Este trabalho tem por objetivo estudar o aproveitamento do pó de aciaria elétrica (PAE) na sinterização de minério de ferro visando a eliminação de zinco. Primeiramente, foi feita uma caracterização física e química do resíduo através de análises químicas, granulométricas, morfológicas e de difração de raios-X. O minério de ferro, principal componente do processo de sinterização, foi caracterizado através de análise química, granulométrica e de umidade. Em seguida, foram fabricadas micropelotas de 3,0 a 5,0mm de diâmetro compostas por 70% de PAE e 30% de moinha de coque, que foram classificadas por peneiramento e secas em esfufa. Depois de aglomerado, o resíduo foi incorporado na sinterização de minério de ferro em diferentes proporções, condições de processo e formas de adição (micropelotas, undersize da micropelotização com granulometria entre 1,0 e 2,0mm, ou mistura de PAE e coque em pó). A cada processo de sinterização foram retiradas amostras de sínter, os materiais foram analisados através de Microscópio Eletrônico de Varredura (MEV), macroscopia e análises químicas por espectrofotometria de absorção atômica para verificar o teor de zinco. Amostras de misturas não sinterizadas também foram submetidas a análises químicas para determinar a quantidade inicial de zinco, ou seja, verificar a quantidade de zinco contido na mistura antes do processo de sinterização. Mediante a comparação do teor de zinco das amostras não sinterizadas com os sínteres, foi possível determinar a eliminação de zinco nos ensaios realizados. Aproximadamente 92% de zinco foi eliminado (junto com os gases de saída) com a incorporação de 10% de micropelotas na mistura a sinterizar. Os resultados mostraram que a eliminação do metal no processo é proporcional à relação redutor/resíduo. / The aim of this work was to study the use of electric arc furnace dust (EAFD) in iron ore sintering process aiming zinc elimination. Firstly, physical and chemical characterizations of the waste were made using X-ray diffraction, microscopy, chemical and size analyses. Iron ore is the main component of the sintering process, this material was characterized by chemical, size and humidity analyses. After, micropellets composed of EAFD 70% and coke breeze 30% with diameters of 3.0-5.0 mm were produced, then they were dried in kiln and classified by sieving. The pellets were incorporated into the iron ore sintering charge using differents proportions, process conditions and addition forms (micropellets, undersize with diameters of 1.0-2.0 mm, or a mixture of EAFD and coke breeze). Sintered samples were collected in each sintering process. These materials were analyzed by scanning electron microscopy (SEM), macroscopy and chemical analysis using atomic absorption spectrophotometry in order to determine the zinc content. Samples of not sintered mixtures were also characterized by chemical analysis aiming the determination the initial amounts of zinc, i.e. in order to check the zinc amounts present in the mixture before the sintering process. The comparation between the zinc contents of sintered samples and not sintered allowed to determine the elimination of zinc during the experiments. About 92% of zinc was eliminated (along with the output gas) with the incorporation of 10% of micropellet in the sintering mixture. Results showed that the zinc elimination in the process is proportional to the ratio reducer/waste.

Due to the rapid development of telecommunication devices, operating speeds are getting faster and more power is being consumed by those devices. Therefore, there is a big concern on how to prolong the battery life in order to fit consumers’ needs. Power amplifiers (PA) at the front end of wireless equipment have drawn a big concern from engineers because of their large power consumption in the system. There is a lot research conducted on PA solutions for improving power-added efficiency (PAE) of amplifiers. PAE is a figure of merit representing how efficient the PA converts DC power to RF power. With PAE increased, the device is able to output the same amount of power with less DC power consumed. Non-linear Class-F and Class-F-1 PAs have drawn the most attention among all different classes of PAs from engineers because of their capability of outputting high power and providing good PAE. Class-F boosts up PAE by controlling the harmonic content at the output. Advanced Design System (ADS) from Agilent is used for design and simulation based on the ADS model of Cree’s CGH40010 high electron mobility transistor (HEMT). A high efficiency power amplifier is fabricated on RT/duroid 5870 high frequency laminate board. In this design, the harmonics at the input are controlled as well as the harmonics at the output. An input wave-shaping network is designed to shape the waveforms at the gate. In this case, the PAE is boosted 30% higher than the PA with only the output wave-shaping network. By terminating harmonics with proper impedances at the output, a square voltage waveform and a half-sine current waveform are obtained at the transistor drain terminal. The overlapping area between the voltage and current waveforms can be reduced as well as the active device power consumption. The final design operating at 1GHz produced a PAE of 89% with 38.35dBm output power in simulation and PAE of 78% with 38.7dBm output power as the result of the IEEE PA design contest. The thesis has shown the effectiveness of the Class-F PA to boost up PAE by preventing the 2nd and 3rd harmonic power from delivering to the load and shaping the waveforms at the transistor terminals. It also shows the benefit of using radial stubs in wave-shaping networks over open-circuit stubs.

