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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Výroba vodíku z biomasy / Hydrogen Production from Biomass

Ožana, Ferdinand January 2010 (has links)
First part of this master´s thesis decribes the basic properties of hydrogen, its utilization in industry and economy. Greater attention is focused on the possibilities of hydrogen produciton. Next part describes anaerobic fermentation and optimum conditions for hydrogen production. The main part of the thesis deals with posibility of hydrogen production in an experimental laboratory unit using brewer´s grains as a primary material. The experiment was aimed to find suitable process conditions for hydrogen production. The quantity of produced gas and his quality depending on the amount of brewer´s grains and frequency of the dosage was observed. Based on the experiment, some recommendations are proposed for further research. An automatic feeding system is the most important of them. It will improve the quality of experimental work. A separate chapter is devoted to the automatic feeding system.
12

EFEITO SECUNDÁRIO DO BURACO DE OZÔNIO ANTÁRTICO SOBRE O SUL DO BRASIL / INFLUENCE OF THE ANTARCTIC OZONE HOLE EPISODE OVER SOUTHERN OF BRAZIL

Peres, Lucas Vaz 01 February 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In this Dissertation were identified events of influence of the Antarctic ozone hole over the South of Brazil that occurred in the period between 1979 and 2011. For this, we analyzed the daily average data of total ozone column obtained through the Brewer Spectrophotometers MKIV #081 model during the period 1992-2000, MKII model #056 of 2000-2002 and MKIII #167 model from 2002 to the present day, installed in the Southern Space Observatory- OES/CRS/INPE MCTI (29,4 °S; 53,8°O; 488,7m) and by satellite instruments Total Ozone Mapping Spectrometer (TOMS) and Ozone Monitoring Instrument (OMI) to the same latitude of the southern Space Observatory in the absence of surface equipment data, searching for days of falls in ozone content. For these days, isentrópicas analyses were conducted of potential vorticity using Reanalysis data provided by the National Centers for Environmental PredictionAtmospheric Research (NCEPNCAR), in order to verify the origin of ozone-poor air mass. Confirmation of the origin of polar air masses took place through the analysis of the trajectories retroactive made through the Hysplit model of NOAA. In addition, it was also conducted a complementary analysis through the pictures of the ozone content of TOMS and OMI, the ozone hole in the Antarctic region and its connection to the South of Brazil. The methodology used was effective in the identification of 66 events of the Influence of Antarctic Ozone Hole over south of Brazil, which showed an average drop of 8.66 ± 3.13 in the ozone content. The identification of the stratospheric circulation pattern through the medium of the vorticity field potential for the occurrence of the phenomenon was performed. In addition, were shown an analysis of synoptic weather troposphere during the occurrence of two events, noting that in both cases, the events occurred in a situation front post on the South of Brazil, coupled with the passage of the input region polar polar or subtropical jet stream, characterized by the occurrence of the event of the tropopause folding where stratospheric air intrusion occurs in the troposphere, and advancement of a high-pressure front post system that prevents the formation of significant cloud cover. Leveraging the operating environment of the Atmospheric Modeling Group (GRUMA) at the Federal University of Santa Maria (UFSM), using data from the output of numerical weather forecasting model Global Forecast System (GFS) in making maps of potential vorticity, can carry out effectively the clue of the forecast arrival of stratospheric air masses of polar origin on the southern Brazil during the spring of the year of 2012 with at least four days in advance, coinciding with the events of transport these side effects of the Antarctic ozone hole over the South of Brazil identified in the current year. / Na presente Dissertação foram identificados os eventos de Efeito Secundário do Buraco de Ozônio Antártico ocorridos sobre o Sul do Brasil no período entre 1979 e 2011. Para isso, foram analisados os dados médios diários da coluna total de ozônio obtidos através dos Espectrofotômetros Brewer modelo MKIV #081 durante o período de 1992 2000, modelo MKII #056 de 2000 2002 e modelo MKIII #167 de 2002 até os dias atuais, instalados no Observatório Espacial do Sul OES/CRS/INPE MCTI (29,4 °S; 53,8°O; 488,7m) e pelos instrumentos de satélite Total Ozone Mapping Spectrometer (TOMS) e Ozone Monitoring Instrument (OMI) para a mesma latitude do Observatório Espacial do Sul na falta de dados do equipamento de superfície, buscando dias de quedas no conteúdo de ozônio. Para estes dias, foram realizadas análises isentrópicas de vorticidade potencial utilizando dados de reanálise fornecidos pelo National Centers for Environmental Prediction/Atmospheric Research (NCEP/NCAR), a fim de verificar a origem da massa de ar pobre em ozônio. A confirmação da origem polar das massas de ar deu-se através da análise das trajetórias retroativas confeccionadas através do modelo Hysplit da NOAA. Além disso, foi também realizada uma análise complementar através das imagens do conteúdo de ozônio dos satélites TOMS e OMI, verificando-se a atuação do Buraco de Ozônio na região Antártica e sua conexão com o Sul do Brasil. A metodologia empregada mostrou-se eficaz na identificação de 66 eventos de Efeito Secundário do Buraco de Ozônio Antártico sobre o Sul do Brasil, os quais apresentaram uma queda média de 8,66 ± 3,13 % no conteúdo de ozônio. Foi realizada a identificação do padrão de circulação estratosférica através da confecção do campo médio da vorticidade potencial para os dias de ocorrência do fenômeno. Além disso, foram mostradas as analises das condições sinótica troposférica durante a ocorrência de dois eventos, observando-se que em ambos os casos, os eventos ocorreram em uma situação pós frontal sobre o Sul do Brasil, associada à passagem da região de entrada polar da corrente de jato subtropical ou polar, caracterizada pela ocorrência de evento de quebra da tropopausa onde ocorre intrusão de ar estratosférico para dentro da troposfera, e avanço de um sistema de alta pressão pós frontal que impede a formação de nebulosidade significativa. Aproveitando o ambiente operacional do Grupo de Modelagem Atmosférica (GRUMA) da Universidade Federal de Santa Maria (UFSM), utilizando dados da saída do modelo de previsão numérica de tempo Global Forecast System (GFS) na confecção de mapas de vorticidade potencial, pode-se realizar eficazmente a previsão do indício da chegada de massas de ar estratosféricas de origem polar sobre o Sul do Brasil durante o período da primavera do ano de 2012, com pelo menos quatro dias de antecedência, coincidindo estes transportes com os eventos de Efeito Secundário do Buraco de Ozônio Antártico sobre o Sul do Brasil identificados no corrente ano.
13

