RAW MATERIALS FOR GEOPOLYMERISATION

Geopolymers are inorganic alumina-silicate materials with excellent physical and chemical properties. Despite being a rather recent research topic, many papers and books have been published focusing on various aspects of geopolymerisation: the history, properties, production, raw materials, applications and development of geopolymers. A brief overview of geopolymer technology is presented in the article, emphasising the great variety of raw materials that can be used for geopolymer production. Considering the variety of the origin of these materials, three categories are distinguished: primary raw materials which consist of natural minerals, secondary raw materials which are industrial wastes and by-products, and wastes and by-products of natural origin. In spite of not being widely accepted by the industry yet, geopolymerisation has the potential to become a valuable waste-recycling technology in the future

Stability of an elastic supported flat plate subjected to potential flow

In this paper we investigated the dynamics of a thin, flat plate placed in potential planar flow and attached by springs to the wall. %The length of %the plate in the direction perpendicular to the plane of flow was considered %to be infinite. Furthermore, the centre of gravity of the plate was assumed to move only perpendicular to the direction of the flow. Thus, a two-degree-of-freedom oscillatory system was analysed, whose natural frequencies depend on the flow velocity. The equations of motion were derived for two cases: first, the flow forces acting on the plate were determined using a quasi-steady approach; in the second case, we used the formulas derived by Theodorsen assuming unsteady potential flow. Finally, we obtained and compared the stability charts for the two cases

The development of fly ash – red mud based geopolymer

Taking into account environmental considerations, such as decreasing CO2 emission and the ecological footprint, the utilisation of secondary raw materials is essential for sustainable development. Fly ash is the product of coal combustion plants that is collected by various air cleaning equipment from flue gas, and red mud is the by-product of the Bayer-process, through which alumina can be produced from bauxite. Geopolymerisation is a process that is suitable for the utilisation of such wastes to produce ceramics, cement, concrete etc. with many advantageous properties. The main objective of the article is to present data on the development and examination of geopolymer made out of deposited fly ash from Tatabánya and red mud from Almásfüzitő. During the experiments, red mud was added to previously optimised fly ash geopolymer in various quantities and compressive strength tests were carried out to determine the optimal fly ash and red mud ratio. However, as the cracking of the specimens could be observed, further tests were carried out on the durability of the geopolymers. The effect of the sealing conditions and RM calcination was investigated, both via visual inspection and with FT-IR analysis at the ages of 3, 7, 14, 28 and 90 days. Based on the results, it could be concluded that the sealing conditions have direct effect on the structural characteristics of fly ash – red mud based geopolymers, but further experiments should be carried out for the identification of the ongoing reactions

Stability study of nasal powder formulation containing nanosized lamotrigine

Drug administration through the nose offers great possibilities which have been discovered in the past few decades. Besides the most known local effect, systemic and central nervous system effect is also available, the administration is non-painful and the degradation effect of the gastrointestinal tract can be avoided. Amongst the nasal formulations, powders have become more popular as their stability is favorable compared to the liquid formulations and a higher doses can be administered in powder form. The quality insurance and stability of the products in the pharmaceutical field have gained considerable attention in the last decades. Due to this fact, the aim was to execute a long-term stability study of a previously developed, nanosized lamotrigine (LAM) containing nasal powder (NP) formulation. The results of the stability test showed that the NP formulation preserved its key properties (particle size, morphology, structure and in vitro drug release) after 6 months of storage

Az implicit tanulás és a nyelvi képességek kapcsolata

A tanulmány az implicit tanulás és a mondatmegértés kapcsolatát vizsgálja kettős terheléses kísérleti helyzetben. A kísérleti személyeknek az implicit tanulási feladattal - szeriális reakcióidő (SRT) — párhuzamosan mondatmegértési, szófeldolgozási, és matematikai feladatokat kellett végrehajtaniuk. Az implicit tanulási teljesítmény a mondatmegértési feladat közben szignifikánsan rosszabb volt, mint a kontroll helyzetekben. Az eredmények összhangban vannak PINKER és ULLMAN procedurális/deklaratív elméletével. The main purpose of this research is to study the relationship between implicit learning and sentence processing. The authors present a dual-task experiment, in witch the subject's implicit learning was measured by a serial reaction time (SRT) task, and at the same time subjects were tested on sentence processing, word processing, and mathematical tasks. Results show that implicit learning is significantly worse when the parallel task was sentence processing than when it was either nonword-detection or counting. These findings are interpreted in the framework of Pinker and Ullman's procedural/declarative