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Desenvolvimento de cerâmicas refratárias engenheiradas densas e porosas
(Universidade Federal de São Carlos, 2019-09-04) Pelissari, Pedro Ivo Batistel Galiote Brossi; Pandolfelli, Victor Carlos; https://lattes.cnpq.br/7369376873984839; https://lattes.cnpq.br/1402623804537094
High temperature processes are of great importance as they are widely applied in the manufacture of commodities, consumer goods and advanced materials. For these processes to be possible, the thermal environment in which they occur must consist of materials with special features, called refractories, for which their structure at different scales, nano to micro, influence directly their thermal and mechanical performance. The development of high-performance advanced refractory ceramics has been using techniques of theoretical modelling of the materials properties in order to correlate these features, making it possible to improve their performance. This trend is based on the use of computational tools, such as numerical simulation, to evaluate the impact of different structural characteristics on the properties of materials. Thus, the main goal of the present thesis was to use different numerical methods in order to assist the microstructure design of refractory materials for structural and thermal insulation applications. The impact of different microstructural descriptors, such as pore size and distribution, was evaluated for the thermal and mechanical properties of thermal insulating ceramic foams. It was observed the existence of an optimum pore size in the 0.5 to 3.0 m, range which reduces the effective thermal conductivity of these materials to a minimum for temperatures above 1000 °C. In the case of structural materials, it was also developed a bioinspired refractory with engineered microstructure presenting high mechanical performance at room (σf = 672.0 MPa and KIC = 7.4 MPa. m1/2) and high temperature (σf = 350.0 MPa and KIC = 6.0 MPa. m1/2), 1200 °C. The development and characterization of this latest material was carried out in conjunction with the Zurich Federal Institute of Technology (ETHz) and Imperial College London. Additionally, thermo-optical simulations were used to evaluate the thermal performance of these structures for a likely application as thermal barriers.
Packet routing analyses using probabilistic data structures in Multi-Tenant Networks based on programmable devices
(Universidade Federal de São Carlos, 2019-09-04) Teles Martins, Regis Francisco; Villaça, Rodolfo; https://lattes.cnpq.br/3755692723547807; Verdi, Fábio Luciano; https://lattes.cnpq.br/9143186843657940; https://lattes.cnpq.br/6385377117129215
Given the network traffic growth, due to applications that heavily use computational cloud infrastructure, the need for improving the monitoring traffic techniques has increased. For traffic engineering, it is essential to gain total visibility into the traffic flowing across the network. The most used methods for traffic monitoring in the industry are those based on dedicated monitoring protocols as SNMP (Simple Network Management Protocol), NetFlow, SFlow, among others. With processing capacity evolution of forwarding devices, new techniques have been proposed. The use of sketches has become widely popular for traffic monitoring tasks. Sketches are compact data structures capable of summarizing and store information about the state of packets. Using sketches, it is possible to monitor a network traffic, understanding the path travelled by each packet and which devices were responsible for the packet forwarding. Analyzing traffic over the network is a challenge that changes the traditional monitoring approach. The current performance indicator metrics provided by network devices are not enough to analyze and create insights for the network traffic as a whole. We need a way to produce key performance indicators that can be correlated across different network devices on the same network. This new approach opens opportunities for researching and developing novel techniques to obtain a holistic network traffic visibility, to support decisions in traffic engineering, to detect traffic anomalies and other applications. Using a single sketch named BitMatrix, proposed in this work, it is possible to monitor network traffic, understand the path travelled per packet and which devices forwarded this packet along its path. In this context, this probabilistic structure was adopted to identify the path used to forward a packet in a multi-tenant network in two different scenarios: a) in an emulated network, using P4 routers and, b) in a simulated network, processing real traffic traces, using a Python framework. As a result, overloaded routers, links and paths and heavy user tenants were identified.
Estrutura e qualidade ambiental dos riachos costeiros na ictiofauna e suas redes tróficas de uma região neotropical
(Universidade Federal de São Carlos, 2019-09-04) Santos, João Alberto Paschoa dos; Moura, Evelise Nunes Fragoso de; https://lattes.cnpq.br/6561803596789261; Peret, Alberto Carvalho; https://lattes.cnpq.br/0995579236780271; https://lattes.cnpq.br/2499478646835333
To determine the composition, distribution and trophic relations between fish species in streams located in Bertioga-SP sandbank and to evaluate if the environmental characteristics influence this system are the main objectives of this thesis. Fish from 11 clearwater and darkwater streams were sampled using electric fishing over a year. The stomachs of the 11 most abundant species of the 26 species recorded throughout the study were analyzed. The unique species of clearwater streams were Acentronichthys leptos, Characidium japuhibense, Characidium lanei, Kronichthys cf. heylandi, Pseudotothyris obtusa, Rhamdioglanis frenatus, in addition to the marine / estuarine species Awaous tajasica, Centropomus parallelus and Dormitator maculatus, while only Hyphessobrycon bifasciatus was unique in blackwater environments. The trophic webs were similar in the streams comparing the dry and rainy periods. Allochthonous and autoctone organic material was similarly consumed among fish species, showing no preference for origin. The species with the highest number of relationships were Gymnotus pantherinus, Mimagoniates microlepis and Hollandichthys multifasciatus. Spintherobolus broccae is endangered. Thus, the preservation of the Conservation Units Serra do Mar State Park and Restinga de Bertioga State Park are important, as they are home to species that were important for the energy relations in the nutrient cycling of the system, besides being an important region with a wide diversity and thus providing relevant ecosystem services.