This thesis addresses the potential of implementing watt-level class-AB Power Amplifier (PA) for WLAN in 65 nm CMOS technology, at 2.4 GHz frequency. In total, five PAs have been compared, where the examined parameters were output power (Pout), linearity, power added efficiency (PAE), and area consumption. Four PAs were implemented using conventional cascode topology with different combination of transistors sizes in 65nm CMOS, and one PA using a high-voltage Extended Drain MOS (EDMOS) device, implemented in the same 65 nm CMOS with no process or mask changes. All schematics were created using Cadence Virtuoso CAD tools. The test benches were created using the Agilent's Advance Design System ( ADS) and simulated with the ADS-Cadence dynamic link. The simulation results show that the EDMOS PA (L=350 nm) has the smallest area, but has harder to reach the required Pout. Cascode no. 3 (L= 500,260 nm) has the best Pout (29.1 dBm) and PAE (49.5 %). Cascode no. 2 (L= 500,350 nm) has the best linearity (low EVM). Cascode no. 1 (L=500,500 nm) has low Pout (27.7 dBm). Cascode no.4 (L=500,60 nm) has very bad linearity. The thesis also gives an overview for CMOS technology, discusses the most important aspects in RF PAs design, such as Pout, PAE, gain, and matching networks. Different PA classes are also discussed in this thesis.

This thesis addresses the potential of implementing a predriver for class-D power amplifier for WLAN in 65 nm CMOS technology. In total, eight different predrivers have been created using Cadence Virtuoso CAD tools. All designs have been tested using Agilent's Advance Design System (ADS) and simulated using the ADS-Cadence dynamic link. Furthermore, a comparison between the eight designs and the reference design has been done. The examined parameters were output power (Pout), efficiency, and effective area consumption. The simulation results show that most of the proposed designs obtain higher output power, higher efficiency, and lower effective area than the reference design. For the reference design, output power of 34.2 dBm, efficiency of 20.8 %, and effective area of 63952 um2 were obtained. For design No.1, the effective area was 31511um2, which was almost half of the area occupied by the reference design. For design No.3, the efficiency was 71.2 %, which was almost 3 and half times higher than the efficiency of the reference design. Furthermore, all designs, except design NO.7, gave more or less the same output power (around 34.4 dBm).

Historical biogeography of cichlid fishes within the Usumacinta province (Mexico, Guatemala, and Belize) is reviewed based on newly collected material specifically for this study. Five areas of endemism within the province were recognized using Parsimony analysis of endemicity. Dispersal-Vicariance analysis implemented in S-DIVA suggests only one of them (the Grijalva-Usumacinta) as the ancestral area for the whole fauna. Other areas of endemism within the Usumacinta province were colonized from this area by dispersals. This biogeographic interpretation suggests a long evolution of the richest cichlid fauna in Middle America in the Grijalva-Usumacinta area of endemism in a sympatric context.

