Online social networks and location: dual effect of distance on user rate and average number of connections in Hungary

Online social networks (OSN) are major platforms of ICT-enabled communication, supporting place-independent social life; however, recent findings suggest that geographical location of users strongly affect network topology. Therefore, OSNs may be simultaneously related to locations and also unlocked from offline geographies. Our paper addresses this dual-faced phenomenon analysing location-specific impact on the user rate of online communities and average number of online friends. Findings on iWiW, a leading OSN in Hungary with more than 4 million users, suggest that user rate is positively associated with geographical proximity of Budapest, the single decisive urban centre in the country. On the other hand, the average number of connections is independent from geographical proximity of the capital and it is even higher in peripheral regions when controlling for other offline factors

Online social networks, location, and the dual effect of distance from the centre

Online social networks (OSN) are major platforms of ICT-enabled communication, supporting place-independent social life. However, recent findings suggest that the geographical location of users strongly affects network topology. Therefore, OSNs may be simultaneously related to locations and also unlocked from offline geographies. Our paper addresses this dual-faced phenomenon, analysing the location-specific effect on OSN diffusion and OSN usage. Findings on iWiW (International Who Is Who), the leading OSN in Hungary in the 2000s with more than 4 million users, suggest that the rate of users (proxy for OSN diffusion) is positively associated with the geographical proximity of Budapest, the foremost urban centre in the country. On the contrary, the average number of connections (proxy for OSN usage) is independent of the geographical proximity of the capital, and it is even higher in peripheral regions when controlling for other offline factors. © 2015 Royal Dutch Geographical Society KNAG

Long-term durability tests of andesite aggregates from Hungary

The Micro-Deval test method is used for testing of aggregate durability. The present paper focuses on two Hungarian andesites obtained from the quarries of Recsk (Mátra Mountains, Hungary) and of Nógrádkövesd (Cserhát Mountains, Hungary). The aim of this study is to find a simple test method based on the original Micro-Deval test method to assess the long-term durability of aggregates. An additional part of the research was to develop suitable mathematical models that can describe the behavior of the andesite aggregates under continuous abrasive impact. The relevant standard (EN 1097-1:2012) recommends 12,000 rotations to determine the Micro-Deval coefficient required for classification of the aggregates. Within the framework of this research, a modified Micro-Deval test was applied: the number of rotations was increased in several steps and the degree of abrasion was measured afterwards. Regression analyses were used to outline mathematical forms which characterize the dependence between the number of rotations and the degree of abrasion. According to the results, the long-term Micro-Deval tests significantly modify the assessed durability and thus provide information on the long-term abrasive impact. The degree of change depends on the studied material: the ratio of the long-term Micro-Deval coefficients of the two studied andesite types is larger than 3. The regression analyses of the measured Micro-Deval coefficients revealed that quadratic curves are suitable to describe these tendencies for both andesite aggregates

Porosity and compatibility of repair mortars and Hungarian porous limestones

Abstract Porosity and water absorption of different binder/aggregate ratios of repair mortar and porous limestone were studied that were used in many Hungarian monuments. Different types of mortars were analyzed by using mercury intrusion porosimetry (MIP) and the water saturation method (WSM). Test results showed that there was a strong correlation between the absorption mechanism and the porosimetric characteristics. Mechanical properties of the tested mortars were observed earlier. Pore size distribution confirms that the total porosity increases with increasing aggregate content. Natural stones mainly have medium and large pore radii (1–100 μm) while repair mortars, even with increased aggregate ratio, have smaller pore radii (0.01–0.1 μm). The comparison of different data allows us to state that pore characteristics such as pore volume, pore geometry, pore size distribution and network connectivity are the key control factors of stone and mortar deterioration