Impact of Rossby waves on ozone distribution and dynamics of the stratosphere and troposphere

Nikulin, Grigory January 2005 (has links)
<p>Several physical mechanisms concerning the impact of Rossby waves on ozone distribution and circulation in the stratosphere and troposphere are studied in the thesis.</p><p>Summertime total ozone variability over Middle Asia and Northern Scandinavia shows similar wave-like behaviour with typical periods of 10-20 days and amplitudes of 20-50 Dobson units. These variations are caused by eastward travelling Rossby waves in the lower stratosphere. The same mechanism plays the primary role in the formation of an intense low ozone episode over Scandinavia in August 2003. A strong anticyclone was formed in the troposphere over Europe as a part of a Rossby wave train. The anticyclone coincides with a displaced Artic pool of low-ozone air in the stratosphere aloft of the anticyclone. A combination of the two above-mentioned processes results in the total ozone minimum over Northern Europe for summer 2003.</p><p>Interannual variability of the atmospheric circulation and total ozone during winter is strongly controlled by the diabatic (Brewer-Dobson) circulation which is driven by upward propagating waves from the troposphere. In the Northern Hemisphere midlatitudes, wintertime total ozone shows antiphase behaviour with the Arctic Oscillation (AO) index on interannual and decadal time-scales. Weaker (stronger) wave activity leads to less (more) northward ozone transport and to a stronger (weaker) AO.</p><p>Rossby wave activity occurs as episodic wave events and this wave forcing is not uniform during winter. The November-December stratospheric eddy heat flux is strongly anticorrelated with the January-February eddy heat flux in the midlatitude stratosphere and troposphere. Weaker upward wave fluxes in early winter lead to stronger upward wave fluxes from the troposphere as well as to a stronger polar night jet during midwinter and vice versa. Hence upward wave activity fluxes in early winter define, to a considerable extent, the subsequent evolution of the midwinter circulation in the stratosphere and troposphere.</p>
14

Impact of Rossby waves on ozone distribution and dynamics of the stratosphere and troposphere

Nikulin, Grigory January 2005 (has links)
Several physical mechanisms concerning the impact of Rossby waves on ozone distribution and circulation in the stratosphere and troposphere are studied in the thesis. Summertime total ozone variability over Middle Asia and Northern Scandinavia shows similar wave-like behaviour with typical periods of 10-20 days and amplitudes of 20-50 Dobson units. These variations are caused by eastward travelling Rossby waves in the lower stratosphere. The same mechanism plays the primary role in the formation of an intense low ozone episode over Scandinavia in August 2003. A strong anticyclone was formed in the troposphere over Europe as a part of a Rossby wave train. The anticyclone coincides with a displaced Artic pool of low-ozone air in the stratosphere aloft of the anticyclone. A combination of the two above-mentioned processes results in the total ozone minimum over Northern Europe for summer 2003. Interannual variability of the atmospheric circulation and total ozone during winter is strongly controlled by the diabatic (Brewer-Dobson) circulation which is driven by upward propagating waves from the troposphere. In the Northern Hemisphere midlatitudes, wintertime total ozone shows antiphase behaviour with the Arctic Oscillation (AO) index on interannual and decadal time-scales. Weaker (stronger) wave activity leads to less (more) northward ozone transport and to a stronger (weaker) AO. Rossby wave activity occurs as episodic wave events and this wave forcing is not uniform during winter. The November-December stratospheric eddy heat flux is strongly anticorrelated with the January-February eddy heat flux in the midlatitude stratosphere and troposphere. Weaker upward wave fluxes in early winter lead to stronger upward wave fluxes from the troposphere as well as to a stronger polar night jet during midwinter and vice versa. Hence upward wave activity fluxes in early winter define, to a considerable extent, the subsequent evolution of the midwinter circulation in the stratosphere and troposphere.
15

