10 resultados para non-thermal technologies
em AMS Tesi di Laurea - Alm@DL - Università di Bologna
Resumo:
Large-scale structures can be considered an interesting and useful "laboratory" to better investigate the Universe; in particular the filaments connecting clusters and superclusters of galaxies can be a powerful tool for this intent, since they are not virialised systems yet. The large structures in the Universe have been studied in different bands, in particular the present work takes into consideration the emission in the radio band. In the last years both compact and diffuse radio emission have been detected, revealing to be associated to single objects and clusters of galaxies respectively. The detection of these sources is important, because the radiation process is the synchrotron emission, which in turn is linked to the presence of a magnetic field: therefore studying these radio sources can help in investigating the magnetic field which permeates different portions of space. Furthermore, radio emission in optical filaments have been detected recently, opening new chances to further improve the understanding of structure formation. Filaments can be seen as the net which links clusters and superclusters. This work was made with the aim of investigating non-thermal properties in low-density regions, looking for possible filaments associated to the diffuse emission. The analysed sources are 0917+75, which is located at a redshift z = 0.125, and the double cluster system A399-A401, positioned at z = 0.071806 and z = 0.073664 respectively. Data were taken from VLA/JVLA observations, and reduced and calibrated with the package AIPS, following the standard procedure. Isocountour and polarisation maps were yielded, allowing to derive the main physical properties. Unfortunately, because of a low quality data for A399-A401, it was not possible to see any radio halo or bridge.
Resumo:
Radio relics are diffuse synchrotron sources generally located in the peripheries of galaxy clusters in merging state. According to the current leading scenario, relics trace gigantic cosmological shock waves that cross the intra-cluster medium where particle acceleration occurs. The relic/shock connection is supported by several observational facts, including the spatial coincidence between relics and shocks found in the X-rays. Under the assumptions that particles are accelerated at the shock front and are subsequently deposited and then age downstream of the shock, Markevitch et al. (2005) proposed a method to constrain the magnetic field strength in radio relics. Measuring the thickness of radio relics at different frequencies allows to derive combined constraints on the velocity of the downstream flow and on the magnetic field, which in turns determines particle aging. We elaborate this idea to infer first constraints on magnetic fields in cluster outskirts. We consider three models of particle aging and develop a geometric model to take into account the contribution to the relic transverse size due to the projection of the shock-surface on the plane of the sky. We selected three well studied radio relics in the clusters A 521, CIZA J2242.8+5301 and 1RXS J0603.3+4214. These relics have been chosen primarily because they are almost seen edge-on and because the Mach number of the shock that is associated with these relics is measured by X-ray observations, thus allowing to break the degeneracy between magnetic field and downstream velocity in the method. For the first two clusters, our method is consistent with a pure radiative aging model allowing us to derive constraints on the relics magnetic field strength. In the case of 1RXS J0603.3+4214 we find that particle life-times are consistent with a pure radiative aging model under some conditions, however we also collect evidences for downstream particle re-acceleration in the relic W-region and for a magnetic field decaying downstream in its E-region. Our estimates of the magnetic field strength in the relics in A 521 and CIZA J2242.8+5301 provide unique information on the field properties in cluster outskirts. The constraints derived for these relics, together with the lower limits to the magnetic field that we derived from the lack of inverse Compton X-ray emission from the sources, have been combined with the constraints from Faraday rotation studies of the Coma cluster. Overall results suggest that the spatial profile of the magnetic field energy density is broader than that of the thermal gas, implying that the ε_th /ε_B ratio decreases with cluster radius. Alternatively, radio relics could trace dynamically active regions where the magnetic field strength is biased high with respect to the average value in the cluster volume.
Resumo:
This thesis explores the X-ray nuclear and extended properties of the radio galaxy 3C 277.3, where a recent optical observation performed with the multi-unit spectroscopic explorer (MUSE) has revealed star-forming regions triggered by the propagation of non-thermal plasma in the intergalactic medium. This work aims to study the nuclear engine and its environment and, possibly, discover signatures of non-thermal plasma-gas interaction at high energies. 3C 277.3 was observed with the Chandra satellite five times from 2010 to 2014 for a total of about 200 ks. Data in the Chandra public archive were retrieved and analyzed. When necessary, the different pointings were combined to improve the signal-to-noise ratio. A detailed analysis of the Chandra image (obtained by combining all the observations) has revealed several emission regions. In addition to a bright nucleus, two jet knots and the northern hot spot were clearly detected by overlapping the X-ray data to a VLA map of the source at 1.4 GHz. An X-ray spectral analysis was performed for all these structures. Finally, the X-ray image was over-imposed on the MUSE data.
