Annual report 2009 // Institute of Radiochemistry

[no abstract available

Designing virtual spaces: redefining radio art through digital control

Radio Art is a composition practice that is constantly evolving. Artists share a commonality to redefine, reinvent, and repurpose analogue radio. It is an art that often bends to the will of antiqued technology, celebrating a wide pallet of found sounds. This research extends the boundaries of the art form by exploring Radio Art through sonic-centric lens and establishing a consistent and reproducible compositional framework. By shifting radio from a found object to an instrument, I have deconstructed its sonic aesthetics into two parallel materials for composition, gestural noise and broadcast signal. When tuning an analogue radio to a signal, relationships between these materials unfold. Contrast is a term found throughout my research. Contrast is embodied throughout radio and its history; radio is used as both a scientific communication device and for artistic expression. it is a symbol of democracy and oppression. Radio produces broadcast noise and signal, creating poetic reception, such as control and chaos, anxiety and ecstasy, distance and closeness. This research explores the characteristics of these forces and materials as a symbiotic relationship of unfolding radiophonic behaviours. A major focus of this research is the control of analogue radio through deconstruction and composition. I embarked on a twenty-four-month development period to build a Digital Audio Workstation called Radiophonic Environmental Designer, (RED). RED enables composers to create virtual radiophonic environments that are navigated by rotating the dial. Material is positioned along a horizon, and tuning behaviours sculpted. There is also a physical interface embedded into an analogue radio shell to control the virtual tuning, namely, Broadcast Link-up Environment, (BLUE). BLUE is an ad-on program offering an online digital platform for the diffusion of Radio Art. Using an internet connection and gyroscope technology that is built into most smart phones, a radiophonic environment is interacted through a purpose-built website. In my creative practice, analogue radio has been redesigned by adopting digital technological practices to control, edit and model it’s unique sound. In doing so, I reflect upon relationships between analogue and digital design principles through an extensive study on virtual analogue software and interfaces