Este trabalho tem por objetivo estudar o aproveitamento do pó de aciaria elétrica (PAE) na sinterização de minério de ferro visando a eliminação de zinco. Primeiramente, foi feita uma caracterização física e química do resíduo através de análises químicas, granulométricas, morfológicas e de difração de raios-X. O minério de ferro, principal componente do processo de sinterização, foi caracterizado através de análise química, granulométrica e de umidade. Em seguida, foram fabricadas micropelotas de 3,0 a 5,0mm de diâmetro compostas por 70% de PAE e 30% de moinha de coque, que foram classificadas por peneiramento e secas em esfufa. Depois de aglomerado, o resíduo foi incorporado na sinterização de minério de ferro em diferentes proporções, condições de processo e formas de adição (micropelotas, undersize da micropelotização com granulometria entre 1,0 e 2,0mm, ou mistura de PAE e coque em pó). A cada processo de sinterização foram retiradas amostras de sínter, os materiais foram analisados através de Microscópio Eletrônico de Varredura (MEV), macroscopia e análises químicas por espectrofotometria de absorção atômica para verificar o teor de zinco. Amostras de misturas não sinterizadas também foram submetidas a análises químicas para determinar a quantidade inicial de zinco, ou seja, verificar a quantidade de zinco contido na mistura antes do processo de sinterização. Mediante a comparação do teor de zinco das amostras não sinterizadas com os sínteres, foi possível determinar a eliminação de zinco nos ensaios realizados. Aproximadamente 92% de zinco foi eliminado (junto com os gases de saída) com a incorporação de 10% de micropelotas na mistura a sinterizar. Os resultados mostraram que a eliminação do metal no processo é proporcional à relação redutor/resíduo. / The aim of this work was to study the use of electric arc furnace dust (EAFD) in iron ore sintering process aiming zinc elimination. Firstly, physical and chemical characterizations of the waste were made using X-ray diffraction, microscopy, chemical and size analyses. Iron ore is the main component of the sintering process, this material was characterized by chemical, size and humidity analyses. After, micropellets composed of EAFD 70% and coke breeze 30% with diameters of 3.0-5.0 mm were produced, then they were dried in kiln and classified by sieving. The pellets were incorporated into the iron ore sintering charge using differents proportions, process conditions and addition forms (micropellets, undersize with diameters of 1.0-2.0 mm, or a mixture of EAFD and coke breeze). Sintered samples were collected in each sintering process. These materials were analyzed by scanning electron microscopy (SEM), macroscopy and chemical analysis using atomic absorption spectrophotometry in order to determine the zinc content. Samples of not sintered mixtures were also characterized by chemical analysis aiming the determination the initial amounts of zinc, i.e. in order to check the zinc amounts present in the mixture before the sintering process. The comparation between the zinc contents of sintered samples and not sintered allowed to determine the elimination of zinc during the experiments. About 92% of zinc was eliminated (along with the output gas) with the incorporation of 10% of micropellet in the sintering mixture. Results showed that the zinc elimination in the process is proportional to the ratio reducer/waste.

Made available in DSpace on 2014-06-12T15:04:54Z (GMT). No. of bitstreams: 2 arquivo4499_1.pdf: 911403 bytes, checksum: 7991d2a32654a7dd7be890d03c0e5a9e (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2002 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / No Brasil, a evolução geomorfológica imposta pelas flutuações climáticas do Quaternário explica parte da atual distribuição da biota. Então, foi realizada uma Análise de Parcimônia de Endemismo (PAE) para analisar o padrão de distribuição da flora do Centro de Endemismo Pernambuco a partir de uma abordagem histórica. Três cladogramas mais parcimoniosos foram encontrados. A árvore de consenso para estes cladogramas, gerada pelo método Nelsen, sugeriu uma separação basal cladisticamente bem suportada entre a floresta Amazônica e a floresta Atlântica costeira, dividindo o Centro de Endemismo Pernambuco em duas sub-regiões, a floresta Atlântica de terras baixas e floresta Atlântica montana. Entre os brejos, a separação ocorreu nos limites dos brejos de Pesqueira e Brejo da Madre de Deus. Estes resultados sugerem que o surgimento de barreias climáticas e ecológicas durante as expansões e retrações da floresta úmida teria influenciado de forma significativa à distribuição das plantas lenhosas no Nordeste brasileiro. Então, são apresentadas razões pelas quais planos de conservação envolvendo conexões por corredores devem considerar os mais recentes relacionamentos históricos entre as localidades. Além disso, como no Nordeste não existem modelos sobre os quais sejam possíveis testes de congruência entre os cladogramas gerados neste estudo, o modelo aqui encontrado é proposto como ponto de partida para novas investigações biogeográficas envolvendo outros grupos taxonômicos