Resumo:
Flaring has been widely used in the upstream operation of the oil and gas industry, both onshore and offshore. It is considered a safe and reliable way to protect assets from overpressure and the environment from toxic gas using combustion. However, there are drawbacks to using flares, such as vibration and thermal radiation. Excessive contact with thermal radiation is harmful to offshore personnel and equipment. Research organizations and companies have invested time and money to combat this. Many technologies have been developed so far to reduce the risk of thermal radiation, one of them being the water curtain system. Several tests were done to see the effectiveness of the water curtain system in mitigating thermal radiation in an offshore environment. Each test varied in the flare output, wind speed, and the size of water droplets size of the water curtain. Later, the results of each test were compared and analyzed. The results showed that a water curtain system could be a solution to excessive thermal radiation that comes from an offshore flare. Moreover, the water curtain with smaller water droplets diameter gives a more favorable result in reducing thermal radiation. These results suggest that, although it offers simplicity and efficiency, designing an efficient water curtain system requires deep study. Various conditions, such as wind speed, flare intensity, and the size of the water droplets, plays a vital role in the effectiveness of the water curtain system in attenuating thermal radiation.
Resumo:
Il Diabete, modello paradigmatico delle malattie croniche, sta assumendo negli ultimi anni le proporzioni di una pandemia, che non ha intenzione di arrestarsi, ma del quale, con l’aumento dei fattori di rischio, aumentano prevalenza e incidenza. Secondo stime autorevoli il numero delle persone con diabete nel 2035 aumenterà fino a raggiungere i 382 milioni di casi. Una patologia complessa che richiede lo sforzo di una vasta gamma di professionisti, per ridurre in futuro in maniera significativa i costi legati a questa patologia e nel contempo mantenere e addirittura migliorare gli standard di cura. Una soluzione è rappresentata dall'impiego delle ICT, Information and Communication Technologies. La continua innovazione tecnologica dei medical device per diabetici lascia ben sperare, dietro la spinta di capitali sempre più ingenti che iniziano a muoversi in questo mercato del futuro. Sempre più device tecnologicamente avanzati, all’avanguardia e performanti, sono a disposizione del paziente diabetico, che può migliorare tutti processi della cura, contenendo le spese. Di fondamentale importanza sono le BAN reti di sensori e wearable device, i cui dati diventano parte di un sistema di gestione delle cure più ampio. A questo proposito METABO è un progetto ICT europeo dedicato allo studio ed al supporto di gestione metabolica del diabete. Si concentra sul miglioramento della gestione della malattia, fornendo a pazienti e medici una piattaforma software tecnologicamente avanzata semplice e intuitiva, per aiutarli a gestire tutte le informazioni relative al trattamento del diabete. Innovativo il Clinical Pathway, che a partire da un modello Standard con procedimenti semplici e l’utilizzo di feedback del paziente, viene progressivamente personalizzato con le progressive modificazioni dello stato patologico, psicologico e non solo. La possibilità di e-prescribing per farmaci e device, e-learning per educare il paziente, tenerlo sotto stretto monitoraggio anche alla guida della propria auto, la rendono uno strumento utile e accattivante.
Resumo:
Altough nowadays DMTA is one of the most used techniques to characterize polymers thermo-mechanical behaviour, it is only effective for small amplitude oscillatory tests and limited to a single frequency analysis (linear regime). In this thesis work a Fourier transform based experimental system has proven to give hint on structural and chemical changes in specimens during large amplitude oscillatory tests exploiting multi frequency spectral analysis turning out in a more sensitive tool than classical linear approach. The test campaign has been focused on three test typologies: Strain sweep tests, Damage investigation and temperature sweep tests.
Resumo:
A really particular and innovative metal-polymer sandwich material is Hybrix. Hybrix is a product developed and manufactured by Lamera AB, Gothenburg, Sweden. This innovative hybrid material is composed by two relatively thin metal layers if compared to the core thickness. The most used metals are aluminum and stainless steel and are separated by a core of nylon fibres oriented perpendicularly to the metal plates. The core is then completed by adhesive layers applied at the PA66-metal interface that once cured maintain the nylon fibres in position. This special material is very light and formable. Moreover Hybrix, depending on the specific metal which is used, can achieve a good corrosion resistance and it can be cut and punched easily. Hybrix architecture itself provides extremely good bending stiffness, damping properties, insulation capability, etc., which again, of course, change in magnitude depending in the metal alloy which is used, its thickness and core thickness. For these reasons nowadays it shows potential for all the applications which have the above mentioned characteristic as a requirement. Finally Hybrix can be processed with tools used in regular metal sheet industry and can be handled as solid metal sheets. In this master thesis project, pre-formed parts of Hybrix were studied and characterized. Previous work on Hybrix was focused on analyze its market potential and different adhesive to be used in the core. All the tests were carried out on flat unformed specimens. However, in order to have a complete description of this material also the effect of the forming process must be taken into account. Thus the main activities of the present master thesis are the following: Dynamic Mechanical-Thermal Analysis (DMTA) on unformed Hybrix samples of different thickness and on pre-strained Hybrix samples, pure epoxy adhesive samples analysis and finally moisture effects evaluation on Hybrix composite structure.
