and assisted harvesting by means of a long-reach edge trimmer. In fact, the final aim is to suggest a machine and a method for oregano harvesting that could significantly reduce the time and, therefore, the cost of this crop operation, while achieving a product quality similar to that obtained by manual harvesting. Tests of mechanical and assisted harvesting were carried out using a reaper-binder after modifying it (i.e., reducing its forward speed, cutting height and bunch size to improve its working capacity, productivity and quality) and an edge trimmer, respectively. The tests of mechanical and assisted harvesting were compared with manual harvesting. In the testing field, with an irregular shape and an area of one hectare, nine rows were selected and divided into three replications, each comprising three tests, i.e., mechanical, assisted and manual harvesting. The modified reaper-binder allowed us to achieve working capacity and productivity rates much higher than those obtained with manual harvesting. Moreover, its harvest quality, in terms of bunch weight and binding height, favourably compares with that manually obtained. Furthermore, the edge trimmer allowed us to achieve working capacity and productivity rates lower than those obtained by means of the reaper-binder but much higher than in manual harvesting. Thus, the reaper-binder can minimise the harvest time and, therefore, cost while harvesting bunches slightly bigger than those manually harvested, even if it requires a high initial investment cost. Instead, the edge trimmer can be a cheap solution for reducing the harvest time and cost. Therefore, mechanical and assisted harvesting could spread oregano production in areas of inland Sicily and other Mediterranean regions that are often cultivated with low-profit herbaceous plant species or lie fallow. Thus, it would be possible to increase farmers’ incomes and job opportunities, as well as preventing or minimising the hydrogeological instability in these areas

Coarse Grained Density Functional Theories for Metallic Alloys: Generalized Coherent Potential Approximations and Charge Excess Functional Theory

The class of the Generalized Coherent Potential Approximations (GCPA) to the Density Functional Theory (DFT) is introduced within the Multiple Scattering Theory formalism for dealing with, ordered or disordered, metallic alloys. All GCPA theories are based on a common ansatz for the kinetic part of the Hohenberg-Kohn functional and each theory of the class is specified by an external model concerning the potential reconstruction. The GCPA density functional consists of marginally coupled local contributions, does not depend on the details of the charge density and can be exactly rewritten as a function of the appropriate charge multipole moments associated with each lattice site. A general procedure based on the integration of the 'qV' laws is described that allows for the explicit construction the same function. The coarse grained nature of the GCPA density functional implies great computational advantages and is connected with the O(N) scalability of GCPA algorithms. Moreover, it is shown that a convenient truncated series expansion of the GCPA functional leads to the Charge Excess Functional (CEF) theory [E. Bruno, L. Zingales and Y. Wang, Phys. Rev. Lett. {\bf 91}, 166401 (2003)] which here is offered in a generalized version that includes multipolar interactions. CEF and the GCPA numerical results are compared with status of art LAPW full-potential density functional calculations for 62, bcc- and fcc-based, ordered CuZn alloys, in all the range of concentrations. These extensive tests show that the discrepancies between GCPA and CEF are always within the numerical accuracy of the calculations, both for the site charges and the total energies. Furthermore, GCPA and CEF very carefully reproduce the LAPW site charges and the total energy trends.Comment: 19 pages, 11 figure

A Human-Derived Monoclonal Antibody Targeting Extracellular Connexin Domain Selectively Modulates Hemichannel Function

Connexin hemichannels, which are plasma membrane hexameric channels (connexons) composed of connexin protein protomers, have been implicated in a host of physiological processes and pathological conditions. A number of single point pathological mutations impart a "leaky" character to the affected hemichannels, i.e., make them more active or hyperactive, suggesting that normal physiological condition could be recovered using selective hemichannel inhibitors. Recently, a human-derived monoclonal antibody named abEC1.1 has been shown to inhibit both wild type and hyperactive hemichannels composed of human (h) connexin 26 (hCx26) subunits. The aims of this work were (1) to characterize further the ability of abEC1.1 to selectively modulate connexin hemichannel function and (2) to assess its in vitro stability in view of future translational applications. In silico analysis of abEC1.1 interaction with the hCx26 hemichannel identified critically important extracellular domain amino acids that are conserved in connexin 30 (hCx30) and connexin 32 (hCx32). Patch clamp experiments performed in HeLa DH cells confirmed the inhibition efficiency of abEC1.1 was comparable for hCx26, hCx30 and hCx32 hemichannels. Of note, even a single amino acid difference in the putative binding region reduced drastically the inhibitory effects of the antibody on all the other tested hemichannels, namely hCx30.2/31.3, hCx30.3, hCx31, hCx31.1, hCx37, hCx43 and hCx45. Plasma membrane channels composed of pannexin 1 were not affected by abEC1.1. Finally, size exclusion chromatography assays showed the antibody does not aggregate appreciably in vitro. Altogether, these results indicate abEC1.1 is a promising tool for further translational studies

A ratchet mechanism for amplification in low-frequency mammalian hearing

The sensitivity and frequency selectivity of hearing result from tuned amplification by an active process in the mechanoreceptive hair cells. In most vertebrates the active process stems from the active motility of hair bundles. The mammalian cochlea exhibits an additional form of mechanical activity termed electromotility: its outer hair cells (OHCs) change length upon electrical stimulation. The relative contributions of these two mechanisms to the active process in the mammalian inner ear is the subject of intense current debate. Here we show that active hair-bundle motility and electromotility can together implement an efficient mechanism for amplification that functions like a ratchet: sound-evoked forces acting on the basilar membrane are transmitted to the hair bundles whereas electromotility decouples active hair-bundle forces from the basilar membrane. This unidirectional coupling can extend the hearing range well below the resonant frequency of the basilar membrane. It thereby provides a concept for low-frequency hearing that accounts for a variety of unexplained experimental observations from the cochlear apex, including the shape and phase behavior of apical tuning curves, their lack of significant nonlinearities, and the shape changes of threshold tuning curves of auditory nerve fibers along the cochlea. The ratchet mechanism constitutes a general design principle for implementing mechanical amplification in engineering applications.Comment: 6 pages, 4 figures, plus Supplementary Information. Animation available on the PNAS website (http://dx.doi.org/10.1073/pnas.0914345107)

Images of an equatorial outflow in SS433

We have imaged the X-ray binary SS433 with unprecedented Fourier-plane coverage at 6cm using simultaneously the VLBA, MERLIN, and the VLA, and also at 20cm with the VLBA. At both wavelengths we have securely detected smooth, low-surface brightness emission having the appearance of a `ruff' or collar attached perpendicularly to the well-studied knotty jets in this system, extending over at least a few hundred AU. We interpret this smooth emission as a wind-like outflow from the binary, and discuss its implications for the present evolutionary stage of this system.Comment: Accepted by ApJ Letter