Carbon Nanostructures for Actuators: An Overview of Recent Developments

In recent decades, micro and nanoscale technologies have become cutting-edge frontiers in material science and device developments. This worldwide trend has induced further improvements in actuator production with enhanced performance. A main role has been played by nanostructured carbon-based materials, i.e., carbon nanotubes and graphene, due to their intrinsic properties and easy functionalization. Moreover, the nanoscale decoration of these materials has led to the design of doped and decorated carbon-based devices effectively used as actuators incorporating metals and metal-based structures. This review provides an overview and discussion of the overall process for producing AC actuators using nanostructured, doped, and decorated carbon materials. It highlights the differences and common aspects that make carbon materials one of the most promising resources in the field of actuators

Development of Coffee Biochar Filler for the Production of Electrical Conductive Reinforced Plastic

In this work we focused our attention on an innovative use of food residual biomasses. In particular, we produced biochar from coffee waste and used it as filler in epoxy resin composites with the aim to increase their electrical properties. Electrical conductivity was studied for the biochar and biochar-based composite in function of pressure applied. The results obtained were compared with carbon black and carbon black composites. We demonstrated that, even if the coffee biochar had less conductivity compared with carbon black in powder form, it created composites with better conductivity in comparison with carbon black composites. In addition, composite mechanical properties were tested and they generally improved with respect to neat epoxy resin

Analisi e miglioramento di un sistema radio Tetra in uso presso un'azienda di trasporto pubblico locale

Analisi del sistema radio in tecnologia Tetra in uso presso la rete di trasporti pubblici della città di Bologna gestita da Tper spa, individuazione delle criticità e proposte per possibili miglioramenti ed aggiornamenti

A Short Review on Nanostructured Carbon Containing Biopolymer Derived Composites for Tissue Engineering Applications

The development of new scaffolds and materials for tissue engineering is a wide and open realm of material science. Among solutions, the use of biopolymers represents a particularly interesting area of study due to their great chemical complexity that enables creation of specific molecular architectures. However, biopolymers do not exhibit the properties required for direct application in tissue repair—such as mechanical and electrical properties—but they do show very attractive chemical functionalities which are difficult to produce through in vitro synthesis. The combination of biopolymers with nanostructured carbon fillers could represent a robust solution to enhance composite properties, producing composites with new and unique features, particularly relating to electronic conduction. In this paper, we provide a review of the field of carbonaceous nanostructure-containing biopolymer composites, limiting our investigation to tissue-engineering applications, and providing a complete overview of the recent and most outstanding achievements

A Short Review on Biomedical Applications of Nanostructured Bismuth Oxide and Related Nanomaterials

In this review, we reported the main achievements reached by using bismuth oxides and related materials for biological applications. We overviewed the complex chemical behavior of bismuth during the transformation of its compounds to oxide and bismuth oxide phase transitions. Afterward, we summarized the more relevant studies regrouped into three categories based on the use of bismuth species: (i) active drugs, (ii) diagnostic and (iii) theragnostic. We hope to provide a complete overview of the great potential of bismuth oxides in biological environments

Bio-oils from microwave assisted pyrolysis of cellulose using a multi mode batch reactor

The end of fossil fuels era is becoming day by day [1] however the request of raw materials and fuels from industry is growing every year [2]. As a consequence research for renewable resource to supply oil is became very attractive [3]. Biomasses are very promising sources to satisfy the growing request of energy and raw materials [4-6] and in the same time to reduce the environmental impact due to their production [7]. Cellulose is particular interesting among different available biomasses because it is not interfere with the availability of resource for alimentation [8]. It is the main component of woody biomasses (until 50%) [9], and it is the most abundant polysaccharide and it may be the source of chemicals through a pyrolysis process [10]. Pyrolysis of cellulose through a classic heating was reported in several papers [11, 12] together with kinetic of the process and the main decomposition mechanism [13, 14] where a high formation of levoglucosan is proposed [15]. Levoglucosan is an anhydrosugar employed for the production of unhydrolysable glucose polymers [16] or in the production of bioethanol [17]. Furthermore through pyrolysis of cellulose a great variety of very attractive furanosidic compounds like furfural and hydroxyfurfural [18] may be obtained. In recent year the classical thermal heating is flanked with a new systems based on the use of microwave (MW) heating [19] because microwave assisted pyrolysis (MAP) is an interesting way to perform pyrolysis in a very short time and with the possibility of an easy control of the energy employed in the process [20, 21]. MAP was used to process different waste polymeric materials [22-25] in different conditions [26] to produce chemicals and fuels. Microwave are not absorbed and converted into heat by every materials, so MAP was frequently performed in the presence of a MW absorber. MAP of biomass has proven to be a reliable tool to employ waste biomass as the raw material for the process [27, 28] in the presence or the absence of a MW absorber and its conversion into chemicals [29] with good yields of bio-oils was reported. However the use of a MW absorber affects the quality and quantity of bio-oils as reported by Undri et al. [30]. Please click Additional Files below to see the full abstract

