'What attitude should a government have towards religion?' was not only a question that governments had struggled with for ages, but one currently growing in significance. J.M. Vorster identified five options that different governments had chosen and he selected the so-called 'active-plural option' as his preference. This option allowed governments to make provision for all religions or traditions, without the promotion of any specific one. Article 36 of the Belgic Confession (1561) represents a foremost statement of what the Reformed tradition believed governments were being called to. This study therefore investigated the suitability of the 'active-neutral option' for the implementation of article 36. This was done while exploring the specific circumstances within and goal with which the confession was formulated; the most important changes to the text of article 36 (1905, 1982) as well as its corrected meaning. Whereas there was a time when governments were seemed to have the task to, amongst others, destroy all idolatry and false worship, it was stated in 1982 that governments (only) had to protect the proclamation of the Gospel and in so doing achieved this destruction. All governments received their authority from God and were to be his faithful servants - without becoming servants of any church and/or tradition.

'Wat behoort 'n owerheid se ingesteldheid ten opsigte van godsdiens te wees?' is 'n vraagstuk waarvoor owerhede millennia lank reeds staan en wat tans al meer akuut word. J.M. Vorster het vyf opsies geïdentifiseer wat owerhede se ingesteldheid vergestalt en verkies die sogenaamde 'aktief-plurale' opsie. Hiervolgens behoort owerhede alle godsdienste en/of tradisies toe te laat en geeneen in besonder te bevoordeel nie. Artikel 36 van die Nederlandse Geloofsbelydenis (1561) verteenwoordig 'n vername verwoording van waartoe die Reformatoriese tradisie glo owerhede geroep word. Hierdie studie het dus die geskiktheid van die aktief-plurale opsie vir die toepassing van artikel 36 ondersoek. Die fokus van die ondersoek was op die agtergrond waarbinne en die doel waarmee die belydenis geformuleer is; die belangrikste tekstuele veranderinge (1905, 1982); asook die korrekte betekenis van artikel 36. Daar is vir lank gemeen dat owerhede onder meer die taak het om alle afgodery en valse godsdiens uit te roei. Sedert 1982 word bely dat owerhede (slegs) die verkondiging van die Evangelie moet beskerm om hierdie doelwitte sodoende te bereik. Alle owerhede ontvang hulle gesag van God en moet sy getroue dienaars wees - sonder om 'n dienaar van enige kerk en/of tradisie te word.

Neste trabalho, filtros com estrutura fibrosa foram produzidos utilizando-se matéria-prima de baixo custo, disponível comercialmente e caracterizados para aplicações em filtração de aerossóis. Mantas refratárias sílico-aluminosas comerciais foram prensadas uniaxialmente, utilizando-se 10% em massa de acetato de polivinila como ligante. Nesta etapa, as amostras foram submetidas à compactação com diferentes pressões para obtenção de diferentes porosidades. Após a prensagem, as amostras foram submetidas a um tratamento térmico a 500 ºC durante 1 h para a degradação do polímero. Subseqüentemente, as amostras foram sinterizadas a 1200 ºC durante 1 h, resultando em uma estrutura fibrilar porosa, composta por mulita (3SiO2.2Al2O3), com porosidade na faixa de 50 a 75%. A morfologia dos filtros fibrosos foi caracterizada através de microscopia eletrônica de varredura, que revelou uma estrutura tridimensional porosa de fibras interconectadas. A resistência mecânica foi avaliada através de ensaios de compressão e de flexão em quatro pontos. Ensaios de permeabilidade e eficiência de coleta de partículas com diferentes diâmetros foram efetuados e os resultados comparados a filtros comerciais. Os valores obtidos para a permeabilidade e eficiência de coleta estão na ordem de grandeza esperada para filtros de gases, apresentando assim grande potencial para aplicações industriais.

Filters with fibrous structure were produced from low cost, commercially available raw materials and characterized for aerosol filtration. Refractory aluminosilicate fibers were uniaxially pressed with polyvinyl acetate as binder. Different pressures were applied, which yielded samples with different porosities. After pressing, the samples were heat treated at 500 ºC during 1 h in air for debinding with subsequent sintering at 1200 ºC for 1 h, which resulted in porous fibrous structures composed mainly by mullite (3SiO2.2Al2O3) with porosity in the range of 50%-75%. The microstructure of the fibrous filters was evaluated by scanning electron microscopy, which revealed a porous morphology comprised by three-dimensional interconnected fibers. Mechanical strength was measured by compressive and 4-point bending tests. Permeability and particle collection efficiency were evaluated and compared with commercially available filters. The permeability and collection efficiency values are in the order of magnitude of cellular supports for aerosol filters and, therefore, suitable for several technological applications.