Proměnlivost Brewerovy-Dobsonovy cirkulace / Variability of the Brewer-Dobson Circulation

Kupčihová, Zuzana January 2017 (has links)
The middle atmosphere transport is mostly controlled by a large-scale meridional circulation, namely the Brewer-Dobson circulation. In this thesis, climatology and variability of the Brewer-Dobson circulation and the middle atmosphere has been analysed using the Canadian Middle Atmosphere Model (CMAM30-Ext). A number of key variables are used including the age of air, residual velocities, residual stream function, temperature and zonal wind. The analysis of the climatology of the age of air shows, in particular, that young air gets generated near the tropical tropopause, which then travels poleward. The residual stream function shows that the Brewer-Dobson circulation dominates the winter hemispheres around the solstices and becomes nearly symmetrical, with respect to the equator, around the equinoxes. The empirical orthogonal function analysis is applied to explore the modes of variability in the middle atmosphere. The analysis identifies, in particular, the semi-annual oscillation, the quasi-biennial oscillation with moderate explained variance compared to the variance explained by the annual cycle. In addition, the analysis also reveals the emergence of the solar cycle. Powered by TCPDF (www.tcpdf.org)
16

Caracterização e viabilidade econômica do bagaço de malte oriundo de cervejarias para fins energéticos / Characterization and economic viability of bagasse coming from malt beer for energy purposes.

Cordeiro, Luana Gomes 12 September 2011 (has links)
Made available in DSpace on 2015-04-17T14:49:14Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2605589 bytes, checksum: d958d98e8d432a97a6c6392aa35de6d0 (MD5) Previous issue date: 2011-09-12 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work aimed to study the energy capacity of the cake originating from malt beer at different moisture levels for energy, through description and analysis of economic viability. Sample collection was made in a company located in the city of João Pessoa-PB. Physical and chemical analysis were carried out to determine the chemical composition, where it was found their consumption potential for both animal feed and for human consumption. The immediate analysis showed high levels of volatile materials and low content of fixed carbon. The samples were characterized according to the humidity, higher calorific value and density. Moisture content were obtained (50%, 40%, 30%, 20% and 15%) and gross calorific value ranging from 2656 to 5025 kcal.kg-1 for the highest and lowest humidity respectively. The proposed regression model was able to express in more than 98% the relationship between higher calorific value and moisture content, and more than 92% compared to gross calorific value and density. With regard to economic feasibility, can be seen that all schemes of work proposed for the new working configuration of boilers were viable and the most profitable decreased by 49.98% in the cost of natural gas, that is, an economy R$ 3,900,842.00 per year. You can check that the malt bagasse as an energy source is feasible. / Este trabalho teve como objetivo estudar a capacidade energética do bagaço de malte oriundo de cervevf jarias em diferentes níveis de umidade para fins energéticos, mediante caracterização e análise de viabilidade econômica. A coleta da amostra foi feita em uma empresa situada na cidade de João Pessoa-PB. Foram realizadas análises físico-químicas para determinação da composição centesimal, onde foi constatado seu potencial de consumo tanto para ração animal como para alimentação humana. A análise imediata apresentou elevados teores de materiais voláteis e baixos teores de carbono fixo. As amostras foram caracterizadas de acordo com a umidade, poder calorífico superior e densidade. Foram obtidas umidades de (50%, 40%, 30%, 20% e 15%) e poder calorífico superior variando de 2.656 a 5.025 kcal.kg-1 para a maior e menor umidade respectivamente. Os modelos de regressões propostos puderam expressar em mais de 98% a relação entre poder calorífico superior e teor de umidade e mais de 92% a relação poder calorífico superior e densidade. Com relação à viabilidade econômica, pode-se perceber que todos os regimes de trabalho propostos para a nova configuração de trabalho das caldeiras foram viáveis e o regime mais rentável apresentou uma redução de 49,98% nos custos com gás natural, ou seja, uma economia de R$ 3.900.842,00 por ano. Pode-se verificar que o bagaço de malte é viável como fonte energética.
17

The Inconsistent Continuities

Green, Julian Roger 05 May 2023 (has links)
No description available.

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