QoE estimation for Adaptive Video Streaming over LTE Networks

Η 4η γενιά (4G) κινητών επικοινωνιών, στην οποία ανήκει το σύστημα Long Term Evolution (LTE), παρέχει ευρυζωνική πρόσβαση σε κινητές συσκευές με ποιότητα και ταχύτητα που αγγίζουν τις ενσύρματες επικοινωνίες. Παρόλ’αυτά, η κινητικότητα εκ φύσεως εισάγει αστοχίες/διακυμάνσεις στην ασύρματη διεπαφή, γενόντας έτσι την ανάγκη για αντίστοιχη προσαρμογή της ροής μετάδοσης των δεδομένων. Η ανάγκη αυτή είναι ακόμη πιο έκδηλη για τις ροές δεδομένων βίντεο, που έχουν και τη μερίδα του λέοντος στην διαδικτυακή κίνηση. Καθώς, λοιπόν, η ροή βίντεο μέσω ΗΤΤΡ έχει γίνει ο κανόνας στη διανομήπεριεχομένου, η εφαρμογή ενός πρωτοκόλλου προσαρμογής βασισμένου στο HTTP είναι αναπόφευκτη. Το DASH (Dynamic Adaptive Streaming over HTTP) επιτρέπει μια ομαλή, αδιάκοπη ροή video εφαρμόζοντας αλγόριθμους προσαρμογής του bitrate στη μεριά του χρήστη αξιοποιώντας πλήρως την υπάρχουσα υποδομή. Έχοντας ως στόχο να τελειοποιήσουν την ποιότητα την οποία προσφέρει στους χρήστες το δίκτυο, οι ερευνητές συνεχώς αναπτύσσουν νέες φόρμουλες για την εκτίμηση της ποιότητας εμπειρίας του τελικού χρήστη, γνωστής υπο τον όρο Quality of Experience (QoE). Η παρούσα πτυχιακή αντιπροσωπεύει την προσπάθεια συγκερασμού των τριών ακόλουθων πυλώνων: της υποκείμενης υποδομής, του ελέγχου της ποιότητας υπηρεσίας με τη χρήση αλγορίθμων προσαρμογής και του επαναπροσδιορισμού του συστήματος με ανάλυση της ποιότητας και ανατροφοδότηση. Ανοίγει τη συζήτηση για τη χρήση προσαρμοζόμενης ροής μετάδοσης πάνω απο δίκτυα LTE και στοχεύει όχι μόνο να προσφέρει μια βαθιά βιβλιογραφική προσέγγιση των επιμέρους, αλλά και να περιγράψει πώς συνδέονται, πώς επικαλύπτονται, ή πώς αλληλεπιδρούν. Περιγράφει τα σημαντικότερα σύγχρονα μοντέλα μέτρησης QoE και πώς αυτά χρησιμεύουν στην αντικειμενική εκτίμηση της ποιότητας. Βασική συνεισφορά της εργασίας, είναι η ανάπτυξη μιάς πλήρης εκτελέσιμης οντότητας (module) για τον προσομοιωτή NS-3 συνδυάζοντας όλες τις έννοιες που αναφέρονται παραπάνω.Ο αναγνώστης μπορεί να βρεί ενα τυπικό παράδειγμα εκτέλεσης της εν λόγω οντότητας, με την συνοδεία μιας βήμα-βήμα εξήγησής του και και κάποιων διαγραμμάτων με αποτελέσματα. Το NS3 module αναπτύχθηκε με την ελπίδα να φανεί χρήσιμο σε κάθε ερευνητή τηλεπικοινωνιών που ασχολείται με θέματα παροχής ποιότητας εμπειρίας και αναζητά ένα εργαλείο προσομειώσεων.The ability to address an increasing need for mobility in work and entertainment has rendered LTE networks critically essential to our everyday environments. The promising 4th Generation (4G) of Long Term Evolution (LTE) provides ubiquitous broadband access to mobile devices matching land communications in speed and quality. However, the nature of mobility introduces a need for adaptivity in multimedia streaming, the largest part of mobile Internet traffic. As HTTP video streaming has become the de facto dominating solution to distribute media content, the implementation of an HTTP-based adaptive streaming protocol is inevitable. Dynamic Adaptive Streaming over HTTP (DASH) allows for smooth, uninterrupted video streaming by implementing bitrate adaptation algorithms on the client side, with complete utilization of the existing network infrastructure. In order to perfect the current quality served by the network, network researchers constantly develop new metrics to assess the end-user’s Quality of Experience. This thesis represents an attempt to join these three pillars of mobile video streaming: the underlying infrastructure, the over-the-top algorithmic quality control, and the follow-up feedback measurement. It opens a discussion about the use of adaptive streaming in LTE networks, and aims to offer not only a deep down bibliographic approach of each individual concept, but also describe where they overlap, how they connect and interact with each other. It depicts the most important contemporary QoE models and metrics, explains their formulas, and outlines their uses as key performance indicators in objective quality estimation. Furthermore, within this work, we provide a complete, expandable NS-3 model combining all the concepts discussed. An HTTP Server-Client model within the LTE network architecture, with implemented adaptive streaming functionality. The tool was developed in the hope of becoming useful to any telecommunications researcher, supporting their research and introducing them to the NS-3 simulator. In the end, we present a typical execution of our example with a step by step explanation, followed by the plotting of some of the results using a C++ script we developed

Promoting the high-quality recycling of plastics from demolition waste and enhancing the use of recycled materials in construction products in accordance with the European plastics strategy : final report

This study presents in detail: the use of plastic products and the opportunities for recyclate use in the construction sector, quantities of plastic used, take-back systems, recycling techniques, current recyclate use and plastic construction product packaging.Potentials for increasing high-quality recyclate use were identified. Existing hurdles and options for action for industry and politics are presented. Current recyclate use as well as its potential use are strongly dependent on the application area of plastics. The biggest hurdles for the use of recycled materials are product life time, dismantling and technical requirements

Advanced Technology of Waste Treatment

The protection of human health and the environment (representing the main reason for waste management), as well as the sustainable use of natural resources, requires chemical, biological, physical and thermal treatment of wastes. This refers to the conditioning (e.g., drying, washing, comminution, rotting, stabilization, neutralization, agglomeration, homogenization), conversion (e.g., incineration, pyrolysis, gasification, dissolution, evaporation), and separation (classification, direct and indirect (i.e., sensor-based) sorting) of all types of wastes to follow the principles of the waste hierarchy (i.e., prevention (not addressed by this issue), preparation for re-use, recycling, other recovery, and disposal). Longstanding challenges include the increase of yield and purity of recyclable fractions and the sustainable removal or destruction of contaminants from the circular economy.This Special Issue on “Advanced Technology of Waste Treatment” of Processes collects high-quality research studies addressing challenges on the broad area of chemical, biological, physical and thermal treatment of wastes

Different approaches to the development and use of carbon materials for water treatment purposes

