Optical processor based on a-SiC technology for spectral data error control

The SiC optical processor for error detection and correction is realized by using double pin/pin a-SiC:H photodetector with front and back biased optical gating elements. Data shows that the background act as selector that pick one or more states by splitting portions of the input multi optical signals across the front and back photodiodes. Boolean operations such as exclusive OR (EXOR) and three bit addition are demonstrated optically with a combination of such switching devices, showing that when one or all of the inputs are present the output will be amplified, the system will behave as an XOR gate representing the SUM. When two or three inputs are on, the system acts as AND gate indicating the present of the CARRY bit. Additional parity logic operations are performed by use of the four incoming pulsed communication channels that are transmitted and checked for errors together. As a simple example of this approach, we describe an all optical processor for error detection and correction and then, provide an experimental demonstration of this fault tolerant reversible system, in emerging nanotechnology.

Nanoparticles based Permeable Reactive Barriers as an Eco-efficient Technology for nitrate remediation in soil and groundwater

The need to increase agricultural yield led, among others, to an increase in the consumption of nitrogen based fertilizers. As a consequence, there are excessive concentrations of nitrates, the most abundant of the reactive nitrogen (Nr) species, in several areas of the world. The demographic changes and projected population growth for the next decades, and the economic shifts which are already shaping the near future are powerful drivers for a further intensification in the use of fertilizers, with a predicted increase of the nitrogen loads in soils. Nitrate easily diffuses in the subsurface environments, portraying high mobility in soils. Moreover, the presence of high nitrate loads in water has the potential to cause an array of health dysfunctions, such as methemoglobinemia and several cancers. Permeable Reactive Barriers (PRB) placed strategically relatively to the nitrate source constitute an effective technology to tackle nitrate pollution. Ergo, PRB avoid various adverse impacts resulting from the displacement of reactive nitrogen downstream along water bodies. A four stages literature review was carried out in 34 databases. Initially, a set of pertinent key words were identified to perform the initial databases searches. Then, the synonyms of those initial key words were used to carry out a second set of databases searches. The third stage comprised the identification of other additional relevant terms from the research papers identified in the previous two stages. Again, databases searches were performed with this third set of key words. The final step consisted of the identification of relevant papers from the bibliography of the relevant papers identified in the previous three stages of the literature review process. The set of papers identified as relevant for in-depth analysis were assessed considering a set of relevant characterization variables.

Development of new methodologies in sample treatment for proteomics workflow based on enzymatic probe sonication technology and mass spectrometry

Thesis submitted to the Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia, for the degree of Doctor of Philosophy in Biochemistry

Decision making processes based on innovation indicators: which implications for technology assessment?

Based on the report for “Project IV” unit of the PhD programme on Technology Assessment. This thesis research has the supervision of António Moniz (FCT-UNL and ITAS-KIT) and Manuel Laranja (ISEG-UTL). Other members of the thesis committee are Stefan Kuhlmann (Twente University), Leonhard Hennen (Karlsruhe Institute of Technology-ITAS), Tiago Santos Pereira (Universidade de Coimbra/CES) and Cristina Sousa (FCT-UNL).

Video interaction using pen-based technology

Dissertação para obtenção do Grau de Doutor em Informática

UAV - based imagery processing using structure from motion and remote sensing technology

With the recent advances in technology and miniaturization of devices such as GPS or IMU, Unmanned Aerial Vehicles became a feasible platform for a Remote Sensing applications. The use of UAVs compared to the conventional aerial platforms provides a set of advantages such as higher spatial resolution of the derived products. UAV - based imagery obtained by a user grade cameras introduces a set of problems which have to be solved, e. g. rotational or angular differences or unknown or insufficiently precise IO and EO camera parameters. In this work, UAV - based imagery of RGB and CIR type was processed using two different workflows based on PhotoScan and VisualSfM software solutions resulting in the DSM and orthophoto products. Feature detection and matching parameters influence on the result quality as well as a processing time was examined and the optimal parameter setup was presented. Products of the both workflows were compared in terms of a quality and a spatial accuracy. Both workflows were compared by presenting the processing times and quality of the results. Finally, the obtained products were used in order to demonstrate vegetation classification. Contribution of the IHS transformations was examined with respect to the classification accuracy.

Indoor location-based analytics systems: Portuguese market compettive assessment and entry procing strategy of BIPs' technology in Sonae Sierra Shopping malls stores

This project attempts to provide an in-depth competitive assessment of the Portuguese indoor location-based analytics market, and to elaborate an entry-pricing strategy for Business Intelligence Positioning System (BIPS) implementation in Portuguese shopping centre stores. The role of industry forces and company’s organizational resources platform to sustain company’s competitive advantage was explored. A customer value-based pricing approach was adopted to assess BIPS value to retailers and maximize Sonae Sierra profitability. The exploratory quantitative research found that there is a market opportunity to explore every store area types with tailored proposals, and to set higher-than-tested membership fees to allow a rapid ROI, concluding there are propitious conditions for Sierra to succeed in BIPS store’s business model in Portugal.

