SMA applications in an innovative multishot deployment mechanism

An innovative Deployment and Retraction hinge Mechanism (DARM) in the frame of a technological program is examined. The mechanism includes two restraint/release devices, which enable it to be stable in its stowed or deployed position while sustaining all associated loads, and to carry its payload by remote command. The main characteristics of the DARM are as follows: deployment and retraction movements are spring actuated; the available amount of functional sequences is almost unlimited; and no use of electrical motors is made. These features were accomplished by: the application of a special kinematic scheme to the mechanical connection between the spring motor and the swivel head arm; and the use of shape memory alloys (SMA) actuators for both release and spring recharge functions. DARM is thus a mechanism which can find many applications in the general space scenario of in-orbit maintenance and servicing. In such a frame, the DARM typical concept, which has a design close to very simple one-shot deployment mechanisms, has a good chance to replace existing analog machines. Potential items that could be moved by DARM are: booms for satellite instruments; antenna reflector tips; entire antenna reflectors; and solar panels

A Catalytic One-Pot Synthesis of Indolyl Cyclobutanones

A general strategy for the synthesis of indolyl cyclobutanones via a tandem Bronsted acid catalyzed 2-hydroxycyclobutanone activation-indole nucleophilic addition has been exploited. The procedure leads to a wide range of 2- and 3-functionalized indole derivatives in good to high yields with broad substrate scope

Design, synthesis and biological activity of selective hCAs inhibitors based on 2-(benzylsulfinyl)benzoic acid scaffold

A large library of derivatives based on the scaffold of 2-(benzylsulfinyl)benzoic acid were synthesised and tested as atypical inhibitors against four different isoforms of human carbonic anhydrase (hCA I, II, IX and XII, EC 4.2.1.1). The exploration of the chemical space around the main functional groups led to the discovery of selective hCA IX inhibitors in the micromolar/nanomolar range, thus establishing robust structure-activity relationships within this versatile scaffold. HPLC separation of some selected chiral compounds and biological evaluation of the corresponding enantiomers was performed along with molecular modelling studies on the most active derivatives

Fiber Bragg Gratings for Prognostics in Space Applications: A Thermo-Mechanical Characterization of Minimally Invasive Sensing Techniques

Upcoming space missions will be characterized by longer duration, higher level of autonomy of the spacecraft and more extensive human presence. These aspects require robust and reliable health monitoring strategies in order to extend the spacecraft operations, increase safety of manned missions and adaptively tailor extended mission profiles according to the actual system health condition. In this context, Prognostics and Health Management (PHM) provide useful tools to determine the system health, estimate its Remaining Useful Life (RUL) and adjust operations to avoid overstressing components. In order to gather the necessary information from the monitored system and estimate its actual health condition and RUL, a distributed network of sensors is needed, measuring heterogeneous quantities with high accuracy and high spatial resolution. Traditional technologies usually require invasive and heavy installations, and prevent fully leveraging the potentialities of PHM algorithms. In this work, we propose the use of optical sensors for strain, temperature and vibration monitoring; an experimental campaign has been carried out to validate this technology, and the results are compared with traditional sensing techniques

Study of Packaging and Installation of FBG Sensors for Monitoring of Aircraft Systems

Next generation aircraft systems will feature an ever increasing complexity. In this context, advanced health monitoring strategies will be required to ensure a high level of operations safety as well as a good reliability. Hence, Prognostics and Health Management (PHM) is emerging as an enabling discipline for future advanced aircraft design and operations, with a particular application to Flight Control System (FCS) monitoring. One of the most critical issues for real-time Fault Detection and Identification (FDI) of aircraft FCS is the availability of actuator load measurements. The aerodynamic load on flight control actuators has a significant influence on their dynamic response, and can easily hide the effect of incipient failure precursors. For this reason, real-time monitoring FDI algorithms relying on the comparison between the actual system response and that of a digital twin require either a measure or an estimation of aerodynamic loads. Usually, this quantity is not monitored by a dedicated sensor, since it is not required as a feedback signal by most control logics. A dedicated load sensor for PHM with traditional technologies is not easily feasible: for example, a load cell would be mechanically connected in series with the actuator, adding a potential single failure point and affecting the overall system safety; the use of strain gages on the structure is less accurate, and requires several sensors with individual wiring and complex signal conditioning circuitry. Optical strain sensors based on Fiber Bragg Gratings (FBG) allow indirect load measurement combined with real-time structural monitoring, combining an acceptable increase in complexity and costs with a high robustness. In this preliminary study, we installed an FBG monitoring system on a UAV to assess the feasibility of such technology. Measures of structure deflection were correlated to actuator position and IMU data, to estimate aerodynamic loads