Resumo:
Due to the low cost, lightness and flexibility, Polymer Solar Cell (PSC) technology is considered one of the most promising energy technologies. In the past decades, PSCs using fullerenes or fullerene derivatives as the electron acceptors have made great progress with best power conversion efficiency (PCE) reaching 11%. However, fullerene type electron acceptors have several drawbacks such as complicated synthesis, a low light absorption coefficient and poor tuning in energy levels, which prevent the further development of fullerene-based PSCs. Hence the need to have a new class of electron acceptors as an alternative to conventional fullerene compounds. Non-fullerene acceptors (NFAs) have developed rapidly in the last years and the maximum PCEs have exceeded 14% for single-junction cells and 17% for double-junction tandem cells. By combining an electron-donating backbone, generally with several fused rings with electron-withdrawing units, we can simply construct NFA of the acceptor–donor–acceptor type (A–D–A). Versatile molecular structures have been developed using methods such as acceptor motif engineering and donor motif engineering. However, there are only a few electron-donating backbones that have been proved to be successful. Therefore, it is still necessary to develop promising building blocks to further enrich the structural diversity. An indacenodithiophene (IDT) unit with just five fused rings has a sufficiently rigid coplanar structure, which has been regarded as one of the promising electron-rich units to design high-performance A–D–A NFAs. In this work, performed at the King Abdullah University of Science and Technology in Saudi Arabia, a new nine-cyclic building block (TBIDT) with a two benzothiophene unit was synthesized and used for designing new non-fullerene electron acceptors.
Resumo:
Throughout the years, technology has had an undeniable impact on the AVT field. It has revolutionized the way audiovisual content is consumed by allowing audiences to easily access it at any time and on any device. Especially after the introduction of OTT streaming platforms such as Netflix, Amazon Prime Video, Disney+, Apple TV+, and HBO Max, which offer a vast catalog of national and international products, the consumption of audiovisual products has been on a constant rise and, consequently, the demand for localized content too. In turn, the AVT industry resorts to new technologies and practices to handle the ever-growing workload and the faster turnaround times. Due to the numerous implications that it has on the industry, technological advancement can be considered an area of research of particular interest for the AVT studies. However, in the case of dubbing, research and discussion regarding the topic is lagging behind because of the more limited impact that technology has had on the very conservative dubbing industry. Therefore, the aim of the dissertation is to offer an overview of some of the latest technological innovations and practices that have already been implemented (i.e. cloud dubbing and DeepDub technology) or that are still under development and research (i.e. automatic speech recognition and respeaking, machine translation and post-editing, audio-based and visual-based dubbing techniques, text-based editing of talking-head videos, and automatic dubbing), and respectively discuss their reception by the industry professionals, and make assumptions about their future implementation in the dubbing field.
Resumo:
Instrument transformers serve an important role in the protection and isolation of AC electrical systems for measurements of different electrical parameters like voltage, current, power factor, frequency, and energy. As suggested by name these transformers are used in connection with suitable measuring instruments like an ammeter, wattmeter, voltmeter, and energy meters. We have seen how higher voltages and currents are transformed into lower magnitudes to provide isolation between power networks, relays, and other instruments. Reducing transient, suppressing electrical noises in sensitive devices, standardization of instruments and relays up to a few volts and current. Transformer performance directly affects the accuracy of power system measurements and the reliability of relay protection. We classified transformers in terms of purpose, insulating medium, Voltage ranges, temperature ranges, humidity or environmental effect, indoor and outdoor use, performance, Features, specification, efficiency, cost analysis, application, benefits, and limitations which enabled us to comprehend their correct use and selection criteria based on our desired requirements. We also discussed modern Low power instrument transformer products that are recently launched or offered by renowned companies like Schneider Electric, Siemens, ABB, ZIV, G&W etc. These new products are innovations and problem solvers in the domain of measurement, protection, digital communication, advance, and commercial energy metering. Since there is always some space for improvements to explore new advantages of Low power instrument transformers in the domain of their wide linearity, high-frequency range, miniaturization, structural and technological modification, integration, smart frequency modeling, and output prediction of low-power voltage transformers.