Made available in DSpace on 2014-06-12T15:05:24Z (GMT). No. of bitstreams: 2 arquivo4652_1.pdf: 727749 bytes, checksum: 98266a253c7792c57233b626f106015c (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2003 / No presente trabalho foi testada a hipótese de D. Andrade-Lima, segundo a qual as espécies arbóreo-arbustivas da floresta Atlântica do Sul-Sudeste do Brasil estão presentes no Centro de Endemismo Pernambuco, com maior freqüência nas florestas serranas. Foi testada, também, a hipótese de que as florestas serranas do Centro Pernambuco apresentam relações históricas mais estreitas com a floresta Atlântica do Sul-Sudeste do que com a floresta de terras baixas do referido Centro. Foi gerado uma lista base de espécies co-ocorrentes entre essas duas unidades biogeográficas, a qual foi submetida a análises de distribuição altitudinal no Centro Pernambuco. A Análise de Parcimônia de Endemismo (PAE) foi utilizada para encontrar as relações históricas entre distintos núcleos florestais. Pudemos observar um percentual significativamente maior (62%) de espécies ocorrendo exclusivamente nas florestas serranas do Centro Pernambuco. As relações históricas encontradas ratificaram o padrão altitudinal testado, bem como apontaram para uma maior proximidade entre as florestas serranas do Agreste e a floresta de terras baixas no Centro Pernambuco. A hipótese de D. Andrade-Lima foi corroborada e o padrão de distribuição sulatlântico-nordestino apresenta-se cladisticamente estruturado e estatisticamente comprovado

The thesis Phthalates in yoghurts during storage focuses on monitoring of phthalic acid esters in yogurt samples in relation to their storage period. The analyzed phthalates are di-2-(ethylhexyl)-phthalate (DEHP) and di-n-butyl-phthalate (DBP), which are among the most commonly used polymeric plasticizers, especially polyvinyl chloride. I analyzed samples of yoghurt with 1 % and 5 % chia and bamboo fiber and then subsequently compared them with natural yogurts. In total, I analyzed 120 samples of yoghurt, for which I measured DBP concentrations ranging from 0.2 mg.kg-1 to 7.7 mg.kg-1 of the original raw material and concentration of undetected values of DEHP in range up to 2.6 mg.kg-1 of the original raw material. While analyzing the yoghurt packaging, I measured average DBP values of 174.1 μg.dm-2 (68.0 μg.g-1 plastic) and DEHP values of 26.2 μg.dm-2 (10.2 μg.g-1 plastic). After prior preparation of samples, I used high performance liquid chromatography to do the phthalates analysis.

The thesis on the topic ''Monitoring of phthalic acid esters in agricultural soil'' is focused on the contamination of the agricultural soils by dibuthyl phtalate (DBP) and di (2-ethylhexyl) phthalate (DEHP). This thesis was created in cooperation with the Central Control and Testing Institute of Agriculture as a part of annual soil monitoring of organic contaminants. Forty soil samples were taken in February and March of 2017. The monitoring was carried in twelve regions of the Czech Republic. Samples were extracted using sonication and mixture of acetone-hexane (1:1). Samples were analyzed by liquid chromatography with UV detection. The measured concentrations ranged for DBP from 0,01 to 0,53 mg.kg-1 dry weight and for DEHP from 0,00 to 0,65 mg.kg-1 dry weight. None of these concentration levels exceeded the values set by the Ministry of Environment of the Czech Republic and stated in its Guideline, based on the RSL (Regional Screening Levels) published by the United States' Environmental Protection Agency (USEPA).