Quartz Crystal Microbalances for Space: Design and Testing of a 3D Printed Quasi-Kinematic Support

Outgassing or thruster’s generated contaminants are critical for optical surfaces and optical payloads because scientific measurements and, in general, the performances can be degraded or jeopardized by uncontrolled contamination. This is a well-known issue in space technology that is demonstrated by the growing usage of quartz crystal microbalances as a solution for measuring material outgassing properties data and characterizing the on-orbit contamination environment. Operation in space requires compatibility with critical requirements, especially the mechanical and thermal environments to be faced throughout the mission. This work provides the design of a holding structure based on 3D printing technology conceived to meet the environmental characteristics of space application, and in particular, to face harsh mechanical and thermal environments. A kinematic mounting has been conceived to grant compatibility with a large temperature range, and it has been designed by finite element methods to overcome loading during the launch phases and cope with a temperature working range down to cryogenic temperatures. Qualification in such environments has been performed on a mockup by testing a prototype of the holding assembly between −110 °C and 110 °C and allowing verification of the mechanical resistance and stability of the electrical contacts for the embedded heater and sensor in that temperature range. Moreover, mechanical testing in a random environment characterized by an RMS acceleration level of 500 m/s2 and excitation frequency from 20 to 2000 Hz was successfully performed. The testing activity allowed for validation of the proposed design and opened the road to the possible implementation of the proposed design for future flight opportunities, also onboard micro or nanosatellites. Moreover, exploiting the manufacturing technology, the proposed design can implement an easy assembling and mounting of the holding system. At the same time, 3D printing provides a cost-effective solution even for small series production for ground applications, like monitoring the contaminants in thermo-vacuum chambers or clean rooms, or depositions chambers

Effects of Oscillation Amplitude Variations on QCM Response to Microspheres of Different Sizes

Suspended particulate matter (PMx) is one of the most important environmental pollutants. Miniaturized sensors capable of measuring and analyzing PMx are crucial in environmental research fields. The quartz crystal microbalance (QCM) is one of the most well-known sensors that could be used to monitor PMx. In general, in environmental pollution science, PMx is divided into two main categories correlated to particle diameter (e.g., PM < 2.5 µm and PM < 10 µm). QCM-based systems are capable of measuring this range of particles, but there is an important issue that limits the application. In fact, if particles with different diameters are collected on QCM electrodes, the response will be a result of the total mass of particles; there are no simple methods to discriminate the mass of the two categories without the use of a filter or manipulation during sampling. The QCM response depends on particle dimensions, fundamental resonant frequency, the amplitude of oscillation, and system dissipation properties. In this paper, we study the effects of oscillation amplitude variations and fundamental frequency (10, 5, and 2.5 MHz) values on the response, when particle matter with different sizes (2 µm and 10 µm) is deposited on the electrodes. The results showed that the 10 MHz QCM was not capable of detecting the 10 µm particles, and its response was not influenced by oscillation amplitude. On the other hand, the 2.5 MHz QCM detected the diameters of both particles, but only if a low amplitude value was used

Search for carbonaceous chondrites evidence on Vesta through the detection of carbonates

NASA’s Dawn mission was launched in September 2007 and orbited asteroids Vesta (2011 2012) and Ceres (2015–2018). Vesta shows surface dark units that have been suggested to be linked to exogenous materials and are therefore useful to understand the initial stages of the Solar System. This work takes advantage of the newly calibrated data of the VIR spectrometer, which are characterized by a better signal to noise (S/N) ratio, giving us the opportunity to search for spectral features that were never seen before due to noise. Considering that hydroxyl has been shown to be present in every dark unit on Vesta and also in carbonaceous chondrites, the goals of this work are the search for and characterization of carbonates that are present in carbonaceous chondrites, i.e., the supposed darkening agents of Vesta. The estimate of the abundances of carbonates is fundamental to identify which carbonaceous chondrite fell on Vesta; this can be crucial for the definition of an evolutionary history of Vesta and the Solar System. The study of a possible feature at 3.9 μm related to the presence of carbonates was analyzed and found to be noise-induced. Although spectral features related to carbonates were not observed, the 3.4 μm absorption band was analyzed anyway in order to fix an upper limit to the abundance of carbonates in carbonaceous chondrites on Vesta. This value is consistent with petrochemical analyses, i.e., no more than 0.2% of carbonates in carbonaceous chondrites

