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The Interstage 2/3 is the structure that interfaces the Z40 second stage with the Z9 third stage on the VEGA-C launch vehicle. The primary structure is a regular and rather dense network of interlaced hoop and helical unidirectional ribs obtained using a continuous deposition process of carbon fibres followed by epoxy resin infusion. This grid structure is completed with a thin outer carbon skin which has a secondary structural role. The current work presents the production and mechanical testing of the scale one demonstration model. It demonstrates the suitability of the composite grid technology for carrying launcher structures applications.

The substitution of the fossil-derived polymers with materials from renewable resources is a great challenge, and many efforts are carried out to improve their technical performances, usually quite poor respect to the petro-based polymers. Among biopolyesters, poly(butylene succinate) (PBS) is interesting because it shows balanced performances in terms of thermal and mechanical properties as well as good processability and biodegradability. However, insufficient stiffness, low melt strength and viscosity, as well as low gas barrier properties are some of the lacks of PBS. The nanocomposite technology allows overcoming such deficiencies and represents an opportunity to obtain high-performing materials. For this purpose, bionanocomposites based on PBS and a novel organo-modified layered double hydroxide (LDH) have been prepared by in situ polymerization (Figure 1). In order to enhance the compatibilization of the inorganic filler with the polymer matrix, an oligomer of PBS was intercalated between the layers of the clay. Composites with different percentages of filler (1, 3, 5, 10 wt%) and two different divalent cations (Zn or Mg) were prepared. The thermal, rheological and mechanical properties of the samples were investigated. The results showed that the materials feature a high thermal stability, in particular those containing Zn2+ cations. Rheological investigations highlighted a significant chain extender effect of the filler toward the matrix, thus revealing a huge reinforcing effect imparted by the clays, especially for composites with Mg2+ cations. Such findings were also supported by an increase up to 30% of the tensile and flexural strength for a PBS composite loaded with 3 wt% of Mg/Al-LDH, thus suggesting a uniform level of dispersion and a pronounced interfacial interaction between the filler and polymer [1-3]. The setting up of these biocomposites allows widening the field of application of PBS to sectors requiring better performances as well as barrier effect and opens such new strategy to other biopolymers.

Various electrocardiographic and vectorcardiographic (ECG-VCG) patterns of ventricular conduction disturbances are inducible by premature right atrial stimulation (PRAS). These patterns are a consequence of different degrees of refractoriness in the specialized ventricular conduction system. We observed that the intermediate phase of left bundle branch block (LBBB) induced by PRAS in 20 subjects with normal basal QRS (complexes) were similar to those of left ventricular hypertrophy (LVH). In 18 patients with basal ECG-VCG signs of LVH, right bundle branch block (RBBB) induced by PRAS produced a progressive disappearance of these signs and the "normalization" of the tracings. The initial maximum QRS vector decreased, disappeared or remained absent in the patients with LBBB induced by PRAS, and appeared (when absent in the basal VCG) and remained unchanged (when present) in patients with RBBB induced by PRAS. In this paper we discuss the electrogenetic implications of these data. The ECG-VCG sings of LVH are probably dependent on a slowed conduction in the left bundle branch system, while anatomical hypertrophy per se probably plays a less important role.

To assess the incidence of coronary artery disease in patients with valvular aortic stenosis and its implication on peak systolic valvular gradient, 31 consecutive patients who underwent cardiac catheterization were examined. Associated significant coronary artery disease (50% reduction in luminal diameter evaluated in proximal segments and right dominant circulation) was present in 54.8% of patients. There was no difference in the distribution of risk factors among patients with and without significant luminal narrowings. The prevalence of coronary artery disease was found not to be significantly correlated with age (p = 0.276). There was no relationship between typical angina pectoris and the presence of coronary artery disease (p = 0.063). Fourty-seven percent of cases resulted free of chest pain. Ejection fraction was found to be significantly lower in patients with coronary artery disease (45 +/- 14.2%) than in patients without coronary artery disease (65.1 +/- 3.9%; p = 0.03) and a reverse relationship was observed between the presence of coronary artery disease and peak systolic valvular gradient (p = 0.006) which, in turn, correlated significantly with ejection fraction (r = 0.68; p = 0.023). These data demonstrate that the value of peak systolic valvular gradient, as the only index for the evaluation of the severity of aortic stenosis, is greatly limited in patients with associated coronary artery disease. Moreover, confirming the guidelines of the American College of Cardiology and of the American Heart Association task force, these data also stress the necessity of performing coronary angiography regardless angina pectoris is present or not.