Microwave assisted pyrolysis of waste from short rotation coppice of poplar

Poplar short rotation coppice (SRC) plays an important role in biomass production because they are largely employed both in industry or used as solid fuel [1]. Recently there is a great interest in the below-ground biomass recovery (stump-root system) of poplar SRC because: a) it accounts for about 20% of the total plant dry weight [2] and the average poplar chips can yield 18 ton/ha of root biomass; b) it is easily accessible and harvested (sand-loamy soils); c) the root wood often has higher heating values than tops and branches, and may prove to be a better fuel [3]. Furthermore, the removal of the stump-roots systems does not require the payment of a concession, and using efficient recovery systems, the delivered cost might range from 28 to 66 €/ton[4]. The most common method to dispose waste from forestry biomass is combustion, which is an environmentally unfriendly process. Recently a remarkable interest has been focused on microwave assisted pyrolysis (MAP) of biomass due to the fast and efficient heating and the appealing characteristics of the products obtained [5]. Biomass are able to absorb microwave (MW) and even if a MW absorber is not strictly necessary, it may have some positive effects on the quality of products and pyrolysis time [6]. In this work MAP of residues from SRC of different poplar clones have been studied in a multimode batch oven.. MAP of stump-roots and leaves residues from different poplar clones were thoroughly investigated to produce high quantity and quality of bio-oils. They were obtained with high yield (up to 32.0%) and small water percentage (up to 17.5 %)and showed low density and viscosity and they were fluid at room temperature. Among bio-oils a sample with high acetic acid concentration (543.3 mg/mL) was obtained. Bio-oils were characterized with several analytical techniques: 1H-NMR, IR-ATR, density and viscosity measurements, and an original and innovative quatitative GC-MS method[7, 8]. These techniques let to make possible a detailed study on the bio-oils to define a correlation between their chemical and rheological properties with the parameters of the process. Please click Additional Files below to see the full abstract

Investigation of different types of biochar on the thermal stability and fire retardance of ethylene-vinyl acetate copolymers

In this work, three biochars, deriving from soft wood, oil seed rape, and rice husk and differing as far as the ash content is considered (2.3, 23.4, and 47.8 wt.%, respectively), were compounded in an ethylene vinyl acetate copolymer (vinyl acetate content: 19 wt.%), using a co-rotating twin-screw extruder; three loadings for each biochar were selected, namely 15, 20, and 40 wt.%. The thermal and mechanical properties were thoroughly investigated, as well as the flame retardance of the resulting compounds. In particular, biochar, irrespective of the type, slowed down the crystallization of the copolymer: this effect increased with increasing the filler loading. Besides, despite a very limited effect in flammability tests, the incorporation of biochar at increasing loadings turned out to enhance the forced-combustion behavior of the compounds, as revealed by the remarkable decrease of peak of heat release rate and of total heat release, notwithstanding a significant increase of the residues at the end of the tests. Finally, increasing the biochar loadings promoted an increase of the stiffness of the resulting compounds, as well as a decrease of their ductility with respect to unfilled ethylene vinyl acetate (EVA), without impacting too much on the overall mechanical behavior of the copolymer. The obtained results seem to indicate that biochar may represent a possible low environmental impact alternative to the already used flame retardants for EVA, providing a good compromise between enhanced fire resistance and acceptable mechanical properties