Detection of Crystalline and Fine-grained Calcic Plagioclases on Vesta

Accepted: 2019-06-2

Detection of Crystalline and Fine-grained Calcic Plagioclases on Vesta

Plagioclase feldspars are among the most prevalent minerals in the solar system, and are present in many chondritic and achondritic meteorite families. Nevertheless, spectral features of plagioclases have never been unambiguously and directly observed in remote observations of asteroids. We report here the detection of an absorption band at 12.2 μm on Vesta spectra provided by ground-based spectral observations at the Subaru Telescope. This signature represents the first direct evidence of a widespread presence of crystalline Ca-rich plagioclase on Vesta and reveals that its regolith is comminuted to a very fine grain size, smaller than a few tens of microns, indicating that the mechanical brecciation process has been very effective. The crystalline nature of plagioclase strongly suggests that impacts alone cannot be the sole mechanism for regolith formation on Vesta and a milder process, such as thermal fatigue, should be invoked as an important and concomitant process Thermal fatigue should be considered a very effective process in regolith production and rejuvenation not only for near-Earth asteroids but even for large asteroids located in the main belt

Condizionalità europea e identità costituzionali

La presente Sezione monografica trae origine dall’omonimo seminario organizzato presso l’Università degli Studi di Udine nel marzo 2023. Il tema della call for papers alla base del seminario – condizionalità europea e identità costituzionali – è stato scelto in quanto la condizionalità, o meglio le condizionalità, costituiscono meccanismi, di diversa matrice, sempre più presenti e pervasivi nel processo di integrazione europea, sia dal punto di vista quantitativo che da quello qualitativo. Essi agiscono sul versante orizzontale dei fini propri dell’Unione e dei rapporti tra i suoi organi, sul versante verticale dei rapporti tra Unione e Stati membri, sul versante esterno dei rapporti tra Unione e Stati candidati all’adesione, futuri candidati o Stati terzi. Gli strumenti di condizionalità rappresentano, così, uno stress test per alcuni dei tratti caratterizzanti dell’ordinamento sovranazionale, quali il limite delle competenze attribuite, il principio di parità tra Stati, la persistente oscillazione tra modello intergovernativo e modello comunitario, oggi unionale, fino a toccare, nelle più recenti evoluzioni, la stessa capacità prescrittiva dei valori di cui all’art. 2 TUE e la loro tenuta rispetto alle identità costituzionali degli Stati membri. Di qui la scelta di un tema che tocca il cuore dell’integrazione europea da molteplici sfaccettature. La Sezione si apre con un contributo di carattere generale su “L’utilizzo della condizionalità e la trasformazione dello spazio europeo” (A. Baraggia). I successivi contributi si possono raggruppare attorno a quattro nuclei tematici distinti che, tuttavia, si intersecano fra loro in maniera significativa. La condizionalità di bilancio connessa alla protezione dello Stato di diritto è analizzata da Adriano Dirri e Ylenia Guerra – che hanno scritto sulla controversa genesi e sulla «contestata applicazione» del Regolamento 2020/2092, evidenziando sia gli aspetti giuridici che le dinamiche politiche – e da Nicola Maffei, con un contributo che ne offre una lettura in chiave di evoluzione costituzionale dell’Unione, in correlazione con il piano Next Generation EU (NGEU). Il secondo nucleo di riflessione è costituito dalla condizionalità relativa all’utilizzo delle risorse finanziarie, in rapporto con la forma di governo nazionale: Federico Musso mette in luce la diversa incidenza dei vincoli sovranazionali di natura macroeconomica sulle decisioni finanziarie degli Stati membri, mentre Giulio Santini riprende l’elaborazione teorica sul concetto di indirizzo politico, proponendone l’utilizzo come chiave di lettura dell’efficacia dei meccanismi di condizionalità in ambito europeo. Ci si concentra poi su obiettivi settoriali di particolare rilevanza perseguiti dall’Unione con lo strumento della condizionalità. Paola Valerio descrive l’emergere del suo utilizzo per finalità di carattere ambientale, dalla politica di coesione alla politica agricola comune, sino al Dispositivo per la ripresa e la resilienza (cd. Recovery Fund). Roberto Vinceti, invece, approfondisce come il «formante negoziale» sotteso alla condizionalità possa spingere all’armonizzazione degli ordinamenti giudiziari nazionali, pur in assenza di competenze normative dell’Unione, facendo emergere un modello comune che i soli interventi della giurisprudenza sovranazionale non avrebbero potuto forgiare. L’ultima forma di condizionalità esaminata dai contributi della Sezione è quella insita nel procedimento di adesione ed è rivolta agli Stati candidati o potenziali candidati: Edin Skrebo analizza l’esperienza dei Balcani occidentali, e in particolare dei quattro Stati che erano parte della Repubblica Federale di Yugoslavia (Bosnia ed Erzegovina, Serbia, Montenegro e Macedonia del Nord), mentre Tatiana-Maria Cernicova-Dragomir parla dell’«associated trio» di Stati che, nel 2022, ha espresso la volontà di diventare parte dell’Unione: Ucraina, Moldavia e Georgia