In vivo measurements of atrial repolarization alternans based on standard pacemaker technology

It has been shown that repolarization alternans, a beat-to-beat alternation in action potential duration, enhances dispersion of repolarization above a critical heart rate and promotes susceptibility to ventricular arrhythmias. It is unknown whether repolarization alternans is measurable in the atria using standard pacemakers and whether it plays a role in promoting atrial fibrillation. In this work, atrial repolarization alternans amplitude and periodicity are studied in a sheep model of pacing-induced atrial fibrillation. Two pacemakers, each with one right atrial and ventricular lead, were implanted in 4 male sheep after ablation of the atrioventricular junction. The first one was used to deliver rapid pacing for measurements of right atrial repolarization alternans and the second one to record a unipolar electrogram. Atrial repolarization alternans appeared rate-dependent and its amplitude increased as a function of pacing rate. Repolarization alternans was intermittent but no periodicity was detected. An increase of repolarization alternans preceding episodes of non-sustained atrial fibrillation suggests that repolarization alternans is a promising parameter for assessment of atrial fibrillation susceptibility.

Catalytic gates for gas sensors based on SiC technology

En este trabajo se presenta un estudio químico y estructural de las capas metálicas de Pt y TaSix utilizadas como puerta catalítica en sensores de gas de alta temperatura basados en dispositivos MOS de SiC. Para ello se han depositado capas de diferentes espesores sobre substratos de Si. Los resultados muestran que con la reducción del espesor de Pt y con un recocido se consigue aumentar la rugosidad de las capas de puerta, lo que debería aumentar la sensibilidad y la velocidad de respuesta de los dispositivos que las incorporasen. Otro efecto del recocido es la transformación química del material de la puerta que, para capas delgadas de Pt con TaSix, produce la transformación total Pt en Pt2Ta, lo que podría afectar a las características catalíticas de la puerta. Los primeros resultados eléctricos indican que, a pesar de que las capas de Pt empleadas son gruesas y compactas, los diodos MOS túnel de SiC son sensibles a los gases CO y NO2, aunque presentan una velocidad de respuesta bastante lenta.

Features of a Ziegler-Natta catalyst prepared with the Sirius emulsion-based catalyst production technology

Traditionellt har man ansett att Ziegler-Natta katalysatorer för framställning av polypropen bör ha stor inre yta och hög porositet för att ge hög aktivitet och bra polymerpartikelmorfologi. Den av Borealis utvecklade Sirius emulsionsbaserade katalysatortillverkningsteknologin ger katalysatorer utan mätbar inre yta och porositet. Katalysatorn ger, trots sin kompakthet, polymerpartiklar med utmärkt morfologi och har hög aktivitet. Sirius katalysatorns prestanda, beträffande polymerisationskinetik och polymerstruktur, undersöktes i detta doktorsarbete. En jämn och kontrollerad tidig fragmentering av katalysatorn är av största vikt för att uppnå bra partikelmorfologi i en kommersiell process. Det visades att fragmenteringen av Sirius katalysatorn under de första sekunderna och minuterna av reaktionen framskred på ett homogent sätt. Oligomerhalten i den slutliga produkten är viktig i många applikationer, tex. i applikationer där polymeren kommer i kontakt med mat. Polymerer producerade med Sirius katalysatorn hade en låg oligomerhalt på grund av den smala molekylviktsfördelningen. Analys av kedjeändorna avslöjade att Sirius katalysatorn hade en hög frekvens av kedjeöverföring till monomer, vilket förklarade Sirius katalysatorns något begränsade förmåga att producera polymerer med hög molekylvikt. Sampolymerer av propen och eten producerade med Sirius uppvisade jämnare eten fördelning mellan långa och korta kedjor samt en mera randomiserad fördelning av eten längs med kedjorna än med den konventionella referenskatalysatorn. Tillsammans med den smala molekylviktsfördelningen indikerade resultaten att fördelningen av typer av aktiva centrum i Sirius katalysatorn är smal. Då man producerar polypropen med hög slagseghet skall polymerpartiklarna ha hög porositet för att kunna ackumulera eten/propen gummit. SiO2 nanopartiklar tillsatta under framställningen av Sirius katalysatorn ökade polymerpartikelns porositet, vilket möjliggjorde en dramatisk ökning av gummihalten.

Science and technology of rubber reclamation with special attention to NR-based waste latex products

A comprehensive overview of reclamation of cured rubber with special emphasis on latex reclamation is depicted in this paper. The latex industry has expanded over the years to meet the world demands for gloves, condoms, latex thread, etc. Due to the strict specifications for the products and the unstable nature of the latex as high as 15% of the final latex products are rejected. As waste latex rubber (WLR) represents a source of high-quality rubber hydrocarbon, it is a potential candidate for generating reclaimed rubber of superior quality. The role of the different components in the reclamation recipe is explained and the reaction mechanism and chemistry during reclamation are discussed in detail. Different types of reclaiming processes are described with special reference to processes, which selectively cleave the cross links in the vulcanized rubber. The state-of-the-art techniques of reclamation with special attention on latex treatment are reviewed. An overview of the latest development concerning the fundamental studies in the field of rubber recycling by means of low-molecular weight compounds is described. A mathematical model description of main-chain and crosslink scission during devulcanization of a rubber vulcanizate is also given.