NON-TECTONIC SYSTEMS: CURVED STRUCTURES VAULTS, DOMES AND BARREL-VAULTS

Our present study - the concluding fifth in the series of articles to introduce the non- tectonic systems and the first to extend research into the field of the curved structures - expounds the methodology of how to connect in practice the adaptation of vaults, domes and barrel-vaults with the non-tectonic building methods on the industrial level. It is evident that the non-tectonic building, already by virtue of its universality, cannot give up using forms of spaces which enrich architecture in any case, but it is also evident that it cannot renounce the standpoints of industrialization of building either. The non-tectonic systems are based on the recognition that tectonics is not the only possible axiom of building and the adaptation of curved structures gives a further proof that such an axiomatic change is realizable and that we may open new hitherto unknown ways of industrialization of building if we break with the axiom of tectonics

CHARACTERISTIC FEATURES OF THE NON-TECTONIC SYSTEMS (THESES)

The actual theme of the theses summarizingly denominated as "Characteristic features of the non-tectonic systems" is the mass adaptation of the non-tectonic systems, or rather some fundamental theoretical and practical problems of the adaptation. The theses are expounded in an expedient rhythm, in so far as they summarize the characteristic features of the non-tectonic systems through grouping them around definite problems. Theses 1-3 deal ,vith the "status", - i.e.: the proper place - of the non-tectonic systems. Here, first of all, we define the "genus proximum" of the system and then on this basis we start expounding the features, that is the "differencia specifica" of the system. Thesis 4-6 analyse the architectural efficacy of the non-tectonic systems and point out why and to what degree the specific complementarity hidden within theses systems endow the non-tectonic systems with a particular significance in the industrialized building. Theses 7-9 give an analysis of the principles of additivity and disintegration, that is the two universal, axiomatic and internative principles of building and prove that the non-tectonic systems by combining the two diagonally opposite principles of construction of industrialized building (that is the principle of component and the principle of coach-work) maintain their characteristic openness at all events (even if availing themselvcs with a possible closedness, if that is expedient). Theses 10-12 finally examine the two fundamental and complementary systems of industrialized building - the system of co-ordination and the system of tolerances from the point of view of non-tectonic building and on this basis and as a summary of what has been said - determine the basic methods of non-tectonic building and mark out thereby their terrain the industrialized building

Adsorption of organic acids on magnetite nanoparticles, pH-dependent colloidal stability and salt tolerance

The adsorption of different organic acids and their influence on the pH-dependent charging, salt tolerance and so the colloidal stability of magnetite nanoparticles are compared. Adsorption isotherms of citric acid - CA, gallic acid - GA, poly(acrylic acid) - PAA, poly(acrylic-co-maleic acid) - PAM and humic acid - HA were measured. The pH-dependent charge state of MNPs was characterized by electrophoretic mobility and their aggregation by dynamic light scattering. The salt tolerance was tested in coagulation kinetic experiments. Although the adsorption capacities, the type of bonding (either H-bonds or metal ion-carboxylate complexes) and so the bond strengths are significantly different, the following general trends have been found. Small amount of organic acids at pH. <. ~8 (the pH of PZC of magnetite) - relevant condition in natural waters - only neutralize. s the positive charges, and so promotes the aggregation and sedimentation of nanoparticles. Greater amounts of organic acid, above the charge neutralization, cause the sign reversal of particle charge, and at high overcharging promote stabilization and dispersing. The thicker layer of PAA, PAM and HA provides better electrosteric stability than CA and GA. GA undergoes surface polymerization, thereby improving stabilization. The organic acids studied here eliminate completely the pH sensitivity of amphoteric magnetite, but only the polyanionic coverage provides significant increase in resistance against coagulating effects of salts at neutral pH commonly prevailing in natural waters