Caracterização experimental de uma bomba ejetora

A opção de futuro incide sobre os processos de combustão em regime pobre e com baixos índices de formação de poluentes. Neste contexto, o presente trabalho estuda um ejetor de um queimador de gás propano, que equipa uma marmita utilizada para confeção de alimentos no Exército Português, para compreender o mecanismo de arrastamento de ar, com vista a identificar as causas que possam contribuir para uma diminuição da razão de equivalência da mistura ar/combustível. Estes queimadores são dispositivos de funcionamento estritamente mecânico e de conceção simples que permitem uma gama de potências caloríficas compreendidas entre 8 e 22 kW. Permitem uma boa estabilidade de chama que é um requisito fundamental de segurança. A regulação de potência é executada através de uma válvula de ajuste, contendo três posições, uma em que a alimentação se encontra cortada e as outras duas permitindo funcionar na potência mínima e máxima. De modo a efetuar o estudo do ejetor, numa primeira fase, submeteu-se o sistema a uma caracterização experimental do campo de escoamentos à entrada de ar do ejetor, a partir da técnica de diagnóstico Particle Image Velocimetry (PIV). Assim avalia-se de que forma o escoamento de ar exterior influencia o comportamento do escoamento da mistura de ar/combustível à saída do queimador. Numa segunda fase, recorre-se à técnica de diagnóstico Quimiluminescência para medição de espécies químicas, para avaliar o comportamento do ejetor a alterações de vários parâmetros, tais como caudal de combustível, área de entrada de ar e área de saída da mistura do difusor. Conclui-se que o ejetor mostrase "insensível" a alterações da área de saída e de entrada de ar, em relação ao valor médio da razão de equivalência. Porém observa-se que as misturas de ar/combustível são mais homogéneas quando as áreas de entrada, da saída e da garganta têm valores próximos.

Graphical remote-access simulation system (GRASS), the communication and monitor components (GASP/GLASP).

"Supported in part by contract U.S. AEC AT(11-1)1469."

Illiac III reference manual.

"C00-2118-0005" (v. 1)

DEC PDP-8 interface to IBM 2701 PDA

"C00-1469-0153."

A failure tolerant filing system,

"COO-1469-0200."

RASER: random to serial converter.

"COO 1469-0209."

DEC PDP-7 Interface to IBM 2701-PDA,

"C00-1469-0116"

The pattern articulation unit of Illiac III: simulation,

"COO-1018-1154."

Semantrix : a semantically guided digital electronic machine /

Thesis (M. S.)--University of Illinois at Urbana-Champaign.

Memory-processor connection networks.

Vita.

Supplement to CAMAC (computer automated measurement and control) standards and reports /

Issued Mar. 1978.

Economic effects of metallic corrosion in the United States.

Appendix C published in PB-279 430.

IAS/RSX-11 I/O operations reference manual.

Includes index.

Out-of-School English and the possible effect it has on Second Language Acquisition : - a study on how students with different backgrounds acquire the English language outside of school

Second language acquisition is a field that has fascinated linguists for numerous years and is a topic that is very much connected to how English teachers in Sweden try to teach the English language to the students in their classrooms. In 2009 Sundqvist examined what possible effects extramural English could have on learners' oral proficiency and their vocabulary. In her study she found out that extramural English “is an independent variable and a possible path to progress in English” (Sundqvist, 2009, p. i).  In 2014, three Swedish secondary- and upper secondary school teachers started a project for the Erasmus+. These three teachers tried to create better teaching conditions and to come up with new methods for teaching English. During their investigation they noticed that students who had only been in Sweden for four years or less, seemed to get less exposed to English in their spare time than native Swedish students, which created a disadvantage for them. Since the time when these two studies were carried out, the number of immigrants has increased drastically, which creates the need for further investigation within this area of second language acquisition. In this study, I therefore investigate how much and in what way students come in contact with the English language outside of school. I also examine if there are any differences between native Swedish students versus non-native Swedish students and if so, how this might affect the students and their grades in English. The study was conducted through the use of questionnaires and through observations of different teaching situations, including the participating teachers' methods and the participating students' reactions. The results show that there are differences between native- and non-native students when it comes to extramural English activities. The results also show that these differences seem to affect the students' grades in English, in favour of the native Swedish students. The native students tend to spend more time on extramural English activities, especially in connection to the Internet and computer games, than the non-native students. These results indicate that something needs to be done in order to compensate for the non-native students' disadvantage.

The Social and Economic Impacts of a Washington State Carbon Tax

Thesis (Master's)--University of Washington, 2016-06