Piezoelectric crystal microbalance measurements of enthalpy of sublimation of C₂–C₉ dicarboxylic acids

We present here a novel experimental set-up that is able to measure the enthalpy of sublimation of a given compound by means of piezoelectric crystal microbalances (PCMs). The PCM sensors have already been used for space measurements, such as for the detection of organic and non-organic volatile species and refractory materials in planetary environments. In Earth atmospherics applications, PCMs can be also used to obtain some physical–chemical processes concerning the volatile organic compounds (VOCs) present in atmospheric environments. The experimental set-up has been developed and tested on dicarboxylic acids. In this work, a temperature-controlled effusion cell was used to sublimate VOC, creating a molecular flux that was collimated onto a cold PCM. The VOC recondensed onto the PCM quartz crystal, allowing the determination of the deposition rate. From the measurements of deposition rates, it has been possible to infer the enthalpy of sublimation of adipic acid, i.e. Δ<i>H</i>_sub : 141.6 ± 0.8 kJ mol⁻¹, succinic acid, i.e. 113.3 ± 1.3 kJ mol⁻¹, oxalic acid, i.e. 62.5 ± 3.1 kJ mol⁻¹, and azelaic acid, i.e. 124.2 ± 1.2 kJ mol⁻¹. The results obtained show an accuracy of 1 % for succinic, adipic, and azelaic acid and within 5 % for oxalic acid and are in very good agreement with previous works (within 6 % for adipic, succinic, and oxalic acid and within 11 % or larger for azelaic acid)

Mapping olivine abundance on asteroid (25143) Itokawa from Hayabusa/NIRS data

Olivine is one of the main abundant mineral in the Solar System, and the determination of its abundance on a surface may give fundamental information about its evolution. The study of surface distribution of olivine on asteroid (25143) Itokawa through near-Infrared reflectance spectroscopy is a difficult goal because olivine and pyroxene bands centred at 1 μm and 2 μm are not entirely included in Hayabusa/NIRS’ spectral range. In this work, the retrieval of olivine abundance has been performed by applying two different methods: the first one uses some spectral indices to retrieve olivine abundance, whilst the second one consists of the application of the Hapke's theory in order to create synthetic spectra aimed at fitting a selection of NIRS’ spectra. The analysis performed with the first method brought to an approximately homogeneous distribution of olivine content (60 ± 15% on average) on Itokawa's surface, with the exception of Sagamihara region, which has a slightly (up to 10%) lower olivine content. The second method brought to an average 60 ± 7.5% olivine content within 5 selected spectra, with the same reduction found in the spectrum from the Sagamihara region. All these values are in agreement with literature values on this topic, especially with the ones retrieved from particles sampled in Muses Sea by the Hayabusa probe

Italy\u2019s functional \u2018health federalism\u2019 and dysfunctional cooperation

Analysis of the impact of the Covid-19 pandemic on the Italian regional system and of the performance of the different tiers of government in fighting the pandemi