Tese de doutoramento, Química (Química Tecnológica), Universidade de Lisboa, Faculdade de Ciências, 2018The work presented in this thesis consisted in the preparation of porous materials and in their application in adsorption processes of organic compounds in aqueous phase, and bacteria adhesion. After the theoretical introduction (Chapters II to VI), the results presented in Chapter VII correspond to the study centred in the preparation of activated carbons from an apple tree branches char by chemical activation with potassium carbonate and hydroxide, under different experimental conditions. The employed methodology allowed to obtain materials with a high global preparation yield and to reduce the volatile content of the precursor. The activated carbons synthesized with potassium carbonate and hydroxide present a highly developed porosity, with high micropore volumes and specific surface areas (values up to 1920 cm3 g-1 and 2445 cm3 g-1, respectively). The impact of activation on the morphology of the carbons was evaluated by scanning electron microscopy and it was observed that the more severe activation with KOH led to a higher consumption of the carbonaceous matrix and an homogenization of the particle size, in comparison to the activation with carbonate. The performance of the materials in the adsorption of the pharmaceutical compounds atenolol and tiamulin hydrogen fumarate was comparable and better than that of the commercial samples tested. The carbons with higher adsorption capacity were the KOH activated samples, which allowed for the removal of 556 mg g-1 of atenolol and of approximately 250 mg g-1 of tiamulin, in equilibrium conditions. The supermicropores volume was important for atenolol adsorption and some impact of the carbons’s surface chemistry on the process was observed. The adsorption of the antibiotic tiamulin also occurred on the supermicropores of the solids and the mesopore volume of carbon NS facilitated its diffusion. In Chapter VIII the performance of activated carbons with different morphologies in the adsorption of two organic pollutants was assessed, and the role of morphology in thermal treatment regeneration processes was evaluated. The activated carbon cloth was characterized in terms of texture, morphology and surface chemistry, together with commercial samples in the granular and powdered forms. The carbon felt presents an open structure composed by fibres of high diameter. The porosity of this solid revealed to be mostly composed by supermicropores easily accessible at the surface of the material fibres. The carbons were tested in liquid phase adsorption experiments for the removal of paracetamol and clofibric acid. The diffusion of these species was facilitated in the cloth because the micropores are at the matrix surface, and in carbon NS due to the high mesopore volume. Both pollutants were efficiently adsorbed by the solids up to maximum adsorbed quantities of 323 mg g-1 and 568 mg g-1 of paracetamol and clofibric acid, respectively. Regeneration by thermal treatment was studied in cyclic saturation-regeneration assays. The more moderate conditions of regeneration (heating at 400 ºC during 1 h) were more efficient in recovering the porosity of the samples. The regeneration treatment was more efficient in the case of the cloth and granular carbon that retained some porosity and approximately 50 % of the initial adsorption capacity up to the third reuse.In regards to the study of bacteria adhesion of Escherichia coli cells in activated carbons, the results in Chapter IX reveal that the powdered carbon had a clear better performance removing up to 4log of cells per cm3 of suspension after 48 h of contact time. The adhesion mechanism in this solid seems to occur in two stages: an initial adhesion favoured by attractive electrostatic interactions, and immobilization of bacteria cells due to the formation of carbon-cell-cell carbon agglomerates. No adhesion of microorganisms occurred on the oxidized sample, suggesting that the establishment of initial repulsive interactions was sufficient to avoid colonization of the sample. The formation of cell + carbon structures was more difficult when the carbon particles were saturated with caffeine. At last, in the study reported in Chapter X, tannin polymers obtained from Mimosa tree bark were characterized, and the potential of the materials as adsorbents of several organic compounds in aqueous phase was evaluated. The use of higher surfactant amounts promoted the formation of wider mesopores and lower phenolic content. One of the samples was washed with a hydrochloric acid solution, and the treatment caused a slight widening of the mesopores with some porous volume loss, and without loss in phenolic content. A detailed study of methylene blue adsorption in aqueous phase was performed, and then the materials were tested for the removal of a set of pharmaceutical compounds and a plasticizer, highly consumed worldwide. The two tested samples showed adsorbent properties removing up to a maximum amount of 152 mg g-1 of pollutant, in equilibrium conditions. The good performance of the polymers was attributed at a great extent to the aromatic character of the materials. The molecular species with smaller molar volume, and with lower width were adsorbed in higher amounts suggesting a packing of the species in the polymers mesopores