Mealworm (Tenebrio molitor): Potential and challenges to promote circular economy

Over the last few years, the concept of Circular Economy (CE) has received a lot of atten-tion due to its potential contribution to the Sustainable Development Goals (SDGs), especially by reconciling economic growth with the protection of the environment through its grow-make-use-restore approach. The use of insects in circular production systems has been a good example of this concept as insects can transform a wide range of organic waste and by-products into nutritious feedstuffs, which then go back into the production cycle. This paper explores the potential of meal-worms (Tenebrio molitor) in circular production systems by reviewing their use and applicability in several industries such as pharmaceuticals, agriculture, food, etc. Despite the high versatility of this insect and its potential as a substitute source of nutrients and other valuable components, there are still many legislative and behavioural challenges that hinder its adoption and acceptance

As(III, V) Uptake from Nanostructured Iron Oxides and Oxyhydroxides: The Complex Interplay between Sorbent Surface Chemistry and Arsenic Equilibria

Iron oxides/oxyhydroxides, namely maghemite, iron oxide-silica composite, akaganeite, and ferrihydrite, are studied for AsV and AsIII removal from water in the pH range 2–8. All sorbents were characterized for their structural, morphological, textural, and surface charge properties. The same experimental conditions for the batch tests permitted a direct comparison among the sorbents, particularly between the oxyhydroxides, known to be among the most promising As-removers but hardly compared in the literature. The tests revealed akaganeite to perform better in the whole pH range for AsV (max 89 mg g−1 at pH0 3) but to be also efficient toward AsIII (max 91 mg g−1 at pH0 3– 8), for which the best sorbent was ferrihydrite (max 144 mg g−1 at pH0 8). Moreover, the study of the sorbents’ surface chemistry under contact with arsenic and arsenic-free solutions allowed the understanding of its role in the arsenic uptake through electrophoretic light scattering and pH measurements. Indeed, the sorbent’s ability to modify the starting pH was a crucial step in determining the removal of performances. The AsV initial concentration, contact time, ionic strength, and presence of competitors were also studied for akaganeite, the most promising remover, at pH0 3 and 8 to deepen the uptake mechanism

On the role of the nature and density of acid sites on mesostructured aluminosilicates dehydration catalysts for dimethyl ether production from CO2

In this work, we designed four different mesostructured acidic materials to be used as methanol dehydration catalysts for the one-pot CO2-to-DME process, in the form of physical mixtures with a Cu/ZnO/Al2O3-based commercial redox catalyst (CZA). The studied systems consist in a mesostructured gamma-Al2O3 and three mesostructured aluminosilicates (namely Al-MCM-41, Al-SBA-15, and Al-SBA-16) with the same Si/Al ratio (= 15) but significantly different textural properties. The main goal of this work is to understand how the textural features can influence the acidic properties (typology, amount, strength, surface density) and, consequently, how catalytic performances can be correlated with acidic features. On this note, we found that the systems presenting both Bronsted and Lewis sites (namely the three aluminosilicates) show much better catalytic performances than gamma-Al2O3, that only features Lewis sites, thus implying that Bronsted sites are more active towards methanol dehydration than Lewis sites. The three aluminosilicates, despite presenting comparable amounts of Bronsted sites, show significantly different performances in terms of selectivity to DME; particularly, Al-SBA-16, the system with the lowest surface area, proved to be the most efficient catalyst. This finding led us to infer that, besides Bronsted acidity, a high surface density of acid sites is a key factor to obtain a high dehydration activity; being methanol dehydration a bi-molecular reaction, the close proximity of two acid sites would indeed favor the kinetics of the process