The use of degrading enzymes in polymer formulation is a very attractive strategy to manage the end-of-life of plastics. However, high temperatures cause the denaturation of enzymes and the loss of their catalytic activity; therefore, protection strategies are necessary. Once protected, the enzyme needs to be released in appropriate media to exert its catalytic activity. A successful protection strategy involves the use of layered double hydroxides: cutinase, selected as a highly degrading polyester hydrolytic enzyme, is thermally protected by immobilization in Mg/Al layered double hydroxide structures. Different triggering media are here evaluated in order to find the best releasing conditions of cutinase from LDH. In detail, phosphate and citrate–phosphate buffers, potassium carbonate, sodium chloride, and sodium sulfate solutions are studied. After the comparison of all media in terms of protein release and activity retained, phosphate buffer is selected as the best candidate for the release of cutinase from LDH, and the effect of pH and concentration is also evaluated. The amount of the enzyme released is determined with the Lowry method. Activity tests are performed via spectrophotometry.

Particulate composites based on poly(lactic acid) (PLA) and poly(butylene succinate) (PBS) biopolymers have been formulated. Silver skin (SSK), the by-product derived from the roasting of coffee beans, has been milled to micrometric size and added up to a 30 wt% of loading, without any previous treatment. The dynamic mechanical properties of the composites have been investigated, as well as the stability toward UV and IR radiation. The filler improves some mechanical properties such as the elastic modulus (E′) mostly in PBS. Photoaging experiments demonstrate that SSK, due to its polyphenols content and antioxidant activity, is able to protect both PLA and PBS from UV degradation, highlighting an added value of SSK waste-based composites.

In situ intercalative polymerization has been investigated as a strategic way to obtain poly(propylene 2,5-furandicarboxylate) (PPF) and poly(hexamethylene 2,5-furandicarboxylate) (PHF) nanocomposites with different graphene types and amounts. Graphene (G) has been dispersed in surfactant stabilized water suspensions. The loading range in composites was 0.25–0.75 wt %. For the highest composition, a different type of graphene (XT500) dispersed in 1,3 propanediol, containing a 6% of oxidized graphene and without surfactant has been also tested. The results showed that the amorphous PPF is able to crystallize during heating scan in DSC and graphene seems to affect such capability: G hinders the polymer chains in reaching an ordered state, showing even more depressed cold crystallization and melting. On the contrary, such hindering effect is absent with XT500, which rather induces the opposite. Concerning the thermal stability, no improvement has been induced by graphene, even if the onset degradation temperatures remain high for all the materials. A moderate enhancement in mechanical properties is observed in PPF composite with XT500, and especially in PHF composite, where a significative increase of 10–20% in storage modulus E’ is maintained in almost all the temperature range. Such an increase is also reflected in a slightly higher heat distortion temperature. These preliminary results can be useful in order to further address the field of application of furan-based polyesters, in particular, they could be promising as packaging materials.

Short chopped fibers coated by epoxy resin of different length (5 to 10 mm length) were added at low volume content (about 4.6% on the composite) to alkali-activated fly ash or metakaolin mortars. These uncured scraps derive from the production of carbon fiber-reinforced polymer composites and they are not presently recycled, despite their outstanding mechanical properties. The workability, microstructure, porosity, and physical and mechanical properties (mainly flexural strength) of the derived materials were investigated. Superior flexural strength and increased toughness were obtained. An acid treatment of the scraps further improved the mechanical properties of the mortars by changing the chemical structure of the surface, thus increasing the interaction with the inorganic phase. These results foster the use of these wastes to improve the performance of low carbon footprint building materials such as alkali-activated composites in the building industry.

When considered by a biorefinery approach, an agroindustrial byproduct such as wheat bran can find a new standing in the field of fabrication of mycelium-based materials. The present work reports on a systematic study on the effect of wheat bran as an upgrading feedstock for the growth and development of fully biobased and biodegradable composites. Two families of materials based on bran/cotton and bran/hemp mixtures were fabricated on an industrial scale. The natural materials thus obtained were fully characterized and their end-life was assessed in composting conditions. The research focusses on two main aspects: the nutritional contribution of bran for the fungal growth and its effect on the mechanical properties as a filler in the final composites. It must be noted that the valorization and exploitation of a byproduct such as bran can have a considerable impact on the industrial production of mycelium-based composite materials, by reducing the time of production while increasing their mechanical performances.